Measurement of IL-13-induced iNOS-derived gas phase nitric oxide in human bronchial epithelial cells

Am J Respir Cell Mol Biol. 2007 Jul;37(1):97-104. doi: 10.1165/rcmb.2006-0419OC. Epub 2007 Mar 8.


Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl.s(-1.)cm(-2)) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air-liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 +/- 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13-stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Air
  • Asthma / metabolism
  • Bronchi / cytology*
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Epithelial Cells / cytology*
  • Humans
  • Hypersensitivity
  • Inflammation
  • Interleukin-13 / metabolism*
  • Nitrates / chemistry
  • Nitrates / metabolism
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase Type II / metabolism*
  • Nitrites / metabolism
  • Time Factors


  • Interleukin-13
  • Nitrates
  • Nitrites
  • Nitric Oxide
  • Nitric Oxide Synthase Type II