Tabula sapiens, most comprehensive human cell atlas

In a recent study published in the journal Science, researchers created an atlas termed the Tabula sapiens for over 400 distinct cell types of humans. Several aspects of human physiology were revealed by the atlas, such as how different types of cells splice genes differently.

The Tabula sapiens has information on around 500,000 human cells spread in over 400 cell types based on the measured amount of the messenger ribonucleic acid (mRNA) molecules in each cell harvested from approximately 24 human organs.

The issue with the current approaches was that they used organs from multiple donors and processed them using different protocols, which often hindered attaining good results. Additionally, differences in genetic makeup and age of donors, environmental conditions, and epigenetic factors hampered the results.

Study: The Tabula Sapiens: A multiple-organ, single-cell transcriptomic atlas of humans. Image Credit: ktsdesign / ShutterstockStudy: The Tabula Sapiens: A multiple-organ, single-cell transcriptomic atlas of humans. Image Credit: ktsdesign / Shutterstock

In the present study, researchers explored the molecular composition of various cell types within humans by transcriptional and proteomic approaches. They generated a molecular atlas of more than 400 different types of cells, which showed their tissue-level distribution and variations in gene expression.

They performed coordinated single-cell transcriptome analyses on live cells obtained from multiple tissues of a single donor. Next, they processed and analyzed these specimens and performed quality control (QC) filtering to fetch 483,152 cells. Overall, there were 59 specimens and a dataset of 264,824 immune cells, 31,691 endothelial cells (ECs), and 82,478 stromal cells.

The dataset covered messenger ribonucleic acid (mRNA) transcripts of each cell, including those processed by the cell’s splicing machinery. The researchers mapped the relationships between T cells distributed across body tissues by assembling T cell receptor sequences from a single donor. Furthermore, they classified the immunoglobulin (Ig) expression of each B cell in the dataset.

The researchers also determined the cycling index for each cell type to identify actively proliferating cells against cells in post-mitotic phases. This is how the Tabula Sapiens gathered dynamic information from the data at a single time point for each donor

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