The role of neurotrophic factors in dental pulp stem cells

Authors

Kamille Mercado, University of the Pacific
Nan (Tori) Xiao, University of the PacificFollow

Lead Author Affiliation

Dental Surgery Program

Introduction/Context/Diagnosis

Neurotrophic factors are growth factors that can nourish neurons and promote neuron survival and regeneration. These factors include NGF, BDNF, NTs and the glial cell derived neurotrophic factors (GDNF) family. Besides GDNF, the family also includes neurturin (NRTN), artemin (ARTN) and persephin (PSPN). Dental pulp stem cells (DPSCs) are multipotent mesenchymal cells that can differentiate into different cells originally derived from ectoderm, mesoderm and endoderm. Researches indicate that human DPSCs are able to differentiate into neuron, blood vessel, dentin, bone and adipose tissue under appropriate conditions. These properties make DPSCs a promising resource for stem cell therapy. This study aims to investigate the role of neurotrophic factors in the DPSCs. The hypothesis is that neurotrophic factors promote the DPSC proliferation, and may also be involved in DPSC migration and differentiation.

Methods/Treatment Plan

Human DPSCs cells were a gift from Dr. Songtao Shi, Chair and Professor of the Department of Anatomy & Cell Biology at University of Pennsylvania, School of Dental Medicine. DPSC mRNA was extracted from samples of five different patients, and reverse transcripted into cDNA. Primer sequences were designed with Primer3web online software. Using Quantitative PCR, the expression of the neurotrophic family members and receptors in the DPSC were determined. Quantitative PCR was performed on the cDNA samples using a 7900HT detection system (Applied Biosystems). All PCR reactions were carried out in triplicate. Quantification of the samples was calculated with the threshold cycle by ΔΔCt method. Immunofluorescent staining images were acquired using a Leica TCS SPE confocal microscope. Over a 24-hour period, scratch assays with increasing concentrations of PSPN neutrophic factor were produced. Scratch assay images were acquired using a Leica DMiL inverted microscope.

Results/Outcome

The GDNF family of neurotrophic factors and receptors were expressed in the cytoplasm of the DPSCs. Recombinant hPSPN, which was most highly expressed along with its receptor in these samples, appeared to increase DPSC migration.

Significance/Conclusions

Preliminary data indicated that neurotrophic factor PSPN has a dose dependent effect on the DPSCs’ migration. Thus, the GDNF family of neutrophic factors appears to have a chemotactic effect that draws stem cells to a certain site. The future direction is to investigate the effect of different neurotrophic factors on DPSC behavior, and the downstream signaling pathways involved in the process. This work will be important to understand the molecular mechanism of the dental pulp regeneration post trauma and pulpectomy. This will also shed light on the potential application of neurotrophic factors and DPSCs in other adult tissue regeneration, including wound healing.

Comments/Acknowledgements

This work was supported by grants from the University of the Pacific, Arthur A. Dugoni School of Dentistry. We thank Dr. Songtao Shi (University of Pennsylvania) for sharing the DPSC cells.

Location

University of the Pacific, Dugoni Dental School, San Francisco, CA

Format

Poster

Poster Session

Senior Research Presentations