A Cell-permeable Fusion Protein for the Mineralization of Human Dental Pulp Stem Cells

• Published in: Journal of dental research Vol. 91; no. 1; pp. 90 - 96
• Main Authors: Suh, J.S., Kim, K.S., Lee, J.Y., Choi, Y.J., Chung, C.P., Park, Y.J.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.01.2012
• Subjects: Adipogenesis - drug effects; Analysis of Variance; Cell Differentiation - drug effects; Cell-Penetrating Peptides - biosynthesis; Cell-Penetrating Peptides - pharmacology; Dental Pulp - cytology; Endpoint Determination; Escherichia coli - genetics; Humans; Intracellular Signaling Peptides and Proteins - pharmacology; Mesenchymal Stromal Cells - cytology; Odontogenesis - drug effects; Odontogenesis - genetics; Osteogenesis - drug effects; Osteogenesis - genetics; Protamines - pharmacology; Protein Transport; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - pharmacology; Tooth Calcification - drug effects; Transduction, Genetic; cell-penetrating peptide (CPP); cell differentiation; drug delivery; transcription factor(s); human dental pulp stem cell (hDPSC); protein expression
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/0022034511424746

Human dental pulp stem cells (hDPSCs) are the only mesenchymal stem cells in pulp tissue that can differentiate into osteoblasts, odontoblasts, and adipose cells. The transcriptional co-activator with PDZ-binding motif (TAZ) protein has been reported to modulate osteogenic differentiation in mouse MSCs. Therefore, we examined whether the TAZ protein plays the same role in human pulp stem cells. In this study, TAZ was applied to cells directly with low-molecular-weight protamine (LMWP) as a cell-penetrating peptide (CPP). The LMWP-TAZ fusion proteins were expressed in an E. coli system with a pET-21b vector and efficiently transferred into hDPSCs without producing toxicity in the cells. The efficient uptake of TAZ was shown by Western blot with an anti-TAZ antibody, fluorescence-activated cell sorting, and confocal microscopy in live cells. The delivered TAZ protein increased osteogenic differentiation, as confirmed by alkaline phosphatase (ALP) staining, RT-PCR, and Western blotting. In addition, TAZ also inhibited adipogenic differentiation, regulating peroxisome proliferator-activated receptor-γ (PPAR-γ), lipoprotein lipase (LPL), and adipocyte fatty acid-binding protein (aP2) mRNA levels. These in vitro studies suggest that cell-permeable TAZ may be used as a specific regulator of hard-tissue differentiation.