Jingxuan Lian, Litian Ma, Yanyang Tu, Jianfang Fu
Department of Endocrinology, Xijing Hospital, The Air Force Medical University, Xi'an 710032, China.
Department of Gastroenterology, Tangdu Hospital, The Air Force Medical University, Xi'an 710038, China.
Diabetes Res Clin Pract. 2022 Aug;190:109970. doi: 10.1016/j.diabres.2022.109970. Epub 2022 Jul 2.
Diabetic encephalopathy(DE) is a neurological complication of diabetes, and its pathogenesis is unclear. Current studies indicate that insulin receptors and downstream signaling pathways play a key role in the occurrence and development of DE. Additionally, CLC-3, a member of the CLC family of anion channels and transporters, is closely related to the secretion and processing of insulin. Here, we investigated the changes and putative roles of CLC-3 in diabetic encephalopathy.
To this aim, we combined lentivirus and adeno-associated virus gene transfer to change the expression level of CLC-3 in the HT-22 hippocampal cell line and hippocampal CA1. We studied the role of CLC-3 in DE through the Morris water maze test.CLC-3 expression increased significantly in HT-22 cells cultured with high glucose and STZ-induced DE model hippocampus. Moreover, Insulin receptor(IR) and downstream PI3K/AKT/GSK3β signaling pathways were also dysfunctional. After knocking down CLC-3, impaired cell proliferation, apoptosis, IR and the downstream PI3K/AKT/GSK3β signaling pathways were significantly improved. However, when CLC-3 was overexpressed, the neurotoxicity induced by high glucose was further aggravated. Rescue experiments found that through the use of inhibitors such as GSK3β, the PI3K/AKT/GSK3β signaling pathways pathway changes with the use of inhibition, and the expression of related downstream signaling molecules such as Tau and p-Tau also changes accordingly. Using adeno-associated virus gene transfer to knock down CLC-3 in the hippocampal CA1 of the DE model, the IR caused by DE and the dysfunction of the downstream PI3K/AKT/GSK3β signaling pathway were significantly improved. In addition, the impaired spatial recognition of DE was partially restored.
Our study proposes that CLC-3, as a key molecule, may regulate insulin receptor signaling and downstream PI3K/AKT/GSK3β signaling pathways and affect the pathogenesis of diabetic encephalopathy.
糖尿病性脑病（DE）是糖尿病的一种神经并发症，其发病机制尚不清楚。目前的研究表明，胰岛素受体和下游信号通路在DE的发生发展中起关键作用。此外，CLC-3是阴离子通道和转运体CLC家族的成员之一，与胰岛素的分泌和加工密切相关。在此，我们研究了CLC-3在糖尿病性脑病中的变化及潜在作用。
为此，我们结合慢病毒和腺相关病毒基因转移来改变HT-22海马细胞系和海马CA1区中CLC-3的表达水平。我们通过莫里斯水迷宫试验研究了CLC-3在DE中的作用。在高糖培养的HT-22细胞和链脲佐菌素诱导的DE模型海马中，CLC-3表达显著增加。此外，胰岛素受体（IR）和下游PI3K/AKT/GSK3β信号通路也功能失调。敲低CLC-3后，受损的细胞增殖、凋亡、IR及下游PI3K/AKT/GSK3β信号通路得到显著改善。然而，当CLC-3过表达时，高糖诱导的神经毒性进一步加重。拯救实验发现，通过使用GSK3β等抑制剂，PI3K/AKT/GSK3β信号通路随抑制作用而改变，Tau和p-Tau等相关下游信号分子的表达也相应改变。利用腺相关病毒基因转移在DE模型的海马CA1区敲低CLC-3，DE所致的IR及下游PI3K/AKT/GSK3β信号通路功能障碍得到显著改善。此外，DE受损的空间识别能力部分得到恢复。
我们的研究提出，CLC-3作为关键分子，可能调节胰岛素受体信号及下游PI3K/AKT/GSK3β信号通路，并影响糖尿病性脑病的发病机制。
