title: Activity and expression of histone acetylases and deacetylases in inflammatory phenotypes of asthma.
abstract: BACKGROUND
  Histone acetyltransferases (HATs) and histone deacetylases (HDACs) regulate gene expression, yet differences in the activity of these enzymes in the inflammatory phenotypes of asthma are unknown. We hypothesized that neutrophilic asthma (NA) would be associated with increased HAT and decreased HDAC activity.
  
  
  OBJECTIVE
  To investigate total HAT/HDAC activity and gene expression in isolated blood monocytes and sputum macrophages from healthy and patients with asthma.
  
  
  METHODS
  Peripheral blood and induced sputum were collected from adults with asthma (n = 52) and healthy controls (n = 9). Sputum inflammatory cell counts were performed and asthma inflammatory phenotypes were classified according to sputum eosinophil and neutrophil cut-off's of > 3% and > 61% respectively. Peripheral blood monocytes were isolated (n = 61) and sputum macrophages were isolated from a subgroup of patients with asthma (n = 14), using immunomagnetic cell separation. RNA and nuclear proteins were extracted and quantified. Enzyme activity was assessed using fluorescent assays and gene expression of EP300, KAT2B, CREBBP, and HDACs 1, 2 and 3 were measured by qPCR.
  
  
  RESULTS
  There was a significant inverse association between blood monocyte HAT and HDAC activity (r = -0.58, P < 0.001). NA was associated with increased blood monocyte HAT enzyme activity (P = 0.02), decreased HDAC activity (P = 0.03), and increased HAT: HDAC ratio (P < 0.01) compared with eosinophilic asthma. There were no differences in gene expression of EP300, KAT2B, CREBBP, or HDACs 1, 2 and 3 in blood monocytes from subjects with asthma or inflammatory phenotypes of asthma. There was no effect of inhaled corticosteroid use, poor asthma control, or asthma severity on HAT/HDAC activities. Sputum macrophages had increased expression of KAT2B in eosinophilic compared with paucigranulocytic asthma.
  
  
  CONCLUSIONS
  Neutrophilic airway inflammation is associated with increased HAT and reduced HDAC activity in blood monocytes, demonstrating further systemic manifestations relating to the altered inflammatory gene transcription profile of neutrophilic asthma.
authors.affiliation: Priority Research Centre for Asthma and Respiratory Disease, Hunter Medical Research Institute, The University of Newcastle, Newcastle, NSW, Australia; Department of Respiratory & Sleep Medicine, HMRI, John Hunter Hospital, New Lambton, NSW, Australia.
authors.forename: L P
authors.initials: LP
authors.lastname: Gunawardhana
authors.forename: P G
authors.initials: PG
authors.lastname: Gibson
authors.forename: J L
authors.initials: JL
authors.lastname: Simpson
authors.forename: H
authors.initials: H
authors.lastname: Powell
authors.forename: K J
authors.initials: KJ
authors.lastname: Baines
mesh_terms: D000328:Adult; D000367:Age Factors; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics* / Q000276:immunology; D016022:Case-Control Studies; D004789:Enzyme Activation; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D051548:Histone Acetyltransferases / Q000235:genetics* / Q000378:metabolism*; D006655:Histone Deacetylases / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D010641:Phenotype; D012720:Severity of Illness Index; D013183:Sputum / Q000166:cytology / Q000276:immunology
chemical_list: D018927:Anti-Asthmatic Agents; D051548:Histone Acetyltransferases; D006655:Histone Deacetylases
keywords: HAT; HDAC; asthma; inflammatory phenotypes; monocytes; sputum