Elucidation of the mechanism of disease of VEXAS Syndrome

阐明VEXAS综合征的发病机制

• 批准号: 10752251
• 负责人: Samuel James Magaziner
• 金额: $ 5.27万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10752251
• 关键词: Ablation; Accounting; Address; Adrenal Cortex Hormones; Affect; Age; Automobile Driving; Biological; Biological Models; Bone Marrow; Bone Marrow Diseases; Cell Culture Techniques; Cell Death; Cell Line; Cell model; Cells; Charge; Chinese Hamster; Clonal Expansion; Clonal Hematopoietic Stem Cell; Complementary DNA; Cytoplasm; Data; Defect; Degradation Pathway; Disease; Disease Progression; Disparate; Dose; Dysmyelopoietic Syndromes; Elderly; Endoplasmic Reticulum; Enzymes; Future; Genes; Health; Hematological Disease; Hematology; Hematopoietic stem cells; Homeostasis; Human; Immune; Inflammation; Inflammatory; Investigation; Link; Lymphocyte; Malignant Neoplasms; Mediating; Methionine; Modeling; Molecular Target; Mutation; Myelogenous; Myeloid Cells; Neurodegenerative Disorders; Nuclear; Ovary; Pancytopenia; Pathogenesis; Pathway interactions; Patients; Phenotype; Process; Protein Isoforms; Proteins; Proteomics; Regulation; Relapsing polychondritis; Residual state; Role; Site; Syndrome; Temperature; Testing; Therapeutic; Therapeutic Intervention; Transgenic Organisms; Translating; Translations; U937 Cells; UBE2G2 gene; Ubiquitin-Activating Enzymes; Ubiquitin-Conjugating Enzymes; Vacuole; Validation; Variant; Vasculitis; X Chromosome; autoinflammatory; autoinflammatory diseases; cytokine; male; men; molecular targeted therapies; monocyte; mortality; mutant; novel; response; small hairpin RNA; small molecule; small molecule inhibitor; transcriptomics; ubiquitin ligase; ubiquitin-protein ligase

PROJECT SUMMARY Elucidation of a newly characterized clonal bone marrow and autoinflammatory disease, VEXAS Syndrome, prompts re-examination of the master regulator of ubiquitylation, UBA1. VEXAS stands for Vacuoles, E1, X- linked, Autoinflammatory, Somatic syndrome and presents with disparate inflammatory (e.g. relapsing polychondritis, vasculitides) and hematologic (e.g. pancytopenia, myelodysplastic syndrome) conditions. The disease is present in 1:4000 men over the age of 50 and has a 40% mortality rate. Current therapeutic treatment is limited to high dose corticosteroids. In affected patients, acquired or somatic variants in the UBA1 gene are present in hematopoietic stem cells (HPSCs) and become lineage restricted to myeloid cells. VEXAS presents primarily in elderly males as UBA1 is located on the X-chromosome. UBA1 encodes the primary ubiquitin (Ub) activating enzyme (E1), accounting for over 97% of all downstream ubiquitylation. Protein ubiquitylation occurs via a tightly regulated enzymatic cascade where sequential activation of E1 to Ub-conjugating enzyme (E2) to Ub-ligase (E3) enzymes ultimately leads to substrate ubiquitylation. Prior studies have predominantly focused on the role of E3 ligases in disease progression due to their protein-specific targeting in ubiquitylation. Far less is known regarding the role of UBA1 in disease pathogenesis. Notably, VEXAS highlights the importance of UBA1 in maintaining immune homeostasis and driving clonal blood disease. Through transcriptomic and cytokine profiling approaches, our group has identified mutant myeloid cells as the primary drivers of inflammation although the underlying mechanism remains unclear. Here I propose to determine the mechanism of VEXAS using unbiased approaches. Despite UBA1 mutation present in HSPCs, the mutation is lineage restricted to myeloid cells and absent in lymphocytes. Our preliminary results utilizing a temperature sensitive cell line (Chinese Hamster Ovary [CHO] line ts20) suggests VEXAS mutant UBA1 fails to charge the cognate E2s of the endoplasmic reticulum associated degradation pathway (ERAD), UBE2J1 and UBE2G2, potentially upregulating the unfolded protein response (UPR). These findings suggest that inappropriate UBA1 expression may both drive disease in VEXAS and allow selective clonal expansion of a pro-inflammatory myeloid lineage as potentiated by specific downstream effectors possibly linked to ERAD and UPR. In this study I propose to 1) perform an unbiased delineation of novel effectors driving UBA1-dependent inflammation pathways and 2) functionally validate effectors identified through model systems and unbiased approaches through a combination of small molecule, biologic, and transgenic approaches. My combined studies will not only be important for elucidating the mechanism of disease and treatment in VEXAS but may also apply to a wider understanding of key cellular ubiquitylation processes, autoinflammatory disease, and bone marrow-derived diseases.

项目概要 阐明一种新特征的克隆骨髓和自身炎症性疾病，VEXAS 综合征， 提示重新检查泛素化的主调节因子 UBA1。 VEXAS 代表液泡、E1、X- 相关的自身炎症、躯体综合征，并表现出不同的炎症（例如复发性炎症） 多软骨炎、血管炎）和血液系统（例如全血细胞减少症、骨髓增生异常综合征）病症。这 50 岁以上男性中有 1:4000 患有该病，死亡率为 40%。目前的治疗方法 仅限于高剂量皮质类固醇。在受影响的患者中，UBA1 基因的获得性变异或体细胞变异是 存在于造血干细胞 (HPSC) 中并成为仅限于骨髓细胞的谱系。 VEXAS 呈现 主要见于老年男性，因为 UBA1 位于 X 染色体上。 UBA1 编码初级泛素 (Ub) 激活酶（E1），占所有下游泛素化的 97% 以上。蛋白质泛素化发生 通过严格调节的酶级联，依次激活 E1 至 Ub 结合酶 (E2) Ub 连接酶 (E3) 最终导致底物泛素化。先前的研究主要集中于 E3 连接酶由于其泛素化中的蛋白质特异性靶向而在疾病进展中的作用。少得多 UBA1 在疾病发病机制中的作用是已知的。值得注意的是，VEXAS 强调了 UBA1 维持免疫稳态和驱动克隆性血液疾病。通过转录组和细胞因子 通过分析方法，我们的小组已确定突变的骨髓细胞是炎症的主要驱动因素 尽管根本机制仍不清楚。这里我建议确定VEXAS的机制 使用公正的方法。尽管 HSPC 中存在 UBA1 突变，但该突变的谱系仅限于 骨髓细胞，淋巴细胞中不存在。我们利用温度敏感细胞系的初步结果 （中国仓鼠卵巢 [CHO] 系 ts20）表明 VEXAS 突变体 UBA1 无法对同源 E2 进行充电 内质网相关降解途径 (ERAD)、UBE2J1 和 UBE2G2，可能上调 未折叠蛋白反应（UPR）。这些发现表明，不适当的 UBA1 表达可能会 驱动 VEXAS 疾病并允许促炎性骨髓谱系选择性克隆扩增 可能与 ERAD 和 UPR 有关的特定下游效应子增强。在这项研究中，我建议 1) 对驱动 UBA1 依赖性炎症途径的新型效应器进行公正的描述；2) 通过组合对模型系统和无偏见方法识别的效应器进行功能验证 小分子、生物和转基因方法。我的综合研究不仅对 阐明 VEXAS 的疾病机制和治疗，但也可能适用于更广泛的理解 关键细胞泛素化过程、自身炎症性疾病和骨髓源性疾病。