Interferon regulatory factor-1 as a positive regulator for high glucose-induced proliferation of vascular smooth muscle cells

High glucose-induced proliferation of vascular smooth muscle cells (VSMCs) plays an important role in the development of diabetic vascular diseases. However, molecular mediators responding for the proliferation of VSMCs remain to be determined. In this study, VSMCs were isolated from the rat thoracic aorta, and two cell models with Irf-1 knockdown and overexpression were established by transfecting cells with pGCsi-FU-Irf-1 and pGC-FU-Irf-1, respectively. Subsequently, high glucose was added to cells to induce proliferation. Proliferation assays were performed to see whether Irf-1 was involved in high glucose-induced proliferation of VSMCs. In addition, the expression of Irf-1 was detected in VSMCs stimulated with high glucose and the thoracic aorta of diabetic rats to confirm the relationship between Irf-1 expression and the proliferation of hyperglycemia-dependent VSMCs. The results showed that Irf-1 expression was significantly higher in the thoracic aorta of diabetic rats and VSMCs stimulated with high glucose than that in nondiabetic rats and untreated cells. Overexpression of Irf-1 accelerated the proliferation of VSMCs, and down-regulation of Irf-1 expression significantly depressed the proliferative ability of VSMCs under high-glucose conditions, indicating that Irf-1 was a positive regulator for high glucose-induced proliferation of VSMCs. It could be presumed that Irf-1 is associated with the accelerated proliferation of VSMCs in diabetic vascular diseases and may prove to be a potential target gene for disease treatment.     

FK506增强雷公藤内酯醇对滑膜成纤维细胞COX—2和iNOS表达的抑制作用

研究了FK5 0 6对雷公藤内酯醇抑制类风湿关节炎滑膜成纤维细胞 (RASF)增殖和表达环氧化酶 2 (COX 2 )、诱导型一氧化氮合酶 (iNOS)及合成前列腺素E2 (PGE2 )、一氧化氮 (NO)的影响 ,探讨了FK5 0 6联合雷公藤抗类风湿作用的机制。分离培养人类风湿关节炎滑膜成纤维细胞 ,用不同浓度的FK5 0 6处理后 ,加或不加雷公藤内酯醇 (TP)和TNFα ,分别用 [3H] TdR法、竞争ELISA和硝酸酶还原法、半定量逆转录 聚合酶链反应 (RT PCR)法、细胞酶免疫法及Western印迹法检测滑膜细胞的增殖活性、细胞培养上清液中PGE2和NO的水平、滑膜细胞COX 2和iNOSmRNA表达水平及蛋白质表达水平。同时提取各组细胞蛋白质 ,测定其核转录因子NF κB活性。结果表明 ,FK5 0 6( 10～ 10 0 0nmol/L)及低浓度的TP( 10 μg/L)单独对TNFα活化的RASF表达COX 2、iNOS及合成PGE2、NO均无明显的抑制作用 ;FK5 0 6与低浓度的TP联合作用后 ,对活化的RASF具有不同程度的抑制作用 ,并与联合的FK5 0 6浓度 ( 10～ 10 0 0nmol/L)呈明显正相关性 ,且两者联合对TNFα激活的RASF核转录因子NF κB活性有明显的抑制作用。实验未观察到FK5 0 6对TP抑制滑膜细胞增殖的影响。以上结果说明 ,FK5 0 6可显著增强TP对滑膜细胞COX 2和iNOS的表达及其产物PGE2和NO合成