The essential role of Mkx in periodontal ligament on the metabolism of alveolar bone and cementum

Lisa Yagasaki; Tomoki Chiba; Ryota Kurimoto; Mitsuyo Nakajima; Takanori Iwata; Hiroshi Asahara

Regenerative Therapy (Mar 2024)

The essential role of Mkx in periodontal ligament on the metabolism of alveolar bone and cementum

Lisa Yagasaki,
Tomoki Chiba,
Ryota Kurimoto,
Mitsuyo Nakajima,
Takanori Iwata,
Hiroshi Asahara

Affiliations

Lisa Yagasaki: Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
Tomoki Chiba: Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
Ryota Kurimoto: Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
Mitsuyo Nakajima: Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
Takanori Iwata: Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Corresponding author.
Hiroshi Asahara: Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan; Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Corresponding author. Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.

Journal volume & issue: Vol. 25
pp. 186 – 193

Abstract

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Introduction: The periodontium is a connective tissue which consists of periodontal ligament, alveolar bone, cementum and gingiva. Periodontal ligament (PDL) is a specialized connective tissue that connects the cementum – coating the surface of the tooth – to the alveolar bone. Mohawk homeobox (Mkx) is a transcription factor that is expressed in PDL, that is known to play a vital role in the development and homeostasis of PDL. A detailed functional analysis of Mkx in the periodontal ligament for alveolar bone and cementum metabolism has not yet been conducted. Materials and methods: Alveolar bone height, bone mineral density (BMD) and bone volume fractions (Bone volume/Total volume: BV/TV) were measured and analyzed using micro-computed tomography (Micro-CT) and 3DBon on 7-week-old male wild-type (WT) (Mkx+/+) (n = 10) and Mkx-knockout (Mkx−/−) (n = 6) rats. Hematoxylin and Eosin (H&E), tartrate-resistant acid phosphatase (TRAP), alkaline phosphatase (ALP) and Masson Trichrome staining were performed on 5, 6, and 7-week-old Mkx+/+ and Mkx−/− rats. Cementum surface area and the number of TRAP-positive osteoclasts/mm were quantified, measured, and compared for 5,6 and 7-week-old Mkx+/+ and Mkx−/− rats (n = 3 each). Results: The level of alveolar bone height was significantly higher in Mkx−/− rats than in Mkx+/+ rats. On the other hand, there was significantly less BMD in Mkx−/− alveolar bone. A significant increase in cellular cementum could be observed as early as 5 weeks in Mkx−/− rats when compared with Mkx+/+ rats of the same age. More TRAP-positive osteoclasts were observed in Mkx−/− rats. Conclusion: Our findings further reveal the essential roles of Mkx in the homeostasis of the periodontal tissue. Mkx was found to contribute to bone and cementum metabolism and may be essential to the prevention of diseases such as periodontitis, and could show potential in regenerative treatments.

Published in Regenerative Therapy

ISSN: 2352-3204 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Medicine: Medicine (General); Science: Biology (General): Cytology
Website: http://www.journals.elsevier.com/regenerative-therapy/

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