title: The effect of PKC activation and inhibition on osteogenic differentiation of human mesenchymal stem cells.
abstract: Human mesenchymal stem cells (hMSCs) are being considered for several areas of clinical therapy, due to their multipotent nature. For instance, osteogenic hMSCs are applied in bone tissue engineering, but current differentiation protocols need further optimization before they can be clinically applied. Protein kinase C (PKC) family members have been implicated in bone metabolism, which prompted us to use a pharmaceutical approach to manipulate PKC signalling in hMSCs. Inhibition of PKC resulted in a dose-dependent inhibition of dexamethasone-induced osteogenic differentiation. Surprisingly, PKC activation using phorbol 12-myristate 13-acetate (PMA) also resulted in inhibition of osteogenesis, although we observed that inhibition was more pronounced at low than at high concentrations of PMA. Furthermore, we observed that inhibition of PKCdelta blocked alkaline phosphatase (ALP, an early marker of osteogenic differentiation) expression, whereas inhibition of the conventional PKC subfamily and PKCmicro using Gö6976 resulted in an induction of ALP activity, collagen (I) expression and mineralization. In conclusion, inhibition of the conventional PKCs/PKCmicro and activation of PKCdelta could further benefit osteogenic differentiation of hMSCs in vitro and in vivo, which is currently under investigation.
authors.affiliation: MIRA Institute for Biomedical Technology, Department of Tissue Regeneration, University of Twente, Enschede, The Netherlands.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Eugene
authors.initials: E
authors.lastname: Someren
authors.forename: Anouk
authors.initials: A
authors.lastname: Mentink
authors.forename: Ruud
authors.initials: R
authors.lastname: Licht
authors.forename: Koen
authors.initials: K
authors.lastname: Dechering
authors.forename: Clemens
authors.initials: C
authors.lastname: van Blitterswijk
authors.forename: Jan
authors.initials: J
authors.lastname: de Boer
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
chemical_list: D000098:Acetophenones; D001578:Benzopyrans; D002227:Carbazoles; D007527:Isoenzymes; D047428:Protein Kinase Inhibitors; C081021:Go 6976; C085746:rottlerin; D011493:Protein Kinase C