Trim32 Regulation of Piasy in Skin Homeostasis

描述（由申请人提供）：银屑病中存在恶性循环，通过角质形成细胞（过度增殖、角化不全）和免疫细胞（浸润和活化）的改变破坏表皮稳态。虽然众所周知，不受控制的角质形成细胞增殖主要由来自免疫细胞的促炎细胞因子驱动，但对角质形成细胞在免疫细胞的募集和活化中的功能作用知之甚少。我们发现Trim 32（一种E3泛素连接酶）及其底物Piasy（一种E3 SUMO连接酶）与银屑病之间存在有趣的联系。与非病变对照表皮相比，银屑病组织样品中Trim 32升高。Trim 32负性调节促凋亡Piasy蛋白，其是参与银屑病发病机制的NF-κ B、STAT和SMAD转录因子的阻遏物。Piasy基因位于染色体19 p13上的PSORS 6易感性位点，尽管其意义仍有待确定。我们发现Trim 32激活和Piasy抑制角质形成细胞产生CCL 20，CCL 20是一种在银屑病病变中增加的趋化因子，是树突状细胞和Th 17淋巴细胞向皮肤募集的主要因素。通过TNF α和IL 17细胞因子的CCL 20诱导是通过NF-κ B的活化介导的。这些发现使我们假设Trim 32和Piasy是角质形成细胞过度产生CCL 20和Th 17激活的正反馈回路的一部分，这有助于银屑病的周期。最初的证据表明，Trim 32不仅仅是表皮增生的一般标志物，因为它在银屑病中的升高（被认为是Th 17疾病）不被特应性皮炎（被认为是Th 2细胞疾病）所共有，并且因为角质形成细胞中CCL 20的上调响应于Th 17而不是Th 1或Th 2细胞因子。我们拟通过以下目的来确定Trim 32和Piasy在银屑病中的作用：1）确定Trim 32和Piasy调节角质形成细胞对Th 17细胞因子应答产生CCL 20的分子途径，特别是通过NF-κ B途径，并评估Trim 32和Piasy对CD 11 c+树突状细胞和Th 17细胞的真皮募集的影响; 2）使用体外和体内方法探索Trim 32和Piasy在响应于Th 17活化的角质形成细胞存活和表皮棘皮病中的功能作用，并确定Trim 32 KO和Piasy KO对两种银屑病样皮炎小鼠模型中表型严重性的影响;（3）研究Trim 32和Piasy在银屑病和特应性皮炎中对CCL 20表达、炎症反应和角质形成细胞凋亡的影响。最终，这些研究可能会影响我们对银屑病与特应性皮炎不同的分子机制的理解，并导致银屑病患者治疗策略的合理改进。公共卫生相关性：牛皮癣是一种皮肤病，其中皮肤细胞失去了它们的生长和死亡率之间的适当平衡，某些免疫系统细胞过度活跃。我们已经发现，酶“Trim 32”在银屑病中过度活跃，导致蛋白质Piasy的损失，Piasy是某些基因的主要抑制剂，这些基因在人类银屑病中活跃，并且可以在小鼠中引起银屑病样症状，导致蛋白质的产生，吸引更多的免疫细胞到皮肤上，使症状恶化。了解Trim 32和Piasy如何控制皮肤细胞存活和皮肤炎症，有望为治疗银屑病和其他人类皮肤疾病以及身体其他器官的炎症性疾病提供新的方法。

DESCRIPTION (provided by applicant): There is a vicious circle in psoriasis that disrupts epidermal homeostasis through alterations in keratinocytes (hyperproliferation, parakeratosis) and immunocytes (infiltration and activation). While it is well known that uncontrolled keratinocyte proliferation is largely driven by pro-inflammatory cytokines from the immunocytes, the functional role of keratinocytes in the recruitment and activation of immunocytes is poorly understood. We have discovered intriguing links between Trim32 (an E3 ubiquitin ligase), its substrate Piasy (an E3 SUMO ligase), and psoriasis. Trim32 is elevated in psoriasis tissue samples compared to non-lesional control epidermis. Trim32 negatively regulates the pro-apoptotic Piasy protein, a repressor of NF-kB, STAT, and SMAD transcription factors that have been implicated in the pathogenesis of psoriasis. The Piasy gene resides in the PSORS6 susceptibility locus on chromosome 19p13, although the significance of this remains to be determined. We have found that Trim32 activates and Piasy inhibits keratinocyte production of CCL20, a chemokine increased in psoriatic lesions that is a major factor in recruitment of dendritic cells and Th17 lymphocytes to the skin. The CCL20 induction by TNFa and IL17 cytokines is mediated through the activation of NF-kB. These findings lead us to hypothesize that Trim32 and Piasy are part of a positive feedback loop of CCL20 overproduction by keratinocytes and Th17 activation that contributes to the cycle of psoriasis. Initial evidence suggests that Trim32 is not simply a general marker of epidermal hyperplasia because its elevation in psoriasis, recognized as a Th17 disease, is not shared by atopic dermatitis, recognized as a Th2 cell disease, and because upregulation of CCL20 in keratinocytes responds to Th17 but not Th1 or Th2 cytokines. We propose to define the role of Trim32 and Piasy in psoriasis according to the following aims: 1) determine molecular pathways of Trim32 and Piasy regulation of CCL20 production in keratinocytes in response to Th17 cytokines, in particular through the NF-kB pathway, and evaluate the effects of Trim32 and Piasy on the dermal recruitment of CD11c+ dendritic cells and Th17 cells; 2) explore the functional role of Trim32 and Piasy in keratinocyte survival and epidermal acanthosis in response to Th17 activation, using in vitro and in vivo approaches, and determine the impact of Trim32 KO and Piasy KO on the severity of phenotypes in two mouse models of psoriasiform dermatitis; and 3) evaluate the role of Trim32 and Piasy in CCL20 expression, inflammation and keratinocyte apoptosis in psoriasis and atopic dermatitis. Ultimately, these studies may impact our understanding of the molecular mechanisms of psoriasis as distinct from atopic dermatitis and lead to rational improvement of treatment strategies for psoriasis patients. PUBLIC HEALTH RELEVANCE: Psoriasis is a skin disease in which skin cells lose the proper balance between their growth and death rates, and certain immune system cells are over-active. We have found that the enzyme "Trim32" is overly active in psoriasis, causing loss of the protein Piasy, a major inhibitor of certain genes that are active in human psoriasis and that can cause psoriasis-like symptoms in mice, leading to the production of proteins that attract more immune cells to the skin, making the symptoms worse. Understanding how Trim32 and Piasy control skin cell survival and skin inflammation promises new ways to treat psoriasis and other human diseases of the skin, as well as inflammatory diseases in other organs of the body.