Cigarette smoke exposure alters phosphodiesterases in human structural lung cells (original) (raw)
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American Journal of Physiology-Lung Cellular and Molecular Physiology, 2004
The expression profile of a panel of 15 cAMP phosphodiesterase isoforms was determined for inflammatory cell types of relevance to chronic obstructive pulmonary disease (COPD). In particular, the expression profiles for bronchoalveolar macrophages, peripheral blood monocytes, T lymphocytes, and neutrophils from smokers with and without COPD were compared. The phosphodiesterase expression profile was also analyzed for peripheral blood monocytes, T lymphocytes, and neutrophils from nonsmokers and compared with smokers. Qualitative RT-PCR identified transcripts for PDE4A10, PDE4A7, PDE4B1, PDE4B2, PDE4D1, and PDE4D2 isoforms as well as transcripts for both PDE3B and PDE7A in T cells, monocytes, and macrophages in all subjects. Transcripts for PDE4B3 and PDE4D4 were not observed in any of the cell types investigated. PDE4C was detected in all cells analyzed except for T cells. The long PDE4A4, PDE4D3, and PDE4D5 isoforms exhibited cell type-specific expression patterns. Semiquantitative...
Current pharmaceutical design, 2017
Chronic respiratory diseases affect millions of people every day. According to World Health Organization estimates, ~235 million people suffer from asthma, ~64 million suffer from chronic obstructive pulmonary disease (COPD), and millions more suffer from allergic rhinitis around the world. In recent last years, the first phosphodiesterase 4 (PDE4) inhibitor, roflumilast, was approved as a treatment to reduce the risk of exacerbations in stable and severe COPD associated with chronic bronchitis and a history of exacerbations. PDE4 exists as four subtypes (A, B, C, and D) each with a capacity to degrade cAMP, a second messenger involved in inflammatory responses. PDE4 inhibitors inhibit PDE4 activity, consequently increasing cAMP levels. This results in an anti-inflammatory effect, improving lung function. Roflumilast is a selective and non-specific PDE4 inhibitor, with the potential to inhibit all PDE4 isoforms to some degree. Despite the pharmacological effects of roflumilast, its ...
Pulmonary Pharmacology & Therapeutics, 2010
After more than two decades of research into phosphodiesterase 4 (PDE4) inhibitors, roflumilast (3-cyclopropylmethoxy-4-difluoromethoxy-N-[3,5-di-chloropyrid-4-yl]-benzamide) may become the first agent in this class to be approved for patient treatment worldwide. Within the PDE family of 11 known isoenzymes, roflumilast is selective for PDE4, showing balanced selectivity for subtypes A-D, and is of high subnanomolar potency. The active principle of roflumilast in man is its dichloropyridyl N-oxide metabolite, which has similar potency as a PDE4 inhibitor as the parent compound. The long half-life and high potency of this metabolite allows for once-daily, oral administration of a single, 500-microg tablet of roflumilast. The molecular mode of action of roflumilast--PDE4 inhibition and subsequent enhancement of cAMP levels--is well established. To further understand its functional mode of action in chronic obstructive pulmonary disease (COPD), for which roflumilast is being developed, a series of in vitro and in vivo preclinical studies has been performed. COPD is a progressive, devastating condition of the lung associated with an abnormal inflammatory response to noxious particles and gases, particularly tobacco smoke. In addition, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), significant extrapulmonary effects, including comorbidities, may add to the severity of the disease in individual patients, and which may be addressed preferentially by orally administered remedies. COPD shows an increasing prevalence and mortality, and its treatment remains a high, unmet medical need. In vivo, roflumilast mitigates key COPD-related disease mechanisms such as tobacco smoke-induced lung inflammation, mucociliary malfunction, lung fibrotic and emphysematous remodelling, oxidative stress, pulmonary vascular remodelling and pulmonary hypertension. In vitro, roflumilast N-oxide has been demonstrated to affect the functions of many cell types, including neutrophils, monocytes/macrophages, CD4+ and CD8+ T-cells, endothelial cells, epithelial cells, smooth muscle cells and fibroblasts. These cellular effects are thought to be responsible for the beneficial effects of roflumilast on the disease mechanisms of COPD, which translate into reduced exacerbations and improved lung function. As a multicomponent disease, COPD requires a broad therapeutic approach that might be achieved by PDE4 inhibition. However, as a PDE4 inhibitor, roflumilast is not a direct bronchodilator. In summary, roflumilast may be the first-in-class PDE4 inhibitor for COPD therapy. In addition to being a non-steroid, anti-inflammatory drug designed to target pulmonary inflammation, the preclinical pharmacology described in this review points to a broad functional mode of action of roflumilast that putatively addresses additional COPD mechanisms. This enables roflumilast to offer effective, oral maintenance treatment for COPD, with an acceptable tolerability profile and the potential to favourably affect the extrapulmonary effects of the disease.