title: Involvement of P2X4 receptor in P2X7 receptor-dependent cell death of mouse macrophages.
abstract: Interaction of P2X7 receptor with P2X4 receptor has recently been suggested, but it remains unclear whether P2X4 receptor is involved in P2X7 receptor-mediated events, such as cell death of macrophages induced by high concentrations of extracellular ATP. Here, we present evidence that P2X4 receptor does play a role in P2X7 receptor-dependent cell death. Treatment of mouse macrophage RAW264.7 cells with 1mM ATP induced Ca(2+) influx, non-selective large pore formation, activation of extracellular signal-regulated protein kinase (ERK) 1/2 and p38 mitogen-activated protein kinase (MAPK), and cell death via activation of P2X7 receptor. P2X4-knockdown cells, established by transfecting RAW264.7 cells with two short hairpin RNAs (shRNAs) targeting P2X4 receptor, showed a decrease of the initial peak of intracellular Ca(2+) after treatment with ATP, though pore formation and the P2X7-mediated activation of ERK1/2 and p38 MAPK were not affected. Intriguingly, P2X4 knockdown resulted in significant suppression of cell death induced by ATP or P2X7 agonist BzATP. In conclusion, our results suggest that P2X4 receptor is involved in P2X7 receptor-mediated cell death, but not pore formation or MAPK signaling.
authors.affiliation: Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi Chiba 278-8510, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kawano
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Tsukimoto
authors.forename: Taisei
authors.initials: T
authors.lastname: Noguchi
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hotta
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Harada
authors.forename: Takato
authors.initials: T
authors.lastname: Takenouchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitani
authors.forename: Shuji
authors.initials: S
authors.lastname: Kojima
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D055785:Gene Knockdown Techniques; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D058911:Purinergic P2X Receptor Agonists / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D058848:Receptors, Purinergic P2X4 / Q000235:genetics / Q000502:physiology*; D058486:Receptors, Purinergic P2X7 / Q000502:physiology*
chemical_list: D058911:Purinergic P2X Receptor Agonists; D034741:RNA, Small Interfering; D058848:Receptors, Purinergic P2X4; D058486:Receptors, Purinergic P2X7; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D002118:Calcium