Role of PPARα/PGC-1α in doxorubicin induced mouse dilated cardio-myopathy

AIM: To investigate the changes of peroxisome proliferator-activated receptors (PPAR)α/peroxisome proliferator activated receptor coactivator 1 alpha (PGC-1α) in doxorubicin (DOX) induced dilated cardiomyopathy (DCM) and its effect on the energy metabolism and myocardial function in mice. METHODS: Forty mice were randomly divided into 4 groups: control group, DOX group, PPARα inhibitor group and PPARα agonist group. The DCM model was established by injection of DOX. The protein levels of PPARα/PGC-1α were detected. The PPARα inhibitor and PPARα agonist were used 2 weeks beforeinjection of DOX. The contents of adenine acid and phosphocreatine (Pcr) in the mitochondria were measured by high-performance liquid chromatography (HPLC). The ANT activity was analyzed by the atractyloside-inhibitor stop technique. The changes of the echocardiography and hemodynamics were also observed. RESULTS: DOX induced DCM model was successfully established. The protein levels of PPARα and PGC-1α in control group were significantly higher than those in DOX group (P<0.05). Both of the high-energy phosphate contents and the transport activity of ANT were decreased in DOX group (P<0.05), and the hemodynamic parameters were disordered (P<0.01). Compared with DOX group, PPARα inhibitor pre-treatment significantly reduced the PPARα/PGC-1α expression. Meanwhile, high-energy phosphate contents in the mitochondria and the ANT transport activity of the mitochondria decreased, as well as the left ventricular function (P<0.05). On the other hand, PPARα agonist significantly increased the expression of PPARα and PGC-1α, and improved the transport activity of ANT. In addition, the hemodynamic parameters were ameliorated, but the high-energy phosphate contents of the mitochondria did not significantly change. CONCLUSION: PPARα/PGC-1α plays an important role in the regulation of ANT transport activity in dilated cardiomyopathy induced by DOX, and the activation of PPARα/PGC-1α has protective effects on the DCM induced by DOX.     

Effect of rosiglitazone on expression of AQP1, VEGF-A and COX-2 in human peritoneal microvascular endothelial cells

AIM: To investigate the effect of rosiglitazone on the expression of aquaporin-1 (AQP1), vascular endothelial growth factor-A (VEGF-A) and cyclooxygenase-2 (COX-2) in human peritoneal microvascular endothelial cells.METHODS: Cultured peritoneal microvascular endothelial cells were divided into 4 groups. The morphological changes of the cells were observed under inverted microscope. The protein expression of AQP1, VEGF-A and COX-2 in human peritoneal microvascular endothelial cells was determined by Western blotting. The mRNA expression of AQP1, VEGF-A and COX-2 in the cells was measured by real-time PCR. RESULTS: Rosiglitazone stimulated the proliferation of the cells. Rosiglitazone up-regulated the expression of AQP1, and down-regulated the expression of VEGF-2 and COX-2 at mRNA and protein levels in the cells. The PPAR-γ antagonist GW9662 partly inhibited the up-regulation of AQP1 expression by rosiglitazone (P<0.05), but had no obvious effect on the expression of VEGF-A and COX-2 (P>0.05). CONCLUSION: Rosiglitazone up-regulates the expression of AQP1 and down-regulates the expression of VEGF-A and COX-2 in human peritoneal microvascular endothelial cells, thus promoting water transportation and attenuating peritoneal fibrosis during peritoneal dialysis.     

Role of ghrelin in cell protection by up-regulating HSP70 through ERK1/2 signaling pathway in PC12 cells

AIM:To study the role of ghrelin in cell protection by up-regulating heat shock protein 70 (HSP70) and inhibiting apoptosis induced by oxidative stress through extracellular regulated protein kinases 1/2 (ERK1/2) signaling pathway in the PC12 cells. METHODS:Sodium nitoprusside (SNP) was used to induce oxidative stress injury in the PC12 cells. The cultured PC12 cells were divided into SNP-injured group (incubated with SNP at 0.5 mmol/L for 6, 12, 18 and 24 h), ghrelin pretreatment group (ghrelin at 100 nmol/L was given 30 min before adding SNP); HSP70 inhibitor group (quercetin at 10 μmol/L was added 60 min before ghrelin treatment), ERK inhibitor group (ERK 1/2 inhibitor PD98059 was added 60 min before ghrelin treatment) and control group (added same amount of culture medium only). The apoptotic rate was detected by flow cytometry. The protein expression was determined by Western blot and immunocytochemistry. RESULTS:Compared with control group, the apoptotic rate of PC12 cells in SNP-injured group was significantly increased (P<0.05). Compared with SNP-injured group, ghrelin (100 nmol/L) pretreatment significantly inhibited SNP-induced apoptosis of PC12 cells (P<0.05), and significantly up-regulated the protein expression of HSP70 (P<0.05). Time-effect analysis showed that ghrelin had the most significant effect at 18 h after SNP injury. Quercetin, an inhibitor of HSP 70, significantly reduced the anti-apoptotic effect of ghrelin (P<0.05). Ghrelin pretreatment promoted the phosphorylation of ERK1/2. ERK1/2 inhibitor PD98059 significantly inhibited the effects of ghrelin on up-regulation of HSP70 expression (P<0.05). CONCLUSION:Ghrelin upregulates the expression of HSP70 and inhibits the apoptosis in the PC12 cells induced by oxidative stress by promoting the phosphorylation of ERK1/2.     

Effects of resveratrol on cardiac dysfunction and ASMase-ceramide pathway in type 2 diabetic rats

AIM:To investigate the effects of resveratrol (RSV) on cardiac dysfunction and acid sphingomyelinase (ASMase)-ceramide pathway in diabetic rats. METHODS:Type 2 diabetes mellitus (T2DM) model was established by a high-fat diet combined with STZ intraperitoneac injection (30 mg/kg). SD rats (n=20) were randomly divided into control group, T2DM group; T2DM+RSV group (diabetic rats were given resveratrol at 100 mg·kg·d^-1 by intragastric administration for the treatment) and RSV group (some of control rats were selected to give the same dose of RSV for drug control group). The M-mode Doppler ultrasonography was performed to observe the changes of cardiac function and structure in the rats. The levels of serum glucose, lipid and superoxide dismutase (SOD) activity, malondialdehyde (MDA) content in heart tissues were measured. Oil red O staining and Sirius red staining were performed to observe lipid accumulation and cardiac fibrosis in heart tissues. The cardiac ceramide concentration in diabetic rats was analyzed by high-performance liquid chromatography. The protein expression of ASMase and peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α) in the hearts was determined by Western blot. RESULTS:Compared with the control group, the levels of fasting blood glucose, total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) were significantly elevated in T2DM group. The values of ±dp/dt_max, fractional shortening and ejection fraction were declined, and the left ventricle internal dimension at end-systole (LVIDs) and left ventricle internal at end-diastole (LVIDd) were increased. Furthermore, increased MDA content and more lipid accumulation were also observed in diabetic hearts, while the SOD activity, ATP content and PGC-1α expression were reduced in diabetic hearts. However, all these parameters were reversed by addition of RSV, concomitant with decreased ASMase expression and ceramide content. CONCLUSION:RSV dramatically alleviates diabetes-induced cardiac dysfunction and cardiac fibrosis, which may attribute to inhibition of ASMase-ceramide activation.     

Effect of FGFR1 expression knock-down on biological characteristics of infantile hemangioma endothelial cells

AIM: To study the effect of fibroblast growth factor receptor 1 (FGFR1) expression knock-down on the viability, apoptosis, invasion and migration of infantile hemangioma endothelial cells (HemECs). METHODS: FGFR1 was down-regulated by FGFR1 small interfering RNA (si-FGFR1) transfection. The viability of the cells was measured by CCK-8 assay. The apoptotic rate was analyzed by flow cytometry and the invasion and migration abilities were determined by Transwell assay. The protein levels of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and phosphorylated AKT (p-AKT) were examined by Western blot. RESULTS: Transfection of si-FGFR1 into HemECs had significant effects on inhibiting cell viability (P<0.05), promoting apoptosis (P<0.05), and decreasing cell invasion and migration abilities (P<0.05). The results of Western blot showed that knockdown of FGFR1 gene expression in the cells reduced the protein levels of PI3K and p-AKT (P<0.05), and had no significant effect on AKT protein level. CONCLUSION: Knock-down of FGFR1 expression changes the biological characteristics of endothelial cells in infantile hemangiomas by regulating PI3K/AKT signaling pathway.     

Effect of miR-19a on lipid catabolism in hepatocyte LO2

AIM: To observe the effect of microRNA-19a (miR-19a) on the lipid catabolism of hepatocyte LO2, and to explore the potential mechanism. METHODS: miR-19a was over-expressed or silenced by transfection of miR-19a mimics or miR-19a inhibitor into LO2 cells, then the mRNA level of miR-19a was detected by real-time PCR. The potential target of miR-19a was found by the method of bioinformatics through internet website. The effect of miR-19a on the 3' UTR of peroxisome proliferator-activated receptor α (PPARα) was measured by dual luciferase reporter assay, and the protein level of PPARα and its 2 major downstream rate-limiting enzymes involved in lipid catabolism, acyl-coenzyme a dehydrogenase (ACADM) and carnitine palmitoyltransferase 1A (CPT1A), were detected by Western blotting. Meanwhile, the effect of miR-19a on the generation of ketone body was measured by beta-hydroxybutyric acid (β-OHB) detection assay. RESULTS: The mRNA level of miR-19a was dramatically elevated by the transfection of miR-19a mimics, and sharply decreased by the transfection of miR-19a inhibitor (P<0.05). PPARα was found as a potential target of miR-19a, and dual luciferase reporter assay and Western blotting confirmed the regulatory effect of miR-19a on the expression of PPARα, with the protein level changes of ACADM and CPT1A. miR-19a mimics down-regulated, while miR-19a inhibitor up-regulated the concentration of β-OHB in LO2 cells (P<0.05). CONCLUSION: miR-19a regulates the lipid catabolism of hepatocytes by targeting the PPARα and its 2 downstream rate-limiting enzymes.     

Influence of Tangshenfang on diabetic liver injury and the expression of SIRT1 and PGC-1α in the liver tissue

AIM: To observe the effect of Tangshenfang (TS) on the liver protection and the levels of silent information regulator 1 (SIRT1) and peroxisom proliferator-activated receptor γ coactivator-1α (PGC-1α) in the liver tissue. METHODS: The rat model of diabetes mellitus (DM) was established by intravenous injection of streptozotocin (STZ;30 mg/kg) after having the high fat/high glucose diets for 1 month. The diabetic rats were randomly divided into DM group, DM with high-dose TS (TS^Hi) group, medium-dose TS (TS^Med) group and low-dose TS (TS^Low)group. The normal rats were served as control group. There were 8 rats in each group. After treatment with TS for 12 weeks, the serum biochemical indices including fasting blood glucose (FBG), triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested. Fasting insulin (FINS) was also detected by radioimmunoassay, and homeostatic model assessment for insulin resistance (HOMA-IR) was calculated. The serum levels of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) were measured by ELISA. The activity of SOD and content of MDA in the liver tissues were measured by the methods of hydroxylamine and thiobarbituric acid. The liver pathological changes were observed under light microscope with HE and Masson staining. The protein expression of SIRT1and PGC-1α in the liver tissues was determined by Western blot. RESULTS: In DM group, serum FBG, TG, ALT, AST, FINS, HOMA-IR, TNF-α and IL-1 were obviously increased compared with the control group (P<0.01). The fatty changes, local necrosis, inflammation and fibrosis in the liver tissues were observed. The content of MDA in liver increased, while the activity of SOD decreased markedly. The protein expression of SIRT1 and PGC-1α was decreased (P<0.05). In TS treatment groups, all these changes in DM rats were markedly reversed by TS, and the protein expression of SIRT1 and PGC-1α in the liver tissues was markedly increased. CONCLUSION: TS may protect the rats from diabetic liver injury by increasing the expression of SIRT1 and PGC-1α, and thereby improving insulin resistance and oxidative stress.     

Effects of ERK1/2/PPARα/SCAD signal pathways on physiological cardiac hypertrophy and pathological cardiac hypertrophy

AIM：To investigate the different effects of ERK1/2/PPARα/SCAD (short-chain acyl-CoA dehydrogenase) signal pathways on the cardiac hypertrophy induced by insulin-like growth factors 1 (IGF-1) or phenylephrine (PE). METHODS：The neonatal rat cardiomyocytes induced by IGF-1 were used as the model of physiological cardiac hypertrophy, and those induced by PE were used as the model of pathological cardiac hypertrophy. The surface area of the cardiomyocytes, the expression of p-ERK1/2, PPARα and SCAD, the activity of SCAD and the content of free fatty acid in the cardiomyocytes were measured. RESULTS：Compared with the control cells, the surface area of the cardiomyocytes induced by IGF-1 and PE were both increased. Compared with the controls, the expression of SCAD and PPARα, and the activity of SCAD in the cardiomyocytes induced by IGF-1 were increased, while the expression of p-ERK1/2 was decreased. However, the cardiomyocytes treated with PE showed decreased expression of SCAD and PPARα, decreased activity of SCAD and increased expression of p-ERK1/2. Meanwhile, the decrease in free fatty acid in IGF-1-induced cardiomyocytes and the increase in PE-induced cardiomyocytes indicated that the fatty acid utilization was increased in the cardiomyocytes induced by IGF-1, but decreased in the cardiomyocytes induced by PE. CONCLUSION：The changes of p-ERK1/2, PPARα and SCAD in the cardiac hypertrophy induced by IGF-1 or PE indicate that the effects of ERK1/2/PPARα/SCAD signal pathways are different between physiological cardiac hypertrophy and pathological cardiac hypertrophy, and that SCAD may be a molecular marker of these 2 different cardiac hypertrophies and a potential therapeutic target for pathological cardiac hypertrophy.     

Effect of WT1 silencing by siRNA on expression of Wnt/β-catenin and nephrin in mouse podocytes

AIM: To study the effect of WT1 silencing by small interfering RNA (siRNA) on podocyte vitality and expression of Wnt/β-catenin and nephrin in mouse podocytes. METHODS: Conditionally immortalized mouse podocytes were cultured at 33 ℃ in RPMI-1640 medium for proliferation and induced for differentiation at 37 ℃. The podocytes were transfected with WT1 siRNA. The cell vitality was detected by MTT assay. The expression of WT1,Wnt1,β-catenin and nephrin at mRNA and protein levels was determined by real-time qRT-PCR and Western blotting. RESULTS: WT1 siRNA induced the increase in the expression of Wnt1 at mRNA and protein levels, inhibited the phosphorylation of β-catenin, and reduced the cell vitality. Meanwhile, the expression of nephrin at mRNA and protein levels was decreased. CONCLUSION: WT1 siRNA reduces the expression of nephrin in podocytes and the vitality of the cells by activating Wnt/β-catenin signaling pathway.     

Effects of G6PD silencing by siRNA on expression of HIF-1α in human colon cancer cells

AIM: To study the effects of glucose-6-phosphate dehydrogenase (G6PD) silencing by small interference RNA(siRNA) on the levels of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) and hypoxia-inducible factor 1α(HIF-1α) under hypoxia in human colon cancer cell line LoVo.METHODS: Specific siRNA expression vector targeting G6PD gene was constructed. The recombinant plasmid was identified by restriction endonuclease and DNA sequencing, and then transfected into LoVo cells. The effects of G6PD silencing were evaluated by detecting the activity and mRNA expression of G6PD. LoVo cells were cultured in vitro under hypoxic condition. NADPH levels were determined.The mRNA and protein levels of HIF-1α were analyzed by RT-PCR and Western blotting,respectively. RESULTS: The recombinant plasmid for G6PD silencing by siRNA was successfully constructed and transfected into LoVo cells. Compared with untransfected cells,the mRNA expression of G6PD in transfected cells was decreased by 43% and G6PD activity was decreased by 63.5%. Under hypoxic condition, the level of NADPH in transfected cells was significantly decreased (41% vs 100%, P<0.05).HIF-1α protein was also decreased significantly but its mRNA expression had no change as compared with the control cells. CONCLUSION: G6PD silencing by siRNA decreases NADPH level, resulting in the decline of HIF-1α stability in cancer cells under hypoxic condition. By this mechanism, G6PD silencing can influence the hypoxic responses in cancer.     

Effect of Kechuanning on airway remodeling and protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus

AIM:To investigate the effect of Kechuanning on airway remodeling and the protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus. METHODS:The asthmatic rat model induced by respiratory syncytial virus was established. The experimental rats were divided into normal group, asthma model group, low dose (0.33 mL/kg), middle dose (3.0 mL/kg) and high dose (10 mL/kg) of Kechuanning groups, and PD98059 (3 mg/kg) group. The airway responsiveness of the rats was measured by animal ventilator. The pathological changes of the lung tissues were observed by HE staining. PAS staining and Masson staining were used to observe goblet epithelial cells metaplasia and airway collagen deposition. The expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in the lung tissues of the rats was detected by immunohistochemical staining. The protein levels of ERK1/2 and p-ERK1/2 were determined by Western blot. RESULTS:Compared with model group, the airway responsiveness of the rats in middle dose and high dose of Kechuanning groups was significantly decreased (P<0.01), the injury of lung tissues was significantly decreased, the goblet epithelial cells metaplasia and airway collagen deposition were significantly reduced (P<0.01), and the expression of MMP-9 and TIMP-1 in the lung tissues was also significantly decreased (P<0.01). In addition, the protein level of p-ERK1/2 in high dose of Kechuanning group was significantly decreased compared with model group (P<0.01). CONCLUSION:Kechuanning may treat asthma by regulating the expression of p-ERK1/2 in the lung tissues and improving the airway remodeling symptoms of asthmatic rats induced by virus.     

Lentiviral vector CV072-mediated Mfn2 over-expression inhibits hepatic stellate cell activation

AIM:To construct a lentiviral vector carrying mitofusin 2 (Mfn2), and to investigate the inhibitory effect of Mfn2 on the activation of rat hepatic stellate cells and its mechanism of reducing the formation of hepatic fibrosis-related factors. METHODS:The lentiviral over-expression vector CV072-pCMV-Mfn2-EGFP containing Mfn2 was constructed and transfected into the hepatic stellate cells. The expression of green fluorescent protein was observed under fluorescence microscope, and the transfection efficiency was evaluated. The protein levels of Bax, Bcl-2, cleaved caspase-3, α-SMA, TGF-β1, Smad2 and Smad3 were detected by Western blot. The levels of type I collagen, type Ⅲ collagen and type IV collagen in the cell culture supernatants were determined by ELISA. RESULTS:Compared with control group, the apoptosis of the hepatic stellate cells transfected with lentivirus over-expression vector CV072-pCMV-Mfn2-EGFP was increased, and the protein levels of proapoptotic molecules Bax and cleaved caspase-3 were increased (P<0.01). TGF-β1/Smad pathway-related proteins TGF-β1, p-Smad2 and p-Smad3 were decreased, and the levels of fibrosis-related proteins α-SMA, type I collagen, type Ⅲ collagen and type IV collagen were decreased (P<0.01). CONCLUSION:Transfection of lentiviral over-expression vector CV072-pCMV-Mfn2-EGFP effectively inhibits hepatic stellate cell activation in vitro and may reduce the production of hepatic fibrosis-related factors by inhibiting TGF-β1/Smad pathway.     

Effect of eleutheroside B/E on proliferation and expression of PPARγ and TGF-β1 in HBZY-1 cells cultured with high glucose

AIM: To explore the effects and mechanism of eleutheroside (ETS) B or E on the proliferation of HBZY-1 cells treated with high glucose. METHODS: The HBZY-1 cells were cultured under high glucose condition. The 4th generation of HBZY-1 cells was used for determining the optimal cell density, which was consistent with the growth regulation curve of the cells. The cells were divided into 6 groups: low glucose (LG) group, high glucose (HG) group, high glucose plus ETS-B/E (low dose, medium dose and high dose) groups, and high glucose plus losartan (LTG) group. After all cells were treated with the corresponding drugs at 24 h, 48 h and 72 h, the inhibitory rate of the proliferation was measured, and the expression of TGF-β1 and PPARγ was detected by immunocytochemistry and Western blotting. RESULTS: The best cell density was 2 000 cells/well, which was complied with the basic rules of the cell growth, and high glucose significantly promoted the HBZY-1 cell proliferation. At each time point, the inhibitory effects of ETS-B/E were significantly different between HG group and LTG group on the proliferation of the HBZY-1 cells (P<0.05). The expression of TGF-β1 was significantly inhibited, and the expression of PPARγ was significantly promoted by ETS-B/E (P<0.05). ETS-E showed stronger effect than ETS-B (P<0.05) in a concentration- and time-dependent manner. CONCLUSION: ETS-B/E significantly inhibits the proliferation of HBZY-1 cells under high glucose condition by decreasing TGF-β1 expression and promoting PPARγ expression.     

Over-expression of PGC-1α reverses mitochondrial function reduction and apoptosis in OGD/R-induced neurons

AIM: To investigate the effect of over-expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) on mitochondrial morphology and cell apoptosis in the cortical neurons with oxygen glucose deprivation/reoxygenation (OGD/R). METHODS: The whole gene sequence of PGC-1α was obtained from the cerebral cortex of C57BL/6 mice by RT-PCR and cloned into the eukaryotic expression vector pEGFP-N1. The pEGFP-N1-PGC-1α was identified by PCR, and transfected into cortical neurons. The level of PGC-1α expression was identified by Western blot. The cortical neurons transfected with pEGFP-N1 and pEGFP-N1-PGC-1α vectors were treated with OGD/R. The mitochondrial mass, reactive oxygen species (ROS) and ATP production, cell apoptosis and changes of cleaved caspase-3 were detected by MitoTracker Red staining, flow cytometry, ATP metabolic assay kit and TUNEL. RESULTS: Over-expression of PGC-1α inhibited the decrease in mitochondrial biogenesis capacity and the ROS formation of OGD/R neurons (P<0.05), enhanced the ability of ATP synthesis (P<0.01), inhibited neuronal apoptosis (P<0.01) and decreased the activation of caspase-3 (P<0.01). CONCLUSION: PGC-1α over-expression inhibits neuronal apoptosis with OGD/R treatment by promoting mitochondrial biogenesis, inhibiting the production of ROS and maintaining mitochondrial function. PGC-1α may be used as a target for the development of cerebral ischemia/reperfusion injury drugs.     

Effects of JAK-STAT signaling pathway,IL-1β and IL-6 on injury of PC12 cells with X-ray irradiation

AIM: To investigate the role of JAK-STAT pathway, IL-1β and IL-6 in the PC12 cells with X-ray irradiation.METHODS: The PC12 cells were irradiated with X-ray at doses of 2, 4 and 8 Gy. After 24 h, the levels of IL-1β and IL-6 were detected by ELISA. The protein levels of p-JAK1, p-JAK2, p-STAT1, p-STAT3 and p-STAT5 were measured by Western blot.RESULTS: Compared with control group, the levels of IL-1β and IL-6 increased. The protein levels of p-JAK1, p-JAK2, p-STAT1, p-STAT3 and p-STAT5 increased with the doses of X-ray exposed.CONCLUSION: JAK-STAT signaling pathway, IL-1β and IL-6 play a role in the injury of PC12 cells with X-ray irradiation.     

Effect of pioglitazone on balance of regulatory and effector T cells of uremic apolipoprotein E knockout mice in vitro

AIM: To investigate the effects of pioglitazone on the quantity and function-related factors of regulatory and effector T cells (Treg and Teff ) of uremic apolipoprotein E knockout mice in vitro with or without the stimulation of atherosclerotic plaque-specific antigen oxidized low-density lipoprotein (oxLDL). METHODS: Uremic apolipoprotein E knockout mouse model was established by 2-step surgical procedure. After intervention with different concentrations (2 μmol/L and 20 μmol/L) of pioglitazone and PPARγ antagonist GW9662 (5 μmol/L) on splenocytes of uremic mice for 12 h in the presence or absence of oxLDL (2 mg/L), the levels of CD4⁺ CD25⁺ Foxp3⁺ Treg and IFNγ⁺ CD4⁺ Teff were determined by flow cytometry. The mRNA expressions of Foxp3 and IFNγ was detected by real-time fluorescent quantitative PCR. RESULTS: In vitro, oxLDL induced a Treg/Teff imbalance in splenocytes from the uremic mice. Pioglitazone upregulated the level of Treg and mRNA expression of Foxp3 in the presence of oxLDL, which was not antagonized by GW9662. Meanwhile, pioglitazone downregulated the level of Teff and mRNA expression of IFNγ in the presence or absence of oxLDL, which was reversed by GW9662. CONCLUSION: oxLDL induces a Treg/Teff imbalance in uremic apolipoprotein E knockout mice. Pioglitazone modulates the Treg/Teff imbalance probably through PPARγ-independent and-dependent mechanisms.     

Effects of astragaloside IV combined with ginsenoside Rg1 on autophagy and PI3K signaling pathways of PC12 cells induced by oxygen glucose deprivation/reoxygenation

ATM: To probe the effect and the mechanism of astragaloside IV and ginsenoside Rg1 on autophagy of PC12 cells induced by oxygen glucose deprivation/reoxygenation (OGD/R). METHODS: The autophagy injury model of PC12 cells induced by OGD/R was established(PC12 cells were exposed to 2 h of OGD followed by 24 h of reoxygenation). The effects of astragaloside IV combined with ginsenoside Rg1 on autophagy of PC12 cells were observed, and the mechanism was studied through PI3K Ⅰ/Akt/mTOR and PI3K Ⅲ/becline-1/Bcl-2 signaling pathways. RESULTS: After OGD/R, LC3-Ⅱ/LC3-Ⅰin PC12 cells was increased. Astragaloside IV, ginsenoside Rg1 and astragaloside IV combined with ginsenoside Rg1 restrained the increase in LC3-Ⅱ/LC3-Ⅰ, the effect of the combination was greater than using the drug alone. Ginsenoside Rg1, astragaloside IV combined with ginsenoside Rg1 up-regulated the phosphorylation level of PI3K Ⅰ, Akt and mTOR. The effects of the combination were stronger than those of using the drug alone. Astragaloside IV, astragaloside IV combined with ginsenoside Rg1 inhibited the protein expression of PI3K Ⅲ and becline-1, the effects of the combination were better than those of single astragaloside IV and single ginsenoside Rg1. Meanwhile, the combination treatment increased Bcl-2 protein expression. CONCLUSION: The autophagy of PC12 cells induced by OGD/R is inhibited by astragaloside IV and ginsenoside Rg1. Furthermore, astragaloside IV combined with ginsenoside Rg1 plays synergitic inhibition on autophagy, the mechanism may be related to PI3K Ⅰ/Akt/mTOR and PI3K Ⅲ/becline-1/Bcl-2 signaling pathways.     

PPARγ agonist inhibits high glucose-induced production of reactive oxygen species by UCP2 up-regulation

AIM: To explore the effects of PPARγ on the elevated level of reactive oxygen species (ROS) induced by high glucose and its mechanism. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured with DMEM containing high glucose (33 mmol/L D-glucose), and DMEM containing lower glucose (5.5 mmol/L D-glucose) was used as control. Superoxide anion and nitric oxide fluorescence probes were used to observe the effects of PPARγ agonist on ROS and NO productions in the HUVECs. The uncoupling protein 2 (UCP2) protein level in the HUVECs was detected by Western blotting. RESULTS: PPARγ agonist pioglitazone inhibited the ROS generation and prevented the decrease in NO level under high glucose condition, and these effects were reversed by pretreatment with PPARγ antagonist GW9662. The results of Western blotting indicated that PPARγ agonist pioglitazone up-regulated the UCP2 expression under high glucose condition, and this effect was also blocked by GW9662. Inhibition of UCP2 by genipin attenuated the effect of pioglotazone on the ROS production. CONCLUSION: Activation of PPARγ inhibits ROS generation under high glucose condition, and this effect may mediate by up-regulation of UCP2.