Connective Tissue Growth Factor Is A Mediator In The Expression Of Fibronectin In Cultured Human Mesangial Cells Induced By Advanced Glycation End Products

Aim: To investigate the effects of advanced glycation end products (AGEs) on proliferation and expression of connective tissue growth factor (CTGF) and fibronectin (FN) in cultured human mesangial cells (HMC); and to determine whether CTGF is an autocrine mediator in the expression of fibronectin (FN) induced by AGEs.Methods: Human mesangial cells were cultured in Dulbecco modified Eagle medium (DMEM) and were incubated with AGEs modified bovine serum albumin (AGE-BSA) and various agents. The supernatants and cells were collected for various assay. Cellular proliferation activity were measured by method of methyl thiazolyl tetrazolium (MTT) and mRNA of CTGF and FN were measured by reverse transcription polymerase chain reaction (RT-PCR). Spectrophotometry, immunocytochemistry were used to detect the activities of SOD and CAT, the level of MDA. FN protein levels were identified by FN enzynze linked immunosorborbent assay (ELISA).Results: It was found that proliferation of mesangial cells and expression of CTGF mRNA and FN mRNA were significantly enhanced by incubation of AGEs in a time- and dose-related manner, which can be partly inhibited by aminoguanidine (P<0.05). The levels of MDA, SOD and CAT in supernatants were increased in culrured cells exposed to AGEs in a time-dependent way. Increased level of MDA and decreased activities of SOD and CAT were induced by AGEs treatment (P<0.05). In the same system, recombinant human CTGF added into cultured cell enhanced cellular expression of FN mRNA and FN protein. Neutralizing antibody of CTGF was shown to significantly, but not fully attenuated the expression of FN mRNA and FN protein induced by AGEs (P<0.05).Conclusions: The proliferation and expression of CTGF mRNA and FN mRNA in human mesangial cells were upregulated by AGEs. Connective tissue growth factor is a mediator in the expression of fibronectin in cultured human mesangial cells induced by AGEs, which might have potential implications for the pathgenic mechanism of diabetic nephropathy and therapeutic target.