Rho-kinase inhibition is beneficial in fibrosis

Exogenous extracellular matrix proteins decrease cardiac fibroblast activation in stiffening microenvironment through CAPG

Controlling fibrosis is an essential part of regenerating the post-ischemic heart. In the post-ischemic heart, fibroblasts differentiate to myofibroblasts that produce collagen-rich matrix to physically stabilize the infarct area. Infarct models in adult mice result in permanent scarring unlike newborn animals which fully regenerate. Decellularized extracellular matrix (dECM) hydrogels derived from early-aged hearts have been shown to be a transplantable therapy that preserves heart function and stimulates cardiomyocyte proliferation and vascularization. In this study, we investigate the anti-fibrotic effects of injectable dECM hydrogels in a cardiac explant model in the context of age-associated tissue compliance. Treatments with adult and fetal dECM hydrogels were tested for molecular effects on cardiac fibroblast activation and fibrosis. Altered sensitivity of fibroblasts to the mechanosignaling of the remodeling microenvironment was evaluated by manipulating the native extracellular matrix in explants and also with elastomeric substrates in the presence of dECM hydrogels. The injectable fetal dECM hydrogel treatment decreases fibroblast activation and contractility and lowers the stiffness-mediated increases in fibroblast activation observed in stiffened explants. The anti-fibrotic effect of dECM hydrogel is most observable at highest stiffness. Experiments with primary cells on elastomeric substrates with dECM treatment support this phenomenon. Transcriptome analysis indicated that dECM hydrogels affect cytoskeleton related signaling including Macrophage capping protein (CAPG) and Leupaxin (LPXN). CAPG was down-regulated by the fetal dECM hydrogel. LPXN expression was decreased by stiffening the explants; however, this effect was reversed by dECM hydrogel treatment. Pharmacological disruption of cytoskeleton polymerization lowered fibroblast activation and CAPG levels. Knocking down CAPG expression with siRNA inhibited fibroblast activation and collagen deposition. Collectively, fibroblast activation is dependent on cooperative action of extracellular molecular signals and mechanosignaling by cytoskeletal integrity.

Fasudil prevents liver fibrosis via activating natural killer cells and suppressing hepatic stellate cells

BACKGROUND

Fasudil, as a Ras homology family member A (RhoA) kinase inhibitor, is used to improve brain microcirculation and promote nerve regeneration clinically. Increasing evidence shows that Rho-kinase inhibition could improve liver fibrosis.

AIM

To evaluate the anti-fibrotic effects of Fasudil in a mouse model of liver fibrosis induced by thioacetamide (TAA).

METHODS

C57BL/6 mice were administered TAA once every 3 d for 12 times. At 1 wk after induction with TAA, Fasudil was intraperitoneally injected once a day for 3 wk, followed by hematoxylin and eosin staining, sirius red staining, western blotting, and quantitative polymerase chain reaction (qPCR), and immune cell activation was assayed by fluorescence-activated cell sorting. Furthermore, the effects of Fasudil on hepatic stellate cells and natural killer (NK) cells were assayed in vitro.

RESULTS

First, we found that TAA-induced liver injury was protected, and the positive area of sirius red staining and type I collagen deposition were significantly decreased by Fasudil treatment. Furthermore, western blot and qPCR assays showed that the levels of alpha smooth muscle actin (α-SMA), matrix metalloproteinase 2 (MMP-2), MMP-9, and transforming growth factor beta 1 (TGF-β1) were inhibited by Fasudil. Moreover, flow cytometry analysis revealed that NK cells were activated by Fasudil treatment in vivo and in vitro. Furthermore, Fasudil directly promoted the apoptosis and inhibited the proliferation of hepatic stellate cells by decreasing α-SMA and TGF-β1.

CONCLUSION

Fasudil inhibits liver fibrosis by activating NK cells and blocking hepatic stellate cell activation, thereby providing a feasible solution for the clinical treatment of liver fibrosis.