Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany.
FibroGen, Inc., San Francisco, California, United States of America.
PLoS One. 2014 Jan 7;9(1):e84767. doi: 10.1371/journal.pone.0084767. eCollection 2014.
Ischemic stroke results in disruption of the blood-brain barrier (BBB), edema formation and neuronal cell loss. Some neuroprotective factors such as vascular endothelial growth factor (VEGF) favor edema formation, while others such as erythropoietin (Epo) can mitigate it. Both factors are controlled by hypoxia inducible transcription factors (HIF) and the activity of prolyl hydroxylase domain proteins (PHD). We hypothesize that activation of the adaptive hypoxic response by inhibition of PHD results in neuroprotection and prevention of vascular leakage. Mice, subjected to cerebral ischemia, were pre- or post-treated with the novel PHD inhibitor FG-4497. Inhibition of PHD activity resulted in HIF-1α stabilization, increased expression of VEGF and Epo, improved outcome from ischemic stroke and reduced edema formation by maintaining BBB integrity. Additional in vitro studies using brain endothelial cells and primary astrocytes confirmed that FG-4497 induces the HIF signaling pathway, leading to increased VEGF and Epo expression. In an in vitro ischemia model, using combined oxygen and glucose deprivation, FG-4497 promoted the survival of neurons. Furthermore, FG-4497 prevented the ischemia-induced rearrangement and gap formation of the tight junction proteins zonula occludens 1 and occludin, both in cultured endothelial cells and in infarcted brain tissue in vivo. These results indicate that FG-4497 has the potential to prevent cerebral ischemic damage by neuroprotection and prevention of vascular leakage.
缺血性脑卒中导致血脑屏障(BBB)破坏、水肿形成和神经元细胞死亡。一些神经保护因子,如血管内皮生长因子(VEGF),有利于水肿形成,而另一些因子,如促红细胞生成素(Epo),则可以减轻水肿。这两种因子都受缺氧诱导转录因子(HIF)和脯氨酰羟化酶结构域蛋白(PHD)的活性调控。我们假设通过抑制 PHD 来激活适应性缺氧反应会导致神经保护和防止血管渗漏。将小鼠置于脑缺血模型中,用新型 PHD 抑制剂 FG-4497 进行预处理或后处理。抑制 PHD 活性导致 HIF-1α稳定,增加 VEGF 和 Epo 的表达,改善缺血性脑卒中的预后,并通过维持 BBB 完整性减少水肿形成。使用脑内皮细胞和原代星形胶质细胞进行的额外体外研究证实,FG-4497 诱导 HIF 信号通路,导致 VEGF 和 Epo 表达增加。在体外缺血模型中,使用联合氧和葡萄糖剥夺,FG-4497 促进神经元的存活。此外,FG-4497 可防止缺血诱导的紧密连接蛋白 zonula occludens 1 和 occludin 的重排和间隙形成,这在体外培养的内皮细胞和体内梗死脑组织中均有体现。这些结果表明,FG-4497 通过神经保护和防止血管渗漏,具有预防脑缺血损伤的潜力。