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1.
Nat Commun ; 13(1): 5204, 2022 09 03.
Article in English | MEDLINE | ID: covidwho-2008282

ABSTRACT

In addition to investigating the virology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), discovering the host-virus dependencies are essential to identify and design effective antiviral therapy strategy. Here, we report that the SARS-CoV-2 entry receptor, ACE2, conjugates with small ubiquitin-like modifier 3 (SUMO3) and provide evidence indicating that prevention of ACE2 SUMOylation can block SARS-CoV-2 infection. E3 SUMO ligase PIAS4 prompts the SUMOylation and stabilization of ACE2, whereas deSUMOylation enzyme SENP3 reverses this process. Conjugation of SUMO3 with ACE2 at lysine (K) 187 hampers the K48-linked ubiquitination of ACE2, thus suppressing its subsequent cargo receptor TOLLIP-dependent autophagic degradation. TOLLIP deficiency results in the stabilization of ACE2 and elevated SARS-CoV-2 infection. In conclusion, our findings suggest selective autophagic degradation of ACE2 orchestrated by SUMOylation and ubiquitination as a potential way to combat SARS-CoV-2 infection.


Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , Autophagy , Cysteine Endopeptidases/genetics , Cysteine Endopeptidases/metabolism , Humans , Intracellular Signaling Peptides and Proteins/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Sumoylation , Ubiquitin-Protein Ligases/metabolism
2.
Gene ; 840: 146772, 2022 Oct 05.
Article in English | MEDLINE | ID: covidwho-1983092

ABSTRACT

The expression of ULK1, a core protein of autophagy, is closely related to autophagic activity. Numerous studies have shown that pathological abnormal expression of ULK1 is associated with various human diseases such as neurological disorders, infections, cardiovascular diseases, liver diseases and cancers. In addition, new advances in the regulation of ULK1 have been identified. Furthermore, targeting ULK1 as a therapeutic strategy for diseases is gaining attention as new corresponding activators or inhibitors are being developed. In this review, we describe the structure and regulation of ULK1 as well as the current targeted activators and inhibitors. Moreover, we highlight the pathological disorders of ULK1 expression and its critical role in human diseases.


Subject(s)
Autophagy-Related Protein-1 Homolog/metabolism , Autophagy , Intracellular Signaling Peptides and Proteins/metabolism , Neoplasms , Autophagy/physiology , Autophagy-Related Protein-1 Homolog/chemistry , Autophagy-Related Protein-1 Homolog/genetics , Humans , Intracellular Signaling Peptides and Proteins/chemistry , Intracellular Signaling Peptides and Proteins/genetics , Neoplasms/genetics
3.
Biomed Pharmacother ; 153: 113414, 2022 Sep.
Article in English | MEDLINE | ID: covidwho-1936094

ABSTRACT

Targeting macrophage M1 polarization is a promising strategy with fewer detrimental effects in COVID-19 curation. Phenylethanoid glycosides (PhGs) of Cistanche tubulosa are a botanical drug to possess various anti-inflammation-related functions, such as immunomodulating, hepatoprotective or neuroprotective functions, whereas their anti-inflammatory activity is rarely understood. A search into their anti-inflammatory characteristics led to the isolation of 49 PhGs along with 15 new PhGs. Their inhibitory effects against M1 polarization induced by LPS plus IFN-γ were explored in RAW264.7 macrophages. Of these PhGs, tubuloside B (Tub B) exerted substantial NO scavenging effect both in chemical- and cell-based assays, and it inhibited massive production of cytokines and chemokines. Tub B decreased ERK1/2 phosphorylation via direct binding and inhibited the MAPK signaling pathway. Tub B also directly binded to Mob1 protein, thereby increased the stability and level of Mob1 protein by inhibiting ubiquitinated degradation. Mob1 was pivotal for the anti-inflammatory activity of Tub B, and it acted independently of the canonical Hippo-YAP pathway. Moreover, ERK1/2 and Mob1 also had a synergic effect on modulating the inflammatory response. Finally, these effects of Tub B were verified in mice with LPS-induced systemic inflammatory response syndrome. Taken together, these results indicated that Tub B acted as a promising agent against M1 macrophage activation by synergistically targeting ERK1/2 and Mob1, and that it may potentially be a drug candidate to prevent/treat inflammatory diseases, especially in COVID-19.


Subject(s)
COVID-19 , Cistanche , Animals , Anti-Inflammatory Agents/metabolism , Anti-Inflammatory Agents/pharmacology , COVID-19/drug therapy , Glucosides , Glycosides/pharmacology , Intracellular Signaling Peptides and Proteins/metabolism , Lipopolysaccharides/metabolism , Lipopolysaccharides/pharmacology , MAP Kinase Signaling System , Macrophage Activation , Macrophages/metabolism , Mice , Plant Extracts/pharmacology
4.
Respir Investig ; 60(6): 750-761, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-1926868

ABSTRACT

BACKGROUND: The role of programmed cell death, especially pyroptosis and apoptosis, in unfavorable immune responses in COVID-19 remains to be elucidated. METHODS: We conducted a cross-sectional analysis to investigate the association between the serum gasdermin D (GSDMD) levels, a pyroptotic marker, and caspase-cleaved cytokeratin 18 fragment (M30), an apoptotic marker, and the clinical status and abnormal chest computed tomography (CT) findings in patients with COVID-19. RESULTS: In this study, 46 patients diagnosed with COVID-19 were divided into the following three groups according to the disease severity: mild to moderate group (n = 10), severe group (n = 14), and critical group (n = 22). The serum GSDMD levels were higher in the critical group than in the mild to moderate group (P = 0.016). In contrast, serum M30 levels were lower in the critical group than in the severe group (P = 0.048). Patients who required mechanical ventilation or died had higher serum GSDMD levels than those who did not (P = 0.007). Area of consolidation only and of ground glass opacity plus consolidation positively correlated with serum GSDMD levels (r = 0.56, P < 0.001 and r = 0.53, P < 0.001, respectively). CONCLUSION: Higher serum GSDMD levels are associated with critical respiratory status and the consolidation area on chest CT in patients with COVID-19, suggesting that excessive activation of pyroptosis may affect the clinical manifestations in patients with COVID-19.


Subject(s)
COVID-19 , Humans , Phosphate-Binding Proteins/metabolism , COVID-19/diagnostic imaging , Cross-Sectional Studies , Intracellular Signaling Peptides and Proteins/metabolism , Neoplasm Proteins/metabolism , Tomography , Tomography, X-Ray Computed
5.
Cells ; 11(10)2022 05 23.
Article in English | MEDLINE | ID: covidwho-1903276

ABSTRACT

The pore-forming inflammatory cell death pathway, pyroptosis, was first described in the early 1990s and its role in health and disease has been intensively studied since. The effector molecule GSDMD is cleaved by activated caspases, mainly Caspase 1 or 11 (Caspase 4/5 in humans), downstream of inflammasome formation. In this review, we describe the molecular events related to GSDMD-mediated pore formation. Furthermore, we summarize the so far elucidated ways of SARS-CoV-2 induced NLRP3 inflammasome formation leading to pyroptosis, which strongly contributes to COVID-19 pathology. We also explore the potential of NLRP3 and GSDMD inhibitors as therapeutics to counter excessive inflammation.


Subject(s)
COVID-19 , Pyroptosis , Caspases/metabolism , Humans , Inflammasomes/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Phosphate-Binding Proteins/metabolism , SARS-CoV-2
6.
J Virol ; 96(5): e0208621, 2022 03 09.
Article in English | MEDLINE | ID: covidwho-1736026

ABSTRACT

Coronavirus infections induce the expression of multiple proinflammatory cytokines and chemokines. We have previously shown that in cells infected with gammacoronavirus infectious bronchitis virus (IBV), interleukin 6 (IL-6), and IL-8 were drastically upregulated, and the MAP kinase p38 and the integrated stress response pathways were implicated in this process. In this study, we report that coronavirus infection activates a negative regulatory loop that restricts the upregulation of a number of proinflammatory genes. As revealed by the initial transcriptomic and subsequent validation analyses, the anti-inflammatory adenine-uridine (AU)-rich element (ARE)-binding protein, zinc finger protein 36 (ZFP36), and its related family members were upregulated in cells infected with IBV and three other coronaviruses, alphacoronaviruses porcine epidemic diarrhea virus (PEDV), human coronavirus 229E (HCoV-229E), and betacoronavirus HCoV-OC43, respectively. Characterization of the functional roles of ZFP36 during IBV infection demonstrated that ZFP36 promoted the degradation of transcripts coding for IL-6, IL-8, dual-specificity phosphatase 1 (DUSP1), prostaglandin-endoperoxide synthase 2 (PTGS2) and TNF-α-induced protein 3 (TNFAIP3), through binding to AREs in these transcripts. Consistently, knockdown and inhibition of JNK and p38 kinase activities reduced the expression of ZFP36, as well as the expression of IL-6 and IL-8. On the contrary, overexpression of mitogen-activated protein kinase kinase 3 (MKK3) and MAPKAP kinase-2 (MK2), the upstream and downstream kinases of p38, respectively, increased the expression of ZFP36 and decreased the expression of IL-8. Taken together, this study reveals an important regulatory role of the MKK3-p38-MK2-ZFP36 axis in coronavirus infection-induced proinflammatory response. IMPORTANCE Excessive and uncontrolled induction and release of proinflammatory cytokines and chemokines, the so-called cytokine release syndrome (CRS), would cause life-threatening complications and multiple organ failure in severe coronavirus infections, including severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and COVID-19. This study reveals that coronavirus infection also induces the expression of ZFP36, an anti-inflammatory ARE-binding protein, promoting the degradation of ARE-containing transcripts coding for IL-6 and IL-8 as well as a number of other proteins related to inflammatory response. Furthermore, the p38 MAP kinase, its upstream kinase MKK3 and downstream kinase MK2 were shown to play a regulatory role in upregulation of ZFP36 during coronavirus infection cycles. This MKK3-p38-MK2-ZFP36 axis would constitute a potential therapeutic target for severe coronavirus infections.


Subject(s)
Coronavirus Infections/metabolism , Interleukin-6/metabolism , Interleukin-8/metabolism , Tristetraprolin/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , Adenine/metabolism , Animals , Cell Line , Chlorocebus aethiops , Coronavirus Infections/genetics , Gene Expression Regulation , Humans , Infectious bronchitis virus/metabolism , Infectious bronchitis virus/pathogenicity , Interleukin-6/genetics , Interleukin-8/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Phosphorylation , Protein Serine-Threonine Kinases/metabolism , Transcriptional Activation , Up-Regulation , Uridine/metabolism , Vero Cells
7.
Science ; 374(6571): 1076-1080, 2021 Nov 26.
Article in English | MEDLINE | ID: covidwho-1723462

ABSTRACT

Inflammatory processes that recruit leukocytes to injured or infected tissues are crucial for tissue repair and the elimination of pathogens. However, excessive or chronic inflammation promotes tissue damage and disease, as in arthritis, atherosclerosis, inflammatory bowel disease, and COVID-19. Intracellular constituents released from dying cells are among the stimuli that trigger proinflammatory gene expression programs in innate immune cells. We explore how programmed cell death mechanisms­apoptosis, necroptosis, and pyroptosis­may contribute to inflammatory disease. We discuss inhibition of cell death as a potential therapeutic strategy, focusing on the targets RIPK1 (receptor interacting serine/threonine kinase 1), NLRP3 (NLR family pyrin domain containing 3), and GSDMD (gasdermin D) as important mediators of lytic cell death. We also consider the potential benefits of limiting membrane rupture rather than cell death by targeting NINJ1.


Subject(s)
Apoptosis , Inflammation/physiopathology , Necroptosis , Pyroptosis , Animals , Caspase 8/metabolism , Cell Adhesion Molecules, Neuronal/antagonists & inhibitors , Cell Adhesion Molecules, Neuronal/metabolism , Fas-Associated Death Domain Protein/metabolism , Humans , Inflammasomes/metabolism , Inflammation/drug therapy , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Nerve Growth Factors/antagonists & inhibitors , Nerve Growth Factors/metabolism , Receptor-Interacting Protein Serine-Threonine Kinases/deficiency , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism
8.
FASEB J ; 36(3): e22234, 2022 03.
Article in English | MEDLINE | ID: covidwho-1702985

ABSTRACT

The transmembrane protease angiotensin converting enzyme 2 (ACE2) is a protective regulator within the renin angiotensin system and additionally represents the cellular receptor for SARS-CoV. The release of soluble ACE2 (sACE2) from the cell surface is hence believed to be a crucial part of its (patho)physiological functions, as both, ACE2 protease activity and SARS-CoV binding ability, are transferred from the cell membrane to body fluids. Yet, the molecular sources of sACE2 are still not completely investigated. In this study, we show different sources and prerequisites for the release of sACE2 from the cell membrane. By using inhibitors as well as CRISPR/Cas9-derived cells, we demonstrated that, in addition to the metalloprotease ADAM17, also ADAM10 is an important novel shedding protease of ACE2. Moreover, we observed that ACE2 can also be released in extracellular vesicles. The degree of either ADAM10- or ADAM17-mediated ACE2 shedding is dependent on stimulatory conditions and on the expression level of the pro-inflammatory ADAM17 regulator iRhom2. Finally, by using structural analysis and in vitro verification, we determined for the first time that the susceptibility to ADAM10- and ADAM17-mediated shedding is mediated by the collectrin-like part of ACE2. Overall, our findings give novel insights into sACE2 release by several independent molecular mechanisms.


Subject(s)
ADAM10 Protein/metabolism , ADAM17 Protein/metabolism , Amyloid Precursor Protein Secretases/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Extracellular Vesicles/metabolism , Membrane Glycoproteins/metabolism , Membrane Proteins/metabolism , SARS Virus/metabolism , ADAM10 Protein/genetics , ADAM17 Protein/genetics , Amyloid Precursor Protein Secretases/genetics , Angiotensin-Converting Enzyme 2/genetics , Clustered Regularly Interspaced Short Palindromic Repeats , Extracellular Vesicles/genetics , HEK293 Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Glycoproteins/genetics , Membrane Proteins/genetics , SARS Virus/genetics , SARS-CoV-2
9.
Front Immunol ; 12: 825358, 2021.
Article in English | MEDLINE | ID: covidwho-1662589

ABSTRACT

Coronavirus disease 2019 (COVID-19) raises the issue of how hypoxia destroys normal physiological function and host immunity against pathogens. However, there are few or no comprehensive omics studies on this effect. From an evolutionary perspective, animals living in complex and changeable marine environments might develop signaling pathways to address bacterial threats under hypoxia. In this study, the ancient genomic model animal Takifugu obscurus and widespread Vibrio parahaemolyticus were utilized to study the effect. T. obscurus was challenged by V. parahaemolyticus or (and) exposed to hypoxia. The effects of hypoxia and infection were identified, and a theoretical model of the host critical signaling pathway in response to hypoxia and infection was defined by methods of comparative metabolomics and proteomics on the entire liver. The changing trends of some differential metabolites and proteins under hypoxia, infection or double stressors were consistent. The model includes transforming growth factor-ß1 (TGF-ß1), hypoxia-inducible factor-1α (HIF-1α), and epidermal growth factor (EGF) signaling pathways, and the consistent changing trends indicated that the host liver tended toward cell proliferation. Hypoxia and infection caused tissue damage and fibrosis in the portal area of the liver, which may be related to TGF-ß1 signal transduction. We propose that LRG (leucine-rich alpha-2-glycoprotein) is widely involved in the transition of the TGF-ß1/Smad signaling pathway in response to hypoxia and pathogenic infection in vertebrates as a conserved molecule.


Subject(s)
Hypoxia/metabolism , Signal Transduction/physiology , Takifugu/metabolism , Takifugu/microbiology , Vibrio Infections/metabolism , Vibrio parahaemolyticus/pathogenicity , Animals , Epidermal Growth Factor/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Metabolomics/methods , Proteomics/methods , Transforming Growth Factor beta1/metabolism , Vibrio Infections/microbiology
10.
Nat Struct Mol Biol ; 28(7): 614-625, 2021 07.
Article in English | MEDLINE | ID: covidwho-1550333

ABSTRACT

p97 processes ubiquitinated substrates and plays a central role in cellular protein homeostasis. Here, we report a series of cryo-EM structures of the substrate-engaged human p97 complex with resolutions ranging from 2.9 to 3.8 Å that captured 'power-stroke'-like motions of both the D1 and D2 ATPase rings of p97. A key feature of these structures is the critical conformational changes of the intersubunit signaling (ISS) motifs, which tighten the binding of nucleotides and neighboring subunits and contribute to the spiral staircase conformation of the D1 and D2 rings. In addition, we determined the cryo-EM structure of human p97 in complex with NMS-873, a potent p97 inhibitor, at a resolution of 2.4 Å. The structures showed that NMS-873 binds at a cryptic groove in the D2 domain and interacts with the ISS motif, preventing its conformational change and thus blocking substrate translocation allosterically.


Subject(s)
Adenosine Triphosphate/chemistry , Protein Folding , Proteostasis/physiology , Signal Transduction/physiology , Valosin Containing Protein/metabolism , Acetanilides/pharmacology , Animals , Benzothiazoles/pharmacology , Cryoelectron Microscopy , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum-Associated Degradation/physiology , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Nuclear Proteins/metabolism , Proteasome Endopeptidase Complex/metabolism , Protein Conformation , Ubiquitinated Proteins/metabolism , Valosin Containing Protein/antagonists & inhibitors
11.
Nat Neurosci ; 24(11): 1522-1533, 2021 11.
Article in English | MEDLINE | ID: covidwho-1500484

ABSTRACT

Coronavirus disease 2019 (COVID-19) can damage cerebral small vessels and cause neurological symptoms. Here we describe structural changes in cerebral small vessels of patients with COVID-19 and elucidate potential mechanisms underlying the vascular pathology. In brains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals and animal models, we found an increased number of empty basement membrane tubes, so-called string vessels representing remnants of lost capillaries. We obtained evidence that brain endothelial cells are infected and that the main protease of SARS-CoV-2 (Mpro) cleaves NEMO, the essential modulator of nuclear factor-κB. By ablating NEMO, Mpro induces the death of human brain endothelial cells and the occurrence of string vessels in mice. Deletion of receptor-interacting protein kinase (RIPK) 3, a mediator of regulated cell death, blocks the vessel rarefaction and disruption of the blood-brain barrier due to NEMO ablation. Importantly, a pharmacological inhibitor of RIPK signaling prevented the Mpro-induced microvascular pathology. Our data suggest RIPK as a potential therapeutic target to treat the neuropathology of COVID-19.


Subject(s)
Blood-Brain Barrier/metabolism , Brain/metabolism , Coronavirus 3C Proteases/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Microvessels/metabolism , SARS-CoV-2/metabolism , Animals , Blood-Brain Barrier/pathology , Brain/pathology , Chlorocebus aethiops , Coronavirus 3C Proteases/genetics , Cricetinae , Female , Humans , Intracellular Signaling Peptides and Proteins/genetics , Male , Mesocricetus , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Microvessels/pathology , SARS-CoV-2/genetics , Vero Cells
12.
J Virol ; 95(19): e0085121, 2021 09 09.
Article in English | MEDLINE | ID: covidwho-1403028

ABSTRACT

Uncoordinated 51-like kinase 1 (ULK1) is a well-characterized initiator of canonical autophagy under basal or pathological conditions. Porcine hemagglutinating encephalomyelitis virus (PHEV), a neurotropic betacoronavirus (ß-CoV), impairs ULK1 kinase but hijacks autophagy to facilitate viral proliferation. However, the machinery of PHEV-induced autophagy initiation upon ULK1 kinase deficiency remains unclear. Here, the time course of PHEV infection showed a significant accumulation of autophagosomes (APs) in nerve cells in vivo and in vitro. Utilizing ULK1-knockout neuroblastoma cells, we have identified that ULK1 is not essential for productive AP formation induced by PHEV. In vitro phosphorylation studies discovered that mTORC1-regulated ULK1 activation stalls during PHEV infection, whereas AP biogenesis was controlled by AMPK-driven BECN1 phosphorylation. A lack of BECN1 is sufficient to block LC3 lipidation and disrupt recruitment of the LC3-ATG14 complex. Moreover, BECN1 acts as a bona fide substrate for ULK1-independent neural autophagy, and ectopic expression of BECN1 somewhat enhances PHEV replication. These findings highlight a novel machinery of noncanonical autophagy independent of ULK1 that bypasses the conserved initiation circuit of AMPK-mTORC1-ULK1, providing new insights into the interplay between neurotropic ß-CoV and the host. IMPORTANCE The ongoing coronavirus disease 2019 (COVID-19) pandemic alongside the outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) pose Betacoronavirus (ß-CoV) as a global public health challenge. Coronaviruses subvert, hijack, or utilize autophagy to promote proliferation, and thus, exploring the cross talk between ß-CoV and autophagy is of great significance in confronting future ß-CoV outbreaks. Porcine hemagglutinating encephalomyelitis virus (PHEV) is a highly neurotropic ß-CoV that invades the central nervous system (CNS) in pigs, but understanding of the pathogenesis for PHEV-induced neurological dysfunction is yet limited. Here, we discovered a novel regulatory principle of neural autophagy initiation during PHEV infection, where productive autophagosome (AP) biogenesis bypasses the multifaceted regulation of ULK1 kinase. The PHEV-triggered noncanonical autophagy underscores the complex interactions of virus and host and will help in the development of therapeutic strategies targeting noncanonical autophagy to treat ß-CoV disease.


Subject(s)
Autophagy-Related Protein-1 Homolog/genetics , Autophagy-Related Protein-1 Homolog/metabolism , Autophagy/physiology , Betacoronavirus 1/metabolism , Animals , Autophagosomes/metabolism , Beclin-1/metabolism , COVID-19 , Cell Line , Gene Knockout Techniques , Intracellular Signaling Peptides and Proteins/metabolism , Male , Mechanistic Target of Rapamycin Complex 1/metabolism , Mice , Mice, Inbred BALB C , Neurons/metabolism , Phosphorylation , SARS-CoV-2
13.
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
14.
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
15.
Mol Med Rep ; 24(2)2021 Aug.
Article in English | MEDLINE | ID: covidwho-1271003

ABSTRACT

Coronavirus disease 2019 (COVID­19), caused by the severe acute respiratory syndrome coronavirus­2 (SARS­CoV­2), led to an outbreak of viral pneumonia in December 2019. The present study aimed to investigate the host inflammatory response signature­caused by SARS­CoV­2 in human corneal epithelial cells (HCECs). The expression level of angiotensin­converting enzyme 2 (ACE2) in the human cornea was determined via immunofluorescence. In vitro experiments were performed in HCECs stimulated with the SARS­CoV­2 spike protein. Moreover, the expression levels of ACE2, IL­8, TNF­α, IL­6, gasdermin D (GSDMD) and IL­1ß in HCECs were detected using reverse transcription­quantitative PCR and/or western blotting. It was identified that ACE2 was expressed in normal human corneal epithelium and HCECs cultured in vitro. Furthermore, the expression levels of IL­8, TNF­α and IL­6 in HCECs were decreased following SARS­CoV­2 spike protein stimulation, while the expression levels of GSDMD and IL­1ß were increased. In conclusion, the present results demonstrated that the SARS­CoV­2 spike protein suppressed the host inflammatory response and induced pyroptosis in HCECs. Therefore, blocking the ACE2 receptor in HCECs may reduce the infection rate of COVID­19.


Subject(s)
Epithelium, Corneal/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Adult , Aged , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Cells, Cultured , Cornea/cytology , Epithelial Cells/cytology , Epithelial Cells/metabolism , Epithelial Cells/virology , Epithelium, Corneal/virology , Female , Humans , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Interleukin-6/genetics , Interleukin-6/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Male , Middle Aged , Phosphate-Binding Proteins/genetics , Phosphate-Binding Proteins/metabolism , Pyroptosis , Spike Glycoprotein, Coronavirus/genetics , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism , Up-Regulation
16.
Int J Mol Sci ; 22(5)2021 Mar 05.
Article in English | MEDLINE | ID: covidwho-1129733

ABSTRACT

While there are various kinds of drugs for type 2 diabetes mellitus at present, in this review article, we focus on metformin which is an insulin sensitizer and is often used as a first-choice drug worldwide. Metformin mainly activates adenosine monophosphate-activated protein kinase (AMPK) in the liver which leads to suppression of fatty acid synthesis and gluconeogenesis. Metformin activates AMPK in skeletal muscle as well, which increases translocation of glucose transporter 4 to the cell membrane and thereby increases glucose uptake. Further, metformin suppresses glucagon signaling in the liver by suppressing adenylate cyclase which leads to suppression of gluconeogenesis. In addition, metformin reduces autophagy failure observed in pancreatic ß-cells under diabetic conditions. Furthermore, it is known that metformin alters the gut microbiome and facilitates the transport of glucose from the circulation into excrement. It is also known that metformin reduces food intake and lowers body weight by increasing circulating levels of the peptide hormone growth/differentiation factor 15 (GDF15). Furthermore, much attention has been drawn to the fact that the frequency of various cancers is lower in subjects taking metformin. Metformin suppresses the mechanistic target of rapamycin (mTOR) by activating AMPK in pre-neoplastic cells, which leads to suppression of cell growth and an increase in apoptosis in pre-neoplastic cells. It has been shown recently that metformin consumption potentially influences the mortality in patients with type 2 diabetes mellitus and coronavirus infectious disease (COVID-19). Taken together, metformin is an old drug, but multifaceted mechanisms of action of metformin have been unraveled one after another in its long history.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Metformin/pharmacology , Autophagy/drug effects , COVID-19/complications , COVID-19/mortality , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/etiology , Diabetes Mellitus, Type 2/mortality , Gastrointestinal Microbiome/drug effects , Humans , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/metabolism , Intracellular Signaling Peptides and Proteins/drug effects , Intracellular Signaling Peptides and Proteins/metabolism
17.
Emerg Microbes Infect ; 10(1): 178-195, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-998195

ABSTRACT

The genome of SARS-CoV-2 encodes two viral proteases (NSP3/papain-like protease and NSP5/3C-like protease) that are responsible for cleaving viral polyproteins during replication. Here, we discovered new functions of the NSP3 and NSP5 proteases of SARS-CoV-2, demonstrating that they could directly cleave proteins involved in the host innate immune response. We identified 3 proteins that were specifically and selectively cleaved by NSP3 or NSP5: IRF-3, and NLRP12 and TAB1, respectively. Direct cleavage of IRF3 by NSP3 could explain the blunted Type-I IFN response seen during SARS-CoV-2 infections while NSP5 mediated cleavage of NLRP12 and TAB1 point to a molecular mechanism for enhanced production of cytokines and inflammatory responThe genome of SARS-CoV-2 encodes two viral proteases (NSP3/papain-like protease and NSP5/3C-like protease) that are responsible for cleaving viral polyproteins during replication. Here, we discovered new functions of the NSP3 and NSP5 proteases of SARS-CoV-2, demonstrating that they could directly cleave proteins involved in the host innate immune response. We identified 3 proteins that were specifically and selectively cleaved by NSP3 or NSP5: IRF-3, and NLRP12 and TAB1, respectively. Direct cleavage of IRF3 by NSP3 could explain the blunted Type-I IFN response seen during SARS-CoV-2 infections while NSP5 mediated cleavage of NLRP12 and TAB1 point to a molecular mechanism for enhanced production of cytokines and inflammatory response observed in COVID-19 patients. We demonstrate that in the mouse NLRP12 protein, one of the recognition site is not cleaved in our in-vitro assay. We pushed this comparative alignment of IRF-3 and NLRP12 homologs and show that the lack or presence of cognate cleavage motifs in IRF-3 and NLRP12 could contribute to the presentation of disease in cats and tigers, for example. Our findings provide an explanatory framework for indepth studies into the pathophysiology of COVID-19.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Coronavirus 3C Proteases/metabolism , Coronavirus Papain-Like Proteases/metabolism , Interferon Regulatory Factor-3/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Amino Acid Sequence , Animals , COVID-19/pathology , Cell Line , Chiroptera/virology , Coronavirus 3C Proteases/genetics , Coronavirus Papain-Like Proteases/genetics , HEK293 Cells , Humans , Mice , SARS-CoV-2/enzymology , SARS-CoV-2/genetics
18.
J Biol Chem ; 295(41): 14040-14052, 2020 10 09.
Article in English | MEDLINE | ID: covidwho-704089

ABSTRACT

Coronaviruses have caused several zoonotic infections in the past two decades, leading to significant morbidity and mortality globally. Balanced regulation of cell death and inflammatory immune responses is essential to promote protection against coronavirus infection; however, the underlying mechanisms that control these processes remain to be resolved. Here we demonstrate that infection with the murine coronavirus mouse hepatitis virus (MHV) activated the NLRP3 inflammasome and inflammatory cell death in the form of PANoptosis. Deleting NLRP3 inflammasome components or the downstream cell death executioner gasdermin D (GSDMD) led to an initial reduction in cell death followed by a robust increase in the incidence of caspase-8- and receptor-interacting serine/threonine-protein kinase 3 (RIPK3)-mediated inflammatory cell deathafter coronavirus infection. Additionally, loss of GSDMD promoted robust NLRP3 inflammasome activation. Moreover, the amounts of some cytokines released during coronavirus infection were significantly altered in the absence of GSDMD. Altogether, our findings show that inflammatory cell death, PANoptosis, is induced by coronavirus infection and that impaired NLRP3 inflammasome function or pyroptosis can lead to negative consequences for the host. These findings may have important implications for studies of coronavirus-induced disease.


Subject(s)
Caspase 8/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Pyroptosis , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Animals , Cells, Cultured , Coronavirus/physiology , Coronavirus Infections/metabolism , Coronavirus Infections/pathology , Coronavirus Infections/veterinary , Cytokines/metabolism , Inflammasomes/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Macrophages/cytology , Macrophages/metabolism , Macrophages/virology , Mice , Mice, Inbred C57BL , Mice, Knockout , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Necroptosis , Phosphate-Binding Proteins/genetics , Phosphate-Binding Proteins/metabolism
19.
J Lipid Res ; 61(7): 972-982, 2020 07.
Article in English | MEDLINE | ID: covidwho-382050

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2 has resulted in the death of more than 328,000 persons worldwide in the first 5 months of 2020. Herculean efforts to rapidly design and produce vaccines and other antiviral interventions are ongoing. However, newly evolving viral mutations, the prospect of only temporary immunity, and a long path to regulatory approval pose significant challenges and call for a common, readily available, and inexpensive treatment. Strategic drug repurposing combined with rapid testing of established molecular targets could provide a pause in disease progression. SARS-CoV-2 shares extensive structural and functional conservation with SARS-CoV-1, including engagement of the same host cell receptor (angiotensin-converting enzyme 2) localized in cholesterol-rich microdomains. These lipid-enveloped viruses encounter the endosomal/lysosomal host compartment in a critical step of infection and maturation. Niemann-Pick type C (NP-C) disease is a rare monogenic neurodegenerative disease caused by deficient efflux of lipids from the late endosome/lysosome (LE/L). The NP-C disease-causing gene (NPC1) has been strongly associated with viral infection, both as a filovirus receptor (e.g., Ebola) and through LE/L lipid trafficking. This suggests that NPC1 inhibitors or NP-C disease mimetics could serve as anti-SARS-CoV-2 agents. Fortunately, there are such clinically approved molecules that elicit antiviral activity in preclinical studies, without causing NP-C disease. Inhibition of NPC1 may impair viral SARS-CoV-2 infectivity via several lipid-dependent mechanisms, which disturb the microenvironment optimum for viral infectivity. We suggest that known mechanistic information on NPC1 could be utilized to identify existing and future drugs to treat COVID-19.


Subject(s)
Anticholesteremic Agents/therapeutic use , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Coronavirus Infections/drug therapy , Intracellular Signaling Peptides and Proteins/genetics , Niemann-Pick Disease, Type C/drug therapy , Pandemics , Pneumonia, Viral/drug therapy , Androstenes/therapeutic use , Angiotensin-Converting Enzyme 2 , Betacoronavirus/metabolism , Betacoronavirus/pathogenicity , COVID-19 , Cholesterol/metabolism , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Drug Repositioning/methods , Humans , Hydroxychloroquine/therapeutic use , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/metabolism , Lysosomes/drug effects , Lysosomes/metabolism , Lysosomes/virology , Niemann-Pick C1 Protein , Niemann-Pick Disease, Type C/genetics , Niemann-Pick Disease, Type C/metabolism , Niemann-Pick Disease, Type C/pathology , Peptidyl-Dipeptidase A/genetics , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , Protein Binding , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/genetics , Receptors, Virus/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
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