Scientists have found that adding adenosine to growing pluripotent stem cells encourages the cells to turn into osteoblasts, cells that build bone. Previously, this process was difficult and required many different chemicals. The findings will help researchers make regenerative medicine more accessible for people who need it, including patients with serious injuries and bone disorders. The details are in a paper just published in the journal Science Advances.
Pluripotent stem cells are capable of growing into any type of adult cell. This makes them incredibly valuable in medicine since they can replace faulty cells, help grow new tissue, or even synthesize organs. It’s difficult to direct proper stem cell differentiation, however, and the process is often complicated and expensive. When something goes wrong, leading some cells to differentiate improperly, teratomas can develop. Teratomas are tumors consisting of different types of tissue.
In a previous study, the team had investigated how stem cells differentiate into osteoblasts. They found that the cells would take up calcium phosphate, resulting in ATP production. The ATP molecules would break down, releasing an adenosine signal and triggering differentiation.
The researchers dosed stem cell cultures with adenosine. The stem cells differentiated into osteoblasts without any other signals. The new osteoblasts were fully functional and began producing calcified bone matrix. The team transplanted the cells into mice with bone defects. They were able to successfully treat the mice and the animals grew new bone tissue without the formation of teratomas.
There are a host of injuries and diseases that can be treated with bone-building osteoblasts. Pluripotent stem cells are capable of differentiating into these cells but current methods are intricate and costly. This study shows that the addition of a single naturally-occurring molecule, adenosine, is enough to encourage stem cells to develop into osteoblasts. Furthermore, the cells can be used to treat bone defects without the risk of teratoma formation. The team is already continuing their research to improve their understanding of how adenosine signals stem cells to differentiate into osteoblasts.
Heemin Kang et al. Small molecule–driven direct conversion of human pluripotent stem cells into functional osteoblasts. Science Advances (2016).