scholarly journals Vanin-1 licenses inflammatory mediator production by gut epithelial cells and controls colitis by antagonizing peroxisome proliferator-activated receptor γ activity

2006 ◽  
Vol 203 (13) ◽  
pp. 2817-2827 ◽  
Author(s):  
Carole Berruyer ◽  
Laurent Pouyet ◽  
Virginie Millet ◽  
Florent M. Martin ◽  
Aude LeGoffic ◽  
...  

Colitis involves immune cell–mediated tissue injuries, but the contribution of epithelial cells remains largely unclear. Vanin-1 is an epithelial ectoenzyme with a pantetheinase activity that provides cysteamine/cystamine to tissue. Using the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-colitis model we show here that Vanin-1 deficiency protects from colitis. This protection is reversible by administration of cystamine or bisphenol A diglycidyl ether, a peroxisome proliferator-activated receptor (PPAR)γ antagonist. We further demonstrate that Vanin-1, by antagonizing PPARγ, licenses the production of inflammatory mediators by intestinal epithelial cells. We propose that Vanin-1 is an epithelial sensor of stress that exerts a dominant control over innate immune responses in tissue. Thus, the Vanin-1/pantetheinase activity might be a new target for therapeutic intervention in inflammatory bowel disease.


2011 ◽  
Vol 301 (3) ◽  
pp. G547-G554 ◽  
Author(s):  
Kechen Ban ◽  
Julie M. Sprunt ◽  
Stephanie Martin ◽  
Peiying Yang ◽  
Rosemary A. Kozar

Glutamine possesses gut-protective effects both clinically and in the laboratory. We have shown in a rodent model of mesenteric ischemia-reperfusion that enteral glutamine increased peroxisome proliferator-activated receptor-γ (PPAR-γ) and was associated with a reduction in mucosal injury and inflammation. The mechanism by which glutamine activates PPAR-γ is unknown, and we hypothesized that it was via a ligand-dependent mechanism. Intestinal epithelial cells, IEC-6, were co-transfected with PPAR-γ response element-luciferase promoter/reporter construct. Cells were pretreated with increasing concentrations of glutamine ± GW9662 (a specific antagonist of PPAR-γ) and analyzed for PPAR-γ response element luciferase activity as an indicator of PPAR-γ activation. PPAR-γ nuclear activity was assessed by electrophoretic mobility shift assay. Cell lysates were subjected to tandem mass spectroscopy for measurement of prostaglandin and lipoxygenase metabolites. A time- and concentration-dependent increase in PPAR-γ transcriptional activity, but not mRNA or protein, was demonstrated. Activity was abrogated by the PPAR-γ inhibitor, GW9662, and changes in activity correlated with PPAR-γ nuclear binding. Glutamine, via degradation to glutamate, activated the metabolic by-products of the lipoxygenase and linoleic acid pathways, 15-S-hydroxyeicosatetraenoic acid and dehydrogenated 13-hydroxyoctaolecadienoic acid, known endogenous PPAR-γ ligands in the small bowel. This novel mechanism may explain the gut-protective effects of enteral glutamine.



2002 ◽  
Vol 362 (3) ◽  
pp. 573-578 ◽  
Author(s):  
Sebastian FEHLBERG ◽  
Stefan TRAUTWEIN ◽  
Alexandra GÖKE ◽  
Rüdiger GÖKE

Peroxisome proliferator-activated receptors (PPARs) are nuclear transcription factors which are involved in many biological processes, such as regulation of cell differentiation, lipid metabolism, inflammation and cell death. PPARs consist of three families, PPAR-α, PPAR-δ and PPAR-γ. Bisphenol A diglycidyl ether (BADGE) has been described as a pure antagonist of PPAR-γ. However, recent data also revealed PPAR-γ-agonistic activities of BADGE. Here we show that BADGE kills transformed cells by apoptosis and promotes the cytotoxic effects of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and indomethacin. The cytotoxic effect of BADGE does not require PPAR-γ expression and is mediated in caspase-dependent and caspase-independent manners.



Author(s):  
Jing Li ◽  
Kewei Xu ◽  
Hao Ding ◽  
Qiaozhen Xi

Abstract Aims Increasing preclinical and clinical reports have demonstrated the efficacy of gabapentin (GBP) in treating alcohol use disorder (AUD). However, the mechanism of the effects of GBP in AUD is largely unknown. Herein, we sought to investigate the effect of GBP in a rat model of AUD and explore the underlying mechanism. Methods The intermittent access to 20% ethanol in a 2-bottle choice (IA2BC) procedure was exploited to induce high voluntary ethanol consumption in rats. The rats were treated daily for 20 days with different doses of GBP, simultaneously recording ethanol/water intake. The locomotor activity and grooming behavior of rats were also tested to evaluate the potential effects of GBP on confounding motor in rats. The levels of IL-1β and TNF-α in serum and hippocampus homogenate from the rats were detected by using ELISA. The expressions of peroxisome proliferator-activated-receptor γ (PPAR-γ) and nuclear factor-κB (NF-κB) in the hippocampus were determined by immunofluorescence and western blot. Results GBP reduced alcohol consumption, whereas increased water consumption and locomotor activity of rats. GBP was also able to decrease the levels of IL-1β and TNF-α in both serum and hippocampus, in addition to the expression of NF-κB in the hippocampus. Furthermore, these effects attributed to GBP were observed to disappear in the presence of bisphenol A diglycidyl ether (BADGE), a specific inhibitor of PPAR-γ. Conclusions Our findings revealed that GBP could activate PPAR-γ to suppress the NF-κB signaling pathway, contributing to the decrease of ethanol consumption and ethanol-induced neuroimmune responses.



Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1386 ◽  
Author(s):  
Danyelle M. Liddle ◽  
Meaghan E. Kavanagh ◽  
Amanda J. Wright ◽  
Lindsay E. Robinson

Adipose tissue (AT) expansion induces local hypoxia, a key contributor to the chronic low-grade inflammation that drives obesity-associated disease. Apple flavonols phloretin (PT) and phlorizin (PZ) are suggested anti-inflammatory molecules but their effectiveness in obese AT is inadequately understood. Using in vitro models designed to reproduce the obese AT microenvironment, 3T3-L1 adipocytes were cultured for 24 h with PT or PZ (100 μM) concurrent with the inflammatory stimulus lipopolysaccharide (LPS; 10 ng/mL) and/or the hypoxia mimetic cobalt chloride (CoCl2; 100 μM). Within each condition, PT was more potent than PZ and its effects were partially mediated by peroxisome proliferator-activated receptor (PPAR)-γ (p < 0.05), as tested using the PPAR-γ antagonist bisphenol A diglycidyl ether (BADGE). In LPS-, CoCl2-, or LPS + CoCl2-stimulated adipocytes, PT reduced mRNA expression and/or secreted protein levels of inflammatory and macrophage chemotactic adipokines, and increased that of anti-inflammatory and angiogenic adipokines, which was consistent with reduced mRNA expression of M1 polarization markers and increased M2 markers in RAW 264.7 macrophages cultured in media collected from LPS + CoCl2-simulated adipocytes (p < 0.05). Further, within LPS + CoCl2-stimulated adipocytes, PT reduced reactive oxygen species accumulation, nuclear factor-κB activation, and apoptotic protein expression (p < 0.05). Overall, apple flavonols attenuate critical aspects of the obese AT phenotype.



2017 ◽  
Vol 95 (6) ◽  
pp. 641-646 ◽  
Author(s):  
Ola Ahmed El-Gohary ◽  
Mona Maher Allam

Infarct-like lesion induced by isoprenaline is a well-known model to study myocardial infarction (MI). Vitamin D has been shown to have anti-inflammatory and antioxidant effects. Recent studies highlighted cross talk between vitamin D and peroxisome proliferator-activated receptor gamma (PPAR-γ). The present study was designed to investigate the effect of pretreatment with vitamin D on the isoprenaline-induced infarct-like lesion in rats and the role of PPAR-γ as a novel mechanism in vitamin-D-mediated cardioprotective effect. Markers chosen to assess cardiac damage included serum level of creatine kinase (CK), lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). Cardiac contents of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH) were also assessed. Furthermore, ECG monitoring and measurement of injury extension were carried out. Isoprenaline increased the level of cardiac enzymes, as well as inflammatory and oxidative stress biomarkers. In addition, it produced ST-segment elevation. Pretreatment with vitamin D significantly improved previous parameters. The prior treatment with bisphenol A diglycidyl ether (BADGE), a PPAR-γ antagonist, significantly attenuated the protective effect of vitamin D. In conclusion, vitamin D can be demonstrated as a promising cardioprotective agent in MI and PPAR-γ significantly contributes toward vitamin-D-mediated protection.





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