title: Interaction in endothelium of non-muscular myosin light-chain kinase and the NF-κB pathway is critical to lipopolysaccharide-induced vascular hyporeactivity.
abstract: During sepsis, endothelial barrier dysfunction contributes to cardiovascular failure, mainly through the release of oxidative metabolites by penetrant leukocytes. We reported the non-muscular isoform of myosin light chain kinase (nmMLCK) playing a pivotal role in endotoxin shock injury associated with oxidative and nitrative stresses, and vascular hyporeactivity. The present study was aimed at understanding the molecular mechanism of lipopolysaccharide (LPS)-induced vascular alterations as well as studying a probable functional association of nmMLCK with nuclear factor κ-light-chain enhancer of activated B cells (NF-κB). Aortic rings from mice were exposed in vitro to LPS and, then, vascular reactivity was measured. Human aortic endothelial cells (HAoECs) were incubated with LPS, and interaction of nmMLCK with NF-κB was analysed. We provide evidence that nmMLCK deletion prevents vascular hyporeactivity induced by in vitro LPS treatment but not endothelial dysfunction in the aorta. Deletion of nmMLCK inhibits LPS-induced NF-κB activation and increases nitric oxide (NO) release via induction of inducible NO synthase (iNOS) within the vascular wall. Also, removal of endothelium prevented both NF-κB and iNOS expression in aortic rings. Among the proinflammatory factors released by LPS-treated endothelial cells, interleukin-6 accounts for the induction of iNOS on smooth muscle cells in response to LPS. Of particular interest is the demonstration that, in HAoECs, LPS-induced NF-κB activation occurs via increased MLCK activity sensitive to the MLCK inhibitor, ML-7, and physical interactions between nmMLCK and NF-κB. We report for the first time on NF-κB as a novel partner of nmMLCK within endothelial cells. The present study demonstrates a pivotal role of nmMLCK in vascular inflammatory pathologies.
authors.affiliation: LUNAM Université, INSERM, UMR 1063, Angers, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Recoquillon
authors.affiliation: LUNAM Université, INSERM, UMR 1063, Angers, France Seconda Università di Napoli, Dipartimento di Medicina Sperimentale, Naples, Italy.
authors.forename: Nunzia
authors.initials: N
authors.lastname: Carusio
authors.affiliation: LUNAM Université, INSERM, UMR 1063, Angers, France.
authors.forename: Anne-Hélène
authors.initials: AH
authors.lastname: Lagrue-Lakhal
authors.affiliation: LUNAM Université, INSERM, UMR 1063, Angers, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Tual-Chalot
authors.affiliation: Seconda Università di Napoli, Dipartimento di Medicina Sperimentale, Naples, Italy.
authors.forename: Amelia
authors.initials: A
authors.lastname: Filippelli
authors.affiliation: LUNAM Université, INSERM, UMR 1063, Angers, France Centre Hospitalo-Universitaire d'Angers, Angers, France.
authors.forename: Ramaroson
authors.initials: R
authors.lastname: Andriantsitohaina
authors.affiliation: LUNAM Université, INSERM, UMR 1063, Angers, France Centre Hospitalo-Universitaire d'Angers, Angers, France carmen.martinez@univ-angers.fr.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Martinez
mesh_terms: D000818:Animals; D001011:Aorta / Q000201:enzymology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000503:physiopathology; D006801:Humans; D066298:In Vitro Techniques; D008070:Lipopolysaccharides; D008297:Male; D018345:Mice, Knockout; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018805:Sepsis / Q000201:enzymology* / Q000503:physiopathology
chemical_list: D008070:Lipopolysaccharides; D016328:NF-kappa B; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D009219:Myosin-Light-Chain Kinase; C000593292:non-muscle myosin light-chain kinase, human; C561451:non-muscle myosin light-chain kinase, mouse
keywords: NF-κB; inflammation; lipopolysaccharide; nitric oxide; nmMLCK