HUMAN OSTEOGENIC PROTEIN-1 INDUCES BOTH CHONDROBLASTIC AND OSTEOBLASTIC DIFFERENTIATION OF OSTEOPROGENITOR CELLS DERIVED FROM NEWBORN RAT CALVARIA
HUMAN OSTEOGENIC PROTEIN-1 INDUCES BOTH CHONDROBLASTIC AND OSTEOBLASTIC DIFFERENTIATION OF OSTEOPROGENITOR CELLS DERIVED FROM NEWBORN RAT CALVARIA
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DOI：
10.1083/jcb.123.4.921
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发表时间：
1993-11-01
影响因子：
7.8
通讯作者：
HAUSCHKA, PV
中科院分区：
文献类型：
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作者：
ASAHINA, I;SAMPATH, TK;HAUSCHKA, PV
成骨蛋白-1（OP-1）是TGF-β超家族的成员，在体内诱导皮下部位的软骨内骨形成，并在体外刺激成骨细胞表型表达。新生大鼠颅骨细胞的原代培养物包含一系列成骨表型，从未分化的间充质骨祖细胞到甲状旁腺激素（PTH）反应性成骨细胞。我们研究了重组人成骨蛋白-1处理该细胞群是否能在体外诱导软骨形成。成软骨细胞与成骨细胞分化的标志物包括pH 1时的阿辛蓝染色、碱性磷酸酶特异性活性、骨钙素放射免疫测定和胶原mRNA的表达。用4-100 ng OP-1/ml处理6 d（培养第1-7天）导致阿辛蓝染色强度和碱性磷酸酶活性的剂量依赖性增加（40 ng/ml时分别为4.7倍和3.4倍），而骨钙素的产生减少了两倍。第3天，出现了圆形的、可触知的、阿辛蓝染色的细胞簇，直到第7天数量增加，然后变得肥大，逐渐变得不那么明显。组织化学上，第7天的集群与高碱性磷酸酶活性，并成为矿化。II型和IX型胶原蛋白的mRNA转录增加OP-1，峰值在第4天，而X型胶原蛋白的mRNA仅在OP-1处理的培养物中的第7天可检测到。延迟OP-1暴露直到汇合（第7天）放大了正常成骨细胞表型的表达并加速其发育成熟。相比之下，在第1天开始的早期OP-1治疗强烈放大成软骨细胞分化。在相同的方案中，单独的0.01-40 ng/ml的TGF-β 1不能诱导任何肥大的软骨细胞，并且与OP-1组合时，TGF-β 1阻断OP-1依赖性软骨诱导。OP-1被认为作用于原始骨祖细胞的亚群以诱导软骨内骨化，但似乎没有将定向成骨细胞逆转为软骨细胞表型。
Osteogenetic protein-1 (OP-1), a member of the TGF-beta superfamily, induces endochondral bone formation at subcutaneous sites in vivo and stimulates osteoblastic phenotypic expression in vitro. Primary cultures of newborn rat calvarial cells contain a spectrum of osteogenic phenotypes ranging from undifferentiated mesenchymal osteoprogenitor cells to parathyroid hormone (PTH)-responsive osteoblasts. We examined whether treatment of this cell population with recombinant human osteogenic protein-1 could induce chondrogenesis in vitro. Markers of chondroblastic versus osteoblastic differentiation included alcian blue staining at pH 1, alkaline phosphatase-specific activity, osteocalcin radioimmunoassay, and expression of collagen mRNAs. 6 d of treatment (culture days 1-7) with 4-100 ng OP-1/ml caused dose-dependent increases in alcian blue staining intensity and alkaline phosphatase activity (4.7- and 3.4-fold, respectively, at 40 ng/ml), while osteocalcin production decreased twofold. Clusters of round, refractile, alcian blue-stained cells appeared by day 3, increased in number until day 7, and then became hypertrophic and gradually became less distinct. Histochemically, the day 7 clusters were associated with high alkaline phosphatase activity and became mineralized. mRNA transcripts for collagen types II and IX were increased by OP-1, peaking at day 4, while type X collagen mRNA was detectable only on day 7 in OP-1-treated cultures. Delay of OP-1 exposure until confluence (day 7) amplifies expression of the normal osteoblastic phenotype and accelerates its developmental maturation. In contrast, early OP-1 treatment commencing on day 1 strongly amplifies chondroblastic differentiation. In the same protocol, TGF-beta1 alone at 0.01-40 ng/ml fails to induce any hypertrophic chondrocytes, and in combination with OP-1, TGF-beta1 blocks OP-1-dependent chondroinduction. OP-1 is believed to act on a subpopulation of primitive osteoprogenitor cells to induce endochondral ossification, but does not appear to reverse committed osteoblasts to the chondrocyte phenotype.