Oral microbiology: host-pathogen interactions

The interactions of oral bacterial with the tissues and infiltrating immune cells of the oral cavity are key to our understanding of key oral disease including periodontal disease.

Virulence factors of Tannerella forsythia and Porphyromonas gingivalis

Our current work focuses on surface molecules of P. gingivalis and how these influence interactions with epithelial cells. For example, we recently highlighted the role of surface loops of OmpA in this process and Ashley Gains continues to follow up this work while expanding it to other surface components.

OmpA including surface loops

Role of glycosidases at the host interface

While often forgotten, the surface of all cells is coated with glycans and the oral mucosal-bacterial interface as well as oral secretions (saliva, GCF) are also rich in glycans. Bacteria often possess glycosidases that remove sugars from host-glyoproteins (see below) and lectins that target these glycans for a range of reasons.

One impact of these glycosidases is their role in bacterial-host docking, entry into cells and also as a modulator of innate immune responses.

Our lab continues to examine all of these aspects and also investigate the role of novel inhibitors of these enzymes as a potential treatment adjunct for microbial diseases- including periodontitis.

Image: T. forsythia removal of alpha 2,3-linked sialic acid from the surface of oral epithelial cells is mediated by it’s NanH sialidase

Role of bacterial and human derived vesicles

In collaboration with Professor Dan Lambert, Jenna Jarvis is investigating the role of both bacterial outer membrane vesicles of P. gingivalis and human extracellular vesicles and their role in influencing bacterial and human cell responses.

We hypothesise that these membrane vesicles are key to two way communication at the host-pathogen interface, potentially modulating innate immunity and senescence phenotypes.

Human EV from Oral cells (credit Jenna Jarvis)
P. gingivalis + OMVs