Multifaceted functions of STING in human health and disease: from molecular mechanism to targeted strategy

Porcine cGAS-STING signalling induced apoptosis negatively regulates STING downstream IFN response and autophagy via different mechanisms

The innate immune cGAS-STING signalling pathway recognizes double-stranded DNA and induces the interferon (IFN) response, autophagy and apoptosis, exerting a broad antiviral effect. However, the mechanisms and interrelationship between STING induced downstream IFN, autophagy, and apoptosis in livestock have not been fully elucidated. Our previous study defined porcine STING (pSTING) induced IFN, autophagy and apoptosis, and showed that IFN does not affect autophagy and apoptosis, whereas autophagy inhibits both IFN and apoptosis, likely by promoting pSTING degradation. In this study, we further explored the underlying mechanism of pSTING induced apoptosis and the regulation of IFN and autophagy by apoptosis. First, pSTING induces endoplasmic reticulum (ER) stress and mitochondrial damage to activate caspases 9, 3, and 7, which drive intrinsic apoptosis. Second, pSTING triggered apoptosis inhibits the IFN response by activating caspase 7, which cleaves pIRF3 at the species specific D197/D198 site. Third, pSTING activated apoptotic caspases 9, 3, and 7 reduce the expression of ATG proteins, and cleave the ATG5-ATG12L1 complex, effectively inhibiting autophagy. Fourth, knockout of pSTING activated apoptosis heightens the IFN response and autophagy, while suppressing the replication of Herpes Simplex Virus type 1 (HSV-1), Vesicular Stomatitis Virus (VSV) and Pseudorabies Virus (PRV). This study sheds light on the molecular mechanisms of innate immunity in pigs.

STING inhibitors and degraders: Potential therapeutic agents in inflammatory diseases

The regulation of the STING (stimulator of interferon genes) pathway represents a promising target for a range of inflammatory diseases. This review provides an overview of the structure of STING and discusses the mechanisms by which the cyclic GMP-AMP synthase (cGAS)-STING pathway is associated with various autoinflammatory and autoimmune diseases. We explore how targeting STING inhibition or degradation can alleviate excessive inflammatory signaling and improve efficacy. Emerging strategies include inhibiting STING expression by covalently binding compounds or using ligands that target the binding pocket. In addition, selective degradation of STING via the ubiquitin-proteasome system or the lysosomal pathway shows promise. In addition, we explore the implications of modulating the cGAS-STING pathway in the context of various inflammatory diseases. Finally, we summarize the chemical properties of recently developed STING compounds and their potential clinical applications. By comprehensively reviewing the current understanding of the role of STING in inflammation and the therapeutic potential of targeting STING, we aim to identify new avenues of intervention that could improve outcomes for patients with inflammatory diseases. This review highlights the important role of STING in the regulation of inflammation and its potential as a target for innovative therapeutic strategies.

STING contributes to the inflammation and proliferation of Staphylococcus aureus via mitochondrial reactive oxygen species-hypoxic inducible factor 1α axis in epithelial cells

Staphylococcus aureus infection poses a serious threat to the dairy industry and public health safety. The stimulator of interferon gene (STING) signaling pathway has been well established as effective in defending against viral infections. However, the role of STING is controversial during bacterial infections. Herein, we provide an insight into the role of STING during S. aureus infection. Our data revealed that the STING signaling pathway was activated in S. aureus-infected cells. In vitro investigations demonstrated that inhibiting STING reduced inflammation, hypoxia-inducible factor-1 alpha (HIF1α) expression, and mitochondrial reactive oxygen species (mROS) production. Interestingly, blocking HIF1α eliminated the escalation of inflammation associated with STING. Additionally, suppressing mROS production significantly reduced HIF1α expression and inflammation levels, while elevating mROS had the opposite effect. These results indicate that STING promoted inflammation through the mROS-HIF1α pathway. Given that glycolysis is driven by HIF1α, we investigated the role of glycolysis during infection. As expected, STING-elevated inflammation was linked with HIF1α-driven glycolysis. In terms of pathogenesis, STING contributed to S. aureus proliferation within cells and mouse mammary glands. Collectively, our findings demonstrate that STING facilitates infection via the mROS-HIF1α-glycolysis axis, highlighting its potential as a promising anti-inflammatory target.

Unveiling EXOC4/SEC8: a key player in enhancing antiviral immunity by inhibiting the FBXL19-STING1-SQSTM1 signaling axis

As a core aptamer for anti-DNA viral immunity, STING1 (stimulator of interferon response cGAMP interactor 1) is tightly regulated to ensure the proper functioning of the natural antiviral immune response. However, many mechanisms underlying the regulation of STING1 remain largely unknown. In this study, we identify EXOC4/SEC8 (exocyst complex component 4) as a novel positive regulator of DNA virus-triggered type I interferon signaling responses through stabilizing STING1, thereby inhibiting DNA viral replication. Mechanistically, EXOC4 suppresses K27-linked ubiquitination of STING1 at K338, K347, and K370 catalyzed by the E3 ligase FBXL19 (F-box and leucine rich repeat protein 19), thereby preventing ubiquitinated-STING1 from recognition by SQSTM1 (sequestosome 1) for autophagic degradation. Importantly, mice conditionally knocked out for Exoc4/Sec8 are more susceptible to herpes simplex virus type 1 (HSV-1) infection and exhibit more severe lung pathology compared to control mice. This further confirms the important role of EXOC4/SEC8 in antiviral natural immunity. Taken together, our study reveals the importance of EXOC4/SEC8 in promoting STING1-centered antiviral natural immunity and highlights its potential as an anti-DNA viral therapeutic target.

Inflammatory Bowel Disease (IBD)-Associated Colorectal Cancer (CRC): Is cGAS-STING Pathway Targeting the Key to Chemoprevention?

Inflammatory bowel disease (IBD)-associated colorectal cancer (CRC) remains a significant clinical challenge due to its link with chronic inflammation and the inherent limitations of current prevention and surveillance strategies. The cGAS-STING pathway has emerged as a key player in the immune regulation of inflammation-driven carcinogenesis, demonstrating both protective and pathogenic roles. This review examines the contrasting roles of the cGAS-STING signaling pathway in intestinal inflammation and colitis-associated cancer (CAC), emphasizing its promise as a target for cancer prevention strategies. Evidence suggests that modulating this pathway could preserve epithelial integrity, limit chronic inflammation, and bolster anti-tumor immunity. Despite advancements in therapies like mesalazine and surveillance colonoscopy programs, gaps in efficacy remain, particularly for Crohn's disease and high-risk populations. Future research should focus on integrating cGAS-STING-targeted approaches with existing modalities to provide personalized and less invasive strategies for CAC prevention. By harnessing this pathway's therapeutic potential, a paradigm shift in managing IBD-associated CRC may be achieved, addressing the challenges of long-term disease surveillance and prevention.

cGAS-STING targeting offers a novel therapeutic paradigm in cardiovascular diseases

Cyclic GMP/AMP (cGAMP) synthase (cGAS), along with the endoplasmic reticulum (ER)-associated stimulator of interferon genes (STING), are crucial elements of the type 1 interferon response. cGAS senses microbial DNA and self-DNA, labeling cGAS-STING as a crucial mechanism in autoimmunity, sterile inflammatory responses, and cellular senescence. However, chronic and aberrant activation of the cGAS/STING axis results in inflammatory and autoimmune diseases. cGAS-STING has emerged as a vital mechanism driving inflammation-related diseases, including cardiovascular diseases (CVDs). Insights into the biology of the cGAS-STING pathway have enabled the discovery of small-molecule agents which have the potential to inhibit the cGAS-STING axis in many human diseases. In this review, we first outline the principal components of the cGAS-STING signaling cascade. From such we discuss recent research that highlights general mechanisms by which cGAS-STING contributes to CVDs. Then, we summarize a list of bioactive small-molecule compounds which modulate the cGAS-STING axis, reviewing their potential clinical applications. Finally, we discuss key limitations of this new proposed therapeutic approach and provide possible techniques to overcome them.These review highlights a novel groundbreaking therapeutic possibilities through targeting cGAS-STING in CVDs.

Icariin alleviates cognitive dysfunction by reducing neuroinflammation via the cGAS-STING pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedium brevicornu Maxim, a Chinese herbal medicine, is known for its efficacy in nourishing the kidneys. Icariin (ICA), the primary active ingredient in Epimedium brevicornu Maxim., possesses multiple pharmacological properties, yet its impact on Alzheimer's disease (AD) warrants further exploration.

AIM OF THE STUDY

Study aims to explore the inhibitory impact of ICA on neuroinflammation in AD via the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway.

MATERIALS AND METHODS

SPF-grade male ICR mice were used to establish an AD model by lateral ventricle injection of Aβ1-42. Behavioral, pathological assessments, as well as immunofluorescence staining, molecular docking, and Western blot analyses, were conducted to evaluate the effects of ICA treatment on memory function, neuronal damage, neuroinflammation, and the cGAS- STING pathway in mice.

RESULTS

ICA significantly improved memory impairment, alleviated neuronal damage and apoptosis, and suppressed neuroinflammation in AD mice. Additionally, ICA inhibited microglial hyperactivation, promoting the transition from the M1 to the M2 phenotype. It specifically inhibited the activation of the cGAS-STING pathway and down-regulated the expression of cGAS, STING, p-TBK1/TBK1, p-IRF3/IRF3 and p-NF-κB/NF-κB. Furthermore, molecular docking revealed that the binding energy between ICA and cGAS was -7.07 kcal/mol, indicating a stable interaction. Further validation using the cGAS-selective small molecule inhibitor RU.521 confirmed the protective effects of ICA against cGAS-STING signaling on microglial transformation and neuroinflammation.

CONCLUSION

ICA exhibits therapeutic potential in AD by inhibiting microglial transformation and neuroinflammation through the cGAS-STING pathway, positioning it as a candidate drug for AD treatment targeting this pathway.

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.

Inflammatory signaling pathways in pancreatic β-cell: New insights into type 2 diabetes pathogenesis

Type 2 diabetes (T2D) is a complex metabolic disorder with a growing global prevalence, and there is a linking between inflammation in pancreatic β-cell and impaired glucose homeostasis which has emerged as a key player in the pathogenesis of T2D. Recent advances in research have provided new insights into various inflammatory signaling cascades in β-cell among which we focus on Toll-like Receptor 4 (TLR4), Nuclear Factor kappa B (NF-κB), Janus Kinase-Signal Transducer and Activator of Transcription (JAK/STAT), Platelet-Derived Growth Factor Receptor α (PDGFR-α), Stimulator of Interferon Genes (STING), and the death receptor TMEM219. TLR4 activation by pathogen- or damage-associated molecular patterns initiates NF-κB and mitogen-activated protein kinase (MAPK) cascades, promoting pro-inflammatory cytokine release and β-cell apoptosis. NF-κB acts as a central hub, integrating metabolic stress signals (e.g., glucolipotoxicity, ER stress) and amplifying inflammatory responses through crosstalk with JAK/STAT and STING pathways. Meanwhile, JAK/STAT signaling exhibits dual roles in β-cell survival and inflammation, influenced by cytokine milieu and feedback regulation. PDGFR-α, traditionally linked to β-cell proliferation, paradoxically contributes to pathological hyperplasia in obesity, while STING activation by cytosolic DNA triggers β-cell senescence and ferroptosis via IRF3/NF-κB. In this review, we synthesize recent advancements of these inflammatory signaling pathways in β-cells, and current therapeutic strategies targeting TLR4/NF-κB inhibitors, JAK/STAT modulators, STING antagonists, and the death receptor TMEM219 are discussed, alongside challenges in pathway specificity and clinical translation. Understanding these inflammatory signaling pathways and their interactions in pancreatic β-cell is essential for the development of novel therapeutic strategies to prevent or treat T2D.

Regulation and function of PI4P at the Golgi complex

Fifty years after Bob Michell's visionary prediction, phosphatidylinositol 4-phosphate (PI4P) has emerged as a central regulator of Golgi function, influencing membrane trafficking, lipid metabolism, and signaling. PI4P homeostasis is tightly controlled by phosphatidylinositol 4-kinases (PI4Ks), phosphatidylinositol transfer proteins (PITPs), and the phosphatase SAC1, ensuring precise regulation across Golgi subdomains. Beyond its classical role in vesicular transport, PI4P orchestrates lipid exchange at membrane contact sites, enabling dynamic Golgi maturation and functional specialization. The interplay between PI4P, lipid transfer proteins, and Golgi adaptors underlies cargo sorting, glycosylation, and organelle architecture. Emerging evidence also highlights PI4P's role in oncogenesis and cellular signaling, positioning the Golgi as a critical hub beyond secretion. Yet, key questions remain regarding PI4P compartmentalization and its broader physiological impact. This review revisits PI4P's essential functions, integrating historical insights with recent discoveries to illuminate its pivotal role in Golgi biology and beyond.

Specific Activation of the STING Pathway by Engineering Piezoelectric Hydrogel Microspheres for Boosting Implant Infection Immunotherapy

Implant-associated infections (IAIs) represent the primary cause of prosthetic implant failure. Bacterial biofilms hinder the host's immune response, creating ″immune cold zones.″ ″Immune activation therapy″ presents a viable strategy for addressing IAIs. Nonetheless, focusing solely on regulating innate immune cells like macrophages falls short for effective antibiofilm outcomes. Herein, a multifunctional antimicrobial system capable of utilizing ultrasound (US)-induced tandem catalysis and activating innate and adaptive antimicrobial immune responses is proposed. The integration of piezoelectric barium titanate with STING plasmids both encapsulated in liposomes and embedded in hydrogel microspheres. US activation generates reactive oxygen species, effectively destroying biofilms and subsequently exposing bacterial antigens. US can destroy liposomes and release STING plasmids, thereby activating the cGAS-STING pathway and triggering antimicrobial innate immunity. Additionally, it can also induce DC maturation, enhance bacterial antigen presentation, alleviate immunosuppression, and boost adaptive immunity. This study proposes a promising strategy combining antimicrobial and immunotherapy, offering an alternative to antibiotics for IAI treatment.

Discovery of Potent STING Inhibitors Bearing a Difluorobenzodioxol Structural Motif as Potent Anti-Inflammatory Agents

Given the critical role of STING in autoimmune and inflammatory disorders, the development of targeted small-molecule inhibitors has been a promising strategy for the treatment of these diseases. Nevertheless, the currently reported STING inhibitors suffer from limited structural diversity, species sensitivity, and poor activity; therefore, none are suitable for clinical investigation. Herein, we performed a structural modification campaign on the tool compound 6 (H-151) based on its potential metabolic hotspots. Compound 66, bearing a difluorobenzodioxol moiety, was identified as one of the most potent STING inhibitors with IC50 values of 116 and 96.3 nM for h- and m-STING, respectively. This compound exhibited a notable enhancement in metabolic properties, especially in terms of metabolic stability. A mechanism study verified that 66 engaged with STING in a covalent manner akin to that of 6. In both the cisplatin-induced acute kidney injury and TREX1 D18N mouse models, 66 significantly alleviated tissue injury and inflammation.

Carvedilol sensitizes chemotherapy by targeting STING to boost anti-tumor immunity

The stimulator of interferon genes (STING)-mediated type I interferon (IFN) response is critical for mounting anti-tumor immunity and sensitizing chemotherapy by remodeling the tumor immune microenvironment. However, no clinically available drugs have been applied for STING activation. Based on high-throughput screening of small-molecule microarrays, we found that carvedilol, an adrenergic receptor blocker used to treat essential hypertension and symptomatic heart failure, is a STING activator. Mechanistically, carvedilol interacts with STING at threonine 263 and enhances its dimerization. Importantly, carvedilol enhances the therapeutic effect of etoposide in both the allografted tumor model and patient-derived tumor-like cell clusters (PTCs) by promoting etoposide-induced STING activation. Our findings identify carvedilol as a STING activator and provide a theoretical basis for combining carvedilol and etoposide in cancer therapy.

Oligomerization of STING and Chemical Regulatory Strategies

Stimulator of interferon genes (STING) plays a crucial role in innate immunity. Upon the recognition of cytosolic dsDNA, STING undergoes several structural changes, with oligomerization playing a key role in initiating a cascade of immune responses. Therefore, controlling the STING pathway by manipulating STING oligomerization is a practical strategy. This review focuses on the detailed mechanism of STING oligomerization, highlighting its decisive role. It also describes oligomerization-based strategies to regulate STING protein, such as the use of small-molecule agonists and biomacromolecules, highlighting their interaction modes and potential therapeutic applications. This knowledge may lead to the development of innovative approaches for treating cancer and immune disorders.

A non-canonical cGAS-STING pathway drives cellular and organismal aging

Accumulation of cytosolic DNA has emerged as a hallmark of aging, inducing sterile inflammation. STING (Stimulator of Interferon Genes) protein translates the sensing of cytosolic DNA by cGAS (cyclic-GMP-AMP synthase) into an inflammatory response. However, the molecular mechanisms whereby cytosolic DNA-induced cGAS-STING pathway leads to aging remain poorly understood. We show that STING does not follow the canonical pathway of activation in human fibroblasts passaged (aging) in culture, senescent fibroblasts, or progeria fibroblasts (from Hutchinson Gilford Progeria Syndrome patients). Despite cytosolic DNA buildup, features of the canonical cGAS-STING pathway like increased cGAMP production, STING phosphorylation, and STING trafficking to perinuclear compartment are not observed in progeria/senescent/aging fibroblasts. Instead, STING localizes at endoplasmic reticulum, nuclear envelope, and chromatin. Despite the non-conventional STING behavior, aging/senescent/progeria cells activate inflammatory programs such as the senescence-associated secretory phenotype (SASP) and the interferon (IFN) response, in a cGAS and STING-dependent manner, revealing a non-canonical pathway in aging. Importantly, progeria/aging/senescent cells are hindered in their ability to activate the canonical cGAS-STING pathway with synthetic DNA, compared to young cells. This deficiency is rescued by activating vitamin D receptor signaling, unveiling new mechanisms regulating the cGAS-STING pathway in aging. Significantly, in HGPS, inhibition of the non-canonical cGAS-STING pathway ameliorates cellular hallmarks of aging, reduces tissue degeneration, and extends the lifespan of progeria mice. Our study reveals that a new feature of aging is the progressively reduced ability to activate the canonical cGAS-STING pathway in response to cytosolic DNA, triggering instead a non-canonical pathway that drives senescence/aging phenotypes.

Significance Statement

Our study provides novel insights into the mechanisms driving sterile inflammation in aging and progeria. We reveal a previously unrecognized characteristic of aging cells: the progressive loss of ability to activate the canonical response to foreign or self-DNA at the cytoplasm. Instead, aging, senescent, and progeria cells activate inflammatory programs via a non-conventional pathway driven by cGAS and the adaptor protein STING. Importantly, pharmacological inhibition of the non-canonical cGAS-STING pathway ameliorates cellular, tissue and organismal decline in a devastating accelerated aging disease (Hutchinson Gilford Progeria Syndrome), highlighting it as a promising therapeutic target for age-related pathologies.

Protective effects of berberine on MASLD: regulation of glucose and lipid metabolism through PI3K/Akt and STING pathways

This study is aimed at exploring the therapeutic potential of berberine (BBR) in mitigating metabolic dysfunction-associated steatotic liver disease (MASLD) and at elucidating its mechanisms of action, with a focus on the modulation of glucose and lipid metabolism via the PI3K/Akt and STING signaling pathways. Male C57BL/6 J mice were fed a high-fat diet (HFD) to induce MASLD and subsequently treated with BBR or metformin. HepG2 cells were cultured in vitro, and palmitic acid (PA) was used to construct the cell model. Comprehensive analyses, including network pharmacology, transcriptome sequencing, and Western blotting, were conducted to identify critical pathways and molecular targets. Biochemical, histological, and molecular assays were performed to evaluate metabolic and inflammatory responses. BBR significantly attenuated HFD-induced hepatic steatosis, inflammation, and glucose intolerance. It effectively reduced lipid accumulation, enhanced insulin sensitivity, and modulated the expression of genes involved in lipid metabolism. Network pharmacology and transcriptome analysis highlighted the involvement of the PI3K/Akt and STING pathways. BBR activated PI3K/Akt signaling while suppressing the STING pathway, thereby reducing lipid accumulation in both in vivo and in vitro models. The inhibition of AKT negated the beneficial effects of BBR, underscoring the pivotal role of PI3K/Akt in regulating STING signaling. BBR ameliorates MASLD by activating the PI3K/Akt pathway and inhibiting the STING pathway, leading to improved glucose and lipid metabolism. These findings position BBR as a promising therapeutic candidate for the treatment of MASLD.

Targeting tumor monocyte-intrinsic PD-L1 by rewiring STING signaling and enhancing STING agonist therapy

STING is an important DNA sensing machinery in initiating immune response, yet therapies targeting STING have shown poor outcomes in clinical trials. Here, we reveal that STING signaling induces PD-L1hi tumor monocytes (Tu.Mons) that dominate the resistance against STING agonist therapy. Cell-intrinsic PD-L1, induced by the STING-IRF3-IFN-I axis, is identified as the driving factor for protumoral PD-L1hi Tu.Mons. Notably, TLR2-activated Tu.Mons resist STING-induced upregulation of cell-intrinsic PD-L1 and the associated protumoral functions. Mechanistically, TLR2 stimulation remodels STING signaling by facilitating STING and TRAF6 interaction, which suppresses the IRF3-IFN-I response and enhances NF-κB activation. Moreover, we demonstrate that combining STING agonists with TLR2 agonist pretreatment significantly improves antitumor efficacy in murine syngeneic and humanized models. Our findings uncover a protumoral aspect of STING activation mediated by cell-intrinsic PD-L1 and propose a promising strategy to boost antitumor immunity by fine-tuning STING signaling outputs.

Multidimensional applications of prussian blue-based nanoparticles in cancer immunotherapy

Immunotherapy holds notable progress in the treatment of cancer. However, the clinical therapeutic effect remains a significant challenge due to immune-related side effects, poor immunogenicity, and immunosuppressive microenvironment. Nanoparticles have emerged as a revolutionary tool to surmount these obstacles and amplify the potency of immunotherapeutic agents. Prussian blue nanoparticles (PBNPs) exhibit multi-dimensional immune function in cancer immunotherapy, including acting as a nanocarrier to deliver immunotherapeutic agents, as a photothermal agent to improve the efficacy of immunotherapy through photothermal therapy, as a nanozyme to regulate tumor microenvironment, and as an iron donor to induce immune events related to ferroptosis and tumor-associated macrophages polarization. This review focuses on the advances and applications of PBNPs in cancer immunotherapy. First, the biomedical functions of PBNPs are introduced. Then, based on the immune function of PBNPs, we systematically reviewed the multidimensional application of PBNPs in cancer immunotherapy. Finally, the challenges and future developments of PBNPs-based cancer immunotherapy are highlighted.

Facile integration of a binary nano-prodrug with αPD-L1 as a translatable technology for potent immunotherapy of TNBC

Immune checkpoint blockers (ICBs)-based immunotherapy is a favorable approach for efficient triple-negative breast cancer (TNBC) treatment. However, the therapeutic efficacy of ICBs is greatly compromised by immunosuppressive tumor microenvironments (TMEs) and low expression levels of programmed cell death ligand-1 (PD-L1). Herein, we constructed an amphiphilic prodrug by linking a hydrophobic STING agonist, MSA-2 and a hydrophilic chemotherapeutic drug, gemcitabine (GEM) via an ester bond, which can self-assemble into GEM-MSA-2 (G-M) nanoparticles (NPs) with a tumor growth inhibition (TGI) value of 87.1 % in a murine 4T1 transplantation tumor model. Notably, the immunogenic cell death (ICD)-triggering effect of GEM together with the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway activation properties of MSA-2 enables efficient infiltration of non-exhausting T cells and repolarization of macrophages from M2 to M1 types in the tumor microenvironment for transforming a cold tumor to a hot one. Most importantly, G-M NPs treatment increases the PD-L1 expression levels, thus providing a unique opportunity for further integration with anti-PD-L1 monoclonal antibody (αPD-L1) for eliciting stronger immunity that ultimately leads to a TGI value of 98.0 % in the primary tumor and significantly protects against distal and disseminated tumor rechallenge. Overall, this study presents a minimalist nano-prodrug combined with αPD-L1 as a simple yet robust translatable nanotechnology for potent chemo-immunotherapy of TNBC. STATEMENT OF SIGNIFICANCE: Enhancing the therapeutic efficacy of αPD-L1 for tumor immunotherapy via a translatable technology remains a challenge. We report herein facile integration of a binary nano-prodrug with αPD-L1 for potent immunotherapy of TNBC. An amphiphilic prodrug is constructed by linking a hydrophobic STING agonist, MSA-2 and a hydrophilic chemotherapeutic drug, gemcitabine (GEM) via an ester bond. The resulting self-assembled GEM-MSA-2 (G-M) nanoparticles (NPs) show a tumor growth inhibition (TGI) value of 87.1 % in a murine 4T1 transplantation tumor model. Besides the induced immunogenic cell death (ICD) and activated cGAS-STING pathway, G-M NPs increase the PD-L1 expression levels, providing a unique opportunity for further integration with αPD-L1 to elicit stronger immunity that ultimately leads to a TGI value of 98.0 % in the primary tumor and significantly protects against distal and disseminated tumor rechallenge.

MAVS: The next STING in cancers and other diseases

The mitochondrial antiviral signaling protein (MAVS) is a pivotal adaptor in the antiviral innate immune signaling pathway and plays a crucial role in the activation of antiviral defences. This comprehensive review delves into the multifaceted functions of MAVS, spanning from its integral role in the RIG-I-like receptor (RLR) pathway to its emerging roles in tumor biology and autoimmune diseases. We discuss the structural and functional aspects of MAVS, its activation mechanisms, and the intricate regulatory networks that govern its activity. The potential of MAVS as a therapeutic target has been explored, highlighting its promise in personalized cancer therapy and developing combination treatment strategies. Additionally, we compare it with the STING signaling pathway and discuss the synergistic potential of targeting both pathways in immunotherapy. Our review underscores the importance of MAVS in maintaining immune homeostasis and its implications for a broad spectrum of diseases, offering new avenues for therapeutic intervention.

cGAS-STING targeting offers novel therapeutic opportunities in neurological diseases

Cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) (cGAMP) synthase (cGAS) is a cytosolic DNA sensor that produces the secondary messenger cGAMP. cGAMP activates the endoplasmic reticulum-associated adaptor stimulator of interferon genes (STING) and activates the innate immune system to produce a type I interferon response. Besides sensing microbial DNA, cGAS can also be activated by self-DNA or endogenous DNA, including that derived from genotoxic extranuclear chromatin and mitochondrially released DNA, indicating that cGAS-STING is an important mechanism in sterile inflammatory responses, autoimmunity, and cellular senescence. However, aberrant activation of the cGAS-STING pathway results in inflammatory and autoimmune diseases. cGAS-STING has emerged as a vital mechanism driving the pathogenesis of inflammation, implicating cGAS-STING signaling in neurological diseases. In this review, we first outline the principal elements of the cGAS-STING signaling cascade, summarizing recent research highlighting how cGAS-STING activation contributes to the pathogenesis of neurological diseases, including various autoimmune, autoinflammatory, and neurodegenerative diseases. Next, we outline selective small-molecule modulators that function as cGAS-STING inhibitors and summarize their mechanisms for treating multiple neurological diseases. Finally, we discuss key limitations of the current therapeutic paradigm and generate possible strategies to overcome them.

NLRP3 Inflammasome Targeting Offers a Novel Therapeutic Paradigm for Sepsis-Induced Myocardial Injury

Cardiac or myocardial dysfunction induced by sepsis, known as sepsis-induced cardiomyopathy or sepsis-induced myocardial injury (SIMI), is a common complication of sepsis and is associated with poor outcomes. However, the pathogenesis and molecular mechanisms underlying SIMI remain poorly understood, requiring further investigations. Emerging evidence has shown that NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to SIMI. Compounds that inhibit NLRP3-associated pyroptosis may exert therapeutic effects against SIMI. In this review, we first outlined the principal elements of the NLRP3 signaling cascade and summarized the recent studies highlighting how NLRP3 activation contributes to the pathogenesis of SIMI. We outlined selective small-molecule modulators that function as NLRP3 inhibitors and delineated their mechanisms of action to attenuate SIMI. Finally, we discuss the major limitations of the current therapeutic paradigm and propose possible strategies to overcome them. This review highlights the pharmacological inhibition of SIMI as a promising therapeutic strategy.

Profile of STING agonist and inhibitor research: a bibliometric analysis

Background

STING is a core signaling hub molecule in the innate immune system, involved in various diseases, including infectious diseases, autoimmune diseases, tumors, aging, organ fibrosis, and neurodegenerative diseases. Its activation has shown great potential in anti-tumor and anti-infective therapies, with STING agonists emerging as a promising approach in cancer immunotherapy in recent years. This study identifies research trends and potential directions in the field by collecting and analyzing relevant literature.

Methods

A total of 527 publications regarding STING agonists and 107 about inhibitors were retrieved from the WOS Core Collection database. Bibliometric information was extracted with CiteSpace and VOSviewer software for visualization.

Results

It shows that research on both STING agonists and inhibitors is burgeoning rapidly. The United States and China are leading contributors in this field. Application of STING agonists primarily focuses on cancer immunotherapy, while STING inhibitors target inflammation, particularly neuroinflammation and acute lung injury.

Conclusion

Current research emphasizes optimizing STING agonists for permeability, efficacy, and safety, with nanotechnology and lipid nanoparticles being prominent delivery techniques. Future research is expected to focus on drug development and clinical applications. This comprehensive bibliometric analysis provides clinical insights and a guide for further investigation to STING agonist/inhibitor.

AlbiCDN: albumin-binding amphiphilic STING agonists augment the immune activity for cancer immunotherapy

The stimulator of interferon genes (STING) has been an attractive target in cancer immunotherapy. However, natural ligand cyclic dinucleotides (CDNs) and CDN derivatives have demonstrated limited efficacy in clinical trials. This limitation stems from the inherent structure of CDNs, which leads to enzymatic degradation, poor cell internalisation, rapid clearance from the tumour microenvironment, and dose-limiting toxicity. In this study, we developed an amphipathic STING agonist, termed albumin-binding CDNs (AlbiCDNs), to enhance the efficacy of c-di-GMP (CDG) via a lipid-conjugated strategy. The lipid provided a platform for albumin hitchhiking, which facilitated the cytoplasmic delivery of CDG without the use of any exogenous components. In addition, incorporating a stimuli-responsive lipid motif further enhanced the cellular release of CDG. Our results indicated that CDG-1C14, an AlbiCDN, efficiently stimulated the maturation and activation of antigen-presenting cells through STING activation. Furthermore, CDG-1C14 exhibited a significant inhibitory effect on the tumour therapeutic model. Therefore, AlbiCDN is a potent platform for cancer immunotherapy that can expedite clinical translation.

cGAS-STING targeting offers therapy choice in lung diseases

Cyclic GMP/AMP (cGAMP) synthase (cGAS), along with the endoplasmic reticulum (ER)-associated stimulator of interferon genes (STING), are crucial elements of the type 1 interferon response. cGAS senses microbial DNA and self-DNA, labeling cGAS-STING as a crucial mechanism in autoimmunity, sterile inflammatory responses, and cellular senescence. However, chronic and aberrant activation of the cGAS-STING axis results in inflammatory and autoimmune diseases. cGAS-STING has emerged as a vital mechanism driving inflammation-related diseases, including lung diseases. Insights into the biology of the cGAS-STING pathway have enabled the discovery of small-molecule agents which have the potential to inhibit the cGAS-STING axis in lung diseases. In this review, we first outline the principal components of the cGAS-STING signaling cascade. Then, we discuss recent research that highlights general mechanisms by which cGAS-STING contributes to lung diseases. Then, we focus on summarizing a list of bioactive small-molecule compounds which inhibit the cGAS-STING pathway, reviewing their potential mechanisms.These review highlights a novel groundbreaking therapeutic possibilities through targeting cGAS-STING in lung diseases.

Targeting ferroptosis offers therapy choice in sepsis-associated acute lung injury

Sepsis-associated acute lung injury (SALI) is a common complication of sepsis, consisting of a dysfunctional host response to infection-mediated heterogenous complexes. SALI is reported in up to 50 % of patients with sepsis and causes poor outcomes. Despite high incidence, there is a lack of understanding in its pathogenesis and optimal treatment. A better understanding of the molecular mechanisms underlying SALI may help produce better therapeutics. The effects of altered cell-death mechanisms, such as non-apoptotic regulated cell death (RCD) (i.e., ferroptosis), on the development of SALI are beginning to be discovered, while targeting ferroptosis as a meaningful target in SALI is increasingly being recognized. Here, we outline how a susceptible lung alveoli may develop SALI. Then we discuss the general mechanisms underlying ferroptosis, and how it contributes to SALI. We then outline the chemical structures of the emerging agents or compounds that can protect against SALI by inhibiting ferroptosis, summarizing their potential pharmacological effects. Finally, we highlight key limitations and possible strategies to overcome them. This review suggests that a detailed mechanistic and biological understanding of ferroptosis can foster the development of pharmacological antagonists in the treatment of SALI.

A central role of stimulator of interferon genes' adaptor protein in defensive immune response

Cytotoxic DNAs, methylation, histones and histones binding proteins are speculated to induce DNA sensors. Under stressed condition, the antigenic patterns, PAMPs and DAMPs, trigger the hyperactive innate response through DNA, DNA-RNA hybrids, oligonucleotides, histones and mtDNA to initiate cGAMP-STING-IFN I cascade. HSV -1&2, HIV, Varicella- Zoster virus, Polyomavirus, Cytomegalovirus, and KSHV negatively regulate the STING-MAVS-TBK-1/1KKE pathway. Implications in STING-PKR-ER regulation often run into causing senescence and organ fibrosis. Post-translational modifications such as, phosphorylation, ubiquitination, SUMOylation, hydrolysis etc. downstream the processing of cGAS-STING that determine the fate of disease prognosis. Self-DNA under normal circumstances is removed through DNase III action; however, its deficiency is the great cause of RA diseases. Regular STING activation in chronic diseases could lead to exacerbate the neurodegenerative disorders due to constant mtDNA leakage. 2' 3' cGAMP or CDN or its associates are being explored as STING agonist therapeutics to treat solid/metastatic tumors to help infiltrate the immune cells, cytokines and chemokines to regulate the protective response. Liposomes, polymer nanoparticles, and cell-derived nanoparticles are also meant to increase the drug efficiency and stability for desired immune response to enhance the IFN I production. This review highlights the implications of cGAMP-STING- IFN I cascade and related pathways involved in the disease prognosis, therapeutics and considering the gaps on different aspects to utilize its greater potential in disease control.

Macrophage STING signaling promotes fibrosis in benign airway stenosis via an IL6-STAT3 pathway

Acute and chronic inflammation are important pathologies of benign airway stenosis (BAS) fibrosis, which is a frequent complication of critically ill patients. cGAS-STING signalling has an important role in inflammation and fibrosis, yet the function of STING in BAS remains unclear. Here we demonstrate using scRNA sequencing that cGAS‒STING signalling is involved in BAS, which is accompanied by increased dsDNA, expression and activation of STING. STING inhibition or deficiency effectively alleviates tracheal fibrosis of BAS mice by decreasing both acute and chronic inflammation. Macrophage depletion also effectively ameliorates BAS. Mechanistically, dsDNA from damaged epithelial cells activates the cGAS-STING pathway of macrophages and induces IL-6 to activate STAT3 and promote fibrosis. In summary, the present results suggest that cGAS-STING signalling induces acute inflammation and amplifies the chronic inflammation and tracheal fibrosis associated with benign airway stenosis, highlighting the mechanism and potential drug target of BAS.

Regulation of STING G-quadruplex for rescuing cellular senescence and Aβ phagocytic capacity of microglia

Alzheimer's disease (AD), the most common form of dementia, affects millions of people worldwide and its cause is very complicated. Besides the classical amyloid cascade hypothesis, oxidative stress, metal ion imbalance, cellular senescence and neuroinflammation are also considered crucial triggers of AD. Therefore, therapeutic strategies other than inhibiting Aβ deposition are very promising. As a crucial innate immune pathway, the abnormal activation of the cGAS-STING pathway in AD has attracted much attention and become a promising target for AD treatment. Here, we identify a highly conserved and stable G-quadruplex (G4) in the STING promoter region, and further verify its function in transcriptional inhibition of STING by using CRISPR technology to precisely target STING G4. Intriguingly, down-regulation of STING expression can alleviate cellular senescence and restore the Aβ phagocytic capacity of microglia. Our results highlight the compelling therapeutic potential of STING promoter G4 for regulation of the abnormal activation of the cGAS-STING pathway in AD. Different from the existing therapeutic strategies for AD, this work provides an alternative way of targeting the functional gene secondary structure, such as the STING promoter region, which may promote the design and synthesis of drug candidates for AD.

Stimulator of Interferon Genes Signal in Lung Cancer Regulates Differentiation of Myeloid-Derived Suppressor Cells in the Tumor Microenvironment Via the Interferon Regulatory Factor 3/NF-κB Pathway

Background: This study was designed to explore the action mechanism of stimulator of interferon genes (STING) on the differentiation of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment of lung cancer. Methods: Bioinformatics analysis yielded a potential pathway for STING to regulate MDSC differentiation, the interferon regulatory factor 3 (IRF3)/NF-κB axis. The transfection efficiency of STING overexpression plasmid and small interfering RNA against IRF3 (siIRF3) was examined by quantitative real-time polymerase chain reaction (qRT-PCR). After transfection, A9 cells were co-cultured with extracted bone marrow cells (BMCs). MDSC differentiation, protein expression of the IRF3/NF-κB pathway, and changes in nuclear translocation of NF-κB were analyzed by flow cytometry, Western blot, and immunofluorescence staining experiments. A transplanted tumor mouse model was used for in vivo experiments. After cyclic diadenyl monophosphate (CDA; STING agonist) treatment, changes in MDSC differentiation and protein expression of the IRF3/NF-κB axis in transplanted tumors were verified by immunohistochemical staining, qRT-PCR, and Western blot. Results: Coculture of A9 cells and BMCs promoted MDSC differentiation, inhibited activation of IRF3/NF-κB signal in A9 cells, and boosted nuclear translocation of NF-κB. However, after the upregulation of STING, IRF3/NF-κB signal was activated, while MDSC differentiation and nuclear translocation of NF-κB were inhibited. SiIRF3 reversed the effects of STING overexpression. In vivo, CDA dampened MDSC differentiation and promoted protein expression of the IRF3/NF-κB axis. Conclusion: STING signal in lung cancer cells inhibits MDSC differentiation through activation of the IRF3/NF-κB pathway.

Environmental Low-Dose Radiation Activates Th1 Immunity through the Mitochondria-STING Pathway

The presence of low-dose radiation (LDR) in the environment has become more prevalent. However, the effect of LDR exposure on the immune system remains elusive. Here, we interestingly found that LDR specifically elevated the percentage of CD4+IFNγ+ Th1 splenocytes, both in vitro and in vivo, without affecting the percentage of CD8+IFNγ+ Tc1 cells and regulatory T cells. A similar phenomenon was found in T cells from peripheral blood. Mechanistically, we found that LDR can induce mitochondrial damage, which stimulated the STING signaling pathway, leading to the enhanced expression of T-bet, the master transcriptional factor of Th1-cell differentiation. The specific STING signal inhibitor can abrogate the effect of LDR on Th1 differentiation, confirming the central role of the STING pathway. To further validate the immunoregulatory role of LDR, we exposed mice with whole body LDR and evaluated if LDR could protect mice against triple-negative breast cancer through enhanced antitumor immunity. As expected, LDR significantly delayed tumor development and promoted cell death. Meanwhile, LDR resulted in increased tumor-infiltrating Th1 cells, while the proportion of Tc1 and Treg cells remained unchanged. Furthermore, the infiltration of antitumor macrophages was also increased. In summary, we revealed that environmental LDR could specifically regulate Th1 T-cell activities, providing critical information for the potential application of LDR in both clinical and nonclinical settings.

Apolipoprotein-L Functions in Membrane Remodeling

The mammalian Apolipoprotein-L families (APOLs) contain several isoforms of membrane-interacting proteins, some of which are involved in the control of membrane dynamics (traffic, fission and fusion). Specifically, human APOL1 and APOL3 appear to control membrane remodeling linked to pathogen infection. Through its association with Non-Muscular Myosin-2A (NM2A), APOL1 controls Golgi-derived trafficking of vesicles carrying the lipid scramblase Autophagy-9A (ATG9A). These vesicles deliver APOL3 together with phosphatidylinositol-4-kinase-B (PI4KB) and activated Stimulator of Interferon Genes (STING) to mitochondrion-endoplasmic reticulum (ER) contact sites (MERCSs) for the induction and completion of mitophagy and apoptosis. Through direct interactions with PI4KB and PI4KB activity controllers (Neuronal Calcium Sensor-1, or NCS1, Calneuron-1, or CALN1, and ADP-Ribosylation Factor-1, or ARF1), APOL3 controls PI(4)P synthesis. PI(4)P is required for different processes linked to infection-induced inflammation: (i) STING activation at the Golgi and subsequent lysosomal degradation for inflammation termination; (ii) mitochondrion fission at MERCSs for induction of mitophagy and apoptosis; and (iii) phagolysosome formation for antigen processing. In addition, APOL3 governs mitophagosome fusion with endolysosomes for mitophagy completion, and the APOL3-like murine APOL7C is involved in phagosome permeabilization linked to antigen cross-presentation in dendritic cells. Similarly, APOL3 can induce the fusion of intracellular bacterial membranes, and a role in membrane fusion can also be proposed for endothelial APOLd1 and adipocyte mAPOL6, which promote angiogenesis and adipogenesis, respectively, under inflammatory conditions. Thus, different APOL isoforms play distinct roles in membrane remodeling associated with inflammation.

Mycobacterium tuberculosis: The Mechanism of Pathogenicity, Immune Responses, and Diagnostic Challenges

BACKGROUND

The infection caused by Mycobacterium tuberculosis arises from a complex interplay between the host immune system and the bacteria. Early and effective treatment of this disease is of great importance in order to prevent the emergence of drug-resistant strains. This necessitates the availability of fast and reliable diagnostic methods for managing affected cases. One reason why this study is significant is the lack of a comprehensive review in this field that thoroughly examines the importance, pathogenesis, and diagnosis of M. tuberculosis. Therefore, the aim of this review is to provide updated information on M. tuberculosis.

METHODS

We investigate the virulence factors, pathogenicity, and diagnostic methods of this bacterium, alongside the clinical symptoms and interpretation of different types of tuberculosis, including cerebral, miliary, nerve, and tubercular tuberculosis.

RESULTS

Mycobacterium tuberculosis acts as the causative agent of human tuberculosis and is regarded as one of the most adaptable human pathogens. M. tuberculosis possesses several virulence factors that help the bacterium evade mucous barriers. The rise of multidrug-resistant tuberculosis (MDR-TB) in both developing and industrialized countries emphasizes the need for rapid diagnostic methods.

CONCLUSIONS

Non-protein virulence factors play a crucial role in the pathogenicity of Mycobacterium tuberculosis (M. tuberculosis). The bacterial cell membrane contains proteins that modulate the host immune response. For instance, ESAT-6, either alone or in combination with CFP-10, reduces immune activity. While molecular techniques-such as DNA microarray, luciferase reporter assay, polymerase chain reaction (PCR), DNA and RNA probes, next-generation sequencing, and whole-genome sequencing-offer rapid, sensitive, and specific detection of M. tuberculosis, these methods are expensive and require technical expertise.

The cGAS-STING pathway as a novel therapeutic strategy for pancreatic diseases

The Cyclic GMP-AMP synthase (cGAS)-Stimulator of interferon genes [1] signaling pathway has emerged as a pivotal immune response mechanism, activating immune defenses upon detection of both exogenous and endogenous DNA within cells. Its activation is intricately linked to various diseases and inflammatory processes, spanning autoimmune disorders, infectious ailments, and malignancies. Among pancreatic diseases, encompassing acute pancreatitis, chronic pancreatitis, and pancreatic cancer, current clinical treatment efficacy remains suboptimal. Here, we elucidate the molecular intricacies of the cGAS-STING signaling pathway and delineate its therapeutic potential in acute pancreatitis, chronic pancreatitis, and pancreatic cancer. Additionally, we offer an overview of recent advancements in STING agonists and antagonists, assessing their therapeutic potential in pancreatic-related disorders. In summary, by exploring the multifaceted roles of the cGAS-STING signaling pathway and its implications in pancreatic diseases, we aim to shed light on potential avenues for therapeutic intervention and management in these challenging clinical contexts.

A hypoxia-activated and microenvironment-remodeling nanoplatform for multifunctional imaging and potentiated immunotherapy of cancer

Activatable theranostic systems combining precise diagnosis and robust immune activation have significant potential in cancer treatment. Herein, we develop a versatile nanoplatform integrating hypoxia-activatable molecular imaging with effective photoimmunotherapy for cancer treatment. Our molecular probe features turn-on near-infrared-II (NIR-II) fluorescence and photoacoustic signals in hypoxic tumor environments. It also induces hypoxia-triggered photodynamic and photothermal effects, promoting immunogenic cell death and activating the STING pathway, engaging both innate and adaptive immunity. The molecular probe is formulated with a vascular disrupting agent to amplify the hypoxia-responsive phototheranostic properties, on which M1-like macrophage membrane is camouflaged to shield against premature release while conferring cancer-targeting affinity. The activatable NIR-II fluorescence and photoacoustic imaging enable precise tumor delineation, while the enhanced phototherapy activates tumor-specific cytotoxic T cells, impeding both primary and distant tumor progression and providing protective immunity against rechallenge in 4T1 tumor-bearing female mice. This work advances activatable theranostic protocols for image-guided immunotherapy.

New insights for the development of efficient DNA vaccines

Despite the great potential of DNA vaccines for a broad range of applications, ranging from prevention of infections, over treatment of autoimmune and allergic diseases to cancer immunotherapies, the implementation of such therapies for clinical treatment is far behind the expectations up to now. The main reason is the poor immunogenicity of DNA vaccines in humans. Consequently, the improvement of the performance of DNA vaccines in vivo is required. This mini-review provides an overview of the current state of DNA vaccines and the various strategies to enhance the immunogenic potential of DNA vaccines, including (i) the optimization of the DNA construct itself regarding size, nuclear transfer and transcriptional regulation; (ii) the use of appropriate adjuvants; and (iii) improved delivery, for example, by careful choice of the administration route, physical methods such as electroporation and nanomaterials that may allow cell type-specific targeting. Moreover, combining nanoformulated DNA vaccines with other immunotherapies and prime-boost strategies may help to enhance success of treatment.

cGAS/STING signalling pathway in senescence and oncogenesis

The cGAS/STING signaling pathway is a crucial component of the innate immune system, playing significant roles in sensing cytosolic DNA, regulating cellular senescence, and contributing to oncogenesis. Recent advances have shed new lights into the molecular mechanisms governing pathway activation in multiple pathophysiological settings, the indispensable roles of cGAS/STING signaling in cellular senescence, and its context-dependent roles in cancer development and suppression. This review summarizes current knowledge related to the biology of cGAS/STING signaling pathway and its participations into senescence and oncogenesis. We further explore the clinical implications and therapeutic potential for cGAS/STING targeted therapies, and faced challenges in the field. With a focus on molecular mechanisms and emerging pharmacological targets, this review underscores the importance of future studies to harness the therapeutic potential of the cGAS/STING pathway in treating senescence-related disorders and cancer. Advanced understanding of the regulatory mechanisms of cGAS/STING signaling, along with the associated deregulations in diseases, combined with the development of new classes of cGAS/STING modulators, hold great promises for creating novel and effective therapeutic strategies. These advancements could address current treatment challenges and unlock the full potential of cGAS/STING in treating senescence-related disorders and oncogenesis.

STING agonists and PI3Kγ inhibitor co-loaded ferric ion-punicalagin networks for comprehensive cancer therapy

Nanoparticles-based drug delivery system has been a promising approach for the treatment of colorectal cancer (CRC), which can be combined with chemotherapy, targeted therapy and immunotherapy to improve the treatment of CRC. 2'3' cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) is an agonist of the STING signaling pathway activating antitumor immunity. IPI-549 is a small-molecule inhibitor for phosphatidylinositol 3-kinase γ (PI3Kγ), which can induce M1 macrophages polarization to provide pro-inflammatory microenvironment to suppress tumors. Here, we developed a ferric ion-punicalagin network (Fe-PU), which can be not only used as an inducer of ferroptosis, but also serve as a carrier to load cGAMP and IPI-549 to obtain nanohybrid (Fe-PU/CD-IPI). In order to improve the delivery effect and targeted ability to CRC, a cyclic arginine-glycine-aspartic acid peptide linked-bovine serum albumin were utilized to modify Fe-PU/CD-IPI to prepare nanohybrid Fe-PU/CD-IPI@cBSA. The therapeutic effect of various nanohybrids were validated in the mice with spontaneous tumor in the colorectal area and tumor-bearing mice, which lead to the increase of ferroptosis, the activation of STING signaling pathway, and the repolarization of macrophages. Collectively, the cGAMP and IPI-549 co-loaded nanohybrids effectively reshaped the tumor immune microenvironment, and exhibited prominent treatment effect of anti-colorectal cancer in vitro, patient-derived organoids, and in vivo.

Recent advancements in cGAS-STING activation, tumor immune evasion, and therapeutic implications

The cGAS-STING signaling pathway is indeed a pivotal component of the immune system and serve as a crucial link between innate and adaptive immune responses. STING is involved in the cellular response to pathogen invasion and DNA damage, and which has important consequences for host defense mechanisms and cancer regulation. Ongoing research aiming to modulate the cGAS-STING pathway for improved clinical outcomes in cancer and autoimmune diseases is underway. Indeed, the interaction between the cGAS-STING pathway and immune evasion mechanisms is a complex and critical aspect of cancer biology. Pathogens and various host factors can exploit this pathway to reduce the effectiveness of cancer therapies, particularly immunotherapies. Thus, immunotherapies or combination therapies may assist in overcoming the immune suppression and improving clinical outcomes. This review explores recent advancements in understanding the cGAS-STING signaling pathway, with particular emphasis on its activation mechanisms and role in tumor immune evasion. The dual role of the pathway in boosting immune responses while simultaneously enabling tumors to evade the immune system makes it a crucial target for innovative cancer treatment approaches.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 2 Given name: [Md Mazedul] Last name [Islam], Author 3 Given name: [Mst Rubaiat Nazneen] Last name [Akhand] and Author 5 Given name: [Md Rashedunnabi] Last name [Akanda]. Also, kindly confirm the details in the metadata are correct.AQ1: Here Author 4 given name: [Byung-Yong] Last name [Park] is missing. Metadata are correct.

DNASE1L3-mediated PANoptosis enhances the efficacy of combination therapy for advanced hepatocellular carcinoma

Rationale: The introduction of combination therapy utilizing tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors for advanced hepatocellular carcinoma (HCC) has significantly altered the management of affected patients. However, the absence of predictive biomarkers to identify those who would derive the greatest benefit from this combination therapy underscores the necessity for further enhancements in its efficacy. Methods: In this study, we performed a proteomic analysis on surgical specimens from patients who either responded to or did not respond to combination therapy with sorafenib and programmed death-1 (PD-1) monoclonal antibody (mAb). We employed in vitro experiments, including immunocytochemistry, co-immunoprecipitation, and transmission electron microscopy, to elucidate the mechanism of DNASE1L3-induced PANoptosis. Additionally, we assessed the function of DNASE1L3 in combination therapy using a mouse liver orthotopic tumor model and clinical samples. Results: Our findings indicated that the levels of deoxyribonuclease 1 like 3 (DNASE1L3) were significantly elevated in the cohort of patients who responded to treatment, correlating with the sorafenib-induced programmed cell death (PCD) of HCC cells. Further experimentation revealed that DNASE1L3 facilitated the generation of double-strand deoxyribonucleic acid (dsDNA) breaks and activated the absent in melanoma 2 (AIM2) pathway during sorafenib-induced HCC cell death, ultimately culminating in PANoptosis. Moreover, DNASE1L3-induced PANoptosis augmented the activation of anti-tumor immunity within the tumor microenvironment (TME), thereby enhancing the efficacy of the combination therapy involving sorafenib and PD-1 mAb. Conclusion: Our findings offer valuable insights into the mechanisms underlying DNASE1L3's role in sorafenib sensitivity and position DNASE1L3 as a promising predictive biomarker and target for improving outcomes in combination therapy for HCC.

Loss of STING impairs lactogenic differentiation

Heightened energetic and nutrient demand during lactogenic differentiation of the mammary gland elicits upregulation of various stress responses to support cellular homeostasis. Here, we identify the stimulator of interferon genes (STING) as an immune supporter of the functional development of mouse mammary epithelial cells (MECs). An in vitro model of MEC differentiation revealed that STING is activated in a cGAS-independent manner to produce both type I interferons and proinflammatory cytokines in response to the accumulation of mitochondrial reactive oxygen species. Induction of STING activity was found to be dependent on the breast tumor suppressor gene single-minded 2 (SIM2). Using mouse models of lactation, we discovered that loss of STING activity results in early involution of #3 mammary glands, severely impairing lactational performance. Our data suggest that STING is required for successful functional differentiation of the mammary gland and bestows a differential lactogenic phenotype between #3 mammary glands and the traditionally explored inguinal 4|9 pair. These findings affirm unique development of mammary gland pairs that is essential to consider in future investigations into normal development and breast cancer initiation.

Regulation of Type I Interferon and Autophagy in Immunity against Mycobacterium Tuberculosis: Role of CGAS and STING1

Mycobacterium tuberculosis (M. tb) is a significant intracellular pathogen responsible for numerous infectious disease-related deaths worldwide. It uses ESX-1 T7SS to damage phagosomes and to enter the cytosol of host cells after phagocytosis. During infection, M. tb and host mitochondria release dsDNA, which activates the CGAS-STING1 pathway. This pathway leads to the production of type I interferons and proinflammatory cytokines and activates autophagy, which targets and degrades bacteria within autophagosomes. However, the role of type I IFNs in immunity against M. tb is controversial. While previous research has suggested a protective role, recent findings from cgas-sting1 knockout mouse studies have contradicted this. Additionally, a study using knockout mice and non-human primate models uncovered a new mechanism by which neutrophils recruited to lung infections form neutrophil extracellular traps. Activating plasmacytoid dendritic cells causes them to produce type I IFNs, which interfere with the function of interstitial macrophages and increase the likelihood of tuberculosis. Notably, M. tb uses its virulence proteins to disrupt the CGAS-STING1 signaling pathway leading to enhanced pathogenesis. Investigating the CGAS-STING1 pathway can help develop new ways to fight tuberculosis.

Impact of inorganic/organic nanomaterials on the immune system for disease treatment

The study of nanomaterials' nature, function, and biocompatibility highlights their potential in drug delivery, imaging, diagnostics, and therapeutics. Advancements in nanotechnology have fostered the development and application of diverse nanomaterials. These materials facilitate drug delivery and influence the immune system directly. Yet, understanding of their impact on the immune system is incomplete, underscoring the need to select materials to achieve desired outcomes carefully. In this review, we outline and summarize the distinctive characteristics and effector functions of inorganic nanomaterials and organic materials in inducing immune responses. We highlight the role and advantages of nanomaterial-induced immune responses in the treatment of immune-related diseases. Finally, we briefly discuss the current challenges and future opportunities for disease treatment and clinical translation of these nanomaterials.

Myotis bat STING attenuates aging-related inflammation in female mice

Bats, notable as the only flying mammals, serve as natural reservoir hosts for various highly pathogenic viruses in humans (e.g., SARS-CoV and Ebola virus). Furthermore, bats exhibit an unparalleled longevity among mammals relative to their size, particularly the Myotis bats, which can live up to 40 years. However, the mechanisms underlying these distinctive traits remain incompletely understood. In our prior research, we demonstrated that bats exhibit dampened STING-interferon activation, potentially conferring upon them the capacity to mitigate virus- or aging-induced inflammation. To substantiate this hypothesis, we established the first in vivo bat-mouse model for aging studies by integrating Myotis davidii bat STING ( MdSTING) into the mouse genome. We monitored the genotypes of these mice and performed a longitudinal comparative transcriptomic analysis on MdSTING and wild-type mice over a 3-year aging process. Blood transcriptomic analysis indicated a reduction in aging-related inflammation in female MdSTING mice, as evidenced by significantly lower levels of pro-inflammatory cytokines and chemokines, immunopathology, and neutrophil recruitment in aged female MdSTING mice compared to aged wild-type mice in vivo. These results indicated that MdSTING knock-in attenuates the aging-related inflammatory response and may also improve the healthspan in mice in a sex-dependent manner. Although the underlying mechanism awaits further study, this research has critical implications for bat longevity research, potentially contributing to our comprehension of healthy aging in humans.

Role of ferroptosis in the pathogenesis of heart disease

Ferroptosis is a new form of regulated necrosis characterized by iron-dependent lipid peroxidation, leading to irreparable lipid damage, membrane permeabilization, and necrotic cell death. Ferroptosis has recently been implicated in the pathogenesis of multiple forms of heart disease such as myocardial infarction, cardiac hypertrophy, heart failure, and various cardiomyopathies. Important progress has also been made regarding how ferroptosis is regulated in vitro and in vivo as well as its role in cardiac homeostasis and disease pathogenesis. In this review, we discuss molecular mechanisms that regulates ferroptosis in the heart, including pathways leading to iron overload and lipid peroxidation as well as the roles of key organelles in this process. We also discuss recent findings pertaining to the new pathogenic role of ferroptosis in various forms of heart disease as well as genetic and pharmacologic strategies targeting ferroptosis in the heart.

Tetrandrine activates STING/TBK1/IRF3 pathway to potentiate anti-PD-1 immunotherapy efficacy in non-small cell lung cancer

The efficacy of PD-1 therapy in non-small cell lung cancer (NSCLC) patients remains unsatisfactory. Activating the STING pathway is a promising strategy to improve PD-1 inhibitor efficacy. Here, we found tetrandrine (TET), an anti-tumor compound extracted from a medicinal plant commonly used in traditional Chinese medicine, has the ability to inhibit NSCLC tumor growth. Mechanistically, TET induces nuclear DNA damage and increases cytosolic dsDNA, thereby activating the STING/TBK1/IRF3 pathway, which in turn promotes the tumor infiltration of dendritic cells (DCs), macrophages, as well as CD8+ T cells in mice. In vivo imaging dynamically monitored the increased activity of the STING pathway after TET treatment and predicted the activation of the tumor immune microenvironment. We further revealed that the combination of TET with αPD-1 monoclonal antibody (αPD-1 mAb) yields significant anti-cancer effects by promoting CD8+ T cell infiltration and enhancing its cell-killing effect, which in turn reduced the growth of tumors and prolonged survival of NSCLC mice. Therefore, TET effectively eliminates NSCLC cells and enhances immunotherapy efficacy through the activation of the STING pathway, and combining TET with anti-PD-1 immunotherapy deserves further exploration for applications.

Activation of cGAS/STING Drives Inflammation and Cellular Senescence of Macrophages in Ovarian Endometrioma Induced by Endometriotic Cyst Fluid

Ovarian endometrioma (OE) is a common gynecological condition characterized by the formation of "chocolate cysts". Recent research indicates that the cyst fluid acts as a "toxic environment" for the ovary and plays a significant role in the development of OE, with macrophages being pivotal. However, the specific molecular and cellular mechanisms of it are not fully understood. In this study, clinical samples are integrated, single-cell sequencing, in vivo and in vitro experimental models to comprehensively investigate the effects of OE fluid on ovarian function and the mechanisms of it. Combined with bioinformatics analysis and experimental validation, the findings demonstrate that OE fluid can cause ovarian function decline, which associated with inflammatory response, and mitochondrial dysfunction and cellular senescence, while activating the cGAS/STING signaling pathway. As a STING inhibitor, H-151 effectively alleviates ovarian dysfunction, inflammatory state and cell apoptosis induced by OE fluid. Furthermore, it is also discovered that H-151 can inhibit OE fluid-induced mitochondrial dysfunction and cellular senescence. These findings provide important theoretical and experimental foundations for further research and development of STING inhibitors as potential drugs for treating ovarian dysfunction.

Pharmacological inhibition of cGAS ameliorates postoperative cognitive dysfunction by suppressing caspase-3/GSDME-dependent pyroptosis

Neuroinflammation is a major driver of postoperative cognitive dysfunction (POCD). The cyclic GMP-AMP synthase-stimulator of interferon gene (cGAS-STING) signaling is a prominent alarming device for aberrant double-stranded DNA (dsDNA) that has emerged as a key mediator of neuroinflammation in cognitive-related diseases. However, the role of the cGAS-STING pathway in the pathogenesis of POCD remains unclear. A POCD model was developed in male C57BL/6J mice by laparotomy under isoflurane (Iso) anesthesia. The cGAS inhibitor RU.521 and caspase-3 agonist Raptinal were delivered by intraperitoneal administration. BV2 cells were exposed to Iso and lipopolysaccharide (LPS) in the absence or presence of RU.521, and then cocultured with HT22 cells in the absence or presence of Raptinal. Cognitive function was assessed using the Morris water maze test and novel object recognition test. Immunofluorescence assays were used to observe the colocalization of dsDNA and cGAS. The downstream proteins and pro-inflammatory cytokines were detected using the Western blot and enzyme-linked immunosorbent assay (ELISA). Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was used to assess the degree of cell death in the hippocampus following anesthesia/surgery treatment. Isoflurane/laparotomy and Iso + LPS significantly augmented the levels of cGAS in the hippocampus and BV2 cells, accompanied by mislocalized dsDNA accumulation in the cytoplasm. RU.521 alleviated cognitive impairment, diminished the levels of 2'3'-cGAMP, cGAS, STING, phosphorylated NF-κB p65 and NF-κB-pertinent pro-inflammatory cytokines (TNFα and IL-6), and repressed pyroptosis-associated elements containing cleaved caspase-3, N-GSDME, IL-1β and IL-18. These phenotypes could be rescued by Raptinal in vivo and in vitro. These findings suggest that pharmacological inhibition of cGAS mitigates neuroinflammatory burden of POCD by dampening caspase-3/GSDME-dependent pyroptosis, providing a potential therapeutic strategy for POCD.

diABZI and poly(I:C) inhibit osteoclastic bone resorption by inducing IRF7 and IFIT3

Type I interferons (IFN-I) are pleiotropic factors endowed with multiple activities that play important roles in innate and adaptive immunity. Although many studies indicate that IFN-I inducers exert favorable effects on broad-spectrum antivirus, immunomodulation, and anti-tumor activities by inducing endogenous IFN-I and IFN-stimulated genes, their function in bone homeostasis still needs further exploration. Here, our study demonstrates 2 distinct IFN-I inducers, diABZI and poly(I:C), as potential therapeutics to alleviate osteolysis and osteoporosis. First, IFN-I inducers suppress the genes that control osteoclast (OC) differentiation and activity in vitro. Moreover, diABZI alleviates bone loss in Ti particle-induced osteolysis and ovariectomized -induced osteoporosis in vivo by inhibiting OC differentiation and function. In addition, the inhibitory effects of IFN-I inducers on OC differentiation are not observed in macrophages derived from Ifnar1-/-mice, which indicate that the suppressive effect of IFN-I inducers on OC is IFNAR-dependent. Mechanistically, RNAi-mediated silencing of IRF7 and IFIT3 in OC precursors impairs the suppressive effect of the IFN-I inducers on OC differentiation. Taken together, these results demonstrate that IFN-I inducers play a protective role in bone turnover by limiting osteoclastogenesis and bone resorption through the induction of OC-specific mediators via the IFN-I signaling pathway.

STING inhibition enables efficient plasmid-based gene expression in primary vascular cells: A simple and cost-effective transfection protocol

Plasmid transfection in cells is widely employed to express exogenous proteins, offering valuable mechanistic insight into their function(s). However, plasmid transfection efficiency in primary vascular endothelial cells (ECs) and smooth muscle cells (SMCs) is restricted with lipid-based transfection reagents such as Lipofectamine. The STING pathway, activated by foreign DNA in the cytosol, prevents foreign gene expression and induces DNA degradation. To address this, we explored the potential of STING inhibitors on the impact of plasmid expression in primary ECs and SMCs. Primary human aortic endothelial cells (HAECs) were transfected with a bicistronic plasmid expressing cytochrome b5 reductase 4 (CYB5R4) and enhanced green fluorescent protein (EGFP) using Lipofectamine 3000. Two STING inhibitors, MRT67307 and BX795, were added during transfection and overnight post-transfection. As a result, MRT67307 significantly enhanced CYB5R4 and EGFP expression, even 24 hours after its removal. In comparison, MRT67307 pretreatment did not affect transfection, suggesting the inhibitor's effect was readily reversible. The phosphorylation of endothelial nitric oxide synthase (eNOS) at Serine 1177 (S1177) by vascular endothelial growth factor is essential for endothelial proliferation, migration, and survival. Using the same protocol, we transfected wild-type and phosphorylation-incapable mutant (S1177A) eNOS in HAECs. Both forms of eNOS localized on the plasma membrane, but only the wild-type eNOS was phosphorylated by vascular endothelial growth factor treatment, indicating normal functionality of overexpressed proteins. MRT67307 and BX795 also improved plasmid expression in human and rat aortic SMCs. In conclusion, this study presents a modification enabling efficient plasmid transfection in primary vascular ECs and SMCs, offering a favorable approach to studying protein function(s) in these cell types, with potential implications for other primary cell types that are challenging to transfect.