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

## TL;DR

This study explores how genes and metabolites contribute to glycogen metabolism in different tissues of Yili horses, focusing on liver and muscle tissues.

## Contribution

The study provides a multi-omics analysis of glycogen metabolism in Yili horses, revealing key genes and metabolites involved in tissue-specific regulation.

## Key findings

- Differentially expressed genes in liver and muscle tissues are primarily linked to glycolysis and fructose/mannose metabolism.
- Key genes like ACO1, ACLY, PCK2, and FBP1, along with metabolites like leucine and tyrosine, are associated with glycogen synthesis in the liver.
- The study identifies regulatory differences in glycogen metabolism between liver and muscle tissues in Yili horses.

## Abstract

This study systematically analyzed the glycogen content across various tissues in Yili horses, conducting transcriptomic and broadly targeted metabolomics investigations on the visceral (liver) and muscle (gluteus medius) tissues, which exhibit the highest glycogen concentrations. A total of 1485 metabolites and 7366 mRNAs were identified with differential expression. Notably, these differentially expressed genes are predominantly involved in glycolysis and the metabolism of fructose and mannose. Through a multi−omics joint analysis, the mechanisms underlying glycogen synthesis and accumulation in different tissues of Yili horses were explored at a deeper and broader level, providing a theoretical foundation for elucidating the genetic mechanisms of glycogen metabolism in this breed.

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.