title: Emodin ameliorates glucose-induced morphologic abnormalities and synthesis of transforming growth factor beta1 and fibronectin by human peritoneal mesothelial cells.
abstract: OBJECTIVE
  Excessive synthesis and deposition of matrix proteins by peritoneal mesothelial cells can lead to structural and functional changes in the peritoneal membrane, jeopardizing the long-term efficacy of peritoneal dialysis (PD). Prolonged exposure to high glucose concentrations in PD fluid has been implicated as a major stimulus to matrix accumulation, through the induction of transforming growth factor beta1 (TGFbeta1). This study investigated the effect of emodin (3-methyl-1,6,8-trihydroxyanthraquinone) on TGFbeta1 and fibronectin (FN) synthesis in human peritoneal mesothelial cells (HPMCs) under high glucose concentration.
  
  
  METHODS
  The HPMCs were preconditioned in either 5 mmol/L or 30 mmol/L D-glucose for 2 weeks prior to the addition of emodin. Cell viability was assessed by MTT assay and lactate dehydrogenase (LDH) release. Morphology of HPMCs was studied by phase-contrast microscopy. Modulation of TGFbeta1 and FN synthesis at transcription and translation were investigated by reverse transcriptase polymerase chain reaction (RT-PCR), ELISA, and Western blot analysis.
  
  
  RESULTS
  When cultured under 30 mmol/L D-glucose, HPMCs demonstrated increased cell volume, multinucleation, and denudation of the monolayer, as compared with cells cultured under a physiologic (5 mmol/L) glucose concentration. High glucose concentration induced TGFbeta1 synthesis by HPMCs (217.17 +/- 14.88 pg/mL at 5 mmol/L D-glucose vs 370.33 +/- 20.67 pg/mL at 30 mmol/L D-glucose, p < 0.0001), and FN synthesis was induced at transcription and translation. Mannitol at 30 mmol/L did not affect HPMC morphology; matrix synthesis was also unaltered. Administration of emodin together with 30 mmol/L D-glucose resulted in amelioration of cell enlargement and exfoliation, and abrogation of TGFbeta1 induction (370.33 +/- 20.67 pg/mL for 30 mmol/L D-glucose alone vs 260.50 +/- 17.89 pg/mL for 30 mmol/L D-glucose + emodin, p < 0.0001). Synthesis of FN induced by high glucose was also reduced by 40% in the presence of emodin.
  
  
  CONCLUSIONS
  These findings provide the first evidence that emodin can ameliorate high glucose-induced matrix synthesis in HPMCs by suppression of TGFbeta1. Emodin may thus be useful in preserving peritoneal integrity in PD.
authors.affiliation: Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, PR China.
authors.forename: S
authors.initials: S
authors.lastname: Yung
authors.forename: Z H
authors.initials: ZH
authors.lastname: Liu
authors.forename: K N
authors.initials: KN
authors.lastname: Lai
authors.forename: L S
authors.initials: LS
authors.lastname: Li
authors.forename: T M
authors.initials: TM
authors.lastname: Chan
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004642:Emodin / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D005353:Fibronectins / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D008353:Mannitol / Q000494:pharmacology; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000378:metabolism* / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics; D053773:Transforming Growth Factor beta1
chemical_list: D005353:Fibronectins; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D008353:Mannitol; D005947:Glucose; D004642:Emodin