- Transcriptional Regulation of Insulin and CXCL10 Gene by Peroxisome Proliferator Activated Receptor gamma Coactivator-1alpha.
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Won Gu Jang, In Kyu Lee, Eun Jung Kim, Seong Yeol Ryu, Bo Wan Kim, Jung Guk Kim
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Korean Diabetes J. 2007;31(4):326-335. Published online July 1, 2007
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DOI: https://doi.org/10.4093/jkda.2007.31.4.326
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 Abstract
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- BACKGROUND
Peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC-1alpha), which act as a coactivator of nuclear receptors and several other transcription factors. This study was performed to evaluate the expressional regulation of insulin and inflammatory response genes by PGC-1alpha. METHODS: Transient transfection assays were performed to measure the promoter activity of the insulin and CXCL10 gene. The insulin gene expression levels in INS-1 cells were determined by Northern blot analysis. Differentially expressed genes by PGC-1alpha overexpression in HASMCs were confirmed using DNA microarray, real-time PCR and Northen blot analysis. RESULTS: Insulin promoter activity and mRNA levels were suppressed by GR and Ad-PGC-1alpha. Northern blot analysis of the INS-1 cells revealed that infection with Ad-PGC-1alpha markedly reduced the amount of insulin mRNA and treatment of Dex enhanced this effect in an additive manner. The PGC-1alpha-specific siRNA decreased insulin expression that was induced by Dex in the GR-expressing INS-1 cells was nearly restored by this siRNA treatment. We found that when vascular smooth muscle cells (VSMCs) overexpressed PGC-1alpha, immune or inflammatory response genes were highly expressed. For example, promoter activity and mRNA level of CXCL10 gene were increased by PGC-1alpha. CONCLUSION: PGC-1alpha overexpression inhibited insulin promoter activity in INS-1 cells and enhanced expressions of inflammatory response genes (CXCL10, CXCL11, TNFLSF10) in VSMCs.
- Microarray Analysis of Short Heterodimer Partner (SHP)-induced Changes in Gene Expression in INS-1 Cells.
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Eui Dal Jung, Ji Hyun Lee, Won Gu Jang, Jung Guk Kim, Bo Wan Kim, In Kyu Lee
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Korean Diabetes J. 2007;31(3):193-199. Published online May 1, 2007
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DOI: https://doi.org/10.4093/jkda.2007.31.3.193
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Abstract
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- BACKGROUND
Nuclear receptors are involved in the cell growth, development, differentiation, and metabolism. The orphan nuclear receptor SHP which lacks a DNA-binding domain is a negative regulator of nuclear receptor signaling pathways. In pancreas, SHP regulate transcriptional activity of HNF3 and HNF4 through binding them and BETA2 which is involved in beta cell differentiation and insulin production. Here, we examined transcriptional activity changes of genes expressed in beta cell when SHP was overexpressed. METHOD: INS-1 cells of passage number 24 - 30 were prepared. Affimetrix DNA chip was used to examine gene expression in INS-1 cell when SHP was overexpressed. INS-1 cells were infected with adenovirus-SHP to overexpress SHP. To confirm the result of DNA chip, we used real time RT-PCR. RESULT: When SHP was overexpressed by adenovirus-SHP transfection, FXR, Transforming growth factor, beta 2, fructose-1,6-bisphosphatase 2, bone morphogenetic protein 4 genes expression were increased. Contrarily, Activating transcription factor 2, Glycogen synthase kinase 3 alpha, Nur 77, fibroblast growth factor 14 genes expression were decreased. We confirmed DNA microarray analysis by real time RT-PCR. FXR, tribbles homolog 3 (Drosophila), fructose-1,6-bisphosphatase 2, CD36 genes expression were increased in real time RT-PCR. Nur 77 and cAMP response element modulator genes expression were decreased in real time RT-PCR. CONCLUSION: we identified several genes which expression are regulated by SHP in pancreas beta cell. These results help to explain how SHP act in the various metabolism of pancreas beta cell.
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