Tau hyperphosphorylation is the main pathological hallmark of Alzheimer’s disease (AD). Recent studies have already suggested that periodontitis and certain periodontal pathogens may be risk factors for Alzheimer’s. This study deciphers an underlying mechanism, identifying the specific role of Treponema denticola (T. denticola), one of the main pathogens of periodontitis.
T. denticola implicated in the pathogenesis of Alzheimer’s disease
The study in vivo carried out on mice having received T. denticola orally for 24 weeks shows, after analysis of the DNA of T. denticola in the hippocampus by PCR that:
- T. denticola administered orally colonizes brain tissue;
- promotes hyperphosphorylation of tau protein in neurons,
- active la microglie,
- and increases IL-1β and TNF-α levels in mouse hippocampus.
In vitro, T. denticola directly increased expression levels of IL-1β and TNF-α. Additionally, levels of hyperphosphorylated tau protein are also increased.
This work thus reveals that T. denticola can invade the hippocampus
-here mice- and promote hyperphosphorylation of tau protein in the brain by activating neuroinflammation.
Could periodontitis promote the development of Alzheimer’s disease?