Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China.
Department of Ophthalmology, Forth People's Hospital, Shenyang, China.
Brain Res Bull. 2019 Aug;150:42-49. doi: 10.1016/j.brainresbull.2019.05.005. Epub 2019 May 16.
Traumatic brain injury (TBI) triggers neuronal death mechanisms that significantly induce neuronal loss and neurological dysfunction. Our previous study revealed that Sirt1 could improve the neuroprotective effect by reducing the astrocyte activation after TBI. Nevertheless, the underlying mechanisms of Sirt1 attenuating astrocyte activation still remain unclear. The following study examined whether the protection of Sirt1 in nigrostriatal pathway injury is associated with autophagy regulation. We established a nigrostriatal pathway injury in the mouse brain in order to mimic the traumatic brain injury and up-regulated Sirt1 expression by resveratrol. Consequently, we analyzed the effect of Sirt1 up-regulation on LC3 and monitored the LC3 localization in the astrocytes, microglial cells and neurons. We found that the Sirt1 up-regulation by resveratrol increased the expression of LC3 around the lesion site after injury. Confocal results showed that Sirt1 up-regulation increased the expression of LC3 in astrocytes and decreased the expression in the neurons, while low effect was found on the microglial cells. Moreover, compared the resveratrol treatment groups, a typical nucleocytoplasmic localization with strong distribution in the nucleus (in astrocyte and neurons) was observed in the control group (treated with DMSO). To sum up, our data suggested that regulation of Sirt1 expression could enhance autophagy in the astrocytes and decrease the expression in the neurons. This mechanism, which may probably relate to the distribution of LC3 in cytoplasm and nucleus, provides a new theoretical basis for exploring the neuroprotective mechanism of Sirt1 after brain injury.
创伤性脑损伤 (TBI) 触发神经元死亡机制,导致神经元大量丢失和神经功能障碍。我们之前的研究表明,Sirt1 可以通过减少 TBI 后星形胶质细胞的激活来提高神经保护作用。然而,Sirt1 减轻星形胶质细胞激活的潜在机制仍不清楚。本研究旨在探讨 Sirt1 是否通过调节自噬来保护黑质纹状体通路损伤。我们在小鼠大脑中建立了黑质纹状体通路损伤模型,并用白藜芦醇上调 Sirt1 表达。因此,我们分析了 Sirt1 上调对 LC3 的影响,并监测了 LC3 在星形胶质细胞、小胶质细胞和神经元中的定位。结果发现,白藜芦醇上调 Sirt1 表达可增加损伤后病变部位周围 LC3 的表达。共聚焦结果表明,Sirt1 上调增加了星形胶质细胞中 LC3 的表达,减少了神经元中的表达,而对小胶质细胞的影响较小。此外,与白藜芦醇处理组相比,对照组(用 DMSO 处理)观察到 LC3 具有典型的核质定位,在星形胶质细胞和神经元中有较强的核内分布。总之,我们的数据表明,Sirt1 表达的调节可以增强星形胶质细胞中的自噬,并减少神经元中的表达。这种机制可能与 LC3 在细胞质和细胞核中的分布有关,为探索脑损伤后 Sirt1 的神经保护机制提供了新的理论依据。