Background Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described. MethodsIn this retrospective, multicentre cohort study, we included all adult inpatients (≥18 years old) with laboratoryconfirmed COVID-19 from Jinyintan Hospital and Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or had died by Jan 31, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with in-hospital death. Findings 191 patients (135 from Jinyintan Hospital and 56 from Wuhan Pulmonary Hospital) were included in this study, of whom 137 were discharged and 54 died in hospital. 91 (48%) patients had a comorbidity, with hypertension being the most common (58 [30%] patients), followed by diabetes (36 [19%] patients) and coronary heart disease (15 [8%] patients).Multivariable regression showed increasing odds of in-hospital death associated with older age (odds ratio 1·10, 95% CI 1·03-1·17, per year increase; p=0·0043), higher Sequential Organ Failure Assessment (SOFA) score (5·65, 2·61-12·23; p<0·0001), and d-dimer greater than 1 µg/mL (18·42, 2·64-128·55; p=0·0033) on admission. Median duration of viral shedding was 20·0 days (IQR 17·0-24·0) in survivors, but SARS-CoV-2 was detectable until death in non-survivors. The longest observed duration of viral shedding in survivors was 37 days.Interpretation The potential risk factors of older age, high SOFA score, and d-dimer greater than 1 µg/mL could help clinicians to identify patients with poor prognosis at an early stage. Prolonged viral shedding provides the rationale for a strategy of isolation of infected patients and optimal antiviral interventions in the future.

BACKGROUNDNo therapeutics have yet been proven effective for the treatment of severe illness caused by SARS-CoV-2. METHODSWe conducted a randomized, controlled, open-label trial involving hospitalized adult patients with confirmed SARS-CoV-2 infection, which causes the respiratory illness Covid-19, and an oxygen saturation (Sao 2 ) of 94% or less while they were breathing ambient air or a ratio of the partial pressure of oxygen (Pao 2 ) to the fraction of inspired oxygen (Fio 2 ) of less than 300 mm Hg. Patients were randomly assigned in a 1:1 ratio to receive either lopinavir-ritonavir (400 mg and 100 mg, respectively) twice a day for 14 days, in addition to standard care, or standard care alone. The primary end point was the time to clinical improvement, defined as the time from randomization to either an improvement of two points on a seven-category ordinal scale or discharge from the hospital, whichever came first. RESULTSA total of 199 patients with laboratory-confirmed SARS-CoV-2 infection underwent randomization; 99 were assigned to the lopinavir-ritonavir group, and 100 to the standard-care group. Treatment with lopinavir-ritonavir was not associated with a difference from standard care in the time to clinical improvement (hazard ratio for clinical improvement, 1.24; 95% confidence interval [CI], 0.90 to 1.72). Mortality at 28 days was similar in the lopinavir-ritonavir group and the standard-care group (19.2% vs. 25.0%; difference, −5.8 percentage points; 95% CI, −17.3 to 5.7). The percentages of patients with detectable viral RNA at various time points were similar. In a modified intention-to-treat analysis, lopinavir-ritonavir led to a median time to clinical improvement that was shorter by 1 day than that observed with standard care (hazard ratio, 1.39; 95% CI, 1.00 to 1.91). Gastrointestinal adverse events were more common in the lopinavir-ritonavir group, but serious adverse events were more common in the standard-care group. Lopinavir-ritonavir treatment was stopped early in 13 patients (13.8%) because of adverse events. CONCLUSIONS

Polycomb group (PcG) proteins are required for normal differentiation and development and are frequently deregulated in cancer. PcG proteins are involved in gene silencing; however, their role in initiation and maintenance of transcriptional repression is not well defined. Here, we show that knockout of the Polycomb repressive complex 2 (PRC2) does not lead to significant gene expression changes in mouse embryonic stem cells (mESCs) and that it is dispensable for initiating silencing of target genes during differentiation. Transcriptional inhibition in mESCs is sufficient to induce genome-wide ectopic PRC2 recruitment to endogenous PcG target genes found in other tissues. PRC2 binding analysis shows that it is restricted to nucleosome-free CpG islands (CGIs) of untranscribed genes. Our results show that it is the transcriptional state that governs PRC2 binding, and we propose that it binds by default to nontranscribed CGI genes to maintain their silenced state and to protect cell identity.

Polycomb repressive complex 1 (PRC1) catalyzes lysine 119 monoubiquitylation on H2A (H2AK119ub1) and regulates pluripotency in embryonic stem cells (ESCs). However, the mechanisms controlling the binding of PRC1 to genomic sites and its catalytic activity are poorly understood. Here, we show that Fbxl10 interacts with Ring1B and Nspc1, forming a noncanonical PRC1 that is required for H2AK119ub1 in mouse ESCs. Genome-wide analyses reveal that Fbxl10 preferentially binds to CpG islands and colocalizes with Ring1B on Polycomb target genes. Notably, Fbxl10 depletion causes a decrease in Ring1B binding to target genes and a major loss of H2AK119ub1. Furthermore, genetic analyses demonstrate that Fbxl10 DNA binding capability and integration into PRC1 are required for H2AK119 ubiquitylation. ESCs lacking Fbxl10, like previously characterized Polycomb mutants, cannot differentiate properly. These results demonstrate that Fbxl10 has a key role in regulating Ring1B recruitment to its target genes and H2AK119 ubiquitylation in ESCs.

The balance between self-renewal and differentiation of adult stem cells is essential for tissue homeostasis. Here we show that in the haematopoietic system this process is governed by polycomb chromobox (Cbx) proteins. Cbx7 is specifically expressed in haematopoietic stem cells (HSCs), and its overexpression enhances self-renewal and induces leukaemia. This effect is dependent on integration into polycomb repressive complex-1 (PRC1) and requires H3K27me3 binding. In contrast, overexpression of Cbx2, Cbx4 or Cbx8 results in differentiation and exhaustion of HSCs. ChIP-sequencing analysis shows that Cbx7 and Cbx8 share most of their targets; we identified approximately 200 differential targets. Whereas genes targeted by Cbx8 are highly expressed in HSCs and become repressed in progenitors, Cbx7 targets show the opposite expression pattern. Thus, Cbx7 preserves HSC self-renewal by repressing progenitor-specific genes. Taken together, the presence of distinct Cbx proteins confers target selectivity to PRC1 and provides a molecular balance between self-renewal and differentiation of HSCs.

BackgroundUse of existing disease severity scores would greatly contribute to risk stratification and rationally resource allocation in COVID-19 pandemic. However, the performance of these scores in COVID-19 hospitalised patients with pneumonia was still unknown.MethodsIn this single center, retrospective study, all hospitalised patients with COVID-19 pneumonia from Wuhan Jin Yin-tan Hospital who had discharged or died as of February 15, 2020 were enrolled. Performance of PSI, CURB-65, A-DROP, CRB-65, SMART-COP, qSOFA and NEWS2 were validated. Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were also estimated.ResultsAmong the 654 patients enrolled, 133 patients died and 521 were discharged. Areas of under curves (AUCs) of A-DROP, CURB-65, PSI, SMART-COP, NEWS2, CRB-65 and qSOFA in the prediction of in-hospital death were 0.87, 0.85, 0.85, 0.84, 0.81, 0.80 and 0.73 respectively.ConclusionADROP is a reliable tool for risk stratification of death in COVID-19 hospitalised patients on admission.

The defective generation or function of regulatory T (Treg) cells in autoimmune disease contributes to chronic inflammation and tissue injury. We report the identification of FoxA1 as a transcription factor in T cells that, after ectopic expression, confers suppressive properties in a newly identified Treg cell population, herein called FoxA1(+) Treg cells. FoxA1 bound to the Pdl1 promoter, inducing programmed cell death ligand 1 (Pd-l1) expression, which was essential for the FoxA1(+) Treg cells to kill activated T cells. FoxA1(+) Treg cells develop primarily in the central nervous system in response to autoimmune inflammation, have a distinct transcriptional profile and are CD4(+)FoxA1(+)CD47(+)CD69(+)PD-L1(hi)FoxP3(-). Adoptive transfer of stable FoxA1(+) Treg cells inhibited experimental autoimmune encephalomyelitis in a FoxA1-and Pd-l1-dependent manner. The development of FoxA1(+) Treg cells is induced by interferon-β (IFN-β) and requires T cell-intrinsic IFN-α/β receptor (Ifnar) signaling, as the frequency of FoxA1(+) Treg cells was reduced in Ifnb(-/-) and Ifnar(-/-) mice. In individuals with relapsing-remitting multiple sclerosis, clinical response to treatment with IFN-β was associated with an increased frequency of suppressive FoxA1(+) Treg cells in the blood. These findings suggest that FoxA1 is a lineage-specification factor that is induced by IFN-β and supports the differentiation and suppressive function of FoxA1(+) Treg cells.

We present an integrated middle-down proteomics platform for sensitive mapping and quantification of coexisting PTMs in large polypeptides (5-7 kDa). We combined an RP trap column with subsequent weak cation exchange-hydrophilic interaction LC interfaced directly to high mass accuracy ESI MS/MS using electron transfer dissociation. This enabled automated and efficient separation and sequencing of hypermodified histone N-terminal tails for unambiguous localization of combinatorial PTMs. We present Histone Coder and IsoScale software to extract, filter, and analyze MS/MS data, including quantification of cofragmenting isobaric polypeptide species. We characterized histone tails derived from murine embryonic stem cells knockout in suppressor of zeste12 (Suz12(-/-) ) and quantified 256 combinatorial histone marks in histones H3, H4, and H2A. Furthermore, a total of 713 different combinatorial histone marks were identified in purified histone H3. We measured a seven-fold reduction of H3K27me2/me3 (where me2 and me3 are dimethylation and trimethylation, respectively) in Suz12(-) (/) (-) cells and detected significant changes of the relative abundance of 16 other single PTMs of histone H3 and other combinatorial marks. We conclude that the inactivation of Suz12 is associated with changes in the abundance of not only H3K27 methylation but also multiple other PTMs in histone H3 tails.