Genetic predisposition and the role of myeloid cells in the susceptibility to mycobacterial infections in human

传染病仍然是世界范围内毁灭性的公共卫生负担。威胁生命的细菌疾病可由单基因先天性免疫错误(IEI)引起。孟德尔分枝杆菌病(MSMD)是一组IEI，其特征是在其他健康的患者中由弱毒力分枝杆菌引起的严重感染。MSMD患者也容易感染肺结核和其他由巨噬细胞内病原体引起的疾病。在已知的19个引起MSMD的基因中，有18个基因控制着对巨噬细胞激活因子-干扰素-g的诱导和/或反应。我们推测这些患者患有新的单基因IEI，可能影响了干扰素-g介导的免疫。该项目利用了1,200名MSMD患者的独特集合。然而，许多MSMD患者的遗传病因仍不清楚，有可用的完整外显子组测序(WES)数据。我们将在这些患者中寻找新的IEI，并验证它们的致病作用，具体目标如下：i)招募MSMD患者(全球)和全基因组(GW)计算方法以选择新的MSMD候选基因；ii)在分子和细胞水平验证新的MSMD致病基因和突变变体的产物，以及它们与已知的MSMD遗传病因的联系；iii)利用IPSC的体外造血分化研究MSMD致病基因和变体的骨髓生成。我们的项目得到了强大的初步数据的支持，我们发现了四种令人兴奋的候选病因：常染色体隐性IRF1、肿瘤坏死因子和CCR2缺陷；以及一种X连锁隐性MCTS1缺陷。虽然基于小鼠模型，IRF1、CCR2和TNF缺陷被预测为MSMD的基础，但MCTS1缺陷的发现最令人惊讶。这四种疾病会影响髓系血统。我们还已经从一名IRF1缺陷患者身上培养出了IPSCs。这三个小组的独特专业知识将通过深入描述确诊为MSMD的患者自然发生的罕见生殖系突变，协同解决造血细胞(特别是髓细胞)和MSMD的问题。这一将WES分析与包括IPSC技术在内的深入功能研究相结合的综合计划是可以实现的，在医学、遗传学、免疫学和感染领域具有很高的创新性。该项目将为分枝杆菌疾病(包括结核病)的发病机制提供新的生物学见解，澄清毁灭性的医学问题。此外，临床意义将不仅在分子诊断、遗传咨询和预后方面帮助患者及其家人，还将在治疗方面帮助患者，因为重组干扰素-g可以治疗产生干扰素-g的患者。

Infectious diseases remain a devastating public health burden worldwide. Life-threatening bacterial diseases can result from single-gene inborn errors of immunity (IEI). Mendelian susceptibility to mycobacterial disease (MSMD) is a group of IEI characterized by severe infections caused by weakly virulent mycobacteria in otherwise healthy patients. MSMD patients are also vulnerable to tuberculosis and other diseases caused by intra-macrophagic pathogens. Eighteen of the 19 known MSMD-causing genes control the induction and/or the response to interferon gamma (IFN-g), which is the macrophage-activating factor. We hypothesize that these patients suffer from novel single-gene IEI, probably affecting IFN-g mediated immunity. This project capitalizes on a unique collection of 1,200 patients with MSMD. However, the genetic etiology of many MSMD patients remains unknown, with available whole exome sequencing (WES) data. We will search for novel IEI in these patients and validate their disease-causing effects following three specific aims: i) recruitment of MSMD patients (worldwide) and genome-wide (GW) computational approaches to select novel MSMD-causing candidate genes, ii) validation at the molecular and cellular levels of the products of novel MSMD-causing genes and mutant variants, and their connection with those of known genetic etiologies of MSMD, iii) study of myelopoiesis of MSMD-causing genes and variants using in vitro hematopoietic differentiation of iPSCs. Our project is supported by strong preliminary data, with our identification of four exciting candidate etiologies; with autosomal recessive IRF1, TNF, and CCR2 deficiencies; and one X-linked recessive MCTS1 deficiency. While IRF1, CCR2 and TNF deficiencies were predicted to underlie MSMD based on the mouse model, the discovery of MCTS1 deficiency is most surprising. The four disorders affect the myeloid lineage. We have also already generated iPSCs from one IRF1-deficient patient. The unique expertise of the three groups will synergistically tackle the problems of hematopoietic cells (in particular myeloid cells) and MSMD through the in-depth characterization of rare germline mutations occurring in natura in patients with MSMD diagnosis. This integrated program combining WES analyses with in-depth functional studies including by iPSC technology is achievable and highly innovative in the fields of medicine, genetics, immunology, and infection. This project will provide new biological insights into the pathogenesis of mycobacterial diseases (including tuberculosis) clarifying devastating medical problems. Moreover, the clinical implications will help the patients and their families not only in terms of molecular diagnosis, genetic counseling, and prognosis, but also in terms of treatment, as patients with impaired production of IFN-g can be treated with recombinant IFN-g.