Epigenetics and lifestyle
A group of scientists from the Diabetes Center of Lund University in Sweden summarized the latest findings of studies conducted in the field of epigenetics related to obesity and type 2 diabetes.
The importance of diet
Scientists conducted several interventional studies of the effect of nutrition on the epigenome, where participants followed different diets.
A high-fat diet in five days changed the activity of genes and DNA methylation in skeletal muscles and adipose tissue.
In another study, participants ate cupcakes with either saturated or polyunsaturated fats for seven weeks. All participants gained the same weight, but those who ate cupcakes with saturated fats suffered more from the accumulation of visceral fat in the liver.
Visceral obesity can cause diabetes and cardiovascular diseases. It was also noted that it is much easier to change the methylation process by eating a high-fat meal than to reverse these changes with a well-balanced diet.
Physical activity
Regular physical activity protects and prevents the development of type 2 diabetes. Exercise has a beneficial effect not only on glucose homeostasis and the energy balance of the whole body, but also on the immune system.
A 2013 study showed that during exercise, the activity of genes that affect the metabolism of fatty acids in adipose tissue increases.
Exercise has a clear effect on DNA methylation in both genes and tissues.
Aging
The aging process is characterized by a significant change in the epigenome, in which genes lose or acquire new methyl groups.
Obesity seems to affect age-related epigenetic changes, which provides a molecular link between aging and obesity.
The significance of heredity
Since methylation occurs in certain parts of DNA, hereditary changes may affect the possibility of attaching methyl groups to genes.
A study of pancreatic islets has shown that half of the gene sequences that are associated with type 2 diabetes create or delete sites where methylation can occur, and some of them are related to the ability of cells to secrete insulin.
Is the epigenome inherited?
There is a hypothesis that epigenetic inheritance contributes to evolution. The epigenome adapts faster to changes in our lifestyle than our genes through mutations. At the embryonic stage, the most active epigenetic reprogramming occurs. The authors of the article describe that what a woman is exposed to during pregnancy affects not only her and her child, but also her grandchildren by affecting the reproductive cells of the embryo.
Recently, more and more research has been devoted to the transfer of epigenetic information from father to child. For example, the epigenome of spermatozoa is influenced by environmental factors, which is likely to have an impact on the next generation.
A 2016 study showed that the sperm methylome in obese men who underwent bariatric surgery changed after surgery.
Another study showed that exercise can reprogram the sperm methylome, but it has not yet been established how these changes are inherited and beneficial for offspring.
New epigenetic drugs
In the future, it may be possible to use epigenetic biomarkers to predict an increased risk of developing obesity and type 2 diabetes.
There are already drugs that affect DNA methylation and histone modifications and, according to research results. improve insulin secretion.
Studying the epigenome
Currently, the DNA methylation pattern is being studied using bisulfite sequencing, where more than 80 percent of CpG islands (cytosine and guanine separated by phosphate binding these two nucleotides) are analyzed. CpG islands are high-density CpG sites devoid of methylation found on the promoters of most human genes. In addition to DNA methylation, the epigenome also includes various histone modifications and small non-coding RNAs.
The article by Ling et al Epigenetics in Human Obesity and Type 2 Diabetes is published in the journal Cell.
Elena Panasyuk, portal "Eternal youth" http://vechnayamolodost.ru / based on the materials of Lund University: How lifestyle affects our genes: review.