Metabolic Reprogramming and Reactive Oxygen Species in T Cell Immunity

Altered cancer metabolism and implications for next-generation CAR T-cell therapies

This review critically examines the evolving landscape of chimeric antigen receptor (CAR) T-cell therapy in treating solid tumors, with a particular focus on the metabolic challenges within the tumor microenvironment. CAR T-cell therapy has demonstrated remarkable success in hematologic malignancies, yet its efficacy in solid tumors remains limited. A significant barrier is the hostile milieu of the tumor microenvironment, which impairs CAR T-cell survival and function. This review delves into the metabolic adaptations of cancer cells and their impact on immune cells, highlighting the competition for nutrients and the accumulation of immunosuppressive metabolites. It also explores emerging strategies to enhance CAR T-cell metabolic fitness and persistence, including genetic engineering and metabolic reprogramming. An integrated approach, combining metabolic interventions with CAR T-cell therapy, has the potential to overcome these constraints and improve therapeutic outcomes in solid tumors.

Unraveling the Role of Reactive Oxygen Species in T Lymphocyte Signaling

Reactive oxygen species (ROS) are central to inter- and intracellular signaling. Their localized and transient effects are due to their short half-life, especially when generated in controlled amounts. Upon T cell receptor (TCR) activation, regulated ROS signaling is primarily initiated by complexes I and III of the electron transport chain (ETC). Subsequent ROS production triggers the activation of nicotinamide adenine dinucleotide phosphate oxidase 2 (NADPH oxidase 2), prolonging the oxidative signal. This signal then engages kinase signaling cascades such as the mitogen-activated protein kinase (MAPK) pathway and increases the activity of REDOX-sensitive transcription factors such as nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). To limit ROS overproduction and prevent oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant proteins such as superoxide dismutases (SODs) finely regulate signal intensity and are capable of terminating the oxidative signal when needed. Thus, oxidative signals, such as T cell activation, are well-controlled and critical for cellular communication.

Glutamine promotes human CD8+ T cells and counteracts imiquimod-induced T cell hyporesponsiveness

T cells protect tissues from cancer. Although investigations in mice showed that amino acids (AA) critically regulate T cell immunity, this remains poorly understood in humans. Here, we describe the AA composition of interstitial fluids in keratinocyte-derived skin cancers (KDSCs) and study the effect of AA on T cells using models of primary human cells and tissues. Gln contributed to ∼15% of interstitial AAs and promoted interferon gamma (IFN-γ), but not granzyme B (GzB) expression, in CD8+ T cells. Furthermore, the Toll-like receptor 7 agonist imiquimod (IMQ), a common treatment for KDSCs, down-regulated the metabolic gatekeepers c-MYC and mTORC1, as well as the AA transporter ASCT2 and intracellular Gln, Asn, Ala, and Asp in T cells. Reduced proliferation and IFN-γ expression, yet increased GzB, paralleled IMQ effects on AA. Finally, Gln was sufficient to promote IFN-γ-production in IMQ-treated T cells. Our findings indicate that Gln metabolism can be harnessed for treating KDSCs.

CD8+ T-cell metabolism is related to cerebrovascular reactivity in middle-aged adults

Cerebrovascular reactivity (CVR) decreases with advancing age, contributing to increased risk of cognitive impairment; however, the mechanisms underlying the age-related decrease in CVR are incompletely understood. Age-related changes to T cells, such as impaired mitochondrial respiration, increased inflammation, likely contribute to peripheral and cerebrovascular dysfunction in animals. However, whether T-cell mitochondrial respiration is related to cerebrovascular function in humans is not known. Therefore, we hypothesized that peripheral T-cell mitochondrial respiration would be positively associated with CVR and that T-cell glycolytic metabolism would be negatively associated with CVR. Twenty middle-aged adults (58 ± 5 yr) were recruited for this study. T cells were separated from peripheral blood mononuclear cells. Cellular oxygen consumption rate (OCR) and extracellular acidification rate (ECAR, a marker of glycolytic activity) were measured using extracellular flux analysis. CVR was quantified using the breath-hold index (BHI), which reflects the change in blood velocity in the middle-cerebral artery (MCAv) during a 30-s breath-hold. In contrast to our hypothesis, we found that basal OCR in CD8+ T cells (β = -0.59, R2 = 0.27, P = 0.019) was negatively associated with BHI. However, in accordance with our hypothesis, we found that basal ECAR (β = -2.20, R2 = 0.29, P = 0.015) and maximum ECAR (β = -50, R2 = 0.24, P = 0.029) were negatively associated with BHI in CD8+ T cells. There were no associations observed in CD4+ T cells. These associations appeared to be primarily mediated by an association with the pressor response to the breath-hold test. Overall, our findings suggest that CD8+ T-cell respiration and glycolytic activity may influence CVR in humans.NEW & NOTEWORTHY Peripheral T-cell metabolism is related to in vivo cerebrovascular reactivity in humans. Higher glycolytic metabolism in CD8+ T cells was associated with lower cerebrovascular reactivity to a breath-hold in middle-aged adults, which is possibly reflective of a more proinflammatory state in midlife.

Ex Vivo-Generated Tolerogenic Dendritic Cells: Hope for a Definitive Therapy of Autoimmune Diseases

Current therapies for autoimmune diseases are immunosuppressant agents, which have many debilitating side effects. However, dendritic cells (DCs) can induce antigen-specific tolerance. Tolerance restoration mediated by ex vivo-generated DCs can be a therapeutic approach. Therefore, in this review, we summarize the conceptual framework for developing ex vivo-generated DC strategies for autoimmune diseases. First, we will discuss the role of DCs in developing immune tolerance as a foundation for developing dendritic cell-based immunotherapy for autoimmune diseases. Then, we also discuss relevant findings from pre-clinical and clinical studies of ex vivo-generated DCs for therapy of autoimmune diseases. Finally, we discuss problems and challenges in dendritic cell therapy in autoimmune diseases. Throughout the article, we discuss autoimmune diseases, emphasizing SLE.

Nrf2 regulates the activation-driven expansion of CD4 + T-cells by differentially modulating glucose and glutamine metabolism

Upon antigenic stimulation, CD4 + T-cells undergo clonal expansion, elevating their bioenergetic demands and utilization of nutrients like glucose and glutamine. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a well-known regulator of oxidative stress, but its involvement in modulating the metabolism of CD4 + T-cells remains unexplored. Here, we elucidate the role of Nrf2 beyond the traditional antioxidation, in modulating activation-driven expansion of CD4 + T-cells by influencing their nutrient metabolism. T-cell-specific activation of Nrf2 enhances early activation and IL-2 secretion, upregulates TCR-signaling, and increases activation-driven proliferation of CD4 + T-cells. Mechanistically, high Nrf2 inhibits glucose metabolism through glycolysis but promotes glutamine metabolism via glutaminolysis to support increased T-cell proliferation. Further, Nrf2 expression is temporally regulated in activated CD4 + T-cells with elevated expression during the early activation, but decreased expression thereafter. Overall, our findings uncover a novel role of Nrf2 as a metabolic modulator of CD4 + T-cells, thus providing a framework for improving Nrf2-targeting therapies and T-cell immunotherapies.

CRISPR-Cas gene knockouts to optimize engineered T cells for cancer immunotherapy

While CAR-T and tgTCR-T therapies have exhibited noteworthy and promising outcomes in hematologic and solid tumors respectively, a set of distinct challenges remains. Consequently, the quest for novel strategies has become imperative to safeguard and more effectively release the full functions of engineered T cells. These factors are intricately linked to the success of adoptive cell therapy. Recently, CRISPR-based technologies have emerged as a major breakthrough for maintaining T cell functions. These technologies have allowed the discovery of T cells' negative regulators such as specific cell-surface receptors, cell-signaling proteins, and transcription factors that are involved in the development or maintenance of T cell dysfunction. By employing a CRISPR-genic invalidation approach to target these negative regulators, it has become possible to prevent the emergence of hypofunctional T cells. This review revisits the establishment of the dysfunctional profile of T cells before delving into a comprehensive summary of recent CRISPR-gene invalidations, with each invalidation contributing to the enhancement of engineered T cells' antitumor capacities. The narrative unfolds as we explore how these advancements were discovered and identified, marking a significant advancement in the pursuit of superior adoptive cell therapy.

Δfur mutant as a potential live attenuated vaccine (LAV) candidate protects American eels (Anguilla rostrata) from Vibrio harveyi infection

The eel farming industry is highly susceptible to Vibriosis. Although various types of vaccines against Vibriosis have been investigated, there is limited research on decreasing the virulence of Vibrions through gene knockout and utilizing it as live attenuated vaccines (LAV). In this study, we aim to develop a LAV candidate against Vibrio harveyi infection in American eels (Anguilla rostrata) using a ferric uptake regulator (fur) gene mutant strain of V. harveyi (Δfur mutant). After the eels were administrated with the Δfur mutant at the dose of 4 × 102 cfu/g body weight, the phagocytic activity of the leucocytes, plasma IgM antibody titers, activity of lysozyme and Superoxide Dismutase (SOD) enzyme, and gene expression levels of 18 immune related proteins were detected to evaluate the protection effect of the LAV. Preliminary findings suggest that the LAV achieved over 60% relative percent survival (RPS) after the American eels were challenged by a wild-type strain of V. harveyi infection on 28 and 42 days post the immunization (dpi). The protection was mainly attributed to increased plasma IgM antibody titers, higher levels of lysozyme, enhanced activity of SOD and some regulated genes encoded immune related proteins. Together, the Δfur mutant strain of V. harveyi, as a novel LAV vaccine, demonstrates promising protective effects against V. harveyi infection in American eels, thus presenting a potential candidate vaccine for fish farming.

Enhancing the efficacy of vaccinia-based oncolytic virotherapy by inhibiting CXCR2-mediated MDSC trafficking

Oncolytic virotherapy is an innovative approach for cancer treatment. However, recruitment of myeloid-derived suppressor cells (MDSCs) into the tumor microenvironment (TME) after oncolysis-mediated local inflammation leads to tumor resistance to the therapy. Using the murine malignant mesothelioma model, we demonstrated that the in situ vaccinia virotherapy recruited primarily polymorphonuclear MDSCs (PMN-MDSCs) into the TME, where they exhibited strong suppression of cytotoxic T lymphocytes in a reactive oxygen species-dependent way. Single-cell RNA sequencing analysis confirmed the suppressive profile of PMN-MDSCs at the transcriptomic level and identified CXCR2 as a therapeutic target expressed on PMN-MDSCs. Abrogating PMN-MDSC trafficking by CXCR2-specific small molecule inhibitor during the vaccinia virotherapy exhibited enhanced antitumor efficacy in 3 syngeneic cancer models, through increasing CD8+/MDSC ratios in the TME, activating cytotoxic T lymphocytes, and skewing suppressive TME into an antitumor environment. Our results warrant clinical development of CXCR2 inhibitor in combination with oncolytic virotherapy.

Metabolic instruction of the graft-versus-leukemia immunity

Allogeneic hematopoietic cell transplantation (allo-HCT) is frequently performed to cure hematological malignancies, such as acute myeloid leukemia (AML), through the graft-versus-leukemia (GVL) effect. In this immunological process, donor immune cells eliminate residual cancer cells in the patient and exert tumor control through immunosurveillance. However, GVL failure and subsequent leukemia relapse are frequent and associated with a dismal prognosis. A better understanding of the mechanisms underlying AML immune evasion is essential for developing novel therapeutic strategies to boost the GVL effect. Cellular metabolism has emerged as an essential regulator of survival and cell fate for both cancer and immune cells. Leukemia and T cells utilize specific metabolic programs, including the orchestrated use of glucose, amino acids, and fatty acids, to support their growth and function. Besides regulating cell-intrinsic processes, metabolism shapes the extracellular environment and plays an important role in cell-cell communication. This review focuses on recent advances in the understanding of how metabolism might affect the anti-leukemia immune response. First, we provide a general overview of the mechanisms of immune escape after allo-HCT and an introduction to leukemia and T cell metabolism. Further, we discuss how leukemia and myeloid cell metabolism contribute to an altered microenvironment that impairs T cell function. Next, we review the literature linking metabolic processes in AML cells with their inhibitory checkpoint ligand expression. Finally, we focus on recent findings concerning the role of systemic metabolism in sustained GVL efficacy. While the majority of evidence in the field still stems from basic and preclinical studies, we discuss translational findings and propose further avenues for bridging the gap between bench and bedside.

Novel therapeutic strategies targeting myeloid-derived suppressor cell immunosuppressive mechanisms for cancer treatment

Cancer is the leading cause of death globally superseded only by cardiovascular diseases, and novel strategies to overcome therapeutic resistance against existing cancer treatments are urgently required. Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells with potent immunosuppressive capacity against well-established anti-tumour effectors such as natural killer cells (NK cells) and T cells thereby promoting cancer initiation and progression. Critically, MDSCs are readily identified in almost all tumour types and human cancer patients, and numerous studies in the past decade have recognised their role in contributing to therapeutic resistance against all four pillars of modern cancer treatment, namely surgery, chemotherapy, radiotherapy and immunotherapy. MDSCs suppress anti-tumour immunity through a plethora of mechanisms including the well-characterised arginase 1 (Arg1), inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS)-mediated pathways, along with several other more recently discovered. MDSCs are largely absent in healthy homeostatic states and predominantly exist in pathological conditions, making them attractive therapeutic targets. However, the lack of specific markers identified for MDSCs to date greatly hindered therapeutic development, and currently there are no clinically approved drugs that specifically target MDSCs. Methods to deplete MDSCs clinically and inhibit their immunosuppressive function will be crucial in advancing cancer treatment and to overcome treatment resistance. This review provides a detailed overview of the current understandings behind the mechanisms of MDSC-mediated suppression of anti-tumour immunity, and discusses potential strategies to target MDSC immunosuppressive mechanisms to overcome therapeutic resistance.

Plasma and urine proteomics and gut microbiota analysis reveal potential factors affecting COVID-19 vaccination response

The efficacy of COVID-19 vaccination relies on the induction of neutralizing antibodies, which can vary among vaccine recipients. In this study, we investigated the potential factors affecting the neutralizing antibody response by combining plasma and urine proteomics and gut microbiota analysis. We found that activation of the LXR/FXR pathway in plasma was associated with the production of ACE2-RBD-inhibiting antibodies, while urine proteins related to complement system, acute phase response signaling, LXR/FXR, and STAT3 pathways were correlated with neutralizing antibody production. Moreover, we observed a correlation between the gut microbiota and plasma and urine proteins, as well as the vaccination response. Based on the above data, we built a predictive model for vaccination response (AUC = 0.85). Our study provides insights into characteristic plasma and urine proteins and gut microbiota associated with the ACE2-RBD-inhibiting antibodies, which could benefit our understanding of the host response to COVID-19 vaccination.

Copper overload induces apoptosis and impaired proliferation of T cell in zebrafish

Copper is an essential biometal for cell development and function, however, unbalanced copper homeostasis in T cell development and the underlying mechanisms are largely unexplored. Here, we use a zebrafish model to investigate the effect of copper overload in T cell development. We show that copper stressed zebrafish larvae exhibit a significant reduction in T cells with increased cell apoptosis and impaired cell proliferation. T cell progenitors, hematopoietic stem and progenitor cells, also exhibit increased cell apoptosis. Copper overload induces production of ROS and the down-regulations of its resistance genes foxos, and ectopic expression of foxo3a, ROS scavenger GSH, could both effectively rescue the reduction of T cells in copper overload larvae. Moreover, foxm1-cytoskeleton axis, parallel to ROS-foxo axis, also mediates the copper overload induced T cell developmental defects. Meanwhile, ROS destroys expression of cytoskeleton rather than of foxm1 in the cells to induce cell apoptosis and the impaired proliferation. The functional integrity of copper transporters cox17 and atp7b are required for copper stress in inducing T cell apoptosis and proliferation impairment. Our findings demonstrate that the down-stream ROS-foxo/cytoskeleton and foxm1-cytoskeleton signaling pathways contribute jointly to copper overload induced T cell apoptosis and proliferation defects, which are depend on the integral function of Cox17 and Atp7b, and provide new insight into the copper homeostasis in T lymphocyte development.

Mitochondrial Glutathione in Cellular Redox Homeostasis and Disease Manifestation

Mitochondria are critical for providing energy to maintain cell viability. Oxidative phosphorylation involves the transfer of electrons from energy substrates to oxygen to produce adenosine triphosphate. Mitochondria also regulate cell proliferation, metastasis, and deterioration. The flow of electrons in the mitochondrial respiratory chain generates reactive oxygen species (ROS), which are harmful to cells at high levels. Oxidative stress caused by ROS accumulation has been associated with an increased risk of cancer, and cardiovascular and liver diseases. Glutathione (GSH) is an abundant cellular antioxidant that is primarily synthesized in the cytoplasm and delivered to the mitochondria. Mitochondrial glutathione (mGSH) metabolizes hydrogen peroxide within the mitochondria. A long-term imbalance in the ratio of mitochondrial ROS to mGSH can cause cell dysfunction, apoptosis, necroptosis, and ferroptosis, which may lead to disease. This study aimed to review the physiological functions, anabolism, variations in organ tissue accumulation, and delivery of GSH to the mitochondria and the relationships between mGSH levels, the GSH/GSH disulfide (GSSG) ratio, programmed cell death, and ferroptosis. We also discuss diseases caused by mGSH deficiency and related therapeutics.

High indirect bilirubin levels as an independent predictor of postoperative myasthenic crisis: a single-center, retrospective study

Background

Thymectomy is an efficient and standard treatment strategy for patients with myasthenia gravis (MG), postoperative myasthenic crisis (POMC) is the major complication related to thymectomy and has a strongly life-threatening effect. As a biomarker, whether the bilirubin level is a risk factor for MG progression remains unclear. This study aimed to investigate the association between the preoperative bilirubin level and postoperative myasthenic crisis (POMC).

Methods

We analyzed 375 patients with MG who underwent thymectomy at Tangdu Hospital between January 2012 and September 2021. The primary outcome measurement was POMC. The association between POMC and bilirubin level was analyzed by restricted cubic spline (RCS). Indirect bilirubin (IBIL) was divided into two subgroups based on the normal upper limit of IBIL, 14 μmol/L.

Results

Compared with non-POMC group, IBIL levels were significantly higher in patients with POMC. Elevated IBIL levels were closely associated with an increased risk of POMC (p for trend = 0.002). There was a dose-response curve relationship between IBIL levels and POMC incidence (p for non-linearity = 0.93). However, DBIL levels showed a U-shaped association with POMC incidence. High IBIL level (≥14 μmol/L) was an independent predictive factor for POMC [odds ratio = 3.47, 95% confidence interval (CI): 1.56-7.8, p = 0.002]. The addition of high IBIL levels improved the prediction model performance (net reclassification index = 0.186, 95% CI: 0.039-0.334; integrated discrimination improvement = 0.0345, 95% CI: 0.005-0.065).

Conclusion

High preoperative IBIL levels, especially those exceeding the normal upper limit, could independently predict the incidence of POMC.

Manganese Enhances the Osteogenic Effect of Silicon-Hydroxyapatite Nanowires by Targeting T Lymphocyte Polarization

Biomaterials encounter considerable challenges in extensive bone defect regeneration. The amelioration of outcomes may be attainable through the orchestrated modulation of both innate and adaptive immunity. Silicon-hydroxyapatite, for instance, which solely focuses on regulating innate immunity, is inadequate for long-term bone regeneration. Herein, extra manganese (Mn)-doping is utilized for enhancing the osteogenic ability by mediating adaptive immunity. Intriguingly, Mn-doping engenders heightened recruitment of CD4+ T cells to the bone defect site, concurrently manifesting escalated T helper (Th) 2 polarization and an abatement in Th1 cell polarization. This consequential immune milieu yields a collaborative elevation of interleukin 4, secreted by Th2 cells, coupled with attenuated interferon gamma, secreted by Th1 cells. This orchestrated interplay distinctly fosters the osteogenesis of bone marrow stromal cells and effectuates consequential regeneration of the mandibular bone defect. The modulatory mechanism of Th1/Th2 balance lies primarily in the indispensable role of manganese superoxide dismutase (MnSOD) and the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK). In conclusion, this study highlights the transformative potential of Mn-doping in amplifying the osteogenic efficacy of silicon-hydroxyapatite nanowires by regulating T cell-mediated adaptive immunity via the MnSOD/AMPK pathway, thereby creating an anti-inflammatory milieu favorable for bone regeneration.

Transflammation in tissue regeneration and response to injury: How cell-autonomous inflammatory signaling mediates cell plasticity

Inflammation is a first responder against injury and infection and is also critical for the regeneration and repair of tissue after injury. The role of professional immune cells in tissue healing is well characterized. Professional immune cells respond to pathogens with humoral and cytotoxic responses; remove cellular debris through efferocytosis; secrete angiogenic cytokines and growth factors to repair the microvasculature and parenchyma. However, non-immune cells are also capable of responding to damage or pathogens. Non-immune somatic cells express pattern recognition receptors (PRRs) to detect pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). The PRRs activation leads to the release of inflammatory cytokines required for tissue defense and repair. Notably, the activation of PRRs also triggers epigenetic changes that promote DNA accessibility and cellular plasticity. Thus, non-immune cells directly respond to the local inflammatory cues and can undergo phenotypic modifications or even cell lineage transitions to facilitate tissue regeneration. This review will focus on the novel role of cell-autonomous inflammatory signaling in mediating cell plasticity, a process which is termed transflammation. We will discuss the regulation of this process by changes in the functions and expression levels of epigenetic modifiers, as well as metabolic and ROS/RNS-mediated epigenetic modulation of DNA accessibility during cell fate transition. We will highlight the recent technological developments in detecting cell plasticity and potential therapeutic applications of transflammation in tissue regeneration.

Exploring the Role of Mediterranean and Westernized Diets and Their Main Nutrients in the Modulation of Oxidative Stress in the Placenta: A Narrative Review

Oxidative stress is a major cellular event that occurs in the placenta, fulfilling critical physiological roles in non-pathological pregnancies. However, exacerbated oxidative stress is a pivotal feature of different obstetric complications, like pre-eclampsia, fetal growth restriction, and other diseases. Compelling evidence supports the relevant role of diet during pregnancy, with pleiotropic consequences for maternal well-being. The present review aims to examine the complex background between oxidative stress and placental development and function in physiological conditions, also intending to understand the relationship between different dietary patterns and the human placenta, particularly how this could influence oxidative stress processes. The effects of Westernized diets (WDs) and high-fat diets (HFDs) rich in ultra-processed foods and different additives are compared with healthy patterns such as a Mediterranean diet (MedDiet) abundant in omega 3 polyunsaturated fatty acids, monounsaturated fatty acids, polyphenols, dietary fiber, and vitamins. Although multiple studies have focused on the role of specific nutrients, mostly in animal models and in vitro, further observational and intervention studies focusing on the placental structure and function in women with different dietary patterns should be conducted to understand the precise influence of diet on this organ.

Control of CD4+ T cells to restrain inflammatory diseases via eukaryotic elongation factor 2 kinase

CD4+ T cells, particularly IL-17-secreting helper CD4+ T cells, play a central role in the inflammatory processes underlying autoimmune disorders. Eukaryotic Elongation Factor 2 Kinase (eEF2K) is pivotal in CD8+ T cells and has important implications in vascular dysfunction and inflammation-related diseases such as hypertension. However, its specific immunological role in CD4+ T cell activities and related inflammatory diseases remains elusive. Our investigation has uncovered that the deficiency of eEF2K disrupts the survival and proliferation of CD4+ T cells, impairs their ability to secrete cytokines. Notably, this dysregulation leads to heightened production of pro-inflammatory cytokine IL-17, fosters a pro-inflammatory microenvironment in the absence of eEF2K in CD4+ T cells. Furthermore, the absence of eEF2K in CD4+ T cells is linked to increased metabolic activity and mitochondrial bioenergetics. We have shown that eEF2K regulates mitochondrial function and CD4+ T cell activity through the upregulation of the transcription factor, signal transducer and activator of transcription 3 (STAT3). Crucially, the deficiency of eEF2K exacerbates the severity of inflammation-related diseases, including rheumatoid arthritis, multiple sclerosis, and ulcerative colitis. Strikingly, the use of C188-9, a small molecule targeting STAT3, mitigates colitis in a murine immunodeficiency model receiving eEF2K knockout (KO) CD4+ T cells. These findings emphasize the pivotal role of eEF2K in controlling the function and metabolism of CD4+ T cells and its indispensable involvement in inflammation-related diseases. Manipulating eEF2K represents a promising avenue for novel therapeutic approaches in the treatment of inflammation-related disorders.

Early-life atomic-bomb irradiation accelerates immunological aging and elevates immune-related intracellular reactive oxygen species

Reactive oxygen species (ROS) play an important role in immune responses; however, their excessive production and accumulation increases the risk of inflammation-related diseases. Although irradiation is known to accelerate immunological aging, the underlying mechanism is still unclear. To determine the possible involvement of ROS in this mechanism, we examined 10,023 samples obtained from 3752 atomic-bomb survivors in Hiroshima and Nagasaki, who participated in repeated biennial examinations from 2008 to 2016, for the effects of aging and radiation exposure on intracellular ROS (H2 O2 and O2 •- ) levels, percentages of T-cell subsets, and the effects of radiation exposure on the relationship between cell percentages and intracellular ROS levels in T-cell subsets. The cell percentages and intracellular ROS levels in T-cell subsets were measured using flow cytometry, with both fluorescently labeled antibodies and the fluorescent reagents, carboxy-DCFDA and hydroethidine. The percentages of naïve CD4+ and CD8+ T cells decreased with increasing age and radiation dose, while the intracellular O2 •- levels in central and effector memory CD8+ T cells increased. Additionally, when divided into three groups based on the percentages of naïve CD4+ T cells, intracellular O2 •- levels of central and effector memory CD8+ T cells were significantly elevated with the lowest radiation dose group in the naïve CD4+ T cells. Thus, the radiation exposure-induced decrease in the naïve CD4+ T cell pool size may reflect decreased immune function, resulting in increased intracellular ROS levels in central and effector memory CD8+ T cells, and increased intracellular oxidative stress.

Redox regulation of defense against bacterial and viral pathogens

There is considerable interest in the role of oxygen-derived oxidants (often termed generically reactive oxygen species), and the potential effect of exogenous antioxidants, in the pathogenesis of infectious disease. Most of the published research focuses on the inflammatory response and the concept that oxidants are pro-inflammatory and antioxidants are anti-inflammatory. The present review discusses the evidence that both oxidants and thiol antioxidants are important in the various processes of innate and adaptive immunity, focusing on the function of the immune system in the defense against pathogens, rather than its pathogenic role in inflammatory and autoimmune disease.

Emerging role of metabolic reprogramming in hyperoxia-associated neonatal diseases

Oxygen therapy is common during the neonatal period to improve survival, but it can increase the risk of oxygen toxicity. Hyperoxia can damage multiple organs and systems in newborns, commonly causing lung conditions such as bronchopulmonary dysplasia and pulmonary hypertension, as well as damage to other organs, including the brain, gut, and eyes. These conditions are collectively referred to as newborn oxygen radical disease to indicate the multi-system damage caused by hyperoxia. Hyperoxia can also lead to changes in metabolic pathways and the production of abnormal metabolites through a process called metabolic reprogramming. Currently, some studies have analyzed the mechanism of metabolic reprogramming induced by hyperoxia. The focus has been on mitochondrial oxidative stress, mitochondrial dynamics, and multi-organ interactions, such as the lung-gut, lung-brain, and brain-gut axes. In this article, we provide an overview of the major metabolic pathway changes reported in hyperoxia-associated neonatal diseases and explore the potential mechanisms of metabolic reprogramming. Metabolic reprogramming induced by hyperoxia can cause multi-organ metabolic disorders in newborns, including abnormal glucose, lipid, and amino acid metabolism. Moreover, abnormal metabolites may predict the occurrence of disease, suggesting their potential as therapeutic targets. Although the mechanism of metabolic reprogramming caused by hyperoxia requires further elucidation, mitochondria and the gut-lung-brain axis may play a key role in metabolic reprogramming.

The Illustration of Altered Glucose Dependency in Drug-Resistant Cancer Cells

A chemotherapeutic approach is crucial in malignancy management, which is often challenging due to the development of chemoresistance. Over time, chemo-resistant cancer cells rapidly repopulate and metastasize, increasing the recurrence rate in cancer patients. Targeting these destined cancer cells is more troublesome for clinicians, as they share biology and molecular cross-talks with normal cells. However, the recent insights into the metabolic profiles of chemo-resistant cancer cells surprisingly illustrated the activation of distinct pathways compared with chemo-sensitive or primary cancer cells. These distinct metabolic dynamics are vital and contribute to the shift from chemo-sensitivity to chemo-resistance in cancer. This review will discuss the important metabolic alterations in cancer cells that lead to drug resistance.

SOCS3 deletion in effector T cells confers an anti-tumorigenic role of IL-6 to the pro-tumorigenic cytokine

Interleukin (IL)-6 is abundantly expressed in the tumor microenvironment and is associated with poor patient outcomes. Here, we demonstrate that the deletion of the suppressor of cytokine signaling 3 (SOCS3) in T cells potentiates anti-tumor immune responses by conferring the anti-tumorigenic function of IL-6 in mouse and human models. In Socs3-deficient CD8+ T cells, IL-6 upregulates the expression of type I interferon (IFN)-regulated genes and enhances the anti-tumor effector function of T cells, while also modifying mitochondrial fitness to increase mitochondrial membrane potential and reactive oxygen species (ROS) levels and to promote metabolic glycolysis in the energy state. Furthermore, Socs3 deficiency reduces regulatory T cells and increases T helper 1 (Th1) cells. SOCS3 knockdown in human chimeric antigen receptor T (CAR-T) cells exhibits a strong anti-tumor response in humanized mice. Thus, genetic disruption of SOCS3 offers an avenue to improve the therapeutic efficacy of adoptive T cell therapy.

The metabolic cross-talk between cancer and T cells

The metabolic cross-talk between cancer cells and T cells dictates cancer formation and progression. These cells possess metabolic plasticity. Thus, they adapt their metabolic profile to meet their phenotypic requirements. However, the nutrient microenvironment of a tumor is a very hostile niche in which these cells are forced to compete for the available nutrients. The hyperactive metabolism of tumor cells often outcompetes the antitumorigenic CD8+ T cells while promoting the protumorigenic exhausted CD8+ T cells and T regulatory (Treg) cells. Thus, cancer cells elude the immune response and spread in an uncontrolled manner. Identifying the metabolic pathways necessary to shift the balance from a protumorigenic to an antitumorigenic immune phenotype is essential to potentiate antitumor immunity.

Pathogenic helper T cells as the novel therapeutic targets for immune-mediated intractable diseases

Allergic diseases arise from a complex interplay between immune system and environmental factors. A link between the pathogenesis of allergic diseases and type 2 immune responses has become evident, with conventional and pathogenic type 2 helper T (Th2) cells involved in both. Recently, there has been a significant development in therapeutic agents for allergic diseases: IL-5 and IL-5 receptor antagonists, Janus kinase (JAK) inhibitors, and sublingual immunotherapy (SLIT). Mepolizumab, an IL-5, and Benralizumab, an IL-5 receptor antagonist, modulate eosinophilic inflammation mediated by IL-5-producing Th2 cells. Delgocitinib shows that JAK-associated signaling is essential for the inflammatory reaction in atopic dermatitis, one of the common allergic diseases. SLIT has a significant effect on allergic rhinitis by reducing pathogenic Th2 cell numbers. More recently, novel molecules that are involved in pathogenic Th2 cell-mediated allergic diseases have been identified. These include calcitonin gene-related peptide (CGRP), reactive oxygen species (ROS) scavenging machinery regulated by the Txnip-Nrf2-Blvrb axis, and myosin light chain 9 (Myl9), which interacts with CD69. This review provides an updated view of the recent research on treatment of allergic diseases and their cause: conventional and pathogenic Th2 cells.

Indian traditional rice variety "Gathuwan" suppresses T-cell-mediated immune responses via activation of ERK/Nrf2/HO-1 signalling pathway

The impact of food on immune functions has been recognized for centuries and is now being increasingly explored for therapeutic applications. Rice, in addition to being the staple food in most developing countries, exhibits diverse complexities of phytochemicals among its wide germplasm repertoire, which supports its development as a functional food. In the present study, we have explored the immunomodulatory properties of Gathuwan rice, a local rice variety grown in Chhattisgarh, India, and traditionally used for the treatment of rheumatism. Methanolic Gathuwan Brown Rice Extract (BRE) inhibits T-cell activation and proliferation and cytokine secretion (IL-2, IL-4, IL-6 and IFN-γ) without inducing cell death. BRE exhibits radical scavenging activity in a cell-free system and decreases intracellular reactive oxygen species (ROS) and glutathione levels in lymphocytes. BRE induces nuclear translocation of the immune-regulatory transcription factor Nrf2 via activation of ERK and p-38 MAP kinase and up-regulates the expression of Nrf2-dependent genes (SOD, CAT, HO-1, GPx and TrxR) in lymphocytes. BRE treatment had no effect on cytokine secretion by lymphocytes from Nrf2 knockout mice, confirming the role of Nrf2 in the immunosuppressive effects of BRE. Feeding of Gathuwan brown rice to mice had no effect on the basal haematological parameters, but lymphocytes isolated from these mice were hypo-responsive to mitogenic stimuli. Treatment of allografts with BRE significantly prevented graft-versus-host disease (GVHD)-associated mortality and morbidity in mice. Metabolic pathway enrichment analysis of ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) data revealed a high enrichment ratio of amino acid and vitamin B metabolism pathways, and among metabolite sets, pyridoxamines, phytosphingosines, hydroxybenzaldehydes, hydroxycinnamic acids and indoles were highly enriched bioactive components. In conclusion, Gathuwan BRE suppresses T-cell-mediated immune responses by altering the cellular redox balance and activating the Nrf2 signalling pathway.

Mitochondrial fusion induced by transforming growth factor-β1 serves as a switch that governs the metabolic reprogramming during differentiation of regulatory T cells

Although metabolic reprogramming during the differentiation of regulatory T cells (Treg cells) has been extensively studied, the molecular switch to alter energy metabolism remains undefined. The present study explores the critical role of mitochondrial dynamics in the reprogramming and consequent generation of Treg cells. The results showed that during Treg cell differentiation, mitochondrial fusion but not fission led to elevation of oxygen consumption rate values, facilitation of metabolic reprogramming, and increase of number of Treg cells and expression of Foxp3 in vitro and in vivo. Mechanistically, mitochondrial fusion favored fatty acid oxidation but restricted glycolysis in Treg cells through down-regulating the expression of HIF-1α. Transforming growth factor-β1 (TGF-β1) played a crucial role in the induction of mitochondrial fusion, which activated Smad2/3, promoted the expression of PGC-1α and therefore facilitated the expression of mitochondrial fusion proteins. In conclusion, during Treg cell differentiation, TGF-β1 promotes PGC-1α-mediated mitochondrial fusion, which drives metabolic reprogramming from glycolysis to fatty acid oxidation via suppressing HIF-1α expression, and therefore favors the generation of Treg cells. The signals and proteins involved in mitochondrial fusion are potential therapeutic targets for Treg cell-related diseases.

Features of oxidative stress in alcoholism

The review considers molecular mechanisms underlying formation and development of oxidative stress (OS) in patients with alcohol dependence. The major attention is paid to the effects of ethanol and its metabolite acetaldehyde associated with additional sources of generation of reactive oxygen species (ROS) in response to exogenous ethanol. The own results of studies of the in vitro effect of ethanol and acetaldehyde on the concentration of peripheral OS markers - products of oxidative modification of proteins (protein carbonyls), lipids (lipid peroxidation products), DNA (8-hydroxy-2-deoxyguanosine, 8-OHdG) in blood plasma are presented. The changes in these parameters and the activity of antioxidant enzymes (SOD, catalase) in patients with alcohol dependence were analyzed. Own and literature data indicate that at a certain stage of the disease OS can play a protective rather than pathogenic role in the body.

Oxidative stress as a culprit in diabetic kidney disease

Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease (ESRD), and the prevalence of DKD has increased worldwide during recent years. DKD is associated with poor therapeutic outcomes in most patients, but there is limited understanding of its pathogenesis. This review suggests that oxidative stress interacts with many other factors in causing DKD. Highly active mitochondria and NAD(P)H oxidase are major sources of oxidants, and they significantly affect the risk for DKD. Oxidative stress and inflammation may be considered reciprocal causes of DKD, in that each is a cause and an effect of DKD. Reactive oxygen species (ROS) can act as second messengers in various signaling pathways and as regulators of metabolism, activation, proliferation, differentiation, and apoptosis of immune cells. Epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNAs can modulate oxidative stress. The development of new technologies and identification of new epigenetic mechanisms may provide novel opportunities for the diagnosis and treatment of DKD. Clinical trials demonstrated that novel therapies which reduce oxidative stress can slow the progression of DKD. These therapies include the NRF2 activator bardoxolone methyl, new blood glucose-lowering drugs such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists. Future studies should focus on improving early diagnosis and the development of more effective combination treatments for this multifactorial disease.

Integrative analysis revealed that distinct cuprotosis patterns reshaped tumor microenvironment and responses to immunotherapy of colorectal cancer

Background

Cuprotosis is a novel form of programmed cell death that involves direct targeting of key enzymes in the tricarboxylic acid (TCA) cycle by excess copper and may result in mitochondrial metabolic dysfunction. However, whether cuprotosis may mediate the tumor microenvironment (TME) and immune regulation in colorectal cancer (CRC) remains unclear.

Methods

Ten cuprotosis-related genes were selected and unsupervised consensus clustering was performed to identify the cuprotosis patterns and the correlated TME characteristics. Using principal component analysis, a COPsig score was established to quantify cuprotosis patterns in individual patients. The top 9 most important cuprotosis signature genes were analyzed using single-cell transcriptome data.

Results

Three distinct cuprotosis patterns were identified. The TME cell infiltration characteristics of three patterns were associated with immune-excluded, immune-desert, and immune-inflamed phenotype, respectively. Based on individual cuprotosis patterns, patients were assigned into high and low COPsig score groups. Patients with a higher COPsig score were characterized by longer overall survival time, lower immune cell as well as stromal infiltration, and greater tumor mutational burden. Moreover, further analysis demonstrated that CRC patients with a higher COPsig score were more likely to respond to immune checkpoint inhibitors and 5-fluorouracil chemotherapy. Single-cell transcriptome analysis indicated that cuprotosis signature genes recruited tumor-associated macrophages to TME through the regulation of TCA and the metabolism of glutamine and fatty acid, thus influencing the prognosis of CRC patients.

Conclusion

This study indicated that distinct cuprotosis patterns laid a solid foundation to the explanation of heterogeneity and complexity of individual TME, thus guiding more effective immunotherapy as well as adjuvant chemotherapy strategies.

TIGIT signaling and its influence on T cell metabolism and immune cell function in the tumor microenvironment

One of the key challenges for successful cancer therapy is the capacity of tumors to evade immune surveillance. Tumor immune evasion can be accomplished through the induction of T cell exhaustion via the activation of various immune checkpoint molecules. The most prominent examples of immune checkpoints are PD-1 and CTLA-4. Meanwhile, several other immune checkpoint molecules have since been identified. One of these is the T cell immunoglobulin and ITIM domain (TIGIT), which was first described in 2009. Interestingly, many studies have established a synergistic reciprocity between TIGIT and PD-1. TIGIT has also been described to interfere with the energy metabolism of T cells and thereby affect adaptive anti-tumor immunity. In this context, recent studies have reported a link between TIGIT and the hypoxia-inducible factor 1-α (HIF1-α), a master transcription factor sensing hypoxia in several tissues including tumors that among others regulates the expression of metabolically relevant genes. Furthermore, distinct cancer types were shown to inhibit glucose uptake and effector function by inducing TIGIT expression in CD8+ T cells, resulting in an impaired anti-tumor immunity. In addition, TIGIT was associated with adenosine receptor signaling in T cells and the kynurenine pathway in tumor cells, both altering the tumor microenvironment and T cell-mediated immunity against tumors. Here, we review the most recent literature on the reciprocal interaction of TIGIT and T cell metabolism and specifically how TIGIT affects anti-tumor immunity. We believe understanding this interaction may pave the way for improved immunotherapy to treat cancer.

T Cell Response to SARS-CoV-2 Coinfection and Comorbidities

For the past three years, COVID-19 has become an increasing global health issue. Adaptive immune cells, especially T cells, have been extensively investigated in regard to SARS-CoV-2 infection. However, human health and T cell responses are also impacted by many other pathogens and chronic diseases. We have summarized T cell performance during SARS-CoV-2 coinfection with other viruses, bacteria, and parasites. Furthermore, we distinguished if those altered T cell statuses under coinfection would affect their clinical outcomes, such as symptom severity and hospitalization demand. T cell alteration in diabetes, asthma, and hypertension patients with SARS-CoV-2 infection was also investigated in our study. We have summarized whether changes in T cell response influence the clinical outcome during comorbidities.

Innate and adaptive immune abnormalities underlying autoimmune diseases: the genetic connections

With the exception of an extremely small number of cases caused by single gene mutations, most autoimmune diseases result from the complex interplay between environmental and genetic factors. In a nutshell, etiology of the common autoimmune disorders is unknown in spite of progress elucidating certain effector cells and molecules responsible for pathologies associated with inflammatory and tissue damage. In recent years, population genetics approaches have greatly enriched our knowledge regarding genetic susceptibility of autoimmunity, providing us with a window of opportunities to comprehensively re-examine autoimmunity-associated genes and possible pathways. In this review, we aim to discuss etiology and pathogenesis of common autoimmune disorders from the perspective of human genetics. An overview of the genetic basis of autoimmunity is followed by 3 chapters detailing susceptibility genes involved in innate immunity, adaptive immunity and inflammatory cell death processes respectively. With such attempts, we hope to expand the scope of thinking and bring attention to lesser appreciated molecules and pathways as important contributors of autoimmunity beyond the 'usual suspects' of a limited subset of validated therapeutic targets.

Assessing the Immune Cell Subset and Genetic Mutations in Patients With Palindromic Rheumatism Seronegative for Rheumatoid Factor and Anti-Cyclic Citrullinated Peptide

OBJECTIVE

The etiology underlying cases of palindromic rheumatism (PR) not associated with other rheumatic diseases in patients who are seronegative for rheumatoid factor and anti-cyclic citrullinated peptide (seronegative PR) is unclear. We aimed to investigate the immune cells and genes involved.

METHODS

This was a single-center comparative study of 48 patients with seronegative PR and 48 healthy controls. Mass cytometry and RNA sequencing were used to identify distinct immune cell subsets in blood. Among the 48 seronegative PR patients, plasma samples from 40 patients were evaluated by enzyme-linked immunosorbent assay for cytokine levels, and peripheral blood samples from 25 patients were evaluated by flow cytometry for mononuclear cell subsets. Plasma samples from 21 patients were evaluated by real-time polymerase chain reaction for differential gene and protein expression, and samples from 3 patients were analyzed with whole-exome sequencing for gene mutations.

RESULTS

Immunophenotyping revealed a markedly increased frequency of CD14+CD11b+CD36+ and CD4+CD25-CD69+ cells in seronegative PR patients with active flares compared with healthy controls (P < 0.0001 for both cell subset comparisons). Gene enrichment analyses of RNA-sequencing data from sorted CD14+CD11b+CD36+ and CD4+CD25-CD69+ cells showed involvement of the inflammatory/stress response, phagocytosis, and regulation of apoptosis functional pathways. Up-regulated expression of CXCL16 and IL10RA was observed in monocytes from PR patients. Up-regulation of PFKFB3, DDIT4, and TGFB1, and down-regulation of PDIA6 were found in monocytes and lymphocytes from PR patients with active flares and PR patients in intercritical periods. Plasma levels of S100A8/A9 and interleukin-1β were elevated in PR patients. Whole-exome sequencing revealed novel polygenic mutations in HACL1, KDM5A, RASAL1, HAVCR2, PRDM9, MBOAT4, and JRKL.

CONCLUSION

In seronegative PR patients, we identified a distinct CD14+CD11b+CD36+ cell subset that can induce an inflammatory response under stress and exert antiinflammatory effects after phagocytosis of apoptotic cells, and a CD4+CD25-CD69+ T cell subset with pro- and antiinflammatory properties. Individuals with genetic mutations involving epigenetic modification, potentiation and resolution of stress-induced inflammation/apoptosis, and a dysregulated endoplasmic reticulum stress response could be predisposed to seronegative PR.

Xiehuo Xiaoying decoction inhibits Tfh cell expansion and promotes Tfr cell amplification to ameliorate Graves' disease

ETHNOPHARMACOLOGICAL RELEVANCE

Xiehuo Xiaoying decoction (XHXY) has shown great potential in the treatment of GD, but its mechanism remains obscure. Increase of follicular helper T (Tfh) cells and reduction of follicular regulatory T (Tfr) cells contribute to a high thyrotropin receptor antibodies (TRAb) level and possible Graves' disease (GD). Oxidative stress (OS) disrupts T helper cell differentiation and aggravates autoimmunity.

AIM OF THE STUDY

This study aimed to investigate whether XHXY decoction can ameliorate autoimmunity in GD via inhibiting OS and regulating Tfh and Tfr cells.

MATERIALS AND METHODS

The main XHXY bioactive compounds were identified using high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. GD was induced in the mice through three intramuscular injections of adenovirus expressing the TSH receptor. Then, the mice received oral gavage of XHXY (17 g/kg·d) and 34 g/kg·d) for 4 weeks. OS indicators were assessed. Flow cytometry was used to confirm the proportion of Tfh and Tfr cells in the lymph nodes and spleens of the mice. Cytokine expression levels were determined using enzyme-linked immunosorbent assay. Factors including interleukin-21, B-cell lymphoma-6, and forkhead box P3 (Foxp3) were detected using quantitative polymerase chain reaction. The mRNA and protein expression levels of Kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid-2-related factor 2 (Nrf2), and haem oxygenase 1 (HO-1) were detected using quantitative polymerase chain reaction and Western blotting, respectively.

RESULTS

Twelve main ingredients of XHXY were identified. XHXY relieved GD by lowering thyroxine (p < 0.01) and TRAb levels (p < 0.01). XHXY ameliorated OS by decreasing the levels of NADPH oxidase 2 (p < 0.05), 4-hydroxynonenal (p < 0.01), and 8-oxo-2'-deoxyguanosine (p < 0.001). It inhibited Tfh cell expansion (p < 0.05), as well as the production of cytokine interleukin -21 (p < 0.01), interleukin -4 (p < 0.01) and transcription factor B-cell lymphoma 6 (p < 0.05). XHXY also induced Tfr cell amplification (p < 0.05), increased the production of interleukin -10 (p < 0.05) and transforming growth factor β (p < 0.05) and the mRNA levels of Foxp3 (p < 0.05). Finally, the Tfh/Tfr ratio returned to normal. In addition, XHXY activated Nrf2 and HO-1 expression, but inhibited Keap1 activation.

CONCLUSIONS

XHXY relieves autoimmunity in GD via inhibiting Tfh cell amplification and Tfr cell reduction, a mechanism which probably involves the Keap1/Nrf2 signaling pathway.

Low-density lipoprotein balances T cell metabolism and enhances response to anti-PD-1 blockade in a HCT116 spheroid model

Introduction

The discovery of immune checkpoints and the development of their specific inhibitors was acclaimed as a major breakthrough in cancer therapy. However, only a limited patient cohort shows sufficient response to therapy. Hence, there is a need for identifying new checkpoints and predictive biomarkers with the objective of overcoming immune escape and resistance to treatment. Having been associated with both, treatment response and failure, LDL seems to be a double-edged sword in anti-PD1 immunotherapy. Being embedded into complex metabolic conditions, the impact of LDL on distinct immune cells has not been sufficiently addressed. Revealing the effects of LDL on T cell performance in tumor immunity may enable individual treatment adjustments in order to enhance the response to routinely administered immunotherapies in different patient populations. The object of this work was to investigate the effect of LDL on T cell activation and tumor immunity in-vitro.

Methods

Experiments were performed with different LDL dosages (LDL^low = 50 μg/ml and LDL^high = 200 μg/ml) referring to medium control. T cell phenotype, cytokines and metabolism were analyzed. The functional relevance of our findings was studied in a HCT116 spheroid model in the context of anti-PD-1 blockade.

Results

The key points of our findings showed that LDL^high skewed the CD4⁺ T cell subset into a central memory-like phenotype, enhanced the expression of the co-stimulatory marker CD154 (CD40L) and significantly reduced secretion of IL-10. The exhaustion markers PD-1 and LAG-3 were downregulated on both T cell subsets and phenotypical changes were associated with a balanced T cell metabolism, in particular with a significant decrease of reactive oxygen species (ROS). T cell transfer into a HCT116 spheroid model resulted in a significant reduction of the spheroid viability in presence of an anti-PD-1 antibody combined with LDL^high.

Discussion

Further research needs to be conducted to fully understand the impact of LDL on T cells in tumor immunity and moreover, to also unravel LDL effects on other lymphocytes and myeloid cells for improving anti-PD-1 immunotherapy. The reason for improved response might be a resilient, less exhausted phenotype with balanced ROS levels.

IL-21, Inflammatory Cytokines and Hyperpolarized CD8+ T Cells Are Central Players in Lupus Immune Pathology

Systemic lupus erythematous (SLE) is a chronic autoimmune disorder, broadly characterized by systemic inflammation along with heterogeneous clinical manifestations, severe morbidity, moribund organ failure and eventual mortality. In our study, SLE patients displayed a higher percentage of activated, inflamed and hyper-polarized CD8⁺ T cells, dysregulated CD8⁺ T cell differentiation, significantly elevated serum inflammatory cytokines and higher accumulation of cellular ROS when compared to healthy controls. Importantly, these hyper-inflammatory/hyper-polarized CD8⁺ T cells responded better to an antioxidant than to an oxidant. Terminally differentiated Tc1 cells also showed plasticity upon oxidant/antioxidant treatment, but that was in contrast to the SLE CD8⁺ T cell response. Our studies suggest that the differential phenotype and redox response of SLE CD8⁺ T cells and Tc1 cells could be attributed to their cytokine environs during their respective differentiation and eventual activation environs. The polarization of Tc1 cells with IL-21 drove hyper-cytotoxicity without hyper-polarisation suggesting that the SLE inflammatory cytokine environment could drive the extreme aberrancy in SLE CD8⁺ T cells.

Carbon dot-based nanomaterials: a promising future nano-platform for targeting tumor-associated macrophages

The tumor microenvironment (TME) is the internal environment that tumors depend on for survival and development. Tumor-associated macrophages (TAMs), as an important part of the tumor microenvironment, which plays a crucial role in the occurrence, development, invasion and metastasis of various malignant tumors and has immunosuppressant ability. With the development of immunotherapy, eradicating cancer cells by activating the innate immune system has yielded encouraging results, however only a minority of patients show a lasting response. Therefore, in vivo imaging of dynamic TAMs is crucial in patient-tailored immunotherapy to identify patients who will benefit from immunotherapy, monitor efficacy after treatment, and identify alternative strategies for non-responders. Meanwhile, developing nanomedicines based on TAMs-related antitumor mechanisms to effectively inhibit tumor growth is expected to become a promising research field. Carbon dots (CDs), as an emerging member of the carbon material family, exhibit unexpected superiority in fluorescence imaging/sensing, such as near infrared imaging, photostability, biocompatibility and low toxicity. Their characteristics naturally integrate therapy and diagnosis, and when CDs are combined with targeted chemical/genetic/photodynamic/photothermal therapeutic moieties, they are good candidates for targeting TAMs. We concentrate our discussion on the current learn of TAMs and describe recent examples of macrophage modulation based on carbon dot-associated nanoparticles, emphasizing the advantages of their multifunctional platform and their potential for TAMs theranostics.

Persistent CD38 Expression on CD8 + T Lymphocytes Contributes to Altered Mitochondrial Function and Chronic Inflammation in People With HIV, Despite ART

BACKGROUND

Age-associated comorbidities are higher in people with HIV (PWH) than HIV-negative individuals. This is partially attributed to immune activation and CD38 expression on T cells driving chronic inflammation. However, the exact contribution of CD38-expressing T cells on the proinflammatory response is not completely understood.

METHODS

CD38-expressing CD8 + T lymphocytes were measured from PWH and HIV-negative individuals. Mitochondrial mass, superoxide content, membrane depolarization of CD4 + and CD8 + T lymphocytes, and cytokine production after HIV(Gag)-specific peptide stimulation from CD38 + CD8 + T lymphocytes of PWH were measured to link biological effects of CD38 expression on cellular metabolism.

RESULTS

The frequency of activated CD8 + CD38 + T cells persists in PWH on ART compared with HIV-negative individuals. Higher CD38 expression is associated with mitochondrial biogenesis and HIV(Gag)-specific proinflammatory cytokine production in PWH. Blockade of CD38 results in lower Gag-specific cytokine production.

CONCLUSIONS

ART only partially reduced HIV-induced CD38 expression on CD8 + T cells. CD8 + CD38 + T cells are highly activated in vivo, and HIV-specific stimulation in vitro augments CD38 expression, contributing to a proinflammatory response despite virologic control with ART. Therefore, CD38 is a potential therapeutic target for mitigating chronic inflammation that likely drives cellular aging, comorbidities, and end-organ disease in PWH.

Function of gaseous hydrogen sulfide in liver fibrosis

Over the past few years, hydrogen sulfide (H₂S) has been shown to exert several biological functions in mammalian. The endogenous production of H₂S is mainly mediated by cystathione β-synthase, cystathione γ-lyase and 3-mercaptopyruvate sulfur transferase. These enzymes are broadly expressed in liver tissue and regulates liver function by working on a variety of molecular targets. As an important regulator of liver function, H₂S is critically involved in the pathogenesis of various liver diseases, such as non-alcoholic steatohepatitis and liver cancer. Targeting H₂S-generating enzymes may be a therapeutic strategy for controlling liver diseases. This review described the function of H₂S in liver disease and summarized recent characterized role of H₂S in several cellular process of the liver.

Nitrite Promotes ROS Production to Potentiate Cefoperazone-Sulbactam-Mediated Elimination to Lab-Evolved and Clinical-Evolved Pseudomonas aeruginosa

Cefoperazone-sulbactam (SCF)-resistant Pseudomonas aeruginosa poses a big challenge in the use of SCF to treat infection caused by the pathogen. We have recently shown exogenous nitrite-enabled killing of naturally and artificially evolved Pseudomonas aeruginosa strains (AP-R_CLIN-EVO and AP-R_LAB-EVO, respectively) by SCF. However, the underlying mechanism is unknown. Here, reprogramming metabolomics was adopted to investigate how nitrite enhanced the SCF-mediated killing efficacy. Nitrite-reprogrammed metabolome displayed an activated pyruvate cycle (P cycle), which was confirmed by elevated activity of pyruvate dehydrogenase (PDH), α-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase. The activated P cycle provided NADH for the electron transport chain and thereby increased reactive oxygen species (ROS), which potentiated SCF to kill AP-R_CLIN-EVO and AP-R_LAB-EVO. The nitrite-enabled killing of AP-R_CLIN-EVO and AP-R_LAB-EVO by SCF was inhibited by PDH inhibitor furfural and ROS scavenger N-Acetyl-L-cysteine but promoted by ROS promoter Fe³⁺. SCF alone could not induce ROS, but SCF-mediated killing efficacy was enhanced by ROS. In addition, the present study demonstrated that nitrite repressed antioxidants, which were partly responsible for the elevated ROS. These results reveal a nitrite-reprogrammed metabolome mechanism by which AP-R_CLIN-EVO and AP-R_LAB-EVO sensitivity to SCF is elevated.

IMPORTANCE Antibiotic-resistant Pseudomonas aeruginosa has become a real concern in hospital-acquired infections, especially in critically ill and immunocompromised patients. Understanding antibiotic resistance mechanisms and developing novel control measures are highly appreciated. We have recently shown that a reduced nitrite-dependent NO biosynthesis contributes to cefoperazone-sulbactam (SCF) resistance, which is reverted by exogenous nitrite, in both naturally and artificially evolved P. aeruginosa strains (AP-R_CLIN-EVO and AP-R_LAB-EVO, respectively). However, the mechanism is unknown. The present study reports that the nitrite-enabled killing of AP-R_CLIN-EVO and AP-R_LAB-EVO by SCF is attributed to the promoted production of reactive oxygen species (ROS). Nitrite activates the pyruvate cycle to generate NADH for the electron transport chain, which in turn promotes ROS generation. Nitrite-potentiated SCF-mediated killing is decreased by pyruvate dehydrogenase inhibitor furfural and ROS scavenger N-Acetyl-L-cysteine but increased by ROS promoter Fe³⁺. Furthermore, SCF-mediated killing is promoted by H₂O₂ in a dose-dependent manner. In addition, the combination of nitrite and H₂O₂ greatly enhances SCF-mediated killing. These results not only disclose a nitrite-ROS-potentiated SCF-mediated killing, but also show SCF-mediated killing is dependent upon ROS.

NADPH Oxidases Connecting Fatty Liver Disease, Insulin Resistance and Type 2 Diabetes: Current Knowledge and Therapeutic Outlook

Nonalcoholic fatty liver disease (NAFLD), characterized by ectopic fat accumulation in hepatocytes, is closely linked to insulin resistance and is the most frequent complication of type 2 diabetes mellitus (T2DM). One of the features connecting NAFLD, insulin resistance and T2DM is cellular oxidative stress. Oxidative stress refers to a redox imbalance due to an inequity between the capacity of production and the elimination of reactive oxygen species (ROS). One of the major cellular ROS sources is NADPH oxidase enzymes (NOX-es). In physiological conditions, NOX-es produce ROS purposefully in a timely and spatially regulated manner and are crucial regulators of various cellular events linked to metabolism, receptor signal transmission, proliferation and apoptosis. In contrast, dysregulated NOX-derived ROS production is related to the onset of diverse pathologies. This review provides a synopsis of current knowledge concerning NOX enzymes as connective elements between NAFLD, insulin resistance and T2DM and weighs their potential relevance as pharmacological targets to alleviate fatty liver disease.

Role of omega-3 polyunsaturated fatty acids, citrus pectin, and milk-derived exosomes on intestinal barrier integrity and immunity in animals

The gastrointestinal tract of livestock and poultry is prone to challenge by feedborne antigens, pathogens, and other stress factors in the farm environment. Excessive physiological inflammation and oxidative stress that arises firstly disrupts the intestinal epithelial barrier followed by other components of the gastrointestinal tract. In the present review, the interrelationship between intestinal barrier inflammation and oxidative stress that contributes to the pathogenesis of inflammatory bowel disease was described. Further, the role of naturally existing immunomodulatory nutrients such as the omega-3 polyunsaturated fatty acids, citrus pectin, and milk-derived exosomes in preventing intestinal barrier inflammation was discussed. Based on the existing evidence, the possible molecular mechanism of these bioactive nutrients in the intestinal barrier was outlined for application in animal diets.

Reactive Oxygen Species: Do They Play a Role in Adaptive Immunity?

The immune system protects the host from a plethora of microorganisms and toxins through its unique ability to distinguish self from non-self. To perform this delicate but essential task, the immune system relies on two lines of defense. The innate immune system, which is by nature fast acting, represents the first line of defense. It involves anatomical barriers, physiological factors as well as a subset of haematopoietically-derived cells generically call leukocytes. Activation of the innate immune response leads to a state of inflammation that serves to both warn about and combat the ongoing infection and delivers the antigenic information of the invading pathogens to initiate the slower but highly potent and specific second line of defense, the adaptive immune system. The adaptive immune response calls on T lymphocytes as well as the B lymphocytes essential for the elimination of pathogens and the establishment of the immunological memory. Reactive oxygen species (ROS) have been implicated in many aspects of the immune responses to pathogens, mostly in innate immune functions, such as the respiratory burst and inflammasome activation. Here in this mini review, we focus on the role of ROS in adaptive immunity. We examine how ROS contribute to T-cell biology and discuss whether this activity can be extrapolated to B cells.

Reactive Oxygen Species: Not Omnipresent but Important in Many Locations

Reactive oxygen species (ROS), such as the superoxide anion or hydrogen peroxide, have been established over decades of research as, on the one hand, important and versatile molecules involved in a plethora of homeostatic processes and, on the other hand, as inducers of damage, pathologies and diseases. Which effects ROS induce, strongly depends on the cell type and the source, amount, duration and location of ROS production. Similar to cellular pH and calcium levels, which are both strictly regulated and only altered by the cell when necessary, the redox balance of the cell is also tightly regulated, not only on the level of the whole cell but in every cellular compartment. However, a still widespread view present in the scientific community is that the location of ROS production is of no major importance and that ROS randomly diffuse from their cellular source of production throughout the whole cell and hit their redox-sensitive targets when passing by. Yet, evidence is growing that cells regulate ROS production and therefore their redox balance by strictly controlling ROS source activation as well as localization, amount and duration of ROS production. Hopefully, future studies in the field of redox biology will consider these factors and analyze cellular ROS more specifically in order to revise the view of ROS as freely flowing through the cell.

Beyond the Extra Respiration of Phagocytosis: NADPH Oxidase 2 in Adaptive Immunity and Inflammation

Reactive oxygen species (ROS) derived from the phagocyte NADPH oxidase (NOX2) are essential for host defence and immunoregulation. Their levels must be tightly controlled. ROS are required to prevent infection and are used in signalling to regulate several processes that are essential for normal immunity. A lack of ROS then leads to immunodeficiency and autoinflammation. However, excess ROS are also deleterious, damaging tissues by causing oxidative stress. In this review, we focus on two particular aspects of ROS biology: (i) the emerging understanding that NOX2-derived ROS play a pivotal role in the development and maintenance of adaptive immunity and (ii) the effects of excess ROS in systemic disease and how limiting ROS might represent a therapeutic avenue in limiting excess inflammation.

Insights Into the Pathologic Roles and Regulation of Eukaryotic Elongation Factor-2 Kinase

Eukaryotic Elongation Factor-2 Kinase (eEF2K) acts as a negative regulator of protein synthesis, translation, and cell growth. As a structurally unique member of the alpha-kinase family, eEF2K is essential to cell survival under stressful conditions, as it contributes to both cell viability and proliferation. Known as the modulator of the global rate of protein translation, eEF2K inhibits eEF2 (eukaryotic Elongation Factor 2) and decreases translation elongation when active. eEF2K is regulated by various mechanisms, including phosphorylation through residues and autophosphorylation. Specifically, this protein kinase is downregulated through the phosphorylation of multiple sites via mTOR signaling and upregulated via the AMPK pathway. eEF2K plays important roles in numerous biological systems, including neurology, cardiology, myology, and immunology. This review provides further insights into the current roles of eEF2K and its potential to be explored as a therapeutic target for drug development.

The Alterations in and the Role of the Th17/Treg Balance in Metabolic Diseases

Chronic inflammation plays an important role in the development of metabolic diseases. These include obesity, type 2 diabetes mellitus, and metabolic dysfunction-associated fatty liver disease. The proinflammatory environment maintained by the innate immunity, including macrophages and related cytokines, can be influenced by adaptive immunity. The function of T helper 17 (Th17) and regulatory T (Treg) cells in this process has attracted attention. The Th17/Treg balance is regulated by inflammatory cytokines and various metabolic factors, including those associated with cellular energy metabolism. The possible underlying mechanisms include metabolism-related signaling pathways and epigenetic regulation. Several studies conducted on human and animal models have shown marked differences in and the important roles of Th17/Treg in chronic inflammation associated with obesity and metabolic diseases. Moreover, Th17/Treg seems to be a bridge linking the gut microbiota to host metabolic disorders. In this review, we have provided an overview of the alterations in and the functions of the Th17/Treg balance in metabolic diseases and its role in regulating immune response-related glucose and lipid metabolism.