INTEGRATIVE AND MOLECULAR STUDIES OF PAIN AND PAIN CONTROL

疼痛和疼痛控制的综合分子研究

• 批准号: 6432046
• 负责人: Michael J. Iadarola
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF DENTAL & CRANIOFACIAL RESEARCH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6432046
• 关键词: Animalia; analgesia; chronic disease /disorder; clinical research; dorsal column; functional magnetic resonance imaging; human subject; neural information processing; neural plasticity; neural transmission; pain

Our research program addresses basic molecular and physiological processes of nociceptive transmission in the central nervous system. The molecular research is performed in animal and in vitro cell-based models. We concentrate on the primary affernt pain sensing neurons and the connections in the dorsal spinal cord. The dorsal spinal cord is the first site of synaptic processing for nociceptive information processing and our research has identified it as a locus of neuronal plasticity and altered gene expression in persistent pain states. Questions related to higher CNS pain processing are performed with humans using in vivo functional brain imaging of chronic pain patients and normal volunteers. The Unit also investigates novel methods for controlling nociceptive transmission and has three novel treatments for sever intractable pain under investigation. Two main basic science issues are being addressed. The first centers on the molecular mechanisms of pain transduction through an investigation of the vanilloid receptor 1. This molecule is a heat-sensitive calcium/sodium ionophore and converts painful heat into nerve action potentials by depolarizing the pain sensing nerve terminals in the skin. Ionophore activity is stimulated by binding of capsaicin a prototypical vanilloid compound and the active ingredient in hot pepper. Point mutations within a unique region in the carboxy end of the molecule suggest the occurrence of separate molecular motifs for thermal and chemical activation. We refer to these as the "heat domain" and "vanilloid domain". This program has directly led to a bench to bedside application in which vanilloid agonists are used to kill pain neurons via ligand-induced calcium cytotoxicity and thereby provide pain control. The second program is centered on gene discovery in spinal cord. Subtraction cloning, sequencing and differential hybridization has revealed new genes enriched in spinal cord and induced by pain stimuli. We are in the process of characterizing the novel genes and placing into context the known genes. These studies have revealed large amounts of new information. For example, we observe dorsal enrichment for a specific phosphorylated subunit of an important inhibitory transmitter, a dorsal enrichment of selected stimulatory and inhibitory modulators of the Rho/Rac cell shape signal transduction pathway, and the induction of expression of two novel genes during persistent experimental pain. This project is a long term, high-risk endeavor, which is setting new directions for molecular pain research. The translational program uses our basic science findings to create new treatments for chronic pain. Three target areas emerged from our bench research. (1) In vivo gene transfer. We are getting the adenoviral-mediated gene transfer of secreted beta-endorphin ready for clinical trial. This involves a CRADA with GenVec, a local gene therapy company, in which the therapeutic cassette is placed into their adenoviral vector and preclinical toxicology is performed. (2) We developed a recombinant cytotoxic toxin-ligand fusion protein called substance P-Pseudomonas exotoxin-35 (SP-PE) as a means to kill spinal cord neurons involved in pain transmission. Complete pain control is achieved by intrathecal administration of as little as15 picomoles of SP-PE. We are currently preparing a large amount of conjugate for preclinical toxicology and clinical trial. (3) We are testing a ultrapotent vanilloid agonist, resiniferatoxin, as a pain control agent for used in removal of primary afferent pain sensing neurons. We developed an intraganglionic injection method. The results of intraganglionic RTX suggest that it will be a very effective approach to control of certain types of chronic pain.

我们的研究项目涉及中枢神经系统中伤害性传递的基本分子和生理过程。分子研究是在动物和体外细胞模型中进行的。我们集中讨论初级传入痛觉神经元和脊髓背侧的连接。脊髓背侧是突触处理痛觉信息的第一个部位，我们的研究已经确定它是持续疼痛状态下神经元可塑性和基因表达改变的一个位点。研究人员利用慢性疼痛患者和正常志愿者的体内功能脑成像技术对人类进行了与高级中枢神经系统疼痛处理有关的问题。该单位还研究控制伤害性传播的新方法，并研究了三种治疗严重难治性疼痛的新方法。两个主要的基础科学问题正在得到解决。第一个中心是通过对香草受体的研究来研究疼痛转导的分子机制。这种分子是一种热敏钙/钠离子，通过使皮肤中的痛觉神经末梢去极化，将痛觉热量转化为神经动作电位。辣椒素是一种典型的香草类化合物，它与辣椒中的活性成分结合，可以刺激离子载体的活性。在分子羧基末端的一个独特区域内的点突变表明存在单独的分子基序进行热活化和化学活化。我们把这些称为“热域”和“香草域”。这个项目直接导致了从实验到临床的应用，香草受体激动剂被用来通过配体诱导的钙细胞毒性杀死疼痛神经元，从而提供疼痛控制。第二个项目的重点是发现脊髓中的基因。减法克隆、测序和差异杂交揭示了在脊髓中富集并受疼痛刺激诱导的新基因。我们正在描述新基因的特征，并将已知基因置于环境中。这些研究揭示了大量的新信息。例如，我们观察到一个重要的抑制性递质的特定磷酸化亚基的背侧富集，Rho/Rac细胞形状信号转导途径的选择性刺激和抑制调节剂的背侧富集，以及在持续实验性疼痛期间诱导两个新基因的表达。该项目是一项长期、高风险的努力，为分子疼痛研究开辟了新的方向。这个转化项目利用我们的基础科学发现来创造治疗慢性疼痛的新方法。我们的实验研究产生了三个目标领域。(1)体内基因转移。我们正在为临床试验准备腺病毒介导的分泌-内啡肽的基因转移。这涉及到与当地基因治疗公司GenVec的CRADA，其中治疗盒被放入他们的腺病毒载体中，并进行临床前毒理学研究。(2)我们开发了一种重组细胞毒性毒素-配体融合蛋白，称为p -假单胞菌外毒素-35 （SP-PE）物质，作为杀死参与疼痛传递的脊髓神经元的手段。完全的疼痛控制是通过鞘内给药15皮摩尔SP-PE实现的。目前我们正在为临床前毒理学和临床试验准备大量的缀合物。(3)我们正在测试一种超强香草素激动剂，树脂干扰素，作为一种疼痛控制剂，用于去除初级传入疼痛感应神经元。我们开发了一种腱鞘内注射方法。神经节内RTX的结果表明，它将是一种非常有效的方法来控制某些类型的慢性疼痛。