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Errors in proteostasis, which requires regulated degradation and recycling of diverse proteins, are linked to aging, cancer and neurodegenerative disease (1). In particular, recycling proteins from multiprotein complexes, organelles and membranes is initiated by ubiquitylation, extraction and unfolding by the essential mechanoenzyme VCP (2-4), and ubiquitin removal by deubiquitinases (DUBs), a class of â¼100 ubiquitin-specific proteases in humans (5, 6). As VCP's substrate recognition requires ubiquitylation, the removal of ubiquitins from substrates for recycling must follow extraction and unfolding. How the activities of VCP and different DUBs are coordinated for protein recycling or other fates is unclear. Here, we employ a photochemistry-based approach to profile proteome-wide domain-specific VCP interactions in living cells (7). We identify DUBs that bind near the entry, exit, or both sites of VCP's central pore, the channel for ATP-dependent substrate translocation (8-10). From this set of DUBs, we focus on VCPIP1, required for organelle assembly and DNA repair (11-13), that our chemical proteomics workflow indicates binds the central pore's entry and exit sites. We determine a â¼3Å cryo-EM structure of the VCP-VCPIP1 complex and find up to 3 VCPIP1 protomers interact with the VCP hexamer. VCPIP1's UBX-L domain binds VCP's N-domain in a 'down' conformation, linked to VCP's ADP-bound state (2, 14), and the deubiquitinase domain is positioned at the central pore's exit site, poised to remove ubiquitin following substrate unfolding. We find that VCP stimulates VCPIP1's DUB activity and use mutagenesis and single-molecule mass photometry assays to test the structural model. Together, our data suggest that DUBs bind VCP at distinct sites and reveal how the two enzyme activities can be coordinated to achieve specific downstream outcomes for ubiquitylated proteins.
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Cells mechanically interface with their surroundings through cytoskeleton-linked adhesions, allowing them to sense physical cues that instruct development and drive diseases such as cancer. Contractile forces generated by myosin motor proteins mediate these mechanical signal transduction processes through unclear protein structural mechanisms. Here, we show that myosin forces elicit structural changes in actin filaments (F-actin) that modulate binding by the mechanosensitive adhesion protein α-catenin. Using correlative cryo-fluorescence microscopy and cryo-electron tomography, we identify F-actin featuring domains of nanoscale oscillating curvature at cytoskeleton-adhesion interfaces enriched in zyxin, a marker of actin-myosin generated traction forces. We next introduce a reconstitution system for visualizing F-actin in the presence of myosin forces with cryo-electron microscopy, which reveals morphologically similar superhelical F-actin spirals. In simulations, transient forces mimicking tugging and release of filaments by motors produce spirals, supporting a mechanistic link to myosin's ATPase mechanochemical cycle. Three-dimensional reconstruction of spirals uncovers extensive asymmetric remodeling of F-actin's helical lattice. This is recognized by α-catenin, which cooperatively binds along individual strands, preferentially engaging interfaces featuring extended inter-subunit distances while simultaneously suppressing rotational deviations to regularize the lattice. Collectively, we find that myosin forces can deform F-actin, generating a conformational landscape that is detected and reciprocally modulated by a mechanosensitive protein, providing a direct structural glimpse at active force transduction through the cytoskeleton.
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OBJECTIVES: In November 2019, the Massachusetts legislature passed An Act Modernizing Tobacco Control and became the first state to restrict retail sales of all flavored (including menthol) cigarettes, e-cigarettes, and other tobacco products (the Act). Additional tobacco control policies and health insurance coverage for tobacco treatment were included as part of the Act. Implementation of these policies occurred between November 2019 and June 2020. This study explored challenges and facilitators during the implementation of the Act experienced by public health officials, school personnel, and healthcare providers. METHODS: We conducted in-depth interviews with a purposive sample of 9 public health officials and advocates, 9 school personnel, and 8 healthcare providers from March to December 2021. We conducted thematic analysis of interview transcripts using inductive codes of key themes emerging from the interviews. RESULTS: Interviewees highlighted three key themes that impacted the implementation of the Act: 1) Education of those impacted by the Act, 2) Organizational-level changes to incorporate the Act, and 3) Enforcement challenges. Examples of challenges to the implementation of the Act included COVID-19 pandemic restrictions, navigating tobacco industry tactics around naming flavors, and confusion regarding health insurance coverage for tobacco use cessation programs. Examples of facilitators were enforcement leading to retailer compliance, committed advocacy efforts of leadership/champions, and strong coordination within and between organizations. CONCLUSIONS: These findings of Massachusetts's experience in policy implementation can inform the preparation to implement similar tobacco control policies in other states.
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Comércio , Aromatizantes , Produtos do Tabaco , Humanos , Massachusetts , Produtos do Tabaco/economia , Produtos do Tabaco/legislação & jurisprudência , Indústria do Tabaco/legislação & jurisprudência , COVID-19/epidemiologia , COVID-19/prevenção & controle , Sistemas Eletrônicos de Liberação de Nicotina , Saúde Pública , Pessoal de SaúdeRESUMO
BACKGROUND: In November 2019, the Massachusetts legislature passed An Act Modernizing Tobacco Control and became the first state to restrict retail sales of all flavored (including menthol) cigarettes, e-cigarettes, and other tobacco products. Our study aims to provide the retailer experience of the new law from the perspectives of multiple stakeholders, including tobacco retailers themselves, public health officials, and Massachusetts residents. METHODS: We conducted in-depth interviews with seven tobacco retailers and ten public health officials from March 2021 to April 2022. Monthly repeated cross-sectional surveys were administered through the online survey panel Prodege from April 2021 to August 2022 (adult sample: N = 765; adolescent sample: N = 900). Themes from interviews were identified by drawing on deductive codes informed by the interview guide, followed by inductive coding of data. Survey data were descriptively analyzed in R. RESULTS: Key themes included retailer frustration over loss of sales to neighboring states, factors associated with retailer compliance, and the need for increased education regarding the law. Survey results showed that a minority of adolescents (13.3%) and adults (26.1%) who vaped in the past 30-days were traveling to border states to purchase vape products. Less than one-quarter of adolescent participants and less than half of adult participants could correctly identify which products Massachusetts did not sell. CONCLUSIONS: Evidence from the retailer, public health, and end-user perspectives support mutual benefits of adjacent states enacting flavored tobacco sales restrictions, improved policy education for retailers and the public, and improved retailer enforcement.
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Comércio , Produtos do Tabaco , Humanos , Massachusetts , Produtos do Tabaco/legislação & jurisprudência , Produtos do Tabaco/economia , Adolescente , Comércio/legislação & jurisprudência , Adulto , Masculino , Feminino , Estudos Transversais , Adulto Jovem , Sistemas Eletrônicos de Liberação de Nicotina , Pessoa de Meia-Idade , Saúde Pública , Controle do TabagismoRESUMO
INTRODUCTION: The Massachusetts legislature passed An Act Modernizing Tobacco Control in November 2019 to restrict retail sales of flavored commercially manufactured tobacco products including menthol products, increase penalties for violating the law's provisions, and provide health insurance coverage for tobacco treatment. AIMS AND METHODS: This study explores key informants' perceptions of intended and unintended impacts of implementation of the 2019 Massachusetts statewide law through a health equity and racial justice lens. We conducted in-depth interviews with 25 key informants from three key informant groups (public health officials and advocates, clinicians, and school staff) between March 2021 and April 2022. Using deductive codes on unintended impacts of the implementation of the law's policies, we conducted a focused analysis to identify impacts that were perceived and observed by informants from different key informant groups. RESULTS: Perceived or observed impacts of the law were identified across multiple levels by key informants and included concerns related to three broad themes: 1) intended impacts on health equity and racial justice, 2) ongoing availability of restricted products undermining the intended impact of the law, and 3) inequitable targeting by the policies and enforcement among communities of color. CONCLUSIONS: Future evaluation is needed to assess the intended and unintended impacts of implementation of the Massachusetts law to maximize the potential of the policies to reduce tobacco-related health disparities. We discuss implications and recommendations for achieving a national policy and equitable enforcement of flavored tobacco sales restrictions. IMPLICATIONS: This qualitative study among 25 key informants including public health and tobacco control advocates, clinicians, and school staff obtained perspectives of intended and unintended health equity and racial justice impacts of the 2019 Massachusetts An Act Modernizing Tobacco Control. Findings and recommendations from this study can inform monitoring efforts to assess the law's impacts in Massachusetts and the adoption of similar flavored tobacco sales restrictions and other tobacco control policies in other states to maximize the health equity benefits and minimize unintended impacts.
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Equidade em Saúde , Produtos do Tabaco , Massachusetts , Humanos , Produtos do Tabaco/legislação & jurisprudência , Justiça Social , Saúde Pública/legislação & jurisprudência , Controle do TabagismoRESUMO
Radiation-use efficiency (RUE) is an important trait for raising biomass and yield potential in plant breeding. However, the effect of the planting system (PS) on genetic variation in RUE has not been previously investigated. Our objectives were to quantify genetic variation in RUE, biomass and grain yield in raised-bed and flat-basin planting systems, and associations with canopy-architecture traits (flag-leaf angle and curvature). Twelve spring wheat (Triticum aestivum L.) cultivars were evaluated under irrigated conditions for 3 years in North West Mexico using raised-bed and flat-basin planting systems. Canopy architecture traits were measured at booting and anthesis + 7 days. Grain yield (10.6%), biomass (7.6%), and pre-grain-filling RUE (9.7%) were higher in raised beds than flat basins, while a significant planting system × genotype interaction was found for grain yield. Genetic variation in pre-grain-filling RUE was associated with biomass and grain yield in beds and basins. In flat basins, higher pre-grain-filling RUE was correlated with a more upright flag-leaf angle but not in raised beds. In raised beds, cultivars with less upright flag-leaf angle had greater fractional light interception pre-anthesis. Taller semi-dwarf cultivars intercepted relatively more radiation in the beds than the flats before anthesis, consistent with the taller cultivars showing relatively greater increases in yield in beds compared to flats. Our results indicated that the evaluation of genotypes for RUE and biomass in wheat breeding should take into account planting systems to capture genotype × PS effects. In addition, the results demonstrate how flag-leaf angle has a different effect depending on the planting system.
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Fascin crosslinks actin filaments (F-actin) into bundles that support tubular membrane protrusions including filopodia and stereocilia. Fascin dysregulation drives aberrant cell migration during metastasis, and fascin inhibitors are under development as cancer therapeutics. Here, we use cryo-electron microscopy, cryo-electron tomography coupled with custom denoising, and computational modeling to probe fascin's F-actin crosslinking mechanisms across spatial scales. Our fascin crossbridge structure reveals an asymmetric F-actin binding conformation that is allosterically blocked by the inhibitor G2. Reconstructions of seven-filament hexagonal bundle elements, variability analysis, and simulations show how structural plasticity enables fascin to bridge varied inter-filament orientations, accommodating mismatches between F-actin's helical symmetry and bundle hexagonal packing. Tomography of many-filament bundles and modeling uncovers geometric rules underlying emergent fascin binding patterns, as well as the accumulation of unfavorable crosslinks that limit bundle size. Collectively, this work shows how fascin harnesses fine-tuned nanoscale structural dynamics to build and regulate micron-scale F-actin bundles.
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BACKGROUND: The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2-Is) on recurrent atrial fibrillation (AF) among patients undergoing catheter ablation is not well described. OBJECTIVES: This study sought to assess the impact of SGLT2-Is on the recurrence of AF among patients with type 2 diabetes mellitus (DM) after catheter ablation. METHODS: Using the TriNetX research network, we identified, by means of Current Procedural Terminology codes, patients ≥18 years of age with type 2 diabetes mellitus (DM) who had undergone AF ablation from April 1, 2014, to November 30, 2021. Patients were stratified based on the baseline SGLT2-I use. Propensity-score matching resulted in 2,225 patients in each cohort. The primary outcome was a composite of cardioversion, new antiarrhythmic drug (AAD) therapy, or re-do AF ablation after a blanking period after the index ablation. Additional outcomes included heart failure exacerbations, ischemic stroke, all-cause hospitalization, and death during 12 months of follow-up. RESULTS: SGLT2-I use in patients with type 2 DM undergoing AF ablation was associated with a significantly lower risk of cardioversion, new AAD therapy, and re-do AF ablation (adjusted OR: 0.68; 95% CI: 0.602-0.776; P < 0.0001). At 12 months, patients on SGLT2-Is had a higher probability of event-free survival (HR: 0.85, 95% CI: 0.77-0.95; log-rank test chi-square = 8.7; P = 0.003). All secondary outcomes were lower in the SGLT2I group; however, the ischemic stroke did not differ between groups. CONCLUSIONS: Use of SGLT2-Is in patients with type 2 DM is associated with a lower risk of arrhythmia recurrence after AF ablation and thence a reduced need for cardioversion, AAD therapy, or re-do AF ablation.
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Fibrilação Atrial , Ablação por Cateter , Diabetes Mellitus Tipo 2 , AVC Isquêmico , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/cirurgia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Transportador 2 de Glucose-Sódio/uso terapêutico , Resultado do Tratamento , Recidiva Local de Neoplasia/etiologia , Antiarrítmicos/uso terapêutico , Ablação por Cateter/métodos , AVC Isquêmico/tratamento farmacológico , AVC Isquêmico/etiologia , AVC Isquêmico/cirurgiaRESUMO
We assessed vaping behaviors, environments, COVID-19 influences, and barriers and facilitators of existing approaches that address adolescent vaping in Massachusetts middle and high schools. Findings from this study will provide considerations for individual schools or districts as they advance adolescent vaping prevention and treatment efforts. We analyzed 310 open-ended comments from Massachusetts school administrators who completed a survey between November 2020 and January 2021. Further, we analyzed nine semi-structured interviews with administrators (e.g., principals, vice principals, school nurses) from Massachusetts school systems (n = 6) and school-based anti-tobacco advocates (n = 3); interviews took place between May and December 2021. Informed by Green's PRECEDE model, we conducted a framework analysis using deductive codes based on the model constructs (enabling, reinforcing, and predisposing factors) and inductive codes of key themes emerging from the interviews. Challenges to addressing adolescent vaping included staff capacity, funding, and lack of mental health and counseling supports. The COVID-19 pandemic was a major barrier to conducting usual in-person vaping programs, but also reduced student vaping at school due to new social distancing practices and bathroom use policies. Facilitators of vaping interventions included peer-led initiatives and parental involvement. Participants discussed the importance of educating adolescents on the harms of vaping and the move toward alternatives-to-suspension programs rather than disciplinary action. School-based anti-vaping program implementers-such as school districts, state departments of education, or local health departments-will need to leverage facilitators such as peer-led initiatives, alternatives-to-suspension approaches, and parental involvement, to increase the potential impact of these programs.
The purpose of this study was to understand challenges that school administrators faced in their approaches to address adolescent vaping in Massachusetts middle and high schools. We analyzed open-ended comments from Massachusetts school administrators who completed a survey between November 2020 and January 2021. Further, we analyzed nine interviews with administrators (e.g., principals, vice principals, school nurses) from Massachusetts school systems (n = 6) and school-based anti-tobacco advocates (n = 3); interviews took place between May and December 2021. We found that challenges to addressing adolescent vaping included school personnel capacity, funding, and lack of mental health and counseling supports. The COVID-19 pandemic was a major barrier to conducting usual in-person vaping programs, but also reduced student vaping at school due to new social distancing practices and bathroom use policies. Successful approaches included peer-led initiatives and parental involvement, and participants discussed the importance of educating adolescents on the harms of vaping. Based on our findings, school-based anti-vaping program practitionerssuch as school districts, state departments of education, or local health departmentsshould leverage peer-led initiatives, alternatives-to-suspension approaches, and parental involvement, to increase the potential impact of adolescent vaping prevention and treatment efforts.
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COVID-19 , Pandemias , Adolescente , Humanos , Pandemias/prevenção & controle , COVID-19/prevenção & controle , Instituições Acadêmicas , Massachusetts/epidemiologia , Estudantes/psicologiaRESUMO
BACKGROUND: Insertable cardiac monitors (ICMs) are a clinically effective means of detecting atrial fibrillation (AF) in high-risk patients, and guiding the initiation of non-vitamin K oral anticoagulants (NOACs). Their cost-effectiveness from a US clinical payer perspective is not yet known. The objective of this study was to evaluate the cost-effectiveness of ICMs compared to standard of care (SoC) for detecting AF in patients at high risk of stroke (CHADS2 ≥ 2), in the US. METHODS: Using patient data from the REVEAL AF trial (n = 393, average CHADS2 score = 2.9), a Markov model estimated the lifetime costs and benefits of detecting AF with an ICM or with SoC (specifically intermittent use of electrocardiograms and 24-h Holter monitors). Ischemic and hemorrhagic strokes, intra- and extra-cranial hemorrhages, and minor bleeds were modelled. Diagnostic and device costs, costs of treating stroke and bleeding events and medical therapy-specifically costs of NOACs were included. Costs and health outcomes, measured as quality-adjusted life years (QALYs), were discounted at 3% per annum, in line with standard practice in the US setting. One-way deterministic and probabilistic sensitivity analyses (PSA) were undertaken. RESULTS: Lifetime per-patient cost for ICM was $31,116 versus $25,330 for SoC. ICMs generated a total of 7.75 QALYs versus 7.59 for SoC, with 34 fewer strokes projected per 1000 patients. The model estimates a number needed to treat of 29 per stroke avoided. The incremental cost-effectiveness ratio was $35,528 per QALY gained. ICMs were cost-effective in 75% of PSA simulations, using a $50,000 per QALY threshold, and a 100% probability of being cost-effective at a WTP threshold of $150,000 per QALY. CONCLUSIONS: The use of ICMs to identify AF in a high-risk population is likely to be cost-effective in the US healthcare setting.
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Fibrilação Atrial , Humanos , Administração Oral , Anticoagulantes/administração & dosagem , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/tratamento farmacológico , Análise Custo-Benefício , Hemorragia , Anos de Vida Ajustados por Qualidade de Vida , Acidente Vascular Cerebral , Ensaios Clínicos como AssuntoRESUMO
BACKGROUND: Data examining associations among social support, survival, and healthcare utilization are lacking in patients with advanced cancer. METHODS: We conducted a cross-sectional secondary analysis using data from a prospective longitudinal cohort study of 966 hospitalized patients with advanced cancer at Massachusetts General Hospital from 2014 through 2017. We used NLP to identify extent of patients' social support (limited versus adequate as defined by NLP-aided review of the Electronic Health Record (EHR)). Two independent coders achieved a Kappa of 0.90 (95% CI: 0.84-1.00) using NLP. Using multivariable regression models, we examined associations of social support with: 1) OS; 2) death or readmission within 90 days of hospital discharge; 3) time to readmission within 90 days; and 4) hospital length of stay (LOS). RESULTS: Patients' median age was 65 (range: 21-92) years, and a plurality had gastrointestinal (GI) cancer (34.3%) followed by lung cancer (19.5%). 6.2% (60/966) of patients had limited social support. In multivariable analyses, limited social support was not significantly associated with OS (HR = 1.13, P = 0.390), death or readmission (OR = 1.18, P = 0.578), time to readmission (HR = 0.92, P = 0.698), or LOS (ß = -0.22, P = 0.726). We identified a potential interaction suggesting cancer type (GI cancer versus other) may be an effect modifier of the relationship between social support and OS (interaction term P = 0.053). In separate unadjusted analyses, limited social support was associated with lower OS (HR = 2.10, P = 0.008) in patients with GI cancer but not other cancer types (HR = 1.00, P = 0.991). CONCLUSION: We used NLP to assess the extent of social support in patients with advanced cancer. We did not identify significant associations of social support with OS or healthcare utilization but found cancer type may be an effect modifier of the relationship between social support and OS. These findings underscore the potential utility of NLP for evaluating social support in patients with advanced cancer.
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Processamento de Linguagem Natural , Neoplasias , Humanos , Idoso , Estudos Longitudinais , Estudos Prospectivos , Estudos Transversais , Neoplasias/terapiaRESUMO
The rate with which crop yields per hectare increase each year is plateauing at the same time that human population growth and other factors increase food demand. Increasing yield potential ( Y p ) of crops is vital to address these challenges. In this review, we explore a component of Y p that has yet to be optimised - that being improvements in the efficiency with which light energy is converted into biomass ( ε c ) via modifications to CO2 fixed per unit quantum of light (α), efficiency of respiratory ATP production ( ε prod ) and efficiency of ATP use ( ε use ). For α, targets include changes in photoprotective machinery, ribulose bisphosphate carboxylase/oxygenase kinetics and photorespiratory pathways. There is also potential for ε prod to be increased via targeted changes to the expression of the alternative oxidase and mitochondrial uncoupling pathways. Similarly, there are possibilities to improve ε use via changes to the ATP costs of phloem loading, nutrient uptake, futile cycles and/or protein/membrane turnover. Recently developed high-throughput measurements of respiration can serve as a proxy for the cumulative energy cost of these processes. There are thus exciting opportunities to use our growing knowledge of factors influencing the efficiency of photosynthesis and respiration to create a step-change in yield potential of globally important crops.
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Dióxido de Carbono , Produtos Agrícolas , Citocromo P-450 CYP2B1 , Trifosfato de Adenosina/metabolismo , Dióxido de Carbono/metabolismo , Produtos Agrícolas/fisiologia , Citocromo P-450 CYP2B1/metabolismo , Fotossíntese , Ribulose-Bifosfato Carboxilase/metabolismoRESUMO
Vaccine strategies aimed at eliciting human immunodeficiency virus (HIV)-specific CD8+ T cells are one major target of interest in HIV functional cure strategies. We hypothesized that CD8+ T cells elicited by therapeutic vaccination during antiretroviral therapy (ART) would be recalled and boosted by treatment with the interleukin 15 (IL-15) superagonist N-803 after ART discontinuation. We intravenously immunized four simian immunodeficiency virus-positive (SIV+) Mauritian cynomolgus macaques receiving ART with vesicular stomatitis virus (VSV), modified vaccinia virus Ankara strain (MVA), and recombinant adenovirus serotype 5 (rAd-5) vectors all expressing SIVmac239 Gag. Immediately after ART cessation, these animals received three doses of N-803. Four control animals received no vaccines or N-803. The vaccine regimen generated a high-magnitude response involving Gag-specific CD8+ T cells that were proliferative and biased toward an effector memory phenotype. We then compared cells elicited by vaccination (Gag specific) to cells elicited by SIV infection and unaffected by vaccination (Nef specific). We found that N-803 treatment enhanced the frequencies of both bulk and proliferating antigen-specific CD8+ T cells elicited by vaccination and the antigen-specific CD8+ T cells elicited by SIV infection. In sum, we demonstrate that a therapeutic heterologous prime-boost-boost (HPBB) vaccine can elicit antigen-specific effector memory CD8+ T cells that are boosted by N-803. IMPORTANCE While antiretroviral therapy (ART) can suppress HIV replication, it is not a cure. It is therefore essential to develop therapeutic strategies to enhance the immune system to better become activated and recognize virus-infected cells. Here, we evaluated a novel therapeutic vaccination strategy delivered to SIV+ Mauritian cynomolgus macaques receiving ART. ART was then discontinued and we delivered an immunotherapeutic agent (N-803) after ART withdrawal with the goal of eliciting and boosting anti-SIV cellular immunity. Immunologic and virologic analysis of peripheral blood and lymph nodes collected from these animals revealed transient boosts in the frequency, activation, proliferation, and memory phenotype of CD4+ and CD8+ T cells following each intervention. Overall, these results are important in educating the field of the transient nature of the immunological responses to this particular therapeutic regimen and the similar effects of N-803 on boosting T cells elicited by vaccination or elicited naturally by infection.
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Linfócitos T CD8-Positivos , Vacinas contra a SAIDS , Síndrome de Imunodeficiência Adquirida dos Símios , Vírus da Imunodeficiência Símia , Animais , Proliferação de Células , Macaca mulatta/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vacinação , Vaccinia virusRESUMO
ATP-hydrolysis-coupled actin polymerization is a fundamental mechanism of cellular force generation1-3. In turn, force4,5 and actin filament (F-actin) nucleotide state6 regulate actin dynamics by tuning F-actin's engagement of actin-binding proteins through mechanisms that are unclear. Here we show that the nucleotide state of actin modulates F-actin structural transitions evoked by bending forces. Cryo-electron microscopy structures of ADP-F-actin and ADP-Pi-F-actin with sufficient resolution to visualize bound solvent reveal intersubunit interfaces bridged by water molecules that could mediate filament lattice flexibility. Despite extensive ordered solvent differences in the nucleotide cleft, these structures feature nearly identical lattices and essentially indistinguishable protein backbone conformations that are unlikely to be discriminable by actin-binding proteins. We next introduce a machine-learning-enabled pipeline for reconstructing bent filaments, enabling us to visualize both continuous structural variability and side-chain-level detail. Bent F-actin structures reveal rearrangements at intersubunit interfaces characterized by substantial alterations of helical twist and deformations in individual protomers, transitions that are distinct in ADP-F-actin and ADP-Pi-F-actin. This suggests that phosphate rigidifies actin subunits to alter the bending structural landscape of F-actin. As bending forces evoke nucleotide-state dependent conformational transitions of sufficient magnitude to be detected by actin-binding proteins, we propose that actin nucleotide state can serve as a co-regulator of F-actin mechanical regulation.
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Citoesqueleto de Actina , Actinas , Difosfato de Adenosina , Microscopia Crioeletrônica , Citoesqueleto de Actina/química , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/ultraestrutura , Actinas/química , Actinas/metabolismo , Actinas/ultraestrutura , Difosfato de Adenosina/química , Difosfato de Adenosina/metabolismo , Proteínas dos Microfilamentos/metabolismo , Solventes , Aprendizado de Máquina , Conformação ProteicaRESUMO
BACKGROUND: Patients with acute myeloid leukemia (AML) face an abrupt life-threatening illness and experience immense physical and psychological symptoms. However, no data describe how patients with AML cope longitudinally with their illness or the relationship between longitudinal coping and outcomes. METHODS: We conducted a secondary analysis of longitudinal data from 160 patients with high-risk AML enrolled in a supportive care intervention trial to describe coping strategies longitudinally across the illness course. We used the Brief COPE questionnaire, the Hospital Anxiety and Depression Scale, the Post-Traumatic Stress Disorder (PTSD) Checklist-Civilian Version, and the Functional Assessment of Cancer Therapy-Leukemia to measure coping strategies, psychological distress, and quality of life (QoL) at baseline and at weeks 2, 4, 12, and 24 after diagnosis. Electronic health records were used to assess healthcare utilization and end-of-life (EoL) outcomes, and multivariate analyses were used to assess the relationship between coping and outcomes. RESULTS: Longitudinal utilization of approach-oriented coping strategies was significantly associated with less distress (anxiety: ß, -0.18; P<.001; depression symptoms: ß, -0.42; P<.001; PTSD symptoms: ß, -0.60; P<.001) and better QoL (ß, 2.00; P<.001). Longitudinal utilization of avoidant coping strategies was significantly associated with greater distress (anxiety: ß, 0.64; depression symptoms: ß, 0.54; PTSD symptoms: ß, 2.13; P<.001 for all) and worse QoL (ß, -4.27; P<.001). Although the use of approach-oriented and avoidant coping strategies was not significantly associated with hospitalization, chemotherapy administration, or hospice use in the last 30 days of life, approach-oriented coping was associated with lower odds of ICU admissions (odds ratio, 0.92; P=.049). CONCLUSIONS: Longitudinal use of approach-oriented coping strategies was associated with less psychological distress, better QoL, and a lower likelihood of ICU admission, suggesting a possible target for supportive oncology interventions. Coping strategies did not impact EoL outcomes, and further research is needed to elucidate which patient factors impact EoL decision-making.
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Leucemia Mieloide Aguda , Qualidade de Vida , Humanos , Adaptação Psicológica , Ansiedade/psicologia , Depressão , Leucemia Mieloide Aguda/terapia , Qualidade de Vida/psicologia , Ensaios Clínicos como AssuntoRESUMO
Nonhuman primates (NHPs) are well-established basic and translational research models for human immunodeficiency virus (HIV) infections and pathophysiology, hematopoietic stem cell (HSC) transplantation, and assisted reproductive technologies. Recent advances in CRISPR/Cas9 gene editing technologies present opportunities to refine NHP HIV models for investigating genetic factors that affect HIV replication and designing cellular therapies that exploit genetic barriers to HIV infections, including engineering mutations into CCR5 and conferring resistance to HIV/simian immunodeficiency virus (SIV) infections. In this report, we provide an overview of recent advances and challenges in gene editing NHP embryos and discuss the value of genetically engineered animal models for developing novel stem cell-based therapies for curing HIV.
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Edição de Genes , Infecções por HIV , Animais , Sistemas CRISPR-Cas , Humanos , Primatas , Células-TroncoRESUMO
Wheat (Triticum aestivum L.) radiation use efficiency (RUE) must be raised through crop breeding to further increase the yield potential, as the harvest index is now close to its theoretical limit. Field experiments including 209 wheat cultivars which have been widely cultivated in China since the 1940s were conducted in two growing seasons (2018-2019 and 2019-2020) to evaluate the variations of phenological, physiological, plant architectural, and yield-related traits and their contributions to RUE and to identify limiting factors for wheat yield potential. The average annual genetic gain in grain yield was 0.60% (or 45.32 kg ha-1 year-1 ; R2 = 0.44, P < 0.01), mainly attributed to the gain in RUE (r = 0.85, P < 0.01). The net photosynthetic rates were positively and closely correlated with grain RUE and grain yield, suggesting source as a limiting factor to future yield gains. Thirty-four cultivars were identified, exhibiting not only high RUE, but also traits contributing to high RUE and 11 other critical traits - of known genetic basis - as potential parents for breeding to improve yield and RUE. Our findings reveal wheat traits and the associated loci conferring RUE, which are valuable for facilitating marker-assisted breeding to improve wheat RUE and yield potential.
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Melhoramento Vegetal , Triticum , Triticum/genética , Fenótipo , Grão Comestível/genética , Fotossíntese/genéticaRESUMO
Recent technological advances in next-generation sequencing (NGS) technologies have dramatically reduced the cost of DNA sequencing, allowing species with large and complex genomes to be sequenced. Although bread wheat (Triticum aestivum L.) is one of the world's most important food crops, efficient exploitation of molecular marker-assisted breeding approaches has lagged behind that achieved in other crop species, due to its large polyploid genome. However, an international public-private effort spanning 9 years reported over 65% draft genome of bread wheat in 2014, and finally, after more than a decade culminated in the release of a gold-standard, fully annotated reference wheat-genome assembly in 2018. Shortly thereafter, in 2020, the genome of assemblies of additional 15 global wheat accessions was released. As a result, wheat has now entered into the pan-genomic era, where basic resources can be efficiently exploited. Wheat genotyping with a few hundred markers has been replaced by genotyping arrays, capable of characterizing hundreds of wheat lines, using thousands of markers, providing fast, relatively inexpensive, and reliable data for exploitation in wheat breeding. These advances have opened up new opportunities for marker-assisted selection (MAS) and genomic selection (GS) in wheat. Herein, we review the advances and perspectives in wheat genetics and genomics, with a focus on key traits, including grain yield, yield-related traits, end-use quality, and resistance to biotic and abiotic stresses. We also focus on reported candidate genes cloned and linked to traits of interest. Furthermore, we report on the improvement in the aforementioned quantitative traits, through the use of (i) clustered regularly interspaced short-palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated gene-editing and (ii) positional cloning methods, and of genomic selection. Finally, we examine the utilization of genomics for the next-generation wheat breeding, providing a practical example of using in silico bioinformatics tools that are based on the wheat reference-genome sequence.
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The motor protein myosin-15 is necessary for the development and maintenance of mechanosensory stereocilia, and mutations in myosin-15 cause hereditary deafness. In addition to transporting actin regulatory machinery to stereocilia tips, myosin-15 directly nucleates actin filament ("F-actin") assembly, which is disrupted by a progressive hearing loss mutation (p.D1647G, "jordan"). Here, we present cryo-electron microscopy structures of myosin-15 bound to F-actin, providing a framework for interpreting the impacts of deafness mutations on motor activity and actin nucleation. Rigor myosin-15 evokes conformational changes in F-actin yet maintains flexibility in actin's D-loop, which mediates inter-subunit contacts, while the jordan mutant locks the D-loop in a single conformation. Adenosine diphosphate-bound myosin-15 also locks the D-loop, which correspondingly blunts actin-polymerization stimulation. We propose myosin-15 enhances polymerization by bridging actin protomers, regulating nucleation efficiency by modulating actin's structural plasticity in a myosin nucleotide state-dependent manner. This tunable regulation of actin polymerization could be harnessed to precisely control stereocilium height.
RESUMO
Allogeneic hematopoietic stem cell transplants (allo-HSCTs) dramatically reduce HIV reservoirs in antiretroviral therapy (ART) suppressed individuals. However, the mechanism(s) responsible for these post-transplant viral reservoir declines are not fully understood. Therefore, we modeled allo-HSCT in ART-suppressed simian-human immunodeficiency virus (SHIV)-infected Mauritian cynomolgus macaques (MCMs) to illuminate factors contributing to transplant-induced viral reservoir decay. Thus, we infected four MCMs with CCR5-tropic SHIV162P3 and started them on ART 6-16 weeks post-infection (p.i.), maintaining continuous ART during myeloablative conditioning. To prevent graft-versus-host disease (GvHD), we transplanted allogeneic MHC-matched α/ß T cell-depleted bone marrow cells and prophylactically treated the MCMs with cyclophosphamide and tacrolimus. The transplants produced ~ 85% whole blood donor chimerism without causing high-grade GvHD. Consequently, three MCMs had undetectable SHIV DNA in their blood post-transplant. However, SHIV-harboring cells persisted in various tissues, with detectable viral DNA in lymph nodes and tissues between 38 and 62 days post-transplant. Further, removing one MCM from ART at 63 days post-transplant resulted in SHIV rapidly rebounding within 7 days of treatment withdrawal. In conclusion, transplanting SHIV-infected MCMs with allogeneic MHC-matched α/ß T cell-depleted bone marrow cells prevented high-grade GvHD and decreased SHIV-harboring cells in the blood post-transplant but did not eliminate viral reservoirs in tissues.