Mechanisms of Pain and Immune Processes

概述：这个转化研究项目解决了伤害感受传递的分子和病理生理过程，以及研究慢性疼痛、自身免疫性疾病、传染病及其在人类患者中的交叉的新方法。慢性神经性疼痛可影响身体的任何部位，可由各种损伤、感染、自身免疫或代谢紊乱（如糖尿病周围神经病变）引起。我们正在测试这样一种假设，即在一些患者中，慢性疼痛是由与周围神经或雪旺细胞中产生的针对蛋白质的自身抗体相关的免疫病理过程维持的。自身抗体是某些大纤维周围神经病变（如副肿瘤疾病）的罪魁祸首。如果疼痛是一个组成部分，我们假设存在针对小直径痛觉（伤害性）C-或a - δ神经纤维产生的神经末梢蛋白质的自身抗体。为了验证疼痛的神经性疾病与自身免疫性成分有关的假设，我们建立了一种灵敏、定量的液相发光试验，使用重组蛋白抗原-荧光素酶融合蛋白作为示踪剂，在哺乳动物细胞中表达。这种检测方法被称为荧光素酶免疫沉淀系统（LIPS），我们已经发表了多篇论文，表明LIPS可以稳定而敏感地测量血清、血浆、脑脊液或唾液中的抗体。本研究的目标是了解(a)人类慢性疼痛疾病的分子和细胞生物学机制，以及(b)利用这些知识设计新的疼痛疾病治疗和诊断方法。

Overview: This translational research program addresses molecular and pathophysiological processes of nociceptive transmission and new ways to investigate chronic pain, autoimmune conditions, infectious diseases and their intersection in human patients. Chronic neuropathic pain can affect any part of the body and can occur due to a variety of insults, infections, and autoimmune or metabolic disorders (e.g., diabetic peripheral neuropathy). We are testing the hypothesis that, in some patients, chronic pain is maintained by immunopathological processes related to autoantibodies generated against proteins in peripheral nerve or Schwann cells. Autoantibodies are known culprits in certain large fiber peripheral neuropathies such as in paraneoplastic disorders. Where pain is a component, we hypothesize the presence of autoantibodies to proteins found in nerve endings arising from small diameter pain-sensing (nociceptive) C- or A-delta nerve fibers. To test the hypothesis that painful neuropathic conditions have an autoimmune component we established a sensitive, quantitative, liquid phase luminescence assay that uses recombinant protein antigen-luciferase fusion proteins as tracers, which are expressed in mammalian cells. This assay is called luciferase immunoprecipitation systems (LIPS) and we have multiple published papers showing that LIPS can robustly and sensitively measure antibodies in serum, plasma, cerebrospinal fluid or saliva. The goals of this research are to understand (a) the molecular and cell biological mechanisms underlying human chronic pain disorders, and (b) to use this knowledge to devise new treatments and diagnostics for pain disorders. In this project an autoimmune hypothesis is explored. The assay methodology we established has great versatility due to its sensitivity, modularity, and use of recombinant DNA methodology to generate protein antigen tracers. As a result earlier investigations evaluated a range of diseases and disorders that antibodies play a role in including infectious diseases, with and without nervous system involvement, various autoimmune disorders, which may have nervous system symptomology in subsets of patients and other types of screening and methodological variants. In one study, we identified antibodies to interferon gamma in serum from several neuropathic pain patients and then generated a larger panel of anti-cytokine antibody probes, however, antibodies to these other cytokines were not widely represented in the neuropathy patients. Extending testing of the panel to another patient population revealed that anti-interferon gamma antibodies play a role opportunistic infections and this collaborative research work defined a new mechanism of disease in certain patient populations. In many neural autoimmune disorders the major autoantigens are frequently plasma membrane receptors or ion channels. We have generated several such probes for neuropathic pain disorders, notably the beta-adrenergic receptor and a potassium channel based on published reports, and are currently testing to determine if the LIPS assay can detect antibodies to this protein in appropriate individuals. We are currently working a PNS infectious disease disorder, shingles or herpes zoster, that can evolve into a painful neurological manifestation called post-herpetic neuralgia (PHN). We detected some patients with neutralizing anti-cytokine autoantibodies and, interestingly, all of these had PHN. This suggests that some patients with PHN may require additional intervention to control the disorder other than just pain medications. One of the most compelling aspects of this project is the progressive layering and evolution of the datasets and their uses. As we increase the number of test antigens, and assay across conditions and diseases, we assemble comprehensive evaluations of immune and autoimmune responses. This is accomplished by determination of (a) the extent and specificity of immune response to orthologous proteins and protein fragments, (b) overlap in antigen profiles indicative of common denominators or general mechanisms, and (c) antigenicity within an entire signaling pathway involved in inter- or intracellular communication. An example is the antigenicity of the TRIM family of proteins in Sjogren's Syndrome. Another example is a new autoantigen-based classification of patients with Lupus Erythematosis that we demonstrated by multiple autoantigen profiling. An example of a new use for public health monitoring is our earlier demonstration of autoantibody measurements in saliva, which highlights the feasibility of establishing non-invasive, saliva-based assays for many types of human diseases. Saliva-based monitoring could be applied to determinations of vaccine immune status for large or vulnerable populations of people or the pediatric population. Eventually, full multiple antigen profiling can be implemented to obtain a deeper level of understanding of many complex human disease states.