The mechanism of NK cell defects in human NEMO deficiency

人类NEMO缺陷导致NK细胞缺陷的机制

• 批准号: 7530223
• 负责人: Jordan Scott Orange
• 金额: $ 23.39万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7530223
• 关键词: Acute; Affect; Animal Model; Appendix; Area; Biochemical; Biological Assay; Cell model; Cell physiology; Cells; Confocal Microscopy; Cytomegalovirus; Cytoplasmic Granules; Data; Defect; Dependence; Development; Disease; Elements; Generations; Genes; Genetic Transcription; Genus Mycobacterium; Health; Human; Immune; Immune system; Immunity; Immunologic Deficiency Syndromes; Immunology; In Vitro; Infection; Interleukin-2; Interruption; Laboratories; Lead; Ligation; Lymphocyte; Lytic; Mediating; Mutation; NK Cell Activation; Natural Killer Cells; Numbers; Pathway interactions; Patients; Physiological Processes; Predisposition; Process; Protein Biosynthesis; Proteins; Public Health; Receptor Activation; Regulation; Role; Signal Transduction; Small Interfering RNA; Staging; Techniques; Testing; Therapeutic; Thinking; Virus; Work; cytotoxicity; immunological synapse; inhibitor/antagonist; insight; interest; killings; novel; pathogen; research study; transcription factor

DESCRIPTION (provided by applicant): Human primary immunodeficiency caused by hypomorphic mutation of the NF-?B essential modifier (NEMO) gene impairs several immunological functions and leads to grave infectious susceptibilities. The disease resulting from these mutations (NEMO-ID) arises from an inability of NEMO to effectively perform its typical function enabling activation of the NF-?B transcription factor after ligation of key immunoreceptors. Patients with NEMO-ID are vulnerable to infection with cytomegalovirus, which has led us to identify their having a defect of NK cell cytotoxicity. NK cells are lymphocytes of the innate immune system that are capable of killing through the process of directed secretion of lytic granules onto a target cell after forming an immunological synapse (IS). NK cells are especially useful in defense against cytomegalovirus and other viruses that employ strategies to evade adaptive immunity. This is underscored by several other primary immunodeficiencies affecting NK cells. Although a number of the immunological deficits in NEMO-ID are understood at a mechanistic level, that of NK cell cytotoxicity is not. Through the work proposed in this application we will determine the mechanism of the NK cell defect in NEMO-ID. This is relevant as NK cell deficiency adversely affects the health of patients with NEMO-ID and understanding its mechanism will likely suggest therapeutic strategies to specifically overcome it. Defining the mechanism of NK cell deficiency in NEMO-ID will also provide unexpected and novel insight into the function of cytolytic cells and the IS. In our studies of NK cells from NEMO-ID patients we have found that the defect is specific and can be circumvented after IL-2 stimulation. Thus it is unlikely that the NK cells are developmentally abnormal and a mechanism in which NEMO serves an acute role in NK cell cytotoxicity is likely. Through in vitro preliminary studies we have found that the NEMO-dependent NF-?B pathway is rapidly induced in NK cells after activation receptor ligation. This leads to rapid NF-?B-dependent gene transcription and synthesis of new proteins in a timeframe consistent with the cytolytic process. Using several approaches we have identified a limited number of NEMO- and NF-?B-dependent rapidly synthesized proteins in NK cells and are pursuing their role in enabling cytotoxicity and the lytic IS. Thus, our long term objective is to further establish this paradigm of NEMO function in NK cells and define a role for NEMO-dependent rapidly synthesized proteins in formation of the IS and cytotoxicity. Specifically we will: 1) define the stage of the NK cell IS that depends upon NEMO function and NF-?B activation; 2) determine the role of rapidly synthesized NEMO-dependent proteins in NK cell function; 3) determine if IL-2 can restore the expression of critical NEMO/NF-?B dependent proteins in NK cells with blocked NF-?B signaling. Cumulatively, these studies will determine the mechanism of NK cell deficiency in NEMO-ID, define a novel pathway of regulating cytolytic function and provide insight into potentially useful therapy for NEMO-ID patients. PUBLIC HEALTH RELEVANCE: Our proposal, "The Mechanism of NK Cell Defects in Human NEMO Deficiency", is aimed at understanding why patients with hypomorphic mutations in the NEMO gene have defective NK cell function. We believe the answer is that NEMO serves a surprising role in rapid transcription and protein synthesis to enable NK cell cytotoxicity. Our work will test this hypothesis and be of broad relevance in that it will define a novel mechanism by which immunological function can be regulated as well as more specific insight into NK cells in NEMO deficiency that may allow for rational therapies.

描述（申请人提供）：由 NF-κB 必需修饰因子（NEMO）基因亚等位性突变引起的人类原发性免疫缺陷会损害多种免疫功能并导致严重的感染易感性。这些突变 (NEMO-ID) 引起的疾病是由于 NEMO 无法有效执行其典型功能，即在关键免疫受体连接后激活 NF-κB 转录因子。 NEMO-ID 患者容易受到巨细胞病毒感染，这使我们发现他们存在 NK 细胞毒性缺陷。 NK 细胞是先天免疫系统的淋巴细胞，能够在形成免疫突触 (IS) 后通过将裂解颗粒定向分泌到靶细胞上来进行杀伤。 NK 细胞在防御巨细胞病毒和其他采用逃避适应性免疫策略的病毒方面特别有用。影响 NK 细胞的其他几种原发性免疫缺陷也强调了这一点。尽管 NEMO-ID 中的许多免疫缺陷在机制水平上已被了解，但 NK 细胞的细胞毒性却并非如此。通过本申请中提出的工作，我们将确定 NEMO-ID 中 NK 细胞缺陷的机制。这是相关的，因为 NK 细胞缺乏会对 NEMO-ID 患者的健康产生不利影响，了解其机制可能会提出专门克服它的治疗策略。定义 NEMO-ID 中 NK 细胞缺陷的机制也将为溶细胞细胞和 IS 的功能提供意想不到的新颖见解。在我们对 NEMO-ID 患者 NK 细胞的研究中，我们发现这种缺陷是特异性的，并且可以在 IL-2 刺激后被规避。因此，NK 细胞不太可能出现发育异常，并且 NEMO 在 NK 细胞的细胞毒性中发挥重要作用的机制可能是存在的。通过体外初步研究，我们发现在激活受体连接后，NEMO依赖性NF-κB通路在NK细胞中被迅速诱导。这导致 NF-κB 依赖性基因在与细胞溶解过程一致的时间范围内快速转录和合成新蛋白质。使用多种方法，我们已经鉴定了 NK 细胞中有限数量的 NEMO 和 NF-κB 依赖性快速合成蛋白，并正在研究它们在细胞毒性和裂解性 IS 中的作用。因此，我们的长期目标是进一步建立 NK 细胞中 NEMO 功能的范例，并定义 NEMO 依赖性快速合成蛋白在 IS 形成和细胞毒性中的作用。具体来说，我们将： 1) 定义 NK 细胞 IS 的阶段，该阶段取决于 NEMO 功能和 NF-κB 激活； 2）确定快速合成的NEMO依赖性蛋白在NK细胞功能中的作用； 3) 确定IL-2是否可以恢复NF-κB信号传导受阻的NK细胞中关键NEMO/NF-κB依赖性蛋白的表达。总之，这些研究将确定 NEMO-ID 中 NK 细胞缺陷的机制，定义调节细胞溶解功能的新途径，并为 NEMO-ID 患者提供潜在有用的治疗方法。公共健康相关性：我们的提案“人类 NEMO 缺陷中 NK 细胞缺陷的机制”旨在了解为什么 NEMO 基因存在低等态突变的患者 NK 细胞功能有缺陷。我们相信答案是 NEMO 在快速转录和蛋白质合成中发挥着令人惊讶的作用，从而实现 NK 细胞的细胞毒性。我们的工作将检验这一假设，并具有广泛的相关性，因为它将定义一种新的机制，通过该机制可以调节免疫功能，并对 NEMO 缺陷中的 NK 细胞有更具体的了解，从而可以进行合理的治疗。