ABSTRACT
The bat sarbecovirus RaTG13 is a close relative of SARS-CoV-2, the cause of the COVID-19 pandemic. However, this bat virus was most likely unable to directly infect humans since its Spike (S) protein does not interact efficiently with the human ACE2 receptor. Here, we show that a single T403R mutation increases binding of RaTG13 S to human ACE2 and allows VSV pseudoparticle infection of human lung cells and intestinal organoids. Conversely, mutation of R403T in the SARS-CoV-2 S reduces pseudoparticle infection and viral replication. The T403R RaTG13 S is neutralized by sera from individuals vaccinated against COVID-19 indicating that vaccination might protect against future zoonoses. Our data suggest that a positively charged amino acid at position 403 in the S protein is critical for efficient utilization of human ACE2 by S proteins of bat coronaviruses. This finding could help to better predict the zoonotic potential of animal coronaviruses.
Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Protein Binding , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Animals , COVID-19/virology , COVID-19 Vaccines , Caco-2 Cells , Cloning, Molecular , HEK293 Cells , Humans , Molecular Dynamics Simulation , Mutation , Replicon , Species Specificity , Stem Cells , ZoonosesABSTRACT
Interferon-induced transmembrane proteins (IFITMs 1, 2 and 3) can restrict viral pathogens, but pro- and anti-viral activities have been reported for coronaviruses. Here, we show that artificial overexpression of IFITMs blocks SARS-CoV-2 infection. However, endogenous IFITM expression supports efficient infection of SARS-CoV-2 in human lung cells. Our results indicate that the SARS-CoV-2 Spike protein interacts with IFITMs and hijacks them for efficient viral infection. IFITM proteins were expressed and further induced by interferons in human lung, gut, heart and brain cells. IFITM-derived peptides and targeting antibodies inhibit SARS-CoV-2 entry and replication in human lung cells, cardiomyocytes and gut organoids. Our results show that IFITM proteins are cofactors for efficient SARS-CoV-2 infection of human cell types representing in vivo targets for viral transmission, dissemination and pathogenesis and are potential targets for therapeutic approaches.
Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Antigens, Differentiation/genetics , Membrane Proteins/genetics , RNA-Binding Proteins/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Neutralizing/pharmacology , Antigens, Differentiation/metabolism , Binding Sites , COVID-19/virology , Gene Expression Regulation , Host-Pathogen Interactions/drug effects , Host-Pathogen Interactions/genetics , Humans , Interferon-beta/pharmacology , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/metabolism , Protein Binding , Protein Interaction Domains and Motifs , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , RNA-Binding Proteins/antagonists & inhibitors , RNA-Binding Proteins/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , Sequence Alignment , Sequence Homology, Amino Acid , Spike Glycoprotein, Coronavirus/metabolism , Virus Attachment/drug effectsABSTRACT
Infection-related diabetes can arise as a result of virus-associated ß-cell destruction. Clinical data suggest that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing the coronavirus disease 2019 (COVID-19), impairs glucose homoeostasis, but experimental evidence that SARS-CoV-2 can infect pancreatic tissue has been lacking. In the present study, we show that SARS-CoV-2 infects cells of the human exocrine and endocrine pancreas ex vivo and in vivo. We demonstrate that human ß-cells express viral entry proteins, and SARS-CoV-2 infects and replicates in cultured human islets. Infection is associated with morphological, transcriptional and functional changes, including reduced numbers of insulin-secretory granules in ß-cells and impaired glucose-stimulated insulin secretion. In COVID-19 full-body postmortem examinations, we detected SARS-CoV-2 nucleocapsid protein in pancreatic exocrine cells, and in cells that stain positive for the ß-cell marker NKX6.1 and are in close proximity to the islets of Langerhans in all four patients investigated. Our data identify the human pancreas as a target of SARS-CoV-2 infection and suggest that ß-cell infection could contribute to the metabolic dysregulation observed in patients with COVID-19.
Subject(s)
Islets of Langerhans/virology , SARS-CoV-2/growth & development , Aged , Aged, 80 and over , Angiotensin-Converting Enzyme 2/biosynthesis , Angiotensin-Converting Enzyme 2/genetics , COVID-19/physiopathology , Cells, Cultured , Diabetes Mellitus , Female , Humans , Islets of Langerhans/cytology , Islets of Langerhans/physiopathology , Male , Pancreas, Exocrine/cytology , Pancreas, Exocrine/physiopathology , Pancreas, Exocrine/virology , Pancreatic Diseases/etiology , Pancreatic Diseases/virology , Serine Endopeptidases/biosynthesis , Serine Endopeptidases/genetics , Virus Internalization , Virus ReplicationABSTRACT
BACKGROUND AND AIMS: The COVID-19 pandemic has spread worldwide and poses a severe health risk. While most patients present mild symptoms, descending pneumonia can lead to severe respiratory insufficiency. Up to 50% of patients show gastrointestinal symptoms like diarrhea or nausea, intriguingly associating with prolonged symptoms and increased severity. Thus, models to understand and validate drug efficiency in the gut of COVID-19 patients are of urgent need. METHODS: Human intestinal organoids derived from pluripotent stem cells (PSC-HIOs) have led, due to their complexity in mimicking human intestinal architecture, to an unprecedented number of successful disease models including gastrointestinal infections. Here, we employed PSC-HIOs to dissect SARS-CoV-2 pathogenesis and its inhibition by remdesivir, one of the leading drugs investigated for treatment of COVID-19. RESULTS: Immunostaining for viral entry receptor ACE2 and SARS-CoV-2 spike protein priming protease TMPRSS2 showed broad expression in the gastrointestinal tract with highest levels in the intestine, the latter faithfully recapitulated by PSC-HIOs. Organoids could be readily infected with SARS-CoV-2 followed by viral spread across entire PSC-HIOs, subsequently leading to organoid deterioration. However, SARS-CoV-2 spared goblet cells lacking ACE2 expression. Importantly, we challenged PSC-HIOs for drug testing capacity. Specifically, remdesivir effectively inhibited SARS-CoV-2 infection dose-dependently at low micromolar concentration and rescued PSC-HIO morphology. CONCLUSIONS: Thus, PSC-HIOs are a valuable tool to study SARS-CoV-2 infection and to identify and validate drugs especially with potential action in the gut.
Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19 Drug Treatment , COVID-19/metabolism , Human Embryonic Stem Cells , Intestinal Mucosa , Organoids , SARS-CoV-2/physiology , Virus Replication/drug effects , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , Caco-2 Cells , Human Embryonic Stem Cells/metabolism , Human Embryonic Stem Cells/pathology , Human Embryonic Stem Cells/virology , Humans , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Intestinal Mucosa/virology , Organoids/metabolism , Organoids/pathology , Organoids/virologyABSTRACT
Pandemic SARS-CoV-2 infection has rapidly developed into a socioeconomic and humanitarian catastrophe. Basic principles to prevent SARS-CoV-2 transmission are social distancing, face masks, contact tracing and early detection of SARS-CoV-2. To meet these requirements, virtually unlimited test capacities delivering results in a rapid and reliable manner are a prerequisite. Here, we provide and validate such a rapid, convenient and efficient kit-independent detection of SARS-CoV-2 RNA, termed COVID-quick-DET. This straightforward method operates with simple proteinase K treatment and repetitive heating steps with a sensitivity of 94.6% in head-to-head comparisons with kit-based isolation methods. This result is supported by data obtained from serially diluted SARS-CoV-2 virus stocks. Given its cost- and time-effective operation, COVID-quick-DET might be best suited for countries with general shortage or temporary acute scarcity of resources and equipment.