背景:21三体,人类21号染色体(HSA21)的额外拷贝,导致大多数唐氏综合征(DS)病例。患有DS的人在中年后不可避免地发展为阿尔茨海默病(AD)神经病理学表型,包括淀粉样斑块和tau神经原纤维缠结。泛素特异性肽酶25(USP25),由位于HSA21上的USP25基因编码,是一种去泛素化酶,在DS和AD的发病机制中起着重要作用。然而,USP25的规定尚不清楚。
目的:我们旨在确定神经元细胞中特异性蛋白1(SP1)对USP25的调节及其在淀粉样蛋白生成中的潜在作用。
方法:通过SMART-RACE和双荧光素酶测定鉴定转录起始位点和启动子活性。通过EMSA检查功能性SP1响应元件。通过RT-PCR和免疫印迹检查USP25表达。应用学生t检验或单因素方差分析或统计分析。
结果:鉴定了人USP25基因的转录起始位点。揭示了人USP25基因中的三个功能性SP1响应元件。SP1促进USP25转录和随后的USP25蛋白表达,而SP1抑制显著降低非神经元和神经元细胞中的USP25表达。此外,SP1抑制显著降低淀粉样蛋白生成。
结论:我们证明转录因子SP1调节USP25基因表达,与淀粉样蛋白生成有关。这表明SP1信号可能在USP25调节中起重要作用,并有助于USP25介导的DS和AD发病机制。
Trisomy 21, an extra copy of human chromosome 21 (HSA21), causes most Down\'s syndrome (DS) cases. Individuals with DS inevitably develop Alzheimer\'s disease (AD) neuropathological phenotypes after middle age including amyloid plaques and tau neurofibrillary tangles. Ubiquitin Specific Peptidase 25 (USP25), encoding by USP25 gene located on HSA21, is a deubiquitinating enzyme, which plays an important role in both DS and AD pathogenesis. However, the regulation of USP25 remains unclear.
We aimed to determine the regulation of USP25 by specificity protein 1 (SP1) in neuronal cells and its potential role in amyloidogenesis.
The transcription start site and promoter activity was identified by SMART-RACE and Dual-luciferase assay. Functional SP1-responsive elements were examined by EMSA. USP25 expression was examined by RT-PCR and immunoblotting. Student\'s t-test or one-way ANOVA were applied or statistical analysis.
The transcription start site of human USP25 gene was identified. Three functional SP1 responsive elements in human USP25 gene were revealed. SP1 promotes USP25 transcription and subsequent USP25 protein expression, while SP1 inhibition significantly reduces USP25 expression in both non-neuronal and neuronal cells. Moreover, SP1 inhibition dramatically reduces amyloidogenesis.
We demonstrates that transcription factor SP1 regulates USP25 gene expression, which associates with amyloidogenesis. It suggests that SP1 signaling may play an important role in USP25 regulation and contribute to USP25-mediated DS and AD pathogenesis.