Recombinant Acid Ceramidase Reduces Inflammation and Infection in Cystic Fibrosis

Abstract

Rationale: In cystic fibrosis the major cause of morbidity and mortality is lung disease characterized by inflammation and infection. The influence of sphingolipid metabolism is poorly understood with a lack of studies using human airway model systems. Objectives: To investigate sphingolipid metabolism in cystic fibrosis and the effects of treatment with recombinant human acid ceramidase on inflammation and infection. Methods: Sphingolipids were measured using mass spectrometry in fully differentiated cultures of primary human airway epithelial cells and cocultures with Pseudomonas aeruginosa. In situ activity assays, Western blotting, and quantitative PCR were used to investigate function and expression of ceramidase and sphingomyelinase. Effects of treatment with recombinant human acid ceramidase on sphingolipid profile and inflammatory mediator production were assessed in cell cultures and murine models. Measurements and Main Results: Ceramide is increased in cystic fibrosis airway epithelium owing to differential function of enzymes regulating sphingolipid metabolism. Sphingosine, a metabolite of ceramide with antimicrobial properties, is not upregulated in response to P. aeruginosa by cystic fibrosis airway epithelia. Tumor necrosis factor receptor 1 is increased in cystic fibrosis epithelia and activates NF-kB signaling, generating inflammation. Treatment with recombinant human acid ceramidase, to decrease ceramide, reduced both inflammatory mediator production and susceptibility to infection. Conclusions: Sphingolipid metabolism is altered in airway epithelial cells cultured from people with cystic fibrosis. Treatment with recombinant acid ceramidase ameliorates the two pivotal features of cystic fibrosis lung disease, inflammation and infection, and thus represents a therapeutic approach worthy of further exploration.

Sphingolipid composition of circulating extracellular vesicles after myocardial ischemia

“…www.nature.com/scientificreports/ group is in line with the reference range of circulating sphingolipid in human plasma from healthy subjects 41 , our study suffers of limited numerosity of included patients, which can partially explain this discrepancy. Moreover study design and blood sampling modality (different anticoagulants) may influence LC-MS/MS results 41,42 . Notably, the increase of different ceramide species has been shown to concur to the upregulation of different acute phase proteins, and to leucocytes recruitment and activation [43][44][45] .…”

“…Although the concentration sphingolipid species in control group is in line with the reference range of circulating sphingolipid in human plasma from healthy subjects 41 , our study suffers of limited numerosity of included patients, which can partially explain this discrepancy. Moreover study design and blood sampling modality (different anticoagulants) may influence LC–MS/MS results 41 , 42 .…”

Interferon regulatory factor 8 regulates expression of acid ceramidase and infection susceptibility in cystic fibrosis

“…In contrast to sphingosine, studies from several laboratories have demonstrated that ceramide levels are higher in CF epithelial cells than in normal cells (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). The imbalance between ceramide and sphingosine in the respiratory tract was shown to be mediated by a down-regulation of the acid ceramidase protein expression correlating with a marked reduction of the activity of the acid ceramidase in tracheal and bronchial epithelial cells of mice and humans (9,19).…”

Acid Ceramidase Rescues Cystic Fibrosis Mice from Pulmonary Infections

“…We and others have recently reported that the lipid composition of CF airway epithelial cells is significantly altered with an increase of ceramide and a decrease of sphingosine in the luminal membrane of tracheal and bronchial epithelial cells (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”