EphA/Ephrin-A signaling in epidermal differentiation and disease

表皮分化和疾病中的 EphA/Ephrin-A 信号传导

• 批准号: 8439076
• 负责人: Spiro Getsios
• 金额: $ 34.2万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-07 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8439076
• 关键词: 3-Dimensional; Adult; Affinity; Architecture; Atopic Dermatitis; Binding; Biology; Cell Communication; Cell Surface Proteins; Cell surface; Cells; Chimera organism; Collaborations; Complex; Cues; Cytoplasmic Tail; Deletion Mutation; Development; Disease; Down-Regulation; Elements; Embryonic Development; Eph Family Receptors; EphA Receptors; Ephrin-A1; Ephrins; Epidermal Growth Factor Receptor; Epidermis; Epithelial; Event; Exhibits; Extracellular Domain; Family; Flax; Gatekeeping; Gene Delivery; Gene Silencing; Genes; Genetic; Goals; Homeostasis; Human; Individual; Inflammatory; Lead; Ligand Binding; Ligands; Link; Lipids; Mediating; Modeling; Molecular; Molecular Target; Morphogenesis; Mutagenesis; Mutate; Mutation; Pathway interactions; Pattern; Phosphoric Monoester Hydrolases; Physiology; Play; Process; Proteomics; Psoriasis; Receptor Activation; Receptor Cell; Receptor Protein-Tyrosine Kinases; Regulation; Relative (related person); Research; Role; Serum Response Factor; Signal Pathway; Signal Transduction; Skin; Staging; Sterility; Stratum Basale; Surface; Testing; Therapeutic; Tissues; Undifferentiated; Work; design; extracellular; innovation; insight; integrin-linked kinase; keratinization; keratinocyte; keratinocyte differentiation; notch protein; novel; prevent; protein complex; receptor; reconstitution; response; skin disorder; species difference; success; tumor growth; tumor progression

DESCRIPTION (provided by applicant): Epidermal differentiation is essential for survival and impaired in common skin diseases, including psoriasis. Keratinocytes interact and communicate with their neighbors via cell surface proteins; this helps determine whether epidermal cells divide in the basal layer, differentiate in the suprabasal layers and die in the cornified layer. Te long-term goal of this proposal is to define the role of a cell-cell communication pathway, termed the EphA/ephrin-A signaling axis, in epidermal [differentiation] and disease. This large family of receptor tyrosine kinases plays a key role in embryonic development and cancer progression but has not been thoroughly investigated in normal adult epithelial tissues, especially the skin. Species differences in the character and molecular composition of EphA receptors in the epidermis necessitate the application of experimental approaches that take advantage of human cells. Consequently, an organotypic raft model of human epidermis that has been adapted for long-term gene silencing and reconstitution will be employed to define the reciprocal roles for EphA1 and EphA2 in epidermal differentiation and morphogenesis. We will test the innovative hypothesis that EphA1 and EphA2 exhibit discrete functions in keratinocyte differentiation that are controlled by their responses to ephrin ligand binding. In the first aim, the mechanism(s) by which EphA2 maintains keratinocytes in an undifferentiated state until this receptor is engaged and downregulated by ephrin-A1 will be elucidated. The importance of the EphA2 cytoplasmic domain in inhibiting keratinocyte differentiation [by interacting with SHIP2, a modulator of the EGFR signaling pathway,] will be determined using genetic approaches that remove key signaling elements within this region. The response of EphA2 to ligand binding will be defined using gene mutagenesis approaches [that focus on the downstream activation of Notch signaling to promote differentiation.] The second aim will test the novel hypothesis that EphA1 promotes keratinocyte differentiation in response to ephrin-A1 binding only after EphA2 is lost from the cell surface. Mutating and replacing the extracellular and cytoplasmic subdomains of EphA1 with EphA2 sequences will reveal the key signaling elements that trigger keratinocyte differentiation, focusing on the ability of the EphA1 SAM domain to regulate the integrin-linked kinase-RhoA-[serum response factor] pathway. [The translational potential of the proposal is strengthened by the ability to harness the epidermal EphA/ephrin-A axis in inflammatory skin conditions where their relative expression changes and keratinocyte differentiation is impaired.] Important interactions with local (Northwestern U.-Skin Disease Research Center, Robert M. Lavker; [Northwestern U.-Proteomics Core, Dhaval Nanavati]) and outside (Bing-Cheng Wang, Case Western Reserve; [G.-Paolo Dotto; Harvard; Lina Dagnino; Western U.]) groups studying epithelial biology and Eph/ephrin signaling enhance the likelihood of success and impact of the proposal. PUBLIC HEALTH RELEVANCE: Information from this project will lead to a better understanding of how a cell-cell communication pathway, termed the EphA/ephrin-A signaling axis, governs the differentiation of keratinocytes in [the human epidermis. Insight gained from our studies on the reciprocal roles of EphA1 and EphA2 in keratinocyte signaling and differentiation will lead to the development of novel treatments for inflammatory skin diseases where their expression is altered, such as psoriasis.]

描述（由申请人提供）：表皮分化对于生存至关重要，并且在常见皮肤病（包括牛皮癣）中受到损害。角质形成细胞通过细胞表面蛋白与其邻居相互作用和交流；这有助于确定表皮细胞是否在基底层分裂、在基底上层分化并在角质层死亡。该提案的长期目标是定义细胞间通讯途径（称为 EphA/ephrin-A 信号轴）在表皮[分化]和疾病中的作用。这一受体酪氨酸激酶大家族在胚胎发育和癌症进展中发挥着关键作用，但尚未在正常成人上皮组织（尤其是皮肤）中进行彻底研究。表皮 EphA 受体的特征和分子组成存在物种差异，因此需要应用利用人类细胞的实验方法。因此，适用于长期基因沉默和重建的人类表皮器官筏模型将用于定义 EphA1 和 EphA2 在表皮分化和形态发生中的相互作用。我们将测试这一创新假设，即 EphA1 和 EphA2 在角质形成细胞分化中表现出离散的功能，这些功能由它们对肝配蛋白配体结合的反应控制。第一个目标是阐明 EphA2 将角质形成细胞维持在未分化状态直至该受体被 ephrin-A1 参与并下调的机制。 EphA2 胞质结构域在抑制角质形成细胞分化中的重要性（通过与 EGFR 信号通路调节剂 SHIP2 相互作用）将通过去除该区域内关键信号元件的遗传方法来确定。 EphA2 对配体结合的反应将使用基因诱变方法来定义（专注于 Notch 信号的下游激活以促进分化）。第二个目标将测试新的假设，即仅在 EphA2 从细胞表面丢失后，EphA1 才会响应肝配蛋白 A1 结合而促进角质形成细胞分化。用 EphA2 序列突变和替换 EphA1 的细胞外和细胞质子结构域将揭示触发角质形成细胞分化的关键信号元件，重点关注 EphA1 SAM 结构域调节整合素连接的激酶-RhoA-[血清反应因子]途径的能力。 [该提案的转化潜力通过在炎症性皮肤状况下利用表皮 EphA/ephrin-A 轴的能力得到加强，在炎症性皮肤状况下，表皮 EphA/ephrin-A 轴的相对表达变化和角质形成细胞分化受到损害。] 与本地（西北大学皮肤病研究中心，Robert M. Lavker；[西北大学蛋白质组学核心，Dhaval Nanavati]）和外部（Bing-Cheng）的重要相互作用 王，凯斯西储； [G.-保罗·多托；哈佛；丽娜·达格尼诺；西方大学]）研究上皮生物学和 Eph/ephrin 信号传导的小组增强了该提案成功的可能性和影响。 公共健康相关性：该项目的信息将有助于更好地理解细胞间通讯途径（称为 EphA/ephrin-A 信号轴）如何控制人类表皮中角质形成细胞的分化。我们从 EphA1 和 EphA2 在角质形成细胞信号传导和分化中相互作用的研究中获得的见解，将有助于开发出针对其表达发生改变的炎症性皮肤病（例如牛皮癣）的新疗法。]