Identification Of Alternatively Spliced MRNAs For Soluble Adenylyl Cyclase In Normal Airway Epithelial Cells

CFTR channels conduct HCO3− in addition to Cl− in airway epithelial cells. A defective HCO3−-transporting function of CFTR may underlie the pathogenesis of cystic fibrosis. In the present study, we have investigated whether a HCO3−-sensitive soluble adenylyl cyclase (sAC) is functionally coupled with CFTR and thus forms an autoregulatory mechanism for HCO3− transport in human airway epithelial Calu-3 cells. A reverse transcriptase-polymerase chain reaction showed that transcripts of both full-length and truncated sACs are present in Calu-3 cells. Truncated sAC protein is the predominant, if not the only, isoform expressed in Calu-3 cells. HCO3− stimulated a modest increase in cAMP production, and the increase was sensitive to 2-hydroxyestradiol (2-HE), a sAC inhibitor, but not to SQ22,536, a blocker of conventional transmembrane adenylyl cyclases. These results suggest that sAC is functional in Calu-3 cells. Adding 25 mM HCO3− to the bath stimulated CFTR-mediated whole cell currents in the absence, but not in the presence, of 2-HE. In cell-attached membrane patches, 25 or 50 mM HCO3− in the bath markedly increased the product of channel number and open probability of CFTR, and this activation was attenuated by 2-HE. These findings demonstrate that sAC signaling pathway is involved in the regulation of CFTR function in human airway epithelium and thereby provides a link between the level of intracellular HCO3−/CO2 and the modulation of HCO3−-conductive CFTR function by cAMP/PKA.

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Regulation of CFTR channels by bicarbonate-sensitive soluble adenylyl cyclase in human airway epithelial cells

10.14711/thesis-b864002 ◽

2005 ◽

Author(s):

Chak Sum Lam

Keyword(s):

Epithelial Cells ◽

Adenylyl Cyclase ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Soluble Adenylyl Cyclase ◽

Human Airway ◽

Human Airway Epithelial Cells

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Expression and function of the beta-adrenergic receptor coupled-adenylyl cyclase system on human airway epithelial cells.

American Journal of Respiratory and Critical Care Medicine ◽

10.1164/ajrccm.152.6.8520736 ◽

1995 ◽

Vol 152 (6) ◽

pp. 1774-1783 ◽

Cited By ~ 17

Author(s):

S G Kelsen ◽

N C Higgins ◽

S Zhou ◽

I A Mardini ◽

J L Benovic

Keyword(s):

Epithelial Cells ◽

Adenylyl Cyclase ◽

Adrenergic Receptor ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Beta Adrenergic Receptor ◽

Beta Adrenergic ◽

Human Airway ◽

Adenylyl Cyclase System ◽

And Function

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Conditionally Reprogrammed Human Normal Airway Epithelial Cells at ALI: A Physiological Model for Emerging Viruses

Virologica Sinica ◽

10.1007/s12250-020-00244-z ◽

2020 ◽

Vol 35 (3) ◽

pp. 280-289

Author(s):

Xuefeng Liu ◽

Yuntao Wu ◽

Lijun Rong

Keyword(s):

Epithelial Cells ◽

Physiological Model ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Emerging Viruses ◽

Normal Airway

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CFTR-Adenylyl Cyclase I Association Responsible for UTP Activation of CFTR in Well-Differentiated Primary Human Bronchial Cell Cultures

Molecular Biology of the Cell ◽

10.1091/mbc.e09-12-1004 ◽

2010 ◽

Vol 21 (15) ◽

pp. 2639-2648 ◽

Cited By ~ 47

Author(s):

Wan Namkung ◽

Walter E. Finkbeiner ◽

A. S. Verkman

Keyword(s):

Epithelial Cells ◽

Adenylyl Cyclase ◽

Cell Cultures ◽

Secretory Pathway ◽

Primary Cultures ◽

Chloride Secretion ◽

Airway Epithelial Cells ◽

Chloride Current ◽

Airway Epithelial ◽

Camp Elevation

Chloride secretion by airway epithelial cells is defective in cystic fibrosis (CF). The conventional paradigm is that CFTR is activated through cAMP and protein kinase A (PKA), whereas the Ca2+-activated chloride channel (CaCC) is activated by Ca2+ agonists like UTP. We found that most chloride current elicited by Ca2+ agonists in primary cultures of human bronchial epithelial cells is mediated by CFTR by a mechanism involving Ca2+ activation of adenylyl cyclase I (AC1) and cAMP/PKA signaling. Use of selective inhibitors showed that Ca2+ agonists produced more chloride secretion from CFTR than from CaCC. CFTR-dependent chloride secretion was reduced by PKA inhibition and was absent in CF cell cultures. Ca2+ agonists produced cAMP elevation, which was blocked by adenylyl cyclase inhibition. AC1, a Ca2+/calmodulin-stimulated adenylyl cyclase, colocalized with CFTR in the cell apical membrane. RNAi knockdown of AC1 selectively reduced UTP-induced cAMP elevation and chloride secretion. These results, together with correlations between cAMP and chloride current, suggest that compartmentalized AC1–CFTR association is responsible for Ca2+/cAMP cross-talk. We further conclude that CFTR is the principal chloride secretory pathway in non-CF airways for both cAMP and Ca2+ agonists, providing a novel mechanism to link CFTR dysfunction to CF lung disease.

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IL-1 beta alters beta-adrenergic receptor adenylyl cyclase system function in human airway epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1997.273.3.l694 ◽

1997 ◽

Vol 273 (3) ◽

pp. L694-L700 ◽

Cited By ~ 5

Author(s):

S. G. Kelsen ◽

O. Anakwe ◽

M. O. Aksoy ◽

P. J. Reddy ◽

N. Dhanasekaran

Keyword(s):

Epithelial Cells ◽

Adenylyl Cyclase ◽

Pertussis Toxin ◽

Adrenergic Receptor ◽

Airway Epithelial Cells ◽

System Function ◽

Airway Epithelial ◽

Camp Production ◽

Gtp Binding Protein ◽

Gtp Binding

Inflammatory cells release a variety of cytokines, including interleukin (IL)-1 beta, into the airway in asthma. This study examined the effects of human IL-1 beta on the function of the beta-adrenergic receptor (beta AR)-adenylyl cyclase (AC) system in BEAS-2B cells, a human airway epithelial cell line. IL-1 beta markedly increased beta AR density (Bmax; P < 0.001) primarily by increasing the percentage of the beta 2AR subtype (from 67 to 91%; P < 0.001). Bmax increased monotonically over time in response to 200 pM IL-1 beta and was approximately 2.5-fold greater than control cells between 36 and 42 h. In contrast, the concentration response of Bmax to IL-1 beta given for 18 h was biphasic. Bmax increased with IL-1 beta concentrations from 2 to 200 pM, but, at > 200 pM, it decreased progressively toward control values. IL-1 beta-induced increases in Bmax with IL-1 beta were associated with approximately threefold increases in beta 2 AR mRNA and were blocked by the protein synthesis inhibitor cycloheximide. Despite the marked increase in Bmax, however, IL-1 beta depressed adenosine 3',5'-cyclic monophosphate (cAMP) responses to isoproterenol and forskolin, a direct activator of AC (P < 0.001 by analysis of variance for both). The inhibitory effect of IL-1 beta on cAMP production appeared to be explained by increases in the activity of an inhibitory GTP binding protein because IL-1 beta treatment increased the activity of a pertussis toxin ADP-ribosylated Gi alpha protein by approximately 2.5-fold; and pretreatment of intact cells with pertussis toxin inhibited the effect of IL-1 beta on cAMP production. These data indicate that IL-1 beta-mediated changes in the beta AR-AC system function in airway epithelial cells are complex and involve expression of receptor protein, GTP binding protein, and possibly AC itself. Increases in IL-1 beta may contribute to abnormalities in airway function in subjects with asthma.

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