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在愈合时保护受损组织的机制。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。这种敏感性可以表现为对先前非伤害性刺激的厌恶性退缩（异常性疼痛）。尽管它的生物学和临床的重要性，伤害性敏化所需的基因仍然不清楚。该研究项目的重点是在一个模型遗传生物体中的伤害性致敏的分子遗传控制，其中基因的发现非常方便。我们的指导假设是，有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，我们已经建立了一个伤害性致敏试验，使用果蝇幼虫，并证明了发展的热异常性疼痛需要果蝇同源的肿瘤坏死因子（TNF）受体和其他17个基因，我们在致敏突变体的遗传筛选确定。对于该筛选，我们测试了在伤害性感觉神经元中特异性表达基因特异性抑制性RNAi转基因的幼虫是否可以在屏障表皮的UV照射后正常地发展异常性疼痛。我们的长期目标是使用我们独特的检测方法和遗传工具来鉴定伤害性感觉神经元中发生异常性疼痛所需的基因的互补，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：1.检验物理组织损伤（创伤）通过与UV诱导的组织损伤不同的信号和介质诱导异常性疼痛的假设。2.为了检验UV照射后TNF诱导是非依赖性的、转录的和/或翻译/翻译后的假设。三。通过扩大我们的遗传筛选来表征和鉴定伤害性致敏所需的新基因。该项目代表了在模型遗传生物中对伤害性敏化的第一次系统研究，并且具有发现启动、执行和调节该过程的基因的巨大潜力。考虑到最基本的神经元功能所需的基因的保守性，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）中的伤害性敏化的理解，其中这种形式的感觉神经元可塑性被认为是不适当的激活或调节。 公共卫生相关性：该研究项目采用了一种模式遗传生物果蝇，以揭示伤害性（疼痛）致敏的遗传控制，这是一个与人类健康直接相关的过程。伤害性致敏对于生物体在愈合时保护组织损伤部位（例如由创伤或手术引起的组织损伤部位）至关重要。考虑到大多数基本生物过程（包括神经元功能）所需的基因保守性，我们预计该项目将告知我们对脊椎动物和病理生理状态（如癌症和各种慢性疼痛综合征）中伤害性致敏的理解，其中致敏反应被认为是不适当的激活或调节。

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. PUBLIC HEALTH RELEVANCE: This research project employs a model genetic organism, the fruit fly, to uncover the genetic control of nociceptive (pain) sensitization, a process of immediate relevance to human health. Nociceptive sensitization is critical for organisms to protect sites of tissue injury, such as those caused by trauma or surgery, while they heal. Given the conservation of genes required for most fundamental biological processes, including neuronal function, we expect that this project will inform our understanding of nociceptive sensitization in vertebrates and in pathophysiological states, such as cancer and a variety of chronic pain syndromes, where the sensitization response is thought to be improperly activated or regulated.