State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Beijing Key Laboratory of Drug Target Identification and Drug Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
Oxid Med Cell Longev. 2021 Oct 4;2021:6521146. doi: 10.1155/2021/6521146. eCollection 2021.
Oxidative stress and neuroinflammation have been demonstrated to be linked with Alzheimer's disease (AD). In this study, we examined the protective effects of DL0410 in aging rats and explored the underlying mechanism against oxidative damage and neuroinflammation, which was then validated in LPS-stimulated BV2 microglia. We firstly investigated the improvement effects of DL0410 on learning and memory abilities and explored the potential mechanisms in D-gal-induced aging rats. An 8-week treatment with DL0410 significantly improved the learning and cognitive function of D-gal-stimulated Alzheimer's-like rats in the Morris water maze test, step-down test, and novel object recognition test, and the therapeutic effect of DL0410 at 10 mg/kg was even better than that of donepezil. What is more, the results showed that DL0410 alleviated neuron injury, increased the number of synapses, and improved the level of postsynaptic density protein 95 (PSD95) in the hippocampus and cortex. Next, we examined the protective effects of DL0410 against oxidative damage and neuroinflammation. Our observations indicated that DL0410 reduced the production of harmful oxidation products and promoted the antioxidative system, decreased the levels of proinflammatory cytokines, including tumor necrosis factor (TNF-), interleukin 1 (IL-1), and interleukin 6 (IL-6), and increased anti-inflammatory cytokines IL-10. Moreover, DL0410 inhibited the activation of astrocytes and microglia and suppressed the activation of the TLR4/MyD88/NF-B signaling pathway. The anti-inflammation effect of DL0410 was further confirmed in LPS-stimulated BV2 cells, and the results showed that DL0410 reduced the level of inflammatory factors and inhibited the activation of the TLR4/MyD88/TRAF6/NF-B signaling pathway in BV2 microglia. Molecular docking results indicated that DL0410 occupied the LPS recognition site in the TLR4/MD2 complex. Furthermore, the enhanced expression of claudin-1, claudin-5, occludin, CX43, and ZO-1 indicated that DL0410 protected the blood-brain barrier (BBB) integrity. Together, these results suggest that DL0410 exerts neuroprotective effects against hippocampus and cortex injury induced by D-galactose, and the possible mechanisms include antioxidative stress, antineuroinflammation, improving synaptic plasticity, and maintaining BBB integrity, which is mediated by the TLR4/MyD88/NF-B signaling pathway inhibition. We suggest that DL0410 is a promising candidate for AD treatment.
氧化应激和神经炎症已被证明与阿尔茨海默病（AD）有关。在这项研究中，我们研究了 DL0410 在衰老大鼠中的保护作用，并探讨了其针对氧化损伤和神经炎症的潜在机制，然后在 LPS 刺激的 BV2 小胶质细胞中进行了验证。我们首先研究了 DL0410 改善 D-半乳糖诱导衰老大鼠学习和记忆能力的作用，并探讨了其潜在机制。8 周的 DL0410 治疗可显著改善 D-半乳糖诱导的阿尔茨海默病样大鼠在 Morris 水迷宫测试、跳下测试和新物体识别测试中的学习和认知功能，且 DL0410 的 10mg/kg 治疗效果甚至优于多奈哌齐。更重要的是，结果表明，DL0410 减轻了神经元损伤，增加了突触数量，并改善了海马体和皮质中突触后密度蛋白 95（PSD95）的水平。接下来，我们研究了 DL0410 对氧化损伤和神经炎症的保护作用。我们的观察表明，DL0410 减少了有害氧化产物的产生并促进了抗氧化系统，降低了促炎细胞因子（包括肿瘤坏死因子（TNF-）、白细胞介素 1（IL-1）和白细胞介素 6（IL-6））的水平，并增加了抗炎细胞因子 IL-10。此外，DL0410 抑制了星形胶质细胞和小胶质细胞的激活，并抑制了 TLR4/MyD88/NF-B 信号通路的激活。DL0410 在 LPS 刺激的 BV2 细胞中的抗炎作用也得到了进一步证实，结果表明，DL0410 降低了炎症因子的水平，并抑制了 TLR4/MyD88/TRAF6/NF-B 信号通路在 BV2 小胶质细胞中的激活。分子对接结果表明，DL0410 占据了 TLR4/MD2 复合物中的 LPS 识别位点。此外，Claudin-1、Claudin-5、Occludin、CX43 和 ZO-1 的增强表达表明，DL0410 保护了血脑屏障（BBB）的完整性。综上所述，这些结果表明，DL0410 对 D-半乳糖诱导的海马体和皮质损伤具有神经保护作用，其可能的机制包括抗氧化应激、抗神经炎症、改善突触可塑性和维持 BBB 完整性，这是通过 TLR4/MyD88/NF-B 信号通路抑制介导的。我们建议 DL0410 是治疗 AD 的一种有前途的候选药物。
