MLKL Protects Pulmonary Endothelial Cells in Acute Lung Injury

Am J Respir Cell Mol Biol. 2024 Jan 11. doi: 10.1165/rcmb.2023-0207OC. Online ahead of print.ABSTRACTThe role of autophagy in pulmonary microvascular endothelial cell (PMVEC) are controversial in lipopolysaccharide (LPS)-induced ALI. Mixed lineage kinase domain like pseudokinase (MLKL) has been recently reported to keep cell survival by facilitating autophagic flux in response to starvation, rather than its well-recognized role in necroptosis. Using mouse PMVEC and LPS-induced ALI model, we showed that in PMVEC, MLKL was phosphorylated (p-MLKL) and autophagic flux was accelerated at the early stage of LPS stimulation (1-3 h), manifested by increases in levels of lipidated MAP1LC3B/LC3B (microtubule associated protein 1 light chain 3 beta; LC3-II), decreases in levels of SQSTM1/p62 (sequestosome 1), and fusion of autophagosome and lysosome by pHluorin-mKate2-human LC3 assay, which were all reversed by either MLKL inhibitor or siRNA MLKL. In mice, the inhibition of MLKL increased vascular permeability and aggravated mouse ALI upon 3-h LPS stimulation. The p-MLKL induced by short-term LPS formed multimers to facilitate the closure of phagophore by HaloTag-LC3 autophagosome completion assay. The charged multivesicular body protein 2A (CHMP2A) is essential in the process of phagophore closure into nascent autophagosome. Agreeing with the p-MLKL change, CHMP2A levels markedly increased during 1-3 h LPS stimulation. CHMP2A knockdown blocked autophagic flux upon LPS stimulation, wher...
Source: American Journal of Respiratory Cell and Molecular Biology - Category: Molecular Biology Authors: Source Type: research