Resolving the Hierarchy and Regulation of Sebaceous Gland Stem Cells

项目总结 皮脂腺(Sgs)是哺乳动物皮肤的附属物，产生和分泌一种混合的脂类，已知 作为皮脂。皮脂的产生对皮肤的维持和正常皮脂产生的偏差至关重要 与几种皮肤病理有关，包括痤疮、寻常痤疮和脱发。皮脂的产生 皮脂细胞，SGS的组成细胞群。皮脂细胞经历了一个独特的成熟过程 随着细胞膜的破裂而达到顶峰。这个过程被称为全分泌性分泌，有助于 从SGS分泌皮脂，但结果导致皮脂细胞死亡。因为脂质周转是一个函数 皮脂细胞的周转、补充是维持SGS功能的关键。终生的营业额 皮脂细胞的形成需要持续的细胞供应来补充和维持腺体，这表明 干细胞在SG组织维持中的作用。然而，内在和外在机制 调节假定的SG干细胞活性的机制还没有很好的定义。这在一定程度上是由于限制。 静态组织学分析。这种实验性的方法只能及时捕获单张快照，这 不足以描绘具有快速周转率的组织中的分级组织。此外， 干细胞相关基因，如Sox9，在毛囊和SGS之间的重叠表达有限 我们能够解释这些标记在SG生理学中的功能作用，而不是从头发上耦合。要克服 在这些限制下，我将遗传谱系追踪工具与实时成像方法结合在一起，基于两种- 光子显微镜。这项研究的总体目标是通过结合现场直播实施综合方法 成像系统采用最先进的基因组学工具1)表征SG动态平衡中的干细胞动力学 以及2)分析关键分子信号如何影响皮脂细胞的命运， Sox9.在我的初步实验中，我发现来自毛囊峡部的细胞，相邻的隔间， Sox9的皮肤特异性敲除导致了SG萎缩。我假设 脂肪细胞由来自峡部的异质干细胞群补充，而SOX9是 它们的调节和SG生理所需的。本提案的目标1旨在分解皮脂细胞 并验证峡部在脑海绵状回再生中的必要性。本提案的目标2将解决 SOX9在调节皮脂细胞命运中的作用。本研究为研究SG提供了一种创新的方法 通过结合尖端成像技术和基因技术在自然组织环境中培育干细胞 工具。该提案的目标是通过解决以下问题来揭示SG维护的基本机制 调节皮肤中SG干细胞活性的皮脂细胞谱系和分子途径。

PROJECT SUMMARY Sebaceous glands (SGs) are appendages of mammalian skin that produce and secrete a mixture of lipids, known as sebum. Sebum production is crucial for skin maintenance and deviations in normal sebaceous lipid production are implicated in several skin pathologies including acne vulgaris and alopecia. Sebum production is carried out by sebocytes, the constituent cell population of SGs. Sebocytes undergo a unique maturation process which culminates with the rupture of the cell membrane. This process, termed holocrine secretion, facilitates the secretion of sebum from SGs, but consequently results in sebocyte death. As lipid turnover is a function of sebocyte turnover, sebocyte replenishment is critical to the functional maintenance of SGs. The lifelong turnover of sebocytes requires a continuous supply of cells to replenish and maintain the gland, which suggests the involvement of stem cells in the maintenance of SG tissues. However, the intrinsic and extrinsic mechanisms that regulate activity of the presumptive SG stem cells are not well defined. This is in part due to the limitations of static histological analyses. Such experimental approaches can only capture single snapshots in time, which are insufficient for delineating a hierarchical organization in a tissue with a rapid turnover rate. Furthermore, the overlapping expression of stem cell-associated genes, like Sox9, between the hair follicle and SGs has limited our ability to interpret the functional role of these markers in SG physiology uncoupled from the hair. To overcome these limitations, I have combined genetic lineage-tracing tools with live imaging approaches based on two- photon microscopy. The overall goal of this study is to implement an integrative approach by combining a live imaging system with state-of-the-art genomics tools to 1) characterize stem cell dynamics in SG homeostasis and regeneration by live imaging, and 2) analyze how sebocyte fate is influenced by the key molecular signal, Sox9. In my preliminary experiments, I found that cells from the hair follicle isthmus, an adjacent compartment, made cell contributions to SGs, and that skin-specific knockouts of Sox9 resulted in SG atrophy. I hypothesize that sebocytes are replenished by a heterogeneous stem cell population from the isthmus and that SOX9 is required for their regulation and SG physiology. Aim 1 of this proposal is designed to resolve the sebocyte lineage hierarchy and test the necessity of the isthmus in SG regeneration. Aim 2 of this proposal will address the functional role of SOX9 in regulating sebocyte fate. This research offers an innovative approach to study SG stem cells within the natural tissue environment by combining cutting-edge imaging technologies and genetic tools. The goal of this proposal is to uncover the fundamental mechanisms of SG maintenance by resolving the sebocyte lineage and molecular pathways that regulate SG stem cell activity in the skin.