Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1175175 (SARS)
 19,188 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During several months of 2002, severe acute respiratory syndrome (SARS) caused by SARS-coronavirus (SARS-CoV) spread rapidly from China throughout the world causing more than 800 deaths due to the development of acute respiratory distress syndrome (ARDS). Interestingly, a novel homologue of angiotensin converting-enzyme (ACE), termed angiotensin converting enzyme 2 (ACE2) has been identified as a receptor for SARS-CoV. ACE and ACE2 share homology in their catalytic domain and provide different key functions in the renin-angiotensin system. ACE cleaves angiotensin I to generate angiotensin II that is a key effector peptide of the system and exerts multiple biological functions, whereas ACE2 reduces angiotensin II levels and thus is a negative regulator of the system. Importantly, our recent studies using ACE2 knockout mice have demonstrated that ACE2 protects murine lungs from ARDS. Furthermore, SARS-CoV infections and the Spike protein of the SARS-CoV reduce ACE2 expression. Notably, injection of SARS-CoV Spike into mice worsens acute lung failure in vivo that can be attenuated by blocking the renin-angiotensin pathway, suggesting the activation of pulmonary RAS influences the pathogenesis of ARDS and SARS.
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PMID:[Lessons from SARS: a new potential therapy for acute respiratory distress syndrome (ARDS) with angiotensin converting enzyme 2 (ACE2)]. 1834 Sep 98

Human coronavirus NL63 (NL63), a member of the group I coronaviruses, may cause acute respiratory diseases in young children and immunocompromised adults. Like severe acute respiratory syndrome coronavirus (SARS-CoV), NL63 also employs the human angiotensin-converting enzyme 2 (hACE2) receptor for cellular entry. To identify residues in the spike protein of NL63 that are important for hACE2 binding, this study first generated a series of S1-truncated variants, examined their associations with the hACE2 receptor and subsequently mapped a minimal receptor-binding domain (RBD) that consisted of 141 residues (aa 476-616) towards the C terminus of the S1 domain. The data also demonstrated that the NL63 RBD bound to hACE2 more efficiently than its full-length counterpart and had a binding efficiency comparable to the S1 or RBD of SARS-CoV. A further series of RBD variants was generated using site-directed mutagenesis and random mutant library screening assays, and identified 15 residues (C497, Y498, V499, C500, K501, R518, R530, V531, G534, G537, D538, S540, E582, W585 and T591) that appeared to be critical for the RBD-hACE2 association. These critical residues clustered in three separate regions (designated RI, RII and RIII) inside the RBD, which may represent three receptor-binding sites. These results may help to delineate the molecular interactions between the S protein of NL63 and the hACE2 receptor, and may also enhance our understanding of the pathogenesis of NL63 and SARS-CoV.
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PMID:Identification of residues in the receptor-binding domain (RBD) of the spike protein of human coronavirus NL63 that are critical for the RBD-ACE2 receptor interaction. 1834 44

Severe acute respiratory syndrome (SARS) is a systemic disease characterized by both lung pathology and widespread extrapulmonary virus dissemination causing multiple organ injuries. In this regard, renal dysfunction is an ominous sign in patients with SARS. Indeed, clusters of SARS coronavirus (SARS-CoV) particles have been detected in the cytoplasm of renal tubular epithelial cells in postmortem studies, explaining the presence of infectious virus in the urine of SARS patients. In order to investigate the potential SARS-CoV kidney tropism, we have evaluated the susceptibility of human renal cells of tubular and glomerular origin to in vitro SARS-CoV infection. Immortalized cultures of differentiated proximal tubular epithelial cells (PTEC), glomerular mesangial cells (MC), and glomerular epithelial cells (podocytes) were found to express the SARS-CoV receptor angiotensin-converting enzyme 2 on their surface. Productive infection, however, occurred only in PTEC but not in glomerular cells. A transient infection with poor virus production was observed in MC, whereas podocytes were not permissive to SARS-CoV infection. In contrast to the cytopathic infection of the Vero E6 cell line, SARS-CoV did not cause overt cytopathic effects in PTEC or MC. Of interest, PTEC, but not MC, maintained stable levels of SARS-CoV production in serial subcultures, suggesting a persistent state of infection. In this regard, a SARS-CoV variant with increased replication capacity in PTEC was selected after four serial subculture passages. This SARS-CoV variant acquired a single nonconservative amino acid change from glutamic acid (E) to alanine (A) at position 11 in the viral membrane (M) protein. The E11A point mutation was sufficient for enhanced SARS-CoV replication and persistence in PTEC when introduced in a SARS-CoV recombinant infectious clone. These findings indicate that human PTEC may represent a site of SARS-CoV productive and persistent replication favoring the emergence of viral variants with increased replication capacity, at least in these kidney cells.
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PMID:Persistent replication of severe acute respiratory syndrome coronavirus in human tubular kidney cells selects for adaptive mutations in the membrane protein. 1836 28

The primary targets for SARS-CoV infection are the epithelial cells in the respiratory and intestinal tract. The angiotensin-converting enzyme 2 (ACE-2) has been identified as a functional receptor for SARS-CoV. ACE-2 has been shown to be expressed at the apical domain of polarized Calu-3 cells. In this report, interferon alfacon 1 was examined for inhibitory activities against SARS-CoV on human lung carcinoma epithelial Calu-3 cell line and the other three African green monkey kidney epithelial cell lines. Interferon alfacon 1 demonstrated significant antiviral activity in neutral red uptake assay and virus yield reduction assay. The data might provide an important insight into the mechanism of pathogenesis of SARS-CoV allowing further development of antiviral therapies for treating SARS infections.
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PMID:Interferon alfacon 1 inhibits SARS-CoV infection in human bronchial epithelial Calu-3 cells. 1840 49

It is believed that a novel coronavirus, severe acute respiratory syndrome coronavirus (SARS-CoV), was passed from palm civets to humans and caused the epidemic of SARS in 2002 to 2003. The major species barriers between humans and civets for SARS-CoV infections are the specific interactions between a defined receptor-binding domain (RBD) on a viral spike protein and its host receptor, angiotensin-converting enzyme 2 (ACE2). In this study a chimeric ACE2 bearing the critical N-terminal helix from civet and the remaining peptidase domain from human was constructed, and it was shown that this construct has the same receptor activity as civet ACE2. In addition, crystal structures of the chimeric ACE2 complexed with RBDs from various human and civet SARS-CoV strains were determined. These structures, combined with a previously determined structure of human ACE2 complexed with the RBD from a human SARS-CoV strain, have revealed a structural basis for understanding the major species barriers between humans and civets for SARS-CoV infections. They show that the major species barriers are determined by interactions between four ACE2 residues (residues 31, 35, 38, and 353) and two RBD residues (residues 479 and 487), that early civet SARS-CoV isolates were prevented from infecting human cells due to imbalanced salt bridges at the hydrophobic virus/receptor interface, and that SARS-CoV has evolved to gain sustained infectivity for human cells by eliminating unfavorable free charges at the interface through stepwise mutations at positions 479 and 487. These results enhance our understanding of host adaptations and cross-species infections of SARS-CoV and other emerging animal viruses.
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PMID:Structural analysis of major species barriers between humans and palm civets for severe acute respiratory syndrome coronavirus infections. 1844 27

During several months of 2002, severe acute respiratory syndrome (SARS) caused by SARS-coronavirus (SARS-CoV) spread rapidly from China throughout the world, causing more than 800 deaths due to the development of acute respiratory distress syndrome (ARDS), which is the severe form of acute lung injury (ALI). Interestingly, a novel homologue of angiotensin-converting enzyme, termed angiotensin-converting enzyme 2 (ACE2), has been identified as a receptor for SARS-CoV. Angiotensin-converting enzyme and ACE2 share homology in their catalytic domain and provide different key functions in the renin-angiotensin system (RAS). Angiotensin-converting enzyme cleaves angiotensin I to generate angiotensin II, which is a key effector peptide of the system and exerts multiple biological functions, whereas ACE2 reduces angiotensin II levels. Importantly, our recent studies using ACE2 knockout mice have demonstrated that ACE2 protects murine lungs from ARDS. Furthermore, SARS-CoV infections and the Spike protein of the SARS-CoV reduce ACE2 expression. Notably, injection of SARS-CoV Spike into mice worsens acute lung failure in vivo, which can be attenuated by blocking the renin-angiotensin pathway, suggesting that the activation of the pulmonary RAS influences the pathogenesis of ALI/ARDS and SARS.
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PMID:The discovery of angiotensin-converting enzyme 2 and its role in acute lung injury in mice. 1844 62

The outbreak of severe acute respiratory syndrome (SARS) in 2002-2003 has had a significant impact worldwide. No effective prophylaxis or treatment for SARS is available up to now. Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for SARS-associated coronavirus (SARS-CoV). By expressing a U6 promoter-driven small interfering RNA containing sequences homologous to part of ACE2 mRNA, we successfully silenced ACE2 expression in Vero E6 cells. By detecting negative strand SARS-CoV RNA and measuring RNA copy numbers of SARS-CoV by real-time reverse transcription polymerase chain reaction (RT-PCR), we demonstrated that SARS-CoV infection was reduced in the ACE2-silenced cell lines. These findings support the involvement of ACE2 in SARS-CoV infections and provide a basis for further studies on potential use of siRNA targeting ACE2 as a preventive or therapeutic strategy for SARS.
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PMID:siRNA silencing of angiotensin-converting enzyme 2 reduced severe acute respiratory syndrome-associated coronavirus replications in Vero E6 cells. 1844 85

Severe acute respiratory syndrome coronavirus (SARS-CoV) is a high-risk infectious pathogen. In the proposed model of respiratory failure, SARS-CoV down-regulates its receptor, angiotensin-converting enzyme 2 (ACE2), but the mechanism involved is unknown. We found that the spike protein of SARS-CoV (SARS-S) induced TNF-alpha-converting enzyme (TACE)-dependent shedding of the ACE2 ectodomain. The modulation of TACE activity by SARS-S depended on the cytoplasmic domain of ACE2, because deletion mutants of ACE2 lacking the carboxyl-terminal region did not induce ACE2 shedding or TNF-alpha production. In contrast, the spike protein of HNL63-CoV (NL63-S), a CoV that uses ACE2 as a receptor and mainly induces the common cold, caused neither of these cellular responses. Intriguingly, viral infection, judged by real-time RT-PCR analysis of SARS-CoV mRNA expression, was significantly attenuated by deletion of the cytoplasmic tail of ACE2 or knock-down of TACE expression by siRNA. These data suggest that cellular signals triggered by the interaction of SARS-CoV with ACE2 are positively involved in viral entry but lead to tissue damage. These findings may lead to the development of anti-SARS-CoV agents.
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PMID:Modulation of TNF-alpha-converting enzyme by the spike protein of SARS-CoV and ACE2 induces TNF-alpha production and facilitates viral entry. 1849 Jun 52

Infection of humans with the severe acute respiratory syndrome coronavirus (SARS-CoV) results in substantial morbidity and mortality, with death resulting primarily from respiratory failure. While the lungs are the major site of infection, the brain is also infected in some patients. Brain infection may result in long-term neurological sequelae, but little is known about the pathogenesis of SARS-CoV in this organ. We previously showed that the brain was a major target organ for infection in mice that are transgenic for the SARS-CoV receptor (human angiotensin-converting enzyme 2). Herein, we use these mice to show that virus enters the brain primarily via the olfactory bulb, and infection results in rapid, transneuronal spread to connected areas of the brain. This extensive neuronal infection is the main cause of death because intracranial inoculation with low doses of virus results in a uniformly lethal disease even though little infection is detected in the lungs. Death of the animal likely results from dysfunction and/or death of infected neurons, especially those located in cardiorespiratory centers in the medulla. Remarkably, the virus induces minimal cellular infiltration in the brain. Our results show that neurons are a highly susceptible target for SARS-CoV and that only the absence of the host cell receptor prevents severe murine brain disease.
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PMID:Severe acute respiratory syndrome coronavirus infection causes neuronal death in the absence of encephalitis in mice transgenic for human ACE2. 1849 71

Cell entry of severe acute respiratory syndrome coronavirus (SARS-CoV) is mediated by the viral spike (S) protein. Amino acids 319-510 on the S protein have been mapped as the receptor-binding domain (RBD), which mediates binding to the SARS-CoV receptor angiotensin converting enzyme 2 (ACE2) on SARS-CoV susceptible cells. In this study, we expressed a fusion protein containing the human codon-optimized RBD of the SARS-CoV spike protein linked to the Fc portion of human IgG1 (named RBD-Fc) in HEK293 cells. The RBD-Fc protein was purified by affinity chromatography. The flow cytometry assay showed that the purified RBD-Fc protein could bind to ACE2. We demonstrated that the RBD spike protein alone could be internalized into SARS-CoV susceptible cells together with ACE2. We also showed that the removal of N-glycans from the RBD spike protein did not abolish this phenomenon. Our discoveries may have some implications for the development of the SARS vaccine.
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PMID:Endocytosis of the receptor-binding domain of SARS-CoV spike protein together with virus receptor ACE2. 1855 41


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