PI3Kγ signaling controls trafficking of CD8⁺ T cells between lymphoid and non-lymphoid organs and drives hypertension in a murine model.

Abstract

Activated immune cells infiltrate the vasculature during the pathophysiology of hypertension by establishing a vascular-immune interface that contributes to blood pressure dysregulation and organ failure. Many observations indicate a key role of CD8⁺ T cells in hypertension but mechanisms regulating their activation and interplay with the cardiovascular system are still unknown. In murine model, here we show that a specific member of the phosphoinositide-3-kinases (PI3K) family of lipid kinases, PI3Kγ, is a key intracellular signaling of CD8⁺ T cells activation and RANTES/CCL5 secretion in hypertension: CCL5-CCR5 signaling is crucial for the establishment of the vascular-immune interface in peripheral organs, lastly contributing to CD8⁺ tissue infiltration, organ dysfunction and blood pressure elevation. Our studies identify PI3Kγ as a booster of effector CD8⁺ T cell function, even in the absence of external stimuli. Lastly, an enhanced PI3Kγ signaling mediates the bystander activation of CD8⁺ T cells and proves effective in transferring the hypertensive phenotype between mice.