Department of Pharmaceutical Sciences and Center for Drug Discovery, School of Pharmacy, Northeastern University, Boston, MA, USA.
Guangxi Collaborative Innovation Center for Biomedicine, Guangxi Medical University, Nanning, Guangxi, China.
J Cell Mol Med. 2017 Nov;21(11):2974-2984. doi: 10.1111/jcmm.13209. Epub 2017 May 19.
Huntington's disease (HD) is caused by a genetically mutated huntingtin (mHtt) protein with expanded polyQ stretch, which impairs cytosolic sequestration of the repressor element-1 silencing transcription factor (REST), resulting in excessive nuclear REST and subsequent repression of neuronal genes. We recently demonstrated that REST undergoes extensive, context-dependent alternative splicing, of which exon-3 skipping (∆E )-a common event in human and nonhuman primates-causes loss of a motif critical for REST nuclear targeting. This study aimed to determine whether ∆E can be targeted to reduce nuclear REST and rescue neuronal gene expression in mouse striatal-derived, mHtt-expressing STHdh cells-a well-established cellular model of HD. We designed two morpholino antisense oligos (ASOs) targeting the splice sites of Rest E and examined their effects on ∆E , nuclear Rest accumulation and Rest-controlled gene expression in STHdh cells. We found that (1) the ASOs treatment significantly induced ∆E , reduced nuclear Rest, and rescued transcription and/or mis-splicing of specific neuronal genes (e.g. Syn1 and Stmn2) in STHdh cells; and (2) the ASOs-induced transcriptional regulation was dependent on ∆E induction and mimicked by siRNA-mediated knock-down of Rest expression. Our findings demonstrate modulation of nuclear REST by ∆E and its potential as a new therapeutic target for HD and provide new insights into environmental regulation of genome function and pathogenesis of HD. As ∆E is modulated by cellular signalling and linked to various types of cancer, we anticipate that ∆E contributes to environmentally tuned REST function and may have a broad range of clinical implications.
亨廷顿病（HD）是由突变的亨廷顿蛋白（mHtt）引起的，其含有扩展的 polyQ 延伸，该蛋白可损害细胞质中沉默转录因子元件-1 抑制因子（REST）的隔离，导致核内 REST 过度积聚，并随后抑制神经元基因的表达。我们最近证实，REST 经历广泛的、依赖于上下文的选择性剪接，其中外显子 3 跳跃（∆E）-在人类和非人类灵长类动物中常见的事件-导致丧失核 REST 靶向的关键基序。本研究旨在确定是否可以靶向 ∆E 以减少核内 REST 并挽救表达 mHtt 的 STHdh 细胞（一种成熟的 HD 细胞模型）中的神经元基因表达。我们设计了两种针对 Rest E 剪接位点的莫洛尼反义寡核苷酸（ASO），并研究了它们对 STHdh 细胞中 ∆E、核内 Rest 积累和受 Rest 控制的基因表达的影响。我们发现：（1）ASO 处理显著诱导 ∆E、减少核内 Rest，并挽救 STHdh 细胞中转录和/或特定神经元基因（如 Syn1 和 Stmn2）的异常剪接；（2）ASO 诱导的转录调控依赖于 ∆E 的诱导，且可以通过 siRNA 介导的 Rest 表达敲低来模拟。我们的研究结果表明，通过 ∆E 调节核内 REST 及其作为 HD 新治疗靶点的潜力，并为环境调节基因组功能和 HD 发病机制提供了新的见解。由于 ∆E 受到细胞信号的调节，与多种类型的癌症有关，我们预计 ∆E 有助于环境调节的 REST 功能，并可能具有广泛的临床意义。
