RT Journal Article
SR Electronic
T1 Airway epithelial hemoglobin β regulates ciliary endothelial NOS
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P574
VO 42
IS Suppl 57
A1 Nadzeya Marozkina
A1 Giovanni Piedimonte
A1 Lesly Cottrell
A1 Vinod Jyothikumar
A1 Amasi Periasamy
A1 Khalequz Zaman
A1 Adam Straub
A1 Scott Randell
A1 Benjamin Gaston
YR 2013
UL http://erj.ersjournals.com/content/42/Suppl_57/P574.abstract
AB Introduction: Patients with primary ciliary dyskinesia (PCD) and asthmatic obesity can have airway inflammation but low FENO. Endothelial hemoglobin (Hb) α and metHb reductase (MetHbR) expression (Straub, Nature, 2012) regulate eNOS: Hb-Fe2+/eNOS forms inert NO3-, while Fe3+/eNOS form active NO and S-nitrosothiols (SNOs). Thus, we studied whether airway ciliary eNOS was regulated by Hb and MetHbR.Methods. Hb, MetHbR, eNOS, and TRPV 4 were visualized by confocal microscopy (CFM) and immunofluorescence (IF); Ca2+ flux by CFM; and NADH autofluorescence by 2-photon. SNOs, NO2- and NO3- assays used reductive chemiluminescence. Human pseudostrutified airway epithelial cells at air-liquid interface (HAE-ALI) were exposed to airway cyclic compressive stress (CCS). Breath condensate (BC) was from 65 school children.Results. TRPV4 was in cilia, eNOS and Hb β (but not α) were at the base of cilia; MetHbR was cytosolic. Both CCS and Ca2+ ionophore caused Ca2+ flux into HAE through TRPV4, activating eNOS to triple SNO levels; this was prevented by NOS inhibition (p < 0.01). Glucose increased NADH, leading to Hb reduction (NOS product NO3-, not NO or SNO). Obese asthmatic children had higher BC NO3- (mean, 10.6 μM) than non-obese asthmatics (7.6), or than obese (6.0) or non-obese (2.5) controls.Conclusions. HAE stretch allows Ca2+ entry, activating ciliary eNOS. Whether eNOS produces bioactive NO and SNOs or inert NO3- depends on MetHbR: high glucose favors Hb β reduction/NO3-. Thus, asthmatics with high glucose will oxidize airway NO. Decreased exercise should also lead to decreased CCS in vivo, decreasing eNOS activity. This may explain low FENO and high airway NO3- in obese asthma patients, as well as low FENO in PCD.