Label-Free Quantitative Proteomics Reveals Differentially Regulated Proteins in Experimental Gingivitis

Abstract

We investigated the sequential protein expression in gingival crevicular fluid samples during the induction (I) and resolution (R) of experimental gingivitis. Periodontally and systemically healthy volunteers (n = 20) participated in a three-week experimental gingivitis protocol, followed by debridement and two weeks of regular plaque control. Gingival crevicular fluid (GCF) samples were collected at baseline, Day 7, 14, and 21 (induction; I-phase), and at Day 21, 25, 30, and 35 (resolution; R-phase). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for label-free quantitative proteomics was applied. A total of 287 proteins were identified including 254 human, 14 bacterial, 12 fungal, and 7 yeast proteins. Ontology analysis revealed proteins primarily involved in cytoskeletal rearrangements, immune response, antimicrobial function, protein degradation, and DNA binding. There was considerable variation in the number of proteins identified, both among subjects and within subjects across time points. After pooling of samples between subjects at each time point, the levels of 59 proteins in the I-phase and 73 proteins in the R-phase were quantified longitudinally. Our data demonstrate that LC-MS/MS label-free quantitative proteomics is valuable in the assessment of the protein content of the GCF and can facilitate a better understanding of the molecular mechanisms involved in the induction and resolution of plaque-induced gingival inflammation in humans.

Quantitative Proteomic Analysis of Gingival Crevicular Fluid in Different Periodontal Conditions

“…Perhaps, by increasing the number of subjects sampled, it is possible that the range of proteins detected increases. Other studies that evaluate the GCF from healthy or diseased subjects have reported a lower number of detected proteins [7,10,15–17], while others have identified a higher amount [9,18]. In the study of Baliban et al [9], 432 human proteins were found.…”

“…Furthermore, myosin-9 can stimulate leukocyte migration and monocyte differentiation [10]. Myosin-9 and fibrinogen alpha chain were detected only in the resolution phase of experimental gingivitis, while histone H1.5 was detected in relative high frequency in both phases (induction and resolution) [15]. In another experimental gingivitis study, the authors also found myosin-9, fibrinogen alpha and beta chains, histone H1.5 and cathelicidin antimicrobial peptide [16].…”

“…This multi-biomarker approach has progressed by recent advances in clinical proteomics [12–14]. Many studies have been performed in GCF analyzing its proteome profile through mass spectrometry (MS) technology [7,9,10,15–19]. Those studies differed in relation to the clinical condition, including studies of experimental gingivitis [15,16], aggressive periodontitis subjects [7], CP subjects [9,18,19], and healthy subjects [10].…”

Gingival Crevicular Fluid as a Novel Potential Source of Biomarkers Distinguishes Pubertal from Post-Pubertal Subjects

“…GCF is part of saliva that is comprised of complicated protein content and remains more stable regardless of tooth brushing and eating [9], with a characteristic of site-specificity. The total amounts of proteins and peptides that have been identified in GCF in periodontal healthy subjects are reported to be in a range from 88 [29] to 327 [30] that depends on the different sample sizes and methods employed in different studies. Many studies have applied gel-based or gel-free mass spectrometric analysis of GCF proteomic profiling for the detection of novel biomarkers of periodontitis and have successfully discovered several protein biomarkers that have never been investigated before [20,21,31], and some have confirmed the significance of biomarkers that had been proposed in previous studies via conventional research methods [30].…”

Serum proteomic-based analysis by iTRAQ of damp-heat impeding syndrome of rheumatoid arthritis

“…There are very little report about this protein. However, it is thought to play a role in the immune response [34].…”