Naegleria fowleri induces MUC5AC and pro-inflammatory cytokines in human epithelial cells via ROS production and EGFR activation.
Naegleria fowleri is an amoeboflagellate responsible for the fatal central nervous system (CNS) disease primary amoebic meningoencephalitis (PAM). This amoeba gains access to the CNS by invading the olfactory mucosa and crossing the cribriform plate. Studies using a mouse model of infection have shown that the host secretes mucus during the very early stages of infection, and this event is followed by an infiltration of neutrophils into the nasal cavity. In this study, we investigated the role of N. fowleri trophozoites in inducing the expression and secretion of airway mucin and pro-inflammatory mediators. Using the human mucoepidermal cell line NCI-H292, we demonstrated that N. fowleri induced the expression of the MUC5AC gene and protein and the pro-inflammatory mediators interleukin-8 (IL-8) and interleukin-1 beta (IL-1 beta), but not tumour necrosis factor-alpha or chemokine c-c motif ligand 11 (eotaxin). Since the production of reactive oxygen species (ROS) is a common phenomenon involved in the signalling pathways of these molecules, we analysed if trophozoites were capable of causing ROS production in NCI-H292 cells by detecting oxidation of the fluorescent probe 2,7-dichlorofluorescein diacetate. NCI-H292 cells generated ROS after 15-30 min of trophozoite stimulation. Furthermore, the expression of MUC5AC, IL-8 and IL-1 beta was inhibited in the presence of the ROS scavenger DMSO. In addition, the use of an epidermal growth factor receptor inhibitor decreased the expression of MUC5AC and IL-8, but not IL-1 beta. We conclude that N. fowleri induces the expression of some host innate defence mechanisms, such as mucin secretion (MUC5AC) and local inflammation (IL-8 and IL-1 beta) in respiratory epithelial cells via ROS production and suggest that these innate immune mechanisms probably prevent most PAM infections.
Cervantes-Sandoval
Isaac
I
Department of Immunology, National School of Biological Sciences, National Polytechnic Institute, Av. Manuel M. Carpio and Plan de Ayala, Mexico City 11340, Mexico.|Department of Infectomic and Molecular Pathogenesis, Center for Research and Advanced Studies, National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico.
Serrano-Luna
José de Jesús
JJ
Department of Cell Biology, Center for Research and Advanced Studies, National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico.
Meza-Cervantez
Patricia
P
Department of Infectomic and Molecular Pathogenesis, Center for Research and Advanced Studies, National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico.
Arroyo
Rossana
R
Department of Infectomic and Molecular Pathogenesis, Center for Research and Advanced Studies, National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico.
Tsutsumi
Víctor
V
Department of Infectomic and Molecular Pathogenesis, Center for Research and Advanced Studies, National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico.
Shibayama
Mineko
M
Department of Infectomic and Molecular Pathogenesis, Center for Research and Advanced Studies, National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico.
D000818:Animals; D002460:Cell Line; D020808:Central Nervous System Protozoal Infections / Q000276:immunology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D007113:Immunity, Innate; D053583:Interleukin-1beta / Q000276:immunology*; D016209:Interleukin-8 / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D055271:Mucin 5AC / Q000276:immunology*; D016848:Naegleria fowleri / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology; D011799:Quinazolines; D017382:Reactive Oxygen Species / Q000378:metabolism*; D053058:Trophozoites / Q000276:immunology; D020032:Tyrphostins / Q000494:pharmacology
D053583:Interleukin-1beta; D016209:Interleukin-8; D055271:Mucin 5AC; D011799:Quinazolines; D017382:Reactive Oxygen Species; D020032:Tyrphostins; C101044:RTKI cpd; D066246:ErbB Receptors; D004121:Dimethyl Sulfoxide