Transcriptional firing helps to drive NETosis.
Neutrophils are short-lived innate immune cells. These cells respond quickly to stimuli, and die within minutes to hours; the relevance of DNA transcription in dying neutrophils remains an enigma for several decades. Here we show that the transcriptional activity reflects the degree of DNA decondensation occurring in both NADPH oxidase 2 (Nox)-dependent and Nox-independent neutrophil extracellular trap (NET) formation or NETosis. Transcriptomics analyses show that transcription starts at multiple loci in all chromosomes earlier in the rapid Nox-independent NETosis (induced by calcium ionophore A23187) than Nox-dependent NETosis (induced by PMA). NETosis-specific kinase cascades differentially activate transcription of different sets of genes. Inhibitors of transcription, but not translation, suppress both types of NETosis. In particular, promoter melting step is important to drive NETosis (induced by PMA, E. coli LPS, A23187, Streptomyces conglobatus ionomycin). Extensive citrullination of histones in multiple loci occurs only during calcium-mediated NETosis, suggesting that citrullination of histone contributes to the rapid DNA decondensation seen in Nox-independent NETosis. Furthermore, blocking transcription suppresses both types of NETosis, without affecting the reactive oxygen species production that is necessary for antimicrobial functions. Therefore, we assign a new function for transcription in neutrophils: Transcriptional firing, regulated by NETosis-specific kinases, helps to drive NETosis.
Innate Immunity Research Lab, Physiology and Experimental Medicine, PGCRL, The Hospital for Sick Children Research Institute, 686 Bay St, Toronto M5G 0A4, Canada.|Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada.
Meraj A
MA
Khan
Innate Immunity Research Lab, Physiology and Experimental Medicine, PGCRL, The Hospital for Sick Children Research Institute, 686 Bay St, Toronto M5G 0A4, Canada.|Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada.|Institute of Medical Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada.
Nades
N
Palaniyar
D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D065206:Extracellular Traps / Q000187:drug effects / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D053263:Gene Regulatory Networks; D056426:Genetic Loci; D015759:Ionomycin / Q000737:chemistry; D000074662:NADPH Oxidase 2 / Q000235:genetics / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism*; D016366:Open Reading Frames; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D002843:Chromatin; D003609:Dactinomycin; D015759:Ionomycin; D000074662:NADPH Oxidase 2