Diabetes & Metabolism Journal

Original Articles

Transcriptional Regulation of Insulin and CXCL10 Gene by Peroxisome Proliferator Activated Receptor gamma Coactivator-1alpha.: Won Gu Jang, In Kyu Lee, Eun Jung Kim, Seong Yeol Ryu, Bo Wan Kim, Jung Guk Kim; Korean Diabetes J. 2007;31(4):326-335. Published online July 1, 2007; DOI: https://doi.org/10.4093/jkda.2007.31.4.326

2,279 View
22 Download

Abstract PDF: 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.

Effect of Glucose Concentrations on the Cell Proliferation and Expression of L-type Calcium Channel mRNA in Cultured Rat Aortic Vascular Smooth Muscle Cells.: Young Jung Cho, Hyung Joon Yoo, Hong Woo Nam, Ji Young Suh, In Kyung Jeong, Sung Hee Ihm, Hyeon Kyu Kim, Cheol Young Park, Jae Myung Yoo, Doo Man Kim, Moon Gi Choi, Sung Woo Park; Korean Diabetes J. 2003;27(3):253-259. Published online June 1, 2003

1,266 View
25 Download

Abstract PDF: BACKGROUND
Vascular smooth muscle cell (VSMC) proliferation is one of the major pathogenic mechanisms for atherosclerosis. It is known that L-type calcium channels play a role in VSMC proliferation in diabetic rats. However, there have been no studies that show an association between the L-type calcium channels and the VSMC proliferation due to various glucose concentrations in the culture media. Therefore, the association between the voltage-dependent L-type calcium channels of the VSMCs, and the growth of vascular smooth muscle cells, was examined. METHODS: Rat aortic VSMCs were isolated from the aorta of Sprague-Dawley and OLETF rats, using an enzymic method. The VSMCs were cultured in various concentrations of glucose (5.5, 11.0, 16.6, 25, 30 and 40 mM). The VSMCs (1x10(4) cells in 24-well plates) were incubated in the presence of Bay K 8644 (10(-6)M), both with and without verapamil (10(-6)M), for 48 hours. The proliferation was then assessed by the MTT (methylthiazole tetrazolium) assay, and the expression of L-type calcium channel mRNA by RT-PCR. RESULTS: The vascular smooth muscle cell proliferation was significantly increased, in a dose-dependent manner, with glucose concentrations below 25 mM in both in a dose-dependent manner, with glucose concentrations below 25 mM in both kinds of rat. However, the increase in the VSMC proliferation of the OLETF rat was significantly higher than in the Sprague-Dawley rat. After the Bay K 8644 treatment, with the same glucose concentration, the VSMC proliferation and the expression of L-type calcium channel mRNA were significantly increased in both kinds of rat. After treatment with verapamil, the increased VSMC proliferation and expression of L-type calcium channel mRNA, due to the Bay K 8644, were suppressed to control levels in both kinds of rat. CONCLUSION: The results suggest that below certain concentrations of glucose, 25 mM, the L-type calcium channels may play a role in the VSMC proliferation of OLETF and Sprague-Dawley rats. The growth of the VSMCs in OLETF rats, due to various glucose concentrations (< 25 mM), was significantly higher than in the Sprague-Dawley rats.

Effect of Transforming Growth Factor-Induced Gene Product, beta ig-h3 on Proliferation, Migration, and Adhesion of Aortic Smooth Muscle Cells Cultured in High Glucose.: Sung Woo Ha, Gui Hwa Jung, He Jin Yeo, Jong Sup Bae, Soon Hee Lee, Jung Guk Kim, Rang Woon Park, In San Kim, Bo Wan Kim; Korean Diabetes J. 2002;26(4):286-295. Published online August 1, 2002

1,007 View
17 Download

Abstract PDF: BACKGROUND
Diabetes mellitus is associated with a substantial increase in the prevalence of atherosclerotic disease. There are many factors which are involved in development of these processes. Transforming growth factor (TGF-beta) is known to be an important factor in the pathogenesis of diabetic vascular complications. TGF-beta-induced gene-h3 (beta ig-h3) is an adhesive molecule whose expression is induced by TGF-beta. Considering that TGF-beta plays an important role in diabetic complications and that beta ig-h3 is induced by TGF-beta, we hypothesized that beta ig-h3 may also play a role in the development of diabetic angiopathy. Then, we examined the effects of beta ig-h3 on biologic function of vascular smooth muscle cells (VSMCs) and potential roles of beta ig-h3 in the pathognesis of diabetic angiopathy. METHODS: VSMCs were isolated from rat thoracic aorta. We conditioned cells with different concentration of TGF-beta or glucose. We measured TGF-beta and beta ig-h3 protein in cell supernatant by ELISA. We also examined whether TGF-beta involves in high glucose-induced beta ig-h3 expression. Finally, we did proliferation, migration, and adhesion assay to investigate biologic function of beta ig-h3 in VSMCs. RESULTS: Our results demonstrated that TGF-beta induced beta ig-h3 expression in VSMCs in dose dependent manners. High glucose induced TGF expression as well as beta ig-h3 protein. Finally, beta ig-h3 was found to support the proliferation, migration, and adhesion of rat VSMCs. CONCLUSION: These results suggest that high glucose-and TGF-beta-induced beta ig-h3 may play an important role in diabetic angiopathy by regulating proliferation, migration, and adhesion of VSMCs.

Effect of Advanced Glycation End Products on Rat Aortic Vascular Smooth Muscle Cells.: Jin Young Song, Sung Hee Ihm, Ji Young Suh, Young Joong Cho, Hyung Joon Yoo, Sung Woo Park, Ja Hei Ihm; Korean Diabetes J. 2002;26(2):91-99. Published online April 1, 2002

1,242 View
20 Download

Abstract PDF: BACKGROUND
Diabetes mellitus is an epidemiologically proven risk factor for atherosclerosis. Advanced glycation end products (AGE) have been implicated in the pathogenesis of many diabetic vascular complications. AGE not only change the physicochemical properties of proteins, but also induce a wide range of cell-mediated responses. However, biological effects of AGE on the vascular smooth muscle cells (VSMCs) have not been fully explained despite of presence of an AGE-receptor on the VSMCs. METHODS: In order to test whether AGE promotes atherosclerosis by stimulation of the growth promoting signal transduction pathways in the VSMCs, the proliferation of rat aortic VSMCs cultured in the presence of AGE-BSA with/without anti-AGE antibodies, the MAP kinase inhibitor and antioxidants was measured. The VSMCs (1 x 104 cells in 24-well plates) isolated from the aorta of Sprague-Dawley rats were incubated for 48 hours and the proliferation was assessed by a MTT assay. RESULTS: AGE-BSA increased the proliferation of rat aortic VSMCs by 1.5~1.6 fold at the g/mL level. The stimulatory effect of AGE-BSA (5 microgram/mL) was blocked by the anti-AGE antibodies (100 microgram/mL). PD98059 at 50 M inhibited the AGE - BSA - induced VSMC proliferation, suggesting that MAP kinase activation might be responsible for the proliferative response of the VSMCs to AGE. AGE - BSA - induced VSMC proliferation was also attenuated by N-acetylcysteine (1 micro M) and butylated hydroxyanisole (10 micro M), implying that increased intracellular oxidative stress might be also involved in the proliferative response to AGE. CONCLUSION: These results suggest AGE play a role in diabetic atherosclerosis by stimulating of the growth promoting signal transduction pathways in the VSMCs.

First
Prev
Page of 1
Next
Last

Search