Co-Localization of Prostacyclin (PGI2)-Synthase and Caveolin-1 in Endothelial Cells Underscores New Roles of PGI2 in Angiogenesis

Abstract

In vascular cells, PGI2 synthase (PGI2s) has been localized in the endoplasmic reticulum of endothelial cells and in the nuclear and plasma membrane of smooth muscle cells (SMC). In human umbilical vein endothelial (HUVE) cells, a direct confocal microscopy approach indicates that more than 80% of the enzyme resides in cellular sites co-staining with caveolin-1 antibody. This evidence was confirmed by the demonstration that PGI2 synthase and caveolin-1 are associated to detergent-insoluble membrane domains in the same low density fractions of a sucrose gradient and the depletion of cellular cholesterol leads to the shift of PGI2s and caveolin-1 to higher density fractions of the gradient. Moreover, a double approach, based on the usage of filipin as a specific caveolae disrupting agent and antisense oligonucleotides (ODNs) targeting PGI2 synthase mRNA, suggests that the production of PGI2 in caveolae is likely to be connected to the regulation of angiogenesis, at least in vitro.KeywordsHuman Umbilical Vein Endothelial CellSucrose GradientDensity FractionCholesterol DepletionAntisense ODNsThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.