Distinctive role of ORAI3 channels in the effector T cell response

ORAI3 通道在效应 T 细胞反应中的独特作用

• 批准号: 10054359
• 负责人: Yousang Gwack
• 金额: $ 19.5万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10054359
• 关键词: Autoantigens; Autoimmunity; Cell physiology; Cells; Comparative Study; Cysteine; Environment; Exhibits; Experimental Autoimmune Encephalomyelitis; Family; Family member; Future; Genetic; Goals; Graft Rejection; Knock-out; Knockout Mice; Knowledge; Laboratories; Mediating; Molecular; Outcome; Oxidative Stress; Oxides; Pathogenicity; Pattern; Phenotype; Physiological; Production; Proteins; Reactive Oxygen Species; Regulation; Residual state; Resistance; Role; Signal Transduction; Solid; Structure; Structure-Activity Relationship; T cell response; T cell therapy; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; T-Lymphocyte Subsets; Therapeutic; Tissues; Work; autoreactive T cell; base; biophysical properties; cell type; cytokine; druggable target; effector T cell; extracellular; in vivo; innovation; knockout animal; member; novel; response; small molecule; therapeutic target

PROJECT SUMMARY The goal of this proposal is to understand the discrete roles of the highly druggable targets, ORAI proteins in T cells for potential therapeutic exploitation. T cells require high and sustained levels of Ca2+ signaling for activation. Ca2+ signaling triggered by T cell receptor stimulation is primarily mediated by CRAC (Ca2+ release- activated Ca2+) channels that consist of the pore subunits, ORAI proteins. ORAI family members, ORAI1, ORAI2, and ORAI3, share a similar structure and can mediate CRAC currents but display distinct expression patterns and biophysical properties. Orai1 knockout (KO) effector T cells exhibit a reduction in Ca2+ entry, cytokine expression, and pathogenicity but also showed significant residual activity (20-40% of WT cells). These observations suggest that either ORAI2 or ORAI3 also contributes to Ca2+ entry in effector T cells. We find that, while deletion of Orai2 marginally influenced the function of effector T cells, Orai3 deletion substantially decreased Ca2+ entry and cytokine production. ORAI3 shares biophysical properties with ORAI1 but is unique in its resistance to inactivation by elevated intracellular Ca2+ levels and oxidative stress (e.g., reactive oxygen species, ROS) due to the absence of cysteine residues in its extracellular loop region. Based on these findings, the central hypothesis is that ORAI3 should be necessary for the in vivo effector T cell response in inflamed tissues. We propose to determine 1) the physiological outcomes of Orai3 deletion in effector T cells and 2) the distinctive role of ORAI3 homomultimeric channels in the effector T cell response. The proposed work is highly innovative because this study will determine the unknown role of ORAI3 in effector T cell responses. It will also define the distinct molecular identity of Ca2+ channels in T cell subsets. The idea to define the unique role of ORAI3 under oxidative stress at the inflamed tissue is conceptually innovative. This study to understand the physiological outcomes of blocking heteromeric or homomeric ORAI3 channels in the effector T cell response will have a significant positive impact on future therapeutic exploitation of the ORAI channels to treat autoimmunity or transplant rejection.

项目概要 该提案的目标是了解高药物靶标 ORAI 蛋白在 T 细胞中的离散作用。 细胞用于潜在的治疗开发。 T 细胞需要高且持续水平的 Ca2+ 信号传导 激活。 T 细胞受体刺激触发的 Ca2+ 信号传导主要由 CRAC（Ca2+ 释放- 激活的 Ca2+）通道，由孔亚基 ORAI 蛋白组成。 ORAI家族成员，ORAI1， ORAI2 和 ORAI3 具有相似的结构，可以介导 CRAC 电流，但表现出不同的表达 模式和生物物理特性。 Orai1 敲除 (KO) 效应 T 细胞表现出 Ca2+ 进入减少， 细胞因子表达和致病性，但也显示出显着的残留活性（WT 细胞的 20-40%）。 这些观察结果表明 ORAI2 或 ORAI3 也有助于 Ca2+ 进入效应 T 细胞。我们 发现，虽然 Orai2 的缺失对效应 T 细胞的功能影响微乎其微，但 Orai3 的缺失 显着减少 Ca2+ 进入和细胞因子产生。 ORAI3 与 ORAI1 具有相同的生物物理特性 但其独特之处在于其对细胞内 Ca2+ 水平升高和氧化应激（例如， 由于其细胞外环区域不存在半胱氨酸残基，因此产生活性氧（ROS）。基于 根据这些发现，中心假设是 ORAI3 对于体内效应 T 细胞来说是必需的 发炎组织的反应。我们建议确定 1) Orai3 缺失的生理结果 效应 T 细胞；2) ORAI3 同多聚体通道在效应 T 细胞反应中的独特作用。 拟议的工作具有高度创新性，因为这项研究将确定 ORAI3 在 效应T细胞反应。它还将定义 T 细胞亚群中 Ca2+ 通道的独特分子特性。 定义 ORAI3 在氧化应激下发炎组织的独特作用的想法在概念上是 创新的。本研究旨在了解阻断异聚或同聚 ORAI3 的生理结果 效应 T 细胞反应中的通道将对未来的治疗开发产生重大积极影响 ORAI 通道用于治疗自身免疫或移植排斥。