Age-Related Gene Expression
Genetic Changes and Aging
In recent years, scientists have studied the gene expression changes during aging to better understand the genetic and biological mechanisms involved in this process. Aging is a natural and inevitable process but also a risk factor for many diseases, such as neurodegenerative diseases and cancer.
Gene Expression Change
Most biological and cellular mechanisms are regulated by our genes, which encode for proteins, the actors in the biological mechanisms. One of the mechanisms of regulation of the presence of proteins in a cell is through gene expression change. When a protein is not used or necessary in a particular cell, the gene encoding for this protein will not be expressed or will express at a low level. When a protein is needed in a particular cell, the gene will be expressed at higher level to induce the production of this protein in this particular cell.
The gene expression changes in cells indicate biological needs and adaptation. In aging cells this also indicates a need to protect the cells from the aging process and manage the cellular changes more effectively. To date the gene expression changes observed in aging tissues are subtle and probably vary from one tissue to another. The challenge of scientists is to identify the most important ones involved in the aging process.
Several Studies Aim to identify Gene Expression Changes Related to Aging
Scientists have attempted to compare the gene expression changes in young and old specimens obtained from humans and rodents. A group of scientists from Harvard Medical School (Boston, US) and the Escola Superior de Biotecnologia of Porto (Portugal) has compiled and analyzed data published in 12 different experiments from mice, rats and humans. The study is published by George M. Church and colleagues in the scientific journal Bioinformatics under the title "Meta-Analysis of age-related gene expression profiles identifies common signature of aging" (Bioinformatics, vol. 25, n. 07, p. 875-881, 2009).
The team of scientists has developed a new statistical method of analyzing gene expression changes (also named gene expression profiles) presented in different studies. Such a study is called meta-analysis and allows comparing, compiling and homogenizing different studies. The advantage of such an analysis is to increase the number of studied samples and identify the more reproducible results.
Apolipoprotein D Protects Against Aging
In this new study, the authors revealed more than 71 genes consistently regulated with age, and independently of sample species (human or rodent) or tissue source. Among these genes, the most significant changes were observed in the Apolipoprotein D gene expression. Apolipoprotein D has previously been identified as a protein able to extend lifespan in flies. The fact that Apoliproprotein D is also regulated in human and rodent aging samples suggest that this gene is involved in a mechanism protecting cells from aging.
Cellular Energy and Immune Response are Associated with Aging
The other genes identified in this study are known to be involved in the immune and inflammatory response and generation of the cellular energy, which are two mechanisms already suspected to be associated with aging. This study confirms those previous observations but also indicates that these mechanisms occurred in different tissues and different species. Also it remains to determine which genes and mechanisms are a response to aging and participate in cellular degeneration and those which protect against cellular degeneration.
Aging
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