Purinergic regulation of CFTR and Ca²⁺ -activated C^l- channels and K⁺ channels in human pancreatic duct epithelium

TY - JOUR

T1 - Purinergic regulation of CFTR and Ca2+ -activated Cl- channels and K+ channels in human pancreatic duct epithelium

AU - Wang, Jing

AU - Haanes, Kristian A

AU - Novak, Ivana

PY - 2013/4/1

Y1 - 2013/4/1

N2 - Purinergic agonists have been considered for the treatment of respiratory epithelia in cystic fibrosis (CF) patients. The pancreas, one of the most seriously affected organs in CF, expresses various purinergic receptors. Studies on the rodent pancreas show that purinergic signaling regulates pancreatic secretion. In the present study we aim to identify Cl- and K+ channels in human pancreatic ducts and their regulation by purinergic receptors. Human pancreatic duct epithelia formed by Capan-1 or CFPAC-1 cells were studied in open-circuit Ussing chambers. In Capan-1 cells, ATP/UTP effects were dependent on intracellular Ca2+. Apically applied ATP/UTP stimulated CF transmembrane conductance regulator (CFTR) and Ca2+-activated Cl- (CaCC) channels, which were inhibited by CFTRinh-172 and niflumic acid, respectively. The basolaterally applied ATP stimulated CFTR. In CFPAC-1 cells, which have mutated CFTR, basolateral ATP and UTP had negligible effects. In addition to Cl- transport in Capan-1 cells, the effects of 5, 6-dichloro-1-ethyl-1, 3-dihydro-2H-benzimidazol-2-one (DC-EBIO) and clotrimazole indicated functional expression of the intermediate conductance K+ channels (IK, KCa3.1). The apical effects of ATP/UTP were greatly potentiated by the IK channel opener DC-EBIO. Determination of RNA and protein levels revealed that Capan-1 cells have high expression of TMEM16A (ANO1), a likely CaCC candidate. We conclude that in human pancreatic duct cells ATP/UTP regulates via purinergic receptors both Cl- channels (TMEM16A/ANO1 and CFTR) and K+ channels (IK). The K+ channels provide the driving force for Cl--channel-dependent secretion, and luminal ATP provided locally or secreted from acini may potentiate secretory processes. Future strategies in augmenting pancreatic duct function should consider sidedness of purinergic signaling and the essential role of K+ channels.

AB - Purinergic agonists have been considered for the treatment of respiratory epithelia in cystic fibrosis (CF) patients. The pancreas, one of the most seriously affected organs in CF, expresses various purinergic receptors. Studies on the rodent pancreas show that purinergic signaling regulates pancreatic secretion. In the present study we aim to identify Cl- and K+ channels in human pancreatic ducts and their regulation by purinergic receptors. Human pancreatic duct epithelia formed by Capan-1 or CFPAC-1 cells were studied in open-circuit Ussing chambers. In Capan-1 cells, ATP/UTP effects were dependent on intracellular Ca2+. Apically applied ATP/UTP stimulated CF transmembrane conductance regulator (CFTR) and Ca2+-activated Cl- (CaCC) channels, which were inhibited by CFTRinh-172 and niflumic acid, respectively. The basolaterally applied ATP stimulated CFTR. In CFPAC-1 cells, which have mutated CFTR, basolateral ATP and UTP had negligible effects. In addition to Cl- transport in Capan-1 cells, the effects of 5, 6-dichloro-1-ethyl-1, 3-dihydro-2H-benzimidazol-2-one (DC-EBIO) and clotrimazole indicated functional expression of the intermediate conductance K+ channels (IK, KCa3.1). The apical effects of ATP/UTP were greatly potentiated by the IK channel opener DC-EBIO. Determination of RNA and protein levels revealed that Capan-1 cells have high expression of TMEM16A (ANO1), a likely CaCC candidate. We conclude that in human pancreatic duct cells ATP/UTP regulates via purinergic receptors both Cl- channels (TMEM16A/ANO1 and CFTR) and K+ channels (IK). The K+ channels provide the driving force for Cl--channel-dependent secretion, and luminal ATP provided locally or secreted from acini may potentiate secretory processes. Future strategies in augmenting pancreatic duct function should consider sidedness of purinergic signaling and the essential role of K+ channels.

KW - Adenosine Triphosphate

KW - Calcium

KW - Cell Line

KW - Chloride Channels

KW - Cystic Fibrosis Transmembrane Conductance Regulator

KW - Epithelial Cells

KW - Gene Expression Regulation

KW - Humans

KW - Pancreatic Ducts

KW - Potassium Channels, Calcium-Activated

KW - Receptors, Purinergic P2X

KW - Receptors, Purinergic P2Y

KW - Uridine Triphosphate

U2 - 10.1152/ajpcell.00196.2012

DO - 10.1152/ajpcell.00196.2012

M3 - Journal article

C2 - 23364268

SN - 0363-6143

VL - 304

SP - C673-84

JO - American Journal of Physiology: Cell Physiology

JF - American Journal of Physiology: Cell Physiology

IS - 7

ER -