Basic fibroblast growth factor (bFGF) and its receptor expression ( bek and flg) In bone marrow stroma of murine AIDS

• Published in: Virus research 2004-05, Vol.101 (2), p.175-184
• Main Authors: Tse, Kam-Fai, Inayat, Mohammed S, Morrow, Jennifer K, DellaPuca, Richard, Hughes, Nedda K, Gallicchio, Vincent S
• Format: Article
• Language: English
• Subjects: Animals; bFGF; Blotting, Western; Bone Marrow Cells - metabolism; Bone Marrow Cells - virology; Cell Line; Colony-Forming Units Assay; Fibroblast Growth Factor 2 - analysis; Fibroblast Growth Factor 2 - genetics; Fibroblast Growth Factor 2 - pharmacology; Gene Expression; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - drug effects; Leukemia Virus, Murine - pathogenicity; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Murine Acquired Immunodeficiency Syndrome - virology; Receptor expression; Receptor Protein-Tyrosine Kinases - genetics; Receptor, Fibroblast Growth Factor, Type 2; Receptors, Fibroblast Growth Factor - genetics; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - analysis; Stromal cells; Stromal Cells - metabolism; Stromal Cells - virology; Transcription, Genetic; Virus infection
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2004.01.007

Murine acquired immunodeficiency disease (MAIDS) induced by LPBM5 MuLV is characterized by a late-stage lymphoma and hematopoietic cytopenias similar to those observed in human AIDS. The pathogenesis of MAIDS-related lymphoma/cytopenia is unknown but it has been postulated to involve a defective marrow microenvironment or stroma. The basic Fibroblast Growth Factor (bFGF) of stromal origin is an important stimulator for hematopoietic progenitors of several lineages. Long-term bone marrow cultures (LTBMCs) were established and pure stromal cell cultures were used for in vitro infection hematopoietic reconstitution studies. Reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze bFGF gene expression in stromal cells derived from either viral-infected marrow or uninfected marrow. RT-PCR analysis showed a 40% reduction in the expression of bFGF transcript expression from viral-infected stromal cells, however, the levels of bek and flg bFGF receptors remained unchanged indicating virus-infection only inhibited bFGF gene expression in stromal cells. Viral infection was associated with a progressive decrease in bFGF transcript expression 35% of control at day 7, 50% of control at day 14 and 60% of control at day 21 compared to the mock-infected cultures. In addition, for bek and flg the transcript expression in, in vitro-infected primary cultures were comparable to the mock-infected cultures and remained essentially unchanged throughout culture period. Western blot analysis revealed viral-infected stromal cells produced a 45% decrease in bFGF protein production. Reduction of bFGF protein was confirmed by indirect immunofluorescent staining. We report MuLV infection reduces bFGF transcript expression but not its surface-receptors ( bek and flg) in infected stromal cells. Impaired hematopoiesis consistently exhibited from MuLV-infected stromal cultures was restored by exogenous bFGF; therefore, bFGF was responsible in restoration of normal marrow stromal support function. These results suggest a role for bFGF deficiency in the pathogenesis of MAIDS-related marrow failure.