B-Myb regulates the A2B adenosine receptor in vascular smooth muscle cells
B-Myb regulates the A2B adenosine receptor in vascular smooth muscle cells
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DOI：
10.1002/jcb.21586
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发表时间：
2008-04-15
影响因子：
4
通讯作者：
Ravid, Katya
中科院分区：
文献类型：
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作者：
Hilaire, Cynthia St.;Yang, Dan;Ravid, Katya
已描述A（2B）腺苷受体（A（2B）AR）控制各种血管功能，包括抑制平滑肌细胞增殖。在此，我们试图了解A（2B）AR基因在主动脉血管平滑肌细胞（VSMCs）中的表达调控，重点是增殖阶段。用A（2B）AR-β-gal主动脉VSMC进行的测定显示，当诱导细胞退出细胞周期停滞时，β-gal表达上调，其中内源性A（2B）AR基因启动子驱动原核β-半乳糖苷酶（P-gal）而不是内源性A（2B）AR基因的表达。类似地，A（2B）AR mRNA的水平在增殖的主动脉VSMC中上调。在寻找相关机制时，注意到A（2B）AR基因启动子含有增殖诱导转录因子B-Myb的几个推定结合位点。使用与报告基因连接的小鼠A（2B）AR基因上游5'区的克隆，产生B-Myb位点缺失突变体。确定B-Myb上调A（2B）AR基因启动子，并且特异性启动子结合位点被鉴定为功能性的。因此，B-Myb还提高了内源性A（2B）AR mRNA和受体活性，并且这种活性降低了细胞增殖。我们的数据是新颖的，因为它们表明这种增殖抑制A（2B）AR本身是由B-Myb调节的诱导型受体。
The A(2B) adenosine receptor (A(2B)AR) has been described to control various vascular functions, including inhibition of smooth muscle cell proliferation. Here, we sought to understand the regulation of A(2B)AR gene expression in aortic vascular smooth muscle cells (VSMCs), with a focus on the proliferation phase. Assays with A(2B)AR-beta-gal aortic VSMCs, in which the endogenous A(2B)AR gene promoter drives the expression of prokaryotic beta-galactosidase (P-gal) instead of the endogenous A(2B)ARgene, show that beta-gal expression is Upregulated when the cells are induced to exit from cell cycle arrest. Similarly, the level of A(2B)AR mRNA is upregulated in proliferating primary aortic VSMCs. In search of related mechanisms, it was noted that the A(2B)AR gene promoter contains several putative binding sites for the proliferation-inducing transcription factor, B-Myb. Using a clone of the 5' region upstream of the mouse A(2B)AR gene linked to a reporter gene, B-Myb site deletion mutants were generated. it was determined that B-Myb upregulates the A(2B)AR gene promoter, and specific promoter binding sites were identified as functional. in accordance, B-Myb also elevates endogenous A(2B)AR mRNA and receptor activity, and this activity decreases cell proliferation. Our data are novel in that they show that this proliferation-inhibiting A(2B)AR is itself an inducible receptor regulated by B-Myb.