{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T00:38:21Z","timestamp":1759970301226,"version":"build-2065373602"},"reference-count":40,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2025,1,8]],"date-time":"2025-01-08T00:00:00Z","timestamp":1736294400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Institutes of Health","award":["R01HL155325","BRATCH21I0"],"award-info":[{"award-number":["R01HL155325","BRATCH21I0"]}]},{"DOI":"10.13039\/100000897","name":"Cystic Fibrosis Foundation","doi-asserted-by":"publisher","award":["R01HL155325","BRATCH21I0"],"award-info":[{"award-number":["R01HL155325","BRATCH21I0"]}],"id":[{"id":"10.13039\/100000897","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Easton M. Crawford Charitable Lead Unitrust","award":["R01HL155325","BRATCH21I0"],"award-info":[{"award-number":["R01HL155325","BRATCH21I0"]}]},{"name":"Department of Pediatrics at National Jewish Health","award":["R01HL155325","BRATCH21I0"],"award-info":[{"award-number":["R01HL155325","BRATCH21I0"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel that is dysfunctional in individuals with cystic fibrosis (CF). The permeability of CFTR can be experimentally manipulated though different mechanisms, including activation via inducing the phosphorylation of residues in the regulatory domain as well as altering the gating\/open probability of the channel. Phosphorylation\/activation of the channel is achieved by exposure to compounds that increase intracellular cAMP, with forskolin and IBMX commonly used for this purpose. Cact-A1 is a unique CFTR activator that does not increase intracellular cAMP, and VX-770 (ivacaftor) is a CFTR potentiator that is used experimentally and therapeutically to increase the open probability of the channel. Using primary human nasal epithelial cell (HNEC) cultures and Fischer rat thyroid (FRT) epithelial cells exogenously expressing functional CFTR, we examined the impact of VX-770, Cact-A1, and forskolin\/IBMX on CFTR activity during analysis in an Ussing chamber. Relative contributions of these compounds to maximal CFTR activity were dependent on order of exposure, the presence of chemical and electrical gradients, the level of constitutive CFTR function, and the cell model tested. Increasing intracellular cAMP appeared to change cellular functions outside of CFTR activity that resulted in alterations in the drive for chloride through CFTR. These results demonstrate that one can utilize combinations of small-molecule CFTR activators and potentiators to provide detailed characterization of CFTR-mediated ion transport in primary HNECs and properties of these modulators in both primary HNECs and FRT cells. Future studies using these approaches may assist in the identification of novel defects in CFTR function and the identification of modulators with unique impacts on CFTR-mediated ion transport.<\/jats:p>","DOI":"10.3390\/ijms26020471","type":"journal-article","created":{"date-parts":[[2025,1,8]],"date-time":"2025-01-08T07:40:13Z","timestamp":1736322013000},"page":"471","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["VX-770, Cact-A1, and Increased Intracellular cAMP Have Distinct Acute Impacts upon CFTR Activity"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7853-6302","authenticated-orcid":false,"given":"Heidi J.","family":"Nick","sequence":"first","affiliation":[{"name":"Department of Pediatrics, National Jewish Health, Denver, CO 80206, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah E.","family":"Christeson","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, National Jewish Health, Denver, CO 80206, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2240-8632","authenticated-orcid":false,"given":"Preston E.","family":"Bratcher","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, National Jewish Health, Denver, CO 80206, USA"},{"name":"Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,1,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1038\/nrg3849","article-title":"Cystic fibrosis genetics: From molecular understanding to clinical application","volume":"16","author":"Cutting","year":"2015","journal-title":"Nat. Rev. Genet."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.jcf.2018.05.004","article-title":"CFTR modulator theratyping: Current status, gaps and future directions","volume":"18","author":"Clancy","year":"2019","journal-title":"J. Cyst. Fibros."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"S13","DOI":"10.1002\/ppul.24547","article-title":"Cystic fibrosis precision therapeutics: Emerging considerations","volume":"54","author":"Joshi","year":"2019","journal-title":"Pediatr. Pulmonol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"18825","DOI":"10.1073\/pnas.0904709106","article-title":"Rescue of CF airway epithelial cell function in vitro by a CFTR potentiator, VX-770","volume":"106","author":"Hadida","year":"2009","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.jcf.2013.06.008","article-title":"Effect of ivacaftor on CFTR forms with missense mutations associated with defects in protein processing or function","volume":"13","author":"Yu","year":"2014","journal-title":"J. Cyst. Fibros."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1016\/j.jcf.2011.12.005","article-title":"Ivacaftor potentiation of multiple CFTR channels with gating mutations","volume":"11","author":"Yu","year":"2012","journal-title":"J. Cyst. Fibros."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1991","DOI":"10.1056\/NEJMoa0909825","article-title":"Effect of VX-770 in persons with cystic fibrosis and the G551D-CFTR mutation","volume":"363","author":"Accurso","year":"2010","journal-title":"N. Engl. J. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1663","DOI":"10.1056\/NEJMoa1105185","article-title":"A CFTR potentiator in patients with cystic fibrosis and the G551D mutation","volume":"365","author":"Ramsey","year":"2011","journal-title":"N. Engl. J. Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1219","DOI":"10.1164\/rccm.201301-0153OC","article-title":"Efficacy and safety of ivacaftor in patients aged 6 to 11 years with cystic fibrosis with a G551D mutation","volume":"187","author":"Davies","year":"2013","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/j.jcf.2018.04.004","article-title":"Effectiveness of ivacaftor in cystic fibrosis patients with non-G551D gating mutations","volume":"18","author":"Guimbellot","year":"2019","journal-title":"J. Cyst. Fibros."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"674","DOI":"10.1016\/j.jcf.2014.09.005","article-title":"Efficacy and safety of ivacaftor in patients with cystic fibrosis and a non-G551D gating mutation","volume":"13","author":"Munck","year":"2014","journal-title":"J. Cyst. Fibros."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1612","DOI":"10.1056\/NEJMoa1807120","article-title":"VX-445-Tezacaftor-Ivacaftor in Patients with Cystic Fibrosis and One or Two Phe508del Alleles","volume":"379","author":"Keating","year":"2018","journal-title":"N. Engl. J. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1940","DOI":"10.1016\/S0140-6736(19)32597-8","article-title":"Efficacy and safety of the elexacaftor plus tezacaftor plus ivacaftor combination regimen in people with cystic fibrosis homozygous for the F508del mutation: A double-blind, randomised, phase 3 trial","volume":"394","author":"Heijerman","year":"2019","journal-title":"Lancet"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1809","DOI":"10.1056\/NEJMoa1908639","article-title":"Elexacaftor-Tezacaftor-Ivacaftor for Cystic Fibrosis with a Single Phe508del Allele","volume":"381","author":"Middleton","year":"2019","journal-title":"N. Engl. J. Med."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1016\/S2213-2600(14)70132-8","article-title":"A CFTR corrector (lumacaftor) and a CFTR potentiator (ivacaftor) for treatment of patients with cystic fibrosis who have a phe508del CFTR mutation: A phase 2 randomised controlled trial","volume":"2","author":"Boyle","year":"2014","journal-title":"Lancet Respir. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2013","DOI":"10.1056\/NEJMoa1709846","article-title":"Tezacaftor-Ivacaftor in Patients with Cystic Fibrosis Homozygous for Phe508del","volume":"377","author":"Munck","year":"2017","journal-title":"N. Engl. J. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"707","DOI":"10.1152\/physrev.00007.2018","article-title":"Structure, Gating, and Regulation of the Cftr Anion Channel","volume":"99","author":"Csanady","year":"2019","journal-title":"Physiol. Rev."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"37235","DOI":"10.1074\/jbc.M205932200","article-title":"High-affinity activators of cystic fibrosis transmembrane conductance regulator (CFTR) chloride conductance identified by high-throughput screening","volume":"277","author":"Ma","year":"2002","journal-title":"J. Biol. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"19723","DOI":"10.1074\/jbc.M101892200","article-title":"Novel CFTR chloride channel activators identified by screening of combinatorial libraries based on flavone and benzoquinolizinium lead compounds","volume":"276","author":"Galietta","year":"2001","journal-title":"J. Biol. Chem."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1089\/jop.2019.0087","article-title":"Nanomolar Potency Aminophenyltriazine CFTR Activator Reverses Corneal Epithelial Injury in a Mouse Model of Dry Eye","volume":"36","author":"Chen","year":"2020","journal-title":"J. Ocul. Pharmacol. Ther."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2401","DOI":"10.1021\/acs.jmedchem.6b01759","article-title":"High-Potency Phenylquinoxalinone Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Activators","volume":"60","author":"Son","year":"2017","journal-title":"J. Med. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1124\/mol.113.086348","article-title":"Novel amino-carbonitrile-pyrazole identified in a small molecule screen activates wild-type and DeltaF508 cystic fibrosis transmembrane conductance regulator in the absence of a cAMP agonist","volume":"84","author":"Namkung","year":"2013","journal-title":"Mol. Pharmacol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"4404","DOI":"10.1073\/pnas.1215982110","article-title":"Vx-770 potentiates CFTR function by promoting decoupling between the gating cycle and ATP hydrolysis cycle","volume":"110","author":"Jih","year":"2013","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3990","DOI":"10.1111\/bph.14475","article-title":"Potentiation of the cystic fibrosis transmembrane conductance regulator by VX-770 involves stabilization of the pre-hydrolytic, O(1) state","volume":"175","author":"Langron","year":"2018","journal-title":"Br. J. Pharmacol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"911","DOI":"10.1016\/j.cell.2010.11.029","article-title":"Loss of anion transport without increased sodium absorption characterizes newborn porcine cystic fibrosis airway epithelia","volume":"143","author":"Chen","year":"2010","journal-title":"Cell"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"e14603","DOI":"10.14814\/phy2.14603","article-title":"Effect of apical chloride concentration on the measurement of responses to CFTR modulation in airway epithelia cultured from nasal brushings","volume":"8","author":"Bratcher","year":"2020","journal-title":"Physiol. Rep."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.bbamem.2004.07.006","article-title":"Activation of human IK and SK Ca2+-activated K+ channels by NS309 (6,7-dichloro-1H-indole-2,3-dione 3-oxime)","volume":"1665","author":"Strobaek","year":"2004","journal-title":"Biochim. Biophys. Acta"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"10260","DOI":"10.1073\/pnas.1106695108","article-title":"Human cystic fibrosis airway epithelia have reduced Cl- conductance but not increased Na+ conductance","volume":"108","author":"Itani","year":"2011","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Nick, H.J., Zeitlin, P.L., Yadav, S., and Bratcher, P.E. (2021). Measurements of spontaneous CFTR-mediated ion transport without acute channel activation in airway epithelial cultures after modulator exposure. Sci. Rep., 11.","DOI":"10.1038\/s41598-021-02044-1"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"28401","DOI":"10.1074\/jbc.M800516200","article-title":"Regulation of CFTR trafficking by its R domain","volume":"283","author":"Lewarchik","year":"2008","journal-title":"J. Biol. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"C272","DOI":"10.1152\/ajpcell.1994.267.1.C272","article-title":"Heterotrimeric G proteins, vesicle trafficking, and CFTR Cl- channels","volume":"267","author":"Schwiebert","year":"1994","journal-title":"Am. J. Physiol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"C866","DOI":"10.1152\/ajpcell.00404.2009","article-title":"Influence of cell background on pharmacological rescue of mutant CFTR","volume":"298","author":"Pedemonte","year":"2010","journal-title":"Am. J. Physiol. Cell Physiol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Silva, I.A.L., Laselva, O., and Lopes-Pacheco, M. (2022). Advances in Preclinical In Vitro Models for the Translation of Precision Medicine for Cystic Fibrosis. J. Pers. Med., 12.","DOI":"10.3390\/jpm12081321"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"6802","DOI":"10.1073\/pnas.85.18.6802","article-title":"Enhancement of cAMP levels and of protein kinase activity by tumor necrosis factor and interleukin 1 in human fibroblasts: Role in the induction of interleukin 6","volume":"85","author":"Zhang","year":"1988","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"6668","DOI":"10.1038\/s41467-024-50641-1","article-title":"Allosteric inhibition of CFTR gating by CFTRinh-172 binding in the pore","volume":"15","author":"Gao","year":"2024","journal-title":"Nat. Commun."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Cui, G., Stauffer, B.B., Imhoff, B.R., Rab, A., Hong, J.S., Sorscher, E.J., and McCarty, N.A. (2019). VX-770-mediated potentiation of numerous human CFTR disease mutants is influenced by phosphorylation level. Sci. Rep., 9.","DOI":"10.1038\/s41598-019-49921-4"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"van der Horst, J., Greenwood, I.A., and Jepps, T.A. (2020). Cyclic AMP-Dependent Regulation of Kv7 Voltage-Gated Potassium Channels. Front. Physiol., 11.","DOI":"10.3389\/fphys.2020.00727"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Shaughnessy, C.A., Zeitlin, P.L., and Bratcher, P.E. (2021). Elexacaftor is a CFTR potentiator and acts synergistically with ivacaftor during acute and chronic treatment. Sci. Rep., 11.","DOI":"10.1038\/s41598-021-99184-1"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2485","DOI":"10.1038\/s41467-020-16239-z","article-title":"Dissecting the cellular specificity of smoking effects and reconstructing lineages in the human airway epithelium","volume":"11","author":"Goldfarbmuren","year":"2020","journal-title":"Nat. Commun."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"e121159","DOI":"10.1172\/jci.insight.121159","article-title":"Residual function of cystic fibrosis mutants predicts response to small molecule CFTR modulators","volume":"3","author":"Han","year":"2018","journal-title":"JCI Insight"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/2\/471\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,8]],"date-time":"2025-10-08T10:24:59Z","timestamp":1759919099000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/2\/471"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,1,8]]},"references-count":40,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2025,1]]}},"alternative-id":["ijms26020471"],"URL":"https:\/\/doi.org\/10.3390\/ijms26020471","relation":{},"ISSN":["1422-0067"],"issn-type":[{"type":"electronic","value":"1422-0067"}],"subject":[],"published":{"date-parts":[[2025,1,8]]}}}