CIDEA promotes lipid deposition through focal adhesion pathway in goat intramuscular preadipocytes

Intramuscular fat (IMF) content determines the quality of goat meat, and is strongly associated with the number and volume of adipocytes, which is regulated by the comprehensive effect of proliferation and adipogenesis of intramuscular preadipocytes. Cell death-inducing DNA fragmentation factor alpha (DFFA)-like effector (CIDE) proteins has emerged as lipid droplets (LDs)-related proteins, implying the important roles in lipid homeostasis. However, the mechanism through which CIDEA , one member of CIDE family, regulates intramuscular fat deposition remains unclear. To address this, we dysregulated CIDEA in intramuscular preadipocytes and resolved the effect and mechanism of CIEDA in adipogenesis through RT-PCR, Western blot, triglyceride and LDs determinations, CCK-8 and RNA-seq. It was found that CIDEA increased LDs and triglyceride contents and inhibited cell proliferation. Lipid metabolism-related genes PPARγ , C/EBPα , SREBP1c , PLIN1 , TIP47 , ADFP , DGAT1 , ACC , FASN , ACSL1 , FABP3 were upregulated after CIDEA overexpression. Moreover, lipolysis and β oxidation genes HSL , ACOX1 , CPT1B and proliferation marker genes CDK1 were upregulated. Differentially expressed genes in RNA-seq results were selected and enriched in the apelin and focal adhesion signaling pathways. Specifically, CIDEA regulated the activation of focal adhesion kinase and AKT signaling proteins, but not p38 signaling. To this end, we did the rescue assay and found that suppressing focal adhesion kinase signaling pathway with PF573228 reversed the lipid droplets and triglyceride contents increase induced by CIDEA overexpressing and further decreased their contents in CIDEA interfering group. In summary, this study reveals that CIDEA promotes lipid deposition in intramuscular preadipocytes through the focal adhesion pathway and inhibiting the cell proliferation. These works clarify the functional role and downstream signaling pathway of CIDEA in intramuscular fat deposition and provide theoretical support for improving meat quality through manipulating phenotype-related key genes.