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外和体内(供体年龄)年龄的增长而下降。为了了解年龄相关性下降的机制，我们试图确定调节细胞迁移的因素，并证明人胚胎皮肤成纤维细胞的迁移受到自身产生的bFGF和胶原(胎儿表型)的刺激，而成人供体皮肤成纤维细胞的迁移则受到PDGF和胶原(成人表型)的刺激。胎儿-成人成纤维细胞的表型转化在出生前就已经发生了，这是由于PDGFF刺激了新生成纤维细胞的迁移，为了找出这两种表型的差异，我们研究了胎儿皮肤成纤维细胞中成纤维细胞生长因子受体(FGFR)的表达是否与成人和老年皮肤成纤维细胞的表达不同。Northern印迹分析表明，所有受试者皮肤成纤维细胞中均检测到FGFR-1mRNA，其他3种FGFR(2，3，4型)均未检测到。人皮肤成纤维细胞中FGFR-1mRNA的表达似乎与供者年龄成反比，提示FGFR不能解释胎儿向成人的表型转换。其次，研究了细胞迁移与胶原合成的关系。干扰素-β抑制了人胚胎皮肤成纤维细胞的迁移。这种抑制是特异性的，因为中和抗干扰素-β抗体逆转了干扰素-β对细胞迁移的抑制。当干扰素-β浓度为100IU/ml时，胶原合成受到抑制，当干扰素-β浓度达到100IU/ml时，成纤维细胞的迁移受到抑制。另一方面，成人血清抑制人胎儿皮肤成纤维细胞的迁移和胶原合成。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，提示皮肤成纤维细胞迁移的年龄相关性下降主要是由于胶原。

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.