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1.
J Vis Exp ; (167)2021 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-33522504

RESUMO

High demand for antibodies as therapeutic interventions for various infectious, metabolic, autoimmune, neoplastic, and other diseases creates a growing need in developing efficient methods for recombinant antibody production. As of 2019, there were more than 70 FDA-approved monoclonal antibodies, and there is exponential growth potential. Despite their promise, limiting factors for widespread use are manufacturing costs and complexity. Potentially, plants offer low-cost, safe, and easily scalable protein manufacturing strategies. Plants like Nicotiana benthamiana not only can correctly fold and assemble complex mammalian proteins but also can add critical post-translational modifications similar to those offered by mammalian cell cultures. In this work, by using native GFP and an acid-stable variant of green fluorescent protein (GFP) fused to human monoclonal antibodies, we were able to visualize the entire transient antibody expression and purification process from N. benthamiana plants. Depending on the experiment's purpose, native GFP fusion can ensure easier visualization during the expression phase in the plants, while acid-stable GFP fusion allows for visualization during downstream processing. This scalable and straightforward procedure can be performed by a single researcher to produce milligram quantities of highly pure antibody or antibody fusion proteins in a matter of days using only a few small plants. Such a technique can be extended to the visualization of any type of antibody purification process and potentially many other proteins, both in plant and other expression systems. Moreover, these techniques can benefit virtual instructions and be executed in a teaching laboratory by undergraduate students possessing minimal prior experience with molecular biology techniques, providing a foundation for project-based exploration with real-world applications.


Assuntos
Imunoglobulina G/biossíntese , Nicotiana/genética , Proteínas Recombinantes de Fusão/biossíntese , Agrobacterium tumefaciens/metabolismo , Animais , Anticorpos Monoclonais/metabolismo , Sequência de Bases , Cromatografia , Eletroforese em Gel de Poliacrilamida , Proteínas de Fluorescência Verde/metabolismo , Humanos , Canamicina/farmacologia , Folhas de Planta/microbiologia , Plantas Geneticamente Modificadas , Nicotiana/crescimento & desenvolvimento , Nicotiana/microbiologia , Raios Ultravioleta
2.
Artigo em Inglês | MEDLINE | ID: mdl-32387315

RESUMO

Cocaine use disorders include short-term and acute pathologies (e.g. overdose) and long-term and chronic disorders (e.g. intractable addiction and post-abstinence relapse). There is currently no available treatment that can effectively reduce morbidity and mortality associated with cocaine overdose or that can effectively prevent relapse in recovering addicts. One recently developed approach to treat these problems is the use of enzymes that rapidly break down the active cocaine molecule into inactive metabolites. In particular, rational design and site-directed mutagenesis transformed human serum recombinant butyrylcholinesterase (BChE) into a highly efficient cocaine hydrolase with drastically improved catalytic efficiency toward (-)-cocaine. A current drawback preventing the clinical application of this promising enzyme-based therapy is the lack of a cost-effective production strategy that is also flexible enough to rapidly scale-up in response to continuous improvements in enzyme design. Plant-based expression systems provide a unique solution as this platform is designed for fast scalability, low cost and the advantage of performing eukaryotic protein modifications such as glycosylation. A Plant-derived form of the Cocaine Super Hydrolase (A199S/F227A/S287G/A328W/Y332G) we designate PCocSH protects mice from cocaine overdose, counters the lethal effects of acute cocaine overdose, and prevents reinstatement of extinguished drug-seeking behavior in mice that underwent place conditioning with cocaine. These results demonstrate that the novel PCocSH enzyme may well serve as an effective therapeutic for cocaine use disorders in a clinical setting.


Assuntos
Hidrolases de Éster Carboxílico/uso terapêutico , Transtornos Relacionados ao Uso de Cocaína/tratamento farmacológico , Cocaína/intoxicação , Overdose de Drogas/tratamento farmacológico , Comportamento de Procura de Droga/efeitos dos fármacos , Plantas/química , Proteínas Recombinantes/uso terapêutico , Animais , Butirilcolinesterase/química , Butirilcolinesterase/uso terapêutico , Condicionamento Operante/efeitos dos fármacos , Overdose de Drogas/mortalidade , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nicotiana/química , Nicotiana/metabolismo
4.
Sci Rep ; 8(1): 17223, 2018 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-30443038

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

5.
Sci Rep ; 7(1): 10419, 2017 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-28874829

RESUMO

Butyrylcholinesterase (BChE) is an enzyme with broad substrate and ligand specificities and may function as a generalized bioscavenger by binding and/or hydrolyzing various xenobiotic agents and toxicants, many of which target the central and peripheral nervous systems. Variants of BChE were rationally designed to increase the enzyme's ability to hydrolyze the psychoactive enantiomer of cocaine. These variants were cloned, and then expressed using the magnICON transient expression system in plants and their enzymatic properties were investigated. In particular, we explored the effects that these site-directed mutations have over the enzyme kinetics with various substrates of BChE. We further compared the affinity of various anticholinesterases including organophosphorous nerve agents and pesticides toward these BChE variants relative to the wild type enzyme. In addition to serving as a therapy for cocaine addiction-related diseases, enhanced bioscavenging against other harmful agents could add to the practicality and versatility of the plant-derived recombinant enzyme as a multivalent therapeutic.


Assuntos
Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Cocaína/metabolismo , Proteínas de Plantas , Proteínas Recombinantes , Regulação Alostérica , Sítios de Ligação , Butirilcolinesterase/genética , Domínio Catalítico , Cocaína/química , Variação Genética , Hidrólise , Mutação , Ligação Proteica , Estereoisomerismo
6.
Virology ; 507: 242-256, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28458036

RESUMO

Showing modest efficacy, the RV144 HIV-1 vaccine clinical trial utilized a non-replicating canarypox viral vector and a soluble gp120 protein boost. Here we built upon the RV144 strategy by developing a novel combination of a replicating, but highly-attenuated Vaccinia virus vector, NYVAC-KC, and plant-produced HIV-1 virus-like particles (VLPs). Both components contained the full-length Gag and a membrane anchored truncated gp41 presenting the membrane proximal external region with its conserved broadly neutralizing epitopes in the pre-fusion conformation. We tested different prime/boost combinations of these components in mice and showed that the group primed with NYVAC-KC and boosted with both the viral vectors and plant-produced VLPs have the most robust Gag-specific CD8 T cell responses, at 12.7% of CD8 T cells expressing IFN-γ in response to stimulation with five Gag epitopes. The same immunization group elicited the best systemic and mucosal antibody responses to Gag and dgp41 with a bias towards IgG1.


Assuntos
Vacinas contra a AIDS/administração & dosagem , Proteína gp41 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Imunização/métodos , Nicotiana/metabolismo , Vaccinia virus/fisiologia , Produtos do Gene gag do Vírus da Imunodeficiência Humana/imunologia , Vacinas contra a AIDS/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Formação de Anticorpos , Feminino , Vetores Genéticos/genética , Vetores Genéticos/fisiologia , Anticorpos Anti-HIV/imunologia , Proteína gp41 do Envelope de HIV/administração & dosagem , Proteína gp41 do Envelope de HIV/genética , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , HIV-1/genética , Humanos , Imunização Secundária , Camundongos , Camundongos Endogâmicos C57BL , Nicotiana/genética , Nicotiana/virologia , Vacinas de Partículas Semelhantes a Vírus/genética , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vaccinia virus/genética , Replicação Viral , Produtos do Gene gag do Vírus da Imunodeficiência Humana/administração & dosagem , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética
7.
PLoS One ; 12(2): e0172529, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28225803

RESUMO

Viral protein U (Vpu) is a type-III integral membrane protein encoded by Human Immunodeficiency Virus-1 (HIV- 1). It is expressed in infected host cells and plays several roles in viral progeny escape from infected cells, including down-regulation of CD4 receptors. But key structure/function questions remain regarding the mechanisms by which the Vpu protein contributes to HIV-1 pathogenesis. Here we describe expression of Vpu in bacteria, its purification and characterization. We report the successful expression of PelB-Vpu in Escherichia coli using the leader peptide pectate lyase B (PelB) from Erwinia carotovora. The protein was detergent extractable and could be isolated in a very pure form. We demonstrate that the PelB signal peptide successfully targets Vpu to the cell membranes and inserts it as a type I membrane protein. PelB-Vpu was biophysically characterized by circular dichroism and dynamic light scattering experiments and was shown to be an excellent candidate for elucidating structural models.


Assuntos
Proteínas do Vírus da Imunodeficiência Humana/metabolismo , Proteínas Virais Reguladoras e Acessórias/metabolismo , Clonagem Molecular , Escherichia coli , Expressão Gênica , Proteínas do Vírus da Imunodeficiência Humana/genética , Humanos , Dobramento de Proteína , Sinais Direcionadores de Proteínas , Proteínas Virais Reguladoras e Acessórias/genética
8.
PLoS One ; 11(3): e0151842, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26986483

RESUMO

It is widely anticipated that a prophylactic vaccine may be needed to control the HIV/AIDS epidemic worldwide. Despite over two decades of research, a vaccine against HIV-1 remains elusive, although a recent clinical trial has shown promising results. Recent studies have focused on highly conserved domains within HIV-1 such as the membrane proximal external region (MPER) of the envelope glycoprotein, gp41. MPER has been shown to play critical roles in mucosal transmission of HIV-1, though this peptide is poorly immunogenic on its own. Here we provide evidence that plant-produced HIV-1 enveloped virus-like particles (VLPs) consisting of Gag and a deconstructed form of gp41 comprising the MPER, transmembrane, and cytoplasmic domains (Dgp41) provides an effective platform to display MPER for use as an HIV vaccine candidate. Prime-boost strategies combining systemic and mucosal priming with systemic boosting using two different vaccine candidates (VLPs and CTB-MPR--a fusion of MPER and the B-subunit of cholera toxin) were investigated in BALB/c mice. Serum antibody responses against both the Gag and gp41 antigens were elicited when systemically primed with VLPs. These responses could be recalled following systemic boosting with VLPs. In addition, mucosal priming with VLPs allowed for a boosting response against Gag and gp41 when boosted with either candidate. Importantly, the VLPs also induced Gag-specific CD4 and CD8 T-cell responses. This report on the immunogenicity of plant-based Gag/Dgp41 VLPs may represent an important milestone on the road towards a broadly efficacious and inexpensive subunit vaccine against HIV-1.


Assuntos
Vacinas contra a AIDS/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Nicotiana/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Vacinas de Partículas Semelhantes a Vírus/imunologia , Produtos do Gene gag do Vírus da Imunodeficiência Humana/imunologia , Animais , Formação de Anticorpos/efeitos dos fármacos , Formação de Anticorpos/imunologia , Feminino , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C
9.
PLoS One ; 10(8): e0136507, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26295457

RESUMO

The membrane proximal region (MPR, residues 649-683) and transmembrane domain (TMD, residues 684-705) of the gp41 subunit of HIV-1's envelope protein are highly conserved and are important in viral mucosal transmission, virus attachment and membrane fusion with target cells. Several structures of the trimeric membrane proximal external region (residues 662-683) of MPR have been reported at the atomic level; however, the atomic structure of the TMD still remains unknown. To elucidate the structure of both MPR and TMD, we expressed the region spanning both domains, MPR-TM (residues 649-705), in Escherichia coli as a fusion protein with maltose binding protein (MBP). MPR-TM was initially fused to the C-terminus of MBP via a 42 aa-long linker containing a TEV protease recognition site (MBP-linker-MPR-TM). Biophysical characterization indicated that the purified MBP-linker-MPR-TM protein was a monodisperse and stable candidate for crystallization. However, crystals of the MBP-linker-MPR-TM protein could not be obtained in extensive crystallization screens. It is possible that the 42 residue-long linker between MBP and MPR-TM was interfering with crystal formation. To test this hypothesis, the 42 residue-long linker was replaced with three alanine residues. The fusion protein, MBP-AAA-MPR-TM, was similarly purified and characterized. Significantly, both the MBP-linker-MPR-TM and MBP-AAA-MPR-TM proteins strongly interacted with broadly neutralizing monoclonal antibodies 2F5 and 4E10. With epitopes accessible to the broadly neutralizing antibodies, these MBP/MPR-TM recombinant proteins may be in immunologically relevant conformations that mimic a pre-hairpin intermediate of gp41.


Assuntos
Vacinas contra a AIDS/química , Proteína gp41 do Envelope de HIV/química , HIV-1/imunologia , Fragmentos de Peptídeos/química , Vacinas contra a AIDS/imunologia , Vacinas contra a AIDS/isolamento & purificação , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/imunologia , Proteína gp41 do Envelope de HIV/imunologia , Fragmentos de Peptídeos/imunologia , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/imunologia , Ressonância de Plasmônio de Superfície , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/imunologia , Proteínas Virais de Fusão/isolamento & purificação
10.
Biotechnol Lett ; 37(11): 2147-50, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26149580

RESUMO

OBJECTIVES: This short commentary examines the factors that led to Food and Drug Administration's approval of the first plant-derived biologic. RESULTS: In 2012, the first plant-derived protein pharmaceutical (biologic) was approved for commercial use in humans. The product, a recombinant form of human ß-glucocerebrosidase marketed as ELELYSO, was developed by Protalix Biotherapeutics (Carmiel, Israel). The foresight to select this particular therapeutic product for development, flawless production pipeline, and serendipity seem to provide the key in explaining how ELELYSO became the first plant-derived biologic to achieve approval by Food and Drug Administration. CONCLUSIONS: While the circumstances that enabled Protalix and its scientists to become the first to arrive at this historic milestone are perhaps unique, it is anticipated that more biologics will follow suit in winning regulatory endorsement.


Assuntos
Produtos Biológicos , Agricultura Molecular , Proteínas de Plantas , Glucosilceramidase , Humanos , Estados Unidos , United States Food and Drug Administration
11.
IUCrJ ; 1(Pt 5): 305-17, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25295172

RESUMO

CTB-MPR is a fusion protein between the B subunit of cholera toxin (CTB) and the membrane-proximal region of gp41 (MPR), the transmembrane envelope protein of Human immunodeficiency virus 1 (HIV-1), and has previously been shown to induce the production of anti-HIV-1 antibodies with antiviral functions. To further improve the design of this candidate vaccine, X-ray crystallography experiments were performed to obtain structural information about this fusion protein. Several variants of CTB-MPR were designed, constructed and recombinantly expressed in Escherichia coli. The first variant contained a flexible GPGP linker between CTB and MPR, and yielded crystals that diffracted to a resolution of 2.3 Å, but only the CTB region was detected in the electron-density map. A second variant, in which the CTB was directly attached to MPR, was shown to destabilize pentamer formation. A third construct containing a polyalanine linker between CTB and MPR proved to stabilize the pentameric form of the protein during purification. The purification procedure was shown to produce a homogeneously pure and monodisperse sample for crystallization. Initial crystallization experiments led to pseudo-crystals which were ordered in only two dimensions and were disordered in the third dimension. Nanocrystals obtained using the same precipitant showed promising X-ray diffraction to 5 Šresolution in femtosecond nanocrystallography experiments at the Linac Coherent Light Source at the SLAC National Accelerator Laboratory. The results demonstrate the utility of femtosecond X-ray crystallography to enable structural analysis based on nano/microcrystals of a protein for which no macroscopic crystals ordered in three dimensions have been observed before.

12.
Protein Sci ; 23(11): 1607-18, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25155369

RESUMO

The transmembrane subunit (gp41) of the envelope glycoprotein of HIV-1 associates noncovalently with the surface subunit (gp120) and together they play essential roles in viral mucosal transmission and infection of target cells. The membrane proximal region (MPR) of gp41 is highly conserved and contains epitopes of broadly neutralizing antibodies. The transmembrane (TM) domain of gp41 not only anchors the envelope glycoprotein complex in the viral membrane but also dynamically affects the interactions of the MPR with the membrane. While high-resolution X-ray structures of some segments of the MPR were solved in the past, they represent the post-fusion forms. Structural information on the TM domain of gp41 is scant and at low resolution. Here we describe the design, expression and purification of a protein construct that includes MPR and the transmembrane domain of gp41 (MPR-TMTEV-6His), which reacts with the broadly neutralizing antibodies 2F5 and 4E10 and thereby may represent an immunologically relevant conformation mimicking a prehairpin intermediate of gp41. The expression level of MPR-TMTEV-6His was improved by fusion to the C-terminus of Mistic protein, yielding ∼ 1 mg of pure protein per liter. The isolated MPR-TMTEV-6His protein was biophysically characterized and is a monodisperse candidate for crystallization. This work will enable further investigation into the structure of MPR-TMTEV-6His, which will be important for the structure-based design of a mucosal vaccine against HIV-1.


Assuntos
Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/isolamento & purificação , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Sequência de Aminoácidos , Anticorpos Monoclonais/metabolismo , Anticorpos Antivirais/metabolismo , Proteína gp41 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/metabolismo , Luz , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espalhamento de Radiação , Ressonância de Plasmônio de Superfície
13.
Plant Biotechnol J ; 12(7): 832-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24618259

RESUMO

Plants have a proven track record for the expression of biopharmaceutically interesting proteins. Importantly, plants and mammals share a highly conserved secretory pathway that allows similar folding, assembly and posttranslational modifications of proteins. Human butyrylcholinesterase (BChE) is a highly sialylated, tetrameric serum protein, investigated as a bioscavenger for organophosphorous nerve agents. Expression of recombinant BChE (rBChE) in Nicotiana benthamiana results in accumulation of both monomers as well as assembled oligomers. In particular, we show here that co-expression of BChE with a novel gene-stacking vector, carrying six mammalian genes necessary for in planta protein sialylation, resulted in the generation of rBChE decorated with sialylated N-glycans. The N-glycosylation profile of monomeric rBChE secreted to the apoplast largely resembles the plasma-derived orthologue. In contrast, rBChE purified from total soluble protein extracts was decorated with a significant portion of ER-typical oligomannosidic structures. Biochemical analyses and live-cell imaging experiments indicated that impaired N-glycan processing is due to aberrant deposition of rBChE oligomers in the endoplasmic reticulum or endoplasmic-reticulum-derived compartments. In summary, we show the assembly of rBChE multimers, however, also points to the need for in-depth studies to explain the unexpected subcellular targeting of oligomeric BChE in plants.


Assuntos
Butirilcolinesterase/metabolismo , Nicotiana/metabolismo , Butirilcolinesterase/genética , Butirilcolinesterase/isolamento & purificação , Vetores Genéticos/metabolismo , Glicosilação , Humanos , Plantas Geneticamente Modificadas/metabolismo , Engenharia de Proteínas , Processamento de Proteína Pós-Traducional , Transporte Proteico , Proteínas Recombinantes/metabolismo , Nicotiana/genética
14.
Biotechnol J ; 9(4): 501-10, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24130173

RESUMO

Human butyrylcholinesterase (BChE) is considered a candidate bioscavenger of nerve agents for use in pre- and post-exposure treatment. However, the presence and functional necessity of complex N-glycans (i.e. sialylated structures) is a challenging issue in respect to its recombinant expression. Here we transiently co-expressed BChE cDNA in the model plant Nicotiana benthamiana with vectors carrying the genes necessary for in planta protein sialylation. Site-specific sugar profiling of secreted recombinant BChE (rBChE) collected from the intercellular fluid revealed the presence of mono- and di-sialylated N-glycans, which largely resembles to the plasma-derived orthologue. Attempts to increase that sialylation content of rBChE by the over-expression of an additional glycosylation enzyme that generates branched N-glycans (i.e. ß1,4-N-acetylglucosaminyl-transferase IV), allowed the production of rBChE decorated with tri-sialylated structures (up to 70%). Sialylated and non-sialylated plant-derived rBChE exhibited functional in vitro activity comparable to that of its commercially available equine-derived counterpart. These results demonstrate the ability of plants to generate valuable proteins with designed sialylated glycosylation profiles optimized for therapeutic efficacy. Moreover, the efficient synthesis of carbohydrates present only in minute amounts on the native protein (tri-sialylated N-glycans) facilitates the generation of a product with superior efficacies and/or new therapeutic functions.


Assuntos
Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Butirilcolinesterase/genética , Butiriltiocolina/análise , Butiriltiocolina/metabolismo , Glicosilação , Humanos , Ácido N-Acetilneuramínico , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Engenharia de Proteínas , Proteínas Recombinantes/genética , Nicotiana/genética , Nicotiana/metabolismo
15.
Hum Vaccin Immunother ; 10(10): 3068-73, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25581535

RESUMO

The VLPNPV 2014 Conference that was convened at the Salk institute was the second conference of its kind to focus on advances in production, purification, and delivery of virus-like particles (VLPs) and nanoparticles. Many exciting developments were reported and discussed in this interdisciplinary arena, but here we report specifically on the contributions of plant-based platforms to VLP vaccine technology as reported in the section of the conference devoted to the topic as well in additional presentations throughout the meeting. The increasing popularity of plant production platforms is due to their lower cost, scalability, and lack of contaminating animal pathogens seen with other systems. Reports include production of complex VLPs consisting of 4 proteins expressed at finely-tuned expression levels, a prime-boost strategy for HIV vaccination using plant-made VLPs and a live viral vector, and the characterization and development of plant viral nanoparticles for use in cancer vaccines, drug delivery, and bioimaging.


Assuntos
Vírus Bluetongue/imunologia , Proteínas do Capsídeo/biossíntese , Antígenos do Núcleo do Vírus da Hepatite B/biossíntese , Plantas/metabolismo , Produtos do Gene gag do Vírus da Imunodeficiência Humana/biossíntese , Proteínas do Capsídeo/imunologia , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Humanos , Nanopartículas , Vacinas de Partículas Semelhantes a Vírus/imunologia , Vacinas de Partículas Semelhantes a Vírus/uso terapêutico , Produtos do Gene gag do Vírus da Imunodeficiência Humana/imunologia
16.
PLoS One ; 8(3): e59159, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23536865

RESUMO

BACKGROUND: Concerns about the safety of paralytics such as succinylcholine to facilitate endotracheal intubation limit their use in prehospital and emergency department settings. The ability to rapidly reverse paralysis and restore respiratory drive would increase the safety margin of an agent, thus permitting the pursuit of alternative intubation strategies. In particular, patients who carry genetic or acquired deficiency of butyrylcholinesterase, the serum enzyme responsible for succinylcholine hydrolysis, are susceptible to succinylcholine-induced apnea, which manifests as paralysis, lasting hours beyond the normally brief half-life of succinylcholine. We hypothesized that intravenous administration of plant-derived recombinant BChE, which also prevents mortality in nerve agent poisoning, would rapidly reverse the effects of succinylcholine. METHODS: Recombinant butyrylcholinesterase was produced in transgenic plants and purified. Further analysis involved murine and guinea pig models of succinylcholine toxicity. Animals were treated with lethal and sublethal doses of succinylcholine followed by administration of butyrylcholinesterase or vehicle. In both animal models vital signs and overall survival at specified intervals post succinylcholine administration were assessed. RESULTS: Purified plant-derived recombinant human butyrylcholinesterase can hydrolyze succinylcholine in vitro. Challenge of mice with an LD100 of succinylcholine followed by BChE administration resulted in complete prevention of respiratory inhibition and concomitant mortality. Furthermore, experiments in symptomatic guinea pigs demonstrated extremely rapid succinylcholine detoxification with complete amelioration of symptoms and no apparent complications. CONCLUSIONS: Recombinant plant-derived butyrylcholinesterase was capable of counteracting and reversing apnea in two complementary models of lethal succinylcholine toxicity, completely preventing mortality. This study of a protein antidote validates the feasibility of protection and treatment of overdose from succinylcholine as well as other biologically active butyrylcholinesterase substrates.


Assuntos
Apneia/induzido quimicamente , Apneia/tratamento farmacológico , Butirilcolinesterase/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Succinilcolina/efeitos adversos , Animais , Apneia/prevenção & controle , Catálise , Cobaias , Humanos , Masculino , Camundongos , Especificidade por Substrato , Succinilcolina/metabolismo , Succinilcolina/toxicidade
17.
Plant Mol Biol ; 81(6): 565-76, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23430565

RESUMO

Acetylcholinesterase is an enzyme that is intimately associated with regulation of synaptic transmission in the cholinergic nervous system and in neuromuscular junctions of animals. However the presence of cholinesterase activity has been described also in non-metazoan organisms such as slime molds, fungi and plants. More recently, a gene purportedly encoding for acetylcholinesterase was cloned from maize. We have cloned the Arabidopsis thaliana homolog of the Zea mays gene, At3g26430, and studied its biochemical properties. Our results indicate that the protein encoded by the gene exhibited lipase activity with preference to long chain substrates but did not hydrolyze choline esters. The At3g26430 protein belongs to the SGNH clan of serine hydrolases, and more specifically to the GDS(L) lipase family.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Colinesterases/genética , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lipase/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Colinesterases/metabolismo , Clonagem Molecular , Biologia Computacional/métodos , Ativação Enzimática , Ensaios Enzimáticos , Escherichia coli/genética , Escherichia coli/metabolismo , Genes de Plantas , Hidrólise , Lipase/genética , Dados de Sequência Molecular , Filogenia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , RNA de Plantas/genética , Alinhamento de Sequência , Zea mays/enzimologia , Zea mays/genética
18.
Biochim Biophys Acta ; 1823(2): 368-78, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22093924

RESUMO

Cholinergic signaling suppresses inflammation in blood and brain and attenuates apoptosis in other tissues, but whether it blocks inflammation in skeletal muscle under toxicant exposure, injuries and diseases remained unexplored. Here, we report nicotinic attenuation of inflammation and alteration of apoptotic protein expression pattern in murine muscle tissue and cultured myotubes, involving the RNA-binding protein, Tristetraprolin, and the anti-apoptotic protein, Mcl-1. In muscles and C2C12 myotubes, cholinergic excitation by exposure to nicotine or the organophosphorous pesticide, Paraoxon, induced Tristetraprolin overproduction while reducing pro-inflammatory transcripts such as IL-6, CXCL1 (KC) and CCL2 (MCP-1). Furthermore, nicotinic excitation under exposure to the bacterial endotoxin LPS attenuated over-expression of the CCL2 and suppressed the transcriptional activity of NF-ĸB and AP-1. Tristetraprolin was essential for this anti-inflammatory effect of nicotine in basal conditions. However, its knockdown also impaired the pro-inflammatory response to LPS. Finally, in vivo administration of Paraoxon or recombinant Acetylcholinesterase, leading respectively to either gain or loss of cholinergic signaling, modified muscle expression of key mRNA processing factors and several of their apoptosis-related targets. Specifically, cholinergic imbalances enhanced the kinase activators of the Serine-Arginine splicing kinases, Clk1 and Clk3. Moreover, Paraoxon raised the levels of the anti-apoptotic protein, Mcl-1, through a previously unrecognized polyadenylation site selection mechanism, producing longer, less stable Mcl-1 mRNA transcripts. Together, our findings demonstrate that in addition to activating muscle function, acetylcholine regulates muscle inflammation and cell survival, and point to Tristetraprolin and the choice of Mcl-1 mRNA polyadenylation sites as potential key players in muscle reactions to insults.


Assuntos
Inflamação/patologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/patologia , Músculo Esquelético/fisiologia , Nicotina/farmacologia , Tristetraprolina/metabolismo , Animais , Apoptose/fisiologia , Linhagem Celular , Inibidores da Colinesterase/farmacologia , Citocinas/metabolismo , Perfilação da Expressão Gênica , Inflamação/metabolismo , Masculino , Camundongos , Análise em Microsséries , Proteína de Sequência 1 de Leucemia de Células Mieloides , Agonistas Nicotínicos/farmacologia , Paraoxon/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Tristetraprolina/genética
19.
Vaccine ; 29(34): 5584-90, 2011 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-21693158

RESUMO

The membrane-proximal region spanning residues 649-684 of the HIV-1 envelope protein gp41 (MPR649₋684) is an attractive vaccine target for humoral immunity that blocks viral transcytosis across the mucosal epithelia. However, induction of high-titer MPR649₋684-specific antibodies remains a challenging task. To explore potential solutions for this challenge, we tested a new translational fusion protein comprising the plague F1-V antigen and MPR649₋684 (F1-V-MPR649₋684). We employed systemic immunization for initial feasibility analyses. Despite strong immunogenicity demonstrated for the immunogen, repeated systemic immunizations of mice with F1-V-MPR649₋684 hardly induced MPR649₋684-specific IgG. In contrast, a single immunization with F1-V-MPR649₋684 mounted a significant anti-MPR649₋684 IgG response in animals that were primed with another MPR649₋684 fusion protein based on the cholera toxin B subunit. Additional boost immunizations with F1-V-MPR649₋684 recalled and maintained the antibody response and expanded the number of specific antibody-secreting B cells. Thus, while F1-V-MPR649₋684 alone was not sufficiently immunogenic to induce detectable levels of MPR649₋684-specific antibodies, these results suggest that prime-boost immunization using heterologous antigen-display platforms may overcome the poor humoral immunogenicity of MPR649₋684 for the induction of durable humoral immunity. Further studies are warranted to evaluate the feasibility of this strategy in mucosal immunization. Lastly, our findings add to a growing body of evidence in support of this strategy for immunogen design for poorly immunogenic epitopes besides the MPR of HIV-1's transmembrane envelope protein.


Assuntos
Anticorpos Anti-HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Fragmentos de Peptídeos/imunologia , Proteínas Recombinantes de Fusão/imunologia , Vacinas Virais/imunologia , Animais , Proteínas de Bactérias/imunologia , Toxina da Cólera/imunologia , Ensaio de Imunoadsorção Enzimática , ELISPOT , Imunidade Humoral , Imunização Secundária , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Vacinação
20.
Proc Natl Acad Sci U S A ; 107(47): 20251-6, 2010 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-21059932

RESUMO

The concept of using cholinesterase bioscavengers for prophylaxis against organophosphorous nerve agents and pesticides has progressed from the bench to clinical trial. However, the supply of the native human proteins is either limited (e.g., plasma-derived butyrylcholinesterase and erythrocytic acetylcholinesterase) or nonexisting (synaptic acetylcholinesterase). Here we identify a unique form of recombinant human butyrylcholinesterase that mimics the native enzyme assembly into tetramers; this form provides extended effective pharmacokinetics that is significantly enhanced by polyethylene glycol conjugation. We further demonstrate that this enzyme (but not a G117H/E197Q organophosphorus acid anhydride hydrolase catalytic variant) can prevent morbidity and mortality associated with organophosphorous nerve agent and pesticide exposure of animal subjects of two model species.


Assuntos
Butirilcolinesterase/farmacologia , Substâncias para a Guerra Química/toxicidade , Fármacos Neuroprotetores/farmacologia , Nicotiana/metabolismo , Compostos Organofosforados/toxicidade , Praguicidas/toxicidade , Animais , Butirilcolinesterase/metabolismo , Butirilcolinesterase/farmacocinética , Substâncias para a Guerra Química/metabolismo , Cromatografia Líquida de Alta Pressão , Cobaias , Humanos , Immunoblotting , Cinética , Camundongos , Fármacos Neuroprotetores/metabolismo , Fármacos Neuroprotetores/farmacocinética , Compostos Organofosforados/metabolismo , Praguicidas/metabolismo , Polietilenoglicóis/metabolismo , Engenharia de Proteínas
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