scholarly journals Peroxisome proliferator–activated receptor γ (PPARγ) induces the gene expression of integrin αVβ5 to promote macrophage M2 polarization

2018 ◽  
Vol 293 (43) ◽  
pp. 16572-16582 ◽  
Author(s):  
Qinyu Yao ◽  
Jia Liu ◽  
Zihui Zhang ◽  
Fan Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Foam Cell ◽  
Human Peripheral Blood ◽  
Luciferase Reporter ◽  
Foam Cell Formation ◽  
Marker Genes ◽  
Peroxisome Proliferator ◽  
Blood Monocytes ◽  
Peroxisome Proliferator Activated Receptor ◽  
M2 Polarization

Peroxisome proliferator–activated receptor γ (PPARγ) is a member of the nuclear receptor superfamily and polarizes the macrophages into an anti-inflammatory M2 state. Integrins are transmembrane receptors that drive various cellular functions, including monocyte adhesion and foam cell formation. In this study, we first reported that the expression of integrins αV and β5 was up-regulated by PPARγ activation in RAW264.7 cells and human peripheral blood monocytes. Luciferase reporter and ChIP assay revealed that PPARγ directly bound to the potential PPAR-responsive elements sites in the 5′-flanking regions of both murine and human integrin αV and β5 genes, respectively. In addition, we showed that PPARγ augmented the ligation of integrins αV and β5. Knockdown of integrin αVβ5 by siRNA strategy or treatment with cilengitide, a potent inhibitor of integrin αVβ5, attenuated PPARγ-induced expression of Ym1 (chitinase-like protein 3), Arg1 (Arginase1), Fizz1 (resistin-like molecule RELMα), and other M2 marker genes, suggesting that the heterodimers of integrin αVβ5 were involved in PPARγ-induced M2 polarization. In conclusion, these results provided novel evidence that PPARγ-mediated gene expression and the ensuing ligation of integrins αV and β5 are implicated in macrophage M2 polarization.

scholarly journals A meta-analysis study of gene expression datasets in mouse liver under PPARα knockout

2013 ◽  
Vol 95 (2-3) ◽  
pp. 78-88 ◽  
Author(s):  
KAN HE ◽  
ZHEN WANG ◽  
QISHAN WANG ◽  
YUCHUN PAN
Keyword(s):  
Gene Expression ◽  
Mouse Liver ◽  
Meta Analysis ◽  
Expression Patterns ◽  
Hepatic Tissue ◽  
Marker Genes ◽  
Specific Marker ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Microarray Datasets

SummaryGene expression profiling of peroxisome-proliferator-activated receptor α (PPARα) has been used in several studies, but there were no consistent results on gene expression patterns involved in PPARα activation in genome-wide due to different sample sizes or platforms. Here, we employed two published microarray datasets both PPARα dependent in mouse liver and applied meta-analysis on them to increase the power of the identification of differentially expressed genes and significantly enriched pathways. As a result, we have improved the concordance in identifying many biological mechanisms involved in PPARα activation. We suggest that our analysis not only leads to more identified genes by combining datasets from different resources together, but also provides some novel hepatic tissue-specific marker genes related to PPARα according to our re-analysis.

scholarly journals Fenofibrate Reduces the Severity of Neuroretinopathy in a Type 2 Model of Diabetes without Inducing Peroxisome Proliferator-Activated Receptor Alpha-Dependent Retinal Gene Expression

2020 ◽  
Vol 10 (1) ◽  
pp. 126
Author(s):  
Jennifer M. Enright ◽  
Sheng Zhang ◽  
Christina Thebeau ◽  
Emily Siebert ◽  
Alexander Jin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Elevated Serum ◽  
Oscillatory Potentials ◽  
Luciferase Reporter ◽  
Peroxisome Proliferator ◽  
Serum Triglycerides ◽  
Peroxisome Proliferator Activated Receptor ◽  
Receptor Alpha ◽  
Peroxisome Proliferator Response Element

Fenofibrate slows the progression of clinical diabetic retinopathy (DR), but its mechanism of action in the retina remains unclear. Fenofibrate is a known agonist of peroxisome proliferator-activated receptor alpha (PPARα), a transcription factor critical for regulating metabolism, inflammation and oxidative stress. Using a DR mouse model, db/db, we tested the hypothesis that fenofibrate slows early DR progression by activating PPARα in the retina. Relative to healthy littermates, six-month-old db/db mice exhibited elevated serum triglycerides and cholesterol, retinal gliosis, and electroretinography (ERG) changes including reduced b-wave amplitudes and delayed oscillatory potentials. These pathologic changes in the retina were improved by oral fenofibrate. However, fenofibrate did not induce PPARα target gene expression in whole retina or isolated Müller glia. The capacity of the retina to respond to PPARα was further tested by delivering the PPARα agonist GW590735 to the intraperitoneal or intravitreous space in mice carrying the peroxisome proliferator response element (PPRE)-luciferase reporter. We observed strong induction of the reporter in the liver, but no induction in the retina. In summary, fenofibrate treatment of db/db mice prevents the development of early DR but is not associated with induction of PPARα in the retina.

scholarly journals Regulatory effects of aggregated LDL on apoptosis during foam cell formation of human peripheral blood monocytes

FEBS Letters ◽  
1997 ◽  
Vol 409 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Nobuhiko Kubo ◽  
Jiro Kikuchi ◽  
Yusuke Furukawa ◽  
Toshihiko Sakai ◽  
Hatsunori Ohta ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Foam Cell ◽  
Human Peripheral Blood ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Blood Monocytes ◽  
Peripheral Blood Monocytes ◽  
Regulatory Effects

scholarly journals Regulation of Macrophage Cholesterol Efflux through Hydroxymethylglutaryl-CoA Reductase Inhibition

2005 ◽  
Vol 280 (23) ◽  
pp. 22212-22221 ◽  
Author(s):  
Carmen A. Argmann ◽  
Jane Y. Edwards ◽  
Cynthia G. Sawyez ◽  
Caroline H. O'Neil ◽  
Robert A. Hegele ◽  
...  
Keyword(s):  
Cholesterol Efflux ◽  
Foam Cell ◽  
Cell Formation ◽  
Dominant Negative ◽  
Foam Cell Formation ◽  
Peroxisome Proliferator ◽  
Very Low Density Lipoproteins ◽  
Peroxisome Proliferator Activated Receptor ◽  
Abca1 Expression ◽  
Coa Reductase

The cholesterol biosynthetic pathway produces numerous signaling molecules. Oxysterols through liver X receptor (LXR) activation regulate cholesterol efflux, whereas the non-sterol mevalonate metabolite, geranylgeranyl pyrophosphate (GGPP), was recently demonstrated to inhibit ABCA1 expression directly, through antagonism of LXR and indirectly through enhanced RhoA geranylgeranylation. We used HMG-CoA reductase inhibitors (statins) to test the hypothesis that reduced synthesis of mevalonate metabolites would enhance cholesterol efflux and attenuate foam cell formation. Preincubation of THP-1 macrophages with atorvastatin, dose dependently (1–10 μm) stimulated cholesterol efflux to apolipoprotein AI (apoAI, 10–60%, p < 0.05) and high density lipoprotein (HDL3) (2–50%, p < 0.05), despite a significant decrease in cholesterol synthesis (2–90%). Atorvastatin also increased ABCA1 and ABCG1 mRNA abundance (30 and 35%, p < 0.05). Addition of mevalonate, GGPP or farnesyl pyrophosphate completely blocked the statin-induced increase in ABCA1 expression and apoAI-mediated cholesterol efflux. A role for RhoA was established, because two inhibitors of Rho protein activity, a geranylgeranyl transferase inhibitor and C3 exoenzyme, increased cholesterol efflux to apoAI (20–35%, p < 0.05), and macrophage expression of dominant-negative RhoA enhanced cholesterol efflux to apoAI (20%, p < 0.05). In addition, atorvastatin increased the RhoA levels in the cytosol fraction and decreased the membrane localization of RhoA. Atorvastatin treatment activated peroxisome proliferator activated receptor γ and increased LXR-mediated gene expression suggesting that atorvastatin induces cholesterol efflux through a molecular cascade involving inhibition of RhoA signaling, leading to increased peroxisome proliferator activated receptor γ activity, enhanced LXR activation, increased ABCA1 expression, and cholesterol efflux. Finally, statin treatment inhibited cholesteryl ester accumulation in macrophages challenged with atherogenic hypertriglyceridemic very low density lipoproteins indicating that statins can regulate foam cell formation.

The Anti-Atherogenic Properties of Sesamin are Mediated via Improved Macrophage Cholesterol Efflux Through PPARγ1-LXRα and MAPK Signaling

2014 ◽  
Vol 84 (1-2) ◽  
pp. 79-91 ◽  
Author(s):  
Amin F. Majdalawieh ◽  
Hyo-Sung Ro
Keyword(s):  
Cholesterol Efflux ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Foam Cell ◽  
Mapk Signaling ◽  
Luciferase Reporter ◽  
Foam Cell Formation ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Macrophage Cholesterol Efflux

Background: Foam cell formation resulting from disrupted macrophage cholesterol efflux, which is triggered by PPARγ1 and LXRα, is a hallmark of atherosclerosis. Sesamin and sesame oil exert anti-atherogenic effects in vivo. However, the exact molecular mechanisms underlying such effects are not fully understood. Aim: This study examines the potential effects of sesamin (0, 25, 50, 75, 100 μM) on PPARγ1 and LXRα expression and transcriptional activity as well as macrophage cholesterol efflux. Methods: PPARγ1 and LXRα expression and transcriptional activity are assessed by luciferase reporter assays. Macrophage cholesterol efflux is evaluated by ApoAI-specific cholesterol efflux assays. Results: The 50 μM, 75 μM, and 100 μM concentrations of sesamin up-regulated the expression of PPARγ1 (p< 0.001, p < 0.001, p < 0.001, respectively) and LXRα (p = 0.002, p < 0.001, p < 0.001, respectively) in a concentration-dependent manner. Moreover, 75 μM and 100 μM concentrations of sesamin led to 5.2-fold (p < 0.001) and 6.0-fold (p<0.001) increases in PPAR transcriptional activity and 3.9-fold (p< 0.001) and 4.2-fold (p < 0.001) increases in LXR transcriptional activity, respectively, in a concentration- and time-dependent manner via MAPK signaling. Consistently, 50 μM, 75 μM, and 100 μM concentrations of sesamin improved macrophage cholesterol efflux by 2.7-fold (p < 0.001), 4.2-fold (p < 0.001), and 4.2-fold (p < 0.001), respectively, via MAPK signaling. Conclusion: Our findings shed light on the molecular mechanism(s) underlying sesamin’s anti-atherogenic effects, which seem to be due, at least in part, to its ability to up-regulate PPARγ1 and LXRα expression and transcriptional activity, improving macrophage cholesterol efflux. We anticipate that sesamin may be used as a therapeutic agent for treating atherosclerosis.

scholarly journals Glucose-Dependent Insulinotropic Polypeptide Suppresses Foam Cell Formation of Macrophages through Inhibition of the Cyclin-Dependent Kinase 5-CD36 Pathway

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 832
Author(s):  
Michishige Terasaki ◽  
Hironori Yashima ◽  
Yusaku Mori ◽  
Tomomi Saito ◽  
Yoshie Shiraga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Foam Cell ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
U937 Cells ◽  
Cyclin Dependent Kinase ◽  
Macrophage Foam Cell ◽  
Cyclin Dependent Kinase 5 ◽  
Gip Receptor ◽  
Cd36 Gene

Glucose-dependent insulinotropic polypeptide (GIP) has been reported to have an atheroprotective property in animal models. However, the effect of GIP on macrophage foam cell formation, a crucial step of atherosclerosis, remains largely unknown. We investigated the effects of GIP on foam cell formation of, and CD36 expression in, macrophages extracted from GIP receptor-deficient (Gipr−/−) and Gipr+/+ mice and cultured human U937 macrophages by using an agonist for GIP receptor, [D-Ala2]GIP(1–42). Foam cell formation evaluated by esterification of free cholesterol to cholesteryl ester and CD36 gene expression in macrophages isolated from Gipr+/+ mice infused subcutaneously with [D-Ala2]GIP(1–42) were significantly suppressed compared with vehicle-treated mice, while these beneficial effects were not observed in macrophages isolated from Gipr−/− mice infused with [D-Ala2]GIP(1–42). When macrophages were isolated from Gipr+/+ and Gipr−/− mice, and then exposed to [D-Ala2]GIP(1–42), similar results were obtained. [D-Ala2]GIP(1–42) attenuated ox-LDL uptake of, and CD36 gene expression in, human U937 macrophages as well. Gene expression level of cyclin-dependent kinase 5 (Cdk5) was also suppressed by [D-Ala2]GIP(1–42) in U937 cells, which was corelated with that of CD36. A selective inhibitor of Cdk5, (R)-DRF053 mimicked the effects of [D-Ala2]GIP(1–42) in U937 cells. The present study suggests that GIP could inhibit foam cell formation of macrophages by suppressing the Cdk5-CD36 pathway via GIP receptor.

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