ABCMdb

PMID: 9950763

Clancy JP, Ruiz FE, Sorscher EJ
Adenosine and its nucleotides activate wild-type and R117H CFTR through an A2B receptor-coupled pathway.
Am J Physiol. 1999 Feb;276(2 Pt 1):C361-9., [PubMed]

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No. Mutations Sentence Comment

6 ABCC7 p.Arg117His It is published 12 times aAJP - Cell Physiology Adenosine and its nucleotides activate wild-type and R117H CFTR through an A2B receptor-coupled pathway JOHN P. CLANCY,1,2 FADEL E. RUIZ,1 AND ERIC J. SORSCHER2,3 Departments of 1Pediatrics and 3Medicine and 2Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005 Clancy, John P., Fadel E. Ruiz, and Eric J. Sorscher. Login to comment 7 ABCC7 p.Arg117His Adenosine and its nucleotides activate wild-type and R117H CFTR through an A2B receptor-coupled pathway. Login to comment 15 ABCC7 p.Arg117His We also present data showing that this pathway can activate clinically significant mutant CFTR molecules such as R117H. Login to comment 32 ABCC7 p.Arg117His We also show that the same receptor is present in human airway epithelial cells and provide the first example of activation of a clini- 0363-6143/99 $5.00 Copyright ௠ 1999 the American Physiological Society C361 cally important CFTR mutation (R117H) through this receptor-coupled pathway. Login to comment 37 ABCC7 p.Arg117His ABCC7 p.Arg117His After vaccinia infection, wtCFTR or R117H CFTR under control of the T7 promoter in the pTM-1 vector was introduced into cells in complex with 1,2-dioleoyl-3-trimethylammonium-propane/1,2- dioleoyl-sn-glycero-3-phosphoethanolamine (DOTAP/DOPE; 20 µg DOTAP/DOPE and 5 µg pTM-1 CFTR per 5 ϫ 105 cells) for 4 h. wtCFTR in the pTM-1 vector was the generous gift of Dr. S. Cheng (Genzyme, Cambridge, MA); R117H CFTR in the pTM-1vectorwasthegenerousgiftofDr.MichaelWelsh(Howard Hughes Medical Institute, University of Iowa, Iowa City, IA). Login to comment 100 ABCC7 p.Arg117His CA2B AR-COUPLED ACTIVATION OF WILD-TYPE AND R117H CFTR meability in the COS-7 and HeLa cell lines following transient expression. Login to comment 166 ABCC7 p.Arg117His CA2B AR-COUPLED ACTIVATION OF WILD-TYPE AND R117H CFTR ity influences ADO nucleotide-activated Cl-secretion by metabolizing ADO phosphates to ADO (37, 38, 40, 41). Login to comment 178 ABCC7 p.Arg117His We chose to study the R117H CFTR, which is known to localize to the cell surface and maintain normal PKA-dependent activation but which has reduced single-channel Cl-conductance (34, 43). Login to comment 179 ABCC7 p.Arg117His Figure 9 compares 10 µM ADO- and 10 µM forskolin-stimulated halide permeability in COS-7 cells expressing R117H CFTR, indicating similar strong responses. Login to comment 181 ABCC7 p.Arg117His Furthermore, activation of R117H CFTR byADO is qualitatively similar to that obtained by pharmacologic stimulation of adenyl cyclase. Login to comment 232 ABCC7 p.Arg117His R117H CFTR is activated by ADO (10 µM) or forskolin (10 µM). Login to comment 233 ABCC7 p.Arg117His Expression of R117H CFTR was performed as described (see METHODS). Login to comment 235 ABCC7 p.Arg117His CA2B AR-COUPLED ACTIVATION OF WILD-TYPE AND R117H CFTR lowing conversion to ADO by surface-localized CD73 (ecto-5Ј-nucleotidase) in T84 cells (25, 37, 38). Login to comment 238 ABCC7 p.Arg117His A2B receptor stimulation of COS-7 cells expressing either wtCFTR or R117H CFTR indicates that this G protein-coupled receptor can effectively activate CFTR-dependent halide transport (Fig. 9). Login to comment 239 ABCC7 p.Arg117His The R117H CFTR represents a class IV CFTR mutation, characterized by intact protein production, maturation, surface localization, and regulation but defective single-channel Cl- conduction (34, 43). Login to comment 241 ABCC7 p.Arg117His The phenotype of patients possessing the R117H mutation is unusual. Login to comment 243 ABCC7 p.Arg117His It has therefore been suggested that the R117H mutation may rest at the boundary of required CFTR function in two organ systems, providing adequate function to protect the exocrine pancreas but failing to provide the necessary function in the lungs to protect the airways from the pulmonary manifestations of cystic fibrosis. Login to comment 244 ABCC7 p.Arg117His ABCC7 p.Arg117His Although Cl-transport in cells expressing the common ⌬F508 CFTR trafficking mutant may not be expected to be stimulated by A2B AR activation, our studies raise the possibility that the function of R117H CFTR and possibly other class IV surface-localized CFTR mutations might be augmented through pharmacologic activation of A2B AR. Login to comment 246 ABCC7 p.Arg117His ABCC7 p.Arg117His In summary, these experiments are the first to describe 1) AR-coupled CFTR activation by ADO and adenosine mono-, di-, and triphosphates in a cell line devoid of endogenous competing Cl-transport pathways, 2) A2B AR regulation of CFTR-dependent halide transport, 3) A2B AR protein in COS-7 and native human bronchial epithelia, and 4) A2B receptor activation of R117H CFTR. Login to comment 247 ABCC7 p.Arg117His The findings help clarify the positive regulatory effects that ADO and its nucleotides can confer to wtCFTR and R117H CFTR through the A2B AR. Login to comment 251 ABCC7 p.Ala455Glu ABCC7 p.Gly1349Asp For example, additional experiments in COS-7 cells have recently allowed us to identify two other surface-localized CFTR mutants (A455E and G1349D) that can functionally couple to A2B AR activation (11). Login to comment