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1.
Brief Bioinform ; 2023 May 12.
Article in English | MEDLINE | ID: covidwho-2316531

ABSTRACT

Haplotype networks are graphs used to represent evolutionary relationships between a set of taxa and are characterized by intuitiveness in analyzing genealogical relationships of closely related genomes. We here propose a novel algorithm termed McAN that considers mutation spectrum history (mutations in ancestry haplotype should be contained in descendant haplotype), node size (corresponding to sample count for a given node) and sampling time when constructing haplotype network. We show that McAN is two orders of magnitude faster than state-of-the-art algorithms without losing accuracy, making it suitable for analysis of a large number of sequences. Based on our algorithm, we developed an online web server and offline tool for haplotype network construction, community lineage determination, and interactive network visualization. We demonstrate that McAN is highly suitable for analyzing and visualizing massive genomic data and is helpful to enhance the understanding of genome evolution. Availability: Source code is written in C/C++ and available at https://github.com/Theory-Lun/McAN and https://ngdc.cncb.ac.cn/biocode/tools/BT007301 under the MIT license. Web server is available at https://ngdc.cncb.ac.cn/bit/hapnet/. SARS-CoV-2 dataset are available at https://ngdc.cncb.ac.cn/ncov/. Contact: songshh@big.ac.cn (Song S), zhaowm@big.ac.cn (Zhao W), baoym@big.ac.cn (Bao Y), zhangzhang@big.ac.cn (Zhang Z), ybxue@big.ac.cn (Xue Y).

2.
Biol Direct ; 18(1): 12, 2023 03 28.
Article in English | MEDLINE | ID: covidwho-2289046

ABSTRACT

Viruses rely on hosts for life and reproduction, cause a variety of symptoms from common cold to AIDS to COVID-19 and provoke public health threats claiming millions of lives around the globe. RNA editing, as a crucial co-/post-transcriptional modification inducing nucleotide alterations on both endogenous and exogenous RNA sequences, exerts significant influences on virus replication, protein synthesis, infectivity and toxicity. Hitherto, a number of host-mediated RNA editing sites have been identified in diverse viruses, yet lacking a full picture of RNA editing-associated mechanisms and effects in different classes of viruses. Here we synthesize the current knowledge of host-mediated RNA editing in a variety of viruses by considering two enzyme families, viz., ADARs and APOBECs, thereby presenting a landscape of diverse editing mechanisms and effects between viruses and hosts. In the ongoing pandemic, our study promises to provide potentially valuable insights for better understanding host-mediated RNA editing on ever-reported and newly-emerging viruses.


Subject(s)
COVID-19 , Viruses , Humans , RNA Editing , Viruses/genetics
3.
biorxiv; 2023.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2023.04.19.537460

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved many high-risk variants, resulting in repeated COVID-19 waves of pandemic during the past years. Therefore, accurate early-warning of high-risk variants is vital for epidemic prevention and control. Here we construct a machine learning model to predict high-risk variants of SARS-CoV-2 by LightGBM algorithm based on several important haplotype network features. As demonstrated on a series of different retrospective testing datasets, our model achieves accurate prediction of all variants of concern (VOC) and most variants of interest (AUC=0.96). Prediction based on the latest sequences shows that the newly emerging lineage BA.5 has the highest risk score and spreads rapidly to become a major epidemic lineage in multiple countries, suggesting that BA.5 bears great potential to be a VOC. In sum, our machine learning model is capable to early predict high-risk variants soon after their emergence, thus greatly improving public health preparedness against the evolving virus.


Subject(s)
Coronavirus Infections , COVID-19
4.
JMIR Public Health Surveill ; 8(12): e40771, 2022 12 23.
Article in English | MEDLINE | ID: covidwho-2198136

ABSTRACT

BACKGROUND: The shortage of medical resources in rural China reflects the health inequity in resource-limited settings, whereas telemedicine could provide opportunities to fill this gap. However, evidence of patient acceptance of telemedicine services from low- and middle-income countries is still lacking. OBJECTIVE: We aimed to understand the profile of patient end-user telemedicine use and identify factors influencing telemedicine service use in rural China. METHODS: Our study followed a mixed methods approach, with a quantitative cross-sectional survey followed by in-depth semistructured interviews to describe telemedicine use and its associated factors among rural residents in Guangdong Province, China. In the quantitative analysis, explanatory variables included environmental and context factors, household-level factors, individual sociodemographic factors, access to digital health care, and health needs and demand factors. We conducted univariate and multivariate analyses using Firth logistic regression to examine the correlations of telemedicine uptake. A thematic approach was used, guided by the Social Cognitive Theory for the qualitative analysis. RESULTS: A total of 2101 households were recruited for the quantitative survey. With a mean age of 61.4 (SD 14.41) years, >70% (1364/2101, 72.94%) of the household respondents were male. Less than 1% (14/2101, 0.67%) of the respondents reported experience of using telemedicine. The quantitative results supported that villagers living with family members who had a fever in the past 2 weeks (adjusted odds ratio 6.96, 95% CI 2.20-21.98; P=.001) or having smartphones or computers (adjusted odds ratio 3.71, 95% CI 0.64-21.32; P=.14) had marginally higher telemedicine uptake, whereas the qualitative results endorse these findings. The results of qualitative interviews (n=27) also supplemented the potential barriers to telemedicine use from the lack of knowledge, trust, demand, low self-efficacy, and sufficient physical and social support. CONCLUSIONS: This study found extremely low use of telemedicine in rural China and identified potential factors affecting telemedicine uptake. The main barriers to telemedicine adoption among rural residents were found, including lack of knowledge, trust, demand as well as low self-efficacy, and insufficient physical and social support. Our study also suggests strategies to facilitate telemedicine engagement in low-resource settings: improving digital literacy and self-efficacy, building trust, and strengthening telemedicine infrastructure support.


Subject(s)
Telemedicine , Humans , Male , Middle Aged , Female , Cross-Sectional Studies , Telemedicine/methods , Delivery of Health Care , Smartphone , China
6.
Signal Transduct Target Ther ; 7(1): 318, 2022 09 14.
Article in English | MEDLINE | ID: covidwho-2028663

ABSTRACT

Excessive inflammatory responses contribute to the pathogenesis and lethality of highly pathogenic human coronaviruses, but the underlying mechanism remains unclear. In this study, the N proteins of highly pathogenic human coronaviruses, including severe acute respiratory syndrome coronavirus (SARS-CoV), middle east respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were found to bind MASP-2, a key serine protease in the lectin pathway of complement activation, resulting in excessive complement activation by potentiating MBL-dependent MASP-2 activation, and the deposition of MASP-2, C4b, activated C3 and C5b-9. Aggravated inflammatory lung injury was observed in mice infected with adenovirus expressing the N protein. Complement hyperactivation was also observed in SARS-CoV-2-infected patients. Either blocking the N protein:MASP-2 interaction, MASP-2 depletion or suppressing complement activation can significantly alleviate N protein-induced complement hyperactivation and lung injury in vitro and in vivo. Altogether, these data suggested that complement suppression may represent a novel therapeutic approach for pneumonia induced by these highly pathogenic coronaviruses.


Subject(s)
COVID-19 , Lung Injury , Animals , COVID-19/genetics , Complement Pathway, Mannose-Binding Lectin/genetics , Coronavirus Nucleocapsid Proteins , Humans , Inflammation/genetics , Mannose-Binding Protein-Associated Serine Proteases/genetics , Mannose-Binding Protein-Associated Serine Proteases/metabolism , Mice , SARS-CoV-2
7.
Mathematical Problems in Engineering ; : 1-14, 2022.
Article in English | Academic Search Complete | ID: covidwho-1950448

ABSTRACT

In this article, a cost-benefit decision framework is proposed to analyze the three alternative options of the container fleet capacity renewal for a ship operator. In this decision framework, the ship operator can trade off the following factors: MGO fuel or LNG option vessels, carbon neutrality, and other investment factors. The following variables are considered: the distance of the round trip, the prices of LNG and MGO, the freight rates of each option, and the initial investment ratios of new vessels. It was found that (1) the retrofitted vessels were more stable and suitable in an uncertain shipping market and have better investment potential. (2) The MGO option was the best option before the epidemic of COVID-19. In the postepidemic era, under the double carbon (carbon neutral and carbon peaking) policy, the advantage of low fuel consumption for the LNG ships disappeared due to the increase in LNG prices, and the NPV advantage of MGO ships becomes significant. [ FROM AUTHOR] Copyright of Mathematical Problems in Engineering is the property of Hindawi Limited and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

8.
biorxiv; 2022.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2022.07.23.501111

ABSTRACT

Haplotype network is becoming popular due to its increasing use in analyzing genealogical relationships of closely related genomes. We newly proposed McAN, a minimum-cost arborescence based haplotype network con-struction algorithm, by considering mutation spectrum history (mutations in ancestry haplotype should be contained in descendant haplotype), node size (corresponding to sample count for a given node) and sampling time. McAN is two orders of magnitude faster than the state-of-the-art algorithms, making it suitable for analyzation of massive se-quences. Availability: Source code is written in C/C++ and available at https://github.com/Theory-Lun/McAN and https://ngdc.cncb.ac.cn/biocode/tools/BT007301 under the MIT license. The online web service of McAN is available at https://ngdc.cncb.ac.cn/ncov/online/tool/haplotype. SARS-CoV-2 dataset are available at https://ngdc.cncb.ac.cn/ncov/.

9.
Front Immunol ; 12: 764949, 2021.
Article in English | MEDLINE | ID: covidwho-1674330

ABSTRACT

We identified SARS-CoV-2 specific antigen epitopes by HLA-A2 binding affinity analysis and characterized their ability to activate T cells. As the pandemic continues, variations in SARS-CoV-2 virus strains have been found in many countries. In this study, we directly assess the immune response to SARS-CoV-2 epitope variants. We first predicted potential HLA-A*02:01-restricted CD8+ T-cell epitopes of SARS-CoV-2. Using the T2 cell model, HLA-A*02:01-restricted T-cell epitopes were screened for their binding affinity and ability to activate T cells. Subsequently, we examined the identified epitope variations and analyzed their impact on immune response. Here, we identified specific HLA-A2-restricted T-cell epitopes in the spike protein of SARS-CoV-2. Seven epitope peptides were confirmed to bind with HLA-A*02:01 and potentially be presented by antigen-presenting cells to induce host immune responses. Tetramers containing these peptides could interact with specific CD8+ T cells from convalescent COVID-19 patients, and one dominant epitope (n-Sp1) was defined. These epitopes could activate and generate epitope-specific T cells in vitro, and those activated T cells showed cytolytic activity toward target cells. Meanwhile, n-Sp1 epitope variant 5L>F significantly decreased the proportion of specific T-cell activation; n-Sp1 epitope 8L>V variant showed significantly reduced binding to HLA-A*02:01 and decreased proportion of n-Sp1-specific CD8+ T cell, which potentially contributes to the immune escape of SARS-CoV-2. Our data indicate that the variation of a dominant epitope will cause the deficiency of HLA-A*02:01 binding and T-cell activation, which subsequently requires the formation of a new CD8+ T-cell immune response in COVID-19 patients.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Epitopes, T-Lymphocyte/immunology , HLA-A2 Antigen/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Amino Acid Sequence , Antigen Presentation , Antigenic Variation , COVID-19/immunology , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/genetics , Female , Humans , Immune Evasion , Lymphocyte Activation , Male , Middle Aged , Molecular Docking Simulation , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
10.
Genomics Proteomics Bioinformatics ; 18(6): 648-663, 2020 12.
Article in English | MEDLINE | ID: covidwho-1077907

ABSTRACT

COVID-19 and its causative pathogen SARS-CoV-2 have rushed the world into a staggering pandemic in a few months, and a global fight against both has been intensifying. Here, we describe an analysis procedure where genome composition and its variables are related, through the genetic code to molecular mechanisms, based on understanding of RNA replication and its feedback loop from mutation to viral proteome sequence fraternity including effective sites on the replicase-transcriptase complex. Our analysis starts with primary sequence information, identity-based phylogeny based on 22,051 SARS-CoV-2 sequences, and evaluation of sequence variation patterns as mutation spectra and its 12 permutations among organized clades. All are tailored to two key mechanisms: strand-biased and function-associated mutations. Our findings are listed as follows: 1) The most dominant mutation is C-to-U permutation, whose abundant second-codon-position counts alter amino acid composition toward higher molecular weight and lower hydrophobicity, albeit assumed most slightly deleterious. 2) The second abundance group includes three negative-strand mutations (U-to-C, A-to-G, and G-to-A) and a positive-strand mutation (G-to-U) due to DNA repair mechanisms after cellular abasic events. 3) A clade-associated biased mutation trend is found attributable to elevated level of negative-sense strand synthesis. 4) Within-clade permutation variation is very informative for associating non-synonymous mutations and viral proteome changes. These findings demand a platform where emerging mutations are mapped onto mostly subtle but fast-adjusting viral proteomes and transcriptomes, to provide biological and clinical information after logical convergence for effective pharmaceutical and diagnostic applications. Such actions are in desperate need, especially in the middle of the War against COVID-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Evolution, Molecular , Genome, Viral , Humans , Mutation
11.
Ophthalmic Epidemiol ; 28(5): 369-375, 2021 10.
Article in English | MEDLINE | ID: covidwho-1045955

ABSTRACT

Objecive: This study aimed to evaluate whether Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) can be detected in the tears in the eyes of Coronavirus Disease 2019 (COVID-2019) infected patients and compare the detection consistency of two simultaneously collected samples, from the tears and throat swabs.Methods: A total of 35 COVID-2019 patients were included in this cross-sectional case series study. Throat samples from all enrolled patients were collected with sampling swab, and simultaneously, tear samples were collected with sampling swab from 9 patients (No.1-9) and with Schirmer's strip from the remaining patients (No.10-35) (bilateral eyes for all patients). Sample collecting and testing were performed in three separate time points: first from patients No.1-9, second from patients No.10-29, and third from patients No. 30-35. Reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay was performed.Results: Among enrolled patients, 29 (No.1-29) had mild or moderate clinical symptoms and 6 (No.30-35) had severe symptoms. The mean time interval from the sample collection day to diagnosis confirmation day was 9.71 ± 6.50 days (ranged from 3 to 29 days). None of the patients had conjunctivitis. Nineteen out of 35 (54.3%) throat samples presented positive Rt-PCR results. Three (no.13,21,31) out of 35 (8.6%) tear samples presented positive RT-PCR results. Two (no.21, 31) of these three patients were throat swab positive and one (No. 13) was negative. The consistency analysis indicated that tears and throat samples showed poor consistency (Kappa = -0.009, P = .9).The cycle threshold value (Ct-value) of tear samples collected by sampling swab was significantly higher than that by Schirmer's strip (t = 2.288, P = .03).Conclusion: In spite of the low SARS-CoV-2 positive detection rate of tear samples from COVID-2019 patients, we cannot fully rule out the transmission by ocular surface. Whether tear testing can be used as an aid in judging of SARS-CoV-2 infection need further investigation.


Subject(s)
COVID-19 , SARS-CoV-2 , Cross-Sectional Studies , Humans , Pharynx , RNA, Viral
12.
Genomics Proteomics Bioinformatics ; 18(6): 749-759, 2020 12.
Article in English | MEDLINE | ID: covidwho-987765

ABSTRACT

On January 22, 2020, China National Center for Bioinformation (CNCB) released the 2019 Novel Coronavirus Resource (2019nCoVR), an open-access information resource for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). 2019nCoVR features a comprehensive integration of sequence and clinical information for all publicly available SARS-CoV-2 isolates, which are manually curated with value-added annotations and quality evaluated by an automated in-house pipeline. Of particular note, 2019nCoVR offers systematic analyses to generate a dynamic landscape of SARS-CoV-2 genomic variations at a global scale. It provides all identified variants and their detailed statistics for each virus isolate, and congregates the quality score, functional annotation, and population frequency for each variant. Spatiotemporal change for each variant can be visualized and historical viral haplotype network maps for the course of the outbreak are also generated based on all complete and high-quality genomes available. Moreover, 2019nCoVR provides a full collection of SARS-CoV-2 relevant literature on the coronavirus disease 2019 (COVID-19), including published papers from PubMed as well as preprints from services such as bioRxiv and medRxiv through Europe PMC. Furthermore, by linking with relevant databases in CNCB, 2019nCoVR offers data submission services for raw sequence reads and assembled genomes, and data sharing with NCBI. Collectively, SARS-CoV-2 is updated daily to collect the latest information on genome sequences, variants, haplotypes, and literature for a timely reflection, making 2019nCoVR a valuable resource for the global research community. 2019nCoVR is accessible at https://bigd.big.ac.cn/ncov/.


Subject(s)
COVID-19 , SARS-CoV-2 , Genome, Viral , Genomics , Haplotypes , Humans
13.
Zool Res ; 41(6): 705-708, 2020 Nov 18.
Article in English | MEDLINE | ID: covidwho-982981

ABSTRACT

Since the first reported severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in December 2019, coronavirus disease 2019 (COVID-19) has become a global pandemic, spreading to more than 200 countries and regions worldwide. With continued research progress and virus detection, SARS-CoV-2 genomes and sequencing data have been reported and accumulated at an unprecedented rate. To meet the need for fast analysis of these genome sequences, the National Genomics Data Center (NGDC) of the China National Center for Bioinformation (CNCB) has established an online coronavirus analysis platform, which includes de novoassembly, BLAST alignment, genome annotation, variant identification, and variant annotation modules. The online analysis platform can be freely accessed at the 2019 Novel Coronavirus Resource (2019nCoVR) (https://bigd.big.ac.cn/ncov/online/tools).


Subject(s)
Betacoronavirus/genetics , Computational Biology/methods , Coronavirus Infections/diagnosis , Genome, Viral/genetics , Genomics/methods , High-Throughput Nucleotide Sequencing/methods , Pneumonia, Viral/diagnosis , Animals , Betacoronavirus/classification , Betacoronavirus/physiology , COVID-19 , China , Computational Biology/organization & administration , Coronavirus Infections/virology , Genetic Variation , Humans , Internet , Molecular Sequence Annotation , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2
14.
Anal Methods ; 12(44): 5392-5396, 2020 11 28.
Article in English | MEDLINE | ID: covidwho-894424

ABSTRACT

Multiplex PCR encounters difficulties in primer designing with all the primer pairs working at the same annealing temperature. In this study, we have developed a double-strand primer-mediated multiple strand displacement reaction for the detection of SARS-COV-2 ORF, N and E genes (as examples). The double primer is composed of a 5'-modified fluorophore strand, which does not impact polymerase extension and a 3'-modified quencher strand, which cannot impact elongation. At the annealing temperature, the fluorophore strand combined with the template, extended and resulted in fluorescence signal release. Results showed that the double-strand primer relatively exhibits a wide annealing temperature range and good compatibility between three pairs of primers and probes. These merits allow the simple and multiplex real-time fluorescence quantification of nucleic acids. The detection limit was 400 copies/mL, and the detection time was approximately 2 h. In addition to its extreme specificity and simplicity, this method has a wide range of applications such as multiple PCR and SNP detection.


Subject(s)
Coronavirus Envelope Proteins/genetics , Coronavirus Nucleocapsid Proteins/genetics , DNA, Viral/analysis , Multiplex Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/methods , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing/methods , DNA Primers/chemistry , DNA Primers/genetics , Humans , Limit of Detection , Phosphoproteins/genetics , SARS-CoV-2/chemistry
15.
biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.08.30.273920

ABSTRACT

The COVID-19 pandemic presents an urgent health crisis. Human neutralizing antibodies (hNAbs) that target the host ACE2 receptor-binding domain (RBD) of the SARS-CoV-2 spike1-5 show therapeutic promise and are being evaluated clincally6-8. To determine structural correlates of SARS-CoV-2 neutralization, we solved 8 new structures of distinct COVID-19 hNAbs5 in complex with SARS-CoV-2 spike trimer or RBD. Structural comparisons allowed classification into categories: (1) VH3-53 hNAbs with short CDRH3s that block ACE2 and bind only to "up" RBDs, (2) ACE2-blocking hNAbs that bind both "up" and "down" RBDs and can contact adjacent RBDs, (3) hNAbs that bind outside the ACE2 site and recognize "up" and "down" RBDs, and (4) Previously-described antibodies that do not block ACE2 and bind only "up" RBDs9. Class 2 comprised four hNAbs whose epitopes bridged RBDs, including a VH3-53 hNAb that used a long CDRH3 with a hydrophobic tip to bridge between adjacent "down" RBDs, thereby locking spike into a closed conformation. Epitope/paratope mapping revealed few interactions with host-derived N-glycans and minor contributions of antibody somatic hypermutations to epitope contacts. Affinity measurements and mapping of naturally-occurring and in vitro-selected spike mutants in 3D provided insight into the potential for SARS-CoV-2 escape from antibodies elicited during infection or delivered therapeutically. These classifications and structural analyses provide rules for assigning current and future human RBD-targeting antibodies into classes, evaluating avidity effects, suggesting combinations for clinical use, and providing insight into immune responses against SARS-CoV-2.


Subject(s)
COVID-19
16.
biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.08.30.273235

ABSTRACT

On 22 January 2020, the National Genomics Data Center (NGDC), part of the China National Center for Bioinformation (CNCB), created the 2019 Novel Coronavirus Resource (2019nCoVR), an open-access SARS-CoV-2 information resource. 2019nCoVR features a comprehensive integration of sequence and clinical information for all publicly available SARS-CoV-2 isolates, which are manually curated with value-added annotations and quality evaluated by our in-house automated pipeline. Of particular note, 2019nCoVR performs systematic analyses to generate a dynamic landscape of SARS-CoV-2 genomic variations at a global scale. It provides all identified variants and detailed statistics for each virus isolate, and congregates the quality score, functional annotation, and population frequency for each variant. It also generates visualization of the spatiotemporal change for each variant and yields historical viral haplotype network maps for the course of the outbreak from all complete and high-quality genomes. Moreover, 2019nCoVR provides a full collection of SARS-CoV-2 relevant literature on COVID-19 (Coronavirus Disease 2019), including published papers from PubMed as well as preprints from services such as bioRxiv and medRxiv through Europe PMC. Furthermore, by linking with relevant databases in CNCB-NGDC, 2019nCoVR offers data submission services for raw sequence reads and assembled genomes, and data sharing with National Center for Biotechnology Information. Collectively, all SARS-CoV-2 genome sequences, variants, haplotypes and literature are updated daily to provide timely information, making 2019nCoVR a valuable resource for the global research community. 2019nCoVR is accessible at https://bigd.big.ac.cn/ncov/.


Subject(s)
COVID-19
17.
biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.08.30.274464

ABSTRACT

Global health has been threatened by the COVID-19 pandemic, caused by the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2)1. Although considered primarily a respiratory infection, many COVID-19 patients also suffer severe cardiovascular disease2-4. Improving patient care critically relies on understanding if cardiovascular pathology is caused directly by viral infection of cardiac cells or indirectly via systemic inflammation and/or coagulation abnormalities3,5-9. Here we examine the cardiac tropism of SARS-CoV-2 using human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) and three-dimensional engineered heart tissues (3D-EHTs). We observe that hPSC-CMs express the viral receptor ACE2 and other viral processing factors, and that SARS-CoV-2 readily infects and replicates within hPSC-CMs, resulting in rapid cell death. Moreover, infected hPSC-CMs show a progressive impairment in both electrophysiological and contractile properties. Thus, COVID-19-related cardiac symptoms likely result from a direct cardiotoxic effect of SARS-CoV-2. Long-term cardiac complications might be possible sequelae in patients who recover from this illness.


Subject(s)
COVID-19
18.
biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.08.29.272864

ABSTRACT

We describe a mammalian cell-based assay capable of identifying coronavirus 3CL protease (3CLpro) inhibitors without requiring the use of live virus. By enabling the facile testing of compounds across a range of coronavirus 3CLpro enzymes, including the one from SARS-CoV-2, we are able to quickly identify compounds with broad or narrow spectra of activity. We further demonstrate the utility of our approach by performing a curated compound screen along with structure-activity profiling of a series of small molecules to identify compounds with antiviral activity. Throughout these studies, we observed concordance between data emerging from this assay and from live virus assays. By democratizing the testing of 3CL inhibitors to enable screening in the majority of laboratories rather than the few with extensive biosafety infrastructure, we hope to expedite the search for coronavirus 3CL protease inhibitors, to address the current epidemic and future ones that will inevitably arise.

19.
biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.08.29.273425

ABSTRACT

The human placenta is increasingly a focus of research related to early child development and the impact of maternal hyperimmune states. The ability to model human trophectoderm disease states from human pluripotent stem cells, the nature of human pluripotent stem cell potency and the mechanisms regulating human trophectoderm specification remains poorly understood. Recent work suggests that only the naive state can give rise to trophectoderm and that primed iPSC generate mixed amnionic and mesoderm lineages. Here we identify conditions that efficiently drive the specification of primed iPSC to trophectoderm, named Trophoblast Stem Cell (TSC). iPS-derived-TSC share transcriptional, morphological and functional characteristics with human in vivo cytotrophoblasts including activation of human endogenous retroviruses, expression of COVID-19 associated host factors and generation of multinucleated syncytiotrophoblasts with a large fusion index. At high densities in 5% O2, iPS-derived-TSC form villi-like structures and express extravillous and syncytiotrophoblast proteins HCG-{beta} and HLA-G. Using temporal single cell RNAseq, we define the molecular changes associated with specification under three separate conditions: 1) BMP4, 2) BMP4 and inhibition of WNT, 3) activation of EGF and WNT, inhibition of TGFbeta, HDAC and ROCK signaling (named TSC). With 9,821 high-quality single cell transcriptomes, we find that BMP4 gives rise to mesenchymal cells while TS conditions lacking exogenous BMP4 generate a stable proliferating cell type that is highly similar to six week placenta cytotrophoblasts. TFAP2A programs the specification of primed iPS cells to TSC without transitioning through a naive state. TSC specification independent of exogenous BMP4 will allow for robust and reproducible studies of the cytotrophoblast component of human placenta.


Subject(s)
COVID-19
20.
biorxiv; 2020.
Preprint in English | bioRxiv | ID: ppzbmed-10.1101.2020.08.26.267781

ABSTRACT

COVID-19 and its causative pathogen SARS-CoV-2 have rushed the world into a staggering pandemic in a few months and a global fight against both is still going on. Here, we describe an analysis procedure where genome composition and its variables are related, through the genetic code, to molecular mechanisms based on understanding of RNA replication and its feedback loop from mutation to viral proteome sequence fraternity including effective sites on replicase-transcriptase complex. Our analysis starts with primary sequence information and identity-based phylogeny based on 22,051 SARS-CoV-2 genome sequences and evaluation of sequence variation patterns as mutation spectrum and its 12 permutations among organized clades tailored to two key mechanisms: strand-biased and function-associated mutations. Our findings include: (1) The most dominant mutation is C-to-U permutation whose abundant second-codon-position counts alter amino acid composition toward higher molecular weight and lower hydrophobicity albeit assumed most slightly deleterious. (2) The second abundance group includes: three negative-strand mutations U-to-C, A-to-G, G-to-A and a positive-strand mutation G-to-U generated through an identical mechanism as C-to-U. (3) A clade-associated and biased mutation trend is found attributable to elevated level of the negative-sense strand synthesis. (4) Within-clade permutation variation is very informative for associating non-synonymous mutations and viral proteome changes. These findings demand a bioinformatics platform where emerging mutations are mapped on to mostly subtle but fast-adjusting viral proteomes and transcriptomes to provide biological and clinical information after logical convergence for effective pharmaceutical and diagnostic applications. Such thoughts and actions are in desperate need, especially in the middle of the War against COVID-19.


Subject(s)
COVID-19
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