Danger Signals Research Articles

Lymphatic platelet thrombosis limits bone repair by precluding lymphatic transporting DAMPs

In the musculoskeletal system, lymphatic vessels (LVs), which are interdigitated with blood vessels, travel and form an extensive transport network. Blood vessels in bone regulate osteogenesis and hematopoiesis, however, whether LVs in bone affect fracture healing is unclear. Here, we investigate the lymphatic draining function at the tibial fracture sites using near-infrared indocyanine green lymphatic imaging (NIR-ICG) and discover that lymphatic drainage insufficiency (LDI) starts on day one and persists for up to two weeks following the fracture in male mice. Sufficient lymphatic drainage facilitates fracture healing in male mice. Furthermore, we identify that lymphatic platelet thrombosis (LPT) blocks the draining lymphoid sinus and LVs, causes LDI, and inhibits fracture healing in male mice, which can be rescued by a blood thinner. Moreover, unblocked lymphatic drainage decreases neutrophils and increases M2-type macrophages of the hematoma niche to support osteoblast (OB) survival and bone marrow-derived mesenchymal stem cell (BMSC) proliferation via transporting damage-associated molecular patterns (DAMPs) in male rats. Lymphatic platelet thrombolysis also benefits senile fracture healing in female mice. These findings demonstrate that LPT limits bone regeneration by impeding lymphatic transporting DAMPs. Together, these findings represent a way forward in the treatment of bone repair.

The actin cytoskeleton regulates danger-associated molecular pattern signaling and PEP1 RECEPTOR1 internalization.

In plants, cytoskeletal proteins assemble into dynamic polymers that play numerous roles in diverse fundamental cellular processes, including endocytosis, vesicle trafficking, and the spatial distribution of organelles and protein complexes. Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns (DAMPs) that are perceived by the receptor-like kinases PEP RECEPTOR 1 (PEPR1) and PEPR2 to enhance innate immunity and inhibit root growth in Arabidopsis (Arabidopsis thaliana). To date, however, there is little evidence that the actin cytoskeleton of the host cell participates in DAMP-induced innate immunity. Here, we demonstrated that the actin cytoskeleton alters the Pep1-triggered immune response. In addition, dual-color total internal reflection fluorescence-structured illumination microscopy (TIRF-SIM) showed that PEPR1 diffusion on the plasma membrane is closely related to the actin cytoskeleton. We performed single-particle tracking to quantify individual protein particles and found that the actin cytoskeleton notably regulates PEPR1 mobility and cluster size. More importantly, we demonstrated that actin filament reconfiguration is sufficient to inhibit Pep1-induced internalization, which alters the immune response. Taken together, these findings suggest that the actin cytoskeleton functions as an integration node for Pep1 signaling and PEPR1 endocytosis.

Reactive Metabolites Cause Idiosyncratic Drug-Induced Liver Injury via Inflammasome Activation in Antigen-Presenting Cells.

Although the pathophysiology of idiosyncratic drug-induced liver injury (IDILI) is unclear, it is presumed to be immune-mediated, involving complex interactions between drug metabolism and activation of the immune system. The following four reactive metabolite production patterns are considered: (1) parent compounds into reactive metabolites within neutrophils or antigen-presenting cells (APCs), (2) reactive metabolites produced by cytochrome P450 (CYP), (3) nonreactive metabolites produced by CYP into reactive metabolites within APCs, and (4) reactive metabolites produced by non-CYPs. Reactive metabolites indirectly activate inflammasomes in APCs, leading to IDILIs. These metabolites can cause cell damage, resulting in the release of damage-associated molecular patterns (DAMPs), which subsequently activate APCs. Given the diversity of DAMPs, comprehensive analyses are warranted to identify additional candidates. If validates, these DAMPs could be used as early biomarkers and predictive markers of IDILIs onset.

Extracellular peroxiredoxin 6 released from alveolar epithelial cells as a DAMP drives macrophage activation and inflammatory exacerbation in acute lung injury.

Acute respiratory distress syndrome (ARDS) is featured with acute lung inflammatory injury. Our prospective study found that higher levels of peroxiredoxin 6(PRDX6) were detected in bronchoalveolar lavage (BAL) fluid from ARDS patients. Elevated PRDX6 was also correlated with monocytic activation and poor prognosis in ARDS patients. To investigate the origin of extracellular PRDX6, we conducted in vitro and in vivo experiments, demonstrating that PRDX6 can be actively released from alveolar epithelial cells under stress conditions. Our study demonstrated that it could be released from injured lung epithelial cells into the bronchoalveolar interstitial space in mice with acute lung injury and in vitro experiments. Moreover, exogenous PRDX6 was shown to activate the TLR4/NF-κB signalling pathway and induce M1 polarization of macrophages. Notably, the inflammatory effects of PRDX6 were mitigated by specific inhibition of the TLR4 (Toll-like receptor 4)-MD2 (Myeloid differentiation factor 2) complex. Using molecular docking simulations and in vitro binding assays, we confirmed a direct interaction between PRDX6 and MD2, further supporting its role as a damage-associated molecular patterns (DAMP) in ARDS. Our findings suggest that extracellular PRDX6 in bronchoalveolar lavage fluid could be a new DAMP factor in ALI, providing new insights into the pathogenesis of secondary hit in ALI/ARDS and highlighting PRDX6 as a potential therapeutic target for mitigating lung inflammation.

Discovery of Innate Immune Response mRNAs That Are Impacted by Structure-Specific Oral Baker’s Yeast Beta Glucan Consumption

The study of nutritional compounds with the potential to train the innate immune response has implications for human health. The objective of the current study was to discover by what means 6 weeks of oral baker’s yeast beta glucan (BYBG) supplementation altered the mRNA expression of genes that reflect innate immune training in the absence of a physical stressor. Nineteen adults were randomly assigned to either a Wellmune® BYBG or Placebo for 6 weeks. BYBG uniquely altered the expression of 40 mRNAs associated with Dectin-1 and trained innate immunity, the innate immune response, the pathogen-associated (PAMP) and damage-associated molecular pattern (DAMP), and the inflammatory response. The observed changes were classified as immune training rather than immune priming due to the progressive increase in the expression of myeloid immune-associated mRNA. Combined with the findings of previous research, the findings of the present study support the claim that oral BYBG supplementation may be associated with trained innate immunity during resting homeostasis. Further, the key findings associated with BYBG may reflect improved responsiveness to future infection (exogenous) and/or sterile-inflammatory (endogenous) challenge.

An Albumin-Photosensitizer Supramolecular Assembly with Type I ROS-Induced Multifaceted Tumor Cell Deaths for Photodynamic Immunotherapy.

Photodynamic therapy holds great potentials in cancer treatment, yet its effectiveness in hypoxic solid tumor is limited by the oxygen-dependence and insufficient oxidative potential of conventional type II reactive oxygen species (ROS). Herein, the study reports a supramolecular photosensitizer, BSA@TPE-BT-SCT NPs, through encapsulating aggregation-enhanced emission photosensitizer by bovine serum albumin (BSA) to significantly enhance ROS, particularly less oxygen-dependent type I ROS for photodynamic immunotherapy. The abundant type I ROS generated by BSA@TPE-BT-SCT NPs induce multiple forms of programmed cell death, including apoptosis, pyroptosis, and ferroptosis. These multifaceted cell deaths synergistically facilitate the release of damage-associated molecular patterns and antitumor cytokines, thereby provoking robust antitumor immunity. Both in vitro and in vivo experiments confirmed that BSA@TPE-BT-SCT NPs elicited the immunogenic cell death, enhance dendritic cell maturation, activate T cell, and reduce myeloid-derived suppressor cells, leading to the inhibition of both primary and distant tumors. Additionally, BSA@TPE-BT-SCP NPs also exhibited excellent antitumor performance in a humanized mice model, evidenced by a reduction in senescent T cells among these activated T cells. The findings advance the development of robust type I photosensitizers and unveil the important role of type I ROS in enhancing multifaceted tumor cell deaths and antitumor immunogenicity.

Mechanisms of mitochondrial damage-associated molecular patterns associated with inflammatory response in cardiovascular diseases.

Cardiovascular diseases (CVDs) continue to be a substantial global healthcare burden despite considerable progress in therapies. The inflammatory response during the progression of CVD has attracted considerable attention. Mitochondria serve as the principal energy source for the heart. In cardiovascular illnesses, mitochondrial homeostasis is disrupted, accompanied by structural and functional impairments. During mitochondrial stress or injury, mitochondrial damage-associated molecular patterns (mtDAMPs), such as mitochondrial DNA, cardiolipin, N-formyl peptide, and adenosine triphosphate, are released to activate pattern recognition receptors and trigger immunological responses. Inflammatory responses mediated by mtDAMPs substantially contribute to the pathophysiology of cardiovascular illnesses. In this review, we discuss the molecular mechanisms by which different mtDAMPs control the inflammatory response, address the pathological consequences of mtDAMPs in inducing or exacerbating the inflammatory response in CVDs, and summarize potential therapeutic targets in relevant experimental studies. Preventing or reducing mtDAMP release may play a role in CVD progression by alleviating the inflammatory response.

The role of serum S100B and serum thyroid stimulating hormone levels in vitiligo.

Vitiligo is a depigmenting disorder characterized by melanocyte loss, which results in pigment dilution of the skin. Vitiligo is commonly associated with thyroid disorders and thyroid stimulating hormone (TSH) is a sensitive marker to detect thyroid disorders. S100B is damage associated molecular pattern (DAMP) molecule released when there is melanocyte damage. In this study, we are estimating the serum TSH and S100B levels in vitiligo patients and controls and correlating them with disease activity. A cross-sectional study was conducted on 39 cases of vitiligo and controls. Demographic details were collected, the cases were examined and Vitiligo European Task Force (VETF) scoring was performed. Serum S100B was analyzed using an ELISA kit and serum TSH levels were estimated. Age of the participants ranged from 14 to 81 years with a mean and standard deviation of 44.08 ± 16.078 years. Female preponderance was noted. Vitiligo vulgaris was the most common presentation. Serum TSH (p = 0.32) and S100B (p = 0.22) levels between cases and controls were not statistically significant. Serum S100B level had a weak positive correlation with the spreading component of VETF score and it was statistically significant (p = 0.004). Mucosal vitiligo had higher levels of serum S100B levels compared to other types of vitiligo. In our study both serum TSH and S100B levels have demonstrated limited utility in distinguishing between vitiligo patients and controls. S100B showed a weak correlation with VETF scores indicating its potential (though limited) as a disease activity marker. Therefore, the potential of using this as a biomarker is debatable, and further multicentric studies with a larger sample size are required to establish the correlation.

Investigating the impact of mitochondrial DNA: Insights into blood transfusion reactions and mitigation strategies.

Although transfusion reactions occur in less than 2% of recipients, they are currently one of the most serious concerns in blood transfusion. Damage-associated molecular patterns (DAMPs) are released from injured, stressed or dead cells, leading to inflammation and immune system activation. One of the recognized DAMPs is mitochondrial DNA (mtDNA). It is found in various blood products, including fresh frozen plasma (FFP), red blood cell units (RBCUs) and platelet concentrates (PCs), and can induce adverse reactions in recipients by stimulating the innate immune system and inflammatory cellular pathways. The aim of this study was to investigate the factors influencing the release of mtDNA in various blood products and its subsequent impact on transfusion reactions. In this study, mtDNA, mitochondrial DNA, mtDNA DAMPs, extracellular mtDNA, blood products, blood components and transfusion reactions between 2009 and 2023 were searched in Google Scholar, PubMed and Scopus databases. This study has demonstrated the presence of mtDNA in the extracellular milieu of various blood products, including PCs, FFP and RBCUs. Understanding the determinants of mtDNA release and its implications for transfusion safety is critical. Strategies aimed at reducing mtDNA release, such as optimizing preparation techniques and donor selection criteria, hold promise for reducing transfusion-related complications. By addressing these factors, healthcare providers can enhance the safety and efficacy of blood transfusion practices, ultimately improving patient outcomes.

Pharmacological inhibition of key metabolic pathways attenuates Leishmania spp infection in macrophages.

Macrophages represent a fundamental component of the innate immune system that play a critical role in detecting and responding to pathogens as well as danger signals. Leishmania spp. infections lead to a notable alteration in macrophage metabolism, whereby infected cells display heightened energy metabolism that is linked to the integrity of host mitochondria. However, little is known about how different species of Leishmania manipulate host metabolism. Here, we demonstrate that despite differences in their mechanisms for evading host immune responses, L. amazonensis and L. braziliensis induce comparable disruptions in key metabolic pathways. We found that infected macrophages exhibited an overall elevation in energy metabolism regardless of the parasite strain, evidenced by the elevation in glycolysis and oxygen consumption rates, along with increased proton leak and decreased ATP production. We also analyzed the effects of both Leishmania spp. strain infection on mitochondria function, further revealing that infected cells display heightened mitochondrial mass and membrane potential. To investigate the metabolic pathways required for Leishmania amastigotes to persist in BMDMs, we pre-treated cells with small molecule drugs that target major metabolic pathways, revealing that perturbations in several metabolic processes affected parasite survival in a strain-independent manner. Treatments with inhibitors of the oxidative phosphorylation and glycolysis substantially reduced parasite loads. Collectively, our findings suggest that L.amazonensis and L.braziliensis exploit host cell metabolic pathways similarly to survive in macrophages.

Roles of the Receptor for Advanced Glycation End Products and Its Ligands in the Pathogenesis of Alzheimer's Disease.

The Receptor for Advanced Glycation End Products (RAGE), part of the immunoglobulin superfamily, plays a significant role in various essential functions under both normal and pathological conditions, especially in the progression of Alzheimer's disease (AD). RAGE engages with several damage-associated molecular patterns (DAMPs), including advanced glycation end products (AGEs), beta-amyloid peptide (Aβ), high mobility group box 1 (HMGB1), and S100 calcium-binding proteins. This interaction impairs the brain's ability to clear Aβ, resulting in increased Aβ accumulation, neuronal injury, and mitochondrial dysfunction. This further promotes inflammatory responses and oxidative stress, ultimately leading to a range of age-related diseases. Given RAGE's significant role in AD, inhibitors that target RAGE and its ligands hold promise as new strategies for treating AD, offering new possibilities for alleviating and treating this serious neurodegenerative disease. This article reviews the various pathogenic mechanisms of AD and summarizes the literature on the interaction between RAGE and its ligands in various AD-related pathological processes, with a particular focus on the evidence and mechanisms by which RAGE interactions with AGEs, HMGB1, Aβ, and S100 proteins induce cognitive impairment in AD. Furthermore, the article discusses the principles of action of RAGE inhibitors and inhibitors targeting RAGE-ligand interactions, along with relevant clinical trials.

The reducing end of cell wall oligosaccharides is critical for DAMP activity in Arabidopsis thaliana and can be exploited by oligosaccharide oxidases in the reduction of oxidized phenolics.

The enzymatic hydrolysis of cell wall polysaccharides results in the production of oligosaccharides with nature of damage-associated molecular patterns (DAMPs) that are perceived by plants as danger signals. The in vitro oxidation of oligogalacturonides and cellodextrins by plant FAD-dependent oligosaccharide-oxidases (OSOXs) suppresses their elicitor activity in vivo, suggesting a protective role of OSOXs against a prolonged activation of defense responses potentially deleterious for plant health. However, OSOXs are also produced by phytopathogens and saprotrophs, complicating the understanding of their role in plant-microbe interactions. Here, we demonstrate the oxidation catalyzed by specific fungal OSOXs also converts the elicitor-active cello-tetraose and xylo-tetraose into elicitor-inactive forms, indicating that the oxidation state of cell wall oligosaccharides is crucial for their DAMP function, irrespective of whether the OSOX originates from fungi or plants. In addition, we also found that certain OSOXs can transfer the electrons from the reducing end of these oligosaccharides to oxidized phenolics (bi-phenoquinones) instead of molecular O2, highlighting an unexpected sub-functionalization of these enzymes. The activity of OSOXs may be crucial for a thorough understanding of cell wall metabolism since these enzymes can redirect the reducing power from sugars to phenolic components of the plant cell wall, an insight with relevant implications for plant physiology and biotechnology.

Ultrasound-activated erythrocyte membrane-camouflaged Pt (II) layered double hydroxide enhances PD-1 inhibitor efficacy in triple-negative breast cancer through cGAS-STING pathway-mediated immunogenic cell death.

Rationale: Immunogenic cell death (ICD) offers a promising avenue for the treatment of triple-negative breast cancer (TNBC). However, optimizing immune responses remains a formidable challenge. This study presents the design of RBCm@Pt-CoNi layered double hydroxide (RmPLH), an innovative sonosensitizer for sonodynamic therapy (SDT), aimed at enhancing the efficacy of programmed cell death protein 1 (PD-1) inhibitors by inducing robust ICD responses. Methods: Pt-CoNi layered double hydroxide (LDH) nanocages were synthesized using a two-step method, followed by functionalization with red blood cell membranes to prepare RmPLH. The in vitro assessments included evaluations of cell toxicity, cellular uptake, and sonodynamic effects of RmPLH. Key mechanisms-such as oxidative stress, DNA damage, pyroptosis, cGAS/STING pathway activation, and inhibition of cellular migration and invasion-were explored under varying treatment conditions in 4T1 cells. Tumor-bearing mice were employed to evaluate tumor-targeting capabilities and the synergistic tumor-suppressive effects of RmPLH combined with PD-1 inhibitors. Comprehensive safety evaluations, including blood tests, biochemical analyses, and histopathological examinations, were also conducted. Results: The synthesized Pt-CoNi LDH exhibited a uniform rhombic dodecahedral nanocage morphology with an average particle size of approximately 231 nm. Encapsulation with red blood cell membranes conferred prolonged systemic circulation, enhanced tumor targeting, and reduced immune clearance for RmPLH. Upon ultrasound (US) stimulation, the LDH released substantial levels of reactive oxygen species (ROS) and platinum ions. The ROS effectively induced endoplasmic reticulum stress and ferroptosis, while platinum ions facilitated DNA crosslinking, triggering significant DNA damage. ROS-induced pyroptosis released inflammatory mediators and damage-associated molecular patterns (DAMPs), which activated the cGAS/STING pathway and reinforced ICD. Combining RmPLH with PD-1 inhibitors significantly enhanced therapeutic efficacy against TNBC. Furthermore, safety assessments confirmed the excellent biocompatibility and biosafety of RmPLH. Conclusion: The integration of RmPLH with PD-1 inhibitors substantially amplifies ICD, fostering robust antigen-specific T cell immunity and offering a promising therapeutic strategy for TNBC. This study represents a pioneering application of Pt (II)-based LDH nanocages in oncology, laying a foundation for future innovations in tumor immunotherapy.

Ultrasound-triggered drug-loaded nanobubbles for enhanced T cell recruitment in cancer chemoimmunotherapy.

Chemotherapy combined with immunotherapy is a highly promising approach for treating tumors. However, chemotherapeutic drugs often fail to accumulate effectively at the tumor site after systemic administration and they lack sufficient immunogenicity to activate adaptive immunity, making an effective T-cell immune response within the tumor microenvironmentdifficult to achieve. Here, this work developed drug-loaded nanobubbles (DTX-R837@NBs) that encapsulate the chemotherapy drug docetaxel and the immune adjuvant R837 via a thin-film hydration method. Ultrasound-targeted nanobubble destruction promoted drug accumulation within tumor tissues and damaged tumor cells through the cavitation effect, inducing immunogenic cell death and releasing damage-associated molecular patterns to augment dendritic cell maturation. Notably, DTX-R837@NBs exhibited excellent contrast-enhanced ultrasound imaging capabilities, enabling the seamless integration of diagnosis and treatment. In combination with immune checkpoint blockade targeting programmed cell death protein 1 (PD-1), the generated immunological responses attacked residual tumor cells and ameliorated the immunosuppressive tumor microenvironment, inhibiting distant tumor growth and metastasis. Moreover, this strategy exhibited robust immune memory effects, effectively protecting the host and preventing tumor recurrence upon rechallenge. Overall, ultrasound-mediated DTX-R837@NBs combined with anti-PD-1 immune checkpoint blockade therapy exhibits robust antitumor efficiency, represent a promising strategy for overcoming immunotherapy resistance in cold tumors, and warrant further investigation for clinical translation.

Curcumin pretreatment prevents butyrate-induced cell death and release of damage-associated molecular patterns on gingival epithelial Ca9-22 cells.

Exposure of gingival epithelial cells to butyrate, a short-chain fatty acid produced by dental plaque bacteria, cause cell death and subsequent damage-associated molecular pattern (DAMP) release. We investigated the effects of curcumin, a polyphenol extracted from turmeric, on butyrate-induced human gingival epithelial Ca9-22 cell death and DAMP release. Ca9-22 cells were pretreated with curcumin before butyrate exposure. Cell death was quantified using SYTOX green dye, and histone H3 acetylation was analyzed by western blot. Conditioned media were collected to detect DAMPs by western blot. We also assessed the effects of the histone acetyltransferase (HAT) inhibitor C646, instead of curcumin, on butyrate-induced cell death, DAMP release, and histone H3 acetylation, and examined the effects of curcumin pretreatment on cell death, DAMP release, and histone H3 acetylation induced by the histone deacetylase (HDAC) inhibitors, valproate and suberoylanilide hydroxamic acid (SAHA). Curcumin pretreatment attenuated butyrate-induced Ca9-22 cell death, histone H3 acetylation, and release of the DAMPs. The C646 also attenuated butyrate-induced cell death, DAMP release, and histone H3 acetylation. Curcumin also suppressed cell death, DAMP release, and histone H3 acetylation triggered by the HDAC inhibitors (valproate and SAHA). Curcumin pretreatment ameliorated butyrate-induced histone H3 acetylation, cell death, and DAMP release. As elevated histone acetylation by HDAC inhibitors correlates with increased cell death, while reduced acetylation by a HAT inhibitor is associated with their attenuation, protective effects of curcumin against butyrate-induced Ca9-22 cell death and subsequent DAMP release may occur via suppression of histone acetylation.

Bacteria use exogenous peptidoglycan as a danger signal to trigger biofilm formation

For any organism, survival is enhanced by the ability to sense and respond to threats in advance. For bacteria, danger sensing among kin cells has been observed, but the presence or impacts of general danger signals are poorly understood. Here we show that different bacterial species use exogenous peptidoglycan fragments, which are released by nearby kin or non-kin cell lysis, as a general danger signal. Using microscopy and gene expression profiling of Vibrio cholerae, we find that even brief signal exposure results in a regulatory response that causes three-dimensional biofilm formation, which protects cells from a broad range of stresses, including bacteriophage predation. A diverse set of species (Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecalis) also respond to exogenous peptidoglycan by forming biofilms. As peptidoglycan from different Gram-negative and Gram-positive species triggered three-dimensional biofilm formation, we propose that this danger signal and danger response are conserved among bacteria.

S100A8 and S100A9–Critical Mediators of Inflammation in Arthritis

Abstract: Damage-associated molecular Patterns (DAMP) released on the onset of tissue injury interact predominantly with pattern-recognizing receptors (PRRs) and multiple receptors to trigger and mediate inflammation and play a critical role in the progression of various diseases. Among the multiple DAMPs, S100A8 (MRP-8) and S100A9 (MRP-14) are low molecular weight calcium- binding proteins primarily expressed in innate immune cells such as myeloid cells: neutrophils, monocytes, keratinocytes, and early differentiation states of macrophages giving them the name Myeloid related proteins (MRP). S100A8 and S100A9 can exist both as homo- and heterocomplexes – shown to elicit different functions in cellular physiology, chemotaxis, phagocyte migration and modulation of various macrophage functions, apoptosis in cancer, and activation of NF-κB pathway. S100A8 and S100A9 have been shown to trigger innate immunity via TLR-4 signaling, thereby increasing the production of proinflammatory cytokines and other downstream effectors of the cascade. An influx in S100A8 and S100A9 proteins has been implicated in the most prevalent arthritic conditions, such as rheumatoid arthritis (RA) and osteoarthritis (OA). Hence, the primary objective of the review is to provide a comprehensive and systematic analysis imparting insights into the role of S100A8 and S100A9 proteins as mediators of inflammation in RA and OA.

A metal-phenolic nanotuner induces cancer pyroptosis for sono-immunotherapy.

Although ultrasound therapy is efficacious and safe in clinical oncology, its capacity to elicit an anti-tumor immune response is constrained by ultrasound-induced apoptosis. Pyroptosis, which releases immunogenic damage-associated molecular patterns (DAMPs), can significantly enhance immune activation. It necessitates robust Gasdermin E (GSDME) expression in cancer cells for caspase-3-mediated pyroptosis. An epigenetic strategy is introduced to induce cancer pyroptosis during sonotherapy using a nanocoordinator (HTA) constructed through metal-phenolic coordination involving Aza (a DNA methyltransferase inhibitor), TiO2 nanoparticles, and polyphenol-modified hyaluronic acid. While Aza restores GSDME expression, TiO2 generates reactive oxygen species (ROS) under ultrasound stimulation, activating caspase-3 and inducing pyroptosis via GSDME cleavage. In an orthotopic breast cancer model, HTA enhanced anti-tumor immunity and improved the efficacy of sonodynamic therapy (SDT). This approach presents a novel strategy for augmenting SDT through epigenetically induced pyroptosis.

Chitosan-derived drug free “artificial beacon” simulating immunogenetic cell death cascade effector to initiate immune response for cancer therapy

Immunogenetic cell death (ICD) is widely participated in tumor immune therapy. However, the stress responses triggered by individual ICD inducers are typically not strong enough to effectively kickstart an ICD effect and successful ICD necessitates a high level of ICD stimulus, which may be linked to dose-related toxicity. In this research, we developed a drug-free “artificial beacon” ATP/CSO@ECM that mimics the ICD cascade system to kickstart an immune response with cationic chitosan (CSO) as a bridge, which participated in integrating tumor antigens and functional damage-associated molecular patterns (DAMPs) into one effector by electrostatic interaction. This beacon is made up of ATP/CSO nanocomplexes covered by an engineered cell membrane (ECM), which is verified to enrich with high mobility group box 1 (HMGB1) and calreticulin (CRT). When exposed to the acidic tumor environment, the ATP/CSO@ECM underwent a morphological change by proton buffering capability of CSO. This resulted in the release of simulated DAMPs and the adjuvant CSO, all of which collaborated to activate dendritic cells and ultimately prolong the effectiveness of immunotherapy. This chitosan-derived “artificial beacon” ATP/CSO@ECM fully mobilizes the function of CSO and avoids the insufficient ICD effect by concentrating signaling molecules, providing a hopeful strategy for using the ICD process in targeted cancer therapy.

Platelet backpacking nanoparticles based on bacterial outer membrane vesicles enhanced photothermal-immune anti-tumor therapy.

Bacterial outer membrane vesicles (OMVs), produced by Gram-negative bacteria, retain the immunostimulatory capacity of parental bacteria. OMVs have been recognized as potent natural immune adjuvants and drug delivery vehicles. Photothermal therapy that triggers immunogenic cell death further stimulates the immune system by releasing damage-associated molecular patterns. This therapeutic effect can be synergized with OMVs to achieve enhanced anti-tumor outcomes. We also observed that tumors can recruit platelets. Leveraging the phenomenon, we have innovatively employed platelets as "couriers" to boost the tumor-targeting delivery efficiency of both OMVs and photothermal agents. In detail, based on OMVs, we meticulously engineered nanoparticles (IR780-SLN@O-P) with platelet-binding capacity. These "courier" platelets carry "cargo" IR780-SLN@O-P NPs to tumor sites via P-selectin, ensuring targeted delivery. Under laser irradiation, the photothermal agents generate significant photothermal effects, which combined with the immune-stimulating properties of OMVs, creating a robust anti-tumor immune response. For "cold" tumors such as triple-negative breast cancer (TNBC), our IR780-SLN@O-P NPs not only prolonged the survival of mice bearing 4T1 orthotopic tumors, but also significantly suppressed tumor growth. Moreover, they facilitated dendritic cell maturation and the infiltration of CD8+ T cells to ameliorate the immunosuppressive tumor environment. Our research aims to highlight the unique advantages of OMVs and explore the potential of the tumor-targeting strategy that synergizes photothermal therapy with immunotherapy. We hope that our findings can offer insights into TNBC clinical treatments.