Therapeutic inhibition of inflammatory monocyte recruitment reduces steatohepatitis and liver fibrosis

Macrophages are key regulators of liver fibrosis progression and regression in nonalcoholic steatohepatitis (NASH). Liver macrophages comprise resident phagocytes, Kupffer cells, and monocyte-derived cells, which are recruited via the chemokine receptor CCR2. We aimed at elucidating the therapeutic effects of inhibiting monocyte infiltration in NASH models by using cenicriviroc (CVC), an oral dual chemokine receptor CCR2/CCR5 antagonist that is under clinical evaluation. Human liver tissue from NASH patients were analyzed for CCR2+ macrophages and administration of CVC was tested in mouse models of steatohepatitis, liver fibrosis progression and fibrosis regression. In human liver from n=17 patients and n=4 controls, CCR2+ macrophages increased parallel to NASH severity and fibrosis stage, with a concomitant inflammatory polarization of these CD68+, portal monocyte-derived macrophages (MoMF). Similar to human disease, we observed a massive increase of hepatic MoMF in experimental models of steatohepatitis and liver fibrosis. Therapeutic treatment with CVC significantly reduced the recruitment of hepatic Ly- 6C+ MoMF in all models. In experimental steatohepatitis with obesity, therapeutic CVC application significantly improved insulin resistance and hepatic triglyceride levels. In fibrotic steatohepatitis, CVC treatment ameliorated histological NASH activity and hepatic fibrosis. CVC inhibited the infiltration of Ly-6C+ monocytes, without direct effects on macrophage polarization, hepatocyte fatty acid metabolism or stellate cell activation. Importantly, CVC did not delay fibrosis resolution after injury cessation. RNA sequencing analysis revealed that MoMF, but not Kupffer cells, specifically upregulate multiple growth factors and cytokines associated with fibrosis progression, while Kupffer cells activated pathways related to inflammation initiation and lipid metabolism. In conclusion, pharmacological inhibition of CCR2+ monocyte recruitment efficiently ameliorates insulin resistance, hepatic inflammation and fibrosis, corroborating the therapeutic potential of CVC in patients with NASH. This article is protected by copyright. All rights reserved.