Interactions between endogeneous lectins and fucosylated oligosaccharides in megakaryocyte-dependent fibroblast growth of the normal bone marrow.
In order to elucidate the involvement of adhesion mechanisms in the process of megakaryocyte-dependent fibroblast growth, we applied BSA-coupled polymers of glucose, galactose, fucose, mannose, and several lectins (AAA, LCA, LTA, UEA-I) to cocultures of CD61 -positive (CD61+)/MACS-enriched megakaryocytes and human bone marrow fibroblasts. Fibroblast monocultures served as controls. After 6 days, glucose, as well as galactose-treated cultures showed a significant reduction of fibroblast growth in cocultures and fibroblast monocultures. In contrast, application of mannose caused no reducing effect on fibroblast numbers. Administration of fucose, AAA, LTA or UEA-I revealed a strong impairment of fibroblast growth in the megakaryocyte-fibroblast cocultures. Adhesion experiments using MACS-enriched, fluorescein-labelled megakaryocytes cultured in the presence of carbohydrates and lectins on a near-confluent layer of fibroblasts were additionally performed. Following fucose-BSA, alpha Fuc-1,2Gal beta-HSA or UEA-I treatment a significant reduction of megakaryocyte adhesion to the fibroblast layer could be observed. In the case of AAA a weak impairment of megakaryocyte adhesion could be noticed. Selective pretreatment of either fibroblasts or megakaryocytes with fucose-BSA or alpha Fuc-1,2Gal beta-HSA was consistent with the finding of a prominent involvement of fucosylated residues located on megakaryocytes in this interaction. In conclusion, our studies are in keeping with the assumption that fucosylated and fucose-binding structures are playing a key role in adhesion mechanisms between megakaryocytes and fibroblasts and thus influence significantly the megakaryocyte-dependent growth of bone marrow fibroblasts.
Schmitz
B
B
Institute of Pathology, University of Cologne, Germany.
Thiele
J
J
Otto
F
F
Theile-Ochel
S
S
Heedt
T
T
Zensen
U
U
Baldus
S E
SE
Wickenhauser
C
C
Fischer
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001854:Bone Marrow Cells; D002448:Cell Adhesion; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D037102:Lectins / Q000494:pharmacology*; D008297:Male; D008533:Megakaryocytes / Q000502:physiology*; D008875:Middle Aged; D009844:Oligosaccharides / Q000494:pharmacology*
D037102:Lectins; D009844:Oligosaccharides