title: Development of novel in vitro models to investigate the role of pathogens in the aetiology of feline chronic gingivostomatitis and to test therapeutic interventions
Creators: name: Bonner, Nicole
Publisher: name: University of Glasgow
Year: 2020
Subjects: subject: FCGS, feline, oral.

description: Feline chronic gingivostomatitis (FCGS) is a severe inflammatory disease of the oral cavity that causes extreme pain and distress in affected cats. Treatment options for FCGS are limited, and often unsatisfactory, and there is a poor understanding regarding its aetiology. Recent literature indicates that several putative bacterial pathogens, including T. forsythia and P. circumdentaria, could be involved in the development and progression of disease by stimulating an excessive host immune response. Understanding how the host responds to bacteria associated with FCGS is of importance to help identify novel targets for therapeutic strategies which are highly sought after. The aim of this study was to investigate the impact of putative pathogenic bacteria on the host inflammatory response and test the anti-microbial potential of several compounds on an FCGS-associated multispecies biofilm. A panel of bacteria found to be prevalent in FCGS were selected as a basis for in vitro research into the immune response from host cells following exposure to these bacteria. The QUANTI-BlueTM assay was used to measure toll-like receptor (TLR) activation in human THP1-XBlueTM pro-monocytes. IL-8 gene expression and protein release was measured from both human and feline cell lines by qPCR and ELISA, respectively. Moreover, the antimicrobial potential of novel agents including carbohydrate-derived fulvic acid (CHD-FA), xylitol, berberine, and ubiquinol were assessed against a multi-species biofilm consisting of bacteria prevalent in FCGS. The effect of these compounds on biofilm cell viability was determined using alamarBlue® and the impact on biofilm biomass was measured using the crystal violet assay. The results from this study have generally shown that putative pathogens such as T. forsythia, P. multocida subsp. multocida, and P. multocida subsp. septica at a multiplicity of infection (MOI) of 200 produced the greatest increase in secreted embryonic alkaline phosphatase (SEAP) expression/TLR activation (p&lt;0.001) in human cells and significant IL-8 release in human and feline cells. Commensal B. zoohelcum displayed an unexpected increase in IL-8 gene expression (p&lt;0.01) and protein release (p&lt;0.001) at an MOI of 200 in the squamous carcinoma cell feline cell line (SCCF1). Furthermore, the novel agent CHD-FA showed to significantly decrease biofilm cell viability (p&lt;0.01) and biomass (p&lt;0.05) at 0.8% compared to the untreated control, while berberine disrupted only biofilm biomass at 100 μg/mL (p&lt;0.05). Xylitol and ubiquinol had no significant impact on biofilm metabolic activity or biomass. To conclude, this research has highlighted the inflammatory potential of bacteria associated to FCGS and how this may reflect the chronic inflammation presented by the host during disease. The development of a multi-species biofilm provided a platform to test novel compounds, highlighting its potential to be used as a tool in discovering appropriate therapeutic targets for FCGS and other biofilm infections. Such findings are valuable to enhance our understanding of the complex aetiology of FCGS and may help identify novel treatment interventions.