Ceramide membrane microdomains regulate cytokine secretion

神经酰胺膜微结构域调节细胞因子分泌

• 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
• 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; 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

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）：尽管肺泡上皮II型细胞（AECII）构成了肺泡空间的障碍，并产生表面活性剂以保持肺完整性，但肺中的独特AECII种群也可能在抗微生物免疫中发挥关键作用，通过分泌细胞因子（例如Monicocyte Chiontecytecytecytecte pa）对抗微生物免疫（MCPA）（McP.McP.-1）。但是，细胞因子分泌的机制在很大程度上尚不清楚。我们的长期目标是了解肺部防御的机制，从而确定治疗细菌感染的新策略。该应用的目的是表征 AECII的细胞因子分泌。我们假设AECII通过分泌细胞因子来发挥免疫作用，该因子通过膜微域重组的机制来调节。我们根据我们的最新研究和两条单独的证据来提出这一假设。首先，在高纯度细胞种群中，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，脂质筏（膜微区域）对先天免疫的重要性已经表明，特别是患有PA感染风险的CF患者通常可能由于神经酰胺缺乏症而造成异常的脂质筏功能。与此相一致，我们表明脂质筏可能参与了细胞因子MCP-1的分泌，该分泌位于富含神经酰胺的筏中。我们的理由是，阐明富含神经酰胺的微区域中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隔离，PA感染和先进的生化技术方面具有必要的专业知识。为了检验我们的假设，我们提出了以下两个特定目的：具体目的1：表征膜微区域的动态重组，在使用成像工具调节AECII和小鼠中的细胞因子分泌方面。我们的工作假设是，PA感染引发了影响细胞因子产生的膜微域的动态变化。特定目的2：定义膜微域调节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，并转移到专用域，在该结构域中启动了MCP-1的信号传导。由于细胞因子在各种生理和病理状况中的重要作用，这些新型机制将改善对其他类型细胞，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标。 公共卫生相关性：尽管肺泡上皮II型细胞（AECII）是肺中的结构和祖细胞，但它们也通过分泌细胞因子来提供免疫防御。这种独特的免疫力可能会严重增加对铜绿假单胞菌（PA）的宿主防御，这是一种细菌，可引起免疫缺陷个体的严重感染，例如艾滋病，结核病和囊性纤维化。我们假设AECII通过细胞膜微域的变化来分泌细胞因子，这是一种可能影响许多疾病过程的新机制。因此，我们的研究将为这种反复感染的新型治疗发展提供新的见解。