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

Area of Science:

• Endothelial cell biology
• Molecular signaling pathways
• Thrombosis research

Background:

• Gas6 interacts with Axl in endothelial cells, activating survival and proliferation pathways.
• The role of Gas6/Axl in lipid rafts and caveolin-1, and its link to thrombosis, is not well understood.

Purpose of the Study:

• To investigate the involvement of Axl and caveolin-1 in Gas6-induced signaling.
• To determine the role of these interactions in tissue factor expression and endothelial cell prothrombotic activity.

Main Methods:

• Endothelial cells were treated with Gas6 and subjected to siRNA for Axl, caveolin-1, c-Src, and Akt.
• Pharmacological inhibitors of c-Src and ERK1/2 were used.
• Lipid raft fractions were analyzed using sucrose gradient centrifugation and confocal microscopy.
• Protein activation and tissue factor expression were assessed via Western blot and qPCR/immunofluorescence.

Main Results:

• Gas6 induced Axl and c-Src localization into lipid raft/caveolin-1 fractions.
• Gas6 increased phosphorylation of Akt, ERK1/2, and c-Src, dependent on Axl and caveolin-1.
• c-Src inhibition affected Akt but not ERK1/2 phosphorylation.
• Gas6 upregulated tissue factor mRNA and protein expression.

Conclusions:

• The Gas6/Axl/caveolin-1/c-Src/Akt signaling axis is crucial for Gas6-mediated tissue factor expression in endothelial cells.
• This pathway provides mechanistic insight into the prothrombotic effects of Gas6 in the vasculature.