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.

Functional Variant of C-689T in the Peroxisome Proliferator-Activated Receptor-γ2 Promoter is Associated with Coronary Heart Disease in Chinese Nondiabetic Han People

Objective To investigate the association between the polymorphism of C-689T in the peroxisome proliferator-activated receptor-γ2 （PPARγ2） promoter and coronary heart disease （CHD）. Methods This case-controlled study was conducted in nondiabetic Chinese Han people, which enrolled 455 patients with CHD （cases） and 693 subjects without CHD （controls）. Data of clinical indexes were collected, including height, body weight, waist circumstance, systolic blood pressure （SBP）, diastolic blood pressure （DBP）, smoking, drinking, physical activity, as well as body mass index （BMI）. Fasting blood glucose （FBG）, plasma total cholesterol （TC） and triglyceride （TG） levels were measured. Polymerase chain reaction-restricted fragments length polymorphism （PCR-RFLP） was used to determine the PPARγ2 promoter C-689→T substitution. The genotype distribution of PPARγ2 promoter C-689T, allelic frequency, clinical indexes, and laboratorial measurements were compared between the two groups. The effect of genotype on the risk of CHD was assessed using univariate and multivariate regression model. Results The genotype frequencies of CC, CT and TT in PPARγ2 promoter C-689T were 89.7%, 9.9% and 0.4% in the case group, and 93.1%, 6.6% and 0.3% in the control group, respectively （CC vs. CT＋TT, χ^2= 6.243, P=0.041）. Carriers of -689T allele （n=95） had significantly higher TC level than non-carriers （n=1053） （5.12±1.26 vs. 4.76±1.22 mmol/L, P=0.001）. Male carriers of -689T allele （n=51） were significantly higher in waist circumference, body weight, TC and TG than male non-carriers （n=656） （all P〈0.05）. In subjects whose BMI was over 25 kg/m2, carriers of -689T allele （n=82） had significantly higher levels of waist circumference, BMI, SBP and TC than non-carriers （n=231） （all p〈0.05）. The -689T allele was an independent risk factor for CHD （OR=1.668, 95%CI： 1.031-2.705, P=0.037） after adjusting for age, gender, waist circumference, body weight, BMI, smoking, physical activities, SBP, DBP, FBG, TC and TG level. Conclusion These data support the hypothesis that the -689T allele is associated with an increased risk of CHD, in Chinese Han people and correlates significantly with the profiles of CHD-related risk factors.

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.

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.

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.

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.

Resveratrol prevents interleukin-1 β-induced dysfunction of pancreatic β-cells

Objective：Interleukin-1β（IL-1β）plays an important role in the development of type 1 and type 2 diabetes mellitus.Resveratrol,a polyphenol,is known to have a wide range of pharmacological properties in vitro.In this research,we examined the effects of resveratrol on IL-1β-inducedβ-cell dysfunction.Methods：We first evaluated the effect of resveratrol on nitric oxide（NO）formation in RINm5F cells stimulated with IL-1βusing the Griess method.Next,we performed transient transfection and reporter assays to measure the transcriptional activity of peroxisome proliferator-activated receptor-γ（PPAR-γ）.We also used Western blotting analysis to assess the effect of resveratrol on inducible nitric oxide synthase（iNOS）expression and nuclear factor-κB（NF-κB）translocation to the nuclei in cells treated with IL-1β.In addition,we assessed the transcriptional activity of NF-κB using an electrophoretic mobility shift assay（EMSA）.Finally,we evaluated the effect of resveratrol on IL-1β-induced inhibition of glucose-stimulated insulin secretion in freshly isolated rat pancreatic islets.Results：Resveratrol significantly suppressed IL-1β-induced NO production,a finding that correlated well with reduced levels of iNOS mRNA and protein.The molecular mechanism by which resveratrol inhibited iNOS gene expression appeared to involve increased PPAR-γactivity,which resulted in the inhibition of NF-κB activation.Further analysis showed that resveratrol could prevent IL-1β-induced inhibition of glucose-stimulated insulin secretion in rat islets.Conclusion：In this study,we demonstrated that resveratrol could protect against pancreaticβ-cell dysfunction caused by IL-1β.

Targeting PPARαin low ambient temperature exposure-induced cardiac dysfunction and remodeling

The present study demonstrates that the down-regulation of peroxisome proliferator-activated receptor-α(PPARα)results in chronic low ambient temperature(LT)exposure-induced cardiac dysfunction and remodeling,emphasizing the therapeutic potential of PPARαactivation strategies(e.g.,fenofibrate treatment)in LT-associated cardiac injury.

Effectiveness of sub-maximal intermittent exercise on muscle glycogen depletion, PGC-1<i>α</i>and PDK-4 gene expression

Several metabolic gene expressions are regulated in concert with muscle glycogen status. We hypothesized that intermittent exercise performed at high but sub-maximal intensities with long recovery periods would induce a low glycogen state that would stimul- ate peroxisome proliferator-activated receptor-γ coa- ctivator-1α (PGC1-α) and pyruvate dehydrogenase kinase-4 (PDK-4) gene expression in muscle. Nine young human subjects performed two intermittent exercise sessions. One session consisted of 60 s cycling bouts at VO2max (IE100%), and the other session consisted of 75 s cycling bouts at 80% VO2max (IE80%). Twelve bouts of exercise were completed in both sessions with a 4 min rest between each bout. Muscle specimens were obtained at pre-exercise and immediately, 1.5 h and 3 h post-exercise. Muscle gly- cogen was significantly decreased after both sessions (IE100%, 94.1 ± 5.8 to 38.7 ± 5.5 mmol/kg w.w.;IE80%, 94.6 ± 9.1 to 53.3 ± 4.8 mmol/kg w.w.;both P α and PDK- 4 mRNA expression were significantly increased after exercise in both IE100% and IE80% (PGC-1α: ~3.7 and ~2.9-fold, respectively;PDK-4: ~11.1 and ~3.5-fold, respectively;all P 100% than in IE80% (P a and PDK-4 mRNA expression, suggesting that increasing exercise intensity contributes to muscle glycogen depletion and PDK-4 mRNA expression in human skeletal muscle.

Forensic Significance of Messenger RNA and Protein Expression of Genes Downstream of Hypoxia Inducible Factor 2 in Myocardial Tissue for Death Discrimination

Background: As a heterodimeric transcription factor, hypoxia-inducible factor 2 alpha subunit (HIF2A), is an important member of the HIF family. It plays a significant role in the hypoxia adaptation process by regulating the different types of downstream transcription factors and auxiliary regulatory factors. HIF2A-related factors are believed to participate in the progression of myocardial injury or myocardial ischemia, support the protection of ischemic myocardium, and provide guiding significance for the diagnosis and discrimination of sudden cardiac death in forensic pathology. Aim and Objectives: This study aimed to explore the discriminability and applicability of HIF2A-related factors in myocardial infarction cases compared with other causes of death, provide further insights for the forensic diagnosis of heart failure (HF) cases with myocardial infarction, and support the clinical treatment of patients with HF after myocardial infarction. Materials and Methods: The relative expression levels of HIF2A, amphiregulin (AREG), potassium large conductance calcium-activated channel subfamily M β1 (KCNMB1), peroxisome proliferator-activated receptor α (PPARA), vascular endothelial growth factor (VEGF), and VEGFR2 messenger RNAs (mRNAs) in myocardial tissue samples were performed using quantitative reverse transcriptase-polymerase chain reaction. A partial least squares-discriminant analysis model was constructed to select the indicators with better identification effects for myocardial infarction cases. The protein levels of HIF2A, AREG, KCNMB1, and PPARA were further detected by immunohistochemistry. The forensic autopsy cases (27 cases in total, postmortem interval <72 h) included seven cases of acute myocardial infarction and ten cases of myocardial ischemia. There were ten cases in the control group, including four cases of traffic injury, one case of injury by fall from height, and five cases of blunt force injury. Results: Characteristic results were observed in the myocardial ischemia/infarction samples. Compared with the control group, the relative mRNA expression levels of AREG, KCNMB1, and PPARA were significantly increased during the progression of myocardial ischemia, but this was not observed for HIF2A, VEGF, or VEGFR2 mRNA. Immunohistochemistry assays further verified the expression levels of the related factors at the protein level, and H and E staining showed signs of angiogenesis and inflammation in the ischemia/infarction group. Conclusions: By controlling the expression of downstream target genes (AREG, KCNMB1, and PPARA) during myocardial cell hypoxia adaptation, HIF2A has a potential significance in the diagnosis of myocardial infarction in forensic medicine. We believe that HIF2A, AREG, KCNMB1, and PPARA can be used as molecular pathological biomarkers for the discrimination of causes of death in myocardial infarction cases.

Effects of Mitochondrial Dysfunction via AMPK/PGC-1α Signal Pathway on Pathogenic Mechanism of Diabetic Peripheral Neuropathy and the Protective Effects of Chinese Medicine

Diabetic peripheral neuropathy(DPN) is a progressive neurodegenerative disease of peripheral nervous system with high energy requirement. The adenosine monophosphate-activated protein kinase(AMPK)/peroxisome proliferator-activated receptor-γ coactivator 1α(PGC-1α) axis plays a key role in regulating mitochondrial energy metabolism. Increasing preclinical evidences have shown that inhibition of AMPK/PGC-1α pathway leading to mitochondrial dysfunction in neurons or Schwann cells contributes to neuron apoptosis, distal axonopathy and nerve demyelination in DPN. Some Chinese medicine formulae or extracts from herbs may have potential neuroprotective effects on DPN via activating AMPK/PGC-1α pathway and improving mitochondrial function.

Danqi Tablet(丹七片)Regulates Energy Metabolism in Ischemic Heart Rat Model through AMPK/SIRT1-PGC-1α Pathway

Objective To investigate the cardioprotective effect of Danqi Tablet(DQT,丹七片)on ischemic heart model rats and the regulative effect on energy metabolism through peroxisome proliferator-activated receptor-γcoactivator-1α(PGC-1α).Methods Rat ischemic heart model was induced by ligation of left anterior descending coronary artery.Totally 40 Sprague-Dawley rats were randomly divided into sham group,model group,DQT group(1.5 mg/kg daily)and trimetazidine(TMZ)group(6.3 mg/kg daily)according to a random number table,10 rats in each group.Twenty-eight days after continuous administration,cardiac function was assessed by echocardiography and the structures of myocardial cells were observed by hematoxylin-eosin staining.The level of adenosine triphosphate(ATP)in myocardial cells was measured by ATP assay kit.Expressions level of key transcriptional regulators,including PGC-1α,Sirtuin 1(SIRT1),AMP-activated protein kinase(AMPK),and downstream targets of PGC-1α,such as mitofusin 1(MFN1),mitofusin 2(MFN2)and superoxide dismutase 2(SOD2)were measured by Western blot.Expression level of PGC-1αwas examined by immunohistochemical staining.Results The rat ischemic heart model was successfully induced and the heart function in model group was compromised.Compared with the model group,DQT exerted cardioprotective effects,up-regulated the ATP production in myocardial cells and inhibited the infiltration of inflammatory cells in the margin area of infarction of the myocardial tissues(P<0.01).The expressions of PGC-1α,SIRT1 and AMPK were increased in the DQT group(all P<0.05).Furthermore,the downstream targets,including MFN1,MFN2 and SOD2 were up-regulated(P<0.05 or P<0.01).Compared with the TMZ group,the expression levels of PGC-1α,MFN1 and SOD2 were increased by DQT treatment(P<0.05 or P<0.01).Conclusion DQT regulated energy metabolism in rats with ischemic heart model through AMPK/SIRT1-PGC-1αpathway.PGC-1αmight serve as a promising target in the treatment of ischemic heart disease.

Sirtuins Function as the Modulators in Aging-related Diseases in Common or Respectively

INTRODUCTIONAccording to the demographics, the world population over 60 years will double from 605 million to 2 billion people between 2000 and 2050. Aging is a complex process in which the organism and its ability to respond to external stresses become progressive decline.