title: Effect of phosphatidyl inositol 3-kinase, extracellular signal-regulated kinases 1/2, and p38 mitogen-activated protein kinase inhibition on osteogenic differentiation of muscle-derived stem cells.
abstract: Skeletal muscle-derived stem cells (MDSCs) can undergo osteogenesis when treated with bone morphogenetic proteins (BMPs), making them a potential cell source for bone tissue engineering. The signaling pathways that regulate BMP4-induced osteogenesis in MDSCs are not well understood, although they may provide a means to better regulate differentiation during bone regeneration. The objective of this study was to characterize the signaling pathways involved in the BMP4-induced osteogenesis of MDSCs. Cells were treated with BMP4 and specific inhibitors to the extracellular signal-regulated kinases 1/2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and phosphatidyl inositol 3-kinase (PI3K) pathways (PD98059, SB203580, and Ly294002, respectively). Cellular proliferation, expression of osteoblast-related genes, alkaline phosphatase (ALP) activity, and tissue mineralization were measured to determine the role of each pathway in the osteogenic differentiation of MDSCs. Inhibition of the ERK1/2 pathway increased ALP activity and mineralization, whereas inhibition of the p38 MAPK pathway decreased osteogenesis, suggesting opposing roles of these pathways in the BMP4-induced osteogenesis of MDSCs. Inhibition of the PI3K pathway significantly increased mineralization by MDSCs. These findings highlight the involvement of the ERK1/2, p38 MAPK, and PI3K pathways in opposing capacities in MDSC differentiation and warrant further investigation, as it may identify novel therapeutic targets for the development of stem cell-based therapies for bone tissue engineering.
authors.affiliation: Stem Cell Research Center, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA.
authors.forename: Karin A
authors.initials: KA
authors.lastname: Payne
authors.forename: Laura B
authors.initials: LB
authors.lastname: Meszaros
authors.forename: Julie A
authors.initials: JA
authors.lastname: Phillippi
authors.forename: Johnny
authors.initials: J
authors.lastname: Huard
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D032342:Muscle Cells / Q000166:cytology* / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D055415:Bone Morphogenetic Protein 4; D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines; D048051:p38 Mitogen-Activated Protein Kinases; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one