Search Results (183)

Human cytomegalovirus (HCMV) establishes lifelong latency following primary infection, residing within myeloid progenitor cells and monocytes. To achieve this, the virus employs multiple immune evasion strategies. It suppresses innate immune signaling by inhibiting Toll-like receptor and cGAS-STING pathways. In addition, the virus suppresses major histocompatibility complex (MHC)-dependent antigen presentation to evade T cell recognition. As the downregulation of MHC molecules may trigger NK cell activation, the virus compensates for this by expressing proteins such as UL40 and IL-10, which engage inhibitory NK cell receptors and block activating signals, thereby suppressing NK cell immune surveillance. Viral proteins like UL36 and UL37 block host cell apoptosis and necroptosis, allowing HCMV to persist undetected and avoid clearance. In settings of profound immunosuppression, such as after allogeneic hematopoietic stem cell transplantation (allo-HSCT) or solid organ transplantation, slow immune reconstitution creates a window for viral reactivation. Likewise, immunosenescence and chronic low-grade inflammation during aging increases the risk of reactivation. Once reactivated, HCMV triggers programmed cell death, releasing viral PAMPs (pathogen-associated molecular patterns) and host-derived DAMPs (damage-associated molecular patterns). This release fuels a potent inflammatory response, promoting further viral reactivation and exacerbating tissue damage, creating a vicious cycle. This cycle of inflammation and reactivation contributes to both transplant-related complications and the decline of antiviral immunity in the elderly. Therefore, understanding the immune regulatory mechanisms that govern the switch from latency to reactivation is critical, especially within the unique immune landscapes of transplantation and aging. Elucidating these pathways is essential for developing strategies to prevent and treat HCMV-related disease in these high-risk populations. Full article

The success of mRNA-based SARS-CoV-2 vaccines has been confirmed in both preclinical and clinical settings. However, the development of safe and efficient mRNA vaccine delivery platforms remains challenging. In this report, PBAE-G-B-SS-modified CaO₂ nanofibers and Au@OVA@Cu@Dendrobium huoshanense polysaccharides were employed to establish novel self-assembling polymeric micelles (CaO₂@Au@OVA@Cu@DHPs) capable of serving as both an adjuvant and a delivery system for mRNA vaccines. In vitro, CaO₂@Au@OVA@Cu@DHPs nanoparticles (NPs) were conducive to effective macrophage antigen uptake and efficient antigen processing. In vivo, P-CaO₂@Au@OVA@Cu@DHPs NP administration was associated with a reduction in the ovalbumin (OVA) release rate that was conducive to the sustained induction of long-term immunity and to the production of higher levels of different IgG subtypes, suggesting that these effects were attributable to enhanced antigen uptake by antigen-presenting cells. Overall, these present data highlight the promise of these P-CaO₂@Au@OVA@Cu@DHPs NPs as an effective and safe platform amenable to vaccine delivery through their ability to provide robust adjuvant activity and sustained antigen release capable of eliciting long-term immunological memory while potentiating humoral and cellular immune responses. Full article

Overcoming immune resistance remains the critical barrier to durable immunotherapy responses. Tumors with non-inflamed, “cold” microenvironments exclude cytotoxic lymphocytes and evade checkpoint blockade. Innate nucleic acid-sensing pathways—including TLRs, RIG-I-like RNA sensors, and the cGAS–STING DNA-sensing axis—can recondition this hostile landscape by licensing dendritic cells, restoring antigen presentation, and recruiting effector T and NK cells. In this review, we synthesize mechanistic insights into how these receptors function across tumor and immune compartments and evaluate recent translational advances spanning small-molecule and nucleic acid agonists, engineered delivery systems, and clinical trials. We highlight challenges that have limited clinical impact, including pathway silencing, systemic toxicity, and lack of predictive biomarkers, while emphasizing emerging solutions such as tumor-intrinsic targeting, CAR-T/NK engineering, and biomarker-guided patient selection. By integrating innate activation into rational combination regimens, innate immune reprogramming offers a blueprint to convert resistant disease into one susceptible to durable immune control. Full article

Cardiovascular diseases hinge on a vicious, self-amplifying cycle in which mitochondrial deoxyribonucleic acid (mtDNA) dysfunction undermines cardiac bioenergetics and unleashes sterile inflammation. The heart’s reliance on oxidative phosphorylation (OXPHOS) makes it exquisitely sensitive to mtDNA insults—mutations, oxidative lesions, copy-number shifts, or aberrant methylation—that impair ATP production, elevate reactive oxygen species (ROS), and further damage the mitochondrial genome. Damaged mtDNA fragments then escape into the cytosol, where they aberrantly engage cGAS–STING, TLR9, and NLRP3 pathways, driving cytokine storms, pyroptosis, and tissue injury. We propose that this cycle represents an almost unifying pathogenic mechanism in a spectrum of mtDNA-driven cardiovascular disorders. In this review, we aim to synthesize the pathophysiological roles of mtDNA in this cycle and its implications for cardiovascular diseases. Furthermore, we seek to evaluate preclinical and clinical strategies aimed at interrupting this cycle—bolstering mtDNA repair and copy-number maintenance, reversing pathogenic methylation, and blocking mtDNA-triggered innate immune activation—and discuss critical gaps that must be bridged to translate these approaches into precision mitochondrial genome medicine for cardiovascular disease. Full article

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is recognized by pattern recognition receptors (PRRs), which play a vital role in triggering innate immune responses such as the production of type I and III interferons (IFNs). While modest PRR activation helps to defend against SARS-CoV-2, excessive or sustained activation can cause harmful inflammation and contribute to severe Coronavirus Disease 2019 (COVID-19). Altered expression of Toll-like receptors (TLRs), which are among the most important members of the PRR family members, particularly TLRs 2, 3, 4, 7, 8 and 9, has been strongly linked to COVID-19 severity. Furthermore, retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5), collectively known as RLRs (RIG-I-like receptors), act as sensors that detect SARS-CoV-2 RNA. The expression of these receptors, as well as that of different DNA sensors, varies in patients infected with SARS-CoV-2. Changes in PRR expression, particularly that of TLRs, cyclic GMP-AMP synthase (cGAS), and the stimulator of interferon genes (STING), have also been shown to play a role in the development and persistence of long COVID (LC). However, SARS-CoV-2 has evolved strategies to evade PRR recognition and subsequent signaling pathway activation, contributing to the IFN response dysregulation observed in SARS-CoV-2-infected patients. Nevertheless, PRR agonists and antagonists remain promising therapeutic targets for SARS-CoV-2 infection. This review aims to describe the PRRs involved in recognizing SARS-CoV-2, explore their expression during SARS-CoV-2 infection, and examine their role in determining the severity of both COVID-19 and long-term manifestations of the disease. It also describes the strategies developed by SARS-CoV-2 to evade PRR recognition and activation. Moreover, given the considerable interest in modulating PRR activity as a novel immunotherapy approach, this review will provide a description of PRR agonists and antagonists that have been investigated as antiviral strategies against SARS-CoV-2. This review aims to explore the complex interplay between PRRs and SARS-CoV-2 in depth, considering its implications for prognostic biomarkers, targeted therapeutic strategies and the mechanistic understanding of long LC. Additionally, it outlines future perspectives that could help to address knowledge gaps in PRR-mediated responses during SARS-CoV-2 infection. Full article

Type 2 diabetes mellitus (T2DM), characterized by insulin resistance and chronic hyperglycemia, markedly increases the incidence and mortality of cardiovascular disease (CVD). Emerging preclinical evidence identifies the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS–STING) pathway as a critical mediator of diabetic cardiovascular inflammation. Metabolic stressors in T2DM—hyperglycemia, lipotoxicity, and mitochondrial dysfunction—induce leakage of mitochondrial and microbial double-stranded DNA into the cytosol, where it engages cGAS and activates STING. Subsequent TBK1/IRF3 and NF-κB signaling drives low-grade inflammation across cardiomyocytes, endothelial cells, macrophages, and fibroblasts. Genetic deletion of cGAS or STING in high-fat-diet-fed diabetic mice reduces NLRP3 inflammasome-mediated pyroptosis, limits atherosclerotic lesion formation, and preserves cardiac contractile performance. Pharmacological inhibitors, including RU.521 (cGAS antagonist), C-176/H-151 (STING palmitoylation blockers), and the TBK1 inhibitor amlexanox, effectively lower pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and improve left ventricular ejection fraction in diabetic cardiomyopathy and ischemia–reperfusion injury models. Novel PROTAC degraders targeting cGAS/STING and natural products such as Astragaloside IV and Tanshinone IIA further support the pathway’s druggability. Collectively, these findings position the cGAS–STING axis as a central molecular nexus linking metabolic derangement to cardiovascular pathology in T2DM and underscore its inhibition or targeted degradation as a promising dual cardiometabolic therapeutic strategy. Full article

Objectives: Immunotherapy combining agonists of the cyclic GMP-AMP synthase–stimulator of interferon genes (cGAS-STING) pathway with PD-1/PD-L1 blockade shows promising preclinical results, although in clinical practice, it faces pharmacokinetic barriers, systemic toxicity, and an immunosuppressive tumor microenvironment (TME). Recent advances in and expansion of the cGAS-STING pathway as a therapeutic target have further highlighted its central role in innate and adaptive immune activation. The aim of this paper is to review combination strategies of STING and PD-1/PD-L1 checkpoint blockade therapies, triple-therapy strategies using a third component such as chemotherapy, radiotherapy, photodynamic therapy (PDT), and others, and the use of nanoparticles as carriers for these drugs. Methods: Reports in the literature on the mechanisms of STING + PD-1/PD-L1 synergy, as well as with the use of a third component and delivery systems, were analyzed. Current challenges and limitations, as well as prospects for the development of these therapies, are noted. Results: Activation of the cGAS-STING synergizes with blocking the PD-1/PD-L1 axis. The addition of a third component further enhances the anti-tumor effect through a stronger induction of immunogenic cell death (ICD), increased production of interferons and pro-inflammatory cytokines, repolarization of macrophages, and enhanced infiltration of T lymphocytes. Conclusions: Therapy with STING agonists and PD-1/PD-L1 checkpoint inhibitors, supported by nanotechnology vehicles and using a third therapeutic component, overcomes key pharmacological and immunological limitations. This multimodal immunotherapeutic strategy holds high translational promise, offering more effective and safer solutions in cancer immunotherapy. Full article

The cGAS-STING pathway initiates the core cascade of innate immune defense by recognizing pathogen-associated and self-derived abnormal nucleic acids, and key molecules (such as cGAS, STING, downstream IFN-β, IL-6, etc.) may serve as biomarkers in various diseases. The diverse mechanisms by which distinct nucleic acids activate this pathway provide novel insights for therapeutic strategies targeting infectious diseases, cancer, and autoimmune disorders. To prevent aberrant cGAS-STING pathway activation, cells employ multiple regulatory mechanisms, including restricting self-DNA recognition and terminating downstream signaling. Strategies to mitigate pathological activation involve reducing nucleic acid accumulation through nuclease degradation (e.g., of mitochondrial DNA or neutrophil extracellular traps, NETs) or directly inhibiting cGAS or STING. This review elucidates the molecular mechanism of nucleic acid-mediated regulation of cGAS-STING and its role in disease regulation. Full article

Breast cancer (BC) remains a leading cause of cancer-related mortality worldwide, with limited treatment options for triple-negative breast cancer (TNBC). The RNA-binding protein non-POU domain-containing octamer-binding protein (NONO) has emerged as a critical regulator of tumorigenesis, but its role in immune signaling remains unexplored. We analyzed the effect of NONO protein by modulating its expression using short hairpin RNA (shRNA) and a chemical inhibitor (R)-SKBG-1. We demonstrate that NONO depletion in MDA-MB-231 TNBC cells leads to cytoplasmic DNA accumulation, micronuclei formation, and activation of the cyclic GMP-AMP synthase—stimulator of interferon genes (cGAS/STING) pathway, resulting in enhanced modulation of the immune response. NONO-deficient cells showed increased cGAS and STING activation, Tank-binding kinase 1 (TBK1) phosphorylation, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) nuclear localization, and transcription of pro-inflammatory genes such as CC Motif Chemokine Ligand 5 (CCL5). These effects were recapitulated by pharmacological inhibition using (R)-SKBG-1, confirming NONO’s immunosuppressive function. Our findings establish NONO as a key modulator of immune activation in TNBC and suggest that its inhibition may enhance anti-tumor immunity. This work paves the way for potential combination strategies involving NONO inhibitors and immune checkpoint blockade, particularly in tumors with homologous recombination deficiencies or limited immune infiltration. Full article

Diabetic cardiomyopathy (DCM) is a serious complication of type 2 diabetes mellitus (T2DM), characterized by cardiac dysfunction, inflammation, and fibrosis. In this study, a T2DM mouse model was established by administering a high-fat diet (60% fat) in combination with streptozotocin injection in male C57BL/6J mice. The mice subsequently underwent an eight-week exercise intervention consisting of swimming training, resistance training, or high-intensity interval training (HIIT). The results showed that all three forms of exercise improved cardiac function and attenuated myocardial hypertrophy in DCM mice. Exercise training further downregulated the expression of pro-inflammatory cytokines, including interleukin-6, tumor necrosis factor-α, nuclear factor κB, and monocyte chemoattractant protein-1, and mitigated myocardial fibrosis by suppressing fibronectin, α-SMA, collagen type I alpha 1 chain, collagen type III alpha 1 chain, and the TGF-β1/Smad signaling pathway. Moreover, exercise inhibited the expression of PANoptosis-related genes and proteins in cardiomyocytes of DCM mice. Notably, HIIT produced the most pronounced improvements across these pathological markers. In addition, all three exercise modalities effectively suppressed the aberrant activation of the cGAS–STING signaling pathway in the myocardium. In conclusion, exercise training exerts beneficial effects against DCM by improving cardiac function and reducing inflammation, PANoptosis, and fibrosis, and HIIT emerged as the most effective strategy. Full article

Background. The STING protein is activated by the second messenger cGAMP to promote the innate immune response against infections. Beyond this role, a chronically overactive STING signaling has been described in several disorders. Patients with severe COVID-19 exhibit a hyper-inflammatory response (the cytokine storm) that is in part mediated by the cGAS-STING pathway. Several STING inhibitors may protect from severe COVID-19 by down-regulating several inflammatory cytokines. This pathway has been implicated in the establishment of an optimal antiviral vaccine response. STING agonists as adjuvants improved the IgG titers against the SARS-CoV-2 Spike protein vaccines. Methods. We investigated the association between two common functional STING1/TMEM173 polymorphisms (rs78233829 C>G/p.Gly230Ala and rs1131769C>T/p.His232Arg) and severe COVID-19 requiring hospitalization. A total of 801 non-vaccinated and 105 fully vaccinated (mRNA vaccine) patients, as well as 300 population controls, were genotyped. Frequencies between the groups were statistically compared. Results. There were no differences for the STING1 variant frequencies between non-vaccinated patients and controls. Vaccinated patients showed a significantly higher frequency of rs78233829 C (230Gly) compared to non-vaccinated patients (CC vs. CG + GG; p = 0.003; OR = 2.13; 1.29–3.50). The two STING1 variants were in strong linkage disequilibrium, with the rs78233829 C haplotypes being significantly more common in the vaccinated (p = 0.02; OR = 1.66; 95%CI = 1.01–2.55). We also studied the LTZFL1 rs67959919 G/A polymorphism that was significantly associated with severe COVID-19 (p < 0.001; OR = 1.83; 95%CI = 1.28–2.63). However, there were no differences between the non-vaccinated and vaccinated patients for this polymorphism. Conclusions. We report a significant association between common functional STING1 polymorphisms and the risk of developing severe COVID-19 among fully vaccinated patients. Full article

Immunotherapy targeting the immune functions of the tumor microenvironment (TME) is beneficial for colorectal cancer; however, the response rate is poor. Ciprofloxacin is a fluoroquinolone-class antibiotic that is used to treat bacterial infections. The purpose of this study is to assess the mechanism of ciprofloxacin that enhances anti-PD1 in colorectal cancer. We found that ciprofloxacin induced cytosolic DNA, including single-stranded and double-stranded DNA, formation in mouse CT26 colorectal adenocarcinoma cells. Molecules in DNA-sensing signaling such as cGAS, STING, and IFNβ mRNA and protein expression were elicited after ciprofloxacin treatment in CT26 cells. STING siRNA abrogated the cGAS-STING pathway activation by ciprofloxacin. In vivo, ciprofloxacin exhibited a synergistic effect with anti-PD1 to suppress tumor growth in a CT26 syngeneic animal model without biological toxicity. The examination of TME revealed that ciprofloxacin, alone and in combination therapy, induced M1 and red pulp macrophage production in the spleen. In tumors, M1 and M2 macrophage levels were increased by ciprofloxacin, and CD8⁺ T cell granzyme B expression was increased after combination therapy. STING showed the highest expression in tumor specimens after combination treatment. Ciprofloxacin may enhance the anti-PD1 efficacy and modulate the TME through the cGAS-STING pathway. Full article

Diabetic nephropathy (DN) represents a severe microvascular complication of diabetes mellitus. As a Traditional Chinese Medicine (TCM) with extensive clinical applications, Ligustri Lucidi Fructus (LLF) exhibits significant anti-DN activity. However, the underlying pharmacological mechanisms, crucial components, and targets for LLF in DN treatment remain unclear. By integrating network pharmacology, molecular docking, and molecular dynamics simulations, the bioactive compounds, potential therapeutic targets, and underlying mechanisms of LLF in the treatment of DN were elucidated, followed by biological validation in a palmitic acid (PA)-induced MPC5 podocyte injury model. Among the 383 DN-related LLF targets identified, TNF emerged as a pivotal one, demonstrating potential binding interaction with the active components salidroside (Sal), apigenin (Api), and tormentic acid (TA). Moreover, Gene Expression Omnibus (GEO) database and KEGG enrichment analysis collectively highlighted the cytosolic DNA-sensing pathway. Notably, the cGAS-STING pathway is central to this pathway. Experimental studies further demonstrated that LLF-containing serum exerted a protective effect on MPC5 podocytes through cGAS-STING pathway suppression. Overall, these findings elucidate the pleiotropic mechanisms underlying LLF’s protective effects against DN, integrating compound–target–pathway interactions and thus offering a rationale for further investigation. Full article

Objectives: This study aims to elucidate the potential molecular mechanism of Sinomenine (SIN) in treating renal injury in Diabetic Nephropathy (DN) through network pharmacology, molecular docking, and in vivo validation. Materials and Methods: db/db mice were used as a DN model to evaluate the therapeutic effects of SIN on body weight, blood glucose levels, renal function, and histopathology. Network pharmacology and molecular docking were integrated to predict the potential molecular mechanisms of SIN in DN treatment. Subsequently, in vivo validation was performed on db/db mice using ELISA, Western blotting, RT-qPCR, immunofluorescence, and immunohistochemistry. Results: Firstly, we found that SIN (62.4 mg/kg) improved general conditions and renal function in db/db mice, alleviating renal pathological damage. Network pharmacology analysis identified IL-1β, IL-6, and TNF-α as key targets of SIN in DN. SIN reduced IL-1β, IL-6, and TNF-α levels by inhibiting the cGAS/STING signaling pathway and its downstream p-TBK1, p-IRF3, and NF-κB expression. Conclusions: SIN alleviates inflammatory injury in DN, potentially through the cGAS/STING pathway. Full article

The unique secondary messenger 2′3′-cGAMP, produced by cGAS in response to cytosolic dsDNA, plays a critical role in activating innate immunity by binding to and activating STING via cell-intrinsic, autocrine, or paracrine mechanisms. Recently, we identified Rab18 as a novel, STING-independent binder of 2′3′-cGAMP. Binding of 2′3′-cGAMP to Rab18 promotes Rab18 activation and induces cell migration. However, the downstream mechanisms by which 2′3′-cGAMP-induced Rab18 activation regulates cell migration remain largely unclear. Herein, using phospho-profiling analysis, we identify MAPK signaling as a key downstream effector of the 2′3′-cGAMP/Rab18 axis that promotes the expression of FosB2 and drives cell migration. Furthermore, we identify MMP3 as a major transcriptional target of FosB2, through which the 2′3′-cGAMP/Rab18/MAPK/FosB2 signaling pathway positively regulates cell migration. Together, our findings provide new mechanistic insights into how 2′3′-cGAMP signaling controls cell migration and suggest the potential of MAPK inhibitors to block 2′3′-cGAMP-induced migratory responses. Full article