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1.
Cell ; 187(15): 4043-4060.e30, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-38878778

RESUMO

Inflammation-induced neurodegeneration is a defining feature of multiple sclerosis (MS), yet the underlying mechanisms remain unclear. By dissecting the neuronal inflammatory stress response, we discovered that neurons in MS and its mouse model induce the stimulator of interferon genes (STING). However, activation of neuronal STING requires its detachment from the stromal interaction molecule 1 (STIM1), a process triggered by glutamate excitotoxicity. This detachment initiates non-canonical STING signaling, which leads to autophagic degradation of glutathione peroxidase 4 (GPX4), essential for neuronal redox homeostasis and thereby inducing ferroptosis. Both genetic and pharmacological interventions that target STING in neurons protect against inflammation-induced neurodegeneration. Our findings position STING as a central regulator of the detrimental neuronal inflammatory stress response, integrating inflammation with glutamate signaling to cause neuronal cell death, and present it as a tractable target for treating neurodegeneration in MS.


Assuntos
Inflamação , Proteínas de Membrana , Esclerose Múltipla , Neurônios , Animais , Esclerose Múltipla/metabolismo , Esclerose Múltipla/patologia , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Camundongos , Humanos , Inflamação/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Transdução de Sinais , Autofagia , Camundongos Endogâmicos C57BL , Ácido Glutâmico/metabolismo , Ferroptose , Modelos Animais de Doenças , Feminino , Masculino
2.
Nat Rev Neurosci ; 25(7): 493-513, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38789516

RESUMO

Chronic low-grade inflammation and neuronal deregulation are two components of a smoldering disease activity that drives the progression of disability in people with multiple sclerosis (MS). Although several therapies exist to dampen the acute inflammation that drives MS relapses, therapeutic options to halt chronic disability progression are a major unmet clinical need. The development of such therapies is hindered by our limited understanding of the neuron-intrinsic determinants of resilience or vulnerability to inflammation. In this Review, we provide a neuron-centric overview of recent advances in deciphering neuronal response patterns that drive the pathology of MS. We describe the inflammatory CNS environment that initiates neurotoxicity by imposing ion imbalance, excitotoxicity and oxidative stress, and by direct neuro-immune interactions, which collectively lead to mitochondrial dysfunction and epigenetic dysregulation. The neuronal demise is further amplified by breakdown of neuronal transport, accumulation of cytosolic proteins and activation of cell death pathways. Continuous neuronal damage perpetuates CNS inflammation by activating surrounding glia cells and by directly exerting toxicity on neighbouring neurons. Further, we explore strategies to overcome neuronal deregulation in MS and compile a selection of neuronal actuators shown to impact neurodegeneration in preclinical studies. We conclude by discussing the therapeutic potential of targeting such neuronal actuators in MS, including some that have already been tested in interventional clinical trials.


Assuntos
Esclerose Múltipla , Humanos , Esclerose Múltipla/patologia , Esclerose Múltipla/metabolismo , Animais , Neurônios/patologia , Neurônios/metabolismo , Inflamação/patologia , Inflamação/metabolismo
3.
EMBO J ; 42(4): e112453, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36594364

RESUMO

Synaptic dysfunction caused by soluble ß-amyloid peptide (Aß) is a hallmark of early-stage Alzheimer's disease (AD), and is tightly linked to cognitive decline. By yet unknown mechanisms, Aß suppresses the transcriptional activity of cAMP-responsive element-binding protein (CREB), a master regulator of cell survival and plasticity-related gene expression. Here, we report that Aß elicits nucleocytoplasmic trafficking of Jacob, a protein that connects a NMDA-receptor-derived signalosome to CREB, in AD patient brains and mouse hippocampal neurons. Aß-regulated trafficking of Jacob induces transcriptional inactivation of CREB leading to impairment and loss of synapses in mouse models of AD. The small chemical compound Nitarsone selectively hinders the assembly of a Jacob/LIM-only 4 (LMO4)/ Protein phosphatase 1 (PP1) signalosome and thereby restores CREB transcriptional activity. Nitarsone prevents impairment of synaptic plasticity as well as cognitive decline in mouse models of AD. Collectively, the data suggest targeting Jacob protein-induced CREB shutoff as a therapeutic avenue against early synaptic dysfunction in AD.


Assuntos
Doença de Alzheimer , Animais , Camundongos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Camundongos Transgênicos , Neurônios/metabolismo , Sinapses/metabolismo
4.
Glia ; 72(8): 1451-1468, 2024 08.
Artigo em Inglês | MEDLINE | ID: mdl-38629411

RESUMO

The disruption of astrocytic catabolic processes contributes to the impairment of amyloid-ß (Aß) clearance, neuroinflammatory signaling, and the loss of synaptic contacts in late-onset Alzheimer's disease (AD). While it is known that the posttranslational modifications of Aß have significant implications on biophysical properties of the peptides, their consequences for clearance impairment are not well understood. It was previously shown that N-terminally pyroglutamylated Aß3(pE)-42, a significant constituent of amyloid plaques, is efficiently taken up by astrocytes, leading to the release of pro-inflammatory cytokine tumor necrosis factor α and synapse loss. Here we report that Aß3(pE)-42, but not Aß1-42, gradually accumulates within the astrocytic endolysosomal system, disrupting this catabolic pathway and inducing the formation of heteromorphous vacuoles. This accumulation alters lysosomal kinetics, lysosome-dependent calcium signaling, and upregulates the lysosomal stress response. These changes correlate with the upregulation of glial fibrillary acidic protein (GFAP) and increased activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Treatment with a lysosomal protease inhibitor, E-64, rescues GFAP upregulation, NF-κB activation, and synapse loss, indicating that abnormal lysosomal protease activity is upstream of pro-inflammatory signaling and related synapse loss. Collectively, our data suggest that Aß3(pE)-42-induced disruption of the astrocytic endolysosomal system leads to cytoplasmic leakage of lysosomal proteases, promoting pro-inflammatory signaling and synapse loss, hallmarks of AD-pathology.


Assuntos
Peptídeos beta-Amiloides , Astrócitos , Lisossomos , Astrócitos/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Lisossomos/metabolismo , Transdução de Sinais/fisiologia , Processamento de Proteína Pós-Traducional/fisiologia , Endossomos/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Fragmentos de Peptídeos/metabolismo , Camundongos , Células Cultivadas , Humanos
5.
Alzheimers Dement ; 20(2): 1166-1174, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37920945

RESUMO

INTRODUCTION: We set out to identify tau PET-positive (A+T+) individuals among amyloid-beta (Aß) positive participants using plasma biomarkers. METHODS: In this cross-sectional study we assessed 234 participants across the AD continuum who were evaluated by amyloid PET with [18 F]AZD4694 and tau-PET with [18 F]MK6240 and measured plasma levels of total tau, pTau-181, pTau-217, pTau-231, and N-terminal tau (NTA-tau). We evaluated the performances of plasma biomarkers to predict tau positivity in Aß+ individuals. RESULTS: Highest associations with tau positivity in Aß+ individuals were found for plasma pTau-217 (AUC [CI95% ] = 0.89 [0.82, 0.96]) and NTA-tau (AUC [CI95% ] = 0.88 [0.91, 0.95]). Combining pTau-217 and NTA-tau resulted in the strongest agreement (Cohen's Kappa = 0.74, CI95%  = 0.57/0.90, sensitivity = 92%, specificity = 81%) with PET for classifying tau positivity. DISCUSSION: The potential for identifying tau accumulation in later Braak stages will be useful for patient stratification and prognostication in treatment trials and in clinical practice. HIGHLIGHTS: We found that in a cohort without pre-selection pTau-181, pTau-217, and NTA-tau showed the highest association with tau PET positivity. We found that in Aß+ individuals pTau-217 and NTA-tau showed the highest association with tau PET positivity. Combining pTau-217 and NTA-tau resulted in the strongest agreement with the tau PET-based classification.


Assuntos
Doença de Alzheimer , Humanos , Proteínas tau , Estudos Transversais , Peptídeos beta-Amiloides , Biomarcadores , Tomografia por Emissão de Pósitrons
6.
J Neuroinflammation ; 20(1): 278, 2023 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-38001539

RESUMO

INTRODUCTION: Synaptic loss is closely associated with tau aggregation and microglia activation in later stages of Alzheimer's disease (AD). However, synaptic damage happens early in AD at the very early stages of tau accumulation. It remains unclear whether microglia activation independently causes synaptic cleavage before tau aggregation appears. METHODS: We investigated 104 participants across the AD continuum by measuring 14-3-3 zeta/delta ([Formula: see text]) as a cerebrospinal fluid biomarker for synaptic degradation, and fluid and imaging biomarkers of tau, amyloidosis, astrogliosis, neurodegeneration, and inflammation. We performed correlation analyses in cognitively unimpaired and impaired participants and used structural equation models to estimate the impact of microglia activation on synaptic injury in different disease stages. RESULTS: 14-3-3 [Formula: see text] was increased in participants with amyloid pathology at the early stages of tau aggregation before hippocampal volume loss was detectable. 14-3-3 [Formula: see text] correlated with amyloidosis and tau load in all participants but only with biomarkers of neurodegeneration and memory deficits in cognitively unimpaired participants. This early synaptic damage was independently mediated by sTREM2. At later disease stages, tau and astrogliosis additionally mediated synaptic loss. CONCLUSIONS: Our results advertise that sTREM2 is mediating synaptic injury at the early stages of tau accumulation, underlining the importance of microglia activation for AD disease propagation.


Assuntos
Doença de Alzheimer , Amiloidose , Humanos , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Biomarcadores/líquido cefalorraquidiano , Gliose , Proteínas tau/metabolismo , Proteínas 14-3-3
7.
Acta Neuropathol ; 146(3): 387-394, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37452829

RESUMO

Dysautonomia has substantially impacted acute COVID-19 severity as well as symptom burden after recovery from COVID-19 (long COVID), yet the underlying causes remain unknown. Here, we hypothesized that vagus nerves are affected in COVID-19 which might contribute to autonomic dysfunction. We performed a histopathological characterization of postmortem vagus nerves from COVID-19 patients and controls, and detected SARS-CoV-2 RNA together with inflammatory cell infiltration composed primarily of monocytes. Furthermore, we performed RNA sequencing which revealed a strong inflammatory response of neurons, endothelial cells, and Schwann cells which correlated with SARS-CoV-2 RNA load. Lastly, we screened a clinical cohort of 323 patients to detect a clinical phenotype of vagus nerve affection and found a decreased respiratory rate in non-survivors of critical COVID-19. Our data suggest that SARS-CoV-2 induces vagus nerve inflammation followed by autonomic dysfunction which contributes to critical disease courses and might contribute to dysautonomia observed in long COVID.


Assuntos
COVID-19 , Disautonomias Primárias , Humanos , COVID-19/complicações , SARS-CoV-2 , Síndrome de COVID-19 Pós-Aguda , RNA Viral , Células Endoteliais , Inflamação , Disautonomias Primárias/etiologia , Nervo Vago
8.
PLoS Comput Biol ; 18(2): e1009855, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35143481

RESUMO

Antimicrobial resistance presents a significant health care crisis. The mutation F98Y in Staphylococcus aureus dihydrofolate reductase (SaDHFR) confers resistance to the clinically important antifolate trimethoprim (TMP). Propargyl-linked antifolates (PLAs), next generation DHFR inhibitors, are much more resilient than TMP against this F98Y variant, yet this F98Y substitution still reduces efficacy of these agents. Surprisingly, differences in the enantiomeric configuration at the stereogenic center of PLAs influence the isomeric state of the NADPH cofactor. To understand the molecular basis of F98Y-mediated resistance and how PLAs' inhibition drives NADPH isomeric states, we used protein design algorithms in the osprey protein design software suite to analyze a comprehensive suite of structural, biophysical, biochemical, and computational data. Here, we present a model showing how F98Y SaDHFR exploits a different anomeric configuration of NADPH to evade certain PLAs' inhibition, while other PLAs remain unaffected by this resistance mechanism.


Assuntos
Antagonistas do Ácido Fólico , Infecções Estafilocócicas , Farmacorresistência Bacteriana/genética , Antagonistas do Ácido Fólico/química , Antagonistas do Ácido Fólico/farmacologia , Humanos , NADP/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Tetra-Hidrofolato Desidrogenase/química , Tetra-Hidrofolato Desidrogenase/genética , Tetra-Hidrofolato Desidrogenase/metabolismo , Trimetoprima/química , Trimetoprima/metabolismo , Trimetoprima/farmacologia
9.
Eur J Neurol ; 30(8): 2297-2304, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37159495

RESUMO

BACKGROUND AND PURPOSE: This study aimed to investigate if pre-existing neurological conditions, such as dementia and a history of cerebrovascular disease, increase the risk of severe outcomes including death, intensive care unit (ICU) admission and vascular events in patients hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 2022, when Omicron was the predominant variant. METHODS: A retrospective analysis was conducted of all patients with SARS-CoV-2 infection, confirmed by polymerase chain reaction test, admitted to the University Medical Center Hamburg-Eppendorf from 20 December 2021 until 15 August 2022. In all, 1249 patients were included in the study. In-hospital mortality was 3.8% and the ICU admission rate was 9.9%. Ninety-three patients with chronic cerebrovascular disease and 36 patients with pre-existing all-cause dementia were identified and propensity score matching by age, sex, comorbidities, vaccination status and dexamethasone treatment was performed in a 1:4 ratio with patients without the respective precondition using nearest neighbor matching. RESULTS: Analysis revealed that neither pre-existing cerebrovascular disease nor all-cause dementia increased mortality or the risk for ICU admission. All-cause dementia in the medical history also had no effect on vascular complications under investigation. In contrast, an increased odds ratio for both pulmonary artery embolism and secondary cerebrovascular events was observed in patients with pre-existing chronic cerebrovascular disease and myocardial infarction in the medical history. CONCLUSION: These findings suggest that patients with pre-existing cerebrovascular disease and myocardial infarction in their medical history may be particularly susceptible to vascular complications following SARS-CoV-2 infection with presumed Omicron variant.


Assuntos
COVID-19 , Transtornos Cerebrovasculares , Infarto do Miocárdio , Humanos , Estudos Retrospectivos , COVID-19/complicações , COVID-19/epidemiologia , SARS-CoV-2 , Transtornos Cerebrovasculares/epidemiologia
10.
Rev Neurol (Paris) ; 179(10): 1068-1073, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37596186

RESUMO

INTRODUCTION: Elderly patients are a growing population in stroke units, characterized by higher frailty, but underrepresented in clinical trials about acute care. We investigated efficacy of intravenous thrombolysis (IVT) and mechanical thrombectomy (MT) in elderlies in current practice. METHODS: We assessed consecutive patients with acute ischemic stroke (AIS) hospitalized in the four stroke units of the French Northern Alps Emergency Network between 2015 and 2020. We compared baseline characteristics, early neurological evolution and outcome of patients aged 80-89 and≥90years old (yo). RESULTS: Among 8367 patients, 2744 (32.8%) were 80-89 yo and 541 (6.5%) were≥90 yo. IVT and/or MT were performed in 787 patients≥80 yo (632 patients aged 80-89, 155 patients aged>90). Early neurological improvement was more frequent in patients≥80 yo treated by IVT and/or MT compared to untreated patients (45.6% versus 38.4%, P=0.002). After adjustment, reperfusion treatments improved likelihood of good outcome at discharge (OR=2.0 [1.6-2.7]) and reduced in-hospital mortality (OR=0.5 [0.4-0.7]). Age and initial NIHSS score were independent factors of poor functional outcome at discharge and in-hospital mortality. The rate of successful recanalization was comparable between octogenarians and nonagenarians (87% versus 85.2%, P=0.8). Octogenarians had better functional outcome at discharge compared to nonagenarians [modified Rankin scale (mRS) 0-2: 36% versus 25.7%, P=0.02], whatever IVT or MT strategy. In-hospital mortality was lower for octogenarians compared to nonagenarians (19.5% versus 27.1%, P=0.04). DISCUSSION: IVT and MT improve early neurological recovery and functional outcome at discharge of both octogenarians and nonagenarians in current practice. Despite a poorer outcome for nonagenarians than octogenarians, these reperfusion treatments should not be withheld on the basis of age only.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Trombólise Mecânica , Acidente Vascular Cerebral , Idoso , Idoso de 80 Anos ou mais , Humanos , Nonagenários , Octogenários , AVC Isquêmico/etiologia , Isquemia Encefálica/cirurgia , Isquemia Encefálica/tratamento farmacológico , Resultado do Tratamento , Acidente Vascular Cerebral/cirurgia , Acidente Vascular Cerebral/tratamento farmacológico , Trombectomia/efeitos adversos , Terapia Trombolítica , Fibrinolíticos/uso terapêutico , Estudos Retrospectivos
11.
J Neurosci ; 41(8): 1727-1737, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33334869

RESUMO

Impulsive decisions arise from preferring smaller but sooner rewards compared with larger but later rewards. How neural activity and attention to choice alternatives contribute to reward decisions during temporal discounting is not clear. Here we probed (1) attention to and (2) neural representation of delay and reward information in humans (both sexes) engaged in choices. We studied behavioral and frequency-specific dynamics supporting impulsive decisions on a fine-grained temporal scale using eye tracking and MEG recordings. In one condition, participants had to decide for themselves but pretended to decide for their best friend in a second prosocial condition, which required perspective taking. Hence, conditions varied in the value for themselves versus that pretending to choose for another person. Stronger impulsivity was reliably found across three independent groups for prosocial decisions. Eye tracking revealed a systematic shift of attention from the delay to the reward information and differences in eye tracking between conditions predicted differences in discounting. High-frequency activity (175-250 Hz) distributed over right frontotemporal sensors correlated with delay and reward information in consecutive temporal intervals for high value decisions for oneself but not the friend. Collectively, the results imply that the high-frequency activity recorded over frontotemporal MEG sensors plays a critical role in choice option integration.SIGNIFICANCE STATEMENT Humans face decisions between sooner smaller rewards and larger later rewards daily. An objective benefit of losing weight over a longer time might be devalued in face of ice cream because they prefer currently available options because of insufficiently considering long-term alternatives. The degree of contribution of neural representation and attention to choice alternatives is not clear. We investigated correlates of such decisions in participants deciding for themselves or pretending to choose for a friend. Behaviorally participants discounted less in self-choices compared with the prosocial condition. Eye movement and MEG recordings revealed how participants represent choice options most evident for options with high subjective value. These results advance our understanding of neural mechanisms underlying decision-making in humans.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Desvalorização pelo Atraso/fisiologia , Comportamento Impulsivo/fisiologia , Recompensa , Adulto , Tecnologia de Rastreamento Ocular , Feminino , Humanos , Magnetoencefalografia , Masculino , Adulto Jovem
12.
J Immunol ; 205(11): 3001-3010, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33127821

RESUMO

The voltage-gated proton channel Hv1 regulates proton fluxes across membranes, thereby influencing pH-dependent processes. Plasmacytoid dendritic cells (pDCs) require a particularly tight regulation of endosomal pH to ensure strong type I IFN secretion exclusively during infection, avoiding autoimmunity. However, whether Hv1 is important for pH control in pDCs is presently unknown. In this study, we show that mouse pDCs require Hv1 to achieve potent type I IFN responses after the recognition of foreign DNA by endosomal TLR9. Genetic disruption of Hvcn1, which encodes Hv1, impaired mouse pDC activation by CpG oligonucleotides in vitro and in vivo, reducing IFN-α secretion and the induction of IFN-stimulated genes. Mechanistically, Hvcn1 deficiency delayed endosomal acidification and enhanced intracellular reactive oxygen species production, consequently limiting protease activity and TLR9 signaling. Our study reveals a critical role of Hv1 during innate immune responses and places this channel as a key modulator of type I IFN production, the hallmark function of pDCs, commending Hv1 as an attractive target for modulating type I IFN-driven autoimmunity.


Assuntos
Células Dendríticas/metabolismo , Canais Iônicos/metabolismo , Receptor Toll-Like 9/metabolismo , Animais , Imunidade Inata/fisiologia , Interferon-alfa/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Oligodesoxirribonucleotídeos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/fisiologia
13.
PLoS Comput Biol ; 16(6): e1007447, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32511232

RESUMO

The K* algorithm provably approximates partition functions for a set of states (e.g., protein, ligand, and protein-ligand complex) to a user-specified accuracy ε. Often, reaching an ε-approximation for a particular set of partition functions takes a prohibitive amount of time and space. To alleviate some of this cost, we introduce two new algorithms into the osprey suite for protein design: fries, a Fast Removal of Inadequately Energied Sequences, and EWAK*, an Energy Window Approximation to K*. fries pre-processes the sequence space to limit a design to only the most stable, energetically favorable sequence possibilities. EWAK* then takes this pruned sequence space as input and, using a user-specified energy window, calculates K* scores using the lowest energy conformations. We expect fries/EWAK* to be most useful in cases where there are many unstable sequences in the design sequence space and when users are satisfied with enumerating the low-energy ensemble of conformations. In combination, these algorithms provably retain calculational accuracy while limiting the input sequence space and the conformations included in each partition function calculation to only the most energetically favorable, effectively reducing runtime while still enriching for desirable sequences. This combined approach led to significant speed-ups compared to the previous state-of-the-art multi-sequence algorithm, BBK*, while maintaining its efficiency and accuracy, which we show across 40 different protein systems and a total of 2,826 protein design problems. Additionally, as a proof of concept, we used these new algorithms to redesign the protein-protein interface (PPI) of the c-Raf-RBD:KRas complex. The Ras-binding domain of the protein kinase c-Raf (c-Raf-RBD) is the tightest known binder of KRas, a protein implicated in difficult-to-treat cancers. fries/EWAK* accurately retrospectively predicted the effect of 41 different sets of mutations in the PPI of the c-Raf-RBD:KRas complex. Notably, these mutations include mutations whose effect had previously been incorrectly predicted using other computational methods. Next, we used fries/EWAK* for prospective design and discovered a novel point mutation that improves binding of c-Raf-RBD to KRas in its active, GTP-bound state (KRasGTP). We combined this new mutation with two previously reported mutations (which were highly-ranked by osprey) to create a new variant of c-Raf-RBD, c-Raf-RBD(RKY). fries/EWAK* in osprey computationally predicted that this new variant binds even more tightly than the previous best-binding variant, c-Raf-RBD(RK). We measured the binding affinity of c-Raf-RBD(RKY) using a bio-layer interferometry (BLI) assay, and found that this new variant exhibits single-digit nanomolar affinity for KRasGTP, confirming the computational predictions made with fries/EWAK*. This new variant binds roughly five times more tightly than the previous best known binder and roughly 36 times more tightly than the design starting point (wild-type c-Raf-RBD). This study steps through the advancement and development of computational protein design by presenting theory, new algorithms, accurate retrospective designs, new prospective designs, and biochemical validation.


Assuntos
Biologia Computacional , Engenharia de Proteínas/métodos , Proteínas Proto-Oncogênicas c-raf/química , Proteínas Proto-Oncogênicas p21(ras)/química , Algoritmos , Computadores , Humanos , Interferometria , Lectinas/química , Ligantes , Modelos Estatísticos , Linguagens de Programação , Ligação Proteica , Domínios Proteicos , Software
14.
An Acad Bras Cienc ; 93(1): e20190425, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33825789

RESUMO

Conyza species are important weeds in global agriculture, especially due to their capacity to evolve resistance to multiple herbicide mechanisms of action. We aimed to evaluate the frequency and distribution of resistance to glyphosate and chlorimuron-ethyl in Conyza spp. populations from Brazil. Seed samples were collected from grain production areas across nine Brazilian states over five consecutive years (2014 to 2018). Prior to resistance monitoring trials, dose-response assays were conducted to determine a single dose of glyphosate or chlorimuron-ethyl to discriminate resistant and susceptible populations. Resistance monitoring based on plant responses to the application of discriminatory doses of glyphosate (960 g ha-1) or chlorimuron-ethyl (20 g ha-1). Populations were classified as resistant, moderately resistant, or susceptible to either herbicide. While glyphosate resistance was highly frequent (71.2%) in all the five years, chlorimuron-ethyl resistant populations occurred at 39.8% of the total. The frequency of multiple resistance to both herbicides (35.3%) was proportional to the occurrence of chlorimuron-ethyl resistance (39.6%). Resistance to glyphosate and to chlorimuron-ethyl were found across all states evaluated.


Assuntos
Conyza , Herbicidas , Brasil , Glicina/análogos & derivados , Glicina/farmacologia , Resistência a Herbicidas , Herbicidas/farmacologia , Glifosato
15.
Anal Chem ; 92(7): 5222-5230, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32146809

RESUMO

Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is widely used to visualize and analyze the distribution of membrane lipids in an increasingly large number of applications. In this context, different lipoforms of glycerophospholipids (GPLs) are among the prime targets of interest. For this group of analytes, however, ion suppression effects have been described to strongly favor the detection of certain GPL classes over others, thereby hampering the analysis of suppressed species and greatly restraining quantitative analysis. These effects are generally attributed to the distribution of available charge carriers during the MALDI process. Here, we present a systematic investigation of charge distribution between different classes of GPL under MALDI-MSI conditions. For this, we constructed arrays of artificial tissues with different formulated lipid composition that contained predefined amounts of only two specific GPL classes and analyzed them with MALDI-MSI in positive- and negative-ion modes. Next to a characterization of expected ion suppression effects, analysis of these binary systems revealed yet undescribed signal intensity enhancement for the combinations of certain GPL classes. Furthermore, the comprehensive data allowed us to compile a hierarchy of charge affinities for the investigated GPL classes in both polarities. Additional experiments revealed that laser post-ionization (MALDI-2) has great potential to overwrite changes in signal intensity caused by charge distribution among different GPL classes observed in standard MALDI-MSI.


Assuntos
Glicerofosfolipídeos/análise , Estrutura Molecular , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
16.
Ecotoxicol Environ Saf ; 193: 110336, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32092581

RESUMO

Aquatic environments contaminated by lead (Pb) are a problem in many regions of world. Since Pb has high toxicity, the identification of species for phytoremediation is important for the recovery of these areas. Thus, the phytoremediation potential of Panicum aquaticum Poir. (Poaceae) was evaluated. The anatomical and physiological responses of P. aquaticum were assessed under different concentrations of Pb [0.0, 0.5, 1.0, 2.0, 4.0, and 8.0 mM of Pb(NO3)2]. Plant growth, anatomy of roots and leaves, root uptake, root to shoot translocation, and the concentration and accumulation of Pb in organs were analyzed. Regarding leaf anatomy, Pb treatment led to changes in epidermis thickness, stomatal density, stomatal diameter, and sclerenchymal area. Endoderm thickness was increased at the highest concentrations of Pb, which may be related to reduced translocation and shoot accumulation. The roots of P. aquaticum presented increased absorption (2279 µg g-1 DW-1 of Pb). In conclusion, P. aquaticum was found to have potential for the phytoremediation of areas contaminated with Pb.


Assuntos
Chumbo/farmacocinética , Panicum/metabolismo , Poluentes Químicos da Água/farmacocinética , Biodegradação Ambiental , Chumbo/toxicidade , Panicum/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Poluentes Químicos da Água/toxicidade
17.
Pestic Biochem Physiol ; 164: 1-6, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32284114

RESUMO

Sourgrass (Digitaria insularis) is one of the most problematic weeds in South America because glyphosate resistance is widespread across most crop production regions. Acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicides have been intensively used to manage D. insularis, which substantially increased selection pressure for this class of herbicides. We confirmed resistance to ACCase herbicides in a D. insularis population from Brazil and characterized its molecular basis. Resistant plants showed high level of resistance to haloxyfop (resistance factor, RF = 613-fold), low level of resistance to pinoxaden (RF = 3.6-fold), and no resistance to clethodim. A target-site mutation, Trp2027Cys, was found in the ACCase sequence from resistant plants. A protein homology model shows that the Trp2027Cys mutation is near the herbicide-binding pocket formed between two ACCase chains, and is predicted to obstruct the access of aryloxyphenoxypropionates (FOP) herbicides to the binding site. A qPCR-based single nucleotide polymorphism genotyping method was validated to discriminate susceptible (wild-type Trp2027) and resistant (mutant Cys2027) alleles. All resistant plants were homozygous for the mutation and the assay could be used for early detection of resistance in D. insularis field samples with suspected resistance to ACCase inhibitors.


Assuntos
Digitaria , Herbicidas , Acetil-CoA Carboxilase , Brasil , Resistência a Herbicidas , Mutação , Poaceae
18.
J Intern Med ; 286(6): 702-710, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31319000

RESUMO

BACKGROUND: Bradykinin-mediated angioedema (AE) is a complication associated with thrombolysis for acute ischemic stroke. Risk factors are unknown and management is discussed. OBJECTIVES: To clarify risk factors associated with bradykinin-mediated AE after thrombolysis for acute ischemic stroke. METHODS: In a case-control study conducted at a French reference centre for bradykinin angiœdema, patients with thrombolysis for acute ischemic stroke and a diagnosis of bradykinin-mediated angiœdema, were compared to controls treated with thrombolysis treatment without angiœdema. RESULTS: Fifty-three thrombolysis-related AE were matched to 106 control subjects. The sites of attacks following thrombolysis for ischemic stroke mainly included tongue (34/53, 64%) and lips (26/53, 49%). The upper airways were involved in 37 (70%) cases. Three patients required mechanical ventilation. Patients with bradykinin-mediated angiœdema were more frequently women [33 (62%) vs. 44 (42%); P = 0.01], had higher frequency of prior ischemic stroke [12 (23%) vs. 9 (8%); P = 0.01], hypertension [46 (87%) vs. 70 (66%); P = 0.005], were more frequently treated with angiotensin-converting enzyme inhibitor [37 (70%) vs. 28 (26%); P < 0.001] and were more frequently hospitalized in intensive care medicine [ICU; 11 (21%) vs. 5 (5%); P = 0.004]. In multivariate analysis, factors associated with thrombolysis-related AE were female sex [odds ratio (OR), 3.04; 95% confident interval (CI), 1.32-7.01; P = 0.009] and treatment with angiotensin-converting enzyme inhibitors [(OR), 6.08; 95% (CI), 2.17-17.07; P < 0.001]. CONCLUSIONS: This case-control study points out angiotensin-converting enzyme inhibitors and female sex as risk factors of bradykinin AE associated with thrombolysis for ischemic stroke.


Assuntos
Angioedema/induzido quimicamente , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Isquemia Encefálica/tratamento farmacológico , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/efeitos adversos , Idoso , Bradicinina , Estudos de Casos e Controles , Feminino , França , Humanos , Masculino , Fatores de Risco , Fatores Sexuais
19.
J Comput Chem ; 39(30): 2494-2507, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30368845

RESUMO

We present osprey 3.0, a new and greatly improved release of the osprey protein design software. Osprey 3.0 features a convenient new Python interface, which greatly improves its ease of use. It is over two orders of magnitude faster than previous versions of osprey when running the same algorithms on the same hardware. Moreover, osprey 3.0 includes several new algorithms, which introduce substantial speedups as well as improved biophysical modeling. It also includes GPU support, which provides an additional speedup of over an order of magnitude. Like previous versions of osprey, osprey 3.0 offers a unique package of advantages over other design software, including provable design algorithms that account for continuous flexibility during design and model conformational entropy. Finally, we show here empirically that osprey 3.0 accurately predicts the effect of mutations on protein-protein binding. Osprey 3.0 is available at http://www.cs.duke.edu/donaldlab/osprey.php as free and open-source software. © 2018 Wiley Periodicals, Inc.


Assuntos
Conformação Proteica , Proteínas/química , Software , Algoritmos , Modelos Moleculares , Ligação Proteica
20.
Phys Rev Lett ; 120(26): 261301, 2018 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-30004767

RESUMO

The radial acceleration measured in bright galaxies tightly correlates with that generated by the observed distribution of baryons, a phenomenon known as the radial acceleration relation (RAR). Dwarf spheroidal satellite galaxies have been recently found to depart from the extrapolation of the RAR measured for more massive objects but with a substantially larger scatter. If confirmed by new data, this result provides a powerful test of the theory of gravity at low accelerations that requires robust theoretical predictions. By using high-resolution hydrodynamical simulations, we show that, within the standard model of cosmology (ΛCDM), satellite galaxies are expected to follow the same RAR as brighter systems but with a much larger scatter which does not correlate with the physical properties of the galaxies. In the simulations, the RAR evolves mildly with redshift. Moreover, the acceleration due to the gravitational field of the host has no effect on the RAR. This is in contrast with the external field effect in modified Newtonian dynamics (MOND) which causes galaxies in strong external fields to deviate from the RAR. This difference between ΛCDM and MOND offers a possible way to discriminate between them.

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