Novel transcripts of Nox1 are regulated by alternative promoters and expressed under phenotypic modulation of vascular smooth muscle cells
Novel transcripts of Nox1 are regulated by alternative promoters and expressed under phenotypic modulation of vascular smooth muscle cells
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DOI：
10.1042/bj20060300
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发表时间：
2006-09-01
影响因子：
4.1
通讯作者：
Yabe-Nishimura, Chihiro
中科院分区：
文献类型：
--
作者：
Arakawa, Noriaki;Katsuyama, Masato;Yabe-Nishimura, Chihiro
NADPH氧化酶与多种心血管疾病的发病机制有关。在血管平滑肌细胞（VSMC）中，NOX 1（NADPH氧化酶1）（NADPH氧化酶的催化亚基）的表达较低，并且在血管活性因子的刺激下被诱导，而其在结肠上皮细胞中大量表达。为了阐明这种细胞特异性表达的调控机制，探索了指导NOX 1基因转录的上游区域。在P53 LMACO 1细胞中，一种源自小鼠VSMCs的细胞系，分离到两种新的Nox 1 mRNA种类，c型和f型。这些转录物含有不同于结肠型mRNA（a型）的5 '非翻译区，并编码额外的28个氨基酸的N-末端肽。当这些转录本融合到c-myc标签，并在人胚肾293细胞中表达，一小部分翻译的蛋白质的大小包含额外的肽。由c-和f-型mRNA编码的蛋白质表现出与a-型形式的活性相当的超氧化物产生活性。a型mRNA在结肠和完整的主动脉中表达，而c型mRNA在原代培养的从主动脉外植体迁移的VSMCs中检测到，在钢丝损伤模型的血管组织中和在血管紧张素II输注的小鼠的胸主动脉中。C型mRNA的启动子区域在P53 LMACO 1细胞中表现出转录活性，但在小鼠结肠上皮细胞系MCE 301细胞中没有。这些结果表明，Nox 1基因的表达是由替代启动子和新的C型转录下诱导表型调制的VSMCs。
NADPH oxidase is implicated in the pathogenesis of various cardiovascular disorders. In vascular smooth muscle cells (VSMC), expression of NOX1 (NADPH oxidase 1), a catalytic subunit of NADPH oxidase, is low and is induced upon stimulation by vasoactive factors, while it is abundantly expressed in colon epithelial cells. To clarify the regulatory mechanisms underlying such cell-specific expression, the upstream regions directing transcription of the NOX1 gene were explored. In P53LMACO1 cells, a cell line originated from mouse VSMCs, two novel Nox1 mRNA species, the c- and f-type, were isolated. These transcripts contained 5'-untranslated.regions that differed from the colon type mRNA (a-type) and encoded an additional N-terminal peptide of 28 amino acids. When these transcripts were fused to the c-myc tag and expressed in human embryonic kidney 293 cells, a fraction of translated proteins demonstrated the size containing the additional peptide. Proteins encoded by the c- and f-type mRNAs exhibited superoxide-producing activities equivalent to the activity of the a-type form. The a-type mRNA was expressed in the colon and in the intact aorta, whereas the c-type mRNA was detected in the primary cultured VSMCs migrated from aortic explants, in vascular tissue of a wire-injury model and in the thoracic aorta of mice infused with angiotensin II. The promoter region of the c-type mRNA exhibited transcriptional activity in P53LMACO1 cells, but not in MCE301 cells, a mouse colon epithelial cell line. These results suggest that expression of the Nox1 gene is regulated by alternative promoters and that the novel c-type transcript is induced under phenotypic modulation of VSMcs.