Dopamine receptor agonist cabergoline promotes immunogenic phenotype in human monocyte-derived dendritic cells.

Dendritic cells (DCs) are known as antigen-presenting cells that are capable of regulating immune responses. DCs and T cells can interact mutually to induce antigen-specific T-cell responses. Cabergoline, which is a dopamine (DA) receptor agonist, seems to implement anti-inflammatory properties in the immune system, and therefore in the present study the impact of a DA receptor agonist cabergoline on the monocyte-derived DCs (moDCs) was assessed. Immature moDCs were treated with lipopolysaccharide to produce mature DCs (mDCs). The expression of DCs' related surface markers namely: CD11c, HLA-DR, and CD86 was measured by utilizing of flow cytometry. Real-time PCR was the technique of choice to determine the levels at which diverse inflammatory and anti-inflammatory factors in cabergoline-treated and control mDC groups were expressed. DCs treated with cabergoline displayed a significant decrease in CD86 and HLA-DR expression, markers linked to maturation and antigen presentation, respectively. In addition, the cabergoline-mDC group showed a considerable decline in terms of the levels at which IL-10, TGF-ß, and IDO genes were expressed, and an increase in the expression of TNF-α and IL-12 in comparison to the mDC control group. Our findings revealed that cabergoline as an immunomodulatory agent can relatively shift DCs into an immunogenic state, and there is a requirement for further investigations to evaluate the effects of cabergoline-treated DCs on the T cell responses in vitro, and also in various diseases including cancer in animal models.

Everolimus treatment enhances inhibitory immune checkpoint molecules' expression in monocyte-derived dendritic cells.

BACKGROUND: Antigen-specific T-cell immunity is provided by dendritic cells (DCs), which are specialized antigen-presenting cells. Furthermore, they establish a link between innate and adaptive immune responses. Currently, DC modification is a new approach for the therapy of several disorders. During solid organ transplantation, Everolimus, which is a mammalian target of rapamycin (mTOR) inhibitor, was initially utilized to suppress the immune system's functionality. Due to the intervention of Everolimus in various signaling pathways in cells and its modulatory properties on the immune system, this study aims to investigate the effect of treatment with Everolimus on the maturation and expression of immune checkpoint genes in monocyte-derived DCs. METHODS: To isolate monocytes from PBMCs, the CD14 marker was used via the MACS method. Monocytes were cultured and induced to differentiate into monocyte-derived DCs by utilizing GM-CSF and IL-4 cytokines. On the fifth day, immature DCs were treated with Everolimus and incubated for 24 h. On the sixth day, the flow cytometry technique was used to investigate the effect of Everolimus on the phenotypic characteristics of DCs. In the end, the expression of immune checkpoint genes in both the Everolimus-treated and untreated DCs groups was assessed using the real-time PCR method. RESULTS: The findings of this research demonstrated that the administration of Everolimus to DCs led to a notable rise in human leukocyte antigen (HLA)-DR expression and a decrease in CD11c expression. Furthermore, there was a significant increase in the expression of immune checkpoint molecules, namely CTLA-4, VISTA, PD-L1, and BTLA, in DCs treated with Everolimus. CONCLUSION: The findings of this study show that Everolimus can target DCs and affect their phenotype and function in order to shift them toward a partially tolerogenic state. However, additional research is required to gain a comprehensive understanding of the precise impact of Everolimus on the activation status of DCs.

Leptin/lipopolysaccharide-treated dendritic cell vaccine improved cellular immune responses in an animal model of breast cancer.

PURPOSE: In dendritic cells (DCs), leptin as an immune-regulating hormone, increases the IL-12 generation whereas it reduces the IL-10 production, thus contributing to TH1 cell differentiation. Using a murine model of breast cancer (BC), we evaluated the impacts of the Leptin and/or lipopolysaccharide (LPS)-treated DC vaccine on various T-cell-related immunological markers. MATERIALS AND METHODS: Tumors were established in mice by subcutaneously injecting 7 × 105 4T1 cells into the right flank. Mice received the DC vaccines pretreated with Leptin, LPS, and both Leptin/LPS, on days 12 and 19 following tumor induction. The animals were sacrificed on day 26 and after that the frequency of the splenic cytotoxic T lymphocytes (CTLs) and TH1 cells; interferon gamma (IFN-γ), interleukin 12 (IL-12) and tumor growth factor beta (TGF-ß) generation by tumor lysate-stimulated spleen cells, and the mRNA expression of T-bet, FOXP3 and Granzyme B in the tumors were measured with flow cytometry, ELISA and real-time PCR methods, respectively. RESULTS: Leptin/LPS-treated mDC group was more efficient in blunting tumor growth (p = .0002), increasing survival rate (p = .001), and preventing metastasis in comparison with the untreated tumor-bearing mice (UT-control). In comparison to the UT-control group, treatment with Leptin/LPS-treated mDC also significantly increased the splenic frequencies of CTLs (p < .001) and TH1 cells (p < .01); promoted the production of IFN-γ (p < .0001) and IL-12 (p < .001) by splenocytes; enhanced the T-bet (p < .05) and Granzyme B (p < .001) expression, whereas decreased the TGF-ß and FOXP3 expression (p < .05). CONCLUSION: Compared to the Leptin-treated mDC and LPS-treated mDC vaccines, the Leptin/LPS-treated mDC vaccine was more effective in inhibiting BC development and boosting immune responses against tumor.

Glyburide-treated human monocyte-derived dendritic cells loaded with insulin represent tolerogenic features with anti-inflammatory responses and modulate autologous T cell responses in vitro.

Tolerogenic dendritic cells (TolDCs) are attractive therapeutic options for autoimmune disorders because they suppress autologous T-cell responses. Dendritic cells (DCs) are equipped with pattern recognition receptors (PRR), including nucleotide-binding and oligomerization domain-like receptors (NLRs) such as NLRP3. Abnormal NLRP3 activation has been reported to be correlated with the occurrence of autoimmune disorders. Accordingly, we hypothesized that glyburide treatment of DCs by blocking the ATP-sensitive K+ (kATP) channels generates TolDCs by inhibiting NLRP3. Insulin was even loaded on a group of glyburide-treated mature DCs (mDCs) to investigate the antigen (Ag) loading effects on glyburide-treated mDCs' phenotypical and functional features. Consequently, T lymphocytes' mediated responses ensuing co-culture of them with control mDCs, insulin loaded and unloaded glyburide treated mDCs were evaluated to determine generated TolDCs' capacity in inhibition of T cell responses that are inducer of destruction in insulin-producing pancreatic beta cells in Type 1 Diabetes Mellitus (T1DM). Our findings indicated that glyburide generates desirable TolDCs with decreased surface expression of maturation and Ag presentation related markers and diminished level of inflammatory but increased level of anti-inflammatory cytokines, which even insulin loading demonstrated more anti-inflammatory functions. In addition, co-cultured T cells showed regulatory or T helper 2 phenotype instead of T helper 1 features. Our findings suggested that insulin-loaded and unloaded glyburide-treated DCs are promising therapeutic approaches for autoimmune patients, specifically DCs loaded with insulin for T1DM patients. However, further research is required before this technique can be applied in clinical practice.

siRNA-Mediated B7H7 Knockdown in Gastric Cancer Lysate-Loaded Dendritic Cells Amplifies Expansion and Cytokine Secretion of Autologous T Cells.

BACKGROUND: Gastric cancer, ranked as the fifth most common cancer worldwide, presents multiple treatment challenges. These obstacles often arise due to cancer stem cells, which are associated with recurrence, metastasis, and drug resistance. While dendritic cell (DC)-based immunotherapy has shown promise as a therapeutic strategy, its efficacy can be limited by the tumor microenvironment and certain inhibitory immune checkpoint molecules, such as B7H7. SiRNA-medicated knockdown of B7H7 in tumor cell lysate-pulsed DCs can increase cytokine secretion and autologous T lymphocyte expansion. This study aimed to evaluate the impact of B7H7 suppression in gastric cancer cell lysate-pulsed DCs on the stimulatory potential of autologous CD3+ T lymphocytes. METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated and monocytes were obtained; then, they were differentiated to immature DCs (iDCs) by GM-CSF and IL-4. Tumor cell lysates from human gastric cancer cell lines were harvested, and iDCs were transformed into mature DCs (mDCs) by stimulating iDCs with tumor cell lysate and lipopolysaccharide. B7H7-siRNA was delivered into mDCs using electroporation, and gene silencing efficiency was assessed. The phenotypic characteristics of iDCs, mDCs, and B7H7-silenced mDCs were evaluated using specific surface markers, an inverted light microscope, and flow cytometry. CD3+ T cells were isolated via magnetically activated cell sorting. They were labeled with CFSE dye and co-cultured with mDCs and B7H7-silenced mDCs to evaluate their ability to induce T-cell proliferation. T-cell proliferation was assessed using flow cytometry. The concentration of TGF-ß, IL-4, and IFN-γ secreted from CD3+ T cells in the co-cultured supernatant was evaluated to investigate the cytokine secretory activity of the cells. RESULTS: Transfection of B7H7 siRNA into mDCs was performed in optimal conditions, and the siRNA transfection effectively reduced B7H7 mRNA expression in a dose-dependent manner. SiRNA-mediated B7H7 knockdown in mDCs enhanced maturation and activation of the DCs, as demonstrated by an increased surface expression of CD11c, CD86, and CD40. Co-culture experiments revealed that B7H7-silenced mDCs had more capacity to induce T cell proliferation compared to non-transfected mDCs. The cytokine production patterns of T cells were also altered. Upon examining the levels of TGF-ß, IL-4, and IFN-γ released by CD3+ T cells in the co-culture supernatant, we found that silencing B7H7 in mDCs resulted in a rise in IL-4 secretion and a reduction in TGF-ß levels compared to mDCs that were not transfected. CONCLUSIONS: The study found that suppressing B7H7 expression in DCs significantly enhances their maturation and stimulatory activity when exposed to gastric cancer cell lysate. These B7H7-silenced DCs can substantially increase cytokine production and promote co-cultured T-cell expansion. Consequently, inhibiting B7H7 in DCs may offer a practical strategy to enhance the ability of DCs to initiate T lymphocyte responses and improve the effectiveness of DC-based cell therapy for cancer 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.

What is the context?Multiple disorders, including different infectious and autoimmune diseases and cancers, have affected many individuals all around the world. One of the main methods for combating such diseases is immunotherapy based on the dendritic cell (DC) vaccine. DCs are the most potent antigen-presenting cells for developing T lymphocytes' potential to eliminate external and internal harmful factors. Manipulating DCs' different signaling pathways, such as activating or blocking inhibitory or activatory pathways, based on our purpose is a great method for achieving efficient DC vaccines. The signal transducer and activator of transcription (STAT) is a protein with six subtypes that exists in DCs and conducts specific signaling pathways. Changing the activity of each STAT via various methods and drugs can affect DCs differently. Furthermore, each DC-existing STAT can play a specific role in establishing a special kind of disease. Thus, STAT proteins and their related signaling pathways have attracted many scientists' attention.What does the review highlight?We provide a comprehensive overview of different STATs' roles in DC subsets. Moreover, we conducted this review to identify if DC-associated STATs have any role in starting a special kind of disease. The effects of different drugs on STATs in DCs were also investigated.What is the impact?Generalabsly, STAT1, STAT2, and STAT4 with activatory roles, STAT3 with inhibitory roles, and STAT5 and STAT6 with both inhibitory and activatory roles can affect DCs in different conditions. Targeting different STATs in DCs with specific drugs contributes to alleviating various disease symptoms.

Regulation of Dendritic Cell Functions by Vitamins as Promising Therapeutic Strategy for Immune System Disorders.

A functional immune system is crucial for a healthy life, protecting from infections, tumors, or autoimmune disorders; these are accomplished by the interaction between various immune cells. Nourishment, particularly micronutrients, are very important components in the immune system balance, therefore this review emphasizes the vitamins (D, E, A, C) and Dendritic cells' subsets due to vitamins' roles in immune processes, especially on dendritic cells' functions, maturation, and cytokine production. Current studies reveal significant benefits related to vitamins, including vitamin E, which can contribute to the control of dendritic cells' function and maturation. Furthermore, vitamin D plays an immunoregulatory and anti-inflammatory role in the immune system. Metabolite of vitamin A which is called retinoic acid leads to T cells' differentiation to T helper 1 or T helper 17, so low levels of this vitamin exacerbate the menace of infectious diseases, and vitamin C has anti-oxidant effects on dendritic cells and modulate their activation and differentiation program. Additionally, the correlation between the amount of vitamin and the occurrence or progression of allergic diseases and autoimmunity disorders is discussed according to the results of previous studies.