Ishiguro Shigeki, Akasaka Yoshikiyo, Kiguchi Hideko, Suzuki Takeya, Imaizumi Risa, Ishikawa Yukio, Ito Kinji, Ishii Toshiharu
Department of Pathology, School of Medicine, Toho University, Ohta-City, Tokyo 143-8540, Japan.
Wound Repair Regen. 2009 Jul-Aug;17(4):617-25. doi: 10.1111/j.1524-475X.2009.00511.x.
To examine the effects of basic fibroblast growth factor (bFGF) on the inhibition of alpha-smooth muscle actin (alpha-SMA) expression in dermal fibroblasts, we have established two dermal myofibroblastic cell lines positive for alpha-SMA (rat myofibroblasts [RMF] and rat myofibroblast-like [RMFL] cells) and one fibroblastic cell line negative for alpha-SMA (rat fibroblasts cells) as a model of fibroblast differentiation. In contrast to the increased expression of alpha-SMA in RMF and RMFL cells, irrespective of transforming growth factor-beta1 treatment, bFGF induced a decrease in alpha-SMA expression in the myofibroblastic cells and the reduced expression patterns of alpha-SMA differed between cells, as demonstrated by Western blot and reverse transcription polymerase chain reaction analyses. Along with the inhibition of alpha-SMA expression by bFGF, the RMF and RMFL cells also showed different activated expression of extracellular signal-regulated kinase 1/2, suggesting the involvement of extracellular signal-regulated kinase 1/2 activation in the down-regulation of alpha-SMA expression in myofibroblasts. Furthermore, an in vivo study demonstrated that bFGF administration markedly decreases the area that is positive for alpha-SMA expression in the treated wounds after day 18. In contrast, bFGF administration significantly increased the number of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining and alpha-SMA-positive cells at days 10 and 14, and reduced the double-positive cells rapidly after day 18. Collectively, the current investigation identified bFGF as a potent stimulator for the reduction of the myofibroblastic area in vivo, presumably because of its effects on the down-regulation of alpha-SMA expression as well as rapid induction of apoptosis in myofibroblasts.
为研究碱性成纤维细胞生长因子（bFGF）对抑制真皮成纤维细胞中α-平滑肌肌动蛋白（α-SMA）表达的作用，我们建立了两种α-SMA呈阳性的真皮肌成纤维细胞系（大鼠肌成纤维细胞[RMF]和大鼠肌成纤维细胞样[RMFL]细胞）以及一种α-SMA呈阴性的成纤维细胞系（大鼠成纤维细胞）作为成纤维细胞分化模型。与RMF和RMFL细胞中α-SMA表达增加不同，无论是否用转化生长因子-β1处理，bFGF均可诱导肌成纤维细胞中α-SMA表达降低，且α-SMA的降低表达模式在不同细胞间存在差异，蛋白质免疫印迹法和逆转录聚合酶链反应分析均证实了这一点。随着bFGF对α-SMA表达的抑制，RMF和RMFL细胞还表现出细胞外信号调节激酶1/2的不同激活表达，提示细胞外信号调节激酶1/2的激活参与了肌成纤维细胞中α-SMA表达的下调。此外，一项体内研究表明，在第18天后，给予bFGF可显著减少处理伤口中α-SMA表达阳性的面积。相反，在第10天和第14天，给予bFGF可显著增加末端脱氧核苷酸转移酶（TdT）介导的dUTP缺口末端标记（TUNEL）染色和α-SMA阳性细胞的数量，并在第18天后迅速减少双阳性细胞。总体而言，当前研究确定bFGF是体内减少肌成纤维细胞面积的有效刺激因子，推测这是由于其对α-SMA表达下调以及对肌成纤维细胞凋亡的快速诱导作用。
