Mycophenolic acid inhibits oleic acid-induced mesangial cell activation through both cellular reactive oxygen species and inosine monophosphate dehydrogenase 2 pathways.
The synthesis of extracellular matrix (ECM) in mesangial cells (MCs) plays important roles in the development and progression of renal diseases, including chronic allograft nephropathy. Mycophenolic acid (MPA), an inhibitor of inosine monophosphate dehydrogenase 2 (IMPDH2), suppresses MC proliferation and ECM synthesis. However, the exact inhibitory mechanism of MPA on MCs has not been clearly elucidated. In this study we compared the inhibitory effects of MPA and IMPDH2 reduction [by using small interfering RNA (siRNA)] on oleic acid (OA)-induced fibronectin secretion and cellular reactive oxygen species (ROS) in mouse MCs. Growth-arrested MCs were stimulated with OA in the presence or absence of MPA, IMPDH2 siRNA, N-acetylcysteine (NAC), transforming growth factor beta (TGF-beta) antibody or exogenous guanosine. Fibronectin secretion into the medium was examined by Western blot, dichlorodihydrofluorescein (DCF)-sensitive cellular ROS by fluorescence-activated cell scanning (FACS), TGF-beta levels in the media by enzyme-linked immunosorbent assay (ELISA). OA increased fibronectin secretion, TGF-beta and cellular ROS levels. A TGF-beta neutralizing antibody effectively suppressed OA-induced fibronectin secretion. NAC and MPA completely suppressed OA-induced fibronectin secretion and decreased the levels of TGF-beta and cellular ROS. However, IMPDH2 siRNA partly inhibited OA-induced MC activation. Exogenous guanosine successfully reversed the inhibitory effects of IMPDH2 siRNA on OA-induced MC activation. Pleiotropic inhibitory effect of MPA on OA-induced mouse MC activation was mediated via its antioxidant effect on cellular ROS production and partly via inhibition of IMPDH2 itself. Our results implicate ROS as an alternative therapeutic target for the prevention of hyperlipidemia-related glomerulopathy, chronic allograft nephropathy, and subsequent graft loss.
Huh
Kyu Ha
KH
The Research Institute for Transplantation, Seoul, Korea.
Ahn
Hyung Joon
HJ
Park
Jehyun
J
Ju
Man Ki
MK
Song
Jae Sook
JS
Kim
Myoung Soo
MS
Kim
Soon Il
SI
Kim
Yu Seun
YS
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000737:chemistry / Q000378:metabolism; D004336:Drug Antagonism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005353:Fibronectins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D006151:Guanosine / Q000494:pharmacology; D007168:IMP Dehydrogenase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D050527:Mesangial Cells / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009173:Mycophenolic Acid / Q000494:pharmacology*; D019301:Oleic Acid / Q000494:pharmacology*; D034622:RNA Interference / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000276:immunology
D019138:Antibodies, Blocking; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D005353:Fibronectins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D016212:Transforming Growth Factor beta; D006151:Guanosine; D019301:Oleic Acid; D007168:IMP Dehydrogenase; C488212:IMPDH2, mouse; D009173:Mycophenolic Acid; D000111:Acetylcysteine