SrcE97A Mediates convergent regulation of arterial/venous thrombosis and immune homeostasis via β3-Src dissociation.

BACKGROUND

Integrin β3 orchestrates thrombotic and inflammatory processes through bidirectional signaling, with Src acting as a key downstream effector.

OBJECTIVES

To dissect this axis, we generated SrcE97A mice that selectively disrupt the interaction between Src and integrin β3, impairing outside-in signaling while preserving inside-out signaling through integrin β3.

METHODS

Platelet function was assessed through clot retraction, irreversible aggregation, thrombus stabilization under flow, and soluble fibrinogen binding. Thrombosis models included FeCl3-induced carotid artery and laser-induced cremaster arteriole injury for arterial thrombosis, and the inferior vena cava ligation for deep vein thrombosis. Hemostasis was evaluated in parallel. The impact on cerebral infarction was measured in vivo. In addition, the biological functions of αvβ3 outside-in signaling were also analyzed.

RESULTS

The SrcE97A mutation impaired outside-in signaling while preserving inside-out signaling in platelets. This suppressed αIIbβ3-mediated clot retraction, secondary aggregation, and thrombus stabilization under flow. SrcE97A mice showed reduced arterial and venous thrombosis without hemostatic compromise. These antithrombotic effects were reinforced by protection against cerebral infarction in vivo. Furthermore, the E97A mutation influenced immunologic regulation. Specifically, it promoted pulmonary inflammation by skewing T helper (Th) cell differentiation toward Th1, via disruption of the αvβ3-Src-STAT4/6 signaling axis.

CONCLUSIONS

These findings establish integrin β3 as a dual regulator of thrombosis and immune homeostasis. Selective disruption of outside-in signaling attenuates pathologic thrombosis without compromising hemostasis and reshapes Th1/Th2 balance. Targeting the Src E97 interface may offer strategies to inhibit pathologic thrombosis and modulate inflammation.