Ferroptosis Mediated by the IDO1/Kyn/AhR Pathway Triggers Acute Thymic Involution in Sepsis
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PROVIDER: PRJNA1179952 | ENA |
REPOSITORIES: ENA
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Project description:Sepsis triggers a systemic inflammatory response that leads to immune dysregulation and widespread organ damage. Acute thymic involution (ATI), a hallmark of sepsis, is characterized by decreased T cell production and weakened immune responses. The mechanism of ATI is not fully understood. In this study, we demonstrate that ferroptosis, an iron-dependent form of regulated cell death, plays a pivotal role in ATI during sepsis. Using a polymicrobial sepsis model, we observed significant ferroptosis-associated thymic damage, which was marked by lipid peroxidation, mitochondrial dysfunction, and a reduction in thymic size and cellularity. Treatment with 1-methyltryptophan (1-MT), an inhibitor of indoleamine 2,3-dioxygenase 1 (IDO1), effectively reversed these phenotypes, restoring thymic structure and function, and significantly improved survival outcomes in septic mice. Further mechanistic analysis revealed that IDO1 upregulation led to the accumulation of kynurenine, which activates the aryl hydrocarbon receptor (AhR), thereby driving ferroptosis in thymocytes. Our findings uncover a novel role for the IDO1/Kyn/AhR pathway in ferroptosis and suggest that targeting this pathway could be a promising therapeutic strategy for restoring thymic function and improving outcomes in sepsis.
2025-07-30 | GSE280678 | GEO
Project description:Given its central role in immune aging, identifying regulators of thymic involution is important. While conventional programmed cell death plays a fundamental role in thymocyte development, how cell death pathways contribute to thymic involution remains unclear. In this study, we found that CD4+CD8+ double positive (DP) thymocytes acquired characteristics of senescence in aged mice undergoing thymic involution, while expression of the m6A methyltransferase METTL3 (enriched in DP cells from young mice) decreased with aging. By conditionally deleting METTL3 in T cells, we revealed a critical role for METTL3 in DP cell survival, and in restraining features of aging in DP thymocytes by preventing ferroptosis signaling, through glutathione peroxidase 4 (GPX4). Mechanistically, GPX4 was maintained by METTL3 at the translational level, independent of its methyltransferase activity. Furthermore, we found that pharmacological inhibition of ferroptosis promoted DP cell survival, and attenuate d features of aging in DP thymocytes. These findings uncover a role for METTL3-regulated ferroptosis in thymic involution, and identify strategies to restore thymic function.
2024-08-18 | GSE271324 | GEO
Project description:Thymic involution is a crucial factor in immune system aging and results in age-related impairment of T cell responses. The control of programmed cell death plays a fundamental role in thymocytes development. How thymocytes cell death contribute to thymic involution remains elusive. In this study, we found that METTL3 is highly expressed in double positive (DP) cells from young mice but decreased in aged mice. Mice conditionally deficiency for METTL3 in T cells showed thymic involution phenotypes with decreased survival and increased senescent DP cells. Additionally, METTL3 deficiency elicited ferroptosis program rather than other cell death pathways and led to defective DP cell development. Furthermore, GPX4, a molecule that protects cells from ferroptosis, was essential for thymocyte survival and preventing senescence. Mechanistically, GPX4 was maintained by METTL3 at the translation level in METTL3 methyltransferase activity independent manner. Targeting METTL3 and ferroptosis process promoted DP cell survival and reinvigorated aged DP cells. These findings reveal the central role of the METTL3-GPX4-ferroptosis axis in regulating thymocyte homeostasis and identifying targets for impeding age-related thymic involution and diseases.
2025-03-01 | GSE243187 | GEO
Project description:METTL3 governs thymocyte development and thymic involution by regulating ferroptosis
| PRJNA1130936 | ENA
Project description:The thymus is the site of T lymphocyte development and T cell education to recognize foreign, but not self, antigens. B cells also reside and develop in the thymus, although their function(s) are less clear. During ‘thymic involution,’ a process of lymphoid atrophy and adipose replacement linked to sexual maturation, thymic cells decline. However, thymic B cells decrease far less than T cells, such that B cells comprise ~1% of neonatal thymocytes, but up to ~10% in adulthood in humans. All jawed vertebrates possess a thymus, and we and others have shown that zebrafish (Danio rerio) also have thymic B cells. Here, we investigated the precise identities of zebrafish thymic T and B cells and how they change with involution. We assessed the timing and specific details of zebrafish thymic involution using multiple lymphocyte-specific, fluorophore-labeled transgenic lines, quantifying changes in thymic lymphocytes pre- vs. post-involution. Our results prove that, as in humans, zebrafish thymic B cells increase relative to T cells post-involution. We also performed RNA sequencing (RNA-seq) on D. rerio thymic and marrow lymphocytes of four novel double-transgenic lines, identifying distinct populations of immature T and B cells. Collectively, this is the first comprehensive analysis of zebrafish thymic involution, demonstrating its similarity to human involution, and establishing the highly genetically-manipulatable zebrafish model as a template for involution studies.
2024-04-02 | GSE237139 | GEO
Project description:Adipocyte deposition is believed to be a primary characteristic of age-related thymic involution, but the underlying cellular and molecular mechanisms remain unknown. We show here that thymic mesenchymal stromal cells (tMSCs) have a higher tendency to differentiate into adipocytes and melanocortin-2 receptor accessory protein (MRAP) is a potential driver of tMSCs adipogenesis. Furthermore, we discover that thymosin-α1 promotes MRAP expression in tMSCs through FoxO1 signaling pathway. Additionally, the proportion of tMSCs increase in older mice compared to young mice. Importantly, MRAP is also necessary for human thymic MSCs to differentiate into adipocytes when exposed to thymosin-α1. Single-cell RNA-seq analysis of human thymus revealed an accumulation of tMSCs and adipocytes during aging, indicating a strong potential for adipogenic differentiation in age-related thymic involution. Thus, we have revealed MRAP as a key factor in promoting thymic MSCs adipogenesis triggered by thymosin-α1 and FoxO1 pathway, which may serve as potential target to hinder adiposity in age-related thymic involution.
2024-11-27 | GSE183261 | GEO
Project description:Transcriptome analysis was performed on the thymus of necropsied Japanese Black calves with a poor prognosis, to clarify the pathology of acute thymic involution, which often happens in farmed calves with a poor prognosis. Gene expression profiles obtained by DNA microarray analysis of eight calf thymuses were grouped into three patterns associated with the histopathological classification of acute thymic involution. Three clusters were arranged by the stage of acute thymic involution based on the first principal component score, suggesting that histopathological conditions have the most significant impact on changes in gene expression profile.
2024-08-18 | GSE269843 | GEO
Project description:While immunotherapy has shown efficacy in non-small cell lung cancer (NSCLC) patients, many respond only partially or not at all. One limitation in improving outcomes is the lack of a complete understanding of factors regulating immune checkpoint targets. Here, we sought to address a possible link between an environmental chemical receptor implicated in NSCLC and immune regulation, the aryl hydrocarbon receptor (AhR), and a known but counterintuitive mediator of immunosuppression, IFN , in regulation of two immune checkpoints, PD-L1 and the IDO1, in lung adenocarcinoma (LUAD). To this end we used AhR, PD-L1, and IFN R gene-edited LUAD cell lines, a syngeneic LUAD mouse model, bulk- and single cell-RNA sequencing of LUADs and tumor-infiltrating leukocytes, and existing human transcriptomic databases. The data demonstrate that: 1) the AhR regulates both PD-L1 and IDO1 in murine and human LUAD cells, 2) AhR-driven IDO1 results in production of Kyn which likely mediates an AhR→IDO1→Kyn→AhR amplification loop, 3) the previously characterized induction by IFN of PD-L1 and IDO is mediated by the AhR, 4) transplantation of LUAD cells in which the AhR is deleted results in long-term tumor immunity in approximately half of the mice; slow growing tumors in the other half exhibit significantly higher densities of CD4+ and CD8+ T cells expressing immunocompetence markers, and 5) deletion of either IFN R1 or PD-L1 does not provide the same level of immune protection as AhR deletion. The data definitively link IFN - mediated immunosuppression to the AhR and support the targeting of the AhR in the context of LUAD.
2024-06-08 | GSE241979 | GEO
Project description:While immunotherapy has shown efficacy in non-small cell lung cancer (NSCLC) patients, many respond only partially or not at all. One limitation in improving outcomes is the lack of a complete understanding of factors regulating immune checkpoint targets. Here, we sought to address a possible link between an environmental chemical receptor implicated in NSCLC and immune regulation, the aryl hydrocarbon receptor (AhR), and a known but counterintuitive mediator of immunosuppression, IFN , in regulation of two immune checkpoints, PD-L1 and the IDO1, in lung adenocarcinoma (LUAD). To this end we used AhR, PD-L1, and IFN R gene-edited LUAD cell lines, a syngeneic LUAD mouse model, bulk- and single cell-RNA sequencing of LUADs and tumor-infiltrating leukocytes, and existing human transcriptomic databases. The data demonstrate that: 1) the AhR regulates both PD-L1 and IDO1 in murine and human LUAD cells, 2) AhR-driven IDO1 results in production of Kyn which likely mediates an AhR→IDO1→Kyn→AhR amplification loop, 3) the previously characterized induction by IFN of PD-L1 and IDO is mediated by the AhR, 4) transplantation of LUAD cells in which the AhR is deleted results in long-term tumor immunity in approximately half of the mice; slow growing tumors in the other half exhibit significantly higher densities of CD4+ and CD8+ T cells expressing immunocompetence markers, and 5) deletion of either IFN R1 or PD-L1 does not provide the same level of immune protection as AhR deletion. The data definitively link IFN - mediated immunosuppression to the AhR and support the targeting of the AhR in the context of LUAD.
2024-06-08 | GSE241978 | GEO
Project description:The thymic microenvironment is essential for proper differentiation and selection of thymocytes.Thymic involution in aged mice results in decreased T cell output and immune function. Here we use gene expression profiling of FACS sorted thymic stromal subsets to identify molecular mediators of thymocyte: stromal cell interactions, as well as gene expression changes thymic stromal subsets during early stages of thymic involution . We used microarrays to analyze gene expression differences between thymic stromal subsets from male C57BL/6J mice 1, 3, and 6 months of age.
2014-09-12 | GSE56928 | GEO