Advanced glycation end-products activate extracellular signal-regulated kinase via the oxidative stress-EGF receptor pathway in renal fibroblasts

Advanced glycation end‐products (AGEs), epidermal growth factor receptor (EGFR), reactive oxygen species (ROS), and extracellular signal‐regulated kinases (ERK) are implicated in diabetic nephropathy (DN). Therefore, we asked if AGEs‐induced ERK protein phosphorylation and mitogenesis are dependent on the receptor for AGEs (RAGE)–ROS–EGFR pathway in normal rat kidney interstitial fibroblast (NRK‐49F) cells. We found that AGEs (100 µg/ml) activated EGFR and ERK1/2, which was attenuated by RAGE short‐hairpin RNA (shRNA). AGEs also increased RAGE protein and intracellular ROS levels while RAGE shRNA and N‐acetylcysteine (NAC) attenuated AGEs‐induced intracellular ROS. Hydrogen peroxide (5–25 µM) increased RAGE protein level while activating both EGFR and ERK1/2. Low‐dose hydrogen peroxide (5 µM) increased whereas high‐dose hydrogen peroxide (100 µM) decreased mitogenesis at 3 days. AGEs‐activated EGFR and ERK1/2 were attenuated by an anti‐oxidant (NAC) and an EGFR inhibitor (Iressa). Moreover, AGEs‐induced mitogenesis was attenuated by RAGE shRNA, NAC, Iressa, and an ERK1/2 inhibitor (PD98059). In conclusion, it was found that AGEs‐induced mitogenesis is dependent on the RAGE–ROS–EGFR–ERK1/2 pathway whereas AGEs‐activated ERK1/2 is dependent on the RAGE–ROS–EGFR pathway in NRK‐49F cells. J. Cell. Biochem. 109: 38–48, 2010. © 2009 Wiley‐Liss, Inc.