Activation of Endothelial Pro-resolving Anti-Inflammatory Pathways by Circulating Microvesicles from Non-muscular Myosin Light Chain Kinase-Deficient Mice

Abstract

Microvesicles, small membrane vesicles released from cells, have beneficial and/or deleterious effects in sepsis. We previously reported that non-muscle myosin light chain kinase (nmMLCK) deletion protects mice against endotoxic shock by reducing inflammation. Here, we have evaluated the consequences of nmMLCK deletion on microvesicle phenotypes and their effects on mouse aortic endothelial cells in association with vascular inflammation and endothelial dysfunction during endotoxic shock induced by lipopolysaccharide in mice. Treatment with lipopolysaccharide induced an increase in levels of circulating microvesicles in wild type but not in nmMLCK-deficient mice. Microvesicles from nmMLCK-deficient mice (MVsnmMLCK-/-) prevented the inflammatory effects of lipopolysaccharide with concomitant increase of anti- inflammatory and reduction of pro-inflammatory secretome in mouse aortic endothelial cells. In addition, MVsnmMLCK-/- reduced the efficacy of lipopolysaccharide to increase aortic oxidative and nitrosative stresses as well as macrophage infiltration in the aorta. Moreover, MVsnmMLCK-/- prevented ex vivo endothelial dysfunction, vascular hyporeactivity, and in vivo overproduction of nitric oxide in heart and liver in response to lipopolysaccharide. Altogether, these findings provide evidence that nmMLCK deletion generates circulating microvesicles displaying protective effects by activating endothelial pro-resolving anti-inflammatory pathways allowing the effective down-regulation of oxidative and nitrative stresses associated with endotoxic shock. Thus, nmMLCK plays a pivotal role in susceptibility to sepsis via the control of cellular activation and release of circulating microvesicles.

Nonmuscle Myosin Light Chain Kinase: A Key Player in Intermittent Hypoxia‐Induced Vascular Alterations

“…19,48 More recently, we demonstrated that the protective effect of nmMLCK deletion on the vascular wall could be mediated by circulating microvesicles, which were able to activate endothelial proresolving anti-inflammatory pathways, allowing prevention of endotoxic shock-induced oxidative and nitrative stresses. 49 Taken together, this study demonstrates that nmMLCK is a hallmark mediator of IH-induced functional and structural vascular dysfunctions (ie, hypertension, arterial stiffening, and remodeling), through the inhibition of most of their determinants (ie, endothelial dysfunction, oxidative stress, and inflammation). Thus, nmMLCK and related signaling pathways could be considered as potential targets for the management of hypoxia-related vascular complications in OSA.…”

Extracellular vesicles and their effect on vascular haemodynamics: a systematic review

“…PFP-derived EVs from patients with Crohn’s disease, an inflammatory condition of the bowel, were demonstrated to impair both acetylcholine-mediated endothelium-dependent vasodilation and flow-mediated vasodilation in the mesenteric arteries after intravenous injection in mice for 24 h [ 53 ]. One study evaluated the platelet-free plasma EVs from a nmMLCK (non-muscular myosin light chain kinase) knockout mouse model prevention of endothelial dysfunction and impaired endothelium-dependent vasodilation and endothelium-independent vasoconstriction induced by lipopolysaccharide [ 54 ]. These workers found that EVs from wild-type mice were able to partially prevent the impaired vasoconstriction and vasodilatory responses while EVs from nmMLCK knock out mice had a larger effect [ 54 ].…”

“…One study evaluated the platelet-free plasma EVs from a nmMLCK (non-muscular myosin light chain kinase) knockout mouse model prevention of endothelial dysfunction and impaired endothelium-dependent vasodilation and endothelium-independent vasoconstriction induced by lipopolysaccharide [ 54 ]. These workers found that EVs from wild-type mice were able to partially prevent the impaired vasoconstriction and vasodilatory responses while EVs from nmMLCK knock out mice had a larger effect [ 54 ].…”

Genetic knockout of myosin light chain kinase (MLCK210) prevents cerebral microhemorrhages and attenuates neuroinflammation in a mouse model of vascular cognitive impairment and dementia

“…There are multiple MLCK proteins, but the focus of the present study is a 210-kDa MLCK protein encoded by the mylk1 genetic locus, referred to as MLCK210 (for review see Khapchaev and Shirinsky 2016). Prior studies on the role of MLCK210 in tissue barrier dysfunction and the potential of selective inhibitors have largely focused on non-CNS disorders (for recent reviews see Cunningham and Turner 2012; Rigor et al 2013; Khapchaev and Shirinsky 2016; Xiong et al 2017), including acute lung injury models (Wainwright et al 2003; Rossi et al 2007; Mirzapoiazova et al 2011; Usatyuk et al 2012; Fazal et al 2013; Wang et al 2014; Wang et al 2016; Zhou et al 2015), burn injury (Reynoso et al 2007; Guo et al 2012; Zahs et al 2012), acute diarrhea (Clayburgh et al 2005; Clayburgh et al 2006), endotoxic shock (Ralay Ranaivo et al 2007; Gaceb et al 2016), cardiovascular shear stress (Ohlmann et al 2005), atherosclerosis (Sun et al 2011), hypoxia (Arnaud et al 2018), and intestinal injury models (Al-Sadi et al 2012; Gilbert et al 2012; Wu et al 2014; Lorentz et al 2017; Nighot et al 2017; Al-Sadi et al 2019). Additionally, there exists a smaller literature exploring the benefit of inhibition of MLCK in the context of BBB dysfunction.…”