Publications by authors named "Michael Schotsaert"

47 Publications

Introduction of Two Prolines and Removal of the Polybasic Cleavage Site Lead to Higher Efficacy of a Recombinant Spike-Based SARS-CoV-2 Vaccine in the Mouse Model.

mBio 2021 03 2;12(2). Epub 2021 Mar 2.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the prime target for vaccine development. The spike protein mediates both binding to host cells and membrane fusion and is also so far the only known viral target of neutralizing antibodies. Coronavirus spike proteins are large trimers that are relatively unstable, a feature that might be enhanced by the presence of a polybasic cleavage site in SARS-CoV-2 spike. Exchange of K986 and V987 for prolines has been shown to stabilize the trimers of SARS-CoV-1 and the Middle East respiratory syndrome coronavirus spike proteins. Here, we test multiple versions of a soluble spike protein for their immunogenicity and protective effect against SARS-CoV-2 challenge in a mouse model that transiently expresses human angiotensin-converting enzyme 2 via adenovirus transduction. Variants tested include spike proteins with a deleted polybasic cleavage site, proline mutations, or a combination thereof, besides the wild-type protein. While all versions of the protein were able to induce neutralizing antibodies, only the antigen with both a deleted cleavage site and the K986P and V987P (PP) mutations completely protected from challenge in this mouse model. A vaccine for SARS-CoV-2 is urgently needed. A better understanding of antigen design and attributes that vaccine candidates need to have to induce protective immunity is of high importance. The data presented here validate the choice of antigens that contain the PP mutations and suggest that deletion of the polybasic cleavage site may lead to a further-optimized design.
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http://dx.doi.org/10.1128/mBio.02648-20DOI Listing
March 2021

A Combination Adjuvant for the Induction of Potent Antiviral Immune Responses for a Recombinant SARS-CoV-2 Protein Vaccine.

bioRxiv 2021 Feb 18. Epub 2021 Feb 18.

Several promising vaccines for SARS-CoV-2 have received emergency use authorization in various countries and are being administered to the general population. However, many issues associated with the vaccines and the protection they provide remain unresolved, including the duration of conferred immunity, whether or not sterilizing immunity is imparted, and the degree of cross-variant protection that is achieved with these vaccines. Early evidence has suggested potentially reduced vaccine efficacy towards certain viral variants in circulation. Development of adjuvants compatible with these vaccine platforms that enhance the immune response and guide the adaptive and cellular immune responses towards the types of responses most effective for broad protection against SARS-CoV-2 will likely be pivotal for complete protection. Natural viral infection stimulates strong immune responses through the activation of three main pathways involving Toll-, RIG-I-, and NOD-like receptors (TLRs, RLRs, NLRs). As induction of appropriate innate responses is crucial for long-lasting adaptive immunity and for shaping the correct types of immune responses, we developed a combination, intranasal, adjuvant integrating a nanoemulsion-based adjuvant (NE) that activates TLRs and NLRP3 with an RNA agonist of RIG-I (IVT DI). This rationally designed combination adjuvant yielded a synergistic immune response with highly robust humoral and cellular responses towards SARS-CoV-2 using a recombinant spike protein S1 subunit antigen. Significantly enhanced virus neutralizing antibody titers were achieved towards both a homologous SARS-CoV-2 virus (IC50 titers of 1:10 ) and a mouse-adapted variant containing the N501Y mutation present in the B1.1.7 UK and B.1.351 South Africa variants. Importantly, NE/IVT DI dramatically enhanced the T 1-biased cellular response, which is expected to provide more durable and tailored cellular immunity while avoiding potential vaccine enhanced pathology previously associated with T 2-biased responses in some SARS-CoV and MERS-CoV vaccines. Our previous work with the NE/IVT DI adjuvant has demonstrated its compatibility with a broad range of antigen types. Thus, this combined adjuvant approach has strong potential for improving the induced immune profile for a variety of SARS-CoV-2 vaccine candidates such that better protection against future drift variants and prevention of transmission can be achieved.
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http://dx.doi.org/10.1101/2021.02.18.431484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899444PMC
February 2021

COVA1-18 neutralizing antibody protects against SARS-CoV-2 in three preclinical models.

Res Sq 2021 Feb 15. Epub 2021 Feb 15.

One year into the Coronavirus Disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), effective treatments are still needed . Monoclonal antibodies, given alone or as part of a therapeutic cocktail, have shown promising results in patients, raising the hope that they could play an important role in preventing clinical deterioration in severely ill or in exposed, high risk individuals . Here, we evaluated the prophylactic and therapeutic effect of COVA1-18 , a neutralizing antibody isolated from a convalescent patient and highly potent against the B.1.1.7. isolate . In both prophylactic and therapeutic settings, SARS-CoV-2 remained undetectable in the lungs of COVA1-18 treated hACE2 mice. Therapeutic treatment also caused a dramatic reduction in viral loads in the lungs of Syrian hamsters. When administered at 10 mg kg one day prior to a high dose SARS-CoV-2 challenge in cynomolgus macaques, COVA1-18 had a very strong antiviral activity in the upper respiratory compartments with an estimated reduction in viral infectivity of more than 95%, and prevented lymphopenia and extensive lung lesions. Modelling and experimental findings demonstrate that COVA1-18 has a strong antiviral activity in three different preclinical models and could be a valuable candidate for further clinical evaluation.
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http://dx.doi.org/10.21203/rs.3.rs-235272/v1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899470PMC
February 2021

The E484K mutation in the SARS-CoV-2 spike protein reduces but does not abolish neutralizing activity of human convalescent and post-vaccination sera.

medRxiv 2021 Jan 29. Epub 2021 Jan 29.

One year in the coronavirus disease 2019 (COVID-19) pandemic, the first vaccines are being rolled out under emergency use authorizations. It is of great concern that newly emerging variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can escape antibody-mediated protection induced by previous infection or vaccination through mutations in the spike protein. The glutamate (E) to Lysine (K) substitution at position 484 (E484K) in the receptor binding domain (RBD) of the spike protein is present in the rapidly spreading variants of concern belonging to the B.1.351 and P.1 lineages. We performed in vitro microneutralization assays with both the USA-WA1/2020 virus and a recombinant (r)SARS-CoV-2 virus that is identical to USA-WA1/2020 except for the E484K mutation introduced in the spike RBD. We selected 34 sera from study participants based on their SARS-CoV-2 spike ELISA antibody titer (negative [N=4] versus weak [N=8], moderate [N=11] or strong positive [N=11]). In addition, we included sera from five individuals who received two doses of the Pfizer SARS-CoV-2 vaccine BNT162b2. Serum neutralization efficiency was lower against the E484K rSARS-CoV-2 (vaccination samples: 3.4 fold; convalescent low IgG: 2.4 fold, moderate IgG: 4.2 fold and high IgG: 2.6 fold) compared to USA-WA1/2020. For some of the convalescent donor sera with low or moderate IgG against the SARS-CoV-2 spike, the drop in neutralization efficiency resulted in neutralization ID50 values similar to negative control samples, with low or even absence of neutralization of the E484K rSARS-CoV-2. However, human sera with high neutralization titers against the USA-WA1/2020 strain were still able to neutralize the E484K rSARS-CoV-2. Therefore, it is important to aim for the highest titers possible induced by vaccination to enhance protection against newly emerging SARS-CoV-2 variants. Two vaccine doses may be needed for induction of high antibody titers against SARS-CoV-2. Postponing the second vaccination is suggested by some public health authorities in order to provide more individuals with a primer vaccination. Our data suggests that this may leave vaccinees less protected against newly emerging variants.
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http://dx.doi.org/10.1101/2021.01.26.21250543DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7852247PMC
January 2021

The N501Y mutation in SARS-CoV-2 spike leads to morbidity in obese and aged mice and is neutralized by convalescent and post-vaccination human sera.

medRxiv 2021 Jan 20. Epub 2021 Jan 20.

The current COVID-19 (coronavirus disease 19) pandemic, caused by SARS-CoV-2, disproportionally affects the elderly and people with comorbidities like obesity and associated type 2 diabetes mellitus. Small animal models are crucial for the successful development and validation of antiviral vaccines, therapies and to study the role that comorbidities have on the outcome of viral infections. The initially available SARS-CoV-2 isolates require adaptation in order to use the mouse angiotensin converting enzyme 2 (mACE-2) entry receptor and to productively infect the cells of the murine respiratory tract. We have "mouse-adapted" SARS-CoV-2 by serial passaging a clinical virus isolate in the lungs of mice. We then used low doses of this virus in mouse models for advanced age, diabetes and obesity. Similar to SARS-CoV-2 infection in humans, the outcome of infection with mouse-adapted SARS-CoV-2 resulted in enhanced morbidity in aged and diabetic obese mice. Mutations associated with mouse adaptation occurred in the S, M, N and ORF8 genes. Interestingly, one mutation in the receptor binding domain of the S protein results in the change of an asparagine to tyrosine residue at position 501 (N501Y). This mutation is also present in the newly emerging SARS-CoV-2 variant viruses reported in the U.K. (20B/501Y.V1, B1.1.7 lineage) that is epidemiologically associated with high human to human transmission. We show that human convalescent and post vaccination sera can neutralize the newly emerging N501Y virus variant with similar efficiency as that of the reference USA-WA1/2020 virus, suggesting that current SARS-CoV-2 vaccines will protect against the 20B/501Y.V1 strain.
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http://dx.doi.org/10.1101/2021.01.19.21249592DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7836140PMC
January 2021

Plitidepsin has potent preclinical efficacy against SARS-CoV-2 by targeting the host protein eEF1A.

Science 2021 02 25;371(6532):926-931. Epub 2021 Jan 25.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral proteins interact with the eukaryotic translation machinery, and inhibitors of translation have potent antiviral effects. We found that the drug plitidepsin (aplidin), which has limited clinical approval, possesses antiviral activity (90% inhibitory concentration = 0.88 nM) that is more potent than remdesivir against SARS-CoV-2 in vitro by a factor of 27.5, with limited toxicity in cell culture. Through the use of a drug-resistant mutant, we show that the antiviral activity of plitidepsin against SARS-CoV-2 is mediated through inhibition of the known target eEF1A (eukaryotic translation elongation factor 1A). We demonstrate the in vivo efficacy of plitidepsin treatment in two mouse models of SARS-CoV-2 infection with a reduction of viral replication in the lungs by two orders of magnitude using prophylactic treatment. Our results indicate that plitidepsin is a promising therapeutic candidate for COVID-19.
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http://dx.doi.org/10.1126/science.abf4058DOI Listing
February 2021

Sterilizing Immunity against SARS-CoV-2 Infection in Mice by a Single-Shot and Lipid Amphiphile Imidazoquinoline TLR7/8 Agonist-Adjuvanted Recombinant Spike Protein Vaccine.

Angew Chem Int Ed Engl 2021 Jan 19. Epub 2021 Jan 19.

Mount Sinai School of Medicine: Icahn School of Medicine at Mount Sinai, Microbiology, UNITED STATES.

The search for vaccines that protect from severe morbidity and mortality as a result of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19) is a race against the clock and the virus. Here we describe the use of a novel amphiphilic imidazoquinoline (IMDQ-PEG-CHOL) TLR7/8 adjuvant, consisting of an imidazoquinoline conjugated to the chain end of a cholesterol-poly(ethylene glycol) macromolecular amphiphile. This amphiphile is water soluble and exhibits massive translocation to lymph nodes upon local administration, likely through binding to albumin, affording localized innate immune activation and a dramatic reduction in systemic inflammation. The adjuvanticity of IMDQ-PEG-CHOL was validated in the context of a licensed vaccine setting (i.e. the quadrivalent influenza vaccine) and an experimental trimeric recombinant SARS-CoV-2 spike protein vaccine, showing robust IgG2a and IgG1 antibody titers in mice that could neutralize viral infection in vitro and in vivo in a mouse model.
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http://dx.doi.org/10.1002/anie.202015362DOI Listing
January 2021

Topoisomerase 1 inhibition therapy protects against SARS-CoV-2-induced inflammation and death in animal models.

bioRxiv 2020 Dec 1. Epub 2020 Dec 1.

The ongoing pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is currently affecting millions of lives worldwide. Large retrospective studies indicate that an elevated level of inflammatory cytokines and pro-inflammatory factors are associated with both increased disease severity and mortality. Here, using multidimensional epigenetic, transcriptional, and analyses, we report that Topoisomerase 1 (Top1) inhibition suppresses lethal inflammation induced by SARS-CoV-2. Therapeutic treatment with two doses of Topotecan (TPT), a FDA-approved Top1 inhibitor, suppresses infection-induced inflammation in hamsters. TPT treatment as late as four days post-infection reduces morbidity and rescues mortality in a transgenic mouse model. These results support the potential of Top1 inhibition as an effective host-directed therapy against severe SARS-CoV-2 infection. TPT and its derivatives are inexpensive clinical-grade inhibitors available in most countries. Clinical trials are needed to evaluate the efficacy of repurposing Top1 inhibitors for COVID-19 in humans.
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http://dx.doi.org/10.1101/2020.12.01.404483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7724667PMC
December 2020

Respiratory tissue-associated commensal bacteria offer therapeutic potential against pneumococcal colonization.

Elife 2020 12 8;9. Epub 2020 Dec 8.

Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.

Under eubiotic conditions commensal microbes are known to provide a competitive barrier against invading bacterial pathogens in the intestinal tract, on the skin or on the vaginal mucosa. Here, we evaluate the role of lung microbiota in Pneumococcus colonization of the lungs. In eubiosis, the lungs of mice were dominantly colonized by . Differential analysis of 16S rRNA gene sequencing or specific qPCR of DNA from total organ homogenates broncho alveolar lavages implicated tight association of these bacteria with the host tissue. Pure conditioned culture medium inhibited growth and reduced the extension of pneumococcal chains. Growth inhibition in vitro was likely dependent on -produced lactic acid, since pH neutralization of the conditioned medium aborted the antibacterial effect. Finally, we demonstrate that provides a barrier against pneumococcal colonization in a respiratory dysbiosis model after an influenza A virus infection, when added therapeutically.
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http://dx.doi.org/10.7554/eLife.53581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723408PMC
December 2020

Sterilizing Immunity against SARS-CoV-2 Infection in Mice by a Single-Shot and Modified Imidazoquinoline TLR7/8 Agonist-Adjuvanted Recombinant Spike Protein Vaccine.

bioRxiv 2020 Oct 23. Epub 2020 Oct 23.

Department of Microbiology, Icahn School of Medicine at Mount Sinai New York, NY, USA.

The search for vaccines that protect from severe morbidity and mortality as a result of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19) is a race against the clock and the virus. Several vaccine candidates are currently being tested in the clinic. Inactivated virus and recombinant protein vaccines can be safe options but may require adjuvants to induce robust immune responses efficiently. In this work we describe the use of a novel amphiphilic imidazoquinoline (IMDQ-PEG-CHOL) TLR7/8 adjuvant, consisting of an imidazoquinoline conjugated to the chain end of a cholesterol-poly(ethylene glycol) macromolecular amphiphile). This amphiphile is water soluble and exhibits massive translocation to lymph nodes upon local administration, likely through binding to albumin. IMDQ-PEG-CHOL is used to induce a protective immune response against SARS-CoV-2 after single vaccination with trimeric recombinant SARS-CoV-2 spike protein in the BALB/c mouse model. Inclusion of amphiphilic IMDQ-PEG-CHOL in the SARS-CoV-2 spike vaccine formulation resulted in enhanced immune cell recruitment and activation in the draining lymph node. IMDQ-PEG-CHOL has a better safety profile compared to native soluble IMDQ as the former induces a more localized immune response upon local injection, preventing systemic inflammation. Moreover, IMDQ-PEG-CHOL adjuvanted vaccine induced enhanced ELISA and in vitro microneutralization titers, and a more balanced IgG2a/IgG1 response. To correlate vaccine responses with control of virus replication in vivo, vaccinated mice were challenged with SARS-CoV-2 virus after being sensitized by intranasal adenovirus-mediated expression of the human angiotensin converting enzyme 2 (ACE2) gene. Animals vaccinated with trimeric recombinant spike protein vaccine without adjuvant had lung virus titers comparable to non-vaccinated control mice, whereas animals vaccinated with IMDQ-PEG-CHOL-adjuvanted vaccine controlled viral replication and infectious viruses could not be recovered from their lungs at day 4 post infection. In order to test whether IMDQ-PEG-CHOL could also be used to adjuvant vaccines currently licensed for use in humans, proof of concept was also provided by using the same IMDQ-PEG-CHOL to adjuvant human quadrivalent inactivated influenza virus split vaccine, which resulted in enhanced hemagglutination inhibition titers and a more balanced IgG2a/IgG1 antibody response. Enhanced influenza vaccine responses correlated with better virus control when mice were given a lethal influenza virus challenge. Our results underscore the potential use of IMDQ-PEG-CHOL as an adjuvant to achieve protection after single immunization with recombinant protein and inactivated virus vaccines against respiratory viruses, such as SARS-CoV-2 and influenza viruses.
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http://dx.doi.org/10.1101/2020.10.23.344085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7587831PMC
October 2020

SARS-CoV-2 Orf6 hijacks Nup98 to block STAT nuclear import and antagonize interferon signaling.

Proc Natl Acad Sci U S A 2020 11 23;117(45):28344-28354. Epub 2020 Oct 23.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029;

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic that is a serious global health problem. Evasion of IFN-mediated antiviral signaling is a common defense strategy that pathogenic viruses use to replicate and propagate in their host. In this study, we show that SARS-CoV-2 is able to efficiently block STAT1 and STAT2 nuclear translocation in order to impair transcriptional induction of IFN-stimulated genes (ISGs). Our results demonstrate that the viral accessory protein Orf6 exerts this anti-IFN activity. We found that SARS-CoV-2 Orf6 localizes at the nuclear pore complex (NPC) and directly interacts with Nup98-Rae1 via its C-terminal domain to impair docking of cargo-receptor (karyopherin/importin) complex and disrupt nuclear import. In addition, we show that a methionine-to-arginine substitution at residue 58 impairs Orf6 binding to the Nup98-Rae1 complex and abolishes its IFN antagonistic function. All together our data unravel a mechanism of viral antagonism in which a virus hijacks the Nup98-Rae1 complex to overcome the antiviral action of IFN.
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http://dx.doi.org/10.1073/pnas.2016650117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7668094PMC
November 2020

Comparison of transgenic and adenovirus hACE2 mouse models for SARS-CoV-2 infection.

Emerg Microbes Infect 2020 Dec;9(1):2433-2445

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is currently causing a worldwide pandemic with high morbidity and mortality. Development of animal models that recapitulate important aspects of coronavirus disease 2019 (COVID-19) is critical for the evaluation of vaccines and antivirals, and understanding disease pathogenesis. SARS-CoV-2 has been shown to use the same entry receptor as SARS-CoV-1, human angiotensin-converting enzyme 2 (hACE2) [1-3]. Due to amino acid differences between murine and hACE2, inbred mouse strains fail to support high titer viral replication of SARS-CoV-2 virus. Therefore, a number of transgenic and knock-in mouse models, as well as viral vector-mediated hACE2 delivery systems have been developed. Here we compared the K18-hACE2 transgenic model to adenovirus-mediated delivery of hACE2 to the mouse lung. We show that K18-hACE2 mice replicate virus to high titers in the nasal turbinates, lung and brain, with high lethality, and cytokine/chemokine production. In contrast, adenovirus-mediated delivery results in viral replication to lower titers limited to the nasal turbinates and lung, and no clinical signs of infection. The K18-hACE2 model provides a stringent model for testing vaccines and antivirals, whereas the adenovirus delivery system has the flexibility to be used across multiple genetic backgrounds and modified mouse strains.
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http://dx.doi.org/10.1080/22221751.2020.1838955DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655046PMC
December 2020

Scalable, effective, and rapid decontamination of SARS-CoV-2 contaminated N95 respirators using germicidal ultra-violet C (UVC) irradiation device.

medRxiv 2020 Oct 6. Epub 2020 Oct 6.

Importance: Particulate respirators such as N95 masks are an essential component of personal protective equipment (PPE) for front-line workers. This study describes a rapid and effective UVC irradiation system that would facilitate the safe re-use of N95 respirators and provides supporting information for deploying UVC for decontamination of SARS-CoV-2 during the COVID19 pandemic.

Objective: To assess the inactivation potential of the proposed UVC germicidal device as a function of time by using 3M 8211 - N95 particulate respirators inoculated with SARS-CoV-2.

Design: A germicidal UVC device to deliver tailored UVC dose was developed and snippets (2.5cm2) of the 3M-N95 respirator were inoculated with 106 plaque-forming units (PFU) of SARS-CoV-2 and were UV irradiated. Different exposure times were tested (0-164 seconds) by fixing the distance between the lamp (10 cm) and the mask while providing an exposure of at least 5.43 mWcm-2.

Setting: The current work is broadly applicable for healthcare-settings, particularly during a pandemic such as COVID-19.

Participants: Not applicable. Main Outcome(s) and Measure(s): Primary measure of outcome was titration of infectious virus recovered from virus-inoculated respirator pieces after UVC exposure. Other measures included the method validation of the irradiation protocol, using lentiviruses (biosafety level-2 agent) and establishment of the germicidal UVC exposure protocol.

Results: An average of 4.38x103 PFUml-1(SD 772.68) was recovered from untreated masks while 4.44x102 PFUml-1(SD 203.67), 4.00x102 PFUml-1(SD 115.47), 1.56x102 PFUml-1(SD 76.98) and 4.44x101 PFUml-1(SD 76.98) was recovered in exposures 2s,6s,18s and 54 seconds per side respectively. The germicidal device output and positioning was monitored and a minimum output of 5.43 mWcm-2 was maintained. Infectious SARS-CoV-2 was not detected by plaque assays (minimal level of detection is 67 PFUml-1) on N95 respirator snippets when irradiated for 120s per side or longer suggesting 3.5 log reduction in 240 seconds of irradiation.

Conclusions And Relevance: A scalable germicidal UVC device to deliver tailored UVC dose for rapid decontamination of SARS-CoV-2 was developed. UVC germicidal irradiation of N95 snippets inoculated with SARS-CoV-2 for 120s per side resulted in 100% (3.5 log in total) reduction of virus. These data support the reuse of N95 particle-filtrate apparatus upon irradiation with UVC and supports use of UVC-based decontamination of SARS-CoV-2 virus during the COVID19 pandemic.
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http://dx.doi.org/10.1101/2020.10.05.20206953DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7553180PMC
October 2020

Introduction of two prolines and removal of the polybasic cleavage site leads to optimal efficacy of a recombinant spike based SARS-CoV-2 vaccine in the mouse model.

bioRxiv 2020 Sep 17. Epub 2020 Sep 17.

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the prime target for vaccine development. The spike protein mediates both binding to host cells and membrane fusion and is also so far the only known viral target of neutralizing antibodies. Coronavirus spike proteins are large trimers that are relatively instable, a feature that might be enhanced by the presence of a polybasic cleavage site in the SARS-CoV-2 spike. Exchange of K986 and V987 to prolines has been shown to stabilize the trimers of SARS-CoV-1 and the Middle Eastern respiratory syndrome coronavirus spikes. Here, we test multiple versions of a soluble spike protein for their immunogenicity and protective effect against SARS-CoV-2 challenge in a mouse model that transiently expresses human angiotensin converting enzyme 2 via adenovirus transduction. Variants tested include spike protein with a deleted polybasic cleavage site, the proline mutations, a combination thereof, as well as the wild type protein. While all versions of the protein were able to induce neutralizing antibodies, only the antigen with both a deleted cleavage site and the PP mutations completely protected from challenge in this mouse model.

Importance: A vaccine for SARS-CoV-2 is urgently needed. A better understanding of antigen design and attributes that vaccine candidates need to have to induce protective immunity is of high importance. The data presented here validates the choice of antigens that contain the PP mutation and suggests that deletion of the polybasic cleavage site could lead to a further optimized design.
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http://dx.doi.org/10.1101/2020.09.16.300970DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523111PMC
September 2020

Animal models for COVID-19.

Nature 2020 10 23;586(7830):509-515. Epub 2020 Sep 23.

Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the aetiological agent of coronavirus disease 2019 (COVID-19), an emerging respiratory infection caused by the introduction of a novel coronavirus into humans late in 2019 (first detected in Hubei province, China). As of 18 September 2020, SARS-CoV-2 has spread to 215 countries, has infected more than 30 million people and has caused more than 950,000 deaths. As humans do not have pre-existing immunity to SARS-CoV-2, there is an urgent need to develop therapeutic agents and vaccines to mitigate the current pandemic and to prevent the re-emergence of COVID-19. In February 2020, the World Health Organization (WHO) assembled an international panel to develop animal models for COVID-19 to accelerate the testing of vaccines and therapeutic agents. Here we summarize the findings to date and provides relevant information for preclinical testing of vaccine candidates and therapeutic agents for COVID-19.
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http://dx.doi.org/10.1038/s41586-020-2787-6DOI Listing
October 2020

Discovery of SARS-CoV-2 antiviral drugs through large-scale compound repurposing.

Nature 2020 10 24;586(7827):113-119. Epub 2020 Jul 24.

Immunity and Pathogenesis Program, Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 has triggered an ongoing global pandemic of the severe pneumonia-like disease coronavirus disease 2019 (COVID-19). The development of a vaccine is likely to take at least 12-18 months, and the typical timeline for approval of a new antiviral therapeutic agent can exceed 10 years. Thus, repurposing of known drugs could substantially accelerate the deployment of new therapies for COVID-19. Here we profiled a library of drugs encompassing approximately 12,000 clinical-stage or Food and Drug Administration (FDA)-approved small molecules to identify candidate therapeutic drugs for COVID-19. We report the identification of 100 molecules that inhibit viral replication of SARS-CoV-2, including 21 drugs that exhibit dose-response relationships. Of these, thirteen were found to harbour effective concentrations commensurate with probable achievable therapeutic doses in patients, including the PIKfyve kinase inhibitor apilimod and the cysteine protease inhibitors MDL-28170, Z LVG CHN2, VBY-825 and ONO 5334. Notably, MDL-28170, ONO 5334 and apilimod were found to antagonize viral replication in human pneumocyte-like cells derived from induced pluripotent stem cells, and apilimod also demonstrated antiviral efficacy in a primary human lung explant model. Since most of the molecules identified in this study have already advanced into the clinic, their known pharmacological and human safety profiles will enable accelerated preclinical and clinical evaluation of these drugs for the treatment of COVID-19.
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http://dx.doi.org/10.1038/s41586-020-2577-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7603405PMC
October 2020

Comparison of Transgenic and Adenovirus hACE2 Mouse Models for SARS-CoV-2 Infection.

bioRxiv 2020 Jul 6. Epub 2020 Jul 6.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.

Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is currently causing a worldwide pandemic with high morbidity and mortality. Development of animal models that recapitulate important aspects of coronavirus disease 2019 (COVID-19) is critical for the evaluation of vaccines and antivirals, and understanding disease pathogenesis. SARS-CoV-2 has been shown to use the same entry receptor as SARS-CoV-1, human angiotensin-converting enzyme 2 (hACE2)(1-3). Due to amino acid differences between murine and hACE2, inbred mouse strains fail to support high titer viral replication of SARS-CoV-2 virus. Therefore, a number of transgenic and knock-in mouse models, as well as viral vector-mediated hACE2 delivery systems have been developed. Here we compared the K18-hACE2 transgenic model to adenovirus-mediated delivery of hACE2 to the mouse lung. We show that K18-hACE2 mice replicate virus to high titers in both the lung and brain leading to lethality. In contrast, adenovirus-mediated delivery results in viral replication to lower titers limited to the lung, and no clinical signs of infection with a challenge dose of 10 plaque forming units. The K18-hACE2 model provides a stringent model for testing the ability of vaccines and antivirals to protect against disease, whereas the adenovirus delivery system has the flexibility to be used across multiple genetic backgrounds and modified mouse strains.
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http://dx.doi.org/10.1101/2020.07.06.190066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359525PMC
July 2020

Current Status of COVID-19 (Pre)Clinical Vaccine Development.

Angew Chem Int Ed Engl 2020 10 2;59(43):18885-18897. Epub 2020 Sep 2.

Department of Pharmaceutics, Ghent University, Belgium.

The current COVID-19 pandemic has a tremendous impact on daily life world-wide. Despite the ability to dampen the spread of SARS-CoV-2, the causative agent of the diseases, through restrictive interventions, it is believed that only effective vaccines will provide sufficient control over the disease and revert societal live back to normal. At present, a double-digit number of efforts are devoted to the development of a vaccine against COVID-19. Here, we provide an overview of these (pre)clinical efforts and provide background information on the technologies behind these vaccines. In addition, we discuss potential hurdles that need to be addressed prior to mass scale clinical translation of successful vaccine candidates.
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http://dx.doi.org/10.1002/anie.202008319DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7405471PMC
October 2020

Non-sterilizing, Infection-Permissive Vaccination With Inactivated Influenza Virus Vaccine Reshapes Subsequent Virus Infection-Induced Protective Heterosubtypic Immunity From Cellular to Humoral Cross-Reactive Immune Responses.

Front Immunol 2020 9;11:1166. Epub 2020 Jun 9.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.

Conventional influenza vaccines aim at the induction of virus-neutralizing antibodies that provide with sterilizing immunity. However, influenza vaccination often confers protection from disease but not from infection. The impact of infection-permissive vaccination on the immune response elicited by subsequent influenza virus infection is not well-understood. Here, we investigated to what extent infection-permissive immunity, in contrast to virus-neutralizing immunity, provided by a trivalent inactivated virus vaccine (TIV) modulates disease and virus-induced host immune responses after sublethal vaccine-matching H1N1 infection in a mouse model. More than one TIV vaccination was needed to induce a serum HI titer and provide sterilizing immunity upon homologous virus infection. However, single TIV administration provided infection-permissive immunity, characterized by lower viral lung titers and faster recovery. Despite the presence of replicating virus, single TIV vaccination prevented induction of pro-inflammatory cyto- and chemokines, alveolar macrophage depletion as well as the establishment of lung-resident B and T cells after infection. To investigate virus infection-induced cross-protective heterosubtypic immune responses in vaccinated and unvaccinated animals, mice were re-infected with a lethal dose of H3N2 virus 4 weeks after H1N1 infection. Single TIV vaccination did not prevent H1N1 virus infection-induced heterosubtypic cross-protection, but shifted the mechanism of cross-protection from the cellular to the humoral branch of the immune system. These results suggest that suboptimal vaccination with conventional influenza vaccines may still positively modulate disease outcome after influenza virus infection, while promoting humoral heterosubtypic immunity after virus infection.
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http://dx.doi.org/10.3389/fimmu.2020.01166DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296151PMC
June 2020

A cross-reactive mouse monoclonal antibody against rhinovirus mediates phagocytosis in vitro.

Sci Rep 2020 06 16;10(1):9750. Epub 2020 Jun 16.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Rhinoviruses (RVs) are the main cause of the common cold worldwide. To date, more than 160 types of the virus have been recognized, categorized into three major species - A, B, and C. There are currently no approved vaccines available to prevent infection with RVs. To elicit antibodies against conserved regions located on capsid proteins of RV A viruses, mice were sequentially vaccinated with DNA plasmids encoding capsid proteins of different RV A types. After a final boost with whole virus, antibody-expressing hybridomas were generated. After isotyping, 11 monoclonal antibodies (mAbs) expressing an IgG subtype Fc-domain were selected for further expansion and purification. Three mAbs showed cross-reactivity against multiple strains of RV A viruses by ELISA, including strains A1A, A1B, A15, A16 and A49. Other mAbs had strain-specific binding patterns, with the majority of mAbs showing reactivity to RV-A15, the strain used for the final vaccination. We found that the RV-A15-specific mAbs, but not the cross-reactive mAbs, had neutralizing activity against RV-A15. An antibody dependent cellular phagocytosis (ADCP) assay revealed substantial ADCP activity for one of the cross-reactive mAbs. Epitope mapping of the neutralizing mAbs via escape mutant virus generation revealed a shared binding epitope on VP1 of RV-A15 for several neutralizing mAbs. The epitope of the ADCP-active, non-neutralizing mAb was determined by microarray analysis of peptides generated from the VP1 capsid protein. VP1-specific, cross-reactive antibodies, especially those with ADCP activity, could contribute to protection against RV infections.
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http://dx.doi.org/10.1038/s41598-020-66600-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297972PMC
June 2020

Host immune response-inspired development of the influenza vaccine.

Ann Allergy Asthma Immunol 2020 07 20;125(1):28-35. Epub 2020 Apr 20.

Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York. Electronic address:

Objective: To assess the current and future development of influenza vaccines.

Data Sources: PubMed searches were performed cross-referencing the keywords influenza, influenza vaccine, host immune response, correlates of protection, vaccine development, vaccine efficacy. Articles were reviewed for additional citations.

Study Selections: Articles were reviewed and selected on the basis of relevance to subject matter.

Results: In this review, we first introduce the influenza virus, its nomenclature, and the concepts of antigenic drift and shift. Second, we discuss the status of currently licensed influenza virus vaccines. We briefly focus on influenza vaccine responses beyond hemagglutination inhibition that may correlate with protection against influenza viruses of different subtypes. Third, we explain how studying host responses to influenza infection and vaccination with advanced serologic methods, B-cell receptor sequencing, and transcriptomic profiling can guide the development of improved influenza virus vaccines. Fourth, we provide 2 suggestions on how current influenza vaccines can be optimized by redirecting immune responses toward conserved viral antigens and the use of adjuvants.

Conclusion: Influenza vaccine design can benefit from novel insights obtained from the study of host responses to influenza virus infection and vaccination. Integration of the large amount of available clinical and preclinical data requires systems approaches that can elucidate novel correlates of protection and will guide further development of influenza vaccine.
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http://dx.doi.org/10.1016/j.anai.2020.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327511PMC
July 2020

TIV Vaccination Modulates Host Responses to Influenza Virus Infection that Correlate with Protection against Bacterial Superinfection.

Vaccines (Basel) 2019 Sep 12;7(3). Epub 2019 Sep 12.

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.

Background: Influenza virus infection predisposes to secondary bacterial pneumonia. Currently licensed influenza vaccines aim at the induction of neutralizing antibodies and are less effective if the induction of neutralizing antibodies is low and/or the influenza virus changes its antigenic surface. We investigated the effect of suboptimal vaccination on the outcome of post-influenza bacterial superinfection.

Methods: We established a mouse vaccination model that allows control of disease severity after influenza virus infection despite inefficient induction of virus-neutralizing antibody titers by vaccination. We investigated the effect of vaccination on virus-induced host immune responses and on the outcome of superinfection with .

Results: Vaccination with trivalent inactivated virus vaccine (TIV) reduced morbidity after influenza A virus infection but did not prevent virus replication completely. Despite the poor induction of influenza-specific antibodies, TIV protected from mortality after bacterial superinfection. Vaccination limited loss of alveolar macrophages and reduced levels of infiltrating pulmonary monocytes after influenza virus infection. Interestingly, TIV vaccination resulted in enhanced levels of eosinophils after influenza virus infection and recruitment of neutrophils in both lungs and mediastinal lymph nodes after bacterial superinfection.

Conclusion: These observations highlight the importance of disease modulation by influenza vaccination, even when suboptimal, and suggest that influenza vaccination is still beneficial to protect during bacterial superinfection in the absence of complete virus neutralization.
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http://dx.doi.org/10.3390/vaccines7030113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6789870PMC
September 2019

A Site of Vulnerability on the Influenza Virus Hemagglutinin Head Domain Trimer Interface.

Cell 2019 05;177(5):1136-1152.e18

Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA. Electronic address:

Here, we describe the discovery of a naturally occurring human antibody (Ab), FluA-20, that recognizes a new site of vulnerability on the hemagglutinin (HA) head domain and reacts with most influenza A viruses. Structural characterization of FluA-20 with H1 and H3 head domains revealed a novel epitope in the HA trimer interface, suggesting previously unrecognized dynamic features of the trimeric HA protein. The critical HA residues recognized by FluA-20 remain conserved across most subtypes of influenza A viruses, which explains the Ab's extraordinary breadth. The Ab rapidly disrupted the integrity of HA protein trimers, inhibited cell-to-cell spread of virus in culture, and protected mice against challenge with viruses of H1N1, H3N2, H5N1, or H7N9 subtypes when used as prophylaxis or therapy. The FluA-20 Ab has uncovered an exceedingly conserved protective determinant in the influenza HA head domain trimer interface that is an unexpected new target for anti-influenza therapeutics and vaccines.
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http://dx.doi.org/10.1016/j.cell.2019.04.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6629437PMC
May 2019

Chimeric Hemagglutinin-Based Influenza Virus Vaccines Induce Protective Stalk-Specific Humoral Immunity and Cellular Responses in Mice.

Immunohorizons 2019 04;3(4):133-148

Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029;

The high variation of the influenza virus hemagglutinin (HA), particularly of its immunodominant head epitopes, makes it necessary to reformulate seasonal influenza virus vaccines every year. Novel influenza virus vaccines that redirect the immune response toward conserved epitopes of the HA stalk domain should afford broad and durable protection. Sequential immunization with chimeric HAs (cHAs) that express the same conserved HA stalk and distinct exotic HA heads has been shown to elicit high levels of broadly cross-reactive Abs. In the current mouse immunization studies, we tested this strategy using inactivated split virion cHA influenza virus vaccines (IIV) without adjuvant or adjuvanted with AS01 or AS03 to measure the impact of adjuvant on the Ab response. The vaccines elicited high levels of cross-reactive Abs that showed activity in an Ab-dependent, cell-mediated cytotoxicity reporter assay and were protective in a mouse viral challenge model after serum transfer. In addition, T cell responses to adjuvanted IIV were compared with responses to a cHA-expressing live attenuated influenza virus vaccine (LAIV). A strong but transient induction of Ag-specific T cells was observed in the spleens of mice vaccinated with LAIV. Interestingly, IIV also induced T cells, which were successfully recalled upon viral challenge. Groups that received AS01-adjuvanted IIV or LAIV 4 wk before the challenge showed the lowest level of viral replication (i.e., the highest level of protection). These studies provide evidence that broadly cross-reactive Abs elicited by cHA vaccination demonstrate Fc-mediated activity. In addition, cHA vaccination induced Ag-specific cellular responses that can contribute to protection upon infection.
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http://dx.doi.org/10.4049/immunohorizons.1900022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485968PMC
April 2019

Erratum: Sunwoo, S.-Y. et al. A Universal Influenza Virus Vaccine Candidate Tested in a Pig Vaccination-Infection Model in the Presence of Maternal Antibodies. Vaccines 2018, 6(3), 64.

Vaccines (Basel) 2018 11 27;6(4). Epub 2018 Nov 27.

Department of Diagnostic Medicine & Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.

In the published article, "A Universal Influenza Virus Vaccine Candidate Tested in a Pig Vaccination-Infection Model in the Presence of Maternal Antibodies. [...].
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http://dx.doi.org/10.3390/vaccines6040080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6313909PMC
November 2018

FACS-Mediated Isolation of Neuronal Cell Populations From Virus-Infected Human Embryonic Stem Cell-Derived Cerebral Organoid Cultures.

Curr Protoc Stem Cell Biol 2019 02 24;48(1):e65. Epub 2018 Oct 24.

Huffington Center for Cell-Based Research, Black Family Stem Cell Institute, Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY.

Organoids-or pluripotent stem cell-derived in vitro-grown simplified mini organs-have become a tremendously important model to study human organ development and disease. To restrict the noise inherent to the heterogeneous cell mixtures derived from organoid cultures, we developed a new technique of fluorescence-assisted cell sorting (FACS) of virus-infected cerebral organoid cultures. This method still includes the advantage of growing cells in a more natural environment than traditional cell culture, but now renders samples suitable for downstream cell type-specific multi-omics analyses. The protocol starts from stem cell-derived mature brain organoids and includes steps for: preparing the culture for viral infection, production of the viral stocks, FACS sample preparation, and gating and sorting implementation. The protocol has been developed for Zika virus infection, but can be extrapolated to other viruses or fluorescent marker expression as illustrated in an alternate protocol using a single-cycle lentivirus expressing a fluorescent reporter protein. © 2018 by John Wiley & Sons, Inc.
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http://dx.doi.org/10.1002/cpsc.65DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6336506PMC
February 2019

A Universal Influenza Virus Vaccine Candidate Tested in a Pig Vaccination-Infection Model in the Presence of Maternal Antibodies.

Vaccines (Basel) 2018 Sep 14;6(3). Epub 2018 Sep 14.

Department of Diagnostic Medicine & Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.

The antigenically conserved hemagglutinin stalk region is a target for universal influenza virus vaccines since antibodies against it can provide broad protection against influenza viruses of different subtypes. We tested a universal influenza virus vaccination regimen based on sequential immunization with chimeric hemagglutinin (HA) containing viruses in a swine influenza virus pig model with maternal antibodies against pandemic H1N1. Vaccines were administered as live attenuated virus or inactivated influenza virus split vaccine (+/- Emulsigen adjuvant). As controls, we included groups that received trivalent inactivated influenza vaccine that contained pandemic H1N1 antigens, inactivated adjuvanted H1N2 vaccine (control group for vaccine associated enhanced respiratory disease in the pig model) or mock-vaccination. No induction of H1 head or stalk-specific antibody responses was observed upon vaccination, while responses against H3 and influenza B HA were elicited in the group vaccinated with the trivalent vaccine. Four weeks post vaccination, pigs were intratracheally challenged with pandemic H1N1 virus and euthanized 5 days after challenge. Despite the lack of detectable anti-stalk immunity, the chimeric hemagglutinin vaccine resulted in better clinical outcomes compared to control groups.
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http://dx.doi.org/10.3390/vaccines6030064DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6161263PMC
September 2018

Spatial-Temporal Lineage Restrictions of Embryonic p63 Progenitors Establish Distinct Stem Cell Pools in Adult Airways.

Dev Cell 2018 03;44(6):752-761.e4

Columbia Center for Human Development, Department of Medicine, Pulmonary Allergy Critical Care, Columbia University Medical Center, New York, NY 10032, USA; Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA. Electronic address:

Basal cells (BCs) are p63-expressing multipotent progenitors of skin, tracheoesophageal and urinary tracts. p63 is abundant in developing airways; however, it remains largely unclear how embryonic p63 cells contribute to the developing and postnatal respiratory tract epithelium, and ultimately how they relate to adult BCs. Using lineage-tracing and functional approaches in vivo, we show that p63 cells arising from the lung primordium are initially multipotent progenitors of airway and alveolar lineages but later become restricted proximally to generate the tracheal adult stem cell pool. In intrapulmonary airways, these cells are maintained immature to adulthood in bronchi, establishing a rare p63Krt5 progenitor cell population that responds to H1N1 virus-induced severe injury. Intriguingly, this pool includes a CC10 lineage-labeled p63Krt5 cell subpopulation required for a full H1N1-response. These data elucidate key aspects in the establishment of regionally distinct adult stem cell pools in the respiratory system, potentially with relevance to other organs.
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http://dx.doi.org/10.1016/j.devcel.2018.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5875454PMC
March 2018

Zika Virus Alters DNA Methylation of Neural Genes in an Organoid Model of the Developing Human Brain.

mSystems 2018 Jan-Feb;3(1). Epub 2018 Feb 6.

Huffington Center for Cell-Based Research in Parkinson's Disease, Black Family Stem Cell Institute, Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

Zika virus (ZIKV) infection during early pregnancy can cause microcephaly and associated defects at birth, but whether it can induce neurologic sequelae that appear later in life remains unclear. Using a model of the developing brain based on embryonic stem cell-derived brain organoids, we studied the impact of ZIKV infection on the DNA methylation pattern across the entire genome in selected neural cell types. The virus unexpectedly alters the DNA methylome of neural progenitors, astrocytes, and differentiated neurons at genes that have been implicated in the pathogenesis of a number of brain disorders, most prominently mental retardation and schizophrenia. Our results suggest that ZIKV infection during fetal development could lead to a spectrum of delayed-onset neuropsychiatric complications. Scientific research on human neural stem cells and cerebral organoids has confirmed the congenital neurotropic and neurodestructive nature of the Zika virus. However, the extent to which prenatal ZIKV infection is associated with more subtle brain alterations, such as epigenetic changes, remains ill defined. Here, we address the question of whether ZIKV infection induces DNA methylation changes with the potential to cause brain disorders later in life.
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http://dx.doi.org/10.1128/mSystems.00219-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801341PMC
February 2018

Pandemic H1N1 influenza A viruses suppress immunogenic RIPK3-driven dendritic cell death.

Nat Commun 2017 12 5;8(1):1931. Epub 2017 Dec 5.

Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.

The risk of emerging pandemic influenza A viruses (IAVs) that approach the devastating 1918 strain motivates finding strain-specific host-pathogen mechanisms. During infection, dendritic cells (DC) mature into antigen-presenting cells that activate T cells, linking innate to adaptive immunity. DC infection with seasonal IAVs, but not with the 1918 and 2009 pandemic strains, induces global RNA degradation. Here, we show that DC infection with seasonal IAV causes immunogenic RIPK3-mediated cell death. Pandemic IAV suppresses this immunogenic DC cell death. Only DC infected with seasonal IAV, but not with pandemic IAV, enhance maturation of uninfected DC and T cell proliferation. In vivo, circulating T cell levels are reduced after pandemic, but not seasonal, IAV infection. Using recombinant viruses, we identify the HA genomic segment as the mediator of cell death inhibition. These results show how pandemic influenza viruses subvert the immune response.
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http://dx.doi.org/10.1038/s41467-017-02035-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5715119PMC
December 2017