Potent and selective covalent inhibition of the papain-like protease from SARS-CoV-2

Direct-acting antivirals are needed to combat coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). The papain-like protease (PLpro) domain of Nsp3 from SARS-CoV-2 is essential for viral replication. In addition, PLpro dysregulates the host immune response by cleaving ubiquitin and interferon-stimulated gene 15 protein from host proteins. As a result, PLpro is a promising target for inhibition by small-molecule therapeutics. Here we design a series of covalent inhibitors by introducing a peptidomimetic linker and reactive electrophile onto analogs of the noncovalent PLpro inhibitor GRL0617. The most potent compound inhibits PLpro with kinact/KI = 9,600 M−1 s−1, achieves sub-μM EC50 values against three SARS-CoV-2 variants in mammalian cell lines, and does not inhibit a panel of human deubiquitinases (DUBs) at >30 μM concentrations of inhibitor. An X-ray co-crystal structure of the compound bound to PLpro validates our design strategy and establishes the molecular basis for covalent inhibition and selectivity against structurally similar human DUBs. These findings present an opportunity for further development of covalent PLpro inhibitors

Potent and selective covalent inhibition of the papain-like protease from SARS-CoV-2

The development of direct-acting antivirals to combat COVID-19 remains an important goal. Here the authors design covalent inhibitors that target the papain-like protease from SARS-CoV-2. The most promising inhibitor blocks viral replication in mammalian cells

Relationships between work outcomes, work attitudes and work environments of health support workers in Ontario long-term care and home and community care settings

Abstract Background Our overarching study objective is to further our understanding of the work psychology of Health Support Workers (HSWs) in long-term care and home and community care settings in Ontario, Canada. Specifically, we seek novel insights about the relationships among aspects of these workers’ work environments, their work attitudes, and work outcomes in the interests of informing the development of human resource programs to enhance elder care. Methods We conducted a path analysis of data collected via a survey administered to a convenience sample of Ontario HSWs engaged in the delivery of elder care over July–August 2015. Results HSWs’ work outcomes, including intent to stay, organizational citizenship behaviors, and performance, are directly and significantly related to their work attitudes, including job satisfaction, work engagement, and affective organizational commitment. These in turn are related to how HSWs perceive their work environments including their quality of work life (QWL), their perceptions of supervisor support, and their perceptions of workplace safety. Conclusions HSWs’ work environments are within the power of managers to modify. Our analysis suggests that QWL, perceptions of supervisor support, and perceptions of workplace safety present particularly promising means by which to influence HSWs’ work attitudes and work outcomes. Furthermore, even modest changes to some aspects of the work environment stand to precipitate a cascade of positive effects on work outcomes through work attitudes

L’année 2021 dans tous ses états : une synthèse digérée

International audience5548 Background: Ovarian cancer is the leading cause of death by gynecological cancer. Complete surgery remains one of the main prognostic factors. Laparoscopic exploration is mandatory to assess surgical resectability at diagnosis or after neoadjuvant chemotherapy. However, there is no clinical or biological marker that can correctly predict resectability and may be able to avoid a second laparoscopic exploration for initially unresectable diseases. Our aim was to assess circulating tumor DNA (ctDNA) value as a predictive non-invasive marker of evolution towards resectability for patients with epithelial ovarian cancer receiving first-line chemotherapy. Methods: We explored in this work one of the secondary objectives of the CIDOC study (NCT03302884). CIDOC is a multicenter prospective study aiming to explore ctDNA value as early marker of disease relapse after first-line treatment for epithelial ovarian cancer. Patients with mucinous histology or early stages not requiring chemotherapy are excluded. Plasma samples are collected at diagnosis, during neoadjuvant chemotherapy, and during follow-up. After DNA extraction, panel-based next generation sequencing is performed on both tumor samples and germline DNA, and somatic mutations of interest are selected for ctDNA monitoring. ctDNA analyses are conducted using droplet digital PCR (BioRad QX200) by measuring the variant allele fraction (VAF) of previously identified mutations. Results: This intermediary analysis has included 47 patients diagnosed between March 2017 and December 2019. Median age was 69 years old (48 – 84). Most of the patients had advanced disease (89.4% stage FIGO III or IV), serous histology (94.8%), and high grade tumor (92.3%). Most of the patients underwent complete interval cytoreductive surgery (76.3% vs 17.4% complete upfront surgery). Most of the tumors had TP53 mutations (85.1%), following by alterations involving DNA repair genes (38.3%). Median cell-free DNA concentration at baseline was 0.38 ng/µL (0 – 12.8). ctDNA was identified in 92.1% of patients at baseline with a median VAF of 1.84% (0 – 42.52%). ctDNA VAF was correlated to the peritoneal dissemination ( p= 0.039) assessed with the peritoneal cancer index. ctDNA clearance after preoperative chemotherapy tended to be correlated to achievement of complete interval surgery for patients receiving neoadjuvant chemotherapy ( p= 0.108). Conclusions: ctDNA may be a promising non-invasive marker to assess peritoneal cancer spreading and to predict surgical resectability after neoadjuvant chemotherapy. If confirmed in larger populations, this may enable to avoid additional surgical explorations for patients who remain ctDNA positive after chemotherapy. Clinical trial information: NCT03302884