IL-17C mediated mechanisms of inflammation

描述（由申请人提供）：IL-17 C是细胞因子IL-17家族的一种新的和功能上不同的成员，并通过IL-17 RE和IL-17 RA起作用，以促进上皮细胞中的先天防御并调节Th 17细胞分化。在人类银屑病组织中，IL-17 C在皮损皮肤中高度表达，并定位于角质形成细胞（KC）、内皮细胞（EC）和白细胞并对其发挥作用。我们的初步数据表明，在IL-17 C刺激后，CD 4 + T细胞衍生的IL-17 A和IL-22（Th 17和Th 22）以及EC衍生的TNF α增加。有趣的是，用IL-17 C和TNF β刺激的KC产生与IL-17 A/TNF β引起的相似的协同炎症基因反应模式（但幅度更高），并且这些基因反应模式随着IL-17 A的加入而进一步增强，表明内皮，表皮和Th 17/22细胞之间的正促炎反馈回路。在用TNFa抑制剂治疗的银屑病患者中，皮肤IL-17 C表达在皮肤改善之前迅速降低（在72小时内），并且IL-17 A和IL-22的血清水平降低，这表明IL-17 C可能充当放大Th 17/22/TNFa介导的对银屑病发病机制至关重要的炎性信号传导的新机制。为了进一步探索IL-17 C在介导银屑病样炎症中的重要性，我们对小鼠进行基因工程改造，使其在KC中过表达IL-17 C。鼠皮肤发育未受累组织的界限清楚的区域，其特征在于在没有表皮增生的情况下增加的血管生成和适度的白细胞浸润，以及受累皮肤的邻近区域，其表现出强烈的表皮增生、增加的白细胞浸润和TNF α、IL-17 A和IL-22的增加;提示IL-17 C与其它促炎信号结合时导致银屑病样皮肤皮炎的发展。综上所述，这些观察结果表明，IL-17 C是IL-17家族的快速反应成员，并且它协同激活KC、内皮细胞和Th 17/22细胞之间的促炎反馈回路，并且在银屑病中可能是关键的。 我们将使用这种创新的新小鼠模型，基因敲除方法，cre-lox技术和抗体靶向策略，以及体外细胞共培养，SiRNA，细胞信号传导和生物测定方法来测试以下假设：IL-17 C结合靶细胞上的IL-17 RE/A上调TNF β（EC）和IL-17/IL-22（Th 17/22），它们与IL-17 RE/A协同联合收割机结合。17 C诱导KC活化和表皮增生。我们打算确定IL-17 C作为启动和维持慢性皮肤炎症所需的关键早期上游促炎细胞因子，并确定受影响的关键细胞靶点。 通过IL-17 C以及用于指导KC、EC和Th 17/22细胞应答的潜在机制，这些应答转化为银屑病中持续的炎症和棘皮症。这项工作将为将来探索靶向IL-17 C或IL-17 RE治疗银屑病的治疗开发潜力的工作提供基础和理由。

DESCRIPTION (provided by applicant): IL-17C is a novel and functionally distinct member of the IL-17 family of cytokines and acts through IL- 17RE and IL-17RA to promote innate defense in epithelial cells and regulate Th17 cell differentiation. In human psoriasis tissue, IL-17C is highly expressed in lesional skin and localizes to and exerts effects upon keratinocytes (KCs), endothelial cell (ECs) and leukocytes. Our preliminary data demonstrates increases in CD4+ T cell-derived IL-17A and IL-22 (Th17 and Th22) and EC-derived TNFa following IL-17C stimulation. Interestingly, KCs stimulated with IL-17C and TNF� produce similar synergistic inflammatory gene response patterns as those elicited by IL-17A/TNF� (but at higher magnitudes) and these gene response patterns are further enhanced with the addition of IL-17A, indicating a positive pro-inflammatory feedback loop between the endothelium, epidermis and Th17/22 cells. In psoriasis patients treated with TNFa inhibitors, cutaneous IL-17C expression decreases rapidly (within 72h) prior to skin improvement and decreases in serum levels of IL-17A and IL-22 suggesting IL-17C may serve as a novel mechanism for amplifying Th17/22/TNFa mediated inflammatory signaling critical for psoriasis pathogenesis. To further explore the importance of IL-17C in mediating psoriasiform inflammation, we genetically engineered mice to overexpress IL-17C in KCs. Murine skin develops well demarcated areas of uninvolved tissue, characterized by increased angiogenesis and modest leukocyte infiltration in the absence of epidermal hyperplasia as well as adjacent areas of involved skin that exhibit robust epidermal hyperplasia, increased leukocyte infiltration and increases in TNFa, IL-17A, and IL-22; suggesting that IL-17C, when coupled with other pro-inflammatory signals, leads to the development of psoriasiform skin dermatitis. Taken together, these observations suggest that IL-17C is a rapidly responsive member of the IL-17 family and that it synergistically activates a proinflammatory feedback loop between KCs, the endothelium and Th17/22 cells and may be critical in psoriasis. We will use this innovative new mouse model, genetic knockout approaches, cre-lox technologies and antibody targeting strategies coupled with in vitro cell co-culture, SiRNA, cell signaling and bioassay approaches to test the hypothesis that: IL-17C binding IL-17RE/A on target cells up regulates TNF� (EC) and IL-17/IL-22 (Th17/22) that combine synergistically with IL-17C to induce KC activation and epidermal hyperplasia. We intend to identify IL-17C as a critical early upstream proinflammatory cytokine required for initiating and sustaining chronic skin inflammation, and identify the key cellular targets affected by IL-17C as well as the potential mechanism(s) used to direct KC, EC and Th17/22 cell responses that translate to sustaining inflammation and acanthosis in psoriasis. This work will provide the basis and justification for future work exploring the potential of targeting IL-17C or IL-17RE for therapeutic development for the treatment of psoriasis.