脊髓IL-33/ST2信号通路介导的神经免疫调节对RA大鼠外周炎症和痛觉过敏的调控及机制研究

Rheumatoid arthritis is a refractory disease and its mechanism is still not well understood. Reports have demonstrated that noxious stimuli from inflamed or injured tissues may increase the excitability of spinal dorsal horn neurons (a process known as central sensitization), which can signal back and contribute to peripheral inflammation. IL-33 is a newly recognized proinflammatory cytokines and ST2 is its receptor. A number of studies indicate that spinal IL-33/ST2 signaling pathway is involved in central sensitization. Our recent study also found that spinal IL-33 is activated in the presence of peripheral inflammation in rats with adjuvant-induced arthritis (AIA), and its downstream signaling pathways (NF-κB/p65) is involved in development of peripheral inflammation. Therefore, we assume that IL-33 are up-regulated in the spinal cord following peripheral inflammation and subsequent activating its downstream signaling pathways, and contributes to central sensitization. In turn, the spinal cord signal the periphery to modulate inflammation. Here we will culture nerve cells in vitro and establish a rat model of adjuvant-induced arthritis. Using western blot, ENSA, siRNA and patch clamp etc, we will detect the role and mechanism of IL-33/ST2 pathway in the pathogenesis of peripheral inflammation and hyperalgesia, which were both modulated by central nervous system.Thus we try to find a novel preventative and therapeutic approach for Rheumatoid arthritis.

类风湿性关节炎（RA）是一种复杂的难治性疾病，其发病机制尚未完全明确。研究证实关节组织损伤或炎症可导致中枢敏化，而敏化的中枢也可以通过神经免疫调控RA的发病。IL-33/ST2是新发现的一种促炎细胞因子和其受体，其在中枢敏化中起着重要作用。我们的前期工作也发现佐剂性关节炎（AIA）大鼠脊髓IL-33的表达明显上调，并证实其下游通路NF-κB/p65参与了中枢对AIA大鼠外周炎症的调控。据此，我们推测”脊髓IL-33在外周组织损伤或炎症后表达增加，进而激活其相应的下游通路，最终导致脊髓中枢敏化而返回信号调控外周炎症”。为验证这一假说，我们拟体外培养神经细胞和构建大鼠AIA模型，运用Western blot、EMSA、siRNA、膜片钳等技术，从分子、细胞以及动物整体水平探讨IL-33/ST2信号通路在中枢调控外周炎症和痛觉过敏中的作用及机制，项目的实施可望为RA的防治提供新的理论依据。

类风湿性关节炎（RA）是一种复杂的难治性疾病，迁延难愈，其发病机制尚未完全明确。本课题组体外培养神经细胞和构建大鼠AIA模型，运用Western blot、qPCR、siRNA、免疫荧光等技术，从分子、细胞以及动物整体水平探讨IL-33/ST2信号通路在外周炎症和痛觉过敏中的作用及机制。首先，我们构建了IL-33基因RNA干扰慢病毒载体（LV-shIL-33），转染体外培养的脊髓星形胶质细胞，证实LV-shIL-33可使星形胶质细胞的IL-33基因表达下调，并能抑制LPS导致的TNF-α、IL-1β和IL-6的上调效应。此外，我们建立了大鼠佐剂性关节炎模型（AIA），鞘内注射LV-shIL-33能下调AIA大鼠IL-33蛋白的表达，并且能降低大鼠的痛觉过敏、足跖肿胀以及关节破坏。同时能减少脊髓TNF-α, IL-1β和COX-2的过表达。另外，我们还构建大鼠非压迫性腰椎间盘突出症模型，髓核作用于背根神经节可使脊髓IL-33和ST2的表达增加，其主要分布于脊髓背角的神经元、星形胶质细胞和少突胶质细胞。鞘内给予LV-shIL-33能降低IL-33的表达，同时减轻大鼠的机械痛阈。同时，鞘内注射LV-shIL-33可降低脊髓IL-1β、TNF-α和COX-2的过度表达，并降低JNK、ERK和NF-κB/p65的表达。这些都表明脊髓IL-33/ST2信号通路在外周炎症和痛觉过敏的发生发展过程中起着重要作用，因此，抑制脊髓IL-33的表达对外周炎症性疾病可能是一种潜在的治疗方法。