Abstract Body (Do not enter title and authors here): Background: Heart failure is marked by metabolic imbalance, leading to reduced mitochondrial ATP production. Ketone bodies, beyond serving as an alternative energy source, mitigate heart failure by reducing cardiac remodeling and inflammation. Emerging evidence highlights the role of long noncoding RNAs (lncRNAs) in regulating cardiac remodeling and mitochondrial metabolism. This study explores the effect of a ketogenic diet and ketotic conditions on cardiac lncRNA regulation and mitochondrial protection in both mouse and human cardiomyocytes.
Methods and Results: In a six-month study, 10-week-old male and female C57BL/6J mice were assigned to either a control diet (10% fat, 20% protein, 70% carbohydrate) or a ketogenic diet (Keto; 80% fat, 15% protein, 5% carbohydrate). The keto diet significantly raised blood ketone levels (n=36/group) and reduced heart mass relative to body weight, indicating cardiac metabolic adaptation. In keto hearts, lncRNA expression analysis via qPCR (n=13/group) revealed significant upregulation of lncRNA Malat1. A positive correlation between Malat1 and both Pgc1α (P=0.0018) and Nrf2 (P=0.0118) gene expression was also observed. Additionally, proteins involved in mitochondrial biogenesis and protection, including PGC1α and NRF2, were significantly elevated (n=6-10). In parallel, human AC16 cardiomyocytes were treated with β-hydroxybutyrate (BHB) at ketotic concentrations (0.5 mM, 1 mM, and 5 mM) for 24, 48, and 72 hours to simulate ketogenic conditions. BHB treatment upregulated the expression of MALAT1, alongside key genes for ketone oxidation such as MCT1, BDH1, and SCOT (n=3). Additionally, pyruvate dehydrogenase kinase, which inhibits glycolysis, was upregulated. The ketogenic condition also promoted the expression of mitochondrial biogenesis regulators (PGC1α, TFAM) and antioxidant defense genes (NRF2, SOD1, SOD2) (n=3). Furthermore, computational analysis using LncRRIsearch identified strong RNA-RNA interactions between MALAT1 and both PGC1α (-17.73 kcal/mol) and NRF2 (-19.42kcal/mol), suggesting potential post-transcriptional regulation by MALAT1.
Conclusion: In vivo and in vitro ketosis promote metabolic and mitochondrial adaptations by upregulating lncRNA MALAT1 and mitochondrial protective genes, suggesting a novel regulatory axis involving MALAT1, PGC1α, and NRF2. These findings highlight the therapeutic potential of ketotic interventions to promote mitochondrial function for heart failure treatment.