ABSTRACT
Culturing of suspension fraction of a long-term bone marrow culture derived from tumor necrosis factor (TNF)-deficient mice for 75 days produced cells forming adherent cell strains. The cells of all strains expressed RNA of various stromal differentiating markers in various combinations. The cells of many strains simultaneously expressed genes encoding products characteristic of different differentiation lineages. The derived strains maintained hemopoiesis for 10 weeks. RNA-analysis of gene expression by cells of these strains showed that they express a set of various growth factors and cytokines. It was hypothesized that suspension fraction of long-term bone marrow culture derived from TNF-deficient mice includes immature stromal precursor cells, which were never detected in long-term bone marrow culture derived from wild-type mice.
Subject(s)
Bone Marrow Cells/cytology , Stem Cells/metabolism , Tumor Necrosis Factors/deficiency , Animals , Cell Adhesion , Cells, Cultured , Female , Gene Expression , Hematopoiesis/genetics , Hematopoiesis/physiology , Hematopoietic Stem Cells/metabolism , Male , Mice , Mice, Mutant Strains , RNA, Messenger/analysis , RNA, Messenger/metabolism , Stromal Cells/cytology , Stromal Cells/metabolism , Tumor Necrosis Factors/geneticsABSTRACT
In long-term bone marrow cultures derived from tumor necrosis factor-deficient mice the total cell production and the total duration of hemopoiesis are increased (the latter is comparable with mouse life span). Telomerase activity in cells of nonadherent fraction of long-term bone marrow cultures from tumor necrosis factor-deficient mice increases with time and peaks after 1-year culturing. Karyotyping of nonadherent and adherent cells of long-term bone marrow cultures revealed instability of nonadherent cells and hyperploidy of the stromal sublayer cells, which attested to the presence of a neoplastic transformation. However, cell differentiation is not blocked in long-term bone marrow cultures. The nonadherent fraction of long-term bone marrow cultures from tumor necrosis factor-deficient mice cannot be cultured without exogenous growth factors; in the presence of growth factors the cells proliferate, but cannot be passaged; stromal sublayer cells cannot be passaged as well. Intraperitoneal and intravenous injections of nonadherent cells to recipients with normal and radiation-attenuated immunity induced no tumor growth. Hence, peculiar dynamics of long-term bone marrow cultures from tumor necrosis factor-deficient mice cannot be explained by neoplastic transformation.
