David Andreas Hilbert1, Svenja Memmert2,3, Jana Marciniak2, Andreas Jäger2. 1. Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Welschnonnenstr. 17, 53111, Bonn, Germany. d.hilbert@uni-bonn.de. 2. Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany. 3. Section of Experimental Dento-Maxillo-Facial Medicine, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany.
Abstract
PURPOSE: The circadian clock plays an important role in many physiological states and pathologies. The significance of its core genes in bone formation and tooth development has already been demonstrated. However, regulation of these genes and their influence on periodontal and bone remodeling in periodontal ligament (PDL) fibroblasts remains to be elucidated. Our hypothesis was that the circadian clock influences markers for periodontal and bone remodeling and therefore orthodontic tooth movement itself. MATERIALS AND METHODS: Human PDL fibroblasts were cultured and synchronized in circadian rhythms with the help of a dexamethasone shock. Cells were harvested at 4 h intervals. Reverse transcription and quantitative RT PCR (real time polymerase chain reaction) were performed to assess the mRNA levels of the clock genes ARNTL, CLOCK1, PER1, and PER2. Subsequently, mRNA expression of important marker genes for periodontal and bone remodeling, OPG, RANKL, OCN, OPN, RUNX2, COL1A1, IL1β, KI67, and POSTN, were examined at time points of ARNTL amplitude expression. RESULTS: Gene expression of core clock genes varied over 48 h in accordance with the circadian rhythm. Functional markers, except KI67, showed significant differences at time points of maximum fluctuation especially of ARNTL. CONCLUSIONS: PDL fibroblasts express circadian clock genes. Our results suggest that genes associated with bone and periodontal remodeling are influenced by the circadian rhythm. Further research will have to refine the understanding of this influence for orthodontic treatment.
PURPOSE: The circadian clock plays an important role in many physiological states and pathologies. The significance of its core genes in bone formation and tooth development has already been demonstrated. However, regulation of these genes and their influence on periodontal and bone remodeling in periodontal ligament (PDL) fibroblasts remains to be elucidated. Our hypothesis was that the circadian clock influences markers for periodontal and bone remodeling and therefore orthodontic tooth movement itself. MATERIALS AND METHODS:Human PDL fibroblasts were cultured and synchronized in circadian rhythms with the help of a dexamethasoneshock. Cells were harvested at 4 h intervals. Reverse transcription and quantitative RT PCR (real time polymerase chain reaction) were performed to assess the mRNA levels of the clock genes ARNTL, CLOCK1, PER1, and PER2. Subsequently, mRNA expression of important marker genes for periodontal and bone remodeling, OPG, RANKL, OCN, OPN, RUNX2, COL1A1, IL1β, KI67, and POSTN, were examined at time points of ARNTL amplitude expression. RESULTS: Gene expression of core clock genes varied over 48 h in accordance with the circadian rhythm. Functional markers, except KI67, showed significant differences at time points of maximum fluctuation especially of ARNTL. CONCLUSIONS: PDL fibroblasts express circadian clock genes. Our results suggest that genes associated with bone and periodontal remodeling are influenced by the circadian rhythm. Further research will have to refine the understanding of this influence for orthodontic treatment.
Entities:
Keywords:
ARNTL transcription factors; Chronobiology; Circadian rhythm signaling peptides and proteins; Orthodontics; Tooth movement
Authors: S Papagerakis; L Zheng; S Schnell; M A Sartor; E Somers; W Marder; B McAlpin; D Kim; J McHugh; P Papagerakis Journal: J Dent Res Date: 2013-09-24 Impact factor: 6.116
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