scholarly journals A simple model of COVID-19 explains disease severity and the effect of treatments

2021 ◽  
Author(s):  
Steven Sanche ◽  
Tyler Cassidy ◽  
Pinghan Chu ◽  
Alan S. Perelson ◽  
Ruy M. Ribeiro ◽  
...  
Keyword(s):  
Disease Severity ◽  
Treatment Strategies ◽  
Clinical Findings ◽  
Interferon Response ◽  
Type I ◽  
Infected Cells ◽  
New Treatment ◽  
High Level ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

ABSTRACTConsiderable effort was made to better understand why some people suffer from severe COVID-19 while others remain asymptomatic. This has led to important clinical findings; people with severe COVID-19 generally experience persistently high levels of inflammation, slower viral load decay, display a dysregulated type-I interferon response, have less active natural killer cells and increased levels of neutrophil extracellular traps. How these findings are connected to the pathogenesis of COVID-19 remains unclear. We propose a mathematical model that sheds light on this issue. The model focuses on cells that trigger inflammation through molecular patterns: infected cells carrying pathogen-associated molecular patterns (PAMPs) and damaged cells producing damage-associated molecular patterns (DAMPs). The former signals the presence of pathogens while the latter signals danger such as hypoxia or the lack of nutrients. Analyses show that SARS-CoV-2 infections can lead to a self-perpetuating feedback loop between DAMP expressing cells and inflammation. It identifies the inability to quickly clear PAMPs and DAMPs as the main contributor to hyperinflammation. The model explains clinical findings and the conditional impact of treatments on disease severity. The simplicity of the model and its high level of consistency with clinical findings motivate its use for the formulation of new treatment strategies.

scholarly journals Pattern recognition receptors in GtoPdb v.2021.3

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Clare Bryant ◽  
Tom P. Monie
Keyword(s):  
Pattern Recognition ◽  
Cell Attachment ◽  
Pattern Recognition Receptors ◽  
Interferon Response ◽  
Type I ◽  
Intracellular Proteins ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Microbial Agents ◽  
Oligomerization Domain

Pattern Recognition Receptors (PRRs, [104]) (nomenclature as agreed by NC-IUPHAR sub-committee on Pattern Recognition Receptors, [18]) participate in the innate immune response to microbial agents, the stimulation of which leads to activation of intracellular enzymes and regulation of gene transcription. PRRs express multiple leucine-rich regions to bind a range of microbially-derived ligands, termed PAMPs or pathogen-associated molecular patterns or endogenous ligands, termed DAMPS or damage-associated molecular patterns. These include peptides, carbohydrates, peptidoglycans, lipoproteins, lipopolysaccharides, and nucleic acids. PRRs include both cell-surface and intracellular proteins. PRRs may be divided into signalling-associated members, identified here, and endocytic members, the function of which appears to be to recognise particular microbial motifs for subsequent cell attachment, internalisation and destruction. Some are involved in inflammasome formation, and modulation of IL-1β cleavage and secretion, and others in the initiation of the type I interferon response. PRRs included in the Guide To PHARMACOLOGY are:Catalytic PRRs (see links below this overview)Toll-like receptors (TLRs)Nucleotide-binding oligomerization domain, leucine-rich repeat containing receptors (NLRs, also known as NOD (Nucleotide oligomerisation domain)-like receptors)RIG-I-like receptors (RLRs)Caspase 4 and caspase 5 Non-catalytic PRRsAbsent in melanoma (AIM)-like receptors (ALRs)C-type lectin-like receptors (CLRs)Other pattern recognition receptorsAdvanced glycosylation end-product specific receptor (RAGE)

scholarly journals Pattern recognition receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Clare Bryant ◽  
Tom P. Monie
Keyword(s):  
Pattern Recognition ◽  
Cell Attachment ◽  
Pattern Recognition Receptors ◽  
Interferon Response ◽  
Type I ◽  
Intracellular Proteins ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Microbial Agents ◽  
Oligomerization Domain

Pattern Recognition Receptors (PRRs, [83]) (nomenclature as agreed by NC-IUPHAR sub-committee on Pattern Recognition Receptors, [15]) participate in the innate immune response to microbial agents, the stimulation of which leads to activation of intracellular enzymes and regulation of gene transcription. PRRs express multiple leucine-rich regions to bind a range of microbially-derived ligands, termed PAMPs or pathogen-associated molecular patterns or endogenous ligands, termed DAMPS or damage-associated molecular patterns. These include peptides, carbohydrates, peptidoglycans, lipoproteins, lipopolysaccharides, and nucleic acids. PRRs include both cell-surface and intracellular proteins. PRRs may be divided into signalling-associated members, identified here, and endocytic members, the function of which appears to be to recognise particular microbial motifs for subsequent cell attachment, internalisation and destruction. Some are involved in inflammasome formation, and modulation of IL-1β cleavage and secretion, and others in the initiation of the type I interferon response. PRRs included in the Guide To PHARMACOLOGY are:Catalytic PRRs (see links below this overview)Toll-like receptors (TLRs)Nucleotide-binding oligomerization domain, leucine-rich repeat containing receptors (NLRs, also known as NOD (Nucleotide oligomerisation domain)-like receptors)RIG-I-like receptors (RLRs)Caspase 4 and caspase 5 Non-catalytic PRRsAbsent in melanoma (AIM)-like receptors (ALRs)C-type lectin-like receptors (CLRs)Other pattern recognition receptorsAdvanced glycosylation end-product specific receptor (RAGE)

scholarly journals Two Sides of the Coin: Mast Cells as a Key Regulator of Allergy and Acute/Chronic Inflammation

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1615
Author(s):  
Zhongwei Zhang ◽  
Yosuke Kurashima
Keyword(s):  
Mast Cells ◽  
Chronic Inflammation ◽  
Regulatory Function ◽  
Type I ◽  
Allergic Reactions ◽  
Novel Approach ◽  
Molecular Patterns ◽  
Regulatory Functions ◽  
Damage Associated Molecular Patterns ◽  
Two Sides

It is well known that mast cells (MCs) initiate type I allergic reactions and inflammation in a quick response to the various stimulants, including—but not limited to—allergens, pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs). MCs highly express receptors of these ligands and proteases (e.g., tryptase, chymase) and cytokines (TNF), and other granular components (e.g., histamine and serotonin) and aggravate the allergic reaction and inflammation. On the other hand, accumulated evidence has revealed that MCs also possess immune-regulatory functions, suppressing chronic inflammation and allergic reactions on some occasions. IL-2 and IL-10 released from MCs inhibit excessive immune responses. Recently, it has been revealed that allergen immunotherapy modulates the function of MCs from their allergic function to their regulatory function to suppress allergic reactions. This evidence suggests the possibility that manipulation of MCs functions will result in a novel approach to the treatment of various MCs-mediated diseases.

scholarly journals Biomarkers of Radiotherapy-Induced Immunogenic Cell Death

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 930
Author(s):  
Rianne D. W. Vaes ◽  
Lizza E. L. Hendriks ◽  
Marc Vooijs ◽  
Dirk De Ruysscher
Keyword(s):  
Cell Death ◽  
Immune Responses ◽  
Tumor Cells ◽  
Immunogenic Cell Death ◽  
Type I ◽  
Future Studies ◽  
Regulated Cell Death ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Potential Biomarkers

Radiation therapy (RT) can induce an immunogenic variant of regulated cell death that can initiate clinically relevant tumor-targeting immune responses. Immunogenic cell death (ICD) is accompanied by the exposure and release of damage-associated molecular patterns (DAMPs), chemokine release, and stimulation of type I interferon (IFN-I) responses. In recent years, intensive research has unraveled major mechanistic aspects of RT-induced ICD and has resulted in the identification of immunogenic factors that are released by irradiated tumor cells. However, so far, only a limited number of studies have searched for potential biomarkers that can be used to predict if irradiated tumor cells undergo ICD that can elicit an effective immunogenic anti-tumor response. In this article, we summarize the available literature on potential biomarkers of RT-induced ICD that have been evaluated in cancer patients. Additionally, we discuss the clinical relevance of these findings and important aspects that should be considered in future studies.

scholarly journals P03.24 Calreticulin exposure on malignant blasts correlates with improved NK cell-mediated cytotoxicity in AML patients

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A32.1-A32
Author(s):  
I Truxova ◽  
L Kasikova ◽  
C Salek ◽  
M Hensler ◽  
D Lysak ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Type I ◽  
Danger Signals ◽  
Hla Dr ◽  
Patient Prognosis ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

In some settings, cancer cells responding to treatment undergo an immunogenic form of cell death that is associated with the abundant emission of danger signals in the form of damage-associated molecular patterns. Accumulating preclinical and clinical evidence indicates that danger signals play a crucial role in the (re-)activation of antitumor immune responses in vivo, thus having a major impact on patient prognosis. We have previously demonstrated that the presence of calreticulin on the surface of malignant blasts is a positive prognostic biomarker for patients with acute myeloid leukemia (AML). Calreticulin exposure not only correlated with enhanced T-cell-dependent antitumor immunity in this setting but also affected the number of circulating natural killer (NK) cells upon restoration of normal hematopoiesis. Here, we report that calreticulin exposure on malignant blasts is associated with enhanced NK cell cytotoxic and secretory functions, both in AML patients and in vivo in mice. The ability of calreticulin to stimulate NK-cells relies on CD11c+CD14high cells that, upon exposure to CRT, express higher levels of IL-15Rα, maturation markers (CD86 and HLA- DR) and CCR7. CRT exposure on malignant blasts also correlates with the upregulation of genes coding for type I interferon. This suggests that CD11c+CD14high cells have increased capacity to migrate to secondary lymphoid organs, where can efficiently deliver stimulatory signals (IL-15Rα/IL- 15) to NK cells. These findings delineate a multipronged, clinically relevant mechanism whereby surface-exposed calreticulin favors NK-cell activation in AML patients.Disclosure InformationI. Truxova: None. L. Kasikova: None. C. Salek: None. M. Hensler: None. D. Lysak: None. P. Holicek: None. P. Bilkova: None. M. Holubova: None. X. Chen: None. R. Mikyskova: None. M. Reinis: None. M. Kovar: None. B. Tomalova: None. J.P. Kline: None. L. Galluzzi: None. R. Spisek: None. J. Fucikova: None.

scholarly journals Extracellular Vesicles: A Possible Link between HIV and Alzheimer’s Disease-Like Pathology in HIV Subjects?

Cells ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 968 ◽  
Author(s):  
Sunitha Kodidela ◽  
Kelli Gerth ◽  
Sanjana Haque ◽  
Yuqing Gong ◽  
Saifudeen Ismael ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Extracellular Vesicles ◽  
Treatment Strategies ◽  
Progressive Dementia ◽  
Hiv Patients ◽  
Age Related ◽  
Infected Cells ◽  
New Treatment

The longevity of people with HIV/AIDS has been prolonged with the use of antiretroviral therapy (ART). The age-related complications, especially cognitive deficits, rise as HIV patients live longer. Deposition of beta-amyloid (Aβ), a hallmark of Alzheimer’s disease (AD), has been observed in subjects with HIV-associated neurocognitive disorders (HAND). Various mechanisms such as neuroinflammation induced by HIV proteins (e.g., Tat, gp120, Nef), excitotoxicity, oxidative stress, and the use of ART contribute to the deposition of Aβ, leading to dementia. However, progressive dementia in older subjects with HIV might be due to HAND, AD, or both. Recently, extracellular vesicles (EVs)/exosomes, have gained recognition for their importance in understanding the pathology of both HAND and AD. EVs can serve as a possible link between HIV and AD, due to their ability to package and transport the toxic proteins implicated in both AD and HIV (Aβ/tau and gp120/tat, respectively). Given that Aß is also elevated in neuron-derived exosomes isolated from the plasma of HIV patients, it is reasonable to suggest that neuron-to-neuron exosomal transport of Aβ and tau also contributes to AD-like pathology in HIV-infected subjects. Therefore, exploring exosomal contents is likely to help distinguish HAND from AD. However, future prospective clinical studies need to be conducted to compare the exosomal contents in the plasma of HIV subjects with and without HAND as well as those with and without AD. This would help to find new markers and develop new treatment strategies to treat AD in HIV-positive subjects. This review presents comprehensive literatures on the mechanisms contributing to Aβ deposition in HIV-infected cells, the role of EVs in the propagation of Aβ in AD, the possible role of EVs in HIV-induced AD-like pathology, and finally, possible therapeutic targets or molecules to treat HIV subjects with AD.

scholarly journals Galvanic current activates the NLRP3 inflammasome to promote type I collagen production in tendon

2021 ◽  
Author(s):  
Alejandro Peñín-Franch ◽  
José Antonio García-Vidal ◽  
Carlos Manuel Martínez ◽  
Pilar Escolar-Reina ◽  
Ana I.Gómez ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Type I Collagen ◽  
Type I ◽  
Degenerative Diseases ◽  
Galvanic Current ◽  
Beneficial Effects ◽  
Novel Treatment ◽  
Tissue Healing ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

ABSTRACTThe NLRP3 inflammasome coordinates inflammation in response to different pathogen- and damage-associated molecular patterns, being implicated in different infectious, chronic inflammatory, metabolic and degenerative diseases. In chronic tendinopathies lesions, different non-resolving mechanisms produce a degenerative condition that impairs tissue healing, complicating their clinical management. Percutaneous needle electrolysis consist in the application of a galvanic current and is emerging as a novel treatment for tendinopathies. Here we found that galvanic current activates the NLRP3 inflammasome and the induction of an inflammatory response promoting a collagen-mediated regeneration of the tendon. This study establish the molecular mechanism of percutaneous electrolysis for the treatment of chronic lesions and the beneficial effects of an induced inflammasome-related response.

scholarly journals SARS-CoV-2 non-structural protein 1 inhibits the interferon response by causing depletion of key host signaling factors.

2021 ◽  
Author(s):  
Anil Kumar ◽  
Ray Ishida ◽  
Tania Strilets ◽  
Jamie Cole ◽  
Joaquin Lopez-Orozco ◽  
...  
Keyword(s):  
Causative Agent ◽  
Interferon Response ◽  
Type I ◽  
Structural Protein ◽  
Type I Ifns ◽  
Rapid Spread ◽  
Host Signaling ◽  
Infected Cells ◽  
Serious Disease ◽  
Taste And Smell

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic. While previous studies have shown that several SARS-CoV-2 proteins can antagonize the interferon (IFN) response, some of the mechanisms by which they do so are not well understood. In this study, we describe two novel mechanisms by which SARS-CoV-2 blocks the IFN pathway. Type I IFNs and IFN-stimulated genes (ISGs) were poorly induced during SARS-CoV-2 infection and once infection was established, cells were highly resistant to ectopic induction of IFNs and ISGs. Levels of two key IFN signaling pathway components, Tyk2 and STAT2 were significantly lower in SARS-CoV-2 infected cells. Expression of non-structural protein 1 (NSP1) or nucleocapsid in the absence of other viral proteins was sufficient to block IFN induction but only NSP1 was able to inhibit IFN signaling. Mapping studies suggest that NSP1 prevents IFN induction in part by blocking IRF3 phosphorylation. In addition, NSP1-induced depletion of Tyk2 and STAT2 dampened ISG induction. Together, our study provides new insights into how SARS-CoV-2 successfully evades the IFN system to establish infection. Importance SARS-CoV-2 is the causative agent of COVID-19, a serious disease that can have myriad of symptoms from loss of taste and smell to pneumonia and hypercoagulation. The rapid spread of SARS-CoV-2 can be attributed in part to asymptomatic transmission, where infected individuals shed large amounts of virus before the onset of disease. This is likely due to the ability of SARS-CoV-2 to effectively suppress the innate immune system, including the IFN response. Indeed, we show that the IFN response is efficiently blocked during SARS-CoV-2 infection, a process that is mediated in large part by non-structural protein 1 and nucleocapsid. Our study provides new insights on how SARS-CoV-2 evades the IFN response to successfully establish infection. These findings should be considered for the development and administration of therapeutics against SARS-CoV-2.

Stimulator of Interferon Genes Signaling Pathway and its Role in Anti-tumor Immune Therapy

2020 ◽  
Vol 26 (26) ◽  
pp. 3085-3095 ◽  
Author(s):  
Yuanjin Gong ◽  
Chang Chang ◽  
Xi Liu ◽  
Yan He ◽  
Yiqi Wu ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Immune Therapy ◽  
Signal Transduction Pathway ◽  
The Body ◽  
Innate Immune ◽  
Type I ◽  
Innate Immune Signaling ◽  
Critical Problems ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Stimulator of interferon genes is an important innate immune signaling molecule in the body and is involved in the innate immune signal transduction pathway induced by pathogen-associated molecular patterns or damage-associated molecular patterns. Stimulator of interferon genes promotes the production of type I interferon and thus plays an important role in the innate immune response to infection. In addition, according to a recent study, the stimulator of interferon genes pathway also contributes to anti-inflammatory and anti-tumor reactions. In this paper, current researches on the Stimulator of interferon genes signaling pathway and its relationship with tumor immunity are reviewed. Meanwhile, a series of critical problems to be addressed in subsequent studies are discussed as well.

scholarly journals Investigating Functional Roles for Positive Feedback and Cellular Heterogeneity in the Type I Interferon Response to Viral Infection

Viruses ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 517 ◽  
Author(s):  
Sivan Leviyang ◽  
Igor Griva
Keyword(s):  
Mathematical Model ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Experimental Studies ◽  
Cellular Heterogeneity ◽  
Interferon Response ◽  
Type I ◽  
Type I Ifn ◽  
Functional Roles ◽  
Infected Cells

Secretion of type I interferons (IFN) by infected cells mediates protection against many viruses, but prolonged or excessive type I IFN secretion can lead to immune pathology. A proper type I IFN response must therefore maintain a balance between protection and excessive IFN secretion. It has been widely noted that the type I IFN response is driven by positive feedback and is heterogeneous, with only a fraction of infected cells upregulating IFN expression even in clonal cell lines, but the functional roles of feedback and heterogeneity in balancing protection and excessive IFN secretion are not clear. To investigate the functional roles for feedback and heterogeneity, we constructed a mathematical model coupling IFN and viral dynamics that extends existing mathematical models by accounting for feedback and heterogeneity. We fit our model to five existing datasets, reflecting different experimental systems. Fitting across datasets allowed us to compare the IFN response across the systems and suggested different signatures of feedback and heterogeneity in the different systems. Further, through numerical experiments, we generated hypotheses of functional roles for IFN feedback and heterogeneity consistent with our mathematical model. We hypothesize an inherent tradeoff in the IFN response: a positive feedback loop prevents excessive IFN secretion, but also makes the IFN response vulnerable to viral antagonism. We hypothesize that cellular heterogeneity of the IFN response functions to protect the feedback loop from viral antagonism. Verification of our hypotheses will require further experimental studies. Our work provides a basis for analyzing the type I IFN response across systems.

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