The role of SERPINB1 in T cell function and its contribution to human diseases

项目摘要 原发性免疫缺陷症（primaryimmunodeficiencies，PID）是一组由先天性免疫缺陷引起的单基因疾病 (IEI)会导致严重感染、自身免疫和癌症。IEI的遗传学和免疫学研究 有助于了解人体免疫机制，并管理和治疗PID患者。他们的 这项研究对于了解更多与遗传变异相关的常见疾病也很重要， 基因.然而，尽管从基础科学和临床研究PID的相关性和重要性， 从遗传学的角度来看，一半的PID患者缺乏基因诊断。通过研究一个PID未知的病人， 遗传病因赋予严重的分枝杆菌疾病的易感性，我们确定了一个无义突变 在SERPINB 1中。我们综合运用群体遗传学、生物化学和分子生物学， 这是迄今为止描述的第一例SERPINB 1完全缺陷的病例。SERPINB 1是细胞内丝氨酸 蛋白酶自杀抑制剂。其在小鼠中的缺失导致不受控制的细胞内蛋白酶活性，导致 中性粒细胞死亡和随后的中性粒细胞减少。有趣的是，我们的病人没有任何中性粒细胞 异常，但相反，我们深入的免疫学特征显示， 活化T细胞和CD 4+记忆T细胞。我们的研究结果表明SERPINB 1具有以前未知的 在T细胞和抗分枝杆菌免疫中的功能。我们的数据还表明，SERPINB 1协调了一个 T细胞活化和存活所必需的细胞内蛋白酶介导的途径。根据我们的调查结果， 本申请将检验SERPINB 1对人T细胞活化至关重要的假设，并通过控制 细胞内蛋白酶活性，对人类疾病的影响。利用这个病人提供的独特机会 为了理解人SERPINB 1的功能，我们提出了三种互补的方法。目标1： 将表征SERPINB 1缺陷对T细胞活化和CD 4 + T细胞的免疫学后果。 分化我们还将研究SERPINB 1缺陷在T细胞中的转录后果。有了这个， 我们将揭示SERPINB 1在人类T细胞中的一个以前未知的功能。在目标2中，我们将确定和 表征由SERPINB 1在T细胞中协调的途径。SERPINB 1的缺失释放了 细胞内蛋白酶的作用。这种罕见的PID机制将允许这些蛋白酶的化学抑制 用于治疗目的。此外，表征SERPINB 1依赖性抗分枝杆菌机制 将导致在缺乏遗传诊断的患者中识别其途径中的额外IEI。在目标3中， 将进行全表型关联研究（pheWAS），以确定 SERPINB 1通路和其他人类疾病。这种反向遗传的方法将扩大我们将 从一种罕见疾病的研究中学习，使更广泛的患者群体受益。我们的研究计划- 为理解SERPINB 1介导的免疫、PID、抗- 分枝杆菌免疫，以及SERPINB 1途径对人类疾病的贡献。

PROJECT SUMMARY Primary immunodeficiencies (PIDs) are a group of monogenic diseases caused by inborn errors of immunity (IEI) that confer risk of severe infection, autoimmunity, and cancer. The genetic and immunological study of IEI is instrumental to understand mechanisms of human immunity and to manage and treat patients with PIDs. Their study is also important to understand more common diseases associated with genetic variants in the same genes. However, despite the relevance and importance of studying PIDs from the basic science and clinical points of view, half of the PID patients lack a genetic diagnosis. By studying a patient with a PID of unknown genetic etiology that confers susceptibility to severe mycobacterial disease, we identified a nonsense mutation in SERPINB1. Using a combination of population genetics, biochemistry, and molecular biology, we showed that this is the first case of SERPINB1 complete deficiency ever described. SERPINB1 is an intracellular serine protease suicide inhibitor. Its absence in mice causes uncontrolled intracellular protease activity, leading to neutrophil death and subsequent neutropenia. Interestingly, our patient does not display any neutrophil abnormality, but instead, our in-depth immunological characterization showed a reduction in the frequency of activated T cells and CD4+ memory T cells. Our findings suggest that SERPINB1 has a previously unknown function in T cells and antimycobacterial immunity. Our data also indicates that SERPINB1 orchestrates an intracellular protease-mediated pathway essential for T cell activation and survival. Given our findings, this application will test the hypothesis that SERPINB1 is critical for human T cell activation and, by controlling intracellular protease activity, to human diseases. Capitalizing on the unique opportunity that this patient offers to understand the function of human SERPINB1, we propose three complementary approaches. In Aim 1, we will characterize the immunological consequences of SERPINB1 deficiency on T cell activation and CD4+ T cell differentiation. We will also study the transcriptional consequences of SERPINB1 deficiency in T cells. With this, we will uncover a previously unknown function of SERPINB1 in human T cells. In Aim 2, we will identify and characterize the pathways orchestrated by SERPINB1 in T cells. The absence of SERPINB1 unleashes the action of intracellular proteases. This rare mechanism of PID will allow for chemical inhibition of these proteases for therapeutic purposes. Furthermore, characterizing the SERPINB1-dependent antimycobacterial mechanisms will lead to the identification of additional IEI in its pathway in patients lacking a genetic diagnosis. In Aim 3, we will perform phenome-wide association studies (pheWAS) to identify associations between genetic variants in the SERPINB1 pathway and additional human diseases. This reverse genetic approach will expand what we will learn from the study of a rare disease to benefit a broader group of patients. Our proposed research has far- reaching clinical and biological implications for understanding SERPINB1 mediated immunity, PIDs, anti- mycobacterial immunity, and the contribution of the SERPINB1 pathway to human disease.