Aged extracellular vesicles exacerbate myocardial ischemia-reperfusion injury via PTX3
L Sun, L Deng, Q W Chen, T T Sun, Q J Wang, R X WangAbstract
Background
Aging is an independent risk factor for exacerbating myocardial ischemia-reperfusion injury, yet the pathological role of aged circulating extracellular vesicles and their key molecular mechanisms remain elusive. This study integrates single-cell transcriptome sequencing and quantitative proteomics to systematically elucidate the mechanism by which aged EVs regulate myocardial energy metabolism and redox homeostasis.
Methods
Circulating EVs were isolated from the peripheral blood of young and aged rats, characterized by NTA, Western blot, and transmission electron microscopy, and validated for uptake by cardiomyocytes. A rat model of myocardial ischemia-reperfusion injury was established, and young/aged EVs were administered via intramyocardial injection to assess their effects on myocardial injury. Single-cell transcriptome sequencing was performed on heart tissues to analyze cellular subpopulations and energy metabolism pathways. Quantitative proteomics was employed to screen differentially expressed proteins between young and aged EVs, and the findings were validated in plasma EVs from elderly coronary heart disease patients. Co-immunoprecipitation was used to identify the interaction between PTX3 and thioredoxin 1. Rescue experiments with PTX3 overexpression and TXN1 silencing were conducted to verify the causal relationship.
Results
Aged EVs were efficiently internalized by cardiomyocytes and significantly aggravated myocardial injury, oxidative stress, mitochondrial dysfunction, and energy metabolism disorder in I/R rats. Single-cell transcriptomics revealed downregulated mitochondrial oxidative phosphorylation in cardiomyocytes. Proteomic analysis and clinical sample validation confirmed that PTX3 was significantly downregulated in aged rat EVs and plasma EVs from elderly patients. Mechanistically, PTX3 directly interacted with TXN1 to maintain redox balance and mitochondrial function. PTX3 overexpression ameliorated myocardial injury induced by aged EVs, whereas TXN1 silencing abolished the protective effects of PTX3.
Conclusion
Aged circulating EVs exacerbate myocardial I/R injury by downregulating PTX3 and disrupting its interaction with TXN1, leading to mitochondrial energy metabolism disorder and oxidative stress. The EV–PTX3–TXN1 axis serves as a novel mechanism and potential therapeutic target for age-related cardiovascular diseases.