title: Effect of magnolol on TGF-beta1 and fibronectin expression in human retinal pigment epithelial cells under diabetic conditions.
abstract: Magnolol, a natural product isolated from Magnolia officinalis, has various pharmacological effects, such inhibition of effect on inflammation and tumor metastasis, protection against cerebral ischaemic injury, and potent antioxidant activity. In this present study, we evaluated the inhibitory effects of magnolol on transforming growth factor-beta1 (TGF-beta1) and fibronectin expression induced by high concentrations of glucose or S100b (a specific receptor of advance glycation end products ligand) in human retinal pigment epithelial cells (human RPE cells). No effect on cell growth was found with magnolol (up to 20 microg/ml) using a colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltertrazolium bromide (MTT) assay. High glucose (25 mM) or S100b (5 microg/ml) induced increases in expression of TGF-beta1 and fibronectin. The increases in TGF-beta1 and fibronectin expression with high glucose or S100b were prevented by magnolol in a dose-dependent manner. Also, magnolol inhibited extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)/Akt activation. The present study demonstrates that high glucose- or S100b-induced TGF-beta1 and fibronectin expression, but this increased expression is inhibited by magnolol via the ERK/MAPK/Akt signaling pathway in human RPE cells.
authors.affiliation: Department of Herbal Pharmaceutical Development, Korea Institute of Oriental Medicine, 461-24, Jeonmin-dong, Yuseng-gu, Daejeon, 305-811, Republic of Korea.
authors.forename: Young Sook
authors.initials: YS
authors.lastname: Kim
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Jung
authors.forename: Nan Hee
authors.initials: NH
authors.lastname: Kim
authors.forename: Yun Mi
authors.initials: YM
authors.lastname: Lee
authors.forename: Jin Sook
authors.initials: JS
authors.lastname: Kim
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism; D017705:Lignans / Q000737:chemistry / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D031566:Magnolia / Q000737:chemistry; D015394:Molecular Structure; D009414:Nerve Growth Factors / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism
chemical_list: D001713:Biphenyl Compounds; D005353:Fibronectins; D017705:Lignans; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human; D016212:Transforming Growth Factor beta; C005498:magnolol; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D005947:Glucose