Samuelsson J, Hansson A, Rosendahl K, Palmblad J
Department of Medicine, Stockholm Söder Hospital, Sweden.
J Lab Clin Med. 1993 Feb;121(2):310-9.
We have assessed aspects of the stimulus response coupling for generation of superoxide anions (O2-) in polymorphonuclear granulocytes (PMNs) from patients with polycythemia vera (PV). Those cells exhibited less than half of the O2- secretion that PMNs from healthy controls did, when that response was initiated by N-formyl-methionyl-leucyl-phenylalanine (fMLP), 0.35 +/- 0.38 nmol O2-/10(6) PMNs/min and 0.83 +/- 0.45 nmol O2-/10(6) PMNs/min, respectively (p < 0.02). In contrast, when induced by phorbol myristate acetate (PMA), O2- production in PV PMNs was normal (6.9 +/- 1.1 nmol O2-/10(6) PMNs/min vs 6.9 +/- 0.6 nmol O2-/10(6) PMNs/min for control cells). In an attempt to dissect this stimulus-specific dichotomy of the oxidative responsiveness of PV PMNs, we analyzed the number of and ligand affinity for fMLP surface receptors, fMLP-induced membrane potential changes, phospholipase C-dependent production of inositol-1,4,5-trisphosphate, and the subsequent rise of cytosolic calcium concentrations. All these variables and responses were normal in PV PMNs. However, on fMLP stimulation of PV PMNs, we observed a significantly lower diacylglycerol (DAG) generation than in control cells (1.4% +/- 0.9% and 2.2% +/- 1.2% DAG of total phospholipid, respectively; p < 0.05). Furthermore, the activation of phospholipase D, measured as the formation of phosphatidylethanol (PET) in the presence of 0.5% ethanol, was impaired in PV PMNs with a similar stimulus-specific dichotomy as observed for O2- generation. Thus PET generation was significantly lower in PV cells after fMLP stimulation in relation to control cells (1.7% +/- 0.8% and 2.7% +/- 0.8% PET of total phospholipid, respectively; p < 0.01), whereas PET formation after PMA stimulation did not differ. We suggest that the impairment of phospholipase D-mediated metabolism of phosphatidylcholine in response to fMLP stimulation of polycythemia vera granulocytes may be of significance for the reduced superoxide anion formation induced by fMLP in those cells.
我们评估了真性红细胞增多症（PV）患者多形核粒细胞（PMN）中产生超氧阴离子（O2-）的刺激反应偶联的各个方面。当由N-甲酰甲硫氨酰-亮氨酰-苯丙氨酸（fMLP）引发反应时，这些细胞的O2-分泌量不到健康对照者PMN的一半，分别为0.35±0.38 nmol O2-/10(6) PMN/分钟和0.83±0.45 nmol O2-/10(6) PMN/分钟（p<0.02）。相比之下，当由佛波酯肉豆蔻酸酯乙酸酯（PMA）诱导时，PV PMN中的O2-产生正常（6.9±1.1 nmol O2-/10(6) PMN/分钟，对照细胞为6.9±0.6 nmol O2-/10(6) PMN/分钟）。为了剖析PV PMN氧化反应性的这种刺激特异性二分法，我们分析了fMLP表面受体的数量和配体亲和力、fMLP诱导的膜电位变化、磷脂酶C依赖性的肌醇-1,4,5-三磷酸的产生以及随后的细胞溶质钙浓度升高。所有这些变量和反应在PV PMN中都是正常的。然而，在fMLP刺激PV PMN时，我们观察到二酰基甘油（DAG）的产生明显低于对照细胞（分别为总磷脂的1.4%±0.9%和2.2%±1.2% DAG；p<0.05）。此外，在0.5%乙醇存在下以磷脂酰乙醇（PET）的形成来衡量的磷脂酶D的激活在PV PMN中受损，与O2-产生观察到的刺激特异性二分法相似。因此，在fMLP刺激后，PV细胞中的PET产生相对于对照细胞明显更低（分别为总磷脂的1.7%±0.8%和2.7%±0.8% PET；p<0.01），而PMA刺激后的PET形成没有差异。我们认为，磷脂酶D介导的磷脂酰胆碱代谢在真性红细胞增多症粒细胞受到fMLP刺激时受损，这可能对这些细胞中fMLP诱导的超氧阴离子形成减少具有重要意义。
