OBJECTIVE: To investigate whether the morphological and functional changes typical of cell immobilization induced by free cholesterol (FC) accumulation in macrophages is related to the activity of the ATP-binding cassette transporter (ABCA1). METHODS AND RESULTS: FC loading induced actin rearrangement with ruffling and cell spreading in macrophages that normally express ABCA1, but to a significant lesser extent in ABCA1-KO mouse peritoneal macrophages (MPMs) and in normal cells upon pharmacological inhibition of ABCA1 with probucol. In ABCA1-KO MPMs and in probucol-treated J774 cell migration was inhibited to a lower extent by FC as compared to control cells. Similar results were found in stably ABCA1 knocked down J774 (ABCA1-KD-J774) obtained by RNA interference. FC accessible to cholesterol oxidase, a measure of plasma membrane FC content, was significantly higher in FC-loaded WT MPMs and control J774 than in FC-loaded ABCA1-KO MPMs, ABCA1-KD-J774 or probucol-treated J774. In parallel plasma membrane total phospholids and sphingomyelin increased after cholesterol loading in control J774 but not in ABCA1-KD-J774. In addition, apoA-I, that removes FC from ABCA1 specific pool, partially restored chemotactic response in FC-loaded control J774. No effect was observed with HDL(2) that does not interact with ABCA1. Finally, FC-induced Rac activation was more efficient in control J774 than in ABCA1-KD-J774. and was prevented by probucol and apoA-I in control J774. CONCLUSION: In macrophages ABCA1 activity mediates FC ability to alter plasma membrane organization, to inhibit cell migration, and to activate a Rac-mediated signaling pathway.
Free cholesterol alters macrophage morphology and mobility by an ABCA1 dependent mechanism / M.P. Adorni, E. Favari, N. Ronda, A. Granata, S. Bellosta, L. Arnaboldi, A. Corsini, R. Gatti, F. Bernini. - In: ATHEROSCLEROSIS. - ISSN 0021-9150. - 215:1(2011 Mar), pp. 70-76.
|Titolo:||Free cholesterol alters macrophage morphology and mobility by an ABCA1 dependent mechanism|
|Parole Chiave:||Animals ; Cell Migration Assays ; Humans ; Mice ; Cholesterol ; Mice, Knockout ; Gene Knockdown Techniques ; Macrophages, Peritoneal ; Cell Membrane ; Mice, Inbred C57BL ; ATP-Binding Cassette Transporters ; rac GTP-Binding Proteins ; Signal Transduction|
|Settore Scientifico Disciplinare:||Settore BIO/14 - Farmacologia|
Settore BIO/11 - Biologia Molecolare
|Data di pubblicazione:||mar-2011|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.atherosclerosis.2010.12.004|
|Appare nelle tipologie:||01 - Articolo su periodico|
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