acyclovir and Cystic-Fibrosis

Small molecules that correct the folding defects and enhance surface localization of the F508del mutation in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) comprise an important therapeutic strategy for cystic fibrosis lung disease. However, compounds that rescue the F508del mutant protein to wild type (WT) levels have not been identified. In this report, we consider obstacles to obtaining robust and therapeutically relevant levels of F508del CFTR. For example, markedly diminished steady state amounts of F508del CFTR compared to WT CFTR are present in recombinant bronchial epithelial cell lines, even when much higher levels of mutant transcript are present. In human primary airway cells, the paucity of Band B F508del is even more pronounced, although F508del and WT mRNA concentrations are comparable. Therefore, to augment levels of "repairable" F508del CFTR and identify small molecules that then correct this pool, we developed compound library screening protocols based on automated protein detection. First, cell-based imaging measurements were used to semi-quantitatively estimate distribution of F508del CFTR by high content analysis of two-dimensional images. We evaluated ~2,000 known bioactive compounds from the NIH Roadmap Molecular Libraries Small Molecule Repository in a pilot screen and identified agents that increase the F508del protein pool. Second, we analyzed ~10,000 compounds representing diverse chemical scaffolds for effects on total CFTR expression using a multi-plate fluorescence protocol and describe compounds that promote F508del maturation. Together, our findings demonstrate proof of principle that agents identified in this fashion can augment the level of endoplasmic reticulum (ER) resident "Band B" F508del CFTR suitable for pharmacologic correction. As further evidence in support of this strategy, PYR-41-a compound that inhibits the E1 ubiquitin activating enzyme-was shown to synergistically enhance F508del rescue by C18, a small molecule corrector. Our combined results indicate that increasing the levels of ER-localized CFTR available for repair provides a novel route to correct F508del CFTR.

Topics: Alleles; Benzoates; Cells, Cultured; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Endoplasmic Reticulum; Furans; Gene Deletion; HEK293 Cells; HeLa Cells; High-Throughput Screening Assays; Humans; Hydroxamic Acids; Microscopy, Fluorescence; Protein Folding; Protein Structure, Tertiary; Pyrazoles; RNA, Messenger; Small Molecule Libraries; Ubiquitination; Vorinostat

This study reports the development of lymphocytic myocarditis in a bilateral lung allograft recipient. A 23-year-old woman developed congestive heart failure and severe left ventricular dysfunction 32 months after a bilateral lung allograft for cystic fibrosis. She had taken oral acyclovir for infectious mononucleosis that was diagnosed 11 months previously. Her viral load for Epstein-Barr virus (EBV) increased, and an echocardiogram revealed a left ventricular ejection fraction of 25% and endomyocardial biopsy revealed lymphocytic myocarditis. She received valacyclovir (1 g x 3 times daily) and made a full recovery 6 months later.

Topics: Acyclovir; Adult; Antiviral Agents; Biopsy, Needle; Cystic Fibrosis; Female; Follow-Up Studies; Heart Failure; Humans; Immunohistochemistry; Infectious Mononucleosis; Lung Transplantation; Lymphocytes; Myocarditis; Risk Assessment; Severity of Illness Index; Treatment Outcome; Valacyclovir; Valine

Of 159 adult patients with cystic fibrosis, 5 were documented to have varicella-zoster infection that resulted in an infective pulmonary exacerbation that required intravenous acyclovir and additional antibiotic treatment. Stable serial pulmonary function values were observed over a 1-year period in 4 patients and no complications resulted from treatment. Early treatment with acyclovir in combination with appropriate antibiotics may prevent pulmonary deterioration in adult patients with cystic fibrosis who develop varicella-zoster infection.

Topics: Acyclovir; Adolescent; Adult; Chickenpox; Cystic Fibrosis; Female; Herpes Zoster; Humans; Male; Pseudomonas Infections; Respiratory Function Tests; Respiratory Tract Infections