Lv Bochang, Huo Fuquan, Zhu Zhongqiao, Xu Zhiguo, Dang Xiaojie, Chen Tao, Zhang Ting, Yang Xinguang
Shaanxi Ophthalmic Medical Center, Xi'an No. 4 Hospital, Affiliated Guangren Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, People's Republic of China.
Department of Physiology and Pathophysiology, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University School of Medicine, Xi'an, 710061, People's Republic of China.
Neurochem Res. 2016 Aug;41(8):1949-57. doi: 10.1007/s11064-016-1905-1. Epub 2016 Apr 15.
Glaucoma is a group of neurodegenerative diseases characterized by the progressive loss of retinal ganglion cells (RGCs) and optic nerve fibers. Microglial activation has been shown to be deleterious to RGCs and may participate in the progression of glaucoma. Crocin, one of the major active ingredients in saffron, has been found to inhibit microglial activation. However, the mechanism remains unclear. The aim of this study was to investigate whether crocin can inhibit lipopolysaccharide (LPS)-induced microglial activation and to clarify the mechanisms involved. The influence of crocin on primary RGCs and LPS-stimulated BV2 microglial cells survival was determined by the MTT and lactate dehydrogenase assays, or by flow cytometry. BV2 cells were pretreated with various concentrations of crocin for 2 h followed by 1 μg/mL LPS stimulation. Microglial markers and pro-inflammatory mediators were assessed by real-time PCR, western blot and ELISA. Furthermore, CX3CR1 expression was detected and the underlying mechanism was examined. The concentrations of crocin ranged from 0.1 to 1 μM, and did not show any cytotoxicity in RGC and BV2 cells. After crocin pretreatment, the expression of microglial markers (CD11b and Iba-1) and pro-inflammatory mediators (iNOS, COX-2, IL-1β, and TNF-α) induced by LPS were significantly decreased in a dose-dependent manner. Additionally, CX3CR1 expression was remarkably increased by crocin via the suppression of NF-κB/Yin Yang 1 (YY1) signaling in BV2 cells. In conclusion, crocin effectively suppresses microglial activation and upregulates CX3CR1 expression by suppressing NF-κB/YY1 signaling.
青光眼是一组神经退行性疾病，其特征是视网膜神经节细胞（RGCs）和视神经纤维逐渐丧失。小胶质细胞激活已被证明对RGCs有害，并可能参与青光眼的进展。藏红花的主要活性成分之一藏红花素已被发现可抑制小胶质细胞激活。然而，其机制仍不清楚。本研究的目的是探讨藏红花素是否能抑制脂多糖（LPS）诱导的小胶质细胞激活，并阐明其中涉及的机制。通过MTT和乳酸脱氢酶测定法或流式细胞术确定藏红花素对原代RGCs和LPS刺激的BV2小胶质细胞存活的影响。BV2细胞用不同浓度的藏红花素预处理2小时，然后用1μg/mL LPS刺激。通过实时PCR、蛋白质印迹和酶联免疫吸附测定法评估小胶质细胞标志物和促炎介质。此外，检测CX3CR1表达并研究其潜在机制。藏红花素的浓度范围为0.1至1μM，在RGC和BV2细胞中未显示任何细胞毒性。藏红花素预处理后，LPS诱导的小胶质细胞标志物（CD11b和Iba-1）和促炎介质（iNOS、COX-2、IL-1β和TNF-α）的表达以剂量依赖性方式显著降低。此外，藏红花素通过抑制BV2细胞中的NF-κB/阴阳1（YY1）信号通路显著增加CX3CR1表达。总之，藏红花素通过抑制NF-κB/YY1信号通路有效抑制小胶质细胞激活并上调CX3CR1表达。
