Balance Between EGF/STAT1 and IFNγ/NRF2 Signaling Controls ECM1 Expression and Determines Hepatic Homeostasis versus Chronic Liver Disease

Abstract In healthy livers, extracellular matrix protein 1 (ECM1) is essential for liver homeostasis by keeping latent transforming growth factor-β (LTGF-β) quiescent. Upon hepatocyte damage, ECM1 is downregulated, facilitating LTGF-β activation and fibrogenesis. However, little is known about how hepatic ECM1 is regulated. Here we found in healthy hepatocytes, EGF/EGFR signaling sustains ECM1 expression through phosphorylating STAT1 at S727, enhancing its binding to the ECM1 promoter and boosting gene transcription. During liver inflammation, accumulating IFNγ disrupts this process by downregulating EGFR and inhibiting EGF/EGFR/STAT1-mediated ECM1 promoter binding. Mechanistically, IFNγ-induced STAT1 phosphorylation at Y701 impairs the binding of p-STAT1 S727 to the ECM1 promoter. Additionally, IFNγ induces NRF2 nuclear translocation, which repressively binds to the ECM1 promoter, further reducing its expression. These findings were confirmed in several chronic liver disease (CLD) mouse models. Moreover, AAV8-ECM1 significantly attenuates liver fibrosis and injuries in Western diet (WD)-fed mice. Notably, in patients with CLD, ECM1 levels align with EGFR expression, while NRF2 and LTGF-β activation show a negative correlation with both. Competing Interest Statement The authors have declared no competing interest. Footnotes The immunofluorescence figures were modified by adding the name of the target molecules in all figures. Abbreviations - ADAMTS1 - A disintegrin and metalloproteinase with thrombospondin motifs 1 - BDL - Bile duct ligation - BW - Body weight - CCl4 - Carbon tetrachloride - CD - Chow diet - CD-HFD - Choline-deficient high-fat diet - ChIP - Chromatin immunoprecipitation - CLD - Chronic liver disease - CYP1B1 - cytochrome P450 family 1 subfamily B member 1 - DDC - 3,5-diethoxycarbonyl-1,4-dihydrocollidine - ECM1 - Extracellular matrix protein 1 - EGF - Epidermal growth factor - EGFR - Epidermal growth factor receptor - GEO - Gene Expression Omnibus - H2O2 - Hydrogen peroxide - HBV - Hepatitis-B-virus - HCC - Hepatocellular carcinoma - HPHs - Human primary hepatocytes - HSCs - Hepatic stellate cells - IF - Immunofluorescence - IFNγ - Interferon gamma - IHC - Immunohistochemistry - i.p. - Intraperitoneal - KEAP1 - Kelch-like ECH-associated protein 1 - LAP - Latency-associated peptide - LTGF-β - Latent TGF-β - MELD - Model for End-Stage Liver Disease - MMP - Matrix metalloproteinase - MPHs - Mouse primary hepatocytes - MASLD - Metabolic dysfunction-associated steatotic liver disease - MASH - Metabolic dysfunction-associated steatohepatitis - NQO1 - NAD(P)H:quinone oxidoreductase 1 - NRF2 - Nuclear factor erythroid 2-related factor 2 - OPZ - Oltipraz - PSR - Picrosirius Red - qRT-PCR - Quantitative real-time PCR - ROS - Reactive oxygen species - scRNA-seq - single-cell RNA sequencing - siRNA - Small interfering RNA - S727 - TSP-1 TSS - Serine727 - Thrombospondin 1 Transcription start site - UMAP - Uniform manifold approximation and projection - WD - Western diet - Y701 - Tyrosine701