OMP29 é uma das principais proteínas de membrana externa de Aggregatibacter actinomycetemcomitans (Aa) e está associada à invasão de célula epitelial gengival (CEG). Os objetivos deste estudo foram: analisar filogeneticamente omp29 e omp29 parálogo (omp29par), em cepas de Aa; determinar a interação de OMP29 com proteínas de matriz extracelular e o efeito da sua interação com CEG, pela avaliação da expressão gênica e produção de mediadores inflamatórios. Variações filogenéticas foram observadas para omp29 e omp29par, bem como para os seus promotores e estas relacionam-se com os sorotipos. A proteína recombinante OMP29his interagiu com fibronectina plasmática e celular (p<0,05), mas não com os domínios F30 e 45 ou com colágenos tipo I, III, IV e V, fibrinogênio, laminina e plasminogênio. A interação das mutantes de Aa deficientes em omp29 e/ou omp29par (obtidas pelo sistema LoxP/Cre) e OMP29his com CEG OBA-09 demonstrou que OMP29 regula positivamente il-18 e negativamente il-6r e il-8 (p<0,05). Os dados sugerem que OMP29 está envolvida na evasão do sistema imune. / OMP29 is one of the major outer membrane proteins of Aggregatibacter actinomycetemcomitans (Aa) and is associated with invasion into gingival epithelial cells (GEC). This study aimed to evaluate phylogenetically omp29 and omp29 paralogue (omp29par) in Aa strains; determine the interaction of OMP29 with extracellular matrix proteins and its effect on GEC by gene expression analysis and production of inflammatory mediators. Phylogenetic variations were observed for omp29 and omp29par as well as their promoters, and they were related to the serotypes. The recombinant protein OMP29his interacted with plasma and cellular fibronectin (p <0.05), but not to F30 and F45 domains, neither to collagens I, III, IV and V, fibrinogen, laminin and plasminogen. The interaction of Aa mutants defective in omp29 and/or omp29par (obtained by LoxP system/Cre) and OMP29his with CEG OBA-09 indicated that OMP29 regulates positively il-18 and negatively il-6r and il-8 (p <0.05). Data suggested that OMP29 is involved in bacterial evasion of the immune system.

OMP29 é uma das principais proteínas de membrana externa de Aggregatibacter actinomycetemcomitans (Aa) e está associada à invasão de célula epitelial gengival (CEG). Os objetivos deste estudo foram: analisar filogeneticamente omp29 e omp29 parálogo (omp29par), em cepas de Aa; determinar a interação de OMP29 com proteínas de matriz extracelular e o efeito da sua interação com CEG, pela avaliação da expressão gênica e produção de mediadores inflamatórios. Variações filogenéticas foram observadas para omp29 e omp29par, bem como para os seus promotores e estas relacionam-se com os sorotipos. A proteína recombinante OMP29his interagiu com fibronectina plasmática e celular (p<0,05), mas não com os domínios F30 e 45 ou com colágenos tipo I, III, IV e V, fibrinogênio, laminina e plasminogênio. A interação das mutantes de Aa deficientes em omp29 e/ou omp29par (obtidas pelo sistema LoxP/Cre) e OMP29his com CEG OBA-09 demonstrou que OMP29 regula positivamente il-18 e negativamente il-6r e il-8 (p<0,05). Os dados sugerem que OMP29 está envolvida na evasão do sistema imune. / OMP29 is one of the major outer membrane proteins of Aggregatibacter actinomycetemcomitans (Aa) and is associated with invasion into gingival epithelial cells (GEC). This study aimed to evaluate phylogenetically omp29 and omp29 paralogue (omp29par) in Aa strains; determine the interaction of OMP29 with extracellular matrix proteins and its effect on GEC by gene expression analysis and production of inflammatory mediators. Phylogenetic variations were observed for omp29 and omp29par as well as their promoters, and they were related to the serotypes. The recombinant protein OMP29his interacted with plasma and cellular fibronectin (p <0.05), but not to F30 and F45 domains, neither to collagens I, III, IV and V, fibrinogen, laminin and plasminogen. The interaction of Aa mutants defective in omp29 and/or omp29par (obtained by LoxP system/Cre) and OMP29his with CEG OBA-09 indicated that OMP29 regulates positively il-18 and negatively il-6r and il-8 (p <0.05). Data suggested that OMP29 is involved in bacterial evasion of the immune system.

The Gram-negative bacterium Aggregatibacter actinomycetemcomitans is primarily associatedwith aggressive forms of periodontal disease. Additionally, it has occasionally been found to causemetastatic infections in non-oral sites. This requires the ability to evade the bactericidal activity ofthe complement system of the humoral immune system. Outer membrane proteins, namely,Omp100 and OmpA have been connected to normal human serum resistance for several bacteriaspecies. The objective of this study was to investigate if serum-resistant ompA mutants can beobtained, and to detect changes in OMP expression. We used A. actinomycetemcomitansserotype a strain D7SS and D7SS ompA knockouts. The strains were incubated in 50 % NHS.This resulted in a substantial decrease of survival among D7SS ompA knockouts. D7SS ompAknockouts were exposed to 50 % NHS once more to confirm stable serum resistance. 13 out of14 tested clones showed growth, indicating that serum resistant ompA mutants could begenerated. SDS-PAGE gel of extracted outer membrane vesicles revealed an additional proteinband of approximately 34 kDa in at least 4 of 5 tested serum resistant ompA mutants. This proteinband has been analyzed in the laboratory, and according to LC-MS/MS it contains an OmpAhomologue, which has been named OmpA2. We conclude that OmpA2 expression might be amajor mechanism for serum survival in A. actinomycetemcomitans serotype a strain D7SS ompAknockouts.