ROQUIN基因家族的罕见突变在罕见免疫炎症及自身免疫疾病发生发展中的作用

Hemophagocytic lymphohistiocytosis (HLH) is a rare, potentially life threatening systemic autoinflammatory syndrome that is either associated with genetic abnormalities resulting in defective natural killer (NK)/cytotoxic T-cell function or acquired in the setting of conditions, such as infections, autoimmunity, or malignancy. Its actual prevalence may be higher than reported as it tends to be underdiagnosed due to heterogeneity in symptoms, particularly when in the context of associated underlying conditions. Current treatment involves prompt therapy with immunosuppression combined with chemotherapy. However, half of patients with HLH either fail to respond adequately or relapse before hematopoietic cell transplantation indicating a clear need for new treatments..Systemic lupus erythematosus (SLE) is considered the prototypical systemic autoimmune disease and its incidence is particularly high in China. SLE has a strong genetic component. Disease manifestations of SLE are highly heterogeneous. Dissecting the heterogeneity in pathogenesis and stratification of patients according to affected pathways will illuminate targeted therapies and improve the success of clinical trials. There is an increasing number of genes found to cause monogenic human SLE. Nevertheless SLE mostly follows complex, non-Mendelian patterns of inheritance. It is unclear whether it is the combination of a few rare, potent variants or tens to hundreds of common, mild variants that contribute to SLE; it is reasonable to expect that it will be a combination of both. No matter what the genetics are, the identification of any causative allele will be extremely useful to dissect disease mechanisms and identify superior biomarkers and pathway targeted therapies..We have now sequenced the whole exomes or genomes of patients with immune disorders and discovered 27 novel and rare missense allelic variants in the genes encoding the ROQUIN family fambers RC3H1 (11 variants) and RC3H2 (8 variants) and in the ZC3H12A gene encoding the ROQUIN-interacting protein REGNASE-1 (8 variants) in patients presenting with lupus or HLH. These mutations are found in different domains of the proteins. A mutation in mouse Roquin was sufficient to cause a lupus-like disease associated with high cytokine production, and can also cause a tumour closely resembling angioimmunoblastic T cell lymphoma. In both of these conditions, follicular helper T cells and cytotoxic T cells are dysregulated. To date, there are no reports of mutations in ROQUIN and its immediate partner proteins causing human immune diseases..In this proposal, we will investigate whether variants in the ROQUIN family can be identified in the Chinese population, test disease causation of variants identified so far, and identify the mechanisms by which these variants cause immune disease. This will be achieved through the generation of cell and mouse lines bearing some of these ROQUIN family variants using CRISPR/Cas9..Overall hypothesis: Novel or rare mutations in the ROQUIN family cause systemic autoimmune and autoinflammatory syndromes through aberrant stabilization of mRNA transcripts encoding pro-inflammatory cytokines and enhance NF-kB signaling. Patients with mutations in these genes may respond to cytokine-targeted therapies including JAK inhibitors.

嗜血细胞性淋巴组织细胞增生症（HLH）是一种罕见的，危及生命的全身性自身炎症综合征。系统性红斑狼疮（SLE）是系统性自身免疫疾病，发病率高，与遗传相关并高度异质。目前尚不清楚一些罕见的变异是否导致这两种疾病。鉴定致病等位基因对于分析疾病机制和精准治疗至关重要。通过测序狼疮或HLH患者的外显子组或基因组，我们在编码ROQUIN家族3个基因中发现了27个新的罕见错义等位基因突变。小鼠Roquin突变会引起狼疮样疾病或T细胞淋巴瘤。迄今还没有关于引起人类免疫性疾病的ROQUIN及其伴侣蛋白突变的报道。我们认为ROQUIN家族中新的罕见突变通过编码促炎细胞因子的mRNA转录物并增强NF-kB信号传导引起疾病。这些患者可能会对包括JAK抑制剂在内的靶向治疗产生应答。我们将调查中国人群中的ROQUIN家族中突变并通过使用CRISPR / Cas9产生带有ROQUIN家族突变的细胞和小鼠来研究发病机制。

嗜血细胞性淋巴组织细胞增生症（HLH）是一种罕见的全身性自身炎症综合征。通过对HLH患者的外显子组测序，我们发现一例患者携带ROQUIN-1基因罕见无义突变R688*，该突变使ROQUIN-1功能缺陷，ROQUIN-1基因缺陷的狼疮小鼠模型表现出明显的高细胞因子血症，免疫失调，同时ROQUIN-1中R688*无义突变导致其与P小体共定位受损，基因ICOS的mRNA降解过程被突变型ROQUIN-1所阻断。此外我们在HLH患者中也发现了多个Regnase-1的罕见突变位点，双荧光报告预实验提示Regnase-1突变位点P346H，V191M和R293H在不同程度上影响NFkB通路。我们也在HLH患者中发现了SOCS1的罕见突变T53A，该突变影响其蛋白的稳定性，同时，该突变促进IFN-a和IFN-γ诱导的JAKS-STAT1通路的激活。这些突变的发现及对其机制的研究有助于找到治疗疾病的新的靶点通路。