title: Activation of protein kinase A and exchange protein directly activated by cAMP promotes adipocyte differentiation of human mesenchymal stem cells.
abstract: Human mesenchymal stem cells are primary multipotent cells capable of differentiating into several cell types including adipocytes when cultured under defined in vitro conditions. In the present study we investigated the role of cAMP signaling and its downstream effectors, protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac) in adipocyte conversion of human mesenchymal stem cells derived from adipose tissue (hMADS). We show that cAMP signaling involving the simultaneous activation of both PKA- and Epac-dependent signaling is critical for this process even in the presence of the strong adipogenic inducers insulin, dexamethasone, and rosiglitazone, thereby clearly distinguishing the hMADS cells from murine preadipocytes cell lines, where rosiglitazone together with dexamethasone and insulin strongly promotes adipocyte differentiation. We further show that prostaglandin I(2) (PGI(2)) may fully substitute for the cAMP-elevating agent isobutylmethylxanthine (IBMX). Moreover, selective activation of Epac-dependent signaling promoted adipocyte differentiation when the Rho-associated kinase (ROCK) was inhibited. Unlike the case for murine preadipocytes cell lines, long-chain fatty acids, like arachidonic acid, did not promote adipocyte differentiation of hMADS cells in the absence of a PPARγ agonist. However, prolonged treatment with the synthetic PPARδ agonist L165041 promoted adipocyte differentiation of hMADS cells in the presence of IBMX. Taken together our results emphasize the need for cAMP signaling in concert with treatment with a PPARγ or PPARδ agonist to secure efficient adipocyte differentiation of human hMADS mesenchymal stem cells.
authors.affiliation: Institute of Cell Biology and Genetics, College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Jia
authors.forename: Lise
authors.initials: L
authors.lastname: Madsen
authors.forename: Rasmus Koefoed
authors.initials: RK
authors.lastname: Petersen
authors.forename: Nathalie
authors.initials: N
authors.lastname: Techer
authors.forename: Reidun
authors.initials: R
authors.lastname: Kopperud
authors.forename: Tao
authors.initials: T
authors.lastname: Ma
authors.forename: Stein Ove
authors.initials: SO
authors.lastname: Døskeland
authors.forename: Gérard
authors.initials: G
authors.lastname: Ailhaud
authors.forename: Jinfu
authors.initials: J
authors.lastname: Wang
authors.forename: Ez-Zoubir
authors.initials: EZ
authors.lastname: Amri
authors.forename: Karsten
authors.initials: K
authors.lastname: Kristiansen
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D017667:Adipocytes / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology; D011464:Epoprostenol / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D009765:Obesity / Q000378:metabolism; D000077154:Rosiglitazone; D015398:Signal Transduction; D045162:Thiazolidinediones / Q000494:pharmacology
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D007328:Insulin; C116122:RAPGEF3 protein, human; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D003907:Dexamethasone; D011464:Epoprostenol; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D015056:1-Methyl-3-isobutylxanthine