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. J. Cell. Biochem. 113: 2671–2678, 2012. © 2012 Wiley Periodicals, Inc.