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2.
Stem Cell Reports ; 17(3): 538-555, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1692861

ABSTRACT

To date, the direct causative mechanism of SARS-CoV-2-induced endotheliitis remains unclear. Here, we report that human ECs barely express surface ACE2, and ECs express less intracellular ACE2 than non-ECs of the lungs. We ectopically expressed ACE2 in hESC-ECs to model SARS-CoV-2 infection. ACE2-deficient ECs are resistant to the infection but are more activated than ACE2-expressing ones. The virus directly induces endothelial activation by increasing monocyte adhesion, NO production, and enhanced phosphorylation of p38 mitogen-associated protein kinase (MAPK), NF-κB, and eNOS in ACE2-expressing and -deficient ECs. ACE2-deficient ECs respond to SARS-CoV-2 through TLR4 as treatment with its antagonist inhibits p38 MAPK/NF-κB/ interleukin-1ß (IL-1ß) activation after viral exposure. Genome-wide, single-cell RNA-seq analyses further confirm activation of the TLR4/MAPK14/RELA/IL-1ß axis in circulating ECs of mild and severe COVID-19 patients. Circulating ECs could serve as biomarkers for indicating patients with endotheliitis. Together, our findings support a direct role for SARS-CoV-2 in mediating endothelial inflammation in an ACE2-dependent or -independent manner.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Models, Biological , SARS-CoV-2/physiology , Toll-Like Receptor 4/metabolism , Angiotensin-Converting Enzyme 2/genetics , COVID-19/pathology , COVID-19/virology , Endothelial Cells/cytology , Endothelial Cells/metabolism , Gene Expression Profiling , Human Umbilical Vein Endothelial Cells , Humans , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , NF-kappa B/antagonists & inhibitors , NF-kappa B/genetics , NF-kappa B/metabolism , Pluripotent Stem Cells/cytology , Pluripotent Stem Cells/metabolism , SARS-CoV-2/isolation & purification , Severity of Illness Index , Single-Cell Analysis , Toll-Like Receptor 4/antagonists & inhibitors , Toll-Like Receptor 4/genetics , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
3.
Handb Exp Pharmacol ; 276: 1-21, 2022.
Article in English | MEDLINE | ID: covidwho-1653353

ABSTRACT

Toll-like receptors were discovered as proteins playing a crucial role in the dorsoventral patterning during embryonic development in the Drosophila melanogaster (D. melanogaster) almost 40 years ago. Subsequently, further research also showed a role of the Toll protein or Toll receptor in the recognition of Gram-positive bacterial and fungal pathogens infecting D. melanogaster. In 1997, the human homolog was reported and the receptor was named the Toll-like receptor 4 (TLR4) that recognizes lipopolysaccharide (LPS) of the Gram-negative bacteria as a pathogen-associated molecular pattern (PAMP). Identification of TLR4 in humans filled the long existing gap in the field of infection and immunity, addressing the mystery surrounding the recognition of foreign pathogens/microbes by the immune system. It is now known that mammals (mice and humans) express 13 different TLRs that are expressed on the outer cell membrane or intracellularly, and which recognize different PAMPs or microbe-associated molecular patterns (MAMPs) and death/damage-associated molecular patterns (DAMPs) to initiate the protective immune response. However, their dysregulation generates profound and prolonged pro-inflammatory immune responses responsible for different inflammatory and immune-mediated diseases. This chapter provides an overview of TLRs in the control of the immune response, their association with different diseases, including TLR single nucleotide polymorphisms (SNPs), interactions with microRNAs (miRs), use in drug development and vaccine design, and expansion in neurosciences to include pain, addiction, metabolism, reproduction, and wound healing.


Subject(s)
Drosophila melanogaster , Toll-Like Receptor 4 , Animals , Drosophila melanogaster/metabolism , Humans , Immunity, Innate , Mammals/metabolism , Mice , Polymorphism, Single Nucleotide , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Toll-Like Receptors/metabolism
4.
Int J Mol Med ; 49(2)2022 02.
Article in English | MEDLINE | ID: covidwho-1594678

ABSTRACT

The pathophysiology of coronavirus disease 2019 (COVID­19) is mainly dependent on the underlying mechanisms that mediate the entry of severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) into the host cells of the various human tissues/organs. Recent studies have indicated a higher order of complexity of the mechanisms of infectivity, given that there is a wide­repertoire of possible cell entry mediators that appear to co­localise in a cell­ and tissue­specific manner. The present study provides an overview of the 'canonical' SARS­CoV­2 mediators, namely angiotensin converting enzyme 2, transmembrane protease serine 2 and 4, and neuropilin­1, expanding on the involvement of novel candidates, including glucose­regulated protein 78, basigin, kidney injury molecule­1, metabotropic glutamate receptor subtype 2, ADAM metallopeptidase domain 17 (also termed tumour necrosis factor­α convertase) and Toll­like receptor 4. Furthermore, emerging data indicate that changes in microRNA (miRNA/miR) expression levels in patients with COVID­19 are suggestive of further complexity in the regulation of these viral mediators. An in silico analysis revealed 160 candidate miRNAs with potential strong binding capacity in the aforementioned genes. Future studies should concentrate on elucidating the association between the cellular tropism of the SARS­CoV­2 cell entry mediators and the mechanisms through which they might affect the clinical outcome. Finally, the clinical utility as a biomarker or therapeutic target of miRNAs in the context of COVID­19 warrants further investigation.


Subject(s)
COVID-19/metabolism , MicroRNAs/metabolism , Receptors, Virus/metabolism , SARS-CoV-2/metabolism , Virus Internalization , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/genetics , COVID-19/virology , /metabolism , Gene Expression Regulation , Host-Pathogen Interactions , Humans , Membrane Proteins/genetics , Membrane Proteins/metabolism , MicroRNAs/genetics , Neuropilin-1/genetics , Neuropilin-1/metabolism , Receptors, Virus/genetics , SARS-CoV-2/physiology , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Viral Tropism
5.
Elife ; 102021 04 27.
Article in English | MEDLINE | ID: covidwho-1513055

ABSTRACT

Dendritic cells (DCs) regulate processes ranging from antitumor and antiviral immunity to host-microbe communication at mucosal surfaces. It remains difficult, however, to genetically manipulate human DCs, limiting our ability to probe how DCs elicit specific immune responses. Here, we develop a CRISPR-Cas9 genome editing method for human monocyte-derived DCs (moDCs) that mediates knockouts with a median efficiency of >94% across >300 genes. Using this method, we perform genetic screens in moDCs, identifying mechanisms by which DCs tune responses to lipopolysaccharides from the human microbiome. In addition, we reveal donor-specific responses to lipopolysaccharides, underscoring the importance of assessing immune phenotypes in donor-derived cells, and identify candidate genes that control this specificity, highlighting the potential of our method to pinpoint determinants of inter-individual variation in immunity. Our work sets the stage for a systematic dissection of the immune signaling at the host-microbiome interface and for targeted engineering of DCs for neoantigen vaccination.


Subject(s)
CRISPR-Associated Protein 9/genetics , CRISPR-Cas Systems , Clustered Regularly Interspaced Short Palindromic Repeats , Dendritic Cells/immunology , Gene Editing , Genomics , Immunity, Innate/genetics , Bacteroides thetaiotaomicron/immunology , CRISPR-Associated Protein 9/metabolism , Cells, Cultured , Cytokines/genetics , Cytokines/metabolism , Dendritic Cells/drug effects , Dendritic Cells/metabolism , Gene Expression Regulation , Humans , Immunity, Innate/drug effects , Lipopolysaccharides/pharmacology , Phenotype , Signal Transduction , Toll-Like Receptor 4/agonists , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism
6.
Int J Mol Sci ; 22(13)2021 Jul 01.
Article in English | MEDLINE | ID: covidwho-1295859

ABSTRACT

Parkinson's disease (PD) is the most common neurodegenerative motor disorder characterized by selective degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) of the midbrain, depletion of dopamine (DA), and impaired nigrostriatal pathway. The pathological hallmark of PD includes the aggregation and accumulation α-synuclein (α-SYN). Although the precise mechanisms underlying the pathogenesis of PD are still unknown, the activation of toll-like receptors (TLRs), mainly TLR4 and subsequent neuroinflammatory immune response, seem to play a significant role. Mounting evidence suggests that viral infection can concur with the precipitation of PD or parkinsonism. The recently identified coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of ongoing pandemic coronavirus disease 2019 (COVID-19), responsible for 160 million cases that led to the death of more than three million individuals worldwide. Studies have reported that many patients with COVID-19 display several neurological manifestations, including acute cerebrovascular diseases, conscious disturbance, and typical motor and non-motor symptoms accompanying PD. In this review, the neurotropic potential of SARS-CoV-2 and its possible involvement in the pathogenesis of PD are discussed. Specifically, the involvement of the TLR4 signaling pathway in mediating the virus entry, as well as the massive immune and inflammatory response in COVID-19 patients is explored. The binding of SARS-CoV-2 spike (S) protein to TLR4 and the possible interaction between SARS-CoV-2 and α-SYN as contributing factors to neuronal death are also considered.


Subject(s)
COVID-19/physiopathology , Parkinson Disease/metabolism , Parkinson Disease/virology , SARS-CoV-2/metabolism , Toll-Like Receptor 4/metabolism , COVID-19/metabolism , Humans , Parkinson Disease/genetics , SARS-CoV-2/genetics , Signal Transduction , Spike Glycoprotein, Coronavirus/metabolism , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/physiology
7.
Int J Mol Sci ; 22(10)2021 May 15.
Article in English | MEDLINE | ID: covidwho-1236794

ABSTRACT

Acute lung injury (ALI) afflicts approximately 200,000 patients annually and has a 40% mortality rate. The COVID-19 pandemic has massively increased the rate of ALI incidence. The pathogenesis of ALI involves tissue damage from invading microbes and, in severe cases, the overexpression of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). This study aimed to develop a therapy to normalize the excess production of inflammatory cytokines and promote tissue repair in the lipopolysaccharide (LPS)-induced ALI. Based on our previous studies, we tested the insulin-like growth factor I (IGF-I) and BTP-2 therapies. IGF-I was selected, because we and others have shown that elevated inflammatory cytokines suppress the expression of growth hormone receptors in the liver, leading to a decrease in the circulating IGF-I. IGF-I is a growth factor that increases vascular protection, enhances tissue repair, and decreases pro-inflammatory cytokines. It is also required to produce anti-inflammatory 1,25-dihydroxyvitamin D. BTP-2, an inhibitor of cytosolic calcium, was used to suppress the LPS-induced increase in cytosolic calcium, which otherwise leads to an increase in proinflammatory cytokines. We showed that LPS increased the expression of the primary inflammatory mediators such as toll like receptor-4 (TLR-4), IL-1ß, interleukin-17 (IL-17), TNF-α, and interferon-γ (IFN-γ), which were normalized by the IGF-I + BTP-2 dual therapy in the lungs, along with improved vascular gene expression markers. The histologic lung injury score was markedly elevated by LPS and reduced to normal by the combination therapy. In conclusion, the LPS-induced increases in inflammatory cytokines, vascular injuries, and lung injuries were all improved by IGF-I + BTP-2 combination therapy.


Subject(s)
Acute Lung Injury/drug therapy , Acute Lung Injury/metabolism , Anilides/pharmacology , Cytokines/metabolism , Gene Expression Regulation/drug effects , Insulin-Like Growth Factor I/pharmacology , Thiadiazoles/pharmacology , Acute Lung Injury/pathology , Acute Lung Injury/virology , Anilides/therapeutic use , Animals , COVID-19/complications , Calcium/metabolism , Calcium Channels/metabolism , Cytokines/genetics , Disease Models, Animal , Female , Gene Expression Regulation/genetics , Immunohistochemistry , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor I/therapeutic use , Interferon-gamma/genetics , Interferon-gamma/metabolism , Interleukin-17/genetics , Interleukin-17/metabolism , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Lipopolysaccharides/toxicity , Mice , Mice, Inbred C57BL , Signal Transduction/drug effects , Signal Transduction/genetics , Thiadiazoles/therapeutic use , Toll-Like Receptor 4/genetics , Toll-Like Receptor 4/metabolism , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism
8.
Mol Pharm ; 18(6): 2233-2241, 2021 06 07.
Article in English | MEDLINE | ID: covidwho-1233685

ABSTRACT

Eliciting a robust immune response at mucosal sites is critical in preventing the entry of mucosal pathogens such as influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This task is challenging to achieve without the inclusion of a strong and safe mucosal adjuvant. Previously, inulin acetate (InAc), a plant-based polymer, is shown to activate toll-like receptor-4 (TLR4) and elicit a robust systemic immune response as a vaccine adjuvant. This study investigates the potential of nanoparticles prepared with InAc (InAc-NPs) as an intranasal vaccine delivery system to generate both mucosal and systemic immune responses. InAc-NPs (∼250 nm in diameter) activated wild-type (WT) macrophages but failed to activate macrophages from TLR4 knockout mice or WT macrophages when pretreated with a TLR4 antagonist (lipopolysaccharide-RS (LPS-RS)), which indicates the selective nature of a InAc-based nanodelivery system as a TLR4 agonist. Intranasal immunization using antigen-loaded InAc-NPs generated ∼65-fold and 19-fold higher serum IgG1 and IgG2a titers against the antigen, respectively, as compared to PLGA-NPs as a delivery system. InAc-NPs have also stimulated the secretion of sIgA at various mucosal sites, including nasal-associated lymphoid tissues (NALTs), lungs, and intestine, and produced a strong memory response indicative of both humoral and cellular immune activation. Overall, by stimulating both systemic and mucosal immunity, InAc-NPs laid a basis for a potential intranasal delivery system for mucosal vaccination.


Subject(s)
Adjuvants, Immunologic/pharmacology , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Drug Carriers/pharmacology , Inulin/pharmacology , Adjuvants, Immunologic/chemistry , Administration, Intranasal , Animals , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/immunology , Cells, Cultured , Drug Carriers/chemistry , Drug Evaluation, Preclinical , Humans , Immunity, Mucosal/drug effects , Immunity, Mucosal/immunology , Immunogenicity, Vaccine , Inulin/chemistry , Inulin/immunology , Macrophages/drug effects , Macrophages/immunology , Male , Mice , Mice, Knockout , Nanoparticles/chemistry , Primary Cell Culture , SARS-CoV-2/immunology , Toll-Like Receptor 4/agonists , Toll-Like Receptor 4/genetics
9.
Int J Mol Sci ; 22(9)2021 May 10.
Article in English | MEDLINE | ID: covidwho-1231496

ABSTRACT

In addition to its canonical functions, vitamin D has been proposed to be an important mediator of the immune system. Despite ample sunshine, vitamin D deficiency is prevalent (>80%) in the Middle East, resulting in a high rate of supplementation. However, the underlying molecular mechanisms of the specific regimen prescribed and the potential factors affecting an individual's response to vitamin D supplementation are not well characterized. Our objective is to describe the changes in the blood transcriptome and explore the potential mechanisms associated with vitamin D3 supplementation in one hundred vitamin D-deficient women who were given a weekly oral dose (50,000 IU) of vitamin D3 for three months. A high-throughput targeted PCR, composed of 264 genes representing the important blood transcriptomic fingerprints of health and disease states, was performed on pre and post-supplementation blood samples to profile the molecular response to vitamin D3. We identified 54 differentially expressed genes that were strongly modulated by vitamin D3 supplementation. Network analyses showed significant changes in the immune-related pathways such as TLR4/CD14 and IFN receptors, and catabolic processes related to NF-kB, which were subsequently confirmed by gene ontology enrichment analyses. We proposed a model for vitamin D3 response based on the expression changes of molecules involved in the receptor-mediated intra-cellular signaling pathways and the ensuing predicted effects on cytokine production. Overall, vitamin D3 has a strong effect on the immune system, G-coupled protein receptor signaling, and the ubiquitin system. We highlighted the major molecular changes and biological processes induced by vitamin D3, which will help to further investigate the effectiveness of vitamin D3 supplementation among individuals in the Middle East as well as other regions.


Subject(s)
Cholecalciferol/genetics , Immunomodulation/immunology , Lipopolysaccharide Receptors/genetics , Toll-Like Receptor 4/genetics , Vitamin D/genetics , Adolescent , Adult , Cholecalciferol/administration & dosage , Cholecalciferol/immunology , Dietary Supplements , Female , Gene Expression/drug effects , Humans , Immunomodulation/drug effects , Nutrition Therapy , Vitamin D/immunology , Vitamin D Deficiency/diet therapy , Vitamin D Deficiency/genetics , Vitamin D Deficiency/immunology , Vitamin D Deficiency/pathology , Young Adult
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