Role of high glucose-induced nuclear factor-kappaB activation in monocyte chemoattractant protein-1 expression by mesangial cells.
Although high glucose (HG) has been shown to induce nuclear factor-kappaB (NF-kappaB) activation in vascular cells, the upstream regulation and the biologic significance of NF-kappaB activation in diabetic renal injury are not clear. It was, therefore, examined if HG-induced generation of reactive oxygen species (ROS) and protein kinase C (PKC) activation are involved in NF-kappaB activation in mesangial cells (MC), and the role of NF-kappaB activation in HG-induced monocyte chemoattractant protein-1 (MCP-1) expression by MC was further investigated. Recent observations suggest that MCP-1 may play a role in the development and progression of diabetic nephropathy. HG rapidly induced NF-kappaB activation in MC as estimated by electrophoretic mobility shift assay. Supershift assay suggests that most of the binding activity arose from p50/p50 and p50/p65 dimers. Antioxidants, pyrrolidine dithiocarbamate, N-acetyl-L-cystein, and trolox effectively inhibited HG-induced NF-kappaB activation in MC. HG rapidly generated dichlorofluorescin-sensitive intracellular ROS in MC as measured by laser-scanning confocal microscopy. HG also activated PKC rapidly in MC. Inhibition of PKC effectively blocked HG-induced intracellular ROS generation and NF-kappaB activation in MC. HG increased MCP-1 mRNA expression by 1.9-fold and protein secretion by 1.6-fold that of control glucose in MC transfected with control vector but not in MC transfected with dominant negative mutant inhibitor of NF-kappaB (IkappaBalphaM). Inhibition of either PKC or ROS effectively blocked HG-induced, but not basal, MCP-1 protein secretion by MC transfected with control vector. Thus this study demonstrates that HG rapidly activates NF-kappaB in MC through PKC and ROS and suggests that HG-induced NF-kappaB activation in MC may play a role in diabetic renal injury through upregulation of MCP-1 mRNA and protein expression.
Ha
Hunjoo
H
*Hyonam Kidney Laboratory, Soon Chun Hyang University, Seoul, Korea; and †University College London Medical School, The Rayne Institute, London, United Kingdom.
Yu
Mi Ra
MR
*Hyonam Kidney Laboratory, Soon Chun Hyang University, Seoul, Korea; and †University College London Medical School, The Rayne Institute, London, United Kingdom.
Choi
Yoon Jin
YJ
*Hyonam Kidney Laboratory, Soon Chun Hyang University, Seoul, Korea; and †University College London Medical School, The Rayne Institute, London, United Kingdom.
Kitamura
Masanori
M
*Hyonam Kidney Laboratory, Soon Chun Hyang University, Seoul, Korea; and †University College London Medical School, The Rayne Institute, London, United Kingdom.
Lee
Hi Bahl
HB
*Hyonam Kidney Laboratory, Soon Chun Hyang University, Seoul, Korea; and †University College London Medical School, The Rayne Institute, London, United Kingdom.
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000008:administration & dosage* / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
D000975:Antioxidants; D018932:Chemokine CCL2; D004791:Enzyme Inhibitors; D016328:NF-kappa B; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D011493:Protein Kinase C; D005947:Glucose