Activation of the NOD1 and NOD2 signaling pathways

NOD1 和 NOD2 信号通路的激活

基本信息

批准号：
10172844
负责人：
Arina Marijke Keestra-Gounder
金额：
$ 22.64万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-01 至 2022-11-30
项目状态：
已结题

项目摘要

PROJECT SUMMARY NOD1 and NOD2 are pattern recognition receptors that sense fragments of bacterial peptidoglycans, and are able to detect perturbations in cellular processes such as the modulation of the actin cytoskeleton and disturbance in endoplasmic reticulum (ER) homeostasis. Under different stressful conditions, such as bacterial and viral infections, protein misfolding and perturbations in calcium homeostasis, the ER is unable to maintain homeostasis and activates the unfolded protein response (UPR). Upon ER stress three transmembrane receptors, IRE1, PERK and ATF6 are activated and regulate biological processes such as inhibition of protein translation, autophagy, and inflammation to reestablish cellular homeostasis. NOD1 and NOD2 have been implicated in ER stress-induced inflammation, by acting downstream in the UPR to induce NF-B activation and IL-6 production. The exact mechanism how NOD1 and NOD2 can sense ER stress is currently unknown. NOD1 and NOD2 can also sense the activation of small Rho GTPases such as Rac1. Rac1 activation leads to membrane ruffling as well as activation of the transcription factor NF-B. We and others have shown that NOD1 and NOD2 interact with Rac1 at the cell membrane. The underlying mechanism of Rac1-mediated NOD1 and NOD2 activation is currently unknown. In the application we propose to study the mechanisms of peptidoglycan-independent activation of NOD1 and NOD2 by modulation of the actin cytoskeleton and thapsigargin-induced ER stress. Our central hypothesis is that NOD1 and NOD2 can detect cellular perturbations independent of peptidoglycan recognition. We will test key aspects of our hypothesis using the logical and innovative approach outlined in the following specific aims. Specific Aim 1. Determine the role of NOD1 and NOD2 in sensing ER stress. We will determine the contribution of calcium flux from the ER to the mitochondria in ER stress induced NOD1 and NOD2 activation. We will test our hypothesis that mitochondria damaged by ER stress release damage-associated molecular patterns (DAMPs) that activate NOD1 and NOD2. Specific Aim 2. Perturbations in cellular processes determines NOD1 and NOD2 localization. We will investigate the cellular localization of NOD1 and NOD2 in cells treated with thapsigargin to induce ER stress and in cells that express active Rac1 or Rac1 mutant forms that either induce cytoskeletal remodeling or NF-B activation. Characterizing and understanding the mechanisms of peptidoglycan-independent NOD1 and NOD2 activation provides a plausible explanation for the observation that viruses and parasites trigger NOD1 and NOD2 signaling. These findings are innovative new concepts and would markedly influence the current concepts of NOD1 and NOD2 biology.

项目摘要 NOD1和NOD2是模式识别受体，感知细菌的碎片，肽聚糖，并能够检测细胞过程中的扰动，例如肌动蛋白细胞骨架和内质网（ER）稳态的扰动。在不同的压力条件下，例如细菌以及病毒感染，蛋白质错误折叠和钙稳态的扰动，ER无法维持稳态并激活未折叠的蛋白质反应（UPR）。在ER应力下，三个跨膜受体，IRE1，PERK和ATF6被激活并调节生物学过程，例如抑制蛋白翻译，自噬和炎症，重新建立细胞稳态。 nod1和nod2已经通过在UPR中下游作用以诱导NF-B激活，在ER应力诱导的感染中实施和IL-6生产。 NOD1和NOD2如何感觉到ER应力的确切机制目前尚不清楚。 NOD1和NOD2还可以感觉到小rho GTPases（例如Rac1）的激活。 Rac1激活导致膜褶皱以及转录因子NF-B的激活。我们和其他人表明 NOD1和NOD2与细胞膜上的Rac1相互作用。 Rac1介导的基本机制 NOD1和NOD2激活目前尚不清楚。在应用中，我们建议研究通过调节肌动蛋白细胞骨架和NOD2的肽聚糖非依赖性激活 Thapigargin引起的ER应力。我们的中心假设是NOD1和NOD2可以检测到细胞扰动独立于PepperyDoglycan识别。我们将使用该假设的关键方面以下特定目的概述了逻辑和创新的方法。具体目标1。确定NOD1和NOD2在感应ER应力中的作用。我们将确定 ER应力诱导的NOD1和NOD2激活中钙通量从ER到线粒体的钙通量的贡献。我们将测试我们的假设，即通过ER应力释放损伤相关的分子损坏的线粒体激活NOD1和NOD2的模式（潮湿）。特定目标2。细胞过程中的扰动决定了NOD1和NOD2定位。我们将研究用Thepigargin处理的细胞中NOD1和NOD2的细胞定位以诱导ER 应力和表达活性Rac1或Rac1突变体形成的细胞，这些突变体形成诱导细胞骨架重塑或 NF-B激活。表征和理解辣糖独立的NOD1和 NOD2激活为病毒和寄生虫触发NOD1的观察结果提供了合理的解释和NOD2信号。这些发现是创新的新概念，将显着影响当前 NOD1和NOD2生物学的概念。