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1.
Sci Rep ; 11(1): 24432, 2021 12 24.
Article in English | MEDLINE | ID: covidwho-1585772

ABSTRACT

Despite the initial success of some drugs and vaccines targeting COVID-19, understanding the mechanism underlying SARS-CoV-2 disease pathogenesis remains crucial for the development of further approaches to treatment. Some patients with severe Covid-19 experience a cytokine storm and display evidence of inflammasome activation leading to increased levels of IL-1ß and IL-18; however, other reports have suggested reduced inflammatory responses to Sars-Cov-2. In this study we have examined the effects of the Sars-Cov-2 envelope (E) protein, a virulence factor in coronaviruses, on inflammasome activation and pulmonary inflammation. In cultured macrophages the E protein suppressed inflammasome priming and NLRP3 inflammasome activation. Similarly, in mice transfected with E protein and treated with poly(I:C) to simulate the effects of viral RNA, the E protein, in an NLRP3-dependent fashion, reduced expression of pro-IL-1ß, levels of IL-1ß and IL-18 in broncho-alveolar lavage fluid, and macrophage infiltration in the lung. To simulate the effects of more advanced infection, macrophages were treated with both LPS and poly(I:C). In this setting the E protein increased NLRP3 inflammasome activation in both murine and human macrophages. Thus, the Sars-Cov-2 E protein may initially suppress the host NLRP3 inflammasome response to viral RNA while potentially increasing NLRP3 inflammasome responses in the later stages of infection. Targeting the Sars-Cov-2 E protein especially in the early stages of infection may represent a novel approach to Covid-19 therapy.


Subject(s)
Coronavirus Envelope Proteins/metabolism , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , SARS-CoV-2/metabolism , Animals , Bronchoalveolar Lavage Fluid/chemistry , COVID-19/pathology , COVID-19/virology , Coronavirus Envelope Proteins/genetics , Down-Regulation/drug effects , Endoplasmic Reticulum Stress , Humans , Inflammasomes/drug effects , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Janus Kinases/genetics , Janus Kinases/metabolism , Lipopolysaccharides/pharmacology , Macrophages/cytology , Macrophages/drug effects , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , NLR Family, Pyrin Domain-Containing 3 Protein/deficiency , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Poly I-C/pharmacology , RNA, Viral/metabolism , SARS-CoV-2/drug effects , SARS-CoV-2/isolation & purification
3.
Med Hypotheses ; 146: 110396, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-1386308

ABSTRACT

We have reviewed a considerable amount of recent scientific papers relating inflammation caused by air pollution with chronic and severe medical conditions. Furthermore, there are evidences relating organ inflammation caused by not only outdoor long-term but also short-term inhaled radioisotopes contained in high polluted air or in household natural radioactive background aerosols, in addition to SARS-COV-2 attached to bioaerosols, which are related with a worst evolution of severe acute respiratory syndrome patients. Reactive oxygen species (ROS) production induced by the interaction with environmental ionizing radiation contained in pollution is pointed out as a critical mechanism that predispose mainly to elder population, but not excluding young subjects, presenting previous chronic conditions of lung inflammation or neuroinflammation, which can lead to the most serious consequences.


Subject(s)
Air Pollution, Radioactive/adverse effects , COVID-19/etiology , Climate Change , Inflammation/etiology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , SARS-CoV-2/pathogenicity , Aerosols , Air Microbiology , COVID-19/mortality , Causality , Humans , Inflammasomes/metabolism , Inflammasomes/radiation effects , Models, Biological , Nervous System Diseases/etiology , Pandemics , Particle Size , Particulate Matter/adverse effects , Pneumonia/etiology
4.
Viruses ; 13(8)2021 08 16.
Article in English | MEDLINE | ID: covidwho-1376993

ABSTRACT

Given the impact of pandemics due to viruses of bat origin, there is increasing interest in comparative investigation into the differences between bat and human immune responses. The practice of comparative biology can be enhanced by computational methods used for dynamic knowledge representation to visualize and interrogate the putative differences between the two systems. We present an agent based model that encompasses and bridges differences between bat and human responses to viral infection: the comparative biology immune agent based model, or CBIABM. The CBIABM examines differences in innate immune mechanisms between bats and humans, specifically regarding inflammasome activity and type 1 interferon dynamics, in terms of tolerance to viral infection. Simulation experiments with the CBIABM demonstrate the efficacy of bat-related features in conferring viral tolerance and also suggest a crucial role for endothelial inflammasome activity as a mechanism for bat systemic viral tolerance and affecting the severity of disease in human viral infections. We hope that this initial study will inspire additional comparative modeling projects to link, compare, and contrast immunological functions shared across different species, and in so doing, provide insight and aid in preparation for future viral pandemics of zoonotic origin.


Subject(s)
Chiroptera/immunology , Immunity, Innate , Virus Diseases/immunology , Virus Diseases/veterinary , Animals , Chiroptera/virology , Computer Simulation , Endothelium/physiology , Humans , Inflammasomes/immunology , Inflammasomes/metabolism , Interferon Type I/immunology , Interferon Type I/metabolism , Severity of Illness Index , Stress, Physiological , Viral Zoonoses , Virus Diseases/virology , Virus Physiological Phenomena , Virus Shedding
5.
Cell Rep ; 36(8): 109614, 2021 08 24.
Article in English | MEDLINE | ID: covidwho-1370458

ABSTRACT

Zoonotic pathogens, such as COVID-19, reside in animal hosts before jumping species to infect humans. The Carnivora, like mink, carry many zoonoses, yet how diversity in host immune genes across species affect pathogen carriage is poorly understood. Here, we describe a progressive evolutionary downregulation of pathogen-sensing inflammasome pathways in Carnivora. This includes the loss of nucleotide-oligomerization domain leucine-rich repeat receptors (NLRs), acquisition of a unique caspase-1/-4 effector fusion protein that processes gasdermin D pore formation without inducing rapid lytic cell death, and the formation of a caspase-8 containing inflammasome that inefficiently processes interleukin-1ß. Inflammasomes regulate gut immunity, but the carnivorous diet has antimicrobial properties that could compensate for the loss of these immune pathways. We speculate that the consequences of systemic inflammasome downregulation, however, can impair host sensing of specific pathogens such that they can reside undetected in the Carnivora.


Subject(s)
Carnivora/metabolism , Evolution, Molecular , Inflammasomes/metabolism , Zoonoses/pathology , Animals , Caspase 1/genetics , Caspase 1/metabolism , Caspase 8/metabolism , Caspases, Initiator/genetics , Caspases, Initiator/metabolism , Cell Death , Cell Line , Humans , Interleukin-1beta/metabolism , Lipopolysaccharides/pharmacology , Macrophages/cytology , Macrophages/drug effects , Macrophages/metabolism , Mice , Mice, Inbred C57BL , NLR Proteins/genetics , NLR Proteins/metabolism , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Salmonella typhi/pathogenicity , Zoonoses/immunology , Zoonoses/parasitology
6.
Front Immunol ; 12: 683879, 2021.
Article in English | MEDLINE | ID: covidwho-1369666

ABSTRACT

Diseases caused by pathogenic bacteria in animals (e.g., bacterial pneumonia, meningitis and sepsis) and plants (e.g., bacterial wilt, angular spot and canker) lead to high prevalence and mortality, and decomposition of plant leaves, respectively. Melatonin, an endogenous molecule, is highly pleiotropic, and accumulating evidence supports the notion that melatonin's actions in bacterial infection deserve particular attention. Here, we summarize the antibacterial effects of melatonin in vitro, in animals as well as plants, and discuss the potential mechanisms. Melatonin exerts antibacterial activities not only on classic gram-negative and -positive bacteria, but also on members of other bacterial groups, such as Mycobacterium tuberculosis. Protective actions against bacterial infections can occur at different levels. Direct actions of melatonin may occur only at very high concentrations, which is at the borderline of practical applicability. However, various indirect functions comprise activation of hosts' defense mechanisms or, in sepsis, attenuation of bacterially induced inflammation. In plants, its antibacterial functions involve the mitogen-activated protein kinase (MAPK) pathway; in animals, protection by melatonin against bacterially induced damage is associated with inhibition or activation of various signaling pathways, including key regulators such as NF-κB, STAT-1, Nrf2, NLRP3 inflammasome, MAPK and TLR-2/4. Moreover, melatonin can reduce formation of reactive oxygen and nitrogen species (ROS, RNS), promote detoxification and protect mitochondrial damage. Altogether, we propose that melatonin could be an effective approach against various pathogenic bacterial infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Inflammasomes/metabolism , Melatonin/pharmacology , Sepsis/metabolism , Signal Transduction/drug effects , Animals , Humans , Inflammasomes/drug effects , Mitogen-Activated Protein Kinases/drug effects , Mitogen-Activated Protein Kinases/metabolism , NF-kappa B/drug effects , NF-kappa B/metabolism , Plant Leaves , Reactive Oxygen Species , Sepsis/genetics , Sepsis/immunology
7.
Nat Rev Immunol ; 21(11): 694-703, 2021 11.
Article in English | MEDLINE | ID: covidwho-1349668

ABSTRACT

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), results in life-threatening disease in a minority of patients, especially elderly people and those with co-morbidities such as obesity and diabetes. Severe disease is characterized by dysregulated cytokine release, pneumonia and acute lung injury, which can rapidly progress to acute respiratory distress syndrome, disseminated intravascular coagulation, multisystem failure and death. However, a mechanistic understanding of COVID-19 progression remains unclear. Here we review evidence that SARS-CoV-2 directly or indirectly activates inflammasomes, which are large multiprotein assemblies that are broadly responsive to pathogen-associated and stress-associated cellular insults, leading to secretion of the pleiotropic IL-1 family cytokines (IL-1ß and IL-18), and pyroptosis, an inflammatory form of cell death. We further discuss potential mechanisms of inflammasome activation and clinical efforts currently under way to suppress inflammation to prevent or ameliorate severe COVID-19.


Subject(s)
COVID-19/immunology , Inflammasomes/immunology , Animals , COVID-19/pathology , COVID-19/physiopathology , Cytokines/immunology , Humans , Inflammasomes/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Lung/immunology , Lung/pathology , Lung/virology , Phosphate-Binding Proteins/metabolism , Pyroptosis , Respiratory Distress Syndrome/immunology , Respiratory Distress Syndrome/virology , Severity of Illness Index
8.
Nat Commun ; 12(1): 4664, 2021 08 02.
Article in English | MEDLINE | ID: covidwho-1338538

ABSTRACT

Excessive inflammatory responses induced upon SARS-CoV-2 infection are associated with severe symptoms of COVID-19. Inflammasomes activated in response to SARS-CoV-2 infection are also associated with COVID-19 severity. Here, we show a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation to induce hyperinflammation. N protein facilitates maturation of proinflammatory cytokines and induces proinflammatory responses in cultured cells and mice. Mechanistically, N protein interacts directly with NLRP3 protein, promotes the binding of NLRP3 with ASC, and facilitates NLRP3 inflammasome assembly. More importantly, N protein aggravates lung injury, accelerates death in sepsis and acute inflammation mouse models, and promotes IL-1ß and IL-6 activation in mice. Notably, N-induced lung injury and cytokine production are blocked by MCC950 (a specific inhibitor of NLRP3) and Ac-YVAD-cmk (an inhibitor of caspase-1). Therefore, this study reveals a distinct mechanism by which SARS-CoV-2 N protein promotes NLRP3 inflammasome activation and induces excessive inflammatory responses.


Subject(s)
COVID-19/metabolism , Coronavirus Nucleocapsid Proteins/metabolism , Inflammasomes/metabolism , Inflammation/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , SARS-CoV-2/metabolism , Animals , COVID-19/virology , Cells, Cultured , Cytokines/metabolism , HEK293 Cells , Humans , Inflammasomes/genetics , Lung Injury/genetics , Lung Injury/metabolism , Male , Mice, Inbred C57BL , Mice, Knockout , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Phosphoproteins/metabolism , Protein Binding , SARS-CoV-2/physiology , THP-1 Cells
9.
Int J Mol Sci ; 22(15)2021 Jul 24.
Article in English | MEDLINE | ID: covidwho-1325681

ABSTRACT

The outbreak of the coronavirus disease 2019 (COVID-19) began at the end of 2019. COVID-19 is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and patients with COVID-19 may exhibit poor clinical outcomes. Some patients with severe COVID-19 experience cytokine release syndrome (CRS) or a cytokine storm-elevated levels of hyperactivated immune cells-and circulating pro-inflammatory cytokines, including interleukin (IL)-1ß and IL-18. This severe inflammatory response can lead to organ damage/failure and even death. The inflammasome is an intracellular immune complex that is responsible for the secretion of IL-1ß and IL-18 in various human diseases. Recently, there has been a growing number of studies revealing a link between the inflammasome and COVID-19. Therefore, this article summarizes the current literature regarding the inflammasome complex and COVID-19.


Subject(s)
COVID-19/immunology , COVID-19/virology , Inflammasomes/immunology , Inflammasomes/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Adaptive Immunity/immunology , Animals , COVID-19/complications , COVID-19/drug therapy , Cytokine Release Syndrome/drug therapy , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/immunology , Humans , Multiple Organ Failure/drug therapy , Multiple Organ Failure/etiology , Multiple Organ Failure/immunology
10.
EMBO J ; 40(18): e108249, 2021 09 15.
Article in English | MEDLINE | ID: covidwho-1323479

ABSTRACT

SARS-CoV-2 is an emerging coronavirus that causes dysfunctions in multiple human cells and tissues. Studies have looked at the entry of SARS-CoV-2 into host cells mediated by the viral spike protein and human receptor ACE2. However, less is known about the cellular immune responses triggered by SARS-CoV-2 viral proteins. Here, we show that the nucleocapsid of SARS-CoV-2 inhibits host pyroptosis by blocking Gasdermin D (GSDMD) cleavage. SARS-CoV-2-infected monocytes show enhanced cellular interleukin-1ß (IL-1ß) expression, but reduced IL-1ß secretion. While SARS-CoV-2 infection promotes activation of the NLRP3 inflammasome and caspase-1, GSDMD cleavage and pyroptosis are inhibited in infected human monocytes. SARS-CoV-2 nucleocapsid protein associates with GSDMD in cells and inhibits GSDMD cleavage in vitro and in vivo. The nucleocapsid binds the GSDMD linker region and hinders GSDMD processing by caspase-1. These insights into how SARS-CoV-2 antagonizes cellular inflammatory responses may open new avenues for treating COVID-19 in the future.


Subject(s)
COVID-19/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Nucleocapsid/metabolism , Phosphate-Binding Proteins/metabolism , Pyroptosis/physiology , SARS-CoV-2/metabolism , Angiotensin-Converting Enzyme 2/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , Caspase 1/immunology , Caspase 1/metabolism , HEK293 Cells , Host-Pathogen Interactions , Humans , Inflammasomes/immunology , Inflammasomes/metabolism , Interleukin-1beta/immunology , Interleukin-1beta/metabolism , Intracellular Signaling Peptides and Proteins/immunology , Mice , Monocytes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/immunology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Phosphate-Binding Proteins/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , THP-1 Cells
11.
Int J Mol Sci ; 22(13)2021 Jun 29.
Article in English | MEDLINE | ID: covidwho-1304667

ABSTRACT

Amyloid beta (Aß)-induced abnormal neuroinflammation is recognized as a major pathological feature of Alzheimer's disease (AD), which results in memory impairment. Research exploring low-grade systemic inflammation and its impact on the development and progression of neurodegenerative disease has increased. A particular research focus has been whether systemic inflammation arises only as a secondary effect of disease, or it is also a cause of pathology. The inflammasomes, and more specifically the NLRP3 inflammasome, are crucial components of the innate immune system and are usually activated in response to infection or tissue damage. Although inflammasome activation plays critical roles against various pathogens in host defense, overactivation of inflammasome contributes to the pathogenesis of inflammatory diseases, including acute central nervous system (CNS) injuries and chronic neurodegenerative diseases, such as AD. This review summarizes the current literature on the role of the NLRP3 inflammasome in the pathogenesis of AD, and its involvement in infections, particularly SARS-CoV-2. NLRP3 might represent the crossroad between the hypothesized neurodegeneration and the primary COVID-19 infection.


Subject(s)
Alzheimer Disease/pathology , Amyloid beta-Peptides/metabolism , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Alzheimer Disease/metabolism , Animals , Coronavirus/pathogenicity , Humans , Immunity, Innate , Microglia/metabolism , Virus Diseases/immunology , Virus Diseases/pathology
12.
Inflammopharmacology ; 29(4): 1049-1059, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1303332

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can enter the central nervous system and cause several neurological manifestations. Data from cerebrospinal fluid analyses and postmortem samples have been shown that SARS-CoV-2 has neuroinvasive properties. Therefore, ongoing studies have focused on mechanisms involved in neurotropism and neural injuries of SARS-CoV-2. The inflammasome is a part of the innate immune system that is responsible for the secretion and activation of several pro-inflammatory cytokines, such as interleukin-1ß, interleukin-6, and interleukin-18. Since cytokine storm has been known as a major mechanism followed by SARS-CoV-2, inflammasome may trigger an inflammatory form of lytic programmed cell death (pyroptosis) following SARS-CoV-2 infection and contribute to associated neurological complications. We reviewed and discussed the possible role of inflammasome and its consequence pyroptosis following coronavirus infections as potential mechanisms of neurotropism by SARS-CoV-2. Further studies, particularly postmortem analysis of brain samples obtained from COVID-19 patients, can shed light on the possible role of the inflammasome in neurotropism of SARS-CoV-2.


Subject(s)
COVID-19/metabolism , Central Nervous System/metabolism , Inflammasomes/metabolism , Pyroptosis/physiology , SARS-CoV-2/metabolism , Brain/immunology , Brain/metabolism , COVID-19/immunology , Central Nervous System/immunology , Humans , Inflammasomes/immunology , SARS-CoV-2/immunology
13.
Int J Mol Sci ; 22(13)2021 Jun 29.
Article in English | MEDLINE | ID: covidwho-1295856

ABSTRACT

Amyloid beta (Aß)-induced abnormal neuroinflammation is recognized as a major pathological feature of Alzheimer's disease (AD), which results in memory impairment. Research exploring low-grade systemic inflammation and its impact on the development and progression of neurodegenerative disease has increased. A particular research focus has been whether systemic inflammation arises only as a secondary effect of disease, or it is also a cause of pathology. The inflammasomes, and more specifically the NLRP3 inflammasome, are crucial components of the innate immune system and are usually activated in response to infection or tissue damage. Although inflammasome activation plays critical roles against various pathogens in host defense, overactivation of inflammasome contributes to the pathogenesis of inflammatory diseases, including acute central nervous system (CNS) injuries and chronic neurodegenerative diseases, such as AD. This review summarizes the current literature on the role of the NLRP3 inflammasome in the pathogenesis of AD, and its involvement in infections, particularly SARS-CoV-2. NLRP3 might represent the crossroad between the hypothesized neurodegeneration and the primary COVID-19 infection.


Subject(s)
Alzheimer Disease/pathology , Amyloid beta-Peptides/metabolism , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Alzheimer Disease/metabolism , Animals , Coronavirus/pathogenicity , Humans , Immunity, Innate , Microglia/metabolism , Virus Diseases/immunology , Virus Diseases/pathology
14.
Cytokine Growth Factor Rev ; 61: 2-15, 2021 10.
Article in English | MEDLINE | ID: covidwho-1275255

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits a wide spectrum of clinical presentations, ranging from asymptomatic cases to severe pneumonia or even death. In severe COVID-19 cases, an increased level of proinflammatory cytokines has been observed in the bloodstream, forming the so-called "cytokine storm". Generally, nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome activation intensely induces cytokine production as an inflammatory response to viral infection. Therefore, the NLRP3 inflammasome can be a potential target for the treatment of COVID-19. Hence, this review first introduces the canonical NLRP3 inflammasome activation pathway. Second, we review the cellular/molecular mechanisms of NLRP3 inflammasome activation by SARS-CoV-2 infection (e.g., viroporins, ion flux and the complement cascade). Furthermore, we describe the involvement of the NLRP3 inflammasome in the pathogenesis of COVID-19 (e.g., cytokine storm, respiratory manifestations, cardiovascular comorbidity and neurological symptoms). Finally, we also propose several promising inhibitors targeting the NLRP3 inflammasome, cytokine products and neutrophils to provide novel therapeutic strategies for COVID-19.


Subject(s)
COVID-19/drug therapy , COVID-19/metabolism , Inflammasomes/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , SARS-CoV-2/pathogenicity , Cytokine Release Syndrome/drug therapy , Cytokine Release Syndrome/metabolism , Humans , Inflammasomes/drug effects
15.
Elife ; 102021 06 21.
Article in English | MEDLINE | ID: covidwho-1278699

ABSTRACT

Increasing age is the strongest predictor of risk of COVID-19 severity and mortality. Immunometabolic switch from glycolysis to ketolysis protects against inflammatory damage and influenza infection in adults. To investigate how age compromises defense against coronavirus infection, and whether a pro-longevity ketogenic diet (KD) impacts immune surveillance, we developed an aging model of natural murine beta coronavirus (mCoV) infection with mouse hepatitis virus strain-A59 (MHV-A59). When inoculated intranasally, mCoV is pneumotropic and recapitulates several clinical hallmarks of COVID-19 infection. Aged mCoV-A59-infected mice have increased mortality and higher systemic inflammation in the heart, adipose tissue, and hypothalamus, including neutrophilia and loss of γδ T cells in lungs. Activation of ketogenesis in aged mice expands tissue protective γδ T cells, deactivates the NLRP3 inflammasome, and decreases pathogenic monocytes in lungs of infected aged mice. These data establish harnessing of the ketogenic immunometabolic checkpoint as a potential treatment against coronavirus infection in the aged.


Subject(s)
Coronavirus Infections/diet therapy , Diet, Ketogenic/methods , Murine hepatitis virus/pathogenicity , Age Factors , Aging , Animals , COVID-19/diet therapy , Coronavirus Infections/metabolism , Coronavirus Infections/mortality , Disease Models, Animal , Glycolysis , Humans , Inflammasomes/metabolism , Ketone Bodies/metabolism , Male , Mice , Mice, Inbred C57BL , Murine hepatitis virus/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , SARS-CoV-2
16.
Int J Mol Sci ; 22(12)2021 Jun 13.
Article in English | MEDLINE | ID: covidwho-1273455

ABSTRACT

Inflammation is an old concept that has started to be considered as an important factor in infection and chronic diseases. The role of leukocytes, the plasmatic components, then of the mediators such as prostaglandins, cytokines, and, in recent decades, of the endothelium has completed the concept of the inflammation process. The function of the endothelium appeared to be crucial as a regulator or the initiator of the inflammatory process. Culture of human endothelial cells and experimental systems made it possible to define the molecular basis of inflammation in vascular diseases, in diabetes mellitus, atherosclerosis, vasculitis and thromboembolic complications. Advanced glycation end product receptor (RAGE), present on endothelial cells (ECs) and monocytes, participates in the activation of these cells in inflammatory conditions. Inflammasome is a cytosolic multiprotein that controls the response to diverse microorganisms. It is positively regulated by stimulator of interferon response CGAMP interactor-1 (STING1). Angiogenesis and thrombotic events are dysregulated during inflammation. ECs appear to be a protector, but also a possible initiator of thrombosis.


Subject(s)
Atherosclerosis/pathology , Endothelium, Vascular/metabolism , Thrombosis/pathology , Atherosclerosis/metabolism , Endothelium, Vascular/cytology , Humans , Inflammasomes/metabolism , Membrane Proteins/metabolism , Neovascularization, Physiologic , Nitric Oxide/metabolism , Receptor for Advanced Glycation End Products/metabolism , Thrombosis/metabolism
17.
Nat Commun ; 12(1): 2735, 2021 05 12.
Article in English | MEDLINE | ID: covidwho-1241460

ABSTRACT

Inflammasomes are filamentous signaling platforms integral to innate immunity. Currently, little is known about how these structurally similar filaments recognize and distinguish one another. A cryo-EM structure of the AIM2PYD filament reveals that the architecture of the upstream filament is essentially identical to that of the adaptor ASCPYD filament. In silico simulations using Rosetta and molecular dynamics followed by biochemical and cellular experiments consistently demonstrate that individual filaments assemble bidirectionally. By contrast, the recognition between AIM2 and ASC requires at least one to be oligomeric and occurs in a head-to-tail manner. Using in silico mutagenesis as a guide, we also identify specific axial and lateral interfaces that dictate the recognition and distinction between AIM2 and ASC filaments. Together, the results here provide a robust framework for delineating the signaling specificity and order of inflammasomes.


Subject(s)
CARD Signaling Adaptor Proteins/metabolism , DNA-Binding Proteins/metabolism , Immunity, Innate/physiology , Inflammasomes/metabolism , CARD Signaling Adaptor Proteins/genetics , Cryoelectron Microscopy , DNA-Binding Proteins/genetics , HEK293 Cells , Humans , Molecular Dynamics Simulation , Mutation/genetics , Protein Structure, Secondary , Signal Transduction/physiology
18.
Immunity ; 54(7): 1463-1477.e11, 2021 07 13.
Article in English | MEDLINE | ID: covidwho-1263294

ABSTRACT

Acute respiratory distress syndrome (ARDS), an inflammatory condition with high mortality rates, is common in severe COVID-19, whose risk is reduced by metformin rather than other anti-diabetic medications. Detecting of inflammasome assembly in post-mortem COVID-19 lungs, we asked whether and how metformin inhibits inflammasome activation while exerting its anti-inflammatory effect. We show that metformin inhibited NLRP3 inflammasome activation and interleukin (IL)-1ß production in cultured and alveolar macrophages along with inflammasome-independent IL-6 secretion, thus attenuating lipopolysaccharide (LPS)- and SARS-CoV-2-induced ARDS. By targeting electron transport chain complex 1 and independently of AMP-activated protein kinase (AMPK) or NF-κB, metformin blocked LPS-induced and ATP-dependent mitochondrial (mt) DNA synthesis and generation of oxidized mtDNA, an NLRP3 ligand. Myeloid-specific ablation of LPS-induced cytidine monophosphate kinase 2 (CMPK2), which is rate limiting for mtDNA synthesis, reduced ARDS severity without a direct effect on IL-6. Thus, inhibition of ATP and mtDNA synthesis is sufficient for ARDS amelioration.


Subject(s)
Adenosine Triphosphate/metabolism , DNA, Mitochondrial/biosynthesis , Inflammasomes/drug effects , Metformin/pharmacology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Pneumonia/prevention & control , Animals , COVID-19/metabolism , COVID-19/prevention & control , Cytokines/genetics , Cytokines/metabolism , DNA, Mitochondrial/metabolism , Humans , Inflammasomes/metabolism , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Lipopolysaccharides/toxicity , Metformin/therapeutic use , Mice , Nucleoside-Phosphate Kinase/metabolism , Pneumonia/metabolism , Respiratory Distress Syndrome/chemically induced , Respiratory Distress Syndrome/prevention & control , SARS-CoV-2/pathogenicity
19.
Immunology ; 163(4): 377-388, 2021 08.
Article in English | MEDLINE | ID: covidwho-1247200

ABSTRACT

Apoptosis-associated speck-like protein containing a caspase recruit domain (ASC), encoded by PYCARD gene, is a 22 kDa small molecule, which aggregates into ASC specks during inflammasome activation. ASC protein is an adaptor protein present in several inflammasome complexes that performs several intra- and extracellular functions, in monomeric form or as ASC specks, during physiological and pathological processes related to inflammation and adaptive immunity. Extracellular ASC specks (eASC specks) released during cell death by pyroptosis can contribute as a danger signal to the propagation of inflammation via phagocytosis and activation of surrounding cells. ASC specks are found in the circulation of patients with chronic inflammatory diseases and have been considered as relevant blood biomarkers of inflammation. eASC amplifies the inflammatory signal, may induce the production of autoantibodies, transports molecules that bind to this complex, contributing to the generation of antibodies, and can induce the maturation of cytokines promoting the modelling of the adaptive immunity. Although several advances have been registered in the last 21 years, there are numerous unknown or enigmatic gaps in the understanding of the role of eASC specks in the organism. Here, we provide an overview about the ASC protein focusing on the probable roles of eASC specks in several diseases, up to the most recent studies concerning COVID-19.


Subject(s)
Adaptive Immunity , Alarmins/metabolism , CARD Signaling Adaptor Proteins/metabolism , Inflammasomes/metabolism , Inflammation Mediators/metabolism , Inflammation/metabolism , Animals , COVID-19/immunology , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , Host-Pathogen Interactions , Humans , Inflammasomes/immunology , Inflammation/immunology , Inflammation/pathology , Phagocytosis , Pyroptosis , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Signal Transduction
20.
Cells ; 10(4)2021 04 20.
Article in English | MEDLINE | ID: covidwho-1232578

ABSTRACT

Recent clinical trials have now firmly established that inflammation participates causally in human atherosclerosis. These observations point the way toward novel treatments that add to established therapies to help stem the growing global epidemic of cardiovascular disease. Fortunately, we now have a number of actionable targets whose clinical exploration will help achieve the goal of optimizing beneficial effects while avoiding undue interference with host defenses or other unwanted actions. This review aims to furnish the foundation for this quest by critical evaluation of the current state of anti-inflammatory interventions within close reach of clinical application, with a primary focus on innate immunity. In particular, this paper highlights the pathway from the inflammasome, through interleukin (IL)-1 to IL-6 supported by a promising body of pre-clinical, clinical, and human genetic data. This paper also considers the use of biomarkers to guide allocation of anti-inflammatory therapies as a step toward realizing the promise of precision medicine. The validation of decades of experimental work and association studies in humans by recent clinical investigations provides a strong impetus for further efforts to target inflammation in atherosclerosis to address the considerable risk that remains despite current therapies.


Subject(s)
Cardiovascular Diseases/pathology , Inflammasomes/metabolism , Inflammation/pathology , Interleukin-1/metabolism , Interleukin-6/metabolism , Animals , Humans , Precision Medicine
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