DNA-stimulated cell death: implications for host defence, inflammatory diseases and cancer

Organelle-oriented nanomedicines in tumor therapy: Targeting, escaping, or collaborating?

Precise tumor therapy is essential for improving treatment specificity, enhancing efficacy, and minimizing side effects. Targeting organelles is a key strategy for achieving this goal and is a frontier research area attracting a considerable amount of attention. The concept of organelle targeting has a significant effect on the structural design of the nanodrugs employed. Most notably, the intricate interactions among different organelles in a tumor cell essentially create a unified system. Unfortunately, this aspect might have been somewhat overlooked when existing organelle-targeting nanodrugs were designed. In this review, we underscore the synergistic relationship among the various organelles and advocate for a holistic view of organelle-targeting design. Through the integration of biology and material science, recent advancements in organelle targeting, escaping, and collaborating are consolidated to offer fresh perspectives for the development of antitumor nanomedicines.

A Dual-Targeting T6SS DNase Drives Bacterial Antagonism and Eukaryotic Apoptosis via the cGAS-STING-TNF Axis

The Type VI secretion system (T6SS) is a key virulence mechanism utilized by many Gram-negative bacteria to mediate the microbial competition and host pathogenesis. Despite the identification of diverse T6SS effectors targeting eukaryotic or prokaryotic cells, the trans-kingdom T6SS effectors that simultaneously target both eukaryotic and prokaryotic cells remain rarely reported. In this study, it is demonstrated that Yersinia pseudotuberculosis (Yptb) T6SS secretes a DNase effector, TkeA, which induces apoptosis in host cells. The translocation of TkeA into host cells causes nuclear DNA damage. This, in turn, activates the DNA-sensing cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway. The activation of the cGAS-STING pathway by TkeA subsequently triggers apoptosis in host cells via extrinsic pathways, with tumor necrosis factor (TNF) signaling playing a critical role. Additionally, TkeA enhances bacterial competition by targeting rival bacteria, thereby promoting host colonization. These findings reveal that the transkingdom T6SS effector TkeA executes a "one weapon, two battlefields" strategy, acting as a trans-kingdom effector that enhances interbacterial competition while inducing apoptosis in host cells through the activation of the cGAS-STING-TNF axis. This highlights a previously unrecognized dimension of bacterial virulence strategies and expands the understanding of host-pathogen interactions involving T6SS effectors.

On the quest for undiscovered plant DNA receptors

The presence of unexpected DNA in cellular compartments acts as a danger signal that activates immune responses. In mammals, delocalized self-DNA triggers strong inflammatory responses crucial for antiviral immunity and cancer control. In plants, application of exogenous self-DNA increases resistance to pathogens and herbivores. Although several mammalian DNA receptors have been identified with distinct subcellular localizations and mechanisms to discriminate between microbial and mitochondrial DNA, no DNA receptors have been identified in plants. Here, we show current evidence for different potential response mechanisms for DNA perception and consider several hypothetical mechanisms for its recognition in plants. Finally, we provide a potential framework for finding plant self-DNA receptors in the future.

Immunological Effects of Proton Radiotherapy: New Opportunities and Challenges in Cancer Therapy

Radiation therapy can be categorised by particle type into photon, proton and heavy ion therapies. Proton radiotherapy is highlighted due to its unique physical properties, such as the Bragg peak and minimal exit dose, which offer superior dose distribution. This makes proton radiotherapy especially advantageous for treating tumours near vital organs with complex structures, such as gliomas near the brain, nasopharyngeal carcinoma near the brainstem and mediastinal tumours near the heart. Proton irradiation can induce distant effects through immunogenicity within the target area. The reduced low-dose zone outside the target provides better lymphatic system protection and immune benefits. Additionally, combining proton radiotherapy with immunotherapy may offer further biological advantages. These features make proton radiotherapy a promising option in cancer treatment. This article may aid in the understanding of proton radiotherapy and its immune effects and lead to new effective options for tumour treatment.

Organellophagy regulates cell death:A potential therapeutic target for inflammatory diseases

BACKGROUND

Dysregulated alterations in organelle structure and function have a significant connection with cell death, as well as the occurrence and development of inflammatory diseases. Maintaining cell viability and inhibiting the release of inflammatory cytokines are essential measures to treat inflammatory diseases. Recently, many studies have showed that autophagy selectively targets dysfunctional organelles, thereby sustaining the functional stability of organelles, alleviating the release of multiple cytokines, and maintaining organismal homeostasis. Organellophagy dysfunction is critically engaged in different kinds of cell death and inflammatory diseases.

AIM OF REVIEW

We summarized the current knowledge of organellophagy (e.g., mitophagy, reticulophagy, golgiphagy, lysophagy, pexophagy, nucleophagy, and ribophagy) and the underlying mechanisms by which organellophagy regulates cell death.

KEY SCIENTIFIC CONCEPTS OF REVIEW

We outlined the potential role of organellophagy in the modulation of cell fate during the inflammatory response to develop an intervention strategy for the organelle quality control in inflammatory diseases.

Cytosolic nucleic acid sensing as driver of critical illness: mechanisms and advances in therapy

Nucleic acids from both self- and non-self-sources act as vital danger signals that trigger immune responses. Critical illnesses such as acute respiratory distress syndrome, sepsis, trauma and ischemia lead to the aberrant cytosolic accumulation and massive release of nucleic acids that are detected by antiviral innate immune receptors in the endosome or cytosol. Activation of receptors for deoxyribonucleic acids and ribonucleic acids triggers inflammation, a major contributor to morbidity and mortality in critically ill patients. In the past decade, there has been growing recognition of the therapeutic potential of targeting nucleic acid sensing in critical care. This review summarizes current knowledge of nucleic acid sensing in acute respiratory distress syndrome, sepsis, trauma and ischemia. Given the extensive research on nucleic acid sensing in common pathological conditions like cancer, autoimmune disorders, metabolic disorders and aging, we provide a comprehensive summary of nucleic acid sensing beyond critical illness to offer insights that may inform its role in critical conditions. Additionally, we discuss potential therapeutic strategies that specifically target nucleic acid sensing. By examining nucleic acid sources, sensor activation and function, as well as the impact of regulating these pathways across various acute diseases, we highlight the driving role of nucleic acid sensing in critical illness.

Extracellular Mitochondria Exacerbate Retinal Pigment Epithelium Degeneration in Diabetic Retinopathy

Advancements in fundus imaging are revealing disruptions in the neurovascular unit in diabetic retinopathy (DR). In the era of anti-vascular endothelial growth factor treatment, a thorough characterization of neurodegeneration is imperative until patients with DR are sufficiently treated. Here, we demonstrate that extracellular mitochondria exacerbate retinal pigment epithelium (RPE) degeneration and inflammation in DR. Extracellular mitochondria increased in the vitreous of patients with DR and were associated with visual impairment but not with proliferative diabetic retinopathy or diabetic macular edema. Animal experiments demonstrated detrimental effects of extracellular mitochondria on RPE and photoreceptors. Lysosomal cell death induced by extracellular mitochondria in RPE cells required mitochondrial DNA but not its pattern recognition receptors. Furthermore, biochemical screening identified candidates for DNA receptors. Among them, DNA-dependent protein kinase was necessary for extracellular mitochondria-induced cell death in both in vitro and in vivo experiments. Extracellular mitochondria further induced interleukin-1β and tumor necrosis factor-α expression in RPE cells in a Toll-like receptor 9-dependent manner. RNA sequencing suggested that extracellular mitochondria exacerbate inflammation by promoting the proliferation and migration of macrophages, at least in part. In summary, extracellular mitochondria are designated as a novel exacerbating factor of RPE degeneration in DR.

ARTICLE HIGHLIGHTS

A therapeutic strategy for retinal pigment epithelium degeneration should be developed in diabetic retinopathy. We investigated the molecular mechanisms underpinning retinal pigment epithelium degeneration by extracellular mitochondria in diabetic retinopathy. Extracellular mitochondria were found in the vitreous humor of patients with diabetic retinopathy and exacerbated retinal pigment epithelium degeneration through DNA-dependent protein kinase, cytokine expression via Toll-like receptor 9, and macrophage activation. Extracellular mitochondria are designated as an aggravating factor of neurodegeneration and inflammation in diabetic retinopathy.

U-shaped association between plasma cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) levels and myocardial infarction

BACKGROUND

The cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) signaling pathway is closely associated with myocardial infarction (MI). Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) is a key component of this pathway; however, there is currently a lack of clinical evidence linking plasma cGAMP levels to MI.

METHODS

This study utilized clinical data from 270 patients diagnosed with coronary heart disease (CHD) at the Second Xiangya Hospital of Central South University. The outcomes included ST-segment elevation and non-ST-segment elevation MI. Univariate and multivariate logistic regression models were used to explore the relationships between plasma cGAMP levels and MI, while restricted cubic spline (RCS) using logistic regression to explore the dose-response relationship.

RESULTS

Among the 270 patients, the mean plasma cGAMP level was 1352.58 ± 106.02 ng/L and 89 (32.96%) patients were diagnosed with MI. The RCS curves indicated a U-shape association between the cGAMP levels and MI; the risk of MI was negatively correlated with the cGAMP until it hit bottoms at 1352 ng/L. When the cGAMP level exceeded 1352 ng/L, the risk of MI increased significantly (adjusted OR, 1.02; 95% CI: 1.01-1.03). When considering cGAMP as a categorical variable, patients in Tertile 1 and Tertile 3 had a 167% (adjusted OR: 2.67, 95% CI: 1.23-5.78) and 155% (adjusted OR: 2.55, 95% CI: 1.17-5.55) higher risk of MI compared to those in Tertile 2, respectively. These results were consistent across subgroup analyses, notably, a significant interaction by age category was observed in patients with cGAMP ≥ 1352 ng/L, where the positive association was pronounced in the elderly.

CONCLUSIONS

A U-shaped association exists between cGAMP and MI in the CHD population, with a cutoff point at the cGAMP of 1352 ng/L. Both excessively high and low cGAMP levels are associated with an increased risk of MI, particularly among the elderly with cGAMP ≥ 1352 ng/L. This is the first clinical evidence of the cGAS-cGAMP-STING pathway in metabolic cardiovascular diseases.

CLINICALTRIALS

GOV IDENTIFIER

NCT03363035 (Registration date: 2018-01-15).

Potential value of immunogenic cell death related-genes in refining European leukemiaNet guidelines classification and predicting the immune infiltration landscape in acute myeloid leukemia

Immunogenic cell death (ICD) is the kind of cell death that triggers the immune system. It affects several tumors, whereas its significance for prognosis in acute myeloid leukemia (AML) remains uncertain. AML categorization by cytogenetic variables is inaccurate. In addition, risk stratification of AML based on cytogenetics is imprecise. The data of AML patients were extracted from 4 databases, a total of 1,537 patients. Univariate and LASSO Cox regression analyses were conducted to construct an ICD risk signature (ICDRS). The ICDRS showed strong prognostic value for AML through Kaplan-Meier, Cox, ROC analyses and nomogram. Combining the ICDRS with the European LeukemiaNet (ELN) classification to redefine the risk stratification can better predict the prognosis of AML. Moreover, the ICDRS was examined to identify gene functional enrichment, immunological characteristics, drug susceptibility, and somatic mutation, which revealed considerable variations among different risk categories. We further validated the expression of ICDRS in the AML bone marrow microenvironment by single-cell RNA (scRNA) analysis. Ultimately, the functional role of CASP1 was proven in AML by a series of in-vitro experiments. Our study highlights the significant impact of ICDRS on AML, which may improve ELN risk classification, predict immune landscapes, and guide personalized therapy.

Ameliorating macrophage pyroptosis via ANXA1/NLRP3/Caspase-1/GSDMD pathway: Ac2-26/OGP-loaded intelligent hydrogel enhances bone healing in diabetic periodontitis

Craniofacial bone defect healing in periodontitis patients with diabetes background has long been difficult due to increased blood glucose levels which cause overproduction of reactive oxygen species (ROS) and a low pH environment. These conditions negatively affect the function of macrophages, worsen inflammation and oxidative stress, and ultimately, hinder osteoblasts' bone repair potential. In this study, we for the first time found that annexin A1 (ANXA1) expression in macrophages was reduced in a diabetic periodontitis (DP) environment, with the activation of the NLRP3/Caspase-1/GSDMD signaling pathway, and, eventually, increased macrophage pyroptosis. Next, we have developed a new GPPG intelligent hydrogel system which was ROS and pH responsive, and loaded with Ac2-26, an ANXA1 bioactive peptide, and osteogenic peptide OGP as well. We found that Ac2-26/OGP/GPPG can effectively reduce ROS, mitigates macrophage pyroptosis via the ANXA1/NLRP3/Caspase-1/GSDMD pathway and enhanced osteogenic differentiation. The effect of Ac2-26/OGP/GPPG in regulation of pyroptosis and bone defect repair was also further validated by animal experiments on periodontitis-induced tooth loss model in diabetic rats. To conclude, our study unveils the effect of ANXA1 on macrophage pyroptosis in periodontitis patients with diabetes, based on which we introduced a promising innovative hydrogel system for improvement of bone defects repair in DP patients via targeting macrophage pyroptosis and enhancing osteogenic potential.

Recombinant IL-34 alleviates bacterial enteritis in Megalobrama amblycephala by strengthening the intestinal barrier

The potential role of interleukin-34 (IL-34), an important cytokine that regulates intestinal function in mammals, is currently being explored in the context of fish intestinal diseases. In this study, we assessed the preventive potential of recombinant Megalobrama amblycephala IL-34 (rMaIL-34) protein in bacterial enteritis. MaIL-34 exhibited conserved structural and evolutionary features with teleost IL-34 and was found to be involved in the intestinal immune response to Aeromonas hydrophila infection. Furthermore, treatment with rMaIL-34 significantly improved the survival rate of M. amblycephala following A. hydrophila infection and alleviated the symptoms of enteritis in these fish. In vivo, rMaIL-34 enhanced goblet cell proliferation and mucus layer tightness, thereby maintaining mucosal integrity following infection. Additionally, rMaIL-34 attenuated the decrease in ZO-1 expression and inhibited the increase in intestinal permeability caused by A. hydrophila, thereby reducing the concentrations of DAO and D-LAC in the plasma. Furthermore, rMaIL-34 suppressed oxidative stress, apoptosis, and inflammatory responses triggered by A. hydrophila, thereby strengthening the immune barrier. At the microbiological level, rMaIL-34 contributed to improved intestinal microbiota distribution and enhanced the functions of intestinal microbiota in terms of energy metabolism, antibiotic biosynthesis, and oxidative phosphorylation. This study reveals, for the first time, the multiple roles of fish IL-34 in resistance to bacterial enteritis and paves the way for the development of rMaIL-34 as an immunotherapy for bacterial enteritis in fish.

Endoplasmic Reticulum Stress Nano-Orchestrators for Precisely Regulated Immunogenic Cell Death as Potent Cancer Vaccines

Dying tumor cells regulated by immunogenic cell death (ICD) inducers are promising candidates for cancer vaccine development because of their comprehensive antigen spectrum. However, their limited immunogenicity and potential tumorigenicity hinder clinical translation. To address these challenges, a nano-orchestrator is developed that targets the endoplasmic reticulum (ER) stress, a critical pre-ICD event, to optimize the "precise dose" of ER stress. Using a clinical-range irradiation fluence (50‒200 J cm-2) with an 808 nm laser, the release of damage associated molecular patterns (DAMPs) and antigens are precisely regulated. A fluence of 150 J cm-2 (2 W cm-2 for 75 s) increases dendritic cell maturation and antitumor T cell proliferation, providing valuable clinical insights. The ER stress nano-orchestrator enhances both adjuvanticity and antigenicity via the protein kinase R-like endoplasmic reticulum kinase (PERK)-C/EBP homologous protein (CHOP) pathway to regulate ICD-induced DAMPs and promote tumor cell apoptosis. These optimized ER stress phototherapeutic dying tumor cells can serve as prophylactic vaccines, achieving a remarkable 100% success rate against tumor rechallenge in vivo. Additionally, the nano-orchestrator shows the potential to develop in situ therapeutic tumor vaccines when combined with anti-PD-L1 treatment, providing important insights into enhancing the efficacy of immune checkpoint regulators by modulating endogenous immune responses.

Cas9-induced targeted integration of large DNA payloads in primary human T cells via homology-mediated end-joining DNA repair

The reliance on viral vectors for the production of genetically engineered immune cells for adoptive cellular therapies remains a translational bottleneck. Here we report a method leveraging the DNA repair pathway homology-mediated end joining, as well as optimized reagent composition and delivery, for the Cas9-induced targeted integration of large DNA payloads into primary human T cells with low toxicity and at efficiencies nearing those of viral vectors (targeted knock-in of 1-6.7 kb payloads at rates of up to 70% at multiple targeted genomic loci and with cell viabilities of over 80%). We used the method to produce T cells with an engineered T-cell receptor or a chimaeric antigen receptor and show that the cells maintained low levels of exhaustion markers and excellent capacities for proliferation and cytokine production and that they elicited potent antitumour cytotoxicity in vitro and in mice. The method is readily adaptable to current good manufacturing practices and scale-up processes, and hence may be used as an alternative to viral vectors for the production of genetically engineered T cells for cancer immunotherapies.

The role of post-translational modifications of cGAS in γδ T cells

Cyclic GMP-AMP (cGAMP) synthase (cGAS) senses DNA in a sequence-independent manner, triggering cGAMP synthesis, which activates stimulator of interferon genes (STING) and the subsequent expression of type I interferons, tumour necrosis factor alpha (TNF-α) and other proinflammatory factors in two downstream pathways. However, the function of the cGASSTING pathway in γδ T cells remains unclear. The γδ T-cell population differs from the innate-like lymphocyte population, particularly with respect to tissue distribution, indicating the unique potential of γδ T cells in treating infections and cancers. On the basis of accumulating evidence, cGAS activity is modulated by protein posttranslational modifications (PTMs), including phosphorylation, O-GlcNAcylation, acetylation, ubiquitylation and methylation, which affect multiple cGAS functions. Thus, here, we summarize recent research on PTMs of the cGAS protein that modulate γδ T-cell function. An understanding of cGAS features and modulation mechanisms may facilitate the design of therapies for γδ T-cell-related immune diseases and cancer.

Increased IFN-β indicates better survival in hepatocellular carcinoma treated with radiotherapy

Preclinical data suggest that type I interferon (IFN) responsiveness is essential for the antitumor effects of radiotherapy (RT). However, its clinical value remains unclear. This study aimed to explore this from a clinical perspective. In cohort 1, data from 152 hepatocellular carcinoma (HCC) patients who received RT were analyzed. Blood samples were taken 1 day before and 2 weeks after RT. RT was found to increase serum levels of IFN-β (a subtype of IFN-I) in HCC patients (3.42 ± 1.57 to 5.51 ± 2.11 pg/ml, P < 0.01), particularly in those with favorable responses. Higher post-RT serum IFN-β levels (≥4.77 pg/ml) were associated with better progression-free survival (HR = 0.58, P < 0.01). Cohort 2 included 46 HCC patients, including 23 who underwent preoperative RT and 23 matched control HCC who received surgical resection without RT. Formalin-fixed paraffin-embedded samples were obtained. Neoadjuvant RT significantly increased IFN-β expression in tumor tissues compared to direct surgery (8.13% ± 5.19% to 15.10% ± 5.89%, P < 0.01). Higher post-RT IFN-β (>median) indicated better disease-free survival (P = 0.049). Additionally, increased CD11c+MHCII+CD141+ antigen-presenting cell subsets and CD103+CD39+CD8+ tumor-infiltrating lymphocytes were found in the higher IFN-β group (P = 0.02, P = 0.03), which may contribute to the favorable prognosis in higher IFN-β group. Collectively, these findings suggest that IFN-β response activated by radiation may serve as a prognostic biomarker for HCC patients undergoing RT.

Macrophage variants in laboratory research: most are well done, but some are RAW

Macrophages play a pivotal role in the innate immune response. While their most characteristic function is phagocytosis, it is important not to solely characterize macrophages by this activity. Their crucial roles in body development, homeostasis, repair, and immune responses against pathogens necessitate a broader understanding. Macrophages exhibit remarkable plasticity, allowing them to modify their functional characteristics in response to the tissue microenvironment (tissue type, presence of pathogens or inflammation, and specific signals from neighboring cells) swiftly. While there is no single defined "macrophage" entity, there is a diverse array of macrophage types because macrophage ontogeny involves the differentiation of progenitor cells into tissue-resident macrophages, as well as the recruitment and differentiation of circulating monocytes in response to tissue-specific cues. In addition, macrophages continuously sense and respond to environmental cues and tissue conditions, adjusting their functional and metabolic states accordingly. Consequently, it is of paramount importance to comprehend the heterogeneous origins and functions of macrophages employed in in vitro studies, as each available in vitro macrophage model is associated with specific sets of strengths and limitations. This review centers its attention on a comprehensive comparison between immortalized mouse macrophage cell lines and primary mouse macrophages. It provides a detailed analysis of the strengths and weaknesses inherent in these in vitro models. Finally, it explores the subtle distinctions between diverse macrophage cell lines, offering insights into numerous factors beyond the model type that can profoundly influence macrophage function.

PARP inhibitors enhance antitumor immune responses by triggering pyroptosis via TNF-caspase 8-GSDMD/E axis in ovarian cancer

BACKGROUND

In addition to their established action of synthetic lethality in tumor cells, poly(ADP-ribose) polymerase inhibitors (PARPis) also orchestrate tumor immune microenvironment (TIME) that contributes to suppressing tumor growth. However, it remains not fully understood whether and how PARPis trigger tumor-targeting immune responses.

METHODS

To decode the immune responses reshaped by PARPis, we conducted T-cell receptor (TCR) sequencing and immunohistochemical (IHC) analyses of paired clinical specimens before and after niraparib monotherapy obtained from a prospective study, as well as ID8 mouse ovarian tumors. To validate the induction of immunogenic cell death (ICD) by PARPis, we performed immunofluorescence/IHC staining with homologous recombination deficiency tumor cells and patient-derived xenograft tumor tissues, respectively. To substantiate that PARPis elicited tumor cell pyroptosis, we undertook comprehensive assessments of the cellular morphological features, cleavage of gasdermin (GSDM) proteins, and activation of TNF-caspase signaling pathways through genetic downregulation/depletion and selective inhibition. We also evaluated the critical role of pyroptosis in tumor suppression and immune activation following niraparib treatment using a syngeneic mouse model with implanting CRISPR/Cas9 edited Gsdme-/ - ID8 tumor cells into C57BL/6 mice.

RESULTS

Our findings revealed that PARPis augmented the proportion of neoantigen-recognized TCR clones and TCR clonal expansion, and induced an inflamed TIME characterized by increased infiltration of both innate and adaptive immune cells. This PARPis-strengthened immune response was associated with the induction of ICD, specifically identified as pyroptosis, which possessed distinctive morphological features and GSDMD/E cleavage. It was validated that the cleavage of GSDMD/E was due to elevated caspase 8 activity downstream of the TNFR1, rather than FAS and TRAIL-R. On PARP inhibition, the NF-κB signaling pathway was activated, leading to increased secretion of TNF-α and subsequent initiation of the TNFR1-caspase 8 cascade. Impeding pyroptosis through the depletion of Gsdme significantly compromised the tumor-suppressing effects of PARP inhibition and undermined the anti-immune response in the syngeneic ID8 mouse model.

CONCLUSIONS

PARPis induce a specific type of ICD called pyroptosis via TNF-caspase 8-GSDMD/E axis, resulting in an inflamed TIME and augmentation of tumor-targeting immune responses. These findings deepen our understanding of PARPis activities and point toward a promising avenue for synergizing PARPis with immunotherapeutic interventions.

TRIAL REGISTRATION NUMBER

NCT04507841.

IFI-16 inhibition attenuates myocardial remodeling following myocardial infarction

Myocardial remodeling (MR) following myocardial infarction (MI) contributes to heart failure. Inflammation is a key determinant in cardiac remodeling, with potential prognostic improvements by inhibiting inflammatory factors. Pattern recognition receptors, including interferon gamma-inducible protein-16 (IFI-16), play significant roles in this process, yet its specific involvement remains underexplored. This study investigates IFI-16's role in initiating inflammation via the inflammasome and its direct interaction with galectin-3 protein post-MI. Elevated IFI-16 levels were observed in human and rat myocytes and a mouse MI model under hypoxic, nutrient-deprived conditions, correlating with increased inflammation-associated proteins. Suppression of IFI-16/IFI-204 using short hairpin RNA (shRNA) lentivirus or adeno-associated virus decreased inflammatory factor activation, thereby mitigating remodeling and enhancing cardiac function post-MI. Co-immunoprecipitation (coIP) and double-fluorescence staining confirmed IFI-16's ability to interact directly with galectin-3. These findings underscore IFI-16's critical role as a pro-inflammatory factor in post-MI MR, suggesting its inhibition as a potential therapeutic strategy.

Natural and socio-environmental factors in the transmission of COVID-19: a comprehensive analysis of epidemiology and mechanisms

PURPOSE OF REVIEW

There are significant differences in the transmission rate and mortality rate of COVID-19 under environmental conditions such as seasons and climates. However, the impact of environmental factors on the role of the COVID-19 pandemic and the transmission mechanism of the SARS-CoV-2 is unclear. Therefore, a comprehensive understanding of the impact of environmental factors on COVID-19 can provide innovative insights for global epidemic prevention and control policies and COVID-19 related research. This review summarizes the evidence of the impact of different natural and social environmental factors on the transmission of COVID-19 through a comprehensive analysis of epidemiology and mechanism research. This will provide innovative inspiration for global epidemic prevention and control policies and provide reference for similar infectious diseases that may emerge in the future.

RECENT FINDINGS

Evidence reveals mechanisms by which natural environmental factors influence the transmission of COVID-19, including (i) virus survival and transport, (ii) immune system damage, (iii) inflammation, oxidative stress, and cell death, and (iiii) increasing risk of complications. All of these measures appear to be effective in controlling the spread or mortality of COVID-19: (1) reducing air pollution levels, (2) rational use of ozone disinfection and medical ozone therapy, (3) rational exposure to sunlight, (4) scientific ventilation and maintenance of indoor temperature and humidity, (5) control of population density, and (6) control of population movement. Our review indicates that with the continuous mutation of SARS-CoV-2, high temperature, high humidity, low air pollution levels, and low population density more likely to slow down the spread of the virus.

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.

In Situ Aggregated Nanomanganese Enhances Radiation-Induced Antitumor Immunity

Radiosensitizers play a pivotal role in enhancing radiotherapy (RT). One of the challenges in RT is the limited accumulation of nanoradiosensitizers and the difficulty in activating antitumor immunity. Herein, a smart strategy was used to achieve in situ aggregation of nanomanganese adjuvants (MnAuNP-C&B) to enhance RT-induced antitumor immunity. The aggregated MnAuNP-C&B system overcomes the shortcomings of small-sized nanoparticles that easily flow back into blood vessels and diffuse into surrounding tissues, and it also prolongs the retention time of nanomanganese within cancer cells and tumors. The MnAuNP-C&B system significantly enhances the radiosensitization effect in RT. Additionally, the pH-responsive disassembly of MnAuNP-C&B triggers the release of Mn2+, further promoting RT-induced activation of the STING pathway and eliciting robust antitumor immunity. Overall, our study presents a smart strategy wherein in situ aggregation of nanomanganese effectively inhibits tumor growth through radiosensitization and the activation of antitumor immunity.

Cell toxicity assessment in co-treatment to metalworking fluids and vibration: an in vitro study of occupational exposure setting

This study was designed to study dual risk of MWFs and vibration according to exposure simulation of selected industry. Air samples of two types MWFs were evaluated according to NIOSH 5026. Vibration acceleration exposure was assessed based on the ISO 8041:2005 standard. Cell treatment of both MWF air samples and vibration as the same as dual exposure to MWF airborne and vibration was assessed. There is a potency of nitrosamine formation in airborne samples of ethylamine containing MWF, while heterocyclic including bore is found in airborne bore containing MWF. DNA breaks caused by boron-containing MWF were higher than nitrosamine air samples. Oxidative stress production and chronic inflammation were highlighted in the response to cell treatments. The risk of cell toxicity in machining workers was evaluated at a level lower than the occupational exposure limit for MWFs and vibration.

Protocol for isolating small cytosolic dsDNA from cultured murine cells

We recently identified a class of small cytosolic double-stranded DNA (scDNA) approximately 20-40 bp in size in human and mouse cells. Here, we present a protocol for scDNA isolation from cultured murine cells. We describe steps for cytosolic compartment separation, DNA isolation in the cytosolic fraction using phenol-chloroform extraction, and ethanol precipitation. We then detail procedures for denaturing purified cytosolic DNA through urea polyacrylamide gel electrophoresis and obtaining scDNA in the cytosolic DNA fraction via gel purification. For complete details on the use and execution of this protocol, please refer to Liu et al.1.

The landscape of programmed cell death-related lncRNAs in Alzheimer's disease and Parkinson's disease

This study delivers a thorough analysis of long non-coding RNAs (lncRNAs) in regulating programmed cell death (PCD), vital for neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD). We propose a new framework PCDLnc, and identified 20 significant lncRNAs, including HEIH, SNHG15, and SNHG5, associated with PCD gene sets, which were known for roles in proliferation and apoptosis in neurodegenerative diseases. By using GREAT software, we identified regulatory functions of top lncRNAs in different neurodegenerative diseases. Moreover, lncRNAs cis-regulated mRNAs linked to neurodegeneration, including JAK2, AKT1, EGFR, CDC42, SNCA, and ADIPOQ, highlighting their therapeutic potential in neurodegenerative diseases. A further exploration into the differential expression of mRNA identified by PCDLnc revealed a role in apoptosis, ferroptosis and autophagy. Additionally, protein-protein interaction (PPI) network analysis exposed abnormal interactions among key genes, despite their consistent expression levels between disease and normal samples. The randomforest model effectively distinguished between disease samples, indicating a high level of accuracy. Shared gene subsets in AD and PD might serve as potential biomarkers, along with disease-specific gene sets. Besides, we also found the strong relationship between AD and immune infiltration. This research highlights the role of lncRNAs and their associated genes in PCD in neurodegenerative diseases, offering potential therapeutic targets and diagnostic markers for future study and clinical application.

Berberine: Potential preventive and therapeutic strategies for human colorectal cancer

Colorectal cancer (CRC) is a common digestive tract tumor, with incidences continuing to rise. Although modern medicine has extended the survival time of CRC patients, its adverse effects and the financial burden cannot be ignored. CRC is a multi-step process and can be caused by the disturbance of gut microbiome and chronic inflammation's stimulation. Additionally, the presence of precancerous lesions is also a risk factor for CRC. Consequently, scientists are increasingly interested in identifying multi-target, safe, and economical herbal medicine and natural products. This paper summarizes berberine's (BBR) regulatory mechanisms in the occurrence and development of CRC. The findings indicate that BBR regulates gut microbiome homeostasis and controls mucosal inflammation to prevent CRC. In the CRC stage, BBR inhibits cell proliferation, invasion, and metastasis, blocks the cell cycle, induces cell apoptosis, regulates cell metabolism, inhibits angiogenesis, and enhances chemosensitivity. BBR plays a role in the overall management of CRC. Therefore, using BBR as an adjunct to CRC prevention and treatment could become a future trend in oncology.

Release of damaged mitochondrial DNA: A novel factor in stimulating inflammatory response

Mitochondrial DNA (mtDNA) is a circular double-stranded genome that exists independently of the nucleus. In recent years, research on mtDNA has significantly increased, leading to a gradual increase in understanding of its physiological and pathological characteristics. Reactive oxygen species (ROS) and other factors can damage mtDNA. This damaged mtDNA can escape from the mitochondria to the cytoplasm or extracellular space, subsequently activating immune signaling pathways, such as NLR family pyrin domain protein 3 (NLRP3), and triggering inflammatory responses. Numerous studies have demonstrated the involvement of mtDNA damage and leakage in the pathological mechanisms underlying various diseases including infectious diseases, metabolic inflammation, and immune disorders. Consequently, comprehensive investigation of mtDNA can elucidate the pathological mechanisms underlying numerous diseases. The prevention of mtDNA damage and leakage has emerged as a novel approach to disease treatment, and mtDNA has emerged as a promising target for drug development. This article provides a comprehensive review of the mechanisms underlying mtDNA-induced inflammation, its association with various diseases, and the methods used for its detection.

Adjuvant COX inhibition augments STING signaling and cytolytic T cell infiltration in irradiated 4T1 tumors

Immune therapy is the new frontier of cancer treatment. Therapeutic radiation is a known inducer of immune response and can be limited by immunosuppressive mediators including cyclooxygenase-2 (COX2) that is highly expressed in aggressive triple negative breast cancer (TNBC). A clinical cohort of TNBC tumors revealed poor radiation therapeutic efficacy in tumors expressing high COX2. Herein, we show that radiation combined with adjuvant NSAID (indomethacin) treatment provides a powerful combination to reduce both primary tumor growth and lung metastasis in aggressive 4T1 TNBC tumors, which occurs in part through increased antitumor immune response. Spatial immunological changes including augmented lymphoid infiltration into the tumor epithelium and locally increased cGAS/STING1 and type I IFN gene expression were observed in radiation-indomethacin-treated 4T1 tumors. Thus, radiation and adjuvant NSAID treatment shifts "immune desert phenotypes" toward antitumor M1/TH1 immune mediators in these immunologically challenging tumors. Importantly, radiation-indomethacin combination treatment improved local control of the primary lesion, reduced metastatic burden, and increased median survival when compared with radiation treatment alone. These results show that clinically available NSAIDs can improve radiation therapeutic efficacy through increased antitumor immune response and augmented local generation of cGAS/STING1 and type I IFNs.

Nanocarrier-based gene delivery for immune cell engineering

Clinical advances in genetically modified immune cell therapies, such as chimeric antigen receptor T cell therapies, have raised hope for cancer treatment. The majority of these biotechnologies are based on viral methods for ex vivo genetic modification of the immune cells, while the non-viral methods are still in the developmental phase. Nanocarriers have been emerging as materials of choice for gene delivery to immune cells. This is due to their versatile physicochemical properties such as large surface area and size that can be optimized to overcome several practical barriers to successful gene delivery. The in vivo nanocarrier-based gene delivery can revolutionize cell-based cancer immunotherapies by replacing the current expensive autologous cell manufacturing with an off-the-shelf biomaterial-based platform. The aim of this research is to review current advances and strategies to overcome the challenges in nanoparticle-based gene delivery and their impact on the efficiency, safety, and specificity of the process. The main focus is on polymeric and lipid-based nanocarriers, and their recent preclinical applications for cancer immunotherapy.

SAM68 directs STING signaling to apoptosis in macrophages

DNA is a danger signal sensed by cGAS to engage signaling through STING to activate innate immune functions. The best-studied downstream responses to STING activation include expression of type I interferon and inflammatory genes, but STING also activates other pathways, including apoptosis. Here, we report that STING-dependent induction of apoptosis in macrophages occurs through the intrinsic mitochondrial pathway and is mediated via IRF3 but acts independently of gene transcription. By intersecting four mass spectrometry datasets, we identify SAM68 as crucial for the induction of apoptosis downstream of STING activation. SAM68 is essential for the full activation of apoptosis. Still, it is not required for STING-mediated activation of IFN expression or activation of NF-κB. Mechanistic studies reveal that protein trafficking is required and involves SAM68 recruitment to STING upon activation, with the two proteins associating at the Golgi or a post-Golgi compartment. Collectively, our work identifies SAM68 as a STING-interacting protein enabling induction of apoptosis through this DNA-activated innate immune pathway.

Influence of the brain‑gut axis on neuroinflammation in cerebral ischemia‑reperfusion injury (Review)

Stroke, a debilitating cerebrovascular ailment, poses significant threats to human life and health. The intricate interplay between the gut‑brain‑microbiota axis (GBMA) and cerebral ischemia‑reperfusion has increasingly become a focal point of scientific exploration, emerging as a pivotal research avenue in stroke pathophysiology. In the present review, the authors delved into the nexus between the GBMA and neuroinflammation observed post‑stroke. The analysis underscored the pivotal roles of histone deacetylase 3 and neutrophil extracellular traps subsequent to stroke incidents. The influence of gut microbial compositions and their metabolites, notably short‑chain fatty acids and trimethylamine N‑oxide, on neuroinflammatory processes, was further elucidated. The involvement of immune cells, especially regulatory T‑cells, and the intricate signaling cascades including cyclic GMP‑AMP synthase/stimulator of interferon genes/Toll‑like receptor, further emphasized the complex regulatory mechanisms of GBMA in cerebral ischemia/reperfusion injury (CI/RI). Collectively, the present review offered a comprehensive perspective on the metabolic, immune and inflammatory modulations orchestrated by GBMA, augmenting the understanding of its role in neuroinflammation following CI/RI.

Targeting ATR Pathway in Solid Tumors: Evidence of Improving Therapeutic Outcomes

The DNA damage response (DDR) system is a complicated network of signaling pathways that detects and repairs DNA damage or induces apoptosis. Critical regulators of the DDR network include the DNA damage kinases ataxia telangiectasia mutated Rad3-related kinase (ATR) and ataxia-telangiectasia mutated (ATM). The ATR pathway coordinates processes such as replication stress response, stabilization of replication forks, cell cycle arrest, and DNA repair. ATR inhibition disrupts these functions, causing a reduction of DNA repair, accumulation of DNA damage, replication fork collapse, inappropriate mitotic entry, and mitotic catastrophe. Recent data have shown that the inhibition of ATR can lead to synthetic lethality in ATM-deficient malignancies. In addition, ATR inhibition plays a significant role in the activation of the immune system by increasing the tumor mutational burden and neoantigen load as well as by triggering the accumulation of cytosolic DNA and subsequently inducing the cGAS-STING pathway and the type I IFN response. Taken together, we review stimulating data showing that ATR kinase inhibition can alter the DDR network, the immune system, and their interplay and, therefore, potentially provide a novel strategy to improve the efficacy of antitumor therapy, using ATR inhibitors as monotherapy or in combination with genotoxic drugs and/or immunomodulators.

Pyroptosis in Osteoarthritis: Molecular Mechanisms and Therapeutic Implications

Osteoarthritis (OA) is a chronic disease that causes pain and functional impairment by affecting joint tissue. Its global impact is noteworthy, causing significant economic losses and property damage. Despite extensive research, the underlying pathogenesis of OA remain an area of ongoing investigation. It has recently been discovered that the OA progression is significantly influenced by pyroptosis. Pyroptosis is a complex process that involves three pathways culminating in the assembly of Gasdermin-D (GSDMD)-N-terminal (GSDMD-NT) into pores through aggregation on the plasma membrane. The aggregation of GSDMD-NT proteins stimulates the release of inflammatory mediators, such as Interleukin-1β (IL-1β), Interleukin-18 (IL-18), and Matrix Metallopeptidase 13 (MMP13), ultimately leading to cellular lysis. The pyroptosis process in specific cells, including synovial macrophages, fibroblast-like synoviocytes (FLS), chondrocytes, and subchondral osteoblasts, contributs factor to the development of OA. Currently, the specific cells that undergo pyroptosis first are not yet fully understood, and it remains unknown whether pyroptosis in one cell can trigger the same process in other cells. Therefore, targeting pyroptosis could potentially offer a novel treatment approach for OA patients. We present a comprehensive analysis of the molecular mechanisms and key features of pyroptosis. We also outline the current research progress on various aspects, including synovial tissue, articular cartilage, extracellular matrix (ECM), and subchondral bone, with a focus on pyroptosis. The aim is to provide theoretical references for the effective management of OA.

Cardiovascular diseases crossroads: cGAS-STING signaling and disease progression

It is now widely accepted that inflammation is critical in cardiovascular diseases (CVD). Here, studies are being conducted on how cyclic GMP-AMP synthase (cGAS), a component of innate immunity's DNA-sensing machinery, communicates with the STING receptor, which is involved in activating the immune system's antiviral response. Significantly, a growing body of research in recent years highlights the strong activation of the cGAS-STING signalling pathways in several cardiovascular diseases, such as myocardial infarction, heart failure, and myocarditis. This developing collection of research emphasises these pathways' crucial role in initiating and advancing cardiovascular disease. In this extensive narrative, we explore the role of the cGAS-STING pathway in the development of CVD. We elaborate on the basic mechanisms involved in the onset and progression of CVD. This review explores the most recent developments in the recognition and characterization of cGAS-STING pathway. Additionally, it considers the field's future prospects while examining how cGAS-STING pathway might be altered and its clinical applications for cardiovascular diseases.

Herpes simplex virus infection induces necroptosis of neurons and astrocytes in human fetal organotypic brain slice cultures

BACKGROUND

Herpes simplex virus (HSV) encephalitis (HSE) is a serious and potentially life-threatening disease, affecting both adults and newborns. Progress in understanding the virus and host factors involved in neonatal HSE has been hampered by the limitations of current brain models that do not fully recapitulate the tissue structure and cell composition of the developing human brain in health and disease. Here, we developed a human fetal organotypic brain slice culture (hfOBSC) model and determined its value in mimicking the HSE neuropathology in vitro.

METHODS

Cell viability and tissues integrity were determined by lactate dehydrogenase release in supernatant and immunohistological (IHC) analyses. Brain slices were infected with green fluorescent protein (GFP-) expressing HSV-1 and HSV-2. Virus replication and spread were determined by confocal microscopy, PCR and virus culture. Expression of pro-inflammatory cytokines and chemokines were detected by PCR. Cell tropism and HSV-induced neuropathology were determined by IHC analysis. Finally, the in situ data of HSV-infected hfOBSC were compared to the neuropathology detected in human HSE brain sections.

RESULTS

Slicing and serum-free culture conditions were optimized to maintain the viability and tissue architecture of ex vivo human fetal brain slices for at least 14 days at 37 °C in a CO2 incubator. The hfOBSC supported productive HSV-1 and HSV-2 infection, involving predominantly infection of neurons and astrocytes, leading to expression of pro-inflammatory cytokines and chemokines. Both viruses induced programmed cell death-especially necroptosis-in infected brain slices at later time points after infection. The virus spread, cell tropism and role of programmed cell death in HSV-induced cell death resembled the neuropathology of HSE.

CONCLUSIONS

We developed a novel human brain culture model in which the viability of the major brain-resident cells-including neurons, microglia, astrocytes and oligodendrocytes-and the tissue architecture is maintained for at least 2 weeks in vitro under serum-free culture conditions. The close resemblance of cell tropism, spread and neurovirulence of HSV-1 and HSV-2 in the hfOBSC model with the neuropathological features of human HSE cases underscores its potential to detail the pathophysiology of other neurotropic viruses and as preclinical model to test novel therapeutic interventions.

Cell death proteins in sepsis: key players and modern therapeutic approaches

Cell death proteins play a central role in host immune signaling during sepsis. These interconnected mechanisms trigger cell demise via apoptosis, necroptosis, and pyroptosis while also driving inflammatory signaling. Targeting cell death mediators with novel therapies may correct the dysregulated inflammation seen during sepsis and improve outcomes for septic patients.

A Nanoinhibitor Targeting cGAS-STING Pathway to Reverse the Homeostatic Imbalance of Inflammation in Psoriasis

Psoriasis is a chronic skin inflammation characterized by dysregulated crosstalk between immune cells and keratinocytes. Here we show that the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is a key regulator of psoriatic inflammation in a mouse model. Platinum-doped positively charged carbon dots (Pt-CDs) were designed to inhibit the cGAS-STING pathway. By inhibiting the cGAS-STING pathway with Pt-CDs, the secretion of proinflammatory cytokines in macrophages was reduced, and the proinflammatory cytokines-induced breakdown of immunological tolerance and overexpression of chemokines in keratinocytes was restored, which reversed the homeostatic imbalance through breaking these cytokines-mediated intercellular positive feedback loop. Topical Pt-CDs treatment exhibited therapeutic effects in imiquimod-induced psoriasis mice without noticeable toxicity. The reversal of elevated expression of STING, phosphorylated STING, and downstream genes within psoriatic lesions indicates that Pt-CDs effectively inhibit the cGAS-STING pathway. This work suggests a promising strategy for psoriasis treatment by targeting the cGAS-STING pathway with Pt-CDs nanoinhibitor to restore skin homeostatic balance.

Type I interferon and cancer

Type I interferon (IFN) is a class of proinflammatory cytokines with a dual role on malignant transformation, tumor progression, and response to therapy. On the one hand, robust, acute, and resolving type I IFN responses have been shown to mediate prominent anticancer effects, reflecting not only their direct cytostatic/cytotoxic activity on (at least some) malignant cells, but also their pronounced immunostimulatory functions. In line with this notion, type I IFN signaling has been implicated in the antineoplastic effects of various immunogenic therapeutics, including (but not limited to) immunogenic cell death (ICD)-inducing agents and immune checkpoint inhibitors (ICIs). On the other hand, weak, indolent, and non-resolving type I IFN responses have been demonstrated to support tumor progression and resistance to therapy, reflecting the ability of suboptimal type I IFN signaling to mediate cytoprotective activity, promote stemness, favor tolerance to chromosomal instability, and facilitate the establishment of an immunologically exhausted tumor microenvironment. Here, we review fundamental aspects of type I IFN signaling and their context-dependent impact on malignant transformation, tumor progression, and response to therapy.

PARP7-mediated ADP-ribosylation of FRA1 promotes cancer cell growth by repressing IRF1- and IRF3-dependent apoptosis

PARP7 was reported to promote tumor growth in a cell-autonomous manner and by repressing the antitumor immune response. Nevertheless, the molecular mechanism of how PARP7-mediated ADP-ribosylation exerts these effects in cancer cells remains elusive. Here, we identified PARP7 as a nuclear and cysteine-specific mono-ADP-ribosyltransferase that modifies targets critical for regulating transcription, including the AP-1 transcription factor FRA1. Loss of FRA1 ADP-ribosylation via PARP7 inhibition by RBN-2397 or mutation of the ADP-ribosylation site C97 increased FRA1 degradation by the proteasome via PSMC3. The reduction in FRA1 protein levels promoted IRF1- and IRF3-dependent cytokine as well as proapoptotic gene expression, culminating in CASP8-mediated apoptosis. Furthermore, high PARP7 expression was indicative of the PARP7 inhibitor response in FRA1-positive lung and breast cancer cells. Collectively, our findings highlight the connected roles of PARP7 and FRA1 and emphasize the clinical potential of PARP7 inhibitors for FRA1-driven cancers.

NeuroD1-GPX4 signaling leads to ferroptosis resistance in hepatocellular carcinoma

Cell death resistance is a hallmark of tumor cells that drives tumorigenesis and drug resistance. Targeting cell death resistance-related genes to sensitize tumor cells and decrease their cell death threshold has attracted attention as a potential antitumor therapeutic strategy. However, the underlying mechanism is not fully understood. Recent studies have reported that NeuroD1, first discovered as a neurodifferentiation factor, is upregulated in various tumor cells and plays a crucial role in tumorigenesis. However, its involvement in tumor cell death resistance remains unknown. Here, we found that NeuroD1 was highly expressed in hepatocellular carcinoma (HCC) cells and was associated with tumor cell death resistance. We revealed that NeuroD1 enhanced HCC cell resistance to ferroptosis, a type of cell death caused by aberrant redox homeostasis that induces lipid peroxide accumulation, leading to increased HCC cell viability. NeuroD1 binds to the promoter of glutathione peroxidase 4 (GPX4), a key reductant that suppresses ferroptosis by reducing lipid peroxide, and activates its transcriptional activity, resulting in decreased lipid peroxide and ferroptosis. Subsequently, we showed that NeuroD1/GPX4-mediated ferroptosis resistance was crucial for HCC cell tumorigenic potential. These findings not only identify NeuroD1 as a regulator of tumor cell ferroptosis resistance but also reveal a novel molecular mechanism underlying the oncogenic function of NeuroD1. Furthermore, our findings suggest the potential of targeting NeuroD1 in antitumor therapy.

Polyamine metabolism controls B-to-Z DNA transition to orchestrate DNA sensor cGAS activity

Cyclic guanosine monophosphate (GMP)-AMP (cGAMP) synthase (cGAS) is a universal double-stranded DNA (dsDNA) sensor that recognizes foreign and self-DNA in the cytoplasm and initiates innate immune responses and has been implicated in various infectious and non-infectious contexts. cGAS binds to the backbone of dsDNA and generates the second messenger, cGAMP, which activates the stimulator of interferon genes (STING). Here, we show that the endogenous polyamines spermine and spermidine attenuated cGAS activity and innate immune responses. Mechanistically, spermine and spermidine induced the transition of B-form DNA to Z-form DNA (Z-DNA), thereby decreasing its binding affinity with cGAS. Spermidine/spermine N1-acetyltransferase 1 (SAT1), the rate-limiting enzyme in polyamine catabolism that decreases the cellular concentrations of spermine and spermidine, enhanced cGAS activation by inhibiting cellular Z-DNA accumulation; SAT1 deficiency promoted herpes simplex virus 1 (HSV-1) replication in vivo. The results indicate that spermine and spermidine induce dsDNA to adopt the Z-form conformation and that SAT1-mediated polyamine metabolism orchestrates cGAS activity.

Trimethyltin chloride induces apoptosis and DNA damage via ROS/NF-κB in grass carp liver cells causing immune dysfunction

Trimethyltin chloride (TMT), a common component in fungicides and plastic stabilizers, presents environmental risks, particularly to fish farming. The precise toxicological mechanisms of TMT in L8824 grass carp liver cells remain undefined. Our study investigates TMT's effects on these cells, focusing on its potential to induce hepatotoxicity via oxidative stress and NF-κB pathway activation. First, we selected 0, 3, 6, and 12 μM as the challenge doses, according to the inhibitory concentration of 50% (IC50) of TMT. Our results demonstrate that TMT decreases cell viability dose-dependently and triggers oxidative stress, as evidenced by increased ROS staining and MDA content. Concurrently, it inhibited the antioxidant activities of T-AOC, T-SOD, CAT, and GSH. The activation of the NF-κB pathway was confirmed by gene expression changes. Furthermore, we observed an increase in cell apoptosis rate by AO/EB staining and cell flow cytometry, and the downregulation of Bcl-2 and the upregulation of Bax, Cytc, Caspase-9, and casp3 verified that TMT passed through the BCL2/BAX/casp3 pathway induces apoptosis. DNA damage was validated by the comet assay and γH2AX gene overexpression. Lastly, our data showed increased expression of TNF-α, IL-1β, IL-6, and INF-γ and decreased antimicrobial peptides, validating immune dysfunction. In conclusion, our findings establish that TMT induces apoptosis and DNA damage via ROS/NF-κB in grass carp liver cells, causing immune dysfunction. This study provides novel insights into the toxicology research of TMT and sheds light on the immunological effects of TMT toxicity, enriching our understanding of the immunotoxicity of TMT on aquatic organisms and contributing to the protection of ecosystems.

Targeting STING in cancer: Challenges and emerging opportunities

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway is a key pathway through which the host regulates immune responses by recognizing cytoplasmic double-stranded DNA of abnormal origin, and it plays an important role in tumor growth as well as metastasis, with relevant molecular details constantly being explored and updated. The significant immunomodulatory effects make STING an attractive target for cancer immunotherapy, and STING agonists have been receiving great attention for their development and clinical translation. Despite exciting results in preclinical work, the application of STING agonists to cancer therapy remains challenging due to their poor pharmacokinetic and physicochemical properties, as well as toxic side effects they produce. Here, we summarize the dichotomous role of cGAS-STING in cancer and discuss the limitations of cancer immunotherapy based on STING activation as well as feasible strategies to overcome them to achieve tumor regression.

The implication of pyroptosis in cancer immunology: Current advances and prospects

Pyroptosis is a regulated cell death pathway involved in numerous human diseases, especially malignant tumors. Recent studies have identified multiple pyroptosis-associated signaling molecules, like caspases, gasdermin family and inflammasomes. In addition, increasing in vitro and in vivo studies have shown the significant linkage between pyroptosis and immune regulation of cancers. Pyroptosis-associated biomarkers regulate the infiltration of tumor immune cells, such as CD4+ and CD8+ T cells, thus strengthening the sensitivity to therapeutic strategies. In this review, we explained the relationship between pyroptosis and cancer immunology and focused on the significance of pyroptosis in immune regulation. We also proposed the future application of pyroptosis-associated biomarkers in basic research and clinical practices to address malignant behaviors. Exploration of the underlying mechanisms and biological functions of pyroptosis is critical for immune response and cancer immunotherapy.

Novel insight into cGAS-STING pathway in ischemic stroke: from pre- to post-disease

Ischemic stroke, a primary cause of disability and the second leading cause of mortality, has emerged as an urgent public health issue. Growing evidence suggests that the Cyclic GMP-AMP synthase (cGAS)- Stimulator of interferon genes (STING) pathway, a component of innate immunity, is closely associated with microglia activation, neuroinflammation, and regulated cell death in ischemic stroke. However, the mechanisms underlying this pathway remain inadequately understood. This article comprehensively reviews the existing literature on the cGAS-STING pathway and its multifaceted relationship with ischemic stroke. Initially, it examines how various risk factors and pre-disease mechanisms such as metabolic dysfunction and senescence (e.g., hypertension, hyperglycemia, hyperlipidemia) affect the cGAS-STING pathway in relation to ischemic stroke. Subsequently, we explore in depth the potential pathophysiological relationship between this pathway and oxidative stress, endoplasmic reticulum stress, neuroinflammation as well as regulated cell death including ferroptosis and PANoptosis following cerebral ischemia injury. Finally, it suggests that intervention targeting the cGAS-STING pathway may serve as promising therapeutic strategies for addressing neuroinflammation associated with ischemic stroke. Taken together, this review concludes that targeting the microglia cGAS-STING pathway may shed light on the exploration of new therapeutic strategies against ischemic stroke.

RU.521 mitigates subarachnoid hemorrhage-induced brain injury via regulating microglial polarization and neuroinflammation mediated by the cGAS/STING/NF-κB pathway

BACKGROUND

The poor prognosis of subarachnoid hemorrhage (SAH) is often attributed to neuroinflammation. The cGAS-STING axis, a cytoplasmic pathway responsible for detecting dsDNA, plays a significant role in mediating neuroinflammation in neurological diseases. However, the effects of inhibiting cGAS with the selective small molecule inhibitor RU.521 on brain injury and the underlying mechanisms after SAH are still unclear.

METHODS

The expression and microglial localization of cGAS following SAH were investigated with western blot analysis and immunofluorescent double-staining, respectively. RU.521 was administered after SAH. 2'3'-cGAMP, a second messenger converted by activated cGAS, was used to activate cGAS-STING. The assessments were carried out by adopting various techniques including neurological function scores, brain water content, blood-brain barrier permeability, western blot analysis, TUNEL staining, Nissl staining, immunofluorescence, morphological analysis, Morris water maze test, Golgi staining, CCK8, flow cytometry in the in vivo and in vitro settings.

RESULTS

Following SAH, there was an observed increase in the expression levels of cGAS in rat brain tissue, with peak levels observed at 24 h post-SAH. RU.521 resulted in a reduction of brain water content and blood-brain barrier permeability, leading to an improvement in neurological deficits after SAH. RU.521 had beneficial effects on neuronal apoptosis and microglia activation, as well as improvements in microglial morphology. Additionally, RU.521 prompted a shift in microglial phenotype from M1 to M2. We also noted a decrease in the production of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6, and an increase in the level of the anti-inflammatory cytokine IL-10. Finally, RU.521 treatment was associated with improvements in cognitive function and an increase in the number of dendritic spines in the hippocampus. The therapeutic effects were mediated by the cGAS/STING/NF-κB pathway and were found to be abolished by 2'3'-cGAMP. In vitro, RU.521 significantly reduced apoptosis and neuroinflammation.

CONCLUSION

The study showed that SAH leads to neuroinflammation caused by microglial activation, which contributes to early brain injury. RU.521 improved neurological outcomes and reduced neuroinflammation by regulating microglial polarization through the cGAS/STING/NF-κB pathway in early brain injury after SAH. RU.521 may be a promising candidate for the treatment of neuroinflammatory pathology after SAH. Video Abstract.

Mechanisms of Extraorbital Lacrimal Gland Aging in Mice: An Integrative Analysis of the Temporal Transcriptome

Purpose

This study used high-throughput RNA sequencing (RNA-Seq) and bioinformatics analysis to investigate the altered transcriptome profile of aging lacrimal glands in mice that occurs over the course of a 24-hour cycle.

Methods

Male C57BL/6J mice aged 12 weeks (young) and 20 months (aging) were housed in a pathogen-free setting with a 12-hour light/12-hour dark cycle. Throughout a 24-hour cycle, mouse extraorbital lacrimal glands (ELGs) were collected at eight time points at three-hour intervals. To prepare for the high-throughput RNA-Seq, whole mRNA was extracted. Differentially expressed genes (DEGs) in the young and aging groups were subjected to bioinformatic analysis based on diurnal patterns. Furthermore, the cell populations in which significant DEGs express and signaling pathways occur were validated at the single-cell RNA sequencing (scRNA-seq) level.

Results

The total transcriptome composition was significantly altered in aging ELGs compared with that in young mouse ELGs at eight time points during the 24-hour cycle, with 864 upregulated and 228 downregulated DEGs, which were primarily enriched in inflammatory pathways. Further comparative analysis of the point-to-point transcriptome revealed that aging ELGs underwent alterations in the temporal transcriptome profile in several pathways, including the inflammation-related, metabolism-related, mitochondrial bioenergetic function-associated, synaptome neural activity-associated, cell processes-associated, DNA processing-associated and fibrosis-associated pathways. Most of these pathways occurred separately in distinct cell populations.

Conclusions

Transcriptome profiles of aging lacrimal glands undergo considerable diurnal time-dependent changes; this finding offers a comprehensive source of information to better understand the pathophysiology of lacrimal gland aging and its underlying mechanisms.

Activation of the cGAS/STING Axis in Genome-Damaged Hematopoietic Cells Does Not Impact Blood Cell Formation or Leukemogenesis

Genome damage is a main driver of malignant transformation, but it also induces aberrant inflammation via the cGAS/STING DNA-sensing pathway. Activation of cGAS/STING can trigger cell death and senescence, thereby potentially eliminating genome-damaged cells and preventing against malignant transformation. Here, we report that defective ribonucleotide excision repair (RER) in the hematopoietic system caused genome instability with concomitant activation of the cGAS/STING axis and compromised hematopoietic stem cell function, ultimately resulting in leukemogenesis. Additional inactivation of cGAS, STING, or type I IFN signaling, however, had no detectable effect on blood cell generation and leukemia development in RER-deficient hematopoietic cells. In wild-type mice, hematopoiesis under steady-state conditions and in response to genome damage was not affected by loss of cGAS. Together, these data challenge a role of the cGAS/STING pathway in protecting the hematopoietic system against DNA damage and leukemic transformation.

SIGNIFICANCE

Loss of cGAS/STING signaling does not impact DNA damage-driven leukemogenesis or alter steady-state, perturbed or malignant hematopoiesis, indicating that the cGAS/STING axis is not a crucial antioncogenic mechanism in the hematopoietic system. See related commentary by Zierhut, p. 2807.

Small cytosolic double-stranded DNA represses cyclic GMP-AMP synthase activation and induces autophagy

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is a major mediator of inflammation following stimulation with >45 bp double-stranded DNA (dsDNA). Herein, we identify a class of ∼20-40 bp small cytosolic dsDNA (scDNA) molecules that compete with long dsDNA (200-1,500 bp herring testis [HT]-DNA) for binding to cGAS, thus repressing HT-DNA-induced cGAS activation. The scDNA promotes cGAS and Beclin-1 interaction, releasing Rubicon, a negative regulator of phosphatidylinositol 3-kinase class III (PI3KC3), from the Beclin-1-PI3KC3 complex. This leads to PI3KC3 activation and induces autophagy, causing degradation of STING and long cytosolic dsDNA. Moreover, DNA damage decreases, and autophagy inducers increase scDNA levels. scDNA transfection and treatment with autophagy inducers attenuate DNA damage-induced cGAS activation. Thus, scDNA molecules serve as effective brakes for cGAS activation, preventing excessive inflammatory cytokine production following DNA damage. Our findings may have therapeutic implications for cytosolic DNA-associated inflammatory diseases.

Significance of the cGAS-STING Pathway in Health and Disease

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a significant role in health and disease. In this pathway, cGAS, one of the major cytosolic DNA sensors in mammalian cells, regulates innate immunity and the STING-dependent production of pro-inflammatory cytokines, including type-I interferon. Moreover, the cGAS-STING pathway is integral to other cellular processes, such as cell death, cell senescence, and autophagy. Activation of the cGAS-STING pathway by "self" DNA is also attributed to various infectious diseases and autoimmune or inflammatory conditions. In addition, the cGAS-STING pathway activation functions as a link between innate and adaptive immunity, leading to the inhibition or facilitation of tumorigenesis; therefore, research targeting this pathway can provide novel clues for clinical applications to treat infectious, inflammatory, and autoimmune diseases and even cancer. In this review, we focus on the cGAS-STING pathway and its corresponding cellular and molecular mechanisms in health and disease.

Role of cGAS-STING signaling pathway in cardiometabolic diseases

Cardiometabolic disease is a common clinical syndrome with exact causal relationship between the aberrant of glucose/lipid metabolism and cardiovascular disfunction, but its pathogenesis is unclear. Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon gene (STING) signaling pathway regulates the activation of innate immunity by sensing intracellular double stranded DNA. Metabolic risk factors drive the activation of cGAS-STING pathway through mitochondrial DNA, nuclear DNA and endoplasmic reticulum stress. In addition, the activation of the cGAS-STING pathway triggers chronic sterile inflammation, excessive activation of autophagy, senescence and apoptosis in related cells of cardiovascular system. These changes induced by cGAS-STING pathway might be implicated in the onset and deterioration of cardiometabolic disease. Therefore, the targeting intervention of cGAS-STING signaling pathway may emerge as a novel treatment for cardiometabolic disease.