Natural regulatory T cells (nTregs) play a dominant role in maintaining immunological homeostasis and they are known to undergo metabolic reprogramming during immune responses. Transforming growth factor-β1 (TGF-β1), an anti-inflammatory cytokine, can promote the induction of regulatory T cells. Here, we investigated the effects of TGF-β1 on the stability and metabolism of nTregs stimulated in vitro. CD4⁺CD25⁺ nTregs were isolated from mouse spleens and stimulated with anti-CD3 and anti-CD28 antibodies plus IL-2 in the presence or absence of TGF-β1. Exposure to TGF-β1 induced the activation of STAT5 and sustained the expression of the nTregs transcription factor Foxp3. In addition, TGF-β1 inhibited glycolysis, as shown by reduced lactate production and diminished expression of Glut1, Hk2, Enolase1, and Hif-1α. nTregs treated with TGF-β1 exhibited downregulated mTORC1 signaling but enhanced activation of the serine-threonine phosphatase PP2A. Moreover, treat with the PP2A inhibitor okadaic acid disrupted the maintenance of Foxp3 expression by TGF-β1. Thus, TGF-β1 serves to maintain Foxp3 expression in cultured nTregs, possibly via PP2A activation and suppression of mTORC1-regulated glycolysis.

天然调节性T细胞（nTregs）在维持免疫稳态方面起着主要作用，并且已知它们在免疫反应过程中会进行代谢重编程。抗炎细胞因子转化生长因子-β1（TGF-β1）可以促进调节性T细胞的诱导。在这里，我们研究了TGF-β1对体外刺激的nTregs稳定性和代谢的影响。CD4 ⁺ CD25 ⁺从小鼠脾脏中分离nTreg，并在存在或不存在TGF-β1的情况下，用抗CD3和抗CD28抗体以及IL-2进行刺激。暴露于TGF-β1诱导STAT5激活并维持nTregs转录因子Foxp3的表达。此外，TGF-β1抑制了糖酵解，这可通过减少乳酸生成并降低Glut1，Hk2，Enolase1和Hif-1α的表达来证明。用TGF-β1处理的nTregs表现出下调的mTORC1信号传导，但增强了丝氨酸-苏氨酸磷酸酶PP2A的激活。此外，用PP2A抑制剂冈田酸处理破坏了TGF-β1对Foxp3表达的维持。因此，TGF-β1可能通过PP2A激活和mTORC1调控的糖酵解的抑制来维持培养的nTregs中Foxp3的表达。