Targeting Circulating FABP4 Ameliorates Obesity-Associated Hepatic Steatosis.

Area of Science:

• Metabolic disease research
• Hepatology
• Adipose tissue biology

Background:

• Obesity is a primary cause of hepatic steatosis (fatty liver disease).
• The precise molecular mechanisms connecting obesity to liver lipid accumulation are not fully understood.
• Fatty acid-binding protein 4 (FABP4) is implicated in lipid metabolism, but its role in obesity-driven hepatic steatosis requires clarification.

Purpose of the Study:

• To investigate the role of circulating FABP4 in mediating lipid crosstalk between adipocytes and hepatocytes in obesity.
• To determine if FABP4 is a potential therapeutic target for obesity-associated hepatic steatosis.

Main Methods:

• Analysis of human liver tissues and mouse models of obesity and steatosis.
• Genetic deletion of FABP4 specifically in adipocytes.
• Development and testing of a neutralizing anti-FABP4 monoclonal antibody in obese mouse models.

Main Results:

• FABP4 protein, not its transcript, accumulates in hepatocytes during steatosis, suggesting an external source.
• Adipocyte-specific deletion of FABP4 prevented diet-induced hepatic steatosis without affecting overall obesity or systemic lipid levels.
• Circulating FABP4 directly binds to hepatocytes, enhancing free fatty acid uptake.
• Treatment with an anti-FABP4 antibody reduced FABP4 binding, suppressed fatty acid uptake, and attenuated hepatic steatosis in multiple models.

Conclusions:

• Circulating FABP4 acts as a critical mediator linking adiposity to hepatic steatosis by facilitating hepatocyte lipid uptake.
• Neutralizing FABP4 presents a promising therapeutic strategy for managing obesity-associated fatty liver disease.