McNiff P A, Laliberte R E, Svensson L, Pazoles C J, Gabel C A
Department of Immunology and Infectious Diseases, Pfizer Inc., Groton, CT 06340, USA.
Cytokine. 1995 Feb;7(2):196-208. doi: 10.1006/cyto.1995.1027.
Tenidap is a novel anti-inflammatory and anti-arthritic agent that lowers intracellular pH and suppresses anion transport when applied to cells in vitro. Both of these parameters are known to influence pro-inflammatory cell function. To investigate whether tenidap can modulate cellular responses to cytokine stimulation, several in vitro cytokine-driven assays were characterized with respect to their tenidap sensitivity. Human monocytes treated with granulocyte-macrophage colony stimulating factor (GM-CSF) demonstrated an increased production of IL-6 as well as an increased total translational activity. Tenidap dose-dependently inhibited both cytokine-induced responses; the effect on IL-6, however, occurred at lower tenidap concentrations than those required to prevent the increase in total translational activity. In contrast, the known translational inhibitor cycloheximide did not demonstrate selectivity for IL-6; this agent decreased the GM-CSF-induced increase in total translational activity in parallel with its effects on IL-6. GM-CSF-treated monocytes also produced greater amounts of IL-1 beta in response to LPS stimulation than did non-GM-CSF-treated cells, and tenidap again suppressed this cytokine-induced activation. Human Hep3B cells treated with a combination of interleukin (IL)-1 beta and IL-6 demonstrated an acute phase-type of response. These hepatoma cells increased production of the positive acute phase protein serum amyloid A (SAA) while they decreased production of a negative acute phase protein human serum albumin (HSA). Tenidap dose-dependently inhibited the cytokine-induced increase in SAA production without effecting synthesis of HSA or total TCA-precipitable macromolecules. Importantly, the ability of tenidap to alter these various cytokine responses was not shared with piroxicam, a potent cyclooxygenase inhibitor. Finally, human neutrophils treated with either GM-CSF or tumor necrosis factor (TNF)-alpha demonstrated an increased chloride conductance as measured by the loss of radioactive chloride from 36Cl-loaded cells. When tenidap was included within the medium during cytokine stimulation, loss of radioactive chloride was prevented. Thus, tenidap inhibited the cytokine-induced increase in anion transport. Together, these results indicate that tenidap can suppress cellular activation processes induced by a variety of cytokines. This functional antagonism is not dependent on cyclooxygenase inhibition but, rather, appears to link to tenidap's unique ability to alter ionic homeostasis. These in vitro observations, therefore, may help to explain how this novel anti-inflammatory agent acts to lower acute phase proteins and IL-6 levels in man.
替硝唑是一种新型抗炎和抗关节炎药物，在体外应用于细胞时可降低细胞内pH值并抑制阴离子转运。已知这两个参数都会影响促炎细胞功能。为了研究替硝唑是否能调节细胞对细胞因子刺激的反应，对几种体外细胞因子驱动的试验进行了替硝唑敏感性特征分析。用粒细胞-巨噬细胞集落刺激因子（GM-CSF）处理的人单核细胞显示白细胞介素-6（IL-6）产生增加以及总翻译活性增加。替硝唑剂量依赖性地抑制这两种细胞因子诱导的反应；然而，对IL-6的作用发生在比防止总翻译活性增加所需浓度更低的替硝唑浓度下。相比之下，已知的翻译抑制剂环己酰亚胺对IL-6没有选择性；该药物降低GM-CSF诱导的总翻译活性增加的同时也降低了对IL-6的作用。GM-CSF处理的单核细胞对脂多糖（LPS）刺激产生的IL-1β也比未用GM-CSF处理的细胞多，替硝唑再次抑制了这种细胞因子诱导的激活。用白细胞介素（IL）-1β和IL-6联合处理的人Hep3B细胞表现出急性期样反应。这些肝癌细胞增加了阳性急性期蛋白血清淀粉样蛋白A（SAA）的产生，同时降低了阴性急性期蛋白人血清白蛋白（HSA）的产生。替硝唑剂量依赖性地抑制细胞因子诱导的SAA产生增加，而不影响HSA的合成或总三氯乙酸沉淀大分子。重要的是，替硝唑改变这些各种细胞因子反应的能力与强效环氧化酶抑制剂吡罗昔康不同。最后，用GM-CSF或肿瘤坏死因子（TNF）-α处理的人中性粒细胞显示氯化物电导增加，这是通过测量36Cl负载细胞中放射性氯化物的损失来测定的。当在细胞因子刺激期间将替硝唑加入培养基中时，放射性氯化物的损失被阻止。因此，替硝唑抑制细胞因子诱导的阴离子转运增加。总之，这些结果表明替硝唑可以抑制多种细胞因子诱导的细胞激活过程。这种功能拮抗不依赖于环氧化酶抑制，而是似乎与替硝唑改变离子稳态的独特能力有关。因此，这些体外观察结果可能有助于解释这种新型抗炎药物如何在人体中降低急性期蛋白和IL-6水平。
