Department of Neurosurgery, School of Medicine, Jinling Hospital, Southern Medical University (Guangzhou), 305 East Zhongshan Road, Nanjing, 210002, Jiangsu Province, People's Republic of China.
Neurochem Res. 2013 Oct;38(10):2072-83. doi: 10.1007/s11064-013-1115-z. Epub 2013 Jul 28.
Inflammatory response plays an important role in the pathogenesis of secondary damage after traumatic brain injury (TBI). The inflammasome is a multiprotein complex involved in innate immunity and a number of studies have suggested that the inflammasome plays a critical role in a host inflammatory signaling. Nucleotide-binding domain, leucine-rich repeat, pyrin domain containing 3 (NLRP3) is a key component of the NLRP3-inflammasome, which also includes apoptotic speck-containing protein (ASC) with a cysteine protease (caspase)-activating recruitment domain and pro-caspase1. Activation of the NLRP3-inflammasome causes the processing and release of the interleukin 1 beta (IL-1β) and interleukin 18 (IL-18). Based on this, we hypothesized that the NLRP3-inflammasome could participate in the inflammatory response following TBI. However, the expression of NLRP3-inflammasome in cerebral cortex after TBI is not well known. Rats were randomly divided into control, sham and TBI groups (including 6 h, 1 day, 3 day and 7 day sub-group). TBI model was induced, and animals were sacrificed at each time point respectively. The expression of NLRP3-inflammasome was measured by quantitative real-time polymerase chain reaction, western blot and immunohistochemistry respectively. Immunofluorescent double labeling was performed to identify the cell types of NLRP3-inflammasome's expression. Moreover, enzyme linked immunosorbent assay was used to detect the alterations of IL-1β and IL-18 at each time point post-injury. The results showed that, TBI could induce assembly of NLRP3-inflammasome complex, increased expression of ASC, activation of caspase1, and processing of IL-1β and IL-18. These results suggested that NLRP3-inflammasome might play an important role in the inflammation induced by TBI and could be a target for TBI therapy.
炎症反应在创伤性脑损伤 (TBI) 后继发性损伤的发病机制中起着重要作用。炎症小体是参与固有免疫的多蛋白复合物,许多研究表明炎症小体在宿主炎症信号中起着关键作用。核苷酸结合域富含亮氨酸重复序列,pyrin 域包含 3 (NLRP3) 是 NLRP3-炎症小体的关键组成部分,还包括含有半胱氨酸蛋白酶 (caspase)-激活募集结构域和前半胱天冬酶 1 的凋亡斑点蛋白 (ASC)。NLRP3-炎症小体的激活导致白细胞介素 1β (IL-1β) 和白细胞介素 18 (IL-18) 的加工和释放。基于此,我们假设 NLRP3-炎症小体可能参与 TBI 后的炎症反应。然而,TBI 后大脑皮层中 NLRP3-炎症小体的表达尚不清楚。大鼠随机分为对照组、假手术组和 TBI 组(包括 6 h、1 天、3 天和 7 天亚组)。分别在每个时间点诱导 TBI 模型,并进行动物处死。通过实时定量聚合酶链反应、Western blot 和免疫组织化学分别测量 NLRP3-炎症小体的表达。通过免疫荧光双标记法鉴定 NLRP3-炎症小体表达的细胞类型。此外,酶联免疫吸附试验用于检测损伤后各时间点 IL-1β 和 IL-18 的变化。结果表明,TBI 可诱导 NLRP3-炎症小体复合物的组装,增加 ASC 的表达,caspase1 的激活,以及 IL-1β 和 IL-18 的加工。这些结果表明,NLRP3-炎症小体可能在 TBI 引起的炎症中发挥重要作用,并且可能成为 TBI 治疗的靶点。