Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, No.134 Dong Street, Fuzhou, 350001, Fujian, People's Republic of China.
Center for Experimental Research in Clinical Medicine, Fujian Provincial Hospital, No.134 Dong Street, Fuzhou, 350001, Fujian, People's Republic of China.
Neuromolecular Med. 2023 Sep;25(3):415-425. doi: 10.1007/s12017-023-08745-2. Epub 2023 Apr 5.
Neurodegenerative diseases and postoperative cognitive dysfunction involve the accumulation of β-amyloid peptide (Aβ). High glucose can inhibit autophagy, which facilitates intracellular Aβ clearance. The α2-adrenoreceptor agonist dexmedetomidine (DEX) can provide neuroprotection against several neurological diseases; however, the mechanism remains unclear. This study investigated whether DEX regulated autophagy via the AMPK/mTOR pathway to improve high glucose-induced neurotoxicity in SH-SY5Y/APP695 cells. SH-SY5Y/APP695 cells were cultured with high glucose with/without DEX. To examine the role of autophagy, the autophagy activator rapamycin (RAPA) and autophagy inhibitor 3-methyladenine (3-MA) were used. The selective AMPK inhibitor compound C was used to investigate the involvement of the AMPK pathway. Cell viability and apoptosis were examined by CCK-8 and annexin V-FITC/PI flow cytometric assays, respectively. Autophagy was analyzed by monodansylcadaverine staining of autophagic vacuoles. Autophagy- and apoptosis-related protein expression and the phosphorylation levels of AMPK/mTOR pathway molecules were quantified by western blotting. DEX pretreatment significantly suppressed high glucose-induced neurotoxicity in SH-SY5Y/APP695 cells, as evidenced by the enhanced viability, restoration of cellular morphology, and reduction in apoptotic cells. Furthermore, RAPA had a protective effect similar to that of DEX, but 3-MA eliminated the protective effect of DEX by promoting mTOR activation. Moreover, the AMPK/mTOR pathway was involved in DEX-mediated autophagy. Compound C significantly suppressed autophagy and reversed the protective effect of DEX against high glucose in SH-SY5Y/APP695 cells. Our findings demonstrated that DEX protected SH-SY5Y/APP695 cells against high glucose-induced neurotoxicity by upregulating autophagy through the AMPK/mTOR pathway, suggesting a role of DEX in treating POCD in diabetic patients.
神经退行性疾病和术后认知功能障碍涉及β-淀粉样肽（Aβ）的积累。高葡萄糖可以抑制自噬，从而促进细胞内 Aβ的清除。α2-肾上腺素受体激动剂右美托咪定（DEX）可提供对几种神经退行性疾病的神经保护；然而，其机制尚不清楚。本研究探讨了 DEX 是否通过 AMPK/mTOR 通路调节自噬来改善高葡萄糖诱导的 SH-SY5Y/APP695 细胞神经毒性。将 SH-SY5Y/APP695 细胞在高葡萄糖中培养，有/无 DEX。为了研究自噬的作用，使用了自噬激活剂雷帕霉素（RAPA）和自噬抑制剂 3-甲基腺嘌呤（3-MA）。使用选择性 AMPK 抑制剂化合物 C 来研究 AMPK 通路的参与。通过 CCK-8 和 annexin V-FITC/PI 流式细胞术分别检测细胞活力和细胞凋亡。通过单丹磺酰尸胺染色自噬空泡分析自噬。通过 Western blot 定量分析自噬和凋亡相关蛋白表达以及 AMPK/mTOR 通路分子的磷酸化水平。DEX 预处理可显著抑制 SH-SY5Y/APP695 细胞的高葡萄糖诱导的神经毒性，表现为活力增强、细胞形态恢复和凋亡细胞减少。此外，RAPA 具有与 DEX 相似的保护作用，但 3-MA 通过促进 mTOR 激活消除了 DEX 的保护作用。此外，AMPK/mTOR 通路参与了 DEX 介导的自噬。化合物 C 可显著抑制自噬，并逆转 DEX 对 SH-SY5Y/APP695 细胞高葡萄糖的保护作用。我们的研究结果表明，DEX 通过 AMPK/mTOR 通路上调自噬来保护 SH-SY5Y/APP695 细胞免受高葡萄糖诱导的神经毒性，提示 DEX 在治疗糖尿病患者 POCD 中的作用。
