PROGRESSIVE DEVELOPMENT OF THE RAT OSTEOBLAST PHENOTYPE INVITRO - RECIPROCAL RELATIONSHIPS IN EXPRESSION OF GENES ASSOCIATED WITH OSTEOBLAST PROLIFERATION AND DIFFERENTIATION DURING FORMATION OF THE BONE EXTRACELLULAR-MATRIX
PROGRESSIVE DEVELOPMENT OF THE RAT OSTEOBLAST PHENOTYPE INVITRO - RECIPROCAL RELATIONSHIPS IN EXPRESSION OF GENES ASSOCIATED WITH OSTEOBLAST PROLIFERATION AND DIFFERENTIATION DURING FORMATION OF THE BONE EXTRACELLULAR-MATRIX
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DOI：
10.1002/jcp.1041430304
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发表时间：
1990-06-01
影响因子：
5.6
通讯作者：
STEIN, GS
中科院分区：
文献类型：
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作者：
OWEN, TA;ARONOW, M;STEIN, GS
通过放射自显影、组织化学、生物化学和成骨细胞生长和表型基因的mRNA测定，在胎儿颅骨来源的成骨细胞的原代二倍体培养物中研究了细胞增殖与表征与骨细胞分化相关的发育序列的基因的时间表达的关系。基因表达的改变定义了一个发育序列，该序列具有1）三个主要时期：增殖、细胞外基质成熟和矿化;和2）两个限制点，细胞可以进展到这两个限制点，但在没有进一步信号的情况下不能通过-第一个限制点是当增殖被下调并且诱导与细胞外基质成熟相关的基因表达时，第二个限制点是当矿化发生时。最初，活跃增殖的细胞，表达细胞周期和细胞生长调节基因，产生纤连蛋白/I型胶原细胞外基质。增殖活性的下降和随后与基质成熟和矿化相关的基因的诱导之间的相互和功能性耦合关系由以下支持：1）事件的时间顺序，其中在增殖期之后立即存在碱性磷酸酶的增强表达，并且随后在矿化开始时骨钙蛋白和骨桥蛋白的增加表达; 2）当增殖被羟基脲抑制时，成骨细胞表型标志物碱性磷酸酶和骨桥蛋白的特定子集的表达增加;和3）作为抗坏血酸诱导的胶原沉积的函数的成骨细胞标志物的表达水平的提高，这表明细胞外基质有助于增殖的停止和成骨细胞表型的发育。
The relationship of cell proliferation to the temporal expression of genes characterizing a developmental sequence associated with bone cell differentiation was examined in primary diploid cultures of fetal calvarial derived osteoblasts by the combined use of autoradiography, histochemistry, biochemistry, and mRNA assays of osteoblast cell growth and phenotypic genes. Modifications in gene expression define a developmental sequence that has 1) three principle periods.sbd.proliferation, extracellular matrix maturation, and mineralization.sbd.and 2) two restriction points to which the cells can progress but cannot pass without further signals-the first when proliferation is down-regulated and gene expression associated with extracellular matrix maturation is induced, and the second when mineralization occurs. Initially, actively proliferating cells, expressing cell cycle- and cell growth-regulated genes, produce a fibronectin/type I collagen extracellular matrix. A reciprocal and functionally coupled relationship between the decline in proliferative activity and the subsequent induction of genes associated with matrix maturation and mineralization is supported by 1) a temporal sequence of events in which there is an enhanced expression of alkaline phosphatase immediately following the proliferative period, and later, an increased expression of osteocalcin and osteopontin at the onset of mineralization; 2) increased expression of a specific subset of osteoblast phenotype markers, alkaline phosphatase and osteopontin, when proliferation is inhibited by hydroxyurea; and 3) enhanced levels of expression of the osteoblast markers as a function of ascorbic acid-induced collagen deposition, suggesting that the extracellular matrix contributes to both the shutdown of proliferation and the development of the osteoblast phenotype.