SARS-CoV-2 induces inflammasome-dependent pyroptosis and downmodulation of HLA-DR in human monocytes

AbstractInfection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with leukopenia and uncontrolled inflammatory response in critically ill patients. A better comprehension of SARS-CoV-2-induced monocyte death is essential for the identification of therapies capable to control the hyper-inflammation and reduce viral replication in patients with COVID-19. Here, we show that SARS-CoV-2 induces inflammasome activation and cell death by pyroptosis in human monocytes, experimentally infected and from patients under intensive care. Pyroptosis was dependent on caspase-1 engagement, prior to IL-1ß production and inflammatory cell death. Monocytes exposed to SARS-CoV-2 downregulate HLA-DR, suggesting a potential limitation to orchestrate the immune response. Our results originally describe mechanisms by which monocytes, a central cellular component recruited from peripheral blood to respiratory tract, succumb to control severe 2019 coronavirus disease (COVID-19).Author summarySince its emergence in China in late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused thousands of deaths worldwide. Currently, the number of individuals infected with SARS-CoV-2 and in need of antiviral, anti-inflammatory, anticoagulant and more invasive treatments has overwhelmed the health systems worldwide. In our study, we found that SARS-CoV-2 is capable of inducing inflammatory cell death in human monocytes, one of the main cell types responsible for anti-SARS-CoV-2 immune response. As a consequence of this intracellular inflammatory mechanism (inflammasome engagement), an exacerbated production of inflammatory mediators occurs. The infection also decreases the expression of HLA-DR in monocytes, a molecule related to the orchestration of the immune response in case of viral infections. We also demonstrated that the HIV-1 protease inhibitor, atazanavir (ATV), prevented the uncontrolled inflammatory response, cell death and reduction in HLA-DR expression in SARS-CoV-2-infected monocytes. Our study provides relevant information on the effects of SARS-CoV-2 infection on human monocytes, as well as on the effect of ATV in preventing these pathological effects on the host.

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RBM15-mediated N6-methyladenosine modification affects COVID-19 severity by regulating the expression of multitarget genes

Cell Death and Disease ◽

10.1038/s41419-021-04012-z ◽

2021 ◽

Vol 12 (8) ◽

Author(s):

Yuting Meng ◽

Qiong Zhang ◽

Kaihang Wang ◽

Xujun Zhang ◽

Rongwei Yang ◽

...

Keyword(s):

Immune Response ◽

Cell Death ◽

Severe Acute Respiratory Syndrome ◽

Programmed Cell Death ◽

Inflammatory Response ◽

Disease Severity ◽

Biological Processes ◽

Underlying Mechanisms ◽

Microarray Analyses

AbstractSevere coronavirus disease 2019 (COVID-19) is characterized by symptoms of lymphopenia and multiorgan damage, but the underlying mechanisms remain unclear. To explore the function of N6-methyladenosine (m6A) modifications in COVID-19, we performed microarray analyses to comprehensively characterize the m6A epitranscriptome. The results revealed distinct global m6A profiles in severe and mild COVID-19 patients. Programmed cell death and inflammatory response were the major biological processes modulated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Further, RBM15, a major m6A methyltransferase, was significantly elevated and positively correlated with disease severity. Silencing RBM15 drastically reduced lymphocyte death in vitro. Knockdown of RBM15 remarkably suppressed the expression levels of multitarget genes related to programmed cell death and inflammatory response. This study shows that SARS-CoV-2 infection alters the m6A epitranscriptome of lymphocytes, particularly in the case of severe patients. RBM15 regulated host immune response to SARS-CoV-2 by elevating m6A modifications of multitarget genes. These findings indicate that RBM15 can serve as a target for the treatment of COVID-19.

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ZBP1 promotes LPS-induced cell death and IL-1β release via RHIM-mediated interactions with RIPK1

Nature Communications ◽

10.1038/s41467-020-20357-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Hayley I. Muendlein ◽

Wilson M. Connolly ◽

Zoie Magri ◽

Irina Smirnova ◽

Vladimir Ilyukha ◽

...

Keyword(s):

Immune Response ◽

Cell Death ◽

Complex Formation ◽

Complex I ◽

Yersinia Pseudotuberculosis ◽

Caspase 8 ◽

Inflammasome Activation ◽

Inflammatory Signaling ◽

Complex Ii ◽

Dependent Model

AbstractInflammation and cell death are closely linked arms of the host immune response to infection, which when carefully balanced ensure host survival. One example of this balance is the tightly regulated transition from TNFR1-associated pro-inflammatory complex I to pro-death complex II. By contrast, here we show that a TRIF-dependent complex containing FADD, RIPK1 and caspase-8 (that we have termed the TRIFosome) mediates cell death in response to Yersinia pseudotuberculosis and LPS. Furthermore, we show that constitutive binding between ZBP1 and RIPK1 is essential for the initiation of TRIFosome interactions, caspase-8-mediated cell death and inflammasome activation, thus positioning ZBP1 as an effector of cell death in the context of bacterial blockade of pro-inflammatory signaling. Additionally, our findings offer an alternative to the TNFR1-dependent model of complex II assembly, by demonstrating pro-death complex formation reliant on TRIF signaling.

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Evasion of Necroptosis and Inflammasome Activation Promotes Myeloid Leukemogenesis

Blood ◽

10.1182/blood.v128.22.2856.2856 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2856-2856

Author(s):

Ulrike Höckendorf ◽

Yabal Monica ◽

Christian Peschel ◽

Philipp J. Jost

Keyword(s):

Stem Cells ◽

Cell Death ◽

Hematopoietic Stem Cells ◽

Progenitor Cells ◽

Protein Level ◽

Inflammatory Cell ◽

Leukemic Cells ◽

Inflammasome Activation ◽

Short Term ◽

Hematopoietic Stem

Abstract Acute myeloid leukemia (AML) is a heterogeneous group of hematopoietic neoplasms driven partly by the loss of differentiation and theblockade of cell death. AML is sustained by leukemia-initiating cells (LICs) that arise from pre-leukemic hematopoietic stem and progenitor cells (HSPCs) that carry genetic alterations being selected for during leukemogenesis. The resistance of LICs to standard chemotherapies presents a major clinical challenge as they eventually cause disease relapse and death. Understanding the mechanisms of LIC resistance to undergoing cell death is therefore critical for a curative therapy of AML. While the regulatory factors that maintain HSPC proliferation and differentiation under normal conditions are well understood, significantly less is known about how LIC fate is regulated. As many hematopoietic disorders are characterized by the overproduction of pro-inflammatory cytokines, we hypothesized that necroptosis controlled cytokine secretion and inflammatory cell death might influence AML development. We therefore addressed the role of MLKL and XIAP in AML and tested whether deletion of Mlkl or Xiap would affect disease progression. Here we show that MLKL limits oncogene-mediated leukemogenesis by promoting the inflammatory cell death of common myeloid progenitors (CMPs) and short-term hematopoietic stem cells (HSCs) in experimental mice. Upon oncogenic stress MLKL-dependent necroptosis and subsequent inflammasome activation were triggered, promoting the production of IL-1β, a potent stimulator of HSPC differentiation and maturation, thus, suppressing the emergence of LICs and limiting leukemogenesis. In a murine bone marrow transplantation model of AML the absence of MLKL accelerated AML development significantly. The enhanced disease was due to the expansion of common myeloid progenitors (CMPs) and short-term hematopoietic stem cells (ST-HSCs), being the cellular compartments to contain LICs. The survival advantage of Mlkl-/- HSPCs became apparent in colony-forming assays and liquid cultures specifically within the CMP and ST-HSC compartments. Sorted ST-HSCs from Mlkl-/- produced more GEMM colonies than WT, the colony type harboring the multipotential myeloid progenitor cells, and both ST-HSCs and CMPs retained significantly more lineage-negative cells in liquid culture. In addition, Mlkl-/- colonies showed a reduction in propidium iodide (PI)-positive dead cells compared with WT colonies. Importantly, WT cells showed caspase activation and produced substantial amounts of the inflammatory cytokine IL-1β which was severely blunted by Mlkl deficiency. We also observed reduced expression of MLKL in leukemic cells on both mRNA and protein level, implying that suppression of cell death was beneficial for the survival of LICs. In contrast, deletion of Xiap did not alter survival or differentiation of leukemic cells when compared with WT cells. Furthermore, XIAP was not differentially expressed on mRNA or protein level compared with WT, indicating that XIAP does not play a critical role in leukemogenesis. In agreement with the murine data, gene expression analysis from primary leukemia cells from two large patient cohorts newly diagnosed with AML showed significantly lower expression of MLKL, but not XIAP, in a variety of AML subtypes compared to healthy controls. Overall, our data demonstrate a key role for MLKL-mediated cell death and activation of the inflammasome in AML and represents a novel tumor-suppressive mechanism. Disclosures Peschel: MophoSys: Honoraria.

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MiR-146b Mediates Endotoxin Tolerance in Human Phagocytes

Mediators of Inflammation ◽

10.1155/2015/145305 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 12

Author(s):

Tiziana Ada Renzi ◽

Marcello Rubino ◽

Laura Gornati ◽

Cecilia Garlanda ◽

Massimo Locati ◽

...

Keyword(s):

Immune Response ◽

Immune System ◽

Inflammatory Response ◽

Innate Immune Response ◽

Endotoxin Tolerance ◽

Innate Immune ◽

Human Monocytes ◽

Key Factors ◽

Tlr Signaling ◽

Tolerant State

A proper regulation of the innate immune response is fundamental to keep the immune system in check and avoid a chronic status of inflammation. As they act as negative modulators of TLR signaling pathways, miRNAs have been recently involved in the control of the inflammatory response. However, their role in the context of endotoxin tolerance is just beginning to be explored. We here show that miR-146b is upregulated in human monocytes tolerized by LPS, IL-10, or TGFβpriming and demonstrate that its transcription is driven by STAT3 and RUNX3, key factors downstream of IL-10 and TGFβsignaling. Our study also found that IFNγ, known to revert LPS tolerant state, inhibits miR-146b expression. Finally, we provide evidence that miR-146b levels have a profound effect on the tolerant state, thus candidating miR-146b as a molecular mediator of endotoxin tolerance.

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New insights in caspase-11 functions in noncanonical inflammasome signalling

Inflammasome ◽

10.2478/infl-2014-0001 ◽

2014 ◽

Vol 1 (1) ◽

Author(s):

Mélanie Bodnar ◽

Virginie Petrilli

Keyword(s):

Cell Death ◽

Inflammatory Cell ◽

Protein Complexes ◽

Inflammasome Activation ◽

Gram Negative Bacteria ◽

Nucleotide Binding Domain ◽

Gram Negative ◽

Caspase 1 ◽

Nlrp3 Inflammasome Activation ◽

Dependent Pathway

AbstractInflammasomes are multi-protein complexes that play a crucial role in innate immunity. They are assembled by cytosolic sensors of the Nucleotide-binding domain and Leucine-rich repeat containing Receptor (NLR) and PYrin and HIN (PYHIN) domain-containing protein families upon sensing various pathogens and danger signals. Inflammasome formation culminates in caspase-1 activation, which causes the cleavage of pro-IL-1β and pro- IL-18 into active cytokines; this eventually results in the induction of an inflammatory cell death called pyroptosis. Recent data using Gram-negative bacteria suggests a role for caspase-11 not only in NLRP3 inflammasome activation but also in a caspase-1- and inflammasome-independent cell death. This novel caspase-11-dependent pathway is critical to control infection by Gram-negative bacteria and has been named the noncanonical inflammasome.

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Hyperinflammation and Immune Response Generation in COVID-19

NeuroImmunoModulation ◽

10.1159/000513198 ◽

2020 ◽

pp. 1-7

Author(s):

Kamla Prasad Mishra ◽

Ajay Kumar Singh ◽

Shashi Bala Singh

Keyword(s):

Immune Response ◽

Severe Acute Respiratory Syndrome ◽

Inflammatory Response ◽

Disease Severity ◽

Human Body ◽

Scientific Community ◽

The Other ◽

Complement Proteins ◽

Cytokines And Chemokines ◽

Cell Mediated Immune Response

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) pandemic has affected millions of people worldwide. The pathophysiology of this virus is not very clearly known, thus, enormous efforts are being made by the scientific community to delineate its evading mechanism. In this review, we have summarized the hyperinflammation and humoral and cell-mediated immune response generated in human body after infection with the SARS-CoV-2 virus. The inflammatory response generated after infection by increased proinflammatory cytokines and chemokines, and complement proteins activation may likely contribute to disease severity. We also discussed the other factors that may affect immunity and could be important comorbidities in the disease severity and outcome.

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NLRP3 deletion protects from hyperoxia-induced acute lung injury

AJP Cell Physiology ◽

10.1152/ajpcell.00086.2013 ◽

2013 ◽

Vol 305 (2) ◽

pp. C182-C189 ◽

Cited By ~ 94

Author(s):

Jutaro Fukumoto ◽

Itsuko Fukumoto ◽

Prasanna Tamarapu Parthasarathy ◽

Ruan Cox ◽

Bao Huynh ◽

...

Keyword(s):

Cell Death ◽

Acute Lung Injury ◽

Epithelial Cell ◽

Lung Injury ◽

Inflammatory Response ◽

Lung Epithelial Cell ◽

Inflammasome Activation ◽

Nlrp3 Gene ◽

Lung Epithelial ◽

Epithelial Cell Death

Inspiration of a high concentration of oxygen, a therapy for acute lung injury (ALI), could unexpectedly lead to reactive oxygen species (ROS) production and hyperoxia-induced acute lung injury (HALI). Nucleotide-binding domain and leucine-rich repeat PYD-containing protein 3 (NLRP3) senses the ROS, triggering inflammasome activation and interleukin-1β (IL-1β) production and secretion. However, the role of NLRP3 inflammasome in HALI is unclear. The main aim of this study is to determine the effect of NLRP3 gene deletion on inflammatory response and lung epithelial cell death. Wild-type (WT) and NLRP3−/− mice were exposed to 100% O2 for 48–72 h. Bronchoalveolar lavage fluid and lung tissues were examined for proinflammatory cytokine production and lung inflammation. Hyperoxia-induced lung pathological score was suppressed in NLRP3−/− mice compared with WT mice. Hyperoxia-induced recruitment of inflammatory cells and elevation of IL-1β, TNFα, macrophage inflammatory protein-2, and monocyte chemoattractant protein-1 were attenuated in NLRP3−/− mice. NLRP3 deletion decreased lung epithelial cell death and caspase-3 levels and a suppressed NF-κB levels compared with WT controls. Taken together, this research demonstrates for the first time that NLRP3-deficient mice have suppressed inflammatory response and blunted lung epithelial cell apoptosis to HALI.

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Myosin 1f-mediated activation of microglia contributes to the photoreceptor degeneration in a mouse model of retinal detachment

Cell Death and Disease ◽

10.1038/s41419-021-03983-3 ◽

2021 ◽

Vol 12 (10) ◽

Author(s):

Yimin Wang ◽

Xiaohuan Zhao ◽

Min Gao ◽

Xiaoling Wan ◽

Yinong Guo ◽

...

Keyword(s):

Immune Response ◽

Cell Death ◽

Visual Acuity ◽

Retinal Detachment ◽

Inflammatory Response ◽

Mouse Model ◽

Vision Loss ◽

Photoreceptor Degeneration ◽

Retinal Injury ◽

Photoreceptor Death

AbstractPhotoreceptor death and neurodegeneration is the leading cause of irreversible vision loss. The inflammatory response of microglia plays an important role in the process of neurodegeneration. In this study, we chose retinal detachment as the model of photoreceptor degeneration. We found Myosin 1f was upregulated after retinal detachment, and it was specifically expressed in microglia. Deficiency of myosin 1f protected against photoreceptor apoptosis by inhibiting microglia activation. The elimination of microglia can abolish the protective effect of myosin 1f deficiency. After stimulation by LPS, microglia with myosin 1f deficiency showed downregulation of the MAPK and AKT pathways. Our results demonstrated that myosin 1f plays a crucial role in microglia-induced neuroinflammation after retinal injury and photoreceptor degeneration by regulating two classic inflammatory pathways and thereby decreasing the expression of inflammatory cytokines. Knockout of myosin 1f reduces the intensity of the immune response and prevents cell death of photoreceptor, suggesting that myosin 1f can be inhibited to prevent a decline in visual acuity after retinal detachment.

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SARS-CoV-2 infects blood monocytes to activate NLRP3 and AIM2 inflammasomes, pyroptosis and cytokine release

10.21203/rs.3.rs-153628/v1 ◽

2021 ◽

Author(s):

Caroline Junqueira ◽

Ângela Crespo ◽

Shahin Ranjbar ◽

Mercedes Lewandrowski ◽

Jacob Ingber ◽

...

Keyword(s):

Cell Death ◽

Inflammatory Cell ◽

Infectious Virus ◽

Multiorgan Failure ◽

Inflammasome Activation ◽

Invasive Infection ◽

Blood Monocytes ◽

Fluorescent Reporter ◽

Caspase 1 ◽

Monocytes And Macrophages

Abstract SARS-CoV-2 causes acute respiratory distress that can progress to multiorgan failure and death in a minority of patients. Although severe COVID-19 disease is linked to exuberant inflammation, how SARS-CoV-2 triggers inflammation is not understood. Monocytes and macrophages are sentinel immune cells in the blood and tissue, respectively, that sense invasive infection to form inflammasomes that activate caspase-1 and gasdermin D (GSDMD) pores, leading to inflammatory death (pyroptosis) and processing and release of IL-1 family cytokines, potent inflammatory mediators. Here we show that expression quantitative trait loci (eQTLs) linked to higher GSDMD expression increase the risk of severe COVID-19 disease (odds ratio, 1.3, p<0.005). We find that about 10% of blood monocytes in COVID-19 patients are infected with SARS-CoV-2. Monocyte infection depends on viral antibody opsonization and uptake of opsonized virus by the Fc receptor CD16. After uptake, SARS-CoV-2 begins to replicate in monocytes, as evidenced by detection of double-stranded RNA and subgenomic RNA and expression of a fluorescent reporter gene. However, infection is aborted, and infectious virus is not detected in infected monocyte supernatants or patient plasma. Instead, infected cells undergo inflammatory cell death (pyroptosis) mediated by activation of the NLRP3 and AIM2 inflammasomes, caspase-1 and GSDMD. Moreover, tissue-resident macrophages, but not infected epithelial cells, from COVID-19 lung autopsy specimens showed evidence of inflammasome activation. These findings taken together suggest that antibody-mediated SARS-CoV-2 infection of monocytes/macrophages triggers inflammatory cell death that aborts production of infectious virus but causes systemic inflammation that contributes to severe COVID-19 disease pathogenesis.

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MODIFICATION OF IMMUNOCYTES VIABLE PARAMETERS IN CHILDREN ASSOCIATED WITH COMBINED EXPOSURE TO CHEMICAL TECHNOGENIC AND EXTREME CLIMATIC FACTORS

Health Risk Analysis ◽

10.21668/health.risk/2021.3.12 ◽

2021 ◽

pp. 129-130

Author(s):

I.N. Alikina ◽

◽

O.V. Dolgikh ◽

Keyword(s):

Cell Death ◽

Viral Infections ◽

Climatic Factors ◽

Reference Group ◽

Test Group ◽

Climatic Conditions ◽

Polar Regions ◽

Combined Exposure ◽

Hla Dr ◽

Significant Difference

The article dwells on results obtained via immunologic parameters of immunocytes death among children living and attending educational establishments in regions beyond the Polar circle where industry was developing rather intensely. Our research goal was to examine early disorders in immunologic profile as per immunocytes death among children living in Polar Regions under combined exposure to adverse chemical technogenic and extreme climatic factors. 75 children took part in the research (a test group); they lived and attended educational establishments in regions beyond the Po- lar circle where industry was developing rather intensely. Benzpyrene is a priority chemical exogenous factor in this region and a cli- matic one is extremely low temperature in winter (average temperature is -33,8 оС in this season). A reference group was made up of children (n = 35) who lived and attended educational facilities in Polar Regions where there was no exposure to technogenic chemical factors. The authors analyzed several immunogram parameters including CD3+CD95+, Annexin-V presenting cells, TNFRα, CD3+HLA-DR+, bax and p53. Cell death parameters were examined with fluorescent analysis via flow cytometry. Also, the authors assessed specific sensitivity of IgG to benzpyrene via allergosorbent testing with enzyme marker. The research revealed hyperexpression of lymphocytes-cellular profile parameters in children from the test group in comparison with the reference one. They had 1.4 times higher expression of immunocytes stained with AnnexinV and a num- ber of cells stained with PI (Propidium Iodide) was considerably higher than a number of cells stained with AnnexinV as well as the same parameters in the reference group(by 1.5 times) thus indicating that immunocytes predominantly die due to necrosis. There was hyperexpression of HLA-DR+ receptor on lymphocytes (both its relative and absolute quantity in 12.4–13.7 % children). Expression of CD95+ receptor (a membrane marker of immunocytes apoptosis) was 1.3 and 1.4 times higher (rela- tive and absolute value accordingly).The authors detected an authentically elevated contents of tumor necrosis factor recep- tor (TNFR) as well as intracellular anti-tumor antigen p53, and antiapoptotic protein bax that were by 1.5, 1.2 and 1.3 times higher accordingly (р<0.05) against the reference group. There was a significant difference in production of IgG specific to benzpyrene in children from the test group since its expression was 2.4 times higher than in children from the reference group (р<0.05). The authors detected elevated risks of excessive expression both for membrane factors of cellular death TNFR (RR = 12.17), CD3+СD95+(RR = 5.42), HLA-DR+ (RR = 4.80) that were apoptosis affectors and for intracellular transcription factors bax (RR = 4.55) and p53 (RR = 3.71) that modulated apoptogenic signals. This risk was associated with combined exposure to chemical tehcnigenic and extreme climatic conditions. It wasestablished that children living in the Polar Regions under combined exposure to chemical technogenic and ex- treme climatic conditions had imbalance in the immune status that became apparent via excessive expression of membrane (HLA-DR+, CD95+, TNFR) and intracellular (p53, bax) parameters with cell death program shifting towards necrosis (as opposed to the reference group that was exposed only to extreme climatic factors). These parameters indicate there is im- mune deficiency and a significant probability of viral infections and their complications.

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