Roles of novel MRGPRX2/MrgprB2 signaling in mast cells on host defense and Inflammation

肥大细胞中新型 MRGPRX2/MrgprB2 信号传导在宿主防御和炎症中的作用

基本信息

批准号：
10062477
负责人：
Hydar Ali
金额：
$ 40.55万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-12-01 至 2024-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10062477
关键词：
Adaptor Signaling Protein Affinity Agent 48-80 Agonist Allergic Arrestins Bacterial Infections Binding Proteins Biological CRISPR/Cas technology Cell Degranulation Cell Line Cell Surface Receptors Cell physiology Cell surface Chronic Clinical Connective Tissue Coupling Data Disease FDA approved G-Protein-Coupled Receptors GTP-Binding Proteins Generations Host Defense Human Hypersensitivity IgE Receptors In Vitro Inflammation Inflammatory Knock-in Knock-in Mouse Ligand Binding Ligands Mediating Mediator of activation protein Modification Molecular Mus Mutation Natural Immunity Neuropeptide Receptor Neuropeptides Neutrophil Infiltration Opioid Opioid Receptor Pathogenesis Pathway interactions Peptides Pharmaceutical Preparations Phenotype Play Procedures Pruritus Reaction Regulation Role Rosacea Signal Pathway Signal Transduction Structure Substance P Urticaria Variant Wild Type Mouse adaptive immunity antimicrobial peptide antimicrobial peptide LL-37 base beta-arrestin chemokine chronic inflammatory skin cytokine desensitization exome sequencing gain of function in vivo loss of function mast cell molecular modeling molecular sequence database mutant novel novel strategies pituitary adenylate cyclase activating polypeptide receptor receptor coupling receptor expression receptor function recruit response side effect skin disorder transcription factor

项目摘要

Summary: In addition to the high affinity IgE receptor (FcεRI), human connective tissue mast cells (MCTC) express a recently described G protein coupled receptor (GPCR), known as Mas-related GPCR-X2 (MRGPRX2). Our lab was the first to demonstrate that host defense antimicrobial peptides (HDPs) activate human mast cells via MRGPRX2, which likely contributes to innate immunity. Emerging evidence suggests that MRGPRX2- mediated local mast cell activation clears bacterial infection via the recruitment of neutrophils and promotes adaptive immunity to control reinfection. However, dysregulation of host defense and excessive generation of the host defense peptide, LL-37 contributes to the pathogenesis of rosacea. MrgprB2 is the mouse counterpart of human MRGPRX2 and our preliminary data demonstrated that LL-37-mediated experimental rosacea is significantly reduced in MrgprB2-/- mice when compared to wild-type mice. MRGPRX2 also serves as a novel GPCR for neuropeptides such as substance P, hemokinin-1 and pituitary adenylate cyclase- activating peptide (PACAP). Furthermore, MRGPRX2 is an “atypical opioid receptor” and some of the side effects opioids are likely mediated via mast cell degranulation through this receptor. However, the molecular mechanisms involved in the activation and regulation of its downstream signaling remains largely unknown. In addition to G proteins, many GPCR agonists also signal via the recruitment of adapter proteins known as β-arrestins. This pathway not only contributes to GPCR desensitization but also provides a platform for a variety of G protein-independent signaling. Biased GPCR agonists preferentially activate pathways mediated by G proteins (G protein-biased) or β-arrestins (β-arrestin-biased). Agonists that activate both pathways are known as balanced agonists. Recently, we made the surprising observation that while compound 48/80 activates both G protein and β-arrestin (balanced agonist) an angiogenic host defense peptide activates only G protein but not β-arrestin (G protein-biased agonist). Based on these findings, we hypothesize that balanced and G protein-biased MRGPRX2 agonists activate mast cells via different mechanisms to promote distinct biological responses in vivo. Because MrgprB2 is the mouse counterpart of the human MRGPRX2, we will incorporate this receptor for many of our in vivo studies. In aim #1, we will determine which of the known mast cell secretagogues (HDPs, neuropeptides, opioids and FDA-approved pseudo-allergic drugs) act as balanced and G protein-biased agonists for MRGPRX2. We will also identify the structural determinants on the receptor that facilitate their coupling to G protein and β-arrestins. In aim #2, we will modulate host defense, pseudo-allergy and rosacea by targeting MRGPRX2/MrgprB2’s balanced/G protein biased signaling in mast cells in vivo. In aim #3, we will determine the roles of β-arrestin1 and β-arrestin2 on MRGPRX2 and MrgprB2-mediated signaling in vitro and biological responses in vivo. Completion of this study will provide novel approaches to modulate MRGPRX2-mediated host defense and inflammatory diseases.

概括：除了高亲和力IgE受体（FCεRI）之外，人相连的组织肥大细胞（MCTC）表达最近描述的G蛋白偶联受体（GPCR），称为MAS相关的GPCR-X2（MRGPRX2）。我们的实验室是第一个证明宿主防御抗菌胡椒粉（HDP）激活人类肥大细胞的人通过MRGPRX2，可能有助于先天免疫。新兴的证据表明MRGPRX2- 介导的局部肥大细胞激活通过募集中性粒细胞清除细菌感染并促进自适应控制改革。但是，主机防御和过度产生的失调在宿主防御肽中，LL-37有助于酒渣鼻的发病机理。 MRGPRB2是鼠标人MRGPRX2和我们的初步数据表明LL-37介导的实验表明与野生型小鼠相比，MRGPRB2 - / - 小鼠的酒渣鼻显着降低。 MRGPRX2也提供服务作为一种用于神经肽的新型GPCR，例如PESSS P，炎性蛋白1和腺苷酸循环 - 激活肽（PACAP）。此外，MRGPRX2是“非典型阿片受体”，有些侧面效应可能是通过该受体通过肥大细胞脱粒来介导的。但是，分子其下游信号传导激活和调节涉及的机制在很大程度上未知。除G蛋白外，许多GPCR激动剂还通过募集衔接蛋白发出信号称为β-arrestin。该途径不仅有助于GPCR脱敏，而且还提供了一个平台用于多种与G蛋白质无关的信号传导。偏见的GPCR激动剂优先激活途径由G蛋白（G蛋白偏置）或β-arre蛋白（β-arrestin偏置）介导。激活两者的激动剂途径被称为平衡激动剂。最近，我们做出了令人惊讶的观察，虽然复合 48/80激活G蛋白和β-甲蛋白（平衡激动剂）血管生成宿主防御肽激活只有G蛋白，而不是β-arrestin（G蛋白偏置激动剂）。基于这些发现，我们假设平衡和G蛋白偏向的MRGPRX2激动剂通过不同的机制激活肥大细胞在体内促进不同的生物学反应。因为MRGPRB2是人类的小鼠 MRGPRX2，我们将在许多体内研究中纳入该受体。在AIM＃1中，我们将确定哪个已知的肥大细胞促分子（HDP，神经肽，阿片类药物和FDA批准的伪过敏性药物）作为MRGPRX2的平衡和G蛋白偏置激动剂。我们还将确定结构接收器上的决定因素促进其与G蛋白和β-arrestin的耦合。在AIM＃2中，我们将通过针对MRGPRX2/MRGPRB2的平衡/G蛋白来调节宿主防御，伪过敏和酒渣鼻体内肥大细胞中的偏置信号传导。在AIM＃3中，我们将确定β-arrestin1和β-arrestin2在 MRGPRX2和MRGPRB2介导的体外信号传导在体内的体外和生物学反应。这项研究的完成将提供新颖的方法来调节MRGPRX2介导的宿主防御和炎症性疾病。