K63-Ubiquitin-mediated cell signal regulation in epidermis

摘要 表皮及其附属物构成哺乳动物健康所必需的最外层皮肤屏障， 生存表皮细胞中涉及NF-κB、AP 1和c-Myc基因调控因子的细胞信号转导失调 会导致局部和全身性疾病以及癌症。然而，直接针对这些核心 转录因子已经被证明在技术上具有挑战性，禁止有意义的临床翻译。我们 长期目标是探索K63-Ub介导的信号如何汇聚于基因调控 并且可以合理地靶向治疗炎性和肿瘤性皮肤病。为此，我们 最近的努力集中在表征CYLD的新功能上，CYLD是一种K63-Ub蛋白酶， 这种功能与免疫性疾病、不育症以及良性和恶性肿瘤有关。虽然突变 人类的Cyld导致Cyld综合征，其特征在于广泛和复发的表皮和 附件肿瘤，了解CYLD的完整作用是由于缺乏临床相关的 疾病模型为了揭示新的疾病机制，我们建立了一个小鼠模型， 人Cyldm综合征的遗传和表型特征。使用这种动物模型，我们已经鉴定了c-Myc 作为一种新的CYLD底物，UBE 2N作为c-Myc和雄激素信号传导的上游调节剂，除了作为一种新的CYLD底物外， CYLD在NF-κB和AP 1通路调节中的作用。这些发现突出了 CYLD和Cyldm皮肤模型的实用性，以增加我们对新疾病机制的理解。 这项研究是基于这样的假设设计的，即在上皮细胞中无对抗的UBE 2N功能 促进炎症和c-Myc依赖性皮肤缺陷。我们提出了三个具体目标：1）定义 c-Myc在Cyldm皮肤中的作用; 2）确定K63-Ub介导c-Myc的分子机制 3）确定UBE 2N在表皮增殖和肿瘤发生中的功能。我们将 利用小鼠和人类皮肤组织模型，以及基因编辑的尖端技术， 转录组和蛋白质相互作用组分析。这些研究的完成将揭示新的分子 表皮形态发生的机制，并提供治疗皮肤炎症和癌症的见解。

ABSTRACT Epidermis and its appendages constitute the outermost skin barrier essential for mammalian health and survival. Dysregulation of cell signaling in epidermal cells involving NF-κB, AP1, and c-Myc gene regulators can lead to local and systemic disorders, as well as cancer. Nevertheless, direct targeting of these core transcription factors has been proven technically challenging, prohibiting a meaningful clinical translation. Our long-term objective is to explore how K63-Ubiquitin (K63-Ub)-mediated signals converge on gene regulation and can be rationally targeted for therapy of inflammatory and neoplastic skin disorders. Towards this end, our recent efforts are focused on characterizing novel functions of CYLD, a K63-Ub protease whose loss-of- function is linked to immunological diseases, infertility, and benign and malignant neoplasms. While mutant Cyld in humans leads to Cyldm-syndrome characterized by widespread and recurrent epidermal and appendage tumors, understanding the complete role of CYLD is hampered by the lack of a clinically relevant disease model. To uncover novel disease mechanisms we have generated a mouse model that recapitulates genetic and phenotypic features of human Cyldm-syndrome. Using this animal model, we have identified c-Myc as a new CYLD substrate, UBE2N as an upstream regulator of c-Myc and androgen signaling, in addition to a role of CYLD in the regulation of the NF-κB and AP1 pathways. These findings highlight the broad impact of CYLD and the utility of the Cyldm skin model for increasing our understanding of novel disease mechanisms. This study is designed based on the hypothesis that unopposed UBE2N function in epithelial cells promotes inflammation and c-Myc-dependent skin defects. We propose three specific aims: 1) to define the role of c-Myc in Cyldm skin; 2) to determine the molecular mechanisms underlying K63-Ub-mediated c-Myc activation; and 3) to determine the functions of UBE2N in epidermal proliferation and tumorigenesis. We will utilize mouse and human skin tissue models, as well as cutting-edge technologies for gene editing, transcriptome and protein interactome analyses. Completion of these studies will reveal novel molecular mechanisms of epidermal morphogenesis and provide therapeutic insights for skin inflammation and cancer.