[miR-454-3p suppresses the proliferation of abdominal preadipocytes in broilers]

To elucidate the role and molecular mechanism of miR-454-3p in the development of abdominal fat in broilers, this study analyzed its expression profiles across different tissues and abdominal adipocytes, and evaluated its regulatory effects on proliferation and differentiation of adipocytes. The results showed that miR-454-3p was highly expressed in the heart, breast muscle, brain, and abdominal adipose tissue, but exhibited relatively low expression in the lung, liver, small intestine, and kidney. During cell proliferation, miR-454-3p expression displayed a dynamic pattern characterized by an initial decrease followed by an increase, whereas it gradually declined during adipogenic differentiation. Functional analyses demonstrated that overexpression of miR-454-3p significantly inhibited cell proliferation and lipid droplet accumulation, accompanied by downregulation of proliferation- and adipogenesis-related genes, including CCND1, CDK2, PCNA, C/EBPβ, PPARγ, and PLIN1. Whereas inhibition of miR-454-3p exerted the opposite effects (P0.05). Transcriptomic analysis revealed that genes upregulated by miR-454-3p were enriched in biological processes related to non-adipogenic lineage development and negative regulation of cell proliferation, while downregulated genes were primarily involved in lipid metabolism, adipogenesis, and cell growth-associated pathways. Further validation using bioinformatic prediction, immunoblotting, and dual-luciferase reporter assays confirmed that the transcription factors KLF7 and PPARγ are direct targets of miR-454-3p, with conserved binding sites across vertebrates. Rescue experiments further demonstrated that overexpression of KLF7 and PPARγ significantly reversed the inhibitory effects of miR-454-3p on preadipocyte proliferation and differentiation (P0.05). In summary, miR-454-3p coordinately suppresses preadipocyte proliferation and differentiation by directly targeting KLF7 and PPARγ, providing a theoretical basis for understanding miRNA-mediated post-transcriptional regulation in adipose tissue development.