The antibiotic polymyxin B modulates P2X7 receptor function
The antibiotic polymyxin B modulates P2X7 receptor function
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DOI：
10.4049/jimmunol.173.7.4652
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发表时间：
2004-10-01
影响因子：
4.4
通讯作者：
Di Virgilio, F
中科院分区：
文献类型：
--
作者：
Ferrari, D;Pizzirani, C;Di Virgilio, F
天然多肽多粘菌素B（PMB）是一种结合并中和细菌内毒素（LPS）的强效抗生素，从而防止其在动物模型中LPS介导的内毒素休克中的毒性作用。我们研究了PMB对P2 X（7）R介导的HEK 293和K562细胞（转染P2 X（7）cDNA）以及小鼠和人巨噬细胞反应的影响。此外，鉴于P2 X（7）-定向激动剂在抗肿瘤治疗中的潜在开发，我们还研究了PMB对慢性淋巴细胞白血病患者B淋巴细胞的作用。在取决于给定细胞类型的最佳浓度下，PMB极大地增强了核苷酸介导的P2 X（7）刺激的效果。特别是，ATP介导的Ca 2+内流，质膜透化，和细胞毒性增强到一定程度，在PMB的存在下，细胞被杀死，否则无效的核苷酸浓度。与不可逆的P2 X阻断剂氧化型ATP（oATP）孵育可阻止ATP和PMB联合应用的协同效应，但与可逆拮抗剂1-（N，O-双（1，5-异喹啉磺酰基）-N-甲基-（L）-酪氨酰基）-4-苯基哌啶（KN-62）孵育则无此作用。缺乏P2 X的细胞（7）对PMB和ATP的联合刺激完全不敏感。此外，所用浓度的PMB对细胞活力没有不良影响。这些结果表明PMB是调节P2 X（7）R功能的有用工具，并表明在PMB存在下评估ATP刺激的免疫细胞应答时应小心，因为它们可能不仅仅受到污染LPS去除的影响。
The natural peptide polymyxin B (PMB) is a well-known and potent antibiotic that binds and neutralizes bacterial endotoxin (LPS), thus preventing its noxious effects among LPS-mediated endotoxin shock in animal models. We have investigated the effect of PMB on responses mediated by the P2X(7)R in HEK293 and K562 cells transfected with P2X(7) cDNA and in mouse and human macrophages. In addition, in view of the potential exploitation of P2X(7)-directed agonists in antitumor therapy, we also investigated the effect of PMB in B lymphocytes from patients affected by chronic lymphocytic leukemia. PMB, at an optimal concentration dependent on the given cell type,greatly potentiated the effect of nucleotide-mediated P2X(7), stimulation. In particular, ATP-mediated Ca2+ influx, plasma membrane permeabilization, and cytotoxicity were enhanced to an extent that, in the presence of PMB, cells were killed by otherwise ineffective nucleotide concentrations. The synergistic effect due to the combined application of ATP and PMB was prevented by incubation with the irreversible P2X blocker oxidized ATP (oATP), but not with the reversible antagonist 1-(N,O-bis(1,5-isoquinolinesulfonyl)-N-methyl-(L)-tyrosyl)-4-phenilpiperaiine (KN-62). Cells lacking P2X(7) were fully insensitive to the combined stimulation with PMB and ATP. Furthermore, PMB at the concentrations used had no untoward effects on cell viability. These results point to PMB as a useful tool for the modulation of P2X(7)R function and suggest that care should be used in the evaluation of ATP-stimulated immune cell responses in the presence of PMB as they may not solely be affected by removal of contaminating LPS.