Search

Aplastic anemia (AA) is a bone marrow (BM) failure syndrome mediated by hyperactivated T‐cells with heterogeneous pathogenic factors. The onset of BM failure cannot be accurately determined in humans; therefore, exact pathogenesis remains unclear. In this study, a cellular atlas and microenvironment interactions is established using unbiased single‐cell RNA‐seq, along with multi‐omics analyses (mass cytometry, cytokine profiling, and oxidized fatty acid metabolomics). A new KIR+CD8+ regulatory T cells (Treg) subset is identified in patients with AA that engages in immune homeostasis. Conventional CD4+ T‐cells differentiate into highly differentiated T helper cells with type 2 cytokines (IL‐4, IL‐6, and IL‐13), GM‐SCF, and IL‐1β. Immunosuppressive homeostasis is impaired by enhanced apoptosis of activated Treg cells. Pathological Vδ1 cells dominated the main fraction of γδ T‐cells. The B/plasma, erythroid, and myeloid lineages also exhibit substantial pathological features. Interactions between TNFSF12‐TNFRSF12A, TNF‐TNFRSF1A, and granzyme‐gasdermin are associated with the cell death of hematopoietic stem/progenitor (HSPCs), Treg, and early erythroid cells. Ferroptosis, a major driver of HSPCs destruction, is identified in patients with AA. Furthermore, a case of twins with AA is reported to enhance the persuasiveness of the analysis. These results collectively constitute the cellular atlas and microenvironment interactions in patients with AA and provide novel insights into the development of new therapeutic opportunities. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) are a large family of proteins that are expressed in immune cells and various tumor cells. TLR7/8 are located in the intracellular endosomes, participate in tumor immune surveillance and play different roles in tumor growth. Activation of TLRs 7 and 8 triggers induction of a Th1 type innate immune response in the highly sophisticated process of innate immunity signaling with the recent research advances involving the small molecule activation of TLR 7 and 8. The wide range of expression and clinical significance of TLR7/TLR8 in different kinds of cancers have been extensively explored. TLR7/TLR8 can be used as novel diagnostic biomarkers, progression and prognostic indicators, and immunotherapeutic targets for various tumors. Although the mechanism of action of TLR7/8 in cancer immunotherapy is still incomplete, TLRs on T cells are involved in the regulation of T cell function and serve as co-stimulatory molecules and activate T cell immunity. TLR agonists can activate T cell-mediated antitumor responses with both innate and adaptive immune responses to improve tumor therapy. Recently, novel drugs of TLR7 or TLR8 agonists with different scaffolds have been developed. These agonists lead to the induction of certain cytokines and chemokines that can be applied to the treatment of some diseases and can be used as good adjutants for vaccines. Furthermore, TLR7/8 agonists as potential therapeutics for tumor-targeted immunotherapy have been developed. In this review, we summarize the recent advances in the development of immunotherapy strategies targeting TLR7/8 in patients with various cancers and chronic hepatitis B. [ABSTRACT FROM AUTHOR]

Engineered T cells have been shown to be highly effective in cancer immunotherapy, although T cell exhaustion presents a challenge for their long-term function. Additional T-cell sources must be exploited to broaden the application of engineered T cells for immune defense and reconstitution. Unlimited sources of pluripotent stem cells (PSCs) have provided a potential opportunity to generate precise-engineered therapeutic induced T (iT) cells. Single-cell transcriptome analysis of PSC-derived induced hematopoietic stem and progenitor cells (iHSPC)/iT identified the developmental pathways and possibilities of generating functional T cell from PSCs. To date, the PSC-to-iT platforms encounter several problems, including low efficiency of conventional T subset specification, limited functional potential, and restrictions on large-scale application, because of the absence of a thymus-like organized microenvironment. The updated PSC-to-iT platforms, such as the three-dimensional (3D) artificial thymic organoid (ATO) co-culture system and Runx1/Hoxa9-enforced iT lymphopoiesis, provide fresh perspectives for coordinating culture conditions and transcription factors, which may greatly improve the efficiency of T-cell generation greatly. In addition, the improved PSC-to-iT platform coordinating gene editing technologies will provide various functional engineered unconventional or conventional T cells. Furthermore, the clinical applications of PSC-derived immune cells are accelerating from bench to bedside. [ABSTRACT FROM AUTHOR]

MiR-150-5p is an immune-related miRNA and elevated in the plasma of patients with aplastic anemia (AA), but its role in T cell activation in patients with severe aplastic anemia (SAA) is unclear. This study aims to explore the role of miR-150-5p in T cell activation of SAA. RT-PCR and Western blot were used to detect the expression of mRNA and protein. The cell proportion was detected by flow cytometry. The lentiviruses expressing miR-150-5p inhibitor and Bach2 shRNA were respectively infected to produce stable miR-150-5p or Bach2 knockout cells. Brdu incorporation method was used to detect T cell proliferation. SAA mouse model was induced with cyclophosphamide and busulfan, and intravenous injection of LV inhibitor NC and LV-miR-150-5p inhibitor. The miR-150-5p expression is up-regulated in SAA, which is negatively correlated with Bach2. Inhibition of miR-150-5p reduces the activation of T cells. MiR-150-5p directly targeted 3′UTR of Bach2. Moreover, the expression of miR-150-5p and the activation of T cells were decreased in SAA mouse model. MiR-150-5p promotes T cell activation in SAA by targeting Bach2. Targeting miR-150-5p may be a new molecular therapy for SAA patients. [ABSTRACT FROM AUTHOR]

This study was designed to explore whether exosomal sphingosine 1‐phosphate (S1P) from mesenchymal stem cells (MSCs) regulate the Treg/Th17 balance in aplastic anemia (AA) patients and to validate the underlying mechanism. To address this, exosomes from human bone marrow MSCs (MSCs‐Exos) were co‐cultured with CD4+ T cells from AA patients (AA CD4+ T cells), which were transfected with si‐S1PR1, si‐S1PR3, or not. The proportion of Th17 and Treg was evaluated by flow cytometry. The levels of Th17‐associated interleukin‐17 (IL‐17), Treg‐associated IL‐10, and transforming growth factor‐β were determined by ELISA. S1P content in MSCs‐Exos isolated from control, si‐SphK1, or si‐SphK2 transfected MSCs was examined by LC–MS/MS. Hematoxylin and eosin staining of bone marrow tissues was performed to evaluate the effect of MSCs‐Exos in AA mice. Our results showed that MSCs‐Exos reversed the increased Th17/Treg in AA through SphK1‐mediated exosomal S1P enrichment. Furthermore, the promotion of Treg differentiation by exosomal S1P from MSCs was mediated through the receptor S1PR1 expressed on CD4+ T cells. Further in vivo experiments showed that MSCs‐Exos reversed the increased Th17/Treg and alleviated AA progression in AA mice. In summary, SphK1‐mediated enrichment of exosomal S1P secreted by MSCs reversed the increased Treg/Th17 ratio via the receptor S1PR1 in AA patients. © 2019 IUBMB Life, 71(9):1284–1292, 2019 [ABSTRACT FROM AUTHOR]