Basic fibroblast growth factor (bFGF) and its receptor expression (bek and flg) In bone marrow stroma of murine AIDS.
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.
Tse
Kam-Fai
KF
Hematology/Oncology Division, Laboratory of Experimental Immunohematopoiesis and Developmental Therapeutics, Department of Internal Medicine,University of Kentucky, Lexington, KY 40536-0084, USA.
Inayat
Mohammed S
MS
Morrow
Jennifer K
JK
DellaPuca
Richard
R
Hughes
Nedda K
NK
Gallicchio
Vincent S
VS
D000818:Animals; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000378:metabolism / Q000821:virology*; D002460:Cell Line; D003114:Colony-Forming Units Assay; D016222:Fibroblast Growth Factor 2 / Q000032:analysis / Q000235:genetics* / Q000494:pharmacology; D000091344:Filaggrin Proteins; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects; D009052:Leukemia Virus, Murine / Q000472:pathogenicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D016183:Murine Acquired Immunodeficiency Syndrome / Q000821:virology; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D051497:Receptor, Fibroblast Growth Factor, Type 2; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000378:metabolism / Q000821:virology*; D014158:Transcription, Genetic
C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D012333:RNA, Messenger; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; C496354:Fgfr2 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051497:Receptor, Fibroblast Growth Factor, Type 2