Cyclic nucleotide phosphodiesterase activity in stem cells of human periodontal ligament (PDL-MSCs) before and after osteogenic induction

Objective. The aim of this work was to evaluate both the level of endogenous cyclic nucleotides cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cAMP) and phosphodiesterase activity in mesenchymal stem cells (MSCs) before and during the osteogenic induction. Study Design. Samples were organized into control (nondifferentiated) and test groups which were analyzed at 3 different time points: 1, 2, and 4 weeks. Periodontal ligament MSCs were isolated and then expanded in an MSCM medium while cyclic nucleotide levels and phosphodiesterase activity were assessed. Results. cAMP and cGMP levels were markedly higher in the first week than in the following stages. Similarly, PDE activity increased during the first week and reached the peak in the second week. Conclusions. This work validates that cAMP, cGMP, and PDE activities are important factors in the first phase of the osteogenic induction of a human stem cell.