scholarly journals DNMT1-mediated PPARα methylation aggravates damage of retinal tissues in diabetic retinopathy mice

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Ying Zhu ◽  
Xinru Wang ◽  
Xiaoyun Zhou ◽  
Lexi Ding ◽  
Dan Liu ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Dna Methyltransferase ◽  
Cell Model ◽  
Underlying Mechanism ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Retinal Tissue ◽  
Specific Pcr ◽  
Gene And Protein Expression ◽  
Retinal Capillary

Abstract Background Peroxisome proliferator-activated receptor alpha (PPARα) is associated with diabetic retinopathy (DR), and the underlying mechanism is still unclear. Aim of this work was to investigate the mechanism of PPARα in DR. Methods Human retinal capillary pericytes (HRCPs) were treated with high glucose (HG) to induce DR cell model. DR mouse model was established by streptozotocin injection, and then received 5-Aza-2-deoxycytidine (DAC; DNA methyltransferase inhibitor) treatment. Hematoxylin–eosin staining was performed to assess retinal tissue damage. PPARα methylation was examined by Methylation-Specific PCR. Flow cytometry and DCFH-DA fluorescent probe was used to estimate apoptosis and reactive oxygen species (ROS). The interaction between DNA methyltransferase-1 (DNMT1) and PPARα promoter was examined by Chromatin Immunoprecipitation. Quantitative real-time PCR and western blot were performed to assess gene and protein expression. Results HG treatment enhanced the methylation levels of PPARα, and repressed PPARα expression in HRCPs. The levels of apoptotic cells and ROS were significantly increased in HRCPs in the presence of HG. Moreover, DNMT1 was highly expressed in HG-treated HRCPs, and DNMT1 interacted with PPARα promoter. PPARα overexpression suppressed apoptosis and ROS levels of HRCPs, which was rescued by DNMT1 up-regulation. In DR mice, DAC treatment inhibited PPARα methylation and reduced damage of retinal tissues. Conclusion DNMT1-mediated PPARα methylation promotes apoptosis and ROS levels of HRCPs and aggravates damage of retinal tissues in DR mice. Thus, this study may highlight novel insights into DR pathogenesis.

Gabapentin Reduces Alcohol Intake in Rats by Regulating NF-κB Signaling Pathway Via PPAR γ

2021 ◽  
Author(s):  
Jing Li ◽  
Kewei Xu ◽  
Hao Ding ◽  
Qiaozhen Xi
Keyword(s):  
Locomotor Activity ◽  
Signaling Pathway ◽  
Specific Inhibitor ◽  
Underlying Mechanism ◽  
Ethanol Consumption ◽  
Diglycidyl Ether ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ ◽  
Tnf Α

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.

scholarly journals Anxa2 gene silencing attenuates obesity-induced insulin resistance by suppressing the NF-κB signaling pathway

2019 ◽  
Vol 316 (2) ◽  
pp. C223-C234 ◽  
Author(s):  
Yong Wang ◽  
Yun-Sheng Cheng ◽  
Xiao-Qiang Yin ◽  
Gang Yu ◽  
Ben-Li Jia
Keyword(s):  
Insulin Resistance ◽  
Gene Silencing ◽  
Signaling Pathway ◽  
Nuclear Translocation ◽  
Cell Model ◽  
Global Scale ◽  
Differentially Expressed ◽  
Cytokine Signaling ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor

Insulin resistance (IR) continues to pose a major threat to public health due to its role in the pathogenesis of metabolic syndrome and its ever-increasing prevalence on a global scale. The aim of the current study was to investigate the efficacy of Anxa2 in obesity-induced IR through the mediation of the NF-κB signaling pathway. Microarray analysis was performed to screen differentially expressed genes associated with obesity. To verify whether Anxa2 was differentially expressed in IR triggered by obesity, IR mouse models were established in connection with a high-fat diet (HFD). In the mouse IR model, the role of differentially expressed Anxa2 in glycometabolism and IR was subsequently detected. To investigate the effect of Anxa2 on IR and its correlation with inflammation, a palmitic acid (PA)-induced IR cell model was established, with the relationship between Anxa2 and the NF-κB signaling pathway investigated accordingly. Anxa2 was determined to be highly expressed in IR. Silencing Anxa2 was shown to inhibit IR triggered by obesity. When Anxa2 was knocked down, elevated expression of phosphorylated insulin receptor substrate 1 (IRS1), IRS1 and peroxisome proliferator-activated receptor coactivator-1a, and glucose tolerance and insulin sensitivity along with 2-deoxy-d-glucose uptake was detected, whereas decreased expression of suppressor of cytokine signaling 3, IL-6, IL-1β, TNF-α, and p50 was observed. Taken together, the current study ultimately demonstrated that Anxa2 may be a novel drug strategy for IR disruption, indicating that Anxa2 gene silencing is capable of alleviating PA or HFD-induced IR and inflammation through its negative regulatory role in the process of p50 nuclear translocation of the NF-κB signaling pathway.

scholarly journals Central leptin regulates heart lipid content by selectively increasing PPAR β/δ expression

2018 ◽  
Vol 236 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Cristina Mora ◽  
Cristina Pintado ◽  
Blanca Rubio ◽  
Lorena Mazuecos ◽  
Virginia López ◽  
...  
Keyword(s):  
Target Genes ◽  
Cardiac Tissue ◽  
Cardiac Metabolism ◽  
Pyruvate Dehydrogenase Kinase ◽  
Hormone Sensitive Lipase ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Expression Of Genes ◽  
Gene And Protein Expression ◽  
Tag Accumulation

The role of central leptin in regulating the heart from lipid accumulation in lean leptin-sensitive animals has not been fully elucidated. Herein, we investigated the effects of central leptin infusion on the expression of genes involved in cardiac metabolism and its role in the control of myocardial triacylglyceride (TAG) accumulation in adult Wistar rats. Intracerebroventricular (icv) leptin infusion (0.2 µg/day) for 7 days markedly decreased TAG levels in cardiac tissue. Remarkably, the cardiac anti-steatotic effects of central leptin were associated with the selective upregulation of gene and protein expression of peroxisome proliferator-activated receptor β/δ (PPARβ/δ, encoded by Pparb/d) and their target genes, adipose triglyceride lipase (encoded by Pnpla2, herefater referred to as Atgl), hormone sensitive lipase (encoded by Lipe, herefater referred to as Hsl), pyruvate dehydrogenase kinase 4 (Pdk4) and acyl CoA oxidase 1 (Acox1), involved in myocardial intracellular lipolysis and mitochondrial/peroxisomal fatty acid utilization. Besides, central leptin decreased the expression of stearoyl-CoA deaturase 1 (Scd1) and diacylglycerol acyltransferase 1 (Dgat1) involved in TAG synthesis and increased the CPT-1 independent palmitate oxidation, as an index of peroxisomal β-oxidation. Finally, the pharmacological inhibition of PPARβ/δ decreased the effects on gene expression and cardiac TAG content induced by leptin. These results indicate that leptin, acting at central level, regulates selectively the cardiac expression of PPARβ/δ, contributing in this way to regulate the cardiac TAG accumulation in rats, independently of its effects on body weight.

scholarly journals Characterization of a Novel Polymorphism in PPARG Regulatory Region Associated with Type 2 Diabetes and Diabetic Retinopathy in Italy

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Valerio Costa ◽  
Amelia Casamassimi ◽  
Katherine Esposito ◽  
Angela Villani ◽  
Mariaelena Capone ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Diabetic Retinopathy ◽  
Direct Sequencing ◽  
Regulatory Region ◽  
Vascular Complications ◽  
Proliferative Retinopathy ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Significant Difference

Peroxisome proliferator-activated receptor gamma polymorphisms have been widely associated with type 2 diabetes, although their role in the pathogenesis of vascular complications is not yet demonstrated. In this study, a cohort of 211 type 2 diabetes, 205 obese, and 254 control individuals was genotyped for Pro12Ala, C1431T, C-2821T polymorphisms, and for a newly identified polymorphism (A-2819G). The above-mentioned polymorphisms were analyzed by gene-specific PCR and direct sequencing of all samples. A significant difference was found for -2819G frequency when patients with type 2 diabetes—particularly diabetic women with the proliferative retinopathy—were compared with healthy control individuals. In conclusion, we identified a novel polymorphism, A-2819G, inPPARGgene, and we found it to be associated with type 2 diabetes and proliferative retinopathy in diabetic females. In the analyzed population, this variant represents a genetic risk factor for developing the diabetic retinopathy, whereas Pro12Ala and C1431T do not.

scholarly journals PPARγ1 attenuates cytosol to membrane translocation of PKCα to desensitize monocytes/macrophages

2007 ◽  
Vol 176 (5) ◽  
pp. 681-694 ◽  
Author(s):  
Andreas von Knethen ◽  
Mathias Soller ◽  
Nico Tzieply ◽  
Andreas Weigert ◽  
Axel M. Johann ◽  
...  
Keyword(s):  
Human Monocyte ◽  
Underlying Mechanism ◽  
Nuclear Factor Κb ◽  
Peroxisome Proliferator ◽  
Membrane Translocation ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Protein Interaction ◽  
Tnf Α ◽  
Dependent Inhibition ◽  
Pparγ Agonists

Recently, we provided evidence that PKCα depletion in monocytes/macrophages contributes to cellular desensitization during sepsis. We demonstrate that peroxisome proliferator–activated receptor γ (PPARγ) agonists dose dependently block PKCα depletion in response to the diacylglycerol homologue PMA in RAW 264.7 and human monocyte–derived macrophages. In these cells, we observed PPARγ-dependent inhibition of nuclear factor-κB (NF-κB) activation and TNF-α expression in response to PMA. Elucidating the underlying mechanism, we found PPARγ1 expression not only in the nucleus but also in the cytoplasm. Activation of PPARγ1 wild type, but not an agonist-binding mutant of PPARγ1, attenuated PMA-mediated PKCα cytosol to membrane translocation. Coimmunoprecipitation assays pointed to a protein–protein interaction of PKCα and PPARγ1, which was further substantiated using a mammalian two-hybrid system. Applying PPARγ1 mutation and deletion constructs, we identified the hinge helix 1 domain of PPARγ1 that is responsible for PKCα binding. Therefore, we conclude that PPARγ1-dependent inhibition of PKCα translocation implies a new model of macrophage desensitization.

scholarly journals Endocrine-Disrupting Organotin Compounds Are Potent Inducers of Adipogenesis in Vertebrates

2006 ◽  
Vol 20 (9) ◽  
pp. 2141-2155 ◽  
Author(s):  
Felix Grün ◽  
Hajime Watanabe ◽  
Zamaneh Zamanian ◽  
Lauren Maeda ◽  
Kayo Arima ◽  
...  
Keyword(s):  
Steroid Receptors ◽  
Cell Model ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Affinity Ligand ◽  
Tributyltin Chloride ◽  
Environmental Agents ◽  
Adipose Mass

Abstract Dietary and xenobiotic compounds can disrupt endocrine signaling, particularly of steroid receptors and sexual differentiation. Evidence is also mounting that implicates environmental agents in the growing epidemic of obesity. Despite a long-standing interest in such compounds, their identity has remained elusive. Here we show that the persistent and ubiquitous environmental contaminant, tributyltin chloride (TBT), induces the differentiation of adipocytes in vitro and increases adipose mass in vivo. TBT is a dual, nanomolar affinity ligand for both the retinoid X receptor (RXR) and the peroxisome proliferator-activated receptor γ (PPARγ). TBT promotes adipogenesis in the murine 3T3-L1 cell model and perturbs key regulators of adipogenesis and lipogenic pathways in vivo. Moreover, in utero exposure to TBT leads to strikingly elevated lipid accumulation in adipose depots, liver, and testis of neonate mice and results in increased epididymal adipose mass in adults. In the amphibian Xenopus laevis, ectopic adipocytes form in and around gonadal tissues after organotin, RXR, or PPARγ ligand exposure. TBT represents, to our knowledge, the first example of an environmental endocrine disrupter that promotes adipogenesis through RXR and PPARγ activation. Developmental or chronic lifetime exposure to organotins may therefore act as a chemical stressor for obesity and related disorders.

scholarly journals Beyond peroxisome proliferator-activated receptor γ signaling: the multi-facets of the antitumor effect of thiazolidinediones

2006 ◽  
Vol 13 (2) ◽  
pp. 401-413 ◽  
Author(s):  
J-R Weng ◽  
C-Y Chen ◽  
J J Pinzone ◽  
M D Ringel ◽  
C-S Chen
Keyword(s):  
Gene Expression ◽  
Anticancer Agents ◽  
Specific Antigen ◽  
Underlying Mechanism ◽  
Peroxisome Proliferator ◽  
Inhibitory Protein ◽  
Antitumor Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Bh3 Domain ◽  
B Cell Leukemia

Certain members of the thiazolidinedione (TZD) family of the peroxisome proliferator-activated receptor γ (PPARγ) agonists, such as troglitazone and ciglitazone, exhibit antitumor activities; however, the underlying mechanism remains inconclusive. Substantial evidence suggests that the antiproliferative effect of these TZD members in cancer cells is independent of PPARγ activation. To discern the role of PPARγ in the antitumor effects of TZDs, we have synthesized PPARγ-inactive TZD analogs which, although devoid of PPARγ activity, retain the ability to induce apoptosis with a potency equal to that of their parental TZDs in cancer cell lines with varying PPARγ expression status. Mechanistic studies from this and other laboratories have further suggested that troglitazone and ciglitazone mediate antiproliferative effects through a complexity of PPARγ-independent mechanisms. Evidence indicates that troglitazone and ciglitazone block BH3 domain-mediated interactions between the anti apoptotic Bcl-2 (B-cell leukemia/lymphoma 2) members Bcl-2/Bcl-xL and proapoptotic Bcl-2 members. Moreover, these TZDs facilitate the degradation of cyclin D1 and caspase-8-related FADD-like IL-l-converting enzyme (FLICE)-inhibitory protein through proteasome-mediated proteolysis, and down-regulate the gene expression of prostate-specific antigen gene expression by inhibiting androgen activation of the androgen response elements in the promoter region. More importantly, dissociation of the effects of TZDs on apoptosis from their original pharmacological activity (i.e. PPARγ activation) provides a molecular basis for the exploitation of these compounds to develop different types of molecularly targeted anticancer agents. These TZD-derived novel therapeutic agents, alone or in combination with other anticancer drugs, have translational relevance in fostering effective strategies for cancer treatment.

scholarly journals The endocrine disruptor mono-(2-ethylhexyl)phthalate promotes adipocyte differentiation and induces obesity in mice

2012 ◽  
Vol 32 (6) ◽  
pp. 619-629 ◽  
Author(s):  
Chanjuan Hao ◽  
Xuejia Cheng ◽  
Hongfei Xia ◽  
Xu Ma
Keyword(s):  
Target Genes ◽  
Adipocyte Differentiation ◽  
Cell Model ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Glucose Levels ◽  
Ethylhexyl Phthalate

The environmental obesogen hypothesis proposes that exposure to endocrine disruptors during developmental ‘window’ contributes to adipogenesis and the development of obesity. MEHP [mono-(2-ethylhexyl) phthalate], a metabolite of the widespread plasticizer DEHP [di-(2-ethylhexyl) phthalate], has been found in exposed organisms and identified as a selective PPARγ (peroxisome-proliferator-activated receptor γ) modulator. However, implication of MEHP on adipose tissue development has been poorly investigated. In the present study, we show the dose-dependent effects of MEHP on adipocyte differentiation and GPDH (glycerol-3-phosphate dehydrogenase) activity in the murine 3T3-L1 cell model. MEHP induced the expression of PPARγ as well as its target genes required for adipogenesis in vitro. Moreover, MEHP perturbed key regulators of adipogenesis and lipogenic pathway in vivo. In utero exposure to a low dose of MEHP significantly increased b.w. (body weight) and fat pad weight in male offspring at PND (postnatal day) 60. In addition, serum cholesterol, TAG (triacylglycerol) and glucose levels were also significantly elevated. These results suggest that perinatal exposure to MEHP may be expected to increase the incidence of obesity in a sex-dependent manner and can act as a potential chemical stressor for obesity and obesity-related disorders.

scholarly journals PTEN Methylation Promotes Inflammation and Activation of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiao-Feng Li ◽  
Sha Wu ◽  
Qi Yan ◽  
Yuan-Yuan Wu ◽  
He Chen ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Articular Cartilage ◽  
Dna Methyltransferase ◽  
Underlying Mechanism ◽  
Cartilage Destruction ◽  
Specific Pcr ◽  
Methylation Inhibitor ◽  
Fibroblast Like Synoviocytes

Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and subsequent destruction of adjacent articular cartilage and bone. In our previous work we showed that phosphatase and tension homolog deleted on chromosome 10 (PTEN) contributes to the activation of fibroblast-like synoviocytes (FLS) in adjuvant-induced arthritis (AIA), but the underlying mechanism is not unknown. In this study, we show that PTEN is downregulated while DNA methyltransferase (DNMT)1 is upregulated in FLS from RA patients and a rat model of AIA. DNA methylation of PTEN was increased by administration of tumor necrosis factor (TNF)-α in FLS of RA patients, as determined by chromatin immunoprecipitation and methylation-specific PCR. Treatment with the methylation inhibitor 5-azacytidine suppressed cytokine and chemokine release and FLS activation in vitro and alleviated paw swelling in vivo. PTEN overexpression reduced inflammation and activation of FLS via protein kinase B (AKT) signaling in RA, and intra-articular injection of PTEN-expressing adenovirus into the knee of AIA rats markedly reduced inflammation and paw swelling. Thus, PTEN methylation promotes the inflammation and activation of FLS in the pathogenesis of RA. These findings provide insight into the molecular basis of articular cartilage destruction in RA, and indicate that therapeutic strategies that prevent PTEN methylation may an effective treatment.

scholarly journals Maternal exercise conveys protection against NAFLD in the offspring via hepatic metabolic programming

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Inga Bae-Gartz ◽  
Philipp Kasper ◽  
Nora Großmann ◽  
Saida Breuer ◽  
Ruth Janoschek ◽  
...  
Keyword(s):  
Early Life ◽  
Body Weight Gain ◽  
Hepatic Metabolism ◽  
Underlying Mechanism ◽  
Peroxisome Proliferator ◽  
Protective Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Alcoholic Fatty Liver ◽  
Hepatic Expression ◽  
Maternal Exercise

Abstract Maternal exercise (ME) during pregnancy has been shown to improve metabolic health in offspring and confers protection against the development of non-alcoholic fatty liver disease (NAFLD). However, its underlying mechanism are still poorly understood, and it remains unclear whether protective effects on hepatic metabolism are already seen in the offspring early life. This study aimed at determining the effects of ME during pregnancy on offspring body composition and development of NAFLD while focusing on proteomic-based analysis of the hepatic energy metabolism during developmental organ programming in early life. Under an obesogenic high-fat diet (HFD), male offspring of exercised C57BL/6J-mouse dams were protected from body weight gain and NAFLD in adulthood (postnatal day (P) 112). This was associated with a significant activation of hepatic AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor alpha (PPARα) and PPAR coactivator-1 alpha (PGC1α) signaling with reduced hepatic lipogenesis and increased hepatic β-oxidation at organ programming peak in early life (P21). Concomitant proteomic analysis revealed a characteristic hepatic expression pattern in offspring as a result of ME with the most prominent impact on Cholesterol 7 alpha-hydroxylase (CYP7A1). Thus, ME may offer protection against offspring HFD-induced NAFLD by shaping hepatic proteomics signature and metabolism in early life. The results highlight the potential of exercise during pregnancy for preventing the early origins of NAFLD.

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