Metabolic Regulation of Epidermal Homeostasis

描述（由申请人提供）：为了维持其保护功能，表皮经历了一个持续的稳态更新过程，在这个过程中，增殖基底层内的细胞退出细胞周期，并在基底上表皮层中分化。与表皮角质形成细胞分化相关的形态学和遗传学变化得到了很好的描述。其他分子机制，如代谢重编程如何调节表皮稳态，尚未得到广泛研究。我们最近证明，线粒体氧化代谢和活性氧（ROS）的产生是促进角质细胞分化的关键调节因子。缺乏线粒体代谢和基底表皮细胞ROS生成的小鼠表现出表皮分化受损和增生性基底细胞水平增加。我们进一步证明，线粒体产生的ROS作为关键的信号分子，促进Notch信号事件的传播，这是角质形成细胞分化所必需的。在目前的提案中，我们将以我们最近报道的发现为基础，极大地扩展我们对表皮分化程序如何调节细胞代谢以促进分化或维持基底细胞处于未分化状态的理解。我们将重点关注p63，这是表皮发育和体内平衡所需的转录因子。p63属于一个转录因子家族，已知是细胞代谢和ROS水平的调节因子。我们将使用功能的获得和丧失研究来确定p63表达如何影响角化细胞糖酵解和氧化代谢。我们将仔细研究p63表达如何通过生物合成途径影响代谢物通量，以及p63表达如何影响细胞ROS水平。我们还将探索已知的p63对Notch的抑制作用。我们将确定p63是否通过抑制ros介导的信号传导来调节Notch。我们的研究将确定在分化过程中角质细胞代谢是如何变化的，并将确定代谢重编程在促进分化中所起的因果作用。本文提出的工作将为申请人提供发展成为独立皮肤生物学家所需的培训。该提案建立在申请人现有优势的基础上，并通过表皮和上皮生物学的额外培训增加了他的能力。西北大学目前的协作环境将确保这项工作迅速有效地完成。重要的是，本提案中提供的培训将使申请人有时间利用西北大学提供的职业发展机会。这些课程包括拨款写作、指导、教学和负责任的研究行为。

DESCRIPTION (provided by applicant): In order to maintain its protective function, the epidermis undergoes a continual process of homeostatic renewal in which cells within the proliferative basal layer withdraw from the cell cycle and differentiate as they process through the suprabasal epidermal layers. The morphological and genetic changes associated with epidermal keratinocyte differentiation are well described. How other molecular mechanisms, such as metabolic reprogramming regulate epidermal homeostasis, have not been extensively studied. We recently demonstrated that oxidative mitochondrial metabolism and reactive oxygen species (ROS) production are critical regulators which promote keratinocyte differentiation. Mice which lacked mitochondrial metabolism and ROS generation in basal epidermal cells exhibited impaired epidermal differentiation and increased levels of proliferative basal cells. We further demonstrated that ROS produced at mitochondria act as critical signaling molecules which promote the propagation of Notch signaling events which are required for keratinocyte differentiation. In the current proposal, we will build on our recently-reported findings to dramatically extend our understanding of how the epidermal differentiation program regulates cellular metabolism to promote differentiation or to maintain basal cells in the undifferentiated state. We will focus our attention on p63, a transcription factor required for epidermal development and homeostasis. p63 belongs to a family of transcription factors which are known to be regulators of cellular metabolism and ROS levels. We will use gain and loss of function studies to determine how p63 expression affects keratinocyte glycolytic and oxidative metabolism. We will closely examine how p63 expression affects metabolite flux through biosynthetic pathways and how p63 expression affects levels of cellular ROS. We will also explore the known repressive effect that p63 has on Notch. We will determine if p63 regulates Notch through repression of ROS-mediated signaling. Our studies will determine how keratinocyte metabolism changes during differentiation and will determine the causal role that metabolic reprogramming plays in promoting differentiation. The work proposed herein will provide the applicant with the training required for development into an independent skin biologist. This proposal builds off of the existing strengths of the applicant and adds to his abilities with additional training in epidermal and epithelial biology. The collaborative environment present at Northwestern University will ensure that the work is completed expeditiously and efficiently. Importantly, the training provided for in this proposal will allow applicant time to take advantage of opportunities for career development available at Northwestern University. These include workshops in grant writing, mentoring, teaching, and responsible conduct of research.