Diverse effects of cyclic AMP variants on osteogenic and adipogenic differentiation of human mesenchymal stromal cells.
Osteogenic differentiation of human mesenchymal stromal cells (hMSCs) may potentially be used in cell-based bone tissue-engineering applications to enhance the bone-forming potential of these cells. Osteogenic differentiation and adipogenic differentiation are thought to be mutually exclusive, and although several signaling pathways and cues that induce osteogenic or adipogenic differentiation, respectively, have been identified, there is no general consensus on how to optimally differentiate hMSCs into the osteogenic lineage. Some pathways have also been reported to be involved in both adipogenic and osteogenic differentiation, as for example, the protein kinase A (PKA) pathway, and the aim of this study was to investigate the role of cAMP/PKA signaling in differentiation of hMSCs in more detail. We show that activation of this pathway with dibutyryl-cAMP results in enhanced alkaline phosphatase expression, whereas another cAMP analog induces adipogenesis in long-term mineralization cultures. Adipogenic differentiation, induced by 8-bromo-cAMP, was accompanied by stronger PKA activity and higher expression of cAMP-responsive genes, suggesting that stronger activation correlates with adipogenic differentiation. In addition, a whole-genome expression analysis showed an increase in expression of adipogenic genes in 8-br-cAMP-treated cells. Furthermore, by means of quantitative polymerase chain reaction, we show differences in peroxisome proliferator-activated receptor-γ activation, either alone or in combination with dexamethasone, thus demonstrating differential effects of the PKA pathway, most likely depending on its mode of activation.
Department of Tissue Regeneration, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.
Joyce
J
Doorn
Maarten
M
Leusink
Nathalie
N
Groen
Jeroen
J
van de Peppel
Johannes P T M
JP
van Leeuwen
Clemens A
CA
van Blitterswijk
Jan
J
de Boer
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D050156:Adipogenesis / Q000187:drug effects*; D000469:Alkaline Phosphatase / Q000378:metabolism; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D010012:Osteogenesis / Q000187:drug effects*; D047495:PPAR gamma / Q000378:metabolism
D047495:PPAR gamma; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003994:Bucladesine; D003907:Dexamethasone; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000469:Alkaline Phosphatase