Vincent Center for Reproductive Biology, Department of Obstetrics, Gynecology, and Reproductive Biology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
Endocrinology. 2012 Jan;153(1):404-16. doi: 10.1210/en.2011-1191. Epub 2011 Nov 29.
Tumors develop with dysregulated activation of mammalian target of rapamycin (mTOR), the kinase activity of which is kept in an inactive state by a tumor suppressor dimer containing tuberous sclerosis 1 (TSC1) and TSC2. We examined whether conditional deletion of TSC1 by a knock-in allele of the anti-Müllerian hormone type 2 receptor (Amhr2) driving Cre expression and subsequent activation of mTOR in granulosa cells and in oviductal and uterine stromal cells affects fertility in female mice. Increased phosphorylation of ribosomal protein S6, a downstream target of activated mTOR, was observed in all AMHR2-expressing tissues examined, indicating loss of TSC1 activity. TSC1 deletion in granulosa cells led to the detection of significantly fewer primordial follicles in mutant mice at 12 wk, suggesting premature ovarian insufficiency, which might be related to the significantly increased time mutant mice spent in estrus. Although the number of good-quality ovulated oocytes was not significantly different compared with controls, there was a significantly higher number of degenerated oocytes after normal and superovulation, suggesting compromised oocyte quality, as well. Natural mating also showed severalfold higher numbers of degenerate bodies in the mutants that collected in bilateral swellings resembling hydrosalpinges that formed in all mice examined because of occlusion of the proximal oviduct. Attempts to transfer control embryos into mutant uteri also failed, indicating that implantation was compromised. Endometrial epithelial cells continued to proliferate, and quantitative RT-PCR showed that mucin 1 expression persisted during the window of implantation in mutant uteri, without any changes in progesterone receptor mRNA expression, suggesting a mechanism that does not involve disrupted estradiol-regulated progesterone receptor expression. Homozygous deletion of TSC1 in reproductive tract somatic tissues of mice rendered females completely infertile, which is likely due to these pleiotropic effects on follicle recruitment, oviductal development, and blastocyst implantation.
肿瘤的发生与哺乳动物雷帕霉素靶蛋白（mTOR）的失调激活有关，mTOR 的激酶活性被含有结节性硬化症 1（TSC1）和 TSC2 的肿瘤抑制子二聚体保持在非活性状态。我们研究了通过抗 Müller 激素 2 型受体（Amhr2）的敲入等位基因驱动 Cre 表达并随后激活颗粒细胞以及输卵管和子宫基质细胞中的 mTOR，条件性敲除 TSC1 是否会影响雌性小鼠的生育能力。在所有检查的 AMHR2 表达组织中，核糖体蛋白 S6 的磷酸化增加，这是激活的 mTOR 的下游靶标，表明 TSC1 活性丧失。颗粒细胞中的 TSC1 缺失导致在 12 周龄的突变小鼠中检测到明显更少的原始卵泡，提示卵巢早衰，这可能与突变小鼠在发情期花费的时间显著增加有关。尽管与对照相比，优质排出的卵母细胞数量没有显著差异，但在正常和超排卵后退化卵母细胞的数量明显增加，表明卵母细胞质量受损。自然交配也显示在突变体中退化体的数量增加了几倍，这些突变体在双侧肿胀中收集，类似于由于近端输卵管阻塞而在所有检查的小鼠中形成的积水输卵管。试图将对照胚胎转移到突变子宫中也失败了，表明植入受到了损害。子宫内膜上皮细胞继续增殖，定量 RT-PCR 显示突变子宫中的植入窗期间 Mucin1 表达持续存在，孕激素受体 mRNA 表达没有任何变化，这表明一种不涉及破坏雌二醇调节的孕激素受体表达的机制。在小鼠的生殖道体细胞组织中纯合缺失 TSC1 会使雌性完全不孕，这可能是由于对卵泡募集、输卵管发育和胚泡植入的这些多效性影响所致。
