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1.
J Cell Physiol ; 233(10): 6613-6620, 2018 10.
Article in English | MEDLINE | ID: mdl-29215742

ABSTRACT

We explored the effects of RNA interference-mediated silencing of TLR4 gene on expressions of adipocytokines in obstructive sleep apnea hyponea syndrome (OSAS) with hypertension in a rat model. Systolic blood pressure of caudal artery and physiological changes were observed when establishing rat models of OSAS with hypertension. Mature rat adipocytes were induced from separated and cultured primary rat adipocytes. To transfect rat mature adipocytes, TLR4 siRNA group and negative control (NC) siRNA group were established. Expressions of TLR4 mRNA of adipocytes were examined after silenced by siRNA by quantitative real-time polymerase chain reaction (qRT-PCR). By enzyme-linked immunosorbent assay (ELISA), expressions of inflammatory cytokines, and adipocytokines of adipocytes were detected. Blood pressure in rat caudal artery was higher in the intermittent hypoxia group than that of the blank control group by 29.87 mmHg, and cardiocytes in the former group showed physiological changes, which indicated successful establishment of rat models of OSAS with hypertension. Red particles could be seen in mature rat adipocytes when stained with Oil Red O. Transfection of TLR4 mRNA was significantly suppressed in the TLR4 siRNA group, which didn't happen in the untransfected control group. Rats in the TLR4 siRNA group had significantly reduced expressions of such inflammatory cytokines as interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-α (TNF-α) and such adipocytokines as visfatin, adiponectin (ADN), and leptin than those in the untransfected control group. RNA interference-mediated silencing of TLR4 gene could regulate occurrence and development of OSAS with hypertension in rats by downregulating expressions of adipocytokines.


Subject(s)
Adipokines/genetics , Hypertension/genetics , Sleep Apnea, Obstructive/genetics , Toll-Like Receptor 4/genetics , Adipocytes/metabolism , Adiponectin/genetics , Animals , Cytokines/genetics , Disease Models, Animal , Gene Expression Regulation/genetics , Humans , Hypertension/complications , Hypertension/pathology , Interleukin-6/genetics , Interleukin-8/genetics , Leptin/genetics , Male , Nicotinamide Phosphoribosyltransferase/genetics , RNA, Small Interfering/genetics , Rats , Sleep Apnea, Obstructive/complications , Sleep Apnea, Obstructive/pathology , Toll-Like Receptor 4/antagonists & inhibitors , Tumor Necrosis Factor-alpha/genetics
2.
Mol Med Rep ; 16(5): 6405-6411, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28901399

ABSTRACT

Macrophage polarization is flexible, and involves in different signaling pathways and various transcription factors. Suppressor of cytokine signaling (SOCS) is an important inhibitor of cytokine signaling pathways and also a key physiological regulator for natural and acquired immunity systems. Following transfection of SOCS1 short hairpin (sh)RNA into mouse macrophage cells, reverse transcription­quantitative polymerase chain reaction demonstrated that the mRNA levels of Janus kinase (JAK)1 and signal transducer and activator of transcription (STAT)1 increased significantly. In addition, western blotting indicated that JAK1, STAT1 and p­STAT1 expression was significantly enhanced. Fludarabine can inhibit phosphorylation of STAT1 and SOCS1 expression. When fludarabine was added and SOCS1 shRNA was transfected, the inhibition of fludarabine was weakened, and p­STAT1 expression was upregulated. Flow cytometry detection indicated that, following the downregulation of SOCS1 expression, M1­type cells significantly increased, but the proportion of M2­type cells did not change significantly. Fludarabine can reduce the effect of SOCS1 shRNA on promoting M1­type cell polarization, and macrophages can polarize into both M1 and M2 phenotypes. Further ELISA results presented that, when downregulating SOCS1 expression, interleukin (IL)­4 and IL­10 expression was both downregulated, and tumor necrosis factor (TNF)­α and interferon (IFN)­Î³ expression was significantly upregulated. When adding fludarabine or injecting with the traditional Chinese medicine Xuebijing, IL­4 and IL­10 expression was both significantly upregulated, and TNF­α and IFN­Î³ expression was significantly downregulated. When adding fludarabine and downregulating SOCS1, IL­4, IL­10, TNF­α and IFN­Î³ expression presented no significant changes. The above results indicated that, when SOCS1 expression is downregulated, it will activate the JAK1/STAT1 pathway, and thereby promote the polarization of macrophages into M1 type. The findings are of great importance for understanding occurrence, development and treatment of various immune­related diseases.


Subject(s)
Janus Kinase 1/immunology , Macrophages, Peritoneal/immunology , STAT1 Transcription Factor/immunology , Signal Transduction/immunology , Suppressor of Cytokine Signaling 1 Protein/immunology , Animals , Anti-Inflammatory Agents/pharmacology , Cell Differentiation , Drugs, Chinese Herbal/pharmacology , Enzyme Inhibitors/pharmacology , Gene Expression Regulation , Interferon-gamma/genetics , Interferon-gamma/immunology , Interleukin-10/genetics , Interleukin-10/immunology , Interleukin-4/genetics , Interleukin-4/immunology , Janus Kinase 1/genetics , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/drug effects , Mice , Phosphorylation , Primary Cell Culture , RNA, Small Interfering/genetics , RNA, Small Interfering/immunology , STAT1 Transcription Factor/agonists , STAT1 Transcription Factor/genetics , Suppressor of Cytokine Signaling 1 Protein/antagonists & inhibitors , Suppressor of Cytokine Signaling 1 Protein/genetics , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/immunology , Vidarabine/analogs & derivatives , Vidarabine/antagonists & inhibitors , Vidarabine/pharmacology
3.
J Cell Biochem ; 118(12): 4230-4239, 2017 12.
Article in English | MEDLINE | ID: mdl-28419526

ABSTRACT

Sepsis is one of the most challenging health problems worldwide. Our previous study showed that chronic schistosoma japonica (SJ) infection might increase serum anti-inflammatory factors to play a protective role, thus improving the survival rate of septic mice. Further research revealed that SJ infection promoted J774A.1 macrophage differentiation into M2 macrophages; suppressed LPS-induced activation of M1 macrophages; up-regulated CD163, IL-10, and TGF-ß1 expression; inhibited TNF-α and iNOS expression; and blocked the effect of LPS-promoted TNF-α and iNOS expression. Furthermore, adoptive transfer of ex vivo programed M2 macrophages significantly increased the survival rate of septic mice. In vitro studies suggested that soluble egg antigen (SEA) from SJ played the same role as worm infection but had no impact on M1 macrophages. SEA reduced LPS-induced TNF-α and iNOS expression, decreased the inhibitory effect of LPS on IL-10 and TGF-ß1 expression, increased STAT6 phosphorylation, and up-regulated PI3K and Akt expression but inhibited SOCS1 expression. When PI3K inhibitors were added, SEA-induced expression of CD163, IL-10, and arg1 might be reduced. Therefore, worm infection has a protective effect in septic mice in which SEA may play a key role via the STAT6 and PI3K pathways. This finding may provide a favorable solution for the treatment of sepsis, especially early cases. J. Cell. Biochem. 118: 4230-4239, 2017. © 2017 Wiley Periodicals, Inc.


Subject(s)
Antigens, Helminth/immunology , Cytokines , Macrophages/metabolism , Schistosomiasis japonica/complications , Sepsis/complications , Signal Transduction , Animals , Macrophages/immunology , Mice , Nitric Oxide Synthase Type II , Phosphatidylinositol 3-Kinases/metabolism , STAT6 Transcription Factor/metabolism , Schistosomiasis japonica/immunology , Schistosomiasis japonica/metabolism , Sepsis/mortality , Survival Rate
4.
Comput Biol Chem ; 65: 16-20, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27694041

ABSTRACT

OBJECTIVE: This paper aimed to investigate ego modules for TGFß3-induced chondrogenesis in mesenchymal stem cells (MSCs) using ego network algorithm. METHODS: The ego network algorithm comprised three parts, extracting differential expression network (DEN) based on gene expression data and protein-protein interaction (PPI) data; exploring ego genes by reweighting DEN; and searching ego modules by ego gene expansions. Subsequently, permutation test was carried out to evaluate the statistical significance of the ego modules. Finally, pathway enrichment analysis was conducted to investigate ego pathways enriched by the ego modules. RESULTS: A total of 15 ego genes were obtained from the DEN, such as PSMA4, HNRNPM and WDR77. Starting with each ego genes, 15 candidate modules were gained. When setting the thresholds of the area under the receiver operating characteristics curve (AUC) ≥0.9 and gene size ≥4, three ego modules (Module 3, Module 8 and Module 14) were identified, and all of them had statistical significances between normal and TGFß3-induced chondrogenesis in MSCs. By mapping module genes to confirmed pathway database, their ego pathways were detected, Cdc20:Phospho-APC/C mediated degradation of Cyclin A for Module 3, Mitotic G1-G1/S phases for Module 8, and mRNA Splicing for Module 14. CONCLUSIONS: We have successfully identified three ego modules, evaluated their statistical significances and investigated their functional enriched ego pathways. The findings might provide potential biomarkers and give great insights to reveal molecular mechanism underlying this process.


Subject(s)
Chondrogenesis/physiology , Mesenchymal Stem Cells/cytology , Transforming Growth Factor beta3/physiology , Gene Expression Profiling , Humans
5.
Innate Immun ; 22(6): 419-32, 2016 08.
Article in English | MEDLINE | ID: mdl-27312706

ABSTRACT

Sepsis is a serious clinical condition of excessive systemic immune response to microbial infection. The pro-inflammatory stage of sepsis is generally launched by innate cells such as macrophages. They release inflammatory cytokines, activate other immune cells and cause severe tissue/organ damage. In this study, we have revealed that recombinant Trichinella spiralis (TS) excretory-secretory protein (rTsP53) exhibited anti-inflammatory properties and rescued mice from LPS-induced endotoxemia, which is a common model for sepsis study, potentially through the induction of M2 macrophages. rTsP53 treatment significantly decreased inflammatory cytokines (IL-6, IFN-γ and TNF-α) and increased IL-4, IL-10, IL-13 and TGF-ß secretion, both in circulation and in tissues. rTsP53 also induced the activation and infiltration of F4/80(+)CD163(+) macrophages to inflammatory tissues, increased M2 macrophage-related Arg1 and Fizz1 expression, and decreased M1 macrophage-related iNOS expression. PCR array showed that rTsP53 activated several genes that involve the survival of macrophages and also anti-inflammatory genes such as SOCS3. Together, our results show that rTsP53 activates M2 macrophages, which has strong anti-inflammatory potential to prevent LPS-induced lethal sepsis.


Subject(s)
Anti-Inflammatory Agents/metabolism , Antigens, Helminth/metabolism , Endotoxemia/immunology , Helminth Proteins/metabolism , Macrophages/immunology , Trichinella spiralis/immunology , Trichinellosis/immunology , Animals , Anti-Inflammatory Agents/immunology , Antigens, Helminth/immunology , Cell Movement , Cells, Cultured , Cytokines/metabolism , Disease Models, Animal , Helminth Proteins/immunology , Inflammation Mediators/metabolism , Lipopolysaccharides/immunology , Macrophage Activation , Macrophages/parasitology , Male , Mice , Mice, Inbred BALB C , Suppressor of Cytokine Signaling 3 Protein/genetics , Suppressor of Cytokine Signaling 3 Protein/metabolism
6.
Mar Drugs ; 13(9): 5593-605, 2015 Aug 28.
Article in English | MEDLINE | ID: mdl-26343688

ABSTRACT

Micrometam C is a core of novel marine compound isolated from the mangrove associates Micromelum falcatum. In this study, we investigated the protective effects of micrometam C in inflammation models in the transgenic zebrafish line Tg (corola: eGFP) and RAW264.7 macrophages. We found that micrometam C significantly suppressed the migration of immune cells in tail-cutting-induced inflammation in transgenic zebrafish and reduced lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) in both zebrafish and macrophages. In addition, micrometam C also restored LPS-induced reduction of endogenous antioxidants, such as catalase (CAT), glutathione (GSH) and superoxide dismutase (SOD). The protective effects of micrometam C were in parallel to its inhibition of NADPH oxidase and nuclear factor-kappa-binding (NF-κB) activity. Thus, the present results demonstrate that micrometam C protects against LPS-induced inflammation possibly through its antioxidant property.


Subject(s)
Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Coumaric Acids/chemistry , Coumaric Acids/pharmacology , Inflammation/drug therapy , Animals , Antioxidants , Cell Line , Gene Expression Regulation/drug effects , Lipopolysaccharides/toxicity , Macrophages , Mice , Molecular Structure , NADPH Oxidases/metabolism , NF-kappa B/genetics , NF-kappa B/metabolism , Oxidative Stress , Respiratory Burst , Tail , Zebrafish
7.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue ; 24(12): 713-6, 2012 Dec.
Article in Chinese | MEDLINE | ID: mdl-23168197

ABSTRACT

OBJECTIVE: To improve cost-efficiency, discriminant functions in stepwise method was founded for the differential diagnosis of angina pectoris by detecting the serum level of high-sensitivity C-reactive protein (hs-CRP), macrophage migration inhibitory factor (MIF), interleukin-4 (IL-4) and interleukin-10 (IL-10) in patients with stable angina pectoris (SAP) and unstable angina pectoris (UAP). METHODS: Thirty-nine SAP patients and 47 UAP patients were enrolled into the study, while 39 healthy volunteers were enrolled into the controlled group forming the entire set of training samples. The serum levels of hs-CRP, MIF, IL-4 and IL-10 were measured by enzyme linked immunosorbent assay (ELISA). Data was analyzed by software to define discriminant functions in the ways of "entering" and "stepwise". Both functions were evaluated by the results of validation. RESULTS: By the way of "enter independent together", the following discriminant functions were defined based on the data of training samples' age, hs-CRP, MIF, IL-4, IL-10: healthy control group =-129.858 + 2.869×age -2.451×hs-CRP + 1.393×MIF + 6.001×IL-4 + 4.848×IL-10; SAP group=-161.037 + 2.896×age-2.022×hs-CRP + 1.662×MIF + 6.703×IL-4 + 6.287×IL-10; UAP group=-199.087 + 2.468×age-1.440×hs-CRP + 3.404×MIF-13.875×IL-4 + 7.752×IL-10. Retrospective validation showed 4.8% of total miss-grouping, while cross-validation showed 5.6% of total miss-grouping. By the way of "stepwise", the above data was screened by software and training samples' age, MIF and IL-10 were suggested to define the following functions: healthy control group = - 125.218 + 2.659 × age + 0.599×MIF + 5.040 × IL-10; SAP group=-157.864 + 2.721×age + 1.008×MIF + 6.468×IL-10; UAP group=- 197.327 + 2.360×age + 2.932×MIF + 7.640×IL-10. Both retrospective and cross validation showed 6.4% of total miss-grouping. Both sets of discriminant functions had the same efficiency (100%) for differential diagnosis of SAP and UAP. CONCLUSION: The discriminant functions based on samples' age, MIF and IL-10, which were screened and suggested by stepwise method, may contribute to the differential diagnosis of atypical SAP and UAP, and therefore demonstrate better cost-efficiency.


Subject(s)
Angina Pectoris/blood , Angina Pectoris/diagnosis , C-Reactive Protein/metabolism , Interleukin-10/blood , Aged , Angina Pectoris/classification , Case-Control Studies , Discriminant Analysis , Female , Humans , Inflammation , Interleukin-4/blood , Intramolecular Oxidoreductases/blood , Macrophage Migration-Inhibitory Factors/blood , Male , Middle Aged , Retrospective Studies
8.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue ; 24(3): 154-7, 2012 Mar.
Article in Chinese | MEDLINE | ID: mdl-22685717

ABSTRACT

OBJECTIVE: To evaluate the effects of microRNA-155 (miR-155) on liver injury in mice with sepsis. METHODS: One hundred and twenty BALB/c mice were randomly divided into two groups of equal number according to random number table. Sepsis was induced by intraperitoneal injection of lipopolysaccharide (LPS,20 mg/kg). The mice were sacrificed at the time-points of 0, 2, 6, 12, 24, 48 hours. Blood and liver tissue were collected, and the levels of tumor necrosis factor- α (TNF- α ), interleukin (IL-6, IL-10) in serum and liver homogenate and alanine transaminase (ALT) in serum were determined by enzyme linked immunosorbent assay(ELISA). The injury of liver tissue was evaluated by histopathology. The expression of miR-155 in liver tissue was assessed by fluorescent quantitation reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The levels of TNF- α , IL-6 and IL-10 in serum and liver homogenate of septic mice increased with passage of time, and then the levels of TNF-α and IL-6 lowered after reaching the peak value, but remained higher than that of control group.TNF-α (ng/L) reached the peak value at 2 hours post-LPS-injection (serum: 1538.46 ± 102.12 vs. 64.52 ± 18.44,liver homogenate: 255.26 ± 41.23 vs. 60.21 + 13.55, both P<0.05). The level of IL-6 (µg/L) reached the peak value at 6 hours post-LPS-injection (serum: 875.33 ± 102.37 vs. 153.72 ± 20.67, liver homogenate: 9.22 + 0.82 vs. 3.35 ±0.36, both P<0.05), and that of IL-10 (ng/L) reached the peak value at 48 hours post-LPS-injection (serum: 520.13 ± 88.52 vs. 23.43 3.01, liver homogenate: 260.12 + 50.38 vs. 16.37 ± 3.71, both P<0.05). There were significant differences in above indexes between septic and control group (all P<0.05). The serum level of ALT (U/L) rose with passage of time, reaching the peak value at 48 hours post-LPS-injection (603.26 + 70.21 vs. 45.84 + 5.64, P<0.05). The values showed significant differences between septic and control group (P<0.05). A large number of leucocytic infiltration was found in liver. Hepatic tissue showed architectural distortion. Hepatocyte vacuolation and nodular necrosis were obvious at 12 hours post-LPS-injection. Relative expression of miR-155 was found to be increased at 2 hours post-LPS-injection, reaching its peak value at 12 hours post-LPS-injection [(72.96 ± 9.34)-fold of control group, P<0.05]. CONCLUSION: The increase in miR-155 expression might play an important role in the mechanism of liver injury during sepsis.


Subject(s)
Liver/metabolism , MicroRNAs/metabolism , Sepsis/metabolism , Animals , Liver/pathology , Male , Mice , Mice, Inbred BALB C , Sepsis/pathology
9.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue ; 23(5): 290-3, 2011 May.
Article in Chinese | MEDLINE | ID: mdl-21549067

ABSTRACT

OBJECTIVE: To preliminarily study the protective effect of chronic schistosoma japonica (SJ) infestation against sepsis in mice and its mechanism. METHODS: BALB/c male mice were used, and the experiment was divided into three parts. Experiment 1: chronic SJ infestation model was reproduced by SJ cercaria inoculation through abdominal skin for 8 weeks. Twenty mice were randomly grouped into normal group (n=10) and SJ group (n=10). The levels of interleukins (IL-4, IL-10),tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in serum were detected by enzyme linked immunosorbent assay (ELISA). Real-time polymerase chain reaction (PCR) was employed to detect the levels of IL-10 mRNA and TNF-αmRNA in abdominal macrophages. This experiment was meant to evaluate immune state in mice with chronic SJ infestation. Experiment 2: lipopolysaccharide (LPS) was intraperitoneally injected to reproduce sepsis model. Thirty mice were randomly grouped into LPS group (n=15) and SJ-LPS group (n=15). The levels of cytokines were determined by ELISA at 0, 24, 48 and 72 hours after LPS injection. This experiment was meant to detect the effect of chronic SJ infestation in mice during the septic process. Experiment 3: two types of sepsis model were reproduced by cecal ligation and puncture (CLP) and LPS injection, respectively. The survival rate of mice with chronic SJ infestation in 72 hours in either type of sepsis was evaluated. RESULTS: Experiment 1: compared with normal group [IL-4 (56.32±8.66) ng/L, IL-10 (48.17±7.23) ng/L], chronic SJ infestation showed an increase in serum IL-4 [(151.35±12.24) ng/L] and IL-10 [(133.22±11.09) ng/L, both P<0.05]. Chronic SJ infestation also resulted in an increase in IL-10 mRNA expression (SJ group 4.46±1.82, normal group 1.52±0.60) and inhibited TNF-α mRNA expression (SJ group 1.61±0.93, normal group 2.32±1.03) in abdominal macrophages (both P<0.05), indicating that macrophages could be differentiated into alternative activated macrophages. Experiments 2 and 3 showed that the levels of serum IL-4 and IL-10 were increased at 0 hour after LPS injection, and then gradually decreased in SJ-LPS group, but the levels were still higher than those in LPS group at 72 hours [IL-4 (ng/L): 92.2±7.6 vs. 41.5±4.5; IL-10 (ng/L): 92.1±7.8 vs. 35.6±4.0, both P<0.05]; the levels of TNF-α and IFN-γ were increased at 24 hours, and then decreased in SJ-LPS group, and the levels were lower than those in LPS group at 72 hours [TNF-α (ng/L): 82.9±5.6 vs. 91.5±5.2; IFN-γ (ng/L): 44.1±4.8 vs. 52.6±4.0, both P<0.05]. Therefore, chronic SJ infestation could improve the survival rate of mice with sepsis induced by CLP or LPS (CLP: 80% vs. 20%, LPS: 70% vs. 30%, both P<0.05). CONCLUSION: Chronic SJ infestation could elevate anti-inflammatory factors in septic mice, thus ameliorating the survival rate, so it has protective effect on mice with sepsis.


Subject(s)
Schistosomiasis japonica/immunology , Schistosomiasis japonica/metabolism , Sepsis/immunology , Animals , Interleukin-10/metabolism , Interleukin-4/metabolism , Male , Mice , Mice, Inbred BALB C , Schistosoma japonicum/immunology , Sepsis/mortality , Survival Rate , Tumor Necrosis Factor-alpha/metabolism
10.
Zhongguo Wei Zhong Bing Ji Jiu Yi Xue ; 22(5): 259-62, 2010 May.
Article in Chinese | MEDLINE | ID: mdl-20519071

ABSTRACT

OBJECTIVE: To identify the suppressor of cytokine signaling-1 (SOCS-1) of rat from the amplified gene with the help of bioinformatics to predict the deduced protein's structure and function in order to lay the foundation for further theoretical study. METHODS: The full-length rat SOCS-1 gene was amplified and identified from the GeneBank Nucleotide database, and the corresponding structure and function of its deduced protein was predicted by the bioinformatics analyzing tools online and the complicated bioinformatics software package Vector NTI suite 8.0, meanwhile the molecular cladogram was reconstructed. RESULTS: Two sequences were obtained by polymerase chain reaction (PCR) amplification of different SOCS-1 gene. The gene was comprised of 639 base pairs in the length, deduced 212 amino acids (aa), contained a SOCS box (aa172-aa208), a SH2 domain (aa80-aa155) and a nuclear localization sequence (aa160-aa174). The primary structure contained two linear B cell epitopes, all of them were on the surface of the protein and far away from the spatial structure. CONCLUSION: SOCS-1 gene has a polymorphism, its conservative SH2 region and SOCS box are related to its inhibitory effect on the signal transduction pathway. The nucleic localization sequence may affect other nuclear transduction factors. The B cell linear epitopes may be a candidate of immunodiagnosis with promising prospects.


Subject(s)
Polymorphism, Genetic , Suppressor of Cytokine Signaling Proteins/genetics , Amino Acid Sequence , Animals , Base Sequence , Computational Biology , Male , Molecular Sequence Data , Rats , Rats, Sprague-Dawley , Sequence Analysis, DNA , Suppressor of Cytokine Signaling 1 Protein
11.
Clin Exp Pharmacol Physiol ; 37(2): 156-61, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19566839

ABSTRACT

1. Rosiglitazone is widely used in the treatment of Type 2 diabetes. However, in recent years it has become evident that the therapeutic effects of peroxisome proliferator-activated receptor gamma ligands reach far beyond their use as insulin sensitizers. Recently, the ability of rosiglitazone pretreatment to induce cardioprotection following ischaemia-reperfusion (I/R) has been well documented; however, the protective mechanisms have not been elucidated. In the present study, examined the role of the phosphatidylinositol 3-kinase (PI3-K)/Akt signalling pathway in rosiglitazone cardioprotection following I/R injury. 2. Mice were pretreated with 3 mg/kg per day rosiglitazone for 14 days before hearts were subjected to ischaemia (30 min) and reperfusion (2 h). Wortmannin (1.4 mg/kg, i.p.), an inhibitor of PI3-K, was administered 10 min prior to myocardial I/R. Then, activation of the PI3-K/Akt/glycogen synthase kinase (GSK)-3alpha signalling pathway was examined. The effects of PI3-K inhibition on rosiglitazone-induced cardioprotection were also evaluated. 3. Compared with control rats, the ratio of infarct size to ischaemic area (area at risk) and the occurrence of sustained ventricular fibrillation in rosiglitazone-pretreated rats was significantly reduced (P < 0.05). Rosiglitazone pretreatment attenuated cardiac apoptosis, as assessed by ELISA to determine cardiomyocyte DNA fragmentation. Rosiglitazone pretreatment significantly increased levels of phosphorylated (p-) Akt and p-GSK-3alpha in the rat myocardium. Pharmacological inhibition of PI3-K by wortmannin markedly abolished the cardioprotection induced by rosiglitazone. 4. These results indicate that rosiglitazone-induced cardioprotection in I/R injury is mediated via a PI3-K/Akt/GSK-3alpha-dependent pathway. The data also suggest that modulation of PI3-K/Akt/GSK-3alpha-dependent signalling pathways may be a viable strategy to reduce myocardial I/R injury.


Subject(s)
Myocardial Reperfusion Injury/prevention & control , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Thiazolidinediones/therapeutic use , Androstadienes/pharmacology , Animals , Blood Glucose/drug effects , Glycogen Synthase Kinase 3/metabolism , Male , Mice , Myocardial Infarction/enzymology , Myocardial Infarction/prevention & control , Myocardial Reperfusion Injury/enzymology , PPAR gamma/agonists , Rats , Rosiglitazone , Ventricular Fibrillation/enzymology , Ventricular Fibrillation/prevention & control , Wortmannin
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