Sauvage M, Hinglais N, Mandet C, Badier C, Deslandes F, Michel J B, Jacob M P
INSERM U 460, UFR de Médecine X. Bichat, 16, rue H. Huchard, F-75870 Paris Cedex 18, France.
Cell Tissue Res. 1998 Feb;291(2):305-14. doi: 10.1007/s004410051000.
Several in vitro studies have previously demonstrated that the addition of TGF-beta to aortic smooth muscle cells or skin fibroblasts stimulates elastin synthesis. It is not clear however whether, in vivo, TGF-beta participates in the regulation of elastin synthesis, especially in physiological conditions. The aim of our study was to explore the localization of elastin mRNA and TGF-beta1 in the rat thoracic aorta (an elastic artery) and caudal artery (a muscular artery). Elastin mRNA was localized by in situ hybridization and quantified using Northern blot analysis. TGF-beta1 was detected using immunohistochemistry. The study was carried out as a function of age (rats of 3, 10, 20, and 30 months). We observed that TGF-beta1 immunoreactivity is present predominantly, but not exclusively, at the sites of elastin synthesis as determined by elastin mRNA detection: in smooth muscle cells in the aorta and in endothelial cells in the caudal artery. The ability of exogenously added TGF-beta1 (0.001-10 ng/ml) to modulate the steady-state levels of elastin mRNA in primary cultures of endothelial cells, smooth muscle cells, and fibroblasts isolated from the thoracic aorta was also studied. At the highest concentration used, elastin mRNA levels increased 5-fold in endothelial cells and 11-fold in smooth muscle cells. The demonstration that TGF-beta1 immunoreactivity is present at the sites of elastin synthesis in the thoracic aorta and in the caudal artery and the observation that TGF-beta1 induces an increase in elastin mRNA levels in cultured endothelial cells and smooth muscle cells suggest that TGF-beta1 may be implicated, at least in part, in the physiological regulation of elastin gene expression.
此前多项体外研究表明，向主动脉平滑肌细胞或皮肤成纤维细胞中添加转化生长因子-β（TGF-β）可刺激弹性蛋白合成。然而，在体内TGF-β是否参与弹性蛋白合成的调节尚不清楚，尤其是在生理条件下。我们研究的目的是探索弹性蛋白mRNA和TGF-β1在大鼠胸主动脉（弹性动脉）和尾动脉（肌性动脉）中的定位。通过原位杂交对弹性蛋白mRNA进行定位，并使用Northern印迹分析进行定量。采用免疫组织化学法检测TGF-β1。该研究根据年龄（3、10、20和30个月的大鼠）进行。我们观察到，如通过弹性蛋白mRNA检测所确定的，TGF-β1免疫反应性主要（但并非唯一）存在于弹性蛋白合成部位：在主动脉的平滑肌细胞和尾动脉的内皮细胞中。我们还研究了外源性添加的TGF-β1（0.001 - 10 ng/ml）对从胸主动脉分离的内皮细胞、平滑肌细胞和成纤维细胞原代培养物中弹性蛋白mRNA稳态水平的调节能力。在所使用的最高浓度下，内皮细胞中弹性蛋白mRNA水平增加了5倍，平滑肌细胞中增加了11倍。TGF-β1免疫反应性存在于胸主动脉和尾动脉的弹性蛋白合成部位，以及TGF-β1可诱导培养的内皮细胞和平滑肌细胞中弹性蛋白mRNA水平升高这一观察结果表明，TGF-β1可能至少部分参与弹性蛋白基因表达的生理调节。
