Department of Physiology and Biophysics, State University of New York at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA.
Department of Physiology and Biophysics, State University of New York at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA.
Neurobiol Dis. 2023 Aug;184:106192. doi: 10.1016/j.nbd.2023.106192. Epub 2023 Jun 10.
Epigenetic aberrations are suggested to play an important role in transcriptional alterations in Alzheimer's disease (AD). One of the key mechanisms of epigenetic regulation of gene expression is through the dynamic organization of chromatin structure via the master genome architecture protein, CCCTC-binding factor (CTCF). By forming chromatin loops, CTCF can influence gene transcription in a complex manner. To find out whether genome-wide DNA binding sites for CTCF are altered in AD, we compared CTCF chromatin immunoprecipitation sequencing (ChIP-Seq) data from frontal cortex of human AD patients and normal controls (n = 9 pairs, all females). We have revealed that CTCF-binding affinity on many genes is significantly reduced in AD patients, and these genes are enriched in synaptic organization, cell adhesion, and actin cytoskeleton, including synaptic scaffolding molecules and receptors, such as SHANK2, HOMER1, NRXN1, CNTNAP2 and GRIN2A, and protocadherin (PCDH) and cadherin (CDH) family members. By comparing transcriptomic data from AD patients, we have discovered that many of the synaptic and adhesion genes with reduced CTCF binding in AD are significantly reduced in their mRNA expression. Moreover, a significant overlap of genes with the diminished CTCF binding and the reduced H3K27ac is identified in AD, with the common genes enriched in synaptic organization. These data suggest that the CTCF-controlled 3D chromatin organization is perturbed in AD, which may be linked to the diminished expression of target genes, probably through changes in histone modification.
表观遗传异常被认为在阿尔茨海默病 (AD) 的转录改变中发挥重要作用。表观遗传调控基因表达的关键机制之一是通过主基因组结构蛋白 CCCTC 结合因子 (CTCF) 动态组织染色质结构。CTCF 通过形成染色质环,可以以复杂的方式影响基因转录。为了确定 AD 中是否存在全基因组 CTCF 的 DNA 结合位点改变,我们比较了来自 AD 患者和正常对照者前额叶皮层的 CTCF 染色质免疫沉淀测序 (ChIP-Seq) 数据(n=9 对,均为女性)。我们发现,AD 患者许多基因的 CTCF 结合亲和力显著降低,这些基因富集在突触组织、细胞黏附和肌动蛋白细胞骨架中,包括突触支架分子和受体,如 SHANK2、HOMER1、NRXN1、CNTNAP2 和 GRIN2A,以及原钙黏蛋白 (PCDH) 和钙黏蛋白 (CDH) 家族成员。通过比较 AD 患者的转录组数据,我们发现,AD 中许多 CTCF 结合减少的突触和黏附基因的 mRNA 表达显著降低。此外,在 AD 中还鉴定到了 CTCF 结合减少和 H3K27ac 减少的基因的显著重叠,共同基因富集在突触组织中。这些数据表明,AD 中 CTCF 控制的 3D 染色质组织受到干扰,这可能与靶基因表达的减少有关,可能是通过组蛋白修饰的改变。