Activation of endothelial GABAA receptor α1 subunit protects against barrier dysfunction in acute lung injury

Vascular hyperpermeability drives the pathogenesis of acute lung injury (ALI) during sepsis. Although γ-aminobutyric acid type A receptors (GABAARs) are classically recognized as central nervous system ion channels, we identified an unexpected, essential requirement for the GABAA receptor α1 subunit (GABRA1) in preserving pulmonary endothelial integrity. To investigate the translational relevance of our findings in vivo, we utilized a cecal ligation and puncture (CLP)-induced sepsis mouse model. Analysis of pulmonary microvascular endothelial cells (PMVECs) isolated from these septic mice revealed a profound depletion of GABRA1. This reduction was consistently observed in cultured endothelial cells following LPS challenge. Furthermore, targeted silencing of GABRA1 in Human Umbilical Vein Endothelial Cell (HUVEC) significantly exacerbated LPS-induced barrier dysfunction, as indicated by a marked decrease in transendothelial electrical resistance and increased expression of adhesion molecules (ICAM-1 and VCAM-1). These results suggest that GABRA1 may act as a regulatory element in the pulmonary vasculature, offering a potential therapeutic avenue for managing septic endothelial leakage. Two primary objectives guide this research on sepsis-induced ALI: first, to characterize the expression profile of GABAA receptor subunits (with a focus on α1) in endothelial cells; and second, to delineate the functional role of the α1 subunit in preserving endothelial barrier integrity and controlling the inflammatory response. We observed a significant downregulation of GABAA receptor α1 subunit in PMVECs during sepsis. Consequently, knocking down this subunit in endothelial cells worsened LPS-induced injury, manifesting as impaired barrier function (lower TEER) and enhanced inflammation (elevated ICAM-1/VCAM-1). These data collectively identify endothelial GABAA receptor α1 subunit as may function as a potential regulatory element in septic ALI, warranting further investigation as a therapeutic target.