Microenvironmentally Engineered Dental Pulp Stem Cells in Inferior Alveolar Nerve Regeneration


Inferior alveolar nerve (IAN) regeneration is essential for proper nerve sensation as well as maintaining tooth integrity and function. A promising attempt to regenerate peripheral nerve involves the cell-based therapy that can differentiate to neurons and/or secrete trophic factors to promote nerve regeneration. These processes are known to be mediated by regeneration trophic factors secreted by transplanted cells. Regenerative medicine has focused on the dental pulp stem cell (DPSC) as a ready source of multipotential adult stem cells. DPSCs are potentially well-suited to nerve regeneration given their less invasive accessibility, neural crest origin, and better regenerative qualities. The proposed project adopts an innovative and alternative approach to IAN regenerative sciences by leveraging the neurotrophic features of microenvironmentally engineered DPSCs. Our preliminary data demonstrate that adjusting the microenvironments during DPSC differentiation by hypoxia, cell-to-cell contact and modification of the receptor/intracellular signaling significantly enhanced neurotrophic capacity of the differentiated cells. The goal of this project is to define an optimal microenvironment for the neurogenic DPSC differentiation to support IAN regeneration and validate the capacity of these cells.
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Schematic representations of an Axon Investigation System (AXIS) (a). Two peripheral chambers (chamber 1 and chamber 2) and one central chamber (Chamber 3) constitute neurite outgrowth devices. (b) An AXIS cross-section: Human neurons were seeded into C3; human pulp fibroblasts were seeded into. R1, R1’, R2 and R2’. B- Schematic representations of neurite outgrowth experiments and their representative ß III tubulin staining picture and neurite trajectory plots.

Role of Complement Receptors and p38a/CEBP/BDNF in Reparative Dentinogenesis

Dental caries represents a common public health problem. The complement system, a key player of innate immunity and inflammation, is expressed and activated in the carious teeth. Very little information is available about the involvement of the complement in the tooth’s response to the common infection, caries. Moreover, inflammatory complement C5a’s role in caries-mediated dentin regeneration has received little recognition. The aim of this study is to determine the role of the complement C5a receptor-C5L2 in regulating dental pulp stem cells (DPSC) dentinogenic differentiation and in tooth dentin regeneration under an inflammatory context. We provide further evidence that p38 map kinase (p38a) plays a key role in DPSC-mediated dentinogenesis. Here, we explore ways of enhancing this odontoblastic function of DPSCs via a novel C5L2 pathway involving p38a/CEBP/BDNF signaling. We will define the role of C5L2 in the odontoblastic differentiation of DPSC and characterize the mechanism of action of C5L2 during dentinogenesis. In vivo dentin formation will be evaluated using the mouse pulp-capping/caries model combined with the C5aR, C5L2, CEBP and DSPP/p38 knockout mice. These studies will provide the basis for future potential therapeutic interventions of dentin-pulp complex regeneration and vital tooth preservation.


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Left: Hypothetical model. Silencing of C5L2 in DPSCs increases DMP1 expression to promote dentin repair. The mechanism involves removing C5L2 repression of p38-mediated signaling through C/EBP to increase DMP1 gene expression. Right: In Vivo dentin regenration in the C5a-deficient mice after dentin injury/pulp capping..(A-C) Representative Micro-CT images of upper molars obtained from C5a-deficient mice (B, C) and respective controls (C) after 4 weeks of dentin injury.



Current Funding:
NIH/NIDCR R01 2022-2026 Total $1,886,040 (PI) 
NIH/NIDCR R56 2020-2022 Total $380,000  (PI) 
NIH/NIDCR R03 2020-2023 Total $319,800  (PI) 
COD OB fund no expiration Total $250,000  (PI) .
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Seunghyuk Chung University of Illinois at Chicago