Proteome analysis of glandular parotid and submandibular‐sublingual saliva in comparison to whole human saliva by two‐dimensional gel electrophoresis

Abstract

The secretions of the salivary parotid and submandibular-sublingual (SMSL) glands constitute the main part of whole human saliva (WS) in which proline-rich proteins (PRPs) and mucins represent dominant groups. Although proteome analysis had been performed on WS, no identification of PRPs or mucins by 2-DE and MS was achieved in WS and no comprehensive analysis of both glandular secretions is available so far. The aim of this study was to compare the protein map of WS to parotid and SMSL secretions for the display of PRPs and mucins. WS and glandular secretions were subjected to 2-DE and spots were analyzed by MALDI-MS. New components identified in WS were cyclophilin-B and prolyl-4-hydroxylase. Also acidic and basic PRPs as well as the proline-rich glycoprotein (PRG) could now be mapped in WS. Acidic PRPs were found equally in parotid and SMSL secretions, whereas basic PRPs and PRG were found primarily in parotid secretion. Salivary mucin MUC7 was identified in SMSL secretion. Thus, the more abundant proteins of WS can be explained mainly by mixed contributions of parotid and SMSL secretions with only few components remaining that may be derived from local sources in the oral cavity.

Characterisation and expression of SPLUNC2, the human orthologue of rodent parotid secretory protein

“…This low level of sequence identity coupled with the (Geetha et al 2005). The protein has also been identified in whole saliva by a number of independent proteomic studies (Vitorino et al 2004;Ramachandran et al 2006;Gou et al 2006;Walz et al 2006) as well as in minor gland saliva (Siqueira et al 2008) and as a component of acquired pellicle (Siqueira et al 2007). Consistent with our proposal that PLUNCs may function in a host defence capacity we have shown that peptides derived from SPLUNC2 are able to inhibit LPS mediated cytokine release and also inhibit LBP/LPS interactions (Geetha et al 2005).…”

“…We have also shown that the protein is secreted into major gland saliva. Previously SPLUNC2 has not been identified in saliva by western analysis but has been identified in a number of proteomic studies of whole saliva, major gland saliva and, most recently, minor gland saliva (Vitorino et al 2004;Ramachandran et al 2006;Guo et al 2006;Walz et al 2006;Siqueira et al 2008). Our western analysis clearly shows that multiple protein isoforms of SPLUNC2 exist in saliva and that these are most likely due to differential glycosylation.…”

Human body fluid proteome analysis

“…Numerous studies have been performed to identify saliva proteins using 2-DE/MS [362][363][364][365][366][367][368][369][370]. A significant number of spots on a typical saliva 2-D gel actually correspond to amylases, cystatins, and Igs [369,370].…”

SiO₂-nanocomposite film coating of CAD/CAM composite resin blocks improves surface hardness and reduces susceptibility to bacterial adhesion

“…A study analyzing the specific ligands of salivary proteins suggested that some are involved in the initial bacterial adhesion on surfaces. For example, prolinerich proteins and salivary mucins were present in the acquired pellicle and provided adhesion sites for receptor proteins of oral bacteria 39) . In contrast, many studies have suggested that the adsorption of salivary proteins on surfaces smoothes out the differences in surface properties of different materials, depending on the thickness, composition, and conformation of proteins in the adsorbed layer 35,39) .…”