Male Nonhormonal Contraception Via Sphingolipid Biosynthesis Inhibitors

描述(申请人提供)：避孕方法使用荷尔蒙来阻止生殖细胞成熟或通过手术或屏障干扰精子-卵子融合。在实施计划生育的约6亿对夫妇中，男性仅限于避孕套和输精管结扎术，但男性占所有避孕措施的三分之一。由于现有男性方法的缺陷，研究人员试图为男性开发更多的可逆避孕药。最广泛测试的方法是使用外源性睾酮来抑制促性腺激素的释放，从而使睾丸失去精子发生所需的信号。缺点包括观察到一些男性对荷尔蒙干扰没有反应，无精子症的发病延迟了3个月；因此，需要开发非荷尔蒙方法来避孕。研究人员注意到，天生缺乏鞘糖脂(GSL)的雄性小鼠是不育的，但在所有其他方面都是正常的。这表明，GSL生物合成的抑制剂可能为非激素男性避孕方法的发展提供了一个新的范例。研究表明，雄性小鼠在接受米卢斯特治疗时会导致不育，米卢斯特是一种鞘磷脂模拟物，在停药后这种效果是完全可逆的。这种被批准用于人类治疗高谢病的仿制品，抑制了葡萄糖转移酶，葡萄糖转移酶负责将神经酰胺生物合成转化为脑苷脂。经过处理的小鼠的精子显示出异常的形态，缺乏顶体抗原，但具有遗传能力。不幸的是，由于未知的原因，这种分子在人类或高等物种中没有类似的作用。为了更好地了解鞘糖脂抑制在精子发生中的作用，我们已经确定了抑制GSL产生或导致GSL耗竭的化合物，并将在体内测试它们的抗生育潜力。该项目的目标是探索神经鞘糖脂生物合成抑制剂导致可逆性男性不育的能力。

DESCRIPTION (provided by applicant): Contraceptive methods use hormones to prevent germ cell maturation or interfere with sperm-egg fusion via surgery or barriers. Of the ~600 million couples that employ family planning, males are limited to condoms and vasectomies, yet men account for one-third of all contraception. Because of drawbacks to current existing male methods researchers have attempted to develop additional reversible contraceptives for men. The most extensively tested approach utilizes the administration of exogenous testosterone to suppress gonadotropin release thereby depriving the testes of the signals required for spermatogenesis. Drawbacks include the observation that some men fail to respond to hormonal interference and there is a 3-month delay in the onset of azoospermia; therefore, the development of non-hormonal approaches to male contraception is needed. Researchers have noted that male mice inherently devoid of glycosphingolipids (GSL) are sterile but normal in all other aspects. This suggests that inhibitors of GSL biosynthesis may provide a new paradigm for the development of non-hormonal methods of male contraception. Studies have demonstrated that male mice are rendered infertile when treated with miglustat, a sphingolipid mimic, an effect which is fully reversible after discontinuation. This mimic, approved for use in humans for the treatment of Gaucher's disease, inhibits glucosyl transferase, an enzyme responsible for the biosynthetic conversion of ceramide to cerebroside. Sperm from treated mice display abnormal morphologies and lack acrosome antigens but are genetically competent. Unfortunately, for unknown reasons this molecule does not have similar effects in humans or higher species. To better understand the role of glycosphingolipid inhibition in spermatogenesis, we have identified compounds that either inhibit the production or cause the depletion of GSL and will test their in vivo anti-fertility potential. The goal of this project is to explore the ability of glycosphingolipid biosynthesis inhibitors to cause reversible male infertility.