scholarly journals Expression of peroxisome proliferator-activated receptor-γ in macrophage suppresses experimentally induced colitis

2007 ◽  
Vol 292 (2) ◽  
pp. G657-G666 ◽  
Author(s):  
Yatrik M. Shah ◽  
Keiichirou Morimura ◽  
Frank J. Gonzalez

Peroxisome proliferator-activated receptor-γ (PPAR-γ) has been shown to be a protective transcription factor in mouse models of inflammatory bowel disease (IBD). PPAR-γ is expressed in several different cell types, and mice with a targeted disruption of the PPAR-γ gene in intestinal epithelial cells demonstrated increased susceptibility to dextran sulfate sodium (DSS)-induced IBD. However, the highly selective PPAR-γ ligand rosiglitazone decreased the severity of DSS-induced colitis and suppressed cytokine production in both PPAR-γ intestinal specific null mice and wild-type littermates. Therefore the role of PPAR-γ in different tissues and their contribution to the pathogenesis of IBD still remain unclear. Mice with a targeted disruption of PPAR-γ in macrophages (PPAR-γΔMφ) and wild-type littermates (PPAR-γF/F) were administered 2.5% DSS in drinking water to induce IBD. Typical clinical symptoms were evaluated on a daily basis, and proinflammatory cytokine analysis was performed. PPAR-γΔMφ mice displayed an increased susceptibility to DSS-induced colitis compared with wild-type littermates, as defined by body weight loss, diarrhea, rectal bleeding score, colon length, and histology. IL-1β, CCR2, MCP-1, and inducible nitric oxide synthase mRNA levels in colons of PPAR-γΔMφ mice treated with DSS were higher than in similarly treated PPAR-γF/F mice. The present study has identified a novel protective role for macrophage PPAR-γ in the DSS-induced IBD model. The data suggest that PPAR-γ regulates recruitment of macrophages to inflammatory foci in the colon.

2000 ◽  
Vol 20 (14) ◽  
pp. 5119-5128 ◽  
Author(s):  
Jeffrey M. Peters ◽  
Susanna S. T. Lee ◽  
Wen Li ◽  
Jerrold M. Ward ◽  
Oksana Gavrilova ◽  
...  

ABSTRACT To determine the physiological roles of peroxisome proliferator-activated receptor β (PPARβ), null mice were constructed by targeted disruption of the ligand binding domain of the murine PPARβ gene. Homozygous PPARβ-null term fetuses were smaller than controls, and this phenotype persisted postnatally. Gonadal adipose stores were smaller, and constitutive mRNA levels of CD36 were higher, in PPARβ-null mice than in controls. In the brain, myelination of the corpus callosum was altered in PPARβ-null mice. PPARβ was not required for induction of mRNAs involved in epidermal differentiation induced byO-tetradecanoylphorbol-13-acetate (TPA). The hyperplastic response observed in the epidermis after TPA application was significantly greater in the PPARβ-null mice than in controls. Inflammation induced by TPA in the skin was lower in wild-type mice fed sulindac than in similarly treated PPARβ-null mice. These results are the first to provide in vivo evidence of significant roles for PPARβ in development, myelination of the corpus callosum, lipid metabolism, and epidermal cell proliferation.


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4995
Author(s):  
Su Ji Bae ◽  
Ji Eun Kim ◽  
Yun Ju Choi ◽  
Su Jin Lee ◽  
Jeong Eun Gong ◽  
...  

The efficacy of α-cubebenoate isolated from Schisandra chinensis has been previously studied in three disease areas, namely inflammation, sepsis, and allergy, and its role in other diseases is still being explored. To identify the novel function of α-cubebenoate on lipid metabolism and related inflammatory response, alterations in fat accumulation, lipogenesis, lipolysis, and inflammasome activation were measured in 3T3-L1 preadipocytes and primary adipocytes treated with α-cubebenoate. Lipid accumulation significantly decreased in MDI (3-isobutyl-1-methylxanthine, dexamethasone, and insulin)-stimulated 3T3-L1 adipocytes treated with α-cubebenoate without any significant cytotoxicity. The mRNA levels of peroxisome proliferator-activated receptor (PPAR)γ and CCAAT-enhancer binding protein (C/EBP) α for adipogenesis, as well as adipocyte fatty acid binding protein 2 (aP2) and fatty acid synthetase (FAS) for lipogenesis, were reduced after α-cubebenoate treatment, while cell cycle arrest at G2/M stage was restored in the same group. α-cubebenoate treatment induced glycerol release in primary adipocytes and enhanced expression of lipolytic proteins (HSL, perilipin, and ATGL) expression in MDI-stimulated 3T3-L1 adipocytes. Inflammasome activation and downstream cytokines expression were suppressed with α-cubebenoate treatment, but the expression of insulin receptor signaling factors was remarkably increased by α-cubebenoate treatment in MDI-stimulated 3T3-L1 adipocytes. These results indicate that α-cubebenoate may play a novel role as lipogenesis inhibitor, lipolysis stimulator, and inflammasome suppressor in MDI-stimulated 3T3-L1 adipocytes. Our results provide the possibility that α-cubebenoate can be considered as one of the candidates for obesity management.


2003 ◽  
Vol 81 (10) ◽  
pp. 979-985 ◽  
Author(s):  
Yaoting Gui ◽  
Josef V Silha ◽  
Suresh Mishra ◽  
Liam J Murphy

We investigated the changes in insulin resistance and adipose tissue expression of the adipokines resistin, adiponectin, and leptin and the transcription factors peroxisome proliferator-activated receptor-γ (PPAR-γ) and retinoid X receptor-α (RXR-α) during 48 h of food deprivation. Insulin sensitivity (SI) declined, whereas glucose effectiveness (SG) increased. Plasma adiponectin levels declined in the first 8 h and remained constant thereafter. There was no correlation between either SI or SG and adiponectin protein or mRNA levels. PPAR-γ mRNA abundance remained constant, whereas leptin and resistin mRNAs and plasma leptin declined and RXR-α mRNA abundance increased in both white and brown fat. Leptin mRNA abundance was closely correlated with SI (R2 = 0.91 and 0.87 for white and brown fat, respectively). Resistin mRNA abundance correlated inversely with SG (R2 = 0.99 and 0.84 for white and brown fat, respectively). These data indicate that changes in the expression of leptin are more closely correlated with the insulin resistance of fasting than with changes in other adipokines or RXR-α and PPAR-γ expression.Key words: insulin resistance, fasting, adipokines, resistin, leptin, adiponectin.


2005 ◽  
Vol 288 (4) ◽  
pp. C899-C905 ◽  
Author(s):  
Jinah Hwang ◽  
Dean J. Kleinhenz ◽  
Bernard Lassègue ◽  
Kathy K. Griendling ◽  
Sergey Dikalov ◽  
...  

Recently, we demonstrated that the peroxisome proliferator-activated receptor-γ (PPAR-γ) ligands, either 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) or ciglitazone, increased endothelial nitric oxide (·NO) release without altering endothelial nitric oxide synthase (eNOS) expression ( 4 ). However, the precise molecular mechanisms of PPAR-γ-stimulated endothelial·NO release remain to be defined. Superoxide anion radical (O2−·) combines with ·NO to decrease·NO bioavailability. NADPH oxidase, which produces O2−·, and Cu/Zn-superoxide dismutase (Cu/Zn-SOD), which degrades O2−·, thereby contribute to regulation of endothelial cell·NO metabolism. Therefore, we examined the ability of PPAR-γ ligands to modulate endothelial O2−· metabolism through alterations in the expression and activity of NADPH oxidase or Cu/Zn-SOD. Treatment with 10 μM 15d-PGJ2 or ciglitazone for 24 h decreased human umbilical vein endothelial cell (HUVEC) membrane NADPH-dependent O2−· production detected with electron spin resonance spectroscopy. Treatment with 15d-PGJ2 or ciglitazone also reduced relative mRNA levels of the NADPH oxidase subunits, nox-1, gp91 phox (nox-2), and nox-4, as measured using real-time PCR analysis. Concordantly, Western blot analysis demonstrated that 15d-PGJ2 or ciglitazone decreased nox-2 and nox-4 protein expression. PPAR-γ ligands also stimulated both activity and expression of Cu/Zn-SOD in HUVEC. These data suggest that in addition to any direct effects on endothelial·NO production, PPAR-γ ligands enhance endothelial·NO bioavailability, in part by altering endothelial O2−· metabolism through suppression of NADPH oxidase and induction of Cu/Zn-SOD. These findings further elucidate the molecular mechanisms by which PPAR-γ ligands directly alter vascular endothelial function.


2008 ◽  
Vol 18 (2) ◽  
pp. 329-338 ◽  
Author(s):  
W. Wu ◽  
J. Celestino ◽  
M. R. Milam ◽  
K. M. Schmeler ◽  
R. R. Broaddus ◽  
...  

PTEN mutations have been implicated in the development of endometrial hyperplasia and subsequent cancer. Peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists have demonstrated antineoplastic and chemopreventive effects. The purpose of this study was to evaluate the effects of the PPAR-γ agonist rosiglitazone on both PTEN wild type and PTEN null cell lines and in the PTEN heterozygote(+/−) murine model. Hec-1-A (PTEN wild type) and Ishikawa (PTEN null) cells were treated with rosiglitazone. Thirty-five female PTEN+/− mice were genotyped and placed into one of four groups for treatment for 18 weeks: A) PTEN wild type with 4 mg/kg rosiglitazone, B) PTEN+/− mice with vehicle, C) PTEN+/− mice with 4 mg/kg rosiglitazone, and D) PTEN+/− mice with 8 mg/kg rosiglitazone. Proliferation and apoptosis were measured by bromodeoxyuridine (BrdU) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling of DNA fragmentation sites assay. Rosiglitazone caused cell growth inhibition in both Hec-1-A and Ishikawa in a dose-dependent manner (P< 0.02 and P< 0.03, respectively). Rosiglitazone also induced apoptosis in both Hec-1-A (P< .001) and Ishikawa (P< .001) cells in a dose-dependent manner. In the murine model, rosiglitazone decreased proliferation of the endometrial hyperplastic lesions (B vs C; 39.7% vs 9.3% and B vs D; 39.7% vs 4.2%; P< 0.0001) and increased apoptosis of glandular endometrial epithelial cells (B vs C; 2.8% vs 22.4%; P< 0.0001 and B vs D; 2.8% vs 30.2%; P= 0.003). PPAR-γ agonist rosiglitazone inhibits proliferation and induces apoptosis in both PTEN intact and PTEN null cancer cell lines and in hyperplastic endometrial lesions in the PTEN+/− murine model.


2005 ◽  
Vol 385 (2) ◽  
pp. 469-477 ◽  
Author(s):  
Biao LU ◽  
Yan J. JIANG ◽  
Yaling ZHOU ◽  
Fred Y. XU ◽  
Grant M. HATCH ◽  
...  

AGPAT (1-acyl-sn-glycerol 3-phosphate acyltransferase) exists in at least five isoforms in humans, termed as AGPAT1, AGPAT2, AGPAT3, AGPAT4 and AGPAT5. Although they catalyse the same biochemical reaction, their relative function, tissue expression and regulation are poorly understood. Linkage studies in humans have revealed that AGPAT2 contributes to glycerolipid synthesis and plays an important role in regulating lipid metabolism. We report the molecular cloning, tissue distribution, and enzyme characterization of mAGPATs (murine AGPATs) and regulation of cardiac mAGPATs by PPARα (peroxisome-proliferator-activated receptor α). mAGPATs demonstrated differential tissue expression profiles: mAGPAT1 and mAGPAT3 were ubiquitously expressed in most tissues, whereas mAGPAT2, mAGPAT4 and mAGPAT5 were expressed in a tissue-specific manner. mAGPAT2 expressed in in vitro transcription and translation reactions and in transfected COS-1 cells exhibited specificity for 1-acyl-sn-glycerol 3-phosphate. When amino acid sequences of five mAGPATs were compared, three highly conserved motifs were identified, including one novel motif/pattern KX2LX6GX12R. Cardiac mAGPAT activities were 25% lower (P<0.05) in PPARα null mice compared with wild-type. In addition, cardiac mAGPAT activities were 50% lower (P<0.05) in PPARα null mice fed clofibrate compared with clofibrate fed wild-type animals. This modulation of AGPAT activity was accompanied by significant enhancement/reduction of the mRNA levels of mAGPAT3/mAGPAT2 respectively. Finally, mRNA expression of cardiac mAGPAT3 appeared to be regulated by PPARα activation. We conclude that cardiac mAGPAT activity may be regulated by both the composition of mAGPAT isoforms and the levels of each isoform.


2014 ◽  
Vol 306 (1) ◽  
pp. H26-H32 ◽  
Author(s):  
Tamas Kriska ◽  
Cody Cepura ◽  
Kathryn M. Gauthier ◽  
William B. Campbell

Targeted disruption of the Alox15 gene makes mice resistant to angiotensin II-, DOCA/salt-, and Nω-nitro-l-arginine methyl ester (l-NAME)-induced experimental hypertension. Macrophages, a primary source of Alox15, are facilitating this resistance, but the underlying mechanism is not known. Because Alox15 metabolites are peroxisome proliferator-activated receptor (PPAR)γ agonists, we hypothesized that activation of macrophage PPARγ is the key step in Alox15 mediation of hypertension. Thioglycollate, used for macrophage elicitation, selectively upregulated PPARγ and its target gene CD36 in peritoneal macrophages of both wild-type (WT) and Alox15−/− mice. Moreover, thioglycollate-injected Alox15−/− mice became hypertensive upon l-NAME treatment. A similar hypertensive effect was observed with adoptive transfer of thioglycollate-elicited Alox15−/− macrophages into Alox15−/− recipient mice. The role of PPARγ was further specified by using the selective PPARγ antagonist GW9662. WT mice treated with 50 μg/kg daily dose of GW9662 for 12 days became resistant to l-NAME-induced hypertension. The PPARγ antagonist treatment also prevented l-NAME-induced hypertension in thioglycollate-injected Alox15−/− mice, indicating a PPARγ-mediated effect in macrophage elicitation and the resultant hypertension. These results indicate a regulatory role for macrophage-localized PPARγ in l-NAME-induced experimental hypertension.


2003 ◽  
Vol 369 (3) ◽  
pp. 539-547 ◽  
Author(s):  
Tineke KOK ◽  
Vincent W. BLOKS ◽  
Henk WOLTERS ◽  
Rick HAVINGA ◽  
Peter L.M. JANSEN ◽  
...  

Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor that controls expression of genes involved in lipid metabolism and is activated by fatty acids and hypolipidaemic fibrates. Fibrates induce the hepatic expression of murine multidrug resistance 2 (Mdr2), encoding the canalicular phospholipid translocator. The physiological role of PPARα in regulation of Mdr2 and other genes involved in bile formation is unknown. We found no differences in hepatic expression of the ATP binding cassette transporter genes Mdr2, Bsep (bile salt export pump), Mdr1a/1b, Abca1 and Abcg5/Abcg8 (implicated in cholesterol transport), the bile salt-uptake systems Ntcp (Na+-taurocholate co-transporting polypeptide gene) and Oatp1 (organic anion-transporting polypeptide 1 gene) or in bile formation between wild-type and Pparα(-/-) mice. Upon treatment of wild-type mice with ciprofibrate (0.05%, w/w, in diet for 2 weeks), the expression of Mdr2 (+3-fold), Mdr1a (+6-fold) and Mdr1b (+11-fold) mRNAs was clearly induced, while that of Oatp1 (-5-fold) was reduced. Mdr2 protein levels were increased, whereas Bsep, Ntcp and Oatp1 were drastically decreased. Exposure of cultured wild-type mouse hepatocytes to PPARα agonists specifically induced Mdr2 mRNA levels and did not affect expression of Mdr1a/1b. Altered transporter expression in fibrate-treated wild-type mice was associated with a 400% increase in bile flow: secretion of phospholipids and cholesterol was increased only during high-bile-salt infusions. No fibrate effects were observed in Pparα(-/-) mice. In conclusion, our results show that basal bile formation is not affected by PPARα deficiency in mice. The induction of Mdr2 mRNA and Mdr2 protein levels by fibrates is mediated by PPARα, while the induction of Mdr1a/1b in vivo probably reflects a secondary phenomenon related to chronic PPARα activation.


2018 ◽  
Vol 49 (11) ◽  
pp. 1859-1868 ◽  
Author(s):  
Karen M. Ryan ◽  
Ian Patterson ◽  
Declan M. McLoughlin

AbstractBackgroundThe transcriptional coactivator peroxisome proliferator-activated receptor-γ coactivator (PGC-1α), termed the ‘master regulator of mitochondrial biogenesis’, has been implicated in stress and resilience to stress-induced depressive-like behaviours in animal models. However, there has been no study conducted to date to examine PGC-1α levels in patients with depression or in response to antidepressant treatment. Our aim was to assess PGC-1α mRNA levels in blood from healthy controls and patients with depression pre-/post-electroconvulsive therapy (ECT), and to examine the relationship between blood PGC-1α mRNA levels and clinical symptoms and outcomes with ECT.MethodsWhole blood PGC-1α mRNA levels were analysed in samples from 67 patients with a major depressive episode and 70 healthy controls, and in patient samples following a course of ECT using quantitative real-time polymerase chain reaction (qRT-PCR). Exploratory subgroup correlational analyses were carried out to determine the relationship between PGC-1α and mood scores.ResultsPGC-1α levels were lower in patients with depression compared with healthy controls (p = 0.03). This lower level was predominantly accounted for by patients with psychotic unipolar depression (p = 0.004). ECT did not alter PGC-1α levels in the depressed group as a whole, though exploratory analyses revealed a significant increase in PGC-1α in patients with psychotic unipolar depression post-ECT (p = 0.045). We found no relationship between PGC-1α mRNA levels and depression severity or the clinical response to ECT.ConclusionsPGC-1α may represent a novel therapeutic target for the treatment of depression, and be a common link between various pathophysiological processes implicated in depression.


2005 ◽  
Vol 201 (8) ◽  
pp. 1205-1215 ◽  
Author(s):  
Christel Rousseaux ◽  
Bruno Lefebvre ◽  
Laurent Dubuquoy ◽  
Philippe Lefebvre ◽  
Olivier Romano ◽  
...  

5-aminosalicylic acid (5-ASA) is an antiinflammatory drug widely used in the treatment of inflammatory bowel diseases. It is known to inhibit the production of cytokines and inflammatory mediators, but the mechanism underlying the intestinal effects of 5-ASA remains unknown. Based on the common activities of peroxisome proliferator–activated receptor-γ (PPAR-γ) ligands and 5-ASA, we hypothesized that this nuclear receptor mediates 5-ASA therapeutic action. To test this possibility, colitis was induced in heterozygous PPAR-γ+/− mice and their wild-type littermates, which were then treated with 5-ASA. 5-ASA treatment had a beneficial effect on colitis only in wild-type and not in heterozygous mice. In epithelial cells, 5-ASA increased PPAR-γ expression, promoted its translocation from the cytoplasm to the nucleus, and induced a modification of its conformation permitting the recruitment of coactivators and the activation of a peroxisome-proliferator response element–driven gene. Validation of these results was obtained with organ cultures of human colonic biopsies. These data identify PPAR-γ as a target of 5-ASA underlying antiinflammatory effects in the colon.


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