MicroRNA-mediated regulation in mammalian skin

 描述(申请人提供)：哺乳动物的皮肤及其附属物作为身体最外层的屏障，保护内部器官免受环境危害，并将必要的液体保留在体内。了解皮肤发育的分子机制是未来应用于再生医学和开发人类疾病治疗方法的重要前提。许多调控机制，包括细胞信号、细胞骨架重塑、转录和表观遗传调控以及转录后调控，在皮肤发育中起着重要作用。在这些机制中，microRNA介导的转录后调控对转录组的输出具有广泛的控制作用。这些非编码的RNA分子广泛地调控着大量(哺乳动物中约60%)的基因，并在广泛的生物学过程中发挥着重要作用。在哺乳动物皮肤中，miRNA途径在胚胎和新生儿皮肤发育中的关键作用已得到很好的认识。然而，单个microRNA的功能和潜在机制仍然知之甚少。特别是，在毛囊形态发生中发挥重要作用的microRNAs尽管受到了广泛的关注，但仍然未知。为了解决这个重要的问题，我们建议将重点放在miR-200家族上，这是一个在毛发胎盘中高表达的microRNA家族。重要的是，miR-200 microRNAs在皮肤中的丢失会导致毛胚形成缺陷，这与它们在皮肤中的重要功能是一致的。我们将在体外研究它们在原代角质形成细胞中的作用，以及在体内的毛发胎盘中的作用(目标1和2)。为了提供对它们功能的机械性见解，我们将对WT和miR-200基因敲除小鼠应用microRNAs及其相关mRNA靶标的生化纯化，并以毛发胎座特异的方式识别miR-200相关靶标。我们将集中精力全面识别miR-200在调节细胞增殖、黏附和迁移方面的重要靶点以及皮肤中的重要信号通路。该项目的长期目标是阐明单个microRNA的功能，并在皮肤发育过程中提供对这些分子的机械洞察，尤其是毛发的形态发生。从这些研究中获得的知识将为操纵新生皮肤祖细胞中的microRNAs用于再生医学铺平道路，并加深我们对microRNAs在皮肤癌中的作用的理解。

 DESCRIPTION (provided by applicant): Mammalian skin and its appendages function as the outermost barrier of the body to protect inner organs from environmental hazards and keep essential fluids within the body. Understanding molecular mechanisms that operate in skin development is an important prerequisite for future applications in regenerative medicine and for developing therapeutic treatment for human disease. Many regulatory mechanisms including cell signaling, cytoskeleton remodeling, transcriptional and epigenetic controls and post-transcriptional regulation have been implicated to have important roles in skin development. Among these mechanisms, microRNA-mediated post-transcriptional regulation exerts a widespread control over the output of the transcriptome. These noncoding RNA molecules broadly modulate a large number (~60% in mammals) of genes and play important roles in a wide range of biological processes. In mammalian skin, the critical functions of the miRNA pathway in embryonic and neonatal skin development have been well appreciated. However, individual microRNA functions and the underlying mechanisms remain poorly understood. In particular, microRNAs that play important roles in hair follicle morphogenesis are unknown despite extensive interests. To address this important issue, we propose to focus on the miR-200 family, a highly expressed microRNA family in the hair placode. Importantly, the loss of the miR-200 microRNAs in the skin leads to defective hair germ formation, consistent with their important functions in the skin. We will examine their roles in primary keratinocytes in vitro and in the hair placode in vivo (Aim 1 and 2). To provide mechanistic insights for their functions, we will apply biochemical purification of microRNAs and their associated mRNA targets to the WT and miR-200 knockout mice and identify miR-200-associated targets in a hair placode-specific manner. We will focus on comprehensively identifying important targets of miR-200 in regulation of cell proliferation, adhesion and migration as well as important signaling pathways in the skin. The long-term goal of this project is to elucidate individual microRNA functions and provide mechanistic insights to these molecules during skin development with a particular focus on hair morphogenesis. The knowledge gained from these studies will pave the way to manipulate microRNAs in neonatal skin progenitor cells for regenerative medicine and enhance our understanding for microRNAs' roles in skin cancer.