Antigen-presenting Dendritic Cells Research Articles

Immunological nanomaterials to combat cancer metastasis.

Metastasis causes greater than 90% of cancer-associated deaths, presenting huge challenges for detection and efficient treatment of cancer due to its high heterogeneity and widespread dissemination to various organs. Therefore, it is imperative to combat cancer metastasis, which is the key to achieving complete cancer eradication. Immunotherapy as a systemic approach has shown promising potential to combat metastasis. However, current clinical immunotherapies are not effective for all patients or all types of cancer metastases owing to insufficient immune responses. In recent years, immunological nanomaterials with intrinsic immunogenicity or immunomodulatory agents with efficient loading have been shown to enhance immune responses to eliminate metastasis. In this review, we would like to summarize various types of immunological nanomaterials against metastasis. Moreover, this review will summarize a series of immunological nanomaterial-mediated immunotherapy strategies to combat metastasis, including immunogenic cell death, regulation of chemokines and cytokines, improving the immunosuppressive tumour microenvironment, activation of the STING pathway, enhancing cytotoxic natural killer cell activity, enhancing antigen presentation of dendritic cells, and enhancing chimeric antigen receptor T cell therapy. Furthermore, the synergistic anti-metastasis strategies based on the combinational use of immunotherapy and other therapeutic modalities will also be introduced. In addition, the nanomaterial-mediated imaging techniques (e.g., optical imaging, magnetic resonance imaging, computed tomography, photoacoustic imaging, surface-enhanced Raman scattering, radionuclide imaging, etc.) for detecting metastasis and monitoring anti-metastasis efficacy are also summarized. Finally, the current challenges and future prospects of immunological nanomaterial-based anti-metastasis are also elucidated with the intention to accelerate its clinical translation.

Optogenetic Engineering of STING Signaling to Remotely Control anti-Tumor Immunity

The cGAS-STING signaling pathway is regarded as a promising target for cancer therapeutics development. Here we present an ultra-light-sensitive optogenetic device, designated LiSmore for light-inducible SMOC-like repeats, that remotely control STING activation and downstream gene expression in antigen-presenting cells to mount innate immunity. We demonstrate that noninvasive light-triggered STING modulation effectively promotes dendritic cell (DC) maturation and antigen presentation, allowing T cells to be effectively sensitized to engage tumor antigens, thereby photo-boosting anti-tumor immune response. Importantly, combining LiSmore with immune checkpoint blocker (ICB) synergistically enhances antitumor effcacy in an immunosuppressive lung cancer model, which otherwise remains largely unresponsive to ICB treatment. Our findings establish that targeted optogenetic activation of STING signaling allows for the remote control of DC functions by boosting anti-tumor immunity at the tumor sites. Hence, LiSmore sets the stage for the development of wireless optogenetic immunomodulatory therapies in a light-switchable manner. Acknowledgment: This work was supported by the Welch Foundation (BE-1913-20220331 to Y.Z.), the Cancer Prevention and Research Institutes of Texas (RP210070 to Y.Z.), and the National Institutes of Health (R01GM144986 to Y.Z., R01HL134780 to R01 Y.H., R01HL146852 to Y.H., and R01CA240258 to Y.H.). Images were created by Biorender.com. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Autophagy‐Inducing MoO3‐x Nanowires Boost Photothermal‐Triggered Cancer Immunotherapy

Autophagy could play suppressing role in cancer therapy by facilitating release of tumor antigens from dying cells and inducing immunogenic cell death (ICD). Therefore, discovery and rational design of more effective inducers of cytotoxic autophagy is expected to develop new strategies for finding innovative drugs for precise and successful cancer treatment. Herein, we develop MoO3‐x nanowires (MoO3‐x NWs) with high oxygen vacancy and strong photothermal responsivity to ablate tumors through hyperthermia, thus promote the induction of cytotoxic autophagy and severe ICD. As expected, the combination of MoO3‐x NWs and photothermal therapy (PTT) effectively induces autophagy to promote the release of tumor antigens from the ablated cells, and induces the maturation and antigen presentation of dendritic cells (DCs), subsequently activates cytotoxic T lymphocytes (CTLs)‐mediated adaptive immunity. Furthermore, the combination treatment of MoO3‐x NWs with immune checkpoint blockade of PD‐1 could promote the tumor‐associated macrophages (TAMs) polarization into tumor‐killing M1 macrophages, inhibit infiltration of Treg cells at tumor sites, and alleviate immunosuppression in the tumor microenvironment, finally intensify the anti‐tumor activity in vivo. This study provides a strategy and preliminary elucidation of the mechanism of using MoO3‐x nanowires with high oxygen vacancy to induce autophagy and thus enhance photothermal immunotherapy.

Autophagy-Inducing MoO3-x Nanowires Boost Photothermal-Triggered Cancer Immunotherapy.

Autophagy could play suppressing role in cancer therapy by facilitating release of tumor antigens from dying cells and inducing immunogenic cell death (ICD). Therefore, discovery and rational design of more effective inducers of cytotoxic autophagy is expected to develop new strategies for finding innovative drugs for precise and successful cancer treatment. Herein, we develop MoO3-x nanowires (MoO3-x NWs) with high oxygen vacancy and strong photothermal responsivity to ablate tumors through hyperthermia, thus promote the induction of cytotoxic autophagy and severe ICD. As expected, the combination of MoO3-x NWs and photothermal therapy (PTT) effectively induces autophagy to promote the release of tumor antigens from the ablated cells, and induces the maturation and antigen presentation of dendritic cells (DCs), subsequently activates cytotoxic T lymphocytes (CTLs)-mediated adaptive immunity. Furthermore, the combination treatment of MoO3-x NWs with immune checkpoint blockade of PD-1 could promote the tumor-associated macrophages (TAMs) polarization into tumor-killing M1 macrophages, inhibit infiltration of Treg cells at tumor sites, and alleviate immunosuppression in the tumor microenvironment, finally intensify the anti-tumor activity in vivo. This study provides a strategy and preliminary elucidation of the mechanism of using MoO3-x nanowires with high oxygen vacancy to induce autophagy and thus enhance photothermal immunotherapy.

TFEB regulates dendritic cell antigen presentation to modulate immune balance in asthma

ObjectiveAsthma stands as one of the most prevalent chronic respiratory conditions in children, with its pathogenesis tied to the actived antigen presentation by dendritic cells (DCs) and the imbalance within T cell subgroups. This study seeks to investigate the role of the transcription factor EB (TFEB) in modulating the antigen presentation process of DCs and its impact on the differentiation of T cell subgroups.MethodsBone marrow dendritic cells (BMDCs) were activated using house dust mites (HDM) and underwent RNA sequencing (RNA-seq) to pinpoint differentially expressed genes. TFEB mRNA expression levels were assessed in the peripheral blood mononuclear cells (PBMCs) of both healthy children and those diagnosed with asthma. In an asthma mouse model induced by HDM, the TFEB expression in lung tissue DCs was evaluated. Further experiments involved LV-shTFEB BMDCs co-cultured with T cells to explore the influence of TFEB on DCs’ antigen presentation, T cell subset differentiation, and cytokine production.ResultsTranscriptomic sequencing identified TFEB as a significantly differentially expressed gene associated with immune system pathways and antigen presentation. Notably, TFEB expression showed a significant increase in the PBMCs of children diagnosed with asthma compared to healthy counterparts. Moreover, TFEB exhibited heightened expression in lung tissue DCs of HDM-induced asthmatic mice and HDM-stimulated BMDCs. Silencing TFEB resulted in the downregulation of MHC II, CD80, CD86, and CD40 on DCs. This action reinstated the equilibrium among Th1/Th2 and Th17/Treg cell subgroups, suppressed the expression of pro-inflammatory cytokines like IL-4, IL-5, IL-13, and IL-17, while augmenting the expression of the anti-inflammatory cytokine IL-10.ConclusionTFEB might have a vital role in asthma’s development by impacting the antigen presentation of DCs, regulating T cell subgroup differentiation, and influencing cytokine secretion. Its involvement could be pivotal in rebalancing the immune system in asthma. These research findings could potentially unveil novel therapeutic avenues for treating asthma.

Abstract P53: Inhibition of STING/Galectin-9 Axis Sensitize Anthracyclines Treatment And Induce Anti-tumor Immunity

Abstract Anthracyclines, are a class of conventional and routinely used firstline chemotherapy drugs to treat breast cancer. Immunogenic cell death (ICD) is characterized by the exposure of danger signals that promote dendritic cell maturation and antigen presentation and is often associated with the induction of cancer cell-intrinsic IFN-I signaling pathway. In addition, among multiple chemotherapeutic drugs such as doxorubicin (Dox) is well-known to promote tumor immunogenicity by interfering with DNA synthesis. Galectin-9 (Gal-9), as a member of β-galactoside-binding protein family, has been demonstrated to induce T cell death and promote immunosuppression in the tumor microenvironment. In addition, it has been shown that some interferon (IFN) and interleukin (IL) factors can induce Gal-9 expression. However, the mechanism cross-talk between anthracyclines and Gal-9 immunecheckpoint inhibitor remains unknown. Here we show that doxorubicin induces PD-L1 expression in human breast cancer cell lines and animal models. Mechanistically, doxorubicin promoted IFNβ expression, which in turn enhanced doxorubicin-induced Gal-9. Furthermore, we discovered that doxorubicin induces tumor Gal-9 via STING upregulation. The combination of doxorubicin and anti-Gal-9 therapy compared with each agent alone significantly increased the therapeutic efficacy in vivo. Clinically, a higher Gal-9 and p-STING level in the tumor region of after-treatment anthracyclines as compared to before treatment is indicated in breast cancer tumor tissue. Taken together, our study demonstrates crosstalk between anthracyclines-induced ICD and tumor-associated immunosuppression and provides a novel therapeutic strategy by combining anthracyclines and Gal-9 antibody in breast cancer. Citation Format: Xian Sun, Wei-Jan Wang, Jilu Lang, Riyao Yang, Wan-Jou Shen, Linlin Sun, Mien-Chie Hung. Inhibition of STING/Galectin-9 Axis Sensitize Anthracyclines Treatment And Induce Anti-tumor Immunity [abstract]. In: Proceedings of Frontiers in Cancer Science; 2023 Nov 6-8; Singapore. Philadelphia (PA): AACR; Cancer Res 2024;84(8_Suppl):Abstract nr P53.

Genome-wide screening identifies Trim33 as an essential regulator of dendritic cell differentiation.

The development of dendritic cells (DCs), including antigen-presenting conventional DCs (cDCs) and cytokine-producing plasmacytoid DCs (pDCs), is controlled by the growth factor Flt3 ligand (Flt3L) and its receptor Flt3. We genetically dissected Flt3L-driven DC differentiation using CRISPR-Cas9-based screening. Genome-wide screening identified multiple regulators of DC differentiation including subunits of TSC and GATOR1 complexes, which restricted progenitor growth but enabled DC differentiation by inhibiting mTOR signaling. An orthogonal screen identified the transcriptional repressor Trim33 (TIF-1γ) as a regulator of DC differentiation. Conditional targeting in vivo revealed an essential role of Trim33 in the development of all DCs, but not of monocytes or granulocytes. In particular, deletion of Trim33 caused rapid loss of DC progenitors, pDCs, and the cross-presenting cDC1 subset. Trim33-deficient Flt3+ progenitors up-regulated pro-inflammatory and macrophage-specific genes but failed to induce the DC differentiation program. Collectively, these data elucidate mechanisms that control Flt3L-driven differentiation of the entire DC lineage and identify Trim33 as its essential regulator.

FcRn regulates antigen presentation in dendritic cells downstream of DEC205-targeted vaccines

Dendritic cell (DC)-targeted vaccination is a new mode of antigen delivery that relies on the use of monoclonal antibodies (mAb) to target antigen to specific DC subsets. The neonatal Fc receptor (FcRn) is a non-classical Fc receptor that binds to immunoglobulin G (IgG) in acidified endosomes and controls its intracellular transport and recycling. FcRn is known to participate in the antigen presentation of immune complexes, however its contribution to DC-targeted vaccination has not previously been examined. Here we have investigated the role of FcRn in antigen presentation using antigen conjugated to IgG mAb which target specific DC receptors, including DEC205 and Clec9A expressed by the conventional DC 1 (cDC1) subset. We show that FcRn is expressed at high levels by cDC1, both at steady-state and following activation and plays a significant role in MHC I cross-presentation and MHC II presentation of antigens that are targeted to cDC1 via mAb specific for DEC205. This effect of FcRn is intrinsic to cDC1 and FcRn impacts the efficacy of anti-DEC205-mediated vaccination against B cell lymphoma. In contrast, FcRn does not impact presentation of antigens targeted to Clec9A and does not regulate presentation of cell-associated antigen. These data highlight a new and unique role of FcRn in controlling the immunogenicity of anti-DEC205-based vaccination, with consequences for exploiting this pathway to improve DC-targeted vaccine outcomes.

Abstract LB166: Discovery of CT3021, a novel potent adenosine A2a/A2b/A1 receptor triple antagonist

Abstract In a CD73-positive tumor microenvironment (TME), ATP released from apoptotic tumor cells converts to adenosine, generating an adenosine-rich immunosuppressive environment. Adenosine activates G-protein coupled receptors expressed on immune cells to achieve immune suppression, with a mechanism of action involving 1) dampening antitumor effector cells (T eff and NK cells) via adenosine engagement on A2a receptor, (2) reducing dendritic cell antigen presentation and promoting MDSC differentiation by activating A2b and A2a receptors, and (3) inducing chemotactic migration of immature plasmacytoid dendritic cells to infiltrate tumor tissue via A1 receptor. Furthermore, A1 receptor expression in certain tumors mediates an adenosine-driven tumor cell proliferation, likely through A1 receptor Gi coupling to the Hippo-YAP signal transduction pathway. Thus, pharmacologic inhibition of A2a, A2b, and A1 receptors by a triple antagonist in the context of adenosine-rich TME may represent an attractive strategy to achieve a better outcome in treating solid tumors. We discovered and characterized a novel adenosine receptor antagonist CT3021. CT3021 exhibits high binding affinity to A2a, A2b, and A1, with a Ki value of 0.37 nM, 1.76 nM, and 1.26 nM, respectively, and is selective against the A3 receptor and other 84 pharmacologically and/or toxicologically relevant targets. Schild analysis demonstrated that CT3021 is a competitive antagonist with a calculated KB value of 0.18 nM on A2a receptor in a whole cell cAMP assay in transfected HEK293 cells. In functional antagonist assays, CT3021 maintains its high potency full antagonism under an adenosine-rich TME-like condition (10-100 µM adenosine) both in transfected HEK293 cells and in isolated human T lymphocytes. CT3021 has a high oral bioavailability, a limited CNS exposure, and a favorable ADME profile. CT3021 is well tolerated in rats after repeat dosing. Further toxicology and efficacy studies are underway to explore the potential of CT3021 as a best-in-class adenosine receptor antagonist immunotherapy for the treatment of CD73 positive and A1 receptor positive solid tumors. Citation Format: Sandong Han, Nam Hee Kim, Hongmei He, Zhi Liang Chu. Discovery of CT3021, a novel potent adenosine A2a/A2b/A1 receptor triple antagonist [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB166.

Integrated Copper Nanomaterials‐Decorated Microsphere Photothermal Platform for Comprehensive Melanoma Treatment

Patients who undergo resection for melanoma face challenges, such as delayed healing and radiation dermatitis. Moreover, incomplete tumor resection is a key factor contributing to poor prognosis and increased recurrence rates. However, a therapeutic platform that can effectively prevent tumor recurrence and promote wound healing remains a challenge. Hence, a pioneering approach is presented using melanoma‐derived cancer cell membrane (CM) as a tumor antigen to encapsulate copper (Cu)‐based metal‐organic framework (MOF) nanomaterials to fabricate nanomaterials termed MOF@CM. Then MOF@CM is adsorbed onto polydopamine (PDA)‐modified poly lactic‐co‐glycolic acid (PLGA) porous microspheres (PLGA/PDA) to develop the copper nanomaterials‐decorated microspheres termed PLGA/PDA‐CCM (PLGA/PDA loaded with CM‐coated MOF). It exerts homologous tumor targeting and photothermal effects, inducing immunogenic cell death. Simultaneously, the sustained release of MOF@CM shows enhanced antigen presentation in dendritic cells (DCs) with the help of CpG, and induces DC maturation and activated immune responses, acting as an effective vaccine to prevent tumor recurrence. The platform harnesses the combined advantages of the local thermal effect and the presence of a Cu‐based MOF, which endow antibacterial properties and stimulate angiogenesis, thereby facilitating wound healing and mitigating radiation dermatitis. This integrated microsphere treatment platform represents a promising strategy for addressing melanoma.

Preparation and characterization of curdlan-chitosan conjugate nanoparticles as mucosal adjuvants for intranasal influenza H1N1 subunit vaccine

Intranasal vaccination offers crucial protection against influenza virus pandemics. However, antigens, especially subunit antigens, often fail to induce effective immune responses without the help of immune adjuvants. Our research has demonstrated that a polyelectrolyte complex, composed of curdlan sulfate/O-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (CS/O-HTCC), effectively triggers both mucosal and systemic immune responses when administrated intranasal. In this study, stable nanoparticles formed by curdlan-O-HTCC conjugate (CO NP) were prepared and characterized. Furthermore, the efficacy of CO NP was evaluated as a mucosal adjuvant in an intranasal influenza H1N1 subunit vaccine. The results revealed that CO NP exhibits uniform and spherical morphology, with a size of 190.53 ± 4.22 nm, and notably, it remains stable in PBS at 4 °C for up to 6 weeks. Biological evaluation demonstrated that CO NP stimulates the activation of antigen-presenting cells (APCs), including macrophages and dendritic cells (DCs), both in vitro and in vivo. Furthermore, intranasal administration of CO NP effectively elicits cellular and humoral immune responses, notably enhancing mucosal immunity. Thus, CO NP emerges as a promising mucosal adjuvant for influenza subunit vaccines.

Mesenchymal stem cell transplantation may be able to induce immunological tolerance in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a common, potentially fatal autoimmune disease involving a significant inflammatory response. SLE is characterised by failure of self-tolerance and activation of autoreactive lymphocytes, leading to persistent disease. Although current treatments achieve some improvement in patients, some SLE patients are refractory and others relapse after drug withdrawal. The toxicity of current drug regimens, with recurrent infections, together with ongoing inflammation, contribute significantly to the progressive decline in organ function. Therefore, the clinical management of SLE requires more effective and less toxic treatments, ideally inducing complete remission and self-tolerance. In this context, recently developed cell therapies based on mesenchymal stem cells (MSCs) represent a promising and safe strategy in SLE. MSCs inhibit the activation of B cells, prevent the differentiation of CD4⁺ T cells into autoreactive T cells, reprogram macrophages with anti-inflammatory effects and inhibit dendritic cells (DCs), limiting their activity as antigen-presenting cells. In addition, MSCs could induce antigen-specific tolerance by enhancing anergy processes in autoreactive cells - by inhibiting the maturation of antigen-presenting DCs, blocking the T cell receptor (TcR) pathway and secreting inhibitory molecules -, increasing apoptotic activity to eliminate them, and activating regulatory T cells (Tregs) to enhance their proliferation and induction of tolerogenic DCs. Thus, induction of self-tolerance leads to immune balance, keeping inflammation under control and reducing lupus flares.

Probiotic lactic acid bacteria promote anti-tumor immunity through enhanced major histocompatibility complex class I-restricted antigen presentation machinery in dendritic cells.

Lactic acid bacteria (LAB) possess the ability to argument T cell activity through functional modification of antigen presenting cells (APCs), such as dendritic cells (DCs) and macrophages. Nevertheless, the precise mechanism underlying LAB-induced enhancement of antigen presentation in APCs remains incompletely understood. To address this question, we investigated the detailed mechanism underlying the enhancement of major histocompatibility complex (MHC) class I-restricted antigen presentation in DCs using a probiotic strain known as Lactococcus lactis subsp. Cremoris C60. We found that Heat-killed-C60 (HK-C60) facilitated the processing and presentation of ovalbumin (OVA) peptide antigen OVA257-264 (SIINFEKL) via H-2Kb in bone marrow-derived dendritic cells (BMDCs), leading to increased generation of effector CD8+ T cells both in vitro and in vivo. We also revealed that HK-C60 stimulation augmented the activity of 20S immunoproteasome (20SI) in BMDCs, thereby enhancing the MHC class I-restricted antigen presentation machinery. Furthermore, we assessed the impact of HK-C60 on CD8+ T cell activation in an OVA-expressing B16-F10 murine melanoma model. Oral administration of HK-C60 significantly attenuated tumor growth compared to control treatment. Enhanced Ag processing and presentation machineries in DCs from both Peyer's Patches (PPs) and lymph nodes (LNs) resulted in an increased tumor antigen specific CD8+ T cells. These findings shed new light on the role of LAB in MHC class-I restricted antigen presentation and activation of CD8+ T cells through functional modification of DCs.

Abstract 3922: Quaking modulates anti-tumor immunity by regulating antigen processing and presentation in dendritic cells

Abstract Dendritic cells are essential players in anti-tumor immunity. One of their critical roles is to process and present tumor associated antigens to T cells, thereby inducing antigen-specific T cell response. However, cellular factors and molecular pathways regulating antigen processing and presentation by DCs are not fully understood.Here, we revealed a potential regulatory role of a transcriptional co-activator, Quaking (QKI), and its binding partner, PPARδ in antigen processing and presentation by DCs. Consistent with our previous studies in neural stem cells and microglia, we found QKI and PPARδ enhance phagocytosis in DCs by upregulating genes involved in the formation of phagosome and endosomes. QKI- or PPARδ-deficient DCs showed reduced CD8+ T cell priming capacity in vitro. In vivo tumor models suggested DC-specific knocking out of QKI or PPARδ promoted the tumor growth. Furthermore, ablation of QKI or PPARδ in DCs limited the effectiveness of immune checkpoint blockade in multiple tumor models.Together, these revealed a transcriptional regulation of antigen processing and presentation by DCs through QKI and PPARδ. Our data also suggested that perturbing this important function of DC would subvert their anti-tumor activity, highlighting the pivotal role of DCs in an effective anti-tumor immune response. Citation Format: Yating Li, Jian Hu, Cassian Yee. Quaking modulates anti-tumor immunity by regulating antigen processing and presentation in dendritic cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3922.

Abstract 709: Enhancing prostate cancer treatment: Synergistic effects of mechano-thermal focused ultrasound and radiation therapy

Abstract Current treatments for prostate cancer primarily rely on radiation and hormone deprivation therapy, yet they often lack effective immunotherapeutic effects. Furthermore, long-term hormone ablation has side effects, such as, impotency and osteoporosis. Addressing this gap, we introduce an innovative dual-frequency focused ultrasound (FUS) platform for non-ablative focal therapy, which induces protein unfolding, ER stress, and increases heat-shock protein expression along with translocation of endoplasmic reticular chaperone proteins (e.g., calreticulin) on the tumor cell surface, thereby sensitizing them for phagocytosis by dendritic cells for efficient antigen presentation and cross priming. We hypothesized that FUS-mediated acoustic immune priming can be combined with ablative therapies, such as, hormone ablation and/or radiation therapy (RT) for induction of tumor-specific adaptive immune response and better tumor control than monotherapy in murine prostate cancer models. Utilizing murine prostate cancer cell lines, MyC-CaP and RM1, we explored the cellular responses to androgen deprivation, observing distinct sensitivities. Twenty-four hours after FUS treatment tumor cells experienced mechano-thermal stress response with 15-fold increase in Hspa1a expression. Transmission Electron Microscopy studies showed formation of myelin figures, nuclear membrane deformation, and lipid droplet formation. In vivo, the combination of FUS (220w/cm2 intensity for 3 sec at focal point) and RT (8-10 Gy daily x two fractions) markedly delayed tumor growth and achieved complete cure in 14-17% of animals. Through multicolor flow cytometry, we detected significant alterations in the immune microenvironment, including increased CD8+ T cell infiltration and reduced tumor-associated macrophages in the tumor bed. However, we also observed a compensatory rise in pro-tumor immune cells such as PMN-MDSCs and Tregs with significant suppression of eosinophils (p<0.05). Interestingly, there was suppression of splenic PMN-MDSCs, Mo-MDSCs, and tumor draining lymph node macrophages, suggesting systemic immune modulation in peripheral lymphoid organs of FUS+RT-treated tumor-bearing animals. Our findings reveal that the combination therapy of FUS and RT improves tumor control in murine prostate cancer and significantly modulates the systemic and tumor immune microenvironment. This approach offers new avenues for immunotherapy, potentially transforming the treatment landscape for prostate cancer, typically resistant to conventional immunotherapeutic strategies. Citation Format: Soumya Chatterjee, Saurabh Singh, Stephen Barry, Chandan Guha. Enhancing prostate cancer treatment: Synergistic effects of mechano-thermal focused ultrasound and radiation therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 709.

Immune tolerance and the prevention of autoimmune diseases essentially depend on thymic tissue homeostasis.

The intricate balance of immune reactions towards invading pathogens and immune tolerance towards self is pivotal in preventing autoimmune diseases, with the thymus playing a central role in establishing and maintaining this equilibrium. The induction of central immune tolerance in the thymus involves the elimination of self-reactive T cells, a mechanism essential for averting autoimmunity. Disruption of the thymic T cell selection mechanisms can lead to the development of autoimmune diseases. In the dynamic microenvironment of the thymus, T cell migration and interactions with thymic stromal cells are critical for the selection processes that ensure self-tolerance. Thymic epithelial cells are particularly significant in this context, presenting self-antigens and inducing the negative selection of autoreactive T cells. Further, the synergistic roles of thymic fibroblasts, B cells, and dendritic cells in antigen presentation, selection and the development of regulatory T cells are pivotal in maintaining immune responses tightly regulated. This review article collates these insights, offering a comprehensive examination of the multifaceted role of thymic tissue homeostasis in the establishment of immune tolerance and its implications in the prevention of autoimmune diseases. Additionally, the developmental pathways of the thymus are explored, highlighting how genetic aberrations can disrupt thymic architecture and function, leading to autoimmune conditions. The impact of infections on immune tolerance is another critical area, with pathogens potentially triggering autoimmunity by altering thymic homeostasis. Overall, this review underscores the integral role of thymic tissue homeostasis in the prevention of autoimmune diseases, discussing insights into potential therapeutic strategies and examining putative avenues for future research on developing thymic-based therapies in treating and preventing autoimmune conditions.

Dendritic cell-targeted delivery of antigens using extracellular vesicles for anti-cancer immunotherapy.

Neoantigen delivery using extracellular vesicles (EVs) has gained extensive interest in recent years. EVs derived from tumour cells or immune cells have been used to deliver tumour antigens or antitumor stimulation signals. However, potential DNA contamination from the host cell and the cost of large-scale EV production hinder their therapeutic applications in clinical settings. Here, we develop an antigen delivery platform for cancer vaccines from red blood cell-derived EVs (RBCEVs) targeting splenic DEC-205+ dendritic cells (DCs) to boost the antitumor effect. By loading ovalbumin (OVA) protein onto RBCEVs and delivering the protein to DCs, we were able to stimulate and present antigenic OVA peptide onto major histocompatibility complex (MHC) class I, subsequently priming activated antigen-reactive T cells. Importantly, targeted delivery of OVA using RBCEVs engineered with anti-DEC-205 antibody robustly enhanced antigen presentation of DCs and T cell activation. This platform is potentially useful for producing personalised cancer vaccines in clinical settings.

Lymph-targeted high-density lipoprotein-mimetic nanovaccine for multi-antigenic personalized cancer immunotherapy.

Cancer vaccines show huge potential for cancer prevention and treatment. However, their efficacy remains limited due to weak immunogenicity regarding inefficient stimulation of cytotoxic T lymphocyte (CTL) responses. Inspired by the unique characteristic and biological function of high-density lipoprotein (HDL), we here develop an HDL-mimicking nanovaccine with the commendable lymph-targeted capacity to potently elicit antitumor immunity using lipid nanoparticle that is co-loaded with specific cancer cytomembrane harboring a collection of tumor-associated antigens and an immune adjuvant. The nanoparticulate impact is explored on the efficiency of lymphatic targeting and dendritic cell uptake. The optimized nanovaccine promotes the co-delivery of antigens and adjuvants to lymph nodes and maintains antigen presentation of dendritic cells, resulting in long-term immune surveillance as the elevated frequency of CTLs within lymphoid organs and tumor tissue. Immunization of nanovaccine suppresses tumor formation and growth and augments the therapeutic efficacy of checkpoint inhibitors notably on the high-stemness melanoma in the mouse models.

Long-chain acyl-CoA synthetase 4-mediated mitochondrial fatty acid metabolism and dendritic cell antigen presentation.

This study aims to investigate the role of Acyl-CoA synthetase 4 (ACSL4) in mediating mitochondrial fatty acid metabolism and dendritic cell (DC) antigen presentation in the immune response associated with asthma. RNA sequencing was employed to identify key genes associated with mitochondrial function and fatty acid metabolism in DCs. ELISA was employed to assess the levels of fatty acid metabolism in DCs. Mitochondrial morphology was evaluated using laser confocal microscopy, structured illumination microscopy, and transmission electron microscopy. Flow cytometry and immunofluorescence were utilized to detect changes in mitochondrial superoxide generation in DCs, followed by immunofluorescence co-localization analysis of ACSL4 and the mitochondrial marker protein COXIV. Subsequently, pathological changes and immune responses in mouse lung tissue were observed. ELISA was conducted to measure the levels of fatty acid metabolism in lung tissue DCs. qRT-PCR and western blotting were employed to respectively assess the expression levels of mitochondrial-associated genes (ATP5F1A, VDAC1, COXIV, TFAM, iNOS) and proteins (ATP5F1A, VDAC1, COXIV, TOMM20, iNOS) in lung tissue DCs. Flow cytometry was utilized to analyze changes in the expression of surface antigens presented by DCs in lung tissue, specifically the MHCII molecule and the co-stimulatory molecules CD80/86. The sequencing results reveal that ACSL4 is a crucial gene regulating mitochondrial function and fatty acid metabolism in DCs. Inhibiting ACSL4 reduces the levels of fatty acid oxidases in DCs, increases arachidonic acid levels, and decreases A-CoA synthesis. Simultaneously, ACSL4 inhibition leads to an increase in mitochondrial superoxide production (MitoSOX) in DCs, causing mitochondrial rupture, vacuolization, and sparse mitochondrial cristae. In mice, ACSL4 inhibition exacerbates pulmonary pathological changes and immune responses, reducing the fatty acid metabolism levels within lung tissue DCs and the expression of mitochondria-associated genes and proteins. This inhibition induces an increase in the expression of MHCII antigen presentation molecules and co-stimulatory molecules CD80/86 in DCs. The research findings indicate that ACSL4-mediated mitochondrial fatty acid metabolism and dendritic cell antigen presentation play a crucial regulatory role in the immune response of asthma. This discovery holds promise for enhancing our understanding of the mechanisms underlying asthma pathogenesis and potentially identifying novel targets for its prevention and treatment.

Supramolecular Lipid Nanoparticles Based on Host-Guest Recognition: A New Generation Delivery System of mRNA Vaccines For Cancer Immunotherapy.

Dendritic cell (DC) maturation is a crucial process for antigen presentation and the initiation of T cell-mediated immune responses. Toll-like receptors play pivotal roles in stimulating DC maturation and promoting antigen presentation. Here, a novel message RNA (mRNA) cancer vaccine is reported that boosts antitumor efficacy by codelivering an mRNA encoding tumor antigen and a TLR7/8 agonist (R848) to DC using supramolecular lipid nanoparticles (SMLNP) as a delivery platform, in which a new ionizable lipid (N2-3L) remarkably enhances the translation efficiency of mRNA and a β-cyclodextrin (β-CD)-modified ionizable lipid (Lip-CD) encapsulates R848. The incorporation of R848 adjuvant into the mRNA vaccine through noncovalent host-guest complexation significantly promotes DC maturation and antigen presentation after vaccination, thus resulting in superior antitumor efficacy in vivo. Moreover, the antitumor efficacy is further boosted synergized with immune checkpoint blockade by potentiating the anticancer capability of cytotoxic T lymphocytes infiltrated in tumor sites. This work indicates that SMLNP shows brilliant potential as next-generation delivery system in the development of mRNA vaccines with high efficacy.