Secretion of platelet-activating factor acetylhydrolase following phorbol ester-stimulated differentiation of HL-60 cells.
Secretion of platelet-activating factor acetylhydrolase following phorbol ester-stimulated differentiation of HL-60 cells.
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DOI：
10.1006/abbi.1993.1144
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发表时间：
1993-03
影响因子：
3.9
通讯作者：
H. Narahara;R. Frenkel;J. Johnston
中科院分区：
文献类型：
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作者：
H. Narahara;R. Frenkel;J. Johnston
血小板活化因子(PAF)在从炎症到生殖生物学等一系列生物学过程中发挥着重要作用。我们已经报道过，在妊娠后期，母体血浆中失活这种有效的金龟子的酶，PAF-乙酰水解酶(PAF-AH)是减少的。这种酶与血浆脂蛋白部分有关，因此它的组织来源被认为是肝脏。Prescott和他的同事(J.Biol.化学。265,17381,1990年)报道了大鼠肝细胞系(HepG2细胞)和人外周巨噬细胞都分泌血浆型PAF-AH。我们以前已经证明，注射地塞米松或甲羟孕酮会导致大鼠血浆PAF-AH活性增加，而雌激素会导致血浆PAF-AH活性下降。为了阐明PAF-AH产生的激素调节机制，我们采用单核-巨噬细胞模型系统研究了PAF-AH在分化过程中的分泌。在本研究中，我们证明了在12-O-十四酰佛波醇-13-乙酸酯(TPA)刺激下，髓系白血病细胞系(HL-60)在分化为巨噬细胞时产生并分泌PAF-AH到特定的培养液中。从未经刺激的HL-60细胞获得的培养液中不含有可检测到的PAF-AH活性。TPA刺激后，PAF-AH活性呈剂量和时间依赖性增加。经TPA处理后的HL-60细胞在培养过程中细胞数无明显增加。TPA诱导的贴壁细胞排除了台盼蓝，不释放乳酸脱氢酶活性，从而排除了细胞裂解。放线菌素D和放线菌亚胺可抑制PAF-AH活性的升高。地塞米松和甲羟孕酮可显著增加细胞分泌PAF-AH，而雌激素无明显作用。细菌内毒素(脂多糖)以剂量依赖的方式抑制这些细胞产生PAF-AH。在HL-60细胞分化过程中PAF-AH的分泌被刺激，并被内毒素和类固醇激素调节，这可能为研究炎症反应和妊娠过程中PAF的代谢提供一个有用的模型系统。
Platelet-activating factor (PAF) plays an important role in a number of biological processes ranging from inflammation to reproductive biology. We have reported that the enzyme that inactivates this potent autacoid, PAF-acetylhydrolase (PAF-AH), is decreased in maternal plasma during the latter stages of pregnancy. This enzyme is associated with the plasma lipoprotein fraction and therefore its tissue origin was thought to be the liver. Prescott and colleagues (J. Biol. Chem. 265, 17381, 1990) have reported that both a rat liver cell line (HepG2 cells) and human peripheral macrophages secrete PAF-AH of the plasma type. We have shown previously that the injection of rats with dexamethasone or medroxyprogesterone causes an increase and estrogen a decrease in the plasma PAF-AH activity. To clarify the mechanism of hormonal regulation of PAF-AH production, we employed a monocyte-macrophage model system to investigate the secretion of PAF-AH during differentiation. In the present study, we have demonstrated that a myelocytic leukemic cell line (HL-60) produces and secretes PAF-AH into a defined medium when the cells are differentiated into macrophages following stimulation by 12-O-tetradecanoylphorbol-13-acetate (TPA). The medium obtained from unstimulated HL-60 cells did not contain detectable amounts of PAF-AH activity. Stimulation with TPA caused a dose- and time-dependent increase in PAF-AH activity in the media. No increase in cell number was observed in the HL-60 cells during the culture period after the cells were treated with TPA. Cell lysis was excluded by the demonstration that the TPA-induced adherent cells excluded trypan blue and did not release lactate dehydrogenase activity into the medium. The increase in PAF-AH activity was inhibited by actinomycin D and cycloheximide. Dexamethasone and medroxyprogesterone markedly increased the secretion of PAF-AH by these cells, while estrogen was without effect. Bacterial endotoxin (lipopolysaccharide, LPS) inhibited the production of PAF-AH by these cells in a dose-dependent manner. The stimulation of PAF-AH secretion during differentiation of HL-60 cells and its modulation by LPS and steroid hormones may provide a useful model system for studying PAF metabolism during the inflammatory response and pregnancy.