During liver injury, intrahepatic macrophage compartment is augmented by circulating monocytes that infiltrate the liver driven by C-C motif chemokine ligand/C-C motif chemokine receptor (CCL/CCR) axis including CCL1‒CCR8 axis, thereby contributing to liver inflammation. Numerous small molecular receptor antagonists, including R243, have been developed for targeting CCR8; however, these agents face challenges in clinical translation, potentially attributed to their poor pharmacokinetic profiles, lack of target specificity, and potential adverse effects. In this study, we designed four CCR8 antagonizing peptides (AP8i-AP8iv) and performed molecular characterization in silico and therapeutic investigation in vitro and in vivo. Based on in silico docking, molecular dynamic simulation using homology build model and in-vitro (competitive) binding studies, AP8ii (YEWRFYHG) evidenced highly favorable and selective interactions at the CCR8-active site. AP8ii inhibited CCL1-driven chemotaxis and LPS/IFNγ-induced pro-inflammatory activation of monocytes-macrophages in vitro. In a CCl₄-induced acute liver injury mouse model, AP8ii treatment decreased intrahepatic infiltration of circulating monocytes. Moreover, AP8ii reduced liver inflammation, as indicated by decreased F4/80, IL6 and iNOS expression, diminished ALT levels, and attenuated fibrosis, as indicated by reduced collagen-I expression. In conclusion, we report a novel CCR8-antagonizing peptide that inhibited CCL1-driven intrahepatic monocytes infiltration and differentiation into pro-inflammatory phenotype, consequently ameliorating liver inflammation and fibrogenesis in an acute liver injury mouse model.

Tissue fibrosis, characterized by excessive accumulation of aberrant extracellular matrix (ECM) produced by myofibroblasts, is a growing cause of mortality worldwide. Understanding the factors that induce myofibroblastic differentiation is paramount to prevent or reverse the fibrogenic process. Integrin-mediated interaction between the ECM and cytoskeleton promotes myofibroblast differentiation. In the present study, we explored the significance of integrin alpha 11 (ITGA11), the integrin alpha subunit that selectively binds to type I collagen during tissue fibrosis in the liver, lungs and kidneys. We showed that ITGA11 was co-localized with α-smooth muscle actin-positive myofibroblasts and was correlatively induced with increasing fibrogenesis in mouse models and human fibrotic organs. Furthermore, transcriptome and protein expression analysis revealed that ITGA11 knockdown in hepatic stellate cells (liver-specific myofibroblasts) markedly reduced transforming growth factor β-induced differentiation and fibrotic parameters. Moreover, ITGA11 knockdown dramatically altered the myofibroblast phenotype, as indicated by the loss of protrusions, attenuated adhesion and migration, and impaired contractility of collagen I matrices. Furthermore, we demonstrated that ITGA11 was regulated by the hedgehog signaling pathway, and inhibition of the hedgehog pathway reduced ITGA11 expression and fibrotic parameters in human hepatic stellate cells in vitro, in liver fibrosis mouse model in vivo and in human liver slices ex vivo. Therefore, we speculated that ITGA11 might be involved in fibrogenic signaling and might act downstream of the hedgehog signaling pathway. These findings highlight the significance of the ITGA11 receptor as a highly promising therapeutic target in organ fibrosis.
Animals ; Collagen ; Collagen Type I ; Cytoskeleton ; Extracellular Matrix ; Fibrosis ; Hedgehogs ; Hepatic Stellate Cells ; Humans ; In Vitro Techniques ; Kidney ; Liver ; Liver Cirrhosis ; Lung ; Mice ; Mortality ; Myofibroblasts* ; Phenotype* ; Transcriptome ; Transforming Growth Factors