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Background: Parenting a preterm infant can be incredibly challenging and stressful, particularly in the first year after discharge. Desirable parental role adaptation leads to appropriate parenting behaviors and parent-infant interaction, which are essential to child health and development. Aim: To investigate the level of parental role adaptation and its influencing factors among parents of preterm infants in the first year after hospital discharge according to Belsky's parenting process model among parents of preterm infants in the first year after hospital discharge. Methods: A cross-sectional study design was adopted using convenience sampling. Data were collected using the Parental Role Adaptation Scale (PRAS) in parents with preterm infants, the Perceived Social Support Scale (PSSS), the Coping Adaptation Processing Scale (CAPS-15), and a sociodemographic questionnaire. Descriptive statistics, non-parametric tests, Spearman correlation analyses, and multivariate linear regression were used to analyze the data. Results: In total, 300 Chinese parents were included in the analysis. In the multivariate analysis, first-time parent (p = 0.003), master's degree and above (p = 0.042), coping adaptation processing (p = 0.000), residence location (towns: p = 0.019, city: p = 0.028), monthly family income (6000-10,000: p = 0.000, >10,000: p = 0.000), and perceived social support (p = 0.001) were all significant predictors of parental role adaptation and collectively accounted for 56.8% of the variation in parental role adaptation of parents with preterm infants (F = 16.473, p < 0.001). Coping adaptation processing mediated the relationship between perceived social support and parental role adaptation (95% bootstrap CI = 0.022, 0.130). Conclusion: Chinese parents of preterm infants experience a moderate level of parental role adaptation when their child is discharged from the hospital to home. Parents who are not first-time parents, have master's degrees or above, live in towns or cities, have higher coping and adaptation abilities, have high monthly family income, and greater perceived social support have a higher level of parental role adaptation. Healthcare providers should pay more attention to parents with low socioeconomic status and encourage them to improve their coping and adaptation abilities and to utilize their formal and informal social support networks.
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BACKGROUND: Breast cancer (BRCA) represents a significant health challenge for women globally, with refractory cases showing resistance to current therapeutic strategies. The discovery of novel molecular markers and therapeutic targets is critical for improving outcomes in these patients. The primary aim of this study is to elucidate the role of tumor protein D52 (TPD52) as a novel molecular marker and potential therapeutic target to improve outcomes for BRCA patients. METHODS: Using bioinformatics methods, we screened and evaluated the expression, prognosis, and associated mechanisms of TPD52 in BRCA. Two hundred and thirty-eight BRCA cases and 19 control cases were collected from Shanghai First Maternity and Infant Hospital, and the protein expression of TPD52 was detected by immunohistochemistry, and the correlation between TPD52 and the prognosis of BRCA was analyzed. RESULTS: The expression of TPD52 in BRCA tissues was significantly higher than that in the control (P<0.001), displaying a strong association with key clinical variables, concurrently indicating an unfavorable prognostic implication. The survival analysis revealed high TPD52 expression was an independent adverse prognostic factor for overall (P=0.008) and disease-specific survival (P=0.005). Gene set enrichment analysis showed that TPD52 negatively correlated with estradiol, AMP-activated protein kinase, and other responses. Immune infiltration analysis showed that TPD52 was associated with immune cell infiltration, Th-1/Th-2 cell balance, and immune defense cells such as dendritic and plasmacytoid dendritic cells. It is further found that high TPD52 expression is associated with progression-free and disease-free survival from the analysis of immunohistochemical data of the patients at our hospital. CONCLUSIONS: In summary, TPD52 may serve as an independent prognostic biomarker for BRCA, which may represent a promising novel therapeutic target, particularly for the refractory estrogen receptor-positive (ER+)/progesterone receptor-positive (PR+)/human epidermal growth factor receptor 2-positive (HER2+) BRCA cases that have failed endocrine therapy and targeted treatment.
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Biomarcadores Tumorais , Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/patologia , Prognóstico , Biomarcadores Tumorais/metabolismo , Pessoa de Meia-Idade , Proteínas de Neoplasias/metabolismo , Receptores de Estrogênio/metabolismo , Receptor ErbB-2/metabolismo , Adulto , Receptores de Progesterona/metabolismoRESUMO
Halide methyltransferases (HMTs) provide an effective way to regenerate S-adenosyl methionine (SAM) from S-adenosyl homocysteine and reactive electrophiles, such as methyl iodide (MeI) and methyl toluene sulfonate (MeOTs). As compared with MeI, the cost-effective unnatural substrate MeOTs can be accessed directly from cheap and abundant alcohols, but shows only limited reactivity in SAM production. In this study, we developed a dynamic cross-correlation network analysis (DCCNA) strategy for quickly identifying hot spots influencing the catalytic efficiency of the enzyme, and applied it to the evolution of HMT from Paraburkholderia xenovorans. Finally, the optimal mutant, M4 (V55T/C125S/L127T/L129P), exhibited remarkable improvement, with a specific activity of 4.08â U/mg towards MeOTs, representing an 82-fold increase as compared to the wild-type (WT) enzyme. Notably, M4 also demonstrated a positive impact on the catalytic ability with other methyl donors. The structural mechanism behind the enhanced enzyme activity was uncovered by molecular dynamics simulations. Our work not only contributes a promising biocatalyst for the regeneration of SAM, but also offers a strategy for efficient enzyme engineering.
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Metiltransferases , Metiltransferases/metabolismo , Metiltransferases/química , Engenharia de Proteínas , Simulação de Dinâmica MolecularRESUMO
AIMS: To identify the contaminated areas of the hand collection and analyse the distribution characteristics of bacteria in the hand after swab collection. DESIGN: This study used a cross-sectional design. METHODS: A cross-sectional study sampling 50 pairs of hands (sampling hand and auxiliary hand) of healthcare workers was performed. Ten samples were collected from each participant. The optimal hand hygiene rates and bacterial colony counts of the whole hand and different hand sections without hand hygiene were identified as the primary outcomes. RESULTS: The optimal hand hygiene rates of the sampling hand and auxiliary hand were 88.8% (222/250) and 91.6% (229/250), respectively. The lowest optimal hand hygiene rates for the sampling hand and the auxiliary hand were both on the dorsal side of the finger and the dorsum of the hand (86.0%, 86.0% vs. 90.0%, 86.0%); the optimal hand hygiene rates for both sites of the sampling hand were 86.0% (43/50), and the optimal hand hygiene rates for the auxiliary hand were 90.0% (45/50) and 86.0% (43/50). The bacteria colony counts did not differ between the sampling hands and auxiliary hand. CONCLUSIONS: The dorsal side of the finger and dorsum of the hand were the most likely to be contaminated during oropharyngeal swab collection. Therefore, it is essential to pay extra attention to hand hygiene care of these two sites during the collection process to minimize the risk of cross-contamination. REPORTING METHOD: The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines were adopted in this study.
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We introduce a computational approach for the design of target-specific peptides. Our method integrates a Gated Recurrent Unit-based Variational Autoencoder with Rosetta FlexPepDock for peptide sequence generation and binding affinity assessment. Subsequently, molecular dynamics simulations are employed to narrow down the selection of peptides for experimental assays. We apply this computational strategy to design peptide inhibitors that specifically target ß-catenin and NF-κB essential modulator. Among the twelve ß-catenin inhibitors, six exhibit improved binding affinity compared to the parent peptide. Notably, the best C-terminal peptide binds ß-catenin with an IC50 of 0.010 ± 0.06 µM, which is 15-fold better than the parent peptide. For NF-κB essential modulator, two of the four tested peptides display substantially enhanced binding compared to the parent peptide. Collectively, this study underscores the successful integration of deep learning and structure-based modeling and simulation for target specific peptide design.
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Aprendizado Profundo , Simulação de Dinâmica Molecular , beta Catenina/metabolismo , NF-kappa B/metabolismo , Ligação Proteica , Peptídeos/químicaAssuntos
Carcinoma de Células Renais , Neoplasias Renais , Humanos , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/cirurgia , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/diagnóstico , Neoplasias Renais/patologia , Neoplasias Renais/cirurgia , Neoplasias Renais/diagnóstico , Prognóstico , Masculino , Carcinoma Papilar/patologia , Carcinoma Papilar/cirurgia , Carcinoma Papilar/diagnóstico , Feminino , Biomarcadores Tumorais/sangue , Pessoa de Meia-Idade , IdosoRESUMO
SUMMARY: Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is highly expressed in various types of cancers including breast cancer. However, the role of AhR with its endogenous ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) on the progression of breast cancer remains poorly understood. We aimed to investigate cell proliferation and migration states in breast cancer after activating AhR with the endogenous ligand ITE. Breast cancer tissue was evaluated by cell lines, immunohistochemistry, reverse transcription-polymerase chain reaction, cell proliferation, flow cytometry, migration assays and western blot techniques. We found that AhR was widely expressed in breast cancer tissues and metastasis lymph node tissues, but not in normal tissues. The expression AhR was independent between the age, grades and TNM classifications for breast cancer tissues. ITE treatment significantly induced the activation of AhR in a time-dependent manner in both MCF-7 and T47D breast cancer cell lines. Meanwhile, ITE did not affect the cell migration but significantly suppressed the cell proliferation in estrogen receptor positive (ER+) MCF-7 andT47D cells, which probably attribute to the induction of cell cycle arrest in G1 phase and shortened S phase. Further mechanism study showed that ERK1/2 and AKT signaling were required for the activation of AhR in MCF-7 cells. These data suggest that AhR is a potential new target for treating patients with breast cancer. ITE may be more potentially used for therapeutic intervention for breast cancer with the kind of ER(+).
El receptor de hidrocarburo de arilo (AhR) es un factor de transcripción activado por ligando que se expresa en gran medida en varios tipos de cáncer, incluido el cáncer de mama. Sin embargo, el papel de AhR con su ligando endógeno 2- (1'H-indol-3'-carbonil)-tiazol-4-ácido carboxílico metil éster (ITE) en la progresión del cáncer de mama sigue siendo poco conocido. Nuestro objetivo fue investigar la proliferación celular y los estados de migración en el cáncer de mama después de activar AhR con el ligando endógeno ITE. El tejido de cáncer de mama se evaluó mediante líneas celulares, inmunohistoquímica, reacción en cadena de la polimerasa con transcriptasa inversa, proliferación celular, citometría de flujo, ensayos de migración y técnicas de transferencia Western. Descubrimos que AhR se expresó ampliamente en tejidos de cáncer de mama y en linfonodos con metástasis, pero no en tejidos normales. La expresión AhR fue independiente entre la edad, grados y clasificaciones TNM para tejidos de cáncer de mama. El tratamiento con ITE indujo significativamente la activación de AhR de manera dependiente del tiempo en las líneas celulares de cancer de mama MCF-7 y T47D. Mientras tanto, ITE no afectó la migración celular, pero suprimió significativamente la proliferación celular en células MCF-7 y T47D con receptor de estrógeno positivo (ER+), lo que probablemente se atribuye a la inducción de la detención del ciclo celular en la fase G1 y la fase S acortada. Un estudio adicional del mecanismo mostró que las señales de ERK1/2 y AKT eran necesarias para la activación de AhR en las células MCF-7. Estos datos sugieren que AhR es un nuevo objetivo potencial para el tratamiento de pacientes con cáncer de mama. ITE puede ser utilizado más potencialmente en la intervención terapéutica para el cáncer de mama con el tipo de ER (+).
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Humanos , Feminino , Tiazóis/administração & dosagem , Neoplasias da Mama/patologia , Receptores de Hidrocarboneto Arílico/efeitos dos fármacos , Indóis/administração & dosagem , Tiazóis/farmacologia , Imuno-Histoquímica , Receptores de Estrogênio , Western Blotting , Citocromo P-450 CYP1A1/genética , Linhagem Celular Tumoral/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ensaios de Migração Celular , Citocromo P-450 CYP1B1/genética , Citometria de Fluxo , Indóis/farmacologiaRESUMO
The uptake of Ca2+ into and extrusion of calcium from the mitochondrial matrix, regulated by the mitochondrial Ca2+ uniporter (MCU), is a fundamental biological process that has crucial impacts on cellular metabolism, signaling, growth and survival. Herein, we report that the embryonic lethality of Mcu-deficient mice is fully rescued by orally supplementing ferroptosis inhibitor lipophilic antioxidant vitamin E and ubiquinol. Mechanistically, we found MCU promotes acetyl-CoA-mediated GPX4 acetylation at K90 residue, and K90R mutation impaired the GPX4 enzymatic activity, a step that is crucial for ferroptosis. Structural analysis supports the possibility that GPX4 K90R mutation alters the conformational state of the molecule, resulting in disruption of a salt bridge formation with D23, which was confirmed by mutagenesis studies. Finally, we report that deletion of MCU in cancer cells caused a marked reduction in tumor growth in multiple cancer models. In summary, our study provides a first direct link between mitochondrial calcium level and sustained GPX4 enzymatic activity to regulate ferroptosis, which consequently protects cancer cells from ferroptosis.
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A cardiac glycoside epoxide, (-)-cryptanoside A (1), was isolated from the stems of Cryptolepis dubia collected in Laos, for which the complete structure was confirmed by analysis of its spectroscopic and single-crystal X-ray diffraction data, using copper radiation at a low temperature. This cardiac glycoside epoxide exhibited potent cytotoxicity against several human cancer cell lines tested, including HT-29 colon, MDA-MB-231 breast, OVCAR3 and OVCAR5 ovarian cancer, and MDA-MB-435 melanoma cells, with the IC50 values found to be in the range 0.1-0.5 µM, which is comparable with that observed for digoxin. However, it exhibited less potent activity (IC50 1.1 µM) against FT194 benign/nonmalignant human fallopian tube secretory epithelial cells when compared with digoxin (IC50 0.16 µM), indicating its more selective activity toward human cancer versus benign/nonmalignant cells. (-)-Cryptanoside A (1) also inhibited Na+/K+-ATPase activity and increased the expression of Akt and the p65 subunit of NF-κB but did not show any effects on the expression of PI3K. A molecular docking profile showed that (-)-cryptanoside A (1) binds to Na+/K+-ATPase, and thus 1 may directly target Na+/K+-ATPase to mediate its cancer cell cytotoxicity.
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Antineoplásicos , Glicosídeos Cardíacos , Neoplasias Ovarianas , Humanos , Feminino , Glicosídeos Cardíacos/farmacologia , Glicosídeos Cardíacos/química , Cryptolepis/metabolismo , Apoptose , Simulação de Acoplamento Molecular , Linhagem Celular Tumoral , ATPase Trocadora de Sódio-Potássio , Antineoplásicos/farmacologia , Digoxina/farmacologiaRESUMO
My 5 moments (M5M) was used less frequently among cleaning staff members, suggesting that a poor compliance score in this group may not indicate deficient handwashing. This quasi-experimental study compared hand hygiene compliance (HHC), hand hygiene (HH) moments, and HH time distribution in the control group (no HH intervention; n = 21), case group 1 (normal M5M intervention; n = 26), case group 2 (extensive novel six moments (NSM) training; n = 24), and case group 3 (refined NSM training; n = 18). The intervention's effect was evaluated after 3 months. The HHC gap among the four groups gradually increased in the second intervention month (control group, 31.43%; case group 1, 38.74%; case group 2, 40.19%; case group 3, 52.21%; p < 0.05). After the intervention period, the HHC of case groups 2 and 3 improved significantly from the baseline (23.85% vs. 59.22%, 27.41% vs. 83.62%, respectively; p < 0.05). 'After transferring medical waste from the site' had the highest HHC in case group 3, 90.72% (95% confidence interval, 0.1926-0.3967). HH peak hours were from 6 AM to 9 AM and 2 PM to 3 PM. The study showed that the implementation of an NSM practice can serve as an HHC monitoring indicator and direct relevant training interventions to improve HH among hospital cleaning staff.
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Infecção Hospitalar , Fidelidade a Diretrizes , Desinfecção das Mãos , Higiene das Mãos , Humanos , Infecção Hospitalar/prevenção & controle , Desinfecção das Mãos/métodos , Desinfecção das Mãos/normas , Pessoal de Saúde , Hospitais , Controle de Infecções , Recursos Humanos em HospitalRESUMO
Pentameric ligand-gated ion channels play an important role in mediating fast neurotransmissions. As a member of this receptor family, cation-selective 5-HT3 receptors are a clinical target for treating nausea and vomiting associated with chemotherapy and radiation therapy (Thompson and Lummis, 2006). Multiple cryo-electron microscopy (cryo-EM) structures of 5-HT3 receptors have been determined in distinct functional states (e.g., open, closed, etc.) (Basak et al., 2018; Basak et al., 2018; Polovinkin et al., 2018; Zhang et al., 2015). However, recent work has shown that the transmembrane pores of the open 5-HT3 receptor structures rapidly collapse and become artificially asymmetric in molecular dynamics (MD) simulations. To avoid this hydrophobic collapse, Dämgen and Biggin developed an equilibration protocol that led to a stable open state structure of the glycine receptor in MD simulations (Dämgen and Biggin, 2020). However, the protocol failed to yield open-like structures of the 5-HT3 receptor in our simulations. Here, we present a refined equilibration protocol that involves the rearrangement of the transmembrane helices to achieve stable open state structures of the 5-HT3 receptor that allow both water and ion permeation through the channel. Notably, channel gating is mediated through collective movement of the transmembrane helices, involving not only pore lining M2 helices but also their cross-talk with the adjacent M1 and M3 helices. Thus, the successful application of our refined equilibration protocol underscores the importance of the conformational coupling between the transmembrane helices in stabilizing open-like structures of the 5-HT3 receptor.
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Simulação de Dinâmica Molecular , Serotonina , Serotonina/química , Serotonina/metabolismo , Microscopia Crioeletrônica , Estrutura Secundária de Proteína , Transporte de Íons , Receptores 5-HT3 de Serotonina/química , Receptores 5-HT3 de Serotonina/metabolismoRESUMO
Male infertility caused by genetic mutations is an important type of infertility. Currently, there is no reliable method in the clinic to address this medical need. The emergence of mRNA therapy provides a possible strategy for restoring mutant genes in the reproductive system. However, effective delivery of mRNA to spermatocytes remains a formidable challenge. Here a series of cholesterol-amino-phosphate (CAP) lipids are reported by integrating three bioactive moieties into a geometric structure, which is favorable for mRNA delivery. The results demonstrate that CAP-derived lipid nanoparticles (CAP LNPs) can deliver RNA including traditional mRNA and self-amplifying RNA (saRNA) encoding DNA Meiotic Recombinase 1 (Dmc1) protein in spermatocytes and treat male infertility caused by the Dmc1 gene mutation. Notably, the delivery efficiency of CAP LNPs is significantly higher than that of the MC3 and ALC-0315 LNPs, which is consistent with the design of CAP molecules. More importantly, a single injection of CAP LNPs-saRNA can produce Dmc1 protein for an extended period, which restores the spermatogenesis in the Dmc1 gene knockout mouse model. Overall, this study proves the concept of LNPs for the delivery of mRNA to spermatocytes, which provides a unique method to probe male infertility caused by the genetic mutation.
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Infertilidade Masculina , RNA , Humanos , Camundongos , Masculino , Animais , Espermatogênese/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Infertilidade Masculina/genética , Infertilidade Masculina/terapia , ColesterolRESUMO
In optical devices such as camera or microscope, an aperture is used to regulate light intensity for imaging. Here we report the discovery and construction of a durable bio-aperture at nanometerscale that can regulate current at the pico-ampere scale. The nano-aperture is made of 12 identical protein subunits that form a 3.6-nm channel with a shutter and "one-way traffic" property. This shutter responds to electrical potential differences across the aperture and can be turned off for double stranded DNA translocation. This voltage enables directional control, and three-step regulation for opening and closing. The nano-aperture was constructed in vitro and purified into homogeneity. The aperture was stable at pH2-12, and a temperature of -85C-60C. When an electrical potential was held, three reproducible discrete steps of current flowing through the channel were recorded. Each step reduced 32% of the channel dimension evident by the reduction of the measured current flowing through the aperture. The current change is due to the change of the resistance of aperture size. The transition between these three distinct steps and the direction of the current was controlled via the polarity of the voltage applied across the aperture. When the C-terminal of the aperture was fused to an antigen, the antibody and antigen interaction resulted in a 32% reduction of the channel size. This phenomenon was used for disease diagnosis since the incubation of the antigen-nano-aperture with a specific cancer antibody resulted in a change of 32% of current. The purified truncated cone-shape aperture automatically self-assembled efficiently into a sheet of the tetragonal array via head-to-tail self-interaction. The nano-aperture discovery with a controllable shutter, discrete-step current regulation, formation of tetragonal sheet, and one-way current traffic provides a nanoscale electrical circuit rectifier for nanodevices and disease diagnosis.
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Biomimética , DNARESUMO
As a key regulator for hormone activity, human aldo-keto reductase family 1 member C3 (AKR1C3) plays crucial roles in the occurrence of various hormone-dependent or independent malignancies. It is a promising target for treating castration-resistant prostate cancer (CRPC). However, the development of AKR1C3 specific inhibitors remains challenging due to the high sequence similarity to its isoform AKR1C2. Here, we performed a combined in silico study to illuminate the inhibitory preference of 3-(3,4-dihydroisoquinolin-2(1H)-ylsulfonyl)benzoic acids for AKR1C3 over AKR1C2, of which compound 38 can achieve up to 5000-fold anti-AKR1C3 selectivity. Our umbrella sampling (US) simulations together with end-point binding free energy calculation MM/GBSA uncover that the high inhibition selectivity originates from the different binding modes, namely "Inward" and "Outward," of this compound series in AKR1C3 and AKR1C2, respectively. In AKR1C3/38, the tetrahydroquinoline moiety of 38 is accommodated inside the SP1 pocket and interacts favorably with surrounding residues, while, in AKR1C2/38, the SP1 pocket is too small to hold the bulky tetrahydroquinoline group that instead moves out of the pocket with 38 transitioning from an "Inward" to an "Outward" state. Further 3D-QSAR and energy decomposition analyses suggest that SP1 in AKR1C3 prefers to bind with a rigid bicyclic moiety and the modification of the R3 group has important implication for the compound's activity. This work is the first attempt to elucidate the selectivity mechanism of inhibitors toward AKR1C3 at the atomic level, which is anticipated to propel the development of next-generation AKR1C3 inhibitors with enhanced efficacy and reduced "off-target" effect for CRPC therapy.
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Hidroxiprostaglandina Desidrogenases , Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Membro C3 da Família 1 de alfa-Ceto Redutase/metabolismo , Hidroxiprostaglandina Desidrogenases/metabolismo , 3-Hidroxiesteroide Desidrogenases/metabolismo , Benzoatos/química , Simulação por Computador , Isoformas de Proteínas , HormôniosRESUMO
COVID-19 has become an unprecedented threat to human health. The SARS-CoV-2 envelope (E) protein plays a critical role in the viral maturation process and pathogenesis. Despite intensive investigation, its structure in physiological conditions remains mysterious: no high-resolution full-length structure is available and only an NMR structure of the transmembrane (TM) region has been determined. Here, we present a refined E protein structure, using molecular dynamics (MD) simulations to investigate its structure and dynamics in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer system. Our initial homology model based upon the SARS-CoV E protein structure is shown to be unstable in the lipid bilayer, and the H3 helices tend to move away from the membrane center to the membrane-water interface. A more stable model was developed by replacing all H3 helices with the fully equilibrated H3 structure sampled in the MD simulations. This refined model exhibited more favorable contacts with lipids and water than the original homology model and induced local membrane curvature, decreasing local lipid order. Interestingly, the pore radius profiles showed that the channel in both homology and refined models remained in a closed state throughout the simulations. We also demonstrated the utility of this structure to develop anti-SARS-CoV-2 drugs by docking a library of FDA-approved, investigational, and experimental drugs to the refined E protein structure, identifying 20 potential channel blockers. This highlights the power of MD simulations to refine low-resolution structures of membrane proteins in a native-like membrane environment, shedding light on the structural features of the E protein and providing a platform for the development of novel antiviral treatments.
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Biomolecular binding relies on specific attractive interactions between two partner molecules, including electrostatics, dispersion, hydrophobicity, and solvation. Assessing the contributions of electrostatic interactions to binding is key to the understanding of ligand binding mechanisms and the design of improved biomolecular binders. For example, nicotine is a well-known agonist of nicotinic acetylcholine receptors (nAChRs), but the molecular mechanisms for the differential action of nicotine on brain and muscle nAChRs remain elusive. In this work, we have chosen the acetylcholine binding protein (AChBP) in complex with nicotine as a model system to interrogate the electrostatic contributions to nicotine binding. Our absolute binding free energy simulations confirm that nicotine binds AChBP predominantly in its protonated (charged) form. By comparing energetic contributions from decomposed interactions for either neutral or charged nicotine, our calculations shed light on the nature of the binding of nicotine to the AChBP. The preferred binding of charged nicotine over neutral nicotine originates from its stronger electrostatic interactions with AChBP, a cation-π interaction to a tryptophan residue and a hydrogen bond between nicotine and the backbone carbonyl of the tryptophan, whereas the major force driving the binding process appears to be van der Waals interactions. The various nonelectrostatic terms can also indirectly modulate the electrostatic interactions through fine-tuning the binding pose of the ligand in the binding site, providing an explanation of why the binding specificity of nicotine to the brain versus muscle nAChRs is driven by electrostatic interaction, given that the immediate binding site residues, including the key tryptophan residue, are identical in the two receptors.
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Nicotina , Receptores Nicotínicos , Nicotina/química , Nicotina/metabolismo , Acetilcolina/química , Ligantes , Proteínas de Transporte/química , Eletricidade Estática , Triptofano/química , Modelos Moleculares , Receptores Nicotínicos/química , Sítios de Ligação , Ligação ProteicaRESUMO
Organophosphorus (OP) compounds, including nerve agents and some pesticides, covalently bind to the catalytic serine of human acetylcholinesterase (hAChE), thereby inhibiting acetylcholine hydrolysis necessary for efficient neurotransmission. Oxime antidotes can reactivate the OP-conjugated hAChE, but reactivation efficiency can be low for pesticides, such as paraoxon (POX). Understanding structural and dynamic determinants of OP inhibition and reactivation can provide insights to design improved reactivators. Here, X-ray structures of hAChE with unaged POX, with POX and oximes MMB4 and RS170B, and with MMB4 are reported. A significant conformational distortion of the acyl loop was observed upon POX binding, being partially restored to the native conformation by oximes. Neutron vibrational spectroscopy combined with molecular dynamics simulations showed that picosecond vibrational dynamics of the acyl loop soften in the â¼20-50 cm-1 frequency range. The acyl loop structural perturbations may be correlated with its picosecond vibrational dynamics to yield more comprehensive template for structure-based reactivator design.
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Acetilcolinesterase , Praguicidas , Humanos , Acetilcolinesterase/química , Paraoxon/química , Cristalografia por Raios X , Inibidores da Colinesterase/química , Oximas/química , Compostos Organofosforados , NêutronsRESUMO
Toll-like receptors (TLRs) and CD40-related signaling pathways represent critical bridges between innate and adaptive immune responses. Here, an immunotherapy regimen that enables co-stimulation of TLR7/8- and CD40-mediated pathways is developed. TLR7/8 agonist resiquimod (R848) derived amino lipids, RAL1 and RAL2, are synthesized and formulated into RAL-derived lipid nanoparticles (RAL-LNPs). The RAL2-LNPs show efficient CD40 mRNA delivery to DCs both in vitro (90.8 ± 2.7%) and in vivo (61.3 ± 16.4%). When combined with agonistic anti-CD40 antibody, this approach can produce effective antitumor activities in mouse melanoma tumor models, thereby suppressing tumor growth, prolonging mouse survival, and establishing antitumor memory immunity. Overall, RAL2-LNPs provide a novel platform toward cancer immunotherapy by integrating innate and adaptive immunity.
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Melanoma , Nanopartículas , Receptor 7 Toll-Like , Animais , Camundongos , Adjuvantes Imunológicos , Antígenos CD40 , Imunoterapia , Camundongos Endogâmicos C57BL , Receptor 7 Toll-Like/agonistas , Receptores Toll-Like , Melanoma/tratamento farmacológicoRESUMO
BACKGROUND AND AIM: Patient deaths are common in the intensive care unit, and a nurse's perception of barriers to and supportive behaviors in end-of-life care varies widely depending upon their cultural background. The aim of this study was to describe the perceptions of intensive care nurses regarding barriers to and supportive behaviors in providing end-of-life care in a Chinese cultural context. METHODS: A cross-sectional survey was conducted among intensive care nurses in 20 intensive care units in 11 general hospitals in central and eastern China. Instruments used in this study were general survey and Beckstrand's questionnaire. Data were collected via online survey platform. Descriptive analysis was used to describe general characteristics of participants and mean and standard deviations of the barriers and supportive behaviors. The mean and standard deviation were used to describe the intensity and frequency of each barrier or supportive behavior following Beckstrand's method to calculate the score of barriers and supportive behaviors. Content analysis was used to analyze the responses to open-ended questions. RESULTS: The response rate was 53% (n = 368/700). Five of the top six barriers related to families and the other was the nurse's lack of time. Supportive behaviors included three related to families and three related to healthcare providers. Nurses in the intensive care unit felt that families should be present at the bedside of a dying patient, there is a need to provide a quiet, independent environment and psychological support should be provided to the patient and family. Nurses believe that if possible, families can be given flexibility to visit dying patients, such as increasing the number of visits, rather than limiting visiting hours altogether. Families need to be given enough time to perform the final rites on the dying patient. Moreover, it is remarkable that nurses' supportive behaviors almost all concern care after death. CONCLUSIONS: According to ICU-nurses family-related factors, such as accompany of the dying patients and acceptence of patient's imminent death, were found the major factors affecting the quality of end-of-life care. These findings identify the most prominent current barriers and supportive behaviors, which may provide a basis for addressing these issues in the future to improve the quality of end-of-life care.
Assuntos
Enfermeiras e Enfermeiros , Assistência Terminal , Atitude do Pessoal de Saúde , Cuidados Críticos/psicologia , Estudos Transversais , Humanos , Unidades de Terapia Intensiva , Inquéritos e Questionários , Assistência Terminal/métodosRESUMO
Tumorigenesis is associated with elevated glucose and glutamine consumption, but how cancer cells can sense their levels to activate lipid synthesis is unknown. Here, we reveal that ammonia, released from glutamine, promotes lipogenesis via activation of sterol regulatory element-binding proteins (SREBPs), endoplasmic reticulum-bound transcription factors that play a central role in lipid metabolism. Ammonia activates the dissociation of glucose-regulated, N-glycosylated SREBP-cleavage-activating protein (SCAP) from insulin-inducible gene protein (Insig), an endoplasmic reticulum-retention protein, leading to SREBP translocation and lipogenic gene expression. Notably, 25-hydroxycholesterol blocks ammonia to access its binding site on SCAP. Mutating aspartate D428 to alanine prevents ammonia binding to SCAP, abolishes SREBP-1 activation and suppresses tumour growth. Our study characterizes the unknown role, opposite to sterols, of ammonia as a key activator that stimulates SCAP-Insig dissociation and SREBP-1 activation to promote tumour growth and demonstrates that SCAP is a critical sensor of glutamine, glucose and sterol levels to precisely control lipid synthesis.