Anti-inflammatory properties of a dual PPARgamma/alpha agonist muraglitazar in in vitro and in vivo models

PPAR-γ Agonist GW1929 Targeted to Macrophages with Dendrimer-Graphene Nanostars Reduces Liver Fibrosis and Inflammation

Macrophages play essential roles during the progression of chronic liver disease. They actively participate in the response to liver damage and in the balance between fibrogenesis and regression. The activation of the PPARγ nuclear receptor in macrophages has traditionally been associated with an anti-inflammatory phenotype. However, there are no PPARγ agonists with high selectivity for macrophages, and the use of full agonists is generally discouraged due to severe side effects. We designed dendrimer-graphene nanostars linked to a low dose of the GW1929 PPARγ agonist (DGNS-GW) for the selective activation of PPARγ in macrophages in fibrotic livers. DGNS-GW preferentially accumulated in inflammatory macrophages in vitro and attenuated macrophage pro-inflammatory phenotype. The treatment with DGNS-GW in fibrotic mice efficiently activated liver PPARγ signaling and promoted a macrophage switch from pro-inflammatory M1 to anti-inflammatory M2 phenotype. The reduction of hepatic inflammation was associated with a significant reduction in hepatic fibrosis but did not alter liver function or hepatic stellate cell activation. The therapeutic antifibrotic utility of DGNS-GW was attributed to an increased expression of hepatic metalloproteinases that allowed extracellular matrix remodeling. In conclusion, the selective activation of PPARγ in hepatic macrophages with DGNS-GW significantly reduced hepatic inflammation and stimulated extracellular matrix remodeling in experimental liver fibrosis.

Novel derivatives of eugenol as potent anti-inflammatory agents via PPARγ agonism: rational design, synthesis, analysis, PPARγ protein binding assay and computational studies

Eugenol is a natural product abundantly found in clove buds known for its pharmacological activities such as anti-inflammatory, antidiabetic, antioxidant, and anticancer activities. It is well known from the literature that peroxisome proliferator-activated receptors (PPARγ) have been reported to regulate inflammatory responses. In this backdrop, we rationally designed semi-synthetic derivatives of eugenol with the aid of computational studies, and synthesized, purified, and analyzed four eugenol derivatives as PPARγ agonists. Compounds were screened for PPARγ protein binding by time-resolved fluorescence (TR-FRET) assay. The biochemical assay results were favorable for 1C which exhibited significant binding affinity with an IC50 value of 10.65 μM as compared to the standard pioglitazone with an IC50 value of 1.052 μM. In addition to the protein binding studies, as a functional assay, the synthesized eugenol derivatives were screened for in vitro anti-inflammatory activity at concentrations ranging from 6.25 μM to 400 μM. Among the four compounds tested 1C shows reasonably good anti-inflammatory activity with an IC50 value of 133.8 μM compared to a standard diclofenac sodium IC50 value of 54.32 μM. Structure-activity relationships are derived based on computational studies. Additionally, molecular dynamics simulations were performed to examine the stability of the protein-ligand complex, the dynamic behavior, and the binding affinity of newly synthesized molecules. Altogether, we identified novel eugenol derivatives as potential anti-inflammatory agents via PPARγ agonism.

A Retinoid X Receptor Agonist Directed to the Large Intestine Ameliorates T-Cell-Mediated Colitis in Mice

Retinoid X receptor (RXR) is a nuclear receptor that heterodimerizes with several nuclear receptors, integrating ligand-mediated signals across the heterodimers. Synthetic RXR agonists have been developed to cure certain inflammatory diseases, including inflammatory bowel diseases (IBDs). However, pre-existing RXR agonists, which are lipophilic and readily absorbed in the upper intestine, cause considerable adverse effects such as hepatomegaly, hyperlipidemia, and hypothyroidism. To minimize these adverse effects, we have developed an RXR agonist, NEt-3IB, which has lipophilic and thus poorly absorptive properties. In this study, we evaluated the effects of NEt-3IB in an experimental murine colitis model induced through the adoptive transfer of CD45RB^highCD4⁺ T cells. Pharmacokinetic studies demonstrated that the major portion of NEt-3IB was successfully delivered to the large intestine after oral administration. Notably, NEt-3IB treatment suppressed the development of T cell-mediated chronic colitis, as indicated by improvement of wasting symptoms, inflammatory infiltration, and mucosal hyperplasia. The protective effect of NEt-3IB was mediated by the suppression of IFN-γ-producing Th1 cell expansion in the colon. In conclusion, NEt-3IB, a large intestine-directed RXR agonist, is a promising drug candidate for IBDs.

PPAR-δ agonist affects adipo-chondrogenic differentiation of human mesenchymal stem cells through the expression of PPAR-γ

Introduction

Peroxisome proliferator–activated receptor (PPAR) subfamily play an important role in chondrogenesis. Previous study has reported that mixture of GW0742 (PPAR-δ agonist), hyaluronic acid (HA) and mesenchymal stem cells (MSCs) enhance chondrogenesis. The purpose of this study is to compare with efficacies of commercially available HA and demonstrate correlation of PPAR-γ and PPAR-δ.

Methods

In this experimental study, MSCs were cultured with chondrogenic media and clinical HA gels (Euflexxa®, Synvisc®, Orthovisc® and Supartz®) using micormass culture method. Expression of type Ⅰ, Ⅱ collagen and matrix metalloprotease-13 (MMP-13) was measured by immunoblotting. MSCs were cultured with chondrogenic media and/or HA and/or GW0742 and/or rosiglitazone (PPAR-γ agonist) and/or human osteoarthritis synovial fluid. Immunoblotting was used to measure expression of type Ⅱ collagen and PPAR-γ. To identify the effective dose for chondrogenesis and adipogenesis, either 0.1, 1, 5 or 10 μM of rosiglitazone was added to MSCs in chondrogenic media or adipogenic media.

Results

Clinical HA gels inhibited expression of type Ⅰ collagen and enhanced the expression of MMP-13. Type Ⅱ collagen expression was significantly elevated in all treatment groups except Supartz®. GW0742 decreased the expression of PPAR-γ with/without inflammation condition. Rosiglitazone enhanced adipogenesis in a dose-dependent manner and enhanced the expression of type Ⅱ collagen under inflammation condition. Otherwise, the expression of type Ⅱ collagen and formation of chondrocyte spheroids showed a dose-dependent manner with a peak at 1 μM of rosiglitazone.

Conclusions

PPAR-γ has a considerable anti-inflammatory effect and a strong pro-adipogenic effect, which inhibits the chondrogenic effect. PPAR-γ is related with PPAR-δ and shows a chondrogenic effect at lower concentrations. And clinical HA gels shows various efficacy of chondrogenesis. This study suggested that PPAR-γ and PPAR-δ are key regulatory factors of chondrogenesis.

Exercise rescues the immune response fine-tuned impaired by peroxisome proliferator-activated receptors γ deletion in macrophages

BACKGROUND

Exercise is a powerful tool for prevention and treatment of many conditions related to the cardiovascular system and also chronic low-grade inflammation. Peroxisome proliferator-activated receptors γ (PPARγ) exerts an import role on the regulation of metabolic profile and subsequent inflammatory response, especially in macrophages.

PURPOSE

To investigate the effects of 8-week moderate-exercise training on metabolic and inflammatory parameters in mice with PPARγ deficiency in myeloid cells.

METHODS

Twelve-week old mice bearing PPARγ deletion exclusively in myeloid cells (PPARγlox/lox Lys Cre ^-/+ , knockout [KO]) and littermate controls (PPARγlox/lox Lys Cre ^-/- , wild type [WT]) were submitted to 8-week exercise training (treadmill running at moderate intensity, 5 days/week). Animals were evaluated for food intake, glucose homeostasis, serum metabolites, adipose tissue and peritoneal macrophage inflammation, and basal and stimulated cytokine secretion.

RESULTS

Exercise protocol did not improve glucose metabolism or adiponectin concentrations in serum of KO mice. Moreover, the absence of PPARγ in macrophages exacerbated the proinflammatory profile in sedentary mice. Peritoneal cultured cells had higher tumor necrosis factor-α (TNF-α) secretion in nonstimulated and lipopolysaccharide (LPS)-stimulated conditions and higher Toll-4 receptor (TLR4) gene expression under LPS stimulus. Trained mice showed reduced TNF-α content in adipose tissue independently of the genotype. M2 polarization ability was impaired in KO peritoneal macrophages after exercise training, while adipose tissue-associated macrophages did not present any effect by PPARγ ablation.

CONCLUSION

Overall, PPARγ seems necessary to maintain macrophages appropriate response to inflammatory stimulus and macrophage polarization, affecting also whole body lipid metabolism and adiponectin profile. Exercise training showed as an efficient mechanism to restore the immune response impaired by PPARγ deletion in macrophages.

Activation of PPARγ by Curcumin protects mice from ischemia/reperfusion injury induced by orthotopic liver transplantation via modulating polarization of Kupffer cells

Curcumin shows protective effects on various diseases due to its anti-inflammatory and anti-oxidative functions; however, its effect on organ transplantation has not been fully elucidated. To understand its role in liver ischemia/reperfusion (I/R) injury, we studied its impact on orthotopic liver transplantation (OLT) and Kupffer cells (KCs) polarization and its underlying mechanisms. We first investigated the reactive oxygen species (ROS) accumulation and cytokines profile of KCs, intracellular ROS and the mRNA level of pro-inflammatory cytokines were downregulated while the mRNA level of anti-inflammatory cytokine was upregulated by the pretreatment of Curcumin; Then the liver injury was detected by histopathological examination and liver function. Pretreatment with Curcumin significantly alleviated liver injury while improving liver function and overall post-transplantation survival compared with the control groups. The Western blotting showed that Curcumin inhibited the function of KCs via down-regulating the nuclear factor κb (NF-κb) signaling pathway by activating peroxisome proliferator-activated receptor γ (PPARγ) and flow cytometry revealed that Curcumin suppressed pro-inflammatory phenotype (M1) of KCs while promoting its anti-inflammatory phenotype (M2) polarization. These results showed that Curcumin may exert positive effects on I/R injury after OLT through activating PPARγ by inhibiting the activation of NF-κb pathway and remodeling the polarization of KCs. This may reveal a potential therapy for I/R injury after liver transplantation.

Prediction of the endocrine disruption profile of pesticides

Numerous manmade chemicals released into the environment can interfere with normal, hormonally regulated biological processes to adversely affect the development and reproductive functions of living species. Various in vivo and in vitro tests have been designed for detecting endocrine disruptors, but the number of chemicals to test is so high that to save time and money, (quantitative) structure-activity relationship ((Q)SAR) models are increasingly used as a surrogate for these laboratory assays. However, most of them focus only on a specific target (e.g. estrogenic or androgenic receptor) while, to be more efficient, endocrine disruption modelling should preferentially consider profiles of activities to better gauge this complex phenomenon. In this context, an attempt was made to evaluate the endocrine disruption profile of 220 structurally diverse pesticides using the Endocrine Disruptome simulation (EDS) tool, which simultaneously predicts the probability of binding of chemicals on 12 nuclear receptors. In a first step, the EDS web-based system was successfully applied to 16 pharmaceutical compounds known to target at least one of the studied receptors. About 13% of the studied pesticides were estimated to be potential disruptors of the endocrine system due to their high predicted affinity for at least one receptor. In contrast, about 55% of them were unlikely to be endocrine disruptors. The simulation results are discussed and some comments on the use of the EDS tool are made.

Fenofibrate reduces inflammation in obese patients with or without type 2 diabetes mellitus via sirtuin 1/fetuin A axis

AIMS

The aim of the current study is to investigate the effect of fenofibrate alone and in combination with pioglitazone on serum sirtuin 1 and fetuin A of obese patients with Type 2 Diabetes Mellitus (T2DM).

METHODS

Intervention effect on inflammatory parameters was assessed before and after treatment. The study was conducted on 60 postmenopausal females of whom, only 44 patients completed the study. They were distributed as follows; obese patients without T2DM (n=15) who administered fenofibrate (160 mg/day) once for 8 weeks, obese patients with T2DM (n=15) who administered fenofibrate (160 mg/day) once for 8 weeks, obese patients with T2DM (n=14) who administered fenofibrate (160 mg/day) and pioglitazone (15 mg/day) combination once for 8 weeks. We measured fasting plasma glucose, glycated hemoglobin (HbA1c), serum lipids. Inflammatory markers (high sensitivity C-reactive protein "hs-CRP", interleukin-6 "IL-6", fetuin A, and sirtuin 1) of patients were measured in serum using enzyme-linked immunoassay (ELISA) kits.

RESULTS

Sirtuin 1 levels in obese patients with T2DM were significantly lower than its levels in obese patients while fetuin A levels were significantly higher (P<0.001). Fenofibrate, alone and in combination with pioglitazone, significantly decreased triacylglycerol, hs-CRP, IL-6, fetuin A and increased sirtuin 1 levels (P<0.001) which suggests that it can be used to delay the complications of obesity and T2DM. There is a strong correlation between fetuin A, sirtuin 1, IL-6 and hs-CRP levels suggesting a shared common pathway.

CONCLUSIONS

Fenofibrate was shown to increase serum sirtuin 1 and decrease serum fetuin A levels in obese patients.

TRIAL NUMBER

PACTR201407000856135.