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Find video protocols related to scientific articles indexed in Pubmed.
Comparison of Magnetic Intensities for Mesenchymal Stem Cell Targeting Therapy on Ischemic Myocardial Repair: High Magnetic Intensity Improves Cell Retention but Has No Additional Functional Benefit.
Cell Transplant
PUBLISHED: 11-07-2014
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Magnetic targeting has the potential to enhance the therapeutic effects of stem cells through increasing retention of transplanted cells. To investigate the effects of magnetic targeting intensities on cell transplantation, we performed different magnetic intensities for mesenchymal stem cells (MSCs) targeting-therapy in a rat model of ischemia/reperfusion.
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Remedial Hydration Reduces the Incidence of Contrast-induced Nephropathy and Short-term Adverse Events in Patients with ST-segment Elevation Myocardial Infarction: A Single-center, Randomized Trial.
Intern. Med.
PUBLISHED: 10-15-2014
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Objective The aim of this study was to investigate whether remedial hydration (RH) reduces the incidence of contrast-induced nephropathy (CIN) and short-term adverse events in ST-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI). Methods A total of 216 consecutive STEMI patients were prospectively and randomly assigned into two groups: 108 patients in the RH group and 108 patients in the no RH (control) group. The serum creatinine (SCr) and creatinine clearance (CCr) levels were measured on admission and at 24, 48 and 72 hours after primary PCI. The rates of CIN and short-term adverse events were analyzed for each group. After surgery, the patients were categorized into four groups according to the Mehran risk score: low (?5, n =98), moderate (6-10, n=56), high (11-15, n=40) or very high (?16, n=22). Results The incidence of CIN in the RH group was lower than that observed in the control group (22/108; 20.4% vs. 38/108; 35.2%, p<0.05). The subgroup analysis showed that the rate of CIN was lower in the moderate (6/29; 20.7% vs. 13/30; 43.3%, p<0.10) and significantly lower in both the high (5/21; 23.8% vs. 10/18; 55.6%, p<0.05) and very high score groups (3/12; 25.0% vs. 8/12; 66.7%, p<0.05) among the RH patients compared to the controls. At 24, 48 and 72 hours after PCI, the patients in the RH group exhibited lower SCr levels and higher CCr levels than the patients in the control group (both p<0.05). A lower incidence of in-hospital clinical events was also observed in the RH group. Conclusion Remedial hydration decreases the occurrence of CIN and improves the short-term prognosis of STEMI patients undergoing primary PCI.
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Can we early diagnose metabolic syndrome using brachial-ankle pulse wave velocity in community population?
Chin. Med. J.
PUBLISHED: 09-06-2014
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The prevalence of metabolic syndrome (MetS) increased recently and there was still not a screening index to predict MetS. The aim of this study was to estimate whether brachial-ankle pulse wave velocity (baPWV), a novel marker for systemic arterial stiffness, could predict MetS in Chinese community population.
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Isosorbide dinitrate inhibits mechanical stress-induced cardiac hypertrophy and autophagy through downregulation of angiotensin II type 1 receptor.
J. Cardiovasc. Pharmacol.
PUBLISHED: 06-03-2014
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Mechanical stress can induce cardiac hypertrophy and autophagy. Recently, it has been reported that NO donors inhibited autophagy in human chondrocytes. Therefore, the effect of isosorbide dinitrate (ISDN) on cardiac hypertrophy and autophagy induced by mechanical stress was investigated in the present study. A 48-hour mechanical stretch and a 4-week transverse aortic constriction (TAC) were performed to induce cardiomyocyte hypertrophy in vitro and in vivo, respectively, prior to the assessment of myocardial autophagy using LC3b-II. ISDN was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Furthermore, mechanical stress was shown to upregulate angiotensin II (AngII) type1 (AT1) receptor expression in both cultured cardiomyocytes and in mouse hearts, while ISDN was demonstrated to significantly suppress the upregulation of the AT1 receptor. It was concluded that ISDN could inhibit mechanical stress-induced cardiac hypertrophy and autophagy through the downregulation of AT1 receptor expression.
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Isoorientin induces apoptosis and autophagy simultaneously by reactive oxygen species (ROS)-related p53, PI3K/Akt, JNK, and p38 signaling pathways in HepG2 cancer cells.
J. Agric. Food Chem.
PUBLISHED: 06-03-2014
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Cell death is closely related to autophagy under some circumstances; however, the effect of isoorientin (ISO) on autophagy and the interplay between apoptosis and autophagy in human hepatoblastoma cancer (HepG2) cells remains poorly understood. The present study showed that ISO induced autophagy, which was correlated with the formation of autophagic vacuoles and the overexpression of Beclin-1 and LC3-II. The autophagy inhibitor 3-methyladenine (3-MA) markedly inhibited apoptosis, and the apoptosis inhibitor ZVAD-fmk also decreased ISO-induced autophagy. In addition, the PI3K/Akt inhibitor LY294002 enhanced Beclin-1, LC3-II, and poly(ADP-ribose) polymerase (PARP) cleavage levels. Also, the reactive oxygen species (ROS) inhibitor N-acetyl-L-cysteine (NAC), the JNK inhibitor SP600125, and the p38 inhibitor SB203580 efficiently downregulated the levels of these proteins. Moreover, the p53 inhibitor pifithrin-? and the nuclear factor (NF)-?B inhibitor pyrrolidinedithiocarbamic acid (PDTC) clearly suppressed Beclin-1 and LC3-II and increased cytochrome c release, caspase-3 activation, and PARP cleavage. These results demonstrated for the first time that ISO simultaneously induced apoptosis and autophagy by ROS-related p53, PI3K/Akt, JNK, and p38 signaling pathways. Furthermore, ISO-induced apoptosis by activating the Fas receptor-mediated apoptotic pathway and suppressing the p53 and PI3K/Akt-dependent NF-?B signaling pathway, with the subsequent increase in the release of cytochrome c, caspase-3 activation, and PARP cleavage.
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Simultaneous determination of 15 phenolic constituents of Chinese black rice wine by HPLC-MS/MS with SPE.
J. Food Sci.
PUBLISHED: 04-07-2014
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This study established a new method for quantitative and qualitative determination of certain components in black rice wine, a traditional Chinese brewed wine. Specifically, we combined solid-phase extraction and high-performance liquid chromatography (HPLC) with triple quadrupole mass spectrometry (MS/MS) to determine 8 phenolic acids, 3 flavonols, and 4 anthocyanins in black rice wine. First, we clean samples with OASIS HLB cartridges and optimized extraction parameters. Next, we performed separation on a SHIM-PACK XR-ODS column (I.D. 3.0 mm × 75 mm, 2.2 ?m particle size) with a gradient elution of 50% aqueous acetonitrile (V/V) and water, both containing 0.2% formic acid. We used multiple-reaction monitoring scanning for quantification, with switching electrospray ion source polarity between positive and negative modes in a single chromatographic run. We detected 15 phenolic compounds properly within 38 min under optimized conditions. Limits of detection ranged from 0.008 to 0.030 mg/L, and average recoveries ranged from 60.8 to 103.1% with relative standard deviation ?8.6%. We validated the method and found it to be sensitive and reliable for quantifying phenolic compounds in rice wine matrices.
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A novel mechanism for momordin Ic-induced HepG2 apoptosis: involvement of PI3K- and MAPK-dependent PPAR? activation.
Food Funct
PUBLISHED: 03-04-2014
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Momordin Ic is a natural triterpenoid saponin found in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. Momordin Ic has been previously demonstrated to induce HepG2 cell apoptosis in a ROS-mediated PI3K and MAPK pathway-dependent manner. In the present study, the underlying mechanisms of PI3K and MAPK pathway-mediated PPAR?, and PGC-1? co-regulator activation, as well as the effects of downstream proteins, COX-2 and FoxO4, on cell apoptosis were investigated. The results demonstrated that momordin Ic activated PPAR? and inhibited COX-2. PGC-1? and FoxO4 expressions were increased by the PI3K or MAPK pathways. Furthermore, PPAR? inhibition decreased p-p38 and FoxO4 expression, and restored COX-2 expression. ROS inhibition exerted little effect on PPAR?, COX-2 and FoxO4 expression but affected PGC-1? expression. These results revealed the involvement of PI3K and MAPK-dependent PPAR? activation in momordin Ic-induced apoptosis, providing more detailed information underlying the pro-apoptotic mechanism of momordin Ic in HepG2 cell apoptosis.
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Mechanical stress triggers cardiomyocyte autophagy through angiotensin II type 1 receptor-mediated p38MAP kinase independently of angiotensin II.
PLoS ONE
PUBLISHED: 01-01-2014
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Angiotensin II (Ang II) type 1 (AT1) receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC) were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.
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Amide-type adduct of dopamine - plausible cause of Parkinson diseases.
Subcell. Biochem.
PUBLISHED: 01-01-2014
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Dopamine is the endogenous neurotransmitter produced by nigral neurons. Dopamine loss can trigger not only prominent secondary morphological changes, but also changes in the density and sensitivity of dopamine receptors; therefore, it is a sign of PD development. The reasons for dopamine loss are attributed to dopamine's molecular instability due to it is a member of catecholamine family, whose catechol structure contributes to high oxidative stress through enzymatic and non-enzymatic oxidation. Oxidative stress in the brain easily leads to the lipid peroxidation reaction due to a high concentration of polyunsaturated fatty acids (PUFA), such as docosahexaenoic acid (DHA, C22:6/?-3) and arachidonic acid (AA, C18:4/?-6). Recent studies have shown that lipid hydroperoxides, the primary peroxidative products, could non-specifically react with primary amino groups to form N-acyl-type (amide-linkage) adducts. Therefore, based on the NH2-teminals in dopamine's structure, the aims of this chapter are to describes the possibility that reactive LOOH species derived from DHA/AA lipid peroxidation may modify dopamine to form amide-linkage dopamine adducts, which might be related to etiology of Parkinson's diseases.
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Additive effect of zinc oxide nanoparticles and isoorientin on apoptosis in human hepatoma cell line.
Toxicol. Lett.
PUBLISHED: 09-08-2013
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Metal nanomaterial could effectively decrease tumor resistance to anti-cancer drugs. In this paper, we have explored the synergistic effect and mechanisms of zinc oxide nanoparticles (ZnO Nps) and isoorientin (ISO) on cytotoxicity in human hepatoma (HepG2) cells. The results showed that ZnO Nps could exert dose- and time-dependent cytotoxicity in HepG2 cells, and the combining treatment resulted in a greater cytotoxicity than single treatment. ZnO Nps could synergistically potentiate ISO to induce apoptosis through resulting in mitochondrial dysfunction, inhibiting the phosphorylation of Akt and ERK1/2, and enhancing the phosphorylation of JNK and P38. Additionally, ZnO Nps were uptaked by cells through endocytic pathway and it enhanced the cellular uptake of ISO, while no significant injury was found in normal liver cells after the combined treatment. These results suggest that the combination of metal nanoparticle with anti-cancer drugs may provide a promising alternative for novel cancer treatments.
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Isoorientin attenuates lipopolysaccharide-induced pro-inflammatory responses through down-regulation of ROS-related MAPK/NF-?B signaling pathway in BV-2 microglia.
Mol. Cell. Biochem.
PUBLISHED: 06-27-2013
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Isoorientin (ISO) is a flavonoid compound in the human diet, and has been known to possess various bioactivities. However, the effects of ISO on microglia inflammation have not been investigated. The current study investigates the neuroprotective effect of ISO in LPS-activated mouse microglial (BV-2) cells. ISO significantly increased the BV-2 cells viability, blocked the protein expression of inducible nitric oxide synthase and cyclooxygenase-2, and decreased the production of nitric oxide, pro-inflammatory cytokines including tumor necrosis factor-? and interleukin-1?. The activation of mitogen-activated protein kinases (MAPKs) was blocked by ISO, and NF-?B nuclear translocation was decreased by ISO both alone and together with NF-?B inhibitor (PDTC) and MAPKs inhibitors (U0126, SP 600125, and SB 203580). Furthermore, ISO strongly quenched intracellular reactive oxygen species (ROS) generation. ROS inhibitor (N-acetyl cysteine, NAC) significantly inhibited pro-inflammatory cytokines release and NF-?B and MAPKs activation, indicating that ISO attenuated neuroinflammation by inhibiting the ROS-related MAPK/NF-?B signaling pathway.
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Allele-specific expression of angiotensinogen in human subcutaneous adipose tissue.
Hypertension
PUBLISHED: 05-06-2013
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The angiotensinogen gene is genetically linked with hypertension, but the mechanistic basis for association of sequence variants in the promoter and coding region of the gene remains unclear. An E-box at position -20 has been hypothesized to control the level of angiotensinogen expression, but its mechanistic importance for angiotensinogen expression in human tissues is uncertain. We developed an allele-specific polymerase chain reaction-based assay to distinguish between angiotensinogen mRNA derived from variants at the -20 position (rs5050) in the angiotensinogen promoter in adipose tissues obtained during surgery. The assay takes advantage of linkage disequilibrium between the rs5050 (located in the promoter) and rs4762 (located in the coding region) single nucleotide polymorphisms. This strategy allowed us to assess the level of allele-specific expression in A-20C heterozygous subjects comparing the relative proportion of each allele with the total, thus eliminating the problem of variability in the level of total angiotensinogen mRNA among subjects. We show that angiotensinogen mRNA derived from the -20C allele is expressed significantly higher than that derived from the -20A allele in subcutaneous adipose tissue, and increased expression correlates with enriched chromatin binding of upstream stimulatory factor-2 to the -20C E-box compared with -20A. This may be depot selective because we were unable to detect these differences in omental adipose. This provides the first data directly comparing expression of angiotensinogen mRNA and differential transcription factor binding derived from 2 variant alleles in human tissue where the ratio of expression of one allele to another can be accurately determined.
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Hypertension in mice with transgenic activation of the brain renin-angiotensin system is vasopressin dependent.
Am. J. Physiol. Regul. Integr. Comp. Physiol.
PUBLISHED: 03-27-2013
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An indispensable role for the brain renin-angiotensin system (RAS) has been documented in most experimental animal models of hypertension. To identify the specific efferent pathway activated by the brain RAS that mediates hypertension, we examined the hypothesis that elevated arginine vasopressin (AVP) release is necessary for hypertension in a double-transgenic model of brain-specific RAS hyperactivity (the "sRA" mouse model). sRA mice experience elevated brain RAS activity due to human angiotensinogen expression plus neuron-specific human renin expression. Total daily loss of the 4-kDa AVP prosegment (copeptin) into urine was grossly elevated (?8-fold). Immunohistochemical staining for AVP was increased in the supraoptic nucleus of sRA mice (~2-fold), but no quantitative difference in the paraventricular nucleus was observed. Chronic subcutaneous infusion of a nonselective AVP receptor antagonist conivaptan (YM-087, Vaprisol, 22 ng/h) or the V(2)-selective antagonist tolvaptan (OPC-41061, 22 ng/h) resulted in normalization of the baseline (~15 mmHg) hypertension in sRA mice. Abdominal aortas and second-order mesenteric arteries displayed AVP-specific desensitization, with minor or no changes in responses to phenylephrine and endothelin-1. Mesenteric arteries exhibited substantial reductions in V(1A) receptor mRNA, but no significant changes in V(2) receptor expression in kidney were observed. Chronic tolvaptan infusion also normalized the (5 mmol/l) hyponatremia of sRA mice. Together, these data support a major role for vasopressin in the hypertension of mice with brain-specific hyperactivity of the RAS and suggest a primary role of V(2) receptors.
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Momordin Ic induces HepG2 cell apoptosis through MAPK and PI3K/Akt-mediated mitochondrial pathways.
Apoptosis
PUBLISHED: 02-19-2013
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Momordin Ic is a natural triterpenoid saponin enriched in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. So far, there is little scientific evidence for momordin Ic with regard to the anti-tumor activities. The aim of this work was to elucidate the anti-tumor effect of momordin Ic and the signal transduction pathways involved. We found that momordin Ic induced apoptosis in human hepatocellular carcinoma HepG2 cells, which were supported by DNA fragmentation, caspase-3 activation and PARP cleavage. Meanwhile, momordin Ic triggered reactive oxygen species (ROS) production together with collapse of mitochondrial membrane potential, cytochrome c release, down-regulation of Bcl-2 and up-regulation of Bax expression. The activation of p38 and JNK, inactivation of Erk1/2 and Akt were also demonstrated. Although ROS production rather than NO was stimulated, the expression of iNOS and HO-1 were altered after momordin Ic treatment for 4 h. Furthermore, the cytochrome c release, caspase-3 activation, Bax/Bcl-2 expression and PARP cleavage were promoted with LY294002 and U0126 intervention but were blocked by SB203580, SP600125, PI3K activator, NAC and 1,400 W pretreatment, demonstrating the mitochondrial disruption. Furthermore, momordin Ic combination with NAC influenced MAPK, PI3K/Akt and HO-1, iNOS pathways, MAPK and PI3K/Akt pathways also regulated the expression of HO-1 and iNOS. These results indicated that momordin Ic induced apoptosis through oxidative stress-regulated mitochondrial dysfunction involving the MAPK and PI3K-mediated iNOS and HO-1 pathways. Thus, momordin Ic might represent a potential source of anticancer candidate.
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Chicoric acid induces apoptosis in 3T3-L1 preadipocytes through ROS-mediated PI3K/Akt and MAPK signaling pathways.
J. Agric. Food Chem.
PUBLISHED: 02-11-2013
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Chicoric acid has been reported to possess various bioactivities. However, the antiobesity effects of chicoric acid remain poorly understood. In this study, we investigated the effects of chicoric acid on 3T3-L1 preadipocytes and its molecular mechanisms of apoptosis. Chicoric acid inhibited cell viability and induced apoptosis in 3T3-L1 preadipocytes which was characterized by chromatin condensation and poly ADP-ribose-polymerase (PARP) cleavage. Mitochondrial membrane potential (MMP) loss, Bax/Bcl-2 dysregulation, cytochrome c release, and caspase-3 activation were observed, indicating mitochondria-dependent apoptosis induced by chicoric acid. Furthermore, PI3K/Akt and MAPK (p38 MAPK, JNK, and ERK1/2) signaling pathways were involved in chicoric acid-induced apoptosis. The employment of protein kinase inhibitors LY294002, SB203580, SP600125, and U0126 revealed that PI3K/Akt signaling pathway interplayed with MAPK signaling pathways. Moreover, chicoric acid induced reactive oxygen species (ROS) generation. Pretreatment with the antioxidant N-acetylcysteine (NAC) significantly blocked cell death and changes of Akt and MAPK signalings induced by chicoric acid. In addition, chicoric acid down regulated HO-1 and COX-2 via the PI3K/Akt pathway.
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Mechanical stretch changes coronary artery fibroblasts function by upregulating HSF1 protein expression.
Int. J. Biol. Macromol.
PUBLISHED: 02-05-2013
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The study is designed to investigate effect of mechanical stretch on the function of fibroblast cells. Human coronary artery fibroblasts were cultured. They were divided into two groups: stretch group (stretch for 24h) and no-stretch group (did not stretch). ELISA analysis was used for detection of collagen secretion. CCK-8 method was used for detection of cells proliferation. RT-PCR method was used for detection of MMP, TIMP, IL-6, alpha-SMA, HSF1 and HSP70 mRNA expression. Western-blotting method was used for detection of HSF1 protein expression. Results showed that cells proliferation in stretch group was stronger than that in no-stretch group. Hydroxyproline secretion in stretch group was more than that in no-stretch group. MMP-9/TIMP, alpha-SMA, IL-6, HSF1 and HSP70 in stretch group was higher than those in no-stretch group. Western-blotting analysis showed that HSF1 protein expression was upregulated in stretch group. It can be concluded that mechanical stretch changed human coronary artery fibroblasts cells proliferation, collagen formation, the secretion of inflammatory factor possibly by upregulating HSF1 protein expression.
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Inhibitory effect of atorvastatin on AGE-induced HCAEC apoptosis by upregulating HSF-1 protein.
Int. J. Biol. Macromol.
PUBLISHED: 01-25-2013
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This study evaluates effect and mechanism of atorvastatin on human coronary artery endothelial cells (HCAEC) apoptosis. Results have shown that HCAEC apoptosis had increased with increasing concentration of AGEs. Atorvastatin may decrease HCAEC apoptosis, but the effect can be attenuated by PI3K inhibitor. Secretion of PI3K and P-Akt in HCAEC increased with increasing concentration of AGEs. Secretion of PI3K in HCAEC may be decreased by atorvastatin. The effect may be attenuated by PI3K inhibitor. HSF-1, HSP-70 mRNA expression level decreased with increasing concentration of AGEs. Atorvastatin may attenuate AGEs-induced HSF-1, HSP-70 mRNA expression in HCAEC, but the effect can be attenuated by PI3K inhibitor. It can be concluded that AGE can dose-dependently promote HCAEC apoptosis by the PI3K/AKT pathway. Atorvastatin may attenuate the effect possibly by upregulating HSF-1.
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The interaction of sesamol with DNA and cytotoxicity, apoptosis, and localization in HepG2 cells.
Food Chem
PUBLISHED: 01-10-2013
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Sesamol, a nutritional antioxidant phenolic compound present in sesame seed, has a potential therapeutic molecule effect against cancers. In this study, the interaction between sesamol and DNA was investigated by employing ultraviolet/visible (UV/Vis), fluorescence, circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR), and molecular modeling. The fluorescence analysis indicated that the fluorescence quenching mechanism of sesamol by calf thymus DNA (ctDNA) occurred through static quenching. The UV/Vis, CD, FT-IR spectra and molecular docking results implied that the primary binding mode was minor groove binding. Furthermore, the intracellular interaction of sesamol with DNA and its bioactivity effect were explored. The cell activity results demonstrated that sesamol induced hepatic cell line (HepG2) death. The acridine orange (AO)/ethidium bromide (EB) staining assay and DNA fragmentation confirmed that sesamol could efficiently induce the apoptosis of HepG2 cells. Moreover, addition of sesamol to HepG2 cells resulted in nuclear localization, as visualized by confocal microscopy.
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Maternal docosahexaenoic acid feeding protects against impairment of learning and memory and oxidative stress in prenatally stressed rats: possible role of neuronal mitochondria metabolism.
Antioxid. Redox Signal.
PUBLISHED: 12-01-2011
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Docosahexaenoic acid (22:6n-3; DHA) is known to play a critical role in postnatal brain development. However, no study has been performed to investigate its preventive effect on prenatal stress-induced behavioral and molecular alterations in offspring. In the present study, rats were exposed to restraint stress on days 14-20 of pregnancy, three times a day, 2 hours each time; DHA was given at the doses of 100 and 300?mg/kg/day for two weeks.
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Neuronal receptor activity-modifying protein 1 promotes energy expenditure in mice.
Diabetes
PUBLISHED: 02-25-2011
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Receptor activity-modifying proteins (RAMPs) 1, 2, and 3 are unusual accessory proteins that dictate the binding specificity of two G protein-coupled receptors involved in energy homeostasis: calcitonin gene-related peptide (CGRP) and amylin receptors. These proteins are expressed throughout the central nervous system (CNS), including in the brain regions involved in the regulation of energy homeostasis, but the significance of CNS RAMPs in the control of energy balance remains unknown.
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Angiotensinergic signaling in the brain mediates metabolic effects of deoxycorticosterone (DOCA)-salt in C57 mice.
Hypertension
PUBLISHED: 01-24-2011
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Low-renin hypertension accounts for ? 25% of essential hypertensive patients. It is modeled in animals by chronic delivery of deoxycorticosterone acetate and excess dietary sodium (the DOCA-salt model). Previous studies have demonstrated that DOCA-salt hypertension is mediated through activation of the brain renin-angiotensin system. Here, we demonstrate robust metabolic phenotypes of DOCA-salt treatment. Male C57BL/6J mice (6 to 8 weeks old) received a subcutaneous pellet of DOCA (50 mg for 21 days) and were offered a 0.15 mol/L NaCl drink solution in addition to regular chow and tap water. Treatment resulted in mild hypertension, a blunting of weight gain, gross polydipsia, polyuria, and sodium intake, alterations in urinary sodium and potassium turnover, and serum sodium retention. Most strikingly, DOCA-salt mice exhibited no difference in food intake but did exhibited a large elevation in basal metabolic rate. Normalization of blood pressure by hydralazine (500 mg/L in drink solutions) attenuated the hydromineral phenotypes and renal renin suppression effects of DOCA-salt but had no effect on the elevated metabolic rate. In contrast, intracerebroventricular infusion of the angiotensin II type 1 receptor antagonist losartan (5 ?g/h) attenuated the elevation in metabolic rate with DOCA-salt treatment. Together, these data illustrate the necessity of angiotensinergic signaling within the brain, independent of blood pressure alterations, in the metabolic consequences of DOCA-salt treatment.
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Relationship between aortic valve calcification and the severity of coronary atherosclerotic disease.
J. Heart Valve Dis.
PUBLISHED: 09-18-2010
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Aortic valve calcification (AVC), which has been confirmed to be associated with various risk factors of cardiac disease, is common in the elderly and associated with increased cardiovascular mortality. It has been hypothesized that AVC is associated with coronary atherosclerotic disease, and its severity.
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Assessing the neuroprotective effect of antioxidant food factors by application of lipid-derived dopamine modification adducts.
Methods Mol. Biol.
PUBLISHED: 01-15-2010
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Advances in understanding the neurodegenerative pathologies are creating new opportunities for the development of neuroprotective therapies, such as antioxidant food factors, lifestyle modification and drugs. However, the biomarker by which the effect of the agent on neurodegeneration is determined is limited. We here address hexanoyl dopamine (HED), one of novel dopamine adducts derived from brain polyunsaturated acid, referring to its in vitro formation, potent toxicity to SH-SY5Y cells, and application to assess the neuroprotective effect of antioxidative food factors. Dopamine is a neurotransmitter, and its deficiency is a characterized feature in Parkinsons disease (PD); thus, HED provides a new insight into the understanding of dopamine biology and pathophysiology of PD and a novel biomarker for the assessment of neuroprotective therapies. We have established an analytical system for the detection of HED and its toxicity to the neuroblstoma cell line, SH-SY5Y cells. Here, we discuss the characteristics of the system and its applications to investigate the neuroprotective effect of several antioxidants that originate from food.
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Bioinformatic analysis of gene sets regulated by ligand-activated and dominant-negative peroxisome proliferator-activated receptor gamma in mouse aorta.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 12-17-2009
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Drugs that activate peroxisome proliferator-activated receptor (PPAR) gamma improve glucose sensitivity and lower blood pressure, whereas dominant-negative mutations in PPARgamma cause severe insulin resistance and hypertension. We hypothesize that these PPARgamma mutants regulate target genes opposite to those of ligand-mediated activation, and we tested this hypothesis on a genomewide scale.
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Deep magnetic capture of magnetically loaded cells for spatially targeted therapeutics.
Biomaterials
PUBLISHED: 10-15-2009
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Magnetic targeting has recently demonstrated potential in promoting magnetically loaded cell delivery to target lesion, but its application is limited by magnetic attenuation. For deep magnetic capture of cells for spatial targeting therapeutics, we designed a magnetic pole, in which the magnetic field density can be focused at a distance from the pole. As flowing through a tube served as a model of blood vessels, the magnetically loaded mesenchymal stem cells (MagMSCs) were highly enriched at the site distance from the magnetic pole. The cell capture efficiency was positively influenced by the magnetic flux density, and inversely influenced by the flow velocity, and well-fitted with the deductive value by theoretical considerations. It appeared to us that the spatially-focused property of the magnetic apparatus promises a new deep targeting strategy to promote homing and engraftment for cellular therapy.
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Assessing the neuroprotective effect of antioxidative food factors by application of lipid-derived dopamine modification adducts.
Methods Mol. Biol.
PUBLISHED: 09-29-2009
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Advances in understanding the neurodegenerative pathologies are creating new opportunities for the development of neuroprotective therapies, such as antioxidant food factors, lifestyle modification, and drugs. However, the biomarker by which to determine the effect of the agent on neurodegeneration is limited. We here address hexanoyl dopamine (HED), one of novel dopamine adducts derived from brain polyunsaturated acid, referring to its in vitro formation, potent toxicity to SH-SY5Y cells, and application to assess the neuroprotective effect of antioxidative food factors. Dopamine is a neurotransmitter and its deficiency is a characterized feature in Parkinsons disease (PD), thereby HED represents a new addition to understanding of dopamine biology and pathophysiology of PD and a novel biomarker for the assessment of neuroprotective therapies. We have established an analytical system using for the detection of HED and its toxicity to the neuroblstoma cell line, SH-SY5Y cells. Here, we discuss the characteristics of the system and its applications to investigate the neuroprotective effect of several antioxidants that originate from food.
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Regulation of renin gene expression by oxidative stress.
Hypertension
PUBLISHED: 05-11-2009
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Increased arterial pressure, angiotensin II, and cytokines each result in feedback inhibition of renin gene expression. Because angiotensin II and cytokines can stimulate reactive oxygen species production, we tested the hypothesis that oxidative stress may be a mediator of this inhibition. Treatment of renin-expressing As4.1 cells with the potent cytokine tumor necrosis factor-alpha caused an increase in the steady-state levels of cellular reactive oxygen species, which was reversed by the antioxidant N-acetylcysteine. Exogenous H(2)O(2) caused a dose- and time-dependent decrease in the level of endogenous renin mRNA and decreased the transcriptional activity of a 4.1-kb renin promoter fused to luciferase, which was maximal when the renin enhancer was present. The effect of H(2)O(2) appeared to be specific to renin, because there was no change in the expression of beta-actin or cyclophilin mRNA or transcriptional activity of the SV40 promoter. The tumor necrosis factor-alpha-induced decrease in renin mRNA was partially reversed by either N-acetylcysteine or panepoxydone, a nuclear factor kappaB (NFkappaB) inhibitor. Interestingly, H(2)O(2) did not induce NFkappaB in As4.1 cells, and panepoxydone had no effect on the downregulation of renin mRNA by H(2)O(2). The transcriptional activity of a cAMP response element-luciferase construct was decreased by both tumor necrosis factor-alpha and H(2)O(2). These data suggest that cellular reactive oxygen species can negatively regulate renin gene expression via an NFkappaB-independent mechanism involving the renin enhancer and inhibiting cAMP response element-mediated transcription. Our data further suggest that tumor necrosis factor-alpha decreases renin expression through both NFkappaB-dependent and NFkappaB-independent mechanisms, the latter involving the production of reactive oxygen species.
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Repeated autologous bone marrow mononuclear cell therapy in patients with large myocardial infarction.
Eur. J. Heart Fail.
PUBLISHED: 05-06-2009
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We sought to determine whether repeat administration of bone marrow mononuclear cells (BMC) can improve left ventricular function compared with a single infusion in patients with large acute myocardial infarction (AMI).
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Astaxanthin protects neuronal cells against oxidative damage and is a potent candidate for brain food.
Forum Nutr
PUBLISHED: 04-07-2009
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Astaxanthin (AST) is a powerful antioxidant that occurs naturally in a wide variety of living organisms. Based on the report claiming that AST could cross the brain-blood barrier, the aim of this study was to investigate the neuroprotective effect of AST by using an oxidative stress-induced neuronal cell damage system. The treatment with DHA hydroperoxide (DHA-OOH) or 6-hydroxydopamine (6-OHDA), either of which is a reactive oxygen species (ROS)-inducing neurotoxin, led to a significant decrease in viable dopaminergic SH-SY5Y cells by the MTT assay, whereas a significant protection was shown when the cells were pretreated with AST. Moreover, 100 nM AST pretreatment significantly inhibited intracellular ROS generation that occurred in either DHA-OOH- or 6-OHDA-treated cells. The neuroprotective effect of AST is suggested to be dependent upon its antioxidant potential and mitochondria protection; therefore, it is strongly suggested that treatment with AST may be effective for oxidative stress-associated neurodegeneration and a potential candidate for natural brain food.
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Astaxanthin inhibits reactive oxygen species-mediated cellular toxicity in dopaminergic SH-SY5Y cells via mitochondria-targeted protective mechanism.
Brain Res.
PUBLISHED: 03-14-2009
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Astaxanthin is a powerful antioxidant that occurs naturally in a wide variety of living organisms. The aim of this study is to investigate the effect and the mechanism of astaxanthin on reactive oxygen species (ROS)-mediated apoptosis in dopaminergic SH-SY5Y cells. The treatment with DHA hydroperoxide (DHA-OOH) or 6-hydroxydopamine (6-OHDA), either of which is ROS-inducing neurotoxin, led to a significant decrease in viable dopaminergic SH-SY5Y cells by MTT assay, whereas a significant protection was shown while the cells were pretreated with astaxanthin. Moreover, 100 nM astaxanthin pretreatment significantly inhibited apoptosis, mitochondrial abnormalities and intracellular ROS generation occurred in either DHA-OOH- or 6-OHDA-treated cells. The neuroprotective effect of astaxanthin is suggested to be dependent upon its antioxidant potential and mitochondria protection; therefore, it is suggested that astaxanthin may be an effective treatment for oxidative stress-associated neurodegeneration.
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Intravascular ultrasound assessment of the incidence and predictors of edge dissections after drug-eluting stent implantation.
JACC Cardiovasc Interv
PUBLISHED: 02-14-2009
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We used intravascular ultrasound (IVUS) to assess incidence, predictors, morphology, and angiographic findings of edge dissections after drug-eluting stent (DES) implantation.
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Leptin signaling in the nucleus tractus solitarii increases sympathetic nerve activity to the kidney.
Hypertension
PUBLISHED: 02-14-2009
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The hypothalamic arcuate nucleus was initially regarded as the principal site of leptin action, but there is increasing evidence for functional leptin receptors in extrahypothalamic sites, including the nucleus tractus solitarii (NTS). We demonstrated previously that arcuate injection of leptin increases sympathetic nerve activity (SNA) to brown adipose tissue and kidney. In this study, we tested the hypothesis that leptin signaling in the NTS affects sympathetic neural outflow. Using a stereotaxic device in anesthetized rats, we microinjected leptin (0.25 to 1.00 microg) or saline into the NTS while recording SNA to kidney and brown adipose tissue. Microinjection of leptin into the commissural and medial subnuclei of the caudal NTS at the level of the area postrema in Sprague-Dawley rats produced a dose-related increase in renal SNA (+112+/-15% with leptin 1 microg; n=7; P<0.001) but did not increase SNA to brown adipose tissue (-15+/-12%; P value not significant). This effect depended on intact functional leptin receptors, because it was not observed in Zucker obese rats that have a missense mutation in the leptin receptor. Rostral NTS injection of leptin failed to increase SNA, indicating that leptin signaling in the NTS is probably confined to the caudal NTS at the level of the area postrema. In summary, this study demonstrates that leptin signaling in the caudal NTS increases SNA to the kidney but not to the brown adipose tissue. The study strengthens the concept of a distributed brain network of leptin action and demonstrates that these distributed brain sites can mediate contrasting sympathetic responses to leptin.
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A volumetric intravascular ultrasound comparison of early drug-eluting stent thrombosis versus restenosis.
JACC Cardiovasc Interv
PUBLISHED: 01-23-2009
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We compared intravascular ultrasound findings of drug-eluting stent (DES)-treated lesions that developed thrombosis versus in-stent restenosis (ISR).
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MAPK signaling pathways regulate mitochondrial-mediated apoptosis induced by isoorientin in human hepatoblastoma cancer cells.
Food Chem. Toxicol.
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Isoorientin (ISO) (CAS RN: 4261-42-1) is a flavonoid compound that can be extracted from several plant species, such as Phyllostachys pubescens, Patrinia, and Drosophyllum lusitanicum. ISO is able to induce apoptosis through mitochondrial dysfunction and inhibition of PI3K/Akt signaling pathway in HepG2 cells, however, the effects of ISO on MAPK signaling pathways remain unknown. The present study investigated the effects of ISO on this pathway, and the roles of MAPK kinases on mitochondrial-mediated apoptosis in HepG2 cells. The results showed that ISO induced cell death in a dose- and time-dependent manner, and induction apoptosis is main cause for ISO-induced cytotoxicity in HepG2 cells. ISO significantly inhibited the levels of ERK1/2 kinase and increased the expression of JNK and p38 kinases. Furthermore, U0126 (an ERK1/2 inhibitor) significantly enhanced the ISO-induced the Bax/Bcl-2 ratio, the release of cytochrome c to the cytosol fraction, and the levels of cleaved caspase-3. While SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor) markedly prevented the expression of these proteins induced by ISO. Furthermore, the ROS inhibitor (NAC) notably promoted the inhibited effect of ISO on the ERK1/2 kinase. NAC also suppressed the p-JNK and p-p38, but failed to reverse the effects of ISO. These results demonstrated for the first time that ISO induces apoptosis in HepG2 cells through inactivating ERK1/2 kinase and activating JNK and p38 kinases, and ROS stimulated by ISO is able to activate the MAPK singaling pathway as the upstream signaling molecules. Initiating event of the mitochondrial-mediated apoptosis induced by ISO is MAPK signals.
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Carnosic acid attenuates lipopolysaccharide-induced liver injury in rats via fortifying cellular antioxidant defense system.
Food Chem. Toxicol.
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The study investigated the protective effects of carnosic acid (CA), the principal constituent of rosemary, on lipopolysaccharide (LPS)-induced oxidative/nitrosative stress and hepatotoxicity in rats. CA was administered orally to rats at doses of 15, 30 and 60 mg/kg body weight before LPS challenge (single intraperitoneal injection, 1 mg/kg body weight). The results revealed that CA inhibited LPS-induced liver damage and disorder of lipid metabolism, which were mainly evidenced by decreased serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. CA also inhibited LPS-induced oxidative/nitrosative stress by decreasing lipid peroxidation, protein carbonylation, and serum levels of nitric oxide. Histopathological examination demonstrated that CA could improve pathological abnormalities and reduce the immigration of inflammatory cells in liver tissues with LPS challenge. Concurrently, CA potently inhibited the LPS-induced rise in serum levels of the pro-inflammatory cytokines tumor necrosis factor-? and interleukin-6. CA supplementation markedly enhanced the bodys cellular antioxidant defense system by restoring the levels of superoxide dismutase, glutathione peroxidase, and glutathione in serum and liver after the LPS challenge. In conclusion, the present study suggests that CA successfully and dose dependently attenuates LPS-induced hepatotoxicity possibly by preventing cytotoxic effects of oxygen free radicals, NO and cytokines.
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Herbacetin induces apoptosis in HepG2 cells: Involvements of ROS and PI3K/Akt pathway.
Food Chem. Toxicol.
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Herbacetin (HER) is a natural flavonoid compound that can be extracted from Ramose Scouring Rush Herb, and its biological and pharmacological activities lack of corresponding attention. In this study, the apoptotic effect of HER against the human hepatoma cell line (HepG2) was investigated. The results showed that HepG2 cells apoptosis occurred in a dose-dependent manner within 48h incubated with HER, which was confirmed by DNA fragmentation, nuclear shrinkage, and poly (ADP-ribose) polymerase (PARP) cleavage. HER at 25-100?M induced a mitochondria-dependent apoptotic pathway associated with Bcl-2/Bax ratio decrease, mitochondrial membrane potential (??) collapse, cytochrome c release, and caspase-3 activation. Increasing expression of peroxisome proliferator-activated receptor-? coactivator 1? (PGC-1?) was also observed in HER-treated cells. Furthermore, the addition of a ROS inhibitor (N-Acetyl-l-cysteine, NAC) significantly attenuated the apoptosis induced by HER and also blocked the expression of PGC-1? protein. Additionally, HER effectively inhibited the phosphorylation of Akt and the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 increased the inhibition effect of HER on Akt phosphorylation. These findings provide evidences that HER induces HepG2 apoptosis in a ROS-mediated mitochondria-dependent manner that correlate with the inactivation of the PI3K/Akt pathway.
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Free radical scavenging and immunomodulatory activities of Ganoderma lucidum polysaccharides derivatives.
Carbohydr Polym
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Polysaccharides extracted from the fruit body of Ganoderma lucidum were sulfated and carboxymethylated as reported. Free radical scavenging and immunomodulatory effects of sulfated and carboxymethylated polysaccharides were studied. Generally, sulfated polysaccharides showed better bioactivities than that of carboxymethylated polysaccharides. The two derivatives were injected intraperitoneally with or without 5-fluorouracil over a period of 7 days in BALB/c female mice. The polysaccharide derivatives increased mouse thymus and spleen index, an indication of improved immunity in mice. At the same time, they improved superoxide dismutase and glutathione peroxidase contents in the mice body.
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Isoorientin induces apoptosis through mitochondrial dysfunction and inhibition of PI3K/Akt signaling pathway in HepG2 cancer cells.
Toxicol. Appl. Pharmacol.
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Isoorientin (ISO) is a flavonoid compound that can be extracted from several plant species, such as Phyllostachys pubescens, Patrinia, and Drosophyllum lusitanicum; however, its biological activity remains poorly understood. The present study investigated the effects and putative mechanism of apoptosis induced by ISO in human hepatoblastoma cancer (HepG2) cells. The results showed that ISO induced cell death in a dose-dependent manner in HepG2 cells, but no toxicity in human liver cells (HL-7702) and buffalo rat liver cells (BRL-3A) treated with ISO at the indicated concentrations. ISO-induced cell death included apoptosis which characterized by the appearance of nuclear shrinkage, the cleavage of poly (ADP-ribose) polymerase (PARP) and DNA fragmentation. ISO significantly (p<0.01) increased the Bax/Bcl-2 ratio, disrupted the mitochondrial membrane potential (MMP), increased the release of cytochrome c, activated caspase-3, and enhanced intracellular levels of reactive oxygen species (ROS) and nitric oxide (NO). In addition, ISO effectively inhibited the phosphorylation of Akt and increased FoxO4 expression. The PI3K/Akt inhibitor LY294002 enhanced the apoptosis-inducing effect of ISO. However, LY294002 markedly quenched ROS and NO generation and diminished the protein expression of heme peroxidase enzyme (HO-1) and inducible nitric oxide synthase (iNOS). Furthermore, the addition of a ROS inhibitor (N-acetyl cysteine, NAC) or iNOS inhibitor (N-[3-(aminomethyl) benzyl] acetamidine, dihydrochloride, 1400W) significantly diminished the apoptosis induced by ISO and also blocked the phosphorylation of Akt. These results demonstrated for the first time that ISO induces apoptosis in HepG2 cells and indicate that this apoptosis might be mediated through mitochondrial dysfunction and PI3K/Akt signaling pathway, and has no toxicity in normal liver cells, suggesting that ISO may have good potential as a therapeutic and chemopreventive agent for liver cancer.
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PPAR? regulates resistance vessel tone through a mechanism involving RGS5-mediated control of protein kinase C and BKCa channel activity.
Circ. Res.
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Activation of peroxisome proliferator-activated receptor-? (PPAR?) by thiazolidinediones lowers blood pressure, whereas PPAR? mutations cause hypertension. Previous studies suggest these effects may be mediated through the vasculature, but the underlying mechanisms remain unclear.
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Novel physiological properties of ethanol extracts from Eremurus chinensis Fedtsch. roots: in vitro antioxidant and anticancer activities.
Food Funct
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Eremurus chinensis Fedtch. (ECF) with nutritious roots, belonging to the genus of Eremurus, is a special species grown in China. However, the functional properties of ECF roots have not been intensely investigated. The antioxidant and anticancer effects of ethanol extracts from E. chinensis Fedtch. roots (ECFE) were evaluated in the present study. ECFE exhibited high radical-scavenging activities on DPPH and ABTS radicals, strong reducing power and Fe(2+)-chelating activity. ECFE also effectively protected biological macromolecules including proteins, lipids and DNA against oxidative damage induced by Cu(2+)/H(2)O(2) and AAPH systems. Moreover, the MTT assay revealed that ECFE inhibited proliferation of HepG2 cells in a dose- and time-dependent manner. Western blot analysis demonstrated that treatment with ECFE led to cell apoptosis hallmarked by PARP cleavage. Additionally, caspase-3 activation, cytochrome C (Cyt-C) release and increase of Bax/Bcl-2 ratio suggested that mitochondria-mediated signaling pathway might be involved in ECFE-induced apoptosis in HepG2 cells. These results demonstrate the remarkable potentiality of ECFE as a valuable source of antioxidants which possess original anticancer abilities.
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A brain leptin-renin angiotensin system interaction in the regulation of sympathetic nerve activity.
Am. J. Physiol. Heart Circ. Physiol.
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The sympathetic nervous system, leptin, and renin-angiotensin system (RAS) have been implicated in obesity-associated hypertension. There is increasing evidence for the presence of both leptin and angiotensin II receptors in several key brain cardiovascular and metabolic control regions. We tested the hypothesis that the brain RAS plays a facilitatory role in the sympathetic nerve responses to leptin. In rats, intracerebroventricular (ICV) administration of losartan (5 ?g) selectively inhibited increases in renal and brown adipose tissue (BAT) sympathetic nerve activity (SNA) produced by leptin (10 ?g ICV) but did not reduce the SNA responses to corticotrophin-releasing factor (CRF) or the melanocortin receptor agonist MTII. In mice with deletion of angiotensin II type-1a receptors (AT(1a)R(-/-)), increases in renal and BAT SNA induced by leptin (2 ?g ICV) were impaired whereas SNA responses to MTII were preserved. Decreases in food intake and body weight with ICV leptin did not differ in AT(1a)R(-/-) vs. AT(1a)R(+/+) mice. ICV leptin in rats increased AT(1a)R and angiotensin-converting enzyme (ACE) mRNA in the subfornical organ and AT(1a)R mRNA in the arcuate nucleus, suggesting leptin-induced upregulation of the brain RAS in specific brain regions. To evaluate the role of de novo production of brain angiotensin II in SNA responses to leptin, we treated rats with captopril (12.5 ?g ICV). Captopril attenuated leptin effects on renal and BAT SNA. In conclusion, these studies provide evidence that the brain RAS selectively facilitates renal and BAT sympathetic nerve responses to leptin while sparing effects on food intake.
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Gene trapping uncovers sex-specific mechanisms for upstream stimulatory factors 1 and 2 in angiotensinogen expression.
Hypertension
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A single-nucleotide polymorphism (C/A) located within an E-box at the -20 position of the human angiotensinogen (AGT) promoter may regulate transcriptional activation through differential recruitment of the transcription factors upstream stimulatory factor (USF) 1 and 2. To study the contribution of USF1 on AGT gene expression, mice carrying a (-20C) human AGT (hAGT) transgene were bred with mice harboring a USF1 gene trap allele designed to knock down USF1 expression. USF1 mRNA was reduced relative to controls in liver (9 ± 1%), perigenital adipose (16 ± 3%), kidney (17 ± 1%), and brain (34 ± 2%) in double-transgenic mice. This decrease was confirmed by electrophoretic mobility shift assay. Chromatin immunoprecipitation analyses revealed a decrease in USF1, with retention of USF2 binding at the hAGT promoter in the liver of male mice. hAGT expression was reduced in the liver and other tissues of female but not male mice. The decrease in endogenous AGT expression was insufficient to alter systolic blood pressure at baseline but caused reduced systolic blood pressure in female USF1 gene trap mice fed a high-fat diet. Treatment of USF1 knockdown males with intravenous adenoviral short hairpin RNA targeting USF2 resulted in reduced expression of USF1, USF2, and hAGT protein. Our data from chromatin immunoprecipitation assays suggests that this decrease in hAGT is attributed to decreased USF2 binding to the hAGT promoter. In conclusion, both USF1 and USF2 are essential for AGT transcriptional regulation, and distinct sex-specific and tissue-specific mechanisms are involved in the activities of these transcription factors in vivo.
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Metabolic rate regulation by the renin-angiotensin system: brain vs. body.
Pflugers Arch.
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Substantial evidence supports a role for the renin-angiotensin system (RAS) in the regulation of metabolic function, but an apparent paradox exists where genetic or pharmacological inhibition of the RAS occasionally has similar physiological effects as chronic angiotensin infusion. Similarly, while RAS targeting in animal models has robust metabolic consequences, effects in humans are more subtle. Here, we review the data supporting a role for the RAS in metabolic rate regulation and propose a model where the local brain RAS works in opposition to the peripheral RAS, thus helping to explain the paradoxically similar effects of RAS supplementation and inhibition. Selectively modulating the peripheral RAS or brain RAS may thus provide a more effective treatment paradigm for obesity and obesity-related disorders.
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Fibroblast growth factor receptor 4 polymorphisms and susceptibility to coronary artery disease.
DNA Cell Biol.
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Fibroblast growth factors (FGFs) and their receptors (FGFRs) play crucial roles in vascular smooth muscle cell proliferation and atherosclerosis and, therefore, may potentially affect the development of coronary artery disease (CAD). FGFR4 rs351855 (Gly388Arg) polymorphism has shown to be a risk factor for many diseases. The aim of this study was to investigate the association between FGFR4 polymorphisms and the susceptibility to CAD in the Chinese population. Two polymorphisms, rs351855 (Gly388Arg) and rs641101, were detected by polymerase chain reaction-restriction fragment length polymorphism and direct sequencing in 687 CAD cases and 732 age-matched controls. Data were analyzed using the chi-square test. Results showed that frequencies of GA genotype, AA genotype, and A allele in rs351855 (Gly388Arg) polymorphism were significantly lower in CAD patients than in controls (odds ratio (OR)=0.78, 95% confidence intervals (CIs): 0.62-0.98, p=0.034; OR=0.58, 95% CI: 0.42-0.80, p=0.001; and OR=0.77, 95% CI: 0.66-0.90, p=0.001, respectively). The rs641101 polymorphism did not show any correlation with CAD. Haplotype analysis revealed that rs351855 and rs641101 AG haplotype also had lower frequency in CAD patients (OR=0.79, 95% CI: 0.67-0.92, p=0.002). Our data suggested that the FGFR4 rs351855 (Gly388Arg) polymorphism and AG haplotype (rs351855 and rs641101) could act as protective factors against CAD in the Chinese population and indicated that a single gene polymorphism could have diverse functions in different diseases.
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Regulation of renin expression by the orphan nuclear receptors Nr2f2 and Nr2f6.
Am. J. Physiol. Renal Physiol.
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Understanding the transcriptional mechanisms of renin expression is key to understanding the regulation of the renin-angiotensin system. We previously identified the nuclear receptors RAR/RXR and Nr2f6 (EAR2) as positive and negative transcriptional regulators of renin expression, respectively (Liu X, Huang X, Sigmund CD. Circ Res 92: 1033-1040, 2003). Both mediate their effects through a hormone response element (HRE) within the renin enhancer. Here, we determined whether another nuclear receptor, Nr2f2 (Coup-TFII, Arp-1), identified in a screen of proteins that bind the HRE, also regulates renin expression. Luciferase assays indicate that Nr2f2 negatively regulates the renin promoter more potently than Nr2f6. Gel-shift and chromatin immunoprecipitation (ChIP) indicate that Nr2f2 and Nr2f6 can bind directly to the renin enhancer through the HRE. Surprisingly, baseline expression of endogenous renin was not effected when Nr2f2 was knocked down in As4.1 cells, whereas knockdown of Nr2f6 increased renin expression twofold. Interestingly, however, knockdown of Nr2f2 augmented the induction of renin expression caused by retinoic acid. These data indicate that both Nr2f6 and Nr2f2 can negatively regulate the renin promoter, under baseline conditions and in response to physiological queues, respectively. Therefore, Nr2f2 may require an initiating signal that results in a change at the chromatin level or activation of another transcription factor to exert its effects. We conclude that both Nr2f2 and Nr2f6 negatively regulate renin promoter activity, but may do so by divergent mechanisms.
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Astaxanthin alleviates brain aging in rats by attenuating oxidative stress and increasing BDNF levels.
Food Funct
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Astaxanthin (AST) is a carotenoid pigment which possesses potent antioxidative, anti-inflammatory, and neuroprotective properties. The aim of this study was to investigate whether administration of AST had protective effects on d-galactose-induced brain aging in rats, and further examined its protective mechanisms. The results showed that AST treatment significantly restored the activities of glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD), and increased glutathione (GSH) contents and total antioxidant capacity (T-AOC), but decreased malondialdehyde (MDA), protein carbonylation and 8-hydroxy-2- deoxyguanosine (8-OHdG) levels in the brains of aging rats. Furthermore, AST increased the ratio of Bcl-2/Bax, but decreased the expression of Cyclooxygenase-2 (COX-2) in the brains of aging rats. Additionally, AST ameliorated histopathological changes in the hippocampus and restored brain derived neurotrophic factor (BDNF) levels in both the brains and hippocampus of aging rats. These results suggested that AST could alleviate brain aging, which may be due to attenuating oxidative stress, ameliorating hippocampus damage, and upregulating BDNF expression.
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