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Acta Physiologica 2009; Volume 197, Supplement 675
Joint meeting of The Slovenian Physiological Society, The Austrian Physiological Society and The Federation of European Physiological Societies
11/12/2009-11/15/2009
Ljubljana, Slovenia
PURINERGIC SIGNALING IN THE PULMONARY NEUROEPITHELIAL BODY MICROENVIRONMENT UNRAVELED BY LIVE CELL IMAGING
Abstract number: L160
De Proost1,2 Ian, Pintelon1 Isabel, J Wilkinson2 William, Goethals1 Sofie, Brouns1 Inge, Van Nassauw1 Luc, Riccardi2 Daniela, Timmermans1 Jean-Pierre, J Kemp2 Paul, Adriaensen1 Dirk
1Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Groenenborgerlaan 171, BE-2020, Antwerp, Belgium
2Cardiff School of Biosciences, Museum Avenue, Cardiff CF10 3US, Wales, UK
Pulmonary neuroepithelial bodies (NEBs) occur in the airway epithelium as densely innervated groups of neuroendocrine cells that are largely shielded from the airway lumen by a specialized type of Clara cell, the so-called Clara-like cells. In ex vivo mouse lung slices, NEB cells respond with a rise in intracellular calcium ([Ca2+]i)upon membrane depolarisation with high K+, typically followed by a delayed [Ca2+]iincrease in the surrounding Clara-like cells, suggestive of an indirect activation. Aim of the present study was to explore the mechanism of this potential interaction between NEBs and Clara-like cells. We employed confocal live cell imaging microscopy and novel electrophysiological techniques in the ex vivo lung slice model and focused on a possible purinergic signalling pathway.
Quinacrine histochemistry indicated high amounts of vesicular ATP in NEB cells. Using a 'reporter-patching' method adapted to create a uniquely sensitive and selective biosensor for the direct detection of ATP release from NEBs ex vivo, we demonstrated quantal ATP release from NEBs following their depolarisation with high K+. Use of enhanced extracellular enzymatic ATP hydrolysis or the P2 receptor blocker suramin confirmed the central role of ATP in the paracrine interactions between NEBs and Clara-like cells. Combined calcium imaging, pharmacology and immunohistochemistry showed that ligand-binding to functional P2Y2 receptors underpins the activation of Clara-like cells.
Hence, NEB cells communicate with their cellular neighbours in the NEB microenvironment by releasing ATP, which rapidly evokes purinergic activation of surrounding Clara-like cells. Besides ATP acting on the P2X3 receptor expressing vagal sensory nerve terminals that we reported earlier between NEB cells, local paracrine purinergic signalling within this potential stem cell niche may be important to both normal airway function, airway epithelial regeneration after injury, and/or the pathogenesis of small cell lung carcinomas.
Support: FWO grand G.0081.08 (DA); UA grants NOI BOF 2003, GOA BOF 2007 (DA) and KP BOF 2006 (IB); BBSRC, BHF and MRC grants (PJK, DR).
To cite this abstract, please use the following information:
Acta Physiologica 2009; Volume 197, Supplement 675 :L160