Prednisolone inhibits hyperosmolarity-induced expression of MCP-1 via NF-kappaB in peritoneal mesothelial cells.
The mechanism of peritoneal fibrosis in patients on continuous ambulatory peritoneal dialysis (CAPD) is poorly elucidated. We investigated the cellular mechanism of high-glucose-induced expression of monocyte chemoattractant protein-1 (MCP-1), which is important in recruiting monocytes into the peritoneum and progression of peritoneal fibrosis, and examined the inhibitory mechanism of glucocorticoids. Rat peritoneal mesothelial cells were cultured in high-glucose-containing medium and then analyzed for phosphorylation levels of p42/44 and p38 mitogen-activated protein (MAP) kinases (MAPK), MAPK or extracellular signal-regulated kinase kinase (MEK)1/2, c-Jun N-terminal kinase (JNK)1/2, and protein kinase C (PKC) by Western blotting. Expression of MCP-1 was examined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. DNA-binding activity of nuclear factor (NF)-kappaB was measured by electrophoretic mobility shift assay. High glucose increased MCP-1 mRNA and MCP-1 protein expression. Although glucose increased phosphorylation of MEK1/2, p42/44 MAPK, p38 MAPK, JNK1/2, and PKC, and DNA-binding activity of NF-kappaB, its effect on MCP-1 expression was suppressed only by PKC and NF-kappaB inhibitors. Mannitol caused a similar increase in PKC and NF-kappaB activation and MCP-1 synthesis. Prednisolone increased I-kappaB-alpha expression and inhibited glucose/mannitol-induced NF-kappaB DNA binding and MCP-1 expression without affecting PKC phosphorylation. The inhibitory effects of prednisolone on MCP-1 expression were reversed by mifepristone, a glucocorticoid receptor antagonist. Our results indicate that glucose induces MCP-1 mainly through hyperosmolarity by activating PKC and its downstream NF-kappaB, and that such effect was inhibited by prednisolone, suggesting the efficacy of prednisolone in preventing peritoneal fibrosis in patients on CAPD.
Matsuo
H
H
The Second Department of Internal Medicine, University of Occupational and Environmental Health School of Medicine, and Kidney Center, University Hospital, Kitakyushu, Japan.
Tamura
M
M
Kabashima
N
N
Serino
R
R
Tokunaga
M
M
Shibata
T
T
Matsumoto
M
M
Aijima
M
M
Oikawa
S
S
Anai
H
H
Nakashima
Y
Y
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D004848:Epithelium / Q000737:chemistry / Q000503:physiopathology; D005355:Fibrosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000494:pharmacology; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D015735:Mifepristone / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000502:physiology*; D009994:Osmolar Concentration; D010531:Peritoneal Dialysis, Continuous Ambulatory; D010537:Peritoneum / Q000166:cytology* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011239:Prednisolone / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats
C491766:Ccl2 protein, rat; D018932:Chemokine CCL2; D020672:I-kappa B Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D015735:Mifepristone; D011239:Prednisolone; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D005947:Glucose