Geranylgeranyl Pyrophosphate Promotes Hepatic Lipid Accumulation by Prenylation of Perilipin4

Metabolically unhealthy obesity (MUO) is characterized by hepatic steatosis and type 2 diabetes (T2D), distinct from metabolically healthy obesity (MHO). This study aimed to identify the key regulator responsible for MUO.

Metabolomics analysis was conducted to compare hepatic metabolite profiles between individuals with MUO and MHO and mice. Geranylgeranyl pyrophosphate (GGPP) levels and its synthetase geranylgeranyl diphosphate synthase (GGPPS) were quantified in human and murine liver tissues. Hepatocyte-specific Ggpps knockout mice (LKO) were generated to evaluate the effects of GGPP deficiency on MUO-associated phenotypes. Mechanistic studies focused on GGPP-dependent prenylation of the lipid droplet-associated protein Perilipin4 and its role in lipid droplet formation. The therapeutic potential of DGBP, a GGPPS inhibitor, was also tested in MUO models.

GGPP and GGPPS protein expression were significantly elevated in the livers of patients with MUO and mice compared with counterparts with MHO. Hepatocyte-specific Ggpps knockout (LKO) mice exhibited reduced hepatic lipid accumulation, smaller lipid droplets, and improved insulin sensitivity, demonstrating GGPP's critical role in MUO pathogenesis. Mechanistically, GGPP promoted Perilipin4 prenylation, which enhanced large lipid droplet formation and exacerbated hepatic steatosis and insulin resistance. Pharmacologic inhibition of GGPPS with DGBP effectively attenuated MUO phenotypes, highlighting its therapeutic potential.

Hepatic GGPP drives MUO progression by facilitating Perilipin4 prenylation, thereby promoting pathological lipid droplet expansion and insulin resistance. Targeting GGPP with inhibitors of GGPPS like DGBP represents a promising strategy for treating MUO. These findings provide novel insights into the metabolic heterogeneity of obesity and potential therapeutic interventions for MUO-related complications.