Acetylation of fatty acid synthase regulates microglial lipid droplets accumulation and pro-inflammatory activity following traumatic brain injury.

Lipid droplet accumulation in microglia has been implicated in inflammatory functions associated with aging and demyelinating diseases. However, the molecular mechanisms driving lipid droplet formation under pathological conditions remain unrevealed. It is demonstrated herein that the acetylation of fatty acid synthase (FASN) plays a key regulatory role in the accumulation of lipid droplets in microglia following traumatic brain injury (TBI). Through mass spectrometry analysis, we identified hyperacetylation at lysine K673 of FASN as a critical driver of lipid droplet formation in microglia. Notably, this acetylation event not only promotes lipid droplet accumulation but also enhances pro-inflammatory cytokine production and phagocytic activity in microglia. Additionally, we found that HDAC3 may be the enzyme responsible for deacetylation of FASN K673. Importantly, observation of a mouse model carrying the FASN K673R mutation revealed a reduction in microglial lipid droplet accumulation and neuroinflammatory responses following TBI relative to wild-type mice. Thus, FASN acetylation is a pivotal regulator of post-TBI microglial lipid droplet formation and neuroinflammation. This positions the targeting of deacetylation pathways as a novel therapeutic strategy for TBI.