• Journal of Life Science
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• v.16 no.2 s.75
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• pp.231-239
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• 2006

Human mesenchymal stem cells (hMSCs) in bone marrow (BM) can be induced to differentiate into a variety of mesenchymal tissues, including adipocytes, osteoblasts and chondroblasts, under the influence of certain growth or environmental factors. In this study, we analyzed the differentiation process and the associated gene expression profiles inherent to the process by which hMSCs differentiate into osteoblasts. We conducted a comparison of gene expression profiles of the normal human BM MSCs, using human 8K cDNA microarray, incubated in media containing either a combination of $\beta$-glycerol phosphate, L-ascorbic acid, and dexamethasone, or in medium lacking these osteogenic supplements. During the osteoblastic differentiation process, 36 genes were determined to be up-regulated, and 59 genes were shown to be down-regulated. Osteoprotegerin, LRP5, and metallothionein 2A, all of which are associated with the osteogenetic process, were up-regulated, and genes associated with the differentiation of MSCs into other lineages, including muscle, adipose tissue and vascular structure were down-regulated. The set of differentially expressed genes reported in this work should contribute to our current understanding of the processes inherent to the differentiation of MSCs into osteoblasts.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.447-463
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• 2007

Periodontal ligament (PDL) cells have been known as multipotential cells, and as playing an important rolesin periodontal regeneration. The PDL cells are composed of heterogeneous cell populations which have the capacity to differentiate into either cementoblasts or osteoblasts, depending on needs and conditions. Therefore, PDL cells have the capacity to produce mineralized nodules in vitro in mineralization medium which include ascorbic acid, ${\beta}$-glycerophosphate and dexamethasone. In spite of these well-known osteoblast like properties of PDL cells, very little is known about the molecules involved in the formation of the mineralized nodules in the PDL cells. In the present study, we analysed gene-expression profiles during the mineralization process of cultured PDL cells by means of a cDNA microarray consisting of 3063 genes. Nodules of mineralized matrix were strongly stained with alizarin red S on the PDL cells cultured in the media with mineralization supplements. Among 3,063 genes analyzed, 35 were up-regulated more than two-fold at one or more time points in cells that developed matrix mineralization nodules, and 38 were down-regulated to less than half their normal level of expression. In accord with the morphological change we observed, several genes related to calcium-related or mineral metabolism were induced in PDL cells during osteogenesis, such as IGF-II and IGFBP-2. Proteogycan 1, fibulin-5, keratin 5, ,${\beta}$-actin, ${\alpha}$-smooth muscle actin and capping protein, and cytoskeleton and extracellular matrix proteins were up-regulated during mineralization. Several genes encoding proteins related to apoptosis weredifferentially expressed in PDL cells cultured in the medium containing mineralization supplements. Dkk-I and Nip3, which are apoptosis-inducing agents, were up-regulated, and Btf and TAXlBP1, which have an anti-apoptosis activity, were down-regulated during mineralization. Also periostin and S100 calciumbinding protein A4 were down-regulated during mineralization.