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The bone marrow microenvironment of acute myeloid leukemia (AML) characterized by immunosuppressive features fosters leukemia immune escape. Elucidating the immunosuppressive mechanism and developing effective immunotherapeutic strategies are necessary. Here, we found that the Th1% and IFN-γ level were downregulated in bone marrow of AML and NLRP3-activated BMDCs promoted CD4+ T cell differentiation into Th1 cells via IL-1β secretion. However, IFN-γ-producing Th1 cells were not induced by NLRP3-activated BMDCs in the presence of the NLRP3 inflammasome inhibitor MCC950 or anti-IL-1β antibody in vitro unless exogenous IL-1β was replenished. This inhibitory effect on Th1 differentiation was also observed in Nlrp3-/- mice or anti-IL-1β antibody-treated mice. Notably, elevated Th1 cell levels promoted apoptosis and inhibited proliferation in leukemia cells via IFN-γ secretion in vitro and in vivo. Thus, NLRP3-activated BMDCs promote the proliferation of IFN-γ-producing Th1 cells with antileukemic effects and may provide insight into the basis for leukemia immunotherapy in patients with AML. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • MLT alleviated DSS-induced colitis in mice through its regulation of the immune response in BMDCs. • MLT inhibited phagocytosis, migration, and proinflammatory cytokine production of BMDCs from the colitis mice. • MLT promoted the transformation of BMDCs into immune tolerant phenotypes in colitis through affecting ncRNAs. • lncRNA_ENSMUST00000226323, circRNA-0520, and circRNA-2243 were predicted to interact with miR-709. • Ywhaz and CCL19 were the targets of miR-709 and involved in altered PI3K-Akt pathway in colitis. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are key regulators of immunogenic and tolerogenic immune responses. Both these immune responses require DCs respectively to activate effector T cells or to induce their anergy and T regulatory activity. Modifications of DCs in the laboratory and several pharmacological agents can enhance and stabilize their tolerogenic properties. Recent evidences demonstrate that activation of specific toll-like receptors (TLRs) can be involved in induction of DCs with tolerogenic properties able to initiate T regulatory cell responses.In the present chapter, we show a detail protocol to obtain in vitro regulatory conventional DCs (cDCs) in response to repeated exposure to lipopolysaccharide (LPS), a ligand of TLR4, by mimicking the mechanism of endotoxin tolerance. Subsequently, the protective effect of cDCs' conditionate with LPS will be describe in in vivo inflammatory model of endotoxemia. Finally, we illustrate the method to study the ability of LPS-conditionate cDCs to promote T regulatory cells in ex vivo system., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)