Integrated Transcriptomic and Proteomic Analysis Associated with Knockdown and Overexpression Studies Revealed ECHDC1 as a Regulator of Intramuscular Fat Deposition in Cattle

Intramuscular fat (IMF) content is a critical determinant of beef quality and is regulated by various factors. However, the molecular mechanisms underlying IMF deposition in cattle remain poorly understood, particularly with regard to multi-omics integrated analyses. In this study, an integrative analysis of transcriptomic and proteomic profiles was performed on intramuscular fat tissue of Jiaxian Red cattle with different marbling grades to identify key genes and pathways involved in intramuscular fat deposition in beef cattle. Integrated analysis showed that 4532 genes were co-expressed at both mRNA and protein level, among which 21 genes exhibited significant differential expression at mRNA and protein level. These genes showed significant enrichment in lipid biosynthesis and metabolic processes. ECHDC1 was selected for in-depth functional studies on bovine intramuscular preadipocyte adipogenesis as a candidate gene via RNA interference and overexpression techniques. The results indicated that knockdown of ECHDC1 inhibited the adipogenesis of bovine intramuscular preadipocytes and significantly upregulated the expression of HSL. Conversely, overexpression of ECHDC1 promoted the adipogenesis of bovine intramuscular preadipocytes, decreased the expression of HSL and increased the expression of FABP4. In summary, these results suggested that ECHDC1 promoted intramuscular fat deposition by attenuating lipolysis rate by downregulating the expression of the lipolytic gene HSL, providing a potential molecular target for enhancing IMF content in beef cattle.