School of Medicine, University of Concepcion, Concepcion 4070409, Chile.
Molecular and Translational Immunology Laboratory, Department of Clinical Biochemistry and Immunology, Pharmacy Faculty, University of Concepcion, Concepcion 4070409, Chile.
Biomolecules. 2024 Jul 14;14(7):846. doi: 10.3390/biom14070846.
CD4+ T lymphocytes play a key role in the modulation of the immune response by orchestrating both effector and regulatory functions. The effect of metformin on the immunometabolism of CD4+ T lymphocytes has been scarcely studied, and its impact under high glucose conditions, particularly concerning effector responses and glucose metabolism, remains unknown. This study aims to evaluate the effect of metformin on the modulation of the effector functions and glucose metabolism of CD4+ T lymphocytes under normo- and hyperglycemic conditions. CD4+ T lymphocytes, obtained from peripheral blood from healthy volunteers, were anti-CD3/CD28-activated and cultured for 4 days with three concentrations of metformin (0.1 mM, 1 mM, and 5 mM) under normoglycemic (5.5 mM) and hyperglycemic (25 mM) conditions. Effector functions such as proliferation, cell count, cell cycle analysis, activation markers and cytokine secretion were analyzed by flow cytometry. Glucose uptake was determined using the 2-NBDG assay, and levels of glucose, lactate, and phosphofructokinase (PFK) activity were assessed by colorimetric assays. Metformin at 5 mM restrained the cell counts and proliferation of CD4+ T lymphocytes by arresting the cell cycle in the S/G2 phase at the beginning of the cell culture, without affecting cell activation, cytokine production, and glucose metabolism. In fact, CD69 expression and IL4 secretion by CD4+ T lymphocytes was higher in the presence of 5 mM than the untreated cells in both glucose conditions. Overall, metformin inhibited proliferation through mechanisms associated with cell cycle arrest, leading to an increase in the S/G2 phases at the expense of G1 in activated CD4+ T lymphocytes in normo- and hyperglycemic conditions. Despite the cell cycle arrest, activated CD4+ T lymphocytes remained metabolically, functionally, and phenotypically activated.
CD4+ T 淋巴细胞通过协调效应和调节功能在调节免疫反应中发挥关键作用。二甲双胍对 CD4+ T 淋巴细胞免疫代谢的影响尚未得到充分研究，其在高糖条件下的影响，特别是关于效应反应和葡萄糖代谢的影响仍不清楚。本研究旨在评估二甲双胍在正常和高血糖条件下对 CD4+ T 淋巴细胞效应功能和葡萄糖代谢的调节作用。从健康志愿者外周血中获得 CD4+ T 淋巴细胞，用抗 CD3/CD28 激活，并在正常血糖（5.5 mM）和高血糖（25 mM）条件下用三种浓度的二甲双胍（0.1 mM、1 mM 和 5 mM）培养 4 天。通过流式细胞术分析增殖、细胞计数、细胞周期分析、激活标志物和细胞因子分泌等效应功能。用 2-NBDG 测定法测定葡萄糖摄取，用比色法测定葡萄糖、乳酸和磷酸果糖激酶（PFK）活性水平。5 mM 的二甲双胍通过在细胞培养开始时将细胞周期阻滞在 S/G2 期来抑制 CD4+ T 淋巴细胞的细胞计数和增殖，而不影响细胞激活、细胞因子产生和葡萄糖代谢。事实上，在两种葡萄糖条件下，与未经处理的细胞相比，存在 5 mM 二甲双胍时 CD4+ T 淋巴细胞的 CD69 表达和 IL4 分泌更高。总体而言，二甲双胍通过与细胞周期阻滞相关的机制抑制增殖，导致在正常和高血糖条件下激活的 CD4+ T 淋巴细胞中 S/G2 期增加，而 G1 期减少。尽管存在细胞周期阻滞，但激活的 CD4+ T 淋巴细胞在代谢、功能和表型上仍然保持激活。
