Gαq在急性非感染性炎症中的作用与机制

Gout is an autoinflammatory disorder associated with deposition of monosodium urate (MSU) crystals in joints and periarticular tissues. Studies indicated that the responses of human neutrophils and monocytes to MSU crystals represent an integral part of this innate response and a key component of the acute in?ammatory response associated with gout. The proinflammatory factor Interleukin-1beta (IL-1β) is a key pathogenic factor in Gout development. Gαq, the alpha submit of Gq protein, encoded by GNAQ, is ubiquitously expressed in mammalians. Gq transduces many external signals into the cell, and controls many biological functions. Recent studies demonstrated the function and important roles of Gαq in the immune regulation and autoimmunity. Our previous data indicated that Gαq deficient neutrophils and dendritic cells (DCs) are defect in migration towards several chemokines. Therefore, Gαq may involve in the pathogenesis of Gout by regulating PMN and DC migration and function. To prove this hypothesis, we tested the expression of Gαq and IL-1β in PBMC from Gout patients, we have found that the expression of Gαq mRNA in the Peripheral blood mononuclear cells (PBMCs) from gout patients was significantly increased compared with that in healthy controls and the Gαq abnormal expression levels were significantly positive correlated with IL-1β. We also found that the expression of IL-1β and tumor necrosis factor alpha (TNF-α) were decreased in splenocytes of Gαq deficient mouse. Taking together, we hypothesized that Gαq is involved in the pathogenesis of gout by regulate neutrophils and monocytes chemotaxis and the expression of IL-1β. In this study, we will dissect the molecular mechnism of the neutrophils and monocytes chemotaxis in gout. Meanwhile, we will also explore the possibility of Gαq in regulating the expression of IL-1β. We intend to further reveal the mechnisms of Gαq in pathogenesis of gout and provide new clues to treat gout.

急性痛风是由尿酸钠单晶体（MSU）在关节腔内激活单核巨噬细胞和中性粒细胞并产生大量炎症因子，尤其是IL-1β，并造成单核巨噬细胞和中性粒细胞在炎症关节局部大量聚集而引起的急性炎症。故，单核巨噬细胞和中性粒细胞是急性痛风发生的关键炎症细胞。Gαq是由Gnaq基因编码的Gq蛋白的α功能亚单位，广泛表达于各种组织器官中。我们前期研究发现Gαq调控非特异性免疫细胞树突状细胞和中性粒细胞的迁移。预实验中发现痛风患者外周血PBMC中Gαq表达增高且Gαq的表达与IL-1β的表达呈正相关；Gαq基因敲除小鼠脾细胞IL-1β和TNF-α表达显著降低。我们推测，Gαq通过调控单核巨噬细胞和中性粒细胞的迁移和炎症因子的表达参与了痛风的发病。本研究将应用Gnaq-/-小鼠，结合痛风患者外周血，从疾病、细胞、动物三方面详细研究Gαq参与痛风发病的机制，并进一步探讨其作为痛风新治疗靶点的可能性。

Gαq是由Gnaq编码的Gq蛋白的功能单位,广泛表达于各器官组织中。申请人既往研究发现，Gαq参与多种免疫细胞的分化功能。炎症是多种自身免疫性疾病的共有过程。本课题主要研究Gαq在非感染性炎症中的作用与机制。本研究成果共发表SCI论文6篇，另外已接受1篇文章，取得的主要成果包括：1.在痛风的患者中检测Gαq的表达并分析与炎症指标的相关性，证明Gαq在痛风炎症中的负调控作用，通过Gnaq-/-骨髓嵌合小鼠制备MSU诱导的炎症模型，证明Gαq负调控MSU诱导的炎症反应，特别是IL-1β的合成分泌。并通过体外细胞实验验证Gαq主要通过负调控ROS-NLRP3通路从而影响IL-1β的分泌而调控炎症过程。该部分实验结果证实了Gαq在痛风中的调控作用及其可能的机制。2.在银屑病患者及Gnaq-/-骨髓嵌合小鼠验证Gαq负调控IL-17，TNF-α等细胞因子参与银屑病发病，为银屑病的免疫学调控异常提供了一种新的机制探讨。3.通过分析临床关节炎患者的血清学指标，发现关节炎患者，特别是痛风患者的PCT水平明显升高，提示了PCT不仅仅作为感染的临床指标，同时可作为预测炎症性关节炎，特别是痛风性关节炎的观察指标。4.通过分析痛风患者外周血白细胞的miRNA芯片结果，并通过体外细胞学实验验证miR-488和miR-920对MSU诱导的炎症反应的负调控作用，该结果提示miR-488和miR-920可作为痛风治疗或研究的新靶点。5.本课题同时还研究了IL-33在痛风中的作用，分析其表达与血清学指标相关性，结果提示IL-33在痛风中可能通过调控脂质代谢发挥对肾脏的保护作用。通过以上实验结果，我们对Gαq在炎症性疾病中的作用及其机制进行了深入的探讨，并在临床水平，体内外实验水平发现了痛风研究新的观察指标，新的靶点。为炎症的免疫学调控过程提供了一些新的理论基础及靶点的选择。