Abstract
Cytokine storm is a hallmark for acute systemic inflammatory disease like sepsis. Intrinsic microbiome-derived short-chain fatty acid (SCFAs) like acetate modulates immune cell function and metabolism has been well studied. However, it remains poorly investigated about the effects and the underlying mechanism of exogenous acetate in acute inflammation like sepsis. Here, we observed that serum acetate accumulates in patients undergoing abdominal gastrointestinal surgery and in septic mice. Short exposure to high-dose exogenous acetate protects mice from sepsis by inhibiting glycolysis in macrophages, both in vivo and in vitro. Hypoxia-inducible factor 1 subunit alpha (HIF-1α) stabilization or overexpression reverses the decreased glycolysis and pro-inflammatory cytokine production in macrophages and abrogates acetate's protective effect in septic mice. Meanwhile, we also found acetyl-CoA synthetase-2, but not GPR41 or GPR43, plays a key role in acetate's immunosuppressive effect. Acetate transiently increases acetyl-coenzyme A production, promoting histone acetylation and decreasing acetyl-transfer to NF-κB p65. These findings suggest that short exposure to mM-level acetate inhibits macrophage immune response linked to HIF-1α-dependent glycolysis. Taken together, we demonstrate short-term exposure of exogenous acetate could regulate inflammatory responses through attenuating HIF-1α-dependent glycolysis.