Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow 226031, U.P., India; Academy of Scientific and Innovative Research (AcSIR), CSIR-CDRI Campus, Lucknow 226031, U.P., India.
Division of Endocrinology, CSIR-Central Drug Research Institute, Lucknow 226031, U.P., India.
Free Radic Biol Med. 2018 Dec;129:582-599. doi: 10.1016/j.freeradbiomed.2018.10.427. Epub 2018 Oct 19.
Hh/Gli1 cascade as well as Gsk3β-Gli1 crosstalk play crucial role in estrogen-dependent progression of endometrial hyperplasia (EH). However, the underlying mechanisms involved in progression of disease still remain unclear. In the present study, we explored the role of Hh signaling in protection of endometrial hyperplasial cells against oxidative stress and the underlying mechanism involved therein. EH cells were found to be more resistant towards HO-induced oxidative stress (IC: ~ 3×) as compared with normal endometrial cells. Estrogen (E2) pre-treatment followed by cytotoxic dose of HO almost rescued the EH cells from apoptosis and caused the increased expression of downstream Shh signaling molecules i.e., Smo, Ptch and Gli1. Whereas pretreatment with cyclopamine was not able to curtail HO-induced effects indicating that estrogen protects these cells via activation of Shh pathway. Further, HO-induced ROS and lipid peroxidation alongwith decreased activities of antioxidant enzymes glutathione peroxidase and superoxide dismutase were found to be reversed in EH cells pre-exposed to E2 or rShh. The rShh suppressed HO-induced cell death and caused attenuation of mitochondrial apoptotic mediators and prevented disruption in mitochondrial morphology and mitochondrial membrane potential in EH cells. The functional blockage of signaling by Shh siRNA or Gli1siRNA led to significantly increased expression of mitochondrial fission protein dynamin-like GTPase (Drp1). The HO-treated EH cells showed diminished Gli1 and increased Drp1 expression, concurrent with reduced p-Drp1-(serine637). Whereas rShh pre-treated EH cells presented normal mitochondrial dynamics with dense, long networks of mitochondria alongwith nuclear accumulation of Gli1 and the decreased expression of Drp1. Overall, our results implicated that Shh signaling modulates antioxidant defense system and stabilizes mitochondrial dynamics by suppressing Drp1 protein which maintains survival of EH cells against oxidative stress.
Hh/Gli1 级联以及 Gsk3β-Gli1 串扰在雌激素依赖性子宫内膜增生症 (EH) 的进展中发挥关键作用。然而，疾病进展中涉及的潜在机制仍不清楚。在本研究中，我们探讨了 Hh 信号在保护子宫内膜增生细胞免受氧化应激中的作用及其潜在机制。与正常子宫内膜细胞相比，EH 细胞对 HO 诱导的氧化应激具有更强的抗性（IC：~3×）。雌激素 (E2) 预处理后再用细胞毒性剂量的 HO，几乎可以使 EH 细胞免于凋亡，并导致下游 Shh 信号分子 Smo、Ptch 和 Gli1 的表达增加。然而，用环巴胺预处理不能抑制 HO 诱导的作用，表明雌激素通过激活 Shh 通路来保护这些细胞。此外，HO 诱导的 ROS 和脂质过氧化以及抗氧化酶谷胱甘肽过氧化物酶和超氧化物歧化酶活性的降低在预先暴露于 E2 或 rShh 的 EH 细胞中得到逆转。rShh 抑制 HO 诱导的细胞死亡，并减弱线粒体凋亡介质的作用，防止 EH 细胞中线粒体形态和线粒体膜电位的破坏。通过 Shh siRNA 或 Gli1siRNA 阻断信号转导会导致线粒体分裂蛋白 dynamin-like GTPase (Drp1) 的表达显著增加。HO 处理的 EH 细胞显示出Gli1 减少和 Drp1 增加，同时 p-Drp1-(丝氨酸 637)减少。相反，预先用 rShh 处理的 EH 细胞表现出正常的线粒体动力学，具有密集的、长的线粒体网络，以及Gli1 的核积累和 Drp1 的表达减少。总的来说，我们的结果表明，Shh 信号通过抑制 Drp1 蛋白来调节抗氧化防御系统并稳定线粒体动力学，从而维持 EH 细胞对氧化应激的存活。
