Potassium is a key signal in host-microbiome dysbiosis in periodontitis

Abstract

Dysbiosis, or the imbalance in the structural and/or functional properties of the microbiome, is at the origin of important infectious inflammatory diseases such as inflammatory bowel disease (IBD) and periodontal disease. Periodontitis is a polymicrobial inflammatory disease that affects a large proportion of the world's population and has been associated with a wide variety of systemic health conditions, such as diabetes, cardiovascular and respiratory diseases. Dysbiosis has been identified as a key element in the development of the disease. However, the precise mechanisms and environmental signals that lead to the initiation of dysbiosis in the human microbiome are largely unknown. In a series of previous in vivo studies using metatranscriptomic analysis of periodontitis and its progression we identified several functional signatures that were highly associated with the disease. Among them, potassium ion transport appeared to be key in the process of pathogenesis. To confirm its importance we performed a series of in vitro experiments, in which we demonstrated that potassium levels a increased the virulence of the oral community as a whole and at the same time altering the immune response of gingival epithelium, increasing the production of TNF-α and reducing the expression of IL-6 and the antimicrobial peptide human β-defensin 3 (hBD-3). These results indicate that levels of potassium in the periodontal pocket could be an important element in of dysbiosis in the oral microbiome. They are a starting point for the identification of key environmental signals that modify the behavior of the oral microbiome from a symbiotic community to a dysbiotic one.

The effect of the stress hormone cortisol on the metatranscriptome of the oral microbiome

“…Fig 2). We observed similar results in our two previous 123 studies on periodontitis progression 23 and the effect of ion potassium in functional dysbiosis of the 124 oral microbiome 24 . As a whole, these results seem to indicate that the presence of cortisol leads to a 125 community-wide response very similar to the one observed in vivo during periodontitis.…”

“…We included also results from 2 previous studies one on periodontal disease progression 23 and another 222 where we showed that potassium was a crucial signal in dysbiosis 24 To assess the effect that cortisol has on the oral microbiome we performed metatranscriptome 249 analysis of a biological triplicate of subgingival dental plaque from a periodontally healthy subject. 250…”

Guidance of zoospores by potassium gradient sensing mediates aggregation

“…The extent to which K + release from the microbiota present in the same habitat as the zoospores can mediate zoospore aggregation remains to be evaluated. Potassium seems to play a key role in the displacement of bacteria, the physical composition of microbiota [25] and pathogenic processes [26]. The electrical signalling mediated by potassium The red window indicates the area of the chamber taken into account in the analysis of zoospore tracking and measurement of the spatio-temporal concentration of potassium.…”

Guidance of zoospores by potassium gradient sensing mediates aggregation

“…To what extent K + release by microbiota sharing the zoospore habitat could mediate their aggregation remains to be evaluated. Potassium appears to be key in the displacement of bacteria, in the physical composition of microbiota [24] and in the process of pathogenesis [25]. Electrical signaling mediated by potassium ion channels regulates cell-cell dialogs within a bacterial biofilm with potassium driving attraction of distant cells of different species [24].…”