New Roles of Magnesium as a Regulatory Ion in Immune Responses and Cell Behavior

镁作为调节离子在免疫反应和细胞行为中的新作用

• 批准号: 10272202
• 负责人: michael j lenardo
• 金额: $ 64.36万
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10272202
• 关键词: Adenosine; Affect; Africa; Allergic; Antiviral Agents; Antiviral Response; Apoptosis; Area; Autoimmune Process; B-Lymphocytes; Blood specimen; Burkitt Lymphoma; CD8-Positive T-Lymphocytes; Cells; Characteristics; Child; Chronic; Clinical; Cohort Studies; Congenital disorders of glycosylation; Cyclosporine; Cytometry; Data; Defect; Diagnosis; Diagnostic; Diagnostic tests; Dietary Supplementation; Disease; Divalent Cations; Double-Blind Method; Drug Targeting; Epithelial; Epithelium; Epstein-Barr Virus Infections; Equilibrium; Eukaryotic Cell; Evaluation; Exhibits; Experimental Animal Model; Flow Cytometry; Foundations; Genes; Genetic; Glycoproteins; Graft Rejection; Hodgkin Disease; Human; Human Herpesvirus 4; Immune; Immune response; Immunity; Immunologic Deficiency Syndromes; Immunologic Markers; Immunophenotyping; Immunosuppressive Agents; In Vitro; Incidence; Incubated; Individual; Inositol; International; Ions; Lead; Link; Lymphocyte; Lymphocyte Activation; Lymphoid; Lymphoma; Magnesium; Magnesium Deficiency; Malignant Neoplasms; Mammalian Cell; Mediator of activation protein; Messenger RNA; Methods; Mg supplementation; Modeling; Molecular; Mus; National Cancer Institute; Neoplasms; Nucleic Acids; Nutraceutical; Oral; Organism; PLC gamma1; Pathogenicity; Pathway interactions; Patients; Pharmacologic Substance; Phospholipids; Population; Predisposition; Primary Prevention; Production; Proteins; Regulation; Research Personnel; Risk; Role; Second Messenger Systems; Secondary Prevention; Serum; Site; Stimulus; Stomach; Surface; T-Cell Receptor; T-Lymphocyte; T-Lymphocyte and Natural Killer Cell; Testing; Transfection; autoimmune lymphoproliferative syndrome; body system; case control; cell behavior; cell growth regulation; clinical diagnostics; cohort; congenital immunodeficiency; effective intervention; experience; glycoproteomics; glycosylation; improved; in vivo; insight; interest; novel therapeutics; oral supplementation; placebo controlled trial; prevent; receptor; response; time use; tool; tripolyphosphate

The MAGT1 transporter is critically involved in the selective regulation of intracellular free Mg2+ levels in mammalian cells. The molecular functions of free Mg2+ in eukaryotic cells have not been fully established. We found that patients with genetic deficiencies in MAGT1 have high levels of Epstein-Barr virus (EBV) and a predisposition to lymphoma. In studying lymphocytes from these patients, we found that a deficiency of MAGT1 caused decreased basal intracellular free Mg2+ leading to defective expression of the natural killer activating receptor NKG2D in NK and CD8+ T cells. Without NKG2D, cytolytic responses against EBV are diminished, thereby revealing the first specific molecular function of intracellular basal free Mg2+ in eukaryotic cells. Intracellular free Mg2+, NKG2D expression and function can be rescued in vitro by incubating patient cells and elevated levels of Mg2+. Moreover, NKG2D expression and cytolytic function can be improved and EBV-infected cells reduced in vivo, in MAGT1-deficient patients by magnesium administration. Thus, our data indicate an important molecular function for free basal Mg2+ in immunity and demonstrate a requirement for NKG2D cytolytic function in an essential EBV antiviral response in humans. We are especially interested in pursuing additional questions related to the role of Mg2+ in the control of EBV. Despite being linked to both epithelial (nasopharyngeal and gastric) and lymphoid (Burkitt and Hodgkin lymphoma) malignancies, there are currently no known methods for primary or secondary prevention of chronic EBV infection or the associated malignancies. Our discovery that a genetic deficiency of a Mg2+ ion transporter caused a selective immunodeficiency that led to uncontrolled EBV infection and an extremely high rate of EBV+ lymphoma in affected children and that dietary supplementation with Mg2+ (a widely available and inexpensive nutraceutical) could correct the immune defect by increasing a specific antiviral receptor called NKG2D which markedly decreased or eliminated EBV offered a new hypothesis about chronic EBV in Africa. We are collaborating with Sam Mbulaiteye, a National Cancer Institute investigator, who studies EBV/lymphoma risk in Africa. We have carried out a preliminary study of previously collected case-control blood samples from Africa and showed that there was a statistically significant deficiency of serum Mg2+ in Burkitt lymphoma (BL) patients with high EBV. This preliminary study could not answer whether intracellular Mg2+ and NKG2D expression were deficient in these patients which requires flow cytometric analysis on site in Africa or whether these could be restored by adding more Mg2+ to the cells. However, these results held promise that endemic EBV and the consequent lymphomas could be prevented by simple dietary supplementation with Mg2+. While we initially found abnormalities of intracellular levels and transport of Mg2+ in patients with XMEN, our expanded patient cohort showed both total and ionized serum magnesium concentrations were normal and therefore not diagnostic of XMEN. Intracellular Mg2+ determination or T cell receptor-induced Mg2+ fluxes have been extensively tested and not proven useful for clinical diagnostic tests due to unreliability. Therefore, we still recommend our previously described NKG2D surface expression evaluation by flow cytometry as an excellent diagnostic tool, and this can now be augmented with the standard clinical diagnostic test. Like XMEN patients, Autoimmune Lymphoproliferative Syndrome (ALPS) patients also often present with elevated double negative naive T cells, defects in apoptosis, and secondary lymphoid expansion. Including ALPS patients in our study cohort allowed us to conduct deep immunophenotyping of 32 immune markers using time-of-flight mass cytometry and compare those to XMEN patients to seek distinguishable characteristics between the two diseases. Our analysis revealed that the abundance of two populations of naive B cells could differentially classify XMEN, ALPS, and healthy individuals. We also performed glycoproteomics analysis on T lymphocytes and showed that XMEN disease is a congenital disorder of glycosylation that affects a restricted subset of glycoproteins. Transfection of MAGT1 mRNA enabled us to rescue proteins with defective glycosylation. Together, these data provide new clinical and pathophysiological foundations with important ramifications for the diagnosis and treatment of XMEN disease.

MAGT1转运蛋白与哺乳动物细胞中细胞内游离MG2+水平的选择性调节有关。真核细胞中游离MG2+的分子功能尚未完全确定。我们发现，MAGT1中遗传缺陷的患者具有高水平的爱泼斯坦 - 巴尔病毒（EBV）和淋巴瘤易感性。在研究这些患者的淋巴细胞时，我们发现MAGT1的缺乏导致基础内游离MG2+降低，导致NK和CD8+ T细胞中天然杀伤受体NKG2D的表达有缺陷。没有NKG2D，针对EBV的细胞溶解反应会减少，从而揭示了真核细胞中细胞内基基基基Mg2+的第一个特异性分子功能。细胞内游离MG2+，NKG2D表达和功能可以通过孵育患者细胞和Mg2+水平升高来挽救。此外，可以通过镁给药，可以改善NKG2D表达和细胞溶解功能，并通过镁给予EBV感染的细胞在体内减少体内。因此，我们的数据表明免疫中游离基础MG2+的重要分子功能，并证明了人类必需的EBV抗病毒反应中NKG2D细胞溶解功能的要求。 我们特别有兴趣提出与MG2+在控制EBV中的作用有关的其他问题。尽管与上皮（鼻咽和胃）以及淋巴样（伯基特和霍奇金淋巴瘤）恶性肿瘤有联系，但目前尚无针对初级或二级预防慢性EBV感染或相关恶性肿瘤的预防方法的已知方法。 Our discovery that a genetic deficiency of a Mg2+ ion transporter caused a selective immunodeficiency that led to uncontrolled EBV infection and an extremely high rate of EBV+ lymphoma in affected children and that dietary supplementation with Mg2+ (a widely available and inexpensive nutraceutical) could correct the immune defect by increasing a specific antiviral receptor called NKG2D which markedly decreased or eliminated EBV提出了关于非洲慢性EBV的新假设。我们正在与国家癌症研究所研究员Sam Mbulaiteye合作，该研究人员研究非洲的EBV/淋巴瘤风险。我们已经对非洲的病例对照血液样本进行了初步研究，并表明Burkitt淋巴瘤（BL）EBV患者的血清MG2+具有统计学意义。这项初步研究无法回答细胞内MG2+和NKG2D表达是否缺乏这些患者，需要对非洲现场进行流式细胞术分析，或者是否可以通过向细胞添加更多的MG2+来恢复这些表达。但是，这些结果认为，通过简单的饮食补充MG2+可以预防流行EBV和随之而来的淋巴瘤。 虽然我们最初发现XMEN患者的细胞内水平和MG2+的运输异常，但我们扩大的患者队列显示总和离子化的血清镁浓度正常，因此未诊断为XMEN。细胞内MG2+测定或T细胞受体诱导的MG2+通量已经进行了广泛的测试，并且由于不可靠性而对临床诊断测试没有证实。因此，我们仍然建议我们先前描述的NKG2D表面表达评估通过流式细胞仪作为出色的诊断工具，现在可以通过标准的临床诊断测试来增强这种诊断。 像XMEN患者一样，自身免疫性淋巴增生综合征（ALP）患者也经常出现升高的双阴性幼稚T细胞，细胞凋亡缺陷和继发性淋巴样膨胀。在我们的研究队列中，包括阿尔卑斯山患者在内，使我们能够使用飞行时间质量细胞术对32个免疫标记进行深层免疫表型，并将这些标记与XMEN患者进行比较，以寻求两种疾病之间的可区分特征。我们的分析表明，两个天真的B细胞种群的丰度可以差异地对XMEN，ALPS和健康个体进行分类。我们还对T淋巴细胞进行了糖蛋白质组学分析，并表明XMEN疾病是一种糖基化的先天性疾病，影响糖蛋白的受限子集。 MAGT1 mRNA的转染使我们能够营救有缺陷的糖基化蛋白质。这些数据共同提供了新的临床和病理生理基础，并为XMen病的诊断和治疗带来了重要的影响。