Scientists have revealed the difference between a stem cell and other blood vessel cells using gene-sequencing technology.

The senior author said the findings provided evidence of how stem cells express genes that allow them to be identified within a blood vessel. "Until now, we couldn't accurately say how a stem cell differed from the other cells without preconceived ideas," the senior author said. "We hypothesized that stem cells expressed genes that could separate them from other cells inside the blood vessel."

The authors performed the study and looked at every single cell in the largest artery, the aorta, and identified the genes expressed by each cell through sequencing.

"This allowed us to examine every cell without any bias or pre-conceived idea of whether it is a stem cell or not," the lead author said.

The study used single-cell RNA sequencing to look at the gene expression of each cell and group common cells together into separate populations.

Authors show that two transcriptionally distinct endothelial populations exist within the aorta and, using two independent trajectory analysis methods, confirm that they represent transitioning cells rather than discrete cell types. Gene co-expression analysis revealed crucial regulatory networks underlying each population, including significant metabolic gene networks in progenitor cells.

"We used specialised algorithms to group cells that express similar sets of genes into clusters," another explained. "What we found is that these stem cells form little groups within the blood vessel and that is how you differentiate them from other cells."

Using mitochondrial activity assays and phenotyping, the authors confirm that endovascular progenitors display higher mitochondrial content compared to differentiated endothelial cells. The identities of these populations were further validated against bulk RNA sequencing (RNA-seq) data obtained from normal and tumor-derived vasculature.

Knowing the exact profile of a stem cell will help researchers develop new treatment options for conditions like skin cancer, heart attacks and wound healing.

"This will have an impact on how we treat conditions which are the result of dysfunctional blood vessel behavior," the senior author said. "We know that if you can target these stem cells, then you can reduce blood vessel formation and potentially stop diseases like skin cancer metastasis."

Professor Khosrotehrani had hypothesised this method of stem cell identification and said these findings provided answers to scientific debate.

https://www.cell.com/cell-reports/fulltext/S2211-1247(19)30582-0

http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fsingle-cell-transcriptio&filter=22