Effects of interferon alpha on human osteoprogenitor cell growth and differentiation in vitro

Abstract

The specific effects of interferon alpha (IFN␣), on the differentiation pathways of human osteogenic cells are not known. The aim of this study was to investigate possible effects of IFN␣ on osteogenic development by investigating cell differentiation, colony formation (colony forming unit-fibroblastic, CFU-F), cell proliferation, and gene expression, in particular bone morphogenetic protein (BMP) expression, of human bone marrow osteoprogenitor cells. Human bone marrow fibroblasts were cultured with or without the addition of IFN␣ (5-1,000 IU/ml) in the presence and absence of dexamethasone (10 nM) and ascorbate (100 µM), which are agents known to affect osteogenic differentiation. IFN␣ produced a significant dose-dependent inhibition of cell proliferation and alkaline phosphatase specific activity at concentrations as low as 50 IU/ml. IFN␣ (50-1,000 IU/ml) inhibited the stimulation of alkaline phosphatase specific activity induced by ascorbate and dexamethasone. Examination of CFU-F showed dose-and time-dependent inhibitions of colony formation and reductions in both colony size and alkaline phosphatase-positive CFU-F colonies particularly at earlier times. Reactivity with an antibody specific for osteoprogenitors (HOP-26), was reduced in IFN␣-treated cultures. Northern blot analysis showed a significant dose-dependent up-regulation of BMP-2 mRNA, estrogen receptor alpha mRNA and osteocalcin mRNA expression in ascorbate/dexamethasone cultures. In contrast, IFN␣ significantly inhibited BMP-2 mRNA expression in the absence of ascorbate and dexamethasone. In conclusion, IFN␣ inhibits human osteoprogenitor cell proliferation, CFU-F formation, HOP-26 expression, and alkaline phosphatase specific activity and modulates BMP-2 gene expression. These results suggest a role for IFN␣ in local bone turnover through the specific and direct modulation of osteoprogenitor proliferation and differentiation.

Imprinting of the human L3MBTL gene, a polycomb family member located in a region of chromosome 20 deleted in human myeloid malignancies

“…Total RNA was extracted from cells by using TRI Reagent according to the manufacturer's instructions (Sigma-Aldrich). Ϫ cells were collected after isolation of CD34 ϩ cells as described above and were immediately cultured as described (20). After 4 weeks, the adherent bone marrow mesenchymal cells were harvested, and flow cytometry by using FITC-CD45 (marker for all hematopoietic lineages) and PE-CD105 (marker for bone marrow stromal mesenchymal cells) showed them to be 99.5% CD105 ϩ ͞CD45…”

A sub-population of high proliferative potential-quiescent human mesenchymal stem cells is under the reversible control of interferon α/β

“…35 The aim of the present study was to address the question of a possible involvement of type I interferons (IFN), as negative regulators of the cell cycle of human bone marrow-derived mesenchymal precursor cells, as IFNa has been described as a potent inhibitor of marrow stromal cells. [36][37][38] As a tool to block IFN signalling, we previously produced and characterized a neutralizing monoclonal antibody, 64G12, directed against IFNAR1, one of the two polypeptide chains constituting the receptor for IFNa, b and o. 39,40 The anti-IFNAR1 antibody, 64G12, has been shown to neutralize all human type I IFNs.…”

Bone Marrow Composition and Bone Microarchitecture and Turnover in Blacks and Whites

“…The positive correlations between bone marrow cellularity and static bone turnover variables obtained when all 98 cases were analyzed together suggest an interaction between bone turnover and marrow cellularity. This interaction has been shown to be mediated by growth factors and cytokines 3 , 15–19 . These substances control in particular the differentiation of bipotential stromal cells to either osteoblasts or adipocytes.…”