Original ResearchVol. 41, Issue 6 • pp. 1041-1054DOI: 10.3969/j.issn.1000-4718.2025.06.001
Authors: RUAN Zhang, YANG Wenjing, YU Tianli, LI Pinxian, ZHANG Shunhui, LIN Caixia, ZHENG Lingyun, WANG Lijing
AIM: Regulatory T cells (Tregs) are a specialized subset of CD4+ T cells primarily involved in immunosuppressive functions. AMP-activated protein kinase (AMPK) serves as a metabolic sensor that governs the differentiation, maturation, and immune functions of Tregs through metabolic reprogramming. However, the impact of AMPKα1 (the catalytic subunit of AMPK) knockout specifically in Tregs on the host's immune microenvironment remains largely unexplored. METHODS: Histological changes in immune organs were assessed using HE staining. The types of immune cells and their relative population percentages in immune organs and blood were quantified through flow cytometry in both AMPKα1flox/flox (AMPKα1fl/fl) mice and Treg-specific AMPKα1 knockout mice (AMPKα1fl/flFoxp3cre mice). RESULTS: Compared to AMPKα1fl/fl mice, the percentage of eosinophils in the bone marrow of AMPKα1fl/flFoxp3cre mice was significantly reduced. Additionally, while the thymus of AMPKα1fl/flFoxp3cre mice exhibited normal structure, both its size and the ratio of thymus weight to body weight were significantly decreased. The knockout of AMPKα1 in Tregs led to a notable reduction in the total percentage of immature double-negative (DN) cells. Consequently, the percentage of CD4+ T cells derived from these DN cells also decreased, even though the percentages of DN1 and DN4 cells were higher in the thymus of AMPKα1fl/flFoxp3cre mice compared to AMPKα1fl/fl mice. Importantly, the proportion of Siglec-F+ CD11b+ eosinophils in the thymus was significantly lower in AMPKα1fl/flFoxp3cre mice. Knockout of AMPKα1 in Tregs resulted in a marked increase in the percentage of CD4+ T cells in peripheral blood, alongside a decrease in the proportion of mature CD8+ T cells. Similarly, the proportion of CD4+ T cells in the spleen of AMPKα1fl/flFoxp3cre mice was elevated compared to AMPKα1fl/fl mice. In contrast, the proportion of neutrophils significantly decreased, while mononuclear cell proportions increased in the spleen of AMPKα1fl/flFoxp3cre mice. In lymph nodes, the medullary boundaries in AMPKα1fl/flFoxp3cre mice were blurred, and the lymphoid follicles were missing, a feature not observed in AMPKα1fl/fl mice. Furthermore, the knockout of AMPKα1 in Tregs reduced the CD3+ T cell population, particularly the CD8+ T cell population, in lymph nodes. Although the mature Treg cell population was significantly lower in AMPKα1fl/flFoxp3cre mice, the percentage of CD4+ T cells was markedly increased. In contrast, there was no statistically significant difference in granulocyte populations between AMPKα1fl/flFoxp3cre and AMPKα1fl/fl mice. CONCLUSION: The populations of mature Tregs, CD8+ T cells and eosinophils in various immune organs were significantly altered in mice with Treg-specific AMPKα1 knockout, suggesting a potential remodeling of the host immune microenvironment in response to inflammatory stimuli.
