Regulation of B Lymphocyte Survival and Differentiation by HSH2

HSH2 对 B 淋巴细胞存活和分化的调节

• 批准号: 7612425
• 负责人: LOUIS B JUSTEMENT
• 金额: $ 6.71万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-23 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7612425
• 关键词: Adaptor Signaling Protein; Antigen Receptors; Apoptosis; Apoptotic; Attenuated; Autoimmunity; B-Cell Development; B-Lymphocytes; Binding; Biochemical; Bone Marrow; CD4 Positive T Lymphocytes; Cell Line; Cell Survival; Cell physiology; Cells; Cellular biology; Cessation of life; DNA; Development; Disease Progression; Doctor of Philosophy; Effector Cell; Equilibrium; Etiology; Event; Exhibits; Family; Flow Cytometry; Gene Targeting; Goals; Homeostasis; Hour; Immunofluorescence Immunologic; Interleukin-4; Ionomycin; Laboratories; Lead; Life; Ligation; Link; Localized; Lymphocyte; Lymphocyte Biology; Malignant Neoplasms; Mediating; Membrane; Mitochondria; Molecular; Monoclonal Antibody HuM291; Muromonab-CD3; Mus; Nature; Outer Mitochondrial Membrane; Pathway interactions; Peripheral; Peritoneum; Physiological; Play; Population; Proteins; Regulation; Regulatory Pathway; Research Personnel; Role; Signal Transduction; Spleen; Src homology 2 domain-containing, transforming protein 1; Staining method; Stains; Stimulus; Structure; T-Lymphocyte; TNFRSF5 gene; TNFSF5 gene; Thymus Gland; Tissue Stains; Transcriptional Activation; Transgenes; Up-Regulation; Western Blotting; anti-IgM; base; computerized data processing; immune function; insight; knock-down; loss of function; macrophage; novel; programs; receptor; research study; response; retroviral-mediated; small hairpin RNA; thymocyte

The goal of this proposal is to elucidate the physiological role of the novel adaptor protein HSH2 (JHematopoietic SH2 protein) in regulation of B lymphocyte biology. Studies conducted in our laboratory have demonstrated that HSH2 is expressed at low basal levels in splenic B cells and that its expression is induced in response to stimuli that bind to distinct families of receptors that promote survival and differentiation, including CD40L, IL-4, LPS, CpG DMA and BLyS (BAFF). Up-regulation of HSH2 expression was shown to be dependent on activation of NF-icB and correlates with initiation of a survival responsethat includes up-.regulation of Bcl-Xi.. Retroviral-mediated expression of HSH2 in the WEHI-231 B cell line, which undergoes apoptosis in response to BCR ligation, was observed to enhance survival and mitochondrial stability. Similarly, enhanced survival of WEHI-231 cells in response to CD40-mediated signaling directly correlated with up-regulation of HSH2 expression. Although HSH2 does not significantly alter BCR-proximal signal transduction, it was observed to maintain mitochondrial stability and this correlated with its ability to block up-regulation of Bim in response to BCR signaling. Moreover, HSH2 was found to interact with the anti-apoptotic protein HAX-1, which possessesa membrane-spanning region that targets it to the outer mitochondrial membrane. Preliminary studies have shown that the interaction between HSH2 and HAX-1 is important for the anti-apoptotic activity of HSH2. Therefore, HSH2 and HAX-1 may function together to regulate mitochondrial integrity and cell survival. To further elucidate the physiological role of HSH2 in regulation of B lymphocyte survival/differentiation, three specific aims have been proposed that will: 1) determine the physiological role of HSH2 in B lymphocyte development, homeostasis and immune function; 2) elucidate the role that HSH2 plays in regulating Bim expression in response to co-stimulation; and 3) determine the functional importance of the interaction between HSH2 and HAX-1 in regulating mitochondrial stability. Because HSH2 expression is induced in response to many of the key stimuli that are known to promote B cell survival and differentiation, this adaptor protein is likely to play an important role in regulating B cell homeostasis and immune function. Therefore, these studies will provide novel insight into the molecular mechanisms that maintain the balance between B lymphocyte survival and death leading to differentiation into humoral effector cells and will provide insight into the etiology and progression of diseases associated with aberrant B cell function, including cancer and autoimmunity.

该提案的目标是阐明新型接头蛋白 HSH2 的生理作用 （J造血 SH2 蛋白）在 B 淋巴细胞生物学调节中的作用。在我们的实验室进行的研究 已经证明HSH2在脾B细胞中以低基础水平表达，并且其表达是 响应于与不同受体家族结合的刺激而诱导，从而促进生存和 分化，包括 CD40L、IL-4、LPS、CpG DMA 和 BLyS (BAFF)。 HSH2表达上调 被证明依赖于 NF-icB 的激活，并与生存反应的启动相关 包括 Bcl-Xi 的上调。WEHI-231 B 细胞系中逆转录病毒介导的 HSH2 表达，其中 因 BCR 连接而发生细胞凋亡，观察到可增强存活率和线粒体 稳定。同样，直接响应 CD40 介导的信号传导可增强 WEHI-231 细胞的存活率 与 HSH2 表达上调相关。虽然 HSH2 不会显着改变 BCR 近端 信号转导，观察到维持线粒体稳定性，这与它的能力相关 阻断 Bim 响应 BCR 信号传导的上调。此外，HSH2被发现与 抗凋亡蛋白 HAX-1，其具有跨膜区域，可将其靶向外层 线粒体膜。初步研究表明HSH2与HAX-1之间的相互作用是 HSH2 的抗凋亡活性很重要。因此，HSH2 和 HAX-1 可能共同发挥作用 调节线粒体完整性和细胞存活。进一步阐明HSH2在 B 淋巴细胞存活/分化的调节，提出了三个具体目标：1) 确定HSH2在B淋巴细胞发育、稳态和免疫功能中的生理作用； 2) 阐明HSH2在响应共刺激下调节Bim表达中所起的作用；和 3) 确定 HSH2 和 HAX-1 之间相互作用在调节线粒体中的功能重要性 稳定。因为 HSH2 表达是响应许多已知的关键刺激而诱导的。 促进 B 细胞存活和分化，这种接头蛋白很可能在调节中发挥重要作用 B 细胞稳态和免疫功能。因此，这些研究将为我们提供新的见解 维持 B 淋巴细胞生存和死亡之间平衡的分子机制 分化为体液效应细胞，有助于深入了解疾病的病因和进展 与 B 细胞功能异常相关，包括癌症和自身免疫。