A blocking monoclonal antibody to CCL24 alleviates liver fibrosis and inflammation in experimental models of liver damage

Background & aims: C-C motif chemokine ligand 24 (CCL24) is a chemokine that regulates inflammatory and fibrotic activities through its receptor, C-C motif Chemokine Receptor (CCR3). The aim of the study was to evaluate the involvement of the CCL24-CCR3 axis in liver fibrosis and inflammation and to assess the potential of its blockade, by a monoclonal anti-CCL24 antibody, as a therapeutic strategy for non-alcoholic steatohepatitis (NASH) and liver fibrosis.

Methods: Expression of CCL24 and CCR3 was evaluated in liver biopsies and blood samples. CCL24 involvement in NAFLD/NASH pathogenesis was assessed in Ccl24 knockout mouse using the methionine-choline deficient (MCD) diet experimental model. Antifibrotic and anti-inflammatory effects of CM-101 were tested in the MCD and STAM mouse models and in the thioacetamide (TAA) model in rats. Liver enzymes, liver morphology, histology and collagen deposition, as well as fibrosis- and inflammation-related protein expression were assessed. Activation of hepatic stellate cells (HSCs) was evaluated in the human LX2 cell line.

Results: Patients with NASH and advanced NAFLD exhibited significant expression of both CCL24 and CCR3 in liver and blood samples. In the experimental MCD-diet model, Ccl24 knockout mice showed an attenuated liver damage response compared to wild-type mice, exhibiting reduced histological NAFLD activity scores and fibrosis, as well as lower levels of liver enzymes. Blocking CCL24 using CM-101 robustly reduced liver damage in 3 experimental animal models (MCD, STAM and TAA), as demonstrated by attenuation of liver fibrosis and NAFLD activity score. Furthermore, blocking CCL24 by CM-101 significantly inhibited CCL24-induced HSC motility, α-SMA expression and pro-collagen I secretion.

Conclusion: Our results reveal that blocking CCL24 significantly attenuates liver fibrosis and inflammation and may have a potential therapeutic effect in patients with NASH and/or liver fibrosis.

Lay summary: CCL24 is a chemokine that regulates inflammation and fibrosis. It was found to be significantly expressed in patients with non-alcoholic steatohepatitis, in whom it regulates profibrotic processes in the liver. Herein, we show that blockade of CCL24 using a monoclonal antibody robustly attenuated liver fibrosis and inflammation in animal models, thus suggesting a potential therapeutic role for an anti-CCL24 agent.

ALT, alanine aminotransferase; AST, aspartate aminotransferase; Antibody; C-C motif chemokine ligand 24; CCL24; CCL24, C-C motif chemokine ligand 24; CCR3, C-C motif chemokine receptor 3; CM-101; Fibrosis; HSCs, hepatic stellate cells; IL-6, interleukin-6; MCD, methionine-choline deficient; MFI, median fluorescence intensity; MMP, matrix metallopeptidase; NAFLD, non-alcoholic fatty liver disease; NAS, NAFLD activity score; NASH, non-alcoholic steatohepatitis; Non-alcoholic fatty liver disease; Non-alcoholic steatohepatitis; PBMC, peripheral blood mononuclear cells; TAA, thioacetamide; WT, wild-type; α-SMA, α-smooth muscle actin.