Odorant-Receptor Interactions in Olfactory Neurons

嗅觉神经元中的气味受体相互作用

• 批准号: 6942575
• 负责人: THOMAS V GETCHELL
• 金额: $ 28.58万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6942575
• 关键词: apoptosis; biological signal transduction; cell proliferation; chemoreceptors; cytokine receptors; electron microscopy; enzyme linked immunosorbent assay; gene expression; genetically modified animals; immunocytochemistry; in situ hybridization; laboratory mouse; macrophage; macrophage inflammatory proteins; microarray technology; neurogenesis; neurons; olfactory lobe; olfactory nerve; phagocytosis; polymerase chain reaction; protein localization; respiratory epithelium; scavenger receptor; stem cells

DESCRIPTION (provided by applicant): The long-term objective of this project is to investigate intercellular signaling mechanisms that regulate progenitor cell proliferation and neurogenesis in the olfactory epithelium (OE). Short-term, using target ablation to induce neuronal apoptosis followed by a synchronous wave of macrophage activation/infiltration and progenitor cell proliferation, this project focuses on the role of macrophages as sources of bioactive molecules that regulate intercellular signaling. Innovative use of transgenic mice in pilot studies demonstrated that in the absence of activated macrophages, progenitor cell proliferation is substantially reduced following target ablation. The data implicate the chemokine macrophage inflammatory protein (MIP)-1alpha and its receptor CCR1 in macrophage recruitment and suggest that the class A macrophage scavenger receptor (MSR-A) is involved in the clearance of apoptotic neurons, thus linking apoptosis, phagocytosis, cell proliferation, and neurogenesis. The proposed in vivo experiments focus on cellular and molecular events that occur at 2 his to 72 hrs after target ablation, when macrophage infiltration and subsequent signaling is initiated, by addressing three specific aims. The first is to characterize the tune course of mRNA expression for MIP-1alpha and CCR1 following target ablation and to localize their proteins in the OE. The second is to assess the effects of the absence of MIP-1alpha protein in MIP-1alpha-/- mice on macrophage infiltration and progenitor cell proliferation and to determine if the effects can be modulated by exogenous MIP-1alpha protein in knockout mice. The third is to examine the expression of MSR-A as a mediator of phagocytic clearance of apoptotic neurons by macrophages by comparing clearance in wild-type mice and MRS-A-/ mice. Gene profiling methodology will be used in the experiments on knockout mice to examine the involvement of additional chemokine receptors and/or signaling cascades. These studies will elucidate key components of the signaling pathways leading to progenitor cell proliferation and neurogenesis in the OE and establish the use of two new animal models in which to investigate OE cell dynamics in vivo. Understanding the signaling regulating neurogenesis in the OE will yield insights into mechanisms for restoring olfactory function compromised by aging, trauma, and neurodegenerative diseases.

描述（由申请人提供）：该项目的长期目标是研究嗅觉上皮（OE）中调节祖细胞增殖和神经发生的细胞间信号机制。短期内，利用靶消融诱导神经元凋亡，随后巨噬细胞激活/浸润和祖细胞增殖的同步波，本项目重点研究巨噬细胞作为调节细胞间信号的生物活性分子来源的作用。在初步研究中，转基因小鼠的创新应用表明，在缺乏活化巨噬细胞的情况下，靶消融后祖细胞增殖显著减少。这些数据提示趋化因子巨噬细胞炎症蛋白(MIP)-1 α及其受体CCR1参与巨噬细胞募集，并提示A类巨噬细胞清道夫受体（MSR-A）参与凋亡神经元的清除，从而将凋亡、吞噬、细胞增殖和神经发生联系起来。拟建的体内实验主要关注目标消融后2小时至72小时内发生的细胞和分子事件，此时巨噬细胞浸润和随后的信号传导开始，通过解决三个特定目的。首先是表征靶消融后mip -1 α和CCR1 mRNA表达的变化过程，并定位它们在OE中的蛋白。二是评估mip -1 α -/-小鼠中mip -1 α蛋白缺失对巨噬细胞浸润和祖细胞增殖的影响，并确定敲除小鼠中外源性mip -1 α蛋白是否可以调节这种影响。第三，通过比较野生型小鼠和MRS-A-/小鼠的廓清情况，研究巨噬细胞吞噬细胞清除凋亡神经元中MSR-A的表达作为介质的作用。基因谱分析方法将用于基因敲除小鼠的实验，以检查其他趋化因子受体和/或信号级联的参与。这些研究将阐明导致OE中祖细胞增殖和神经发生的信号通路的关键组成部分，并建立两种新的动物模型来研究OE细胞在体内的动力学。了解OE中调节神经发生的信号将有助于了解恢复因衰老、创伤和神经退行性疾病而受损的嗅觉功能的机制。