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Introduction Erythropoietin (EPO) is a glycoprotein hormone that serves as a primary regulator of differentiation, proliferation, and survival of erythroid progenitor cells (1, 2). In adulthood, EPO is mainly produced [...], Erythropoiesis, the production of red blood cells, must be tightly controlled to ensure adequate oxygen delivery to tissues without causing thrombosis or stroke. Control of physiologic and pathologic erythropoiesis is dependent predominantly on erythropoietin (EPO), the expression of which is regulated by hypoxia-inducible factor (HIF) activity in response to low oxygen tension. Accumulating evidence indicates that oxygen-independent mediators, including inflammatory stimuli, cytokines, and growth factors, also upregulate HIF activity, but it is unclear whether these signals also result in EPO production and erythropoiesis in vivo. Here, we found that signaling through herpesvirus entry mediator (HVEM), a molecule of the TNF receptor superfamily, promoted HIF-1α activity in the kidney and subsequently facilitated renal Epo production and erythropoiesis in vivo under normoxic conditions. This Epo upregulation was mediated by increased production of NO by renal macrophages. Hvem-deficient mice displayed impaired Epo expression and aggravated anemia in response to erythropoietic stress. These data reveal that HVEM signaling functions to promote HIF-1α activity and Epo production, and thus to regulate erythropoiesis. Furthermore, our findings suggest that this molecular mechanism could represent a therapeutic target for Epo-responsive diseases, including anemia. more...

Chimeric antigen receptor‐engineered T (CAR‐T)‐cell therapy holds significant promise for the treatment of hematological malignancies, especially for B‐cell leukemia and lymphoma. However, its efficacy against non‐hematological malignancies has been limited as a result of several biological problems characteristic of the tumor microenvironment of solid tumors. One of the main hurdles is the heterogeneous nature of tumor‐associated antigens (TAA) expressed in solid tumors. Another hurdle is the inefficient activation and limited persistence of CAR‐T cells, mainly as a result of T‐cell exhaustion caused by immunosuppressive factors in the tumor microenvironment. In the present study, to address these problems, we engineered CAR‐T cells to produce antagonistic anti‐programmed cell death protein 1 (PD‐1) single‐chain variable fragment (scFv), by which PD‐1‐dependent inhibitory signals in CAR‐T cells and adjacent tumor‐specific non‐CAR‐T cells are attenuated. In mouse solid tumor models, PD‐1 scFv‐producing CAR‐T cells induced potent therapeutic effects superior to those of conventional CAR‐T cells, along with a significant reduction of apoptotic cell death not only in CAR‐T cells themselves but also in TAA‐specific T cells in the tumor tissue. In addition, the treatment with anti‐PD‐1 scFv‐producing CAR‐T cells resulted in an increased concentration of PD‐1 scFv in tumor tissue but not in sera, suggesting an induction of less severe systemic immune‐related adverse events. Hence, the present study developed anti‐PD‐1 scFv‐producing CAR‐T cell technology and explored its cellular mechanisms underlying potent antitumor efficacy. [ABSTRACT FROM AUTHOR] more...

Interactions between natural killer (NK) cells and dendritic cells (DC) affect maturation and function of both cell populations, including NK cell killing of DC (editing), which is important for controlling the quality of immune responses. We also know that antigen-stimulated Vγ2Vδ2 T cells co-stimulate NK cells via 4-1BB to enhance the killing of tumour cell lines but we do not know what regulates 4-1BB expression or whether other NK effector functions including DC killing, might also be influenced by NK-γδ T-cell cross-talk. Here we show that antigen-stimulated γδ T cells co-stimulate NK cells through inducible T-cell co-stimulator (ICOS)- ICOS ligand (ICOSL) and this signal increases NK cell killing of autologous DC. Effects of NK-γδ T-cell co-culture, which could be reproduced with soluble ICOS-Fc fusion protein, included increased CD69 and 4-1BB expression, interferon-γ, tumour necrosis factor-α, macrophage inflammatory protein-1β, I-309, RANTES and sFas ligand production, as well as elevated mRNA levels for co-stimulatory receptors OX40 (TNFRSF4) and GITR (TNFRSF18). Hence, ICOS-ICOSL co-stimulation of NK by Vγ2Vδ2 T cells had broad effects on NK phenotype and effector functions. The NK-γδ T-cell cross-talk links innate and antigen-specific lymphocyte responses in the control of cytotoxic effector function and DC killing. [ABSTRACT FROM AUTHOR] more...

Cancer immunotherapy using immune checkpoint inhibitors and its combination with other anticancer therapies has emerged as a new standard of care because of the encouraging therapeutic effects in various solid cancers. Nonetheless, glioblastoma and pancreatic cancer remain resistant to immunotherapy and represent intractable cancers with the poorest prognosis. We investigated the therapeutic effects of next-generation chimeric antigen receptor (CAR) T cells producing IL7 and chemokine (C-C motif) ligand 19 (CCL19; referred to as 7 × 19 CAR-T) in these intractable cancers. Cytotoxic activities and therapeutic effects of 7 × 19 CAR-T were evaluated in vitro and in vivo, in a model using EGFR variant III (EGFRvIII)-positive glioblastoma and anti-EGFRvIII CAR-T generated from healthy donor peripheral blood mononuclear cells (PBMC), or a model using HER2-positive pancreatic cancer organoids and anti-HER2 CAR-T generated from the same patient's PBMC. Anti-EGFRvIII 7 × 19 CAR-T exhibited cytotoxic activity specific to EGFRvIII-positive tumor, induced complete rejection of glioblastoma with massive T-cell infiltration and tumor cell death in the tumor tissues, and consequently prolonged mouse survival. Anti-HER2 7 × 19 CAR-T demonstrated a potent cytotoxic activity against autologous HER2-positive pancreatic cancer organoids and induced complete rejection of autologous tumor along with prolonged mouse survival. Our results suggest that 7 × 19 CAR-T could become a therapeutic option for glioblastoma and pancreatic cancer. To the best of our knowledge, this is the first study to demonstrate the therapeutic efficacy of next-generation CAR-T in an autologous model using patient-derived tumor organoids and CAR-T generated from the same patient's PBMC, in which unwanted allogeneic immune responses are fully excluded., Significance: Despite the clinical development of CAR T-cell therapy, its efficacy in solid cancers has yet to be established. This study explored the therapeutic potential and immunologic mechanisms of IL7/CCL19-producing CAR-T therapy in preclinical solid cancer models of glioblastoma and pancreatic cancer. We found that IL7/CCL19-producing CAR-T cells generated from the patient's PBMC showed potent therapeutic effects against the solid cancer model established by inoculating organoids from the autologous tumor tissue., (©2024 The Authors; Published by the American Association for Cancer Research.) more...

Chimeric antigen receptor (CAR)-T cell therapy, where patients' own T cells are engi- neered to express receptor that targets antigen found on the surface of cancer cells, delivers outstanding efficacy to treat hematological malignancies. This personalized medicine has been actively explored by researchers in academia and quickly developed for clinical applica- tion by several pharmaceutical/biotech companies. While CAR-T cell therapy is a highly promising technology, many challenges remain to be overcome in targeting solid tumors, in- cluding on-target off-tumor toxicity, inefficient accumulation and survival of CAR-T cells in the immunosuppressive tumor microenvironment. In this review, we briefly describe the cur- rent status, challenges, and future perspectives of CAR-T cell therapy. more...