Visualization of individual cell division history in complex tissues using iCOUNT

Summary The division potential of individual stem cells and the molecular consequences of successive rounds of proliferation remain largely unknown. Here, we developed an inducible cell division counter (iCOUNT) that reports cell division events in human and mouse tissues in vitro and in vivo. Analyzing cell division histories of neural stem/progenitor cells (NSPCs) in the developing and adult brain, we show that iCOUNT can provide novel insights into stem cell behavior. Further, we use single-cell RNA sequencing (scRNA-seq) of iCOUNT-labeled NSPCs and their progenies from the developing mouse cortex and forebrain-regionalized human organoids to identify functionally relevant molecular pathways that are commonly regulated between mouse and human cells, depending on individual cell division histories. Thus, we developed a tool to characterize the molecular consequences of repeated cell divisions of stem cells that allows an analysis of the cellular principles underlying tissue formation, homeostasis, and repair.
Graphical abstract
Highlights • iCOUNT reports previous cell divisions in mouse and human cells in vitro • iCOUNT detects cell division biographies in complex mouse tissues in vivo • iCOUNT allows for the analysis of human progenitors in forebrain organoids • scRNA-seq of iCOUNT cells identifies molecular consequences of previous cell divisions
In this study, Denoth-Lippuner and colleagues developed an inducible cell division counter (iCOUNT) that reports the number of previous divisions of stem cells in vitro and in vivo. Using the iCOUNT, they identify molecular changes occurring with increased cell division history in the mouse developing brain and in human brain organoids.