title: Interleukin-17A Induces IL-1β Secretion From RPE Cells Via the NLRP3 Inflammasome.
abstract: OBJECTIVE
  Inflammasome activation and IL-1β production have been proposed to have an important role in age-related macular degeneration (AMD). Growing evidence is emerging for involvement of interleukin-17A (IL-17A) in AMD pathogenesis. We investigated the effects of IL-17A on the activation of inflammasome and production of IL-1β in primary human RPE cells.
  
  
  METHODS
  Primary human RPE cells were isolated and cultured for the following experiments. Expression patterns of IL-17 receptor A (IL-17RA), IL-17 receptor C (IL-17RC), and ACT1 were analyzed by RT-PCR, flow cytometry, and immunofluorescence. IL-17A was added to the cell cultures, and cytokine expression, signaling pathways, and inflammasome machinery were investigated using real-time RT-PCR, ELISA, Western blot, flow cytometry, and small interfering RNA.
  
  
  RESULTS
  Retinal pigment epithelial cells constitutively expressed IL-17RA, IL-17RC, and ACT1. IL-17A upregulated the mRNA levels of pro-IL-1β, IL-8, CCL2, and CCL20, as well as the protein level of IL-1β. IL-17A induced the phosphorylation of Akt, Erk1/2, p38 MAPK, and NF-κB p65 in RPE cells. Blocking NF-κB attenuated IL-17A-induced expression of pro-IL-1β mRNA. IL-17A enhanced pro-caspase-1 and NLRP3 mRNA expression. Inhibiting caspase-1 activity and silencing NLRP3 decreased IL-1β secretion, confirming NLRP3 as the IL-17A-responsive inflammasome on the posttranscriptional level. The mechanism of IL-17A-triggered NLRP3 activation and subsequent IL-1β secretion was found to involve the generation of reactive oxygen species.
  
  
  CONCLUSIONS
  Our results suggest that IL-17A triggers a key inflammatory mediator, IL-1β, from RPE cells, via NLRP3 inflammasome activation, holding therapeutic potential for AMD.
authors.affiliation: Research Center Eye & ENT Hospital of Fudan University, Shanghai, China 2Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
authors.forename: Shujie
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, Shanghai Skin Disease Hospital, Shanghai, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Yu
authors.affiliation: Research Center Eye & ENT Hospital of Fudan University, Shanghai, China 2Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Research Center Eye & ENT Hospital of Fudan University, Shanghai, China 2Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
authors.forename: Shenghai
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Research Center Eye & ENT Hospital of Fudan University, Shanghai, China 2Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.
authors.forename: Jihong
authors.initials: J
authors.lastname: Wu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D058847:Inflammasomes / Q000378:metabolism*; D020381:Interleukin-17 / Q000494:pharmacology*; D053583:Interleukin-1beta / Q000378:metabolism*; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D018123:Receptors, Interleukin / Q000235:genetics; D053722:Receptors, Interleukin-17 / Q000235:genetics; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C508717:IL17A protein, human; C109985:IL17RA protein, human; C448419:IL17RC protein, human; D058847:Inflammasomes; D020381:Interleukin-17; D053583:Interleukin-1beta; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D018123:Receptors, Interleukin; D053722:Receptors, Interleukin-17; C414202:TRAF3IP2 protein, human; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins