Brain natriuretic peptide protects against hyperresponsiveness of human asthmatic airway smooth muscle via an epithelial cell-dependent mechanism.
Brain natriuretic peptide (BNP) relaxes airways by activating natriuretic peptide receptor-A and elevating cyclic guanosine monophosphate. BNP is more effective in passively sensitized human bronchi compared with control airways. The molecular and cellular patterns involved in this signaling are unknown. The aim of this study was to investigate the influence of BNP on airway smooth muscle (ASM) cells obtained from donors with asthma and healthy donors and to identify the mechanisms involved in BNP-mediated relaxation. The contractile response of ASM cells was microscopically assessed in vitro in the presence of 1 μM BNP or with supernatant from human bronchial epithelial (BEAS-2B) cells pretreated with 1 μM BNP. We investigated the role of muscarinic M2 receptors and inducible nitric oxide synthase (iNOS), quantified the release of acetylcholine and nitric oxide (NO), and assessed the gene/protein expression of iNOS and myosin phosphatase target subunit 1 (MYPT1). Supernatant from BEAS-2B cells treated with BNP reduced the hyperreactivity of asthmatic ASM cells by shifting the potency of histamine by 1.19-fold but had no effect in healthy ASM cells. BNP was not effective directly on ASM cells. Blocking muscarinic M2-receptors and iNOS abolished the protective role of supernatant from BEAS-2B treated with BNP. BNP stimulated the release of acetylcholine (210.7 ± 11.1%) from BEAS-2B cells that in turn increased MYPT1 and iNOS gene/protein expression and enhanced NO levels in asthmatic ASM supernatant (35.0 ± 13.0%). This study provides evidence that BNP protects against bronchial hyperresponsiveness via an interaction between respiratory epithelium and ASM in subjects with asthma.
1 Department of Pulmonary Rehabilitation, San Raffaele Pisana Hospital, IRCCS, Rome, Italy.
Luigino
L
Calzetta
Daniela
D
Passeri
Varsha
V
Kanabar
Paola
P
Rogliani
Clive
C
Page
Mario
M
Cazzola
Maria Gabriella
MG
Matera
Augusto
A
Orlandi
D000109:Acetylcholine / Q000378:metabolism; D018927:Anti-Asthmatic Agents / Q000494:pharmacology*; D001249:Asthma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D016535:Bronchial Hyperreactivity / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D016084:Bronchoconstriction / Q000187:drug effects*; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D016022:Case-Control Studies; D002450:Cell Communication / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase / Q000235:genetics / Q000378:metabolism; D020097:Natriuretic Peptide, Brain / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D043585:Receptor, Muscarinic M2 / Q000187:drug effects / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D018927:Anti-Asthmatic Agents; D016085:Bronchoconstrictor Agents; D017077:Culture Media, Conditioned; D043585:Receptor, Muscarinic M2; D020097:Natriuretic Peptide, Brain; D009569:Nitric Oxide; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D043263:Myosin-Light-Chain Phosphatase; C490372:PPP1R12A protein, human; D000109:Acetylcholine