Emerging role of FUS in TGFB1 and COL1A1 transcription dependent on GADD45B to induce NASH-fibrosis

Area of Science:

• Molecular Biology
• Hepatology
• Cell Biology

Background:

• Fused in sarcoma (FUS) is a DNA-RNA binding protein influencing gene transcription.
• The role of FUS in non-alcoholic steatohepatitis (NASH)-fibrosis remains largely uncharacterized.
• Understanding FUS and its interactions is crucial for developing NASH-fibrosis therapies.

Purpose of the Study:

• To investigate the role of FUS in NASH-fibrosis.
• To explore the relationship between FUS and growth arrest and DNA damage 45β (GADD45B) in hepatic stellate cells (HSCs).
• To evaluate FUS and GADD45B as potential therapeutic targets for NASH-fibrosis.

Main Methods:

• Immunohistochemistry and Western blot analysis of FUS expression in NASH patient liver samples and LX-2 cells.
• Immunofluorescence staining to assess FUS and GADD45B co-localization in HSCs.
• Chromatin immunoprecipitation, qPCR, luciferase assays, and Gadd45b knockout mouse models to analyze FUS binding and transcriptional activity.

Main Results:

• FUS co-localizes with GADD45B in HSCs.
• FUS directly binds to and regulates the promoters of TGFB1 and COL1A1.
• Gadd45b knockout mice exhibited reduced HSC activation, collagen deposition, and nuclear FUS content in a NASH-fibrosis model.

Conclusions:

• FUS plays a significant role in regulating HSC activation and extracellular matrix deposition in NASH-fibrosis.
• GADD45B is a key mediator in FUS-driven HSC activation and fibrosis progression.
• FUS and GADD45B represent promising therapeutic targets for treating NASH-fibrosis.