Function Of Bone Marrow-derived Dendritic Cells Research Articles

Allergen-induced CD11c + dendritic cell pyroptosis aggravates allergic rhinitis

BackgroundPyroptosis is crucial for controlling various immune cells. However, the role of allergen-induced CD11c + dendritic cell (DC) pyroptosis in allergic rhinitis (AR) remains unclear.MethodsMice were grouped into the control group, AR group and necrosulfonamide-treated AR group (AR + NSA group). The allergic symptom scores, OVA-sIgE titres, serum IL-1β/IL-18 levels, histopathological characteristics and T-helper cell-related cytokines were evaluated. CD11c/GSDMD-N-positive cells were examined by immunofluorescence analysis. Murine CD11c + bone marrow-derived DCs (BMDCs) were induced in vitro, stimulated with OVA/HDM, treated with necrosulfonamide (NSA), and further cocultured with lymphocytes to assess BMDC function. An adoptive transfer murine model was used to study the role of BMDC pyroptosis in allergic rhinitis.ResultsInhibiting GSDMD-N-mediated pyroptosis markedly protected against Th1/Th2/Th17 imbalance and alleviated inflammatory responses in the AR model. GSDMD-N was mainly coexpressed with CD11c (a DC marker) in AR mice. In vitro, OVA/HDM stimulation increased pyroptotic morphological abnormalities and increased the expression of pyroptosis-related proteins in a dose-dependent manner; moreover, inhibiting pyroptosis significantly decreased pyroptotic morphology and NLRP3, C-Caspase1 and GSDMD-N expression. In addition, OVA-induced BMDC pyroptosis affected CD4 + T-cell differentiation and related cytokine levels, leading to Th1/Th2/Th17 cell imbalance. However, the Th1/Th2/Th17 cell immune imbalance was significantly reversed by NSA. Adoptive transfer of OVA-loaded BMDCs promoted allergic inflammation, while the administration of NSA to OVA-loaded BMDCs significantly reduced AR inflammation.ConclusionAllergen-induced dendritic cell pyroptosis promotes the development of allergic rhinitis through GSDMD-N-mediated pyroptosis, which provides a clue to allergic disease interventions.AVnLpCxbGNVGDf4VdBhsuLVideo

Multi-signaling pathway activation by pH responsive manganese particles for enhanced vaccination

As metal ions play important roles in the process of immunomodulation, immunotherapy based on metal ions has attracted tremendous interests in recent years. Here, we screened common metal ions and found that Mn2+ could enhance the immune function in vitro. A new type of nanovaccine is thus fabricated by a biomimetic approach using nanoscale coordination polymer formed by Mn2+ and 2-methylimidazole (2-MI) to encapsulate ovalbumin (OVA) protein, a model antigen, obtaining OVA@MM nanoparticles. Compared to free OVA, OVA@MM nanoparticles could more effectively induce the maturation of bone marrow-derived dendritic cells (BMDCs) and their subsequent antigen cross-presentation. The particles made of Mn2+ and 2-MI could activate immune-regulated signal pathways to enhance the immune functions of BMDCs. Such OVA@MM nanovaccine could not only provide prophylactic effect to inhibit the growth of B16-OVA tumor on immunized mice, but also significantly inhibit tumor growth in the mice with B16-OVA tumor combined with anti-programmed cell death protein 1 (anti-PD-1) antibody. Therefore, this nanovaccine platform based on Mn2+, 2-MI and antigen may provide a simple, effective and broadly applicable strategy to enhance adaptive immunity against cancer and other diseases.

Nicotine- and tar-removed cigarette smoke extract modulates the antigen presentation function of mouse bone marrow-derived dendritic cells.

Dendritic cells (DCs) take up antigens derived from pathogens such as bacteria and viruses, and from tumor cells and induce the activation of antigen-specific T cells through major histocompatibility complex (MHC)-mediated antigen presentation. Mainstream cigarette smoke extract (CSE) has various effects, and the effects of its major components, nicotine and tar, have been extensively analyzed. Recently, the physiological effects of nicotine- and tar-removed CSE (cCSE) have also been reported. However, the effects of cCSE on DC-mediated immune responses remain unknown. In this study, we found that cCSE enhanced lipopolysaccharide (LPS)-stimulated induction of the expression of MHC-I and MHC-II on the cell surface of mouse bone marrow-derived DCs (BMDCs). In contrast, cCSE suppressed the induction of CD86 induced by stimulation with curdlan and interferon-gamma (IFN-γ). In addition, cCSE suppressed the production of IL-12, IL-23, and IL-10 by LPS and curdlan stimulation. In the presence of cCSE, LPS-stimulated BMDCs showed enhanced activation of CD4 and CD8 T cells and increased IL-2 production from T cells by antigen presentation in a mixed-leukocyte reaction assay. In contrast, cCSE did not affect the activation of T cells by curdlan- or IFN-γ-stimulated BMDCs, and curdlan-stimulated BMDCs suppressed IL-17 production from T cells and enhanced IFN-γ production. These results suggest that cCSE has different effects on the activation signals induced by LPS, curdlan, and IFN-γ in BMDCs and modulates the antigen presentation function of BMDCs. This article is protected by copyright. All rights reserved.

RNA-Seq approach to investigate the effects of melatonin on bone marrow-derived dendritic cells from dextran sodium sulfate-induced colitis mice

Melatonin (MLT) was reported to have therapeutic effects on inflammatory bowel disease (IBD) such as ulcerative colitis (UC) and Crohn's disease (CD) due to its anti-inflammatory and immunomodulatory properties. However, whether the beneficial effects of melatonin on colitis are through altering the immune response of bone marrow-derived dendritic cells (BMDCs) has not been well characterized. Here, we propose that MLT alleviates dextran sulfate sodium (DSS)-induced colitis in mice through its regulation of the immune response of BMDCs, in which some lncRNA, circRNA, miRNA, and mRNA may be involved. We at first established a DSS-induced colitis mouse model and found that the concentration of MLT in the serum of DSS-induced colitis mice was significantly lower than that in the control mice. Supplementation with MLT alleviated DSS-induced colitis in mice, which was reflected by preventing mouse body weight loss, colon length shortening, inflammation, and epithelial tissue destruction and abscission in the colon. We then isolated and cultured BMDCs and found that MLT could inhibit the activation of BMDCs from the colitis mice, which was reflected by reducing the phagocytotic ability of the cells, inhibiting their migration, and decreasing their secretion of pro-inflammatory cytokines. RNA sequencing results showed that MLT promoted the transformation of BMDCs into immune tolerant phenotypes in DSS-induced colitis mice through affecting non-coding RNAs (ncRNAs). Among them, lncRNA ENSMUST00000226323, circRNA-0520, and circRNA-2243 were predicted to interact with miRNA-709, and mRNAs of Ywhaz and Ccl9 were the targets of miRNA-709, all of which were involved in MLT-induced alteration of BMDCs functions in DSS-induced colitis mice via PI3K-Akt pathway. Our findings may provide some clues for understanding MLT inhibiting inflammatory response in DSS-induced colitis, which may be through alteration of BMDCs function.

Composition and immunomodulatory activity of neutral and acidic polysaccharides isolated from Epimedii Folium

Epimedii Folium possesses many pharmacological activities including immunomodulation, anti-oxidation, and anti-tumor. Polysaccharides are the main components of Epimedii Folium, and their activities are closely related to the structure. The present study isolated a neutral polysaccharide(EPS-1-1) and an acidic polysaccharide(EPS-2-1) from the aqueous extract of Epimedii Folium through DEAE-52 cellulose anion-exchange chromatography and Sephadex G-100. The structures were characterized by chemical composition analysis, high-performance gel permeation chromatography(HPGPC), Fourier-transform infrared spectrometry(FT-IR), 1-phenyl-3-methyl-5-pyrazolone(PMP) derivatization, scanning electron microscopy(SEM), Congo red test, etc. The immunomodulatory activity of polysaccharides in vitro was determined by investigating the effects on the maturation of bone marrow-derived dendritic cells(BMDCs) and the release of inflammatory cytokines. According to the structural characterization analysis, EPS-1-1 was composed of fructose(Fuc), mannose(Man), ribose(Rib), rhamnose(Rha), glucose(Glc), galactose(Gal), xylose(Xyl), and arabinose(Ara) at 1.90∶0.67∶0.05∶0.08∶3.29∶1.51∶0.05∶0.37(molar ratio), while EPS-2-1 was mainly composed of Fuc, Man, Rha, glucuronic acid(GlcA), galacturonic acid(GalA), Glc, Gal, Xyl, and Ara at 5.25∶0.18∶0.32∶0.13∶1.14∶0.16∶0.55∶0.08∶0.2. EPS-1-1 and EPS-2-1 could promote the maturation and function of BMDCs through up-regulating the expression of MHC-Ⅱ, CD86, CD80, and CD40, and increasing the levels of inflammatory cytokines(IL-6, IL-12, and TNF-α) in vitro experiments, which suggested that EPS-1-1 and EPS-2-1 possessed good immunomodulatory activity.

The Role of bone marrow-derived dendritic Cells in a stressed beta2 adrenergic receptor knockout male mice during Chlamydia muridarum lung infection.

Recent studies have shown that Chlamydia muridarum causes a lung infection that resembles pneumonia of C. trachomatis in humans. However, the mechanism(s) of the infection is/are not well defined. Dendritic cells (DCs) play a significant role in protection against Chlamydia genital infections, but their role during stressful conditions is unknown. This study is to examine the role of bone marrow-derived dendritic cells (BMDCs) in beta2-adrenergic receptor (β2-AR) knockout (KO) male mice during C. muridarum lung infection. We hypothesized that the lack of β2-AR leads to decreased organ load of C. muridarum in mice lung infection. We also hypothesized that BMDCS from β2-AR KO mice restored the normal function of cytokine production and served as an antigen-presenting activity to CD4+T cells. Stressed and non-stressed C57BL/6J wildtype (WT) and β2-AR gene knockout mice will be infected. Lysates of lungs will be tested for isolation of C. muridarum. Cells will be for Differentiation and proliferation of BMDCs will be performed to detect cytokine production. Results should correspond to our working hypothesis, which includes the lack of (β2-AR) leads to decreased organ load of C. muridarum in lung infection. Results will show significant differences between stressed 2-AR KO and stressed of WT. Moreover, increased protective cytokine production in stressed 2-AR KO compared to decreased cytokines production in stressed WT will be observed. Our findings may suggest that mice lacking b2 AR have reverted to protective cytokine production to reduce infection, and the function of BMDCs as antigen-presenting cells will be restored in KO mice.

The effects of 1,25-dihydroxyvitamin D3 on markers related to the differentiation and maturation of bone marrow-derived dendritic cells from control and obese mice

Vitamin D has been reported to regulate the maturation and function of dendritic cells (DCs). Obesity was shown to be associated with the dysregulation of vitamin D metabolism and malfunction of DCs. We investigated the effects of in vitro 1,25(OH)2D3 treatment (0, 1, or 10 nM) on phenotype and expression of genes related to function of bone marrow-derived DCs (BMDCs) from control and obese mice. C57BL/6 N mice were fed a control or high-fat (10% or 45% kcal fat: CON or HFD) diets for 15 weeks. Differentiation toward DCs was induced with GM-CSF (20 ng/ml) and maturation was induced by LPS (50 ng/ml); 10 nM 1,25(OH)2D3 treatment inhibited BMDC differentiation (CD11c+) and decreased the percentage of mature DCs (MHCIIhighCD11c+ and CD86highCD11c+) in both CON and HFD groups. The Il10 expression in stimulated BMDCs from the CON group increased with the 10 nM 1,25(OH)2D3 treatment, but not in those from the HFD group. The Il12b mRNA levels in stimulated BMDCs were lower in the HFD group than in the CON group. In conclusion, lower levels of Cd 40, Cd83 and Il12 mRNA in LPS-stimulated BMDCs from obese mice suggest malfunction of DCs as antigen presenting cells. 1,25(OH)2D3 treatment inhibited the differentiation and maturation of BMDCs in both control and obese mice. Differential effects of 1,25(OH)2D3 on the expression of Il10 between control and obese mice suggest that regulation of immune response by vitamin D could be influenced by obesity.

Bone marrow dendritic cells deficient for CD40 and IL-23p19 are tolerogenic in vitro.

Objective(s):In addition to pro-inflammatory role, dendritic cells (DCs) can also be anti-inflammatory when they acquire tolerogenic phenotype. In this study we tested the role of CD40 and IL-23p19 in antigen presenting function of bone marrow-derived DCs (BMDCs) by comparing BMDCs derived from CD40 knockout (CD40KO-DCs) and IL-23p19 (IL-23p19KO-DCs) knockout mice with those from C57BL/6 mice (Cont-DCs). We have focused on CD40 and IL-23, as these molecules have well established pro-inflammatory roles in a number of autoimmune and inflammatory diseases. Materials and Methods:The expression of maturation markers MHC II and co-stimulatory molecules CD40, CD80, and CD86 was analyzed by flow cytometry, while the expression of CD40 and IL-23p19 was measured by RT-PCR. The capacity of BMDCs to activate CD4+ T cells was evaluated by 3H-thymidine incorporation, and the capacity of BMDCs to uptake antigen was evaluated using fluorescent OVA and flow cytometry. Results:The lack of CD40 or IL-23p19 had no effect on uptake of FITC-OVA by the DCs, confirming their immature phenotype. Moreover, CD40KO-DCs had significantly reduced capacity to stimulate proliferation of CD4+ T cells. CD4+ T cells activated by CD40KO-DCs and IL-23p19KO-DCs produced significantly less IFN-γ (P-value ≤0.05), while CD4+ T cells stimulated by IL-23p19KO-DCs produced less GM-CSF and more IL-10 than Cont-DCs. Conclusion:This study shows that CD40KO-DCs and IL-23p19KO-DCs have a marked tolerogenic potency in vitro. Future in vivo studies should determine if and to what extent DCs lacking CD40 or IL-23 have a potential to be useful in therapy of autoimmune inflammation.

The Protective Effects of the Ethyl Acetate Part of Er MiaoSan on Adjuvant Arthritis Rats by Regulating the Function of Bone Marrow-Derived Dendritic Cells.

The aim of this study was to evaluate the protective effects of Er Miao San (EMS) and the regulative function of bone marrow-derived dendritic cells (BMDCs) on adjuvant arthritis (AA) in rats. The ethyl acetate part of EMS (3 g/kg, 1.5 g/kg, and 0.75 g/kg) was orally administered from day 15 after immunization to day 29. The polyarthritis index and paw swelling were measured, the ankle joint pathological changes were observed using hematoxylin-eosin (HE) staining, and the spleen and thymus index were determined. Moreover, T and B cell proliferation were determined using the CCK-8 assay. The expression of BMDC surface costimulatory molecules and inflammatory factors were determined using flow cytometry and ELISA kits, respectively. Compared with the AA model rats, the ethyl acetate fraction of EMS obviously reduced paw swelling (from 1.0 to 0.7) and the polyarthritis index (from 12 to 9) (P < 0.01) and improved the severity of histopathology (P < 0.01). The treatment using ethyl acetate fraction of EMS significantly reduced the spleen and thymus index (P < 0.01) and inhibited T and B cell proliferation (P < 0.01). Moreover, EMS significantly modulated the expression of surface costimulatory molecules in BMDCs, including CD40, CD80, CD86, and major histocompatibility complex class II (MHC-II) (P < 0.01). The results also showed that the ethyl acetate part of EMS significant inhibited the levels of proinflammatory cytokines interleukin- (IL-) 23 tumor necrosis factor- (TNF-) α and inflammatory factor prostaglandin (PG) E2 in the supernatant of BMDCs. However, the level of anti-inflammatory cytokine IL-10 was significantly increased (P < 0.01). These results suggest that the ethyl acetate part of EMS has better protective effects on AA rats, probably by regulating the function of BMDCs and modulating the balance of cytokines.

Transcriptional Profiles of Murine Bone Marrow-Derived Dendritic Cells in Response to Peste des Petits Ruminants Virus.

Background: Peste des petits ruminants virus (PPRV) is the causative agent of PPR, which can cause an acute, highly contagious and fatal disease of sheep and goats, resulting in significant economic losses for commercial animal husbandry due to its high mortality and morbidity. As professional antigen-presenting cells, dendritic cells (DCs) play a unique role in innate immunity. This study aimed to gain a deeper understanding of the transcriptional response of bone marrow-derived dendritic cells (BMDCs) stimulated with PPRV. Results: Transcriptional profiling was performed using RNA sequencing. Herein, we reported that compared to untreatedBMDCs, 4492 differentially expressed genes (DEGs) were identified following PPRV stimulation, out of these DEGs 2311 were upregulated and 2181 were downregulated, respectively. A total of three gene ontology (GO) term clusters of biological process, cell component and molecular function were significantly enriched in 963 GO terms in the PPRV-stimulated BMDCs. These GO clusters were related to inflammatory response, cell division and vacuole, anchoring junction, positive regulation of cellular component and nucleoside binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of DEGs were enriched in a chemokine signaling pathway, protein processing in endoplasmic reticulum, cell cycle and mTOR signaling pathway. Additionally, identified DEGs of BMDCs were further validated by qRT-PCR and the results were in accordance with the change of the genes. This study suggested the effects of PPRV stimulation on the maturation and function of BMDCs. Conclusion: We found that the dramatic BMDCs transcriptome changes triggered were predominantly related to an inflammatory response and chemokine signaling pathway.

Restoration of stemness-high tumor cell-mediated suppression of murine dendritic cell activity and inhibition of tumor growth by low molecular weight oyster polysaccharide

Dendritic cells (DCs) play key regulatory roles in tumor immunity: increased activity of DCs infiltrating tumor tissues leads to enhancement of tumor immunity. Functions of DCs are also modulated by tumor cell-derived factors. Here, we investigated the effects of low molecular weight oyster polysaccharide (LMW-OPS) on differentiation and function of bone marrow-derived DCs (BMDCs) exposed to a conditioned medium (CM) obtained from spheres of stemness-high colorectal cancer cell lines CMT93 and CT26. The CM containing a detectable level of TGF-β1 was found to down-regulate the surface expression of major histocompatibility complex class II of BMDCs and to inhibit the potency of BMDCs to stimulate T cells. Those suppressions were partly restored and completely restored by addition of anti-TGF-β1 and LMW-OPS, respectively. Production of IFN-γ during allogeneic T cell responses was inhibited by the CM, whereas production of TGF-β1 was augmented by the CM. The IFN-γ profile was also reversed by addition of LMW-OPS. Nuclear translocation of β-catenin, but not that of NF-κB p65, was induced by TGF-β1. NF-κB p65 nuclear translocation, but not β-catenin nuclear translocation, was induced by LMW-OPS. Intraperitoneal injection of LMW-OPS significantly suppressed tumor growth in syngeneic tumor models using CMT93 and CT26 sphere cells, whereas it had no inhibitory effect on the proliferation of either cell line. The results demonstrated that LMW-OPS relieved stemness-high tumor cell-mediated suppression of BMDC function and indicated the in vivo anti-tumor activity of LMW-OPS in which re-stimulation of the activity of DCs infiltrating tumor tissues is presumed to be involved.

The immunosuppressive characteristics of FB1 by inhibition of maturation and function of BMDCs

Fumonisin B1 (FB1) is one kind of mycotoxins that has the neurotoxicity, carcinogenicity, hepatotoxicity and immunotoxicity produced by the fungus Fusarium verticillioides, which commonly infects corn and other crops and is harmful to animal and human health upon consumption of FB1-contaminated feed or food. However, the mechanism of immunotoxicity, especially the immunosuppression induced by FB1 is still unclear. The most pivotal cells in the induction of immune responses are dendritic cells (DCs). In this study, we used murine bone marrow-derived dendritic cells (BMDCs) as a model system to elucidate the effect of FB1 on the function of BMDCs through biological methods. We found that FB1 reversed the morphological changes and enhanced the endocytosis of FITC-dextran in LPS-treated BMDCs. At the same time, FB1 decreased the LPS-induced expressions of MHC II, C[1]D80 and CD86 molecules in BMDCs (p<0.05), as well as the T-cell stimulatory capacity of BMDCs (p<0.01). Moreover, the secretions of IL-6, IL-10 and IL-12, but not TNF-α induced by LPS exposure were suppressed by FB1 in a dose dependent (p<0.01). It was considered that the immunosuppressive effects of FB1 were mainly caused by changing the morphology and interfering with the process of antigen uptake, processing and presentation. The results highlighted that FB1 had the capacity to modulate the immune responses of BMDCs.

The Fifth Epidermal Growth Factor–like Region of Thrombomodulin Alleviates Murine Graft-versus-Host Disease in a G-Protein Coupled Receptor 15 Dependent Manner

Thrombomodulin (TM) exerts anti-inflammatory functions. We previously found that recombinant human soluble TM alleviated murine graft-versus-host disease (GVHD). Nevertheless, it is unclear how TM mediates its anti-inflammatory functions in GVHD. Here, we identified G-protein coupled receptor 15 (GPR15) expressed on T cells as a receptor/sensor of TM. The fifth region of epidermal growth factor–like domain of TM (TME5) bound GPR15 in vitro. TME5 prolonged survival of mice undergoing acute GVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT). TME5 increased regulatory T cells (Tregs) but decreased Th 1 proportions in targeted organs. TME5 suppressed allo-reaction in vitro in association with an increase in the number of induced Tregs. However, the anti-inflammatory function of TME5 was abolished when GPR15 knockout T cells were used as donor T cells. We further found that TME5 suppressed production of IL-6 in T cells, which probably facilitated differentiation of Tregs. Moreover, TME5 reduced activation of bone marrow–derived dendritic cells (BMDCs) and hampered function of BMDCs in inducing allo-reaction in vivo and in vitro. Our findings suggested that inducing Tregs as well as blocking activation of DCs in vivo by using TME5 is a potential therapeutic option for preventing GVHD in allo-HSCT.

Evaluation of the toxicity of iron-ion irradiation in murine bone marrow dendritic cells via increasing the expression of indoleamine 2,3-dioxygenase 1.

High linear energy transfer radiation is known to deposit higher energy in tissues and cause greater toxicity compared to low-LET irradiation. Local immunosuppression is frequently observed after irradiation (IR). Dendritic cells (DCs) play important roles in the initiation and maintenance of the immune response. The dysfunction of DCs contributes to tumor evasion and growth. However, molecular mechanisms underlying the establishment of immune tolerance induced by heavy ion IR through this DC population are poorly understood. Therefore, here we report our findings on the dysfunction of bone marrow-derived dendritic cells (BMDCs) induced by 1 Gy iron ion radiation and promotions of expressions of JNK1/2/3, indoleamine 2,3-dioxygenase 1 (IDO1), p-ERK1/2 and p38/MAPK; and decrease of IDO2, MHC class II, CD40, CD80 expressions and IFN-γ and TNF-α secretion after total-body IR in mice. JNK+IDO1+ BMDCs showed up-expression of p-ERK1/2 and p-p38/MAPK, reduced expression of MHC class II and CD80, and were not able to effectively stimulate allogeneic spleen T cells. The inhibition of IDO1 expressions could partly restore the function of BMDCs. In all, our study shows that elevated JNK and IDO1 expression induced by Fe ion IR could result in dysfunction of BMDCs via p-p38/MAPK and p-ERK1/2 signal pathway, and it may represent a new mechanism in radiation-induced immune tolerance.

Natural IgM Switches the Function of Lipopolysaccharide-Activated Murine Bone Marrow-Derived Dendritic Cells to a Regulatory Dendritic Cell That Suppresses Innate Inflammation.

We have previously shown that polyclonal natural IgM protects mice from renal ischemia/reperfusion injury (IRI) by inhibiting the reperfusion inflammatory response. We hypothesized that a potential mechanism involved IgM modulation of dendritic cells (DC), as we observed high IgM binding to splenic DC. To test this hypothesis, we pretreated bone marrow-derived DC (BMDC) with polyclonal murine or human IgM prior to LPS activation and demonstrated that 0.5 × 10(6) IgM/LPS-pretreated BMDC, when injected into wild-type C57BL/6 mice 24 h before renal ischemia, protect mice from developing renal IRI. We show that this switching of LPS-activated BMDC to a regulatory phenotype requires modulation of BMDC function that is mediated by IgM binding to nonapoptotic BMDC receptors. Regulatory BMDC require IL-10 and programmed death 1 as well as downregulation of CD40 and p65 NF-κB phosphorylation to protect in renal IRI. Blocking the programmed death ligand 1 binding site just before i.v. injection of IgM/LPS-pretreated BMDC or using IL-10 knockout BMDC fails to induce protection. Similarly, IgM/LPS-pretreated BMDC are rendered nonprotective by increasing CD40 expression and phosphorylation of p65 NF-κB. How IgM/LPS regulatory BMDC suppress in vivo ischemia-induced innate inflammation remains to be determined. However, we show that suppression is dependent on other in vivo regulatory mechanisms in the host, that is, CD25(+) T cells, B cells, IL-10, and circulating IgM. There was no increase in Foxp3(+) regulatory T cells in the spleen either before or after renal IRI. Collectively, these findings show that natural IgM anti-leukocyte Abs can switch BMDC to a regulatory phenotype despite the presence of LPS that ordinarily induces BMDC maturation.

Novel analysis of maturation of murine bone-marrow-derived dendritic cells induced by Ginkgo Seed Polysaccharides

Our understanding of the mechanisms of effect of Ginkgo Seed Polysaccharides (GSPs) on the immune system remains unclear. The aim of this work was to investigate the effect of GSPs on the maturation and function of bone-marrow-derived dendritic cells (BMDCs). The results demonstrate that GSP could exert positive immune modulation on the maturation and functions of BMDCs. This effect was evidenced by decreased changes of phagosome number inside BMDCs, decreased activity of acidic phosphatase (ACP), decreased phagocytosis of BMDCs, and increased changes of key membrane molecules on BMDCs. Upregulated production of cytokines IL-12 and TNF-α also was confirmed. Therefore, it can be concluded that GSPs can efficiently induce the maturation of BMDCs. Our exploration provides direct data and a rationale for potential application of GSPs as an immune enhancer in improving immunity and as a potent adjuvant in the design of DC-based vaccines.

MSCs inhibit bone marrow-derived DC maturation and function through the release of TSG-6

Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that are characterized by the ability to take up and process antigens and prime T cell responses. Mesenchymal stem cells (MSCs) are multipotent cells that have been shown to have immunomodulatory abilities, including inhibition of DC maturation and function in vivo and in vitro; however, the underlying mechanism is far from clear. In this study we found that MSCs can inhibit the maturation and function of bone marrow-derived DCs by releasing TSG-6. In the presence of MSCs, lower expression of mature DC surface phenotype (CD80, CD86, MHC-II, and CD11c) was observed. In addition, typical DC functions, such as the production of IL-12 and the ability to prime T cells, were decreased when co-cultured with MSCs. In contrast, knockdown of TSG-6 reduced the inhibitory effect of MSCs on DC. Moreover, we found that TSG-6 can suppress the activation of MAPKs, and NF-κB signaling pathways within DCs during Lipopolysaccharides (LPS) stimulation. In conclusion, we suggest that TSG-6 plays an important role in MSCs-mediated immunosuppressive effect on DC.

Age-Associated Changes in MicroRNA Expression in Bone Marrow Derived Dendritic Cells

MiRNAs have shown to regulate aging process at the level of cellular senescence, tissue aging, and lifespan of whole organism. Given that many miRNAs also function as important regulators of hematopoietic system as well as aging process, it is highly likely that miRNAs would be involved in the changes of myeloid function and differentiation during aging. Therefore, here we examine differential expression of miRNAs in aged myeloid lineage cells and assess if altered miRNA expression pattern would reflect the change of miRNA targets and related function. We demonstrated that the expressions of myelogenic miRNAs such as miR-155, miR-223, miR-146a, miR-146b, miR-132, miR-142-5p, and miR-142-3p were increased in aged bone marrow derived dendritic cells (BMDC) under normal and activated conditions. We also observed that the expressions of IRAK1 and TRAF6, the targets of miR-146a, and DC-SIGN, a target of miR-155 were diminished while miR-146a and miR-155 were augmented during aging. In addition, we found that the production of pro-inflammatory cytokines, which is mediated by the activation of NF-kB pathway via IRAK1 and TRAF6, was greatly reduced in aged BMDC. Taken together, our data reveal that age-associated changes occur in miRNA expression in BMDC, and this altered miRNA expression affects miRNA target expression and compromises BMDC function such as cytokine production during aging.

Methionine enkephalin (MENK) improved the functions of bone marrow-derived dendritic cells (BMDCs) loaded with antigen

The aim of this investigation is to look at whether MENK could improve antitumor effect of CD8+T cell elicited by BMDCs. We investigated the effects of MENK on the differentiation, maturation, and functions of murine BMDC loaded with Rac-1 antigens (RG) and CTL of tumor speci□c immune response elicited by the BMDC in vitro and in vivo. The production of cytokine IL-12 and TNF-αsecreted by BMDCs in the presence of MENK was assayed with ELISA and key surface markers of CD40,CD86, CD83 and MHC-II on the BMDCs were analyzed with use of flow cytometry (FCM). In addition, the activities to induce CD8+ T cell proliferation, along with displayed cytotoxicity of the CD8+T cells(CTL) by the BMDCs after treatment with MENK were determined with use of FCM as well as MTS. Our results indicated that MENK induced phenotypic and functional maturation of BMDC loaded with RG antigen, as evidenced by higher level of expression of key surface markers and more production of cytokines. Subsequently, the BMDC activated by MENK intensified immune responses mounted by CTL, resulting in stronger antitumor activity. Our results suggest that MENK could be working as an effective immune adjuvant in vaccine preparation for cancer fight and other immune related diseases. We concluded that MENK could be a positive immune modulator in the improved functions of BMDCs loaded with antigen as well as in CD8+T cell mediated anti-tumor responses.

Dendritic cell functional improvement in a preclinical model of lentiviral-mediated gene therapy for Wiskott–Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is a rare X-linked primary immunodeficiency caused by the defective expression of the WAS protein (WASP) in hematopoietic cells. It has been shown that dendritic cells (DCs) are functionally impaired in WAS patients and was−/− mice. We have previously demonstrated the efficacy and safety of a murine model of WAS gene therapy (GT), using stem cells transduced with a lentiviral vector. The aim of this study was to investigate whether GT can correct DC defects in was−/− mice. As DCs expressing WASP were detected in the secondary lymphoid organs of the treated mice, we tested the in vitro and in vivo function of bone marrow-derived DCs (BMDCs). The BMDCs showed efficient in vitro uptake of latex beads and Salmonella typhimurium. When BMDCs from the treated mice (GT BMDCs) and the was−/− mice were injected into wild type hosts, we found a higher number of cells that had migrated to the draining lymph nodes compared to mice injected with was−/− BMDCs. Finally, we found that OVA-pulsed GT BMDCs or vaccination with anti-DEC205 OVA fusion protein can efficiently induce antigen-specific T cell activation in vivo. These findings show that WAS GT significantly improves DC function, thus adding new evidence of the preclinical efficacy of lentiviral vector-mediated WAS GT.