Platelet Activating Factor-Induced Ceramide Micro-Domains Drive Endothelial NOS Activation and Contribute to Barrier DysfunctionReportar como inadecuado




Platelet Activating Factor-Induced Ceramide Micro-Domains Drive Endothelial NOS Activation and Contribute to Barrier Dysfunction - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

The spatial and functional relationship between platelet activating factor-receptor PAF-R and nitric oxide synthase eNOS in the lateral plane of the endothelial plasma membrane is poorly characterized. In this study, we used intact mouse pulmonary endothelial cells ECs as well as endothelial plasma membrane patches and subcellular fractions to define a new microdomain of plasmalemma proper where the two proteins colocalize and to demonstrate how PAF-mediated nitric oxide NO production fine-tunes ECs function as gatekeepers of vascular permeability. Using fluorescence microscopy and immunogold labeling electron microscopy EM on membrane patches we demonstrate that PAF-R is organized as clusters and colocalizes with a subcellular pool of eNOS, outside recognizable vesicular profiles. Moreover, PAF-induced acid sphingomyelinase activation generates a ceramide-based microdomain on the external leaflet of plasma membrane, inside of which a signalosome containing eNOS shapes PAF-stimulated NO production. Real-time measurements of NO after PAF-R ligation indicated a rapid 5 to 15 min increase in NO production followed by a > 45 min period of reduction to basal levels. Moreover, at the level of this new microdomain, PAF induces a dynamic phosphorylation-dephosphorylation of Ser, Thr and Tyr residues of eNOS that correlates with NO production. Altogether, our findings establish the existence of a functional partnership PAF-R-eNOS on EC plasma membrane, at the level of PAF-induced ceramide plasma membrane microdomains, outside recognized vesicular profiles.



Autor: Sanda Predescu, Ivana Knezevic, Cristina Bardita, Radu Florin Neamu, Viktor Brovcovych, Dan Predescu

Fuente: http://plos.srce.hr/



DESCARGAR PDF




Documentos relacionados