DNA methylation in the NCAPH2/LMF2 promoter region is associated with hippocampal atrophy in Alzheimer's disease and amnesic mild cognitive impairment patients
NEUROSCIENCE LETTERS
Authors: Shinagawa, Shunichiro; Kobayashi, Nobuyuki; Nagata, Tomoyuki; Kusaka, Akira; Yamada, Hisashi; Kondo, Kazuhiro; Nakayama, Kazuhiko
Abstract
Several studies have noted an effect of DNA methylation on the pathogenesis of Alzheimer's disease (AD). We have already reported that DNA methylation levels in the NCAPH2/LMF2 promoter region can be a useful biomarker for the diagnosis of AD and amnesic mild cognitive impairment (aMCI). However, there is still uncertainty about the mechanism by which NCAPH2/LMF2 methylation affects the pathogenesis of AD and aMCI. In this study, we investigated relationships between NCAPH2/LMF2 methylation and other factors. AD (n=30) and aMCI (n=28) subjects were included in this study. NCAPH2/LMF2 methylation levels were measured by pyrosequencing. Correlations between methylation levels and other factors including age at onset, sex, duration of disease, education, mini-mental state examination (MMSE) and frontal assessment battery (FAB) scores, APOE genotype, degree of hippocampal atrophy, and total brain atrophy were measured. Degrees of hippocampal atrophy and total brain atrophy were measured by VSRAD (Voxel-Based Specific Regional Analysis System for Alzheimer's Disease). Regression analysis revealed that only hippocampal atrophy according to VSRAD is a significant dependent variable correlated with NCAPH2/LMF2 methylation levels. Our results suggest that DNA methylation in the NCAPH2/LMF2 promoter region is associated with hippocampal atrophy through apoptosis. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
Condensin II subunit NCAPH2 associates with shelterin protein TRF1 and is required for telomere stability
JOURNAL OF CELLULAR PHYSIOLOGY
Authors: Wallace, Heather A.; Rana, Vibhuti; Nguyen, Huy Q.; Bosco, Giovanni
Abstract
Condensin II subunits are known to be expressed and localized to interphase nuclei of eukaryotic cells. Although some studies have shown that condensin II likely exerts axial compaction forces, organizes chromosome territories, and has possible transcriptional modulatory functions, the full range of condensin II interphase activities are not known. In particular, it is not known if condensin II interphase activities are generally genome-wide or if they have additional local activities unique to specific chromosomal structures such as telomeres. Here, we find that NCAPH2 interacts with TRF1 and these two proteins co-localize at telomeres. Depletion of NCAPH2 leads to ATR-dependent accumulation of 53BP1 and gamma H2AX DNA damage foci, including damage specific to telomeres. Furthermore, depletion of NCAPH2 results in a fragile telomere phenotype and apparent sister-telomere fusions only days after NCAPH2 depletion. Taken together these observations suggest that NCAPH2 promotes telomere stability, possibly through a direct interaction with the TRF1 shelterin component, and prevents telomere dysfunction resulting from impaired DNA replication. Because proper telomere function is essential for chromosome integrity these observations reveal a previously unappreciated function for NCAPH2 in ensuring genome and telomere stability.