Endothelial p110γPI3K Mediates Endothelial Regeneration and Vascular Repair Following Inflammatory Vascular Injury
Background—The integrity of endothelial monolayer is a sine qua non for vascular homeostasis and maintenance of tissue fluid balance. However, little is known about the signaling pathways regulating regeneration of the endothelial barrier following inflammatory vascular injury.
Methods and Results—Employing genetic and pharmacological approaches, we demonstrated that endothelial regeneration selectively requires activation of p110γPI3K signaling, which thereby mediates the expression of the endothelial reparative transcription factor FoxM1. We observed that FoxM1 induction in the pulmonary vasculature was inhibited in mice treated with p110γ-selective inhibitor and in Pik3cg-/- mice following LPS challenge. Pik3cg-/- mice exhibited persistent lung inflammation induced by sepsis and sustained increase in vascular permeability. Restoration of expression of either p110γ or FoxM1 in pulmonary endothelial cells of Pik3cg-/- mice restored endothelial regeneration and normalized the defective vascular repair program. We also observed diminished expression of p110γ in pulmonary vascular endothelial cells of ARDS patients, suggesting that impaired p110γ-FoxM1 vascular repair signaling pathway is a critical factor in persistent leaky lung microvessels and edema formation in the disease.
Conclusions—We identify p110γ as the critical mediator of endothelial regeneration and vascular repair following sepsis-induced inflammatory injury. Thus, activation of p110γ-FoxM1 endothelial regeneration may represent a novel strategy for the treatment of inflammatory vascular diseases.
- acute lung injury
- acute respiratory distress syndrome
- endothelial regeneration
- endovascular repair
- vascular disease
- vascular endothelium
- Received December 17, 2015.
- Revision received January 25, 2016.
- Accepted January 29, 2016.