iTRAQ-Based Proteomic Analysis Exploring the Influence of Hypoxia on the Proteome of Dental Pulp Stem Cells under 3D Culture.

Hypoxic preconditioning is commonly applied to enhance mesenchymal stem cells (MSCs) therapeutic effect before transplantation. Elucidating the effect of hypoxic preconditioning would be beneficial for improved application. However, the influence of hypoxia on dental tissue derived MSCs cultured in 3D was unknown. Thus, the present study is to investigate gene expression and proteome of dental pulp stem cells (DPSCs) after hypoxic preconditioning. DPSCs were isolated, cultured in a 3D system under the normoxic and hypoxic conditions. The gene expression was examined with reverse transcription polymerase chain reaction, and the proteome was analyzed using iTRAQ-based mass spectrometry. The expressions of HIF-1α, VEGFA, KDR at mRNA level was upregulated while BMP-2 was downregulated. Two thousand one hundred and fifteen proteins were identified and 57 proteins exhibited significant differences after hypoxic preconditioning (30 up-regulated, 27 down-regulated). Bioinformatic analysis revealed the majority of up-regulated proteins are involved in cellular process, angiogenesis, protein binding and transport, regulation of response to stimulus, metabolic processes, and immune response. Increased IL-6 and decreased TGF-1β protein expression under hypoxic condition were verified by ELISA. Hypoxic preconditioning partly affected the gene and protein expression in DPSCs under 3D culture and may enhance the efficacy of MSCs transplantation.