Tabula Muris Senis: A Single Cell Transcriptome Database by Tissue and Age in Mice
Researchers here announce the publication of a database of 300,000 single cell transcriptomes across cell types, tissues, and ages in mice. This and similar vaults of data will no doubt keep factions within the research community busy for years to come, refining their efforts to produce useful, verified biomarkers of aging. The most important thing that can be achieved with such biomarkers of aging is the comparatively rapid assessment of different approaches to rejuvenation. At present all too much of the field is focused on projects that cannot possible do all that much good in terms of lengthening healthy life span. Redirecting researchers to better approaches much earlier in the development process is a desirable outcome.
Aging leads to the decline of major organs and is the main risk factor for many diseases, including cancer, cardiovascular and neurodegenerative diseases. While previous studies have highlighted different hallmarks of the aging process, the underlying molecular and cellular mechanisms remain unclear. To gain a better understanding of these mechanisms, the Tabula Muris Consortium created the single-cell transcriptomic dataset, called Tabula Muris Senis (TMS). The TMS contains over 300,000 annotated cells from 23 tissues and organs of male and female mice. "These cells were collected from mice of diverse ages, making the data a tremendous opportunity to study the genetic basis of aging across different tissues and cell types."
The original TMS study mainly explored the cell-centric effects of aging, aiming to characterise changes in the composition of cell types within different tissues. In the current gene-centric study, researchers focused on changes in gene expression that occur during the aging process across different cell types. Using the TMS data, they identified aging-dependent genes in 76 cell types from 23 tissues. They then characterised the aging behaviours of these genes that were both shared among all cell types ('globally') and specific to different tissue cells.
"We found that the cell-centric and gene-centric perspectives of the previous and current studies are complementary, as gene expression can change within the same cell type during aging, even if the composition of cells in the tissue does not vary over time. The identification of many shared aging genes suggests that there is a coordinated global aging behaviour in mice." The team then used this coordinated activity to develop a single-cell aging score based on the global aging genes. This new high-resolution aging score revealed that different tissue-cell types in the same animal can have a different aging status, shedding light on the diverse aging process across different types of cells.