Mechanism Research Of Resistin Regulates The Transportation Of Glucose And Insulin In Human Endothelial Cells

It is a key step for glucose and insulin in blood to enter into tissue for maintaining the glucose homeostasis in human body, if glucose and insulin are blocked in the blood vessel, hampered to get to targeted tissue and organ, resulting in hyperglycemia, insulin resistance and Type II Diabetes Mellitus. The vascular wall is constructed by single-layer and multi-layers vascular endothelial cells, the glucose and insulin transportation ability of vascular endothelial cell is crucial for whether glucose and insulin can get into tissue and organ. Resistin has been considered to be correlated with inflammation, insulin resistance and Type II Diabetes Mellitus. The permeability of vascular endothelial cell for glucose and insulin was decreased after treated by resistin, this reveals resistin can lead to insulin resistance through a new signal pathway, however the underlying mechanism remains unclear.To explore the underlying mechanism, we constructed vascular wall model in vitro by using EA.hy 926 cells. The expression level of two factors: GLUT1 and INSR, which are essential to the transportation of glucose and insulin was detected, and we constructed GLUT1 promoter vector, the transcription activity of GLUT1 promoter vector was measured by dual luciferase reporter system, we probed the molecular mechanism of GLUT1 regulated by resistin. The results are as follow:1. After stimulating EA.hy 926 with resistin, the extracted RNA and protein were detected by RT-PCR and Western Blot respectively, we found the m RNA level and protein level of GLUT1 and INSR were down-regulated by resistin.2. Immunofluorescence experiment indicated the fluorescence of GLUT1 protein in EA.hy 926 decreased after stimulated by resistin. Overexpression of GLUT1 in EA.hy 926 can reverse the decreased permeability of glucose caused by resistin.3. To further explore the down-regulation mechanism resistin plays on GLUT1, we constructed GLUT1 promoter vector. Through the test of Dual-Luciferase Reporter Assay System, we found PPARγ could specifically bind to GLUT1 promoter to up-regulate the transcription level of promotor which showed resistin regulated the expression level of GLUT1 through PPARγ.Our research reveals, through a pathway: Resistin—PPARγ—GLUT1—Glucose Transportion, resistin can regulate the glucose transportation in vascular endothelial cells, then further affect the entry of glucose into vascular endothelial cells, decrease glucose oxidation utilization of the tissue.