The Aging Fly Cell Atlas, a Map of Gene Expression Changes with Age
Gathering data on the fine details of aging proceeds a good deal more rapidly than making use of that data. The new Aging Fly Cell Atlas is a representative example of the many large databases being generated using modern omics techniques. It provides details of gene expression changes over the course of aging for different cell types in the fly body. Taking this data and tying it to specific causes and consequences of aging remains a sizable undertaking, a work in progress in its earliest stages. Progress towards therapies to treat aging cannot wait for the greater understanding of the fine details of aging that lies decades ahead at this point; it is important that we forge ahead now, building on what is known of the causes of aging. If one can in fact address a cause of aging, then the best way to learn how that cause affects gene expression profiles is to treat it.
Researchers have published the first Aging Fly Cell Atlas (AFCA), a detailed characterization of the aging process in 163 distinct cell types in the laboratory fruit fly. Their in-depth analysis revealed that different cell types in the body age differently, each cell type following a process involving cell type-specific patterns. As the flies aged, the researchers took samples when the animals were 30, 50 and 70 days old (the latter is equivalent to an 80-year-old person). At each time point, the team conducted single-nucleus RNA sequencing to analyze gene expression changes in individual cells in different organs and compared the results to those of young flies (5 days old).
The team examined four different aging features: cell composition changes, number of differentially expressed genes, change in the number of expressed genes and decline of cell identity. They found that as flies age, these features change as a group according to cell type-specific patterns. Aging impacts cellular composition across the whole fly. Fat body cells were among the cell types that increased in number the most, while muscle cells decreased the most. Neurons, however, did not show major changes in the number of cells during the fruit fly's life. In addition, the analysis of the genes expressed by different cell types in time revealed that fat cells show the largest difference between the number of genes expressed in young versus old fruit flies. The researchers also found that about 80% of all the cell types analyzed decreased the number of genes expressed, and 20% increased this number.
"A critical observation of this study is that cell type-specific aging patterns in cells can be used to gauge biological age, that is the relative aging status of an organism, independent of its chronological age. This will provide further insight into factors, such as diets, drugs and diseases, that may change the aging trajectory and hence make an organism 'younger' or 'older' than its chronological age."
Link: https://www.bcm.edu/news/close-up-on-aging-reveals-different-cells-age-at-different-pace