Proteomic analysis of human dental cementum and alveolar bone

Abstract

Dental cementum (DC) is a bone-like tissue covering the tooth root and responsible for attaching the tooth to the alveolar bone (AB) via the periodontal ligament (PDL). Studies have unsuccessfully tried to identify factors specific to DC versus AB, in an effort to better understand DC development and regeneration. The present study aimed to use matched human DC and AB samples (n=7) to generate their proteomes for comparative analysis. Bone samples were harvested from tooth extraction sites, whereas DC samples were obtained from the apical root portion of extracted third molars. Samples were denatured, followed by protein extraction reduction, alkylation and digestion for analysis by nanoAcquity HPLC system and LTQ-FT Ultra. Data analysis demonstrated that a total of 318 proteins were identified in AB and DC. In addition to shared proteins between these tissues, 105 and 83 proteins exclusive to AB or DC were identified, respectively. This is the first report analyzing the proteomic composition of human DC matrix and identifying putative unique and enriched proteins in comparison to alveolar bone. These findings may provide novel insights into developmental differences between DC and AB, and identify candidate biomarkers that may lead to more efficient and predictable therapies for periodontal regeneration.

Extracellular matrix networks in bone remodeling

“…The mineralized portion of the ECM is composed largely of calcium-phosphate in the form of hydroxyapatite plus an extensive type I collagen-rich organic ECM. In addition to collagen, proteomic analysis of decalcified bone suggests that well-over 100 ECM proteins are present in bone (Jiang et al, 2007;Salmon et al, 2013). Similarly, analysis of osteoblasts show that ECM proteins represent 30% of the 315 proteins identified via secretome analysis .…”

“…1 illustrates the simplified cellular anatomy of bone and illustrates that different tissue compartments are connected functionally and spatially. In addition to mineralized bone ECM other unique tissue types exist in association with bone, including, (Jiang et al, 2007) marrow; (Salmon et al, 2013) endosteum; periosteum; and (Bos et al, 2004) the osteocyte perilucanar matrix. Marrow, endosteum, periosteum, and perilucanar matrix are all non-mineralized and contain ECM networks that can regulate the processes of osteoclast development and function, osteoblast progenitor proliferation and differentiation, and osteocyte function.…”

Cellular and Molecular Pathways Leading to External Root Resorption

“…At the proteomic level (Salmon et al 2013), studies of human dental cementum compared with alveolar bone revealed that up to 318 proteins in common can be found in both tissues. Nevertheless, 83 proteins were found exclusively in the cementum, implicated in different cellular pathways.…”

“…This SOD is a member of the SOD family that acts as a critical cellular protection against O2− and peroxynitrite. Interestingly, SOD3 was immunolocalized in cervical root cementoblasts and around apical third cementocytes (Salmon et al 2013). These regions are well known as areas sensitive to root resorption; hence, regarding SOD3 localization and its function, this protein could play a key role as a "defense" from oxidative stress during cementum maintenance.…”

Vitamin D: calcium and bone homeostasis during evolution

“…2,3 It may also have many extraskeletal effects by regulating a large number of genes. The concentration of ionized calcium in extracellular and intracellular compartments is very tightly regulated in vertebrates as well as in invertebrates, whereas an endoskeleton structure is a typical hallmark of terrestrial vertebrates (tetrapods), preceded earlier in evolution in fish jaw bones and the skeleton of bony fish.…”