Mitochondrial DNA-triggered innate immune response: mechanisms and diseases

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.

Microplastics/nanoplastics contribute to aging and age-related diseases: Mitochondrial dysfunction as a crucial role

The pervasive utilization of plastic products has led to a significant escalation in plastic waste accumulation. Concurrently, the implications of emerging pollutants such as microplastics (MPs) and nanoplastics (NPs) on human health are increasingly being acknowledged. Recent research has demonstrated that MPs/NPs may contribute to the onset of human aging and age-related diseases. Additionally, MPs/NPs have the potential to induce mitochondrial damage, resulting in mitochondrial dysfunction. Mitochondrial dysfunction is widely recognized as a hallmark of aging; thus, it is necessary to elucidate the relationship between them. In this article, we first elucidate the distribution of MPs/NPs in various environmental media, their pathways into the human body, and their subsequent distribution within human tissues and organs. Subsequently, we examine the interplay between MPs/NPs, mitochondrial dysfunction, and the aging process. We aspire that this article will enhance awareness regarding the toxicity of MPs/NPs while also offering a theoretical framework to support the development of improved regulatory policies in the future.

Mitochondria in aging and age-associated diseases

Mitochondria, essential for cellular energy, are crucial in neurodegenerative disorders (NDDs) and their age-related progression. This review highlights mitochondrial dynamics, mitovesicles, homeostasis, and organelle communication. We examine mitochondrial impacts from aging and NDDs, focusing on protein aggregation and dysfunction. Prospective therapeutic approaches include enhancing mitophagy, improving respiratory chain function, maintaining calcium and lipid balance, using microRNAs, and mitochondrial transfer to protect function. These strategies underscore the crucial role of mitochondrial health in neuronal survival and cognitive functions, offering new therapeutic opportunities.

Procyanidins inhibit alphacoronavirus infection by reducing interferon antagonism

BACKGROUND

The development of coronavirus drugs has primarily focused on targeting viral components, such as RNA-dependent RNA polymerase (RdRP), with relatively little attention given to enhancing host antiviral defenses. α-Coronaviruses, including human-infecting HCoV-NL63 and HCoV-229E, utilize immune evasion strategies such as suppressing host interferon production to establish infection. Procyanidins (PC), oligomeric compounds composed of catechin and epicatechin, have demonstrated the ability to stimulate host interferon synthesis, potentially counteracting this immune evasion. Exploring the inhibitory effects of PC specifically on α-coronaviruses offers a promising avenue for developing novel therapeutic strategies that bolster host immunity against these pathogens.

PURPOSE

This study aims to evaluate the inhibitory effects of PC on α-coronaviruses using different cell models and investigate whether its antiviral activity is linked to enhanced interferon production. By examining PC's effects on selected α-coronaviruses, this research explores its potential as a therapeutic strategy against human-infecting HCoV-NL63 and HCoV-229E, which evade innate immunity.

METHODS

Vero cells, human embryonic kidney 293T (HEK-293T) cells, and intestinal porcine epithelial-J2 (IPEC-J2) cells were used as cell models, with porcine epidemic diarrhea virus (PEDV) serving as the α-coronavirus infection model. The inhibitory effects of PC on the α-coronaviruses and its activation of interferon were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB). Co-immunoprecipitation (co-IP) was used to assess how PC impacts the degradation of Retinoic acid-inducible gene I (RIG-I) and TANK-binding kinase 1 (TBK1) by coronavirus N protein. Confocal microscopy was utilized to observe the recovery of mitochondrial morphology disrupted by coronavirus, and flow cytometry analyses were conducted.

RESULTS

Viral cycle and time-of-addition analyses showed that PC inhibited PEDV infection during both the replication and release stages of the virus. Simultaneously, in the early stages of infection, PC countered PEDV's evasion of interferon by elevating host interferon levels. Co-immunoprecipitation experiments confirmed that this effect was achieved by reducing the binding of coronavirus N protein to key proteins in the interferon synthesis pathway, RIG-I and TBK1, a mechanism previously identified as one of the main reasons for interferon evasion by α-coronavirus N protein. Additionally, intriguingly, we observed that PC has the ability to restore excessive mitochondrial fission induced by coronaviruses, an effect achieved by reducing the binding of coronavirus N protein to mitochondrial fusion protein 1 (MFN1). This observation suggests potential mechanistic pathways through which PC impacts mitochondrial antiviral-related proteins. These results suggest that PC may also inhibit human α-coronaviruses, such as HCoV-NL63 and HCoV-229E, by utilizing similar antiviral mechanisms. This provides valuable insights into potential therapeutic strategies for treating human coronaviruses.

CONCLUSIONS

These results suggest that PC may inhibit α-coronavirus infection by reversing the virus's antagonistic effects on interferon. These findings provide a new perspective for exploring therapeutic mechanisms against coronaviruses like HCoV-NL63, HCoV-229E, SARS-CoV-2, SARS-CoV, and MERS-CoV, which can evade host innate immunity, including the identification of new drug targets.

The carcinogenic metabolite acetaldehyde impairs cGAS activity to negatively regulate antiviral and antitumor immunity

The cGAS-MITA/STING pathway plays critical roles in both host defense against DNA virus and intrinsic antitumor immunity by sensing viral genomic DNA or dis-located mitochondrial/cellular DNA. Whether carcinogenic metabolites can target the cGAS-MITA axis to promote tumorigenesis is unknown. In this study, we identified acetaldehyde, a carcinogenic metabolite, as a suppressor of the cGAS-MITA pathway. Acetaldehyde inhibits the DNA virus herpes simplex virus 1 (HSV-1)- and transfected DNA-triggered but not cGAMP-induced activation of downstream components and induction of downstream effector genes. Mechanistically, acetaldehyde impairs the binding of cGAS to DNA as well as the phase separation of the cGAS-DNA complex in cells. In mouse models, acetaldehyde inhibits antiviral cytokine production, promotes viral replication and lethality upon HSV-1 infection. In a colorectal tumor xenograft model, acetaldehyde promotes tumor growth and inhibits CD8+ T cell infiltration by targeting cGAS in both the tumor cells and immune cells in mice. Bioinformatic analysis indicates that expression of acetaldehyde dehydrogenase 2 (ALDH2), which converts acetaldehyde to acetic acid, is negatively correlated with stimulatory immune signatures in clinical colorectal tumors, and higher ALDH2 expression exhibits better prognosis of colorectal cancer patients. Collectively, our results suggest that acetaldehyde impairs cGAS activity to inhibit the cGAS-MITA axis, which contributes to its effects on carcinogenesis.

Urolithin A alleviates radiation pneumonitis by activating PINK1/PRKN-mediated Mitophagy

BACKGROUND

Radiation pneumonitis (RP) is a common and severe complication of radiotherapy, whose pathogenesis involves complex inflammatory responses and cellular damage. Despite its clinical significance, effective treatments remain limited. This study investigates the role of radiation-induced PINK1/PRKN-mediated mitophagy and type I interferon responses in RP and evaluates the therapeutic potential of Urolithin A (UA) in regulating inflammation through mitophagy activation.

METHODS

We established RP mouse models (20 Gy thoracic irradiation) and radiation-induced BEAS-2B cell models (6 Gy). We systematically investigated mitochondrial damage, mtRNA release, RIG-I/MDA5-MAVS pathway activation, and PINK1/PRKN-mediated mitophagy changes. Moreover, the effects of UA and the mitophagy inhibitor Mdivi-1 on inflammation and lung injury were analyzed.

RESULTS

Radiation significantly caused mitochondrial damage in lung tissues, inducing mtRNA release and RIG-I/MDA5-MAVS-mediated type I interferon response. PINK1/PRKN-mediated mitophagy was significantly enhanced, clearing damaged mitochondria and reducing cytosolic mtRNA release, thereby suppressing inflammation. Pharmacological activation of mitophagy with UA markedly improved lung pathology, reduced inflammatory cytokine levels, and inhibited excessive activation of the RIG-I/MDA5-MAVS pathway. Conversely, the knockdown of PINK1 or PRKN weakened the protective effects of UA. Both in vitro and in vivo, UA reduced radiation-induced inflammation and improved lung tissue structure and function through mitophagy.

CONCLUSIONS

Radiation-induced mtRNA release activates the RIG-I/MDA5-MAVS-mediated type I interferon response, driving inflammation in RP. PINK1/PRKN-mediated mitophagy significantly alleviates inflammation by reducing cytosolic mtRNA release. As a mitophagy inducer, UA demonstrates therapeutic potential for RP, providing a new direction for the development of anti-inflammatory strategies.

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

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

The USP43/RNF2 axis negatively regulates antiviral innate immunity by promoting TBK1 ubiquitination and degradation

The E3 ubiquitin ligase usually regulates the substrate proteins ubiquitination and degradation, but the study of itself post-translational modification and stability is still elusive. Here, we reveal that E3 ubiquitin ligase ring finger protein 2 (RNF2) is deubiquitinated and stabilized by ubiquitin specific peptidase 43 (USP43) through interactome and quantitative ubiquitinome mass spectrometry analysis. This study demonstrated that USP43, as a deubiquitinating enzyme, negatively regulates the expression of type I interferon (IFN) and the Usp43 deficient enhances antiviral innate immune response against VSV infection both in vitro and in vivo. Mechanistically, USP43 negatively regulates antiviral immunity by promoting RNF2-mediated TBK1 ubiquitination and degradation. USP43 stabilizes RNF2 by removing K48-linked ubiquitination of RNF2 at Lys239 and Lys249, while RNF2 promotes TBK1 degradation by increasing K48-linked ubiquitination of TBK1 at Lys670. These findings uncover the E3 ubiquitin ligase RNF2 post-translational ubiquitination modification and stability regulation, and reveals a novel mechanism that the USP43/RNF2 axis in regulating antiviral innate immunity.

Mitochondrial DNA in Exercise-Mediated Innate Immune Responses

Mitochondria are considered as "the plant of power" with cells for a long time. However, recent researches suggest that mitochondria also take part in innate immune response to a great extent. Remarkably, mtDNA was reported to have immunnostimulatory potential in 2004. Since then, there has been rapid growth in understanding the role of mtDNA in innate immune. The mtDNA is released into cytosol, extracellular environment, or circulating blood through BAK/BAX pore, mPTP, and GSDMD pore upon mitochondrial damage, where it is recognized by PRRs including TLR9, cGAS, and NLRP3, thereby triggering innate immune response. On the other hand, regular exercise has been recognized as an effective intervention strategy for innate immune response. Some studies show that chronic moderate-intensity endurance exercise, resistance training, HIIT, and moderate-intensity acute exercise enhance mitochondrial function by promoting mtDNA transcription and replication, thus blunting the abnormal release of mtDNA and excessive innate immune response. On the contrary, high-intensity acute exercise elicits the opposite effect. Nevertheless, only a very small body of research by far has been performed to illustrate the impact of exercise on mtDNA-driven innate immune response, and an overall review is lacking. In light of these, we summarize the current knowledge on the mechanism mediating the release of mtDNA, the role of mtDNA in innate immune response and the influence of exercise on mtDNA leakage, hoping to pave the way to investigate new diagnostic and therapeutic approaches for immunopathies.

DNA-RNA hybrids in inflammation: sources, immune response, and therapeutic implications

Cytoplasmic DNA-RNA hybrids are emerging as important immunogenic nucleic acids, that were previously underappreciated. DNA-RNA hybrids, formed during cellular processes like transcription and replication, or by exogenous pathogens, are recognized by pattern recognition receptors (PRRs), including cGAS, DDX41, and TLR9, which trigger immune responses. Post-translational modifications (PTMs) including ubiquitination, phosphorylation, acetylation, and palmitoylation regulate the activity of PRRs and downstream signaling molecules, fine-tuning the immune response. Targeting enzymes involved in DNA-RNA hybrid metabolism and PTMs regulation offers therapeutic potential for inflammatory diseases. Herein, we discuss the sources, immune response, and therapeutic implications of DNA-RNA hybrids in inflammation, highlighting the significance of DNA-RNA hybrids as potential targets for the treatment of inflammation.

Multi-Omics Integration Reveals Mitochondrial Gene Regulation as a Determinant of Tuberculosis Susceptibility: A Mendelian Randomization Approach

Background/Objectives: Mitochondrial dysfunction has been implicated in the pathogenesis of tuberculosis (TB). Despite emerging evidence of the importance of mitochondrial gene regulation in the immune response, the specific role of mitochondrial-related genes in TB susceptibility remains to be fully elucidated. Methods: We employed a multi-omics approach integrating genetic, methylation, and protein-level data. Mendelian randomization (MR) and colocalization analyses were conducted to explore causal associations between mitochondrial gene features-expression quantitative trait loci (eQTL), methylation quantitative trait loci (mQTL), and protein quantitative trait loci (pQTL)-and TB susceptibility. Data were obtained from the FinnGen cohort and validated using independent datasets. Results: Our analyses identified several key mitochondrial genes (e.g., ACSF3, AK3, LYRM4, and PDHB) significantly associated with TB susceptibility. Random forest analysis and gene set enrichment analysis (GSEA) supported the predictive power of these genes. Furthermore, we observed significant correlations between mitochondrial gene expression and immune cell infiltration in TB patients, suggesting a role of these genes in modulating immune responses during infection. Receiver operating characteristic (ROC) analysis confirmed strong predictive accuracy for the identified feature genes, with area under the curve (AUC) values exceeding 0.7. Conclusions: This study demonstrates that mitochondrial-related gene regulation influences TB susceptibility across genetic, methylation, and protein levels. The integration of multi-omics data provides valuable insight into the molecular mechanisms underlying TB, highlighting the potential of mitochondrial genes as biomarkers and therapeutic targets.

HTLV-1 Tax induces PINK1-Parkin-dependent mitophagy to mitigate activation of the cGAS-STING pathway

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATLL) and the neuroinflammatory disease, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLV-1 Tax regulatory protein plays a critical role in HTLV-1 persistence and pathogenesis; however, the underlying mechanisms are poorly understood. Here we show that Tax dynamically regulates mitochondrial reactive oxygen species (ROS) and membrane potential to trigger mitochondrial dysfunction. Tax is recruited to damaged mitochondria through its interaction with the IKK regulatory subunit NEMO and directly engages the ubiquitin-dependent PINK1-Parkin pathway to induce mitophagy. Tax also recruits autophagy receptors NDP52 and p62/SQSTM1 to damaged mitochondria to induce mitophagy. Furthermore, Tax requires Parkin to limit the extent of cGAS-STING activation and suppress type I interferon (IFN). HTLV-1-transformed T cell lines and PBMCs from HAM/TSP patients exhibit hallmarks of chronic mitophagy which may contribute to immune evasion and pathogenesis. Collectively, our findings suggest that Tax manipulation of the PINK1-Parkin mitophagy pathway represents a new HTLV-1 immune evasion strategy.

Targeting cGAS-STING pathway for reprogramming tumor-associated macrophages to enhance anti-tumor immunotherapy

The cyclic GMP-AMP synthase (cGAS)-stimulator interferon genes (STING) signaling pathway plays a crucial role in activating innate and specific immunity in anti-tumor immunotherapy. As the major infiltrating cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) could be polarized into either anti-tumor M1 or pro-tumor M2 types based on various stimuli. Accordingly, targeted reprogramming TAMs to restore immune balance shows promise as an effective anti-tumor strategy. In this review, we aim to target cGAS-STING pathway for reprogramming TAMs to enhance anti-tumor immunotherapy. We investigated the double-edged sword effects of cGAS-STING in regulating TME. The regulative roles of cGAS-STING pathway in TAMs and its impact on the TME were further revealed. More importantly, several strategies of targeting cGAS-STING for reprogramming TAMs were designed for enhancing anti-tumor immunotherapy. Taken together, targeting cGAS-STING pathway for reprogramming TAMs in TME might be a promising strategy to enhance anti-tumor immunotherapy.

Role of Z-DNA Binding Protein 1 Sensing Mitochondrial Z-DNA and Triggering Necroptosis in Oxalate-Induced Acute Kidney Injury

Key Points

Gene deletions of Zbp1 , Ripk3 , and Mlkl reduced severity of oxalate-induced AKI. Mice with mutation or deletion in the Z-nucleic acid sensing domain (Zα ) of Z-DNA binding protein 1 were protected from AKI. Z-DNA binding protein 1 sensed mitochondrial Z-DNA through its Zα domain, recruited receptor-interacting protein kinase 3 through receptor-interacting protein homotypic interaction motif, and activated mixed lineage kinase domain-like to induce necroptosis.

Background

Calcium oxalate–induced acute kidney injury is a severe condition in which the kidneys suffer rapid damage due to the deposition of oxalate crystals. Known factors contributing to cell death induced by calcium oxalate include receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like (MLKL) protein–dependent necroptosis, as well as necrosis involving peptidylprolyl isomerase F–mediated mitochondrial permeability transition. However, the detailed molecular mechanisms linking mitochondrial dysfunction to RIPK3 activation are not fully understood.

Methods

Mice with gene knockout of Zbp1 , Ripk3 , or Mlkl and mice with mutations in the Z-nucleic acid sensing domain of Z-DNA binding protein 1 (ZBP1) or deletion of Zα 1 were used in an oxalate-induced AKI model. Proximal renal tubule cells were isolated and cultured for further investigation. Human oxalate nephropathy biopsy samples were analyzed.

Results

Specific gene deletions of Zbp1 , Ripk3 , or Mlkl in proximal renal tubules significantly reduced the severity of oxalate-induced AKI by preventing necroptosis and subsequent inflammation. Notably, mice with mutations in the Z-nucleic acid sensing domain of ZBP1 or deletion of Zα1 were protected from AKI. In cultured proximal tubular cells, calcium oxalate damaged mitochondria, accompanied by an increase in Bax and a decrease in BCL2 and transcription factor A, mitochondrial (TFAM), leading to the release of mitochondrial Z-DNA. ZBP1 sensed this mitochondrial Z-DNA and then recruited RIPK3 through the receptor-interacting protein homotypic interaction motifs, which in turn activated MLKL through RIPK3 phosphorylation, leading to necroptosis and contributing to AKI.

Conclusions

ZBP1 plays a critical role in sensing mitochondrial Z-DNA and initiating RIPK3/MLKL-mediated necroptosis, contributing to the development of oxalate-induced AKI.

Concurrent Amplification of Ferroptosis and Immune System Activation Via Nanomedicine-Mediated Radiosensitization for Triple-Negative Breast Cancer Therapy

Radiation therapy (RT) is one of the core therapies for current cancer management. However, the emergence of radioresistance has become a major cause of radiotherapy failure and disease progression. Therefore, overcoming radioresistance to achieve highly effective treatment for refractory tumors is significant yet challenging. Here, pH-responsive DSPE-PEoz modified hollow Bi2Se3-RSL3/diABZi (DP-HBN/RA) nanomedicine is designed as a radiation sensitizer for efficient treatment of triple-negative breast cancer by simultaneously amplifying ferroptosis and immune system activation. DP-HBN/RA can efficiently concentrate X-ray radiation energy inside the tumor, thereby promoting precise ionizing radiation exposure in tumor cells to produce large amounts of reactive oxygen species (ROS), leading to lipid peroxidation-induced ferroptosis. Meanwhile, ferroptotic cell death is intensified through the inactivation of GPX4 by RSL3 released from DP-HBN/RA to acidic conditions in the tumor microenvironment. Additionally, DP-HBN/RA enhances RT efficacy to exacerbate unrepairable DNA damage and release DNA fragments that activate the cGAS-STING signal pathway, evoking a systematic immune response. Ingeniously, the released diABZi reinforces cGAS-STING activation to boost the immunology antitumor effect. This work links the induction of ferroptosis and the initiation of systematic immune response to achieve highly effective tumor suppression, which opens up new avenues for future treatments of refractory tumors.

Mitochondrial DNA-activated cGAS-STING pathway in cancer: Mechanisms and therapeutic implications

Mitochondrial DNA (mtDNA), a circular double-stranded DNA located within mitochondria, plays a pivotal role in mitochondrial-induced innate immunity, particularly via the cyclic GMP-AMP synthase (cGAS)-STING pathway, which recognizes double-stranded DNA and is crucial for pathogen resistance. Recent studies elucidate the interplay among mtDNA, the cGAS-STING pathway, and neutrophil extracellular traps (NETs) in the context of cancer. mtDNA uptake by recipient cells activates the cGAS-STING pathway, while mtDNA leakage reciprocally regulates NET release, amplifying inflammation and promoting NETosis, a mechanism of tumor cell death. Autophagy modulates these processes by clearing damaged mitochondria and degrading cGAS, thus preventing mtDNA recognition. Tumor microenvironmental factors, such as metabolic reprogramming and lipid accumulation, induce mitochondrial stress, ROS production, and further mtDNA leakage. This review explores strategies in cancer drug development that leverage mtDNA leakage to activate the cGAS-STING pathway, potentially converting 'cold tumors' into 'hot tumors,' while discussing advancements in targeted therapies and proposing new research methodologies.

Cellular takeover: How new world alphaviruses impact host organelle function

Alphavirus replication is dependent on host cell organelles to facilitate multiple steps of the viral life cycle. New world alphaviruses (NWA) consisting of eastern, western and Venezuelan equine encephalitis viruses are a subgroup of alphaviruses associated with central nervous system disease. Despite differing morbidity and mortality amongst these viruses, all are important human pathogens due to their transmission through viral aerosolization and mosquito transmission. In this review, we summarize the utilization of host organelles for NWA replication and the subversion of the host innate immune responses. The impact of viral proteins and replication processes on organelle function is also discussed. Literature involving old world alphaviruses (OWA), such as chikungunya virus and Sindbis virus, is included to compare and contrast between OWA and NWA and highlight gaps in knowledge for NWA. Finally, potential targets for therapeutics or vaccine candidates are highlighted with a focus on host-directed therapeutics.

Associations between prenatal distress, mitochondrial health, and gestational age: findings from two pregnancy studies in the USA and Turkey

Objective

This study examined associations between mitochondrial markers-circulating cell-free mitochondrial DNA (cf-mtDNA) and Growth Differentiation Factor-15 (GDF15)-with maternal distress and pregnancy outcomes.

Method

Participants were drawn from two pregnancy studies, EPI (N=187, USA) and BABIP (N=198, Turkey). Plasma cf-mtDNA and GDF15 levels were quantified using qPCR and ELISA assays.

Results

Plasma cf-mtDNA levels did not significantly vary across pregnancy, while plasma GDF15 levels increased from early to late pregnancy and decreased postpartum. Late 2nd trimester plasma GDF15 was negatively correlated with pre-pregnancy BMI (p=0.035) and gestational age (p=0.0048) at birth. Early 2nd trimester maternal distress was associated with lower cf-mtDNA (p<0.05) and a trend for lower GDF15. Higher pre-pregnancy BMI and late-pregnancy maternal distress were linked to smaller postpartum GDF15 declines in EPI (p<0.05).

Conclusion

This study reveals distinct plasma cf-mtDNA and GDF15 patterns during the perinatal period, linking mitochondrial markers to maternal distress and pregnancy outcomes.

A new paradigm for cancer immunotherapy: targeting immunogenic cell death-related noncoding RNA

Cancer immunotherapy has shown significant potential in treating several malignancies by stimulating the host immune system to recognize and attack cancer cells. Immunogenic cell death (ICD) can amplify the antitumor immune responses and reverse the immunosuppressive tumor microenvironment, thus increasing the sensitivity of cancer immunotherapy. In recent years, noncoding RNAs (ncRNAs) have emerged as key regulatory factors in ICD and oncologic immunity. Accordingly, ICD-related ncRNAs hold promise as novel therapeutic targets for optimizing the efficacy of cancer immunotherapy. However, the immunomodulatory properties of ICD-related ncRNAs have not yet been comprehensively summarized. Hence, we summarize the current knowledge on ncRNAs involved in ICD and their potential roles in cancer immunotherapy in this review. It deepens our understanding of ncRNAs associated with ICD and provides a new strategy to enhance cancer immunotherapy by specifically targeting the ICD-related ncRNAs.

Hovenia dulcis Thunb. Honey Exerts Antiviral Effect Against Influenza A Virus Infection Through Mitochondrial Stress-Mediated Enhancement of Innate Immunity

To combat influenza A virus (IAV) infection, it is vital to develop effective therapeutic strategies, including immunomodulators. In this study, we examined the antiviral effects of Hovenia dulcis Thunb. honey (HDH) against IAV using RAW 264.7 cells. HDH treatment significantly reduced IAV infection and viral protein expression. Moreover, it enhanced the production of interferon (IFN)-β, activated the innate immune response through the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, and upregulated IFN signaling through signal transducer and activator of transcription (STAT)1/2 phosphorylation and interferon-stimulated gene (ISG) expression. In addition, HDH decreased IAV-induced intracellular and mitochondrial reactive oxygen species (ROS) production by upregulating the expression of antioxidant proteins, such as Sirt3 and SOD2. The results suggest that HDH is a potential therapeutic agent inhibiting viral replication and boosting host antiviral immunity.

Safety and efficacy of mesenchymal stromal cells mitochondria transplantation as a cell-free therapy for osteoarthritis

OBJECTIVE

The inflammatory responses from synovial fibroblasts and macrophages and the mitochondrial dysfunction in chondrocytes lead to oxidative stress, disrupt extracellular matrix (ECM) homeostasis, and accelerate the deterioration process of articular cartilage in osteoarthritis (OA). In recent years, it has been proposed that mesenchymal stromal cells (MSC) transfer their functional mitochondria to damaged cells in response to cellular stress, becoming one of the mechanisms underpinning their therapeutic effects. Therefore, we hypothesize that a novel cell-free treatment for OA could involve direct mitochondria transplantation, restoring both cellular and mitochondrial homeostasis.

METHODS

Mitochondria were isolated from Umbilical Cord (UC)-MSC (Mito-MSC) and characterized based on their morphology, phenotype, functions, and their ability to be internalized by different articular cells. Furthermore, the transcriptional changes following mitochondrial uptake by chondrocytes were evaluated using an Affymetrix analysis, Lastly, the dose dependence therapeutic efficacy, biodistribution and immunogenicity of Mito-MSC were assessed in vivo, through an intra-articular injection in male C57BL6 mice in a collagenase-induced OA (CIOA) model.

RESULTS

Our findings demonstrate the functional integrity of Mito-MSC and their ability to be efficiently transferred into chondrocytes, synovial macrophages, and synovial fibroblasts. Moreover, the transcriptomic analysis showed the upregulation of genes involved in stress such as DNA reparative machinery and inflammatory antiviral responses. Finally, Mito-MSC transplantation yielded significant reductions in joint mineralization, a hallmark of OA progression, as well as improvements in OA-related histological signs, with the lower dose exhibiting better therapeutic efficacy. Furthermore, Mito-MSC was detected within the knee joint for up to 24 h post-injection without eliciting an inflammatory response in CIOA mice.

CONCLUSION

Collectively, our results reveal that mitochondria derived from MSC are transferred to key articular cells and are retained in the joint without generating an inflammatory immune response mitigating articular cartilage degradation in OA, probably through a restorative effect triggered by the stress antiviral response within OA chondrocytes.

Chronic Low-Level IFN-γ Expression Disrupts Mitochondrial Complex I Activity in Renal Macrophages: An Early Mechanistic Driver of Lupus Nephritis Pathogenesis

Mitochondrial dysfunction and macrophage dysregulation are well recognized as significant contributors to the pathogenesis of autoimmune diseases. However, the detailed mechanisms connecting these two factors remain poorly understood. This study hypothesizes that low but chronic interferon-gamma (IFN-γ) plays a critical role in these processes. To explore this, we utilized ARE-Del mice, a model characterized by sustained low-level IFN-γ expression and lupus nephritis (LN)-like symptoms. Age- and tissue-dependent gene expression analyses in ARE-Del mice revealed significant suppression of mitochondrial complex I components and activities, particularly in the kidneys. The genotype-dependent suppression of mitochondrial complex I indicates early disruption, which leads to macrophage dysfunction. Notably, remission restored gene expression of mitochondrial complex I and macrophage dysfunction in isolated renal macrophages from NZB/W lupus-prone mice. These findings suggest that chronic low-level IFN-γ disrupts mitochondrial complex I activity in macrophages, highlighting its role in the early pathogenesis of autoimmune diseases like lupus nephritis. This provides new insights into the molecular interactions underlying autoimmune pathogenesis and suggests potential targets for therapeutic intervention.

Zinc-based radioenhancers to activate tumor radioimmunotherapy by PD-L1 and cGAS-STING pathway

Radiotherapy and immunotherapy have already become the primary form of treatment for non-small-cell lung cancer (NSCLC), but are limited by high radiotherapy dose and low immune response rate. Herein, a multi-pronged strategy using a radio-immuno-enhancer (ZnO-Au@mSiO2) is developed by inducing tumor cells apoptosis and reprograming the immunosuppressive tumor microenvironment (TME). The radio-immuno-enhancer employed Au as a radiosensitizer, transition Zn ions as immune activators, which not only tremendously enhances the anti-proliferative activity of radiotherapy toward cancer cells, but also activates the immune response with multi-targets to let "exhausted" T cells "back to life" by triggering immunogenic cell death (ICD), immune checkpoint blockade (ICB) that target PD-1/PD-L1 and cGAS-STING under X-ray irradiation with a low dosage. The in vivo results demonstrate desirable antitumor and immunogenic effects of radio-immuno-enhancer-mediated immune activation by increasing the ratio of cytotoxic T cells (CTLs) and helper T cells. This work provides a feasible approach for future development of effective transition metal ion-activated radio-immunotherapeutic agents.

Mitochondrial DNA copy number and the risk of autoimmune diseases: A Mendelian randomization study with meta-analysis

Background

Mitochondrial DNA plays a crucial role in the pathophysiology of autoimmune diseases (ADs). However, the association between mitochondrial DNA copy number (mtDNA-CN) and ADs risk is controversial. In this study, Mendelian randomization (MR) analysis and meta-analysis were performed using three sets of independent instrumental variables (IVs) to investigate the potential association between mtDNA-CN and 20 types of ADs.

Methods

The three sets of IVs were drawn primarily from participants in the UK Biobank and the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium using different methods. Outcome data for ADs were investigated using summary statistics from the FinnGen cohort. The potential causal associations were assessed using inverse-variance weighting (IVW), MR-Egger, and weighted median methods. Sensitivity analysis and the Steiger test were used to verify the robustness of the MR estimates. In addition, a meta-analysis was conducted to pool the results from three IV groups.

Results

Overall, genetically predicted mtDNA-CN was not associated with ADs risk (OR = 1.046, 95 % CI: 0.964-1.135, P = 0.283). However, subgroup analyses showed positive causal associations of mtDNA-CN with autoimmune hypothyroidism (OR = 1.133, 95 % CI: 1.016-1.262, P = 0.024) and rheumatoid arthritis (OR = 1.219, 95 % CI: 1.028-1.445, P = 0.023). In contrast, there was no causal association between mtDNA-CN and atopic dermatitis as well as psoriasis, ulcerative colitis, adult-onset Still disease, type1 diabetes, Crohn disease, sarcoidosis, ankylosing spondylitis, multiple sclerosis, autoimmune hyperthyroidism, primary sclerosing cholangitis, systemic lupus erythematosus, systemic sclerosis, alopecia areata, myasthenia gravis, Guillain-Barre syndrome, dermatopolymyositis, and vitiligo.

Conclusions

This MR analysis showed mtDNA-CN is causally associated with an increased risk of autoimmune hypothyroidism and rheumatoid arthritis at the genetic level. The findings have important implications for the use of mtDNA-CN as a biomarker for risk assessment of autoimmune hypothyroidism and rheumatoid arthritis in clinical practice.

Microglial mitochondrial DNA release contributes to neuroinflammation after intracerebral hemorrhage through activating AIM2 inflammasome

Intracerebral hemorrhage (ICH) is a severe disease that often leads to disability and death. Neuroinflammatory response is a key causative factor of early secondary brain injury after ICH. AIM2 is a DNA-sensing protein that recognizes cytosolic double-stranded DNA and take a significant part in neuroinflammation. Mitochondrial DNA participates in the translation of proteins such as the respiratory chain in the mitochondria. Whether mtDNA is involved in forming AIM2 inflammasome after ICH remains unclear. We used mice to construct ICH model in vivo and we used BV2 microglial cells treated with oxyhemoglobin to simulate ICH in vitro. Following lentiviral transfection to overexpress AIM2 antagonist P202, a notable decrease was observed in the levels of AIM2 inflammasome-associated proteins, leading to a reduction in dead neurons surrounding the hematoma and an enhancement in long-term and short-term behavior of neurological deficits. We further explored whether mtDNA took part in the AIM2 activation after ICH. The cytosolic mtDNA level was down-regulated by the mitochondrial division protector Mdivi-1 and up-regulated by transfection of mtDNA into cytoplasm. We found the expression level of AIM2 inflammasome-related proteins and inflammatory cytokines release were regulated by the cytosolic mtDNA level. In conclusion, after ICH, the mtDNA content in the cytoplasm of microglia around the hematoma rises, causing AIM2 inflammation leading to neuronal apoptosis, which leads to neurological deficits in mice. On the other hand, P202 was able to block inflammatory vesicle activation and improve neurological function by preventing the interaction between AIM2 protein and mitochondrial DNA.

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.

Mitochondrial Dysfunction and Cognitive Impairment in Schizophrenia: The Role of Inflammation

BACKGROUND AND HYPOTHESIS

The complex immune-brain interactions and the regulatory role of mitochondria in the immune response suggest that mitochondrial damage reported in schizophrenia (SZ) may be related to abnormalities observed in immune and brain functions.

STUDY DESIGN

Mitochondrial DNA copy number (mtDNA CN), a biomarker of mitochondrial function, was assessed in peripheral blood leukocytes (PBLs) of 121 healthy individuals and 118 SZ patients before and after 8 weeks of antipsychotic treatment, and a meta-analysis related to blood mtDNA CN was conducted. Plasma C-reactive protein (CRP) levels in SZ patients were obtained from the medical record system. Spearman correlation analysis and hierarchical linear regression were used to analyze the relationships among mtDNA CN, CRP levels, and cognitive function. A mediation model was constructed using the PROCESS program.

STUDY RESULTS

Our results revealed the decreased mtDNA CN in PBLs from SZ patients (P = .05). The meta-analysis supported the decreased blood mtDNA CN in SZ patients (P < .01). The mtDNA CN in PBL was positively correlated with working memory (P = .02) and negatively correlated with plasma CRP levels (P = .039). Furthermore, a lower mtDNA CN in PBL in SZ patients was a significant predictor of worse working memory (P = .006). CRP acted as a mediator with an 8.0% effect.

CONCLUSIONS

This study revealed an association between peripheral mitochondrial dysfunction and cognitive impairment in SZ, with inflammation acting as a mediating effect. Therefore, mitochondrial dysfunction might provide novel targets for new treatments for cognitive impairment in SZ.

Bendamustine-rituximab elicits dual tumoricidal and immunomodulatory responses via cGAS-STING activation in diffuse large B-cell lymphoma

BACKGROUND

Bendamustine-rituximab (BR) therapy stands out as a promising alternative for elderly patients with diffuse large B-cell lymphoma (DLBCL), demonstrating notable efficacy when conventional regimens pose challenges. Despite its clinical success, the intricate mechanisms underlying BR therapy have remained elusive.

METHODS

DLBCL cell lines were used to investigate the mechanism of BR therapy in vitro. RNA-seq and Western blot were used to explore the target pathways of BR therapy. STING was knocked out using Crispr-cas9 and inhibited using H-151 to investigate its role in BR therapy. Bulk RNA-seq and single-cell RNA-seq data from patients were analyzed to investigate the association between STING and pyroptosis pathways, validated using STING downregulated cells. Flow cytometry, transwell experiments and co-culture experiments were performed to investigate the inflammatory phenotype of DLBCL cells after BR treatment and its effect on T-cell recruitment and activation.

RESULTS

This study elucidates that BR elicits direct tumoricidal effects by promoting apoptosis and inducing cell cycle arrest. The synergistic impact with rituximab is further potentiated by complement addition, demonstrating the pivotal role of in vivo antibody-dependent cellular cytotoxicity. Moreover, our investigation reveals that, through a cGAS-STING-dependent pathway, prolonged exposure to BR induces pyroptosis in DLBCL cells. Activation of the cGAS-STING pathway by BR therapy triggers the release of inflammatory factors and upregulates major histocompatibility complex molecules, shaping an immunologically hot tumor microenvironment.

CONCLUSIONS

This unique dual influence not only directly targets DLBCL cells but also engages the patient's immune system, paving the way for innovative combination therapies. The study provides comprehensive insights into the multifaceted actions of BR in DLBCL, offering a foundation for refined and personalized treatment strategies in elderly patients.

The cGAS-STING pathway drives neuroinflammation and neurodegeneration via cellular and molecular mechanisms in neurodegenerative diseases

Neurodegenerative diseases (NDs) are a type of common chronic progressive disorders characterized by progressive damage to specific cell populations in the nervous system, ultimately leading to disability or death. Effective treatments for these diseases are still lacking, due to a limited understanding of their pathogeneses, which involve multiple cellular and molecular pathways. The triggering of an immune response is a common feature in neurodegenerative disorders. A critical challenge is the intricate interplay between neuroinflammation, neurodegeneration, and immune responses, which are not yet fully characterized. In recent years, the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) pathway, a crucial immune response for intracellular DNA sensing, has gradually gained attention. However, the specific roles of this pathway within cellular types such as immune cells, glial and neuronal cells, and its contribution to ND pathogenesis, remain not fully elucidated. In this review, we systematically explore how the cGAS-STING signaling links various cell types with related cellular effector pathways under the context of NDs for multifaceted therapeutic directions. We emphasize the discovery of condition-dependent cellular heterogeneity in the cGAS-STING pathway, which is integral for understanding the diverse cellular responses and potential therapeutic targets. Additionally, we review the pathogenic role of cGAS-STING activation in Parkinson's disease, ataxia-telangiectasia, and amyotrophic lateral sclerosis. We focus on the complex bidirectional roles of the cGAS-STING pathway in Alzheimer's disease, Huntington's disease, and multiple sclerosis, revealing their double-edged nature in disease progression. The objective of this review is to elucidate the pivotal role of the cGAS-STING pathway in ND pathogenesis and catalyze new insights for facilitating the development of novel therapeutic strategies.

High mitochondrial DNA levels accelerate lung adenocarcinoma progression

Lung adenocarcinoma is a common aggressive cancer and a leading cause of mortality worldwide. Here, we report an important in vivo role for mitochondrial DNA (mtDNA) copy number during lung adenocarcinoma progression in the mouse. We found that lung tumors induced by KRASG12D expression have increased mtDNA levels and enhanced mitochondrial respiration. To experimentally assess a possible causative role in tumor progression, we induced lung cancer in transgenic mice with a general increase in mtDNA copy number and found that they developed a larger tumor burden, whereas mtDNA depletion in tumor cells reduced tumor growth. Immune cell populations in the lung and cytokine levels in plasma were not affected by increased mtDNA levels. Analyses of large cancer databases indicate that mtDNA copy number is also important in human lung cancer. Our study thus reports experimental evidence for a tumor-intrinsic causative role for mtDNA in lung cancer progression, which could be exploited for development of future cancer therapies.

The role of the cGAS-STING pathway in chronic pulmonary inflammatory diseases

The innate immune system plays a vital role in the inflammatory process, serving as a crucial mechanism for the body to respond to infection, cellular stress, and tissue damage. The cGAS-STING signaling pathway is pivotal in the onset and progression of various autoimmune diseases and chronic inflammation. By recognizing cytoplasmic DNA, this pathway initiates and regulates inflammation and antiviral responses within the innate immune system. Consequently, the regulation of the cGAS-STING pathway has become a prominent area of interest in the treatment of many diseases. Chronic inflammatory lung diseases, such as chronic obstructive pulmonary disease (COPD), asthma, and pulmonary fibrosis, are characterized by persistent or recurrent lung inflammation and tissue damage, leading to diminished respiratory function. This paper explores the mechanism of action of the cGAS-STING signaling pathway in these diseases, examines the development of STING inhibitors and nanomaterial applications, and discusses the potential clinical application prospects of targeting the cGAS-STING pathway in chronic inflammatory lung diseases.

Viruses and Mitochondrial Dysfunction in Neurodegeneration and Cognition: An Evolutionary Perspective

Mitochondria, the cellular powerhouses with bacterial evolutionary origins, play a pivotal role in maintaining neuronal function and cognitive health. Several viruses have developed sophisticated mechanisms to target and disrupt mitochondrial function which contribute to cognitive decline and neurodegeneration. The interplay between viruses and mitochondria might be traced to their co-evolutionary history with bacteria and may reflect ancient interactions that have shaped modern mitochondrial biology.

The role of mitochondrial DNA copy number in autoimmune disease: a bidirectional two sample mendelian randomization study

Background

Mitochondrial DNA (mtDNA) plays an important role in autoimmune diseases (AD), yet the relationship between mitochondria and autoimmune disease is controversial. This study employed bidirectional Mendelian randomization (MR) to explore the causal relationship between mtDNA copy number and 13 ADs (including ankylosing spondylitis [AS], Crohn's disease [CD], juvenile rheumatoid arthritis [JRA], polymyalgia rheumatica [PMR], psoriasis [PSO], rheumatoid arthritis [RA], Sjogren's syndrome [SS], systemic lupus erythematosus [SLE], thyrotoxicosis, type 1 diabetes mellitus [T1DM], ulcerative colitis [UC], and vitiligo).

Methods

A two-sample MR analysis was performed to assess the causal relationship between mtDNA copy number and AD. Genome-wide association study (GWAS) for mtDNA copy number were obtained from the UK Biobank (UKBB), while those associated with AD were sourced from the FinnGen Biobank. Inverse variance weighting (IVW) was the primary analysis method, complemented by three sensitivity analyses (MR-Egger, weighted median, weighted mode) to validate the results.

Results

IVW MR analysis identified significant associations between mtDNA copy number and CD (OR=2.51, 95% CI 1.56-4.22, P<0.001), JRA (OR=1.87, 95% CI 1.17-7.65, P=0.022), RA (OR=1.71, 95%CI 1.18-2.47, P=0.004), thyrotoxicosis (OR=0.51, 95% CI0.27-0.96, P=0.038), and T1DM (OR=0.51, 95% CI 0.27-0.96, P=0.038). Sensitivity analyses indicated no horizontal pleiotropy.

Conclusions

Our study revealed a potential causal relationship between mtDNA copy number and ADs, indicating that these markers may be relevant in exploring new therapeutic approaches.

Flaviviruses manipulate mitochondrial processes to evade the innate immune response

Mitochondria are essential eukaryotic organelles that regulate a range of cellular processes, from metabolism to calcium homeostasis and programmed cell death. They serve as essential platforms for antiviral signaling proteins during the innate immune response to viral infections. Mitochondria are dynamic structures, undergoing frequent fusion and fission processes that regulate various aspects of mitochondrial biology, including innate immunity. Pathogens have evolved sophisticated mechanisms to manipulate mitochondrial morphology and function to facilitate their replication. In this review, we examine the emerging literature on how flaviviruses modulate mitochondrial processes.

STING Promotes the Progression of ADPKD by Regulating Mitochondrial Function, Inflammation, Fibrosis, and Apoptosis

Autosomal dominant polycystic kidney disease (ADPKD) is a predominant genetic disease, which is caused by mutations in PKD genes and is associated with DNA damage in cystic cells. The intrinsic stimulator of interferon genes (STING) pathway is crucial for recognizing damaged DNA in the cytosol, triggering the expression of inflammatory cytokines to activate defense mechanisms. However, the precise roles and mechanisms of STING in ADPKD remain elusive. In this study, we show that Pkd1 mutant mouse kidneys show upregulation of STING, which is stimulated by the DNAs of nuclear and mitochondrial origin. The activation of STING promotes cyst growth through increasing (1) the activation of NF-κB in Pkd1 mutant cells and (2) the recruitment of macrophages in the interstitial and peri-cystic regions in Pkd1 mutant mouse kidneys via NF-κB mediating the upregulation of TNF-α and MCP-1. Targeting STING with its specific inhibitor C-176 delays cyst growth in an early-stage aggressive Pkd1 conditional knockout mouse model and a milder long-lasting Pkd1 mutant mouse model. Targeting STING normalizes mitochondrial structure and function, decreases the formation of micronuclei, induces Pkd1 mutant renal epithelial cell death via p53 signaling, and decreases renal fibrosis in Pkd1 mutant mouse kidneys. These results support that STING is a novel therapeutic target for ADPKD treatment.

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.

Self-assembly of a ruthenium-based cGAS-STING photoactivator for carrier-free cancer immunotherapy

The cGAS (cyclic GMP-AMP synthase)-STING (stimulator of interferon genes) pathway promotes antitumor immune responses by sensing cytosolic DNA fragments leaked from nucleus and mitochondria. Herein, we designed a highly charged ruthenium photosensitizer (Ru1) with a β-carboline alkaloid derivative as the ligand for photo-activating of the cGAS-STING pathway. Due to the formation of multiple non-covalent intermolecular interactions, Ru1 can self-assemble into carrier-free nanoparticles (NPs). By incorporating the triphenylphosphine substituents, Ru1 can target and photo-damage mitochondrial DNA (mtDNA) to cause the cytoplasmic DNA leakage to activate the cGAS-STING pathway. Finally, Ru1 NPs show potent antitumor effects and elicit intense immune responses in vivo. In conclusion, we report the first self-assembling mtDNA-targeted photosensitizer, which can effectively activate the cGAS-STING pathway, thus providing innovations for the design of new photo-immunotherapeutic agents.

Activation of the cGAS-STING-IRF3 Axis by Type I and II Interferons Contributes to Host Defense

Interferons (IFNs) activate JAK-STAT pathways to induce downstream effector genes for host defense against invaded pathogens and tumors. Here both type I (β) and II (γ) IFNs are shown that can activate the transcription factor IRF3 in parallel with STAT1. IRF3-deficiency impairs transcription of a subset of downstream effector genes induced by IFN-β and IFN-γ. Mechanistically, IFN-induced activation of IRF3 is dependent on the cGAS-STING-TBK1 axis. Both IFN-β and IFN-γ cause mitochondrial DNA release into the cytosol. In addition, IFNs induce JAK1-mediated tyrosine phosphorylation of cGAS at Y214/Y215, which is essential for its DNA binding activity and signaling. Furthermore, deficiency of cGAS, STING, or IRF3 impairs IFN-β- or IFN-γ-mediated antiviral and antitumor activities. The findings reveal a novel IRF3 activation pathway parallel with the canonical STAT1/2 activation pathways triggered by IFNs and provide an explanation for the pleiotropic roles of the cGAS-STING-IRF3 axis in host defense.

Personalised medicine in juvenile dermatomyositis: From novel insights in disease mechanisms to changes in clinical practice

Juvenile dermatomyositis is characterized by childhood-onset chronic inflammation of the muscles and skin, with potential involvement of other organs. Patients are at risk for long-term morbidity due to insufficient disease control and steroid-related toxicity. Personalised treatment is challenged by a lack of validated tools that can reliably predict treatment response and monitor ongoing (subclinical) inflammation, and by a lack of evidence regarding the best choice of medication for individual patients. A better understanding of the involved disease mechanisms could reveal potential biomarkers and novel therapeutic targets. In this review, we highlight the most relevant immune and non-immune mechanisms, elucidating the effects of interferon overexpression on tissue alongside the interplay between the interferon signature, mitochondrial function, and immune cells. We review mechanism-based biomarkers that are promising for clinical implementation, and the latest advances in targeted therapy development. Finally, we discuss key steps needed for translating these discoveries into clinical practice.

Post-Acute Sequelae and Mitochondrial Aberration in SARS-CoV-2 Infection

This review investigates links between post-acute sequelae of SARS-CoV-2 infection (PASC), post-infection viral persistence, mitochondrial involvement and aberrant innate immune response and cellular metabolism during SARS-CoV-2 infection. Advancement of proteomic and metabolomic studies now allows deeper investigation of alterations to cellular metabolism, autophagic processes and mitochondrial dysfunction caused by SARS-CoV-2 infection, while computational biology and machine learning have advanced methodologies of predicting virus-host gene and protein interactions. Particular focus is given to the interaction between viral genes and proteins with mitochondrial function and that of the innate immune system. Finally, the authors hypothesise that viral persistence may be a function of mitochondrial involvement in the sequestration of viral genetic material. While further work is necessary to understand the mechanisms definitively, a number of studies now point to the resolution of questions regarding the pathogenesis of PASC.

A nomogram prediction of coronary artery dilation in Kawasaki diseases based on mtDNA copy number

Objective

The level of mitochondrial DNA copy number (mtDNA-CN) in peripheral blood cells had been identified to be involved in several immune and cardiovascular diseases. Thus, the aim of this study is to evaluate the levels of mtDNA-CN in Kawasaki disease (KD) and to construct a nomogram prediction for coronary artery lesions in children with KD.

Methods

One hundred and forty-four children with KD diagnosed from March 2020 to March 2022 were involved in the study. The clinical features and laboratory test parameters of these children were assessed between the KD and normal groups. Univariable and multivariable analyses were performed sequentially to identify the essential risk factors. Subsequently, a nomogram prediction was constructed.

Results

A total of 274 children were included in the analysis. Of these, 144 (52.6%) represented the KD group. Peripheral blood DNA mtDNA qPCR showed that the -log value of mtDNA-CN in the KD group (6.67 ± 0.34) was significantly higher than that in the healthy group (6.40 ± 0.18) (P<0.001). The area under the ROC curve for mtDNA-CN in distinguishing KD was 0.757. MtDNA-CN (OR = 13.203, P = 0.009, 95% CI 1.888-92.305), RBC (OR = 5.135, P = 0.014, 95% CI 1.394-18.919), and PA (OR = 0.959, P = 0.014, 95% CI 0.927-0.991) were identified as independent risk factors for coronary artery dilation in children with KD. Finally, the nomogram predictive was established based on the results of multivariable analysis, demonstrating the satisfied prediction and calibration values.

Conclusion

The results of this study revealed that mtDNA-CN could be used as a biomarker in predicting the development of KD. Furthermore, the higher the mtDNA-CN was significantly associated with coronary artery dilation in KD.

SLE: a cognitive step forward-a synthesis of rethinking theories, causality, and ignored DNA structures

Systemic lupus erythematosus (SLE) is classified by instinctual classification criteria. A valid proclamation is that these formally accepted SLE classification criteria legitimate the syndrome as being difficult to explain and therefore enigmatic. SLE involves scientific problems linked to etiological factors and criteria. Our insufficient understanding of the clinical condition uniformly denoted SLE depends on the still open question of whether SLE is, according to classification criteria, a well-defined one disease entity or represents a variety of overlapping indistinct syndromes. Without rational hypotheses, these problems harm clear definition(s) of the syndrome. Why SLE is not anchored in logic, consequent, downstream interdependent and interactive inflammatory networks may rely on ignored predictive causality principles. Authoritative classification criteria do not reflect consequent causality criteria and do not unify characterization principles such as diagnostic criteria. We need now to reconcile legendary scientific achievements to concretize the delimitation of what SLE really is. Not all classified SLE syndromes are "genuine SLE"; many are theoretically "SLE-like non-SLE" syndromes. In this study, progressive theories imply imperative challenges to reconsider the fundamental impact of "the causality principle". This may offer us logic classification and diagnostic criteria aimed at identifying concise SLE syndromes as research objects. Can a systems science approach solve this problem?

The role of mitochondrial damage-associated molecular patterns in acute pancreatitis

Acute pancreatitis (AP) is one of the most common gastrointestinal tract diseases with significant morbidity and mortality. Current treatments remain unspecific and supportive due to the severity and clinical course of AP, which can fluctuate rapidly and unpredictably. Mitochondria, cellular power plant to produce energy, are involved in a variety of physiological or pathological activities in human body. There is a growing evidence indicating that mitochondria damage-associated molecular patterns (mtDAMPs) play an important role in pathogenesis and progression of AP. With the pro-inflammatory properties, released mtDAMPs may damage pancreatic cells by binding with receptors, activating downstream molecules and releasing inflammatory factors. This review focuses on the possible interaction between AP and mtDAMPs, which include cytochrome c (Cyt c), mitochondrial transcription factor A (TFAM), mitochondrial DNA (mtDNA), cardiolipin (CL), adenosine triphosphate (ATP) and succinate, with focus on experimental research and potential therapeutic targets in clinical practice. Preventing or diminishing the release of mtDAMPs or targeting the mtDAMPs receptors might have a role in AP progression.

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.

Arsenic trioxide augments immunogenic cell death and induces cGAS-STING-IFN pathway activation in hepatocellular carcinoma

The treatment of hepatocellular carcinoma (HCC) is particularly challenging due to the inherent tumoral heterogeneity and easy resistance towards chemotherapy and immunotherapy. Arsenic trioxide (ATO) has emerged as a cytotoxic agent effective for treating solid tumors, including advanced HCC. However, its effectiveness in HCC treatment remains limited, and the underlying mechanisms are still uncertain. Therefore, this study aimed to characterize the effects and mechanisms of ATO in HCC. By evaluating the susceptibilities of human and murine HCC cell lines to ATO treatment, we discovered that HCC cells exhibited a range of sensitivity to ATO treatment, highlighting their inherent heterogeneity. A gene signature comprising 265 genes was identified to distinguish ATO-sensitive from ATO-insensitive cells. According to this signature, HCC patients have also been classified and exhibited differential features of ATO response. Our results showed that ATO treatment induced reactive oxygen species (ROS) accumulation and the activation of multiple cell death modalities, including necroptosis and ferroptosis, in ATO-sensitive HCC cells. Meanwhile, elevated tumoral immunogenicity was also observed in ATO-sensitive HCC cells. Similar effects were not observed in ATO-insensitive cells. We reported that ATO treatment induced mitochondrial injury and mtDNA release into the cytoplasm in ATO-sensitive HCC tumors. This subsequently activated the cGAS-STING-IFN axis, facilitating CD8+ T cell infiltration and activation. However, we found that the IFN pathway also induced tumoral PD-L1 expression, potentially antagonizing ATO-mediated immune attack. Additional anti-PD1 therapy promoted the anti-tumor response of ATO in ATO-sensitive HCC tumors. In summary, our data indicate that heterogeneous ATO responses exist in HCC tumors, and ATO treatment significantly induces immunogenic cell death (ICD) and activates the tumor-derived mtDNA-STING-IFN axis. These findings may offer a new perspective on the clinical treatment of HCC and warrant further study.

Association between Statins Administration and Influenza Susceptibility: A Systematic Review and Meta-Analysis of Longitudinal Studies

Previous studies reported that the association between statins use and influenza infection was contradictory. A systematic review and meta-analysis of longitudinal studies were performed to determine the association between statins use and influenza susceptibility. The literature search was conducted in PubMed, Embase, and Web of Science, from each database's inception to 21 May 2023. The fixed effect model and random effects model were used for data synthesis. In our study, a total of 1,472,239 statins users and 1,486,881 statins non-users from five articles were included. The pooled risk ratio (RR) of all included participants was 1.05 (95% CI: 1.03-1.07), and there were still significant differences after adjusting for vaccination status. Of note, RR values in statins users were 1.06 (95% CI: 1.03-1.08) in people aged ≥60 years old and 1.05 (95% CI: 1.03-1.07) in participant groups with a higher proportion of females. Administration of statins might be associated with an increased risk of influenza infection, especially among females and elderly people. For those people using statins, we should pay more attention to surveillance of their health conditions and take measures to prevent influenza infection.

Examining Chronic Inflammation, Immune Metabolism, and T Cell Dysfunction in HIV Infection

Chronic Human Immunodeficiency Virus (HIV) infection remains a significant challenge to global public health. Despite advances in antiretroviral therapy (ART), which has transformed HIV infection from a fatal disease into a manageable chronic condition, a definitive cure remains elusive. One of the key features of HIV infection is chronic immune activation and inflammation, which are strongly associated with, and predictive of, HIV disease progression, even in patients successfully treated with suppressive ART. Chronic inflammation is characterized by persistent inflammation, immune cell metabolic dysregulation, and cellular exhaustion and dysfunction. This review aims to summarize current knowledge of the interplay between chronic inflammation, immune metabolism, and T cell dysfunction in HIV infection, and also discusses the use of humanized mice models to study HIV immune pathogenesis and develop novel therapeutic strategies.