Metabolic exhaustion in infection, cancer and autoimmunity

Participation of T cells in generating immune protection against cancers

T cells are essential to the immune system's reaction. The major job of the immune system is to identify and get rid of any abnormal or malignant cells in the body. White blood cells called T cells coordinate and carry out immunological responses, including identifying and eliminating cancer cells. It mostly consists of two types called helper T-cells and cytotoxic T-cells. Together, they create an efficient reaction against cancer. Both the primary T cell subtype - CD4+ and CD8+ Tcells have specific role to play in our immune system.CD4+ T cells are limited to MHC-II molecules and acts as helper cell by activating and enhancing other immune cells. On the other side CD8+ T cells are called the killer cells as they eradicate the abnormal and contaminated cells and are limited to MHC-I molecules. The malignant cells are destroyed when cytotoxic T cells come into direct contact with them. This happens via number of processes, including TCR recognition, the release of cytotoxic chemicals, and finally the activation of the immune system. T cell receptors on the surface of cytotoxic T cells allow them to identify tumour cells and these T cells release harmful chemicals like perforins and granzymes when they connect to malignant cells. T-cells that have been stimulated release cytokines such as gamma interferon. T-cells can also acquire memory responses that improve their capacity for recognition and response. Helper T-cells contribute to the development of an immune response. It entails coordination and activation as well as the enlistment of additional immune cells, including macrophages and natural killer cells, to assist in the eradication of cancer cells. Despite the fact that the cancer frequently creates defence systems to circumvent their immune response. Together, these activities support the immune surveillance and T-cell-mediated regulation of cancer cells. Treatments like chemotherapy, radiation, and surgery are main ways to treat cancer but immunotherapy has been emerging since last few decades. These immune specific treatments have shown huge positive result. CAR T cell therapy is a promising weapon to fight again blood cancer and it works by focusing on our immune system to fight and eliminate cancer.

T cell exhaustion in human cancers

T cell exhaustion refers to a progressive state in which T cells become functionally impaired due to sustained antigenic stimulation, which is characterized by increased expression of immune inhibitory receptors, but weakened effector functions, reduced self-renewal capacity, altered epigenetics, transcriptional programme and metabolism. T cell exhaustion is one of the major causes leading to immune escape of cancer, creating an environment that supports tumor development and metastatic spread. In addition, T cell exhaustion plays a pivotal role to the efficacy of current immunotherapies for cancer. This review aims to provide a comprehensive view of roles of T cell exhaustion in cancer development and progression. We summerized the regulatory mechanisms that involved in T cell exhaustion, including transcription factors, epigenetic and metabolic reprogramming events, and various microenvironmental factors such as cytokines, microorganisms, and tumor autocrine substances. The paper also discussed the challenges posed by T cell exhaustion to cancer immunotherapies, including immune checkpoint blockade (ICB) therapies and chimeric antigen receptor T cell (CAR-T) therapy, highlightsing the obstacles encountered in ICB therapies and CAR-T therapies due to T cell exhaustion. Finally, the article provides an overview of current therapeutic options aimed to reversing or alleviating T cell exhaustion in ICB and CAR-T therapies. These therapeutic approaches seek to overcome T cell exhaustion and enhance the effectiveness of immunotherapies in treating tumors.

A Minimalist Pathogen-Like Sugar Nanovaccine for Enhanced Cancer Immunotherapy

Pathogen-mimicking nanoparticles have emerged at the forefront of vaccine delivery technology, offering potent immune activation and excellent biocompatibility. Among these innovative carriers, mannan, a critical component of yeast cell walls, shows promise as an exemplary vaccine carrier. Nevertheless, it faces challenges like unpredictable immunogenicity, rapid elimination, and limited antigen loading due to high water solubility. Herein, mannan with varying carbon chain ratios is innovatively modified, yielding a series of dodecyl chains modified mannan (Mann-C12). Through meticulous screening, a mannan variant with a 40% grafting ratio is pinpointed as the optimal vaccine carrier. Further RNA sequencing confirms that Mann-C12 exhibits desired immunostimulatory characteristics. Coupled with antigen peptides, Mann-C12/OVA257-280 nanovaccine initiates the maturation of antigen-presenting cells by activating the TLR4 and Dectin-2 pathways, significantly boosting antigen utilization and sparking antigen-specific immune responses. In vivo, experiments utilizing the B16-OVA tumor model underscore the exceptional preventive capabilities of Mann-C12/OVA257-280. Notably, when combined with immune checkpoint blockade therapy, it displays a profound synergistic effect, leading to marked inhibition of tumor growth. Thus, the work has yielded a pathogen-like nanovaccine that is both simple to prepare and highly effective, underscoring the vast potential of mannan-modified nanovaccines in the realm of cancer immunotherapy.

Insights into Immune Exhaustion in Chronic Hepatitis B: A Review of Checkpoint Receptor Expression

Hepatitis B, caused by the hepatitis B virus (HBV), often progresses to chronic infection, leading to severe complications, such as cirrhosis, liver failure, and hepatocellular carcinoma. Chronic HBV infection is characterized by a complex interplay between the virus and the host immune system, resulting in immune cell exhaustion, a phenomenon commonly observed in chronic viral infections and cancer. This state of exhaustion involves elevated levels of inhibitory molecules, cells, and cell surface receptors, as opposed to stimulatory counterparts. This review aims to elucidate the expression patterns of various co-inhibitory and co-stimulatory receptors on immune cells isolated from chronic hepatitis B (CHB) patients. By analyzing existing data, the review conducts comparisons between CHB patients and healthy adults, explores the differences between HBV-specific and total T cells in CHB patients, and examines variations between intrahepatic and peripheral immune cells in CHB patients. Understanding the mechanisms underlying immune exhaustion in CHB is crucial for developing novel immunotherapeutic approaches. This detailed analysis sheds light on the immune exhaustion observed in CHB and lays the groundwork for future combined immunotherapy strategies aimed at leveraging checkpoint receptors to restore immune function and improve clinical outcomes.

The role of CD8+ T-cells in colorectal cancer immunotherapy

Immunotherapy has been an advanced and effective approach to treating various types of solid tumors in recent years, and the most successful strategy is immune checkpoint inhibitors (ICIs), which have shown beneficial effects in patients with colorectal cancer (CRC). Drug resistance to ICIs is usually associated with CD8+ T-cells targeting tumor antigens; thus, CD8+ T-cells play an important role in immunotherapy. Unfortunately, Under continuous antigen stimulation, tumor microenvironment(TME), hypoxia and other problems it leads to insufficient infiltration of CD8+ T-cells, low efficacy and mechanism exhaustion, which have become obstacles to immunotherapy. Thus, this article describes the relationship between CRC and the immune system, focuses on the process of CD8+ T-cells production, activation, transport, killing, and exhaustion, and expounds on related mechanisms leading to CD8+ T-cells exhaustion. Finally, this article summarizes the latest strategies and methods in recent years, focusing on improving the infiltration, efficacy, and exhaustion of CD8+ T-cells, which may help to overcome the barriers to immunotherapy.

Association between Metabolic Reprogramming and Immune Regulation in Digestive Tract Tumors

BACKGROUND

The cancers of the digestive tract, including colorectal cancer (CRC), gastric cancer, and esophageal cancer, are part of the most common cancers as well as one of the most important leading causes of cancer death worldwide.

SUMMARY

Despite the emergence of immune checkpoint inhibitors (e.g., anti-CTLA-4 and anti-PD-1/PD-L1) in the past decade, offering renewed optimism in cancer treatment, only a fraction of patients derive benefit from these therapies. This limited efficacy may stem from tumor heterogeneity and the impact of metabolic reprogramming on both tumor cells and immune cells within the tumor microenvironment (TME). The metabolic reprogramming of glucose, lipids, amino acids, and other nutrients represents a pivotal hallmark of cancer, serving to generate energy, reducing equivalent and biological macromolecule, thereby fostering tumor proliferation and invasion. Significantly, the metabolic reprogramming of tumor cells can orchestrate changes within the TME, rendering patients unresponsive to immunotherapy.

KEY MESSAGES

In this review, we predominantly encapsulate recent strides on metabolic reprogramming among digestive tract cancer, especially CRC, in the TME with a focus on how these alterations influence anti-tumor immunity. Additionally, we deliberate on potential strategies to address these abnormities in metabolic pathways and the viability of combined therapy within the realm of anti-cancer immunotherapy.

The expression of CTLA-4 in hepatic alveolar echinococcosis patients and blocking CTLA-4 to reverse T cell exhaustion in Echinococcus multilocularis-infected mice

Alveolar echinococcosis (AE) is a zoonotic parasitic disease caused by the infection of Echinococcus multilocularis (E. multilocularis) larvae. Cytotoxic T-lymphocyte antigen 4 (CTLA-4) produces inhibitory signals and induces T cell exhaustion, thereby inhibiting the parasiticidal efficacy of the liver immune system. Therefore, the purpose of this study is to explore how T-cell exhaustion contributes to AE and whether blocking CTLA-4 could reverse T cell exhaustion. Here we discovered that the expression of CTLA-4 was increased in the infiltrating margin around the lesion of the liver from AE patients by using western blot and immunohistochemistry assay. Multiple fluorescence immunohistochemistry identified that CTLA-4 and CD4/CD8 molecules were co-localized. For in vitro experiments, it was found that the sustained stimulation of E. multilocularis antigen could induce T cell exhaustion, blocking CTLA-4-reversed T cell exhaustion. For in vivo experiments, the expression of CTLA-4 was increased in the liver of E. multilocularis-infected mice, and the CTLA-4 and CD4/CD8 molecules were co-localized. Flow cytometry analysis demonstrated that the percentages of both CD4+ T cells and CD8+ T cells in the liver and peripheral blood were significantly increased and induced T exhaustion. When the mice were treated with anti-CTLA-4 antibodies, the number and weight of the lesions decreased significantly. Meanwhile, the flow cytometry results suggested that blocking CTLA-4 could effectively reverse T cell exhaustion and reactivate immune function. Our work reveals that blocking CTLA-4 could effectively reverse the T cell exhaustion caused by E. multilocularis and could be used as a novel target for the treatment of AE.

Cell metabolism: Functional and phenotypic single cell approaches

Several metabolic pathways are essential for the physiological regulation of immune cells, but their dysregulation can cause immune dysfunction. Hypermetabolic and hypometabolic states represent deviations in the magnitude and flexibility of effector cells in different contexts, for example in autoimmunity, infections or cancer. To study immunometabolism, most methods focus on bulk populations and rely on in vitro activation assays. Nowadays, thanks to the development of single-cell technologies, including multiparameter flow cytometry, mass cytometry, RNA cytometry, among others, the metabolic state of individual immune cells can be measured in a variety of samples obtained in basic, translational and clinical studies. Here, we provide an overview of different single-cell approaches that are employed to investigate both mitochondrial functions and cell dependence from mitochondria metabolism. Moreover, besides the description of the appropriate experimental settings, we discuss the strengths and weaknesses of different approaches with the aim to suggest how to study cell metabolism in the settings of interest.

Ex vivo treatment with poly (I:C) alleviates the exhausted phenotype of tumor-infiltrating TCD8+ cells of gastric cancer patients

Gastric cancer is associated with the phenotypic and functional exhaustion of TCD8+ cells. On the other hand, Toll-like receptor (TLR) agonists are known to reinforce immune responses when used as adjuvants in cancer immunotherapies. Since the compromised signaling of pro-inflammatory pathways is usually associated with T cell exhaustion, the aim of the present study was to evaluate the impact of polyinosinic-polycytidylic acid (poly (I:C))-mediated TLR3 activation in restoring the normal phenotype and function of tumor-infiltrating TCD8+ cells. Peripheral blood and tumor-infiltrating TCD8+ cells of 35 gastric cancer patients were in vitro treated with increasing concentrations of poly (I:C) and the expressions of programmed death-1 (PD-1) and lymphocyte-activation gene 3 (LAG3) on these cells were examined. The peripheral TCD8+ cells of gastric cancer patients showed higher expressions of PD-1 and LAG3 along with lower proliferation compared to TCD8+ cells of the age-matched healthy control individuals. The in vitro treatment of TCD8+ cells with 100 μg/mL concentration of poly (I:C) alleviated the expression of PD-1 and LAG3 inhibitory checkpoint molecules on both peripheral and tumor-infiltrating TCD8+ cells. The mentioned dose of poly (I:C) improved the proliferation of TCD8+ cells in response to a polyclonal activator. Besides, the releases of Interferon gamma (IFN-γ) and Tumor necrosis factor alpha (TNF-α) were increased in the poly (I:C)-treated TCD8+ cells. Poly (I:C) demonstrated a potential to reduce the phenotypic and functional exhaustion of the peripheral and tumor-infiltrating TCD8+ cells and caused them to undergo more proliferation and cytokine release.

Triptolide inhibits the proinflammatory potential of myeloid-derived suppressor cells via reducing Arginase-1 in rheumatoid arthritis

Triptolide (TPT) is widely used in the treatment of rheumatoid arthritis (RA). However, its regulatory mechanisms are not fully understood. This study demonstrated that Myeloid-derived suppressor cells (MDSCs) were expanded in both RA patients and arthritic mice. The frequency of MDSCs was correlated with RA disease severity and T helper 17 (Th17) responses. MDSCs from RA patients promoted the polarization of Th17 cells in vitro, which could be substantially attenuated by blocking arginase-1 (Arg-1). TPT inhibited the differentiation of MDSCs, particularly the monocytic MDSCs (M-MDSCs) subsets, as well as the expression of Arg-1 in a dose dependent manner. Alongside, TPT treatment reduced the potential of MDSCs to promote the polarization of IL-17+ T cell in vitro. Consistently, TPT immunotherapy alleviated adjuvant-induced arthritis (AIA) in a mice model, and reduced the frequency of MDSCs, M-MDSCs and IL-17+ T cells simultaneously. The presented data suggest a pathogenic role of MDSCs in RA and may function as a novel and effective therapeutic target for TPT in RA.

Nanoparticle-Based Immunotherapy for Reversing T-Cell Exhaustion

T-cell exhaustion refers to a state of T-cell dysfunction commonly observed in chronic infections and cancer. Immune checkpoint molecules blockading using PD-1 and TIM-3 antibodies have shown promising results in reversing exhaustion, but this approach has several limitations. The treatment of T-cell exhaustion is still facing great challenges, making it imperative to explore new therapeutic strategies. With the development of nanotechnology, nanoparticles have successfully been applied as drug carriers and delivery systems in the treatment of cancer and infectious diseases. Furthermore, nanoparticle-based immunotherapy has emerged as a crucial approach to reverse exhaustion. Here, we have compiled the latest advances in T-cell exhaustion, with a particular focus on the characteristics of exhaustion that can be targeted. Additionally, the emerging nanoparticle-based delivery systems were also reviewed. Moreover, we have discussed, in detail, nanoparticle-based immunotherapies that aim to reverse exhaustion, including targeting immune checkpoint blockades, remodeling the tumor microenvironment, and targeting the metabolism of exhausted T cells, etc. These data could aid in comprehending the immunopathogenesis of exhaustion and accomplishing the objective of preventing and treating chronic diseases or cancer.

Upregulation of PD-1/PD-L1 and downregulation of immune signaling pathways lead to more severe visceral leishmaniasis in undernutrition mice

BACKGROUND

Leishmaniasis is mainly prevalent in tropical and subtropical developing countries, where chronic undernutrition often co-exists. Undernutrition is reported to promote the progression of leishmaniasis, but its immune mechanisms have not been fully elucidated.

METHODS

To simulate chronic undernutrition of patients in epidemic areas and explore the immune mechanism of undernutrition promoting leishmaniasis, BALB/c mouse models with different nutritional imbalances were established, including undernutrition 75%, undernutrition 65% and obesity mouse models. After infection with Leishmania donovani in these model mice, we focused on evaluating the progress of leishmaniasis in the spleen and liver, the expression of important immunosuppressive and immunoactivation molecules, and changes of spleen transcriptome. The immune signaling pathways enriched by differentially expressed genes and hub genes were analyzed.

RESULTS

The results showed that among the mouse infection models, undernutrition 75% + infection group had the highest parasite load in the spleen and liver at the 8th week post-infection, possibly due to the continuous increase of PD-1, PD-L1 and TCR. Spleen RNA-seq results suggested that some immune signaling pathways were downregulated in undernutrition 75% + infection group, including neutrophil extracellular trap formation, IL-17 signaling pathway, natural killer cell-mediated cytotoxicity, etc. Among them, neutrophil extracellular trap formation pathway had the largest number of downregulated genes. This also explained why undernutrition 75% + infection group had the highest parasite load. Through PPI network analysis, hub genes such as Lcn2, Ltf, Mpo, Dnaja1, Hspa1a, Hspa1b and Hsph1 were screened out and might play important roles in the process of undernutrition promoting leishmaniasis.

CONCLUSIONS

Undernutrition upregulated PD-1 and PD-L1 expression and downregulated immune signaling pathways in mice with visceral leishmaniasis. The signaling pathways and hub genes may serve as drug targets or intervention targets for the treatment of leishmaniasis patients with undernutrition.

Glycolysis-cholesterol metabolic axis in immuno-oncology microenvironment: emerging role in immune cells and immunosuppressive signaling

Cell proliferation and function require nutrients, energy, and biosynthesis activity to duplicate repertoires for each daughter. It is therefore not surprising that tumor microenvironment (TME) metabolic reprogramming primarily orchestrates the interaction between tumor and immune cells. Tumor metabolic reprogramming affords bioenergetic, signaling intermediates, and biosynthesis requirements for both malignant and immune cells. Different immune cell subsets are recruited into the TME, and these manifestations have distinct effects on tumor progression and therapeutic outcomes, especially the mutual contribution of glycolysis and cholesterol metabolism. In particularly, glycolysis-cholesterol metabolic axis interconnection plays a critical role in the TME modulation, and their changes in tumor metabolism appear to be a double-edged sword in regulating various immune cell responses and immunotherapy efficacy. Hence, we discussed the signature manifestation of the glycolysis-cholesterol metabolic axis and its pivotal role in tumor immune regulation. We also highlight how hypothetical combinations of immunotherapy and glycolysis/cholesterol-related metabolic interventions unleash the potential of anti-tumor immunotherapies, as well as developing more effective personalized treatment strategies.

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

CD8+ T cells are the key executioners of the adaptive immune arm, which mediates antitumor and antiviral immunity. Naïve CD8+ T cells develop in the thymus and are quickly activated in the periphery after encountering a cognate antigen, which induces these cells to proliferate and differentiate into effector cells that fight the initial infection. Simultaneously, a fraction of these cells become long-lived memory CD8+ T cells that combat future infections. Notably, the generation and maintenance of memory cells is profoundly affected by various in vivo conditions, such as the mode of primary activation (e.g., acute vs. chronic immunization) or fluctuations in host metabolic, inflammatory, or aging factors. Therefore, many T cells may be lost or become exhausted and no longer functional. Complicated intracellular signaling pathways, transcription factors, epigenetic modifications, and metabolic processes are involved in this process. Therefore, understanding the cellular and molecular basis for the generation and fate of memory and exhausted CD8+ cells is central for harnessing cellular immunity. In this review, we focus on mammalian target of rapamycin (mTOR), particularly signaling mediated by mTOR complex (mTORC) 2 in memory and exhausted CD8+ T cells at the molecular level.

Immunogenetic Metabolomics Reveals Key Enzymes That Modulate CAR T-cell Metabolism and Function

Immune evasion is a critical step of cancer progression that remains a major obstacle for current T cell-based immunotherapies. Hence, we investigated whether it is possible to genetically reprogram T cells to exploit a common tumor-intrinsic evasion mechanism whereby cancer cells suppress T-cell function by generating a metabolically unfavorable tumor microenvironment (TME). In an in silico screen, we identified ADA and PDK1 as metabolic regulators. We then showed that overexpression (OE) of these genes enhanced the cytolysis of CD19-specific chimeric antigen receptor (CAR) T cells against cognate leukemia cells, and conversely, ADA or PDK1 deficiency dampened this effect. ADA-OE in CAR T cells improved cancer cytolysis under high concentrations of adenosine, the ADA substrate, and an immunosuppressive metabolite in the TME. High-throughput transcriptomics and metabolomics analysis of these CAR T cells revealed alterations of global gene expression and metabolic signatures in both ADA- and PDK1-engineered CAR T cells. Functional and immunologic analyses demonstrated that ADA-OE increased proliferation and decreased exhaustion in CD19-specific and HER2-specific CAR T cells. ADA-OE improved tumor infiltration and clearance by HER2-specific CAR T cells in an in vivo colorectal cancer model. Collectively, these data unveil systematic knowledge of metabolic reprogramming directly in CAR T cells and reveal potential targets for improving CAR T-cell therapy.

Cell metabolism-based optimization strategy of CAR-T cell function in cancer therapy

Adoptive cell therapy (ACT) using chimeric antigen receptor (CAR)-modified T cells has revolutionized the field of immune-oncology, showing remarkable efficacy against hematological malignancies. However, its success in solid tumors is limited by factors such as easy recurrence and poor efficacy. The effector function and persistence of CAR-T cells are critical to the success of therapy and are modulated by metabolic and nutrient-sensing mechanisms. Moreover, the immunosuppressive tumor microenvironment (TME), characterized by acidity, hypoxia, nutrient depletion, and metabolite accumulation caused by the high metabolic demands of tumor cells, can lead to T cell "exhaustion" and compromise the efficacy of CAR-T cells. In this review, we outline the metabolic characteristics of T cells at different stages of differentiation and summarize how these metabolic programs may be disrupted in the TME. We also discuss potential metabolic approaches to improve the efficacy and persistence of CAR-T cells, providing a new strategy for the clinical application of CAR-T cell therapy.

CCDC134 facilitates T cell activation through the regulation of early T cell receptor signaling

Modulation of surface T cell antigen receptor (TCR) expression is crucial for proper T cell development and maintenance of mature T cell function at steady state and upon stimulation. We previously determined that CCDC134 (coiled-coil domain containing 134), a cytokine-like molecule that served as a potential member of the γc cytokine family, contributes to antitumor responses by augmenting CD8⁺ T cell-mediated immunity. Here we show that T cell-specific deletion of Ccdc134 decreased peripheral mature CD4⁺ and CD8⁺ T cells, which resulted in impaired T cell homeostasis. Moreover, Ccdc134-deficient T cells exhibited an attenuated response to TCR stimulation in vitro, showing lower activation and proliferative capacity. This was further reflected in vivo, rendering mice refractory to T cell-mediated inflammatory and antitumor responses. More importantly, CCDC134 is associated with TCR signaling components, including CD3ϵ, and attenuated TCR signaling in Ccdc134-deficient T cells via altered CD3ϵ ubiquitination and degradation. Taken together, these findings suggest a role for CCDC134 as a positive regulator of TCR-proximal signaling and provide insight into the cell-intrinsic functional consequences of Ccdc134 deficiency in the attenuation of T cell-mediated inflammatory and antitumor responses.

Tonic-signaling chimeric antigen receptors drive human regulatory T cell exhaustion

Regulatory T cell (Treg) therapy is a promising approach to improve outcomes in transplantation and autoimmunity. In conventional T cell therapy, chronic stimulation can result in poor in vivo function, a phenomenon termed exhaustion. Whether or not Tregs are also susceptible to exhaustion, and if so, if this would limit their therapeutic effect, was unknown. To "benchmark" exhaustion in human Tregs, we used a method known to induce exhaustion in conventional T cells: expression of a tonic-signaling chimeric antigen receptor (TS-CAR). We found that TS-CAR-expressing Tregs rapidly acquired a phenotype that resembled exhaustion and had major changes in their transcriptome, metabolism, and epigenome. Similar to conventional T cells, TS-CAR Tregs upregulated expression of inhibitory receptors and transcription factors such as PD-1, TIM3, TOX and BLIMP1, and displayed a global increase in chromatin accessibility-enriched AP-1 family transcription factor binding sites. However, they also displayed Treg-specific changes such as high expression of 4-1BB, LAP, and GARP. DNA methylation analysis and comparison to a CD8+ T cell-based multipotency index showed that Tregs naturally exist in a relatively differentiated state, with further TS-CAR-induced changes. Functionally, TS-CAR Tregs remained stable and suppressive in vitro but were nonfunctional in vivo, as tested in a model of xenogeneic graft-versus-host disease. These data are the first comprehensive investigation of exhaustion in Tregs and reveal key similarities and differences with exhausted conventional T cells. The finding that human Tregs are susceptible to chronic stimulation-driven dysfunction has important implications for the design of CAR Treg adoptive immunotherapy strategies.

Immunogenetic metabolomics revealed key enzymes that modulate CAR-T metabolism and function

Immune evasion is a critical step of cancer progression that remains a major obstacle for current T cell-based immunotherapies. Hence, we seek to genetically reprogram T cells to exploit a common tumor-intrinsic evasion mechanism, whereby cancer cells suppress T cell function by generating a metabolically unfavorable tumor microenvironment (TME). Specifically, we use an in silico screen to identify ADA and PDK1 as metabolic regulators, in which gene overexpression (OE) enhances the cytolysis of CD19-specific CD8 CAR-T cells against cognate leukemia cells, and conversely, ADA or PDK1 deficiency dampens such effect. ADA -OE in CAR-T cells improves cancer cytolysis under high concentrations of adenosine, the ADA substrate and an immunosuppressive metabolite in the TME. High-throughput transcriptomics and metabolomics in these CAR-Ts reveal alterations of global gene expression and metabolic signatures in both ADA- and PDK1- engineered CAR-T cells. Functional and immunological analyses demonstrate that ADA -OE increases proliferation and decreases exhaustion in α-CD19 and α-HER2 CAR-T cells. ADA-OE improves tumor infiltration and clearance by α-HER2 CAR-T cells in an in vivo colorectal cancer model. Collectively, these data unveil systematic knowledge of metabolic reprogramming directly in CAR-T cells, and reveal potential targets for improving CAR-T based cell therapy.

Synopsis

The authors identify the adenosine deaminase gene (ADA) as a regulatory gene that reprograms T cell metabolism. ADA-overexpression (OE) in α-CD19 and α-HER2 CAR-T cells increases proliferation, cytotoxicity, memory, and decreases exhaustion, and ADA-OE α-HER2 CAR-T cells have enhanced clearance of HT29 human colorectal cancer tumors in vivo .

Partners in crime: The feedback loop between metabolic reprogramming and immune checkpoints in the tumor microenvironment

The tumor microenvironment (TME) is a complex and constantly changing cellular system composed of heterogeneous populations of tumor cells and non-transformed stromal cells, such as stem cells, fibroblasts, endothelial cells, pericytes, adipocytes, and innate and adaptive immune cells. Tumor, stromal, and immune cells consume available nutrients to sustain their proliferation and effector functions and, as a result of their metabolism, produce a wide array of by-products that gradually alter the composition of the milieu. The resulting depletion of essential nutrients and enrichment of by-products work together with other features of the hostile TME to inhibit the antitumor functions of immune cells and skew their phenotype to promote tumor progression. This review briefly describes the participation of the innate and adaptive immune cells in recognizing and eliminating tumor cells and how the gradual metabolic changes in the TME alter their antitumor functions. In addition, we discuss the overexpression of the immune checkpoints and their ligands as a result of nutrient deprivation and by-products accumulation, as well as the amplification of the metabolic alterations induced by the immune checkpoints, which creates an immunosuppressive feedback loop in the TME. Finally, the combination of metabolic and immune checkpoint inhibitors as a potential strategy to treat cancer and enhance the outcome of patients is highlighted.

A molecular atlas of the human postmenopausal fallopian tube and ovary from single-cell RNA and ATAC sequencing

As part of the Human Cell Atlas Initiative, our goal is to generate single-cell transcriptomics (single-cell RNA sequencing [scRNA-seq], 86,708 cells) and regulatory (single-cell assay on transposase accessible chromatin sequencing [scATAC-seq], 59,830 cells) profiles of the normal postmenopausal ovary and fallopian tube (FT). The FT contains 11 major cell types, and the ovary contains 6. The dominating cell type in the FT and ovary is the stromal cell, which expresses aging-associated genes. FT epithelial cells express multiple ovarian cancer risk-associated genes (CCDC170, RND3, TACC2, STK33, and ADGB) and show active communication between fimbrial epithelial cells and ovarian stromal cells. Integrated single-cell transcriptomics and chromatin accessibility data show that the regulatory landscape of the fimbriae is different from other anatomic regions. Cell types with similar gene expression in the FT display transcriptional profiles. These findings allow us to disentangle the cellular makeup of the postmenopausal FT and ovary, advancing our knowledge of gynecologic diseases in menopause.

Activated cholesterol metabolism is integral for innate macrophage responses by amplifying Myd88 signaling

Recent studies have shown that cellular metabolism is tightly linked to the regulation of immune cells. Here, we show that activation of cholesterol metabolism, involving cholesterol uptake, synthesis, and autophagy/lipophagy, is integral to innate immune responses in macrophages. In particular, cholesterol accumulation within endosomes and lysosomes is a hallmark of the cellular cholesterol dynamics elicited by Toll-like receptor 4 activation and is required for amplification of myeloid differentiation primary response 88 (Myd88) signaling. Mechanistically, Myd88 binds cholesterol via its CLR recognition/interaction amino acid consensus domain, which promotes the protein's self-oligomerization. Moreover, a novel supramolecular compound, polyrotaxane (PRX), inhibited Myd88‑dependent inflammatory macrophage activation by decreasing endolysosomal cholesterol via promotion of cholesterol trafficking and efflux. PRX activated liver X receptor, which led to upregulation of ATP binding cassette transporter A1, thereby promoting cholesterol efflux. PRX also inhibited atherogenesis in Ldlr-/- mice. In humans, cholesterol levels in circulating monocytes correlated positively with the severity of atherosclerosis. These findings demonstrate that dynamic changes in cholesterol metabolism are mechanistically linked to Myd88‑dependent inflammatory programs in macrophages and support the notion that cellular cholesterol metabolism is integral to innate activation of macrophages and is a potential therapeutic and diagnostic target for inflammatory diseases.

Metabolic reprogramming by miRNAs in the tumor microenvironment: Focused on immunometabolism

MicroRNAs (miRNAs) are emerging as a significant modulator of immunity, and their abnormal expression/activity has been linked to numerous human disorders, such as cancer. It is now known that miRNAs potentially modulate the production of several metabolic processes in tumor-associated immune cells and indirectly via different metabolic enzymes that affect tumor-associated signaling cascades. For instance, Let-7 has been identified as a crucial modulator for the long-lasting survival of CD8+ T cells (naive phenotypes) in cancer by altering their metabolism. Furthermore, in T cells, it has been found that enhancer of zeste homolog 2 (EZH2) expression is controlled via glycolytic metabolism through miRNAs in patients with ovarian cancer. On the other hand, immunometabolism has shown us that cellular metabolic reactions and processes not only generate ATP and biosynthetic intermediates but also modulate the immune system and inflammatory processes. Based on recent studies, new and encouraging approaches to cancer involving the modification of miRNAs in immune cell metabolism are currently being investigated, providing insight into promising targets for therapeutic strategies based on the pivotal role of immunometabolism in cancer. Throughout this overview, we explore and describe the significance of miRNAs in cancer and immune cell metabolism.

Effect of Obesity among Hospitalized Cancer Patients with or without COVID-19 on a National Level

Cancer and obesity are well-known prognostic factors in COVID-19. Our objective was to study the effect of obesity (and its severity) on the risk of intensive care unit (ICU) admission, severe complications, and in-hospital mortality, in a population of cancer patients hospitalized with or without COVID-19. All patients hospitalized in France for cancer from 1 March 2020 to 28 February 2022 were included from the French national administrative database. The effect of obesity was estimated in COVID-19 and in non-COVID-19 cancer patients using logistic and survival regressions, taking into account age, sex, comorbidities, and different types of cancer. Among the 992,899 cancer patients, we identified 53,090 patients with COVID-19 (5.35%), of which 3260 were obese (6.1%). After adjustment, for patients with or without COVID-19, there is an increased risk of ICU admission or severe complications in obese patients, regardless of the type of obesity. Regarding in-hospital mortality, there is no excess risk associated with overall obesity. However, massive obesity appears to be associated with an increased risk of in-hospital mortality, with a significantly stronger effect in solid cancer patients without COVID-19 and a significantly stronger effect in hematological cancer patients with COVID-19. This study showed that in France, among hospitalized patients with cancer and with or without COVID-19, increased vigilance is needed for obese patients, both in epidemic and non-epidemic periods. This vigilance should be further strengthened in patients with massive obesity for whom the risk of in-hospital mortality is higher, particularly in epidemic periods for patients with hematological cancers.

Advancing beyond the twists and turns of T cell exhaustion in cancer

Chronic antigen stimulation leads to T cell exhaustion. Nutrient restrictions and other suppressive factors in the tumor microenvironment further exacerbate T cell dysfunction. Better understanding of heterogeneity and dynamics of exhausted CD8 T cells will guide novel therapies that modulate T cell differentiation to achieve more effective antitumor responses.

Cancer patients and COVID-19 vaccination, from safety to protocol adherence: A real-life setting report

Background

The SARS-CoV-2 pandemic has slowed down cancer prevention and treatment strategies; consequently, cancer patients are prioritized to get the COVID-19 vaccines. Being constantly threatened by a new outbreak, the dive within the immunogenicity response is of great value; nonetheless, evaluating the side effects of these vaccines on fragile patients will assure their adherence to the vaccination protocol.

Objectives

This study sets out to investigate the adverse events reported about the vaccine according to its doses and types, and to compare the prevalence and severity of toxicities across two subgroups of cancer patients, those who received the injection during active therapy cycles, and those who have not started the therapy yet at vaccination time, moreover, this paper examines the will and commitment of this population to the vaccination schemes.

Methods

This is an observational, retrospective, cohort study, in which we conducted a semi-constructed interview with 415 random solid cancer patients treated at the National Institute of Oncology in Morocco. The assessment of adverse events was carried out with a standardized scale.

Results

Eleven months after the launch of the campaign, 75.2% of patients received at least one dose of the vaccine. Altogether, the analysis demonstrates a significant difference between the adverse effects reported post the second dose compared to the first one (p=0.004; odds ratio=2 [95% CI: 1.23 - 3.31]). Besides, the results indicate an increase in the rank of the severity of systemic events (p<0.001, r=0.28) after the second dose, but not for the local events (p=0.92, r=0.005). In the adjusted subgroup analysis, no effect was detected linking active therapy with the occurrence of toxicity (p=0.51, v=0.04) as well as with the level of severity reported after both; the first and second dose. Due to the fear of interactions with the therapy, we noticed a significant trend to delay the booster dose among the participants who completed the initial vaccine protocol.

Conclusion

A considerable body of evidence exists to persuade cancer patients to take the Coronavirus vaccines, and to also follow their vaccination schemes under the supervision of their treating physicians.

T cell cholesterol efflux suppresses apoptosis and senescence and increases atherosclerosis in middle aged mice

Atherosclerosis is a chronic inflammatory disease driven by hypercholesterolemia. During aging, T cells accumulate cholesterol, potentially affecting inflammation. However, the effect of cholesterol efflux pathways mediated by ATP-binding cassette A1 and G1 (ABCA1/ABCG1) on T cell-dependent age-related inflammation and atherosclerosis remains poorly understood. In this study, we generate mice with T cell-specific Abca1/Abcg1-deficiency on the low-density-lipoprotein-receptor deficient (Ldlr^-/-) background. T cell Abca1/Abcg1-deficiency decreases blood, lymph node, and splenic T cells, and increases T cell activation and apoptosis. T cell Abca1/Abcg1-deficiency induces a premature T cell aging phenotype in middle-aged (12-13 months) Ldlr^-/- mice, reflected by upregulation of senescence markers. Despite T cell senescence and enhanced T cell activation, T cell Abca1/Abcg1-deficiency decreases atherosclerosis and aortic inflammation in middle-aged Ldlr^-/- mice, accompanied by decreased T cells in atherosclerotic plaques. We attribute these effects to T cell apoptosis downstream of T cell activation, compromising T cell functionality. Collectively, we show that T cell cholesterol efflux pathways suppress T cell apoptosis and senescence, and induce atherosclerosis in middle-aged Ldlr^-/- mice.

Semiconducting Polymer Nanoparticles for Photoactivatable Cancer Immunotherapy and Imaging of Immunoactivation

Immunotherapy that stimulates the body's own immune system to kill cancer cells has emerged as a promising cancer therapeutic method. However, some types of cancer exhibited a low response rate to immunotherapy, and the high risk of immune-related side effects has been aroused during immunotherapy, which greatly restrict its broad applications in cancer therapy. Phototherapy that uses external light to trigger the therapeutic process holds advantages including high selectivity and efficiency, and low side effects. Recently, it has been proven to be able to stimulate immune response in the tumor region by inducing immunogenic cell death (ICD), the process of which was termed photo-immunotherapy, dramatically improving therapeutic specificity over conventional immunotherapy in several aspects. Among numerous optical materials for photo-immunotherapy, semiconducting polymer nanoparticles (SPNs) have gained more and more attention owing to their excellent optical properties and good biocompatibility. In this review, we summarize recent developments of SPNs for immunotherapy and imaging of immunoactivation. Different therapeutic modalities triggered by SPNs including photo-immunotherapy and photo-immunometabolic therapy are first introduced. Then, applications of SPNs for real-time monitoring immunoactivation are discussed. Finally, the conclusion and future perspectives of this research field are given.

Imaging the Rewired Metabolism in Lung Cancer in Relation to Immune Therapy

Metabolic reprogramming is recognized as one of the hallmarks of cancer. Alterations in the micro-environmental metabolic characteristics are recognized as important tools for cancer cells to interact with the resident and infiltrating T-cells within this tumor microenvironment. Cancer-induced metabolic changes in the micro-environment also affect treatment outcomes. In particular, immune therapy efficacy might be blunted because of somatic mutation-driven metabolic determinants of lung cancer such as acidity and oxygenation status. Based on these observations, new onco-immunological treatment strategies increasingly include drugs that interfere with metabolic pathways that consequently affect the composition of the lung cancer tumor microenvironment (TME). Positron emission tomography (PET) imaging has developed a wide array of tracers targeting metabolic pathways, originally intended to improve cancer detection and staging. Paralleling the developments in understanding metabolic reprogramming in cancer cells, as well as its effects on stromal, immune, and endothelial cells, a wave of studies with additional imaging tracers has been published. These tracers are yet underexploited in the perspective of immune therapy. In this review, we provide an overview of currently available PET tracers for clinical studies and discuss their potential roles in the development of effective immune therapeutic strategies, with a focus on lung cancer. We report on ongoing efforts that include PET/CT to understand the outcomes of interactions between cancer cells and T-cells in the lung cancer microenvironment, and we identify areas of research which are yet unchartered. Thereby, we aim to provide a starting point for molecular imaging driven studies to understand and exploit metabolic features of lung cancer to optimize immune therapy.

Perivascular lymphocytic aggregates in hip prosthesis-associated adverse local tissue reactions demonstrate Th1 and Th2 activity and exhausted CD8+ cell responses

Hip implants are a successful solution for osteoarthritis; however, some individuals with metal-on-metal (MoM) and metal-on-polyethylene (MoP) prosthetics develop adverse local tissue reactions (ALTRs). While MoM and MoP ALTRs are presumed to be delayed hypersensitivity reactions to corrosion products, MoM- and MoP-associated ALTRs present with different histological characteristics. We compared MoM- and MoP-associated ALTRs histopathology with cobalt and chromium levels in serum and synovial fluid. We analyzed the gene expression levels of leukocyte aggregates and synovial fluid chemokines/cytokines to resolve potential pathophysiologic differences. In addition, we classified ALTRs from 79 patients according to their leukocyte infiltrates as macrophage-dominant, mixed, and lymphocyte-dominant. Immune-related transcript profiles from lymphocyte-dominant MoM- and MoP-associated ALTR patients with perivascular lymphocytic aggregates were similar. Cell signatures indicated predominantly macrophage, Th1 and Th2 lymphocytic infiltrate, with strong exhausted CD8⁺ signature, and low Th17 and B cell, relative to healthy lymph nodes. Lymphocyte-dominant ALTR-associated synovial fluid contained higher levels of induced protein 10 (IP-10), interleukin-1 receptor antagonist (IL-1RN), IL-8, IL-6, IL-16, macrophage inflammatory protein 1 (MIP-1α), IL-18, MCP-2, and lower cell-attracting chemokine levels, when compared with prosthetic revisions lacking ALTRs. In addition, the higher levels of IP-10, IL-8, IL-6, MIP-1α, and MCP-2 were observed within the synovial fluid of the lymphocyte-dominant ALTRs relative to the macrophage-dominant ALTRs. Not all cytokines/chemokines were detected in the perivascular aggregate transcripts, suggesting the existence of other sources in the affected synovia. Our results support the hypothesis of common hypersensitivity pathogenesis in lymphocyte-dominant MoM and MoP ALTRs. The exhausted lymphocyte signature indicates chronic processes and an impaired immune response, although the cause of the persistent T-cell activation remains unclear. The cytokine/chemokine signature of lymphocyte-dominant-associated ATLRs may be of utility for diagnosing this more aggressive pathogenesis.

A cellular census of human peripheral immune cells identifies novel cell states in lung diseases

Increasing evidence supports a central role of the immune system in lung diseases. Understanding how immunological alterations between lung diseases provide opportunities for immunotherapy. Exhausted T cells play a key role of immune suppression in lung cancer and chronic obstructive pulmonary disease was proved in our previous study. The present study aims to furthermore define molecular landscapes and heterogeneity of systemic immune cell target proteomic and transcriptomic profiles and interactions between circulating immune cells and lung residential cells in various lung diseases. We firstly measured target proteomic profiles of circulating immune cells from healthy volunteers and patients with stable pneumonia, stable asthma, acute asthma, acute exacerbation of chronic obstructive pulmonary disease, chronic obstructive pulmonary disease and lung cancer, using single-cell analysis by cytometry by time-of-flight with 42 antibodies. The nine immune cells landscape was mapped among those respiratory system diseases, including CD4+ T cells, CD8+ T cells, dendritic cells, B cells, eosinophil, γδT cells, monocytes, neutrophil and natural killer cells. The double-negative T cells and exhausted CD4+ central memory T cells subset were identified in patients with acute pneumonia. This T subset expressed higher levels of T-cell immunoglobulin and mucin domain-containing protein 3 (Tim3) and T-cell immunoreceptor with Ig and ITIM domains (TIGIT) in patients with acute pneumonia and stable pneumonia. Biological processes and pathways of immune cells including immune response activation, regulation of cell cycle and pathways in cancer in peripheral blood immune cells were defined by bulk RNA sequencing (RNA-seq). The heterogeneity among immune cells including CD4+ , CD8+ T cells and NK T cells by single immune cell RNA-seq with significant difference was found by single-cell sequencing. The effect of interstitial telocytes on the immune cell types and immune function was finally studied and the expressions of CD8a and chemokine C-C motif receptor 7 (CCR7) were increased significantly in co-cultured groups. Our data indicate that proteomic and transcriptomic profiles and heterogeneity of circulating immune cells provides new insights for understanding new molecular mechanisms of immune cell function, interaction and modulation as a source to identify and develop biomarkers and targets for lung diseases.

Juvenile idiopathic arthritis: lymphocyte activation gene-3 is a central immune receptor in children with oligoarticular subtypes

BACKGROUND

We investigated the role of inhibitory receptors (IRs) and especially lymphocyte activation gene-3 (LAG-3) in the pathogenesis of oligoarticular juvenile idiopathic arthritis (o-JIA).

METHODS

Paired samples of synovial fluid (SF) and plasma and peripheral blood (PBMCs) and synovial fluid mononuclear cells (SFMCs) were collected from o-JIA patients along with their clinical data (n = 24). Plasma from healthy controls (n = 14) and paired SF and plasma samples from five non-arthritic juvenile orthopedic patients (n = 5) served as controls. Spontaneously differentiated fibroblast-like synoviocytes (FLSs) from SFMCs were co-cultured with autologous PBMCs/SFMCs and used as ex vivo disease model. Soluble levels and cellular expressions of IRs together with their functional properties in the ex vivo model were analyzed.

RESULTS

In patients with o-JIA, soluble levels of LAG-3 and expression of LAG-3 and T cell immunoglobulin mucin03 (TIM-3) on CD3⁺CD4⁺CD45RO⁺ T cells were increased, especially in SF. Major histocompatibility complex (MHC) class II expression was induced on FLSs when these were co-cultured with autologous PBMCs/SFMCs, together with an increased monocyte chemoattractant protein-1 (MCP-1) production. In PBMC and FLS + PBMC co-cultures, neutralizing antibodies to IRs were added. Only anti-LAG-3 antibodies significantly increased MCP-1 secretion. The addition of agonistic LAG-3 antibody resulted in decreased effector cytokine secretion.

CONCLUSIONS

This is the first report comparing the effects of different IRs in o-JIA and suggests that LAG-3 might contribute to the pathogenesis of this disease.

IMPACT

This is the first study addressing the role of different co-IRs in o-JIA. We showed that LAG-3 and TIM-3 seem more important in juvenile arthritis in contrast to adult rheumatoid arthritis, where cytotoxic T-lymphocyte-associated antigen-4 and programmed cell death-1 were reported to be more important. We designed an ex vivo disease model for o-JIA, examined the effects of co-IRs in this model, and demonstrated that they might contribute to the pathogenesis of the disease. LAG-3 might play a role in o-JIA pathogenesis and might be a potential therapeutic option for o-JIA patients.

Macrophage metabolic regulation in atherosclerotic plaque

Metabolism plays a key role in controlling immune cell functions. In this review, we will discuss the diversity of plaque resident myeloid cells and will focus on their metabolic demands that could reflect on their particular intraplaque localization. Defining the metabolic configuration of plaque resident myeloid cells according to their topologic distribution could provide answers to key questions regarding their functions and contribution to disease development.

Comparison of Cancer Patients to Non-Cancer Patients among COVID-19 Inpatients at a National Level

Simple Summary

Several smaller studies have shown that COVID-19 patients with cancer are at a significantly higher risk of death. Our aim was to compare patients hospitalized for COVID-19 with cancer to those without cancer using national data and to study the effect of cancer on the risk of hospital death and intensive care unit admission. This study shows that, in France, patients with COVID-19 and cancer have a two-fold risk of death when compared to COVID-19 patients without cancer. This study also provides information about the types of cancer for which the prognosis is worse, such as hematological cancers and, among solid tumours, all metastatic cancers but also lung cancers. Our results reinforce the need to implement an organization within facilities to prevent the contamination of patients being treated for cancer and the importance of all measures of physical prevention and of vaccination.

Abstract

(1) Background: Several smaller studies have shown that COVID-19 patients with cancer are at a significantly higher risk of death. Our objective was to compare patients hospitalized for COVID-19 with cancer to those without cancer using national data and to study the effect of cancer on the risk of hospital death and intensive care unit (ICU) admission. (2) Methods: All patients hospitalized in France for COVID-19 in March–April 2020 were included from the French national administrative database, which contains discharge summaries for all hospital admissions in France. Cancer patients were identified within this population. The effect of cancer was estimated with logistic regression, adjusting for age, sex and comorbidities. (3) Results: Among the 89,530 COVID-19 patients, we identified 6201 cancer patients (6.9%). These patients were older and were more likely to be men and to have complications (acute respiratory and kidney failure, venous thrombosis, atrial fibrillation) than those without cancer. In patients with hematological cancer, admission to ICU was significantly more frequent (24.8%) than patients without cancer (16.4%) (p < 0.01). Solid cancer patients without metastasis had a significantly higher mortality risk than patients without cancer (aOR = 1.4 [1.3–1.5]), and the difference was even more marked for metastatic solid cancer patients (aOR = 3.6 [3.2–4.0]). Compared to patients with colorectal cancer, patients with lung cancer, digestive cancer (excluding colorectal cancer) and hematological cancer had a higher mortality risk (aOR = 2.0 [1.6–2.6], 1.6 [1.3–2.1] and 1.4 [1.1–1.8], respectively). (4) Conclusions: This study shows that, in France, patients with COVID-19 and cancer have a two-fold risk of death when compared to COVID-19 patients without cancer. We suggest the need to reorganize facilities to prevent the contamination of patients being treated for cancer, similar to what is already being done in some countries.

Plasma checkpoint protein levels and galectin-9 in juvenile systemic lupus erythematosus

SLE is a disease of the adaptive immune system where T lymphocyte dysfunction has an important role as well. We assessed the plasma levels of checkpoint receptors expressed on T cells, along with Galectin-9 to reflect type-1 IFN activity and IL-2Rα in childhood SLE patients. Forty-nine children with SLE and15 healthy controls were included. SLEDAI scores were evaluated at the time of sampling. CD25 (IL-2Rα), 4-1BB, B7.2 (CD86), TGF-β1, CTLA-4, PD-L1, PD-1, Tim-3, LAG- 3, Galectin-9 levels were studied by cytometric bead-based multiplex assay panel. Galectin-9 and PD-L1 were significantly higher in SLE patients. Other checkpoint proteins and IL-2Rα were also higher but did not reach statistical significance. There were significant correlations between SLEDAI and IL-2Rα, Galectin-9 and PDL1. There were three clinical clusters: Cluster 1 included patients with no major organ involvement, cluster 2 had predominantly haematological involvement(n=16) and cluster 3 (n=11) had predominantly renal involvement. Checkpoint proteins were not different among these three clusters. Our data supports that Galectin 9 and IL-2Rα are good markers for disease activity in childhood SLE. We need larger series to evaluate differences between disease clusters in SLE. We failed to show a significant correlation with checkpoint proteins and SLEDAI except for PDL1.

Pathological role of activated mTOR in CXCR3+ memory B cells of rheumatoid arthritis

OBJECTIVES

B cells play an important pathological role in rheumatoid arthritis (RA). In this study, we investigated the role of metabolic regulator mTOR in B cells and its relevance to the pathology of RA.

METHODS

Peripheral blood mononuclear cells were isolated from 31 normal subjects and 86 RA patients and the gated B cells were assessed for mTOR phosphorylation and chemokine receptor expression. In vitro studies on peripheral blood B cells isolated from the control and RA patients investigated the molecular mechanisms.

RESULTS

Higher concentrations of CXCL10 (CXCR3 ligands) and lower percentages of CXCR3+ memory B cells were present in the peripheral blood of RA patients relative to the control. RA patients with high CXCL10 concentrations had smaller percentage of CXCR3+ memory B cells and high disease activity. One-year treatment with TNF inhibitors increased the percentage of CXCR3+ memory B cells and reduced serum CXCL10 concentrations. mTOR phosphorylation in B cells was further enhanced in RA patients, compared to the control, and was selectively enhanced in CXCR3+ memory B cells. mTOR phosphorylation in CXCR3+ memory B cells correlated with disease activity. In vitro, mTOR phosphorylation in B cells enhanced IL-6 production and increased RANKL expression.

CONCLUSION

mTOR activation in CXCR3+ memory B cells of RA patients is associated with disease activity, mediated through IL-6 production and RANKL expression. The obtained results also suggest that TNF inhibitors mediate an impact on the association between CXCL10 and mTOR activated CXCR3+ memory B cells.

Exhausted T cells in systemic lupus erythematosus patients in long-standing remission

The mechanisms that drive systemic lupus erythematosus (SLE) patients to achieve remission are unknown; one possible explanation might be T cell exhaustion. The aim of the present study was to measure CD4⁺ and CD8⁺ T cell exhaustion in SLE patients in prolonged remission (PR-SLE) and compared them with patients with active SLE (Act-SLE) and healthy subjects. We included 15 PR-SLE patients, 15 Act-SLE and 29 healthy subjects. T cell exhaustion was determined by flow cytometry according to the expression of programmed cell death 1 (PD)-1, T cell immunoglobulin and mucin 3 (Tim-3), natural killer cell receptor (2B4), eomesodermin (EOMES) and T-box transcription factor TBX21 (T-bet) in CD4⁺ and CD8⁺ T cells. Dimensionality reduction using the T-distributed stochastic neighbor-embedding algorithm and clustering analysis was used for the identification of relevant populations. Percentages of CD3⁺ , CD4⁺ and CD8⁺ T cells were similar among groups. We identified five subpopulations of CD8⁺ and seven of CD4⁺ cells. The CD4⁺ T-bet⁺ CD45RO⁺ cells identified in the unsupervised analysis were significantly increased in PR-SLE versus Act-SLE [median = 0·20, interquartile range (IQR) = 1·74-30·50 versus 1·68, IQR = 0·4-2·83; P < 0·01]. CD4⁺ EOMES⁺ cells were also increased in PR-SLE versus Act-SLE (5·24, IQR = 3·38-14·70 versus 1·39, IQR = 0·48-2·87; P < 0·001). CD8⁺ EOMES⁺ cells were increased in PR-SLE versus Act-SLE (37·6, IQR = 24·9-53·2 versus 8·13, IQR = 2·33-20·5; P < 0·001). Exhausted and activated T cells presented an increased frequency of PD-1, CD57 and EOMES in SLE patients versus healthy subjects. Some subpopulations of T cells expressing markers associated with exhaustion are increased in patients in remission, supporting T cell exhaustion as a tolerance mechanism in SLE. Exhaustion of specific populations of T cells might represent a potential therapeutic tool that will contribute to the goal of achieving sustained remission in these patients.

Lactate Metabolism and Signaling in Tuberculosis and Cancer: A Comparative Review

Infection with Mycobacterium tuberculosis (Mtb) leading to tuberculosis (TB) disease continues to be a major global health challenge. Critical barriers, including but not limited to the development of multi-drug resistance, lack of diagnostic assays that detect patients with latent TB, an effective vaccine that prevents Mtb infection, and infectious and non-infectious comorbidities that complicate active TB, continue to hinder progress toward a TB cure. To complement the ongoing development of new antimicrobial drugs, investigators in the field are exploring the value of host-directed therapies (HDTs). This therapeutic strategy targets the host, rather than Mtb, and is intended to augment host responses to infection such that the host is better equipped to prevent or clear infection and resolve chronic inflammation. Metabolic pathways of immune cells have been identified as promising HDT targets as more metabolites and metabolic pathways have shown to play a role in TB pathogenesis and disease progression. Specifically, this review highlights the potential role of lactate as both an immunomodulatory metabolite and a potentially important signaling molecule during the host response to Mtb infection. While long thought to be an inert end product of primarily glucose metabolism, the cancer research field has discovered the importance of lactate in carcinogenesis and resistance to chemotherapeutic drug treatment. Herein, we discuss similarities between the TB granuloma and tumor microenvironments in the context of lactate metabolism and identify key metabolic and signaling pathways that have been shown to play a role in tumor progression but have yet to be explored within the context of TB. Ultimately, lactate metabolism and signaling could be viable HDT targets for TB; however, critical additional research is needed to better understand the role of lactate at the host-pathogen interface during Mtb infection before adopting this HDT strategy.

Tumor Microenvironment Autophagic Processes and Cachexia: The Missing Link?

Cachexia is a syndrome that affects the entire organism and presents a variable plethora of symptoms in patients, always associated with continuous and involuntary degradation of skeletal muscle mass and function loss. In cancer, this syndrome occurs in 50% of all patients, while prevalence increases to 80% as the disease worsens, reducing quality of life, treatment tolerance, therapeutic response, and survival. Both chronic systemic inflammation and immunosuppression, paradoxically, correspond to important features in cachexia patients. Systemic inflammation in cachexia is fueled by the interaction between tumor and peripheral tissues with significant involvement of infiltrating immune cells, both in the peripheral tissues and in the tumor itself. Autophagy, as a process of regulating cellular metabolism and homeostasis, can interfere with the metabolic profile in the tumor microenvironment. Under a scenario of balanced autophagy in the tumor microenvironment, the infiltrating immune cells control cytokine production and secretion. On the other hand, when autophagy is unbalanced or dysfunctional within the tumor microenvironment, there is an impairment in the regulation of immune cell’s inflammatory phenotype. The inflammatory phenotype upregulates metabolic consumption and cytokine production, not only in the tumor microenvironment but also in other tissues and organs of the host. We propose that cachexia-related chronic inflammation can be, at least, partly associated with the failure of autophagic processes in tumor cells. Autophagy endangers tumor cell viability by producing immunogenic tumor antigens, thus eliciting the immune response necessary to counteract tumor progression, while preventing the establishment of inflammation, a hallmark of cachexia. Comprehensive understanding of this complex functional dichotomy may enhance cancer treatment response and prevent/mitigate cancer cachexia. This review summarizes the recent available literature regarding the role of autophagy within the tumor microenvironment and the consequences eliciting the development of cancer cachexia.

Are All Patients with Cancer at Heightened Risk for Severe Coronavirus Disease 2019 (COVID-19)?

Cancer patients are traditionally considered at high risk for complicated respiratory viral infections, due to their underlying immunosuppression. In line with this notion, early case series reported high mortality rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with malignancy. However, subsequent large, prospective, epidemiological surveys indicate that the risk for severe coronavirus disease 2019 (COVID-19) may be largely attributed to the multiple confounders operating in this highly heterogeneous population of patients, rather than the cancer or its treatment per se. We critically discuss the conundrums of SARS-CoV-2 infection in cancer patients and underscore mechanistic insights on the outcome of COVID-19 as it relates to cancer therapy and the type and status of the underlying malignancy. Not all cancer patients are similarly at risk for a complicated COVID-19 course. A roadmap is needed for translational and clinical research on COVID-19 in this challenging group of patients.

Counteracting CAR T cell dysfunction

In spite of high rates of complete remission following chimeric antigen receptor (CAR) T cell therapy, the efficacy of this approach is limited by generation of dysfunctional CAR T cells in vivo, conceivably induced by immunosuppressive tumor microenvironment (TME) and excessive antigen exposure. Exhaustion and senescence are two critical dysfunctional states that impose a pivotal hurdle for successful CAR T cell therapies. Recently, modified CAR T cells with an "exhaustion-resistant" phenotype have shown superior antitumor functions and prolonged lifespan. In addition, several studies have indicated the feasibility of senescence delay in CAR T cells. Here, we review the latest reports regarding blockade of CAR T cell exhaustion and senescence with a particular focus on the exhaustion-inducing pathways. Subsequently, we describe what potential these latest insights offer for boosting the potency of adoptive cell transfer (ACT) therapies involving CAR T cells. Furthermore, we discuss how induction of costimulation, cytokine exposure, and TME modulation can impact on CAR T cell efficacy and persistence, while potential safety issues associated with reinvigorated CAR T cells will also be addressed.

Epigenetic Control of Cdkn2a.Arf Protects Tumor-Infiltrating Lymphocytes from Metabolic Exhaustion

T-cell exhaustion in cancer is linked to poor clinical outcomes, where evidence suggests T-cell metabolic changes precede functional exhaustion. Direct competition between tumor-infiltrating lymphocytes (TIL) and cancer cells for metabolic resources often renders T cells dysfunctional. Environmental stress produces epigenome remodeling events within TIL resulting from loss of the histone methyltransferase EZH2. Here, we report an epigenetic mechanism contributing to the development of metabolic exhaustion in TIL. A multiomics approach revealed a Cdkn2a.Arf-mediated, p53-independent mechanism by which EZH2 inhibition leads to mitochondrial dysfunction and the resultant exhaustion. Reprogramming T cells to express a gain-of-function EZH2 mutant resulted in an enhanced ability of T cells to inhibit tumor growth in vitro and in vivo. Our data suggest that manipulation of T-cell EZH2 within the context of cellular therapies may yield lymphocytes that are able to withstand harsh tumor metabolic environments and collateral pharmacologic insults. SIGNIFICANCE: These findings demonstrate that manipulation of T-cell EZH2 in cellular therapies may yield cellular products able to withstand solid tumor metabolic-deficient environments. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/21/4707/F1.large.jpg.

Calcium regulation of T cell metabolism

T cells are an essential component of the immune system that provide antigen-specific acute and long lasting immune responses to infections and tumors, ascertain the maintenance of immunological tolerance and, on the flipside, mediate autoimmunity in a variety of diseases. The activation of T cells through antigen recognition by the T cell receptor (TCR) results in transient and sustained Ca2+ signals that are shaped by the opening of Ca2+ channels in the plasma membrane and cellular organelles. The dynamic regulation of intracellular Ca2+ concentrations controls a variety of T cell functions on the timescale of seconds to days after signal initiation. Among the more recently identified roles of Ca2+ signaling in T cells is the regulation of metabolic pathways that control the function of many T cell subsets. In this review, we discuss how Ca2+ regulates several metabolic programs in T cells such as the activation of AMPK and the PI3K-AKT-mTORC1 pathway, aerobic glycolysis, mitochondrial metabolism including tricarboxylic acid (TCA) cycle function and oxidative phosphorylation (OXPHOS), as well as lipid metabolism.

Reinvigorating exhausted CD8+ cytotoxic T lymphocytes in the tumor microenvironment and current strategies in cancer immunotherapy

Immunotherapy has revolutionized the treatment of cancer in recent years and achieved overall success and long-term clinical benefit in patients with a wide variety of cancer types. However, there is still a large proportion of patients exhibiting limited or no responses to immunotherapeutic strategy, some of which were even observed with hyperprogressive disease. One major obstacle restricting the efficacy is that tumor-reactive CD8⁺ T cells, which are central for tumor control, undergo exhaustion, and lose their ability to eliminate cancer cells after infiltrating into the strongly immunosuppressive tumor microenvironment. Thus, as a potential therapeutic rationale in the development of cancer immunotherapy, targeting or reinvigorating exhausted CD8⁺ T cells has been attracting much interest. Hitherto, both intrinsic and extrinsic mechanisms that govern CD8⁺ T-cell exhaustion have been explored. Specifically, the transcriptional and epigenetic landscapes have been depicted utilizing single-cell RNA sequencing or mass cytometry (CyTOF). In addition, cellular metabolism dictating the tumor-infiltrating CD8⁺ T-cell fate is currently under investigation. A series of clinical trials are being carried out to further establish the current strategies targeting CD8⁺ T-cell exhaustion. Taken together, despite the proven benefit of immunotherapy in cancer patients, additional efforts are still needed to fully circumvent limitations of exhausted T cells in the treatment. In this review, we will focus on the current cellular and molecular understanding of metabolic changes, epigenetic remodeling, and transcriptional regulation in CD8⁺ T-cell exhaustion and describe hypothetical treatment approaches based on immunotherapy aiming at reinvigorating exhausted CD8⁺ T cells.

Exhausted CD4+ T Cells during Malaria Exhibit Reduced mTORc1 Activity Correlated with Loss of T-bet Expression

CD4⁺ T cell functional inhibition (exhaustion) is a hallmark of malaria and correlates with impaired parasite control and infection chronicity. However, the mechanisms of CD4⁺ T cell exhaustion are still poorly understood. In this study, we show that Ag-experienced (Ag-exp) CD4⁺ T cell exhaustion during Plasmodium yoelii nonlethal infection occurs alongside the reduction in mammalian target of rapamycin (mTOR) activity and restriction in CD4⁺ T cell glycolytic capacity. We demonstrate that the loss of glycolytic metabolism and mTOR activity within the exhausted Ag-expCD4⁺ T cell population during infection coincides with reduction in T-bet expression. T-bet was found to directly bind to and control the transcription of various mTOR and metabolism-related genes within effector CD4⁺ T cells. Consistent with this, Ag-expTh1 cells exhibited significantly higher and sustained mTOR activity than effector T-bet- (non-Th1) Ag-expT cells throughout the course of malaria. We identified mTOR to be redundant for sustaining T-bet expression in activated Th1 cells, whereas mTOR was necessary but not sufficient for maintaining IFN-γ production by Th1 cells. Immunotherapy targeting PD-1, CTLA-4, and IL-27 blocked CD4⁺ T cell exhaustion during malaria infection and was associated with elevated T-bet expression and a concomitant increased CD4⁺ T cell glycolytic metabolism. Collectively, our data suggest that mTOR activity is linked to T-bet in Ag-expCD4⁺ T cells but that reduction in mTOR activity may not directly underpin Ag-expTh1 cell loss and exhaustion during malaria infection. These data have implications for therapeutic reactivation of exhausted CD4⁺ T cells during malaria infection and other chronic conditions.

Immunometabolism and HIV-1 pathogenesis: food for thought

Antiretroviral therapies efficiently block HIV-1 replication but need to be maintained for life. Moreover, chronic inflammation is a hallmark of HIV-1 infection that persists despite treatment. There is, therefore, an urgent need to better understand the mechanisms driving HIV-1 pathogenesis and to identify new targets for therapeutic intervention. In the past few years, the decisive role of cellular metabolism in the fate and activity of immune cells has been uncovered, as well as its impact on the outcome of infectious diseases. Emerging evidence suggests that immunometabolism has a key role in HIV-1 pathogenesis. The metabolic pathways of CD4⁺ T cells and macrophages determine their susceptibility to infection, the persistence of infected cells and the establishment of latency. Immunometabolism also shapes immune responses against HIV-1, and cell metabolic products are key drivers of inflammation during infection. In this Review, we summarize current knowledge of the links between HIV-1 infection and immunometabolism, and we discuss the potential opportunities and challenges for therapeutic interventions.

Human herpesvirus 6A promotes glycolysis in infected T cells by activation of mTOR signaling

Human herpesvirus 6 (HHV-6) is an important immunosuppressive and immunomodulatory virus worldwide. However, whether and how HHV-6 infection influences the metabolic machinery of the host cell to provide the energy and biosynthetic resources for virus propagation remains unknown. In this study, we identified that HHV-6A infection promotes glucose metabolism in infected T cells, resulting in elevated glycolytic activity with an increase of glucose uptake, glucose consumption and lactate secretion. Furthermore, we explored the mechanisms involved in HHV-6A-mediated glycolytic activation in the infected T cells. We found increased expressions of the key glucose transporters and glycolytic enzymes in HHV-6A-infected T cells. In addition, HHV-6A infection dramatically activated AKT-mTORC1 signaling in the infected T cells and pharmacological inhibition of mTORC1 blocked HHV-6A-mediated glycolytic activation. We also found that direct inhibition of glycolysis by 2-Deoxy-D-glucose (2-DG) or inhibition of mTORC1 activity in HHV-6A-infected T cells effectively reduced HHV-6 DNA replication, protein synthesis and virion production. These results not only reveal the mechanism of how HHV-6 infection affects host cell metabolism, but also suggest that targeting the metabolic pathway could be a new avenue for HHV-6 therapy.

Receptor signaling, transcriptional, and metabolic regulation of T cell exhaustion

Exhaustion cripples T cell effector responses against metastatic cancers and chronic infections alike. There has been considerable interest in understanding the molecular and cellular mechanisms driving T cell exhaustion in human cancers fueled by the success of immunotherapy drugs especially the checkpoint receptor blockade (CRB) inhibitory antibodies that reverses T cell functional exhaustion. The current understanding of molecular mechanism of T cell exhaustion has been elucidated from the studies utilizing murine models of chronic viral infections. These studies have formed the basis for much of our understanding of the process of exhaustion and proven vital to developing anti-exhaustion therapies against human cancers. In this review, we discuss the T cell exhaustion differentiation pathway in cancers and chronic viral infections and explore how the transcription factors expression dynamics play role in T cell exhaustion fate choices and maturation. Finally, we summarize the role of some of the most important transcription factors involved in T cell functional exhaustion and construct exhaustion specific signaling pathway maps.

Decreased HLA-DQ expression on peripheral blood cells in children with varying number of beta cell autoantibodies

The risk for type 1 diabetes is strongly associated with HLA-DQ and the appearance of beta cell autoantibodies against either insulin, glutamate decarboxylase (GAD65), insulinoma-associated protein-2 (IA-2), or zinc transporter 8 (ZnT8). Prolonged exposure to autoantibodies may be related to T cell exhaustion known to occur in chronic infections or autoimmune disorders. It was hypothesized that autoantibody exposure may affect HLA-DQ expression on peripheral blood cells and thereby contribute to T cell exhaustion thought to be associated with the pathogenesis of type 1 diabetes. The aim of this study was to determine whether autoantibody exposure as an expression of autoimmunity burden was related to peripheral blood cell HLA-DQ cell surface expression in either 1) a cross-sectional analysis or 2) cumulative as area under the trajectory of autoantibodies during long term follow-up in the Diabetes Prediction in Skåne (DiPiS) study. Children (n = 67), aged 10–15 years were analyzed for complete blood count, HLA-DQ cell surface median fluorescence intensity (MFI), autoantibody frequency, and HLA genotypes by Next Generation Sequencing. Decreased HLA-DQ cell surface MFI with an increasing number of autoantibodies was observed in CD16⁺, CD14⁺CD16⁻, CD4⁺ and CD8⁺ cells but not in CD19⁺ cells and neutrophils. HLA-DQ cell surface MFI was associated with HLA-DQ2/8 in CD4⁺ T cells, marginally in CD14⁺CD16⁻ monocytes and CD8⁺ T cells. These associations appeared to be related to autoimmunity burden. The results suggest that HLA-DQ cell surface expression was related to HLA and autoimmunity burden.

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PBMC HLA-DQ surface expression in beta cell autoimmunity is poorly understood.

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Children, 10–15 years of age without or with beta cell autoantibodies were analyzed.

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HLA-DQ cell surface expression decreased with increasing number of autoantibodies.

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HLA-DQ cell surface expression was related to HLA and autoimmunity burden.