Autocrine extracellular purinergic signaling in epithelial cells derived from polycystic kidneys.
ATP and its metabolites are potent autocrine agonists that act extracellularly within tissues to affect epithelial function. In polycystic kidneys, renal tubules become dilated and/or encapsulated as cysts, creating abnormal microenvironments for autocrine signaling. Previously, our laboratory has shown that high-nanomolar to micromolar quantities of ATP are released from cell monolayers in vitro and detectable in cyst fluids from microdissected human autosomal dominant polycystic kidney (ADPKD) cysts. Here, we show enhanced ATP release from autosomal recessive polycystic kidney (ARPKD) and ADPKD epithelial cell models. RT-PCR and immunoblotting for P2Y G protein-coupled receptors and P2X purinergic receptor channels show expression of mRNA and/or protein for multiple subtypes from both families. Assays of cytosolic Ca(2+) concentration and secretory Cl(-) transport show P2Y and P2X purinergic receptor-mediated stimulation of Cl(-) secretion via cytosolic Ca(2+)-dependent signaling. Therefore, we hypothesize that autocrine purinergic signaling may augment detrimentally cyst volume expansion in ADPKD or tubule dilation in ARPKD, accelerating disease progression.
Schwiebert
Erik M
EM
Department of Physiology and Biophysics, University of Alabama at Birmingham, 35294, USA. eschwiebert@physiology.uab.edu
Wallace
Darren P
DP
Braunstein
Gavin M
GM
King
Sandi R
SR
Peti-Peterdi
Janos
J
Hanaoka
Kazushige
K
Guggino
William B
WB
Guay-Woodford
Lisa M
LM
Bell
P Darwin
PD
Sullivan
Lawrence P
LP
Grantham
Jared J
JJ
Taylor
Amanda L
AL
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D019898:Autocrine Communication / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004847:Epithelial Cells / Q000502:physiology*; D005110:Extracellular Space / Q000502:physiology*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D008163:Luminescent Measurements; D051379:Mice; D007690:Polycystic Kidney Diseases / Q000473:pathology*; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002712:Chlorides; D018076:DNA, Complementary; D005456:Fluorescent Dyes; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D002118:Calcium; D016257:Fura-2