title: Effect of Glucagon-like Peptide-1 on the Differentiation of Adipose-derived Stem Cells into Osteoblasts and Adipocytes.
abstract: OBJECTIVE
  Glucagon-like peptide-1 (GLP-1) is an intestinally secreted hormone and it plays an important role in the regulation of glucose homeostasis. However, the possible role of GLP-1 in the differentiation of adipose-derived stem cells (ADSCs) remains unknown. Therefore this study investigated the effect of GLP-1 on the differentiation of ADSCs into osteoblasts and adipocytes.
  
  
  METHODS
  ADSCs were isolated from human adipose tissues of the abdomens, cultured and characterized by flow cytometry and multi-lineage potential assay. ADSCs were induced in osteogenic and adipogenic media treated with two different doses (10 and 100 nM) of GLP-1, and then the effect of GLP-1 on differentiation of ADSCs into osteoblast and adipocyte was examined. The signaling pathway involved in these processes was also examined.
  
  
  RESULTS
  Isolated human ADSCs expressed mesenchymal stem cell (MSC) specific markers as well as GLP-1 receptor (GLP-1R) proteins. They also showed multiple-lineage potential of MSC. GLP-1 was upregulated the activity and mRNA expression of osteoblast-specific marker, alkaline phosphatase and the mineralization of calcium. In contrast, GLP-1 significantly suppressed the expression of adipocyte-specific markers, peroxisome proliferator-activated receptor gamma (PPAR-γ), lipoprotein lipase (LPL) and adipocyte protein 2 (AP2). This decreased expression of adipocyte specific markers caused by GLP-1 was significantly reversed by the treatment of extracellular signal-regulated kinase (ERK) inhibitor, PD98059 (P < 0.05).
  
  
  CONCLUSIONS
  This result demonstrates that GLP-1 stimulates osteoblast differentiation in ADSCs, whereas it inhibits adipocyte differentiation. The ERK signaling pathway seems to be involved in these differentiation processes mediated by GLP-1.
authors.affiliation: Department of Molecular Biology, Natural Science College, Pusan National University, Busan, Korea.
authors.forename: Hye Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Research Center for Anti-Aging Technology Development, Pusan National University, Busan, Korea.
authors.forename: Bo Sun
authors.initials: BS
authors.lastname: Joo
authors.affiliation: Research Center for Anti-Aging Technology Development, Pusan National University, Busan, Korea.
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Department of Obstetrics and Gynecology, Kosin University Hospital, Busan, Korea.
authors.forename: Heung Yeol
authors.initials: HY
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Busan Adventist Hospital, Busan, Korea.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Ock
authors.affiliation: Department of Pediatric Cardiology, Dona-A University Hospital, Busan, Korea.
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Lee
keywords: Adipocytes; Adipogenesis; Adipose tissue; Cell differentiation; Glucagon-like peptide 1; Osteogenesis