Disrupting mitochondrial β-oxidation by depletion of HADHA impairs primary ciliogenesis.

Primary cilia are dynamic signaling hubs essential for cell homeostasis, and defects in ciliogenesis underpin various genetic disorders. Alpha-hydroxyacyl-CoA dehydrogenase (HADHA), a subunit of the mitochondrial trifunctional enzyme, is crucial for long-chain fatty acid β-oxidation and acetyl-CoA production. Although it was recently demonstrated that lipid metabolism modulates primary ciliogenesis, the connection between mitochondrial β-oxidation and primary cilia remains largely unexplored. Here, we report that HADHA dysfunction markedly impairs primary ciliogenesis and disrupts cilia-dependent signaling. Loss of HADHA reduces both ciliary frequency and length, accompanied by decreased levels of key ciliary signaling mediators. Reintroduction of wild-type HADHA in HADHA knockout cells rescues these defects, whereas its dehydrogenase deficiency mutant (E510Q) fails to restore either normal cilia formation or ciliary signaling. Notably, supplementation with sodium acetate, which resupplies intracellular acetyl-CoA, effectively rescues primary cilium in HADHA-deficient cells. Importantly, this acetate-mediated rescue implicates a potential therapeutic strategy for HADHA-related disorders, supporting the translational relevance of modulating acetyl-CoA levels to restore ciliary function. These findings suggest a relevant link between mitochondrial β-oxidation and primary ciliogenesis, highlighting acetyl-CoA as a potential therapeutic target for disorders related to HADHA deficiency.