Generation and clinical potential of functional T lymphocytes from gene-edited pluripotent stem cells

Optimizing CAR-T cell Culture: Differential effects of IL-2, IL-12, and IL-21 on CAR-T cells

BACKGROUND

Chimeric antigen receptor (CAR)-T therapy has demonstrated sustained clinical remission in numerous hematologic malignancies and has expanded to encompass solid tumors and autoimmune diseases. While progress is being made in establishing optimal culture conditions for CAR-T cells, the identification of the most effective cytokine for promoting their persistence in vitro remains elusive.

METHODS

Here, we employed scRNA-seq (single-cell RNA sequencing) analysis to investigate the potential alterations in biological processes within CAR-T cells following exposure to cytokines (IL-2, IL-12, and IL-21) and antigens. Transcriptomic changes in diverse CAR-T groups were compared following various treatments, with a focus on epigenetic modifications, metabolic shifts, cellular senescence, and exhaustion.

RESULTS

Our study reveals that CAR-T cells treated with antigen, IL-2, and IL-12 exhibit signs of exhaustion and senescence, whereas those treated with IL-21 do not display these characteristics. The activities of glycolysis and epigenetic changes were significantly increased by treatments with antigens, IL-2, and IL-12, while IL-21 treatment maintained the oxidative phosphorylation (OXPHOS) of CAR-T cells.

CONCLUSIONS

Our findings suggest that IL-21 may play a role in preventing senescence and could be utilized in combination with other strategies, such as IL-2 and IL-12, for CAR-T culture.

Dysregulated T-cell homeostasis and decreased CD30+ Treg proliferating in aplastic anemia

Aplastic anemia (AA) is an autoimmune hematopoietic disease mediated by autoreactive T cells leading to bone marrow failure. However, the precise role of autoreactive T cells in the development of AA is not fully understood, hindering the advancement of therapeutic and diagnostic strategies. In this study, we conducted a single-cell transcriptome analysis of CD8+ T cells, conventional CD4+ T (CD4+ Tconv) cells, and Treg cells, to elucidate the potential disruption of T cell homeostasis in patients with AA. We identified changes in CD4+ Tconv cells, including loss of homeostasis in naïve and memory cells and increased differentiation potential in T helper type 1 (TH1), T helper type 2 (TH2), and T helper type 17 (TH17) cells. Additionally, we identified naïve and memory CD8+ T cells that were enforced into an effector state. CD127 is an ideal surface marker for assessing the immune state of CD8+ T cells，as identified by flow cytometry. Abnormal expression of TNFSF8 has been observed in AA and other autoimmune diseases. Flow cytometry analysis revealed that TNFRSF8 (CD30), a receptor for TNFSF8, was predominantly present in human Treg cells. Importantly, patients with AA have a decreased CD30+ Treg subset. RNA-sequencing analysis revealed, that the CD30+ Treg cells are characterized by high proliferation and a remarkable immunosuppressive phenotype. Taken, together, we propose that abnormal TNFSF8/TNFRSF8 signaling is involved in dysfunctional T cell immunity by increasing the destruction of CD30+ Treg cells.

Multi-omics analysis reveals a feedback loop amplifying immune responses in acute graft-versus-host disease due to imbalanced gut microbiota and bile acid metabolism

Acute graft-versus-host disease (aGVHD) is primarily driven by allogeneic donor T cells associated with an altered composition of the host gut microbiome and its metabolites. The severity of aGVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is not solely determined by the host and donor characteristics; however, the underlying mechanisms remain unclear. Using single-cell RNA sequencing, we decoded the immune cell atlas of 12 patients who underwent allo-HSCT: six with aGVHD and six with non-aGVHD. We performed a fecal microbiota (16SrRNA sequencing) analysis to investigate the fecal bacterial composition of 82 patients: 30 with aGVHD and 52 with non-aGVHD. Fecal samples from these patients were analyzed for bile acid metabolism. Through multi-omic analysis, we identified a feedback loop involving "immune cell-gut microbes-bile acid metabolites" contributing to heightened immune responses in patients with aGVHD. The dysbiosis of the gut microbiota and disruption of bile acid metabolism contributed to an exaggerated interleukin-1 mediated immune response. Our findings suggest that resistin and defensins are crucial in mitigating against aGVHD. Therefore, a comprehensive multi-omic atlas incorporating immune cells, gut microbes, and bile acid metabolites was developed in this study and used to propose novel, non-immunosuppressive approaches to prevent aGVHD.

Induced pluripotent stem cells (iPSCs): molecular mechanisms of induction and applications

The induced pluripotent stem cell (iPSC) technology has transformed in vitro research and holds great promise to advance regenerative medicine. iPSCs have the capacity for an almost unlimited expansion, are amenable to genetic engineering, and can be differentiated into most somatic cell types. iPSCs have been widely applied to model human development and diseases, perform drug screening, and develop cell therapies. In this review, we outline key developments in the iPSC field and highlight the immense versatility of the iPSC technology for in vitro modeling and therapeutic applications. We begin by discussing the pivotal discoveries that revealed the potential of a somatic cell nucleus for reprogramming and led to successful generation of iPSCs. We consider the molecular mechanisms and dynamics of somatic cell reprogramming as well as the numerous methods available to induce pluripotency. Subsequently, we discuss various iPSC-based cellular models, from mono-cultures of a single cell type to complex three-dimensional organoids, and how these models can be applied to elucidate the mechanisms of human development and diseases. We use examples of neurological disorders, coronavirus disease 2019 (COVID-19), and cancer to highlight the diversity of disease-specific phenotypes that can be modeled using iPSC-derived cells. We also consider how iPSC-derived cellular models can be used in high-throughput drug screening and drug toxicity studies. Finally, we discuss the process of developing autologous and allogeneic iPSC-based cell therapies and their potential to alleviate human diseases.

Advancements in γδT cell engineering: paving the way for enhanced cancer immunotherapy

Comprising only 1-10% of the circulating T cell population, γδT cells play a pivotal role in cancer immunotherapy due to their unique amalgamation of innate and adaptive immune features. These cells can secrete cytokines, including interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), and can directly eliminate tumor cells through mechanisms like Fas/FasL and antibody-dependent cell-mediated cytotoxicity (ADCC). Unlike conventional αβT cells, γδT cells can target a wide variety of cancer cells independently of major histocompatibility complex (MHC) presentation and function as antigen-presenting cells (APCs). Their ability of recognizing antigens in a non-MHC restricted manner makes them an ideal candidate for allogeneic immunotherapy. Additionally, γδT cells exhibit specific tissue tropism, and rapid responsiveness upon reaching cellular targets, indicating a high level of cellular precision and adaptability. Despite these capabilities, the therapeutic potential of γδT cells has been hindered by some limitations, including their restricted abundance, unsatisfactory expansion, limited persistence, and complex biology and plasticity. To address these issues, gene-engineering strategies like the use of chimeric antigen receptor (CAR) T therapy, T cell receptor (TCR) gene transfer, and the combination with γδT cell engagers are being explored. This review will outline the progress in various engineering strategies, discuss their implications and challenges that lie ahead, and the future directions for engineered γδT cells in both monotherapy and combination immunotherapy.

Challenges and strategies associated with CAR-T cell therapy in blood malignancies

Cellular immunotherapy, particularly CAR-T cells, has shown potential in the improvement of outcomes in patients with refractory and recurrent malignancies of the blood. However, achieving sustainable long-term complete remission for blood cancer remains a challenge, with resistance and relapse being expected outcomes for many patients. Although many studies have attempted to clarify the mechanisms of CAR-T cell therapy failure, the mechanism remains unclear. In this article, we discuss and describe the current state of knowledge regarding these factors, which include elements that influence the CAR-T cell, cancer cells as a whole, and the microenvironment surrounding the tumor. In addition, we propose prospective approaches to overcome these obstacles in an effort to decrease recurrence rates and extend patient survival subsequent to CAR-T cell therapy.

Targeted single-cell RNA sequencing analysis reveals metabolic reprogramming and the ferroptosis-resistant state in hematologic malignancies

Hematologic malignancies are the most common hematopoietic diseases and a major public health concern. However, the mechanisms underlying myeloid tumors remain unknown owing to the intricate interplay between mutations and diverse clonal evolution patterns, as evidenced by the analysis of bulk cell-derived omics data. Several single-cell omics techniques have been used to characterize the hierarchies and altered immune microenvironments of hematologic malignancies. The comprehensive single-cell atlas of hematologic malignancies provides novel opportunities for personalized combinatorial targeted treatments, avoiding unwanted chemo-toxicity. In the present study, we performed transcriptome sequencing by combining single-cell RNA sequencing (scRNA-seq) with a targeted oncogenic gene panel for acute myeloid leukemia, overcoming the limitations of scRNA-seq in detecting oncogenic mutations. The distribution of oncogenic IDH1, IDH2, and KRAS mutations in each cell type was identified in the bone marrow (BM) samples of each patient. Our findings suggest that ferroptosis and metabolic reprogramming are involved in the tumorigenesis and chemotherapy resistance of oncogenic mutation-carrying cells. Biological progression via IDH1, IDH2, and KRAS mutations arrests hematopoietic maturation. Our study findings provide a rationale for using primary BM cells for personalized treatment in clinical settings.

Personalized cancer avatars for patients with thymic malignancies: A pilot study with circulating tumor cell-derived organoids

BACKGROUND

Systemic therapy is the primary treatment for advanced thymic malignancies. However, there is an urgent need to improve clinical outcome. Personalized treatment based on predictive biomarkers is a potential approach to address this requirement. In this study, we aimed to show the correlation between drug sensitivity tests on CTCs-derived organoids and clinical response in patients with thymic malignancies. This approach carries the potential to create personalized cancer avatars and improve treatment outcome for patients.

METHODS

We previously reported potential treatment outcome prediction with patient-derived organoids (cancer avatars) in patients with pancreatic ductal adenocarcinoma. To further investigate the feasibility of this approach in advanced thymic malignancies, we conducted a study in which 12 patients were enrolled and 21 liquid biopsies were performed.

RESULTS

Cancer avatars were successfully derived in 16 out of 21 samples (success rate 76.2%). We found a sensitivity of 1.0 and specificity of 0.6 for drug sensitivity tests on the cancer avatars, and a two-tailed Fisher's exact test revealed a significant correlation between drug sensitivity tests and clinical responses (p = 0.0275).

CONCLUSION

This study supports the potential of circulating tumor cell-derived organoids to inform personalized treatment for advanced thymic malignancies. Further validation of this proof of concept finding is ongoing.

CCL17 acts as an antitumor chemokine in micromilieu‐driven immune skewing

BACKGROUND

Chemokines are critical players in the local immune responses to tumors. CCL17 (thymus and activation-regulated chemokine, TARC) and CCL22 (macrophage-derived chemokine, MDC) can attract CCR4-bearing cells involving the immune landscape of cancer. However, their direct roles and functional states in tumors remain largely unclear.

METHODS

We analyzed the lymphoma-related scRNA-seq and bulk RNA-seq datasets and identified the CCL17/CCL22-CCR4 axis as the unique participant of the tumor microenvironment. Then we edited the A20 lymphoma cell line to express CCL17 and CCL22 and assessed their function using three mouse models (Balb/C mouse, Nude mouse, and NSG mouse). In addition, we retrospectively checked the relationship between the CCL17/CCL22-CCR4 axis and the survival rates of cancer patients.

RESULTS

The active CCL17/CCL22-CCR4 axis is a distinctive feature of the Hodgkin lymphoma microenvironment. CCR4 is widely expressed in immune cells but highly exists on the surface of NK, NKT, and Treg cells. The tumor model of Balb/C mice showed that CCL17 acts as an anti-tumor chemokine mediated by activated T cell response. In addition, the tumor model of Nude mice showed that CCL17 recruits NK cells for inhibiting lymphoma growth and enhances the NK-cDC1 interaction for resisting IL4i1-mediated immunosuppression. Interestingly, CCL17-mediated antitumor immune responses depend on lymphoid lineages but not mainly myeloid ones. Furthermore, we found CCL17/CCL22-CCR4 axis cannot be regarded as biomarkers of poor prognosis in most cancer types from the TCGA database.

CONCLUSION

We provided direct evidence of antitumor functions of CCL17 mediated by the recruitment of conventional T cells, NKT cells, and NK cells. Clinical survival outcomes of target gene (CCL17, CCL22, and CCR4) expression also identified that CCL17/CCL22-CCR4 axis is not a marker of poor prognosis.

Sinomenine promotes differentiation of induced pluripotent stem cells into immature dendritic cells with high induction of immune tolerance

BACKGROUND

Immature dendritic cells (imDCs) play an important role in the induction of donor-specific transplant immunotolerance. However, these cells have limitations, such as rapid maturation and a short lifespan in vivo. In previous studies, induced pluripotent stem cells (iPSCs) differentiated into imDCs, and sinomenine (SN) was used to inhibit the maturation of imDCs.

AIM

To study the capacity of SN to maintain iPSC-derived imDCs (SN-iPSCs-imDCs) in an immature state and the mechanism by which SN-iPSCs-imDCs induce immunotolerance.

METHODS

In this study, mouse iPSCs were induced to differentiate into imDCs in culture medium without or with SN (iPSCs-imDCs and SN-iPSCs-imDCs). The imDC-related surface markers, endocytotic capacity of fluorescein isothiocyanate-Dextran and apoptosis were analyzed by flow cytometry. The effects of iPSCs-imDCs and SN-iPSCs-imDCs on T-cell stimulatory function, and regulatory T (Treg) cell proliferative function in vitro were analyzed by mixed lymphocyte reaction. Cytokine expression was detected by ELISA. The apoptosis-related proteins of iPSCs-DCs and SN-iPSCs-DCs were analyzed by western blotting. The induced immunotolerance of SN-iPSCs-DCs was evaluated by treating recipient Balb/c skin graft mice. Statistical evaluation of graft survival was performed using Kaplan–Meier curves.

RESULTS

Both iPSCs-imDCs and SN-iPSCs-imDCs were successfully obtained, and their biological characteristics and ability to induce immunotolerance were compared. SN-iPSCs-imDCs exhibited higher CD11c levels and lower CD80 and CD86 levels compared with iPSCs-imDCs. Reduced major histocompatibility complex II expression, worse T-cell stimulatory function, higher Treg cell proliferative function and stronger endocytotic capacity were observed with SN-iPSCs-imDCs (P < 0.05). The levels of interleukin (IL)-2, IL-12, interferon-γ in SN-iPSCs-imDCs were lower than those in iPSCs-imDCs, whereas IL-10 and transforming growth factor-β levels were higher (P < 0.05). The apoptosis rate of these cells was significantly higher (P < 0.05), and the expression levels of cleaved caspase3, Bax and cleaved poly(ADP-ribose) polymerase were higher after treatment with lipopolysaccharides, but Bcl-2 was reduced. In Balb/c mice recipients immunized with iPSCs-imDCs or SN-iPSCs-imDCs 7 d before skin grafting, the SN-iPSCs-imDCs group showed lower ability to inhibit donor-specific CD4⁺ T-cell proliferation (P < 0.05) and a higher capacity to induce CD4⁺CD25⁺FoxP3⁺ Treg cell proliferation in the spleen (P < 0.05). The survival span of C57bl/6 skin grafts was significantly prolonged in immunized Balb/c recipients with a donor-specific pattern.

CONCLUSION

This study demonstrated that SN-iPSCs-imDCs have potential applications in vitro and in vivo for induction of immunotolerance following organ transplantation.