Apolipoprotein E Receptor 2 Mediates Activated Protein C-Induced Endothelial Akt Activation and Endothelial Barrier Stabilization.

Autor:	Sinha RK; From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA., Yang XV; From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA., Fernández JA; From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA., Xu X; From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA., Mosnier LO; From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA., Griffin JH; From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA. jgriffin@scripps.edu.
Jazyk:	angličtina
Zdroj:	Arteriosclerosis, thrombosis, and vascular biology [Arterioscler Thromb Vasc Biol] 2016 Mar; Vol. 36 (3), pp. 518-24. Date of Electronic Publication: 2016 Jan 21.
DOI:	10.1161/ATVBAHA.115.306795
Abstrakt:	Objective: Activated protein C (APC), a plasma serine protease, initiates cell signaling that protects endothelial cells from apoptosis and endothelial barrier disruption. Apolipoprotein E receptor 2 (ApoER2; LRP8) is a receptor known for mediating signaling initiated by reelin in neurons. ApoER2 contributes to APC-initiated signaling in monocytic U937 cells. The objective was to determine whether ApoER2 is required for APC's beneficial signaling in the endothelial cell surrogate EA.hy926 line. Approach and Results: We used small interfering RNA and inhibitors to probe requirements for specific receptors for APC's antiapoptotic activity and for phosphorylation of disabled-1 by Src family kinases and of Akt. When small interfering RNA for ApoER2 or endothelial cell protein C receptor or protease activated receptor 1 was used, APC's antiapoptotic activity was ablated, indicating that each of these receptors was required. In EA.hy926 cells, APC induced a 2- to 3-fold increased phosphorylation of Ser473-Akt and Tyr232-disabled-1, a phosphorylation known to trigger disabled-1-mediated signaling in other cell types. Ser473-Akt phosphorylation was inhibited by ApoER2 small interfering RNA or by inhibitors of Src (PP2), phosphatidylinositol-3 kinase (LY303511), and protease activated receptor 1 (SCH79797). ApoER2 small interfering RNA blocked the ability of APC to prevent thrombin-induced endothelial barrier disruption in TransEndothelial Resistance assays. Binding studies using purified APC and purified immobilized wild-type and mutated ApoER2 ectodomains suggested that APC binding involves Lys49, Asp50, and Trp64 on the surface of the N-terminal LA1 domain of ApoER2. Conclusions: ApoER2 contributes cooperatively with endothelial cell protein C receptor and protease activated receptor 1 to APC-initiated endothelial antiapoptotic and barrier protective signaling. (© 2016 American Heart Association, Inc.)
Databáze:	MEDLINE
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