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1.
Nucleic Acids Res ; 52(11): 6647-6661, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38587193

RESUMO

The viral genome of SARS-CoV-2 is packaged by the nucleocapsid (N-)protein into ribonucleoprotein particles (RNPs), 38 ± 10 of which are contained in each virion. Their architecture has remained unclear due to the pleomorphism of RNPs, the high flexibility of N-protein intrinsically disordered regions, and highly multivalent interactions between viral RNA and N-protein binding sites in both N-terminal (NTD) and C-terminal domain (CTD). Here we explore critical interaction motifs of RNPs by applying a combination of biophysical techniques to ancestral and mutant proteins binding different nucleic acids in an in vitro assay for RNP formation, and by examining nucleocapsid protein variants in a viral assembly assay. We find that nucleic acid-bound N-protein dimers oligomerize via a recently described protein-protein interface presented by a transient helix in its long disordered linker region between NTD and CTD. The resulting hexameric complexes are stabilized by multivalent protein-nucleic acid interactions that establish crosslinks between dimeric subunits. Assemblies are stabilized by the dimeric CTD of N-protein offering more than one binding site for stem-loop RNA. Our study suggests a model for RNP assembly where N-protein scaffolding at high density on viral RNA is followed by cooperative multimerization through protein-protein interactions in the disordered linker.


Assuntos
Proteínas do Nucleocapsídeo de Coronavírus , Multimerização Proteica , RNA Viral , SARS-CoV-2 , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , SARS-CoV-2/química , Proteínas do Nucleocapsídeo de Coronavírus/química , Proteínas do Nucleocapsídeo de Coronavírus/metabolismo , Proteínas do Nucleocapsídeo de Coronavírus/genética , RNA Viral/metabolismo , RNA Viral/química , RNA Viral/genética , Ligação Proteica , Sítios de Ligação , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/genética , Montagem de Vírus/genética , Humanos , Proteínas do Nucleocapsídeo/química , Proteínas do Nucleocapsídeo/metabolismo , Proteínas do Nucleocapsídeo/genética , Modelos Moleculares , Fosfoproteínas/química , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , COVID-19/virologia
2.
Mol Ther ; 32(6): 1721-1738, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38566414

RESUMO

Recombinant adeno-associated viruses (AAVs) allow rapid and efficient gene delivery to the nervous system, are widely used in neuroscience research, and are the basis of FDA-approved neuron-targeting gene therapies. Here we find that an innate immune response to the AAV genome reduces dendritic length and complexity and disrupts synaptic transmission in mouse somatosensory cortex. Dendritic loss is apparent 3 weeks after injection of experimentally relevant viral titers, is not restricted to a particular capsid serotype, transgene, promoter, or production facility, and cannot be explained by responses to surgery or transgene expression. AAV-associated dendritic loss is accompanied by a decrease in the frequency and amplitude of miniature excitatory postsynaptic currents and an increase in the proportion of GluA2-lacking, calcium-permeable AMPA receptors. The AAV genome is rich in unmethylated CpG DNA, which is recognized by the innate immunoreceptor Toll-like receptor 9 (TLR9), and acutely blocking TLR9 preserves dendritic complexity and AMPA receptor subunit composition in AAV-injected mice. These results reveal unexpected impacts of an immune response to the AAV genome on neuronal structure and function and identify approaches to improve the safety and efficacy of AAV-mediated gene delivery in the nervous system.


Assuntos
Dendritos , Dependovirus , Vetores Genéticos , Imunidade Inata , Transmissão Sináptica , Receptor Toll-Like 9 , Animais , Dependovirus/genética , Camundongos , Dendritos/metabolismo , Receptor Toll-Like 9/metabolismo , Receptor Toll-Like 9/genética , Vetores Genéticos/genética , Vetores Genéticos/administração & dosagem , Receptores de AMPA/genética , Receptores de AMPA/metabolismo , Córtex Somatossensorial/metabolismo , Córtex Somatossensorial/imunologia , Genoma Viral
3.
Clin Immunol ; 265: 110304, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38964633

RESUMO

Cladribine (Mavenclad®) is an oral treatment for relapsing remitting MS (RRMS), but its mechanism of action and its effects on innate immune responses in unknown. This study is a prospective Phase IV study of 41 patients with RRMS, and aims to investigate the mechanism of action of cladribine on peripheral monocytes, and its impact on the P2X7 receptor. There was a significant reduction in monocyte count in vivo at week 1 post cladribine administration, and the subset of cells being most impacted were the CD14lo CD16+ 'non-classical' monocytes. Of the 14 cytokines measured in serum, CCL2 levels increased at week 1. In vitro, cladrabine induced a reduction in P2X7R pore as well as channel activity. This study demonstrates a novel mechanism of action for cladribine. It calls for studying potential benefits of cladribine in progressive forms of MS and other neurodegenerative diseases where innate immune related inflammation is implicated in disease pathogenesis.


Assuntos
Cladribina , Citocinas , Imunidade Inata , Monócitos , Esclerose Múltipla Recidivante-Remitente , Humanos , Cladribina/uso terapêutico , Cladribina/farmacologia , Imunidade Inata/efeitos dos fármacos , Feminino , Masculino , Adulto , Estudos Prospectivos , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Esclerose Múltipla Recidivante-Remitente/imunologia , Esclerose Múltipla Recidivante-Remitente/sangue , Monócitos/imunologia , Monócitos/efeitos dos fármacos , Pessoa de Meia-Idade , Citocinas/sangue , Citocinas/imunologia , Receptores Purinérgicos P2X7/imunologia , Imunossupressores/uso terapêutico , Imunossupressores/farmacologia , Adulto Jovem
4.
Artigo em Inglês | MEDLINE | ID: mdl-38710493

RESUMO

INTRODUCTION: Paediatric granulomatous uveitis (PGU) is rare. In addition, lack of awareness often leads to delayed diagnosis and poor visual outcome. Identifying the underlying cause and deciding how best to treat each patient is challenging. OBJECTIVES: To evaluate the demographics, aetiologies, complications, treatments, and visual prognosis of paediatric non-infectious granulomatous uveitis. METHODS: Retrospective chart review of non-infectious PGU occurring in children before the age of 16 years recruited from the Paediatric Rheumatology Unit, Bicêtre Hospital, France, from 2001 to 2023. RESULTS: We included 50 patients with 90 affected eyes: 29 with idiopathic uveitis, 15 with sarcoidosis, 5 with juvenile idiopathic arthritis, and one with Vogt-Koyanagi-Harada disease. Median age at diagnosis was 9.8 years (range 7.2-12.5). The sex-ratio M/F was 0.52. The most common features of PGU were: panuveitis (56%), bilateral (84%), and chronic (84%). Sarcoidosis was the most frequent diagnosis after idiopathic disease, particularly in the presence of lymphopenia and hypergammaglobulinemia. Uveomeningitis was present in 12% of cases. Upon diagnosis, ocular complications were present in 68 of 90 eyes (76%) particularly in cases of panuveitis. The most commonly used treatments were systemic corticosteroids (72%) and methotrexate (80%). Twenty-three percent of eyes were in remission at last follow-up, 68% were inactive and 4% remained active. The median duration of follow-up was 5.8 years. CONCLUSION: We report the largest cohort of PGU. PGU were mostly idiopathic and had a high rate of complications. Sarcoid and idiopathic panuveitis are serious illnesses in which disease-modifying therapy should be initiated at diagnosis to improve management.

5.
J Neurol Neurosurg Psychiatry ; 94(9): 707-717, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37068931

RESUMO

BACKGROUND: Some studies comparing primary and secondary progressive multiple sclerosis (PPMS, SPMS) report similar ages at onset of the progressive phase and similar rates of subsequent disability accrual. Others report later onset and/or faster accrual in SPMS. Comparisons have been complicated by regional cohort effects, phenotypic differences in sex ratio and management and variable diagnostic criteria for SPMS. METHODS: We compared disability accrual in PPMS and operationally diagnosed SPMS in the international, clinic-based MSBase cohort. Inclusion required PPMS or SPMS with onset at age ≥18 years since 1995. We estimated Andersen-Gill hazard ratios for disability accrual on the Expanded Disability Status Scale (EDSS), adjusted for sex, age, baseline disability, EDSS score frequency and drug therapies, with centre and patient as random effects. We also estimated ages at onset of the progressive phase (Kaplan-Meier) and at EDSS milestones (Turnbull). Analyses were replicated with physician-diagnosed SPMS. RESULTS: Included patients comprised 1872 with PPMS (47% men; 50% with activity) and 2575 with SPMS (32% men; 40% with activity). Relative to PPMS, SPMS had older age at onset of the progressive phase (median 46.7 years (95% CI 46.2-47.3) vs 43.9 (43.3-44.4); p<0.001), greater baseline disability, slower disability accrual (HR 0.86 (0.78-0.94); p<0.001) and similar age at wheelchair dependence. CONCLUSIONS: We demonstrate later onset of the progressive phase and slower disability accrual in SPMS versus PPMS. This may balance greater baseline disability in SPMS, yielding convergent disability trajectories across phenotypes. The different rates of disability accrual should be considered before amalgamating PPMS and SPMS in clinical trials.


Assuntos
Pessoas com Deficiência , Esclerose Múltipla Crônica Progressiva , Esclerose Múltipla , Humanos , Esclerose Múltipla Crônica Progressiva/tratamento farmacológico , Progressão da Doença , Modelos de Riscos Proporcionais
6.
Anal Bioanal Chem ; 415(7): 1299-1304, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36459168

RESUMO

Mitochondrial content has been reported outside of cells either within extracellular vesicles (EVs) or as free mitochondria. Mitochondrial EVs can potentially play multiple physiological and pathophysiological roles. To understand their functions, isolation protocols to separate mitochondrial EVs from other mitochondrial content need to be established. In the present work, we use a multiple reaction monitoring assay with isotope labeled internal standards to quantify 11 mitochondrial, 6 plasma membrane-specific, 4 endosomal membrane-specific, and 2 soluble proteins to evaluate the efficiency of chromatographic isolation of mitochondrial EVs. The isolation protocol includes ultracentrifugation, size exclusion chromatography, and chromatography on immobilized heparin. All protein concentrations were normalized to the concentration of ATP synthase alpha subunit to generate a ratio that allows comparison of different samples obtained during the isolation. We have shown that initial samples after ultracentrifugation are contaminated with non-EV mitochondrial content that cannot be separated from EVs using size exclusion chromatography, but can be efficiently separated from EVs on the column with immobilized heparin.


Assuntos
Vesículas Extracelulares , Vesículas Extracelulares/química , Cromatografia em Gel , Mitocôndrias , Heparina/análise , Ultracentrifugação
7.
Proc Natl Acad Sci U S A ; 117(42): 26226-26236, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33028677

RESUMO

VCP/p97, an enzyme critical to proteostasis, is regulated through interactions with protein adaptors targeting it to specific cellular tasks. One such adaptor, p47, forms a complex with p97 to direct lipid membrane remodeling. Here, we use NMR and other biophysical methods to study the structural dynamics of p47 and p47-p97 complexes. Disordered regions in p47 are shown to be critical in directing intra-p47 and p47-p97 interactions via a pair of previously unidentified linear motifs. One of these, an SHP domain, regulates p47 binding to p97 in a manner that depends on the nucleotide state of p97. NMR and electron cryomicroscopy data have been used as restraints in molecular dynamics trajectories to develop structural ensembles for p47-p97 complexes in adenosine diphosphate (ADP)- and adenosine triphosphate (ATP)-bound conformations, highlighting differences in interactions in the two states. Our study establishes the importance of intrinsically disordered regions in p47 for the formation of functional p47-p97 complexes.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Difosfato de Adenosina/metabolismo , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Adenosina Trifosfatases/química , Motivos de Aminoácidos , Humanos , Proteínas Intrinsicamente Desordenadas/química , Modelos Moleculares , Proteínas Nucleares/química , Ligação Proteica , Conformação Proteica
8.
Eur Biophys J ; 50(3-4): 353-362, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33398460

RESUMO

Analytical ultracentrifugation (AUC) is based on the concept of recording and analyzing macroscopic macromolecular redistribution that results from a centrifugal force acting on the mass of suspended macromolecules in solution. Since AUC rests on first principles, it can provide an absolute measurement of macromolecular mass, sedimentation and diffusion coefficients, and many other quantities, provided that the solvent density and viscosity are known, and provided that the instrument is properly calibrated. Unfortunately, a large benchmark study revealed that many instruments exhibit very significant systematic errors. This includes the magnification of the optical detection system used to determine migration distance, the measurement of sedimentation time, and the measurement of the solution temperature governing viscosity. We have previously developed reference materials, tools, and protocols to detect and correct for systematic measurement errors in the AUC by comparison with independently calibrated standards. This 'external calibration' resulted in greatly improved precision and consistency of parameters across laboratories. Here we detail the steps required for calibration of the different data dimensions in the AUC. We demonstrate the calibration of three different instruments with absorbance and interference optical detection, and use measurements of the sedimentation coefficient of NISTmAb monomer as a test of consistency. Whereas the measured uncorrected sedimentation coefficients span a wide range from 6.22 to 6.61 S, proper calibration resulted in a tenfold reduced standard deviation of sedimentation coefficients. The calibrated relative standard deviation and mean error of 0.2% and 0.07%, respectively, is comparable with statistical errors and side-by-side repeatability in a single instrument.


Assuntos
Ultracentrifugação , Calibragem , Substâncias Macromoleculares , Solventes , Viscosidade
9.
Langmuir ; 36(16): 4439-4446, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32293894

RESUMO

This work presents a new method for the synthesis of antifouling polymer brushes using surface-initiated photoinduced electron transfer-reversible addition-fragmentation chain-transfer polymerization with eosin Y and triethanolamine as catalysts. This method proceeds in an aqueous environment under atmospheric conditions without any prior degassing and without the use of heavy metal catalysts. The versatility of the method is shown by using three chemically different monomers: oligo(ethylene glycol) methacrylate, N-(2-hydroxypropyl)methacrylamide, and carboxybetaine methacrylamide. In addition, the light-triggered nature of the polymerization allows the creation of complex three-dimensional structures. The composition and topological structuring of the brushes are confirmed by X-ray photoelectron spectroscopy and atomic force microscopy. The kinetics of the polymerizations are followed by measuring the layer thickness with ellipsometry. The polymer brushes demonstrate excellent antifouling properties when exposed to single-protein solutions and complex biological matrices such as diluted bovine serum. This method thus presents a new simple approach for the manufacturing of antifouling coatings for biomedical and biotechnological applications.

10.
J Neuroophthalmol ; 40(1): 37-43, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32045393

RESUMO

BACKGROUND: Patients with multiple sclerosis (MS) experience progressive thinning in optical coherence tomography (OCT) measures of neuroaxonal structure regardless of optic neuritis history. Few prospective studies have investigated the effects of disease-modifying therapies on neuroaxonal degeneration in the retina. Alemtuzumab is a monoclonal antibody shown to be superior to interferon ß-1a in treating relapsing-remitting MS (RRMS). The purpose of this study was to assess the effects of alemtuzumab and first-line injectable treatments on OCT measures of neuroaxonal structure including peripapillary retinal nerve fiber layer (RNFL) thickness and combined ganglion cell-inner plexiform (GCIP) layer volume in RRMS patients followed up over 5 years. METHODS: In this retrospective pilot study with prospectively collected double cohort data, spectral domain OCT measures of RNFL thickness and GCIP volume were compared between alemtuzumab-treated RRMS patients (N = 24) and RRMS patients treated with either interferon-ß or glatiramer acetate (N = 21). RESULTS: Over a median of 60 months (range 42-60 months), the alemtuzumab cohort demonstrated a change in the mean RNFL thickness (thinning from baseline) of -0.88 µm (95% confidence interval [CI] -2.63 to 0.86; P = 0.32) and mean GCIP volume of +0.013 mm (95% CI -0.006 to 0.032; P = 0.18). Over the same time period, the first-line therapy-treated cohort demonstrated greater degrees of RNFL thinning (mean change in RNFL thickness was -3.65 µm [95% CI -5.40 to -1.89; P = 0.0001]). There was also more prominent GCIP volume loss relative to baseline in the first-line therapy group (-0.052 mm [95% CI -0.070 to -0.034; P < 0.0001]). CONCLUSIONS: Alemtuzumab-treated patients with RRMS demonstrated relative stability of OCT-measured neuroaxonal structure compared with RRMS patients treated with either interferon-ß or glatiramer acetate over a 5-year period. These findings, along with previous demonstration of improved brain atrophy rates, suggest that alemtuzumab may offer long-term preservation of neuroaxonal structure in patients with RRMS.


Assuntos
Alemtuzumab/uso terapêutico , Axônios/patologia , Imunossupressores/uso terapêutico , Esclerose Múltipla Recidivante-Remitente/patologia , Retina/patologia , Neurônios Retinianos/patologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Retina/diagnóstico por imagem , Estudos Retrospectivos , Tomografia de Coerência Óptica , Adulto Jovem
11.
Anal Biochem ; 582: 113354, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31276652

RESUMO

In the last decade, filamentous M13 bacteriophage has emerged into numerous biotechnological applications as a promising nontoxic and self-assembling biomaterial with specific binding properties. This raises a question about its upscale production that consequently requires an accurate phage enumeration during the various protocol developments. However, traditional methods of measuring phage concentration are mainly biological in nature and therefore time and labor intensive. These traditional methods also demonstrate poor reproducibility and are semi-quantitative at best. In the present work, we capitalized on mass spectrometry based absolute protein quantitation. We have optimized the quantitation conditions for a major coat protein, pVIII. Enumeration of M13 bacteriophage can be further performed using the determined molar concentration of pVIII, Avogadro's number, and known copy number of pVIII per phage. Since many different phages have well-defined copy number of capsid proteins, the proposed approach can be simply applied to any phage with known copy number of a specific capsid protein.


Assuntos
Bacteriófago M13/isolamento & purificação , Proteínas do Capsídeo/análise , Espectrometria de Massas/métodos
12.
Med J Aust ; 211(5): 230-236, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30919466

RESUMO

Multiple sclerosis is more prevalent in women of childbearing age than in any other group. As a result, the impact of multiple sclerosis and its treatment on fertility, planned and unplanned pregnancies, post partum care and breastfeeding presents unique challenges that need to be addressed in everyday clinical practice. Given the increasing number of disease-modifying agents now available in Australia for the treatment of multiple sclerosis, there is a growing need for clinicians to provide their patients with appropriate counselling on family planning. Providing better evidence regarding the relative risks and benefits of continuing therapy before, during and after pregnancy is an important research priority. International pregnancy registries are essential in developing better evidence-based practice guidelines, and neurologists should be encouraged to contribute to these when possible. The management of women with multiple sclerosis, especially when they are taking disease-modifying agents, requires careful assessment of fertility and disease characteristics as well as a multidisciplinary approach to ensure positive outcomes in both mothers and their children.


Assuntos
Aconselhamento , Serviços de Planejamento Familiar , Esclerose Múltipla/tratamento farmacológico , Austrália , Aleitamento Materno , Anticoncepção , Feminino , Humanos , Gravidez
13.
Proc Biol Sci ; 284(1863)2017 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-28954903

RESUMO

Seasonal two-way migration is an ecological phenomenon observed in a wide range of large-bodied placental mammals, but is conspicuously absent in all modern marsupials. Most extant marsupials are typically smaller in body size in comparison to their migratory placental cousins, possibly limiting their potential to undertake long-distance seasonal migrations. But what about earlier, now-extinct giant marsupial megafauna? Here we present new geochemical analyses which show that the largest of the extinct marsupial herbivores, the enormous wombat-like Diprotodon optatum, undertook seasonal, two-way latitudinal migration in eastern Sahul (Pleistocene Australia-New Guinea). Our data infer that this giant marsupial had the potential to perform round-trip journeys of as much as 200 km annually, which is reminiscent of modern East African mammal migrations. These findings provide, to our knowledge, the first evidence for repetitive seasonal migration in any metatherian (including marsupials), living or extinct, and point to an ecological phenomenon absent from the continent since the Late Pleistocene.


Assuntos
Migração Animal , Marsupiais , Estações do Ano , Animais , Austrália , Fósseis , Nova Guiné
15.
Paediatr Drugs ; 26(1): 31-47, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37792254

RESUMO

Uveitis in children accounts for 5-10% of all cases. The causes vary considerably. Classically, uveitis is distinguished according to its infectious or inflammatory origin and whether it is part of a systemic disease or represents an isolated ocular disease. It is important to highlight the specificity of certain etiologies among children such as juvenile idiopathic arthritis. The development of visual function can potentially be hindered by amblyopia (children aged < 7 years), in addition to the usual complications (synechiae, macular edema) seen in adult patients. Moreover, the presentation of uveitis in children is often "silent" with few warning signs and few functional complaints from young children, which frequently leads to a substantial diagnostic delay. The diagnostic approach is guided by the presentation of the uveitis, which can be characterized by its location, and corresponds to the initial and main site of intraocular inflammation; its presentation, whether acute or chronic, granulomatous or not; and the response to treatment. Pediatricians have an important role to play and must be aware of the various presentations and etiologies of uveitis in children. Juvenile idiopathic arthritis is the most common etiology of pediatric non-infectious uveitis, but other causes must be recognized. Promptly initiated treatment before complications arise requires early diagnosis, recognition, and treatment. Any dependence on prolonged local corticosteroid therapy justifies discussing the introduction of a corticosteroid-sparing treatment considering the risk to develop corticoid-induced glaucoma and cataracts. Systemic corticosteroid therapy can be required for urgent control of inflammation in the case of severe uveitis. Long-lasting immunosuppressive treatment and biotherapies are most often prescribed at the same time to reinforce treatment efficacy and to prevent relapse and corticosteroid dependency. We review the different causes of uveitis, excluding infection, and the diagnostic and therapeutic management aimed at limiting the risk of irreversible sequelae.


Assuntos
Artrite Juvenil , Uveíte , Criança , Pré-Escolar , Humanos , Corticosteroides/uso terapêutico , Artrite Juvenil/complicações , Artrite Juvenil/diagnóstico , Artrite Juvenil/tratamento farmacológico , Diagnóstico Tardio , Inflamação/complicações , Uveíte/diagnóstico , Uveíte/tratamento farmacológico , Uveíte/etiologia
16.
bioRxiv ; 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38045241

RESUMO

Genetic diversity is a hallmark of RNA viruses and the basis for their evolutionary success. Taking advantage of the uniquely large genomic database of SARS-CoV-2, we examine the impact of mutations across the spectrum of viable amino acid sequences on the biophysical phenotypes of the highly expressed and multifunctional nucleocapsid protein. We find variation in the physicochemical parameters of its extended intrinsically disordered regions (IDRs) sufficient to allow local plasticity, but also exhibiting functional constraints that similarly occur in related coronaviruses. In biophysical experiments with several N-protein species carrying mutations associated with major variants, we find that point mutations in the IDRs can have nonlocal impact and modulate thermodynamic stability, secondary structure, protein oligomeric state, particle formation, and liquid-liquid phase separation. In the Omicron variant, distant mutations in different IDRs have compensatory effects in shifting a delicate balance of interactions controlling protein assembly properties, and include the creation of a new protein-protein interaction interface in the N-terminal IDR through the defining P13L mutation. A picture emerges where genetic diversity is accompanied by significant variation in biophysical characteristics of functional N-protein species, in particular in the IDRs.

17.
Elife ; 132024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38941236

RESUMO

Genetic diversity is a hallmark of RNA viruses and the basis for their evolutionary success. Taking advantage of the uniquely large genomic database of SARS-CoV-2, we examine the impact of mutations across the spectrum of viable amino acid sequences on the biophysical phenotypes of the highly expressed and multifunctional nucleocapsid protein. We find variation in the physicochemical parameters of its extended intrinsically disordered regions (IDRs) sufficient to allow local plasticity, but also observe functional constraints that similarly occur in related coronaviruses. In biophysical experiments with several N-protein species carrying mutations associated with major variants, we find that point mutations in the IDRs can have nonlocal impact and modulate thermodynamic stability, secondary structure, protein oligomeric state, particle formation, and liquid-liquid phase separation. In the Omicron variant, distant mutations in different IDRs have compensatory effects in shifting a delicate balance of interactions controlling protein assembly properties, and include the creation of a new protein-protein interaction interface in the N-terminal IDR through the defining P13L mutation. A picture emerges where genetic diversity is accompanied by significant variation in biophysical characteristics of functional N-protein species, in particular in the IDRs.


Like other types of RNA viruses, the genetic material of SARS-CoV-2 (the agent responsible for COVID-19) is formed of an RNA molecule which is prone to accumulating mutations. This gives SARS-CoV-2 the ability to evolve quickly, and often to remain one step ahead of treatments. Understanding how these mutations shape the behavior of RNA viruses is therefore crucial to keep diseases such as COVID-19 under control. The gene that codes for the protein that 'packages' the genetic information inside SARS-CoV-2 is particularly prone to mutations. This nucleocapsid (N) protein participates in many key processes during the life cycle of the virus, including potentially interfering with the immune response. Exactly how the physical properties of the N-Protein are impacted by the mutations in its genetic sequence remains unclear. To investigate this question, Nguyen et al. predicted the various biophysical properties of different regions of the N-protein based on a computer-based analysis of SARS-CoV-2 genetic databases. This allowed them to determine if specific protein regions were positively or negatively charged in different mutants. The analyses showed that some domains exhibited great variability in their charge between protein variants ­ reflecting the fact that the corresponding genetic sequences showed high levels of plasticity. Other regions remained conserved, however, including across related coronaviruses. Nguyen et al. also conducted biochemical experiments on a range of N-proteins obtained from clinically relevant SARS-CoV-2 variants. Their results highlighted the importance of protein segments with no fixed three-dimensional structure. Mutations in the related sequences created high levels of variation in the physical properties of these 'intrinsically disordered' regions, which had wide-ranging consequences. Some of these genetic changes even gave individual N-proteins the ability to interact with each other in a completely new way. These results shed new light on the relationship between genetic mutations and the variable physical properties of RNA virus proteins. Nguyen et al. hope that this knowledge will eventually help to develop more effective treatments for viral infections.


Assuntos
Proteínas do Nucleocapsídeo de Coronavírus , Mutação , SARS-CoV-2 , SARS-CoV-2/genética , SARS-CoV-2/química , SARS-CoV-2/metabolismo , Proteínas do Nucleocapsídeo de Coronavírus/genética , Proteínas do Nucleocapsídeo de Coronavírus/química , Proteínas do Nucleocapsídeo de Coronavírus/metabolismo , COVID-19/virologia , COVID-19/genética , Humanos , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Fosfoproteínas/química , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Proteínas do Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/metabolismo , Proteínas do Nucleocapsídeo/química , Termodinâmica , Estabilidade Proteica
18.
Medicine (Baltimore) ; 103(28): e38648, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38996094

RESUMO

Gestational diabetes mellitus (GDM) is a common condition during pregnancy and is associated with an increased risk of pre-eclampsia. The methylenetetrahydrofolate reductase (MTHFR) gene plays a crucial role in folate metabolism and has been implicated in GDM. To investigate the relationship between the MTHFR C677T gene polymorphism and the conditions of GDM and gestational prediabetes in pregnant women. A case-control study was conducted in 114 pregnant women with GDM and 96 pregnant women without GDM, from the first trimester to the prenatal examination at Can Tho Obstetrics Hospital. The pregnant women underwent a 1-hour (G1) and 2-hour (G2) oral glucose tolerance test (OGTT) and genetic polymorphism analysis based on real-time PCR technique. In pregnant women with GDM, weight, concentrations of G0, G1, G2, and folic acid were higher than those in the non-GDM group, with P < .05. When analyzing the subgroup without gestational diabetes, we found that the rate of prediabetes was 16.6% (16/96 pregnant women). In this group, blood glucose levels at 1 hour and 2 hours during the OGTT were higher compared to the normal glucose group (P < .05). A 2-hour post-OGTT glucose level of 7.78 mmol/L had a sensitivity of 93.8%, a specificity of 100%, and an area under the curve of 0.987 for diagnosing gestational prediabetes (P < .001). However, there were no statistically significant differences in the CC, CT, and TT polymorphisms of the MTHFR C677T gene among pregnant women with or without pre-gestational and GDM. Both fasting blood glucose and 2-hour glucose concentrations during the OGTT, as well as folic acid concentrations, were higher in both the pre-gestational and GDM groups compared to the non-gestational diabetes cohort. However, the analysis of MTHFR C677T polymorphisms revealed no statistically significant differences among the groups, highlighting the necessity for more extensive investigations to gain deeper insights into this relationship.


Assuntos
Diabetes Gestacional , Teste de Tolerância a Glucose , Metilenotetra-Hidrofolato Redutase (NADPH2) , Humanos , Feminino , Gravidez , Diabetes Gestacional/genética , Diabetes Gestacional/epidemiologia , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Adulto , Estudos de Casos e Controles , Glicemia/análise , Glicemia/metabolismo , Estado Pré-Diabético/genética , Estado Pré-Diabético/epidemiologia , Polimorfismo Genético , Polimorfismo de Nucleotídeo Único
19.
Pediatr Neurol ; 156: 79-84, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38733858

RESUMO

BACKGROUND: Rituximab (RTX) resistance or early B-cells repopulation were observed in children but only few publications reported the use of Obinutuzumab and no recommendations were made concerning the dosage for children. METHODS: This study was a single-center retrospective cohort study of all the children followed-up in the Pediatric Neurology Department of Necker-Enfants malades Hospital in Paris, France, and treated with obinutuzumab, between November 1, 2019, and November 1, 2021. RESULTS: A total of eight children (three females, median age 4.5 years) were treated. Seven patients presented with autoimmune encephalitis and one with myeloradiculitis. The median delay of B-cell repopulation after a course of RTX was 87 days (range 41 to 160). A switch to obinutuzumab (anti-CD20) was performed for eight children. The median duration between the first RTX infusion and obinutuzumab administration was 6.6 months. The dosage regimen for obinutuzumab was one infusion of 1000 mg/1.73 m2, that is to say 580 mg/m2 (maximum 1000 mg/infusion), by extrapolation from the adult dosage. The median delay of B-cell repopulation after one course of obinutuzumab was 230 days (range 66 to 303 days) vs 87 days after one course of RTX (P < 0.01). None of the patients presented side effects with obinutuzumab treatment. All patients had a favorable evolution at the last-follow up. Median follow-up was 1.6 years. CONCLUSIONS: This study reports the use of obinutuzumab in neurological inflammatory diseases in a pediatric population. Obinutuzumab seems to have a better biological efficacy than RTX with a longer time of B-cell repopulation.


Assuntos
Anticorpos Monoclonais Humanizados , Linfócitos B , Encefalite , Doença de Hashimoto , Fatores Imunológicos , Rituximab , Humanos , Feminino , Masculino , Rituximab/administração & dosagem , Rituximab/efeitos adversos , Rituximab/farmacologia , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/farmacologia , Pré-Escolar , Criança , Estudos Retrospectivos , Encefalite/tratamento farmacológico , Encefalite/induzido quimicamente , Linfócitos B/efeitos dos fármacos , Fatores Imunológicos/administração & dosagem , Fatores Imunológicos/efeitos adversos , Fatores Imunológicos/farmacologia , Doença de Hashimoto/tratamento farmacológico , Adolescente , Lactente
20.
ACS Nano ; 18(28): 18534-18547, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38973534

RESUMO

Cytometry plays a crucial role in characterizing cell properties, but its restricted optical window (400-850 nm) limits the number of stained fluorophores that can be detected simultaneously and hampers the study and utilization of short-wave infrared (SWIR; 900-1700 nm) fluorophores in cells. Here we introduce two SWIR-based methods to address these limitations: SWIR flow cytometry and SWIR image cytometry. We develop a quantification protocol for deducing cellular fluorophore mass. Both systems achieve a limit of detection of ∼0.1 fg cell-1 within a 30 min experimental time frame, using individualized, high-purity (6,5) single-wall carbon nanotubes as a model fluorophore and macrophage-like RAW264.7 as a model cell line. This high-sensitivity feature reveals that low-dose (6,5) serves as an antioxidant, and cell morphology and oxidative stress dose-dependently correlate with (6,5) uptake. Our SWIR cytometry holds immediate applicability for existing SWIR fluorophores and offers a solution to the issue of spectral overlapping in conventional cytometry.


Assuntos
Citometria de Fluxo , Corantes Fluorescentes , Raios Infravermelhos , Nanotubos de Carbono , Camundongos , Animais , Citometria de Fluxo/métodos , Corantes Fluorescentes/química , Nanotubos de Carbono/química , Células RAW 264.7 , Estresse Oxidativo , Macrófagos/metabolismo , Macrófagos/citologia
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