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Liu S, Butler CA, Ayton S, Reynolds EC, Dashper SG. Porphyromonas gingivalis and the pathogenesis of Alzheimer's disease. Crit Rev Microbiol 2024; 50:127-137. [PMID: 36597758 DOI: 10.1080/1040841x.2022.2163613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 01/05/2023]
Abstract
The cause of Alzheimer's disease (AD), and the pathophysiological mechanisms involved, remain major unanswered questions in medical science. Oral bacteria, especially those species associated with chronic periodontitis and particularly Porphyromonas gingivalis, are being linked causally to AD pathophysiology in a subpopulation of susceptible individuals. P. gingivalis produces large amounts of proteolytic enzymes, haem and iron capture proteins, adhesins and internalins that are secreted and attached to the cell surface and concentrated onto outer membrane vesicles (OMVs). These enzymes and adhesive proteins have been shown to cause host tissue damage and stimulate inflammatory responses. The ecological and pathophysiological roles of P. gingivalis OMVs, their ability to disperse widely throughout the host and deliver functional proteins lead to the proposal that they may be the link between a P. gingivalis focal infection in the subgingivae during periodontitis and neurodegeneration in AD. P. gingivalis OMVs can cross the blood brain barrier and may accelerate AD-specific neuropathology by increasing neuroinflammation, plaque/tangle formation and dysregulation of iron homeostasis, thereby inducing ferroptosis leading to neuronal death and neurodegeneration.
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Affiliation(s)
- Sixin Liu
- School of Dentistry, University of Michigan, Ann Arbor, United States of America
| | - Catherine A Butler
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Australia
| | - Scott Ayton
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Eric C Reynolds
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Australia
| | - Stuart G Dashper
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Australia
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Li R, Wang J, Xiong W, Luo Y, Feng H, Zhou H, Peng Y, He Y, Ye Q. The oral-brain axis: can periodontal pathogens trigger the onset and progression of Alzheimer's disease? Front Microbiol 2024; 15:1358179. [PMID: 38362505 PMCID: PMC10868393 DOI: 10.3389/fmicb.2024.1358179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by a progressive cognitive decline. Sporadic AD, accounting for more than 95% of cases, may arise due to the influence of environmental factors. It was reported that periodontitis, a common oral ailment, shares several risk factors with AD, including advanced age, smoking, diabetes, and hypertension, among others. Periodontitis is an inflammatory disease triggered by dysbiosis of oral microorganisms, whereas Alzheimer's disease is characterized by neuroinflammation. Many studies have indicated that chronic inflammation can instigate brain AD-related pathologies, including amyloid-β plaques, Tau protein hyperphosphorylation, neuroinflammation, and neurodegeneration. The potential involvement of periodontal pathogens and/or their virulence factors in the onset and progression of AD by the oral-brain axis has garnered significant attention among researchers with ongoing investigations. This review has updated the periodontal pathogens potentially associated with AD, elucidating their impact on the central nervous system, immune response, and related pathological processes in the brain to provide valuable insights for future research on the oral-brain axis.
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Affiliation(s)
- Ruohan Li
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Junnan Wang
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wei Xiong
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yu Luo
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Huixian Feng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Heng Zhou
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Youjian Peng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yan He
- Institute of Regenerative and Translational Medicine, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, China
| | - Qingsong Ye
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
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Carballo Á, López-Dequidt I, Custodia A, Botelho J, Aramburu-Núñez M, Machado V, Pías-Peleteiro JM, Ouro A, Romaus-Sanjurjo D, Vázquez-Vázquez L, Jiménez-Martín I, Aguiar P, Rodríguez-Yáñez M, Aldrey JM, Blanco J, Castillo J, Sobrino T, Leira Y. Association of periodontitis with cognitive decline and its progression: Contribution of blood-based biomarkers of Alzheimer's disease to this relationship. J Clin Periodontol 2023; 50:1444-1454. [PMID: 37584311 DOI: 10.1111/jcpe.13861] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/12/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
AIM To assess whether periodontitis is associated with cognitive decline and its progression as well as with certain blood-based markers of Alzheimer's disease. MATERIALS AND METHODS Data from a 2-year follow-up prospective cohort study (n = 101) was analysed. Participants with a previous history of hypertension and aged ≥60 years were included in the analysis. All of them received a full-mouth periodontal examination and cognitive function assessments (Addenbrooke's Cognitive Examination (ACE) and Mini-Mental State Examination [MMSE]). Plasma levels of amyloid beta (Aβ)1-40 , Aβ1-42 , phosphorylated and total Tau (p-Tau and t-Tau) were determined at baseline, 12 and 24 months. RESULTS Periodontitis was associated with poor cognitive performance (MMSE: β = -1.5 [0.6]) and progression of cognitive impairment (hazard ratio [HR] = 1.8; 95% confidence interval: 1.0-3.1). Subjects with periodontitis showed greater baseline levels of p-Tau (1.6 [0.7] vs. 1.2 [0.2] pg/mL, p < .001) and Aβ1-40 (242.1 [77.3] vs. 208.2 [73.8] pg/mL, p = .036) compared with those without periodontitis. Concentrations of the latter protein also increased over time only in the periodontitis group (p = .005). CONCLUSIONS Periodontitis is associated with cognitive decline and its progression in elderly patients with a previous history of hypertension. Overexpression of p-Tau and Aβ1-40 may play a role in this association.
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Affiliation(s)
- Álvaro Carballo
- Periodontology Unit, Faculty of Odontology and Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Iria López-Dequidt
- Stroke Unit, Neurology Department, University Clinical Hospital, Santiago de Compostela, Spain
| | - Antía Custodia
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
| | - João Botelho
- Periodontology Department and Evidence-Based Hub, Clinical Research Unit, Centro de Investigação Interdisciplinar Egas Moniz, Instituto Universitário Egas Moniz - Cooperativa de Ensino Superior, Caparica, Portugal
| | - Marta Aramburu-Núñez
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
| | - Vanessa Machado
- Periodontology Department and Evidence-Based Hub, Clinical Research Unit, Centro de Investigação Interdisciplinar Egas Moniz, Instituto Universitário Egas Moniz - Cooperativa de Ensino Superior, Caparica, Portugal
| | - Juan Manuel Pías-Peleteiro
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
- Dementia Unit, Neurology Department, University Clinical Hospital, Santiago de Compostela, Spain
| | - Alberto Ouro
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
| | - Daniel Romaus-Sanjurjo
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
| | - Laura Vázquez-Vázquez
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
| | - Isabel Jiménez-Martín
- Dementia Unit, Neurology Department, University Clinical Hospital, Santiago de Compostela, Spain
| | - Pablo Aguiar
- Molecular Imaging Group, Department of Radiology, Faculty of Medicine and Center for Research In Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
- Nuclear Medicine Department and Molecular Imaging Group, University Clinical Hospital, Santiago de Compostela, Spain
| | - Manuel Rodríguez-Yáñez
- Stroke Unit, Neurology Department, University Clinical Hospital, Santiago de Compostela, Spain
| | - José Manuel Aldrey
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
- Dementia Unit, Neurology Department, University Clinical Hospital, Santiago de Compostela, Spain
| | - Juan Blanco
- Periodontology Unit, Faculty of Odontology and Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - José Castillo
- Neuroimaging and Biotechnology Laboratory (NOBEL) Group, Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
| | - Tomás Sobrino
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
| | - Yago Leira
- Periodontology Unit, Faculty of Odontology and Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
- NeuroAging Laboratory Group (NEURAL), Clinical Neurosciences Research Laboratories (LINC), Health Research Institute of Santiago de Compostela (IDIS), University Clinical Hospital, Santiago de Compostela, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Madrid, Spain
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Koyanagi K, Kataoka K, Yoshimatsu H, Fujihashi K, Miyake T. Human salivary protein-derived peptides specific-salivary SIgA antibodies enhanced by nasal double DNA adjuvant in mice play an essential role in preventing Porphyromonas gingivalis colonization: an in-vitro study. BMC Oral Health 2023; 23:123. [PMID: 36829152 PMCID: PMC9950703 DOI: 10.1186/s12903-023-02821-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 02/15/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND We previously showed that fimbriae-bore from Poryphyromonas gingivalis (Pg), one of the putative periodontopathogenic bacteria specifically bound to a peptide domain (stat23, prp21) shared on statherin or acidic proline-rich protein 1 (PRP1) molecule of human salivary proteins (HSPs). Here, we investigated whether the nasal administration of DNA plasmid expressing Flt3 ligand (pFL) and CpG oligodeoxynucleotide 1826 as double DNA adjuvant (dDA) with stat23 and prpr21 induces antigen (Ag)-specific salivary secretory IgA (SIgA) antibodies (Abs) in mice. Further, we examined that stat23- and prpr21-specific salivary SIgA Abs induced by dDA have an impact on Pg-binding to human whole saliva-coated hydroxyapatite beads (wsHAPs). MATERIAL AND METHODS C57BL/6N mice were nasally immunized with dDA plus sta23 or/and prp21 peptide as Ag four times at weekly intervals. Saliva was collected one week after the final immunization and was subjected to Ag-specific ELISA. To examine the functional applicability of Ag-specific SIgA Abs, SIgA-enriched saliva samples were subjected to Pg binding inhibition assay to wsHAPs. RESULTS Significantly elevated levels of salivary SIgA Ab to stat23 or prp21 were seen in mice given nasal stat23 or prp21 with dDA compared to those in mice given Ag alone. Of interest, mice nasally given the mixture of stat23 and prp21 as double Ags plus dDA, resulted in both stat23- and prp21-specific salivary SIgA Ab responses, which are mediated through significantly increased numbers of CD11c+ dendritic cell populations and markedly elevated Th1 and Th2 cytokines production by CD4+ T cells in the mucosal inductive and effector tissues. The SIgA Ab-enriched saliva showed significantly reduced numbers of live Pg cells binding to wsHAPs as compared with those in mice given double Ags without dDA or naïve mice. Additionally, saliva from IgA-deficient mice given nasal double Ags plus dDA indicated no decrease of live Pg binding to wsHAPs. CONCLUSION These findings show that HSP-derived peptides-specific salivary SIgA Abs induced by nasal administration of stat23 and prp21 peptides plus dDA, play an essential role in preventing Pg attachment and colonization on the surface of teeth, suggesting a potency that the SIgA may interrupt and mask fimbriae-binding domains in HSPs on the teeth.
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Affiliation(s)
- Kayo Koyanagi
- Department of Preventive and Community Dentistry, Graduate School of Dentistry, Osaka Dental University, 1-8 Kuzuha Hanazono-Cho, Hirakata-Shi, Osaka, 573-1121, Japan
| | - Kosuke Kataoka
- Department of Preventive and Community Dentistry, Graduate School of Dentistry, Osaka Dental University, 1-8 Kuzuha Hanazono-Cho, Hirakata-Shi, Osaka, 573-1121, Japan. .,Department of Oral Health Science and Social Welfare, Graduate School of Oral Sciences, Tokushima University, 3-18-15 Kuramoto-Cho, Tokushima-Shi, Tokushima, 770-8504, Japan.
| | - Hideki Yoshimatsu
- Department of Preventive and Community Dentistry, Graduate School of Dentistry, Osaka Dental University, 1-8 Kuzuha Hanazono-Cho, Hirakata-Shi, Osaka, 573-1121, Japan
| | - Kohtaro Fujihashi
- Department of Human Mucosal Vaccinology, Chiba University Hospital, Research Institute of Disaster Medicine, Chiba University, 1-8-1 Inohana, Chuo-Ku, Chiba-Shi, Chiba, Japan.,Division of Mucosal Vaccine, International Vaccine Design Center, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shiroganedai, Minato-Ku, Tokyo, 108-8639, Japan.,Department of Pediatric Dentistry, School of Dentistry, The University of Alabama at Birmingham, 1919 7Th Avenue South, Birmingham, AL, 35233, USA
| | - Tatsuro Miyake
- Department of Preventive and Community Dentistry, Graduate School of Dentistry, Osaka Dental University, 1-8 Kuzuha Hanazono-Cho, Hirakata-Shi, Osaka, 573-1121, Japan
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Lei S, Li J, Yu J, Li F, Pan Y, Chen X, Ma C, Zhao W, Tang X. Porphyromonas gingivalis bacteremia increases the permeability of the blood-brain barrier via the Mfsd2a/Caveolin-1 mediated transcytosis pathway. Int J Oral Sci 2023; 15:3. [PMID: 36631446 PMCID: PMC9834243 DOI: 10.1038/s41368-022-00215-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 01/13/2023] Open
Abstract
Bacteremia induced by periodontal infection is an important factor for periodontitis to threaten general health. P. gingivalis DNA/virulence factors have been found in the brain tissues from patients with Alzheimer's disease (AD). The blood-brain barrier (BBB) is essential for keeping toxic substances from entering brain tissues. However, the effect of P. gingivalis bacteremia on BBB permeability and its underlying mechanism remains unclear. In the present study, rats were injected by tail vein with P. gingivalis three times a week for eight weeks to induce bacteremia. An in vitro BBB model infected with P. gingivalis was also established. We found that the infiltration of Evans blue dye and Albumin protein deposition in the rat brain tissues were increased in the rat brain tissues with P. gingivalis bacteremia and P. gingivalis could pass through the in vitro BBB model. Caveolae were detected after P. gingivalis infection in BMECs both in vivo and in vitro. Caveolin-1 (Cav-1) expression was enhanced after P. gingivalis infection. Downregulation of Cav-1 rescued P. gingivalis-enhanced BMECs permeability. We further found P. gingivalis-gingipain could be colocalized with Cav-1 and the strong hydrogen bonding between Cav-1 and arg-specific-gingipain (RgpA) were detected. Moreover, P. gingivalis significantly inhibited the major facilitator superfamily domain containing 2a (Mfsd2a) expression. Mfsd2a overexpression reversed P. gingivalis-increased BMECs permeability and Cav-1 expression. These results revealed that Mfsd2a/Cav-1 mediated transcytosis is a key pathway governing BBB BMECs permeability induced by P. gingivalis, which may contribute to P. gingivalis/virulence factors entrance and the subsequent neurological impairments.
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Affiliation(s)
- Shuang Lei
- Department of Periodontics, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
- Department of Pediatric Dentistry, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
| | - Jian Li
- Department of Preventive Dentistry, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, Shenyang, China
| | - Jingjun Yu
- Department of Periodontics, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
| | - Fulong Li
- Department of Periodontics, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
| | - Yaping Pan
- Department of Periodontics, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
| | - Xu Chen
- Department of Pediatric Dentistry, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
| | - Chunliang Ma
- Department of Periodontics, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China
| | - Weidong Zhao
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, China Medical University, 77 Puhe Road, Shenbei New District, Shenyang, China
| | - Xiaolin Tang
- Department of Periodontics, School and Hospital of Stomatology, Liaoning Provincial Key Laboratory of Oral Disease, China Medical University, No. 117, Nanjing North Street, Heping District, Shenyang, China.
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Salhi L, Al Taep Y, Salmon E, Van Hede D, Lambert F. How Periodontitis or Periodontal Bacteria Can Influence Alzheimer's Disease Features? A Systematic Review of Pre-Clinical Studies. J Alzheimers Dis 2023; 96:979-1010. [PMID: 37927257 PMCID: PMC10741373 DOI: 10.3233/jad-230478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND The negative effects of periodontitis on systemic diseases, including diabetes, cardiovascular diseases, and Alzheimer's disease (AD), have been widely described. OBJECTIVE This systematic review aimed to gather the current understanding of the pathophysiological mechanisms linking periodontitis to AD. METHODS An electronic systematic search of the PubMed/MEDLINE, Scopus, and Embase databases was performed using the following PECO question: How can periodontitis or periodontal bacteria influence Alzheimer's disease features?". Only preclinical studies exploring the biological links between periodontitis and AD pathology were included. This study was registered at the International Prospective Register of Systematic Reviews (PROSPERO), and the Syrcle and Camarades protocols were used to assess the risk of bias. RESULTS After a systematic screening of titles and abstracts (n = 3,307), thirty-six titles were selected for abstract reading, of which 13 were excluded (k = 1), resulting in the inclusion of 23 articles. Oral or systemic exposure to periodontopathogens or their byproducts is responsible for both in situ brain manifestations and systemic effects. Significant elevated rates of cytokines and amyloid peptides (Aβ) and derivate products were found in both serum and brain. Additionally, in infected animals, hyperphosphorylation of tau protein, hippocampal microgliosis, and neuronal death were observed. Exposure to periodontal infection negatively impairs cognitive behavior, leading to memory decline. CONCLUSIONS Systemic inflammation and brain metastatic infections induced by periodontal pathogens contribute to neuroinflammation, amyloidosis, and tau phosphorylation, leading to brain damage and subsequent cognitive impairment.
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Affiliation(s)
- Leila Salhi
- Department of Periodontology, Oro-Dental and Implant Surgery, University Hospital of Liège, Liège, Belgium
| | - Yaman Al Taep
- Department of Periodontology, Oro-Dental and Implant Surgery, University Hospital of Liège, Liège, Belgium
| | - Eric Salmon
- Department of Neurology - Memory Clinic, University Hospital of Liège, Liège, Belgium
- GIGA Cyclotron Research Center, University of Liege, Liege, Belgium
| | - Dorien Van Hede
- Department of Periodontology, Oro-Dental and Implant Surgery, University Hospital of Liège, Liège, Belgium
| | - France Lambert
- Department of Periodontology, Oro-Dental and Implant Surgery, University Hospital of Liège, Liège, Belgium
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Zhang Z, Zhou J, Xia D, Wang Z. Editorial: Association between oral microbiota dysbiosis and the development of systemic conditions. Front Cell Infect Microbiol 2023; 13:1204103. [PMID: 37143742 PMCID: PMC10152363 DOI: 10.3389/fcimb.2023.1204103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 05/06/2023] Open
Affiliation(s)
- Zheng Zhang
- Tianjin Stomatological Hospital, School of Medicine, Nankai University, Tianjin, China
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin, China
- *Correspondence: Zuomin Wang, ; Dong Xia, ; Zheng Zhang,
| | - Jian Zhou
- The School and Hospital of Stomatology, Capital Medical University, Beijing, China
| | - Dong Xia
- Royal Veterinary College, University of London, London, United Kingdom
- *Correspondence: Zuomin Wang, ; Dong Xia, ; Zheng Zhang,
| | - Zuomin Wang
- Department of Stomatology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
- *Correspondence: Zuomin Wang, ; Dong Xia, ; Zheng Zhang,
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Liu L, Geng Y, Xiong C. Impact of Porphyromonas gingivalis-odontogenic infection on the pathogenesis of non-alcoholic fatty liver disease. Ann Med 2023; 55:2255825. [PMID: 37708866 PMCID: PMC10503456 DOI: 10.1080/07853890.2023.2255825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/15/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
Aim: Non-alcoholic fatty liver disease is characterized by diffuse hepatic steatosis and has quickly risen to become the most prevalent chronic liver disease. Its incidence is increasing yearly, but the pathogenesis is still not fully understood. Porphyromonas gingivalis (P. gingivalis) is a major pathogen widely prevalent in periodontitis patients. Its infection has been reported to be a risk factor for developing insulin resistance, non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and metabolic syndrome. The aim of this review is to evaluate the association between P. gingivalis infection and NAFLD, identify the possible etiopathogenetic mechanisms, and raise public awareness of oral health to prevent and improve NAFLD.Methods: After searching in PubMed and Web of Science databases using 'Porphyromonas gingivalis', 'non-alcoholic fatty liver disease', and 'hepatic steatosis' as keywords, studies related were compiled and examined.Results: P. gingivalis infection is a direct risk factor for NAFLD based on clinical and basic research. Moreover, it induces systematic changes and systemic abnormalities by disrupting metabolic, inflammatory, and immunologic homeostasis.Conclusion: P. gingivalis-odontogenic infection promotes the occurrence and development of NAFLD. Further concerns are needed to emphasize oral health and maintain good oral hygiene for the prevention and treatment of NAFLD.
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Affiliation(s)
- Linbo Liu
- Department of Clinical Laboratory, Yulin No.2 Hospital, Yulin, Shaanxi, China
| | - Yan Geng
- Department of Clinical Laboratory, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Chaoliang Xiong
- Department of Clinical Laboratory, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China
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Treponema denticola Induces Neuronal Apoptosis by Promoting Amyloid-β Accumulation in Mice. Pathogens 2022; 11:pathogens11101150. [PMID: 36297207 PMCID: PMC9610539 DOI: 10.3390/pathogens11101150] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Neuronal apoptosis is a major contributor to Alzheimer's disease (AD). Periodontitis is a significant risk factor for AD. The periodontal pathogens Porphyromonas gingivalis and Treponema denticola have been shown to initiate the hallmark pathologies and behavioral symptoms of AD. Studies have found that T. denticola infection induced Tau hyperphosphorylation and amyloid β accumulation in the hippocampi of mice. Aβ accumulation is closely associated with neuronal apoptosis. However, the roles of T. denticola in neuronal apoptosis remain unclear and its roles in AD pathology need further study. Objective: This study aimed to investigate whether oral infection with T. denticola induced alveolar bone loss and neuronal apoptosis in mice. Methods: C57BL/6 mice were orally administered with T. denticola, Micro-CT was employed to assess the alveolar bone resorption. Western blotting, quantitative PCR, and TUNEL staining were utilized to detect the apoptosis-associated changes in mouse hippocampi. N2a were co-cultured with T. denticola to verify in vivo results. Results: Mice infected with T. denticola exhibited more alveolar bone loss compared with the control mice. T. denticola oral infection induced neuronal apoptosis in hippocampi of mice. Consistent results of the apoptosis-associated protein expression were observed in N2a cells treated with T. denticola and Aβ1-42 in vitro. However, the Aβ inhibitor reversed these results, suggesting that Aβ1-42 mediates T. denticola infection-induced neuronal apoptosis. Conclusions: This study found that oral infected T. denticola caused alveolar bone loss, and induced neuronal apoptosis by promoting Aβ accumulation in mice, providing evidence for the link between periodontitis and AD.
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Sabbagh MN, Decourt B. COR388 (atuzaginstat): an investigational gingipain inhibitor for the treatment of Alzheimer disease. Expert Opin Investig Drugs 2022; 31:987-993. [PMID: 36003033 PMCID: PMC10275298 DOI: 10.1080/13543784.2022.2117605] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/23/2022] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Evidence from in vitro and in vivo studies demonstrates that amyloid beta (Aβ) oligomers have potent, broad-spectrum antimicrobial properties created by fibrils that entrap pathogens and disrupt their membranes. Data suggest that Aβ may play a protective role in the innate immune response to microbial infections and that Aβ in the brain plays a damaging role when the inflammatory response is not well controlled. AREAS COVERED This paper describes the relationship between periodontal disease and Alzheimer disease (AD), the role of Porphyromonas gingivalis and its secreted gingipains in AD, and the potential of the gingipain inhibitor atuzaginstat (COR388) to modulate AD neuropathologies. EXPERT OPINION P. gingivalis is opsonized by Aβ42, is capable of entering the brain, and is an accelerant of neuropathologies in rodent models of AD. Thus, in our opinion, this bacteria is highly likely to be a pathogen capable of initiating or precipitating the progression of AD, which agrees with the pathogen hypothesis of clinical AD development.
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Affiliation(s)
- Marwan N. Sabbagh
- Department of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix Arizona, USA
| | - Boris Decourt
- Translational Neuroscience Lab, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada, USA
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11
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Gong T, Chen Q, Mao H, Zhang Y, Ren H, Xu M, Chen H, Yang D. Outer membrane vesicles of Porphyromonas gingivalis trigger NLRP3 inflammasome and induce neuroinflammation, tau phosphorylation, and memory dysfunction in mice. Front Cell Infect Microbiol 2022; 12:925435. [PMID: 36017373 PMCID: PMC9397999 DOI: 10.3389/fcimb.2022.925435] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundPorphyromonas gingivalis (Pg), the keystone pathogen in chronic periodontitis, is reported to initiate Alzheimer’s disease pathologies in preclinical studies. However, the specific mechanisms and signaling pathways acting on the brain still need to be further explored. Outer membrane vesicles are derived from Gram-negative bacteria and contain many virulence factors of bacteria. We hypothesized that outer membrane vesicles are an important weapon of Porphyromonas gingivalis to initiate Alzheimer’s disease pathologies.MethodsThe outer membrane vesicles of Porphyromonas gingivalis (Pg OMVs, 4 mg/kg) or saline were delivered to 14-month-old mice by oral gavage every other day for eight weeks. Behavioral alterations were assessed by the open field test, Morris water maze, and Y-maze test. Blood–brain barrier permeability, neuroinflammation, tau phosphorylation, and NLRP3 inflammasome-related protein were analyzed.ResultsPg OMVs impaired memory and learning ability of mice and decreased tight junction–related gene expression ZO-1, occludin, claudin-5, and occludin protein expression in the hippocampus. Pg OMVs could be detected in the hippocampus and cortex three days after oral gavage. Furthermore, Pg OMVs activated both astrocytes and microglia and elevated IL-1β, tau phosphorylation on the Thr231 site, and NLRP3 inflammasome–related protein expression in the hippocampus. In in vitro studies, Pg OMV (5 µg/ml) stimulation increased the mRNA and immunofluorescence of NLRP3 in BV2 microglia, which were significantly inhibited by the NLRP3 inhibitor MCC950. In contrast, the tau phosphorylation in N2a neurons was enhanced after treatment with conditioned media from Pg OMV-stimulated microglia, which was attenuated after pretreatment with MCC950.ConclusionsThese results indicate that Pg OMVs prompt memory dysfunction, neuroinflammation, and tau phosphorylation and trigger NLRP3 inflammasome in the brain of middle-aged mice. We propose that Pg OMVs play an important role in activating neuroinflammation in the AD-like pathology triggered by Porphyromonas gingivalis, and NLRP3 inflammasome activation is a possible mechanism.
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Affiliation(s)
- Ting Gong
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Qi Chen
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Hongchen Mao
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Yao Zhang
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Huan Ren
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Mengmeng Xu
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Hong Chen
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Deqin Yang
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
- *Correspondence: Deqin Yang,
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12
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Huang YF, Yang HW, Lin-Shiau SY. Novel regimens of phytopolyphenols with cisplatin or memantine and ZnSO4 for synergistic inhibition of growth and gingipains of the cultured Porphyromonas gingivalis. J Dent Sci 2022; 17:1796-1801. [PMID: 36299354 PMCID: PMC9588875 DOI: 10.1016/j.jds.2022.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 06/19/2022] [Indexed: 11/17/2022] Open
Abstract
Background/purpose Porphyromonas gingivalis (P.g.) played a keystone pathogen not only in initiation and progression of periodontitis but also as a risk factor involved in systemic diseases (Alzheimer’s disease, cancers, diabetes, osteoporosis etc.). Developments of effective and safe drugs to inhibit P.g. growth are urgent. In this study, we aimed at approaching novel regimens so called (PTM) by combination of repurposing drugs including phytopolyphenols (P) (curcumin, tea polyphenols), targeting drugs (T) such as cisplatin or memantine and metal ions(M) (ZnSO4). Materials and methods The synergistic (combination Index (CI) < 1) antiproliferation and anti-protease efficacies (IC50) of novel regimens on cultured P.g. were evaluated by OD600 and colorimetric method respectively. Results The results obtained revealed that these novel regimens (PTM) synergistically (combination index, CI < 1) exerted not only antiproliferative but also anti-gingipain protease effects of P.g. The concentrations for 50% inhibition (IC50) of novel regimens on P.g. growth and gingipains were greatly decreased as compared with those of cisplatin and memantine alone. Conclusion Since these novel regimens exerted potent anti-bacterial effects on both planktonic and biofilm P.g., it is encouraged for further preclinical and clinical trials.
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Affiliation(s)
- Yu-Feng Huang
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Stomatology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Hui-Wen Yang
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Stomatology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Shoei-Yn Lin-Shiau
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Corresponding author. School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, 40201, Taiwan.
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2,3,5,4′-Tetrahydroxystilbene-2-O-β-glucoside Attenuates Reactive Oxygen Species-Dependent Inflammation and Apoptosis in Porphyromonas gingivalis-Infected Brain Endothelial Cells. Antioxidants (Basel) 2022; 11:antiox11040740. [PMID: 35453424 PMCID: PMC9024880 DOI: 10.3390/antiox11040740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/01/2022] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
We recently reported that the periodontopathic bacteria Porphyromonas gingivalis (P. gingivalis) initiates an inflammatory cascade that disrupts the balance of reactive oxygen species (ROS), resulting in apoptotic cell death in brain endothelial cells. An extract from Polygonum multiflorum Thunb., 2,3,5,4′-Tetrahydroxystilbene-2-O-β-glucoside (THSG) has been well-reported to diminish the inflammation in many disease models. However, the effects of THSG in the area of the brain–oral axis is unknown. In this study, we examined the effects of THSG in P. gingivalis-stimulated inflammatory response and apoptotic cell death in brain endothelial cells. THSG treatment remarkably lessened the upregulation of IL-1β and TNF-α proteins in bEnd.3 cells infected with P. gingivalis. Treatment of THSG further ameliorated brain endothelial cell death, including apoptosis caused by P. gingivalis. Moreover, the present study showed that the inhibitory effects on NF-κB p65 and antiapoptotic properties of THSG is through inhibiting the ROS pathway. Importantly, the ROS inhibitory potency of THSG is similar to a ROS scavenger N-Acetyl-L-Cysteine (NAC) and NADPH oxidase inhibitor apocynin. Furthermore, the protective effect of THSG from P. gingivalis infection was further confirmed in primary mouse brain endothelial cells. Taken together, this study indicates that THSG attenuates an ROS-dependent inflammatory response and cell apoptosis in P. gingivalis-infected brain endothelial cells. Our results also suggest that THSG could be a potential herbal medicine to prevent the risk of developing cerebrovascular diseases from infection of periodontal bacteria.
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Seymour T, Zhang J. Porphyromonas Gingivalis in the Pathogenesis of Alzheimer’s Disease and Its Therapeutic Target. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2022; 7:45-53. [DOI: 10.14218/jerp.2021.00030] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Leaky Gum: The Revisited Origin of Systemic Diseases. Cells 2022; 11:cells11071079. [PMID: 35406643 PMCID: PMC8997512 DOI: 10.3390/cells11071079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/10/2022] Open
Abstract
The oral cavity is the gateway for microorganisms into your body where they disseminate not only to the directly connected respiratory and digestive tracts but also to the many remote organs. Oral microbiota, travelling to the end of the intestine and circulating in our bodies through blood vessels, not only affect a gut microbiome profile but also lead to many systemic diseases. By gathering information accumulated from the era of focal infection theory to the age of revolution in microbiome research, we propose a pivotal role of “leaky gum”, as an analogy of “leaky gut”, to underscore the importance of the oral cavity in systemic health. The oral cavity has unique structures, the gingival sulcus (GS) and the junctional epithelium (JE) below the GS, which are rarely found anywhere else in our body. The JE is attached to the tooth enamel and cementum by hemidesmosome (HD), which is structurally weaker than desmosome and is, thus, vulnerable to microbial infiltration. In the GS, microbial biofilms can build up for life, unlike the biofilms on the skin and intestinal mucosa that fall off by the natural process. Thus, we emphasize that the GS and the JE are the weakest leaky point for microbes to invade the human body, making the leaky gum just as important as, or even more important than, the leaky gut.
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16
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Jungbauer G, Stähli A, Zhu X, Auber Alberi L, Sculean A, Eick S. Periodontal microorganisms and Alzheimer disease - A causative relationship? Periodontol 2000 2022; 89:59-82. [PMID: 35244967 PMCID: PMC9314828 DOI: 10.1111/prd.12429] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/07/2021] [Accepted: 12/21/2021] [Indexed: 01/10/2023]
Abstract
In the initiation or exacerbation of Alzheimer disease, the dissemination of oral microorganisms into the brain tissue or the low‐level systemic inflammation have been speculated to play a role. However, the impact of oral microorganisms, such as Porphyromonas gingivalis, on the pathogenesis of Alzheimer disease and the potential causative relationship is still unclear. The present review has critically reviewed the literature by examining the following aspects: (a) the oral microbiome and the immune response in the elderly population, (b) human studies on the association between periodontal and gut microorganisms and Alzheimer disease, (c) animal and in vitro studies on microorganisms and Alzheimer disease, and (d) preventive and therapeutic approaches. Factors contributing to microbial dysbiosis seem to be aging, local inflammation, systemic diseases, wearing of dentures, living in nursing homes and no access to adequate oral hygiene measures. Porphyromonas gingivalis was detectable in post‐mortem brain samples. Microbiome analyses of saliva samples or oral biofilms showed a decreased microbial diversity and a different composition in Alzheimer disease compared to cognitively healthy subjects. Many in‐vitro and animal studies underline the potential of P gingivalis to induce Alzheimer disease‐related alterations. In animal models, recurring applications of P gingivalis or its components increased pro‐inflammatory mediators and β‐amyloid in the brain and deteriorated the animals' cognitive performance. Since periodontitis is the result of a disturbed microbial homoeostasis, an effect of periodontal therapy on the oral microbiome and host response related to cognitive parameters may be suggested and should be elucidated in further clinical trials.
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Affiliation(s)
- Gert Jungbauer
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.,Private Dental Practice, Straubing, Germany
| | - Alexandra Stähli
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Xilei Zhu
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | | | - Anton Sculean
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Sigrun Eick
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
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17
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Tang Z, Cheng X, Su X, Wu L, Cai Q, Wu H. Treponema denticola Induces Alzheimer-Like Tau Hyperphosphorylation by Activating Hippocampal Neuroinflammation in Mice. J Dent Res 2022; 101:992-1001. [PMID: 35193423 DOI: 10.1177/00220345221076772] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Alzheimer's disease (AD) is the most common type of dementia. Tau hyperphosphorylation and amyloid β (Aβ) deposition are the key pathological hallmarks of AD. Recent studies have shown that periodontitis is a significant risk factor for AD. The periodontal pathogen Porphyromonas gingivalis and its virulence factors have been shown to initiate and promote the hallmark pathologies and behavioral symptoms of AD. A possible link between Treponema denticola, another main periodontal pathogen, and AD has been reported. However, the role of T. denticola in AD pathogenesis is still unclear, and whether T. denticola and P. gingivalis exert a synergistic effect to promote AD development needs to be further studied. In this study, we investigated whether oral infection with T. denticola caused tau hyperphosphorylation in the hippocampi of mice and explored the underlying mechanisms. Orally administered T. denticola induced alveolar bone resorption, colonized brain tissues, and increased the activity of the phosphokinase GSK3β by activating neuroinflammation in the hippocampus, thus promoting the hyperphosphorylation of the tau protein at Ser396, Thr181, and Thr231 in mice. An in vitro study with BV2 and N2a cell models of T. denticola invasion also verified the role of this pathogen in tau phosphorylation. T. denticola and P. gingivalis were not found to exert a synergistic effect on tau phosphorylation. In summary, these findings provide new insight into the important role of T. denticola in AD pathogenesis, providing biological connections between periodontal diseases and AD.
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Affiliation(s)
- Z Tang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Cheng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Su
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - L Wu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Q Cai
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - H Wu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Olsen I. Porphyromonas gingivalis-Induced Neuroinflammation in Alzheimer's Disease. Front Neurosci 2021; 15:691016. [PMID: 34720846 PMCID: PMC8551391 DOI: 10.3389/fnins.2021.691016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
"Chronic" periodontitis and its keystone pathogen Porphyromonas gingivalis have repeatedly been associated with Alzheimer's disease (AD). Pathological hallmarks in AD are brain accumulations of amyloid-beta and neurofibrillary tangles consisting of aggregated and hyperphosphorylated tau. In addition, neuroinflammation induced by P. gingivalis has increasingly been recognized as a factor in the pathogenesis of AD. The present mini-review discusses possible mechanisms for the induction of neuroinflammation by P. gingivalis in AD, involving factors such as pro-inflammatory mediators, amyloid-beta, tau, microglia, cathepsin B, and protein kinase R. Inflammagens of P. gingivalis such as lipopolysaccharide and gingipains are also discussed.
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Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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19
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Olsen I. Possible effects of Porphyromonas gingivalis on the blood-brain barrier in Alzheimer's disease. Expert Rev Anti Infect Ther 2021; 19:1367-1371. [PMID: 33938372 DOI: 10.1080/14787210.2021.1925540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway,
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20
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Su X, Tang Z, Lu Z, Liu Y, He W, Jiang J, Zhang Y, Wu H. Oral Treponema denticola Infection Induces Aβ 1-40 and Aβ 1-42 Accumulation in the Hippocampus of C57BL/6 Mice. J Mol Neurosci 2021; 71:1506-1514. [PMID: 33763842 DOI: 10.1007/s12031-021-01827-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/05/2021] [Indexed: 02/05/2023]
Abstract
Accumulation of amyloid-β (Aβ) in the brain is a central component of pathology in Alzheimer's disease. A growing volume of evidence demonstrates close associations between periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) and Treponema denticola (T. denticola) and AD. However, the effect and mechanisms of T. denticola on accumulation of Aβ remain to be unclear. In this study, we demonstrated that T. denticola was able to enter the brain and act directly on nerve cells resulting in intra- and extracellular Aβ1-40 and Aβ1-42 accumulation in the hippocampus of C57BL/6 mice by selectively activating both β-secretase and γ-secretase. Furthermore, both KMI1303, an inhibitor of β-secretase, as well as DAPT, an inhibitor of γ- secretase, were found to be able to inhibit the effect of T. denticola on Aβ accumulation in N2a neuronal cells. Overall, it is concluded that T. denticola increases the expression of Aβ1-42 and Aβ1-40 by its regulation on beta-site amyloid precursor protein cleaving enzyme-1 and presenilin 1.
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Affiliation(s)
- Xinyi Su
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Zhiqun Tang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Zhiyue Lu
- Department of Stomatology Beijing Hospital, Institute of Geriatric Medicine, National Center of Gerontology, Beijing, 100000, China
| | - Yuqiu Liu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Wanzhi He
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Jiapei Jiang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Yifan Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Hongkun Wu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, Sichuan, China.
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