The role of various peroxisome proliferator-activated receptors and their ligands in clinical practice

Post-Treatment with Amorfrutin B Evokes PPARγ-Mediated Neuroprotection against Hypoxia and Ischemia

In this study, we demonstrate for the first time that amorfrutin B, a selective modulator of peroxisome proliferator-activated receptor gamma—PPARγ, can protect brain neurons from hypoxia- and ischemia-induced degeneration when applied at 6 h post-treatment in primary cultures. The neuroprotective effect of amorfrutin B suggests that it promotes mitochondrial integrity and is capable of inhibiting reactive oxygen species—ROS activity and ROS-mediated DNA damage. PPARγ antagonist and Pparg mRNA silencing abolished the neuroprotective effect of amorfrutin B, which points to agonistic action of the compound on the respective receptor. Interestingly, amorfrutin B stimulated the methylation of the Pparg gene, both during hypoxia and ischemia. Amorfrutin B also increased the protein level of PPARγ during hypoxia but decreased the mRNA and protein levels of PPARγ during ischemia. Under ischemic conditions, amorfrutin B-evoked hypermethylation of the Pparg gene is in line with the decrease in the mRNA and protein expression of PPARγ. However, under hypoxic conditions, amorfrutin B-dependent hypermethylation of the Pparg gene does not explain the amorfrutin B-dependent increase in receptor protein expression, which suggests other regulatory mechanisms. Other epigenetic parameters, such as HAT and/or sirtuins activities, were affected by amorfrutin B under hypoxic and ischemic conditions. These properties position the compound among the most promising anti-stroke and wide-window therapeutics.

Essential Roles of PPARs in Lipid Metabolism during Mycobacterial Infection

The mycobacterial cell wall is composed of large amounts of lipids with varying moieties. Some mycobacteria species hijack host cells and promote lipid droplet accumulation to build the cellular environment essential for their intracellular survival. Thus, lipids are thought to be important for mycobacteria survival as well as for the invasion, parasitization, and proliferation within host cells. However, their physiological roles have not been fully elucidated. Recent studies have revealed that mycobacteria modulate the peroxisome proliferator-activated receptor (PPAR) signaling and utilize host-derived triacylglycerol (TAG) and cholesterol as both nutrient sources and evasion from the host immune system. In this review, we discuss recent findings that describe the activation of PPARs by mycobacterial infections and their role in determining the fate of bacilli by inducing lipid metabolism, anti-inflammatory function, and autophagy.

Antifibrotic Effects of the Thiazolidinediones in Eosinophilic Esophagitis Pathologic Remodeling: A Preclinical Evaluation

Eosinophilic esophagitis (EoE) is a T-helper 2 (Th2), eosinophilic disease associated with pathologic tissue remodeling that leads to end-organ dysfunction. During early-stage disease, inflammation and subepithelial fibrosis are coupled and reversible, but in late-stage or therapy-resistant disease, there can be uncoupling of these features with progressive esophageal rigidity and strictures contributing to clinical dysphagia and food impactions. No current pharmacotherapeutic interventions directly target esophageal fibrosis. Based on the ability of the thiazolidinediones (TZD) to regulate intestinal and hepatic fibrosis, we tested the antifibrotic effects of the TZDs, rosiglitazone and pioglitazone, in preclinical studies using primary human esophageal fibroblasts.

Liver macrophages and inflammation in physiology and physiopathology of non-alcoholic fatty liver disease

Non‐alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome, being a common comorbidity of type 2 diabetes and with important links to inflammation and insulin resistance. NAFLD represents a spectrum of liver conditions ranging from steatosis in the form of ectopic lipid storage, to inflammation and fibrosis in nonalcoholic steatohepatitis (NASH). Macrophages that populate the liver play important roles in maintaining liver homeostasis under normal physiology and in promoting inflammation and mediating fibrosis in the progression of NAFLD toward to NASH. Liver macrophages are a heterogenous group of innate immune cells, originating from the yolk sac or from circulating monocytes, that are required to maintain immune tolerance while being exposed portal and pancreatic blood flow rich in nutrients and hormones. Yet, liver macrophages retain a limited capacity to raise the alarm in response to danger signals. We now know that macrophages in the liver play both inflammatory and noninflammatory roles throughout the progression of NAFLD. Macrophage responses are mediated first at the level of cell surface receptors that integrate environmental stimuli, signals are transduced through multiple levels of regulation in the cell, and specific transcriptional programmes dictate effector functions. These effector functions play paramount roles in determining the course of disease in NAFLD and even more so in the progression towards NASH. The current review covers recent reports in the physiological and pathophysiological roles of liver macrophages in NAFLD. We emphasise the responses of liver macrophages to insulin resistance and the transcriptional machinery that dictates liver macrophage function.

Network modeling and inference of peroxisome proliferator-activated receptor pathway in high fat diet-linked obesity

Systems biology aims to understand how holistic systems theory can be used to explain the observable living system characteristics, and mathematical modeling tools have been successful in understanding the intricate relationships underlying cellular functions. Lately, researchers have been interested in understanding molecular mechanisms underlying obesity, which is a major health concern worldwide and has been linked to several diseases. Various mechanisms such as peroxisome proliferator-activated receptors (PPARs) are known to modulate obesity-induced inflammation and its consequences. In this study, we have modeled the PPAR pathway using a Bayesian model and inferred the sub-pathways that are potentially responsible for the activation of the output processes that are associated with high fat diet (HFD)-induced obesity. We examined a previously published dataset from a study that compared gene expression profiles of 40 mice maintained on HFD against 40 mice fed with chow diet (CD). Our simulations have highlighted that GPCR and FATCD36 sub-pathways were aberrantly active in HFD mice and are therefore favorable targets for anti-obesity strategies. We further cross-validated our observations with experimental results from the literature. We believe that mathematical models such as those presented in the present study can help in inferring other pathways and deducing significant biological relationships.

Bezafibrate activation of PPAR drives disturbances in mitochondrial redox bioenergetics and decreases the viability of cells from patients with VLCAD deficiency

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is the most common inborn long-chain fatty acid oxidation (FAO) disorder. VLCAD deficiency is characterized by distinct phenotypes. The severe phenotypes are potentially life-threatening and affect the heart or liver, with a comparatively milder phenotype characterized by myopathic symptoms. There is an unmet clinical need for effective treatment options for the myopathic phenotype. The molecular mechanisms driving the gradual decrease in mitochondrial function and associated alterations of muscle fibers are unclear. The peroxisome proliferator-activated receptor (PPAR) pan-agonist bezafibrate is a potent modulator of FAO and multiple other mitochondrial functions and has been proposed as a potential medication for myopathic cases of long-chain FAO disorders. In vitro experiments have demonstrated the ability of bezafibrate to increase VLCAD expression and activity. However, the outcome of small-scale clinical trials has been controversial. We found VLCAD deficient patient fibroblasts to have an increased oxidative stress burden and deranged mitochondrial bioenergetic capacity, compared to controls. Applying heat stress under fasting conditions to bezafibrate pretreated patient cells, caused a marked further increase of mitochondrial superoxide levels. Patient cells failed to maintain levels of the essential thiol peptide antioxidant glutathione and experienced a decrease in cellular viability. Our findings indicate that chronic PPAR activation is a plausible initiator of long-term pathogenesis in VLCAD deficiency. Our findings further implicate disruption of redox homeostasis as a key pathogenic mechanism in VLCAD deficiency and support the notion that a deranged thiol metabolism might be an important pathogenic factor in VLCAD deficiency.

Interaction of BDE-47 with nuclear receptors (NRs) based on the cytotoxicity: In vitro investigation and molecular interaction

Polybrominated diphenyl ethers (PBDEs) are endocrine-disrupting chemicals that possess neuroendocrine and reproductive toxicity to humans and disturb thyroid hormone homeostasis, neurobehavior, and development. The most predominant congener of PBDEs in humans and other organisms is 2,2',4,4'-tetrabromodiphenyl ether (BDE-47); however, the molecular mechanisms underlying its cytotoxicity remain largely unknown. Here, we evaluated the toxic effect and underlying mechanism of nuclear receptors (NRs) induced by BDE-47 in SK-N-SH human neuroblastoma cells. The CCK-8 cell viability assay showed that the proliferation of human SK-N-SH cells exposed to BDE-47 was significantly inhibited in time- and dose-dependent manners, and flow cytometry showed that cell cycle was arrested at the S phase after BDE-47 exposure. Moreover, compared with the control group, the expression of retinoic acid receptor alpha (RXRα), pregnane X receptor (PXR), thyroid hormone receptors (TRs), and peroxisome proliferator-activated receptors (PPARs) at the mRNA and protein levels was significantly increased, as determined by quantitative PCR and western blot analysis, demonstrating that BDE-47 activated the NRs in vitro. Moreover, BDE-47 could bind to all four NRs in the affinity order of PPARγ > PXR > TRβ > RXRα under molecular dynamics. Because RXR is the promiscuous dimerization partner for a large number of NRs, ZDock was used to calculate its interaction with other three NRs. Taking the number of hydrogen bonds and ZDock scores into account, the rank of docking ability between RXRα and the NRs was PXR > TRβ > PPARγ. Further analysis of the interaction between BDE-47 and dimerized-NRs, the affinity order was RXRα > TRβ > PXR > PPARγ via Glide. The results of this study demonstrated that BDE-47 interfered the cross-talk among NRs, especially the promiscuous RXRα, which might be critical for the harmonized re-adjustment of cytotoxicity and biological regulation. Our findings provide a better understanding of the mechanisms underlying toxic effects and intermolecular interaction induced by BDE-47.

Role of Peroxisome Proliferator-Activated Receptors (PPARs) in Trophoblast Functions

Peroxisome proliferator-activated receptors (PPARα, PPARβ/δ, and PPARγ) belong to the transcription factor family, and they are highly expressed in all types of trophoblast during pregnancy. The present review discusses currently published papers that are related to the regulation of PPARs via lipid metabolism, glucose metabolism, and amino acid metabolism to affect trophoblast physiological conditions, including differentiation, maturation, secretion, fusion, proliferation, migration, and invasion. Recent pieces of evidence have proven that the dysfunctions of PPARs in trophoblast lead to several related pregnancy diseases such as recurrent miscarriage, preeclampsia, intrauterine growth restriction, and gestational diabetes mellitus. Moreover, the underlying mechanisms of PPARs in the control of these processes have been discussed as well. Finally, this review's purposes are to provide more knowledge about the role of PPARs in normal and disturbed pregnancy with trophoblast, so as to find PPAR ligands as a potential therapeutic target in the treatment and prevention of adverse pregnancy outcomes.

Selective Peroxisome Proliferator-Activated Receptor Alpha Modulators (SPPARMα) in the Metabolic Syndrome: Is Pemafibrate Light at the End of the Tunnel?

Purpose of Review

Adoption of poor lifestyles (inactivity and energy-dense diets) has driven the worldwide increase in the metabolic syndrome, type 2 diabetes mellitus and non-alcoholic steatohepatitis (NASH). Of the defining features of the metabolic syndrome, an atherogenic dyslipidaemia characterised by elevated triglycerides (TG) and low plasma concentration of high-density lipoprotein cholesterol is a major driver of risk for atherosclerotic cardiovascular disease. Beyond lifestyle intervention and statins, targeting the nuclear receptor peroxisome proliferator-activated receptor alpha (PPARα) is a therapeutic option. However, current PPARα agonists (fibrates) have limitations, including safety issues and the lack of definitive evidence for cardiovascular benefit. Modulating the ligand structure to enhance binding at the PPARα receptor, with the aim of maximising beneficial effects and minimising adverse effects, underlies the SPPARMα concept.

Recent Findings

This review discusses the history of SPPARM development, latterly focusing on evidence for the first licensed SPPARMα, pemafibrate. Evidence from animal models of hypertriglyceridaemia or NASH, as well as clinical trials in patients with atherogenic dyslipidaemia, are overviewed.

Summary

The available data set the scene for therapeutic application of SPPARMα in the metabolic syndrome, and possibly, NASH. The outstanding question, which has so far eluded fibrates in the setting of current evidence-based therapy including statins, is whether treatment with pemafibrate significantly reduces cardiovascular events in patients with atherogenic dyslipidaemia. The PROMINENT study in patients with type 2 diabetes mellitus and this dyslipidaemia is critical to evaluating this.

Adipogenesis as a Potential Anti-Obesity Target: A Review of Pharmacological Treatment and Natural Products

Obesity is recognized as a severe threat to overall human health and is associated with type 2 diabetes mellitus, dyslipidemia, hypertension, and cardiovascular diseases. Abnormal expansion of white adipose tissue involves increasing the existing adipocytes' cell size or increasing the number through the differentiation of new adipocytes. Adipogenesis is a process of proliferation and differentiation of adipocyte precursor cells in mature adipocytes. As a key process in determining the number of adipocytes, it is a possible therapeutic approach for obesity. Therefore, it is necessary to identify the molecular mechanisms involved in adipogenesis that could serve as suitable therapeutic targets. Reducing bodyweight is regarded as a major health benefit. Limited efficacy and possible side effects and drug interactions of available anti-obesity treatment highlight a constant need for finding novel efficient and safe anti-obesity ingredients. Numerous studies have recently investigated the inhibitory effects of natural products on adipocyte differentiation and lipid accumulation. Possible anti-obesity effects of natural products include the induction of apoptosis, cell-cycle arrest or delayed progression, and interference with transcription factor cascade or intracellular signaling pathways during the early phase of adipogenesis.

Nonalcoholic steatohepatitis: the role of peroxisome proliferator-activated receptors

The increasing epidemic of obesity worldwide is linked to serious health effects, including increased prevalence of type 2 diabetes mellitus, cardiovascular disease and nonalcoholic fatty liver disease (NAFLD). NAFLD is the liver manifestation of the metabolic syndrome and includes the spectrum of liver steatosis (known as nonalcoholic fatty liver) and steatohepatitis (known as nonalcoholic steatohepatitis), which can evolve into progressive liver fibrosis and eventually cause cirrhosis. Although NAFLD is becoming the number one cause of chronic liver diseases, it is part of a systemic disease that affects many other parts of the body, including adipose tissue, pancreatic β-cells and the cardiovascular system. The pathomechanism of NAFLD is multifactorial across a spectrum of metabolic derangements and changes in the host microbiome that trigger low-grade inflammation in the liver and other organs. Peroxisome proliferator-activated receptors (PPARs) are a group of nuclear regulatory factors that provide fine tuning for key elements of glucose and fat metabolism and regulate inflammatory cell activation and fibrotic processes. This Review summarizes and discusses the current literature on NAFLD as the liver manifestation of the systemic metabolic syndrome and focuses on the role of PPARs in the pathomechanisms as well as in the potential targeting of disease.

Peroxisome proliferator-activated receptors in the pathogenesis and therapies of liver fibrosis

Liver fibrosis is a dynamic wound-healing process associated with the deposition of extracellular matrix produced by myofibroblasts. HSCs activation, inflammation, oxidative stress, steatosis and aging play critical roles in the progression of liver fibrosis, which is correlated with the regulation of the peroxisome proliferator-activated receptor (PPAR) pathway. As nuclear receptors, PPARs reduce inflammatory response, regulate lipid metabolism, and inhibit fibrogenesis in the liver associated with aging. Thus, PPAR ligands have been investigated as possible therapeutic agents. Mounting evidence indicated that some PPAR agonists could reverse steatohepatitis and liver fibrosis. Consequently, targeting PPARs might be a promising and novel therapeutic option against liver fibrosis. This review summarizes recent studies on the role of PPARs on the pathogenesis and treatment of liver fibrosis.

A Novel N-Substituted Valine Derivative with Unique Peroxisome Proliferator-Activated Receptor γ Binding Properties and Biological Activities

A proprietary library of novel N-aryl-substituted amino acid derivatives bearing a hydroxamate head group allowed the identification of compound 3a that possesses weak proadipogenic and peroxisome proliferator-activated receptor γ (PPARγ) activating properties. The systematic optimization of 3a, in order to improve its PPARγ agonist activity, led to the synthesis of compound 7j (N-aryl-substituted valine derivative) that possesses dual PPARγ/PPARα agonistic activity. Structural and kinetic analyses reveal that 7j occupies the typical ligand binding domain of the PPARγ agonists with, however, a unique high-affinity binding mode. Furthermore, 7j is highly effective in preventing cyclin-dependent kinase 5-mediated phosphorylation of PPARγ serine 273. Although less proadipogenic than rosiglitazone, 7j significantly increases adipocyte insulin-stimulated glucose uptake and efficiently promotes white-to-brown adipocyte conversion. In addition, 7j prevents oleic acid-induced lipid accumulation in hepatoma cells. The unique biochemical properties and biological activities of compound 7j suggest that it would be a promising candidate for the development of compounds to reduce insulin resistance, obesity, and nonalcoholic fatty liver disease.

Treatment for eosinophilic esophagitis

PURPOSE OF REVIEW

To summarize current dietary and pharmacologic approaches in the treatment of eosinophilic esophagitis (EoE).

RECENT FINDINGS

Studies comparing dietary approaches in EoE treatment support empiric elimination diets as the preferred approach to dietary EoE treatment, with no data to support use of currently available allergy tests to guide specific food elimination diets. Swallowed topical corticosteroid therapy is the current standard of care in pharmacologic EoE treatment, with similar effectiveness of fluticasone and budesonide, but their discontinuation results in return of both EoE symptoms and disease. A number of nonsteroid-based therapies are currently under investigation for the treatment of EoE, which are focused on targeting disease at a cellular level.

SUMMARY

EoE can be treated with diet or medications. Empiric elimination is presently the preferred dietary approach. Swallowed steroids is the standard of care to treat EoE with medication; however, there are several promising drugs currently undergoing clinical trials.

High-Fat Diet-Induced Functional and Pathologic Changes in Lacrimal Gland

The lacrimal gland is critical for maintaining the homeostasis of the ocular surface microenvironment through secreting aqueous tears in mammals. Many systemic diseases such as Sjögren syndrome, rheumatoid arthritis, and diabetes can alter the lacrimal gland function, eventually resulting in aqueous tear-deficient dry eye. Here, a high-fat diet (HFD) experimental mouse model was used to clarify how hyperlipidemia affects lacrimal gland function. Aqueous tear secretion fell about 50% after 1 month on a HFD. Lipid droplets accumulated in the matrix and acinar cells of the lacrimal gland after this period, along with changes in the lipid metabolism, changes in gene expression levels, and disruption of fatty acid oxidative activity. Immune cell infiltration and rises in the gene expression levels of the inflammation-related cytokines Il1β, Tnfα, Tsg6, Il10, Mmp2, and Mmp9 were found. HFD also induced mitochondrial hypermegasoma, increased apoptosis, and decreased lacrimal gland acinar cell proliferation. Replacement of the HFD with the standard diet partially reversed pathologic changes in the lacrimal gland. Similarly, supplementing the HFD with fenofibrate also partially reversed the inhibited tear secretion and reduced lipid accumulation, inflammation, and oxidative stress levels. The authors conclude that a HFD induces pathophysiological changes and functional decompensation of the lacrimal gland. Therefore, ingestion of a HFD may be a causative factor of dry eye disease.

The roles of PPARγ and its agonists in autoimmune diseases: A comprehensive review

Autoimmune diseases are common diseases of the immune system that are characterized by the loss of self-tolerance and the production of autoantibodies; the breakdown of immune tolerance and the prolonged inflammatory reaction are undisputedly core steps in the initiation and maintenance of autoimmunity. Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors that belong to the nuclear hormone receptor family and act as ligand-activated transcription factors. There are three different isotypes of PPARs: PPARα, PPARγ, and PPARβ/δ. PPARγ is an established regulator of glucose homeostasis and lipid metabolism. Recent studies have demonstrated that PPARγ exhibits anti-inflammatory and anti-fibrotic effects in multiple disease models. PPARγ can also modulate the activation and polarization of macrophages, regulate the function of dendritic cells and mediate T cell survival, activation, and differentiation. In this review, we summarize the signaling pathways and biological functions of PPARγ and focus on how PPARγ and its agonists play protective roles in autoimmune diseases, including autoimmune thyroid diseases, multiple sclerosis, rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus, primary Sjogren syndrome and primary biliary cirrhosis.

Review article: the impact of liver-directed therapies on the atherogenic risk profile in non-alcoholic steatohepatitis

BACKGROUND

Patients with non-alcoholic fatty liver disease (NAFLD), the most common cause of chronic liver disease, are at higher risk of cardiovascular disease (CVD) and associated mortality. Therefore, it is important to understand how new therapies for non-alcoholic steatohepatitis (NASH) may impact CVD risk factors in these patients.

AIMS

To summarise the effects of drug therapies on lipid and lipoprotein levels in patients with NASH and provide insight into the potential mechanisms for the observed changes.

METHODS

PubMed searches of the literature were performed and results were compiled.

RESULTS

Recent clinical trials have highlighted the safety and efficacy of drug candidates for the treatment of NASH. Several agents have shown improvements in the histological features of NASH and liver function. Pioglitazone, a drug that is currently available for type 2 diabetes and may be useful for NASH, exhibits beneficial effects on lipids. However, agents such as farnesoid X receptor agonists, which are in development for NASH, may adversely affect circulating lipids and lipoproteins.

CONCLUSIONS

NASH is a multi-system disease with a disproportionate CVD burden. Current and future drugs for NASH have had variable impact on the atherogenic risk profile. Potential co-administration of a statin may help mitigate the negative impact of some of these therapies on lipid and lipoprotein levels.

Peroxisome proliferator activated receptor γ promotes mineralization and differentiation in cementoblasts via inhibiting Wnt/β-catenin signaling pathway

Peroxisome proliferator activated receptor γ (PPARγ) is a member of the nuclear receptor family of transcription factors, which involved in inflammation regulating and bone remodeling. Rare studies explored the effects of PPARγ on mineralization and differentiation in cementoblasts. To explore the potential approaches to repair the damaged periodontal tissues especially for cementum, the present study aims to investigate the effects and the regulating mechanism of PPARγ on mineralization and differentiation in cementoblasts. Murine cementoblast cell lines (OCCM-30) were cultured in basic medium for 24 hours/48 hours or in mineralization medium for 3/7/10 days, respectively at addition of dimethyl sulphoxide, rosiglitazone (PPARγ agonist), GW9662 (PPARγ antagonist), lithium chloride (LiCl), tumor necrosis factor-α (TNF-α), or respective combination. Expression of mineralization genes alkaline phosphatase (ALP), runt related transcription factors 2 (RUNX2), and osteocalcin (OCN) were detected by quantitative real-time polymerase chain reaction or/and Western blot. ALP staining and alizarin red staining were used to evaluate the mineralization in OCCM-30 cells. The change of β-catenin expression and translocation in cytoplasm/nucleus was analyzed by Western blot and immunofluorescence. The results showed that PPARγ agonist rosiglitazone improved the expression of ALP, RUNX2, and OCN, deepened ALP staining, increased mineralized nodules formation, and decreased β-catenin expression in the nucleus. LiCl, an activator of the Wnt signaling pathway, inhibited the expression of mineralization genes and reversed the upregulated expression of mineralization genes resulted from rosiglitazone. Under inflammatory microenvironment, rosiglitazone not only suppressed the expression of interleukin-1β caused by TNF-α, but improved the expression of mineralization genes in OCCM-30 cells. In conclusion, PPARγ could promote mineralization and differentiation in cementoblasts via inhibiting the Wnt/β-catenin signaling pathway, which would shed new light on the treatment of periodontitis and periodontal tissue regeneration.

Peroxisome Proliferator-Activated Receptor Beta/Delta Agonist Suppresses Inflammation and Promotes Neovascularization

The effects of peroxisome proliferator-activated receptor (PPAR)β/δ ophthalmic solution were investigated in a rat corneal alkali burn model. After alkali injury, GW501516 (PPARβ/δ agonist) or vehicle ophthalmic solution was topically instilled onto the rat’s cornea twice a day until day 7. Pathological findings were evaluated, and real-time reverse transcription polymerase chain reaction was performed. GW501516 strongly suppressed infiltration of neutrophils and pan-macrophages, and reduced the mRNA expression of interleukin-6, interleukin-1β, tumor necrosis factor alpha, and nuclear factor-kappa B. On the other hand, GW501516 promoted infiltration of M2 macrophages, infiltration of vascular endothelial cells associated with neovascularization in the wounded area, and expression of vascular endothelial growth factor A mRNA. However, 7-day administration of GW501516 did not promote neovascularization in uninjured normal corneas. Thus, the PPARβ/δ ligand suppressed inflammation and promoted neovascularization in the corneal wound healing process. These results will help to elucidate the role of PPARβ/δ in the field of ophthalmology.

Probiotic Bifidobacterium lactis V9 attenuates hepatic steatosis and inflammation in rats with non-alcoholic fatty liver disease

Both steatosis and inflammation are key pathological events in the progression of non-alcoholic fatty liver disease (NAFLD). Probiotics are beneficial for the prevention and treatment of NAFLD. Bifidobacterium animalis subsp. lactis V9 (V9) is a newly isolated strain with favorable probiotic properties. The study aims to evaluate the effects and mechanisms of V9 on the hepatic steatosis and inflammatory responses in a rat model of NAFLD induced by high-fat diets (HFD). Our results showed that administration of V9 significantly attenuated the HFD-induced increases in alanine transaminase (ALT) and aspartate aminotransferase (AST) levels, resulting in alleviated hepatic steatosis. V9 supplementation reduced the accumulation of hepatic triglyceride and free fatty acid,while increasing the levels of glycogen. Serum levels of glucose were also decreased in HFD rats administrated with V9. Meanwhile, the transcription of SREBP-1c and FAS was reduced, and the hepatic expression of phosphorylated-AMPK and PPAR-α was restored after V9 administration. V9 suppressed the production of inflammatory cytokines (e.g. IL-6, IL-1β, and TNF-α) in HFD-fed rats. The anti-inflammatory effects of V9 was found to be associated with the inhibition of hepatic expression of TLR4, TLR9, NLRP3, and ASC mRNA. Furthermore, the activation of ERK, JNK, AKT and NF-κB were suppressed by V9 treatment. These results indicate that Bifidobacterium lactis V9 improves NAFLD by regulating de novo lipid synthesis and suppressing inflammation through AMPK and TLR-NF-κB pathways, respectively.

The role of PPARα in autosomal dominant polycystic kidney disease

PURPOSE OF REVIEW

Metabolic reprogramming is a prominent feature of cyst epithelial cells in autosomal dominant polycystic kidney disease (ADPKD). Peroxisome proliferator activated receptor alpha (PPARα) is a transcription factor that regulates many aspects of cellular metabolism. The purpose of this review is to understand the role of PPARα in ADPKD.

RECENT FINDINGS

PPARα expression is reduced in ADPKD kidneys of mice and humans. This downregulation is in part secondary to microRNA mediated translational repression and leads to impairment of fatty acid metabolism. Genetic studies demonstrate that deletion of Pparα aggravates cyst growth in a slowly progressive mouse model of ADPKD. Recent studies also show that administration of Pparα agonists ameliorates cyst burden in mice.

SUMMARY

Abnormal reduction of PPARα affects cellular metabolism in ADPKD. Pparα is a modulator of cyst progression in mouse models of ADPKD. These studies establish PPARα as an exciting new drug target for the treatment of individuals with ADPKD.

Gut-Derived Serotonin Contributes to the Progression of Non-Alcoholic Steatohepatitis via the Liver HTR2A/PPARγ2 Pathway

The precipitous increase in occurrence of non-alcoholic steatohepatitis (NASH) is a serious threat to public health worldwide. The pathogenesis of NASH has not yet been thoroughly studied. We aimed to elucidate the interplay between serotonin (5-hydroxytryptamine, 5-HT) and NASH. The serum 5-HT levels in patients with non-alcoholic fatty liver disease (NAFLD) and a rat fed with high fat-sucrose diet (HFSD) were evaluated using liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF MS)/MS. The peripheral Tph1 inhibitor, LP533401, and a tryptophan (TRP)-free diet were administered to rats with NASH, induced by HFSD. BRL-3A cells were treated with 1 mM free fatty acids (FFAs) and/or 50 μM 5-HT, and then small interfering RNA (siRNA) targeting the 5-HT2A receptor (HTR2A) and the PPARγ pharmaceutical agonist, pioglitazone, were applied. We found a marked correlation between 5-HT and NASH. The absence of 5-HT, through the pharmaceutical blockade of Tph1 (LP533401) and dietary control (TRP-free diet), suppressed hepatic lipid load and the expression of inflammatory factors (Tnfα, Il6, and Mcp-1). In BRL-3A cells, 50 μM 5-HT induced lipid accumulation and upregulated the expression of lipogenesis-ralated genes (Fas, Cd36, and Plin2) and the inflammatory response. Specifically, HTR2A knockdown and evaluation of PPARγ agonist activity revealed that HTR2A promoted hepatic steatosis and inflammation by activating PPARγ2. These results suggested that duodenal 5-HT was a risk factor in the pathological progression of NASH. Correspondingly, it may represent an attractive therapeutic target for preventing the development of NASH via the regulation of the HTR2A/PPARγ2 signaling pathway.

Novel therapeutics in hypertriglyceridaemia and chylomicronaemia

Currently there is evidence on hypertriglyceridaemia as an independent risk factor of atherosclerosis. Chylomicronaemia associated with very high concentration of triglycerides may cause severe and recurrent acute pancreatitis. The cause of most cases is a combination of a polygenetic basis with some lifestyles and pathological conditions. Some rare and familial chylomicronaemias are mendelian diseases with an autosomal recessive pattern. On the other hand, plasma triglycerides have considerable biological variability and usually descend with non-pharmacological interventions alone. In some cases, drugs are also required for their control, but their impact on vascular risk reduction or pancreatitis prevention is more controversial. The recent advances in knowledge of molecular lipid metabolism and pharmacological technologies are resulting in the development of new therapeutic strategies, which can be applied to patients with refractory hypertrigliceridaemia. The challenge may be how the health systems can cover its high costs.

Topical Pioglitazone Nanoformulation for the Treatment of Atopic Dermatitis: Design, Characterization and Efficacy in Hairless Mouse Model

Pioglitazone (PGZ) is a drug used to treat type 2 diabetes mellitus that has been reported to show additional therapeutic activities on diverse inflammatory parameters. The aim of this study was to optimize a topical PGZ-loaded nanoemulsion (PGZ-NE) in order to evaluate its effectiveness for treating atopic dermatitis (AD). The composition of the nanoformulation was established by pseudo-ternary diagram. Parameters such as physical properties, stability, in vitro release profile, and ex vivo permeation were determined. The efficacy study was carried out using oxazolone-induced AD model in hairless mice. PGZ-NE released the drug following a hyperbolic kinetic. Additionally, its properties provided high retention potential of drug inside the skin. Therapeutic benefits of PGZ-NE were confirmed on diverse events of the inflammatory process, such as reduction of lesions, enhancement of skin barrier function, diminished infiltration of inflammatory cells, and expression of pro-inflammatory cytokines. These results were reinforced by atomic force microscope (AFM), which demonstrated the ability of the formulation to revert the rigidification caused by oxazolone and consequently improve the elasticity of the skin. These results suggest that PGZ-NE may be a promising treatment for inflammatory dermatological conditions such as AD.

Activation of the Metabolic Master Regulator PPARγ: A Potential PIOneering Therapy for Pulmonary Arterial Hypertension

Translational research is essential to the development of reverse-remodeling strategies for the treatment of pulmonary vascular disease, pulmonary hypertension, and heart failure via mechanistic in vivo studies using animal models resembling human pulmonary arterial hypertension (PAH), cardiovascular remodeling, and progressive right heart failure. Since 2007, peroxisome proliferator-activated receptor γ (PPARγ) agonists have emerged as promising novel, antiproliferative, antiinflammatory, insulin-sensitizing, efficient medications for the treatment of PAH. However, early diabetes study results, their subsequent misinterpretations, errors in published review articles, and rumors regarding potential adverse effects in the literature have dampened enthusiasm for considering pharmacological PPARγ activation for the treatment of cardiovascular diseases, including PAH. Most recently, the thiazolidinedione class PPARγ agonist pioglitazone underwent a clinical revival, especially based on the IRIS (Insulin Resistance Intervention After Stroke) study, a randomized controlled trial in 3,876 patients without diabetes status post-transient ischemic attack/ischemic stroke who were clinically followed for 4.8 years. We discuss preclinical basic translational findings and randomized controlled trials related to the beneficial and adverse effects of PPARγ agonists of the thiazolidinedione class, with a particular focus on the last 5 years. The objective is a data-driven approach to set the preclinical and clinical study record straight. The convincing recent clinical trial data on the lack of significant toxicity in high-risk populations justify the timely conduct of clinical studies to achieve "repurposing" or "repositioning" of pioglitazone for the treatment of clinical PAH.

Peroxisome Proliferator-Activated Receptors as a Therapeutic Target in Asthma

The complexity of the pathogenetic mechanisms of the development of chronic inflammation in asthma determines its heterogeneity and insufficient treatment effectiveness. Nuclear transcription factors, which include peroxisome proliferator-activated receptors, that is, PPARs, play an important role in the regulation of initiation and resolution of the inflammatory process. The ability of PPARs to modulate not only lipid homeostasis but also the activity of the inflammatory response makes them an important pathogenetic target in asthma therapy. At present, special attention is focused on natural (polyunsaturated fatty acids (PUFAs), endocannabinoids, and eicosanoids) and synthetic (fibrates, thiazolidinediones) PPAR ligands and the study of signaling mechanisms involved in the implementation of their anti-inflammatory effects in asthma. This review summarizes current views on the structure and function of PPARs, as well as their participation in the pathogenesis of chronic inflammation in asthma. The potential use of PPAR ligands as therapeutic agents for treating asthma is under discussion.

Pharmacological effects of icariin

Icariin (ICA) is a principal active component from traditional Chinese medicine Epimedium grandiflorum. To explain its traditional medical usages by modern science, a variety of pharmacological effects have been studied for ICA. In this review, we summarized the pharmacokinetics of ICA as well as its pharmacological mechanisms in neurodegenerative disease, cardiovascular disease, anti-osteoporosis, anti-inflammation, anti-oxidative stress, anti-depression and anti-tumors.

In vivo liposomal delivery of PPARα/γ dual agonist tesaglitazar in a model of obesity enriches macrophage targeting and limits liver and kidney drug effects

Macrophages are important regulators of obesity-associated inflammation and PPARα and -γ agonism in macrophages has anti-inflammatory effects. In this study, we tested the efficacy with which liposomal delivery could target the PPARα/γ dual agonist tesaglitazar to macrophages while reducing drug action in common sites of drug toxicity: the liver and kidney, and whether tesaglitazar had anti-inflammatory effects in an in vivo model of obesity-associated dysmetabolism. Methods: Male leptin-deficient (ob/ob) mice were administered tesaglitazar or vehicle for one week in a standard oral formulation or encapsulated in liposomes. Following the end of treatment, circulating metabolic parameters were measured and pro-inflammatory adipose tissue macrophage populations were quantified by flow cytometry. Cellular uptake of liposomes in tissues was assessed using immunofluorescence and a broad panel of cell subset markers by flow cytometry. Finally, PPARα/γ gene target expression levels in the liver, kidney, and sorted macrophages were quantified to determine levels of drug targeting to and drug action in these tissues and cells. Results: Administration of a standard oral formulation of tesaglitazar effectively treated symptoms of obesity-associated dysmetabolism and reduced the number of pro-inflammatory adipose tissue macrophages. Macrophages are the major cell type that took up liposomes with many other immune and stromal cell types taking up liposomes to a lesser extent. Liposome delivery of tesaglitazar did not have effects on inflammatory macrophages nor did it improve metabolic parameters to the extent of a standard oral formulation. Liposomal delivery did, however, attenuate effects on liver weight and liver and kidney expression of PPARα and -γ gene targets compared to oral delivery. Conclusions: These findings reveal for the first time that tesaglitazar has anti-inflammatory effects on adipose tissue macrophage populations in vivo. These data also suggest that while nanoparticle delivery reduced off-target effects, yet the lack of tesaglitazar actions in non-targeted cells such (as hepatocytes and adipocytes) and the uptake of drug-loaded liposomes in many other cell types, albeit to a lesser extent, may have impacted overall therapeutic efficacy. This fulsome analysis of cellular uptake of tesaglitazar-loaded liposomes provides important lessons for future studies of liposome drug delivery.

Progress in promising anti-fibrotic therapies

Introduction: Liver cirrhosis is the most deleterious consequence of chronic liver diseases of different etiologies. Progression of liver diseases to cirrhosis, irrespective of etiology, involves chronic parenchymal injury, persistent activation of inflammatory response, sustained activation of fibrogenesis and wound-healing response. Despite intensive research on antifibrotic drugs, novel therapeutics specifically for liver have not been yet licensed. This review will examine compounds currently under development and key challenges in specific settings as for example that of NAFLD associated fibrosis.Areas covered: Results of the main phase II and III trial, including those with negative results, are presented and discussed. The endpoints selected and their limitations highlighted in order to suggest potential options to move forward.Expert opinion: Strategies based on single-molecule targets, associated so far with some disappointing results, may be unlikely to succeed in the context of such complex pathogenesis. Blocking at the same time different pathways that drive fibrosis progression may be required to provide significant benefit.

Determination of the effects of torularhodin against alcoholic liver diseases by transcriptome analysis

Alcoholic liver disease (ALD) is a major cause of liver injury worldwide. Oxidative damage is one of the main injuries caused by ALD. The aim of this study was to elucidate the preventive effects of torularhodin, extracted from Sporidiobolus pararoseus, on alcoholic liver injury in mice. The mechanisms involved were investigated using transcriptome analysis. Torularhodin supplementation decreased ethanol-induced aspartate transaminase (ALT), aspartate transaminase (AST) and low density lipoprotein (LDL) levels, and increased high density lipoprotein (HDL) levels in the serum of mice. In liver tissue, treatment with torularhodin increased ethanol-induced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels and decreased tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels. Histological analysis showed that torularhodin could alleviate the negative effects of alcohol on the liver. Transcriptomic analysis showed that 806 genes were significantly differentially expressed (506 up-regulated and 300 down-regulated) after torularhodin treatment. These genes were involved in three main Gene Ontology categories (biological process, cellular component, and molecular function) and multiple pathways. Therefore, torularhodin was considered to have potential as a protective agent against ALD.

Lifestyle and Food Habits Impact on Chronic Diseases: Roles of PPARs

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that exert important functions in mediating the pleiotropic effects of diverse exogenous factors such as physical exercise and food components. Particularly, PPARs act as transcription factors that control the expression of genes implicated in lipid and glucose metabolism, and cellular proliferation and differentiation. In this review, we aim to summarize the recent advancements reported on the effects of lifestyle and food habits on PPAR transcriptional activity in chronic disease.

Effect of High-Fat Diets on Oxidative Stress, Cellular Inflammatory Response and Cognitive Function

Cognitive dysfunction is linked to chronic low-grade inflammatory stress that contributes to cell-mediated immunity in creating an oxidative environment. Food is a vitally important energy source; it affects brain function and provides direct energy. Several studies have indicated that high-fat consumption causes overproduction of circulating free fatty acids and systemic inflammation. Immune cells, free fatty acids, and circulating cytokines reach the hypothalamus and initiate local inflammation through processes such as microglial proliferation. Therefore, the role of high-fat diet (HFD) in promoting oxidative stress and neurodegeneration is worthy of further discussion. Of particular interest in this article, we highlight the associations and molecular mechanisms of HFD in the modulation of inflammation and cognitive deficits. Taken together, a better understanding of the role of oxidative stress in cognitive impairment following HFD consumption would provide a useful approach for the prevention of cognitive dysfunction.

PPARs as Nuclear Receptors for Nutrient and Energy Metabolism

It has been more than 36 years since peroxisome proliferator-activated receptors (PPARs) were first recognized as enhancers of peroxisome proliferation. Consequently, many studies in different fields have illustrated that PPARs are nuclear receptors that participate in nutrient and energy metabolism and regulate cellular and whole-body energy homeostasis during lipid and carbohydrate metabolism, cell growth, cancer development, and so on. With increasing challenges to human health, PPARs have attracted much attention for their ability to ameliorate metabolic syndromes. In our previous studies, we found that the complex functions of PPARs may be used as future targets in obesity and atherosclerosis treatments. Here, we review three types of PPARs that play overlapping but distinct roles in nutrient and energy metabolism during different metabolic states and in different organs. Furthermore, research has emerged showing that PPARs also play many other roles in inflammation, central nervous system-related diseases, and cancer. Increasingly, drug development has been based on the use of several selective PPARs as modulators to diminish the adverse effects of the PPAR agonists previously used in clinical practice. In conclusion, the complex roles of PPARs in metabolic networks keep these factors in the forefront of research because it is hoped that they will have potential therapeutic effects in future applications.

Cardiovascular, electrophysiologic, and hematologic effects of omega-3 fatty acids beyond reducing hypertriglyceridemia: as it pertains to the recently published REDUCE-IT trial

Heart disease continues to affect health outcomes globally, accounting for a quarter of all deaths in the United States. Despite the improvement in the development and implementation of guideline-directed medical therapy, the risk of adverse cardiac events remains substantially high. Historically, it has been debated whether omega-3 polyunsaturated fatty acids provide clinical benefit in cardiac disease. The recently published REDUCE-IT trial demonstrated a statistically significant absolute risk reduction of 4.8% in its primary endpoint (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, or unstable angina) with the use of icosapent ethyl, which is a highly purified eicosapentaenoic acid (EPA) ethyl ester. However, the mechanism of action of omega-3 fatty acids is not commonly discussed. Moreover, the use of EPA was not without risk, as the incidence of atrial fibrillation was increased along with a trend towards increased bleeding risk. Thus, our aim is to help explain the function of purified EPA ethyl ester, especially at the molecular level, which will ultimately lead to a better understanding of their clinically observable effects.

The Role of Nuclear Receptors in Prostate Cancer

The nuclear receptor (NR) superfamily consists of 48 members that are divided into seven subfamilies. NRs are transcription factors that play an important role in a number of biological processes. The NR superfamily includes androgen receptor, which is a key player in prostate cancer pathogenesis, suggesting the functional roles of other NRs in prostate cancer. The findings on the roles of NRs in prostate cancer thus far have shown that several NRs such as vitamin D receptor, estrogen receptor β, and mineralocorticoid receptor play antioncogenic roles, while other NRs such as peroxisome proliferator-activated receptor γ and estrogen receptor α as well as androgen receptor play oncogenic roles. However, the roles of other NRs in prostate cancer remain controversial or uninvestigated. Further research on the role of NRs in prostate cancer is required and may lead to the development of novel preventions and therapeutics for prostate cancer.

PPAR Ligands Containing Stilbene Scaffold

Peroxisome proliferator-activated receptors (PPARs) are transcriptional factors which belong to the ligand-activated nuclear receptor superfamily. They are ubiquitously expressed throughout the body. So far, three major subtypes have been identified, PPARα, PPARβ/δ and PPARγ. They are crucial for lipid and glucose metabolism and are also involved in the regulation of several types of tumors, inflammation, cardiovascular diseases and infertility. The importance of these transcription factors in physiology and pathophysiology has been largely investigated. Synthetic PPAR ligands are widely used in the treatment of dyslipidemia (e.g. fibrates - PPARα activators) or in diabetes mellitus (e.g. thiazolidinediones - PPARγ agonists) while a new generation of dual agonists reveals hypolipemic, hypotensive, antiatherogenic, anti-inflammatory and anticoagulant action. Many natural ligands, including polyphenolic compounds, influence the expression of these receptors. They have several health-promoting properties, including antioxidant, anti-inflammatory, and antineoplastic activities. Resveratrol, a stilbene polyphenol, is a biological active modulator of several signaling proteins, including PPARs. Given the enormous pharmacological potential of resveratrol, stilbene-based medicinal chemistry had a rapid increase covering various areas of research. The present review discusses ligands of PPARs that contain stilbene scaffold and summarises the different types of compounds on the basis of chemical structure.

Epigenetic Alternations of MicroRNAs and DNA Methylation Contribute to Liver Metastasis of Colorectal Cancer

BACKGROUND

Liver metastasis is a major cause of mortality in colorectal cancer (CRC). Epigenetic alternations could serve as biomarkers for cancer diagnosis and prognosis. In this study, we analyzed microarray data in order to identify core genes and pathways which contribute to liver metastasis in CRC under epigenetic regulations.

MATERIALS AND METHODS

Data of miRNAs (GSE35834, GSE81582), DNA methylation (GSE90709, GSE77955), and mRNA microarrays (GSE68468, GSE81558) were downloaded from GEO database. Differentially expressed genes (DEGs), differentially expressed miRNAs (DEMs), and differentially methylated genes (DMGs) were obtained by GEO2R. The target genes of DEMs were predicted by miRWalk. Functional and enrichment analyses were conducted by DAVID database. Protein-protein interaction (PPI) network was constructed in STRING and visualized using Cytoscape.

RESULTS

In liver metastasis, miR-143-3p, miR-10b-5p, miR-21-5p, and miR-518f-5p were down-regulated, while miR-122-5p, miR-885-5p, miR-210-3p, miR-130b-5p, miR-1275, miR-139-5p, miR-139-3p, and miR-1290 were up-regulated compared with primary CRC. DEGs targeted by altered miRNAs were enriched in pathways including complement, PPAR signaling, ECM-receptor interaction, spliceosome, and focal adhesion. In addition, aberrant DNA methylation-regulated genes showed enrichment in pathways of amino acid metabolism, calcium signaling, TGF-beta signaling, cell cycle, spliceosome, and Wnt signaling.

CONCLUSION

Our study identified a series of differentially expressed genes which are associated with epigenetic alternations of miRNAs and DNA methylation in colorectal liver metastasis. Up-regulated genes of SLC10A1, MAPT, SHANK2, PTH1R, and C2, as well as down-regulated genes of CAB39, CFLAR, CTSC, THBS1, and TRAPPC3 were associated with both miRNA and DNA methylation, which might become promising biomarker of colorectal liver metastasis in future.

Group 1 innate lymphoid cells are involved in the progression of experimental anti-glomerular basement membrane glomerulonephritis and are regulated by peroxisome proliferator-activated receptor α

Innate lymphoid cells play an important role in the early effector cytokine-mediated response. In Wistar Kyoto rats, CD8⁺ non-T lymphocytes (CD8⁺Lym) infiltrate into glomeruli during the development of anti-glomerular basement membrane (anti-GBM) glomerulonephritis. Here, we examined the profiles and roles of CD8⁺Lym in anti-GBM glomerulonephritis. The regulation of CD8⁺Lym by peroxisome proliferator-activated receptor (PPAR)-α in anti-GBM glomerulonephritis was also evaluated. Glomerular infiltrating CD8⁺Lym were lineage-negative cells that showed markedly high expression of IFN-γ and T-bet mRNAs but not Eomes, indicating these cells are group 1 innate lymphoid cells. In anti-GBM glomerulonephritis, the glomerular mRNAs of innate lymphoid cell-related cytokines (IFN-γ and TNF-α) and chemokines (CXCL9, CXCL10, and CXCL11) are significantly increased. Treatment with a PPARα agonist ameliorated renal injury, with reduced expression of these mRNAs. In vitro, enhanced IFN-γ production from innate lymphoid cells upon IL-12 and IL-18 stimulation was reduced by the PPARα agonist. Moreover, CXCL9 mRNA in glomerular endothelial cells and CXCL9, CXCL10, and CXCL11 mRNAs in podocytes and macrophages were upregulated by IFN-γ, whereas the PPARα agonist downregulated their expression. We also detected the infiltration of innate lymphoid cells into glomeruli in human anti-GBM glomerulonephritis. Thus, innate lymphoid cells are involved in the progression of anti-GBM glomerulonephritis and regulated directly or indirectly by PPARα. Our findings suggest that innate lymphoid cells could serve as novel therapeutic targets for anti-GBM glomerulonephritis.

Genetic polymorphisms of PPAR genes and human cancers: evidence for gene-environment interactions

Peroxisome proliferator-activated receptors (PPARs) are nuclear transcription factors that play a role in lipid metabolism, cell proliferation, terminal differentiation, apoptosis, and inflammation. Although several cancer models have been suggested to explain PPARs' involvement in tumorigenesis, however, their role is still unclear. In this review, we examined associations of the different PPARs, polymorphisms and various types of cancer with a focus on gene-environment interactions. Reviewed evidence suggests that functional genetic variants of the different PPARs may modulate the relationship between environmental exposure and cancer risk. In addition, this report unveils the scarcity of reliable quantitative environmental exposure data when examining these interactions, and the current gaps in studying gene-environment interactions in many types of cancer, particularly colorectal, prostate, and bladder cancers.

Nanoemulsion strategy of pioglitazone for the treatment of skin inflammatory diseases

Pioglitazone (PGZ) is a peroxisome proliferator-activated receptor agonist. Its role in the inflammatory response modulation paves the way for additional therapeutic applications. The purpose of this study was to develop a pioglitazone nanoemulsion (PGZ-NE) in order to investigate its anti-inflammatory efficacy on the skin. To that end, an NE vehicle developed for skin delivery was optimized and characterized. The resulting PGZ-NE showed good anti-inflammatory efficacy by decreasing the expression of inflammatory cytokines IL-6, IL-1β and TNF-α. The properties of the developed nanocarrier allowed achievement of a high permeation flux of PGZ through the skin as well as a high retained amount in the skin, likely due to the depot effect of ingredients, which assured a prolonged local action, with good skin tolerability among participating individuals. Consequently, these results suggest that PGZ-NE may be used as an alternative treatment for inflammatory skin diseases such as rosacea, atopic dermatitis or psoriasis.

Sumoylation of PPARγ contributes to vascular endothelium insulin resistance through stabilizing the PPARγ-NcoR complex

Sumoylation of peroxisome proliferator-activated receptor γ (PPARγ) affects its stabilization, sublocalization, and transcriptional activity. However, it remains largely unknown whether PPARγ sumoylation inhibits the transactivation effect, leading to endothelium insulin resistance (IR). To test this possibility, human umbilical vascular endothelial cells (HUVECs) with a 90% confluence were randomly allocated to two batches. One batch was first pretreated with or without vitamin E for 24 hr and the other infected with adenoviruses containing either PIAS1-shRNA (protein inhibitor of activated STAT1-short hairpin RNA) or scramble shRNA. Cells were suffered from high glucose and palmitic acid (PA) exposure for further 48 hr. The levels of PPARγ, p-IKK, IKK, and NcoR (nuclear corepressors) were measured by western blot analysis. The interaction of IKK and PIAS1, as well as the PPARγ sumoylation, were examined by coimmunoprecipitation. The results showed that the exposure of high glucose and PA induced reactive oxygen species (ROS) production and IKK activation in HUVECs, promoting the interaction of IKK and PIAS1 and the sumoylation of PPARγ. However, vitamin E and PIAS1-shRNA partially decreased ROS production and IKK activation induced by high glucose and PA exposure. These data indicate that ROS-IKK-PIAS1 pathway mediates PPARγ sumoylation, leading to endothelium IR via stabilizing PPARγ-NcoR complex. These findings benefit understanding of regulatory networks of insulin signaling, which might provide a potential target to prevent and cure IR-related diseases.

Tackling Residual Atherosclerotic Risk in Statin-Treated Adults: Focus on Emerging Drugs

Epidemiological studies and meta-analyses have consistently suggested the importance of lowering low-density lipoprotein cholesterol (LDL-C) to reduce cardiovascular (CV) events. However, these studies and mechanistic studies using intracoronary imaging modalities have reported patients who continue to experience CV events or disease progression despite optimal LDL-C levels on statins. These findings, including statin intolerance, have highlighted the importance of exploring additional potential therapeutic targets to reduce CV risk. Genomic insights have presented a number of additional novel targets in lipid metabolism. In particular, proprotein convertase subtilisin/kexin type 9 inhibitors have rapidly developed and recently demonstrated their beneficial impact on CV outcomes. Triglyceride (TG)-rich lipoproteins have been recently reported as a causal factor of atherosclerotic cardiovascular disease (ASCVD). Indeed, several promising TG-targeting therapies are being tested at various clinical stages. In this review, we present the evidence to support targeting atherogenic lipoproteins to target residual ASCVD risk in statin-treated patients.

Periostin and CCN2 Scaffolds Promote the Wound Healing Response in the Skin of Diabetic Mice

IMPACT STATEMENT

Nonhealing skin wounds remain a significant burden on health care systems, with diabetic patients 20 times as likely to undergo a lower extremity amputation due to impaired healing. Novel treatments that suppress the proinflammatory signature and induce the proliferative and remodeling phases are needed clinically. We demonstrate that the addition of periostin and CCN2 in a scaffold form increases closure rates of full-thickness skin wounds in diabetic mice, concomitant with enhanced angiogenesis. Our results demonstrate the efficacy of periostin- and CCN2-containing biomaterials to stimulate wound closure, which could represent a novel method for the treatment of diabetic skin wounds.

Peroxisome proliferator-activated receptor gamma and BRCA1

Peroxisome proliferator-activated receptor gamma agonists have been proposed as breast cancer preventives. Individuals who carry a mutated copy of BRCA1, DNA repair-associated gene, are at increased risk for development of breast cancer. Published data in the field suggest there could be interactions between peroxisome proliferator-activated receptor gamma and BRCA1 that could influence the activity of peroxisome proliferator-activated receptor gamma agonists for prevention. This review explores these possible interactions between peroxisome proliferator-activated receptor gamma, peroxisome proliferator-activated receptor gamma agonists and BRCA1 and discusses feasible experimental directions to provide more definitive information on the potential connections.

Acute treatment with Mangifera indica L. leaf extract attenuates liver inflammation in rats fed a cafeteria diet

This study investigates the acute anti-inflammatory activity of Mangifera indica L. leaf extract and mangiferin in the liver of rats fed a cafeteria diet.