Integrating miRNA, mRNA, and Targeted Metabolomics Analyses to Explore the Regulatory Mechanism of Cardiac Remodeling in Yili Horses.

Training not only enhances the athletic performance of horses but also improves cardiac structure and function, strengthens cardiovascular adaptability, and reduces the risk of cardiovascular diseases. However, the consequences of training on equine cardiac structure and function remain unclear. This study investigated the morphological, functional, genetic, and metabolic changes in the hearts of Yili horses divided into three groups: high athletic performance (agility group, AG), low athletic performance (ordinary group, OG), and untrained (untrained group, UN). The results showed remodeling of the cardiac structure and physiological adaptations in AG and OG compared to UN groups, with differences between AG and OG primarily in the left ventricle. To explore the molecular mechanisms underlying these phenotypic changes, transcriptomic and metabolomic analyses (particularly GO and KEGG pathway analyses) were performed to assess differences in gene expression and metabolite levels among the three groups. Our results show that miR-1842, miR-671, miR-106b and miR-18a were differentially expressed in the trained groups (AG group and OG group) compared with the control group that did not receive training. These regulatory factors would regulate PFKFB3 to affect the glycolytic activity mediated by HIF-1, there by promoting glycolysis and changing lactate level. This, in turn, would positively feedback to stabilize HIF-1, thus forming a closed loop for the reprogramming of myocardial energy metabolism. In the AG group, positive effects of cAMP signaling were noticeable. In conclusion, our findings offer new insights into physiological cardiac remodeling in Yili horses by highlighting genetic and metabolomic changes resulting from exercise training.