Studies on the age-related decline in the migration of human skin fibroblasts into a denuded area in a cell monolayr

人皮肤成纤维细胞的迁移随着体内和体外（供体年龄）的衰老而减少。为了了解年龄相关衰退的机制，我们试图确定调节细胞迁移的因素，并证明人类胎儿皮肤成纤维细胞的迁移是由自身产生的bFGF和胶原蛋白（胎儿表型）刺激的，而成人供体皮肤成纤维细胞的迁移是由PDGF和胶原蛋白（成人表型）刺激的。胎儿-成人表型转变发生在出生前，因为PDGF刺激了新生儿成纤维细胞的迁移。为了发现两种表型的差异，我们研究了FGF受体（FGFR） mRNA在胎儿皮肤成纤维细胞中的表达是否与成人和老年皮肤成纤维细胞中的表达不同。Northern blot分析显示，在所有检测的人皮肤成纤维细胞中均检测到FGFR-1 mRNA，而未检测到其他三种FGFR mRNA（2、3、4型）。人皮肤成纤维细胞中FGFR-1 mRNA的表达似乎与供体年龄呈负相关，这表明胎儿-成人表型转变不能用FGFR来解释。其次，研究了细胞迁移与胶原合成的关系。干扰素- β抑制人胎儿皮肤成纤维细胞的迁移。抑制是特异性的，因为中和的抗干扰素- β抗体逆转了干扰素- β诱导的细胞迁移抑制。在100 IU/ml干扰素- β浓度下，胶原合成受到抑制，成纤维细胞的迁移受到抑制。另一方面，人成人血清抑制人胎儿皮肤成纤维细胞迁移和胶原合成。这些结果表明，细胞迁移的抑制与胶原合成的减少之间存在很强的相关性，表明皮肤成纤维细胞迁移的年龄相关性下降主要是由于胶原蛋白。

The migration of human skin fibroblasts declined with in vitro and in vivo(donor age) aging. To understand the mechanism of the age-related decline, we tried to determine the factors which regulate cell migration and demonstrated that the migration of human fetal skin fibroblasts was stimulated by bFGF,which was produced by themselves, and collagen (fetal phenotype), whereas the migration of adult-donor skin fibroblasts was stimulated by PDGF and collagen (adult phenotype). The fetal-adult phenotype transition occurred before birth because newborn fibroblast migration was stimulated by PDGF.To find the difference of the two phenotypes, whether FGF receptor (FGFR) mRNA expression in fetal skin fibroblasts differs from those in adult and old skin fibroblasts was studied. Northern blot analysis demonstrated that FGFR-1 mRNA was detected in all human skin fibroblasts examined and the other three FGFR mRNA (type2,3,4) were not detected. The expression of FGFR-1 mRNA in human skin fibroblasts seemed to decrease inversely to donor age, suggesting that fetal-adult phenotype transition is not explained by FGFR.Next, the relationship between cell migration and collagen synthesis was investigated.Interferon-betasuppressed the migration of human fetal skin fibroblasts. The inhibition was specific because neutralizing anti-interferon-betaantibody reversed the inhibition of cell migration induced by interferon-beta.Collagen synthesis was inhibited at 100 IU/ml interferon-beta, at the concentration of which fibroblast migration was suppressed. On the other hand, human adult serum suppressed human fetal skin fibroblast migration as well as collagen synthesis. These results indicate the strong correlation between the inhibition of cell migration and the decrease of collagen synthesis, suggesting that age-related decline in skin fibroblast migration is largely due to collagen.