Beta-adaptin: key molecule for microglial scavenger receptor function under oxidative stress.

Scavenger receptors internalize chemically modified low density lipoprotein particles (ac-LDL) and other ligands through the process of receptor-mediated endocytosis. During this investigation using amyloid-beta as a natural ligand for the SR, we studied under a ligand-induced oxidative stress condition, changes in protein expression of several adaptor proteins important in the organization of the endocytic machinery in microglia and macrophages. Differential expression experiments of beta-adaptin, alpha-adaptin, SR-AI, and SR-BI in RAW (macrophages) and EOC (microglia) cells were performed according to dosage and exposure time to amyloid-beta. Our results show that according to dosage, amyloid-beta produces an oxidative stress state that importantly affects the availability of beta-adaptin. Under these conditions, RT-PCR assays show that beta-adaptin mRNA is normally synthesized, reason why protein translation or protein structure of beta-adaptin might be altered. These observations might have impact in the understanding of the mechanisms microglia employ to process amyloid-beta in the brain.