Development of substituted benzo[c]quinolizinium compounds as novel activators of the cystic fibrosis chloride channel

Frédéric Becq, Yvette Mettey, Mike A. Gray, Luis J V Galietta, Robert L. Dormer, Marc Merten, Thierry Métayé, Valérie Chappe, Cécie Marvingt-Mounir, Olga Zegarra-Moran, Robert Tarran, Laurence Bulteau, Renaud Dérand, Malcome M C Pereira, Margaret A. McPherson, Christian Rogier, Michel Joffre, Barry E. Argent, Denis Sarrouilhe, Wafa KammouniCatherine Figarella, Bernard Verrier, Maurice Gola, Jean Michel Vierfond

Research output: Contribution to journalArticlepeer-review


Chloride channels play an important role in the physiology and pathophysiology of epithelia, but their pharmacology is still poorly developed. We have chemically synthesized a series of substituted benzo[c]quinolizinium (MPB) compounds. Among them, 6-hydroxy-7- chlorobenzo[c]quinolizinium (MPB-27) and 6-hydroxy-10- chlorobenzo[c]quinolizinium (MPB-07), which we show to be potent and selective activators of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. We examined the effect of MPB compounds on the activity of CFTR channels in a variety of established epithelial and nonepithelial cell systems. Using the iodide efflux technique, we show that MPB compounds activate CFTR chloride channels in Chinese hamster ovary (CHO) cells stably expressing CFTR but not in CHO cells lacking CFTR. Single and whole cell patch clamp recordings from CHO cells confirm that CFTR is the only channel activated by the drugs. Ussing chamber experiments reveal that the apical addition of MPB to human nasal epithelial cells produces a large increase of the short circuit current. This current can be totally inhibited by glibenclamide. Whole cell experiments performed on native respiratory cells isolated from wild type and CF null mice also show that MPB compounds specifically activate CFTR channels. The activation of CFTR by MPB compounds was glibenclamide-sensitive and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid-insensitive. In the human tracheal gland cell line MM39, MPB drugs activate CFTR channels and stimulate the secretion of the antibacterial secretory leukoproteinase inhibitor. In submandibular acinar cells, MPB compounds slightly stimulate CFTR-mediated submandibular mucin secretion without changing intracellular cAMP and ATP levels. Similarly, in CHO cells MPB compounds have no effect on the intracellular levels of cAMP and ATP or on the activity of various protein phosphatases (PP1, PP2A, PP2C, or alkaline phosphatase). Our results provide evidence that substituted benzo[c]quinolizinium compounds are a novel family of activators of CFTR and of CFTR-mediated protein secretion and therefore represent a new tool to study CFTR-mediated chloride and secretory functions in epithelial tissues.

Original languageEnglish
Pages (from-to)27415-27425
Number of pages11
JournalJournal of Biological Chemistry
Issue number39
Publication statusPublished - Sep 24 1999

ASJC Scopus subject areas

  • Biochemistry


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