Effects of CircACAP2 on Apoptosis and Synthesis of β-casein and TG in Mammary Epithelial Cells of Dairy Goats (Capra hircus)
JIANG Yue1, ZHU Jun-Ru1, WU Shuang-Hu2, KOU Xiao-Yu3, AN Xiao-Peng1,*, SONG Yu-Xuan1,*
1 College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China;
2 Sanyuan County Animal Disease Prevention and Control Center, Sanyuan 713800, China;
3 Chunhua County Agricultural and Rural Bureau, Xianyang 711200, China
Abstract：The number and activity of mammary epithelial cells, lactation volume and milk composition are very important indicators in the breed selection of dairy goats (Capra hircus). The growth, development and lactation of the mammary gland is an extremely complex process. circACAP2 (circular ArfGAP with coiled-coil, ankyrin repeat and PH domains 2) can promote cardiomyocyte apoptosis while being highly expressed in breast cancer tissues, accelerating the progression of breast cancer. However, the regulatory effect of circACAP2 on goats mammary epithelial cells (GMECs) is not clear. In this study, circACAP2 overexpression and interference vector were constructed and transfected into GMECs, the results of double luciferase assay showed that circACAP2 could target binding with miR-21. qRT-PCR results showed that the interference with circACAP2 could significantly increase the expression of miR-21. The Cell proliferation test kit CCK8 (Cell Counting Kit-8) and 5-ethynyl-2'-deoxyuridine (EdU) experiments showed that circACAP2 inhibited the proliferation of GMECs, and the AnnexinV-FITC/PI apoptosis assay kit and flow cytometry detection showed that circACAP2 promoted the apoptosis of GMECs. The detection of ELISA kit showed that circACAP2 reduced the secretion of β-casein and triglyceride (TG). The ERK-Bax/Bcl-2 apoptosis signaling pathway and PI3K/mTOR/S6K lactating signaling pathway were selected for Western blot detections. The results showed that circACAP2 inhibited the expression of pERK1/2 and Bcl-2 and promoted the expression of Bax. Meanwhile, the phosphorylation level of PI3K, mTOR, and S6K decreased. The above results indicate that CircACAP2 might affect the apoptosis and proliferation of GMECs through the apoptosis signaling pathway ERK-Bax/Bcl-2, and affect the secretion of β-casein and TG in GMECs through the lactating signaling pathway PI3K/mTOR/S6K. This study provides basic data for further study of the lactation mechanism of Guanzhong dairy goats.
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