College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious, Diseases and Zoonoses, Yangzhou, 225009, Jiangsu, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious, Diseases and Zoonoses, Yangzhou, 225009, Jiangsu, China.
Toxicol Lett. 2020 May 1;323:1-9. doi: 10.1016/j.toxlet.2020.01.010. Epub 2020 Jan 23.
Zearalenone (ZEA) is a prevalent non-steroidal estrogenic mycotoxin produced mainly by Fusarium contamination. Our previous study showed that ZEA induces the autophagy of Sertoli cells (SCs). However, the underlying mechanisms are still unknown. Several studies have indicated that the increasing level of cytoplasmic Ca could induce autophagy through CaMKKβ and AMPK pathways. Thus in order to investigate the potential mechanism underlying ZEA-induced autophagy, the activity of calmodulin-dependent kinase kinase β(CaMKKβ)and AMP-activated protein kinase (AMPK) signaling pathway in ZEA-infected TM4 cells was studied. In the present study, ZEA activated the CaMKKβ and AMPK signaling pathways. The AMPK inhibitor and activator significantly inhibited and stimulated the effect of ZEA on AMPK, the transformation from LC3I to LC3II, and the distribution of LC3 dots. In addition, cytosolic calcium (Ca) was increased gradually with the concentration of ZEA. After treatment of ZEA-infected cells with 1, 2-bis (2-aminophenoxy) ethane-N, N, N', N'- tetraacetic acid- tetraac etoxymethyl ester (BAPTA-AM) and 2-aminoethyl diphenylborinate (2-APB), the intracellular concentration of Ca reduced significantly. Also, the activities of CaMKKβ and AMPK and subsequent autophagy decreased. Moreover, the antioxidant NAC significantly decreased activities of AMPK and autophagy -related protein. Therefore, it can be speculated that ROS- mediated ER-stress induced by ZEA activates AMPK via Ca-CaMKKβ leading to autophagy in TM4 cells.
玉米赤霉烯酮（ZEA）是一种普遍存在的非甾体类雌激素真菌毒素，主要由镰刀菌污染产生。我们之前的研究表明，ZEA 可诱导支持细胞（SCs）自噬。然而，其潜在机制尚不清楚。有几项研究表明，细胞质 Ca 水平的升高可以通过 CaMKKβ 和 AMPK 途径诱导自噬。因此，为了研究 ZEA 诱导自噬的潜在机制，本研究研究了 ZEA 感染的 TM4 细胞中钙调蛋白依赖性激酶激酶β（CaMKKβ）和 AMP 激活蛋白激酶（AMPK）信号通路的活性。在本研究中，ZEA 激活了 CaMKKβ 和 AMPK 信号通路。AMPK 抑制剂和激动剂显著抑制和刺激了 ZEA 对 AMPK、LC3I 向 LC3II 的转化以及 LC3 斑点的分布的作用。此外，细胞浆 Ca（Ca）随着 ZEA 浓度的增加而逐渐增加。用 1,2-双（2-氨基苯氧基）乙烷-N，N，N'，N'-四乙酸四乙酸甲酯（BAPTA-AM）和 2-氨基乙基二苯硼酸盐（2-APB）处理 ZEA 感染的细胞后，细胞内 Ca 浓度显著降低。同时，CaMKKβ 和 AMPK 的活性以及随后的自噬也降低。此外，抗氧化剂 NAC 显著降低了 AMPK 和自噬相关蛋白的活性。因此，可以推测 ZEA 介导的 ROS-内质网应激通过 Ca-CaMKKβ 激活 AMPK，导致 TM4 细胞自噬。
