Targeting memory T cell metabolism to improve immunity

Mitochondria Dictate Function and Fate of HSCs and T Cells

Hematopoietic stem cells (HSC) and T cells are intimately related, lineage-dependent cell populations that are extensively used as therapeutic products for the treatment of hematologic malignancies and certain types of solid tumors. These cellular therapies can be life-saving treatments; however, their efficacies are often limited by factors influencing their activity and cellular properties. Among these factors is mitochondrial metabolism, which influences the function and fate commitment of both HSCs and T cells. Mitochondria, besides being the "cellular powerhouse," provide metabolic intermediates that are used as substrates for epigenetic modifications and chromatin remodeling, thus, driving cell fate decisions during differentiation. Moreover, mitochondrial fitness and mitochondrial quality control mechanisms are closely related to cellular function, and impairment of these mitochondrial properties associates with cellular dysfunction due to factors such as T-cell exhaustion and aging. Here, we give an overview of the role of mitochondria in shaping the behavior of these lineage-related cell populations. Moreover, we discuss the potential of novel mitochondria-targeting strategies for enhancing HSC- and T cell-based cancer immunotherapies and highlight how design and application of such approaches requires consideration of the metabolic similarities and differences between HSCs and T cells. See related article on p. 1302.

Curcumin alleviated dextran sulfate sodium-induced colitis by recovering memory Th/Tfh subset balance

BACKGROUND

Restoration of immune homeostasis by targeting the balance between memory T helper (mTh) cells and memory follicular T helper (mTfh) cells is a potential therapeutic strategy against ulcerative colitis (UC). Because of its anti-inflammatory and immunomodulatory properties, curcumin (Cur) is a promising drug for UC treatment. However, fewer studies have demonstrated whether Cur can modulate the mTh/mTfh subset balance in mice with colitis.

AIM

To explore the potential mechanism underlying Cur-mediated alleviation of colitis induced by dextran sulfate sodium (DSS) in mice by regulating the mTh and mTfh immune homeostasis.

METHODS

Balb/c mice were administered 3% and 2% DSS to establish the UC model and treated with Cur (200 mg/kg/d) by gavage on days 11-17. On the 18th d, all mice were anesthetized and euthanized, and the colonic length, colonic weight, and colonic weight index were evaluated. Histomorphological changes in the mouse colon were observed through hematoxylin-eosin staining. Levels of Th/mTh and Tfh/mTfh cell subsets in the spleen were detected through flow cytometry. Western blotting was performed to detect SOCS-1, SOCS-3, STAT3, p-STAT3, JAK1, p-JAK1, and NF-κB p65 protein expression levels in colon tissues.

RESULTS

Cur effectively mitigates DSS-induced colitis, facilitates the restoration of mouse weight and colonic length, and diminishes the colonic weight and colonic weight index. Simultaneously, it hinders ulcer development and inflammatory cell infiltration in the colonic mucous membrane. While the percentage of Th1, mTh1, Th7, mTh7, Th17, mTh17, Tfh1, mTfh1, Tfh7, mTfh7, Tfh17, and mTfh17 cells decreased after Cur treatment of the mice for 7 d, and the frequency of mTh10, Th10, mTfh10, and Tfh10 cells in the mouse spleen increased. Further studies revealed that Cur administration prominently decreased the SOCS-1, SOCS-3, STAT3, p-STAT3, JAK1, p-JAK1, and NF-κB p65 protein expression levels in the colon tissue.

CONCLUSION

Cur regulated the mTh/mTfh cell homeostasis to reduce DSS-induced colonic pathological damage, potentially by suppressing the JAK1/STAT3/SOCS signaling pathway.

Vitamin D combined with compound glutamine for treatment of mesenteric lymphadenitis in preschool children: Efficacy and effect on cellular immune function

BACKGROUND

Mesenteric lymphadenitis (ML) is a major cause of acute diarrhoea in children and affects their health. The etiology of ML is not fully understood and is generally thought to be caused by respiratory viral or bacterial infections, which are closely related to immunocompromise. Vitamin D and compound glutamine have been shown to have immune-regulating effects. This study was conducted to investigate the effects of vitamin D combined with compound glutamine in children with ML.

AIM

To evaluate the efficacy of vitamin D combined with compound glutamine in the treatment of ML in preschool children and analyze its influence on cellular immune function.

METHODS

A total of 180 preschool children with ML treated at our hospital from December 2019 to December 2022 were included and randomly divided into either a control group or a study group. The control group (90 cases) was treated with compound glutamine alone, and the study group (90 cases) was treated with vitamin D combined with compound glutamine for 7 d. The therapeutic effects, adverse reactions, time to improvement of clinical symptoms, serum inflammatory factors [tumor necrosis factor-α (TNF-α), procalcitonin (PCT), and interleukin-8 (IL-8)], immune function indicators [immunoglobulin (Ig)A, IgG, CD3⁺ T cells, and CD4⁺/CD8⁺ ratio], and imaging indicators (lymph) were compared between the two groups. The patients were followed for 2 mo after treatment, and the recurrence rate of abdominal pain was statistically compared between the two groups.

RESULTS

The total effective rate of the study group was 92.22% (83/90) compared with 86.67% (78/90) of the control group (P > 0.05). Fever subsided, abdominal pain disappeared, nausea/vomiting disappeared, and lymph node enlargement disappeared in a shorter time in the study group than in the control group (P < 0.05). The levels of serum PCT, TNF-α, and IL-8 in the study group were significantly lower than those in the control group after 3 days of treatment (P < 0.05). The serum levels of IgA, IgG, CD3⁺ T cells and CD4⁺/CD8⁺ ratio in the study group were higher than those in the control group after 3 days of treatment (P < 0.05). After 3 days of treatment, the longitudinal and transverse diameters of lymph nodes in the study group were shorter than those in the control group (P < 0.05). The incidence of adverse reactions in the study group was 2.22% (2/90) compared with 3.33% (3/90) in the control group (P > 0.05), and the recurrence rate of abdominal pain in the study group was 5.56% (5/90), lower than that in the control group (14.44%, 13/90) (P < 0.05).

CONCLUSION

Vitamin D combined with compound glutamine in the treatment of preschool children with ML is safe and effective, can significantly inhibit the inflammatory response, improve immune function, promote the regression of symptoms, accelerate the recovery of disease, and reduce the recurrence rate.

Ligand-based adoptive T cell targeting CA125 in ovarian cancer

BACKGROUND

Ovarian cancer (OC) is a highly aggressive gynecological malignancy prevalent worldwide. Most OC cases are typically diagnosed at advanced stages, which has led to a 5-year overall survival rate of less than 35% following conventional treatment. Furthermore, immune checkpoint inhibitor therapy has shown limited efficacy in the treatment of patients with OC, and CAR-T therapy has also demonstrated modest results owing to inadequate T cell infiltration. Therefore, novel strategies must be developed to enhance T cell persistence and trafficking within the OC tumor microenvironment.

METHODS

In this study, we developed a novel adoptive T-cell therapy for ovarian cancer based on a chimeric antigen receptor structure. We used a ligand-receptor binding motif to enhance the therapeutic effect of targeting CA125. Since mesothelin can naturally bind to CA125 with high affinity, we concatenated the core-binding fragment of mesothelin with the 4-1BB and CD3ζ signal fragments to assemble a novel CA125-targeting chimeric receptor (CR). The CAR structure targeting CA125 derived from the 4H11 antibody was also constructed. CR- and CAR-encoding RNA were electroporated into T cells to evaluate their antitumor activity both in vitro and in vivo.

RESULTS

While CR-T or CAR-T cells exhibited moderate activity against two ovarian cancer cell lines, T cells co-expressing CR and CAR exhibited a superior killing effect compared to T cells expressing either CR or CAR alone. Furthermore, upon interaction with ovarian tumors, the ability of CR and CAR T cells to release activation markers and functional cytokines increased significantly. Similarly, CR and CAR co-expressing T cells persistently controlled the growth of transplanted ovarian cancer tumors in NSG mice and significantly prolonged the overall survival of tumor-challenged mice. Transcriptome sequencing revealed that the survival and cytotoxicity of T cells co-expressing CR and CAR were significantly altered compared with those of T cells expressing either CR or CAR.

CONCLUSION

Our findings demonstrate that CA125 targeting CR and CAR can synergistically kill ovarian cancer cells, indicating that CA125 targeting by the two binding motifs simultaneously in tumors may improve the therapeutic outcomes of ovarian cancer treatment.

Intracellular spatiotemporal metabolism in connection to target engagement

The metabolism in eukaryotic cells is a highly ordered system involving various cellular compartments, which fluctuates based on physiological rhythms. Organelles, as the smallest independent sub-cell unit, are important contributors to cell metabolism and drug metabolism, collectively designated intracellular metabolism. However, disruption of intracellular spatiotemporal metabolism can lead to disease development and progression, as well as drug treatment interference. In this review, we systematically discuss spatiotemporal metabolism in cells and cell subpopulations. In particular, we focused on metabolism compartmentalization and physiological rhythms, including the variation and regulation of metabolic enzymes, metabolic pathways, and metabolites. Additionally, the intricate relationship among intracellular spatiotemporal metabolism, metabolism-related diseases, and drug therapy/toxicity has been discussed. Finally, approaches and strategies for intracellular spatiotemporal metabolism analysis and potential target identification are introduced, along with examples of potential new drug design based on this.

Insights into the tumor-stromal-immune cell metabolism cross talk in ovarian cancer

The ovarian cancer tumor microenvironment (TME) consists of a constellation of abundant cellular components, extracellular matrix, and soluble factors. Soluble factors, such as cytokines, chemokines, structural proteins, extracellular vesicles, and metabolites, are critical means of noncontact cellular communication acting as messengers to convey pro- or antitumorigenic signals. Vast advancements have been made in our understanding of how cancer cells adapt their metabolism to meet environmental demands and utilize these adaptations to promote survival, metastasis, and therapeutic resistance. The stromal TME contribution to this metabolic rewiring has been relatively underexplored, particularly in ovarian cancer. Thus, metabolic activity alterations in the TME hold promise for further study and potential therapeutic exploitation. In this review, we focus on the cellular components of the TME with emphasis on 1) metabolic signatures of ovarian cancer; 2) understanding the stromal cell network and their metabolic cross talk with tumor cells; and 3) how stromal and tumor cell metabolites alter intratumoral immune cell metabolism and function. Together, these elements provide insight into the metabolic influence of the TME and emphasize the importance of understanding how metabolic performance drives cancer progression.

The immune checkpoint protein PD-1: Its emerging regulatory role in memory T cells

Immunological memory helps the body rapidly develop immune defense when it re-encounters a bacterial or viral strain or encounters a similar mutation in healthy cells. The immune checkpoint molecule programmed cell death 1 (PD-1) influences memory T cell differentiation. However, the mechanism by which PD-1 regulates the development and maintenance of memory T cells and its impact on memory T cells function remain unclear. In this review, we first discuss the structure and function of PD-1 and then summarize the roles of PD-1 as a marker of tumor memory T cells and in tumor immunotherapy. We also discuss the potential mechanisms through which PD-1 regulates memory T cells development and maintenance during immune diseases such as viral infection-mediated diseases, psoriasis, and rheumatoid arthritis, and list the effects of PD-1 on memory T cells in pregnancy and their function in maternal-fetal immune balance. A complete understanding of how PD-1 influences the development, maintenance, and function of memory T cells will provide new insights into the prevention and treatment of immune-related diseases.

A therapy that modulates T lymphocyte subsets in patients infected with Epstein-Barr virus: Ganciclovir combined with interferon atomization inhalation

To investigate the effect of ganciclovir combined with interferon atomization inhalation on T lymphocyte subsets in patients with Epstein-Barr virus (EBV) infection and its efficacy. Fifty patients with EBV infection who received ganciclovir combined with interferon atomization inhalation were selected as the observation group, and 50 healthy people were selected as the control group. The changes of T lymphocyte subsets in peripheral blood were detected by flow cytometry before treatment and at the 1st, 2nd, 3rd and 4th cycle after treatment. Before treatment, the CD3+, CD4+, CD4+/CD8+ indexes of the patients were significantly lower than those of the control group (P < .05), and the CD8+ level was significantly increased (P < .05). After one cycle of treatment, there was no significant difference in the changes of T lymphocyte subsets compared with those before treatment. After 2 and 3 cycles of treatment, CD3+, CD4+, CD4+/CD8+ values were higher than those before treatment (P > .05), and CD8+ index was lower than that before treatment (P < .05). After the 4th cycle of treatment, CD3+, CD4+, CD4+/CD8+ values were significantly improved (P < .05), and CD8+ index was significantly decreased (P < .05). Ganciclovir combined with interferon atomization inhalation can regulate the changes of T lymphocyte subsets in patients with EBV infection, improve the patient's condition, and has no obvious adverse reactions. Monitoring the changes of T lymphocyte subsets during treatment is more meaningful to predict the therapeutic effect of patients with EB virus infection.

Epigenetic drugs as new emerging therapeutics: What is the scale's orientation of application and challenges?

Epigenetics is the study of heritable changes in gene expression or function without altering the DNA sequence. Important factors are part of epigenetic events, such as methylation, DNA histone rearrangements, nucleosome transposition, and non-coding RNAs. Dysregulated epigenetic mechanics are associated with various cancers' initiation, development, and metastasis. It is known that the occurrence and development of cancer can be controlled by regulating unexpected epigenetic events. Epi-drugs are used singly or in combination with chemotherapy and enhance antitumor activity, reduce drug resistance, and stimulate the host immune response. Despite these benefits, epigenetic therapy as a single therapy or in combination with other drugs leads to adverse effects. This review article introduces and compares the advantages, disadvantages, and side effects of using these drugs for the first time since their introduction. Also, this article describes the mechanism of action of various epigenetic drugs. Recommendations for future use of epigenetic drugs as cancer therapeutics are suggested as an overall conclusion.

Impact of maximal exercise on immune cell mobilization and bioenergetics

Acute aerobic exercise increases the number and proportions of circulating peripheral blood mononuclear cells (PMBC) and can alter PBMC mitochondrial bioenergetics. In this study, we aimed to examine the impact of a maximal exercise bout on immune cell metabolism in collegiate swimmers. Eleven (7 M/4F) collegiate swimmers completed a maximal exercise test to measure anaerobic power and capacity. Pre- and postexercise PBMCs were isolated to measure the immune cell phenotypes and mitochondrial bioenergetics using flow cytometry and high-resolution respirometry. The maximal exercise bout increased circulating levels of PBMCs, particularly in central memory (KLRG1+/CD57-) and senescent (KLRG1+/CD57+) CD8+ T cells, whether measured as a % of PMBCs or as absolute concentrations (all p < 0.05). At the cellularlevel, the routine oxygen flow (IO₂ [pmol·s^-1 ·10⁶ PBMCs^-1 ]) increased following maximal exercise (p = 0.042); however, there were no effects of exercise on the IO₂ measured under the LEAK, oxidative phosphorylation (OXPHOS), or electron transfer (ET) capacities. There were exercise-induced increases in the tissue-level oxygen flow (IO_2-tissue [pmol·s^-1 ·mL blood^-1 ]) for all respiratory states (all p < 0.01), except for the LEAK state, after accounting for the mobilization of PBMCs. Future subtype-specific studies are needed to characterize further maximal exercise's true impact on immune cell bioenergetics.

Mitochondrial Dysfunction: At the Nexus between Alcohol-Associated Immunometabolic Dysregulation and Tissue Injury

Alcohol misuse, directly or indirectly as a result of its metabolism, negatively impacts most tissues, including four with critical roles in energy metabolism regulation: the liver, pancreas, adipose, and skeletal muscle. Mitochondria have long been studied for their biosynthetic roles, such as ATP synthesis and initiation of apoptosis. However, current research has provided evidence that mitochondria participate in myriad cellular processes, including immune activation, nutrient sensing in pancreatic β-cells, and skeletal muscle stem and progenitor cell differentiation. The literature indicates that alcohol impairs mitochondrial respiratory capacity, promoting reactive oxygen species (ROS) generation and disrupting mitochondrial dynamics, leading to dysfunctional mitochondria accumulation. As discussed in this review, mitochondrial dyshomeostasis emerges at a nexus between alcohol-disrupted cellular energy metabolism and tissue injury. Here, we highlight this link and focus on alcohol-mediated disruption of immunometabolism, which refers to two distinct, yet interrelated processes. Extrinsic immunometabolism involves processes whereby immune cells and their products influence cellular and/or tissue metabolism. Intrinsic immunometabolism describes immune cell fuel utilization and bioenergetics that affect intracellular processes. Alcohol-induced mitochondrial dysregulation negatively impacts immunometabolism in immune cells, contributing to tissue injury. This review will present the current state of literature, describing alcohol-mediated metabolic and immunometabolic dysregulation from a mitochondrial perspective.

Simultaneous targeting of PD-1 and IL-2Rβγ with radiation therapy inhibits pancreatic cancer growth and metastasis

In pancreatic ductal adenocarcinoma (PDAC) patients, we show that response to radiation therapy (RT) is characterized by increased IL-2Rβ and IL-2Rγ along with decreased IL-2Rα expression. The bispecific PD1-IL2v is a PD-1-targeted IL-2 variant (IL-2v) immunocytokine with engineered IL-2 cis targeted to PD-1 and abolished IL-2Rα binding, which enhances tumor-antigen-specific T cell activation while reducing regulatory T cell (Treg) suppression. Using PD1-IL2v in orthotopic PDAC KPC-driven tumor models, we show marked improvement in local and metastatic survival, along with a profound increase in tumor-infiltrating CD8+ T cell subsets with a transcriptionally and metabolically active phenotype and preferential activation of antigen-specific CD8+ T cells. In combination with single-dose RT, PD1-IL2v treatment results in a robust, durable expansion of polyfunctional CD8+ T cells, T cell stemness, tumor-specific memory immune response, natural killer (NK) cell activation, and decreased Tregs. These data show that PD1-IL2v leads to profound local and distant response in PDAC.

Systems Immunology Approaches to Metabolism

Over the last decade, immunometabolism has emerged as a novel interdisciplinary field of research and yielded significant fundamental insights into the regulation of immune responses. Multiple classical approaches to interrogate immunometabolism, including bulk metabolic profiling and analysis of metabolic regulator expression, paved the way to appreciating the physiological complexity of immunometabolic regulation in vivo. Studying immunometabolism at the systems level raised the need to transition towards the next-generation technology for metabolic profiling and analysis. Spatially resolved metabolic imaging and computational algorithms for multi-modal data integration are new approaches to connecting metabolism and immunity. In this review, we discuss recent studies that highlight the complex physiological interplay between immune responses and metabolism and give an overview of technological developments that bear the promise of capturing this complexity most directly and comprehensively.

Lipid metabolism in Th17 cell function

Among the subset of T helper cells, Th17 cells are known to play a crucial role in the pathogenesis of various autoimmune disorders, such as psoriasis, rheumatoid arthritis, inflammatory bowel disease, steroid-resistant asthma, and multiple sclerosis. The master transcription factor retinoid-related orphan receptor gamma t (RORγt), a nuclear hormone receptor, plays a vital role in inducing Th17-cell differentiation. Recent findings suggest that metabolic control is critical for Th17-cell differentiation, particularly through the engagement of de novo lipid biosynthesis. Inhibition of lipid biosynthesis, either through the use of pharmacological inhibitors or by the deficiency of related enzymes in CD4⁺ T cells, results in significant suppression of Th17-cell differentiation. Mechanistic studies indicate that metabolic fluxes through both the fatty acid and cholesterol biosynthetic pathways are essential for controlling RORγt activity through the generation of a lipid ligand of RORγt. This review highlights recent findings that underscore the significant role of lipid metabolism in the differentiation and function of Th17 cells, as well as elucidating the distinctive molecular pathways that drive the activation of RORγt by cellular lipid metabolism. We further elaborate on a pioneering therapeutic approach for ameliorating autoimmune disorders via the inhibition of RORγt.

Metabolic dysregulation impairs lymphocyte function during severe SARS-CoV-2 infection

Cellular metabolic dysregulation is a consequence of SARS-CoV-2 infection that is a key determinant of disease severity. However, how metabolic perturbations influence immunological function during COVID-19 remains unclear. Here, using a combination of high-dimensional flow cytometry, cutting-edge single-cell metabolomics, and re-analysis of single-cell transcriptomic data, we demonstrate a global hypoxia-linked metabolic switch from fatty acid oxidation and mitochondrial respiration towards anaerobic, glucose-dependent metabolism in CD8⁺Tc, NKT, and epithelial cells. Consequently, we found that a strong dysregulation in immunometabolism was tied to increased cellular exhaustion, attenuated effector function, and impaired memory differentiation. Pharmacological inhibition of mitophagy with mdivi-1 reduced excess glucose metabolism, resulting in enhanced generation of SARS-CoV-2- specific CD8⁺Tc, increased cytokine secretion, and augmented memory cell proliferation. Taken together, our study provides critical insight regarding the cellular mechanisms underlying the effect of SARS-CoV-2 infection on host immune cell metabolism, and highlights immunometabolism as a promising therapeutic target for COVID-19 treatment.

Distinct transcriptomic and epigenomic modalities underpin human memory T cell subsets and their activation potential

Human memory T cells (MTC) are poised to rapidly respond to antigen re-exposure. Here, we derived the transcriptional and epigenetic programs of resting and ex vivo activated, circulating CD4+ and CD8+ MTC subsets. A progressive gradient of gene expression from naïve to TCM to TEM is observed, which is accompanied by corresponding changes in chromatin accessibility. Transcriptional changes suggest adaptations of metabolism that are reflected in altered metabolic capacity. Other differences involve regulatory modalities comprised of discrete accessible chromatin patterns, transcription factor binding motif enrichment, and evidence of epigenetic priming. Basic-helix-loop-helix factor motifs for AHR and HIF1A distinguish subsets and predict transcription networks to sense environmental changes. Following stimulation, primed accessible chromatin correlate with an augmentation of MTC gene expression as well as effector transcription factor gene expression. These results identify coordinated epigenetic remodeling, metabolic, and transcriptional changes that enable MTC subsets to ultimately respond to antigen re-encounters more efficiently.

Berberine governs NOTCH3/AKT signaling to enrich lung-resident memory T cells during tuberculosis

Stimulation of naïve T cells during primary infection or vaccination drives the differentiation and expansion of effector and memory T cells that mediate immediate and long-term protection. Despite self-reliant rescue from infection, BCG vaccination, and treatment, long-term memory is rarely established against Mycobacterium tuberculosis (M.tb) resulting in recurrent tuberculosis (TB). Here, we show that berberine (BBR) enhances innate defense mechanisms against M.tb and stimulates the differentiation of Th1/Th17 specific effector memory (TEM), central memory (TCM), and tissue-resident memory (TRM) responses leading to enhanced host protection against drug-sensitive and drug-resistant TB. Through whole proteome analysis of human PBMCs derived from PPD+ healthy individuals, we identify BBR modulated NOTCH3/PTEN/AKT/FOXO1 pathway as the central mechanism of elevated TEM and TRM responses in the human CD4+ T cells. Moreover, BBR-induced glycolysis resulted in enhanced effector functions leading to superior Th1/Th17 responses in human and murine T cells. This regulation of T cell memory by BBR remarkably enhanced the BCG-induced anti-tubercular immunity and lowered the rate of TB recurrence due to relapse and re-infection. These results thus suggest tuning immunological memory as a feasible approach to augment host resistance against TB and unveil BBR as a potential adjunct immunotherapeutic and immunoprophylactic against TB.

Extracellular Vesicle-Based SARS-CoV-2 Vaccine

Messenger ribonucleic acid (RNA) vaccines are mainly used as SARS-CoV-2 vaccines. Despite several issues concerning storage, stability, effective period, and side effects, viral vector vaccines are widely used for the prevention and treatment of various diseases. Recently, viral vector-encapsulated extracellular vesicles (EVs) have been suggested as useful tools, owing to their safety and ability to escape from neutral antibodies. Herein, we summarize the possible cellular mechanisms underlying EV-based SARS-CoV-2 vaccines.

Immune dysregulation in Glycogen Storage Disease 1b - a CyTOF approach

Glycogen Storage Disease type 1b (GSD1b) is a rare disease manifesting as hypoglycemia, recurrent infections and neutropenia, resulting from deleterious mutations in the SLC37A4 gene encoding the glucose-6-phosphate transporter. The susceptibility to infections is thought to be attributed not only to the neutrophil defect, though extensive immunophenotyping characterization is currently missing. Here we apply a systems immunology approach utilizing Cytometry by Time Of Flight (CyTOF) to map the peripheral immune landscape of 6 GSD1b patients. When compared to control subjects, those with GSD1b had a significant reduction in anti-inflammatory macrophages, CD16+ macrophages, and Natural Killer cells. Additionally, there was a preference towards a central versus an effector memory phenotype in multiple T cell populations, which may suggest that these changes stem from an inability of activated immune cell populations to undergo the appropriate switch to glycolytic metabolism in the hypoglycemic conditions associated with GSD1b. Furthermore, we identified a global reduction of CD123, CD14, CCR4, CD24 and CD11b across several populations and a multi-cluster upregulation of CXCR3, hinting at a potential role of impaired immune cell trafficking in the context of GSD1b. Taken together, our data indicates that that the immune impairment observed in GSD1b patients extends far beyond neutropenia and encompasses innate and adaptive compartments, which may provide novel insights into the pathogenesis of this disorder.

Regulation of T Cell Activation and Metabolism by Transforming Growth Factor-Beta

Transforming growth factor beta (TGFβ) receptor signalling regulates T cell development, differentiation and effector function. Expression of the immune-associated isoform of this cytokine, TGFβ1, is absolutely required for the maintenance of immunological tolerance in both mice and humans, whilst context-dependent TGFβ1 signalling regulates the differentiation of both anti- and pro-inflammatory T cell effector populations. Thus, distinct TGFβ-dependent T cell responses are implicated in the suppression or initiation of inflammatory and autoimmune diseases. In cancer settings, TGFβ signals contribute to the blockade of anti-tumour immune responses and disease progression. Given the key functions of TGFβ in the regulation of immune responses and the potential for therapeutic targeting of TGFβ-dependent pathways, the mechanisms underpinning these pleiotropic effects have been the subject of much investigation. This review focuses on accumulating evidence suggesting that modulation of T cell metabolism represents a major mechanism by which TGFβ influences T cell immunity.

Arming a killer: mitochondrial regulation of CD8+ T cell cytotoxicity

While once regarded as ATP factories, mitochondria have taken the spotlight as important regulators of cellular homeostasis. The past two decades have witnessed an intensifying interest in the study of mitochondria in cells of the immune system, with many new and unexpected roles for mitochondria emerging. Immune cells offer intriguing insights as mitochondria appear to play different roles at different stages of T cell development, matching the changing functions of the cells. Here we briefly review the multifaceted roles of mitochondria during T cell differentiation, focusing on CD8⁺ cytotoxic T lymphocytes (CTLs) and we consider how mitochondrial dysfunction can contribute to CTL exhaustion. In addition, we highlight a newly appreciated role for mitochondria as homeostatic regulators of CTL-mediated killing and explore the emerging literature describing mechanisms linking cytosolic and mitochondrial protein synthesis.

Altered Fatty Acid Oxidation in Lymphocyte Populations of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disabling multisystem illness in which individuals are plagued with fatigue, inflammatory symptoms, cognitive dysfunction, and the hallmark symptom, post-exertional malaise. While the cause of this disease remains unknown, there is evidence of a potential infectious component that, along with patient symptoms and common onsets of the disease, implicates immune system dysfunction. To further our understanding of the state of ME/CFS lymphocytes, we characterized the role of fatty acids in isolated Natural Killer cells, CD4+ T cells, and CD8+ T cells in circulation and after overnight stimulation, through implicit perturbations to fatty acid oxidation. We examined samples obtained from at least 8 and as many as 20 subjects for immune cell fatty acid characterization in a variety of experiments and found that all three isolated cell types increased their utilization of lipids and levels of pertinent proteins involved in this metabolic pathway in ME/CFS samples, particularly during higher energy demands and activation. In T cells, we characterized the cell populations contributing to these metabolic shifts, which included CD4+ memory cells, CD4+ effector cells, CD8+ naïve cells, and CD8+ memory cells. We also discovered that patients with ME/CFS and healthy control samples had significant correlations between measurements of CD4+ T cell fatty acid metabolism and demographic data. These findings provide support for metabolic dysfunction in ME/CFS immune cells. We further hypothesize about the consequences that these altered fuel dependencies may have on T and NK cell effector function, which may shed light on the illness's mechanism of action.

Modulating Immune Response in Viral Infection for Quantitative Forecasts of Drug Efficacy

The antiretroviral drug, the total level of viral production, and the effectiveness of immune responses are the main topics of this review because they are all dynamically interrelated. Immunological and viral processes interact in extremely complex and non-linear ways. For reliable analysis and quantitative forecasts that may be used to follow the immune system and create a disease profile for each patient, mathematical models are helpful in characterizing these non-linear interactions. To increase our ability to treat patients and identify individual differences in disease development, immune response profiling might be useful. Identifying which patients are moving from mild to severe disease would be more beneficial using immune system parameters. Prioritize treatments based on their inability to control the immune response and prevent T cell exhaustion. To increase treatment efficacy and spur additional research in this field, this review intends to provide examples of the effects of modelling immune response in viral infections, as well as the impact of pharmaceuticals on immune response.

TET Proteins in the Spotlight: Emerging Concepts of Epigenetic Regulation in T Cell Biology

Ten-eleven translocation (TET) proteins are dioxygenases that oxidize 5-methylcytosine to form 5-hydroxymethylcytosine and downstream oxidized modified cytosines. In the past decade, intensive research established that TET-mediated DNA demethylation is critical for immune cell development and function. In this study, we discuss major advances regarding the role of TET proteins in regulating gene expression in the context of T cell lineage specification, function, and proliferation. Then, we focus on open questions in the field. We discuss recent findings regarding the diverse roles of TET proteins in other systems, and we ask how these findings might relate to T cell biology. Finally, we ask how this tremendous progress on understanding the multifaceted roles of TET proteins in shaping T cell identity and function can be translated to improve outcomes of human disease, such as hematological malignancies and immune response to cancer.

Keeping T cell memories in mind

The mammalian central nervous system (CNS) contains a vibrant community of resident adaptive immune cells at homeostasis. Among these are memory CD8+ and CD4+ T cells, which reside in the CNS in the settings of health, aging, and neurological disease. These T cells commonly exhibit a tissue-resident memory (TRM) phenotype, suggesting that they are antigen-experienced and remain separate from the circulation. Despite these characterizations, T cell surveillance of the CNS has only recently been studied through the lens of TRM immunology. In this Review, we outline emerging concepts of CNS TRM generation, localization, maintenance, function, and specificity. In this way, we hope to highlight roles of CNS TRM in health and disease to inform future studies of adaptive neuroimmunity.

Serum Metabolic Correlates of the Antibody Response in Subjects Receiving the Inactivated COVID-19 Vaccine

BACKGROUND

Metabolites are involved in biological process that govern the immune response to infection and vaccination. Knowledge of how metabolites interact with the immune system during immunization with the COVID-19 vaccine is limited. Here, we report that the serum metabolites are correlated with the magnitude of the antibody response in recipients receiving the inactivated COVID-19 vaccine, which provides critical information for studying metabolism regarding the human immune response to vaccination.

METHODS

106 healthy volunteers without history of SARS-CoV-2 infection or vaccination were prospectively enrolled to receive the primary series of two doses of inactivated whole-virion SARS-CoV-2 vaccine. The serum samples were collected 2-4 weeks after the second dose. The magnitude of the anti-RBD antibody was quantified using surrogate virus neutralization tests. The profile of metabolites in serum was identified using untargeted metabolomics analysis.

RESULTS

The level of anti-RBD antibody 14-28 days after the second dose was significantly elevated and its interpersonal variability was diverse in a wide range. Thirty-two samples at extremes of the anti-RBD antibody titer were selected to discover the metabolic correlates. Two hundred and fifteen differential metabolites associated with antibody response independent of body mass index were identified. Pregnenolone and sphingolipid metabolism might be involved in the modulation of the human antibody response to the inactivated COVID-19 vaccine.

CONCLUSION

We discovered key metabolites as well as those with a related functional significance that might modulate the human immune response to vaccination.

Metabolic features of innate lymphoid cells

Innate and adaptive immune cells are found in distinct tissue niches where they orchestrate immune responses. This requires intrinsic and temporal metabolic adaptability to coordinately activate the immune response cascade. Dysregulation of this program is a key feature of immunosuppression. Direct or indirect metabolic immune cell reprogramming may offer new approaches to modulate immune cells behavior for therapy to overcome dysregulation. In this review, we explored how metabolism regulates lymphocytes beyond the classical T cell subsets. We focus on the innate lymphoid cell (ILC) family, highlighting the distinct metabolic characteristics of these cells, the impact of environmental factors, and the receptors that could alter immune cell functions through manipulation of metabolic pathways to potentially prevent or treat various diseases.

Elucidating the mitochondrial function of murine lymphocyte subsets and the heterogeneity of the mitophagy pathway inherited from hematopoietic stem cells

BACKGROUND

Mitochondria are mainly involved in ATP production to meet the energy demands of cells. Researchers are increasingly recognizing the important role of mitochondria in the differentiation and activation of hematopoietic cells, but research on how mitochondrial metabolism influence different subsets of lymphocyte at different stages of differentiation and activation are yet to be carried out. In this work, the mitochondrial functions of lymphocytes were compared at different differentiation and activation stages and included CD8+ T lymphocytes, CD4+ T lymphocytes, B lymphocytes, NK cells as well as their subsets. For this purpose, a complete set of methods was used to comprehensively analyze mitophagy levels, mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and the mitochondrial mass (MM) of subsets of lymphocytes. It is expected that this will provide a complete set of standards, and drawing the mitochondrial metabolic map of lymphocyte subsets at different stages of differentiation and activation.

RESULTS AND DISCUSSION

Of all lymphocytes, B cells had a relatively high mitochondrial metabolic activity which was evident from the higher levels of mitophagy, ROS, MMP and MM, and this reflected the highly heterogeneous nature of the mitochondrial metabolism in lymphocytes. Among the B cell subsets, pro-B cells had relatively higher levels of MM and MMP, while the mitochondrial metabolism level of mature B cells was relatively low. Similarly, among the subsets of CD4+ T cell, a relatively higher level of mitochondrial metabolism was noted for naive CD4+ T cells. Finally, from the CD8+ T cell subsets, CD8+ Tcm had relatively high levels of MM and MMP but relatively low ones for mitophagy, with effector T cells displaying the opposite characteristics. Meanwhile, the autophagy-related genes of lymphoid hematopoietic cells including hematopoietic stem cells, hematopoietic progenitor cells and lymphocyte subsets were analyzed, which preliminarily showed that these cells were heterogeneous in the selection of mitophagy related Pink1/Park2, BNIP3/NIX and FUNDC1 pathways. The results showed that compared with CD4+ T, CD8+ T and NK cells, B cells were more similar to long-term hematopoietic stem cell (LT-HSC) and short-term hematopoietic stem cell (ST-HSC) in terms of their participation in the Pink1/Park2 pathway, as well as the degree to which the characteristics of autophagy pathway were inherited from HSC. Compared with CLP and B cells, HSC are less involved in BNIP3/NIX pathway. Among the B cell subsets, pro-B cells inherited the least characteristics of HSC in participating in Pink1/Park2 pathway compared with pre-B, immature B and immature B cells. Among CD4+ T cell subsets, nTreg cells inherited the least characteristics of HSC in participating in Pink1/Park2 pathway compared with naive CD4+ T and memory CD4+ T cells. Among the CD8+ T cell subsets, compared with CLP and effector CD8+ T cells, CD8+ Tcm inherit the least characteristics of HSC in participating in Pink1/Park2 pathway. Meanwhile, CLP, naive CD4+ T and effector CD8+ T were more involved in BNIP3/NIX pathway than other lymphoid hematopoietic cells.

CONCLUSION

This study is expected to provide a complete set of methods and basic reference values for future studies on the mitochondrial functions of lymphocyte subsets at different stages of differentiation and activation in physiological state, and also provides a standard and reference for the study of infection and immunity based on mitochondrial metabolism.

A phase I/Ib trial and biological correlate analysis of neoadjuvant SBRT with single-dose durvalumab in HPV-unrelated locally advanced HNSCC

Five-year survival for human papilloma virus-unrelated head and neck squamous cell carcinomas remain below 50%. We assessed the safety of administering combination hypofractionated stereotactic body radiation therapy with single-dose durvalumab (anti-PD-L1) neoadjuvantly (n = 21) ( NCT03635164 ). The primary endpoint of the study was safety, which was met. Secondary endpoints included radiographic, pathologic and objective response; locoregional control; progression-free survival; and overall survival. Among evaluable patients at an early median follow-up of 16 months (448 d or 64 weeks), overall survival was 80.1% with 95% confidence interval (95% CI) (62.0%, 100.0%), locoregional control and progression-free survival were 75.8% with 95% CI (57.5%, 99.8%), and major pathological response or complete response was 75% with 95% exact CI (51.6%, 100.0%). For patients treated with 24 Gy, 89% with 95% CI (57.1%, 100.0%) had MPR or CR. Using high-dimensional multi-omics and spatial data as well as biological correlatives, we show that responders had: (1) an increase in effector T cells; (2) a decrease in immunosuppressive cells; and (3) an increase in antigen presentation post-treatment.

Fatty acid metabolism in T-cell function and differentiation

Immunometabolism has recently emerged as a field of study examining the intersection between immunology and metabolism. Studies in this area have yielded new findings on the roles of a diverse range of metabolic pathways and metabolites, which have been found to control many aspects of T-cell biology, including cell differentiation, function and fate. A particularly important finding has been the discovery that to meet the energy requirements associated with their proliferation, activation and specific functions, T cells switch their metabolic signatures during differentiation. For example, whereas the induction of de novo fatty acid biosynthesis and fatty acid uptake programs are required for antigen-stimulation-induced proliferation and differentiation of effector T cells, fatty acid catabolism via β-oxidation is essential for the generation of memory T cells and the differentiation of regulatory T cells. In this review, we discuss recent advances in our understanding of the metabolism in different stages of T cells and how fatty acid metabolism in these cells controls their specific functions.

The role of AMP-activated protein kinase in GVHD-causing T cells

Allogeneic stem cell transplantation is a curative therapy for multiple hematologic disorders. However, this life-saving procedure is often complicated by acute graft-versus-host disease (GVHD), where donor T cells attack tissues in the recipient's skin, liver, and gastrointestinal tract. Previous research has demonstrated that GVHD-causing T cells undergo significant metabolic reprogramming during disease pathogenesis, with an increased reliance on oxidative metabolism. This dependence makes metabolic modulation a potential approach to treat and/or prevent GVHD. Here, we provide an overview on the metabolic changes adopted by allogeneic T cells during disease initiation, highlighting the role played by AMP-activated protein kinase (AMPK) and identifying ways in which these insights might be leveraged to therapeutic advantage clinically.

Co-Stimulatory Receptor Signaling in CAR-T Cells

T cell engineering strategies have emerged as successful immunotherapeutic approaches for the treatment of human cancer. Chimeric Antigen Receptor T (CAR-T) cell therapy represents a prominent synthetic biology approach to re-direct the specificity of a patient's autologous T cells toward a desired tumor antigen. CAR-T therapy is currently FDA approved for the treatment of hematological malignancies, including subsets of B cell lymphoma, acute lymphoblastic leukemia (ALL) and multiple myeloma. Mechanistically, CAR-mediated recognition of a tumor antigen results in propagation of T cell activation signals, including a co-stimulatory signal, resulting in CAR-T cell activation, proliferation, evasion of apoptosis, and acquisition of effector functions. The importance of including a co-stimulatory domain in CARs was recognized following limited success of early iteration CAR-T cell designs lacking co-stimulation. Today, all CAR-T cells in clinical use contain either a CD28 or 4-1BB co-stimulatory domain. Preclinical investigations are exploring utility of including additional co-stimulatory molecules such as ICOS, OX40 and CD27 or various combinations of multiple co-stimulatory domains. Clinical and preclinical evidence implicates the co-stimulatory signal in several aspects of CAR-T cell therapy including response kinetics, persistence and durability, and toxicity profiles each of which impact the safety and anti-tumor efficacy of this immunotherapy. Herein we provide an overview of CAR-T cell co-stimulation by the prototypical receptors and discuss current and emerging strategies to modulate co-stimulatory signals to enhance CAR-T cell function.

Phenotypic, functional, and metabolic heterogeneity of immune cells infiltrating non–small cell lung cancer

Lung cancer is the leading cancer in the world, accounting for 1.2 million of new cases annually, being responsible for 17.8% of all cancer deaths. In particular, non–small cell lung cancer (NSCLC) is involved in approximately 85% of all lung cancers with a high lethality probably due to the asymptomatic evolution, leading patients to be diagnosed when the tumor has already spread to other organs. Despite the introduction of new therapies, which have improved the long-term survival of these patients, this disease is still not well cured and under controlled. Over the past two decades, single-cell technologies allowed to deeply profile both the phenotypic and metabolic aspects of the immune cells infiltrating the TME, thus fostering the identification of predictive biomarkers of prognosis and supporting the development of new therapeutic strategies. In this review, we discuss phenotypic and functional characteristics of the main subsets of tumor-infiltrating lymphocytes (TILs) and tumor-infiltrating myeloid cells (TIMs) that contribute to promote or suppress NSCLC development and progression. We also address two emerging aspects of TIL and TIM biology, i.e., their metabolism, which affects their effector functions, proliferation, and differentiation, and their capacity to interact with cancer stem cells.

A Novel Technique for the Generation of Substantial Numbers of Functional Resident T Cells from Kidney Tissue

Studying functionality and antigen-specificity of resident kidney T cells derived from a kidney biopsy is hampered by the lack of sufficient numbers of T cells obtained by the standard method of enzymatic tissue dissociation. Enzymatic dissociation of kidney tissue was compared to a novel method of whole kidney tissue culture allowing T cells to migrate into the medium in the presence of exogenous IL-2 and IL-15. T cell numbers were quantified and phenotype of resident T cells (CD69+CD103+/−), TCR Vβ repertoire and functional characteristics were analyzed with multi-parameter flow cytometry. Renal tissue culture for four weeks in the presence of exogenous IL-2 and IL-15 yielded significantly higher numbers of T cells (1.3 × 104/mm3) when compared to cultures without exogenous cytokines (71/mm3) or direct isolation by enzymatic dissociation (662/mm3 T cells, p < 0.05). The proportion of T cells with a resident phenotype did not change in the tissue culture; percentages amounted to 87.2% and 85.1%, respectively. In addition, frequencies of CD4+, CD8+, CD4−CD8−, T cells and MAIT T cells remained similar. For both CD4+ and CD8+, T cells had a more differentiated memory phenotype after tissue culture, but the distribution of TCR Vβ families did not change. In addition, the predominant Th1 cytokine secretion profile and poly-functionality of resident kidney T cell remained intact. T cell proliferation potential was not affected, excluding exhaustion and enrichment of BKV- and CMV-reactive resident T cells was observed. In conclusion, the kidney tissue culture method yields significantly increased numbers of resident T cells without major effects on composition and functionality.