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Multiple sclerosis (MS) is a chronic disease characterized by dysregulated self-reactive immune responses that damage the neurons' myelin sheath, leading to progressive disability. The primary therapeutic option, immunosuppressants, inhibits pathogenic anti-myelin responses but depresses the immune system. Antigen-specific monocyte-derived autologous tolerogenic dendritic cells (tolDCs) offer alternative therapeutic approaches to restore tolerance to autoantigens without causing generalized immunosuppression. However, immune dysregulation in MS could impact the properties of the monocytes used as starting material for this cell therapy. Here, we characterized CD14+ monocytes, mature dendritic cells, and vitamin D3-tolDCs (VitD3-tolDCs) from active, treatment-naive MS patients and healthy donors (HDs). Using multiomics, we identified a switch in these cell types toward proinflammatory features characterized by alterations in the aryl hydrocarbon receptor (AhR) and NF-κB pathways. MS patient-derived VitD3-tolDCs showed reduced tolerogenic properties compared with those from HDs, which were fully restored through direct AhR agonism and by use of in vivo or in vitro dimethyl fumarate (DMF) supplementation. Additionally, in the experimental autoimmune encephalomyelitis mouse model, combined therapy of DMF and VitD3-tolDCs was more efficient than monotherapies in reducing the clinical score of mice. We propose that a combined therapy with DMF and VitD3-tolDCs offers enhanced therapeutic potential in treating MS.

The active form of vitamin D, 1,25-dihydroxyvitamin D3, induces a stable tolerogenic phenotype in dendritic cells (DCs). This process involves the vitamin D receptor (VDR), which translocates to the nucleus, binds its cognate genomic sites, and promotes epigenetic and transcriptional remodeling. In this study, we report the occurrence of vitamin D-specific DNA demethylation and transcriptional activation at VDR binding sites associated with the acquisition of tolerogenesis in vitro. Differentiation to tolerogenic DCs associates with activation of the IL-6-JAK-STAT3 pathway. We show that JAK2-mediated STAT3 phosphorylation is specific to vitamin D stimulation. VDR and the phosphorylated form of STAT3 interact with each other to form a complex with methylcytosine dioxygenase TET2. Most importantly, pharmacological inhibition of JAK2 reverts vitamin D-induced tolerogenic properties of DCs. This interplay among VDR, STAT3, and TET2 opens up possibilities for modulating DC immunogenic properties in clinics., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Autologous antigen-specific therapies based on tolerogenic dendritic cells (tolDC) offer the possibility to treat autoimmune diseases by restoring homeostasis and targeting specifically autoreactive responses. Here, we explore the hypothesis that systemic inflammation occurring in autoimmune diseases, such as multiple sclerosis (MS), can generate a disease-specific environment able to alter the functionality of tolDC. In this context in fact, a combined therapy of tolDC with an immunomodulatory treatment could potentiate the beneficial effect of this antigen-specific cell therapy. For this purpose, we analyzed the efficacy of a combined therapy based on the use of vitamin D3 (VitD3)-tolDC plus interferon beta (IFN-beta) in MS. VitD3-tolDC were generated from healthy donors and MS patients and co-cultured with allogeneic peripheral blood mononuclear cells, in the presence or absence of IFN-beta. In vitro, VitD3-tolDC treatment reduced the percentage of activated T cells and allogeneic proliferation, whereas VitD3-tolDC+IFN-beta treatment enhanced the suppressive ability of VitD3-tolDC and, additionally, induced a shift towards a Th2 profile. To determine the clinical benefit of the combined therapy, C57BL/6-experimental autoimmune encephalomyelitis (EAE)-induced mice were treated with antigen-specific VitD3-tolDC and/or IFN-beta. Treatment of EAE mice with combined therapy ameliorated the disease course compared to each monotherapy. These results suggest that a combined therapy based on antigen-specific VitD3-tolDC and IFN-beta may represent a promising strategy for MS patients.

The use of autologous tolerogenic dendritic cells (tolDC) has become a promising strategy to re-establish immune tolerance in autoimmune diseases. Among the different strategies available, the use of vitamin D3 for the generation of tolDC (VitD3-tolDC) has been widely tested because of their immune regulatory properties. To identify molecules and pathways involved in the generation of VitD3-tolDC, we established an easy and fast gene silencing method based on the use of Viromer blue to introduce siRNA into monocytes on day 1 of culture differentiation. The analysis of the effect of CD209 (DC-SIGN) and CD115 (CSF1R) down-modulation on the phenotype and functionality of transfected VitD3-tolDC revealed a partial role of CD115 in their tolerogenicity. Further investigations showed that CSF1R-CSF1 signaling is involved in the induction of cell metabolic reprogramming, triggering glycolysis to produce high amounts of lactate, a novel suppressive mechanism of T cell proliferation, recently found in autologous tolerogenic dendritic cells (ATDCs).

Dendritic cells (DCs), the most efficient antigen-presenting cells, are necessary for the effective activation of naïve T cells. DCs can also acquire tolerogenic functions in vivo and in vitro in response to various stimuli, including interleukin (IL)-10, transforming growth factor (TGF)-β, vitamin D3, corticosteroids, and rapamycin. In this review, we provide a wide perspective on the regulatory mechanisms, including crosstalk with other cell types, downstream signaling pathways, transcription factors, and epigenetics, underlying the acquisition of tolerogenesis by DCs, with a special focus on human studies. Finally, we present clinical assays targeting, or based on, tolerogenic DCs in inflammatory diseases. Our discussion provides a useful resource for better understanding the biology of tolerogenic DCs and their manipulation to improve the immunological fitness of patients with certain inflammatory conditions., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In female athletes, the incidence of menstrual disorders is variable, and their impact on perceived stress and quality of life (QoL) is poorly known.The aim of the present study was to investigate the menstrual cycle characteristics and disorders in athletes performing different sports, also evaluating perceived stress and QoL according to their menstrual cycle features. A cross-sectional survey was conducted in nulliparous elite athletes of reproductive age, and the study population included 112 cases. Three questionnaires were administered on (1) gynecological health, (2) perceived stress scale (PSS), and (3) short form QoL (SF-12). A group of women not practising regular sport activities (n = 103) was used as control. Data obtained in elite athletes were also analyzed according to the static and dynamic component percentage of practised sports in 3 sub-groups. Athletes had a significantly higher incidence of irregular periods and heavy menstrual bleeding (HMB) (p < 0.01) and a lower incidence of dysmenorrhea (p < 0.01) than controls. Furthermore, athletes had a better physical QoL (53.9 ± 5.9 vs 51.2 ± 6.0) (p < 0.05) but higher PPS level (17.3 ± 4.8 vs 13.8 ± 4.8) and a worse mental QoL (44.9 ± 9.9 vs 47.6 ± 9.0) (p < 0.05) than controls. HMB was associated with lower mental scores (39.7 ± .8.9 vs 45.6 ± 9.9) and higher PSS scores (19.8 ± .3.2 vs 17.0 ± .4.9) than those observed in athletes with normal bleeding. No difference was found in different sports regarding gynecological health, PSS level, and QoL. An increased incidence of HMB should be considered in elite athletes with increased PSS and impaired QoL.