and Regulate Heat Stress Response in Hu Sheep Through Lipid Metabolism via m6A Modification.

In an established hepatocyte lipid deposition heat stress model, the expression levels of and were significantly upregulated ( < 0.05), indicating that and play important roles in the process of lipid deposition heat stress in hepatocytes. Transcriptome and metabolome analyses showed that lipid deposition heat stress had significant effects on the linoleic acid, linolenic acid, glycerophospholipid, and arachidonic acid metabolic pathways in hepatocytes. After knockdown, the m6A methylation level decreased, but the difference was not significant ( > 0.05), the and expression levels increased, and the , , and expression levels decreased significantly. After overexpression, the m6A methylation level increased significantly and the expression levels of , , , , , , and decreased significantly, indicating that the overexpression of reduced the expression of heat shock genes by inhibiting the lipid-deposition-related gene expression in an m6A-dependent manner. The m6A methylation level increased significantly after knockdown, while , , , , and Accα expression levels were significantly reduced. Following overexpression, the m6A methylation level and , , and expression levels significantly decreased, while the and expression levels significantly increased. This indicates that the overexpression of promoted the expression of lipid-deposition-related genes in an m6A-dependent manner to reduce the expression of heat shock genes. Transcriptome and metabolome sequencing screened a large number of differential genes and metabolites, and a KEGG enrichment analysis showed that m6A methylation mainly regulated heat stress by affecting the TNF, cAMP, MAPK, lipolysis, and synthesis pathways in hepatocytes. In the lipid deposition heat stress model of preadipocytes, the regulation of gene expression was similar to that in hepatocytes.