Number Of mDCs Research Articles

Analysis of immunogenic cell death in ascending thoracic aortic aneurysms based on single-cell sequencing data.

At present, research on immunogenic cell death (ICD) is mainly associated with cancer therapy. Little is known about the role of ICD in cardiovascular disease, especially in ascending thoracic aortic aneurysms (ATAA). ATAA single-cell RNA (scRNA) sequencing data were analyzed to identify the involved cell types and determine their transcriptomic characteristics. The chi-square test, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, Gene Set Enrichment Analysis (GSEA), and CellChat for cell-to-cell communication analysis from the Gene Expression Omnibus (GEO) database were used. A total of 10 cell types were identified, namely, monocytes, macrophages, CD4 T/NK (CD4+ T cells and natural killer T cells), mast cells, B/Plasma B cells, fibroblasts, endothelial cells, cytotoxic T cells (CD8+ T cells, CTLs), vascular smooth muscle cells (vSMCs), and mature dendritic cells (mDCs). A large number of inflammation-related pathways were present in the GSEA results. A large number of ICD-related pathways were found in the KEGG enrichment analysis of differentially expressed genes in endothelial cells. The number of mDCs and CTLs in the ATAA group was significantly different from that in the control group. A total of 44 pathway networks were obtained, of which 9 were associated with ICD in endothelial cells (CCL, CXCL, ANNEXIN, CD40, IL1, IL6, TNF, IFN-II, GALECTIN). The most important ligand-receptor pair by which endothelial cells act on CD4 T/NK cells, CTLs and mDCs is CXCL12-CXCR4. The most important ligand-receptor pair by which endothelial cells act on monocytes and macrophages is ANXA1-FPR1. The most important ligand-receptor pair by which CD4 T/NK cells and CTLs act on endothelial cells is CCL5-ACKR1. The most important ligand-receptor pair that myeloid cells (macrophages, monocytes and mDCs) act on endothelial cells is CXCL8-ACKR1. Moreover, vSMCs and fibroblasts mainly promote inflammatory responses through the MIF signaling pathway. ICD is present in ATAA and plays an important role in the development of ATAA. The target cells of ICD may be mainly endothelial cells, in which the aortic endothelial cell ACKR1 receptor can not only promote T-cell infiltration through the CCL5 ligand but also promote myeloid cell infiltration through the CXCL8 ligand. ACKR1 and CXCL12 may become target genes for ATAA drug therapy in the future.

DDC‐OMDC: Deadline‐based data collection using optimal mobile data collectors in Internet of Things

SummaryMobile data collectors (MDCs) are very efficient for data collection in internet of things (IoT) sensor networks. These data collectors collect data at rendezvous points to reduce data collection latency. It is paramount to determine these points in an IoT network to collect data in real time. It is important to consider IoT network characteristics to collect data on a specific deadline. First, the disconnected IoT sensor network is a real challenge in IoT applications. Second, it is essential to determine optimal data collection points (DCPs) and MDCs simultaneously to collect data in real time. In this study, Deadline‐based Data Collection using Optimal Mobile Data Collectors (DDC‐OMDC) scheme is proposed that aims to collect data in a disconnected network with the optimal number of mobile data collectors in a specific deadline for delay‐intolerant applications. DDC‐OMDC works in two phases. In the first phase, the optimal number of MDCs is determined to collect data at the optimal data collection points to guarantee one‐hop data collection from each cluster. The optimal mobile data collectors are determined using optimal DCPs, data collection stopping time, and a specific deadline. In the second phase, the optimal data collection trajectory is determined for each MDC using the nearest neighbor heuristic algorithm to collect data in real time. The simulation results show that the proposed scheme outperforms in collecting data in real time and determines optimal mobile data collectors and optimal data collection trajectory to collect data in a specific deadline for delay‐intolerant applications.

Myeloid dendritic cells are increased in the lesional skin and associated with pruritus in patients with prurigo nodularis.

The number of dermal mDCs (CD11c+ cells) was increased with itch intensity (r=0.886, p=0.003) using immunofluorescence (IF). On IF, CD11c+ mDCs expressed IL-31 in lesional PN skin. Fluorescence in situ hybridization combined with IF also confirmed IL-31 mRNA expression by mDCs in PN lesion. Higher population of colocalization of CD11c+ mDCs expressing IL-31 mRNA were more than CD68+ macrophages and CD3+ T cells in consecutive sections of PN skin lesion. HC, healthy control; PN, prurigo nodularis; SPN, PN with severe pruritus (itch NRS score ≥7 points); MPN, PN with mild pruritus (itch NRS score <3 points); NRS, Numeric Rating Scale; AD, atopic dermatitis; mDC, myeloid dendritic cell.

Plasminogen and plasmin can bind to human T cells and generate truncated CCL21 that increases dendritic cell chemotactic responses

Plasmin is a broad-spectrum protease and therefore needs to be tightly regulated. Active plasmin is formed from plasminogen, which is found in high concentrations in the blood and is converted by the plasminogen activators. In the circulation, high levels of α2-antiplasmin rapidly and efficiently inhibit plasmin activity. Certain myeloid immune cells have been shown to bind plasmin and plasminogen on their cell surface via proteins that bind to the plasmin(ogen) kringle domains. Our earlier work showed that T cells can activate plasmin but that they do not themselves express plasminogen. Here, we demonstrate that T cells express several known plasminogen receptors and that they bind plasminogen on their cell surface. We show T cell–bound plasminogen was converted to plasmin by plasminogen activators upon T cell activation. To examine functional consequences of plasmin generation by activated T cells, we investigated its effect on the chemokine, C-C motif chemokine ligand 21 (CCL21). Video microscopy and Western blotting confirmed that plasmin bound by human T cells cleaves CCL21 and increases the chemotactic response of monocyte-derived dendritic cells toward higher CCL21 concentrations along the concentration gradient by increasing their directional migration and track straightness. These results demonstrate how migrating T cells and potentially other activated immune cells may co-opt a powerful proteolytic system from the plasma toward immune processes in the peripheral tissues, where α2-antiplasmin is more likely to be absent. We propose that plasminogen bound to migrating immune cells may strongly modulate chemokine responses in peripheral tissues.

Effect of BCG HSP70 Gene Transfection on Dendritic Cells Derived From Bone Marrow in Children With Acute Leukemia.

In this study, immature dendritic cells (imDCs) were transfected with the Bacillé Calmette-Guérin (BCG) heat shock protein 70 (HSP70) gene to investigate the impact on the maturity and function of imDCs from the bone marrow of pediatric patients with acute leukemia. Bone marrow mononuclear cells were isolated from pediatric patients with acute lymphoblastic leukemia who had achieved complete remission at least 6 months prior. The recombinant vector pDisplay-HSP70 was transfected into imDCs. The test groups included 5 subgroups: imDCs (imDCs without special processing), imDC-neos (imDCs transfected with the pDisplay vector), HSP70 (imDCs transfected with the pDisplay-HSP70 vector), tumor necrosis factor α (TNF-α) (imDCs induced with rhTNF-α), and HSP70+TNF-α. Mature dendritic cells (mDCs) from different groups (HSP70, TNF-α, and HSP70+TNF-α) and T cells were cultured. An equal number of lymphocytes and mDCs were used as controls. The proliferation indices of T cells and the cytokine contents (interleukin-12 and interferon-γ) were determined. The HSP70 group and the TNF-α group expressed higher levels of HLA-DR, CD80, and CD86 but lower levels than the HSP70+TNF-α group; there was no significant difference between the HSP70 group and the TNF-α group. The combination of HSP70 and TNF-α induced the highest levels of interleukin-12 and interferon-γ. The outcomes of this study indicated that gene transfection with BCG HSP70 evidently promoted imDC maturity and the antitumor effects of mDC-mediated T cells. It could serve as a candidate gene-modified cell vaccine for tumor immunotherapy.

Pyruvate Kinase M2 Regulates Hif-1alpha Activity in Myeloid Dendritic Cells from Patients with Severe Aplastic Anemia

Hypoxia-inducible factor 1 (HIF-1) is a nuclear protein with transcriptional activity. HIF-1 can be activated by immune cells exposed to hypoxia and regulate glycolysis. In this regulation, pyruvate kinase M2 (PKM2), a key enzyme in the cell glycolytic pathway, is an important regulatory site. Our previous studies suggest that PKM expression is increased in myeloid dendritic cells (mDCs) in SAA patients. Therefore, we investigated the expression level of HIF-1α in mDCs and its interaction with PKM2 in SAA patients. 1.The HIF-1α expression of mRNA and protein on mDCs in SAA untreated patients was significantly higher than that in SAA remission patients and normal controls.2.In the SAA patients, the HIF-1α expression on mDCs was positively correlated with the numbers of mDCs (p < 0.01), CD80+mDC/mDC (r = 0.689, p < 0.01), and CD86+mDC/mDC in PB (p < 0.05).3.In SAA patients, the HIF-1α expression on mDCs was negatively correlated with the CD4+T/CD8+T ratio in peripheral blood (PB) (p < 0.05), the percentage of granulocytoid and erythroid cells in bone marrow (p < 0.05), the WBC count in PB (p < 0.05), ANC in PB (p < 0.05), and the percentage of Rets in the PB (p < 0.05); was positively correlated with the percentage of lymphoid cells in bone marrow(p < 0.05); and was not statistically correlated with the megakaryocyte number in bone marrow, absolute PBL count, HGB in PB, absolute Ret count in PB, or PLT count in PB.4.In the correlation analysis we observed that there was a positively correlation between HIF-1α and PKM2 expression on mDCs in SAA patients (p < 0.001). To evaluate whether there is a mutual adjustment relationship between HIF-1α and PKM2, we successfully reduced PKM2 gene expression in this cell population via siRNA transfection. This process resulted in significantly lower levels of PKM2 protein expression relative to cells transfected with siControl which were evaluated by western blotting. We observed that the relative expression levels of HIF-1α mRNA in mDCs transfected with PKM2 siRNA was lower than siControl group（P< 0.01）.Conclusions 1.In this study, we found that untreated patients with SAA had higher HIF-1α expression on mDCs compared with recovering SAA patients and normal controls. The expression of HIF-1α was correlated with the number and function in mDCs and the severity of pancytopenia of SAA.2.The results indicated that the mRNA expression level of HIF-1α in mDC of SAA patients at the onset was significantly higher than that of the remission group and the control group, and was significantly positively correlated with the expression of PKM2.3.The mRNA expression level of HIF-1α in mDC of SAA patients at the onset was significantly higher than that of the remission group and the control group, and was significantly positively correlated with the expression of PKM2. The above experimental results confirmed that HIF-1α plays an important role in the abnormal immune response in patients with severe aplastic anemia, mainly by regulating the activity of PKM2 and thereby affecting the energy metabolism in immune cells. DisclosuresNo relevant conflicts of interest to declare.

AB018. Myeloid dendritic cells (mDCs) are major producers of interferon-beta in dermatomyositis and increased numbers of mDCs are found in hydroxychloroquine nonresponders

BackgroundDermatomyositis (DM) is an autoimmune disease affecting skin, skeletal muscle, and lungs. Pathogenesis is considered largely driven by interferon-beta (IFN-beta) and involves CD4+ cells and dendritic cells (DCs). (I) Quantify inflammatory cells and IFN-beta in skin; correlate with Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) scores. (II) Identify DC type contributing to refractoriness to hydroxychloroquine (HCQ). (III) Compare IFN-beta production by mDCs vs. pDCs in DM.Methods(I) DM skin biopsies evaluated for cells and cytokines using IHC from 12 patients with moderate-severe skin disease at baseline and after 12 weeks of therapy. (II) IHC performed on skin biopsies to compare myeloid DC (mDC) and pDC expression in HCQ-responders vs. -nonresponders. (III) Flow cytometry performed on PBMCs from 5 healthy controls and 5 DM patients.Results(I) CD4+ cells, macrophages, mDCs, and TRM cells were the most populous in DM skin, followed by CD8+ cells, mast cells, and pDCs. Change in CD4+ and CD8+ cells/HPF significantly correlated with change in CDASI scores (r=0.82, P<0.05; r=0.81, P<0.05). Changes in IFN-beta protein expression correlated with change in CDASI scores (r=0.63, P<0.05). (II) Significantly increased mDCs/HPF found in skin of HCQ nonresponders (P<0.05). (III) mDCs and pDCs both produced IFN-beta in DM patients; pDCs were dominant producers of IFN-beta in healthy controls.ConclusionsmDCs are major producers of IFN-beta in DM patients and may play an important role in DM pathogenesis.

Features of the subpopulation composition of dendritic cells in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common rheumatic diseases. Dendritic cells (DCs) as the main antigen-presenting cells play an important role in the pathogenesis of RA. There are two major DC populations: myeloid and plasmacytoid DCs (mDCs and pDCs). B cells as antibody-producing cells also play an important role in the pathogenesis of RA. The probability of achieving low disease activity and clinical and laboratory remission has been proven to be maximal in the very early period of the disease and in the patients who have not been previously prescribed disease-modifying antirheumatic drugs (DMARDs). In this connection, it is necessary to elaborate additional criteria and biomarkers for early RA. Objective : to investigate the subpopulation composition of DCs in patients with early-stage RA. Patients and methods . The investigation enrolled 60patients with RA who met the 2010 ACR/EULAR and the 1987ACR criteria. The patients with RA were divided into two groups: 1) 30patients with early RA (the disease duration was not more than 1 year); 2) 30 patients with advanced RA. A control group consisted of 30 patients with osteoarthritis (OA) who met the ACR criteria. All the patients with RA were treated with DMARDs. The patients with early RA had not previously received DMARDs; after being included in the study, they were prescribed methotrexate 15-20 mg/week. The patients with advanced RA took methotrexate 15-25 mg/week (n=24), sulfasalazine 2 g/day (n=5), or leflunomide 20 mg/day (n=1). At the first stage, the levels of different subpopulations of DCs and B lymphocytes were studied in the patients with early RA before initiation of therapy and in those with advanced RA and in the control persons. At the following stage, the time course of changes was investigated in the subpopulation composition of DCs and B lymphocytes during therapy. Results and discussion . The subpopulations of peripheral blood DCs in early RA were characterized. A subpopulation of mDCs was shown to dominate in the patients with early RA versus those with advanced RA or osteoarthritis (OA). In addition, the patients with RA showed a high B lymphocyte level. It was noted that there was no significant differences in the level of pDCs between RA and OA patients and there was an inverse relationship between the relative peripheral blood level of pDC and disease activity, which confirms the immunosuppressive role of pDCs in the pathogenesis of RA. The levels of mDCs and B lymphocytes during DMARD therapy were ascertained to significantly decrease to those seen in healthy donors. Conclusion . Thus, the findings suggest that the number of mDCs and B lymphocytes increases in patients with early RA, unlike those with OA. In addition, the change in the number of mDCs and B cells during therapy is associated with the dynamics of disease activity and may suppose that mDCs are a target for the action of DMARDs.

Abstract 65: Impact of tumor-infiltrating dendritic cells in esophageal squamous cell carcinoma treated with neoadjuvant chemotherapy

Abstract Background: Tumor-infiltrating CD8+T cells have been found to be associated with favorable outcome of patients in many cancers including esophageal squamous cell carcinoma (ESCC). Dendritic cells (DCs) are the most potent antigen-presenting cells to induce CD8+T cells. Several investigators have shown that tumor infiltrating mature DCs (mDCs) were associated with favorable prognosis of cancer patients. We showed that mDCs were associated with favorable prognosis of ESCC patients who had not received preoperative treatment. Neoadjuvant chemotherapy (NAC) is the standard treatment for Stage II/ III thoracic esophageal carcinoma in Japan. The effect of chemotherapy on tumor infiltrating DCs remains unclear. Purpose: The aim of this study was to examine the correlation of efficacy of NAC and locally infiltrating DCs in ESCC patients. Object and Methods: Formalin-fixed, paraffin-embedded blocks of primary lesions were collected from 50 patients with ESCC who underwent surgical treatment after NAC at Osaka City University Hospital. Immunohistochemical analysis using anti-LAMP-3 antibody and CD8 antibody was used to evaluate tumor infiltrating DCs and CD8+T cells. The number of LAMP-3+DCs and CD8+T cells were counted at ×400 magnification. We divided the 50 cases into two groups according to the median number of tumor infiltrating DCs and CD8+T cells to examine the correlation of efficacy of NAC and locally infiltrating DCs. Results: LAMP-3+DCs were predominantly observed in peritumoral area and sparsely found in intratumoral area, whereas CD8+T cells distributed between both peritumoral and intratumoral areas. LAMP-3+DCs infiltrated the peritumoral space from 0 to 19.0 (median 6.0) and the intratumoral space from 0 to 3.8 (median 0.0). Patients with histological effect (≧Grade 1a) had higher infiltration of mDCs than Grade 0. Patients with high infiltration of mDCs had better prognosis than those with low. The number of mDCs had positive correlation with the number of tumor infiltrating CD8+T cells. Conclusions: Our results suggested that increase of tumor infiltrating mDCs was associated with histological effect of NAC and favorable prognosis in ESCC. Citation Format: Junya Nishimura, Hiroaki Tanaka, Yoshihito Yamakoshi, Soichiro Hiramatsu, Tatsuro Tamura, Takahiro Toyokawa, Kazuya Muguruma, Kosei Hirakawa, Masaichi Ohira. Impact of tumor-infiltrating dendritic cells in esophageal squamous cell carcinoma treated with neoadjuvant chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 65.

Distribution of peripheral dendritic cells in patients with HBV infection or spleen and kidney deficiency

Spleen and kidney deficiency syndrome (SKD), a Traditional Chinese Medicine (TCM) syndrome, is the fundamental mechanisms of TCM. We aim to investigate the distribution of peripheral dendritic cells (DCs) in HBV patients with SKD or non-SKD. Peripheral venous blood from patients with HBV infection and healthy volunteers was collected to extract PBMC, and flow cytometry assay was used to measure the distribution of DCs subsets, including myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs). For the number of pDCs, it was higher in control group and non-SKD group, compared with HBV infection group and SKD group, respectively. For the number of mDCs, it was higher in control group and the non-SKD group compared to SKD group, while in control group it was higher than both HBeAg positive group and negative group. The number of pDCs in control group and chronic hepatitis B group were higher than HBVcarrier group, and it was higher in control group than both immune tolerance group and inactive group, while in immune clearance group it was higher than immune tolerance group and inactve group. The number of mDCs in control group and immune clearance group were higher than that of immune tolerance group. There was an obvious correlation between TCM syndromes and immune function in HBV infected patients, the number of pDCs and mDCs of the SKD group was lower than that in non-SKD group. These results provide a new insight into scientific evidence that TCM probably be based.

Frequency of Dendritic Cells and Their Expression of Costimulatory Molecules in Children with Autism Spectrum Disorders.

The aim of our study was to evaluate the frequencies of myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) in children with ASD. Subjects were 32 children with ASD and 30 healthy children as controls. The numbers of mDCs and pDCs and the expression of CD86 and CD80 on the entire DCs were detected by flow cytometry. ASD children had significantly higher percentages of mDCs and pDCs when compared to controls. We found significant inverse relationships between serum 25-hydroxyvitamin D levels and the frequencies of mDCs and pDCs in autistic children. Our data suggested that DCs could play a role in the clinical course of ASD. The relationship of DCs to immune disorders in ASD remains to be determined.

Blood Myeloid Dendritic Cells and slanDC in Antiretroviral Therapy- Suppressed HIV-Infected Patients.

Myeloid dendritic cells (mDCs) play a complex role in HIV infection regardless of viral replication. The aim of our study was to analyse mDCs in long term antiretroviral therapy (ART)- suppressed HIV-infected patients. We evaluated the numbers of mDCs and slanDC in the context of different degree of CD4+ T cell recovery, persistent T cell activation (as HLA-DR+/CD3+ expression) and monocyte-macrophage activation assessed in terms of circulating levels of both sCD14 and sCD163. We enrolled 72 aviremic patients under effective ART and 34 healthy donors (HD). Patients were divided into two groups on the bases of ΔCD4, indicating the difference between the value of CD4 at the time of sampling and CD4 nadir. Higher levels of mDCs and slanDC were found in patients with ΔCD4>200/mmc in comparison to HD. In those patients also an increased level of sCD14 was found, whereas sCD163 seemed to be at normal levels. An augmentation of activated CD4 T lymphocytes was found, although less pronounced in patients with ΔCD4<200/mmc. In conclusion, our findings showed an expansion of mDCs with a shift to inflammatory slanDC that could sustain both microbial translocation and HIV latency in CD4 T cells.

Dysfunctions in the Mature Dendritic Cells Are Associated with the Presence of Metastases of Colorectal Cancer in the Surrounding Lymph Nodes.

Dendritic cells play a key role in the antigen presentation and T cell activation. The aim of this study was a detailed analysis of the presence of mature dendritic cells (CD 83 positive) in colorectal cancer in correlation with selected clinicopathological parameters. The presence of mature dendritic cells (mDCs) was determined immunohistochemically using the anti-CD83 antibody. The morphometric analysis of the mDCs was performed in the normal colon wall adjacent to the cancerous tumor as well as in the front of the tumor and in the main mass of the cancerous tumor. Decrease in mDCs in the front and in the main tumor mass was observed. The increase in the number of mDCs in both of these locations was associated with the presence of metastases in the nearby lymph nodes (p < 0.05 and p < 0.01). Furthermore, the increase in the proportion of mDCs in the main tumor mass was associated with the presence of the invasion of tumor cells into the blood and lymph vessels (p < 0.01). The increase in the amount of mDCs in the cancerous tumor is associated with the invasiveness of the tumor and especially with the metastasis to the surrounding lymph nodes.

Safe and Reproducible Preparation of Functional Dendritic Cells for Immunotherapy in Glioblastoma Patients.

Cell therapy based on dendritic cells (DCs) pulsed with tumor lysate is a promising approach in addition to conventional therapy for the treatment of patients with glioblastoma (GB). The success of this approach strongly depends on the ability to generate high-quality, functionally mature DCs (mDCs), with a high level of standardization and in compliance with Good Manufacturing Practices. In the cell factory of the Carlo Besta Foundation, two phase I clinical trials on immunotherapy with tumor lysate-loaded DCs as treatment for GB are ongoing. From 2010 to 2014, 54 patients were enrolled in the studies and 54 batches of DCs were prepared. We retrospectively analyzed the results of the quality control tests carried out on each produced batch, evaluating yield of mDCs and their quality in terms of microbiological safety and immunological efficacy. The number of mDCs obtained allowed the treatment of all the enrolled patients. All 54 batches were sterile, conformed to acceptable endotoxin levels, and were free of Mycoplasma species and adventitious viruses. During culture, cells maintained a high percentage of viability (87%-98%), and all batches showed high viability after thawing (mean±SD: 94.6%±2.9%). Phenotype evaluation of mDCs showed an evident upregulation of markers typical of DC maturation; mixed lymphocyte reaction tests for the functional evaluation of DCs demonstrated that all batches were able to induce lymphocyte responses. These results demonstrated that our protocol for DC preparation is highly reproducible and permits generation of large numbers of safe and functional DCs for in vivo use in immunotherapy approaches. Cell therapy based on antigen-pulsed dendritic cells (DCs) is a promising approach for the treatment of glioblastoma patients. The success of this approach strongly depends on the ability to generate high-quality, functional DCs with a high level of standardization, ensuring reproducibility, efficacy, and safety of the final product. This article summarizes the results of the quality controls on 54 batches, to demonstrate the feasibility of producing a therapeutic cell-based vaccine via a well-controlled Good Manufacturing Practices (GMP)-compliant production process. The findings may be of scientific interest to those working in the field of preparation of GMP-compliant products for cell-therapy applications.

Accumulation of FLT3(+) CD11c (+) dendritic cells in psoriatic lesions and the anti-psoriatic effect of a selective FLT3 inhibitor.

Psoriasis is a common chronic T-cell-mediated autoimmune skin disease, and traditional immunotherapies for psoriasis have focused on the direct inhibition of T cells, which often causes toxicity and lacks long-term effectiveness. Safe and effective therapeutic strategies are strongly needed for psoriasis. In this study, we show for the first time a significant accumulation of FLT3(+) CD11c(+) dendritic cells (DCs) in human psoriatic lesions and in the skin of experimental preclinical K14-VEGF transgenic homozygous mice, our animal model, although not an exact match for human psoriasis, displays many characteristics of inflammatory skin inflammation. SKLB4771, a potent and selective FLT3 inhibitor that we designed and synthesised, was used to treat cutaneous inflammation and psoriasis-like symptoms of disease in mice and almost completely cured the psoriasis-like disease without obvious toxicity. Mechanistic studies indicated that SKLB4771 treatment significantly decreased the number and activation of pDCs and mDCs in vitro and in vivo, and subsequent T-cell cascade reactions mediated by Th1/Th17 pathways. These findings show that targeted inhibition of FLT3, and hence direct interference with DCs, may be a novel therapeutic approach for the treatment of psoriasis.

Decreased dendritic cell numbers but increased TLR9-mediated interferon-alpha production in first degree relatives of type 1 diabetes patients

Dendritic cells (DCs) play an important role in pathogenesis of autoimmunity, including type 1 diabetes (T1D). In this study, we investigated DC subpopulations and their responses to TLR stimulation in T1D patients and their relatives. We analyzed the frequency of myeloid (mDCs) and plasmacytoid DCs (pDCs) in 97 T1D patients (69 onset, 28 long-term), 67 first-degree relatives, and 64 controls. We additionally tested the IFN-alpha production by pDCs upon stimulation with TLR 7, 8 and 9 agonists. A lower number of mDCs and pDCs were found in T1D patients and their relatives. Of all the tested TLR ligands, only stimulation with CpG 2216 induced IFN-alpha production that was the highest in T1D relatives, except of autoantibody-negative relatives bearing the protective haplotypes. Our data demonstrate disturbances in DC number and function expressed most significantly in T1D relatives and point to a potential role of TLR9-induced IFN-alpha production in T1D development.

The Aryl Hydrocarbon Receptor Antagonist StemRegenin 1 Promotes Human Plasmacytoid and Myeloid Dendritic Cell Development from CD34+ Hematopoietic Progenitor Cells

The superiority of dendritic cells (DCs) as antigen-presenting cells has been exploited in numerous clinical trials, where generally monocyte-derived DCs (Mo-DCs) are injected to induce immunity in patients with cancer or infectious diseases. Despite promising expansion of antigen-specific T cells, the clinical responses following vaccination have been limited, indicating that further improvements of DC vaccine potency are necessary. Pre-clinical studies suggest that vaccination with combination of primary DC subsets, such as myeloid and plasmacytoid blood DCs (mDCs and pDCs, respectively), may result in stronger clinical responses. However, it is a challenge to obtain high enough numbers of primary DCs for immunotherapy, since their frequency in blood is very low. We therefore explored the possibility to generate them from hematopoietic progenitor cells (HPCs). Here, we show that by inhibiting the aryl hydrocarbon receptor with its antagonist StemRegenin 1 (SR1), clinical-scale numbers of functional BDCA2(+)BDCA4(+) pDCs, BDCA1(+) mDCs, and BDCA3(+)DNGR1(+) mDCs can be efficiently generated from human CD34(+) HPCs. The ex vivo-generated DCs were phenotypically and functionally comparable to peripheral blood DCs. They secreted high levels of pro-inflammatory cytokines such as interferon (IFN)-α, interleukin (IL)-12, and tumor necrosis factor (TNF)-α and upregulated co-stimulatory molecules and maturation markers following stimulation with Toll-like receptor (TLR) ligands. Further, they induced potent allogeneic T-cell responses and activated antigen-experienced T cells. These findings demonstrate that SR1 can be exploited to generate high numbers of functional pDCs and mDCs from CD34(+) HPCs, providing an alternative option to Mo-DCs for immunotherapy of patients with cancer or infections.

OP0222 TSLP expression is increased in RA joints and causes increased activation of intra-articular myeloid dendritic cells with enhanced stimulation of TH1 and TH17 activity

BackgroundThymic stromal lymphopoietin (TSLP) is well known for its potent activation of myeloid dendritic cells (mDCs) resulting in Th2-mediated immune responses. TSLP signals cells via the IL-7 receptor-alpha chain (IL-7Rα),...

SAT0046 Intra-articular CD1C-expressing myeloid dendritic cells from RA patients express increased levels of T cell-attracting chemokines and induce TH1, TH2, and TH17 cell activity

BackgroundMyeloid dendritic cells (mDCs) are potent T cell-activating antigen-presenting cells that have been implicated to play a crucial role in the regulation of tolerance and pro-inflammatory immune responses in many...

SDF-1/CXCL12 recruits B cells and antigen-presenting cells to the thymus of autoimmune myasthenia gravis patients

Myasthenia gravis (MG), a neuromuscular disease mediated by autoantibodies against the anti-acetylcholine receptor, is often associated with thymic hyperplasia characterized by ectopic germinal centers that contain autoreactive T and B cells. The MG thymus is the site of active neoangiogenic processes including the abnormal development of high endothelial venules (HEVs). This study tested the hypothesis that thymic HEVs and associated chemokines participate in MG pathology by mediating peripheral cell recruitment to the MG thymus.We observed that the number of HEVs positively correlated with the degree of thymic hyperplasia. Testing various chemokines, we demonstrated that thymic HEVs selectively expressed SDF-1 mRNA and presented SDF-1 protein on the lumen side. Antigen presenting cells (APCs) such as monocytes/macrophages, dendritic cells (DCs) and B cells expressing SDF-1 receptor CXCR4 were detected inside and around thymic HEVs. In the periphery, CXCR4 expression was especially reduced on myeloid DCs (mDCs). In parallel, the number of mDCs was decreased suggesting a recruitment of these cells from the periphery to MG thymus. Corticosteroid treatment normalized the number of HEVs and may thus decrease the recruitment of peripheral cells. Indeed, it restored the level of CXCR4 on peripheral mDCs and the number of peripheral mDCs.Altogether, our results suggest that HEV development and engagement of SDF-1 contribute to MG pathology by recruitment of peripheral B cells and APCs to the MG thymus.