bims-imseme Biomed News
on Immunosenescence and T cell metabolism
Issue of 2024‒06‒16
twenty papers selected by
Pierpaolo Ginefra, Ludwig Institute for Cancer Research

  1. bioRxiv. 2024 Jun 01. pii: 2023.08.25.554830. [Epub ahead of print]
      The activation and functional differentiation of CD8 T cells are linked to metabolic pathways that result in the production of lactate. Lactylation is a lactate-derived histone post-translational modification (hPTM); however, the relevance of histone lactylation in the context of CD8 T cell activation and function is not known. Here, we show the enrichment of H3K18-lactylation (H3K18la) and H3K9-lactylation (H3K9la) in human and murine CD8 T cells which act as transcription initiators of key genes regulating CD8 T cell phenotype and function. Further, we note distinct impacts of H3K18la and H3K9la on CD8 T cell subsets linked to their specific metabolic profiles. Importantly, we demonstrate that modulation of H3K18la and H3K9la by targeting metabolic and epigenetic pathways regulates CD8 T cell effector function including anti-tumor immunity in preclinical models. Overall, our study uncovers the unique contributions of H3K18la and H3K9la in modulating CD8 T cell phenotype and function intricately associated with metabolic state.
  2. Nature. 2024 Jun 12.
      Obesity is a leading risk factor for progression and metastasis of many cancers1,2, yet can in some cases enhance survival3-5 and responses to immune checkpoint blockade therapies, including anti-PD-1, which targets PD-1 (encoded by PDCD1), an inhibitory receptor expressed on immune cells6-8. Although obesity promotes chronic inflammation, the role of the immune system in the obesity-cancer connection and immunotherapy remains unclear. It has been shown that in addition to T cells, macrophages can express PD-19-12. Here we found that obesity selectively induced PD-1 expression on tumour-associated macrophages (TAMs). Type I inflammatory cytokines and molecules linked to obesity, including interferon-γ, tumour necrosis factor, leptin, insulin and palmitate, induced macrophage PD-1 expression in an mTORC1- and glycolysis-dependent manner. PD-1 then provided negative feedback to TAMs that suppressed glycolysis, phagocytosis and T cell stimulatory potential. Conversely, PD-1 blockade increased the level of macrophage glycolysis, which was essential for PD-1 inhibition to augment TAM expression of CD86 and major histocompatibility complex I and II molecules and ability to activate T cells. Myeloid-specific PD-1 deficiency slowed tumour growth, enhanced TAM glycolysis and antigen-presentation capability, and led to increased CD8+ T cell activity with a reduced level of markers of exhaustion. These findings show that obesity-associated metabolic signalling and inflammatory cues cause TAMs to induce PD-1 expression, which then drives a TAM-specific feedback mechanism that impairs tumour immune surveillance. This may contribute to increased cancer risk yet improved response to PD-1 immunotherapy in obesity.
  3. Cell Metab. 2024 Jun 07. pii: S1550-4131(24)00190-6. [Epub ahead of print]
      Mitochondria house many metabolic pathways required for homeostasis and growth. To explore how human cells respond to mitochondrial dysfunction, we performed metabolomics in fibroblasts from patients with various mitochondrial disorders and cancer cells with electron transport chain (ETC) blockade. These analyses revealed extensive perturbations in purine metabolism, and stable isotope tracing demonstrated that ETC defects suppress de novo purine synthesis while enhancing purine salvage. In human lung cancer, tumors with markers of low oxidative mitochondrial metabolism exhibit enhanced expression of the salvage enzyme hypoxanthine phosphoribosyl transferase 1 (HPRT1) and high levels of the HPRT1 product inosine monophosphate. Mechanistically, ETC blockade activates the pentose phosphate pathway, providing phosphoribosyl diphosphate to drive purine salvage supplied by uptake of extracellular bases. Blocking HPRT1 sensitizes cancer cells to ETC inhibition. These findings demonstrate how cells remodel purine metabolism upon ETC blockade and uncover a new metabolic vulnerability in tumors with low respiration.
    Keywords:  HPRT1; NAD(+):NADH ratio; electron transport chain; metabolomics; purine metabolism; stable isotopes
  4. Science. 2024 Jun 14. 384(6701): eadj4301
      Mitochondria are critical for proper organ function and mechanisms to promote mitochondrial health during regeneration would benefit tissue homeostasis. We report that during liver regeneration, proliferation is suppressed in electron transport chain (ETC)-dysfunctional hepatocytes due to an inability to generate acetyl-CoA from peripheral fatty acids through mitochondrial β-oxidation. Alternative modes for acetyl-CoA production from pyruvate or acetate are suppressed in the setting of ETC dysfunction. This metabolic inflexibility forces a dependence on ETC-functional mitochondria and restoring acetyl-CoA production from pyruvate is sufficient to allow ETC-dysfunctional hepatocytes to proliferate. We propose that metabolic inflexibility within hepatocytes can be advantageous by limiting the expansion of ETC-dysfunctional cells.
  5. MedComm (2020). 2024 Jun;5(6): e572
      Tumor-infiltrating CD4+ T cells orchestrate the adaptive immune response through remarkable plasticity, and the expression patterns of exhaustion-related inhibitory receptors in these cells differ significantly from those of CD8+ T cells. Thus, a better understanding of the molecular basis of CD4+ T cell exhaustion and their responses to immune checkpoint blockade (ICB) is required. Here, we integrated multiomics approaches to define the phenotypic and molecular profiles of exhausted CD4+ T cells in oropharyngeal squamous cell carcinoma (OPSCC). Two distinct immune-promoting (Module 1) and immunosuppressive (Module 2) functional modules in tumor-infiltrating CD4+ T cells were identified, and both the immune-promoting function of Module 1 cells and immunosuppressive function of Module 2 cells were positively associated with their corresponding exhaustion states. Furthermore, the application of ICBs targeting effector CD4+ T cells in Module 1 (αPD-1) and Treg cells in Module 2 (αCTLA-4) in mouse models could help reinvigorate the effector function of Module 1-exhausted CD4+ T cells and reduce the immunosuppressive function of Module 2-exhausted CD4+ T cells, ultimately promoting OPSCC tumor regression. Taken together, our study provides a crucial cellular basis for the selection of optimal ICB in treating OPSCC.
    Keywords:  CD4‐positive T‐lymphocytes; T cell exhaustion; head and neck cancer; immune checkpoint inhibitors; tumor microenvironment
  6. Trends Cancer. 2024 Jun 08. pii: S2405-8033(24)00097-9. [Epub ahead of print]
      Chimeric antigen receptor (CAR) T cell therapy has emerged as a revolutionary treatment for hematological malignancies, but its adaptation to solid tumors is impeded by multiple challenges, particularly T cell dysfunction and exhaustion. The heterogeneity and inhospitableness of the solid tumor microenvironment (TME) contribute to diminished CAR T cell efficacy exhibited by reduced cytotoxicity, proliferation, cytokine secretion, and the upregulation of inhibitory receptors, similar to the phenotype of tumor-infiltrating lymphocytes (TILs). In this review, we highlight recent advances in T cell therapy for solid tumors, particularly brain cancer. Innovative strategies, including locoregional delivery and 'armoring' CAR T cells with cytokines such as interleukin (IL)-18, are under investigation to improve efficacy and safety. We also highlight emerging issues with toxicity management of CAR T cell adverse events. This review discusses the obstacles associated with CAR T cell therapy in the context of solid tumors and outlines current and future strategies to overcome these challenges.
    Keywords:  adoptive immunotherapy; chimeric antigen receptor; cytokine release syndrome
  7. Immunol Rev. 2024 Jun 14.
      Systemic lupus erythematosus is a complex autoimmune disease resulting from a dysregulation of the immune system that involves gut dysbiosis and an altered host cellular metabolism. This review highlights novel insights and expands on the interactions between the gut microbiome and the host immune metabolism in lupus. Pathobionts, invasive pathogens, and even commensal microbes, when in dysbiosis, can all trigger and modulate immune responses through metabolic reprogramming. Changes in the microbiota's global composition or individual taxa may trigger a cascade of metabolic changes in immune cells that may, in turn, reprogram their functions. Factors contributing to dysbiosis include changes in intestinal hypoxia, competition for glucose, and limited availability of essential nutrients, such as tryptophan and metal ions, all of which can be driven by host metabolism changes. Conversely, the accumulation of some host metabolites, such as itaconate, succinate, and free fatty acids, could further influence the microbial composition and immune responses. Overall, mounting evidence supports a bidirectional relationship between host immunometabolism and the microbiota in lupus pathogenesis.
    Keywords:  glucose; lupus; metabolism; microbiome; mitochondria; tryptophan
  8. bioRxiv. 2024 May 28. pii: 2024.05.27.596106. [Epub ahead of print]
      Metabolic adaptations in response to changes in energy supply and demand are essential for survival. The mitochondrial calcium uniporter coordinates metabolic homeostasis by regulating TCA cycle activation, mitochondrial fatty acid oxidation and cellular calcium signaling. However, a comprehensive analysis of uniporter-regulated mitochondrial metabolic pathways has remained unexplored. Here, we investigate the metabolic consequences of uniporter loss- and gain-of-function, and identify a key transcriptional regulator that mediates these effects. Using gene expression profiling and proteomic, we find that loss of uniporter function increases the expression of proteins in the branched-chain amino acid (BCAA) catabolism pathway. Activity is further augmented through phosphorylation of the enzyme that catalyzes this pathway's committed step. Conversely, in the liver cancer fibrolamellar carcinoma (FLC)-which we demonstrate to have high mitochondrial calcium levels- expression of BCAA catabolism enzymes is suppressed. We also observe uniporter-dependent suppression of the transcription factor KLF15, a master regulator of liver metabolic gene expression, including those involved in BCAA catabolism. Notably, loss of uniporter activity upregulates KLF15, along with its transcriptional target ornithine transcarbamylase (OTC), a component of the urea cycle, suggesting that uniporter hyperactivation may contribute to the hyperammonemia observed in FLC patients. Collectively, we establish that FLC has increased mitochondrial calcium levels, and identify an important role for mitochondrial calcium signaling in metabolic adaptation through the transcriptional regulation of metabolism.
  9. J Hepatocell Carcinoma. 2024 ;11 1031-1048
      Background: Layilin (LAYN) represents a valuable prognostic biomarker across various tumor types, while also serving as an innovative indicator of dysfunctional or exhausted CD8+ T cells and exhibiting correlation with immune context. However, the immune function and prognostic significance of LAYN in hepatocellular carcinoma (HCC) remain unexplored. Therefore, our objective is to investigate the role of LAYN in CD8+ T cell exhaustion, clinical prognosis, and the tumor microenvironment within HCC.Methods: TIMER or GEPIA databases were used to analyze LAYN expression level and its correlation with immune infiltration in HCC. Bioinformatics analysis was conducted on TCGA and scRNA-seq cohorts. The evaluation of LAYN expression level in fresh specimens was performed through IF, IHC, and ELISA assays. Flow cytometry and mRNA-seq were employed to investigate co-expressed genes of LAYN, the LAYN+CD8+ T cell exhaustion signature and immune function. Cell proliferation ability and killing activity were assessed using CCK8 and CFSE/PI.
    Results: The expression level of LAYN in HCC tumors was significantly higher compared to peri-tumors. Patients with high levels of LAYN exhibited poorer OS. GO or KEGG analysis confirmed that LAYN was involved in immune response and was positively associated with CD8+ T cell immune infiltration levels. Furthermore, LAYN negatively regulated the immune function of CD8+ T cells, leading to dysfunctional phenotypes characterized by elevated levels of CD39, TIM3 and reduced levels of perforin, TNF-α, Ki-67. CFSE/PI assays demonstrated that LAYN+CD8+ T cells displayed decreased cytotoxic activity. Additionally, there was a positive correlation between LAYN and CD146 levels, which are involved in adhesion and localization processes of CD8+ T cells. Interestingly, blocking LAYN partially restored the exhaustion properties of CD8+ T cells.
    Conclusion: LAYN exhibits a strong correlation with immune infiltration in the TME and represents a novel biomarker for predicting clinical prognosis in HCC. Moreover, targeting LAYN may hold promise as an effective strategy for HCC immunotherapy.
    Keywords:  CD8+ T cell exhaustion; hepatocellular carcinoma; layilin; prognosis
  10. Adv Sci (Weinh). 2024 Jun 14. e2403148
      Astaxanthin (ASX) is an oxygen-containing non-vitamin A carotenoid pigment. However, the role of ASX in autoimmune hepatitis (AIH) remains unclear. In this study, a mouse model of AIH is established induced by concanavalin A (ConA). Mass cytometry and single-cell RNA sequencing (scRNA-seq) are used to analyze the potential role of ASX in regulating the immune microenvironment of AIH. ASX treatment effectively alleviated liver damage induced by ConA and downregulated pro-inflammatory cytokines production in mice. Mass cytometry and scRNA-seq analyses revealed a significant increase in the number of CD8+ T cells following ASX treatment. Functional markers of CD8+ T cells, such as CD69, MHC II, and PD-1, are significantly downregulated. Additionally, specific CD8+ T cell subclusters (subclusters 4, 13, 24, and 27) are identified, each displaying distinct changes in marker gene expression after ASX treatment. This finding suggests a modulation of CD8+ T cell function by ASX. Finally, the key transcription factors for four subclusters of CD8+ T cells are predicted and constructed a cell-to-cell communication network based on receptor-ligand interactions probability. In conclusion, ASX holds the potential to ameliorate liver damage by regulating the number and function of CD8+ T cells.
    Keywords:  Astaxanthin; CD8+ T cell; autoimmune hepatitis; cytokine; immune microenvironment
  11. Cell Death Discov. 2024 Jun 13. 10(1): 283
      CD8+ T-cell exhaustion is a promising prognostic indicator of sepsis-induced acute respiratory distress syndrome (ARDS). Patients with sepsis-related ARDS had reduced levels of HSP90AA1. However, whether the changes in CD8+ T cells were related to HSP90α, encoded by the HSP90AA1 gene, was unclear. This study aimed to examine the regulatory mechanism of HSP90α and its impact on CD8+ T-cell exhaustion in lipopolysaccharide (LPS)-induced acute lung injury (ALI). In this study, by conducting a mouse model of ALI, we found that one week after LPS-induced ALI, CD8+ T cells showed exhaustion characteristics. At this time, proliferation and cytokine release in CD8+ T cells were reduced. The inhibitory costimulatory factors PD-1 and Tim-3, on the other hand, were enhanced. Meanwhile, the expression of HSP90α and STAT1 decreased significantly. The in vitro studies showed that HSP90α stimulation or inhibition affected the CD8+ T-cell exhaustion phenotype. Interference with STAT1 reduced the expression of HSP90α and impaired its regulation of CD8+ T cells. The Co-Immunoprecipitation results indicated that HSP90α can directly or indirectly bind to TOX to regulate TOX expression and downstream signal transduction. In summary, by inhibiting TOX-mediated exhaustion signaling pathways, HSP90α inhibited CD8+ T-cell exhaustion in ALI. The participation of STAT1 in the regulation of HSP90α was required.
  12. Front Aging. 2024 ;5 1389789
      No clear consensus has emerged from the literature on the gene expression changes that occur in human whole blood with age. In this study we compared whole blood ageing genes from the published literature with data on gene specificity for leukocyte subtypes. Surprisingly we found that highly ranked ageing genes were predominantly expressed by naïve T cells, with limited expression from more common cell types. Highly ranked ageing genes were also more likely to have decreased expression with age. Taken together, it is plausible that much of the observed gene expression changes in whole blood is reflecting the decline in abundance of naïve T cells known to occur with age, rather than changes in transcription rates in common cell types. Correct attribution of the gene expression changes that occur with age is essential for understanding the underlying mechanisms.
    Keywords:  ageing; ageing clocks; confounding variables; gene expression; leukocyte; naïve T cell; transcriptomics; whole blood
  13. Int Immunopharmacol. 2024 Jun 08. pii: S1567-5769(24)00962-7. [Epub ahead of print]137 112441
      Vaccination has become a widely used method to induce immune protection against microbial pathogens, including viral and bacterial microorganisms. Both humoral and cellular immunity serve a critical role in neutralizing and eliminating these pathogens. An effective vaccine should be able to induce a long-lasting immune memory response. Recent investigations on different subsets of T cells have identified a new subset of T cells using multi-parameter flow cytometry, which possess stem cell-like properties and the ability to mount a rapid immune response upon re-exposure to antigens known as stem cell-like memory T cells (TSCM). One of the major challenges with current vaccines is their limited ability to maintain long-term memory in the adaptive immune system. Recent evidence suggests that a specific subgroup of memory T cells has the unique ability to retain their longevity for up to 25 years, as observed in the case of the yellow fever vaccine. Therefore, in this study, we tried to explore and discuss the potential role of this new T cell memory subset in the development of viral and bacterial vaccines.
    Keywords:  Bacterial infection; T memory stem cell; Vaccine; Viral infection
  14. Trends Immunol. 2024 Jun 13. pii: S1471-4906(24)00120-0. [Epub ahead of print]
      Immunotherapies have revolutionized the treatment of certain cancers, but challenges remain in overcoming immunotherapy resistance. Research shows that metabolic modulation of the tumor microenvironment can enhance antitumor immunity. Here, we discuss recent preclinical and clinical evidence for the efficacy of combining metabolic modifiers with immunotherapies. While this combination holds great promise, a few key areas must be addressed, which include identifying the effects of metabolic modifiers on immune cell metabolism, the putative biomarkers of therapeutic efficacy, the efficacy of modifiers on tumors harboring metabolic heterogeneity, and the potential development of resistance due to tumor reliance on alternative metabolic pathways. We propose solutions to these problems and posit that assessing these parameters is crucial for considering the potential of metabolic modifiers in sensitizing tumors to immunotherapies.
    Keywords:  immunotherapy; immunotherapy resistance; metabolic reprogramming
  15. Inflamm Res. 2024 Jun 08.
      BACKGROUND: Uremia-associated immunodeficiency, mainly characterized by T cell dysfunction, exists in patients on maintenance hemodialysis (MHD) and promotes systemic inflammation. However, T cell senescence, one of the causes of T cell dysfunction, has not been clearly revealed yet. In this cross-sectional research, we aimed to study the manifestation of T cell premature senescence in MHD patients and further investigate the associated clinical factors.METHODS: 76 MHD patients including 33 patients with cardiovascular diseases (CVD) and 28 patients with arteriovenous fistula (AVF) event history were enrolled in this study. Complementarity determining region 3 (CDR3) of T cell receptor (TCR) was analyzed by immune repertoire sequencing (IR-Seq). CD28- T cell subsets and expression of senescence marker p16 and p21 genes were detected by multicolor flow cytometry and RT-qPCR, respectively.
    RESULTS: MHD patients had significantly decreased TCR diversity (P < 0.001), increased CDR3 clone proliferation (P = 0.001) and a left-skewed CDR3 length distribution. The proportion of CD4 + CD28- T cells increased in MHD patients (P = 0.014) and showed a negative correlation with TCR diversity (P = 0.001). p16 but not p21 expression in T cells was up-regulated in MHD patients (P = 0.039). Patients with CVD exhibited increased expression of p16 and p21 genes (P = 0.010 and 0.004, respectively), and patients with AVF events showed further TCR diversity and evenness reduction (P = 0.002 and 0.017, respectively) compared to patients without the comorbidities. Moreover, age, average convection volume, total cholesterol, high-density lipoprotein cholesterol and transferrin saturation were associated with TCR diversity or CD4 + CD28- T cell proportion (P < 0.05).
    CONCLUSIONS: MHD patients undergo T cell premature senescence characterized by significant TCR diversity reduction and repertoire skew, as well as accumulation of the CD4 + CD28- subset and up-regulation of p16 gene. Patients with CVD or AVF events show higher level of immunosenescence. Furthermore, T cell senescence in MHD patients is associated with blood cholesterol and uremic toxin retention, suggesting potential intervention strategies in the future.
    Keywords:  Hemodialysis; Immunosenescence; Inflammaging; Inflammation; T-cell receptor; T-lymphocytes
  16. Cell. 2024 Jun 09. pii: S0092-8674(24)00535-X. [Epub ahead of print]
      Defective host defenses later in life are associated with changes in immune cell activities, suggesting that age-specific considerations are needed in immunotherapy approaches. In this study, we found that PD-1 and CTLA4-based cancer immunotherapies are unable to eradicate tumors in elderly mice. This defect in anti-tumor activity correlated with two known age-associated immune defects: diminished abundance of systemic naive CD8+ T cells and weak migratory activities of dendritic cells (DCs). We identified a vaccine adjuvant, referred to as a DC hyperactivator, which corrects DC migratory defects in the elderly. Vaccines containing tumor antigens and DC hyperactivators induced T helper type 1 (TH1) CD4+ T cells with cytolytic activity that drive anti-tumor immunity in elderly mice. When administered early in life, DC hyperactivators were the only adjuvant identified that elicited anti-tumor CD4+ T cells that persisted into old age. These results raise the possibility of correcting age-associated immune defects through DC manipulation.
    Keywords:  PGPC; T cells; cancer; checkpoint inhibitor therapy; dendritic cells; elderly; hyperactivation; immunotherapy; innate immunity; tumor immunity; vaccine
  17. J Leukoc Biol. 2024 Jun 10. pii: qiae131. [Epub ahead of print]
    Keywords:  CD38; HIV; Metabolism; T cells