RESUMO
MicroRNAs are small, non-coding RNAs that regulate the expression of target genes. Previous research has demonstrated that microRNA-200a regulates cell apoptosis, tumor progression, and autoimmune disease. Preliminary studies found that microRNA-200a was differently expressed in the skin of Cashmere goats of various coat colors. However, the role of microRNA-200a in skin pigmentation remained poorly understood. In the current study, we investigated the effect of microRNA-200a on pigmentation in Cashmere goats. The expression of target genes was detected by real-time quantitative PCR, western blot, and immunohistochemistry staining both in vivo and in vitro. Luciferase reporter assays were used to demonstrate the relationship between microRNA-200a and its target genes Wnt family member 5A and frizzled class receptor 4 (WNT5A and FZD4) in HEK293T cells. BALB/c mice were injected with antagomiR-200a to detect melanin content and the expression of microRNA-200a and its target genes. The results demonstrated that the expression of microRNA-200a was significantly higher in brown tissue. Luciferase reporter assays confirmed that microRNA-200a targeted WNT5A and FZD4. The expression of WNT5A and FZD4 in the skin of brown Cashmere goats was significantly lower than that in white Cashmere goats by the detection of mRNA and protein levels. Overexpression/inhibition of microRNA-200a in keratinocytes decreased/increased the mRNA and protein expression of WNT5A and FZD4, respectively. In addition, the expression of WNT5A and FZD4 increased in the skin of BALB/c mice injected with antagomiR-200a, but the melanin content decreased. In summary, this study indicated that microRNA-200a regulates skin pigmentation by targeting WNT5A and FZD4 in Cashmere goats.