TARGETING THE TRANSIENT RECEPTOR POTENTIAL CHANNELS TO IMPROVE BOWEL DYSFUNCTION

针对瞬时受体的潜在通道来改善肠功能障碍

• 批准号: 8962583
• 负责人: Hongzhen Hu
• 金额: $ 35.45万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8962583
• 关键词: Ablation; Adverse effects; Anti-Inflammatory Agents; Anti-inflammatory; Biology; Bone Marrow; Bone Marrow Transplantation; Cells; Chemosensitization; Clinical; Clinical Research; Data; Development; Dinoprostone; Endotoxins; Enterochromaffin Cells; Figs - dietary; Functional disorder; Future; Gastrointestinal Motility; Gastrointestinal Surgical Procedures; Gastrointestinal Transit; Gastrointestinal tract structure; Genetic; Health; Healthcare Systems; Homeostasis; Hospitalization; Human; ITGAM gene; Ileus; Image; Immune; Immune system; In Vitro; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory disease of the intestine; Intestinal Motility; Intestines; Ion Channel; Lipopolysaccharides; Mediating; Modeling; Molecular; Morbidity - disease rate; Mus; Nitric Oxide; Operative Surgical Procedures; Patients; Pharmaceutical Preparations; Pilot Projects; Population Dynamics; Population Heterogeneity; Postoperative Period; Regulation; Role; Serotonin; Signal Pathway; Smooth Muscle Myocytes; Source; Swelling; Testing; Therapeutic; Tissues; Transgenic Mice; Trauma; United States; Vanilloid; Work; base; cell motility; diphtheria toxin receptor; gastrointestinal; genetic manipulation; immune function; improved; in vivo; insight; lipid mediator; macrophage; mast cell; motility disorder; mouse model; new therapeutic target; novel; novel therapeutic intervention; patch clamp; promoter; public health relevance; receptor; response; selective expression; sensor; toll-like receptor 4; warm temperature

 DESCRIPTION (provided by applicant): Postoperative ileus (POI) following gastrointestinal (GI) surgery leads to significant patient morbidity and prolonged hospitalizations. POI is a major health problem and a significant burden on the health care system, which is estimated at $750 million to $1 billion per year in the United States. Currently, no treatments have been completely successful in reducing POI's significant impacts on patients and health care system. Recent studies have demonstrated that intestinal manipulation and surgical trauma activate inflammatory macrophages (MΦ) and release inflammatory mediators such as nitric oxide (NO) to inhibit intestinal smooth muscle cells in POI. Therefore, suppression of the immune function has been considered as a promising means to treat POI. However, inhibition of the intestinal immune system could elicit severe side effects because intestinal immune system hosts near 70% of the entire immune system and is critical to immune homeostasis. Intestinal MΦ are a highly heterogeneous and dynamic population in the innate immune system. Preliminary studies show that transient receptor potential vanilloid 4 (TRPV4) channel, a molecular sensor of tissue damage and inflammation, is exclusively expressed by the F4/80+/CD206+ intestinal anti-inflammatory M2 MΦ. Activation of TRPV4 produces an intestinal contractile response and improves GI transit in a mouse model of POI. The current proposal aims to elucidate the cellular and molecular mechanisms underlying the activation of TRPV4 in the intestinal M2 MΦ. Ca2+ imaging and patch-clamp studies will be used to study the function of TRPV4 in intestinal MΦ. The requirement of bone marrow (BM)-derived MΦ in TRPV4-mediated contractile response will be determined by constructing chimeric mice by reciprocal BM transplantation in lethally irradiated Trpv4+/+ and Trpv4-/- mice as well as using macrophage-deficient op/op mice and transgenic mice expressing the human diphtheria toxin receptor (DTR) in CD11b+ intestinal MΦ (itgam-DTR). Pharmacological and genetic ablation studies will be used to test if TLR4-mediated release of serotonin from mucosal enterochromaffin cells and/or mast cells is required for potentiation of TRPV4-mediated intestinal contractile response by bacterial lipopolysaccharides (LPS). More importantly, a mouse model of POI will be generated to investigate if selective activation of TRPV4 can improve or reverse POI in vivo. Successful completion of these studies will advance our understanding of the previously unrecognized role of TRPV4 and intestinal MΦ in regulating GI motility. More importantly, the proposed studies will define novel therapeutic targets for future clinical studies for the treatment of POI by directly targeting both intestinal innate immune system and the TRPV4 channels.

 描述（由申请方提供）：胃肠道（GI）手术后的术后肠梗阻（POI）导致患者发病率显著增加，住院时间延长。POI是一个主要的健康问题，也是医疗保健系统的重大负担，在美国估计每年为7.5亿至10亿美元。目前，没有治疗方法可以完全成功地减少POI对患者和医疗保健系统的重大影响。近年来的研究表明，肠内操作和手术创伤可激活炎症巨噬细胞（MΦ），释放一氧化氮（NO）等炎症介质，抑制肠平滑肌细胞增殖。因此，抑制免疫功能被认为是治疗POI的有希望的手段。然而，肠道免疫系统的抑制可能会引起严重的副作用，因为肠道免疫系统占整个免疫系统的近70%，并且对免疫稳态至关重要。肠道MΦ是先天免疫系统中高度异质性和动态的群体。初步研究表明，瞬时受体电位香草酸4（TRPV 4）通道是组织损伤和炎症的分子传感器，仅由F4/80+/CD 206+肠道抗炎M2 MΦ表达。在POI小鼠模型中，TRPV 4的激活产生肠收缩反应并改善GI转运。目前的建议旨在阐明TRPV 4在肠道M2 MΦ中激活的细胞和分子机制。本研究将采用钙离子成像和膜片钳技术研究TRPV 4在肠MΦ中的功能。通过在致死性辐照的Trpv 4 +/+和Trpv 4-/-小鼠中相互BM移植以及使用巨噬细胞缺陷型op/op小鼠和在CD 11b+肠MΦ中表达人白喉毒素受体（DTR）的转基因小鼠（itgam-DTR）构建嵌合小鼠，确定TRPV 4介导的收缩反应中骨髓（BM）来源的MΦ的需求。药理学和遗传消融研究将用于测试TLR 4介导的5-羟色胺从粘膜肠嗜铬细胞和/或肥大细胞的释放是否是细菌脂多糖（LPS）增强TRPV 4介导的肠收缩反应所必需的。更重要的是，将产生POI的小鼠模型以研究TRPV 4的选择性活化是否可以改善或逆转体内POI。这些研究的成功完成将促进我们对TRPV 4和肠MΦ在调节GI运动中的先前未被认识的作用的理解。更重要的是，拟议的研究将为未来的临床研究确定新的治疗靶点，通过直接靶向肠道先天免疫系统和TRPV 4通道来治疗POI。