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1.
J Virol ; 95(12)2021 05 24.
Article in English | MEDLINE | ID: covidwho-1501541

ABSTRACT

Long disregarded as junk DNA or genomic dark matter, endogenous retroviruses (ERVs) have turned out to represent important components of the antiviral immune response. These remnants of once-infectious retroviruses not only regulate cellular immune activation, but may even directly target invading viral pathogens. In this Gem, we summarize mechanisms by which retroviral fossils protect us from viral infections. One focus will be on recent advances in the role of ERVs as regulators of antiviral gene expression.


Subject(s)
Endogenous Retroviruses/physiology , Retroelements , Virus Diseases/immunology , Animals , Endogenous Retroviruses/genetics , Enhancer Elements, Genetic , Gene Expression Regulation , Humans , Immunity, Cellular , Promoter Regions, Genetic , RNA, Double-Stranded/genetics , RNA, Double-Stranded/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , RNA, Viral/genetics , RNA, Viral/metabolism , Receptors, Pattern Recognition/metabolism , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/metabolism , Viral Proteins/metabolism , Virion/metabolism , Virus Diseases/genetics , Virus Diseases/virology
2.
J Virol ; 95(13): e0019221, 2021 06 10.
Article in English | MEDLINE | ID: covidwho-1486499

ABSTRACT

Understanding factors that affect the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is central to combatting coronavirus disease 2019 (COVID-19). The virus surface spike protein of SARS-CoV-2 mediates viral entry into cells by binding to the ACE2 receptor on epithelial cells and promoting fusion. We found that Epstein-Barr virus (EBV) induces ACE2 expression when it enters the lytic replicative cycle in epithelial cells. By using vesicular stomatitis virus (VSV) particles pseudotyped with the SARS-CoV-2 spike protein, we showed that lytic EBV replication enhances ACE2-dependent SARS-CoV-2 pseudovirus entry. We found that the ACE2 promoter contains response elements for Zta, an EBV transcriptional activator that is essential for EBV entry into the lytic cycle of replication. Zta preferentially acts on methylated promoters, allowing it to reactivate epigenetically silenced EBV promoters from latency. By using promoter assays, we showed that Zta directly activates methylated ACE2 promoters. Infection of normal oral keratinocytes with EBV leads to lytic replication in some of the infected cells, induces ACE2 expression, and enhances SARS-CoV-2 pseudovirus entry. These data suggest that subclinical EBV replication and lytic gene expression in epithelial cells, which is ubiquitous in the human population, may enhance the efficiency and extent of SARS-CoV-2 infection of epithelial cells by transcriptionally activating ACE2 and increasing its cell surface expression. IMPORTANCE SARS-CoV-2, the coronavirus responsible for COVID-19, has caused a pandemic leading to millions of infections and deaths worldwide. Identifying the factors governing susceptibility to SARS-CoV-2 is important in order to develop strategies to prevent SARS-CoV-2 infection. We show that Epstein-Barr virus, which infects and persists in >90% of adult humans, increases susceptibility of epithelial cells to infection by SARS-CoV-2. EBV, when it reactivates from latency or infects epithelial cells, increases expression of ACE2, the cellular receptor for SARS-CoV-2, enhancing infection by SARS-CoV-2. Inhibiting EBV replication with antivirals may therefore decrease susceptibility to SARS-CoV-2 infection.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Epithelial Cells/virology , Herpesvirus 4, Human/physiology , SARS-CoV-2/physiology , Virus Internalization , Virus Replication , Angiotensin-Converting Enzyme 2/metabolism , Cell Line , DNA Methylation , Epithelial Cells/metabolism , Gene Expression Regulation , Humans , Promoter Regions, Genetic , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Trans-Activators/metabolism , Virus Activation
3.
J Exp Med ; 218(9)2021 09 06.
Article in English | MEDLINE | ID: covidwho-1467276

ABSTRACT

The three classes of interferons (IFNs) share the ability to inhibit viral replication, activating cell transcriptional programs that regulate both innate and adaptive responses to viral and intracellular bacterial challenge. Due to their unique potency in regulating viral replication, and their association with numerous autoimmune diseases, the tightly orchestrated transcriptional regulation of IFNs has long been a subject of intense investigation. The protective role of early robust IFN responses in the context of infection with SARS-CoV-2 has further underscored the relevance of these pathways. In this viewpoint, rather than focusing on the downstream effects of IFN signaling (which have been extensively reviewed elsewhere), we will summarize the historical and current understanding of the stepwise assembly and function of factors that regulate IFNß enhancer activity (the "enhanceosome") and highlight opportunities for deeper understanding of the transcriptional control of the ifnb gene.


Subject(s)
Epigenesis, Genetic , Gene Expression Regulation , Host-Pathogen Interactions/physiology , Interferon-beta/genetics , CCAAT-Enhancer-Binding Proteins/genetics , CCAAT-Enhancer-Binding Proteins/metabolism , DNA Methylation , Enhancer Elements, Genetic , Host-Pathogen Interactions/genetics , Humans , Influenza A Virus, H5N1 Subtype/pathogenicity , Interferon-beta/metabolism , Promoter Regions, Genetic , SARS-CoV-2/pathogenicity , Transcription, Genetic , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism
4.
Int J Mol Sci ; 22(19)2021 Oct 01.
Article in English | MEDLINE | ID: covidwho-1463708

ABSTRACT

Social behavioral changes, including social isolation or loneliness, increase the risk for stress-related disorders, such as major depressive disorder, posttraumatic stress disorder (PTSD), and suicide, which share a strong neuroinflammatory etiopathogenetic component. The peroxisome-proliferator activated receptor (PPAR)-α, a newly discovered target involved in emotional behavior regulation, is a ligand-activated nuclear receptor and a transcription factor that, following stimulation by endogenous or synthetic ligands, may induce neuroprotective effects by modulating neuroinflammation, and improve anxiety and depression-like behaviors by enhancing neurosteroid biosynthesis. How stress affects epigenetic mechanisms with downstream effects on inflammation and emotional behavior remains poorly understood. We studied the effects of 4-week social isolation, using a mouse model of PTSD/suicide-like behavior, on hippocampal PPAR-α epigenetic modification. Decreased PPAR-α expression in the hippocampus of socially isolated mice was associated with increased levels of methylated cytosines of PPAR-α gene CpG-rich fragments and deficient neurosteroid biosynthesis. This effect was associated with increased histone deacetylases (HDAC)1, methyl-cytosine binding protein (MeCP)2 and decreased ten-eleven translocator (TET)2 expression, which favor hypermethylation. These alterations were associated with increased TLR-4 and pro-inflammatory markers (e.g., TNF-α,), mediated by NF-κB signaling in the hippocampus of aggressive mice. This study contributes the first evidence of stress-induced brain PPAR-α epigenetic regulation. Social isolation stress may constitute a risk factor for inflammatory-based psychiatric disorders associated with neurosteroid deficits, and targeting epigenetic marks linked to PPAR-α downregulation may offer a valid therapeutic approach.


Subject(s)
Aggression , Hippocampus/metabolism , Inflammation/etiology , PPAR alpha/genetics , Social Isolation , Stress, Psychological , Aggression/psychology , Animals , Behavior, Animal , Chromatin Assembly and Disassembly , CpG Islands , Disease Models, Animal , Disease Susceptibility , Epigenesis, Genetic , Gene Expression , Inflammation/metabolism , Inflammation Mediators/metabolism , Male , Methylation , Mice , PPAR alpha/metabolism , Promoter Regions, Genetic , Signal Transduction
7.
Cytokine ; 148: 155697, 2021 12.
Article in English | MEDLINE | ID: covidwho-1385382

ABSTRACT

The prevalence of SARS-CoV-2 is a great threat to global public health. However, the relationship between the viral pathogen SARS-CoV-2 and host innate immunity has not yet been well studied. The genome of SARS-CoV-2 encodes a viral protease called 3C-like protease. This protease is responsible for cleaving viral polyproteins during replication. In this investigation, 293T cells were transfected with SARS-CoV-2 3CL and then infected with Sendai virus (SeV) to induce the RIG-I like receptor (RLR)-based immune pathway. q-PCR, luciferase reporter assays, and western blotting were used for experimental analyses. We found that SARS-CoV-2 3CL significantly downregulated IFN-ß mRNA levels. Upon SeV infection, SARS-CoV-2 3CL inhibited the nuclear translocation of IRF3 and p65 and promoted the degradation of IRF3. This effect of SARS-CoV-2 3CL on type I IFN in the RLR immune pathway opens up novel ideas for future research on SARS-CoV-2.


Subject(s)
Coronavirus 3C Proteases/metabolism , Interferon Regulatory Factor-3/metabolism , Interferon-beta/biosynthesis , Proteolysis , DEAD Box Protein 58/metabolism , Gene Expression Regulation , HEK293 Cells , Humans , Interferon-beta/genetics , NF-kappa B/genetics , Promoter Regions, Genetic/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Immunologic/metabolism , Response Elements/genetics , Sendai virus/physiology , Signal Transduction
8.
JCI Insight ; 6(19)2021 10 08.
Article in English | MEDLINE | ID: covidwho-1379698

ABSTRACT

COVID-19, caused by SARS-CoV-2, has spread worldwide with dire consequences. To urgently investigate the pathogenicity of COVID-19 and develop vaccines and therapeutics, animal models that are highly susceptible to SARS-CoV-2 infection are needed. In the present study, we established an animal model highly susceptible to SARS-CoV-2 via the intratracheal tract infection in CAG promoter-driven human angiotensin-converting enzyme 2-transgenic (CAG-hACE2) mice. The CAG-hACE2 mice showed several severe symptoms of SARS-CoV-2 infection, with definitive weight loss and subsequent death. Acute lung injury with elevated cytokine and chemokine levels was observed at an early stage of infection in CAG-hACE2 mice infected with SARS-CoV-2. Analysis of the hACE2 gene in CAG-hACE2 mice revealed that more than 15 copies of hACE2 genes were integrated in tandem into the mouse genome, supporting the high susceptibility to SARS-CoV-2. In the developed model, immunization with viral antigen or injection of plasma from immunized mice prevented body weight loss and lethality due to infection with SARS-CoV-2. These results indicate that a highly susceptible model of SARS-CoV-2 infection in CAG-hACE2 mice via the intratracheal tract is suitable for evaluating vaccines and therapeutic medicines.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , COVID-19/genetics , Animals , COVID-19/pathology , Disease Models, Animal , Disease Susceptibility , Female , Male , Mice, Inbred C57BL , Mice, Transgenic , Promoter Regions, Genetic , SARS-CoV-2/isolation & purification
9.
J Virol ; 95(17): e0074721, 2021 08 10.
Article in English | MEDLINE | ID: covidwho-1356909

ABSTRACT

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is bringing an unprecedented health crisis to the world. To date, our understanding of the interaction between SARS-CoV-2 and host innate immunity is still limited. Previous studies reported that SARS-CoV-2 nonstructural protein 12 (NSP12) was able to suppress interferon-ß (IFN-ß) activation in IFN-ß promoter luciferase reporter assays, which provided insights into the pathogenesis of COVID-19. In this study, we demonstrated that IFN-ß promoter-mediated luciferase activity was reduced during coexpression of NSP12. However, we could show NSP12 did not affect IRF3 or NF-κB activation. Moreover, IFN-ß production induced by Sendai virus (SeV) infection or other stimulus was not affected by NSP12 at mRNA or protein level. Additionally, the type I IFN signaling pathway was not affected by NSP12, as demonstrated by the expression of interferon-stimulated genes (ISGs). Further experiments revealed that different experiment systems, including protein tags and plasmid backbones, could affect the readouts of IFN-ß promoter luciferase assays. In conclusion, unlike as previously reported, our study showed SARS-CoV-2 NSP12 protein is not an IFN-ß antagonist. It also rings the alarm on the general usage of luciferase reporter assays in studying SARS-CoV-2. IMPORTANCE Previous studies investigated the interaction between SARS-CoV-2 viral proteins and interferon signaling and proposed that several SARS-CoV-2 viral proteins, including NSP12, could suppress IFN-ß activation. However, most of these results were generated from IFN-ß promoter luciferase reporter assay and have not been validated functionally. In our study, we found that, although NSP12 could suppress IFN-ß promoter luciferase activity, it showed no inhibitory effect on IFN-ß production or its downstream signaling. Further study revealed that contradictory results could be generated from different experiment systems. On one hand, we demonstrated that SARS-CoV-2 NSP12 could not suppress IFN-ß signaling. On the other hand, our study suggests that caution needs to be taken with the interpretation of SARS-CoV-2-related luciferase assays.


Subject(s)
Coronavirus RNA-Dependent RNA Polymerase , Interferon-beta , Promoter Regions, Genetic , SARS-CoV-2 , Coronavirus RNA-Dependent RNA Polymerase/genetics , Coronavirus RNA-Dependent RNA Polymerase/metabolism , HEK293 Cells , Humans , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Interferon-beta/antagonists & inhibitors , Interferon-beta/biosynthesis , Interferon-beta/genetics , NF-kappa B/genetics , NF-kappa B/metabolism , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , SARS-CoV-2/genetics , SARS-CoV-2/metabolism
10.
J Virol ; 95(17): e0074721, 2021 08 10.
Article in English | MEDLINE | ID: covidwho-1350002

ABSTRACT

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is bringing an unprecedented health crisis to the world. To date, our understanding of the interaction between SARS-CoV-2 and host innate immunity is still limited. Previous studies reported that SARS-CoV-2 nonstructural protein 12 (NSP12) was able to suppress interferon-ß (IFN-ß) activation in IFN-ß promoter luciferase reporter assays, which provided insights into the pathogenesis of COVID-19. In this study, we demonstrated that IFN-ß promoter-mediated luciferase activity was reduced during coexpression of NSP12. However, we could show NSP12 did not affect IRF3 or NF-κB activation. Moreover, IFN-ß production induced by Sendai virus (SeV) infection or other stimulus was not affected by NSP12 at mRNA or protein level. Additionally, the type I IFN signaling pathway was not affected by NSP12, as demonstrated by the expression of interferon-stimulated genes (ISGs). Further experiments revealed that different experiment systems, including protein tags and plasmid backbones, could affect the readouts of IFN-ß promoter luciferase assays. In conclusion, unlike as previously reported, our study showed SARS-CoV-2 NSP12 protein is not an IFN-ß antagonist. It also rings the alarm on the general usage of luciferase reporter assays in studying SARS-CoV-2. IMPORTANCE Previous studies investigated the interaction between SARS-CoV-2 viral proteins and interferon signaling and proposed that several SARS-CoV-2 viral proteins, including NSP12, could suppress IFN-ß activation. However, most of these results were generated from IFN-ß promoter luciferase reporter assay and have not been validated functionally. In our study, we found that, although NSP12 could suppress IFN-ß promoter luciferase activity, it showed no inhibitory effect on IFN-ß production or its downstream signaling. Further study revealed that contradictory results could be generated from different experiment systems. On one hand, we demonstrated that SARS-CoV-2 NSP12 could not suppress IFN-ß signaling. On the other hand, our study suggests that caution needs to be taken with the interpretation of SARS-CoV-2-related luciferase assays.


Subject(s)
Coronavirus RNA-Dependent RNA Polymerase , Interferon-beta , Promoter Regions, Genetic , SARS-CoV-2 , Coronavirus RNA-Dependent RNA Polymerase/genetics , Coronavirus RNA-Dependent RNA Polymerase/metabolism , HEK293 Cells , Humans , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Interferon-beta/antagonists & inhibitors , Interferon-beta/biosynthesis , Interferon-beta/genetics , NF-kappa B/genetics , NF-kappa B/metabolism , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , SARS-CoV-2/genetics , SARS-CoV-2/metabolism
11.
Viruses ; 13(8)2021 07 23.
Article in English | MEDLINE | ID: covidwho-1325791

ABSTRACT

A weak production of INF-ß along with an exacerbated release of pro-inflammatory cytokines have been reported during infection by the novel SARS-CoV-2 virus. SARS-CoV-2 encodes several proteins able to counteract the host immune system, which is believed to be one of the most important features contributing to the viral pathogenesis and development of a severe clinical picture. Previous reports have demonstrated that SARS-CoV-2 N protein, along with some non-structural and accessory proteins, efficiently suppresses INF-ß production by interacting with RIG-I, an important pattern recognition receptor (PRR) involved in the recognition of pathogen-derived molecules. In the present study, we better characterized the mechanism by which the SARS-CoV-2 N counteracts INF-ß secretion and affects RIG-I signaling pathways. In detail, when the N protein was ectopically expressed, we noted a marked decrease in TRIM25-mediated RIG-I activation. The capability of the N protein to bind to, and probably mask, TRIM25 could be the consequence of its antagonistic activity. Furthermore, this interaction occurred at the SPRY domain of TRIM25, harboring the RNA-binding activity necessary for TRIM25 self-activation. Here, we describe new findings regarding the interplay between SARS-CoV-2 and the IFN system, filling some gaps for a better understanding of the molecular mechanisms affecting the innate immune response in COVID-19.


Subject(s)
COVID-19/immunology , Coronavirus Nucleocapsid Proteins/immunology , DEAD Box Protein 58/immunology , Receptors, Immunologic/immunology , SARS-CoV-2/immunology , Transcription Factors/immunology , Tripartite Motif Proteins/immunology , Ubiquitin-Protein Ligases/immunology , COVID-19/genetics , COVID-19/virology , Coronavirus Nucleocapsid Proteins/genetics , DEAD Box Protein 58/genetics , Gene Expression Regulation , Host-Pathogen Interactions , Humans , Immunity, Innate , Interferon-beta/genetics , Interferon-beta/immunology , Promoter Regions, Genetic , Receptors, Immunologic/genetics , SARS-CoV-2/genetics , Signal Transduction , Transcription Factors/genetics , Tripartite Motif Proteins/genetics , Ubiquitin-Protein Ligases/genetics
12.
Front Immunol ; 12: 648815, 2021.
Article in English | MEDLINE | ID: covidwho-1325521

ABSTRACT

Multiple lines of evidence have demonstrated that cigarette smoke or Chronic Obstructive Pulmonary Disease upregulates angiotensin-converting enzyme 2, the cellular receptor for the entry of the severe acute respiratory syndrome coronavirus 2, which predisposes individuals to develop severe Coronavirus disease 2019. The reason for this observation is unknown. We recently reported that the loss of function of Miz1 in the lung epithelium in mice leads to a spontaneous COPD-like phenotype, associated with upregulation of angiotensin-converting enzyme 2. We also reported that cigarette smoke exposure downregulates Miz1 in lung epithelial cells and in mice, and Miz1 is also downregulated in the lungs of COPD patients. Here, we provide further evidence that Miz1 directly binds to and represses the promoter of angiotensin-converting enzyme 2 in mouse and human lung epithelial cells. Our data provide a potential molecular mechanism for the upregulation of angiotensin-converting enzyme 2 observed in smokers and COPD patients, with implication in severe Coronavirus disease 2019.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Kruppel-Like Transcription Factors/metabolism , Receptors, Virus/genetics , Transcription, Genetic , Alveolar Epithelial Cells/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Animals , BTB-POZ Domain , Cell Line , Cigarette Smoking/adverse effects , Kruppel-Like Transcription Factors/chemistry , Kruppel-Like Transcription Factors/genetics , Mice , Promoter Regions, Genetic , Protein Binding , Receptors, Virus/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , Transcription, Genetic/drug effects , Tumor Necrosis Factors/pharmacology , Virus Internalization
13.
Int J Mol Sci ; 22(13)2021 Jun 28.
Article in English | MEDLINE | ID: covidwho-1288900

ABSTRACT

A group of clinically approved cancer therapeutic tyrosine kinase inhibitors was screened to test their effects on the expression of angiotensin-converting enzyme 2 (ACE2), the cell surface receptor for SARS-CoV-2. Here, we show that the receptor tyrosine kinase inhibitor imatinib (also known as STI571, Gleevec) can inhibit the expression of the endogenous ACE2 gene at both the transcript and protein levels. Treatment with imatinib resulted in inhibition of cell entry of the viral pseudoparticles (Vpps) in cell culture. In FVB mice orally fed imatinib, tissue expression of ACE2 was reduced, specifically in the lungs and renal tubules, but not in the parenchyma of other organs such as the heart and intestine. Our finding suggests that receptor tyrosine kinases play a role in COVID-19 infection and can be therapeutic targets with combined treatments of the best conventional care of COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Down-Regulation/drug effects , Imatinib Mesylate/pharmacology , SARS-CoV-2/physiology , Virus Internalization/drug effects , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/pathology , COVID-19/virology , Cell Line , Cell Survival/drug effects , Chlorocebus aethiops , Female , Genes, Reporter , Humans , Mice , Promoter Regions, Genetic , SARS-CoV-2/isolation & purification
15.
J Cell Mol Med ; 25(16): 7825-7839, 2021 08.
Article in English | MEDLINE | ID: covidwho-1280337

ABSTRACT

The new coronavirus pandemic started in China in 2019. The intensity of the disease can range from mild to severe, leading to death in many cases. Despite extensive research in this area, the exact molecular nature of virus is not fully recognized; however, according to pieces of evidence, one of the mechanisms of virus pathogenesis is through the function of viral miRNAs. So, we hypothesized that SARS-CoV-2 pathogenesis may be due to targeting important genes in the host with its miRNAs, which involved in the respiratory system, immune pathways and vitamin D pathways, thus possibly contributing to disease progression and virus survival. Potential miRNA precursors and mature miRNA were predicted and confirmed based on the virus genome. The next step was to predict and identify their target genes and perform functional enrichment analysis to recognize the biological processes connected with these genes in the three pathways mentioned above through several comprehensive databases. Finally, cis-acting regulatory elements in 5' regulatory regions were analysed, and the analysis of available RNAseq data determined the expression level of genes. We revealed that thirty-nine mature miRNAs could theoretically derive from the SARS-CoV-2 genome. Functional enrichment analysis elucidated three highlighted pathways involved in SARS-CoV-2 pathogenesis: vitamin D, immune system and respiratory system. Our finding highlighted genes' involvement in three crucial molecular pathways and may help develop new therapeutic targets related to SARS-CoV-2.


Subject(s)
COVID-19/immunology , Host-Pathogen Interactions/physiology , MicroRNAs , SARS-CoV-2/genetics , Vitamin D/metabolism , COVID-19/genetics , COVID-19/virology , Gene Expression Regulation , Humans , Immune System/virology , Molecular Sequence Annotation , Promoter Regions, Genetic , RNA, Viral , Respiratory System/virology , SARS-CoV-2/pathogenicity
16.
Nutrition ; 89: 111340, 2021 09.
Article in English | MEDLINE | ID: covidwho-1265813

ABSTRACT

OBJECTIVES: The viral entry of SARS-CoV-2 requires host-expressed TMPRSS2 to facilitate the viral spike protein priming. This study aims to test the hypothesis that magnesium (Mg) treatment leads to DNA methylation changes in TMPRSS2. METHODS: This study is nested within the Personalized Prevention of Colorectal Cancer Trial, a double-blind 2 × 2 factorial randomized controlled trial, which enrolled 250 participants from Vanderbilt University Medical Center. RESULTS: We found that 12 wk of personalized Mg treatment significantly increased 5-methylcytosine methylation at cg16371860 (TSS1500, promoter) by 7.2% compared to the placebo arm (decreased by 0.1%) in those ages < 65 y. The difference remained statistically significant after adjusting for age, sex, and baseline methylation as well as correction for false discovery rate (adjusted P = 0.014). Additionally, Mg treatment significantly reduced 5-hydroxymethylcytosine levels at cg26337277 (close proximity to TSS200 and the 5' untranslated region, promoter) by 2.3% compared to an increase of 7.1% in the placebo arm after adjusting for covariates in those ages < 65 y (P = 0.003). The effect remained significant at a false discovery rate of 0.10 (adjusted P = 0.088). CONCLUSIONS: Among individuals ages < 65 y with calcium-to-magnesium intake ratios equal to or over 2.6, reducing the ratio to around 2.3 increased 5-methylcytosine modifications (i.e., cg16371860) and reduced 5-hydroxymethylcytosine modifications (i.e., cg26337277) in the TMPRSS2 gene. These findings, if confirmed, provide another mechanism for the role of Mg intervention in the prevention of COVID-19 and treatment of early and mild disease by modifying the phenotype of the TMPRSS2 genotype.


Subject(s)
COVID-19 , Magnesium , DNA Methylation , Humans , Promoter Regions, Genetic , SARS-CoV-2 , Serine Endopeptidases
18.
Cells ; 10(4)2021 04 15.
Article in English | MEDLINE | ID: covidwho-1232577

ABSTRACT

Thrombin, the ligand of the protease-activated receptor 1 (PAR1), is a well-known stimulator of proangiogenic responses in vascular endothelial cells (ECs), which are mediated through the induction of vascular endothelial growth factor (VEGF). However, the transcriptional events underlying this thrombin-induced VEGF induction and angiogenic response are less well understood at present. As reported here, we conducted detailed promotor activation and signal transduction pathway studies in human microvascular ECs, to decipher the transcription factors and the intracellular signaling events underlying the thrombin and PAR-1-induced endothelial VEGF induction. We found that c-FOS is a key transcription factor controlling thrombin-induced EC VEGF synthesis and angiogenesis. Upon the binding and internalization of its G-protein-coupled PAR-1 receptor, thrombin triggers ERK1/2 signaling and activation of the nuclear AP-1/c-FOS transcription factor complex, which then leads to VEGF transcription, extracellular secretion, and concomitant proangiogenic responses of ECs. In conclusion, exposure of human microvascular ECs to thrombin triggers signaling through the PAR-1-ERK1/2-AP-1/c-FOS axis to control VEGF gene transcription and VEGF-induced angiogenesis. These observations offer a greater understanding of endothelial responses to thromboinflammation, which may help to interpret the results of clinical trials tackling the conditions associated with endothelial injury and thrombosis.


Subject(s)
Gene Expression Regulation , Neovascularization, Physiologic/genetics , Thrombin/pharmacology , Transcription, Genetic/drug effects , Vascular Endothelial Growth Factor A/metabolism , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors , Extracellular Signal-Regulated MAP Kinases/metabolism , Gene Expression Regulation/drug effects , Humans , Microvessels/pathology , Neovascularization, Physiologic/drug effects , Promoter Regions, Genetic/genetics , Proto-Oncogene Proteins c-jun/metabolism , Receptor, PAR-1/metabolism , Transcription Factor AP-1/metabolism , Vascular Endothelial Growth Factor A/genetics
19.
Genome ; 64(4): 386-399, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1183386

ABSTRACT

The angiotensin-converting enzyme 2 (ACE2) is the receptor for the three coronaviruses HCoV-NL63, SARS-CoV, and SARS-CoV-2. ACE2 is involved in the regulation of the renin-angiotensin system and blood pressure. ACE2 is also involved in the regulation of several signaling pathways, including integrin signaling. ACE2 expression is regulated transcriptionally and post-transcriptionally. The expression of the gene is regulated by two promoters, with usage varying among tissues. ACE2 expression is greatest in the small intestine, kidney, and heart and detectable in a variety of tissues and cell types. Herein we review the chemical and mechanical signal transduction pathways regulating the expression of the ACE2 gene and the epigenetic/chromatin features of the expressed gene.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , Epigenesis, Genetic , Receptors, Virus/genetics , COVID-19 , Gene Expression Regulation , Humans , Promoter Regions, Genetic , Protein Processing, Post-Translational , Renin-Angiotensin System , SARS-CoV-2 , Signal Transduction
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