Foxp3 isoforms and IgE-mediated UVB-induced skin inflammation expression

项目总结 紫外线B光(UVB；280-315 nm)是一种常见的环境诱因，可诱发皮肤 几种自身免疫性疾病中的炎症和红斑。紫外线是皮肤红斑的既定触发物 SLE患者，大气中UVB强度的局部尖峰与SLE中的耀斑频率相关 在该地理区域内的患者。在小鼠中，中波紫外线照射后，IgE抗体升高，以前 研究表明，皮肤反应性IgE在去除致癌物后受损的角质形成细胞方面也起着关键作用 曝光。然而，自反应性IgE在光敏反应中的作用尚未被研究。 自身免疫力。 调节性T(Treg)细胞在维持免疫系统动态平衡和调节 免疫反应。Foxp3是Treg发育和功能的主要调节因子。患者中Foxp3基因突变的研究 患有IPEX(免疫调节失调、多内分泌疾病、肠病、X连锁综合征)，导致 Tregs缺陷导致致命性自身免疫，类似于在Foxp3缺陷小鼠中观察到的疾病。而当 人类和老鼠在氨基酸序列和基因结构上都高度保守，一个不同之处是 人类FOXP3基因编码两种主要的选择性剪接异构体：一个全长版本，使用 所有10个外显子(FOXP3FL，小鼠唯一的异构体)和一个缺失外显子2的较短的异构体(FOXP3∆E2)。近期 研究表明，某些自身免疫性疾病患者的Tregs表达水平升高 ∆E2亚型与健康献血者的比较。与这一发现一致，我们发现特雷格斯来自 系统性红斑狼疮患者FOXP3FXP3∆E2亚型表达增加。 为了研究∆E2亚型在Treg功能中的作用，我们产生了一个新的带有Foxp3外显子的小鼠品系 2删除。有趣的是，我们发现foxp3dna-2小鼠出现了系统性红斑狼疮的特征，包括抗∆。 和抗核自身抗体，自发性生发中心和肾脏的数量和大小增加 4-5周龄时抗体复合体沉积。重要的是，这些小鼠表现出显著的增加 循环中的IgE，并产生针对皮肤抗原的IgE特异性自身抗体，包括角蛋白2和14。 此外，这些小鼠的皮肤中有IgE沉积，在UVB照射后显著增加。我们的 中心假说是Foxp3DE2表达的Tregs无法调节生发中心的反应和 推广免疫球蛋白E自身抗体。为了验证这一假设，我们将首先确定foxp3∆ex2表达的作用 Tregs在生发中心的功能，重点研究Tfh和Tfr细胞之间的关系。接下来，我们将评估 自身反应性IgE在UVB介导的小鼠皮肤炎症中的作用。这些研究将提供 FOXP3、∆、E2Treg功能在炎症性皮肤发生发展中的作用 疾病。

PROJECT SUMMARY Ultraviolet B light (UVB; 280-315nm) is a common environmental trigger that can induce skin inflammation and flares in several autoimmune diseases. UVB light is an established trigger for skin flares in SLE patients, and regional spikes in atmospheric UVB intensity correlate with flare frequency among SLE patients within that geographic region. In mice, IgE antibodies are elevated after UVB exposure, and previous work shows that skin-reactive IgE also plays a key role in removing damaged keratinocytes after carcinogen exposure. However, the role of self-reactive IgE has not been studied in photosensitivity reactions in autoimmunity. Regulatory T (Treg) cells play a central role in maintaining immune system homeostasis and modulating immune responses. Foxp3 is a master regulator of Treg development and function. FOXP3 mutations in patients with IPEX (Immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome), which result in a deficiency in Tregs, result in lethal autoimmunity, similar to the disease observed in Foxp3 deficient mice. While highly conserved in both amino acid sequence and gene structure, one difference between humans and mice is that the human FOXP3 gene encodes two major alternatively spliced isoforms: a full-length version that uses all 10 exons (FOXP3FL, the only isoform in mice) and a shorter isoform lacking exon 2 (FOXP3∆E2). Recent studies have shown that Tregs from patients with some autoimmune diseases express increased levels of the ∆E2 isoform compared to those from healthy donors. Consistent with this finding, we have found that Tregs from SLE patients have increased expression of the FOXP3∆E2 isoform. To study the role of the ∆E2 isoform in Treg function we generated a new mouse strain with Foxp3 exon 2 deletion. Interestingly, we found that Foxp3∆E2 mice develop hallmark features of SLE, including anti-DNA and anti-nuclear autoantibodies, increased number and size of spontaneous germinal centers and kidney deposition of antibody complexes, by 4-5 weeks of age. Importantly, these mice display a marked increase in circulating IgE and develop IgE-specific autoantibodies against skin antigens, including Keratins 2 and 14. In addition, these mice have IgE deposits in the skin, which increase dramatically following UVB irradiation. Our central hypothesis is Foxp3DE2-expressing Tregs fail to regulate germinal center responses and promote IgE autoantibodies. To test this hypothesis, we will first determine the role of Foxp3∆Ex2-expressing Tregs in germinal center function, focusing on the relationship between Tfh and Tfr cells. Next, we will assess the role of autoreactive IgE in UVB-mediated skin inflammation in these mice. These studies will provide insights into the role of Foxp3∆E2 Treg function and the development and progression of inflammatory skin disease.