Lundberg M S, Sadhu D N, Grumman V E, Chilian W M, Ramos K S
Department of Medical Physiology, Texas A&M University, College Station 77843, USA.
In Vitro Cell Dev Biol Anim. 1995 Sep;31(8):595-600. doi: 10.1007/BF02634312.
The occurrence of vascular domains with specific biological and pharmacological characteristics suggests that smooth muscle cells in different arteries may respond differentially to a wide range of environmental stimuli. To determine if some of these vessel-specific differences may be attributable to mechano-sensitive gene regulation, the influence of cyclical stretch on the expression of actin isoform and alpha 1B-adrenoceptor genes was examined in aortic and coronary smooth muscle cells. Cells were seeded on an elastin substrate and subjected to maximal stretching (24% elongation) and relaxation cycles at a frequency of 120 cycles/min in a Flexercell strain unit for 72 h. Total RNA was extracted and hybridized to radiolabeled cDNA probes to assess gene expression. Stretch caused a greater reduction of actin isoform mRNA levels in aortic smooth muscle cells as compared to cells from the coronary artery. Steady-state mRNA levels of alpha 1B-adrenoceptor were also decreased by cyclical stretch in both cell types but the magnitude of the response was greater in coronary smooth muscle cells. No changes in alpha 1B-adrenoceptor or beta/gamma-actin steady-state mRNA levels were observed in H4IIE cells, a nonvascular, immortalized cell line. The relative gene expression of heat shock protein 70 was not influenced by the cyclic stretch regimen in any of these cell types. These results suggest that stretch may participate in the regulation of gene expression in vascular smooth muscle cells and that this response exhibits some degree of cell-specificity.
具有特定生物学和药理学特性的血管区域的出现表明，不同动脉中的平滑肌细胞可能对多种环境刺激有不同反应。为了确定这些血管特异性差异中的一些是否可能归因于机械敏感基因调控，研究了周期性拉伸对主动脉和冠状动脉平滑肌细胞中肌动蛋白异构体和α1B -肾上腺素能受体基因表达的影响。将细胞接种在弹性蛋白基质上，并在Flexercell应变装置中以120次循环/分钟的频率进行最大拉伸（24%伸长）和松弛循环，持续72小时。提取总RNA并与放射性标记的cDNA探针杂交以评估基因表达。与冠状动脉细胞相比，拉伸导致主动脉平滑肌细胞中肌动蛋白异构体mRNA水平的降低更大。两种细胞类型中，周期性拉伸也使α1B -肾上腺素能受体的稳态mRNA水平降低，但冠状动脉平滑肌细胞中的反应幅度更大。在非血管永生化细胞系H4IIE细胞中未观察到α1B -肾上腺素能受体或β/γ-肌动蛋白稳态mRNA水平的变化。在任何这些细胞类型中，热休克蛋白70的相对基因表达均不受周期性拉伸方案的影响。这些结果表明，拉伸可能参与血管平滑肌细胞中基因表达的调控，并且这种反应表现出一定程度的细胞特异性。
