Gas6‐induced tissue factor expression in endothelial cells is mediated through caveolin‐1–enriched microdomains

Summary
BackgroundGas6 has been shown to interact with Axl in endothelial cells and to induce several signaling pathways involved in cell survival and proliferation. However, the interaction of Gas6/Axl with lipid raft/caveolin‐1 in endothelial cells and its role in thrombosis are unknown.
ObjectivesWe tested whether Axl and/or caveolin‐1 is involved in Gas6–induced Akt, ERK1/2, and c‐Src activation leading to altered tissue factor expression in endothelial cells.
MethodsGas6‐treated endothelial cells were transfected with small interfering RNA (siRNA) for Axl, caveolin‐1, c‐Src, and Akt or treated with pharmacological inhibitors of c‐Src and ERK1/2. Sucrose gradient centrifugation and confocal microscopy were used to study lipid raft/caveolin‐1–enriched fractions. Akt, ERK1/2, p38, and c‐Src activation was analyzed by Western blot analysis. Tissue factor expression was assessed by real‐time quantitative polymerase chain reaction and immunofluorescence.
Results and conclusionGas6 induced Axl and c‐Src localization into lipid raft/caveolin‐1–enriched fractions. Gas6 increased the phosphorylation of Akt, ERK1/2, and c‐Src but not p38. Using siRNA, we demonstrated that Axl is required for Akt, ERK1/2, and c‐Src activation after Gas6 stimulation. siRNA for caveolin‐1 blocked Gas6‐induced phosphorylation of Akt, ERK1/2, and c‐Src. c‐Src downregulation inhibited Gas6‐induced Akt but not ERK1/2 phosphorylation. Finally, Gas6 increased tiss...

Source: Journal of Thrombosis and Haemostasis - March 5, 2014 Category: Hematology Authors: S. Laurance, M. N. Aghourian, Z. Jiva Lila, C. A. Lemarié, M. D. Blostein Tags: Original Article Source Type: research