Differential lymphocyte growth-modifying effects of oxidants: changes in cytosolic Ca+2.
Differential lymphocyte growth-modifying effects of oxidants: changes in cytosolic Ca+2.
复制标题
氧化剂对淋巴细胞生长的差异调节作用：胞质 Ca 2 的变化。
DOI：
10.1016/0041-008x(89)90296-2
复制
发表时间：
1989
影响因子：
3.8
通讯作者：
Lawrence,DA
中科院分区：
文献类型：
--
作者：
Duncan,DD;Lawrence,DA
胞质Ca+2浓度（[Ca+2]i）的增加是有丝分裂原刺激的淋巴细胞中观察到的最早变化之一，并且是通常导致细胞周期进程启动的信号转导的结果。然而，[Ca+2] i增加也与细胞毒性相关。我们已经确定了是否调制的[Ca+2] i参与观察亚致死浓度的氧化剂的细胞的功能失活。具体地说，在用不同氧化剂处理的小鼠脾淋巴细胞中测定[Ca+2] i，以确定氧化应激是否干扰有丝分裂原刺激的[Ca +2]i增加，氧化剂本身是否调节[Ca+2]i，如果是，氧化剂的这种Ca+2调节对淋巴细胞对有丝分裂原的反应是否具有刺激或抑制作用。所采用的氧化剂是铜菲咯啉（CuP;表面硫醇氧化剂）、N-乙基马来酰亚胺（NEM;渗透硫醇烷基化剂）、过氧化氢（H2 O2;在细胞内产生羟基自由基）和辐射（Cs 137;通过辐解产生羟基自由基）。所有处理过的细胞的生长受到同样的抑制后，刺激与Con A或PMA/A23187，这表明所有的氧化剂抑制细胞功能所需的激活远端的转导途径所利用的Con A，但绕过PMA/A23187。完全抑制ConA刺激的增殖的CuP、NEM和辐射剂量对静息或丝裂原刺激的[Ca+2]i变化几乎没有影响，但完全抑制增殖的H2 O2剂量增加了未刺激细胞的[Ca+2] i，并阻止了ConA正常引起的增加。细胞内和细胞外Ca+2均参与了未刺激细胞[Ca+2] i的增加。升高[Ca+2] i足以降低反应性，因为用离子载体A23187增加[Ca+2] i可使淋巴细胞对Con A的反应性降低。与A23187不同，H2 O2不能与PMA协同作用，这表明H2 O2诱导的[Ca+2]增加主要向细胞传递负信号。ConA和PMA激活的淋巴细胞对[Ca+2] i的利用也不同。当细胞用H2 O2处理时，细胞内和细胞外Ca+2分别与BAPTA和EGTA螯合，对ConA的反应恢复。在这些条件下，需要更高浓度的H2 O2来抑制对Con A的反应。我们的研究结果表明，信号转导可能会受到损害的细胞与过氧化氢处理，但不与铜，NEM，或辐射处理的细胞。此外，H2 O2通过Ca+2依赖性和非依赖性途径抑制对Con A的反应，而CuP、NEM和辐射仅通过Ca+2非依赖性途径抑制对Con A的反应。
An increase in the concentration of cytosolic Ca+2([Ca+2]i) is among the earliest changes seen in mitogen-stimulated lymphocytes and is a consequence of signal transduction which usually results in the initiation of cell cycle progression. However, increased [Ca+2]ihas also been correlated with cytoxicity. We have determined whether modulations of [Ca+2]iare involved in the functional inactivation of cells observed with sublethal concentrations of oxidants. Specifically, [Ca+2]iwas measured in mouse splenic lymphocytes that were treated with different oxidants in order to determine if oxidative stress interferes with mitogen-stimulated increases in [Ca+2]i, if oxidants themselves modulated [Ca+2]i, and, if so, whether such Ca+2modulations by oxidants had stimulatory or inhibitory effects on the response of lymphocytes to mitogens. The oxidants employed were copper phenanthroline (CuP; surface thiol oxidizer), N-ethyl maleimide (NEM; permeant thiol alkylator), hydrogen peroxide (H2O2; generates hydroxyl radical within the cell), and radiation (Cs137; generates hydroxyl radical by radiolysis). Growth of all treated cells was equally inhibited upon stimulation with Con A or PMA/A23187, suggesting that all the oxidants inhibited cell functions required distal in activation to the transduction pathway utilized by Con A but bypassed by PMA/A23187. Doses of CuP, NEM, and radiation which fully inhibited Con A-stimulated proliferation had little effect on resting or mitogen-stimulated changes of [Ca+2]i, but H2O2doses which fully inhibited proliferation increased [Ca+2]iin unstimulated cells and prevented the increase normally caused by Con A. Both intra- and extracellular Ca+2contributed to the increased [Ca+2]iseen in unstimulated cells. An elevated [Ca+2]iwas sufficient to reduce responsiveness, since pharmacologically increasing the [Ca+2]iwith the ionophore A23187 rendered lymphocytes less responsive to Con A. Unlike A23187, H2O2was unable to synergize with PMA, suggesting that the H2O2-induced increase of [Ca+2]idelivered predominantly negative signals to the cell. The results also suggest that [Ca+2]iutilization by Con A versus PMA-activated lymphocytes must be different. When cells were treated with H2O2under conditions where intracellular and extracellular Ca+2were chelated with BAPTA and EGTA, respectively, the response to Con A was restored. Under these conditions, higher concentrations of H2O2were required to inhibit the response to Con A. Our results indicate that signal transduction may be compromised in cells treated with H2O2, but not in cells treated with CuP, NEM, or radiation. In addition, H2O2inhibited the response to Con A via Ca+2-dependent and independent pathways, but CuP, NEM, and radiation inhibited the response to Con A via Ca+2-independent pathways only.