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 about animal welfare, with aggressive behavior recognized as a key determinant of both welfare and productivity. MicroRNAs (miRNAs), which are critical post-transcriptional regulators, have emerged as important modulators of animal behavior. This study investigated the molecular basis of aggression in pigs (Sus scrofa), focusing on miRNA-mediated regulation. Hypothalamic miRNA-sequencing of the most aggressive (n=4) and least aggressive (n=4) piglets identified nine differentially expressed miRNAs. Among these, miR-27a was significantly upregulated in aggressive individuals. Functional assays demonstrated that both porcine miR-27a and its human (Homo sapiens) ortholog has-miR-27a-3p, suppressed autophagy, apoptosis, and neuronal plasticity in primary porcine neurons and human SH-SY5Y neuroblastoma cells. To clarify the underlying mechanisms, mRNA-sequencing was performed on porcine neurons transfected with miR-27a mimics or negative controls, identifying 436 differentially expressed genes (84 upregulated and 352 downregulated). Gene Ontology(GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) analyses highlighted eight genes—CBL, PRKCA, SLC38A1, ZBTB16, AANAT, CYP1A1, SLC7A11, and NTRK2—associated with tryptophan metabolism, oxidative stress, and long-term synaptic depression. Bioinformatic analysis and dual-luciferase reporter assays confirmed that miR-27a directly targets the 3′-UTR of PRKCA, thereby suppressing of autophagy, apoptosis, and neuronal plasticity. In vivo, intrahypothalamic injection of mmu-miR-27a-3p in mice (Mus musculus) reduced motor function and social dominance, and placed the mice at a competitive disadvantage, while supressing neuronal autophagy, apoptosis and plasticity.