scholarly journals Attenuation of Colon Inflammation through Activators of the Retinoid X Receptor (Rxr)/Peroxisome Proliferator–Activated Receptor γ (Pparγ) Heterodimer

2001 ◽  
Vol 193 (7) ◽  
pp. 827-838 ◽  
Author(s):  
Pierre Desreumaux ◽  
Laurent Dubuquoy ◽  
Sophie Nutten ◽  
Michel Peuchmaur ◽  
Walter Englaro ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Synergistic Effects ◽  
Survival Rates ◽  
Nuclear Factor Κb ◽  
Retinoid X Receptor ◽  
Trinitrobenzene Sulfonic Acid ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Colon Inflammation

The peroxisome proliferator–activated receptor γ (PPARγ) is highly expressed in the colon mucosa and its activation has been reported to protect against colitis. We studied the involvement of PPARγ and its heterodimeric partner, the retinoid X receptor (RXR) in intestinal inflammatory responses. PPARγ1/− and RXRα1/− mice both displayed a significantly enhanced susceptibility to 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis compared with their wild-type littermates. A role for the RXR/PPARγ heterodimer in the protection against colon inflammation was explored by the use of selective RXR and PPARγ agonists. TNBS-induced colitis was significantly reduced by the administration of both PPARγ and RXR agonists. This beneficial effect was reflected by increased survival rates, an improvement of macroscopic and histologic scores, a decrease in tumor necrosis factor α and interleukin 1β mRNA levels, a diminished myeloperoxidase concentration, and reduction of nuclear factor κB DNA binding activity, c-Jun NH2-terminal kinase, and p38 activities in the colon. When coadministered, a significant synergistic effect of PPARγ and RXR ligands was observed. In combination, these data demonstrate that activation of the RXR/PPARγ heterodimer protects against colon inflammation and suggest that combination therapy with both RXR and PPARγ ligands might hold promise in the clinic due to their synergistic effects.

scholarly journals MicroRNA-511-3p mediated modulation of the peroxisome proliferator-activated receptor gamma (PPARγ) controls LPS-induced inflammatory responses in human monocyte derived DCs

2020 ◽  
Author(s):  
Dennis Awuah ◽  
Alisa Ruisinger ◽  
Meshal Alobaid ◽  
Chidimma Mbadugha ◽  
Amir M. Ghaemmaghami
Keyword(s):  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Human Monocyte ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Peroxisome Proliferator Activated Receptor ◽  
Inflammatory Cytokine Production ◽  
And Function ◽  
First Time ◽  
Selection Of

AbstractThe peroxisome proliferator activated receptor gamma (PPARγ) is a ligand activated transcription factor expressed in dendritic cells (DCs), where it exerts anti-inflammatory responses against TLR4-induced inflammation. Recently, microRNA-511 (miR-511) has also emerged as a key player in controlling TLR4-mediated signalling, and in regulating the function of DCs. Interestingly, PPARγ has been previously highlighted as a putative target of miR-511 activity; however the link between miR-511 and PPARγ and its influence on human DC function within the context of LPS-induced inflammatory responses is unknown. Using a selection of miR-511-3p-specific inhibitors and mimics, we demonstrate for the first time that up or downregulation of miR-511-3p inversely correlates with PPARγ mRNA levels and transcriptional activity following treatment with PPARγ synthetic agonist rosiglitazone (RSG), in the presence or absence of LPS. Additionally, we show that PPARγ activation with RSG modulates LPS-induced DC activation and downregulates pro-inflammatory cytokine production following downregulation of miR-511-3p. Lastly, PPARγ activation was shown to suppress LPS-mediated induction of indoleamine 2,3-dioxygenase (IDO) activity in DCs, most likely due to changes in miR-511-3p expression. These data suggest that PPARγ-induced modulation of DC phenotype and function is influenced by miR-511-3p expression, which may serve as a potential therapeutic target against inflammatory diseases.

Regulation of dectin-1–mediated dendritic cell activation by peroxisome proliferator–activated receptor-gamma ligand troglitazone

Blood ◽  
2011 ◽  
Vol 117 (13) ◽  
pp. 3569-3574 ◽  
Author(s):  
Grethe Kock ◽  
Anita Bringmann ◽  
Stefanie Andrea Erika Held ◽  
Solveig Daecke ◽  
Annkristin Heine ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Activation ◽  
Inflammatory Responses ◽  
Nuclear Factor Κb ◽  
Mitogen Activated Protein Kinase ◽  
Peroxisome Proliferator ◽  
Nuclear Factor ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Mitogen Activated Protein

Abstract Dectin-1 is the major receptor for fungal β-glucans. The activation of Dectin-1 leads to the up-regulation of surface molecules on dendritic cells (DCs) and cytokine secretion. Furthermore, Dectin-1 is important for the recruitment of leukocytes and the production of inflammatory mediators. Peroxisome proliferator–activated receptor-γ (PPAR-γ) and its ligands, cyclopentenone prostaglandins or thiazolidinediones, have modulatory effects on B-cell, T-cell, and DC function. In the present study, we analyzed the effects of troglitazone (TGZ), a high-affinity synthetic PPAR-γ ligand, on the Dectin-1–mediated activation of monocyte-derived human DCs. Dectin-1–mediated activation of DCs was inhibited by TGZ, as shown by down-regulation of costimulatory molecules and reduced secretion of cytokines and chemokines involved in T-lymphocyte activation. Furthermore, TGZ inhibited the T-cell–stimulatory capacity of DCs. These effects were not due to a diminished expression of Dectin-1 or to a reduced phosphorylation of spleen tyrosine kinase; they were mediated by the inhibition of downstream signaling molecules such as mitogen-activated protein kinases and nuclear factor-κB. Furthermore, curdlan-mediated accumulation of caspase recruitment domain 9 (CARD9) in the cytosol was inhibited by TGZ. Our data demonstrate that the PPAR-γ ligand TGZ inhibits Dectin-1–mediated activation by interfering with CARD9, mitogen-activated protein kinase, and nuclear factor-κB signaling pathways. This confirms their important role as negative-feedback regulators of potentially harmful inflammatory responses.

scholarly journals Retinoids increase human apolipoprotein A-11 expression through activation of the retinoid X receptor but not the retinoic acid receptor.

1996 ◽  
Vol 16 (7) ◽  
pp. 3350-3360 ◽  
Author(s):  
N Vu-Dac ◽  
K Schoonjans ◽  
V Kosykh ◽  
J Dallongeville ◽  
R A Heyman ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Primary Cultures ◽  
Retinoid X Receptor ◽  
Site Directed Mutagenesis ◽  
Transcriptional Level ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Reporter Construct ◽  
Response Element ◽  
Peroxisome Proliferator Activated Receptor

Considering the link between plasma high-density lipoprotein (HDL) cholesterol levels and a protective effect against coronary artery disease as well as the suggested beneficial effects of retinoids on the production of the major HDL apolipoprotein (apo), apo A-I, the goal of this study was to analyze the influence of retinoids on the expression of apo A-II, the other major HDL protein. Retinoic acid (RA) derivatives have a direct effect on hepatic apo A-II production, since all-trans (at) RA induces apo A-II mRNA levels and apo A-II secretion in primary cultures of human hepatocytes. In the HepG2 human hepatoblastoma cell line, both at-RA and 9-cis RA as well as the retinoid X receptor (RXR)-specific agonist LGD 1069, but not the RA receptor (RAR) agonist ethyl-p-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-l-pro penyl]-benzoic acid (TTNPB), induce apo A-II mRNA levels. Transient-transfection experiments with a reporter construct driven by the human apo A-II gene promoter indicated that 9-cis RA and at-RA, as well as the RXR agonists LGD 1069 and LG 100268, induced apo A-II gene expression at the transcriptional level. Only minimal effects of the RAR agonist TTNPB were observed on the apo A-II promoter reporter construct. Unilateral deletions and site-directed mutagenesis identified the J site of the apo A-II promoter mediating the responsiveness to RA. This element contains two imperfect half-sites spaced by 1 oligonucleotide. Cotransfection assays in combination with the use of RXR or RAR agonists showed that RXR but not RAR transactivates the apo A-II promoter through this element. By contrast, RAR inhibits the inductive effects of RXR on the apo A-II J site in a dose-dependent fashion. Gel retardation assays demonstrated that RXR homodimers bind, although with a lower affinity than RAR-RXR heterodimers, to the AH-RXR response element. In conclusion, retinoids induce hepatic apo A-II production at the transcriptional level via the interaction of RXR with an element in the J site containing two imperfect half-sites spaced by 1 oligonucleotide, thereby demonstrating an important role of RXR in controlling human lipoprotein metabolism. Since the J site also confers responsiveness of the apo A-II gene to fibrates and fatty acids via the activation of peroxisome proliferator-activated receptor-RXR heterodimers, this site can be considered a plurimetabolic response element.

scholarly journals The 5,7-Dimethoxyflavone Suppresses Sarcopenia by Regulating Protein Turnover and Mitochondria Biogenesis-Related Pathways

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1079 ◽  
Author(s):  
Changhee Kim ◽  
Jae-Kwan Hwang
Keyword(s):  
Muscle Mass ◽  
Protein Turnover ◽  
Inflammatory Responses ◽  
Biological Activities ◽  
Muscle Disease ◽  
Initiation Factor ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Necrosis Factor Alpha ◽  
Peroxisome Proliferator Activated Receptor

Sarcopenia is a muscle disease featured by the loss of muscle mass and dysfunction with advancing age. The 5,7-dimethoxyflavone (DMF), a major flavone found in Kaempferia parviflora, has biological activities, including anti-diabetes, anti-obesity, and anti-inflammation. However, its anti-sarcopenic effect remains to be elucidated. This current study investigated the inhibitory activity of DMF on sarcopenia. Eighteen-month-old mice were orally administered DMF at the dose of 25 mg·kg−1·day−1 or 50 mg·kg−1·day−1 for 8 weeks. DMF not only stimulated grip strength and exercise endurance but also increased muscle mass and volume. Besides, DMF stimulated the phosphatidylinositol 3-kinase-Akt pathway, consequently activating the mammalian target of rapamycin-eukaryotic initiation factor 4E-binding protein 1-70-kDa ribosomal protein S6 kinase pathway for protein synthesis. DMF reduced the mRNA expression of E3 ubiquitin ligase- and autophagy-lysosomal-related genes involved in proteolysis via the phosphorylation of Forkhead box O3. DMF upregulated peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, nuclear respiratory factor 1, and mitochondrial transcription factor A along with the increase of relative mitochondrial DNA content. DMF alleviated inflammatory responses by reducing the tumor necrosis factor-alpha and interleukin-6 serum and mRNA levels. Collectively, DMF can be used as a natural agent to inhibit sarcopenia via improving protein turnover and mitochondria function.

scholarly journals Macrophage activation induces formation of the anti-inflammatory lipid cholesteryl-nitrolinoleate

2008 ◽  
Vol 417 (1) ◽  
pp. 223-238 ◽  
Author(s):  
Ana M. Ferreira ◽  
Mariana I. Ferrari ◽  
Andrés Trostchansky ◽  
Carlos Batthyany ◽  
José M. Souza ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Macrophage Activation ◽  
Inflammatory Responses ◽  
Nuclear Factor Κb ◽  
Interferon Γ ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Inflammatory Stimuli ◽  
Anti Inflammatory ◽  
Electrophilic Reactivity

Nitroalkene derivatives of fatty acids act as adaptive, anti-inflammatory signalling mediators, based on their high-affinity PPARγ (peroxisome-proliferator-activated receptor γ) ligand activity and electrophilic reactivity with proteins, including transcription factors. Although free or esterified lipid nitroalkene derivatives have been detected in human plasma and urine, their generation by inflammatory stimuli has not been reported. In the present study, we show increased nitration of cholesteryl-linoleate by activated murine J774.1 macrophages, yielding the mononitrated nitroalkene CLNO2 (cholesteryl-nitrolinoleate). CLNO2 levels were found to increase ∼20-fold 24 h after macrophage activation with Escherichia coli lipopolysaccharide plus interferon-γ; this response was concurrent with an increase in the expression of NOS2 (inducible nitric oxide synthase) and was inhibited by the •NO (nitric oxide) inhibitor L-NAME (NG-nitro-L-arginine methyl ester). Macrophage (J774.1 and bone-marrow-derived cells) inflammatory responses were suppressed when activated in the presence of CLNO2 or LNO2 (nitrolinoleate). This included: (i) inhibition of NOS2 expression and cytokine secretion through PPARγ and •NO-independent mechanisms; (ii) induction of haem oxygenase-1 expression; and (iii) inhibition of NF-κB (nuclear factor κB) activation. Overall, these results suggest that lipid nitration occurs as part of the response of macrophages to inflammatory stimuli involving NOS2 induction and that these by-products of nitro-oxidative reactions may act as novel adaptive down-regulators of inflammatory responses.

scholarly journals Protective Effects of Salidroside on Mitochondrial Functions against Exertional Heat Stroke-Induced Organ Damage in the Rat

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Zhang ◽  
Ming Peng ◽  
Yang Yang ◽  
Zhangwu Xiao ◽  
Bin Song ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Multiorgan Failure ◽  
Heat Stroke ◽  
Organ Damage ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Protective Effects ◽  
Exertional Heat Stroke ◽  
Peroxisome Proliferator Activated Receptor ◽  
Mitochondrial Functions

Exertional heat stroke (EHS) results in a constellation of systemic inflammatory responses resulting in multiorgan failure and an extremely high mortality. The present study was designed to evaluate the protective effects of salidroside on EHS by improving mitochondrial functions in the rat model. Liver and heart mitochondria were observed by transmission electron microscopy and mitochondrial membrane potential (ΔΨm) was detected by a fluorescent probe. Intramitochondrial free Ca2+concentration, mitochondrial respiratory control ratio (RCR), reactive oxygen species (ROS) levels, superoxide dismutase (SOD), and malondialdehyde (MDA) activity were detected by the corresponding kits. RT-PCR was performed to estimate peroxisome proliferator-activated receptor-γcoactivator-1α(PGC-1α) and manganese form of SOD (MnSOD) mRNA expression. The results demonstrated that salidroside was able to relieve EHS damage by reducing the swelling of mitochondria, ROS levels, and MDA activity, as well as increasing ΔΨm, RCR, free Ca2+concentration, SOD, PGC-1α, and MnSOD mRNA levels. In conclusion, salidroside has protective effects on mitochondrial functions against exertional heat stroke-induced organ damage in the rat.

scholarly journals Peroxisomal-proliferator-activated receptor alpha activates transcription of the rat hepatic malonyl-CoA decarboxylase gene: a key regulation of malonyl-CoA level

2004 ◽  
Vol 378 (3) ◽  
pp. 983-990 ◽  
Author(s):  
Gha Young LEE ◽  
Nam Hee KIM ◽  
Zheng-Shan ZHAO ◽  
Bong Soo CHA ◽  
Y. Sam KIM
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Retinoid X Receptor ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Mobility Shift ◽  
Peroxisome Proliferator Activated Receptor ◽  
Malonyl Coa ◽  
Promoter Deletion Analysis

MCD (malonyl-CoA decarboxylase), which catalyses decarboxylation of malonyl-CoA, is known to play an important role in the regulation of malonyl-CoA concentration. Recently, it has been observed that the expression of MCD is significantly decreased in the hearts of the PPARα (peroxisome-proliferator-activated receptor α) (−/−) mice, where the rate of fatty-acid oxidation is decreased by the increased malonyl-CoA level [Campbell, Kozak, Wagner, Altarejos, Dyck, Belke, Severson, Kelly and Lopaschuk (2002) J. Biol. Chem. 277, 4098–4103]. This suggests that MCD may be transcriptionally regulated by PPARα. To investigate whether PPARα is truly responsible for transcriptional regulation of the rat MCD gene, transient reporter assay was performed in CV-1 cells. The promoter activity was increased by 17-fold in CV-1 cells co-transfected with PPARα/retinoid X receptor α expression plasmid. In sequence analysis of the promoter region, three putative PPREs (PPAR response elements) were identified, and promoter deletion analysis showed that PPRE2 and PPRE3 were functional. Electrophoretic mobility-shift assays revealed that PPARα/retinoid X receptor α heterodimer indeed bound to the two PPREs, and the binding specificity of PPARα on PPRE was also confirmed by experiments with mutated oligonucleotides. These results indicate that the elements behaved as a responsive site to PPARα activation. MCD mRNA levels in WY14643-treated rat hepatoma cells as well as in the liver of fenofibrate-fed Otsuka Long-Evans Tokushima fatty rats were also found to be increased, suggesting that PPARα can activate the rat hepatic MCD transcription by binding to the PPREs in the promoter. We propose that MCD performs an important role in understanding the regulatory mechanism between activated PPARα and fatty-acid oxidation by altering the malonyl-CoA concentration.

scholarly journals Peroxisome proliferator–activated receptor (PPAR)α expression in T cells mediates gender differences in development of T cell–mediated autoimmunity

2007 ◽  
Vol 204 (2) ◽  
pp. 321-330 ◽  
Author(s):  
Shannon E. Dunn ◽  
Shalina S. Ousman ◽  
Raymond A. Sobel ◽  
Luis Zuniga ◽  
Sergio E. Baranzini ◽  
...  
Keyword(s):  
Gender Differences ◽  
T Cell ◽  
Inflammatory Responses ◽  
Clinical Signs ◽  
Nuclear Factor Κb ◽  
Interferon Γ ◽  
Interleukin 17 ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Genetic Ablation

Peroxisome proliferator–activated receptor (PPAR)α is a nuclear receptor that mediates gender differences in lipid metabolism. PPARα also functions to control inflammatory responses by repressing the activity of nuclear factor κB (NF-κB) and c-jun in immune cells. Because PPARα is situated at the crossroads of gender and immune regulation, we hypothesized that this gene may mediate sex differences in the development of T cell–mediated autoimmune disease. We show that PPARα is more abundant in male as compared with female CD4+ cells and that its expression is sensitive to androgen levels. Genetic ablation of this gene selectively removed the brake on NF-κB and c-jun activity in male T lymphocytes, resulting in higher production of interferon γ and tumor necrosis factor (but not interleukin 17), and lower production of T helper (Th)2 cytokines. Upon induction of experimental autoimmune encephalomyelitis, male but not female PPARα−/− mice developed more severe clinical signs that were restricted to the acute phase of disease. These results suggest that males are less prone to develop Th1-mediated autoimmunity because they have higher T cell expression of PPARα.

Sign in / Sign up

Export Citation Format

Share Document