Regulation of CD8+ T memory and exhaustion by the mTOR signals

PD-1+CD8+ T Cell-Mediated Hepatocyte Pyroptosis Promotes Progression of Murine Autoimmune Liver Disease

The specific mechanisms underlying effector pathways in autoimmune liver disease remain enigmatic and therefore constructing appropriate murine models to investigate disease pathogenesis becomes critical. A spontaneous severe murine model of autoimmune liver disease has been previously established in dnTGFβRII Aire-/- mice, exhibiting disease phenotypes that resemble both human primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). The data suggests that auto-reactive liver-specific CD8+ T cells are the primary pathogenic cells in liver injury. In this study, these data are advanced through the use of both single-cell sequencing and extensive in vitro analysis. The results identify a specific expanded pathogenic subset of PD-1+CD8+ T cells in the liver, exhibiting strong functional activity and cytotoxicity against target cells. Depletion of PD-1+CD8+ T cells using CAR-T cells effectively alleviates the disease. GSDMD-mediated pyroptosis is found to be aberrantly activated in the livers of model mice, and treatment with a GSDMD-specific inhibitor significantly inhibits disease progression. In vitro experiments reveal that PD-1+CD8+ T cells can induce the pyroptosis of hepatocytes through elevated production of granzyme B and perforin-1. These results provide a novel explanation for the cytotoxic activity of pathogenic liver PD-1+CD8+ T cells in autoimmune liver diseases and offer potential therapeutic targets.

Pathway of LCK Tyrosine Kinase and mTOR Signaling in Children with T-Cell Acute Lymphoblastic Leukemia

The aim of this study is to analyze available research on targeting signaling pathways for the development of new drugs in patients with T-cell acute lymphoblastic leukemia (T-ALL). This analysis focuses specifically on the role of LCK tyrosine kinase and mTOR signaling pathways in pediatric patients. Outcome: Current literature suggests that these pathways play a significant role in the regulation of T-cell cycles, making them potential therapeutic targets. However, despite promising findings, there remains a need for further research, particularly in pediatric populations, to fully understand the therapeutic implications and to optimize drug development. The conclusion drawn from this analysis highlights the significant influence of LCK and mTOR on T-cell cycle regulation, underscoring the importance of continued investigation in this area.

Double-Faced Immunological Effects of CDK4/6 Inhibitors on Cancer Treatment: Challenges and Perspectives

Cyclin-dependent kinases (CDKs) are generally involved in the progression of cell cycle and cell division in normal cells, while abnormal activations of CDKs are deemed to be a driving force for accelerating cell proliferation and tumorigenesis. Therefore, CDKs have become ideal therapeutic targets for cancer treatment. The U.S FDA has approved three CDK4/6 inhibitors (CDK4/6is) for the treatment of patients with hormone receptor-positive (HR+) or human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer, and these drugs showed impressive results in clinics. Besides cell-cycle arrest, there is growing evidence that CDK4/6is exert paradoxical roles on cancer treatment by altering the immune system. Indeed, clinical data showed that CDK4/6is could change the immune system to exert antitumor effects, while these changes also caused tumor resistance to CDK4/6i. However, the molecular mechanism for the regulation of the immune system by CDK4/6is is unclear. In this review, we comprehensively discuss the paradoxical immunological effects of CDK4/6is in cancer treatment, elucidating their anticancer mechanisms through immunomodulatory activity and induction of acquired drug resistance by dysregulating the immune microenvironment. More importantly, we suggest a few strategies including combining CDK4/6is with immunotherapy to overcome drug resistance.

Erythropoietin induces tumour progression and CD39 expression on immune cells in a preclinical model of triple-negative breast cancer

The adverse effects observed in some cancer patients treated with erythropoiesis-stimulating agents such as erythropoietin (EPO) might be due to the latter's well-known immunosuppressive functions. Here, we used a mouse model of syngeneic triple-negative breast cancer to explore EPO's immunomodulatory role in a tumour setting. Our results showed that EPO treatment promotes tumour growth, exacerbates the 'immune desert', and results in a 'cold tumour'. EPO treatment changed the immune cell distribution in peripheral blood, secondary lymphoid organs, and the tumour microenvironment (TME). Our in-depth analysis showed that EPO mainly impacts CD4 T cells by accelerating their activation in the spleen and thus their subsequent exhaustion in the TME. This process is accompanied by a general elevation of CD39 expression by several immune cells (notably CD4 T cells in the tumour and spleen), which promotes an immunosuppressive TME. Lastly, we identified a highly immunosuppressive CD39+ regulatory T cell population (ICOS+, CTLA4+, Ki67+) as a potential biomarker of the risk of EPO-induced tumour progression. EPO displays pleiotropic immunosuppressive functions and enhances mammary tumour progression in mice.

Inflammatory tissue priming: novel insights and therapeutic opportunities for inflammatory rheumatic diseases

Due to optimised treatment strategies and the availability of new therapies during the last decades, formerly devastating chronic inflammatory diseases such as rheumatoid arthritis or systemic sclerosis (SSc) have become less menacing. However, in many patients, even state-of-the-art treatment cannot induce remission. Moreover, the risk for flares strongly increases once anti-inflammatory therapy is tapered or withdrawn, suggesting that underlying pathological processes remain active even in the absence of overt inflammation. It has become evident that tissues have the ability to remember past encounters with pathogens, wounds and other irritants, and to react more strongly and/or persistently to the next occurrence. This priming of the tissue bears a paramount role in defence from microbes, but on the other hand drives inflammatory pathologies (the Dr Jekyll and Mr Hyde aspect of tissue adaptation). Emerging evidence suggests that long-lived tissue-resident cells, such as fibroblasts, macrophages, long-lived plasma cells and tissue-resident memory T cells, determine inflammatory tissue priming in an interplay with infiltrating immune cells of lymphoid and myeloid origin, and with systemically acting factors such as cytokines, extracellular vesicles and antibodies. Here, we review the current state of science on inflammatory tissue priming, focusing on tissue-resident and tissue-occupying cells in arthritis and SSc, and reflect on the most promising treatment options targeting the maladapted tissue response during these diseases.

Lysosomes in the immunometabolic reprogramming of immune cells in atherosclerosis

Lysosomes have a central role in the disposal of extracellular and intracellular cargo and also function as metabolic sensors and signalling platforms in the immunometabolic reprogramming of macrophages and other immune cells in atherosclerosis. Lysosomes can rapidly sense the presence of nutrients within immune cells, thereby switching from catabolism of extracellular material to the recycling of intracellular cargo. Such a fine-tuned degradative response supports the generation of metabolic building blocks through effectors such as mTORC1 or TFEB. By coupling nutrients to downstream signalling and metabolism, lysosomes serve as a crucial hub for cellular function in innate and adaptive immune cells. Lysosomal dysfunction is now recognized to be a hallmark of atherogenesis. Perturbations in nutrient-sensing and signalling have profound effects on the capacity of immune cells to handle cholesterol, perform phagocytosis and efferocytosis, and limit the activation of the inflammasome and other inflammatory pathways. Strategies to improve lysosomal function hold promise as novel modulators of the immunoinflammatory response associated with atherosclerosis. In this Review, we describe the crosstalk between lysosomal biology and immune cell function and polarization, with a particular focus on cellular immunometabolic reprogramming in the context of atherosclerosis.

Phenotypic and spatial heterogeneity of CD8+ tumour infiltrating lymphocytes

CD8+ T cells are the workhorses executing adaptive anti-tumour response, and targets of various cancer immunotherapies. Latest advances have unearthed the sheer heterogeneity of CD8+ tumour infiltrating lymphocytes, and made it increasingly clear that the bulk of the endogenous and therapeutically induced tumour-suppressive momentum hinges on a particular selection of CD8+ T cells with advantageous attributes, namely the memory and stem-like exhausted subsets. A scrutiny of the contemporary perception of CD8+ T cells in cancer and the subgroups of interest along with the factors arbitrating their infiltration contextures, presented herein, may serve as the groundwork for future endeavours to probe further into the regulatory networks underlying their differentiation and migration, and optimise T cell-based immunotherapies accordingly.

Teplizumab induces persistent changes in the antigen-specific repertoire in individuals at risk for type 1 diabetes

BACKGROUNDTeplizumab, a non-FcR-binding anti-CD3 mAb, is approved to delay progression of type 1 diabetes (T1D) in at-risk patients. Previous investigations described the immediate effects of the 14-day treatment, but longer-term effects of the drug remain unknown.METHODSWith an extended analysis of study participants, we found that 36% were undiagnosed or remained free of clinical diabetes after 5 years, suggesting operational tolerance. Using single-cell RNA sequencing, we compared the phenotypes, transcriptome, and repertoire of peripheral blood CD8+ T cells including autoreactive T cells from study participants before and after teplizumab and features of responders and non-responders.RESULTSAt 3 months, there were transcriptional signatures of cell activation in CD4+ and CD8+ T cells including signaling that was reversed at 18 months. At that time, there was reduced expression of genes in T cell receptor and activation pathways in clinical responders. In CD8+ T cells, we found increased expression of genes associated with exhaustion and immune regulation with teplizumab treatment. These transcriptional features were further confirmed in an independent cohort. Pseudotime analysis showed differentiation of CD8+ exhausted and memory cells with teplizumab treatment. IL7R expression was reduced, and patients with lower expression of CD127 had longer diabetes-free intervals. In addition, the frequency of autoantigen-reactive CD8+ T cells, which expanded in the placebo group over 18 months, did not increase in the teplizumab group.CONCLUSIONThese findings indicate that teplizumab promotes operational tolerance in T1D, involving activation followed by exhaustion and regulation, and prevents expansion of autoreactive T cells.TRIAL REGISTRATIONClinicalTrials.gov NCT01030861.FUNDINGNational Institute of Diabetes and Digestive and Kidney Diseases/NIH, Juvenile Diabetes Research Foundation.

Cytosolic protein translation regulates cell asymmetry and function in early TCR activation of human CD8+ T lymphocytes

Introduction

CD8+ cytotoxic T lymphocytes (CTLs) are highly effective in defending against viral infections and tumours. They are activated through the recognition of peptide-MHC-I complex by the T-cell receptor (TCR) and co-stimulation. This cognate interaction promotes the organisation of intimate cell-cell connections that involve cytoskeleton rearrangement to enable effector function and clearance of the target cell. This is key for the asymmetric transport and mobilisation of lytic granules to the cell-cell contact, promoting directed secretion of lytic mediators such as granzymes and perforin. Mitochondria play a role in regulating CTL function by controlling processes such as calcium flux, providing the necessary energy through oxidative phosphorylation, and its own protein translation on 70S ribosomes. However, the effect of acute inhibition of cytosolic translation in the rapid response after TCR has not been studied in mature CTLs.

Methods

Here, we investigated the importance of cytosolic protein synthesis in human CTLs after early TCR activation and CD28 co-stimulation for the dynamic reorganisation of the cytoskeleton, mitochondria, and lytic granules through short-term chemical inhibition of 80S ribosomes by cycloheximide and 80S and 70S by puromycin.

Results

We observed that eukaryotic ribosome function is required to allow proper asymmetric reorganisation of the tubulin cytoskeleton and mitochondria and mTOR pathway activation early upon TCR activation in human primary CTLs.

Discussion

Cytosolic protein translation is required to increase glucose metabolism and degranulation capacity upon TCR activation and thus to regulate the full effector function of human CTLs.

Rapamycin circumvents anti PD-1 therapy resistance in colorectal cancer by reducing PD-L1 expression and optimizing the tumor microenvironment

The unresectable or postoperative recurrence of advanced metastatic colorectal cancer (CRC) is the difficulty of its clinical management, and pharmacological therapy is the main source of benefit. Immune checkpoint inhibitors are therapeutic options but are effective in approximately 5 % of patients with deficient mismatch repair (MMR)/microsatellite instability CRC and are ineffective in patients with MMR-proficient (pMMR)/microsatellite stable (MSS) CRCs, which may be associated with the tumor microenvironment (TME). Here, we propose a new combination strategy and evaluate the efficacy of rapamycin (Rapa) combined with anti-PD-1 (αPD-1) in CT26 tumor-bearing mice, azoxymethane (AOM)/dextran sodium sulfate (DSS) inflammation-associated CRC mice, CT26-Luc tumor-bearing mice with postoperative recurrence, and CT26 liver metastasis mice. The results revealed that Rapa improved the therapeutic effect of αPD-1 and effectively inhibited colorectal carcinogenesis, postoperative recurrence, and liver metastasis. Mechanistically, Rapa improved the anticancer effect of αPD-1, associated with Rapa reprograming of the immunosuppressive TME. Rapa effectively depleted α-SMA+ cancer-associated fibroblasts and degraded collagen in the tumor tissue, increasing T lymphocyte infiltration into the tumor tissue. Rapa induced the downregulation of programed cell death 1 ligand 1 (PD-L1) protein and transcript levels in CT26 cells, which may be associated with the inhibition of the mTOR/P70S6K signaling axis. Furthermore, co-culture of tumor cells and CD8+ T lymphocytes demonstrated that Rapa-induced PD-L1 downregulation in tumor cells increased spleen-derived CD8+ T lymphocyte activation. Therefore, Rapa improves the anti-tumor effect of αPD-1 in CRCs, providing new ideas for its use to improve combinatorial strategies for anti-PD-1 immunotherapy.

Metabolic priming of GD2 TRAC-CAR T cells during manufacturing promotes memory phenotypes while enhancing persistence

Manufacturing chimeric antigen receptor (CAR) T cell therapies is complex, with limited understanding of how medium composition impacts T cell phenotypes. CRISPR-Cas9 ribonucleoproteins can precisely insert a CAR sequence while disrupting the endogenous T cell receptor alpha constant (TRAC) gene resulting in TRAC-CAR T cells with an enriched stem cell memory T cell population, a process that could be further optimized through modifications to the medium composition. In this study we generated anti-GD2 TRAC-CAR T cells using "metabolic priming" (MP), where the cells were activated in glucose/glutamine-low medium and then expanded in glucose/glutamine-high medium. T cell products were evaluated using spectral flow cytometry, metabolic assays, cytokine production, cytotoxicity assays in vitro, and potency against human GD2+ xenograft neuroblastoma models in vivo. Compared with standard TRAC-CAR T cells, MP TRAC-CAR T cells showed less glycolysis, higher CCR7/CD62L expression, more bound NAD(P)H activity, and reduced IFN-γ, IL-2, IP-10, IL-1β, IL-17, and TGF-β production at the end of manufacturing ex vivo, with increased central memory CAR T cells and better persistence observed in vivo. MP with medium during CAR T cell biomanufacturing can minimize glycolysis and enrich memory phenotypes ex vivo, which could lead to better responses against solid tumors in vivo.

DEPDC5 protects CD8+ T cells from ferroptosis by limiting mTORC1-mediated purine catabolism

Peripheral CD8+ T cell number is tightly controlled but the precise molecular mechanism regulating this process is still not fully understood. In this study, we found that epilepsy patients with loss of function mutation of DEPDC5 had reduced peripheral CD8+ T cells, and DEPDC5 expression positively correlated with tumor-infiltrating CD8+ T cells as well as overall cancer patient survival, indicating that DEPDC5 may control peripheral CD8+ T cell homeostasis. Significantly, mice with T cell-specific Depdc5 deletion also had reduced peripheral CD8+ T cells and impaired anti-tumor immunity. Mechanistically, Depdc5-deficient CD8+ T cells produced high levels of xanthine oxidase and lipid ROS due to hyper-mTORC1-induced expression of ATF4, leading to spontaneous ferroptosis. Together, our study links DEPDC5-mediated mTORC1 signaling with CD8+ T cell protection from ferroptosis, thereby revealing a novel strategy for enhancing anti-tumor immunity via suppression of ferroptosis.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Metabolic priming of GD2 TRAC -CAR T cells during manufacturing promotes memory phenotypes while enhancing persistence

Manufacturing Chimeric Antigen Receptor (CAR) T cell therapies is complex, with limited understanding of how media composition impact T-cell phenotypes. CRISPR/Cas9 ribonucleoproteins can precisely insert a CAR sequence while disrupting the endogenous T cell receptor alpha constant ( TRAC ) gene resulting in TRAC -CAR T cells with an enriched stem cell memory T-cell population, a process that could be further optimized through modifications to the media composition. In this study we generated anti-GD2 TRAC -CAR T cells using "metabolic priming" (MP), where the cells were activated in glucose/glutamine low media and then expanded in glucose/glutamine high media. T cell products were evaluated using spectral flow cytometry, metabolic assays, cytokine production, cytotoxicity assays in vitro and potency against human GD2+ xenograft neuroblastoma models in vivo . Compared to standard TRAC -CAR T cells, MP TRAC -CAR T cells showed less glycolysis, higher CCR7/CD62L expression, more bound NAD(P)H activity and reduced IFN-γ, IL-2, IP-10, IL-1β, IL-17, and TGFβ production at the end of manufacturing ex vivo , with increased central memory CAR T cells and better persistence observed in vivo . Metabolic priming with media during CAR T cell biomanufacturing can minimize glycolysis and enrich memory phenotypes ex vivo , which could lead to better responses against solid tumors in vivo .

Foxm1-Mediated Transcriptional Inactivation of NLRP3 Inflammasome Promotes Immunosuppression in Cervical Cancer

Foxm1 functions as an oncogene in multiple human malignancies, including cervical cancer. However, the potential of Foxm1 in the tumor microenvironment (TME) is still unknown. The purpose of the present study is to investigate the role of Foxm1 in CD8+ T cell anti-tumor immunity. RT-qPCR is conducted to calculate mRNA levels. JASPAR is used to predict the binding sites between Foxm1 and NLRP3. ChIP assay is performed to verify the occupancy of Foxm1 on the promoter of NLRP3. Modulatory relationship between Foxm1 and NLRP3 is verified by luciferase assay. In vivo assays are conducted to further verify the role of Foxm1/NLRP3 axis in cervical cancer. HE staining assay is applied for histological analysis. Flow cytometry is conducted to determine the functions of immune cells. We found that Foxm1 knockdown decreases tumor burden and suppresses tumor growth of cervical cancer. Foxm1 knock-down promotes the infiltration of CD8+ T cells. Foxm1 deficiency inhibits the exhaustion of CD8+ T cells and facilitates the maintenance of CD8+ effector and stem-like T cells. Moreover, Foxm1 transcriptionally inactivates NLRP3 and suppresses the expression of innate cytokines IL-1β and IL-18. However, inhibition of NLRP3 inflammasome or neutralizing IL-1β and IL-18 inhibits anti-tumor immunity and promoted tumor growth in Foxm1 deficiency in CD8+ T cells. In summary, targeting Foxm1 mediates the activation of NLRP3 inflammasome and stimulates CD8+ T cell anti-tumor immunity in cervical cancer.

Immune Diseases Associated with Aging: Molecular Mechanisms and Treatment Strategies

Aging is associated with a decline in immune function, thereby causing an increased susceptibility to various diseases. Herein, we review immune diseases associated with aging, focusing on tumors, atherosclerosis, and immunodeficiency disorders. The molecular mechanisms underlying these conditions are discussed, highlighting telomere shortening, tissue inflammation, and altered signaling pathways, e.g., the mammalian target of the rapamycin (mTOR) pathway, as key contributors to immune dysfunction. The role of the senescence-associated secretory phenotype in driving chronic tissue inflammation and disruption has been examined. Our review underscores the significance of targeting tissue inflammation and immunomodulation for treating immune disorders. In addition, anti-inflammatory medications, including corticosteroids and nonsteroidal anti-inflammatory drugs, and novel approaches, e.g., probiotics and polyphenols, are discussed. Immunotherapy, particularly immune checkpoint inhibitor therapy and adoptive T-cell therapy, has been explored for its potential to enhance immune responses in older populations. A comprehensive analysis of immune disorders associated with aging and underlying molecular mechanisms provides insights into potential treatment strategies to alleviate the burden of these conditions in the aging population. The interplay among immune dysfunction, chronic tissue inflammation, and innovative therapeutic approaches highlights the importance of elucidating these complex processes to develop effective interventions to improve the quality of life in older adults.