Harnessing PRX1 expressing cells for endogenous periodontal regeneration

Periodontal disease (PD) is the sixth most prevalent health condition in the World. It leads to periodontal tissue loss, tooth loss, and is linked to other high prevalence diseases such as diabetes, cardiovascular diseases, and pulmonary infections. For these reasons, PD has been identified as a global public health issue and

represents a significant economic burden for the US, causing an estimated loss of $154.06B. Unfortunately, due to the complexity of the periodontal anatomy, composed of bone, cementum, and periodontal ligament (PDL), currently available periodontal therapies have limited regenerative efficacy. Given the ability of stem cells to

differentiate in various phenotypes, periodontal ligament stem cells (PDLSCs) may be able to regenerate this complex anatomical structure and may therefore represent the most promising therapeutic tool. However, the lack of biological and molecular knowledge about the PDLSCs and the lack of strategies to harness them for

periodontal regeneration limit our ability to develop novel and more effective therapies. We found that expression of PRX1 (or PRRX1), a transcription factor highly expressed during limb and craniofacial development, identifies a population of PDLSCs in the mouse periodontium (mouse PRX1- expressing Periodontal Cells, hereafter mPRX1-PCs). These cells are required for and directly contribute to

periodontal regeneration. Now, using single cell RNA-sequencing we have identified the human homologs of the mPRX1-PCs (hPRX1-PCs). These cells, located in the human periodontal ligament, present with a molecular signature of stem cells, and are identified by highly specific surface markers. With these findings and with the final goal of developing more effective alternatives to the current

periodontal regeneration therapies, in this research project we aim at 1) identifying a specific set of cell surface markers that allows for the isolation and full characterization of the hPRX1-PCs; 2) developing a novel harnessing strategy that leverages on the PDLSCc to induce complete periodontal regeneration; and 3) augmenting the

stem cell potency of the PDLSCc to regenerate oversize periodontal defects. These studies may lead to the development of novel therapies that will endogenously stimulate periodontal regeneration while circumventing the need for transplantation of biomaterials or osteogenic tissue.