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Review
. 2022 Jul 26:13:945523.
doi: 10.3389/fneur.2022.945523. eCollection 2022.

Porphyromonas gingivalis: A key role in Parkinson's disease with cognitive impairment?

Dongcheng Li  1 , Tengzhu Ren  2 , Hao Li  1 , Geng Liao  1 , Xiong Zhang  1
Affiliations
Review

Porphyromonas gingivalis: A key role in Parkinson's disease with cognitive impairment?

Dongcheng Li et al. Front Neurol. .

Abstract

Cognitive impairment (CI) is a common complication of Parkinson's disease (PD). The major features of Parkinson's disease with cognitive impairment (PD-CI) include convergence of α-Synuclein (α-Syn) and Alzheimer's disease (AD)-like pathologies, neuroinflammation, and dysbiosis of gut microbiota. Porphyromonas gingivalis (P. gingivalis) is an important pathogen in periodontitis. Recent research has suggested a role of P. gingivalis and its virulence factor in the pathogenesis of PD and AD, in particular concerning neuroinflammation and deposition of α-Synuclein (α-Syn) and amyloid-β (Aβ). Furthermore, in animal models, oral P. gingivalis could cause neurodegeneration through regulating the gut-brain axis, suggesting an oral-gut-brain axis might exist. In this article, we discussed the pathological characteristics of PD-CI and the role of P. gingivalis in them.

Keywords: Parkinson's disease; Porphyromonas gingivalis; amyloid-β; cognitive impairment; gut microbiota; neuroinflammation; α-Synuclein.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
The potential pathways of P. gingivalis involvement in Parkinson's disease with cognitive impairment (PD-CI). (A) P. gingivalis enters the vasculature from the periodontal pocket, leading to bacteremia and systemic inflammation. (B) Gingipain and lipopolysaccharide (LPS) produced by P. gingivalis are present in the blood. (C) P. gingivalis infection induces the production of peripheral amyloid-β (Aβ) in inflammatory macrophages. (D) P. gingivalis impairs the function of the blood-brain barrier (BBB) by facilitating LPS, gingipain, and peripheral Aβ entry to the brain more easily, which causes neuroinflammation and Alzheimer's disease (AD)-type pathologies. (E) P. gingivalis is swallowed and enters the intestine. (F) P. gingivalis induces dysbiosis of the gut microbiota and intestinal inflammation, contributing to the accumulation of aberrant α-Synuclein (α-Syn) in the gut. (G) Aberrant α-Syn propagates from the gut to the brain via the vagus nerve. (H) Neuroinflammation, AD-type pathologies, and α-Syn promote each other effect in the brain, leading to a vicious cycle and resulting in PD-CI.
See this image and copyright information in PMC

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