Lira dos Santos, Elis J.
de Almeida, Amanda B.
Chavez, Michael B.
Salmon, Cristiane R.
Mofatto, Luciana S.
Camara-Souza, Mariana Barbosa
Tan, Michelle H.
Kolli, Tamara N.
Mohamed, Fatma F.
Chu, Emily Y.
Novaes, Pedro Duarte
Santos, Eduardo C. A.
Kantovitz, Kamila R.
Foster, Brian L.
Nociti Jr, Francisco H.
Total Authors: 15
 Univ Estadual Campinas, Dept Prosthodont & Periodont, Div Periodont, Piracicaba Dent Sch, Sao Paulo - Brazil
 Ohio State Univ, Div Biosci, Coll Dent, Columbus, OH 43210 - USA
 N Sra do Patrocinio Univ Ctr, Fac Dent, Itu, SP - Brazil
 Univ Estadual Campinas, Dept Prosthodont & Periodont, Div Prosthodont, Piracicaba Dent Sch, Sao Paulo - Brazil
 NIAMSD, NIH, Bethesda, MD 20892 - USA
 Univ Estadual Campinas, Piracicaba Dent Sch, Dept Morphol, Sao Paulo - Brazil
 Univ Estadual Campinas, Piracicaba Dent Sch, Dept Pediat Dent, Div Orthodont, Sao Paulo - Brazil
 Sao Leopoldo Mandic Res Ctr, Dept Dent Mat, Campinas, SP - Brazil
Total Affiliations: 9
Web of Science Citations:
Cementum is a mineralized tissue that covers tooth roots and functions in the periodontal attachment complex. Cementocytes, resident cells of cellular cementum, share many characteristics with osteocytes, are mechanoresponsive cells that direct bone remodeling based on changes in loading. We hypothesized that cementocytes play a key role during orthodontic tooth movement (OTM). To test this hypothesis, we used 8-week-old male Wistar rats in a model of OTM for 2, 7, or 14 days (0.5 N), whereas unloaded contralateral teeth served as controls. Tissue and cell responses were analyzed by high-resolution micro-computed tomography, histology, tartrate-resistant acid phosphatase staining for odontoclasts/osteoclasts, and transmission electron microscopy. In addition, laser capture microdissection was used to collect cellular cementum, and extracted proteins were identified by liquid chromatography coupled to tandem mass spectrometry. The OTM model successfully moved first molars mesially more than 250 mu m by 14 days introducing apoptosis in a small number of cementocytes and areas of root resorption on mesial and distal aspects. Cementocytes showed increased nuclear size and proportion of euchromatin suggesting cellular activity. Proteomic analysis identified 168 proteins in cellular cementum with 21 proteins found only in OTM sites and 54 proteins only present in control samples. OTM-down-regulated several extracellular matrix proteins, including decorin, biglycan, asporin, and periostin, localized to cementum and PDL by immunostaining. Furthermore, type IV collagen (COL14A1) was the protein most downregulated (-45-fold) by OTM and immunolocalized to cells at the cementum-dentin junction. Eleven keratins were significantly increased by OTM, and a pan-keratin antibody indicated keratin localization primarily in epithelial remnants of Hertwig's epithelial root sheath. These experiments provide new insights into biological responses of cementocytes and cellular cementum to OTM. (AU)