A Novel Mechanism of Mast Cell-Nerve Interactions in the Esophagus

食管肥大细胞与神经相互作用的新机制

基本信息

批准号：
10093678
负责人：
Xinzhong Dong
金额：
$ 53.08万
依托单位：
JOHNS HOPKINS UNIVERSITY
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：
2020-09-21 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10093678
关键词：
Acids Acute Address Allergens Allergic Attenuated Biopsy Specimen C Fiber Cations Chronic Connective Tissue Cytoplasmic Granules Data Defensins Disease Eosinophil Granule Proteins Eosinophil cationic protein Eosinophilic Esophagitis Epithelial Epithelium Esophageal Diseases Esophagitis Esophagus Functional disorder Funding G-Protein-Coupled Receptors Gastroesophageal reflux disease Genome Heartburn Histology Human IgE Image Immunologics Inflammation Inflammatory Interleukin-5 Intestinal Mucosa Investigation Knowledge Lamina Propria Lead Location Mediating Mediator of activation protein Methodology Modeling Mucous Membrane Mus Nerve Neuroimmune Neurons Neuropeptides Nociception Pain Pathogenesis Peptic Esophagitis Permeability Phenotype Play Proteins Publishing Reaction Reflux Refractory Role Specimen Stratified Squamous Epithelium Substance P Symptoms Techniques Tryptase Wild Type Mouse cytokine eosinophil experimental study extracellular immune activation mRNA Expression mast cell mouse model new therapeutic target novel receptor recruit response tissue injury two-photon

项目摘要

Project Summary Marked increases in esophageal mast cells (MCs) have been identified not only in allergic but also in non-allergic esophageal disorders. At present, their roles in the pathogenesis of those disorders are still less clear. Unlike intestinal mucosal MCs, esophageal MCs are predominantly distributed in the lamina propria of the mucosa, whereas they are matured in non-keratinized stratified squamous epithelium and developed into distinctive phenotype. Recently, the Immunologic Genome (ImmGen) Project Consortium has classified esophageal MC as one of the typical connective tissue MCs. Moreover, our new study has identified that MrgprB2 (the orthologue of human MrgprX2) is a GPCR and exclusively expressed in connective tissue MCs. Many basic secretagogues (substance P, VIP, PAMP, defensins, et al) and eosinophil cationic proteins are now known to activate mast cells exclusively via MrgprB2/X2 mechanisms. Our published and preliminary studies are supporting the novel hypothesis that MrgprB2 (MrgprX2 in human) mediates esophageal inflammation-induced MC activation and directly contributes to esophageal epithelial barrier dysfunction and esophageal afferent nociceptive nerve hyperexcitability. We will address this hypothesis in the mouse and human esophagus with following aims. In Aim 1, we will characterize MrgprB2-positive MCs in healthy and inflamed esophagus with respects to their distribution, phenotype, and activation response (mediators/cytokines release) to basic secrectagogues. We will then address the hypothesis that MrgprB2 mediates non-IgE-dependent MC activation by comparing MC mediator release in inflamed esophagus in wild type and MrgprB2mut mice. Lastly, we will explore, in an eosinophilic esophagitis model, whether eosinophil granule basic proteins (MBP, EPO, END,) directly activate MrgprB2. In Aim 2, we will continue to advance our interesting preliminary data demonstrating that reflux-induced esophageal epithelial barrier dysfunction (increased permeability) is significantly attenuated in MrgprB2 mut mice. To determine if non-MrgprB2 mast cell activation mechanisms also contribute to barrier breakdown we will compare permeability changes in our reflux vs allergic esophagitis models in three groups of mice, wild type mice; mice where the mast cells do not express functional MrgprB2 mut; and thirdly mice that are mast cell deficient. In Aim 3, we will compare the effect of MrgprB2 vs allergen-evoked mast cell activation on esophageal nociceptive C-fiber terminal activities using our well-established extra-cellular recording techniques along with our newly-developed two-photon neuron imaging methodology. In Aim 4, we will compare the expression and function of MrgprX2 in human esophageal biopsy specimens from reflux and eosinophilic esophagitis and then determine their correlations with esophageal histology/symptoms. Translationally, we will briefly characterize MrgprX2 expression and function in mouse esophagus by using our newly-established humanized MrgprX2 mouse line. Clarifying MrgprB2/X2-mediated esophageal mast cell activation may motivate investigation of novel targeted therapeutic strategies for esophageal inflammatory disorders.

项目摘要不仅在过敏性中，而且在非过敏性食管疾病中，已经确定了食管肥大细胞（MC）的明显增加。目前，它们在这些疾病的发病机理中的作用仍然不太清楚。与肠粘膜MC不同，食管MC主要分布在粘膜的固有层中，而它们在非二聚化的分层鳞状上皮中成熟并发展为独特的表型。最近，免疫基因组（IMMGEN）项目联盟已将食管MC归类为典型的结缔组织MC之一。此外，我们的新研究已经确定MRGPRB2（人类MRGPRX2的直系同源物）是GPCR，并且在结缔组织MCS中仅表达。现在已知许多基本的促促囊（物质P，VIP，PAMP，Defensins等）和嗜酸性粒细胞阳离子蛋白可以通过MRGPRB2/X2机制专门激活肥大细胞。我们发表的初步研究支持了新的假设，即MRGPRB2（人类中的MRGPRX2）介导食管炎症引起的MC激活，并直接有助于食管上皮屏障功能障碍和食管食管的吸收性Nocptive Nocptive Noctictive Nectivative Nectivative Nervevive Nervevive Nervevietive。我们将在小鼠和人类食管中解决这一假设。在AIM 1中，我们将在健康和发炎的食道中的MRGPRB2阳性MC相对于其分布，表型和激活反应（介体/细胞因子释放），以构成基本的秘密。然后，我们将解决以下假设：MRGPRB2通过比较野生型和MRGPRB2MUT小鼠中发炎的食管中的MC介质释放来介导非IGE依赖性MC激活。最后，我们将在嗜酸性食管炎模型中探索嗜酸性粒细胞颗粒碱性蛋白（MBP，EPO，END）是否直接激活MRGPRB2。在AIM 2中，我们将继续进步我们有趣的初步数据，表明Replux诱导的食管上皮屏障功能障碍（渗透率增加）在MRGPRB2 MUT小鼠中显着减弱。为了确定非MRGPRB2肥大细胞活化机制是否也有助于屏障崩溃，我们将比较三组小鼠（野生型小鼠）反流与过敏性食管炎模型的渗透性变化；肥大细胞不表达功能性MRGPRB2 mut的小鼠；第三小鼠是肥大细胞缺陷的小鼠。在AIM 3中，我们将使用我们良好的细胞外记录技术以及我们新近开发的两光子Neuron Imaging方法的方法比较MRGPRB2与过敏原诱发的肥大细胞激活对食管伤害感受的C纤维末端活性的影响。在AIM 4中，我们将比较MRGPRX2在反流和嗜酸性食管炎的人类食管活检标本中的表达和功能，然后确定它们与食管组织学/症状的相关性。在翻译上，我们将通过使用我们新建立的人源化MRGPRX2小鼠系来简要表征小鼠食道中MRGPRX2的表达和功能。澄清MRGPRB2/X2介导的食管肥大细胞激活可能会激发对食管炎性疾病的新型靶向治疗策略的研究。