Tissue sources of cytochrome P450 4A and 20-HETE synthesis in rabbit lungs
Tissue sources of cytochrome P450 4A and 20-HETE synthesis in rabbit lungs
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DOI：
10.1165/ajrcmb.19.1.3145
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发表时间：
1998-07-01
影响因子：
6.4
通讯作者：
Jacobs, ER
中科院分区：
文献类型：
--
作者：
Zhu, DL;Effros, RM;Jacobs, ER
我们之前报道过，20-羟基二十碳四烯酸（20-HETE）是人肺组织中花生四烯酸（AA）的内源性细胞色素P450 (cP450) 4A代谢物，是一种有效的环氧化酶依赖性肺动脉血管扩张剂。在本研究中，我们确定了兔肺中cP450 4A免疫特异性蛋白、信使RNA （mRNA）和20-HETE合成的来源。外周肺组织微粒体、气道、小血管和大血管以及肺泡巨噬细胞裂解物均表达与大鼠肝脏cP450 4A1一抗交叉反应的类似50 kD的蛋白。外周肺组织、小、大肺动脉、气道和小肺动脉分离的血管平滑肌细胞在AA作用下产生20-HETE。cP450 4A6/4A7 mRNA的表达可通过逆转录聚合酶链反应检测，该反应采用异构体特异性探针和从显微解剖的小肺动脉中提取的5 μ g总RNA。这些数据表明，小肺动脉表达cP450 4A蛋白，来源于这些动脉的血管平滑肌细胞合成20-HETE。此外，cP450 4A似乎广泛分布于兔组织中，这提高了非血管组织产生的20-HETE可能在肺循环中作为旁分泌因子的可能性。
We previously reported that 20-hydroxyeicosatetraenoic acid (20-HETE) is an endogenous cytochrome P450 (cP450) 4A metabolite of arachidonic acid (AA) in human lung tissue, and is a potent cyclooxygenase-dependent vasodilator of isolated pulmonary arteries. In the present investigations, we identified sources of cP450 4A immunospecific protein, messenger RNA (mRNA), and 20-HETE synthesis in rabbit lungs. Microsomes of peripheral lung tissue, airways, small and large vessels, and lysates of alveolar macrophages all express proteins of similar to 50 kD which cross-reacted with a primary antibody raised against rat liver cP450 4A1. Peripheral lung tissue, small and large pulmonary arteries, airways, and isolated vascular smooth muscle cells from small pulmonary arteries produced 20-HETE when incubated with AA. Expression of cP450 4A6/4A7 mRNA was readily detectable by reverse transcription-polymerase chain reaction using isoform-specific probes and 5 mu g total RNA extracted from microdissected small pulmonary arteries. These data demonstrate that small pulmonary arteries express cP450 4A proteins and vascular smooth muscle cells derived from these arteries synthesize 20-HETE. Furthermore, cP450 4A appears to be widely distributed in rabbit tissue, raising the possibility that 20-HETE generated from nonvascular tissue could serve as a paracrine factor in the pulmonary circulation.