Salivary peptidome in type 1 diabetes mellitus

Abstract

Diabetic patients show a high susceptibility to oral diseases of inflammatory, catabolic and chronic nature with potential impact on saliva composition. In this study, our purpose was to characterize type 1 diabetes-induced alterations in the salivary peptidome aiming to find prospective biomarkers for type 1 diabetes oral health evaluation. Peptidomic analysis of saliva from controls (n = 5) and type 1 diabetic patients (n = 5) were performed by liquid chromatography followed by mass spectrometry. The proteolytic activity and metalloproteinases expression was accessed by zymography and slot blot analysis, respectively. Data evidenced a significant increase in the percentage of peptides in diabetic patients paralleled by a higher proteolytic activity, compared with healthy individuals. The nonsalivary gland protein fragments identified in saliva were mainly derived from collagen and extracellular matrix proteins, namely collagen type I. The cleavage site frequency analysis showed significant differences between healthy and type 1 diabetic individuals, highlighting the activity of proteases such as matrix metalloproteinase-9 and cathepsin D. Our results highlight salivary collagen fragments as potential biomarkers to follow up diabetes-related oral damage.

endoProteoFASP: A novel FASP approach to profile salivary peptidome and disclose salivary proteases

“…After 18 h and 115 h of incubation, the majority of the eluted peptides belonged almost exclusively to the different PRP isoforms, suggesting that these proteins display the highest susceptibility to ex vivo proteolysis. Cleavage site analysis showed that the peptide bond between GlnGly residues was the preferential site for proteolysis, which is in agreement with previous findings [29][30][31][32]. Interestingly, the formation of the new PRPs peptides is associated with a time-dependent profile of proteases, a variation never reported so far, to the best of our knowledge.…”

“…Despite inter-individual variability, PRPs, P-B peptide, histatin 1 and 3, mucin 7, polymeric immunoglobulin receptor and statherin represented the most susceptible salivary proteins to proteolysis in vivo, as proven by the number of peptides identified to these proteins at T0 (Table 1) which is corroborated by the LC-MS/MSbased characterization of whole salivary peptidome [29][30][31]. Protein fragments at T0 were attributed to the activity of CTSL1 and MEP1A.…”

Clinical and diagnostic utility of saliva as a non-invasive diagnostic fluid: a systematic review

“…These proteins may be involved in the development of DM associated complications or are markers for such complications ( 56 ). Another study on Type 1 DM induced salivary peptidome alterations revealed high activity of proteases such as matrix metalloproteinase-9 (MMP-9) and cathepsin D and presented salivary collagen fragments as potential biomarkers to follow up DM-related oral damage ( 57 ). Salivary proteomic profiles in patients with periodontitis and healthy subjects, showed distinct change in proteins in presence of inflammation, which can lead to the improvement of periodontal disease diagnosis ( 58 ).…”

Protein Electrophoresis in Saliva Study

“…Proteomic techniques such as two-dimensional electrophoresis (2-DE), 2D-liquid chromatography/mass spectrometry (2D-LC/MS), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS), and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF/MS), have been used in saliva studies. Based on those techniques, potential salivary biomarkers for diseases such as Sjögren syndrome [20], diabetes mellitus [21] and some different cancers [22] have been suggested. 2-DE has been one technique of choice for the global analysis and initial profiling of salivary proteins, being used as a first step for protein separation, followed by MS or tandem MS (MS/MS) [23].…”