Secretomes from dental-derived mesenchymal stem cells for tissue regeneration

The role of secretome from dental-derived mesenchymal stem cell (MSC) as potential biological mediator for tissue regeneration has not been fully explored. Thus, this project aimed to evaluate this potential with the objectives of 1)to evaluate the effect of hypoxia incubation on stem cells proliferation and growth factors production and genes, 2) To evaluate the variabilities in the secretome production, 3) To explore the proteomic profiles of the secretomes and 4) To evaluate the effect of the collected secretome on pre-osteoblast cells proliferation, Alkaline Phosphatase (ALP) activity and migration. Rat bone marrow mesenchymal stem cells (BMSCs), periodontal ligament stem cells (PDLSCs) and dental pulp stem cells (DPSCs) were harvested and tested for stem cell markers, osteogenic and adipogenic differentiation, and various gene expression for growth factors and osteogenic potential. The cells were cultured in serum free media for 2 or 3 days and incubated in normal oxygen concentration (21%) or hypoxia (2%) before the conditioned media (CM) that contained the secretomes were collected. The CM were used for ELISA of VEGF, TGF-β1 and IGF-1, proteomic profiles via mass spectrometry and used in MTT, ALP and migration assays. PDLSCs have distinctive pattern of cell growth and lower osteogenic potential compared to BMSCs and DPSCs. The three stem cells produced VEGF and TGF-β1. IGF-1 was only detected in PDLSCs’ CM. Hypoxia incubation promoted cell proliferation and increased VEGF and IGF-1 in the secretome. Different collection days and filtration of the CM could alter the protein content of secretome. Although proteomic profiles of PDLSC, DPSC and BMSC secretomes indicated diverse and complex mixtures of proteins, the effect of three sources of MSC secretomes produced almost similar effect on pre-osteoblast cell proliferation, ALP activity and cell migration. As a conclusion, secretomes of PDLSCs and DPSCs have a potential to be the biological mediators for tissue regeneration due to various protein content that are known important for tissue regeneration. Further research is needed to strengthen these findings