Activation of Focal Adhesion Pathway by CIDEA as Key Regulatory Axis in Lipid Deposition in Goat Intramuscular Precursor Adipocytes.

Intramuscular fat (IMF) content determines the quality of goat meat and is regulated by the comprehensive effect of the proliferation and adipogenesis of intramuscular preadipocytes. Our previous RNA-seq data revealed that cell death-inducing DNA fragmentation factor alpha (DFFA)-like effector (CIDE) A was upregulated during the development of intramuscular fat in the longissimus dorsi muscle tissue, implying an important role in lipid homeostasis. However, the mechanism by which CIDEA, a member of the CIDE family, regulates intramuscular fat deposition in goat muscle is unknown, so we explored the function and underlying mechanism of CIDEA in goat intramuscular preadipocytes. To address this, we altered CIDEA in intramuscular preadipocytes and resolved the effect and mechanism of CIDEA in adipogenesis through RT-PCR, Western blot, triglyceride and LD determinations, CCK-8, and RNA-seq. It was found that CIDEA increased lipid droplets (LDs) and triglyceride contents and inhibited cell proliferation. Meanwhile, the lipid metabolism-related genes PPARγ, C/EBPα, SREBP1c, PLIN1, TIP47, ADFP, DGAT1, ACC, FASN, ACSL1, and FABP3 were upregulated, while the lipolysis and β-oxidation genes HSL, ACOX1, and CPT1B, as well as the proliferation marker gene CDK1, were all downregulated upon CIDEA overexpression. Differentially expressed genes in CIDEA dysregulation groups through RNA-seq were selected and were enriched in the apelin and focal adhesion signaling pathways. Specifically, the Western blot and rescue assays found that focal adhesion, but not apelin, was the key signaling pathway in CIDEA regulating lipid deposition in goat intramuscular preadipocytes. In summary, this study reveals that CIDEA promotes lipid deposition in intramuscular preadipocytes through the focal adhesion pathway and inhibits cell proliferation. This work clarifies the functional role and downstream signaling pathway of CIDEA in intramuscular fat deposition and provides theoretical support for improving meat quality by targeting key phenotype-related genes.