Elucidation of a Eukaryotic Chemorepulsion Mechanism

真核化学脉冲机制的阐明

• 批准号: 10318611
• 负责人: Richard H Gomer
• 金额: $ 36.4万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10318611
• 关键词: Acute Respiratory Distress Syndrome; Agonist; Aspirate substance; Biochemistry; Biological Models; CT2584 HMS; Cells; Cessation of life; Clinic; Clinical; Development; Dictyostelium; Dipeptidyl-Peptidase IV; Disease; Drug Interactions; Eukaryotic Cell; Feedback; Female; G-Protein-Coupled Receptors; Genetic; Genetic Screening; Human; Inflammation; Innate Immune System; Lead; Leukocytes; Lung; Mediating; Modeling; Molecular; Movement; Mus; PAR-2 Receptor; Pathway interactions; Patients; Play; Property; Proteins; Resolution; Rheumatoid Arthritis; Role; Sex Differences; Signal Transduction Pathway; Source; Testing; Therapeutic; Tissues; Varicose Ulcer; Woman; Work; cell motility; decubitus ulcer; diabetic ulcer; insight; lung injury; male; men; mouse model; mutant; neutrophil; receptor; side effect; small molecule

The directed movement of eukaryotic cells away from a source of a chemorepellent appears to play a major role in development and the resolution of inflammation, but very little is known about eukaryotic chemorepellents and how they direct cell motility. Chemorepulsion of Dictyostelium cells from a secreted protein called AprA is a model where one can combine biochemistry and genetics to elucidate chemorepulsion. Using available mutants and a preliminary genetic screen, we identified the AprA receptor, identified several components of the AprA signal transduction pathway, and found that AprA chemorepulsion involves a fundamentally different mechanism from chemoattraction. AprA has predicted structural similarity to the human secreted protein dipeptidyl peptidase IV (DPPIV), and shares functional properties with DPPIV. We found that DPPIV is a chemorepellent for human and mouse neutrophils, found that the G protein-coupled receptor PAR2 mediates DPPIV chemorepulsion, and found that small molecule PAR2 agonists act as neutrophil chemorepellents. Preliminary studies indicate that there are strong similarities between the AprA and PAR2 agonist chemorepulsion mechanisms. Acute respiratory distress syndrome (ARDS) is an untreatable disease involving damage to the lungs causing neutrophils to enter the lungs. The neutrophils further damage the lungs, causing more neutrophil entry in a positive feedback loop, and this results in the death of ~40% of the ~200,000 ARDS patients per year in the US. An exciting insight into a possible therapeutic approach is that when DPPIV or PAR2 agonists are aspirated into the lungs, they induce neutrophils to leave the lungs in two mouse models of ARDS. The key roadblock to moving this into the clinic is that we need to know what the PAR2 agonist chemorepulsion mechanism is to anticipate potential drug interactions and side effects. To gain insights into a fundamental mechanism, and ways to induce neutrophils to leave a tissue, we propose to elucidate the AprA and PAR2 agonist chemorepulsion mechanisms using the power of Dictyostelium to lead the work. We will rigorously test newly identified Dictyostelium chemorepulsion pathway components, and determine where they function in the pathway. We will complete the Dictyostelium genetic screens to gain further insight into chemorepulsion, and then use this information to guide an examination of possibly similar mechanisms in neutrophils. While examining human neutrophil chemorepulsion, we observed a significant difference between male and female neutrophils, and we will delineate the extent and molecular mechanism underlying this difference. Together, the proposed work will elucidate a poorly understood fundamental mechanism, elucidate an unexpected sex difference in the innate immune system, and help elucidate how PAR2 agonists could be used clinically to drive excessive neutrophils out of a tissue, with possibly different treatments for men and women.

真核细胞远离化学防护剂来源的定向运动似乎起到了 在炎症的发育和消退中发挥着重要作用，但人们对真核生物知之甚少 化学驱虫剂及其如何引导细胞运动。来自分泌物的盘基网柄菌细胞的化学脉冲 称为 AprA 的蛋白质是一种模型，可以结合生物化学和遗传学来阐明化学脉冲。 使用可用的突变体和初步的遗传筛选，我们鉴定了 AprA 受体，鉴定了几种 AprA 信号转导途径的组成部分，发现 AprA 化学脉冲涉及 与化学吸引有着根本不同的机制。 AprA 预测了与人类分泌蛋白二肽基肽酶 IV (DPPIV) 的结构相似性， 并与 DPPIV 共享功能特性。我们发现 DPPIV 是人类和小鼠的化学驱避剂 中性粒细胞，发现 G 蛋白偶联受体 PAR2 介导 DPPIV 化学脉冲，并发现 小分子 PAR2 激动剂充当中性粒细胞化学防护剂。初步研究表明，有 AprA 和 PAR2 激动剂化学脉冲机制之间有很强的相似性。 急性呼吸窘迫综合征（ARDS）是一种无法治愈的疾病，涉及肺部损伤 导致中性粒细胞进入肺部。中性粒细胞进一步损害肺部，导致更多的中性粒细胞 进入正反馈循环，这导致每年约 200,000 名 ARDS 患者中约 40% 的死亡 在美国。对可能的治疗方法的一个令人兴奋的见解是，当 DPPIV 或 PAR2 激动剂 在两种 ARDS 小鼠模型中，它们被吸入肺部，诱导中性粒细胞离开肺部。关键 将其推向临床的障碍是我们需要知道 PAR2 激动剂化学脉冲是什么 机制是预测潜在的药物相互作用和副作用。 为了深入了解诱导中性粒细胞离开组织的基本机制和方法，我们 提议利用以下力量阐明 AprA 和 PAR2 激动剂化学脉冲机制 盘基网柄菌来领导工作。我们将严格测试新发现的盘基网柄菌化学脉冲途径 成分，并确定它们在通路中发挥作用的位置。我们将完成盘基网柄菌遗传 筛选以进一步了解化学脉冲，然后使用此信息来指导检查 中性粒细胞中可能有类似的机制。在检查人类中性粒细胞化学排斥时，我们观察到 男性和女性中性粒细胞之间存在显着差异，我们将描述其程度和分子水平 这种差异背后的机制。总之，拟议的工作将阐明一个鲜为人知的问题 基本机制，阐明先天免疫系统中意想不到的性别差异，并帮助 阐明如何在临床上使用 PAR2 激动剂将过量的中性粒细胞驱出组织， 男性和女性的治疗方法可能不同。