Melatonin promotes the proliferation of dermal papilla cells in cashmere goats through the chi-miR-1388-3p/PDGFA axis

Background/objectives Melatonin (MT) promotes secondary hair follicle development and cashmere growth in cashmere goats; however, the underlying molecular mechanisms remain incompletely understood. This study investigated whether MT-associated changes in chi-miR-1388-3p are related to the regulation of cashmere goats dermal papilla cell (DPC) phenotypes through PDGFA , and examined the association of this regulatory axis with MAPK-related factors. Methods Candidate targets of chi-miR-1388-3p were predicted using the TargetScan database and previously generated transcriptomic data. The direct interaction between chi-miR-1388-3p and the PDGFA 3′ untranslated region (UTR) was evaluated using a dual-luciferase reporter assay. Lentiviral vectors were used to knock down or overexpress chi-miR-1388-3p in DPCs isolated from three independent cashmere goats donors. Each donor was treated as one biological replicate, and technical replicates were averaged before statistical analysis. Cell proliferation, cell-cycle distribution, and apoptosis were assessed using CCK-8 assays and flow cytometry. The expression of PDGFA , MAP3K1 , and FGF21 was examined by quantitative reverse-transcription PCR and Western blotting. MT treatment was performed for 48 h. Results Chi-miR-1388-3p directly targets the 3′ UTR of PDGFA . Its overexpression can inhibit the proliferation of DPC, increase G0/G1 phase arrest, and increase the apoptosis rate from 9.28% ± 0.17% to 17.61% ± 0.29% ( p < 0.01). Conversely, the inhibition of chi-miR-1388-3p promotes proliferation and reduces the apoptosis rate to 3.07% ± 0.11% ( p < 0.01). The overexpression of chi-miR-1388-3p can significantly reduce the expression levels of PDGFA, MAP3K1 and FGF21 ( p < 0.01), while the inhibitory effect has the opposite effect ( p < 0.01), while inhibition has the opposite effect. MT treatment can decrease the expression of chi-miR-1388-3p, accompanied by changes in DPC proliferation, apoptosis, and PDGFA expression. These results indicate that there is a correlation between the MT/chi-miR-1388-3p/ PDGFA axis and the expression of MAPK-related factors. Conclusion This study uncovers a novel mechanism by which MT regulates hair follicle growth and provides a foundation for future in vivo studies exploring miRNA-based strategies to enhance cashmere production.