Department of Neurosurgery, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, 400038, China.
Department of Neurosurgery, the 904th Hospital of PLA, School of Medicine of Anhui Medical University, Wuxi, Jiangsu Province, 214044, China.
CNS Neurosci Ther. 2023 Aug;29(8):2327-2338. doi: 10.1111/cns.14184. Epub 2023 Mar 25.
Functional recovery is associated with the preservation of dendritic spines in the penumbra area after stroke. Previous studies found that polymerized microtubules (MTs) serve a crucial role in regulating dendritic spine formation and plasticity. However, the mechanisms that are involved are poorly understood. This study is designed to understand whether the upregulation of acetylated α-tubulin (α-Ac-Tub, a marker for stable, and polymerized MTs) could alleviate injury to the dendritic spines in the penumbra area and motor dysfunction after ischemic stroke.
Ischemic stroke was mimicked both in an in vivo and in vitro setup using middle cerebral artery occlusion and oxygen-glucose deprivation models. Thy1-YFP mice were utilized to observe the morphology of the dendritic spines in the penumbra area. MEC17 is the specific acetyltransferase of α-tubulin. Thy1 Cre and MEC17 mice were mated to produce mice with decreased expression of α-Ac-Tub in dendritic spines of pyramidal neurons in the cerebral cortex. Moreover, AAV-PHP.B-DIO-MEC17 virus and tubastatin A (TBA) were injected into Thy1 Cre and Thy1-YFP mice to increase α-Ac-Tub expression. Single-pellet retrieval, irregular ladder walking, rotarod, and cylinder tests were performed to test the motor function after the ischemic stroke.
α-Ac-Tub was colocalized with postsynaptic density 95. Although knockout of MEC17 in the pyramidal neurons did not affect the density of the dendritic spines, it significantly aggravated the injury to them in the penumbra area and motor dysfunction after stroke. However, MEC17 upregulation in the pyramidal neurons and TBA treatment could maintain mature dendritic spine density and alleviate motor dysfunction after stroke.
Our study demonstrated that α-Ac-Tub plays a crucial role in the maintenance of the structure and functions of mature dendritic spines. Moreover, α-Ac-Tub protected the dendritic spines in the penumbra area and alleviated motor dysfunction after stroke.
功能恢复与卒中后半影区树突棘的保留有关。先前的研究发现，聚合微管（MTs）在调节树突棘形成和可塑性方面起着至关重要的作用。然而，其相关机制尚不清楚。本研究旨在了解乙酰化微管相关蛋白α-Tubulin（α-Ac-Tub，稳定聚合 MTs 的标志物）的上调是否能减轻缺血性卒中后半影区树突棘损伤和运动功能障碍。
在体内和体外使用大脑中动脉闭塞和氧葡萄糖剥夺模型模拟缺血性卒中。利用 Thy1-YFP 小鼠观察半影区树突棘的形态。MEC17 是 α-微管蛋白的特异性乙酰转移酶。Thy1 Cre 和 MEC17 小鼠交配，产生大脑皮质锥体神经元树突棘中 α-Ac-Tub 表达减少的小鼠。此外，将 AAV-PHP.B-DIO-MEC17 病毒和 tubastatin A（TBA）注射到 Thy1 Cre 和 Thy1-YFP 小鼠中，以增加 α-Ac-Tub 的表达。进行单次颗粒回收、不规则梯级行走、转棒和圆筒试验，以测试缺血性卒中后的运动功能。
α-Ac-Tub 与突触后密度蛋白 95 共定位。虽然 MEC17 在锥体神经元中的敲除不影响树突棘的密度，但它显著加重了缺血性卒中后半影区的损伤和运动功能障碍。然而，MEC17 在锥体神经元中的上调和 TBA 处理可以维持成熟树突棘的密度并减轻卒中后的运动功能障碍。
本研究表明，α-Ac-Tub 在维持成熟树突棘的结构和功能中起着关键作用。此外，α-Ac-Tub 保护半影区的树突棘并减轻卒中后的运动功能障碍。
