Calcium Signaling in Dendritic Cell Function

描述（由申请人提供）：树突状细胞（DC）是一种高度特异性的罕见白细胞异质群体，用于免疫监视以及诱导和调节原发性免疫应答。这种独特的能力反映了它们连续采样微环境并摄取外来和自身抗原的能力。在遇到微生物、炎症分子或过敏原形式的“危险”刺激后，DC转化为有效的刺激细胞并迁移到次级淋巴组织，在那里它们触发抗原特异性效应T细胞的活化。这些过程背后的信号通路无疑是复杂的，但细胞内钙似乎起着至关重要的作用。我们最近的特点是两个新的钙信号通路在DC。首先，我们已经确定了骨骼肌型兰尼碱受体（RyR 1）在DC。RyR 1是一个巨大的细胞内通道，可以放大细胞内的小钙瞬变，产生更大的，持续的钙升高。其次，我们已经证明，钙通量触发DC的快速分泌。这些通路使DC能够快速响应外部刺激，并释放自分泌和旁分泌信号因子，包括外泌体和无前导分泌蛋白。该提议的目标是确定DC中的RyRl-钙调节途径。我们假设RyR 1整合了多种细胞刺激，并介导了驱动DC功能的钙通道。概述了一种跨学科的方法来研究这些钙信号传导机制的特性，并了解它们如何参与DC生物学。我们将通过追求以下具体目标来实现本提案的目标：目标1旨在确定RyR 1在DC发育和功能中的作用。目的2测试RyR 1的内源性和药理学激活剂对DC的影响。在目标3中，我们将阐明钙触发分泌在DC中的作用。

DESCRIPTION (provided by applicant): Dendritic cells (DC) are a heterogeneous population of rare leukocytes highly specialized for immune-surveillance, and the induction and regulation of primary immune responses. This unique capacity reflects their ability to continuously sample the microenvironment and ingest foreign and self-antigens. After encountering a "danger" stimulus in the form of microbes, inflammatory molecules or allergens, DC transform into potent stimulatory cells and migrate to secondary lymphoid tissues, where they trigger the activation of antigen-specific effector T cells. The signaling pathways that underlie these processes are undoubtedly complex, but intracellular calcium appears to play a crucial role. We have recently characterized two novel calcium signaling pathways in DC. First, we have identified the skeletal muscle-type ryanodine receptor (RyR1) in DC. RyR1 is a massive intracellular channel that can amplify small calcium transients within a cell to produce much larger, sustained calcium rises. Second, we have demonstrated that calcium fluxes trigger rapid secretion by DC. Such pathways enable DC to respond rapidly to external stimuli, and release autocrine and paracrine signaling factors including exosomes and leaderless secretory proteins. The goal of this proposal is to determine the RyRl-calcium regulated pathways in DC. We hypothesize that RyR1 integrates diverse cellular stimuli, and mediates the calcium pathways that drive DC function. An inter-disciplinary approach is outlined to investigate the properties of these calcium signaling mechanisms and understand how they participate in DC biology. We will accomplish the objectives of this proposal by pursuing the following specific aims: Aim 1 is designed to determine the role of RyR1 during DC development and function. Aim 2 tests the impact of endogenous and pharmacologic activators of RyR1 on DC. In Aim 3, we will elucidate the role of calcium-triggered secretion in DC.