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1.
Toxins (Basel) ; 15(9)2023 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-37755959

RESUMO

Kashin-Beck disease (KBD) is a multifactorial endemic disease that only occurs in specific Asian areas. Mycotoxin contamination, especially from the Fusarium spp., has been considered as one of the environmental risk factors that could provoke chondrocyte and cartilage damage. This study aimed to investigate whether new mycotoxins could be identified in KBD-endemic regions as a potential KBD risk factor. This was investigated on 292 barley samples collected in Tibet during 2009-2016 and 19 wheat samples collected in Inner Mongolia in 2006, as control, from KBD-endemic and non-endemic areas. The LC-HRMS(/MS) data, obtained by a general mycotoxin extraction technic, were interpreted by both untargeted metabolomics and molecular networks, allowing us to identify a discriminating compound, enniatin B, a mycotoxin produced by some Fusarium spp. The presence of Fusarium spp. DNA was detected in KBD-endemic area barley samples. Further studies are required to investigate the role of this mycotoxin in KBD development in vivo.


Assuntos
Fusarium , Hordeum , Doença de Kashin-Bek , Micotoxinas , Grão Comestível , Doença de Kashin-Bek/epidemiologia , China/epidemiologia
2.
Psychol Trauma ; 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37650802

RESUMO

OBJECTIVE: Though research on secondary traumatic stress (STS) has greatly increased in the past decade, to date the field lacks a coherent set of guiding principles for practice that behavioral health providers and organizations can use to mitigate the occurrence and impact of STS. As such it is important to identify effective strategies, grounded in research and professional experience, to reduce the occurrence and impact of STS among behavioral health professionals and organizations. METHOD: We conducted a four-stage modified Delphi survey. Thirty-one international STS experts were invited to participate, with a minimum of 19 responding in each round. Thematic analysis was conducted on qualitative data, which was incorporated into revisions of the principles. RESULTS: Consensus was achieved on 14 principles, seven targeted at individual professionals, and seven targeted at organizations. CONCLUSIONS: This is the first effort to delineate principles for practice intended to reduce the occurrence and impact of STS in individual and organizational practice in behavioral health services. The principles are intended to inform best practices for individuals and organizations providing services to persons and communities who have experienced trauma and thereby improve the quality and effectiveness of services to traumatized populations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

3.
Can Fam Physician ; 64(3): 204-211, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29540391

RESUMO

OBJECTIVE: To understand the primary care experiences of women who have a history of childhood trauma and chronic disease. DESIGN: Qualitative study using in-depth interviews with directed content analysis. SETTING: Family health team in Kingston, Ont. PARTICIPANTS: Twenty-six women. METHODS: Letters of invitation were sent to eligible participants followed by a telephone survey. Women with an adverse childhood experience (ACE) score of 4 or higher and with 2 or more chronic conditions were invited to participate in a one-on-one interview. MAIN FINDINGS: Participants were frequent users of health care services. Most had not been asked about ACEs by their family physicians. Most participants believed that their history of ACEs was important to their health and that providers should ask about childhood experiences. When participants discussed their primary care experiences, the following 6 common themes evolved: the importance of continuity of care; challenges with family medicine residents; provider awareness of abuse history; distress due to triggering events; characteristics of clinic staff and space; and engagement in care plans and choice. These discussions revealed that participants' primary care experiences were not always informed by the principles of trauma-informed care. CONCLUSION: Understanding the effect of ACEs on women's health is important. Incorporating a trauma-informed approach can be beneficial and enhance the experience of patients. Physicians should learn to ask patients about their childhood experiences, as it is important to their health care.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância/psicologia , Doença Crônica , Anamnese , Atenção Primária à Saúde , Feminino , Humanos , Entrevistas como Assunto , Relações Profissional-Paciente , Pesquisa Qualitativa
4.
Healthcare (Basel) ; 5(1)2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28257043

RESUMO

BACKGROUND AND OBJECTIVES: Several studies revealed clinical signs of stunting and rickets among rural populations of Tibet Autonomous Region (T.A.R.), and especially amid children. Further, these populations are affected by a bone disease named Kashin-Beck disease (KBD). However, little is known about the dietary status of this population. This survey aimed to assess the usual intakes of young Tibetan children living in rural areas around Lhasa for energy, water, and ten minerals and trace elements (Na, K, Ca, P, Mg, Fe, Zn, Cu, Mn, and Se) involved in bone metabolism. DESIGN: A cross-sectional survey was designed. Totally, 250 pre-school children aged 3-5 years living in rural areas were enrolled. The 24-h food recall method was used to collect the intakes for two days, during two different seasons (September 2012 and April 2013). Because Tibetan foods are mainly derived from local agriculture and artisanal production, a combination of food composition tables was compiled, including specific and local food composition data. RESULTS: The Chinese dietary recommended intakes are not met for most of the elements investigated. Intake of sodium is much too high, while usual intakes are too low for K, Ca, Zn, Cu, and Se. Bioavailability of Ca, Fe, and Zn may be of concern due to the high phytic acid content in the diet. CONCLUSION: These nutrient imbalances may impact growth and bone metabolism of young Tibetan children. The advantages of the implementation of food diversification programs are discussed as well as the relevance of supplements distribution.

5.
Trop Med Int Health ; 21(6): 768-75, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27102369

RESUMO

OBJECTIVE: To evaluate the effect of calcium (15 mmol/day) and vitamin D (625 µg/month), as single supplement or in combination, vs. no supplement on growth, clinical signs of rickets and Kashin-Beck disease (KBD) and dental health. METHODS: Prospective controlled trial involving children aged 0-5 years living in four groups of villages in a KBD-endemic rural area of central Tibet who received either calcium and/or vitamin D or no supplement. The cohort was followed over 3 years. Primary outcome was the impact of the different supplementation regimes on KBD, rickets and growth; secondary outcomes were impact on urinary levels of calcium and phosphorus, biomarkers of bone and cartilage turnover, and dental health. RESULTS: No difference was observed between the four groups with regard to anthropometric data, rickets, KBD, urinary levels of CrossLaps(®) and CartiLaps(®) . Weight for height or age, mid-upper arm circumference and skinfold thickness decreased in the four groups. Height for age increased and the prevalence of KBD fell in the four groups. Dental health was better in the group receiving calcium and vitamin D. Urinary calcium levels increased after 3 years of follow-up in all groups; the group receiving vitamin D had a higher increase (P-value: 0.044). The same global increase was observed for urinary phosphorus levels; the group receiving calcium had a higher increase (P-value: 0.01). CONCLUSIONS: Calcium and vitamin D failed to improve growth and bone metabolism of children living in a KBD-endemic rural area. Calcium and vitamin D supplementation improved dental health.


Assuntos
Estatura/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Cálcio da Dieta/farmacologia , Cálcio/farmacologia , Doença de Kashin-Bek , Raquitismo , Vitamina D/farmacologia , Osso e Ossos/metabolismo , Cálcio/urina , Cálcio da Dieta/urina , Pré-Escolar , Suplementos Nutricionais , Doenças Endêmicas , Feminino , Crescimento/efeitos dos fármacos , Humanos , Lactente , Recém-Nascido , Doença de Kashin-Bek/tratamento farmacológico , Doença de Kashin-Bek/epidemiologia , Masculino , Minerais/farmacologia , Minerais/urina , Fósforo/urina , Prevalência , Estudos Prospectivos , Raquitismo/tratamento farmacológico , Tibet/epidemiologia , Dente/efeitos dos fármacos , Vitaminas/farmacologia
7.
J Trace Elem Med Biol ; 32: 86-106, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26302917

RESUMO

The human skeleton, made of 206 bones, plays vital roles including supporting the body, protecting organs, enabling movement, and storing minerals. Bones are made of organic structures, intimately connected with an inorganic matrix produced by bone cells. Many elements are ubiquitous in our environment, and many impact bone metabolism. Most elements have antagonistic actions depending on concentration. Indeed, some elements are essential, others are deleterious, and many can be both. Several pathways mediate effects of element deficiencies or excesses on bone metabolism. This paper aims to identify all elements that impact bone health and explore the mechanisms by which they act. To date, this is the first time that the effects of thirty minerals on bone metabolism have been summarized.


Assuntos
Osso e Ossos/metabolismo , Oligoelementos/farmacologia , Osso e Ossos/efeitos dos fármacos , Humanos
9.
Eur J Pediatr ; 171(8): 1185-91, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22354482

RESUMO

UNLABELLED: In order to describe the growth of 0-5-year-old Tibetan children living in a Kashin-Beck disease (KBD) endemic rural area and to examine the relationship between anthropometric indicators and clinical signs of rickets, we analyzed the baseline data of a cohort of 668 children enrolled in a prospective program of calcium and vitamin D supplementation. Tibetan children suffer from growth retardation. Z score of weight-for-age, height-for-age, weight-for-height was below -2 in 32.5%, 27.7%, and 12.1% of the children, respectively. Clinical signs of severe rickets are highly prevalent. Underweight, stunting, and clinical rickets increases with age. Prevalence of malnutrition was higher in the presence of signs of rickets. The proportion of children with a head circumference Z score < -2 was lowest when signs of rickets were observed. CONCLUSION: Stunting and underweight are frequent and probably associated with rickets.


Assuntos
Doença de Kashin-Bek/etiologia , Desnutrição/complicações , Distribuição por Idade , Pré-Escolar , Doenças Endêmicas , Feminino , Gráficos de Crescimento , Transtornos do Crescimento/complicações , Transtornos do Crescimento/diagnóstico , Transtornos do Crescimento/epidemiologia , Humanos , Lactente , Recém-Nascido , Doença de Kashin-Bek/epidemiologia , Masculino , Desnutrição/diagnóstico , Desnutrição/epidemiologia , Prevalência , Estudos Prospectivos , Raquitismo/complicações , Raquitismo/diagnóstico , Raquitismo/epidemiologia , Magreza/complicações , Magreza/diagnóstico , Magreza/epidemiologia , Tibet/epidemiologia , Síndrome de Emaciação/complicações , Síndrome de Emaciação/diagnóstico , Síndrome de Emaciação/epidemiologia
10.
Anal Biochem ; 412(1): 96-101, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21272561

RESUMO

Alpha-class glutathione transferases (GSTs) found expressed in human tissues constitute a family of four homologous enzymes with contrasting enzyme activities. In particular, GST A3-3 has been shown to contribute to the biosynthesis of steroid hormones in human cells and is selectively expressed in steroidogenic tissues. The more ubiquitous GST A1-1, GST A2-2, and GST A4-4 appear to be primarily involved in detoxification processes and are expressed at higher levels than GST A3-3. We are interested in studying the cell and tissue expression of the GST A3-3 gene, yet the existence of highly expressed sequence-similar homologs and of several splice variants is a serious challenge for the specific detection of unique transcript species. We found that published polymerase chain reaction (PCR) primers for GST A3-3 lack the specificity required for reliable quantitative analysis. Therefore, we designed quantitative PCR (qPCR) primers with greatly increased discrimination power for the human GSTA3 full-length transcript. The improved primers allow accurate discrimination between GST A3-3 and the other alpha-class GSTs and so are of great value to studies of the expression of the GSTA3 gene. The novel primers were used to quantify GSTA3 transcripts in human embryonic liver and steroidogenic cell lines.


Assuntos
Glutationa Transferase/análise , Reação em Cadeia da Polimerase/métodos , Sequência de Bases , Linhagem Celular , Humanos , Fígado/enzimologia , Isoformas de Proteínas/análise , Alinhamento de Sequência
11.
Arch Biochem Biophys ; 507(2): 205-11, 2011 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21172301

RESUMO

An alpha-class glutathione transferase (GST) has been cloned from pig gonads. In addition to two conservative point mutations our nucleotide sequence presents a frame shift resulting from a missing A as compared to a previously published porcine GST A1-1 sequence. The deduced C-terminal amino-acid segment of the protein differs between the two variants. Repeated sequencing of cDNA isolated from different tissues and animals ruled out the possibility of a cloning artifact, and the deduced amino acid sequence of our clone showed higher similarity to related mammalian GST sequences. Hereafter, we refer to our cloned enzyme as GST A1-1 and to the previously published enzyme as GST A1-1(∗). The study of the tissue distribution of the GSTA1 mRNA revealed high expression levels in many organs, in particular adipose tissue, liver, and pituitary gland. Porcine GST A1-1 was expressed in Escherichia coli and its kinetic properties were determined using alternative substrates. The catalytic activity in steroid isomerization reactions was at least 10-fold lower than the corresponding values for porcine GST A2-2, whereas the activity with 1-chloro-2,4-dinitrobenzene was approximately 8-fold higher. Differences in the H-site residues of mammalian Alpha-class GSTs may explain the catalytic divergence.


Assuntos
Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Suínos , Sequência de Aminoácidos , Animais , Sequência de Bases , Biocatálise , Clonagem Molecular , DNA Complementar/genética , Feminino , Regulação da Expressão Gênica , Glutationa Transferase/química , Glutationa Transferase/isolamento & purificação , Humanos , Isoenzimas/química , Isoenzimas/isolamento & purificação , Cinética , Masculino , Dados de Sequência Molecular , Especificidade por Substrato
12.
Biochem J ; 431(1): 159-67, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20673231

RESUMO

A primary role of GSTs (glutathione transferases) is detoxication of electrophilic compounds. In addition to this protective function, hGST (human GST) A3-3, a member of the Alpha class of soluble GSTs, has prominent steroid double-bond isomerase activity. The isomerase reaction is an obligatory step in the biosynthesis of steroid hormones, indicating a special role of hGST A3-3 in steroidogenic tissues. An analogous GST with high steroid isomerase activity has so far not been found in any other biological species. In the present study, we characterized a Sus scrofa (pig) enzyme, pGST A2-2, displaying high steroid isomerase activity. High levels of pGST A2-2 expression were found in ovary, testis and liver. In its functional properties, other than steroid isomerization, pGST A2-2 was most similar to hGST A3-3. The properties of the novel porcine enzyme lend support to the notion that particular GSTs play an important role in steroidogenesis.


Assuntos
Glutationa Transferase/química , Isoenzimas/química , Esteroide Isomerases/química , Sequência de Aminoácidos , Animais , Catálise , Feminino , Glutationa Transferase/metabolismo , Humanos , Isoenzimas/metabolismo , Cinética , Masculino , Dados de Sequência Molecular , Ovário/metabolismo , Alinhamento de Sequência , Esteroide Isomerases/metabolismo , Suínos , Testículo/metabolismo
13.
Biochem J ; 414(1): 103-9, 2008 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-18426392

RESUMO

hGSTA3-3 (human Alpha-class glutathione transferase 3-3) efficiently catalyses steroid Delta(5)-Delta(4) double-bond isomerization in vitro, using glutathione as a cofactor. This chemical transformation is an obligatory reaction in the biosynthesis of steroid hormones and follows the oxidation of 3beta-hydroxysteroids catalysed by 3beta-HSD (3beta-hydroxysteroid dehydrogenase). The isomerization has commonly been ascribed to a supplementary function of 3beta-HSD. The present study is the first to provide evidence that hGSTA3-3 contributes to this step in steroid hormone biosynthesis in complex cellular systems. First, we find glutathione-dependent Delta(5)-Delta(4) isomerase activity in whole-cell extracts prepared from human steroidogenic cells. Secondly, effective inhibitors of hGSTA3-3 dramatically decrease the conversion of Delta(5)-androstene-3,17-dione into Delta(4)-androstene-3,17-dione in cell lysates. Thirdly, we show that RNAi (RNA interference) targeting hGSTA3-3 expression decreases by 30% the forskolin-stimulated production of the steroid hormone progesterone in a human placental cell line. This effect is achieved at low concentrations of two small interfering RNAs directed against distinct regions of hGSTA3-3 mRNA, and is weaker in unstimulated cells, in which hGSTA3-3 expression is low. The results concordantly show that hGSTA3-3 makes a significant contribution to the double-bond isomerization necessary for steroid hormone biosynthesis and thereby complements the indispensable 3beta-hydroxysteroid oxidoreductase activity of 3beta-HSD. The results indicate that the lower isomerase activity of 3beta-HSD is insufficient for maximal rate of cellular sex hormone production and identify hGSTA3-3 as a possible target for pharmaceutical intervention in steroid hormone-dependent diseases.


Assuntos
Marcação de Genes , Glutationa Transferase/genética , Placenta/citologia , Placenta/enzimologia , Progesterona/biossíntese , Progesterona/genética , Linhagem Celular , Inibidores Enzimáticos/química , Feminino , Marcação de Genes/métodos , Glutationa Transferase/antagonistas & inibidores , Glutationa Transferase/fisiologia , Hormônios Esteroides Gonadais/biossíntese , Hormônios Esteroides Gonadais/genética , Hormônios Esteroides Gonadais/fisiologia , Humanos , Placenta/metabolismo , Interferência de RNA , Estereoisomerismo
14.
Mol Pharmacol ; 73(5): 1558-67, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18296503

RESUMO

We describe a novel cis-element in the 5' coding region of p53 mRNA and its interaction with heterogeneous nuclear ribonucleoprotein (hnRNP)C1/C2. This element is located in a putative hairpin loop structure, within the first 101 nucleotides downstream of the start codon. The binding of hnRNPC1/C2 is strongly enhanced in response to the DNA-damaging drug cisplatin [cis-diamminedichloroplatinum(II)] and the cytostatic transcriptional inhibitor actinomycin D (dactinomycin), both known inducers of apoptosis and p53. Strongly stimulated binding is observed in both nuclear and cytoplasmic compartments, and it is accompanied by a cytoplasmic increase of hnRNPC1/C2. Changes in hnRNPC1/C2 protein levels are not proportional to binding activity, suggesting qualitative changes in hnRNPC1/C2 upon activation. Phosphorylation studies reveal contrasting characteristics of the cytoplasmic and nuclear hnRNPC1/C2 interaction with p53 mRNA. Results from chimeric p53-luciferase reporter constructs suggest that hnRNPC1/C2 regulates p53 expression via this binding site. Our results are consistent with a mechanism in which the interaction of hnRNPC1/C2 with a cis-element within the coding region of the p53 transcript regulates the expression of p53 mRNA before and during apoptosis. In addition, we report that preapoptotic signals induced by transcriptional inhibition trigger the appearance of a truncated, exclusively cytoplasmic 43-kDa variant of p53 before apoptosis.


Assuntos
Citostáticos/farmacologia , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Sequências Reguladoras de Ácido Ribonucleico/genética , Proteína Supressora de Tumor p53/genética , Sequência de Aminoácidos , Sequência de Bases , Sítios de Ligação , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Cisplatino/farmacologia , Códon/genética , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Dactinomicina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Humanos , Luciferases/metabolismo , Dados de Sequência Molecular , Peso Molecular , Mutação/genética , Conformação de Ácido Nucleico/efeitos dos fármacos , Fases de Leitura Aberta , Especificidade de Órgãos/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Sondas RNA/química , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcrição Gênica/efeitos dos fármacos , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/metabolismo
15.
Fetal Diagn Ther ; 24(4): 503-5, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19145084

RESUMO

OBJECTIVE: It was the aim of this study to report a case of fetomaternal hemorrhage (FMH) that was successfully treated with fetal intravascular transfusions in which the middle cerebral artery peak systolic velocity (MCA-PSV) detected fetal anemia. METHODS: A massive FMH occurred twice in a healthy 33-year-old pregnant woman at 26 and 29 weeks of gestation with no evident cause. Four repeated intravascular transfusions were performed. The MCA-PSV increased in the presence of anemia and decreased following correction of fetal hematocrit. RESULTS: A healthy neonate was delivered at 33 weeks of gestation. CONCLUSION: MCA-PSV detected fetal anemia both before the first transfusion and following the next intravascular transfusions. In our case, the change in fetal blood viscosity following transfusion with adult blood did not affect the MCA-PSV value for detection of fetal anemia.


Assuntos
Transfusão de Sangue Intrauterina , Transfusão Feto-Materna/terapia , Adulto , Anemia/terapia , Velocidade do Fluxo Sanguíneo , Feminino , Hematócrito , Humanos , Recém-Nascido , Artéria Cerebral Média/fisiologia , Gravidez , Segundo Trimestre da Gravidez , Índice de Gravidade de Doença
16.
Mol Immunol ; 44(12): 3204-10, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17379310

RESUMO

Glucocorticoids down regulate the inducible nitric oxide synthase (iNOS) gene both transcriptionally and post-transcriptionally. The post-transcriptional events are suggested to involve destabilization of the iNOS transcript although the molecular mechanisms for this effect are not known. Recently, our laboratory demonstrated a lipopolysaccharide (LPS)/interferon-gamma (IFNgamma)-induction-dependent interaction of heterogeneous nuclear ribonucleoprotein (hnRNP) I and hnRNPL with a destabilizing element contained in the 3'untranslated region (UTR) of iNOS mRNA. The aim of this study was to investigate if dexamethasone, which down regulates iNOS, is able to modulate this protein-mRNA interaction. As expected, dexamethasone inhibited the induction of iNOS by LPS and IFNgamma in RAW 264.7 cells, and destabilized the iNOS mRNA. Dexamethasone also counteracted the LPS/IFNgamma-induced disappearance of a gel shifted iNOS mRNA-protein complex containing hnRNPI and hnRNPL. UV cross-linking and Western blot analyses revealed that the RNA-binding and levels of hnRNPI, which decreased by LPS/IFNgamma treatment, were restored by dexamethasone. The results support our hypothesis that hnRNPI is pivotal in the post-transcriptional regulation of iNOS and strongly suggest that hnRNPI is one of the trans-acting factors mediating the post-transcriptional effects of dexamethasone.


Assuntos
Dexametasona/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Ribonucleoproteínas Nucleares Heterogêneas/fisiologia , Óxido Nítrico Sintase Tipo II/genética , Regiões 3' não Traduzidas/genética , Animais , Linhagem Celular , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Camundongos , Óxido Nítrico Sintase Tipo II/efeitos dos fármacos
17.
Biochim Biophys Acta ; 1770(1): 130-6, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16934407

RESUMO

Bovine glutathione transferase A1-1 (bGST A1-1) and human GST A3-3 (hGST A3-3) share both high amino acid sequence similarity and selective expression in steroidogenic organs. hGST A3-3 is the most efficient steroid isomerase known in mammals, and is thought to catalyze isomerization reactions in the biosynthesis of steroid hormones. We observed that four out of five residues essential to the high steroid isomerase activity of hGST A3-3 are conserved in bGST A1-1. The bovine GST was cloned, heterologously expressed, and purified to homogeneity. Its specific activity towards classical GST substrates and two steroids, Delta(5)-androstene-3,17-dione and Delta(5)-pregnene-3,20-dione, was studied, and the steady-state kinetic parameters with the steroids were determined. We find that bGST A1-1 exhibits enzymatic activities comparable to those of hGST A3-3 towards non-steroid substrates. However, the bovine enzyme had 100 times lower catalytic efficiency in steroid isomerization reactions than the human GST. Nevertheless, bGST A1-1 was found as efficient as bovine 3beta-hydroxysteroid dehydrogenase as a steroid isomerase. We discuss likely reasons for the contrasting steroid isomerase activities of bGST A1-1 and hGST A3-3, and alternative roles of bGST A1-1.


Assuntos
Glutationa Transferase/metabolismo , Isomerases/metabolismo , Sequência de Aminoácidos , Animais , Bovinos , DNA Complementar , Glutationa Transferase/genética , Humanos , Isomerases/genética , Cinética , Dados de Sequência Molecular , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
18.
Mol Immunol ; 44(4): 434-42, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16584775

RESUMO

The aim of this study was to investigate the role of heterogeneous nuclear ribonucleoprotein I (hnRNPI) and hnRNPL in the regulation of the murine inducible nitric oxide synthase (iNOS) gene during inflammation. Treatment of mice with lipopolysaccharide (LPS)/D-galactosamine, or of RAW 264.7 cells with LPS/interferon-gamma (IFN-gamma), strongly increased iNOS expression while reducing hnRNPI levels and complex formation between hnRNPI/hnRNPL and the 3'-untranslated region (3'-UTR) of iNOS mRNA. Introduction of the iNOS 3'-UTR to a luciferase reporter gene reduced its expression in RAW 264.7 cells. However, when hnRNPI and hnRNPL binding sites were deleted, luciferase expression was recovered. LPS/IFN-gamma increased the luciferase activity of the full-length 3'-UTR construct compared to control, while its effects on the deletion constructs were modest. The results indicate that LPS/IFN-gamma induce iNOS through a mechanism involving hnRNPI and hnRNPL binding to iNOS 3'-UTR. Our data suggest that iNOS mRNA degradation is promoted upon binding of hnRNPI and hnRNPL to a destabilizing region within its 3'-UTR, while inflammatory stimuli causing dissociation of the mRNA-protein complex, yield a more stable transcript. This appears to be particularly significant during extended inflammatory stimuli, resulting in sustained nitric oxide production. The critical event launching this process appears to be the degradation of hnRNPI.


Assuntos
Regulação Enzimológica da Expressão Gênica , Ribonucleoproteínas Nucleares Heterogêneas Grupo L/genética , Ribonucleoproteínas Nucleares Heterogêneas/genética , Óxido Nítrico Sintase Tipo II/genética , RNA Mensageiro/metabolismo , Regiões 3' não Traduzidas/genética , Regiões 3' não Traduzidas/metabolismo , Animais , Ribonucleoproteínas Nucleares Heterogêneas Grupo L/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Inflamação/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos DBA , Ligação Proteica , Processamento Pós-Transcricional do RNA , RNA Mensageiro/genética , Fator de Necrose Tumoral alfa/farmacologia
19.
Mol Pharmacol ; 67(4): 1325-33, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15657367

RESUMO

We have investigated the role of the aryl hydrocarbon receptor (AHR) in the regulation of the Cyp2a5 gene. The C57BL/6 and DBA/2 mouse strains with a genetically determined difference in AHR function were used to study the CYP2A5 induction by typical AHR ligands, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3-methylcholanthrene. The CYP2A5 mRNA up-regulation in these mouse strains showed a difference in response, typical for AHR-regulated genes, both by TCDD in cultured primary hepatocytes and by 3-methylcholanthrene in vivo. In primary hepatocytes, TCDD caused a 3-fold elevation of the CYP2A5 protein level and a similar induction of the CYP2A5-catalyzed coumarin 7-hydroxylation activity. In reporter gene assays, the Cyp2a5 promoter region -3033 to +10 mediated a 2- to 5-fold induction of luciferase activity by TCDD treatment in primary hepatocytes and in Hepa-1 hepatoma cells with an intact AHR/AHR nuclear translocator (ARNT) complex. In Hepa-1 variant cell lines with deficiencies in the AHR/ARNT complex, the absence of ARNT abolished the induction. A putative AHR response element (XRE) was identified in the Cyp2a5 promoter at the position -2514 to -2492 and found to interact with the AHR/ARNT heterodimer. Transfection experiments combined with mutation of the XRE site indicated that the site partly mediates the TCDD induction of Cyp2a5. An additional AHR-dependent mechanism also regulates the proximal promoter of the Cyp2a5 gene. In conclusion, our studies showed that AHR ligands up-regulate Cyp2a5 transcriptionally by an AHR/ARNT-dependent mechanism and established Cyp2a5 as a novel AHR-regulated gene.


Assuntos
Hidrocarboneto de Aril Hidroxilases/genética , Regulação Enzimológica da Expressão Gênica , Oxigenases de Função Mista/genética , Receptores de Hidrocarboneto Arílico/fisiologia , Animais , Hidrocarboneto de Aril Hidroxilases/análise , Hidrocarboneto de Aril Hidroxilases/biossíntese , Translocador Nuclear Receptor Aril Hidrocarboneto , Citocromo P-450 CYP2A6 , Família 2 do Citocromo P450 , Proteínas de Ligação a DNA/fisiologia , Indução Enzimática/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Oxigenases de Função Mista/análise , Oxigenases de Função Mista/biossíntese , Dibenzodioxinas Policloradas/farmacologia , RNA Mensageiro/análise , Fatores de Transcrição/fisiologia , Transcrição Gênica
20.
Methods Enzymol ; 401: 265-78, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16399392

RESUMO

Glutathione transferases (GSTs) constitute a superfamily of detoxifying enzymes with a major role in protecting cellular macromolecules from reactive electrophilic compounds. A growing body of evidence suggests, however, that at least certain glutathione transferases are involved in other essential cellular processes, such as cellular signaling and anabolic pathways. One of them is the human GST A3-3, which is selectively expressed in steroidogenic organs and which efficiently catalyzes the obligatory isomerization of the Delta(5)-ketosteroid precursors in the biosynthesis of progesterone and testosterone. In this chapter, we summarize the current knowledge on human GST A3-3 and describe methods for heterologous expression and functional characterization of the enzyme.


Assuntos
Glutationa Transferase/metabolismo , Isomerases/metabolismo , Esteroides/metabolismo , Processamento Alternativo , Sequência de Aminoácidos , Animais , Clonagem Molecular , Glutationa Transferase/química , Glutationa Transferase/genética , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , Isomerases/química , Isomerases/genética , Dados de Sequência Molecular , Estrutura Molecular , Esteroides/química , Distribuição Tecidual
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