Department of Orthopaedics, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, PR China.
Department of Radiology, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, PR China.
Life Sci. 2020 Nov 1;260:118098. doi: 10.1016/j.lfs.2020.118098. Epub 2020 Jul 14.
Spinal cord injury (SCI) is one of the most devastating diseases that challenges neurology and medicine, leading to paraplegia or quadriplegia worldwide. Neuroprotection conferred by histone deacetylase (HDAC) inhibitors against various insults and deficits in the central nervous system has been reported previously. Herein, we set out to ascertain whether HDAC3 inhibition exerts neuroprotective effects against SCI.
A modified Allen's weight-drop method was performed to induce experimental SCI in rats. Basso-Beattie-Bresnahan (BBB) scores were used to assess locomotor function. Flow cytometric analysis of AnnexinV-FITC/PI double staining, TUNEL staining, and immunoblotting analysis of apoptosis-related proteins were performed to determine apoptosis in HO-induced cell injury of primary rat neurons.
Upregulated HDAC3 and downregulated miR-27a were observed in spinal cord tissues of SCI rats and HO-injured neurons. HDAC3 knockdown by its specific shRNA restored the locomotor function of SCI rats and prevented rat neurons from HO-induced apoptosis through promotion of miR-27a. miR-27a targeted PAK6 (encoding P21-activated kinase 6) and inhibited its expression. The effects of HDAC3 knockdown on the locomotor function of SCI rats and HO-induced apoptosis of rat neurons were lost upon further PAK6 overexpression.
The present study uncovers that silencing HDAC3 inhibited PAK6 expression by upregulating miR-27a, eventually inhibiting neuron apoptosis and promoting the recovery of SCI, which might provide a novel therapeutic target for SCI.
脊髓损伤（SCI）是神经学和医学面临的最具破坏性的疾病之一，导致全球范围内出现截瘫或四肢瘫痪。先前已有报道称，组蛋白去乙酰化酶（HDAC）抑制剂对中枢神经系统的各种损伤和缺陷具有神经保护作用。在此，我们旨在确定 HDAC3 抑制是否对 SCI 具有神经保护作用。
采用改良的 Allen 重物坠落法诱导大鼠实验性 SCI。Basso-Beattie-Bresnahan（BBB）评分用于评估运动功能。通过流式细胞术分析 AnnexinV-FITC/PI 双重染色、TUNEL 染色和凋亡相关蛋白的免疫印迹分析，确定原代大鼠神经元中 HO 诱导的细胞损伤中的细胞凋亡。
SCI 大鼠脊髓组织和 HO 损伤神经元中观察到 HDAC3 上调和 miR-27a 下调。其特异性 shRNA 敲低 HDAC3 通过促进 miR-27a 恢复 SCI 大鼠的运动功能，并防止大鼠神经元发生 HO 诱导的凋亡。miR-27a 靶向 PAK6（编码 P21 激活激酶 6）并抑制其表达。进一步过表达 PAK6 后，HDAC3 敲低对 SCI 大鼠运动功能和 HO 诱导的大鼠神经元凋亡的影响消失。
本研究揭示了沉默 HDAC3 通过上调 miR-27a 抑制 PAK6 表达，最终抑制神经元凋亡并促进 SCI 恢复，这可能为 SCI 提供新的治疗靶点。
