Cytochrome P-450-dependent omega-oxidation of leukotriene B4 in rodent and human epidermis.
Cytochrome P-450-dependent omega-oxidation of leukotriene B4 in rodent and human epidermis.
复制标题
啮齿动物和人类表皮中白三烯 B4 的细胞色素 P-450 依赖性 omega 氧化。
DOI：
10.1111/1523-1747.ep12277578
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Bickers,DR
中科院分区：
文献类型：
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作者：
Mukhtar,H;Bik,DP;Ruzicka,T;Merk,HF;Bickers,DR
白三烯B4（LTB 4，5-12-dihydroxy 6，8，10，14-eicosatetraenoic acid）是花生四烯酸的酶催化氧化产物，是一种主要的炎症介质。人多形核白细胞和啮齿类动物肝微粒体将LTB 4分解代谢为20-OH-LTB 4和20-COOH-LTB 4，这是由称为LTB 4 ω-羟化酶的细胞色素P-450催化的反应介导的。在这项研究中，我们研究了LTB 4在大鼠，豚鼠和人表皮中的催化作用。在存在氧气、NADPH和从新生大鼠（3.0 mg）或成年豚鼠（2.6 mg）制备的表皮微粒体的情况下，3 H-LTB 4（9 μM）孵育60 min，导致形成20-OH-LTB 4和20-COOH-LTB 4。代谢物鉴别基于高压液相色谱法与高纯度参比标准品的共色谱法。20-OH-LTB 4和20-COOH-LTB 4的形成伴随着LTB 4的消失。20-OH-LTB 4的形成速率是20-COOH-LTB 4的9-12倍。产物形成与煮沸的微粒体可以忽略不计，需要NADPH和氧气，与孵育时间和蛋白质呈线性关系，在pH 7.4时最大。一氧化碳或2-二乙基氨基乙基-2，2-二苯基戊酸酯盐酸盐（SKF-525 A）（1 mM）可抑制LTB 4-ω-羟化酶活性（>90%），而α-萘醌仅产生中度（13%）或无影响。新生大鼠局部应用3-甲基胆蒽和其他表皮单加氧酶活性的常规诱导剂（100 mg/kg，单次给药）未导致表皮LTB 4-ω-羟化酶活性增加。向原代人角质形成细胞中加入3 H-LTB 4（30 nmol），然后在37°C下孵育，导致LTB 4随时间依赖性消失，并在培养基中出现20-OH-LTB 4和20-COOH-LTB 4。这些结果表明，LTB 4是分解代谢的细胞色素P-450依赖酶系统在啮齿动物和人类皮肤，这可能参与调节这种促炎脂质在该组织中的作用。
Leukotriene B4(LTB4, 5-12-dihydroxy 6,8,10,14-eicosatetraenoic acid), an enzyme-catalyzed oxidation product of arachidonic acid, is a major inflammatory mediator. Human polymorphonuclar leukocytes and rodent hepatic microsomes catabolize LTB4to 20-OH-LTB4and 20-COOH-LTB4, which is mediated by a cytochrome P-450 catalyzed reaction termed the LTB4ω-hydroxylase. In this study we investigated the catabolism of LTB4in rat, guinea pig, and human epidermis. The incubation of3H-LTB4(9 μM) for 60 mm in the presence of oxygen, NADPH, and epidermal microsomes prepared from neonatal rat (3.0 mg) or adult guinea pig (2.6 mg) resulted in the formation of 20-OH-LTB4and 20-COOH-LTB4. Metabolite identification was based on co-chromatography on high pressure liquid chromatography with highly purified reference standards. The formation of 20-OH-LTB4and 20-COOH-LTB4was accompanied by the disappearance of LTB4. The rate of formation of 20-OH-LTB4was 9-12-fold higher than that of 20-COOH-LTB4. Product formation was negligible with boiled microsomes, required NADPH and oxygen, was linear with respect to incubation time and protein, and was maximal at pH 7.4. LTB4-ω-hydroxylase activity was inhibited (>90%) by carbon monoxide or 2-diethylaminoethyl-2,2-diphenylvalerate hydrochloride (SKF-525A) (1 mM), whereas α-naphthoflavone produced only moderate (13%) or no effects. Topical application of 3-methylcholanthrene and other conventional inducers of epidermal monooxygenase activities to neonatal rats (100 mg/kg, single treatment) did not result in an increase in epidermal LTB4-ω-hydroxylase activity. The addition of3H-LTB4(30 nmoles) to primary human keratinocytes followed by incubation at 37°C resulted in time-dependent disappearance of LTB4and appearance of 20-OH-LTB4and 20-COOH-LTB4in the medium. These results suggest that LTB4is catabolized by the cytochrome P-450-dependent enzyme system in rodent and human skin and that this may participate in modulating the effects of this proinflammatory lipid in this tissue.