Secretagogue-induced phosphoinositide metabolism in human leucocytes.
Secretagogue-induced phosphoinositide metabolism in human leucocytes.
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促分泌素诱导的人白细胞中的磷酸肌醇代谢。
DOI：
10.1042/bj2220307
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Freer,RJ
中科院分区：
文献类型：
--
作者：
Dougherty,RW;Godfrey,PP;Hoyle,PC;PutneyJr,JW;Freer,RJ
在人多形核白细胞（PMN）和二甲基亚砜（Me_2SO）刺激的人粒单核细胞白血病细胞系HL-60中，研究了甲酰化肽化学引诱物甲酰甲硫氨酰亮氨酰苯丙氨酸（fMet-Leu-Phe）的受体结合、溶酶体酶分泌和膜磷脂代谢之间的关系。在这两种细胞类型中，暴露于fMet-Leu-Phe（100 nM）诱导快速溶酶体酶分泌（最大释放小于30 s）和肌醇脂质磷脂酰肌醇（PtdIns）、磷脂酰肌醇4-磷酸（PtdIns 4P）、磷脂酰肌醇4，5-二磷酸[PtdIns（4，5）P2]以及磷脂酸（PtdA）的32 P标记发生显著变化。具体而言，[32 P]PtdIns和[32 P]PtdIns（4，5）P2的水平迅速下降（在10- 15 s达到峰值下降），随后在30 s及以后增加。PtdIns 4P和PtdA仅显示增加。在Me 2SO分化的HL-60细胞中，用[3 H]肌醇预标记20 h，fMet-Leu-Phe引起细胞内[3 H]肌醇磷酸含量的净增加，包括[3 H]肌醇1，4，5-三磷酸的快速增加，表明PtdIns（4，5）P2通过磷脂酶C机制发生分解。溶酶体酶分泌和磷脂代谢的变化都发生在相同的激动剂浓度范围内，时间过程相似。[3 H]fMet-Leu-Phe的结合虽然发生在相同的浓度范围内，但表现出明显较慢的动力学。虽然细胞外Ca 2+耗竭配体诱导的聚磷酸肌醇营业额没有影响，PtdIns营业额，PtdA标记和溶酶体酶分泌严重减少。这些研究表明，受体介导的磷脂周转增强与特定的生物反应fMet-Leu-Phe。此外，该结果与磷脂酶C介导的PtdIns（4，5）P2降解（导致三磷酸肌醇形成）是中性粒细胞刺激-分泌偶联途径的早期步骤的想法一致。这两种反应和平衡结合条件之间缺乏相关性表明，这些参数要么对配体-受体相互作用的速率有反应，要么完全生物反应只需要部分占据。
The relationship between receptor binding of the formylated peptide chemoattractant formylmethionylleucylphenylalanine (fMet-Leu-Phe), lysosomal enzyme secretion and metabolism of membrane phospholipids was evaluated in both human polymorphonuclear leucocytes (PMN) and the dimethyl sulphoxide (Me2SO)-stimulated human myelomonocytic HL-60 leukaemic cell line. In both cell types, exposure to fMet-Leu-Phe (100 nM) induced rapid lysosomal enzyme secretion (maximal release less than 30 s) and marked changes in the 32P-labelling of the inositol lipids phosphatidylinositol (PtdIns), phosphatidylinositol 4-phosphate (PtdIns4P), phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] as well as phosphatidic acid (PtdA). Specifically, levels of [32P]PtdIns and [32P]PtdIns(4,5)P2 decreased rapidly (peak decrease at 10-15s), with a subsequent increase at 30 s and later. PtdIns4P and PtdA showed only an increase. In Me2SO-differentiated HL-60 cells prelabelled with [3H]inositol for 20 h, fMet-Leu-Phe caused a net increase in the cellular content of [3H]inositol phosphates, including a rapid increase in [3H]inositol 1,4,5-trisphosphate, suggesting that PtdIns(4,5)P2 breakdown occurs by a phospholipase C mechanism. Both lysosomal enzyme secretion and changes in phospholipid metabolism occur over the same agonist concentration range with a similar time course. Binding of [3H]fMet-Leu-Phe, although occurring over the same concentration range, exhibited markedly slower kinetics. Although depletion of extracellular Ca2+ had no effect on ligand-induced polyphosphoinositide turnover, PtdIns turnover, PtdA labelling and lysosomal enzyme secretion were severely curtailed. These studies demonstrate a receptor-mediated enhancement of phospholipid turnover that correlates with a specific biological response to fMet-Leu-Phe. Further, the results are consistent with the idea that phospholipase C-mediated degradation of PtdIns(4,5)P2, which results in the formation of inositol trisphosphate, is an early step in the stimulus-secretion coupling pathway of the neutrophil. The lack of correlation between these two responses and the equilibrium-binding condition suggests that either these parameters are responsive to the rate of ligand-receptor interaction or only fractional occupation is required for a full biological response.