title: Exendin-4 promotes proliferation and differentiation of MC3T3-E1 osteoblasts by MAPKs activation.
abstract: Glucagon-like peptide-1 (GLP1) and its receptor agonist have been previously reported to play a positive role in bone metabolism in aged ovariectomized rats and insulin-resistant models. However, whether GLP1 has a direct effect on the proliferation and differentiation of osteoblasts or any cellular mechanism for this potential role is unknown. We examined the effects of the GLP1 receptor agonist exendin-4 on the proliferation, differentiation, and mineralization of mouse osteoblastic MC3T3-E1 cells. GLP1 receptor was detected in MC3T3-E1 cells by polymerase chain reaction (PCR) and Western blot assay. Cell proliferation was assessed using MTT assay, revealing that exendin-4 increased cell proliferation at effective concentrations between 10(-10) and 10(-5) M. Quantitative PCR analysis showed that exendin-4 increased the mRNA expression of the differentiation markers alkaline phosphatase (ALP), collagen-1 (COL1), osteocalcin (OC), and runt-related transcription factor 2 (RUNX2) under osteogenic conditions. Alizarin red staining confirmed that 10(-7) M exendin-4 increased osteoblast mineralization by 18.7%. Exendin-4 upregulated the phosphorylation of ERK1/2, p38, and JNK, with the peak effect at 1.5 h in the Western blot analysis. The use of selective MAPK inhibitors, namely PD98059, SB203580, and SP600125, blocked the effects of exendin-4 on kinase activation (ERK1/2, p38, and JNK), as well as cell proliferation and differentiation in MC3T3-E1 cells. These findings demonstrate that exendin-4 promotes both the proliferation and differentiation of preosteoblasts MC3T3-E1 via activation of the MAPK pathway.
authors.affiliation: Department of EndocrinologyFirst Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Yingyu
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of GeriatricsFirst Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Su
authors.affiliation: Department of EndocrinologySecond Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.
authors.forename: Xing
authors.initials: X
authors.lastname: Zhong
authors.affiliation: Department of EndocrinologyFirst Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Guohong
authors.affiliation: Department of EndocrinologyFirst Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Haipeng
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Department of EndocrinologyFirst Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of EndocrinologyFirst Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China xlingling58@163.com.
authors.forename: Lingling
authors.initials: L
authors.lastname: Xiu
mesh_terms: D000818:Animals; D015415:Biomarkers; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000077270:Exenatide; D015870:Gene Expression; D000067757:Glucagon-Like Peptide-1 Receptor / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D014688:Venoms / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D000067757:Glucagon-Like Peptide-1 Receptor; D010455:Peptides; D047428:Protein Kinase Inhibitors; D014688:Venoms; D000077270:Exenatide
keywords: GLP1; MAPK; MC3T3-E1 cells; exendin-4; osteoblast