Function Of Glycolytic Enzymes Research Articles

Abstract 338: Limited Reduction of Heart Rate Promotes Cardiac Regeneration by Switching the Energy Metabolic Mode in Cardiomyocytes

Aims: Lack of cardiac regeneration with robust fibrosis response to the acute myocardial injury is the main obstacle to clinical treatment of cardiovascular diseases in humans. Stimulating the proliferation of endogenous cardiomyocytes (CMs) and replacing the scarred tissue with new functional CMs is a potential therapeutic strategy to the patients with heart failure. Heart rate reduction (HRR) is regarded as an effective clinical treatment for myocardial infarction. However, the mechanism of HRR promoting the recovery of cardiac function after injury still remains controversial, and whether there is any endogenous CM proliferation induced by HRR is undefined. Methods and results: The beating of CMs was reduced in vitro and heart rate (HR) of adult mice and different animal models of myocardial injury were modulated by six antiarrhythmic drugs to determine the role of HR in CM proliferation and cardiac repair. RNA-seq, extracellular flux analysis, metabolic flux analysis, and metabonomics were used to study the CM metabolism after HR modulation. We verified that reducing the beating can induce CM proliferation both in vitro and in vivo physiologically, and HRR also promoted cardiac regenerative repair after myocardial injury as well, reversely, increasing HR showed the opposite effect. Mechanistically, HRR reduced energy metabolism requirements and total ATP production of CMs but switched energy metabolic mode that the proportion of ATP production from aerobic glycolysis was increased, while from fatty acid oxidation was decreased. The switching of energy metabolic mode in CMs occurred in synchrony with the changes of glycolytic enzymes activities, these enzymes, including PFKFB3, PKM2, GAPDH, induced G1/S transition for cell cycle re-entry of CMs by upregulating the expression of cyclin D and CDK4/6 and facilitate substrates into the biomass needed to produce a new cell by biosynthesis. This coordinating function of glycolytic enzymes contributed to CM proliferation. Conclusion: Together, these results demonstrate that reduction of heart rate promotes CM proliferation by switching the energy metabolic mode, and highlight the potential therapeutic role of HRR in regenerative medicine.

Identification of S-nitrosylated proteins in postmortem pork muscle using modified biotin switch method coupled with isobaric tags

The objective of this study was to identify the S-nitrosylated proteins in aging samples of pork longissimus thoracis muscle (aged 0 and 3 d) and to study the effects of exogenous S-nitrosoglutathione (GSNO, concentration at 10 and 100 μM) treatments of aged 0 d sample. After validating modified biotin switch method, the samples were labeled with tandem mass tags (TMT126-129) for the LC-MS/MS analysis. A total of 366 peptides were identified to be S-nitrosylated corresponding to 339 proteins. Comparison of total intensity and individual S-nitrosylated sites between aging samples revealed that S-nitrosylation did occur in pork muscle during postmortem aging through possible pathways of denitrosylation and transnitrosylation. GSNO treatment groups showed a considerable number of potential cysteines could be modified with high thiol-reactivity. It was deduced that S-nitrosylation could be involved in the postmortem metabolic process possibly through the regulation of activity or function of glycolytic enzymes, calcium release, heat shock proteins, antioxidant enzymes and myofibrillar proteins.