Impact of interaction of advanced glycation end product and its receptor on podocytes apoptosis / 中华肾脏病杂志

ABSTRACT

Objective To study the effects of the interaction of advanced glycation end products (AGEs) and the receptor of AGEs (RAGE) on apoptosis of mice podocytes. Methods Podocytes were exposed to soluble AGEs such as bovine serum albumin (BSA), carboxymethyl-lysin (CML)-BSA, AGE-BSA and matrix-bound AGEs (AGE-modified collagen Ⅳ ), and to different concentrations of AGE, such as 10 mg/L, 50 mg/L, 100 mg/L. Apoptosis was assessed by TUNEL staining. Fluorescence-activated cell sorting (FACS) was used for the quantification of apoptotic andnecrotic podocytes after Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling. Apoptosis was described as the ratio of apoptotic cells to the total number cells under the high-power field, siRNA was transfected into podocytes through combining Dharmacon on Targetplus SMART pool siRNA reagents and Amaxa RNAi nucleofection kit. Results The apoptosis rate was higher in podoeytes exposed to either CML-BSA or AGE-BSA than that exposed to BSA. There was a two- to three-fold increase in apoptosis when podocytes were cultured in AGE-modified collagen Ⅳ as compared with native collagen Ⅳ. The apoptotic response of podocytes to AGE-BSA exposure occurred in a dose-dependent manner. Podocyte necrosis occurred only at the highest concentration of AGE-BSA(100 mg/L). AGE-BSA failed to induce apoptosis in podocytes transfected with RAGE siRNA. RAGE-specific gene knockdown did not significantly reduce the apoptosis of podocytes cultured in AGE-modified collagen IV. Conclusions The AGE-RAGE interaction plays a major role in the apoptosis of podocytes triggered by soluble AGEs, but not by matrix-bound AGEs. Reduction of AGE burden and RAGE expression may be important therapeutic approaches to prevent the progression of kidney disease.