Integrating lipidomics and transcriptomics to reveal the heterogeneity of sheep adipose tissues

Adipose tissue is a heterogeneous organ with energy storage, thermogenesis, and endocrine functions. The study aims to identify the key lipid molecules and genes that affect the heterogeneity of adipose tissue in different parts of sheep. The differences in lipid molecules and fatty acid contents in perirenal fat (PF), omental fat (OF), back subcutaneous fat (SF), and tail fat (TF) of Hu sheep were analyzed using widely targeted lipidomic and gas chromatography techniques. Subsequently, the key genes that affect the heterogeneity of adipose tissue were explored in combination with transcriptome data. The results showed that subcutaneous fat (SAT, SF, and TF) had lower levels of C18:0, C16:0, C18:1n9t, and total fatty acids but higher levels of C18:0anteiso, C18:1n9c, triglycerides, and glycerophospholipids compared to visceral fat (VAT, PF, and OF). A total of 690 differential lipid molecules (DLMs) and 3,048 differentially expressed genes (DEGs) were detected among 4 fat tissues by lipidomics and transcriptomics, respectively. Both DLMs and DEGs were significantly enriched in the glycerolipid metabolism and insulin resistance pathways. The weighted gene co-expression network analysis identified that PPP1R3C, SRD5A1, and GRHPR were associated with metabolic processes. Combined analyses of lipidomic and transcriptomic found that LPL, G6PC3, SLC2A1, GPAT3, and GFPT1 were associated with lipid metabolism and metabolic disease. This study identifies key genes and lipid molecules that affect the heterogeneity of adipose tissue, providing new molecular mechanisms for understanding the heterogeneity of adipose tissue and its role in energy balance and metabolic regulation.