Lei Xiaofeng, Lei Lijian, Zhang Zhelin, Zhang Zhiqing, Cheng Yan
Department of Neurology Medicine, Tianjin Medical University General Hospital Tanjin 300052, China ; Department of Neurology Medicine, Tianjin 4th Center Hospital Tianjin 300140, China.
School of Public Health, Shanxi Medical University Taiyuan, Shanxi 030001, China.
Int J Clin Exp Pathol. 2015 Feb 1;8(2):1565-74. eCollection 2015.
Beta-site Amyloid precursor protein Cleaving Enzyme 1 (BACE1) is conceived as a potential target for therapies against Alzheimer disease (AD) which is characterized by the accumulation of plaques formed of short β-amyloid (APPβ) peptides. Recently, such microRNAs, as miR-29a, miR-29b-1 have been shown to correlate with abnormally high levels of BACE1 and APPβ in sporadic AD.
In order to confirm whether miR-29c correlates with the BACE1 upregulation in sporadic AD, we firstly evaluated the expression of miR-29c and BACE1, the APPβ accumulation in sporadic AD brain tissues and analyzed the correlation of miR-29c with BACE1. Then we determined the regulation of miR-29c in human heuroblastoma SH-SY5Y cells on the BACE1 expression and APPβ accumulation. And finally we determined the targeting to 3' UTR of BACE1 by miR-29c by a luciferase reporter.
It was demonstrated that miR-29c was downregulated in sporadic AD brains, in an association with an upregulation of BACE1 in both mRNA and protein level of BACE1, and also an elevated APPβ accumulation. And the manipulated high level of miR-29c with miR-29c mimics transfection significantly reduced the protein level of BACE1 and APPβ accumulation in human neuroblastoma SH-SY5Y cells. Further luciferase reporter assay demonstrated that miR-29c targets the 3' UTR of BACE1 and downregulated the BACE1 in HEK293 cells.
Present study indicated that miR-29c was downregulated in sporadic AD brains, and it targeted the 3' UTR of BACE1, reduced the BACE1 expression, and downregulated the APPβ accumulation in vitro.
β-位点淀粉样前体蛋白裂解酶1（BACE1）被认为是治疗阿尔茨海默病（AD）的潜在靶点，AD的特征是由短β-淀粉样蛋白（APPβ）肽形成的斑块积累。最近，已证明诸如miR-29a、miR-29b-1等微小RNA与散发性AD中BACE1和APPβ的异常高水平相关。
为了确认miR-29c是否与散发性AD中BACE1的上调相关，我们首先评估了miR-29c和BACE1的表达、散发性AD脑组织中APPβ的积累，并分析了miR-29c与BACE1的相关性。然后我们确定了人神经母细胞瘤SH-SY5Y细胞中miR-29c对BACE1表达和APPβ积累的调节作用。最后我们通过荧光素酶报告基因确定了miR-29c对BACE1的3'非翻译区（UTR）的靶向作用。
结果表明，散发性AD脑内miR-29c表达下调，同时BACE1的mRNA和蛋白水平上调，且APPβ积累增加。用miR-29c模拟物转染人为提高miR-29c水平，可显著降低人神经母细胞瘤SH-SY5Y细胞中BACE1的蛋白水平和APPβ积累。进一步的荧光素酶报告基因检测表明，miR-29c靶向BACE1的3'UTR并下调HEK293细胞中的BACE1。
本研究表明，散发性AD脑内miR-29c表达下调，其靶向BACE1的3'UTR，降低BACE1表达，并在体外下调APPβ积累。
