Core matrisome protein signature during periodontal ligament maturation from pre-occlusal eruption to occlusal function

ABSTRACT: The pre-occlusal eruption brings the rat molars into functional occlusion, which implicates tensional strains during mastication. We hypothesized that upon establishment of occlusion, the periodontal ligament undergoes cell and extracellular matrix maturation to adopt to this mechanical function. We thus aimed to characterize the protein content and changes in expression levels of tensionally relevant extracellular matrix components in the periodontal ligament between the eruption and newly established occlusion in rat molars. Twelve Wistar male rats were divided into 3 groups based on eruption and occlusal stages: covering the pre-occlusal stages at time of eruption, the first day of occlusion and 1 week after occlusion. We employed laser capture microdissection to obtain samples of the periodontal ligament at three regions, cervical, apical and subapical. The proteome was screened with Tandem Mass Tag 10-plexTM mass spectrometry and the expression of key proteins were confirmed by immunofluorescence. Differential expression of matrisome proteins was seen in the cervical and the apical region. Downregulation of pro-metabolic proteins, such as apolipoproteins implicated in lipid transport was observed. Alpha-fetoprotein, a stem cell marker, was also downregulated indicating cell differentiation and PDL maturation. Upregulated proteins were components of the extracellular matrix, involving several proteoglycans and glycoproteins and the matrisome was thus further analyzed. Periostin appeared around collagen α-1 (III) fibers and its expression was particularly strong on Sharpey’s fibers. This co-localization coincided with organization of collagen fibers in direction of the occlusal forces. Establishment of occlusion coincides with cellular differentiation and the maturation of the extracellular matrix of the periodontal ligament, as seen by downregulation of the stem cell marker Alpha-fetoprotein and apolipoproteins, and the progressive accumulation of collagen type III fibers, proteoglycans, glycoproteins. The increase in collagen fiber associates periostin may reflect a physiological response to enforce cell-ECM contacts during PDL maturation.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Periodontal Ligament

SUBMITTER: Balazs Denes  

LAB HEAD: Balazs Jozsef Denes

PROVIDER: PXD013379 | Pride | 2019-10-10

REPOSITORIES: Pride