Immune activation of the endogenous control of persistent pain

 描述(申请人提供)：数以百万计的人患有慢性疼痛，这是一个主要的健康问题。慢性口腔面部疼痛在美国非常普遍。最常见的持续性口腔面部疼痛疾病是颞下颌关节紊乱病(TMJD)，影响肌肉骨骼和关节组织，其来源是不同的。目前对慢性疼痛的治疗方法并不令人满意，迫切需要寻找和开发替代的有效的慢性疼痛疗法。近年来，骨髓基质细胞(BMSC)作为一种基于细胞的治疗方法引起了人们的极大兴趣。有趣的是，骨髓间充质干细胞似乎具有治疗慢性疼痛的潜力。在组织或神经损伤伴长时间痛过敏的大鼠模型中，静脉注射大鼠骨髓间充质干细胞可引起口面部痛觉过敏/超敏(抗痛觉过敏)的长期减弱，这种作用可被阿片受体拮抗剂减弱，提示内源性阿片类药物参与了这一作用。然而，骨髓间充质干细胞对持续性疼痛的作用机制仍不清楚。有证据表明，大多数静脉输注的骨髓间充质干细胞被困在肺部，而输注的细胞只在系统中停留几天到几周。研究表明，注入的骨髓间充质干细胞通过分泌与人体免疫系统相互作用的化学介质来产生治疗效果。我们推测，骨髓间充质干细胞通过其免疫相互作用和随后激活的内源性阿片系统产生止痛或抗伤害作用。我们将通过细胞培养、逆转录-定量实时聚合酶链式反应、免疫组织化学、Western印迹、酶联免疫吸附试验、荧光激活细胞分选、RNA干扰(RNAi)、转基因小鼠和行为药理学三个特定目标的组合方法来验证这一假说。我们将继续使用咬肌肌腱损伤的啮齿动物模型，它模仿肌源性的延长口面部伤害性感受。我们将重点使用雌性动物，因为女性比男性表现出更高的TMJ障碍患病率。目的1研究骨髓间充质干细胞对雌性动物疼痛和神经元活动的影响，并验证骨髓间充质干细胞参与脑内阿片类物质和调节N-甲基-D-天冬氨酸受体的假说。目的2将验证免疫细胞的单核/巨噬细胞群参与介导骨髓间充质干细胞产生的疼痛缓解的假设。目的3将验证这一假设，即单核细胞衍生的趋化因子在骨髓间充质干细胞产生的阿片受体上调和缓解持续性疼痛中起关键作用。这些发现将为骨髓间充质干细胞诱导的疼痛缓解提供新的细胞机制，并有助于开发一种有效地利用内源性疼痛调制治疗慢性疼痛的方法，并有助于将其转化为临床环境。

 DESCRIPTION (provided by applicant): Millions of people suffer from chronic pain, which is a major health problem. Chronic orofacial pain is highly prevalent in the US. The most common persistent orofacial pain condition, temporomandibular joint disorders (TMJD), affects the musculoskeletal and joint tissues and is heterogeneous in origin. The current treatment for chronic pain conditions is unsatisfactory and there is an urgent need for searching and developing alternative and effective chronic pain therapy. Recently, bone marrow stromal cells (BMSC) have generated considerable interest as a candidate for cell-based therapy. Interestingly, BMSC appear to have potential to treat chronic pain conditions. In rat models of tissue or nerve injury with long-lasting pain hypersensitivity, intravenous infusion of rat BMSC produced long-term attenuation of orofacial hyperalgesia/allodynia (antihyperalgesia) and this effect was attenuated by the opioid receptor antagonist, suggesting the involvement of endogenous opioids. However, the mechanisms of the effect of BMSC on persistent pain remain elusive. Evidence indicates that the majority of the intravenously infused BMSC are trapped in the lungs and that the infused cells only stay in the system for a matter of days to a few weeks. Studies suggest that the infused BMSC produce their therapeutic effects through secretion of chemical mediators that interact with the body's immune system. We hypothesize that BMSC produce pain-relieving, or antinociceptive effect through their immune interactions and subsequent activation of the endogenous opioid system. We will test this hypothesis by a combination of approaches involving cell cultures, Reverse Transcription-quantitative real time Polymerase Chain Reaction, immunohistochemistry, Western blot, Enzyme-linked immunosorbent assay, fluorescence activated cell sorting, RNA interference (RNAi), transgenic mice and behavioral pharmacology in three Specific Aims. We will continue to use a rodent model of the masseter muscle tendon injury, which mimics prolonged orofacial nociception of myogenic origin. We will focus on using female animals since women exhibit a higher prevalence of TMJ disorders than men. Aim 1 will examine the effect of BMSC on pain and neuronal activity in female animals and test the hypothesis that BMSC engage brain endogenous opioids and regulate N-methyl-D-aspartate receptors. Aim 2 will test the hypothesis that the monocyte/macrophage population of immune cells are involved in mediating the BMSC-produced pain relief. Aim 3 will test the hypothesis that monocyte-derived chemokines are critical in the BMSC-produced upregulation of opioid receptors and attenuation of persistent pain. Findings will provide novel cellular mechanisms for BMSC-induced pain relief and help to develop an approach to effectively engage the endogenous pain modulation for the treatment of chronic pain and facilitate translating it into clinical settings.