Session: Session 5

Proteomic analyses of gum tissues and CD45-enriched cells from periodontitis patients

Hugo EICHHORN¹, Nathan COUFFIN¹, Laura TALAMINI⁴, Hayryie OZCELIK^2,3, Olivier HUCK^2,3, Sylviane MULLER⁴, Laurence EHRET-SABATIER¹

¹Laboratoire de spectrométrie de masse bio organique, Strasbourg, France
²Faculté de chirurgie dentaire, University of Strasbourg, Strasbourg, France
³INSERM UMR 1260, INSERM-University of Strasbourg, Strasbourg, France
⁴Neuroimmunologie et thérapie peptidique, UMR7242, CNRS-University of Strasbourg, Strasbourg, France

Introduction

Periodontitis is a gum infection that damages the soft tissue and bone that supports the tooth. It occurs in about 20–50% of the global population, with 11% of severe forms that may require surgical interventions [1]. The invasive nature, elevated costs and associated side effects of the treatments reinforce the need to develop better alternatives for the patients. In this context, a previous study was conducted in a mouse periodontitis model to explore the effects of P140, a peptide that corrects autophagy dysfunctions in several autoimmune and inflammatory diseases [2]. This study demonstrated the ability of P140 to decreases the inflammatory effects and to contribute to bone preservation [3]. Our objective is to decipher the P140’s mechanisms of action, using label-free proteomics in human and in a mouse periodontitis model.

Methods

Proteins were extracted, from gum tissues or CD45-enriched cells, in a Tris-HCl 62.5 mM buffer pH 6.8, 2% SDS, then they were digested using an SP3 protocol. LC-MS/MS analyses were conducted on a timsTOF Pro 2 mass spectrometer (Bruker) or on a Q Exactive HF-X (Thermo Fisher). In case of timsTOF Pro 2, acquisitions were carried out in DDA or DIA modes.

Results

In human gingival tissues, we identified > 6500 proteins thanks to diaPASEF analysis. However, no differential proteins could be discovered with confidence between healthy and diseased tissues, neither in DDA nor in DIA. This may be due to the high variability observed between individuals in the same group. Thus, we investigated CD45-enriched cells to reduce the sample complexity. We examined the minimal amount of starting cells, and we identified around 1000 proteins on the Q Exactive HF-X platform in DDA mode. The collection of CD45-enriched cells for the differential analysis is under progress. In parallel, we set up the proteomic workflow in a mouse periodontitis model, to perform differential analyses between healthy, diseased and P140-treated mice.