Upregulated miR‐144‐3p Attenuates LPS‐induced Acute Lung Injury via Inhibition of ROCK1 Signaling Pathway

Abstract

Dysfunctional endothelial cell (EC) barrier and increased lung vascular permeability is a cardinal feature of Acute Lung Injury (ALI) and sepsis that may results in a pathophysiological condition characterized by alveolar flooding and pulmonary edema and subsequent hypoxemia. In lung ECs, activation of Rho associated kinase‐1 (ROCK1) phosphorylates myosin light chain (MLC), stress fiber formation and hyper‐permeability during ALI. The role of MicroRNA‐144 (miR‐144) has been well investigated in many human diseases including cardiac ischaemia/reperfusion‐induced injury, lung cancer and lung viral infection, however, its role in pulmonary EC barrier regulation remains obscure. Here, we investigated miR‐144 mediated mechanism in the protection of endothelial barrier function in bacterial wall lipopolysaccharide‐(LPS) induced lung injury model. By using transwell endothelial permeability assay to examine in vitro permeability and immunofluorescence microscopy to determine barrier integrity, we showed that ectopic expression of miR‐144 effectively blocked human lung EC barrier disruption and hyper‐permeability in response to LPS. Furthermore, using a gain and loss of function strategy, overexpression of miR‐144 significantly decreased ROCK1 expression. Concomitantly miR‐144 inhibits ROCK1 mediated phosphorylation of MLC phosphatase and thus phosphorylation of MLC to counteract actin stress fibers formation in LPS activated human lung EC. Finally, in mice challenged with LPS, in vivo delivery of miR‐144 mimic via liposomes attenuated endotoxemia‐induced increased in lung wet‐to‐dry ratio, vascular permeability and inflammatory cytokines. In conclusion, our data suggest miR‐144 attenuates activation of the inflammatory ROCK1/MLC pathway in vascular EC is a promising therapeutic strategy to counter inflammatory lung injury.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.