Adam Rosalyn M, Eaton Samuel H, Estrada Carlos, Nimgaonkar Ashish, Shih Shu-Ching, Smith Lois E H, Kohane Isaac S, Bägli Darius, Freeman Michael R
Urological Diseases Research Center, Department of Urology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA.
Physiol Genomics. 2004 Dec 15;20(1):36-44. doi: 10.1152/physiolgenomics.00181.2004. Epub 2004 Oct 5.
Application of mechanical stimuli has been shown to alter gene expression in bladder smooth muscle cells (SMC). To date, only a limited number of "stretch-responsive" genes in this cell type have been reported. We employed oligonucleotide arrays to identify stretch-sensitive genes in primary culture human bladder SMC subjected to repetitive mechanical stimulation for 4 h. Differential gene expression between stretched and nonstretched cells was assessed using Significance Analysis of Microarrays (SAM). Expression of 20 out of 11,731 expressed genes ( approximately 0.17%) was altered >2-fold following stretch, with 19 genes induced and one gene (FGF-9) repressed. Using real-time RT-PCR, we tested independently the responsiveness of 15 genes to stretch and to platelet-derived growth factor-BB (PDGF-BB), another hypertrophic stimulus for bladder SMC. In response to both stimuli, expression of 13 genes increased, 1 gene (FGF-9) decreased, and 1 gene was unchanged. Six transcripts (HB-EGF, BMP-2, COX-2, LIF, PAR-2, and FGF-9) were evaluated using an ex vivo rat model of bladder distension. HB-EGF, BMP-2, COX-2, LIF, and PAR-2 increased with bladder stretch ex vivo, whereas FGF-9 decreased, consistent with expression changes observed in vitro. In silico analysis of microarray data using the FIRED algorithm identified c-jun, AP-1, ATF-2, and neurofibromin-1 (NF-1) as potential transcriptional mediators of stretch signals. Furthermore, the promoters of 9 of 13 stretch-responsive genes contained AP-1 binding sites. These observations identify stretch as a highly selective regulator of gene expression in bladder SMC. Moreover, they suggest that mechanical and growth factor signals converge on common transcriptional regulators that include members of the AP-1 family.
机械刺激的应用已被证明可改变膀胱平滑肌细胞（SMC）中的基因表达。迄今为止，该细胞类型中仅报道了有限数量的“拉伸反应性”基因。我们使用寡核苷酸阵列来鉴定原代培养的人膀胱SMC中对拉伸敏感的基因，这些细胞接受了4小时的重复性机械刺激。使用微阵列显著性分析（SAM）评估拉伸细胞与未拉伸细胞之间的差异基因表达。在11,731个表达基因中，有20个（约0.17%）的表达在拉伸后改变了2倍以上，其中19个基因被诱导，1个基因（FGF-9）被抑制。我们使用实时RT-PCR独立测试了15个基因对拉伸以及对血小板衍生生长因子-BB（PDGF-BB，膀胱SMC的另一种肥大刺激物）的反应性。对这两种刺激的反应中，13个基因的表达增加，1个基因（FGF-9）减少，1个基因不变。使用膀胱扩张的离体大鼠模型评估了6种转录本（HB-EGF、BMP-2、COX-2、LIF、PAR-2和FGF-9）。离体膀胱拉伸时，HB-EGF、BMP-2、COX-2、LIF和PAR-2增加，而FGF-9减少，这与体外观察到的表达变化一致。使用FIRED算法对微阵列数据进行计算机分析，确定c-jun、AP-1、ATF-2和神经纤维瘤蛋白-1（NF-1）为拉伸信号的潜在转录调节因子。此外，13个拉伸反应性基因中的9个基因的启动子含有AP-1结合位点。这些观察结果表明拉伸是膀胱SMC中基因表达的高度选择性调节因子。此外，它们表明机械信号和生长因子信号汇聚于包括AP-1家族成员在内的共同转录调节因子上。
