Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 14(1): 4495, 2024 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-38402260

RESUMO

Extrapulmonary tuberculosis with a renal involvement can be a manifestation of a disseminated infection that requires therapeutic intervention, particularly with a decrease in efficacy of conventional regimens. In the present study, we investigated the therapeutic potency of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in the complex anti-tuberculosis treatment (ATT). A rabbit model of renal tuberculosis (rTB) was constructed by injecting of the standard strain Mycobacterium tuberculosis H37Rv into the cortical layer of the kidney parenchyma. Isolated rabbit MSC-EVs were intravenously administered once as an addition to standard ATT (isoniazid, pyrazinamide, and ethambutol). The therapeutic efficacy was assessed by analyzing changes of blood biochemical biomarkers and levels of anti- and pro-inflammatory cytokines as well as by renal computed tomography with subsequent histological and morphometric examination. The therapeutic effect of therapy with MSC-EVs was shown by ELISA method that confirmed a statistically significant increase of the anti-inflammatory and decrease of pro-inflammatory cytokines as compared to conventional treatment. In addition, there is a positive trend in increase of ALP level, animal weigh, and normalization of ADA activity that can indicate an improvement of kidney state. A significant reduction of the area of specific and interstitial inflammation indicated positive affect of MSC-EVs that suggests a shorter duration of ATT. The number of MSC-EVs proteins (as identified by mass-spectometry analysis) with anti-microbial, anti-inflammatory and immunoregulatory functions reduced the level of the inflammatory response and the severity of kidney damage (further proved by morphometric analysis). In conclusion, MSC-EVs can be a promising tool for the complex treatment of various infectious diseases, in particularly rTB.


Assuntos
Vesículas Extracelulares , Células-Tronco Mesenquimais , Tuberculose Renal , Animais , Coelhos , Tuberculose Renal/metabolismo , Vesículas Extracelulares/metabolismo , Citocinas/metabolismo , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios/metabolismo , Células-Tronco Mesenquimais/metabolismo
2.
Int J Biol Sci ; 18(14): 5345-5368, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36147480

RESUMO

Mesenchymal stromal cells (MSC) are widely recognized as potential effectors in neuroprotective therapy. The protective properties of MSC were considered to be associated with the secretion of extracellular vesicles (MSC-EV). We explored the effects of MSC-EV in vivo on models of traumatic and hypoxia-ischemia (HI) brain injury. Neuroprotective mechanisms triggered by MSC-EV were also studied in vitro using a primary neuroglial culture. Intranasal administration of MSC-EV reduced the volume of traumatic brain damage, correlating with a recovery of sensorimotor functions. Neonatal HI-induced brain damage was mitigated by the MSC-EV administration. This therapy also promoted the recovery of sensorimotor functions, implying enhanced neuroplasticity, and MSC-EV-induced growth of neurites in vitro supports this. In the in vitro ischemic model, MSC-EV prevented cell calcium (Ca2+) overload and subsequent cell death. In mixed neuroglial culture, MSC-EV induced inositol trisphosphate (IP3) receptor-related Ca2+ oscillations in astrocytes were associated with resistance to calcium overload not only in astrocytes but also in co-cultured neurons, demonstrating intercellular positive crosstalk between neural cells. This implies that phosphatidylinositol 3-Kinase/AKT signaling is one of the main pathways in MSC-EV-mediated protection of neural cells exposed to ischemic challenge. Components of this pathway were identified among the most enriched categories in the MSC-EV proteome.


Assuntos
Vesículas Extracelulares , Hipóxia-Isquemia Encefálica , Células-Tronco Mesenquimais , Animais , Cálcio/metabolismo , Sinalização do Cálcio , Vesículas Extracelulares/metabolismo , Humanos , Hipóxia-Isquemia Encefálica/metabolismo , Recém-Nascido , Inositol/metabolismo , Isquemia/terapia , Células-Tronco Mesenquimais/metabolismo , Neuroproteção , Fosfatidilinositol 3-Quinases/metabolismo , Proteoma/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo
3.
Stud Health Technol Inform ; 285: 193-198, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34734873

RESUMO

Endometrial cancer (EC) is the most common gynecological tumor in high-income countries, and its incidence has increased over time. The most critical risk factor for EC is the long-term unopposed exposure to increased estrogens both exogenous and endogenous. Machine learning can be used as a promising tool to resolve longstanding challenges and support identification of the risk factors and their correlations before the clinical trials and make them more focused. In this paper we present the results of the research of the correlation analysis of Endometrial cancer risk factors. The study was performed with EC patients of the Almazov center in Saint-Petersburg, Russia. All women involved in the current study underwent radical surgical intervention due to EC. After initial cancer treatment, they were referred to the Almazov center outpatient specialists for follow-up visits. Many of them were readmitted of the inpatient clinic due to relapse. We extracted a variety of parameters related to lifestyle, dietary habits, socioeconomic, and reproductive features from the inpatient and outpatient databases of Almazov center. The medical records of the women with enough data were included in the study. Prediction of Progression-free survival (PFS) and overall survival (OS) were analyzed respectively. The AUC of ROC was calculated for PFS = 0.93 and for OS = 0.94.


Assuntos
Neoplasias do Endométrio , Doença Crônica , Dieta Vegetariana , Feminino , Humanos , Estilo de Vida , Recidiva
4.
Mol Cell ; 81(8): 1749-1765.e8, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33657400

RESUMO

Acetylation of lysine 16 on histone H4 (H4K16ac) is catalyzed by histone acetyltransferase KAT8 and can prevent chromatin compaction in vitro. Although extensively studied in Drosophila, the functions of H4K16ac and two KAT8-containing protein complexes (NSL and MSL) are not well understood in mammals. Here, we demonstrate a surprising complex-dependent activity of KAT8: it catalyzes H4K5ac and H4K8ac as part of the NSL complex, whereas it catalyzes the bulk of H4K16ac as part of the MSL complex. Furthermore, we show that MSL complex proteins and H4K16ac are not required for cell proliferation and chromatin accessibility, whereas the NSL complex is essential for cell survival, as it stimulates transcription initiation at the promoters of housekeeping genes. In summary, we show that KAT8 switches catalytic activity and function depending on its associated proteins and that, when in the NSL complex, it catalyzes H4K5ac and H4K8ac required for the expression of essential genes.


Assuntos
Histona Acetiltransferases/genética , Homeostase/genética , Transcrição Gênica/genética , Acetilação , Animais , Linhagem Celular , Linhagem Celular Tumoral , Núcleo Celular/genética , Proliferação de Células/genética , Cromatina/genética , Células HEK293 , Células HeLa , Histonas/genética , Humanos , Células K562 , Lisina/genética , Masculino , Camundongos , Regiões Promotoras Genéticas/genética , Células THP-1
5.
Plant Mol Biol ; 106(1-2): 123-143, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33713297

RESUMO

Plants utilize a plethora of peptide signals to regulate their immune response. Peptide ligands and their cognate receptors involved in immune signaling share common motifs among many species of vascular plants. However, the origin and evolution of immune peptides is still poorly understood. Here, we searched for genes encoding small secreted peptides in the genomes of three bryophyte lineages-mosses, liverworts and hornworts-that occupy a critical position in the study of land plant evolution. We found that bryophytes shared common predicted small secreted peptides (SSPs) with vascular plants. The number of SSPs is higher in the genomes of mosses than in both the liverwort Marchantia polymorpha and the hornwort Anthoceros sp. The synthetic peptide elicitors-AtPEP and StPEP-specific for vascular plants, triggered ROS production in the protonema of the moss Physcomitrella patens, suggesting the possibility of recognizing peptide ligands from angiosperms by moss receptors. Mass spectrometry analysis of the moss Physcomitrella patens, both the wild type and the Δcerk mutant secretomes, revealed peptides that specifically responded to chitosan treatment, suggesting their role in immune signaling.


Assuntos
Bryopsida/imunologia , Bryopsida/metabolismo , Peptídeos/metabolismo , Imunidade Vegetal , Transdução de Sinais , Sequência de Aminoácidos , Bryopsida/efeitos dos fármacos , Bryopsida/genética , Quitosana/farmacologia , Genoma de Planta , Peptídeos/química , Imunidade Vegetal/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
6.
Stud Health Technol Inform ; 270: 342-346, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32570403

RESUMO

Developing predictive modeling in medicine requires additional features from unstructured clinical texts. In Russia, there are no instruments for natural language processing to cope with problems of medical records. This paper is devoted to a module of negation detection. The corpus-free machine learning method is based on gradient boosting classifier is used to detect whether a disease is denied, not mentioned or presented in the text. The detector classifies negations for five diseases and shows average F-score from 0.81 to 0.93. The benefits of negation detection have been demonstrated by predicting the presence of surgery for patients with the acute coronary syndrome.


Assuntos
Mineração de Dados , Processamento de Linguagem Natural , Registros Eletrônicos de Saúde , Idioma , Aprendizado de Máquina , Federação Russa
7.
Int J Mol Sci ; 22(1)2020 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-33396968

RESUMO

Despite the world's combined efforts, human immunodeficiency virus (HIV), the causative agent of AIDS, remains one of the world's most serious public health challenges. High genetic variability of HIV complicates the development of anti-HIV vaccine, and there is an actual clinical need for increasing the efficiency of anti-HIV drugs in terms of targeted delivery and controlled release. Tenofovir (TFV), a nucleotide-analog reverse transcriptase inhibitor, has gained wide acceptance as a drug for pre-exposure prophylaxis or treatment of HIV infection. In our study, we explored the potential of tenofovir disoproxil (TFD) adducts with block copolymers of poly(ethylene glycol) monomethyl ether and poly(ethylene phosphoric acid) (mPEG-b-PEPA) as candidates for developing a long-acting/controlled-release formulation of TFV. Two types of mPEG-b-PEPA with numbers of ethylene phosphoric acid (EPA) fragments of 13 and 49 were synthesized by catalytic ring-opening polymerization, and used for preparing four types of adducts with TFD. Antiviral activity of [mPEG-b-PEPA]TFD or tenofovir disoproxil fumarate (TDF) was evaluated using the model of experimental HIV infection in vitro (MT-4/HIV-1IIIB). Judging by the values of the selectivity index (SI), TFD exhibited an up to 14-fold higher anti-HIV activity in the form of mPEG-b-PEPA adducts, thus demonstrating significant promise for further development of long-acting/controlled-release injectable TFV formulations.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Polímeros/química , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Tenofovir/administração & dosagem , Fármacos Anti-HIV/farmacologia , Infecções por HIV/patologia , Infecções por HIV/virologia , Humanos , Ácidos Fosfóricos/química , Polietileno/química , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/virologia , Tenofovir/farmacologia , Células Tumorais Cultivadas
8.
Nat Struct Mol Biol ; 26(11): 999-1012, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31611688

RESUMO

Protein arginine methyltransferase 5 (PRMT5) has emerged as a promising cancer drug target, and three PRMT5 inhibitors are currently in clinical trials for multiple malignancies. In this study, we investigated the role of PRMT5 in human acute myeloid leukemia (AML). Using an enzymatic dead version of PRMT5 and a PRMT5-specific inhibitor, we demonstrated the requirement of the catalytic activity of PRMT5 for the survival of AML cells. We then identified PRMT5 substrates using multiplexed quantitative proteomics and investigated their role in the survival of AML cells. We found that the function of the splicing regulator SRSF1 relies on its methylation by PRMT5 and that loss of PRMT5 leads to changes in alternative splicing of multiple essential genes. Our study proposes a mechanism for the requirement of PRMT5 for leukemia cell survival and provides potential biomarkers for the treatment response to PRMT5 inhibitors.


Assuntos
Leucemia Mieloide Aguda/enzimologia , Proteínas de Neoplasias/fisiologia , Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/fisiologia , Splicing de RNA , Animais , Antineoplásicos/farmacologia , Arginina/análogos & derivados , Arginina/biossíntese , Arginina/metabolismo , Catálise , Linhagem Celular Tumoral , Sobrevivência Celular , Inibidores Enzimáticos/farmacologia , Regulação Leucêmica da Expressão Gênica , Humanos , Leucemia Mieloide Aguda/genética , Metilação , Camundongos , Terapia de Alvo Molecular , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Proteínas de Fusão Oncogênica/genética , Processamento de Proteína Pós-Traducional/genética , Proteína-Arginina N-Metiltransferases/antagonistas & inibidores , Proteína-Arginina N-Metiltransferases/deficiência , Proteômica , Fatores de Processamento de Serina-Arginina/metabolismo
9.
Methods Mol Biol ; 2044: 111-118, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31432409

RESUMO

Proteo-peptidomic profiling of biofluids is used to identify disease biomarkers and to study molecular mechanisms of pathology development. Previously, we studied changes in cerebrospinal fluid (CSF) and blood plasma associated with Guillain-Barre syndrome (GBS)-a rare and severe disorder of the peripheral nervous system with an unknown etiology. Here, we describe the workflow for the analysis of endogenous peptides from CSF. The procedure covers sample preparation, liquid chromatography-mass spectrometry (LC-MS) analysis, and bioinformatics analysis and allows identification of more than 1100 peptides from 181 protein groups in ~3 h from a single CSF sample derived from non-neurological, non-oncological patients.


Assuntos
Proteínas do Líquido Cefalorraquidiano/isolamento & purificação , Peptídeos/líquido cefalorraquidiano , Peptídeos/isolamento & purificação , Proteômica/métodos , Biomarcadores/líquido cefalorraquidiano , Proteínas do Líquido Cefalorraquidiano/análise , Proteínas do Líquido Cefalorraquidiano/química , Proteínas do Líquido Cefalorraquidiano/metabolismo , Cromatografia Líquida/métodos , Biologia Computacional , Humanos , Espectrometria de Massas em Tandem , Fluxo de Trabalho
10.
Nucleic Acids Res ; 46(17): 8966-8977, 2018 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-30102362

RESUMO

Several studies have described functional peptides encoded in RNA that are considered to be noncoding. Telomerase RNA together with telomerase reverse transcriptase and regulatory proteins make up the telomerase complex, the major component of the telomere length-maintaining machinery. In contrast to protein subunits, telomerase RNA is expressed constitutively in most somatic cells where telomerase reverse transcriptase is absent. We show here that the transcript of human telomerase RNA codes a 121 amino acid protein (hTERP). The existence of hTERP was shown by immunoblotting, immunofluorescence microscopy and mass spectroscopy. Gain-of-function and loss-of-function experiments showed that hTERP protects cells from drug-induced apoptosis and participates in the processing of autophagosome. We suggest that hTERP regulates crosstalk between autophagy and apoptosis and is involved in cellular adaptation under stress conditions.


Assuntos
Adaptação Fisiológica/genética , Apoptose/genética , Autofagia/genética , RNA Mensageiro/genética , RNA/genética , Telomerase/genética , Telômero/metabolismo , Sequência de Aminoácidos , Animais , Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Autofagossomos/efeitos dos fármacos , Autofagossomos/metabolismo , Autofagia/efeitos dos fármacos , Gatos , Linhagem Celular Tumoral , Clonagem Molecular , Doxorrubicina/farmacologia , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação da Expressão Gênica , Células HEK293 , Cavalos , Humanos , Células Jurkat , Camundongos , RNA/metabolismo , RNA Mensageiro/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Estresse Fisiológico , Telomerase/metabolismo , Telômero/química , Homeostase do Telômero
11.
J Membr Biol ; 251(5-6): 633-640, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29995247

RESUMO

In contrast to the parent pentadecapeptide gramicidin A (gA), some of its cationic analogs have been shown previously to form large-diameter pores in lipid membranes. These pores are permeable to fluorescent dyes, which allows one to monitor pore formation by using the fluorescence de-quenching assay. According to the previously proposed model, the gA analog with lysine substituted for alanine at position 3, [Lys3]gA, forms pores by a homopentameric assembly of gramicidin double-stranded ß-helical dimers. Here, we studied the newly synthesized analogs of [Lys3]gA with single, double and triple substitutions of isoleucines for tryptophans at positions 9, 11, 13, and 15. Replacement of any of the tryptophans of [Lys3]gA with isoleucine resulted in suppression of the pore-forming activity of the peptide, the effect being significantly dependent on the position of tryptophans. In particular, the peptide with a single substitution of tryptophan 13 showed much lower activity than the analogs with single substitutions at positions 9, 11, or 15. Of the peptides with double substitutions, the strongest suppression of the leakage was observed with tryptophans 13 and 15. In the case of triple substitutions, only the peptide retaining tryptophan 11 exhibited noticeable activity. It is concluded that tryptophans 11 and 13 contribute most to pore stabilization in the membrane, whereas tryptophan 9 is not so important for pore formation. Cation-π interactions between the lysine and tryptophan residues of the peptide are suggested to be crucial for the formation of the [Lys3]gA pore.


Assuntos
Gramicidina/química , Lipossomos/química , Lisina/química , Lipídeos de Membrana/química , Peptídeos/química , Triptofano/química
12.
Mol Cell Proteomics ; 17(8): 1591-1611, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29784711

RESUMO

Streptomycetes are multicellular bacteria with complex developmental cycles. They are of biotechnological importance as they produce most bioactive compounds used in biomedicine, e.g. antibiotic, antitumoral and immunosupressor compounds. Streptomyces genomes encode many Ser/Thr/Tyr kinases, making this genus an outstanding model for the study of bacterial protein phosphorylation events. We used mass spectrometry based quantitative proteomics and phosphoproteomics to characterize bacterial differentiation and activation of secondary metabolism of Streptomyces coelicolor We identified and quantified 3461 proteins corresponding to 44.3% of the S. coelicolor proteome across three developmental stages: vegetative hypha (first mycelium); secondary metabolite producing hyphae (second mycelium); and sporulating hyphae. A total of 1350 proteins exhibited more than 2-fold expression changes during the bacterial differentiation process. These proteins include 136 regulators (transcriptional regulators, transducers, Ser/Thr/Tyr kinases, signaling proteins), as well as 542 putative proteins with no clear homology to known proteins which are likely to play a role in differentiation and secondary metabolism. Phosphoproteomics revealed 85 unique protein phosphorylation sites, 58 of them differentially phosphorylated during differentiation. Computational analysis suggested that these regulated protein phosphorylation events are implicated in important cellular processes, including cell division, differentiation, regulation of secondary metabolism, transcription, protein synthesis, protein folding and stress responses. We discovered a novel regulated phosphorylation site in the key bacterial cell division protein FtsZ (pSer319) that modulates sporulation and regulates actinorhodin antibiotic production. We conclude that manipulation of distinct protein phosphorylation events may improve secondary metabolite production in industrial streptomycetes, including the activation of cryptic pathways during the screening for new secondary metabolites from streptomycetes.


Assuntos
Proteínas de Bactérias/metabolismo , Fosfoproteínas/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Metabolismo Secundário , Streptomyces coelicolor/metabolismo , Humanos , Micélio/metabolismo , Fenótipo , Fosfopeptídeos/química , Fosfopeptídeos/metabolismo , Fosforilação , Transdução de Sinais , Esporos Bacterianos/metabolismo , Streptomyces coelicolor/genética , Fatores de Tempo , Transcrição Gênica , Regulação para Cima
13.
Sci Rep ; 7(1): 14534, 2017 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-29109403

RESUMO

Sea anemones (Actiniaria) are intensely popular objects of study in venomics. Order Actiniaria includes more than 1,000 species, thus presenting almost unlimited opportunities for the discovery of novel biologically active molecules. The venoms of cold-water sea anemones are studied far less than the venoms of tropical sea anemones. In this work, we analysed the molecular venom composition of the cold-water sea anemone Cnidopus japonicus. Two sets of NGS data from two species revealed molecules belonging to a variety of structural classes, including neurotoxins, toxin-like molecules, linear polypeptides (Cys-free), enzymes, and cytolytics. High-throughput proteomic analyses identified 27 compounds that were present in the venoms. Some of the toxin-like polypeptides exhibited novel Cys frameworks. To characterise their function in the venom, we heterologously expressed 3 polypeptides with unusual Cys frameworks (designated CjTL7, CjTL8, and AnmTx Cj 1c-1) in E. coli. Toxicity tests revealed that the CjTL8 polypeptide displays strong crustacean-specific toxicity, while AnmTx Cj 1c-1 is toxic to both crustaceans and insects. Thus, an improved NGS data analysis algorithm assisted in the identification of toxins with unusual Cys frameworks showing no homology according to BLAST. Our study shows the advantage of combining omics analysis with functional tests for active polypeptide discovery.


Assuntos
Venenos de Cnidários/química , Peptídeos/isolamento & purificação , Anêmonas-do-Mar , Animais , Venenos de Cnidários/genética , Peptídeos/análise , Anêmonas-do-Mar/química , Anêmonas-do-Mar/genética , Alinhamento de Sequência
14.
Sci Rep ; 7(1): 11330, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28900116

RESUMO

Despite the fact the term "proteome" was proposed to characterize a set of proteins in one of mycoplasma species, proteome response to various exposures in this bacteria are still obscure. Commonly, authors studying proteomic response on perturbation models in mycoplasmas use single approach and do not confirm their findings by alternative methods. Consequently, the results of proteomic analysis should be validated by complementary techniques. In this study we utilized three complementary approaches (SWATH, MRM, 2D-DIGE) to assess response of Mycoplasma gallisepticum under heat stress on proteomic level and combined these findings with metabolic response and the results of transcriptional profiling. We divide response into two modes - one is directly related to heat stress and other is triggered during heat stress, but not directly relevant to it. The latter includes accumulation of ATP and shedding of antigens. Both of these phenomena may be relevant to evasion of host's immune system and dissemination during mycoplasmosis in vivo.


Assuntos
Resposta ao Choque Térmico , Infecções por Mycoplasma/microbiologia , Mycoplasma gallisepticum/fisiologia , Trifosfato de Adenosina/metabolismo , Biologia Computacional/métodos , Testes de Hemaglutinação , Metaboloma , Metabolômica , Temperatura , Terpenos/metabolismo
15.
Protein Sci ; 26(3): 611-616, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27997708

RESUMO

We have recently demonstrated that a common phenomenon in evolution of spider venom composition is the emergence of so-called modular toxins consisting of two domains, each corresponding to a "usual" single-domain toxin. In this article, we describe the structure of two domains that build up a modular toxin named spiderine or OtTx1a from the venom of Oxyopes takobius. Both domains were investigated by solution NMR in water and detergent micelles used to mimic membrane environment. The N-terminal spiderine domain OtTx1a-AMP (41 amino acid residues) contains no cysteines. It is disordered in aqueous solution but in micelles, it assumes a stable amphiphilic structure consisting of two α-helices separated by a flexible linker. On the contrary, the C-terminal domain OtTx1a-ICK (59 residues) is a disulfide-rich polypeptide reticulated by five S-S bridges. It presents a stable structure in water and its core is the inhibitor cystine knot (ICK) or knottin motif that is common among single-domain neurotoxins. OtTx1a-ICK structure is the first knottin with five disulfide bridges and it represents a good reference for the whole oxytoxin family. The affinity of both domains to membranes was measured with NMR using titration by liposome suspensions. In agreement with biological tests, OtTx1a-AMP was found to show high membrane affinity explaining its potent antimicrobial properties.


Assuntos
Proteínas de Artrópodes/química , Membranas Artificiais , Venenos de Aranha/química , Aranhas/química , Animais , Ressonância Magnética Nuclear Biomolecular , Domínios Proteicos
16.
Biochem J ; 473(16): 2495-506, 2016 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-27287558

RESUMO

In the present study, we show that venom of the ant spider Lachesana tarabaevi is unique in terms of molecular composition and toxicity. Whereas venom of most spiders studied is rich in disulfide-containing neurotoxic peptides, L. tarabaevi relies on the production of linear (no disulfide bridges) cytolytic polypeptides. We performed full-scale peptidomic examination of L. tarabaevi venom supported by cDNA library analysis. As a result, we identified several dozen components, and a majority (∼80% of total venom protein) exhibited membrane-active properties. In total, 33 membrane-interacting polypeptides (length of 18-79 amino acid residues) comprise five major groups: repetitive polypeptide elements (Rpe), latarcins (Ltc), met-lysines (MLys), cyto-insectotoxins (CIT) and latartoxins (LtTx). Rpe are short (18 residues) amphiphilic molecules that are encoded by the same genes as antimicrobial peptides Ltc 4a and 4b. Isolation of Rpe confirms the validity of the iPQM (inverted processing quadruplet motif) proposed to mark the cleavage sites in spider toxin precursors that are processed into several mature chains. MLys (51 residues) present 'idealized' amphiphilicity when modelled in a helical wheel projection with sharply demarcated sectors of hydrophobic, cationic and anionic residues. Four families of CIT (61-79 residues) are the primary weapon of the spider, accounting for its venom toxicity. Toxins from the CIT 1 and 2 families have a modular structure consisting of two shorter Ltc-like peptides. We demonstrate that in CIT 1a, these two parts act in synergy when they are covalently linked. This finding supports the assumption that CIT have evolved through the joining of two shorter membrane-active peptides into one larger molecule.


Assuntos
Venenos de Aranha/toxicidade , Sequência de Aminoácidos , Animais , Antibacterianos/farmacologia , Membrana Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , DNA Complementar , Bases de Dados Genéticas , Feminino , Inseticidas/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Peso Molecular , Estrutura Secundária de Proteína , Sarcofagídeos/efeitos dos fármacos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Venenos de Aranha/química , Venenos de Aranha/genética , Aranhas
17.
Toxins (Basel) ; 8(4): 105, 2016 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-27077884

RESUMO

Venoms of most Russian viper species are poorly characterized. Here, by quantitative chromato-mass-spectrometry, we analyzed protein and peptide compositions of venoms from four Vipera species (V. kaznakovi, V. renardi, V. orlovi and V. nikolskii) inhabiting different regions of Russia. In all these species, the main components were phospholipases A2, their content ranging from 24% in V. orlovi to 65% in V. nikolskii. Altogether, enzyme content in venom of V. nikolskii reached ~85%. Among the non-enzymatic proteins, the most abundant were disintegrins (14%) in the V. renardi venom, C-type lectin like (12.5%) in V. kaznakovi, cysteine-rich venom proteins (12%) in V. orlovi and venom endothelial growth factors (8%) in V. nikolskii. In total, 210 proteins and 512 endogenous peptides were identified in the four viper venoms. They represented 14 snake venom protein families, most of which were found in the venoms of Vipera snakes previously. However, phospholipase B and nucleotide degrading enzymes were reported here for the first time. Compositions of V. kaznakovi and V. orlovi venoms were described for the first time and showed the greatest similarity among the four venoms studied, which probably reflected close relationship between these species within the "kaznakovi" complex.


Assuntos
Fosfolipases A2/análise , Proteínas de Répteis/análise , Venenos de Víboras/química , Viperidae , Animais , Proteômica
18.
Anal Chim Acta ; 893: 57-64, 2015 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-26398423

RESUMO

Non-specific binding (NSB) is a well-known problem for any application that deals with ultralow analyte quantities. The modern nano-flow chromatography coupled tandem mass-spectrometry (nanoLC-MS/MS) works with the lowest conceivable analyte concentrations. However, while the NSB problem is widely accepted and investigated for metabolomics and single-peptide medicine-related assays, its impact is not studied for complex peptide mixtures in proteomic applications. In this work peptide NSB to a common plastic autosampler vial was studied for a model mixture of 46 synthetic peptides. A significant NSB level was demonstrated for total peptide concentrations of up to 1 mg mL(-1). Different agents were tried for NSB suppression and compatibility with nanoLC-MS/MS analysis: a chaotropic agent, an amino acid mixture, a peptide mixture and a protein solution. The first two were inefficacious. The peptide matrix blocked NSB, however, it also led to analyte ionization suppression in nanoLC-MS/MS. The protein solution (0.1% BSA) efficiently eliminated NSB, while a trap-elute nanoHPLC configuration together with a small-pore reverse-phased sorbent effectively and quantitatively extracted the model peptides and depleted protein material from the sample. Higher protein concentration partially impeded peptide extraction. Thus, the 0.1% BSA solution might be regarded as an effective non-interfering blockader of NSB for sample resuspension and storage in an autosampler prior to LC-MS/MS analysis.


Assuntos
Cromatografia Líquida de Alta Pressão , Peptídeos/química , Soroalbumina Bovina/química , Espectrometria de Massas em Tandem , Aminoácidos/química , Animais , Bovinos , Detergentes/química , Interações Hidrofóbicas e Hidrofílicas , Nanotecnologia , Peptídeos/síntese química , Peptídeos/metabolismo , Ligação Proteica , Proteômica , Soroalbumina Bovina/metabolismo
19.
Microb Pathog ; 83-84: 47-56, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25998017

RESUMO

The fragilysin (BFT) is a protein secreted by enterotoxigenic Bacteroides fragilis strains. BFT contains zinc-binding motif which was found in the metzincins family of metalloproteinases. In this study, we generated three known recombinant isoforms of BFT using Escherichia coli, tested their activity and examined whether E-cadherin is a substrate for BFTs. BFT treatment of HT-29 cells induced endogenous E-cadherin cleavage, and this BFT activity requires the native structure of zinc-binding motif. At the same time recombinant BFTs did not cleave recombinant E-cadherin or E-cadherin in isolated cell fractions. It indicates that E-cadherin may be not direct substrate for BFT. We also detected and identified proteins released into the cultural medium after HT-29 cells treatment with BFT. The role of these proteins in pathogenesis and cell response to BFT remains to be determined.


Assuntos
Caderinas/metabolismo , Metaloendopeptidases/metabolismo , Isoformas de Proteínas/metabolismo , Bacteroides fragilis/enzimologia , Bacteroides fragilis/genética , Linhagem Celular , Células Epiteliais/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Metaloendopeptidases/genética , Isoformas de Proteínas/genética , Proteólise , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
20.
BMC Plant Biol ; 15: 87, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-25848929

RESUMO

BACKGROUND: Protein degradation is a basic cell process that operates in general protein turnover or to produce bioactive peptides. However, very little is known about the qualitative and quantitative composition of a plant cell peptidome, the actual result of this degradation. In this study we comprehensively analyzed a plant cell peptidome and systematically analyzed the peptide generation process. RESULTS: We thoroughly analyzed native peptide pools of Physcomitrella patens moss in two developmental stages as well as in protoplasts. Peptidomic analysis was supplemented by transcriptional profiling and quantitative analysis of precursor proteins. In total, over 20,000 unique endogenous peptides, ranging in size from 5 to 78 amino acid residues, were identified. We showed that in both the protonema and protoplast states, plastid proteins served as the main source of peptides and that their major fraction formed outside of chloroplasts. However, in general, the composition of peptide pools was very different between these cell types. In gametophores, stress-related proteins, e.g., late embryogenesis abundant proteins, were among the most productive precursors. The Driselase-mediated protonema conversion to protoplasts led to a peptide generation "burst", with a several-fold increase in the number of components in the latter. Degradation of plastid proteins in protoplasts was accompanied by suppression of photosynthetic activity. CONCLUSION: We suggest that peptide pools in plant cells are not merely a product of waste protein degradation, but may serve as important functional components for plant metabolism. We assume that the peptide "burst" is a form of biotic stress response that might produce peptides with antimicrobial activity from originally functional proteins. Potential functions of peptides in different developmental stages are discussed.


Assuntos
Bryopsida/citologia , Bryopsida/metabolismo , Células Germinativas Vegetais/citologia , Células Germinativas Vegetais/metabolismo , Peptídeos/metabolismo , Células Vegetais/metabolismo , Protoplastos/citologia , Bryopsida/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Fotossíntese , Proteínas de Plantas/metabolismo , Proteoma/metabolismo , Protoplastos/metabolismo , Alinhamento de Sequência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA