Neuroinflammatory Regulation of Colonic Mechanosensory Activity

结肠机械感觉活动的神经炎症调节

基本信息

批准号：
10395490
负责人：
Liya Qiao
金额：
$ 34.93万
依托单位：
VIRGINIA COMMONWEALTH UNIVERSITY
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：
2019-07-01 至 2024-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10395490
关键词：
Ablation Afferent Neurons Affinity Affinity Chromatography Animals Behavior assessment Brain-Derived Neurotrophic Factor Cells Clinical Colon Colony-Stimulating Factor Receptors Colony-Stimulating Factors Colorectal Disease Distal Female Fluorescence-Activated Cell Sorting Gender Genetic Goals Human Hypersensitivity Image Imaging Techniques Immune In Vitro Inflammatory Intestines Irritable Bowel Syndrome Knockout Mice Macrophage Colony-Stimulating Factor Measurement Measures Mechanics Mediating Mediation Mediator of activation protein Modeling Modification Mus Neuroglia Neurons Neurotrophic Tyrosine Kinase Receptor Type 2 Nociception Nociceptors Pain Patients Piezo 2 ion channel Production Protein Isoforms Prothrombin Regulation Ribosomes Role Sensory Spinal Ganglia System TNF gene Translating Triad Acrylic Resin base cell type colorectal distension conditional knockout cytokine design gastrointestinal in vivo insight macrophage male mechanotransduction neurochemistry neuroinflammation receptor response sex sexual dimorphism tool treatment strategy

项目摘要

PROJECT SUMMARY The enhanced colorectal mechanosensation in colonic hypersensitivity and gastrointestinal (GI) pain is initiated and mediated by primary afferent neurons in dorsal root ganglia (DRG), perhaps by Piezo2-mediated mechanotransduction in a subpopulation of colonic nociceptive afferent neurons. Macrophage colony- stimulating factor (CSF1) and brain-derived neurotrophic factor (BDNF) are two potent mediators in the genesis of mechanical pain, however, DRG nociceptive neurons do not express CSF1 receptor Csf1r and few neurons have BDNF receptor TrkB. Macrophages and glial cells including satellite glial cells (SGCs) express Csf1r and/or TrkB isoforms, therefore they are likely primary recipients of CSF1 and BDNF. In DRG, macrophages and glial cells surround sensory neurons to form a neuronal-glial-immune cell triad. Upon activation, macrophages and glial cells release a variety of inflammatory factors such as the pronociceptive cytokine tumor necrosis factor alpha (TNFα) that can act on nearby sensory neurons. In our preliminary study, macrophages and glial cells act differentially in producing TNFα in DRG of male and female mice in colonic hypersensitivity models. TNFα and CSF1-conditioned human macrophage culture medium activate a subset of Piezo2 expressing colonic afferent neurons. Macrophages are also activated by BDNF to produce TNFα. We postulate that macrophages and glial cells are activated by CSF1 and BDNF in DRG to generate TNFα that activates Piezo2 expressing colonic afferent neurons, leading to colonic mechanosensory sensitization. We will pursue three interrelated Specific Aims. In AIM 1, we will distinguish the roles of macrophages and glial cells in producing TNFα to generate neuroinflammation in DRG in male and female mice to regulate colonic hypersensitivity. We will implement genetic tools for conditional ablation/inhibition of macrophages or glial cells, and examine colorectal distension (CRD)-evoked mechanosensory activity by in vivo DRG imaging. In AIM 2, we will determine Piezo2 in DRG nociceptive neurons in mediation of neuroinflammatory regulation of colonic hypersensitivity. We will use our Piezo2 conditional knockout mouse line to perform direct neurochemical measurement and study the functional roles of Piezo2 in mediation of neuroinflammation (TNFα)-regulated colonic mechanosensory activity. In AIM 3, we will characterize the regulation of macrophages and glial cells by CSF1 and BDNF in male and female mice in producing TNFα to regulate Piezo2 expressing colonic afferent neurons. In many species and systems, the expression of TrkB receptors is sex-related. We will examine whether TrkB receptors are sexually dimorphic in macrophages and glial cells to interpret the distinct roles of macrophages and glial cells in colonic hypersensitivity in male and female mice, and suggest mechanism of gender-related GI pain in patients. Our studies using in vivo, in vitro, genetic tools, and imaging techniques in characterizing the impact of neuroinflammation on colonic mechanosensory activity will open new avenues in designing specific target(s) in the treatment of GI pain and functional bowel disorders.

项目概要结肠过敏和胃肠道（GI）疼痛中结直肠机械感觉的增强是由背根神经节 (DRG) 的初级传入神经元发起和介导，可能是由 Piezo2 介导的结肠伤害性传入神经元亚群的机械转导。刺激因子（CSF1）和脑源性神经营养因子（BDNF）是两个有效的介质然而，DRG 伤害性神经元不表达 CSF1 受体 Csf1r，并且很少表达机械性疼痛的发生神经元具有 BDNF 受体 TrkB 表达，巨噬细胞和神经胶质细胞（包括卫星神经胶质细胞 (SGC)）表达。 Csf1r 和/或 TrkB 同工型，因此它们可能是 DRG 中 CSF1 和 BDNF 的主要受体。巨噬细胞和神经胶质细胞包围感觉神经元，形成神经元-神经胶质-免疫细胞三联体。激活后，巨噬细胞和神经胶质细胞释放多种炎症因子，如促伤害感受因子在我们的初步研究中，可以作用于附近感觉神经元的细胞因子肿瘤坏死因子α（TNFα）。结肠中雄性和雌性小鼠 DRG 中巨噬细胞和神经胶质细胞在产生 TNFα 方面的作用存在差异超敏反应模型中，TNFα 和 CSF1 条件的人巨噬细胞培养基激活了一部分表达 Piezo2 的结肠传入神经元也被 BDNF 激活以产生 TNFα。假设巨噬细胞和神经胶质细胞被 DRG 中的 CSF1 和 BDNF 激活，产生 TNFα，激活表达 Piezo2 的结肠传入神经元，导致结肠机械感觉敏化。追求三个相互关联的具体目标在 AIM 1 中，我们将区分巨噬细胞和神经胶质细胞的作用。产生 TNFα，在雄性和雌性小鼠的 DRG 中产生神经炎症，从而调节结肠我们将使用遗传工具来有条件地消融/抑制巨噬细胞或神经胶质细胞，在 AIM 2 中，通过体内 DRG 成像观察颜色检查直肠扩张 (CRD) 诱发的机械感觉活动。我们将确定 DRG 伤害性神经元中的 Piezo2 在介导结肠神经炎症调节中的作用我们将使用我们的 Piezo2 条件敲除小鼠系进行直接神经化学研究。测量和研究 Piezo2 在介导神经炎症 (TNFα) 调节中的功能作用在 AIM 3 中，我们将描述巨噬细胞和神经胶质细胞的调节。通过雄性和雌性小鼠中的 CSF1 和 BDNF 产生 TNFα 来调节表达 Piezo2 的结肠传入在许多物种和系统中，TrkB 受体的表达与性别相关。 TrkB 受体在巨噬细胞和神经胶质细胞中是否存在性别二态性，以解释 TrkB 受体的不同作用巨噬细胞和神经胶质细胞在雄性和雌性小鼠结肠过敏中的作用，并提出了机制我们使用体内、体外、遗传工具和成像技术对患者进行性别相关的胃肠道疼痛研究。表征神经炎症对结肠机械感觉活动的影响将为研究开辟新途径设计治疗胃肠道疼痛和功能性肠道疾病的具体目标。