Pyruvate metabolism enzyme Dlat induces mitochondria protein hyperacetylation to limit fatty acid oxidation in the HFpEF heart

Increased protein acetylation is frequently observed in the failing heart, including in hearts with heart failure with preserved ejection fraction (HFpEF). However, the role of protein acetylation in cardiac metabolic impairments during the pathogenesis of HFpEF remains insufficiently investigated. In this study, a two-hit strategy, involving a high-fat diet and Nω-nitro-L-arginine methyl ester (L-NAME), was employed to induce the HFpEF model in mice. Significant cardiac diastolic dysfunction, pathological remodeling, and enhanced protein hyperacetylation were observed in the hearts of the two-hit HFpEF mice. Acetylome profiling revealed that the hyperacetylated proteins were predominantly localized to mitochondria and enriched in metabolic pathways, particularly in fatty acid oxidation (FAO). Furthermore, the HFpEF heart exhibited reduced FAO capacity and abnormal lipid accumulation. Activation of mitochondrial protein deacetylation restored FAO capacity and alleviated cardiac dysfunction in the HFpEF heart, whereas inhibition of mitochondrial deacetylase directly induced lipid metabolism disorders in cardiomyocytes. Notably, we identified Dlat, a pyruvate metabolism enzyme, as the key transacetylase responsible for mitochondrial protein hyperacetylation in the HFpEF heart. Overexpression of Dlat enhanced FAO-related protein acetylation and exacerbated cardiac lipid metabolism disturbances, thereby inducing pathological changes resembling the HFpEF phenotype. In contrast, Dlat knockdown effectively mitigated FAO inhibition and functional impairment in the two-hit HFpEF mice. Through discovery-driven approaches, we demonstrated that Dlat directly binds to the alpha subunit of mitochondrial trifunctional protein (HADHA) and triggers its acetylation at the K728 site, thereby inactivating HADHA enzymatic activity. Reactivating HADHA, either by cardiac-specific HADHA overexpression or oral administration of a biogenic polyamine, restored cardiac FAO capacity and prevented the development of HFpEF. Our study provides a mechanistic basis linking protein hyperacetylation, FAO inhibition, and the development of HFpEF. Activation of mitochondrial deacetylase or enhancement of cardiac FAO capacity may offer novel strategies for restoring cardiac metabolic homeostasis and function in HFpEF.