Inhibiting nonmuscle myosin II impedes inflammatory infiltration and ameliorates progressive renal disease

Abstract

The motor protein nonmuscle myosin II (NMII) through its interaction with the actin cytoskeleton constitutes the machinery of cell crawling and has an important role in driving locomotion and infiltration of immune competent cells during inflammatory response and immune reaction. Blebbistatin is a highly selective inhibitor of NMII adenosine triphosphatase. This study examined the effect of NMII inhibition by blebbistatin on inflammation. In vitro, blebbistatin markedly induced actinomyosin complex disassembly in various cultured immunocytes, and functionally impaired their motile activity and invasive capacity as assessed by the Boyden chamber motility assay and the matrigel invasion assay. In vivo, in a rat model of acute inflammation induced by tumor necrosis factor, blebbistatin obliterated renal sequestration of circulating fluorescence-labeled macrophages in a dose-dependent fashion. Moreover, in rats with progressive obstructive nephropathy, blebbistatin treatment exhibited a remarkable renoprotective effect, as evidenced by normalized kidney weight, improved gross morphology, and diminished histologic injury in the tubulointerstitium. This beneficial effect was associated with significant amelioration of renal inflammation, consistent with a primary antiinflammatory action by blebbistatin. In addition, in rats with established obstructive nephropathy, blebbistatin pretreated macrophages showed obliterated recruitment into the inflamed renal parenchyma, denoting that blebbistatin directly impedes inflammatory infiltration by immunocytes. Collectively, our findings suggest that inhibition of NMII has a potent and direct anti-inflammatory effect on the basis of impairment of the actinomyosin powered locomotive machinery, which is essential for migration and infiltration of immune competent cells.

Hydroxyfasudil-Mediated Inhibition of ROCK1 and ROCK2 Improves Kidney Function in Rat Renal Acute Ischemia-Reperfusion Injury

“…The importance of cell migration for inflammatory responses was supported recently [33]. Inhibition of the motor protein non-muscle myosin II which impairs the actinomyosin powered locomotive machinery improves the progression of experimental obstructive nephropathy which serves as a model of progressive renal disease mainly by its potent anti-inflammatory effect [58]. In a model of hypertensive nephropathy inhibition of lymphocyte migration limited histological and molecular fibrosis without affecting increased systemic blood-pressure [59].…”

The Actin Cytoskeleton as a Therapeutic Target for the Prevention of Relapse to Methamphetamine Use

“…For instance, not only does Blebb lack NMII isoform selectivity, but it also hits skeletal, smooth and, perhaps, cardiac muscle myosin IIs. However, in silico assessments indicate that Blebb should have high brain penetrance and it has been shown to be tolerated by rodents when delivered intravenously [66]. Given that Blebb was found through a relatively small-scale screen, the potential for improving Blebb through derivitization and/or identifying novel NMII inhibitors remains high [65].…”

“…Indeed, myosin II represents an attractive therapeutic target because its distribution is more tissue-specific, with the NMII isoforms being abundantly expressed within the CNS, including the AMY. Further, systemic inhibition with Blebb is tolerated by rodents [66]. An additional benefit of our discovery, from a safety perspective, is that it appears a single manipulation of the actin cytoskeleton is efficacious.…”

Small-Molecule Inhibitors of Myosin Proteins

“…For example, the anti-inflammatory effects of blebbistatin-based myosin II inhibition have been shown to ameliorate progressive renal disease in a rat model [75]. Furthermore, the fact that blebbistatin is phototoxic to human cancer cells under exposure to blue light [76] and blocks the invasiveness of both MCF-7 breast cancer cells [77] and pancreatic adenocarcinoma cells [78] targets this molecule as a lead for anticancer agent development.…”