• Title/Summary/Keyword: Beta cell function

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Involvement of Corticotropin-releasing Factor Receptor 2β in Differentiation of Dopaminergic MN9D Cells

  • Jin, Tae-Eun;Jang, Miae;Kim, Hyunjung;Choi, Yu Mi;Cho, Hana;Chung, Sungkwon;Park, Myoung Kyu
    • Molecules and Cells
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    • v.26 no.3
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    • pp.243-249
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    • 2008
  • Corticotropin releasing factor (CRF) mediates various responses to stress through CRF receptors 1 and 2. CRF receptor 2 has two forms, $2{\alpha}$ and $2{\beta}$ each of which appears to have distinct roles. Here we used dopaminergic neuron-derived MN9D cells to investigate the function of CRF receptor 2 in dopamine neurons. We found that n-butyrate, a histone deacetylase inhibitor, induced MN9D cell differentiation and increased gene expression of all CRF receptors. CRF receptor $2{\beta}$ was minimally expressed in MN9D cells; however, its expression dramatically increased during differentiation. CRF receptor $2{\beta}$ expression levels appeared to correlate with neurite outgrowth, suggesting CRF receptor $2{\beta}$ involvement in neuronal differentiation. To validate this statement, we made a CRF receptor $2{\beta}$-overexpressing $MN9D/CRFR2{\beta}$ stable cell line. This cell line showed robust neurite outgrowth and GAP43 overexpression, together with MEK and ERK activation, suggesting MN9D cell neuronal differentiation. From these results, we conclude that CRF receptor $2{\beta}$ plays an important role in MN9D cell differentiation by activating the MEK/ERK signaling pathway.

Effects of Conjugated Linoleic Acid and Stearic Acid on Apoptosis of the INS-1 β-cells and Pancreatic Islets Isolated from Zucker Obese (fa/fa) Rats

  • Jang, I.S.;Hwang, D.Y.;Lee, J.E.;Kim, Y.K.;Kang, T.S.;Hwang, J.H.;Lim, C.H.;Chae, K.R.;Jeong, J.H.;Cho, J.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.7
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    • pp.1060-1065
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    • 2003
  • To determine whether dietary fatty acids affect pancreatic $\beta$-cell function, the INS-1 $\beta$-cells and the pancreatic islets isolated from Zucker obese (fa/fa) rats were cultured with stearic acid and conjugated linoleic acid (CLA). As a result, DNA fragmentation laddering was substantially decreased in the INS-1 $\beta$-cells and the isolated pancreatic islets cultured with 2 mM CLA compared to those cultured with stearic acid. To investigate the mechanism by which CLA alleviates cell apoptosis under DNA fragmentation assay, we examined mRNA expressions of apoptosis-related proteins including Bax and Bcl-2 associated with cell death agonist and antagonist, respectively, in both INS-1 cells and islets cultured with 2 mM fatty acids. Bax mRNA expression was not altered by either stearic acid or CLA, whereas Bcl-2 mRNA expression was enhanced by CLA when compared to the stearic acid cultures. However, there were no changes in cell apoptosis and apoptotic-regulating gene products in either INS-1 cells or isolated islets treated with or without 2 mM CLA. It is concluded that CLA maintains $\beta$-cell viability via increased Bcl-2 expression compared to the stearic acid cultures, which may help to alleviate, at least somewhat, the onset of NIDDM in the physiological status. More detailed study is still needed to elucidate the effect of CLA on the prevention of fatty acid-induced $\beta$-cell apoptosis.

Transforming growth factor β1 enhances adhesion of endometrial cells to mesothelium by regulating integrin expression

  • Choi, Hee-Jung;Park, Mi-Ju;Kim, Bo-Sung;Choi, Hee-Jin;Joo, Bosun;Lee, Kyu Sup;Choi, Jung-Hye;Chung, Tae-Wook;Ha, Ki-Tae
    • BMB Reports
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    • v.50 no.8
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    • pp.429-434
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    • 2017
  • Endometriosis is the abnormal growth of endometrial cells outside the uterus, causing pelvic pain and infertility. Furthermore, adhesion of endometrial tissue fragments to pelvic mesothelium is required for the initial step of endometriosis formation outside uterus. $TGF-{\beta}1$ and adhesion molecules importantly function for adhesion of endometrial tissue fragments to mesothelium outside uterus. However, the function of $TGF-{\beta}1$ on the regulation of adhesion molecule expression for adhesion of endometrial tissue fragments to mesothelium has not been fully elucidated. Interestingly, transforming growth factor ${\beta}1$ ($TGF-{\beta}1$) expression was higher in endometriotic epithelial cells than in normal endometrial cells. The adhesion efficiency of endometriotic epithelial cells to mesothelial cells was also higher than that of normal endometrial cells. Moreover, $TGF-{\beta}1$ directly induced the adhesion of endometrial cells to mesothelial cells through the regulation of integrin of ${\alpha}V$, ${\alpha}6$, ${\beta}1$, and ${\beta}4$ via the activation of the $TGF-{\beta}1/TGF-{\beta}RI/Smad2$ signaling pathway. Conversely, the adhesion of $TGF-{\beta}1-stimulated$ endometrial cells to mesothelial cells was clearly reduced following treatment with neutralizing antibodies against specific $TGF-{\beta}1-mediated$ integrins ${\alpha}V$, ${\beta}1$, and ${\beta}4$ on the endometrial cell membrane. Taken together, these results suggest that $TGF-{\beta}1$ may act to promote the initiation of endometriosis by enhancing integrin-mediated cell-cell adhesion.

EXPRESSION OF E-CADHERIN AND ${\beta}-CATENIN$ IN RELATION TO CLINICOPATHOLOGIC FEATURES IN ORAL SQUAMOUS CELL CARCINOMA (구강 편평세포암종에서 E-cadherin과 ${\beta}-catenin$의 발현과 임상병리학적 특징)

  • Pyo, Sung-Woon;Lee, Kwang-Bae;Kim, Young-Sill;Lee, Sang-Hwa
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.28 no.5
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    • pp.396-403
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    • 2006
  • Changes in cell adhesion molecules are associated with infiltration and metastatic progression of cancer. Reduced expression of E-cadherin and ${\beta}-catenin$ complex in some carcinomas has been reported. The changes in the expression in oral squamous cell carcinoma (OSCC) is not fully understood and it also remains undetermined whether the expression of these adhesion molecules in metastatic lesions differs from that in the primary lesions. In the present study, therefore, we immunohistochemically examined the expression of E-cadherin and ${\beta}-catenin$ in 45 primary OSCCs and 19 metastatic lymph nodes. We compared the expression of these molecules between primary and metastatic lesions and investigated the correlation between the expression and clinicopathologic parameters. The expression of E-cadherin and ${\beta}-catenin$ was reduced in 35/45 (78.2%), 14/45 (31.2%) of primary tumors respectively, but 18/19 (94.7%) and 17/19 (89.4%) of lymph nodes showed preserved expression. The reduced expression of the E-cadherin was associated with lymph node metastasis, invasive mode and marginal status but no significant relationship was not found with ${\beta}-catenin$. In conclusion, the loss of E-cadherin and ${\beta}-catenin$ complex function is associated with progression of OSCC and suggest that the expression of this complex will be a supplementary prognostic tool.

Increased Cellular NAD+ Level through NQO1 Enzymatic Action Has Protective Effects on Bleomycin-Induced Lung Fibrosis in Mice

  • Oh, Gi-Su;Lee, Su-Bin;Karna, Anjani;Kim, Hyung-Jin;Shen, AiHua;Pandit, Arpana;Lee, SeungHoon;Yang, Sei-Hoon;So, Hong-Seob
    • Tuberculosis and Respiratory Diseases
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    • v.79 no.4
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    • pp.257-266
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    • 2016
  • Background: Idiopathic pulmonary fibrosis is a common interstitial lung disease; it is a chronic, progressive, and fatal lung disease of unknown etiology. Over the last two decades, knowledge about the underlying mechanisms of pulmonary fibrosis has improved markedly and facilitated the identification of potential targets for novel therapies. However, despite the large number of antifibrotic drugs being described in experimental pre-clinical studies, the translation of these findings into clinical practices has not been accomplished yet. NADH:quinone oxidoreductase 1 (NQO1) is a homodimeric enzyme that catalyzes the oxidation of NADH to $NAD^+$ by various quinones and thereby elevates the intracellular $NAD^+$ levels. In this study, we examined the effect of increase in cellular $NAD^+$ levels on bleomycin-induced lung fibrosis in mice. Methods: C57BL/6 mice were treated with intratracheal instillation of bleomycin. The mice were orally administered with ${\beta}$-lapachone from 3 days before exposure to bleomycin to 1-3 weeks after exposure to bleomycin. Bronchoalveolar lavage fluid (BALF) was collected for analyzing the infiltration of immune cells. In vitro, A549 cells were treated with transforming growth factor ${\beta}1$ (TGF-${\beta}1$) and ${\beta}$-lapachone to analyze the extracellular matrix (ECM) and epithelial-mesenchymal transition (EMT). Results: ${\beta}$-Lapachone strongly attenuated bleomycin-induced lung inflammation and fibrosis, characterized by histological staining, infiltrated immune cells in BALF, inflammatory cytokines, fibrotic score, and TGF-${\beta}1$, ${\alpha}$-smooth muscle actin accumulation. In addition, ${\beta}$-lapachone showed a protective role in TGF-${\beta}1$-induced ECM expression and EMT in A549 cells. Conclusion: Our results suggest that ${\beta}$-lapachone can protect against bleomycin-induced lung inflammation and fibrosis in mice and TGF-${\beta}1$-induced EMT in vitro, by elevating the $NAD^+$/NADH ratio through NQO1 activation.

Effects of Low Level Laser on the Proliferation and Gene Expression of Fibroblasts and Immune Cells (저출력레이저조사가 섬유아세포와 면역세포의 증식 및 유전자발현에 미치는 영향)

  • Ik-Jun Lim;Keum-Back Shin;Bok Choi
    • Journal of Oral Medicine and Pain
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    • v.20 no.1
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    • pp.53-65
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    • 1995
  • The growth and synthetic activities of fibroblasts are regulated by cytokines and growth factors derived from activated inflammatory cells. Stimulatory effect of low level laser (LLL) radiation on wound healing seems to be in part due to direct stimulatory action on cell proliferation and synthetic activities of fibroblasts. Also indirect stimulatory effect on the fibroblast function through inflammatory or immune cells is another possible mechanism of biostimulatory action of LLL. This study was performed to determine the growth rate of human gingival fibroblasts obtained biopsy and culture, fibroblast cell line, and immune cell line by using $[^3H]-$ thymidine incorporation test. And gene expression pattern was also analyzed by using the DNA probe such as Hsp70, IL-1$\beta$, MIP-1$\alpha$ and actin cDNA. Proliferation rate of gingival fibroblast was increased by LLL irradiation, but no more effect was added by LPS or IL-1$\beta$ pretreatment Enhanced Hsp70 gene expression was found from gingival fibroblasts and fibroblast cell line COS by LLL irradiation., which was not more increased by LPS or IL-1$\beta$ pretreatment. LLL-irradiated promyelcytic cell line HL-60 and macrophage cell line RAW264.7 showed significant stimulatory effect of proliferation rate when compared with respective control. However there were no changes in growth rate of other immune cell tested in this study, such as B cell line WR19n.l and 230, helper T cell line Jurkat and Hut78, cytolytic T cell line CTLL-r8. By LLL-irradiation Hsp70 gene expression was increased in RAW246.7 and HL-60, not in CTLL-R8. And IL-1$\beta$ and MIP-1$\alpha$ gene expression were induced only from LLL-irradiated RAW264.7. These results led us to presume that LLL radiation may affect to the immune cells, especially to macrophage, through which it might promote wound healing process.

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Gene Expression of Beta-Amyloid Precursor Protein (베타-아밀로이드 단백질 유전자 발현 연구)

  • Kim, Jong-Suk;Woo, Jong-Inn;Suh, Yoo-Hun;Kim, Ju-Han;Rhi, Bou-Yong
    • Korean Journal of Biological Psychiatry
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    • v.3 no.2
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    • pp.170-180
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    • 1996
  • Lowered immune function in the senile dementia patients may be related to the abnormal metabolism of amyloid precursor protein(APP). To investigate the passibility of an abnormal metabolism of APP in lymphocytes and the possible role of APP in the activation of lymphocytes in senile dementia patients, immunohistochemical study of rat spleen and fluorescence activated cell sorter analysis(FACS) of human lymphocytes with the specific antigen far each lymphocyte and double fluorescent marker with antibody to APP were performed. After stimulating lymphocyte with phytohemagglutinin(PHA), APP mRNA and protein were extracted and quantitfied and the influence of ${\beta}$-amyloid protein($A{\beta}$) specific antibody on lymphocyte division was investigated. In spleen, the majority of cells showing $A{\beta}$ immunoreactivity was found in the T-sell dependent zone. FACS indicated that around 90% $CD_4(+)$ T-cells and 60% of $CD_8(+)$ T-sell were immunoreactive to $A{\beta}$ specific antibody(mAb 4G8). Northern blot analysis shows that lymphocyte APP mRNA was gradually increased to reach a maximum at 3 days after activation with lectin mitogen PHA. However, the $A{\beta}$ immunoreactivity an cell surface remained constant during stimulation with PHA, indicating that the release of APP(secreted farm of APP) might be increased. A very large increase in soluble APP secretion was observed in T-lymphocyte upon activation, but only law levels in the resting stale. Immunoblot was carried out an the protein obtained from cell lysate after stimulating lymphocyte by applying PHA to the cultured lymphocyte, and the result was that $A{\beta}$ band of immature farm under 116 KDa marker decreased as the duration of culture was increased after PHA stimulation. The monoclonal $A{\beta}$ specific(4G8) and polyclonal APP antibodies did not inhibit the [$^3H$]-thymidine uptake of mitogen-treated lymphocytes significantly, suggesting that mitogenesis can not be inhibited by specific $A{\beta}$ and polyclonal APP antibody. These results suggest that APP is expressed in T-cell and might be closely associated with the function of T-cells.

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Modulatory Effect of BAY11-7082 on CD29-mediated Cell-cell Adhesion in Monocytic U937 Cells (BAY11-7082에 의한 U937 세포의 CD29-매개성 세포간 유착과정 조절 효과)

  • Kim, Byung-Hun;Cho, Jae-Youl
    • YAKHAK HOEJI
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    • v.52 no.5
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    • pp.412-417
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    • 2008
  • BAY11-7082 was initially found to be an anti-inflammatory drug with NF-${\kappa}B$ inhibitory property. In this study, we evaluated modulatory function of BAY11-7082 on U937 cell-cell adhesion induced by CD29 (${\beta}1$-integrins). BAY11-7082 strongly blocked functional activation of CD29 (${\beta}1$-integrins), as assessed by cell-cell adhesion assay. However, this compound did not block a simple activation of CD29, as assessed by cell-fibronectin adhesion assay. In particular, to understand molecular mechanism of BAY11-7082-mediated inhibition, the regulatory roles of CD29-induced actin cytoskeleton rearrangement under cell-cell adhesion and surface level of CD29 were examined using confocal and flow cytometic analysis. Interestingly, this compound strongly suppressed the molecular association of actin cytoskeleton with CD29 at cell-cell adhesion site. Moreover, BAY11-7082 also diminished surface levels of CD29 as well as its-associated adhesion molecule CD147, but not other adhesion molecules such as CD18 and CD43. Therefore, our data suggest that BAY11-7082 may be involved in regulating immune responses managed by CD29-mediated cell-cell adhesion.

A red seaweed, Polysiphonia morrowii, extract promotes β-cell regeneration in zebrasfish (Danio rerio)

  • Thilini Ranasinghe;Seon-Heui Cha
    • Fisheries and Aquatic Sciences
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    • v.27 no.1
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    • pp.17-22
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    • 2024
  • Diabetes Mellitus (DM) is a major health issue increasing worldwide. Currently, nearby half a billion people have diabetes. Two major types of DM that type 1 and type 2-DM have different etiologies but feature a crucial common pathological transition into dysfunction of pancreatic β-cells and consequently leading hyperglycemia and finally go into DM. Therefore, maintaining of β-cells such as preventing β-cells degeneration, and promoting β-cells regeneration and proliferation will be essential approaches in prevention and/or treatment of DM. There are many reports that various types of seaweed control metabolic diseases such as obesity, high blood pressure, and blood sugar control. However, no new drug candidates have been developed yet. Additionally, although seaweed has excellent blood sugar control effects, there is no evidence that it directly proliferates or regenerates beta cells. Therefore, we studied on the promotion of β-cell regeneration by a seaweed, Polysiponia morrowii extract (PME) which preserves β-cells and maintains its function. As a result, it was confirmed that PME directly promotes the proliferation of pancreatic islet β-cells with insulin secretion function in in vivo. Therefore, PME shows potential as a candidate for β-cell regeneration that may play a fundamental role in the treatment of diabetes.

Epigallocatechin Gallate Prevents Autoimmune Diabetes Induced by Multiple Low Doses of Streptozotocin in Mice

  • Song, Eun-Kyung;Hur, Hyeon;Han, Myung-Kwan
    • Archives of Pharmacal Research
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    • v.26 no.7
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    • pp.559-563
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    • 2003
  • Cytokines produced by immune cells infiltrating pancreatic islets have been incriminated as important mediators of $\beta$-cell destruction in insulin-dependent diabetes mellitus. In non insulin-dependent diabetes, cytokines are also associated with impaired $\beta$-cell function in high glucose condition. By the screening of various natural products blocking $\beta$-cell destruction, we have recently found that epigallocatechin gallate (EGCG) can prevent the in vitro destruction of RINm5F cell, an insulinoma cell line, that is induced by cytokines. In that study we suggested that EGCG could prevent cytokine-induced $\beta$-cell destruction by down-regulation of nitric oxide synthase (NOS) through inhibition of NF-kB activation. Here, to verify the in vivo antidiabetogenic effect of EGCG, we examined the possibility that EGCG could also prevent the experimental autoimmune diabetes induced by the treatment of multiple low doses of streptozotocin (MLD-STZ), which is recognized as an inducer of type I autoimmune diabetes. Administration of EGCG (100 mg/day/kg for 10 days) during the MLD-STZ induction of diabetes reduced the increase of blood glucose levels caused by MLD-STZ. Ex vivo analysis of $\beta$-islets showed that EGCG downregulates the MLD-STZ-induced expression of inducible NOS (iNOS). In addition, morphological examination showed that EGCG treatment ameliorated the decrease of islet mass induced by MLD-STZ. In combination these results suggest that EGCG could prevent the onset of MLD-STZ-induced diabetes by protecting pancreatic islets. Our results therefore revealed the possible therapeutic value of EGCG for the prevention of diabetes mellitus progression.