bims-imseme Biomed News
on Immunosenescence and T cell metabolism
Issue of 2023–04–30
24 papers selected by
Pierpaolo Ginefra, Ludwig Institute for Cancer Research
  1. PSGL-1 attenuates early TCR signaling to suppress CD8+ T cell progenitor differentiation and elicit terminal CD8+ T cell exhaustion.
  2. Senescent T cells: Beneficial and detrimental roles.
  3. Defective N-glycosylation in tumor-infiltrating CD8+ T cells impairs IFN-γ-mediated effector function.
  4. CD8+ T cells in white matter aging.
  5. T cells proliferate beyond organismal lifespan.
  6. Mll1 pioneers histone H3K4me3 deposition and promotes formation of CD8 + T stem cell memory.
  7. Deficiency of angiopoietin-like 4 enhances CD8+ T cell bioactivity via metabolic reprogramming for impairing tumour progression.
  8. Telomere vesicle transfer protects T cells from senescence.
  9. Mitochondrial Dysfunction in CD4+ T Effector Memory RA+ Cells.
  10. Spurious intragenic transcription is a feature of mammalian cellular senescence and tissue aging.
  11. Regulatory Mechanisms and Reversal of CD8+T Cell Exhaustion: A Literature Review.
  12. Intrinsic STAT4 Expression Controls Effector CD4 T Cell Migration and Th17 Pathogenicity.
  13. Cellular Senescence is a Double-Edged Sword in Regulating Aged Immune Responses to Influenza.
  14. T cells are active players in neurodegeneration.
  15. Reduced numbers of naïve CD4 + T cells and an altered CD4/CD8 balance in depressed common variable immune deficiency (CVID) patients. Is thymosin-α1 a possible treatment?
  16. Mitochondrial fusion induced by transforming growth factor-β1 serves as a switch that governs the metabolic reprogramming during differentiation of regulatory T cells.
  17. Dietary protein shapes the profile and repertoire of intestinal CD4 + T cells.
  18. Targeting Mitochondrial Oxidative Stress as a Strategy to Treat Aging and Age-Related Diseases.
  19. Acidity promotes the differentiation of immunosuppressive regulatory T cells.
  20. Prioritizing exhausted T cell marker genes highlights immune subtypes in pan-cancer.
  21. Expression and function of CD51 on CD8 T cells as an immunomodulatory target.
  22. SRC2 controls CD4+ T cell activation via stimulating c-Myc-mediated upregulation of amino acid transporter Slc7a5.
  23. Mitochondrial carriers set the epigenetic age.
  24. Editorial: Nutrition and metabolic aging.
  1. Cell Rep. 2023 Apr 26. pii: S2211-1247(23)00447-3. [Epub ahead of print]42(5): 112436
    PSGL-1 attenuates early TCR signaling to suppress CD8+ T cell progenitor differentiation and elicit terminal CD8+ T cell exhaustion.
    Jennifer L Hope, Dennis C Otero, Eun-Ah Bae, Christopher J Stairiker, Ashley B Palete, Hannah A Faso, Michelle Lin, Monique L Henriquez, Sreeja Roy, Hyungseok Seo, Xue Lei, Eric S Wang, Savio Chow, Roberto Tinoco, Gregory A Daniels, Kevin Yip, Alexandre Rosa Campos, Jun Yin, Peter D Adams, Anjana Rao, Linda M Bradley.
      PSGL-1 (P-selectin glycoprotein-1) is a T cell-intrinsic checkpoint regulator of exhaustion with an unknown mechanism of action. Here, we show that PSGL-1 acts upstream of PD-1 and requires co-ligation with the T cell receptor (TCR) to attenuate activation of mouse and human CD8+ T cells and drive terminal T cell exhaustion. PSGL-1 directly restrains TCR signaling via Zap70 and maintains expression of the Zap70 inhibitor Sts-1. PSGL-1 deficiency empowers CD8+ T cells to respond to low-affinity TCR ligands and inhibit growth of PD-1-blockade-resistant melanoma by enabling tumor-infiltrating T cells to sustain an elevated metabolic gene signature supportive of increased glycolysis and glucose uptake to promote effector function. This outcome is coupled to an increased abundance of CD8+ T cell stem cell-like progenitors that maintain effector functions. Additionally, pharmacologic blockade of PSGL-1 curtails T cell exhaustion, indicating that PSGL-1 represents an immunotherapeutic target for PD-1-blockade-resistant tumors.
    Keywords:  CD8 T cells; CP: Immunology; T cell exhaustion; T cell metabolism; T cell signaling; chronic infection; melanoma; tumor immunity
    DOI:  https://doi.org/10.1016/j.celrep.2023.112436
  2. Immunol Rev. 2023 Apr 25.
    Senescent T cells: Beneficial and detrimental roles.
    Phatthamon Laphanuwat, Daniel Claudio Oliveira Gomes, Arne N Akbar.
      As the thymus involutes during aging, the T-cell pool has to be maintained by the periodic expansion of preexisting T cells during adulthood. A conundrum is that repeated episodes of activation and proliferation drive the differentiation of T cells toward replicative senescence, due to telomere erosion. This review discusses mechanisms that regulate the end-stage differentiation (senescence) of T cells. Although these cells, within both CD4 and CD8 compartments, lose proliferative activity after antigen-specific challenge, they acquire innate-like immune function. While this may confer broad immune protection during aging, these senescent T cells may also cause immunopathology, especially in the context of excessive inflammation in tissue microenvironments.
    Keywords:  T cell; TEMRA; aging; senescence; terminally differentiated cell
    DOI:  https://doi.org/10.1111/imr.13206
  3. Immunol Cell Biol. 2023 Apr 28.
    Defective N-glycosylation in tumor-infiltrating CD8+ T cells impairs IFN-γ-mediated effector function.
    Soyeon Kim, Hyungyu Min, Jinwoo Nah, Jinguk Jeong, Kyungsoo Park, Wooseob Kim, Youngjin Lee, Jieun Kim, Jungeun An, Rho Hyun Seong.
      T cell-mediated antitumor immunity is modulated, in part, by N-glycosylation. However, the interplay between N-glycosylation and the loss of effector function in exhausted T cells has not yet been fully investigated. Here, we delineated the impact of N-glycosylation on the exhaustion of tumor-infiltrating lymphocytes in a murine colon adenocarcinoma model, focusing on the IFN-γ-mediated immune response. We found that exhausted CD8+ T cells downregulated the oligosaccharyltransferase complex, which is indispensable for N-glycan transfer. Concordant N-glycosylation deficiency in tumor-infiltrating lymphocytes leads to loss of antitumor immunity. Complementing the oligosaccharyltransferase complex restored IFN-γ production and alleviated CD8+ T cell exhaustion, resulting in reduced tumor growth. Thus, aberrant glycosylation induced in the tumor microenvironment incapacitates effector CD8+ T cells. Our findings provide insights into CD8+ T cell exhaustion by incorporating N-glycosylation to understand the characteristic loss of IFN-γ, opening new opportunities to amend the glycosylation status in cancer immunotherapies.
    Keywords:  IFN-γ, N-glycosylation, T cell exhaustion, tumor immunology, tumor-infiltrating lymphocytes
    DOI:  https://doi.org/10.1111/imcb.12647
  4. Nat Aging. 2022 Dec;2(12): 1086
    CD8+ T cells in white matter aging.
    Caroline Barranco.
      
    DOI:  https://doi.org/10.1038/s43587-022-00334-5
  5. Nat Aging. 2023 Feb;3(2): 144
    T cells proliferate beyond organismal lifespan.
    Anna Kriebs.
      
    DOI:  https://doi.org/10.1038/s43587-023-00376-3
  6. bioRxiv. 2023 Apr 15. pii: 2023.01.18.524461. [Epub ahead of print]
    Mll1 pioneers histone H3K4me3 deposition and promotes formation of CD8 + T stem cell memory.
    Adam J Getzler, Megan A Frederick, Justin J Milner, Thomas Venables, Huitian Diao, Clara Toma, Shashank D Nagaraja, Dominic S Albao, Simon Bélanger, Shanel M Tsuda, Jihye Kim, Shane Crotty, Ananda W Goldrath, Matthew E Pipkin.
      CD8 + T cells with stem cell-like properties (T SCM ) sustain adaptive immunity to intracellular pathogens and tumors. However, the developmental origins and chromatin regulatory factors (CRFs) that establish their differentiation are unclear. Using an RNA interference screen of all CRFs we discovered the histone methylase Mll1 was required during T cell receptor (TCR) stimulation for development of a T SCM precursor state and mature memory (T MEM ) cells, but not short-lived or transitory effector cell-like states, in response to viral infections and tumors. Mll1 was essential for widespread de novo deposition of histone H3 lysine 4 trimethylation (H3K4me3) upon TCR stimulation, which accounted for 70% of all activation-induced sites in mature T MEM cells. Mll1 promoted both H3K4me3 deposition and reduced TCR-induced Pol II pausing at genes whose single-cell transcriptional dynamics explained trajectories into nascent T SCM precursor states during viral infection. Our results suggest Mll1-dependent control of Pol II elongation and H3K4me3 establishes and maintains differentiation of CD8 + T SCM cell states.
    DOI:  https://doi.org/10.1101/2023.01.18.524461
  7. Immunology. 2023 Apr 24.
    Deficiency of angiopoietin-like 4 enhances CD8+ T cell bioactivity via metabolic reprogramming for impairing tumour progression.
    Shizhen Ding, Zhijie Lin, Xiaoyuan Zhang, Xiaoqing Jia, Hualing Li, Yi Fu, Xuefeng Wang, Guoqiang Zhu, Guotao Lu, Weiming Xiao, Weijuan Gong.
      Angiopoietin-like 4 (ANGPTL4) is a secreted metabolism-modulating glycoprotein involved in the progression of tumours, cardiovascular diseases, metabolic syndrome and infectious diseases. In this study, more CD8+ T cells were activated to be effector T cells in ANGPTL4-/- mice. Impaired growth of tumours implanted in 3LL, B16BL6 or MC38 cells and reduced metastasis by B16F10 cells were observed in ANGPTL4-/- mice. Bone marrow (BM) transplantation experiments displayed that deficiency of ANGPTL4 in either host or BM cells promoted CD8+ T cell activation. However, ANGPTL4 deficiency in CD8+ T cells themselves showed more efficient anti-tumour activities. Recombinant ANGPTL4 protein promoted tumour growth in vivo with the less CD8+ T cell infiltration and it directly downregulated CD8+ T cell activation ex vivo. Transcriptome sequencing and metabolism analysis identified that ANGPTL4-/- CD8+ T cells increased glycolysis and decreased oxidative phosphorylation, which was dependent on the PKCζ-LKB1-AMPK-mTOR signalling axis. Reverse correlation of elevated ANGPTL4 levels in sera and tumour tissues with activated CD8+ T cells in the peripheral blood was displayed in patients with colorectal cancer. These results demonstrated that ANGPTL4 decreased immune surveillance in tumour progression by playing an immune-modulatory role on CD8+ T cells via metabolic reprogramming. Efficient blockade of ANGPTL4 expression in tumour patients would generate an effective anti-tumour effect mediated by CD8+ T cells.
    Keywords:  ANGPTL4; CD8; T cell; metabolism; tumour
    DOI:  https://doi.org/10.1111/imm.13650
  8. Nat Aging. 2022 Oct;2(10): 872
    Telomere vesicle transfer protects T cells from senescence.
    Yahyah Aman.
      
    DOI:  https://doi.org/10.1038/s43587-022-00296-8
  9. Biology (Basel). 2023 Apr 14. pii: 597. [Epub ahead of print]12(4):
    Mitochondrial Dysfunction in CD4+ T Effector Memory RA+ Cells.
    Marie Strickland, Salanne Lee, Shi Yong Neo, Akhila Balachander, Ivy Low, Seri Mustafah, Wah Ing Goh, Graham D Wright, Anis Larbi, Sylvia L F Pender.
      Human ageing is accompanied by poor responses to infection and decreased vaccine efficacy. While the causes of this can be attributed to defects in the immune system that increase with age, it is unknown whether mitochondrial dysfunction may also contribute to these phenomena. This study aims to assess mitochondrial dysfunction in CD4+ terminal effector memory T cells re-expressing CD45RA (TEMRA) cells and other CD4+ memory T cell subtypes, which are increased in number in the elderly population, with respect to how their metabolic responses to stimulation are altered compared to CD4+ naïve T cells. In this study, we show that CD4+ TEMRA cells exhibit altered mitochondrial dynamics compared to CD4+ naïve cells and CD4+ central and effector memory cells, with a 25% reduction in OPA1 expression. CD4+ TEMRA and memory cells show increased upregulation of Glucose transporter 1 following stimulation and higher levels of mitochondrial mass compared to CD4+ naïve T cells. Additionally, TEMRA cells exhibit a decrease in mitochondrial membrane potential compared to other CD4+ memory cell subsets by up to 50%. By comparing young to aged individuals, more significant mitochondria mass and lower membrane potential were observed in CD4+ TEMRA of young individuals. In conclusion, we suggest that CD4+ TEMRA cells may be impaired with respect to their metabolic response to stimulation, possibly contributing to impaired responses to infection and vaccination.
    Keywords:  T cells; flow cytometry; metabolism1; stimulation; terminally differentiated effector memory T cells (TEMRA)
    DOI:  https://doi.org/10.3390/biology12040597
  10. Nat Aging. 2023 Apr;3(4): 402-417
    Spurious intragenic transcription is a feature of mammalian cellular senescence and tissue aging.
    Payel Sen, Greg Donahue, Catherine Li, Gabor Egervari, Na Yang, Yemin Lan, Neil Robertson, Parisha P Shah, Erik Kerkhoven, David C Schultz, Peter D Adams, Shelley L Berger.
      Mammalian aging is characterized by the progressive loss of tissue function and increased risk for disease. Accumulation of senescent cells in aging tissues partly contributes to this decline, and targeted depletion of senescent cells in vivo ameliorates many age-related phenotypes. The fundamental molecular mechanisms responsible for the decline of cellular health and fitness during senescence and aging are largely unknown. In this study, we investigated whether chromatin-mediated loss of transcriptional fidelity, known to contribute to fitness and survival in yeast and worms, also occurs during human cellular senescence and mouse aging. Our findings reveal aberrant transcription initiation inside genes during senescence and aging that co-occurs with changes in the chromatin landscape. Interventions that alter these spurious transcripts have profound consequences on cellular health, primarily affecting intracellular signal transduction pathways. We propose that age-related spurious transcription promotes a noisy transcriptome and degradation of coherent transcriptional networks.
    DOI:  https://doi.org/10.1038/s43587-023-00384-3
  11. Biology (Basel). 2023 Apr 01. pii: 541. [Epub ahead of print]12(4):
    Regulatory Mechanisms and Reversal of CD8+T Cell Exhaustion: A Literature Review.
    Wanwan Zhu, Yiming Li, Mingwei Han, Jianli Jiang.
      CD8+T cell exhaustion is a state of T cell dysfunction during chronic infection and tumor progression. Exhausted CD8+T cells are characterized by low effector function, high expression of inhibitory receptors, unique metabolic patterns, and altered transcriptional profiles. Recently, advances in understanding and interfering with the regulatory mechanisms associated with T cell exhaustion in tumor immunotherapy have brought greater attention to the field. Therefore, we emphasize the typical features and related mechanisms of CD8+T cell exhaustion and particularly the potential for its reversal, which has clinical implications for immunotherapy.
    Keywords:  CD8+T cells; PD-1; exhaustion; immunotherapy; inhibitory receptors
    DOI:  https://doi.org/10.3390/biology12040541
  12. J Immunol. 2023 Apr 24. pii: ji2200606. [Epub ahead of print]
    Intrinsic STAT4 Expression Controls Effector CD4 T Cell Migration and Th17 Pathogenicity.
    Ashlyn A Buzzelli, Ian L McWilliams, Boyoung Shin, Morgan T Bryars, Laurie E Harrington.
      Effector CD4 T cells are central to the development of autoimmune chronic inflammatory diseases, yet factors that mediate pathogenicity remain ill-defined. Single-nucleotide polymorphisms in the human STAT4 locus are associated with susceptibility to multiple autoimmune disorders, and Stat4 is linked to the pathogenic Th17 gene signature; however, Th17 cells differentiate independently of STAT4. Hence the interplay between STAT4 and CD4 T cell function, especially Th17 cells, during autoimmune disease is unclear. In this article, we demonstrate that CD4 T cell-intrinsic STAT4 expression is essential for the induction of autoimmune CNS inflammation in mice, in part by regulating the migration of CD4 T cells to the inflamed CNS. Moreover, unbiased transcriptional profiling revealed that STAT4 controls the expression of >200 genes in Th17 cells and is important for the upregulation of genes associated with IL-23-stimulated, pathogenic Th17 cells. Importantly, we show that Th17 cells specifically require STAT4 to evoke autoimmune inflammation, highlighting, to our knowledge, a novel function for STAT4 in Th17 pathogenicity.
    DOI:  https://doi.org/10.4049/jimmunol.2200606
  13. bioRxiv. 2023 Apr 11. pii: 2023.04.10.536027. [Epub ahead of print]
    Cellular Senescence is a Double-Edged Sword in Regulating Aged Immune Responses to Influenza.
    Blake L Torrance, Hunter A Panier, Andreia N Cadar, Dominique E Martin, Erica C Lorenzo, Evan R Jellison, Jenna M Bartley, Laura Haynes.
      Clearance of senescent cells has demonstrated therapeutic potential in the context of chronic age-related diseases. Little is known, however, how clearing senescent cells affects the ability to respond to an acute infection and form quality immunological memory. We aimed to probe the effects of clearing senescent cells in aged mice on the immune response to influenza (flu) infection. We utilized a p16 trimodality reporter mouse model (p16-3MR) to allow for identification and selective deletion of p16-expressing senescent cells upon administration of ganciclovir (GCV). While p16-expressing senescent cells may exacerbate dysfunctional responses to a primary infection, our data suggest they may play a role in fostering memory cell generation. We demonstrate that although deletion of p16-expressing cells enhanced viral clearance, this also severely limited antibody production in the lungs of flu-infected aged mice. 30 days later, there were fewer flu-specific CD8 memory T cells and lower levels of flu-specific antibodies in the lungs of GCV treated mice. GCV treated mice were unable to mount an optimal memory response and demonstrated increased viral load following a heterosubtypic challenge. These results suggest that targeting senescent cells may potentiate primary responses while limiting the ability to form durable and protective immune memory with age.
    DOI:  https://doi.org/10.1101/2023.04.10.536027
  14. Nat Aging. 2023 Apr;3(4): 368
    T cells are active players in neurodegeneration.
    Hannah Walters.
      
    DOI:  https://doi.org/10.1038/s43587-023-00407-z
  15. Int Immunopharmacol. 2023 Apr 20. pii: S1567-5769(23)00489-7. [Epub ahead of print]119 110168
    Reduced numbers of naïve CD4 + T cells and an altered CD4/CD8 balance in depressed common variable immune deficiency (CVID) patients. Is thymosin-α1 a possible treatment?
    Olivia Manusama, Sajni Singh, Rik A Brooimans, Annemarie Wijkhuijs, Marianne van der Ent, Hemmo A Drexhage, Virgil A Dalm.
      In the 1990's the macrophage-T-cell-theory of depression was posed stating that low grade inflammation and an abnormal T cell system destabilize the development and function of the emotional brain in such a way, that individuals become ultrasensitive to stress. Recently we gathered evidence that indeed higher frequencies of CD4+ memory T cells, lower frequencies of naive CD4 + T cells, higher frequencies of CD8 + T cells (the latter two in part elicited by Cytomegalovirus, CMV, infection) are a characteristic of Major Depressive Disorder (MDD). In MDD patients with a history of childhood trauma and severe depression monocytes are inflammatory activated. Low grade inflammation and T cell system defects have also been reported in patients with Common Variable Immune Deficiency (CVID) (next to antibody production defects). CVID patients show a higher prevalence of mild depression. The aim of this study was to determine T cell frequencies and monocyte inflammatory activation in CVID patients with and without depression. This study confirms that CVID patients have CMV independent decreases in the frequency of naïve CD4 + T cells and it de novo shows a CMV dependent increase in the expression of inflammatory genes in monocytes. CVID patients with depression are additionally characterized by a CMV independent increase in the frequency of naïve CD8 + T cells, while lacking monocyte inflammatory activation. In conclusion, depressed CVID patients have T cell abnormalities comparable to that of patients with regular MDD. These abnormalities are presently targeted by thymosin α1 in an open-label proof of concept trial.
    Keywords:  CD4+ T cell; CD8+ T cell; Common Variable Immunodeficiency (CVID); Depressive mood; Thymalfasin
    DOI:  https://doi.org/10.1016/j.intimp.2023.110168
  16. Redox Biol. 2023 Apr 23. pii: S2213-2317(23)00110-6. [Epub ahead of print]62 102709
    Mitochondrial fusion induced by transforming growth factor-β1 serves as a switch that governs the metabolic reprogramming during differentiation of regulatory T cells.
    Yulai Fang, Qin Zhang, Changjun Lv, Yilei Guo, Yue He, Pengxiang Guo, Zhifeng Wei, Yufeng Xia, Yue Dai.
      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.
    Keywords:  Differentiation; Metabolic reprogramming; Mitochondrial fusion; TGF-β1; Treg cells
    DOI:  https://doi.org/10.1016/j.redox.2023.102709
  17. bioRxiv. 2023 Apr 13. pii: 2023.04.11.536475. [Epub ahead of print]
    Dietary protein shapes the profile and repertoire of intestinal CD4 + T cells.
    Ainsley Lockhart, Aubrey Reed, Tiago Rezende de Castro, Calvin Herman, Maria Cecilia Campos Canesso, Daniel Mucida.
      The intestinal immune system must tolerate food antigens to avoid allergy, a process requiring CD4 + T cells. Combining antigenically defined diets with gnotobiotic models, we show that food and microbiota distinctly influence the profile and T cell receptor repertoire of intestinal CD4 + T cells. Independent of the microbiota, dietary proteins contributed to accumulation and clonal selection of antigen-experienced CD4 + T cells at the intestinal epithelium, imprinting a tissue specialized transcriptional program including cytotoxic genes on both conventional and regulatory CD4 + T cells (Tregs). This steady state CD4 + T cell response to food was disrupted by inflammatory challenge, and protection against food allergy in this context was associated with Treg clonal expansion and decreased pro-inflammatory gene expression. Finally, we identified both steady state epithelium-adapted CD4 + T cells and tolerance-induced Tregs that recognize dietary antigens, suggesting that both cell types may be critical for preventing inappropriate immune responses to food.
    DOI:  https://doi.org/10.1101/2023.04.11.536475
  18. Antioxidants (Basel). 2023 Apr 15. pii: 934. [Epub ahead of print]12(4):
    Targeting Mitochondrial Oxidative Stress as a Strategy to Treat Aging and Age-Related Diseases.
    Yun Haeng Lee, Myeong Uk Kuk, Moon Kyoung So, Eun Seon Song, Haneur Lee, Soon Kil Ahn, Hyung Wook Kwon, Joon Tae Park, Sang Chul Park.
      Mitochondria are one of the organelles undergoing rapid alteration during the senescence process. Senescent cells show an increase in mitochondrial size, which is attributed to the accumulation of defective mitochondria, which causes mitochondrial oxidative stress. Defective mitochondria are also targets of mitochondrial oxidative stress, and the vicious cycle between defective mitochondria and mitochondrial oxidative stress contributes to the onset and development of aging and age-related diseases. Based on the findings, strategies to reduce mitochondrial oxidative stress have been suggested for the effective treatment of aging and age-related diseases. In this article, we discuss mitochondrial alterations and the consequent increase in mitochondrial oxidative stress. Then, the causal role of mitochondrial oxidative stress on aging is investigated by examining how aging and age-related diseases are exacerbated by induced stress. Furthermore, we assess the importance of targeting mitochondrial oxidative stress for the regulation of aging and suggest different therapeutic strategies to reduce mitochondrial oxidative stress. Therefore, this review will not only shed light on a new perspective on the role of mitochondrial oxidative stress in aging but also provide effective therapeutic strategies for the treatment of aging and age-related diseases through the regulation of mitochondrial oxidative stress.
    Keywords:  ROS; aging control; mitochondria; mitochondrial oxidative stress
    DOI:  https://doi.org/10.3390/antiox12040934
  19. Eur J Immunol. 2023 Apr 25. e2350511
    Acidity promotes the differentiation of immunosuppressive regulatory T cells.
    Karoliina Tuomela, Megan K Levings.
      The metabolic milieu is emerging as a major contributing factor in the maintenance of the immunosuppressive microenvironment within tumours. In particular, the presence of lactic acid produced by highly glycolytic cancer cells is known to suppress antitumour immune cell subsets while promoting immunosuppressive cell populations, such as regulatory T cells (Tregs). Unlike conventional T cells, Tregs have a uniquely potent ability to take up lactic acid to fuel both mitochondrial metabolism and gluconeogenesis, supporting suppressive function and proliferation. In this issue of the European Journal of [Immunology [Eur. J. Immunol. 2023.53:2250258], Rao et al. uncover a novel mechanism by which lactic acid can support Treg accumulation within tumours in mice. This study shows that lactic acid, through a pH-dependent mechanism rather than lactate itself, promotes TGFβ-induced differentiation of Tregs from conventional CD4+ T cells. These findings build on the already multifaceted role of lactic acid in maintaining an immunosuppressive tumour microenvironment. This article is protected by copyright. All rights reserved.
    Keywords:  Lactic acid; Regulatory T cells; Treg metabolism; immunosuppressive microenvironment
    DOI:  https://doi.org/10.1002/eji.202350511
  20. iScience. 2023 Apr 21. 26(4): 106484
    Prioritizing exhausted T cell marker genes highlights immune subtypes in pan-cancer.
    Chunlong Zhang, Qi Sheng, Xue Zhang, Kang Xu, Xiaoyan Jin, Weiwei Zhou, Mengying Zhang, Dezhong Lv, Changbo Yang, Yongsheng Li, Juan Xu, Xia Li.
      Exhausted T (TEX) cells are main immunotherapy targets in cancer, but it lacks a general identification method to characterize TEX cell in disease. To assess the characterization of TEX cell, we extract signature of TEX cell from large cancer and chronic infection cohorts. Based on single-cell transcriptomes, a systematic T cell exhaustion prediction (TEXP) model is designed to define TEX cell in cancer and chronic infection. We then prioritize 42 marker genes, including HAVCR2, PDCD1, TOX, TIGIT and LAG3, which are associated with T cell exhaustion. TEXP could identify high TEX and low TEX subtypes in pan-cancer of TCGA. The high TEX subtypes are characterized by high immune score, immune cell infiltration, high expression of TEX marker genes and poor prognosis. In summary, TEXP and marker genes provide a resource for understanding the function of TEX cell, with implications for immune prediction and immunotherapy in chronic infection and cancer.
    Keywords:  Bioinformatics; Cancer; Immunology; Transcriptomics
    DOI:  https://doi.org/10.1016/j.isci.2023.106484
  21. Biochem Biophys Res Commun. 2023 Apr 16. pii: S0006-291X(23)00449-7. [Epub ahead of print]661 56-63
    Expression and function of CD51 on CD8 T cells as an immunomodulatory target.
    Solhwi Lee, Junhui Ma, Se Jin Im.
      T cell responses are regulated by co-stimulatory and inhibitory receptors along with T cell receptor- and cytokine-mediated signals. CD51 is a transmembrane glycoprotein of the integrin family that plays a role in cell adhesion, migration, tumorigenesis, and other cellular functions. In this study, we aimed to investigate the expression and function of CD51 on CD8 T cells. Upon in vitro T cell activation, CD51 expression was delayed but subsequently was upregulated in CD8 T cells upon cell division. Furthermore, CD51 was highly expressed in exhausted CD8 T cells in chronic LCMV infection, B16F10 melanoma, and CT26 colon carcinoma, and its expression level increased as cells became more differentiated. Using CRISPR-mediated knockdown, we found that the absence of CD51 led to a lower number of virus-specific CD8 T cells upon chronic lymphocytic choriomeningitis virus (LCMV) infection, although their granzyme B expression and cytokine production were maintained. Blocking CD51 also inhibited the in vitro proliferation of CD8 T cells. These results suggest that CD51 plays an important role in the early expansion of CD8 T cells and may have potential as an immunomodulatory target.
    Keywords:  CD51; CD8 T cells; ITGAV; Immunomodulatory protein; T cell proliferation
    DOI:  https://doi.org/10.1016/j.bbrc.2023.04.040
  22. Proc Natl Acad Sci U S A. 2023 May 02. 120(18): e2221352120
    SRC2 controls CD4+ T cell activation via stimulating c-Myc-mediated upregulation of amino acid transporter Slc7a5.
    Wencan Zhang, Xu Cao, Xiancai Zhong, Hongmin Wu, Yun Shi, Mingye Feng, Yi-Chang Wang, David Ann, Yousang Gwack, Yate-Ching Yuan, Weirong Shang, Zuoming Sun.
      T cell activation stimulates substantially increased protein synthesis activity to accumulate sufficient biomass for cell proliferation. The protein synthesis is fueled by the amino acids transported from the environment. Steroid nuclear receptor coactivator 2 (SRC2) is a member of a family of transcription coactivators. Here, we show that SRC2 recruited by c-Myc enhances CD4+ T cell activation to stimulate immune responses via upregulation of amino acid transporter Slc7a5. Mice deficient of SRC2 in T cells (SRC2fl/fl/CD4Cre) are resistant to the induction of experimental autoimmune encephalomyelitis (EAE) and susceptible to Citrobacter rodentium (C. rodentium) infection. Adoptive transfer of naive CD4+ T cells from SRC2fl/fl/CD4Cre mice fails to elicit EAE and colitis in Rag1/ recipients. Further, CD4+ T cells from SRC2fl/fl/CD4Cre mice display defective T cell proliferation, cytokine production, and differentiation both in vitro and in vivo. Mechanically, SRC2 functions as a coactivator to work together with c-Myc to stimulate the expression of amino acid transporter Slc7a5 required for T cell activation. Slc7a5 fails to be up-regulated in CD4+ T cells from SRC2fl/fl/CD4Cre mice, and forced expression of Slc7a5 rescues proliferation, cytokine production, and the ability of SRC2fl/fl/CD4Cre CD4+ T cells to induce EAE. Therefore, SRC2 is essential for CD4+ T cell activation and, thus, a potential drug target for controlling CD4+ T cell-mediated autoimmunity.
    Keywords:  CD4+ T cell; T cell activation; autoimmunity; c-Myc
    DOI:  https://doi.org/10.1073/pnas.2221352120
  23. Nat Aging. 2021 Sep;1(9): 755-756
    Mitochondrial carriers set the epigenetic age.
    Carina Groh, Johannes M Herrmann.
      
    DOI:  https://doi.org/10.1038/s43587-021-00111-w
  24. Front Nutr. 2023 ;10 1191958
    Editorial: Nutrition and metabolic aging.
    Devin Wahl, Zachary S Clayton.
      
    Keywords:  aging; calorie restriction; health span; metabolic health; nutrition
    DOI:  https://doi.org/10.3389/fnut.2023.1191958
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