Explore the vast range of titles available.

De novo protein design has enabled the creation of new protein structures. However, the design of functional proteins has proved challenging, in part due to the difficulty of transplanting structurally complex functional sites to available protein structures. Here, we used a bottom-up approach to build de novo proteins tailored to accommodate structurally complex functional motifs. We applied the bottom-up strategy to successfully design five folds for four distinct binding motifs, including a bifunctionalized protein with two motifs. Crystal structures confirmed the atomic-level accuracy of the computational designs. These de novo proteins were functional as components of biosensors to monitor antibody responses and as orthogonal ligands to modulate synthetic signaling receptors in engineered mammalian cells. Our work demonstrates the potential of bottom-up approaches to accommodate complex structural motifs, which will be essential to endow de novo proteins with elaborate biochemical functions, such as molecular recognition or catalysis. Beginning with a functional site and building a supporting scaffold around it enables the de novo design of proteins with distinct binding motifs for use in biosensors to detect antibody responses and as ligands of synthetic signaling receptors.

Remifentanil, a widely used ultra-short-acting μ-opioid receptor agonist in clinical anesthesia, is strongly associated with postoperative hyperalgesia (remifentanil-induced hyperalgesia, RIH), posing significant challenges to postoperative pain management. RIH is characterized by an abnormally heightened pain perception following opioid withdrawal, and its underlying mechanisms are complex and multifactorial. Current research highlights the roles of central sensitization, peripheral sensitization, and multiple interacting molecular pathways. These include NMDA receptor activation, glial cell activation, neuroinflammation, disinhibition of inhibitory neurotransmission, and dysfunction of the descending pain modulation system. Additionally, alterations in ion channel expression, synaptic plasticity enhancement, and peripheral responses to inflammatory mediators contribute critically to RIH development. Individual factors such as age, sex, genetic polymorphisms, and surgical type significantly influence the risk of RIH. Although substantial progress has been made in elucidating the molecular mechanisms of RIH, a unified theoretical framework and effective clinical strategies remain lacking. Future studies should emphasize multi-omics approaches and clinically relevant experimental models to uncover key regulatory targets and provide a theoretical basis for individualized analgesic interventions.

Objective: Cardiovascular disease (CVD) is the leading cause of death among patients with non-alcoholic fatty liver disease (NAFLD). This study investigates the association between high-sensitivity cardiac troponin (hs-cTn) levels and mortality in adults at risk of NAFLD in a representative U.S. population sample. Methods: Among participants aged 18 years and older in the 1999–2004 National Health and Nutrition Examination Survey, we measured high-sensitivity troponin T using a single assay (Roche) and high-sensitivity troponin I using three assays (Abbott, Siemens, and Ortho). Myocardial injury was identified by elevated levels of hs-cTn. Mortality outcomes were determined through linkage with the National Death Index database, with follow-up until December 31, 2019. A multivariable Cox proportional hazards model was used to evaluate the associations between myocardial injury and mortality in the NAFLD population. Sensitivity analyses were conducted to assess the robustness of the main findings. Results: A total of 2581 at risk of NAFLD were included in this observational study, with myocardial injury identified in 7.01%. Over a median follow-up of 16.7 years, 937 all-cause deaths occurred, including 319 cardiovascular disease-related deaths. NAFLD individuals with myocardial injury had worse survival rates at 5, 10, and 15 years compared to those without myocardial injury. After adjusting for baseline characteristics, myocardial injury was associated with an increased risk of all-cause mortality (adjusted Hazard Ratio [aHR] 1.785, 95% CI 1.494–2.134, P < 0.001) and cardiovascular mortality (aHR 2.155, 95% CI 1.606–2.893, P < 0.001). Conclusion: This large, nationally representative study demonstrates that myocardial injury, defined by elevated hs-cTn levels, is independently associated with increased all-cause and cardiovascular mortality risks in the adult population at risk of NAFLD in the United States. This association persisted after adjusting for various factors and in patients without pre-existing cardiovascular disease. The Siemens hs-cTn I assay demonstrated the strongest association with all-cause mortality. These findings highlight the potential of hs-cTn as a valuable prognostic marker in NAFLD patients, even in those without clinically apparent cardiovascular disease. Routine hs-cTn assessment may aid in risk stratification and guide targeted interventions to reduce mortality risk in this population.

Enveloped viruses have evolved complex glycoprotein machinery that drives the fusion of viral and cellular membranes, permitting entry of the viral genome into the cell. For the paramyxoviruses, the fusion (F) protein catalyses this membrane merger and entry step, and it has been postulated that the F protein undergoes complex refolding during this process. Here we report the crystal structure of the parainfluenza virus 5 F protein in its prefusion conformation, stabilized by the addition of a carboxy-terminal trimerization domain. The structure of the F protein shows that there are profound conformational differences between the pre- and postfusion states, involving transformations in secondary and tertiary structure. The positions and structural transitions of key parts of the fusion machinery, including the hydrophobic fusion peptide and two helical heptad repeat regions, clarify the mechanism of membrane fusion mediated by the F protein. Viral membrane fusion Infection of a cell by enveloped viruses such as influenza, HIV and paramyxoviruses requires the fusion of viral and cellular membranes. Many of the viral proteins involved in this process are highly specialized. At first they adopt a metastable shape that stores the energy needed for entry into cells, then irreversible changes in the protein shape catalyse membrane fusion. The crystal structure of pre-fusion parainfluenza virus 5 F fusion protein has now been determined. The extensive differences between pre- and post-fusion states reveal details of the mechanism of membrane fusion which could be of value for developing novel approaches to preventing viral infections.

AbstractThe advertising revenue of online shopping platforms comes from the users who click on the advertisements and purchases the advertised goods. Therefore, to accurately advertise and increase revenue, advertising analysts engage in discovering representative groups and their behavior patterns from the data of demographic attributes, shopping behaviors, and advertising click behaviors of a large number of users. Existing methods often represent user behaviors based on single-level user profiles. However, under different community granularity and time scales, user behaviors have different characteristics. In addition, the sequential relationship between advertisement clicks and other shopping behaviors is difficult to be accurately identified by the single-level analysis methods. Therefore, we cooperate with advertising experts and propose a multi-level visual analysis method based on the K-Means algorithm, which can better understand user behaviors from multiple community granularity and multiple time scales. We design two novel visualization diagrams and improve three traditional charts that can help analysts observe user characteristics at the three levels: user groups, user subgroups, and user individuals, as well as can analyze the time-series events such as advertising clicks and product purchases of representative users from multiple time scales. Furthermore, we implement a multi-view interactive prototype system MulUBA to help analysts put targeted advertisements and increase advertising revenue. Finally, we verify the effectiveness and usability of our approach by conducting three case studies and an expert evaluation on a real-world online shopping advertising dataset.Graphic abstract

Preterm premature rupture of membranes (PROM) is a major cause of extremely preterm birth. Intrauterine infection and inflammation markedly increase the risk of neonatal acute respiratory distress syndrome (NARDS), particularly moderate or severe cases associated with poor outcomes. This study developed and validated a prediction model for moderate or severe NARDS in this population using inflammatory biomarkers. This single center retrospective cohort study included 243 extremely preterm infants with PROM from 2015 to 2024. The primary outcome was moderate or severe NARDS occurring within 72 hours after delivery, diagnosed according to Montreux criteria. Patients were grouped by NARDS severity. Predictive variables were screened using LASSO regression and incorporated into a multivariable logistic model to build a nomogram. Model performance was assessed through receiver operating characteristic curves (ROC), calibration plots and decision curve analysis (DCA). The primary outcome incidence was 20.2% (49/243). Multivariable analysis identified elevated C-reactive protein (CRP) (OR=1.04, 95% CI:1.01-1.07), decreased platelet count (OR=0.99, 95% CI:0.988-0.998), decreased albumin (OR=0.87, 95% CI:0.80-0.95), and decreased arterial pH (OR=0.01, 95% CI:0.001-0.041) as independent predictors. The nomogram integrating these four parameters demonstrated excellent discrimination with an area under the curve (AUC) of 0.824. Internal validation demonstrated good robustness (C-index=0.795). To enhance clinical translation, we developed an interactive web calculator for real time risk assessment to guide pediatricians' clinical decision making. DCA established a 30% risk threshold to inform early interventions. The validated model containing CRP, platelets, albumin and pH effectively identifies high risk PROM infants. The web based interface enables practical bedside application for early detection of critical cases. Patients with predicted probabilities reaching 30% should be considered for preventive lung protection measures. Additional multicenter studies are needed to verify wider applicability and enhance clinical implementation protocols.

Palivizumab was the first antiviral monoclonal antibody (mAb) approved for therapeutic use in humans, and remains a prophylactic treatment for infants at risk for severe disease because of respiratory syncytial virus (RSV). Palivizumab is an engineered humanized version of a murine mAb targeting antigenic site II of the RSV fusion (F) protein, a key target in vaccine development. There are limited reported naturally occurring human mAbs to site II; therefore, the structural basis for human antibody recognition of this major antigenic site is poorly understood. Here, we describe a nonneutralizing class of site II-specific mAbs that competed for binding with palivizumab to postfusion RSV F protein. We also describe two classes of site II-specific neutralizing mAbs, one of which escaped competition with nonneutralizing mAbs. An X-ray crystal structure of the neutralizing mAb 14N4 in complex with F protein showed that the binding angle at which human neutralizing mAbs interact with antigenic site II determines whether or not nonneutralizing antibodies compete with their binding. Fine-mapping studies determined that nonneutralizing mAbs that interfere with binding of neutralizing mAbs recognize site II with a pose that facilitates binding to an epitope containing F surface residues on a neighboring protomer. Neutralizing antibodies, like motavizumab and a new mAb designated 3J20 that escape interference by the inhibiting mAbs, avoid such contact by binding at an angle that is shifted away from the nonneutralizing site. Furthermore, binding to rationally and computationally designed site II helix–loop–helix epitope-scaffold vaccines distinguished neutralizing from nonneutralizing site II antibodies.

Class I viral fusion proteins share common mechanistic and structural features but little sequence similarity. Structural insights into the protein conformational changes associated with membrane fusion are based largely on studies of the influenza virus hemagglutinin in pre- and postfusion conformations. Here, we present the crystal structure of the secreted, uncleaved ectodomain of the paramyxovirus, human parainfluenza virus 3 fusion (F) protein, a member of the class I viral fusion protein group. The secreted human parainfluenza virus 3 F forms a trimer with distinct head, neck, and stalk regions. Unexpectedly, the structure reveals a six-helix bundle associated with the postfusion form of F, suggesting that the anchor-minus ectodomain adopts a conformation largely similar to the postfusion state. The transmembrane anchor domains of F may therefore profoundly influence the folding energetics that establish and maintain a metastable, prefusion state.

Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are two closely related viruses that cause bronchiolitis and pneumonia in infants and the elderly 1 , with a significant health burden 2 – 6 . There are no licensed vaccines or small-molecule antiviral treatments specific to these two viruses at present. A humanized murine monoclonal antibody (palivizumab) is approved to treat high-risk infants for RSV infection 7 , 8 , but other treatments, as well as vaccines, for both viruses are still in development. Recent epidemiological modelling suggests that cross-immunity between RSV, HMPV and human parainfluenzaviruses may contribute to their periodic outbreaks 9 , suggesting that a deeper understanding of host immunity to these viruses may lead to enhanced strategies for their control. Cross-reactive neutralizing antibodies to the RSV and HMPV fusion (F) proteins have been identified 10 , 11 . Here, we examine the structural basis for cross-reactive antibody binding to RSV and HMPV F protein by two related, independently isolated antibodies, MPE8 and 25P13. We solved the structure of the MPE8 antibody bound to RSV F protein and identified the 25P13 antibody from an independent blood donor. Our results indicate that both antibodies use germline residues to interact with a conserved surface on F protein that could guide the emergence of cross-reactivity. The induction of similar cross-reactive neutralizing antibodies using structural vaccinology approaches could enhance intrinsic cross-immunity to these paramyxoviruses and approaches to controlling recurring outbreaks. Examination of the structural basis for cross-reactive antibody binding to RSV and HMPV F protein by two related, independently isolated antibodies indicates that both antibodies interact with a conserved surface that could guide the emergence of cross-reactivity.

Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are paramyxoviruses that are responsible for substantial human health burden, particularly in children and the elderly. The fusion (F) glycoproteins are major targets of the neutralizing antibody response and studies have mapped dominant antigenic sites in F. Here we grafted a major neutralizing site of RSV F, recognized by the prophylactic monoclonal antibody palivizumab, onto HMPV F, generating a chimeric protein displaying epitopes of both viruses. We demonstrate that the resulting chimeric protein (RPM-1) is recognized by both anti-RSV and anti-HMPV F neutralizing antibodies indicating that it can be used to map the epitope specificity of antibodies raised against both viruses. Mice immunized with the RPM-1 chimeric antigen generate robust neutralizing antibody responses to MPV but weak or no cross-reactive recognition of RSV F, suggesting that grafting of the single palivizumab epitope stimulates a comparatively limited antibody response. The RPM-1 protein provides a new tool for characterizing the immune responses resulting from RSV and HMPV infections and provides insights into the requirements for developing a chimeric subunit vaccine that could induce robust and balanced immunity to both virus infections.