Life science
Medical & healthcare, Pharmaceuticals

Elucidation of the enteric metabolic exacerbation of periodontal disease indiabetes and the mechanism of enhanced gluconeogenesis
Department of Periodontology, Graduate School of Dentistry
Professor Shinya Murakami			https://researchmap.jp/Shinya_Murakami?lang=en

Assistant Professor Yoichiro Kashiwagi

https://researchmap.jp/_yoichirok?lang=en

Several hypotheses have been proposed to explain the molecularmechanisms that connect oral health deterioration, exemplified by conditions such as dental caries and periodontal disease, with overall healthstatus. However, the precise nature of this causal relationship is not fully
understood. Under the working hypothesis that “dysbiosis of the oral
microbiota induces dysbiosis of the gut microbiota and exacerbates theoverall health,” our research group established an experimental mousemodel of periodontitis by oral administration of Porphyromonas gingivalis(Pg), a periodontal pathogen, to diabetic mice (db/db) for one month.Fig.1
Metaproteomic and metabolomic analyses were conducted on liver andfecal samples collected from the experimental mice. The results revealed
that alterations in the gut microbiota and metabolites due to the deterioration of the oral environment resulted in increased hepatic gluconeogenesis
via the portal vein, which worsened the pathophysiology of diabetes.

▍ Background & Results
Numerous reports have suggested a relationship between deterioration oforal health, represented by periodontal disease, and various systemic diseases. However, the precise molecular mechanisms linking oral environmental deterioration to overall health remain unclear. Several hypotheses havebeen proposed, including bacteremia resulting from bacterial infections
originating in the periodontal tissues or the chronic production of inflammatory cytokines, such as TNF-α, in inflamed periodontal tissues, leading
to systemic circulation. Multiple studies have indicated that deteriorationof the gut microbiota influences systemic diseases. Therefore, a working
hypothesis has been proposed that oral bacteria, when ingested with foodand saliva, can cause dysbiosis in the gut microbiota, leading to systemic
disturbances, such as colorectal cancer, NAFLD, and liver cancer.
Our research group has investigated the association between periodontitis and diabetes and has conducted studies to elucidate the underlying
molecular mechanisms. Our study revealed that prolonged oral administration of Pg, a representative periodontal pathogen, in diabetic mice (db/db) resulted in destruction of the alveolar bone, which supports the teeth
and exacerbates hyperglycemia over time. Furthermore, a metaproteome
analysis of fecal samples from these mice revealed that the gut microbiota
underwent alterations due to the oral administration of Pg (Figure 1).
Proteome and metabolome analyses of mouse liver revealed reduced
glycogen content, elevated intermediate metabolites of glucose metabolism, decreased citric acid cycle-related enzymes, and increased expression of the glucose metabolism-related enzyme PCK1. Additionally, biochemical and histological analyses demonstrated enhanced expression of
PCK1, a molecule related to gluconeogenesis, and its transcription factor
FOXO1 in the livers of these mice (Figure 2).
These findings suggest an increase in glycogen breakdown and a decrease in energy metabolism within the mitochondria, suggesting that theingestion of Pg from the oral cavity leads to enhanced gluconeogenesis in
the liver via the enterohepatic pathway.

▍ Significance of the research and Future perspective
In this study, we elucidated a part of the mechanism by which the deterioration of the oral environment, influenced by the onset and progressionof periodontitis, comprehensively affects gut bacteria. This finding sheds

light on the adverse effects of periodontitis on the overall health. As ourunderstanding of these mechanisms deepens, we can expect advancements in our knowledge of the causes and processes of periodontitis,which is the most prevalent infectious disease worldwide. Additionally, thisimproved understanding may contribute to the development of new diagnostic methods and treatment approaches for lifestyle diseases that areexacerbated by deterioration of oral health.

850*ControlPg

Controle

Pg

Genus-level analyses

Blood glucose (mg/dl)

Life science

Abstract* *750

Pg

650

550

Control
Control

450350Prevotella
Pre d01 d7
7 1421 d2828
pred14d21

Anaerotruncus
Lactobacillus（Day）
Bacteroides
Clostridium
Oscillibacter
Eubacterium
Mu rib aculum
Mu cispirillum
Roseburia
Schaedlerella
RuminococcusAlistipes
Duncaniella
Porphyromonas
Parabacteroides
Lachnoclostridium
Pseudoflavonifractor
Butyrivibrio
Acetatifactor
Kineothrix
Dorea
Flavonifractor
Candidatus Amulumruptor
Lactonifactor
Butyricicoccus
Hungatella
Evtepia
Candidatus Arthromitus
Coprococcus
Bacillus
Blautia
AlloprevotellaParamuribaculum
Frisingicoccus
Jonquetella
Herbinix
Anaerostipes
Lachnobacterium
Fibrisoma
Lacrimispora
Bifidobacterium

Changes in intestinal flora by administration of periodontal bacteria
Control
30 days
Control

Pg 30
PgdaysPrevotella
Prevotella（文献24 より改変）

Fig.2

Oral administration of Pg increasedthe expression of gluconeogenesisrelated
molecule
in the liver ofPrevotella
was increasedby the (PKC1)
Pg administration.
diabetic mice

Each colorof thepie color
chart indicatesthechart
compositionof bacteria
at the genus level.
Fig.1
Eachof the pie
indicates
the composition
Prevotella
was increased
by genus
the Pg administration.
of bacteria
at thelevel.

Control
Control

Pg

PCK1

C

Immunohistochemical analysis of hepatic Pck1
 -actin
expression in Pg- and CMC-treated diabetic mice
H&E stain

Immunochemical staining

PCK1
Control

Control

PCK1
Pg

Pg

Fig.2 Oral administration of Pg increased the expression of gluconeogenesis-related molecule (PKC1) in the liver of diabetic mice.

P a t e n t Japanese Patent Application No.2023-145249
Kashiwagi, Yoichiro; Murakami, Shinya et al. Porphyromonas gingivalis induces entero-hepatic metabolic derangements with alteration of gut microbiota in
Tr e a t i s ea type 2 diabetes mouse model. Sci Rep. 2021;11(1):20016. doi: 10.1038/s41598-021-97868-2
URL
K e y w o r d periodontal disease, gut microbiota, diabetes, glucose metabolism disorder, oral-gut axis