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Genet Med ; 24(8): 1653-1663, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1819495


PURPOSE: Emerging evidence suggest that infection-dependent hyperactivation of complement system (CS) may worsen COVID-19 outcome. We investigated the role of predicted high impact rare variants - referred as qualifying variants (QVs) - of CS genes in predisposing asymptomatic COVID-19 in elderly individuals, known to be more susceptible to severe disease. METHODS: Exploiting exome sequencing data and 56 CS genes, we performed a gene-based collapsing test between 164 asymptomatic subjects (aged ≥60 years) and 56,885 European individuals from the Genome Aggregation Database. We replicated this test comparing the same asymptomatic individuals with 147 hospitalized patients with COVID-19. RESULTS: We found an enrichment of QVs in 3 genes (MASP1, COLEC11, and COLEC10), which belong to the lectin pathway, in the asymptomatic cohort. Analyses of complement activity in serum showed decreased activity of lectin pathway in asymptomatic individuals with QVs. Finally, we found allelic variants associated with asymptomatic COVID-19 phenotype and with a decreased expression of MASP1, COLEC11, and COLEC10 in lung tissue. CONCLUSION: This study suggests that genetic rare variants can protect from severe COVID-19 by mitigating the activity of lectin pathway and prothrombin. The genetic data obtained through ES of 786 asymptomatic and 147 hospitalized individuals are publicly available at

COVID-19 , Aged , COVID-19/genetics , Collectins/genetics , Collectins/metabolism , Germ Cells , Humans , Lectins/genetics , SARS-CoV-2 , Whole Exome Sequencing
Int J Mol Sci ; 23(8)2022 Apr 09.
Article in English | MEDLINE | ID: covidwho-1785747


Tracing the appearance and evolution of virus variants is essential in the management of the COVID-19 pandemic. Here, we focus on SARS-CoV-2 spread in Italian patients by using viral sequences deposited in public databases and a tracing procedure which is used to monitor the evolution of the pandemic and detect the spreading, within the infected population of emergent sub-clades with a potential positive selection. Analyses of a collection of monthly samples focused on Italy highlighted the appearance and evolution of all the main viral sub-trees emerging at the end of the first year of the pandemic. It also identified additional expanding subpopulations which spread during the second year (i.e., 2021). Three-dimensional (3D) modelling of the main amino acid changes in mutated viral proteins, including ORF1ab (nsp3, nsp4, 2'-o-ribose methyltransferase, nsp6, helicase, nsp12 [RdRp]), N, ORF3a, ORF8, and spike proteins, shows the potential of the analysed structural variations to result in epistatic modulation and positive/negative selection pressure. These analyzes will be of importance to the early identification of emerging clades, which can develop into new "variants of concern" (i.e., VOC). These analyses and settings will also help SARS-CoV-2 coronet genomic centers in other countries to trace emerging worldwide variants.

COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , Humans , Mutation , Pandemics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/metabolism
Int J Mol Sci ; 23(4)2022 Feb 09.
Article in English | MEDLINE | ID: covidwho-1690219


The development of prophylactic agents against the SARS-CoV-2 virus is a public health priority in the search for new surrogate markers of active virus replication. Early detection markers are needed to follow disease progression and foresee patient negativization. Subgenomic RNA transcripts (with a focus on sgN) were evaluated in oro/nasopharyngeal swabs from COVID-19-affected patients with an analysis of 315 positive samples using qPCR technology. Cut-off Cq values for sgN (Cq < 33.15) and sgE (Cq < 34.06) showed correlations to high viral loads. The specific loss of sgN in home-isolated and hospitalized COVID-19-positive patients indicated negativization of patient condition, 3-7 days from the first swab, respectively. A new detection kit for sgN, gene E, gene ORF1ab, and gene RNAse P was developed recently. In addition, in vitro studies have shown that 2'-O-methyl antisense RNA (related to the sgN sequence) can impair SARS-CoV-2 N protein synthesis, viral replication, and syncytia formation in human cells (i.e., HEK-293T cells overexpressing ACE2) upon infection with VOC Alpha (B.1.1.7)-SARS-CoV-2 variant, defining the use that this procedure might have for future therapeutic actions against SARS-CoV-2.

COVID-19/virology , Coronavirus Nucleocapsid Proteins/genetics , SARS-CoV-2/physiology , Virus Replication/physiology , Coronavirus Nucleocapsid Proteins/analysis , Giant Cells/drug effects , Giant Cells/virology , HEK293 Cells , Humans , Limit of Detection , Nasopharynx/virology , Phosphoproteins/analysis , Phosphoproteins/genetics , RNA, Antisense/pharmacology , RNA, Viral , Ribonuclease P/genetics , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , Sensitivity and Specificity , Social Isolation , Viral Load , Viroporin Proteins/genetics , Virus Replication/drug effects
Sci Signal ; 14(690)2021 07 06.
Article in English | MEDLINE | ID: covidwho-1299215


Inorganic polyphosphates (polyPs) are linear polymers composed of repeated phosphate (PO4 3-) units linked together by multiple high-energy phosphoanhydride bonds. In addition to being a source of energy, polyPs have cytoprotective and antiviral activities. Here, we investigated the antiviral activities of long-chain polyPs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In molecular docking analyses, polyPs interacted with several conserved amino acid residues in angiotensin-converting enzyme 2 (ACE2), the host receptor that facilitates virus entry, and in viral RNA-dependent RNA polymerase (RdRp). ELISA and limited proteolysis assays using nano- LC-MS/MS mapped polyP120 binding to ACE2, and site-directed mutagenesis confirmed interactions between ACE2 and SARS-CoV-2 RdRp and identified the specific amino acid residues involved. PolyP120 enhanced the proteasomal degradation of both ACE2 and RdRp, thus impairing replication of the British B.1.1.7 SARS-CoV-2 variant. We thus tested polyPs for functional interactions with the virus in SARS-CoV-2-infected Vero E6 and Caco2 cells and in primary human nasal epithelial cells. Delivery of a nebulized form of polyP120 reduced the amounts of viral positive-sense genomic and subgenomic RNAs, of RNA transcripts encoding proinflammatory cytokines, and of viral structural proteins, thereby presenting SARS-CoV-2 infection in cells in vitro.

Antiviral Agents/pharmacology , COVID-19/drug therapy , Polyphosphates/pharmacology , SARS-CoV-2/drug effects , Administration, Inhalation , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/chemistry , COVID-19/metabolism , COVID-19/virology , Caco-2 Cells , Chlorocebus aethiops , Coronavirus RNA-Dependent RNA Polymerase/chemistry , Coronavirus RNA-Dependent RNA Polymerase/genetics , Coronavirus RNA-Dependent RNA Polymerase/metabolism , Cytokines/metabolism , HEK293 Cells , Host Microbial Interactions/drug effects , Host Microbial Interactions/genetics , Host Microbial Interactions/physiology , Humans , In Vitro Techniques , Models, Biological , Molecular Docking Simulation , Nebulizers and Vaporizers , Polyphosphates/administration & dosage , Polyphosphates/chemistry , Proteasome Endopeptidase Complex/metabolism , Protein Interaction Domains and Motifs , Proteolysis/drug effects , RNA, Viral/genetics , RNA, Viral/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/physiology , Sequence Homology, Amino Acid , Signal Transduction/drug effects , Vero Cells , Virus Replication/drug effects