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1.
Cell Rep ; 40(10): 111310, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36070696

RESUMO

Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that plays a critical role in regulating antiviral signaling. cGAS binds to DNA and catalyzes the synthesis of cyclic GMP-AMP (cGAMP), which is essential for downstream signal transduction. The antiviral response is a rapid biological process; however, cGAS itself has relatively low DNA binding affinity, implying that formation of the cGAS-DNA complex requires an additional factor(s) that promotes cGAS-DNA binding, allowing efficient antiviral signal transduction. Here, we report that the Ku proteins (Ku80 and Ku70) directly interact with cGAS and positively regulate cGAS-mediated antiviral signaling. Mechanistically, we find that the interaction of the Ku proteins with cGAS significantly increases the DNA-binding affinity of cGAS and promotes cGAS condensation in the cytosol, thereby enhancing cGAS catalytic activity. Our results show that the Ku proteins are critical partners of cGAS in sensing DNA virus infection and ensuring efficient innate immune signal transduction.


Assuntos
Nucleotídeos Cíclicos , Nucleotidiltransferases , Antivirais , DNA/metabolismo , Nucleotídeos Cíclicos/metabolismo , Nucleotidiltransferases/metabolismo
2.
Front Immunol ; 13: 973089, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36059472

RESUMO

Acute lung injury(ALI)/acute respiratory distress syndrome(ARDS) is a form of acute-onset hypoxemic respiratory failure characterised by an acute, diffuse, inflammatory lung injury, and increased alveolar-capillary permeability, which is caused by a variety of pulmonary or nonpulmonary insults. Recently, aberrant mitochondria and mitochondrial DNA(mtDNA) level are associated with the development of ALI/ARDS, and plasma mtDNA level shows the potential to be a promising biomarker for clinical diagnosis and evaluation of lung injury severity. In mechanism, the mtDNA and its oxidised form, which are released from impaired mitochondria, play a crucial role in the inflammatory response and histopathological changes in the lung. In this review, we discuss mitochondrial outer membrane permeabilisation (MOMP), mitochondrial permeability transition pore(mPTP), extracellular vesicles (EVs), extracellular traps (ETs), and passive release as the principal mechanisms for the release of mitochondrial DNA into the cytoplasm and extracellular compartments respectively. Further, we explain how the released mtDNA and its oxidised form can induce inflammatory cytokine production and aggravate lung injury through the Toll-like receptor 9(TLR9) signalling, cytosolic cGAS-stimulator of interferon genes (STING) signalling (cGAS-STING) pathway, and inflammasomes activation. Additionally, we propose targeting mtDNA-mediated inflammatory pathways as a novel therapeutic approach for treating ALI/ARDS.


Assuntos
Lesão Pulmonar Aguda , Síndrome do Desconforto Respiratório , Lesão Pulmonar Aguda/metabolismo , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Humanos , Inflamação/metabolismo , Mitocôndrias/metabolismo , Nucleotidiltransferases/metabolismo , Síndrome do Desconforto Respiratório/genética
3.
Front Immunol ; 13: 887649, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36059473

RESUMO

Cancer treatment utilizing infusion therapies to enhance the patient's own immune response against the tumor have shown significant functionality in a small subpopulation of patients. Additionally, advances have been made in the utilization of nanotechnology for the treatment of disease. We have previously reported the potent effects of 3-4 daily intravenous infusions of immune modifying poly(lactic-co-glycolic acid) (PLGA) nanoparticles (IMPs; named ONP-302) for the amelioration of acute inflammatory diseases by targeting myeloid cells. The present studies describe a novel use for ONP-302, employing an altered dosing scheme to reprogram myeloid cells resulting in significant enhancement of tumor immunity. ONP-302 infusion decreased tumor growth via the activation of the cGAS/STING pathway within myeloid cells, and subsequently increased NK cell activation via an IL-15-dependent mechanism. Additionally, ONP-302 treatment increased PD-1/PD-L1 expression in the tumor microenvironment, thereby allowing for functionality of anti-PD-1 for treatment in the B16.F10 melanoma tumor model which is normally unresponsive to monotherapy with anti-PD-1. These findings indicate that ONP-302 allows for tumor control via reprogramming myeloid cells via activation of the STING/IL-15/NK cell mechanism, as well as increasing anti-PD-1 response rates.


Assuntos
Melanoma Experimental , Nanopartículas , Animais , Humanos , Imunoterapia/métodos , Interleucina-15 , Melanoma Experimental/terapia , Proteínas de Membrana/metabolismo , Células Mieloides/metabolismo , Nucleotidiltransferases/metabolismo , Microambiente Tumoral
4.
Gut Microbes ; 14(1): 2119055, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36093568

RESUMO

Studies of the gut-liver axis have enhanced our understanding of the pathophysiology of various liver diseases and the mechanisms underlying the regulation of the effectiveness of therapies. Radiotherapy (RT) is an important therapeutic option for patients with unresectable hepatocellular carcinoma (HCC). However, the role of the microbiome in regulating the response to RT remains unclear. The present study characterizes the gut microbiome of patients responsive or non-responsive to RT and investigates the molecular mechanisms underlying the differences in patient response. We collected fecal samples for 16S rRNA sequencing from a prospective longitudinal trial of 24 HCC patients receiving RT. We used fecal microbiota transplantation (FMT), flow cytometry, and transcriptome sequencing to explore the effects of dysbiosis on RT. We also examined the role of stimulator of interferon genes (STING) in RT-associated antitumor immune responses mediated by gut microbiota in STING- (Tmem173-/-) and cGAS-knockout (Mb21d1-/-) mouse models. We propose that primary resistance to RT could be attributed to the disruption of the gut microbiome. Mechanistically, gut microbiome dysbiosis impairs antitumor immune responses by suppressing antigen presentation and inhibiting effector T cell functions through the cGAS-STING-IFN-I pathway. Cyclic-di-AMP - an emerging second messenger of bacteria - may act as a STING agonist and is thus a potential target for the prediction and modulation of responses to RT in HCC patients. Our study highlights the therapeutic potential of modulating the gut microbiome in HCC patients receiving RT and provides a new strategy for the radiosensitization of liver cancer.


Assuntos
Carcinoma Hepatocelular , Microbioma Gastrointestinal , Neoplasias Hepáticas , Animais , Carcinoma Hepatocelular/radioterapia , Disbiose/terapia , Imunidade , Neoplasias Hepáticas/radioterapia , Camundongos , Nucleotidiltransferases/metabolismo , Estudos Prospectivos , RNA Ribossômico 16S/genética
5.
Pathol Oncol Res ; 28: 1610401, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36061145

RESUMO

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-mediated senescence-associated secretory phenotype (SASP) pathway has recently been identified in the suppression and promotion of cancers. However, its practical role in carcinogenesis remains to be comprehensively elucidated. Here, we describe an investigation analysing SASP activity and its correlations with DNA damage response (DDR), genomic mutations, and cell proliferation in gastric carcinogenesis among 30 cases with available endoscopic submucosal dissection (ESD) specimens of early neoplastic lesions (including low-grade dysplasia [LGD], high-grade dysplasia [HGD], and intramucosal carcinoma). The positive cells of senescence-associated ß-galactosidase staining and cGAS, STING, interferon-regulatory factor 3 (IRF3), and signal transducer and activator of transcription 6 (STAT6) expression levels using immunostaining were elevated in HGD and in cancers. Similarly, increased expression of the Fanconi anemia group D2 (FANCD2) protein, tumour suppressor p53 binding protein 1 (TP53BP1), and replication protein A (RPA2) (i.e., primary DDR factors) was detected in HGD and in cancers; these increased expression levels were closely correlated with high expression of Ki67 and minichromosome maintenance complex component 7 (MCM7) proteins. Moreover, genomic mutations in TP53 gene were detected in 56.67% of the evaluated cases (17/30) using next-generation sequencing, and positive staining was verified in HGD and in cancers. Statistical analysis revealed that cell proliferation closely correlated with the expression of DDR factors, of which TP53BP1 was positively associated with SASP factors and IRF3 was positively correlated with cell proliferation. In addition, an analysis evaluating clinical features demonstrated that STAT6-positive cases showed a longer progression-free survival time than STAT6-negative cases. Our evaluation, conducted using a limited number of specimens, suggests SASP may be prevalent in early gastric neoplastic lesions and could be activated by accelerated cell proliferation-induced DDR. The clinical significance of SASP still needs to be determined.


Assuntos
Senescência Celular , Neoplasias , Carcinogênese , Proliferação de Células/genética , Senescência Celular/genética , Dano ao DNA/genética , Humanos , Proteínas de Membrana , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo
6.
Eur J Pharmacol ; 932: 175241, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36058291

RESUMO

Organ fibrosis is accompanied by pathological angiogenesis. Discovering new ways to ameliorate pathological angiogenesis may bypass organ fibrosis. The cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway has been implicated in organ injuries and its activation inhibits endothelial proliferation. Currently, a controversy exists as to whether cGAS/STING activation exacerbates inflammation and tissue injury or mitigates damage, and whether one of these effects predominates under specific context. This study unveiled a new antifibrotic cGAS/STING signaling pathway that suppresses pathological angiogenesis in liver and kidney fibrosis. We showed that cGAS expression was induced in fibrotic liver and kidney, but suppressed in endothelial cells. cGAS genetic deletion promoted liver and kidney fibrosis and pathological angiogenesis, including occurrence of endothelial-to-mesenchymal transition. Meanwhile, cGAS deletion upregulated profibrotic Yes-associated protein (YAP) signaling in endothelial cells, which was evidenced by the attenuation of organ fibrosis in mice specifically lacking endothelial YAP. Pharmacological targeting of cGAS/STING-YAP signaling by both a small-molecule STING agonist, SR-717, and a G protein-coupled receptor (GPCR)-based antagonist that blocks the profibrotic activity of endothelial YAP, attenuated liver and kidney fibrosis. Together, our data support that activation of cGAS/STING signaling mitigates organ fibrosis and suppresses pathological angiogenesis. Further, pharmacological targeting of cGAS/STING-YAP axis exhibits the potential to alleviate liver and kidney fibrosis.


Assuntos
Células Endoteliais , Proteínas de Sinalização YAP , Monofosfato de Adenosina , Animais , Células Endoteliais/metabolismo , Fibrose , Guanosina Monofosfato , Interferons , Proteínas de Membrana/metabolismo , Camundongos , Neovascularização Patológica , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo
7.
PLoS Pathog ; 18(9): e1010316, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36103568

RESUMO

The evolutionarily successful poxviruses possess effective and diverse strategies to circumvent or overcome host defense mechanisms. Poxviruses encode many immunoregulatory proteins to evade host immunity to establish a productive infection and have unique means of inhibiting DNA sensing-dependent type 1 interferon (IFN-I) responses, a necessity given their dsDNA genome and exclusively cytoplasmic life cycle. We found that the key DNA sensing inhibition by poxvirus infection was dominant during the early stage of poxvirus infection before DNA replication. In an effort to identify the poxvirus gene products which subdue the antiviral proinflammatory responses (e.g., IFN-I response), we investigated the function of one early gene that is the known host range determinant from the highly conserved poxvirus host range C7L superfamily, myxoma virus (MYXV) M062. Host range factors are unique features of poxviruses that determine the species and cell type tropism. Almost all sequenced mammalian poxviruses retain at least one homologue of the poxvirus host range C7L superfamily. In MYXV, a rabbit-specific poxvirus, the dominant and broad-spectrum host range determinant of the C7L superfamily is the M062R gene. The M062R gene product is essential for MYXV infection in almost all cells tested from different mammalian species and specifically inhibits the function of host Sterile α Motif Domain-containing 9 (SAMD9), as M062R-null (ΔM062R) MYXV causes abortive infection in a SAMD9-dependent manner. In this study we investigated the immunostimulatory property of the ΔM062R. We found that the replication-defective ΔM062R activated host DNA sensing pathway during infection in a cGAS-dependent fashion and that knocking down SAMD9 expression attenuated proinflammatory responses. Moreover, transcriptomic analyses showed a unique feature of the host gene expression landscape that is different from the dsDNA alone-stimulated inflammatory state. This study establishes a link between the anti-neoplastic function of SAMD9 and the regulation of innate immune responses.


Assuntos
Interferon Tipo I , Myxoma virus , Infecções por Poxviridae , Poxviridae , Animais , Especificidade de Hospedeiro/genética , Humanos , Interferon Tipo I/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Macrófagos/metabolismo , Mamíferos , Monócitos/metabolismo , Myxoma virus/genética , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Poxviridae/genética , Poxviridae/metabolismo , Infecções por Poxviridae/genética , Coelhos , Transcriptoma , Vírus Vaccinia/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo
8.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 44(4): 661-667, 2022 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-36065699

RESUMO

As a DNA receptor in the cytoplasm,cyclic GMP-AMP synthase (cGAS) can recognize abnormal DNA in the cytoplasm and activate stimulator of interferon genes (STING) to regulate the immune response. The recent studies have demonstrated that this pathway plays a role in non-infectious inflammatory diseases by promoting the expression of type Ⅰ interferon and interferon-stimulated gene.This article reviews the activation and regulation of cGAS-STING pathway in multiple systems and the effect of this pathway on the occurrence and progression of non-infectious inflammatory diseases,providing theoretical reference for future application of cGAS-STING pathway-related drugs in non-infectious inflammatory diseases.


Assuntos
Doenças não Transmissíveis , Humanos , Interferons , Proteínas de Membrana/metabolismo , Nucleotídeos Cíclicos , Nucleotidiltransferases/metabolismo , Transdução de Sinais
9.
Oncoimmunology ; 11(1): 2117321, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36117525

RESUMO

The concept of exploiting tumor intrinsic deficiencies in DNA damage repair mechanisms by inhibiting compensatory DNA repair pathways is well established. For example, ATM-deficient cells show increased sensitivity to the ATR inhibitor ceralasertib. DNA damage response (DDR)-deficient cells are also more sensitive to DNA damaging agents like the DNA crosslinker pyrrolobenzodiazepine (PBD) SG-3199. However, additional antitumor benefits from targeting the DDR pathways, which could operate through the activation of the innate immune system are less well studied. DNA accumulation in the cytosol acts as an immunogenic danger signal, inducing the expression of type-I interferon (IFN) stimulated genes (ISGs) by the activation of the cGAS-STING pathway. Here, we demonstrate that ATM -/- FaDu tumor cells have higher basal expression of ISGs when compared to WT cells and respond to ceralasertib and PBD SG-3199 by inducing higher levels of ISGs in a cGAS-STING-dependent manner. We show that sensitive tumor cells treated with ceralasertib and PBD SG-3199 activate dendritic cells (DCs) via a type-I IFN-dependent mechanism. However, STING deficiency in tumor cells does not prevent DC activation, suggesting that transactivation of the STING pathway occurs within DCs. Furthermore, depletion of the cytosolic DNA exonuclease TREX1 in tumor cells increases DC activation in response to PBD SG-3199-treated tumor cells, indicating that an increase in tumor-derived cytosolic DNA may further enhance DC activation. In summary, in this study, we show that ceralasertib and PBD SG-3199 treatment not only intrinsically target tumor cells but also extrinsically increase tumor cell immunogenicity by inducing DC activation, which is enhanced in ATM-deficient cells.


Assuntos
Interferon Tipo I , Neoplasias , DNA , Dano ao DNA , Células Dendríticas/metabolismo , Exodesoxirribonucleases , Indóis , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Morfolinas , Neoplasias/genética , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Pirimidinas , Sulfonamidas
10.
Front Immunol ; 13: 949451, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35967325

RESUMO

In response to several types of bacteria, as well as pharmacological agents, neutrophils produce extracellular vesicles (EVs) and release DNA in the form of neutrophil extracellular traps (NETs). However, it is unknown whether these two neutrophil products cooperate to modulate inflammation. Consistent with vital NETosis, neutrophils challenged with S. aureus, as well as those treated with A23187, released significantly more DNA relative to untreated or fMLF-treated neutrophils, with no lysis occurring for any condition. To test the hypothesis that EVs generated during NETosis caused macrophage inflammation, we isolated and characterized EVs from A23187-treated neutrophils (A23187-EVs). A23187-EVs associated with neutrophil granule proteins, histone H3, transcription factor A, mitochondrial (TFAM), and nuclear and mitochondrial DNA (mtDNA). We showed that DNA from A23187-EVs, when transfected into macrophages, led to production of IL-6 and IFN-α2, and this response was blunted by pre-treatment with the STING inhibitor H151. Next, we confirmed that A23187-EVs were engulfed by macrophages, and showed that they induced cGAS-STING-dependent IL-6 production. In contrast, neither EVs from untreated or fMLF-treated cells exhibited pro-inflammatory activity. Although detergent-mediated lysis of A23187-EVs diminished IL-6 production, removal of surface-associated DNA with DNase I treatment had no effect, and A23187-EVs did not induce IFN-α2 production. Given these unexpected results, we investigated whether macrophage mtDNA activated the cGAS-STING signaling axis. Consistent with mitochondrial outer membrane permeabilization (MOMP), a defined mechanism of mtDNA release, we observed macrophage mitochondrial membrane depolarization, a decrease in cytosolic Bax, and a decrease in mitochondrial cytochrome c, suggesting that macrophage mtDNA may initiate this EV-dependent signaling cascade. All together, these data demonstrate that A23187-EVs behave differently than transfected NET- or EV-DNA, and that neutrophil-derived EVs could be used as a model to study NF-κB-dependent STING activation.


Assuntos
Vesículas Extracelulares , Neutrófilos , Calcimicina/metabolismo , Calcimicina/farmacologia , Cromogranina A , DNA Mitocondrial/metabolismo , Vesículas Extracelulares/metabolismo , Humanos , Inflamação/metabolismo , Interleucina-6/metabolismo , Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Neutrófilos/metabolismo , Nucleotidiltransferases/metabolismo , Staphylococcus aureus/metabolismo
11.
Proc Natl Acad Sci U S A ; 119(32): e2208317119, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35914137

RESUMO

The proper balance of synthesis, folding, modification, and degradation of proteins, also known as protein homeostasis, is vital to cellular health and function. The unfolded protein response (UPR) is activated when the mechanisms maintaining protein homeostasis in the endoplasmic reticulum become overwhelmed. However, prolonged or strong UPR responses can result in elevated inflammation and cellular damage. Previously, we discovered that the enzyme filamentation induced by cyclic-AMP (Fic) can modulate the UPR response via posttranslational modification of binding immunoglobulin protein (BiP) by AMPylation during homeostasis and deAMPylation during stress. Loss of fic in Drosophila leads to vision defects and altered UPR activation in the fly eye. To investigate the importance of Fic-mediated AMPylation in a mammalian system, we generated a conditional null allele of Fic in mice and characterized the effect of Fic loss on the exocrine pancreas. Compared to controls, Fic-/- mice exhibit elevated serum markers for pancreatic dysfunction and display enhanced UPR signaling in the exocrine pancreas in response to physiological and pharmacological stress. In addition, both fic-/- flies and Fic-/- mice show reduced capacity to recover from damage by stress that triggers the UPR. These findings show that Fic-mediated AMPylation acts as a molecular rheostat that is required to temper the UPR response in the mammalian pancreas during physiological stress. Based on these findings, we propose that repeated physiological stress in differentiated tissues requires this rheostat for tissue resilience and continued function over the lifetime of an animal.


Assuntos
AMP Cíclico , Proteínas de Drosophila , Drosophila melanogaster , Estresse do Retículo Endoplasmático , Nucleotidiltransferases , Estresse Fisiológico , Resposta a Proteínas não Dobradas , Alelos , Animais , AMP Cíclico/metabolismo , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Camundongos , Nucleotidiltransferases/deficiência , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Pâncreas/efeitos dos fármacos , Pâncreas/enzimologia , Pâncreas/metabolismo , Pâncreas/fisiopatologia , Estresse Fisiológico/efeitos dos fármacos , Resposta a Proteínas não Dobradas/efeitos dos fármacos
12.
Int Immunopharmacol ; 111: 109101, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35940076

RESUMO

Cisplatin, as a commonly used anticancer drug, can easily lead to acute kidney injury (AKI), and has received more and more attention in clinical practice. ß-hydroxybutyric acid (BHB) is a metabolite in the body and acts as an inhibitor of oxidative stress and NLRP3 inflammasome, reducing inflammatory responses and apoptosis. However, the role of BHB in cisplatin-induced AKI is currently not fully elucidated. In this study, C57BL/6 male mice were randomly divided into normal control group, cisplatin-induced AKI group and AKI with BHB treatment group. Compared to the control, cisplatin-treated mice exhibited high level of serum creatinine, blood urea nitrogen and severe tubular injury, which accompanied with significantly increased expression level of NLRP3, IL-1ß, IL-18, BAX, cleaved-caspase 3, as well as aggravated oxidative stress and renal tubular cell apoptosis. However, these changes were significantly improved in that of BHB treatment. In vitro, our study showed that the expression of cleaved-caspase3, IL-1ß and IL-18 were significantly increased in human proximal tubular epithelial cell line (HK-2) treated with cisplatin compared with the control group, while decreased in cells treated with BHB. Furthermore, a significantly increased expression of cGAS and STING in HK-2 cells treated with cisplatin were found, whereas notably decreased in cells treated with BHB. This data indicates that BHB protects against cisplatin-induced AKI and renal tubular damage mediated by NLRP3 inflammasome and cGAS-STING pathway.


Assuntos
Injúria Renal Aguda , Inflamassomos , Ácido 3-Hidroxibutírico , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/metabolismo , Animais , Cisplatino/efeitos adversos , Humanos , Inflamassomos/metabolismo , Interleucina-18/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Nucleotidiltransferases/metabolismo , Estresse Oxidativo
13.
Immunity ; 55(8): 1386-1401.e10, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35931086

RESUMO

Deleterious somatic mutations in DNA methyltransferase 3 alpha (DNMT3A) and TET mehtylcytosine dioxygenase 2 (TET2) are associated with clonal expansion of hematopoietic cells and higher risk of cardiovascular disease (CVD). Here, we investigated roles of DNMT3A and TET2 in normal human monocyte-derived macrophages (MDM), in MDM isolated from individuals with DNMT3A or TET2 mutations, and in macrophages isolated from human atherosclerotic plaques. We found that loss of function of DNMT3A or TET2 resulted in a type I interferon response due to impaired mitochondrial DNA integrity and activation of cGAS signaling. DNMT3A and TET2 normally maintained mitochondrial DNA integrity by regulating the expression of transcription factor A mitochondria (TFAM) dependent on their interactions with RBPJ and ZNF143 at regulatory regions of the TFAM gene. These findings suggest that targeting the cGAS-type I IFN pathway may have therapeutic value in reducing risk of CVD in patients with DNMT3A or TET2 mutations.


Assuntos
Doenças Cardiovasculares , DNA Metiltransferase 3A/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/metabolismo , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/genética , Dioxigenases/genética , Humanos , Interferons/metabolismo , Macrófagos/metabolismo , Mitocôndrias/genética , Mutação/genética , Nucleotidiltransferases/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Transativadores/metabolismo
14.
Neuropharmacology ; 217: 109206, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35926582

RESUMO

Neuroinflammation plays a vital role in the development of neuropathic pain and is mediated mainly by microglia. Suppressing microglial M1-polarization attenuates neuropathic pain. Recently, the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has emerged as a key mediator of inflammation and shows potential in modulating microglial polarization. In this study, we evaluated whether cGAS-STING is a potential therapeutic target. Spared nerve injury (SNI) surgery was conducted in adult male rats to establish a neuropathic pain model. We showed that SNI promoted microglial M1-polarization and induced cGAS-STING pathway activation in the spinal cord. Double-label immunofluorescence assays showed that cGAS-STING activation mainly occurred in neurons and microglia but not astrocytes. We further conducted in vitro experiments using BV-2 microglial cells. The results showed that LPS-induced microglial M1-polarization was accompanied by cGAS-STING pathway activation, but cGAS-STING inhibition by antagonists suppressed LPS-induced microglial M1-polarization. In vivo, we also showed that a cGAS antagonist and a STING antagonist suppressed the microglial M1-polarization and ameliorated the mechanical allodynia induced by SNI. These findings suggested that the cGAS-STING pathway might be a potential therapeutic target for treating neuropathic pain. However, further research is warranted to verify our findings in female rodents.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Membrana , Microglia , Neuralgia , Nucleotidiltransferases , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Lipopolissacarídeos , Masculino , Proteínas de Membrana/metabolismo , Microglia/metabolismo , Neuralgia/tratamento farmacológico , Neuralgia/metabolismo , Nucleotidiltransferases/metabolismo , Ratos , Transdução de Sinais , Medula Espinal/metabolismo
15.
Nat Commun ; 13(1): 4822, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35973990

RESUMO

Sensing of cytosolic DNA of microbial or cellular/mitochondrial origin by cGAS initiates innate immune responses via the adaptor protein STING. It remains unresolved how the activity of STING is balanced between a productive innate immune response and induction of autoimmunity. Here we show that interferon regulatory factor 8 (IRF8) is essential for efficient activation of STING-mediated innate immune responses in monocytes. This function of IRF8 is independent of its transcriptional role in monocyte differentiation. In uninfected cells, IRF8 remains inactive via sequestration of its IRF-associated domain by its N- and C-terminal tails, which reduces its association with STING. Upon triggering the DNA sensing pathway, IRF8 is phosphorylated at Serine 151 to allow its association with STING via the IRF-associated domain. This is essential for STING polymerization and TBK1-mediated STING and IRF3 phosphorylation. Consistently, IRF8-deficiency impairs host defense against the DNA virus HSV-1, and blocks DNA damage-induced cellular senescence. Bone marrow-derived mononuclear cells which have an autoimmune phenotype due to deficiency of Trex1, respond to IRF-8 deletion with reduced pro-inflammatory cytokine production. Peripheral blood mononuclear cells from systemic lupus erythematosus patients are characterized by elevated phosphorylation of IRF8 at the same Serine residue we find to be important in STING activation, and in these cells STING is hyper-active. Taken together, the transcription-independent function of IRF8 we describe here appears to mediate STING activation and represents an important regulatory step in the cGAS/STING innate immune pathway in monocytes.


Assuntos
Leucócitos Mononucleares , Monócitos , DNA , Imunidade Inata/genética , Fator Regulador 3 de Interferon/metabolismo , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Leucócitos Mononucleares/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Monócitos/metabolismo , Nucleotidiltransferases/metabolismo , Serina
16.
Biochem Biophys Res Commun ; 623: 181-188, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35921710

RESUMO

Type I interferon pathway is a crucial component of innate immune signaling upon pathogen infection or endogenous instability. An imbalance of type I interferon can lead to many diseases, such as autoimmune diseases and inflammatory diseases. Meanwhile, the side effects of clinical drugs on type I interferon signaling may result in impaired outcomes in clinical treatment, especially in cancer immunotherapy which is associated with type I interferon signaling. Here, we found that sorafenib, an FDA-approved drug for HCC chemotherapy, suppresses both DNA- and RNA-sensing mediated type I interferon pathway. Mechanistically, sorafenib treatment induces the autophagic degradation of MAVS, cGAS, TBK1, and IRF3, and attenuates the signaling transduction. In addition, sorafenib also inhibits the recruiting of STING or MAVS with TBK1 and IRF3. This work reveals the negative role of sorafenib in the regulation of type I interferon pathway. Sorafenib treatment is not only a potential drug for autoimmune disease and inflammation diseases, but also needs to be noticed in HCC chemotherapy.


Assuntos
Carcinoma Hepatocelular , Interferon Tipo I , Neoplasias Hepáticas , Humanos , Imunidade Inata , Fator Regulador 3 de Interferon/metabolismo , Interferon Tipo I/metabolismo , Nucleotidiltransferases/metabolismo , Proteínas Serina-Treonina Quinases , Sorafenibe/farmacologia
17.
Am J Physiol Cell Physiol ; 323(3): C907-C919, 2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35938680

RESUMO

We sought to determine the effects of long-term voluntary wheel running on markers of long interspersed nuclear element-1 (L1) in skeletal muscle, liver, and the hippocampus of female rats. In addition, markers of the cGAS-STING DNA-sensing pathway that results in inflammation were interrogated. Female Lewis rats (n = 34) were separated into one of three groups including a 6-mo-old group to serve as a young comparator group (CTL, n = 10), a group that had access to a running wheel for voluntary wheel running (EX, n = 12), and an age-matched group that did not (SED, n = 12). Both SED and EX groups were carried out from 6 mo to 15 mo of age. There were no significant differences in L1 mRNA expression for any of the tissues between groups. Methylation of the L1 promoter in the soleus and hippocampus was significantly higher in SED and EX than in CTL group (P < 0.05). ORF1p expression was higher in older SED and EX rats than in CTL rats for every tissue (P < 0.05). There were no differences between groups for L1 mRNA or cGAS-STING pathway markers. Our results suggest there is an increased ORF1 protein expression across tissues with aging that is not mitigated by voluntary wheel running. In addition, although previous data imply that L1 methylation changes may play a role in acute exercise for L1 RNA expression, this does not seem to occur during extended periods of voluntary wheel running.


Assuntos
Atividade Motora , Condicionamento Físico Animal , Animais , Biomarcadores/metabolismo , Encéfalo/metabolismo , Feminino , Fígado/metabolismo , Atividade Motora/fisiologia , Músculo Esquelético/metabolismo , Nucleotidiltransferases/metabolismo , Condicionamento Físico Animal/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos Lew
18.
Crit Rev Oncol Hematol ; 178: 103780, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35953012

RESUMO

The activation of innate immune response after the engagement of dsDNA is an evolutionarily preserved sophisticated strategy against invading microbial pathogens. cGAS has been identified as one of the major dsDNA sensor present in the cytoplasm which catalyzes the synthesis of a cyclic dinucleotide 2'3'cGAMP, as the secondary messenger that binds and activates the downstream stimulator of interferon (IFN) genes (STING) for subsequent production of type 1 IFNs and other inflammatory genes. Recent progress in the mechanical understanding of cGAS/STING signalling has unveiled its intricate role in tumor progression and metastasis. In this review, we specifically focus on new developments concerning the role of cGAS/STING signalling in regulating antitumorigenesis and tumorigenesis.


Assuntos
Proteínas de Membrana , Neoplasias , DNA , Humanos , Imunidade Inata/genética , Interferons , Proteínas de Membrana/genética , Neoplasias/genética , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo
19.
Proc Natl Acad Sci U S A ; 119(33): e2200285119, 2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-35939686

RESUMO

Kaposi's sarcoma-associated herpesvirus (KSHV) inhibitor of cyclic GMP-AMP synthase (cGAS) (KicGAS) encoded by ORF52 is a conserved major tegument protein of KSHV and the first reported viral inhibitor of cGAS. In our previous study, we found that KicGAS is highly oligomerized in solution and that oligomerization is required for its cooperative DNA binding and for inhibiting DNA-induced phase separation and activation of cGAS. However, how KicGAS oligomerizes remained unclear. Here, we present the crystal structure of KicGAS at 2.5 Å resolution, which reveals an "L"-shaped molecule with each arm of the L essentially formed by a single α helix (α1 and α2). Antiparallel dimerization of α2 helices from two KicGAS molecules leads to a unique "Z"-shaped dimer. Surprisingly, α1 is also a dimerization domain. It forms a parallel dimeric leucine zipper with the α1 from a neighboring dimer, leading to the formation of an infinite chain of KicGAS dimers. Residues involved in leucine zipper dimer formation are among the most conserved residues across ORF52 homologs of gammaherpesviruses. The self-oligomerization increases the valence and cooperativity of interaction with DNA. The resultant multivalent interaction is critical for the formation of liquid condensates with DNA and consequent sequestration of DNA from being sensed by cGAS, explaining its role in restricting cGAS activation. The structure presented here not only provides a mechanistic understanding of the function of KicGAS but also informs a molecular target for rational design of antivirals against KSHV and related viruses.


Assuntos
Herpesvirus Humano 8 , Nucleotidiltransferases , Proteínas Estruturais Virais , Herpesvirus Humano 8/metabolismo , Humanos , Nucleotidiltransferases/metabolismo , Domínios Proteicos , Multimerização Proteica , Proteínas Estruturais Virais/química
20.
J Immunol Res ; 2022: 7978042, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35983076

RESUMO

Background: The cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) plays critical functions in innate immune responses via the production of the second messenger cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), which stimulates the adaptor stimulator of interferon genes (STING). However, the clinical relevance and prognostic value of the cGAS-STING pathway in human cancers remains largely unexplored. Methods: A gene signature related to the cGAS-STING score was identified. The pan-cancer landscape of cGAS-STING expression was calculated using the RNAseq data acquired from the TCGA cohort. Tumor-infiltrating immune cells (TIICs) were determined by the ssGSEA method. Kaplan-Meier curves, Cox regression analyses, and the area under the curve (AUC) were employed to decipher the predictive value of cGAS-STING risk score and TIICs across several human cancers. Results: Most tumor tissues displayed a higher cGAS-STING score compared with their corresponding nontumor tissues, except for prostate adenocarcinoma (PRAD) and uterine corpus endometrial carcinoma (UCEC). Higher cGAS-STING score was closely associated with poor clinical outcome of kidney renal clear cell carcinoma (KIRC) and kidney renal papillary cell carcinoma (KIRP), whereas the cGAS-STING score predicted a better prognosis in pheochromocytoma and paraganglioma (PCPG). Enrichment analysis showed that cGAS-STING was profoundly implicated in diverse immune-related pathways in KIRC, KIRP, and PCPG. Significant positive correlations were noticed between cGAS-STING score and TIICs, including activated CD8+ T cells, activated CD4+ T cells, monocytes, and mast cells. Finally, the cGAS-STING score was revealed to be an independent prognostic factor for KIRC patients and possessed a strong predictive power for the prognostic evaluation of KIRC and KIRP patients. Conclusions: We constructed a cGAS-STING gene signature to predict survival and tumor immunity across human cancers, which can serve as a novel prognostic indicator and therapeutic target, especially in KIRC and KIRP.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Proteínas de Membrana , Nucleotidiltransferases , Carcinoma de Células Renais/genética , DNA , Humanos , Neoplasias Renais/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Fatores de Risco , Transdução de Sinais
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