Publications by authors named "Yfat Yahalom-Ronen"

12 Publications

  • Page 1 of 1

Sensitive immunodetection of SARS-CoV-2 variants-of-concern 501Y.V2 and 501Y.V1.

J Infect Dis 2021 May 23. Epub 2021 May 23.

The Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, 7410001, Israel.

Emerging SARS-CoV-2 variants potentially influence the effectiveness of existing laboratory diagnostics. In this study we determined whether the British (20I/501Y.V1) and South-African (20H/501Y.V2) SARS-CoV-2 variants-of-concern (VOC) are detected by an in-house S1-based antigen-detection assay. Analysis was performed in spiked pools of qRT-PCR negative nasopharyngeal swab specimens. The assay, composed of a combination of four monoclonal antibodies, allowed sensitive detection of both the wild-type and the analyzed VOCs, despite the accumulation of several mutations in the variants' S1 region. We suggest that the combination of four monoclonal antibodies, targeting distinct epitopes, maintained both the specificity and the universality of the assay.
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http://dx.doi.org/10.1093/infdis/jiab278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8194863PMC
May 2021

SARS-CoV-2 uses a multipronged strategy to impede host protein synthesis.

Nature 2021 06 12;594(7862):240-245. Epub 2021 May 12.

Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.

The coronavirus SARS-CoV-2 is the cause of the ongoing pandemic of COVID-19. Coronaviruses have developed a variety of mechanisms to repress host mRNA translation to allow the translation of viral mRNA, and concomitantly block the cellular innate immune response. Although several different proteins of SARS-CoV-2 have previously been implicated in shutting off host expression, a comprehensive picture of the effects of SARS-CoV-2 infection on cellular gene expression is lacking. Here we combine RNA sequencing, ribosome profiling and metabolic labelling of newly synthesized RNA to comprehensively define the mechanisms that are used by SARS-CoV-2 to shut off cellular protein synthesis. We show that infection leads to a global reduction in translation, but that viral transcripts are not preferentially translated. Instead, we find that infection leads to the accelerated degradation of cytosolic cellular mRNAs, which facilitates viral takeover of the mRNA pool in infected cells. We reveal that the translation of transcripts that are induced in response to infection (including innate immune genes) is impaired. We demonstrate this impairment is probably mediated by inhibition of nuclear mRNA export, which prevents newly transcribed cellular mRNA from accessing ribosomes. Overall, our results uncover a multipronged strategy that is used by SARS-CoV-2 to take over the translation machinery and to suppress host defences.
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http://dx.doi.org/10.1038/s41586-021-03610-3DOI Listing
June 2021

Glucosylceramide synthase inhibitors prevent replication of SARS-CoV-2 and Influenza virus.

J Biol Chem 2021 Feb 24:100470. Epub 2021 Feb 24.

Departments of Infectious diseases, Israel institute for Biological Research, Ness-Ziona, 7410000, Israel.

The ongoing COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major threat to global health. Vaccines are ideal solutions to prevent infection, but treatments are also needed for those who have contracted the virus to limit negative outcomes, when vaccines are not applicable. Viruses must cross host cell membranes during their lifecycle, creating a dependency on processes involving membrane dynamics. Thus, in this study we examined whether the synthetic machinery for glycosphingolipids, biologically active components of cell membranes, can serve as a therapeutic target to combat SARS-CoV-2. We examined the antiviral effect of two specific inhibitors of glucosylceramide synthase (GCS); (i) Genz-123346, an analogue of the FDA-approved drug Cerdelga®, and (ii) GENZ-667161, an analogue of venglustat which is currently under phase III clinical trials. We found that both GCS inhibitors inhibit replication of SARS-CoV-2. Moreover, these inhibitors also disrupt replication of influenza virus A/PR/8/34 (H1N1). Our data imply that synthesis of glycosphingolipids is necessary to support viral life cycles, and suggest that GCS inhibitors should be further explored as antiviral therapies.
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http://dx.doi.org/10.1016/j.jbc.2021.100470DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904475PMC
February 2021

Design of SARS-CoV-2 hFc-Conjugated Receptor-Binding Domain mRNA Vaccine Delivered Lipid Nanoparticles.

ACS Nano 2021 Jan 22. Epub 2021 Jan 22.

Laboratory of Precision NanoMedicine, Shmunis School for Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the causal agent of COVID-19 and stands at the center of the current global human pandemic, with death toll exceeding one million. The urgent need for a vaccine has led to the development of various immunization approaches. mRNA vaccines represent a cell-free, simple, and rapid platform for immunization, and therefore have been employed in recent studies toward the development of a SARS-CoV-2 vaccine. Herein, we present the design of an mRNA vaccine, based on lipid nanoparticles (LNPs)-encapsulated SARS-CoV-2 human Fc-conjugated receptor-binding domain (RBD-hFc). Several ionizable lipids have been evaluated in a luciferase (luc) mRNA reporter assay, and two leading LNPs formulations have been chosen for the subsequent RBD-hFc mRNA vaccine strategy. Intramuscular administration of LNP RBD-hFc mRNA elicited robust humoral response, a high level of neutralizing antibodies and a Th1-biased cellular response in BALB/c mice. The data in the current study demonstrate the potential of these lipids as promising candidates for LNP-based mRNA vaccines in general and for a COVID19 vaccine in particular.
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http://dx.doi.org/10.1021/acsnano.0c10180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7860138PMC
January 2021

A single dose of recombinant VSV-∆G-spike vaccine provides protection against SARS-CoV-2 challenge.

Nat Commun 2020 12 16;11(1):6402. Epub 2020 Dec 16.

Israel Institute for Biological Research, Ness Ziona, Israel.

The COVID-19 pandemic caused by SARS-CoV-2 imposes an urgent need for rapid development of an efficient and cost-effective vaccine, suitable for mass immunization. Here, we show the development of a replication competent recombinant VSV-∆G-spike vaccine, in which the glycoprotein of VSV is replaced by the spike protein of SARS-CoV-2. In-vitro characterization of this vaccine indicates the expression and presentation of the spike protein on the viral membrane with antigenic similarity to SARS-CoV-2. A golden Syrian hamster in-vivo model for COVID-19 is implemented. We show that a single-dose vaccination results in a rapid and potent induction of SARS-CoV-2 neutralizing antibodies. Importantly, vaccination protects hamsters against SARS-CoV-2 challenge, as demonstrated by the abrogation of body weight loss, and  alleviation of the extensive tissue damage and viral loads in lungs and nasal turbinates. Taken together, we suggest the recombinant VSV-∆G-spike as a safe, efficacious and protective vaccine against SARS-CoV-2.
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http://dx.doi.org/10.1038/s41467-020-20228-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7745033PMC
December 2020

Detection and infectivity potential of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) environmental contamination in isolation units and quarantine facilities.

Clin Microbiol Infect 2020 Dec 10;26(12):1658-1662. Epub 2020 Sep 10.

Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel. Electronic address:

Objectives: Environmental surfaces have been suggested as likely contributors in the transmission of COVID-19. This study assessed the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contaminating surfaces and objects in two hospital isolation units and a quarantine hotel.

Methods: SARS-CoV-2 virus stability and infectivity on non-porous surfaces was tested under controlled laboratory conditions. Surface and air sampling were conducted at two COVID-19 isolation units and in a quarantine hotel. Viral RNA was detected by RT-PCR and infectivity was assessed by VERO E6 CPE test.

Results: In laboratory-controlled conditions, SARS-CoV-2 gradually lost its infectivity completely by day 4 at ambient temperature, and the decay rate of viral viability on surfaces directly correlated with increase in temperature. Viral RNA was detected in 29/55 surface samples (52.7%) and 16/42 surface samples (38%) from the surroundings of symptomatic COVID-19 patients in isolation units of two hospitals and in a quarantine hotel for asymptomatic and very mild COVID-19 patients. None of the surface and air samples from the three sites (0/97) were found to contain infectious titres of SARS-Cov-2 on tissue culture assay.

Conclusions: Despite prolonged viability of SARS-CoV-2 under laboratory-controlled conditions, uncultivable viral contamination of inanimate surfaces might suggest low feasibility for indirect fomite transmission.
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http://dx.doi.org/10.1016/j.cmi.2020.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7481174PMC
December 2020

The coding capacity of SARS-CoV-2.

Nature 2021 01 9;589(7840):125-130. Epub 2020 Sep 9.

Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the ongoing coronavirus disease 2019 (COVID-19) pandemic. To understand the pathogenicity and antigenic potential of SARS-CoV-2 and to develop therapeutic tools, it is essential to profile the full repertoire of its expressed proteins. The current map of SARS-CoV-2 coding capacity is based on computational predictions and relies on homology with other coronaviruses. As the protein complement varies among coronaviruses, especially in regard to the variety of accessory proteins, it is crucial to characterize the specific range of SARS-CoV-2 proteins in an unbiased and open-ended manner. Here, using a suite of ribosome-profiling techniques, we present a high-resolution map of coding regions in the SARS-CoV-2 genome, which enables us to accurately quantify the expression of canonical viral open reading frames (ORFs) and to identify 23 unannotated viral ORFs. These ORFs include upstream ORFs that are likely to have a regulatory role, several in-frame internal ORFs within existing ORFs, resulting in N-terminally truncated products, as well as internal out-of-frame ORFs, which generate novel polypeptides. We further show that viral mRNAs are not translated more efficiently than host mRNAs; instead, virus translation dominates host translation because of the high levels of viral transcripts. Our work provides a resource that will form the basis of future functional studies.
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http://dx.doi.org/10.1038/s41586-020-2739-1DOI Listing
January 2021

A panel of human neutralizing mAbs targeting SARS-CoV-2 spike at multiple epitopes.

Nat Commun 2020 08 27;11(1):4303. Epub 2020 Aug 27.

Israel Institute for Biological Research, Ness-Ziona, Israel.

The novel highly transmissible human coronavirus SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Thus far, there is no approved therapeutic drug specifically targeting this emerging virus. Here we report the isolation and characterization of a panel of human neutralizing monoclonal antibodies targeting the SARS-CoV-2 receptor binding domain (RBD). These antibodies were selected from a phage display library constructed using peripheral circulatory lymphocytes collected from patients at the acute phase of the disease. These neutralizing antibodies are shown to recognize distinct epitopes on the viral spike RBD. A subset of the antibodies exert their inhibitory activity by abrogating binding of the RBD to the human ACE2 receptor. The human monoclonal antibodies described here represent a promising basis for the design of efficient combined post-exposure therapy for SARS-CoV-2 infection.
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http://dx.doi.org/10.1038/s41467-020-18159-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7452893PMC
August 2020

Nkx2.5 marks angioblasts that contribute to hemogenic endothelium of the endocardium and dorsal aorta.

Elife 2017 03 8;6. Epub 2017 Mar 8.

Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.

Novel regenerative therapies may stem from deeper understanding of the mechanisms governing cardiovascular lineage diversification. Using enhancer mapping and live imaging in avian embryos, and genetic lineage tracing in mice, we investigated the spatio-temporal dynamics of cardiovascular progenitor populations. We show that expression of the cardiac transcription factor marks a mesodermal population outside of the cardiac crescent in the extraembryonic and lateral plate mesoderm, with characteristics of hemogenic angioblasts. Extra-cardiac lineage progenitors migrate into the embryo and contribute to clusters of CD41/CD45 and RUNX1 cells in the endocardium, the aorta-gonad-mesonephros region of the dorsal aorta and liver. We also demonstrated that ectopic expression of in chick embryos activates the hemoangiogenic gene expression program. Taken together, we identified a hemogenic angioblast cell lineage characterized by transient expression that contributes to hemogenic endothelium and endocardium, suggesting a novel role for in hemoangiogenic lineage specification and diversification.
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http://dx.doi.org/10.7554/eLife.20994DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5400512PMC
March 2017

Reduced matrix rigidity promotes neonatal cardiomyocyte dedifferentiation, proliferation and clonal expansion.

Elife 2015 Aug 12;4. Epub 2015 Aug 12.

Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.

Cardiomyocyte (CM) maturation in mammals is accompanied by a sharp decline in their proliferative and regenerative potential shortly after birth. In this study, we explored the role of the mechanical properties of the underlying matrix in the regulation of CM maturation. We show that rat and mouse neonatal CMs cultured on rigid surfaces exhibited increased myofibrillar organization, spread morphology, and reduced cell cycle activity. In contrast, compliant elastic matrices induced features of CM dedifferentiation, including a disorganized sarcomere network, rounding, and conspicuous cell-cycle re-entry. The rigid matrix facilitated nuclear division (karyokinesis) leading to binucleation, while compliant matrices promoted CM mitotic rounding and cell division (cytokinesis), associated with loss of differentiation markers. Moreover, the compliant matrix potentiated clonal expansion of CMs that involves multiple cell divisions. Thus, the compliant microenvironment facilitates CM dedifferentiation and proliferation via its effect on the organization of the myoskeleton. Our findings may be exploited to design new cardiac regenerative approaches.
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http://dx.doi.org/10.7554/eLife.07455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4558647PMC
August 2015

ERBB2 triggers mammalian heart regeneration by promoting cardiomyocyte dedifferentiation and proliferation.

Nat Cell Biol 2015 May 6;17(5):627-38. Epub 2015 Apr 6.

Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel.

The murine neonatal heart can regenerate after injury through cardiomyocyte (CM) proliferation, although this capacity markedly diminishes after the first week of life. Neuregulin-1 (NRG1) administration has been proposed as a strategy to promote cardiac regeneration. Here, using loss- and gain-of-function genetic tools, we explore the role of the NRG1 co-receptor ERBB2 in cardiac regeneration. NRG1-induced CM proliferation diminished one week after birth owing to a reduction in ERBB2 expression. CM-specific Erbb2 knockout revealed that ERBB2 is required for CM proliferation at embryonic/neonatal stages. Induction of a constitutively active ERBB2 (caERBB2) in neonatal, juvenile and adult CMs resulted in cardiomegaly, characterized by extensive CM hypertrophy, dedifferentiation and proliferation, differentially mediated by ERK, AKT and GSK3β/β-catenin signalling pathways. Transient induction of caERBB2 following myocardial infarction triggered CM dedifferentiation and proliferation followed by redifferentiation and regeneration. Thus, ERBB2 is both necessary for CM proliferation and sufficient to reactivate postnatal CM proliferative and regenerative potentials.
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http://dx.doi.org/10.1038/ncb3149DOI Listing
May 2015

Nuclear to cytoplasmic shuttling of ERK promotes differentiation of muscle stem/progenitor cells.

Development 2014 Jul 12;141(13):2611-20. Epub 2014 Jun 12.

Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel

The transition between the proliferation and differentiation of progenitor cells is a key step in organogenesis, and alterations in this process can lead to developmental disorders. The extracellular signal-regulated kinase 1/2 (ERK) signaling pathway is one of the most intensively studied signaling mechanisms that regulates both proliferation and differentiation. How a single molecule (e.g. ERK) can regulate two opposing cellular outcomes is still a mystery. Using both chick and mouse models, we shed light on the mechanism responsible for the switch from proliferation to differentiation of head muscle progenitors and implicate ERK subcellular localization. Manipulation of the fibroblast growth factor (FGF)-ERK signaling pathway in chick embryos in vitro and in vivo demonstrated that blockage of this pathway accelerated myogenic differentiation, whereas its activation diminished it. We next examined whether the spatial subcellular localization of ERK could act as a switch between proliferation (nuclear ERK) and differentiation (cytoplasmic ERK) of muscle progenitors. A myristoylated peptide that blocks importin 7-mediated ERK nuclear translocation induced robust myogenic differentiation of muscle progenitor/stem cells in both head and trunk. In the mouse, analysis of Sprouty mutant embryos revealed that increased ERK signaling suppressed both head and trunk myogenesis. Our findings, corroborated by mathematical modeling, suggest that ERK shuttling between the nucleus and the cytoplasm provides a switch-like transition between proliferation and differentiation of muscle progenitors.
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http://dx.doi.org/10.1242/dev.107078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4067960PMC
July 2014