Molecular mechanisms of the hypothalamus miR-27a/PRKCA pathway in regulating neuronal function and aggression-related behavior

The intensification of livestock production has heightened public concern over animal welfare, with aggressive behavior recognized as a key determinant of both welfare and productivity. MicroRNAs (miRNAs), critical post-transcriptional regulators, have emerged as important modulators of animal behavior. This study investigates the molecular basis of aggression in pigs, focusing on miRNA-mediated regulation. Using miRNA-seq of the hypothalamus from the most aggressive (n = 4) and least aggressive (n = 4) piglets, nine differentially expressed miRNAs were identified. Among them, miR-27a was significantly upregulated in aggressive individuals. Functional assays demonstrated that both porcine miR-27a and its human ortholog hsa-miR-27a-3p suppress autophagy, apoptosis, and neuronal plasticity in primary porcine neurons and human SH-SY5Y neuroblastoma cells. To clarify the underlying mechanisms, mRNA-seq was performed on porcine neurons transfected with miR-27a mimics or negative controls, identifying 436 differentially expressed genes (84 upregulated, 352 downregulated). Enrichment analyses (GO, KEGG, PPI) highlighted eight genes—CBL, PRKCA, SLC38A1, ZBTB16, AANAT, CYP1A1, SLC7A11, and NTRK2—linked to pathways including tryptophan metabolism, oxidative stress, and long-term synaptic inhibition. Bioinformatic and dual-luciferase reporter assays confirmed that miR-27a directly targets the 3′-UTR of PRKCA, mediating suppression of autophagy, apoptosis, and plasticity. In vivo, intrahypothalamic injection of mmu-miR-27a-3p in mice reduced motor function, diminished social dominance, and conferred a competitive disadvantage, while inhibiting autophagy, apoptosis and plasticity of mouse neurons.