Let-7c increases BACE2 expression by RNAa and decreases Aß production.

MicroRNAs (miRNAs) are highly conserved, non-coding transcripts that regulate gene expression in various ways. Evidence suggests that miRNAs may be a contributory factor in neurodegeneration, including Alzheimer's disease (AD), Parkinson's disease (PD), and triplet repeat disorders. In order to further understand the potential roles of miRNAs in the pathogenesis of AD, we analyzed Down syndrome (DS), a special model of AD, by using a TaqMan microRNA array and found that miRNA let-7c was up-regulated in both DS and AD. ELISA assay showed that let-7c reduced the expression level of Aß significantly. Real-time quantitative-polymerase chain reaction (RT-qPCR) was conducted to reveal that the expression level of let-7c increased dramatically in DS cells, patients with DS and mice with AD compared with normal ones respectively. Additionally, western blotting illustrated that let-7c suppressed the expression of Aß by inducing BACE2 to cut C99 and increase the content of C83/80. BACE2 expression was inhibited by let-7c and luciferase reporter gene assay revealed that let-7c increased the activity of wild-type BACE2 promoter but not 3'UTR. Furthermore, promoter analysis of BACE2 confirmed that let-7c could bind to BACE2 in the sequence between -1368 and -1347. In addition, immunoblotting assay demonstrated that let-7c induced BACE2 expression by RNAa. To the best of our knowledge, our study revealed for the first time that let-7c up-regulated BACE2 expression and decreased Aß production.

RE1 silencing transcription factor (REST) negatively regulates ALL1-fused from chromosome 1q (AF1q) gene transcription.

BACKGROUND: ALL1-fused from chromosome 1q (AF1q), originally considered as an oncogenic factor, has been implicated in neuronal development; however, its upstream regulatory mechanisms in neural system remained elusive. RESULTS: Our study showed that REST (RE1 silencing transcription factor), a key transcription factor in neurodevelopment, could down-regulate the gene expression of AF1q. The promoter assay identified a neuron-restrictive silencer element at -383 to -363 bp of human AF1q promoter. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (CHIP) confirmed the binding of REST to the NRSE in AF1q gene promoter. Additionally, the negative correlation between the expression levels of Af1q and Rest in mice neurodevelopment supported the negative regulation of AF1q by REST and the potential functions of AF1q in neurodevelopment. CONCLUSION: These results demonstrate that REST regulates AF1q gene transcription through directly binding to a NRSE at -383 to -363 bp of AF1q promoter.

Loss of membranous carcinoembryonic antigen-related cell adhesion molecule 1 expression is related to decreased relapse-free survival of hepatocellular carcinoma following liver transplantation.

BACKGROUND: Loss of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expression is an adverse prognostic factor in hepatocellular carcinoma (HCC). The purpose of this study was to investigate the expression of CEACAM1 and its effect on relapse-free survival (RFS) following liver transplantation (LT) for HCC. METHODS: Expression of CEACAM1 was immunohistochemically detected in HCC specimens from 48 patients. The relationship between CEACAM1 expression and clinicopathologic variables, as well as tumor recurrence, was further analyzed. RESULTS: Of the 48 HCC specimens, membranous CEACAM1 expression was detected in 25 specimens and cytoplasmic CEACAM1 expression was detected in 19 specimens. Four specimens had loss of CEACAM1 expression. Loss of membranous CEACAM1 expression was significantly associated with tumor size, tumor number, and serum α-fetoprotein levels (all P < 0.05). Patients with loss of membranous CEACAM1 had significantly poorer RFS than patients with membranous expression, determined via Kaplan-Meier analysis (P = 0.027). Multivariate analysis revealed that loss of membranous CEACAM1 expression might be an independent prognostic factor of RFS for HCC patients after liver transplantation (P = 0.037). CONCLUSION: Loss of membranous CEACAM1 expression in HCC was closely associated with aggressive tumor biology and might be a relapsing biomarker of HCC treated with LT.