丙戊酸通过依赖于 HDAC3 的 STAT1 和 NF-κB 通路减轻创伤性脊髓损伤诱导的炎症。

Valproic acid attenuates traumatic spinal cord injury-induced inflammation via STAT1 and NF-κB pathway dependent of HDAC3.

机构信息

Department of Orthopaedics, The Second Affiliated Hospital, Fujian Medical Universityz, Quanzhou, 362000, Fujian Province, China.

Department of nursing faculty, Quanzhou Medical College, Quanzhou, 362000, Fujian Province, China.

出版信息

J Neuroinflammation. 2018 May 18;15(1):150. doi: 10.1186/s12974-018-1193-6.

DOI:10.1186/s12974-018-1193-6

PMID:29776446

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5960086/

Abstract

BACKGROUND

Microglial polarization with M1/M2 phenotype shifts and the subsequent neuroinflammatory responses are vital contributing factors for spinal cord injury (SCI)-induced secondary injury. Nuclear factor-κB (NF-κB) is considered the central transcription factor of inflammatory mediators, which plays a crucial role in microglial activation. Lysine acetylation of STAT1 seems necessary for NF-kB pathway activity, as it is regulated by histone deacetylases (HDACs). There have been no studies that have explained if HDAC inhibition by valproic acid (VPA) affects the NF-κB pathway via acetylation of STAT1 dependent of HDAC activity in the microglia-mediated central inflammation following SCI. We investigated the potential molecular mechanisms that focus on the phenotypic transition of microglia and the STAT1-mediated NF-κB acetylation after a VPA treatment.

METHODS

The Basso-Beattie-Bresnahan locomotion scale, the inclined plane test, the blood-spinal cord barrier, and Nissl staining were employed to determine the neuroprotective effects of VPA treatment after SCI. Assessment of microglia polarization and pro-inflammatory markers, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and interferon (INF)-γ was used to evaluate the neuroinflammatory responses and the anti-inflammatory effects of VPA treatment. Immunofluorescent staining and Western blot analysis were used to detect HDAC3 nuclear translocation, activity, and NF-κB signaling pathway activation to evaluate the effects of VPA treatment. The impact of STAT1 acetylation on NF-kB pathway and the interaction between STAT1 and NF-kB were assessed to evaluate anti-inflammation effects of VPA treatment and also whether these effects were dependent on a STAT1/NF-κB pathway to gain further insight into the mechanisms underlying the development of the neuroinflammatory response after SCI.

RESULTS

The results showed that the VPA treatment promoted the phenotypic shift of microglia from M1 to M2 phenotype and inhibited microglial activation, thus reducing the SCI-induced inflammatory factors. The VPA treatment upregulation of the acetylation of STAT1/NF-κB pathway was likely caused by the HDAC3 translocation to the nucleus and activity. These results indicated that the treatment with the VPA suppressed the expression and the activity of HDAC3 and enhanced STAT1, as well as NF-κB p65 acetylation following a SCI. The acetylation status of NF-kB p65 and the complex with NF-κB p65 and STAT1 inhibited the NF-kB p65 transcriptional activity and attenuated the microglia-mediated central inflammatory response following SCI.

CONCLUSIONS

These results suggested that the VPA treatment attenuated the inflammatory response by modulating microglia polarization through STAT1-mediated acetylation of the NF-κB pathway, dependent of HDAC3 activity. These effects led to neuroprotective effects following SCI.

摘要

背景

小胶质细胞极化表现为 M1/M2 表型转变，随后的神经炎症反应是脊髓损伤（SCI）引起继发性损伤的重要因素。核因子-κB（NF-κB）被认为是炎症介质的核心转录因子，在小胶质细胞激活中起着至关重要的作用。STAT1 的赖氨酸乙酰化似乎是 NF-kB 途径活性所必需的，因为它受组蛋白去乙酰化酶（HDACs）的调节。目前还没有研究表明丙戊酸（VPA）通过抑制 HDAC 活性来抑制 HDAC，是否会影响 STAT1 依赖性 NF-κB 乙酰化，从而影响 SCI 后小胶质细胞介导的中枢炎症中的 NF-κB 途径。我们研究了潜在的分子机制，重点是小胶质细胞表型转变和 STAT1 介导的 NF-κB 乙酰化，以及 VPA 治疗后的变化。

方法

巴索-比蒂-布雷森汉姆运动量表、斜面试验、血脊髓屏障和尼氏染色用于确定 SCI 后 VPA 治疗的神经保护作用。评估小胶质细胞极化和促炎标志物，如肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β、IL-6 和干扰素（INF）-γ，以评估 VPA 治疗的神经炎症反应和抗炎作用。免疫荧光染色和 Western blot 分析用于检测 HDAC3 核易位、活性和 NF-κB 信号通路激活，以评估 VPA 治疗的作用。评估 STAT1 乙酰化对 NF-kB 途径的影响以及 STAT1 和 NF-kB 之间的相互作用，以评估 VPA 治疗的抗炎作用，以及这些作用是否依赖于 STAT1/NF-κB 途径，以深入了解 SCI 后神经炎症反应的发展机制。

结果

结果表明，VPA 治疗促进了小胶质细胞从 M1 向 M2 表型的表型转变，并抑制了小胶质细胞的激活，从而减少了 SCI 引起的炎症因子。VPA 治疗上调 STAT1/NF-κB 途径的乙酰化可能是由于 HDAC3 向核内易位和活性所致。这些结果表明，VPA 治疗抑制了 SCI 后 HDAC3 的表达和活性，并增强了 STAT1 和 NF-κB p65 的乙酰化。NF-kB p65 的乙酰化状态以及与 NF-kB p65 和 STAT1 的复合物抑制了 NF-kB p65 的转录活性，并减弱了 SCI 后小胶质细胞介导的中枢炎症反应。