Gum Disease Bacteria Linked to Neuroinflammation in Preclinical Alzheimer's Study

Posted: May 20, 2026

Gum Disease Bacteria Linked to Neuroinflammation in Preclinical Alzheimer's Study

Edited by Dentaltown staff

A preclinical study published May 19 in BMC Oral Health identified a molecular pathway by which outer membrane vesicles released by the periodontal pathogen Porphyromonas gingivalis may contribute to neuroinflammation and neuronal injury, deepening the mechanistic case for a link between periodontitis and Alzheimer’s disease.

Researchers at Fudan University in Shanghai gave 8-week-old male C57BL/6 mice bilateral gingival injections of P. gingivalis-derived outer membrane vesicles three times weekly for eight weeks. Treated mice showed significant cognitive impairment on the Morris water maze (p<0.001), along with accumulation of amyloid beta plaques and hyperphosphorylated tau in brain tissue.

RNA sequencing of brain tissue identified differentially expressed genes concentrated in mitochondrial pathways, with transglutaminase 2 emerging as a key target. In parallel cell-culture experiments using HT22 hippocampal cells, treatment with the vesicles increased pro-inflammatory cytokines including IL-1β and IL-17, decreased anti-inflammatory IL-10, and upregulated transglutaminase 2.

The investigators reported that the vesicles promoted formation of mitochondria-associated endoplasmic reticulum membranes in neurons, with disrupted mitochondrial calcium levels and membrane potential. The cells also showed altered expression of ferroptosis markers, including increased ACSL4 and decreased GPX4 and xCT. Knocking down transglutaminase 2 with siRNA reversed the inflammation, ferroptosis, mitochondrial dysfunction, and membrane formation, identifying the enzyme as a potential therapeutic target.

The corresponding authors were Kairun Zhang of the Department of Orthodontics and Shengcai Qi of the Department of Prosthodontics, both at Shanghai Stomatological Hospital and Fudan University. Funding came from the Shanghai Stomatological Hospital. The authors reported no competing interests.

The findings are preclinical and limited to mouse and cell-culture models. The authors did not test interventions in humans or evaluate whether the mechanism would change clinical management of periodontitis. The paper is currently available as an early-access unedited manuscript pending final copyediting.

Sources:
BMC Oral Health, “Porphyromonas gingivalis outer membrane vesicles drive neuroinflammation via TGM2-mediated mitochondria-associated endoplasmic reticulum membranes,” Zhang P, et al., May 19, 2026: link.springer.com/article/10.1186/s12903-026-08458-5
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