Novel Male Contraceptive Agents that Target HSP90 and Elongation Factor 1A

世界卫生组织（世卫组织）的统计数据显示，全世界每年有2亿多怀孕者， 8700万次怀孕（42%）是意外怀孕。尽管有女性避孕药具， 在避孕方法和避孕套方面，据报告，在一半的意外怀孕中， 避孕药具，4 600万怀孕被堕胎终止。因此，NIH、IOM和WHO 确定需要开发新型可逆口服非激素男性避孕药。长期 我们的研究目标是：1）确定睾丸或精子中对男性生育力重要的可行靶点， 开发可逆的男性避孕药，2）发现，设计，测试， 证明了抑制这些睾丸的新型非激素小分子药物的概念验证，或 精子目标我们已经开发了H2-吲唑，作为一类新的吲唑羧酸， 特别是导致精子细胞从睾丸中过早释放。H2-咪唑是一种非常有前途的 NICHD目前正在评估的一种有效和可逆的非激素男性避孕药， 为人类临床试验做准备。甘氨唑与两种新的睾丸蛋白靶点Hsp 90 p和 eEF 1A将被用于设计和合成新的男性避孕药。为此中央 中心假设是新的小分子抑制了睾丸中HspSOp和eEF 1A的功能， 抑制剂导致可逆的晚期抗生精避孕。为了达到设计的目的， 新的男性避孕药，将实现以下具体目标： 1.鉴定与Hsp 90或eEF 1 A结合的化学上不同的小分子，如格列吡唑， 确定它们的抗精子生成功效 2.确定热休克蛋白90和eEF 1 A中格列吡唑类似物的结合位点，并描绘其三维结构。 对接位点内的蛋白质-格列吡唑相互作用 3.定义Hsp 90和eEF 1 A抑制剂可逆性抗精子生成的作用机制 具体目标将通过尖端药物发现和分子方法来实现，包括 高通量筛选超过120，000种化合物，Hsp 90和eEF 1A药物蛋白的X射线晶体学 共晶体、三维建模和结构活性关系（SAR），以改进先导避孕药 药物，并使用分子、细胞生物学和蛋白质组学定义药物的作用机制 确定可逆与不可逆抗精子生成男性避孕药靶点的方法。 新药物是精子发生的可逆抑制剂的概念验证将提供 具有新化学结构的NIH，可作为格列吡唑的药理学替代品添加， 药物开发和临床试验作为可逆的非激素口服男性避孕药。

World Health Organization (WHO) statistics show that of the over 200 million pregnancies worldwide per year, 87 million pregnancies (42%) were unintended. In spite of the availability of female contraceptive methods and condoms, in half of the unintended pregnancies the women reported to be using a contraceptive, and 46 million pregnancies were terminated by abortion. Thus, the NIH, IOM, and WHO have identified the need to develop novel reversible oral non-hormonal male contraceptive agents. The long term goals of our research are 1) to identify viable targets in testis or in sperm important for male fertility that can be exploited for development as reversible male contraceptive agents, and 2) to discover, design, test, and demonstrate proof-of concept for novel non-hormonal small molecule agents that inhibit these testis or sperm targets. We have developed H2-Gamendazole, as a new class of indazole carboxylic acids that specifically cause premature release of spermatids from the testis. H2-Gamendazole is a highly promising potent and reversible non-hormonal male contraceptive agent that NICHD is currently evaluating in preparation towards human clinical trials. Gamendazoles bind to two novel testis protein targets, Hsp90p and eEF1A that will be exploited for design and synthesis of new male contraceptive agents. To this end, the central hypothesis is that the reduction in function of HspSOp and eEF1A in testis by novel small molecule inhibitors results in reversible late-stage anti-spermatogenic contraception. To achieve the goal of designing new male contraceptive agents, the following Specific Aims will be accomplished: 1. Identify chemically distinct small molecules that bind to Hsp90¿ or eEF1 A like Gamendazole and determine their anti-spermatogenic efficacy 2. Define the binding site for Gamendazole analogues within Hsp90¿ and eEF1 A and delineate the 3-D protein-Gamendazole interactions within the docking sites 3. Define the mechanism of action of Hsp90¿ and eEF1 A inhibitors that are reversibly antispermatogenic The specific aims will be accomplished by cutting edge drug discovery and molecular approaches including high throughput screening of over 120,000 compounds, x-ray crystallography of Hsp90 and eEF1A drugprotein co-crystals, 3-D modeling and structure activity relationships (SAR) to refine lead contraceptive agents, and definition of the mechanism of action of the drug using molecular, cell biological, and proteomic approaches to define targets of reversible versus irreversible anti-spermatogenic male contraceptive agents. Proof-of-concept demonstration that the new agents are reversible inhibitors of spermatogenesis will provide NIH with new chemical structures that can be added as pharmacological alternatives to Gamendazole for drug development and clinical trials as reversible non-hormonal oral male contraceptives.