scholarly journals Ligand-activated peroxisome proliferator-activated receptor-δ and -γ inhibit lipopolysaccharide-primed release of high mobility group box 1 through upregulation of SIRT1

2014 ◽  
Vol 5 (10) ◽  
pp. e1432-e1432 ◽  
Author(s):  
J S Hwang ◽  
W J Lee ◽  
E S Kang ◽  
S A Ham ◽  
T Yoo ◽  
...  
Keyword(s):  
High Mobility ◽  
High Mobility Group ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Abstract 3608: High Mobility Group A1 Protein - A New Regulator for Peroxisome Proliferator-Activated Receptor Gamma Transcriptional Repression in Human Aortic Smooth Muscle Cells

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Mandy Bloch ◽  
Anna Foryst-Ludwig ◽  
Thomas Unger ◽  
Ulrich Kintscher
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gene Transcription ◽  
Promoter Activity ◽  
High Mobility ◽  
Muscle Cells ◽  
High Mobility Group ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Aortic Smooth Muscle

The study aimed to identify new nuclear cofactors for PPARgamma (peroxisome proliferator-activated receptor gamma)-dependent gene transcription in human aortic smooth muscle cells (HASMC) in order to develop new PPARgamma-ligands with improved clinical safety in the absence of deleterious cardiovascular side effects. Using an Oligo GEArray® Human Nuclear Receptors and Coregulators Microarray for gene expression profiling, we identified the transcriptional regulator and chromatin modifying High Mobility Group (HMG) A1 protein highly expressed in unstimulated HASMC. PPARgamma-dependent gene regulation was studied by analysis of PMA-induced MMP-9 (matrix metalloproteinase 9) expression ± pioglitazone (pio 10μM). PMA (50ng/ml) stimulated MMP-9 mRNA expression by 46.3±22.3-fold (p<0.05 vs. vehicle) which was markedly blocked by pio (10μM: 17.4±4.8-fold vs. PMA alone p<0.05). Pio also blocked PMA-induced MMP-9 promoter activity by 45% in transactivation assays in HEK293 using a pGL3-MMP-9 2.2 kb construct. To evaluate the role of HMGA1, gene silencing experiments with siRNA for HMGA1 were performed (91 % in HASMC and 80.2% in HEK293 reduction of HMGA1 protein expression). HMGA1 siRNA completely abolished PPARgamma-mediated MMP9-mRNA repression (control siRNA: pio-mediated MMP-9 regulation vs. PMA alone: −66.8 % in HASMC and −59.3% in HEK293 p<0.01; HMGA1 siRNA: pio-mediated MMP-9 regulation vs. PMA alone: +10.7 % in HASMC and +14.7% in HEK293 vs. PMA alone; p=n.s.). Knockdown of HMGA1 expression reverse trans-repression of MMP9 by PPARgamma in HASMCs. By using ChIP assay we could demonstrate that pio-induced PPARgamma activation leads to a potent recruitment of PPARgamma (3.0 fold vs.1.15 fold PMA alone) and HMGA1 complexes (1.24 fold vs. 0.0 fold PMA alone) to the MMP9 promoter in HASMC. In consonance with reduced promoter activity, RNA-Polymerase II was removed from the MMP9 promoter by pio (0.08 fold vs 1.04 fold PMA alone). In conclusion, HMGA1 is required for PPARgamma-mediated repression of MMP-9 gene transcription. Ligand-induced HMGA1-PPARgamma interactions might be an important determinant for ligand-specific anti-atherosclerotic actions.

scholarly journals Formononetin inhibits lipopolysaccharide-induced release of high mobility group box 1 by upregulating SIRT1 in a PPARδ-dependent manner

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4208 ◽  
Author(s):  
Jung Seok Hwang ◽  
Eun Sil Kang ◽  
Sung Gu Han ◽  
Dae-Seog Lim ◽  
Kyung Shin Paek ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Specific Inhibitor ◽  
High Mobility ◽  
Inhibitory Effect ◽  
Sirtuin 1 ◽  
High Mobility Group ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Sirt1 Expression

Background The release of high mobility group box 1 (HMGB1) induced by inflammatory signals acts as a cellular alarmin to trigger a chain of inflammatory responses. Although the inflammatory actions of HMGB1 are well studied, less is known about the therapeutic agents that can impede its release. This study investigated whether the isoflavonoid formononetin can modulate HMGB1 release in cellular inflammatory responses. Methods RAW264.7 murine macrophages were exposed to lipopolysaccharide (LPS) in the presence or absence of formononetin. The levels of HMGB1 release, sirtuin 1 (SIRT1) expression, and HMGB1 acetylation were analyzed by immunoblotting and real-time polymerase chain reaction. The effects of resveratrol and sirtinol, an activator and inhibitor of SIRT1, respectively, on LPS-induced HMGB1 release were also evaluated. Results Formononetin modulated cellular inflammatory responses by suppressing the release of HMGB1 by macrophages exposed to LPS. In RAW264.7 cells, formononetin significantly attenuated LPS-induced release of HMGB1 into the extracellular environment, which was accompanied by a reduction in its translocation from the nucleus to the cytoplasm. In addition, formononetin significantly induced mRNA and protein expression of SIRT1 in a peroxisome proliferator-activated receptor δ (PPARδ)-dependent manner. These effects of formononetin were dramatically attenuated in cells treated with small interfering RNA (siRNA) against PPARδ or with GSK0660, a specific inhibitor of PPARδ, indicating that PPARδ is involved in formononetin-mediated SIRT1 expression. In line with these effects, formononetin-mediated inhibition of HMGB1 release in LPS-treated cells was reversed by treatment with SIRT1-targeting siRNA or sirtinol, a SIRT1 inhibitor. By contrast, resveratrol, a SIRT1 activator, further potentiated the inhibitory effect of formononetin on LPS-induced HMGB1 release, revealing a possible mechanism by which formononetin regulates HMGB1 release through SIRT1. Furthermore, modulation of SIRT1 expression by transfection of SIRT1- or PPARδ-targeting siRNA significantly counteracted the inhibitory effects of formononetin on LPS-induced HMGB1 acetylation, which was responsible for HMGB1 release. Discussion This study shows for the first time that formononetin inhibits HMGB1 release by decreasing HMGB1 acetylation via upregulating SIRT1 in a PPARδ-dependent manner. Formononetin consequently exhibits anti-inflammatory activity. Identification of agents, such as formononetin, which can block HMGB1 release, may help to treat inflammation-related disorders.

scholarly journals Fenofibrate increases the expression of high mobility group AT-hook 2 (HMGA2) gene and induces adipocyte differentiation of orbital fibroblasts from Graves' ophthalmopathy

2004 ◽  
Vol 33 (1) ◽  
pp. 133-143 ◽  
Author(s):  
D Pasquali ◽  
GM Pierantoni ◽  
A Fusco ◽  
S Staibano ◽  
V Colantuoni ◽  
...  
Keyword(s):  
Adipocyte Differentiation ◽  
High Mobility ◽  
Nuclear Hormone Receptor ◽  
High Mobility Group ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Graves Ophthalmopathy ◽  
Before And After ◽  
High Level ◽  
Orbital Fibroblasts

Expansion of adipose tissue in the orbits is a key feature of Graves' ophthalmopathy. Recent evidence shows that orbital fibroblasts are committed to differentiate into adipocytes under appropriate stimuli. Rosiglitazone, an agonist of the nuclear hormone receptor, peroxisome proliferator-activated receptor gamma (PPARgamma) is able to induce both differentiation of orbital fibroblasts into mature adipocytes and expression of the TSH receptor (TSHr) gene. Several studies have suggested an important role of the high mobility group AT-hook 2 (HMGA2) gene in adipocytic cell growth and development. To investigate further the association between adipogenesis-related genes and orbital fibroblasts, we treated fibroblasts from Graves' ophthalmopathy (FGOs) and from normal orbital tissues with fenofibrate, a specific agonist for PPARalpha. We then evaluated the expression of the PPARalpha, PPARgamma2, HMGA2, leptin and TSHr genes before and after 24 h of fenofibrate treatment, using semiquantitative and real-time PCR. For up to 96 h after exposure to fenofibrate, FGOs differentiated into adipocytes. PPARalpha and PPARgamma2 were expressed more in FGOs than in normal cultures, whereas TSHr mRNA was detected only in FGOs. Expression of HMGA2 mRNA and protein was significantly increased in FGOs from 6 to 24 h after fenofibrate, confirming its role in the early phase of adipocyte differentiation. Treatment with fenofibrate for 24 h significantly increased the expression of leptin and TSHr genes. Moreover, TSH treatment significantly increased the accumulation of cAMP, demonstrating that FGOs express functional TSHr. The high level of expression of PPARalpha other than PPARgamma2 transcripts and the stimulating effect of fenofibrate on adipogenesis and on HMGA2, leptin and TSHr genes also indicate that the PPARalpha pathway plays an important part in the adipocyte differentiation of FGOs. These findings suggest that novel drugs to antagonize PPARalpha, other than the PPARgamma signalling system, may also need to be considered in the treatment or prevention of Graves' ophthalmopathy.

scholarly journals Activation of Peroxisome Proliferator-Activated Receptorγby Rosiglitazone Inhibits Lipopolysaccharide-Induced Release of High Mobility Group Box 1

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Jung Seok Hwang ◽  
Eun Sil Kang ◽  
Sun Ah Ham ◽  
Taesik Yoo ◽  
Hanna Lee ◽  
...  
Keyword(s):  
Cellular Response ◽  
Survival Rates ◽  
High Mobility ◽  
Inhibitory Effect ◽  
High Mobility Group ◽  
Raw 264.7 Cells ◽  
Signal Molecules ◽  
Peroxisome Proliferator ◽  
Treatment And Prevention ◽  
Peroxisome Proliferator Activated Receptors

Peroxisome proliferator-activated receptors (PPARs) are shown to modulate the pathological status of sepsis by regulating the release of high mobility group box 1 (HMGB1), a well-known late proinflammatory mediator of sepsis. Ligand-activated PPARs markedly inhibited lipopolysaccharide- (LPS) induced release of HMGB1 in RAW 264.7 cells. Among the ligands of PPAR, the effect of rosiglitazone, a specific ligand for PPARγ, was superior in the inhibition of HMGB1 release induced by LPS. This effect was observed in cells that received rosiglitazone before LPS or after LPS treatment, indicating that rosiglitazone is effective in both treatment and prevention. Ablation of PPARγwith small interfering RNA or GW9662-mediated inhibition of PPARγabolished the effect of rosiglitazone on HMGB1 release. Furthermore, the overexpression of PPARγmarkedly potentiated the inhibitory effect of rosiglitazone on HMGB1 release. In addition, rosiglitazone inhibited LPS-induced expression of Toll-like receptor 4 signal molecules, suggesting a possible mechanism by which rosiglitazone modulates HMGB1 release. Notably, the administration of rosiglitazone to mice improved survival rates in an LPS-induced animal model of endotoxemia, where reduced levels of circulating HMGB1 were demonstrated. Taken together, these results suggest that PPARs play an important role in the cellular response to inflammation by inhibiting HMGB1 release.

scholarly journals HMGB1 Is Involved in the Protective Effect of the PPARαAgonist Fenofibrate against Cardiac Hypertrophy

PPAR Research ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Zhankui Jia ◽  
Rui Xue ◽  
Gangqiong Liu ◽  
Ling Li ◽  
Jinjian Yang ◽  
...  
Keyword(s):  
Cardiac Hypertrophy ◽  
Nuclear Dna ◽  
Inflammatory Responses ◽  
High Mobility ◽  
Peroxisome Proliferator ◽  
Protective Effects ◽  
Inhibitory Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Hmgb1 Expression ◽  
Potential Strategy

High mobility group box 1 (HMGB1) is a ubiquitous nuclear DNA-binding protein whose function is dependent on its cellular location. Extracellular HMGB1 is regarded as a delayed mediator of proinflammatory cytokines for initiating and amplifying inflammatory responses, whereas nuclear HMGB1 has been found to prevent cardiac hypertrophy and heart failure. Because fenofibrate, a peroxisome proliferator-activated receptorα(PPARα) agonist, has shown both protective effects against cardiac hypertrophy and inhibitory effects against inflammation, the potential modulation of HMGB1 expression and secretion by fenofibrate is of great interest. We herein provide evidence that fenofibrate modulates basal and LPS-stimulated HMGB1 expression and localization in addition to secretion of HMGB1 in cardiomyocytes. In addition, administration of fenofibrate to mice prevented the development of cardiac hypertrophy induced by thoracic transverse aortic constriction (TAC) while increasing levels of nuclear HMGB1. Altogether, these data suggest that fenofibrate may inhibit the development of cardiac hypertrophy by regulating HMGB1 expression, which provides a new potential strategy to treat cardiac hypertrophy.

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