Perinatal S-Adenosylmethionine Supplementation Represses PSEN1 Expression by the Cellular Epigenetic Memory of CpG and Non-CpG Methylation in Adult TgCRD8 Mice

Abstract

DNA methylation, the main epigenetic modification regulating gene expression, plays a role in the pathophysiology of neurodegeneration. Previous evidence indicates that 5′-flanking hypomethylation of PSEN1, a gene involved in the amyloidogenic pathway in Alzheimer’s disease (AD), boosts the AD-like phenotype in transgenic TgCRND8 mice. Supplementation with S-adenosylmethionine (SAM), the methyl donor in the DNA methylation reactions, reverts the pathological phenotype. Several studies indicate that epigenetic signatures, driving the shift between normal and diseased aging, can be acquired during the first stages of life, even in utero, and manifest phenotypically later on in life. Therefore, we decided to test whether SAM supplementation during the perinatal period (i.e., supplementing the mothers from mating to weaning) could exert a protective role towards AD-like symptom manifestation. We therefore compared the effect of post-weaning vs. perinatal SAM treatment in TgCRND8 mice by assessing PSEN1 methylation and expression and the development of amyloid plaques. We found that short-term perinatal supplementation was as effective as the longer post-weaning supplementation in repressing PSEN1 expression and amyloid deposition in adult mice. These results highlight the importance of epigenetic memory and methyl donor availability during early life to promote healthy aging and stress the functional role of non-CpG methylation.

Amyloidogenic and Neuroinflammatory Molecular Pathways Are Contrasted Using Menaquinone 4 (MK4) and Reduced Menaquinone 7 (MK7R) in Association with Increased DNA Methylation in SK-N-BE Neuroblastoma Cell Line

“…This aspect is of course intriguing and deserving of further investigation in the future, probably through “omic” analysis at the mRNA and protein levels. Another interesting aspect of the methylation data is that, as previously showed, the presence of methyl groups at non-CpG cytosine moieties (the so-called “non-CpG”, or “CpH”, methylation) is detectable at discrete levels when analyzed through bisulfite primers that are unbiased versus CpA, CpC and CpT methylation [ 51 ]. Moreover, non-CpG methylation appears to also be functional since it is modulated according to gene expression.…”

“…Analyses were performed in triplicate for each sample. cDNA levels were normalized to the β-actin control and presented as the fold increase over the control sample, as previously described [ 51 ]. The RNA extraction on columns was carried out using the automated tool QIAcube (Qiagen, Milan, Italy).…”

“…The real-time analysis for assessing the expression of target genes was performed on a CFX apparatus using the iTaq Universal SYBR Green Supermix (both from Bio-Rad, Milan, Italy), as previously described [ 51 ]. Sequences and characteristics of the primers used in the PCR reactions are reported in Table 1 .…”

“…SK-NB-E cells were treated for 72 h with 50 µM of MK4 and MK7R and then lysed for 30 min on ice in RIPA buffer (50 mM Tris, 150 mM NaCl, 1 mM EGTA, 1 mM EDTA, 1 mM sodium deoxycholate, 1% NP40), supplemented with PMSF (200 μM), leupeptin (1 μM), pepstatin A (1 μM) and calpain inhibitor I (5 μM), all from Merck (Milan, Italy). A total of 60 μg of each protein extract was used for electrophoresis with NuPAGE Bis-Tris precasted 10% or 7% (based on the molecular weight under investigation), run in NuPAGE MOPS buffer (Invitrogen, Milan, Italy) under reducing conditions and transferred onto nitrocellulose membranes, as previously described [ 51 ]. The primary antibodies used are listed in the table below ( Table 2 ).…”

The Impact of Oxidative Stress on the Epigenetics of Fetal Alcohol Spectrum Disorders

“…These modifications include DNA methylation, histone modification, and non-coding ribonucleic acid (RNA) molecules, collectively influencing the accessibility of genes to the cellular machinery responsible for transcription [30,31]. The impact of epigenetics extends far beyond the individual organism, as these marks can be passed down through generations, heralding the era of transgenerational inheritance [4,32,33]. This phenomenon challenges the conventional view that genetic information flows strictly through the DNA sequence, introducing a dynamic layer of complexity to our understanding of heredity.…”