Barrachina Marta, Moreno Jesús, Juvés Salvador, Moreno Dolores, Olivé Montse, Ferrer Isidre
Institut de Neuropatologia, Servei Anatomia Patològica, IDIBELL-Hospital Universitari de Bellvitge, carrer Feixa Llarga sn, 08907 L'Hospitalet de Llobregat, Spain.
Am J Pathol. 2007 Oct;171(4):1312-23. doi: 10.2353/ajpath.2007.070520. Epub 2007 Sep 6.
Myotilinopathy is a subgroup of myofibrillar myopathies caused by mutations in the myotilin gene in which there is aggregation of abnormal cytoskeletal proteins and ubiquitin. We report here on the accumulation of neuron-related proteins such as ubiquitin carboxy-terminal hydrolase L1 (UCHL1), synaptosomal-associated protein 25, synaptophysin, and alpha-internexin in aberrant protein aggregates in myotilinopathy. We have determined that the neuron-restrictive silencer factor (NRSF)/RE1 silencing transcription factor (REST), a transcription factor expressed in non-neuronal tissues repressing the expression of several neuronal genes, is reduced in myotilinopathies. Moreover, NRSF transfection reduces UCHL1, synaptosomal-associated protein 25, synaptophysin, and alpha-internexin mRNA levels in DMS53 cells, whereas short interferring NRSF transfection increases UCHL1 and synaptophysin mRNA levels in U87-MG cells. Chromatin immunoprecipitation assays have shown that NRSF interacts with the UCHL1 promoter in U87-MG and HeLa cells. In silico analysis of the UCHL1 gene promoter sequence using the MatInspector software has predicted three potential neuron-restrictive silencer elements (NRSEs): NRSE1 located in the complementary DNA chain and NRSE2 and NRSE3 in intron 1, in the coding and complementary chains, respectively. Together, these findings show, for the first time, abnormal regulation of NRSF/REST as a mechanism associated with the aberrant expression of selected neuron-related proteins, which in turn accumulate in abnormal protein aggregates, in myotilinopathy.
肌联蛋白病是肌原纤维肌病的一个亚组，由肌联蛋白基因突变引起，其中存在异常细胞骨架蛋白和泛素的聚集。我们在此报告在肌联蛋白病的异常蛋白聚集体中存在神经元相关蛋白的积累，如泛素羧基末端水解酶L1（UCHL1）、突触体相关蛋白25、突触素和α-中间丝蛋白。我们已经确定，神经元限制性沉默因子（NRSF）/RE1沉默转录因子（REST），一种在非神经元组织中表达的转录因子，可抑制几种神经元基因的表达，在肌联蛋白病中减少。此外，NRSF转染降低了DMS53细胞中UCHL1、突触体相关蛋白25、突触素和α-中间丝蛋白的mRNA水平，而短干扰NRSF转染增加了U87-MG细胞中UCHL1和突触素的mRNA水平。染色质免疫沉淀分析表明，NRSF在U87-MG和HeLa细胞中与UCHL1启动子相互作用。使用MatInspector软件对UCHL1基因启动子序列进行的计算机分析预测了三个潜在的神经元限制性沉默元件（NRSE）：NRSE1位于互补DNA链中，NRSE2和NRSE3分别位于内含子1中，分别位于编码链和互补链中。总之，这些发现首次表明，NRSF/REST的异常调节是一种与肌联蛋白病中选定的神经元相关蛋白异常表达相关的机制，这些蛋白进而在异常蛋白聚集体中积累。
