The pleiotropic functions of peroxisome proliferator-activated receptor gamma

The Intervention of Probiotics on Type 2 Diabetes Mellitus in Animal Models

Type 2 diabetes accounts for more than 90% of diabetes patients with the incidence and prevalence continuously rising globally. As a prospective therapy strategy for type 2 diabetes, probiotics have shown beneficial effects both in animal experiments and human clinical trials. This review summarizes the commonly used animal models in probiotic intervention research and presents the evidence and mechanism of diabetes intervention with probiotics in these animal models. Probiotics can help maintain glucose homeostasis, improve lipid metabolism, promote the production of short-chain fatty acids, and reduce inflammatory reactions in animal models. However, the clinical translation of benefits from probiotics is still challenged by intrinsic differences between experimental animal models and humans, and the application of humanized non-rodent diabetic animal models may contribute to the clinical translation of probiotics in the future.

Thiazolidinedione as a Promising Medicinal Scaffold for the Treatment of Type 2 Diabetes

BACKGROUND

Thiazolidinediones, also known as glitazones, are considered as biologically active scaffold and a well-established class of anti-diabetic agents for the treatment of type 2 diabetes mellitus. Thiazolidinediones act by reducing insulin resistance through elevated peripheral glucose disposal and glucose production. These molecules activate peroxisome proliferated activated receptor (PPARγ), one of the sub-types of PPARs, and a diverse group of its hybrid have also shown numerous therapeutic activities along with antidiabetic activity.

OBJECTIVE

The objective of this review was to collect and summarize the research related to the medicinal potential, structure-activity relationship and safety aspects of thiazolidinedione analogues designed and investigated in type 2 diabetes during the last two decades.

METHODS

The mentioned objective was achieved by collecting and reviewing the research manuscripts, review articles, and patents from PubMed, Science Direct, Embase, google scholar and journals related to the topic from different publishers like Wiley, Springer, Elsevier, Taylor and Francis, Indian and International government patent sites etc. Results: The thiazolidinedione scaffold has been a focus of research in the design and synthesis of novel derivatives for the management of type 2 diabetes, specifically in the case of insulin resistance. The complications like fluid retention, idiosyncratic hepatotoxicity, weight gain and congestive heart failure in the case of trosiglitazone, and pioglitazone have restricted their use. The newer analogues have been synthesized by different research groups to attain better efficacy and less side effects.

CONCLUSION

Thus, the potential of thiazolidinediones in terms of their chemical evolution, action on nuclear receptors, aldose reductase and free fatty acid receptor 1 is well established. The newer TZD analogues with better safety profiles and tolerability will soon be available in the market for common use without further delay.

Intestinal Immune Imbalance is an Alarm in the Development of IBD

Immune regulation plays a crucial role in human health and disease. Inflammatory bowel disease (IBD) is a chronic relapse bowel disease with an increasing incidence worldwide. Clinical treatments for IBD are limited and inefficient. However, the pathogenesis of immune-mediated IBD remains unclear. This review describes the activation of innate and adaptive immune functions by intestinal immune cells to regulate intestinal immune balance and maintain intestinal mucosal integrity. Changes in susceptible genes, autophagy, energy metabolism, and other factors interact in a complex manner with the immune system, eventually leading to intestinal immune imbalance and the onset of IBD. These events indicate that intestinal immune imbalance is an alarm for IBD development, further opening new possibilities for the unprecedented development of immunotherapy for IBD.

Correlation between PPARG Pro12Ala Polymorphism and Therapeutic Responses to Thiazolidinediones in Patients with Type 2 Diabetes: A Meta-Analysis

Background: Thiazolidinediones (TZDs) are a type of oral drug that are utilized for the treatment of type 2 diabetes mellitus (T2DM). They function by acting as agonists for a nuclear transcription factor known as peroxisome proliferator-activated receptor-gamma (PPAR-γ). TZDs, such as pioglitazone and rosiglitazone, help enhance the regulation of metabolism in individuals with T2DM by improving their sensitivity to insulin. Previous studies have suggested a relationship between the therapeutic efficacy of TZDs and the PPARG Pro12Ala polymorphism (C > G, rs1801282). However, the small sample sizes of these studies may limit their applicability in clinical settings. To address this limitation, we conducted a meta-analysis assessing the influence of the PPARG Pro12Ala polymorphism on the responsiveness of TZDs. Method: We registered our study protocol with PROSPERO, number CRD42022354577. We conducted a comprehensive search of the PubMed, Web of Science, and Embase databases, including studies published up to August 2022. We examined studies investigating the association between the PPARG Pro12Ala polymorphism and metabolic parameters such as hemoglobin A_1C (HbA_1C), fasting plasma glucose (FPG), triglyceride (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and total cholesterol (TC). The mean difference (MD) and 95% confidence intervals (CIs) between pre- and post-drug administration were evaluated. The quality of the studies included in the meta-analysis was assessed by using the Newcastle-Ottawa Scale (NOS) tool for cohort studies. Heterogeneity across studies was assessed by using the I² value. An I² value greater than 50% indicated substantial heterogeneity, and a random-effects model was used for meta-analysis. If the I² value was below 50%, a fixed-effects model was employed instead. Both Begg's rank correlation test and Egger's regression test were performed to detect publication bias, using R Studio software. Results: Our meta-analysis incorporated 6 studies with 777 patients for blood glucose levels and 5 studies with 747 patients for lipid levels. The included studies were published between 2003 and 2016, with the majority involving Asian populations. Five of the six studies utilized pioglitazone, while the remaining study employed rosiglitazone. The quality scores, as assessed with the NOS, ranged from 8 to 9. Patients carrying the G allele exhibited a significantly greater reduction in HbA_1C (MD = -0.3; 95% CI = -0.55 to -0.05; p = 0.02) and FPG (MD = -10.91; 95% CI = -19.82 to -2.01; p = 0.02) levels compared to those with the CC genotype. Furthermore, individuals with the G allele experienced a significantly larger decrease in TG levels than those with the CC genotype (MD = -26.88; 95% CI = -41.30 to -12.46; p = 0.0003). No statistically significant differences were observed in LDL (MD = 6.69; 95% CI = -0.90 to 14.29; p = 0.08), HDL (MD = 0.31; 95% CI = -1.62 to 2.23; p = 0.75), and TC (MD = 6.4; 95% CI = -0.05 to 12.84; p = 0.05) levels. No evidence of publication bias was detected based on Begg's test and Egger's test results. Conclusions: This meta-analysis reveals that patients with the Ala12 variant in the PPARG Pro12Ala polymorphism are more likely to exhibit positive responses to TZD treatment in terms of HbA_1C, FPG, and TG levels compared to those with the Pro12/Pro12 genotype. These findings suggest that genotyping the PPARG Pro12Ala in diabetic patients may be advantageous for devising personalized treatment strategies, particularly for identifying individuals who are likely to respond favorably to TZDs.

Fructose-mediated NLRP3 activation induces inflammation and lipogenesis in adipose tissue

Adipose tissue plays a crucial role in energy intake and regulation of metabolic homeostasis. Fructose consumption implicates in development and progression of metabolic dysfunctions. Fructose is a lipogenic sugar known to induce inflammatory response. However, the role of specific inflammatory signal such as nucleotide-binding and oligomerization domain-like receptor, leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) in fructose-induced inflammatory response and its relevance to lipogenesis in adipose tissue are elusive. We assessed NLRP3 activation and its significance in inflammatory response and lipogenesis in epididymal adipose tissue of 60% fructose diet (HFrD)-fed rats. The long term consumption of HFrD led to impairment of glucose metabolism, development of visceral adiposity, insulin resistance, and elevation of serum triglycerides level, accompanied by activation of NLRP3 in adipose tissue. NLRP3 inflammasome activation in adipose tissue was associated with up-regulated expression of Nlrp3, Asc, and Caspase-1, and raised caspase-1 activity, which resulted in increased expression of IL-1β and IL-18 and secretion of IL-1β. Moreover, lipid accumulation and expression of transcription factors exacerbating accumulation of lipids were augmented in adipose tissue of HFrD-fed rats. Treatment with glyburide, quercetin or allopurinol corrected HFrD-induced dyslipidemia or hyperuricemia, and blocked NLRP3 activation, leading to mitigated inflammatory signalling and lipid accumulation in adipose tissue, improved glucose tolerance and insulin sensitivity in HFrD-fed rats. These data suggest the role of NLRP3 inflammasome to establish linkage among inflammation, lipid accumulation and insulin resistance in adipose tissue, and targeting NLRP3 inflammasome may be a plausible approach for prevention and management for fructose-induced metabolic impairments.

PPARγ Regulates Triclosan Induced Placental Dysfunction

Exposure to the antibacterial agent triclosan (TCS) is associated with abnormal placenta growth and fetal development during pregnancy. Peroxisome proliferator-activated receptor γ (PPARγ) is crucial in placenta development. However, the mechanism of PPARγ in placenta injury induced by TCS remains unknown. Herein, we demonstrated that PPARγ worked as a protector against TCS-induced toxicity. TCS inhibited cell viability, migration, and angiogenesis dose-dependently in HTR-8/SVneo and JEG-3 cells. Furthermore, TCS downregulated expression of PPARγ and its downstream viability, migration, angiogenesis-related genes HMOX1, ANGPTL4, VEGFA, MMP-2, MMP-9, and upregulated inflammatory genes p65, IL-6, IL-1β, and TNF-α in vitro and in vivo. Further investigation showed that overexpression or activation (rosiglitazone) alleviated cell viability, migration, angiogenesis inhibition, and inflammatory response caused by TCS, while knockdown or inhibition (GW9662) of PPARγ had the opposite effect. Moreover, TCS caused placenta dysfunction characterized by the significant decrease in weight and size of the placenta and fetus, while PPARγ agonist rosiglitazone alleviated this damage in mice. Taken together, our results illustrated that TCS-induced placenta dysfunction, which was mediated by the PPARγ pathway. Our findings reveal that activation of PPARγ might be a promising strategy against the adverse effects of TCS exposure on the placenta and fetus.

Dietary copper supplementation enhances lipolysis in Rex rabbits

BACKGROUND

Copper is an important regulator of lipid metabolism in mammals, as a cofactor of many enzymes and is involved in the lipolysis. Copper deficiency has been considered as a significant factor in human diseases related to abnormal lipid metabolism, while adding copper to the diet seems to be the simplest and most effective way to prevent copper deficiency.

AIMS

The aim of this study was to investigate the effects of dietary copper level on lipid metabolism in Rex Rabbits.

METHODS

A total of 120 90-d-old Rex Rabbits were randomly allotted into three treatments, with 40 replicates (20 males, 20 females) in each treatment (1 rabbit per replicate). The diets included 1) control (8.4 mg/kg), normal-copper diet (39.1 mg/kg), 3) high-copper diet (67.5 mg/kg). The trial including a one-week adaptation period and a five-week experimental period.

RESULT

The results showed that copper (39.1 mg/kg) diet increased average daily feed intake (ADFI) (P＜0.05, N = 34), and tended to increase the final body weight (FBW) (P = 0.0556, N = 34). Moreover, dietary copper addition (39.1 and 67.5 mg/kg) significantly increased the foreleg and hindleg weight (P＜0.05, N = 8), and decreased the weight of Perirenal fat and the concentration of triglycerides (TG) in the liver (P＜0.05, N = 8). The concentration of triglycerides (TG), epinephrine (EPI), and glucagon (GC) in serum were obviously higher than that in control group (P＜0.05, N = 8), and the concentration of insulin (INS), and very low-density lipoprotein (VLDL) in serum were significantly decreased (P＜0.05, N = 8). The copper group (39.1 mg/kg) showed up-regulated gene expression levels of carnitine palmitoyl transferases (CPT-1 and CPT-2) and peroxisome proliferator-activated receptor (PPAR-α) in liver (P < 0.05, N = 8) and down-regulated gene expression levels of fatty acid synthase (FAS) and Acetyl-CoA carboxylase (ACC) (P < 0.05, N = 8). In skeletal muscle, CPT-1, CPT-2, PPAR-α, fatty acid transport protein (FATP), fatty acid-binding protein (FABP) and lipoprotein lipase (LPL) levels were significantly up-regulated by copper treatment (P < 0.05, N = 8). Rex Rabbits receiving copper addition had higher CPT-1, CPT-2, PPAR-a and hormone-sensitive lipase (HSL) mRNA levels in adipose tissue (P < 0.05, N = 8).

CONCLUSION

Copper diets promoted skeletal muscle growth and reduced fat accumulation by enhancing fatty acid oxidation, at the same time, dietary copper inhibited De novo lipogenesis in the liver. PPAR-α signaling in liver, skeletal muscle and adipose tissues were involved in the regulation of lipid metabolism by copper.

Monascin and Ankaflavin of Monascus purpureus Prevent Alcoholic Liver Disease through Regulating AMPK-Mediated Lipid Metabolism and Enhancing Both Anti-Inflammatory and Anti-Oxidative Systems

Alcohol metabolism causes an excessive accumulation of liver lipids and inflammation, resulting in liver damage. The yellow pigments monascin (MS) and ankaflavin (AK) of Monascus purpureus-fermented rice were proven to regulate ethanol-induced damage in HepG2 cells, but the complete anti-inflammatory and anti-fatty liver mechanisms in the animal model are still unclear. This study explored the roles of MS and AK in improving alcoholic liver injury. MS and AK were simultaneously fed to evaluate their effects and mechanisms in C57BL/6J mice fed the Lieber–DeCarli liquid alcohol diet for 6 weeks. The results indicated that MS and AK significantly reduced the serum aspartate aminotransferase and alanine aminotransferase activity, as well as the total liver cholesterol and triglyceride levels. The histopathological results indicated that MS and AK prevented lipid accumulation in the liver. MS and AK effectively enhanced the activity of antioxidant enzymes and reduced the degree of lipid peroxidation; AK was particularly effective and exhibited a superior preventive effect against alcoholic liver injury and fatty liver. In addition to inhibiting the phosphorylation of the MAPK family, MS and AK directly reduced TNF-α, IL-6, and IL-1β levels, thereby reducing NF-κB and its downstream iNOS and COX-2 expressions, as well as increasing PPAR-γ, Nrf-2, and HO-1 expressions to prevent liver damage. MS and AK also directly reduced TNF-α, IL-6, and IL-1β expression, thereby reducing the production of NF-κB and its downstream iNOS and COX-2, and increasing PPAR-γ, Nrf-2, and HO-1 expressions, preventing alcohol damage to the liver.

Beneficial Effect of Taraxacum coreanum Nakai via the Activation of LKB1-AMPK Signaling Pathway on Obesity

Objective

Liver kinase B (LKB) 1 and AMP-activated protein kinase (AMPK) are master regulators and sensors for energy homeostasis. AMPK is mainly activated via phosphorylation of LKB1 under energy stress. Here, we highlighted the antiobesity effect and underlying mechanism of Taraxacum coreanum Nakai (TCN) in connection with LKB1-AMPK signaling pathway.

Methods

Male C57BL/6 mice were fed on a high-fat diet (60% kcal fat; HFD) to induce obesity. Simultaneously, they received 100 or 200 mg/kg TCN orally for 5 weeks. We measured the body weight gain and liver weight along with liver histology. Moreover, the changes of factors related to lipid metabolism and β-oxidation were analyzed in the liver, together with blood parameters.

Results

The body weights were decreased in mice of the TCN200 group more than those of the HFD control group. Moreover, TCN supplementation lowered serum triglyceride (TG) and total cholesterol (TC) levels, whereas TCN increased HDL-cholesterol level. Liver pathological damage induced by HFD was alleviated with TCN treatment and accompanied with significant reduction in serum AST and ALT activities. In addition, TCN significantly increased the expression of p-AMPK compared with the HFD control group via the activation of LKB1/AMPK signaling pathway. Lipid synthesis gene like ACC was downregulated and factors related to β-oxidation such as carnitine palmitoyl transferase-1 (CPT-1) and uncoupling protein 2 (UCP-2) were upregulated through peroxisome proliferator-activated receptor (PPAR) α activation.

Conclusion

Taken together, these data suggest that TCN treatment regulates lipid metabolism via LKB1-AMPK signaling pathway and promotes β-oxidation by PPARα; hence, TCN may have potential remedy in the prevention and treatment of obesity.

MHY2013 Modulates Age-related Inflammation and Insulin Resistance by Suppressing the Akt/FOXO1/IL-1β Axis and MAPK-mediated NF-κB Signaling in Aged Rat Liver

Chronic inflammation is a major risk factor underlying aging and age-associated diseases. It impairs normal lipid accumulation, adipose tissue function, and mitochondrial function, which eventually lead to insulin resistance. Peroxisome proliferator-activated receptors (PPARs) critically regulate gluconeogenesis, lipid metabolism, and the lipid absorption and breakdown process, and PPAR activity decreases in the liver during aging. In the present study, we investigated the ability of 2-(4-(5,6-methylenedioxybenzo[d]thiazol-2-yl)-2-methylphenoxy)-2-methylpropanoic acid (MHY2013), synthesized PPARα/PPARβ/PPARγ pan agonist, to suppress the inflammatory response and attenuate insulin resistance in aged rat liver. Six- and 20-month-old rats were divided into 4 groups: young and old rats fed ad libitum; and old rats fed ad libitum supplemented with MHY2013 (1 mg and 5 mg/kg/d for 4 wk). We found that MHY2013 supplementation efficiently downregulated the activity of nuclear factor-κB through JNK/ERK/p38 mitogen-activated protein kinase signaling in the liver of aged rats. In addition, MHY2013 treatment increased hepatic insulin signaling, and the downstream signaling activity of FOXO1, which is negatively regulated by Akt. Downregulation of Akt increases expression of FOXO1, which acts as a transcription factor and increases transcription of interleukin-1β, leading to hepatic inflammation. The major finding of this study is that MHY2013 acts as a therapeutic agent against age-related inflammation associated with insulin resistance by activating PPARα, PPARβ, and PPARγ. Thus, the study provides evidence for the anti-inflammatory properties of MHY2013, and the role it plays in the regulation of age-related alterations in signal transduction pathways.

Minutes of PPAR-γ agonism and neuroprotection

Peroxisome proliferator-activated receptor gamma (PPAR-γ) is one of the ligand-activated transcription factors which regulates a number of central events and considered as a promising target for various neurodegenerative disease conditions. Numerous reports implicate that PPAR-γ agonists have shown neuroprotective effects by regulating genes transcription associated with the pathogenesis of neurodegeneration. In regards, this review critically appraises the recent knowledge of PPAR-γ receptors in neuroprotection in order to hypothesize potential neuroprotective mechanism of PPAR-γ agonism in chronic neurological conditions. Of note, the PPAR-γ's interaction dynamics with PPAR-γ coactivator-1α (PGC-1α) has gained significant attention for neuroprotection. Likewise, a plethora of studies suggest that the PPAR-γ pathway can be actuated by the endogenous ligands present in the CNS and thus identification and development of novel agonist for the PPAR-γ receptor holds a vow to prevent neurodegeneration. Together, the critical insights of this review enlighten the translational possibilities of developing novel neuroprotective therapeutics targeting PPAR-γ for various neurodegenerative disease conditions.

Targeting of cellular redox metabolism for mitigation of radiation injury

Accidental exposure to ionizing radiation is a serious concern to human life. Studies on the mitigation of side effects following exposure to accidental radiation events are ongoing. Recent studies have shown that radiation can activate several signaling pathways, leading to changes in the metabolism of free radicals including reactive oxygen species (ROS) and nitric oxide (NO). Cellular and molecular mechanisms show that radiation can cause disruption of normal reduction/oxidation (redox) system. Mitochondria malfunction following exposure to radiation and mutations in mitochondria DNA (mtDNA) have a key role in chronic oxidative stress. Furthermore, exposure to radiation leads to infiltration of inflammatory cells such as macrophages, lymphocytes and mast cells, which are important sources of ROS and NO. These cells generate free radicals via upregulation of some pro-oxidant enzymes such as NADPH oxidases, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Epigenetic changes also have a key role in a similar way. Other mediators such as mammalian target of rapamycin (mTOR) and peroxisome proliferator-activated receptor (PPAR), which are involved in the normal metabolism of cells have also been shown to regulate cell death following exposure to radiation. These mechanisms are tissue specific. Inhibition or activation of each of these targets can be suggested for mitigation of radiation injury in a specific tissue. In the current paper, we review the cellular and molecular changes in the metabolism of cells and ROS/NO following exposure to radiation. Furthermore, the possible strategies for mitigation of radiation injury through modulation of cellular metabolism in irradiated organs will be discussed.

Dysfunction of inflammatory pathways in adolescent female patients with anorexia nervosa

BACKGROUND

The pathogenesis of Eating Disorders is still unknown. However, a growing body of evidence shows that there are changes in cytokine levels and an alteration in the stress response in patients with anorexia nervosa (AN). For this reason, we decided to test whether there are differences in immune parameters involved in the regulation of the inflammatory response between female adolescents with AN and healthy adolescents.

METHODS

The sample 27 drug-naïve AN patients the study sample included 27 AN patients at a very early stage of the disease and 23 healthy controls. Plasma and peripheral blood mononuclear cells (PBMCs) were obtained for biochemical study.

RESULTS

Plasma levels of the pro-inflammatory cytokines TNF-α and IL-1β were significantly increased in patients with AN, while the levels of prostaglandins PGE₂ (proinflammatory) and 15d-PGJ₂, (anti-inflammatory) were lower compared with controls. Protein expression in PBMCs of cyclooxygenase-2 (COX-2) and the activated forms of the mitogen-activated protein kinases p38 and ERK were also increased in the AN group. Expression levels of the anti-inflammatory factor peroxisome proliferator-activated receptor gamma (PPARγ) were significantly decreased in patients. Plasma levels of lipid peroxidation markers -TBARS- were not increased in patients with AN. Components of the biochemical inflammatory response (COX-2, PGE₂, TBARS, 15d-PGJ₂, ERK, p65 NFκB) and glucocorticoid receptor -GR- expression and the scores on the impulsivity measures in the BARRATT, EDI and BITE questionnaires showed a significant correlation within the AN patients group.

CONCLUSIONS

The results for female adolescent patients with AN indicate that there is a dysfunction of intra- and intercellular inflammatory pathways characterized by higher levels of pro-inflammatory parameters in plasma and a decrease in one of the controlling cytoplasmic-nuclear pathways implicated in their modulation (i.e. PPARγ) with, at this very early stage of the disease, no effect on oxidative stress markers plasma levels. Most notably, higher severity of illness (restrictive and purging behaviour) correlated with higher levels of inflammatory markers.

Ginsenoside Rb1 ameliorates CKD-associated vascular calcification by inhibiting the Wnt/β-catenin pathway

Vascular calcification (VC) is a pathological process underpinning major cardiovascular conditions and has attracted public attention due to its high morbidity and mortality. Chronic kidney disease (CKD) is a common disease related to VC. Ginsenoside Rb1 (Rb1) has been reported to protect the cardiovascular system against vascular diseases, yet its role in VC and the underlying mechanisms remain unclear. In this study, we established a CKD‐associated VC rat model and a β‐glycerophosphate (β‐GP)‐induced vascular smooth muscle cell (VSMC) calcification model to investigate the effects of Rb1 on VC. Our results demonstrated that Rb1 ameliorated calcium deposition and VSMC osteogenic transdifferentiation both in vivo and in vitro. Rb1 treatment inhibited the Wnt/β‐catenin pathway by activating peroxisome proliferator‐activated receptor‐γ (PPAR‐γ), and confocal microscopy was used to show that Rb1 inhibited β‐catenin nuclear translocation in VSMCs. Furthermore, SKL2001, an agonist of the Wnt/β‐catenin pathway, compromised the vascular protective effect of Rb1. GW9662, a PPAR‐γ antagonist, reversed Rb1's inhibitory effect on β‐catenin. These results indicate that Rb1 exerted anticalcific properties through PPAR‐γ/Wnt/β‐catenin axis, which provides new insights into the potential theraputics of VC.

Annexins in Adipose Tissue: Novel Players in Obesity

Obesity and the associated comorbidities are a growing health threat worldwide. Adipose tissue dysfunction, impaired adipokine activity, and inflammation are central to metabolic diseases related to obesity. In particular, the excess storage of lipids in adipose tissues disturbs cellular homeostasis. Amongst others, organelle function and cell signaling, often related to the altered composition of specialized membrane microdomains (lipid rafts), are affected. Within this context, the conserved family of annexins are well known to associate with membranes in a calcium (Ca²⁺)- and phospholipid-dependent manner in order to regulate membrane-related events, such as trafficking in endo- and exocytosis and membrane microdomain organization. These multiple activities of annexins are facilitated through their diverse interactions with a plethora of lipids and proteins, often in different cellular locations and with consequences for the activity of receptors, transporters, metabolic enzymes, and signaling complexes. While increasing evidence points at the function of annexins in lipid homeostasis and cell metabolism in various cells and organs, their role in adipose tissue, obesity and related metabolic diseases is still not well understood. Annexin A1 (AnxA1) is a potent pro-resolving mediator affecting the regulation of body weight and metabolic health. Relevant for glucose metabolism and fatty acid uptake in adipose tissue, several studies suggest AnxA2 to contribute to coordinate glucose transporter type 4 (GLUT4) translocation and to associate with the fatty acid transporter CD36. On the other hand, AnxA6 has been linked to the control of adipocyte lipolysis and adiponectin release. In addition, several other annexins are expressed in fat tissues, yet their roles in adipocytes are less well examined. The current review article summarizes studies on the expression of annexins in adipocytes and in obesity. Research efforts investigating the potential role of annexins in fat tissue relevant to health and metabolic disease are discussed.

Cannabinoids in Gynecological Diseases

The endocannabinoid system (ECS) is a multifunctional homeostatic system involved in many physiological and pathological conditions. The ligands of the ECS are the endo-cannabinoids, whose actions are mimicked by exogenous cannabinoids, such as phytocannabinoids and synthetic cannabinoids. Responses to the ligands of the ECS are mediated by numerous receptors like the classical cannabinoid receptors (CB₁ and CB₂) as well as ECS-related receptors, e.g., G protein-coupled receptors 18 and 55 (GPR18 and GPR55), transient receptor potential ion channels, and nuclear peroxisome proliferator-activated receptors. The ECS regulates almost all levels of female reproduction, starting with oocyte production through to parturition. Dysregulation of the ECS is associated with the development of gynecological disorders from fertility disorders to cancer. Cannabinoids that act at the ECS as specific agonists or antagonists may potentially influence dysregulation and, therefore, represent new therapeutic options for the therapy of gynecological disorders.

Bisphenol S-induced chronic inflammatory stress in liver via peroxisome proliferator-activated receptor γ using fish in vivo and in vitro models

Bisphenol S (BPS) has been widely used as a bisphenol alternative in recent few years. However, with mounting evidence suggesting that the presence of BPS in the environment also poses risks to ecosystems and human health, we decided to use the juvenile common carp (Cyprinus carpio) and its primary macrophages as in vivo and in vitro models to examine if BPS is a safe substitute of BPA. The present study evaluated the immune responses of chronic BPS exposure and their mechanisms of action associated with peroxisome proliferator-activated receptor (PPAR) signaling pathway. Potential oxidative stress and pro-inflammatory effects of BPS exposure were identified in fish liver after 60-day exposure, based on the increased reactive oxygen species (ROS) production, antioxidant capacity, NO production, lipid peroxidation, and induction of inflammatory cytokine expression, as well as acute phase protein levels of C-reactive protein, immunoglobulin M, lysozyme, and complement component 3. Moreover, pparγ, PPAR pathway-associated genes retinoid x receptor α (rxrα) and nuclear factor-κb (nfκb) presented a rough concentration-dependent alteration after BPS exposure. An acute BPS exposure to the isolated primary macrophages from juvenile common carp was performed to help elucidate gene expression patterns of pparγ, rxrα, and nfκb in a typical immune cell model, the results were consistent with what we found in vivo experiments for long-term BPS exposure. Furthermore, with coexposure to BPS and a PPARγ antagonist, the restriction of PPAR signaling pathway significantly inhibited the induction of ROS and the mRNA level of interleukin-1β, confirming the involvement of PPAR pathway in BPS-induced chronic inflammatory stress in liver.

Effect of pomegranate seed oil on the expression of PPAR-γ and pro-inflammatory biomarkers in obese type 2 diabetic patients

Purpose

Diabetes is one of the most prevailed chronic diseases in the world. Pro-inflammatory cytokines play a key role in the type 2 diabetes mellitus. Pomegranate seed oil (PSO) has potential anti-inflammatory properties. The purpose of this study is to evaluate the antidiabetic effects of the use of PSO on the expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ), pro-inflammatory biomarkers and lipid profile levels in obese type 2 diabetic patients.

Design/methodology/approach

In total, 52 patients were randomly assigned to the PSO (n = 26) and placebo (n = 26) groups. Subjects received daily PSO 3 g placebo (paraffin) in 1 g soft-gel capsules (along with breakfast, lunch and dinner meals) for eight weeks.

Findings

Serum levels of fasting blood sugar (FBS) decreased from 161.46 ± 34.44 to 143.50 ± 24.2 mg/dL (p = 0.008), IL-6 decreased from 5.17 ± 2.25 to 4.52 ± 1.90 (p = 0.049) and tumor necrosis factor alpha (TNF-α) significantly decreased from 9.17 ± 4.13 to 7.74 ± 2.44 pmol/mL in PSO group (p = 0.030). However, changes in the expression of PPAR-γ gene, serum levels of hs-CRP and lipid profile levels were not significant.

Research limitations/implications

Lack of PSO concentration measurements and the short duration of the study were the key limitations. Future randomized clinical trials with a longer period of follow-up are needed to assess the potential anti-diabetic effects of PSO.

Originality/value

Administration of PSO in obese type 2 diabetic patients reduced the levels of FBS, interleukin 6 and TNF-α; nevertheless, changes in the insulin, lipid profiles and hs-CRP were not significant.

Identification of pleiotropic genetic variants affecting osteoporosis risk in a Korean elderly cohort

Pleiotropy has important implications for understanding the genetic basis and risk assessment of osteoporosis. Our aim was to identify pleiotropic genetic variants associated with the development of osteoporosis and predict osteoporosis risk by leveraging pleiotropic variants. We evaluated the effects of 21 conventional risk factors and 185 single-nucleotide polymorphisms (SNPs) in 63 inflammation- and metabolism-related genes on osteoporosis risk in a community-based Korean cohort study of 1025 participants, the Hallym Aging Study. Ten nongenetic factors, including sex (female) and hematocrit level, and 12 SNPs across ten genes showed evidence of association with incident osteoporosis in 270 initially osteoporosis-free subjects who completed a 6-year follow up. Three gene variants, rs1801282 (PPARG-Pro12Ala, hazard ratio (HR) = 3.26, P = 0.008), rs1408282 (near EPHA7, HR = 1.87, P = 0.002), and rs2076212 (PNPLA3-Gly115Cys, HR = 2.24, P = 0.024), were associated with significant differences in survival among the three genotype groups (P_diff = 0.042, 0.003, and 0.048, respectively). Individuals in the highest polygenic risk score tertile were 27.9 fold more likely to develop osteoporosis than those in the lowest tertile (P = 0.004). The PPARG gene in particular was a hub pleiotropic gene in the epistasis network. Our findings highlight pleiotropic modulations of metabolism- and inflammation-related genes in the development of osteoporosis and demonstrate the contribution of pleiotropic genetic variants in prediction of osteoporosis risk.

Apple peel polyphenols reduce mitochondrial dysfunction in mice with DSS-induced ulcerative colitis

Inflammatory bowel diseases (IBDs) are multifaceted and relapsing immune disorders, which necessitate long-term dependence on powerful drugs. As the use of natural product-based therapies has emerged as a promising intervention, the present study aimed to further characterize dried apple peel powder (DAPP) mechanisms of action and evaluate the preventive and curative effects of DAPP on mitochondrial functions in a murine model. Induction of intestinal inflammation in mice is performed by oral administration of the dextran sodium sulfate (DSS) at 2.5% for 10 days. Doses of DAPP (200 or 400 mg/kg/day) were administered by gavage for 10 days pre- and 1 day after colitis induction simultaneously with DSS treatment for a period of 10 days. The preventive (200 mg/kg/day) and therapeutic (400 mg/kg/day) doses of DAPP limited DSS-induced histological lesions, improved macroscopic parameters and attenuated clinical signs. DAPP at the same conditions reduced massive infiltration of inflammatory cells and concomitantly displayed a robust potential of counteracting inflammation and oxidative stress in DSS mice. Moreover, DAPP partially restored mitochondrial abnormalities related to size, density, redox homeostasis, fatty acid β-oxidation, ATP synthesis, apoptosis and regulatory mitochondrial transcription factors. Our findings demonstrate the preventive and therapeutic impact of DAPP on experimental colitis while underlying the role of mitochondria. They also suggest that this natural DAPP product may represent an interesting candidate for further studies on the prevention/treatment of IBD.

5-aminosalicylic acid improves lipid profile in mice fed a high-fat cholesterol diet through its dual effects on intestinal PPARγ and PPARα

Obesity is associated with a series of metabolic complications, including dyslipidemia and insulin resistance (IR) that lack effective therapies. In recent years, intestinal inflammation has been suggested to contribute to obesity related metabolic syndrome and targeting gut inflammation with 5-ASA improves diet induced IR, however, its role in dyslipidemia is unknown and has never been explored. In the present study, we reported for the first time that administration of 5-ASA for 12 weeks significantly improved lipid profile by repressing plasma triglycerides and free cholesterol levels in mice fed high-fat cholesterol diet (HFC). In addition, liver lipids were significantly reduced by 5-ASA treatment in HFC-fed mice. Mechanistically, anti-inflammatory genes peroxisome proliferator-activated receptor-γ (Pparγ) and M2 marker, such as Mrc1 and Ym1, were remarkably upregulated, while pro-inflammation gene monocyte chemoattractant protein-1 (Mcp-1) were downregulated in small intestine of mice treated by 5-ASA. Further, 5-ASA improved gastrointestinal barrier by increasing the expression of the tight junction marker ZO-1. 5-ASA also enhanced cholesterol translocation by elevating genes expression of Npc1l1 and Abcg5/8. Moreover, mice fed HFC 5-ASA expressed increased Pparα in small intestinal and its target genes function in lipid oxidation and hydrolysis were remarkable elevated. Taken together, we reported a novel role of 5-ASA which may serve as a therapy target intestinal inflammation induced dyslipidemia.

Effect of dietary copper addition on lipid metabolism in rabbits

The present study was conducted to investigate the effect of copper supplementation on lipid metabolism in rabbits. Our study showed dietary copper addition (5-45 mg/kg) increased body mass gain, but decreased fat and liver weights compared with those in the control group (P < 0.05). Copper (45 mg/kg) addition significantly increased the skeletal muscle weight, but inhibited cytoplasmic lipid accumulation in liver, skeletal muscle and adipose tissue (P < 0.05). Compared with the control group, dietary copper addition (45 mg/kg) significantly increased plasma triglyceride levels but decreased very low density lipoprotein levels (P < 0.05). Copper treatment significantly increased gene expression of carnitine palmitoyltransferase (CPT) 1, CPT2 and peroxisome proliferator-activated receptor (PPAR) a in liver (P < 0.05). In skeletal muscle, CPT1, CPT2, fatty acid transport protein, fatty acid-binding protein, and PPARa mRNA as well as phosphorylated AMP-activated protein kinase (AMPK) levels were significantly up-regulated by copper treatment (P < 0.05). Rabbits receiving copper supplementation had higher CPT1, CPT2, PPARa and hormone-sensitive lipase mRNA levels in adipose tissue (P < 0.05). In conclusion, copper promoted skeletal muscle growth and reduced fat accretion. PPARa signaling in liver, skeletal muscle and adipose tissues and AMPK signaling in skeletal muscle tissue were involved in the regulation of lipid metabolism by copper.

Transcriptomic Analyses of Adipocyte Differentiation From Human Mesenchymal Stromal-Cells (MSC)

Adipogenesis is a physiological process required for fat-tissue development, mainly involved in regulating the organism energetic-state. Abnormal distribution-changes and dysfunctions in such tissue are associated to different pathologies. Adipocytes are generated from progenitor cells, via a complex differentiating process not yet well understood. Therefore, we investigated differential mRNA and miRNA expression patterns of human mesenchymal stromal-cells (MSC) induced and not induced to differentiate into adipocytes by next (second)-generation sequencing. A total of 2,866 differentially expressed genes (101 encoding miRNA) were identified, with 705 (46 encoding miRNA) being upregulated in adipogenesis. They were related to different pathways, including PPARG, lipid, carbohydrate and energy metabolism, redox, membrane-organelle biosynthesis, and endocrine system. Downregulated genes were related to extracellular matrix and cell migration, proliferation, and differentiation. Analyses of mRNA-miRNA interaction showed that repressed miRNA-encoding genes can act downregulating PPARG-related genes; mostly the PPARG activator (PPARGC1A). Induced miRNA-encoding genes regulate downregulated genes related to TGFB1. These results shed new light to understand adipose-tissue differentiation and physiology, increasing our knowledge about pathologies like obesity, type-2 diabetes and osteoporosis. J. Cell. Physiol. 232: 771-784, 2017. © 2016 Wiley Periodicals, Inc.

PPARγ mRNA in the adult mouse hypothalamus: distribution and regulation in response to dietary challenges

Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that was originally identified as a regulator of peroxisome proliferation and adipocyte differentiation. Emerging evidence suggests that functional PPARγ signaling also occurs within the hypothalamus. However, the exact distribution and identities of PPARγ-expressing hypothalamic cells remains under debate. The present study systematically mapped PPARγ mRNA expression in the adult mouse brain using in situ hybridization histochemistry. PPARγ mRNA was found to be expressed at high levels outside the hypothalamus including the neocortex, the olfactory bulb, the organ of the vasculosum of the lamina terminalis (VOLT), and the subfornical organ. Within the hypothalamus, PPARγ was present at moderate levels in the suprachiasmatic nucleus (SCh) and the ependymal of the 3rd ventricle. In all examined feeding-related hypothalamic nuclei, PPARγ was expressed at very low levels that were close to the limit of detection. Using qPCR techniques, we demonstrated that PPARγ mRNA expression was upregulated in the SCh in response to fasting. Double in situ hybridization further demonstrated that PPARγ was primarily expressed in neurons rather than glia. Collectively, our observations provide a comprehensive map of PPARγ distribution in the intact adult mouse hypothalamus.

Peroxisome proliferator-activated receptor-γ is downregulated in ulcerative colitis and is involved in experimental colitis-associated neoplasia

The aim of the present study was to evaluate the expression of peroxisome proliferator-activated receptor (PPAR)-γ in inflammatory bowel disease (IBD), and to also identify the association between PPAR-γ and the clinical features of patients with IBD. An azoxymethane (AOM)/dextran sodium sulfate (DSS) animal model of colitis-associated neoplasia was established to investigate the protective effect of 5-aminosalicylic acid (5-ASA) and to explore the changes in the expression of PPAR-γ during this process. A total of 66 specimens of colorectal tissue obtained from biopsy performed on IBD patients and 30 healthy control individuals were immunohistochemically stained for PPAR-γ. An AOM/DSS animal model of colitis-associated neoplasia was then established. Reverse transcription quantitative polymerase chain reaction was conducted and it was found that, compared with the control group and patients with Crohn's disease (CD), the expression of PPAR-γ in the intestinal tissue of patients with ulcerative colitis (UC) was significantly decreased (P=0.027 and 0.046, respectively). The expression of PPAR-γ was found to be negatively associated with the disease activity of UC and was not associated with the severity of disease, site of lesions or CD characteristics. Administration of 5-ASA decreased the colitis and tumor burden of colons. The expression level of PPAR-γ in the intestinal tissue was also increased in the AOM/DSS/5-ASA group compared with AOM/DSS group (P<0.001). PPAR-γ is an important factor in the pathogenesis of UC and colitis-associated cancer. The present study found that 5-ASA significantly alleviates the colitis and tumor burden in a mouse model of AOM/DSS-induced colitis-associated neoplasia, and promotes the expression of PPAR-γ in the intestinal tract.

Role of Peroxisome Proliferator-Activated Receptor γ in Ocular Diseases

Peroxisome proliferator-activated receptor γ (PPAR γ), a member of the nuclear receptor superfamily, is a ligand-activated transcription factor that plays an important role in the control of a variety of physiological processes. The last decade has witnessed an increasing interest for the role played by the agonists of PPAR γ in antiangiogenesis, antifibrosis, anti-inflammation effects and in controlling oxidative stress response in various organs. As the pathologic mechanisms of major blinding diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), keratitis, and optic neuropathy, often involve neoangiogenesis and inflammation- and oxidative stress-mediated cell death, evidences are accumulating on the potential benefits of PPAR γ to improve or prevent these vision threatening eye diseases. In this paper we describe what is known about the role of PPAR γ in the ocular pathophysiological processes and PPAR γ agonists as novel adjuvants in the treatment of eye diseases.

Peroxisome proliferator-activated receptor gamma in the colon: inflammation and innate antimicrobial immunity

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor, originally described in adipose tissue, which controls the expression of a large number of regulatory genes in lipid metabolism and insulin sensitization. Well known by endocrinologists, thiazolidinedionesare classical PPARγ synthetic agonists, which were currently used as insulin-sensitizing agents in the treatment of type 2 diabetes. Although the clinical benefits of thiazolidinediones in treating metabolic disorders have been clearly demonstrated, studies performed in animal models of colitis and in patients with ulcerative colitis have also revealed the key roles of PPARγ activation in the regulation of inflammation and immune response, notably in the colon through epithelial cells.

ω-3 PUFA rich camelina oil by-products improve the systemic metabolism and spleen cell functions in fattening pigs

Camelina oil-cakes results after the extraction of oil from Camelina sativa plant. In this study, camelina oil-cakes were fed to fattening pigs for 33 days and its effect on performance, plasma biochemical analytes, pro-/anti-inflammatory mediators and antioxidant detoxifying defence in spleen was investigated in comparison with sunflower meal. 24 crossbred TOPIG pigs were randomly assigned to one of two experimental dietary treatments containing either 12% sunflower meal (treatment 1-T1), or 12.0% camelina oil-cakes, rich in polyunsaturated fatty acids ω-3 (ω-3 PUFA) (treatment 2-T2). The results showed no effect of T2 diet (camelina cakes) on feed intake, average weight gain or feed efficiency. Consumption of camelina diet resulted in a significant decrease in plasma glucose concentration (18.47%) with a trend towards also a decrease of plasma cholesterol. In spleen, T2 diet modulated cellular immune response by decreasing the protein and gene expression of pro-inflammatory markers, interleukin 1-beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin (IL-8) and cyclooxigenase 2 (COX-2) in comparison with T1 diet. By contrast, T2 diet increased (P<0.05) in spleen the mRNA expression of antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase 1 (GPx1) by 3.43, 2.47 and 1.83 fold change respectively, inducible nitric oxide synthase (iNOS) (4.60 fold), endothelial nitric oxide synthase (eNOS) (3.23 fold) and the total antioxidant level (9.02%) in plasma. Camelina diet increased also peroxisome-proliferator activated receptor gamma (PPAR-γ) mRNA and decreased that of mitogen-activated protein kinase 14 (p38α MAPK) and nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB). At this level of inclusion (12%) camelina oil-cakes appears to be a potentially alternative feed source for pig which preserves a high content of ω-3 PUFA indicating antioxidant properties by the stimulation of detoxifying enzymes expression and the suppression of spleen pro-inflammatory markers.

Pioglitazone: an antidiabetic drug with cardiovascular therapeutic effects

The antidiabetic compound pioglitazone, an activator of the intracellular peroxisome proliferator-activated receptor-gamma, and decreases metabolic and vascular insulin resistance. The drug is well tolerated, and its metabolic effects include improvements in blood glucose and lipid control. Vascular effects consist of improvements in endothelial function and hypertension, and a reduction in surrogate markers of artherosclerosis. In a large, placebo-controlled, outcome study in secondary prevention, PROactive study, the use of pioglitazone in addition to an existing optimized macrovascular risk management resulted in a significant reduction of macrovascular endpoints within a short observation period that was comparable to the effect of statins and angiotensin converting enzyme inhibitors in other trials. These results underline the value of pioglitazone for managing the increased cardiovascular risk of patients with a metabolic syndrome or Type 2 diabetes mellitus.

A small volatile bacterial molecule triggers mitochondrial dysfunction in murine skeletal muscle

Mitochondria integrate distinct signals that reflect specific threats to the host, including infection, tissue damage, and metabolic dysfunction; and play a key role in insulin resistance. We have found that the Pseudomonas aeruginosa quorum sensing infochemical, 2-amino acetophenone (2-AA), produced during acute and chronic infection in human tissues, including in the lungs of cystic fibrosis (CF) patients, acts as an interkingdom immunomodulatory signal that facilitates pathogen persistence, and host tolerance to infection. Transcriptome results have led to the hypothesis that 2-AA causes further harm to the host by triggering mitochondrial dysfunction in skeletal muscle. As normal skeletal muscle function is essential to survival, and is compromised in many chronic illnesses, including infections and CF-associated muscle wasting, we here determine the global effects of 2-AA on skeletal muscle using high-resolution magic-angle-spinning (HRMAS), proton (¹H) nuclear magnetic resonance (NMR) metabolomics, in vivo³¹P NMR, whole-genome expression analysis and functional studies. Our results show that 2-AA when injected into mice, induced a biological signature of insulin resistance as determined by ¹H NMR analysis-, and dramatically altered insulin signaling, glucose transport, and mitochondrial function. Genes including Glut4, IRS1, PPAR-γ, PGC1 and Sirt1 were downregulated, whereas uncoupling protein UCP3 was up-regulated, in accordance with mitochondrial dysfunction. Although 2-AA did not alter high-energy phosphates or pH by in vivo³¹P NMR analysis, it significantly reduced the rate of ATP synthesis. This affect was corroborated by results demonstrating down-regulation of the expression of genes involved in energy production and muscle function, and was further validated by muscle function studies. Together, these results further demonstrate that 2-AA, acts as a mediator of interkingdom modulation, and likely effects insulin resistance associated with a molecular signature of mitochondrial dysfunction in skeletal muscle. Reduced energy production and mitochondrial dysfunctional may further favor infection, and be an important step in the establishment of chronic and persistent infections.

SERPINA3K induces apoptosis in human colorectal cancer cells via activating the Fas/FasL/caspase-8 signaling pathway

SERPINA3K, also known as kallikrein-binding protein (KBP), is a serine proteinase inhibitor with anti-inflammatory and anti-angiogenic activities. Our previous studies showed that SERPINA3K inhibited proliferation in a dose-dependent manner and induced apoptosis of endothelial cells but had no influence on SGC-7901 gastric carcinoma cells or HepG2 hepatocarcinoma cells. However, it is unknown whether SERPINA3K has a direct impact on other carcinoma cells and which mechanisms are involved. In this study, we report for the first time that SERPINA3K not only decreased cell viability but also induced apoptosis in the colorectal carcinoma cell lines SW480 and HT-29. SERPINA3K-induced apoptosis of SW480 and HT-29 was rescued by interference with Fas ligand (FasL) small hairpin RNA. Moreover, SERPINA3K increased the expression of FasL and activated caspase-8. Peroxisome proliferator-activated receptor γ (PPARγ), a transcription factor of FasL, was also upregulated by SERPINA3K in a dose-dependent manner. The upregulation effect of FasL induced by SERPINA3K was reversed after interference with PPARγ small interfering RNA. These results demonstrated that SERPINA3K-induced SW480 and HT-29 cell apoptosis was mediated by the PPARγ/Fas/FasL signaling pathway. Therefore, our study provides additional insight into the direct anti-tumor function by inducing tumor cell apoptosis of SERPINA3K in colorectal tumors.

Association of Pro12Ala (rs1801282) variant of PPAR gamma with rheumatoid arthritis in a Pakistani population

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) belongs to a receptor superfamily of ligand-activated transcription factors, encoded by PPARG gene. Role of PPARγ has been well established in variety of metabolic disorders and in regulation of inflammation. In the present study, we aimed to investigate the association of PPARG (Pro12Ala; rs1801282) in clinically definite Pakistani Rheumatoid Arthritis (RA) patients and matching controls. The genotypes of the Pro12Ala variant in the PPARG were determined in a sample of 300 Pakistanis, including 150 RA cases and 150 controls. The genotyping was performed using Amplification Refractory Mutation System-Polymerase Chain Reaction (ARMS-PCR) method, and the data was analyzed through Graphpad Prism 5 V software. Allele-specific primer set (two forward: PPARG-F1, PPARG-F2 and a common reverse primer: PPARG-R) was used for amplification, and the product was resolved on 2 % agarose gel. The CC (ProPro) genotype has higher frequency in controls than RA cases [75 (50.0 %) vs. 51 (34.0 %)], whereas the CG (ProAla) genotype has relatively same frequencies in both cases and controls [72 (48.0 %) vs. 70 (46.6 %)]. However, significantly higher frequency of GG (AlaAla) genotype was observed in cases [27 (18.0 %) vs. 5 (3.3 %); χ2 18.54; p < 0.0001]. Furthermore, the minor allele G has significantly higher allele frequency in cases having same trend and direction of association (OR 1.991(1.412-2.808); p < 0.0001). These observations suggest that Pro12Ala (rs1801282), a coding variant in the PPARG gene, is associated with Rheumatoid Arthritis in Pakistanis.

Oral administration of Lactobacillus reuteri GMNL-263 improves insulin resistance and ameliorates hepatic steatosis in high fructose-fed rats

BACKGROUND

Type 2 diabetes mellitus (DM), characterized by peripheral insulin resistance, is the most common form of diabetes. Probiotics are live micro-organisms that, when administered in adequate amounts, confer delaying effect on DM development. In this study, the effects Lactobacillus reuteri GMNL-263 (Lr263), a new probiotic strain developed by our laboratory, on insulin resistance and the development of hepatic steatosis in high-fructose fed rats were explored. Furthermore, the relevant regulatory pathways involved were also investigated.

METHOD

Male Sprague-Dawley rats were fed a high-fructose diet with or without Lr263 administration for 14 weeks. The composition of fecal microbiota, oral glucose tolerance, glycated haemoglobin, insulin, leptin, C-peptide, and incretins were measured. The markers of liver injury, serum and hepatic lipids profile, activity of hepatic antioxidant enzyme, and proinflammatory cytokines in adipose tissue were investigated. Additionally, the expression of hepatic lipogenic genes and insulin signaling related genes in adipose tissue were also studied. Liver sections were examined for hepatic steatosis using hematoxylin-eosin staining.

RESULTS

The levels of serum glucose, insulin, leptin, C-peptide, glycated hemoglobin, GLP-1, liver injury markers, lipid profile in serum and liver were significantly increased in high-fructose-fed rats. However, after Lr263 administration, the elevation of these parameters was significantly suppressed. Feeding of Lr263 reversed the decreased number of bifidobacterium species and lactobacillus species and increased number of clostridium species induced by high fructose treatment. The decreased activities of hepatic antioxidant enzymes in HFD rats were dramatically reversed by Lr263 treatment. Concentrations of IL-6 and TNF-α in adipose tissue which were elevated in high fructose treatment were markedly decreased after Lr263 feeding. Decreased levels of PPAR-γ and GLUT4 mRNA after high fructose treatment were significantly enhanced by Lr263 administration. Lr263 consumption normalized the increased lipogenic gene (Srebp-1c, FAS, and Elvol6) expressions stimulated by high fructose. Administration of Lr263 significantly ameliorated hepatic steatosis observed in high fructose treated rats.

CONCLUSION

Our study provided evidences clarifying the effectiveness of Lr263 on reducing insulin resistance as well as hepatic steatosis formation in high-fructose-fed rats and suggested that Lr263 may be a promising therapeutic agent in treating type 2 diabetes.

PPARγ agonists promote oligodendrocyte differentiation of neural stem cells by modulating stemness and differentiation genes

Neural stem cells (NSCs) are a small population of resident cells that can grow, migrate and differentiate into neuro-glial cells in the central nervous system (CNS). Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor transcription factor that regulates cell growth and differentiation. In this study we analyzed the influence of PPARγ agonists on neural stem cell growth and differentiation in culture. We found that in vitro culture of mouse NSCs in neurobasal medium with B27 in the presence of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) induced their growth and expansion as neurospheres. Addition of all-trans retinoic acid (ATRA) and PPARγ agonist ciglitazone or 15-Deoxy-Δ^12,14-Prostaglandin J₂ (15d-PGJ2) resulted in a dose-dependent inhibition of cell viability and proliferation of NSCs in culture. Interestingly, NSCs cultured with PPARγ agonists, but not ATRA, showed significant increase in oligodendrocyte precursor-specific O4 and NG2 reactivity with a reduction in NSC marker nestin, in 3–7 days. In vitro treatment with PPARγ agonists and ATRA also induced modest increase in the expression of neuronal β-III tubulin and astrocyte-specific GFAP in NSCs in 3–7 days. Further analyses showed that PPARγ agonists and ATRA induced significant alterations in the expression of many stemness and differentiation genes associated with neuro-glial differentiation in NSCs. These findings highlight the influence of PPARγ agonists in promoting neuro-glial differentiation of NSCs and its significance in the treatment of neurodegenerative diseases.

Lutein decreases oxidative stress and inflammation in liver and eyes of guinea pigs fed a hypercholesterolemic diet

Guinea pigs were fed a hypercholesterolemic diet (0.25 g/100 g cholesterol) and randomly allocated either to a Control group (n = 9) or to a Lutein (0.1 g/100 g) group (n = 10) for 12 weeks to evaluate oxidative stress and inflammation in both liver and eyes. Malondialdehyde (MDA) concentrations and inflammatory cytokines were measured as well as hepatic nuclear factor-kappaB (NF-κB) binding. Lutein concentrations were greater in eyes (P < 0.01) and liver (P < 0.001) in the Lutein group. All guinea pigs had high concentrations of hepatic cholesterol as well as high plasma ALT and AST levels indicative of liver injury. However, the Lutein group had 43% lower hepatic free cholesterol than the Controls (P < 0.05). Hepatic MDA and MDA in the eye were lower in the Lutein compared to the Control group (P < 0.05). Hepatic tumor necrosis factor-α was 32% lower in the Lutein group (P < 0.05). Lastly, the Lutein group presented lower NF-κB DNA binding activity than the Control group (P < 0.001). These results suggest that in the presence of high cholesterol, lutein exerts both antioxidant and anti-inflammatory effects, which can be explained by attenuated NF-κB DNA binding activity. Furthermore, results also suggest that lutein accumulates in the eyes of guinea pigs to protect against oxidative stress.

PPARgamma Agonists: Potential as Therapeutics for Neovascular Retinopathies

The angiogenic, neovascular proliferative retinopathies, proliferative diabetic retinopathy (PDR), and age-dependent macular degeneration (AMD) complicated by choroidal neovascularization (CNV), also termed exudative or “wet” AMD, are common causes of blindness. The antidiabetic thiazolidinediones (TZDs), rosiglitazone, and troglitazone are PPARγ agonists with demonstrable antiproliferative, and anti-inflammatory effects, in vivo, were shown to ameliorate PDR and CNV in rodent models, implying the potential efficacy of TZDs for treating proliferative retinopathies in humans. Activation of the angiotensin II type 1 receptor (AT1-R) propagates proinflammatory and proliferative pathogenic determinants underlying PDR and CNV. The antihypertensive dual AT1-R blocker (ARB), telmisartan, recently was shown to activate PPARγ and improve glucose and lipid metabolism and to clinically improve PDR and CNV in rodent models. Therefore, the TZDs and telmisartan, clinically approved antidiabetic and antihypertensive drugs, respectively, may be efficacious for treating and attenuating PDR and CNV humans. Clinical trials are needed to test these possibilities.

Peroxisome proliferator-activated receptors in the modulation of the immune/inflammatory response in atherosclerosis

Inflammation has been recognized as an important hallmark of atherosclerosis. The pharmacological activation of PPAR-γ by the thiazolidinediones in diabetes, and of PPAR-α by the fibrates in hyperlipidemia has been shown to help to reduce inflammatory markers in preclinical and clinical studies. PPARs are known to modulate immune pathways through at least three different mechanisms: by direct binding to PPRE of anti-inflammatory cytokines genes; by transrepression of transcription factors like NF-κB and AP-1; or by corepression. The regulation of the inflammatory pathways by PPARs can be achieved on each one of the cells involved in the atherosclerotic process, that is, monocytes, macrophages, T cells, endothelial cells, and smooth muscle cells. Moreover, as each of these cellular components is interconnected with each other, PPAR activation in one cell type could affect the other ones. As activation of PPARs has clear ant-inflammatory benefits, PPARs ligands should be considered as a new therapeutical approach to ameliorate the exacerbated immune response in atherosclerotic diseases.

A Role for PPARgamma in the Regulation of Cytokines in Immune Cells and Cancer

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor and a member of the nuclear receptor superfamily. PPARγ and its ligands appear to serve diverse biological functions. In addition to the well-studied effects of PPARγ on metabolism and cellular differentiation, abundant evidence suggests that PPARγ is an important regulator of the immune system and cancers. Since cytokines are not only key modulators of inflammation with pro- and anti-inflammatory functions but they also can either stimulate or inhibit tumor growth and progression, this review summarizes the role for PPARγ in the regulation of cytokine production and cytokine-mediated signal transduction pathways in immune cells and cancer.

Role of peroxisome proliferator-activated receptor gamma and its ligands in the treatment of hematological malignancies

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a multifunctional transcription factor with important regulatory roles in inflammation, cellular growth, differentiation, and apoptosis. PPARgamma is expressed in a variety of immune cells as well as in numerous leukemias and lymphomas. Here, we review recent studies that provide new insights into the mechanisms by which PPARgamma ligands influence hematological malignant cell growth, differentiation, and survival. Understanding the diverse properties of PPARgamma ligands is crucial for the development of new therapeutic approaches for hematological malignancies.

Activated and inactivated PPARs-γ modulate experimentally induced colitis in rats

Background

This study sought to define the mechanism by which PPAR-γ ligands affect the course of experimentally induced colitis in rats.

Material/Methods

Inflammation was induced in Wistar rats by a single rectal administration of 2,4,6,-trinitrobenzene sulfonic acid (TNBS). The antagonist of PPARγ antagonist, bisphenol A diglycidyl ether (BADGE), was administrated intraperitoneally 120 mg/kg 4 times every other day. Rosiglitazone 8 mg/kg was administrated by gastric tube 4 times. Body weight was measured daily. After killing, the large intestinal tissue was weighed and collected for histopathologic and immunoenzymatic tests. Levels of IL-6, IL-10, and myeloperoxidase (MPO) were determined in serum and in intestinal homogenates.

Results

Rats receiving rosiglitazone had higher body weight, whereas large intestine weight/length ratio was lower; histology showed fewer inflammatory markers. Rats receiving TNBS and TNBS along with BADGE had more intensive inflammatory changes. Rosiglitazone alone decreased expression of IL-6; used with TNBS it decreased expression of MPO in intestinal tissue, yet did not increase the expression of IL-10. Decreased levels of MPO indicate reduced neutrophil-dependent immune response. The antagonist of PPAR-γ increased IL-6 in serum and decreased IL-10 in intestinal homogenates. Bisphenol A diglycidyl ether administrated to healthy animals increases serum IL-6 levels.

Conclusions

Rosiglitazone inhibits experimental inflammation; administration of its selective antagonist abolishes this protective influence. Rosiglitazone inhibits expression of proinflammatory IL-6 and does not affect IL-10. Agonists of PPARs-γ are possibilities for inflammatory bowel disease prevention. Exogenous substances blocking PPARs-γ may contribute to development or relapse of nonspecific inflammatory bowel diseases.

Peroxisome proliferator-activated receptor γ ligands regulate neural stem cell proliferation and differentiation in vitro and in vivo

Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a family of ligand-activated nuclear receptors and its ligands are known to control many physiological and pathological situations. Its role in the central nervous system has been under intense analysis during the last years. Here we show a novel function for PPARγ in controlling stem cell expansion in the adult mammalian brain. Adult rats treated with pioglitazone, a specific ligand of PPARγ, had elevated numbers of proliferating progenitor cells in the subventricular zone and the rostral migratory stream. Electron microscopy analysis also showed important changes in the subventricular zone ultrastructure of pioglitazone-treated animals including an increased number of migratory cell chains. These results were further confirmed in vitro. Neurosphere assays revealed significant increases in the number of neurosphere forming cells from pioglitazone- and rosiglitazone (two specific ligands of PPARγ receptor)-treated cultures that exhibited enhanced capacity for cell migration and differentiation. The effects of pioglitazone were blocked by the PPARγ receptor antagonists GW9662 and T0070907, suggesting that its effects are mediated by a mechanism dependent on PPARγ activation. These results indicate for the first time that activation of PPARγ receptor directly regulates proliferation, differentiation, and migration of neural stem cells in vivo.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations

BACKGROUND

Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis.

DISCUSSION

The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFβ1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

Association between peroxisome proliferator-activated receptor-γ gene polymorphism (Pro12Ala) and Helicobacter pylori infection in gastric carcinogenesis

OBJECTIVE

Helicobacter pylori infection is accompanied by inflammatory processes leading to peptic ulcer and gastric cancer in the minority of infected individuals. The interaction between H. pylori virulence factors, host defense mechanisms and environmental factors determine the outcome of clinical manifestations. One of the host factors involved in the processes of inflammation and carcinogenesis is the peroxisome proliferator-activated receptor-γ (PPAR-γ) molecule. The present case-control study aimed to determine polymorphism of PPAR-γ gene and its association with H. pylori infection and gastrointestinal diseases (peptic ulcer and non-cardia gastric cancer) in Iranian patients.

MATERIALS AND METHODS

One hundred and fifty-five patients with upper gastrointestinal diseases (76 peptic ulcer and 79 non-cardia gastric cancer) and 152 matched controls were genotyped for PPAR-γ gene polymorphism (Pro12Ala) by the PCR-RFLP method. Infection with H. pylori was confirmed by histology, the rapid urease test (RUT) and ELISA assay (IgG anti-H. pylori).

RESULTS

The frequency of PPAR-γ G (Ala 12) allele was significantly higher in H. pylori positive patients with non-cardia gastric cancer than in controls (22.8% vs. 3.9%, p = 0.027; OR = 3.28; 95% CI = 1.21-8.89), But there was no significant difference without infection (p = 0.7). Moreover, the PPAR-γ polymorphism was not associated with peptic ulcer in the presence or absence of H. pylori infection.

CONCLUSION

Our results indicated PPAR-γ G allele may be an important contributor to non-cardia gastric cancer in Iranian H. pylori infected patients.

Fat intake interacts with polymorphisms of Caspase9, FasLigand and PPARgamma apoptotic genes in modulating Crohn's disease activity

BACKGROUND & AIMS

Crohn's disease (CD) is a multifactorial disease where resistance to apoptosis is one major defect. Also, dietary fat intake has been shown to modulate disease activity. We aimed to explore the interaction between four single nucleotide polymorphisms (SNPs) in apoptotic genes and dietary fat intake in modulating disease activity in CD patients.

METHODS

Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) techniques were used to analyze Caspase9+93C/T, FasLigand-843C/T, Peroxisome Proliferator-Activated Receptor gamma+161C/T and Peroxisome Proliferator-Activated Receptor gamma Pro12Ala SNPs in 99 patients with CD and 116 healthy controls. Interactions between SNPs and fat intake in modulating disease activity were analyzed using regression analysis.

RESULTS

None of the polymorphisms analyzed influenced disease susceptibility and/or activity, but a high intake of total, saturated and monounsaturated fats and a higher ratio of n-6/n-3 polyunsaturated fatty acids(PUFA), was associated with a more active phenotype (p < 0.05). We observed that the detrimental effect of a high intake of total and trans fat was more marked in wild type carriers of the Caspase9+93C/T polymorphism [O.R(95%CI) 4.64(1.27-16.89) and O.R(95%CI) 4.84(1.34-17.50)]. In the Peroxisome Proliferator-Activated Receptor gamma Pro12Ala SNP, we also observed that a high intake of saturated and monounsaturated fat was associated to a more active disease in wild type carriers [OR(95%CI) 4.21(1.33-13.26) and 4.37(1.52-12.51)]. Finally, a high intake of n-6 PUFA was associated with a more active disease in wild type carriers for the FasLigand-843C/T polymorphism [O.R(95%CI) 5.15(1.07-24.74)].

CONCLUSIONS

To our knowledge, this is the first study to disclose a synergism between fat intake and SNPs in apoptotic genes in modulating disease activity in CD patients.