gga-let-7c-3p Inhibits Chicken Abdominal Adipogenesis by Regulating PPARD Gene

MicroRNAs (miRNAs) have been increasingly involved in mammalian lipid metabolism. However, their regulatory roles and molecular mechanisms in abdominal fat deposition in chicken remain largely unexplored. In this study, based on the previous miRNA transcriptome data during chicken abdominal preadipocytes' adipogenic differentiation, we explored the biological functions and regulatory mechanisms of a differentially expressed miRNA, gga-let-7c-3p, in adipogenesis. Gain- and loss-of-function assays elucidated that gga-let-7c-3p significantly decreased viability, proliferation, cell cycle progression, intracellular lipid droplet accumulation and triglyceride content, as well as the mRNA expression of proliferation- and lipid metabolism-related genes in chicken abdominal preadipocytes. Dual-luciferase reporter assay confirmed that gga-let-7c-3p could directly interact with the 3'UTR of the transcription factor-peroxisome proliferator activated the receptor delta (<i>PPARD</i>) gene and thus inhibited its post-transcriptional expression. The <i>PPARD</i> gene significantly decreased viability, proliferation, and cell cycle progression, while it increased intracellular lipid droplet accumulation and triglyceride content of chicken abdominal preadipocytes, paralleling with the mRNA expression of proliferation- and lipid metabolism-related genes. Collectively, gga-let-7c-3p could inhibit the proliferation and adipogenic differentiation of chicken abdominal preadipocytes, at least by targeting the <i>PPARD</i> gene. These findings reveal the regulatory mechanisms of the gga-let-7c-3p/<i>PPARD</i> axis in chicken abdominal adipogenesis, and could provide potential molecular markers for lean line broiler breeding.