Both the unique and repeat regions of the Porphyromonas gingivalis hemagglutin A are involved in adhesion and invasion of host cells

Abstract

Porphyromonas gingivalis is one of the major etiologic agents of adult periodontitis and has been associated with cardiovascular diseases. It expresses multiple hemagglutinins that are significant virulence factors that play an important role in bacterial attachment and invasion of host cells. The objective of this study was to determine the impact of P. gingivalis hemagglutinin A (HagA) on the attachment to and invasion of human coronary artery endothelial cells (HCAEC) and gingival epithelial cells (GEC). Bacterial strains expressing the HagA protein (or subunits), including Escherichia coli carrying plasmid pEKS5, E. coli carrying plasmid ST2, and Salmonella enterica serovar Typhimurium with plasmid pNM1.1 were used in this study. The strains were tested for their ability to attach to and invade HCAEC and GEC using antibiotic protection assays. In addition, the unique 5′ N-terminal non-repeated segment of HagA was purified in recombinant form and a monoclonal antibody was created against the polypeptide. The monoclonal antibody against the unique portion of HagA was tested for inhibitory activity in these assays. The attachment of both E. coli strains expressing HagA fragment to host cells was significantly increased compared to their respective controls. However they did not invade GEC or HCAEC. Interestingly, HagA expression in the Salmonella strain increased both adherence to and invasion of HCAEC, which may be due to the presence of the entire hagA ORF. A monoclonal antibody against the unique 5′ N-terminal portion of HagA reduced invasion. Further experiments are needed to determine the role of the unique and the repeat segments of P. gingivalis HagA.

<b><i>Porphyromonas gingivalis</i></b> Accelerates Neointimal Formation after Arterial Injury

“…Our histopathological analysis revealed that the intima/media thickness ratio in the P. gingivalis infected group was significantly increased in comparison to the non-infected group. There are many virulence factors of P. gingivalis such as lipopolysaccharides, fimbriae [33], gingipains, proteases [34] and hemagglutinin [35]. Previous studies indicated that P. gingivalis lipopolysaccharides trigger inflammatory pathways through the production of cytokines [36] and chemokines [37].…”

Biogenesis and Function of Porphyromonas Gingivalis Outer Membrane Vesicles

“…Several well-known membrane proteins involved in P. gingivalis attachment to, and invasion of, host cells have been identified within vesicles, including FimA, hemagglutinin A and heat-stress protein (HtrA) [50 –53]. Not surprisingly, therefore, vesicles derived from P. gingivalis have been found to invade human primary oral epithelial cells, gingival fibroblasts and human umbilical vein endothelial cells [20,54–56].…”

Toll-like receptor 4 signaling has a critical role in Porphyromonas gingivalis-accelerated neointimal formation after arterial injury in mice

“…26 There are many virulence factors of P. gingivalis, such as LPS, fimbriae, gingipains, proteases and hemagglutinin. [27][28][29] Previous studies indicated that P. gingivalis LPS triggered inflammatory pathways through the production of chemokines via the TLR4 pathway in human aortic endothelial cells 30 and human gingival fibroblasts. 31 MCP-1 is a principal factor in initiation and progression of neointimal formation.…”