ABSTRACT
Bacterial small molecule metabolites such as adenosine-diphosphate-d-glycero-ß-d-manno-heptose (ADP-heptose) and their derivatives act as effective innate immune agonists in mammals. We show that functional nucleotide-diphosphate-heptose biosynthetic enzymes (HBEs) are distributed widely in bacteria, archaea, eukaryotes, and viruses. We identified a conserved STTR5 motif as a hallmark of heptose nucleotidyltransferases that can synthesize not only ADP-heptose but also cytidine-diphosphate (CDP)- and uridine-diphosphate (UDP)-heptose. Both CDP- and UDP-heptoses are agonists that trigger stronger alpha-protein kinase 1 (ALPK1)-dependent immune responses than ADP-heptose in human and mouse cells and mice. We also produced ADP-heptose in archaea and verified its innate immune agonist functions. Hence, the ß-d-manno-heptoses are cross-kingdom, small-molecule, pathogen-associated molecular patterns that activate the ALPK1-dependent innate immune signaling cascade.
Subject(s)
Heptoses , Immunity, Innate , Animals , Mice , Humans , Nucleotidyltransferases/metabolism , Archaea/immunology , Bacteria , Amino Acid MotifsABSTRACT
Aberrant activation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway causes autoimmunity in humans and mice; however, the exact mechanism by which the cGAS-STING pathway initiates adaptive immunity and tissue pathology is still not fully understood. Here, we used a cGAS knockin (KI) mouse model that develops systemic autoimmunity. In the lungs of cGAS-KI mice, blood vessels were enclosed by organized lymphoid tissues that resemble tertiary lymphoid structures (TLSs). Cell-intrinsic cGAS induction promoted up-regulation of CCR5 in CD8+ T cells and led to CCL5 production in vascular endothelial cells. Peripheral CD8+ T cells were recruited to the lungs and produced CXCL13 and interferon-γ. The latter triggered endothelial cell death, potentiated CCL5 production, and was essential for TLS establishment. Blocking CCL5 or CCR5, or depleting CD8+ T cells, impaired TLS formation. cGAS-mediated TLS formation also enhanced humoral and antitumor responses. These data demonstrate that cGAS signaling drives a specialized lymphoid structure that underlies autoimmune tissue pathology.
Subject(s)
CD8-Positive T-Lymphocytes , Endothelial Cells , Nucleotidyltransferases , Tertiary Lymphoid Structures , Animals , Nucleotidyltransferases/immunology , Nucleotidyltransferases/genetics , Nucleotidyltransferases/metabolism , Mice , Endothelial Cells/immunology , Tertiary Lymphoid Structures/immunology , CD8-Positive T-Lymphocytes/immunology , Chemokine CCL5/immunology , Chemokine CCL5/genetics , Mice, Inbred C57BL , Mice, Transgenic , Signal Transduction/immunology , Receptors, CCR5/immunology , Receptors, CCR5/genetics , Receptors, CCR5/metabolism , Autoimmunity/immunologyABSTRACT
Photothermal, photodynamic and sonodynamic cancer therapies offer opportunities for precise tumor ablation and reduce side effects. The cyclic guanylate adenylate synthase-stimulator of interferon genes (cGAS-STING) pathway has been considered a potential target to stimulate the immune system in patients and achieve a sustained immune response. Combining photothermal, photodynamic and sonodynamic therapies with cGAS-STING agonists represents a newly developed cancer treatment demonstrating noticeable innovation in its impact on the immune system. Recent reviews have concentrated on diverse materials and their function in cancer therapy. In this review, we focus on the molecular mechanism of photothermal, photodynamic and sonodynamic cancer therapies and the connected role of cGAS-STING agonists in treating cancer.
Subject(s)
Membrane Proteins , Neoplasms , Nucleotidyltransferases , Photochemotherapy , Humans , Neoplasms/therapy , Neoplasms/drug therapy , Neoplasms/metabolism , Nucleotidyltransferases/metabolism , Membrane Proteins/metabolism , Photochemotherapy/methods , Signal Transduction/drug effects , Animals , Ultrasonic Therapy/methods , Photosensitizing Agents/pharmacology , Photosensitizing Agents/therapeutic use , Photosensitizing Agents/chemistryABSTRACT
Chronic obstructive pulmonary disease(COPD) is a gradually worsening and fatal heterogeneous lung disease characterized by airflow limitation and increasingly decline in lung function. Currently, it is one of the leading causes of death worldwide. The consistent feature of COPD is airway inflammation. Several inflammatory factors are known to be involved in COPD pathogenesis; however, anti-inflammatory therapy is not the first-line treatment for COPD. Although bronchodilators, corticosteroids and roflumilast could improve airflow and control symptoms, they could not reverse the disease. The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway plays an important novel role in the immune system and has been confirmed to be a key mediator of inflammation during infection, cellular stress, and tissue damage. Recent studies have emphasized that abnormal activation of cGAS-STING contributes to COPD, providing a direction for new treatments that we urgently need to develop. Here, we focused on the cGAS-STING pathway, providing insight into its molecular mechanism and summarizing the current knowledge on the role of the cGAS-STING pathway in COPD. Moreover, we explored antagonists of cGAS and STING to identify potential therapeutic strategies for COPD that target the cGAS-STING pathway.
Subject(s)
Membrane Proteins , Nucleotidyltransferases , Pulmonary Disease, Chronic Obstructive , Signal Transduction , Pulmonary Disease, Chronic Obstructive/drug therapy , Pulmonary Disease, Chronic Obstructive/metabolism , Humans , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/antagonists & inhibitors , Membrane Proteins/metabolism , Membrane Proteins/antagonists & inhibitors , Signal Transduction/drug effects , Animals , Molecular Targeted Therapy/methodsABSTRACT
The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway is one of the fundamental mechanisms of the body's defense, which responds to the abnormal presence of double-stranded DNA in the cytoplasm to establish an effective natural immune response. In addition to detecting microbial infections, the cGAS pathway may be triggered by any cytoplasmic DNA, which is absent from the normal cytoplasm, and only conditions such as senescence and mitochondrial stress can lead to its leakage and cause sterile inflammation. A growing body of research has shown that the cGAS-STING pathway is strongly associated with sterile inflammation. In this study, we reviewed the regulatory mechanisms and biological functions of the cGAS-STING pathway through its involvement in aseptic inflammation in liver disease, kidney disease, and cellular senescence.
Subject(s)
Cellular Senescence , Kidney Diseases , Liver Diseases , Membrane Proteins , Nucleotidyltransferases , Signal Transduction , Humans , Nucleotidyltransferases/metabolism , Cellular Senescence/immunology , Membrane Proteins/metabolism , Kidney Diseases/immunology , Kidney Diseases/metabolism , Kidney Diseases/pathology , Animals , Liver Diseases/immunology , Liver Diseases/metabolismABSTRACT
The double-stranded DNA (dsDNA) sensor STING has been increasingly implicated in responses to "sterile" endogenous threats and pathogens without nominal DNA or cyclic di-nucleotide stimuli. Previous work showed an endoplasmic reticulum (ER) stress response, known as the unfolded protein response (UPR), activates STING. Herein, we sought to determine if ER stress generated a STING ligand, and to identify the UPR pathways involved. Induction of IFN-ß expression following stimulation with the UPR inducer thapsigargin (TPG) or oxygen glucose deprivation required both STING and the dsDNA-sensing cyclic GMP-AMP synthase (cGAS). Furthermore, TPG increased cytosolic mitochondrial DNA, and immunofluorescence visualized dsDNA punctae in murine and human cells, providing a cGAS stimulus. N-acetylcysteine decreased IFN-ß induction by TPG, implicating reactive oxygen species (ROS). However, mitoTEMPO, a mitochondrial oxidative stress inhibitor did not impact TPG-induced IFN. On the other hand, inhibiting the inositol requiring enzyme 1 (IRE1) ER stress sensor and its target transcription factor XBP1 decreased the generation of cytosolic dsDNA. iNOS upregulation was XBP1-dependent, and an iNOS inhibitor decreased cytosolic dsDNA and IFN-ß, implicating ROS downstream of the IRE1-XBP1 pathway. Inhibition of the PKR-like ER kinase (PERK) pathway also attenuated cytoplasmic dsDNA release. The PERK-regulated apoptotic factor Bim was required for both dsDNA release and IFN-ß mRNA induction. Finally, XBP1 and PERK pathways contributed to cytosolic dsDNA release and IFN-induction by the RNA virus, Vesicular Stomatitis Virus (VSV). Together, our findings suggest that ER stressors, including viral pathogens without nominal STING or cGAS ligands such as RNA viruses, trigger multiple canonical UPR pathways that cooperate to activate STING and downstream IFN-ß via mitochondrial dsDNA release.
Subject(s)
Cytosol , Endoplasmic Reticulum Stress , Interferon-beta , Membrane Proteins , Nucleotidyltransferases , Unfolded Protein Response , Humans , Animals , Mice , Nucleotidyltransferases/metabolism , Cytosol/metabolism , Membrane Proteins/metabolism , Membrane Proteins/genetics , Interferon-beta/metabolism , DNA/metabolism , Protein Serine-Threonine Kinases/metabolism , Signal Transduction , eIF-2 Kinase/metabolism , Endoribonucleases/metabolism , X-Box Binding Protein 1/metabolism , X-Box Binding Protein 1/genetics , Thapsigargin/pharmacology , Reactive Oxygen Species/metabolism , Transcriptional Activation , DNA, Mitochondrial/metabolismABSTRACT
Immune checkpoint inhibitor (ICI)-induced myocarditis involves intensive immune/inflammation activation; however, its molecular basis is unclear. Here, we show that gasdermin-E (GSDME), a gasdermin family member, drives ICI-induced myocarditis. Pyroptosis mediated by GSDME, but not the canonical GSDMD, is activated in myocardial tissue of mice and cancer patients with ICI-induced myocarditis. Deficiency of GSDME in male mice alleviates ICI-induced cardiac infiltration of T cells, macrophages, and monocytes, as well as mitochondrial damage and inflammation. Restoration of GSDME expression specifically in cardiomyocytes, rather than myeloid cells, in GSDME-deficient mice reproduces ICI-induced myocarditis. Mechanistically, quantitative proteomics reveal that GSDME-dependent pyroptosis promotes cell death and mitochondrial DNA release, which in turn activates cGAS-STING signaling, triggering a robust interferon response and myocardial immune/inflammation activation. Pharmacological blockade of GSDME attenuates ICI-induced myocarditis and improves long-term survival in mice. Our findings may advance the understanding of ICI-induced myocarditis and suggest that targeting the GSDME-cGAS-STING-interferon axis may help prevent and manage ICI-associated myocarditis.
Subject(s)
Immune Checkpoint Inhibitors , Membrane Proteins , Myocarditis , Nucleotidyltransferases , Pyroptosis , Animals , Myocarditis/immunology , Myocarditis/pathology , Myocarditis/chemically induced , Myocarditis/metabolism , Membrane Proteins/metabolism , Membrane Proteins/genetics , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/adverse effects , Mice , Male , Humans , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Signal Transduction , Mice, Inbred C57BL , Mice, Knockout , DNA, Mitochondrial/metabolism , DNA, Mitochondrial/genetics , Female , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/pathology , Myocytes, Cardiac/drug effects , Intracellular Signaling Peptides and Proteins/metabolism , Intracellular Signaling Peptides and Proteins/genetics , Phosphate-Binding Proteins/metabolism , Phosphate-Binding Proteins/genetics , GasderminsABSTRACT
53BP1 nucleates the anti-end resection machinery at DNA double-strand breaks, thereby countering BRCA1 activity. Loss of 53BP1 leads to DNA end processing and homologous recombination in BRCA1-deficient cells. Consequently, BRCA1-mutant tumors, typically sensitive to PARP inhibitors (PARPi), become resistant in the absence of 53BP1. Here, we demonstrate that the 'leaky' DNA end resection in the absence of 53BP1 results in increased micronuclei and cytoplasmic double-stranded DNA, leading to activation of the cGAS-STING pathway and pro-inflammatory signaling. This enhances CD8+ T cell infiltration, activates macrophages and natural killer cells, and impedes tumor growth. Loss of 53BP1 correlates with a response to immune checkpoint blockade (ICB) and improved overall survival. Immunohistochemical assessment of 53BP1 in two malignancies, high grade serous ovarian cancer and pancreatic ductal adenocarcinoma, which are refractory to ICBs, reveals that lower 53BP1 levels correlate with an increased adaptive and innate immune response. Finally, BRCA1-deficient tumors that develop resistance to PARPi due to the loss of 53BP1 are susceptible to ICB. Therefore, we conclude that 53BP1 is critical for tumor immunogenicity and underpins the response to ICB. Our results support including 53BP1 expression as an exploratory biomarker in ICB trials for malignancies typically refractory to immunotherapy.
Subject(s)
Membrane Proteins , Nucleotidyltransferases , Ovarian Neoplasms , Pancreatic Neoplasms , Tumor Suppressor p53-Binding Protein 1 , Tumor Suppressor p53-Binding Protein 1/metabolism , Tumor Suppressor p53-Binding Protein 1/genetics , Female , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Humans , Animals , Ovarian Neoplasms/immunology , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Ovarian Neoplasms/metabolism , Pancreatic Neoplasms/immunology , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/metabolism , Mice , Cell Line, Tumor , DNA Breaks, Double-Stranded , BRCA1 Protein/metabolism , BRCA1 Protein/genetics , Signal Transduction , CD8-Positive T-Lymphocytes/immunology , Immune Checkpoint Inhibitors/therapeutic use , Immune Checkpoint Inhibitors/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use , Mice, Inbred C57BL , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Mice, Knockout , Carcinoma, Pancreatic Ductal/immunology , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/pathology , Immunity, InnateABSTRACT
Senataxin is an evolutionarily conserved DNA/RNA helicase, whose dysfunctions are linked to neurodegeneration and cancer. A main activity of this protein is the removal of R-loops, which are nucleic acid structures capable to promote DNA damage and replication stress. Here we found that Senataxin deficiency causes the release of damaged DNA into extranuclear bodies, called micronuclei, triggering the massive recruitment of cGAS, the apical sensor of the innate immunity pathway, and the downstream stimulation of interferon genes. Such cGAS-positive micronuclei are characterized by defective membrane envelope and are particularly abundant in cycling cells lacking Senataxin, but not after exposure to a DNA breaking agent or in absence of the tumor suppressor BRCA1 protein, a partner of Senataxin in R-loop removal. Micronuclei with a discontinuous membrane are normally cleared by autophagy, a process that we show is impaired in Senataxin-deficient cells. The formation of Senataxin-dependent inflamed micronuclei is promoted by the persistence of nuclear R-loops stimulated by the DSIF transcription elongation complex and the engagement of EXO1 nuclease activity on nuclear DNA. Coherently, high levels of EXO1 result in poor prognosis in a subset of tumors lacking Senataxin expression. Hence, R-loop homeostasis impairment, together with autophagy failure and unscheduled EXO1 activity, elicits innate immune response through micronuclei formation in cells lacking Senataxin.
Subject(s)
Autophagy , DNA Damage , DNA Helicases , Inflammation , Multifunctional Enzymes , Nucleotidyltransferases , R-Loop Structures , RNA Helicases , Autophagy/genetics , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Multifunctional Enzymes/metabolism , Multifunctional Enzymes/genetics , DNA Helicases/metabolism , DNA Helicases/genetics , DNA Helicases/deficiency , RNA Helicases/metabolism , RNA Helicases/genetics , Humans , Animals , Inflammation/pathology , Inflammation/metabolism , Inflammation/genetics , Mice , BRCA1 Protein/metabolism , BRCA1 Protein/genetics , BRCA1 Protein/deficiency , Exodeoxyribonucleases/metabolism , Exodeoxyribonucleases/genetics , Immunity, Innate , DNA Repair Enzymes/metabolism , DNA Repair Enzymes/genetics , DNA Repair Enzymes/deficiency , PhosphoproteinsABSTRACT
The cyclic GMP-AMP synthase (cGAS), a prominent intracellular DNA sensor in mammalian cells, controls the innate immune response and the stimulator of interferon genes (STING)-mediated synthesis of pro-inflammatory cytokines, such as type-I interferon (IFN-I). For decades, IFN-I has been hypothesized to be essential in the development of systemic lupus erythematosus (SLE), a chronic multisystem autoimmunity characterized by immune complex (IC) deposition in small vessels. Recent findings revealed that the activation of the cGAS-STING pathway by self-DNA would propagate the autoimmune responses via upregulating IFN-I production in SLE. In this review, we aimed to provide a comprehensive outlook of the role of the cGAS-STING pathway in SLE pathobiology, as well as, a better understanding of current therapeutic opportunities targeting this axis.
Subject(s)
Lupus Erythematosus, Systemic , Membrane Proteins , Nucleotidyltransferases , Signal Transduction , Humans , Lupus Erythematosus, Systemic/immunology , Lupus Erythematosus, Systemic/metabolism , Lupus Erythematosus, Systemic/drug therapy , Nucleotidyltransferases/metabolism , Membrane Proteins/metabolism , Animals , Autoimmunity , Interferon Type I/metabolism , Interferon Type I/immunology , Molecular Targeted Therapy , Immunity, InnateABSTRACT
The cGAS (cyclic GMP-AMP synthase)-STING (stimulator of interferon genes) pathway promotes antitumor immune responses by sensing cytosolic DNA fragments leaked from nucleus and mitochondria. Herein, we designed a highly charged ruthenium photosensitizer (Ru1) with a ß-carboline alkaloid derivative as the ligand for photo-activating of the cGAS-STING pathway. Due to the formation of multiple non-covalent intermolecular interactions, Ru1 can self-assemble into carrier-free nanoparticles (NPs). By incorporating the triphenylphosphine substituents, Ru1 can target and photo-damage mitochondrial DNA (mtDNA) to cause the cytoplasmic DNA leakage to activate the cGAS-STING pathway. Finally, Ru1 NPs show potent antitumor effects and elicit intense immune responses in vivo. In conclusion, we report the first self-assembling mtDNA-targeted photosensitizer, which can effectively activate the cGAS-STING pathway, thus providing innovations for the design of new photo-immunotherapeutic agents.
Subject(s)
Antineoplastic Agents , Immunotherapy , Membrane Proteins , Nucleotidyltransferases , Photosensitizing Agents , Ruthenium , Photosensitizing Agents/chemistry , Photosensitizing Agents/pharmacology , Photosensitizing Agents/chemical synthesis , Humans , Nucleotidyltransferases/metabolism , Membrane Proteins/metabolism , Animals , Ruthenium/chemistry , Ruthenium/pharmacology , Mice , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/chemical synthesis , Molecular Structure , Dose-Response Relationship, Drug , Nanoparticles/chemistry , Structure-Activity Relationship , Drug Screening Assays, Antitumor , DNA, Mitochondrial/metabolism , Cell Proliferation/drug effects , Cell Line, Tumor , Neoplasms/drug therapy , Neoplasms/pathologyABSTRACT
Replication stress compromises genomic integrity. Fork blocking lesions such as those induced by cisplatin and other chemotherapeutic agents arrest replication forks. Repriming downstream of these lesions represents an important mechanism of replication restart, however the single stranded DNA (ssDNA) gaps left behind, unless efficiently filled, can serve as entry point for nucleases. Nascent strand gaps can be repaired by BRCA-mediated homology repair. Alternatively, gaps can also be filled by translesion synthesis (TLS) polymerases. How these events are regulated is still not clear. Here, we show that PARP10, a poorly-characterized mono-ADP-ribosyltransferase, is recruited to nascent strand gaps to promote their repair. PARP10 interacts with the ubiquitin ligase RAD18 and recruits it to these structures, resulting in the ubiquitination of the replication factor PCNA. PCNA ubiquitination, in turn, recruits the TLS polymerase REV1 for gap filling. We show that PARP10 recruitment to gaps and the subsequent REV1-mediated gap filling requires both the catalytic activity of PARP10, and its ability to interact with PCNA. We moreover show that PARP10 is hyperactive in BRCA-deficient cells, and its inactivation potentiates gap accumulations and cytotoxicity in these cells. Our work uncovers PARP10 as a regulator of ssDNA gap filling, which promotes genomic stability in BRCA-deficient cells.
Subject(s)
DNA Repair , DNA Replication , DNA, Single-Stranded , DNA-Binding Proteins , Poly(ADP-ribose) Polymerases , Proliferating Cell Nuclear Antigen , Ubiquitin-Protein Ligases , Ubiquitination , Humans , Proliferating Cell Nuclear Antigen/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitin-Protein Ligases/genetics , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , DNA, Single-Stranded/metabolism , DNA, Single-Stranded/genetics , Poly(ADP-ribose) Polymerases/metabolism , Poly(ADP-ribose) Polymerases/genetics , DNA Damage , BRCA2 Protein/metabolism , BRCA2 Protein/genetics , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , BRCA1 Protein/metabolism , BRCA1 Protein/genetics , Cell Line, Tumor , HEK293 Cells , Translesion DNA Synthesis , DNA-Directed DNA Polymerase , Proto-Oncogene ProteinsABSTRACT
Accumulating evidence supports the concept that DNA damage response targeted therapies can improve antitumor immune response by increasing the immunogenicity of tumor cells and improving the tumor immune microenvironment. Ataxia telangiectasia mutated (ATM) is a core component of the DNA repair system. Although the ATM gene has a significant mutation rate in many human cancers, including colorectal, prostate, lung, and breast, it remains understudied compared with other DDR-involved molecules such as PARP and ATR. Here, we found that either gene knockout or drug intervention, ATM inhibition activated the cGAS/STING pathway and augmented MHC class I in CRC cells, and these effects could be amplified by radiation. Furthermore, we found that MHC class I upregulation induced by ATM inhibition is dependent on the activation of the NFκB/IRF1/NLRC5 pathway and independent of STING. Animal experiments have shown increasing infiltration and cytotoxic function of T cells and better survival in ATM-deficient tumors. This work indicated that ATM nonsense mutation predicted the clinical benefits of radiotherapy combined with immune checkpoint blockade for patients with CRC. It also provides a molecular mechanism rationale for ATM-targeted agents for patients with CRC.
Subject(s)
Ataxia Telangiectasia Mutated Proteins , Histocompatibility Antigens Class I , Immunotherapy , Membrane Proteins , Signal Transduction , Ataxia Telangiectasia Mutated Proteins/metabolism , Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors , Humans , Immunotherapy/methods , Animals , Membrane Proteins/metabolism , Membrane Proteins/genetics , Histocompatibility Antigens Class I/metabolism , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/immunology , Mice , Cell Line, Tumor , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Tumor Microenvironment , Colorectal Neoplasms/immunology , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Colorectal Neoplasms/therapy , Colorectal Neoplasms/metabolismABSTRACT
This study delves into the unexplored realm of castration-resistant prostate cancer (CRPC) by investigating the role of TRIM28 and its intricate molecular mechanisms using high-throughput single-cell transcriptome sequencing and advanced bioinformatics analysis. Our comprehensive examination unveiled dynamic TRIM28 expression changes, particularly in immune cells such as macrophages and CD8+ T cells within CRPC. Correlation analyses with TCGA data highlighted the connection between TRIM28 and immune checkpoint expression and emphasized its pivotal influence on the quantity and functionality of immune cells. Using TRIM28 knockout mouse models, we identified differentially expressed genes and enriched pathways, unraveling the potential regulatory involvement of TRIM28 in the cGAS-STING pathway. In vitro, experiments further illuminated that TRIM28 knockout in prostate cancer cells induced a notable anti-tumor immune effect by inhibiting M2 macrophage polarization and enhancing CD8+ T cell activity. This impactful discovery was validated in an in situ transplant tumor model, where TRIM28 knockout exhibited a deceleration in tumor growth, reduced proportions of M2 macrophages, and enhanced infiltration of CD8+ T cells. In summary, this study elucidates the hitherto unknown anti-tumor immune role of TRIM28 in CRPC and unravels its potential regulatory mechanism via the cGAS-STING signaling pathway. These findings provide novel insights into the immune landscape of CRPC, offering promising directions for developing innovative therapeutic strategies.
Subject(s)
CD8-Positive T-Lymphocytes , Membrane Proteins , Prostatic Neoplasms, Castration-Resistant , Tripartite Motif-Containing Protein 28 , Animals , Humans , Male , Mice , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Macrophages/metabolism , Macrophages/immunology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice, Inbred C57BL , Mice, Knockout , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Prostatic Neoplasms, Castration-Resistant/genetics , Prostatic Neoplasms, Castration-Resistant/metabolism , Prostatic Neoplasms, Castration-Resistant/immunology , Prostatic Neoplasms, Castration-Resistant/pathology , Signal Transduction , Tripartite Motif-Containing Protein 28/metabolism , Tripartite Motif-Containing Protein 28/geneticsABSTRACT
BACKGROUND: Cellular senescence features irreversible growth arrest and secretion of multiple proinflammatory cytokines. Cyclic GMP-AMP synthase (cGAS) detects DNA damage and activates the DNA-sensing pathway, resulting in the upregulation of inflammatory genes and induction of cellular senescence. This study aimed to investigate the effect of cGAS in regulating senescence of nucleus pulposus (NP) cells under inflammatory microenvironment. METHODS: The expression of cGAS was evaluated by immunohistochemical staining in rat intervertebral disc (IVD) degeneration model induced by annulus stabbing. NP cells were harvested from rat lumbar IVD and cultured with 10ng/ml IL-1ß for 48 h to induce premature senescence. cGAS was silenced by cGAS specific siRNA in NP cells and cultured with IL-1ß. Cellular senescence was evaluated by senescence-associated beta-galactosidase (SA-ß-gal) staining and flow cytometry. The expression of senescence-associated secretory phenotype including IL-6, IL-8, and TNF-a was evaluated by ELISA and western blotting. RESULTS: cGAS was detected in rat NP cells in cytoplasm and the expression was significantly increased in degenerated IVD. Culturing in 10ng/ml IL-1ß for 48 h induced cellular senescence in NP cells with attenuation of G1-S phase transition. In senescent NP cells the expression of cGAS, p53, p16, NF-kB, IL-6, IL-8, TNF-α was significantly increased while aggrecan and collagen type II was reduced than in normal NP cells. In NP cells with silenced cGAS, the expression of p53, p16, NF-kB, IL-6, IL-8, and TNF-α was reduced in inflammatory culturing with IL-1ß. CONCLUSION: cGAS was increased by NP cells in degenerated IVD promoting cellular senescence and senescent inflammatory phenotypes. Targeting cGAS may alleviate IVD degeneration by reducing NP cell senescence.
Subject(s)
Cellular Senescence , Intervertebral Disc Degeneration , Nucleotidyltransferases , Nucleus Pulposus , Rats, Sprague-Dawley , Cellular Senescence/physiology , Animals , Nucleus Pulposus/metabolism , Nucleus Pulposus/pathology , Intervertebral Disc Degeneration/pathology , Intervertebral Disc Degeneration/metabolism , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Cells, Cultured , Rats , Male , Inflammation/metabolism , Inflammation/pathology , Interleukin-1beta/metabolismABSTRACT
The mechanism regulating cellular senescence of postmitotic muscle cells is still unknown. cGAS-STING innate immune signaling was found to mediate cellular senescence in various types of cells, including postmitotic neuron cells, which however has not been explored in postmitotic muscle cells. Here by studying the myofibers from Zmpste24-/- progeria aged mice [an established mice model for Hutchinson-Gilford progeria syndrome (HGPS)], we observed senescence-associated phenotypes in Zmpste24-/- myofibers, which is coupled with increased oxidative damage to mitochondrial DNA (mtDNA) and secretion of senescence-associated secretory phenotype (SASP) factors. Also, Zmpste24-/- myofibers feature increased release of mtDNA from damaged mitochondria, mitophagy dysfunction, and activation of cGAS-STING. Meanwhile, increased mtDNA release in Zmpste24-/- myofibers appeared to be related with increased VDAC1 oligomerization. Further, the inhibition of VDAC1 oligomerization in Zmpste24-/- myofibers with VBIT4 reduced mtDNA release, cGAS-STING activation, and the expression of SASP factors. Our results reveal a novel mechanism of innate immune activation-associated cellular senescence in postmitotic muscle cells in aged muscle, which may help identify novel sets of diagnostic markers and therapeutic targets for progeria aging and aging-associated muscle diseases.
Subject(s)
Cellular Senescence , DNA, Mitochondrial , Membrane Proteins , Nucleotidyltransferases , Animals , Membrane Proteins/metabolism , Membrane Proteins/genetics , DNA, Mitochondrial/metabolism , DNA, Mitochondrial/genetics , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/genetics , Mice , Progeria/metabolism , Progeria/pathology , Progeria/genetics , Signal Transduction , Voltage-Dependent Anion Channel 1/metabolism , Voltage-Dependent Anion Channel 1/genetics , Mice, Knockout , Muscle Cells/metabolism , Mitophagy , Mitochondria/metabolism , Humans , Mice, Inbred C57BL , MetalloendopeptidasesABSTRACT
The Cyclic GMP-AMP synthase (cGAS) and cGAS/DncV-like nucleotidyltransferase (CD-NTase) enzymes belong to the key components of the innate immune sensor system that generates cyclic dinucleotide molecules in response to danger signals. Recently, it was discovered that CD-NTase in bacteria can undergo conjugation to protein substrates via an E1/E2 enzyme-mediated process, resembling ubiquitin modification system. Subsequently, these CD-NTase conjugated molecules will be hydrolyzed by the Cap3 enzyme in the same gene cluster. However, the experimental structure of bacterial CD-NTase recognized by Cap3 is unknown. Here, we first determined the crystal structure of the Cap3 enzyme in complex with the C-terminal tail of CD-NTase. Our structural and enzymatic analysis revealed that the C-terminal tail of CD-NTase is both necessary and sufficient for the Cap3-mediated hydrolysis of CD-NTase from its substrates. Interestingly, we further observed that after the hydrolysis reaction, the terminal glycine residue of the CD-NTase C-terminal tail was sequentially removed by Cap3, indicating that Cap3 might play a role in quenching the CD-NTase conjugation reaction. Our work provides experimental evidence elucidating the interaction between Cap3 and CD-NTase, and suggests a potential role for Cap3 in the bacterial Cyclic-oligonucleotide-based anti-phage signaling system (CBASS).
Subject(s)
Nucleotidyltransferases , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/chemistry , Nucleotidyltransferases/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Crystallography, X-Ray , Models, Molecular , Protein Conformation , HydrolysisABSTRACT
Nucleotide sugars (UDP-Sugars) are essential for the production of polysaccharides and glycoconjugates utilized in medicines, cosmetics, and food industries. The enzyme Galactose-1-phosphate uridylyltransferase (GalU; EC 2.7.7.12) is responsible for the synthesis of UDP-galactose from α-d-galactose-1-phosphate (Gal-1P) and UTP. A novel bacterial GalU (TiGalU) encoded from a thermophilic bacterium, Thermodesulfatator indicus, was successfully purified using the Ni-NTA column after being expressed in Escherichia coli. The optimal pH for recombinant TiGalU was determined to be 5.5. The optimum temperature of the enzyme was 45 °C. The activity of TiGalU was not dependent on Mg2+ and was strongly inhibited by SDS. When coupled with galactose kinase (GALK1) and ß-1,4-galactosyltransferase 1 (B4GALT1), the enzyme enabled the one-pot synthesis of Gal-ß-1,4-GlcNAc-X by utilizing galactose and UTP as substrates. This study reported the in vitro biosynthesis of Gal-ß-1,4-GlcNAc-X for the first time, providing an environmentally friendly way to biosynthesis glycosides and other polysaccharides.
Subject(s)
Escherichia coli , Recombinant Proteins , Escherichia coli/genetics , Escherichia coli/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/biosynthesis , Recombinant Proteins/isolation & purification , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Bacterial Proteins/biosynthesis , Bacterial Proteins/isolation & purification , UTP-Hexose-1-Phosphate Uridylyltransferase/genetics , UTP-Hexose-1-Phosphate Uridylyltransferase/metabolism , UTP-Hexose-1-Phosphate Uridylyltransferase/chemistry , Gene Expression , Nucleotidyltransferases/genetics , Nucleotidyltransferases/metabolism , Nucleotidyltransferases/chemistry , Cloning, Molecular , Galactosephosphates/metabolism , Galactosephosphates/genetics , Galactosyltransferases/genetics , Galactosyltransferases/metabolism , Galactosyltransferases/chemistryABSTRACT
The eye is one of the most vulnerable parts of the human body. There are many kinds of ophthalmic diseases, which are caused by multiple factors. Generally, ophthalmic diseases have the characteristics of complicated etiology and difficult therapy. With the development of the times, ophthalmic diseases have become a major problem that affects people's lives. Inflammation, a major factor inducing ocular diseases, is one of the most popular research directions. The cGAS/STING pathway is a recently discovered inflammatory signaling pathway, which recognizes double-stranded DNA (dsDNA) as an activation signal to promote the expression of downstream cytokines that promote inflammatory response or autoimmune response. Since most of the current treatments for ophthalmic diseases mainly rely on surgery, it is of positive significance to explore the pathogenesis for the discovery of drug targets. This review summarize the research progress of the cGAS/STING pathway in major ophthalmic diseases by introducing the correlation between classical inflammatory pathway and ophthalmic diseases, in order to predict the research direction and methods targeting the cGAS/STING pathway in the pathogenesis of ophthalmic diseases, and also provide guidance for the mechanism as well as molecular targets of ophthalmic diseases.
Subject(s)
Eye Diseases , Membrane Proteins , Nucleotidyltransferases , Signal Transduction , Humans , Nucleotidyltransferases/metabolism , Membrane Proteins/metabolism , Animals , Eye Diseases/metabolism , Inflammation/metabolismABSTRACT
Purpose: The cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) stimulator of interferon gene (STING) pathway is a crucial cascade in the inflammatory response initiated by the recognition of cytosolic double-stranded DNA (dsDNA). The aim of this study was to evaluate the effect of STING inhibitor in murine choroidal neovascularization (CNV). Methods: To investigate whether the cGAS-STING pathway is activated during CNV, CNV was induced using laser photocoagulation in male C57BL/6J mice. The expression of change of cGAS and STING during CNV development was confirmed by Western-blotting. H-151, a potent STING palmitoylation antagonist, was used as a STING inhibitor. H-151 was administered intravitreally immediately after laser induction. To confirm the role of the cGAS-STING pathway in CNV formation, we evaluated CNV size and performed fundus fluorescein angiography. Results: The expression levels of cGAS and STING were significantly upregulated in the RPE-choroid complex after CNV induction, and dsDNA merged with cGAS was observed in CNV lesions. Intravitreal administration of H-151 suppressed CNV development and fluorescent leakage from neovessels. In CNV lesions, the high expression of STING and cGAS was observed in infiltrating F4/80+ macrophages. H-151 administration attenuated downstream signals of the cGAS-STING pathway, including the phosphorylation of nuclear factor-κB, and downregulated the expression of interleukin 1ß. Conclusions: These findings support that the inhibition of cGAS-STING pathway treats abnormal ocular angiogenesis.