title: Role of the nitric oxide-soluble guanylyl cyclase pathway in obstructive airway diseases.
abstract: Nitric oxide (NO) is a gaseotransmitter, which is involved in many signaling processes in health and disease. Three enzymes generate NO from l-arginine, with citrulline formed as a by-product: neuronal NO synthase (nNOS or NOS1), endothelial NOS (eNOS or NOS3) and inducible NOS (iNOS or NOS2). NO is a ligand of soluble guanylyl cyclase (sGC), an intracellular heterodimer enzyme that catalyzes the conversion of guanosine triphosphate (GTP) to cyclic GMP (cGMP). cGMP further activates protein kinase G that eventually reduces the smooth muscle tone in bronchi or vessels. Phosphodiesterase 5 (PDE5) degrades cGMP to GMP. However, NO reacts with superoxide anion (O2(-)), leading to formation of the pro-inflammatory molecule peroxynitrite. Under physiological conditions, NO plays a homeostatic bronchoprotective role in healthy subjects. In obstructive airway diseases, NO can be beneficial by its bronchodilating effect, but could also be detrimental by the formation of peroxynitrite. Since asthma and COPD are associated with increased levels of exhaled NO, chronic inflammation and increased airway smooth muscle tone, the NO/sGC/cGMP pathway could be involved in these highly prevalent obstructive airway diseases. Here we review the involvement of NO, NO synthases, guanylyl cyclases, cGMP and phophodiesterase-5 in asthma and COPD and potential therapeutic approaches to modulate this pathway.
authors.affiliation: Laboratory for Translational Research in Obstructive Pulmonary Diseases, Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Dupont
authors.affiliation: George P. Livanos and Marianthi Simou Laboratories, Evangelismos Hospital, 1st Department of Pulmonary and Critical Care, University of Athens, Athens, Greece; Laboratory of Molecular Pharmacology, Department of Pharmacy, University of Patras, Patras, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Glynos
authors.affiliation: Laboratory for Translational Research in Obstructive Pulmonary Diseases, Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Ken R
authors.initials: KR
authors.lastname: Bracke
authors.affiliation: Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium; Department of Molecular Biomedical Research, VIB, Ghent, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Brouckaert
authors.affiliation: Laboratory for Translational Research in Obstructive Pulmonary Diseases, Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium. Electronic address: guy.brusselle@ugent.be.
authors.forename: Guy G
authors.initials: GG
authors.lastname: Brusselle
mesh_terms: D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D006152:Cyclic GMP / Q000378:metabolism; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5 / Q000378:metabolism; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D000071756:Soluble Guanylyl Cyclase; D013481:Superoxides / Q000378:metabolism
chemical_list: D018160:Receptors, Cytoplasmic and Nuclear; D013481:Superoxides; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP
keywords: Asthma; COPD; Nitric oxide; Soluble guanylyl cyclase