Mechanism of Metformin Action in Normal and PCOS Theca Cells

二甲双胍在正常和 PCOS 卵泡膜细胞中的作用机制

• 批准号: 8097119
• 负责人: Jan M McAllister
• 金额: $ 15.18万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8097119
• 关键词: 5' -AMP-activated protein kinase; Abbreviations; Acute; Affect; Age; Anabolism; Androgens; Anovulation; Biguanides; Bromodeoxyuridine; CREB1 gene; CYP11A1 gene; Cell Cycle Checkpoint; Cell Cycle Progression; Cell Cycle Regulation; Cell Proliferation; Cell Separation; Cells; Characteristics; Cholesterol; Cyclic AMP; Cytochrome P450; Data; Defect; Development; Dose; Endometrial Hyperplasia; Evaluation; Family member; Fertility; Flow Cytometry; Functional disorder; Gene Expression; Growth; Hyperandrogenism; Hypertrophy; In Vitro; Infertility; Insulin; Insulin Resistance; Maps; Mediating; Metformin; Mitotic Cell Cycle; Mixed Function Oxygenases; Modality; Non-Insulin-Dependent Diabetes Mellitus; Ovarian; Ovarian Cysts; Ovary; Ovulation; Patients; Periodicity; Pharmaceutical Preparations; Phenotype; Phosphorylation; Phosphotransferases; Physiological; Plasma; Play; Polycystic Ovary Syndrome; Publishing; Regulation; Reporting; Role; STK11 gene; Side; Signal Pathway; Signal Transduction; Site; Testing; Transducers; United States; Woman; Women' s Group; adenylate kinase; basal insulin; cell growth; clinically relevant; dehydroepiandrosterone; improved; insight; insulin sensitizing drugs; interest; member; new therapeutic target; novel; novel therapeutics; public health relevance; reproductive; research study; salt-inducible kinase; theca cell; upstream kinase

DESCRIPTION (provided by applicant): The use of the biguanide drug, metformin, is standard for young women with type 2 diabetes and is becoming prevalent for the treatment of hyperandrogenism and anovulation in women with polycystic ovary syndrome (PCOS). In vitro studies have shown that metformin has direct effects on inhibiting ovarian thecal androgen biosynthesis, which is of clinical relevance to both groups of women. However, the mechanism(s) by which metformin inhibits ovarian androgen biosynthesis is presently unclear. Our preliminary studies suggest that metformin treatment has differential effects on inhibiting androgen biosynthesis in theca cells propagated from normal cycling and PCOS women. An examination of the classical metformin activated LKB1/ AMP-activated protein kinase (AMPK) signaling cascade, provided the novel findings that LKB1 phosphorylation, as well as AMPK activity are decreased in PCOS theca cells. Metformin treatment corrected these signaling defects in PCOS theca cells, while inhibiting androgen biosynthesis. In this proposal we will test the hypothesis that defects in LKB1/AMPK signaling in PCOS theca cells contribute to increased androgen biosynthesis and disrupted cell growth in the PCOS ovary. In Specific Aim 1, we will investigate the underlying mechanism(s) by which metformin activates the LKB1/AMPK signaling pathway(s) to inhibit androgen biosynthesis in PCOS theca cells. We will examine the role(s) of LKB1, AMPK, and the salt inducible kinases, SIK1 and SIK2, in metformin inhibition of CYP17 and CYP11A1 gene expression and androgen biosynthesis in normal and PCOS theca cells propagated in long-term culture. The pathological characteristic of the PCOS ovary is that of multiple, small, growth arrested follicles. However, there have been no reports comparing cell growth or cell cycle control in normal and PCOS theca cells. We have identified differences in cell cycle regulation in normal and PCOS theca cells, and observed that metformin treatment of PCOS theca cells was observed to change PCOS and cell cycle progression to a normal phenotype. In Specific Aim 2, we will identify cell growth and cell cycle defects in PCOS theca cells and explore the signaling mechanism(s) involved in metformin's ability to correct these defects. The roles of LKB1, AMPK, and SIK1/2 in metformin-dependent cell growth and cell cycle progression, under normal physiological and hyperinsulinemic conditions, will be evaluated. We believe a clear understanding of mechanism(s) by which metformin signals to mediate inhibition of androgen biosynthesis and modulate cell growth in PCOS theca cells will help elucidate the pathophysiology of PCOS, and provide insight for the development of new therapeutic targets for PCOS. PUBLIC HEALTH RELEVANCE: Polycystic ovary syndrome (PCOS) is characterized by ovarian cysts, anovulation, hyperandrogenism, and endometrial hyperplasia, and affects 6-10% of reproductive age women, approximately 3-5 million women in the United States alone. Hyperandrogenism and anovulation in women with PCOS can be clinically treated with administration of the insulin sensitizing drug, metformin, a treatment for type 2 diabetes, however the mechanisms by which metformin directly modulates the ovary have not been examined. A rigorous evaluation of the mechanism(s) by which the metformin activates the LKB1/AMPK signaling pathway(s) to correct defects in androgen biosynthesis and cell growth in PCOS theca cells, will provide essential insight for the development of new therapeutic modalities for PCOS.

描述（由申请人提供）：使用Biguanide药物二甲双胍是2型糖尿病的年轻女性的标准，并且在治疗多囊卵巢综合征（PCOS）女性的过度雄激素和发酵症的治疗方面已经变得越来越普遍。体外研究表明，二甲双胍对抑制卵巢蛋白雄激素生物合成有直接影响，这与两组妇女均具有临床相关性。但是，二甲双胍抑制卵巢雄激素生物合成的机制目前尚不清楚。我们的初步研究表明，二甲双胍治疗对抑制正常循环和PCOS妇女传播的theca细胞的雄激素生物合成具有不同的影响。对经典二甲双胍激活的LKB1/ AMP激活的蛋白激酶（AMPK）信号级联的检查，前提是PCOS THECA细胞中LKB1磷酸化以及AMPK活性的新发现。二甲双胍处理纠正了PCOS theca细胞中的这些信号缺陷，同时抑制了雄激素生物合成。在此提案中，我们将检验以下假设：PCOS theca细胞中LKB1/AMPK信号的缺陷有助于增加雄激素生物合成并破坏PCOS卵巢的细胞生长。在特定目标1中，我们将研究二甲双胍激活LKB1/AMPK信号通路以抑制PCOS theca细胞中雄激素生物合成的潜在机制。我们将研究LKB1，AMPK和盐诱导激酶Sik1和Sik2的作用，在二甲双胍抑制CYP17和CYP11A1基因表达和雄激素生物合成中，在长期培养中传播的正常​​和PCOS THECA细胞中。 PCOS卵巢的病理特征是多个，小的生长捕集的卵泡。但是，没有报告比较正常和PCOS theca细胞中细胞生长或细胞周期控制的报道。我们已经确定了正常和PCOS theca细胞中细胞周期调节的差异，并观察到观察到PCOS theca细胞的二甲双胍治疗可将PCOS和细胞周期进程更改为正常表型。在特定的目标2中，我们将确定PCOS theca细胞中的细胞生长和细胞周期缺陷，并探讨二甲双胍纠正这些缺陷能力所涉及的信号传导机制。在正常的生理和高胰岛素条件下，LKB1，AMPK和SIK1/2在二甲双胍依赖性细胞生长和细胞周期进程中的作用将得到评估。我们认为，对二甲双胍信号介导对雄激素生物合成的抑制和调节PCOS theca细胞中细胞生长的机制有清晰的理解，将有助于阐明PCOS的病理生理学，并为PCOS的新治疗靶标提供洞察力。 公共卫生相关性：多囊性卵巢综合征（PCOS）的特征是卵巢囊肿，发作，多雄激素和子宫内膜增生，并影响6-10％的生殖年龄妇女，仅在美国，大约3-5万妇女。可以通过胰岛素敏化药物，二甲双胍，一种治疗2型糖尿病的治疗方法在临床上治疗PCOS女性的高狂力和无排卵，但是尚未检查二甲双胍直接调节卵巢的机制。对二甲双胍激活LKB1/AMPK信号通路的机制进行了严格的评估，以纠正PCOS THECA细胞中雄激素生物合成和细胞生长的缺陷，将为PCOS的新疗法形态发展提供基本的见解。