AKT activation triggers Rab14-mediated ADAM10 translocation to the cell surface in human aortic endothelial cells

Abstract

AKT (protein kinase B) activation reduces the harmful effects of advanced glycation end products (AGEs); however, the protective mechanisms remain unknown. In cultured human aortic endothelial cells (HAECs), we investigated how AKT signaling suppresses AGEs-induced intercellular adhesion molecule-1 (ICAM-1) expression. AGEs of bovine serum albumin (AGE-BSA) increased ICAM-1 expression, but this effect was abolished by pretreatment with the AKT activator SC79. SC79 activated AKT1, AKT2, and AKT3, translocated a disintegrin and metalloprotease 10 (ADAM10) to the cell surface, and induced ectodomain shedding of the receptor for AGEs (RAGE). In contrast, GI 254023X-mediated ADAM10 inhibition and siRNA-mediated ADAM10 knockdown both prevented SC79-induced RAGE ectodomain shedding. On the other hand, MK-2206, a pan-AKT inhibitor, and siRNA-mediated knockdown of AKT1, AKT2, or AKT3 prevented SC79-induced ADAM10 cell surface translocation and RAGE ectodomain shedding. Notably, Rab14 was co-immunoprecipitated with ADAM10. Following SC79 treatment, Rab14 moved to the cell surface, whereas siRNA-mediated Rab14 knockdown prevented SC79 from promoting ADAM10 cell surface translocation and RAGE ectodomain shedding and abolished SC79’s ability to inhibit AGE-BSA-induced ICAM-1 expression. In conclusion, upon activation of all three isoforms, AKT suppresses AGE-BSA-induced ICAM-1 expression by inducing ADAM10-mediated RAGE ectodomain shedding. This occurs because AKT signaling boosts Rab14-dependent ADAM10 cell surface translocation.