Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, China.
Biosci Rep. 2022 Apr 29;42(4). doi: 10.1042/BSR20212584.
The potential health hazards of microwaves have attracted much more attention. Our previous study found that 2856 MHz microwave radiation damaged synaptic plasticity and activated autophagy in neurons. However, the mechanisms underlying microwave-induced autophagy were still unclear. In the present study, we established neuronal damage models by exposing rat hippocampal neurons and rat adrenal pheochromocytoma (PC12) cell-derived neuron-like cells to 30 mW/cm2 microwaves, which resulted in miR-30a-5p ('miR-30a' for short) down-regulation and autophagy activation in vivo and in vitro. Bioinformatics analysis was conducted, and Beclin1, Prkaa2, Irs1, Pik3r2, Rras2, Ddit4, Gabarapl2 and autophagy-related gene 12 (Atg12) were identified as potential downstream genes of miR-30a involved in regulating autophagy. Based on our previous findings that microwave radiation could lead to abnormal energy metabolism in neurons, Prkaa2, encoding adenosine 5'-monophosphate-activated protein kinase (AMPK) α2 (AMPKα2, an important catalytic subunit of energy sensor AMPK), was selected for further analysis. Dual-luciferase reporter assay results showed that Prkaa2 was a downstream gene of miR-30a. Moreover, microwave radiation increased the expression of AMPKα2 and the phosphorylation of AMPKα (Thr172) both in vivo and in vitro. The transfection of PC12 cells with miR-30a mimics increased miR-30a levels, reduced AMPKα2 expression, suppressed AMPKα (Thr172) phosphorylation, and inhibited autophagy occurrence in neuron-like cells. Importantly, miR-30a overexpression abolished microwave-activated autophagy and inhibited microwave-induced AMPKα2 up-regulation and AMPKα (Thr172) phosphorylation. In conclusion, microwave radiation promoted the occurrence of autophagy in neurons through the miR-30a/AMPKα2 signal pathway.
微波的潜在健康危害引起了更多关注。我们之前的研究发现，2856MHz 微波辐射损伤了神经元的突触可塑性并激活了自噬。然而，微波诱导自噬的机制尚不清楚。在本研究中，我们通过暴露大鼠海马神经元和大鼠肾上腺嗜铬细胞瘤（PC12）细胞衍生的神经元样细胞于 30mW/cm2 的微波下，建立了神经元损伤模型，导致体内和体外 miR-30a-5p（简称 miR-30a）下调和自噬激活。进行了生物信息学分析，鉴定出 Beclin1、Prkaa2、Irs1、Pik3r2、Rras2、Ddit4、Gabarapl2 和自噬相关基因 12（Atg12）是 miR-30a 调节自噬的潜在下游基因。基于我们之前的发现，即微波辐射可导致神经元异常能量代谢，选择编码腺苷 5'-单磷酸激活蛋白激酶（AMPK）α2（AMPKα2，能量传感器 AMPK 的重要催化亚基）的 Prkaa2 进行进一步分析。双荧光素酶报告基因实验结果表明 Prkaa2 是 miR-30a 的下游基因。此外，微波辐射在体内和体外均增加了 AMPKα2 的表达和 AMPKα（Thr172）的磷酸化。在 PC12 细胞中转染 miR-30a 模拟物增加了 miR-30a 水平，降低了 AMPKα2 的表达，抑制了 AMPKα（Thr172）的磷酸化，并抑制了神经元样细胞中的自噬发生。重要的是，miR-30a 过表达消除了微波激活的自噬，并抑制了微波诱导的 AMPKα2 上调和 AMPKα（Thr172）磷酸化。总之，微波辐射通过 miR-30a/AMPKα2 信号通路促进神经元自噬的发生。
