Porphyromonas gingivalis HmuY stimulates expression of Bcl-2 and Fas by human CD3+ T cells

Paulo C Carvalho-Filho,Soraya C Trindade,Lilia Moura-Costa,Bianca F P Pereira,Heidiane A Santos,Milton G Oliveira-Neto,Roberto Meyer,Geraldo P Sampaio,Márcia T Xavier,Teresa Olczak

doi:10.1186/1471-2180-13-206

Abstract

BackgroundApoptosis is a highly controlled process of cell death that can be induced by periodontopathogens. The present study aimed to investigate the expression of Fas and Bcl-2 proteins by CD3+ T cells in vitro under stimulation by total Porphyromonas gingivalis antigens and purified recombinant P. gingivalis HmuY protein.ResultsCD3+ T cells derived from CP patients and stimulated with HmuY expressed higher levels of Bcl-2 compared to identical cells stimulated with P. gingivalis crude extract or cells derived from NP control subjects (p = 0.043).ConclusionThe authors hypothesize that P. gingivalis HmuY plays a role in the pathogenesis of chronic periodontitis, possibly by reducing or delaying apoptosis in T cells through a pathway involving the Bcl-2 protein.

Highlights

Apoptosis is a highly controlled process of cell death that can be induced by periodontopathogens
The cells from chronic periodontitis (CP) patients exhibited a tendency towards increased Bcl-2 expression under stimulation by HmuY when compared to those stimulated by P. gingivalis crude extract or to cells cultured in the absence of stimulus (Figure 1)
A tendency toward elevated levels of Fas expression were observed in CD3+ T cells derived from CP patients when compared to NP subjects (Figure 2)

Summary

Introduction

Apoptosis is a highly controlled process of cell death that can be induced by periodontopathogens. Bacteria acquire nutrients to survive and multiply at the site of infection. A previously characterized heme uptake system in P. gingivalis utilizes two proteins: HmuY, which scavenges heme from host hemoproteins, and HmuR [2,3,4], which transports the nutrient across bacterial cell membranes. These proteins are virulent factors, yet they can be antigenic and immunogenic as well, potentially affecting a host’s immune system with respect to stability and resistance

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Discussion

Conclusion