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Shou X, Wang Y, Jiang Q, Chen J, Liu Q. miR-126 promotes M1 to M2 macrophage phenotype switching via VEGFA and KLF4. PeerJ 2023; 11:e15180. [PMID: 37020848 PMCID: PMC10069419 DOI: 10.7717/peerj.15180] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 03/14/2023] [Indexed: 04/03/2023] Open
Abstract
Background
Macrophage polarization and microRNA play crucial roles in the development of atherosclerosis (AS). The M1 macrophage phenotype contributes to the formation of plaques, while the M2 macrophage phenotype resolves inflammation and promotes tissue repair. MiR-126 has been found to play a role in regulating macrophage polarization in the context of AS. However, the exact mechanism of miR-126 requires further research.
Methods
The foam cell model was established by stimulating THP-1 with oxidized low-density lipoprotein (ox-LDL). We transfected foam cells with miR-126 mimic and its negative control. The transfection of miR-126 was implemented by riboFECT CP transfection kit. The levels of miR-126 and M1/M2 associated genes in foam cells were quantified using reverse transcription-quantitative PCR (RT-qPCR). Additionally, the expressions of CD86+ and CD206+ cells in foam cells were determined by flow cytometry. Western blotting and RT-qPCR were used to determine the protein and mRNA levels of the vascular endothelial growth factor A (VEGFA) and the transcriptional regulator Krüppel-like factor 4 (KLF4), respectively. Additionally, we detected endothelial cell migration after co-culturing endothelial cells and macrophages. MG-132 was used to indirectly activate the expression of VEGFA, and the expression of KLF4 was also evaluated.
Results
The activation of apoptosis and production of foam cells were boosted by the addition of ox-LDL. We transfected foam cells with miR-126 mimic and its negative control and observed that miR-126 greatly suppressed foam cell development and inhibited phagocytosis. Moreover, it caused pro-inflammatory M1 macrophages to switch to the anti-inflammatory M2 phenotype. This was reflected by the increase in anti-inflammatory gene expression and the decrease in pro-inflammatory gene expression. Additionally, miR-126 dramatically decreased the expressions of VEGFA and KLF4. The protein-protein interaction network analysis showed a significantly high correlation between miR-126, VEGFA, and KLF4. MiR-126 may also promote EC migration by activating macrophage PPAR γ expression and effectively suppressing macrophage inflammation. MG-132 indirectly activated the expression of VEGFA, and the expression of KLF4 also significantly increased, which indicates a direct or indirect relationship between VEGFA and KLF4.
Conclusion
Our study shows that miR-126 can reverse ox-LDL-mediated phagocytosis and apoptosis in macrophages. Consequently, the potential role of miR-126 was manifested in regulating macrophage function and promoting vascular endothelial migration.
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Affiliation(s)
- Xinyang Shou
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Yimin Wang
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Qingyu Jiang
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
| | - Jun Chen
- Zhejiang Chinese Medical University, Hangzhou, China
| | - Qiang Liu
- The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China
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Grether U, Benz J, Hartung T, Roth D. Scintillation Proximity Assay (SPA)-Based Radioligand Binding for PPARα, PPARγ, and PPARδ Receptors. Methods Mol Biol 2023; 2576:145-153. [PMID: 36152183 DOI: 10.1007/978-1-0716-2728-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) have been exploited as drug targets for combating multiple diseases. Several activators with different selectivity for the PPAR α, γ, and δ subtypes have been introduced into the market or have reached advanced clinical trials. Binding assays are of utmost importance for the discovery and profiling of such PPAR ligands. Binding assays are often based on radioligands, in particular, tritiated molecules are applied. We developed synthetic procedures for tritiating various PPAR agonists and applied these radioligands for setting up a scintillation proximity assay (SPA) for PPAR α, γ, and δ. These SPAs allow to assess the binding affinities of PPAR α, γ, and δ ligands, along with their respective subtype selectivity profiles. Therefore, SPA is an important tool for hit discovery and lead optimization campaigns aimed at identifying next-generation PPAR ligands.
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Affiliation(s)
- Uwe Grether
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
| | - Jörg Benz
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Thomas Hartung
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Doris Roth
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
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3
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Mallat SG. Dual renin-angiotensin system inhibition for prevention of renal and cardiovascular events: do the latest trials challenge existing evidence? Cardiovasc Diabetol 2013; 12:108. [PMID: 23866091 PMCID: PMC3726294 DOI: 10.1186/1475-2840-12-108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 07/15/2013] [Indexed: 02/06/2023] Open
Abstract
Circulatory and tissue renin-angiotensin systems (RAS) play a central role in cardiovascular (CV) and renal pathophysiology, making RAS inhibition a logical therapeutic approach in the prevention of CV and renal disease in patients with hypertension. The cardio- and renoprotective effects observed with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) monotherapy, together with the availability of a direct renin inhibitor (DRI), led to the investigation of the potential benefits of dual RAS inhibition. In small studies, ARB and ACE inhibitor combinations were shown to be beneficial in patients with CV or renal disease, with improvement in surrogate markers. However, in larger outcome trials, involving combinations of ACE inhibitors, ARBs or DRIs, dual RAS inhibition did not show reduction in mortality in patients with diabetes, heart failure, coronary heart disease or after myocardial infarction, and was in fact, associated with increased harm. A recent meta-analysis of all major trials conducted over the past 22 years involving dual RAS inhibition has clearly shown that the risk-benefit ratio argues against the use of dual RAS inhibition. Hence, the recent evidence clearly advocates against the use of dual RAS inhibition, and single RAS inhibition appears to be the most suitable approach to controlling blood pressure and improving patient outcomes.
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Cullin-3 regulates vascular smooth muscle function and arterial blood pressure via PPARγ and RhoA/Rho-kinase. Cell Metab 2012; 16:462-72. [PMID: 23040068 PMCID: PMC3474846 DOI: 10.1016/j.cmet.2012.08.011] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/31/2012] [Accepted: 08/31/2012] [Indexed: 12/26/2022]
Abstract
Dominant-negative (DN) mutations in the nuclear hormone receptor peroxisome proliferator-activated receptor-γ (PPARγ) cause hypertension by an unknown mechanism. Hypertension and vascular dysfunction are recapitulated by expression of DN PPARγ specifically in vascular smooth muscle of transgenic mice. DN PPARγ increases RhoA and Rho-kinase activity, and inhibition of Rho-kinase restores normal reactivity and reduces arterial pressure. RhoBTB1, a component of the Cullin-3 RING E3 ubiquitin ligase complex, is a PPARγ target gene. Decreased RhoBTB1, Cullin-3, and neddylated Cullin-3 correlated with increased levels of the Cullin-3 substrate RhoA. Knockdown of Cullin-3 or inhibition of cullin-RING ligase activity in aortic smooth muscle cells increased RhoA. Cullin-RING ligase inhibition enhanced agonist-mediated contraction in aortic rings from normal mice by a Rho-kinase-dependent mechanism, and it increased arterial pressure in vivo. We conclude that Cullin-3 regulates vascular function and arterial pressure, thus providing a mechanistic link between mutations in Cullin-3 and hypertension in humans.
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5
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Dietz M, Mohr P, Kuhn B, Maerki HP, Hartman P, Ruf A, Benz J, Grether U, Wright MB. Comparative molecular profiling of the PPARα/γ activator aleglitazar: PPAR selectivity, activity and interaction with cofactors. ChemMedChem 2012; 7:1101-11. [PMID: 22489042 PMCID: PMC3504387 DOI: 10.1002/cmdc.201100598] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 03/02/2012] [Indexed: 12/13/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear hormone receptors that control the expression of genes involved in a variety of physiologic processes, through heterodimerization with retinoid X receptor and complex formation with various cofactors. Drugs or treatment regimens that combine the beneficial effects of PPARα and γ agonism present an attractive therapeutic strategy to reduce cardiovascular risk factors. Aleglitazar is a dual PPARα/γ agonist currently in phase III clinical development for the treatment of patients with type 2 diabetes mellitus who recently experienced an acute coronary event. The potency and efficacy of aleglitazar was evaluated in a head-to-head comparison with other PPARα, γ and δ ligands. A comprehensive, 12-concentration dose-response analysis using a cell-based assay showed aleglitazar to be highly potent, with EC(50) values of 5 nM and 9 nM for PPARα and PPARγ, respectively. Cofactor recruitment profiles confirmed that aleglitazar is a potent and balanced activator of PPARα and γ. The efficacy and potency of aleglitazar are discussed in relation to other dual PPARα/γ agonists, in context with the published X-ray crystal structures of both PPARα and γ.
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Affiliation(s)
- Michel Dietz
- Discovery TechnologiesF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Peter Mohr
- Discovery ChemistryF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Bernd Kuhn
- Discovery ChemistryF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Hans Peter Maerki
- Discovery ChemistryF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Peter Hartman
- DTA CVM, F. Hoffmann-La Roche AGGrenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Armin Ruf
- Discovery TechnologiesF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Jörg Benz
- Discovery TechnologiesF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Uwe Grether
- Discovery ChemistryF. Hoffmann-La Roche AG, Grenzacherstrasse 124, Basel 4070 (Switzerland)
| | - Matthew B Wright
- Pharma Research & Early Development (pRED), F. Hoffmann-La Roche AGGrenzacherstrasse 124, Basel 4070 (Switzerland)
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Nisbet RE, Sutliff RL, Hart CM. The role of peroxisome proliferator-activated receptors in pulmonary vascular disease. PPAR Res 2011; 2007:18797. [PMID: 17710111 PMCID: PMC1940049 DOI: 10.1155/2007/18797] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2007] [Accepted: 04/30/2007] [Indexed: 02/07/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone
receptor superfamily that regulate diverse physiological processes ranging from lipogenesis to inflammation. Recent evidence has
established potential roles of PPARs in both systemic and pulmonary vascular disease and function. Existing treatment strategies
for pulmonary hypertension, the most common manifestation of pulmonary vascular disease, are limited by an incomplete
understanding of the underlying disease pathogenesis and lack of efficacy indicating an urgent need for new approaches to treat
this disorder. Derangements in pulmonary endothelial-derived mediators and endothelial dysfunction have been shown to play a
pivotal role in pulmonary hypertension pathogenesis. Therefore, the following review will focus on selected mediators implicated
in pulmonary vascular dysfunction and evidence that PPARs, in particular PPARγ, participate in their regulation and may provide
a potential novel therapeutic target for the treatment of pulmonary hypertension.
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Affiliation(s)
- Rachel E. Nisbet
- Department of Medicine, Emory University, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
- *Rachel E. Nisbet:
| | - Roy L. Sutliff
- Department of Medicine, Emory University, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
| | - C. Michael Hart
- Department of Medicine, Emory University, Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
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Desch M, Schreiber A, Schweda F, Madsen K, Friis UG, Weatherford ET, Sigmund CD, Sequeira Lopez ML, Gomez RA, Todorov VT. Increased renin production in mice with deletion of peroxisome proliferator-activated receptor-gamma in juxtaglomerular cells. Hypertension 2010; 55:660-6. [PMID: 20065157 DOI: 10.1161/hypertensionaha.109.138800] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We recently found that endogenous (free fatty acids) and pharmacological (thiazolidinediones) agonists of nuclear receptor Peroxisome proliferator-activated receptor (PPAR)gamma stimulate renin transcription. In addition, the renin gene was identified as a direct target of PPARgamma. The mouse renin gene is regulated by PPARgamma through a distal enhancer direct repeat closely related to consensus PPAR response element (PPRE). In vitro studies demonstrated that PPARgamma knockdown stimulated PPRE-driven transcription. These data predicted that deficiency of PPARgamma would upregulate mouse renin expression. Consistent with these observations knockdown of PPARgamma increased the transcription of a reporter gene driven by the mouse renin PPRE-like motif in vitro. To study the impact of PPARgamma on renin production in vivo, we used a cre/lox system to generate double-transgenic mice with disrupted PPARgamma locus in renin-producing juxtaglomerular (JG) cells of the kidney (RC-PPARgamma(fl/fl) mice). We provide evidence that PPARgamma expression was effectively reduced in JG cells of RC-PPARgamma(fl/fl) mice. Fluorescent immunohistochemistry showed stronger renin signal in RC-PPARgamma(fl/fl) than in littermate control RC-PPARgamma(wt/wt) mice. Renin mRNA levels and plasma renin concentration in RC-PPARgamma(fl/fl) mice were almost 2-fold higher than in littermate controls. Arterial blood pressure and pressure control of renal vascular resistance, which play decisive roles in the regulation of renin production were indistinguishable between RC-PPARgamma(wt/wt) and RC-PPARgamma(fl/fl) mice. These data demonstrate that the JG-specific PPARgamma deficiency results in increased mouse renin expression in vivo thus corroborating earlier in vitro results. PPARgamma appears to be a relevant transcription factor for the control of renin gene in JG cells.
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Affiliation(s)
- Michael Desch
- Institute of Physiology, University of Regensburg, D-93040 Regensburg, Germany
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8
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Zapata-Gonzalez F, Rueda F, Petriz J, Domingo P, Villarroya F, Diaz-Delfin J, de Madariaga MA, Domingo JC. Human dendritic cell activities are modulated by the omega-3 fatty acid, docosahexaenoic acid, mainly through PPARγ:RXR heterodimers: comparison with other polyunsaturated fatty acids. J Leukoc Biol 2008; 84:1172-82. [DOI: 10.1189/jlb.1007688] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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9
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Oz O, Tuncel E, Eryilmaz S, Fazlioglu M, Gul CB, Ersoy C, Ocak N, Dirican M, Cangur S, Baran I, Imamoglu S. Arterial elasticity and plasma levels of adiponectin and leptin in type 2 diabetic patients treated with thiazolidinediones. Endocrine 2008; 33:101-5. [PMID: 18392690 DOI: 10.1007/s12020-008-9058-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 03/26/2008] [Indexed: 01/13/2023]
Abstract
BACKGROUND Thiazolidinediones (TZDs) improve peripheral insulin sensitivity, but the effect on arterial stiffness is less clear. The aim of the present study was to assess the differential effect of pioglitazone or rosiglitazone on arterial stiffness and plasma levels of adiponectin and leptin in patients with type 2 diabetes mellitus. METHODS Thirty-five type 2 diabetic subjects were randomly assigned to receive pioglitazone (30 mg/day; n = 14), rosiglitazone (4 mg/day; n = 11), or placebo (medical nutrition therapy; n = 10) for 12 weeks. Changes in plasma glucose, glycosylated hemoglobin, insulin resistance (HOMA-IR), total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, adiponectin, and leptin were evaluated at baseline and after 12 weeks. In parallel, large arterial compliance (C1) and small arterial compliance (C2) were measured at baseline and at the end of treatment period. RESULTS At 12 weeks, the rosiglitazone (P = 0.026) and pioglitazone (P = 0.004) groups had a significant increase from baseline in adiponectin that was not seen in the medical nutrition therapy group. No significant changes in plasma leptin and in C1 and C2 elasticity indexes were observed over the entire study period in any of the treatment groups. CONCLUSIONS In this study of patients with type 2 diabetes, treatment with TZDs was associated with a significant improvement in adiponectin levels, although no significant effects were seen on leptin levels and arterial elasticity.
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Affiliation(s)
- Ozen Oz
- Department of Internal Medicine, Uludag University Medical School, Gorukle, Bursa, 16059, Turkey.
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Mangan S, Clancy P, Golledge J. Modulation of endothelial cell thrombomodulin by PPAR ligands--variation according to environment. Thromb Res 2007; 121:827-34. [PMID: 17869327 PMCID: PMC2577783 DOI: 10.1016/j.thromres.2007.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2007] [Revised: 07/19/2007] [Accepted: 08/09/2007] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Thrombomodulin (TM) is an important anti-coagulant protein that is down-regulated on endothelial cells overlying atherosclerotic plaques. We investigated the effects of the peroxisome proliferator-activated receptor (PPAR) ligands, fenofibrate and rosiglitazone, on the expression of TM ex vivo by advanced carotid atheromas, and in vitro by endothelial cells. METHODS Adjacent carotid atheroma biopsies were incubated in vehicle control or PPAR ligand in explant culture for 4 days. Human aortic endothelial cells were incubated with PPAR ligands in vitro. TM expression was measured by Western blotting and flow cytometry. TM activity was assessed by generation of activated protein C. RESULTS The PPAR-alpha activator, fenofibrate, up-regulated total TM expression within carotid explants by 1.7-fold (P<0.001) with no effect on activity. Rosiglitazone treatment had no effect on protein levels but reduced activity by 73% of the control (P<0.05). We noted disparate effects of PPAR ligands in atheroma samples from different patients and postulated that the response of endothelial cells to medication was influenced by the atheromatous environment. Incubation of human aortic endothelial cells with fenofibrate alone led to a dose-dependent increase in TM expression (P<0.05), however, in the presence of oxidized LDL a dose-dependent reduction in TM expression was induced by fenofibrate (P<0.05). CONCLUSIONS The ability of fenofibrate to increase endothelial cell and carotid atheroma TM protein expression suggests a potential therapeutic role for this medication. The response to PPAR ligands likely varies depending on the exact constituents of individual atherosclerotic plaques, such as the relative amount of oxidized LDL.
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Affiliation(s)
- Simone Mangan
- Vascular Biology Unit, School of Medicine, James Cook University, Townsville, Queensland, 4811, Australia
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De Ciuceis C, Amiri F, Iglarz M, Cohn JS, Touyz RM, Schiffrin EL. Synergistic vascular protective effects of combined low doses of PPARalpha and PPARgamma activators in angiotensin II-induced hypertension in rats. Br J Pharmacol 2007; 151:45-53. [PMID: 17351653 PMCID: PMC2012983 DOI: 10.1038/sj.bjp.0707215] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Protective cardiovascular effects of peroxisome proliferator activated receptor (PPAR)alpha and PPARgamma activators have been demonstrated. If used as vasoprotective agents in high risk vascular patients rather than for their metabolic benefits, these agents could be associated with unwanted side effects. As a proof of concept to support the use of combined low doses of PPARalpha and PPARgamma as vascular protective agents in high risk vascular patients, we tested the hypothesis that combined low doses of PPARalpha (fenofibrate) and PPARgamma (rosiglitazone) activators would provide vascular protective benefits similar to full individual doses of these PPAR agonists. EXPERIMENTAL APPROACH Male Sprague-Dawley rats infused with Ang II (120 ng kg(-1) min(-1)) were treated with rosiglitazone (1 or 2 mg kg(-1) day(-1)) alone or concomitantly with fenofibrate (30 mg kg(-1) day(-1)) for 7 days. Thereafter, vessels was assessed on a pressurized myograph, while NAD(P)H oxidase activity was determined by lucigenin chemiluminescence. Inflammation was evaluated using ELISA for NFkappaB and Western blotting for adhesion molecules. KEY RESULTS Ang II-induced blood pressure increase, impaired acetylcholine-induced vasorelaxation, altered vascular structure, and enhanced vascular NAD(P)H oxidase activity and inflammation were significantly reduced by low dose rosiglitazone+fenofibrate. CONCLUSIONS AND IMPLICATIONS Combined low doses of PPARalpha and PPARgamma activators attenuated development of hypertension, corrected vascular structural abnormalities, improved endothelial function, oxidative stress, and vascular inflammation. These agents used in low-dose combination have synergistic vascular protective effects. The clinical effects of combined low-dose PPARalpha and PPARgamma activators as vascular protective therapy, potentially with reduced side-effects and drug interactions, should be assessed.
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Affiliation(s)
- C De Ciuceis
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research, Sir Mortimer B Davis-Jewish General Hospital Montreal, Quebec, Canada
| | - F Amiri
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research, Sir Mortimer B Davis-Jewish General Hospital Montreal, Quebec, Canada
| | - M Iglarz
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research, Sir Mortimer B Davis-Jewish General Hospital Montreal, Quebec, Canada
| | - J S Cohn
- Hyperlipidemia and Atherosclerosis Research Group, Clinical Research Institute of Montreal, University of Montreal Montreal, Quebec, Canada
| | - R M Touyz
- Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa Ottawa, Ontario, Canada
| | - E L Schiffrin
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research, Sir Mortimer B Davis-Jewish General Hospital Montreal, Quebec, Canada
- Author for correspondence:
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Oak JH, Cai H. Attenuation of angiotensin II signaling recouples eNOS and inhibits nonendothelial NOX activity in diabetic mice. Diabetes 2007; 56:118-26. [PMID: 17192473 DOI: 10.2337/db06-0288] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Angiotensin II (Ang II) levels are increased in patients with diabetes, but mechanisms underlying its contribution to diabetic vascular diseases are incompletely understood. We recently reported that in aortic endothelial cells, Ang II induces endothelial nitric oxide synthase (eNOS) uncoupling to produce superoxide (O(2)*(-)) rather than nitric oxide (NO*), upon loss of the tetrahydrobiopterin (H(4)B) salvage enzyme dihydrofolate reductase (DHFR). Here, we found that streptozotocin-induced diabetic mice had a marked increase in aortic O(2)*(-) production, which was inhibited by N-nitro-l-arginine methyl ester hydrochloride, indicating uncoupling of eNOS. Ang II receptor type 1 blocker candesartan or ACE inhibitor captopril markedly attenuated eNOS-derived O(2)*(-) and hydrogen peroxide production while augmenting NO* bioavailability in diabetic aortas, implicating recoupling of eNOS. O(2)*(-) and NO* production were characteristically and quantitatively measured by electron spin resonance. DHFR expression was decreased in diabetic aortas but significantly restored by candesartan or captopril. Either also improved vascular H(4)B content and endothelium-dependent vasorelaxation in diabetes. Rac1-dependent NAD(P)H oxidase (NOX) activity was more than doubled in the endothelium-denuded diabetic aortas but was attenuated by candesartan or captopril, indicating that NOX remains active in nonendothelial vascular tissues, although uncoupled eNOS is responsible for endothelial production of O(2)*(-). These data demonstrate a novel role of Ang II in diabetic uncoupling of eNOS and that Ang II-targeted therapy improves endothelial function via the novel mechanism of recoupling eNOS. Dual effectiveness on uncoupled eNOS and NOX may explain the high efficacy of Ang II antagonists in restoring endothelial function.
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Affiliation(s)
- Jeong-Ho Oak
- Division of Molecular Medicine, Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, 650 Charles E. Young Dr. South, Suite BH550 CHS, Los Angeles, CA 90095, USA
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