Search

Background Patients with critical illness due to infection with the 2019 coronavirus disease (COVID-19) show rapid disease progression to acute respiratory failure. The study aimed to screen the most useful predictive factor for critical illness caused by COVID-19. Methods The study prospectively involved 61 patients with COVID-19 infection as a derivation cohort, and 54 patients as a validation cohort. The predictive factor for critical illness was selected using LASSO regression analysis. A nomogram based on non-specific laboratory indicators was built to predict the probability of critical illness. Results The neutrophil-to-lymphocyte ratio (NLR) was identified as an independent risk factor for critical illness in patients with COVID-19 infection. The NLR had an area under receiver operating characteristic of 0.849 (95% confidence interval [CI], 0.707 to 0.991) in the derivation cohort and 0.867 (95% CI 0.747 to 0.944) in the validation cohort, the calibration curves fitted well, and the decision and clinical impact curves showed that the NLR had high standardized net benefit. In addition, the incidence of critical illness was 9.1% (1/11) for patients aged ≥ 50 and having an NLR Conclusions We found that NLR is a predictive factor for early-stage prediction of patients infected with COVID-19 who are likely to develop critical illness. Patients aged ≥ 50 and having an NLR ≥ 3.13 are predicted to develop critical illness, and they should thus have rapid access to an intensive care unit if necessary.

Introduction Many individuals test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA after recovering from the coronavirus disease (COVID-19), but the incidence of reactivation is unknown. We, therefore, estimated the incidence of reactivation among individuals who had recovered from COVID-19 and determined its predictors. Methods In this retrospective cohort study, patients with COVID-19 were followed up for at least 14 days after two consecutive negative SARS-CoV-2 polymerase chain reaction test results obtained ≥24 hours apart, and the frequency of SARS-CoV-2 reactivation was assessed. Results Of the 109 patients, 29 (27%) experienced reactivation, and seven (24%) of these were symptomatic. The mean period for the real-time PCR tests for SARS-CoV-2 from negative to positive results was 17 days. Compared with patients without reactivation, those with reactivation were significantly younger and more likely to have a lymphocyte count of

We primarily quantified exposure patterns, transmission characteristics, and the clinical spectrum of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection among household contacts of individuals with severe coronavirus disease‐2019 (COVID‐19). We conducted a retrospective cohort study of 20 index patients hospitalized with severe COVID‐19 and 79 of their household contacts. We determined the transmission frequency, range of manifestations of SARS‐CoV‐2 infection, and factors associated with infection in household settings. Of the 79 household contacts, 53 (67%) developed SARS‐CoV‐2 infection (49 [62%] symptomatic, 4 [5%] asymptomatic). Eight patients (10%) developed severe COVID‐19, and one died of COVID‐19 pneumonia (case‐fatality rate: 1.9%). The probability of SARS‐CoV‐2 infection was similar in children and adults (55% vs. 72%, p = .14), with children being less likely to develop the symptomatic disease (46% vs. 68%, p = .06). Handwashing ≥ 5 times/day was associated with reduced infection risk (52.8% vs. 76.9%, p = .04). SARS‐CoV‐2 has a high frequency of transmission among household contacts. Nonhospitalized individuals with SARS‐CoV‐2 infection should be quarantined in patient care facilities rather than at home to minimize spread, if possible, and frequent handwashing should be practiced to prevent transmission., Highlights The new coronavirus, SARS‐CoV‐2, is the cause of the COVID‐19 pandemic. It is readily transmitted and may cause severe pneumonia, but information on its infectivity and the full disease spectrum of the infection is limited because many infections are undiagnosed.The study followed a cohort of 79 household contacts of 20 unrelated index patients with severe COVID‐19 pneumonia. All household contacts had exposure to infection, and the complete cohort was followed‐up; thus, it was possible to determine the rates of transmission and the severity and complete clinical course of all infections. We were also able to determine the risk factors for transmission and severe disease and to compare the susceptibility of children and adults to infection and disease.

Cellular senescence has been proposed to play critical roles in tumor suppression and organismal aging, but the molecular mechanism of senescence remains incompletely understood. Here we report that a putative lysosomal carbohydrate efflux transporter, Spinster, induces cellular senescence in human primary fibroblasts. Administration of d-galactose synergistically enhanced Spinster-induced senescence and this synergism required the transporter activity of Spinster. Intracellular d-galactose is metabolized to galactose-1-phosphate by galactokinase. Galactokinase-deficient fibroblasts, which accumulate intracellular d-galactose, displayed increased baseline senescence. Senescence of galactokinase-deficient fibroblasts was further enhanced by d-galactose administration and was diminished by restoration of wild-type galactokinase expression. Silencing galactokinase in normal fibroblasts also induced senescence. These results suggest a role for intracellular galactose in the induction of cellular senescence.

Cellular senescence has emerged as a critical tumor suppressive mechanism in recent years, but relatively little is known about how senescence occurs. Here, we report that secreted Frizzled-related protein 1 (SFRP1), a secreted antagonist of Wnt signaling, is oversecreted upon cellular senescence caused by DNA damage or oxidative stress. SFRP1 is necessary for stress-induced senescence caused by these factors and is sufficient for the induction of senescence phenotypes. We present evidence suggesting that SFRP1 functions as a secreted mediator of senescence through inhibition of Wnt signaling and activation of the retinoblastoma (Rb) pathway and that cancer-associated SFRP1 mutants are defective for senescence induction.

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor is associated with renal carcinoma, hemangioblastoma and pheochromocytoma. The VHL protein is a component of a ubiquitin ligase complex that ubiquitinates and degrades hypoxia inducible factor-α (HIF-α). Degradation of HIF-α by VHL is proposed to suppress tumorigenesis and tumor angiogenesis. Several lines of evidence also suggest important roles for HIF-independent VHL functions in tumor suppression and other biological processes. Using GST-VHL pull-down experiment and mass spectrometry, we detected an interaction between VHL and heterochromatin protein 1 (HP1). We identified a conserved HP1-binding motif (PXVXL) in the β domain of VHL, which is disrupted in a renal carcinoma-associated P81S mutant. We show that the VHL P81S mutant displays reduced binding to HP1, yet retains the ability to interact with elongin B, elongin C, and cullin 2 and is fully capable of degrading HIF-α. We also demonstrate that HP1 increases the chromatin association of VHL. These results suggest a role for the VHL-HP1 interaction in VHL chromatin targeting.

Mutation of the BRCA1 tumor suppressor gene predisposes women to hereditary breast and ovarian cancers. BRCA1 forms a heterodimer with BARD1. The BRCA1/BARD1 heterodimer has ubiquitin ligase activity, considered to play crucial roles in tumor suppression and DNA damage response. Nevertheless, relevant BRCA1 substrates are poorly defined. We have developed a new approach to systematically identify the substrates of ubiquitin ligases by identifying proteins that display an enhanced incorporation of His-tagged ubiquitin upon ligase coexpression; using this method, we identified several candidate substrates for BRCA1. These include scaffold attachment factor B2 (SAFB2) and Tel2 as well as BARD1. BRCA1 was found to enhance SAFB protein expression and induce Tel2 nuclear translocation. Identification of the ubiquitination substrates has been a major obstacle to understanding the functions of ubiquitin ligases. The quantitative proteomics approach we devised for the identification of BRCA1 substrates will facilitate the identification of ubiquitin ligase-substrate pairs.

Ewing sarcoma is a cancer of bone and soft tissue in children that is characterized by a chromosomal translocation involving EWS and an Ets family transcription factor, most commonly Fli-1. EWS-Fli-1 fusion accounts for 85% of cases. The growth and survival of Ewing sarcoma cells are critically dependent on EWS-Fli-1. A large body of evidence has established that EWS-Fli-1 functions as a DNA-binding transcription factor that regulates the expression of a number of genes important for cell proliferation and transformation. However, little is known about the biochemical properties of the EWS-Fli-1 protein. We undertook a series of proteomic analyses to dissect the EWS-Fli-1 interactome. Employing a proximity-dependent biotinylation technique, BioID, we identified cation-independent mannose 6-phosphate receptor (CIMPR) as a protein located in the vicinity of EWS-Fli-1 within a cell. CIMPR is a cargo that mediates the delivery of lysosomal hydrolases from the trans-Golgi network to the endosome, which are subsequently transferred to the lysosomes. Further molecular cell biological analyses uncovered a role for lysosomes in the turnover of the EWS-Fli-1 protein. We demonstrate that an mTORC1 active-site inhibitor, torin 1, which stimulates the TFEB-lysosome pathway, can induce the degradation of EWS-Fli-1, suggesting a potential therapeutic approach to target EWS-Fli-1 for degradation.

Cellular senescence is widely believed to play a key role in tumor suppression, but the molecular pathways that regulate senescence are only incompletely understood. By using a secretome proteomics approach, we identified insulin-like growth factor binding protein 3 (IGFBP3) as a secreted mediator of breast cancer senescence upon chemotherapeutic drug treatment. The senescence-inducing activity of IGFBP3 is inhibited by tissue-type plasminogen activator-mediated proteolysis, which is counteracted by plasminogen activator inhibitor 1 (PAI-1), another secreted mediator of senescence. We demonstrate that IGFBP3 is a critical downstream target of PAI-1-induced senescence. These results suggest a role for an extracellular cascade of secreted proteins in the regulation of cellular senescence.

Background The von Hippel-Lindau (VHL) tumor suppressor gene encodes a component of a ubiquitin ligase complex, which is best understood as a negative regulator of hypoxia inducible factor (HIF). VHL ubiquitinates and degrades the α subunits of HIF, and this is proposed to suppress tumorigenesis and tumor angiogenesis. However, several lines of evidence suggest that there are unidentified substrates or targets for VHL that play important roles in tumor suppression. Methodology/Principal Findings Employing quantitative proteomics, we developed an approach to systematically identify the substrates of ubiquitin ligases and using this method, we identified the Myb-binding protein p160 as a novel substrate of VHL. Conclusions/Significance A major barrier to understanding the functions of ubiquitin ligases has been the difficulty in pinpointing their ubiquitination substrates. The quantitative proteomics approach we devised for the identification of VHL substrates will be widely applicable to other ubiquitin ligases.