Metabolic-associated fatty liver disease (MAFLD) is the most common chronic liver disease globally, characterized by excessive lipid accumulation. Insulin resistance (IR) is a fundamental pathogenic factor in MAFLD. However, there are currently no approved specific therapeutic drugs. Farnesol is a novel compound with antioxidant and anti-inflammatory effects that has recently attracted attention for its hepatoprotective properties. Here, researchers used network pharmacology to predict that protein tyrosine phosphatase non-receptor type 1 (PTPN1) might be a potential target of farnesol in the liver. Subsequently, they found that farnesol improved insulin sensitivity and glucose tolerance in MAFLD mice. Furthermore, farnesol alleviated lipid accumulation by binding to PTPN1 and reducing the dephosphorylation of the insulin receptor (INSR) in HepG2 cells and MAFLD mice. Consequently, the phosphatidylinositol 3-kinase/serine/threonine protein kinase (PI3K/AKT) signaling pathway was activated, leading to decreased levels of downstream proteins. In summary, these studies demonstrate that farnesol alleviates insulin resistance and hepatic steatosis in MAFLD by targeting PTPN1.
To elucidate the precise mechanism by which farrerol reduces lipid accumulation in hepatocytes, researchers conducted experiments using HepG2 cells. The results showed that farrerol supplementation reduced PAOA-induced lipid accumulation in HepG2 cells (Figure 1A). Furthermore, consistent with these results, PTPN1-overexpressing HepG2 cells exhibited more severe lipid accumulation under PAOA stimulation compared to the control group. Subsequent Western blot analysis results were consistent with the above findings, indicating that farrerol significantly increased the phosphorylation levels of INSR and PI3K-AKT, thereby restoring the insulin signaling pathway. However, it is noteworthy that this protective effect was abolished in PTPN1-overexpressing cells (Figure 1B-G). Therefore, farrerol exerts its effect of reducing PAOA-induced lipid droplet accumulation in HepG2 cells by interacting with PTPN1.
Figure 1. Farrerol reduces lipid accumulation in HepG2 cells treated with PAOA. (Gao J, et al., 2024)