MCP-1/CCR2 system is involved in high glucose-induced fibronectin and type IV collagen expression in cultured mesangial cells.
Monocyte chemoattractant protein-1 (MCP-1) is a potent chemokine that plays an important role in the recruitment of macrophages. Although previous studies have demonstrated the importance of MCP-1 in the pathogenesis of diabetic nephropathy (DN) in terms of inflammation, the role of MCP-1 and its receptor (C-C chemokine receptor 2; CCR2) in extracellular matrix (ECM) accumulation under diabetic conditions has been largely unexplored. This study was undertaken to investigate the functional role of the MCP-1/CCR2 system in high glucose-induced ECM (fibronectin and type IV collagen) protein expression in cultured mesangial cells (MCs). Mouse MCs were exposed to medium containing 5.6 mM glucose (NG), NG+24.4 mM mannitol (NG+M), or 30 mM glucose (HG) with or without mutant MCP-1 (mMCP-1), CCR2 small interfering (si)RNA, or CCR2 inhibitor (RS102895). To examine the relationship between MCP-1 and transforming growth factor (TGF)-beta1, MCs were also treated with TGF-beta1 (2 ng/ml) with or without mMCP-1 or CCR2 siRNA. Transient transfection was performed with Lipofectamine 2000 for 24 h. Cell viability was determined by an MTT assay, mouse and human MCP-1 and TGF-beta1 levels by ELISA, and CCR2 and ECM protein expression by Western blotting. Transfections of mMCP-1 and CCR2 siRNA increased human MCP-1 levels and inhibited CCR2 expression, respectively. HG-induced ECM protein expression and TGF-beta1 levels were significantly attenuated by mMCP-1, CCR2 siRNA, and RS102895 (P < 0.05). MCP-1 directly increased ECM protein expression, and this increase was inhibited by an anti-TGF-beta1 antibody. In addition, TGF-beta1-induced ECM protein expression was significantly abrogated by the inhibition of the MCP-1/CCR2 system (P < 0.05). These results suggest that an interaction between the MCP-1/CCR2 system and TGF-beta1 may contribute to ECM accumulation in DN.
Park
Jehyun
J
Yonsei University College of Medicine, Department of Internal Medicine, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul, Korea.
Ryu
Dong-Ryeol
DR
Li
Jin Ji
JJ
Jung
Dong-Sub
DS
Kwak
Seung-Jae
SJ
Lee
Sun Ha
SH
Yoo
Tae-Hyun
TH
Han
Seung Hyeok
SH
Lee
Jung Eun
JE
Kim
Dong Ki
DK
Moon
Sung Jin
SJ
Kim
Kunhong
K
Han
Dae Suk
DS
Kang
Shin-Wook
SW
D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D024141:Collagen Type IV / Q000378:metabolism*; D003928:Diabetic Nephropathies / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D050527:Mesangial Cells / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D034741:RNA, Small Interfering / Q000235:genetics; D054390:Receptors, CCR2 / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
C491768:Ccl2 protein, mouse; C515335:Ccr2 protein, mouse; D018932:Chemokine CCL2; D024141:Collagen Type IV; D005353:Fibronectins; D034741:RNA, Small Interfering; D054390:Receptors, CCR2; D053773:Transforming Growth Factor beta1; D005947:Glucose