Pharmacological manipulation of liver fibrosis progression using novel HDAC 6 inhibitors

Chronic liver injury characterized by unresolved hepatitis leads to fibrosis, potentially progressing to cirrhosis and hepatocellular carcinoma. Effective treatments for halting or reversing liver fibrosis are currently lacking. This study investigates the potential of HDAC6 as a therapeutic target in liver fibrosis. We synthesized two selective HDAC6 inhibitors, DR-3 and FDR2, and assessed their effects on hepatic stellate cell (HSC) activation and liver fibrosis using human precision cut liver slices (hPCLS). Molecular docking, deacetylation inhibition assays, and various cellular assays were employed to evaluate the specificity and anti-fibrotic efficacy of these inhibitors. DR-3 and FDR2 demonstrated high selectivity for HDAC6 over HDAC1, significantly inhibiting HSC activation markers and fibrogenic gene expression. Both inhibitors increased acetylation of α-tubulin and suppressed TGF-β1-induced SMAD signaling in HSCs. In human precision cut liver slices (hPCLS), DR-3 and FDR2 reduced fibrogenic protein levels and collagen deposition. The selective inhibition of HDAC6 by DR-3 and FDR2 effectively reduces HSC activation and fibrogenesis in liver models, supporting further investigation of HDAC6 inhibitors as potential anti-fibrotic therapies.