Colwell Amy S, Krummel Thomas M, Longaker Michael T, Lorenz H Peter
Department of Surgery, Division of Plastic Surgery, Children's Surgical Research Program, Tissue Regeneration Laboratory, Stanford, Calif. 94305-5148, USA.
Plast Reconstr Surg. 2006 Jun;117(7):2277-83. doi: 10.1097/01.prs.0000224299.16523.76.
The scarless fetal skin-healing mechanism is mediated in part by the fibroblast and involves differential expression of transforming growth factor (TGF)-beta isoforms 1 and 3. The authors hypothesized that fetal and adult fibroblasts respond differently to TGF-beta isoform-specific stimulation, which may influence whether wounds scar. Connective tissue growth factor (CTGF), Smad3, and Smad7 are TGF-beta target genes. Expression of these targets was quantitated after TGF-beta1 and -beta3 stimulation of fetal and adult fibroblasts.
Primary mouse fibroblast cultures at gestational day 16.5 (E17), 18.5 (E19), and 6 weeks (adult) were stimulated with TGF-beta1 or TGF-beta3. Quantitative polymerase chain reaction was performed for CTGF, Smad3, and Smad7 expression.
CTGF was reduced four-fold in E17 and E19 compared with adult fibroblasts (p < 0.005). After TGF-beta1 stimulation, CTGF expression increased more than 60-fold in both E17 and E19 (p < 0.01), which was three-fold greater than that in adult fibroblasts (p < 0.005). TGF-beta3 induced more than 70-fold, 50-fold, and 20-fold increases in CTGF expression in E17, E19, and adult fibroblasts, respectively (p < 0.01 for each). Both TGF-beta1 and -beta3 decreased Smad3 expression and increased Smad7 expression in each fibroblast type, suggesting that intact TGF-beta-mediated signaling pathways were present.
Fetal (E17 and E19) fibroblasts have lower CTGF expression compared with adult fibroblasts. However, fetal fibroblasts have larger increases in CTGF expression after TGF-beta1 or -beta3 stimulation. Fetal and adult mouse fibroblasts have similar TGF-beta1 and TGF-beta3 transcriptional regulation of Smad3 and Smad7. This suggests that scarless healing is likely not mediated by different Smad-dependent transcriptional responses to TGF-beta isoforms in the fetal E17 fibroblast.
胎儿皮肤无瘢痕愈合机制部分由成纤维细胞介导，涉及转化生长因子（TGF）-β1和β3亚型的差异表达。作者推测胎儿和成体成纤维细胞对TGF-β亚型特异性刺激的反应不同，这可能影响伤口是否形成瘢痕。结缔组织生长因子（CTGF）、Smad3和Smad7是TGF-β的靶基因。在TGF-β1和-β3刺激胎儿和成体成纤维细胞后，对这些靶标的表达进行定量。
用TGF-β1或TGF-β3刺激妊娠第16.5天（E17）、18.5天（E19）和6周（成体）的原代小鼠成纤维细胞培养物。对CTGF、Smad3和Smad7的表达进行定量聚合酶链反应。
与成体成纤维细胞相比，E17和E19中的CTGF降低了四倍（p<0.005）。在TGF-β1刺激后，E17和E19中的CTGF表达均增加了60倍以上（p<0.01），这比成体成纤维细胞中的增加了三倍（p<0.005）。TGF-β3分别使E17、E19和成体成纤维细胞中的CTGF表达增加了70倍以上、50倍和20倍（每组p<0.01）。TGF-β1和-β3均降低了每种成纤维细胞类型中Smad3的表达并增加了Smad7的表达，表明存在完整的TGF-β介导的信号通路。
与成体成纤维细胞相比，胎儿（E17和E19）成纤维细胞的CTGF表达较低。然而，胎儿成纤维细胞在TGF-β1或-β3刺激后CTGF表达增加幅度更大。胎儿和成体小鼠成纤维细胞对Smad3和Smad7具有相似的TGF-β1和-β3转录调控。这表明胎儿E17成纤维细胞中无瘢痕愈合可能不是由对TGF-β亚型不同的Smad依赖性转录反应介导的。
