Downregulation of protein and mRNA levels of vimentin in periodontitis – A potential biomarker candidate for periodontal severity?

Abstract Objective To identify a differentially expressed structural protein in moderate and severe periodontitis and to quantify its corresponding mRNA levels. The secondary objective is to find correlation, if any, between Porphyromonas gingivalis load and mRNA levels of the protein. Materials and methods Total protein was extracted from 30 human gingival tissues (10 each from healthy, moderate and severe periodontitis) and subjected to 2D-gel electrophoresis. Protein identification was done by LC-MS/MS. The mRNA levels of protein and load of Porphyromonas gingivalis were further quantified by qRT-PCR. Results 2D-gel Image Master 2D Platinum 7.0 analysis revealed a significant decrease (p ≤ 0.02) in the protein of MW 53.6 kDa in severe periodontitis compared to moderate periodontitis and healthy controls. LC-MS/MS analysis of the protein by MASCOT identified the protein as vimentin. Further, a three-fold decrease in mRNA expression of vimentin in periodontitis was obtained. A weak negative correlation was observed between Porphyromonas gingivalis load and mRNA levels of vimentin. Conclusion Differentially expressed protein in 2D gel was identified as structural protein Vimentin and it was significantly downregulated at gene and protein level in periodontitis. This suggests the participation of vimentin in the pathogenesis of periodontitis.