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1.
J Am Chem Soc ; 144(9): 3761-3765, 2022 03 09.
Article in English | MEDLINE | ID: covidwho-1713117

ABSTRACT

The Covid-19 pandemic highlights the urgent need for cost-effective processes to rapidly manufacture antiviral drugs at scale. Here we report a concise biocatalytic process for Molnupiravir, a nucleoside analogue recently approved as an orally available treatment for SARS-CoV-2. Key to the success of this process was the development of an efficient biocatalyst for the production of N-hydroxy-cytidine through evolutionary adaption of the hydrolytic enzyme cytidine deaminase. This engineered biocatalyst performs >85 000 turnovers in less than 3 h, operates at 180 g/L substrate loading, and benefits from in situ crystallization of the N-hydroxy-cytidine product (85% yield), which can be converted to Molnupiravir by a selective 5'-acylation using Novozym 435.


Subject(s)
Antiviral Agents , COVID-19/drug therapy , Cytidine Deaminase/metabolism , Cytidine/analogs & derivatives , SARS-CoV-2 , Biocatalysis , Cytidine/biosynthesis , Cytidine/metabolism , Cytidine Deaminase/genetics , Escherichia coli/enzymology , Escherichia coli/genetics , Hydroxylamines , Metabolic Engineering , Protein Engineering , Uridine/metabolism
2.
Signal Transduct Target Ther ; 7(1): 7, 2022 01 04.
Article in English | MEDLINE | ID: covidwho-1606287

ABSTRACT

Activation-induced cytidine deaminase (AID) initiates class-switch recombination and somatic hypermutation (SHM) in antibody genes. Protein expression and activity are tightly controlled by various mechanisms. However, it remains unknown whether a signal from the extracellular environment directly affects the AID activity in the nucleus where it works. Here, we demonstrated that a deubiquitinase USP10, which specifically stabilizes nuclear AID protein, can translocate into the nucleus after AKT-mediated phosphorylation at its T674 within the NLS domain. Interestingly, the signals from BCR and TLR1/2 synergistically promoted this phosphorylation. The deficiency of USP10 in B cells significantly decreased AID protein levels, subsequently reducing neutralizing antibody production after immunization with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or human immunodeficiency virus type 1 (HIV-1) nanoparticle vaccines. Collectively, we demonstrated that USP10 functions as an integrator for both BCR and TLR signals and directly regulates nuclear AID activity. Its manipulation could be used for the development of vaccines and adjuvants.


Subject(s)
AIDS Vaccines/immunology , B-Cell Activating Factor/immunology , COVID-19 Vaccines/immunology , Cytidine Deaminase/immunology , HIV-1/immunology , Nanoparticles , SARS-CoV-2/immunology , Signal Transduction/immunology , Ubiquitin Thiolesterase/immunology , Ubiquitination/immunology , AIDS Vaccines/genetics , Animals , B-Cell Activating Factor/genetics , COVID-19 Vaccines/genetics , Cytidine Deaminase/genetics , HEK293 Cells , HIV-1/genetics , Humans , Mice , Mice, Knockout , SARS-CoV-2/genetics , Signal Transduction/genetics , Ubiquitin Thiolesterase/genetics
3.
Int J Med Sci ; 18(16): 3788-3793, 2021.
Article in English | MEDLINE | ID: covidwho-1512989

ABSTRACT

As the world is racing to develop perpetual immunity to the SARS-CoV-2 virus. The emergence of new viral strains, together with vaccination and reinfections, are all contributing to a long-term immunity against the deadly virus that has taken over the world since its introduction to humans in late December 2019. The discovery that more than 95 percent of people who recovered from COVID-19 had long-lasting immunity and that asymptomatic people have a different immune response to SARS-CoV-2 than symptomatic people has shifted attention to how our immune system initiates such diverse responses. These findings have provided reason to believe that SARS-CoV-2 days are numbered. Hundreds of research papers have been published on the causes of long-lasting immune responses and variations in the numbers of different immune cell types in COVID 19 survivors, but the main reason of these differences has still not been adequately identified. In this article, we focus on the activation-induced cytidine deaminase (AID), which initiates molecular processes that allow our immune system to generate antibodies against SARS-CoV-2. To establish lasting immunity to SARS-CoV-2, we suggest that AID could be the key to unlocking it.


Subject(s)
COVID-19/immunology , Cytidine Deaminase/genetics , Immunity/genetics , SARS-CoV-2/immunology , COVID-19/virology , Cytidine/genetics , Cytidine/immunology , Cytidine Deaminase/immunology , Deamination/immunology , Humans , SARS-CoV-2/pathogenicity , Vaccination
4.
Front Immunol ; 12: 690416, 2021.
Article in English | MEDLINE | ID: covidwho-1317226

ABSTRACT

The AID (activation-induced cytidine deaminase)/APOBEC (apolipoprotein B mRNA editing enzyme catalytic subunit) family with its multifaceted mode of action emerges as potent intrinsic host antiviral system that acts against a variety of DNA and RNA viruses including coronaviruses. All family members are cytosine-to-uracil deaminases that either have a profound role in driving a strong and specific humoral immune response (AID) or restricting the virus itself by a plethora of mechanisms (APOBECs). In this article, we highlight some of the key aspects apparently linking the AID/APOBECs and SARS-CoV-2. Among those is our discovery that APOBEC4 shows high expression in cell types and anatomical parts targeted by SARS-CoV-2. Additional focus is given by us to the lymphoid structures and AID as the master regulator of germinal center reactions, which result in antibody production by plasma and memory B cells. We propose the dissection of the AID/APOBECs gene signature towards decisive determinants of the patient-specific and/or the patient group-specific antiviral response. Finally, the patient-specific mapping of the AID/APOBEC polymorphisms should be considered in the light of COVID-19.


Subject(s)
APOBEC-1 Deaminase/genetics , COVID-19/enzymology , COVID-19/immunology , Cytidine Deaminase/genetics , SARS-CoV-2/genetics , Transcriptome , Antibodies, Viral/immunology , B-Lymphocytes/immunology , COVID-19/virology , Germinal Center/immunology , Host Microbial Interactions/genetics , Host Microbial Interactions/immunology , Humans , Immunity, Humoral/genetics , Plasma Cells/immunology , Polymorphism, Genetic , RNA Editing/genetics , RNA, Viral/genetics
5.
Sci Rep ; 11(1): 13971, 2021 07 07.
Article in English | MEDLINE | ID: covidwho-1301179

ABSTRACT

To unravel the source of SARS-CoV-2 introduction and the pattern of its spreading and evolution in the United Arab Emirates, we conducted meta-transcriptome sequencing of 1067 nasopharyngeal swab samples collected between May 9th and Jun 29th, 2020 during the first peak of the local COVID-19 epidemic. We identified global clade distribution and eleven novel genetic variants that were almost absent in the rest of the world and that defined five subclades specific to the UAE viral population. Cross-settlement human-to-human transmission was related to the local business activity. Perhaps surprisingly, at least 5% of the population were co-infected by SARS-CoV-2 of multiple clades within the same host. We also discovered an enrichment of cytosine-to-uracil mutation among the viral population collected from the nasopharynx, that is different from the adenosine-to-inosine change previously reported in the bronchoalveolar lavage fluid samples and a previously unidentified upregulation of APOBEC4 expression in nasopharynx among infected patients, indicating the innate immune host response mediated by ADAR and APOBEC gene families could be tissue-specific. The genomic epidemiological and molecular biological knowledge reported here provides new insights for the SARS-CoV-2 evolution and transmission and points out future direction on host-pathogen interaction investigation.


Subject(s)
COVID-19/epidemiology , COVID-19/immunology , Coinfection/epidemiology , Genomics , Immunity, Innate , Mutation , SARS-CoV-2/genetics , Adult , COVID-19/transmission , Cytidine Deaminase/genetics , Female , Gene Expression Profiling , Genome, Viral/genetics , Humans , Male , Middle Aged , Nasopharynx/virology , Organ Specificity , SARS-CoV-2/immunology
6.
PLoS One ; 15(12): e0244025, 2020.
Article in English | MEDLINE | ID: covidwho-992706

ABSTRACT

Coronaviruses such as SARS-CoV-2 regularly infect host tissues that express antiviral proteins (AVPs) in abundance. Understanding how they evolve to adapt or evade host immune responses is important in the effort to control the spread of infection. Two AVPs that may shape viral genomes are the zinc finger antiviral protein (ZAP) and the apolipoprotein B mRNA editing enzyme-catalytic polypeptide-like 3 (APOBEC3). The former binds to CpG dinucleotides to facilitate the degradation of viral transcripts while the latter frequently deaminates C into U residues which could generate notable viral sequence variations. We tested the hypothesis that both APOBEC3 and ZAP impose selective pressures that shape the genome of an infecting coronavirus. Our investigation considered a comprehensive number of publicly available genomes for seven coronaviruses (SARS-CoV-2, SARS-CoV, and MERS infecting Homo sapiens, Bovine CoV infecting Bos taurus, MHV infecting Mus musculus, HEV infecting Sus scrofa, and CRCoV infecting Canis lupus familiaris). We show that coronaviruses that regularly infect tissues with abundant AVPs have CpG-deficient and U-rich genomes; whereas those that do not infect tissues with abundant AVPs do not share these sequence hallmarks. Among the coronaviruses surveyed herein, CpG is most deficient in SARS-CoV-2 and a temporal analysis showed a marked increase in C to U mutations over four months of SARS-CoV-2 genome evolution. Furthermore, the preferred motifs in which these C to U mutations occur are the same as those subjected to APOBEC3 editing in HIV-1. These results suggest that both ZAP and APOBEC3 shape the SARS-CoV-2 genome: ZAP imposes a strong CpG avoidance, and APOBEC3 constantly edits C to U. Evolutionary pressures exerted by host immune systems onto viral genomes may motivate novel strategies for SARS-CoV-2 vaccine development.


Subject(s)
COVID-19/genetics , Coronavirus/genetics , Cytidine Deaminase/genetics , RNA-Binding Proteins/genetics , Repressor Proteins/genetics , APOBEC Deaminases , Animals , COVID-19/pathology , COVID-19/virology , Cattle , Coronavirus/classification , Coronavirus/pathogenicity , Dogs , Evolution, Molecular , Genome, Viral/genetics , Humans , Mice , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/pathogenicity , SARS Virus/genetics , SARS Virus/pathogenicity , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Swine/virology
7.
Ocul Immunol Inflamm ; 28(5): 735-738, 2020 Jul 03.
Article in English | MEDLINE | ID: covidwho-616708

ABSTRACT

PURPOSE: The spike proteins of SARS-CoV-2 interact with ACE2 or basigin/CD147 receptors, regulating human-to-human transmissions of COVID-19 together with serine protease TMPRSS2. The expression of these receptors on the ocular surface is unknown. MATERIAL AND METHODS: Gene expression of SARS-CoV-2 receptors was investigated in conjunctival epithelial cell samples and in ex-vivo cornea samples using microarray or transcriptome sequencing. RESULTS: ACE2 is expressed in conjunctival samples at a low level, while BSG and TMPRSS2 are expressed at intermediate levels in both conjunctiva and cornea. Other receptors such as ANPEP, AGTR2 are expressed at low level in the conjunctiva. Two RNA editing enzymes involved in antiviral responses, APOBEC3A, and ADAR-1 were also highly expressed. CONCLUSIONS: The ocular surface may represent an entry point for the SARS-CoV-2 in the human body. The conjunctiva and the cornea can adopt antiviral countermeasures which may explain the low prevalence of eye involvement.


Subject(s)
Betacoronavirus/physiology , Conjunctiva/metabolism , Cornea/metabolism , Coronavirus Infections/metabolism , Gene Expression Regulation/physiology , Pneumonia, Viral/metabolism , Receptors, Virus/genetics , Adenosine Deaminase/genetics , Adolescent , Adult , Aged , Angiotensin-Converting Enzyme 2 , Basigin/genetics , COVID-19 , Child , Cytidine Deaminase/genetics , Gene Expression Profiling , Humans , Middle Aged , Pandemics , Peptidyl-Dipeptidase A/genetics , Proteins/genetics , RNA-Binding Proteins/genetics , SARS-CoV-2 , Serine Endopeptidases/genetics , Young Adult
8.
mSphere ; 5(3)2020 06 24.
Article in English | MEDLINE | ID: covidwho-612518

ABSTRACT

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has motivated an intensive analysis of its molecular epidemiology following its worldwide spread. To understand the early evolutionary events following its emergence, a data set of 985 complete SARS-CoV-2 sequences was assembled. Variants showed a mean of 5.5 to 9.5 nucleotide differences from each other, consistent with a midrange coronavirus substitution rate of 3 × 10-4 substitutions/site/year. Almost one-half of sequence changes were C→U transitions, with an 8-fold base frequency normalized directional asymmetry between C→U and U→C substitutions. Elevated ratios were observed in other recently emerged coronaviruses (SARS-CoV, Middle East respiratory syndrome [MERS]-CoV), and decreasing ratios were observed in other human coronaviruses (HCoV-NL63, -OC43, -229E, and -HKU1) proportionate to their increasing divergence. C→U transitions underpinned almost one-half of the amino acid differences between SARS-CoV-2 variants and occurred preferentially in both 5' U/A and 3' U/A flanking sequence contexts comparable to favored motifs of human APOBEC3 proteins. Marked base asymmetries observed in nonpandemic human coronaviruses (U ≫ A > G ≫ C) and low G+C contents may represent long-term effects of prolonged C→U hypermutation in their hosts. The evidence that much of sequence change in SARS-CoV-2 and other coronaviruses may be driven by a host APOBEC-like editing process has profound implications for understanding their short- and long-term evolution. Repeated cycles of mutation and reversion in favored mutational hot spots and the widespread occurrence of amino acid changes with no adaptive value for the virus represent a quite different paradigm of virus sequence change from neutral and Darwinian evolutionary frameworks and are not incorporated by standard models used in molecular epidemiology investigations.IMPORTANCE The wealth of accurately curated sequence data for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), its long genome, and its low substitution rate provides a relatively blank canvas with which to investigate effects of mutational and editing processes imposed by the host cell. The finding that a large proportion of sequence change in SARS-CoV-2 in the initial months of the pandemic comprised C→U mutations in a host APOBEC-like context provides evidence for a potent host-driven antiviral editing mechanism against coronaviruses more often associated with antiretroviral defense. In evolutionary terms, the contribution of biased, convergent, and context-dependent mutations to sequence change in SARS-CoV-2 is substantial, and these processes are not incorporated by standard models used in molecular epidemiology investigations.


Subject(s)
Betacoronavirus/genetics , Cytosine/analysis , Genome, Viral/genetics , Polymorphism, Single Nucleotide/genetics , Uracil/analysis , APOBEC Deaminases , Base Composition/genetics , Base Sequence/genetics , COVID-19 , Coronavirus Infections/pathology , Cytidine Deaminase/genetics , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Pandemics , Pneumonia, Viral/pathology , SARS Virus/genetics , SARS-CoV-2
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