Shinomiya H, Nakano M
Department of Microbiology, Jichi Medical School, Tochigiken, Japan.
J Immunol. 1987 Oct 15;139(8):2730-6.
C3H/HeJ mice are hyporesponsive to the biologic effects of bacterial lipopolysaccharide (LPS). The defect in the strain of mice is believed to be due to the expression of a mutant allele designated Lpsd at the chromosome four locus. The molecular basis of this hyporesponsiveness is not known, but it may result from some defective membrane signal transductions. To examine this possibility, we compared the abilities of interleukin 1 (IL-1) production by C3H/HeJ macrophages with those by C3H/He macrophages (LPS responsive) after stimulation with the calcium ionophore A23187 or phorbol myristate acetate (PMA). A23187 induced IL-1 production by C3H/He macrophages, but it did not induce IL-1 production by C3H/HeJ macrophages and neither did LPS. However, it had the ability to increase intracellular free Ca2+ in C3H/HeJ macrophages as well as in C3H/He macrophages, this being examined by the changes in cytosolic Ca2+ in the macrophages by using Quin 2. In contrast, PMA was able to induce IL-1 production by both C3H/He and C3H/HeJ macrophages without increasing intracellular Ca2+. Since polymyxin B did not inhibit A23187- or PMA-induced IL-1 production by C3H/He macrophages, these results are not due to the little amount of LPS in culture medium, but due to their own characteristics. A calmodulin antagonist W-7 effectively inhibited A23187-induced IL-1 production by C3H/He macrophages. However, it hardly inhibited LPS-induced IL-1 production except at high concentration, and it caused no inhibition of the PMA-stimulated one. These results suggest that the blocking sites expressed phenotypically by the Lpsd are shared by LPS- and A23187-stimulated cellular processes, although the actions of LPS and A23187 are different from each other. In addition to the direct study with LPS or lipid A, A23187 should provide another useful approach to clarify the molecular mechanisms of Lpsd defect in C3H/HeJ macrophages.
C3H/HeJ小鼠对细菌脂多糖（LPS）的生物学效应反应低下。该品系小鼠的缺陷被认为是由于在四号染色体位点上表达了一个名为Lpsd的突变等位基因。这种反应低下的分子基础尚不清楚，但可能是由于某些有缺陷的膜信号转导所致。为了检验这种可能性，我们比较了用钙离子载体A23187或佛波酯（PMA）刺激后，C3H/HeJ巨噬细胞与C3H/He巨噬细胞（对LPS有反应）产生白细胞介素1（IL-1）的能力。A23187可诱导C3H/He巨噬细胞产生IL-1，但不能诱导C3H/HeJ巨噬细胞产生IL-1，LPS也不能。然而，它有能力增加C3H/HeJ巨噬细胞以及C3H/He巨噬细胞内的游离Ca2+，这是通过使用喹啉2检测巨噬细胞胞质Ca2+的变化来确定的。相比之下，PMA能够诱导C3H/He和C3H/HeJ巨噬细胞产生IL-1，而不会增加细胞内Ca2+。由于多粘菌素B不抑制A23187或PMA诱导C3H/He巨噬细胞产生IL-1，这些结果不是由于培养基中LPS含量少，而是由于它们自身的特性。钙调蛋白拮抗剂W-7有效抑制A23187诱导C3H/He巨噬细胞产生IL-1。然而，除高浓度外，它几乎不抑制LPS诱导的IL-1产生，也不抑制PMA刺激的IL-1产生。这些结果表明，Lpsd表型表达的阻断位点在LPS和A23187刺激的细胞过程中是共有的，尽管LPS和A23187的作用彼此不同。除了用LPS或脂质A进行直接研究外，A23187应该为阐明C3H/HeJ巨噬细胞中Lpsd缺陷的分子机制提供另一种有用的方法。
