Understanding molecular mechanisms of male fertility and the link to motile cilia

了解男性生育力的分子机制以及与活动纤毛的联系

• 批准号: BB/V011251/1
• 负责人: Hannah Mitchison
• 金额: $ 117.16万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FV011251%2F1
• 关键词: Understanding; molecular; mechanisms; male; fertility

Reproductive success is crucial for the preservation of species and sustainable agriculture and food, in addition to being essential to human health. In human populations, poor sperm quality is a noteworthy vulnerability that explains around half of infertility cases but remains very little understood. In this study we propose to study the fundamental basis of male factor fertility in order to shed fresh light in this research area. We propose that there is a major but overlooked role of male-specific motile cilia in the production of healthy, fertile sperm. This proposal is focussed on characterizing new genetic factors in male fertility and exploring the balance of sperm and cilia requirements to develop and release healthy male reproductive cells (gametes). Cilia are hair-like organelles extending outside a cell and motile cilia are required in certain specialised areas of the body, for example in our airways beating of cilia lining the lung and upper airways are responsible for mucus flow and pathogen removal. The role of motile cilia in efferent ducts that are unique to male humans, is poorly understood. The efferent ducts are tubules that allow sperm made in the testis to be released into the ejaculatory duct via a structure called the epididymis. Sperm develop in the testis and are transported through the efferent ducts and epididymis, where they undergo maturation as they proceed, with growth of the sperm tail (flagella) giving them motility. Only after this transport do the sperm reach their full fertilizing capacity. In the testis (seminiferous tubules), male germ cells undergo several steps to become highly specialized spermatozoa. This process requires precisely timed gene expression and correct protein function in order to produce fertile sperm and ensure reproductive success. Malfunction of proteins at any time point during this process results in compromised sperm development. Therefore, we aim to characterize the function of genes identified in genetic screens of infertile male patients, using fly as a model organism because spermatogenesis is a conserved process with similar genes coding for proteins in fly and man. Our experiments will help us to define the link between genetics and male fertility in evolutionary conserved processes. The last phase of spermatogenesis involves formation of the sperm tail. The core structure of the motile cilia and sperm tail is almost identical, but with recently identified protein differences. These differences will be elucidated and the effect of specific genetic mutations on male fertility through sperm tail and/or efferent duct cilia functions characterized. To do this, we will examine the sperm quality and structure in patients a disease caused by mutations of the motile cilia in airways, as they have high male fertility that is not well characterised yet. The motility pattern of different cilia types (airway, efferent duct) and sperm are different and therefore we hypothesize that their motility producing complexes also differ. We will investigate motility-producing dynein composition and assembly, in sperm from humans with cilia mutations and in efferent duct cilia from mice with cilia mutations. We speculate that efferent duct cilia may interact with sperm through molecules they release in special packets (vesicles) and we aim to investigate the presence and role of this crosstalk in mouse mutants where the cilia specific protein transport is inhibited. Furthermore, we will develop a cell culture model to study the importance of cilia motility and other characteristics to better explore their role in production of fertile sperm. Overall, these experiments aim to clarify the molecular mechanisms underlying cilia related fertility and identify the influences of cilia versus sperm related mechanisms in successful sperm development in mammals.

除了对人类健康至关重要外，生殖成功对于物种的保护以及可持续农业和粮食的保护也至关重要。在人类群体中，精子质量差是一个值得注意的弱点，可以解释大约一半的不孕症病例，但仍然知之甚少。在这项研究中，我们建议研究男性因素生育的基本基础，以期为这一研究领域提供新的线索。我们认为，男性特有的活动纤毛在健康、可育精子的产生中起着重要但被忽视的作用。这项建议的重点是表征男性生育能力的新遗传因素，并探索精子和纤毛的平衡需求，以发展和释放健康的男性生殖细胞(配子)。纤毛是延伸到细胞外的毛状细胞器，身体的某些特殊区域需要活动的纤毛，例如，在我们的呼吸道中，纤毛排列在肺内，上呼吸道负责粘液流动和病原体清除。活动纤毛在传出管道中的作用是男性独有的，但人们对此知之甚少。传出管是允许在睾丸中产生的精子通过一种称为附睾管的结构释放到射精管中的小管。精子在睾丸中发育，并通过传出管道和附睾运输，在那里它们在进行过程中经历成熟，精子尾部(鞭毛)的生长使它们具有活力。只有在这种运输之后，精子才能达到完全的受精能力。在睾丸(生精小管)中，雄性生殖细胞经历几个步骤才能成为高度特化的精子。这一过程需要精确的基因表达和正确的蛋白质功能，才能产生受精并确保生殖成功。在这一过程中，任何时间点的蛋白质故障都会导致精子发育受阻。因此，我们的目标是以苍蝇为模式生物，研究在不育男性患者的遗传筛查中发现的基因的功能，因为精子发生是一个保守的过程，在苍蝇和人类中，编码蛋白质的基因相似。我们的实验将帮助我们在进化保守的过程中确定遗传学和男性生育能力之间的联系。精子发生的最后阶段涉及精子尾部的形成。活动纤毛和精子尾巴的核心结构几乎相同，但与最近发现的蛋白质差异。这些差异将被阐明，并描述特定基因突变通过精子尾巴和/或传出管纤毛功能对男性生育能力的影响。为了做到这一点，我们将检查患者的精子质量和结构，这是一种由呼吸道活动纤毛突变引起的疾病，因为他们具有高男性生育力，目前还没有很好的特征。不同纤毛类型(呼吸道、传出管)和精子的运动模式不同，因此我们推测它们的运动产生复合体也不同。我们将在纤毛突变的人类精子和纤毛突变的小鼠的传出管纤毛中研究动力蛋白的组成和组装。我们推测，传出纤毛可能通过它们在特殊包(囊泡)中释放的分子与精子相互作用，我们的目标是研究这种串扰在纤毛特异性蛋白运输被抑制的小鼠突变体中的存在和作用。此外，我们将开发一个细胞培养模型来研究纤毛运动和其他特征的重要性，以更好地探索它们在生产可育精子中的作用。总体而言，这些实验旨在阐明纤毛相关生育的分子机制，并确定纤毛与精子相关机制在哺乳动物精子成功发育中的影响。

项目成果

The piRNA-pathway factor FKBP6 is essential for spermatogenesis but dispensable for control of meiotic LINE-1 expression in humans.

• DOI: 10.1016/j.ajhg.2022.09.002
• 发表时间: 2022-10-06
• 期刊: American journal of human genetics
• 影响因子: 9.8

CFAP300 mutation causing primary ciliary dyskinesia in Finland.

• DOI: 10.3389/fgene.2022.985227
• 发表时间: 2022
• 期刊: FRONTIERS IN GENETICS
• 影响因子: 3.7
• 作者: Schultz, Ruediger;Elenius, Varpu;Fassad, Mahmoud R.;Freke, Grace;Rogers, Andrew;Shoemark, Amelia;Koistinen, Tiina;Mohamed, Mai A.;Lim, Jacqueline S. Y.;Mitchison, Hannah M.;Sironen, Anu I.
• 通讯作者: Sironen, Anu I.