| First Author | Nishida D | Year | 2021 |
| Journal | Sci Rep | Volume | 11 |
| Issue | 1 | Pages | 4575 |
| PubMed ID | 33633362 | Mgi Jnum | J:303856 |
| Mgi Id | MGI:6512709 | Doi | 10.1038/s41598-021-84354-y |
| Citation | Nishida D, et al. (2021) RANKL/OPG ratio regulates odontoclastogenesis in damaged dental pulp. Sci Rep 11(1):4575 |
| abstractText | Bone-resorbing osteoclasts are regulated by the relative ratio of the differentiation factor, receptor activator NF-kappa B ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG). Dental tissue-localized-resorbing cells called odontoclasts have regulatory factors considered as identical to those of osteoclasts; however, it is still unclear whether the RANKL/OPG ratio is a key factor for odontoclast regulation in dental pulp. Here, we showed that odontoclast regulators, macrophage colony-stimulating factor-1, RANKL, and OPG were detectable in mouse pulp of molars, but OPG was dominantly expressed. High OPG expression was expected to have a negative regulatory effect on odontoclastogenesis; however, odontoclasts were not detected in the dental pulp of OPG-deficient (KO) mice. In contrast, damage induced odontoclast-like cells were seen in wild-type pulp tissues, with their number significantly increased in OPG-KO mice. Relative ratio of RANKL/OPG in the damaged pulp was significantly higher than in undamaged control pulp. Pulp damages enhanced hypoxia inducible factor-1alpha and -2alpha, reported to increase RANKL or decrease OPG. These results reveal that the relative ratio of RANKL/OPG is significant to pulpal odontoclastogenesis, and that OPG expression is not required for maintenance of pulp homeostasis, but protects pulp from odontoclastogenesis caused by damages. |
