Min-Jung Lee

Yonsei University, Seoul, Seoul, South Korea

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Publications (32)115.41 Total impact

  • Article: Expression of miR-206 during the initiation of mammary gland development.
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    ABSTRACT: MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting mRNAs and triggering either translational repression or RNA degradation. The aberrant expression of miRNAs might be involved in human diseases, including cancer. The expression of miR-206 in estrogen receptor alpha (ER-α)-positive human breast cancer tissues is well known. However, the expression and regulation of miR-206 in the developing mammary gland has not yet been studied. To understand the effects of miR-206 on mammary gland development, we have profiled gene expression in scramble-transfected and miR-206-overexpressing developing mammary buds. The genes that are potentially regulated by miR-206 in the mammary epithelium and/or mesenchyme, such as Tachykinin1 and Gata3, are known to be breast cancer markers. The expression of Wnt, which is involved in gland positioning, and of the transcription factors Tbx3 and Lef1, which are essential for mammary gland development, changes after miR-206 overexpression. Using a mammary bud in vitro culture system, we have demonstrated that miR-206 acts downstream of ER-α during mammary gland growth. Thus, miR-206 might be a novel candidate for morphogenesis during the initiation of mammary gland formation and the regulation of genes related to mammary gland development and breast cancer.
    Cell and Tissue Research 06/2013; · 3.11 Impact Factor
  • Article: Spartin Regulates Synaptic Growth and Neuronal Survival by Inhibiting BMP-Mediated Microtubule Stabilization.
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    ABSTRACT: Troyer syndrome is a hereditary spastic paraplegia caused by human spartin (SPG20) gene mutations. We have generated a Drosophila disease model showing that Spartin functions presynaptically with endocytic adaptor Eps15 to regulate synaptic growth and function. Spartin inhibits bone morphogenetic protein (BMP) signaling by promoting endocytic degradation of BMP receptor wishful thinking (Wit). Drosophila fragile X mental retardation protein (dFMRP) and Futsch/MAP1B are downstream effectors of Spartin and BMP signaling in regulating microtubule stability and synaptic growth. Loss of Spartin or elevation of BMP signaling induces age-dependent progressive defects resembling hereditary spastic paraplegias, including motor dysfunction and brain neurodegeneration. Null spartin phenotypes are prevented by administration of the microtubule-destabilizing drug vinblastine. Together, these results demonstrate that Spartin regulates both synaptic development and neuronal survival by controlling microtubule stability via the BMP-dFMRP-Futsch pathway, suggesting that impaired regulation of microtubule stability is a core pathogenic component in Troyer syndrome.
    Neuron 02/2013; 77(4):680-95. · 14.74 Impact Factor
  • Article: Comprehensive Genome-Wide Proteomic Analysis of Human Placental Tissue for the Chromosome-Centric Human Proteome Project.
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    ABSTRACT: As a starting point of the Chromosome-Centric Human Proteome Project (C-HPP), we established strategies of genome-wide proteomic analysis, including protein identification, quantitation of disease-specific proteins, and assessment of post-translational modifications, using paired human placental tissues from healthy and preeclampsia patients. This analysis resulted in identification of 4,239 unique proteins with high confidence (two or more unique peptides with a false discovery rate less than 1%), covering 20.88% of approximately 20,059 (Ensembl v69, Oct 2012) human proteins, among which 28 proteins exhibited differentially expressed preeclampsia-specific proteins. When these proteins are assigned to all human chromosomes, the pattern of the newly identified placental protein population is proportional to that of the gene count distribution of each chromosome. We also identified 219 unique N-linked glycopeptides, 592 unique phosphopeptides, and 66 chromosome 13-specific proteins. In particular, protein evidence of 14 genes previously known to be specifically up-regulated in human placenta was verified by mass spectrometry. With respect to the functional implication of these proteins, 38 proteins were found to be involved in regulatory factor biosynthesis or the immune system in the placenta, but the molecular mechanism of these proteins during pregnancy warrants further investigation. As far as we know, this work produced the highest number of proteins identified in the placenta and will be useful for annotating and mapping all proteins encoded in the human genome.
    Journal of Proteome Research 01/2013; · 5.11 Impact Factor
  • Article: Human liver carboxylesterase 1 outperforms alpha-fetoprotein as biomarker to discriminate hepatocellular carcinoma from other liver diseases in Korean patients.
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    ABSTRACT: Although alpha-fetoprotein is currently the major serologic biomarker for hepatocellular carcinoma (HCC), it cannot efficiently distinguish this cancer from other forms of liver disease in early diagnosis due to its low sensitivity. The aim of this study is to compare human carboxylesterase 1 (hCE1) biomarker sensitivity and specificity versus alpha-fetoprotein (AFP). Antibody-based assays for hCE1 and AFP were used to test both biomarkers with respect to diagnostic efficiency, Youden's index, and the area under the curve (AUC) through receiver operating characteristic (ROC) analysis in plasma from 208 patients with HCC (n=57), liver cirrhosis (n=27), chronic hepatitis (n=37), cholangiocarcinoma (n=22), gastric cancer (n=31), and pancreatic cancer (n=34), along with 52 healthy donors. The levels of hCE1 were significantly higher in patients with HCC than healthy donors and the other diseases (p < 0.005), further verified by AUC values and Youden's index. In the set of HCC versus liver cirrhosis the AUC values were 0.744 (AFP), 0.918 (hCE1), and 0.938 (combination of AFP and hCE1), respectively. These results indicate that hCE1 is not only a more potent and specific marker in distinguishing cancer from liver diseases, in particular cirrhosis, but the combination of hCE1 and AFP shows also synergistic potential for greater sensitivity and specificity in early diagnosis. Therefore the antibody-based hCE1 assay appears to have high diagnostic efficiency for discriminating HCC from other forms of liver disease. It is now feasible to further validate this novel plasma-based biomarker in the large cohort we assembled. © 2013 Wiley Periodicals, Inc.
    International Journal of Cancer 01/2013; · 5.44 Impact Factor
  • Article: Korean Red Ginseng Extract Attenuates 3-Nitropropionic Acid-Induced Huntington's-Like Symptoms.
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    ABSTRACT: Korean red ginseng (KRG) possesses neuroprotective activity. However, the potential neuroprotective value of KRG for the striatal toxicity is largely unknown. We investigated whether KRG extract (KRGE) could have a neuroprotective effect in a 3-nitropropionic acid- (3-NP) induced (i.p.) Huntington's disease (HD) model. KRGE (50, 100, and 250 mg/kg/day, p.o.) was administrated 10 days before 3-NP injection (pre-administration), from the same time with 3-NP injection (co-administration), or from the peak point of neurological impairment by 3-NP injection (post-administration). Pre-administration of KRGE produced the greatest neuroprotective effect in this model. Pre-administration of KRGE significantly decreased 3-NP-induced neurological impairment, lethality, lesion area, and neuronal loss in the 3-NP-injected striatum. KRGE attenuated microglial activation and phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signal pathway. KRGE also reduced the level of mRNA expression of tumor necrosis factor-alpha, interleukin- (IL-) 1β, IL-6, inducible nitric oxide synthase, and OX-42. Interestingly, the intrathecal administration of SB203580 (a p38 inhibitor) or PD98059 (an inhibitor of MAPK Kinase, MEK) increased the survival rate in the 3-NP-induced HD model. Pre-administration of KRGE may effectively inhibit 3-NP-induced striatal toxicity via the inhibition of the phosphorylation of MAPKs and NF-κB pathways, indicating its therapeutic potential for suppressing Huntington's-like symptoms.
    Evidence-based Complementary and Alternative Medicine 01/2013; 2013:237207. · 4.77 Impact Factor
  • Article: Ihh and runx2/runx3 signaling interact to coordinate early chondrogenesis: a mouse model.
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    ABSTRACT: Endochondral bone formation begins with the development of a cartilage intermediate that is subsequently replaced by calcified bone. The mechanisms occurring during early chondrogenesis that control both mesenchymal cell differentiation into chondrocytes and cell proliferation are not clearly understood in vertebrates. Indian hedgehog (Ihh), one of the hedgehog signaling molecules, is known to control both the hypertrophy of chondrocytes and bone replacement; these processes are particularly important in postnatal endochondral bone formation rather than in early chondrogenesis. In this study, we utilized the maternal transfer of 5E1 to E12.5 in mouse embryos, a process that leads to an attenuation of Ihh activity. As a result, mouse limb bud chondrogenesis was inhibited, and an exogenous recombinant IHH protein enhanced the proliferation and differentiation of mesenchymal cells. Analysis of the genetic relationships in the limb buds suggested a more extensive role for Ihh and Runx genes in early chondrogenesis. The transfer of 5E1 decreased the expression of Runx2 and Runx3, whereas an exogenous recombinant IHH protein increased Runx2 and Runx3 expression. Moreover, a transcription factor Gli1 in hedgehog pathway enhances the direct induction of both Runx2 and Runx3 transcription. These findings suggested that Ihh signaling plays an important role in chondrocyte proliferation and differentiation via interactions with Runx2 and Runx3.
    PLoS ONE 01/2013; 8(2):e55296. · 4.09 Impact Factor
  • Article: GenomewidePDB, a Proteomic Database Exploring the Comprehensive Protein Parts List and Transcriptome Landscape in Human Chromosomes.
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    ABSTRACT: In an effort to map the human proteome, the Chromosome-centric Human Proteome Project (C-HPP) was recently initiated. As a member of the international consortium working on this project, our laboratory developed a gene-centric proteomic database called GenomewidePDB, which integrates proteomic data for proteins encoded by chromosomes with transcriptomic data and other information from public databases. As an example case, we chose chromosome 13, which is the largest acrocentric human chromosome with the lowest gene density and contains 326 predicted proteins. All proteins stored in GenomewidePDB are linked to other resources, including neXtProt and Ensembl for protein and gene information, respectively. The Global Proteome Machine database (GPMdb) and the PeptideAtlas are also accessed for observed mass spectrometry (MS) information, while Human Protein Atlas is used for information regarding antibody availability and tissue expression, respectively. Gene ontology disease information is also included. As a pilot work, we constructed this GenomewidePDB with the identified 3615 proteins including 53 chromosome 13-origin proteins that are present in normal human placenta tissue. Thus, developing a comprehensive database containing actual experimental proteomics data will provide a valuable resource for cross chromosomal comparison in the C-HPP community.
    Journal of Proteome Research 12/2012; · 5.11 Impact Factor
  • Article: Ethyl pyruvate attenuates formalin-induced inflammatory nociception by inhibiting neuronal ERK phosphorylation.
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    ABSTRACT: Ethyl pyruvate (EP) possesses anti-inflammatory activity. However, the potential anti-nociceptive value of EP for the treatment of the inflammatory nociception is largely unknown. We investigated whether EP could have any anti-nociceptive effect on inflammatory pain, after systemic administration of EP (10, 50, and 100 mg/kg, i.p.), 1 hour before formalin (5%, 50 μl) injection into the plantar surface of the hind paws of rats. EP significantly decreased formalin-induced nociceptive behavior during phase II, the magnitude of paw edema, and the activation of c-Fos in L4-L5 spinal dorsal horn. EP also attenuated the phosphorylation of extracellular signal-regulated kinase (ERK) in the neurons of L4-L5 spinal dorsal horn after formalin injection. Interestingly, the i.t. administration of PD98059, an ERK upstream kinase (MEK) inhibitor, completely blocked the formalin-induced inflammatory nociceptive responses. These results demonstrate that EP may effectively inhibit formalin-induced inflammatory nociception via the inhibition of neuronal ERK phosphorylation in the spinal dorsal horn, indicating its therapeutic potential in suppressing acute inflammatory pain.
    Molecular Pain 05/2012; 8:40. · 3.53 Impact Factor
  • Article: Association of Shh and Ptc with keratin localization in the initiation of the formation of circumvallate papilla and von Ebner’s gland
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    ABSTRACT: The development of gustatory papillae in mammalian embryos requires the coordination of a series of morphological events, such as proliferation, differentiation and innervation. In mice, the circumvallate papilla (CVP) is a specialized structure that develops in a characteristic spatial and temporal pattern in the posterior region of the tongue dorsal surface. The distinct expression patterns of Shh and Ptc, which play important roles in the development of other epithelial appendages, have been localized in the trench wall that gives rise to von Ebner’s gland (VEG). To define the cellular mechanisms responsible for morphogenesis and differentiation during early development of CVP and VEG, the localization patterns of keratins (cytokeratins) K7, K8, K18, K19, K14 and connexin-43, which are dependent on Shh expression in other developmental systems, have been examined in detail. The distinct localization of keratins K7, K8, K18, K19, K14 and connexin-43 in the epithelium giving rise to the CVP and VEG suggests that cytodifferentiation is established prior to morphological changes. Interestingly, the localization of proliferating cell nuclear antigen, a marker for cell proliferation, is similar to that of Shh. An understanding of the regulatory roles of cell-cell interactions and signalling molecules in orchestrating a mutual network will bring us nearer to defining the molecular and cellular mechanisms underlying morphogenesis in mammalian taste bud development.
    Cell and Tissue Research 04/2012; 325(2):253-261. · 3.11 Impact Factor
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    Article: Minocycline markedly reduces acute visceral nociception via inhibiting neuronal ERK phosphorylation.
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    ABSTRACT: Minocycline prevents the development of neuropathic and inflammatory pain by inhibiting microglial activation and postsynaptic currents. But, how minocycline obviates acute visceral pain is unclear. The present study investigated whether minocycline had an any antinociceptive effect on acetic acid-induced acute abdominal pain after intraperitoneal (i.p.) administration of saline or minocycline 1 hour before acetic acid injection (1.0%, 250 μl, i.p.). Minocycline (4, 10, or 40 mg/kg) significantly decreased acetic acid-induced nociception (0-60 minutes post-injection) and the enhancement in the number of c-Fos positive cells in the T5-L2 spinal cord induced by acetic acid injection. Also, the expression of spinal phosphorylated extracellular signal-regulated kinase (p-ERK) induced by acetic acid was reduced by minocycline pre-administration. Interestingly, intrathecal introduction of PD98059, an ERK upstream kinase inhibitor, markedly blocked the acetic acid-stimulated pain responses. These results demonstrate that minocycline effectively inhibits acetic acid-induced acute abdominal nociception via the inhibition of neuronal p-ERK expression in the spinal cord, and that minocycline may have therapeutic potential in suppressing acute abdominal pain.
    Molecular Pain 02/2012; 8:13. · 3.53 Impact Factor
  • Article: Differential gel-based proteomic approach for cancer biomarker discovery using human plasma.
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    ABSTRACT: Two-dimensional fluorescence difference gel electrophoresis (2D DIGE) has become a general platform for analysis of various clinical samples such as biofluids and tissues. In comparison to conventional 2-D polyacrylamide gel electrophoresis (2D PAGE), 2D DIGE offers several advantages, such as accuracy and reproducibility between experiments, which facilitate spot-to-spot comparisons. Although whole plasma can be easily obtained, the complexity of plasma samples makes it challenging to analyze samples with good reproducibility. Here, we describe a method for decreasing protein complexity in plasma samples within a narrow pH range by depleting high-abundance plasma proteins. In combination with analysis of differentially expressed spots, trypsin digestion, identification of protein by mass spectrometry, and standard 2D PAGE and DIGE, this method has been optimized for comparison of plasma samples from healthy donors and patients diagnosed with hepatocellular carcinoma.
    Methods in molecular biology (Clifton, N.J.) 01/2012; 854:223-37.
  • Article: MiR-200b is involved in Tgf-β signaling to regulate mammalian palate development.
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    ABSTRACT: Various cellular and molecular events are involved in palatogenesis, including apoptosis, epithelial-mesenchymal transition (EMT), cell proliferation, and cell migration. Smad2 and Snail, which are well-known key mediators of the transforming growth factor beta (Tgf-β) pathway, play a crucial role in the regulation of palate development. Regulatory effects of microRNA 200b (miR-200b) on Smad2 and Snail in palatogenesis have not yet been elucidated. The aim of this study is to determine the relationship between palate development regulators miR-200b and Tgf-β-mediated genes. Expression of miR-200b, E-cadherin, Smad2, and Snail was detected in the mesenchyme of the mouse palate, while miR-200b was expressed in the medial edge epithelium (MEE) and palatal mesenchyme. After the contact of palatal shelves, miR-200b was no longer expressed in the mesenchyme around the fusion region. The binding activity of miR-200b to both Smad2 and Snail was examined using a luciferase assay. MiR-200b directly targeted Smad2 and Snail at both cellular and molecular levels. The function of miR-200b was determined by overexpression via a lentiviral vector in the palatal shelves. Ectopic expression of miR-200b resulted in suppression of these Tgf-β-mediated regulators and changes of apoptosis and cell proliferation in the palatal fusion region. These results suggest that miR-200b plays a crucial role in regulating the Smad2, Snail, and in apoptosis during palatogenesis by acting as a direct non-coding, influencing factor. Furthermore, the molecular interactions between miR-200b and Tgf-β signaling are important for proper palatogenesis and especially for palate fusion. Elucidating the mechanism of palatogenesis may aid the design of effective gene-based therapies for the treatment of congenital cleft palate.
    Histochemie 11/2011; 137(1):67-78. · 2.59 Impact Factor
  • Article: Retinoic acid modulates chondrogenesis in the developing mouse cranial base.
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    ABSTRACT: The retinoic acid (RA) signaling pathway is known to play important roles during craniofacial development and skeletogenesis. However, the specific mechanism involving RA in cranial base development has not yet been clearly described. This study investigated how RA modulates endochondral bone development of the cranial base by monitoring the RA receptor RARγ, BMP4, and markers of proliferation, programmed cell death, chondrogenesis, and osteogenesis. We first examined the dynamic morphological and molecular changes in the sphenooccipital synchondrosis-forming region in the mouse embryo cranial bases at E12-E16. In vitro organ cultures employing beads soaked in RA and retinoid-signaling inhibitor citral were compared. In the RA study, the sphenooccipital synchondrosis showed reduced cartilage matrix and lower BMP4 expression while hypertrophic chondrocytes were replaced with proliferating chondrocytes. Retardation of chondrocyte hypertrophy was exhibited in citral-treated specimens, while BMP4 expression was slightly increased and programmed cell death was induced within the sphenooccipital synchondrosis. Our results demonstrate that RA modulates chondrocytes to proliferate, differentiate, or undergo programmed cell death during endochondral bone formation in the developing cranial base.
    Journal of Experimental Zoology Part B Molecular and Developmental Evolution 08/2011; 316(8):574-83. · 2.42 Impact Factor
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    Article: Interactions between Shh, Sostdc1 and Wnt signaling and a new feedback loop for spatial patterning of the teeth.
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    ABSTRACT: Each vertebrate species displays specific tooth patterns in each quadrant of the jaw: the mouse has one incisor and three molars, which develop at precise locations and at different times. The reason why multiple teeth form in the jaw of vertebrates and the way in which they develop separately from each other have been extensively studied, but the genetic mechanism governing the spatial patterning of teeth still remains to be elucidated. Sonic hedgehog (Shh) is one of the key signaling molecules involved in the spatial patterning of teeth and other ectodermal organs such as hair, vibrissae and feathers. Sostdc1, a secreted inhibitor of the Wnt and Bmp pathways, also regulates the spatial patterning of teeth and hair. Here, by utilizing maternal transfer of 5E1 (an anti-Shh antibody) to mouse embryos through the placenta, we show that Sostdc1 is downstream of Shh signaling and suggest a Wnt-Shh-Sostdc1 negative feedback loop as a pivotal mechanism controlling the spatial patterning of teeth. Furthermore, we propose a new reaction-diffusion model in which Wnt, Shh and Sostdc1 act as the activator, mediator and inhibitor, respectively, and confirm that such interactions can generate the tooth pattern of a wild-type mouse and can explain the various tooth patterns produced experimentally.
    Development 03/2011; 138(9):1807-16. · 6.60 Impact Factor
  • Article: Identification and characterization of adenovirus early region 1B-associated protein 5 as a surface marker on undifferentiated human embryonic stem cells.
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    ABSTRACT: Pluripotent human embryonic stem cells (hESCs) provide appropriate systems for developmental studies and prospective donor cell sources for regenerative medicine. Identification of surface markers specific to hESCs is a prerequisite for studying hESC biology and can be used to generate clinical-level donor cell preparations that are free from tumorigenic undifferentiated hESCs. We previously reported the generation of monoclonal antibodies that specifically recognize hESC surface antigens using a decoy immunization strategy. In this study, we show that monoclonal antibody 57-C11 recognizes a phosphorylated form of adenovirus early region 1B-associated protein 5 (E1B-AP5). E1B-AP5 is a nuclear RNA-binding protein, but we report that 57-C11-reactive E1B-AP5 is expressed on the surface of undifferentiated hESCs. In undifferentiated hESCs, 57-C11-reactive E1B-AP5 is localized to SSEA3-, SSEA4-, TRA-1-60-, TRA-1-81-, OCT4-, SOX2-, and NANOG-positive hESCs. In mixtures of undifferentiated hESCs and hESC-derived neurons, 57-C11 exclusively recognizes undifferentiated hESCs but not hESC-derived neuronal cells. Further, the expression of 57-C11-reactive E1B-AP5 decreases upon differentiation. Our results demonstrate that 57-C11-reactive E1B-AP5 is a novel surface molecule that is involved in the undifferentiated state of hESCs. As far as we know, this is the first report demonstrating that heterogeneous nuclear RNA-binding protein is expressed on the surface of undifferentiated hESCs.
    Stem cells and development 11/2010; 20(4):609-20. · 4.15 Impact Factor
  • Article: Function analysis of mesenchymal Bcor in tooth development by using RNA interference.
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    ABSTRACT: Teeth, an excellent model for studying organogenesis, develop from a series of epithelial-mesenchymal interactions that are mediated by a complex molecular network. Bcor (BCL-6 interacting corepressor) has recently been discovered, but little is known about its function in tooth development. Mutations in BCOR affect humans with oculofaciocardiodental syndrome, which is an X-linked dominant disorder with presumed male lethality and which comprises microphthalmia, congenital cataracts, radiculomegaly, and cardiac and digital abnormalities. In this study, the Bcor expression pattern has been intensively investigated during mouse molar development. Bcor is expressed in both dental epithelium and the mesenchyme at E11.5. To understand the function of Bcor, knockdown of Bcor has been examined by using lentivirus-mediated RNA interference. Silencing of Bcor expression in dental mesenchymal cells at E14.5 causes dentinogenesis defects and retardation of tooth root development. Thus, our results suggest that Bcor expressed in the mesenchyme plays crucial roles during early tooth development. The function of Bcor expressed in the epithelium remains to be elucidated.
    Cell and Tissue Research 08/2010; 341(2):251-8. · 3.11 Impact Factor
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    Article: Effects of hyaluronan on carrageenan-induced synovitis in rat TMJ.
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    ABSTRACT: Nitric oxide is one of many proinflammatory mediators that are involved in temporomandibular joint (TMJ) inflammatory disorder and is synthesized by inducible nitric oxide synthase (iNOS). iNOS is transcriptionally regulated by nuclear factor-κB (NF-κB) in cases of inflammation, proliferation, and apoptosis. It has also been reported that nitric oxide is positively regulated by carrageenan and negatively regulated by hyaluronan in the knee joint. The aim of this study was to histologically evaluate how inflammation and cell proliferation of the synovial membrane are affected by the exogenous administration of carrageenan and hyaluronan in the rat TMJ by investigating iNOS, NF-κB, and anti proliferating cell nuclear antigen (PCNA) immunoreactivity. As results, immunoreactive cells to iNOS, NF-κB, and PCNA were normally localized only in the synovial membrane of wild type TMJs. The numbers of immunoreactive cells were extensively larger in the carrageenan-injected synovial membranes exhibiting excessive folding, and smaller in the hyaluronan-injected synovial membranes showing a few folds. These results indicate that a carrageenan injection induced inflammation and cell proliferation especially in the synovial membrane and that hyaluronan relieved the inflammation by decreasing inflammatory molecules in the synovial membrane.
    Anatomy & cell biology 06/2010; 43(2):125-31.
  • Article: Characteristics of ethylnitrosourea-induced cataracts.
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    ABSTRACT: This study analyzed genes associated with the morphology and regulation of ethylnitrosourea (ENU)-induced cataract mouse. Immunohistochemistry analysis using anti-crystallins and PCNA antibody revealed that the localization pattern of these specific markers differed between the cataractous and wild-type lens epithelium. Two-dimensional electrophoresis and microarray techniques were used to identify the proteins and genes related to ENU-induced cataract. A novel ENU-induced mutation in the mouse led to nuclear and cortical opacity of the eye lens at 5 weeks postnatal. This cataract phenotype was similar to that of the zonular-pulverulent type of human cataract. Crystallin proteins and gap-junction genes have relations to the formation of cataract. Together, the results suggest that various proteins affect the formation and specific phenotypes of ENU-induced cataract mouse.
    Current eye research 06/2009; 34(5):360-8. · 1.51 Impact Factor
  • Article: Drosophila Atlastin regulates the stability of muscle microtubules and is required for synapse development.
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    ABSTRACT: Hereditary spastic paraplegia (HSP) is an inherited neurological disorder characterized by progressive spasticity and weakness of the lower extremities. The most common early-onset form of HSP is caused by mutations in the human gene that encodes the dynamin-family GTPase Atlastin-1 (Atl-1). Recently, loss of the Drosophila ortholog of Atl-1 (Atl) has been found to induce locomotor impairments from the earliest adult stages, suggesting the developmental role of atlastin-subfamily GTPases. Here, we provide evidence that Atl is required for normal growth of muscles and synapses at the neuromuscular junction (NMJ). Atl protein is highly expressed in larval body-wall muscles. Loss-of-function mutations in the atl gene reduce the size of muscles and increase the number of synaptic boutons. Rescue of these defects is accomplished by muscular, but not neuronal expression of Atl. Loss of Atl also disrupts ER and Golgi morphogenesis in muscles and reduces the synaptic levels of the scaffold proteins Dlg and alpha-spectrin. We also provide evidence that Atl functions with the microtubule-severing protein Spastin to disassemble microtubules in muscles. Finally, we demonstrate that the microtubule-destabilizing drug vinblastine alleviates synapse and muscle defects in atl mutants. Together, our results suggest that Atl controls synapse development and ER and Golgi morphogenesis by regulating microtubule stability.
    Developmental Biology 04/2009; 330(2):250-62. · 4.07 Impact Factor
  • Article: MAPK mediates Hsp25 signaling in incisor development.
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    ABSTRACT: Rodent incisors are continuously growing teeth that include all stages of amelogenesis. Understanding amelogenesis requires investigations of the genes and their gene products control the ameloblast phenotype. One of the mechanisms related to tooth differentiation is mitogen-activated protein kinase (MAPK) signaling. The extracellular-signal regulated kinase (ERK)/mitogen-activated protein kinase kinase (MEK) cascade is associated with mechanisms that control the cell cycle and cell survival. However, the roles of cascades in incisor development remain to be determined. In this study, we investigated incisor development and growth in the mouse based on MAPK signaling. Moreover, heat-shock protein (Hsp)-25 is well known to be a useful marker of odontoblast differentiation. We used anisomycin (a protein-synthesis inhibitor that activates MAPKs) and U0126 (a MAPK inhibitor that blocks ERK1/2 phosphorylation) to examine the role of MAPKs in Hsp25 signaling in the development of the mouse incisor. We performed immunohistochemistry and in vitro culture using incisor tooth germ, and found that phospho-ERK (pERK), pMEK, and Hsp25 localized in developing incisor ameloblasts and anisomycin failed to produce incisor development. In addition, Western blotting results showed that anisomycin stimulated the phosphorylation of ERK, MEK, and Hsp25, and that some of these proteins were blocked by the U0126. These findings suggest that MAPK signals play important roles in incisor formation, differentiation, and development by mediating Hsp25 signaling.
    Histochemie 03/2009; 131(5):593-603. · 2.59 Impact Factor

Institutions

  • 2005–2013
    • Yonsei University
      • • Department of Oral Biology
      • • Yonsei Proteome Research Center
      • • Department of Anatomy
      Seoul, Seoul, South Korea
  • 2007–2008
    • Kyungpook National University
      • School of Dentistry
      Sangju, North Gyeongsang, South Korea