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| 1 | High levels of homocysteine downregulate apolipoprotein E expression via nuclear factor kappa B显示文摘AIM: To investigate the effect of high homocysteine(Hcy) levels on apolipoprotein E(apoE) expression and the signaling pathways involved in this gene regulation.METHODS: Reverse transcriptase polymerase chain reaction(RT-PCR) and Western blot were used to assess apo E expression in cells treated with various concentrations(50-500 μmol/L) of Hcy. Calcium phosphatetransient transfections were performed in HEK-293 and RAW 264.7 cells to evaluate the effect of Hcy on apoE regulatory elements [promoter and distal multienhancer 2(ME2)]. To this aim, plasmids containing the proximal apoE promoter [(-500/+73)apoE construct] alone or in the presence of ME2 [ME2/(-500/+73)apoE construct] to drive the expression of the reporter luciferase gene were used. Co-transfection experiments were carried out to investigate the downstream effectors of Hcymediated regulation of apoE promoter by using specific inhibitors or a dominant negative form of IKβ. In other co-transfections, the luciferase reporter was under the control of synthetic promoters containing multiple specific binding sites for nuclear factor kappa B(NF-κB), activator protein-1(AP-1) or nuclear factor of activated T cells(NFAT). Chromatin immunoprecipitation(ChI P)assay was accomplished to detect the binding of NF-κB p65 subunit to the apoE promoter in HEK-293 treated with 500 μmol/L Hcy. As control, cells were incubated with similar concentration of cysteine. NF-κB p65 proteins bound to DNA were immunoprecipitated with anti-p65 antibodies and DNA was identified by PCR using primers amplifying the region-100/+4 of the apoE gene. RESULTS: RT-PCR revealed that high levels of Hcy(250-750 μmol/L) induced a 2-3 fold decrease in apoE m RNA levels in HEK-293 cells, while apo E gene expression was not significantly affected by treatment with lower concentrations of Hcy(100 μmol/L). Immunoblotting data provided additional evidence for the negative role of Hcy in apoE expression. Hcy decreased apoE promoter activity, in the presence or absence of ME2, in a dose dependent manner, in both RAW 264.7 and HEK-293 cells, as revealed by transient transfection experiments. The downstream effectors of the signaling pathways of Hcy were also investigated. The inhibitory effect of Hcy on the apo E promoter activity was counteracted by MAPK/ERK kinase 1/2(MEK1/2) inhibitor U0126, suggesting that MEK1/2 is involved in the downregulation of apoE promoter activity by Hcy. Our data demonstrated that Hcy-induced inhibition of apoE took place through activation of NF-κB. Moreover, we demonstrated that Hcy activated a synthetic promoter containing three NF-κB binding sites, but did not affect promoters containing AP-1 or NFAT binding sites. ChI P experiments revealed that NF-κB p65 subunit is recruited to the apoE promoter following Hcy treatment of cells.CONCLUSION: Hcy-induced stress negatively modulates apoE expression via MEK1/2 and NF-κB activation. The decreased apo E expression in peripheral tissues may aggravate atherosclerosis, neurodegenerative diseases and renal dysfunctions. | Violeta G Trusca Adina D Mihai Elena V Fuior Ioana M Fenyo Anca V Gafencu | 2016 | World Journal of Biological Chemistry2016，7，1： | 6 |
| 2 | An approach to cleaner production:from hair burning to hair saving using alime-free unhairing system 显示文摘 | Virgilijus V Kesfuris B Violeta V | 2009 | Journal of Cleaner Production2009，17，： | 1 |
| 3 | Human health risk of dietary intake of organochlorine pesticide residues in bovine meat and tissues from Veracruz, México显示文摘 | Violeta Pardío David Martínez Argel Flores Dora Romero Víctor Suárez Karla López Roxana Uscanga | 2012 | Food Chemistry2012，，3： | 1 |
| 4 | Importance of evaluating all vascular phases on contrast-enhanced sonography in the differentiation of benign from malignant focal liver lesions 显示文摘 | Carlos N Ramon V Violeta C | 2006 | AJR2006，186，1： | 1 |
| 5 | Human health risk of dietary intake of organochlorine pesticide residues in bovine meat and tissues from Veracruz, México显示文摘 | Violeta Pardío David Martínez Argel Flores Dora Romero Víctor Suárez Karla López Roxana Uscanga | 2012 | Food Chemistry2012，，3： | 1 |
| 6 | Apoptosis and active caspase-3 expression in human Granulosa cells显示文摘 | Violeta G Katarina V Mirna S B | 2005 | Fertility and stability2005，83，2： | 1 |
| 7 | Importance of evaluating all vascular phases on contrast-enhanced sonography in the differentiation of benign from malignant focal liver lesions 显示文摘 | Carlos N Ramon V Violeta C | 2006 | AJR Am J Roentgenol2006，156，1： | 1 |
| 8 | Importance ofevaluating allvascular phases on contrast-enhanced sonography in the differentiation ofbenign from malignant focal liver lesions显示文摘 | Carlos N Ramon V Violeta C | | 0，，： | 1 |
| 9 | Importance of evaluating all vascular phases on contrast-enhanced sonography in the differentiation of benign from malignant focal liver lesions 显示文摘 | Carlos N Ramon V Violeta C | 2006 | AJR2006，186，1： | 1 |
| 10 | Apoptosis and active caspase-3 expression in human granulose cells显示文摘 | Katarina V Saraga M | 2005 | Fertility and Sterility2005，83，2： | 1 |
| 11 | Apoptosis and active caspase-3 expression in human granulosa cells显示文摘 | Violeta G Katarina V Saraga M | 2005 | Fertility and Sterility2005，83，2： | 1 |
| 12 | Importance of evaluating all vascular phases on contrast - enhanced sonography in the differentiation of benign from malignant focal liver lesions显示文摘 | Carlos N Ramon V Violeta C | 2006 | AJR2006，186，1： | 1 |
| 13 | Introduction of the QF - PCR analysis for the purposes of prenatal diagnosis in Bulgaria - estimation of applicability of 6 STR markers on chromosomes 21 and 18 显示文摘 | Silvia A Radoslava V Violeta D | 2004 | Prenat Diagn2004，24，： | 1 |
| 14 | Effect of Aronia melanocarpa Fruit Juice on the Activity of Antioxidant Enzymes in a Rat Model of Amiodarone-induced Pneumotoxicity显示文摘 | Stefka V Valcheva-Kuzmanoval Galya Ts Stavreva Violeta Y Dancheva | 2012 | J Biomed Clin Res2012，5，11： | 1 |
| 15 | Importance of evalu- ating all vascular phases on contrast - enhanced sonogra- phy in the differentiation of benign from malignant focal liver lesions显示文摘 | Carlos N Ramon V Violeta C | 2006 | AJR2006，186，1： | 1 |
| 16 | Human health risk of dietary intake of organochlorine pesticide residues in bovine meat and tissues from Veracruz, México显示文摘 | Violeta Pardío David Martínez Argel Flores Dora Romero Víctor Suárez Karla López Roxana Uscanga | 2012 | Food Chemistry2012，，3： | 1 |
| 17 | Hydrocarbon source apportionment in Mexico City using the chemical mass balance receptor model 显示文摘 | Elizabeth V Violeta M Rocio C | 2000 | Atmospheric Environment2000，34，： | 1 |
| 18 | Arsenic and chromium resistance mechanisms in the Micrococcus luteus group显示文摘High arsenic(As)and chromium(Cr)concentrations are currently receiving attention because of their negative effects on the environment and human health.Microorganisms inhabiting contaminated environments have developed resistance mechanisms against the toxicity of these pollutants.Indeed,members of the bacterial genus Micrococcus have been isolated from different toxic metal-contaminated environments;however,knowledge concerning its resistance mechanisms to As and Cr toxicity remains limited.Micrococcus luteus strains(An24,Mh,NE2TL6,and NE2TTS4)were isolated from the endosphere and soil of two heavy metal-contaminated sites in Mexico to identify differences in the resistance mechanisms by the M.luteus group.The strains were resistant to As(As^(3+)and As^(5+)),chromate,dichromate,cobalt,copper,nickel,and zinc.Genome analysis indicated that the heavy metal-resistant strains(An24,Mh,NE2TL6,and NE2TTS4)could be assigned to the M.luteus group and had more heavy metal-resistant genes(transporters,chaperones,and enzymes)compared to reference strains of the M.luteus group,M.luteus NCTC 2665^(T)and Micrococcus endophyticus JCM 16951^(T).The resistant bacteria were able to biotransform As^(3+)and As^(5+)through a carbon source-dependent mechanism.The biotransformation of As5+was potentially carried out in the cytoplasm through a thioredoxin-dependent pathway,which may be coupled with biosorption.A qualitative analysis of organic acids(OAs)identified a change in the OA profile of the metal-resistant strains that was As-or Cr-dependent.Our genomic and phenotypic findings suggest that the four M.luteus group strains evaluated in the current study have developed resistance mechanisms that may enable their survival in contaminated sites. | Ivan ARROYO-HERRERA Brenda ROMÁN-PONCE Rafael BUSTAMANTE-BRITO Joseph GUEVARA-LUNA Erika Yanet TAPIA-GARCÍA Violeta LARIOS-SERRATO Nannan ZHANG Paulina ESTRADA-DE LOS SANTOS En Tao WANG María Soledad VÁSQUEZ-MURRIETA | 2023 | Pedosphere2023，33，4： | 0 |
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