Calcium Signaling in Dendritic Cell Function

描述（由申请人提供）：树突状细胞（DC）是一种异质性的罕见白细胞，高度专门化，用于免疫监视，诱导和调节原发性免疫反应。这种独特的能力反映了它们连续取样微环境和摄取外来和自身抗原的能力。在遇到微生物、炎症分子或过敏原等形式的“危险”刺激后，DC转化为强效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细胞的激活。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。我们最近描述了两种新的钙信号通路。首先，我们确定了DC骨骼肌型ryanodine受体（RyR1）。RyR1是一个巨大的细胞内通道，可以放大细胞内小的钙瞬变，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，包括外泌体和无领导分泌蛋白。本提案的目标是确定DC中ryr -钙调控的途径。我们假设RyR1整合了多种细胞刺激，并介导驱动DC功能的钙通路。本文概述了一种跨学科的方法来研究这些钙信号机制的特性，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RyR1在DC开发和功能中的作用。目的2检测内源性和药理学激活剂RyR1对DC的影响。在Aim 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.