Histone deacetylase 7 mediates lipopolysaccharide-inducible mitochondrial fission in macrophages

Histone deacetylase 7 (HDAC7) drives several immunometabolism-related processes in macrophages including lipopolysaccharide (LPS)-inducible glycolysis and inflammatory mediator production. Using an advanced biotin ligase TurboID system in human macrophages, we report 104 candidate HDAC7 interaction partners that might contribute to its immunometabolic functions. One such protein is the mitochondrial fission-promoting GTPase dynamin-related protein 1 (DRP1, also known as DNM1L), which associates with HDAC7 in cells. Using gain- and loss-of-function genetic approaches, we show that HDAC7 promotes LPS-inducible mitochondrial fission in macrophages, as well as DRP1-dependent metabolic and inflammatory responses. HDAC7 enzymatic activity was dispensable for LPS-inducible fission, as previously reported for LPS-inducible glycolysis. However, a pharmacological inhibitor of HDAC7 attenuated fission in primary human and mouse macrophages, implicating its acetyl-lysine docking function in this response. HDAC7 thus drives inducible mitochondrial fission in macrophages. Small molecules targeting the acetyl-lysine docking function of HDAC7 might have applications in preventing pathological processes driven by dysregulated mitochondrial fission.