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1.
Nature ; 603(7902): 706-714, 2022 03.
Article in English | MEDLINE | ID: covidwho-1764186

ABSTRACT

The SARS-CoV-2 Omicron BA.1 variant emerged in 20211 and has multiple mutations in its spike protein2. Here we show that the spike protein of Omicron has a higher affinity for ACE2 compared with Delta, and a marked change in its antigenicity increases Omicron's evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralizing antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralization. Importantly, the antiviral drugs remdesivir and molnupiravir retain efficacy against Omicron BA.1. Replication was similar for Omicron and Delta virus isolates in human nasal epithelial cultures. However, in lung cells and gut cells, Omicron demonstrated lower replication. Omicron spike protein was less efficiently cleaved compared with Delta. The differences in replication were mapped to the entry efficiency of the virus on the basis of spike-pseudotyped virus assays. The defect in entry of Omicron pseudotyped virus to specific cell types effectively correlated with higher cellular RNA expression of TMPRSS2, and deletion of TMPRSS2 affected Delta entry to a greater extent than Omicron. Furthermore, drug inhibitors targeting specific entry pathways3 demonstrated that the Omicron spike inefficiently uses the cellular protease TMPRSS2, which promotes cell entry through plasma membrane fusion, with greater dependency on cell entry through the endocytic pathway. Consistent with suboptimal S1/S2 cleavage and inability to use TMPRSS2, syncytium formation by the Omicron spike was substantially impaired compared with the Delta spike. The less efficient spike cleavage of Omicron at S1/S2 is associated with a shift in cellular tropism away from TMPRSS2-expressing cells, with implications for altered pathogenesis.


Subject(s)
COVID-19/pathology , COVID-19/virology , Membrane Fusion , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Serine Endopeptidases/metabolism , Virus Internalization , Adult , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19 Vaccines/immunology , Cell Line , Cell Membrane/metabolism , Cell Membrane/virology , Chlorocebus aethiops , Convalescence , Female , Humans , Immune Sera/immunology , Intestines/pathology , Intestines/virology , Lung/pathology , Lung/virology , Male , Middle Aged , Mutation , Nasal Mucosa/pathology , Nasal Mucosa/virology , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism , Tissue Culture Techniques , Virulence , Virus Replication
2.
Trends Genet ; 37(7): 625-630, 2021 07.
Article in English | MEDLINE | ID: covidwho-1187872

ABSTRACT

Comprehensively characterizing the cellular composition and organization of tissues has been a long-term scientific challenge that has limited our ability to study fundamental and clinical aspects of human physiology. The Human Cell Atlas (HCA) is a global collaborative effort to create a reference map of all human cells as a basis for both understanding human health and diagnosing, monitoring, and treating disease. Many aspects of the HCA are analogous to the Human Genome Project (HGP), whose completion presents a major milestone in modern biology. To commemorate the HGP's 20-year anniversary of completion, we discuss the launch of the HCA in light of the HGP, and highlight recent progress by the HCA consortium.


Subject(s)
Cell Lineage/genetics , Cell Physiological Phenomena/genetics , Cells/classification , Genome, Human/genetics , Human Genome Project , Humans
4.
Nat Med ; 27(5): 892-903, 2021 05.
Article in English | MEDLINE | ID: covidwho-1152866

ABSTRACT

Despite signs of infection-including taste loss, dry mouth and mucosal lesions such as ulcerations, enanthema and macules-the involvement of the oral cavity in coronavirus disease 2019 (COVID-19) is poorly understood. To address this, we generated and analyzed two single-cell RNA sequencing datasets of the human minor salivary glands and gingiva (9 samples, 13,824 cells), identifying 50 cell clusters. Using integrated cell normalization and annotation, we classified 34 unique cell subpopulations between glands and gingiva. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral entry factors such as ACE2 and TMPRSS members were broadly enriched in epithelial cells of the glands and oral mucosae. Using orthogonal RNA and protein expression assessments, we confirmed SARS-CoV-2 infection in the glands and mucosae. Saliva from SARS-CoV-2-infected individuals harbored epithelial cells exhibiting ACE2 and TMPRSS expression and sustained SARS-CoV-2 infection. Acellular and cellular salivary fractions from asymptomatic individuals were found to transmit SARS-CoV-2 ex vivo. Matched nasopharyngeal and saliva samples displayed distinct viral shedding dynamics, and salivary viral burden correlated with COVID-19 symptoms, including taste loss. Upon recovery, this asymptomatic cohort exhibited sustained salivary IgG antibodies against SARS-CoV-2. Collectively, these data show that the oral cavity is an important site for SARS-CoV-2 infection and implicate saliva as a potential route of SARS-CoV-2 transmission.


Subject(s)
COVID-19/virology , Mouth/virology , SARS-CoV-2/isolation & purification , Saliva/virology , Angiotensin-Converting Enzyme 2/analysis , Asymptomatic Infections , COVID-19/etiology , Humans , Serine Endopeptidases/analysis , Taste Disorders/etiology , Taste Disorders/virology , Virus Replication
5.
Sci Adv ; 7(7)2021 02.
Article in English | MEDLINE | ID: covidwho-1084597

ABSTRACT

We present INSIGHT [isothermal NASBA (nucleic acid sequence-based amplification) sequencing-based high-throughput test], a two-stage coronavirus disease 2019 testing strategy, using a barcoded isothermal NASBA reaction. It combines point-of-care diagnosis with next-generation sequencing, aiming to achieve population-scale testing. Stage 1 allows a quick decentralized readout for early isolation of presymptomatic or asymptomatic patients. It gives results within 1 to 2 hours, using either fluorescence detection or a lateral flow readout, while simultaneously incorporating sample-specific barcodes. The same reaction products from potentially hundreds of thousands of samples can then be pooled and used in a highly multiplexed sequencing-based assay in stage 2. This second stage confirms the near-patient testing results and facilitates centralized data collection. The 95% limit of detection is <50 copies of viral RNA per reaction. INSIGHT is suitable for further development into a rapid home-based, point-of-care assay and is potentially scalable to the population level.


Subject(s)
COVID-19 Nucleic Acid Testing , COVID-19 , High-Throughput Nucleotide Sequencing , Point-of-Care Testing , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/genetics , Humans
6.
Nature ; 588(7838): 466-472, 2020 12.
Article in English | MEDLINE | ID: covidwho-1075229

ABSTRACT

Cardiovascular disease is the leading cause of death worldwide. Advanced insights into disease mechanisms and therapeutic strategies require a deeper understanding of the molecular processes involved in the healthy heart. Knowledge of the full repertoire of cardiac cells and their gene expression profiles is a fundamental first step in this endeavour. Here, using state-of-the-art analyses of large-scale single-cell and single-nucleus transcriptomes, we characterize six anatomical adult heart regions. Our results highlight the cellular heterogeneity of cardiomyocytes, pericytes and fibroblasts, and reveal distinct atrial and ventricular subsets of cells with diverse developmental origins and specialized properties. We define the complexity of the cardiac vasculature and its changes along the arterio-venous axis. In the immune compartment, we identify cardiac-resident macrophages with inflammatory and protective transcriptional signatures. Furthermore, analyses of cell-to-cell interactions highlight different networks of macrophages, fibroblasts and cardiomyocytes between atria and ventricles that are distinct from those of skeletal muscle. Our human cardiac cell atlas improves our understanding of the human heart and provides a valuable reference for future studies.


Subject(s)
Myocardium/cytology , Single-Cell Analysis , Transcriptome , Adipocytes/classification , Adipocytes/metabolism , Adult , Angiotensin-Converting Enzyme 2/analysis , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Epithelial Cells/classification , Epithelial Cells/metabolism , Epithelium , Female , Fibroblasts/classification , Fibroblasts/metabolism , Gene Expression Profiling , Genome-Wide Association Study , Heart Atria/anatomy & histology , Heart Atria/cytology , Heart Atria/innervation , Heart Ventricles/anatomy & histology , Heart Ventricles/cytology , Heart Ventricles/innervation , Homeostasis/immunology , Humans , Macrophages/immunology , Macrophages/metabolism , Male , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Myocytes, Cardiac/classification , Myocytes, Cardiac/metabolism , Neurons/classification , Neurons/metabolism , Pericytes/classification , Pericytes/metabolism , Receptors, Coronavirus/analysis , Receptors, Coronavirus/genetics , Receptors, Coronavirus/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Stromal Cells/classification , Stromal Cells/metabolism
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