Characterization of a novel combined immunodeficiency with skeletal dysplasia

一种新型联合免疫缺陷伴骨骼发育不良的特征

基本信息

批准号：
8886617
负责人：
Luigi Daniele Notarangelo
金额：
$ 26.44万
依托单位：
BOSTON CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-01-15 至 2016-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8886617
关键词：
Affect Architecture Autoantigens Autologous Biological Branchial arch structure CD4 Positive T Lymphocytes CD8B1 gene Cartilage Cell surface Cells Clustered Regularly Interspaced Short Palindromic Repeats Data Defect Development Disease Disease model Dysplasia Elderly Eosinophilia Exfoliative Dermatitis Family Female Gene Mutation Generations Genes Hair Hematopoietic Stem Cell Transplantation Heparan Sulfate Biosynthesis Heparan Sulfate Proteoglycan Heparitin Sulfate Human IgE Immune Immune system Immunity Immunologic Deficiency Syndromes In Vitro Infant Infection Lead Limb Bud Link Lymphatic Diseases Lymphopenia Mesenchyme Missense Mutation Mitogens Molecular Mus Mutation Neural Crest Organogenesis Parents Patients Pectoral Peripheral Phenotype Play Proteoglycan Recurrence Regulatory T-Lymphocyte Reporting Role Serum Severe Combined Immunodeficiency Siblings Skeletal Development Syndrome System Systems Development T cell differentiation T-Cell Development T-Lymphocyte Technology Testing Therapeutic Thymic epithelial cell Thymus Gland Tissues Zebrafish base cell type congenital immunodeficiency disease phenotype exome sequencing gene correction glycosyltransferase induced pluripotent stem cell insight male member morphogens mouse model mutant novel polysulfated glycosaminoglycan public health relevance skeletal skeletal dysplasia thymocyte thymus transplantation transcription factor

项目摘要

DESCRIPTION (provided by applicant): Immuno-osseous dysplasias (IOD) are a group of disorders characterized by immune deficiency and skeletal dysplasia. Schimke's disease (SIOD) and cartilage hair hypoplasia (CHH) represent the prototypic forms of these disorders, but several other cases of IOD with unknown molecular basis have been described. The immunodeficiency seen in IOD is often severe, and affects predominantly T lymphocytes. Immune dysregulation typical of Omenn syndrome (OS) has been reported in some patients with CHH. We have identified and studied two siblings (a male and a female) with rapidly progressive and fatal IOD. Both infants manifested T cell lymphopenia with markedly reduced number of CD8+ T cells, lack of proliferation to mitogens, hypogammaglobulinemia, increased serum IgE and eosinophilia. The elder sibling had features of OS, with erythroderma and expansion of oligoclonal and activated CD4+ T cells. No mutations were identified in the SMARCAL1 and RMRP genes, responsible for SIOD and CHH, respectively. Whole exome sequencing (WES) revealed that both siblings were homozygous, and both parents heterozygous, for a novel and drastic missense mutation (R339W) affecting a highly conserved residue of Exostosin-like 3 (EXTL3), a member of the exostosin (EXT) family of glycosyltransferases involved in heparan sulfate (HS) biosynthesis. HS are sulfated glycosaminoglycans that decorate cell surface and matrix proteoglycans. HS proteoglycans modulate the activity of morphogens that play a key role in skeletal development and T cell differentiation. Our overall hypothesis is that EXTL3 is critical for thymic development and that EXTL3 mutations in humans cause a novel form of IOD. In support of our hypothesis, our preliminary data demonstrate that EXTL3 is expressed by human thymocytes, thymic epithelial cells (TECs), and peripheral T cells. Moreover, mutation of Extl3 in zebrafish causes defects of limb bud development, and impaired thymic T cell development. To test our hypothesis, and to investigate the cellular basis of the immunodeficiency associated with EXTL3 mutations, we will generate and characterize mouse models with tissue-specific disruption of the Extl3 gene in neural crest mesenchyme cells, TECs, or thymocytes. All of these cell types produce HS and are critically involved in thymus organogenesis and T cell development. In parallel, in order to demonstrate the disease-causing effect of the EXTL3 p.R339W mutation identified in the affected siblings, we will perform disease modeling using patient-derived induced pluripotent stem cells (iPSCs). We will use the CRISPR/Cas9 technology to correct the EXTL3 p.R339W mutation in patient-derived iPSCs. In order to define the cell autonomous effect of the EXTL3 mutation, we will differentiate both mutant and gene-corrected iPSCs to TECs and T cells, and we will study HS biosynthesis under the same experimental conditions. We anticipate that this study will provide novel important insights on the biological role of HSPGs in immune system development and function, and will help define the optimal therapeutic approach to correct the immunodeficiency of this condition.

描述（由申请人提供）：免疫性骨发育不良（IOD）是一组以免疫缺陷和骨骼发育不良（SIOD）和软骨毛发育不全（CHH）为特征的疾病，但还有其他几种疾病的典型形式。分子基础未知的 IOD 病例已有描述，IOD 中的免疫缺陷通常很严重，并且主要影响免疫细胞。据报道，一些 CHH 患者存在典型的 Omenn 综合征 (OS) 失调现象。我们已发现并研究了两个患有快速进展和致命 IOD 的兄弟姐妹，这两个婴儿都表现出 T 细胞淋巴细胞减少症，且 CD8+ 数量显着减少。 T 细胞、缺乏有丝分裂原增殖、低丙种球蛋白血症、血清 IgE 升高和嗜酸性粒细胞增多。哥哥姐姐具有 OS 特征，伴有红皮病和寡克隆和扩张。激活的 CD4+ T 细胞中，分别负责 SIOD 和 CHH 的 SMARCAL1 和 RMRP 基因中没有发现突变，全外显子组测序 (WES) 显示，兄弟姐妹都是纯合子，而父母都是杂合子，存在一种新的严重错义突变。 R339W) 影响外骨蛋白样 3 (EXTL3) 的高度保守残基，外骨蛋白样 3 (EXTL3) 是外骨蛋白 (EXT) 家族的成员参与硫酸乙酰肝素 (HS) 生物合成的糖基转移酶是装饰细胞表面的硫酸化糖胺聚糖，而基质蛋白聚糖可调节在骨骼发育和 T 细胞分化中发挥关键作用的形态发生素的活性。胸腺发育和人类 EXTL3 突变会导致一种新型 IOD。为了支持我们的假设，我们的初步数据表明 EXTL3 由人类胸腺细胞、胸腺上皮细胞 (TEC) 和外周 T 细胞表达。此外，斑马鱼中的 Extl3 突变会导致肢芽发育缺陷和胸腺 T 细胞发育受损。为了检验我们的假设，并研究与 EXTL3 突变相关的免疫缺陷的细胞基础，我们将生成并表征神经中 Extl3 基因的组织特异性破坏的小鼠模型。嵴间充质细胞、TEC 或胸腺细胞均产生 HS，并同时参与胸腺器官发生和 T 细胞发育，以证明 EXTL3 p.R339W 突变的致病作用。对于受影响的兄弟姐妹，我们将使用患者来源的诱导多能干细胞 (iPSC) 进行疾病建模，我们将使用 CRISPR/Cas9 技术来纠正 EXTL3。患者来源的 iPSC 中的 p.R339W 突变为了确定 EXTL3 突变的细胞自主效应，我们将突变型和基因校正的 iPSC 与 TEC 和 T 细胞区分开来，并且我们将在相同的实验条件下研究 HS 生物合成。我们预计这项研究将为 HSPG 在免疫系统发育和功能中的生物学作用提供新的重要见解，并将有助于确定纠正这种情况的免疫缺陷的最佳治疗方法。