Dendritic Cells Research Articles

Ternary Schottky Junction for Sonocatalytic Water Splitting in Gas-Immunotherapy-Mediated Cancer Treatment.

Hydrogen therapy has shown new potential in cancer treatment, particularly in high-pressure and hypoxic areas, where it demonstrates the ability to alter the tumor microenvironment and regulate tumor metabolism. Hydrogen disrupts the mitochondrial function of cancer cells, interferes with their energy metabolism, and ultimately leads to energy depletion and apoptosis. In this study, a sonocatalyst (BPM), is designed to generate hydrogen and oxygen in situ within tumors, further enhancing the therapeutic efficacy. The mesocrystalline structure of BPM, composed of bismuth fluoride, polyoxometalates, and molybdenum carbide, significantly improves charge separation and electron transfer efficiency under ultrasound irradiation, resulting in an efficient water-splitting reaction. By simultaneously generating hydrogen and oxygen within the tumor microenvironment and depleting glutathione, BPM effectively triggers oxidative stress and alleviates hypoxia, thereby disrupting mitochondrial function and inhibiting energy metabolism in cancer cells. Additionally, BPM enhances antitumor immune responses by promoting dendritic cell maturation, activating T lymphocytes, and polarizing macrophages toward the M1 phenotype, reversing the immunosuppressive state of the tumor microenvironment. The results indicate that BPM holds potential for gas-immunotherapy combination treatments, offering a multifunctional strategy to improve cancer therapy outcomes.

Dendritic cell maturation in cancer.

Dendritic cells (DCs) are specialized antigen-presenting cells that are present at low abundance in the circulation and tissues; they serve as crucial immune sentinels by continually sampling their environment, migrating to secondary lymphoid organs and shaping adaptive immune responses through antigen presentation. Owing to their ability to orchestrate tolerogenic or immunogenic responses to a specific antigen, DCs have a pivotal role in antitumour immunity and the response to immune checkpoint blockade and other immunotherapeutic approaches. The multifaceted functions of DCs are acquired through a complex, multistage process called maturation. Although the role of inflammatory triggers in driving DC maturation was established decades ago, less is known about DC maturation in non-inflammatory contexts, such as during homeostasis and in cancer. The advent of single-cell technologies has enabled an unbiased, high-dimensional characterization of various DC states, including mature DCs. This approach has clarified the molecular programmes associated with DC maturation and also revealed how cancers exploit these pathways to subvert immune surveillance. In this Review, we discuss the mechanisms by which cancer disrupts DC maturation and highlight emerging therapeutic opportunities to modulate DC states. These insights could inform the development of DC-centric immunotherapies, expanding the arsenal of strategies to enhance antitumour immunity.

Corrigendum: The role of dendritic cells in tertiary lymphoid structures: implications in cancer and autoimmune diseases

Corrigendum: The role of dendritic cells in tertiary lymphoid structures: implications in cancer and autoimmune diseases

Metabolic deficiencies underlie reduced plasmacytoid dendritic cell IFN-I production following viral infection

Type I Interferons (IFN-I) are central to host protection against viral infections, with plasmacytoid dendritic cells (pDC) being the most significant source, yet pDCs lose their IFN-I production capacity following an initial burst of IFN-I, resulting in susceptibility to secondary infections. The underlying mechanisms of these dynamics are not well understood. Here we find that viral infection reduces the capacity of pDCs to engage both oxidative and glycolytic metabolism. Mechanistically, we identify lactate dehydrogenase B (LDHB) as a positive regulator of pDC IFN-I production in mice and humans; meanwhile, LDHB deficiency is associated with suppressed IFN-I production, pDC metabolic capacity, and viral control following infection. In addition, preservation of LDHB expression is sufficient to partially retain the function of otherwise exhausted pDCs, both in vitro and in vivo. Furthermore, restoring LDHB in vivo in pDCs from infected mice increases IFNAR-dependent, infection-associated pathology. Our work thus identifies a mechanism for balancing immunity and pathology during viral infections, while also providing insight into the highly preserved infection-driven pDC inhibition.

Perforin-2 is overexpressed in Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease (KFD) is a self-limited lymphadenopathy characterized by subcortical necrosis and paracortical proliferation of lymphocytes, histiocytes and plasmacytoid dendritic cells with abundant apoptosis. The etiology of KFD remains unknown. Perforin-2 is a highly conserved transmembrane molecule capable of forming pores following intercellular interaction with bacteria and erythrocytes. Perforin-2 is also essential for the activation of type I interferon-induced JAK/STAT signaling and elimination of virus infection. Herein, we hypothesized that perforin-2 or macrophage-expressed gene 1 (MPEG1) protein function is dysregulated in KFD, resulting in an exaggerated immune response, possibly following exposure to an unknown infectious agent. Twelve cases of KFD were the study group. We isolated total RNA from fixed, paraffin-embedded whole tissue sections. We also assessed primary human B-cells and 4 cases of reactive follicular hyperplasia as controls. Perforin-2 mRNA levels were assessed by quantitative real-time PCR (qRT-PCR). We found that perforin-2 mRNA expression was significantly upregulated in 11 of 12 (92%) KFD cases as compared with control samples. These results suggest that expression of perforin-2 is dramatically upregulated in KFD cases. Increased levels of perforin-2 likely explain the abundant apoptosis in KFD. These data also support the hypothesis that upregulation of perforin-2 may be part of the host immune reaction to an unknown infectious agent that is the trigger for KFD.

Obesity drives dysregulation in DC responses to viral infection

Abstract Introduction Obesity is a worldwide epidemic, with over 1 billion people worldwide living with obesity. It is associated with an increased risk of over 200 chronic co-morbidities, including an increased susceptibility to infection. Numerous studies have highlighted the dysfunction caused by obesity on a wide range of immune cell subsets, including dendritic cells (DCs). DCs are innate immune sentinels which bridge the innate and adaptive immune systems. DCs provide critical signals which instruct and shape the immune response. Our group has previously reported that DCs from people with obesity (PWO) display defective cytokine production, however the mechanisms underpinning these defects are unclear. Methods We investigated the functional responses of DCs using a murine-specific single-stranded RNA virus, Sendai virus (SeV), in mice on a standard diet and in a model of diet-induced obesity (DIO). Results Here, we demonstrate that GM-CSF cultured bone marrow-derived DCs (GM-DCs) from mice on a high fat diet (HFD) have reduced cytokine production following viral challenge. This was associated with a dysfunctional metabolism through reduced translation in the HFD GM-DCs. Conclusion We propose that obesity-mediated effects on DCs have downstream consequences on their ability to effectively mediate subsequent immune responses, especially during viral infection.

MAIT cells protect against sterile lung injury.

Mucosal-associated invariant T (MAIT) cells, the most abundant unconventional Tcells in the lung, can exhibit a wide range of functional responses to different triggers via their Tcell receptor (TCR) and/or cytokines. Their role, especially in sterile lung injury, is unknown. Using single-cell RNA sequencing (scRNA-seq), spectral analysis, and adoptive transfer in a bleomycin-induced sterile lung injury, we found that bleomycin activates murine pulmonary MAIT cells and is associated with a protective role against bleomycin-induced lung injury. MAIT cells drive the accumulation of type 1 conventional dendritic cells (cDC1s), limiting tissue damage in a DNGR-1-dependent manner. Human scRNA-seq data revealed that MAIT cells were activated, with increased cDC populations in idiopathic pulmonary fibrosis patients. Thus, MAIT cells enhance defense against sterile lung injury by fostering cDC1-driven anti-fibrotic pathways.

A covalent peptide-based lysosome-targeting protein degradation platform for cancer immunotherapy

The lysosome-targeting chimera (LYTAC) strategy provided a very powerful tool for the degradation of membrane proteins. However, the synthesis of LYTACs, antibody-small molecule conjugates, is challenging. The ability of antibody-based LYTACs to penetrate solid tumor is limited as well, especially to cross the blood-brain barrier (BBB). Here, we propose a covalent chimeric peptide-based targeted degradation platform (Pep-TACs) by introducing a long flexible aryl sulfonyl fluoride group, which allows proximity-enabled cross-linking upon binding with the protein of interest. The Pep-TACs platform facilitates the degradation of target proteins through the mechanism of recycling transferrin receptor (TFRC)-mediated lysosomal targeted endocytosis. Biological experiments demonstrate that covalent Pep-TACs can significantly degrade the expression of PD-L1 on tumor cells, dendritic cells and macrophages, especially under acidic conditions, and markedly enhance the function of T cells and tumor phagocytosis by macrophages. Furthermore, both in anti-PD-1-responsive and -resistant tumor models, the Pep-TACs exert significant anti-tumor immune response. It is noteworthy that Pep-TACs can cross the BBB and prolong the survival of mice with in situ brain tumor. As a proof-of-concept, this study introduces a modular TFRC-based covalent peptide degradation platform for the degradation of membrane protein, and especially for the immunotherapy of brain tumors.

Optimizing rWTC-MBTA Vaccine Formulations, Dosing Regimens, and Cryopreservation Techniques to Enhance Anti-Metastatic Immunotherapy

Metastatic cancer poses significant clinical challenges, necessitating effective immunotherapies with minimal systemic toxicity. Building on prior research demonstrating the rWTC-MBTA vaccine’s ability to inhibit tumor metastasis and growth, this study focuses on its clinical translation by optimizing vaccine composition, dosing regimens, and freezing techniques. The vaccine formula components included three TLR ligands (LTA, Poly I:C, and Resiquimod) and an anti-CD40 antibody, which were tested in melanoma and triple-negative breast cancer (TNBC) models. The formulations were categorized as rWTC-MBT (Mannan-BAM with LTA, Poly I:C, Resiquimod), rWTC-MBL (LTA), rWTC-MBP (Mannan-BAM with Poly I:C), and rWTC-MBR (Resiquimod). In the melanoma models, all the formulations exhibited efficacy that was comparable to that of the full vaccine, while in the “colder” TNBC models, the formulations with multiple TLR ligands or Resiquimod alone performed the best. Vaccine-induced activation of dendritic cell (DC) subsets, including conventional DCs (cDCs), myeloid DCs (mDCs), and plasmacytoid DCs (pDCs), was accompanied by significant CD80+CD86+ population induction, suggesting robust innate immune stimulation. An initial three-dose schedule followed by booster doses (3-1-1-1 or 3-3-3-3) reduced the metastatic burden effectively. Gradual freezing (DMSO-based preservation) maintained vaccine efficacy, underscoring the importance of intact cell structure. These findings highlight the potential of simplified formulations, optimized dosing, and freezing techniques in developing practical, scalable immunotherapies for metastatic cancers.

A Phase 2 Study of Sotigalimab, a CD40 Agonist Antibody, Plus Concurrent Chemoradiation as Neoadjuvant Therapy for Esophageal and Gastroesophageal Junction Cancers.

Neoadjuvant chemoradiation (NCRT) followed by surgical resection represents a standard approach for patients with locally advanced esophageal/GEJ cancers. Sotigalimab is a high affinity CD40 agonist antibody capable of inducing and expanding anti-tumor immune responses by activating dendritic cells, T and B lymphocytes, NK cells, and M1 macrophages. This study examined the safety and efficacy of combining sotigalimab with NCRT in patients with esophageal or GEJ cancers. Patients with resectable (T1-3, Nx) adenocarcinoma(AC) or squamous cell carcinoma(SCC) of the esophagus or GEJ were eligible. T1N0 and cervical tumors were excluded. Study treatment: weekly carboplatin/paclitaxel with concurrent radiation 5040 cGy plus 3-4 doses of sotigalimab prior to Ivor-Lewis esophagectomy. Primary efficacy endpoint was pathologic complete response (path CR) rate. 33 patients were enrolled (AC 76%, SCC 24%; clinical stage III 67%). Ninety percent of patients received all planned doses of sotigalimab. The most common adverse events attributed to sotigalimab were nausea, fever/chills, fatigue, and cytokine release syndrome (CRS); most of these were Grade 1-2. Grade >3 CRS was observed in 3 pts (9%). Twenty-five of the 29 efficacy-evaluable patients underwent an R0 resection (87.9%), with an overall path CR rate of 37.9% (11/29). Post-tumor samples demonstrated increased infiltration and activation of dendritic cells, monocytes, and cytotoxic T cells compared to baseline. Sotigalimab combined with NCRT for esophageal or GEJ cancers was generally well tolerated and achieved path CR rates that compare favorably to historical data and are promising for this treatment strategy. NCT03165994.

Deciphering adenosine signaling in hepatocellular carcinoma: pathways, prognostic models, and therapeutic implications.

Hepatocellular carcinoma (HCC) is a highly lethal cancer due to its aggressive nature and poor prognosis. Adenosine, a key metabolic regulator in the tumor microenvironment (TME), plays a crucial role in cancer progression. In this review, we first described adenosine triphosphate (ATP)-adenosine metabolism in the TME and summarize its effects on tumor growth, immune suppression, angiogenesis, and metastasis in HCC. Given the limited number of clinical studies on adenosine signaling in HCC, we conducted Lasso-Cox analysis using the TCGA-LIHC cohort to develop a prognostic risk model composed of eight adenosine signaling-related genes. This model stratified the patients into low- and high-risk groups, with Kaplan‒Meier survival analysis revealing poorer overall survival in the high-risk group. Additionally, differential gene expression analysis between the two groups identified 24 enriched signaling pathways for further investigation. Immune infiltration and single cell RNA-seq analyses revealed a correlation between adenosine and immunosuppressive activity in the TME, with a particularly strong association observed in macrophages, dendritic cells, and monocytes. Finally, we provided an overview of the advancements of antagonists that target adenosine receptors progress in both preclinical research and clinical trials. In conclusion, this review aims to deepen our understanding of the biological role of adenosine and highlights emerging therapeutic strategies that may improve treatment outcomes for HCC.

Sarcoidosis: molecular mechanisms and therapeutic strategies.

Sarcoidosis, a multisystemic granulomatous disease with unknown etiology, is characterized by formation of noncaseating granulomas, which can affect all organs. Recent studies have made outstanding achievement in understanding the pathology, etiology, genetics, and immune dysregulation involved in granuloma formation of sarcoidosis. Antigen stimulation in genetically predisposed individuals enhances the phagocytic activity of antigen-presenting cells, including macrophages and dendritic cells. CD4 + T cells initiate dysregulated immune responses and secrete significant quantities of inflammatory cytokines, including interleukin (IL)-2 and interferon-gamma (IFN-γ), which play a crucial role in modulating the aggregation and fusion of macrophages to form granulomas. The current therapeutic strategies focus on blocking the formation and spread of granulomas to protect organ function and alleviate symptoms. The efficacy of traditional treatments, such as glucocorticoids and immunosuppressants, has been confirmed in the management of sarcoidosis. Promising therapeutic agents encompass inhibitors of cytokines, like those targeting tumor necrosis factor (TNF)-α, as well as inhibitors of signaling pathways, such as Janus kinase (JAK) inhibitors, which exhibit favorable prospects for application. Although there has been progress in the identification of biomarkers for the diagnosis, prognosis, activity and severity of sarcoidosis, specific and sensitive biomarkers have yet to be identified. This review outlines recent advancements in the molecular mechanisms and therapeutic strategies for the sarcoidosis.

Integrative analysis of 5-methylcytosine associated signature in papillary thyroid cancer

Emerging evidence has indicated that m5C modification plays a vital role in cancer development. However, the function of m5C-lncRNAs in PTC has never been reported. This study aims to explore the regulation mechanism of m5C RNA methylation-related long noncoding RNAs (m5C-lncRNAs) in papillary thyroid cancer (PTC). Bioinformatics analysis was used to investigate the role of m5C-lncRNAs in the prognosis and tumor immune microenvironment of PTC. Subsequently, we preliminarily verified the regulation mechanisms of m5C-lncRNAs in vivo and in vitro experiments. A total of six m5C-lncRNAs and five immune cell types were selected to construct the risk score and immune risk score (IRS) model, respectively. Patients with a high-risk score had a worse prognosis and the ROC indicated a reliable prediction performance (AUC = 0.796). As expected, the ESTIMATE and immune scores were higher (P < 0.001) and the tumor purity (P < 0.05) was significantly lower in the low-risk subgroup. CIBERSORT analysis showed Tregs, M0 macrophages, dendritic cells resting, and eosinophils were positively correlated to the risk score. Moreover, the expression levels of PD-1, PD-L1, CTLA-4, TIM-3, LAG-3, and KLRB1 were lower in the high-risk subgroup. Importantly, patients in high-risk subgroup tended to have a better response to immunotherapy than those in low-risk subgroup (P = 0.022). Similar to the above risk score, the IRS model also showed favorable prognosis predictive performance (AUC = 0.764). An integrated nomogram combining risk score, IRS, and age exhibited good prognostic predictive performance. Additionally, we validate the downregulation of PPP1R12A-AS1 promotes proliferation and metastasis by activating the MAPK signaling pathway. Our research confirms that m5C-lncRNAs not only contribute to evaluating the prognosis of patients with PTC but also help predict immune cell infiltration and immunotherapy response.

NT5E (CD73) as a prognostic biomarker and therapeutic target associated with immune infiltration in lung adenocarcinoma

Lung adenocarcinoma (LUAD), the most common type of lung cancer, is a leading cause of cancer-related mortality. NT5E, an ecto-5’-nucleotidase enzyme, has been implicated in cancer progression, particularly in efferocytosis. Despite its potential involvement, the prognostic significance of NT5E and relationship with immune cell infiltration in LUAD have not been extensively explored. In this study, we performed a comprehensive analysis to elucidate the expression patterns of NT5E and its prognostic implications in LUAD using data from diverse public databases. Multiple computational algorithms, including CIBERSORT, ESTIMATE, and xCell, were employed to assess the correlation between NT5E expression and immune cell infiltration. We found that NT5E was significantly overexpressed at both the mRNA and protein levels in LUAD tissues. Elevated NT5E expression was significantly linked to multiple clinicopathological factors, including metastasis and pathological stage, and served as a strong predictor of poor prognosis in LUAD patients. Gene Set Enrichment Analysis (GSEA) indicated that NT5E plays a crucial role in regulating immune responses, as evidenced by differential gene expression associated with NT5E levels. A strong positive correlation was observed between NT5E expression and the presence of immune cells, including dendritic cells, macrophages, and CD4+ T cells, as well as the expression of various immune cell markers, suggesting that NT5E may influence the prognosis of LUAD patients by regulating immune cell infiltration. Additionally, drug sensitivity analysis highlights the potential of selumetinib and PD318088, both MEK1/2 inhibitors, to target NT5E in LUAD treatment, suggesting their use as single agents or in combination with other therapies. Collectively, these findings establish NT5E as a promising prognostic biomarker and therapeutic target in LUAD, particularly in the context of immune cell infiltration.

Differential resistance to nematode infection is associated with the genotype- and age-dependent pace of intestinal T cell homing

The resistance of inbred mice to nematode infections varies depending on the extent of protective Th2 responses. Here, we compared two mouse lines differing in resistance to infection with the enteric nematode Heligmosomoides polygyrus bakeri despite the similar instruction of GATA-3+ T effector cells. Resistant BALB/c mice rapidly recruited high numbers of Th2 cells to the gut within the 1-week time frame required for larval development in the intestinal submucosa. C57BL/6 mice failed in the optimal control of early nematode fitness, with mucosal Th2 response peaking after 2 weeks when the larvae had left the tissue and relocated to the gut lumen as adult worms. The faster homing of Th2 cells to the gut of BALB/c mice is related to the extensive expression of the chemokine receptor CCR9 in GATA-3+ cells and higher frequencies of aldehyde dehydrogenase expressing dendritic cells present in mesenteric lymph nodes. Furthermore, nematode-infected older BALB/c mice displayed impaired resistance due to delayed mucosal homing of effector cells, which synergized with more numerous Th2/1 hybrid cells acting as IFN-γ-dependent confounders of type 2 responses. Hence, the distinct kinetics of effector cell recruitment to the infected gut and the quality of GATA-3+ T cell responses contribute to the genotype- and age-dependent resistance to intestinal nematode infections.

Autologous Human Dendritic Cells from XDR-TB Patients Polarize a Th1 Response Which Is Bactericidal to Mycobacterium tuberculosis

Extensively drug-resistant tuberculosis (XDR-TB) is a public health concern as drug resistance is outpacing the drug development pipeline. Alternative immunotherapeutic approaches are needed. Peripheral blood mononuclear cells (PBMCs) were isolated from pre-XDR/XDR-TB (n = 25) patients and LTBI (n = 18) participants. Thereafter, monocytic-derived dendritic cells (mo-DCs) were co-cultured with M. tb antigens, with/without a maturation cocktail (interferon-γ, interferon-α, CD40L, IL-1β, and TLR3 and TLR7/8 agonists). Two peptide pools were evaluated: (i) an ECAT peptide pool (ESAT6, CFP10, Ag85B, and TB10.4 peptides) and (ii) a PE/PPE peptide pool. Sonicated lysate of the M. tb HN878 strain served as a control. Mo-DCs were assessed for DC maturation markers, Th1 cytokines, and the ability of the DC-primed PBMCs to restrict the growth of M. tb-infected monocyte-derived macrophages. In pre-XDR/XDR-TB, mo-DCs matured with M. tb antigens (ECAT or PE/PPE peptide pool, or HN878 lysate) + cocktail, compared to mo-DCs matured with M. tb antigens only, showed higher upregulation of co-stimulatory molecules and IL-12p70 (p &lt; 0.001 for both comparisons). The matured mo-DCs had enhanced antigen-specific CD8+ T-cell responses to ESAT-6 (p = 0.05) and Ag85B (p = 0.03). Containment was higher with mo-DCs matured with the PE/PPE peptide pool cocktail versus mo-DCs matured with the PE/PPE peptide pool (p = 0.0002). Mo-DCs matured with the PE/PPE peptide pool + cocktail achieved better containment than the ECAT peptide pool + cocktail [50%, (IQR:39–75) versus 46%, (IQR:15–62); p = 0.02]. In patients with pre-XDR/XDR-TB, an effector response primed by mo-DCs matured with an ECAT or PE/PPE peptide pool + cocktail was capable of restricting the growth of M. tb in vitro

AIM2 Targeting of Nuclear DNA Leakage in Dendritic Cells Exacerbates Vasculitis in a Murine Model of Kawasaki Disease.

Kawasaki disease (KD) is an acute vasculitis that mostly affects children and is characterized by inflammation of medium-sized arteries, particularly the coronary arteries. The absent in melanoma 2 (AIM2) inflammasome senses cytosolic dsDNA and regulates IL-1β-driven inflammation. We investigated the role of AIM2 in Candida albicans water-soluble fraction (CAWS)-induced vasculitis in a murine model mimicking KD. Aim2-/- mice exhibited reduced vasculitis, inflammatory cell infiltration, and vascular fibrosis in the aorta and coronary arteries. In addition, dsDNA damage was detected in Dectin-2+ cells infiltrating vasculitis areas. In vitro experiments showed that CAWS induced dsDNA damage in Dectin-2+ bone marrow-derived dendritic cells (BMDC) isolated from wild-type (WT) and Aim2-/- mice. Furthermore, CAWS induces nuclear membrane deformation and DNA leakage into the cytosol, leading to AIM2 inflammasome activation and subsequent IL-1β production in WT BMDC. These findings suggest that AIM2 inflammasome activation in dendritic cells, triggered by dsDNA damage and leakage, contributes to the development of CAWS-induced vasculitis, and provides important insights into the inflammatory mechanisms underlying KD.

CD4 expression controls epidermal stem cell balance

The balance of stem cell populations is essential for the maintenance, renewal, and repair of the mammalian epidermis. Here, we report that CD4, which is a typical marker of helper T cells, monocytes, macrophages, and dendritic cells, is also expressed on murine K5+ keratinocytes. Lineage tracing of CD4+ cells reveals that their epidermal progeny has self-renewal abilities and clonogenic potential. The progeny of CD4+ epidermal cells contributes to epidermal renewal and progressively colonizes the interfollicular epidermis and hair follicles with age, thereby developing to all epidermal lineages. Wound healing studies furthermore show that the progeny of CD4+ epidermal cells accumulates at wound sites. Finally, using CD4 knockout mice we demonstrate that CD4 expression is essential for maintaining fast-cycling epidermal stem cells during homeostasis and that CD4 loss mitigates the age-related decline in wound repair capacity. Collectively, our data support the conclusion that CD4 expression is required for long-term maintenance of the epidermal stem cell balance.

Pre-injection of exosomes can significantly suppress ovarian cancer growth by activating the immune system in mice

As a type of “cold tumor” with limited immune cell infiltration, ovarian cancer has historically shown limited efficacy in immunotherapy. In this study, we report that exosomes from ovarian cancer can specifically target omentum which is the predilection site for ovarian cancer to metastasize and combat subsequently implanted tumor. Furthermore, we found a substantial increase in the proportion of CD3 + T cells, particularly CD8 + T cells, within the omental tissue where exosomes homed. This increase was accompanied by a significant enhancement in granzyme B levels within CD8 + T cells. Additionally, there was a notable elevation in the concentration of interferon-gamma (IFN-γ) in peripheral blood. In vitro results indicated that exosomes could be internalized by dendritic cells (DCs), promote DC differentiation, and subsequently induce the production of granzyme B and IFN-γ in T cells. Surprisingly, we also observed high expression of programmed death ligand 1 (PD-L1) in the omentum. Therefore, we discovered whether combining PD-L1 blockade led to further tumor regression. However, although the combination group showed complete tumor regression, this difference did not reach statistical significance. But in general, we emphasize that in the case of pre-injection, exosomes have great potential to combat the famous “cold tumor”, ovarian cancer, via targeting omentum and activating anti-tumor immunity, offering a novel avenue for overcoming ovarian cancer.

Regulation of IL-10 production in dendritic cells is controlled by the co-activation of TLR2 and Mincle by Lactiplantibacillus plantarum OLL2712.

We showed that Lactiplantibacillus plantarum OLL2712 (OLL2712) strongly induces interleukin (IL)-10 production in immune cells. Although beneficial effects of this strain have been observed in both mice and humans, the mechanisms underlying IL-10 induction remain unclear. In this study, we found that OLL2712 co-activates two pattern recognition receptors, leading to IL-10 production in the mouse-derived thermosensitive dendritic cell line, tsDC. We first revealed the involvement of the Toll-like receptor (TLR)2-Myeloid differentiation primary response gene (MYD) 88 pathway in OLL2712-induced IL-10 production in tsDCs. However, stimulation with the TLR2 agonist alone was insufficient to induce IL-10 production. Consequently, we explored additional signaling pathways and found that the phosphorylation of spleen tyrosine kinase (Syk) was important in response to OLL2712, which was not triggered by a TLR2 agonist alone. Notably, the activation of Syk was found to depend on macrophage-inducible C-type lectin receptor (Mincle), one of the C-type lectin receptors. However, the surface-expressed Mincle is not responsible for the IL-10 production by OLL2712. Instead, it depends on the incorporation of OLL2712 into tsDCs, suggesting that Mincle recognizes incorporated OLL2712 intracellularly. In summary, OLL2712 is initially recognized by TLR2, which subsequently induces the expression of Mincle to recognize incorporated OLL2712, ultimately inducing IL-10 production.IMPORTANCEThe objective of this study is to elucidate the mechanism by which Lactiplantibacillus plantarum OLL2712 (OLL2712), previously identified by our research group as a potent stimulator of interleukin-10 production in immune cells, exerts its immunomodulatory effects. Our findings indicate that OLL2712 acts in synergy with two pattern-recognition receptors: Toll-like receptor 2 and Macrophage inducible C-type lectin receptor (Mincle). Additionally, we observed that OLL2712 needs to be internalized intracellularly to be recognized by Mincle. These findings represent the first insights into the detailed mechanism underlying the anti-inflammatory effects of OLL2712.