Spermatogonial stem cell regulation and maintenance of male fertility

项目摘要 15%的夫妇受到不孕不育的影响，其中约一半是男性伴侣导致不育 受孕吧。男性不育的一个原因是不能产生足够数量的精子。连续应答 强大的精子产生依赖于精原干细胞(SSCs)，SSCs具有 分裂以产生更多的SSCs，以及产生分化为精子的细胞。对SSC的监管 增殖和分化由一个复杂的调控环境控制，称为干细胞利基， 它由多种类型的睾丸细胞组成，包括支持细胞、间质细胞、肌样细胞和巨噬细胞。 此外，干细胞位于血管系统附近，这表明循环因子也有助于 SSC利基市场。这一复杂的利基市场如何管理SSC，以及SSC如何整合众多 利基市场提供的信号不被理解。研究管理SSC的监管机制 为了维护，这项研究利用了斑马鱼模型的遗传和实验属性。这项研究是 旨在了解被发现对SSC很重要的两个过程。AIM1将调查SSC维护 通过转录后RNA调节。我们的初步工作发现Adad1 RNA结合蛋白是 对建立或维护SSC至关重要。我们将检验这样一种假设，即RNA是由 Adad1 RNA结合蛋白是SSC调节和精子产生的关键蛋白。首先，要了解RNA是如何 调节控制SSC功能，将定义Adad1在SSC中调节的基本流程： 增殖、分化、停滞或凋亡。接下来，要发现受制于POST的机制- 在SSCs中转录RNA的调节，我们将识别Adad1靶RNA并询问靶标的稳定性 RNAs受Adad1影响。AIM2将研究中等组织应激源，高精子需求如何从 频繁繁殖，促进SSC激活和强劲的精子产生。我们之前的工作证明了 CDK21细胞周期调节器是维持繁殖雄性生殖系所必需的，但对于非繁殖雄性则不是。 繁殖的雄鱼。我们假设SSCs对中等应激源做出反应，如高精子需求， 通过引发一种扩散反应。此外，我们建议CDK21通过以下途径参与这一过程 激活静止的干细胞(QSC)群体。我们将测试野生型睾丸是否会激活一种增殖剂 对频繁繁殖的反应，以及这种反应是否涉及SSCs。此外，我们将测试cdk21是否 这种增殖反应所必需的，特别是如果它调节QSCs从静止状态退出。这个 拟议的实验将揭示基于RNA的调控如何通过 SSC法规。此外，这项研究可能揭示了整个组织对高精子需求的反应。 维持睾丸的动态平衡和强大的生育能力。从这项研究中获得的知识可以应用于 更好地了解人类生殖健康并改进诊断和治疗方法 不孕不育、辅助生殖技术和开发以男性为目标的计划生育方法。

Project Summary Infertility affects 15% of couples and in about half of these cases the male partner contributes to the failure to conceive. One cause of male infertility is an inability to produce adequate amounts of sperm. Continuous an robust sperm production is dependent on the spermatogonial stem cells (SSCs), which have the capacity to divide to produce more SSCs as well as produce cells that differentiate into sperm. The regulation of SSC proliferation and differentiation is controlled by a complex regulatory environment called the stem cell niche, which is comprised of several testicular cell types including, Sertoli, Leydig, myoid, and macrophages. Furthermore, SSCs are positioned near the vasculature suggesting that circulating factors also contribute to the SSC niche. How this complex niche manages the SSCs and how the SSCs incorporate the multitude of signals provided by the niche is not understood. To investigate regulatory mechanisms governing SSC maintenance, this study utilizes the genetic and experimental attributes of the zebrafish model. This study is aimed at understanding two processes found to be important for SSCs. Aim1 will investigate SSC maintenance by post-transcriptional RNA regulation. Our preliminary work identified the Adad1 RNA binding protein as essential for either SSC establishment or maintenance. We will test the hypothesis that RNA regulation by the Adad1 RNA binding protein is critical for SSC regulation and sperm production. First, to understand how RNA regulation controls SSC function, the basic processes regulated by Adad1 in SSCs will be defined: proliferation, differentiation, quiescence, or apoptosis. Next, to discover mechanisms subject to post- transcriptional RNA regulation in SSCs, we will identify Adad1 target RNAs and ask how stability of target RNAs is affected by Adad1. Aim2 will investigate how a moderate tissue stressor, high sperm demand from frequent breeding, promotes SSC activation and robust sperm production. Our previous work demonstrated that the Cdk21 cell-cycle regulator is necessary to maintain the germline in breeding males but not in non- breeding males. We hypothesize that the SSCs respond to moderate stressors, such as high sperm demand, by invoking a proliferative response. Furthermore, we propose that Cdk21 participates in this process through activation of the quiescent stem cell (QSC) population. We will test if the wild-type testis invokes a proliferative response to frequent breeding and if this response involves SSCs. Furthermore, we will test if cdk21 is required for this proliferative response and specifically if it regulates exit from quiescence in QSCs. The proposed experiments will reveal insights as to how RNA-based regulation promotes continued fertility through SSC regulation. In addition, this work may reveal a tissue-wide response to high sperm demand for maintenance of testis homeostasis and robust fertility. Knowledge gained from this study can be applied to a better understanding of human reproductive health and to improved methods for diagnosis and treatment of infertility, assisted reproductive technologies, and development of male-targeted family planning methods.