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1.
Medicine (Baltimore) ; 99(20): e20326, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32443384

RESUMO

The hypomethylation of the Cyclin D1 (CCND1) promoter induced by excess oxidative stress likely promotes the development of hepatitis B virus-associated hepatocellular carcinoma (HBV-HCC). We aimed to evaluate methylation status of the CCND1 promoter as a new plasma marker for the detection of HBV-HCC.We consecutively recruited 191 participants, including 105 patients with HBV-HCC, 54 patients with chronic hepatitis B (CHB), and 32 healthy controls (HCs). Using methylation-specific polymerase chain reaction, we identified the methylation status of the CCND1 promoter in plasma samples. We analyzed the expression levels of the CCND1 mRNA in peripheral blood mononuclear cells by using quantitative real-time PCR. We assessed the plasma levels of superoxide dismutase, 8-hydroxydeoxyguanosine and malondialdehyde by using enzyme-linked immunosorbent assays.Patients with HBV-HCC (23.81%) presented a reduced methylation frequency compared with patients with CHB (64.81%) or HCs (78.13%) (P < .001). When receiver operating characteristic curves were plotted for patients with HBV-HCC versus CHB, the methylation status of the CCND1 promoter yielded diagnostic parameter values for the area under the curve of 0.705, sensitivity of 76.19%, and specificity of 64.81%, thus outperforming serum alpha-fetoprotein (AFP), which had an area under the curve of 0.531, sensitivity of 36.19%, and specificity of 90.74%. Methylation of the CCND1 promoter represents a prospective diagnostic marker for patients with AFP-negative HBV-HCC and AFP-positive CHB. The expression levels of CCND1 mRNA was increased in patients with HBV-HCC compared with patients with CHB (Z = -4.946, P < .001) and HCs (Z = -6.819, P < .001). Both the extent of oxidative injury and antioxidant capacity indicated by the superoxide dismutase, 8-hydroxydeoxyguanosine and malondialdehyde levels were increased in patients with HBV-HCC. Clinical follow up of patients with HBV-HCC revealed a worse overall survival (P = .012, log-rank test) and a decreased progression-free survival (HR = 0.109, 95%CI: 0.031-0.384) for the unmethylated CCND1 group than methylated CCND1 group.Our study confirms that oxidative stress appears to correlate with plasma levels of CCND1 promoter methylation, and the methylation status of the CCND1 promoter represents a prospective biomarker with better diagnostic performance than serum AFP levels.


Assuntos
Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/fisiopatologia , Ciclina D1/metabolismo , Hepatite B Crônica/complicações , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/fisiopatologia , 8-Hidroxi-2'-Desoxiguanosina/metabolismo , Idoso , Biomarcadores Tumorais , Carcinoma Hepatocelular/diagnóstico , Metilação de DNA/fisiologia , Detecção Precoce de Câncer , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Neoplasias Hepáticas/diagnóstico , Masculino , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Estresse Oxidativo/fisiologia , Regiões Promotoras Genéticas/fisiologia , Estudos Prospectivos , Curva ROC , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade , Superóxido Dismutase/metabolismo , alfa-Fetoproteínas/análise
2.
Arterioscler Thromb Vasc Biol ; 40(6): 1464-1478, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32268789

RESUMO

OBJECTIVE: Despite the current antiatherosclerotic and antithrombotic therapies, the incidence of advanced atherosclerosis-associated clinical events remains high. Whether long noncoding RNAs (lncRNAs) affect the progression of atherosclerosis and whether they are potential targets for the treatment of advanced atherosclerosis are poorly understood. Approach and Results: The progression of atherosclerotic lesions was accompanied by dynamic alterations in lncRNA expression, as revealed by RNA sequencing and quantitative polymerase chain reaction. Among the dynamically changing lncRNAs, we identified a novel lncRNA, lncRNA Associated with the Progression and Intervention of Atherosclerosis (RAPIA), that was highly expressed in advanced atherosclerotic lesions and in macrophages. Inhibition of RAPIA in vivo not only repressed the progression of atherosclerosis but also exerted atheroprotective effects similar to those of atorvastatin on advanced atherosclerotic plaques that had already formed. In vitro assays demonstrated that RAPIA promoted proliferation and reduced apoptosis of macrophages. A molecular sponge interaction between RAPIA and microRNA-183-5p was demonstrated by dual-luciferase reporter and RNA immunoprecipitation assays. Rescue assays indicated that RAPIA functioned at least in part by targeting the microRNA-183-5p/ITGB1 (integrin ß1) pathway in macrophages. In addition, the transcription factor FoxO1 (forkhead box O1) could bind to the RAPIA promoter region and facilitate the expression of RAPIA. CONCLUSIONS: The progression of atherosclerotic lesions was accompanied by dynamic changes in the expression of lncRNAs. Inhibition of the pivotal lncRNA RAPIA may be a novel preventive and therapeutic strategy for advanced atherosclerosis, especially in patients resistant or intolerant to statins.


Assuntos
Aterosclerose/terapia , Expressão Gênica , Macrófagos/metabolismo , RNA Longo não Codificante/antagonistas & inibidores , RNA Longo não Codificante/genética , Animais , Apoptose/efeitos dos fármacos , Aterosclerose/genética , Aterosclerose/prevenção & controle , Atorvastatina/farmacologia , Proliferação de Células/efeitos dos fármacos , Progressão da Doença , Proteína Forkhead Box O1/metabolismo , Humanos , Integrina beta1/metabolismo , Macrófagos/química , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , MicroRNAs/metabolismo , MicroRNAs/farmacologia , Regiões Promotoras Genéticas/fisiologia , Células RAW 264.7 , RNA Longo não Codificante/fisiologia
3.
J Mol Biol ; 432(4): 815-827, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-31962123

RESUMO

Optogenetic activation of receptors has advantages compared with chemical or ligand treatment because of its high spatial and temporal precision. Especially in the brain, the use of a genetically encoded light-tunable receptor is superior to direct infusion or systemic drug treatment. We applied light-activatable TrkB receptors in the mouse brain with reduced basal activity by incorporating Cry2PHR mutant, Opto-cytTrkB(E281A). Upon AAV mediated gene delivery, this form was expressed at sufficient levels in the mouse hippocampus (HPC) and medial entorhinal cortex (MEC) retaining normal canonical signal transduction by the blue light stimulus, even by delivery of noninvasive LED light on the mouse head. Within target cells, where its expression was driven by a cell type-specific promoter, Opto-cytTrkB(E281A)-mediated TrkB signaling could be controlled by adjusting light-stimulating conditions. We further demonstrated that Opto-cytTrkB(E281A) could locally induce TrkB signaling in axon terminals in the MEC-HPC. In summary, Opto-cytTrkB(E281A) will be useful for elucidating time- and region-specific roles of TrkB signaling ranging from cellular function to neural circuit mechanisms.


Assuntos
Hipocampo/metabolismo , Receptor trkB/metabolismo , Animais , Axônios/metabolismo , Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Córtex Entorrinal/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Optogenética , Regiões Promotoras Genéticas/genética , Regiões Promotoras Genéticas/fisiologia , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Receptor trkB/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
4.
Int J Mol Sci ; 20(18)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505838

RESUMO

WAX INDUCER1/SHINE1 (WIN1) belongs to the AP2/EREBP transcription factor family and plays an important role in wax and cutin accumulation in plants. Here we show that BnWIN1 from Brassica napus (Bn) has dual functions in wax accumulation and oil synthesis. Overexpression (OE) of BnWIN1 led to enhanced wax accumulation and promoted growth without adverse effects on oil synthesis under salt stress conditions. Lipid profiling revealed that BnWIN1-OE plants accumulated more waxes with elevated C29-alkanes, C31-alkanes, C28-alcohol, and C29-alcohol relative to wild type (WT) under salt stress. Moreover, overexpression of BnWIN1 also increased seed oil content under normal growth conditions. BnWIN1 directly bound to the promoter region of genes encoding biotin carboxyl carrier protein 1 (BCCP1), glycerol-3-phosphate acyltransferase 9 (GPAT9), lysophosphatidic acid acyltransferase 5 (LPAT5), and diacylglycerol acyltransferase 2 (DGAT2) involved in the lipid anabolic process. Overexpression of BnWIN1 resulted in upregulated expression of numerous genes involved in de novo fatty acid synthesis, wax accumulation, and oil production. The results suggest that BnWIN1 is a transcriptional activator to regulate the biosynthesis of both extracellular and intracellular lipids.


Assuntos
Brassica napus/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Lipídeos/biossíntese , Pressão Osmótica , Óleos Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Brassica napus/genética , Lipídeos/genética , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/fisiologia , Fatores de Transcrição/genética
5.
mBio ; 10(5)2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31551335

RESUMO

A major challenge in finding a cure for HIV-1/AIDS is the difficulty in identifying and eradicating persistent reservoirs of replication-competent provirus. Long noncoding RNAs (lncRNAs, >200 nucleotides) are increasingly recognized to play important roles in pathophysiology. Here, we report the first genome-wide expression analysis of lncRNAs in HIV-1-infected primary monocyte-derived macrophages (MDMs). We identified an lncRNA, which we named HIV-1-enhanced lncRNA (HEAL), that is upregulated by HIV-1 infection of MDMs, microglia, and T lymphocytes. Peripheral blood mononuclear cells of HIV-1-infected individuals show elevated levels of HEAL Importantly, HEAL is a broad enhancer of multiple HIV-1 strains because depletion of HEAL inhibited X4, R5, and dual-tropic HIV replications and the inhibition was rescued by HEAL overexpression. HEAL forms a complex with the RNA-binding protein FUS, which facilitates HIV replication through at least two mechanisms: (i) HEAL-FUS complex binds the HIV promoter and enhances recruitment of the histone acetyltransferase p300, which positively regulates HIV transcription by increasing histone H3K27 acetylation and P-TEFb enrichment on the HIV promoter, and (ii) HEAL-FUS complex is enriched at the promoter of the cyclin-dependent kinase 2 gene, CDK2, to enhance CDK2 expression. Notably, HEAL knockdown and knockout mediated by RNA interference (RNAi) and CRISPR-Cas9, respectively, prevent HIV-1 recrudescence in T cells and microglia upon cessation of azidothymidine treatment in vitro Our results suggest that silencing of HEAL or perturbation of the HEAL-FUS ribonucleoprotein complex could provide a new epigenetic silencing strategy to eradicate viral reservoirs and effect a cure for HIV-1/AIDS.IMPORTANCE Despite our increased understanding of the functions of lncRNAs, their potential to develop HIV/AIDS cure strategies remains unexplored. A genome-wide analysis of lncRNAs in HIV-1-infected primary monocyte-derived macrophages (MDMs) was performed, and 1,145 differentially expressed lncRNAs were identified. An lncRNA named HIV-1-enhanced lncRNA (HEAL) is upregulated by HIV-1 infection and promotes HIV replication in T cells and macrophages. HEAL forms a complex with the RNA-binding protein FUS to enhance transcriptional coactivator p300 recruitment to the HIV promoter. Furthermore, HEAL knockdown and knockout prevent HIV-1 recrudescence in T cells and microglia upon cessation of azidothymidine treatment, suggesting HEAL as a potential therapeutic target to cure HIV-1/AIDS.


Assuntos
Epigênese Genética , Regulação Viral da Expressão Gênica/fisiologia , Infecções por HIV/fisiopatologia , HIV-1/fisiologia , Regiões Promotoras Genéticas/fisiologia , RNA Longo não Codificante/fisiologia , Replicação Viral/fisiologia , Humanos
6.
Mol Immunol ; 114: 179-188, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31376731

RESUMO

The production of inflammatory cytokines is closely related to pathogen-associated molecular pattern (PAMP)-triggered activation of the Toll-like receptor (TLR), intracellular signal transduction pathways such as MAPK and NF-κB, and histone modifications. Histone methylation, a type of histone modifications, is mainly accomplished by a class of SET family proteins containing highly conserved SET domains. In the present study, we found that SET domain-containing protein 4 (SETD4) regulated inflammatory cytokines in response to TLR agonists. LPS stimulation led to the enhanced SETD4 expression, while the increased IL-6 and TNF-α release from LPS-stimulated RAW264.7 cells was attenuated by depletion of SETD4 using RNA interference. The results were further confirmed in BMDMs and pMφ isolated from SETD4-deficient mice where SETD4-/- macrophages treated with LPS, BLP or Poly(I:C) showed down-regulated IL-6 and TNF-α mRNA and protein levels when compared with SETD4+/+ macrophages. Moreover, the mRNA levels of all NF-κB-dependent genes including IL-1ß, IL-10, NFKBA, DUSP1, CCL2, CCL5, and CXCL10 in SETD4-/- macrophages were substantially reduced. To further clarify the regulatory mechanism(s) by which SETD4 modulates inflammatory cytokines, we examined the effect of SETD4 on the activation of MAPK and NF-κB signalling pathways, and found that knockout of SETD4 had no effect on phosphorylation of p38, ERK, JNK, p65, and IκBα. Notably, SETD4 translocated quickly from the cytosol to the nucleus upon LPS stimulation, suggesting that SETD4 may exert its regulatory function downstream of the MAPK and NF-κB pathways. To characterize this, we performed an in vitro HMTase assay to measure histone methyltransferase (HMTase) activity of SETD4. H3K4me1 and H3K4me2 levels were enhanced dramatically with the supplementation of SETD4, whereas both H3K4me1 and H3K4me2 were strongly attenuated in SETD4-/- BMDMs. Moreover, the LPS-stimulated recruitment of H3K4me1 and H3K4me2 at both TNF-α and IL-6 promoters was severely impaired in SETD4-/- BMDMs. Collectively, these results demonstrate that SETD4 positively regulates IL-6 and TNF-α expression in TLR agonist-stimulated macrophages by directly activating H3K4 methylation.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Citocinas/metabolismo , Lisina/metabolismo , Macrófagos/metabolismo , Metiltransferases/metabolismo , Receptores Toll-Like/metabolismo , Animais , Linhagem Celular , Histonas/metabolismo , Inflamação/metabolismo , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/metabolismo , Fosforilação/fisiologia , Regiões Promotoras Genéticas/fisiologia , Células RAW 264.7 , Transdução de Sinais/fisiologia
7.
Nutrients ; 11(8)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31370166

RESUMO

Iron is an essential nutrient needed for physiological functions, particularly during the developmental period of the early childhood of at-risk populations. The purpose of this study was to investigate, in an experimental colitis, the consequences of daily oral iron ingestion in the early period on the inflammatory response, the spleen T helper (Th) profiles and the associated molecular mechanisms. Juvenile mice orally received microencapsulated ferric iron or water for 6 weeks. On adult mice, we induced a sham or experimental trinitrobenzene sulfonic acid (TNBS) moderate colitis during the last week of the experiment before sacrificing the animals 7 days later. The severity of the gut inflammation was assessed by macroscopic damage scores (MDS) and the myeloperoxidase activity (MPO). Th profiles were evaluated by the examination of the splenic gene expression of key transcription factors of the Th differentiation (Tbet, Gata3, Foxp3 and RORγ) and the methylation of their respective promoter. While TNBS-induced colitis was associated with a change of the Th profile (notably an increase in the Tbet/Gata3 ratio in the spleen), the colitis-inhibition induced by ferric iron was associated with a limitation of the splenic Th profiles perturbation. The inhibition of the splenic Tbet gene overexpression was associated with an inhibition of promoter hypomethylation. In summary, mice treated by long-term oral ferric iron in the early period of life exhibited an inhibition of colitis associated with the inhibition of the splenic Tbet promoter hypomethylation and gene overexpression.


Assuntos
Colite/prevenção & controle , Compostos Férricos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regiões Promotoras Genéticas/fisiologia , Fatores de Transcrição/metabolismo , Administração Oral , Adulto , Envelhecimento , Animais , Ilhas de CpG , Composição de Medicamentos , Compostos Férricos/administração & dosagem , Humanos , Masculino , Metilação , Camundongos , Camundongos Endogâmicos BALB C , Fatores de Transcrição/genética
8.
Genes (Basel) ; 10(7)2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-31252700

RESUMO

The anaerobic degradation of benzoate in bacteria involves the benzoyl-CoA central pathway. Azoarcus/Aromatoleum strains are a major group of anaerobic benzoate degraders, and the transcriptional regulation of the bzd genes was extensively studied in Azoarcus sp. CIB. In this work, we show that the bzdR regulatory gene and the PN promoter can also be identified upstream of the catabolic bzd operon in all benzoate-degrader Azoarcus/Aromatoleum strains whose genome sequences are currently available. All the PN promoters from Azoarcus/Aromatoleum strains described here show a conserved architecture including three operator regions (ORs), i.e., OR1 to OR3, for binding to the BzdR transcriptional repressor. Here, we demonstrate that, whereas OR1 is sufficient for the BzdR-mediated repression of the PN promoter, the presence of OR2 and OR3 is required for de-repression promoted by the benzoyl-CoA inducer molecule. Our results reveal that BzdR binds to the PN promoter in the form of four dimers, two of them binding to OR1. The BzdR/PN complex formed induces a DNA loop that wraps around the BzdR dimers and generates a superstructure that was observed by atomic force microscopy. This work provides further insights into the existence of a conserved BzdR-dependent mechanism to control the expression of the bzd genes in Azoarcus strains.


Assuntos
Acil Coenzima A/genética , Azoarcus/genética , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Anaerobiose , Proteínas de Bactérias/química , Benzoatos/química , Genes Reguladores , Microscopia de Força Atômica , Regiões Operadoras Genéticas/genética , Óperon/genética , Óperon/fisiologia , Regiões Promotoras Genéticas/fisiologia , Conformação Proteica , Fatores de Transcrição/genética , Transcrição Genética
9.
Biomed Pharmacother ; 117: 109092, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31203134

RESUMO

BACKGROUND: 17ß-Estradiol (E2) is a critical regulator of trophoblast function during pregnancy. Serum- and glucocorticoid-inducible kinase (SGK1) has been shown to regulate specific cellular targets downstream of E2. However, whether and how SGK1 directly mediates the regulatory effects of E2 on trophoblasts functions remain unknown. METHODS: SGK1 expression in human villous samples and serum E2 levels were measured in women with early pregnancy loss (EPL) and healthy pregnant women. The effect of E2 on SGK1 regulation was assessed using luciferase reporter gene assay and Chromatin Immunoprecipitation assay. The mediation of regulatory effects of E2 by SGK1 on trophoblast functions including cell viability, invasion and related signaling molecules such as B cell leukemia/lymphoma 6, E-cadherin, matrix metalloproteinase 2, α-ENaC, vascular endothelial growth factor, and the phosphorylation status of FOXO1 and AKT were evaluated in HTR8/SVneo cells transfected with SGK1 knockdown plasmid with/without E2 treatment. RESULTS: SGK1 protein levels in human villous samples and serum E2 levels were decreased in patients with EPL compared to controls. E2 (10 nM) increased SGK1 promoter activity directly through estrogen receptor. E2-activated SGK1 enhanced cell viability, invasion and downstream targets in trophoblast cells. SGK1 knockdown abrogated the above responses to E2 treatment. CONCLUSIONS: SGK1 mediates the effects of E2 on trophoblast viability and invasion, suggesting that SGK1 acts as a key node in regulating the cross-talk at the feto-maternal interface during the development of placenta and might be a potential therapeutic target for EPL.


Assuntos
Sobrevivência Celular/fisiologia , Estradiol/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Trofoblastos/metabolismo , Caderinas/metabolismo , Linhagem Celular , Movimento Celular/fisiologia , Feminino , Células Endoteliais da Veia Umbilical Humana , Humanos , Metaloproteinase 2 da Matriz/metabolismo , Placenta/metabolismo , Gravidez , Regiões Promotoras Genéticas/fisiologia , Receptores Estrogênicos/metabolismo
10.
Plant Sci ; 283: 247-255, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128695

RESUMO

Chrysanthemums require continuous short-days (SD) for anthesis. FTL3 (FLOWERING LOCUS T-like 3), a floral promoter expressed in chrysanthemum leaf, forms a complex with its interacting partner FDL1 to induce floral meristem identity gene AFL1. We explored the FTL3 induction mechanism during SD repeats in Chrysanthemum seticuspe. CsFTL3 expression was not immediately induced by a shift from long-day (LD) to SD, but gradually increased until the capitulum development stage under repeated SDs. Overexpression of CsFTL3 transgene increased endogenous leaf CsFTL3 induction under SD but not LD. Overexpression of CsFDL1 promoted anthesis and increased CsAFL1 and CsFTL3 expression under SD. Loss-of-function of CsFDL1 by RNAi resulted in delayed anthesis and downregulation of leaf CsAFL1 and CsFTL3, indicating the necessity of CsFDL1 for CsFTL3 induction. Overexpression of an antagonistic protein of CsFTL3 or CsFDL1 inhibited leaf CsFTL3 induction. CsFTL3 expression was positively regulated during SDs by a feedback mechanism involving the CsFTL3-CsFDL1 complex. Furthermore, flowering was accomplished by feedback with high levels of CsFTL3 induction under repeated SDs.


Assuntos
Chrysanthemum/crescimento & desenvolvimento , Flores/crescimento & desenvolvimento , Proteínas de Plantas/fisiologia , Chrysanthemum/metabolismo , Chrysanthemum/fisiologia , Retroalimentação Fisiológica , Flores/metabolismo , Flores/fisiologia , Técnicas de Silenciamento de Genes , Fotoperíodo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Regiões Promotoras Genéticas/fisiologia , Transcriptoma
11.
Proc Natl Acad Sci U S A ; 116(24): 11776-11785, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31123148

RESUMO

The cytoplasmic coat protein complex-II (COPII) is evolutionarily conserved machinery that is essential for efficient trafficking of protein and lipid cargos. How the COPII machinery is regulated to meet the metabolic demand in response to alterations of the nutritional state remains largely unexplored, however. Here, we show that dynamic changes of COPII vesicle trafficking parallel the activation of transcription factor X-box binding protein 1 (XBP1s), a critical transcription factor in handling cellular endoplasmic reticulum (ER) stress in both live cells and mouse livers upon physiological fluctuations of nutrient availability. Using live-cell imaging approaches, we demonstrate that XBP1s is sufficient to promote COPII-dependent trafficking, mediating the nutrient stimulatory effects. Chromatin immunoprecipitation (ChIP) coupled with high-throughput DNA sequencing (ChIP-seq) and RNA-sequencing analyses reveal that nutritional signals induce dynamic XBP1s occupancy of promoters of COPII traffic-related genes, thereby driving the COPII-mediated trafficking process. Liver-specific disruption of the inositol-requiring enzyme 1α (IRE1α)-XBP1s signaling branch results in diminished COPII vesicle trafficking. Reactivation of XBP1s in mice lacking hepatic IRE1α restores COPII-mediated lipoprotein secretion and reverses the fatty liver and hypolipidemia phenotypes. Thus, our results demonstrate a previously unappreciated mechanism in the metabolic control of liver protein and lipid trafficking: The IRE1α-XBP1s axis functions as a nutrient-sensing regulatory nexus that integrates nutritional states and the COPII vesicle trafficking.


Assuntos
Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Endorribonucleases/metabolismo , Nutrientes/metabolismo , Transporte Proteico/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/fisiologia , Proteína 1 de Ligação a X-Box/metabolismo , Animais , Movimento Celular/fisiologia , Imunoprecipitação da Cromatina/métodos , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/fisiologia , Lipídeos/fisiologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Regiões Promotoras Genéticas/fisiologia
12.
Chem Res Toxicol ; 32(5): 899-909, 2019 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-30821442

RESUMO

One response to oxidation of guanine (G) to 8-oxo-7,8-dihydroguanine (OG) in a gene promoter is regulation of mRNA expression suggesting an epigenetic-like role for OG. A proposed mechanism involves G oxidation within a potential G-quadruplex-forming sequence (PQS) in the promoter, enabling a structural shift from B-DNA to a G-quadruplex fold (G4). When OG was located in the coding vs template strand, base excision repair led to an on/off transcriptional switch. Herein, a G-rich, potential Z-DNA-forming sequence (PZS) comprised of a d(GC) n repeat was explored to determine whether oxidation in this motif was also a transcriptional switch. Bioinformatic analysis found 1650 PZSs of length >10 nts in the human genome that were overrepresented in promoters and 5'-UTRs. Studies in human cells transfected with a luciferase reporter plasmid in which OG was synthesized in a PZS context in the promoter found that a coding strand OG increased expression and a template strand OG decreased expression. The initial base excision repair product of OG, an abasic site (AP), was also found to yield similar expression changes as OG. Biophysical studies on model Z-DNA strands found OG favored a shift in the equilibrium to Z-DNA from B-DNA, while an AP disrupted Z-DNA to favor a hairpin, placing AP in the loop where it is a poor substrate for the endonuclease APE1. Overall, the impact of OG and AP in a PZS on gene expression was similar to that in a PQS but reduced in magnitude.


Assuntos
Adutos de DNA/metabolismo , DNA Forma Z/metabolismo , Expressão Gênica/fisiologia , Guanina/química , Regiões Promotoras Genéticas/fisiologia , Sequência de Bases , Linhagem Celular Tumoral , Adutos de DNA/química , Adutos de DNA/genética , DNA Forma Z/química , DNA Forma Z/genética , Quadruplex G , Genoma/fisiologia , Guanina/análogos & derivados , Humanos , Oxirredução , Estresse Oxidativo/genética
13.
Dev Dyn ; 248(5): 363-374, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30843624

RESUMO

BACKGROUND: Numerous pathologies of pregnancy originate from placental dysfunction. It is essential to understand the functions of key genes in the placenta in order to discern the etiology of placental pathologies. A paucity of animal models that allow conditional and inducible expression of a target gene in the placenta is a major limitation for studying placental development and function. RESULTS: To study the platelet-derived growth factor receptor alpha (PDGFRα)-directed and tamoxifen-induced Cre recombinase expression in the placenta, PDGFRα-CreER mice were crossed with mT/mG dual-fluorescent reporter mice. The expression of endogenous membrane-localized enhanced green fluorescent protein (mEGFP) and/or dTomato in the placenta was examined to identify PDGFRα promoter-directed Cre expression. Pregnant PDGFRα-CreER;mT/mG mice were treated with tamoxifen at various gestational ages. Upon tamoxifen treatment, reporter protein mEGFP was observed in the junctional zone (JZ) and chorionic plate (CP). Furthermore, a single dose of tamoxifen was sufficient to induce the recombination. CONCLUSIONS: PDGFRα-CreER expression is restricted to the JZ and CP of mouse placentas. PDGFRα-CreER mice provide a useful tool to conditionally knock out or overexpress a target gene in these regions of the mouse placenta.


Assuntos
Integrases/metabolismo , Placenta/metabolismo , Regiões Promotoras Genéticas/fisiologia , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Animais , Feminino , Camundongos , Gravidez , Recombinação Genética , Tamoxifeno/farmacologia
14.
PLoS One ; 14(3): e0212678, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30908494

RESUMO

In higher eukaryotes, gene architecture and structural properties of promoters have emerged as significant factors influencing variation in number of transcripts (expression level) and specificity of gene expression in a tissue (expression breadth), which eventually shape the phenotype. In this study, transcriptome data of different tissue types at various developmental stages of A. thaliana, O. sativa, S. bicolor and Z. mays have been used to understand the relationship between properties of gene components and its expression. Our findings indicate that in plants, among all gene architecture and structural properties of promoters, compactness of genes in terms of intron content is significantly linked to gene expression level and breadth, whereas in human an exactly opposite scenario is seen. In plants, for the first time we have carried out a quantitative estimation of effect of a particular trait on expression level and breadth, by using multiple regression analysis and it confirms that intron content of primary transcript (as %) is a powerful determinant of expression breadth. Similarly, further regression analysis revealed that among structural properties of the promoters, stability is negatively linked to expression breadth, while DNase1 sensitivity strongly governs gene expression breadth in monocots and gene expression level in dicots. In addition, promoter regions of tissue specific genes are found to be enriched with TATA box and Y-patch motifs. Finally, multi copy orthologous genes in plants are found to be longer, highly regulated and tissue specific.


Assuntos
Regulação da Expressão Gênica de Plantas/fisiologia , Plantas/metabolismo , Regiões Promotoras Genéticas/fisiologia , Plantas/genética
15.
Plant Physiol Biochem ; 139: 161-170, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30897507

RESUMO

Soil salinization is a major abiotic stress condition that affects about half of global agricultural lands. Salinity leads to osmotic shock, ionic imbalance and/or toxicity and build-up of reactive oxygen species. Na⁺/H⁺ antiporters (NHXs) are integral membrane transporters that catalyze the electro-neutral exchange of K⁺/Na⁺ for H⁺ and are implicated in cell expansion, development, pH/ion homeostasis and salt tolerance. Porteresia coarctata is a salt secreting halophytic wild rice that thrives in the coastal-riverine interface. P. coarctata NHX1 (PcNHXI) expression is induced by salinity in P. coarctata roots and shows high sequence identity to Oryza sativa NHX1. PcNHX1 confers hygromycin and Li+ sensitivity and Na+ tolerance transport in a yeast strain lacking sodium transport systems. Additionally, transgenic PcNHX1 expressing tobacco seedlings (PcNHX1 promoter) show significant growth advantage under increasing concentrations of NaCl and MS salts. Etiolated PcNHX1 seedlings also exhibit significantly elongated hypocotyl lengths in 100 mM NaCl. PcNHX1 expression in transgenic tobacco roots increases under salinity, similar to expression in P. coarctata roots. Under incremental salinity, transgenic lines show reduction in leaf Na+, stem specific accumulation of Na+ and K+ (unaltered Na+/K+ ratios). PcNHX1 transgenic plants also show enhanced chlorophyll content and reduced malondialdehyde (MDA) production in leaves under salinity. The above data suggests that PcNHX1 overexpression (controlled by PcNHX1p) enhances stem specific accumulation of Na+, thereby protecting leaf tissues from salt induced injury.


Assuntos
Hipocótilo/crescimento & desenvolvimento , Proteínas de Plantas/genética , Caules de Planta/metabolismo , Poaceae/genética , Trocadores de Sódio-Hidrogênio/genética , Sódio/metabolismo , Clorofila/metabolismo , Genes de Plantas/genética , Genes de Plantas/fisiologia , Malondialdeído/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Poaceae/fisiologia , Regiões Promotoras Genéticas/genética , Regiões Promotoras Genéticas/fisiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/fisiologia , Plantas Tolerantes a Sal/genética , Plantas Tolerantes a Sal/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Trocadores de Sódio-Hidrogênio/fisiologia , Tabaco
16.
PLoS One ; 14(3): e0212630, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30845225

RESUMO

It has been widely recognized that the early or delayed puberty appears to display harmful effects on adult health outcomes. During the timing of puberty, pituitaries responds to the hypothalamus and then introduce the following response of ovaries in hypothalamic-pituitary-gonadal axis. DNA methylation has been recently suggested to regulate the onset of puberty in female mammals. However, to date, the changes of DNA methylation in pituitaries have not been investigated during pubertal transition. In this study, using gilts as the pubertal model, the genome-scale DNA methylation of pituitaries was profiled and compared across Pre-, In- and Post-puberty by using the reduced representation bisulfite sequencing. We found that average methylation levels of each genomic feature in Post- were lower than Pre- and In-pubertal stage in CpG context, but they were higher in In- than that in Pre- and Post-pubertal stage in CpH (where H = A, T, or C) context. The methylation patterns of CpHs were more dynamic than that of CpGs at the location of high CpG content, low CpG content promoter genes, and differently genomic CGIs. Furthermore, the differently genomic CGIs were likely to show in a similar manner in CpG context but display in a stage-specific manner in the CpH context across the Pre-, In- and Post-pubertal stage. Among these pubertal stages, 5 kb upstream regions of the transcription start sites were protected from both CpG and CpH methylation changes. 12.65% of detected CpGs were identified as the differentially methylated CpGs, regarding 4301 genes which were involved in the fundamental functions of pituitaries. 0.35% of detected CpHs were identified as differentially methylated CpHs, regarding 3691 genes which were involved in the biological functions of releasing gonadotropin hormones. These observations and analyses would provide valuable insights into epigenetic mechanism of the initiation of puberty in pituitary level.


Assuntos
Ilhas de CpG/fisiologia , Metilação de DNA/fisiologia , Epigênese Genética/fisiologia , Hipófise/metabolismo , Regiões Promotoras Genéticas/fisiologia , Maturidade Sexual/fisiologia , Animais , Feminino , Estudo de Associação Genômica Ampla , Suínos
17.
Drug Metab Dispos ; 47(5): 444-452, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30819787

RESUMO

Accurate quantification of the metabolic enzyme uridine diphospho-glucuronosyltransferase (UGT) UGT2B17 has been hampered by the high sequence identity with other UGT2B enzymes (as high as 94%) and by the lack of a specific antibody. Knowing the significance of the UGT2B17 pathway in drug and hormone metabolism and cancer, we developed a specific monoclonal antibody (EL-2B17mAb), initially validated by the lack of detection in liver microsomes of an individual carrying no UGT2B17 gene copy and in supersomes expressing UGT2B enzymes. Immunohistochemical detection in livers revealed strong labeling of bile ducts and variable labeling of hepatocytes. Expression levels assessed by immunoblotting were highly correlated to mass spectrometry-based quantification (r = 0.93), and three major expression patterns (absent, low, or high) were evidenced. Livers with very low expression were carriers of the functional rs59678213 G variant, located in the binding site for the transcription factor forkhead box A1 (FOXA1) of the UGT2B17 promoter. The highest level of expression was observed for individuals carrying at least one rs59678213 A allele. Multiple regression analysis indicated that the number of gene copies explained only 8% of UGT2B17 protein expression, 49% when adding rs59678213, reaching 54% when including sex. The novel EL-2B17mAb antibody allowed specific UGT2B17 quantification and exposed different patterns of hepatic expression. It further suggests that FOXA1 is a key driver of UGT2B17 expression in the liver. The availability of this molecular tool will help characterize the UGT2B17 level in various disease states and establish more precisely the contribution of the UGT2B17 enzyme to drug and hormone metabolism.


Assuntos
Anticorpos Monoclonais/metabolismo , Glucuronosiltransferase/metabolismo , Fígado/metabolismo , Microssomos Hepáticos/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Sítios de Ligação , Regulação da Expressão Gênica/fisiologia , Humanos , Regiões Promotoras Genéticas/fisiologia
18.
PLoS Comput Biol ; 15(2): e1006784, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30779734

RESUMO

Phenotypical variability in the absence of genetic variation often reflects complex energetic landscapes associated with underlying gene regulatory networks (GRNs). In this view, different phenotypes are associated with alternative states of complex nonlinear systems: stable attractors in deterministic models or modes of stationary distributions in stochastic descriptions. We provide theoretical and practical characterizations of these landscapes, specifically focusing on stochastic Slow Promoter Kinetics (SPK), a time scale relevant when transcription factor binding and unbinding are affected by epigenetic processes like DNA methylation and chromatin remodeling. In this case, largely unexplored except for numerical simulations, adiabatic approximations of promoter kinetics are not appropriate. In contrast to the existing literature, we provide rigorous analytic characterizations of multiple modes. A general formal approach gives insight into the influence of parameters and the prediction of how changes in GRN wiring, for example through mutations or artificial interventions, impact the possible number, location, and likelihood of alternative states. We adapt tools from the mathematical field of singular perturbation theory to represent stationary distributions of Chemical Master Equations for GRNs as mixtures of Poisson distributions and obtain explicit formulas for the locations and probabilities of metastable states as a function of the parameters describing the system. As illustrations, the theory is used to tease out the role of cooperative binding in stochastic models in comparison to deterministic models, and applications are given to various model systems, such as toggle switches in isolation or in communicating populations, a synthetic oscillator, and a trans-differentiation network.


Assuntos
Biologia Computacional/métodos , Redes Reguladoras de Genes/fisiologia , Regiões Promotoras Genéticas/fisiologia , Diferenciação Celular/genética , Simulação por Computador , Regulação da Expressão Gênica/fisiologia , Cinética , Modelos Biológicos , Modelos Genéticos , Fenótipo , Distribuição de Poisson , Probabilidade , Regiões Promotoras Genéticas/genética , Ligação Proteica , Processos Estocásticos , Transcrição Genética/genética
19.
Plant Cell ; 31(2): 430-443, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30712008

RESUMO

Leaf senescence is governed by a complex regulatory network involving the dynamic reprogramming of gene expression. Age-dependent induction of senescence-associated genes (SAGs) is associated with increased levels of trimethylation of histone H3 at Lys4 (H3K4me3), but the regulatory mechanism remains elusive. Here, we found that JMJ16, an Arabidopsis (Arabidopsis thaliana) JmjC-domain containing protein, is a specific H3K4 demethylase that negatively regulates leaf senescence through its enzymatic activity. Genome-wide analysis revealed a widespread coordinated upregulation of gene expression and hypermethylation of H3K4me3 at JMJ16 binding genes associated with leaf senescence in the loss-of-function jmj16 mutant as compared with the wild type. Genetic analysis indicated that JMJ16 negatively regulates leaf senescence, at least partly through repressing the expression of positive regulators of leaf senescence, WRKY53 and SAG201 JMJ16 associates with WRKY53 and SAG201 and represses their precocious expression in mature leaves by reducing H3K4me3 levels at these loci. The protein abundance of JMJ16 gradually decreases during aging, which is correlated with increased H3K4me3 levels at WRKY53 and SAG201, suggesting that the age-dependent downregulation of JMJ16 is required for the precise transcriptional activation of SAGs during leaf senescence. Thus, JMJ16 is an important regulator of leaf senescence that demethylates H3K4 at SAGs in an age-dependent manner.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Folhas de Planta/genética , Plantas Geneticamente Modificadas/genética , Regiões Promotoras Genéticas/genética , Regiões Promotoras Genéticas/fisiologia , Fatores de Transcrição/genética
20.
Clin Biochem ; 66: 100-102, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30753843

RESUMO

OBJECTIVES: Elevated levels of metabolites such as ammonia and propionylcarnitine in propionic acidemia (PA) lead to an increased reactive oxygen species (ROS) production which could activate and stabilize the epigenetic regulated hypoxia-inducible factor-1α (HIF-1α). In order to evaluate the DNA methylation status of the HIF-1α binding site in PA, we investigated the antioxidant gluthatione peroxidase 3 gene (GPX3) promoter region. DESIGN AND METHODS: Using leukocyte DNA extracted from bloodspots collected 2-4 days after birth from diet free newborns, the cytosine phosphodiester bond guanine (CpG) dinucleotides of a HIF-1α binding site (CGTTTTTTACG) in the promoter region of GPX3 was retrospectively analysed. Patients included 7 PA. and 7 healthy controls (KO) respectively. RESULTS: A demethylated TGTTTTTTATG allele was detected in 3 PA patients with blood ammonia (NH3) concentrations of 500, 595, and 987 umol/L respectively; a demethylated/partial methylated TGTTTTTTAC/TG allele in 4 PA patients (2 PA with blood NH3 = 213, 271 umol/L respectively); a partial methylated C/TGTTTTTTAC/TG allele in 5 healthy controls respectively; a partial methylated/methylated C/TGTTTTTTACG allele in 2 healthy controls. CONCLUSION: Our results suggest that at excess NH3, the DNA methylation status of the HIF-1α binding site of GPX3 in newborns with PA is demethylated (TGTTTTTTATG allele). However, the demethylated allele has to be confirmed as a statistically significant change in more patients.


Assuntos
Amônia/metabolismo , Metilação de DNA/fisiologia , Glutationa Peroxidase/genética , Hiperamonemia/fisiopatologia , Acidemia Propiônica/fisiopatologia , Sítios de Ligação/fisiologia , Desmetilação , Humanos , Recém-Nascido , Regiões Promotoras Genéticas/fisiologia
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