Unexpected Pro-Fibrotic Effect of MIF in Non-Alcoholic Steatohepatitis Is Linked to a Shift in NKT Cell Populations

Area of Science:

• Hepatology
• Immunology
• Molecular Biology

Background:

• Macrophage migration inhibitory factor (MIF) exhibits anti-fibrotic and anti-steatotic effects in certain liver injury models.
• Non-alcoholic fatty liver disease (NAFLD) progression is often linked to liver fibrosis.
• The role of MIF in NAFLD-associated liver fibrogenesis requires further elucidation.

Purpose of the Study:

• To investigate the function of MIF in NAFLD-associated liver fibrogenesis.
• To determine the cellular mechanisms by which MIF influences liver fibrosis in NAFLD.
• To explore the correlation between MIF, NKT cells, and fibrosis in human NAFLD patients.

Main Methods:

• Utilized mouse models (wild-type, Mif-/-, Mif-Δ) fed a NASH diet.
• Employed molecular, histological, and immunological analyses in vitro and in vivo.
• Analyzed liver tissues and cells from mice and human NASH patients.

Main Results:

• Hepatic Mif expression was induced by NASH diet in wild-type mice but not Mif-Δ mice.
• MIF deficiency significantly abrogated NASH diet-induced liver fibrogenesis in mice.
• MIF promoted the accumulation of pro-fibrotic type-I NKT cells in NAFLD models.
• Fibrosis markers correlated with MIF and type-I NKT cell markers in human NASH patients.

Conclusions:

• Hepatocytes are a major source of MIF during chronic metabolic liver injury.
• MIF contributes to NAFLD progression by promoting liver fibrogenesis.
• MIF skews NKT cell polarization towards a pro-fibrotic phenotype in NAFLD, highlighting its context-dependent role.