Current Paradigms of Tolerogenic Dendritic Cells and Clinical Implications for Systemic Lupus Erythematosus

Dendritic cells: the yin and yang in disease progression

Dendritic cells (DCs) are antigen presenting cells that link innate and adaptive immunity. DCs have been historically considered as the most effective and potent cell population to capture, process and present antigens to activate naïve T cells and originate favorable immune responses in many diseases, such as cancer. However, in the last decades, it has been observed that DCs not only promote beneficial responses, but also drive the initiation and progression of some pathologies, including inflammatory bowel disease (IBD). In line with those notions, different therapeutic approaches have been tested to enhance or impair the concentration and role of the different DC subsets. The blockade of inhibitory pathways to promote DCs or DC-based vaccines have been successfully assessed in cancer, whereas the targeting of DCs to inhibit their functionality has proved to be favorable in IBD. In this review, we (a) described the general role of DCs, (b) explained the DC subsets and their role in immunogenicity, (c) analyzed the role of DCs in cancer and therapeutic approaches to promote immunogenic DCs and (d) analyzed the role of DCs in IBD and therapeutic approaches to reduced DC-induced inflammation. Therefore, we aimed to highlight the "yin-yang" role of DCs to improve the understand of this type of cells in disease progression.

Vitamin D3 mitigates autoimmune inflammation caused by activation of myeloid dendritic cells in SLE

Systemic lupus erythematosus (SLE) is an autoimmune disease in which defective T cells, immune complex deposition and other immune system alterations contribute to pathological changes of multiple organ systems. The vitamin D metabolite c is a critical immunomodulator playing pivotal roles in the immune system. Epidemiological evidence indicates that vitamin D deficiency is correlated with the severity of SLE. Our aim is to investigate the effects of 1,25(OH)2D3 (VitD3) on the activation of myeloid dendritic cells (mDCs) by autologous DNA-containing immune complex (DNA-ICs), and the effects of VitD3 on immune system balance during SLE. We purified DNA-ICs from the serum of SLE patients and isolated mDCs from normal subjects. In vitro studies showed that DNA-ICs were internalized and consumed by mDCs. VitD3 blocked the effects of DNA-ICs on RelB, IL-10 and TNF-α in mDCs. Further analysis indicated that DNA-ICs stimulated histone acetylation in the RelB promoter region, which was inhibited by VitD3. Knockdown of the histone deacetylase 3 gene (HDAC3) blocked these VitD3-mediated effects. Co-culture of mDCs and CD4+ T cells showed that VitD3 inhibited multiple processes mediated by DNA-ICs, including proliferation, downregulation of IL-10, TGF-β and upregulation of TNF-α. Moreover, VitD3 could also reverse the effects of DNA-IC-induced imbalance of CD4+  CD127-  Foxp3+ T cells and CD4+  IL17+ T cells. Taken together, our results indicated that autologous DNA-ICs stimulate the activation of mDCs in the pathogenesis of SLE, and VitD3 inhibits this stimulatory effects of DNA-ICs by negative transcriptional regulation of RelB gene and maintaining the Treg/Th17 immune cell balance. These results suggest that vitamin D may have therapeutic value for the treatment of SLE.

Immuno-metabolic dendritic cell vaccine signatures associate with overall survival in vaccinated melanoma patients

Efficacy of cancer vaccines remains low and mechanistic understanding of antigen presenting cell function in cancer may improve vaccine design and outcomes. Here, we analyze the transcriptomic and immune-metabolic profiles of Dendritic Cells (DCs) from 35 subjects enrolled in a trial of DC vaccines in late-stage melanoma (NCT01622933). Multiple platforms identify metabolism as an important biomarker of DC function and patient overall survival (OS). We demonstrate multiple immune and metabolic gene expression pathway alterations, a functional decrease in OCR/OXPHOS and increase in ECAR/glycolysis in patient vaccines. To dissect molecular mechanisms, we utilize single cell SCENITH functional profiling and show patient clinical outcomes (OS) correlate with DC metabolic profile, and that metabolism is linked to immune phenotype. With single cell metabolic regulome profiling, we show that MCT1 (monocarboxylate transporter-1), a lactate transporter, is increased in patient DCs, as is glucose uptake and lactate secretion. Importantly, pre-vaccination circulating myeloid cells in patients used as precursors for DC vaccine generation are significantly skewed metabolically as are several DC subsets. Together, we demonstrate that the metabolic profile of DC is tightly associated with the immunostimulatory potential of DC vaccines from cancer patients. We link phenotypic and functional metabolic changes to immune signatures that correspond to suppressed DC differentiation.

Syringaldehyde ameliorates mouse arthritis by inhibiting dendritic cell maturation and proinflammatory cytokine secretion

Syringaldehyde (SD), a kind of flavonoid polyphenolic small molecule compound, has the antioxidant and anti-inflammatory properties. But it is unknown whether SD has properties on the treatment of rheumatoid arthritis (RA) by modulating dendritic cells (DCs). We explored the effect of SD on the maturation of DCs in vitro and in vivo. The results showed that SD significantly down-regulated the expression of CD86, CD40 and MHC II, decreased the secretion of TNF-α, IL-6, IL-12p40 and IL-23, and increased IL-10 secretion and antigen phagocytosis in vitro induced by lipopolysaccharides in a dose-dependent manner through reducing the activation of MAPK/NF-κB signaling pathways. SD also significantly inhibited the expression of CD86, CD40 and MHC II on DCs in vivo. Moreover, SD suppressed the expression of CCR7 and the in vivo migration of DCs. In arthritis mouse models induced by λ-carrageenan and complete Freund's adjuvant, SD significantly alleviated paw and joint oedema, reduced the levels of pro-inflammatory cytokines TNF-α and IL-6 and increased the level of IL-10 in serum. Interestingly, SD significantly decreased the numbers of type I helper T cells (Th1), Th2, Th17 and Th17/Th1-like (CD4⁺IFN-γ⁺IL-17A⁺), but increased the numbers of regulatory T cells (Tregs) in spleens of mice. Importantly, the numbers of CD11c⁺IL-23⁺ and CD11c⁺IL-6⁺ cells were negatively correlated with the numbers of Th17 and Th17/Th1-like. These results suggested that SD ameliorated mouse arthritis through inhibiting the differentiation of Th1, Th17 and Th17/Th1-like and promoting the generation of Tregs via regulation of DC maturation.

Attenuation of OX40 signaling suppression by age disrupts peripheral deletion of CD4+ T cells specific for the epidermal autoantigen desmoglein 3

Various autoimmune responses increase with age, but the underlying mechanism is not clear. In this study, we used CD4⁺ T cells expressing a transgenic T cell receptor specific for desmoglein 3 (Dsg3), which is the target antigen of the autoimmune bullous disease pemphigus vulgaris, to examine how peripheral immunological tolerance against pathogenic autoreactive CD4⁺ T cells changes with age. Dsg3-specific T cells were deleted within 14 days after adoptive transfer into young mice (8 weeks old), while they escaped deletion when transferred into older mice over 42 weeks old. Dsg3-specific T cells produced higher levels of the proinflammatory cytokine IFN-γ in aged mice than in young mice. In addition, the expression levels of both OX40 and Birc5, which are important for cell survival in T cell clonal proliferation, were higher in aged than in young mice. The dysfunction in suppressing proinflammatory cytokine secretion and Birc5 upregulation in Dsg3-specific autoreactive T cells may reflect an aspect of the preliminary steps in autoimmune disease development in the aged population. Understanding this mechanism may lead to better risk evaluation of autoimmune disease development and to onset prevention.

TIM-3 increases the abundance of type-2 dendritic cells during Leishmania donovani infection by enhancing IL-10 production via STAT3

The outcome of the disease visceral leishmaniasis (VL), caused by Leishmania donovani (LD), largely relies on the relative dominance of host-protective type-1 T helper (Th1) cell response versus disease-promoting type-2 T helper (Th2) cell response. The Th1 and Th2 responses, in turn, are believed to be elicited by type-1 conventional dendritic cells (cDC1) and type-2 conventional DCs (cDC2), respectively. However, it is still unknown which DC subtype (cDC1 or cDC2) predominates during chronic LD infection and the molecular mechanism governing such occurrence. Here we report that in chronically infected mice, the splenic cDC1-cDC2 balance shifted toward the cDC2 subtype and that the receptor T cell immunoglobulin and mucin protein-3 (TIM-3) expressed by DCs played a key role in mediating this effect. Transfer of TIM-3-silenced DCs in fact prevented the predominance of the cDC2 subtype in mice with chronic LD infection. We also found that LD actually upregulated TIM-3 expression on DCs by triggering a TIM-3-mediated signaling pathway STAT3 (signal transducer and activator of transcription 3)→interleukin (IL)-10→c-Src→transcription factors Ets1, Ets2, USF1, and USF2. Notably, TIM-3 promoted STAT3 activation via a non-receptor tyrosine kinase Btk. Adoptive transfer experiments further demonstrated a critical role for STAT3-driven TIM-3 upregulation on DCs in increasing cDC2 abundance in chronically infected mice, which ultimately aided disease pathogenesis by augmenting Th2 responses. These findings document a new immunoregulatory mechanism contributing to disease pathology during LD infection and define TIM-3 as a key mediator of this process.

Immunosuppressive Polymeric Nanoparticles Targeting Dendritic Cells Alleviate Lupus Disease in Fcgr2b-/- Mice by Mediating Antigen-Specific Immune Tolerance

Dendritic cells (DCs) are the most potent antigen-presenting cells that have multifaceted functions in the control of immune activation and tolerance. Hyperresponsiveness and altered tolerogenicity of DCs contribute to the development and pathogenesis of system lupus erythematosus (SLE); therefore, DC-targeted therapies aimed at inducing specific immune tolerance have become of great importance for the treatment of SLE. This study developed a new nanoparticle (NP) containing a biodegradable PDMAEMA-PLGA copolymer for target-oriented delivery to DCs in situ. PDMAEMA-PLGA NPs provided sustained drug release and exhibited immunosuppressive activity in FLT3L and GM-CSF-derived bone marrow in conventional DCs (BM-cDCs). PDMAEMA-PLGA NPs improved dexamethasone capability to convert wild-type and Fcgr2b^-/- BM-cDCs from an immunogenic to tolerogenic state, and BM-cDCs treated with dexamethasone-incorporated PDMAEMA-PLGA NPs (Dex-NPs) efficiently mediated regulatory T cell (Treg) expansion in vitro. Dex-NP therapy potentially alleviated lupus disease in Fcgr2b^-/- mice by mediating Foxp3⁺ Treg expansion in an antigen-specific manner. Our findings substantiate the superior efficacy of DC-targeted therapy using the PDMAEMA-PLGA NP delivery system and provide further support for clinical development as a potential therapy for SLE. Furthermore, PDMAEMA-PLGA NP may be a versatile platform for DC-targeted therapy to induce antigen-specific immune tolerance to unwanted immune responses that occur in autoimmune disease, allergy, and transplant rejection.

The role of tolerogenic dendritic cells in systematic lupus erythematosus progression and remission

Systematic lupus erythematosus (SLE) is an autoimmune disease reflecting an imbalance between effector and regulatory immune responses. Dendritic cells (DC) are a link between innate and adaptive immunity. Inflammatory DCs (inflDC) can initiate and trigger lymphocyte responses in SLE with over-expression of surface molecules and pro-inflammatory cytokine, including Interferon (IFN) α, Interleukin (IL) 1α, IL-1β, and IL-6, resulting in the overreaction of T helper cells (Th), and B cells immune responses. On the opposite side, tolerogenic DCs (tolDC) express inhibitory interacting surface molecules and repressive mediators, such as IL-10, Transforming growth factor beta (TGF-β), and Indoleamine 2, 3-dioxygenase (IDO), which can maintain self-tolerance in SLE by induction of regulatory T cells (Treg), T cells deletion and anergy. Hence, tolDCs can be a therapeutic candidate for patients with SLE to suppress their systematic inflammation. Recent pre-clinical and clinical studies showed the efficacy of tolDCs therapy in autoimmune diseases. In this review, we provide a wide perspective on the effect of inflDCs in promoting inflammation and the role of tolDC in the suppression of immune cells' overreaction in SLE. Furthermore, we reviewed the finding of clinical trials and experimental studies related to autoimmune diseases, particularly SLE.

A Therapeutic Nanovaccine that Generates Anti-Amyloid Antibodies and Amyloid-specific Regulatory T Cells for Alzheimer's Disease

Alzheimer's disease (AD), the most common cause of dementia, is a complex condition characterized by multiple pathophysiological mechanisms including amyloid-β (Aβ) plaque accumulation and neuroinflammation in the brain. The current immunotherapy approaches, such as anti-Aβ monoclonal antibody (mAb) therapy, Aβ vaccines, and adoptive regulatory T (Treg) cell transfer, target a single pathophysiological mechanism, which may lead to unsatisfactory therapeutic efficacy. Furthermore, Aβ vaccines often induce T helper 1 (Th1) cell-mediated inflammatory responses. Here, a nanovaccine composed of lipid nanoparticles loaded with Aβ peptides and rapamycin is developed, which targets multiple pathophysiological mechanisms, exhibits the combined effects of anti-Aβ antibody therapy and adoptive Aβ-specific Treg cell transfer, and can overcome the limitations of current immunotherapy approaches for AD. The Nanovaccine effectively delivers rapamycin and Aβ peptides to dendritic cells, produces both anti-Aβ antibodies and Aβ-specific Treg cells, removes Aβ plaques in the brain, alleviates neuroinflammation, prevents Th1 cell-mediated excessive immune responses, and inhibits cognitive impairment in mice. The nanovaccine shows higher efficacy in cognitive recovery than an Aβ vaccine. Unlike anti-Aβ mAb therapy and adoptive Treg cell transfer, both of which require complicated and costly manufacturing processes, the nanovaccine is easy-to-prepare and cost-effective. The nanovaccines can represent a novel treatment option for AD.

Tolerogenic Dendritic Cells Induce Apoptosis-Independent T Cell Hyporesponsiveness of SARS-CoV-2-Specific T Cells in an Antigen-Specific Manner

Although the global pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still ongoing, there are currently no specific and highly efficient drugs for COVID-19 available, particularly in severe cases. Recent findings demonstrate that severe COVID-19 disease that requires hospitalization is associated with the hyperactivation of CD4⁺ and CD8⁺ T cell subsets. In this study, we aimed to counteract this high inflammatory state by inducing T-cell hyporesponsiveness in a SARS-CoV-2-specific manner using tolerogenic dendritic cells (tolDC). In vitro-activated SARS-CoV-2-specific T cells were isolated and stimulated with SARS-CoV-2 peptide-loaded monocyte-derived tolDC or with SARS-CoV-2 peptide-loaded conventional (conv) DC. We demonstrate a significant decrease in the number of interferon (IFN)-γ spot-forming cells when SARS-CoV-2-specific T cells were stimulated with tolDC as compared to stimulation with convDC. Importantly, this IFN-γ downmodulation in SARS-CoV-2-specific T cells was antigen-specific, since T cells retain their capacity to respond to an unrelated antigen and are not mediated by T cell deletion. Altogether, we have demonstrated that SARS-CoV-2 peptide-pulsed tolDC induces SARS-CoV-2-specific T cell hyporesponsiveness in an antigen-specific manner as compared to stimulation with SARS-CoV-2-specific convDC. These observations underline the clinical potential of tolDC to correct the immunological imbalance in the critically ill.

Distinct metabolic states guide maturation of inflammatory and tolerogenic dendritic cells

Cellular metabolism underpins immune cell functionality, yet our understanding of metabolic influences in human dendritic cell biology and their ability to orchestrate immune responses is poorly developed. Here, we map single-cell metabolic states and immune profiles of inflammatory and tolerogenic monocytic dendritic cells using recently developed multiparametric approaches. Single-cell metabolic pathway activation scores reveal simultaneous engagement of multiple metabolic pathways in distinct monocytic dendritic cell differentiation stages. GM-CSF/IL4-induce rapid reprogramming of glycolytic monocytes and transient co-activation of mitochondrial pathways followed by TLR4-dependent maturation of dendritic cells. Skewing of the mTOR:AMPK phosphorylation balance and upregulation of OXPHOS, glycolytic and fatty acid oxidation metabolism underpin metabolic hyperactivity and an immunosuppressive phenotype of tolerogenic dendritic cells, which exhibit maturation-resistance and a de-differentiated immune phenotype marked by unique immunoregulatory receptor signatures. This single-cell dataset provides important insights into metabolic pathways impacting the immune profiles of human dendritic cells.

Assessing metabolic activity within single cells rather than at a population level has a number of advantages. Here, the authors use a flow and mass cytometry based approach that assess the metabolic differences between populations of human immune stimulatory and tolerogenic dendritic cells.

Gut Barrier Damage and Gut Translocation of Pathogen Molecules in Lupus, an Impact of Innate Immunity (Macrophages and Neutrophils) in Autoimmune Disease

The gut barrier is a single cell layer that separates gut micro-organisms from the host, and gut permeability defects result in the translocation of microbial molecules from the gut into the blood. Despite the silent clinical manifestation, gut translocation of microbial molecules can induce systemic inflammation that might be an endogenous exacerbating factor of systemic lupus erythematosus. In contrast, circulatory immune-complex deposition and the effect of medications on the gut, an organ with an extremely large surface area, of patients with active lupus might cause gut translocation of microbial molecules, which worsens lupus severity. Likewise, the imbalance of gut microbiota may initiate lupus and/or interfere with gut integrity which results in microbial translocation and lupus exacerbation. Moreover, immune hyper-responsiveness of innate immune cells (macrophages and neutrophils) is demonstrated in a lupus model from the loss of inhibitory Fc gamma receptor IIb (FcgRIIb), which induces prominent responses through the cross-link between activating-FcgRs and innate immune receptors. The immune hyper-responsiveness can cause cell death, especially apoptosis and neutrophil extracellular traps (NETosis), which possibly exacerbates lupus, partly through the enhanced exposure of the self-antigens. Leaky gut monitoring and treatments (such as probiotics) might be beneficial in lupus. Here, we discuss the current information on leaky gut in lupus.

Tuberculosis and Autoimmunity

Tuberculosis remains a common and dangerous chronic bacterial infection worldwide. It is long-established that pathogenesis of many autoimmune diseases is mainly promoted by inadequate immune responses to bacterial agents, among them Mycobacterium tuberculosis. Tuberculosis is a multifaceted process having many different outcomes and complications. Autoimmunity is one of the processes characteristic of tuberculosis; the presence of autoantibodies was documented by a large amount of evidence. The role of autoantibodies in pathogenesis of tuberculosis is not quite clear and widely disputed. They are regarded as: (1) a result of imbalanced immune response being reactive in nature, (2) a critical part of TB pathogenicity, (3) a beginning of autoimmune disease, (4) a protective mechanism helping to eliminate microbes and infected cells, and (5) playing dual role, pathogenic and protective. There is no single autoimmunity-mechanism development in tuberculosis; different pathways may be suggested. It may be excessive cell death and insufficient clearance of dead cells, impaired autophagy, enhanced activation of macrophages and dendritic cells, environmental influences such as vitamin D insufficiency, and genetic polymorphism, both of Mycobacterium tuberculosis and host.

Metabolic Reprogramming of Innate Immune Cells as a Possible Source of New Therapeutic Approaches in Autoimmunity

Immune cells undergo different metabolic pathways or immunometabolisms to interact with various antigens. Immunometabolism links immunological and metabolic processes and is critical for innate and adaptive immunity. Although metabolic reprogramming is necessary for cell differentiation and proliferation, it may mediate the imbalance of immune homeostasis, leading to the pathogenesis and development of some diseases, such as autoimmune diseases. Here, we discuss the effects of metabolic changes in autoimmune diseases, exerted by the leading actors of innate immunity, and their role in autoimmunity pathogenesis, suggesting many immunotherapeutic approaches.

Role of the innate and adaptive immune responses in the pathogenesis of systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE), the most common form of lupus, is a multisystemic rheumatic disease with different clinical features that generally affect women of childbearing age. The common symptoms of SLE are very similar to other autoimmune and non-autoimmune disorders, thereby it is known as a thousand faces disease. In this article, we are going to discuss some of the most updated information about immune system-related factors, cells, and cytokines involved in SLE pathogenesis.

METHODS

Different electronic databases, especially PubMed/MEDLINE, Scopus, and Google Scholar, were searched to review and analyze relevant literature on the role of innate and adaptive immune cells and cytokines in the pathogenesis of SLE. A search for relevant literature was accomplished using various keywords including systemic lupus erythematosus, apoptosis, autoantibodies, immunopathogenesis of SLE, adaptive and innate immune cells, inflammatory cytokines, hormones, etc. RESULTS AND CONCLUSION: The most important characteristic of SLE is the production of antibodies against different nuclear autoantigens like double-strand DNA and RNA. The depositions of the immune complexes (ICs) that are generated between autoantibodies and autoantigens, along with aberrant clearance of them, can lead to permanent inflammation and contribute to tissue or organ damage. Related mechanisms underlying the initiation and development of SLE have not been clarified yet. Although, defects in immune tolerance, enhanced antigenic load, hyperactivity of T cells, and inappropriate regulation of B cells contribute to the pathogenic autoantibodies generation. Besides, sex hormones that influence the immune system seem to act as triggers or protectors of SLE development.

Trichostatin A inhibits dendritic cell maturation through down-regulating NF-κ B (p65) pathway

BACKGROUND

Recent evidence suggested that histone deacetylase inhibitor (HDACi) could inhibit dendritic cell (DC) maturation. However, the mechanism is unclear. Here, we aimed to study whether Trichostatin A (TSA), the most widely studied HDACi, inhibits the maturation of DCs by down-regulating NF-κB (p65) pathway.

METHODS AND RESULTS

Mouse bone marrow-derived DCs were cultured. Lipopolysaccharide (LPS) was applied as stimulation for maturation. Triptolide (TTL) was applied as p65 inhibitor. Microphotography and flow cytometry showed that TSA and p65 inhibitor separately inhibited the maturation of DCs stimulated by LPS from the aspects of cell morphology and cell phenotype. Mixed lymphocyte reaction test and ELISA showed that TSA and p65 inhibitor synergistically inhibited the proliferation of T lymphocytes stimulated by DCs, reduced the secretion of pro-inflammatory cytokine IL-12 and elevated the secretion of anti-inflammatory cytokine IL-10. Western blot and RT-qPCR showed that TSA down-regulated the expression of phosphorylated IκBα, phosphorylated-p65, Ikkβ and Ikkγ, suggesting TSA down-regulates NF-κB (p65) pathway.

CONCLUSIONS

TSA inhibits DC maturation through down-regulating NF-κB (p65) pathway.

Inhibitory effects of tolerogenic probiotics on migratory potential of lupus patient-derived DCs

Objectives

The present in vitro study aimed to evaluate whether Lactobacillus delbrueckii and Lactobacillus rhamnosus treatments can induce regulatory phenotype, together with modulating the expression of chemokine receptors (CRs) in dendritic cells (DCs). The CRs of DCs have been found to be involved in the pathogenesis of Systemic lupus erythematosus (SLE) through directing recruitment and migration of immune cells.

Materials and Methods

In brief, monocytes of patients with SLE and healthy donors were isolated and differentiated to regulatory or inflammatory mature DCs through treatment with L. delbrueckii, L. rhamnosus, mixed probiotics, and LPS.

Results

FACScan analysis showed that the expression of CRs including CXCR3, CCR5, CCR4, and CCR3, was significantly reduced in all probiotic-treated groups of SLE and healthy (control) donors when compared with the LPS treated group.

Conclusion

The results demonstrated that tolerogenic probiotics could prevent or decrease the expression of inflammatory CRs on the surface of tolerogenic DCs during the maturation process.

The high expression of miR-564 in patients with systemic lupus erythematosus promotes differentiation and maturation of DC cells by negatively regulating TP53 expression in vitro

BACKGROUND

miRNA is involved in the occurrence and progression of systemic lupus erythematosus (SLE), but the regulatory effect of miRNA on dendritic cells in SLE patients is still unclear.

MATERIAL AND METHODS

Bioinformatics methods were used to analyze the differentially expressed miRNA and its target genes in SLE patients. In vitro experiments were conducted to explore the effects and mechanisms of differentially expressed miRNAs in SLE patients on the differentiation and maturation of monocyte-derived dendritic cells.

RESULTS

Bioinformatics analysis showed that miR-564 was up-regulated in SLE patients, and TP53 was the core target gene of miR-564. The expression level of miR-564 showed a rising trend during the differentiation and maturation of monocytes into Mo-DC cells. The differentiation, maturation and proliferation of Mo-DC cells were significantly inhibited by transfection with miR-564 antagomir. The expression of TP53 is negatively regulated by miR-564. In rescue experiments, the proliferation and migration of DC cells were significantly restored by co-transfection of miR-564 antagomir and TP53 si-RNA.

CONCLUSION

Highly expressed miR-564 promotes the maturation, proliferation of Mo-DC cells by negatively regulating the expression of TP53.

Regulatory Dendritic Cells, T Cell Tolerance, and Dendritic Cell Therapy for Immunologic Disease

Dendritic cells (DC) are antigen-presenting cells that can communicate with T cells both directly and indirectly, regulating our adaptive immune responses against environmental and self-antigens. Under some microenvironmental conditions DC develop into anti-inflammatory cells which can induce immunologic tolerance. A substantial body of literature has confirmed that in such settings regulatory DC (DCreg) induce T cell tolerance by suppression of effector T cells as well as by induction of regulatory T cells (Treg). Many in vitro studies have been undertaken with human DCreg which, as a surrogate marker of antigen-specific tolerogenic potential, only poorly activate allogeneic T cell responses. Fewer studies have addressed the abilities of, or mechanisms by which these human DCreg suppress autologous effector T cell responses and induce infectious tolerance-promoting Treg responses. Moreover, the agents and properties that render DC as tolerogenic are many and varied, as are the cells’ relative regulatory activities and mechanisms of action. Herein we review the most current human and, where gaps exist, murine DCreg literature that addresses the cellular and molecular biology of these cells. We also address the clinical relevance of human DCreg, highlighting the outcomes of pre-clinical mouse and non-human primate studies and early phase clinical trials that have been undertaken, as well as the impact of innate immune receptors and symbiotic microbial signaling on the immunobiology of DCreg.

Novel cell-based therapies in inflammatory bowel diseases: the established concept, promising results

Inflammatory bowel diseases (IBDs) are chronic and relapsing disorders that affect the quality of life in many individuals around the world. Over the past few years, the prevalence of IBDs is substantially rising which might pose a considerable social and economic burden on health systems. Progresses in the management of chronic inflammatory diseases lead to prolonged remission phase and decreased hospitalization rate. However, during treatment, many patients become refractory to conventional therapies. Recently, advanced approaches using somatic cell therapy medicinal products (SCTMPs) including immune and stem cell-based therapies have drawn many researchers' attentions. Promising results from recent trials, alongside with the emerging market indicated that these therapeutic approaches could be an alternative and promising treatment to conventional therapies. In this review, we will discuss recent advances in cell-based therapies, which have been developed for treatment of IBDs. In addition, the global emerging market and the novel products in this field are highlighted.

Tolerogenic Dendritic Cells: The Pearl of Immunotherapy in Organ Transplantation

Over a half century, organ transplantation has become an effective method for the treatment of end-stage visceral diseases. Although the application of immunosuppressants (IS) minimizes the rate of allograft rejection, the common use of IS bring many adverse effects to transplant patients. Moreover, true transplant tolerance is very rare in clinical practice. Dendritic cells (DCs) are thought to be the most potent antigen-presenting cells, which makes a bridge between innate and adaptive immunity. Among their subsets, a small portion of DCs with immunoregulatory function was known as tolerogenic DC (Tol-DC). Previous reports demonstrated the ability of adoptively transferred Tol-DC to approach transplant tolerance in animal models. In this study, we summarized the properties, ex vivo generation, metabolism, and clinical attempts of Tol-DC. Tol-DC is expected to become a substitute for IS to enable patients to achieve immune tolerance in the future.

A Clinical Approach for the Use of VIP Axis in Inflammatory and Autoimmune Diseases

The neuroendocrine and immune systems are coordinated to maintain the homeostasis of the organism, generating bidirectional communication through shared mediators and receptors. Vasoactive intestinal peptide (VIP) is the paradigm of an endogenous neuropeptide produced by neurons and endocrine and immune cells, involved in the control of both innate and adaptive immune responses. Exogenous administration of VIP exerts therapeutic effects in models of autoimmune/inflammatory diseases mediated by G-protein-coupled receptors (VPAC1 and VPAC2). Currently, there are no curative therapies for inflammatory and autoimmune diseases, and patients present complex diagnostic, therapeutic, and prognostic problems in daily clinical practice due to their heterogeneous nature. This review focuses on the biology of VIP and VIP receptor signaling, as well as its protective effects as an immunomodulatory factor. Recent progress in improving the stability, selectivity, and effectiveness of VIP/receptors analogues and new routes of administration are highlighted, as well as important advances in their use as biomarkers, contributing to their potential application in precision medicine. On the 50th anniversary of VIP's discovery, this review presents a spectrum of potential clinical benefits applied to inflammatory and autoimmune diseases.