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Excessive fructose consumption is a primary contributor to the global surges in obesity, cancer, and metabolic syndrome. Fructolysis is not robustly regulated and is initiated by ketohexokinase (KHK). In this study, we determined the crystal structure of KHK-A, one of two human isozymes of KHK, in the apo-state at 1.85 Å resolution, and we investigated the roles of residues in the fructose-binding pocket by mutational analysis. Introducing alanine at D15, N42, or N45 inactivated KHK-A, whereas mutating R141 or K174 reduced activity and thermodynamic stability. Kinetic studies revealed that the R141A and K174A mutations reduced fructose affinity by 2- to 4-fold compared to WT KHK-A, without affecting ATP affinity. Molecular dynamics simulations provided mechanistic insights into the potential roles of the mutated residues in ligand coordination and the maintenance of an open state in one monomer and a closed state in the other. Protein-protein interactome analysis indicated distinct expression patterns and downregulation of partner proteins in different tumor tissues, warranting a reevaluation of KHK's role in cancer development and progression. The connections between different cancer genes and the KHK signaling pathway suggest that KHK is a potential target for preventing cancer metastasis. This study enhances our understanding of KHK-A's structure and function and offers valuable insights into potential targets for developing treatments for obesity, cancer, and metabolic syndrome.
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3-Chymotrypsin-like protease (3CLpro) is a promising drug target for coronavirus disease 2019 and related coronavirus diseases because of the essential role of this protease in processing viral polyproteins after infection. Understanding the detailed catalytic mechanism of 3CLpro is essential for designing effective inhibitors of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Molecular dynamics studies have suggested pH-dependent conformational changes of 3CLpro, but experimental pH profiles of SARS-CoV-2 3CLpro and analyses of the conserved active-site histidine residues have not been reported. In this work, pH-dependence studies of the kinetic parameters of SARS-CoV-2 3CLpro revealed a bell-shaped pH profile with 2 pKa values (6.9 ± 0.1 and 9.4 ± 0.1) attributable to ionization of the catalytic dyad His41 and Cys145, respectively. Our investigation of the roles of conserved active-site histidines showed that different amino acid substitutions of His163 produced inactive enzymes, indicating a key role of His163 in maintaining catalytically active SARS-CoV-2 3CLpro. By contrast, the H164A and H172A mutants retained 75% and 26% of the activity of WT, respectively. The alternative amino acid substitutions H172K and H172R did not recover the enzymatic activity, whereas H172Y restored activity to a level similar to that of the WT enzyme. The pH profiles of H164A, H172A, and H172Y were similar to those of the WT enzyme, with comparable pKa values for the catalytic dyad. Taken together, the experimental data support a general base mechanism of SARS-CoV-2 3CLpro and indicate that the neutral states of the catalytic dyad and active-site histidine residues are required for maximum enzyme activity.
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Biocatálisis , Proteasas 3C de Coronavirus , Histidina , SARS-CoV-2 , Humanos , Histidina/genética , Histidina/metabolismo , Concentración de Iones de Hidrógeno , SARS-CoV-2/enzimología , Proteasas 3C de Coronavirus/antagonistas & inhibidores , Proteasas 3C de Coronavirus/química , Proteasas 3C de Coronavirus/genética , Proteasas 3C de Coronavirus/metabolismo , Dominio Catalítico , Cinética , Sustitución de AminoácidosRESUMEN
BACKGROUND: Comorbidities such as obesity, hypertension, and diabetes are associated with COVID-19 development and severity, probably due to immune dysregulation; however, the mechanisms underlying these associations are not clear. The immune signatures of hypertensive patients with obesity with COVID-19 may provide new insight into the mechanisms of immune dysregulation and progression to severe disease in these patients. METHODS: Hypertensive patients were selected prospectively from a multicenter registry of adults hospitalized with COVID-19 and stratified according to obesity (BMI ≥ 30 kg/m²). Clinical data including baseline characteristics, complications, treatment, and 46 immune markers were compared between groups. Logistic regression was performed to identify variables associated with the risk of COVID-19 progression in each group. RESULTS: The sample comprised 213 patients (89 with and 124 without obesity). The clinical profiles of patients with and without obesity differed, suggesting potential interactions with COVID-19 severity. Relative to patients without obesity, patients with obesity were younger and fewer had cardiac disease and myocardial injury. Patients with obesity had higher EGF, GCSF, GMCSF, interleukin (IL)-1ra, IL-5, IL-7, IL-8, IL-15, IL-1ß, MCP 1, and VEGF levels, total lymphocyte counts, and CD8+ CD38+ mean fluorescence intensity (MFI), and lower NK-NKG2A MFI and percentage of CD8+ CD38+ T cells. Significant correlations between cytokine and immune cell expression were observed in both groups. Five variables best predicted progression to severe COVID-19 in patients with obesity: diabetes, the EGF, IL-10, and IL-13 levels, and the percentage of CD8+ HLA-DR+ CD38+ cells. Three variables were predictive for patients without obesity: myocardial injury and the percentages of B lymphocytes and HLA-DR+ CD38+ cells. CONCLUSION: Our findings suggest that clinical and immune variables and obesity interact synergistically to increase the COVID-19 progression risk. The immune signatures of hypertensive patients with and without obesity severe COVID-19 highlight differences in immune dysregulation mechanisms, with potential therapeutic applications.
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COVID-19 , Diabetes Mellitus , Hipertensión , Adulto , Humanos , Linfocitos T CD8-positivos , COVID-19/complicaciones , COVID-19/metabolismo , Factor de Crecimiento Epidérmico/metabolismo , Factor A de Crecimiento Endotelial Vascular , Antígenos HLA-DR/metabolismo , Hipertensión/complicaciones , Hipertensión/epidemiología , Hipertensión/metabolismo , Obesidad/complicaciones , Obesidad/metabolismoRESUMEN
BACKGROUND: Ventilation management may differ between COVID-19 ARDS (COVID-ARDS) patients and patients with pre-COVID ARDS (CLASSIC-ARDS); it is uncertain whether associations of ventilation management with outcomes for CLASSIC-ARDS also exist in COVID-ARDS. METHODS: Individual patient data analysis of COVID-ARDS and CLASSIC-ARDS patients in six observational studies of ventilation, four in the COVID-19 pandemic and two pre-pandemic. Descriptive statistics were used to compare epidemiology and ventilation characteristics. The primary endpoint were key ventilation parameters; other outcomes included mortality and ventilator-free days and alive (VFD-60) at day 60. RESULTS: This analysis included 6702 COVID-ARDS patients and 1415 CLASSIC-ARDS patients. COVID-ARDS patients received lower median VT (6.6 [6.0 to 7.4] vs 7.3 [6.4 to 8.5] ml/kg PBW; p < 0.001) and higher median PEEP (12.0 [10.0 to 14.0] vs 8.0 [6.0 to 10.0] cm H2O; p < 0.001), at lower median ΔP (13.0 [10.0 to 15.0] vs 16.0 [IQR 12.0 to 20.0] cm H2O; p < 0.001) and higher median Crs (33.5 [26.6 to 42.1] vs 28.1 [21.6 to 38.4] mL/cm H2O; p < 0.001). Following multivariable adjustment, higher ΔP had an independent association with higher 60-day mortality and less VFD-60 in both groups. Higher PEEP had an association with less VFD-60, but only in COVID-ARDS patients. CONCLUSIONS: Our findings show important differences in key ventilation parameters and associations thereof with outcomes between COVID-ARDS and CLASSIC-ARDS. TRIAL REGISTRATION: Clinicaltrials.gov (identifier NCT05650957), December 14, 2022.
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COVID-19 , Neumonía , Respiración Artificial , Síndrome de Dificultad Respiratoria , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , COVID-19/mortalidad , COVID-19/terapia , Síndrome de Dificultad Respiratoria/mortalidad , Síndrome de Dificultad Respiratoria/terapia , Resultado del Tratamiento , Neumonía/complicacionesRESUMEN
The main protease of SARS-CoV-2, 3-chymotrypsin-like protease (3CLpro), is a prominent target for antiviral development due to its essential role in the viral life cycle. Research has largely focused on competitive inhibitors of 3CLpro that target the active site. However, allosteric sites distal to the peptide substrate-binding region are also potential targets for the design of reversible noncompetitive inhibitors. Computational analyses have examined the importance of key contacts at allosteric sites of 3CLpro, but these contacts have not been validated experimentally. In this work, four druggable pockets spanning the surface of SARS-CoV-2 3CLpro were predicted: pocket 1 is the active site, whereas pockets 2, 3, and 4 are located away from the active site at the interface of domains II and III. Site-directed alanine mutagenesis of selected residues with important structural interactions revealed that 7 of 13 active site residues (N28, R40, Y54, S147, Y161, D187 and Q192) and 7 of 12 allosteric site residues (T111, R131, N133, D197, N203, D289 and D295) are essential for maintaining catalytically active and thermodynamically stable 3CLpro. Alanine substitution at these key amino acid residues inactivated or reduced the activity of 3CLpro. In addition, the thermodynamic stability of 3CLpro decreased in the presence of some of these mutations. This work provides experimental validation of essential contacts in the active and allosteric sites of 3CLpro that could be targeted with competitive and noncompetitive inhibitors as new therapeutics against COVID-19.
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3C-like protease (3CLpro) processes and liberates functional viral proteins essential for the maturation and infectivity of severe acute respiratory syndrome coronavirus 2, the virus responsible for COVID-19. It has been suggested that 3CLpro is catalytically active as a dimer, making the dimerization interface a target for antiviral development. Guided by structural analysis, here we introduced single amino acid substitutions at nine residues at three key sites of the dimer interface to assess their impact on dimerization and activity. We show that at site 1, alanine substitution of S1 or E166 increased by twofold or reduced relative activity, respectively. At site 2, alanine substitution of S10 or E14 eliminated activity, whereas K12A exhibited â¼60% relative activity. At site 3, alanine substitution of R4, E290, or Q299 eliminated activity, whereas S139A exhibited 46% relative activity. We further found that the oligomerization states of the dimer interface mutants varied; the inactive mutants R4A, R4Q, S10A/C, E14A/D/Q/S, E290A, and Q299A/E were present as dimers, demonstrating that dimerization is not an indication of catalytically active 3CLpro. In addition, present mostly as monomers, K12A displayed residual activity, which could be attributed to the conspicuous amount of dimer present. Finally, differential scanning calorimetry did not reveal a direct relationship between the thermodynamic stability of mutants with oligomerization or catalytic activity. These results provide insights on two allosteric sites, R4/E290 and S10/E14, that may promote the design of antiviral compounds that target the dimer interface rather than the active site of severe acute respiratory syndrome coronavirus 2 3CLpro.
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Proteasas 3C de Coronavirus , SARS-CoV-2 , Alanina/química , Sustitución de Aminoácidos , Antivirales/química , Proteasas 3C de Coronavirus/metabolismo , Multimerización de Proteína , SARS-CoV-2/enzimologíaRESUMEN
PURPOSE: Myocardial injury is common in hypertensive patients with 2019 coronavirus disease (COVID-19). Immune dysregulation could be associated to cardiac injury in these patients, but the underlying mechanism has not been fully elucidated. METHODS: All patients were selected prospectively from a multicenter registry of adults hospitalized with confirmed COVID-19. Cases had hypertension and myocardial injury, defined by troponin levels above the 99th percentile upper reference limit, and controls were hypertensive patients with no myocardial injury. Biomarkers and immune cell subsets were quantified and compared between the two groups. A multiple logistic regression model was used to analyze the associations of clinical and immune variables with myocardial injury. RESULTS: The sample comprised 193 patients divided into two groups: 47 cases and 146 controls. Relative to controls, cases had lower total lymphocyte count, percentage of T lymphocytes, CD8+CD38+ mean fluorescence intensity (MFI), and percentage of CD8+ human leukocyte antigen DR isotope (HLA-DR)+ CD38-cells and higher percentage of natural killer lymphocytes, natural killer group 2A (NKG2A)+ MFI, percentage of CD8+CD38+cells, CD8+HLA-DR+MFI, CD8+NKG2A+MFI, and percentage of CD8+HLA-DR-CD38+cells. On multivariate regression, the CD8+HLA-DR+MFI, CD8+CD38+MFI, and total lymphocyte count were associated significantly with myocardial injury. CONCLUSION: Our findings suggest that lymphopenia, CD8+CD38+MFI, and CD8+HLA-DR+MFI are immune biomarkers of myocardial injury in hypertensive patients with COVID-19. The immune signature described here may aid in understanding the mechanisms underlying myocardial injury in these patients. The study data might open a new window for improvement in the treatment of hypertensive patients with COVID-19 and myocardial injury.
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Linfocitos T CD8-positivos , COVID-19 , Adulto , Humanos , ADP-Ribosil Ciclasa 1 , COVID-19/complicaciones , Antígenos HLA-DR , Biomarcadores , Activación de LinfocitosRESUMEN
The exacerbation of the inflammatory response caused by SARS-CoV-2 in adults promotes the production of soluble mediators that could act as diagnostic and prognostic biomarkers for COVID-19. Among the potential biomarkers, the soluble triggering receptor expressed on myeloid cell-1 (sTREM-1) has been described as a predictor of inflammation severity. The aim was to evaluate sTREM-1 and cytokine serum concentrations in pediatric patients during the acute and convalescent phases of COVID-19. This was a prospective study that included 53 children/adolescents with acute COVID-19 (Acute-CoV group); 54 who recovered from COVID-19 (Post-CoV group) and 54 controls (Control group). Preexisting chronic conditions were present in the three groups, which were defined as follows: immunological diseases, neurological disorders, and renal and hepatic failures. The three groups were matched by age, sex, and similar preexisting chronic conditions. No differences in sTREM-1 levels were detected among the groups or when the groups were separately analyzed by preexisting chronic conditions. However, sTREM-1 analysis in the seven multisystemic inflammatory syndrome children (MIS-C) within the Acute-Cov group showed that sTREM-1 concentrations were higher in MIS-C vs non-MIS-C acute patients. Then, the receiver operating curve analysis (ROC) performed with MIS-C acute patients revealed a significant AUC of 0.870, and the sTREM-1 cutoff value of > 5781 pg/mL yielded a sensitivity of 71.4 % and a specificity of 91.3 % for disease severity, and patients with sTREM-1 levels above this cutoff presented an elevated risk for MIS-C development in 22.85-fold (OR = 22.85 [95 % CI 1.64-317.5], p = 0.02). The cytokine analyses in the acute phase revealed that IL-6, IL-8, and IL-10 concentrations were elevated regardless of whether the patient developed MIS-C, and those levels decreased in the convalescent phase, even when compared with controls. Spearman correlation analysis generated positive indexes between sTREM-1 and IL-12 and TNF-α concentrations, only within the Acute-CoV group. Our findings revealed that sTREM-1 in pediatric patients has good predictive accuracy as an early screening tool for surveillance of MIS-C cases, even in patients with chronic underlying conditions.
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COVID-19 , Receptores Inmunológicos , Adulto , Humanos , Niño , Adolescente , Receptor Activador Expresado en Células Mieloides 1 , Glicoproteínas de Membrana , Estudios Prospectivos , COVID-19/diagnóstico , SARS-CoV-2 , Biomarcadores , CitocinasRESUMEN
NEW FINDINGS: What is the central question of this study? How are dynamic cerebral autoregulation and brain vasoreactivity influenced by severe aortic stenosis and its surgical treatment? What are the main findings and their importance? Dynamic cerebral autoregulation is preserved in the long term in patients with severe aortic stenosis and does not change after surgical aortic valve replacement. However, carbon dioxide vasoreactivity is impaired in these patients. ABSTRACT: Surgical aortic valve replacement (SAVR) alters the natural course of severe aortic stenosis (AS). In this study, we aimed to determine the effects of the disease on dynamic cerebral autoregulation and vasoreactivity (VR) and to assess their changes after SAVR. We recruited 23 patients diagnosed with severe AS eligible for SAVR and 15 healthy matched controls. AS patients had lower mean VR to CO2 (P = 0.005) than controls, but dynamic cerebral autoregulation was preserved. Cerebral haemodynamics showed no significant change after SAVR. Patients with smaller baseline aortic valve areas presented with smaller low frequency phase changes after surgery (P = 0.016). Severe AS does not seem to impact dynamic cerebral autoregulation but does reduce VR to CO2 . SAVR does not alter cerebral autoregulation nor vasoreactivity.
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Estenosis de la Válvula Aórtica , Implantación de Prótesis de Válvulas Cardíacas , Humanos , Válvula Aórtica/cirugía , Estudios Prospectivos , Estenosis de la Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/diagnóstico , Dióxido de Carbono , Resultado del Tratamiento , Factores de RiesgoRESUMEN
BACKGROUND: Patient-ventilator asynchronies are usually detected by visual inspection of ventilator waveforms but with low sensitivity, even when performed by experts in the field. Recently, estimation of the inspiratory muscle pressure (Pmus) waveforms through artificial intelligence algorithm has been proposed (Magnamed®, São Paulo, Brazil). We hypothesized that the display of these waveforms could help healthcare providers identify patient-ventilator asynchronies. METHODS: A prospective single-center randomized study with parallel assignment was conducted to assess whether the display of the estimated Pmus waveform would improve the correct identification of asynchronies in simulated clinical scenarios. The primary outcome was the mean asynchrony detection rate (sensitivity). Physicians and respiratory therapists who work in intensive care units were randomized to control or intervention group. In both groups, participants analyzed pressure and flow waveforms of 49 different scenarios elaborated using the ASL-5000 lung simulator. In the intervention group the estimated Pmus waveform was displayed in addition to pressure and flow waveforms. RESULTS: A total of 98 participants were included, 49 per group. The sensitivity per participant in identifying asynchronies was significantly higher in the Pmus group (65.8 ± 16.2 vs. 52.94 ± 8.42, p < 0.001). This effect remained when stratifying asynchronies by type. CONCLUSIONS: We showed that the display of the Pmus waveform improved the ability of healthcare professionals to recognize patient-ventilator asynchronies by visual inspection of ventilator tracings. These findings require clinical validation. TRIAL REGISTRATION: ClinicalTrials.gov: NTC05144607. Retrospectively registered 3 December 2021.
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Inteligencia Artificial , Respiración Artificial , Humanos , Brasil , Atención a la Salud , Personal de Salud , Músculos , Estudios Prospectivos , Ventiladores MecánicosRESUMEN
BACKGROUND: This study aims to identify which risk factors are associated with the appearance of an incisional hernia in a stoma site after its closure. This in the sake of identifying which patients would benefit from a preventative intervention and thus start implementing a cost-effective protocol for prophylactic mesh placement in high-risk patients. METHODS: A systematic review of PubMed, Cochrane library, and ScienceDirect was performed according to PRISMA guidelines. Studies reporting incidence, risk factors, and follow-up time for appearance of incisional hernia after stoma site closure were included. A fixed-effects and random effects models were used to calculate odds ratios' estimates and standardized mean values with their respective grouped 95% confidence interval. This to evaluate the association between possible risk factors and the appearance of incisional hernia after stoma site closure. RESULTS: Seventeen studies totaling 2899 patients were included. Incidence proportion between included studies was of 16.76% (CI95% 12.82; 21.62). Out of the evaluated factors higher BMI (p = 0.0001), presence of parastomal hernia (p = 0.0023), colostomy (p = 0,001), and end stoma (p = 0.0405) were associated with the appearance of incisional hernia in stoma site after stoma closure, while malignant disease (p = 0.0084) and rectum anterior resection (p = 0.0011) were found to be protective factors. CONCLUSIONS: Prophylactic mesh placement should be considered as an effective preventative intervention in high-risk patients (obese patients, patients with parastomal hernia, colostomy, and end stoma patients) with the goal of reducing incisional hernia rates in stoma site after closure while remaining cost-effective.
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Hernia Incisional , Estomas Quirúrgicos , Humanos , Hernia Incisional/epidemiología , Hernia Incisional/etiología , Hernia Incisional/prevención & control , Mallas Quirúrgicas/efectos adversos , Estomas Quirúrgicos/efectos adversos , Colostomía/efectos adversos , Factores de RiesgoRESUMEN
BACKGROUND: Since the beginning of the COVID-19 pandemic, therapeutic options for treating COVID-19 have been investigated at different stages of clinical manifestations. Considering the particular impact of COVID-19 in the Americas, this document aims to present recommendations for the pharmacological treatment of COVID-19 specific to this population. METHODS: Fifteen experts, members of the Brazilian Society of Infectious Diseases (SBI) and the Pan-American Association of Infectious Diseases (API) make up the panel responsible for developing this guideline. Questions were formulated regarding prophylaxis and treatment of COVID-19 in outpatient and inpatient settings. The outcomes considered in decision-making were mortality, hospitalisation, need for mechanical ventilation, symptomatic COVID-19 episodes, and adverse events. In addition, a systematic review of randomised controlled trials was conducted. The quality of evidence assessment and guideline development process followed the GRADE system. RESULTS: Nine technologies were evaluated, and ten recommendations were made, including the use of tixagevimab + cilgavimab in the prophylaxis of COVID-19, tixagevimab + cilgavimab, molnupiravir, nirmatrelvir + ritonavir, and remdesivir in the treatment of outpatients, and remdesivir, baricitinib, and tocilizumab in the treatment of hospitalised patients with severe COVID-19. The use of hydroxychloroquine or chloroquine and ivermectin was discouraged. CONCLUSION: This guideline provides recommendations for treating patients in the Americas following the principles of evidence-based medicine. The recommendations present a set of drugs that have proven effective in the prophylaxis and treatment of COVID-19, emphasising the strong recommendation for the use of nirmatrelvir/ritonavir in outpatients as the lack of benefit from the use of hydroxychloroquine and ivermectin.
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COVID-19 , Enfermedades Transmisibles , Humanos , Estados Unidos , SARS-CoV-2 , Ritonavir/uso terapéutico , Hidroxicloroquina/uso terapéutico , Pandemias/prevención & control , Brasil , Ivermectina , Enfermedades Transmisibles/tratamiento farmacológico , Antivirales/uso terapéuticoRESUMEN
Coronaviruses have been responsible for multiple challenging global pandemics, including coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Papain-like protease (PLpro), one of two cysteine proteases responsible for the maturation and infectivity of SARS-CoV-2, processes and liberates functional proteins from the viral polyproteins and cleaves ubiquitin and ISG15 modifications to inhibit innate immune sensing. Consequently, PLpro is an attractive target for developing COVID-19 therapies. PLpro contains a zinc-finger domain important for substrate binding and structural stability. However, the impact of metal ions on the activity and biophysical properties of SARS-CoV-2 PLpro has not been comprehensively studied. Here, we assessed the impacts of metal ions on the catalytic activity of PLpro. Zinc had the largest inhibitory effect on PLpro, followed by manganese. Calcium, magnesium, and iron had smaller or no effects on PLpro activity. EDTA at a concentration of 0.5â mM was essential for PLpro activity, likely by chelating trace metals that inhibit PLpro. IC50 values for ZnCl2, ZnSO4, and MnCl2 of 0.42 ± 0.02â mM, 0.35 ± 0.01â mM, and 2.6 ± 0.3â mM were obtained in the presence of 0.5â mM EDTA; in the absence of EDTA, the estimated IC50 of ZnCl2 was 14â µM. Tryptophan intrinsic fluorescence analysis confirmed the binding of zinc and manganese to PLpro, and differential scanning calorimetry revealed that zinc but not manganese reduced ΔHcal of PLpro. The results of this study provide a reference for further work targeting PLpro to prevent and treat COVID-19.
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Tratamiento Farmacológico de COVID-19 , SARS-CoV-2 , Humanos , Papaína/química , Papaína/metabolismo , Péptido Hidrolasas/metabolismo , Magnesio , Calcio , Triptófano , Ácido Edético , Ubiquitina/metabolismo , Poliproteínas , Iones , Zinc , HierroRESUMEN
Microorganisms in Antarctica are recognized for having crucial roles in ecosystems functioning and biogeochemical cycles. To explore the diversity and composition of microbial communities through different terrestrial and marine Antarctic habitats, we analyze 16S rRNA sequence datasets from fumarole and marine sediments, soil, snow and seawater environments. We obtained measures of alpha- and beta-diversities, as well as we have identified the core microbiome and the indicator microbial taxa of a particular habitat. Our results showed a unique microbial community structure according to each habitat, including specific taxa composing each microbiome. Marine sediments harbored the highest microbial diversity among the analyzed habitats. In the fumarole sediments, the core microbiome was composed mainly of thermophiles and hyperthermophilic Archaea, while in the majority of soil samples Archaea was absent. In the seawater samples, the core microbiome was mainly composed by cultured and uncultured orders usually identified on Antarctic pelagic ecosystems. Snow samples exhibited common taxa previously described for habitats of the Antarctic Peninsula, which suggests long-distance dispersal processes occurring from the Peninsula to the Continent. This study contributes as a baseline for further efforts on evaluating the microbial responses to environmental conditions and future changes.
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Bacterias , Microbiota , Bacterias/genética , Regiones Antárticas , ARN Ribosómico 16S/genética , Archaea/genética , Microbiota/genética , SueloRESUMEN
With the potential for coronaviruses to re-emerge and trigger future pandemics, the urgent development of antiviral inhibitors against SARS-CoV-2 is essential. The Mpro enzyme is crucial for disease progression and the virus's life cycle. It possesses allosteric sites that can hinder its catalytic activity, with some of these sites located at or near the dimerization interface. Among them, sites #2 and #5 possess druggable pockets and are predicted to bind drug-like molecules. Consequently, a commercially available ligand library containing ~7 million ligands was used to target site #2 via structure-based virtual screening. After extensive filtering, docking, and post-docking analyses, 53 compounds were chosen for biological testing. An oxindole derivative was identified as a Mpro non-competitive reversible inhibitor with a Ki of 115â µM and an IC50 of 101.9â µM. Throughout the 200â ns-long MD trajectories, our top hit has shown a very stable binding mode, forming several interactions with residues in sites #2 and #5. Moreover, derivatives of our top hit were acquired for biological testing to gain deeper insights into their structure-activity relationship. To sum up, drug-like allosteric inhibitors seem promising and can provide us with an additional weapon in our war against the recent pandemic, and possibly other coronaviruses-caused diseases.
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COVID-19 , SARS-CoV-2 , Humanos , Antivirales/química , Oxindoles/farmacología , Inhibidores de Proteasas/farmacología , Inhibidores de Proteasas/química , Simulación del Acoplamiento Molecular , Simulación de Dinámica MolecularRESUMEN
Spinal muscular atrophy (SMA) is considered one of the most common autosomal recessive disorders, with an estimated incidence of 1 in 10,000 live births. Testing for SMA has been recommended for inclusion in neonatal screening (NBS) panels since there are several therapies available and there is evidence of greater efficacy when introduced in the pre/early symptomatic phases. In Brazil, the National Neonatal Screening Program tests for six diseases, with a new law issued in 2021 stating that it should incorporate more diseases, including SMA. In the present study, dried blood spot (DBS) samples collected by the Reference Services of Neonatal Screening of RS and SP, to perform the conventional test were also screened for SMA, using real-time PCR, with SALSA MC002 technique. A total of 40,000 samples were analyzed, enabling the identification of four positive cases of SMA, that were confirmed by MLPA. Considering our sampling, Brazil seems to have an incidence comparable to the described in other regions. This work demonstrated that the use of the MC002 technique in samples routinely collected for the conventional NBS program is suitable to screen for SMA in our conditions and can be included in the expansion of the neonatal screening programs.
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Hexokinase (HK) catalyzes the first step in glucose metabolism, making it an exciting target for the inhibition of tumor initiation and progression due to their elevated glucose metabolism. The upregulation of hexokinase-2 (HK2) in many cancers and its limited expression in normal tissues make it a particularly attractive target for the selective inhibition of cancer growth and the eradication of tumors with limited side effects. The design of such safe and effective anticancer therapeutics requires the development of HK2-specific inhibitors that will not interfere with other HK isozymes. As HK2 is unique among HKs in having a catalytically active N-terminal domain (NTD), we have focused our attention on this region. We previously found that NTD activity is affected by the size of the linker helix-α13 that connects the N- and C-terminal domains of HK2. Three nonactive site residues (D447, S449, and K451) at the beginning of the linker helix-α13 have been found to regulate the NTD activity of HK2. Mutation of these residues led to increased dynamics, as shown via hydrogen deuterium exchange analysis and molecular dynamic simulations. D447A contributed the most to the enhanced dynamics of the NTD, with reduced calorimetric enthalpy of HK2. Similar residues exist in the C-terminal domain (CTD) but are unnecessary for HK1 and HK2 activity. Thus, we postulate these residues serve as a regulatory site for HK2 and may provide new directions for the design of anticancer therapeutics that reduce the rate of glycolysis in cancer through specific inhibition of HK2.
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Antineoplásicos/farmacología , Inhibidores Enzimáticos/farmacología , Hexoquinasa/metabolismo , Catálisis , Línea Celular Tumoral , Estabilidad de Enzimas , Glucólisis , Hexoquinasa/antagonistas & inhibidores , Hexoquinasa/química , Humanos , Cinética , Dominios Proteicos , Especificidad por SustratoRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for coronavirus disease 2019 (COVID-19), one of the most challenging global pandemics of the modern era. Potential treatment strategies against COVID-19 are yet to be devised. It is crucial that antivirals that interfere with the SARS-CoV-2 life cycle be identified and developed. 3-Chymotrypsin-like protease (3CLpro) is an attractive antiviral drug target against SARS-CoV-2, and coronaviruses in general, because of its role in the processing of viral polyproteins. Inhibitors of 3CLpro activity are screened in enzyme assays before further development of the most promising leads. Dimethyl sulfoxide (DMSO) is a common additive used in such assays and enhances the solubility of assay components. However, it may also potentially affect the stability and efficiency of 3CLpro but, to date, this effect had not been analyzed in detail. Here, we investigated the effect of DMSO on 3CLpro-catalyzed reaction. While DMSO (5%-20%) decreased the optimum temperature of catalysis and thermodynamic stability of 3CLpro, it only marginally affected the kinetic stability of the enzyme. Increasing the DMSO concentration up to 20% improved the catalytic efficiency and peptide-binding affinity of 3CLpro. At such high DMSO concentration, the solubility and stability of peptide substrate were improved because of reduced aggregation. In conclusion, we recommend 20% DMSO as the minimum concentration to be used in screens of 3CLpro inhibitors as lead compounds for the development of antiviral drugs against COVID-19.
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COVID-19/virología , Proteasas 3C de Coronavirus/metabolismo , Dimetilsulfóxido/farmacología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Regulación Viral de la Expresión Génica/efectos de los fármacos , SARS-CoV-2/enzimología , Simulación por Computador , Proteasas 3C de Coronavirus/genética , Humanos , Técnicas Analíticas Microfluídicas , Péptidos/metabolismo , Estabilidad ProteicaRESUMEN
OBJECTIVES: To describe the care provided by Brazilian nurses to patients with Juvenile Systemic Lupus Erythematosus (JSLE) using a self-administered questionnaire and to evaluate the possible association of demographic data and knowledge of the disease with availability of tools for diagnosis and treatment in Brazilian pediatric services. METHOD: This is a cross-sectional observational descriptive study that analyzed the care provided by Brazilian nurses to patients with JSLE based on the answers to a self-administered questionnaire. Questions included demographics of professionals, nursing consultation, usage of tools to assess disease activity, diagnostic criteria, general care, available practices, transition program, and practices needed for better care. RESULTS: A total of 111/373 (29.4%) questionnaires were completed, most professionals were female (90.1%). Hospitalization (45.9%) and poor medication adherence (27.9%) were the most reported problems, and lack of knowledge about the institutional transition process to adult care was mentioned by half of the professionals (50.5%). Comparisons of professionals on expected care of patients regarding the type of service, hospitalized patient care, and care provided to patients with JSLE did not reveal statistically significant differences (p > 0.05). Nurses who care for patients with JSLE are more likely to work in a public setting (14.5% vs. 36.8%, p = 0.048) and less likely to verify vaccination records (0.12.9% vs. 36.8%, p = 0.038). Nurses who worked in the inpatient setting with patients with JSLE were less likely to address pain concerns (11.7% vs. 61.6%, p < 0.0001) compared to nurses who didn't work with JSLE patients. However, they were more likely to discuss sunscreen use (54.9% vs. 25%, p < 0.05) and be part of a multi-disciplinary team (84.3 vs. 50%, p < 0.0001). CONCLUSIONS: This study demonstrates that the care provided by nurses to patients with JSLE does not consider all the resources available to assess the disease and occurs differently in the inpatient versus outpatient settings. Future research should address this gap in care. Lack of JSLE awareness was commonly reported among professionals, confirming the need for greater knowledge about JSLE, its treatment, and ways to improve adherence.
Asunto(s)
Lupus Eritematoso Sistémico , Adulto , Brasil/epidemiología , Niño , Estudios Transversales , Femenino , Humanos , Lupus Eritematoso Sistémico/diagnóstico , Lupus Eritematoso Sistémico/terapia , Encuestas y CuestionariosRESUMEN
Background: Well-designed clinical research needs to obtain information that is applicable to the general population. However, most current studies fail to include substantial cohorts of racial/ethnic minority populations. Such underrepresentation may lead to delayed diagnosis or misdiagnosis of disease, wide application of approved interventions without appropriate knowledge of their usefulness in certain populations, and development of recommendations that are not broadly applicable.Goals: To develop best practices for recruitment and retention of racial/ethnic minorities for clinical research in pulmonary, critical care, and sleep medicine.Methods: The American Thoracic Society convened a workshop in May of 2019. This included an international interprofessional group from academia, industry, the NIH, and the U.S. Food and Drug Administration, with expertise ranging from clinical and biomedical research to community-based participatory research methods and patient advocacy. Workshop participants addressed historical and current mistrust of scientific research, systemic bias, and social and structural barriers to minority participation in clinical research. A literature search of PubMed and Google Scholar was performed to support conclusions. The search was not a systematic review of the literature.Results: Barriers at the individual, interpersonal, institutional, and federal/policy levels were identified as limiting to minority participation in clinical research. Through the use of a multilevel framework, workshop participants proposed evidence-based solutions to the identified barriers.Conclusions: To date, minority participation in clinical research is not representative of the U.S. and global populations. This American Thoracic Society research statement identifies potential evidence-based solutions by applying a multilevel framework that is anchored in community engagement methods and patient advocacy.