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1.
PLoS One ; 15(10): e0238609, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33112881

RESUMO

INTRODUCTION: Although immune responses to the Japanese Encephalitis virus (JEV), and the dengue viruses (DENV) have a potential to modulate the immune responses to each other, this has been poorly investigated. Therefore, we developed an ELISA to identify JEV specific, DENV non cross-reactive antibody responses by identifying JEV specific, highly conserved regions of the virus and proceeded to investigate if the presence of JEV specific antibodies associate with dengue disease severity. METHODOLOGY AND RESULTS: 22 JEV specific peptides were identified from highly conserved regions of the virus and the immunogenicity and specificity of these peptides were assessed in individuals who were non-immune to JEV and DENV (JEV-DENV-, N = 30), those who were only immune to the JEV and not DENV (JEV+DENV-, N = 30), those who were only immune to DENV(JEV-DENV+, N = 30) and in those who were immune to both viruses (JEV+DENV+, N = 30). 7/22 peptides were found to be highly immunogenic and specific and these 7 peptides were used as a pool to further evaluate JEV-specific responses. All 30/30 JEV+DENV- and 30/30 JEV+DENV+ individuals, and only 3/30 (10%) JEV-DENV+ individuals responded to this pool. We further evaluated this pool of 7 peptides in patients following primary and secondary dengue infection during the convalescent period and found that the JEV-specific peptides, were unlikely to cross react with DENV IgG antibodies. We further compared this in-house ELISA developed with the peptide pool with an existing commercial JEV IgG assay to identify JEV-specific IgG following vaccination, and our in-house ELISA was found to be more sensitive. We then proceeded to investigate if the presence of JEV-specific antibodies were associated with dengue disease severity, and we found that those who had past severe dengue (n = 175) were significantly more likely (p<0.0001) to have JEV-specific antibodies than those with past non-severe dengue (n = 175) (OR 5.3, 95% CI 3.3 to 8.3). CONCLUSIONS: As our data show that this assay is highly sensitive and specific for detection of JEV-specific antibody responses, it would be an important tool to determine how JEV seropositivity modulate dengue immunity and disease severity when undertaking dengue vaccine trials.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Encefalite Japonesa (Espécie)/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Especificidade de Anticorpos , Criança , Sequência Conservada , Reações Cruzadas , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/classificação , Vírus da Dengue/genética , Vírus da Dengue/imunologia , Vírus da Encefalite Japonesa (Espécie)/genética , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/imunologia , Encefalite Japonesa/virologia , Ensaio de Imunoadsorção Enzimática/estatística & dados numéricos , Feminino , Voluntários Saudáveis , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Sorogrupo , Sri Lanka/epidemiologia , Vacinação , Proteínas Virais/genética , Proteínas Virais/imunologia , Adulto Jovem
2.
PLoS One ; 15(9): e0239584, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966331

RESUMO

Familial forms of Alzheimer's disease (AD) are caused by mutations in the presenilin genes or in the gene encoding for the amyloid precursor protein (APP). Proteolytic cleavage of APP generates the ß-amyloid peptide (Aß), which aggregates into amyloid plaques, one of the major hallmarks of AD. APP mutations within the Aß sequence, so-called intra-Aß mutations, cluster around position E693 of APP, which corresponds to position E22 in the Aß sequence. One of these mutations is the Osaka mutation, E693Δ, which has unique aggregation properties with patients showing unusually low brain amyloid levels on amyloid PET scans. Despite intense research on the pathomechanisms of different intra-Aß mutants, our knowledge is limited due to controversial findings in various studies. Here, we investigated in an ex vivo experimental system the neuro- and synaptotoxic properties of two intra-Aß mutants with different intrinsic aggregation propensities, the Osaka mutation E22Δ and the Arctic mutation E22G, and compared them to wild-type (wt) Aß. Experiments in hippocampal slice cultures from transgenic mice were complemented by treating wild-type slices with recombinantly produced Aß40 or Aß42 containing the respective intra-Aß mutations. Our analyses revealed that wt Aß and E22G Aß, both recombinant and transgenic, caused a loss of dendritic spines along with an increase in tau phosphorylation and tau-dependent neurodegeneration. In all experiments, the 42-residue variants of wt and E22G Aß showed stronger effects than the respective Aß40 isoforms. In contrast, E22Δ Aß neither reduced dendritic spine density nor resulted in increased tau phosphorylation or neuronal cell death in our ex vivo system. Our findings suggest that the previously reported major differences in the aggregation kinetics between E22G and E22Δ Aß are likely reflected in different disease pathomechanisms.


Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/genética , Proteínas Mutantes/genética , Mutação , Proteínas tau/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Animais , Morte Celular , Espinhas Dendríticas/patologia , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Técnicas In Vitro , Cinética , Camundongos , Camundongos Transgênicos , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fosforilação , Agregação Patológica de Proteínas/genética , Agregação Patológica de Proteínas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sinapses/patologia
3.
PLoS Biol ; 18(9): e3000821, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32886672

RESUMO

As a novel alternative to established surface display or combinatorial chemistry approaches for the discovery of therapeutic peptides, we present a method for the isolation of small, cysteine-rich domains from bovine antibody ultralong complementarity-determining regions (CDRs). We show for the first time that isolated bovine antibody knob domains can function as autonomous entities by binding antigen outside the confines of the antibody scaffold. This yields antibody fragments so small as to be considered peptides, each stabilised by an intricate, bespoke arrangement of disulphide bonds. For drug discovery, cow immunisations harness the immune system to generate knob domains with affinities in the picomolar to low nanomolar range, orders of magnitude higher than unoptimized peptides from naïve library screening. Using this approach, knob domain peptides that tightly bound Complement component C5 were obtained, at scale, using conventional antibody discovery and peptide purification techniques.


Assuntos
Anticorpos/química , Dissulfetos/isolamento & purificação , Domínios de Imunoglobulina , Fragmentos de Peptídeos/isolamento & purificação , Domínios e Motivos de Interação entre Proteínas , Animais , Anticorpos/imunologia , Anticorpos/metabolismo , Afinidade de Anticorpos , Formação de Anticorpos , Especificidade de Anticorpos , Antígenos/genética , Antígenos/imunologia , Linfócitos B/fisiologia , Bovinos , Complemento C5/química , Complemento C5/genética , Complemento C5/imunologia , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/imunologia , Dissulfetos/química , Dissulfetos/imunologia , Mapeamento de Epitopos/métodos , Humanos , Imunização , Domínios de Imunoglobulina/genética , Modelos Moleculares , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Domínios e Motivos de Interação entre Proteínas/genética
4.
Acta Odontol Latinoam ; 33(2): 125, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920615

RESUMO

Melatonin (MLT) is a potential signaling molecule in the homeostasis of bone metabolism and may be an important mediator of bone formation and stimulation. The aim of this in vitro study was to evaluate the effect of MLT on the viability, mRNA/protein expression and mineralization of pre-osteoblastic cells. The concentrations 5, 2.5, 1, 0.1 and 0.01 mM MLT were tested on pre-osteoblastic cells (MC3T3) compared to control (no MLT), evaluating proliferation and cell viability (C50), gene expression (RT-PCR) and secretion (ELISA) of COL-I and OPN at 24h, 48h and 72h, and the formation of mineral nodules (alizarin red and fast red) after 10 days of treatment. MLT at 5 and 2.5 mM proved to be cytotoxic (C50), so only 0.01, 0.1 and 1 mM were used for the subsequent analyses. OPN mRNA expression increased with MLT at 0.1 mM - 1 mM, which was followed by increased secretion of OPN both at 24h and 72h compared to the remaining groups (p <0.05). COL-I mRNA and COL-1 secretion followed the same pattern as OPN at 0.1 mM MLT at 72h of treatment (p <0.05). Regarding mineralization, all MLT doses (except 1mM) caused an increase (p <0.05) in the formation of mineral nodules compared to the control. Melatonin at 0.01mM - 1mM had a stimulatory effect on osteoblasts by upregulating COL-I and OPN expression/ secretion and mineralization, thereby fostering osteogenesis.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Metaloproteinase 2 da Matriz/metabolismo , Melatonina/farmacologia , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Osteopontina/metabolismo , Fragmentos de Peptídeos/metabolismo , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Ensaio de Imunoadsorção Enzimática , Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Humanos , Metaloproteinase 2 da Matriz/genética , Osteoblastos/metabolismo , Osteopontina/genética , Fragmentos de Peptídeos/genética , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real
5.
PLoS One ; 15(9): e0238717, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915852

RESUMO

INTRODUCTION: Association between elevated cytokeratin 18 (CK-18) levels and hepatocyte death has made circulating CK-18 a candidate biomarker to differentiate non-alcoholic fatty liver from non-alcoholic steatohepatitis (NASH). Yet studies produced variable diagnostic performance. We aimed to provide summary estimates with increased precision for the accuracy of CK-18 (M30, M65) in detecting NASH and fibrosis among non-alcoholic fatty liver disease (NAFLD) adults. METHODS: We searched five databases to retrieve studies evaluating CK-18 against a liver biopsy in NAFLD adults. Reference screening, data extraction and quality assessment (QUADAS-2) were independently conducted by two authors. Meta-analyses were performed for five groups based on the CK-18 antigens and target conditions, using one of two methods: linear mixed-effects multiple thresholds model or bivariate logit-normal random-effects model. RESULTS: We included 41 studies, with data on 5,815 participants. A wide range of disease prevalence was observed. No study reported a pre-defined cut-off. Thirty of 41 studies provided sufficient data for inclusion in any of the meta-analyses. Summary AUC [95% CI] were: 0.75 [0.69-0.82] (M30) and 0.82 [0.69-0.91] (M65) for NASH; 0.73 [0.57-0.85] (M30) for fibrotic NASH; 0.68 (M30) for significant (F2-4) fibrosis; and 0.75 (M30) for advanced (F3-4) fibrosis. Thirteen studies used CK-18 as a component of a multimarker model. CONCLUSIONS: For M30 we found lower diagnostic accuracy to detect NASH compared to previous meta-analyses, indicating a limited ability to act as a stand-alone test, with better performance for M65. Additional external validation studies are needed to obtain credible estimates of the diagnostic accuracy of multimarker models.


Assuntos
Queratina-18/genética , Cirrose Hepática/diagnóstico , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Fragmentos de Peptídeos/genética , Adulto , Biomarcadores/metabolismo , Biópsia , Morte Celular/genética , Feminino , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia
6.
Proc Natl Acad Sci U S A ; 117(33): 19926-19937, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32732434

RESUMO

The early events in the aggregation of the intrinsically disordered peptide, amyloid-ß (Aß), involve transitions from the disordered free energy ground state to assembly-competent states. Are the fingerprints of order found in the amyloid fibrils encoded in the conformations that the monomers access at equilibrium? If so, could the enhanced aggregation rate of Aß42 compared to Aß40 be rationalized from the sparsely populated high free energy states of the monomers? Here, we answer these questions in the affirmative using coarse-grained simulations of the self-organized polymer-intrinsically disordered protein (SOP-IDP) model of Aß40 and Aß42. Although both the peptides have practically identical ensemble-averaged properties, characteristic of random coils (RCs), the conformational ensembles of the two monomers exhibit sequence-specific heterogeneity. Hierarchical clustering of conformations reveals that both the peptides populate high free energy aggregation-prone ([Formula: see text]) states, which resemble the monomers in the fibril structure. The free energy gap between the ground (RC) and the [Formula: see text] states of Aß42 peptide is smaller than that for Aß40. By relating the populations of excited states of the two peptides to the fibril formation time scales using an empirical formula, we explain nearly quantitatively the faster aggregation rate of Aß42 relative to Aß40. The [Formula: see text] concept accounts for fibril polymorphs, leading to the prediction that the less stable [Formula: see text] state of Aß42, encoding for the U-bend fibril, should form earlier than the structure with the S-bend topology, which is in accord with Ostwald's rule rationalizing crystal polymorph formation.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/química , Fragmentos de Peptídeos/química , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Entropia , Humanos , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Agregados Proteicos
7.
Proc Natl Acad Sci U S A ; 117(25): 14482-14492, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32518112

RESUMO

Cerebral amyloid angiopathy (CAA), where beta-amyloid (Aß) deposits around cerebral blood vessels, is a major contributor of vascular dysfunction in Alzheimer's disease (AD) patients. However, the molecular mechanism underlying CAA formation and CAA-induced cerebrovascular pathology is unclear. Hereditary cerebral amyloid angiopathy (HCAA) is a rare familial form of CAA in which mutations within the (Aß) peptide cause an increase in vascular deposits. Since the interaction between Aß and fibrinogen increases CAA and plays an important role in cerebrovascular damage in AD, we investigated the role of the Aß-fibrinogen interaction in HCAA pathology. Our work revealed the most common forms of HCAA-linked mutations, Dutch (E22Q) and Iowa (D23N), resulted in up to a 50-fold stronger binding affinity of Aß for fibrinogen. In addition, the stronger interaction between fibrinogen and mutant Aßs led to a dramatic perturbation of clot structure and delayed fibrinolysis. Immunofluorescence analysis of the occipital cortex showed an increase of fibrin(ogen)/Aß codeposition, as well as fibrin deposits in HCAA patients, compared to early-onset AD patients and nondemented individuals. Our results suggest the HCAA-type Dutch and Iowa mutations increase the interaction between fibrinogen and Aß, which might be central to cerebrovascular pathologies observed in HCAA.


Assuntos
Peptídeos beta-Amiloides/genética , Encéfalo/patologia , Angiopatia Amiloide Cerebral Familiar/patologia , Fibrina/metabolismo , Fibrinogênio/metabolismo , Fragmentos de Peptídeos/genética , Peptídeos beta-Amiloides/metabolismo , Angiopatia Amiloide Cerebral Familiar/genética , Feminino , Fibrinogênio/isolamento & purificação , Fibrinólise/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Fragmentos de Peptídeos/metabolismo , Ligação Proteica/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo
8.
Rev Med Virol ; 30(5): e2119, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32584474

RESUMO

The novel coronavirus disease 2019 (COVID-19) is rapidly expanding and causing many deaths all over the world with the World Health Organization (WHO) declaring a pandemic in March 2020. Current therapeutic options are limited and there is no registered and/or definite treatment or vaccine for this disease or the causative infection, severe acute respiratory coronavirus 2 syndrome (SARS-CoV-2). Angiotensin-converting enzyme 2 (ACE2), a part of the renin-angiotensin system (RAS), serves as the major entry point into cells for SARS-CoV-2 which attaches to human ACE2, thereby reducing the expression of ACE2 and causing lung injury and pneumonia. Vitamin D, a fat-soluble-vitamin, is a negative endocrine RAS modulator and inhibits renin expression and generation. It can induce ACE2/Ang-(1-7)/MasR axis activity and inhibits renin and the ACE/Ang II/AT1R axis, thereby increasing expression and concentration of ACE2, MasR and Ang-(1-7) and having a potential protective role against acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Therefore, targeting the unbalanced RAS and ACE2 down-regulation with vitamin D in SARS-CoV-2 infection is a potential therapeutic approach to combat COVID-19 and induced ARDS.


Assuntos
Lesão Pulmonar Aguda/prevenção & controle , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Betacoronavirus/patogenicidade , Infecções por Coronavirus/tratamento farmacológico , Peptidil Dipeptidase A/genética , Pneumonia Viral/tratamento farmacológico , Receptores Virais/genética , Vitamina D/uso terapêutico , Lesão Pulmonar Aguda/patologia , Lesão Pulmonar Aguda/virologia , Angiotensina I/genética , Angiotensina I/metabolismo , Betacoronavirus/genética , Betacoronavirus/metabolismo , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Pandemias , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Ligação Proteica , Receptor Tipo 1 de Angiotensina/genética , Receptor Tipo 1 de Angiotensina/metabolismo , Receptores Virais/antagonistas & inibidores , Receptores Virais/metabolismo , Sistema Renina-Angiotensina/efeitos dos fármacos , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
9.
Proc Natl Acad Sci U S A ; 117(22): 12095-12100, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32409607

RESUMO

To advance mechanistic understanding of membrane-associated peptide folding and insertion, we have studied the kinetics of three single tryptophan pHLIP (pH-Low Insertion Peptide) variants, where tryptophan residues are located near the N terminus, near the middle, and near the inserting C-terminal end of the pHLIP transmembrane helix. Single-tryptophan pHLIP variants allowed us to probe different parts of the peptide in the pathways of peptide insertion into the lipid bilayer (triggered by a pH drop) and peptide exit from the bilayer (triggered by a rise in pH). By using pH jumps of different magnitudes, we slowed down the processes and established the intermediates that helped us to understand the principles of insertion and exit. The obtained results should also aid the applications in medicine that are now entering the clinic.


Assuntos
Membrana Celular/metabolismo , Bicamadas Lipídicas/metabolismo , Proteínas de Membrana/metabolismo , Fragmentos de Peptídeos/metabolismo , Membrana Celular/química , Humanos , Concentração de Íons de Hidrogênio , Cinética , Bicamadas Lipídicas/química , Lipossomos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Dobramento de Proteína , Termodinâmica , Triptofano/química , Triptofano/genética
10.
Oncogene ; 39(24): 4770-4779, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32366905

RESUMO

Nuclear protein of the testis (NUT) midline carcinoma (NMC), is a rare and highly aggressive form of undifferentiated squamous cell carcinoma. NMC is molecularly characterized by chromosomal rearrangement of the NUT gene to another gene, most commonly the bromodomain and extraterminal domain (BET) gene BRD4, forming the BRD4-NUT fusion oncogene. Therefore, inhibiting BRD4-NUT oncogenic function directly by BET inhibitors represents an attractive therapeutic approach but toxicity may limit the use of pan-BET inhibitors treating this cancer. We thus performed a drug screening approach using a library consisting of epigenetic compounds and 'Donated Chemical Probes' collated by the Structural Genomics Consortium (SGC) and identified the p300/CBP HAT inhibitor A-485, in addition to the well-known BET inhibitor JQ1, to be the most active candidate for NMC treatment. In contrast to JQ1, A-485 was selectively potent in NMC compared to other cell lines tested. Mechanistically, A-485 inhibited p300-mediated histone acetylation, leading to disruption of BRD4-NUT binding to hyperacetylated megadomains. Consistently, BRD4-NUT megadomain-associated genes MYC, CCAT1 and TP63 were downregulated by A-485. A-485 strongly induced squamous differentiation, cell cycle arrest and apoptosis. Combined inhibition of p300/CBP and BET showed synergistic effects. In summary, we identified the p300/CBP HAT domain as a putative therapeutic target in highly therapy-resistant NMC.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Escamosas , Sistemas de Liberação de Medicamentos , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Fragmentos de Peptídeos , Sialoglicoproteínas , Antineoplásicos/química , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Compostos Heterocíclicos de 4 ou mais Anéis/química , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Domínios Proteicos , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Sialoglicoproteínas/antagonistas & inibidores , Sialoglicoproteínas/genética , Sialoglicoproteínas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
11.
J Biotechnol ; 318: 51-56, 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-32387449

RESUMO

Multiple sclerosis (MS) affects 2.3 million patients worldwide with no effective treatments available thus far. Depletion of autoreactive T-cells is considered the basis for immunotherapeutic approaches. For this purpose the peptides BV5S2, BV6S5, and BV13S1 have been identified as candidates for the development of a MS vaccine. Herein, the plant-based simultaneous production of these peptides is described as an effort to generate a new model of MS immunotherapy. A polyprotein comprising the sequence of the target peptides was designed having the picornaviral 2A sequence in between to mediate the release of the individual peptides upon translation. A codon optimized gene was cloned in vectors mediating constitutive (CaMV35S promoter) or inducible (AlcA promoter) expression. No transgenic tobacco plants were recovered from the constitutive vector suggesting toxicity of the target peptides. In contrast, several transformed lines were obtained with the inducible vector. The individual BV5S2, BV6S5, and BV13S1 peptides were detected in transformed lines upon ethanol-mediated induction and a quantitative analysis based on a OVA conjugate carrying the three peptides revealed accumulation levels up to 0.5 µg g-1 FW leaves. The plant-made peptides were able to induce humoral responses in orally immunized mice. This platform will be useful in the development of alternative immunotherapies against MS having low cost and safety as main attributes. Moreover the platform represents an attractive alternative for the expression of antigens having detrimental effects in plants.


Assuntos
Imunoterapia , Esclerose Múltipla/terapia , Fragmentos de Peptídeos/genética , Plantas Geneticamente Modificadas/genética , Receptores de Antígenos de Linfócitos T/genética , Animais , Cisteína Endopeptidases/genética , Expressão Gênica , Vetores Genéticos , Humanos , Imunização , Camundongos , Esclerose Múltipla/imunologia , Fragmentos de Peptídeos/imunologia , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas/genética , Receptores de Antígenos de Linfócitos T/imunologia , Tabaco/genética , Tabaco/metabolismo , Vacinas de Subunidades/genética , Vacinas de Subunidades/imunologia , Proteínas Virais/genética
12.
PLoS One ; 15(5): e0233700, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469963

RESUMO

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and amyloid-beta (Aß) depositions generated by the proteolysis of amyloid precursor protein (APP) in the brain. In APPNL-F mice, APP gene was humanized and contains two familial AD mutations, and APP-unlike other mouse models of AD-is driven by the endogenous mouse APP promoter. Similar to people without apparent cognitive dysfunction but with heavy Aß plaque load, we found no significant decline in the working memory of adult APPNL-F mice, but these mice showed decline in the expression of normal anxiety. Using immunohistochemistry and 3D block-face scanning electron microscopy, we found no changes in GABAA receptor positivity and size of somatic and dendritic synapses of hippocampal interneurons. We did not find alterations in the level of expression of perineuronal nets around parvalbumin (PV) interneurons or in the density of PV- or somatostatin-positive hippocampal interneurons. However, in contrast to other investigated cell types, PV interneuron axons were occasionally mildly dystrophic around Aß plaques, and the synapses of PV-positive axon initial segment (AIS)-targeting interneurons were significantly enlarged. Our results suggest that PV interneurons are highly resistant to amyloidosis in APPNL-F mice and amyloid-induced increase in hippocampal pyramidal cell excitability may be compensated by PV-positive AIS-targeting cells. Mechanisms that make PV neurons more resilient could therefore be exploited in the treatment of AD for mitigating Aß-related inflammatory effects on neurons.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Hipocampo/metabolismo , Interneurônios/metabolismo , Mutação , Rede Nervosa/metabolismo , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/genética , Animais , Axônios/metabolismo , Axônios/patologia , Hipocampo/patologia , Humanos , Interneurônios/patologia , Memória de Curto Prazo , Camundongos , Camundongos Transgênicos , Rede Nervosa/patologia , Fragmentos de Peptídeos/genética , Células Piramidais/metabolismo , Células Piramidais/patologia , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo
13.
Mol Hum Reprod ; 26(6): 367-373, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32365180

RESUMO

The 2019 novel coronavirus (2019-nCoV) appeared in December 2019 and then spread throughout the world rapidly. The virus invades the target cell by binding to angiotensin-converting enzyme (ACE) 2 and modulates the expression of ACE2 in host cells. ACE2, a pivotal component of the renin-angiotensin system, exerts its physiological functions by modulating the levels of angiotensin II (Ang II) and Ang-(1-7). We reviewed the literature that reported the distribution and function of ACE2 in the female reproductive system, hoping to clarify the potential harm of 2019-nCoV to female fertility. The available evidence suggests that ACE2 is widely expressed in the ovary, uterus, vagina and placenta. Therefore, we believe that apart from droplets and contact transmission, the possibility of mother-to-child and sexual transmission also exists. Ang II, ACE2 and Ang-(1-7) regulate follicle development and ovulation, modulate luteal angiogenesis and degeneration, and also influence the regular changes in endometrial tissue and embryo development. Taking these functions into account, 2019-nCoV may disturb the female reproductive functions through regulating ACE2.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/patologia , Genitália Feminina/virologia , Pandemias , Peptidil Dipeptidase A/genética , Pneumonia Viral/epidemiologia , Pneumonia Viral/patologia , Glicoproteína da Espícula de Coronavírus/genética , Adulto , Angiotensina I/genética , Angiotensina I/metabolismo , Angiotensina II/genética , Angiotensina II/metabolismo , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Feminino , Regulação da Expressão Gênica , Genitália Feminina/patologia , Interações Hospedeiro-Patógeno/genética , Humanos , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/diagnóstico , Pneumonia Viral/transmissão , Gravidez , Ligação Proteica , Receptores Virais/genética , Receptores Virais/metabolismo , Sistema Renina-Angiotensina/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
14.
Nat Commun ; 11(1): 2070, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: covidwho-116533

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, at the end of 2019, and there are currently no specific antiviral treatments or vaccines available. SARS-CoV-2 has been shown to use the same cell entry receptor as SARS-CoV, angiotensin-converting enzyme 2 (ACE2). In this report, we generate a recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. A fusion protein containing an ACE2 mutant with low catalytic activity is also used in this study. The fusion proteins are then characterized. Both fusion proteins have a high binding affinity for the receptor-binding domains of SARS-CoV and SARS-CoV-2 and exhibit desirable pharmacological properties in mice. Moreover, the fusion proteins neutralize virus pseudotyped with SARS-CoV or SARS-CoV-2 spike proteins in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they have potential applications in the diagnosis, prophylaxis, and treatment of SARS-CoV-2.


Assuntos
Betacoronavirus/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/química , Imunoglobulina G/química , Testes de Neutralização , Peptidil Dipeptidase A/química , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/farmacologia , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Animais , Betacoronavirus/metabolismo , Ligação Competitiva/efeitos dos fármacos , Reações Cruzadas , Desenho de Fármacos , Humanos , Fragmentos Fc das Imunoglobulinas/metabolismo , Fragmentos Fc das Imunoglobulinas/farmacologia , Imunoglobulina G/metabolismo , Imunoglobulina G/farmacologia , Técnicas In Vitro , Concentração Inibidora 50 , Fusão de Membrana/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/farmacocinética , Peptidil Dipeptidase A/farmacologia , Domínios Proteicos/genética , Estabilidade Proteica , Receptores Virais/antagonistas & inibidores , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacocinética , Vírus da SARS/efeitos dos fármacos , Vírus da SARS/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
15.
Nat Commun ; 11(1): 2070, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-32332765

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, at the end of 2019, and there are currently no specific antiviral treatments or vaccines available. SARS-CoV-2 has been shown to use the same cell entry receptor as SARS-CoV, angiotensin-converting enzyme 2 (ACE2). In this report, we generate a recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. A fusion protein containing an ACE2 mutant with low catalytic activity is also used in this study. The fusion proteins are then characterized. Both fusion proteins have a high binding affinity for the receptor-binding domains of SARS-CoV and SARS-CoV-2 and exhibit desirable pharmacological properties in mice. Moreover, the fusion proteins neutralize virus pseudotyped with SARS-CoV or SARS-CoV-2 spike proteins in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they have potential applications in the diagnosis, prophylaxis, and treatment of SARS-CoV-2.


Assuntos
Betacoronavirus/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/química , Imunoglobulina G/química , Testes de Neutralização , Peptidil Dipeptidase A/química , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/farmacologia , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Animais , Betacoronavirus/metabolismo , Ligação Competitiva/efeitos dos fármacos , Reações Cruzadas , Desenho de Fármacos , Humanos , Fragmentos Fc das Imunoglobulinas/metabolismo , Fragmentos Fc das Imunoglobulinas/farmacologia , Imunoglobulina G/metabolismo , Imunoglobulina G/farmacologia , Técnicas In Vitro , Concentração Inibidora 50 , Fusão de Membrana/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/farmacocinética , Peptidil Dipeptidase A/farmacologia , Domínios Proteicos/genética , Estabilidade Proteica , Receptores Virais/antagonistas & inibidores , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacocinética , Vírus da SARS/efeitos dos fármacos , Vírus da SARS/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
16.
Proc Natl Acad Sci U S A ; 117(19): 10322-10328, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32345723

RESUMO

Atomistic description of protein fibril formation has been elusive due to the complexity and long time scales of the conformational search. Here, we develop a multiscale approach combining numerous atomistic simulations in explicit solvent to construct Markov State Models (MSMs) of fibril growth. The search for the in-register fully bound fibril state is modeled as a random walk on a rugged two-dimensional energy landscape defined by ß-sheet alignment and hydrogen-bonding states, whereas transitions involving states without hydrogen bonds are derived from kinetic clustering. The reversible association/dissociation of an incoming peptide and overall growth kinetics are then computed from MSM simulations. This approach is applied to derive a parameter-free, comprehensive description of fibril elongation of Aß16-22 and how it is modulated by phenylalanine-to-cyclohexylalanine (CHA) mutations. The trajectories show an aggregation mechanism in which the peptide spends most of its time trapped in misregistered ß-sheet states connected by weakly bound states twith short lifetimes. Our results recapitulate the experimental observation that mutants CHA19 and CHA1920 accelerate fibril elongation but have a relatively minor effect on the critical concentration for fibril growth. Importantly, the kinetic consequences of mutations arise from cumulative effects of perturbing the network of productive and nonproductive pathways of fibril growth. This is consistent with the expectation that nonfunctional states will not have evolved efficient folding pathways and, therefore, will require a random search of configuration space. This study highlights the importance of describing the complete energy landscape when studying the elongation mechanism and kinetics of protein fibrils.


Assuntos
Peptídeos beta-Amiloides/química , Amiloide/química , Mutação , Fragmentos de Peptídeos/química , Fenilalanina/análogos & derivados , Fenilalanina/genética , Peptídeos beta-Amiloides/genética , Simulação por Computador , Humanos , Ligação de Hidrogênio , Cinética , Modelos Moleculares , Fragmentos de Peptídeos/genética , Estrutura Secundária de Proteína , Termodinâmica
17.
Artigo em Inglês | MEDLINE | ID: mdl-32320286

RESUMO

To date, studies that have aimed to investigate the role of satellite cells during adult skeletal muscle adaptation and hypertrophy have utilized a nontranslational stimulus and/or have been performed over a relatively short time frame. Although it has been shown that satellite cell depletion throughout adulthood does not drive skeletal muscle loss in sedentary mice, it remains unknown how satellite cells participate in skeletal muscle adaptation to long-term physical activity. The current study was designed to determine whether reduced satellite cell content throughout adulthood would influence the transcriptome-wide response to physical activity and diminish the adaptive response of skeletal muscle. We administered vehicle or tamoxifen to adult Pax7-diphtheria toxin A (DTA) mice to deplete satellite cells and assigned them to sedentary or wheel-running conditions for 13 mo. Satellite cell depletion throughout adulthood reduced balance and coordination, overall running volume, and the size of muscle proprioceptors (spindle fibers). Furthermore, satellite cell participation was necessary for optimal muscle fiber hypertrophy but not adaptations in fiber type distribution in response to lifelong physical activity. Transcriptome-wide analysis of the plantaris and soleus revealed that satellite cell function is muscle type specific; satellite cell-dependent myonuclear accretion was apparent in oxidative muscles, whereas initiation of G protein-coupled receptor (GPCR) signaling in the glycolytic plantaris may require satellite cells to induce optimal adaptations to long-term physical activity. These findings suggest that satellite cells play a role in preserving physical function during aging and influence muscle adaptation during sustained periods of physical activity.


Assuntos
Fibras Musculares Esqueléticas/patologia , Condicionamento Físico Animal , Corrida , Células Satélites de Músculo Esquelético/patologia , Comportamento Sedentário , Adaptação Fisiológica , Animais , Toxina Diftérica/genética , Feminino , Regulação da Expressão Gênica , Glicólise , Hipertrofia , Camundongos Transgênicos , Fibras Musculares Esqueléticas/metabolismo , Oxirredução , Fator de Transcrição PAX7/genética , Fragmentos de Peptídeos/genética , RNA não Traduzido/genética , Células Satélites de Músculo Esquelético/metabolismo , Fatores de Tempo
18.
Proc Natl Acad Sci U S A ; 117(19): 10286-10293, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32341150

RESUMO

HIV-1 maturation involves conversion of the immature Gag polyprotein lattice, which lines the inner surface of the viral membrane, to the mature capsid protein (CA) lattice, which encloses the viral RNA. Maturation inhibitors such as bevirimat (BVM) bind within six-helix bundles, formed by a segment that spans the junction between the CA and spacer peptide 1 (SP1) subunits of Gag, and interfere with cleavage between CA and SP1 catalyzed by the HIV-1 protease (PR). We report solid-state NMR (ssNMR) measurements on spherical virus-like particles (VLPs), facilitated by segmental isotopic labeling, that provide information about effects of BVM on the structure and dynamics of CA-SP1 junction helices in the immature lattice. Although BVM strongly blocks PR-catalyzed CA-SP1 cleavage in VLPs and blocks conversion of VLPs to tubular CA assemblies, 15N and 13C ssNMR chemical shifts of segmentally labeled VLPs with and without BVM are very similar, indicating that interaction with BVM does not alter the six-helix bundle structure appreciably. Only the 15N chemical shift of A280 (the first residue of SP1) changes significantly, consistent with BVM binding to an internal ring of hydrophobic side chains of L279 residues. Measurements of transverse 15N spin relaxation rates reveal a reduction in the amplitudes and/or timescales of backbone N-H bond motions, corresponding to a rigidification of the six-helix bundles. Overall, our data show that inhibition of HIV-1 maturation by BVM involves changes in structure and dynamics that are surprisingly subtle, but still sufficient to produce a large effect on CA-SP1 cleavage.


Assuntos
Proteínas do Capsídeo/química , HIV-1/efeitos dos fármacos , Fragmentos de Peptídeos/química , Succinatos/farmacologia , Triterpenos/farmacologia , Vírion/efeitos dos fármacos , Replicação Viral , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismo , Fármacos Anti-HIV/farmacologia , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Farmacorresistência Viral , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , Infecções por HIV/virologia , HIV-1/genética , HIV-1/metabolismo , Humanos , Modelos Moleculares , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Conformação Proteica , Vírion/genética , Vírion/metabolismo , Montagem de Vírus , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética
19.
Nat Commun ; 11(1): 1377, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32170138

RESUMO

The relationship between amyloid-ß (Aß) species and tau pathology in Alzheimer's disease (AD) is not fully understood. Here, we provide direct evidence that Aß42/40 ratio, not total Aß level, plays a critical role in inducing neurofibrillary tangles (NTFs) in human neurons. Using 3D-differentiated clonal human neural progenitor cells (hNPCs) expressing varying levels of amyloid ß precursor protein (APP) and presenilin 1 (PS1) with AD mutations, we show that pathogenic tau accumulation and aggregation are tightly correlated with Aß42/40 ratio. Roles of Aß42/40 ratio on tau pathology are also confirmed with APP transmembrane domain (TMD) mutant hNPCs, which display differential Aß42/40 ratios without mutant PS1. Moreover, naïve hNPCs co-cultured with APP TMD I45F (high Aß42/40) cells, not with I47F cells (low Aß42/40), develop robust tau pathology in a 3D non-cell autonomous cell culture system. These results emphasize the importance of reducing the Aß42/40 ratio in AD therapy.


Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Técnicas de Cultura de Células/métodos , Neurônios/metabolismo , Neurônios/patologia , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/genética , Células Cultivadas , Técnicas de Cocultura , Humanos , Mutação , Células-Tronco Neurais/metabolismo , Fragmentos de Peptídeos/genética , Presenilina-1/genética , Presenilina-1/metabolismo
20.
Diabetes ; 69(4): 559-566, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32198197

RESUMO

Genetic studies of patients with neonatal progeroid syndrome led to the discovery of the novel fasting-induced, glucogenic, and orexigenic hormone named asprosin, the C-terminal cleavage product of profibrillin. Upon secretion, asprosin travels to the liver, where it exerts a glucogenic effect through OR4M1, an olfactory G-protein-coupled receptor. It also crosses the blood-brain barrier to stimulate appetite-modulating neurons in the arcuate nucleus of the hypothalamus, exerting an orexigenic effect via an as yet unidentified receptor. Specifically, it stimulates appetite by activating orexigenic AgRP neurons and inhibiting anorexigenic POMC neurons. Studies have also focused on the therapeutic potential of inhibiting asprosin for treatment of obesity and type 2 diabetes, both of which are characterized by high levels of circulating asprosin. It has been shown that anti-asprosin monoclonal antibodies reduce blood glucose, appetite, and body weight, validating asprosin as a therapeutic target. Current work aims to uncover key features of the asprosin biology such as the identification of its neuronal receptor, identification of the secretion mechanism from adipose tissue, and development of anti-asprosin monoclonal antibodies as diabetes and obesity therapies.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Metabolismo Energético/fisiologia , Proteínas dos Microfilamentos/metabolismo , Obesidade/terapia , Fragmentos de Peptídeos/metabolismo , Hormônios Peptídicos/metabolismo , Animais , Glicemia , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Proteínas dos Microfilamentos/genética , Obesidade/metabolismo , Fragmentos de Peptídeos/genética , Hormônios Peptídicos/genética
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