Decreased hepatic peroxisome proliferator-activated receptor-γ contributes to increased sensitivity to endotoxin in obstructive jaundice

AIM: To investigate the role of hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) in increased susceptibility to endotoxin-induced toxicity in rats with bile duct ligation during endotoxemia.METHODS: Male Sprague-Dawley rats were subjected to bile duct ligation (BDL). Sham-operated animals served as controls. DNA binding were determined by polymerase chain reaction, Western blotting analysis,and electrophoretic mobility shift assay, respectively.BDL and sham-operated rats received a non-lethal dose of intraperitoneal lipopolysaccharide (LPS) injection (3 mg/kg, i.p.). Additionally, the potential beneficial effects of the PPAR-γ agonist rosiglitazone were determined in BDL and sham-operated rats treated with a non-lethal dose of LPS. Survival was assessed in BDL rats treated with a non-lethal dose of LPS and in sham-operatedrats treated at a lethal dose of LPS (6 mg/kg, i.p.).RESULTS: PPAR-γ activity in rats undergoing BDL wassignificantly lower than in the sham-controls. Hepatic PPAR-γ gene expression was downregulated at both them RNA and protein levels. In a parallel group, serumlevels of pro-inflammatory cytokines were nearly unde-tectable in the sham-operated rats. When challenged with a non-lethal dose of LPS (3 mg/kg), the BDL ratshad approximately a 2.4-fold increase in serum IL-6,a 2.7 fold increase in serum TNF-α, 2.2-fold increasein serum IL-1 and 4.2-fold increase in serum ALT. Thesurvival rate was significantly lower as compared with that in sham-operated group. Additionally, rosiglitazone significantly reduced the concentration of TNF-α, IL-1β, IL-6 and ALT in sham-operated rats, but not in BDL rats, in response to LPS (3 mg/kg). Also, the survival was improved by rosiglita zone in sham-operated rats challenged with a lethal dose of LPS, but not in BDL rats, even with a non-lethal dose of LPS (3 mg/kg).CONCLUSION: Obstructive jaundice downregulates hepatic PPAR-γ expression, which in turn may contributeto hypersensitivity towards endotoxin.

Potential effects of curcumin on peroxisome proliferatoractivated receptor-γ in vitro and in vivo

Natural peroxisome proliferator-activated receptor-γ(PPAR-γ) agonists are found in food and may be important for health through their anti-inflammatory properties. Curcumin(Cur) is a bright yellow spice, derived from the rhizome of Curcuma longa Linn. It has been shown to have many biological properties that appear to operate through diverse mechanisms. Some of these potentially beneficial effects of Cur are due to activation of the nuclear transcription factor PPAR-γ. It is reported(using in vitro and in vivo models) that Cur plays a potential role against several diseases. In this review article, we present the current literature on the effects of Cur on the modulation of inflammatory processes that are mediated through PPAR-γ.

Peroxisome proliferator activated receptor-γ and the ubiquitin-proteasome system in colorectal cancer

Peroxisome proliferator activated receptor-γ (PPARγ), a transcription factor of the nuclear receptor superfamily plays a significant role in colorectal cancer pathogenesis. In most experimental systems PPARγ activation has tumor suppressing effects in the colon. PPARγ is regulated at multiple levels by the ubiquitin-proteasome system (UPS). At a first level, UPS regulates PPARγ transcription. This regulation involves both PPARγ transcription specific factors and the general transcription machinery. At a second level UPS regulates PPARγ and its co-factors themselves, as PPARγ and many co-factors are proteasome substrates. At a third level of regulation, transduction pathways working in parallel but also having interrelations with PPARγ are regulated by the UPS, creating a network of regulation in the colorectal carcinogenesisrelated pathways that are under UPS control. Activation of PPARγ transcription by direct pharmacologic activators and by stabilization of its molecule by proteasome inhibitors could be strategies to be exploited in colorectal cancer treatment.

Peroxisome proliferator-activated receptor-γ 34C>G polymorphism and colorectal cancer risk: A meta-analysis

AIM: To investigate the association between peroxisome proliferator-activated receptor-γ (PPAR-γ ) gene polymorphism 34 C>G and colorectal cancer (CRC),a meta-analysis review was performed in this report.METHODS: A systematic literature search and selection of eligible relevant studies were carried out.Nine independent studies with a total number of 4533 cases and 6483 controls were included in the meta-analysis on the association between polymorphism 34 C>G and CRC.RESULTS: There was no evidence for the association between PPAR-γ 34 C>G and CRC if all of the subjects in the nine studies were included.However,CG + GG showed a marginally significant difference from CC (OR = 0.84,95% CI: 0.69-1.01,P = 0.07) in random-effect model.Stratified meta-analysis indicated that PPAR-γ 34 C>G was associated with colon cancer (OR = 0.8,95% CI: 0.65-0.99,P = 0.04) in random-effect model,and the G allele decreased colon cancer risk.No significant association was observed between PPAR-γ 34 C>G and rectal cancer.CONCLUSION: PPAR-γ 34 C>G is associated with colon cancer risk,but not associated with CRC and rectal cancer risk.

Peroxisome Proliferator-activated Receptor-γ2 Pro12Ala and C-689T Polymorphisms and Haplotypes Affect the Profiles of Coronary Heart Disease in Diabetic Chinese People

Objectives Peroxisome proliferator-activated receptor-γ2（PPARγ2） variant Pro12Ala was demonstrated with risk of coronary heart disease （CHD） and type 2 diabetes mellitus （T2DM）. Another variant C-689T in the promoter was reported with lower receptor activity but lack of reports on association between C-689T and CHD or T2DM. Methods A total of 351 subjects without CHD and T2DM （controls） and 125 patients with CHD and T2DM （cases） were enrolled in our case-control study. Polymerase chain reaction-restricted fragments length polymorphism （PCR-RFLP） was used to detect Pro12Ala and C-689T polymorphisms. And effects on CHD merged with T2DM of the two polymorphisms were analyzed in individual and haplotype analyses. Results In the study, Pro12Pro, Pro12Ala and Ala12Ala genotype frequencies were 92.9%, 6.8% and 0.3% in controls; 92.8%, 7.2% and 0.0% in cases respectively whilst CC, CT and TT genotype frequencies were 93.4%, 6.3% and 0.3% in controls; 92.8%, 7.2% and 0.0% in cases respectively. Pro12Ala and C-689T polymorphisms were in strong linkage disequilibrium （D＇=0.81, P=0.000） and the observed haplotype frequency of Pro-C, Pro-T, Ala-C and Ala-T was 0.957, 0.006, 0.008 and 0.028 respectively. No significant associations were detected between the two polymorphisms and CHD merged with T2DM in either individual or haplotype analyses. In subjects with obesity [body mass index （BMI）≥25 kg/m^2], we found that both Pro12Ala and C-689T polymorphisms were associated with BMI. In haplotype analyses, we found that Pro12Ala and C-689T haplotypes had associations with systolic blood pressure in total population, with BMI, waist circle and total cholesterol（TC） in obesity subgroup and with fasting blood glucose and TC in males. Conclusions PPARγ2 Pro12Ala and C-689T polymorphisms and haplotypes affect the profiles of CHD merged with T2DM in Chinese Han people.

Peroxisome proliferator-activated receptor gamma as a therapeutic target for hepatocellular carcinoma:Experimental and clinical scenarios

Hepatocellular carcinoma(HCC)is the most common type of liver cancer worldwide.Viral hepatitis is a significant risk factor for HCC,although metabolic syndrome and diabetes are more frequently associated with the HCC.With increasing prevalence,there is expected to be>1 million cases annually by 2025.Therefore,there is an urgent need to establish potential therapeutic targets to cure this disease.Peroxisome-proliferator-activated receptor gamma(PPARγ)is a ligand-activated transcription factor that plays a crucial role in the pathophysiology of HCC.Many synthetic agonists of PPARγsuppress HCC in experimental studies and clinical trials.These synthetic agonists have shown promising results by inducing cell cycle arrest and apoptosis in HCC cells and preventing the invasion and metastasis of HCC.However,some synthetic agonists also pose severe side effects in addition to their therapeutic efficacy.Thus natural PPARγagonists can be an alternative to exploit this potential target for HCC treatment.In this review,the regulatory role of PPARγin the pathogenesis of HCC is elucidated.Furthermore,the experimental and clinical scenario of both synthetic and natural PPARγagonists against HCC is discussed.Most of the available literature advocates PPARγas a potential therapeutic target for the treatment of HCC.

Differential Mechanisms of the Effect of Peroxisome Proliferator-Activated Receptor Gamma Agonists on Bleomycin-Induced Lung Fibrosis

Background and Objectives: Peroxisome proliferator-activated receptor-g (PPAR-g) is a nuclear receptor whose activation regulates inflammation and fibrosis in various organs. We aimed to investigate the effect of two PPAR-g ligands, telmisartan and rosiglitazone, on lung injury and fibrosis induced by intratracheal bleomycin (BLM). Methods: Lung injury and fibrosis was induced in female C57Bl/6 mice by intratracheal instillation of 1.0 mg/kg of BLM. Some of the animals received rosiglitazone intraperitoneally or telmisartan in drinking water. Bronchoalveolar lavage (BAL) was performed 2, 7, 14 or 21 days after BLM instillation for cell counting and measurement of mediators in the lung. In a separate series, the lungs were sampled for collagen assay and histopathological evaluation. Results: Treatment with rosiglitazone or telmisartan significantly attenuated the BLM-induced increases in lung collagen content, pathological score, and inflammatory cells in BAL fluid. Rosiglitazone significantly suppressed BLM-induced elevation of TGF-b1, MCP-1, and IL-6 levels in the lung. In contrast, telmisartan made no changes in these cytokines, whereas it mitigated the BLM-induced increase in prostaglandin F2a in the lung. Higher concentrations of rosiglitazone and telmisartan attenuated proliferation of lung fibroblasts in vitro. Conclusions: Two PPAR-g ligands, rosiglitazone and telmisartan, exert protective effects on BLM-induced lung fibrosis through the suppression of different profibrotic mediators.

Activation of G-protein-coupled receptor 39 reduces neuropathic pain in a rat model

Activated G-protein-coupled receptor 39(GPR39)has been shown to attenuate inflammation by interacting with sirtuin 1(SIRT1)and peroxisome proliferator-activated receptor-γcoactivator 1α(PGC-1α).However,whether GPR39 attenuates neuropathic pain remains unclear.In this study,we established a Sprague-Dawley rat model of spared nerve injury-induced neuropathic pain and found that GPR39 expression was significantly decreased in neurons and microglia in the spinal dorsal horn compared with sham-operated rats.Intrathecal injection of TC-G 1008,a specific agonist of GPR39,significantly alleviated mechanical allodynia in the rats with spared nerve injury,improved spinal cord mitochondrial biogenesis,and alleviated neuroinflammation.These changes were abolished by GPR39 small interfering RNA(siRNA),Ex-527(SIRT1 inhibitor),and PGC-1αsiRNA.Taken together,these findings show that GPR39 activation ameliorates mechanical allodynia by activating the SIRT1/PGC-1αpathway in rats with spared nerve injury.

Inhibition of proliferation and transforming growth factor β3 protein expression by peroxisome proliferators-activated receptor γ ligands in human uterine leiomyoma cells

Background Rosiglitazone is known as the most potent and specific peroxisome proliferators-activated receptor γ （PPAR-γ） ligand. It has potentially far-reaching effects on pathophysiological processes, from cancer to atherosclerosis and diabetes. However, it is not clear whether rosiglitazone affects the protein expression of transforming growth factor β3 （TGF-β3） and the cell proliferation in human uterine leiomyoma cells in vitro.Methods Human uterine leiomyoma tissues were dissected and cultured. Cells were divided into 5 groups： one control group and other four groups with different concentrations of rosiglitazone （10^-7, 10^-8, 10^-9 and 10^-10 mol/L）. Cells were cultured for 72 hours in serum-free Dulbecco＇s modified Eagle＇s medium. MTT reduction assay was used to detect the cell proliferation. Reverse transcription polymerase chain reaction （RT-PCR） was used to detect the mRNA expression of PPAR-γ and TGF-β3. Immunofluorescence staining was used to detect the expressions of PPAR-γ and TGF-β3 proteins. Results MTT reduction assay indicated that the treatment with rosiglitazone （from 10^-7 to 10^-9 mol/L） resulted in an inhibition of the cell growths after 72 hours （P〈0.01）. RT-PCR analysis revealed that 10^-7 mol/L rosiglitazone significantly affected the gene expression at 72-hour： PPAR-γ mRNA expression was up-regulated and TGF-β3 mRNA was down-regulated and rosiglitazone at the concentration of 10-7 mol/L affected these most effectively （P〈0.01）. Immunofluorescence staining demonstrated that treatment with 10^-7 mol/L rosiglitazone resulted in the significant changes of PPAR-γ and TGF-β3 protein expressions compared with the other treatment groups and the control group at 72-hour （P〈0.01）. All the effects of rosiglitazone on uterine leiomyoma cells were dose- and time-dependent in vitro. Conclusions The present study demonstrates that the PPAR-γ activator, rosiglitazone, inhibits the cell proliferation partly through the regulations of PPAR-γ and TGF-β3 expressions. The cross-talk between the signal pathways of PPAR-γ and TGF-β3 may be involved in the process.

Construction and identification of the recombinant adenovirus vector carrying a small interfering RNA targeting the peroxisome proliferator-activated receptor-γ

Background Steroid-induced osteonecrosis of the femoral head （ONFH） is a common clinical disease,with a high disability rate.At present,efficient prevention and treatment of steroid-induced ONFH is still lacking.The peroxisome proliferator-activated receptor-γ （PPARγ） is recognized as an important pathogenic gene for the development of steroid-induced ONFH.RNA interference （RNAi） is a tool for functional gene analysis,which has been successfully used to down-regulate the levels of specific target proteins.Therefore,down-regulation of PPARγ expression by RNAi may prevent the incidence of steroid-induced ONFH.Methods According to the principles of siRNA design,three duplex siRNA sequences （971-989,1253-1271 and 1367-1385） derived from the PPARy gene （NM_001082148） were synthesized.These duplexes were annealed,purified and ligated into 1.0-cytomegalovirus （CMV） shuttle vector.The shuttle vector was transfected into HEK293 cells.The HEK293 generated recombinant adenovirus vector carrying PPARγ siRNA sequences was purified and the titer of recombinant adenovirus was determined.Results After the annealing of single-strand DNA oligo encoding short hairpin RNA （shRNA） sequences,products were identified by gel electrophoresis.These products were ligated into the 1.0-CMV shuttle vector and the recombinant shuttle vectors 1.0-CMV-971,1.0-CMV-1253 and 1.0-CMV-1367 were constructed.These sequences of these recombinant vectors were confirmed.We then successfully constructed the recombinant adenovirus vector carrying siRNA targeting PPARγ.After purification,the virus titer was higher than 1010 plaque forming unit （PFU）/ml.Conclusion In this study,three recombinant adenovirus shuttle vectors carrying siRNA targeting PPARγ,including shuttle vectors 1.0-CMV-971,1.0-CMV-1253 and 1.0-CMV-1367,were successfully constructed and high titers of recombinant adenovirus were obtained.

Inhibition of peroxisome proliferator-activated receptor-γ in steroid-induced adipogenic differentiation of the bone marrow mesenchymal stem cells of rabbit using small interference RNA

Background Steroids inhibit osteogenic differentiation and decrease bone formation while concomitantly inducing adipose deposition in osteocytes.This leads to the fatty degeneration and necrosis of bone cells commonly seen in osteonecrosis of the femoral head.The peroxisome proliferator-activated receptor-γ （PPARγ） is an adipogenic transcription factor linked to the development of this disease and responsible for inducing adipogenesis over osteogenesis in bone marrow mesenchymal stem cells （BMSCs）.The aim of this study was to assess whether adipogenic differentiation could be suppressed,and thus osteogenic potential retained,by inhibiting PPARy expression in BMSCs.Methods Cells from the bone marrow of New Zealand rabbits were treated with 10-7 mol/L dexamethasone and infected with one of three small interference RNA （siRNA） adenovirus vectors （S1,S2,and S3） or non-targeting control siRNA （Con） and compared with dexamethasone-treated （model） and untreated （normal） cells.Cells were grown for 21 days and stained with Sudan Ⅲ for adipocyte formation.At various time points,cells were also assessed for changes in PPARγ,osteocalcin （OC）,Runx2,alkaline phosphatase （ALP） activity,and triglyceride （TG） content.Results Dexamethasone-treated model and control groups showed a significant increase in fatty acid-positive staining,which was inhibited in cells treated with PPARγ siRNA-treated,similar to normal untreated cells.All three siRNA groups significantly inhibited PPARγ mRNA and protein,adipocyte number,and TG content compared with the dexamethasonetreated model and control groups,matching that seen in normal cells.OC and Runx2 mRNA and protein,as well as ALP activity,were significantly higher in cells treated with siRNA against PPARγ,similar to that seen in the normal cells.These osteogenic markers were significantly lower in the dexamethasone-treated cell cultures.Conclusions The siRNA adenovirus vector targeting PPARγ can efficiently inhibit steroid-induced adipogenic differentiation in rabbit BMSCs and retain their osteogenic differentiation potential.

High density lipoprotein suppresses lipoprotein associated phospholipase A2 in human monocytes-derived macrophages through peroxisome proliferator-activated receptor-γ pathway

Background Lipoprotein-associated phospholipase A2 （Lp-PLA2） is mainly secreted by macrophages, serving as a specific marker of atherosclerotic plaque and exerting pro-atherogenic effects. It is known that high-density lipoprotein （HDL） plays an important role against atherosclerosis by inhibiting pro-inflammatory factors, however, the relationship between HDL and Lp-PLA2 remains elusive. Methods In this study, reverse transcription-polymerase chain reaction （RT-PCR）, Western blotting, and a platelet-activating factor （PAF） acetylhydrolase assay were performed to determine the Lp-PLA2 mRNA level, protein expression and activity in human monocyte-derived macrophages upon HDL treatment of different concentrations and durations. To investigate the underlying mechanism of HDL-induced Lp-PLA2 action, pioglitazone, a peroxisome proliferator-activated receptor-γ （PPARy） ligand, was introduced to human monocyte-derived macrophages and mRNA and protein levels of Lp-PLA2, as well as its activity, were determined. Results Lp-PLA2 mRNA levels, protein expression and activity were significantly inhibited in response to HDL treatment in a dose and time dependent manner in human monocyte-derived macrophages. Pioglitazone treatment （1-10 ng/ml） upregulated the Lp-PLA2 mRNA level, protein expression and activity in human monocyte-derived macrophages, while the effects were markedly reversed by HDL. In addition, pioglitazone resulted in a significant increase in PPARy phosphorylation in human monocyte-derived macrophages, which could be inhibited by HDL. Conclusion These findings indicate that HDL suppresses the expression and activity of Lp-PLA2 in human monocyte-derived macrophages, and the underlying mechanisms may be mediated through the PPARγ pathway.

Tagging single nucleotide polymorphisms in the PPAR-γ and RXR-α gene and type 2 diabetes risk:a case-control study of a Chinese Han population

Peroxisome proliferator-activated receptor （PPAR-γ）,which is mainly involved in adipocyte differentiation, has been suggested to play an important role in the pathogenesis of insulin resistance and atherosclerosis. We investigated the frequencies of two common tagging polymorphisms of the PPAR-γ gene and two of PPAR-α with minor allele frequency （MAF）≥ 0.05 in the Chinese Han population and analyzed the correlation between the different genotypes and the risk of type 2 diabetes mellitus （T2DM）. TaqMan assay was performed to test the genotypes in T2DM patients （n = 1,105） and normal controls （n = 1,107）. Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs17817276GG, rs3856806CT and rs3856806CT/TT of PPAR-γ were associated with T2DM, P = 0.023,0.037 and 0.018, respectively. Furthermore, the prevalence of haplotype GT in PPAR-γ was less frequent in the case subjects （0.3%） than in the controls （1.9%） [P 0.001,OR（95%CI）=0.13 （0.06-0.31）]. Patients with genotype TT of rs3856806 had a higher serum level of adiponectin than those with the genotype CC and CT （P = 0.031 and 0.038, respectively）. There was no statistically significant difference between patients and controls in genotype distribution of rs6537944 and rs1045570 of the RXR-α gene. The present study suggests that the variant genotypes in the PPAR-γ gene could decrease the risk for the development of T2DM in the Chinese Han population.

Osteoporosis and obesity: Role of Wnt pathway in human and murine models

Studies concerning the pathophysiological connection between obesity and osteoporosis are currently an intriguing area of research.Although the onset of these two diseases can occur in a different way,recent studies have shown that obesity and osteoporosis share common genetic and environmental factors.Despite being a risk factor for health,obesity has traditionally been considered positive to bone because of beneficial effect of mechanical loading,exerted by high body mass,on bone formation.However,contrasting studies have not achieved a clear consensus,suggesting instead that excessive fat mass derived from obesity condition may not protect against osteoporosis or,even worse,could be rather detrimental to bone.On the other hand,it is hitherto better established that,since adipocytes and osteoblasts are derived from a common mesenchymal stem cell precursor,molecules that lead to osteoblastogenesis inhibit adipogenesis and vice versa.Here we will discuss the role of the key molecules regulating adipocytes and osteoblasts differentiation,which are peroxisome proliferators activated receptor-γand Wnts,respectively.In particular,wewill focus on the role of both canonical and non-canonical Wnt signalling,involved in mesenchymal cell fate regulation.Moreover,at present there are no experimental data that relate any influence of the Wnt inhibitor Sclerostin to adipogenesis,although it is well known its role on bone metabolism.In addition,the most common pathological condition in which there is a simultaneous increase of adiposity and decrease of bone mass is menopause.Given that postmenopausal women have high Sclerostin level inversely associated with circulating estradiol level and since the sex hormone replacement therapy has proved to be effective in attenuating bone loss and reversing menopause-related obesity,we hypothesize that Sclerostin contribution in adipogenesis could be an active focus of research in the coming years.

Rhinacanthus nasutus leaf improves metabolic abnormalities in high-fat diet-induced obese mice

Objective:To investigate the effect of Rhinacanthus nasutus(R.nasutus) leaf extract on impaired glucose and lipid metabolism in obese ICR mice.Methods:Obesity was induced in the male ICR mice by feeding them a high-fat diet(60 kcal%fat) for 12 weeks.After the first six weeks of the diet,the obese mice were administered with the water extract of R.nasutus leaves at 250 and 500 mg/kg per day for the next six weeks.Subsequently,the blood glucose,lipid profiles,insulin,leptin,and adiponectin levels were measured.The liver and adipose tissues were excised for histopathological examination and protein expression study.Results:After six weeks of the treatment,R.nasutus extract(at 250 and 500 mg/kg per day) was found to reduce the elevated blood glucose level,improve the insulin sensitivity,decrease the serum leptin,and increase the serum adiponectin levels.The obese mice treated with R.nasutus were found to have a reduction in the increased lipid concentrations in their serum and liver tissues.Moreover,treatment with R.nasutus reduced the fat accumulation in the liver and the large adipocyte size in the fat tissues.Interestingly,the administration with R.nasutus extract was marked by an increase in the hepatic peroxisome proliferators-activated receptor alpha,fat cell adiponectin,and glucose transporter 4 proteins.Conclusions:To the best of our knowledge,the present study is the first report on the impact of R.nasutus extract in improving the impaired glucose and lipid metabolism in high-fat diet-induced obesity in mice via stimulating the insulin sensitivity in the liver and adipose tissues.

Neuroprotection mediated by the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage

The Wnt/Frizzled signaling pathway participates in many inflammation-linked diseases. However, the inflammatory response mediated by the Wnt/Frizzled signaling pathway in experimental subarachnoid hemorrhage has not been thoroughly investigated. Consequently, in this study, we examined the potential role of the Wnt/Frizzled signaling pathway in early brain injury in rat models of subarachnoid hemorrhage.Simultaneously, possible neuroprotective mechanisms were also investigated. Experimental subarachnoid hemorrhage rat models were induced by injecting autologous blood into the prechiasmatic cistern. Experiment 1 was designed to examine expression of the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage. In total, 42 adult rats were divided into sham(injection of equivalent volume of saline), 6-, 12-, 24-, 48-, 72-hour, and 1-week subarachnoid hemorrhage groups. Experiment 2 was designed to examine neuroprotective mechanisms of the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage. Rats were treated with recombinant human Wnt1(rhwnt1), small interfering Wnt1(siwnt1) RNA, and monoclonal antibody of Frizzled1(anti-Frizzled1) at 48 hours after subarachnoid hemorrhage. Expression levels of Wnt1, Frizzled1, β-catenin, peroxisome proliferator-activated receptor-γ, CD36, and active nuclear factor-κB were examined by western blot assay and immunofluorescence staining. Microglia type conversion and inflammatory cytokine levels in brain tissue were examined by immunofluorescence staining and enzyme-linked immunosorbent assay. Our results show that compared with the sham group, expression levels of Wnt1, Frizzled1, and β-catenin were low and reduced to a minimum at 48 hours, gradually returning to baseline at 1 week after subarachnoid hemorrhage. rhwnt1 treatment markedly increased Wnt1 expression and alleviated subarachnoid hemorrhage-induced early brain injury(within 72 hours), including cortical cell apoptosis, brain edema, and neurobehavioral deficits, accompanied by increasing protein levels of β-catenin, CD36, and peroxisome proliferator-activated receptor-γ and decreasing protein levels of nuclear factor-κB. Of note, rhwnt1 promoted M2-type microglia conversion and inhibited release of inflammatory cytokines(interleukin-1β, interleukin-6, and tumor necrosis factor-α). In contrast, siwnt1 RNA and anti-Frizzled1 treatment both resulted in an opposite effect. In conclusion, the Wnt/Frizzled1 signaling pathway may participate in subarachnoid hemorrhage-induced early brain injury via inhibiting the inflammatory response, including regulating microglia type conversion and decreasing inflammatory cytokine release. The study was approved by the Animal Ethics Committee of Anhui Medical University and First Affiliated Hospital of USTC,Division of Life Sciences and Medicine, University of Science and Technology of China(approval No. LLSC-20180202) in May 2017.

Pioglitazone ameliorates retinal ischemia/reperfusion injury via suppressing NLRP3 inflammasome activities

AIM：To explore the role of Pioglitazone（Pio） on a mouse model of retinal ischemia/reperfusion（I/R） injury and to elucidate the potential mechanism.METHODS：Retinal ischemia was induced in mice by increasing the intraocular pressure,and Pio was administered 4 h though periocular injection before I/R.The number of cells in the ganglion cell layer（GCL） was counted 7 d after retinal I/R injury.Glial fibrillary acidic protein（GFAP）,nuclear factor-kappa B（NF-κB）,p38,phosphorylated-p38,PPAR-γ,interleukin-1β（IL-1β）,Toll-like receptor 4（TLR4）,NLRP3,cleaved caspase-1,caspase-1 were determined by real-time polymerase chain reaction and Western blotting.RESULTS：Pio promoted the survival of retinal cells in GCL following retinal I/R injury（P〈0.05）.Besides,retinal I/R injury stimulated the expression of GFAP and TLR4,which were partially reversed by Pio treatment（P0.05）.Retinal I/R injury-upregulated expression of NLRP3,cleaved caspase-1,IL-1β was attenuated after Pio treatment（P〈0.05）.Moreover,I/R injury induced activation of NF-κB and p38 were inhibited by Pio treatment（P〈0.05）.CONCLUSION：Pio promotes retinal ganglion cells survival by suppressing I/R-induced activation of TLR4/NLRP3 inflammasomes via inhibiting NF-κB and p38 phosphorylation.

Telmisartan but not Valsartan Inhibits TGF-β-mediated Accumulation of Extracelluar Matrix via Activation of PPARγ

Glomerulosclerosis, defined as phenotype transition of mesangial cell and deposition of extracelluar matrix, remains a chronic disease with excessive morbidity and mortality. The molecular mechanism underlying the suppression of mesangial cell activation is not fully understood. Since activation of peroxisome proliferators-activated receptor γ （PPARγ） has been proposed to decrease the effects of transforming growth factor-β （TGF-β） on glomerulosclerosis, we examined here whether and how telmisartan, an angiotensin Ⅱ type 1 receptor blocker with PPARγ-modulating activity, inhibited TGF-β-induced glomerulosclerosis in rat glomerular mesangial cells. Protein levels of PPARγ were detected by Western blot. Activation of PPARγ response element （PPRE） was analyzed by luciferase assays. Deposition of extracelluar matrix was tested by confocol laser scanning. The results showed that telmisartan, but not valsartan, another angiotensin Ⅱ type 1 receptor blocker, up-regulated PPARγ protein levels in a dose-dependent manner （P〈0.05）. Activation of PPRE, represented by luciferase activity, was also increased with higher concentration of telmisartan in a dose-dependent manner （P〈0.05）. Furthermore, telmisartan inhibited TGF-β-induced α-smooth muscle actin expression and collagen IV secretion in mesangial cells. GW9662, an inhibitor of PPAR-γ, blocked the inhibitory effects of telmisartan on TGF-β-induced glomerulosclerosis in mesangial cells. Our study indicates a benefit of telmisartan as a PPARγ agonist against TGF-β-induced mesangial cells activation in renal glomerulus. It may provide possibility that telmisartan works as a potential agent against diabetic nephropathy and hypertensive renal disease.

Application of the back-error propagation artificial neural network(BPANN) on genetic variants in the PPAR-γ and RXR-α gene and risk of metabolic syndrome in a Chinese Han population

This study was aimed to explore the associations between the combined effects of several polymorphisms in the PPAR-γ and RXR-α gene and environmental factors with the risk of metabolic syndrome by back-error propaga- tion artificial neural network （BPANN）. We established the model based on data gathered from metabolic syndrome patients （n = 1012） and normal controls （n = 1069） by BPANN. Mean impact value （MIV） for each input variable was calculated and the sequence of factors was sorted according to their absolute MIVs. Generalized multifactor dimensionality reduction （GMDR） confirmed a joint effect of PPAR-9＂ and RXR-a based on the results from BPANN. By BPANN analysis, the sequences according to the importance of metabolic syndrome risk fac- tors were in the order of body mass index （BMI）, serum adiponectin, rs4240711, gender, rs4842194, family history of type 2 diabetes, rs2920502, physical activity, alcohol drinking, rs3856806, family history of hypertension, rs1045570, rs6537944, age, rs17817276, family history of hyperlipidemia, smoking, rs1801282 and rs3132291. However, no polymorphism was statistically significant in multiple logistic regression analysis. After controlling for environmental factors, A1, A2, B1 and B2 （rs4240711, rs4842194, rs2920502 and rs3856806） models were the best models （cross-validation consistency 10/10, P = 0.0107） with the GMDR method. In conclusion, the interaction of the PPAR-γ and RXR-α gene could play a role in susceptibility to metabolic syndrome. A more realistic model is obtained by using BPANN to screen out determinants of diseases of multiple etiologies like metabolic syndrome.

Ameliorative effects of lutein on non-alcoholic fatty liver disease in rats

AIM: To investigate the therapeutic effects of lutein against non-alcoholic fatty liver disease(NAFLD) and the related underlying mechanism.METHODS: After 9 d of acclimation to a constant temperature-controlled room(20 ℃-22 ℃) under 12h light/dark cycles,male Sprague-Darley rats were randomly divided into two groups and fed a standard commercial diet(n = 8) or a high-fat diet(HFD)(n = 32) for 10 d.Animals receiving HFD were then randomly divided into 4 groups and administered with 0,12.5,25,or 50 mg/kg(body weight) per day of lutein for the next 45 d.At the end of the experiment,the perinephric and abdominal adipose tissues of the rats were isolated and weighed.Additionally,serum and liver lipid metabolic condition parameters were measured,and liver function and insulin resistance state indexes were assessed.Liver samples were collected and stained with hematoxylin eosin and Oil Red O,and the expression of the key factors related to insulin signaling and lipid metabolism in the liver were detected using Western blot and real-time polymerase chain reaction analyses.RESULTS: Our data showed that after being fed a high-fat diet for 10 d,the rats showed a significant gain in body weight,energy efficiency,and serum total cholesterol(TC) and triglyceride(TG) levels.Lutein supplementation induced fat loss in rats fed a highfat diet,without influencing body weight or energy efficiency,and decreased serum TC and hepatic TC and TG levels.Moreover,lutein supplementation decreased hepatic levels of lipid accumulation and glutamic pyruvic transaminase content,and also improved insulin sensitivity.Lutein administration also increased the expression of key factors in hepatic insulin signaling,such as insulin receptor substrate-2,phosphatidylinositol 3-kinase,and glucose transporter-2 at the gene and protein levels.Furthermore,high-dose lutein increased the expression of peroxisome proliferators activated receptor-α and sirtuin 1,which are associated with lipid metabolism and insulin signaling.CONCLUSION: These results demonstrate that lutein has positive effects on NAFLD via the modulation of hepatic lipid accumulation and insulin resistance.