Serotonin in stem cell based-dental repair and bone formation: A review.

Genetic and pharmacological studies provided evidence that serotonin (5-HT) is an important signaling molecule for the development and the maintenance of mineralized tissues. However, how 5-HT takes part to the homeostasis of teeth and bone remains elusive. In the dental field, a major breakthrough comes from the identification of 5-HT but also dopamine (DA) as "damage" signals necessary for stem cell-based tooth repair. Pulpal stem cells express the overall functions of 5-HT and DA neurons including a definite set of functional 5-HT/DA receptors that render cells responsive for circulating bioamines. Upon tooth injury, activated platelets release bulks of 5-HT/DA that mobilize pulpal stem cells for natural dental repair. The contribution of 5-HT to bone metabolism is more documented with description of both anabolic and resorptive effects. By controlling the tissue-non specific alkaline phosphatase (TNAP), 5-HT2B receptors exert an anabolic function and a pivotal role in mineralization processes. Increasing our understanding of the role of 5-HT receptors in bone metabolism may pave the road for the development of therapeutic strategies towards skeletal-associated pathologies and ectopic calcification.