Usage Information
Citation Information: JCI Insight. 2018;3(4):e93029. https://doi.org/10.1172/jci.insight.93029.
Abstract
Traditional pulmonary therapies for cystic fibrosis (CF) target the downstream effects of CF transmembrane conductance regulator (CFTR) dysfunction (the cause of CF). Use of one such therapy, β-adrenergic bronchodilators (such as albuterol), is nearly universal for airway clearance. Conversely, novel modulator therapies restore function to select mutant CFTR proteins, offering a disease-modifying treatment. Recent trials of modulators targeting F508del-CFTR, the most common CFTR mutation, suggest that chronic β-agonist use may undermine clinical modulator benefits. We therefore sought to understand the impact of chronic or excess β-agonist exposure on CFTR activation in human airway epithelium. The present studies demonstrate a greater than 60% reduction in both wild-type and modulator-corrected F508del-CFTR activation following chronic exposure to short- and long-acting β-agonists. This reduction was due to reduced cellular generation of cAMP downstream of the β-2 adrenergic receptor–G protein complex. Our results point towards a posttranscriptional reduction in adenylyl cyclase function as the mechanism of impaired CFTR activation produced by prolonged β-agonist exposure. β-Agonist–induced CFTR dysfunction was sufficient to abrogate VX809/VX770 modulation of F508del-CFTR in vitro. Understanding the clinical relevance of our observations is critical for CF patients using these drugs, and for investigators to inform future CFTR modulator drug trials.
Authors
John J. Brewington, Jessica Backstrom, Amanda Feldman, Elizabeth L. Kramer, Jessica D. Moncivaiz, Alicia J. Ostmann, Xiaoting Zhu, L. Jason Lu, John P. Clancy
Usage data is cumulative from December 2022 through December 2023.
| Usage | JCI | PMC |
|---|---|---|
| Text version | 253 | 70 |
| 27 | 16 | |
| Figure | 79 | 1 |
| Table | 10 | 0 |
| Supplemental data | 4 | 1 |
| Citation downloads | 21 | 0 |
| Totals | 394 | 88 |
| Total Views | 482 | |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.
