RESUMEN
BACKGROUND: The development of chronic periodontitis was due to not only periodontal pathogens, but also the interaction between periodontal pathogens and host. The aim of this study is to investigate the alterations in gene expression in Porphyromonas gingivalis (P.gingivalis) W83 after inoculation in rat oral cavity. RESULTS: P.gingivalis W83 inoculation in rat oral cavity caused inflammatory responses in gingival tissues and destroyed host alveolar bone. Microarray analysis revealed that 42 genes were upregulated, and 22 genes were downregulated in the detected 1786 genes in the inoculated P.gingivalis W83. Real-time quantitative PCR detection confirmed the expression alterations in some selected genes. Products of these upregulated and downregulated genes are mainly related to transposon functions, cell transmembrane transportation, protein and nucleic acid metabolism, energy metabolism, cell division and bacterial pathogenicity. CONCLUSIONS: P.gingivalis W83 has a pathogenic effect on host oral cavity. Meanwhile, inflammatory oral environment alters P.gingivalis W83 gene expression profile. These changes in gene expression may limit the proliferation and weaken the pathogenicity of P.gingivalis W83, and favor themselves to adapt local environment for survival.
Asunto(s)
Proteínas Bacterianas/genética , Infecciones por Bacteroidaceae/microbiología , Periodontitis Crónica/microbiología , Boca/microbiología , Porphyromonas gingivalis/genética , Animales , Infecciones por Bacteroidaceae/genética , Periodontitis Crónica/genética , Perfilación de la Expresión Génica , Regulación Bacteriana de la Expresión Génica , Interacciones Huésped-Patógeno , Análisis de Secuencia por Matrices de Oligonucleótidos , Ratas , Organismos Libres de Patógenos EspecíficosRESUMEN
OBJECTIVE: Respiratory epithelial cells are the first natural barrier against bacteria and viruses; hence, the interactions among epithelial cells, bacteria, and viruses are associated with disease occurrence and development. The effect of co-infection by P. gingivalis and influenza A virus (IAV) on respiratory epithelial cells remains unknown. The aim of this study was to analyze in vitro cell viability and apoptosis rates in respiratory epithelial A549 cells infected with P. gingivalis or IAV alone, or a combination of both pathogens. DESIGN: A549 cells were first divided into a control group, a P. gingivalis group, an IAV group, and a P. gingivalisâ¯+â¯IAV group, to examine cell viability and apoptosis rates, the levels of microtubule associated protein 1 light chain 3â¯B (LC3-II), microtubule associated protein 1 light chain 3A (LC3-I), and sequestosome 1 (P62), and the formation of autophagosomes. The autophagy inhibitor, 3-methyladenine (3MA), was used to assess autophagy and apoptosis in A549 cells infected with P. gingivalis or IAV. RESULTS: An MTT assay revealed that cell viability was significantly lower in the IAV group than in the P. gingivalisâ¯+â¯IAV group (Pâ¯<â¯0.05). Flow cytometry indicated that the apoptosis rate was significantly higher in the IAV group than in the P. gingivalisâ¯+â¯IAV group (Pâ¯<â¯0.05). The fluorescence levels of GFP-LC3 increased significantly, the LC3-II/LC3-I ratio was significantly higher, and the P62 protein levels were statistically lower in the P. gingivalisâ¯+â¯IAV group compared with the IAV group (all Pâ¯<â¯0.05). Western blotting revealed that the LC3- II/LC3-I ratio was significantly lower, and caspase-3 levels were significantly higher in the 3MAâ¯+â¯P. gingivalisâ¯+â¯IAV group compared to the P. gingivalisâ¯+â¯IAV group (all Pâ¯<â¯0.05). CONCLUSION: In vitro studies showed that infection by P. gingivalis combined with IAV temporarily inhibited apoptosis in respiratory epithelial cells, and this may be related to the initiation of autophagy.