Function of L-Type Ca2+ Channels in B-Lymphocytes

B 淋巴细胞中 L 型 Ca2 通道的功能

• 批准号: 7450983
• 负责人: ANNE-LAURE PERRAUD
• 金额: $ 23.4万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7450983
• 关键词: Affect; Antibody Formation; B-Cell Development; B-Lymphocytes; Binding; Biological Models; Biological Process; Biology; Calcium; Cardiac; Cell Line; Cell membrane; Cell physiology; Cells; Cellular Membrane; Class; Complement; Complement 3d Receptors; Complex; Condition; Diltiazem; Elevation; Ensure; Event; Family; Gene Expression; Generations; Genes; Genetic; Genomics; Hereditary Disease; Homeostasis; Hypertension; Immune; Immune Cell Activation; Immune response; Immune system; In Vitro; Individual; Ion Channel; Ions; Knockout Mice; Ligation; Location; Lymphocyte; Mediating; Membrane Proteins; Molecular; Mouse Strains; Mus; Mutation; Names; Neurons; Organism; Patients; Pattern; Permeability; Personal Satisfaction; Pharmaceutical Preparations; Phase; Play; Public Health; Receptors, Antigen, B-Cell; Regulation; Role; Role playing therapy; Signal Transduction; Surface; Symptoms; System; Timothy syndrome; Ursidae Family; Variant; Verapamil; cell type; design; drug development; extracellular; in vivo; in vivo Model; inhibitor/antagonist; member; mouse model; mutant; response; therapeutic target

DESCRIPTION (provided by applicant): Calcium (Ca2+) plays a central role in Biology as a universal messenger by allowing cells to efficiently respond to extracellular signals via modulation of its intracellular level. The permeability of cellular membranes for Ca2+ ions is therefore carefully regulated by membrane proteins called ion channels. The mounting of an efficient immune response also requires an extended period of intracellular Ca2+ elevation in immune cells such as lymphocytes. B-lymphocytes are the cells of the adaptive immune system that are responsible for the production of antibodies. The diversity of ion channels expressed in B lymphocytes is greater than originally anticipated, and includes molecules such as L-type CaV-channel variants that were originally assumed to be specific for so-called excitable cells, such as cardiac or neuronal cells. Although the presence of these L-type channels in B-cells is well established, their function remains to be elucidated. The aim of this proposal is to establish genetic model systems allowing us to investigate the role of individual members of the L-type channel family in the B-cell context. This includes the generation and functional characterization of B-cell lines lacking L-type channels that can subsequently be complemented with wildtype and mutant versions of the channels. We also plan to analyze the function of these molecules in vivo by studying the effect of B-cell restricted genomic deletion of L-type channels in an existing mouse model. Because the immune response is a very complex interplay of numerous cell types in multiple locations of the body, this in vivo model represents a complementary approach to the cell lines that will allow us to study the potential role of L-type channels in B-cell development and activation in the context of the complete organism. Public Health Relevance Statement: L-type Ca2+ channels are important therapeutic targets of a class of drugs that include verapamil and diltiazem, which are commonly used to treat conditions such as hypertension in patients. It has been shown in vitro that these drugs also inhibit the Ca2+-response of immune cells, although at higher concentrations than these applied therapeutically. This suggests that immune specific variants of these channels exist that are less sensitive towards these compounds. A promising avenue of immuno-modulatory drug development is therefore to design modified versions of these known channel inhibitors that would specifically bind and inhibit the immune system versions of L-type channels. To this aim, it is essential to identify the functional variants of these channels expressed in the immune context, and their precise role during immune response activation. Furthermore, these findings could also be beneficial to young patients suffering from rare complex genetic disorders affecting L-type channel function, and who are known to show symptoms consistent with immuno-deficiencies. This proposal will contribute to answering these important questions by investigating the role of these channels in B-lymphocytes.

描述（由申请人提供）：钙（Ca2+）作为通用信使在生物学中发挥着核心作用，它允许细胞通过调节其细胞内水平来有效地响应细胞外信号。因此，细胞膜对 Ca2+ 离子的渗透性受到称为离子通道的膜蛋白的仔细调节。有效免疫反应的建立还需要免疫细胞（例如淋巴细胞）中较长时间的细胞内 Ca2+ 升高。 B 淋巴细胞是适应性免疫系统的细胞，负责产生抗体。 B 淋巴细胞中表达的离子通道的多样性比最初预期的要多，其中包括 L 型 CaV 通道变体等分子，最初认为这些分子对所谓的可兴奋细胞（如心脏或神经元细胞）具有特异性。尽管 B 细胞中这些 L 型通道的存在已得到充分证实，但它们的功能仍有待阐明。该提案的目的是建立遗传模型系统，使我们能够研究 L 型通道家族个体成员在 B 细胞环境中的作用。这包括缺乏 L 型通道的 B 细胞系的生成和功能表征，随后可以用野生型和突变型通道进行补充。我们还计划通过研究现有小鼠模型中 L 型通道的 B 细胞限制性基因组删除的影响来分析这些分子的体内功能。由于免疫反应是身体多个部位的多种细胞类型非常复杂的相互作用，因此这种体内模型代表了细胞系的一种补充方法，使我们能够研究 L 型通道在整个生物体中 B 细胞发育和激活中的潜在作用。公共卫生相关性声明：L 型 Ca2+ 通道是维拉帕米和地尔硫卓等一类药物的重要治疗靶点，这些药物通常用于治疗患者的高血压等疾病。体外研究表明，这些药物也能抑制免疫细胞的 Ca2+ 反应，尽管浓度高于治疗时使用的浓度。这表明这些通道存在免疫特异性变体，对这些化合物不太敏感。因此，免疫调节药物开发的一个有前途的途径是设计这些已知通道抑制剂的修饰版本，其将特异性结合并抑制 L 型通道的免疫系统版本。为此，必须确定这些通道在免疫环境中表达的功能变异，以及它们在免疫反应激活过程中的精确作用。此外，这些发现也可能对患有影响 L 型通道功能的罕见复杂遗传性疾病的年轻患者有益，并且已知这些患者表现出与免疫缺陷一致的症状。该提案将通过研究这些通道在 B 淋巴细胞中的作用，有助于回答这些重要问题。