Gendron Fernand-Pierre, Chalimoniuk Malgorzata, Strosznajder Joanna, Shen Siming, González Fernando A, Weisman Gary A, Sun Grace Y
Department of Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65212, USA.
J Neurochem. 2003 Oct;87(2):344-52. doi: 10.1046/j.1471-4159.2003.01995.x.
Under normal and pathological conditions, brain cells release nucleotides that regulate a wide range of cellular responses due to activation of P2 nucleotide receptors. In this study, the effect of extracellular nucleotides on IFN gamma-induced NO release in murine BV-2 microglial cells was investigated. BV-2 cells expressed mRNA for metabotropic P2Y and ionotropic P2X receptors. Among the P2 receptor agonists tested, ATP, ADP, 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP), and 2-methylthio-ATP (2-MeSATP), but not UTP, enhanced IFN gamma-induced iNOS expression and NO production, suggesting that the uridine nucleotide receptors P2Y2 and P2Y6 are not involved in this response. U0126, an antagonist for MEK1/2, a kinase that phosphorylates the extracellular signal-regulated kinases ERK1/2, decreased IFN gamma-induced NO production. BzATP, a potent P2X7 receptor agonist, was more effective than ATP, ADP, or 2-MeSATP at enhancing IFN gamma-induced ERK1/2 phosphorylation. Consistent with activation of the P2X7 receptor, periodate-oxidized ATP, a P2X7 receptor antagonist, and suramin, a non-specific P2 receptor antagonist, inhibited the effect of ATP or BzATP on IFN gamma-induced NO production, whereas pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), an antagonist of several P2X receptor subtypes, was ineffective. These results suggest that activation of P2X7 receptors may contribute to inflammatory responses in microglial cells seen in neurodegenerative diseases.
在正常和病理条件下，脑细胞会释放核苷酸，这些核苷酸由于P2核苷酸受体的激活而调节多种细胞反应。在本研究中，研究了细胞外核苷酸对小鼠BV-2小胶质细胞中IFNγ诱导的NO释放的影响。BV-2细胞表达代谢型P2Y和离子型P2X受体的mRNA。在所测试的P2受体激动剂中，ATP、ADP、2'，3'-O-(4-苯甲酰苯甲酰)-ATP（BzATP）和2-甲硫基-ATP（2-MeSATP），但不是UTP，增强了IFNγ诱导的iNOS表达和NO产生，这表明尿苷核苷酸受体P2Y2和P2Y6不参与此反应。U0126是MEK1/2的拮抗剂，MEK1/2是一种使细胞外信号调节激酶ERK1/2磷酸化的激酶，它降低了IFNγ诱导的NO产生。BzATP是一种有效的P2X7受体激动剂，在增强IFNγ诱导的ERK1/2磷酸化方面比ATP、ADP或2-MeSATP更有效。与P2X7受体的激活一致，高碘酸盐氧化的ATP（一种P2X7受体拮抗剂）和苏拉明（一种非特异性P2受体拮抗剂）抑制了ATP或BzATP对IFNγ诱导的NO产生的作用，而几种P2X受体亚型的拮抗剂吡哆醛-磷酸-6-偶氮苯基-2'，4'-二磺酸（PPADS）则无效。这些结果表明，P2X7受体的激活可能有助于神经退行性疾病中所见的小胶质细胞炎症反应。
