Proteomic analyses of human gingival and periodontal ligament fibroblasts

Although human gingival fibroblasts (hGFs) and human periodontal ligament fibroblasts (hPDLFs) exhibit numerous phenotypic similarities, it has been suggested that the secretory and behavioral differences, which exist between these cell types, are a result of the membrane protein composition of these cells.

Four matched pairs of hGFs and hPDLFs were cultured. Before confluence, membrane-bound and -associated proteins from cells of the fourth passage were extracted. The processed protein samples were evaluated using capillary-liquid chromatography-nanospray tandem mass spectrometry. Global protein identification was performed on an orbitrap mass spectrometer equipped with a microspray source operated in positive ion mode. Proteome software was used to validate protein identifications derived from tandem mass spectrometry sequencing results.

Four hundred fifty proteins were common to both hGFs and hPDLFs. Of the proteins identified, 214 were known membrane-bound or -associated proteins, and 165 proteins were known nuclear-associated proteins. Twenty-seven proteins, identified from the 450 proteins, common to both hGFs and hPDLFs, were detected in statistically significant greater quantities in either hGFs or hPDLFs. More specifically, 13 proteins were detected in significantly greater quantities in hGFs, whereas 14 proteins were detected in significantly greater quantities in hPDLFs.

Distinct differences in the cellular protein catalog may reflect the dynamic role and high energy requirements of hGFs in extracellular matrix remodeling and response to inflammatory challenge as well as the role of hPDLFs in monitoring mechanical stress and maintaining tissue homeostasis during regeneration and remineralization.