APOPTOSIS AND REPRODUCTIVE AGING OF THE FEMALE

女性的细胞凋亡和生殖衰老

• 批准号: 2001548
• 负责人: Jonathan Lee Tilly
• 金额: $ 15.8万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-15 至 1998-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2001548
• 关键词: aging; apoptosis; autoradiography; complementary DNA; endonuclease; enzyme induction /repression; female; free radical oxygen; gene expression; glutathione peroxidase; gonadotropins; granulosa cell; hormone regulation /control mechanism; laboratory rat; messenger RNA; northern blottings; nucleic acid probes; ovary disorder; reproductive development; southern blotting; superoxide dismutase; tissue /cell culture

Although depletion of the ovarian follicle pool plays a critical role in reproductive aging in the human female, the events underlying follicular atresia remain to be elucidated. It is well-established that apoptosis, a form of physiological cell death, is important for remodeling of tissues and removal of transient cell populations. Moreover, the penultimate controlling events which initiate or suppress physiological cell death may involve a conserved cohort of "cell death" proteins, and the fate of cells may be decided by the ratio of death repressors (Bcl-2, Bcl-x/long) to death inducers (Bax, Bcl-x/short). The mechanisms of action of these proteins have not been fully clarified. However, there is evidence that Bcl-2 functions as an antioxidant to protect cells from damage by reactive oxygen species such as superoxide anion, peroxide, and hydroxyl radical. It is possible that these death repressor proteins (Bcl-2, Bcl-x/long) are components of a family of oxidative stress response proteins which also includes superoxide dismutase (SOD; an enzyme which catalyzes conversion of superoxide anion to hydrogen peroxide) and glutathione peroxidase (GSHPx; an enzyme which converts hydrogen peroxide to water). As recent studies conducted by the PI have revealed that granulosa cell death during atresia in all species studied thus far, including humans, is mediated via apoptosis, it is hypothesized that follicular atresia is initiated by a shift in the ratio of death repressor to death inducer gene expression. The altered expression of these cell death genes would then lead to insufficient protection of granulosa cells from the damaging effects of reactive oxygen species. To test this hypothesis, the Specific Aims of this proposal are to: 1) characterize changes in the levels of mRNA encoding bcl-2, bax, bcl-x (long and short), SOD and GSHPx during maturation of rat ovarian follicles from the primordial to antral stage of development; 2) evaluate if gonadotropin-mediated inhibition of apoptosis in granulosa cells of rat antral follicles in vivo and in vitro is associated with enhanced bcl-2, bcl-x/long, SOD and GSHPx, and suppressed bax and bcl-x/short, gene expression; 3) determine if selective destruction of the bcl-2, bcl- x/long, SOD and GSHPx genes by the apoptotic endonuclease contributes to a loss of death repressor gene expression during granulosa cell apoptosis and atresia; 4) investigate if inhibitors of oxidative free radical damage prevent apoptosis in granulosa cells of rat antral follicles incubated in vitro without trophic hormone support; and, 5) determine if inducers of oxidative free radical damage interfere with the ability of gonadotropins to inhibit apoptosis in granulosa cells of rat antral follicles incubated in vitro.

尽管卵巢卵泡池的消耗在 人类女性的生殖衰老，卵泡的基础事件 闭锁仍有待阐明。 凋亡是良好的， 一种生理细胞死亡的形式，对于重塑 组织和瞬态细胞群体的去除。 而且， 倒数倒数的控制事件，启动或抑制生理 细胞死亡可能涉及保守的“细胞死亡”蛋白质，并且 细胞的命运可以取决于死亡阻遏物的比率（Bcl-2， BCl-X/Long）到死亡诱导者（Bax，Bcl-X/Short）。 机制 这些蛋白质的作用尚未完全阐明。 但是，那里 证据表明Bcl-2是保护细胞免受的抗氧化剂的作用 活性氧的损害，例如超氧化物阴离子，过氧化物和 羟基。 这些死亡阻遏蛋白可能有可能 （Bcl-2，Bcl-X/Long）是氧化应激家族的组成部分 反应蛋白，还包括超氧化物歧化酶（SOD； 催化超氧化阴离子转化为氢的酶 过氧化物）和谷胱甘肽过氧化物酶（GSHPX；转化的酶 过氧化氢至水）。 正如PI最近进行的那样 揭示了所有研究的物种中闭锁过程中颗粒细胞死亡 到目前为止，包括人类在内，是通过凋亡介导的，它是被假设的 卵泡闭锁是通过死亡比率的变化而引发的 死亡诱导剂基因表达的阻遏物。 表达的改变 这些细胞死亡基因然后将导致对 颗粒细胞来自活性氧的破坏作用。 为了检验这一假设，该提议的具体目的是：1） 表征编码Bcl-2，Bax，Bcl-X的mRNA水平的变化 （长和短），大鼠卵巢成熟期间的SOD和GSHPX 卵泡从原始到发育的狂热阶段； 2）评估 如果促性腺激素介导的抑制在颗粒细胞中凋亡的抑制作用 大鼠体内和体外的大鼠肛门卵泡与增强 Bcl-2，Bcl-X/Long，SOD和GSHPX，以及抑制Bax和Bcl-X/Short， 基因表达； 3）确定是否有选择性破坏Bcl-2，Bcl- 凋亡性核酸内切酶的X/Long，SOD和GSHPX基因有助于 颗粒细胞凋亡期间死亡阻遏基因表达的损失 和闭锁； 4）研究氧化自由基的抑制剂是否 损害可预防大鼠肛门卵泡的颗粒细胞凋亡 在体外孵育，无营养激素支持； 5）确定是否 氧化自由基损伤的诱导者会干扰 促性腺激素抑制大鼠肛门颗粒细胞的凋亡 卵泡在体外孵育。