Osteoblastic gene expression during adipogenesis in hematopoietic supporting murine bone marrow stromal cells

Abstract

A growing body of data suggests that the bone marrow stroma contains a population of pluripotent cells capable of differentiating into adipocytes, osteoblasts, and lymphohematopoietic supporting cells. In this work, the murine stromal cell lines BMS2 and +/+ 2.4 have been examined as preadipocytes and adipocytes for evidence of osteoblastic gene expression. Adipocyte differentiation has been quantitated using fluorescence activated cell sorting. Within 7-10 days of adipocyte induction by treatment with glucocorticoids, indomethacin, and methylisobutylxanthine, between 40% to 50% of the cells contain lipid vacuoles and exhibit a characteristic adipocyte morphology. Based on immunocytochemistry, both the adipocytes and preadipocytes express a number of osteoblastic markers; these include alkaline phosphatase, osteopontin, collagen (I, III), bone sialoprotein II, and fibronectin. Based on biochemical assays, the level of alkaline phosphatase expression is not significantly different between preadipocyte and adipocyte cells. However, unlike rat cell lines, dexamethasone exposure causes a dose-dependent decrease in enzyme activity. The steady-state mRNA levels of the osteoblast associated genes varies during the process of adiopogenesis. The relative level of collagen I and collagen III mRNA is lower in adipocyte-induced cells when compared to the uninduced controls. Osteocalcin mRNA is detected in preadipocytes but absent in adipocytes. These data indicate that osteoblastic gene expression is detected in cells capable of undergoing adipocyte differentiation, consistent with the hypothesis that these cell lineages are interrelated.

Pleiotropic effects of the steroid hormone 1,25-dihydroxyvitamin D3 on the recruitment of mesenchymal lineage progenitors in fetal rat calvaria cell populations

“…These cell lineages co-exist under physiological and pathological conditions in bone, bone marrow and some other tissue compartments (Caplan 1991, Dorheim et al 1993, Friedenstein 1995, Aubin 1998), but a comprehensive analysis of the ability of 1,25(OH) 2 D 3 simultaneously to recruit or alter the fate of multiple mesenchymal lineage precursors has not previously been carried out. By using gene expression analysis of single cell-derived colonies, we have achieved new insights into the types of progenitors present in RC cell populations and the ability of 1,25(OH) 2 D 3 to alter their fate choices.…”

Age‐ and gender‐related changes in the cellularity of human bone marrow and the prevalence of osteoblastic progenitors

“…It should be noted that this human study differs significantly from previous animal studies, which obtained bone or bone marrow cells by open irrigation of explanted bones [3,5,[8][9][10]13,14,22,24] or by enzymatic digestion [15]. Samples in the current study were harvested by aspiration, which is a much less vigorous means of dislodging cells.…”

Differentiation plasticity of chondrocytes derived from mouse embryonic stem cells

“…Specimens were then incubated for 1 hour with the first antibody in a humidified chamber at 37°C. The following monoclonal antibodies (mAbs) diluted in PBS were obtained from the Developmental Studies Hybridoma Bank, University of Iowa, USA (designation of the mAb, the dilution used and a reference are given in brackets): Collagen II [II-II-6B3, 1:20 (Linsenmayer and Hendrix, 1980)], osteopontin [MPIIIB101,1:10 (Dorheim et al, 1993)], collagen X [X-AC9, 1:20 (Schmid and Linsenmayer, 1985)] and bone sialoprotein I + II [WVID1(9C5), 1:10 (Dorheim et al, 1993)]. To detect cytokeratins, anti-pan cytokeratin, diluted 1:100 (Sigma), for immunostaining of sarcomeric α-actinin mAb EA-53 (Sigma) diluted 1:20 and for collagen I, a polyclonal antiserum (Chemicon, Temecula, CA) diluted 1:100 were used.…”