Regulation and function of the cGAS-STING pathway of cytosolic DNA sensing. Nat Immunol. 2016;17:1142-1149. [PMID: 27648547 DOI: 10.1038/ni.3558]

The role of cisplatin in modulating the tumor immune microenvironment and its combination therapy strategies: a new approach to enhance anti-tumor efficacy

Cisplatin is a platinum-based drug that is frequently used to treat multiple tumors. The anti-tumor effect of cisplatin is closely related to the tumor immune microenvironment (TIME), which includes several immune cell types, such as the tumor-associated macrophages (TAMs), cytotoxic T-lymphocytes (CTLs), dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and natural killer (NK) cells. The interaction between these immune cells can promote tumor survival and chemoresistance, and decrease the efficacy of cisplatin monotherapy. Therefore, various combination treatment strategies have been devised to enhance patient responsiveness to cisplatin therapy. Cisplatin can augment anti-tumor immune responses in combination with immune checkpoint blockers (such as PD-1/PD-L1 or CTLA4 inhibitors), lipid metabolism disruptors (like FASN inhibitors and SCD inhibitors) and nanoparticles (NPs), resulting in better outcomes. Exploring the interaction between cisplatin and the TIME will help identify potential therapeutic targets for improving the treatment outcomes in cancer patients.

Manganese-coordinated nanoparticles loaded with CHK1 inhibitor dually activate cGAS-STING pathway and enhance efficacy of immune checkpoint therapy

Notable advancements have been made in utilizing immune checkpoint blockade (ICB) for the treatment of various cancers. However, the overall response rates and therapeutic effectiveness remain unsatisfactory. One cause is the inadequate immune environment characterized by poor T cell infiltration in tumors. To address these limitations, enhancing immune infiltration is crucial for optimizing the therapeutic efficacy of ICB. Activating the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is essential for initiating immune response and has become a potential target for developing combination therapies with ICB. In this study, we designed and fabricated manganese-containing nanoparticles loaded with the CHK1 inhibitor PF477736, which were subsequently encapsulated with macrophage membrane (PF/MMSN@MPM). This innovative design achieved excellent tumor targeting and demonstrated potent antitumor effects. The combination therapy dually amplified the cGAS-STING pathway, causing a cascade of enhanced therapeutic effects against tumors. Furthermore, single-cell mass cytometry (CyTOF) analysis revealed that PF/MMSN@MPM enhanced the activation and infiltration of immune cells. Moreover, the combination of PF/MMSN@MPM with anti-PD-1 (αPD-1) exhibited a stronger therapeutic effect compared to αPD-1 alone. PF/MMSN@MPM precisely and synergistically activated the cGAS-STING pathway, significantly improving therapeutic efficacy of ICB, and offering promising potential for tumor therapy.

Glioblastoma cells secrete ICAM1 via FASN signaling to promote glioma-associated macrophage infiltration

Glioma-associated macrophages (GAMs) constitute the most abundant subset of immune cells in the glioblastoma (GBM) microenvironment, but the underlying mechanism of intense infiltration needs to be elucidated. In this study, we found that GBM cells secrete ICAM1 via FASN signaling to promote GAM infiltration. FASN expression is correlated with GAM density in GBM patients. In vitro experiments revealed that FASN regulates the type-I interferon pathway, particularly STAT1 expression. Moreover, disrupting FASN-STAT1 signaling through the overexpression or inhibition of FASN or STAT1 in GBM cells strongly influences microglial recruitment. Additionally, ICAM1 acts as a direct transcriptional candidate of FASN-STAT1 and a paracrine soluble factor, recruiting microglia to GBM tumors. This study revealed crosstalk between GBM cells and GAMs through FASN-STAT1-ICAM1 signaling to promote microglial infiltration, suggesting potential strategies for treating GBM patients.

The cGAS-STING-interferon regulatory factor 7 pathway regulates neuroinflammation in Parkinson's disease

JOURNAL/nrgr/04.03/01300535-202508000-00026/figure1/v/2024-09-30T120553Z/r/image-tiff Interferon regulatory factor 7 plays a crucial role in the innate immune response. However, whether interferon regulatory factor 7-mediated signaling contributes to Parkinson's disease remains unknown. Here we report that interferon regulatory factor 7 is markedly up-regulated in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease and co-localizes with microglial cells. Both the selective cyclic guanosine monophosphate adenosine monophosphate synthase inhibitor RU.521 and the stimulator of interferon genes inhibitor H151 effectively suppressed interferon regulatory factor 7 activation in BV2 microglia exposed to 1-methyl-4-phenylpyridinium and inhibited transformation of mouse BV2 microglia into the neurotoxic M1 phenotype. In addition, siRNA-mediated knockdown of interferon regulatory factor 7 expression in BV2 microglia reduced the expression of inducible nitric oxide synthase, tumor necrosis factor α, CD16, CD32, and CD86 and increased the expression of the anti-inflammatory markers ARG1 and YM1. Taken together, our findings indicate that the cyclic guanosine monophosphate adenosine monophosphate synthase-stimulator of interferon genes-interferon regulatory factor 7 pathway plays a crucial role in the pathogenesis of Parkinson's disease.

Mitigation of the toxic effects of nitrite: Role and mechanism of isoleucine in mitigating mitochondrial DNA leakage-induced inflammation in grass carp (Ctenopharyngodon idella) under nitrite exposure

The physiological and growth processes of fish are closely associated with their surrounding environment. This study investigated the role and underlying mechanisms of isoleucine (Ile) in alleviating mitochondrial DNA (mtDNA) leakage-induced inflammation in grass carp under nitrite exposure. Grass carp were fed six experimental diets containing different Ile levels (0.00, 3.00, 6.00, 9.00, 12.00 and 15.00 g/kg) for 9 weeks, followed by a 96-hour nitrite exposure trial. Ile supplementation mitigated the deterioration of blood parameters including glutamic oxaloacetic transaminase (GOT), glutamic alanine transaminase (GPT), glucose, cortisol and lactate dehydrogenase (LDH) induced by nitrite exposure. Additionally, Ile enhanced its transport to the liver and mitochondria, as well as increased metabolism of Ile in mitochondria. Histological analyses revealed that Ile mitigated nitrite exposure-induced liver damage and mitochondrial cristae disruption. Furthermore, Ile preserved the mitochondrial cristae homeostasis by upregulating key proteins involved in mitochondrial structure maintenance, while inhibiting mtDNA leakage. Mechanistically, Ile attenuated mtDNA leakage-induced inflammation under nitrite exposure associated with the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-Stimulator of Interferon Genes (STING) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) pathways. These findings highlight the protective role of Ile in reducing inflammation triggered by environmental nitrite exposure, offering new insights into aquatic toxicology, and determined that Ile concentration of 11.13 g/kg diet could be optimal for mitigating nitrite-induced stress in grass carp, providing a theoretical basis for formulating anti- nitrite stress diets in aquaculture.

Inhibition of the cGAS-STING pathway: contributing to the treatment of cerebral ischemia-reperfusion injury

The cGAS-STING pathway plays an important role in ischemia-reperfusion injury in the heart, liver, brain, and kidney, but its role and mechanisms in cerebral ischemia-reperfusion injury have not been systematically reviewed. Here, we outline the components of the cGAS-STING pathway and then analyze its role in autophagy, ferroptosis, cellular pyroptosis, disequilibrium of calcium homeostasis, inflammatory responses, disruption of the blood-brain barrier, microglia transformation, and complement system activation following cerebral ischemia-reperfusion injury. We further analyze the value of cGAS-STING pathway inhibitors in the treatment of cerebral ischemia-reperfusion injury and conclude that the pathway can regulate cerebral ischemia-reperfusion injury through multiple mechanisms. Inhibition of the cGAS-STING pathway may be helpful in the treatment of cerebral ischemia-reperfusion injury.

Berberine alleviates tendinopathy by suppressing the cGAS-STING pathway and Relieving ferroptosis

Berberine, a key bioactive component of Coptis rhizome, has been extensively studied for its therapeutic effects on various diseases. This research aimed to investigate the potential benefits of berberine in treating tendinopathy and to elucidate the underlying mechanisms through animal and laboratory studies. Our findings indicated that berberine effectively treated type I collagenase-induced tendinopathy in rats, confirmed by cellular-level validation. At the molecular level, berberine reduced the activation of the cGAS-STING signaling pathway and decreased the accumulation of malondialdehyde (MDA) and reactive oxygen species (ROS) in both animal models and cell cultures. Additionally, berberine upregulated the expression of glutathione (GSH) and glutathione peroxidase 4 (GPX4) in tissues. These results suggested that berberine alleviated ferroptosis via the cGAS-STING pathway, thus exerting therapeutic effects on tendinopathy. To validate these findings further, we administered the ferroptosis inducer Imidazole Ketone Erastin (IKE) to evaluate the effects of berberine. IKE significantly diminished the therapeutic effects of berberine on tendinopathy, as indicated by the previously mentioned markers. Thus, berberine mitigated ferroptosis by inhibiting the cGAS-STING pathway, highlighting its potential in managing tendinopathy.

Microglial phagocytosis and regulatory mechanisms: Key players in the pathophysiology of depression

Depression is a globally prevalent emotional disorder with a complex pathophysiology. Microglia are resident immune cells in the central nervous system, playing crucial roles in regulating inflammation, synaptic plasticity, immune phagocytosis, and other functions, thereby exerting significant impacts on neuropsychiatric disorders like depression. Increasing research indicates that abnormal phagocytic function of microglia in the brain is involved in depression, showing excessive or insufficient phagocytosis in different states. Here, we have provided a review of the signaling molecules involved in microglial phagocytosis in depression, including "eat me" signals such as phosphatidylserine (PS), complement, and "don't eat me" signals such as CD47, CD200 and related receptors. Furthermore, we discuss the regulatory effects of existing pharmaceuticals and dietary nutrients on microglial phagocytosis in depression, emphasizing the need for tailored modulation based on the varying phagocytic states of microglia. This review aims to facilitate a deeper understanding of the role of microglial phagocytosis in depression and provide a roadmap for potential therapeutic strategies for depression targeting microglial phagocytosis.

Design, synthesis, and activity evaluation of novel STING inhibitors based on C170 and H151

Stimulating the STING signaling pathway for immune system activation is considered a promising strategy for cancer treatment. However, activating the STING pathway can lead to adverse effects, as aberrant activation or specific mutations in STING may result in autoimmune and inflammatory diseases. Therefore, the development of STING inhibitors is equally important. In this study, we first introduced hydroxyl groups into the STING inhibitors C170 and H151, creating functional sites for further modification. Then the introduction of various substituents resulted in the identification of more potent inhibitors, Y2 and HY2, which effectively suppressed the activation of the STING pathway in THP1 and RAW264.7 cells. Compounds Y2 and HY2 demonstrated potent anti-inflammatory effects in mice cisplatin-induced acute kidney injury models by inhibiting the STING pathway. Collectively, Y2 and HY2 warrant further investigation as novel anti-inflammatory agents.

Alternative cGAS signaling promotes herpes simplex encephalitis

During infection, foreign DNA is sensed by cyclic GMP-AMP synthase (cGAS) leading to the production of cGAMP, STING-dependent type I interferon and proinflammatory cytokine expression, and autophagy. To prevent a response to self-DNA, cGAS activity is tightly regulated. Dysregulation of cGAS underpins interferonopathies, such as Aicardi-Goutières syndrome, as well as Lupus and neurodegenerative diseases like Parkinson's disease. Thus, cGAS and its product cGAMP are therapeutic targets. However, if cGAS functions independently of cGAMP signaling is undefined. Here, we identified an alternative signaling pathway that cGAS engages independent of cGAMP synthesis. We demonstrate that alternative cGAS signaling promotes hyperexpression of CXCL1 and enhanced neutrophil recruitment that facilitates viral dissemination during herpes simplex encephalitis. Our study reports of an alternative cGAS response independent of cGAMP, highlighting a previously uncharacterized scaffold function for cGAS.

Tanshinone IIA alleviates myocarditis in Trex1-D18N lupus-like mice by inhibiting the interaction between STING and SEC24C

The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway serves as a crucial component of the innate immune defense, playing a vital role in combating pathogen invasion. However, its dysregulation or abnormal activation can trigger the development of autoimmune diseases. This study demonstrated that Tanshinone IIA, a major lipid-soluble component of Salvia miltiorrhiza Bunge, can effectively inhibit the activation of the cGAS-STING signaling pathway. Mechanistically, Tanshinone IIA inhibits the transport of STING from the ER to the Golgi apparatus by weakening the interaction between STING and SEC24C, thereby preventing the activation of the cGAS-STING signaling pathway. Furthermore, Tanshinone IIA significantly ameliorated myocardial inflammation in WT and Trex1D18N/D18N mice. Our research indicates that Tanshinone IIA shows potential therapeutic value in alleviating autoimmune diseases by effectively inhibiting the abnormal activation of the cGAS-STING pathway.

Therapeutic targeting the cGAS-STING pathway associated with protein and gene: An emerging and promising novel strategy for aging-related neurodegenerative disease

Neurodegenerative diseases (NDDs) represent a rapidly escalating global health challenge, contributing significantly to the worldwide disease burden and posing substantial threats to public health systems across nations. Among the many risk factors for neurodegeneration, aging is the major risk factor. In the context of aging, multiple factors lead to the release of endogenous DNA (especially mitochondrial DNA, mtDNA), which is an important trigger for the activation of the cGAS-STING innate immune pathway. Recent studies have identified an increasing role for activation of the cGAS-STING signaling pathway as a driver of senescence-associated secretory phenotypes (SASPs) in aging and NDDs. The cGAS-STING pathway mediates the immune sensing of DNA and is a key driver of chronic inflammation and functional decline during the aging process. Blocking cGAS-STING signaling may reduce the inflammatory response by preventing mtDNA release and enhancing mitophagy. Targeted inhibition of the cGAS-STING pathway by biological macromolecules such as natural products shows promise in therapeutic strategies for age-related NDDs. This review aims to systematically and comprehensively introduces the role of the cGAS-STING pathway in age-related NDDs in the context of aging while revealing the molecular mechanisms of the cGAS-STING pathway and its downstream signaling pathways and to develop more targeted and effective therapeutic strategies for NDDs.

Dual targeted ferritin-based delivery system blocks the crosstalk between cancer cells and cancer-associated fibroblasts to potentiate immunotherapy of colorectal cancer

The crosstalk between cancer cells and cancer-associated fibroblasts (CAFs) plays a pivotal role in maintaining immunosuppressive tumor microenvironment (iTME) and promoting tumor progression and metastasis. Herein, we first verify that the presence of CAFs significantly promotes colorectal cancer progression and causes an iTME in mouse model and publicly available single-cell data. Then, we constructed a ferritin-based dual-targeting delivery system, named HFAI (mHFn-FAPI@ATMi/ICG), to prevent communications between cancer cells and CAFs to enhance colorectal cancer immunotherapy. Indeed, mouse-derived heavy chain ferritin (mHFn) was modified with fibroblast activation protein-α inhibitor (FAPI) to endow it dual targeting capability. In tumor cells, photosensitizer indocyanine green (ICG)-mediated photothermal therapy (PTT) and photodynamic therapy (PDT), together with ataxia-telangiectasia mutated inhibitors (ATMi)-mediated DNA repair inhibition, triggered DNA damage accumulation, activated cGAS/STING signaling pathway. Whereas in CAFs, ICG-mediated PTT/PDT eradicated CAFs, while ATMi normalized CAFs. The activation of the cGAS/STING pathway and the elimination of CAFs reshaped the iTME, promoted immune cell infiltration, and enhanced the immunotherapy of CAFs-rich tumors. Furthermore, HFAI serves as a promising probe for identifying CAFs-rich peritoneal metastasis tissues and enabling near-infrared fluorescence-guided accurate resection. Taken together, this dual-targeted nanocomposites showed a remarkably synergistic therapy effect against colorectal cancer by modulating tumor-stromal crosstalk.

Disruption of cholesterol homeostasis triggers NLRP3-cGAS-STING axis-dependent hepatic fibrosis and honokiol intervention effects

BACKGROUND

Maintaining cholesterol homeostasis is crucial for sustaining human health and physiological function. Although the detrimental effects of chronic cholesterol overload on hepatic injury and fibrosis are well documented, the molecular mechanisms driving this pathology remain incompletely understood.

PURPOSE

This study investigates the mechanistic role of chronic cholesterol overload in driving liver fibrosis and evaluates the therapeutic efficacy of honokiol as a targeted intervention.

STUDY DESIGN AND METHODS

High-cholesterol models induced by cholesterol and 25-hydroxycholesterol in human HepG2 cells or induced by cholesterol crystals in mouse bone marrow-derived macrophages were established. We also examined the effect of cholesterol on the livers of mice following a 20-week regimen of high-cholesterol diets.

RESULTS

Excess cholesterol interfered with normal cholesterol metabolism both in vitro and in vivo, and led to liver damage and fibrosis in vivo. Further research showed that cholesterol exposure triggered NLRP3 inflammasome activation and programmed cell death called pyroptosis; induced an increase in mitochondrial ROS and a disruption of intracellular redox homeostasis, followed by the opening of the mitochondrial permeability transition pore; and finally induced cellular DNA damage, resulting in the translocation of the double-stranded DNA fragment into the cytoplasm and the activation of the DNA-sensing adaptor STING. The activation of the NLRP3-cGAS-STING axis initiated the downstream cascade reaction and up-regulated the expression of pro-inflammatory cytokines, including IL-1β, TNF-α, and IFN-β, thus facilitating liver damage and fibrosis. Furthermore, honokiol, an active ingredient in Magnolia officinalis, could alleviate liver damage and fibrosis by blocking NLRP3 inflammasome activation, pyroptosis, and the cGAS-STING pathway.

CONCLUSION

Systematic evidence shows that cholesterol induces liver fibrosis through the activation of the NLRP3-cGAS-STING signaling axis and that honokiol demonstrates interventional efficacy in mitigating this process.

cGAS-STING and neurodegenerative diseases: A molecular crosstalk and therapeutic perspective

Neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic Lateral Sclerosis (ALS), Multiple Sclerosis (MS) and Frontotemporal Dementia (FTD) share key pathological features, including neuroinflammation, oxidative stress, mitochondrial dysfunction, autophagic dysfunction, and DNA damage. By identifying cytosolic DNA and triggering the type I interferon response, the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway regulates neuroinflammation. Dysregulated cGAS-STING signaling has been linked to neuroinflammation and neuronal degeneration across multiple neurodegenerative conditions. In many neurodegenerative disorders, neuroinflammation is mediated by the cGAS-STING pathway. Mitochondrial malfunction and impaired autophagy cause cytosolic DNA buildup in Huntington's, Parkinson's, and Alzheimer's diseases, which activates cGAS-STING and drives chronic inflammation. This pathway is triggered by TDP-43 pathology and nucleic acid dysregulation in ALS and FTD, which leads to neuronal destruction. Both central demyelination and peripheral immunological responses are linked to cGAS-STING activation in multiple sclerosis. Various inhibitors, such as RU.521, H-151, and naturally occurring compounds like metformin, potentially attenuate cGAS-STING-mediated neuroinflammation and associated pathologies. H-151 significantly decreased the expression of pro-inflammatory markers in murine macrophage J774 cells activated with cGAMP: TNF-α by 68 %, IFN-β by 84 %, and CXCL10 by 96 %. cGAS-STING inhibitors target neuroinflammation, offering a disease-modifying approach unlike current symptomatic treatments. However, challenges like blood-brain barrier penetration, off-target effects, and immune suppression hinder clinical translation, necessitating optimized drug delivery and immune modulation. With a focus on its potential for future clinical applications, this review explores the role of the cGAS-STING pathway in neurodegeneration and new treatment approaches.

Embracing cancer immunotherapy with manganese particles

A substance integral to the sustenance and functionality of virtually all forms of life is manganese (Mn), classified as an essential trace metal. Its significance lies in its pivotal role in facilitating metabolic processes crucial for survival. Additionally, Mn exerts influence over various biological functions including bone formation and maintenance, as well as regulation within systems governing immunity, nervous signaling, and digestion. Manganese nanoparticles (Mn-NP) stand out as a beacon of promise within the realm of immunotherapy, their focus honed on intricate mechanisms such as triggering immune pathways, igniting inflammasomes, inducing immunogenic cell death (ICD), and sculpting the nuances of the tumor microenvironment. These minuscule marvels have dazzled researchers with their potential in reshaping the landscape of cancer immunotherapy - serving as potent vaccine enhancers, efficient drug couriers, and formidable allies when paired with immune checkpoint inhibitors (ICIs) or cutting-edge photodynamic/photothermal therapies. Herein, we aim to provide a comprehensive review of recent advances in the application of Mn and Mn-NP in the immunotherapy of cancer. We hope that this review will display an insightful view of Mn-NPs and provide guidance for design and application of them in immune-based cancer therapies.

Zebrafish fkbp5 attenuates antiviral innate immunity by autophagic degradation of transcription factor irf7

Activation of the type I interferon (IFN-I) signaling pathway is crucial for protecting host cells against viral infections. IFN-I production requires the transcription factors IFN regulatory factor 3 (IRF3) and IRF7, and its regulation must be finely tuned to both combat infection effectively and prevent excessive immunopathology. Here, we report that selective autophagy mediated by zebrafish FK506-binding protein 5 (Fkbp5), a PPIase (peptidyl-prolyl isomerase) promotes the degradation of Irf7 and Irf3, thereby inhibiting virus-induced type I IFN production. Quantitative real-time reverse-transcription polymerase chain reaction experiments indicate that zebrafish fkbp5 is induced by viral infection. Moreover, disrupting fkbp5 in AB-line zebrafish using CRISPR/Cas9 enhances survival rates and reduces viral messenger RNA levels compared with wild-type zebrafish. In cell culture, using promoter analysis and quantitative real-time reverse-transcription polymerase chain reaction, we found fkbp5 overexpression significantly attenuates cellular antiviral capacity and facilitates viral proliferation. Mechanistically, we found that fkbp5 inhibits Irf3/7-induced IFN activation, which depends on the binding of Fkbp5 to the Irf3 or IRF association domain of Irf7 via co-immunoprecipitation and Western blot assays. Furthermore, Fkbp5 induces the autophagic degradation of Irf3 and Irf7 independent of its PPIase activity. Blocking autophagy in vivo and in vitro restores the regulation of the RLR (RIG-I-like receptor) pathway by fkbp5. These findings reveal a critical role for zebrafish fkbp5 in suppressing the activation of Irf7 and Irf3 for IFN signaling and antiviral immune responses.

Ketogenesis instigates immune suppression in enzalutamide resistant prostate cancer via OTUD7B β-hydroxybutyrylation

Next-generation androgen receptor inhibitors are the primary treatment for metastatic prostate cancer. Unfortunately, the majority of patients rapidly develop resistance. Resistance to enzalutamide has been linked to the emergence of an immunosuppressive tumor, although the underlying mechanisms remain poorly understood. In this study, we observed a marked overexpression of enzymes involved in the ketogenic pathway in enzalutamide-induced castration-resistant prostate cancer, which contributed to immune desertification and resistance to immunotherapy. Mechanistically, upregulation of the ketogenic pathway led to the accumulation of β-hydroxybutyrate, which promoted β-hydroxybutyrylation of the cell cycle-regulated deubiquitinase OTUD7B at lysine 511. This modification impaired the degradation of APC/C substrates, resulting in a subsequent reduction in cytoplasmic double-stranded DNA accumulation, thereby attenuating cGAS-STING activation and interferon expression. These findings shed light on the metabolic adaptations and immune escape driven by androgen receptor signaling inhibitors, potentially informing the development of more effective and durable therapeutic approaches in the near future.

Tollip deficiency enhances mitophagy and reduces STING activation in influenza A virus-infected mice

Toll-interacting protein (Tollip) is an intracellular adaptor protein with diverse functions including regulation of autophagy of mitochondria-mitophagy. Tollip deficiency promotes viral infection, but whether mitophagy is involved remains unclear. We sought to determine if mitophagy and associated signaling such as mitochondrial DNA (mtDNA) release and activation of stimulator of interferon genes (STING) contribute to worsened viral infection due to Tollip deficiency. Wild-type and Tollip knockout (KO) C57/BL6 mice were intranasally infected with influenza A virus (IAV), and then treated with or without a STING agonist 2'3'cGAMP for 4 d. PINK1 (an initiator of mitophagy) KO mouse tracheal epithelial cells (mTECs) or PINK1 KO mice were infected with IAV to reveal the role of mitophagy in viral infection. In IAV-infected mice, Tollip deficiency enhanced lung mitophagy (more PINK1 and BNIP3L, but less p62), and decreased release of mtDNA. Furthermore, Tollip deficiency suppressed STING activation and the antiviral response (eg IFN-β and MX1), and increased viral load. In IAV-infected Tollip KO mice, 2'3'cGAMP activated STING and increased antiviral response coupled with less virus. PINK1-deficient mice increased lung release of mtDNA and augmented STING activation and antiviral responses. PINK1 deficiency in mTECs increased STING activation and significantly decreased the viral load. Our findings suggest that enhanced mitophagy due to Tollip deficiency reduces mtDNA release and STING activation during viral infection, resulting in decreased antiviral responses. Reduction of mitophagy and/or STING activation may open novel avenues for therapeutic intervention in human subjects with Tollip deficiency and viral infection.

Faecalibacterium Prausnitzii extracellular vesicles regulating macrophage differentiation via homologous recombination repair in colitis model

Inflammatory Bowel Disease (IBD) is characterized by chronic inflammation influenced by the depletion of beneficial gut microbiota, a critical factor in disease onset and progression. This study investigates the therapeutic potential of extracellular vesicles (EVs) derived from Faecalibacterium prausnitzii (F.p EVs), a commensal bacterium whose reduction is linked to IBD. Our research demonstrates that F.p EVs are preferentially taken up by macrophages, where they exert their anti-inflammatory effects through the enhancement of homologous recombination (HR) repair mechanisms. Specifically, F.p EVs upregulate the expression of key proteins involved in HR repair, such as BRCA1 and BRCA2, thereby reducing DNA damage and inhibiting the cGAS-STING pathway, which is central to the inflammatory response. This modulation of macrophage function results in decreased pro-inflammatory cytokine production and enhanced intestinal barrier integrity. By elucidating these mechanisms, our study provides a clear understanding of how F.p EVs can be used to target fundamental aspects of IBD pathology, laying the groundwork for the development of more effective and targeted therapies.

Alcoholic cirrhosis-associated immune dysfunction: What does it imply for us?

Alcoholic cirrhosis is a leading cause of chronic advanced liver disease. With the gradual eradication of viral hepatitis and the rising levels of alcohol consumption, the incidence of alcoholic cirrhosis is expected to increase steadily. Alcohol is primarily metabolized in the gastrointestinal tract, producing toxic metabolites that enter the portal vein circulation and are subsequently transported to the liver. Excessive alcohol intake activates the microsomal ethanol oxidation system and disrupts the intestinal microbiota-driven microenvironment dictated by intestinal microbiota, and increase intestinal permeability, all of which trigger severe systemic inflammatory responses and impaired immune function. This phenomenon, known as cirrhosis-associated immune dysfunction (CAID), is closely linked to the severity of cirrhosis and can significantly influence disease progression, potentially leading to multi-organ failure. This narrative review sheds light on the relationship between alcoholic cirrhosis and CAID, focusing on tailored interventions to modify immune response and modulate gut microbiota composition in hopes of mitigating the development and deterioration of alcoholic cirrhosis.

AUP1 and UBE2G2 complex targets STING signaling and regulates virus-induced innate immunity

Stimulator of interferon genes (STING) is an endoplasmic reticulum (ER) signaling adaptor that is essential for the host immune response triggered by DNA pathogens. Precise regulation of STING is crucial for maintaining a balanced immune response and preventing harmful autoinflammation. Activation of STING requires its translocation from the ER to the Golgi apparatus. However, the mechanisms that maintain STING in its resting state remain largely unclear. Here, we find that deficiency of the ancient ubiquitous protein 1 (AUP1) causes spontaneous activation of STING and enhances the expression of type I interferons (IFNs) under resting conditions. Furthermore, deficiency of UBE2G2, a cofactor of AUP1, also promotes the abnormal activation of STING. AUP1 deficiency significantly enhances STING signaling induced by DNA virus, and AUP1 deficiency exhibits increased resistance to DNA virus infection in vitro and in vivo. Mechanistically, AUP1 may form a complex with UBE2G2 to interact with STING, preventing its exit from the ER membrane. Notably, infection with the RNA virus vesicular stomatitis virus (VSV) promotes the accumulation of lipid droplets (LDs) and AUP1 proteins. Additionally, AUP1 deficiency markedly inhibits the replication of VSV because AUP1 deficiency reduces lipid accumulation and alters the expression of lipid metabolism genes, such as carnitine palmitoyltransferase 1A (CPT1A), monoglyceride lipase (MGLL), and sterol regulatory element-binding transcription factor 1 (SREBF1). This study uncovers the essential roles of AUP1 in the STING signaling pathway and lipid metabolism pathway, highlighting its dual role in regulating virus replication.IMPORTANCEThe stimulator of interferon genes (STING) signaling cascade plays an essential role in coordinating innate immunity against DNA pathogens and autoimmunity. Precise regulation of the innate immune response is essential for maintaining homeostasis. In this study, we demonstrate that ancient ubiquitous protein 1 (AUP1) and UBE2G2 act as negative regulators of the innate immune response by targeting STING. Notably, AUP1 interacts with STING to retain STING in the endoplasmic reticulum (ER), preventing STING translocation and thereby limiting STING signaling in the resting state. In addition, deficiency of AUP1 markedly inhibits the replication of DNA virus and RNA virus. Our findings provide new insights into the regulation of STING signaling and confirm AUP1 has a dual role in regulating virus replication.

Cholesterol biosynthesis induced by radiotherapy inhibits cGAS-STING activation and contributes to colorectal cancer treatment resistance

Radiotherapy-induced DNA damage can lead to apoptotic cell death and trigger an anti-tumor immune response via the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway, which senses cytoplasmic double-stranded DNA. However, radiotherapy resistance poses a significant challenge in treating cancers, including colorectal cancer (CRC). Understanding the mechanisms underlying this resistance is crucial for developing effective therapies. Here we report that radiotherapy enhances cholesterol synthesis, which subsequently inhibits the cGAS-STING pathway, leading to radiotherapy resistance. Mechanistically, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) levels increase rapidly in response to radiation, resulting in increased cholesterol synthesis. This increased cholesterol sequesters STING in the endoplasmic reticulum, hindering its activation and downstream interferon signaling. Elevated HMGCR and cholesterol levels correlate with poor prognosis and reduced response to radiation therapy in patients with CRC. Importantly, pharmacological inactivation of HMGCR significantly enhanced radiotherapy responsiveness in animal models, dependent on cGAS-STING signaling-mediated anti-tumor responses. Our findings reveal that radiotherapy-induced cholesterol inhibits cGAS-STING signaling, facilitating tumor immune escape. Therefore, combining statins with radiotherapy represents a promising therapeutic strategy for treating CRC.

Advances in polymer nanomaterials targeting cGAS-STING pathway for enhanced cancer immunotherapy

Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway has been recognized as a promising target for cancer immunotherapy. Although various STING agonists have been developed, their clinical applications are still severely impeded by various issues, such as non-specific accumulation, adverse effects, rapid clearance, etc. In recent years, the emergence of nanomaterials has profoundly revolutionized STING agonists delivery, which promote tumor-targeted delivery, boost the immunotherapeutic effects and reduce systemic toxicity of STING agonists. In particular, polymer nanomaterials possess inherent advantages including controllable structure, tunable function and degradability. These properties afford them the capacity to serve as delivery vehicles for small-molecule STING agonists. Furthermore, the superior characteristics of polymer nanomaterials can enable their utilization as a novel STING agonist to stimulate anti-tumor immunity. In this review, the molecular mechanisms of cGAS-STING pathway activation are discussed. The recent development of small-molecules STING agonists is described. Then polymer nanomaterials are discussed as carriers for STING agonists in cancer immunotherapy, including polymersomes, polymer micelles, polymer capsules, and polymer nanogels. Additionally, polymer nanomaterials are identified as a novel class of STING agonists for efficient cancer immunotherapy, encompassing both polymer materials and polymer-STING agonists conjugates. The review also presents the combination of polymer-based cGAS-STING immunotherapy with chemotherapy, radiotherapy, phototherapy (both photodynamic and photothermal), chemodynamic therapy, and other therapeutic strategies. Furthermore, the discussion highlights recent advancements targeting the cGAS-STING pathway in clinically approved polymer nanomaterials and corresponding potent innovations. Finally, the potential challenges and perspectives of polymer nanomaterials for activating cGAS-STING pathway are outlined, emphasizing the critical scientific issue and hoping to offer guidance for their clinical translation.

Mitochondria-dependent innate immunity: A potential therapeutic target in Flavivirus infection

Mitochondria, known as the powerhouse of cells, play a crucial role in host innate immunity during flavivirus infections such as Dengue, Zika, West Nile, and Japanese Encephalitis Virus. Mitochondrial antiviral signaling protein (MAVS) resides on the outer mitochondrial membrane which is triggered by viral RNA recognition by RIG-I-like receptors (RLRs). This activation induces IRF3 and NF-κB signaling, resulting in type I interferon (IFN) production and antiviral responses. Upon flavivirus infection, mitochondrial stress and dysfunction may lead to the release of mitochondrial DNA (mtDNA) into the cytoplasm, which serves as a damage-associated molecular pattern (DAMP). Cytosolic mtDNA is sensed by cGAS (cyclic GMP-AMP synthase), leading to the activation of the STING (Stimulator of Interferon Genes) pathway to increase IFN production and expand inflammation. Flaviviral proteins control mitochondrial morphology by controlling mitochondrial fission (MF) and fusion (MFu), disrupting mitochondrial dynamics (MD) to inhibit MAVS signaling and immune evasion. Flaviviral proteins also cause oxidative stress, resulting in the overproduction of reactive oxygen species (ROS), which triggers NLRP3 inflammasome activation and amplifies inflammation. Additionally, flaviviruses drive metabolic reprogramming by shifting host cell metabolism from oxidative phosphorylation (OxPhos) to glycolysis and fatty acid synthesis, creating a pro-replicative environment that supports viral replication and persistence. Thus, the present review explores the complex interaction between MAVS, mtDNA, and the cGAS-STING pathway, which is key to the innate immune response against flavivirus infections. Understanding these mechanisms opens new avenues in therapeutic interventions in targeting mitochondrial pathways to enhance antiviral immunity and mitigate viral infection.

Design, Synthesis, and Biological Evaluation of Selective STING Synergists That Enhance cGAMP-STING Pathway Activation without Inherent Agonist Activity

The cGAS-STING pathway is pivotal for innate immunity and antitumor responses. However, the challenge of selectively targeting the diseased tissue without harming the healthy tissue has impeded the development of STING agonists. In this article, we tackle this issue by developing novel STING synergists that target the STING C-terminal domain pocket. Our findings indicate that agonist 12B can boost the cGAMP-STING pathway synergistically. Through reverse optimization of 12B, we synthesized three series of compounds, with compounds 55, 66, and 67 emerging as selective STING synergists that amplify cGAMP-induced pathway activation without inherent agonist properties. Compound 67 emerged as the most potent (EC50 = 20.53 μM), displaying a broad binding affinity across STING-CTD alleles and potent antitumor efficacy in vivo. Notably, it exhibited excellent safety profiles in both in vitro and in vivo models, along with favorable pharmacokinetics. These findings highlight the therapeutic potential of novel STING synergists for cancer immunotherapy.

Deciphering cGAS-STING signaling: implications for tumor immunity and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most prevalent form of primary liver cancer and poses a significant global health challenge due to its rising incidence and associated mortality. Recent advancements in understanding the cytosolic DNA sensing, the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway have illuminated its critical role in the immune response to HCC. This narrative review deciphers the multifaceted involvement of cGAS-STING in HCC, mainly its function in detecting cytosolic DNA and initiating type I interferon (IFN-I) responses, which are pivotal for antitumor immunity. This immune response is crucial for combating pathogens and can play a role in tumor surveillance. In the context of HCC, the tumor microenvironment (TME) can exhibit immune resistance, which complicates the effectiveness of therapies like immune checkpoint blockade. However, activation of the cGAS-STING pathway has been shown to stimulate antitumor immune responses, enhancing the activity of dendritic cells and cytotoxic T lymphocytes. There is ongoing research into STING agonists as a treatment strategy for HCC, with some studies indicating promising results in prolonging survival and enhancing the immune response against tumors. By summarizing current knowledge and identifying research gaps, this review aims to provide a comprehensive overview of cGAS-STING signaling in HCC and its future directions, emphasizing its potential as a therapeutic target in the fight against HCC. Understanding these mechanisms could pave the way for innovative immunotherapeutic approaches that enhance the efficacy of existing treatments and improve patient prognosis.

The cGAS-STING pathway promotes acute ischemia-induced neutropoiesis and neutrophil priming in the bone marrow

Our previous work demonstrated that the DNA-sensing receptor cyclic GMP-AMP synthase (cGAS) negatively affects post-infarct repair by promoting pro-inflammatory macrophages. However, whether cGAS and its downstream partner STING (Stimulator of Interferon Genes) regulate neutrophil production and function in the context of acute myocardial ischemia remains unclear. This study investigated the role of the cGAS-STING pathway in neutropoiesis (neutrophil production and differentiation) and examined whether ischemia primes neutrophils in the bone marrow via this pathway, enhancing their functionality and contributing to cardiac inflammatory injury. Using myocardial infarction (MI) models in wild-type (WT), Cgas-/-, and Sting-/- mice, we analyzed neutrophils from the bone marrow, peripheral blood, and infarcted tissue. Additionally, we generated neutrophil-specific conditional knockouts of Cgas and performed adoptive transfer experiments with Cgas-deficient neutrophils. RNA sequencing revealed that ischemia increased neutrophil production in the bone marrow and activated pathways involved in cytokine signaling, phagocytosis, chemotaxis, and degranulation. Inhibiting the cGAS-STING pathway reduced neutrophil production by decreasing lineage committed neutrophil precursors including early neutrophil precursors (eNP) and preNeu and downregulated ischemia-induced pathways. Neutrophil conditional Cgas deletion or adoptive transfer of Cgas-deficient neutrophils improved survival but did not significantly impact ischemia-induced remodeling. In conclusion, we demonstrate for the first time that ischemia enhanced neutrophil functionality before recruitment to infarcted tissue, and the cGAS-STING pathway played an important role in neutrophil production and priming. Furthermore, our findings demonstrate a neutrophil-specific role of cGAS in promoting cardiac rupture and mortality in MI. This study provides a more comprehensive understanding of the cGAS-STING pathway in acute ischemia and may support the translation of cGAS-STING modulators, an emerging therapeutic field.

Cell-free mitochondrial DNA may predict the risk of post-operative complications and outcomes in surgical aortic valve replacement patients

Surgical aortic valve replacement (AVR) is the standard of care for severe aortic valve disease; however, post-operative complications continue to pose challenges. Inflammation caused by increased release of cell-free mitochondrial DNA (cf-mtDNA) during surgery may be a contributing factor. The aim of this pilot study was to investigate the relationship between cf-mtDNA release and the risk of inflammatory-mediated post-operative complications in adult AVR patients. Plasma was collected from patients undergoing an AVR with cardiopulmonary bypass (CPB) at baseline, intra-operatively and post ICU admission at 6, 12 and 18 h. Cf-mtDNA was quantified and inflammatory biomarker expression in leukocytes and plasma was assessed. Cf-mtDNA levels increased 16-fold at the end of CPB with a corresponding increase in average fragment size. Cf-mtDNA levels may be associated with post-operative bleeding, infection, hepatic failure and hospital length of stay. Gene expression and plasma analysis revealed altered levels of markers associated with inflammation and innate immune responses. Several markers were associated with post-operative complications and outcomes. Our results indicate that cf-mtDNA levels, including average fragment sizes, are increased following initiation of CPB in AVR patients, and may be associated with post-operative complications and outcomes. However, larger studies are needed to validate these findings.

Exosomes derived from African swine fever virus-infected pigs mediate immune responses through NF-κB and JAK-STAT signaling pathways

African swine fever (ASF) virus (ASFV) is an infectious disease that affects the pig industry, causing up to 85 % morbidity and 100 % mortality. To date, there are no available vaccines against ASFV. Exosomes are extracellular vesicles that are released from most cell types. Exosomes carry components such as nucleic acids, lipids, and proteins that play a vital role in cell-to-cell communication. This study investigated the effect of exosomes derived from the serum of ASFV-infected pigs on a porcine macrophage cell line. Exosomes derived from the serum of pigs infected with ASFV contained ASFV structural proteins (p30 and p72). Expression levels of interferon (IFN)-α, IFN-γ, IL-6, and CXCL8 in porcine macrophage cells were affected by exposure to exosomes derived from the serum of ASFV-infected pigs. Nuclear factor-κB (NF-κB) and Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway play an important role in the immune response to ASFV infection. Exosomes derived from ASFV-infected pigs affected mRNA and protein levels of NF-κB, tank binding kinase 1 (TBK1), JAK1, JAK2, and STAT1, suggesting that exosomes derived from ASFV-infected pigs mediate antiviral response by modulating the expression of inflammatory cytokines and activity of the NF-κB and JAK-STAT signaling pathways. The present study provides novel information about the immunomodulatory effects of exosome derived from pigs infected with ASFV, improving our understanding of ASFV pathogenesis and the host immune response to ASFV infection.

Drug screen reveals new potent host-targeted antivirals against Mpox virus

Mpox virus (MPXV), a re-emerging zoonotic threat, has caused outbreaks in non-endemic regions through respiratory, sexual, and close-contact transmission. The increased transmissibility of Clade IIb fueled the 2022 global outbreak, with 2024 Clade Ib spread in the Democratic Republic of Congo further escalating concern. Both outbreaks were declared public health emergencies by the WHO. Although tecovirimat (TPOXX) has been used off-label for Mpox, its limited effectiveness highlights the critical need for newer antivirals for MPXV. We conducted high-throughput antiviral drug screening using a host-directed kinase inhibitor library composed of 2,750 compounds against 2022 Clade IIb MPXV. Our primary screen identified 138 compounds preventing MPXV cytopathic effects, including multiple inhibitors of EGFR, PI3K-mTOR, and Ras/Raf, as well as apoptosis and autophagy regulators. Secondary and tertiary screenings yielded a shortlist of potent, nontoxic antiviral compounds that inhibited MPXV replication. Three selected compounds, IRAK4-IN-6, SM-7368, and KRAS inhibitor-10, reduced MPXV-induced cell death in primary human epidermal keratinocytes. IRAK4-IN-6 and SM-7368 were also found to modulate NF-κB and STING signaling. Furthermore, these compounds were found effective in reducing skin lesions and viral burden in a mouse model of MPXV skin infection. Together, our study reveals new classes of antiviral compounds against MPXV, offering promising candidates for future clinical development.

ATP2A2 regulates STING1/MITA-driven signal transduction including selective autophagy

STING1/MITA not only induces innate immune responses but also triggers macroautophagy/autophagy to selectively degrade signaling molecules. However, the molecular mechanisms regulating STING1-mediated selective autophagy remain unclear. Here, we first report that ATP2A2 directly interacts with STING1, regulating STING1-mediated innate immune response by modulating its polymerization and trafficking, thereby inhibiting DNA virus infection. Notably, while screening for reticulophagy receptors involved in STING1-mediated selective autophagy, we identified SEC62 as an important receptor protein in STING1-mediated reticulophagy. Mechanistically, SEC62 strengthens its interaction with STING1 upon activation and concurrently facilitates STING1-mediated reticulophagy upon starvation, which are dependent on ATP2A2. Furthermore, knocking down SEC62 in WT cells inhibits STING1-mediated MAP1LC3B/LC3B lipidation and autophagosome formation, an effect that is lost in ATP2A2 knockout cells, suggesting that SEC62's role in STING1-mediated selective autophagy is ATP2A2 dependent. Thus, our findings identify the reticulophagy receptor SEC62 as a novel receptor protein regulating STING1-mediated selective autophagy, providing new insight into the mechanism regarding a reticulophagy receptor in the process of STING1-induced selective autophagy.Abbrevations: aa: amino acids; AP-MS: affinity tag purification-mass spectrometry; ATP2A1: ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting 1; ATP2A2: ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting 2; ATP2A3: ATPase sarcoplasmic/endoplasmic reticulum Ca2+ transporting 3; CANX: calnexin; CCPG1: cell cycle progression 1; CGAS: cyclic GMP-AMP synthase; ctDNA: calf thymus DNA; dsRNA: double-stranded RNA; diABZI: diamidobenzimidazole; ER: endoplasmic reticulum; ERGIC: ER-Golgi intermediate compartment; EBSS: Earle's Balanced Salt Solution; EV: empty vector; FL: full length; GOLGA2/GM130: golgin A2; HSV-1: herpes simplex virus type 1; IRF3: interferon regulatory factor 3; IFNs: type I interferons; ISD: interferon stimulatory DNA; KO: knockout; MAVS: mitochondrial antiviral signaling protein; MOI: multiplicity of infection; poly(I:C): polyinosinic-polycytidylic acid; NBR1: NBR1 autophagy cargo receptor; PRR: pattern recognition receptor; reticulophagy: selective autophagic degradation of the ER; RETREG1/FAM134B: reticulophagy regulator 1; RIGI: RNA sensor RIG-I; RTN3L: reticulon 3; SEC62: SEC62 homolog, preprotein translocation factor; SeV: Sendai virus; STIM1: stromal interaction molecule 1; STING1/MITA: stimulator of interferon response cGAMP interactor 1; TBK1: TANK binding kinase 1; TEX264: testis expressed 264, ER-phagy receptor; TMX1: thioredoxin related transmembrane protein 1; VSV: vesicular stomatitis virus; VACV: vaccinia virus; ZMPSTE24: zinc metallopeptidase STE24.

Macrophage polarization in cancer and beyond: from inflammatory signaling pathways to potential therapeutic strategies

Macrophages are innate immune cells distributed throughout the body that play vital roles in organ development, tissue homeostasis, and immune surveillance. Macrophages acquire a binary M1/M2 polarized phenotype through signaling cascades upon sensing different signaling molecules in the environment, thereby playing a core role in a series of immune tasks, rendering precise regulation essential. M1/M2 macrophage phenotypes regulate inflammatory responses, while controlled activation of inflammatory signaling pathways is involved in regulating macrophage polarization. Among the relevant signaling pathways, we focus on the six well-characterized NF-κB, MAPK, JAK-STAT, PI3K/AKT, inflammasome, and cGAS-STING inflammatory pathways, and elucidate their roles and crosstalk in macrophage polarization. Furthermore, the effects of many environmental signals that influence macrophage polarization are investigated by modulating these pathways in vivo and in vitro. We thus detail the physiological and pathophysiological status of these six inflammatory signaling pathways and involvement in regulating macrophage polarization in cancer and beyond, as well as describe potential therapeutic approaches targeting these signaling pathways. In this review, the latest research advances in inflammatory signaling pathways regulating macrophage polarization are reviewed, as targeting these inflammatory signaling pathways provides suitable strategies to intervene in macrophage polarization and various tumor and non-tumor diseases.

The potential mechanisms of extracellular vesicles in transfusion-related adverse reactions: Recent advances

Blood transfusion is an irreplaceable clinical treatment. Blood components are differentiated and stored according to specific guidelines. Storage temperatures and times vary depending on the blood component, but they all release extracellular vesicles (EVs) during storage. Although blood transfusions can be life-saving, they can also cause many adverse transfusion reactions, among which the effects of EVs are of increasing interest to researchers. EVs are submicron particles that vary in size, composition, and surface biomarkers, are encapsulated by a lipid bilayer, and are not capable of self-replication. EVs released by blood cells are important contributors to pathophysiologic states through proinflammatory, coagulant, and immunosuppressive effects, which in turn promote or inhibit the associated disease phenotype. Therefore, this review explores the potential mechanisms of hematopoietic-derived EVs in transfusion-associated adverse reactions and discusses the potential of the latest proteomics tools to be applied to the analysis of EVs in the field of transfusion medicine with a view to reducing the risk of blood transfusion.

A lectin affinity plasmapheresis device removes extracellular vesicles and microRNAs from renal perfusates following controlled oxygenated rewarming of discarded donor kidneys

Kidney transplantation is considered the benchmark treatment for end-stage kidney disease patients, yet the scarcity of suitable kidneys poses a significant hindrance for patients and healthcare providers. One approach is to extend the criteria for the use of kidneys from deceased brain death and deceased circulatory death donors. Use of these organs, especially from these extended criteria donors, is associated with ischemia reperfusion injury and resultant delayed graft function as well as increased rates of allograft rejection. To lessen these complications as well as increase the time of organ viability assessment, machine perfusion has been evaluated on recovered kidneys. In this study we examined the immunogenic molecular content of perfusates from discarded organs that had undergone Controlled Oxygenated Rewarming (COR). Perfusates were analyzed for extracellular vesicles (EVs), DNA (Deoxyribonucleic acid), and microRNAs. These perfusates were then pumped over a plasma separator containing a lectin affinity resin. Following treatment, a significant diminution in extracellular vesicles, dsDNA (double-stranded DNA) associated with EVs, and microRNAs (miRNA) were observed. Specifically, in three out of the four renal perfusates analyzed there was significant removal of small EVs (<200 nm) and vesicles loaded with dsDNA (p < 0.05). Notably, depletion of larger EVs (100-500 nm) was found to be significant in all treated perfusates (p < 0.01). NanoString analysis of miRNA found 5 species potentially involved in renal dysfunction (hsa-let 7a-5p, hsa-miR-148b-3p, hsa-miR-148a-3p, hsa-miR-29b-3pb and hsa-miR-99a5p) to be significantly depleted in treated renal perfusates (p ≤ 0.05). These results support a future study incorporating this treatment method into a dynamic machine perfusion circuit to explore if reduction of these mediators is associated with improved function of retrieved kidneys.

Nano-delivery of STING agonists: Unraveling the potential of immunotherapy

The cyclic GMP-AMP synthetase-interferon gene stimulator (cGAS-STING) pathway possesses tremendous potential in immune responses, viral defense, and anti-tumor treatment. Currently, an increasing number of nanocarriers are being engineered to convey STING agonists, with the goal of booSTING the conveying capacity of cGAS-STING agonists and augment the therapeutic potency of STING agonists. In this review, we explore the mechanisms of cGAS-STING activators, the application of different nanocarriers in the STING pathway, and the application of nanocarriers in anti-tumor therapy, antiviral therapy and autoimmune diseases. Additionally, we also discuss the adverse effects of STING pathway activation and the challenges encountered in nano delivery, we hope that future research will delve into the development of new nanocarriers and the clinical translation of nanocarriers in STING-mediated immunotherapy. STATEMENT OF SIGNIFICANCE: The cyclic GMP-AMP synthetase-interferon gene stimulator (cGAS-STING) pathway possesses tremendous potential in immune responses, viral defense, and anti-tumor treatment. In this review, we first explore the activation mechanism of cGAS-STING signal pathway and the diverse array of nanocarriers that have been employed in the context of the STING pathway, such as natural carrier, lipid nanoparticles, polymeric nanoparticles, and inorganic nanoparticles, highlighting their unique properties and the challenges they present in clinical applications. Furthermore, we discuss the research progress regarding nanocarriers in STING-mediated immunotherapy, such as the application of nanocarriers in anti-tumor therapy, antiviral therapy and autoimmune diseases therapy. Finally, the side effects of STING pathway activation and the issues encountered in nano delivery will be discussed, hoping that future research will delve into the development of new nanocarriers and the clinical translation of nanocarriers in STING-mediated immunotherapy.

Dihydroartemisinin Attenuates Radiation-Induced Lung Injury by Inhibiting the cGAS/STING/NF-κB Signaling Pathway

Dihydroartemisinin (DHA) is a derivative of artemisinin, which affects inflammation, oxidative stress, and immune regulation. However, the mechanism underlying its effects remains largely unknown. This study aims to explore the mechanism by which DHA affects radiation-induced lung injury (RILI), providing new insights for lung radiotherapy. To elucidate its mechanism of action, C57BL/6 J mice were irradiated with 15 Gy whole chest. RILI was evaluated by qRT-PCR, ELISA, histology, Western blot analysis, immunohistochemistry, and RILI signaling cascade studies. In addition, small interfering RNAs were employed to knockdown cGAS proteins in the cGAS-STING signaling pathway in the human bronchial epithelium cell line (BEAS-2B). Both In Vivo and Vitro experiments were conducted to investigate the specific mechanism by which DHA alleviated RILI. We observed the activation of the cGAS-STING pathway, along with the phosphorylation of the downstream target NF-κB and an increase in inflammatory factor levels in the mouse model following radiation exposure. In the cell model, irradiation also triggered the activation of the cGAS-STING signaling pathway and its downstream targets, leading to elevated levels of inflammatory factors. Notably, knocking down the cGAS using small interfering RNA in the BEAS-2B cells significantly alleviated RILI in the cell model. Our study elucidated the mechanism of DHA reducing RILI through the cGAS/STING/NF-κB signaling pathway, and revealed that the GAS/STING/NF-κB axis may be a potential therapeutic target for RILI.

Exploring the Role of Pattern Recognition Receptors as Immunostimulatory Molecules

BACKGROUND

Pattern recognition receptors (PRRs) are the receptors of the innate immune system that play a vital role in initiating innate immune response. PRRs recognize pathogen associated molecular patterns (PAMPs) and activate immune cells through a signaling cascade. Due to this remarkable ability to recognize pathogenic microbes and elucidation of an immune response in a well-organized manner, PRR agonizts are likely to have great potential as vaccine adjuvants. Recent advancements in vaccine development raised concerns regarding the reduced immunogenicity of various vaccines, questioning the vaccine efficacy. In such cases, the use of an adjuvant becomes crucial. Understanding the structure and downstream signaling of PRRs will provide the possibility of developing a novel therapeutic approach.

METHOD

The rapidly evolving field of immunology and vaccinology, coupled with the increasing focus on PRRs in disease therapy, demands a comprehensive overview. In this review, we provide all-inclusive and contemporary gist on PRRs and the applications of their agonizts. We explored the potential of PRR agonizts as vaccine adjuvant. The current review integrates the basic understanding of PRRs and recent findings highlighting emerging trends of the same.

RESULT

Our review highlights that combining multiple PRR agonizts could offer synergistic benefits. This approach might prove advantageous and could potentially enhance vaccine efficacy and reduce the need for excessive immunogens.

CONCLUSION

A comprehensive understanding of PRR subset, agonizts of PRR and their application in vaccine adjuvant. This knowledge will be significant in formulating vaccine approaches.

Targeting KMT5C Suppresses Lung Cancer Progression and Enhances the Efficacy of Immunotherapy

The immune evasion is one major challenge for cancer immunotherapy. Despite considerable advancements in immune checkpoint blockade (ICB) therapies for the advanced non-small cell lung cancer (NSCLC) patients, only a minority of patients receive long-term survival benefit. Here, this work demonstrates that lysine methyltransferase 5C (KMT5C) is a crucial promoter of the NSCLC progression and immune evasion. This work first observes that upregulation of KMT5C in NSCLC correlated with cancer progression and poor patient prognosis. Notably, KMT5C knockdown in NSCLC cells suppress tumor growth and metastasis in mice. Mechanistically, this work demonstrates that KMT5C activated the DNA repair response to inhibit the STING-IRF3 pathway, downstream type I IFN signaling, and CCL5 secretion, leading to the downregulation of CD8+ T cell infiltration and function in NSCLC, ultimately facilitating tumor immune evasion and tumor progression. Importantly, both the pharmacological inhibitor A196 and the genetic inhibition of KMT5C could synergize with anti-PD-1 therapy in the lung cancer mouse model. Clinically, high expression levels of KMT5C in patients with NSCLC are associated with a lower response rate and worse clinical outcomes to ICB therapy. Therefore, these findings identify a previously unknown functional link between KMT5C and tumor immune evasion, and demonstrate that targeting KMT5C may be a potential therapeutic approach for enhancing the efficacy of NSCLC patients to ICB therapy.

Self-promoted tumor-targeting nanomedicine activates STING-driven antitumor immunity via photodynamic DNA damage and PARP inhibition

The activation of antitumor immunity through strategically designed nanomedicine presents a promising approach to overcome the limitations of conventional cancer therapies. In this work, bioinformatic analysis found an abnormal poly(ADP-ribose) polymerase-1 (PARP-1) expression in breast cancer, linked to the cyclic GMP-AMP synthase (cGAS)-stimulator of the interferon gene (STING) pathway and immune suppression. PARP-1 inhibitor screening revealed olaparib (Ola) as a promising candidate, enhancing DNA damage and potentiating the immunotherapeutic response. Consequently, a self-promoted tumor-targeting nanomedicine (designated as PN-Ola) was proposed to activate STING-driven antitumor immunity through photodynamic DNA damage and PARP inhibition. PN-Ola was composed of a programmed death-ligand 1 (PD-L1) targeting amphiphilic peptide-photosensitizer conjugate (C16-K(PpIX)-WHRSYYTWNLNT), which effectively encapsulates Ola. Notably, PN-Ola demonstrated selective accumulation in tumor cells that overexpress PD-L1, while concurrently enhancing PD-L1 expression, thereby establishing a self-promoting mechanism for improved drug accumulation within tumor cells. Meanwhile, the photodynamic therapy (PDT) effects of PN-Ola would result in oxidative DNA damage and subsequent accumulation of DNA fragments. Additionally, the PARP inhibition provided by PN-Ola disrupted the DNA repair pathways in tumor cells, leading to a boosted release of DNA fragments that further stimulated STING-driven antitumor immunity. The synergistic mechanism of PN-Ola effectively activates the immunotherapeutic response by enhancing T cell activation and infiltration, leading to the eradication of metastatic tumors without inducing side effects. This study presents a promising strategy to overcome targeting ligand heterogeneity while activating systemic antitumor immunity for the effective eradication of metastatic tumors.

The bridge-like lipid transport protein VPS13C/PARK23 mediates ER-lysosome contacts following lysosome damage

Based on genetic studies, lysosome dysfunction is thought to play a pathogenetic role in Parkinson's disease. Here we show that VPS13C, a bridge-like lipid-transport protein and a Parkinson's disease gene, is a sensor of lysosome stress or damage. Following lysosome membrane perturbation, VPS13C rapidly relocates from the cytosol to the surface of lysosomes where it tethers their membranes to the ER. This recruitment depends on Rab7 and requires a signal at the damaged lysosome surface that releases an inhibited state of VPS13C, which hinders access of its VAB domain to lysosome-bound Rab7. Although another Parkinson's disease protein, LRRK2, is also recruited to stressed or damaged lysosomes, its recruitment occurs at much later stages and by different mechanisms. Given the role of VPS13 proteins in bulk lipid transport, these findings suggest that lipid delivery to lysosomes by VPS13C is part of an early protective response to lysosome damage.

Adaptations in mitochondrial quality control and interactions with innate immune signaling within skeletal muscle: A narrative review

Skeletal muscle health and function are essential determinants of metabolic health, physical performance, and overall quality of life. The quality of skeletal muscle is heavily dependent on the complex mitochondrial reticulum that contributes toward its unique adaptability. It is now recognized that mitochondrial perturbations can activate various innate immune pathways, such as the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome complex by propagating inflammatory signaling in response to damage-associated molecular patterns (DAMPs). The NLRP3 inflammasome is a multimeric protein complex and is a prominent regulator of innate immunity and cell death by mediating the activation of caspase-1, pro-inflammatory cytokines interleukin-1β and interleukin-18 and pro-pyroptotic protein gasdermin-D. While several studies have begun to demonstrate the relationship between various mitochondrial DAMPs (mtDAMPs) and NLRP3 inflammasome activation, the influence of various metabolic states on the production of these DAMPs and subsequent inflammatory profile remains poorly understood. This narrative review aimed to address this by highlighting the effects of skeletal muscle use and disuse on mitochondrial quality mechanisms including mitochondrial biogenesis, fusion, fission and mitophagy. Secondly, this review summarized the impact of alterations in mitochondrial quality control mechanisms following muscle denervation, aging, and exercise training in relation to NLRP3 inflammasome activation. By consolidating the current body of literature, this work aimed to further the understanding of innate immune signaling within skeletal muscle, which can highlight areas for future research and therapeutic strategies to regulate NLRP3 inflammasome activation during divergent metabolic conditions.

Transposable elements as instructors of the immune system

Transposable elements (TEs) are mobile repetitive nucleic acid sequences that have been incorporated into the genome through spontaneous integration, accounting for almost 50% of human DNA. Even though most TEs are no longer mobile today, studies have demonstrated that they have important roles in different biological processes, such as ageing, embryonic development, and cancer. TEs influence these processes through various mechanisms, including active transposition of TEs contributing to ongoing evolution, transposon transcription generating RNA or protein, and by influencing gene regulation as enhancers. However, how TEs interact with the immune system remains a largely unexplored field. In this Perspective, we describe how TEs might influence different aspects of the immune system, such as innate immune responses, T cell activation and differentiation, and tissue adaptation. Furthermore, TEs can serve as a source of neoantigens for T cells in antitumour immunity. We suggest that TE biology is an important emerging field of immunology and discuss the potential to harness the TE network therapeutically, for example, to improve immunotherapies for cancer and autoimmune and inflammatory diseases.

Neuronal STING-GAT1 signaling maintains paclitaxel-induced neuropathic pain in the spinal cord

ABSTRACT

Stimulator of interferon genes (STING), a pivotal immune regulator, has emerged as a contributor to nociception, yet its role in chronic pains remains still unknown. Here, we demonstrate that STING plays a dual role in normal and neuropathic pain in mature male rodents. Stimulator of interferon genes maintains type I interferon (IFN-I) level restraining pain sensitivity in normal and sham control, while activated STING/interferon regulatory factor 3 (IRF3) signaling increases the expression of gamma-aminobutyric acid (GABA) transporter 1 (GAT1) in the spinal cord (SC), thus, generating paclitaxel (PTX)-induced peripheral neuropathy. Genetic interference of STING (STING-/- mice) attenuated PTX-induced mechanical hypersensitivity with attenuated PTX-induced GAT1 increase, preventing PTX-induced increase in tonic GABAA inhibition of the spinal dorsal horn neurons. Stimulator of interferon genes regulates GAT expression through a TANK-binding kinase 1 (TBK1)-IRF3 signaling pathway, with IRF3 as a crucial transcription factor. Silencing neuronal STING, as opposed to its astrocytic counterpart, effectively restrained the PTX-induced mechanical hypersensitivity and GAT1 increase in the SC. Pharmacological inhibition of STING (H-151) efficiently diminished the TBK1/IRF3/GAT1 signaling pathway to alleviate PTX-induced mechanical hypersensitivity. Our findings show that STING-IRF3 serves a dual role: suppressing physiological nociception through IFN-I and acting as a transcriptional regulator of GAT1, contributing to chemotherapy-induced neuropathic pain.

Trojan Horse-Like Vehicles for CRISPR-Cas Delivery: Engineering Extracellular Vesicles and Virus-Like Particles for Precision Gene Editing in Cystic Fibrosis

The advent of genome editing has kindled the hope to cure previously uncurable, life-threatening genetic diseases. However, whether this promise can be ultimately fulfilled depends on how efficiently gene editing agents can be delivered to therapeutically relevant cells. Over time, viruses have evolved into sophisticated, versatile, and biocompatible nanomachines that can be engineered to shuttle payloads to specific cell types. Despite the advances in safety and selectivity, the long-term expression of gene editing agents sustained by viral vectors remains a cause for concern. Cell-derived vesicles (CDVs) are gaining traction as elegant alternatives. CDVs encompass extracellular vesicles (EVs), a diverse set of intrinsically biocompatible and low-immunogenic membranous nanoparticles, and virus-like particles (VLPs), bioparticles with virus-like scaffold and envelope structures, but devoid of genetic material. Both EVs and VLPs can efficiently deliver ribonucleoprotein cargo to the target cell cytoplasm, ensuring that the editing machinery is only transiently active in the cell and thereby increasing its safety. In this review, we explore the natural diversity of CDVs and their potential as delivery vectors for the clustered regularly interspaced short palindromic repeats (CRISPR) machinery. We illustrate different strategies for the optimization of CDV cargo loading and retargeting, highlighting the versatility and tunability of these vehicles. Nonetheless, the lack of robust and standardized protocols for CDV production, purification, and quality assessment still hinders their widespread adoption to further CRISPR-based therapies as advanced "living drugs." We believe that a collective, multifaceted effort is urgently needed to address these critical issues and unlock the full potential of genome-editing technologies to yield safe, easy-to-manufacture, and pharmacologically well-defined therapies. Finally, we discuss the current clinical landscape of lung-directed gene therapies for cystic fibrosis and explore how CDVs could drive significant breakthroughs in in vivo gene editing for this disease.

Lactylation orchestrates ubiquitin-independent degradation of cGAS and promotes tumor growth

Lactate extensively associates with metabolic reprogramming, signal transduction, and immune modulation. Nevertheless, the regulatory role of lactate in immune sensing of cytosolic DNA remains uncertain. Here, we report that lactate serves as an initiator to facilitate proteasomal degradation of cyclic GMP-AMP synthase (cGAS) independent of ubiquitin, thus repressing the production of interferon and contributing to tumor growth. Mechanistically, lactylation of K21 stimulates cGAS translocation from the nucleus to the proteasome for degradation, which is compromised by phosphorylation of PSMA4 S188 via disrupting its association with cGAS. Concurrently, lactylation of K415 rewires PIK3CB activity and impairs ULK1-driven phosphorylation of PSMA4 S188. Physiologically, lactylation of cGAS sustains tumor growth. Expression of cGAS correlates with the antitumor effect of the LDHA inhibitor FX11. Finally, the lactate-cGAS axis indicates a prognostic outcome of lung adenocarcinoma. Collectively, these findings not only put forth a mechanism of cGAS degradation but also unravel the clinical relevance of cGAS lactylation.

Toxicity mechanism analysis of cGAS-STING-TBK1 signaling pathway small molecule modulator based on network toxicology and molecular docking strategy: quinacrine acetate as an example

Objective

This study aims to investigate the toxicity characteristics and mechanisms of quinacrine acetate, a small molecule modulator of the cGAS-STING-TBK1 signaling pathway, and to establish and validate the application value of network toxicology analysis strategy.

Methods

ProTox and ADMETlab platforms were used to evaluate the toxic effects of quinacrine acetate on human tissues and organs. Potential targets associated with quinacrine acetate toxicity were identified through ChEMBL, STITCH, GeneCards, OMIM, and TD databases. GO and KEGG analyses were employed to elucidate related functions and molecular mechanisms. STRING and Cytoscape software were utilized to identify key hub genes, while molecular docking validation was performed using the CB-Dock2 database. Based on toxicity analysis results, COPD was selected as a disease model, and GEO database was used to analyze the expression characteristics, immune correlation, and drug target value of hub genes in COPD.

Results

ProTox and ADMETlab analyses revealed that quinacrine acetate exhibited significant toxicity to the respiratory system (toxicity level 4, risk coefficient 0.959). Through integrated multi-database analysis, 14 potential targets related to quinacrine acetate-induced respiratory system toxicity were identified. GO and KEGG pathway analyses indicated that quinacrine acetate-induced respiratory toxicity was primarily mediated through metabolic pathways. Network analysis via STRING and Cytoscape identified AKT1, PLA2G4A, and ALOX5 as three core targets. Molecular docking results confirmed strong binding affinity between quinacrine acetate and these core targets. In COPD patients, PLA2G4A and ALOX5 showed significantly upregulated expression, with hub gene ROC curve AUC value reaching 0.829, demonstrating good diagnostic value. Further immune correlation analysis revealed that ALOX5 and PLA2G4A were closely associated with various immune cell expressions and served as targets for multiple drugs including histamine, melittin, and formic acid.

Conclusion

This study demonstrates that quinacrine acetate may influence the progression and risk of respiratory system diseases by regulating metabolic pathways. The findings provide not only a theoretical foundation for understanding the molecular mechanisms of quinacrine acetate-induced respiratory toxicity but also new perspectives and methodological references for evaluating the toxic effects of small molecule compounds in respiratory diseases. Therefore, we demonstrates the practical application value of network toxicology as an efficient predictive tool for identifying potential toxicity targets and pathways, which can guide subsequent experimental validation and provide mechanistic insights that traditional toxicology approaches might miss.

Human papillomavirus E1 proteins inhibit RIG-I/MDA5-MAVS, TLR3-TRIF, cGAS-STING, and JAK-STAT signaling pathways to evade innate antiviral immunity

Human papillomavirus (HPV) is a major etiological agent of both malignant and benign lesions, with high-risk types, such as HPV16 and HPV18, being strongly linked to cervical cancer, while low-risk types like HPV11 are associated with benign conditions. While viral proteins such as E6 and E7 are well-established regulators of immune evasion, the role of E1 in modulating the host antiviral responses remains insufficiently characterized. This study investigates the immunomodulatory functions of HPV16 and HPV11 E1 in suppressing innate antiviral immune signaling pathways. Through a combination of RT-qPCR and luciferase reporter assays, we demonstrate that E1 suppresses the production of interferons and interferon-stimulated genes triggered by viral infections and the activation of RIG-I/MDA5-MAVS, TLR3-TRIF, cGAS-STING, and JAK-STAT pathways. Co-immunoprecipitation assays reveal that E1 interacts directly with key signaling molecules within these pathways. E1 also impairs TBK1 and IRF3 phosphorylation and obstructs the nuclear translocation of IRF3, thereby broadly suppressing IFN responses. Additionally, E1 disrupts the JAK-STAT pathway by binding STAT1, which prevents the assembly and nuclear localization of the ISGF3 complex containing STAT1, STAT2, and IRF9, thereby further diminishing antiviral response. These findings establish E1 as a pivotal regulator of immune evasion and suggest its potential as a novel therapeutic target to enhance antiviral immunity in HPV-associated diseases.

The induction of type I interferonopathy in Trex1-P212fs mice is mediated by activation of the cGAS-STING pathway

The cGAS-STING pathway is crucial for immune tolerance, pathogen resistance, and tumor immunity. Knocking out the cGAS gene can reverse the type I interferonopathy seen in Trex1-/- and Trex1D18N/D18N mice. TREX1, a key DNA-specific exonuclease in mammalian cells, degrades cytoplasmic DNA to prevent excessive immune activation. Mutations in TREX1 are linked to various autoimmune diseases. In prior research, we generated a Trex1-P212fs mouse model associated with systemic lupus erythematosus (SLE) using CRISPR-Cas9 gene editing. This model displays systemic inflammation that mirrors numerous characteristics of both Aicardi-Goutières syndrome (AGS) and SLE in humans. In this study, we found that the TREX1-P212fs mutation resulted in reduced dsDNA enzyme activity. DNA accumulation was present in the cytoplasm of Trex1P212fs/P212fs MEFs. Nonetheless, the role of the cGAS-STING pathway in mediating the disease phenotype in Trex1-P212fs mice associated with SLE has yet to be elucidated. We observed that cGas knockout mitigated systemic inflammation, lymphocyte proliferation, vasculitis, renal disease, and spontaneous T cell activation in Trex1-P212fs mice. Similarly, inhibition of STING with C-176 treatment ameliorated the disease phenotype in Trex1-P212fs mice. These findings elucidate the pathogenesis of TREX1-P212fs-associated type I interferonopathy and offer potential therapeutic targets for their treatment.