fenretinide and Pseudomonas-Infections

Cystic fibrosis (CF) is the most common genetic disease in Caucasians. CF is manifested by abnormal accumulation of mucus in the lungs, which serves as fertile ground for the growth of microorganisms leading to recurrent infections and ultimately, lung failure. Mucus in CF patients consists of DNA from dead neutrophils as well as mucins produced by goblet cells. MUC5AC mucin leads to pathological plugging of the airways whereas MUC5B has a protective role against bacterial infection. Therefore, decreasing the level of MUC5AC while maintaining MUC5B intact would in principle be a desirable mucoregulatory treatment outcome. Fenretinide prevented the lipopolysaccharide-induced increase of MUC5AC gene expression, without affecting the level of MUC5B, in a lung goblet cell line. Additionally, fenretinide treatment reversed the pro-inflammatory imbalance of fatty acids by increasing docosahexaenoic acid and decreasing the levels of arachidonic acid in a lung epithelial cell line and primary leukocytes derived from CF patients. Furthermore, for the first time we also demonstrate the effect of fenretinide on multiple unsaturated fatty acids, as well as differential effects on the levels of long- compared to very-long-chain saturated fatty acids which are important substrates of complex phospholipids. Finally, we demonstrate that pre-treating mice with fenretinide in a chronic model of P. aeruginosa lung infection efficiently decreases the accumulation of mucus. These findings suggest that fenretinide may offer a new approach to therapeutic modulation of pathological mucus production in CF.

Topics: Administration, Oral; Animals; Arachidonic Acid; Cell Line; Cystic Fibrosis; Disease Models, Animal; Docosahexaenoic Acids; Fenretinide; Humans; Lung; Mice; Mice, Inbred CFTR; Mucin 5AC; Mucin-5B; Mucus; Phospholipids; Pneumonia; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Respiratory Mucosa

Patients with cystic fibrosis (CF) and Cftr-knockout mice (CF mice) display an imbalance in fatty acids, with high arachidonic acid (AA) and low docosahexaenoic acid (DHA) concentrations. Our recent studies demonstrated defects in another class of lipids, ceramides, in patients with CF and in CF mice. This study investigates the relationship between ceramide, AA, DHA, and the correction of lipid imbalances in CF mice after treatment with fenretinide. Concentrations of AA, DHA, and ceramide were assessed in plasma from 58 adult patients with CF and 72 healthy control subjects. After 28 days of treatment with fenretinide, the same analysis was performed in wild-type and CF mice from plasma and organs (lung, ileum, pancreas, and liver). Low ceramide levels were associated with high AA and low DHA concentrations in patients with CF. No correlation was observed in healthy control subjects. Greater deficiencies were seen in patients with CF who were diagnosed before the age of 18, specifically with statistically significant higher levels of AA. Treatment with fenretinide (N-(4-hydroxyphenyl)retinamide; 4-HPR) normalized high levels of AA and low levels of ceramide, and increased the levels of DHA in CF mice. As in patients with CF, low ceramide levels correlated with higher AA and lower DHA levels in plasma of CF mice. Lipid abnormalities correlated with ceramide deficiencies in patients with CF and CF mice. We found that fenretinide treatment normalizes the fatty acid imbalance in CF mice with reducing AA to WT levels and increasing DHA. We propose that fenretinide treatment might improve this pathological phenotype in patients with CF.

Topics: Adolescent; Adult; Aged; Animals; Arachidonic Acid; Case-Control Studies; Ceramides; Cystic Fibrosis; Disease Models, Animal; Docosahexaenoic Acids; Female; Fenretinide; Forced Expiratory Volume; Humans; Ileum; Liver; Lung; Male; Mice; Mice, Inbred CFTR; Middle Aged; Pancreas; Pseudomonas aeruginosa; Pseudomonas Infections; Severity of Illness Index; Young Adult

Chronic and persistent lung infections cause the majority of morbidity and mortality in patients with cystic fibrosis (CF). Galactosyl ceramide has been previously shown to be involved in Pseudomonas internalization. Therefore, we assessed ceramide levels in the plasma of patients with CF and compared them to healthy volunteers using high-performance liquid chromatography followed by mass spectrometry. Our results demonstrate that patients with CF display significantly lower levels of several ceramide sphingolipid species, specifically C14:0, C20:1, C22:0, C22:1, and C24:0 ceramides, and dihydroxy ceramide (DHC16:0). We report that Cftr-knockout mice display diminished ceramide levels in CF-related organs (lung, pancreas, ileum, and plasma) compared with their littermate controls. Since it has been previously reported that in vitro treatment with fenretinide induced ceramide in neuroblastoma cell lines, we decided to test this drug in vivo using our Cftr-knockout mice in an attempt to correct this newly identified defect in ceramide levels. We demonstrate that treatment with fenretinide is able to increase ceramide concentrations in CF-related organs. We further assessed the biological effect of fenretinide on the ability of Cftr-knockout mice to combat lung infection with P. aeruginosa. Our data show dramatic improvement in the ability of Cftr-knockout mice to control P. aeruginosa infection. Overall, these findings not only document a novel deficiency in several ceramide species in patients with CF, but also demonstrate a pharmacologic means to correct this defect in Cftr-knockout mice. Our data provide a strong rationale for clinical intervention that may benefit patients with CF suffering from CF lung disease.

Topics: Adult; Animals; Anticarcinogenic Agents; Cell Line, Tumor; Ceramides; Chromatography, High Pressure Liquid; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Fenretinide; Humans; Male; Mass Spectrometry; Mice; Mice, Inbred CFTR; Mice, Knockout; Middle Aged; Organ Specificity; Pseudomonas aeruginosa; Pseudomonas Infections; Sphingolipids