Gu Jeffrey, Barrera Julio, Yun Young, Murphy Susan K, Beach Thomas G, Woltjer Randy L, Serrano Geidy E, Kantor Boris, Chiba-Falek Ornit
Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, Durham, NC, United States.
Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, United States.
Front Neurosci. 2021 Apr 28;15:652226. doi: 10.3389/fnins.2021.652226. eCollection 2021.
Parkinson's disease (PD) and dementia with Lewy body (DLB) are the most common synucleinopathies. gene is a major genetic risk factor for these diseases group, and dysregulation of its expression has been implicated in the genetic etiologies of several synucleinopathies. DNA methylation at CpG island (CGI) within intron 1 has been suggested as a regulatory mechanism of expression, and changes in methylation levels at this region were associated with PD and DLB. However, the role of DNA methylation in the regulation of expression in a cell-type specific manner and its contribution to the pathogenesis of PD and DLB remain poorly understood, and the data are conflicting. Here, we employed a bisulfite pyrosequencing technique to profile the DNA methylation across intron 1 CGI in PD and DLB compared to age- and sex-matched normal control subjects. We analyzed homogenates of bulk frozen frontal cortex samples and a subset of neuronal and glia nuclei sorted by the fluorescence-activated nuclei sorting (FANS) method. Bulk brain tissues showed no significant difference in the overall DNA methylation across intron 1 CGI region between the neuropathological groups. Sorted neuronal nuclei from PD frontal cortex showed significant lower levels of DNA methylation at this region compared to normal controls, but no differences between DLB and control, while sorted glia nuclei exhibited trends of decreased overall DNA methylation in DLB only. In conclusion, our data suggested disease-dependent cell-type specific differential DNA methylation within intron 1 CGI. These changes may affect dysregulation that presumably mediates disease-specific risk. Our results can be translated into the development of the intron 1 CGI region as an attractive therapeutics target for gene therapy in patients who suffer from synucleinopathies due to dysregulation.
帕金森病（PD）和路易体痴呆（DLB）是最常见的α-突触核蛋白病。基因是这些疾病组的主要遗传风险因素，其表达失调与几种α-突触核蛋白病的遗传病因有关。内含子1内CpG岛（CGI）处的DNA甲基化被认为是该基因表达的一种调节机制，该区域甲基化水平的变化与PD和DLB相关。然而，DNA甲基化以细胞类型特异性方式调节该基因表达的作用及其对PD和DLB发病机制的贡献仍知之甚少，且数据相互矛盾。在此，我们采用亚硫酸氢盐焦磷酸测序技术，与年龄和性别匹配的正常对照受试者相比，分析PD和DLB患者中α-突触核蛋白基因内含子1 CGI区域的DNA甲基化情况。我们分析了大量冷冻额叶皮质样本的匀浆以及通过荧光激活核分选（FANS）方法分选的神经元和胶质细胞核亚群。在神经病理学组之间，大量脑组织在内含子1 CGI区域的总体DNA甲基化方面没有显著差异。与正常对照相比，PD额叶皮质中经分选的神经元核在该区域的DNA甲基化水平显著降低，但DLB与对照组之间无差异，而经分选的胶质细胞核仅在DLB中呈现总体DNA甲基化降低的趋势。总之，我们的数据表明内含子1 CGI内存在疾病依赖性的细胞类型特异性差异DNA甲基化。这些变化可能影响α-突触核蛋白基因失调，推测其介导疾病特异性风险。我们的结果可转化为将内含子1 CGI区域开发为因α-突触核蛋白基因失调而患α-突触核蛋白病患者基因治疗的有吸引力的治疗靶点。
