Novel Calcium Release Mechanism Regulates Dendritic Cell Function

新型钙释放机制调节树突状细胞功能

• 批准号: 8495236
• 负责人: Santiago Partida-Sanchez
• 金额: $ 34.03万
• 依托单位: RESEARCH INST NATIONWIDE CHILDREN'S HOSP
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8495236
• 关键词: Adenosine Diphosphate Ribose; Affect; Antigen Presentation; Antigen-Presenting Cells; Binding Proteins; Biological; Calcium; Calcium/calmodulin-dependent protein kinase; Calpain; Cell Maturation; Cell membrane; Cell physiology; Cells; Cellular biology; Chemotaxis; Chronic; Clinical; Communicable Diseases; Crohn' s disease; Data; Dendritic Cells; Development; Disease; Endoplasmic Reticulum; Escherichia coli; Exhibits; Goals; Grant; Homeostasis; Immune; Immune response; Immune system; Immunity; Immunization; Infection; Infiltration; Inflammation; Inflammatory; Knowledge; Life; Lymphocyte; Lysosomes; Mediating; Mitogen-Activated Protein Kinase Kinases; Molecular; Mucous Membrane; Mus; Pathway interactions; Phagocytes; Phagocytosis; Phagosomes; Play; Process; Production; Protein Tyrosine Kinase; Psoriasis; Regulation; Relative (related person); Research; Rest; Role; Shapes; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Skin; Testing; Urinary tract; Urinary tract infection; Vesicle; Work; adaptive immunity; antigen processing; base; cell motility; cell type; chemokine; chemokine receptor; cytokine; design; extracellular; in vivo; insight; macrophage; migration; mouse model; neutrophil; new therapeutic target; novel; novel therapeutics; receptor; research study; response; sulfated glycoprotein 2; trafficking

DESCRIPTION (provided by applicant): Dendritic cells (DCs) are multi-potent regulators of the immune system. Many critical DC functions involve calcium (Ca2+) signaling. Ca2+ is the most versatile eukaryotic intracellular messenger that mediates regulation of many processes important to cell life. Ca2+ levels in DCs and many other immune cell types are tightly regulated through multiple mechanisms during the resting state as well as during activation. Chemokine receptor stimulation increases intracellular Ca2+ concentration ([Ca2+]i) and chemotaxis in DCs. Despite important advances in our understanding of Ca2+ signaling in lymphocytes, the molecular players involved in shaping intracellular Ca2+ in DCs remain to be characterized. The current paradigm states that increases in DC cytosolic Ca2+ levels are caused by release from endoplasmic reticulum (ER) Ca2+ stores and/or via influx of extracellular Ca2+ by opening of store-operated Ca2+ channels at the plasma membrane. We propose a novel Ca2+ release mechanism in DCs, which operates via a Ca2+ channel expressed on lysosomal compartments and, we postulate this pathway is essential for Ca2+-dependent DC functions. Preliminary data that support our proposal show: i) Exclusive localization of functional Ca2+-permeant melastatin-related transient receptor potential channel (TRPM2) in endolysosomal compartments of DCs. ii) Both adenosine diphosphoribose (ADPR) and chemokines induce TRPM2 mediated Ca2+ signals in DCs, iii) TRPM2 channel acts as a Ca2+ release channel in DCs. iv) TRPM2-deficient DCs exhibit impaired chemotactic responses to chemokines. v) TRPM2-deficient mice elicit reduced inflammatory recruitment upon infection. Based upon these data, we hypothesize that: TRPM2 functions as an intracellular lysosome- associated calcium release channel that regulates Ca2+-dependent processes in DCs. To critically test our hypothesis, we propose the following specific aims: Aim 1. Identify mechanisms of activation of Ca2+ release via TRPM2 channel, and elucidate how this pathway impacts on DC Ca2+-dependent functions. Aim 2. Define the specific roles for TRPM2-mediated Ca2+ signaling in DCs during inflammation, immunization and cellular inflammatory infiltration to the mucosa using a mouse model of urinary tract infection. The findings from this proposal will provide insights into how the intracellular function of TRPM2 channel affects Ca2+-mediated signal transduction pathways that play a central regulatory role during DC responses. The completion of these studies will unveil the utility of new pharmacological targets (ADPR and/or TRPM2) for manipulation of DCs' Ca2+responses and functions, and will further facilitate the design of new therapeutic strategies for chronic inflammatory or infectious diseases, where DCs may play important pathogenic roles.

描述（由申请人提供）：树突状细胞（DC）是免疫系统的多功能调节剂。许多关键的直流功能涉及钙（CA2+）信号传导。 Ca2+是最通用的真核细胞内信使，它介导了许多对细胞寿命重要的过程的调节。 DC中的Ca2+水平和许多其他免疫细胞类型在静止状态和激活过程中通过多种机制严格调节。趋化因子受体刺激增加了细胞内Ca2+浓度（[Ca2+] I）和DC中的趋化性。尽管我们了解淋巴细胞中Ca2+信号传导的重要进展，但与DC中塑造细胞内Ca2+的分子参与者尚待表征。当前的范式指出，直流胞质Ca2+水平的增加是由内质网（ER）Ca2+存储释放和/或通过在Plasmambrane上打开商店操作的Ca2+通道而引起的。我们在DC中提出了一种新型的Ca2+释放机制，该机制通过在溶酶体室上表达的Ca2+通道运行，我们假设该途径对于Ca2+依赖性DC功能至关重要。支持我们的提案的初步数据显示：i）DCS内溶液室中功能性CA2+ - 佩尔曼特菜单相关受体电位通道（TRPM2）的独家定位。 ii）腺苷二磷核酸酶（ADPR）和趋化因子均诱导DCS中的TRPM2介导的Ca2+信号，iii）TRPM2通道在DCS中充当Ca2+释放通道。 iv）缺陷DCS的TRPM2对趋化因子的趋化反应受损。 v）缺乏TRPM2的小鼠在感染后会减少炎症募集。基于这些数据，我们假设：TRPM2充当细胞内溶酶体相关的钙释放通道，可调节DC中的Ca2+依赖性过程。为了批判性检验我们的假设，我们提出了以下特定目的：目标1。通过TRPM2通道确定Ca2+释放激活的机制，并阐明该途径如何影响DC Ca2+依赖性函数。 AIM 2。使用尿路感染的小鼠模型，定义了炎症，免疫和细胞炎症性浸润对粘膜的DC中TRPM2介导的Ca2+信号传导的特定作用。该提案的发现将提供有关TRPM2通道的细胞内功能如何影响Ca2+介导的信号转导途径，这些途径在DC响应中起着中心调节作用。这些研究的完成将揭示新的药理学靶标（ADPR和/或TRPM2）的实用性，以操纵DCS的CA2+反应和功能，并将进一步促进针对慢性炎症或感染性疾病的新治疗策略的设计，DC可以在其中发挥重要的病原性疾病。