Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Pharmaceuticals (Basel) ; 14(7)2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34358080

RESUMO

MT921 is a new injectable drug developed by Medytox Inc. to reduce submental fat. Cholic acid is the active pharmaceutical ingredient, a primary bile acid biosynthesized from cholesterol, endogenously produced by liver in humans and other mammals. Although individuals treated with MT921 could be administered with multiple medications, such as those for hypertension, diabetes, and hyperlipidemia, the pharmacokinetic drug-drug interaction (DDI) has not been investigated yet. Therefore, we studied in vitro against drug-metabolizing enzymes and transporters. Moreover, we predicted the potential DDI between MT921 and drugs for chronic diseases using physiologically-based pharmacokinetic (PBPK) modeling and simulation. The magnitude of DDI was found to be negligible in in vitro inhibition and induction of cytochrome P450s and UDP-glucuronosyltransferases. Organic anion transporting polypeptide (OATP)1B3, organic anion transporter (OAT)3, Na+-taurocholate cotransporting polypeptide (NTCP), and apical sodium-dependent bile acid transporter (ASBT) are mainly involved in MT921 transport. Based on the result of in vitro experiments, the PBPK model of MT921 was developed and evaluated by clinical data. Furthermore, the PBPK model of amlodipine was developed and evaluated. PBPK DDI simulation results indicated that the pharmacokinetics of MT921 was not affected by the perpetrator drugs. In conclusion, MT921 could be administered without a DDI risk based on in vitro study and related in silico simulation. Further clinical studies are needed to validate this finding.

3.
PLoS One ; 16(8): e0256869, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34449810

RESUMO

Human serum albumin (HSA) has been widely used as a pharmaceutical excipient in Botulinum toxin serotype A (BoNT/A) products that are indicated for use in therapeutics and cosmetics. However, HSA as a human-derived material has some concerns, such as the potential risk of transmission of infectious agents, an insufficient supply, and difficulty in maintaining a certain quality. For those reasons, newly developed BoNT/A products (CORETOX®, Medytox, Inc., Republic of Korea) contained polysorbate 20, a non-human-derived excipient, to replace the HSA. However, most safety studies of polysorbate 20 have been conducted with non-invasive routes of administration, and thus there are a few studies on the safety of polysorbate 20 when administered intramuscularly. To secure the in vivo safety profile of polysorbate 20, a four-week repeated intramuscular dose toxicity study (0.02, 0.1, and 0.4 mg/kg, one injection every two weeks for a total of three injections) was conducted in 66 Sprague-Dawley (SD) rats. An intradermal irritation study was further conducted with 18 New Zealand White (NZW) rabbits. The toxicological evaluation of HSA (0.06 and 0.12 mg/kg) was also carried out as a comparative substance. Systemic and local toxicities were not observed in any of the SD rats or NZW rabbits based on clinical signs, body weight, hematology, clinical biochemistry, macroscopic findings on necropsy, histopathology of the injection site, and allergic reactions. The current study suggested that intramuscular administration of polysorbate 20 was considered to be safe at a level similar to that of HSA, which has an in vivo safety profile accumulated over the years. This provided the basis for the in vivo safety profile of polysorbate 20 administered intramuscularly and the scientific reliability of the use of polysorbate 20 as an alternative to HSA, which is used as an excipient for various pharmaceuticals in terms of its safety.


Assuntos
Botulismo/tratamento farmacológico , Polissorbatos/farmacologia , Animais , Toxinas Botulínicas/antagonistas & inibidores , Excipientes , Humanos , Polissorbatos/efeitos adversos , Coelhos , Ratos , Ratos Sprague-Dawley , República da Coreia , Albumina Sérica Humana/efeitos adversos , Albumina Sérica Humana/uso terapêutico
4.
Clin Cosmet Investig Dermatol ; 14: 765-778, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34239313

RESUMO

PURPOSE: Hyaluronic acid (HA)-based dermal fillers have been approved for various clinical indications, both cosmetic and medical. Previous studies that have assessed the performance of HA dermal fillers have primarily focused on evaluating filler durability, and only a few have studied their distribution within the tissues. The present study aimed to compare tissue integration of various types of HA dermal fillers having different clinical indications and varying injection depths. METHODS: To examine the local inflammatory response and distribution pattern of 14 HA dermal fillers (six Neuramis [NEU], one Belotero [BEL], three Juvéderm [JUV], and four Restylane [RES]), each product was injected intradermally and subcutaneously at the backs of two male miniature pigs. Histopathological evaluation and visual examination of the tissue sections were conducted 1 and 4 weeks after injection. RESULTS: Mean inflammatory cell infiltration scores tended to be lower in response to fillers from the NEU and BEL series than to those from the JUV and RES series after intradermal and subcutaneous injection. Furthermore, the inflammatory response to fillers with higher physicochemical properties specifically designed for injection into deeper layers of the skin tended to be slightly higher than those designated for injection into more superficial layers. There was no significant difference in tissue integration according to clinical indication and injection depth, although fillers from the NEU and BEL series exhibited better tissue integration than those from the JUV and RES series. CONCLUSION: Our findings not only suggest that the local inflammatory response and tissue integration differ across HA dermal filler products, but also that these parameters could vary according to the recommended clinical indication and injection depth of the products.

5.
Clin Cosmet Investig Dermatol ; 14: 241-248, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33727845

RESUMO

PURPOSE: Hyaluronic acid (HA) is the most common injectable dermal filler used for soft-tissue augmentation, and can be removed non-surgically by directly injecting hyaluronidase. In this study, the hyaluronidase-mediated degradation of different types of HA fillers implanted subcutaneously at the back of hairless mice having filler residence time of four days or three months were compared. METHODS: Two sites at the back of female hairless mice were subcutaneously implanted with 0.1-mL of one of the seven HA fillers (NLL, NL, NDL, NVL, and ND, JUVX+, and RESLYFT) and injected with 30 IU or 60 IU hyaluronidase per 0.1-mL filler after reaching a filler residence time of 4 or 91 days, respectively. Filler bolus projection was measured using three-dimensional optical imaging over a 72 h period, and the implantation sites were histologically examined 2 weeks after hyaluronidase injection. RESULTS: Following hyaluronidase injection, all seven HA fillers showed a rapid decrease of filler volume within 24 h, and complete degradation was confirmed by histological examination after 2 weeks. There was no significant difference in filler volume reduction rate among the seven HA fillers, and no evidence of macroscopic or microscopic adverse effects were observed at the implantation sites. CONCLUSION: All seven HA fillers show comparable susceptibility to hyaluronidase-mediated degradation. HA fillers with prolonged filler residence time may require a higher dose of hyaluronidase to achieve efficient degradation owing to tissue integration.

6.
Pharmaceutics ; 13(2)2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33494145

RESUMO

Dermal fillers are gel-type substances for nonsurgical medical-device use to achieve facial rejuvenation. Currently, the most widely used skin fillers are hyaluronic-acid-based dermal fillers. This study aimed to explain the change in the volume of injected dermal fillers by developing a mathematical kinetic model for various dermal fillers. The kinetics of the injected fillers were separated by a biphasic phenomenon. We attributed an increase in filler volume to the hydration of hyaluronic acid molecules and injection-site reaction and a decrease in volume to enzyme-mediated degradation. To explain these in vivo characteristics of dermal fillers, we proposed a two-compartment model, divided into a depot compartment (where the filler was injected) and a subcutaneous compartment (an observation compartment where the fillers swell and degrade), assuming that the swelling and degradation occurred in accordance with the swelling and degradation rate constants, respectively. The model was developed using five hyaluronic-acid-based dermal fillers and NONMEM. We determined that the rate-limiting step for the complete degradation of the dermal fillers in vivo was the swelling phase, as described by the swelling rate constant (Kswell). This study could enable scientists developing novel dermal fillers to predict the in vivo behavior of fillers.

7.
Dermatol Surg ; 46(12): e132-e138, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32251006

RESUMO

BACKGROUND: A new complexing protein-free botulinum toxin Type A (CBoNT) with the same mechanism of action as the botulinum toxin complex onabotulinumtoxinA (OBoNT) and complexing protein-free incobotulinumtoxinA (IBoNT) was recently developed. OBJECTIVE: To compare the local paresis and chemodenervation efficacy of 3 different botulinum toxin Type A preparations in mice. MATERIALS AND METHODS: Efficacy and duration of action of CBoNT, OBoNT, and IBoNT after a single intramuscular injection to the right gastrocnemius was evaluated by digit abduction score (DAS) and compound muscle action potential (CMAP) assays. RESULTS: Mouse DAS and CMAP responses were comparable between CBoNT and OBoNT, indicating similar paresis and chemodenervation efficacy, as well as duration of action. Both botulinum toxins showed significantly higher efficacy and longer duration of action than IBoNT. Similarly, mean DAS potency of CBoNT (ED50: 3.85 ± 0.34 U/kg) and OBoNT (ED50: 4.13 ± 0.07 U/kg) were significantly higher compared with IBoNT (ED50: 6.70 ± 0.83 U/kg). CONCLUSION: CBoNT displays the same efficacy as OBoNT as shown by their comparable chemodenervation and local paretic effects, and demonstrates superior efficacy and duration of action compared with IBoNT. Likewise, CBoNT has comparable DAS potency to OBoNT and is superior to IBoNT.


Assuntos
Toxinas Botulínicas Tipo A/farmacologia , Músculo Esquelético/efeitos dos fármacos , Bloqueio Nervoso/métodos , Animais , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Feminino , Injeções Intramusculares , Camundongos , Modelos Animais , Músculo Esquelético/inervação , Fatores de Tempo
8.
Anal Chem ; 86(5): 2279-84, 2014 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-24506443

RESUMO

The sensitive detection of highly toxic botulinum neurotoxin (BoNT) from Clostridium botulinum is of critical importance because it causes human illnesses if foodborne or introduced in wounds and as an iatrogenic substance. Moreover, it has been recently considered a possible biological warfare agent. Over the past decade, significant progress has been made in BoNT detection technologies, including mouse lethality assays, enzyme-linked immunosorbent assays, and endopeptidase assays and by mass spectrometry. Critical assay requirements, including rapid assay, active toxin detection, sensitive and accurate detection, still remain challenging. Here, we present a novel method to detect active BoNTs using a Glyco-quantitative polymerase chain-reaction (qPCR) approach. Sialyllactose, which interacts with the binding-domain of BoNTs, is incorporated into a sialyllactose-DNA conjugate as a binding-probe for active BoNT and recovered through BoNT-immunoprecipitation. Glyco-qPCR analysis of the bound sialyllactose-DNA is then used to detect low attomolar concentrations of BoNT and attomolar to femtomolar concentrations of BoNT in honey, the most common foodborne source of infant botulism.


Assuntos
Toxinas Botulínicas/análise , Neurotoxinas/análise , Reação em Cadeia da Polimerase/métodos , Limite de Detecção , Espectrometria de Massas
9.
Dermatol Surg ; 39(1 Pt 2): 150-4, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23301818

RESUMO

BACKGROUND: Because more botulinum toxin (BoNT) preparations have become available worldwide, there is a clinical need to compare the pharmacologic profiles of these products. OBJECTIVE: We compared three different preparations: onabotulinumtoxinA (ona-BoNT/A), abobotulinumtoxinA (abo-BoNT/A), and Neuronox (neu-BoNT/A), in a mouse model using a digit abduction scoring (DAS) assay. METHODS: The efficacy, duration of effect, and safety margin of each preparation was determined after delivering a single injection to the right gastrocnemius (0-240 U/kg body weight of neu-BoNT/A or ona-BoNT/A; 0-600 Speywood Units/kg body weight of abo-BoNT/A). RESULTS: Neu-BoNT/A (intramuscular (IM) median effective dose (ED(50) ) 11.2 ± 2.7 U/kg) and ona-BoNT/A (IM ED(50) 11.9 ± 2.4 U/kg) had similar effects in terms of muscle weakness at significantly lower doses than abo-BoNT/A (IM ED(50) 41.2 ± 2.4 U/kg; p < .001). The safety margin (ratio between IM ED(50) and IM median lethal dose (LD(50) )) of neu-BoNT/A (10.7 ± 2.6 U/kg) was also similar to that of ona-BoNT/A (10.3 ± 1.3 U/kg) but significantly higher than that of abo-BoNT/A (5.9 ± 0.4 U/kg; p < .02). Neu-BoNT/A and ona-BoNT/A also produced comparable patterns of DAS response and body weight recovery by day 29. CONCLUSION: Neu-BoNT/A and ona-BoNT/A may be interchangeable based on a simple dose ratio.


Assuntos
Toxinas Botulínicas Tipo A/farmacologia , Neurotoxinas/farmacologia , Análise de Variância , Animais , Relação Dose-Resposta a Droga , Feminino , Dose Letal Mediana , Camundongos , Camundongos Endogâmicos ICR , Debilidade Muscular/induzido quimicamente , Músculo Esquelético/efeitos dos fármacos
11.
Toxicon ; 60(3): 341-7, 2012 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22613167

RESUMO

PURPOSE: We performed a prevalidation of the compound muscle action potential (CMAP) assay to determine the potency of botulinum neurotoxin type A (BoNT/A) with the aim of substituting for the mouse lethality test (LD50), which is used for quality control. METHODS: Prevalidation experiments were performed to demonstrate the specificity, linearity, accuracy, precision, range, limit of quantitation (LOQ), and robustness of the assay. For specificity, toxin detection ability was determined in the presence of neutralizing antibodies (0.8 and 8 IU/mL). Linearity of this assay was determined by measuring CMAP amplitude using nine concentrations (n = 3) in the range of 1-100 U/mL (n = 3). Accuracy was assessed using five concentrations (n = 3) in the range of 4-40 U/mL. Intermediate precision was confirmed by analyzing individually prepared reagents on multiple days by one operator (n = 3). Different body weights (23-25 and 25-27 g) and measurement times (3-5 and 5-7 min) after anesthetic induction were tested to assess robustness. RESULTS: This assay might have BoNT/A specificity, based on the CMAP amplitude recovery using a concentration of neutralizing antibodies. The calibration curves were linear over the range of 2-40 U/mL (R² = 0.982). The accuracy of 14 determinations was within the range of 89.8-118.6% compared to the theoretical values among 15 determinations, except one (131.3%). Assay variability was acceptable with coefficients of variation of 4.3-14.4%. The range of quantification and the LOQ were 4-40 U/mL and 4 U/mL, respectively. Different body weights and measurement times after inducing anesthesia had no effect on CMAP amplitude. CONCLUSIONS: These results suggest that the mouse CMAP assay is an alternative method to the standard LD50 potency test and meets the requirement of the three Rs (particularly refinement and reduction).


Assuntos
Potenciais de Ação/efeitos dos fármacos , Alternativas ao Uso de Animais , Toxinas Botulínicas Tipo A/farmacologia , Química Farmacêutica/métodos , Músculo Esquelético/efeitos dos fármacos , Bloqueadores Neuromusculares/farmacologia , Animais , Anticorpos Neutralizantes/metabolismo , Blefarospasmo , Antitoxina Botulínica/farmacologia , Toxinas Botulínicas Tipo A/antagonistas & inibidores , Calibragem , Estudos de Viabilidade , Feminino , Camundongos , Camundongos Endogâmicos ICR , Músculo Esquelético/metabolismo , Bloqueadores Neuromusculares/antagonistas & inibidores , Concentração Osmolar , Músculos Psoas/efeitos dos fármacos , Músculos Psoas/metabolismo , Controle de Qualidade , Reprodutibilidade dos Testes , Fatores de Tempo
12.
J Microbiol ; 45(6): 528-33, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18176536

RESUMO

In a previous study we generated an anti-Hepatitis B Virus (HBV) preS1 humanized antibody (HzKR127) that showed in vivo HBV-neutralizing activity in chimpanzees. However, the antigen-binding affinity of the humanized antibody may not be sufficient for clinical use and thus affinity maturation is required for better therapeutic efficacy. In this study, phage display technique was employed to increase the affinity of HzKR127. All six amino acid residues (Glu95-Tyr96-Asp97-Glu98-Ala99-Tyr100) in the heavy (H) chain complementarydetermining region 3 (HCDR3) of HzKR127 were randomized and phage-displayed single chain Fv (scFv) library was constructed. After three rounds of panning, 12 different clones exhibiting higher antigen-binding activity than the wild type ScFv were selected and their antigen-binding specificity for the preS1 confirmed. Subsequently, five ScFv clones were converted to whole IgG and subjected to affinity determination. The results showed that two clones (B3 and A19) exhibited an approximately 6 fold higher affinities than that of HzKR127. The affinity-matured humanized antibodies may be useful in anti-HBV immunotherapy.


Assuntos
Afinidade de Anticorpos/imunologia , Anticorpos Anti-Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Biblioteca de Peptídeos , Precursores de Proteínas/imunologia , Sequência de Aminoácidos , Especificidade de Anticorpos , Sequência de Bases , Western Blotting , Ensaio de Imunoadsorção Enzimática , Vetores Genéticos/genética , Antígenos de Superfície da Hepatite B/genética , Humanos , Dados de Sequência Molecular , Precursores de Proteínas/genética
13.
Toxicon ; 44(1): 19-25, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15225558

RESUMO

Botulinum neurotoxins (BoNTs), the causative agents for life-threatening human disease botulism, have been recognized as biological warfare agents. In this study, a neutralizing mouse monoclonal antibody against botulinum neurotoxin serotype B (BoNT/B), named BTBH-N1, was developed from mice immunized with BoNT/B toxoid without non-toxic components, which are generally associated with the toxin. Western blot analysis, using recombinant toxin fragments containing light (L), N-terminal half of heavy (HN) and C-terminal half of heavy chains, indicated that BTBH-N1 recognizes linear epitopes located on the HN domain. An in vivo neutralization assay with mice, was conducted to characterize the neutralization capacity of the BTBH-N1. Only 10 microg of BTBH-N1 completely neutralized 20 units (1 unit = one 50% lethal dose) of BoNT/B. Even though the Mab (up to 100 microg) failed to protect mice challenged with 100 units, it significantly prolonged the time to death in a dose dependent manner. BTBH-N1, the first neutralizing antibody against BoNT/B, could be further developed as effective biological therapeutics for preventing and treating botulism, as well as other diseases caused by BoNT/B.


Assuntos
Anticorpos Monoclonais/isolamento & purificação , Toxinas Botulínicas/metabolismo , Botulismo/prevenção & controle , Clostridium botulinum/química , Imunização , Animais , Anticorpos Monoclonais/metabolismo , Western Blotting , Toxinas Botulínicas Tipo A , Botulismo/imunologia , Reações Cruzadas/imunologia , Modelos Animais de Doenças , Eletroforese em Gel de Poliacrilamida , Epitopos/metabolismo , Camundongos , Testes de Neutralização , Fatores de Tempo
14.
Toxicology ; 186(1-2): 51-65, 2003 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-12604170

RESUMO

The trichothecenes are a group of mycotoxins that target leukocytes and have a wide range of immunomodulatory effects. Differential display analysis was applied to assess the effects of the trichothecenes deoxynivalenol (vomitoxin, DON) and satratoxin G (SG), on mRNA in the RAW 264.7 macrophage cell line. Cells were incubated with DON (1 microg/ml) or SG (5 ng/ml) for 2 h and total RNA then subjected to RT-PCR with a set of oligo(dT) primers. Resultant cDNA was amplified using an oligo (dT) downstream primer and an arbitrary decanucleotide upstream primer to make 35S-labeled PCR products. After separation of the products in denaturing polyacrylamide gel, 23 differentially expressed cDNA fragments were isolated and sequenced. Two of these were identified as known genes, namely, macrophage inflammatory protein-2 (MIP-2), a potent neutrophil chemoattractant involved in tissue injury and inflammation, and complement 3a receptor (C3aR), a proinflammatory mediator. Both MIP-2 and C3aR mRNAs were up-regulated by DON while only MIP-2 mRNA was induced by SG. Using commercially available antibodies, MIP-2 protein was also found to be induced by both DON and SG in RAW 264.7 cell cultures. When mice were treated with DON (12.5 mg/kg), splenic MIP-2 mRNA and serum MIP-2 levels were increased. MIP-2 mRNA and serum MIP-2 levels were synergistically increased when mice were co-treated with DON and LPS. Up-regulation of MIP-2 and C3aR are consistent with previous reports of trichothecene-induced inflammatory gene up-regulation and suggest that the specific genes affected may depend on trichothecene structures.


Assuntos
Antígeno de Macrófago 1/biossíntese , Macrófagos/efeitos dos fármacos , Monocinas/biossíntese , Tricotecenos/farmacologia , Animais , Quimiocina CXCL2 , Cruzamentos Genéticos , Perfilação da Expressão Gênica , Antígeno de Macrófago 1/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Monocinas/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tricotecenos/imunologia , Tricotecenos/metabolismo , Regulação para Cima/efeitos dos fármacos
15.
J Virol ; 77(4): 2784-8, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12552023

RESUMO

The proper folding and assembly of viral envelope proteins are mediated by host chaperones. In this study, we demonstrated that an endoplasmic reticulum luminal chaperone GRP78/BiP bound specifically to the pre-S1 domain of the L protein in vitro and in vivo where complete viral particles were secreted, suggesting that GRP78/BiP plays an essential role in the proper folding of the L protein and/or assembly of viral envelope proteins.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Choque Térmico , Vírus da Hepatite B/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas do Envelope Viral/metabolismo , Sequência de Aminoácidos , Animais , Células COS , Retículo Endoplasmático/metabolismo , Chaperona BiP do Retículo Endoplasmático , Vírus da Hepatite B/genética , Vírus da Hepatite B/patogenicidade , Humanos , Dados de Sequência Molecular , Coelhos , Células Tumorais Cultivadas
16.
Toxicology ; 172(3): 169-79, 2002 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-11893416

RESUMO

Interleukin-2 (IL-2) gene expression is superinduced by the trichothecene mycotoxin vomitoxin (VT, deoxynivalenol) in primary and cloned murine T cells-an activity that relates to this toxin's capacity to inhibit protein synthesis. Binding of the transcription factor ZEB (NIL-2-a) to the negative regulatory element NRE-A plays a critical role in silencing IL-2 expression in the EL-4 cell line, a murine Th1-like lymphoma. The objective of this study was to test the hypothesis that VT impairs NRE-A-binding activity in the EL-4 T cells model. Electrophoretic mobility shift assay (EMSA) in control EL-4 cells revealed a slower migrating band, previously identified as ZEB, and a faster migrating band. VT inhibited NRE-A binding activity in unstimulated EL-4 cells as evidenced by the concentration-dependent reduction of both bands with as little as 50 ng/ml of the toxin being inhibitory. Specificity of NRE-A binding for the two bands was verified by demonstrating (1) competition with excess unlabeled NRE-A probe and absence of competition with mutant NRE-A or unrelated (NF-kappaB) probes and (2) EMSA supershift using antibody specific for ZEB. NRE-A binding activity was also reduced when cells were treated with phorbol 12-myristate 13-acetate (PMA) plus ionomycin (ION). Cotreatment of VT potentiated PMA+ION-mediated reduction of the NRE-A binding activity in concentration-dependent fashion. VT-mediated reduction of NRE-A binding was observed in PMA+ION-stimulated cells as early as 2 h and was still detectable after 24 h. Competitive RT-PCR analysis of mRNA indicated that VT did not reduce ZEB transcript levels. Western analysis of nuclear extracts revealed that, although VT exposure decreased ZEB protein expression, the effects were minimal, required high VT concentrations (500-1000 ng/ml) and were not qualitatively consistent with large concomitant decreases in NRE-A binding activity. Furthermore, VT at levels up to 1000 ng/ml had no effect on ZEB expression in whole cell lysates, suggesting that VT did not selectively inhibit translation of this negative transcription factor. Taken together, these data indicate that the capacity of VT to up-regulate IL-2 expression may relate, in part, to its capacity to decrease ZEB binding to the negative regulatory element within this cytokine's promoter. The inability to associate decreased NRE-A binding with impaired ZEB transcription or translation suggests that post-translational modification of this negative transcription factor may be requisite for VT's down-regulatory effects.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Interleucina-2/biossíntese , Micotoxinas/farmacologia , Proteínas Nucleares/metabolismo , Fatores de Transcrição , Tricotecenos/farmacologia , Animais , Western Blotting , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Células Cultivadas , Eletroforese , Genes Reguladores/genética , Proteínas de Homeodomínio/genética , Interleucina-2/genética , Camundongos , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/genética , Proteínas Repressoras/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...