Endothelin(B) receptor blocker inhibits high glucose-induced synthesis of fibronectin in human peritoneal mesothelial cells.
BACKGROUND
Long-term peritoneal dialysis using glucose-based dialysates is associated with peritoneal fibrosis. The object of this study was to investigate the hypothesis that endothelin (ET)-1, which is known to play an important role in various fibrotic diseases, may also be involved in peritoneal fibrosis using human peritoneal mesothelial cells (HPMC).


METHODS
HPMC were cultured with 4% D- or L-glucose, or loaded with 10 nmol/L ET-1. In some experiments, the ETA receptor antagonist BQ-123, the ETB receptor antagonist BQ-788, and antioxidants 4-hydroxy-2,2,6,6-tetramethyl-piperidine 1-oxyl (TEMPOL) and diphenyleneiodium chloride (DPI) were used. mRNA expression of ET-1, ETA receptor, ETB receptor, and fibronectin (FN) was analyzed by real-time polymerase chain reaction (real-time PCR). The protein levels for FN and ET-1 were measured by ELISA. CM-H2DCFDA-sensitive reactive oxygen species (ROS) were evaluated by flow cytometry.


RESULTS
D-Glucose significantly induced mRNA expression of ET-1 and the ETB receptor but not the ETA receptor. FN production under high glucose conditions was inhibited by BQ-788. ET-1 directly stimulated H PMC to increase mRNA expression of FN and CM-H2DCFDA-sensitive ROS production. BQ-788, TEMPOL, and DPI inhibited mRNA expression of FN induced by ET-1.


CONCLUSIONS
The present study suggests that high-glucose-induced FN synthesis is mediated by the ET-1/ETB receptor pathway and, therefore, an ETB receptor antagonist may be usefulin preventing FN production in HPMC.
Shimizu
Miyuki
M
Division of Total Renal Care Medicine, Department of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan.
Ishibashi
Yoshitaka
Y
Taki
Fumika
F
Shimizu
Hideki
H
Hirahara
Ichiro
I
Kaname
Shinya
S
Fujita
Toshiro
T
D016282:Aspartic Acid Endopeptidases / Q000235:genetics; D002478:Cells, Cultured; D017931:DNA Primers; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1 / Q000235:genetics; D000072396:Endothelin-Converting Enzymes; D004848:Epithelium / Q000187:drug effects / Q000502:physiology*; D005353:Fibronectins / Q000037:antagonists & inhibitors / Q000235:genetics*; D005947:Glucose / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000235:genetics; D010456:Peptides, Cyclic / Q000494:pharmacology*; D010529:Peritoneal Cavity / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1; D005353:Fibronectins; D010456:Peptides, Cyclic; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes; D005947:Glucose; C072247:cyclo(Trp-Asp-Pro-Val-Leu)