Publications (31)134.64 Total impact
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Article: Propofol prevents cerebral ischemia-triggered autophagy activation and cell death in the rat hippocampus through the NF-κB/p53 signaling pathway.
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ABSTRACT: Propofol (2,6-diisopropylphenol) has been shown to attenuate neuronal injury under a number of experimental conditions; however, the mechanisms involved in its neuroprotective effects remain unclear. We therefore investigated whether inhibition of p53 induction by propofol contributes to the neuroprotection of cerebral ischemic cell death through both autophagic and apoptotic mechanisms. A transient global cerebral ischemia-reperfusion (I/R) model was produced with a 10-minute, 2-vessel occlusion. The change in target genes including damage-regulated autophagy modulator (DRAM), microtubule-associated protein 1 light chain 3 (LC3), Beclin 1, cathepsin D, cathepsin B, p53-upregulated modulator of apoptosis (PUMA), Bax and Bcl-2 upon p53 inhibition was assessed with the co-administration of the intravenous anesthetic propofol and 3-methyladenine (3-MA), Pifithrin-alpha (PFT-α) or SN50. The I/R-induced increases of protein levels of p53 and LC3-II were significantly inhibited by treatment with propofol, 3-MA or PFT-α. The I/R-induced increases of protein levels of DRAM, Beclin 1, active cathepsin D and cathepsin B were significantly inhibited by treatment with propofol, PFT-α or SN50. The negative effects of the I/R-induced up-regulation of PUMA and Bax and the down-regulation of Bcl-2 in the rat hippocampus were all blocked by treatment with propofol, PFT-α or SN50. Our results suggest that cerebral ischemia-reperfusion can induce NF-κB-dependent expression of p53. The autophagic and apoptotic mechanisms participate in programmed cell death by regulating the p53-mediated pathway. Our results are the first to show that propofol, at clinically relevant concentrations, attenuated cell death through both autophagic and apoptotic mechanisms in the rat hippocampus after a cerebral I/R insult.Neuroscience 05/2013; · 3.38 Impact Factor -
Article: Distribution and Genetic Characterizations of Cryptosporidium spp. in Pre-Weaned Dairy Calves in Northeastern China's Heilongjiang Province.
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ABSTRACT: BACKGROUND: Cryptosporidium spp. are common parasites of humans and animals. Farm animals, especially pre-weaned calves, are considered to be one of main animal reservoir hosts of Cryptosporidium in the transmission of human cryptosporidiosis. The aim of this study was to determine the distribution and genotypes of Cryptosporidium spp. in pre-weaned calves using molecular tools and to assess zoonotic transmission and elucidate the public health significance in northeastern China. METHODOLOGY/PRINCIPAL FINDINGS: A total of 151 fecal specimens from pre-weaned calves were collected in Heilongjiang Province and were screened for Cryptosporidium by PCR. The average prevalence of Cryptosporidium was 47.68% (72/151). Cryptosporidium spp. were characterized by DNA sequencing of the small subunit (SSU) rRNA gene and the 60-kDa glycoprotein (gp60) gene. Based on the SSU rRNA gene, five Cryptosporidium spp. were identified, including C. bovis (n = 34), C. andersoni (n = 26), C. ryanae (n = 5), C. meleagridis (n = 5) and C. parvum (n = 2). The SSU rRNA nucleotide sequences were identical to each other, respectively, within C. ryanae, C. parvum, C. meleagridis and C. andersoni. Four types of C. bovis were found in the SSU rRNA gene, with two novel types. The gp60 gene was successfully sequenced in one C. parvum isolate and three C. meleagridis isolates, with IIdA19G1 for C. parvum and IIIeA22G2R1 for C. meleagridis. CONCLUSION/SIGNIFICANCE: Molecular analysis indicates that Cryptosporidium spp. are endemic in pre-weaned calves in Heilongjiang Province. The findings of C. parvum and C. meleagridis suggested the possibility of zoonotic transmission and public health significance. The transmission dynamics of C. parvum and C. meleagridis needed to be clarified by further molecular epidemiologic studies from humans and animals. Whether calves could act as the natural reservoirs of C. meleagridis needed to be confirmed by more systematic experimental infection studies.PLoS ONE 01/2013; 8(1):e54857. · 4.09 Impact Factor -
Article: TPC Proteins Are Phosphoinositide- Activated Sodium-Selective Ion Channels in Endosomes and Lysosomes.
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ABSTRACT: Mammalian two-pore channel proteins (TPC1, TPC2; TPCN1, TPCN2) encode ion channels in intracellular endosomes and lysosomes and were proposed to mediate endolysosomal calcium release triggered by the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). By directly recording TPCs in endolysosomes from wild-type and TPC double-knockout mice, here we show that, in contrast to previous conclusions, TPCs are in fact sodium-selective channels activated by PI(3,5)P(2) and are not activated by NAADP. Moreover, the primary endolysosomal ion is Na(+), not K(+), as had been previously assumed. These findings suggest that the organellar membrane potential may undergo large regulatory changes and may explain the specificity of PI(3,5)P(2) in regulating the fusogenic potential of intracellular organelles.Cell 10/2012; 151(2):372-83. · 32.40 Impact Factor -
Article: Electronic structure and magnetism of La(4)Ni(3)O(8) from first principles.
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ABSTRACT: The magnetic and electronic properties of La(4)Ni(3)O(8) are investigated by performing the full-potential linearized augmented plane wave method. The C-type antiferromagnetic spin ordering is preferred and a molecular correlated insulating state with high-spin Ni ions is found. Our results have proved that this insulating state is caused by a correlation effect and the strong interlayer interaction. Such strong interlayer coupling results from the high-spin occupation of Ni ions.Journal of Physics Condensed Matter 09/2012; 24(40):405502. · 2.55 Impact Factor -
Article: Signal amplification based on DNA hybridization-dehybridization reaction on the surface of magnet submicrobeads for ultrasensitive DNA detection.
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ABSTRACT: A new signal amplification strategy based on DNA hybridization-dehybridization reaction on the surface of magnetic submicrobeads (MSBs) for fluorescence detection of ultrasensitive DNA was developed. In this strategy, MSBs modified with probe DNA (DNAp-MSBs) were bound to target DNA (t-DNA) (with a ratio of 1 : 1) captured to a substrate. The DNAp-MSBs were released from the substrate via DNA dehybridization and then hybridized with Cy5-labeled detection DNA (Cy5-DNAd). After the Cy5-DNAd and DNAp-MSBs were separated by dehybridization, the Cy5-DNAd was collected. The DNAp-MSBs were then hybridized with other Cy5-DNAd to initiate the next hybridization-dehybridization round. This recycling of the hybridization-dehybridization process on the surface of the DNAp-MSBs was repeated multiple times to accumulate Cy5-DNAd. Finally, fluorescence intensity of the collected Cy5-DNAd was measured. Using this strategy, the limit of detection for determination of t-DNA was 8.5 × 10(-15) mol L(-1) for 11 cycles. The ultrasensitive assay was used to quantify ribosomal protein, large, P2 (RPLP2) mRNA in human breast cancer cells.The Analyst 09/2012; 137(20):4849-54. · 4.23 Impact Factor -
Article: Genetic Characterizations of Giardia duodenalis in Sheep and Goats in Heilongjiang Province, China and Possibility of Zoonotic Transmission.
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ABSTRACT: Giardia duodenalis is a widespread intestinal protozoan of both humans and mammals. To date, few epidemiological studies have assessed the potential and importance of zoonotic transmission; and the human giardiasis burden attributable to G. duodenalis of animal origin is unclear. No information about occurrence and genotyping data of sheep and goat giardiasis is available in China. The aim of the present study was to determine prevalence and distribution of G. duodenalis in sheep and goats in Heilongjiang Province, China, and to characterize G. duodenalis isolates and assess the possibility of zoonotic transmission. A total of 678 fecal specimens were collected from sheep and goats on six farms ranging in age from one month to four years in Heilongjiang Province, China. The average prevalence of G. duodenalis infection was 5.0% (34/678) by microscopy after Lugol's iodine staining, with 5.6% (30/539) for the sheep versus 2.9% (4/139) for the goats. Molecular analysis was conducted on 34 G. duodenalis isolates based on the triosephosphate isomerase (tpi) gene. 29 tpi gene sequences were successfully obtained and identified as assemblages A (n = 4), B (n = 2) and E (n = 23). High heterogeneity was observed within assemblage E at the tpi locus, with five novel subtypes found out of seven subtypes. Two subtypes of assemblage A were detected, including subtype AI (n = 3) and a novel subtype (designated as subtype AIV) (n = 1). Two assemblage B isolates were identical to each other in the tpi gene sequences. This is the first report of G. duodenalis infections in sheep and goats in China. The present data revealed the unique endemicity on prevalence, distribution and genetic characterization of G. duodenalis in sheep and goats in Heilongjiang Province. The findings of assemblages A and B in sheep and goats implied the potential of zoonotic transmission.PLoS Neglected Tropical Diseases 09/2012; 6(9):e1826. · 4.69 Impact Factor -
Article: Phosphoinositide isoforms determine compartment-specific ion channel activity.
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ABSTRACT: Phosphoinositides serve as address labels for recruiting peripheral cytoplasmic proteins to specific subcellular compartments, and as endogenous factors for modulating the activity of integral membrane proteins. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) is a plasma-membrane (PM)-specific phosphoinositide and a positive cofactor required for the activity of most PM channels and transporters. This requirement for phosphoinositide cofactors has been proposed to prevent PM channel/transporter activity during passage through the biosynthetic/secretory and endocytic pathways. To determine whether intracellularly localized channels are similarly "inactivated" at the PM, we studied PIP(2) modulation of intracellular TRPML1 channels. TRPML1 channels are primarily localized in lysosomes, but can also be detected temporarily in the PM upon lysosomal exocytosis. By directly patch-clamping isolated lysosomes, we previously found that lysosomal, but not PM-localized, TRPML1 is active with PI(3,5)P(2), a lysosome-specific PIP(2), as the underlying positive cofactor. Here we found that "silent" PM-localized TRPML1 could be activated by depleting PI(4,5)P(2) levels and/or by adding PI(3,5)P(2) to inside-out membrane patches. Unlike PM channels, surface-expressed TRPML1 underwent a unique and characteristic run-up upon patch excision, and was potently inhibited by a low micromolar concentration of PI(4,5)P(2). Conversely, depletion of PI(4,5)P(2) by either depolarization-induced activation or chemically induced translocation of 5'-phosphatase potentiated whole-cell TRPML1 currents. PI(3,5)P(2) activation and PI(4,5)P(2) inhibition of TRPML1 were mediated by distinct basic amino acid residues in a common PIP(2)-interacting domain. Thus, PI(4,5)P(2) may serve as a negative cofactor for intracellular channels such as TRPML1. Based on these results, we propose that phosphoinositide regulation sets compartment-specific activity codes for membrane channels and transporters.Proceedings of the National Academy of Sciences 06/2012; 109(28):11384-9. · 9.68 Impact Factor -
Article: Dopamine receptor D1 mediates the inhibition of dopamine on the distal colonic motility.
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ABSTRACT: The motility of distal colon could be inhibited by dopamine (DA), yet, the involved receptor is controversial according to the published reports. The goal of present study was to investigate DA receptor(s) mediated inhibition of DA on the colonic motility in rat. The contraction of isolated colon strips was assessed through isometric force transducer. The expressions of DA receptors in distal colon were detected through immunofluorescence and Western blot. DA concentration in colonic smooth muscle was measured by liquid chromatography/mass spectrometry. The results showed that DA inhibited the spontaneous motility of distal colon in a dose-dependent manner with EC50 8.3 μM. Tetrodotoxin increased colonic contractive frequency, but failed to affect the inhibition of DA on the colonic motility. Pretreatment with SCH-23390, an antagonist of dopaminergic receptor D1, shifted the dose-response curve to the right with EC50 of DA 37 μM. However, blocking dopaminergic receptor D2 with sulpiride, had no effect. The immunoreactivity of D1 and D2 were detected in the distal colon including myenteric plexus and smooth muscle. Acute cold-restraint stress (CRS) enhanced spontaneous contraction of rat distal colon, which was more sensitive to DA compared with control. Moreover, DA content and D1 expression in smooth muscle layer were increased under CRS condition. In conclusion, D1 in the smooth muscle is mediated DA inhibition on the spontaneous contraction of rat distal colon. The increased DA content and D1 receptor expression in the smooth muscle layer could be a compensatory effect under CRS condition to balance the enhanced colonic motility.Translational research : the journal of laboratory and clinical medicine. 05/2012; 159(5):407-14. -
Article: Antisense oligonucleotide knockdown of mGlu₅ receptor attenuates the antinociceptive tolerance and up-regulated expression of spinal protein kinase C associated with chronic morphine treatment.
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ABSTRACT: Spinal metabotropic glutamate receptor 5 (mGlu₅ receptor) is known to influence the development of intrathecal morphine antinociceptive tolerance. However, the signaling mechanisms remain unknown. We carried out intrathecal administration of an antisense oligodeoxynucleotide (ODN), which results in reduced expression of spinal mGlu₅ receptor, to determine its effects on morphine tolerance and spinal protein kinase C (PKC) expression. Rats were treated intrathecally with saline, morphine, mGlu5 receptor antisense ODN or mGlu5 receptor mismatched ODN. Behavioral tests were used to test the thermal and mechanical pain thresholds. Eight days later, rats were sacrificed and spinal cords were harvested to assess the expression of spinal PKC (α, γ and ε) by Western blotting and real-time polymerase chain reaction (PCR). Compared to control, intrathecal mGlu₅ receptor antisense ODN resulted in a ~53.9% reduction of spinal mGlu₅ receptor after 8days treatment. The mGlu5 receptor antisense ODN prevented the development of morphine tolerance. Expression of spinal PKC (α, γ and ε) was up-regulated at the mRNA and protein levels during the development of tolerance. Meanwhile, antisense ODN but not mismatched ODN reduced the spinal dorsal horn levels of PKC (α, γ and ε) which had been up-regulated after morphine exposure. We conclude that mGlu₅ receptor participates in the development of morphine tolerance. Expression of spinal PKC (α, γ and ε) at the mRNA and protein levels increased during morphine tolerance. Antisense ODN of mGlu₅ receptor prevented the tolerance and inhibited the altered expression of spinal PKC (α, γ and ε) during the development of tolerance.European journal of pharmacology 03/2012; 683(1-3):78-85. · 2.59 Impact Factor -
Article: Adrenomedullin expression in epithelial ovarian cancers and promotes HO8910 cell migration associated with upregulating integrin α5β1 and phosphorylating FAK and paxillin.
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ABSTRACT: Epithelial ovarian cancer (EOC) is one of the leading causes of cancer deaths in women worldwide. Adrenomedullin (AM) is a multifunctional peptide which presents in various kinds of tumors. In this study, we characterized the expression and function of AM in epithelial ovarian cancer using immunohistochemistry staining. Exogenous AM and small interfering RNA (siRNA) specific for AM receptor CRLR were treated to EOC cell line HO8910. Wound healing assay and flow cytometry were used to measure the migration ability and expression of integrin α5 of HO8910 cells after above treatments. Western blot was used to examine the phosphorylation of FAK and paxillin. We found that patients with high AM expression showed a higher incidence of metastasis, larger residual size of tumors after cytoreduction and shorter disease-free and overall survival time. Exogenous AM induced ovarian cancer cell migration in time- and dose- dependent manners. AM upregulated the expression of integrin α5 and phosphorylation of FAK, paxillin as well. Our results suggested that AM contributed to the progression of EOC and had additional roles in EOC cell migration by activating the integrin α5β1 signaling pathway. Therefore, we presumed that AM could be a potential molecular therapeutic target for ovarian carcinoma.Journal of Experimental & Clinical Cancer Research 03/2012; 31:19. · 2.15 Impact Factor -
Article: Occurrence of bovine giardiasis and endemic genetic characterization of Giardia duodenalis isolates in Heilongjiang Province, in the Northeast of China.
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ABSTRACT: To determine the prevalence of bovine giardiasis in Heilongjiang Province in China and to molecularly characterize Giardia duodenalis, feces were collected from 814 dairy and beef cattle ranging in age from 6 days to 9 years. Clinical symptoms of diarrhea were recorded at the time of sampling. The G. duodenalis infection rate in cattle was 5.2 % (42/814) as determined by Lugol's iodine staining. G. duodenalis assemblages and subtypes were genetically diagnosed by sequence analysis of the triosephosphate isomerase (TPI) gene. Three assemblages were identified, representing A (n = 1), B (n = 18), and E (n = 24), with a mixed infection case of assemblages A and E. High heterogeneity was also observed within assemblages B and E at the TPI locus. Among the assemblages, eight subtypes of assemblage B and three subtypes of assemblage E were found to be novel subtypes. Findings on assemblages A and B are of public health importance. The zoonotic potential of bovine giardiasis needs to be further assessed by extensive genetic data of assemblages A and B from humans at the subtype level. The newly found subtypes of assemblages B and E imply that the evaluation of geographically distributed subtypes is of importance.Parasitology Research 03/2012; 111(2):655-61. · 2.15 Impact Factor -
Article: Evidence for a stepwise program of extrathymic T cell development within the human tonsil.
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ABSTRACT: The development of a broad repertoire of T cells, which is essential for effective immune function, occurs in the thymus. Although some data suggest that T cell development can occur extrathymically, many researchers remain skeptical that extrathymic T cell development has an important role in generating the T cell repertoire in healthy individuals. However, it may be important in the setting of poor thymic function or congenital deficit and in the context of autoimmunity, cancer, or regenerative medicine. Here, we report evidence that a stepwise program of T cell development occurs within the human tonsil. We identified 5 tonsillar T cell developmental intermediates: (a) CD34⁺CD38dimLin⁻ cells, which resemble multipotent progenitors in the bone marrow and thymus; (b) more mature CD34⁺CD38brightLin⁻ cells; (c) CD34⁺CD1a⁺CD11c⁻ cells, which resemble committed T cell lineage precursors in the thymus; (d) CD34⁻CD1a⁺CD3⁻CD11c⁻ cells, which resemble CD4⁺CD8⁺ double-positive T cells in the thymus; and (e) CD34⁻CD1a⁺CD3⁺CD11c⁻ cells. The phenotype of each subset closely resembled that of its thymic counterpart. The last 4 populations expressed RAG1 and PTCRA, genes required for TCR rearrangement, and all 5 subsets were capable of ex vivo T cell differentiation. TdT⁺ cells found within the tonsillar fibrous scaffold expressed CD34 and/or CD1a, indicating that this distinct anatomic region contributes to pre-T cell development, as does the subcapsular region of the thymus. Thus, we provide evidence of a role for the human tonsil in a comprehensive program of extrathymic T cell development.The Journal of clinical investigation 03/2012; 122(4):1403-15. · 15.39 Impact Factor -
Article: Micro-SPECT image acquisition and quantification of sodium-iodide symporter mediated radionuclide accumulation in mouse thyroid and salivary glands.
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ABSTRACT: Background: Micro-SPECT provides a non-invasive way to evaluate the effects of genetic and/or pharmacological modulation on sodium iodide symporter (NIS) mediated radionuclide accumulation in mouse thyroid and salivary glands. However, parameters affecting image acquisition and analysis of mouse thyroids and salivary glands have not been thoroughly investigated. In this study, we investigate the effects of region-of-interest (ROI) selection, collimation, scan time, and imaging orbit on image acquisition and quantification of thyroidal and salivary radionuclide accumulation in mice. Methods: The effects of data window minima and maxima on thyroidal and salivary ROI selection using a visual boundary method was examined in SPECT images acquired from mice injected with I-123 NaI. The effects of collimation, scan time, and imaging orbit on counting linearity and signal intensity was investigated using phantoms filled with various activities of I-123 NaI or Tc-99m pertechnetate. Spatial resolution of target organs in whole animal images was compared between circular orbit with parallel-hole collimation and spiral orbit with five-pinhole collimation. Lastly, the inter-experimental variability of the same mouse scanned multiple times was compared with the intra-experimental variability among different mice scanned at the same time. Results: Separation of thyroid ROI from salivary glands was accomplished by empirically increasing the data window maxima. Counting linearity within the range of 0.5-14.2µCi was validated by phantom imaging using single or multiple collimators with circular or spiral imaging orbit. Scanning time could be shortened to 15 min per mouse without compromising counting linearity despite proportionally decreased signal intensity. Whole-animal imaging using spiral orbit with five-pinhole collimators achieved high spatial resolution and counting linearity. Finally, the extent of inter-experimental variability of NIS-mediated radionuclide accumulation in thyroid and salivary glands by SPECT imaging in the same mouse was less than the magnitude of variability amongst littermates. Conclusions: The impacts of multiple variables and experimental designs on micro-SPECT imaging and quantification of radionuclide accumulation in mouse thyroid and salivary glands can be minimized. This platform will serve as an invaluable tool to screen for pharmacologic reagents that differentially modulate thyroidal and salivary radioiodine accumulation in preclinical mouse models.Thyroid: official journal of the American Thyroid Association 02/2012; · 2.60 Impact Factor -
Article: Modulation of sodium iodide symporter expression and function by LY294002, Akti-1/2 and Rapamycin in thyroid cells.
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ABSTRACT: The selective increase of Na(+)/I(-) symporter (NIS)-mediated active iodide uptake in thyroid cells allows the use of radioiodine I(131) for diagnosis and targeted treatment of thyroid cancers. However, NIS-mediated radioiodine accumulation is often reduced in thyroid cancers due to decreased NIS expression/function. As PI3K signaling is overactivated in many thyroid tumors, we investigated the effects of inhibitors for PI3K, Akt, or mTORC1 as well as their interplay on NIS modulation in thyroid cells under chronic TSH stimulation. PI3K inhibition by LY294002 increased NIS-mediated radioiodide uptake (RAIU) mainly through upregulation of NIS expression, however, mTORC1 inhibition by Rapamycin did not increase NIS-mediated RAIU despite increased NIS protein levels. In comparison, Akt inhibition by Akti-1/2 did not increase NIS protein levels, yet markedly increased NIS-mediated RAIU by decreasing iodide efflux rate and increasing iodide transport rate and iodide affinity of NIS. The effects of Akti-1/2 on NIS-mediated RAIU are not detected in nonthyroid cells, implying that Akti-1/2 or its derivatives may represent potential pharmacological reagents to selectively increase thyroidal radioiodine accumulation and therapeutic efficacy.Endocrine Related Cancer 02/2012; 19(3):291-304. · 4.36 Impact Factor -
Article: Rab23 negatively regulates Gli1 transcriptional factor in a Su(Fu)-dependent manner.
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ABSTRACT: Hedgehog (Hh) signaling, via the key signal transducer Smoothened (SMO) and Gli transcription factors, is essential for embryonic development and carcinogenesis. While the biological relevance of hedgehog signaling to cancer is well established, very little is known about the molecular mechanisms by which signaling transduction of this pathway occurs. Rab23 was discovered as a negative regulator of the Hh pathway through a mouse genetic study. Here we report that Rab23 directly associates with Su(Fu) and inhibits Gli1 function in a Su(Fu)-dependent manner. By confocal microscope and immunoprecipitation, we detected interaction between Rab23 and Su(Fu). Using Gli1-mediated reporter gene analysis, we found that Rab23 can suppress Gli1 transcriptional activity in wild type but not Su(Fu) null fibroblasts. Similarly, Rab23 expression reduced the nuclear localization of Gli1 in wild type but not Su(Fu) null fibroblast cells. Consistent with the GTPase motif in the protein, we showed that Rab23 has GTPase activity. The dominant negative form of Rab23 was unable to suppress Gli1-mediated transcriptional activity. Taken together, these data provide evidence to support that Rab23 negatively regulates Gli1 activity in a Su(Fu)-dependent manner.Cellular signalling 02/2012; 24(6):1222-8. · 4.09 Impact Factor -
Article: Heterogeneous electrochemiluminescence spectrometry of Ru(bpy)3(2+) for determination of trace DNA and its application in measurement of gene expression level.
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ABSTRACT: In this paper, we reported an ultrasensitive ECL spectrometry for determination of DNA using magnetic streptavidin-coated nanobeads MNBs (SA-MNBs) as the carrier of Ru(bpy)(3)(2+)-NHS, where bpy=2,2'-bipyridyl and NHS=N-hydroxysuccinimide ester, to amplify signal. The SA-MNBs were conjugated to the hybrids consisting of capture DNA, target DNA (t-DNA) and probe DNA immobilized on a substrate, followed by releasing the SA-MNBs and binding a huge number of Ru(bpy)(3)(2+)-NHS to the SA-MNBs. The SA-MNBs with Ru(bpy)(3)(2+)-NHS were immobilized on an Au film electrode by means of a magnet. In the presence of tri-n-propylamine, the ECL spectrum of the Ru(bpy)(3)(2+)-NHS at 1.35 V was acquired by using an optical multi-channel analyzer. The maximum emission intensity on the ECL spectrum was used to quantify DNA. Using this method, not only the limit of detection for DNA determination was as low as 1.2 × 10(-15)mol/L, but also the ECL spectrum of Ru(bpy)(3)(2+)-NHS on the surface of the SA-MNBs was obtained. The ultrasensitive ECL spectrometry could be used to measure gene expression level in cells.Talanta 01/2012; 89:427-32. · 3.79 Impact Factor -
Article: The effect of intravitreal anti-VEGF agents on peripheral wound healing in a rabbit model.
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ABSTRACT: To investigate the effect of intravitreal pegaptanib, bevacizumab, and ranibizumab on blood-vessel formation during cutaneous wound healing in a rabbit model and to compare this effect to placebo controls. Forty New Zealand albino rabbits underwent full thickness cutaneous wounds using 6-mm dermatologic punch biopsies. The rabbits were assigned to four groups of ten, each receiving intravitreal injections of pegaptanib, bevacizumab, ranibizumab, or no injection (untreated controls). Five rabbits from each group underwent wound harvesting on day 7 and five from each group on day 14. The skin samples were stained with hematoxylin and eosin (HE), Masson's trichrome (MT), and CD34 for vascular endothelial cells. Semiquantitative evaluation of HE- and MT-stained slides was performed by one pathologist. Quantitative assessment of mean neovascularization (MNV) scores was obtained from five contiguous biopsy margin 400× fields of CD34-stained sections by four independent observers. Week 1 MNV scores in CD-34 stained sections were: untreated controls: 11.51 ± 4.36; bevacizumab: 7.41 ± 2.82 (P = 0.013); ranibizumab: 8.71 ± 4.08 (P = 0.071); and pegaptanib: 10.15 ± 5.59 (P = 0.378). Week 2 MNV data were: untreated controls: 6.14 ± 2.25; bevacizumab: 7.25 ± 2.75 (P = 0.471); ranibizumab: 4.53 ± 3.12 (P = 0.297); and, pegaptanib: 6.35 ± 3.09 (P = 0.892). Interobserver variability using intraclass correlation coefficient was 0.961. At week 1, all three anti-VEGF agents had suppressed MNV scores compared to controls. Although not statistically significant, there was an inhibitory trend, particularly with bevacizumab and ranibizumab. These effects were diminished at 2 weeks, reflecting a transition between the proliferative and remodeling phases of wound healing.Clinical Ophthalmology 01/2012; 6:61-9. -
Article: Lipid storage disorders block lysosomal trafficking by inhibiting a TRP channel and lysosomal calcium release.
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ABSTRACT: Lysosomal lipid accumulation, defects in membrane trafficking and altered Ca(2+) homoeostasis are common features in many lysosomal storage diseases. Mucolipin transient receptor potential channel 1 (TRPML1) is the principle Ca(2+) channel in the lysosome. Here we show that TRPML1-mediated lysosomal Ca(2+) release, measured using a genetically encoded Ca(2+) indicator (GCaMP3) attached directly to TRPML1 and elicited by a potent membrane-permeable synthetic agonist, is dramatically reduced in Niemann-Pick (NP) disease cells. Sphingomyelins (SMs) are plasma membrane lipids that undergo sphingomyelinase (SMase)-mediated hydrolysis in the lysosomes of normal cells, but accumulate distinctively in lysosomes of NP cells. Patch-clamp analyses revealed that TRPML1 channel activity is inhibited by SMs, but potentiated by SMases. In NP-type C cells, increasing TRPML1's expression or activity was sufficient to correct the trafficking defects and reduce lysosome storage and cholesterol accumulation. We propose that abnormal accumulation of luminal lipids causes secondary lysosome storage by blocking TRPML1- and Ca(2+)-dependent lysosomal trafficking.Nature Communications 01/2012; 3:731. · 7.40 Impact Factor -
Article: Propofol prevents autophagic cell death following oxygen and glucose deprivation in PC12 cells and cerebral ischemia-reperfusion injury in rats.
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ABSTRACT: Propofol exerts protective effects on neuronal cells, in part through the inhibition of programmed cell death. Autophagic cell death is a type of programmed cell death that plays elusive roles in controlling neuronal damage and metabolic homeostasis. We therefore studied whether propofol could attenuate the formation of autophagosomes, and if so, whether the inhibition of autophagic cell death mediates the neuroprotective effects observed with propofol. The cell model was established by depriving the cells of oxygen and glucose (OGD) for 6 hours, and the rat model of ischemia was introduced by a transient two-vessel occlusion for 10 minutes. Transmission electron microscopy (TEM) revealed that the formation of autophagosomes and autolysosomes in both neuronal PC12 cells and pyramidal rat hippocampal neurons after respective OGD and ischemia/reperfusion (I/R) insults. A western blot analysis revealed that the autophagy-related proteins, such as microtubule-associated protein 1 light chain 3 (LC3-II), Beclin-1 and class III PI3K, were also increased accordingly, but cytoprotective Bcl-2 protein was decreased. The negative effects of OGD and I/R, including the formation of autophagosomes and autolysosomes, the increase in LC3-II, Beclin-1 and class III PI3K expression and the decline in Bcl-2 production were all inhibited by propofol and specific inhibitors of autophagy, such as 3-methyladenine (3-MA), LY294002 and Bafilomycin A1 (Baf),. Furthermore, in vitro OGD cultures and in vivo I/R rats showed an increase in cell survival following the administration of propofol, as assessed by an MTT assay or histochemical analyses. Our data suggest that propofol can markedly attenuate autophagic processes via the decreased expression of autophagy-related proteins in vitro and in vivo. This inhibition improves cell survival, which provides a novel explanation for the pleiotropic effects of propofol that benefit the nervous system.PLoS ONE 01/2012; 7(4):e35324. · 4.09 Impact Factor -
Article: Functional interactions between starch synthase III and isoamylase-type starch-debranching enzyme in maize endosperm.
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ABSTRACT: This study characterized genetic interactions between the maize (Zea mays) genes dull1 (du1), encoding starch synthase III (SSIII), and isa2, encoding a noncatalytic subunit of heteromeric isoamylase-type starch-debranching enzyme (ISA1/ISA2 heteromer). Mutants lacking ISA2 still possess the ISA1 homomeric enzyme. Eight du1(-) mutations were characterized, and structural changes in amylopectin resulting from each were measured. In every instance, the same complex pattern of alterations in discontinuous spans of chain lengths was observed, which cannot be explained solely by a discrete range of substrates preferred by SSIII. Homozygous double mutants were constructed containing the null mutation isa2-339 and either du1-Ref, encoding a truncated SSIII protein lacking the catalytic domain, or the null allele du1-R4059. In contrast to the single mutant parents, double mutant endosperms affected in both SSIII and ISA2 were starch deficient and accumulated phytoglycogen. This phenotype was previously observed only in maize sugary1 mutants impaired for the catalytic subunit ISA1. ISA1 homomeric enzyme complexes assembled in both double mutants and were enzymatically active in vitro. Thus, SSIII is required for normal starch crystallization and the prevention of phytoglycogen accumulation when the only isoamylase-type debranching activity present is ISA1 homomer, but not in the wild-type condition, when both ISA1 homomer and ISA1/ISA2 heteromer are present. Previous genetic and biochemical analyses showed that SSIII also is required for normal glucan accumulation when the only isoamylase-type debranching enzyme activity present is ISA1/ISA heteromer. These data indicate that isoamylase-type debranching enzyme and SSIII work in a coordinated fashion to repress phytoglycogen accumulation.Plant physiology 12/2011; 158(2):679-92. · 6.53 Impact Factor
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2012
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University of Michigan
- Department of Molecular, Cellular and Developmental Biology
Ann Arbor, MI, USA
-
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2011
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St Joseph Medical Center (MD, USA)
Towson, MD, USA
-
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2009
-
University of Nebraska at Lincoln
- Department of Mechanical and Materials Engineering
Lincoln, NE, USA
-
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2008
-
South China University of Technology
- Department of Electronic Engineering
Guangzhou, Guangdong Sheng, China
-
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2004–2008
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Iowa State University
Ames, IA, USA
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