Comparative Secretome Analysis of MSCs During Odontogenesis and Osteogenesis

Objectives: To understand the function of secretory proteins in odontogenesis and further the understanding of different molecular events occurring during odontogenesis and osteogenesis.
Methods: We induced the in vitro differentiation of stem cells from dental apical papilla (n=5) and mandibular bone marrow-derived stem cells (n=3) into odontoblasts and osteoblasts, respectively, and compared the expression of secretory proteins during early odontogenesis and osteogenesis using isobaric chemical tags and high-performance liquid chromatography with tandem mass spectrometry.
Results: The results revealed significant changes of at least 1.5 fold in magnitude in 139 and 203 proteins during odontogenesis and osteogenesis, respectively. Of these, 92 proteins were significantly upregulated and 47 were significantly downregulated during odontogenesis. Most of the significantly changed proteins that participated in odontogenesis showed the same trend during osteogenesis. Extracellular matrix organization proteins, calcium-binding proteins, and proteins that negatively regulate cell proliferation were increased during odontogenesis and osteogenesis, whereas neural tissue-related proteins and proteins involved in macromolecular complex assembly were decreased. Among the proteins that showed different trends of changes in odontogenesis and osteogenesis, transforming growth factor beta-2 was identified as a potential important molecule with a distinct function in the regulation of both processes.
Conclusions: Our findings suggest that the differentiation of odontoblasts and osteoblasts and their secretion of a mineralized matrix are controlled by a complex regulatory mechanism.