Integrative And Molecular Studies Of Pain And Pain Control

疼痛和疼痛控制的综合和分子研究

• 批准号: 8344127
• 负责人: Michael J. Iadarola
• 金额: $ 96.16万
• 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/8344127
• 关键词: Action Potentials; Acute Pain; Address; Advanced Malignant Neoplasm; Africa; Agonist; Amputation; Analgesics; Animals; Area; Arthralgia; Autopsy; Axon; Axotomy; Behavior; Behavioral; Binding; Biological; Bladder; Body Regions; Brain; Breakthrough Pain; C Fiber; Cactaceae; Calcium; Cancer Patient; Capsaicin; Cells; Cerebrospinal Fluid; Cervical spinal cord structure; Cessation of life; Chemicals; Clinical Protocols; Clinical Trials; Collaborations; Collection; Complex; Cornea; Coupled; Cultured Cells; Degenerative polyarthritis; Dihydropyridines; Dorsal; Dose; Drug abuse; Electrophysiology (science); Epilepsy; Esthesia; Evaluation; Event; Fiber; Gene Expression; Gene Expression Profile; Gene Expression Regulation; Generic Drugs; Genes; Goals; Head and Neck Cancer; Heating; Human; Image; In Vitro; Indium; Inflammation; Intervention; Intestines; Intractable Pain; Investigation; Investigational New Drug Application; Ion Channel; Ions; Joints; Knowledge; Lasers; Latex; Lead; Lesion; Libraries; Ligands; Malignant Neoplasms; Mechanics; Mediator of activation protein; Methods; Modeling; Modification; Molecular; Molecular Bank; Molecular Probes; Motor; National Institute of Mental Health; Natural regeneration; Nerve; Nerve Endings; Nerve Fibers; Neurobiology; Neuronal Plasticity; Neurons; Neuropathy; Nociception; Pain; Pain Disorder; Pain management; Pathway interactions; Patients; Pattern; Peripheral; Peripheral Nerves; Peripheral Nervous System; Persistent pain; Pharmaceutical Chemistry; Phase I Clinical Trials; Physiological; Physiological Processes; Plants; Postherpetic neuralgia; Pre-Clinical Model; Preparation; Process; Proprioception; Protein Analysis; Protocols documentation; Ranvier' s Nodes; Regulation; Research; Resiniferatoxin; Role; Route; Safety; Sampling; Screening procedure; Sensory; Signal Transduction; Site; Skin; Sodium Channel; Specificity; Spinal; Spinal Cord; Spinal Ganglia; Stimulus; Structure; Structure of trigeminal ganglion; Synapses; Synaptic Transmission; Synaptic plasticity; System; TRPV1 gene; Therapeutic; Time; Tissues; Touch sensation; Transducers; Translational Research; Universities; Validation; Vanilloid; afferent nerve; analog; base; cancer pain; cell injury; chronic pain; combinatorial; cytotoxicity; dihydropyridine; inflammatory pain; information processing; injured; killings; meetings; millisecond; nerve injury; nervous system disorder; neuropathology; novel; novel strategies; painful neuropathy; phase 1 study; pressure; programs; receptor; repaired; response; small molecule; small molecule libraries; translational study; transmission process; uptake; vanilloid receptor subtype 1; vibration

Summary: Overview: This research program addresses basic molecular and physiological processes of nociceptive (pain-sensing) transmission in the central and peripheral nervous systems and new ways to effectively control pain. The molecular research is performed using animal and in vitro, cell-based models. We concentrate on primary afferent pain-sensing neurons located in dorsal root ganglion (DRG) that innervate the skin and deep tissues and their connections in the dorsal spinal cord, which is the first site of synaptic information processing for pain. Our research has identified the DRG and spinal cord as loci of neuronal plasticity and altered gene expression in persistent pain states. The mechanisms of transduction of physical pain stimuli are investigated through examination of events and molecules in damaged or inflamed peripheral tissue, in primary cultures or using reductionist preparations such as heterologous expression systems in cultured cells. Our goals are (1) to understand the molecular and cell biological mechanisms of acute and chronic pain at the initial steps in the pain pathway, (2) to investigate mechanisms underlying human chronic pain disorders, and (3) to use this knowledge to devise new treatments for pain. New Treatments for Pain: We address the new treatment goal by a translational research and human clinical trials program aimed at developing new analgesics and interventions for severe pain. The current approach, based on our studies of pain transduction through the vanilloid transient receptor potential ion channel (TRPV1), has resulted in a Phase I clinical trial of the TRPV1 agonist resiniferatoxin (RTX) as a new treatment for advanced cancer pain. RTX activates TRPV1, which is an inflammation and heat-sensitive calcium/sodium ion channel that normally converts painful heat or low pH into nerve action potentials by opening the pore of the ion channel. The influx of ions depolarizes pain-sensing nerve endings and triggers electrical impulses that are conducted to the spinal cord. RTX is a potent capsaicin analog that props open the TRPV1 ion channel, causing calcium cytotoxicity and death of TRPV1 pain-sensing neurons or their axonal projections or endings. RTX treatments produced very effective pain control in preclinical models by several routes of administration: into the cerebrospinal fluid around the spinal cord (intrathecal) or directly into the sensory dorsal root ganglion (DRG) (permanent effect) or into peripheral sites to expose nerve endings in skin, joints, cornea or axons in a peripheral nerve (temporary effect since the peripheral endings regenerate). To date, following approval of the clinical protocol and the Investigational New Drug application, we have treated 5 patients with severe pain from advanced cancer and went through one dose escalation. The aim of the Phase I study is to determine the safety of RTX upon administration into the spinal CSF (intrathecal). Our plan is to complete the Phase I study, generate new protocols for postherpetic neuralgia an other acute and chronic pain conditions such as osteoarthritis, head and neck cancer, post-amputation and neuropathic pain. Basic Pain Mechanisms: Underlying the translational studies are investigations of molecular regulation of gene expression, neuronal function, behavior, and mechanisms of pain transduction. We are systematically investigating the first three steps in the pain pathway beginning with injured peripheral tissue, the dorsal root ganglion and the dorsal (sensory) spinal cord. The goal of this approach is to obtain a comprehensive molecular understanding of nociceptive process. Our studies reveal a complex, dynamic modulation of gene expression at all three steps. We have identified prominent roles for new, key molecules with distinct combinatorial patterns of expression among the three tissues. We are now examining human DRG and spinal cord to determine if the same expression and enrichment occurs in human pain circuits. We established collaboration with the Neuropathology Section, NIMH and have collected over 100 human trigeminal ganglia and cervical spinal cord samples. These tissues are being used for transcriptome and protein analysis of human nociceptive circuits. We are in the process of establishing collaboration with Rush University to obtain postmortem DRG and spinal cord of patients with defined pain disorders; thus both baseline and pain-state-dependent changes can be investigated. Through this research we hope to obtain a fundamental understanding of the relationships between tissue damage, inflammation and pain sensation. In a broader framework, these studies explore the fundamental molecular basis of synaptic plasticity. We hypothesize modularity in neuronal responses when a new level of synaptic or pharmacological input occurs that will be relevant to pain, and to neurological disorders like epilepsy or drug abuse whereby "generic" alterations are combined with circuit-specific genes to meet the demands of new stimulation or activity. Understanding the molecular repertoire and its dynamic interactions will lead to a deeper understanding of mechanisms that trigger and sustain chronic pain and other disorders of the nervous system. In terms of behavioral studies, we have begun to dissect out the role of the lightly myelinated, rapidly conducting A-delta neuron using an infrared diode laser stimulator. These studies show that A-delta neurons are sensitized in inflammatory pain, similar to C-fibers, and have led to the hypothesis that they are mediators or triggers for breakthrough pain in osteoarthritis or cancer. We also have determined that the A-delta fibers are the most sensitive to RTX axotomy, possibly because the lesion occurs at multiple nodes of Ranvier that the cell cannot repair easily. We shall be examining this issue in more detail. Becauese the stimulus is so short this allows for detailed studies of sensory motor integration in the first few milliseconds after stimulation,before compensatory pain control processes can intervene. These types of fast transient stimuli are often the stimuli that trigger episodes of breakthrough pain. Early Translational Investigations: A final set of studies concerns the identification of small chemicals that act as positive allosteric modulators (PAMs) of TRPV1 activation by pH or vanilloid agonists. Our human cancer study showed that TRPV1 is one of the most important transducers of painful stimuli and understanding how the ion channel can be blocked, activated or sensitized is fundamental to understanding pain. We have identified a new action on TRPV1 via screening of small molecule libraries. We discovered compounds that enhance the activation of TRPV1 upon agonist binding to the orthosteric site or by elevated H+ ions. These studies suggest allosteric modulation of the TRPV1 ion channel open state that may be accessed for pain transmission as well as the existence of a new class of pharmacological agents for pain modulation and pain control. Over the past year we screened the 300,000 compound Molecular Probes library and identified over 100 direct agonists and over 900 PAMs. Clearly not all of these single-point determinations are correct and we are in the process of rescreening for validation. Secondary screens for specificity will use other TRP and ligand activated ion channels coupled with electrophysiological recordings and Ca-45 uptake. We hope to obtain new probes for TRPV1 functional studies and new leads for PAMs that can be used for pain control. These studies have progressed to the point where we are synthesizing analogs of the lead PAMs for evaluation.

摘要：概述：该研究计划介绍了中央和周围神经系统中伤害感受（疼痛）传播的基本分子和生理过程，以及有效控制疼痛的新方法。分子研究是使用动物和基于细胞的体外模型进行的。我们集中于位于背根神经节（DRG）中的一级传入疼痛神经元，该神经元（DRG）支配了皮肤和深层组织及其在背脊髓中的连接，这是疼痛的突触信息处理的第一个部位。我们的研究将DRG和脊髓确定为神经元可塑性的基因座，并改变了持续性疼痛状态的基因表达。通过检查受损或发炎的外周培养物中的事件和分子，原代培养物中的事件和分子的转导机制，或使用还原主义的制剂，例如培养细胞中的异源表达系统。我们的目标是（1）了解疼痛途径初始步骤下急性和慢性疼痛的分子和细胞生物学机制，（2）研究人类慢性疼痛障碍的机制，以及（3）使用这些知识来设计新的疼痛治疗方法。 疼痛的新治疗方法：我们通过翻译研究和人类临床试验计划来解决新的治疗目标，旨在开发新的镇痛药和干预措施以实现严重疼痛。基于我们对通过香草素瞬态受体电位离子通道（TRPV1）进行疼痛转导的研究的研究，导致了TRPV1激动剂树脂毒素（RTX）的I期临床试验，作为晚期癌症疼痛的新方法。 RTX激活TRPV1，这是一种炎症和热敏感的钙/钠离子通道，通常通过打开离子通道的孔，将疼痛的热或低pH值转化为神经作用电位。离子的流入使疼痛感应的神经末端去极化，并触发向脊髓进行的电脉冲。 RTX是一种有效的辣椒素类似物，可以打开TRPV1离子通道，导致TRPV1疼痛感应神经元或其轴突投射或结尾的钙细胞毒性和死亡。 RTX treatments produced very effective pain control in preclinical models by several routes of administration: into the cerebrospinal fluid around the spinal cord (intrathecal) or directly into the sensory dorsal root ganglion (DRG) (permanent effect) or into peripheral sites to expose nerve endings in skin, joints, cornea or axons in a peripheral nerve (temporary effect since the peripheral endings regenerate).迄今为止，在临床方案和研究新药应用的批准后，我们​​已经治疗了5例患有晚期癌症的严重疼痛患者，并进行了一次剂量升级。 I期研究的目的是确定RTX在脊柱CSF（鞘内）施用时的安全性。我们的计划是完成I阶段研究，生成针对后神经痛的新方案，另一种急性和慢性疼痛疾病，例如骨关节炎，头颈癌，肿瘤后和神经性疼痛。 基本疼痛机制：基础研究是对基因表达，神经元功能，行为和疼痛转导机制的分子调节的研究。我们正在系统地研究疼痛途径的前三个步骤，从受伤的周围组织，背根神经节和背脊髓（感觉）脊髓开始。这种方法的目的是获得对伤害性过程的全面分子理解。 我们的研究揭示了在所有三个步骤上对基因表达的复杂，动态调节。我们已经确定了新的关键分子的突出作用，在这三个组织中具有不同的表达组合模式。我们现在正在检查人类DRG和脊髓，以确定在人类疼痛电路中是否发生相同的表达和富集。我们与神经病理学部分NIMH建立了合作，并收集了100多个人类三叉神经节和宫颈脊髓样本。这些组织用于人类伤害性电路的转录组和蛋白质分析。 我们正在与Rush University建立合作，以获取具有定义疼痛障碍患者的后DRG和脊髓；因此，可以研究基线和疼痛状态依赖性变化。 通过这项研究，我们希望对组织损伤，炎症和疼痛感之间的关系有基本的了解。在更广泛的框架中，这些研究探讨了突触可塑性的基本分子基础。当发生与疼痛相关的新水平的突触或药理输入时，我们假设神经元反应中的模块化，以及与癫痫或药物滥用等神经系统疾病相关的，将“通用”变化与电路特异性基因相结合以满足新刺激或活性的需求。了解分子曲目及其动态相互作用将使人们对触发和维持慢性疼痛和神经系统其他疾病的机制有更深入的了解。 在行为研究方面，我们已经开始剖析使用红外二极管激光刺激剂迅速进行A-DELTA神经元的作用。 这些研究表明，A-delta神经元在炎症性疼痛中被敏感，类似于C纤维，并导致假设是它们是介体或触发因素或触发因骨关节炎或癌症的突破性疼痛。 我们还确定A-DELTA纤维对RTX轴切开术最敏感，这可能是因为病变发生在Ranvier的多个节点上，因此细胞无法轻松修复。我们将更详细地研究此问题。因为刺激是如此短，因此在刺激后的前几毫秒内，在补偿性疼痛控制过程可以干预之前，可以详细研究感觉运动整合。这些类型的快速瞬态刺激通常是触发突破性疼痛发作的刺激。 早期翻译研究：一组最终的研究涉及鉴定小型化学物质，这些化学物质充当pH或香草素激动剂的TRPV1激活的阳性变构调节剂（PAMS）。我们的人类癌症研究表明，TRPV1是疼痛刺激的最重要的传感器之一，并且了解如何阻止，激活或敏感离子通道对于理解疼痛至关重要。 我们通过筛选小分子库在TRPV1上确定了新的动作。我们发现了在激动剂结合到定点位点或通过H+离子升高的激动剂结合时TRPV1激活的化合物。这些研究表明，TRPV1离子通道开放状态的变构调节可以访问以进行疼痛传播，以及存在用于疼痛调节和控制疼痛的新药理剂。在过去的一年中，我们筛选了300,000种化合物分子探针库，并确定了100多种直接激动剂和900多个PAM。 显然，并非所有这些单点的确定都是正确的，我们正在重新验证验证。 特异性的次级筛选将使用其他TRP和配体激活的离子通道，以及电生理记录和CA-45摄取。 我们希望获得用于TRPV1功能研究的新探针，以及可用于控制疼痛的PAM的新铅。这些研究已经发展到我们正在合成铅PAM进行评估的类似物的地步。