Combined Analysis of the Transcriptome and Metabolome at Different Tissue Glycogen Levels in Yili Horses

This study aimed to investigate the relationship between genes and metabolites involved in glycogen metabolism across different tissues of Yili mares using joint transcriptomic and metabolomic analyses. Glycogen content was measured in various tissues (pincer, trapezius, latissimus dorsi, gluteus medius, semitendinosus, external abdominal obliques, liver, and heart) from seven Yili mares. The liver, as the visceral tissue with the highest glycogen content, and the gluteus medius, as the muscle with the highest glycogen content, were selected for transcriptomic sequencing and metabolomic analysis. KEGG pathway analysis of differentially expressed genes and metabolites in the liver and the gluteus medius revealed several key pathways associated with glycogen metabolism, including pentose and glucuronic acid interconversion, glycolysis/gluconeogenesis, the TCA cycle, fructose and mannose metabolism, and the pentose phosphate pathway. The gluteus medius tissue exhibited differential expression of 1485 metabolites and 7366 genes compared to the liver, with correlation coefficients between some genes and metabolites in the aforementioned pathways exceeding 0.8. This study highlights the regulatory differences in glycogen synthesis between liver and muscle tissues in Yili horses from multiple perspectives. Notably, genes such as ACO1, ACLY, PCK2, and FBP1, along with metabolites like leucine, tyrosine, and valine, play significant roles in regulating glycogen synthesis in the liver. It is hypothesized that these genes and metabolites contribute to the observed differences in energy metabolism between liver and muscle tissues in Yili horses; however, further in vivo and in vitro experiments are needed to validate this hypothesis.