Wen Xin, Liu Lu, Li Shanshan, Lin Pengfei, Chen Huatao, Zhou Dong, Tang Keqiong, Wang Aihua, Jin Yaping
Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, College of Veterinary Medicine, Northwest A&F University, Yangling, China.
Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Shaanxi, China.
Front Physiol. 2020 Sep 11;11:868. doi: 10.3389/fphys.2020.00868. eCollection 2020.
Corpus luteum (CL) is a transient endocrine tissue that produces progesterone for maintaining pregnancy in mammals. In addition, the regression of CL is necessary for the initiation of the estrous cycle. Extensive research has shown that the prostaglandin F2α (PGF2α) induces the regression of CL in ruminants. However, the mechanisms of endoplasmic reticulum (ER) stress and autophagy in the regression of goat CL induced by PGF2α are still unclear. In this study, ovaries of dioestrus goats and goats that were 3 months pregnant were collected to detect the location of the ER stress-related protein GRP78. The relationship between the different stages of the luteal phase of goat CL during the estrous cycle and changes in the expression of ER stress-related proteins and autophagy-related proteins was confirmed by western blot analysis. The results showed that both ER stress and autophagy were activated in the late luteal phase of the goat CL. To reveal the function of ER stress and autophagy in the CL regression process induced by PGF2α, we used 4-phenyl butyric acid (4-PBA) and chloroquine (CQ) for inhibiting ER stress and autophagy, respectively. Through the apoptotic rate detected by the flow cytometry and the expression of ER stress- and autophagy-related proteins detected by western blotting, we demonstrated that ER stress promoted goat luteal cell apoptosis and autophagy, and that apoptosis can be enhanced by the inhibition of autophagy. In addition, knockdown of EIF2S1, which blocked the PERK pathway activation, promoted apoptosis by reducing autophagy in goat luteal cells treated with PGF2α. In conclusion, our study indicates that ER stress promotes goat luteal cell apoptosis to regulate the regression of CL and activates autophagy to inhibit the goat luteal cell apoptosis via PERK signaling pathway.
黄体（CL）是一种短暂的内分泌组织，在哺乳动物中产生孕酮以维持妊娠。此外，黄体退化对于发情周期的启动是必要的。广泛的研究表明，前列腺素F2α（PGF2α）诱导反刍动物黄体退化。然而，内质网（ER）应激和自噬在PGF2α诱导的山羊黄体退化中的机制仍不清楚。在本研究中，收集处于间情期的山羊和妊娠3个月的山羊的卵巢，以检测内质网应激相关蛋白GRP78的定位。通过蛋白质免疫印迹分析证实了山羊发情周期中黄体期不同阶段与内质网应激相关蛋白和自噬相关蛋白表达变化之间的关系。结果表明，山羊黄体后期内质网应激和自噬均被激活。为了揭示内质网应激和自噬在PGF2α诱导的黄体退化过程中的作用，我们分别使用4-苯基丁酸（4-PBA）和氯喹（CQ）抑制内质网应激和自噬。通过流式细胞术检测凋亡率以及蛋白质免疫印迹检测内质网应激和自噬相关蛋白的表达，我们证明内质网应激促进山羊黄体细胞凋亡和自噬，并且抑制自噬可增强凋亡。此外，敲低EIF2S1可阻断PERK途径激活，通过减少PGF2α处理的山羊黄体细胞中的自噬来促进凋亡。总之，我们的研究表明内质网应激促进山羊黄体细胞凋亡以调节黄体退化，并通过PERK信号通路激活自噬以抑制山羊黄体细胞凋亡。
