Decreased malonylation at the Aldolase A K108 site reduces its co-localization with actin, enhances AldoA enzymatic activity, and improves left ventricular contractile function in heart failure.
Decreased malonylation at the Aldolase A K108 site during heart failure enhances its enzymatic activity and improves heart function, revealing a novel metabolic regulatory mechanism in ischemic heart failure.
Abstract Background During the progression of heart failure, the primary substrate for ATP production shifts from fatty acids to glucose. Malonyl-CoA, an intermediate metabolite in de novo fatty acid synthesis, inhibits the enzymatic activity of carnitine palmitoyltransferase 1 and modulates protein function through lysine malonylation. However, the alterations in malonyl-CoA levels and the role of malonylation in cardiomyocytes during heart failure remain unknown. Methods Malonyl-CoA levels in the failing heart were assessed by LC-MS/MS. Proteomics analysis of malonylation modifications was conducted to identify proteins and specific sites exhibiting significant changes in malonylation during heart failure, with co-immunoprecipitation employed for confirmation. Cardiomyocyte-specific AAV9 viral vectors were constructed and injected intravenously in mice to overexpress AldoA, the AldoA K108Q mutant, which is unable to undergo malonylation, and the AldoA K108E mutant, which acts as a malonylation mimic. 28 days after ischemia/reperfusion injury, cardiac function was evaluated through echocardiography. LC-MS/MS was used to quantify the alterations in glycolysis intermediates and the TCA cycle in mice. In vitro, H9c2 cell lines were treated with 5, 10, and 25 µM malonyl-CoA, and immunofluorescence was performed to evaluate the co-localization of AldoA and actin. Results In the failing heart, malonyl-CoA levels and global malonylation were decreased. The expression of key enzymes involved in malonyl-CoA synthesis, ACC1 and ACSF3, was also reduced. In cardiomyocytes, malonylation was markedly decreased at 52 lysine sites in 46 proteins, with 66.7% of these proteins localized in the cytoplasm and 9.8% associated with glycolysis. Co-immunoprecipitation analysis confirmed a significant reduction in AldoA malonylation in failing cardiomyocytes, despite unchanged protein expression levels. Based on these findings, AldoA K108 was selected for further investigation. In ischemia/reperfusion-induced mouse model of heart failure, the AldoA K108Q mutant improved left ventricular contractile function. The levels of AldoA downstream metabolites, dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P), increased in heart tissue which suggested that malonylation at K108 may inhibit AldoA enzymatic activity. In vitro, increasing malonyl-CoA levels enhanced the co-localization of AldoA and actin, along with a lower amount of AldoA in the supernatant (free). Moreover, mitochondrial oxygen consumption rate was reduced with increased aldoA malonylation. Conclusion Our study reveals that the reduction of malonyl-CoA levels in cardiomyocytes leads to a global decrease in malonylation during heart failure. The decreased malonylation at the Aldolase A K108 site reduces its co-localization with actin, enhances AldoA enzymatic activity, and improves heart function.
Qiu et al. (Sat,) conducted a other in Ischemic heart failure. AldoA K108Q mutant (malonylation-deficient) via AAV9 vs. AldoA K108E mutant (malonylation mimic) was evaluated on Left ventricular contractile function and glycolysis intermediates. Decreased malonylation at the Aldolase A K108 site reduces its co-localization with actin, enhances AldoA enzymatic activity, and improves left ventricular contractile function in heart failure.