A genetically tractable model of tissue damage-induced nociceptive sensitization

描述（由申请人提供）：多细胞生物已经进化出保护受损组织愈合的机制。其中一种机制是感觉神经元可塑性的一种形式，称为伤害性敏化。这种致敏可表现为对先前无害刺激（异常性疼痛）的厌恶性戒断。尽管它具有生物学和临床重要性，但伤害性致敏所需的基因仍然不清楚。本研究项目的重点是在一种模式遗传生物中对伤害性致敏的分子遗传控制，从而极大地促进了基因发现。我们的指导假设是，存在一个保守的分子遗传机制，启动、调节、执行和终止伤害性敏化。为了验证这一假设，我们利用果蝇幼虫建立了一项伤害性致敏实验，并证明了热异常性痛的发展需要果蝇肿瘤坏死因子（TNF）受体的同源基因和我们在致敏突变基因筛选中发现的其他17个基因。为了进行筛选，我们测试了在伤害感觉神经元中表达基因特异性抑制RNAi转基因的幼虫在紫外线照射屏障表皮后是否能正常发生异常性痛觉。我们的长期目标是利用我们独特的检测方法和遗传工具来鉴定异常性疼痛发育中伤害性感觉神经元所需的基因补体，并确定这些基因在致敏过程中的特定功能。我们的短期目标列举在以下具体目标中：为了验证物理组织损伤（损伤）与紫外线诱导的组织损伤相比，通过不同的信号和介质诱导异常性痛的假设。2. 为了验证紫外线照射后TNF诱导与凋亡无关、转录和/或翻译/翻译后的假设。, 3。通过扩大我们的基因筛选来描述和鉴定伤害性敏化所需的新基因。该项目代表了对模型遗传生物中伤害性致敏的第一个系统研究，并具有揭示启动、执行和调节这一过程的基因的巨大潜力。鉴于大多数基本神经元功能所需的基因保存，我们期望该项目将告知我们对脊椎动物和病理生理状态（如癌症和慢性疼痛综合征）的伤害性敏化的理解，在这些状态下，这种形式的感觉神经元可塑性被认为是不正确激活或调节的。

DESCRIPTION (provided by applicant): Multicellular organisms have evolved mechanisms to protect damaged tissue while it heals. One mechanism is a form of sensory neuron plasticity called nociceptive sensitization. This sensitization can manifest as aversive withdrawal to previously non- noxious stimuli (allodynia). Despite its biological and clinical importance, the genes required for nociceptive sensitization remain obscure. This research project focuses on the molecular genetic control of nociceptive sensitization in a model genetic organism where gene discovery is greatly facilitated. Our guiding hypothesis is that there is a conserved molecular genetic machinery that initiates, regulates, executes, and terminates nociceptive sensitization. To test this hypothesis we have established a nociceptive sensitization assay using Drosophila larvae and demonstrated that development of thermal allodynia requires the Drosophila homolog of the tumor necrosis factor (TNF) receptor and seventeen other genes we identified in a genetic screen for sensitization mutants. For this screen we tested whether larvae expressing gene-specific inhibitory RNAi transgenes specifically in nociceptive sensory neurons could develop allodynia normally following UV irradiation of the barrier epidermis. Our long-term objective is to use our unique assays and genetic tools to identify the complement of genes required in nociceptive sensory neurons for development of allodynia and to determine the specific function of these genes during sensitization. Our shorter-term goals are enumerated in the following specific aims: 1. To test the hypothesis that physical tissue damage (wounding) induces allodynia through different signals and mediators than UV-induced tissue damage. 2. To test the hypotheses that TNF induction following UV irradiation is apoptosis-independent, transcriptional, and/or translational/post-translational. And, 3. To characterize and identify novel genes required for nociceptive sensitization by expanding our genetic screen. This project represents the first systematic study of nociceptive sensitization in a model genetic organism and has great potential for uncovering the genes that initiate, execute, and regulate this process. Given the conservation of genes required for most fundamental neuronal functions we expect that this project will inform our understanding of nociceptive sensitization in vertebrates and in pathophysiological states, such as cancer and chronic pain syndromes, where this form of sensory neuron plasticity is thought to be improperly activated or regulated.