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

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Advanced glycation end products (AGEs) contribute to endothelial dysfunction.
• Protein kinase B (AKT) activation is known to mitigate AGEs' harmful effects, but the underlying mechanisms are unclear.
• Intercellular adhesion molecule-1 (ICAM-1) expression is upregulated by AGEs in endothelial cells, promoting inflammation.

Purpose of the Study:

• To elucidate the molecular mechanisms by which AKT signaling suppresses AGEs-induced ICAM-1 expression in human aortic endothelial cells (HAECs).
• To investigate the roles of ADAM10, RAGE, and Rab14 in AKT-mediated protection against AGEs.

Main Methods:

• Cell culture of HAECs treated with AGE-bovine serum albumin (AGE-BSA) and AKT activator SC79.
• Pharmacological inhibition and siRNA-mediated knockdown of AKT isoforms, ADAM10, and Rab14.
• Analysis of ICAM-1 expression, ADAM10 cell surface translocation, and RAGE ectodomain shedding.
• Co-immunoprecipitation assays to assess protein interactions.

Main Results:

• SC79 treatment activated AKT1, AKT2, and AKT3, leading to ADAM10 translocation to the cell surface and RAGE ectodomain shedding.
• Inhibition of ADAM10 or AKT prevented SC79-induced RAGE shedding and ICAM-1 suppression.
• Rab14 was found to co-immunoprecipitate with ADAM10 and was essential for SC79-induced ADAM10 cell surface translocation and RAGE shedding.
• Rab14 knockdown abolished the protective effects of SC79 against AGE-BSA-induced ICAM-1 expression.

Conclusions:

• AKT activation suppresses AGE-BSA-induced ICAM-1 expression in HAECs.
• This protective effect is mediated by Rab14-dependent translocation of ADAM10 to the cell surface, which induces RAGE ectodomain shedding.
• The findings reveal a novel signaling pathway involving AKT, Rab14, ADAM10, and RAGE in endothelial cell protection against AGEs.