Bone-derived MSCs encapsulated in alginate hydrogel prevent collagen-induced arthritis in mice through the activation of adenosine A2A/2B receptors in tolerogenic dendritic cells

Tolerogenic dendritic cells (tolDCs) facilitate the suppression of autoimmune responses by differentiating regulatory T cells (Treg). The dysfunction of immunotolerance results in the development of autoimmune diseases, such as rheumatoid arthritis (RA). As multipotent progenitor cells, mesenchymal stem cells (MSCs), can regulate dendritic cells (DCs) to restore their immunosuppressive function and prevent disease development. However, the underlying mechanisms of MSCs in regulating DCs still need to be better defined. Simultaneously, the delivery system for MSCs also influences their function. Herein, MSCs are encapsulated in alginate hydrogel to improve cell survival and retention in situ, maximizing efficacy in vivo. The three-dimensional co-culture of encapsulated MSCs with DCs demonstrates that MSCs can inhibit the maturation of DCs and the secretion of pro-inflammatory cytokines. In the collagen-induced arthritis (CIA) mice model, alginate hydrogel encapsulated MSCs induce a significantly higher expression of CD39+CD73+ on MSCs. These enzymes hydrolyze ATP to adenosine and activate A2A/2B receptors on immature DCs, further promoting the phenotypic transformation of DCs to tolDCs and regulating naïve T cells to Tregs. Therefore, encapsulated MSCs obviously alleviate the inflammatory response and prevent CIA progression. This finding clarifies the mechanism of MSCs-DCs crosstalk in eliciting the immunosuppression effect and provides insights into hydrogel-promoted stem cell therapy for autoimmune diseases.

Expansion of T regulatory lymphocytes by murine bone marrow dendritic cells previously stimulated with Anisakis simplex larval antigens

BACKGROUND Anisakis simplex antigens present immunomodulatory properties by the induction of tolerogenic dendritic cells (DCs) in mice. OBJECTIVES To study the capacity of DCs stimulated with A. simplex excretory-secretory (ES) or crude extract (CE) to generate Tregs. To investigate in vitro effects of antigens on the metabolic activity of splenocytes induced by LPS or CpG. METHODS Phenotypic and functional characterization of T cells co-cultured with A. simplex-pulsed DCs was performed by flow cytometry. Lymphocyte mitochondrial respiratory activity was estimated by the Alamar Blue® Assay. FINDINGS In C57BL/6J, CD4+CD25-Foxp3+ and CD8+CD25-Foxp3+ populations increased by CE-stimulated-DCs. In BALB/c, CE-stimulated-DCs caused the expansion of CD4+CD25+Foxp3+IL-10+ and CD8+CD25+Foxp3+IL-10+. IFN-γ expression raised in BALB/c CD4+CD25+ and CD4+CD25- for CE and ES, respectively. ES-stimulated-DCs increased CD4+CD25+ Foxp3+ and CD8+CD25- Foxp3+ expression in T cells. The association of ES or CE with LPS produced the increase in splenocyte activity in C57BL/6J. The association of CE with CpG decreased the proliferation caused by CpG in C57BL/6J. MAIN CONCLUSIONS A. simplex increase the frequency of Tregs, which in turn produce IL-10 and IFN-γ. The host genetic base is essential in the development of anti-Anisakis immune responses (Th2, Th1, Treg).

Advances in research on the effects of tolerance cells on the treatment of autoimmune thyroiditis / 解放军医学杂志

[Abstract] Tolerance is a state in which the human body is less responsive to changes in internal environmental status caused by drugs or other factors. Tolerance is a biological phenomenon, a natural consequence of the action of drugs or chemical factors. Altered organismal tolerance status often leads to the development of multiple autoimmune diseases. Autoimmune thyroiditis (AIT) is a particular type of autoimmune disease, and is exactly the result of an altered immune tolerance of the thyroid gland to a series of "redundant" antigen-antibody binding reactions that produce specific or non-specific inflammation leading to tissue destruction of the thyroid gland. In recent years, a variety of somatic cell therapies have been developed for the purpose of improving the body's tolerance, partially used in the clinical treatment of autoimmune diseases such as systemic lupus erythematosus, multiple sclerosis and Crohn's disease, etc. Such somatic cells that can regulate tolerance are called tolerogenic cells. The present paper will focus mainly on the specific autoimmune diseases such as AIT, discuss the promising therapeutic implications of tolerogenic cells for this group of diseases, and provide a summary of relevant studies. Hopefully, it will provide new research directions for the treatment of the disease.

Isolated culture and functional identification of mouse bone marrow derived tolerogenic dendritic cells / 中国免疫学杂志

Objective:To establish the methods of isolated culture and functional identification of mice bone marrow derived tolerogenic dendritic cells (CD11b+F4/80 +TDCs) in vitro.Methods: Mice bone marrow cells were isolated and cultured to obtain iDCs with the simulation of mouse rmGM-CSF and rmIL-4.CD11b+F4/80 +TDCs were purified by fluorescence-activated cell sorting on day 6.The morphological changes of TDCs were observed with the inverted microscope dynamically .The expression of CD11b+F4/80 +TDCs were analyzed by the flow cytometry .Tolerogenic function of CD11b+F4/80 +TDCs was evaluated by the expression of MHCⅡ, CD83, IDO, TLR-2, IL-10 and TGF-β1.The expression of MHCⅡ was analyzed by the flow cytometry , and the expression of CD83, IDO and TLR-2 were analyzed by immune-histochemistry.The levels of IL-10 and TGF-β1 in the supernatant of CD11b+F4/80 +TDC were analyzed by ELISA .Meanwhile mature DCs ( mDCs) induced by LPS were used as control .Results:The fresh isolated bone marrow cells look like round and small under microscope .After two days of culture , cells became big and formed into clusters . Five or six days later, cells clusters increased, and the morphology of cells became irregular .At the same time, more dendrite ap-peared on the surface of cells .The percentage of CD11b+F4/80 +TDCs induced by rmGM-CSF and rmIL-4 was about 23%, and the purity of the purified BM CD11b+F4/80 +iDC was about 99%.Compared with mDCs, CD11b+F4/80 +TDCs expressed low levels of MHCⅡand CD83 and high levels of IDO, TLR-2, IL-10 and TGF-β1.Conclusion:CD11b+F4/80 +TDCs derived from mouse bone marrow could be induced successfully by rmGM-CSF and rmIL-4 in vitro.CD11b+F4/80 +TDCs showed tolerogenic function by the expressions of IL-10, TGF-β1, IDO and TLR-2.