N Nature Aging · Oct 17, 2025 Heme and iron toxicity in the aged spleen impairs T cell immunity through iron deprivation Mechanisms of T cell aging involve cell-intrinsic alterations and interactions with immune and stromal cells. Here we found that splenic T cells exhibit greater functional decline than lymph node T cells within the same aged mouse, prompting investigation into how the aged spleen contributes to T cell aging. Proteomic analysis revealed increased expression of heme detoxification in aged spleen-derived lymphocytes. Exposure to the heme- and iron-rich aged splenic microenvironment induced aging phenotypes in young T cells, including reduced proliferation and CD39 upregulation. T cells survived this hostile niche by maintaining a low labile iron pool, at least in part, via IRP2 downregulation to resist ferroptosis but failed to induce sufficient iron uptake for activation. Iron supplementation enhanced antigen-specific T cell responses in aged mice. This study identifies the aged spleen as a source of hemolytic signals that systemically impair T cell function, underscoring a trade-off between T cell survival and function and implicating iron metabolism in immune aging. Ageing Cytokines Lymphocytes Metabolism biology mouse experiments
N Nature Aging · Oct 08, 2025 The secreted metabolite sensor CtBP2 links metabolism to healthy lifespan Within each cell, metabolite-sensing factors respond to coordinate metabolic homeostasis. How metabolic homeostasis is regulated intercellularly and how this may become dysregulated with age, however, remains underexplored. Here we describe a system regulated by a metabolite sensor, CtBP2. CtBP2 is secreted via exosomes in response to reductive metabolism, which is suppressed by oxidative stress. Exosomal CtBP2 administration extends lifespan in aged mice and improves healthspan in particular by reducing frailty. Mechanistically, we identify activation of CYB5R3 and AMPK downstream of exosomal CtBP2. Consistently, serum CtBP2 levels decrease with age and are negatively associated with cardiovascular disease incidence in humans yet are elevated in individuals from families with a history of longevity. Together our findings define a CtBP2-mediated metabolic system with potential for future clinical applications. Ageing Endocrine system and metabolic diseases Metabolism Molecular biology biology mouse experiments
