Diminished COX-2/PGE2-Mediated Antiviral Response Due to Impaired NOX/MAPK Signaling in G6PD-Knockdown Lung Epithelial Cells.
Glucose-6-phosphate dehydrogenase (G6PD) provides the reducing agent NADPH to meet the cellular needs for reductive biosynthesis and the maintenance of redox homeostasis. G6PD-deficient cells experience a high level of oxidative stress and an increased susceptibility to viral infections. Cyclooxygenase-2 (COX-2) is a key mediator in the regulation of viral replication and inflammatory response. In the current study, the role of G6PD on the inflammatory response was determined in both scramble control and G6PD-knockdown (G6PD-kd) A549 cells upon tumor necrosis factor-α (TNF-α) stimulation. A decreased expression pattern of induced COX-2 and reduced production of downstream PGE2 occurred upon TNF-α stimulation in G6PD-kd A549 cells compared with scramble control A549 cells. TNF-α-induced antiviral activity revealed that decreased COX-2 expression enhanced the susceptibility to coronavirus 229E infection in G6PD-kd A549 cells and was a result of the decreased phosphorylation levels of MAPK (p38 and ERK1/2) and NF-κB. The impaired inflammatory response in G6PD-kd A549 cells was found to be mediated through NADPH oxidase (NOX) signaling as elucidated by cell pretreatment with a NOX2-siRNA or NOX inhibitor, diphenyleneiodonium chloride (DPI). In addition, NOX activity with TNF-α treatment in G6PD-kd A549 cells was not up-regulated and was coupled with a decrease in NOX subunit expression at the transcriptional level, implying that TNF-α-mediated NOX signaling requires the participation of G6PD. Together, these data suggest that G6PD deficiency affects the cellular inflammatory response and the decreased TNF-α-mediated antiviral response in G6PD-kd A549 cells is a result of dysregulated NOX/MAPK/NF-κB/COX-2 signaling.
Molecular Medicine Research Center, Chang Gung University, Taoyuan City, Taiwan.
Hsin-Ru
HR
Lin
Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan City, Taiwan.
Yi-Hsuan
YH
Wu
Graduate Institute of Biomedical Science, College of Medicine, Chang Gung University, Taoyuan City, Taiwan.
Wei-Chen
WC
Yen
Healthy Aging Research Center, Chang Gung University, Taoyuan City, Taiwan.|Department of physiology and pharmacology, College of Medicine, Chang Gung University, Taoyuan City, Taiwan.
Chuen-Mao
CM
Yang
Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan City, Taiwan.|Healthy Aging Research Center, Chang Gung University, Taoyuan City, Taiwan.|Department of Pediatric Hematology, Chang Gung Memorial Hospital, Lin-Kou, Taiwan.
Daniel Tsun-Yee
DT
Chiu
D045744:Cell Line, Tumor; D017934:Coronavirus / Q000502:physiology*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000821:virology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008168:Lung / Q000166:cytology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019255:NADPH Oxidases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014779:Virus Replication / Q000187:drug effects
D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D005954:Glucosephosphate Dehydrogenase; D051546:Cyclooxygenase 2; D019255:NADPH Oxidases; D048031:JNK Mitogen-Activated Protein Kinases; D015232:Dinoprostone