The SARS-CoV-2 papain-like protease suppresses type I interferon responses by deubiquitinating STING.

The SARS-CoV-2 papain-like protease (PLpro), which has deubiquitinating activity, suppresses the type I interferon (IFN-I) antiviral response. We investigated the mechanism by which PLpro antagonizes cellular antiviral responses. In HEK392T cells, PLpro removed K63-linked polyubiquitin chains from Lys289 of the stimulator of interferon genes (STING). PLpro-mediated deubiquitination of STING disrupted the STING-IKKε-IRF3 complex that induces the production of IFN-ß and IFN-stimulated cytokines and chemokines. In human airway cells infected with SARS-CoV-2, the combined treatment with the STING agonist diABZi and the PLpro inhibitor GRL0617 resulted in the synergistic inhibition of SARS-CoV-2 replication and increased IFN-I responses. The PLpros of seven human coronaviruses (SARS-CoV-2, SARS-CoV, MERS-CoV, HCoV-229E, HCoV-HKU1, HCoV-OC43, and HCoV-NL63) and four SARS-CoV-2 variants of concern (α, ß, γ, and δ) all bound to STING and suppressed STING-stimulated IFN-I responses in HEK293T cells. These findings reveal how SARS-CoV-2 PLpro inhibits IFN-I signaling through STING deubiquitination and a general mechanism used by seven human coronaviral PLpros to dysregulate STING and to facilitate viral innate immune evasion. We also identified simultaneous pharmacological STING activation and PLpro inhibition as a potentially effective strategy for antiviral therapy against SARS-CoV-2.

The substrate selectivity of papain-like proteases from human-infecting coronaviruses correlates with innate immune suppression.

Coronaviruses that can infect humans can cause either common colds (HCoV-NL63, HCoV-229E, HCoV-HKU1, and HCoV-OC43) or severe respiratory symptoms (SARS-CoV-2, SARS-CoV, and MERS-CoV). The papain-like proteases (PLPs) of SARS-CoV, SARS-CoV-2, MERS-CoV, and HCoV-NL63 function in viral innate immune evasion and have deubiquitinating (DUB) and deISGylating activities. We identified the PLPs of HCoV-229E, HCoV-HKU1, and HCoV-OC43 and found that their enzymatic properties correlated with their ability to suppress innate immune responses. A conserved noncatalytic aspartic acid residue was critical for both DUB and deISGylating activities, but the PLPs had differing ubiquitin (Ub) chain cleavage selectivities and binding affinities for Ub, K48-linked diUb, and interferon-stimulated gene 15 (ISG15) substrates. The crystal structure of HKU1-PLP2 in complex with Ub revealed binding interfaces that accounted for the unusually high binding affinity between this PLP and Ub. In cellular assays, the PLPs from the severe disease-causing coronaviruses strongly suppressed innate immune IFN-I and NF-κB signaling and stimulated autophagy, whereas the PLPs from the mild disease-causing coronaviruses generally showed weaker effects on immune suppression and autophagy induction. In addition, a PLP from a SARS-CoV-2 variant of concern showed increased suppression of innate immune signaling pathways. Overall, these results demonstrated that the DUB and deISGylating activities and substrate selectivities of these PLPs differentially contribute to viral innate immune evasion and may affect viral pathogenicity.

Evaluating the Impact of COVID-19 on Hospital Profit Compensation Activities: A Difference-in-Differences Event Study Analysis in China.

The impact of the 2019 coronavirus disease (COVID-19) pandemic is still being revealed, and little is known about the effect of COVID-19-induced outpatient and inpatient losses on hospital operations in many counties. Hence, we aimed to explore whether hospitals adopted profit compensation activities after the 2020 first-wave outbreak of COVID-19 in China. A total of 2,616,589 hospitalization records from 2018, 2019, and 2020 were extracted from 36 tertiary hospitals in a western province in China; we applied a difference-in-differences event study design to estimate the dynamic effect of COVID-19 on hospitalized patients' total expenses before and after the last confirmed case. We found that average total expenses for each patient increased by 8.7% to 16.7% in the first 25 weeks after the city reopened and hospital admissions returned to normal. Our findings emphasize that the increase in total inpatient expenses was mainly covered by claiming expenses from health insurance and was largely driven by an increase in the expenses for laboratory tests and medical consumables. Our study documents that there were profit compensation activities in hospitals after the 2020 first-wave outbreak of COVID-19 in China, which was driven by the loss of hospitalization admissions during this wave outbreak.

Global DSGE Models

We introduce our GDSGE framework and a novel global solution method, called simultaneous transition and policy function iterations (STPFIs), for solving dynamic stochastic general equilibrium models. The framework encompasses many well-known incomplete markets models with highly nonlinear dynamics such as models of financial crises and models with rare disasters including the current COVID-19 pandemic. Using consistency equations, our method is most effective at solving models featuring endogenous state variables with implicit laws of motion such as wealth or consumption shares. Finally, we incorporate this method in an automated and publicly available toolbox that solves many important models in the aforementioned topics, and in many cases, more efficiently and/or accurately than their original algorithms.

A Modified Regimen of 21-day Nab-Paclitaxel Plus Gemcitabine in Locally Advanced or Metastatic Pancreatic Cancer: A Retrospective Real-World Study.

BACKGROUND: It is 1 of the standard treatment options for metastasis pancreatic cancer to receive nab-paclitaxel (125 mg/m2) plus gemcitabine (1000 mg/m2) on days 1, 8 and 15 every 28 days. Some patients showed intolerance and inconvenience to this therapeutic regimen. Thus, we conducted this retrospective real-world study to determine the efficacy and tolerability of a modified 21-day nab-paclitaxel plus gemcitabine (nab-P/Gem) regimen for the first-line treatment of locally advanced or metastatic pancreatic cancer. METHODS: Patients with locally advanced and metastatic pancreatic cancer treated with nab-paclitaxel (125 mg/m2) plus gemcitabine (1000 mg/m2) on days 1 and 8 every 21-day at West China Hospital and Shang Jin Hospital of Sichuan University from Mar 2018 to Dec 2021 were reviewed retrospectively. Clinical characteristics of patients were collected. The progression-free survival, overall survival, objective response rate, disease control rate, and toxicity were evaluated. RESULTS: A total of 113 patients who received the modified regimen of 21-day nab-P/Gem chemotherapy were included. The median overall survival was 9.3 months and the median progression-free survival was 4.4 months. The objective response rate and disease control rate were 18.6% and 56.7%, respectively. The median relative dose intensity for this modified regimen was 65%. The adverse events were mild to moderate, and the most common grade 3 or 4 treatment-related adverse events were neutropenia (21%) and leukopenia (16%). CONCLUSIONS: Our study showed that this modified regimen of 21-day nab-P/Gem for locally advanced and metastatic pancreatic cancer had comparable efficacy and tolerable toxicity. This treatment may provide a considerable option for pancreatic cancer patients who desire a modified schedule. The modified regimen of 21-day nab-P/Gem is also an option worth considering during the coronavirus disease 2019 pandemic for minimizing the number of visits and limiting the risk of exposure.

Effects of hyperventilation with face mask on brain network in patients with epilepsy.

OBJECTIVES: During the ongoing pandemic of COVID-19, wearing face masks was recommended, including patients with epilepsy doing the hyperventilation (HV) test during electroencephalogram (EEG) examination somewhere. However, evidence was still limited about the effect of HV with face mask on cortical excitability of patients with epilepsy. The motivation of this work is to make use of the graph theory of EEG to characterize the cortical excitability of patients with epilepsy when they did HV under the condition wearing a surgical face mask. METHODS: We recruited 19 patients with epilepsy and 17 normal controls. All of participants completed two HV experiments, including HV with face mask (HV+) and HV without a mask (HV). The interval was 30 min and the sequence was random. Each experiment consisted of three segments: resting EEG, EEG of HV, and EEG of post-HV. EEG were recorded successively during each experiment. Participants were asked to evaluate the discomfort degree using a questionnaire when every HV is completed. RESULTS: All of the participants felt more uncomfortable after HV + . Moreover, not only HV decreased small-worldness index in patients with epilepsy, but also HV + significantly increased the clustering coefficient in patients with epilepsy. Importantly, the three-way of Mask*HV*Epilepsy showed interaction in the clustering coefficient in the delta band, as well as in the path length and the small-worldness index in the theta band. CONCLUSIONS: The results of this study indicated that patients with epilepsy showed the increased excitability of brain network during HV + . We should pay more attention to the adverse effect on brain network excitability caused by HV + in patients with epilepsy. In the clinical practice under the COVID-19 pandemic, it is important that the wearing face mask remain cautious for the individuals with epilepsy when they carried out HV behavior such as exercise (e.g., running, etc.).

Analysis of the intestinal microbiota in COVID-19 patients and its correlation with the inflammatory factor IL-18.

The ongoing global pandemic of COVID-19 disease, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), mainly infect lung epithelial cells, and spread mainly through respiratory droplets. However, recent studies showed potential intestinal infection of SARS-CoV-2, implicated the possibility that the intestinal infection of SARS-CoV-2 may correlate with the dysbiosis of gut microbiota, as well as the severity of COVID-19 symptoms. Here, we investigated the alteration of the gut microbiota in COVID-19 patients, as well as analyzed the correlation between the altered microbes and the levels of intestinal inflammatory cytokine IL-18, which was reported to be elevated in the serum of in COVID-19 patients. Comparing with healthy controls or seasonal flu patients, the gut microbiota showed significantly reduced diversity, with increased opportunistic pathogens in COVID-19 patients. Also, IL-18 level was higher in the fecal samples of COVID-19 patients than in those of either healthy controls or seasonal flu patients. Moreover, the IL-18 levels were even higher in the fecal supernatants obtained from COVID-19 patients that tested positive for SARS-CoV-2 RNA than those that tested negative in fecal samples. These results indicate that changes in gut microbiota composition might contribute to SARS-CoV-2-induced production of inflammatory cytokines in the intestine and potentially also to the onset of a cytokine storm.

The complex structure of GRL0617 and SARS-CoV-2 PLpro reveals a hot spot for antiviral drug discovery.

SARS-CoV-2 is the pathogen responsible for the COVID-19 pandemic. The SARS-CoV-2 papain-like cysteine protease (PLpro) has been implicated in playing important roles in virus maturation, dysregulation of host inflammation, and antiviral immune responses. The multiple functions of PLpro render it a promising drug target. Therefore, we screened a library of approved drugs and also examined available inhibitors against PLpro. Inhibitor GRL0617 showed a promising in vitro IC50 of 2.1 µM and an effective antiviral inhibition in cell-based assays. The co-crystal structure of SARS-CoV-2 PLproC111S in complex with GRL0617 indicates that GRL0617 is a non-covalent inhibitor and it resides in the ubiquitin-specific proteases (USP) domain of PLpro. NMR data indicate that GRL0617 blocks the binding of ISG15 C-terminus to PLpro. Using truncated ISG15 mutants, we show that the C-terminus of ISG15 plays a dominant role in binding PLpro. Structural analysis reveals that the ISG15 C-terminus binding pocket in PLpro contributes a disproportionately large portion of binding energy, thus this pocket is a hot spot for antiviral drug discovery targeting PLpro.

Efficacy of chemotherapy combined with toripalimab in PD-L1-positive and high tumor mutation burden pancreatic acinar cell carcinoma: case report.

BACKGROUND: Pancreatic acinar cell carcinoma (PACC) is a rare tumor, accounting for about 1% of all pancreatic exocrine cancers. Consensus on the management of metastatic PACC remains unclear. CASE PRESENTATION: Starting from April 2019, a patient first received chemotherapy with two cycles of gemcitabine and nab-paclitaxel and two cycles of SOX regimen. After progression of disease evaluated based on RECIST 1.1, toripalimab and SOX regimen was administered because of PD-L1-positive expression, high tumor mutation burden (TMB), and somatic FANCA deletion in the tumor. Both the primary and metastatic tumor mass shrank significantly after two courses. The patient exhibited sustained partial response for at least six courses with well-controlled toxic effects. Then the treatment had to be stopped for 2 months because of the coronavirus disease 2019 pandemic. Computed tomography scan in March 2020 showed disease progression. Time from initiating treatment to tumor progression on toripalimab and SOX regimen treatment took up to at least 8 months. CONCLUSIONS: We present the first case report where a PD-L1 positive, high TMB, and FANCA-deleted pancreatic acinar cell carcinoma was treated using chemotherapy combined with immunotherapy, in which the patient exhibited satisfactory response and tolerance.

An inter-correlated cytokine network identified at the center of cytokine storm predicted COVID-19 prognosis.

The hyper-inflammatory response is thought to be a major cause of acute respiratory distress syndrome (ARDS) in patients with COVID-19. Although multiple cytokines are reportedly associated with disease severity, the key mediators of SARS-CoV-2 induced cytokine storm and their predictive values have not been fully elucidated. The present study analyzed maximal and early (within 10 days after disease onset) concentrations of 12-plex cytokines in plasma. We found consistently elevated plasma levels of IL-6, IL-8 and IL-5 in patients who were deceased compared with those who had mild/moderate or severe disease. The early plasma concentrations of IFN-a and IL-2 positively correlated with the length of the disease course. Moreover, correlation network analysis showed that IL-6, IL-8, and IL-5 located at the center of an inter-correlated cytokine network. These findings suggested that IL-8, IL-6, IL-5 might play central roles in cytokine storms associated with COVID-19 and that the early detection of multiple plasma cytokines might help to predict the prognosis of this disease.