Division of Nephrology, Department of Internal Medicine, Ewha Medical Research Center, Ewha Womans University School of Medicine, Seoul, South Korea.
Department of Internal Medicine, Seonam Hospital, Seoul, Korea.
FASEB J. 2019 Feb;33(2):3035-3050. doi: 10.1096/fj.201800292RR. Epub 2018 Oct 24.
Phenotype transition of mesothelial cells, such as epithelial-to-mesenchymal transition (EMT), is one of the early mechanisms of peritoneal fibrosis, which is mediated by oxidative stress and inflammation. Nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a multiprotein oligomer that promotes the maturation of IL-1β and IL-18. Paricalcitol is reported to exert an anti-inflammatory effect; however, there are no studies as to whether paricalcitol modulates the activation of NLRP3 inflammasome. We investigated the role of NLRP3 inflammasome in peritoneal EMT with an exploration of the effect of paricalcitol on oxidative stress, NLRP3 inflammasome, and EMT of mesothelial cells. TGF-β1-induced EMT in human peritoneal mesothelial cells (HPMCs) was associated with an up-regulation of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and procaspase-1, with an increased production of IL-1β and IL-18, which was ameliorated by small interfering (si)NLRP3, siASC, caspase inhibitors, or neutralizing antibodies for IL-1β and IL-18. TGF-β1 enhanced reactive oxygen species generation with an increase in NADPH oxidase (NOX) activity and mitochondrial NOX4 production. Paricalcitol alleviated TGF-β1-induced EMT and the NLRP3 inflammasome, which was associated with a down-regulation of NOX activity by interfering with p47phox and p22phox interaction and mitochondrial NOX4 production in HPMCs. Taken together, paricalcitol ameliorated EMT of HPMCs via modulating an NOX-dependent increase in the activity of NLRP3 inflammasome. Paricalcitol could be a novel approach to protect the peritoneum from the development of EMT and peritoneal fibrosis.-Ko, J., Kang, H.-J., Kim, D.-A., Ryu, E.-S., Yu, M., Lee, H., Lee, H. K., Ryu, H.-M., Park, S.-H., Kim, Y.-L., Kang, D.-H. Paricalcitol attenuates TGF-β1-induced phenotype transition of human peritoneal mesothelial cells (HPMCs) via modulation of oxidative stress and NLRP3 inflammasome.
间皮细胞的表型转化，如上皮-间充质转化（EMT），是腹膜纤维化的早期机制之一，其由氧化应激和炎症介导。核苷酸结合寡聚化结构域样受体家族富含吡喃结构域蛋白 3（NLRP3）炎性小体是一种多蛋白寡聚体，可促进白细胞介素-1β（IL-1β）和白细胞介素-18（IL-18）的成熟。已有研究报道帕立骨化醇具有抗炎作用，但目前尚无研究表明帕立骨化醇是否能调节 NLRP3 炎性小体的激活。我们研究了 NLRP3 炎性小体在腹膜 EMT 中的作用，并探讨了帕立骨化醇对氧化应激、NLRP3 炎性小体和间皮细胞 EMT 的影响。TGF-β1 诱导人腹膜间皮细胞（HPMCs）发生 EMT 时，NLRP3、凋亡相关斑点样蛋白（ASC）和前半胱天冬酶-1 的表达上调，IL-1β和 IL-18 的产生增加，而用 NLRP3、ASC 的 siRNA、半胱天冬酶抑制剂或中和抗 IL-1β 和 IL-18 的抗体可减轻这种情况。TGF-β1 增强活性氧（ROS）生成，增加 NADPH 氧化酶（NOX）活性和线粒体 NOX4 产生。帕立骨化醇减轻了 TGF-β1 诱导的 EMT 和 NLRP3 炎性小体，这与帕立骨化醇通过干扰 HPMCs 中 p47phox 和 p22phox 相互作用和线粒体 NOX4 产生来下调 NOX 活性有关。总之，帕立骨化醇通过调节 NOX 依赖性 NLRP3 炎性小体活性来改善 HPMCs 的 EMT。帕立骨化醇可能是一种保护腹膜免受 EMT 和腹膜纤维化发展的新方法。
