Department of Animal Science, Chungbuk National University, Cheongju, South Korea 28644, Korea.
College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China.
Zool Res. 2023 Sep 18;44(5):848-859. doi: 10.24272/j.issn.2095-8137.2023.080.
Activating transcription factor 6 (ATF6), one of the three sensor proteins in the endoplasmic reticulum (ER), is an important regulator of ER stress-induced apoptosis. ATF6 resides in the ER and, upon activation, is translocated to the Golgi apparatus, where it is cleaved by site-1 protease (S1P) to generate an amino-terminal cytoplasmic fragment. Although recent studies have made progress in elucidating the regulatory mechanisms of ATF6, its function during early porcine embryonic development under high-temperature (HT) stress remains unclear. In this study, zygotes were divided into four groups: control, HT, HT+ATF6 knockdown, and HT+PF (S1P inhibitor). Results showed that HT exposure induced ER stress, which increased ATF6 protein expression and led to a decrease in the blastocyst rate. Next, ATF6 expression was knocked down in HT embryos under microinjection of double-stranded RNA (dsRNA). Results revealed that ATF6 knockdown (ATF6-KD) attenuated the increased expression of CHOP, an ER stress marker, and Ca release induced by HT. In addition, ATF6-KD alleviated homeostasis dysregulation among organelles caused by HT-induced ER stress, and further reduced Golgi apparatus and mitochondrial dysfunction in HT embryos. AIFM2 is an important downstream effector of ATF6. Results showed that ATF6-KD reduced the occurrence of AIFM2-mediated embryonic apoptosis at HT. Taken together, our findings suggest that ATF6 is a crucial mediator of apoptosis during early porcine embryonic development, resulting from HT-induced ER stress and disruption of organelle homeostasis.
激活转录因子 6（ATF6）是内质网（ER）中的三种传感器蛋白之一，是 ER 应激诱导细胞凋亡的重要调节因子。ATF6 位于 ER 中，激活后被转运到高尔基器，在那里它被位点 1 蛋白酶（S1P）切割，生成一个氨基末端胞质片段。尽管最近的研究在阐明 ATF6 的调节机制方面取得了进展，但它在高温（HT）应激下早期猪胚胎发育中的功能仍不清楚。在这项研究中，将受精卵分为四组：对照组、HT 组、HT+ATF6 敲低组和 HT+PF（S1P 抑制剂）组。结果表明，HT 暴露诱导 ER 应激，增加 ATF6 蛋白表达，导致囊胚率降低。接下来，通过双链 RNA（dsRNA）的显微注射在 HT 胚胎中敲低 ATF6 的表达。结果表明，ATF6 敲低（ATF6-KD）减弱了 HT 诱导的 ER 应激增加的 CHOP（ER 应激标志物）的表达和 Ca2+释放。此外，ATF6-KD 缓解了 HT 诱导的 ER 应激引起的细胞器间稳态失调，并进一步减少了 HT 胚胎中的高尔基体和线粒体功能障碍。AIFM2 是 ATF6 的一个重要下游效应物。结果表明，ATF6-KD 减少了 HT 诱导的胚胎凋亡中 AIFM2 介导的凋亡的发生。总之，我们的研究结果表明，ATF6 是 HT 诱导的 ER 应激和细胞器稳态破坏导致早期猪胚胎发育中细胞凋亡的关键介质。
