RESUMEN

Beyond its role as the bearer of genetic material, DNA also plays a crucial role in the activation phase of innate immunity. Pathogen recognition receptors (PRRs) and their homologs, pathogen-associated molecular patterns (PAMPs), form the foundation for driving innate immune activation and the induction of immune responses during infection. In the context of DNA viruses or bacterial infections, specific DNA sequences are recognized and bound by DNA sensors, marking the DNA as a PAMP for host recognition and subsequent activation of innate immunity. The primary DNA sensor pathway known to date is cGAS-STING, which can induce Type I interferons (IFN) and innate immune responses against viruses and bacteria. Additionally, the cGAS-STING pathway has been identified to mediate functions in autophagy and senescence. Herein, we introduce methods for using DNA PAMPs as molecular tools to study the role of cGAS-STING and its signaling pathway in regulating innate immunity, both in vitro and in vivo.

Asunto(s)

ADN , Inmunidad Innata , Proteínas de la Membrana , Nucleotidiltransferasas , Transducción de Señal , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Humanos , ADN/metabolismo , ADN/genética , Animales , Moléculas de Patrón Molecular Asociado a Patógenos/metabolismo , Moléculas de Patrón Molecular Asociado a Patógenos/inmunología , Ratones

RESUMEN

With the rapid development of CRISPR-Cas9 technology, gene editing has become a powerful tool for studying gene function. Specifically, in the study of the mechanisms by which natural immune responses combat viral infections, gene knockout mouse models have provided an indispensable platform. This article describes a detailed protocol for constructing gene knockout mice using the CRISPR-Cas9 system. This field focuses on the design of single-guide RNAs (sgRNAs) targeting the antiviral immune gene cGAS, embryo microinjection, and screening and verification of gene editing outcomes. Furthermore, this study provides methods for using cGAS gene knockout mice to analyze the role of specific genes in natural immune responses. Through this protocol, researchers can efficiently generate specific gene knockout mouse models, which not only helps in understanding the functions of the immune system but also offers a powerful experimental tool for exploring the mechanisms of antiviral innate immunity.

Asunto(s)

Sistemas CRISPR-Cas , Edición Génica , Inmunidad Innata , Ratones Noqueados , ARN Guía de Sistemas CRISPR-Cas , Animales , Inmunidad Innata/genética , Ratones , ARN Guía de Sistemas CRISPR-Cas/genética , Edición Génica/métodos , Técnicas de Inactivación de Genes/métodos , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Virosis/inmunología , Virosis/genética

RESUMEN

Detection of cytosolic DNA by the cyclic GMP-AMP (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway provides immune defense against pathogens and cancer but can also cause autoimmunity when overactivated. The exonuclease three prime repair exonuclease 1 (TREX1) degrades DNA in the cytosol and prevents cGAS activation by self-DNA. Loss-of-function mutations of the TREX1 gene are linked to autoimmune diseases such as Aicardi-Goutières syndrome, and mice deficient in TREX1 develop lethal inflammation in a cGAS-dependent manner. In order to determine the type of cells in which cGAS activation drives autoinflammation, we generated conditional cGAS knockout mice on the Trex1-/- background. Here, we show that genetic ablation of the cGAS gene in classical dendritic cells (cDCs), but not in macrophages, was sufficient to rescue Trex1-/- mice from all observed disease phenotypes including lethality, T cell activation, tissue inflammation, and production of antinuclear antibodies and interferon-stimulated genes. These results show that cGAS activation in cDC causes autoinflammation in response to self-DNA accumulated in the absence of TREX1.

Asunto(s)

Autoinmunidad , Células Dendríticas , Exodesoxirribonucleasas , Ratones Noqueados , Nucleotidiltransferasas , Fosfoproteínas , Animales , Exodesoxirribonucleasas/genética , Exodesoxirribonucleasas/deficiencia , Exodesoxirribonucleasas/metabolismo , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/deficiencia , Células Dendríticas/inmunología , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosfoproteínas/inmunología , Ratones , Autoinmunidad/inmunología , Malformaciones del Sistema Nervioso/genética , Malformaciones del Sistema Nervioso/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/genética , Enfermedades Autoinmunes del Sistema Nervioso/patología , Inflamación/inmunología , Inflamación/genética , Macrófagos/inmunología , Macrófagos/metabolismo , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/genética

RESUMEN

Nucleotidyltransferases (NTases) control diverse physiological processes, including RNA modification, DNA replication and repair, and antibiotic resistance. The Mycobacterium tuberculosis NTase toxin family, MenT, modifies tRNAs to block translation. MenT toxin activity can be stringently regulated by diverse MenA antitoxins. There has been no unifying mechanism linking antitoxicity across MenT homologues. Here we demonstrate through structural, biochemical, biophysical and computational studies that despite lacking kinase motifs, antitoxin MenA1 induces auto-phosphorylation of MenT1 by repositioning the MenT1 phosphoacceptor T39 active site residue towards bound nucleotide. Finally, we expand this predictive model to explain how unrelated antitoxin MenA3 is similarly able to induce auto-phosphorylation of cognate toxin MenT3. Our study reveals a conserved mechanism for the control of tuberculosis toxins, and demonstrates how active site auto-phosphorylation can regulate the activity of widespread NTases.

Asunto(s)

Dominio Catalítico , Mycobacterium tuberculosis , Nucleotidiltransferasas , Fosforilación , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/química , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/química , Modelos Moleculares , ARN de Transferencia/metabolismo , ARN de Transferencia/genética , Cristalografía por Rayos X

RESUMEN

Mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) gastric cancer (GC) exhibits an immune-active tumor microenvironment (TME) compared to MMR proficient (pMMR)/microsatellite stable/Epstein-Barr virus-negative [EBV (-)] GC. The tumor cell-intrinsic cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has been considered a key regulator of immune cell activation in the TME. However, its significance in regulating the immune-active TME in dMMR/MSI-H GC remains unclear. Here, we demonstrated that tumor cell-intrinsic cGAS-STING was highly expressed in dMMR GC compared to pMMR/EBV (-) GC. The expression of tumor cell-intrinsic STING was significantly and positively associated with the number of CD8+ tumor-infiltrating lymphocytes in GC. Analysis of TCGA datasets revealed that the expression of interferon-stimulated genes and STING downstream T-cell attracting chemokines was significantly higher in MSI-H GC compared to other subtypes of GC with EBV (-). These results suggest that tumor cell-intrinsic STING signaling plays a key role in activating immune cells in the dMMR/MSI-H GC TME and might serve as a novel biomarker predicting the efficacy of immunotherapy for GC treatment.

Asunto(s)

Linfocitos T CD8-positivos , Linfocitos Infiltrantes de Tumor , Proteínas de la Membrana , Inestabilidad de Microsatélites , Transducción de Señal , Neoplasias Gástricas , Microambiente Tumoral , Neoplasias Gástricas/genética , Neoplasias Gástricas/inmunología , Neoplasias Gástricas/patología , Neoplasias Gástricas/metabolismo , Humanos , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Microambiente Tumoral/inmunología , Masculino , Femenino , Reparación de la Incompatibilidad de ADN/genética , Persona de Mediana Edad , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Regulación Neoplásica de la Expresión Génica , Anciano

RESUMEN

Immune checkpoint blockade (ICB) has emerged as a promising therapeutic option for hepatocellular carcinoma (HCC), but resistance to ICB occurs and patient responses vary. Here, we uncover protein arginine methyltransferase 3 (PRMT3) as a driver for immunotherapy resistance in HCC. We show that PRMT3 expression is induced by ICB-activated T cells via an interferon-gamma (IFNγ)-STAT1 signaling pathway, and higher PRMT3 expression levels correlate with reduced numbers of tumor-infiltrating CD8+ T cells and poorer response to ICB. Genetic depletion or pharmacological inhibition of PRMT3 elicits an influx of T cells into tumors and reduces tumor size in HCC mouse models. Mechanistically, PRMT3 methylates HSP60 at R446 to induce HSP60 oligomerization and maintain mitochondrial homeostasis. Targeting PRMT3-dependent HSP60 methylation disrupts mitochondrial integrity and increases mitochondrial DNA (mtDNA) leakage, which results in cGAS/STING-mediated anti-tumor immunity. Lastly, blocking PRMT3 functions synergize with PD-1 blockade in HCC mouse models. Our study thus identifies PRMT3 as a potential biomarker and therapeutic target to overcome immunotherapy resistance in HCC.

Asunto(s)

Carcinoma Hepatocelular , Chaperonina 60 , Neoplasias Hepáticas , Proteínas de la Membrana , Nucleotidiltransferasas , Proteína-Arginina N-Metiltransferasas , Transducción de Señal , Animales , Proteína-Arginina N-Metiltransferasas/metabolismo , Proteína-Arginina N-Metiltransferasas/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Humanos , Ratones , Carcinoma Hepatocelular/inmunología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/inmunología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Chaperonina 60/metabolismo , Chaperonina 60/genética , Línea Celular Tumoral , Metilación , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Mitocondrias/metabolismo , Ratones Endogámicos C57BL , ADN Mitocondrial/genética , ADN Mitocondrial/inmunología , ADN Mitocondrial/metabolismo , Interferón gamma/metabolismo , Interferón gamma/inmunología , Masculino

RESUMEN

During homeostasis, the endoplasmic reticulum (ER) maintains productive transmembrane and secretory protein folding that is vital for proper cellular function. The ER-resident HSP70 chaperone, binding immunoglobulin protein (BiP), plays a pivotal role in sensing ER stress to activate the unfolded protein response (UPR). BiP function is regulated by the bifunctional enzyme filamentation induced by cyclic-AMP domain protein (FicD) that mediates AMPylation and deAMPylation of BiP in response to changes in ER stress. AMPylated BiP acts as a molecular rheostat to regulate UPR signaling, yet little is known about the molecular consequences of FicD loss. In this study, we investigate the role of FicD in mouse embryonic fibroblast (MEF) response to pharmacologically and metabolically induced ER stress. We find differential BiP AMPylation signatures when comparing robust chemical ER stress inducers to physiological glucose starvation stress and recovery. Wildtype MEFs respond to pharmacological ER stress by down-regulating BiP AMPylation. Conversely, BiP AMPylation in wildtype MEFs increases upon metabolic stress induced by glucose starvation. Deletion of FicD results in widespread gene expression changes under baseline growth conditions. In addition, FicD null MEFs exhibit dampened UPR signaling, altered cell stress recovery response, and unconstrained protein secretion. Taken together, our findings indicate that FicD is important for tampering UPR signaling, stress recovery, and the maintenance of secretory protein homeostasis.

Asunto(s)

Chaperón BiP del Retículo Endoplásmico , Estrés del Retículo Endoplásmico , Fibroblastos , Glucosa , Respuesta de Proteína Desplegada , Animales , Ratones , Embrión de Mamíferos/metabolismo , Embrión de Mamíferos/citología , Retículo Endoplásmico/metabolismo , Chaperón BiP del Retículo Endoplásmico/metabolismo , Fibroblastos/metabolismo , Glucosa/metabolismo , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico/genética , Ratones Noqueados , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Transducción de Señal

RESUMEN

BACKGROUND: This study aimed to investigate the differential expression levels of the cGAS-STING pathway in peripheral blood mononuclear cells (PBMCs) of spinal tuberculosis (TB) patients with different progression and its feasibility as a diagnostic marker. METHODS: Peripheral blood and medical records of 25 patients with spinal TB and 10 healthy individuals, were prospectively collected and analyzed. PBMCs and serum were extracted from peripheral blood and the expression levels of the cGAS-STING pathway in PBMCs were measured by real-time PCR (RT-PCR) and serum interferon ß (IFN-ß) expression levels were measured by enzyme-linked immunosorbent assay (ELISA). The expression of Interferon regulatory Factor 3 (IRF3) in PBMCs was measured using western blot. Statistical analysis was performed using the SPSS 26.0 statistical package. RESULTS: The results showed that the expression level of the TANK-binding kinase 1 (TBK1) and IRF3 was significantly higher in PBMCs (P < 0.05), in patients with active lesions than in patients with stable lesions. The serum concentration of IFN-ß was significantly higher in patients with active lesions (P = 0.028). Compared with healthy individuals, the expression level of the cGAS-STING pathway was elevated in PBMCs of TB patients (P < 0.05), and the difference in the expression level of IFN-ß was not statistically significant (P > 0.05), and the serum IFN-ß concentration was elevated (P < 0.05). The calculated AUC values for TBK1 and IRF3 in PBMCs, IFN-ß in serum and erythrocyte sedimentation rate (ESR) to distinguish between patients with active and stable lesions were 0.732, 0.714, 0.839, and 0.714 respectively. CONCLUSIONS: The expression level of TBK1 and IRF3 in PBMCs, and IFN-ß in the serum of patients with spinal TB is positively correlated with disease activity. TBK1 has higher specificity and IFN-ß in serum has higher sensitivity when used to differentiate between patients with active and stable lesions.

Asunto(s)

Factor 3 Regulador del Interferón , Leucocitos Mononucleares , Proteínas de la Membrana , Nucleotidiltransferasas , Tuberculosis de la Columna Vertebral , Humanos , Leucocitos Mononucleares/metabolismo , Masculino , Femenino , Adulto , Proteínas de la Membrana/sangre , Proteínas de la Membrana/genética , Persona de Mediana Edad , Nucleotidiltransferasas/genética , Factor 3 Regulador del Interferón/genética , Factor 3 Regulador del Interferón/metabolismo , Factor 3 Regulador del Interferón/sangre , Tuberculosis de la Columna Vertebral/sangre , Tuberculosis de la Columna Vertebral/genética , Interferón beta/sangre , Transducción de Señal , Proteínas Serina-Treonina Quinasas/genética , Biomarcadores/sangre , Estudios Prospectivos , Adulto Joven , Anciano

RESUMEN

DNA damage is typically caused during cell growth by DNA replication stress or exposure to endogenous or external toxins. The accumulation of damaged DNA causes genomic instability, which is the root cause of many serious disorders. Multiple cellular organisms utilize sophisticated signaling pathways against DNA damage, collectively known as DNA damage response (DDR) networks. Innate immune responses are activated following cellular abnormalities, including DNA damage. Interestingly, recent studies have indicated that there is an intimate relationship between the DDR network and innate immune responses. Diverse kinds of cytosolic DNA sensors, such as cGAS and STING, recognize damaged DNA and induce signals related to innate immune responses, which link defective DDR to innate immunity. Moreover, DDR components operate in immune signaling pathways to induce IFNs and/or a cascade of inflammatory cytokines via direct interactions with innate immune modulators. Consistently, defective DDR factors exacerbate the innate immune imbalance, resulting in severe diseases, including autoimmune disorders and tumorigenesis. Here, the latest progress in understanding crosstalk between the DDR network and innate immune responses is reviewed. Notably, the dual function of innate immune modulators in the DDR network may provide novel insights into understanding and developing targeted immunotherapies for DNA damage-related diseases, even carcinomas.

Asunto(s)

Daño del ADN , Inmunidad Innata , Humanos , Animales , Transducción de Señal , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Neoplasias/inmunología , Enfermedades Autoinmunes/inmunología , Proteínas de la Membrana

RESUMEN

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.

Asunto(s)

Heptosas , Nucleotidiltransferasas , Moléculas de Patrón Molecular Asociado a Patógenos , Animales , Humanos , Ratones , Secuencias de Aminoácidos , Archaea/enzimología , Bacterias/enzimología , Bacterias/metabolismo , Heptosas/biosíntesis , Heptosas/inmunología , Inmunidad Innata , Nucleotidiltransferasas/química , Nucleotidiltransferasas/clasificación , Nucleotidiltransferasas/genética , Moléculas de Patrón Molecular Asociado a Patógenos/inmunología , Moléculas de Patrón Molecular Asociado a Patógenos/metabolismo , Proteínas Quinasas/metabolismo , Virus/enzimología

RESUMEN

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.

Asunto(s)

Autofagia , Daño del ADN , ADN Helicasas , Inflamación , Enzimas Multifuncionales , Nucleotidiltransferasas , Estructuras R-Loop , ARN Helicasas , Humanos , Autofagia/genética , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/deficiencia , ADN Helicasas/metabolismo , ADN Helicasas/genética , ADN Helicasas/deficiencia , Enzimas Reparadoras del ADN/metabolismo , Enzimas Reparadoras del ADN/genética , Enzimas Reparadoras del ADN/deficiencia , Exodesoxirribonucleasas/metabolismo , Exodesoxirribonucleasas/genética , Inmunidad Innata , Inflamación/patología , Inflamación/metabolismo , Inflamación/genética , Enzimas Multifuncionales/metabolismo , Enzimas Multifuncionales/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Fosfoproteínas , ARN Helicasas/metabolismo , ARN Helicasas/genética

RESUMEN

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.

Asunto(s)

Proteínas de la Membrana , Nucleotidiltransferasas , Neoplasias Ováricas , Neoplasias Pancreáticas , Proteína 1 de Unión al Supresor Tumoral P53 , Proteína 1 de Unión al Supresor Tumoral P53/metabolismo , Proteína 1 de Unión al Supresor Tumoral P53/genética , Femenino , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Humanos , Animales , Neoplasias Ováricas/inmunología , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Neoplasias Ováricas/metabolismo , Neoplasias Pancreáticas/inmunología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/metabolismo , Ratones , Línea Celular Tumoral , Roturas del ADN de Doble Cadena , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Transducción de Señal , Linfocitos T CD8-positivos/inmunología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéutico , Ratones Endogámicos C57BL , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Ratones Noqueados , Carcinoma Ductal Pancreático/inmunología , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Inmunidad Innata

RESUMEN

Mitochondrial DNA (mtDNA) is frequently released from mitochondria, activating cGAS-STING signaling and inducing type I IFNs (IFN-Is) in systemic lupus erythematosus (SLE). Meanwhile, whether and how the glycolytic pathway was involved in such IFN-I responses in human SLE remain unclear. In this study, we found that monocytes from SLE patients exerted robust IFN-I generation and elevated level of cytosolic mtDNA. Transfection of mtDNA into THP-1 macrophages was efficient in inducing IFN-I responses, together with the strong glycolytic pathway that promoted lactate production, mimicking the SLE phenotype. Blockade of lactate generation abrogated such IFN-I responses and, vice versa, exogenous lactate enhanced the IFN-I generation. Mechanistically, lactate promoted the lactylation of cGAS, which inhibited its binding to E3 ubiquitination ligase MARCHF5, blocking cGAS degradation and leading to strong IFN-I responses. In accordance, targeting lactate generation alleviated disease development in humanized SLE chimeras. Collectively, cytosolic mtDNA drives metabolic adaption toward the glycolytic pathway, promoting lactylation of cGAS for licensing IFN-I responses in human SLE and thereby assigning the glycolytic pathway as a promising therapeutic target for SLE.

Asunto(s)

ADN Mitocondrial , Lupus Eritematoso Sistémico , Nucleotidiltransferasas , Humanos , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , ADN Mitocondrial/inmunología , ADN Mitocondrial/genética , Interferón Tipo I/metabolismo , Interferón Tipo I/inmunología , Femenino , Glucólisis , Animales , Ratones , Transducción de Señal/inmunología , Mitocondrias/metabolismo , Mitocondrias/inmunología , Masculino , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ácido Láctico/metabolismo , Monocitos/inmunología , Monocitos/metabolismo , Células THP-1 , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Adulto

RESUMEN

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.

Asunto(s)

Linfocitos T CD8-positivos , Células Endoteliales , Nucleotidiltransferasas , Estructuras Linfoides Terciarias , Animales , Nucleotidiltransferasas/inmunología , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Ratones , Células Endoteliales/inmunología , Estructuras Linfoides Terciarias/inmunología , Linfocitos T CD8-positivos/inmunología , Quimiocina CCL5/inmunología , Quimiocina CCL5/genética , Ratones Endogámicos C57BL , Ratones Transgénicos , Transducción de Señal/inmunología , Receptores CCR5/inmunología , Receptores CCR5/genética , Receptores CCR5/metabolismo , Autoinmunidad/inmunología

RESUMEN

Characterized by progressive degeneration of retinal ganglion cells (RGCs) and vision loss, glaucoma is the primary cause of irreversible blindness, incurable and affecting over 78 million patients. However, pathogenic mechanisms leading to glaucoma-induced RGC loss are incompletely understood. Unexpectedly, we found that cGAS-STING (2'3'-cyclic GMP-AMP-stimulator of interferon genes) signaling, which surveils displaced double-stranded DNA (dsDNA) in the cytosol and initiates innate immune responses, was robustly activated during glaucoma in retinal microglia in distinct murine models. Global or microglial deletion of STING markedly relieved glaucoma symptoms and protected RGC degeneration and vision loss, while mice bearing genetic cGAS-STING supersensitivity aggravated retinal neuroinflammation and RGC loss. Mechanistically, dsDNA from tissue injury activated microglial cGAS-STING signaling, causing deleterious macroglia reactivity in retinas by cytokine-mediated microglia-macroglia interactions, progressively driving apoptotic death of RGCs. Remarkably, preclinical investigations of targeting cGAS-STING signaling by intraocular injection of TBK1i or anti-IFNAR1 antibody prevented glaucoma-induced losses of RGCs and vision. Therefore, we unravel an essential role of cGAS-STING signaling underlying glaucoma pathogenesis and suggest promising therapeutic strategies for treating this devastating disease.

Asunto(s)

Glaucoma , Proteínas de la Membrana , Microglía , Nucleotidiltransferasas , Transducción de Señal , Animales , Ratones , Modelos Animales de Enfermedad , Glaucoma/patología , Glaucoma/metabolismo , Glaucoma/inmunología , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Microglía/metabolismo , Microglía/patología , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Células Ganglionares de la Retina/patología , Células Ganglionares de la Retina/metabolismo

RESUMEN

Disrupting mitochondrial function in malignant cells is a promising strategy to enhance anticancer immunity. We have recently demonstrated that depriving colorectal cancer cells of serine results in mitochondrial dysfunction coupled with the cytosolic accumulation of mitochondrial DNA and consequent activation of CGAS- and STING-dependent tumor-targeting immune responses.

Asunto(s)

ADN Mitocondrial , Mitocondrias , Animales , Humanos , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/patología , ADN Mitocondrial/metabolismo , ADN Mitocondrial/genética , Proteínas de la Membrana/genética , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Mitocondrias/metabolismo , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/inmunología , Nucleotidiltransferasas/metabolismo

RESUMEN

DNA damage has been implicated in the stimulation of the type 1 interferon (T1IFN) response. Here, we show that downregulation of the DNA repair protein, polynucleotide kinase/phosphatase (PNKP), in a variety of cell lines causes robust phosphorylation of STAT1, upregulation of interferon-stimulated genes and persistent accumulation of cytosolic DNA, all of which are indicators for the activation of the T1IFN response. Furthermore, this did not require damage induction by ionizing radiation. Instead, our data revealed that production of reactive oxygen species (ROS) synergises with PNKP loss to potentiate the T1IFN response, and that loss of PNKP significantly compromises mitochondrial DNA (mtDNA) integrity. Depletion of mtDNA or treatment of PNKP-depleted cells with ROS scavengers abrogated the T1IFN response, implicating mtDNA as a significant source of the cytosolic DNA required to potentiate the T1IFN response. The STING signalling pathway is responsible for the observed increase in the pro-inflammatory gene signature in PNKP-depleted cells. While the response was dependent on ZBP1, cGAS only contributed to the response in some cell lines. Our data have implications for cancer therapy, since PNKP inhibitors would have the potential to stimulate the immune response, and also to the neurological disorders associated with PNKP mutation.

Asunto(s)

Enzimas Reparadoras del ADN , ADN Mitocondrial , Interferón Tipo I , Fosfotransferasas (Aceptor de Grupo Alcohol) , Radiación Ionizante , Especies Reactivas de Oxígeno , Humanos , Interferón Tipo I/metabolismo , Interferón Tipo I/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Enzimas Reparadoras del ADN/metabolismo , Enzimas Reparadoras del ADN/genética , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Reparación del ADN , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT1/genética , Daño del ADN , Línea Celular , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Transducción de Señal , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Fosforilación , Citosol/metabolismo , Línea Celular Tumoral , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética

RESUMEN

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.

Asunto(s)

Inhibidores de Puntos de Control Inmunológico , Proteínas de la Membrana , Miocarditis , Nucleotidiltransferasas , Piroptosis , Animales , Miocarditis/inmunología , Miocarditis/patología , Miocarditis/inducido químicamente , Miocarditis/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Ratones , Masculino , Humanos , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Transducción de Señal , Ratones Endogámicos C57BL , Ratones Noqueados , ADN Mitocondrial/metabolismo , ADN Mitocondrial/genética , Femenino , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Miocitos Cardíacos/efectos de los fármacos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas de Unión a Fosfato/metabolismo , Proteínas de Unión a Fosfato/genética , Gasderminas

RESUMEN

The cGAS/STING pathway is a crucial immune activator in cancer biology, triggering innate immunosurveillance against tumors by sensing and reacting to endogenous mitochondrial DNA (mtDNA). In this issue of Cancer Research, research by Saha and colleagues highlights the significant impact of serine deprivation on this pathway, thereby unveiling its potential for anticancer therapy. Serine is essential for cellular metabolism and influences tumor growth and immune responses. Depriving cells of serine caused mitochondrial dysfunction and the release of mtDNA into the cytosol, activating the cGAS/STING pathway and inducing type I IFN responses. In mouse models, serine deprivation enhanced antitumor immunity, with increased tumoral immune infiltration, including CD4+/CD8+ T cells and type I IFN responses. Clinically, a genetic signature indicative of lower serine enrichment in colorectal cancer patients correlated with immune activation and improved survival. Furthermore, combining serine deprivation with PD1 blockade significantly reduced tumor volume and led to long-term immunity in mice, suggesting that serine depletion enhances the efficacy of immune checkpoint blockade. These findings propose serine deprivation as a promising strategy to boost antitumor immunity and improve cancer patient outcomes. See related article by Saha et al., p. 2645.

Asunto(s)

Proteínas de la Membrana , Neoplasias , Nucleotidiltransferasas , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Humanos , Animales , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Ratones , Neoplasias/inmunología , Neoplasias/patología , Neoplasias/metabolismo , Neoplasias/genética , ADN Mitocondrial/genética , ADN Mitocondrial/inmunología , Transducción de Señal/inmunología , Serina/metabolismo

RESUMEN

Recently, various cancer types have been identified to express a distinct subset of Interferon-stimulated genes (ISGs) that mediate therapy resistance. The mechanism through which cancer cells maintain prolonged Interferon stimulation effects to coordinate resistance remains unclear. Our research demonstrated that aberrant upregulation of TAGLN2 is associated with gastric cancer progression, and inhibiting its expression renders gastric cancer cells more susceptible to chemotherapy and radiation. We uncovered a novel role for TAGLN2 in the upregulation of resistance signature ISGs by enhancing YBX1-associated ssDNA aggregation and cGAS-STING pathway activation. TAGLN2 modulates YBX1 by recruiting c-Myc and SOX9 to YBX1 promoter region and directly interacting with AKT-YBX1, thereby enhancing YBX1 phosphorylation and nuclear translocation. Significantly, targeted downregulation of key proteins, inhibition of the TAGLN2-YBX1-AKT interaction (using Fisetin or MK2206) or disruption of the cGAS-STING pathway substantially reduced ssDNA accumulation, subsequent ISGs upregulation, and therapy resistance. The combination of Cisplatin with MK2206 displayed a synergistic effect in the higher TAGLN2-expressing xenograft tumors. Clinical analysis indicated that a derived nine-gene set effectively predicts therapeutic sensitivity and long-term prognosis in gastric cancer patients. These findings suggest that TAGLN2, YBX1 and induced ISGs are novel predictive markers for clinical outcomes, and targeting this axis is an attractive therapeutic sensitization strategy.

Asunto(s)

Daño del ADN , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Neoplasias Gástricas , Proteína 1 de Unión a la Caja Y , Humanos , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/tratamiento farmacológico , Proteína 1 de Unión a la Caja Y/metabolismo , Proteína 1 de Unión a la Caja Y/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Animales , Línea Celular Tumoral , Ratones , Resistencia a Antineoplásicos/genética , Compuestos Heterocíclicos con 3 Anillos/farmacología , Ratones Desnudos , Interferones/metabolismo , Regulación Neoplásica de la Expresión Génica , Cisplatino/farmacología , Cisplatino/uso terapéutico , Proteínas de Microfilamentos/metabolismo , Proteínas de Microfilamentos/genética , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Femenino , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Ratones Endogámicos BALB C , Masculino