BACKGROUND & AIMS:
INTRODUCTION:Exposure to airborne particulate matter (PM) increases the proportion of oral inflammatory diseases. During the formation of inflammatory conditions, the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome activation plays an important regulator. Carbon monoxide (CO) arising from heme degradation, catalyzed particularly by heme oxygenase-1 (HO-1), has been shown to own cytoprotective effects including anti-inflammation and antioxidant. Here, we determined the novel mechanisms of carbon monoxide releasing molecule-2 (CORM-2) on PM-induced inflammatory responses in human oral keratinocytes (HOKs).
METHODS:The effects of CORM-2 on the expression of various inflammatory proteins induced by PM were determined by Western blot, real-time PCR, promoter assay, and ELISA. The involvement of signaling molecules in these responses was studied by using the selective pharmacological inhibitors and siRNAs.
RESULTS:We proved that PM enhanced C-reactive protein (CRP) levels, NLRP3 inflammasome and caspase-1 activation, and IL-1β release, which were reduced by preincubation with CORM-2. Transfection with PKCα siRNA and preincubation with the ROS scavenger (N-acetyl-cysteine, NAC), an inhibitor of NADPH oxidase (diphenyleneiodonium, DPI), or the mitochondria-specific superoxide scavenger (MitoTEMPO) inhibited PM-mediated inflammatory responses. In addition, PM-regulated PKCα and NADPH oxidase activation as well as NADPH oxidase- and mitochondria-derived ROS generation were inhibited by CORM-2, but not inactivate CORM-2 (iCORM-2) pretreatment. At the end, we confirmed that CORM-2 improved PM-induced inflammatory responses via the induction of Nrf2 activation and HO-1 expression.
CONCLUSION:We suggest that CORM-2 inhibits PM-induced inflammatory responses in HOKs via the inhibition of PKCα/ROS/NLRP3 inflammasome activation combined with the induction of Nrf2/HO-1 expression.
背景与目标:
简介:接触空气中的颗粒物(PM)会增加口腔炎性疾病的比例。在炎性疾病形成过程中,核苷酸结合结构域和富含亮氨酸的重复蛋白3(NLRP3)炎性小体激活起着重要的调节作用。由血红素降解产生的一氧化碳(CO)特别是被血红素加氧酶-1(HO-1)催化,已显示出具有细胞保护作用,包括抗炎和抗氧化剂。在这里,我们确定了一氧化碳释放分子2(CORM-2)对PM诱导的人类口腔角质形成细胞(HOKs)炎症反应的新机制。
方法:采用Western blot,实时荧光定量PCR,启动子检测和ELISA法检测CORM-2对PM诱导的多种炎症蛋白表达的影响。通过使用选择性药理抑制剂和siRNA,研究了信号分子参与这些应答的过程。
结果:我们证明了PM可以提高C反应蛋白(CRP)水平,NLRP3炎性小体和caspase-1的活化以及IL-1β的释放,与CORM-2一起预孵育可以降低PM。用PKCαsiRNA转染并与ROS清道夫(N-乙酰基-半胱氨酸,NAC),NADPH氧化酶抑制剂(二苯撑碘鎓,DPI)或线粒体特有的超氧化物清道夫(MitoTEMPO)预孵育可抑制PM介导的炎症反应。此外,CORM-2抑制了PM调节的PKCα和NADPH氧化酶的活化以及NADPH氧化酶和线粒体的ROS生成,但未灭活CORM-2(iCORM-2)预处理。最后,我们证实了CORM-2通过诱导Nrf2激活和HO-1表达改善了PM诱导的炎症反应。
结论:我们建议CORM-2通过抑制PKCα/ ROS / NLRP3炎性体激活并诱导Nrf2 / HO-1表达来抑制PM诱导的HOKs炎症反应。