title: Acid sphingomyelinase inhibitors normalize pulmonary ceramide and inflammation in cystic fibrosis.
abstract: Employing genetic mouse models we have recently shown that ceramide accumulation is critically involved in the pathogenesis of cystic fibrosis (CF) lung disease. Genetic or systemic inhibition of the acid sphingomyelinase (Asm) is not feasible for treatment of patients or might cause adverse effects. Thus, a manipulation of ceramide specifically in lungs of CF mice must be developed. We tested whether inhalation of different acid sphingomyelinase inhibitors does reduce Asm activity and ceramide accumulation in lungs of CF mice. The efficacy and specificity of the drugs was determined. Ceramide was determined by mass spectrometry, DAG-kinase assays, and fluorescence microscopy. We determined pulmonary and systemic Asm activity, neutral sphingomyelinase (Nsm), ceramide, cytokines, and infection susceptibility. Mass spectroscopy, DAG-kinase assays, and semiquantitative immune fluorescence microscopy revealed that a standard diet did not influence ceramide in bronchial respiratory epithelial cells, while a diet with Peptamen severely affected the concentration of sphingolipids in CF lungs. Inhalation of the Asm inhibitors amitriptyline, trimipramine, desipramine, chlorprothixene, fluoxetine, amlodipine, or sertraline restored normal ceramide concentrations in murine bronchial epithelial cells, reduced inflammation in the lung of CF mice and prevented infection with Pseudomonas aeruginosa. All drugs showed very similar efficacy. Inhalation of the drugs was without systemic effects and did not inhibit Nsm. These findings employing several structurally different Asm inhibitors identify Asm as primary target in the lung to reduce ceramide concentrations. Inhaling an Asm inhibitor may be a beneficial treatment for CF, with minimal adverse systemic effects.
authors.affiliation: Professor and Chair, Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, D-45122 Essen, Germany.
authors.forename: Katrin Anne
authors.initials: KA
authors.lastname: Becker
authors.forename: Joachim
authors.initials: J
authors.lastname: Riethmüller
authors.forename: Anja
authors.initials: A
authors.lastname: Lüth
authors.forename: Gerd
authors.initials: G
authors.lastname: Döring
authors.forename: Burkhard
authors.initials: B
authors.lastname: Kleuser
authors.forename: Erich
authors.initials: E
authors.lastname: Gulbins
mesh_terms: D000280:Administration, Inhalation; D000284:Administration, Oral; D000375:Aging; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002518:Ceramides / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology; D016207:Cytokines / Q000378:metabolism; D019852:Diacylglycerol Kinase / Q000378:metabolism; D004195:Disease Models, Animal; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D008168:Lung / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D013058:Mass Spectrometry; D051379:Mice; D018181:Mice, Inbred CFTR; D008856:Microscopy, Fluorescence; D009842:Oligopeptides / Q000008:administration & dosage; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D011014:Pneumonia / Q000150:complications / Q000188:drug therapy* / Q000201:enzymology / Q000276:immunology; D011552:Pseudomonas Infections / Q000201:enzymology / Q000276:immunology / Q000517:prevention & control; D020545:Respiratory Mucosa / Q000187:drug effects / Q000201:enzymology / Q000276:immunology; D012141:Respiratory Tract Infections / Q000201:enzymology / Q000276:immunology / Q000517:prevention & control; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D000893:Anti-Inflammatory Agents; D002518:Ceramides; D016207:Cytokines; D018836:Inflammation Mediators; D009842:Oligopeptides; C073248:Peptamen; D010726:Phosphodiesterase Inhibitors; D019852:Diacylglycerol Kinase; D013108:Sphingomyelin Phosphodiesterase