title: Inhibitors of the 5-lipoxygenase arachidonic acid pathway induce ATP release and ATP-dependent organic cation transport in macrophages.
abstract: We have previously described that arachidonic acid (AA)-5-lipoxygenase (5-LO) metabolism inhibitors such as NDGA and MK886, inhibit cell death by apoptosis, but not by necrosis, induced by extracellular ATP (ATPe) binding to P2X7 receptors in macrophages. ATPe binding to P2X7 also induces large cationic and anionic organic molecules uptake in these cells, a process that involves at least two distinct transport mechanisms: one for cations and another for anions. Here we show that inhibitors of the AA-5-LO pathway do not inhibit P2X7 receptors, as judged by the maintenance of the ATPe-induced uptake of fluorescent anionic dyes. In addition, we describe two new transport phenomena induced by these inhibitors in macrophages: a cation-selective uptake of fluorescent dyes and the release of ATP. The cation uptake requires secreted ATPe, but, differently from the P2X7/ATPe-induced phenomena, it is also present in macrophages derived from mice deficient in the P2X7 gene. Inhibitors of phospholipase A2 and of the AA-cyclooxygenase pathway did not induce the cation uptake. The uptake of non-organic cations was investigated by measuring the free intracellular Ca(2+) concentration ([Ca(2+)]i) by Fura-2 fluorescence. NDGA, but not MK886, induced an increase in [Ca(2+)]i. Chelating Ca(2+) ions in the extracellular medium suppressed the intracellular Ca(2+) signal without interfering in the uptake of cationic dyes. We conclude that inhibitors of the AA-5-LO pathway do not block P2X7 receptors, trigger the release of ATP, and induce an ATP-dependent uptake of organic cations by a Ca(2+)- and P2X7-independent transport mechanism in macrophages.
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia de Pesquisa Translacional em Saúde e ambiente da Região Amazônica - INPeTAm.
authors.forename: Hercules Antônio
authors.initials: HA
authors.lastname: da Silva-Souza
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia de Pesquisa Translacional em Saúde e ambiente da Região Amazônica - INPeTAm.
authors.forename: Maria Nathalia de
authors.initials: MN
authors.lastname: Lira
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.
authors.forename: Helio Miranda
authors.initials: HM
authors.lastname: Costa-Junior
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.
authors.forename: Cristiane Monteiro
authors.initials: CM
authors.lastname: da Cruz
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.
authors.forename: Jorge Silvio Silva
authors.initials: JS
authors.lastname: Vasconcellos
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil.
authors.forename: Anderson Nogueira
authors.initials: AN
authors.lastname: Mendes
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia de Pesquisa Translacional em Saúde e ambiente da Região Amazônica - INPeTAm.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Pimenta-Reis
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia de Pesquisa Translacional em Saúde e ambiente da Região Amazônica - INPeTAm.
authors.forename: Cora Lilia
authors.initials: CL
authors.lastname: Alvarez
authors.affiliation: Departamento de Análises Clínicas Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903, Ribeirão Preto, SP, Brazil.
authors.forename: Lucia Helena
authors.initials: LH
authors.lastname: Faccioli
authors.affiliation: Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202 USA.
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: Serezani
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia de Pesquisa Translacional em Saúde e ambiente da Região Amazônica - INPeTAm.
authors.forename: Julieta
authors.initials: J
authors.lastname: Schachter
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia de Pesquisa Translacional em Saúde e ambiente da Região Amazônica - INPeTAm. Electronic address: pedromp@biof.ufrj.br.
authors.forename: Pedro Muanis
authors.initials: PM
authors.lastname: Persechini
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002412:Cations / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D054467:Phospholipases A2 / Q000378:metabolism; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism
chemical_list: D002412:Cations; D016859:Lipoxygenase Inhibitors; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; D001094:Arachidonate 5-Lipoxygenase; D054467:Phospholipases A2; D002118:Calcium
keywords: 5-lipoxygenase inhibitors; ATP; Cation transporters; Macrophage; P2X7 receptor