A diet that has been significantly supplemented with or deficient in methionine, an essential amino acid found in eggs, meat, and seafood, has a bearing on gene expression, as well as genes that have altered chromatin. The coiled fibers formed up of DNA and proteins that form chromosomes in cells.
Methionine is a biochemical process involving the addition of a methyl radical to the DNA molecule. This is an epigenetic variation, resulting in an expression profile of the genes that define an individual characteristic, which can be repeated in cell division and transmitted to descendants, although they are not identical to alterations in the DNA sequence (genotype). At present, scientists are analyzing the relationship between methylation and disease.
Researchers used mice for a methionine-deficient or methionine-supplemented diet to investigate the epigenetic effects of liver cells. Cells then extracted from their livers for molecular analysis.
The fourth study, published by the Nutrigenomics Research Group at the University of Sao Paulos Ribeirao Preto School of Pharmaceutical Sciences in Brazil, is based on data from the PhD research of Alexandre Ferro Aissa, who was supported by FAPESP via a doctortoral scholarship and a scholarship for a study abroad.
Igor Pogribny, a researcher at the National Center for Toxicological Research, is a nonprofit organization that works with the United States Food and Drug Administration. Pogribny has pioneered research on methylation and the role of methionine, focusing on hepatic steatosis, which is currently considered an epidemic. Pogribny himself suggested Aissa investigate the effects of methionine on liver cells.
Previous findings from the FCFRP-USP group, such as one previously reported in 2014, showed that dietary methionine deficiency and supplementation may cause molecular abnormalities associated with hispatic steatosis, including altered gene expression, which causes lipid accumulation in the liver. According to Aissa, this discovery did not necessarily reveal how this happened.
These findings provide a deeper understanding of the effects of diet on gene regulation, including the effects of diet on microRNAs (or miRNAs, small RNA molecules that do not provide the origin of proteins but regulate the functioning of genes).
diets with low methionine levels, especially those deficient in the amino acid, can lead to dysregulation of several microRNAs that may impact liver homeostasis, according to Aissa.
For Antunes, the precise contribution of this study is a list of several biomarkers associated with a tissue alteration, such as genes with an altered methylation pattern and the microRNAs linked to this process. All these tools can be used to improve diagnosis and prognosis.
The group still has a large amount of information to share. For example, female mice were involved in their reproductive period, which will be possible to discover the implications of methionine deficiency and supplementation on their descendants. Besides, they have also identified methionine metabolism and its association with the development of cardiac disease, including epigenetic mechanisms.