title: Natural compounds with P2X7 receptor-modulating properties.
abstract: The adenosine 5'-triphosphate (ATP)-gated P2X7 receptor is a membrane-bound, non-selective cation channel, expressed in a variety of cell types. The P2X7 senses high extracellular ATP concentrations and seems to be implicated in a wide range of cellular functions as well as pathophysiological processes, including immune responses and inflammation, release of gliotransmitters and cytokines, cancer cell growth or development of neurodegenerative diseases. In the present study, we identified natural compounds and analogues that can block or sensitize the ATP (1 mM)-induced Ca(2+) response using a HEK293 cell line stably expressing human P2X7 and fluorometric imaging plate reader technology. For instance, teniposide potently blocked the human P2X7 at sub-miromolar concentrations, but not human P2X4 or rat P2X2. A marked block of ATP-induced Ca(2+) entry and Yo-Pro-1 uptake was also observed in human A375 melanoma cells and mouse microglial cells, both expressing P2X7. On the other hand, agelasine (AGL) and garcinolic acid (GA) facilitated the P2X7 response to ATP in all three cell populations. GA also enhanced the YO-PRO-1 uptake, whereas AGL did not affect the ATP-stimulated intracellular accumulation of this dye. According to the pathophysiological role of P2X7 in various diseases, selective modulators may have potential for further development, e.g. as neuroprotective or antineoplastic drugs.
authors.affiliation: Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Haertelstr. 16-18, 04107, Leipzig, Germany, fisw@medizin.uni-leipzig.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fischer
authors.forename: Nicole
authors.initials: N
authors.lastname: Urban
authors.forename: Kerstin
authors.initials: K
authors.lastname: Immig
authors.forename: Heike
authors.initials: H
authors.lastname: Franke
authors.forename: Michael
authors.initials: M
authors.lastname: Schaefer
mesh_terms: D000818:Animals; D004353:Drug Evaluation, Preclinical; D005455:Fluorescent Antibody Technique; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D018613:Microscopy, Confocal; D058911:Purinergic P2X Receptor Agonists / Q000494:pharmacology*; D058920:Purinergic P2X Receptor Antagonists / Q000494:pharmacology*; D051381:Rats; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism*
chemical_list: D058911:Purinergic P2X Receptor Agonists; D058920:Purinergic P2X Receptor Antagonists; D058486:Receptors, Purinergic P2X7