title: Airway relaxant and anti-inflammatory properties of a PDE4 inhibitor with low affinity for the high-affinity rolipram binding site.
abstract: Inhibitors of phosphodiesterase 4 (PDE4) possess bronchospasmolytic and anti-inflammatory properties, which make them very attractive drugs for the treatment of asthma and COPD. Unfortunately, many PDE4 inhibitors also produce central nervous and gastrointestinal side effects, which have limited their clinical application. PDE4 has two binding sites for the archetypal PDE4 inhibitor rolipram, and it has been suggested that binding to the high-affinity rolipram binding site (HARBS) is responsible for the side effects of PDE4 inhibitors. Recently, we have synthesised the PDE4 inhibitor CC3 which shows low affinity to the HARBS. In the present study we investigated the bronchospasmolytic and anti-inflammatory properties of this novel compound in comparison to rolipram and the PDE3 inhibitor motapizone. The airway-relaxant properties of the PDE inhibitors were analysed in rat precision-cut lung slices (PCLS) in which airways were contracted by methacholine or in passively sensitised PCLS exposed to ovalbumin. The anti-inflammatory properties were investigated by measuring the release of TNF from endotoxin-treated human monocytes.Up to concentrations of 10 microM none of the PDE inhibitors significantly affected bronchoconstriction elicited by 10 microM methacholine. However, if rolipram or CC3 were given in combination with motapizone, methacholine-induced bronchoconstriction was concentration-dependently attenuated. Allergen-induced bronchoconstriction in passively sensitised PCLS was attenuated by CC3 (IC(50) 2.7 microM), rolipram (0.23 microM) and motapizone (8 microM). Combination of equimolar concentrations of motapizone and CC3 (0.34 microM) or rolipram (0.005 microM) showed an additive effect. Endotoxin-induced TNF release from human monocytes was attenuated by all three PDE inhibitors, i.e. CC3 (IC(50) 4.6 microM), rolipram (0.18 microM) and motapizone (5.8 microM). Our findings suggest that PDE4 inhibitors with only low affinity for the HABRS have bronchospasmolytic and anti-inflammatory properties.
authors.affiliation: Division of Pulmonary Pharmacology, Research Centre Borstel, Parkallee 22, 23845 Borstel, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Martin
authors.forename: Rolf
authors.initials: R
authors.lastname: Göggel
authors.forename: Vittorio
authors.initials: V
authors.lastname: Dal Piaz
authors.forename: Claudia
authors.initials: C
authors.lastname: Vergelli
authors.forename: Paola
authors.initials: P
authors.lastname: Giovannoni
authors.forename: Martin
authors.initials: M
authors.lastname: Ernst
authors.forename: Stefan
authors.initials: S
authors.lastname: Uhlig
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001667:Binding, Competitive; D016084:Bronchoconstriction / Q000187:drug effects*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D005260:Female; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D011760:Pyrrolidinones / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D020889:Rolipram / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D014409:Tumor Necrosis Factor-alpha; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D020889:Rolipram