miR-143 Targeting CUX1 to Regulate Proliferation of Dermal Papilla Cells in Hu Sheep

Wool curvature is the determining factor for lambskin quality of Hu lambs. However, the molecular mechanism of wool curvature formation is not yet known. miRNA has been proved to play an important role in hair follicle development, and we have discovered a differentially expressed miRNA, miR-143, in hair follicles of different curl levels. In this study, we first examined the effects of miR-143 on the proliferation and cell cycle of dermal papilla cells using CCK8, EdU and flow cytometry and showed that miR-143 inhibited the proliferation of dermal papilla cells and slowed down the cell cycle. Bioinformatics analysis was performed to predict the target genes KRT71 and CUX1 of miR-143, and both two genes were expressed at significantly higher levels in small waves than in straight lambskin wool (p < 0.05) as detected by qPCR and Western blot (WB). Then, the target relationships between miR-143 and KRT71 and CUX1 were verified through the dual-luciferase assay in 293T cells. Finally, after overexpression and suppression of miR-143 in dermal papilla cells, the expression trend of CUX1 was contrary to that of miR-143. Meanwhile, KRT71 was not detected because KRT71 was not expressed in dermal papilla cells. Therefore, we speculated that miR-143 can target CUX1 to inhibit the proliferation of dermal papilla cells, while miR-143 can target KRT71 to regulate the growth and development of hair follicles, so as to affect the development of hair follicles and ultimately affect the formation of wool curvature.