Kawazoe Yumi, Katoh Shinichi, Onodera Yuichiro, Kohgo Takao, Shindoh Masanobu, Shiba Toshikazu
Regenetiss Inc., 1-9-4, Asahigaoka, Hino, Tokyo 191-0065, Japan.
Int J Biol Sci. 2008 Feb 3;4(1):37-47. doi: 10.7150/ijbs.4.37.
Inorganic polyphosphate [poly(P)] is a biopolymer existing in almost all cells and tissues, although its biological functions in higher eukaryotes have not been completely elucidated. We previously demonstrated that poly(P) enhances the function of fibroblast growth factors (FGFs) by stabilizing them and strengthening the affinity between FGFs and their cell surface receptors. Since FGFs play crucial roles in bone regeneration, we further investigated the effect of poly(P) on the cell differentiation of human stem cells via FGF signaling systems. Human dental pulp cells (HDPCs) isolated from human dental pulp show the characteristics of multipotent mesenchymal stem cells (MSCs). HDPCs secreted FGFs and the proliferation of HDPCs was shown to be enhanced by treatment with poly(P). Cell surface receptor-bound FGF-2 was stably maintained for more than 40 hours in the presence of poly(P). The phosphorylation of ERK1/2 was also enhanced by poly(P). The effect of poly(P) on the osteogenic differentiation of HDPCs and human MSCs (hMSCs) were also investigated. After 5 days of treatment with poly(P), type-I collagen expression of both cell types was enhanced. The C-terminal peptide of type-I collagen was also released at higher levels in poly(P)-treated HDPCs. Microarray analysis showed that expression of matrix metalloproteinase-1 (MMP1), osteopontin (OPN), osteocalcin (OC) and osteoprotegerin was induced in both cell types by poly(P). Furthermore, induced expression of MMP1, OPN and OC genes in both cells was confirmed by real-time PCR. Calcification of both cell types was clearly observed by alizarin red staining following treatment with poly(P). The results suggest that the activation of the FGF signaling pathway by poly(P) induces both proliferation and mineralization of stem cells.
无机多聚磷酸盐[poly(P)]是一种存在于几乎所有细胞和组织中的生物聚合物，尽管其在高等真核生物中的生物学功能尚未完全阐明。我们之前证明，poly(P)通过稳定成纤维细胞生长因子(FGFs)并增强FGFs与其细胞表面受体之间的亲和力来增强其功能。由于FGFs在骨再生中起关键作用，我们进一步研究了poly(P)通过FGF信号系统对人干细胞细胞分化的影响。从人牙髓中分离出的人牙髓细胞(HDPCs)具有多能间充质干细胞(MSCs)的特征。HDPCs分泌FGFs，并且poly(P)处理可增强HDPCs的增殖。在poly(P)存在的情况下，细胞表面受体结合的FGF-2能稳定维持40多个小时。poly(P)还增强了ERK1/2的磷酸化。我们还研究了poly(P)对HDPCs和人MSCs(hMSCs)成骨分化的影响。用poly(P)处理5天后，两种细胞类型的I型胶原蛋白表达均增强。在poly(P)处理的HDPCs中，I型胶原蛋白的C末端肽也以更高的水平释放。微阵列分析表明，poly(P)在两种细胞类型中均诱导了基质金属蛋白酶-1(MMP1)、骨桥蛋白(OPN)、骨钙素(OC)和骨保护素的表达。此外，通过实时PCR证实了两种细胞中MMP1、OPN和OC基因的诱导表达。用poly(P)处理后，通过茜素红染色清楚地观察到两种细胞类型的钙化。结果表明，poly(P)激活FGF信号通路可诱导干细胞的增殖和矿化。
