CAS Key Laboratory of Receptor Research, Department of Neuropharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
School of Pharmacy, University of Chinese Academy of Sciences, Beijing, 100049, China.
Acta Pharmacol Sin. 2022 Feb;43(2):273-284. doi: 10.1038/s41401-021-00671-y. Epub 2021 May 11.
Paeoniflorin (PF), a bioactive monoterpene glucoside, has shown a variety of pharmacological effects such as anti-inflammation and autophagy modulation etc. In this study, we investigated whether and how PF exerted a protective effect against ischemic brain injury in vivo and in vitro. Primary rat cortical neurons underwent oxygen/glucose deprivation/reperfusion (OGD/R) for 90 min. We showed that after OGD/R, a short fragment of histone deacetylase 4 (HDAC4) produced by caspase3-mediated degradation was markedly accumulated in the nucleus and the activity of caspase3 was increased. Treatment with PF (100 nM, 1 μM) significantly improved the viability of cortical neurons after OGD/R. Furthermore, PF treatment could maintain HDAC4 intrinsic subcellular localization and reduce the caspase3 activity without changing the HDAC4 at the transcriptional level. PF treatment significantly reduced OGD/R-caused inhibition of transcriptional factor MEF2 expression and increased the expression of downstream proteins such as GDNF, BDNF, and Bcl-xl, thus exerting a great anti-apoptosis effect as revealed by TUNEL staining. The beneficial effects of PF were almost canceled in HDAC4 (D289E)-transfected PC12 cells after OGD/R. In addition, PF treatment reduced the caspase9 activity, rescued the release of cytochrome c from mitochondria, and maintained the integrity of mitochondria membrane. We conducted in vivo experiments in 90-min-middle cerebral artery occlusion (MCAO) rat model. The rats were administered PF (20, 40 mg/kg, ip, 3 times at the reperfusion, 24 h and 48 h after the surgery). We showed that PF administration dose-dependently reduced infarction area, improved neurological symptoms, and maintained HDAC4 localization in rats after MCAO. These results demonstrate that PF is effective in protecting against ischemic brain injury and inhibit apoptosis through inhibiting the cytochrome c/caspase3/HDAC4 pathway.
芍药苷（PF）是一种生物活性的单萜糖苷，具有多种药理作用，如抗炎和自噬调节等。在本研究中，我们研究了 PF 是否以及如何在体内和体外对缺血性脑损伤发挥保护作用。原代大鼠皮质神经元经历氧/葡萄糖剥夺/再灌注（OGD/R）90 分钟。我们发现，OGD/R 后， caspase3 介导的降解产生的组蛋白去乙酰化酶 4（HDAC4）的短片段明显积累在核内，caspase3 的活性增加。PF（100 nM，1 μM）处理可显著改善 OGD/R 后皮质神经元的活力。此外，PF 处理可维持 HDAC4 的内在亚细胞定位，并降低 caspase3 的活性，而不改变转录水平的 HDAC4。PF 处理可显著减少 OGD/R 引起的转录因子 MEF2 表达抑制，并增加下游蛋白如 GDNF、BDNF 和 Bcl-xl 的表达，从而通过 TUNEL 染色显示出强大的抗凋亡作用。在 OGD/R 后转染 HDAC4（D289E）的 PC12 细胞中，PF 的有益作用几乎被取消。此外，PF 处理可降低 caspase9 活性，从线粒体中挽救细胞色素 c 的释放，并维持线粒体膜的完整性。我们在 90 分钟大脑中动脉闭塞（MCAO）大鼠模型中进行了体内实验。大鼠给予 PF（20、40 mg/kg，ip，再灌注后 3 次，手术 24 和 48 小时）。我们表明，PF 给药剂量依赖性地减少梗死面积，改善神经症状，并维持 MCAO 后大鼠的 HDAC4 定位。这些结果表明，PF 通过抑制细胞色素 c/caspase3/HDAC4 通路有效保护缺血性脑损伤并抑制细胞凋亡。
