Advanced glycation endproducts increase EPC apoptosis and decrease nitric oxide release via MAPK pathways

Abstract

Objective Previous studies have shown that advanced glycation endproducts (AGE) can induce endothelial progenitor cells (EPC) apoptosis, which contributes to the pathogenesis of diabetes mellitus. Nitric oxide (NO) signaling is closely associated with apoptosis. We therefore investigated the effects of AGE on human EPC apoptosis, NO release and related signal transduction pathways. Methods EPC isolated from healthy human subjects were cultured with various concentrations of AGE (0, 2, 20 and 200 mg/L) for 0, 24, 48 and 72 h in the presence or absence of various MAPK (ERK/P38/JNK) inhibitors, respectively. EPC apoptosis (detected by flow cytometric analyses) and NO concentration in culture supernatant were determined. The mRNA levels of eNOS, COX-2, Bcl-2 and Bax were assessed by RT-PCR and the protein expressions of NF-κB and Caspase-3 assessed by Western blot. Results Increased EPC apoptosis and reduced NO release were induced by 200 mg/L AGE, accompanied by a downregulation of eNOS and Bcl-2 expressions as well as an elevation in COX-2, Bax, NF-κB and Caspase-3 expressions in a time-dependent manner (all P < 0.05). These changes were significantly attenuated by pretreatment with various MAPK (ERK/P38/JNK) inhibitors ( P < 0.05). Conclusions AGE can promote EPC apoptosis and decrease NO release via MAPK pathways.