The environment may influence the cell fate decision of mesenchymal stem cells, which are important for making and repairing skeletal tissues such as cartilage, bone, and dental tissues, according to the University of Southern California (USC) Herman Ostrow School of Dentistry.
Shuo Chen, PhD, a postdoctoral scholar and research associate at the USC Center for Craniofacial Molecular Biology, has discovered that a particular kind of cell known as Runx2 coordinates the transition from mesenchymal stem cell to transit amplifying cell.
This is responsible for the bulk of tissue homeostasis, the researchers said, controlling the incisor growth rate in the mice they were studying. Importantly, they added, Runx2 regulates many parts of the stem cell environment.
Fueled by stem cells, rodent incisors never stop growing throughout the animal’s life, providing an opportunity to study how stem cells work. Single-cell RNA sequencing revealed that Runx2+ cells are strategically positioned to support the stem cell niche environment.
Also, the cells control how quickly the mouse incisors grew. When the Runx2 gene was deleted, the mice developed shorter incisor teeth. All of these findings add up to a broader knowledge of how the whole dental development and tissue homeostasis system functions, the researchers said.
“This knowledge is crucial for understanding the function of stem cells and forms the foundation for stem cell supported tissue regeneration,” said associate dean of research Yang Chai, PhD, DDS, director of the Center for Craniofacial Molecular Biology at USC and coauthor of the study.
One of the biggest challenges in the dental clinic is treating tooth injuries, said Chen.
“Stem cells may be a good choice for tooth regeneration in the future,” Chen said. “It is very important to get a better understanding of the biological behavior and niche environment of stem cells before we use them in the clinic.”
The researchers plan to keep investigating the niche, neighborhood environment of mesenchymal stem cells. They also plan to design a tooth injury model to test how well the Runx2 cells work during tooth regeneration. So far, niche cells for mesenchymal stem cells have yet to be well defined, Chen said, which inspires him to continue the work.
“That is why I decided to be a scientist and focus on stem cell biology,” Chen said.
The study, “Runx2+ Niche Cells Maintain Incisor Mesenchymal Tissue Homeostasis Through IGF Signaling,” was published by Cell Reports.