P2X(7) receptors are expressed during mouse nephrogenesis and in collecting duct cysts of the cpk/cpk mouse.
BACKGROUND
Purinergic receptors are cell-surface molecules that bind extracellular nucleotides, notably ATP. The P2X family includes seven nonselective ion channels with one member, P2X(7), implicated in cytolytic pore formation and cell death.


METHODS
We sought P2X(7) expression in mouse nephrogenesis and cpk/cpk renal cyst growth, conditions in which both proliferation and apoptosis are prominent.


RESULTS
P2X(7) immunolocalized to condensed metanephric mesenchyme: both proliferation and apoptosis were detected in this compartment, assessed by proliferating cell nuclear antigen expression and propidium iodide-stained pyknotic nuclei respectively. Later in nephrogenesis, P2X(7) was detected in collecting ducts, a pattern persisting to maturity. A mesenchymal to epithelial shift of P2X(7) expression was also documented in ureter development. In cpk/cpk kidneys, P2X(7)-expressing collecting duct cysts dominated histology from two weeks until four weeks after birth, when animals die from uremia. In polycystic kidneys pyknotic nuclei were rarely identified in P2X(7)-expressing epithelia, but were detected between cysts, consistent with a non-apoptotic role for P2X(7) in cyst enlargement.


CONCLUSIONS
P2X(7) is expressed during normal nephrogenesis and in a model of congenital polycystic kidney disease. Further experiments are necessary to define possible functions of P2X(7) in these settings.
Hillman
Katherine A
KA
Centre for Nephrology, Institute of Urology and Nephrology, Middlesex Hospital, University College London, London, UK. k.Hillman@ucl.ac.uk
Johnson
Tanya M
TM
Winyard
Paul J D
PJ
Burnstock
Geoffrey
G
Unwin
Robert J
RJ
Woolf
Adrian S
AS
D000375:Aging; D000818:Animals; D015153:Blotting, Western; D007150:Immunohistochemistry; D007668:Kidney / Q000196:embryology* / Q000254:growth & development* / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000254:growth & development / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D018613:Microscopy, Confocal; D007690:Polycystic Kidney Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018048:Receptors, Purinergic P2 / Q000276:immunology / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7
C546469:P2rx7 protein, mouse; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7