Translocation Of PPARγ Research Articles

Key role of PPAR-γ-mediated suppression of the NFκB signaling pathway in rutin's antidepressant effect

BackgroundDepression is a chronic and recurrent disorder with an unknown etiology. Efficacious antidepressant treatments with minimal side effects are urgently needed. Neuroinflammation may contribute to depression, as anti-inflammatory drugs have been shown to alleviate depressive symptoms in clinical practice. Rutin, a naturally occurring flavonoid derived from plants, is abundant in many antidepressant herbs, including Hemerocallis citrina Baroni. Historical Chinese medical texts, including the renowned Compendium of Materia Medica, document H. citrina Baroni as possessing antidepressant properties. Rutin, one of its primary active constituents, is recognized for its anti-inflammatory effects. Despite this, little is known about its specific target and mechanism. MethodsIn the present study, molecular docking, and surface plasmon resonance imaging (SPRi) analysis were used to identify the special targets of rutin. Meanwhile, the potential antidepressant effects were evaluated in the chronic social defeat stress (CSDS) paradigm, an animal model of depression. Then, Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), Co-immunoprecipitation (Co-IP) as well as antagonists of PPAR-γ were utilized to investigate the mechanism underlying the antidepressant effect of rutin. ResultsBoth molecular docking and SPRi analysis showed high docking scores and interactions between rutin and PPAR-γ. In vivo, rutin promoted the nuclear translocation of PPAR-γ in the hippocampus of mice, inhibited NFκB-mediated inflammatory pathways, and subsequently reduced the expression of pro-inflammatory factors (e.g., iNOS, IL-6), aligning with an antidepressant effect. However, this therapeutic effect was attenuated by GW9662, a specific antagonist of PPAR-γ. ConclusionAs a result of activating PPAR-γ and inhibiting NFκB pathway activation, rutin reduces neuroinflammation and exhibits an antidepressant effect. These findings shed light on the antidepressant mechanism of rutin and could be valuable for the development of new antidepressants.

Canagliflozin alleviates pulmonary hypertension by activating PPARγ and inhibiting its S225 phosphorylation

Pulmonary hypertension (PH) is a progressive fatal disease with no cure. Canagliflozin (CANA), a novel medication for diabetes, has been found to have remarkable cardiovascular benefits. However, few studies have addressed the effect and pharmacological mechanism of CANA in the treatment of PH. Therefore, our study aimed to investigate the effect and pharmacological mechanism of CANA in treating PH. First, CANA suppressed increased pulmonary artery pressure, right ventricular hypertrophy, and vascular remodeling in both mouse and rat PH models. Network pharmacology, transcriptomics, and biological results suggested that CANA could ameliorate PH by suppressing excessive oxidative stress and pulmonary artery smooth muscle cell proliferation partially through the activation of PPARγ. Further studies demonstrated that CANA inhibited phosphorylation of PPARγ at Ser225 (a novel serine phosphorylation site in PPARγ), thereby promoting the nuclear translocation of PPARγ and increasing its ability to resist oxidative stress and proliferation. Taken together, our study not only highlighted the potential pharmacological effect of CANA on PH but also revealed that CANA-induced inhibition of PPARγ Ser225 phosphorylation increases its capacity to counteract oxidative stress and inhibits proliferation. These findings may stimulate further research and encourage future clinical trials exploring the therapeutic potential of CANA in PH treatment.

PPARγ activation by fisetin mitigates vascular smooth muscle cell senescence via the mTORC2-FoxO3a-autophagy signaling pathway

Cellular senescence is caused by diverse stimuli and contributes to cardiovascular diseases. Several studies have indicated that PPARγ acts as a key mediator of lipid metabolism and shown that it has a protective effect on vascular biology. Nevertheless, the mechanism responsible for the anti-aging effects of PPARγ has not been fully elucidated in vascular smooth muscle cell (VSMC). Furthermore, although mTOR complex 2 (mTORC2) is known to be involved in cellular senescence and autophagy, relatively few studies have investigated its effects as compared with mTOR complex 1 (mTORC1). Therefore, we focused on mTORC2 function and investigated the relationship between PPARγ and mTORC2, and the anti-aging mechanism in VSMC. We found PPARγ activation dose-dependently mitigated the hydrogen peroxide (H2O2)-induced senescence. Treatment of fisetin induced the translocation of PPARγ from cytosol to nuclear and inhibited VSMC senescence. Moreover, activated PPARγ increased PTEN transcription, leading to inhibition of the mTORC2 signaling pathway. We determined mTORC2 activation contributed to senescence by suppressing the FoxO3a-autophagy signaling pathway, and dual knockdown of mTORC1 and mTORC2 decreased cellular senescence and increased autophagy activation more than respective single knockdown. Finally, fisetin acted as a PPARγ activator and inhibited VSMC senescence through the mTORC2-FoxO3a-autophagy signaling pathway. These results demonstrate PPARγ is associated with cellular senescence and that fisetin has an anti-aging effect via PPARγ activation and mTORC2 inhibition in VSMC. These results demonstrate that the mTORC2 signaling pathway regulates autophagy and cellular senescence, which suggests mTORC2 should be considered a significant target for preventing cellular senescence and age-related diseases.

Tumor necrosis factor-α reduces adiponectin production by decreasing transcriptional activity of peroxisome proliferator-activated receptor-γ in calf adipocytes

Adiponectin (encoded by ADIPOQ) is an adipokine that orchestrates energy homeostasis by modulating glucose and fatty acid metabolism in peripheral tissues. During the periparturient period, dairy cows often develop adipose tissue inflammation and decreased plasma adiponectin levels. Proinflammatory cytokine tumor necrosis factor-α (TNF-α) plays a pivotal role in regulating the endocrine functions of adipocytes, but whether it affects adiponectin production in calf adipocytes remains obscure. Thus, the present study aimed to determine whether TNF-α could affect adiponectin production in calf adipocytes and to identify the underlying mechanism. Adipocytes isolated from Holstein calves were differentiated and used for (1) BODIPY493/503 staining; (2) treatment with 0.1 ng/mL TNF-α for different times (0, 8, 16, 24, or 48 h); (3) transfection with peroxisome proliferator-activated receptor-γ (PPARG) small interfering RNA for 48 h followed by treatment with or without 0.1 ng/mL TNF-α for 24 h; and (4) overexpression of PPARG for 48 h followed by treatment with or without 0.1 ng/mL TNF-α for 24 h. After differentiation, obvious lipid droplets and secretion of adiponectin were observed in adipocytes. Treatment with TNF-α did not alter mRNA abundance of ADIPOQ but reduced the total and high molecular weight (HMW) adiponectin content in the supernatant of adipocytes. Quantification of mRNA abundance of endoplasmic reticulum (ER)/Golgi resident chaperones involved in adiponectin assembly revealed that ER protein 44 (ERP44), ER oxidoreductase 1α (ERO1A), and disulfide bond-forming oxidoreductase A-like protein (GSTK1) were downregulated in TNF-α-treated adipocytes, while 78-kDa glucose-regulated protein and Golgi-localizing γ-adaptin ear homology domain ARF binding protein-1 were unaltered. Moreover, TNF-α diminished nuclear translocation of PPARγ and downregulated mRNA abundance of PPARG and its downstream target gene fatty acid synthase, suggesting that TNF-α suppressed the transcriptional activity of PPARγ. In the absence of TNF-α, overexpression of PPARG enhanced the total and HMW adiponectin content in supernatant and upregulated the mRNA abundance of ADIPOQ, ERP44, ERO1A, and GSTK1 in adipocytes. However, knockdown of PPARG reduced the total and HMW adiponectin content in supernatant and downregulated the mRNA abundance of ADIPOQ, ERP44, ERO1A, and GSTK1 in adipocytes. In the presence of TNF-α, overexpression of PPARG decreased, while knockdown of PPARG further exacerbated TNF-α-induced reductions in total and HMW adiponectin secretion and gene expression of ERP44, ERO1A, and GSTK1. Overall, TNF-α reduces adiponectin assembly in the calf adipocyte, which may be partly mediated by attenuation of PPARγ transcriptional activity. Thus, locally elevated levels of TNF-α in adipose tissue may be one reason for the decrease in circulating adiponectin in periparturient dairy cows.

αCGRP deficiency aggravates pulmonary fibrosis by activating the PPARγ signaling pathway

In order to explore whether αCGRP (Calca) deficiency aggravates pulmonary fibrosis (PF). Clinical data from patients with PF (n = 52) were retrospectively analyzed. Lung tissue from a bleomycin (BLM)-induced rat model was compared with that of Calca-knockout (KO) and wild type (WT) using immunohistochemistry, RNA-seq, and UPLC-MS/MS metabolomic analyses. The results showed that decreased αCGRP expression and activation of the type 2 immune response were detected in patients with PF. In BLM-induced and Calca-KO rats, αCGRP deficiency potentiated apoptosis of AECs and induced M2 macrophages. RNA-seq identified enrichment of pathways involved in nuclear translocation and immune system disorders in Calca-KO rats compared to WT. Mass spectrometry of lung tissue from Calca-KO rats showed abnormal lipid metabolism, including increased levels of LTB4, PDX, 1-HETE. PPAR pathway signaling was significantly induced in both transcriptomic and metabolomic datasets in Calca-KO rats, and immunofluorescence analysis confirmed that the nuclear translocation of PPARγ in BLM-treated and Calca-KO rats was synchronized with STAT6 localization in the cytoplasmic and nuclear fractions. In conclusion, αCGRP is protective against PF, and αCGRP deficiency promotes M2 polarization of macrophages, probably by activating the PPARγ pathway, which leads to activation of the type 2 immune response and accelerates PF development.

Micro-Current Stimulation Can Modulate the Adipogenesis Process by Regulating the Insulin Signaling Pathway in 3T3-L1 Cells and ob/ob Mice.

Obesity is a disease in which fat is abnormally or excessively accumulated in the body, and many studies have been conducted to overcome it with various techniques. In this study, we evaluated whether micro-current stimulation (MCS) can be applied to prevent obesity by regulating the adipogenesis through 3T3-L1 cells and ob/ob mice. To specify the intensity of MCS, Oil Red O staining was conducted with various intensities of MCS. Based on these, subsequent experiments used 200 and 400 μA for the intensity of MCS. The expressions of insulin signaling pathway-related proteins, including phosphorylation of IGF-1 and IR, were decreased in all MCS groups, and in turn, downstream signals such as Akt and ERK were decreased. In addition, MCS reduced the nucleus translocation of PPAR-γ and decreased the protein expression of C/EBP-α. In the ob/ob mouse model, MCS reduced body weight gain and abdominal adipose tissue volume. In particular, the concentration of triglycerides in serum was also decreased. Taken together, our findings showed that MCS inhibited lipid accumulation by regulating insulin signaling in 3T3-L1, and it was effective at reducing body weight and adipose tissue volume in ob/ob mice. These suggest that MCS may be a useful treatment approach for obesity.

Candesartan Does Not Activate PPARγ and Its Target Genes in Early Gestation Trophoblasts.

Angiotensin II receptor 1 blockers are commonly used to treat hypertension in women of childbearing age. While the fetotoxic effects of these drugs in the second and third trimesters of pregnancy are well documented, their possible impacts on placenta development in early gestation are unknown. Candesartan, a member of this group, also acts as a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, a key regulator shown to be important for placental development. We have previously shown that trophoblasts do not express the candesartan target–receptor angiotensin II type 1 receptor AGTR1. This study investigated the possible role of candesartan on trophoblastic PPARγ and its hallmark target genes in early gestation. Candesartan did not affect the PPARγ protein expression or nuclear translocation of PPARγ. To mimic extravillous trophoblasts (EVTs) and cytotrophoblast/syncytiotrophoblast (CTB/SCT) responses to candesartan, we used trophoblast cell models BeWo (for CTB/SCT) and SGHPL-4 (EVT) cells as well as placental explants. In vitro, the RT-qPCR analysis showed no effect of candesartan treatment on PPARγ target genes in BeWo or SGHPL-4 cells. Treatment with positive control rosiglitazone, another PPARγ agonist, led to decreased expressions of LEP and PPARG1 in BeWo cells and an increased expression of PPARG1 in SGHPL-4 cells. Our previous data showed early gestation–placental AGTR1 expression in fetal myofibroblasts only. In a CAM assay, AGTR1 was stimulated with angiotensin II and showed increased on-plant vessel outgrowth. These results suggest candesartan does not negatively affect PPARγ or its target genes in human trophoblasts. More likely, candesartan from maternal serum may first act on fetal-placental AGTR1 and influence angiogenesis in the placenta, warranting further research.

Wutou decoction attenuates the synovial inflammation of collagen-induced arthritis rats via regulating macrophage M1/M2 type polarization

Ethnopharmacological relevanceThousands of years of clinical practice in the treatment of joint-related diseases support the efficacy and safety of Wutou decoction (WTD). Nevertheless, the lack of pharmacological evidence and unclear mechanisms make it difficult for WTD to become a recognized complementary therapy for the treatment of rheumatoid arthritis (RA). Aim of the studyThis study aimed to investigate the effect of WTD against synovial inflammation in RA and whether this effect depends on the regulation of macrophage polarization. Materials and methodsSprague-Dawley rats were used to establish the collagen-induced arthritis (CIA) model. WTD with low and high doses was administered for 45 days. RAW264.7 cells were stimulated by lipopolysaccharide (LPS) or interleukin (IL)-4 to polarize M1 and M2 macrophages, which were pre-treated with WTD extract for 4 h. The anti-arthritic and anti-inflammatory effects of WTD were studied using arthritis score, histopathological staining, immunostaining, and enzyme-linked immunosorbent assay (ELISA). The polarization state of RAW264.7 cells and related pro/anti-inflammatory cytokines was detected by ELISA, reverse transcription quantitative polymerase chain reaction and western blotting. Western blotting and immunofluorescence were used to investigate the effect of WTD on nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and peroxisome proliferator-activated receptors γ (PPARγ) activation both in vivo and in vitro. ResultsWTD significantly reduced the arthritis score and the pathological damage of the knee joint and decreased the expression of tumor necrosis factor alpha (TNF-α), IL-6 in serum, TNF-α, IL-1β, monocyte chemoattractant protein-1 (MCP-1), and matrix metalloproteinase-3 (MMP3) in the knee synovium. WTD inhibited M1 type polarization and promoted M2 type polarization, both in vitro and in vivo, and reduced the expression of pro-inflammatory cytokines while increasing the expression of anti-inflammatory cytokines. Experiments showed that WTD inhibited the phosphorylation of NF-κB and downstream p38 in the synovium of CIA rats and LPS-induced M1 type polarized RAW264.7 cells. In addition, PPARγ expression in the synovium of CIA rats was mainly located in the cytoplasm, and WTD treatment increased the nuclear translocation of PPARγ, which was further verified in RAW264.7 cells. ConclusionsNF-κB and PPARγ regulating M1 and M2 macrophage polarization and subsequent secretion of pro-inflammatory and anti-inflammatory cytokines are the underlying mechanisms of WTD that ameliorate RA synovial inflammation.

Dysregulation of the endomembrane homeostasis triggers vascular smooth muscle cell phenotype switching

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft Background Cardiovascular diseases are a leading cause of mortality globally, with cardiovascular calcification as a prominent predictor and contributor. Notably, microcalcifications might cause atherosclerotic plaque rupture, leading to myocardial infarction. Calcified plaque remodeling accompanies phenotypic modulation of vascular smooth muscle cells (SMCs). Previously, we showed that extracellular vesicles (EVs) released from calcifying SMCs are pivotal for microcalcification formation. EVs originate from the endolysosomal system. The lipid kinase FYVE-type zinc finger containing phosphoinositide kinase (PIKfyve) plays a role in the endolysosomal maturation. Here, we investigated how modulation of the endolysosomal system intersects with SMC phenotype regulation. Methods and Results In calcified arteries and SMCs, we observed increased PIKfyve expression. Inhibition of PIKfyve with the small molecule Apilimod inhibited osteogenic differentiation of SMCs in an in vitro calcification model. Apilimod reduced tissue non-specific alkaline phosphatase (TNAP) – an early marker of SMC calcification on mRNA (-79%, p<0.01), protein (-96%, p<0.01) and activity (-92%, p<0.01) levels. Additionally, matrix mineralization and collagen network formation are inhibited. SMC-secreted EVs exhibited a lower mineral content and reduced aggregation potential assessed by osteosense-based flow cytometry and turbidity assays. Transcriptome analyses revealed that the anti-calcifying effect is accompanied by a decreased expression of contractile SMC genes. Validation by RT-PCR supported that SMC-specific markers (ACTA2, SM22) and the key SMC transcription factor MYOCD were downregulated, while the expression of macrophage-like SMC markers (LGALS3, CD68) was induced. On the other hand, Apilimod increased the expression of adipogenic transcription factors (CEBPA, PPARG) and genes of the cholesterol and fatty acid metabolism pathways (SREBF2, HMGCR, FABP3, CD36) and induced the nuclear translocation of PPARγ, the main regulator of adipogenic differentiation. Fluorescence-based assays revealed increased fatty acid and disrupted low-density lipoprotein (LDL) uptake in Apilimod-treated SMCs. In Ldlr-deficient mice fed a high-fat, high-cholesterol diet for 15 weeks and treated with Apilimod for 5 weeks, we found differentially distributed plaque lipid depositions detected by Oil Red O staining. Conclusion Disrupting the endolysosomal maturation by PIKfyve inhibition ameliorates SMC calcification and induces a phenotypic adipogenic-like, pro-inflammatory adaption. Our data elucidates the importance of SMC phenotype monitoring during therapeutic interference. The exact lineage characteristics of these SMCs remain to be further investigated.

Pentoxifylline alleviates ischemic white matter injury through up-regulating Mertk-mediated myelin clearance

BackgroundVascular dementia (VAD) is the second most common type of dementia lacking effective treatments. Pentoxifylline (PTX), a nonselective phosphodiesterase inhibitor, displays protective effects in multiple cerebral diseases. In this study, we aimed to investigate the therapeutic effects and potential mechanisms of PTX in VAD.MethodsBilateral common carotid artery stenosis (BCAS) mouse model was established to mimic VAD. Mouse behavior was tested by open field test, novel object recognition test, Y-maze and Morris water maze (MWM) tests. Histological staining, magnetic resonance imaging (MRI) and electron microscopy were used to define white matter integrity. The impact of PTX on microglia phagocytosis, peroxisome proliferator-activated receptors-γ (PPAR-γ) activation and Mer receptor tyrosine kinase (Mertk) expression was assessed by immunofluorescence, western blotting and flow cytometry with the application of microglia-specific Mertk knockout mice, Mertk inhibitor and PPAR-γ inhibitor.ResultsHere, we found that PTX treatment alleviated cognitive impairment in novel object recognition test, Y-maze and Morris water maze tests. Furthermore, PTX alleviated white matter injury in corpus callosum (CC) and internal capsule (IC) areas as shown by histological staining and MRI analysis. PTX-treatment group presented thicker myelin sheath than vehicle group by electron microscopy. Mechanistically, PTX facilitated microglial phagocytosis of myelin debris by up-regulating the expression of Mertk in BCAS model and primary cultured microglia. Importantly, microglia-specific Mertk knockout blocked the therapeutic effects of PTX in BCAS model. Moreover, Mertk expression was regulated by the nuclear translocation of PPAR-γ. Through modulating PPAR-γ, PTX enhanced Mertk expression.ConclusionsCollectively, our results demonstrated that PTX showed therapeutic potentials in VAD and alleviated ischemic white matter injury via modulating Mertk-mediated myelin clearance in microglia.

The peroxisome proliferator-activated receptor agonist rosiglitazone specifically represses tumour metastatic potential in chromatin inaccessibility-mediated FABP4-deficient gastric cancer.

Background: Efforts to prevent recurrence in gastric cancer (GC) patients are limited by current incomplete understanding of the pathological mechanisms. The present study aimed to identify novel tumour metastasis-associated genes and investigate potential value of these genes in clinical diagnosis and therapy.Methods: RNA sequencing was performed to identify differentially expressed genes related to GC metastasis. The expression and prognostic significance of fatty acid binding protein 4 (FABP4) were evaluated in two independent cohorts of GC patients. Chromatin immunoprecipitation sequencing, diverse mouse models and assays for transposase-accessible chromatin with high-throughput sequencing were used to investigate the roles and mechanisms of action of FABP4.Results: The results of the present multicentre study confirmed an association between a decrease in the expression of FABP4 and poor outcomes in GC patients. FABP4 inhibited GC metastasis but did not influence tumour growth in vitro and in vivo. Mechanistically, FABP4 binding with peroxisome proliferator-activated receptor γ (PPAR-γ) facilitated the translocation of PPAR-γ to the nucleus. FABP4 depletion suppressed PPAR-γ-mediated transcription of cell adhesion molecule 3 (CADM3), which preferentially governed GC metastasis. Notably, the PPAR-γ agonist rosiglitazone reversed the metastatic properties of FABP4-deficient GC cells in vitro and demonstrated viable therapeutic potential in multiple mouse models. For GC patients with diabetes, low FABP4 portends better prognosis than high FABP4 after receipt of rosiglitazone treatment. Additionally, chromatin inaccessibility induced by HDAC1 reduced FABP4 expression at the epigenetic level.Conclusions: Our findings suggest that chromatin inaccessibility orchestrates a reduction in FABP4 expression, which inhibits CADM3 transcription via PPAR-γ, thereby resulting in GC metastasis. The antidiabetic drug rosiglitazone restores PPAR-γ/CADM3 activation in FABP4-deficient GC and thus has promising therapeutic potential.

Ablation of KDM2A Inhibits Preadipocyte Proliferation and Promotes Adipogenic Differentiation.

Epigenetic signals and chromatin-modifying proteins play critical roles in adipogenesis, which determines the risk of obesity and which has recently attracted increasing interest. Histone demethylase 2A (KDM2A) is an important component of histone demethylase; however, its direct effect on fat deposition remains unclear. Here, a KDM2A loss of function was performed using two unbiased methods, small interfering RNA (siRNA) and Cre-Loxp recombinase systems, to reveal its function in adipogenesis. The results show that the knockdown of KDM2A by siRNAs inhibited the proliferation capacity of 3T3-L1 preadipocytes. Furthermore, the promotion of preadipocyte differentiation was observed in siRNA-treated cells, manifested by the increasing content of lipid droplets and the expression level of adipogenic-related genes. Consistently, the genetic deletion of KDM2A by Adipoq-Cre in primary adipocytes exhibited similar phenotypes to those of 3T3-L1 preadipocytes. Interestingly, the knockdown of KDM2A upregulates the expression level of Transportin 1(TNPO1), which in turn may induce the nuclear translocation of PPARγ and the accumulation of lipid droplets. In conclusion, the ablation of KDM2A inhibits preadipocyte proliferation and promotes its adipogenic differentiation. This work provides direct evidence of the exact role of KDM2A in fat deposition and provides theoretical support for obesity therapy that targets KDM2A.

Lutein Inhibits IL-6 Expression via PPARγ-Mediated SOCS3 Expression in Cerulein-Stimulated Pancreatic Acinar Cells

Abstract Objectives Cerulein pancreatitis is the best model of human edematous pancreatitis. Our previous studies showed that cerulein induced interleukin-6 (IL-6) expression through janus kinase (JAK)2/signal transducer and activator of transcription (STAT)3 signaling pathway. SOCS3 functions by inhibiting the catalytic activity of JAKs that initiate signaling within the cells. Peroxisome proliferator activated receptor-gamma (PPAR-γ) ligands, 15d-PGJ2 and troglitazone, have been known to induce suppressor of cytokine signaling (SOCS) 3 expression and inhibited JAK2/STAT3 activation in pancreatic acinar cells. Lutein is a carotenoid with reported anti-inflammatory properties. The present study was undertaken to investigate the inhibitory effect and mechanism of lutein on cerulein-induced IL-6 expression by determining expression and activation of PPAR-γ and SOCS3 in pancreatic acinar cells. Methods Rat Pancreatic acinar cells (AR42J cell line) were used. The cells were treated with lutein in the presence or absence of the PPARγ antagonist GW9662, and then stimulated with cerulein. Expression of IL-6 was assessed by real-time PCR analysis. Western blot analysis was performed to determine levels of phosphorylated JAK2/STAT3 and SOCS 3, and nuclear translocation of PPAR. Results Lutein increased expression and nuclear translocation of PPARγ, and expression of SOCS 3 in AR42J cells. Cerulein-induced IL-6 expression, and phosphorylation of JAK2 and STAT3 were inhibited by lutein. GW9662 inhibited lutein-induced expression of SOCS 3. In addition, GW9662 suppressed inhibitory effects of lutein on cerulein-induced IL-6 expression and JAK2/STAT3 activation in AR42J cells. Conclusions Lutein induces PPARγ activation and SOCS 3 expression, which inhibits JAK2/STAT3 activation and IL-6 expression in cerulein-stimulated pancreatic acinar cells. Funding Sources This study was supported by Brain Korea 21 FOUR Project, Yonsei University, Seoul, Republic of Korea.

Effect of rosiglitazone on developmental competence of mouse embryos treated with lipopolysaccharide

Lipopolysaccharide (LPS) significantly reduces pre- and post-implantation developmental competence of embryos. One of the reason of this effect could be a consequence of TLR4-mediated inflammation. In this study, we assessed the anti-inflammatory effect of peroxisome proliferator activated receptor γ (PPAR γ) agonist, rosiglitazone (RGZ), in LPS-treated mouse embryos. Initially, the optimal doses of LPS, RGZ and GW9662 (a potent and selective PPARγ antagonist) were determined by treating the mouse zygotes up to blastocyst stage and assessment of compaction and blastocyst rates. Quantitative PCR was used to assess the mRNA expression of inflammatory cytokines. Immunostaining was used to study the translocation of PPARγ in blastocysts. Finally, the blastocysts were transferred to surrogate mouse to determine the post-implantation developmental competence. 0.0625 mg/mL of LPS significantly reduced the developmental competency by around 50% compared to control group. 10 μM of RGZ significantly ameliorated the toxic effect of LPS, which was also significantly reversed by 1.25 μM GW9662. Through immunostaining, it was shown that LPS could prevent the translocation of PPARγ to nucleus; and translocation was facilitated by RGZ and this effect was reversed by GW9662. A similar effect was also observed for the mRNA expression of inflammatory cytokines (Il-1β and Il-6). LPS significantly increased the expression of these cytokines, while RGZ significantly reduced their expression, which was also significantly reversed by GW9662. It was also shown that embryos exposed to LPS had significantly reduced post implantation developmental competence which was considerably improved by treatment with RGZ. In conclusion, these data may have clinical implications for ameliorating the adverse effects of LPS in dairy farming and infertility treatment.

Redox-dependent PPARγ/Tnpo1 complex formation enhances PPARγ nuclear localization and signaling

The nuclear receptor peroxisome proliferator-activated receptor (PPAR)γ has been implicated in the pathogenesis of various human diseases including fatty liver. Although nuclear translocation of PPARγ plays an important role in PPARγ signaling, details of the translocation mechanisms have not been elucidated. Here we demonstrate that PPARγ2 translocates to the nucleus and activates signal transduction through H2O2-dependent formation of a PPARγ2 and transportin (Tnpo)1 complex via redox-sensitive disulfide bonds between cysteine (Cys)176 and Cys180 of the former and Cys512 of the latter. Using hepatocyte cultures and mouse models, we show that cytosolic H2O2/Tnpo1-dependent nuclear translocation enhances the amount of DNA-bound PPARγ and downstream signaling, leading to triglyceride accumulation in hepatocytes and liver. These findings expand our understanding of the mechanism underlying the nuclear translocation of PPARγ, and suggest that the PPARγ and Tnpo1 complex and surrounding redox environment are potential therapeutic targets in the treatment of PPARγ-related diseases.

Walnut polyphenol extracts inhibit Helicobacter pylori-induced STAT3Tyr705 phosphorylation through activation of PPAR-γ and SOCS1 induction.

The health beneficial effects of walnut plentiful of n-3 polyunsaturated fatty acid had been attributed to its anti-inflammatory and anti-oxidative properties against various clinical diseases. Since we have published Fat-1 transgenic mice overexpressing 3-desaturase significantly mitigated Helicobacter pylori (H. pylori)-associated gastric pathologies including rejuvenation of chronic atrophic gastritis and prevention of gastric cancer, in this study, we have explored the underlying molecular mechanisms of walnut against H. pylori infection. Fresh walnut polyphenol extracts (WPE) were found to suppress the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) induced by H. pylori infection in RGM-1 gastric mucosal cells. Notably, H. pylori infection significantly decreased suppressor of cytokine signaling 1 (SOCS1), but WPE induced expression of SOCS1, by which the suppressive effect of walnut extracts on STAT3Tyr705 phosphorylation was not seen in SOCS1 KO cells. WPE induced significantly increased nuclear translocation nuclear translocation of PPAR-γ in RGM1 cells, by which PPAR-γ KO inhibited transcription of SOCS1 and suppressive effect of WPE on p-STAT3Tyr705 was not seen. WPE inhibited the expression of c-Myc and IL-6/IL-6R signaling, which was attenuated in the RGM1 cells harboring SOCS1 specific siRNA. Conclusively, WPE inhibits H. pylori-induced STAT3 phosphorylation in a PPAR-γ and SOCS1-dependent manner.

Synthesis, Docking Studies and Biological Evaluation of Triazole‐Thiazolidinedione/Rhodanine Hybrids Targeting Cyclooxygenase‐2, 5‐Lipoxygenase and Peroxisome proliferator‐activated receptor

Inflammation is associated with different clinical conditions including rheumatoid disorders and multiple sclerosis. Recently, inflammation has been linked to metabolic diseases, such as diabetes. In addition to their antidiabetic effect, thiazolidinediones (TZDs), through PPARγ transactivation, are also known to negatively control transcriptional pathways that are critical for the synthesis of pro‐inflammatory molecules. Moreover, selective COX‐2 inhibitors serve as effective anti‐inflammatory agents with minimal GIT side effects; however, only blocking COX‐2 shunts the inflammatory pathways towards more activity of LOX, and hence blocking both COX‐2 and LOX would provide safer and more effective anti‐inflammatory activity. In our search for multi‐targeting anti‐inflammatory leads, we adopted a hybrid pharmacophore approach to design and synthesize some novel triazolyl‐thiazolidinedione/rhodanine hybrids as potential simultaneous COX‐2/LOX inhibitors and PPARγ agonists. Ten of these compounds demonstrated significant in vitro COX‐2 and 15‐LOX inhibitory activities, four of which exhibited high in vitro tissue glucose uptake. These drugs revealed comparable nuclear PPARγ translocation to that of pioglitazone and luciferase activity. PMA‐induced macrophage differentiation assay conducted on THP‐1 cells demonstrated similar or exceeding potency than diclofenac. This translated to in‐vivo formalin‐induced rat paw edema bioassay where the selected drugs showed an anti‐inflammatory activity. The pharmacological data were coherent with the in silico results. Accordingly, this series of compounds may represent promising leads to pursue as potential simultaneous COX‐2/LOX inhibitors and PPARγ agonists for the management of diabetes and other inflammatory disorders.Support or Funding InformationPartially supported by AUB MPP fund #320148This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Senescence Alters PPARγ (Peroxisome Proliferator-Activated Receptor Gamma)-Dependent Fatty Acid Handling in Human Adipose Tissue Microvascular Endothelial Cells and Favors Inflammation.

Adipose tissue (AT) dysfunction associated with obesity or aging is a major cause for lipid redistribution and the progression of cardiometabolic disorders. Our goal is to decipher the contribution of human AT microvascular endothelial cells (ECs) in the maintenance of fatty acid (FA) fluxes and the impact of senescence on their function. We used freshly isolated primary microvascular ECs from human AT. Our data identified the endothelial FA handling machinery including FATPs (FA transport proteins) FATP1, FATP3, FATP4, and CD36 as well as FABP4 (FA binding protein 4). We showed that PPARγ (peroxisome proliferator-activated receptor gamma) regulates the expression of FATP1, CD36, and FABP4 and is a major regulator of FA uptake in human AT EC (hATEC). We provided evidence that endothelial PPARγ activity is modulated by senescence. Indeed, the positive regulation of FA transport by PPARγ agonist was abolished, whereas the emergence of an inflammatory response was favored in senescent hATEC. This was associated with the retention of nuclear FOXO1 (forkhead box protein O1), whereas nuclear PPARγ translocation was impaired. These data support the notion that PPARγ is a key regulator of primary hATEC function including FA handling and inflammatory response. However, the outcome of PPARγ activation is modulated by senescence, a phenomenon that may impact the ability of hATEC to properly respond to and handle lipid fluxes. Finally, our work highlights the role of hATEC in the regulation of FA fluxes and reveals that dysfunction of these cells with accelerated aging is likely to participate to AT dysfunction and the redistribution of lipids.

Hydroxysafflor-Yellow A Induces Human Gastric Carcinoma BGC-823 Cell Apoptosis by Activating Peroxisome Proliferator-Activated Receptor Gamma (PPARγ).

BackgroundAnti-tumor properties of hydroxysafflor-yellow A (HSYA) have been recently revealed, as a series of apoptotic factors were confirmed to be regulated by HSYA and associated with peroxisome proliferator-activated receptor Gamma (PPARγ). In this study, we investigated the cell apoptosis mechanism of HSYA via activated PPARγ signal in human gastric carcinoma cells.Material/MethodsBGC-823 cells were cultured and divided into 5 independent groups: Tumor, HSYA, HSYA+PPARγ inhibitor (GW9662), and PPARγ agonist (RGZ), RGZ+GW9662. Cell proliferative activity was measured by MTT. Apoptosis and cell cycle were detected by flow cytometry. The nuclear translocation of PPARγ was detected by immunofluorescence staining chemistry, and mRNA levels of PPARγ and caspase-3 were measured by real-time qPCR.ResultsCompared to the RGZ group, the HSYA group (100 μM) showed a similar inhibitory effect on the proliferation process of BGC-823 cells, inducing their apoptosis. As a result, the transition of BGC-823 cells from G0/G1 phase to S phase was blocked. HSYA was also found to promote the nuclear translocation of PPARγ, leading to increased expression of PPARγ and caspase-3. The regulatory effect of HSYA on BGC-823 cells could be further inhibited by PPARγ inhibitor in group GW9662.ConclusionsWe report the inhibitory effect of HSYA on the proliferation of BGC-823 cells, which results in activating PPARγ-dependent cell cycle blocking and cell apoptosis, suggesting that PPARγ is a specific type of HSYA that can induce apoptosis of BGC-823 cells.

The \u03b1-melanocyte stimulating hormone/peroxisome proliferator activated receptor-\u03b3 pathway down-regulates proliferation in melanoma cell lines

BackgroundThe α-Melanocyte Stimulating Hormone (αMSH)/Melanocortin-1 receptor (MC1R) interaction promotes melanogenesis through the cAMP/PKA pathway. The direct induction of this pathway by Forskolin (FSK) is also known to enhance melanocyte proliferation. αMSH acts as a mitogenic agent in melanocytes and its effect on proliferation of melanoma cells is less known. We previously identified the αMSH/Peroxisome Proliferator Activated Receptor (PPARγ) pathway as a new pathway on the B16-F10 mouse melanoma cell line. αMSH induced the translocation of PPARγ into the nucleus as an active transcription factor. This effect was independent of the cAMP/PKA pathway and was mediated by the activation of the PI(4,5)P2/PLC pathway, a pathway which we have described to be triggered by the αMSH-dependent MC1R stimulation. Moreover, in the same study, preliminary experiments showed that mouse melanoma cells responded to αMSH by reducing proliferation and that PPARγ was involved in this effect. Due to its key role in the control of cell proliferation, PPARγ agonists are used in therapeutic models for different forms of cancer, including melanoma. The purpose of this study was: (a) to confirm the different proliferative behavior in response to αMSH in healthy and in melanoma condition; (b) to verify whether the cAMP/PKA pathway and the PLC/PPARγ pathway could exert an antagonistic function in the control of proliferation; (c) to deepen the knowledge of the molecular basis responsible for the down-proliferative response of melanoma cells after exposure to αMSH.MethodsWe employed B16-F10 cell line, a human melanoma cell line (Mel 13) and two primary cultures of human melanocytes (NHM 1 and NHM 2, respectively), all expressing a wild type MC1R and responding to the αMSH in terms of pigmentation. We evaluated cell proliferation through: a) cell counting, b) cell cycle analysis c) protein expression of proliferation modulators (p27, p21, cyclin D1 and cyclin E).ResultsThe αMSH acted as a mitogenic agent in primary cultures of human melanocytes, whereas it determined a slow down of proliferation in melanoma cell lines. FSK, as an inducer of the cAMP/PKA pathway, reproduced the αMSH mediated effect on proliferation in NHMs but it did not mimic the αMSH effect on proliferation in B16-F10 and Mel 13 melanoma cell lines. Meanwhile, 3 M3-FBS (3 M3), as an inducer of PI(4,5)P2/PLC pathway, reproduced the αMSH proliferative effect. Further experiments, treating melanoma cell lines with αMSH in the presence/absence of GW9662, as an inhibitor of PPARγ, confirmed the key role of this transcription factor in decreasing cell proliferation in response to the hormone exposure.ConclusionsIn both melanoma cell lines, αMSH determined the reduction of proliferation through the PI(4,5)P2/PLC pathway, employing PPARγ as an effector element. These evidence could offer perspectives for new therapeutic approaches for melanoma.