Investigating the role for Utrophin in age-related decline of the Merkel lineage

研究 Utropin 在默克尔谱系年龄相关衰退中的作用

• 批准号: 10289985
• 负责人: DAVID M OWENS
• 金额: $ 32.82万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10289985
• 关键词: Address; Adult; Age; Age-Months; Age-Years; Aging; Alleles; Apoptosis; Behavior; Cell Count; Cell Lineage; Cell Maintenance; Cell Survival; Cells; Cellular biology; Cutaneous; Data; Defect; Development; ERBB2 gene; Eating; Elderly; Epithelial; Etiology; Focal Adhesions; Frequencies; Future; Genetic; Goals; Hand; Homeostasis; Human; In Vitro; Label; Laboratories; Ligands; Maintenance; Mammals; Measures; Mechanoreceptors; Mediator of activation protein; Merkel Cells; Messenger RNA; Molecular; Morphogenesis; Morphology; Mus; Organ; Pathway interactions; Physiologic pulse; Physiological; Population; Posture; Property; Proteins; Proteomics; Quality of life; Regulation; Reporter; Research Design; Rodent; Role; Sensory; Signal Pathway; Signal Transduction; Skin; Skin Aging; Source; Structure; Tactile; Tamoxifen; Testing; Texture; Touch sensation; Transgenic Mice; Transgenic Organisms; Utrophin; age related; aged; epithelial stem cell; falls; genetic approach; grasp; in vivo; keratinocyte; mouse model; mutant; nerve supply; postnatal; receptor; response; senescence; somatosensory; sound; stem cell function; stem cells; tool; transcriptome; translational study; vibration; Address; Adult; Age; Age-Months; Age-Years; Aging; Alleles; Apoptosis; Behavior; Cell Count; Cell Lineage; Cell Maintenance; Cell Survival; Cells; Cellular biology; Cutaneous; Data; Defect; Development; ERBB2 gene; Eating; Elderly; Epithelial; Etiology; Focal Adhesions; Frequencies; Future; Genetic; Goals; Hand; Homeostasis; Human; In Vitro; Label; Laboratories; Ligands; Maintenance; Mammals; Measures; Mechanoreceptors; Mediator of activation protein; Merkel Cells; Messenger RNA; Molecular; Morphogenesis; Morphology; Mus; Organ; Pathway interactions; Physiologic pulse; Physiological; Population; Posture; Property; Proteins; Proteomics; Quality of life; Regulation; Reporter; Research Design; Rodent; Role; Sensory; Signal Pathway; Signal Transduction; Skin; Skin Aging; Source; Structure; Tactile; Tamoxifen; Testing; Texture; Touch sensation; Transgenic Mice; Transgenic Organisms; Utrophin; age related; aged; epithelial stem cell; falls; genetic approach; grasp; in vivo; keratinocyte; mouse model; mutant; nerve supply; postnatal; receptor; response; senescence; somatosensory; sound; stem cell function; stem cells; tool; transcriptome; translational study; vibration

Our sense of touch enables numerous behaviors fundamental to human existence, allowing us to eat, communicate and survive. Deficits in tactile responsiveness are thought to contribute to the decline of postural stability and hand grip, and the resulting increase in falling frequency, which is a major factor determining quality of life and the ability to live independently for the elderly. In mammals, different tactile qualities (curvature, texture and vibration) are encoded by touch receptors residing in the skin with distinct physiological properties and morphological end-organs; however, the cellular and molecular mechanisms underlying this diversity are largely unknown. Furthermore, the regulation of skin stem cells that are responsible for maintaining the turnover of cellular mechanoreceptors that perceive gentle touch, such as Merkel cells, is unknown. Our laboratory previously characterized a population of epithelial stem cells that reside in epidermal touch domes in the skin, termed touch dome stem cells (TDSCs), that are responsible for maintaining the Merkel lineage during homeostasis. The long-term goal of this proposal is to define the cellular and molecular basis for TDSC maintenance of the Merkel lineage. Our preliminary data chronicles a dramatic age-related decline in Merkel cell numbers in human (40 – 90 years of age) and murine (2 – 32 months of age) skin. However, TDSC numbers remain unchanged. We confirmed that age-related loss of Merkel cells is not due to precocious exit of mature Merkel cells or defects in sensory afferent innervation but is due to diminished TDSC progenitor capacity to replenish the Merkel lineage. Leveraging this age-related deficit in TDSC progenitor capacity, we performed proteomics and mRNA profiling of TDSCs from young versus aged mouse skin and identified the focal adhesion-associated protein Utrophin (Utrn) to be dramatically downregulated in aged TDSCs. Utrn null (Utrn-/-) mice at postnatal day 20 displayed equal numbers of Merkel cells compared to Wt mice, excluding a role for Utrn in Merkel cell development. However, Merkel cell numbers were reduced by 50% in 2-month-old Utrn-/- mice providing genetic evidence for a functional role for Utrn in age-related maintenance of the Merkel lineage by TDSCs. We identified the Nrg1-Erbb2 signaling axis as a regulator of Utrn expression in mouse and human epithelial keratinocytes in vitro and TDSCs in vivo. These preliminary findings support our central hypothesis: Nrg1-Erbb2 regulation of Utrn expression is required for TDSC maintenance of Merkel cell homeostasis. To test our hypothesis, we will employ mouse models to genetically disrupt or rescue Utrn expression and assess its impact on Merkel cell homeostasis. Using in vivo lineage tracing tools and a Nrg1 conditional allele we will investigate the cellular mechanisms underlying TDSC maintenance of the Merkel lineage and upstream regulation of Nrg1 expression in the TD niche. Finally, we will interrogate the molecular mechanisms for Utrn regulation and downstream effectors of Utrn function in TDSCs. Our goal is to uncover first of its kind genetic mechanisms for stem cell regulation of the Merkel lineage.

我们的触觉使许多行为能够对人类生存为基础，使我们能够吃饭， 交流和生存。触觉反应性缺陷被认为会导致姿势下降 稳定性和手持率，以及导致的下降频率增加，这是决定的主要因素 生活质量和年龄独立生活的能力。在哺乳动物中，不同的触觉品质 （曲率，质地和振动）由居住在皮肤中的触摸受体编码，具有独特的生理 性质和形态末端；但是，这是基础的细胞和分子机制 多样性在很大程度上未知。此外，调节负责的皮肤干细胞 维持感知温和触摸（例如默克尔细胞）的细胞机理感受器的周转率是 未知。我们的实验室先前表征了驻留在表皮中的上皮干细胞的种群 皮肤中的触摸圆顶，称为触摸圆顶干细胞（TDSC），负责维持 在体内平衡期间，默克尔血统。该提议的长期目标是定义细胞和分子 TDSC维护默克尔谱系的基础。我们的初步数据记录了与年龄有关的戏剧性 人（40 - 90岁）和鼠（2 - 32个月大）的默克尔细胞数量下降。 但是，TDSC编号保持不变。我们确认与年龄相关的默克尔细胞的损失不是由于 成熟的默克尔细胞的早期出口或感觉传统神经的缺陷，但由于TDSC降低 复制默克尔血统的祖细胞能力。利用TDSC祖先的这种与年龄有关的防御 能力，我们从Young小鼠皮肤和老年人皮肤的TDSC进行了蛋白质组学和mRNA分析 鉴定出与粘剂相关的蛋白乌托蛋白（UTRN）在老年中被动态下调 TDSCS。与WT相比 小鼠，不包括UTRN在默克尔细胞发育中的作用。但是，通过 2个月大的UTRN - / - 小鼠中有50％为UTRN提供遗传证据 TDSCS维护Merkel血统。我们将NRG1-ERBB2信号轴确定为 在体外和体内TDSC中，小鼠和人上皮角质形成细胞中的UTRN表达。这些初步 研究结果支持我们的中心假设：TDSC需要NRG1-ERBB2 UTRN表达的调节 维持默克尔细胞稳态。为了检验我们的假设，我们将采用鼠标模型来基因 破坏或营救UTRN表达并评估其对默克尔细胞稳态的影响。使用体内谱系 跟踪工具和NRG1条件等位基因，我们将研究TDSC的细胞机制 维持默克尔谱系和TD小众中NRG1表达的上游调节。最后，我们会的 询问UTRN调节和UTRN功能下游效应的分子机制。 我们的目标是首先发现默克尔谱系干细胞调节的同类遗传机制。