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Author |
Crosby, M.B.; Zhang, J.; Nowling, T.M.; Svenson, J.L.; Nicol, C.J.; Gonzalez, F.J.; Gilkeson, G.S. |
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Title |
Inflammatory modulation of PPAR gamma expression and activity |
Type |
Journal Article |
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Year |
2006 |
Publication |
Clinical immunology |
Abbreviated Journal |
Clin Immunol |
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Volume |
118 |
Issue |
2-3 |
Pages |
276-283 |
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Keywords |
Age Factors; Animals; Cell Line, Transformed; Cells, Cultured; Female; Inflammation Mediators/*physiology; Kidney/metabolism; Mesangial Cells/metabolism; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred MRL lpr; Mice, Knockout; Nitric Oxide/biosynthesis; Nitric Oxide Synthase Type II/biosynthesis/genetics; PPAR gamma/*biosynthesis/*genetics/metabolism; Up-Regulation/immunology |
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Abstract |
Nitric oxide (NO) production increases with age in the lupus-prone MRL/lpr mouse, paralleling disease activity. One mechanism for excess NO production in MRL/lpr mice may be a defect in down-regulatory mechanisms of the iNOS pathway. A potential modulator of NO is the nuclear hormone receptor peroxisome proliferation activated receptor gamma (PPARgamma). We demonstrate that renal PPARgamma protein expression was altered as disease progressed in MRL/lpr mice, which paralleled increased iNOS protein expression. Additionally, MRL/lpr-derived primary mesangial cells expressed less PPARgamma than BALB/c mesangial cells and produced more NO in response to LPS and IFNgamma. Furthermore, PPARgamma activity was reduced in mesangial cells following exposure to inflammatory mediators. This activity was restored with the addition of a NOS enzyme inhibitor. These results indicate that the activation of inflammatory pathways may lead to reduced activity and expression of PPARgamma, further exacerbating the disease state. |
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Address |
Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA |
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English |
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ISSN |
1521-6616 |
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Notes |
PMID:16303334 |
Approved |
no |
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Call Number |
refbase @ user @ |
Serial |
67 |
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Author |
Crosby, M.B.; Svenson, J.L.; Zhang, J.; Nicol, C.J.; Gonzalez, F.J.; Gilkeson, G.S. |
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Title |
Peroxisome proliferation-activated receptor (PPAR)gamma is not necessary for synthetic PPARgamma agonist inhibition of inducible nitric-oxide synthase and nitric oxide |
Type |
Journal Article |
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Year |
2005 |
Publication |
The Journal of pharmacology and experimental therapeutics |
Abbreviated Journal |
J Pharmacol Exp Ther |
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Volume |
312 |
Issue |
1 |
Pages |
69-76 |
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Keywords |
Animals; Cell Line; Gene Expression/drug effects; Macrophages/drug effects/metabolism; Mice; Mice, Inbred C57BL; Nitric Oxide/*metabolism; Nitric Oxide Synthase/*metabolism; Nitric Oxide Synthase Type II; PPAR delta/metabolism; PPAR gamma/*agonists/deficiency; Thiazolidinediones/pharmacology |
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Abstract |
Peroxisome proliferation-activated receptor (PPAR)gamma agonists inhibit inducible nitric-oxide synthase (iNOS), tumor necrosis factor-alpha, and interleukin-6. Because of these effects, synthetic PPARgamma agonists, including thiazolidinediones, are being studied for their impact on inflammatory disease. The anti-inflammatory concentrations of synthetic PPARgamma agonists range from 10 to 50 microM, whereas their binding affinity for PPARgamma is in the nanomolar range. The specificity of synthetic PPARgamma agonists for PPARgamma at the concentrations necessary for anti-inflammatory effects is thus in question. We report that PPARgamma is not necessary for the inhibition of iNOS by synthetic PPARgamma agonists. RAW 264.7 macrophages possess little PPARgamma, yet lipopolysaccharide (LPS)/interferon (IFN)gamma-induced iNOS was inhibited by synthetic PPARgamma agonists at 20 microM. Endogenous PPARgamma was inhibited by the transfection of a dominant-negative PPARgamma construct into murine mesangial cells. In the transfected cells, synthetic PPARgamma agonists inhibited iNOS production at 10 microM, similar to nontransfected cells. Using cells from PPARgamma Cre/lox conditional knockout mice, baseline and LPS/IFNgamma-induced nitric oxide levels were higher in macrophages lacking PPARgamma versus controls. However, synthetic PPARgamma agonists inhibited iNOS at 10 microM in the PPARgamma-deficient cells, similar to macrophages from wild-type mice. These results indicate that PPARgamma is not necessary for inhibition of iNOS expression by synthetic PPARgamma agonists at concentrations over 10 microM. Intrinsic PPARgamma function, in the absence of synthetic agonists, however, may play a role in inflammatory modulation. |
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Address |
Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA |
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English |
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0022-3565 |
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Notes |
PMID:15356214 |
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no |
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Call Number |
refbase @ user @ |
Serial |
73 |
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Permanent link to this record |