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1.
PLoS Biol ; 19(3): e3001158, 2021 03.
Article in English | MEDLINE | ID: covidwho-1156073

ABSTRACT

Since its emergence in December 2019, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread globally and become a major public health burden. Despite its close phylogenetic relationship to SARS-CoV, SARS-CoV-2 exhibits increased human-to-human transmission dynamics, likely due to efficient early replication in the upper respiratory epithelium of infected individuals. Since different temperatures encountered in the human upper and lower respiratory tract (33°C and 37°C, respectively) have been shown to affect the replication kinetics of several respiratory viruses, as well as host innate immune response dynamics, we investigated the impact of temperature on SARS-CoV-2 and SARS-CoV infection using the primary human airway epithelial cell culture model. SARS-CoV-2, in contrast to SARS-CoV, replicated to higher titers when infections were performed at 33°C rather than 37°C. Although both viruses were highly sensitive to type I and type III interferon pretreatment, a detailed time-resolved transcriptome analysis revealed temperature-dependent interferon and pro-inflammatory responses induced by SARS-CoV-2 that were inversely proportional to its replication efficiency at 33°C or 37°C. These data provide crucial insight on pivotal virus-host interaction dynamics and are in line with characteristic clinical features of SARS-CoV-2 and SARS-CoV, as well as their respective transmission efficiencies.


Subject(s)
Gene Expression Profiling/methods , Gene Expression Regulation, Viral/genetics , SARS Virus/genetics , SARS-CoV-2/genetics , Animals , Antiviral Agents/pharmacology , Cells, Cultured , Chlorocebus aethiops , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelial Cells/virology , Gene Expression Regulation, Viral/drug effects , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Humans , Interferons/pharmacology , SARS Virus/drug effects , SARS Virus/physiology , SARS-CoV-2/drug effects , SARS-CoV-2/physiology , Species Specificity , Temperature , Vero Cells , Virus Replication/drug effects , Virus Replication/genetics
2.
Am J Ophthalmol Case Rep ; 22: 101074, 2021 Jun.
Article in English | MEDLINE | ID: covidwho-1135233

ABSTRACT

PURPOSE: To report a case of a patient presenting with unilateral keratouveitis associated with ocular hypertension six weeks after being discharged from the hospital for COVID-19. Ocular specimens were obtained for testing. OBSERVATIONS: A 69-year-old African American woman developed poor vision while hospitalized for COVID-19 in April but did not seek ophthalmic care until end of May. She had an edematous cornea, stromal keratitis, and highly elevated intraocular pressure by June. After lack of response to oral valacyclovir, aqueous fluid and swabs of her conjunctiva and limbal epithelium with corneal epithelium anterior to the limbus were sent for real-time polymerase chain reaction (PCR) for herpes simplex virus, herpes zoster virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epithelium from the cornea and limbus was positive for SARS-CoV-2 by PCR; specimens from the other two ocular sites were negative. All specimens were negative for herpes simplex virus and varicella zoster virus. The patient refused further treatment despite intraocular pressure above 50 mm Hg at last follow-up. CONCLUSIONS AND IMPORTANCE: Although SARS-CoV-2 and severe acute respiratory syndrome coronavirus (SARS-CoV) have been detected by PCR in the conjunctiva and tears of patients with acute respiratory infection, presence in corneal tissue has not been described. In addition, no one has studied whether ocular tissues in convalesced patients can harbor viral RNA. Here we describe unilateral keratouveitis in a convalesced patient whose corneal epithelium/limbal tissue was positive for SARS-CoV-2 by PCR. Further investigation is required to determine whether active viral replication or viral remnants account for this result.

3.
Cell Mol Gastroenterol Hepatol ; 11(3): 771-781, 2021.
Article in English | MEDLINE | ID: covidwho-808973

ABSTRACT

BACKGROUND AND AIMS: Besides prominent respiratory involvement, gastrointestinal manifestations are commonly reported in Coronavirus Disease 2019 (COVID-19) patients. We compared infection of ex vivo human intestinal tissues by SARS-CoV-2 and SARS-CoV with respect to their replication kinetics and immune activation profile. METHODS: Human intestinal tissues were obtained from patients while undergoing surgical operations at Queen Mary Hospital, Hong Kong. Upon surgical removal, the tissues were immediately processed and infected with SARS-CoV-2 or SARS-CoV. Replication kinetics were determined with immunohistochemistry, qRT-PCR, and plaque assays. Immune activation in the infected intestinal tissues was assessed by detecting the gene expression of interferons and representative pro-inflammatory cytokines and chemokines. RESULTS: SARS-CoV-2 could infect and productively replicate in the ex vivo human intestinal tissues with release of infectious virus particles, but not in ex vivo human liver and kidney tissues. Importantly, SARS-CoV-2 replicated less efficiently than SARS-CoV, induced less cytopathology in the human intestinal epithelium, and induced a more robust innate immune response including the activation of both type I and type III interferons, than SARS-CoV in human intestinal tissues. CONCLUSION: Using the ex vivo human intestinal tissues as a physiologically relevant model, our data indicated that SARS-CoV-2 could productively replicate in the human gut and suggested that the gastrointestinal tract might serve as an alternative route of virus dissemination. SARS-CoV-2 replicated less efficiently and induced less cytopathology than SARS-CoV in keeping with the clinical observations reported for COVID-19 and SARS, which might be the result of a more robust immune activation by SARS-CoV-2 than SARS-CoV in the human intestine.


Subject(s)
COVID-19/immunology , COVID-19/virology , Immunity, Innate/immunology , Intestinal Mucosa/virology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Aged , Aged, 80 and over , Female , Humans , In Vitro Techniques , Male , Middle Aged , SARS Virus/pathogenicity , Virus Replication/immunology , Virus Replication/physiology
4.
Protein Sci ; 29(10): 2038-2042, 2020 10.
Article in English | MEDLINE | ID: covidwho-725698

ABSTRACT

The Envelope protein (E) is one of the four structural proteins encoded by the genome of SARS-CoV and SARS-CoV-2 Coronaviruses. It is an integral membrane protein, highly expressed in the host cell, which is known to have an important role in Coronaviruses maturation, assembly and virulence. The E protein presents a PDZ-binding motif at its C-terminus. One of the key interactors of the E protein in the intracellular environment is the PDZ containing protein PALS1. This interaction is known to play a key role in the SARS-CoV pathology and suspected to affect the integrity of the lung epithelia. In this paper we measured and compared the affinity of peptides mimicking the E protein from SARS-CoV and SARS-CoV-2 for the PDZ domain of PALS1, through equilibrium and kinetic binding experiments. Our results support the hypothesis that the increased virulence of SARS-CoV-2 compared to SARS-CoV may rely on the increased affinity of its Envelope protein for PALS1.


Subject(s)
Betacoronavirus/metabolism , Coronavirus Infections/metabolism , Membrane Proteins/metabolism , Nucleoside-Phosphate Kinase/metabolism , Pneumonia, Viral/metabolism , SARS Virus/metabolism , Severe Acute Respiratory Syndrome/metabolism , Viral Envelope Proteins/metabolism , Amino Acid Sequence , Betacoronavirus/chemistry , Binding Sites , COVID-19 , Coronavirus Envelope Proteins , Coronavirus Infections/virology , Humans , Membrane Proteins/chemistry , Models, Molecular , Nucleoside-Phosphate Kinase/chemistry , PDZ Domains , Pandemics , Peptides/chemistry , Peptides/metabolism , Pneumonia, Viral/virology , Protein Binding , SARS Virus/chemistry , SARS-CoV-2 , Severe Acute Respiratory Syndrome/virology , Viral Envelope Proteins/chemistry
5.
Lancet Respir Med ; 8(7): 687-695, 2020 07.
Article in English | MEDLINE | ID: covidwho-197584

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019, causing a respiratory disease (coronavirus disease 2019, COVID-19) of varying severity in Wuhan, China, and subsequently leading to a pandemic. The transmissibility and pathogenesis of SARS-CoV-2 remain poorly understood. We evaluate its tissue and cellular tropism in human respiratory tract, conjunctiva, and innate immune responses in comparison with other coronavirus and influenza virus to provide insights into COVID-19 pathogenesis. METHODS: We isolated SARS-CoV-2 from a patient with confirmed COVID-19, and compared virus tropism and replication competence with SARS-CoV, Middle East respiratory syndrome-associated coronavirus (MERS-CoV), and 2009 pandemic influenza H1N1 (H1N1pdm) in ex-vivo cultures of human bronchus (n=5) and lung (n=4). We assessed extrapulmonary infection using ex-vivo cultures of human conjunctiva (n=3) and in-vitro cultures of human colorectal adenocarcinoma cell lines. Innate immune responses and angiotensin-converting enzyme 2 expression were investigated in human alveolar epithelial cells and macrophages. In-vitro studies included the highly pathogenic avian influenza H5N1 virus (H5N1) and mock-infected cells as controls. FINDINGS: SARS-CoV-2 infected ciliated, mucus-secreting, and club cells of bronchial epithelium, type 1 pneumocytes in the lung, and the conjunctival mucosa. In the bronchus, SARS-CoV-2 replication competence was similar to MERS-CoV, and higher than SARS-CoV, but lower than H1N1pdm. In the lung, SARS-CoV-2 replication was similar to SARS-CoV and H1N1pdm, but was lower than MERS-CoV. In conjunctiva, SARS-CoV-2 replication was greater than SARS-CoV. SARS-CoV-2 was a less potent inducer of proinflammatory cytokines than H5N1, H1N1pdm, or MERS-CoV. INTERPRETATION: The conjunctival epithelium and conducting airways appear to be potential portals of infection for SARS-CoV-2. Both SARS-CoV and SARS-CoV-2 replicated similarly in the alveolar epithelium; SARS-CoV-2 replicated more extensively in the bronchus than SARS-CoV. These findings provide important insights into the transmissibility and pathogenesis of SARS-CoV-2 infection and differences with other respiratory pathogens. FUNDING: US National Institute of Allergy and Infectious Diseases, University Grants Committee of Hong Kong Special Administrative Region, China; Health and Medical Research Fund, Food and Health Bureau, Government of Hong Kong Special Administrative Region, China.


Subject(s)
Betacoronavirus/immunology , Conjunctiva/virology , Coronavirus Infections/immunology , Immunity, Innate/immunology , Pneumonia, Viral/immunology , Respiratory System/virology , Viral Tropism/physiology , Virus Replication/physiology , Adult , Aged , Aged, 80 and over , Betacoronavirus/physiology , COVID-19 , Conjunctiva/immunology , Conjunctiva/physiopathology , Coronavirus Infections/physiopathology , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/physiopathology , Respiratory Mucosa/immunology , Respiratory Mucosa/physiopathology , Respiratory Mucosa/virology , Respiratory System/immunology , Respiratory System/physiopathology , SARS-CoV-2
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