Antigen stasis and airway nitrosative stress in human primary ciliary dyskinesia
Description
Introduction. Nasal NO (nNO) is low in most Primary Ciliary Dyskinesia (PCD) patients. Decreased ciliary motion could lead to antigen stasis, increasing oxidant production; and NO oxidation in the airways could both decrease gas phase NO and increase nitrosative stress. Materials and methods. We studied primary airway epithelial cells from healthy controls (HC) and patients with PCD. We measured antigen clearance in fenestrated membranes exposed apically to fluorescently- labeled antigen (Derp1-f). We immunoblotted for 3-nitrotyrosine (3 NT) and for oxidative response enzymes. We measured headspace NO above primary airway cells without and with a PCD-causing genotype. We measured nNO and exhaled breath condensate (EBC) H2O2 in vivo. Results. Apical Derp1-f was cleared from HC better than from PCD cells (DNAH11 and CCNO genotypes). DUOX1 expression was lower in HC than in PCD cells at baseline and after 24 hr Derp1-f exposure. HC cells had less 3-NT and NO3- than PCD cells. However, NO consumption by HC cells was less than that by PCD cells; NO loss was prevented by superoxide dismutase (SOD) and by apocynin. nNO was higher in HCs than in PCD patients. EBC H2O2 was lower in HC than in PCD patients. Conclusions. The PCD airway epithelium does not optimally clear antigens; and antigen exposure can lead to NO oxidation and nitrosative stress. Oxidation caused by antigen stasis could represent a therapeutic target in PCD, and there are convenient monitoring biomarkers.