Over-sulfated chondroitin sulfate derivatives induce osteogenic differentiation of hMSC independent of BMP-2 and TGF-β1 signalling.
Natural glycosaminoglycans (GAGs) and chemically modified GAG derivatives are known to support osteogenic differentiation of mesenchymal stromal cells (MSC). This effect has mainly been described to be mediated by increasing the effectiveness of bone anabolic growth factors such as bone morphogenetic proteins (BMPs) due to the binding and presentation of the growth factor or by modulating its signal transduction pathway. In the present study, the influence of chondroitin sulfate (CS) and two chemically over-sulfated CS derivatives on osteogenic differentiation of human mesenchymal stromal cells (hMSC) and on BMP-2 and transforming growth factor β1 (TGF-β1) signalling was investigated. Over-sulfated CS derivatives induced an increase of tissue non-specific alkaline phosphatase (TNAP) activity and calcium deposition, whereas collagen synthesis was slightly decreased. The BMP-2-induced Smad1/5 activation was inhibited in the presence of over-sulfated CS derivatives leading to a loss of BMP-2-induced TNAP activity and calcium deposition. In contrast, the TGF-β1-induced activation of Smad2/3 and collagen synthesis were not affected by the over-sulfated CS derivatives. BMP-2 and TGF-β1 did not activate the extracellular signal-regulated kinase 1/2 or mitogen-activated protein kinase p38 in hMSC. These data suggest that over-sulfated CS derivatives themselves are able to induce osteogenic differentiation, probably independent of BMP-2 and TGF-β1 signalling, and offer therefore an interesting approach for the improvement of bone healing.
Institute of Physiological Chemistry, Technische Universität Dresden, Dresden, Germany.
Marianne
M
Büttner
Stephanie
S
Möller
Mario
M
Keller
Daniel
D
Huster
Jürgen
J
Schiller
Matthias
M
Schnabelrauch
Peter
P
Dieter
Ute
U
Hempel
D000328:Adult; D000469:Alkaline Phosphatase / Q000096:biosynthesis; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000378:metabolism / Q000494:pharmacology*; D003094:Collagen / Q000096:biosynthesis; D005260:Female; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000187:drug effects*; D010012:Osteogenesis / Q000187:drug effects*; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D051785:Smad Proteins / Q000096:biosynthesis; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1; D002809:Chondroitin Sulfates; D003094:Collagen; D011494:Protein Kinases; D000469:Alkaline Phosphatase; D002118:Calcium