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1.
EMBO Mol Med ; 13(4): e13191, 2021 04 09.
Article in English | MEDLINE | ID: covidwho-1068062

ABSTRACT

SARS-CoV-2, the agent that causes COVID-19, invades epithelial cells, including those of the respiratory and gastrointestinal mucosa, using angiotensin-converting enzyme-2 (ACE2) as a receptor. Subsequent inflammation can promote rapid virus clearance, but severe cases of COVID-19 are characterized by an inefficient immune response that fails to clear the infection. Using primary epithelial organoids from human colon, we explored how the central antiviral mediator IFN-γ, which is elevated in COVID-19, affects epithelial cell differentiation, ACE2 expression, and susceptibility to infection with SARS-CoV-2. In mouse and human colon, ACE2 is mainly expressed by surface enterocytes. Inducing enterocyte differentiation in organoid culture resulted in increased ACE2 production. IFN-γ treatment promoted differentiation into mature KRT20+ enterocytes expressing high levels of ACE2, increased susceptibility to SARS-CoV-2 infection, and resulted in enhanced virus production in infected cells. Similarly, infection-induced epithelial interferon signaling promoted enterocyte maturation and enhanced ACE2 expression. We here reveal a mechanism by which IFN-γ-driven inflammatory responses induce a vulnerable epithelial state with robust replication of SARS-CoV-2, which may have an impact on disease outcome and virus transmission.


Subject(s)
/etiology , Interferon-gamma/immunology , Models, Immunological , /genetics , Animals , /pathology , Cell Differentiation/immunology , Colon/immunology , Colon/pathology , Colon/virology , Disease Susceptibility , Enterocytes/metabolism , Enterocytes/pathology , Enterocytes/virology , Gene Expression , Host Microbial Interactions/immunology , Humans , Interferon-gamma/administration & dosage , Intestinal Mucosa/immunology , Intestinal Mucosa/pathology , Intestinal Mucosa/virology , Mice , Organoids/immunology , Organoids/pathology , Organoids/virology , /immunology , Virus Replication/immunology
2.
Front Cell Infect Microbiol ; 10: 575559, 2020.
Article in English | MEDLINE | ID: covidwho-1000068

ABSTRACT

The current COVID-19 pandemic is a great challenge for worldwide researchers in the human microbiota area because the mechanisms and long-term effects of the infection at the GI level are not yet deeply understood. In the current review, scientific literature including original research articles, clinical studies, epidemiological reports, and review-type articles concerning human intestinal infection with SARS-CoV-2 and the possible consequences on the microbiota were reviewed. Moreover, the following aspects pertaining to COVID-19 have also been discussed: transmission, resistance in the human body, the impact of nutritional status in relation to the intestinal microbiota, and the impact of comorbid metabolic disorders such as inflammatory bowel disease (IBS), obesity, and type two diabetes (T2D). The articles investigated show that health, age, and nutritional status are associated with specific communities of bacterial species in the gut, which could influence the clinical course of COVID-19 infection. Fecal microbiota alterations were associated with fecal concentrations of SARS-CoV-2 and COVID-19 severity. Patients suffering from metabolic and gastrointestinal (GI) disorders are thought to be at a moderate-to-high risk of infection with SARS-CoV-2, indicating the direct implication of gut dysbiosis in COVID-19 severity. However, additional efforts are required to identify the initial GI symptoms of COVID-19 for possible early intervention.


Subject(s)
/microbiology , Dysbiosis/etiology , Gastrointestinal Microbiome , Pandemics , /physiology , Animals , /epidemiology , Comorbidity , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/microbiology , Disease Reservoirs/virology , Enterocytes/pathology , Enterocytes/virology , Feces/microbiology , Feces/virology , Gastrointestinal Diseases/etiology , Gastrointestinal Diseases/microbiology , Humans , Irritable Bowel Syndrome/epidemiology , Irritable Bowel Syndrome/microbiology , Metabolic Syndrome/epidemiology , Metabolic Syndrome/microbiology , Obesity/epidemiology , Obesity/microbiology , Risk Factors , /pathogenicity
3.
Virology ; 552: 43-51, 2021 01 02.
Article in English | MEDLINE | ID: covidwho-843443

ABSTRACT

This study focused on intestinal restitution including phenotype switching of absorptive enterocytes and the abundance of different enterocyte subtypes in weaned pigs after porcine epidemic diarrhea virus (PEDV) infection. At 10 days post-PEDV-inoculation, the ratio of villus height to crypt depth in both jejunum and ileum had restored, and the PEDV antigen was not detectable. However, enterocytes at the villus tips revealed epithelial-mesenchymal transition (EMT) in the jejunum in which E-cadherin expression decreased while expression of N-cadherin, vimentin, and Snail increased. Additionally, there was reduced expression of actin in microvilli and Zonula occludens-1 (ZO-1) in tight junctions. Moreover, the protein concentration of transforming growth factor ß1 (TGFß1), which mediates EMT and cytoskeleton alteration, was increased. We also found a decreased number of Peyer's patch M cells in the ileum. These results reveal incomplete restitution of enterocytes in the jejunum and potentially impaired immune surveillance in the ileum after PEDV infection.


Subject(s)
Coronavirus Infections/veterinary , Enterocytes/pathology , Epithelial-Mesenchymal Transition , Gastroenteritis, Transmissible, of Swine/pathology , Peyer's Patches/pathology , Porcine epidemic diarrhea virus/pathogenicity , Animals , Cadherins/metabolism , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Coronavirus Infections/virology , Gastroenteritis, Transmissible, of Swine/immunology , Gastroenteritis, Transmissible, of Swine/virology , Ileum/immunology , Ileum/pathology , Intestinal Mucosa/pathology , Jejunum/immunology , Jejunum/pathology , Microvilli/pathology , Swine , Tight Junctions/pathology , Transforming Growth Factor beta1/metabolism , Weaning
4.
Nat Med ; 26(7): 1077-1083, 2020 07.
Article in English | MEDLINE | ID: covidwho-260261

ABSTRACT

A novel coronavirus-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-emerged in humans in Wuhan, China, in December 2019 and has since disseminated globally1,2. As of April 16, 2020, the confirmed case count of coronavirus disease 2019 (COVID-19) had surpassed 2 million. Based on full-genome sequence analysis, SARS-CoV-2 shows high homology to SARS-related coronaviruses identified in horseshoe bats1,2. Here we show the establishment and characterization of expandable intestinal organoids derived from horseshoe bats of the Rhinolophus sinicus species that can recapitulate bat intestinal epithelium. These bat enteroids are fully susceptible to SARS-CoV-2 infection and sustain robust viral replication. Development of gastrointestinal symptoms in some patients with COVID-19 and detection of viral RNA in fecal specimens suggest that SARS-CoV-2 might cause enteric, in addition to respiratory, infection3,4. Here we demonstrate active replication of SARS-CoV-2 in human intestinal organoids and isolation of infectious virus from the stool specimen of a patient with diarrheal COVID-19. Collectively, we established the first expandable organoid culture system of bat intestinal epithelium and present evidence that SARS-CoV-2 can infect bat intestinal cells. The robust SARS-CoV-2 replication in human intestinal organoids suggests that the human intestinal tract might be a transmission route of SARS-CoV-2.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/pathology , Coronavirus Infections/transmission , Intestines/virology , Organoids/virology , Pneumonia, Viral/pathology , Pneumonia, Viral/transmission , Animals , Cell Differentiation , Cells, Cultured , Child, Preschool , Chiroptera/virology , Chlorocebus aethiops , Coronavirus Infections/virology , Enterocytes/pathology , Enterocytes/physiology , Enterocytes/virology , Female , Humans , Infant , Intestinal Mucosa/pathology , Intestinal Mucosa/virology , Intestines/pathology , Male , Organoids/pathology , Pandemics , Pneumonia, Viral/virology , Reverse Transcriptase Polymerase Chain Reaction , Vero Cells , Viral Load/genetics , Viral Load/methods , Viral Tropism/physiology
5.
Sci Immunol ; 5(47)2020 05 13.
Article in English | MEDLINE | ID: covidwho-260039

ABSTRACT

Gastrointestinal symptoms and fecal shedding of SARS-CoV-2 RNA are frequently observed in COVID-19 patients. However, it is unclear whether SARS-CoV-2 replicates in the human intestine and contributes to possible fecal-oral transmission. Here, we report productive infection of SARS-CoV-2 in ACE2+ mature enterocytes in human small intestinal enteroids. Expression of two mucosa-specific serine proteases, TMPRSS2 and TMPRSS4, facilitated SARS-CoV-2 spike fusogenic activity and promoted virus entry into host cells. We also demonstrate that viruses released into the intestinal lumen were inactivated by simulated human colonic fluid, and infectious virus was not recovered from the stool specimens of COVID-19 patients. Our results highlight the intestine as a potential site of SARS-CoV-2 replication, which may contribute to local and systemic illness and overall disease progression.


Subject(s)
Betacoronavirus/physiology , Enterocytes/virology , Membrane Proteins/metabolism , Serine Endopeptidases/metabolism , Virus Internalization , Animals , Cell Line , Duodenum/cytology , Enterocytes/pathology , Humans , Mice , Organoids/virology , Peptidyl-Dipeptidase A/metabolism , Rotavirus/physiology , Vesiculovirus/genetics
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