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1.
Front Immunol ; 13: 860977, 2022.
Article in English | MEDLINE | ID: mdl-35450066

ABSTRACT

Neuroinflammation is initiated in response to ischemic stroke, and is usually characterized by microglial activation and polarization. Stimulator of interferon genes (STING) has been shown to play a critical role in anti-tumor immunity and inflammatory diseases. Nevertheless, the effect and underlying mechanisms of STING on microglial polarization after ischemic stroke remain unclarified. In this study, acute ischemic stroke was simulated using a model of middle cerebral artery occlusion (MCAO) at adult male C57BL/6 mice in vivo and the BV2 microglia oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro. The specific STING inhibitor C-176 was administered intraperitoneally at 30min after MCAO. We found that the expression of microglial STING was increased following MCAO and OGD/R. Pharmacologic inhibition of STING with C-176 reduced the ischemia/reperfusion (I/R)-induced brain infarction, edema and neuronal injury. Moreover, blockade of STING improved neurological performance and cognitive function and attenuated neuronal degeneration in the hippocampus after MCAO. Mechanistically, both in vivo and in vitro, we delineated that STING could promote the polarization of microglia towards the M1 phenotype and restrain M2 microglia polarization via downstream pathways, including interferon regulatory factor 3 (IRF3) and nuclear factor-κB (NF-κB). In addition, mitochondrial DNA (mtDNA), which is released to microglial cytoplasm induced by I/R injury, could facilitate microglia towards M1 modality through STING signaling pathway. Treatment with C-176 abolished the detrimental effects of mtDNA on stroke outcomes. Taken together, these findings suggest that STING, activated by mtDNA, could polarize microglia to the M1 phenotype following MCAO. Inhibition of STING may serve as a potential therapeutic strategy to mitigate neuroinflammation after ischemic stroke.


Subject(s)
Brain Ischemia , Ischemic Stroke , Animals , Brain Ischemia/metabolism , DNA, Mitochondrial/metabolism , Infarction, Middle Cerebral Artery , Interferon Regulatory Factor-3/metabolism , Male , Membrane Proteins , Mice , Mice, Inbred C57BL , Microglia/metabolism , NF-kappa B/metabolism , Signal Transduction
2.
Mol Cancer ; 21(1): 97, 2022 Apr 09.
Article in English | MEDLINE | ID: mdl-35395767

ABSTRACT

BACKGROUND: N6-methyladenosine (m6A) RNA modification plays a critical role in various physiological and pathological conditions. However, the role of m6A modification in head and neck squamous cell carcinoma (HNSCC) remains elusive. METHODS: In this study, the expression of m6A demethylases was detected by HNSCC tissue microarray. m6A-RNA immunoprecipitation (MeRIP) sequencing and RNA sequencing were used to identify downstream targets of ALKBH5. Comprehensive identification of RNA-binding proteins by mass spectrometry (ChIRP-MS) was used to explore the m6A "readers". Tumor-infiltrating lymphocytes were analyzed in SCC7-bearing xenografts in C3H mice. RESULTS: Here, we demonstrate the downregulation of m6A status and upregulation of two demethylases in HNSCC. Silencing the m6A demethylase alkB homolog 5, RNA demethylase (ALKBH5) suppresses tumor progression in vitro and in vivo. m6A-RNA immunoprecipitation sequencing reveals that ALKBH5 downregulates the m6A modification of DDX58 mRNA. Moreover, RIG-I, encoded by the DDX58 mRNA, reverses the protumorigenic characteristics of ALKBH5. ChIRP-MS demonstrates that HNRNPC binds to the m6A sites of DDX58 mRNA to promote its maturation. ALKBH5 overexpression inhibits RIG-I-mediated IFNα secretion through the IKKε/TBK1/IRF3 pathway. The number of tumor-infiltrating lymphocytes in C3H immunocompetent mice is reduced by ALKBH5 overexpression and restored by IFNα administration. Upregulation of AKLBH5 negatively correlates with RIG-I and IFNα expression in HNSCC patients. CONCLUSIONS: These findings unveil a novel mechanism of immune microenvironment regulation mediated by m6A modification through the ALKBH5/RIG-I/IFNα axis, providing a rationale for therapeutically targeting epitranscriptomic modulators in HNSCC.


Subject(s)
AlkB Homolog 5, RNA Demethylase , Head and Neck Neoplasms , I-kappa B Kinase , Squamous Cell Carcinoma of Head and Neck , AlkB Homolog 5, RNA Demethylase/genetics , AlkB Homolog 5, RNA Demethylase/metabolism , Animals , DEAD Box Protein 58 , Head and Neck Neoplasms/genetics , Humans , I-kappa B Kinase/metabolism , Interferon Regulatory Factor-3/metabolism , Interferon-alpha , Mice , Mice, Inbred C3H , RNA, Messenger/genetics , Squamous Cell Carcinoma of Head and Neck/genetics , Tumor Microenvironment
3.
Sci Transl Med ; 14(637): eabh3831, 2022 Mar 23.
Article in English | MEDLINE | ID: mdl-35320000

ABSTRACT

Inflammation has profound but poorly understood effects on metabolism, especially in the context of obesity and nonalcoholic fatty liver disease (NAFLD). Here, we report that hepatic interferon regulatory factor 3 (IRF3) is a direct transcriptional regulator of glucose homeostasis through induction of Ppp2r1b, a component of serine/threonine phosphatase PP2A, and subsequent suppression of glucose production. Global ablation of IRF3 in mice on a high-fat diet protected against both steatosis and dysglycemia, whereas hepatocyte-specific loss of IRF3 affects only dysglycemia. Integration of the IRF3-dependent transcriptome and cistrome in mouse hepatocytes identifies Ppp2r1b as a direct IRF3 target responsible for mediating its metabolic actions on glucose homeostasis. IRF3-mediated induction of Ppp2r1b amplified PP2A activity, with subsequent dephosphorylation of AMPKα and AKT. Furthermore, suppression of hepatic Irf3 expression with antisense oligonucleotides reversed obesity-induced insulin resistance and restored glucose homeostasis in obese mice. Obese humans with NAFLD displayed enhanced activation of liver IRF3, with reversion after bariatric surgery. Hepatic PPP2R1B expression correlated with HgbA1C and was elevated in obese humans with impaired fasting glucose. We therefore identify the hepatic IRF3-PPP2R1B axis as a causal link between obesity-induced inflammation and dysglycemia and suggest an approach for limiting the metabolic dysfunction accompanying obesity-associated NAFLD.


Subject(s)
Insulin Resistance , Non-alcoholic Fatty Liver Disease , Animals , Insulin Resistance/physiology , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Mice , Non-alcoholic Fatty Liver Disease/complications , Non-alcoholic Fatty Liver Disease/genetics , Obesity/complications , Obesity/metabolism
4.
J Virol ; 96(7): e0020722, 2022 04 13.
Article in English | MEDLINE | ID: mdl-35297670

ABSTRACT

Long noncoding RNAs (lncRNAs) widely exist in the cells and play important roles in various biological processes. The role of lncRNAs in immunity remains largely unknown. lncRNA BST2-2 (lncBST2-2) was upregulated upon viral infection and dependent on the interferon (IFN)/JAK/STAT signaling pathway. There was no coding potential found in the lncBST2-2 transcript. Overexpression of lncBST2-2 inhibited the replication of hepatitis C virus (HCV), Newcastle disease virus (NDV), vesicular stomatitis virus (VSV), and herpes simplex virus (HSV), while knockdown of lncBST2-2 facilitated viral replication. Further studies showed that lncBST2-2 promoted the phosphorylation, dimerization, and nuclear transport of IRF3, promoting the production of IFNs. Importantly, lncBST2-2 interacted with the DNA-binding domain of IRF3, which augmented TBK1 and IRF3 interaction, thereby inducing robust production of IFNs. Moreover, lncBST2-2 impaired the interaction between IRF3 and PP2A-RACK1 complex, an essential step for the dephosphorylation of IRF3. These data shown that lncBST2-2 promotes the innate immune response to viral infection through targeting IRF3. Our study reveals the lncRNA involved in the activation of IRF3 and provides a new insight into the role of lncRNA in antiviral innate immunity. IMPORTANCE Innate immunity is an important part of the human immune system to resist the invasion of foreign pathogens. IRF3 plays a critical role in the innate immune response to viral infection. In this study, we demonstrated that lncBST2-2 plays an important role in innate immunity. Virus-induced lncBST2-2 positively regulates innate immunity by interacting with IRF3 and blocking the dephosphorylation effect of RACK1-PP2A complex on IRF3, thus inhibiting viral infection. Our study provides a new insight into the role of lncBST2-2 in the regulation of IRF3 signaling activation.


Subject(s)
Host-Pathogen Interactions , Immunity, Innate , RNA, Long Noncoding , Virus Diseases , Host-Pathogen Interactions/genetics , Host-Pathogen Interactions/immunology , Humans , Immunity, Innate/genetics , Interferon Regulatory Factor-3/metabolism , Interferons/metabolism , RNA, Long Noncoding/genetics , Virus Diseases/genetics , Virus Diseases/immunology , Virus Replication , Viruses/immunology
5.
Sci Rep ; 12(1): 3967, 2022 03 10.
Article in English | MEDLINE | ID: mdl-35273248

ABSTRACT

The human DEAD-box protein 3 (DDX3) has been reported as a positive regulator and functions in the induction of type I interferon signaling. We elucidated the function of DDX3 in the positive regulation of IFNB production in non-pDC cells. We found that DDX3 regulates virus-induced activation of IFNB at the level of IRF-3. However, it does not affect conventional innate signaling, including IRF-3 phosphorylation, dimerization, or nuclear translocation of IRF-3, but has some downstream events after IRF-3 phosphorylation. Co-immunoprecipitation analyses revealed that DDX3 interacts with IRF-3 through its DNA-binding domain and promotes IRF-3-mediated IFNB promoter activation. DDX3 does not affect the formation of the IRF-3/p300/CBP complex. Instead, ChIP and EMSA assay revealed that DDX3 promotes the recruitment of IRF-3 and transcriptional co-activator p300/CBP to the IFNB promoter. The ATP binding pocket of DDX3 is involved in this association and is essential for the transcriptional activation. Taken together, our study demonstrates that DDX3 plays an important role in guiding a transcription factor complex formed by antiviral signaling to the target gene promoter.


Subject(s)
DEAD-box RNA Helicases , Interferon Regulatory Factor-3 , Cell Nucleus/metabolism , DEAD-box RNA Helicases/genetics , DEAD-box RNA Helicases/metabolism , Humans , Immunoprecipitation , Interferon Regulatory Factor-3/metabolism , Promoter Regions, Genetic , Transcriptional Activation
6.
J Virol ; 96(7): e0000122, 2022 04 13.
Article in English | MEDLINE | ID: mdl-35254105

ABSTRACT

The induction of interferons (IFNs) plays an important role in the elimination of invading pathogens. Heat shock binding protein 21 (HBP21), first known as a molecular chaperone of HSP70, is involved in tumor development. Heat shock binding proteins have been shown to regulate diverse biological processes, such as cell cycle, kinetochore localization, transcription, and cilium formation. Their role in antimicrobial immunity remains unknown. Here, we found that HBP21 drives a positive feedback loop to promote IRF3-mediated IFN production triggered by viral infection. HBP21 deficiency significantly impaired the virus-induced production of IFN and resulted in greater susceptibility to viral infection both in vitro and in vivo. Mechanistically, HBP21 interacted with IRF3 and promoted the formation of a TBK1-IRF3 complex. Moreover, HBP21 abolished the interaction between PP2A and IRF3 to repress the dephosphorylation of IRF3. Analysis of HBP21 protein structure further confirmed that HBP21 promotes the activation of IRF3 by depressing the dephosphorylation of IRF3 by PP2A. Further study demonstrated that virus-induced phosphorylation of Ser85 and Ser153 of HBP21 itself is important for the phosphorylation and dimerization of IRF3. Our study identifies HBP21 as a new positive regulator of innate antiviral response, which adds novel insight into activation of IRF3 controlled by multiple networks that specify behavior of tumors and immunity. IMPORTANCE The innate immune system is the first-line host defense against microbial pathogen invasion. The physiological functions of molecular chaperones, involving cell differentiation, migration, proliferation and inflammation, have been intensively studied. HBP21 as a molecular chaperone is critical for tumor development. Tumor is related to immunity. Whether HBP21 regulates immunity remains unknown. Here, we found that HBP21 promotes innate immunity response by dual regulation of IRF3. HBP21 interacts with IRF3 and promotes the formation of a TBK1-IRF3 complex. Moreover, HBP21 disturbs the interaction between PP2A and IRF3 to depress the dephosphorylation of IRF3. Analysis of HBP21 protein structure confirms that HBP21 promotes the activation of IRF3 by blocking the dephosphorylation of IRF3 by PP2A. Interestingly, virus-induced Ser85 and Ser153 phosphorylation of HBP21 is important for IRF3 activation. Our findings add to the known novel immunological functions of molecular chaperones and provide new insights into the regulation of innate immunity.


Subject(s)
Immunity, Innate , Molecular Chaperones , Virus Diseases , Humans , Immunity, Innate/genetics , Immunity, Innate/immunology , Interferon Regulatory Factor-3/metabolism , Molecular Chaperones/metabolism , Phosphorylation , Virus Diseases/immunology
7.
PLoS Pathog ; 18(3): e1010366, 2022 03.
Article in English | MEDLINE | ID: mdl-35235615

ABSTRACT

Tryptophan (Trp) metabolism through the kynurenine pathway (KP) is well known to play a critical function in cancer, autoimmune and neurodegenerative diseases. However, its role in host-pathogen interactions has not been characterized yet. Herein, we identified that kynurenine-3-monooxygenase (KMO), a key rate-limiting enzyme in the KP, and quinolinic acid (QUIN), a key enzymatic product of KMO enzyme, exerted a novel antiviral function against a broad range of viruses. Mechanistically, QUIN induced the production of type I interferon (IFN-I) via activating the N-methyl-d-aspartate receptor (NMDAR) and Ca2+ influx to activate Calcium/calmodulin-dependent protein kinase II (CaMKII)/interferon regulatory factor 3 (IRF3). Importantly, QUIN treatment effectively inhibited viral infections and alleviated disease progression in mice. Furthermore, kmo-/- mice were vulnerable to pathogenic viral challenge with severe clinical symptoms. Collectively, our results demonstrated that KMO and its enzymatic product QUIN were potential therapeutics against emerging pathogenic viruses.


Subject(s)
Kynurenine 3-Monooxygenase , Virus Diseases , Animals , Calcium/metabolism , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Interferon Regulatory Factor-3/metabolism , Kynurenine/metabolism , Kynurenine 3-Monooxygenase/metabolism , Mice , Quinolinic Acid/metabolism , Quinolinic Acid/pharmacology , Virus Diseases/drug therapy
8.
Viruses ; 14(2)2022 02 03.
Article in English | MEDLINE | ID: mdl-35215908

ABSTRACT

The transcription factors IRF3 and NF-κB are crucial in innate immune signalling in response to many viral and bacterial pathogens. However, mechanisms leading to their activation remain incompletely understood. Viral RNA can be detected by RLR receptors, such as RIG-I and MDA5, and the dsRNA receptor TLR3. Alternatively, the DExD-Box RNA helicases DDX1-DDX21-DHX36 activate IRF3/NF-κB in a TRIF-dependent manner independent of RIG-I, MDA5, or TLR3. Here, we describe DDX50, which shares 55.6% amino acid identity with DDX21, as a non-redundant factor that promotes activation of the IRF3 signalling pathway following its stimulation with viral RNA or infection with RNA and DNA viruses. Deletion of DDX50 in mouse and human cells impaired IRF3 phosphorylation and IRF3-dependent endogenous gene expression and cytokine/chemokine production in response to cytoplasmic dsRNA (polyIC transfection), and infection by RNA and DNA viruses. Mechanistically, whilst DDX50 co-immunoprecipitated TRIF, it acted independently to the previously described TRIF-dependent RNA sensor DDX1. Indeed, shRNA-mediated depletion of DDX1 showed DDX1 was dispensable for signalling in response to RNA virus infection. Importantly, loss of DDX50 resulted in a significant increase in replication and dissemination of virus following infection with vaccinia virus, herpes simplex virus, or Zika virus, highlighting its important role as a broad-ranging viral restriction factor.


Subject(s)
DEAD-box RNA Helicases/metabolism , Herpes Simplex/metabolism , Interferon Regulatory Factor-3/metabolism , Simplexvirus/physiology , Vaccinia virus/physiology , Vaccinia/metabolism , Zika Virus Infection/metabolism , Zika Virus/physiology , Animals , DEAD-box RNA Helicases/genetics , Herpes Simplex/genetics , Herpes Simplex/virology , Host-Pathogen Interactions , Humans , Interferon Regulatory Factor-3/genetics , Mice , Phosphorylation , Signal Transduction , Simplexvirus/genetics , Vaccinia/genetics , Vaccinia/virology , Vaccinia virus/genetics , Zika Virus/genetics , Zika Virus Infection/genetics , Zika Virus Infection/virology
9.
Microbiol Spectr ; 10(1): e0188321, 2022 02 23.
Article in English | MEDLINE | ID: mdl-35196784

ABSTRACT

Virus infection triggers intricate signal cascade reactions to activate the host innate immunity, which leads to the production of type I interferon (IFN-I). Herpes simplex virus 1 (HSV-1), a human-restricted pathogen, is capable of encoding over 80 viral proteins, and several of them are involved in immune evasion to resist the host antiviral response through the IFN-I signaling pathway. Here, we determined that HSV-1 UL31, which is associated with nuclear matrix and is essential for the formation of viral nuclear egress complex, could inhibit retinoic acid-inducible gene I (RIG-I)-like receptor pathway-mediated interferon beta (IFN-ß)-luciferase (Luc) and (PRDIII-I)4-Luc (an expression plasmid of IFN-ß positive regulatory elements III and I) promoter activation, as well as the mRNA transcription of IFN-ß and downstream interferon-stimulated genes (ISGs), such as ISG15, ISG54, ISG56, etc., to promote viral infection. UL31 was shown to restrain IFN-ß activation at the interferon regulatory factor 3 (IRF3)/IRF7 level. Mechanically, UL31 was demonstrated to interact with TANK binding kinase 1 (TBK1), inducible IκB kinase (IKKi), and IRF3 to impede the formation of the IKKi-IRF3 complex but not the formation of the IRF7-related complex. UL31 could constrain the dimerization and nuclear translocation of IRF3. Although UL31 was associated with the CREB binding protein (CBP)/p300 coactivators, it could not efficiently hamper the formation of the CBP/p300-IRF3 complex. In addition, UL31 could facilitate the degradation of IKKi and IRF3 by mediating their K48-linked polyubiquitination. Taken together, these results illustrated that UL31 was able to suppress IFN-ß activity by inhibiting the activation of IKKi and IRF3, which may contribute to the knowledge of a new immune evasion mechanism during HSV-1 infection. IMPORTANCE The innate immune system is the first line of host defense against the invasion of pathogens. Among its mechanisms, IFN-I is an essential cytokine in the antiviral response, which can help the host eliminate a virus. HSV-1 is a double-stranded DNA virus that can cause herpes and establish a lifelong latent infection, due to its possession of multiple mechanisms to escape host innate immunity. In this study, we illustrate for the first time that the HSV-1-encoded UL31 protein has a negative regulatory effect on IFN-ß production by blocking the dimerization and nuclear translocation of IRF3, as well as promoting the K48-linked polyubiquitination and degradation of both IKKi and IRF3. This study may be helpful for fully understanding the pathogenesis of HSV-1.


Subject(s)
Herpesvirus 1, Human/genetics , Herpesvirus 1, Human/immunology , Interferon-beta/genetics , Interferon-beta/immunology , Nuclear Proteins/genetics , Nuclear Proteins/immunology , Viral Proteins/genetics , Viral Proteins/immunology , Animals , Chlorocebus aethiops , Cytokines , DEAD Box Protein 58 , HEK293 Cells , HeLa Cells , Herpes Simplex , Host-Pathogen Interactions , Humans , Immune Evasion , Immunity, Innate , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/immunology , Interferon Regulatory Factor-3/metabolism , Interferon Regulatory Factor-7 , Interferon Type I , Interferon-beta/metabolism , Nuclear Proteins/metabolism , Receptors, Immunologic , Signal Transduction , Vero Cells , Viral Proteins/metabolism
10.
J Cell Mol Med ; 26(8): 2139-2151, 2022 04.
Article in English | MEDLINE | ID: mdl-35174638

ABSTRACT

Psoriasis and type 2 diabetes mellitus (T2DM) share similar inflammatory pathways in their pathogenesis. The stimulator of interferon genes (STING)-interferon regulatory factor 3 (IRF3) pathway has recently been shown to play an important role in immune and metabolic diseases. In this study, we investigated the activation of the STING-IRF3 pathway in human immortalized keratinocytes (HaCaT) cells treated with palmitic acid (PA) and imiquimod (IMQ). Additionally, we detected the STING-IRF3 pathway in diabetic mice with imiquimod (IMQ)-induced psoriasis and assessed the potential of STING inhibitor C-176. Furthermore, skin samples from patients with psoriasis and diabetes were collected for immunohistochemical analysis. The results indicated that the STING-IRF3 pathway was activated in HaCaT cells. Moreover, the STING pathway was also found to be induced in the skin tissue of diabetic mice with psoriasis; the inflammatory responses were ameliorated by treatment with C-176. In the skin tissue samples of patients with psoriasis and diabetes, immunohistochemistry showed that the expression levels of STING and phosphorylated IRF3 were also significantly increased. Thus, we conclude that the STING-IRF3 pathway is involved in the inflammatory response in the manifestation of psoriasis with T2DM. Inhibition of the activation of the STING pathway can ameliorate the development of psoriasis in diabetes and could be targeted for the development of therapeutic agents for these conditions.


Subject(s)
Diabetes Mellitus, Experimental , Diabetes Mellitus, Type 2 , Psoriasis , Animals , Diabetes Mellitus, Type 2/complications , Humans , Imiquimod/adverse effects , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Mice , Psoriasis/drug therapy
11.
Cell Rep ; 38(7): 110373, 2022 02 15.
Article in English | MEDLINE | ID: mdl-35172162

ABSTRACT

mRNA m6A modification is heavily involved in modulation of immune responses. However, its function in antiviral immunity is controversial, and how immune responses regulate m6A modification remains elusive. We here find TBK1, a key kinase of antiviral pathways, phosphorylates the core m6A methyltransferase METTL3 at serine 67. The phosphorylated METTL3 interacts with the translational complex, which is required for enhancing protein translation, thus facilitating antiviral responses. TBK1 also promotes METTL3 activation and m6A modification to stabilize IRF3 mRNA. Type I interferon (IFN) induction is severely impaired in METTL3-deficient cells. Mettl3fl/fl-lyz2-Cre mice are more susceptible to influenza A virus (IAV)-induced lethality than control mice. Consistently, Ythdf1-/- mice show higher mortality than wild-type mice due to decreased IRF3 expression and subsequently attenuated IFN production. Together, we demonstrate that innate signals activate METTL3 via TBK1, and METTL3-mediated m6A modification secures antiviral immunity by promoting mRNA stability and protein translation.


Subject(s)
Antiviral Agents/immunology , Immunity, Innate , Methyltransferases/metabolism , /metabolism , Adenosine/analogs & derivatives , Adenosine/metabolism , Amino Acid Sequence , Animals , Cell Line , Humans , Interferon Regulatory Factor-3/metabolism , Interferon Type I/metabolism , Methyltransferases/chemistry , Mice, Inbred C57BL , Phosphorylation , Protein Binding , Protein Biosynthesis , RNA-Binding Proteins/metabolism , Virus Diseases/immunology , Virus Diseases/pathology
12.
PLoS Pathog ; 18(2): e1010233, 2022 02.
Article in English | MEDLINE | ID: mdl-35108342

ABSTRACT

Schistosomiasis, which is caused by infection with Schistosoma spp., is characterized by granuloma and fibrosis in response to egg deposition. Pattern recognition receptors are important to sense invading Schistosoma, triggering an innate immune response, and subsequently shaping adaptive immunity. Cyclic GMP-AMP synthase (cGAS) was identified as a major cytosolic DNA sensor, which catalyzes the formation of cyclic GMP-AMP (cGAMP), a critical second messenger for the activation of the adaptor protein stimulator of interferon genes (STING). The engagement of STING by cGAMP leads to the activation of TANK-binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3), and the subsequent type I interferon (IFN) response. cGAS is suggested to regulate infectious diseases, autoimmune diseases, and cancer. However, the function of cGAS in helminth infection is unclear. In this study, we found that Cgas deficiency enhanced the survival of mice infected with S. japonicum markedly, without affecting the egg load in the liver. Consistently, Cgas deletion alleviated liver pathological impairment, reduced egg granuloma formation, and decreased fibrosis severity. In contrast, Sting deletion reduced the formation of egg granulomas markedly, but not liver fibrosis. Notably, Cgas or Sting deficiency reduced the production of IFNß drastically in mice infected with S. japonicum. Intriguingly, intravenous administration of recombinant IFNß exacerbated liver damage and promoted egg granuloma formation, without affecting liver fibrosis. Clodronate liposome-mediated depletion of macrophages indicated that macrophages are the major type of cells contributing to the induction of the type I IFN response during schistosome infection. Moreover, cGAS is important for type I IFN production and phosphorylation of TBK1 and IRF3 in response to stimulation with S. japonicum egg- or adult worm-derived DNA in macrophages. Our results clarified the immunomodulatory effect of cGAS in the regulation of liver granuloma formation during S. japonicum infection, involving sensing schistosome-derived DNA and producing type I IFN. Additionally, we showed that cGAS regulates liver fibrosis in a STING-type I-IFN-independent manner.


Subject(s)
Interferon Type I/immunology , Membrane Proteins/immunology , Nucleotidyltransferases/immunology , Schistosomiasis japonica/immunology , Schistosomiasis/immunology , Schistosomiasis/parasitology , Animals , Female , Immunity , Interferon Regulatory Factor-3/metabolism , Interferon Type I/metabolism , Membrane Proteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Nucleotidyltransferases/metabolism , Signal Transduction
13.
Front Cell Infect Microbiol ; 11: 818969, 2021.
Article in English | MEDLINE | ID: mdl-35096660

ABSTRACT

African swine fever (ASF) is a devastating infectious disease caused by African swine fever virus (ASFV). The ASFV genome encodes multiple structural and non-structural proteins that contribute to evasion of host immunity. In this study, we determined that the viral non-structural protein MGF360-14L inhibits interferon-ß (IFN-ß) promoter activity induced by cGAS-STING signaling. MGF360-14L was also found to downregulate expression of the IRF3 protein and promote its degradation through ubiquitin-meditated proteolysis. Moreover, MGF360-14L was shown to interact with and destabilize IRF3 by facilitating E3 ligase TRIM21-mediated K63-linked ubiquitination of IRF3. Overall, our study revealed that MGF360-14L promotes degradation of IRF3 through TRIM21, thereby inhibiting type I interferon production. These findings provide new insights into the mechanisms underlying ASFV immune evasion.


Subject(s)
African Swine Fever Virus , African Swine Fever , Interferon Regulatory Factor-3 , African Swine Fever/immunology , African Swine Fever/metabolism , African Swine Fever Virus/pathogenicity , Animals , Immunity, Innate , Interferon Regulatory Factor-3/metabolism , Interferon-beta/metabolism , Ribonucleoproteins/metabolism , Signal Transduction , Swine
14.
Front Cell Infect Microbiol ; 11: 789462, 2021.
Article in English | MEDLINE | ID: mdl-35083167

ABSTRACT

Corona virus disease 2019 (COVID-19) pathogenesis is intimately linked to the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) and disease severity has been associated with compromised induction of type I interferon (IFN-I) cytokines which coordinate the innate immune response to virus infections. Here we identified the SARS-CoV-2 encoded protein, Spike, as an inhibitor of IFN-I that antagonizes viral RNA pattern recognition receptor RIG-I signaling. Ectopic expression of SARS-CoV-2 Spike blocked RIG-I mediated activation of IFNß and downstream induction of interferon stimulated genes. Consequently, SARS-CoV-2 Spike expressing cells harbored increased RNA viral burden compared to control cells. Co-immunoprecipitation experiments revealed SARS-CoV-2 Spike associated with interferon regulatory factor 3 (IRF3), a key transcription factor that governs IFN-I activation. Co-expression analysis via immunoassays further indicated Spike specifically suppressed IRF3 expression as NF-κB and STAT1 transcription factor levels remained intact. Further biochemical experiments uncovered SARS-CoV-2 Spike potentiated proteasomal degradation of IRF3, implicating a novel mechanism by which SARS-CoV-2 evades the host innate antiviral immune response to facilitate COVID-19 pathogenesis.


Subject(s)
/immunology , COVID-19 , Immunity, Innate , Interferon Regulatory Factor-3 , Spike Glycoprotein, Coronavirus/immunology , COVID-19/immunology , HEK293 Cells , Humans , Interferon Regulatory Factor-3/metabolism , Interferon Type I/metabolism , SARS-CoV-2
15.
Cells ; 11(2)2022 01 11.
Article in English | MEDLINE | ID: mdl-35053345

ABSTRACT

M2-polarization and the tumoricidal to tumor-promoting transition are commonly observed with tumor-infiltrating macrophages after interplay with cancer cells or/and other stroma cells. Our previous study indicated that macrophage M2-polarization can be induced by extracellular HSP90α (eHSP90α) secreted from endothelial-to-mesenchymal transition-derived cancer-associated fibroblasts. To extend the finding, we herein validated that eHSP90α-induced M2-polarized macrophages exhibited a tumor-promoting activity and the promoted tumor tissues had significant increases in microvascular density but decreases in CD4+ T-cell level. We further investigated the signaling pathways occurring in eHSP90α-stimulated macrophages. When macrophages were exposed to eHSP90α, CD91 and toll-like receptor 4 (TLR4) functioned as the receptor/co-receptor for eHSP90α binding to recruit interleukin (IL)-1 receptor-associated kinases (IRAKs) and myeloid differentiation factor 88 (MyD88), and next elicited a canonical CD91/MyD88-IRAK1/4-IκB kinase α/ß (IKKα/ß)-nuclear factor-κB (NF-κB)/interferon regulatory factor 3 (IRF3) signaling pathway. Despite TLR4-MyD88 complex-associated activations of IKKα/ß, NF-κB and IRF3 being well-known as involved in macrophage M1-activation, our results demonstrated that the CD91-TLR4-MyD88 complex-associated IRAK1/4-IKKα/ß-NF-κB/IRF3 pathway was not only directly involved in M2-associated CD163, CD204, and IL-10 gene expressions but also required for downregulation of M1 inflammatory cytokines. Additionally, Janus kinase 2 (JAK2) and tyrosine kinase 2 (TYK2) were recruited onto MyD88 to induce the phosphorylation and activation of the transcription factor signal transducer and activator of transcription-3 (STAT-3). The JAK2/TYK2-STAT-3 signaling is known to associate with tumor promotion. In this study, the MyD88-JAK2/TYK2-STAT-3 pathway was demonstrated to contribute to eHSP90α-induced macrophage M2-polarization by regulating the expressions of M1- and M2-related genes, proangiogenic protein vascular endothelial growth factor, and phagocytosis-interfering factor Sec22b.


Subject(s)
Extracellular Space/chemistry , HSP90 Heat-Shock Proteins/metabolism , Interferon Regulatory Factor-3/metabolism , Janus Kinase 2/metabolism , Macrophages/metabolism , Myeloid Differentiation Factor 88/metabolism , NF-kappa B/metabolism , TYK2 Kinase/metabolism , Animals , Biomarkers/metabolism , Cell Line, Tumor , Cell Polarity , Human Umbilical Vein Endothelial Cells/metabolism , Humans , I-kappa B Kinase/metabolism , Interleukin-1 Receptor-Associated Kinases/metabolism , Low Density Lipoprotein Receptor-Related Protein-1/metabolism , Macrophages/cytology , Mice , Mice, Inbred C57BL , Models, Biological , Neoplasms , Neovascularization, Physiologic , Phagocytosis , RAW 264.7 Cells , STAT3 Transcription Factor/metabolism , Signal Transduction , Toll-Like Receptor 4/metabolism
16.
Sci Rep ; 12(1): 364, 2022 01 10.
Article in English | MEDLINE | ID: mdl-35013429

ABSTRACT

RNA-binding proteins (RBPs) interact with and determine the fate of many cellular RNAs directing numerous essential roles in cellular physiology. Nuclear Factor 90 (NF90) is an RBP encoded by the interleukin enhancer-binding factor 3 (ILF3) gene that has been found to influence RNA metabolism at several levels, including pre-RNA splicing, mRNA turnover, and translation. To systematically identify the RNAs that interact with NF90, we carried out iCLIP (individual-nucleotide resolution UV crosslinking and immunoprecipitation) analysis in the human embryonic fibroblast cell line HEK-293. Interestingly, many of the identified RNAs encoded proteins involved in the response to viral infection and RNA metabolism. We validated a subset of targets and investigated the impact of NF90 on their expression levels. Two of the top targets, IRF3 and IRF9 mRNAs, encode the proteins IRF3 and IRF9, crucial regulators of the interferon pathway involved in the SARS-CoV-2 immune response. Our results support a role for NF90 in modulating key genes implicated in the immune response and offer insight into the immunological response to the SARS-CoV-2 infection.


Subject(s)
COVID-19/metabolism , Immunoprecipitation/methods , Nuclear Factor 90 Proteins/metabolism , RNA-Binding Proteins/metabolism , RNA/metabolism , SARS-CoV-2/metabolism , COVID-19/virology , Cells, Cultured , HEK293 Cells , Humans , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Interferon-Stimulated Gene Factor 3, gamma Subunit/genetics , Interferon-Stimulated Gene Factor 3, gamma Subunit/metabolism , Nuclear Factor 90 Proteins/genetics , Protein Binding , RNA/genetics , RNA Interference , RNA Stability , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA-Binding Proteins/genetics , RNA-Seq/methods , SARS-CoV-2/genetics , SARS-CoV-2/physiology
17.
Cell Cycle ; 21(4): 392-405, 2022 02.
Article in English | MEDLINE | ID: mdl-34983293

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is considered one most aggressive and lethal cancer types worldwide. While its underlying mechanisms are still poorly understood. CircRNAs play essential roles in various biological progression, including PDAC. Here, our results found that circUHRF1 was highly expressed in PDAC tumor tissues compared with normal tissues. Next, Cell or animal models were constructed, CCK-8, cell colony, EdU, flow cytometry assay, transwell migration, and Western blot assays were applied. CircUHRF1 knockdown influenced PDAC cell proliferation, apoptosis, migration and EMT level in vitro, and tumor growth in vivo. Subsequently, bioinformatics analysis, AGO2-RIP, RNA pull-down, and dual-luciferase reporter assays were used to explore the downstream targets in PDAC progression. Our findings suggest that circUHRF1 regulated ARL4C expression to promote PDAC progression through sponging miR-1306-5p. The role of miR-1306-5p in PDAC cellular progression has been elucidated, and the expression association between miR-1306-5p and circUHRF1 or ARL4C in PDAC tissues was analyzed. Furthermore, circUHRF1 expression in PDAC cells could be transcriptionally regulated by IRF3. Collectively, our study demonstrated the role of IRF3/circUHRF1/miR-1306-5p/ARL4C axis in PDAC progression. Our results suggest that circUHRF1 is one promising diagnosis or therapeutic target for PDAC management.Abbreviations : CircRNA; Circular RNAPDAC; pancreatic ductal adenocarcinomaUHRF1; Ubiquitin-like with PHD and RING finger domain 1ARL4C; ADP Ribosylation Factor Like GTPase 4CRIP; RNA immunoprecipitationEDU; 5-Ethynyl-2'-deoxyuridineEMT; epithelial to mesenchymal transitionAGO2; Argonaute RISC Catalytic Component 2CCK8; Cell counting Kit-8IRF3; Interferon Regulatory Factor 3.


Subject(s)
Carcinoma, Pancreatic Ductal , MicroRNAs , Pancreatic Neoplasms , Animals , Carcinoma, Pancreatic Ductal/pathology , Cell Line, Tumor , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , MicroRNAs/genetics , MicroRNAs/metabolism , Pancreatic Neoplasms/pathology , RNA, Circular
18.
Sci Signal ; 15(715): eabh0068, 2022 01 04.
Article in English | MEDLINE | ID: mdl-34982578

ABSTRACT

The transcription regulator ID2 plays an essential role in the development and differentiation of immune cells. Here, we report that ID2 also negatively regulates antiviral innate immune responses. During viral infection of human epithelial cells, ID2 bound to TANK-binding kinase 1 (TBK1) and to inhibitor of nuclear factor κB kinase ε (IKKε). These interactions inhibited the recruitment and activation of interferon (IFN) regulatory factor 3 (IRF3) by TBK1 or IKKε, leading to a reduction in the expression of IFN-ß1 (IFNB1). IFN-ß induced the nuclear export of ID2 to form a negative feedback loop. Knocking out ID2 in human cells enhanced innate immune responses and suppressed infection by different viruses, including SARS-CoV-2. Mice with a myeloid-specific deficiency of ID2 produced more IFN-α in response to viral infection and were more resistant to viral infection than wild-type mice. Our findings not only establish ID2 as a modulator of IRF3 activation induced by TBK1 and/or IKKε but also introduce a mechanism for cross-talk between innate immunity and cell development and differentiation.


Subject(s)
COVID-19 , I-kappa B Kinase , Animals , Antiviral Agents , Humans , I-kappa B Kinase/genetics , I-kappa B Kinase/metabolism , Immunity, Innate , Inhibitor of Differentiation Protein 2 , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Mice , Phosphorylation , SARS-CoV-2
19.
Cell Rep ; 37(13): 110175, 2021 12 28.
Article in English | MEDLINE | ID: mdl-34965427

ABSTRACT

Lysine 63-linked polyubiquitin (K63-Ub) chains activate a range of cellular immune and inflammatory signaling pathways, including the mammalian antiviral response. Interferon and antiviral genes are triggered by TRAF family ubiquitin ligases that form K63-Ub chains. LGP2 is a feedback inhibitor of TRAF-mediated K63-Ub that can interfere with diverse immune signaling pathways. Our results demonstrate that LGP2 inhibits K63-Ub by association with and sequestration of the K63-Ub-conjugating enzyme, Ubc13/UBE2N. The LGP2 helicase subdomain, Hel2i, mediates protein interaction that engages and inhibits Ubc13/UBE2N, affecting control over a range of K63-Ub ligase proteins, including TRAF6, TRIM25, and RNF125, all of which are inactivated by LGP2. These findings establish a unifying mechanism for LGP2-mediated negative regulation that can modulate a variety of K63-Ub signaling pathways.


Subject(s)
Gene Expression Regulation , Lysine/metabolism , NF-kappa B/metabolism , RNA Helicases/metabolism , Ubiquitin-Conjugating Enzymes/metabolism , Ubiquitin/metabolism , Ubiquitination , Cytokines/metabolism , Humans , Interferon Regulatory Factor-3/genetics , Interferon Regulatory Factor-3/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lysine/genetics , NF-kappa B/genetics , RNA Helicases/genetics , Signal Transduction , TNF Receptor-Associated Factor 6/genetics , TNF Receptor-Associated Factor 6/metabolism , Ubiquitin-Conjugating Enzymes/genetics
20.
Cells ; 10(12)2021 12 12.
Article in English | MEDLINE | ID: mdl-34944018

ABSTRACT

Mayaro virus (MAYV) is an emerging mosquito-transmitted virus that belongs to the genus Alphavirus within the family Togaviridae. Humans infected with MAYV often develop chronic and debilitating arthralgia and myalgia. The virus is primarily maintained via a sylvatic cycle, but it has the potential to adapt to urban settings, which could lead to large outbreaks. The interferon (IFN) system is a critical antiviral response that limits replication and pathogenesis of many different RNA viruses, including alphaviruses. Here, we investigated how MAYV infection affects the induction phase of the IFN response. Production of type I and III IFNs was efficiently suppressed during MAYV infection, and mapping revealed that expression of the viral non-structural protein 2 (nsP2) was sufficient for this process. Interactome analysis showed that nsP2 interacts with DNA-directed RNA polymerase II subunit A (Rpb1) and transcription initiation factor IIE subunit 2 (TFIIE2), which are host proteins required for RNA polymerase II-mediated transcription. Levels of these host proteins were reduced by nsP2 expression and during infection by MAYV and related alphaviruses, suggesting that nsP2-mediated inhibition of host cell transcription is an important aspect of how some alphaviruses block IFN induction. The findings from this study may prove useful in design of vaccines and antivirals, which are currently not available for protection against MAYV and infection by other alphaviruses.


Subject(s)
Alphavirus/metabolism , Host-Pathogen Interactions , Interferons/metabolism , Protein Subunits/metabolism , Transcription Factors, TFII/metabolism , Viral Nonstructural Proteins/metabolism , Animals , Cell Line , Cell Nucleus/metabolism , Down-Regulation , Humans , Interferon Regulatory Factor-3/metabolism , Protein Binding , Protein Transport , RNA Polymerase II/metabolism , Transcription, Genetic
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