Differential transcription of virulence genes in Aggregatibacter actinomycetemcomitans serotypes

Abstract

Background Aggregatibacter actinomycetemcomitans serotypes are clearly associated with periodontitis or health, which suggests distinct strategies for survival within the host.ObjectiveWe investigated the transcription profile of virulence-associated genes in A. actinomycetemcomitans serotype b (JP2 and SUNY 465) strains associated with disease and serotype a (ATCC 29523) strain associated with health.DesignBacteria were co-cultured with immortalized gingival epithelial cells (OBA-9). The adhesion efficiency after 2 hours and the relative transcription of 13 genes were evaluated after 2 and 24 hours of interaction.ResultsAll strains were able to adhere to OBA-9, and this contact induced transcription of pgA for polysaccharide biosynthesis in all tested strains. Genes encoding virulence factors as Omp29, Omp100, leukotoxin, and CagE (apoptotic protein) were more transcribed by serotype b strains than by serotype a. ltxA and omp29, encoding the leukotoxin and the highly antigenic Omp29, were induced in serotype b by interaction with epithelial cells. Factors related to colonization (aae, flp, apaH, and pgA) and cdtB were upregulated in serotype a strain after prolonged interaction with OBA-9.ConclusionGenes relevant for surface colonization and interaction with the immune system are regulated differently among the strains, which may help explaining their differences in association with disease.

Effect of periodontal treatment on Aggregatibacter actinomycetemcomitans colonization and serum IgG levels against A. actinomycetemcomitans serotypes and Omp29 of aggressive periodontitis patients

“…The present prospective study indicated that clinical attachment gain in both forms of AgP was followed by a significant reduction in the serum IgG levels against Omp29, although the colonization levels of A. actinomycetemcomitans remained constant throughout the experimental period. The successful treatment resulted also in decreased levels of serum IgG to serotype b and reduction of the proportion of the JP2 clone in periodontal pockets, which is also in line with our previous data substantiating an increased expression of Omp29 by serotype b strains (Umeda et al, ).…”

“…We have already reported that AgP individuals can present differences in the IgG serum response against a variety of periodontopathogens (Saraiva et al, ). Nevertheless, doubts have remained as to how these differences may influence the periodontal treatment or could be related with our previous inferences on A. actinomycetemcomitans serotypes (Umeda et al, ) and expression of Omp29 under different environmental conditions (Longo, Nunes, Umeda, & Mayer, ).…”

“…Our previous work pointed out that genes encoding virulence factor of A. actinomycetemcomitans such as Omp29, Omp100, leukotoxin, and CagE were more transcribed by serotype b than by serotype a (Umeda et al, ). Omp29 belongs to the OmpA family, percentage family of outer membrane proteins of Gram‐negative pathogens with a multiplicity of functions, including adhesion and invasion of host cells, providing the ability to evade host defenses.…”

“…In this sense, clinical patterns associated with A. actinomycetemcomitans serotypes may be correlated to differences in their expression of virulence factors. For instance, the highly immunogenic outer membrane protein (Omp) 29 is associated with the entry of A. actinomycetemcomitans into gingival epithelial cells (Kajiya et al, ), and our previous study has pointed out differences in the transcription levels of Omp29 among A. actinomycetemcomitans serotypes (Umeda, Longo, Simionato, & Mayer, ). However, the impact of these findings on the clinical response of patients with AgP was still not evaluated.…”

Antibacterial Effectiveness of Selected Moroccan Essential Oils Against the Highly Virulent Jp2 Clone of Aggregatibacter Actinomycetemcomitans

“…Genome analysis revealed that this species comprises discrete clonal lineages represented by different serotypes (a, b, c, d, e, f) associated with periodontitis or health, which may help to explain their differences in virulence and in association with disease [4][5][6]. Serotype b strain with a 530-bp deletion in the promoter region of the leukotoxin operon is designated as JP2 clone.…”