Frontiers in Bioscience

Published by Frontiers in Bioscience

Online ISSN: 1093-4715

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Print ISSN: 1093-9946

Articles


Hemostatic effects of recombinant DisBa-01, a disintegrin from Bothrops alternatus
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February 2008

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165 Reads

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A monomeric RGD-disintegrin was recently identified from a cDNA library from the venom gland of Bothrops alternatus. The corresponding 12 kDa-recombinant protein, DisBa-01, specifically interacted with alpha(v)beta3 integrin and displayed potent anti-metastatic and anti-angiogenic properties. Here, the interaction of DisBa-01 with platelet alphaIIb beta3 integrin and its effects on hemostasis and thrombosis were investigated. DisBa-01 bound to Chinese Hamster Ovary (CHO) cells expressing beta3 or alphaIIb beta3 and promoted their adhesion and the adhesion of resting platelets onto glass coverslips. The disintegrin inhibited the binding of FITC-fibrinogen and FITC-PAC-1 to ADP-stimulated platelets and inhibited ADP-, TRAP- and collagen-induced aggregation of murine, rabbit or human platelets. In a flow chamber assay, DisBa-01 inhibited and reverted platelet adhesion to immobilized fibrinogen. DisBa-01 inhibited the phosphorylation of FAK following platelet activation. The intravenous injection of DisBa-01 in C57Bl6/j mice, prolonged tail bleeding time as well as thrombotic occlusion time in mesenteric venules and arterioles following vessel injury with FeCl3. In conclusion, DisBa-01 antagonizes the platelet alphaIIb beta3 integrin and potently inhibits thrombosis.
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Transgenic approaches for the reduction of Galalpha(1,3)Gal for xenotransplantation

May 1997

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26 Reads

The major barrier to clinically successful xenotransplantation is the lack of effective therapies aimed at eliminating antibody and complement -dependent hyperacute rejection. This review examines transgenic strategies to eliminate or reduce expression of the major pig to human xenoantigen Galalpha(1,3)Gal such that the epitope is no longer recognized by natural human antibodies, by the use of glycosidases and/or glycosyltransferases that can competitively and effectively inhibit the activity of the alpha1,3galactosyltransferase gene and thereby eliminate the xenoantigen Galalpha(1,3)Gal.

Mechanism of nuclear calcium signaling by inositol 1,4,5-trisphosphate produced in the nucleus, nuclear located protein kinase C and cyclic AMP-dependent protein kinase

February 2008

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27 Reads

Nuclear phospholipase C-gamma 1 can be phosphorylated by nuclear membrane located epidermal growth factor receptor sequel to epidermal growth factor-mediated signaling to the nucleus. The function of mouse liver phospholipase C-gamma 1 is attributed to a 120 kDa protein fragment which has been found to be a proteolytic product of the 150 kDa native nuclear enzyme. The tyrosine-phosphorylated 120 kDa protein band interacts with activated EGFR, binds phosphatidyl-3-OH kinase enhancer, and activates nuclear phosphatidylinositol-3-OH-kinase, and is capable of generating diacylglycerol in response to the epidermal growth factor signal to the nucleus in vivo. Thus a mechanism for nuclear production of inositol-1,4,5-trisphophate is unraveled. Nuclear generated inositol-1,4,5-trisphophate interacts with the inner membrane located inositol-1,4,5-trisphophate receptor and sequesters calcium into the nucleoplasm. Nuclear inositol-1,4,5-trisphophate receptor is phosphorylated by native nuclear protein kinase C which enhances the receptor-ligand interaction. Nuclear calcium-ATPase and inositol-1,3,4,5-tetrakisphophate receptor are located on the outer nuclear membrane, thus facilitating calcium transport into the nuclear envelope lumen either by ATP or inositol-1,3,4,5-tetrakisphophate depending upon the external free calcium concentrations. Nuclear calcium ATPase is phosphorylated by cyclic AMP-dependent protein kinase with enhanced calcium pumping activity. A holistic picture emerges here where tyrosine phosphorylation compliments serine phosphorylation of key moieties regulating nuclear calcium signaling. Evidence are forwarded in favor of proteolysis having a profound implications in nuclear calcium homeostasis in particular and signal transduction in general.

Prion peptide 106-126 as a model for prion replication and neurotoxicity

May 2002

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56 Reads

Prion diseases or transmissible spongiform encephalopathies are neurodegenerative disorders that are genetic, sporadic, or infectious. The pathogenetic event common to all prion disorders is a change in conformation of the cellular prion protein (PrPC) to the scrapie isoform (PrPSc), which, unlike PrPC, aggregates easily and is partially resistant to protease digestion. Although PrPSc is believed to be essential for the pathogenesis and transmission of prion disorders, the mechanism by which PrPSc deposits cause neurodegeneration is unclear. It has been proposed that in some cases of prion disorders, a transmembrane form of PrP, termed CtmPrP may be the mediator of neurodegenerative changes rather than PrPSc per se. In order to understand the underlying cellular processes by which PrPSc mediates neurodegeneration, we have investigated the mechanism of neurotoxicity by a beta-sheet rich peptide of PrP in a cell model. We show that exposure of human neuronal cell lines NT-2 and M17 to the prion peptide 106-126 (PrP106-126) catalyzes the aggregation of endogenous cellular prion protein (PrPC) to an amyloidogenic form that shares several characteristics with PrPSc. Intracellular accumulation of these PrPSc-like forms upregulates the synthesis of CtmPrP, which is proteolytically cleaved in the endoplasmic reticulum and the truncated C-terminal fragment is transported to the cell surface. In addition, we have isolated mutant NT-2 and neuroblastoma cells that are resistant to toxicity by PrP106-126 to facilitate further characterization of the biochemical pathways of PrP106-126 neurotoxicity. The PrP106-126-resistant phenotype of these cells could result from aberrant binding or internalization of the peptide, or due to an abnormality in the downstream pathway(s) of neuronal toxicity. Thus, our data suggest that PrPSc aggregation occurs by a process of 'nucleation' on a pre-existing 'seed' of PrP. Furthermore, the PrP106-126-resistant cells reported here will provide a unique opportunity for identifying the cellular and biochemical pathways that mediate neurotoxicity by PrPSc.

Ghafourifar P, Sen CKMitochondrial nitric oxide synthase. Front Biosci 12: 1072-1078

February 2007

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51 Reads

Nitric oxide (NO) regulates several cellular functions via reversible regulation of mitochondrial respiration. Nitric oxide also reacts with mitochondrial superoxide anion to produce the potent oxidative species peroxynitrite that irreversibly hinders mitochondrial activities. Recent findings demonstrating that mitochondria produce NO via mitochondrial NO synthase (mtNOS) has intrigued several laboratories revealing crucial roles for mtNOS-derived NO and peroxynitrite in regulating the functions of mitochondria, cells and organs. The present article reviews the current understanding of the interactions between mitochondria, and NO and peroxynitrite.

Figure 1. Grand mean difference waveforms elicited from adults and children in the ignore and attend conditions obtained by subtracting the ERPs elicited by the standard frequency tone (1000 Hz) from the ERPs elicited by the easy (1500 Hz) and hard (1050 Hz) frequency deviant tones. The solid lines are the waveforms at Fz and the dashed lines are the waveforms at the mastoids. Stimuli were presented at time zero. (modified from Gomes, et al., submitted) 
The development of auditory attention in children. Frontiers in Bioscience, 5, 108-120
  • Literature Review
  • Full-text available

February 2000

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2,323 Reads

In this paper we review the development of four components of auditory attention: arousal, orienting, selective attention and sustained attention. We focus especially on the processes responsible for the selection of specific stimuli for further processing because these are essential for learning and development. Although much work still needs to be done, there is evidence of developmental change in some of the components of attention, especially early in infancy. Later developmental improvements seem to be primarily attributable to higher cognitive processes, such as motivation, strategy development and implementation, and voluntary direction and regulation of attention.
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Table 1 . Effect of age on the growth of transplantable tumors in rodents 
Anisimov VNEffect of host age on tumor growth rate in rodents. Front Biosci 11: 412-422

February 2006

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205 Reads

There is growing evidence that accumulation of senescent cells in tissues may promote cancer in aged organisms. It is also generally believed that the growth of malignant tumors is slower and metastasis occurs less frequently in elderly than in young individuals. Here, experimental data on the effect of aging on the growth of transplanted tumors are discussed. No uniform pattern of behavior of tumor cells in old organisms can be observed. While some tumors grow faster in young compared to old animals, others grow slowly. This difference appears to depend on tumor and host factors. There is evidence that the implantation of metastatic tumor cells depends on humoral host factors, whereas the growth rate of metastasis mainly depends on local (microenvironmental) host factors. Age-associated changes in both humoral and local host factors are critical to the behavior and progression of transplanted tumors in the old host.

Table 1 . Factors regulating CRH-BP expression in in vivo and in vitro models
Figure 2. Alignment of CRH-BP amino acid sequences from multiple vertebrate and invertebrate species with the human CRHBP sequence. Sequences important for contacting CRH are boxed (Arg 23 and Arg 36 ). Cysteine residues that are involved in 
Figure 3. Potential functional roles for CRH-BP. A. CRH-BP may inhibit CRH binding to the CRH-R and downstream signaling activity by binding, sequestering and/or degrading CRH. B. CRH-BP may potentiate CRH activity by extending the half-life of CRH or delivering CRH to its receptor, thereby increasing downstream CRH activated signaling. C. CRH-BP may have CRH-and/or CRH-R-independent signaling roles. transmembrane domains or a glycosylphosphatidylinositol anchor (48).
Westphal NJ, Seasholtz AF. CRH-BP: the regulation and function of a phylogenetically conserved binding protein. Front Biosci 11: 1878-1891

February 2006

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826 Reads

Corticotropin Releasing Hormone-Binding Protein (CRH-BP), a 37 kDa secreted glycoprotein, binds both CRH and urocortin with high affinity and is structurally unrelated to the CRH receptors. CRH-BP orthologues have been identified in multiple invertebrate and vertebrate species. It is strongly conserved throughout evolution, suggesting the maintenance of a structural conformation necessary for biological activity. CRH-BP is an important modulator of CRH activity; it inhibits CRH-induced ACTH secretion from pituitary corticotropes and may exert similar actions at central sites of CRH release. While the function of CRH-BP is thought to be primarily inhibitory, recent studies indicate that novel functional roles may exist in both the brain and pituitary. Regulation of CRH-BP expression by stress and metabolic factors are consistent with in vivo models of altered CRH-BP expression. Positive regulation of pituitary CRH-BP by reproductive hormones suggests that additional interactions between the stress and reproductive axes may exist. While recent research has focused on the evolutionary conservation, expanded sites of expression, regulation and in vivo function of CRH-BP, a more complete understanding of the central and peripheral functions of CRH-BP and its mechanisms of action will help elucidate its potential role in the etiology or treatment of disorders of CRH dysregulation.

Regulation of Magnesium content during proliferation of mammary epithelial cells (HC-11).

October 2004

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172 Reads

To study the role of Magnesium in the regulation of cell proliferation we characterized the proliferation behaviour of HC-11 mammary epithelial cells that were grown in media containing low to high Mg concentrations. Cells grown under control conditions (0.5 mM Mg in the medium) or in the presence of high (H) Mg (45 mM) displayed similar log-phases and reached confluence in 72h. In the presence of low (L) Mg (0.025 mM) the cells exhibited a reduced growth rate and did not reach confluence at 72h. Intra cellular total Mg increased from 12 to 36h of culture in all cells examined but returned to basal levels in those cells which reached confluence (i.e., control and H-Mg cells). Intra cellular Mg increased independent of mitosis-induced changes of volume and adenine nucleotides pools but correlated with an increased percentage of cells in the S phase and with total nucleic acid contents. These bell-shaped changes of intra cellular Mg were less evident in L-Mg cells, likely due to a combination of low Mg levels in the medium and decreased growth rate. Changes in membrane potential and pH were important factors that contributed to maintaining intra cellular Mg at physiologic levels in the face of increased or decreased availability of extra cellular Mg. H-Mg cells were depolarised and more acidic than control cells; conversely, L-Mg cells showed a pattern of hyperpolarization and alkalinization. These results lend support to the concept that Mg may be involved in regulating cell proliferation, and show that cells maintain adequate levels of intra cellular Mg, and hence their proliferation potential, even under conditions of extreme changes of extra cellular Mg.

Figure 1. Fluorescence microscopy showing the distribution of microtubules in mouse macrophages during FcgR-mediated phagocytosis of IgG-opsonized erythrocytes (IgG-Es). Macrophages were fed with IgG-Es for 10 min, fixed and stained with rhodamine-phalloidin for the actin filaments, immunostained for tubulin, and stained with DAPI for the nuclei. (A) Rhodamine-phalloidin staining shows actin-filament assembly at the site of IgGEs binding. (B) Microtubules emanate from the microtubule-organizing center located in the perinuclear region. Some microtubules extend to the vicinity of the actin-rich phagocytic cups (arrows). (C) Corresponding phase-contrast image merged with the DAPI staining image. Bar: 10 microns
Figure 2. Scheme of microtubule-mediated transport in phagosome formation and phagosome maturation. Green lines indicate microtubules. Black arrows indicate the direction of transport. Red arrows indicate 'kiss-and-run' transient fusion. Biosynthetic transport route from Golgi apparatus is not shown. EE: early endosome; LE: late endosome; P 1 : phagosome acquiring early endosomal properties; P 2 : phagosome acquiring late endosomal properties; PL: phagolysosome; L: lysosome; TL: tubular lysosome; ER: endoplasmic reticulum; MTOC: microtubule-organizing center
Figure 3 . Scanning EM comparison of the morphology of phagocytic cups formed in the presence of various inhibitors. (A) A phagocytic cup engulfing an IgG-E in a control macrophage incubated with IgG-Es for 7 min. Note that the cylindrical phagocytic cup closely follows the surface of IgG-E. (B) Many phagocytic cups remained unclosed in wortmannin-treated cells even after a 30-min incubation with IgG-Es. The phagocytic cups are shown to be tightly fitted around the IgG-Es, just like the phagocytic cups of the control cells. (C) In ML-7 treated cells, phagocytic cup formation was not inhibited, but the morphology of the cups was remarkably different from that in the control or PI3-kinase-inhibited cells. Note that the pseudopod extends away from the surface of the IgG-E. (D) Cytochalasin D completely inhibited phagocytic cup formation, suggesting that pseudopod extension is dependent on actin polymerization. Reproduced from (4). Bars: 5 microns. 
Araki, N. Role of microtubules and myosins in Fc receptor-mediated phagocytosis. Front. Biosci. 11, 1479-1490

February 2006

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603 Reads

Microtubules serve as tracks for vesicular traffic in both phagosome formation and phagosome maturation. In the process of phagosome formation, endomembrane vesicles are delivered to the membrane of the forming phagosomes to supply membrane. This localized endomembrane delivery, referred to as focal exocytosis, facilitates pseudopod extension for the purpose of engulfing large particles. The microtubule-based transport system is the most likely candidate for such targeted vesicle trafficking to the forming phagosomes. During their maturation process, phagosomes interact with early and late endosomes and finally fuse with lysosomes. Although phagosomal membrane fusion with other membranous compartments does not require microtubules, bi-directional transport and positioning of the two organelles on microtubules are necessary for their close positioning and subsequent membrane fusion. Microtubules are also responsible for vesicle trafficking along the antigen presentation pathway for phagocytosed materials. Some classes of myosin are involved in diverse processes of Fc gamma receptor (FcgR)-mediated phagocytosis as force generators and actin-based transport motors. The role of myosin II in phagocytic cup squeezing is complementary to the classical zipper closure model. Myosin Ic and myosin X seem to be key players in extending and closing phagocytic-cup pseudopod. Other classes of myosin may also be involved in phagosomal movement. Myosin V may control short-range phagosome movement and relay phagosomes to the long-range linear transport system using microtubules.

Figure 1. HVJ (hemagglutinating virus of Japan)-liposome and HVJ-envelope. HVJ-liposome: (a, b) HVJ is inactivated by UV. (c, d) Plasmid DNA is incorporated into liposome by vortex-ultrasonication. (e) The liposome is fused with UV-inactivated HVJ. HVJ-envelope: (f, g) HVJ is inactivated by UV. (h) The membrane permeability of HVJ is increased by detergent and the plasmid DNA is incorporated into inactivated HVJ. 
Table 1 . VEGF or HGF as potential therapeutic agents for neurological disorders
Shimamura M, Sato N, Yoshimura S, Kaneda Y, Morishita RHVJ-based non-viral gene transfer method: successful gene therapy using HGF and VEGF genes in experimental ischemia. Front Biosci 11:753-759

February 2006

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407 Reads

VEGF and HGF are pleiotropic factors that regulate cell growth, cell motility, and morphogenesis of various types of cells. The receptors of these growth factors are expressed in neurons and endothelial cells, and are identified as neurotrophic, neuroprotective, and angiogenic factors. Indeed, gene therapy using viral vectors encoding the VEGF or HGF gene has been reported to be effective for preventing the expansion of ischemic injury. However, the safety issue of viral vectors is a major problem in clinical application. To overcome this problem, we have developed an HVJ-based non-viral vector, which achieves high-efficiency transfection rates of viral vectors with the safety of liposomes. This review discusses the feasibility of gene therapy using an HVJ-based non-viral vector containing the VEGF or HGF gene for cerebral ischemia.

[Frontiers in Bioscience 11, 2538-2553, September 1, 2006]

February 2006

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44 Reads

The replacement of a "cartilage model" by definitive bone is characterized by a series of localized excavations of the cartilage which are eventually followed by bone deposition. Each excavation requires lysis of cartilage components (defined here as the breakdown of a peptide bond) and their eventual resorption (defined here as microscopical visible cartilage loss). More precisely we have proposed that the lysis is affected by proteases capable of breaking down the main proteoglycan "aggrecan" and the main fibril element, "type II collagen". Four approaches combining biochemical, immunologic and microscopic techniques have been adapted to test this hypothesis. Each is applied to the rat tibial head's "cartilage model" where proteases have been shown to be major contributors to secondary ossification center formation. The approaches have been found both effective and distinct as cartilage resorbing enzymes have not only been identified but also detected in situ before and after activation. Achieved overall is an understanding of when, where and how specified proteases contribute to tissue component lyses. While the focus resides on the in situ proteolysis of cartilage, three of the approaches could be translated without change to other tissues, whereas one may require tissue specific adjustments before use.

1 Graduate School of Agricultural Science, 2 Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan, 3 Division of Nephrology and Hypertension, Department of Medicine, Texas A & M University college of Medicine/ Scott & White hospital, Temple, Texas 76504, 4 Keio University School of Medicine, Tokyo 160-8582, Japan, 5 Department of Biochemistry School of Medicine, Vanderbilt University, Nashville 37235, TN

February 2007

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112 Reads

A role of the "handle" region in the prorenin prosegment sequence was investigated to demonstrate the crucial non-proteolytic activation of prorenin by binding to the recombinant (pro)renin receptor on the COS-7 cell membrane. The plasmid DNA containing either rat or human (pro)renin receptor was transfected into the COS-7 cells. The highest amount of receptor was observed on the COS-7 cell membrane after 18 h transfection. Of the total rat and human prorenin, 90% and 50% were bound to each of the respective receptors, respectively. The Kd values were 0.89 and 1.8 nM, respectively. Rat prorenin was activated non-proteolytically by the receptor. The Km was determined 1.0 microM when sheep angiotensinogen was used as the substrate. Human prorenin was also activated by the receptor. The Km was 0.71 microM. Additionally, decapeptides (10P-19P) known as "decoy" peptide and pentapeptides (11P-15P) named "handle" region peptide, were observed to inhibit the binding of both prorenins to receptors, respectively. The Ki were similar around 7 nM for both the peptides. Other two region peptides in the prosegment did not interfere the binding. These results show that the "handle" region probably plays a crucial role in prorenin binding to the receptor and in its enzymic activity by non-proteolytic activation.

Transcriptional regulation of the 11p15 mucin genes. Towards new biological tools in human therapy, in inflammatory diseases and cancer?

November 2001

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358 Reads

Mucin production and secretion by specialized epithelial cells is a common mechanism used by mammals to protect the underlying mucosae against various injuries (pollutants, pathogens, pH). The expression of mucin genes is cell- and tissue-specific but is submitted to variations during cell differentiation, inflammatory process, and is altered during carcinogenesis. The molecular mechanisms responsible for the control of mucin transcription and expression are beginning to be understood as mucin gene promoters and regulatory regions are characterized. The four gel-forming mucin genes, MUC2-MUC5AC-MUC5B-MUC6, are clustered on the p15 arm of chromosome 11. Common regulatory mechanisms (PKA, PKC, PKG and Ca2+ signaling, Sp1/Sp3) may account for the capability of mucous-secreting cells to express several mucin genes simultaneously. In response to an insult or during carcinogenesis, the normal pattern of expression is altered and results from specific answers of the cell by activating different intracellular signaling pathways. 11p15 mucin genes are regulated at the transcriptional level by pro-inflammatory cytokines (IL-1beta, IL-6, TNF-alpha), pleiotropic cytokines (IL-4, IL-13, IL-9), bacterial exoproduct (LPS), growth factors (EGF, TGF-alpha), lipid mediator (PAF), retinoids and hormones. To date, the only downstream cascade known to activate mucin gene transcription is the Src/Ras/MAPK/pp90rsk cascade, which leads to the activation of the transcription factor NF-kappaB. Mucin gene transcription is also regulated by ATF-1, CREB and RAR-alpha transcription factors. Finally, repression of mucin transcription in cancer cells is under the control of the epigenetic mechanism of methylation. As transcriptional regulation of mucin genes begins to be unraveled, it becomes clear that many signaling pathways are involved. Our understanding of mucin gene transcriptional regulation, which awaits more data (identification of the signaling cascades and active cis-elements within promoters and introns), will most certainly lead to the use of mucin genes as molecular markers in cancer and molecular tools in human gene therapy, and to the synthesis of new therapeutic agents in inflammatory diseases of the epithelium.

Zhang S, Zhang Q, Zhang JH, Qin XElectro-stimulation of cerebellar fastigial nucleus (FNS) improves axonal regeneration. Front Biosci 13:6999-7007

February 2008

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26 Reads

This study focused on the effect of electro-stimulation of fastigial nucleus on the expression of NgR and on axonal regeneration after focal cerebral ischemia-reperfusion in rats. Cerebral ischemia and reperfusion was induced by nylon monofilament. Ninety-six male SD rats were randomly divided into sham group and ischemic insult groups at 12 hours, 24 hours, and 1 to 3 weeks after cerebral ischemia-reperfusion. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the changes of NgR mRNA expression. Immunohistochemistry was used to detect the expression of NgR protein and the state of axonal regeneration. Fastigial nucleus stimulation was applied at 2 hours after ischemia for one hour. The results demonstrated that NgR mRNA and protein in the infarcted cortex and hippocampus were significantly increased (p<0.01). The axons were grossly damaged at 24 h after cerebral ischemia-reperfusion when compared to the sham group. Fastigial nucleus stimulation decreased NgR mRNA and protein levels in the infarcted cortex and hippocampus (p<0.01) and improved axonal growth at 24 hours and 2 weeks after ischemia-reperfusion (p<0.05). These results suggest that electrostimulation of fastigial nucleus might provide a new strategy to promote CNS axonal regeneration.

Buratti, E. & Baralle, F. E. Multiple roles of TDP-43 in gene expression, splicing regulation, and human disease. Front. Biosci. 13, 867-878

February 2008

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2,757 Reads

TDP-43 is a RNA/DNA binding protein that structurally resembles a typical hnRNP protein family member and displays a significant specificity for binding the common microsatellite region (GU/GT)n. Initially described as a regulator of HIV-1 gene expression, it has been reported in the past to affect both normal and pathological RNA splicing events. In particular, it has been shown to play a fundamental role in the occurrence of several monosymptomatic/full forms of Cystic Fibrosis caused by pathological skipping of CFTR exon 9 from the mature mRNA. Recently, and in a way probably unrelated to splicing, a hyperphosphorylated form of TDP-43 has also been found to accumulate in the cytoplasm of neuronal cells of patients affected by fronto temporal lobar degenerations. In addition to its role in transcription and splicing regulation, a growing body of evidence indirectly suggests that TDP-43 may be involved in other cellular processes such as microRNA biogenesis, apoptosis, and cell division. The aim of this work is to provide the basic facts about TDP-43 an assessment of the multiple functions ascribed to this protein.

Studying telomeres in a longitudinal population based study. Frontiers in Bioscience, 13(13), 2960-2970

February 2008

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42 Reads

Telomeres, the termini of linear chromosomes, consist of large but variable numbers of DNA oligomer repeats embedded in a nucleoprotein complex. In humans, telomere length (TL) is largely genetically determined but also featured by an age dependent attrition. TL has therefore been put forward as a marker for biological aging and was also reported to be associated with aging diseases such as cardiovascular disease. However it remains unclear whether the biomarker value in a particular disease depends on shorter TL at birth or rather if it's a mere reflection of an accelerated telomere attrition during lifetime, or else, if it is a combination of both. While the importance of telomere attrition is supported by cross-sectional evidence associating shorter telomeres with oxidative stress and inflammation, longitudinal studies are required to accurately assess telomere attrition and its presumed link with accelerated aging. In this review we present different models for the biomarker value of TL and discuss the theoretical and methodological considerations of studying TL in a longitudinal population study with a special emphasis on cardiovascular disease.

Kapadia R, Yi JH, Vemuganti RMechanisms of anti-inflammatory and neuroprotective actions of PPAR-gamma agonists. Front Biosci 13:1813-1826

February 2008

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80 Reads

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors of the nuclear hormone receptor superfamily. The 3 PPAR isoforms (alpha, delta/beta and gamma) are known to control many physiological functions including glucose absorption, lipid balance, and cell growth and differentiation. Of interest, PPAR-gamma activation was recently shown to mitigate the inflammation associated with chronic and acute neurological insults. Particular attention was paid to test the therapeutic potential of PPAR agonists in acute conditions like stroke, spinal cord injury (SCI) and traumatic brain injury (TBI), in which massive inflammation plays a detrimental role. While 15d-prostaglandin J2 (15d PGJ2) is the natural ligand of PPAR-gamma, the thiazolidinediones (TZDs) are potent exogenous agonists. Due to their insulin-sensitizing properties, 2 TZDs rosiglitazone and pioglitazone are currently FDA-approved for type-2 diabetes treatment. Recent studies from our laboratory and other groups have shown that TZDs induce significant neuroprotection in animal models of focal ischemia and SCI by multiple mechanisms. The beneficial actions of TZDs were observed to be both PPAR-gamma-dependent as well as -independent. The major mechanism of TZD-induced neuroprotection seems to be prevention of microglial activation and inflammatory cytokine and chemokine expression. TZDs were also shown to prevent the activation of pro-inflammatory transcription factors at the same time promoting the anti-oxidant mechanisms in the injured CNS. This review article discusses the multiple mechanisms of TZD-induced neuroprotection in various animal models of CNS injury with an emphasis on stroke.

Subcellular proteomics in neuroscience, Front Biosci 13, 4416-4425

February 2008

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16 Reads

The brain is the most complex and dynamically organized organ of the human body, with a high degree of computation capability enabling the execution of a wide spectrum of physiological processes and behaviors. In the past decades a large number of genomics studies have been undertaken to investigate brain function and brain disorders, but despite these efforts many of the underlying molecular mechanisms still remain largely unknown. The implementation of mass spectrometry based quantitative proteomics in recent years enabled to tap into condition-specific protein trafficking and protein interaction that are the key to organelle proteome (dys)function. The technology for neuroproteomics is still evolving; currently there are no standardized protocols. In this review we describe the most commonly used methods to prepare brain subcellular fractions suitable for proteomics analysis, and highlight the various approaches for quantitative neuroproteomics.

Figure 1. UV toxicity on NPC. Effects of long spectrum UV on E15 SVZ-derived NPC survival. Irradiation was conducted immediately following the 'Before' cell count, cells were then returned to the incubator for 24 hrs followed by the 'After' cell count. Percentages are relative to the 'Before' count in each condition and demonstrate that proliferation was retained in NPC following all UV conditions except the most extreme (26 mW/cm 2 for 3 min). Error bars are standard error of the mean (n=3). 
Figure 2. Effects of Irgacure ® 2959 on NPC. NPC cultures were exposed to UV in the presence of Irgacure ® 2959 photoinitiator. Blue box: Is a control cell count prior to UV exposure. Purple box: Is the control condition at 24 hrs. The other conditions are detailed in the legend for which cell counts were obtained 24 hrs post UV exposure. 
Figure 3. Biomimetic ECM. The close up view displays the key components that can be incorporated into biomimetic material scaffolds; bound peptide sequences, soluble or bound growth factors and/or other cytokines, degradable component (e.g. gelatin), and a stable backbone (photo-crosslinked PEG). 
Figure 4. E15 SVZ-derived NPC adhesion and proliferation on peptide-engrafted surfaces. PHSRNG 6 RGD supported significantly higher (*) adhesion and proliferation over all other peptides (p>0.05), except IKVAV. The laminin condition reached confluency by day 7. The decrease in cell counts at day 14 was due to clusters of NPC disengaging from the surface prior to counting. This indicates that NPC adhered less tightly to peptideengrafted surfaces than to laminin-coated coverslips. NPC on laminin-coated coverslips reached confluency by day 7. 
Potter W, Kalil RE, Kao WJBiomimetic material systems for neural progenitor cell-based therapy. Front Biosci 13:806-821

February 2008

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263 Reads

Reconstruction and regeneration of the central nervous system (CNS) following injury is a formidable task. However, cell replacement with transplanted neural progenitor cells (NPC) is a promising technique that has resulted in various levels of functional recovery in animals that had experienced an experimental injury of the brain or spinal cord. Unfortunately, CNS injury often leads to significant tissue damage and loss, limiting the survival and integration of transplanted NPC. In response, researchers have developed many biomaterial substrates that have been used to culture, transplant, and influence the differentiation and integration of transplanted NPC. Biomaterial scaffolds are a three-dimensional lattice that can be engineered to support NPC in vitro as well as serving as a temporary extracellular matrix (ECM) after transplantation. Scaffold modification with bioactive components, such as proteins, adhesive peptide sequences, and growth factors, allow researchers to modulate NPC responses as well as the local environment of the transplantation site. Biomimetic approaches also can include materials that recapitulate the structural dimensions of the ECM, namely self-assembling nanofibers. These materials can be useful for altering the tissue microenvironment by reducing inflammation and glial scarring, which may further enhance NPC survival and integration into functional neural circuitry. This review describes various biomaterial constructs, with a focus on biomimetic systems that have been used in modulating NPC behavior in culture and/or in transplanting NPC to the CNS.

Fujiwara, T, Urata, Y and Tanaka, N. Diagnostic and therapeutic application of telomerase-specific oncolytic adenoviral agents. Front Biosci 13: 1881-1886

February 2008

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37 Reads

Replication-selective tumor-specific viruses present a novel approach for treatment of neoplastic disease. These vectors are designed to induce virus-mediated lysis of tumor cells after selective viral propagation within the tumor. Telomerase activation is considered to be a critical step in carcinogenesis and its activity correlates closely with human telomerase reverse transcriptase (hTERT) expression. Since only tumor cells that express telomerase activity would activate this promoter, the hTERT proximal promoter allows for preferential expression of viral genes in tumor cells, leading to selective viral replication. We constructed an attenuated adenovirus 5 vector (Telomelysin, OBP-301), in which the hTERT promoter element drives expression of E1A and E1B genes linked with an internal ribosome entry site (IRES). Telomelysin replicated efficiently and induced marked cell killing in a panel of human cancer cell lines, whereas replication as well as cytotoxicity was highly attenuated in normal human cells lacking telomerase activity. We further modified the E3 region of OBP-301 to contain green fluorescent protein (GFP) gene for monitoring viral replication (TelomeScan, OBP-401). When TelomeScan was intratumorally injected into human tumors orthotopically implanted into the rectum in mice, para-aortic lymph node metastasis could be visualized at laparotomy under a three-chip color cooled charged-coupled device camera. Our results indicate that TelomeScan causes viral spread into the regional lymphatic area and selectively replicates in neoplastic lesions, resulting in GFP expression in metastatic lymph nodes. This article reviews recent highlights in this rapidly evolving field: cancer therapeutic and cancer diagnostic approaches using the telomerase-specific oncolytic adenoviruses.

Lan, H. Y. SMAD7 as a therapeutic agent for chronic kidney diseases. Front. Biosci. 13, 4984-4992

February 2008

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43 Reads

Increasing evidence shows that transforming growth factor-beta TGF-beta1 (TGF-beta1) is upregulated and plays a diverse role in renal fibrosis by stimulating extracellular matrix (ECM) production, while inhibiting renal inflammation. Recent studies have identified that TGF-beta1, once activated, signals through its downstream signaling pathway to exert its biological effects. It is now well accepted that TGF-beta regulates fibrosis positively by receptor-associated Smads including Smad2 and Smad3, but negatively by an inhibitory Smad, called Smad7. We and other investigators have shown that gene transfer of Smad7 is able to inhibit renal fibrosis in a number of experimental models of chronic kidney diseases, including obstructive nephropathy, remnant kidney disease, and autoimmune crescentic glomerulonephritis. Blockade of Smad2/3 activation is a major mechanism by which overexpression of Smad7 inhibits renal scarring. Furthermore, our recent findings also demonstrate that Smad7 plays a critical role in anti-inflammation in chronic kidney diseases by blocking the NF.kappaB-dependent inflammatory pathway. Thus, Smad7 has a unique role in both anti-renal fibrosis and inflammation. These findings also indicate that targeting the TGF-beta/Smad signaling pathway by overexpressing Smad7 may provide a novel, specific, and effective therapy for chronic kidney diseases.

Pang CY, Ma YS, Wei YUMtDNA mutations, functional decline and turnover of mitochondria in aging. Front Biosci 13:3661-3675

February 2008

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44 Reads

Aging is a complex biological process that involves gradual function deterioration in various tissues and organs of an individual. Mitochondrial function decline can lead to cellular overproduction of reactive oxygen species (ROS) and increase in oxidative damage to biological molecules in the aging process. We have hypothesized that increased production of ROS by the mitochondria in affected tissues in patients with mitochondrial diseases and elderly subject results in increased oxidative stress and oxidative damage. Due to the similarity of human aging process to diseases related to bioenergetic function decline and mitochondrial DNA (mtDNA) alterations, aging is sometimes viewed as a "chronic" version of such diseases. Recent studies have also established that the expression profiles of several clusters of genes are altered, oxidative modification of proteins are increased and their turnover are decreased in tissues of old human subjects and animals. Accumulating evidence has suggested that mtDNA mutations, oxidative stress, defective disposal of dysfunctional proteins and a slower turnover of mitochondria are associated with aging.

Resnick, A. C. & Saiardi, A. Inositol polyphosphate multikinase: metabolic architect of nuclear inositides. Front. Biosci. 13, 856-866

February 2008

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26 Reads

The inositides are key cellular second messengers with well established roles in signal transduction pathways initiated by cell surface receptor activation. The recent identification of an evolutionarily conserved nuclear signaling pathway for higher inositol polyphosphates has defined a new signaling paradigm for this diverse class of molecules whose biosynthesis and regulation is mediated by what are likely some of the earliest ancestors of the inositide kinase families. Inositol polyphosphate multikinase (IPMK) represents the most catalytically diverse member of this family with critical roles in nuclear functions including mRNA export, transcriptional regulation, and chromatin remodeling.

Regulation of matrix metalloproteinase-13 and tissue inhibitor of matrix metalloproteinase-1 gene expression by WNT3A and bone morphogenetic protein-2 in osteoblastic differentiation

February 2006

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44 Reads

During bone remodeling, degradation of skeletal connective tissue is regulated, at least in part, by the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinase (TIMPs), their natural inhibitors. Recently, the Wnt signaling pathway has been demonstrated to play a crucial role in the regulation of bone formation. Here, we investigated a potential role for Wnt signaling and functional cross-talk with bone morphogenetic protein (BMP)-2 in mRNA expression of MMPs, TIMPs and bone matrix proteins in pluripotent C2C12 cells. To assess the functional contribution of Wnt signaling, we have generated C2C12 cell lines stably over-expressing Wnt3a or Wnt5a, and then treated these cells with BMP-2 for 24 h. In these cultures, MMP-13 mRNA expression was induced by BMP-2 in Wnt3a over-expressing C2C12 (Wnt3a-C2C12) cells but not in either Wnt5a over-expressing C2C12 (Wnt5a-C2C12) cells or vehicle-transfected C2C12 cells. MMP-13 mRNA was induced in these cells by addition of BMP-2 for 12 h and the enhancement lasted up to 48 h. These effects were observed in a dose-dependent manner. Enzymatic activity of MMP-13 also induced in Wnt3a-C2C12 cells by addition of BMP-2. However, membrane type-1 matrix metalloproteinase (MT1-MMP) and MMP-2 mRNA expression was not affected by either Wnt3a or BMP-2. In contrast, TIMP-1 mRNA expression was suppressed by BMP-2 in Wnt3a-C2C12 cells but not in Wnt5a-C2C12 cells. Our results show that expression of MMP-13 and TIMP-1 is regulated by Wnt signaling combined with BMP-2 in osteoblastic differentiation, and this signaling may in part mediate MMP-13 and TIMP-1 production during bone formation and/or remodeling.

Figure 3. Schematic representation of the FCP1 protein phosphatase. The FCPH (FCP1 Homology domain), BRCT and the two RAP74 domains are indicated. 
Majello, B. & Napolitano, G. Control of RNA polymerase II activity by dedicated CTD kinases and phosphatases. Front. Biosci. 6, D1358-1368
The elongation phase of eukaryotic transcription by RNA polymerase II (RNAPII) is an important target for regulation of gene expression. An interplay of positive and negative elongation factors determines the elongation activity of RNAPII in different promoters. The phosphorylation status of the carboxyl-terminal-domain (CTD) of the larger subunit of RNAPII appears to be the regulatory focus of different factors regulating mRNA processivity. The emerging model of the transcription cycle proposes that the phosphorylation state of the CTD is dynamic during elongation with different forms predominating at different stages of transcription. Shortly after initiation RNA polymerase II comes under the control of negative elongation factors and enters abortive elongation. Escape from the action of these negative controls requires the action of at least one positive elongation factor identified in the P-TEFb complex composed of the Cyclin-Dependent Kinase CDK9 and its regulatory subunit cyclin T. Finally, the requirement of CTD phosphatase activity, identified in the FCP1 protein, has been invoked as necessary to recycle the hypophosphorylated form of the RNA polymerase II competent to reinitiate the transcription cycle.

Ueda, H. & Ueda, M. Mechanisms underlying morphine analgesic tolerance and dependence. Front. Biosci. 14, 5260-5272

February 2009

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111 Reads

The mechanisms underlying opioid tolerance are not fully understood, but appear to be comprised of two types of plasticity or counter-adaptation, at the cellular level and through neuronal circuits. Current studies mostly emphasize the cellular adaptation mechanisms, which include altered gene expression and receptor desensitization due to phosphorylation and endocytosis. However, the mechanisms underlying opioid tolerance and dependence are not always explained by cellular adaptation mechanisms alone. This review focuses on the plasticity in neuronal circuits achieved through an enhancement of synaptic activities between glutamate and NMDA receptor due to up-regulation of receptor and racemase to produce D-serine, an allosteric NMDA receptor agonist, and down-regulation of glutamate transporter, all which contribute to the counterbalance of opioid actions or anti-opioid mechanisms underlying opioid tolerance. This anti-opioid system is supposed to be also augmented by altered expression of key molecules regulating through neuron-glial networks. This review also introduces a new approach using in vivo electroporation to identify the brain loci responsible for morphine tolerance and dependence.

Figure 1. An integrated view of the shared neurobiological underpinnings of major depression (MDD), fibromyalgia (FM) and neuropathic pain (NeP) . 
Figure 2. Cortical and subcortical areas involved in voluntary and automatic regulation of mood and the stress response. Reprinted with permission from (134). 
Figure 3. Mood disorders, fibromyalgia (FM) and neuropathic pain (NeP) may have shared systemic consequences. Compromised homeostatic function of prefrontal cortical-limbic circuitry in MDD, FM and NeP appears to disrupt autonomic, neuroendocrine and neuroimmune regulation. Stress, pain and depression lead to excessive and untimely release of corticotropin- releasing hormone (CRH), adenocorticotropic hormone (ACTH) and glucocorticoids. Sympathetic over-activity, combined with diminished parasympathetic tone, contributes to immune activation and release of proinflammatory cytokines (e.g. TNF-alpha, IL-1, IL-6) from macrophages and other immune cells. Inflammatory cytokines further interfere with monoaminergic and neurotrophic signaling. They may also down-regulate central glucocorticoid receptor sensitivity, leading to further disruption of feedback control of the hypothalamic-pituitary-adrenal (HPA) axis and the immune system. In depression and pain states, disturbances of serotonin (5HT), norepinephrine (NE) and dopamine (DA) transmission may impair regulatory feedback loops that turn off the stress response, with a resultant compromise in the function of descending pain modulatory pathways. Elevated mediators of the inflammatory response, combined with excessive sympathetic tone may further impact dorsal column processing of pain signals by contributing to activation of microglia and astroglia. Activated microglia exchange signals with astrocytes and nociceptive neurons, amplifying pain-related transmission of glutamate (Glu), substance P (SP), adenosine triphosphate (ATP), brain-derived neurotrophic factor (BDNF), pro-inflammatory cytokines (IL-1, IL-6, IL-8, TNF-alpha , nitrogen oxide (NO) and prostaglandins (PGs). PVN= Paraventricular nucleus of hypothalamus; IL = interleukin; TNF-alpha = Tumor necrosis factor- alpha; Ach=acetyl choline 
Figure 4. Microglia are the primary recipients of peripheral inflammatory signals as they reach the brain. Activated microglia initiate an inflammatory cascade by releasing cytokines, chemokines, prostaglandins and reactive nitrogen and oxygen species (RNS and ROS, respectively). Bi-directional exchanges between microglia and astroglia amplify inflammatory signals within the central nervous system (CNS). Cytokines including interleukin (IL)-1, IL-6, tumor necrosis (TNF)-alpha and interferon (IFN)- gamma induce indoleamine 2,3 dioxygenase (IDO), the enzyme responsible for degrading tryptophan, the primary precursor of serotonin (5-HT), into kynurenine, which is eventually metabolized into quinolinic acid (QUIN), a potent NMDA agonist and stimulator of glutamate (Glu) release. Multiple astrocytic functions are compromised due to the excessive exposure to cytokines, prostaglandins, QUIN and RNS/ROS, ultimately leading to downregulation of glutamate transporters, impaired glutamate reuptake, excessive glutamate release and compromised synthesis and release of neurotrophic factors. Oligodendroglia suffer damage due to toxic overexposure to cytokines such as TNF-alpha, and diminished neurotrophic support, both of which promote apoptosis and demyelination. Copious amounts of glutamate are released from astrocytes in the vicinity of extrasynaptic NMDA receptors, whose activation leads to inhibition of BDNF synthesis. Excessive NMDA activation, caused by QUIN and D-serine, is compounded by diminished glutamate reuptake by astrocytes and oligodendroglia. NMDA-mediated excitotoxicity, combined with a consequent decline in neurotrophic support, and an increase in oxidative stress, synergistically disrupts neural plasticity and induces apoptosis. 
Maletic V, Raison CL. Neurobiology of depression, fibromyalgia and neuropathic pain. Front Biosci 14: 5291-5338

February 2009

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7,047 Reads

This article synthesizes recent data suggesting that the high rates of comorbidity observed between major depression, fibromyalgia and neuropathic pain likely result from the fact that these disorders share multiple biological and environmental underpinnings. This perspective suggests that these biologically complex conditions result from similar genetic vulnerabilities interacting with environmental adversity. Shared genetic determinants include poorly functional alleles regulating monoaminergic, glutamatergic, neurotrophic, opioid and inflammatory cytokine signaling. Chief among environmental risk factors are psychosocial stress and illness, both of which promote, in vulnerable individuals, relative resistance to glucocorticoids, increased sympathetic/decreased parasympathetic activity and increased production and release of proinflamnmatory mediators. Dysregulation of stress/inflammatory pathways promotes alterations in brain circuitry that modulates mood, pain and the stress response. Over time, these functional changes likely promote disruptions in neurotrophic support and disturbances of glia-neuronal communication. These changes, in turn, have been associated with the related processes of central sensitization in pain disorders and "kindling" in depression, both of which may account for the progressive and self-perpetuating nature of these disorders, especially when inadequately treated.

Haber SN, Brucker JL. Cognitive and limbic circuits that are affected by deep brain stimulation. Front Biosci 14: 1823-1834

February 2009

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34 Reads

Several lines of evidence indicate that the neural network that underlies the pathophysiology of obsessive-compulsive disorder and depression centers on the prefronto-basal ganglia system. Particularly involved are anterior cingulate cortex, the orbital prefrontal cortex, the ventral striatum, and parts of the thalamus. Additional integral parts of the network include, the amygdala, the midbrain dopamine cells and the serotonergic neurons. Collectively, these brain regions are involved in various aspects of reward-based learning and good decision-making skills. They are also associated with sadness and depression, pathological risk-taking, addictive behaviors, and obsessive-compulsive disorder. Two of the most successful deep brain stimulation targets for obsessive-compulsive disorder and depression are centered in white matter tracts. These targets were chosen for their central location and ability to capture specific ascending and descending connections, with a particular focus on fibers connecting the subgenual anterior cingulate and orbital cortex with the basal ganglia, thalamus, and amygdala. As more knowledge is obtained concerning the details of these connections, more precise targets may be possible.

Electrochemical activation of glucose oxidase with a 140-fold enhancement in intramolecular electron transfer rate constant

February 2005

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164 Reads

In this work, we describe the electrochemical activation of glucose oxidase (GOx) via covalent attachment of a novel redox mediator, Os(bpy)2(API)Cl (bpy = 2,2'-bipyridine, API = 3-aminopropylimidazole), to the peptide backbone of GOx targeting at aspartate and glutamate residues. Cyclic voltammetry showed a pair of well-defined voltammetric peaks centered at 0.11 V for the activated enzyme. Os(bpy)2(API)Cl promotes direct oxidation of FADH2 centers in GOx without the need of any mediating agents in solution. Amperometric tests in glucose solution revealed that the GOx retains its enzymatic activity toward the oxidation of glucose. An intramolecular electron transfer rate constant of 1.0x10(5) s(-1) was obtained for the activated GOx, compared with the rate constant of 7.0x10(2) s(-1) of the natural GOx-oxygen system, making this an amenable system for biosensor applications. Attempts were made in utilizing the activated GOx as an electrochemical tag in nucleic acid assay.

MiR-143 is critical for the formation of primordial follicles in mice

January 2013

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108 Reads

Although microRNAs (miRNAs) have been implicated in fine-tuning gene networks, the roles of mmu-mir-143 (miR-143) in mammalian ovary development have not been studied in vitro. We investigated the expression and function of miR-143 in the mouse ovary during primordial follicle formation. Real-time polymerase chain reaction analysis showed that miR-143 expression increased during primordial follicle formation from 15.5 days post-coitus to 4 days post-partum. miR-143 was located in pregranulosa cells by in situ hybridization. To study the function of miR-143 in primordial follicle formation we established an electroporation transfection model in vitro that allowed miR-143 expression to be efficiently upregulated and inhibited in cultured ovaries. Further studies showed that miR-143 inhibited the formation of primordial follicles by suppressing pregranulosa cell proliferation and downregulating the expression of genes related to the cell cycle. These findings suggest that miR-143 is critical for the formation of primordial follicles and regulates ovarian development and function.

Organization and expression of the human serpin gene cluster at 14q32.1

February 2005

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53 Reads

The serpins are a superfamily of gene sequences that have been conserved through evolution. These genes encode protein products that perform a variety of functions in vivo, and their regulation differs among different cell types. About one-third of the serpin genes in the human genome are located at 14q32.1, and the serpin genes in this ~370 kb region are organized into discrete proximal, central, and distal subclusters of four, three, and four genes each. In this report we discuss the genomic organization of the 14q32.1 serpin gene cluster, and we summarize what is known about the regulation of each serpin gene in this region. An approach for studying locus-wide regulation of chromosomal serpin genes in situ is also described. Using this approach, specific mutations in the proximal serpin subcluster were prepared by homologous recombination. These mutant alleles define a serpin locus control region that regulates gene activity and chromatin structure of the entire proximal subcluster. Prospects for further analyses of this complex genomic domain are discussed.

Role of miR-155 in breast cancer

June 2012

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20 Reads

Breast cancer is the second leading cause of death due to cancer in women. Accumulating evidence shows a correlation between overexpression of miR-155 and breast cancer development. The microRNA (miRNA) encoded by mir-155 is known to be oncogenic in multiple tumors. This review summarizes the signaling pathways that are regulated by miR-155 in breast cancer and discusses therapeutic possibilities related to miR-155.

Cloning, characterization and subcellular localization of a gene encoding a human Ubiquitin-conjugating enzyme (E2) homologous to the Arabidopsis thaliana UBC-16 gene product

February 2006

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34 Reads

Ubiquitin charging and activation of class III E2 enzymes has been directly linked to their nuclear import. It has not been published whether other classes E2s also abide by this mechanism. During the large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a cDNA clone that is 2252 base pair in length, encoding a putative 162 amino acid protein, which shares high homology to Arabidopsis thaliana ubiquitin-conjugating enzyme 16 (Accession number NP_565110, 51% identity and 71% similarity) at protein level. Bioinformatics analysis revealed that the gene is composed of 7 exons, located on human chromosome 8q13-8q21.1, and that the predicted protein of the gene is a class I E2, for only composed of a conserved approximately 150-amino acid catalytic core, ubiquitin-conjugating enzyme E2 domain (UBC domain). In the C-terminal of the UBC domain sequence, there are two nuclear localization signals (NLSs). RT-PCR showed that this gene is ubiquitously expressed in 16 kinds of normal human tissues, but expression level is very low, unless in human heart, brain, liver, and pancreas. The subcellular localizations of the new human Ubiquitin conjugating enzyme E2 and its mutation were also examined, which showed that the nuclear localization of hUBC16 depended on two conditions: It has NLS, and at the same time, has enzyme active site, too, at least in HEK293 cells.

Peterson CW, Ayer DEAn extended Myc network contributes to glucose homeostasis in cancer and diabetes. Front Biosci (Landmark Ed) 16: 2206-2223

June 2011

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82 Reads

The Myc network of transcription factors plays pleiotropic roles in normal and pathological cell function. The canonical Myc network controls how the essential nutrients glucose and glutamine are utilized inside cells. The Myc network carries out this function by upregulating glucose and glutamine transporters and key enzymes in the glycolytic or glutaminolytic pathways. The Myc network also coordinates cellular utilization of glucose and glutamine in biosynthetic pathways by directly regulating mitochondrial mass and activity. We present an argument for the existence of an "extended" Myc network comprised of two related transcription factors MondoA and ChREBP. Both MondoA and ChREBP sense glycolytic flux and are the principal regulators of glucose-dependent transcription in their respective tissues, skeletal muscle and liver. MondoA also senses glutaminolytic flux into the tricarboxylic acid cycle and appears to coordinate the utilization of glucose and glutamine by regulating expression of thioredoxin interacting protein. Current data suggest that the extended Myc network regulates the cellular response to changes in nutrient availability and may be altered in cancer and insulin resistance.

Figure 1. The HPV-16 genome. Early promoter p97 and late promoter p670 are indicated. pAE, early polyA signal and pAL, late polyA signal. Open triangles indicate splice acceptors (3'-splice sites) and filled triangles indicate splice donors (5'-splice sites). Numbers refer to the HPV-16R genome (9). Major mRNA species are shown. Their translation products are indicated to the left.
HPV-16 RNA processing

February 2008

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405 Reads

To understand human papillomavirus type 16 (HPV-16) gene regulation, it is necessary to understand HPV-16 RNA processing. HPV-16 encodes multiple 5'- and 3'-splice sites and two polyadenylation signals pAE and pAL (Figure 1). The major 3'-splice site on the HPV-16 genome (SA3358) is used for generation of E6, E7, E4, L1 and L2 mRNAs. It encodes a suboptimal splice signal but is under control of a strong enhancer that renders SA3358 one of the most efficiently used splice sites on the HPV-16 genome. Thereby SA3358 indirectly blocks HPV-16 late gene expression. The early polyA signal is also under control of the early UTR sequence and multiple RNA elements in the L2 coding region that interact with hnRNP H. The two splice sites SD3632 and SA5639 are used exclusively by late mRNAs and are under control of multiple splicing silencer elements. The silencers at SA5639 are located in the L1 coding region and interact with hnRNP A1. So far, only polypyrimidine tract binding protein (PTB) has been shown to induce late gene expression.

Interleukin-17: A novel inflammatory cytokine that bridges innate and adaptive immunity

February 2008

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93 Reads

Interleukin-17 (IL-17A) is a pro-inflammatory cytokine that is primarily secreted from T lymphocytes, mediators of adaptive immunity. Recently, IL-17 was shown to be the defining cytokine of a new T helper subset termed "Th17." Discovery of the Th17 population was a groundbreaking discovery that has triggered major revisions of the prevailing paradigms in T cell biology. Although produced by T cells, IL-17 promotes expansion and recruitment of innate immune cells such as neutrophils, and also cooperates with TLR ligands, IL-1 beta, and TNF alpha to enhance inflammatory reactions and stimulate production of beta-defensins and other antimicrobial peptides. Its receptor, IL-17RA, is ubiquitously expressed and shares many features with classical innate immune receptors such as shared intracellular tail motifs and convergence on common inflammatory transcription pathways. The role of IL-17 in periodontal disease is still uncertain, since IL-17 has been shown to promote bone destruction in arthritis, but is nonetheless essential to protect the host from pathogens, including periodontopathic organisms. Recent evidence has shown that Th17 cells are more osteoclastogenic than other T helper subsets such as Th1 or Th2. Ablation of IL-17 signaling prior to onset of infection with Porphyromonas gingivalis increases susceptibility to periodontal bone loss, but this finding does not rule out the efficacy of therapeutic inhibition of IL-17 after onset of severe disease. IL-17 sits at the center of many complex diseases that integrate innate and adaptive immune mechanisms and requires careful study to maximize host protective effects and minimize host deleterious effects.

Figure 1. IL-6 signalling and trans-signalling. IL-6 interacts with its ligand-binding receptor, the IL-6Ralpha, either membranebound (classical signaling) or in a soluble form (trans-signaling), and the complex associates with gp130 triggering its dimerization and consequent activation of the associated JAK kinases. These mediate the phosphorylation of specific tyrosine residues (P) on the gp130 cytoplasmic tail, which in turn act as docking sites for STAT3 (and STAT1) SH2 domains, leading to JAK-mediated STAT3 phosphorylation, dimerization and concentration in the nucleus, where it regulates transcription of target genes. SOCS3 negatively regulates IL-6 signaling by interacting with gp130 phosphotyrosine-759 and leading to the inhibition of JAK activity through its kinase inhibitory region. Soluble forms of both IL-6Ralpha and gp130 (sIL-6Ralpha, sgp130), which lack the transmembrane and cytoplasmic parts, are highly produced under pathological conditions, acting as IL-6 trans-signaling agonist (sIL-6Ralpha) or antagonist (sgp130), respectively.  
Figure 2. The positive feedback loop between IL-6, IL-17 and STAT3. IL-6 in combination with TGFbeta promotes STAT3- dependent Th17 differentiation of naïve CD4 + T cells, while TGFbeta in the absence of IL-6 triggers the differentiation of TGFbeta T regulatory cells (Tregs). The proinflammatory cytokine IL-23 triggers Th17 expansion, but full responsiveness to IL- 23 requires STAT3-dependent IL-23R up-regulation by IL-6. IL-17, the main cytokine produced by Th17 cells, provides defence against extracellular bacteria and mediates inflammation, tissue damage and recruitment of immune cells. IL-17 acts on stromal cells to sustain NF-kB-mediated IL-6 expression, which in turn enhances Th17 differentiation in a positive feedback loop. In addition, stimulated stromal cells attract neutrophils, which generate sIL-6R by shedding thus leading to trans-signaling in  
IL-6, IL-17 and STAT3: a holy trinity in auto-immunity?
Interleukin-6 (IL-6) is a pleiotropic cytokine involved in the regulation of the cross talk between haematopoietic/immune cells and stromal cells, including the onset and resolution of inflammation, responses to infection, tissue remodelling and cancer. It is produced, among others, by fibroblasts, endothelial cells, macrophages and lymphocytes. IL-6 can interact with both membrane-bound and soluble forms of its ligand-binding receptor, the IL-6Ralpha, triggering signalling via dimerization of gp130, the signalling subunit of the IL-6 receptor complex. This leads to the activation of the JAK/STAT pathway and mainly culminates in the activation of the STAT3 transcription factor. Both IL-6 and STAT3 have recently emerged as main regulators of the differentiation and function of Th17 cells, via a positive feedback loop enhancing expression and/or activation of IL-6 itself, IL-17 and STAT3. Dysregulated IL-6 production and signalling are associated with chronic inflammatory diseases, auto-immunity and cancer, and are the object of intense translational research as promising therapeutic targets.

Figure 1. Th17 Cell Differentiation. Upon activation by antigen presenting cells, naïve T helper cells can differentiate into different T helper subsets. In the presence of TGF-β and proinflammatory cytokines such as IL-6, IL-23, or IL-1β, naïve T cell differentiates into Th17 cells. The differentiation of Th17 is inhibited by hallmark cytokines of other T helper subsets. Pro-inflammatory cytokines can induce further effector molecules in committed Th17 cells to establish their terminally differentiated effector phenotype.
Figure 2. 
Figure 3. 
Figure 4. 
Th 17 cells interplay with Foxp3+ Tregs in regulation of inflammation and autoimmunity
T helper 17 cells (Th17) are a new CD4+ T helper subset that has been implicated in inflammatory and autoimmune diseases. Th17, along with CD4(+)CD25(high) Foxp3(+) regulatory T cells (Tregs) and other new T helper subsets, have expanded the Th1-Th2 paradigm. Although this new eight-subset paradigm significantly improved our understanding on the differentiation and regulation of CD4+ T helper subsets, many questions remain to be answered. Here we will briefly review the following issues: a) Old Th1-Th2 paradigm versus new multi-subset paradigm; b) Structural features of IL-17 family cytokines; c) Th17 cells; d) Effects of IL-17 on various cell types and tissues; e) IL-17 receptor and signaling pathways; f) Th17-mediated inflammations; and g) Protective mechanisms of IL-17 in infections. Lastly, we will examine the interactions of Th17 and Treg in autoimmune diseases and inflammation: Th17 cells interplay with Tregs. Regulation of autoimmunity and inflammation lies in the interplays of the different T helper subsets, therefore, better understanding of these subsets' interactions would greatly improve our approaches in developing therapy to combat inflammatory and autoimmune diseases.

The clinical significance of sperm-zona pellucida binding: 17 Years later

February 2006

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64 Reads

The development of homologous functional bio-assays for sperm quality assessment has been a focal point of reproductive biologists in order to provide a scientifically- based diagnosis in cases of fertilization failure. The availability of viable oocytes still remains an important limiting factor for laboratories to embark on the methodology of assays that examine sperm-oocyte interaction. The use of zonae pellucidae obtained from oocytes derived from post mortem tissue and failed in vitro fertilization cycles, enhanced the availability of zona material. Sperm-zona pellucida binding has been illustrated to be an essential requisite during human fertilization. This fundamental biological step can be measured under hemizona assay as well intact-oocyte test conditions. The sensitivity and specificity of sperm-zona binding results indicated the assay to be positively and significantly correlated with in vitro fertilization outcome. Furthermore, highly significant correlations were demonstrated between normal sperm morphology, hyperactivated motility, sperm creatine kinase activity and the zona binding capacity of a given sperm sample. It was concluded that andrology testing remains an ever-growing component in the work-up of the infertile couple. We enter the next millennium with many questions that remain to be answered by the hand of efficacious screening techniques and a new formidable therapy in intracytoplasmic sperm injection.

Dual specificity phosphotase 18, interacting with SAPK, dephosphorylates SAPK and inhibits SAPK/JNK signal pathway in vivo

February 2006

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63 Reads

The SAPK/JNKs play important roles in numerous cellular processes, and for this reason they have become putative drug targets. Most dual-specificity protein phosphatases (DSPs) play important roles in the regulation of mitogenic signal transduction and cell cycle control in response to extracellular stimuli. Dual-specificity phosphatase 18 (DUSP18), a newly recognized SAPK/JNK phosphatase, is widely expressed. This expression is modulated in response to extracellular stimuli. By phosphorylation assay, pull down and coimmunoprecipitation experiments, it is shown here that DUSP18 interacts with SAPK/JNK and dephosphorylates it both in vitro and in vivo. DUSP18 does not dephosphorylate p38 or p44ERK1. Furthermore, DUSP18 inhibits SAPK/JNK pathway in vivo. Based on these findings, DUSP18 appears to serve an important role by regulation of SAPK/JNK pathway.

Imaging of early inflammation in low-to-moderate carotid stenosis by 18-FDG-PET

February 2009

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53 Reads

It is not clear if 18FDG-PET can be useful for detection of inflammation in low to moderate carotid stenosis. We studied 15 patients scheduled for endarterectomy with contralateral carotids with less than 50% stenosis. 18-FDG-PET was performed prior to CEA and 3 months following surgery. FDG-uptake values were calculated based on maximum standardized uptake value (SUV) and corresponding uptake ratios. We confirmed by CD68 macrophage staining that FDG accumulation corresponds to active inflammation (R=0.8 p less than 0.005). We found significant correlation between the FDG-uptake in the carotids scheduled for CEA and contralateral carotids with low to moderate stenosis (R=0.9 p less than 0.001). The FDG uptake ratio in the contralateral arteries remained stable on the follow-up imaging (1.15+/-0.2 vs. 1.14+/-0.1, R=0.7 p=0.006). We did not find correlation between FDG uptake and symptomatic or asymptomatic patients, degree of carotid stenosis and vascular risk factors. This is a prospective, preliminary in vivo study demonstrating that low to moderate carotid atherosclerosis can be detected using 18-FDG-PET imaging and highlights the truly systemic nature of atherosclerosis.

Figure 1. Activity based probes for TGase 2. (A) Schematic representation for the synthesis of biotinylated spermidine. Step i , protection of amine groups; reaction of di- tert -butyl dicarbonate and 1, 4-dioxane for 22 h at RT. Step ii , biotinylation; reaction mixture comprises biotin, 1-(3-dimethylaminopropyl-3-ethyl carbodiimid) chlorohydrate, 1-hydroxybenzotriazol and dimethylformamide for 24 h at room temperature. Step iii , deprotection of amine groups; 1M ethereal HCl and methanol for 1 h at 0 ° C. Each reaction was monitored by thin layer chromatography using pre-coated silica gel plate (60 mesh) with fluorescence indicator, and reaction products were purified by column chromatography using silica gel columns (230-400 mesh). (B) Schematic representations of biotinylated spermidine (BSPD, left) and biotinylated spermine (BSPM, right). 
Figure 2. Evaluation of biotinylated polyamines as substrates for polyamination of proteins by TGase 2. (A) Incorporation of BP, BSPD or BSPM into N,N’ -dimethylcasein catalyzed by TGase 2. A solid-phase microtiter plate transamidation assay was developed to measure the extent of polyamination at various polyamine concentrations. The extent of polyamination was probed by HRP-conjugated streptavidin. O -phenylenediamine dihydrochloride solution was added and the absorbance at 490 nm was measured. The figure presents typical data in three independent experiments. (C) Cytochemical staining of BSPD or BSPM incorporated into cellular proteins. Human diploid fibroblast was incubated with either BSPD or BSPM and probed using Texas Red-conjugated streptavidin. Cystamine was used to inhibit TGase 2 activity in the system. 
Figure 3. Analysis of HPV 18 E7 polyamination. (A) Visualization of polyaminated HPV 18 E7. E7 was expressed in BL21 cells as a polyhistidine-tagged form and purified with nickel affinity resin. The polyamination of E7 with either BSPD or BSPM (0.1 mM each) was catalyzed by TGase 2. For competition experiments, the above reaction was performed in the presence or in the absence of SPD or SPM at various concentrations, respectively. The reaction mixture was analyzed by 15% SDS-PAGE and the incorporated BSPD or BSPM was probed with HRP-conjugated streptavidin as indicated in Materials and Methods. (B) E7 was subjected to TGase reaction with BP in the presence or in the absence of SPD or SPM. The reaction mixture was analyzed by a microtiter plate assay and the incorporated BP was probed with HRP-conjugated streptavidin as indicated Materials and Methods. 
Figure 4. Binding of Rb to polyaminated HPV 18. (A) HPV 18 E7 was incubated with spermidine or spermine in the presence or in the absence of TGase 2. The wells of a microtiter plate were coated with unmodified E7 protein or E7 polyaminated with spermidine or spermine (3 microgram/ml) and incubated with GST-Rb at various concentrations. Bound GST-Rb was detected using anti-GST monoclonal antibodies coupled with HRP-conjugated goat anti-mouse IgG antibodies. The chromogenic substrate O -phenylenediamine dihydrochloride developed a color the intensity of which was evaluated by measuring the absorbance at 490 nm. The figure presents typical data in three independent experiments. (B) HPV 18 E7 or its mutant Q87,88R protein was incubated with spermidine or spermine in the presence (SPM or SPD) or in the absence (NT) of TGase 2. Bound GST-Rb was evaluated using a solid-phase ELISA as described in Methods and Materials. Q87,88R represents a mutant of HPV18 E7 which lacks the sites for polyamination. Rb binding to the polyaminated E7 proteins is expressed as a relative value to that of the wild- type. The figure shows the mean values and standard deviation based on three independent experiments. 
Figure 5. Alteration of HPV 18 E7 activity by treatment with SPD or SPM in HepG2 cells. A plasmid containing six consecutive E2F responsive elements (6 × E2F) upstream of a luciferase gene was used as a reporter construct. HepG2 cells were transiently transfected with the reporter construct and pcDNA3-HPV18 E7 plus pCMV-beta-Gal. (A) After 20 h of transfection, the cells were treated with 0.5 mM SPD or SPM for 4 h. NT denotes no treatment with either SPD or SPM. Mock indicates empty pcDNA3 vector. Luciferase activity is normalized by beta-galactosidase activity, and expressed relative to the activity of the reporter construct alone. (B) HPV18 E7-transfected cells were treated 0.5 mM SPD or SPM in the presence or in the absence of 0.5 mM cystamine (CT) for 4 h. Polyamination-defective mutant Q87,88R E7 was used to assess the effect of 0.5 mM SPD or SPM on reporter activity. The figure shows the mean values and standard deviation based on four to six independent experiments. 
Alteration of Rb binding to HPV 18 E7 modified by transglutaminase 2 with different type of polyamines

February 2006

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170 Reads

High-risk human papillomavirus (HPV) E7 is a major oncoprotein that plays a crucial role in the development of cervical cancer. A previous study showed that transglutaminase (TGase) 2 catalyzes the incorporation of polyamines into HPV 18 E7 protein, and thereby diminishes its ability to bind Rb. Therefore, TGase 2 activity may be implicated in a suppressive function of host against HPV-induced carcinogenesis. To better understand the nature of polyamination of HPV 18 E7, we investigated the Rb binding of E7 polyaminated in vitro with different type of polyamines. The incorporation of spermine diminished the Rb binding of E7 more profoundly compared with that of spermidine, suggesting that either the additional positive charge or a steric effect or both may have altered the chemical or structural properties of the protein. In addition, the treatment of either spermidine or spermine in cultured cell system reduced the ability of E7 to inactivate Rb with a TGase activity-dependent manner. Spermine was more effective in inhibiting E7 activity than spermidine. These results may provide the basis for future investigation aiming at delineating the significance of polyamine metabolism on HPV E7 functions.

Figure 1. The metabolic fate of FDOPA. The vertical dashed line signifies the blood-brain barrier. Anatomical subcompartments in the brain are ignored with the exception of the FDA protected from metabolism by storage in vesicles, signified by the surrounding ellipse. Enzyme catalyzed reactions are labeled with the associated enzyme name in italics. The full names of all compounds and enzymes are provided in the text. All processes described in the introductory paragraphs are shown, with the addition of the COMT-catalyzed metabolism of FDOPA to 3-O-methyl-fluorodopa (3OMFD) in both periphery and brain. 
Table 1 . Summary of monkeys used for tissue assay 
Table 3 . Comparison of the striatal FDOPA metabolite fractions predicted by Models I and II and measured in tissue 
Figure 4. The fractions of FDOPA and its radioactive metabolites measured at 30 and 90 minutes post-injection. The values in striatum were obtained by averaging the radioactive metabolite fractions in caudate and putamen shown in Table 2. Those in cortex were obtained by averaging the radioactive metabolite fractions in frontal cortex, occipital cortex, and cerebellum shown in Table 2. 
Endres CJ, DeJesus OT, Uno H, Doudet DJ, Nickles JR, Holden JETime profile of cerebral [18F]6-fluoro-L-DOPA metabolites in nonhuman primate-implications for the kinetics of therapeutic L-DOPA. Front Biosci 9:505-512

February 2004

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256 Reads

At least two rates of dopamine turnover have been demonstrated in vivo, including a slow turnover rate that is associated with synaptic vesicles, and a faster rate that leads to rapid production of dopamine metabolites. Similarly, [18F]6-fluorodopamine (FDA), the decarboxylation product of the PET tracer [18F]6-fluoro-L-DOPA (FDOPA), may have multiple turnover rates which could substantially affect the interpretation of FDOPA uptake. To better characterize FDA turnover in vivo, we measured the formation of FDOPA metabolites in primate brain following bolus FDOPA injection with carbidopa pretreatment. FDOPA was allowed to circulate for either 30 minutes or 90 minutes, prior to removal of brain samples. The primary metabolites in striatum were [18F]6-fluoro-3-methyl-L-DOPA (3-OMFD), FDA, [18F]6-fluoro- L-3,4-dihydroxyphenylacetic acid (FDOPAC), and [18F]6-fluorohomovanillic acid (FHVA). The percentages of total radioactivity in striatum at 30 minutes and 90 minutes were: FDOPA(5%, 2%), FDA (39%, 23%), FDOPAC (12%, 3%), FHVA (14%, 34%), and 3-OMFD (29%, 39%). In cortex and cerebellum most of the activity (73%, 80%) was 3-OMFD. These data were compared against the metabolite profiles predicted by two compartmental models of FDOPA metabolism. A model that assumes only a single slow rate of FDA turnover predicted much lower concentrations of FDA metabolites (FDOPAC, FHVA) in striatum than were found in the brain assay, while a model that includes both slow and fast FDA turnover was in much better agreement. These findings extend and confirm previous observations of FDOPA metabolites. The implications for the interpretation of FDOPA PET, particularly in terms of the availability of dopamine synthesized from therapeutic L-DOPA, are discussed.

Discovery of alternative DNA structures: A heroic decade (1979–1989)

February 2008

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364 Reads

The first alternative DNA structure--left-handed Z-DNA--was described back in 1979. The discoveries of the cruciform DNA structure, three-stranded H-DNA, four-stranded G-quartets and stably unwound DNA followed in the next decade. Each alternative structure was formed by a specific DNA sequence, which as a rule was repetitive. Furthermore, these repetitive elements were situated at functionally important areas of various genomes, pointing to the biological significance of these structures. This chapter concentrates on the first period of studies of alternative DNA structures, beginning in 1979 and ending in 1989, which transformed our views on DNA structure and functioning.

Xenotransplantation–state of the art–update 1999

May 1999

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35 Reads

Organ transplantation is limited by the number of cadaveric human donor organs that become available. Xenotransplantation - the transplantation of organs and tissues between animal species - would supply an unlimited number of organs and offer many other advantages. The pig has been identified as the most suitable donor animal. Pig organs, when transplanted into humans or nonhuman primates, are, however, rejected hyperacutely within minutes by antibody-mediated complement activation. Human anti-pig antibodies have been identified as being directed against galactose alpha 1-3galactose (alpha Gal) epitopes on pig vascular endothelium. Methods have been successfully developed to prevent hyperacute rejection. These include (i) depletion or inhibition of recipient antibodies or complement and (ii) development of transgenic pigs that express a human complement-regulatory protein (e.g. hDAF). The persistence or return of anti-pig antibody, however, even following the use of hDAF pig organs, eventually leads to what has been variously termed "acute vascular rejection" or "delayed xenograft rejection", which is again believed to be largely antibody-dependent. Nevertheless, experimental pig-to-primate organ xenotransplantation now results in transplant function for days and weeks rather than minutes. Little is yet known of the nature of the acute cellular rejection response that is anticipated to follow, and of any subsequent chronic rejection that may develop. Tolerance to both the alpha Gal epitope and to swine leukocyte antigens (SLA) is being explored using gene therapy techniques and by the induction of hematopoietic cell chimerism. The development of genetically engineered pigs that do not express the alpha Gal epitope is also being pursued. Considerable progress has been made in recent years, but experimental results do not yet warrant the initiation of a clinical trial of organ xenotransplantation. However, trials are already underway of pig cell transplants in patients with diabetes and neurodegenerative conditions, such as Parkinson's disease.

Table 1 . FISH Patterns vs. Glioma Type 
Figure 1.Representative FISH hybridizations. A) Central neurocytoma with a normal disomic complement of 1p (green) and 19q (red) signals. Most cells have 2 green and/or 2 red signals, though some have less due to the truncation artifact encountered in thin tissue sections (i.e. incomplete DNA complement in sectioned nuclei). Also, some signals are beyond the planes of focus represented in the photograph. B) Pattern of 1p/19q codeletion in an oligodendroglioma with 1 green and 1 red signal detected in most nuclei. C) Recurrent anaplastic oligodendroglioma with a relative 1p deletion as evidenced by the presence of up to 4 chromosome 1q (red) and 2 1p (green) signals in tumor nuclei. D) Small cell GBM containing overlapping morphologic features with anaplastic oligodendroglioma. It displayed EGFR gene amplification with innumerable EGFR signals (red), rather than 1p/19q deletions. A chromosome 7 centromere-enumerating probe (CEP7, green) was utilized as the reference probe for delineating copy numbers of chromosome 7. 
Table 3 . FISH Patterns vs. Tumor Location 
Ancillary FISH analysis for 1p and 19q status: preliminary observations in 287 gliomas and oligodendroglioma mimics

February 2003

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1,367 Reads

Deletions of chromosomes 1p and 19q are associated with chemosensitivity and enhanced survival in oligodendrogliomas. Therefore, we have utilized FISH analysis as an ancillary tool for diffuse gliomas with suspected oligodendroglial features. To date, 246 gliomas have been analyzed in 131 male and 93 female patients, including 109 oligodendrogliomas (O), 109 mixed oligoastrocytomas/equivocal gliomas (MOA), and 28 astrocytomas (A). To address specificity, we also analyzed 41 oligodendroglioma mimics, including 12 central and 12 extraventricular neurocytomas (EVN), 12 dysembryoplastic neuroepithelial tumors, and 5 clear cell ependymomas. Aside from 2 EVNs, no mimics demonstrated codeletion. Three patterns were associated with glioma cell type (O vs. MOA/A): -1p/19q, -19q alone, and polysomies. Long-term survivals of >5-years (N=47) and >10-years (N=16) were associated with 1p/19q codeletion in 60% and 75% respectively, whereas solitary 19q deletion accounted for 11% and 6% respectively. Survivals<2-years (N=10) were associated with lack of deletions in 70%. A few older patients with high-grade, "genetically favorable" tumors did poorly, whereas prolonged survival was observed in several low-grade glioma patients despite a lack of the "genetically favorable" pattern. Our data suggests that: 1) FISH-detectable 1p/19q codeletion is relatively specific for oligodendrogliomas with long survival, 2) solitary 19q deletion may also portend a favorable prognosis in a smaller subset, and 3) combined clinicopathologic and genetic assessment likely provides a more accurate means of patient stratification than either one alone.

Figure 1. Quantification of glycosaminoglycans (μg/μg DNA) in the supernatant of HCS2/8 cells after stimulation with BMP-7. Cells were cultured in control medium or stimulated with BMP-7 (600 ng/ml) for 3 days and GAGs were quantitated in the supernatant and DNA in the cell pellet, respectively. The amount of GAGs ( ± standard deviation) is given relative to the amount of DNA. A non-parametric Mann-Whitney test (software GraphPadPrism 4.0) was used for statistical analysis. 
Table 1 . Sequences of primers and probes for real-time PCR experiments
Figure 2. Clustering of regulated genes and stimulation experiments in HCS-2/8 cells treated with BMP-7. For the five time intervals of BMP-7 stimulation, expression profiles of treated samples were compared to control samples (triplicates each) and genes with a 1,5 fold change (and a corresponding p-values of less than 0,001) were considered regulated and were used for clustering. Hierarchical clustering groups the two most similar objects into a cluster (similarity was determined using Euclidean distance) and than keeps joining the most similar object to the newly formed cluster. The figure shows a dendrogram for gene profiles (columns) and for experiments (rows) respectively, as the result of a two dimensional clustering. The scale with correlation values for clusters is plotted for both dimensions. The direction and magnitude of gene regulation is indicated by colour type/saturation (green: down-regulated genes, red: up-regulated genes).
Figure 3. Temporal regulation of genes in HCS-2/8 cells after stimulation with BMP-7. (a) Graphical representation of genes showing a regulation at two (or more) time points within the timecourse (30 min, 6 , 16 , 24 and 48 hours) of at least 1,5 fold and a corresponding p-value less than 0,001. Genes of the BMP/TGF-family and BMP/TGF-signalling molecules are marked in red.
Figure 4. Validation of changes of gene expression levels in the cDNA-array experiments using quantitative PCR: shown are ratios (stimulated versus un-stimulated) for Col2, aggrecan, BMP-2, TIMP-3 and Smad 6 for the different time points (6 hrs, 16 hrs, 24 hrs, 48 hrs). 
The human chondrosarcoma HCS-2/8 cell line is responsive to BMP-7, but not to IL-1beta

February 2005

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251 Reads

Cultures of primary chondrocytes as in vitro model systems for studying the cellular behavior of chondrocytes are notoriously difficult to cultivate and propagate. One way to circumvent these problems appears to be the use of immortalized/immortal chondrocytic cell lines. In the present study, we were interested whether the chondrosarcoma derived HCS-2/8 cells are suitable for studying major cellular reaction pattern in response to key anabolic (BMP-7) and catabolic (IL-1beta) factors. Therefore, we used cDNA array and real-time PCR technology in order to evaluate gene expression triggered by stimulation with IL-1beta (0,1-100 ng/ml) and BMP-7 in confluent monolayer cultures. HCS-2/8 cells hardly responded to IL-1beta, but showed good responsiveness to BMP-7. We found 12 genes up- and 17 significantly down-regulated by BMP-7 (out of 340 investigated genes). Besides the expected activation of anabolic genes chondrocytic cells after BMP-stimulation try to neutralize activation of the BMP-signalling cascade by expressing intra- and extracellular BMP-antagonists. Chondrosarcoma derived cell lines are a potential substitute for primary articular chondrocytes promising consistent expression of a differentiated chondrocyte phenotype with sufficient proliferative capacity. However, as shown by this study one needs to carefully select the cell line depending on the effects which one intends to study. In this respect, HCS-2/8 cells are a validated tool for studying BMP-effects on chondrocytes, but not e.g. effects of interleukin-1.

Tollip attenuated the hypertrophic response of cardiomyocytes induced by IL‐1beta

February 2009

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45 Reads

We examined the role of Tollip in the hypertrophic response of cardiomyocytes. C57BL/6 mice were subjected to transverse aortic constriction (TAC) for 2 weeks and age-matched sham surgical operated mice served as control. TAC significantly reduced the association of Tollip with IRAK-1 by 66.4 percent and increased NF-kappaB binding activity by 86.5 percent and the levels of phospho-p38 by 114.6 percent in the myocardium compared with sham control, respectively. In vitro experiments showed that IL-1beta stimulation also significantly reduced the association of Tollip with IRAK-1 and increased NF-kappaB binding activity in neonatal cardiomyocytes. Tollip overexpression by transfection of cardiac myocytes significantly attenuated the IL-1beta-induced hypertrophic response of cardiac myocytes as evidenced by reduced cell size (16.4 percent) and decreased ANP expression (33.3 percent). Overexpression of Tollip also reduced NF-kappaB binding activity by 30.7 percent and phospho-p38 by 47.1 percent, respectively. The results suggest that Tollip could be a negative regulator during the development of cardiac hypertrophy. The negative regulation of cardiac hypertrophy by Tollip may involve downregulation of the MyD88-dependent NF-kappaB activation pathway.

Profiling of hepatocellular proteins by 1D PAGE-MALDI/MS/MS in a rat heat stress model

February 2006

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14 Reads

Heat induced complications cause an increase in a large number of proteins which play a role in diverse pathways during heat shock. A detailed characterization of these proteins is essential for understanding the molecular mechanisms involved in heat stroke. In this report, the proteins present in rat liver were compared at 37 degrees C (control) and at core temperature (Tc) 42 degrees C (heat stress) by 1D PAGE and MALDI/MS/MS. Among proteins identified in the sample after heat stress are dimethyglycine dehydrogenase, transketolase, carboxylic ester hydrolase, pyruvate kinase, L-type pyruvate kinase, arginosuccinate synthetase; fumarylacetoacetate hydrolase and peptidylpropyl isomerase A. These findings show that analysis of large scale proteins by MALDI/MS/MS provides a better understanding of the molecular mechanisms associated with heat shock. The resolution of proteins examined by 1D-PAGE was less than that obtained with 2D-PAGE. More specifically, 2D-PAGE allows better identification of low molecular weight proteins that can not be resolved by 1D-PAGE.

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