How the immune system ages
Chromosomes are cellular structures located in the nucleus of a cell, consisting of DNA helices, in which information about the structure of proteins necessary for this cell to perform its function is encoded. This information is read from DNA strands, and then reproduced as a chain of amino acids that make up a protein.
A group of scientists from the University of Connecticut and the Jackson Laboratory of Genetic Medicine has proved that chromosomes lose their ability to fully perform their functions with age. This is due to the twisting and compaction of DNA strands, which complicates and sometimes makes it impossible to transcribe (read) encoded information. Thus, some proteins are not synthesized in sufficient volume or are not synthesized at all, and this can have consequences in the form of a tendency to diseases.
Geriatric specialist George Kuchel, immunologist Jacques Banchereau and their group were engaged in the identification of specific DNA sites that lose function with aging. The large volume and variety of data even required the invention of new methods of analysis.
The study involved 75 healthy people aged 22-40 years and 26 healthy people aged 65 years and older. A blood sample was taken from each subject. A group of researchers isolated immune cells (peripheral blood mononuclear lymphocytes, as well as monocytes, B-lymphocytes and T-lymphocytes) from the blood to assess age-related changes in the activity of genes responsible for their synthesis.
A combined analysis of the availability of chromatin, which carries information about the studied immune cells, and a transcriptome (the result of reading from a DNA strand) revealed activity in a group of young people and its decrease with age. Inhibition of IL7R interleukin genes and IL-7 signaling pathway genes was also detected, which in the future can be used as biomarkers of aging. These genes are necessary for the work of CD8+ T-lymphocytes, which store information about previous infections and form secondary immunity.
Thus, human aging is associated with changes occurring in chromosomes. The data obtained allow a deeper understanding of the mechanisms of age–related immunodeficiency, they can be used to assess the response of an elderly organism to vaccination - the authors of the article are currently investigating a pneumococcal vaccine in this light.
Article by D. Ucar et al. The chromatin accessibility signature of human immune aging stems from CD8+ T cells is published in The Journal of Experimental Medicine.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Connecticut: Aged DNA May Activate Genes Differently.