Targeting the liver clock improves fibrosis by restoring TGF-β signaling

Background & Aims: Liver fibrosis is the major driver of hepatocellular carcinoma and liver disease-related death. Approved antifibrotic therapies are absent and compounds in development have limited efficacy. Increased TGF-beta signaling drives collagen deposition by hepatic stellate cells (HSCs)/myofibroblasts. Here, we aimed to dissect the role of the circadian clock (CC) in controlling TGF-beta signaling and liver fibrosis. Methods: Using CC-mutant mice, enriched HSCs and myofibroblasts obtained from healthy and fibrotic mice in different CC phases and loss-of-function studies in human hepatocytes and myofibroblasts, we investigated the relationship between CC and TGF-beta signaling. We explored hepatocyte-myofibroblast communication through bioinformatic analyses of single-nuclei transcriptomes and performed validation in cell-based models. Using mouse models for MASH (metabolic dysfunction-associated steatohepatitis)-related fibrosis and spheroids from patients with liver disease, we performed proof-of-concept studies to validate pharmacological targetability and clinical translatability. Results: We discovered that the CC oscillator temporally gates TGF-beta signaling and this regulation is broken in fibrosis. We demonstrate that HSCs and myofibroblasts contain a functional CC with rhythmic expression of numerous genes, including fibrogenic genes. Perturbation studies in hepatocytes and myofibroblasts revealed a reciprocal relationship between TGF-beta activation and CC perturbation, which was confirmed in patient-derived ex vivo and in vivo models. Pharmacological modulation of CC-TGF-beta signaling inhibited fibrosis in mouse models in vivo as well as in patient-derived liver spheroids. Conclusion: The CC regulates TGF-beta signaling, and the breakdown of this control is associated with liver fibrosis in patients. Pharmacological proof-of-concept studies across different models have uncovered the CC as a novel therapeutic target for liver fibrosis - a growing unmet medical need. (c) 2024 European Association for the Study of the Liver. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.