Genetic Background Influences Behavior and Responses to Epigenetic Changes Induced by a Methyl-Donor Diet

With recent strides in epigenetics, mainstream media informs the public that we can “beat our genes” by, for instance, changing our diet. Genetics, however, still plays a role in phenotype. Folate and other methyl-donor pathway components are widely supplemented due to their ability to prevent neural tube defects during prenatal development. In addition to vitamins, these compounds are also added to commercial flour, energy drinks, and other supplements. Several lines of evidence suggest that these supplements act through epigenetic mechanisms, including altering DNA methylation. Increasing evidence suggests potential deleterious effects of excessive folate. Given the benefits of these compounds, risk statements must be made with caution. We hypothesized that excess dietary methyl donors during development might contribute to the apparent rise in neurobehavioral disorders such as attention-deficit disorder (ADD), obsessive compulsive disorder (OCD) and autism spectrum disorders (ASD). To test these hypotheses, we used wildderived Peromyscus (deer mice) stocks. Peromyscus are common native North American mammals and exhibit great natural variation. We used two species that are known to differ in physiology, epigenetic control, and behavior. Specifically, P. maniculatus (BW stock) are susceptible to repetitive behaviors and are more aggressive in a neutral space. P. polionotus (PO stock) exhibit greater sociality and less repetitive behavior and are better able to buffer stress. In addition the two species can form fertile hybrids in BW female x PO male crosses thus enabling genetic basis of such phenotypes to be determined. Here we have determined genetic mechanisms by which behaviors differ between BW and PO. Additionally, we discovered behavioral differences in a naturally occurring wide band agouti (ANb) deer mouse (on a BW background) when compared to BW. Using the same methyl-donor diet used in the classic mouse agouti viable yellow allele (Avy), we demonstrated that the effects of the diet are different across three genotypes (while two genotypes, BW and ANb, are very similar). These effects included various adult defects, mortality, and behavioral changes. Here we also present data from additional behavioral parameters in both PO and BW animals developmentally exposed to the methyldonor diet. We also present data showing paternal genotype affects DNA methylation status at the imprinting control region of the Peg10/Sgce locus. This work was funded by NIH P40 OD 010961 and by a SPARC Grant from the Office of the VP for Research at the University of South Carolina

Peromyscus as a Mammalian Epigenetic Model

Deer mice (Peromyscus) offer an opportunity for studying the effects of natural genetic/epigenetic variation with several advantages over other mammalian models. These advantages include the ability to study natural genetic variation and behaviors not present in other models. Moreover, their life histories in diverse habitats are well studied. Peromyscus resources include genome sequencing in progress, a nascent genetic map, and >90,000 ESTs. Here we review epigenetic studies and relevant areas of research involving Peromyscus models. These include differences in epigenetic control between species and substance effects on behavior. We also present new data on the epigenetic effects of diet on coat-color using a Peromyscus model of agouti overexpression. We suggest that in terms of tying natural genetic variants with environmental effects in producing specific epigenetic effects, Peromyscus models have a great potential

Proceedings of the 13th annual conference of INEBRIA

CITATION: Watson, R., et al. 2016. Proceedings of the 13th annual conference of INEBRIA. Addiction Science & Clinical Practice, 11:13, doi:10.1186/s13722-016-0062-9.The original publication is available at https://ascpjournal.biomedcentral.comENGLISH SUMMARY : Meeting abstracts.https://ascpjournal.biomedcentral.com/articles/10.1186/s13722-016-0062-9Publisher's versio

Acute high folic acid treatment in SH-SY5Y cells with and without MTHFR function leads to gene expression changes in epigenetic modifying enzymes, changes in epigenetic marks, and changes in dendritic spine densities.

Epigenetics are known to be involved in various disorders, including neurobiological disorders like autism. Dietary factors such as folic acid can affect epigenetic marks using methylenetetrahydrofolate reductase (MTHFR) to metabolize folic acid to a one-carbon methyl group. As MTHFR mutations are frequent, it is curious as to whether excess folic acid, with or without functioning MTHFR, could affect gene expression, epigenetics, and neuromorphology. Here, we investigated gene expression and activity of epigenetic modifying enzymes, genome-wide DNA methylation, histone 3 modifications, and dendritic spine densities in SH-SY5Y cells with or without a knockdown of MTHFR and with or without an excess of folic acid. We found alterations to gene expression of epigenetic modifying enzymes, including those associated with disorders like autism. Grouping the epigenetic modifying enzymes by function indicated that gene expression was widely affected for genes that code for enzymes affecting DNA methylation, histone acetylation, histone methylation, histone phosphorylation, and histone ubiquitination when excess folic acid treatment occurred with or without the knockdown of MTHFR. MTHFR was significantly reduced upon excess folic acid treatment whether MTHFR was knocked-down or not. Further, methyl-CpG binding protein 2 expression was significantly decreased with excess folic acid treatment with and without proper MTHFR expression. Global DNA methylation decreased due to the knockdown alone while global hydroxymethylated DNA increased due to the knockdown alone. TET2 expression significantly increased with the MTHFR knockdown alone. Excess folic acid alone induced a decrease in TET3 expression. Excess folic acid induced an increase in dendritic spines without the MTHFR knockdown, but folic acid induced a decrease in dendritic spines when MTHFR was knocked-down. The knockdown alone also increased the dendritic spines significantly. Histone 3 acetylation at lysine 18 was significantly increased when excess folic acid was applied to cells with the MTHFR knockdown, as was histone 3 phosphorylation at serine 10. Broadly, our results indicate that excess folic acid, even with functioning MTHFR, could have detrimental effects on cells

What family support specialists do: examining service delivery.

This study describes services provided by family support specialists (FSS), peer advocates in programs for children with serious psychiatric conditions, to delineate differences between recommended components of FSS services and services actually provided. An analysis of qualitative interview and observational data and quantitative survey data from 63 staff at 21 mental health programs in New York identified that FSS and other staff have generally similar ideas about FSS services, and that these perceptions of activities are generally congruent with what FSS actually did. Implications of findings are discussed in the context of developing competencies and quality indicators for FSS

Pleiotropic Effects of a Methyl Donor Diet in a Novel Animal Model

<div><p>Folate and other methyl-donor pathway components are widely supplemented due to their ability to prevent prenatal neural tube defects. Several lines of evidence suggest that these supplements act through epigenetic mechanisms (e.g. altering DNA methylation). Primary among these are the experiments on the mouse viable yellow allele of the agouti locus (A^vy). In the A^vy allele, an Intracisternal A-particle retroelement has inserted into the genome adjacent to the agouti gene and is preferentially methylated. To further test these effects, we tested the same diet used in the A^vy studies on wild-derived <i>Peromyscus maniculatus</i>, a native North American rodent. We collected tissues from neonatal offspring whose parents were fed the high-methyl donor diet as well as controls. In addition, we assayed coat-color of a natural variant (wide-band agouti = A^Nb) that overexpresses agouti as a phenotypic biomarker. Our data indicate that these dietary components affected agouti protein production, despite the lack of a retroelement at this locus. Surprisingly, the methyl-donor diet was associated with defects (e.g. ovarian cysts, cataracts) and increased mortality. We also assessed the effects of the diet on behavior: We scored animals in open field and social interaction tests. We observed significant increases in female repetitive behaviors. Thus these data add to a growing number of studies that suggest that these ubiquitously added nutrients may be a human health concern.</p></div

Mortality & abnormalities observed in methyl vs. control diet animals.

<p>Mortality & abnormalities observed in methyl vs. control diet animals.</p

Weight distributions of methyl-diet vs control diet animals.

<p>We weighed 68 experimental animals (40 ♀ & 28 ♂) and 40 controls (12 ♀ & 18 ♂) at six months of age. The difference between female experimental & female control (ctrl) was significant (p<0.05; t-test), male averages were not significant. However, there were two methyl-diet males that were much larger than the control population.</p

Representative abnormalities observed in methyl diet animals.

<p>(A) Hemorrhagic ovarian cyst in a methyl diet female. (B) Normal diet animal’s ribcage, heart, and lungs (left) compared to one methyl diet animal’s ribcage, heart and lungs; note abnormalities in size and shape of lungs and heart. (C) Cataracts were visible in the left eye of some animals. (D) Left and right testes from a control diet male (top) and a methyl diet male (bottom). Chi squared tests suggest significant size differences between right and left testes in these three methyl diet males.</p