Distinct proliferative and differentiated stages of murine MC3T3-E1 cells in culture: An in vitro model of osteoblast development

作者：L. Darryl Quarles, Daniel A. Yohay, Laura W. Lever, R. Caton, RICHARD J. WENSTRUP · 发表于：Journal of Bone and Mineral Research · 年份：1992 · DOI：10.1002/jbmr.5650070613 · 被引用次数：994 · 研究领域：Bone Metabolism and Diseases、Bone and Dental Protein Studies、Bone health and treatments

We examine clonal murine calvarial MC3T3-E1 cells to determine if they exhibit a developmental sequence similar to osteoblasts in bone tissue, namely, proliferation of undifferentiated osteoblast precursors followed by postmitotic expression of differentiated osteoblast phenotype. During the initial phase of developmental (days 1-9 of culture), MC3T3-E1 cells actively replicate, as evidenced by the high rates of DNA synthesis and progressive increase in cell number, but maintain a fusiform appearance, fail to express alkaline phosphatase, and do not accumulate mineralized extracellular collagenous matrix, consistent with immature osteoblasts. By day 9 the cultures display cuboidal morphology, attain confluence, and undergo growth arrest. Downregulation of replication is associated with expression of osteoblast functions, including production of alkaline phosphatase, processing of procollagens to collagens, and incremental deposition of a collagenous extracellular matrix. Mineralization of extracellular matrix, which begins approximately 16 days after culture, marks the final phase of osteoblast phenotypic development. Expression of alkaline phosphatase and mineralization is time but not density dependent. Type I collagen synthesis and collagen accumulation are uncoupled in the developing osteoblast. Although collagen synthesis and message expression peaks at day 3 in immature cells, extracellular matrix accumulation is minimal. Instead, matrix accumulates maximally after 7 da...