Hexokinase-1 mitochondrial dissociation and protein O-GlcNAcylation drive heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) is a common cause of morbidity and mortality worldwide, but the underlying pathophysiology is not well-understood and treatment options are limited. Hexokinase-1 (HK1) mitochondrial-binding and protein O-GlcNAcylation are both altered in conditions with risk factors for HFpEF. Here we report a novel mouse model of HFpEF and show that HK1 mitochondrial-binding in endothelial cells (EC) is critical for the development of HFpEF. We demonstrate increased mitochondrial dislocation of HK1 in ECs from HFpEF mice. Mice with deletion of the mitochondrial-binding-domain of HK1 spontaneously develop HFpEF, and their ECs display impaired angiogenic potential. Mitochondrial-bound HK1 associates with dolichyl-diphosphooligosaccharide-protein-glycosyltransferase (DDOST) and its mitochondrial dislocation decreases protein N-glycosylation. We also show that the spatial proximity of dislocated HK1 and O-linked N-acetylglucosamine-transferase (OGT) increases protein O-GlcNAcylation by shifting the balance of the hexosamine-biosynthetic-pathway intermediate supply into the O-GlcNAcylation machinery. Pharmacological inhibition of OGT or EC-specific overexpression of O-GlcNAcase reverses angiogenic defects in ECs and the HFpEF phenotype, indicating that increased protein O-GlcNAcylation is responsible for the development of HFpEF. Our study demonstrates a new mechanism for HFpEF through HK1 cellular localization and resultant protein O-GlcNAcylation in ECs, and provides a potential new therapy for this disorder.