Indirubin and its derivatives have been reported to exhibit anti-cancer and anti-inflammatory activities. Recently, some of its derived analogs have been shown to have neuroprotective potential. Endoplasmic reticulum (ER) stress has been demonstrated to contribute to the pathogenesis of various neurodegenerative diseases, whereas the effects of indirubin derivatives on ER stress-induced cell death have not been addressed. In the present study, a series of 44 derivatives of indirubin was prepared to search for a novel class of neuroprotective agents against ER stress-induced neuronal death. The MTT reduction assay indicated that tunicamycin (TM), an inducer of ER stress, significantly decreased the viability of hippocampal neuronal HT22 cells. Among the compounds tested, eight showed significant inhibitory activity against TM-induced cell death. Western blot analysis showed that application of these analogs to the cells simultaneously with TM reduced the TM-induced expression of CHOP, an established mediator of ER stress. Our results suggest that the preventive effect of these indirubin derivatives against ER stress-induced neuronal death may be due, at least in part, to attenuation of the CHOP-dependent signaling system.

据报道，靛玉红及其衍生物表现出抗癌和抗炎活性。最近，一些衍生的类似物已显示具有神经保护潜力。内质网（ER）应激已被证明有助于各种神经退行性疾病的发病机理，而靛玉红衍生物对ER应激诱导的细胞死亡的影响尚未得到解决。在本研究中，准备了一系列靛玉红的44种衍生物，以寻找针对ER应激引起的神经元死亡的新型神经保护剂。MTT降低试验表明，内质网应激的诱导剂衣霉素（TM）显着降低了海马神经元HT22细胞的活力。在测试的化合物中，有八种显示出对TM诱导的细胞死亡的显着抑制活性。蛋白质印迹分析表明，将这些类似物与TM同时应用于细胞会降低TM诱导的CHOP的表达，而CHOP是ER应激的既定介质。我们的结果表明，这些靛玉红衍生物对内质网应激诱导的神经元死亡的预防作用可能至少部分是由于CHOP依赖性信号传导系统的减弱。