ACVR1is essential for periodontium development and promotes alveolar bone formation

Publication date: Available online 31 July 2018

Source: Archives of Oral Biology

Author(s): Xue Zhang, Qilin Liu, Huan Zhao, Yue Hu, Cangwei Liu, Guangxing Yan, Daowei Li, Yuji Mishina, Ce Shi, Hongchen Sun

Abstract

Objective

To explore the role of a BMP type I receptor (ACVR1) in regulating periodontium development, Acvr1 was conditionally disrupted in Osterix-expressing cells.

Methods

Mandibles from both control (Acvr1 fx/+; Osterix-Cre (+)/(-)) and cKO (Acvr1 fx/-; Osterix-Cre (+)/(-)) mice at postnatal day 21 (PN21) were scanned by micro-CT, followed by decalcification and histological observations. Distribution and levels of differentiation markers of fibroblasts, osteoblasts and cementocytes in the periodontium were detected by immunohistochemical (IHC) staining.

Results

Micro-CT results showed that bone mass and mineral density of the alveolar bones in the cKO mice were lower than those in the controls. Histomorphometry within the alveolar bones revealed that the lower bone mass observed in the cKO mice was caused by increased numbers and resorption activities of osteoclasts. The markers for osteoblast differentiation, Col I and DMP1, were reduced and the signals of the RANKL/OPG ratio were increased in the alveolar bones of the cKO mice compared to those of the control mice. The periodontal ligament in the cKO mice exhibited disorganized collagen fibers with weaker signals of Col I and periostin. However, there was no difference in terms of the cellular cementum between the two groups.

Conclusion

ACVR1 is essential for normal periodontium development. Osteoblast ACVR1 negatively regulates osteoclast differentiation in association with the RANKL/OPG axis and thus promotes alveolar bone formation.

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