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Synthetic biology uses living cells as molecular foundries for the biosynthesis of drugs, therapeutic proteins, and other commodities. However, the need for specialized equipment and refrigeration for production and distribution poses a challenge for the delivery of these technologies to the field and to low-resource areas. Here, we present a portable platform that provides the means for on-site, on-demand manufacturing of therapeutics and biomolecules. This flexible system is based on reaction pellets composed of freeze-dried, cell-free transcription and translation machinery, which can be easily hydrated and utilized for biosynthesis through the addition of DNA encoding the desired output. We demonstrate this approach with the manufacture and functional validation of antimicrobial peptides and vaccines and present combinatorial methods for the production of antibody conjugates and small molecules. This synthetic biology platform resolves important practical limitations in the production and distribution of therapeutics and molecular tools, both to the developed and developing world.
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Formação de Anticorpos , Peptídeos Catiônicos Antimicrobianos/biossíntese , Vacinas/biossíntese , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Sistema Livre de Células , Técnicas de Química Combinatória , Humanos , Biossíntese de Proteínas , Biologia Sintética , Transcrição Gênica , Vacinas/genéticaRESUMO
OBJECTIVES: Early pelvic binder placement in the field stabilizes pelvic fractures and tamponades potential hemorrhage within the pelvis. Despite known risk factors for pelvic fracture, it remains challenging to quickly triage and correctly apply a pelvic binder. We aim to develop a prediction model that exclusively uses prehospital criteria to inform the decision to place a pelvic binder. METHODS: The trauma registry was used to identify all trauma patients admitted to an urban Level I trauma center between January 2013 and December 2017. Variables collected included patient demographics, mechanism of injury, prehospital vital signs, and the presence of a pelvic fracture. Participants were randomly assigned to a training group (70%) or a validation group (30%). Univariate analyses were used to identify significant predictors for use in multivariate predictive models. RESULTS: A total of 8,480 (65% male; median age 49; median ISS 9) and 3,676 (65% male; median age 48; median ISS 9) trauma patients were randomly assigned to the training and validation groups, respectively. Univariate analysis showed significant likelihood of pelvic fracture associated with female sex, hemodynamic instability (initial systolic blood pressure < 90 mmHg), blunt injury type, specific mechanisms of injury (motor vehicle collision, motorcycle collision, pedestrian struck by motor vehicle, crushing injury, and riding an animal), impact location, and position in vehicle. Multivariate models adjusting for blunt type injury, hemodynamic instability, impact location, and position in vehicle showed that presence of two or more of these risk factors is significantly associated with presence of pelvic fracture. CONCLUSION: Establishing select prehospital criteria for the empiric application of pelvic binders for patients in the field with blunt injuries, hemodynamic instability, frontal or side motor vehicle collision impact, and non-front seat passenger may improve outcomes among patients with pelvic fractures.
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Serviços Médicos de Emergência , Fraturas Ósseas , Ossos Pélvicos , Doenças Vasculares , Ferimentos não Penetrantes , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Estudos Retrospectivos , Ossos Pélvicos/lesões , Escala de Gravidade do FerimentoRESUMO
Morphological traits suggesting powerful jumping abilities are characteristic of early crown primate fossils. Because tree squirrels lack certain 'primatelike' grasping features but frequently travel on the narrow terminal branches of trees, they make a viable extant model for an early stage of primate evolution. Here, we explore biomechanical determinants of jumping performance in the arboreal Eastern gray squirrel (Sciurus carolinensis, n = 3) as a greater understanding of the biomechanical strategies that squirrels use to modulate jumping performance could inform theories of selection for increased jumping ability during early primate evolution. We assessed vertical jumping performance by using instrumented force platforms upon which were mounted launching supports of various sizes, allowing us to test the influence of substrate diameter on jumping kinetics and performance. We used standard ergometric methods to quantify jumping parameters (e.g., takeoff velocity, total displacement, peak mechanical power) from force platform data during push-off. We found that tree squirrels display divergent mechanical strategies according to the type of substrate, prioritizing force production on flat ground versus center of mass displacement on narrower poles. As jumping represents a significant part of the locomotor behavior of most primates, we suggest that jumping from small arboreal substrates may have acted as a potential driver of the selection for elongated hindlimb segments in primates, allowing the center of mass to be accelerated over a longer distance-and thereby reducing the need for high substrate reaction forces.
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Primatas , Sciuridae , Animais , Fenômenos Biomecânicos , LocomoçãoRESUMO
BACKGROUND: Skin abscesses are a common emergency presentation often requiring incision and drainage; however, issues with theatre access lead to delays in management and high costs. The long-term impact in a tertiary centre of a standardised day-only protocol is unknown. The aim was to evaluate the impact of day-only skin abscess protocol (DOSAP) for emergency surgery of skin abscesses in a tertiary institution in Australia and to provide a blueprint for other institutions. METHODS: A retrospective cohort study analysed several time periods: Period A (July 2014 to 2015, n = 201) pre-DOSAP implementation, Period B (July 2016 to 2017, n = 259) post-DOSAP, and Period C (July 2018 to 2022, n = 1,625) prospectively analysed four 12-month periods to assess long-term utilisation of DOSAP. Primary outcomes were length of stay and delay to theatre. Secondary outcome measures included theatre start time, representation rates and total costs. Statistical analysis using nonparametric methods was used to analyse the data. RESULTS: There was a significant decrease in ward length of stay (1.25 days vs. 0.65 days, P < 0.0001), delay to theatre (0.81 days vs. 0.44 days, P < 0.0001) and theatre start time before 10AM (44 cases vs. 96 cases, P < 0.0001) after implementation of DOSAP. There was a significant decrease in median cost of admission of $711.74 after accounting for inflation. Period C reported 1,006 abscess presentations successfully managed by DOSAP over the four-year period. CONCLUSION: Our study demonstrates the successful implementation of DOSAP in an Australian tertiary centre. The ongoing utilisation of the protocol demonstrates the ease of applicability.
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Abscesso , Benchmarking , Humanos , Abscesso/cirurgia , Austrália , Estudos Retrospectivos , Drenagem/métodosRESUMO
OBJECTIVES: Australian guidelines recommend people aged 50-70 years old consider taking low-dose aspirin to reduce their risk of colorectal cancer. The aim was to design sex-specific decision aids (DAs) with clinician and consumer input, including expected frequency trees (EFTs) to communicate the risks and benefits of taking aspirin. METHODS: Semi-structured interviews were conducted with clinicians. Focus groups were conducted with consumers. The interview schedules covered ease of comprehension, design, potential effects on decision-making, and approaches to implementation of the DAs. Thematic analysis was employed; independent coding by 2 researchers was inductive. Themes were developed through consensus between authors. RESULTS: Sixty-four clinicians were interviewed over 6 months in 2019. Twelve consumers aged 50-70 years participated in two focus groups in February and March 2020. The clinicians agreed that the EFTs would be helpful to facilitate a discussion with patients but suggested including an additional estimate of the effects of aspirin on all-cause mortality. The consumers felt favourable about the DAs and suggested changes to the design and wording to ease comprehension. CONCLUSION: DAs were designed to communicate the risks and benefits of low-dose aspirin for disease prevention. The DAs are currently being trialled in general practice to determine their impact on informed decision-making and aspirin uptake.
Aspirin can help to prevent bowel cancer up by to 25% and the chances of dying from it by up to 33%. Australian guidelines recommend that people aged 5070 years old to consider taking low-dose aspirin to reduce their risk of bowel cancer. To encourage GPs and their patients to discuss the guidelines, we designed a brochure called a decision aid with the help of clinicians and people in the community of Victoria, Australia. The decision aid covered the benefits and risks of taking aspirin. Clinicians participated in interviews and provided feedback on the statistics presented in a chart called an expected frequency tree. People in the community participated in group discussions and improved the design and comprehension of the decision aid. The clinicians and people who participated in this study do not fully represent the diversity of the Australian population, as they were mostly white and highly educated. We are now testing if the decision aid is effective for supporting a discussion between patients and general practitioners, helping their patients make an informed decision about taking aspirin, and whether it encourages them to take aspirin daily after being shown the decision aid in general practice.
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Asymptomatic carriers of Plasmodium parasites hamper malaria control and eradication. Achieving malaria eradication requires ultrasensitive diagnostics for low parasite density infections (<100 parasites per microliter blood) that work in resource-limited settings (RLS). Sensitive point-of-care diagnostics are also lacking for nonfalciparum malaria, which is characterized by lower density infections and may require additional therapy for radical cure. Molecular methods, such as PCR, have high sensitivity and specificity, but remain high-complexity technologies impractical for RLS. Here we describe a CRISPR-based diagnostic for ultrasensitive detection and differentiation of Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae, using the nucleic acid detection platform SHERLOCK (specific high-sensitivity enzymatic reporter unlocking). We present a streamlined, field-applicable, diagnostic comprised of a 10-min SHERLOCK parasite rapid extraction protocol, followed by SHERLOCK for 60 min for Plasmodium species-specific detection via fluorescent or lateral flow strip readout. We optimized one-pot, lyophilized, isothermal assays with a simplified sample preparation method independent of nucleic acid extraction, and showed that these assays are capable of detection below two parasites per microliter blood, a limit of detection suggested by the World Health Organization. Our P. falciparum and P. vivax assays exhibited 100% sensitivity and specificity on clinical samples (5 P. falciparum and 10 P. vivax samples). This work establishes a field-applicable diagnostic for ultrasensitive detection of asymptomatic carriers as well as a rapid point-of-care clinical diagnostic for nonfalciparum malaria species and low parasite density P. falciparum infections.
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Portador Sadio/diagnóstico , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Técnicas e Procedimentos Diagnósticos , Técnicas Genéticas , Malária/diagnóstico , Plasmodium/genética , Plasmodium/isolamento & purificação , Portador Sadio/parasitologia , Humanos , Malária/parasitologia , Plasmodium/classificação , Plasmodium/fisiologiaRESUMO
Mycobacteria share an unusually complex, multilayered cell envelope, which contributes to adaptation to changing environments. The plasma membrane is the deepest layer of the cell envelope and acts as the final permeability barrier against outside molecules. There is an obvious need to maintain the plasma membrane integrity, but the adaptive responses of the plasma membrane to stress exposure remain poorly understood. Using chemical treatment and heat stress to fluidize the membrane, we show here that phosphatidylinositol (PI)-anchored plasma membrane glycolipids known as PI mannosides (PIMs) are rapidly remodeled upon membrane fluidization in Mycobacterium smegmatis. Without membrane stress, PIMs are predominantly in a triacylated form: two acyl chains of the PI moiety plus one acyl chain modified at one of the mannose residues. Upon membrane fluidization, we determined the fourth fatty acid is added to the inositol moiety of PIMs, making them tetra-acylated variants. Additionally, we show that PIM inositol acylation is a rapid response independent of de novo protein synthesis, representing one of the fastest mass conversions of lipid molecules found in nature. Strikingly, we found that M. smegmatis is more resistant to the bactericidal effect of a cationic detergent after benzyl alcohol pre-exposure. We further demonstrate that fluidization-induced PIM inositol acylation is conserved in pathogens such as Mycobacterium tuberculosis and Mycobacterium abscessus. Our results demonstrate that mycobacteria possess a mechanism to sense plasma membrane fluidity change. We suggest that inositol acylation of PIMs is a novel membrane stress response that enables mycobacterial cells to resist membrane fluidization.
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Inositol , Mycobacterium tuberculosis , Acilação , Álcoois Benzílicos , Detergentes , Ácidos Graxos , Glicolipídeos , Inositol/metabolismo , Manose/química , Manose/metabolismo , Manosídeos/química , Mycobacterium tuberculosis/metabolismo , Fosfatidilinositóis/metabolismoRESUMO
Background: Patiromer and sodium polystyrene sulfonate (SPS) are cation-exchangers approved for the treatment of chronic hyperkalemia. Data regarding their efficacy acutely is lacking. Despite this, both drugs are frequently used in the emergent setting. Objective: The purpose of this study was to compare the potassium reduction of patiromer to SPS within 6 to 24 hours following a single dose. Methods: This retrospective quality improvement project included hyperkalemic patients receiving 1 dose of patiromer or SPS and had a second potassium level drawn in 6 to 24 hours. Doses of 8.4 g of patiromer and 15 g of SPS were considered "low dose" while 16.8 g of patiromer and 30 g of SPS were considered "high dose." The presence of a dose-response relationship was assessed through a linear regression analysis. Results: Mean (SD) potassium reduction was higher in SPS than patiromer [0.76 (0.63) mEq/L vs 0.32 (0.65) mEq/L, (P = .001)]. A dose response relationship was not demonstrated in low versus high dose groups [-0.21 (0.14), P = .13] and CKD, ESRD, and renal transplant patients when compared to patients with normal renal function [0.11 (0.17), P = .51, -0.07 (0.19), P = -0.07 (0.19), P = .73, and -0.10 (0.22), P = .65]. Conclusions: This study suggests a clinically significant reduction in potassium with SPS compared to patiromer. Although SPS was successful in demonstrating this outcome, due to well-documented adverse reactions in the literature and a time to onset of 6 hours, it cannot be recommended for use in acute hyperkalemia either.
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BACKGROUND: Successful breast cancer screening relies on timely follow-up of abnormal mammograms. Delayed or failure to follow-up abnormal mammograms undermines the potential benefits of screening and is associated with poorer outcomes. However, a comprehensive review of inadequate follow-up of abnormal mammograms in primary care has not previously been reported in the literature. This review could identify modifiable factors that influence follow-up, which if addressed, may lead to improved follow-up and patient outcomes. METHODS: A systematic literature review to determine the extent of inadequate follow-up of abnormal screening mammograms in primary care and identify factors impacting on follow-up was conducted. Relevant studies published between 1 January, 1990 and 29 October, 2020 were identified by searching MEDLINE®, Embase, CINAHL® and Cochrane Library, including reference and citation checking. Joanna Briggs Institute Critical Appraisal Checklists were used to assess the risk of bias of included studies according to study design. RESULTS: Eighteen publications reporting on 17 studies met inclusion criteria; 16 quantitative and two qualitative studies. All studies were conducted in the United States, except one study from the Netherlands. Failure to follow-up abnormal screening mammograms within 3 and at 6 months ranged from 7.2-33% and 27.3-71.6%, respectively. Women of ethnic minority and lower education attainment were more likely to have inadequate follow-up. Factors influencing follow-up included physician-patient miscommunication, information overload created by automated alerts, the absence of adequate retrieval systems to access patient's results and a lack of coordination of patient records. Logistical barriers to follow-up included inconvenient clinic hours and inconsistent primary care providers. Patient navigation and case management with increased patient education and counselling by physicians was demonstrated to improve follow-up. CONCLUSIONS: Follow-up of abnormal mammograms in primary care is suboptimal. However, interventions addressing amendable factors that negatively impact on follow-up have the potential to improve follow-up, especially for populations of women at risk of inadequate follow-up.
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Neoplasias da Mama/diagnóstico , Mamografia/métodos , Idoso , Neoplasias da Mama/mortalidade , Feminino , Seguimentos , Humanos , Programas de Rastreamento , Pessoa de Meia-Idade , Atenção Primária à SaúdeRESUMO
Traumatic brain injury (TBI) is associated with poor intrinsic healing responses and long-term cognitive decline. A major pathological outcome of TBI is acute glutamate-mediated excitotoxicity (GME) experienced by neurons. Short peptides based on the neuroprotective extracellular glycoprotein ependymin have shown the ability to slow down the effect of GME - however, such short peptides tend to diffuse away from target sites after in vivo delivery. We have designed a self-assembling peptide containing an ependymin mimic that can form nanofibrous matrices. The peptide was evaluated in situ to assess neuroprotective utility after an acute fluidpercussion injury. This biomimetic matrix can conform to the intracranial damaged site after delivery, due its shear-responsive rheological properties. We demonstrated the potential efficacy of the peptide for supporting neuronal survival in vitro and in vivo. Our study demonstrates the potential of these implantable acellular hydrogels for managing the acute (up to 7 days) pathophysiological sequelae after traumatic brain injury. Further work is needed to evaluate less invasive administrative routes and long-term functional and behavioral improvements after injury.
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BACKGROUND: Surgical site infections (SSIs) after left ventricular assist device (LVAD) implantation are associated with high mortality, while surgical prophylaxis is variable. METHODS: This retrospective study included adult patients who underwent LVAD implantation at a single center. We compared outcomes in patients who received narrow antimicrobial prophylaxis (cefazolin, vancomycin, or both) to those who received broad antimicrobial prophylaxis (any antimicrobial combination targeting gram-positive and gram-negative organisms not included in the narrow group) at 30-day and 1-year postimplantation. Cox-proportional hazards models and log-rank tests were used for survival analysis. RESULTS: Among the 39 and 65 patients comprising narrow and broad groups respectively, there was no difference in rate of SSI at 30 days (6.2% vs. 12.8%, p = .290) and 1 year (16.9% vs. 25.6%, p = .435). Comparing narrow to broad prophylaxis, the risk of mortality (hazard ratio [HR] = 0.44, 95% confidence interval [CI] = 0.15-1.35, logrank p = .14), and composite of mortality and infection was reduced (HR = 0.92, 95% CI = 0.45-1.88, logrank p = .83), but did not reach statistical significance. Most culture positive infections were due to gram-positive bacteria (70%) and the most common organisms were the Staphylococcus spp (47%). There were no significant differences in the rate of SSI at 1-year (p = 1.00) and mortality (p = .33) by device type. CONCLUSIONS: The rates of infection and all-cause mortality were not different between patients who received narrow or broad prophylaxis. This highlights an opportunity for institutions to narrow their surgical infection prophylaxis protocols to primarily cover gram-positive organisms.
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Anti-Infecciosos , Coração Auxiliar , Adulto , Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Antibioticoprofilaxia , Humanos , Estudos Retrospectivos , Infecção da Ferida Cirúrgica/tratamento farmacológico , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/prevenção & controleRESUMO
OBJECTIVE: Recent studies have suggested that diminished Ccr5 functioning has an effect on synaptic plasticity and hippocampal memory in mouse models. CCR5-delta32, a 32-bp frameshift deletion in human CCR5 encoding a nonfunctional receptor, has been reported to have a protective effect against human immunodeficiency virus infection but its role as a modifier of neurodegenerative disease has been minimally explored. We investigated whether the CCR5-delta32 polymorphism could have an effect in the context of human neurodegenerative diseases. METHODS: We examined the frequency of the CCR5-delta32 polymorphism in a large and well-characterized cohort including 1425 patients with neurodegenerative dementias and 2032 controls. RESULTS: We did not observe a significant association between the CCR5-delta32 polymorphism and any of the neurodegenerative diseases screened in this study. However, we observed an earlier age of onset among neurodegenerative disease patients carrying the CCR5-delta32 allele. CONCLUSIONS: Although our findings were inconclusive, the earlier age of onset observed among neurodegenerative disease patients carrying the CCR5-delta32 allele suggests that the deletion may have a detrimental effect in the context of neurodegeneration.
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Idade de Início , Doenças Neurodegenerativas/genética , Polimorfismo Genético , Receptores CCR5/genética , Adulto , Alelos , California , Estudos de Coortes , Humanos , Pessoa de Meia-IdadeRESUMO
Molecular chaperones, particularly the 70-kDa heat shock proteins (Hsp70s), are key orchestrators of the cellular stress response. To perform their critical functions, Hsp70s require the presence of specific co-chaperones, which include nucleotide exchange factors containing the BCL2-associated athanogene (BAG) domain. BAG-1 is one of these proteins that function in a wide range of cellular processes, including apoptosis, protein refolding, and degradation, as well as tumorigenesis. However, the origin of BAG-1 proteins and their evolution between and within species are mostly uncharacterized. This report investigated the macro- and micro-evolution of BAG-1 using orthologous sequences and single nucleotide polymorphisms (SNPs) to elucidate the evolution and understand how natural variation affects the cellular stress response. We first collected and analyzed several BAG-1 sequences across animals, plants, and fungi; mapped intron positions and phases; reconstructed phylogeny; and analyzed protein characteristics. These data indicated that BAG-1 originated before the animals, plants, and fungi split, yet most extant fungal species have lost BAG-1. Furthermore, although BAG-1's structure has remained relatively conserved, kingdom-specific conserved differences exist at sites of known function, suggesting functional specialization within each kingdom. We then analyzed SNPs from the 1000 genomes database to determine the evolutionary patterns within humans. These analyses revealed that the SNP density is unequally distributed within the BAG1 gene, and the ratio of non-synonymous/synonymous SNPs is significantly higher than 1 in the BAG domain region, which is an indication of positive selection. To further explore this notion, we performed several biochemical assays and found that only one out of five mutations tested altered the major co-chaperone properties of BAG-1. These data collectively suggest that although the co-chaperone functions of BAG-1 are highly conserved and can probably tolerate several radical mutations, BAG-1 might have acquired specialized and potentially unexplored functions during the evolutionary process.
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Proteínas de Ligação a DNA/genética , Evolução Molecular , Mutação , Polimorfismo de Nucleotídeo Único , Seleção Genética , Fatores de Transcrição/genética , Adenosina Trifosfatases/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Ligação a DNA/metabolismo , Humanos , Filogenia , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/metabolismoRESUMO
Beta-adrenergic receptor (ß-AR) activation by norepinephrine (NE) enhances memory and stabilizes long-term potentiation (LTP), a form of synaptic plasticity believed to underlie some forms of hippocampal memory. LTP can occur at multiple synaptic pathways as a result of strong stimulation to one pathway preceding milder stimulation of an adjacent, independent pathway. Synaptic tagging allows LTP to be transferred, or captured, at heterosynaptic pathways. Previous research has shown that ß-AR activation promotes heterosynaptic LTP by engaging various signaling cascades. In particular, cyclic adenosine monophosphate (cAMP) activates cAMP-dependent protein kinase A (PKA) and guanine nucleotide exchange protein activated by cAMP (Epac), to enhance LTP. Epac activation can occlude subsequent induction of stable homosynaptic LTP after ß-AR activation, but it is unclear whether Epac activation is required for heterosynaptic LTP following pairing of the natural transmitter, NE, with one 100 Hz train of stimulation ("NE-LTP"). Using electrophysiologic recordings of CA1 field excitatory postsynaptic potentials during stimulation of two independent synaptic pathways in murine hippocampal slices, we show that distinct inhibitors of Epac blocked stabilization of homo- and heterosynaptic NE-LTP. PKA inhibition also attenuated heterosynaptic transfer of NE-LTP, but only when a PKA inhibitor was applied during tetanization of a second, heterosynaptic pathway that was not treated with NE. Our data suggest that NE, paired with 100 Hz, activates Epac to stabilize homo- and heterosynaptic LTP. Epac may regulate the production of plasticity-related proteins and subsequent synaptic capture of NE-LTP at a heterosynaptic pathway. Epac activation under these conditions may enable behavioral experiences that engage noradrenergic inputs to hippocampal circuits to be transformed into stable long-term memories.
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Fatores de Troca do Nucleotídeo Guanina/metabolismo , Hipocampo/metabolismo , Potenciação de Longa Duração/fisiologia , Norepinefrina/metabolismo , Sinapses/metabolismo , Animais , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Estimulação Elétrica , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Hipocampo/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Receptores Adrenérgicos beta/metabolismo , Sinapses/efeitos dos fármacos , Técnicas de Cultura de TecidosRESUMO
Beta-adrenergic receptors (ß-ARs) prime hippocampal synapses to stabilize long-term potentiation (LTP). This "metaplasticity" can persist for 1-2 h after pharmacologic activation of ß-ARs. It requires activation of PKA (cAMP-dependent protein kinase) during ß-AR priming. A-kinase anchoring proteins (AKAPs) tether PKA to downstream signaling proteins. We hypothesized that induction of this metaplasticity requires intact functioning of AKAPs. Acute application of stearated ht31, a membrane-permeant inhibitor of AKAPs, either during ß-AR activation 30 min prior to LTP induction or during LTP induction, attenuated the persistence of LTP. A control, inactive ht31 peptide did not affect ß-AR-mediated metaplasticity. These findings implicate PKA anchoring in the induction of ß-adrenergic metaplasticity of LTP.
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Proteínas de Ancoragem à Quinase A/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Hipocampo/fisiologia , Potenciação de Longa Duração/fisiologia , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Receptores Adrenérgicos beta/fisiologia , Animais , Potenciais Pós-Sinápticos Excitadores , Masculino , Camundongos Endogâmicos C57BL , Sinapses/fisiologiaRESUMO
Endoplasmic reticulum (ER) stress is a form of cellular stress that is experienced by cells both under normal physiological conditions such as in professional secretory cells and disease states such as cancer, diabetes, and neurodegeneration. Upon facing ER stress, cells activate a conserved signaling pathway called the unfolded protein response (UPR) to restore normal function by halting general protein translation, upregulating expression of chaperones, and promoting ER-associated degradation. However, if the stress is overwhelming and cells are not able to recover within a reasonable time frame, the UPR ultimately commits cells to programmed cell death. How cells make this life-or-death decision remains an exciting yet poorly understood phenomenon. Here, we show that Gα-interacting vesicle-associated protein (GIV) aka Girdin plays an important role in promoting cell survival during ER stress. Cells lacking GIV are impaired in activating the pro-survival Akt pathway upon induction of ER stress. These cells also show enhanced levels of the pro-apoptotic transcription factor, CCAAT/enhancer binding protein homologous protein (CHOP) as compared to control cells. Due to decreased pro-survival signals and a concomitant increase in pro-apoptotic signals, GIV-depleted cells show a significant reduction in cell survival upon prolonged ER stress which can be rescued by re-expression of GIV or by directly activating Akt in these cells. Together, this study shows a novel, cytoprotective role for GIV in ER-stressed cells and furthers our understanding of the mechanisms that contribute to cell survival during ER stress.
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Estresse do Retículo Endoplasmático/fisiologia , Proteínas dos Microfilamentos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator de Transcrição CHOP/metabolismo , Resposta a Proteínas não Dobradas , Proteínas de Transporte Vesicular/metabolismo , Sobrevivência Celular , Células HeLa , HumanosRESUMO
In this report, we investigated the effects of natural single nucleotide polymorphisms on the function of HSPA1A, the major stress-inducible Hsp70 gene in humans. We first established that all mutant proteins retain their ability to hydrolyze ATP, but three of them had a significantly lower rate of ATP hydrolysis as compared to the wild-type (WT) protein. We also used Isothermal Titration Calorimetry and found that although all mutants bind to protein substrate with dissociation constants similar to the WT protein, four of them had increased reaction entropies. We also tested whether these mutations affect the ability of HSPA1A to refold heat-denatured luciferase. These assays revealed that one mutation resulted in significantly lower levels while a second one resulted in higher levels of the refolded enzyme. We then determined whether the mutations affected the ability of HSPA1A to prevent apoptosis caused by poly-glutamine carrying huntingtin proteins. This assay determined that three of the mutations caused increased cell apoptosis as compared to the WT. Our results reveal that although none of these naturally occurring mutations exists on positions of known function, some alter the molecular chaperone activities of HSPA1A most probably by affecting the allosteric communication between its two major domains.
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Proteínas de Choque Térmico HSP70/genética , Resposta ao Choque Térmico/genética , Mutação/genética , Trifosfato de Adenosina/metabolismo , Apoptose , Proteínas de Choque Térmico HSP70/química , Células HeLa , Humanos , Modelos Moleculares , Agregados Proteicos , Ligação Proteica , Redobramento de Proteína , Especificidade por SubstratoRESUMO
Altered synaptic strength underlies information storage in neural circuits. Neuromodulatory transmitters such as norepinephrine (NE) facilitate long-lasting synaptic plasticity by recruiting and modifying multiple molecular elements of synaptic signaling, including specific transmitter receptors, intracellular protein kinases, and translation initiation. NE regulates multiple brain functions such as attention, perception, arousal, sleep, learning, and memory. The mammalian hippocampus receives noradrenergic innervation and hippocampal neurons express ß-adrenergic receptors (ß-ARs), which bind NE and are critical for gating the induction of long-lasting forms of synaptic potentiation. These forms of long-term potentiation (LTP) are believed to importantly contribute to long-term storage of spatial and contextual memories in neural circuits. In this article, in honor of Prof. Harold Atwood, we review the contributions of ß-ARs towards gating the expression of protein synthesis-dependent, long-lasting hippocampal LTP. We focus on the roles of ß-ARs in modifying ion channels, glutamatergic AMPA receptors, and translation initiation factors during LTP. We discuss prospective research strategies that may lead to increased understanding of the roles of NE in regulating neural circuit physiology; these may uncover novel therapies for treatment of specific neurological disorders linked to aberrant circuit activity and dysfunctional noradrenergic synaptic transmission.
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Hipocampo/fisiologia , Potenciação de Longa Duração/fisiologia , Receptores Adrenérgicos beta/fisiologia , Animais , HumanosRESUMO
Implantation of acellular biomimetic scaffolds with proangiogenic motifs may have exciting clinical utility for the treatment of ischemic pathologies such as myocardial infarction. Although direct delivery of angiogenic proteins is a possible treatment option, smaller synthetic peptide-based nanostructured alternatives are being investigated due to favorable factors, such as sustained efficacy and high-density epitope presentation of functional moieties. These peptides may be implanted in vivo at the site of ischemia, bypassing the first-pass metabolism and enabling long-term retention and sustained efficacy. Mimics of angiogenic proteins show tremendous potential for clinical use. We discuss possible approaches to integrate the functionality of such angiogenic peptide mimics into self-assembled peptide scaffolds for application in functional tissue regeneration.