Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, 02453, South Korea.
Department of Biomedicine & Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, 06591, South Korea.
J Neuroinflammation. 2022 Jun 11;19(1):143. doi: 10.1186/s12974-022-02512-z.
Trimethyltin (TMT) is a potent neurotoxicant that leads to hippocampal neurodegeneration. Regulatory T cells (Tregs) play an important role in maintaining the immune balance in the central nervous system (CNS), but their activities are impaired in neurodegenerative diseases. In this study, we aimed to determine whether adoptive transfer of Tregs, as a living drug, ameliorates hippocampal neurodegeneration in TMT-intoxicated mice.
CD4CD25 Tregs were expanded in vitro and adoptively transferred to TMT-treated mice. First, we explored the effects of Tregs on behavioral deficits using the Morris water maze and elevated plus maze tests. Biomarkers related to memory formation, such as cAMP response element-binding protein (CREB), protein kinase C (PKC), neuronal nuclear protein (NeuN), nerve growth factor (NGF), and ionized calcium binding adaptor molecule 1 (Iba1) in the hippocampus were examined by immunohistochemistry after killing the mouse. To investigate the neuroinflammatory responses, the polarization status of microglia was examined in vivo and in vitro using real-time reverse transcription polymerase chain reaction (rtPCR) and Enzyme-linked immunosorbent assay (ELISA). Additionally, the inhibitory effects of Tregs on TMT-induced microglial activation were examined using time-lapse live imaging in vitro with an activation-specific fluorescence probe, CDr20.
Adoptive transfer of Tregs improved spatial learning and memory functions and reduced anxiety in TMT-intoxicated mice. Additionally, adoptive transfer of Tregs reduced neuronal loss and recovered the expression of neurogenesis enhancing molecules in the hippocampi of TMT-intoxicated mice. In particular, Tregs inhibited microglial activation and pro-inflammatory cytokine release in the hippocampi of TMT-intoxicated mice. The inhibitory effects of TMT were also confirmed via in vitro live time-lapse imaging in a Treg/microglia co-culture system.
These data suggest that adoptive transfer of Tregs ameliorates disease progression in TMT-induced neurodegeneration by promoting neurogenesis and modulating microglial activation and polarization.
三甲基锡（TMT）是一种强效的神经毒素，可导致海马体神经退行性病变。调节性 T 细胞（Tregs）在维持中枢神经系统（CNS）的免疫平衡方面发挥着重要作用，但在神经退行性疾病中其活性受到损害。在这项研究中，我们旨在确定作为活药物的 Tregs 过继转移是否能改善 TMT 中毒小鼠的海马体神经退行性病变。
体外扩增 CD4CD25 Tregs 并过继转移至 TMT 处理的小鼠。首先，我们使用 Morris 水迷宫和高架十字迷宫测试来探索 Tregs 对行为缺陷的影响。在处死小鼠后，通过免疫组织化学方法检测与记忆形成相关的生物标志物，如 cAMP 反应元件结合蛋白（CREB）、蛋白激酶 C（PKC）、神经元核蛋白（NeuN）、神经生长因子（NGF）和离子钙结合接头分子 1（Iba1）在海马体中的表达。为了研究神经炎症反应，我们通过实时逆转录聚合酶链反应（rtPCR）和酶联免疫吸附测定（ELISA）在体内和体外检测小胶质细胞的极化状态。此外，我们还通过使用激活特异性荧光探针 CDr20 进行体外延时实时成像来研究 Tregs 对 TMT 诱导的小胶质细胞激活的抑制作用。
Tregs 的过继转移改善了 TMT 中毒小鼠的空间学习和记忆功能，并减轻了焦虑。此外，Tregs 的过继转移减少了神经元丢失，并恢复了 TMT 中毒小鼠海马体中神经发生增强分子的表达。特别是，Tregs 抑制了 TMT 中毒小鼠海马体中小胶质细胞的激活和促炎细胞因子的释放。这些作用也通过 Treg/小胶质细胞共培养系统中的体外延时实时成像得到了证实。
这些数据表明，通过促进神经发生和调节小胶质细胞的激活和极化，Tregs 的过继转移可改善 TMT 诱导的神经退行性病变中的疾病进展。
