Project description:Our study aims to analyze time-dependent changes in neutrophil phenotype, compare them with included neutrophil-specific mutants, and indentify common signatures among the 5 groups
Project description:Introduction: A maladaptive inflammatory response has been implicated in the pathogenesis of severe and critical COVID-19. This study aimed to characterize the temporal dynamics of this response and investigate whether critical disease is associated with distinct gene expression patterns. Methods: We performed microarray analysis of serial whole blood RNA samples from 19 patients with critical COVID-19, 15 patients with severe but non-critical disease and 11 healthy controls. We assessed whole blood gene expression patterns by differential gene expression analysis, gene set enrichment, two clustering methods and estimated relative leukocyte abundance using CIBERSORT. Results: Neutrophils, platelets, cytokine signaling, and the coagulation system were activated in COVID-19, and more pronounced in critical vs. non-critical disease. We observed two different trajectories of neutrophil-associated genes, indicating the emergence of a more immature neutrophil phenotype over time. Interferon-associated genes were strongly enriched in early COVID-19 before falling markedly, with modest severity-associated differences in trajectory. Conclusions: Severe COVID-19 is associated with a broad inflammatory response, which is more pronounced in critical disease. Our data suggest a progressively more immature circulating neutrophil phenotype over time. Interferon signaling is enriched in COVID-19 but does not seem to drive critical disease.
Project description:Neutrophils provide immune protection against pathogens but also may promote tissue injury in inflammatory diseases. Although neutrophils are generally considered as a relatively homogeneous population, evidence for heterogeneity is emerging. Under steady-state conditions, neutrophil heterogeneity may arise from ageing and the replenishment by newly released neutrophils from the bone marrow. We used microarray to globally analyze gene expression in aged neutrophils and characterize the inflammatory programs that are activated during the aging process in the circulation.
Project description:Preschool children with recurrent wheezing are heterogeneous, with differing responses to respiratory viral infections. Although neutrophils are crucial for host defense, their function has not been studied in this population. We performed functional immunophenotyping on isolated blood neutrophils from 52 preschool children with recurrent wheezing (aeroallergen sensitization, n=16; no sensitization, n=36). Blood neutrophils were purified and cultured overnight with polyinosinic:polycytidylic acid (poly(I:C)) as a viral analog stimulus. Neutrophils underwent next-generation sequencing with Reactome pathway analysis and were analyzed for cytokine secretion, apoptosis, myeloperoxidase and extracellular DNA release. CD14+ monocytes were also exposed to neutrophil culture supernatant and analyzed for markers of M1 and M2 activation. 495 genes, related largely to the innate immune system and neutrophil degranulation, were differently expressed in children with versus without aeroallergen sensitization. Functional experiments identified more neutrophil degranulation and extracellular trap formation (i.e., more myeloperoxidase and extracellular DNA) and less neutrophil pro-inflammatory cytokine secretion in children with aeroallergen sensitization. Neutrophils also shifted CD14+ monocytes to a more anti-inflammatory (i.e., M2) phenotype in sensitized children and a more pro-inflammatory (i.e., M1) phenotype in non-sensitized children. Although both groups experienced viral exacerbations, annualized exacerbation rates prompting unscheduled healthcare were also higher in children without aeroallergen sensitization after enrollment. Systemic neutrophil responses to viral infection differ by allergic phenotype and may be less effective in preschool children without allergic inflammation. Further studies of neutrophil function are needed in this population, which often has less favorable therapeutic responses to inhaled corticosteroids and other therapies directed at T2-high inflammation.
Project description:Peripheral blood neutrophils from periodontitis patients exhibit a hyper-reactive and hyper-active phenotype (collectively termed hyper-responsivity) in terms of production of reactive oxygen species (ROS) however the molecular basis for this observation is yet to be determined. Our objectives were to identify genes differentially expressed in hyper-responsive peripheral blood neutrophils from chronic periodontitis patients relative to periodontally healthy controls and use this data to identify potential contributory pathways to the hyper-responsive neutrophil phenotype.
Project description:Neutrophils provide immune protection against pathogens but also may promote tissue injury in inflammatory diseases. Although neutrophils are generally considered as a relatively homogeneous population, evidence for heterogeneity is emerging. Under steady-state conditions, neutrophil heterogeneity may arise from ageing and the replenishment by newly released neutrophils from the bone marrow. We used microarray to globally analyze gene expression in aged neutrophils and characterize the inflammatory programs that are activated during the aging process in the circulation. Control, aged and activated neutrophils were sorted directly from mouse blood for RNA extraction and hybridization on Affymetrix microarrays. We transfused whole blood and harvested donor neutrophils marked by the CD45.1 allele 6h later to derive neutrophils that had truly aged in vivo. Sorted neutrophils were compared to control donor neutrophils that had been transferred for only 10 min. Additionally, we harvested circulating neutrophils from TNF-? treated mice for comparison with neutrophils activated by systemic inflammation.
Project description:Peripheral blood neutrophils from periodontitis patients exhibit a hyper-reactive and hyper-active phenotype (collectively termed hyper-responsivity) in terms of production of reactive oxygen species (ROS) however the molecular basis for this observation is yet to be determined. Our objectives were to identify genes differentially expressed in hyper-responsive peripheral blood neutrophils from chronic periodontitis patients relative to periodontally healthy controls and use this data to identify potential contributory pathways to the hyper-responsive neutrophil phenotype. Experiment Overall Design: Neutrophils taken from 4 chronic periodontitis patients and age/sex matched healthy controls. RNA extracted and subsequently hybridised in dulpicate on to U133A arrays.
