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1.
J Biol Chem ; 294(10): 3563-3576, 2019 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-30630953

RESUMO

Plants produce various l-tyrosine (Tyr)-derived compounds that are critical for plant adaptation and have pharmaceutical or nutritional importance for human health. Tyrosine aminotransferases (TATs) catalyze the reversible reaction between Tyr and 4-hydroxyphenylpyruvate (HPP), representing the entry point in plants for both biosynthesis of various natural products and Tyr degradation in the recycling of energy and nutrients. To better understand the roles of TATs and how Tyr is metabolized in planta, here we characterized single and double loss-of-function mutants of TAT1 (At5g53970) and TAT2 (At5g36160) in the model plant Arabidopsis thaliana As reported previously, tat1 mutants exhibited elevated and decreased levels of Tyr and tocopherols, respectively. The tat2 mutation alone had no impact on Tyr and tocopherol levels, but a tat1 tat2 double mutant had increased Tyr accumulation and decreased tocopherol levels under high-light stress compared with the tat1 mutant. Relative to WT and the tat2 mutant, the tat1 mutant displayed increased vulnerability to continuous dark treatment, associated with an early drop in respiratory activity and sucrose depletion. During isotope-labeled Tyr feeding in the dark, we observed that the tat1 mutant exhibits much slower 13C incorporation into tocopherols, fumarate, and other tricarboxylic acid (TCA) cycle intermediates than WT and the tat2 mutant. These results indicate that TAT1 and TAT2 function together in tocopherol biosynthesis, with TAT2 having a lesser role, and that TAT1 plays the major role in Tyr degradation in planta Our study also highlights the importance of Tyr degradation under carbon starvation conditions during dark-induced senescence in plants.


Assuntos
Arabidopsis/metabolismo , Tirosina Transaminase/metabolismo , Tirosina/metabolismo , Arabidopsis/citologia , Arabidopsis/enzimologia , Arabidopsis/genética , Carbono/metabolismo , Ciclo do Ácido Cítrico , Citosol/metabolismo , Metabolismo Energético , Mutação , Tocoferóis/metabolismo , Tirosina Transaminase/genética
2.
Bull Exp Biol Med ; 165(4): 474-477, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30121910

RESUMO

The glucocorticoid status and activities of ALT, AST, and tyrosine aminotransferase in the liver are studied in rats with streptozotocin-induced diabetes mellitus in response to repeated intraperitoneal injections of mifepristone. Diabetic rats develop an increase of the blood corticosterone and liver aminotransferase levels in response to mifepristone. These results indicate that in diabetic animals the glucocorticoid hormones with high blood concentrations, increasing still more in response to mifepristone, overcome the receptor blockade, and realize their regulatory functions in hepatocytes. The effects of mifepristone on ALT activity are the most manifest. In normal rats, only ALT activity is increasing in response to mifepristone, while in rats with streptozotocin-induced diabetes mellitus, ALT activity increases more intensely than activities of tyrosine aminotransferase and AST.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Mifepristona/uso terapêutico , Alanina Transaminase/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Glicemia/efeitos dos fármacos , Corticosterona/sangue , Diabetes Mellitus Experimental/sangue , Glucocorticoides/sangue , Masculino , Ratos , Ratos Wistar , Tirosina Transaminase/metabolismo
3.
J Eukaryot Microbiol ; 65(1): 70-76, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28618210

RESUMO

Trypanosoma cruzi, the etiological agent of Chagas disease, lacks genes that encode canonical branched-chain aminotransferases. However, early studies showed that when epimastigotes were grown in the presence of 14 C1 -DL-leucine, the label was incorporated into various intermediates. More recently, our studies provided evidence that T. cruzi epimastigotes display a single ATP-dependent and saturable transport system that enables epimastigotes to uptake branched-chain amino acids (BCAAs) from the culture media. To extend our knowledge of the first step of BCAA catabolism, the ability of this parasite's noncanonical broad specificity aminotransferases, such as tyrosine aminotransferase (TAT) and aspartate aminotransferase (ASAT), to transaminate these amino acids was investigated. Indeed, our results show that TAT and ASAT utilize BCAAs as substrates; however, both enzymes differ in their catalytic competence in utilizing these amino donors. For instance, ASAT transaminates isoleucine nearly 10-fold more efficiently than does TAT. This unique characteristic of TAT and ASAT allows to explain how BCAAs can be oxidized in the absence of a BCAA transaminase in T. cruzi.


Assuntos
Aspartato Aminotransferases/metabolismo , Proteínas de Protozoários/metabolismo , Trypanosoma cruzi/enzimologia , Tirosina Transaminase/metabolismo , Aminoácidos de Cadeia Ramificada/metabolismo
4.
J Agric Food Chem ; 65(50): 11054-11064, 2017 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-29121768

RESUMO

Tocopherols composed of four isoforms (α, ß, γ, and δ) and its biosynthesis comprises of three pathways: methylerythritol 4-phosphate (MEP), shikimate (SK) and tocopherol-core pathways regulated by 25 enzymes. To understand pathway regulatory mechanism at transcriptional level, gene expression profile of tocopherol-biosynthesis genes in two soybean genotypes was carried out, the results showed significantly differential expression of 5 genes: 1-deoxy-d-xylulose-5-P-reductoisomerase (DXR), geranyl geranyl reductase (GGDR) from MEP, arogenate dehydrogenase (TyrA), tyrosine aminotransferase (TAT) from SK and γ-tocopherol methyl transferase 3 (γ-TMT3) from tocopherol-core pathways. Expression data were further analyzed for total tocopherol (T-toc) and α-tocopherol (α-toc) content by coregulation network and gene clustering approaches, the results showed least and strong association of γ-TMT3/tocopherol cyclase (TC) and DXR/DXS, respectively, with gene clusters of tocopherol biosynthesis suggested the specific role of γ-TMT3/TC in determining tocopherol accumulation and intricacy of DXR/DXS genes in coordinating precursor pathways toward tocopherol biosynthesis in soybean seeds. Thus, the present study provides insight into the major role of these genes regulating the tocopherol synthesis in soybean seeds.


Assuntos
Proteínas de Plantas/genética , Soja/genética , Tocoferóis/metabolismo , Transcrição Genética , Vias Biossintéticas , Regulação da Expressão Gênica de Plantas , Genótipo , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Prefenato Desidrogenase/genética , Prefenato Desidrogenase/metabolismo , Sementes/química , Sementes/enzimologia , Sementes/genética , Sementes/metabolismo , Soja/química , Soja/enzimologia , Soja/metabolismo , Tocoferóis/química , Transferases/genética , Transferases/metabolismo , Tirosina Transaminase/genética , Tirosina Transaminase/metabolismo
5.
Biomed Khim ; 63(3): 266-271, 2017 May.
Artigo em Russo | MEDLINE | ID: mdl-28781260

RESUMO

The content of the amino acids in the placenta during physiological pregnancy and fetal growth restriction (FGR) has been investigated my means of the method of ion-exchange chromatography. It has been found that in FGR the placental amino acid pool is characterized by a decreased content of arginine, proline, alanine, serine, cysteine, methionine, tryptophan, leucine, threonine, tyrosine, phenylalanine, glutamine and an increased content of dicarboxylic amino acids, lysine, histidine and glycine. These changes are accompanied by altered activity of some enzymes of amino acid metabolism, and the degree of these changes correlates with the level of corresponding amino acids.


Assuntos
Aminoácidos/metabolismo , Retardo do Crescimento Fetal/metabolismo , Recém-Nascido de Baixo Peso , Placenta/metabolismo , Adulto , Alanina Transaminase/metabolismo , Arginase/metabolismo , Aspartato Aminotransferases/metabolismo , Estudos de Casos e Controles , Feminino , Desenvolvimento Fetal/fisiologia , Retardo do Crescimento Fetal/patologia , Glutamato Sintase/metabolismo , Homeostase , Humanos , Recém-Nascido , Troca Materno-Fetal/fisiologia , Placenta/química , Placenta/patologia , Gravidez , Transaminases/metabolismo , Tirosina Transaminase/metabolismo
6.
Sci Rep ; 7(1): 4892, 2017 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-28687763

RESUMO

Rosmarinic acid (RA) and its derivants are medicinal compounds that comprise the active components of several therapeutics. We isolated and characterised a tyrosine aminotransferase of Prunella vulgaris (PvTAT). Deduced PvTAT was markedly homologous to other known/putative plant TATs. Cytoplasmic localisation of PvTAT was observed in tobacco protoplasts. Recombinantly expressed and purified PvTAT had substrates preference for L-tyrosine and phenylpyruvate, with apparent K m of 0.40 and 0.48 mM, and favoured the conversion of tyrosine to 4-hydroxyphenylpyruvate. In vivo activity was confirmed by functional restoration of the Escherichia coli tyrosine auxotrophic mutant DL39. Agrobacterium rhizogenes-mediated antisense/sense expression of PvTAT in hairy roots was used to evaluate the contribution of PvTAT to RA synthesis. PvTAT were reduced by 46-95% and RA were decreased by 36-91% with low catalytic activity in antisense transgenic hairy root lines; furthermore, PvTAT were increased 0.77-2.6-fold with increased 1.3-1.8-fold RA and strong catalytic activity in sense transgenic hairy root lines compared with wild-type counterparts. The comprehensive physiological and catalytic evidence fills in the gap in RA-producing plants which didn't provide evidence for TAT expression and catalytic activities in vitro and in vivo. That also highlights RA biosynthesis pathway in P. vulgaris and provides useful information to engineer natural products.


Assuntos
Anti-Inflamatórios não Esteroides/metabolismo , Cinamatos/metabolismo , Depsídeos/metabolismo , Prunella/enzimologia , Prunella/metabolismo , Tirosina Transaminase/metabolismo , Agrobacterium/genética , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Inativação Gênica , Teste de Complementação Genética , Cinética , Ácidos Fenilpirúvicos/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Transformação Genética , Tirosina/metabolismo , Tirosina Transaminase/química , Tirosina Transaminase/isolamento & purificação
7.
Phytochemistry ; 132: 16-25, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27726859

RESUMO

Plants produce various L-tyrosine (Tyr)-derived compounds that are of pharmaceutical or nutritional importance to humans. Tyr aminotransferase (TAT) catalyzes the reversible transamination between Tyr and 4-hydroxyphenylpyruvate (HPP), the initial step in the biosynthesis of many Tyr-derived plant natural products. Herein reported is the biochemical characterization and subcellular localization of TAT enzymes from the model plant Arabidopsis thaliana. Phylogenetic analysis showed that Arabidopsis has at least two homologous TAT genes, At5g53970 (AtTAT1) and At5g36160 (AtTAT2). Their recombinant enzymes showed distinct biochemical properties: AtTAT1 had the highest activity towards Tyr, while AtTAT2 exhibited a broad substrate specificity for both amino and keto acid substrates. Also, AtTAT1 favored the direction of Tyr deamination to HPP, whereas AtTAT2 preferred transamination of HPP to Tyr. Subcellular localization analysis using GFP-fusion proteins and confocal microscopy showed that AtTAT1, AtTAT2, and HPP dioxygenase (HPPD), which catalyzes the subsequent step of TAT, are localized in the cytosol, unlike plastid-localized Tyr and tocopherol biosynthetic enzymes. Furthermore, subcellular fractionation indicated that, while HPPD activity is restricted to the cytosol, TAT activity is detected in both cytosolic and plastidic fractions of Arabidopsis leaf tissue, suggesting that an unknown aminotransferase(s) having TAT activity is also present in the plastids. Biochemical and cellular analyses of Arabidopsis TATs provide a fundamental basis for future in vivo studies and metabolic engineering for enhanced production of Tyr-derived phytochemicals in plants.


Assuntos
Arabidopsis , Tirosina Transaminase/metabolismo , Tirosina/metabolismo , Arabidopsis/química , Arabidopsis/enzimologia , Arabidopsis/genética , Dioxigenases/metabolismo , Humanos , Cinética , Estrutura Molecular , Ácidos Fenilpirúvicos , Filogenia , Folhas de Planta/metabolismo , Plastídeos/metabolismo , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Transaminases/metabolismo
8.
Curr Biol ; 26(16): 2188-93, 2016 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-27476595

RESUMO

Blood-feeding arthropods are vectors of infectious diseases such as dengue, Zika, Chagas disease, and malaria [1], and vector control is essential to limiting disease spread. Because these arthropods ingest very large amounts of blood, a protein-rich meal, huge amounts of amino acids are produced during digestion. Previous work on Rhodnius prolixus, a vector of Chagas disease, showed that, among all amino acids, only tyrosine degradation enzymes were overexpressed in the midgut compared to other tissues [2]. Here we demonstrate that tyrosine detoxification is an essential trait in the life history of blood-sucking arthropods. We found that silencing Rhodnius tyrosine aminotransferase (TAT) and 4-hydroxyphenylpyruvate dioxygenase (HPPD), the first two enzymes of the phenylalanine/tyrosine degradation pathway, caused the death of insects after a blood meal. This was confirmed by using the HPPD inhibitor mesotrione, which selectively killed hematophagous arthropods but did not affect non-hematophagous insects. In addition, mosquitoes and kissing bugs died after feeding on mice that had previously received a therapeutic effective oral dose (1 mg/kg) of nitisinone, another HPPD inhibitor used in humans for the treatment of tyrosinemia type I [3]. These findings indicate that HPPD (and TAT) can be a target for the selective control of blood-sucking disease vector populations. Because HPPD inhibitors are extensively used as herbicides and in medicine, these compounds may provide an alternative less toxic to humans and more environmentally friendly than the conventional neurotoxic insecticides that are currently used, with the ability to affect only hematophagous arthropods.


Assuntos
4-Hidroxifenilpiruvato Dioxigenase/genética , Inativação Gênica , Proteínas de Insetos/genética , Rhodnius/genética , Tirosina Transaminase/genética , Tirosina/metabolismo , 4-Hidroxifenilpiruvato Dioxigenase/metabolismo , Animais , Feminino , Inativação Metabólica , Proteínas de Insetos/metabolismo , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Ninfa/metabolismo , Rhodnius/crescimento & desenvolvimento , Rhodnius/metabolismo , Tirosina Transaminase/metabolismo
9.
Diabetes ; 65(10): 3075-90, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27411382

RESUMO

MicroRNAs (miRNAs) have a fundamental role in diabetic heart failure. The cardioprotective miRNA-133a (miR-133a) is downregulated, and contractility is decreased in diabetic hearts. Norepinephrine (NE) is a key catecholamine that stimulates contractility by activating ß-adrenergic receptors (ß-AR). NE is synthesized from tyrosine by the rate-limiting enzyme, tyrosine hydroxylase (TH), and tyrosine is catabolized by tyrosine aminotransferase (TAT). However, the cross talk/link between TAT and TH in the heart is unclear. To determine whether miR-133a plays a role in the cross talk between TH and TAT and regulates contractility by influencing NE biosynthesis and/or ß-AR levels in diabetic hearts, Sprague-Dawley rats and miR-133a transgenic (miR-133aTg) mice were injected with streptozotocin to induce diabetes. The diabetic rats were then treated with miR-133a mimic or scrambled miRNA. Our results revealed that miR-133a mimic treatment improved the contractility of the diabetic rat's heart concomitant with upregulation of TH, cardiac NE, ß-AR, and downregulation of TAT and plasma levels of NE. In miR-133aTg mice, cardiac-specific miR-133a overexpression prevented upregulation of TAT and suppression of TH in the heart after streptozotocin was administered. Moreover, miR-133a overexpression in CATH.a neuronal cells suppressed TAT with concomitant upregulation of TH, whereas knockdown and overexpression of TAT demonstrated that TAT inhibited TH. Luciferase reporter assay confirmed that miR-133a targets TAT. In conclusion, miR-133a controls the contractility of diabetic hearts by targeting TAT, regulating NE biosynthesis, and consequently, ß-AR and cardiac function.


Assuntos
MicroRNAs/metabolismo , Contração Miocárdica/fisiologia , Miocárdio/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Tirosina Transaminase/metabolismo , Animais , Western Blotting , Diabetes Mellitus Experimental/metabolismo , Células HEK293 , Hemodinâmica/fisiologia , Humanos , Imuno-Histoquímica , Masculino , Camundongos Transgênicos , MicroRNAs/genética , MicroRNAs/fisiologia , Contração Miocárdica/genética , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Norepinefrina/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Adrenérgicos beta/genética , Receptores Adrenérgicos beta/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tirosina 3-Mono-Oxigenase/genética , Tirosina Transaminase/genética
10.
Sheng Wu Gong Cheng Xue Bao ; 32(2): 222-30, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-27382772

RESUMO

To investigate roles of nitric oxide (NO) signal in accumulations of phenolic acids in abscisic.acid (ABA)-induced Salvia miltiorrhiza hairy roots, S. miltiorrhiza hairy roots were treated with different concentrations of sodium nitroprusside (SNP)-an exogenous NO donor, for 6 days, and contents of phenolic acids in the hairy roots are determined. Then with treatment of ABA and NO scavenger (2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1- oxyl-3-oxide, c-PTIO) or NO synthase inhibitor (NG-nitro-L-arginine methyl ester, L-NAME), contents of phenolic acids and expression levels of three key genes involved in phenolic acids biosynthesis were detected. Phenolic acids production in S. miltiorrhiza hairy roots was most significantly improved by 100 µmoL/L SNP. Contents of RA and salvianolic acid B increased by 3 and 4 folds. ABA significantly improved transcript levels of PAL (phenylalanine ammonia lyase), TAT (tyrosine aminotransferase) and RAS (rosmarinic acid synthase), and increased phenolic acids accumulations. However, with treatments of ABA+c-PTIO or ABA+L-NAME, accumulations of phenolic acids and expression levels of the three key genes were significantly inhibited. Both NO and ABA can increase accumulations of phenolic acids in S. miltiorrhiza hairy roots. NO signal probably mediates the ABA-induced phenolic acids production.


Assuntos
Ácido Abscísico/farmacologia , Hidroxibenzoatos/metabolismo , Óxido Nítrico/metabolismo , Raízes de Plantas/metabolismo , Salvia miltiorrhiza/metabolismo , Benzofuranos/metabolismo , Depuradores de Radicais Livres/farmacologia , Fenilalanina Amônia-Liase/metabolismo , Tirosina Transaminase/metabolismo
11.
Domest Anim Endocrinol ; 57: 10-20, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27295280

RESUMO

Tyrosine aminotransferase (TAT) catalyzes the transamination of tyrosine to p-hydroxyphenylpyruvate. Accumulation of tyrosine in the body due to a genetic mutation in the TAT gene causes tyrosomia type II in humans. The TAT gene is regarded as a model for studying steroid-inducible factors regulating a variety of biological functions of TAT. However, little is known of the effects of estrogen on the expression of the TAT gene in chickens. Therefore, in the present study, we identified expression of the avian TAT gene in various organs. The results showed the TAT was detected predominantly in the liver and reproductive organs including testis, oviduct, and ovary. Specifically, TAT mRNA was expressed abundantly in the glandular and luminal epithelia of the oviducts in response to endogenous and exogenous estrogens which also induce dramatic morphological changes in the oviduct of chickens. In addition, target microRNAs of TAT (miR-1460, miR-1626-3p, miR-1690-5p, and miR-7442-3p) were found to modulate expression of the TAT gene. Especially, miR-1690-5p influenced TAT gene transcription by binding directly to its 3'-UTR region. Moreover, the expression of TAT was abundant in glandular epithelia of cancerous but not normal ovaries from laying hens. Taken together, our findings suggest that TAT plays an important role in the cytodifferentiation of oviducts in response to estrogen and in the progression of ovarian cancer in chickens.


Assuntos
Galinhas/metabolismo , Estrogênios/metabolismo , Regulação Enzimológica da Expressão Gênica/fisiologia , Oviductos/enzimologia , Tirosina Transaminase/metabolismo , Envelhecimento , Sequência de Aminoácidos , Animais , Estrogênios/sangue , Feminino , MicroRNAs , Muda , Oviductos/metabolismo , Distribuição Tecidual , Tirosina Transaminase/genética
12.
Pediatr Int ; 58(10): 1069-1072, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27285949

RESUMO

Tyrosinemia type II is a rare autosomal recessive disorder caused by deficiency of tyrosine aminotransferase (TAT). It may occur with ocular and cutaneous symptoms with or without mental retardation, but epileptic seizure is a rare presentation of this disease. Herein we report the clinical, biochemical and genetic features of a 4-year-old boy who presented with afebrile seizure and photophobia. Genomic DNA was obtained from peripheral blood leukocytes from the whole family. Sequencing analysis was performed using the MiSeq next-generation sequencing platform. Sequencing of TAT indicated two new homozygous mutations p.L312P (c.935T>C) and p.T408M (c.1223C>T) for the proband and his asymptomatic sister. During a 2 year follow-up period, the patient had overall poor compliance with protein-restricted diet, but his asymptomatic sister had good compliance with the diet. Cognitive function of the patient worsened steadily, but his asymptomatic sister maintained normal mental status. Tyrosinemia type II should be considered in the differential diagnosis of children presenting with epileptic seizure and photophobia; furthermore, early diagnosis and protein-restricted regimen are important to reduce the risk of long-term complications of tyrosinemia type II such as mental disability.


Assuntos
DNA/genética , Mutação , Tirosina Transaminase/genética , Tirosinemias/genética , Pré-Escolar , Análise Mutacional de DNA , Homozigoto , Humanos , Masculino , Linhagem , Tirosina Transaminase/metabolismo , Tirosinemias/enzimologia
13.
Mol Med Rep ; 12(2): 2872-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25975647

RESUMO

5-azacytidine (5-azaC) is known to induce cardiomyocyte differentiation. However, its function in hepatocyte differentiation is unclear. The present study investigated the in vitro capability of 5-azaC to promote maturation and differentiation of mouse embryonic hepatic progenitor cells, with the aim of developing an approach for improving hepatic differentiation. Mouse embryonic hepatic progenitor cells (HP14.5 cells) were treated with 5-azaC at concentrations from 0 to 20 µmol/l, in addition to hepatocyte induction culture medium. Hepatocyte induction medium induces HP14.5 cell differentiation. 5-azaC may enhance the albumin promotor-driven Gaussia luciferase (ALB-GLuc) activity in induced HP14.5 cells. In the present study 2 µmol/l was found to be the optimum concentration with which to achieve this. The expression of hepatocyte-associated factors was not significantly different between the group treated with 5-azaC alone and the control group. The mRNA levels of ALB; cytokeratin 18 (CK18); tyrosine aminotransferase (TAT); and cytochrome p450, family 1, member A1 (CYP1A1); in addition to the protein levels of ALB, CK18 and uridine diphosphate glucuronyltransferase 1A (UGT1A) in the induced group with 5-azaC, were higher than those in the induced group without 5-azaC, although no significant differences were detected in expression of the hepatic stem cell markers, DLK and α-fetoprotein, between the two groups. Treatment with 5-azaC alone did not affect glycogen synthesis or indocyanine green (ICG) metabolic function in HP14.5 cells, although it significantly increased ICG uptake and periodic acid-Schiff-positive cell numbers amongst HP14.5 cells. Therefore, the present study demonstrated that treatment with 5-azaC alone exerted no effects on the maturation and differentiation of HP14.5 cells. However, 5-azaC exhibited a synergistic effect on the terminal differentiation of induced hepatic progenitor cells in association with a hepatic induction medium.


Assuntos
Azacitidina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Hepatócitos/citologia , Células-Tronco/citologia , Animais , Proteínas de Ligação ao Cálcio , Células Cultivadas , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Embrião de Mamíferos/citologia , Glucuronosiltransferase/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Queratina-18/genética , Queratina-18/metabolismo , Camundongos , RNA Mensageiro/metabolismo , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Tirosina Transaminase/genética , Tirosina Transaminase/metabolismo , alfa-Fetoproteínas/metabolismo
14.
Bull Exp Biol Med ; 158(6): 789-93, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25894779

RESUMO

PT/Y mice used for studies of the effects of mutagens are characterized by the absence of spontaneous tumors of the liver, but often develop these tumors in response to chronic oaminoazotoluene treatment. The level of glucocorticoid induction of adaptive hepatic enzyme tyrosine aminotransferase decreases by more than 70% 24 h after acute injection of o-aminoazotoluene to these animals. These mice can serve as a model for studies of the relationship between the effect of carcinogens on the regulation of activity of adaptive hepatic enzymes and their capacity to induce the development of liver tumors.


Assuntos
Glucocorticoides/farmacologia , Fígado/metabolismo , Tirosina Transaminase/metabolismo , o-Aminoazotolueno/toxicidade , Animais , Camundongos
15.
Enzyme Microb Technol ; 66: 1-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25248692

RESUMO

This study aimed to improve rosmarinic acid (RA) production in the whole plant culture of Solenostemon scutellarioides through elicitation with phytopathogenic fungi. Amongst selected fungi, Aternaria alternata caused significant elevation (p<0.05-0.01) in RA accumulation (∼1.3-1.6-fold) between 25 and 100 µg l(-1). However, elicitation at the dose of 50 µg l(-1) has been found to be most effective and intracellular RA content reached almost ∼1.6-fold (p<0.01) higher in day 7. Therefore, A. alternata (50 µg l(-1)) was selected for mechanism evaluation. A significant elevation of intercellular jasmonic acid was observed up to day 6 after elicitation with A. alternata (50 µg l(-1)). A significant increase in tissue H2O2 and lipid peroxidation coupled with depletion of antioxidant enzymes superoxide dismutase and catalase indicated augmented oxidative stress associated with biotic interaction. Preceding the elicitor-induced RA accumulation, a notable alteration in the specific activities of biosynthetic enzymes namely PAL and TAT was recorded, while, no significant change in the activities of RAS was observed. HPPR activity was slightly improved in elicited plant. Therefore, it could be concluded that A. alternata elicited the biosynthesis of rosmarinic acid via signal transduction through jasmonic acid coupled with elicitor induced oxidative stress and associated mechanism.


Assuntos
Cinamatos/metabolismo , Depsídeos/metabolismo , Fungos/patogenicidade , Lamiaceae/metabolismo , Lamiaceae/microbiologia , Alternaria/patogenicidade , Antioxidantes/metabolismo , Aspergillus niger/patogenicidade , Ciclopentanos/metabolismo , Fusarium/patogenicidade , Genes de Plantas , Lamiaceae/genética , Redes e Vias Metabólicas , Estresse Oxidativo , Oxilipinas/metabolismo , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transdução de Sinais , Tirosina Transaminase/genética , Tirosina Transaminase/metabolismo
16.
Mol Endocrinol ; 28(10): 1707-18, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25148457

RESUMO

Disturbances in amino acid metabolism are increasingly recognized as being associated with, and serving as prognostic markers for chronic human diseases, such as cancer or type 2 diabetes. In the current study, a quantitative metabolomics profiling strategy revealed global impairment in amino acid metabolism in mice deleted for the transcriptional coactivator steroid receptor coactivator (SRC)-1. Aberrations were hepatic in origin, because selective reexpression of SRC-1 in the liver of SRC-1 null mice largely restored amino acids concentrations to normal levels. Cistromic analysis of SRC-1 binding sites in hepatic tissues confirmed a prominent influence of this coregulator on transcriptional programs regulating amino acid metabolism. More specifically, SRC-1 markedly impacted tyrosine levels and was found to regulate the transcriptional activity of the tyrosine aminotransferase (TAT) gene, which encodes the rate-limiting enzyme of tyrosine catabolism. Consequently, SRC-1 null mice displayed low TAT expression and presented with hypertyrosinemia and corneal alterations, 2 clinical features observed in the human syndrome of TAT deficiency. A heterozygous missense variant of SRC-1 (p.P1272S) that is known to alter its coactivation potential, was found in patients harboring idiopathic tyrosinemia-like disorders and may therefore represent one risk factor for their clinical symptoms. Hence, we reinforce the concept that SRC-1 is a central factor in the fine orchestration of multiple pathways of intermediary metabolism, suggesting it as a potential therapeutic target that may be exploitable in human metabolic diseases and cancer.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Aminoácidos/metabolismo , Fígado/metabolismo , Coativador 1 de Receptor Nuclear/metabolismo , Transcrição Genética , Erros Inatos do Metabolismo dos Aminoácidos/genética , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Knockout , Coativador 1 de Receptor Nuclear/genética , Tirosina Transaminase/genética , Tirosina Transaminase/metabolismo
17.
Nat Prod Res ; 28(20): 1691-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25051064

RESUMO

The aim of this study was to employ precursor-feeding strategy for the improved production of rosmarinic acid (RA) in Solenostemon scutellarioides in vitro. The cultures were fed with precursors, namely l-phenylalanine (Phe), l-tyrosine (Tyr) and cucumber juice (CJ), at different concentrations. Phe (100 mg L(-1)) and Tyr (400 mg L(-1)) caused ∼1.5- and 2.1-fold increase in RA accumulation within 48 h. CJ (50 mg L(-1)) feeding displayed highest RA content (∼1.6-fold) in 72 h. In this study, we focused on the function of individual precursor on key enzymes involved in RA biosynthesis. The phenylalanine ammonia lyase activity was significantly upregulated after Phe (100 mg L(-1)) feeding, while tyrosine aminotransferase and hydroxyphenylpyruvate reductase activities were improved with Tyr (400 mg L(-1)) treatment. However, rosmarinic acid synthase activity was significantly enhanced by all three precursors. In synergy study, Phe (100 mg L(-1)) + Tyr (400 mg L(-1)) could enhance (∼3.1-fold) RA biosynthesis within 48 h.


Assuntos
Cinamatos/metabolismo , Depsídeos/metabolismo , Lamiaceae/metabolismo , Meios de Cultura/química , Oxirredutases/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Técnicas de Cultura de Tecidos , Tirosina Transaminase/metabolismo
18.
Environ Toxicol ; 29(6): 665-71, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22778074

RESUMO

The present study investigated the effect of diphenyl diselenide [(PhSe)2 ] on metabolic disorders induced by acephate acute exposure in rats. We also investigated a possible mechanism of action of (PhSe)2 against hyperglycemia induced by acephate. (PhSe)2 was administered to rats at a dose of 10 or 30 mg/kg by oral gavage (p.o.) 1 hour prior to acephate administration (140 mg/kg; p.o.). Glucose and corticosterone levels as well as the lipid status were determined in plasma of rats. Cardiovascular risk factors and the atherogenic index were calculated. Glycogen levels as well as tyrosine aminotransferase (TAT) and glucose-6-phosphatase (G6Pase) activities were determined in livers of rats. Cerebral acetylcholinesterase (AChE) activity was assayed. Acephate induced an increase in glucose and corticosterone levels as well as in TAT and G6Pase activities. AChE activity was inhibited by acephate. Triglyceride (TG) levels and the cardiovascular risk factor TG/high-density lipoprotein-cholesterol (HDL) were increased by acephate. (PhSe)2 was effective against the metabolic disorders induced by acephate acute exposure in rats.


Assuntos
Derivados de Benzeno/farmacologia , Doenças Metabólicas/tratamento farmacológico , Compostos Organosselênicos/farmacologia , Compostos Organotiofosforados/toxicidade , Fosforamidas/toxicidade , Substâncias Protetoras/farmacologia , Acetilcolinesterase/metabolismo , Animais , Glicemia , HDL-Colesterol/sangue , Corticosterona/sangue , Glucose-6-Fosfatase/metabolismo , Glicogênio/metabolismo , Hiperglicemia/induzido quimicamente , Hiperglicemia/tratamento farmacológico , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Doenças Metabólicas/induzido quimicamente , Ratos , Ratos Wistar , Triglicerídeos/sangue , Tirosina Transaminase/metabolismo
19.
J Biosci Bioeng ; 117(5): 645-51, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24220646

RESUMO

Rosmarinic acid and salvianolic acid B are two important phenolic compounds with therapeutic properties in Salvia miltiorrhiza Bunge. The biosynthesis of rosmarinic acid is initiated by two parallel pathways, namely the phenylpropanoid pathway and the tyrosine-derived pathway. Salvianolic acid B is a structural dimer of rosmarinic acid and is believed to be derived from rosmarinic acid. In the current study, methyl jasmonate (MeJA) and hyphal extracts from fungi were used as elicitors to examine the relationship between enzymes in the two parallel pathways and accumulation of phenolic compounds in S. miltiorrhiza hairy root cultures. The results showed that accumulations of rosmarinic acid, salvianolic acid B and total phenolics were enhanced by MeJA while suppressed by fugal extracts. Responses of enzymes in the tyrosine-derived pathway, at both the gene transcript and enzyme activity levels, showed a better consistency with alterations of phenolic compounds content after the two elicitors treated. Our study implied that compared with enzymes in the phenylpropanoid pathway, enzymes in the tyrosine-derived pathway are more correlated to rosmarinic acid and salvianolic acid B biosynthesis in S. miltiorrhiza hairy roots.


Assuntos
Acetatos/farmacologia , Vias Biossintéticas , Cinamatos/metabolismo , Ciclopentanos/farmacologia , Depsídeos/metabolismo , Oxilipinas/farmacologia , Salvia miltiorrhiza/efeitos dos fármacos , Salvia miltiorrhiza/enzimologia , Benzofuranos/química , Benzofuranos/metabolismo , Biomassa , Vias Biossintéticas/efeitos dos fármacos , Vias Biossintéticas/genética , Cinamatos/química , Depsídeos/química , Regulação da Expressão Gênica de Plantas , Hifas/química , Fenóis/química , Fenóis/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Salvia miltiorrhiza/genética , Salvia miltiorrhiza/metabolismo , Fatores de Tempo , Transcinamato 4-Mono-Oxigenase/metabolismo , Tirosina/metabolismo , Tirosina Transaminase/metabolismo
20.
Nat Prod Commun ; 9(9): 1311-4, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25918800

RESUMO

Rosmarinic acid (a-O-caffeoyl-3,4-dihydroxyphenylacetic acid, RA) is a caffeoyl ester widely distributed in plants. cDNA clones encoding tyrosine aminotransferase (TAT1 and 2) and hydroxyphenylpyruvate reductase (HPPR) have been isolated from Scutellaria baicalensis. The open reading frames (ORFs) of SbTAT1 and 2 were 1230 and 1272 bp long and encoded 409 and 423 amino acid residues, respectively. HPPR corresponded to a 942-bp ORF and 313 amino acid residues of translated protein. To study the molecular mechanisms of TAT and HPPR and investigate RA accumulation in S. baicalensis, we examined the transcript levels of TAT isoforms and HPPR with quantitative real-time PCR and analyzed the RA content in different organs by using high-performance liquid chromatography. The transcript levels of SbTATI SbTAT2, and SbHPPR in the flowers were higher than those in other organs. RA was also highly accumulated in the flowers and with a trace amount in the roots. No RA was detected in the leaves and stems of S. baicalensis. The amount of accumulated RA in the flowers was 28.7 times higher than that in the roots. Our results will be helpful in elucidating the mechanisms of RA biosynthesis in S. baicalensis.


Assuntos
Cinamatos/metabolismo , Clonagem Molecular , Depsídeos/metabolismo , Oxirredutases/genética , Proteínas de Plantas/genética , Scutellaria baicalensis/enzimologia , Tirosina Transaminase/genética , Vias Biossintéticas , Oxirredutases/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Scutellaria baicalensis/genética , Tirosina Transaminase/metabolismo
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