Gigi Yip
Pronouns: she/they
Research Mentor(s): Yuji Mishina
Research Mentor School/College/Department: Biological and Material Sciences / Dentistry
Program:
Authors: Gigi Yip, Yuji Mishina, Hiroki Ueharu
Session: Session 4: 1:40 pm – 2:30 pm
Poster: 106
Abstract
Temporomandibular Joint (TMJ) Disorder (TMD) is prevalent in 5% – 12% of the adult population and twice as common in women than men, resulting in difficulty opening one’s mouth. Bone morphogenetic proteins (BMPs) play important roles in the formation of bone, cartilage, and other non-osteogenic processes. Hence, when BMP signaling is enhanced, disorders with bone formation have been discovered. Therefore, this study will focus on the effects of enhanced BMP signaling in neural crest derived-condyle cells, multipotent cells specifically aimed at developing the condyle, at the TMJ. By analyzing sagittal tissue images after cross-breeding P0-Cre and Wnt1-Cre mice with caBMPr1a mice, we can visualize the effects of augmented BMP signaling at the condyle of the TMJ. P0-Cre and Wnt1-Cre are the most efficient transgenic mouse lines that can detect neural crest cells, while constitutively activated Bmpr1a (caBmpr1a) allows for BMP signaling to operate without the presence of BMP ligands. Our preliminary data of P0-Cre or Wnt1-Cre crossed with caBmpr1a mice showed that augmentation of BMP signaling in cranial neural crest cells develop abnormal condyles at P17. Based on our published data (Hayano et al., Development, 2015 and Ueharu et al., JBMR Plus, 2023), we focused on BMP-induced cell death at the condyle. Cells were stained with TUNEL and DAPI in order to detect the total number of cells and the number of cells that went through apoptosis. TUNEL stains for cell apoptosis, while DAPI stains for the nuclei in cells. After analyzing sagittal sections of the TMJ condyles, it was discovered that Wnt1-Cre;caBmpr1a mice had 19.4% (P>0.05 compared to control mice, P<0.05 compared to P0-Cre;caBmpr1a) of cells in apoptosis, while P0-Cre;caBmpr1a mice had 4.65% (P<0.05 compared to Wnt1-Cre;caBmpr1a and P>0.05 compared to control) and control mice had 1.63% (P>0.05 compared to both mutant mice). Therefore, after examining these results, it can be concluded that enhanced BMP signaling leads to cell apoptosis of neural crest derived-condyle cells in the TMJ condyles. Cell apoptosis could be a potential indicator to TMD, therefore future research should focus on pharmaceutical treatments to prevent cell deaths at the TMJ.
