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1.
Cell Transplant ; 30: 9636897211054481, 2021.
Article in English | MEDLINE | ID: covidwho-1511642

ABSTRACT

Biological and cellular interleukin-6 (IL-6)-related therapies have been used to treat severe COVID-19 pneumonia with hyperinflammatory syndrome and acute respiratory failure, which prompted further exploration of the role of IL-6 in human umbilical cord mesenchymal stem cell (hUCMSC) therapy. Peripheral blood mononuclear cells (PBMCs) were responders cocultured with hUCMSCs or exogenous IL-6. A PBMC suppression assay was used to analyze the anti-inflammatory effects via MTT assay. The IL-6 concentration in the supernatant was measured using ELISA. The correlation between the anti-inflammatory effect of hUCMSCs and IL-6 levels and the relevant roles of IL-6 and IL-6 mRNA expression was analyzed using the MetaCore functional network constructed from gene microarray data. The location of IL-6 and IL-6 receptor (IL-6R) expression was further evaluated. We reported that hUCMSCs did not initially exert any inhibitory effect on PHA-stimulated proliferation; however, a potent inhibitory effect on PHA-stimulated proliferation was observed, and the IL-6 concentration reached approximately 1000 ng/mL after 72 hours. Exogenous 1000 ng/mL IL-6 inhibited PHA-stimulated inflammation but less so than hUCMSCs. The inhibitory effects of hUCMSCs on PHA-stimulated PBMCs disappeared after adding an IL-6 neutralizing antibody or pretreatment with tocilizumab (TCZ), an IL-6R antagonist. hUCMSCs exert excellent anti-inflammatory effects by inducing higher IL-6 levels, which is different from TCZ. High concentration of IL-6 cytokine secretion plays an important role in the anti-inflammatory effect of hUCMSC therapy. Initial hUCMSC therapy, followed by TCZ, seems to optimize the therapeutic potential to treat COVID-19-related acute respiratory distress syndrome (ARDS).


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , COVID-19/complications , Interleukin-6/biosynthesis , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/metabolism , Respiratory Distress Syndrome/therapy , SARS-CoV-2 , Antibodies, Monoclonal, Humanized/pharmacology , Antibodies, Neutralizing/immunology , Cells, Cultured , Coculture Techniques , Combined Modality Therapy , DNA, Complementary/genetics , Gene Expression Regulation/drug effects , Humans , Inflammation , Interleukin-6/genetics , Interleukin-6/pharmacology , Leukocytes, Mononuclear/cytology , Leukocytes, Mononuclear/drug effects , Leukocytes, Mononuclear/metabolism , Lymphocyte Activation/drug effects , Phytohemagglutinins/pharmacology , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Receptors, Interleukin-6/antagonists & inhibitors , Receptors, Interleukin-6/biosynthesis , Receptors, Interleukin-6/genetics , Respiratory Distress Syndrome/drug therapy , Respiratory Distress Syndrome/etiology , Umbilical Cord/cytology
2.
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
3.
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
4.
Biomed Pharmacother ; 141: 111835, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1271574

ABSTRACT

Thymic stromal lymphopoietin (TSLP) produced by mast cells is involved in allergic inflammation pathogenesis. Chloroquine (CQ) is known to be an anti-malarial drug; however, additional protective functions of CQ have been discovered. This study aims to clarify an anti-inflammatory effect of CQ through modulating TSLP levels using an in vitro model of phorbol myristate acetate (PMA) + A23187-activated human mast cell line (HMC-1) and an in vivo model of PMA-irritated ear edema. CQ treatment reduced the production and mRNA expression levels of TSLP in activated HMC-1 cells. CQ down-regulated caspase-1 (CASP1), MAPKs, and NF-κB levels enhanced by stimulation with PMA + A23187. Moreover, ear thickness in ear edema was suppressed following CQ treatment. CQ decreased CASP1 and NF-κB levels in the ear tissue. TSLP levels in the ear tissue and serum were reduced following CQ treatment. Collectively, the above findings elucidate that CQ inhibits the pro-inflammatory mechanisms of TSLP via the down-regulation of distinct intracellular signaling cascade in mast cells. Therefore, CQ may have protective roles against TSLP-mediated inflammatory disorders.


Subject(s)
Caspase 1/drug effects , Caspase Inhibitors/pharmacology , Chloroquine/pharmacology , Cytokines/biosynthesis , Mast Cells/drug effects , Signal Transduction/drug effects , Stromal Cells/metabolism , Thymus Gland/metabolism , Animals , Calcimycin/pharmacology , Cell Line , Ear Diseases/drug therapy , Edema/drug therapy , Humans , MAP Kinase Signaling System/drug effects , Male , Mice , Mice, Inbred ICR , NF-kappa B/drug effects , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Stromal Cells/drug effects , Tetradecanoylphorbol Acetate/pharmacology , Thymus Gland/drug effects
5.
Elife ; 92020 11 09.
Article in English | MEDLINE | ID: covidwho-916539

ABSTRACT

Pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus 19 disease (COVID-19) which presents a large spectrum of manifestations with fatal outcomes in vulnerable people over 70-years-old and with hypertension, diabetes, obesity, cardiovascular disease, COPD, and smoking status. Knowledge of the entry receptor is key to understand SARS-CoV-2 tropism, transmission and pathogenesis. Early evidence pointed to angiotensin-converting enzyme 2 (ACE2) as SARS-CoV-2 entry receptor. Here, we provide a critical summary of the current knowledge highlighting the limitations and remaining gaps that need to be addressed to fully characterize ACE2 function in SARS-CoV-2 infection and associated pathogenesis. We also discuss ACE2 expression and potential role in the context of comorbidities associated with poor COVID-19 outcomes. Finally, we discuss the potential co-receptors/attachment factors such as neuropilins, heparan sulfate and sialic acids and the putative alternative receptors, such as CD147 and GRP78.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/virology , Peptidyl-Dipeptidase A/physiology , Pneumonia, Viral/virology , Virus Attachment , Angiotensin-Converting Enzyme 2 , Basigin/physiology , COVID-19 , Comorbidity , Coronavirus Infections/epidemiology , Gene Expression Regulation, Enzymologic , Heparitin Sulfate/physiology , Humans , Hypertension/epidemiology , Hypertension/physiopathology , Neuropilin-1/physiology , Oligopeptides/physiology , Organ Specificity , Pandemics , Pneumonia, Viral/epidemiology , Protein Binding , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Receptors, Virus , Renin-Angiotensin System/physiology , Respiratory System/enzymology , SARS-CoV-2 , Sialic Acids/physiology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/physiology , Virus Internalization
6.
PLoS One ; 15(10): e0240647, 2020.
Article in English | MEDLINE | ID: covidwho-895060

ABSTRACT

The World Health Organization declared the COVID-19 epidemic a public health emergency of international concern on March 11th, 2020, and the pandemic is rapidly spreading worldwide. COVID-19 is caused by a novel coronavirus SARS-CoV-2, which enters human target cells via angiotensin converting enzyme 2 (ACE2). We used a number of bioinformatics tools to computationally characterize ACE2 by determining its cell-specific expression in trachea, lung, and small intestine, derive its putative functions, and predict transcriptional regulation. The small intestine expressed higher levels of ACE2 mRNA than any other organ. By immunohistochemistry, duodenum, kidney and testis showed strong signals, whereas the signal was weak in the respiratory tract. Single cell RNA-Seq data from trachea indicated positive signals along the respiratory tract in key protective cell types including club, goblet, proliferating, and ciliary epithelial cells; while in lung the ratio of ACE2-expressing cells was low in all cell types (<2.6%), but was highest in vascular endothelial and goblet cells. Gene ontology analysis suggested that, besides its classical role in the renin-angiotensin system, ACE2 may be functionally associated with angiogenesis/blood vessel morphogenesis. Using a novel tool for the prediction of transcription factor binding sites we identified several putative binding sites within two tissue-specific promoters of the ACE2 gene as well as a new putative short form of ACE2. These include several interferon-stimulated response elements sites for STAT1, IRF8, and IRF9. Our results also confirmed that age and gender play no significant role in the regulation of ACE2 mRNA expression in the lung.


Subject(s)
Betacoronavirus/physiology , Computational Biology , Coronavirus Infections/virology , Pandemics , Peptidyl-Dipeptidase A/physiology , Pneumonia, Viral/virology , Receptors, Virus/physiology , Aging/metabolism , Angiotensin-Converting Enzyme 2 , Binding Sites , COVID-19 , Carrier Proteins/biosynthesis , Carrier Proteins/genetics , Female , Gene Expression Regulation, Enzymologic , Gene Ontology , Humans , Interferons/physiology , Lung/metabolism , Male , Metalloproteases/biosynthesis , Metalloproteases/genetics , Neovascularization, Physiologic/physiology , Organ Specificity , Peptidyl-Dipeptidase A/biosynthesis , Peptidyl-Dipeptidase A/genetics , Promoter Regions, Genetic , RNA, Messenger/biosynthesis , Receptors, Virus/biosynthesis , Receptors, Virus/genetics , Renin-Angiotensin System/physiology , SARS-CoV-2 , Sex Characteristics , Single-Cell Analysis , Transcription Factors/metabolism , Transcription Initiation Site , Virus Attachment
7.
Neuromolecular Med ; 23(1): 184-198, 2021 03.
Article in English | MEDLINE | ID: covidwho-871558

ABSTRACT

Ergothioneine (ET) is a naturally occurring antioxidant that is synthesized by non-yeast fungi and certain bacteria. ET is not synthesized by animals, including humans, but is avidly taken up from the diet, especially from mushrooms. In the current study, we elucidated the effect of ET on the hCMEC/D3 human brain endothelial cell line. Endothelial cells are exposed to high levels of the cholesterol oxidation product, 7-ketocholesterol (7KC), in patients with cardiovascular disease and diabetes, and this process is thought to mediate pathological inflammation. 7KC induces a dose-dependent loss of cell viability and an increase in apoptosis and necrosis in the endothelial cells. A relocalization of the tight junction proteins, zonula occludens-1 (ZO-1) and claudin-5, towards the nucleus of the cells was also observed. These effects were significantly attenuated by ET. In addition, 7KC induces marked increases in the mRNA expression of pro-inflammatory cytokines, IL-1ß IL-6, IL-8, TNF-α and cyclooxygenase-2 (COX2), as well as COX2 enzymatic activity, and these were significantly reduced by ET. Moreover, the cytoprotective and anti-inflammatory effects of ET were significantly reduced by co-incubation with an inhibitor of the ET transporter, OCTN1 (VHCL). This shows that ET needs to enter the endothelial cells to have a protective effect and is unlikely to act via extracellular neutralizing of 7KC. The protective effect on inflammation in brain endothelial cells suggests that ET might be useful as a nutraceutical for the prevention or management of neurovascular diseases, such as stroke and vascular dementia. Moreover, the ability of ET to cross the blood-brain barrier could point to its usefulness in combatting 7KC that is produced in the CNS during neuroinflammation, e.g. after excitotoxicity, in chronic neurodegenerative diseases, and possibly COVID-19-related neurologic complications.


Subject(s)
Antioxidants/pharmacology , COVID-19/complications , Endothelial Cells/drug effects , Ergothioneine/pharmacology , Ketocholesterols/toxicity , Nervous System Diseases/prevention & control , Neuroprotective Agents/pharmacology , Antioxidants/pharmacokinetics , Apoptosis/drug effects , Biological Transport , Blood-Brain Barrier , Brain/blood supply , Brain/cytology , Cell Line , Cholesterol/metabolism , Claudin-5 , Cyclooxygenase 2/biosynthesis , Cyclooxygenase 2/genetics , Cytokines/biosynthesis , Cytokines/genetics , Drug Evaluation, Preclinical , Ergothioneine/pharmacokinetics , Humans , Microvessels/cytology , Nervous System Diseases/etiology , Neuroprotective Agents/pharmacokinetics , Nitric Oxide Synthase Type II/metabolism , Nitric Oxide Synthase Type III/metabolism , Organic Cation Transport Proteins , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Symporters , Zonula Occludens-1 Protein
8.
mBio ; 11(5)2020 09 10.
Article in English | MEDLINE | ID: covidwho-760223

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), is a recently emerged respiratory coronavirus that has infected >23 million people worldwide with >800,000 deaths. Few COVID-19 therapeutics are available, and the basis for severe infections is poorly understood. Here, we investigated properties of type I (ß), II (γ), and III (λ1) interferons (IFNs), potent immune cytokines that are normally produced during infection and that upregulate IFN-stimulated gene (ISG) effectors to limit virus replication. IFNs are already in clinical trials to treat COVID-19. However, recent studies highlight the potential for IFNs to enhance expression of host angiotensin-converting enzyme 2 (ACE2), suggesting that IFN therapy or natural coinfections could exacerbate COVID-19 by upregulating this critical virus entry receptor. Using a cell line model, we found that beta interferon (IFN-ß) strongly upregulated expression of canonical antiviral ISGs, as well as ACE2 at the mRNA and cell surface protein levels. Strikingly, IFN-λ1 upregulated antiviral ISGs, but ACE2 mRNA was only marginally elevated and did not lead to detectably increased ACE2 protein at the cell surface. IFN-γ induced the weakest ISG response but clearly enhanced surface expression of ACE2. Importantly, all IFN types inhibited SARS-CoV-2 replication in a dose-dependent manner, and IFN-ß and IFN-λ1 exhibited potent antiviral activity in primary human bronchial epithelial cells. Our data imply that type-specific mechanisms or kinetics shape IFN-enhanced ACE2 transcript and cell surface levels but that the antiviral action of IFNs against SARS-CoV-2 counterbalances any proviral effects of ACE2 induction. These insights should aid in evaluating the benefits of specific IFNs, particularly IFN-λ, as repurposed therapeutics.IMPORTANCE Repurposing existing, clinically approved, antiviral drugs as COVID-19 therapeutics is a rapid way to help combat the SARS-CoV-2 pandemic. Interferons (IFNs) usually form part of the body's natural innate immune defenses against viruses, and they have been used with partial success to treat previous new viral threats, such as HIV, hepatitis C virus, and Ebola virus. Nevertheless, IFNs can have undesirable side effects, and recent reports indicate that IFNs upregulate the expression of host ACE2 (a critical entry receptor for SARS-CoV-2), raising the possibility that IFN treatments could exacerbate COVID-19. Here, we studied the antiviral- and ACE2-inducing properties of different IFN types in both a human lung cell line model and primary human bronchial epithelial cells. We observed differences between IFNs with respect to their induction of antiviral genes and abilities to enhance the cell surface expression of ACE2. Nevertheless, all the IFNs limited SARS-CoV-2 replication, suggesting that their antiviral actions can counterbalance increased ACE2.


Subject(s)
Antiviral Agents/pharmacology , Coronavirus Infections/drug therapy , Interferon Type I/pharmacology , Interferon-gamma/pharmacology , Interferons/pharmacology , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/drug therapy , Aged , Angiotensin-Converting Enzyme 2 , Animals , Betacoronavirus/immunology , COVID-19 , Cell Line , Chlorocebus aethiops , Female , Humans , Immunotherapy/methods , Interferon Type I/adverse effects , Interferon-gamma/adverse effects , Interferons/adverse effects , Pandemics , Peptidyl-Dipeptidase A/genetics , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , Receptors, Virus/metabolism , Respiratory Mucosa/cytology , Respiratory Mucosa/virology , SARS-CoV-2 , Up-Regulation/drug effects , Vero Cells , Virus Replication/drug effects
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