Endurance exercise upregulates mtp expression in aged Drosophila to ameliorate age-related diastolic dysfunction and extend lifespan.

Diastolic dysfunction is a major cardiac dysfunction, and an important predisposing factor is age. Although exercise training is often used for the prevention and treatment of cardiovascular disease nowadays, little is currently known about whether exercise interventions associated with the slowing of cardiac aging are related to mtp-related pathways. In the present study, the UAS/Tub-Gal4 system was used to knockdown whole-body mtp expression levels in Drosophila, which underwent 2 weeks of endurance training. By conducting different assays and quantifying different indicators, we sought to investigate the relationship between mtp, exercise, and age-related diastolic dysfunction. We found that (1) Drosophila in the mtpRNAi youth group exhibited age-related diastolic dysfunction and had a significantly shorter mean lifespan. (2) Endurance exercise could improve diastolic dysfunction and prolong lifespan in aged Drosophila. (3) Endurance exercise could increase the expression levels of apolpp and Acox3, and decrease the levels of TC, LDL-C, and TG in the aged group. In summary, aging causes age-associated diastolic dysfunction in Drosophila, and systemic knockdown of mtp causes premature age-associated diastolic dysfunction in young Drosophila. Besides, endurance exercise improves age-related diastolic dysfunction and prolongs lifespan.

Regular Exercise Modulates the dfoxo/dsrebp Pathway to Alleviate High-Fat-Diet-Induced Obesity and Cardiac Dysfunction in Drosophila.

Obesity is a prevalent metabolic disorder associated with various diseases, including cardiovascular conditions. While exercise is recognized as an effective approach for preventing and treating obesity, its underlying molecular mechanisms remain unclear. This study aimed to explore the impact of regular exercise on high-fat-diet-induced obesity and cardiac dysfunction in Drosophila, shedding light on its molecular mechanisms by identifying its regulation of the dfoxo and dsrebp signaling pathways. Our findings demonstrated that a high-fat diet leads to weight gain, fat accumulation, reduced climbing performance, and elevated triglyceride levels in Drosophila. Additionally, cardiac microfilaments in these flies exhibited irregularities, breakages, and shortening. M-mode analysis revealed that high-fat-diet-fed Drosophila displayed increased heart rates, shortened cardiac cycles, decreased systolic intervals, heightened arrhythmia indices, reduced diastolic diameters, and diminished fractional shortening. Remarkably, regular exercise effectively ameliorated these adverse outcomes. Further analysis showed that regular exercise reduced fat synthesis, promoted lipolysis, and mitigated high-fat-diet-induced cardiac dysfunction in Drosophila. These results suggest that regular exercise may mitigate high-fat-diet-induced obesity and cardiac dysfunction in Drosophila by regulating the dfoxo and dsrebp signaling pathways, offering valuable insights into the mechanisms underlying the beneficial effects of exercise on obesity and cardiac dysfunction induced by a high-fat diet.

Exercise Training Upregulates Cardiac mtp Expression in Drosophila melanogaster with HFD to Improve Cardiac Dysfunction and Abnormal Lipid Metabolism.

Current evidence suggests that the heart plays an important role in regulating systemic lipid homeostasis, and high-fat diet (HFD)-induced obesity is a major cause of cardiovascular disease, although little is known about the specific mechanisms involved. Exercise training can reportedly improve abnormal lipid metabolism and cardiac dysfunction induced by high-fat diets; however, the molecular mechanisms are not yet understood. In the present study, to explore the relationship between exercise training and cardiac mtp in HFD flies and potential mechanisms by which exercise training affects HFD flies, Drosophila was selected as a model organism, and the GAL4/UAS system was used to specifically knock down the target gene. Experiments revealed that HFD-fed Drosophila exhibited changes in body weight, increased triglycerides (TG) and dysregulated cardiac contractility, consistent with observations in mammals. Interestingly, inhibition of cardiac mtp expression reduced HFD-induced cardiac damage and mitigated the increase in triglycerides. Further studies showed that in HFD +w1118, HFD + Hand > w1118, and HFD+ Hand > mtpRNAi, cardiac mtp expression downregulation induced by HFD was treated by exercise training and mitochondrial ß-oxidation capacity in cardiomyocytes was reversed. Overall, knocking down mtp in the heart prevented an increase in systemic TG levels and protected cardiac contractility from damage caused by HFD, similar to the findings observed after exercise training. Moreover, exercise training upregulated the decrease in cardiac mtp expression induced by HFD. Increased Had1 and Acox3 expression were observed, consistent with changes in cardiac mtp expression.