HDAC6 inhibitors(Sungkyunkwan University)

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.

HDAC6 is integral to the regulation of primary cilia, which are specialized structures that serve as crucial signaling hubs for cellular communication and environmental response. These ciliary functions are essential for maintaining cellular homeostasis and orchestrating developmental processes. Dysregulation of HDAC6 activity is implicated in ciliopathies, a group of disorders characterized by defective ciliary structure or function, resulting in widespread organ involvement and significant morbidity. This review provides a comprehensive examination of the molecular dynamics of HDAC6 in the context of ciliogenesis and ciliopathies, emphasizing its dual role in the deacetylation of microtubules and regulation of the ciliary axoneme. Furthermore, HDAC6 interacts with key signaling molecules, modulating processes ranging from cell cycle regulation to inflammatory responses, which highlights its central role in cellular physiology and pathology. The therapeutic potential of HDAC6 inhibitors has been explored, with promising results in various disease models, including retinal and renal ciliopathies, highlighting their ability to restore normal ciliary function. This analysis not only underscores the critical importance of HDAC6 in maintaining ciliary integrity but also illustrates how targeting the HDAC6‐cilia axis could provide a groundbreaking approach to treating these complex disorders. In doing so, this review sets the stage for future investigations into HDAC6‐targeted therapies, potentially transforming the clinical management of ciliopathies and significantly improving patient outcomes.