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1.
Cell ; 163(3): 684-97, 2015 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-26496608

RESUMO

The central role of translation in modulating gene activity has long been recognized, yet the systematic exploration of quantitative changes in translation at a genome-wide scale in response to a specific stimulus has only recently become technically feasible. Using the well-characterized signaling pathway of the phytohormone ethylene and plant-optimized genome-wide ribosome footprinting, we have uncovered a molecular mechanism linking this hormone's perception to the activation of a gene-specific translational control mechanism. Characterization of one of the targets of this translation regulatory machinery, the ethylene signaling component EBF2, indicates that the signaling molecule EIN2 and the nonsense-mediated decay proteins UPFs play a central role in this ethylene-induced translational response. Furthermore, the 3'UTR of EBF2 is sufficient to confer translational regulation and required for the proper activation of ethylene responses. These findings represent a mechanistic paradigm of gene-specific regulation of translation in response to a key growth regulator.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Biossíntese de Proteínas , Receptores de Superfície Celular/metabolismo , Transdução de Sinais , Regiões 3' não Traduzidas , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Ligação a DNA , Etilenos/metabolismo , Proteínas F-Box/genética , Regulação da Expressão Gênica de Plantas , Proteínas Nucleares/metabolismo , RNA Mensageiro/metabolismo , Ribossomos/metabolismo , Fatores de Transcrição/metabolismo
2.
Plant Cell ; 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38411602

RESUMO

Arabidopsis thaliana is currently the most-studied plant species on earth, with an unprecedented number of genetic, genomic, and molecular resources having been generated in this plant model. In the era of translating foundational discoveries to crops and beyond, we aimed to highlight the utility and challenges of using Arabidopsis as a reference for applied plant biology research, agricultural innovation, biotechnology, and medicine. We hope that this review will inspire the next generation of plant biologists to continue leveraging Arabidopsis as a robust and convenient experimental system to address fundamental and applied questions in biology. We aim to encourage lab and field scientists alike to take advantage of the vast Arabidopsis datasets, annotations, germplasm, constructs, methods, molecular and computational tools in our pursuit to advance understanding of plant biology and help feed the world's growing population. We envision that the power of Arabidopsis-inspired biotechnologies and foundational discoveries will continue to fuel the development of resilient, high-yielding, nutritious plants for the betterment of plant and animal health and greater environmental sustainability.

3.
N Engl J Med ; 388(5): 427-438, 2023 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-36724329

RESUMO

BACKGROUND: In September 2015, the four-component, protein-based meningococcal serogroup B vaccine (4CMenB; Bexsero) became available for private purchase in Spain. METHODS: We conducted a nationwide matched case-control study to assess the effectiveness of 4CMenB in preventing invasive meningococcal disease in children. The study included all laboratory-confirmed cases of invasive meningococcal disease in children younger than 60 months of age between October 5, 2015, and October 6, 2019, in Spain. Each case patient was matched with four controls according to date of birth and province. 4CMenB vaccination status of the case patients and controls was compared with the use of multivariate conditional logistic regression. RESULTS: We compared 306 case patients (243 [79.4%] with serogroup B disease) with 1224 controls. A total of 35 case patients (11.4%) and 298 controls (24.3%) had received at least one dose of 4CMenB. The effectiveness of complete vaccination with 4CMenB (defined as receipt of at least 2 doses, administered in accordance with the manufacturer's recommendations) was 76% (95% confidence interval [CI], 57 to 87) against invasive meningococcal disease caused by any serogroup, and partial vaccination was 54% (95% CI, 18 to 74) effective. Complete vaccination resulted in an effectiveness of 71% (95% CI, 45 to 85) against meningococcal serogroup B disease. Vaccine effectiveness with at least one dose of 4CMenB was 64% (95% CI, 41 to 78) against serogroup B disease and 82% (95% CI, 21 to 96) against non-serogroup B disease. With the use of the genetic Meningococcal Antigen Typing System, serogroup B strains that were expected to be covered by 4CMenB were detected in 44 case patients, none of whom had been vaccinated. CONCLUSIONS: Complete vaccination with 4CMenB was found to be effective in preventing invasive disease by serogroup B and non-serogroup B meningococci in children younger than 5 years of age.


Assuntos
Infecções Meningocócicas , Vacinas Meningocócicas , Neisseria meningitidis Sorogrupo B , Criança , Humanos , Lactente , Estudos de Casos e Controles , Infecções Meningocócicas/microbiologia , Infecções Meningocócicas/prevenção & controle , Vacinas Meningocócicas/uso terapêutico , Neisseria meningitidis , Espanha
4.
Blood ; 144(6): 646-656, 2024 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-38843478

RESUMO

ABSTRACT: Fostamatinib, a recently approved Syk inhibitor used in adult primary immune thrombocytopenia (ITP), has been shown to be safe and effective in this disorder. However, clinical trial results may not be similarly reproduced in clinical practice. Here, 138 patients with ITP (both primary and secondary) from 42 Spanish centers who had been treated with fostamatinib were evaluated prospectively and retrospectively. The median age of our cohort (55.8% women) was 66 years (interquartile range [IQR], 56-80). The median time since ITP diagnosis at fostamatinib initiation was 51 months (IQR, 10-166). The median number of therapies before fostamatinib initiation was 4 (IQR, 2-5), including eltrombopag (76.1%), romiplostim (57.2%), and IV immunoglobulins (44.2%). Fifty-eight patients (42.0%) had signs/symptoms of bleeding in the month before treatment initiation. Seventy-nine percent of patients responded to fostamatinib with 53.6% complete responses (platelet count > 100 × 109/L). Eighty-three patients (60.1%) received fostamatinib monotherapy, achieving a high response rate (85.4%). The proportion of time in response during the 27-month period examined was 83.3%. The median time to platelet response was 11 days (IQR, 7-21). Sixty-seven patients (48.5%) experienced adverse events, mainly grade 1 to 2; the commonest of which were diarrhea (n = 28) and hypertension (n = 21). One patient had deep venous thrombosis, and one patient developed acute myocardial infarction. Fostamatinib was shown to be effective with good safety profile in patients with primary and secondary ITP across a wide age spectrum in this real-world study.


Assuntos
Aminopiridinas , Morfolinas , Oxazinas , Púrpura Trombocitopênica Idiopática , Piridinas , Pirimidinas , Humanos , Feminino , Masculino , Pessoa de Meia-Idade , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Idoso , Oxazinas/uso terapêutico , Oxazinas/efeitos adversos , Idoso de 80 Anos ou mais , Pirimidinas/uso terapêutico , Pirimidinas/efeitos adversos , Morfolinas/uso terapêutico , Morfolinas/efeitos adversos , Piridinas/uso terapêutico , Piridinas/efeitos adversos , Aminopiridinas/uso terapêutico , Aminopiridinas/efeitos adversos , Estudos Retrospectivos , Resultado do Tratamento , Quinase Syk/antagonistas & inibidores , Inibidores de Proteínas Quinases/uso terapêutico , Inibidores de Proteínas Quinases/efeitos adversos , Contagem de Plaquetas , Estudos Prospectivos
5.
J Neurosci ; 44(19)2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38485258

RESUMO

The superior colliculus receives powerful synaptic inputs from corticotectal neurons in the visual cortex. The function of these corticotectal neurons remains largely unknown due to a limited understanding of their response properties and connectivity. Here, we use antidromic methods to identify corticotectal neurons in awake male and female rabbits, and measure their axonal conduction times, thalamic inputs and receptive field properties. All corticotectal neurons responded to sinusoidal drifting gratings with a nonlinear (nonsinusoidal) increase in mean firing rate but showed pronounced differences in their ON-OFF receptive field structures that we classified into three groups, Cx, S2, and S1. Cx receptive fields had highly overlapping ON and OFF subfields as classical complex cells, S2 had largely separated ON and OFF subfields as classical simple cells, and S1 had a single ON or OFF subfield. Thus, all corticotectal neurons are homogeneous in their nonlinear spatial summation but very heterogeneous in their spatial integration of ON and OFF inputs. The Cx type had the fastest conducting axons, the highest spontaneous activity, and the strongest and fastest visual responses. The S2 type had the highest orientation selectivity, and the S1 type had the slowest conducting axons. Moreover, our cross-correlation analyses found that a subpopulation of corticotectal neurons with very fast conducting axons and high spontaneous firing rates (largely "Cx" type) receives monosynaptic input from retinotopically aligned thalamic neurons. This previously unrecognized fast-conducting thalamic-mediated corticotectal pathway may provide specialized information to superior colliculus and prime recipient neurons for subsequent corticotectal or retinal synaptic input.


Assuntos
Neurônios , Sinapses , Tálamo , Córtex Visual , Vias Visuais , Vigília , Animais , Coelhos , Masculino , Feminino , Vias Visuais/fisiologia , Vigília/fisiologia , Córtex Visual/fisiologia , Córtex Visual/citologia , Sinapses/fisiologia , Neurônios/fisiologia , Tálamo/fisiologia , Tálamo/citologia , Estimulação Luminosa/métodos , Campos Visuais/fisiologia , Potenciais de Ação/fisiologia , Colículos Superiores/fisiologia , Colículos Superiores/citologia
6.
J Neurosci ; 44(3)2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38050109

RESUMO

The human visual cortex processes light and dark stimuli with ON and OFF pathways that are differently modulated by luminance contrast. We have previously demonstrated that ON cortical pathways have higher contrast sensitivity than OFF cortical pathways and the difference increases with luminance range (defined as the maximum minus minimum luminance in the scene). Here, we demonstrate that these ON-OFF cortical differences are already present in the human retina and that retinal responses measured with electroretinography are more affected by reductions in luminance range than cortical responses measured with electroencephalography. Moreover, we show that ON-OFF pathway differences measured with electroretinography become more pronounced in myopia, a visual disorder that elongates the eye and blurs vision at far distance. We find that, as the eye axial length increases across subjects, ON retinal pathways become less responsive, slower in response latency, less sensitive, and less effective and slower at driving pupil constriction. Based on these results, we conclude that myopia is associated with a deficit in ON pathway function that decreases the ability of the retina to process low contrast and regulate retinal illuminance in bright environments.


Assuntos
Sensibilidades de Contraste , Miopia , Humanos , Retina/fisiologia , Visão Ocular , Eletrorretinografia , Estimulação Luminosa
7.
Circ Res ; 133(2): 120-137, 2023 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-37313722

RESUMO

BACKGROUND: Beta-2 adrenergic receptors (ß2ARs) but not beta-2 adrenergic receptors (ß1ARs) form a functional complex with L-type Ca2+ channels (LTCCs) on the cardiomyocyte membrane. However, how microdomain localization in the plasma membrane affects the function of these complexes is unknown. We aim to study the coupling between LTCC and ß adrenergic receptors in different cardiomyocyte microdomains, the distinct involvement of PKA and CAMKII (Ca2+/calmodulin-dependent protein kinase II) and explore how this functional complex is disrupted in heart failure. METHODS: Global signaling between LTCCs and ß adrenergic receptors was assessed with whole-cell current recordings and western blot analysis. Super-resolution scanning patch-clamp was used to explore the local coupling between single LTCCs and ß1AR or ß2AR in different membrane microdomains in control and failing cardiomyocytes. RESULTS: LTCC open probability (Po) showed an increase from 0.054±0.003 to 0.092±0.008 when ß2AR was locally stimulated in the proximity of the channel (<350 nm) in the transverse tubule microdomain. In failing cardiomyocytes, from both rodents and humans, this transverse tubule coupling between LTCC and ß2AR was lost. Interestingly, local stimulation of ß1AR did not elicit any change in the Po of LTCCs, indicating a lack of proximal functional interaction between the two, but we confirmed a general activation of LTCC via ß1AR. By using blockers of PKA and CaMKII and a Caveolin-3-knockout mouse model, we conclude that the ß2AR-LTCC regulation requires the presence of caveolin-3 and the activation of the CaMKII pathway. By contrast, at a cellular "global" level PKA plays a major role downstream ß1AR and results in an increase in LTCC current. CONCLUSIONS: Regulation of the LTCC activity by proximity coupling mechanisms occurs only via ß2AR, but not ß1AR. This may explain how ß2ARs tune the response of LTCCs to adrenergic stimulation in healthy conditions. This coupling is lost in heart failure; restoring it could improve the adrenergic response of failing cardiomyocytes.


Assuntos
Caveolina 3 , Insuficiência Cardíaca , Camundongos , Animais , Humanos , Caveolina 3/genética , Caveolina 3/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Insuficiência Cardíaca/metabolismo , Miócitos Cardíacos/metabolismo , Receptores Adrenérgicos beta/metabolismo , Receptores Adrenérgicos beta 2/genética , Receptores Adrenérgicos beta 2/metabolismo , Adrenérgicos , Canais de Cálcio Tipo L/metabolismo
8.
Circ Res ; 133(11): 944-958, 2023 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-37869877

RESUMO

BACKGROUND: ß1AR (beta-1 adrenergic receptor) and ß2AR (beta-2 adrenergic receptor)-mediated cyclic adenosine monophosphate signaling has distinct effects on cardiac function and heart failure progression. However, the mechanism regulating spatial localization and functional compartmentation of cardiac ß-ARs remains elusive. Emerging evidence suggests that microtubule-dependent trafficking of mRNP (messenger ribonucleoprotein) and localized protein translation modulates protein compartmentation in cardiomyocytes. We hypothesized that ß-AR compartmentation in cardiomyocytes is accomplished by selective trafficking of its mRNAs and localized translation. METHODS: The localization pattern of ß-AR mRNA was investigated using single molecule fluorescence in situ hybridization and subcellular nanobiopsy in rat cardiomyocytes. The role of microtubule on ß-AR mRNA localization was studied using vinblastine, and its effect on receptor localization and function was evaluated with immunofluorescent and high-throughput Förster resonance energy transfer microscopy. An mRNA protein co-detection assay identified plausible ß-AR translation sites in cardiomyocytes. The mechanism by which ß-AR mRNA is redistributed post-heart failure was elucidated by single molecule fluorescence in situ hybridization, nanobiopsy, and high-throughput Förster resonance energy transfer microscopy on 16 weeks post-myocardial infarction and detubulated cardiomyocytes. RESULTS: ß1AR and ß2AR mRNAs show differential localization in cardiomyocytes, with ß1AR found in the perinuclear region and ß2AR showing diffuse distribution throughout the cell. Disruption of microtubules induces a shift of ß2AR transcripts toward the perinuclear region. The close proximity between ß2AR transcripts and translated proteins suggests that the translation process occurs in specialized, precisely defined cellular compartments. Redistribution of ß2AR transcripts is microtubule-dependent, as microtubule depolymerization markedly reduces the number of functional receptors on the membrane. In failing hearts, both ß1AR and ß2AR mRNAs are redistributed toward the cell periphery, similar to what is seen in cardiomyocytes undergoing drug-induced detubulation. This suggests that t-tubule remodeling contributes to ß-AR mRNA redistribution and impaired ß2AR function in failing hearts. CONCLUSIONS: Asymmetrical microtubule-dependent trafficking dictates differential ß1AR and ß2AR localization in healthy cardiomyocyte microtubules, underlying the distinctive compartmentation of the 2 ß-ARs on the plasma membrane. The localization pattern is altered post-myocardial infarction, resulting from transverse tubule remodeling, leading to distorted ß2AR-mediated cyclic adenosine monophosphate signaling.


Assuntos
Insuficiência Cardíaca , Infarto do Miocárdio , Ratos , Animais , Hibridização in Situ Fluorescente , Insuficiência Cardíaca/metabolismo , Receptores Adrenérgicos beta 2/genética , Receptores Adrenérgicos beta 2/metabolismo , Infarto do Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , AMP Cíclico/metabolismo , Receptores Adrenérgicos beta 1/metabolismo , Microtúbulos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Monofosfato de Adenosina/metabolismo , Monofosfato de Adenosina/farmacologia
9.
Biochem J ; 481(5): 387-403, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38373073

RESUMO

The dynamic nature of the microtubule network is dependent in part by post-translational modifications (PTMs) - particularly through acetylation, which stabilizes the microtubule network. Whether PTMs of the microtubule network in vascular smooth muscle cells (VSMCs) contribute to the pathophysiology of hypertension is unknown. The aim of this study was to determine the acetylated state of the microtubule network in the mesenteric arteries of spontaneously hypertensive rats (SHR). Experiments were performed on male normotensive rats and SHR mesenteric arteries. Western blotting and mass spectrometry determined changes in tubulin acetylation. Wire myography was used to investigate the effect of tubacin on isoprenaline-mediated vasorelaxations. Isolated cells from normotensive rats were used for scanning ion conductance microscopy (SICM). Mass spectrometry and Western blotting showed that tubulin acetylation is increased in the mesenteric arteries of the SHR compared with normotensive rats. Tubacin enhanced the ß-adrenoceptor-mediated vasodilatation by isoprenaline when the endothelium was intact, but attenuated relaxations when the endothelium was denuded or nitric oxide production was inhibited. By pre-treating vessels with colchicine to disrupt the microtubule network, we were able to confirm that the effects of tubacin were microtubule-dependent. Using SICM, we examined the cell surface Young's modulus of VSMCs, but found no difference in control, tubacin-treated, or taxol-treated cells. Acetylation of tubulin at Lys40 is elevated in mesenteric arteries from the SHR. Furthermore, this study shows that tubacin has an endothelial-dependent bimodal effect on isoprenaline-mediated vasorelaxation.


Assuntos
Anilidas , Ácidos Hidroxâmicos , Hipertensão , Tubulina (Proteína) , Ratos , Animais , Masculino , Ratos Endogâmicos WKY , Acetilação , Isoproterenol/farmacologia , Ratos Endogâmicos SHR , Artérias Mesentéricas , Vasodilatação , Microtúbulos , Endotélio Vascular/fisiologia
10.
J Neurosci ; 43(6): 993-1007, 2023 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-36535768

RESUMO

Human vision processes light and dark stimuli in visual scenes with separate ON and OFF neuronal pathways. In nature, stimuli lighter or darker than their local surround have different spatial properties and contrast distributions (Ratliff et al., 2010; Cooper and Norcia, 2015; Rahimi-Nasrabadi et al., 2021). Similarly, in human vision, we show that luminance contrast affects the perception of lights and darks differently. At high contrast, human subjects of both sexes locate dark stimuli faster and more accurately than light stimuli, which is consistent with a visual system dominated by the OFF pathway. However, at low contrast, they locate light stimuli faster and more accurately than dark stimuli, which is consistent with a visual system dominated by the ON pathway. Luminance contrast was strongly correlated with multiple ON/OFF dominance ratios estimated from light/dark ratios of performance errors, missed targets, or reaction times (RTs). All correlations could be demonstrated at multiple eccentricities of the central visual field with an ON-OFF perimetry test implemented in a head-mounted visual display. We conclude that high-contrast stimuli are processed faster and more accurately by OFF pathways than ON pathways. However, the OFF dominance shifts toward ON dominance when stimulus contrast decreases, as expected from the higher-contrast sensitivity of ON cortical pathways (Kremkow et al., 2014; Rahimi-Nasrabadi et al., 2021). The results highlight the importance of contrast polarity in visual field measurements and predict a loss of low-contrast vision in humans with ON pathway deficits, as demonstrated in animal models (Sarnaik et al., 2014).SIGNIFICANCE STATEMENT ON and OFF retino-thalamo-cortical pathways respond differently to luminance contrast. In both animal models and humans, low contrasts drive stronger responses from ON pathways, whereas high contrasts drive stronger responses from OFF pathways. We demonstrate that these ON-OFF pathway differences have a correlate in human vision. At low contrast, humans locate light targets faster and more accurately than dark targets but, as contrast increases, dark targets become more visible than light targets. We also demonstrate that contrast is strongly correlated with multiple light/dark ratios of visual performance in central vision. These results provide a link between neuronal physiology and human vision while emphasizing the importance of stimulus polarity in measurements of visual fields and contrast sensitivity.


Assuntos
Córtex Visual , Masculino , Animais , Feminino , Humanos , Córtex Visual/fisiologia , Visão Ocular , Campos Visuais , Sensibilidades de Contraste , Vias Visuais/fisiologia , Estimulação Luminosa , Percepção Visual/fisiologia
11.
J Physiol ; 602(10): 2227-2251, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38690610

RESUMO

Passive whole-body hyperthermia increases limb blood flow and cardiac output ( Q ̇ $\dot Q$ ), but the interplay between peripheral and central thermo-haemodynamic mechanisms remains unclear. Here we tested the hypothesis that local hyperthermia-induced alterations in peripheral blood flow and blood kinetic energy modulate flow to the heart and Q ̇ $\dot Q$ . Body temperatures, regional (leg, arm, head) and systemic haemodynamics, and left ventricular (LV) volumes and functions were assessed in eight healthy males during: (1) 3 h control (normothermic condition); (2) 3 h of single-leg heating; (3) 3 h of two-leg heating; and (4) 2.5 h of whole-body heating. Leg, forearm, and extracranial blood flow increased in close association with local rises in temperature while brain perfusion remained unchanged. Increases in blood velocity with small to no changes in the conduit artery diameter underpinned the augmented limb and extracranial perfusion. In all heating conditions, Q ̇ $\dot Q$ increased in association with proportional elevations in systemic vascular conductance, related to enhanced blood flow, blood velocity, vascular conductance and kinetic energy in the limbs and head (all R2 ≥ 0.803; P < 0.001), but not in the brain. LV systolic (end-systolic elastance and twist) and diastolic functional profiles (untwisting rate), pulmonary ventilation and systemic aerobic metabolism were only altered in whole-body heating. These findings substantiate the idea that local hyperthermia-induced selective alterations in peripheral blood flow modulate the magnitude of flow to the heart and Q ̇ $\dot Q$ through changes in blood velocity and kinetic energy. Localised heat-activated events in the peripheral circulation therefore affect the human heart's output. KEY POINTS: Local and whole-body hyperthermia increases limb and systemic perfusion, but the underlying peripheral and central heat-sensitive mechanisms are not fully established. Here we investigated the regional (leg, arm and head) and systemic haemodynamics (cardiac output: Q ̇ $\dot Q$ ) during passive single-leg, two-leg and whole-body hyperthermia to determine the contribution of peripheral and central thermosensitive factors in the control of human circulation. Single-leg, two-leg, and whole-body hyperthermia induced graded increases in leg blood flow and Q ̇ $\dot Q$ . Brain blood flow, however, remained unchanged in all conditions. Ventilation, extracranial blood flow and cardiac systolic and diastolic functions only increased during whole-body hyperthermia. The augmented Q ̇ $\dot Q$ with hyperthermia was tightly related to increased limb and head blood velocity, flow and kinetic energy. The findings indicate that local thermosensitive mechanisms modulate regional blood velocity, flow and kinetic energy, thereby controlling the magnitude of flow to the heart and thus the coupling of peripheral and central circulation during hyperthermia.


Assuntos
Débito Cardíaco , Hipertermia , Humanos , Masculino , Adulto , Hipertermia/fisiopatologia , Débito Cardíaco/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Febre/fisiopatologia , Adulto Jovem , Temperatura Alta , Hemodinâmica
12.
J Am Chem Soc ; 146(31): 21264-21270, 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39052124

RESUMO

Herein, we describe nickel oxidative addition complexes (Ni-OACs) of drug-like molecules as a platform to rapidly generate lead candidates with enhanced C(sp3) fraction. The potential of Ni-OACs to access new chemical space has been assessed not only in C(sp2)-C(sp3) couplings but also in additional bond formations without recourse to specialized ligands and with improved generality when compared to Ni-catalyzed reactions. The development of an automated diversification process further illustrates the robustness of Ni-OACs, thus offering a new gateway to expedite the design-make-test-analyze (DMTA) cycle in drug discovery.

13.
J Hepatol ; 80(1): 73-81, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37852414

RESUMO

BACKGROUND & AIMS: Pre-emptive transjugular intrahepatic portosystemic shunt (TIPS) is the treatment of choice for high-risk acute variceal bleeding (AVB; i.e., Child-Turcotte-Pugh [CTP] B8-9+active bleeding/C10-13). Nevertheless, some 'non-high-risk' patients have poor outcomes despite the combination of non-selective beta-blockers and endoscopic variceal ligation for secondary prophylaxis. We investigated prognostic factors for re-bleeding and mortality in 'non-high-risk' AVB to identify subgroups who may benefit from more potent treatments (i.e., TIPS) to prevent further decompensation and mortality. METHODS: A total of 2,225 adults with cirrhosis and variceal bleeding were prospectively recruited at 34 centres between 2011-2015; for the purpose of this study, case definitions and information on prognostic indicators at index AVB and on day 5 were further refined in low-risk patients, of whom 581 (without failure to control bleeding or contraindications to TIPS) who were managed by non-selective beta-blockers/endoscopic variceal ligation, were finally included. Patients were followed for 1 year. RESULTS: Overall, 90 patients (15%) re-bled and 70 (12%) patients died during follow-up. Using clinical routine data, no meaningful predictors of re-bleeding were identified. However, re-bleeding (included as a time-dependent co-variable) increased mortality, even after accounting for differences in patient characteristics (adjusted cause-specific hazard ratio: 2.57; 95% CI 1.43-4.62; p = 0.002). A nomogram including CTP, creatinine, and sodium measured at baseline accurately (concordance: 0.752) stratified the risk of death. CONCLUSION: The majority of 'non-high-risk' patients with AVB have an excellent prognosis, if treated according to current recommendations. However, about one-fifth of patients, i.e. those with CTP ≥8 and/or high creatinine levels or hyponatremia, have a considerable risk of death within 1 year of the index bleed. Future clinical trials should investigate whether elective TIPS placement reduces mortality in these patients. IMPACT AND IMPLICATIONS: Pre-emptive transjugular intrahepatic portosystemic shunt placement improves outcomes in high-risk acute variceal bleeding; nevertheless, some 'non-high-risk' patients have poor outcomes despite the combination of non-selective beta-blockers and endoscopic variceal ligation. This is the first large-scale study investigating prognostic factors for re-bleeding and mortality in 'non-high-risk' acute variceal bleeding. While no clinically meaningful predictors were identified for re-bleeding, we developed a nomogram integrating baseline Child-Turcotte-Pugh score, creatinine, and sodium to stratify mortality risk. Our study paves the way for future clinical trials evaluating whether elective transjugular intrahepatic portosystemic shunt placement improves outcomes in presumably 'non-high-risk' patients who are identified as being at increased risk of death.


Assuntos
Varizes Esofágicas e Gástricas , Derivação Portossistêmica Transjugular Intra-Hepática , Varizes , Adulto , Humanos , Varizes Esofágicas e Gástricas/complicações , Varizes Esofágicas e Gástricas/cirurgia , Varizes Esofágicas e Gástricas/tratamento farmacológico , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/prevenção & controle , Creatinina , Derivação Portossistêmica Transjugular Intra-Hepática/efeitos adversos , Varizes/complicações , Antagonistas Adrenérgicos beta/uso terapêutico , Cirrose Hepática/etiologia , Sódio
14.
J Cell Sci ; 135(7)2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35194638

RESUMO

Multicellular organisms use dedicator of cytokinesis (DOCK) family guanine nucleotide exchange factors (GEFs) to activate Rac/Rho-of-plants small GTPases and coordinate cell shape change. In developing tissues, DOCK signals integrate cell-cell interactions with cytoskeleton remodeling, and the GEFs cluster reversibly at specific organelle surfaces to orchestrate cytoskeletal reorganization. The domain organizations among DOCK orthologs are diverse, and the mechanisms of localization control are poorly understood. Here, we use combinations of transgene complementation and live-cell imaging assays to uncover an evolutionarily conserved and essential localization determinant in the DOCK-GEF named SPIKE1. The SPIKE1-DHR3 domain is sufficient for organelle association in vivo, and displays a complicated lipid-binding selectivity for both phospholipid head groups and fatty acid chain saturation. SPIKE1-DHR3 is predicted to adopt a C2-domain structure and functions as part of a tandem C2 array that enables reversible clustering at the cell apex. This work provides mechanistic insight into how DOCK GEFs sense compositional and biophysical membrane properties at the interface of two organelle systems.


Assuntos
Fatores de Troca do Nucleotídeo Guanina , Proteínas Monoméricas de Ligação ao GTP , Domínios C2 , Citocinese , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Organelas/metabolismo
15.
J Neuroinflammation ; 21(1): 49, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38355633

RESUMO

BACKGROUND: Myeloid-derived suppressor cells (MDSCs) constitute a recently discovered bone-marrow-derived cell type useful for dealing with neuroinflammatory disorders. However, these cells are only formed during inflammatory conditions from immature myeloid cells (IMCs) that acquire immunosuppressive activity, thus being commonly gathered from diseased animals. Then, to obtain a more clinically feasible source, we characterized IMCs directly derived from healthy bone marrow and proved their potential immunosuppressive activity under pathological conditions in vitro. We then explored their neuroprotective potential in a model of human cerebellar ataxia, the Purkinje Cell Degeneration (PCD) mouse, as it displays a well-defined neurodegenerative and neuroinflammatory process that can be also aggravated by invasive surgeries. METHODS: IMCs were obtained from healthy bone marrow and co-cultured with activated T cells. The proliferation and apoptotic rate of the later were analyzed with Tag-it Violet. For in vivo studies, IMCs were transplanted by stereotactic surgery into the cerebellum of PCD mice. We also used sham-operated animals as controls of the surgical effects, as well as their untreated counterparts. Motor behavior of mice was assessed by rotarod test. The Purkinje cell density was measured by immunohistochemistry and cell death assessed with the TUNEL technique. We also analyzed the microglial phenotype by immunofluorescence and the expression pattern of inflammation-related genes by qPCR. Parametric tests were applied depending on the specific experiment: one or two way ANOVA and Student's T test. RESULTS: IMCs were proven to effectively acquire immunosuppressive activity under pathological conditions in vitro, thus acting as MDSCs. Concerning in vivo studios, sham-operated PCD mice suffered detrimental effects in motor coordination, Purkinje cell survival and microglial activation. After intracranial administration of IMCs into the cerebellum of PCD mice, no special benefits were detected in the transplanted animals when compared to untreated mice. Nonetheless, this transplant almost completely prevented the impairments caused by the surgery in PCD mice, probably by the modulation of the inflammatory patterns. CONCLUSIONS: Our work comprise two main translational findings: (1) IMCs can be directly used as they behave as MDSCs under pathological conditions, thus avoiding their gathering from diseased subjects; (2) IMCs are promising adjuvants when performing neurosurgery.


Assuntos
Cerebelo , Células Mieloides , Camundongos , Humanos , Animais , Células Mieloides/metabolismo , Células de Purkinje/patologia , Monócitos , Imunossupressores
16.
Plant Biotechnol J ; 22(7): 1942-1956, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38379432

RESUMO

Advancement of DNA-synthesis technologies has greatly facilitated the development of synthetic biology tools. However, high-complexity DNA sequences containing tandems of short repeats are still notoriously difficult to produce synthetically, with commercial DNA synthesis companies usually rejecting orders that exceed specific sequence complexity thresholds. To overcome this limitation, we developed a simple, single-tube reaction method that enables the generation of DNA sequences containing multiple repetitive elements. Our strategy involves commercial synthesis and PCR amplification of padded sequences that contain the repeats of interest, along with random intervening sequence stuffers that include type IIS restriction enzyme sites. GoldenBraid molecular cloning technology is then employed to remove the stuffers, rejoin the repeats together in a predefined order, and subclone the tandem(s) in a vector using a single-tube digestion-ligation reaction. In our hands, this new approach is much simpler, more versatile and efficient than previously developed solutions to this problem. As a proof of concept, two different phytohormone-responsive, synthetic, repetitive proximal promoters were generated and tested in planta in the context of transcriptional reporters. Analysis of transgenic lines carrying the synthetic ethylene-responsive promoter 10x2EBS-S10 fused to the GUS reporter gene uncovered several developmentally regulated ethylene response maxima, indicating the utility of this reporter for monitoring the involvement of ethylene in a variety of physiologically relevant processes. These encouraging results suggest that this reporter system can be leveraged to investigate the ethylene response to biotic and abiotic factors with high spatial and temporal resolution.


Assuntos
Reguladores de Crescimento de Plantas , Regiões Promotoras Genéticas , Regiões Promotoras Genéticas/genética , Reguladores de Crescimento de Plantas/metabolismo , Biologia Sintética/métodos , Plantas Geneticamente Modificadas/genética , Clonagem Molecular/métodos , Regulação da Expressão Gênica de Plantas
17.
Mass Spectrom Rev ; 2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37597182

RESUMO

Epigenetic modifications are closely related to certain disorders of the organism, including the development of tumors. One of the main epigenetic modifications is the methylation of DNA cytosines, 5-methyl-2'-deoxycycytidine. Furthermore, 5-mdC can be oxidized to form three new modifications, 5-(hydroxymethyl)-2'-deoxycytidine, 5-formyl-2'-deoxycytidine, and 5-carboxy-2'-deoxycytidine. The coupling of liquid chromatography with tandem mass spectrometry has been widely used for the total determination of methylated DNA cytosines in samples of biological and clinical interest. These methods are based on the measurement of the free compounds (e.g., urine) or after complete hydrolysis of the DNA (e.g., tissues) followed by a preconcentration, derivatization, and/or clean-up step. This review highlights the main advances in the quantification of modified nucleotides and nucleosides by isotope dilution using isotopically labeled analogs combined with liquid or gas chromatography coupled to mass spectrometry reported in the last 20 years. The different possible sources of labeled compounds are indicated. Special emphasis has been placed on the different types of chromatography commonly used (reverse phase and hydrophilic interaction liquid chromatography) and the derivatization methods developed to enhance chromatographic resolution and ionization efficiency. We have also revised the application of bidimensional chromatography and indicated significant biological and clinical applications of these determinations.

18.
Phys Rev Lett ; 132(15): 156701, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38682975

RESUMO

A new perovskite KOsO_{3} has been stabilized under high-pressure and high-temperature conditions. It is cubic at 500 K (Pm-3m) and undergoes subsequent phase transitions to tetragonal at 320 K (P4/mmm) and rhombohedral (R-3m) at 230 K as shown from refining synchrotron x-ray powder diffraction (SXRD) data. The larger orbital overlap integral and the extended wave function of 5d electrons in the perovskite KOsO_{3} allow to explore physics from the regime where Mott and Hund's rule couplings dominate to the state where the multiple interactions are on equal footing. We demonstrate an exotic magnetic ordering phase found by neutron powder diffraction along with physical properties via a suite of measurements including magnetic and transport properties, differential scanning calorimetry, and specific heat, which provide comprehensive information for a system at the crossover from localized to itinerant electronic behavior.

19.
Exp Physiol ; 109(4): 600-613, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38230961

RESUMO

A positive relationship between local tissue temperature and perfusion exists, with isolated limb-segment hyperthermia stimulating hyperaemia in the heated region without affecting the adjacent, non-heated limb segment. However, whether partial-limb segment heating evokes a heightened tissue perfusion in the heated region without directly or reflexly affecting the non-heated tissues of the same limb segment remains unknown. This study investigated, in 11 healthy young adults, the lower limb temperature and haemodynamic responses to three levels of 1 h upper-leg heating, none of which alter core temperature: (1) whole-thigh (WTH; water-perfused garment), (2) quadriceps (QH; water-perfused garment) and (3) partial-quadriceps (PQH; pulsed shortwave diathermy) heating. It was hypothesised that perfusion would only increase in the heated regions. WTH, QH and PQH increased local heated tissue temperature by 2.9 ± 0.6, 2.0 ± 0.7 and 2.9 ± 1.3°C (P < 0.0001), respectively, whilst remaining unchanged in the non-heated hamstrings and quadriceps tissues during QH and PQH. WTH induced a two-fold increase in common femoral artery blood flow (P < 0.0001) whereas QH and PQH evoked a similar ∼1.4-fold elevation (P ≤ 0.0018). During QH and PQH, however, tissue oxygen saturation and laser-Doppler skin blood flow in the adjacent non-heated hamstrings or quadriceps tissues remained stable (P > 0.5000). These findings in healthy young humans demonstrate a tight thermo-haemodynamic coupling during regional thigh heating, providing further evidence of the importance of local heat-activated mechanisms on the control of blood circulation.


Assuntos
Hipertermia Induzida , Coxa da Perna , Adulto Jovem , Humanos , Calefação , Fluxo Sanguíneo Regional/fisiologia , Extremidade Inferior , Hemodinâmica , Temperatura Alta , Água
20.
Ann Hematol ; 103(2): 583-591, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37923805

RESUMO

Although it is known that increasing age is associated with increased morbidity and mortality in allogeneic transplantation (allo-HSCT), individualization of the process may allow to perform it in progressively older patients.This study analyzed the outcome of 97 patients older than 60 years with a first allo-HSCT performed at our institution between 2011 and 2019.Median age was 66 years (range 60-79) and 15.4% were older than 70 years. The most frequent diagnosis was acute leukemia (50.5%), and 58.8% received a myeloablative conditioning. With a median follow-up of 33.9 months (range 7.9-111.5), at 3-years overall survival (OS) was 50%; progression-free survival (PFS), 46%; cumulative incidence of relapse, 22%; and non-relapse mortality (NRM), 32%. There were no significant differences in OS (p = 0.415), PFS (p = 0.691), cumulative incidence of relapse (p = 0.357) or NRM (p = 0.658) between patients of 60-64 years (n = 37), 65-69 (n = 45) and ≥ 70 years (n = 15). No differences were observed either depending on the intensity of the conditioning regimen in terms of OS (p = 0.858), PFS (p = 0.729), cumulative incidence of relapse (p = 0.416) or NRM (p = 0.270).In conclusion, older adults can safely and effectively undergo allo-HSCT with proper patient selection and individualized transplantation procedures.


Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda , Humanos , Idoso , Pessoa de Meia-Idade , Estudos de Viabilidade , Estudos Retrospectivos , Leucemia Mieloide Aguda/complicações , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Recidiva , Condicionamento Pré-Transplante/métodos , Doença Enxerto-Hospedeiro/etiologia
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