Role of IL-6 in dendritic cell functions

Prophylactic and therapeutic cancer vaccine with continuous localized immunomodulation

Selective in vivo immune cell manipulation offers a promising strategy for cancer vaccines. In this context, spatiotemporal control over recruitment of specific cells, and their direct exposure to appropriate immunoadjuvants and antigens are key to effective cancer vaccines. We present an implantable 3D-printed cancer vaccine platform called the 'NanoLymph' that enables spatiotemporally-controlled recruitment and manipulation of immune cells in a subcutaneous site. Leveraging two reservoirs each for continuous immunoadjuvant release or antigen presentation, the NanoLymph attracts dendritic cells (DCs) on site and exposes them to tumor-associated antigens. Upon local antigen-specific activation, DCs are mobilized to initiate a systemic immune response. NanoLymph releasing granulocyte-macrophage colony-stimulating factor and CpG-oligodeoxynucleotides with irradiated whole cell tumor lysate inhibited tumor growth of B16F10 murine melanoma in a prophylactic and therapeutic vaccine setting. Overall, this study presents the NanoLymph as a versatile cancer vaccine development platform with replenishable and controlled local release of antigens and immunoadjuvants.

Periostracum Cicadae exhibits immunosuppressive effects on dendritic cells and contact hypersensitivity responses

ETHNOPHARMACOLOGICAL RELEVANCE

Periostracum Cicadae (PC), the molted exoskeleton of the cicada Cryptotympana pustulata Fabricius, is frequently employed in Chinese herbal medicine. Based on traditional therapies and pharmacological studies, PC appears to have immunomodulatory activity. However, the specific impact of PC on immunomodulation, particularly its effect on dendritic cells (DCs), remains unknown. DCs act professionally as antigen-presenting cells that trigger adaptive immune responses, making them critical for immunomodulation.

MATERIALS AND METHODS

The DCs derived from mouse bone marrow were used to examine the suppressive effect of PC extract on DC activation and maturation. The in vivo suppressive effect was evaluated using a mouse model of contact hypersensitivity (CHS) responses. The determination of the substances in the sample was performed by Liquid chromatography-mass spectrometry/mass spectrometry.

RESULTS

The ethyl acetate extract of PC (PCEA) significantly decreased the expressions of proinflammatory cytokines (IL-12, interleukin [IL]-6, as well as tumor necrosis factor [TNF]-α) and surface markers CD80 and CD86 in lipopolysaccharide-stimulated DCs. In the 2,4-dinitro-1-fluorobenzene-induced CHS mouse model, PCEA treatment dramatically attenuated the severity of symptoms. This was evidenced by the alleviation of ear swelling and a reduction in the count of infiltrating CD3+ T cells in the tested ears. In addition, N-acetyldopamine dimer and trimer were identified as major components.

CONCLUSION

This study is the first to show that components derived from PCEA inhibit the activation and maturation of DCs as well as CHS responses, indicating they have the potential for treating delayed-type hypersensitivity or DC-related immune disorders.

Dendritic Cells Pulsed with HAM/TSP Exosomes Sensitize CD4 T Cells to Enhance HTLV-1 Infection, Induce Helper T-Cell Polarization, and Decrease Cytotoxic T-Cell Response

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a progressive demyelinating disease of the spinal cord due to chronic inflammation. Hallmarks of disease pathology include dysfunctional anti-viral responses and the infiltration of HTLV-1-infected CD4+ T cells and HTLV-1-specific CD8+ T cells in the central nervous system. HAM/TSP individuals exhibit CD4+ and CD8+ T cells with elevated co-expression of multiple inhibitory immune checkpoint proteins (ICPs), but ICP blockade strategies can only partially restore CD8+ T-cell effector function. Exosomes, small extracellular vesicles, can enhance the spread of viral infections and blunt anti-viral responses. Here, we evaluated the impact of exosomes isolated from HTLV-1-infected cells and HAM/TSP patient sera on dendritic cell (DC) and T-cell phenotypes and function. We observed that exosomes derived from HTLV-infected cell lines (OSP2) elicit proinflammatory cytokine responses in DCs, promote helper CD4+ T-cell polarization, and suppress CD8+ T-cell effector function. Furthermore, exosomes from individuals with HAM/TSP stimulate CD4+ T-cell polarization, marked by increased Th1 and regulatory T-cell differentiation. We conclude that exosomes in the setting of HAM/TSP are detrimental to DC and T-cell function and may contribute to the progression of pathology with HTLV-1 infection.

Design, synthesis and anti-inflammatory assessment of certain substituted 1,2,4-triazoles bearing tetrahydroisoquinoline scaffold as COX 1/2-inhibitors

Aiming to discover effective and safe non-steroidal anti-inflammatory agents, a new set of 1,2,4-triazole tetrahydroisoquinoline hybrids 9a-g, 11a-g and 12a-g was synthesized and evaluated as inhibitors of COX-1 and COX-2. In order to overcome the adverse effects of highly selective COX-2 and non-selective COX-2 inhibitors, the compounds of this study were designed with the goal of obtaining moderately selective COX-2 inhibitors. In this study compounds 9e, 9g and 11f are the most effective derivatives against COX-2 with IC50 values 0.87, 1.27 and 0.58 µM, respectively which are better than or comparable to the standard drug celecoxib (IC50 = 0.82 µM) but with lower selectivity indices as required by our goal design. The results of the in vivo anti-inflammatory inhibition test revealed that compounds 9e, 9g and 11f displayed a higher significant anti-inflammatory activity than celecoxib at all-time intervals. In addition, these compounds significantly decreased the production of inflammatory mediators PGE-2, TNF-ɑ and IL-6. Compounds 9e, 9g and 11f had a safe gastric profile compared to indomethacin, also compound 11f (ulcerogenic index = 1.33) was less ulcerous than the safe celecoxib (ulcerogenic index = 3). Moreover, histopathological investigations revealed a normal architecture of both paw skin and gastric mucosa after oral treatment of rats with compound 11f. Furthermore, molecular docking studies were performed on COX-1 and COX-2 to study the binding pattern of compounds 9e, 9g and 11f on both isoenzymes.

Induced pluripotent stem cell-derived mesenchymal stem cells reverse bleomycin-induced pulmonary fibrosis and related lung stiffness

Idiopathic pulmonary fibrosis (IPF) is characterised by lung scarring and stiffening, for which there is no effective cure. Based on the immunomodulatory and anti-fibrotic effects of induced pluripotent stem cell (iPSC) and mesenchymoangioblast-derived mesenchymal stem cells (iPSCs-MSCs), this study evaluated the therapeutic effects of iPSCs-MSCs in a bleomycin (BLM)-induced model of pulmonary fibrosis. Adult male C57BL/6 mice received a double administration of BLM (0.15 mg/day) 7-days apart and were then maintained for a further 28-days (until day-35), whilst control mice were administered saline 7-days apart and maintained for the same time-period. Sub-groups of BLM-injured mice were intravenously-injected with 1×106 iPSC-MSCs on day-21 alone or on day-21 and day-28 and left until day-35 post-injury. Measures of lung inflammation, fibrosis and compliance were then evaluated. BLM-injured mice presented with lung inflammation characterised by increased immune cell infiltration and increased pro-inflammatory cytokine expression, epithelial damage, lung transforming growth factor (TGF)-β1 activity, myofibroblast differentiation, interstitial collagen fibre deposition and topology (fibrosis), in conjunction with reduced matrix metalloproteinase (MMP)-to-tissue inhibitor of metalloproteinase (TIMP) ratios and dynamic lung compliance. All these measures were ameliorated by a single or once-weekly intravenous-administration of iPSC-MSCs, with the latter reducing dendritic cell infiltration and lung epithelial damage, whilst promoting anti-inflammatory interleukin (IL)-10 levels to a greater extent. Proteomic profiling of the conditioned media of cultured iPSC-MSCs that were stimulated with TNF-α and IFN-γ, revealed that these stem cells secreted protein levels of immunosuppressive factors that contributed to the anti-fibrotic and therapeutic potential of iPSCs-MSCs as a novel treatment option for IPF.

Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Contextual AI models for single-cell protein biology

Understanding protein function and developing molecular therapies require deciphering the cell types in which proteins act as well as the interactions between proteins. However, modeling protein interactions across biological contexts remains challenging for existing algorithms. Here we introduce PINNACLE, a geometric deep learning approach that generates context-aware protein representations. Leveraging a multiorgan single-cell atlas, PINNACLE learns on contextualized protein interaction networks to produce 394,760 protein representations from 156 cell type contexts across 24 tissues. PINNACLE's embedding space reflects cellular and tissue organization, enabling zero-shot retrieval of the tissue hierarchy. Pretrained protein representations can be adapted for downstream tasks: enhancing 3D structure-based representations for resolving immuno-oncological protein interactions, and investigating drugs' effects across cell types. PINNACLE outperforms state-of-the-art models in nominating therapeutic targets for rheumatoid arthritis and inflammatory bowel diseases and pinpoints cell type contexts with higher predictive capability than context-free models. PINNACLE's ability to adjust its outputs on the basis of the context in which it operates paves the way for large-scale context-specific predictions in biology.

PGE2 induced miR365/IL-6/STAT3 signaling mediates dendritic cell dysfunction in cancer

AIM

To understand the mechanism of prostaglandin E2 (PGE2)-mediated immunosuppression in dendritic cells (DCs).

MAIN METHODS

In vivo experiments were conducted on 4T1 tumor bearing mice (TBM). In vitro experiments were performed in bone marrow-derived DCs (BMDCs), or spleen cells. Cytokines were monitored by ELISA/ELIspot. Gene expression was monitored by RT-PCR/flow cytometry.

KEY FINDINGS

In silico, in vitro, and in vivo experiments in 4T1 TBM revealed that PGE2 induced IL-6/pSTAT3 signaling through EP4 receptors in DCs, resulting in their dysfunction. These effects were reversed by EP4 antibody neutralization, EP4 antagonist, and STAT3 inhibitory peptides. PGE2 induced IL-6 was regulated by miR-365, as its mimic inhibited PGE2 induced IL-6 and the inhibitor increased lL-6 levels in DC. Bio-informatic analysis in human mammary cancers also revealed a strong compared co-relation between PGE2 and IL-6 (Correlation AnalyzeR) (R = 0.94). Mice bearing PTGS-2 KD 4T1 tumors had decreased tumor burden, PGE2, EP4, IL-6, and pSTAT3 signaling, along with improved DCs and T cell functions. Treatment of mice with a cyclooxygenase-2 (COX-2) inhibitor or EP4 antagonist decreased tumor burden, and this effect of EP4 antagonist was abrogated upon in vivo depletion of CD11c cells, indicating the crucial role of PGE2 signaling in DCs in tumor progression.

SIGNIFICANCE

In summary, our data highlights the importance of dendritic cells in mediating PGE2-mediated immunosuppression and the use of EP4 or STAT3 inhibitors or miR365 mimics can restore immunogenicity in cancer.

Clara cell 10 (CC10) protein attenuates allergic airway inflammation by modulating lung dendritic cell functions

Allergic asthma is a complex inflammatory disorder predominantly orchestrated by T helper 2 (Th2) lymphocytes. The anti-inflammatory protein Clara Cell 10-kDa (CC10), also known as secretoglobin family 1A member 1 (SCGB1A1), shows promise in modulating respiratory diseases. However, its precise role in asthma remains unclear. This study examines the potential of CC10 to suppress allergic asthma inflammation, specifically assessing its regulatory effects on Th2 cell responses and dendritic cells (DCs). Lower CC10 levels in asthma were observed and correlated with increased IgE and lymphocytes. Cc10-/- mice exhibited exacerbated allergic airway inflammation marked by increased inflammatory cell infiltration, Th2 cytokines, serum antigen-specific IgE levels, and airway hyperresponsiveness (AHR) in house dust mite (HDM)-induced models. Conversely, recombinant CC10 significantly attenuated these inflammatory responses. Intriguingly, CC10 did not directly inhibit Th cell activation but significantly downregulated the population of CD11b+CD103- DCs subsets in lungs of asthmatic mice and modulated the immune activation functions of DCs through NF-κB signaling pathway. The mixed lymphocyte response assay revealed that DCs mediated the suppressive effect of CC10 on Th2 cell responses. Collectively, CC10 profoundly mitigates Th2-type allergic inflammation in asthma by modulating lung DC phenotype and functions, highlighting its therapeutic potential for inflammatory airway conditions and other related immunological disorders.

Contextual AI models for single-cell protein biology

Understanding protein function and developing molecular therapies require deciphering the cell types in which proteins act as well as the interactions between proteins. However, modeling protein interactions across biological contexts remains challenging for existing algorithms. Here, we introduce Pinnacle, a geometric deep learning approach that generates context-aware protein representations. Leveraging a multi-organ single-cell atlas, Pinnacle learns on contextualized protein interaction networks to produce 394,760 protein representations from 156 cell type contexts across 24 tissues. Pinnacle's embedding space reflects cellular and tissue organization, enabling zero-shot retrieval of the tissue hierarchy. Pretrained protein representations can be adapted for downstream tasks: enhancing 3D structure-based representations for resolving immuno-oncological protein interactions, and investigating drugs' effects across cell types. Pinnacle outperforms state-of-the-art models in nominating therapeutic targets for rheumatoid arthritis and inflammatory bowel diseases, and pinpoints cell type contexts with higher predictive capability than context-free models. Pinnacle's ability to adjust its outputs based on the context in which it operates paves way for large-scale context-specific predictions in biology.

Knowledge mapping of links between dendritic cells and allergic diseases: A bibliometric analysis (2004-2023)

In this study, bibliometric analysis was carried out to comprehend the global research trends, hotspots, scientific frontiers, and output characteristics of the links between dendritic cells (DCs) and allergic diseases from 2004 to 2023. Publications and their recorded information were retrieved from the Web of Science Core Collection (WoSCC). VOSviewer and Citespace were used to visualize the hotspots and trends of research area. ChemBio 3D, Autodock tools, and Discovery Studio were used to visualize the molecular docking results of hotspots. A total of 4861 articles were retrieved. The number of publications (Np) was in a high and stable state. Years 2011 and 2017 were two peaks in Np. The largest contributor in terms of publications, scholars, and affiliations was the USA. The paper published in NATURE MEDICINE (IF: 82.9) and written by Trompette, A in 2006 had the highest global citation score (GCS). Keywords, such as "asthma," "t-cells," "inflammation," "expression," "atopic dermatitis," "food allergy," "gut microbiota," "murine model," and "cytokines related to immunity" appeared the most frequently. Most of the binding free energy of the key active components of Saposhnikovia divaricata docked with toll-like receptor proteins well. This bibliometric study aimed to help better comprehend the present state and make decisions from a macro viewpoint.

Decoding Behcet's Uveitis: an In-depth review of pathogenesis and therapeutic advances

Behcet's disease (BD) is a rare but globally distributed vasculitis that primarily affects populations in the Mediterranean and Asian regions. Behcet's uveitis (BU) is a common manifestation of BD, occurring in over two-thirds of the patients. BU is characterized by bilateral, chronic, recurrent, non-granulomatous uveitis in association with complications such as retinal ischemia and atrophy, optic atrophy, macular ischemia, macular edema, and further neovascular complications (vitreous hemorrhage, neovascular glaucoma). Although the etiology and pathogenesis of BU remain unclear, numerous studies reveal that genetic factors (such as HLA-B51), dysregulated immune responses of both the innate and adaptive immune systems, infections (such as streptococcus), and environmental factors (such as GDP) are all involved in its development. Innate immunity, including hyperactivity of neutrophils and γδT cells and elevated NK1/NK2 ratios, has been shown to play an essential role in this disease. Adaptive immune system disturbance, including homeostatic perturbations, Th1, Th17 overaction, and Treg cell dysfunction, is thought to be involved in BU pathogenesis. Treatment of BU requires a tailored approach based on the location, severity of inflammation, and systemic manifestations. The therapy aims to achieve rapid inflammation suppression, preservation of vision, and prevention of recurrence. Systemic corticosteroids combined with other immunosuppressive agents have been widely used to treat BU, and beneficial effects are observed in most patients. Recently, biologics have been shown to be effective in treating refractory BU cases. Novel therapeutic targets for treating BU include the LCK gene, Th17/Treg balance, JAK pathway inhibition, and cytokines such as IL-17 and RORγt. This article summarizes the recent studies on BU, especially in terms of pathogenesis, diagnostic criteria and classification, auxiliary examination, and treatment options. A better understanding of the significance of microbiome composition, genetic basis, and persistent immune mechanisms, as well as advancements in identifying new biomarkers and implementing objective quantitative detection of BU, may greatly contribute to improving the adequate management of BU patients.

STATs signaling pathways in dendritic cells: As potential therapeutic targets?

Dendritic cells (DCs) are professional antigen-presenting cells (APCs), including heterogenous populations with phenotypic and functional diversity that coordinate bridging innate and adaptive immunity. Signal transducer and activator of transcriptions (STAT) factors as key proteins in cytokine signaling were shown to play distinct roles in the maturation and antigen presentation of DCs and play a pivotal role in modulating immune responses mediated by DCs such as differentiation of T cells to T helper (Th) 1, Th2 or regulatory T (Treg) cells. This review sheds light on the importance of STAT transcription factors' signaling pathways in different subtypes of DCs and highlights their targeting potential usages for improving DC-based immunotherapies for patients who suffer from cancer or diverse autoimmune conditions according to the type of the STAT transcription factor and its specific activating or inhibitory agent.

Targeting interleukin-6 as a treatment approach for peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) is a complex manifestation of abdominal cancers, with a poor prognosis and limited treatment options. Recent work identifying high concentrations of the cytokine interleukin-6 (IL-6) and its soluble receptor (sIL-6-Rα) in the peritoneal cavity of patients with PC has highlighted this pathway as an emerging potential therapeutic target. This review article provides a comprehensive overview of the current understanding of the potential role of IL-6 in the development and progression of PC. We discuss mechansims by which the IL-6 pathway may contribute to peritoneal tumor dissemination, mesothelial adhesion and invasion, stromal invasion and proliferation, and immune response modulation. Finally, we review the prospects for targeting the IL-6 pathway in the treatment of PC, focusing on common sites of origin, including ovarian, gastric, pancreatic, colorectal and appendiceal cancer, and mesothelioma.

Tolerogenic CD11c+dendritic cells regulate CD4+Tregs in replacing delayed ischemic preconditioning to alleviate ischemia-reperfusion acute kidney injury

Ischemia-reperfusion injury (IRI) is one of the primary clinical causes of acute kidney injury (AKI). The key to IRI lies in immune-inflammatory damage, where dendritic cells (DCs) play a central role in eliciting immune responses within the context of inflammation induced by ischemia-reperfusion. Our previous study has confirmed that delayed ischemic preconditioning (DIPC) can reduce the kidney injury by mediating DCs to regulate T-cells. However, the clinical feasibility of DIPC is limited, as pre-clamping of the renal artery is not applicable for the prevention and treatment of ischemia-reperfusion acute kidney injury (I/R-AKI) in clinical patients. Therefore, the infusion of DCs as a substitute for DIPC presents a more viable strategy for preventing renal IRI. In this study, we further evaluated the impact and mechanism of infused tolerogenic CD11c+DCs on the kidneys following IRI by isolating bone marrow-derived dendritic cells and establishing an I/R-AKI model after pre-infusion of DCs. Renal function was significantly improved in the I/R-AKI mouse model after pre-infused with CD11c+DCs. The pro-inflammatory response and oxidative damage were reduced, and the levels of T helper 2 (Th2) cells and related anti-inflammatory cytokines were increased, which was associated with the reduction of autologous DCs maturation mediated by CD11c+DCs and the increase of regulatory T-cells (Tregs). Next, knocking out CD11c+DCs, we found that the reduced immune protection of tolerogenic CD11c+DCs reinfusion was related to the absence of own DCs. Together, pre-infusion of tolerogenic CD11c+DCs can replace the regulatory of DIPC on DCs and T-cells to alleviate I/R-AKI. DC vaccine is expected to be a novel avenue to prevent and treat I/R-AKI.

Immune signature and phagocytosis of circulating DC subsets in healthy adults during aging

Dendritic cells (DC) play a pivotal role in the onset and progression of immunosenescence-associated diseases, serving as a link between innate and adaptive immunity. Thus, there is a need to establish reference ranges for DC subset levels in healthy adults and investigate the potential impact of age on DC subset levels and phagocytic activity. Single-platform multi-color flow cytometry was performed to assess the proportions of circulating conventional type 1 DC (cDC1), conventional type 2 DC (cDC2), and plasmacytoid DC (pDC), as well as the percentages of CD80, CD86, CD83, PD-L1, and CD32 in cDC1, cDC2, and pDC. Reference ranges were established based on age and gender, and the percentage of circulating DC subsets in different age groups was compared. In addition, circulating DC were enriched using a magnetic bead sorting kit and co-cultured with polystyrene (PS) beads, categorized by age groups, followed by the evaluation of PS bead phagocytosis using light microscopy and flow cytometry. The results indicated that the percentages of circulating cDC1, cDC2, and CD32+cDC2 decreased with age (P < 0.05) and revealed age-related impairment in phagocytic percentage of cDC2 (P < 0.05). These findings provide a deeper understanding of the impact of age on the phenotype and phagocytic activity of DC subsets, shedding light on their role and function in immunosenescence.

Hydroxychloroquine exacerbates imiquimod-induced psoriasis-like dermatitis through stimulating overexpression of IL-6 in keratinocytes

OBJECTIVE

Hydroxychloroquine (HCQ) is a US Food and Drug Administration (FDA)-approved treatment for systemic lupus erythematosus (SLE) through inhibition of antigen presentation and subsequent reduction in T cell activation. Psoriasis relapse after antimalarial therapy have been reported in up to 18% of patients with psoriasis. Here, we explored the role of HCQ on exacerbating dermatitis utilizing an imiquimod (IMQ)-induced psoriasis-like dermatitis mouse model.

METHODS

Thirty-six C57BL/6 female mice were divided into six groups: wild-type control, IMQ-Only, pre-treat HCQ (30 mg/kg and 60 mg/kg HCQ), and co-treat HCQ with IMQ (30 mg/kg and 60 mg/kg HCQ). Besides control, all were topically treated with IMQ for 5 days. Pharmacological effects and mechanisms of HCQ were assessed by clinical severity of dermatitis, histopathology, and flow cytometry. HaCaT cells were co-treated with both HCQ and recombinant IL-17A, followed by the detection of proinflammatory cytokine expression and gene profiles through enzyme-linked immunosorbent assay and next-generation sequencing.

RESULTS

In the pre-treated and co-treated HCQ groups, skin redness and scaling were significantly increased compared to the IMQ-Only group, and Th17 cell expression was also upregulated. Acanthosis and CD11b+IL23+ dendritic cell (DC) infiltration were observed in the HCQ treatment group. IL-6 overexpression was detected in both the HaCaT cells and skin from the experimental mice. Psoriasis-related genes were regulated after being co-treated with HCQ and recombinant IL-17A in HaCaT cells.

CONCLUSIONS

HCQ exacerbates psoriasis-like skin inflammation by increasing the expression of IL-6, stimulating DC infiltration, and promoting Th17 expression in the microenvironment of the skin.

KEY MESSAGES

This study provided possible mechanisms for inducing psoriasis during HCQ treatment through an animal model.

A mitochondria-targeting dihydroartemisinin derivative as a reactive oxygen species -based immunogenic cell death inducer

Immunogenic cell death (ICD) can activate the anticancer immune response and its occurrence requires high reliance on oxidative stress. Inducing mitochondrial reactive oxygen species (ROS) is a desirable capability for ICD inducers. However, in the category of ICD-associated drugs, numerous reported ICD inducers are a series of anthracyclines and weak in ICD induction. Herein, a mitochondria-targeting dihydroartemisinin derivative (T-D) was synthesized by conjugating triphenylphosphonium (TPP) to dihydroartemisinin (DHA). T-D can selectively accumulate in mitochondria to trigger ROS generation, leading to the loss of mitochondrial membrane potential (ΔΨm) and ER stress. Notably, T-D exhibits far more potent ICD-inducing properties than its parent compound. In vivo, T-D-treated breast cancer cell vaccine inhibits metastasis to the lungs and tumor growth. These results indicate that T-D is an excellent ROS-based ICD inducer with the specific function of trigging vigorous ROS in mitochondria and sets an example for incorporating artemisinin-based drugs into the ICD field.

Mechanistic role of quercetin as inhibitor for adenosine deaminase enzyme in rheumatoid arthritis: systematic review

Rheumatoid arthritis (RA) is an autoimmune disease involving T and B lymphocytes. Autoantibodies contribute to joint deterioration and worsening symptoms. Adenosine deaminase (ADA), an enzyme in purine metabolism, influences adenosine levels and joint inflammation. Inhibiting ADA could impact RA progression. Intracellular ATP breakdown generates adenosine, which increases in hypoxic and inflammatory conditions. Lymphocytes with ADA play a role in RA. Inhibiting lymphocytic ADA activity has an immune-regulatory effect. Synovial fluid levels of ADA are closely associated with the disease's systemic activity, making it a useful parameter for evaluating joint inflammation. Flavonoids, such as quercetin (QUE), are natural substances that can inhibit ADA activity. QUE demonstrates immune-regulatory effects and restores T-cell homeostasis, making it a promising candidate for RA therapy. In this review, we will explore the impact of QUE in suppressing ADA and reducing produced the inflammation in RA, including preclinical investigations and clinical trials.

Dental pulp cells cocultured with macrophages aggravate the inflammatory conditions stimulated by LPS

BACKGROUND

Pulp inflammation is complex interactions between different types of cells and cytokines. To mimic the interactions of different types of cells in inflamed dental pulp tissues, dental pulp cells (DPCs) were cocultured with different ratios of macrophages (THP-1) or LPS treatment.

METHODS

DPCs were cocultured with various ratios of THP-1, then photographed cell morphology and determined cell viability by MTT assay at preset times. Total RNA was also extracted to measure the inflammation marker-IL-6 and IL-8 expressions by RT-Q-PCR. The DPCs and THP-1 were treated with 0.01 - 1μg/ml lipopolysaccharide (LPS) and extract RNA at preset times, and detected IL-6 and IL-8 expression. DPCs were cocultured with various ratios of THP-1 with 0.1 μg/mL LPS, and detected IL-6 and IL-8 expression after 24 and 48 h. The data were analyzed by unpaired t-test or Mann-Whitney test. Differences were considered statistically significant when p < 0.05.

RESULTS

THP-1 and DPCs coculture models did not suppress the viability of DPCs and THP-1. Cocultured with various ratios of THP-1 could increase IL-6 and IL-8 expressions of DPCs (p = 0.0056 - p < 0.0001). The expressions of IL-6 and IL-8 were stronger in higher ratio groups (p = 0.0062 - p < 0.0001). LPS treatment also induced IL-6 and IL-8 expressions of DPCs and THP-1 (p = 0.0179 - p < 0.0001 and p = 0.0189 - p < 0.0001, separately). Under the presence of 0.1 μg/mL LPS, DPCs cocultured with THP-1 for 24 h also enhanced IL-6 and IL-8 expression (p = 0.0022). After cocultured with a higher ratio of THP-1 for 48 h, IL-6 and IL-8 expressions were even stronger in the presence of LPS (p = 0.0260).

CONCLUSIONS

Coculturing dental pulp cells and macrophages under LPS treatment aggravate the inflammatory process. The responses of our models were more severe than traditional inflamed dental models and better represented what happened in the real dental pulp. Utilizing our models to explore the repair and regeneration in endodontics will be future goals.

The bidirectional immune crosstalk in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an unabated risk factor for end-stage liver diseases with no available therapies. Dysregulated immune responses are critical culprits of MASLD pathogenesis. Independent contributions from either the innate or adaptive arms of the immune system or their unidirectional interplay are commonly studied in MASLD. However, the bidirectional communication between innate and adaptive immune systems and its impact on MASLD remain insufficiently understood. Given that both innate and adaptive immune cells are indispensable for the development and progression of inflammation in MASLD, elucidating pathogenic contributions stemming from the bidirectional interplay between these two arms holds potential for development of novel therapeutics for MASLD. Here, we review the immune cell types and bidirectional pathways that influence the pathogenesis of MASLD and highlight potential pharmacologic approaches to combat MASLD based on current knowledge of this bidirectional crosstalk.

A human 3D immune competent full-thickness skin model mimicking dermal dendritic cell activation

We have integrated dermal dendritic cell surrogates originally generated from the cell line THP-1 as central mediators of the immune reaction in a human full-thickness skin model. Accordingly, sensitizer treatment of THP-1-derived CD14-, CD11c+ immature dendritic cells (iDCs) resulted in the phosphorylation of p38 MAPK in the presence of 1-chloro-2,4-dinitrobenzene (DNCB) (2.6-fold) as well as in degradation of the inhibitor protein kappa B alpha (IκBα) upon incubation with NiSO4 (1.6-fold). Furthermore, NiSO4 led to an increase in mRNA levels of IL-6 (2.4-fold), TNF-α (2-fold) and of IL-8 (15-fold). These results were confirmed on the protein level, with even stronger effects on cytokine release in the presence of NiSO4: Cytokine secretion was significantly increased for IL-8 (147-fold), IL-6 (11.8-fold) and IL-1β (28.8-fold). Notably, DNCB treatment revealed an increase for IL-8 (28.6-fold) and IL-1β (5.6-fold). Importantly, NiSO4 treatment of isolated iDCs as well as of iDCs integrated as dermal dendritic cell surrogates into our full-thickness skin model (SM) induced the upregulation of the adhesion molecule clusters of differentiation (CD)54 (iDCs: 1.2-fold; SM: 1.3-fold) and the co-stimulatory molecule and DC maturation marker CD86 (iDCs ~1.4-fold; SM:~1.5-fold) surface marker expression. Noteworthy, the expression of CD54 and CD86 could be suppressed by dexamethasone treatment on isolated iDCs (CD54: 1.3-fold; CD86: 2.1-fold) as well as on the tissue-integrated iDCs (CD54: 1.4-fold; CD86: 1.6-fold). In conclusion, we were able to integrate THP-1-derived iDCs as functional dermal dendritic cell surrogates allowing the qualitative identification of potential sensitizers on the one hand, and drug candidates that potentially suppress sensitization on the other hand in a 3D human skin model corresponding to the 3R principles ("replace", "reduce" and "refine").

Development of potent unmethylated CpG DNA hydrogel by introducing i-motifs into long single-stranded DNA

Unmethylated cytosine-phosphate-guanine (CpG) DNA is recognized by Toll-like receptor 9, expressed in the endosomes of immune cells, and induces the secretion of proinflammatory cytokines. CpG DNA is, therefore, expected to be used as vaccine adjuvants, but there are many obstacles for its therapeutic application, such as poor cellular uptake and biostability. Long single-stranded DNA (lssDNA) synthesized by rolling circle amplification can be a useful delivery carrier for CpG DNA because of its cellular uptake efficiency, but the immunostimulatory effect is transient because it is easily degraded in endosomes. To improve its stability, we constructed lssDNA which forms hydrogel by i-motifs in an acidic environment mimicking endosome, and incorporated CpG DNA into lssDNA (i-CpG-lssDNA). We synthesized lssDNA containing the optimized i-motif sequence, and confirmed the formation of a DNA hydrogel in an acidic environment. The i-CpG-lssDNA elicited a potent proinflammatory cytokine production in murine macrophages, compared to CpG DNA-containing lssDNA without i-motifs. Consistently, its intradermal administration induced potent inflammatory cytokines at the regional lymph nodes. These results suggested that i-CpG-lssDNA could serve as a novel type of adjuvant for the induction of a potent immune response.

Depletion of soluble cytokines unlocks the immunomodulatory bioactivity of extracellular vesicles

Despite an enormous interest in understanding the bioactivity of extracellular vesicles (EV) in physiology and disease for the development of therapeutic applications, the impact of EV preparation methods remains minimally explored. In this study, we implemented density gradient ultracentrifugation combined with size-exclusion chromatography (DG-SEC), differential ultracentrifugation (dUC) and/or stand-alone SEC (sSEC) to fractionate media conditioned by different cancer cells and/or cancer-associated fibroblasts (CAF). EV-enriched but protein-depleted versus EV-depleted but protein-enriched DG-SEC fractions, and EV-containing dUC and sSEC preparations were quality controlled for particle number, protein concentration, selected protein composition and ultrastructure, characterized for their cytokine content, and dose-dependently evaluated for monocyte-derived dendritic cell (MoDC) maturation by measuring surface marker expression and/or cytokine secretion. EV preparations obtained by DG-SEC from media conditioned by different cancer cell lines or CAF, were depleted from soluble immune suppressive cytokines such as VEGF-A and MCP-1 and potently stimulated MoDC maturation. In contrast, EV-containing dUC or sSEC preparations were not depleted from these soluble cytokines and were unable to mature MoDC. Subsequent processing of dUC EV preparations by SEC dose-dependently restored the immunomodulatory bioactivity. Overall, our results demonstrate that method-dependent off-target enrichment of soluble cytokines has implications for the study of EV immunomodulatory bioactivity and warrants careful consideration.

Contrariety of Human Bone Marrow Mesenchymal Stromal Cell Functionality in Modulating Circulatory Myeloid and Plasmacytoid Dendritic Cell Subsets

Mesenchymal Stromal Cells (MSCs) derived from bone marrow are widely tested in clinical trials as a cellular therapy for potential inflammatory disorders. The mechanism of action of MSCs in mediating immune modulation is of wide interest. In the present study, we investigated the effect of human bone-marrow-derived MSCs in modulating the circulating peripheral blood dendritic cell responses through flow cytometry and multiplex secretome technology upon their coculture ex vivo. Our results demonstrated that MSCs do not significantly modulate the responses of plasmacytoid dendritic cells. However, MSCs dose-dependently promote the maturation of myeloid dendritic cells. Mechanistic analysis showed that dendritic cell licensing cues (Lipopolysaccharide and Interferon-gamma) stimulate MSCs to secret an array of dendritic cell maturation-associated secretory factors. We also identified that MSC-mediated upregulation of myeloid dendritic cell maturation is associated with the unique predictive secretome signature. Overall, the present study demonstrated the dichotomy of MSC functionality in modulating myeloid and plasmacytoid dendritic cells. This study provides clues that clinical trials need to investigate if circulating dendritic cell subsets in MSC therapy can serve as potency biomarkers.

Engineering and Development of a Tissue Model for the Evaluation of Microneedle Penetration Ability, Drug Diffusion, Photothermal Activity, and Ultrasound Imaging: A Promising Surrogate to Ex Vivo and In Vivo Tissues

Driven by regulatory authorities and the ever-growing demands from industry, various artificial tissue models have been developed. Nevertheless, there is no model to date that is capable of mimicking the biomechanical properties of the skin whilst exhibiting the hydrophilicity/hydrophobicity properties of the skin layers. As a proof-of-concept study, tissue surrogates based on gel and silicone are fabricated for the evaluation of microneedle penetration, drug diffusion, photothermal activity, and ultrasound bioimaging. The silicone layer aims to imitate the stratum corneum while the gel layer aims to mimic the water-rich viable epidermis and dermis present in in vivo tissues. The diffusion of drugs across the tissue model is assessed, and the results reveal that the proposed tissue model shows similar behavior to a cancerous kidney. In place of typical in vitro aqueous solutions, this model can also be employed for evaluating the photoactivity of photothermal agents since the tissue model shows a similar heating profile to skin of mice when irradiated with near-infrared laser. In addition, the designed tissue model exhibits promising results for biomedical applications in optical coherence tomography and ultrasound imaging. Such a tissue model paves the way to reduce the use of animals testing in research whilst obviating ethical concerns.

Chronic LCMV infection regulates the effector T cell response by inducing the generation of less immunogenic dendritic cells

Chronic viral infection impairs systemic immunity in the host; however, the mechanism underlying the dysfunction of immune cells in chronic viral infection is incompletely understood. In this study, we studied the lineage differentiation of hematopoietic stem cells (HSCs) during chronic viral infection to elucidate the changes in dendritic cell (DC) differentiation and subsequent impact on T cell functionality using a chronic lymphocytic choriomeningitis virus (LCMV) infection model. We first investigated the lineage differentiation of HSCs in the bone marrow (BM) to elucidate the modulation of immune cell differentiation and found that the populations highly restrained in their differentiation were common myeloid progenitors (CMPs) and common dendritic cell progenitors (CDPs). Of interest, the main immune cells infected with LCMV Clone 13 (CL13) in the BM were CD11b/c⁺ myeloid DCs. We next characterized CD11b⁺ DCs that differentiated during chronic LCMV infection. These DCs displayed a less immunogenic phenotype than DCs in naive or acutely infected mice, showing low expression of CD80 but high expression of PD-L1, B7-H4, IDO, TGF-β, and IL-10. Consequently, these CD11b⁺ DCs induced less effective CD8⁺ T cells and more Foxp3⁺ regulatory T (Treg) cells. Furthermore, CD11b⁺ DCs generated during CL13 infection could not induce effective CD8⁺ T cells specific to the antigens of newly invading pathogens. Our findings demonstrate that DCs generated from the BM during chronic viral infection cannot activate fully functional effector CD8⁺ T cells specific to newly incoming antigens as well as persistent antigens themselves, suggesting a potential cause of the functional alterations in the T cell immune response during chronic viral infection.

Adjuvanted quaternized chitosan composite aluminum nanoparticles-based vaccine formulation promotes immune responses in chickens

Aluminum adjuvant is a typical adjuvant that can promote humoral immune response, but it lacks the ability to effectively induce cellular immune response. The water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan nanoparticles (N-2-HACC NPs) can enhance humoral and cellular immune responses of vaccines. To enable aluminum adjuvant to induce cellular immunity, the composite nano adjuvant N-2-HACC-Al NPs were synthesized by the N-2-HACC and aluminum sulfate (Al₂(SO₄)₃). The particle size and zeta potential of the N-2-HACC-Al NPs were 300.70 ± 24.90 nm and 32.28 ± 0.52 mV, respectively. The N-2-HACC-Al NPs have good thermal stability and biodegradability and lower cytotoxicity. In addition, to investigate the immunogenicity of the composite nano adjuvant, the combined inactivated vaccine against Newcastle disease (ND) and H9N2 avian influenza (AI) was prepared with the N-2-HACC-Al NPs as a vaccine adjuvant. The immune effect of the vaccine (N-2-HACC-Al/NDV-AIV) was evaluated by chicken in vivo immunization. The vaccine induced higher levels of serum IgG, IL-4, and IFN-γ than those of the commercial combined inactivated vaccine against ND and H9N2 AI. The levels of IFN-γ were more than twice those of the commercial vaccine at 7 days post the immunization. The N-2-HACC-Al NPs could be used as an efficient nano adjuvant to enhance the effectiveness of vaccine and have immense application potential.

TMPRSS2 Impacts Cytokine Expression in Murine Dendritic Cells

BACKGROUND

The transmembrane protease serine 2 (TMPRSS2) proteolytically activates the envelope proteins of several viruses for viral entry via membrane fusion and is therefore an interesting and promising target for the development of broad-spectrum antivirals. However, the use of a host protein as a target may lead to potential side effects, especially on the immune system. We examined the effect of a genetic deletion of TMPRSS2 on dendritic cells.

METHODS

Bone marrow cells from wild-type (WT) and TMPRSS2-deficient mice (TMPRSS2^-/-) were differentiated to plasmacytoid dendritic cells (pDCs) and classical DCs (cDCs) and activated with various toll-like receptor (TLR) agonists. We analyzed the released cytokines and the mRNA expression of chemokine receptors, TLR7, TLR9, IRF7 and TCF4 stimulation.

RESULTS

In cDCs, the lack of TMPRSS2 led to an increase in IL12 and IFNγ in TLR7/8 agonist resiquimod or TLR 9 agonist ODN 1668-activated cells. Only IL-10 was reduced in TMPRSS2^-/- cells in comparison to WT cells activated with ODN 1668. In resiquimod-activated pDCs, the lack of TMPRSS2 led to a decrease in IL-6, IL-10 and INFγ. ODN 1668 activation led to a reduction in IFNα. The effect on receptor expression in pDCs and cDCs was low.

CONCLUSION

The effect of TMPRSS2 on pDCS and cDCs depends on the activated TLR, and TMPRSS2 seems to affect cytokine release differently in pDCs and cDCs. In cDCs, TMPRSS2 seems to suppress cytokine release, whereas in pDCS TMPRSS2 possibly mediates cytokine release.

A Biomimetic, Silaffin R5-Based Antigen Delivery Platform

Nature offers a wide range of evolutionary optimized materials that combine unique properties with intrinsic biocompatibility and that can be exploited as biomimetic materials. The R5 and RRIL peptides employed here are derived from silaffin proteins that play a crucial role in the biomineralization of marine diatom silica shells and are also able to form silica materials in vitro. Here, we demonstrate the application of biomimetic silica particles as a vaccine delivery and adjuvant platform by linking the precipitating peptides R5 and the RRIL motif to a variety of peptide antigens. The resulting antigen-loaded silica particles combine the advantages of biomaterial-based vaccines with the proven intracellular uptake of silica particles. These particles induce NETosis in human neutrophils as well as IL-6 and TNF-α secretion in murine bone marrow-derived dendritic cells.

An interleukin 6-based genetic risk score strengthened with interleukin 10 polymorphisms associated with long-term kidney allograft outcomes

Of all kidney transplants, half are still lost in the first decade after transplantation. Here, using genetics, we probed whether interleukin 6 (IL-6) could be a target in kidney transplantation to improve graft survival. Additionally, we investigated if a genetic risk score (GRS) based on IL6 and IL10 variants could improve prognostication of graft loss. In a prospective cohort study, DNA of 1271 donor-recipient kidney transplant pairs was analyzed for the presence of IL6, IL6R, IL10, IL10RA, and IL10RB variants. These polymorphisms and their GRS were then associated with 15-year death-censored allograft survival. The C|C-genotype of the IL6 polymorphism in donor kidneys and the combined C|C-genotype in donor-recipient pairs were both associated with a reduced risk of graft loss (p = .043 and p = .042, respectively). Additionally, the GRS based on IL6, IL6R, IL10, IL10RA, and IL10RB variants was independently associated with the risk of graft loss (HR 1.53, 95%-CI [1.32-1.84]; p < .001). Notably, the GRS improved risk stratification and prediction of graft loss beyond the level of contemporary clinical markers. Our findings reveal the merits of a polygenic IL-6-based risk score strengthened with IL-10- polymorphisms for the prognostication and risk stratification of late graft failure in kidney transplantation.

Human Milk Oligosaccharide 2'-Fucosyllactose Modulates Local Viral Immune Defense by Supporting the Regulatory Functions of Intestinal Epithelial and Immune Cells

Human milk contains bioactive components that provide protection against viral infections in early life. In particular, intestinal epithelial cells (IEC) have key regulatory roles in the prevention of enteric viral infections. Here we established an in vitro model to study the modulation of host responses against enteric viruses mimicked by poly I:C (pIC). The effects of 2′-fucosyllactose (2′FL), abundantly present in human milk, were studied on IEC and/or innate immune cells, and the subsequent functional response of the adaptive immune cells. IEC were pre-incubated with 2′FL and stimulated with naked or Lyovec™-complexed pIC (LV-pIC). Additionally, monocyte-derived dendritic cells (moDC) alone or in co-culture with IEC were stimulated with LV-pIC. Then, conditioned-moDC were co-cultured with naïve CD4⁺ T helper (Th)-cells. IEC stimulation with naked or LV-pIC promoted pro-inflammatory IL-8, CCL20, GROα and CXCL10 cytokine secretion. However, only exposure to LV-pIC additionally induced IFNβ, IFNλ1 and CCL5 secretion. Pre-incubation with 2′FL further increased pIC induced CCL20 secretion and LV-pIC induced CXCL10 secretion. LV-pIC-exposed IEC/moDC and moDC cultures showed increased secretion of IL-8, GROα, IFNλ1 and CXCL10, and in the presence of 2′FL galectin-4 and -9 were increased. The LV-pIC-exposed moDC showed a more pronounced secretion of CCL20, CXCL10 and CCL5. The moDC from IEC/moDC cultures did not drive T-cell development in moDC/T-cell cultures, while moDC directly exposed to LV-pIC secreted Th1 driving IL-12p70 and promoted IFNγ secretion by Th-cells. Hereby, a novel intestinal model was established to study mucosal host-defense upon a viral trigger. IEC may support intestinal homeostasis, regulating local viral defense which may be modulated by 2′FL. These results provide insights regarding the protective capacity of human milk components in early life.

Providing a Helping Hand: Metabolic Regulation of T Follicular Helper Cells and Their Association With Disease

T follicular helper (Tfh) cells provide support to B cells upon arrival in the germinal center, and thus are critical for the generation of a robust adaptive immune response. Tfh express specific transcription factors and cellular receptors including Bcl6, CXCR5, PD-1, and ICOS, which are critical for homing and overall function. Generally, the induction of an immune response is tightly regulated. However, deviation during this process can result in harmful autoimmunity or the inability to successfully clear pathogens. Recently, it has been shown that Tfh differentiation, activation, and proliferation may be linked with the cellular metabolic state. In this review we will highlight recent discoveries in Tfh differentiation and explore how these cells contribute to functional immunity in disease, including autoimmune-related disorders, cancer, and of particular emphasis, during infection.