Ceramide membrane microdomains regulate cytokine secretion

神经酰胺膜微结构域调节细胞因子分泌

基本信息

批准号：
8374310
负责人：
Brij B Singh
金额：
$ 6.9万
依托单位：
UNIVERSITY OF NORTH DAKOTA
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-05-15 至 2014-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8374310
关键词：
Accounting Acquired Immunodeficiency Syndrome Affect Alveolar Antibiotic Resistance Antibiotics Asthma Bacteria Bacterial Infections Biochemical Biological Assay Bronchitis CCL2 gene Cell Death Cell membrane Cells Ceramides Chronic Obstructive Airway Disease Chronic Sinusitis Conditioned Culture Media Cystic Fibrosis Cytokine Signaling Data Development Disease Disease Progression Epithelial Epithelium Fatty Acids Goals Gram-Negative Bacterial Infections Health Homeostasis Hospital Charges Host Defense Host Defense Mechanism Hydrolysis Hypersensitivity Imaging Device Imaging Techniques Immune Immunity Individual Infection Infection Control Inflammation Inflammatory Investigation Knockout Mice Laboratories Link Lower respiratory tract structure Lung Maintenance Membrane Microdomains Microbe Monocyte Chemoattractant Proteins Mus Natural Immunity North Dakota Onset of illness Organ Physiological Play Population Prevention strategy Process Production Progressive Disease Proteins Pseudomonas aeruginosa Recurrence Regulation Research Resistance Risk Role Signal Transduction Staging Stem cells Techniques Testing Tuberculosis Type II Epithelial Receptor Cell Universities Work aged antimicrobial base cell growth cell type combat cystic fibrosis patients cytokine effective therapy imaging modality immune function improved insight interest new therapeutic target novel novel therapeutics pathogen respiratory spatiotemporal surfactant treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Although alveolar epithelial type II cells (AECII) form the barrier of alveolar spaces and produce surfactants to maintain lung integrity, the unique AECII population in the lung may also play a critical role in anti-microbial immunity by secreting cytokines, such as monocyte chemoattractant protein (MCP-1) against P. aeruginosa (PA) infection. However, the mechanism of cytokine secretion is largely unknown. Our long-term goal is to understand mechanisms of lung host defense, thereby identifying new strategies for treating bacterial infection. Our objective of this application is to characterize the mechanism of cytokine secretion by AECII. We hypothesize that AECII play immune roles by secreting cytokines, which is regulated through a mechanism of membrane microdomain reorganization. We have formulated this hypothesis based on our recent studies and two separate lines of evidence. First, in a high purity cell population, we found that a conditioned medium from PA-infected primary AECII enhanced AM immunity. On the other hand, the importance of lipid rafts (membrane microdomains) for innate immunity has been indicated by the fact that CF patients, who are particularly at risk for PA infection, may often suffer from abnormal lipid raft function due to ceramide deficiency and fatty-acid imbalance. Consistent with this, we showed that lipid rafts may be involved in the secretion of the cytokine MCP-1, which is localized in ceramide-rich rafts. Our rationale is that elucidating the relevant mechanism in ceramide-rich microdomains will define a general mechanism for cytokine secretion. Our laboratory is ideally suited for this research since we have the requisite expertise in AECII isolation, PA infection, and advanced biochemical techniques. To test our hypothesis, we propose the following two specific aims: Specific Aim 1: To characterize dynamic reorganization of membrane microdomains in regulating cytokine secretion in AECII and in mice using imaging tools. Our working hypothesis is that PA infection initiates dynamic changes in membrane microdomains that impact cytokine production. Specific Aim 2: To define the mechanism by which membrane microdomains regulate key cytokines required for PA defense. Our hypothesis is that ceramide is generated by hydrolysis and translocated to specialized domains, where it initiates signaling for production of MCP-1. Due to the important role of cytokines in various physiological and pathological conditions, these novel mechanisms will improve understanding of cytokine secretion for other types of cells, pathogens, and inflammatory situations, and thereby identifying new therapeutic targets. PUBLIC HEALTH RELEVANCE: Although alveolar epithelial type II cells (AECII) are structural and progenitor cells in the lung, they also provide immune defense by secreting cytokines. This unique immunity may critically increase host defense against P. aeruginosa (PA), a bacterium that causes severe infections in immunodeficient individuals, such as AIDS, tuberculosis and cystic fibrosis. We hypothesize that AECII secrete cytokines through changes in cell membrane microdomains, a novel mechanism that may impact many disease processes. Thus, our research will provide new insights into the development of novel treatment for this recurrent infection.

描述（由申请人提供）：虽然肺泡上皮 II 型细胞（AECII）形成肺泡腔屏障并产生表面活性剂以维持肺完整性，但肺中独特的 AECII 群体也可能通过分泌在抗微生物免疫中发挥关键作用。细胞因子，例如针对铜绿假单胞菌 (PA) 感染的单核细胞趋化蛋白 (MCP-1)。然而，细胞因子分泌的机制很大程度上未知。我们的长期目标是了解肺部宿主防御机制，从而确定治疗细菌感染的新策略。我们此应用的目的是表征该机制的特征 AECII 分泌细胞因子。我们假设 AECII 通过分泌细胞因子发挥免疫作用，细胞因子通过膜微域重组机制进行调节。我们根据最近的研究和两条单独的证据制定了这一假设。首先，在高纯度细胞群中，我们发现来自 PA 感染的原代 AECII 的条件培养基增强了 AM 免疫力。另一方面，脂筏（膜微结构域）对于先天免疫的重要性已被以下事实表明：CF 患者特别容易受到 PA 感染，由于神经酰胺缺乏和脂肪过多，经常会出现脂筏功能异常。 -酸不平衡。与此一致的是，我们发现脂筏可能参与细胞因子 MCP-1 的分泌，该细胞因子位于富含神经酰胺的脂筏中。我们的理由是，阐明富含神经酰胺的微域的相关机制将定义细胞因子分泌的一般机制。我们的实验室非常适合这项研究，因为我们在 AECII 分离、PA 感染和先进的生化技术方面拥有必要的专业知识。为了检验我们的假设，我们提出以下两个具体目标：具体目标 1：使用成像工具表征 AECII 和小鼠中膜微结构域在调节细胞因子分泌中的动态重组。我们的工作假设是 PA 感染引发膜微区的动态变化，从而影响细胞因子的产生。具体目标 2：确定膜微结构域调节 PA 防御所需的关键细胞因子的机制。我们的假设是，神经酰胺是通过水解产生的，并转移到专门的区域，在那里它启动产生 MCP-1 的信号传导。由于细胞因子在各种生理和病理条件下的重要作用，这些新机制将增进对其他类型细胞、病原体和炎症情况的细胞因子分泌的理解，从而确定新的治疗靶点。公共卫生相关性：尽管 II 型肺泡上皮细胞 (AECII) 是肺部的结构细胞和祖细胞，但它们也通过分泌细胞因子提供免疫防御。这种独特的免疫力可能会极大地增强宿主对铜绿假单胞菌（PA）的防御能力，铜绿假单胞菌是一种导致免疫缺陷个体严重感染的细菌，例如艾滋病、结核病和囊性纤维化。我们假设 AECII 通过细胞膜微区的变化分泌细胞因子，这是一种可能影响许多疾病过程的新机制。因此，我们的研究将为开发这种复发性感染的新疗法提供新的见解。