@article {MarozkinaP574, author = {Nadzeya Marozkina and Giovanni Piedimonte and Lesly Cottrell and Vinod Jyothikumar and Amasi Periasamy and Khalequz Zaman and Adam Straub and Scott Randell and Benjamin Gaston}, title = {Airway epithelial hemoglobin β regulates ciliary endothelial NOS}, volume = {42}, number = {Suppl 57}, elocation-id = {P574}, year = {2013}, publisher = {European Respiratory Society}, abstract = {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.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/42/Suppl_57/P574}, eprint = {https://erj.ersjournals.com/content/42/Suppl_57/P574.full.pdf}, journal = {European Respiratory Journal} }