Human Coronavirus Virulence Motifs and Virulence

Trabajo presentado en el XIV International Nidovirus Symposium (Nido2017), celebrado en Kansas City, Missouri (Estados Unidos), del 4 al 9 de junio de 2017We have shown that SARS-CoV E protein is a virulence factor that includes at least two virulence motifs: its ion channel (IC) activity encoded within the transmembrane domain and a PDZ binding motif (PBM) located at its carboxy-terminus. We showed that E protein pathogenicity was caused by the activation of different host signaling pathways. One of them was the activation of inflammasome, a process mediated by the conductance of Ca++ byEprotein IC activity, leading to an increased expression of IL-1beta, TNF-alpha and IL-6 levels. Another signaling pathway implied the activation of a proinflammatory response mediated by NF-kB activation. This activation was a consequence of E protein-syntenin binding mediated by PBM-PDZ interactions. This binding caused an increase of p38MAPK phosphorylation promoting the induction of acute respiratory distress syndrome (ARDS), edema and death of mice infected with a mouse adapted SARS-CoV. The relevance of p38 MAPK activation after infection with the mouse adapted SARS-CoV was confirmed by the protection of mice in the presence of an inhibitor of p38 MAPK, but not in its absence. These results illustrated the identification of an efficient coronavirus (CoV) antiviral. The presence of a virulence factor such as the PBM motif in E protein allows the virus to interact with more than 400 cell proteins containing PDZ motifs, conferring the virus the potential to control a high number of cell-signaling pathways increasing its replication and virulence. In fact, we are analyzing the proteome of the viral PBM-cellular PDZ interactions using system biology approaches. Frequently, the ARDS caused by lung infection with mild respiratory viruses is resolved before it evolves to serious edema. In contrast, after SARS-CoV infection frequently this resolution does not take place. We have shown the binding of E protein to a main mediator of edema resolution, the Na+ /K+ ATPase, and proposed that this may be one of the procedures by which edema recovery is prevented after SARS-CoV infection, either by inhibition of Na+ /K+ ATPase activity or by relocating this enzyme to another subcellular compartment. Deadly human CoVs as SARS- and MERS-CoVs have at least two viral proteins with IC activity and PBM motifs. Studies on the relevance of E and 3a SARS-CoV proteins in replication and virulence, and the interdependence among them have shown that the presence in the virus of at least E or 3a proteins was needed for virus viability. In fact, we have shown that the complementation between E and 3a proteins is mediated by the PBM motifs located at the carboxy-terminus of these proteins. Our studies on the interaction of SARS-CoV and MERS-CoV with the host, and the engineering of reverse genetics systems for each of these viruses, led us to the development of genetically stable vaccine candidates that provided full-protection against the challenge with the homologous virulent virus using mice models

Nature of viruses and pandemics: Coronaviruses

Coronaviruses (CoVs) have the largest genome among RNA viruses and store large amounts of information without genome integration as they replicate in the cell cytoplasm. The replication of the virus is a continuous process, whereas the transcription of the subgenomic mRNAs is a discontinuous one, involving a template switch, which resembles a high frequency recombination mechanism that may favor virus genome variability. The origin of the three deadly human CoVs SARS-CoV, MERS-CoV and SARS-CoV-2 are zoonotic events. SARS-CoV-2 has incorporated in its spike protein a furine proteolytic site that facilitates the activation of the virus in any tissue, making this CoV strain highly polytropic and pathogenic. Using MERS-CoV as a model, a propagation-deficient RNA replicon was generated by removing E protein gene (essential for viral morphogenesis and involved in virulence), and accessory genes 3, 4a, 4b and 5 (responsible for antagonism of the innate immune response) to attenuate the virus: MERS-CoV-Δ[3,4a,4b,5,E]. This RNA replicon is strongly attenuated and elicits sterilizing protection after a single immunization in transgenic mice with the receptor for MERS-CoV, making it a promising vaccine candidate for this virus and an interesting platform for vector-based vaccine development. A strategy could be developed for the design of RNA replicon vaccines for other human pathogenic coronaviruses.This work was supported by grants from the Government of Spain (PID2019-107001RB-I00 AEI/FEDER, UE; SEV 2017-0712 and PIE_INTRAMURAL_LINEA 1-202020E079), the CSIC (PIE_INTRAMURAL-202020E043), the European Commission (ISOLDA_848166 H2020-SC1-2019-Two-Stage-RTD, RIA; MANCO_101003651 H2020-SC1-PHE-CORONAVIRUS-2020 RIA), and the U.S. National Institutes of Health (NIH_2P01AI060699).Peer reviewe

Relapse to smoking during unaided cessation: Clinical, cognitive, and motivational predictors

Rationale: Neurobiological models of addiction suggest that abnormalities of brain reward circuitry distort salience attribution and inhibitory control processes, which in turn contribute to high relapse rates. Objectives: To determine whether impairments of salience attribution and inhibitory control predict relapse in a pharmacologically unaided attempt at smoking cessation. Methods: 141 smokers were assessed on indices of nicotine consumption / dependence (e.g. the FTND, cigarettes per day, salivary cotinine), and three trait impulsivity measures. After overnight abstinence they completed experimental tests of cue reactivity, attentional bias to smoking cues, response to financial reward, motor impulsiveness, and response inhibition (antisaccades). They then started a quit attempt with follow-up after 7 days, 1 month, and 3 months; abstinence was verified via salivary cotinine levels ≤ 20ng/ml. Results: Relapse rates at each point were 52.5%, 64% and 76.3%. The strongest predictor was pre-cessation salivary cotinine; other smoking / dependence indices did not explain additional outcome variance and neither did trait impulsivity. All experimental indices except responsivity to financial reward significantly predicted one week outcome. Salivary cotinine, attentional bias to smoking cues and antisaccade errors explained unique as well as shared variance. At one and three months, salivary cotinine, motor impulsiveness and cue reactivity were all individually predictive; the effects of salivary cotinine and motor impulsiveness were additive. Conclusions: These data provide some support for the involvement of abnormal cognitive and motivational processes in sustaining smoking dependence and suggest that they might be a focus of interventions, especially in the early stages of cessation. Dawkins L, Powell JH, Pickering AD, Powell JF, and West RJ (2009) Addiction 104, 850-

Isolation of cross-reactive monoclonal antibodies against divergent human coronaviruses that delineate a conserved and vulnerable site on the spike protein

The coronavirus spike glycoprotein, located on the virion surface, is the key mediator of cell entry. As such, it is an attractive target for the development of protective antibodies and vaccines. Here we describe two human monoclonal antibodies, 1.6C7 and 28D9, that display a remarkable cross-reactivity against distinct species from three Betacoronavirus subgenera, capable of binding the spike proteins of SARS-CoV and SARS-CoV-2, MERS-CoV and the endemic human coronavirus HCoV-OC43. Both antibodies, derived from immunized transgenic mice carrying a human immunoglobulin repertoire, blocked MERS-CoV infection in cells, whereas 28D9 also showed weak cross-neutralizing potential against HCoV-OC43, SARS-CoV and SARS-CoV-2 in a neutralization-sensitive virus pseudotyping system, but not against authentic virus. Both cross-reactive monoclonal antibodies were found to target the stem helix in the spike protein S2 fusion subunit which, in the prefusion conformation of trimeric spike, forms a surface exposed membrane-proximal helical bundle, that is antibody-accessible. We demonstrate that administration of these antibodies in mice protects from a lethal MERS-CoV challenge in both prophylactic and/or therapeutic models. Collectively, these antibodies delineate a conserved, immunogenic and vulnerabe site on the spike protein which spurs the development of broad-range diagnostic, preventive and therapeutic measures against coronaviruses.The project was co-financed by a grant from the Zoonotic Anticipation and Preparedness Initiative [ZAPI project; Innovative Medicines Initiative (IMI) grant agreement no. 115760], with the assistance and financial support of IMI and the European Commission, and in-kind contributions from European Federation of Pharmaceutical Industries and Associations partners. The collaboration project is cofunded by the PPP Allowance made available by Health~Holland, Top Sector Life Sciences & Health, to stimulate public-private partnerships. This study was also partially financed by grants from the Ministry of Science and Innovation of Spain (BIO2016-75549-R AEI/FEDER, UE) and NIH (2PO1AIO6O699). The mice used to generate the mAbs produced in this study were provided by Harbour Antibodies BV, a daughter company of Harbour Biomed (http://www.harbourbiomed.com). Chunyan Wang was supported by a grant from the China Scholarship Council.Peer reviewe

SARS-CoV-2-Mediated Lung Edema and Replication Are Diminished by Cystic Fibrosis Transmembrane Conductance Regulator Modulators

20 Pág.Coronaviruses (CoVs) of genera α, β, γ, and δ encode proteins that have a PDZ-binding motif (PBM) consisting of the last four residues of the envelope (E) protein (PBM core). PBMs may bind over 400 cellular proteins containing PDZ domains (an acronym formed by the combination of the first letter of the names of the three first proteins where this domain was identified), making them relevant for the control of cell function. Three highly pathogenic human CoVs have been identified to date: severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2. The PBMs of the three CoVs were virulence factors. SARS-CoV mutants in which the E protein PBM core was replaced by the E protein PBM core from virulent or attenuated CoVs were constructed. These mutants showed a gradient of virulence, depending on whether the alternative PBM core introduced was derived from a virulent or an attenuated CoV. Gene expression patterns in the lungs of mice infected with SARS-CoVs encoding each of the different PBMs were analyzed by RNA sequencing of infected lung tissues. E protein PBM of SARS-CoV and SARS-CoV-2 dysregulated gene expression related to ion transport and cell homeostasis. Decreased expression of cystic fibrosis transmembrane conductance regulator (CFTR) mRNA, essential for alveolar edema resolution, was shown. Reduced CFTR mRNA levels were associated with edema accumulation in the alveoli of mice infected with SARS-CoV and SARS-CoV-2. Compounds that increased CFTR expression and activity, significantly reduced SARS-CoV-2 growth in cultured cells and protected against mouse infection, suggesting that E protein virulence is mediated by a decreased CFTR expression. IMPORTANCE Three highly pathogenic human CoVs have been identified: SARS-CoV, MERS-CoV, and SARS-CoV-2. The E protein PBMs of these three CoVs were virulence factors. Gene expression patterns associated with the different PBM motifs in the lungs of infected mice were analyzed by deep sequencing. E protein PBM motif of SARS-CoV and SARS-CoV-2 dysregulated the expression of genes related to ion transport and cell homeostasis. A decrease in the mRNA expression of the cystic fibrosis transmembrane conductance regulator (CFTR), which is essential for edema resolution, was observed. The reduction of CFTR mRNA levels was associated with edema accumulation in the lungs of mice infected with SARS-CoV-2. Compounds that increased the expression and activity of CFTR drastically reduced the production of SARS-CoV-2 and protected against its infection in a mice model. These results allowed the identification of cellular targets for the selection of antivirals.This work was supported by grants from the Government of Spain (BIO2016-75549-R; PID2019-107001RB-I00 AEI/FEDER, UE; SEV 2017-0712 and PIE_INTRAMURAL_LINEA 1- 202020E079), CSIC (PIE_INTRAMURAL-202020E043), the European Zoonotic Anticipation and Preparedness Initiative (ZAPI) (IMI_JU_115760), the European Commission (H2020-SC1- 2019, ISOLDA Project No. 848166-2), and the U.S. National Institutes of Health (NIH) (2P01AI060699). J.M.H. received a contract from Comunidad de Madrid (Y2020/BIO-6576, COVID-PREclinical-MODels-CM). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. In vivo experiments were performed at INIA-CISA (Madrid, Spain)Peer reviewe

An ACE2-blocking antibody confers broad neutralization and protection against Omicron and other SARS-CoV-2 variants

The ongoing evolution of SARS-CoV-2 has resulted in the emergence of Omicron, which displays striking immune escape potential. Many of its mutations localize to the spike protein ACE2 receptor-binding domain, annulling the neutralizing activity of most therapeutic monoclonal antibodies. Here we describe a receptor-blocking human monoclonal antibody, 87G7, that retains ultrapotent neutralization against SARS-CoV-2 variants including the Alpha, Beta, Gamma, Delta and Omicron (BA.1/BA.2) Variants-of-Concern (VOCs). Structural analysis reveals that 87G7 targets a patch of hydrophobic residues in the ACE2-binding site that are highly conserved in SARS-CoV-2 variants, explaining its broad neutralization capacity. 87G7 protects mice and/or hamsters against challenge with all current SARS-CoV-2 VOCs. Our findings may aid the development of sustainable antibody-based strategies against COVID-19 that are more resilient to SARS-CoV-2 antigenic diversity.The MANCO project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101003651). This work made use of the Dutch national e infrastructure with the support of the SURF Cooperative using grant no. EINF-2453. This research was funded by the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation) - 398066876/GRK 2485/1; BMBF (Federal Ministry of Education and Research) project entitled RAPID (Risk assessment in re-pandemic respiratory infectious diseases), 01KI1723G, Ministry of Science and Culture of Lower Saxony in Germany (14 - 76103-184 CORONA-15/20)N

Preclinical and randomized phase I studies of plitidepsin in adults hospitalized with COVID-19

Plitidepsin, a marine-derived cyclic-peptide, inhibits SARS-CoV-2 replication at nanomolar concentrations by targeting the host protein eukaryotic translation elongation factor 1A. Here, we show that plitidepsin distributes preferentially to lung over plasma, with similar potency against across several SARS-CoV-2 variants in preclinical studies. Simultaneously, in this randomized, parallel, open-label, proof-of-concept study (NCT04382066) conducted in 10 Spanish hospitals between May and November 2020, 46 adult hospitalized patients with confirmed SARS-CoV-2 infection received either 1.5 mg (n = 15), 2.0 mg (n = 16), or 2.5 mg (n = 15) plitidepsin once daily for 3 d. The primary objective was safety; viral load kinetics, mortality, need for increased respiratory support, and dose selection were secondary end points. One patient withdrew consent before starting procedures; 45 initiated treatment; one withdrew because of hypersensitivity. Two Grade 3 treatment-related adverse events were observed (hypersensitivity and diarrhea). Treatment-related adverse events affecting more than 5% of patients were nausea (42.2%), vomiting (15.6%), and diarrhea (6.7%). Mean viral load reductions from baseline were 1.35, 2.35, 3.25, and 3.85 log10 at days 4, 7, 15, and 31. Nonmechanical invasive ventilation was required in 8 of 44 evaluable patients (16.0%); six patients required intensive care support (13.6%), and three patients (6.7%) died (COVID-19-related). Plitidepsin has a favorable safety profile in patients with COVID-19.This work was supported by grants from the Government of Spain (PIE_INTRAMURAL_ LINEA 1 - 202020E079; PIE_INTRAMURAL_CSIC-202020E043). The research of CBIG consortium (constituted by IRTA-CReSA, BSC, & IrsiCaixa) is supported by Grifols pharmaceutical. We also acknowledge the crowdfunding initiative #Yomecorono (https://www.yomecorono.com). N Izquierdo-Useros has nonrestrictive funding from PharmaMar to study the antiviral effect of Plitidepsin. NJ Krogan was funded by grants from the National Institutes of Health (P50AI150476, U19AI135990, U19AI135972, R01AI143292, R01AI120694, and P01AI063302); by the Excellence in Research Award (ERA) from the Laboratory for Genomics Research (LGR), a collaboration between the University of California, San Francisco (UCSF), University of California, Berkley (UCB), and GlaxoSmithKline (GSK) (#133122P); by the Roddenberry Foundation, and gifts from QCRG philanthropic donors. This work was supported by the Defense Advanced Research Projects Agency (DARPA) under Cooperative Agreement #HR0011-19-2-0020. The views, opinions, and/or findings contained in this material are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. This research was partly funded by Center for Research for Influenza Pathogenesis and Transmission (CRIPT), a National Institute of Allergy and Infectious Diseases (NIAID) supported Center of Excellence for Influenza Research and Response (CEIRS, contract # 75N93021C00014), by DARPA grant HR0011-19-2-0020, by supplements to NIAID grants U19AI142733, U19AI135972, and DoD grant W81XWH-20-1-0270, and by the generous support of the JPB Foundation, the Open Philanthropy Project (research grant 2020-215611 (5384)), and anonymous donors to A García-Sastre. S Yildiz received funding from a Swiss National Foundation Early Postdoc Mobility fellowship (P2GEP3_184202).Peer reviewe