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Isola G, Santonocito S, Lupi SM, Polizzi A, Sclafani R, Patini R, Marchetti E. Periodontal Health and Disease in the Context of Systemic Diseases. Mediators Inflamm 2023; 2023:9720947. [PMID: 37214190 PMCID: PMC10199803 DOI: 10.1155/2023/9720947] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 09/04/2022] [Accepted: 04/07/2023] [Indexed: 05/24/2023] Open
Abstract
During recent years, considerable progress has been made in understanding the etiopathogenesis of periodontitis in its various forms and their interactions with the host. Furthermore, a number of reports have highlighted the importance of oral health and disease in systemic conditions, especially cardiovascular diseases and diabetes. In this regard, research has attempted to explain the role of periodontitis in promoting alteration in distant sites and organs. Recently, DNA sequencing studies have revealed how oral infections can occur in distant sites such as the colon, reproductive tissues, metabolic diseases, and atheromas. The objective of this review is to describe and update the emerging evidence and knowledge regarding the association between periodontitis and systemic disease and to analyse the evidence that has reported periodontitis as a risk factor for the development of various forms of systemic diseases in order to provide a better understanding of the possible shared etiopathogenetic pathways between periodontitis and the different forms of systemic diseases.
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Affiliation(s)
- Gaetano Isola
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, Catania, Italy
| | - Simona Santonocito
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, Catania, Italy
| | - Saturnino Marco Lupi
- Department of Clinical Surgical, Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy
| | - Alessandro Polizzi
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, Catania, Italy
| | - Rossana Sclafani
- Department of General Surgery and Surgical-Medical Specialties, School of Dentistry, University of Catania, Catania, Italy
| | - Romeo Patini
- Institute of Dentistry and Maxillofacial Surgery, Fondazione Policlinico Universitario Agostino Gemelli, Catholic University of the Sacred Heart, Rome, Italy
| | - Enrico Marchetti
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
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Cheataini F, Ballout N, Al Sagheer T. The effect of neuroinflammation on the cerebral metabolism at baseline and after neural stimulation in neurodegenerative diseases. J Neurosci Res 2023. [PMID: 37186320 DOI: 10.1002/jnr.25198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 05/17/2023]
Abstract
Neuroinflammation is a reaction of nervous tissue to an attack caused by an infection, a toxin, or a neurodegenerative disease. It involves brain metabolism adaptation in order to meet the increased energy needs of glial cell activation, but the nature of these adaptations is still unknown. Increasing interest concerning neuroinflammation leads to the identification of its role in neurodegenerative diseases. Few reports studied the effect of metabolic alteration on neuroinflammation. Metabolic damage initiates a pro-inflammatory response by microglial activation. Moreover, the exact neuroinflammation effect on cerebral cell metabolism remains unknown. In this study, we reviewed systematically the neuroinflammation effect in animal models' brains. All articles showing the relationship of neuroinflammation with brain metabolism, or with neuronal stimulation in neurodegenerative diseases were considered. Moreover, this review examines also the mitochondrial damage effect in neurodegeneration diseases. Then, different biosensors are classified regarding their importance in the determination of metabolite change. Finally, some therapeutic drugs inhibiting neuroinflammation are cited. Neuroinflammation increases lymphocyte infiltration and cytokines' overproduction, altering cellular energy homeostasis. This review demonstrates the importance of neuroinflammation as a mediator of disease progression. Further, the spread of depolarization effects pro-inflammatory genes expression and microglial activation, which contribute to the degeneration of neurons, paving the road to better management and treatment of neurodegenerative diseases.
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Affiliation(s)
- Fatima Cheataini
- Neuroscience Research Center (NRC), Faculty of Medical Science, Lebanese University, Hadath, Beirut, Lebanon
| | - Nissrine Ballout
- Neuroscience Research Center (NRC), Faculty of Medical Science, Lebanese University, Hadath, Beirut, Lebanon
| | - Tareq Al Sagheer
- Neuroscience Research Center (NRC), Faculty of Medical Science, Lebanese University, Hadath, Beirut, Lebanon
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Guo H, Li B, Yao H, Liu D, Chen R, Zhou S, Ji Y, Zeng L, Du M. Profiling the oral microbiomes in patients with Alzheimer's disease. Oral Dis 2023; 29:1341-1355. [PMID: 34931394 DOI: 10.1111/odi.14110] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/10/2021] [Accepted: 12/16/2021] [Indexed: 01/15/2023]
Abstract
OBJECTIVES To analyse the characteristics of the oral microbiomes and expected to find biomarkers about Alzheimer's disease (AD). SUBJECTS AND METHODS AD patients (n = 26) and cognitive intact people (n = 26) were examined for cognition, depression, oral health and collected saliva and gingival crevicular fluid (GCF) in the morning. Full-length 16S rRNA gene was amplified and sequencing was performed using the PacBio platform. RESULTS The predominant bacterium of salivary microbiome and periodontal microbiome from AD patients was Streptococcus oralis and Porphyromonas gingivalis, respectively. With respect to β diversity analysis, there was a significance difference in periodontal microbiome between AD patients and cognitively intact subjects. The relative abundance of Veillonella parvula significantly increased in oral microbiomes from AD patients. Interestingly, the dominant species were different between early-onset AD and late-onset AD patients. Moreover, the predominant species were changed as the clinical severity of AD. Furthermore, the correlation analysis revealed that V. parvula was associated with AD in both saliva and GCF and that P. gingivalis was associated with AD only in GCF. CONCLUSIONS In this study, the microbiome community of oral microbes was altered in AD patients and periodontal microbiome was sensitive to cognition changes. Moreover, V. parvula and P. gingivalis were associated with AD.
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Affiliation(s)
- Haiying Guo
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Biao Li
- Wuhan Mental Health Center, Wuhan, Hubei, China
| | - Hantao Yao
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Danfeng Liu
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Rourong Chen
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Shuhui Zhou
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Yaoting Ji
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
| | - Lin Zeng
- Wuhan Mental Health Center, Wuhan, Hubei, China
| | - Minquan Du
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
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Jin R, Ning X, Liu X, Zhao Y, Ye G. Porphyromonas gingivalis-induced periodontitis could contribute to cognitive impairment in Sprague–Dawley rats via the P38 MAPK signaling pathway. Front Cell Neurosci 2023; 17:1141339. [PMID: 37056710 PMCID: PMC10086325 DOI: 10.3389/fncel.2023.1141339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
BackgroundPeriodontitis is one of the most common oral diseases and has been shown to be a risk factor for systemic diseases. Our aim was to investigate the relationship between periodontitis and cognitive impairment and to explore the role of the P38 MAPK signaling pathway in this process.MethodsWe established a periodontitis model by ligating the first molars of SD rats with silk thread and injecting Porphyromonas gingivalis (P. gingivalis) or P. gingivalis plus the P38 MAPK inhibitor SB203580 at the same time for ten weeks. We assessed alveolar bone resorption and spatial learning and memory using microcomputed tomography and the Morris water maze test, respectively. We used transcriptome sequencing to explore the genetic differences between the groups. The gingival tissue, peripheral blood and hippocampal tissue were assessed for the cytokines TNF-α, IL-1β, IL-6, IL-8 and C reactive protein (CRP) with enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT–PCR). We observed the presence of P. gingivalis in the hippocampus of rats by paraffin-fluorescence in situ hybridization (FISH). We determined the activation of microglia by immunofluorescence. Finally, Western blot analysis was employed to determine the expression of amyloid precursor protein (APP), β-site APP-cleaving enzyme 1 (BACE1) and P38MAPK pathway activation.ResultsWe demonstrated that silk ligature-induced periodontitis plus injection of P. gingivalis into subgingival tissue could lead to memory and cognitive impairment. Transcriptome sequencing results suggested that there were neurodegenerative diseases in the P. gingivalis group, and the MWM test showed that periodontitis reduced the spatial learning and memory ability of mild cognitive impairment (MCI) model rats. We found high levels of inflammatory factors (TNF-α, IL-1β, IL-6, and IL-8) and CRP in the gingiva, peripheral blood and hippocampus, and the expression of APP and BACE1 was upregulated, as was the P38 MAPK pathway activation. Activated microglia and the presence of P. gingivalis were also found in the hippocampus. P38 MAPK inhibitors mitigated all of these changes.ConclusionOur findings strongly suggest that topical application of P. gingivalis increases the inflammatory burden in the peripheral and central nervous systems (CNS) and that neuroinflammation induced by activation of P38 MAPK leads to impaired learning and memory in SD rats. It can also modulate APP processing. Therefore, P38 MAPK may serve as a linking pathway between periodontitis and cognitive impairment.
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Affiliation(s)
- Ru Jin
- Chongqing Key Laboratory of Oral Disease and Biomedical Sciences and Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital, Chongqing Medical University, Chongqing, China
| | - Xiaoqiao Ning
- The First People’s Hospital of Wanzhou, Chongqing, China
| | - Xiang Liu
- Chongqing Key Laboratory of Oral Disease and Biomedical Sciences and Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital, Chongqing Medical University, Chongqing, China
| | - Yueyang Zhao
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Guo Ye
- Chongqing Key Laboratory of Oral Disease and Biomedical Sciences and Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Stomatological Hospital, Chongqing Medical University, Chongqing, China
- *Correspondence: Guo Ye,
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Zmysłowska-Polakowska E, Płoszaj T, Skoczylas S, Mojsak P, Ciborowski M, Kretowski A, Lukomska-Szymanska M, Szadkowska A, Mlynarski W, Zmysłowska A. Evaluation of the Oral Bacterial Genome and Metabolites in Patients with Wolfram Syndrome. Int J Mol Sci 2023; 24:ijms24065596. [PMID: 36982670 PMCID: PMC10053501 DOI: 10.3390/ijms24065596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/11/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023] Open
Abstract
In Wolfram syndrome (WFS), due to the loss of wolframin function, there is increased ER stress and, as a result, progressive neurodegenerative disorders, accompanied by insulin-dependent diabetes. The aim of the study was to evaluate the oral microbiome and metabolome in WFS patients compared with patients with type 1 diabetes mellitus (T1DM) and controls. The buccal and gingival samples were collected from 12 WFS patients, 29 HbA1c-matched T1DM patients (p = 0.23), and 17 healthy individuals matched by age (p = 0.09) and gender (p = 0.91). The abundance of oral microbiota components was obtained by Illumina sequencing the 16S rRNA gene, and metabolite levels were measured by gas chromatography–mass spectrometry. Streptococcus (22.2%), Veillonella (12.1%), and Haemophilus (10.8%) were the most common bacteria in the WFS patients, while comparisons between groups showed significantly higher abundance of Olsenella, Dialister, Staphylococcus, Campylobacter, and Actinomyces in the WFS group (p < 0.001). An ROC curve (AUC = 0.861) was constructed for the three metabolites that best discriminated WFS from T1DM and controls (acetic acid, benzoic acid, and lactic acid). Selected oral microorganisms and metabolites that distinguish WFS patients from T1DM patients and healthy individuals may suggest their possible role in modulating neurodegeneration and serve as potential biomarkers and indicators of future therapeutic strategies.
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Affiliation(s)
| | - T. Płoszaj
- Department of Clinical Genetics, Medical University of Lodz, 92-213 Lodz, Poland
| | - S. Skoczylas
- Department of Clinical Genetics, Medical University of Lodz, 92-213 Lodz, Poland
| | - P. Mojsak
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - M. Ciborowski
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
| | - A. Kretowski
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Bialystok, 15-276 Bialystok, Poland
| | | | - A. Szadkowska
- Department of Pediatrics, Diabetology, Endocrinology and Nephrology, Medical University of Lodz, 92-213 Lodz, Poland
| | - W. Mlynarski
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, 92-213 Lodz, Poland
| | - A. Zmysłowska
- Department of Clinical Genetics, Medical University of Lodz, 92-213 Lodz, Poland
- Correspondence: ; Tel./Fax: +48-42-272-57-67
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Prajjwal P, Asharaf S, Makhanasa D, Yamparala A, Tariq H, Aleti S, Gadam S, Vora N. Association of Alzheimer's dementia with oral bacteria, vitamin B12, folate, homocysteine levels, and insulin resistance along with its pathophysiology, genetics, imaging, and biomarkers. Dis Mon 2023; 69:101546. [PMID: 36931946 DOI: 10.1016/j.disamonth.2023.101546] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Alzheimer's disease is a prevalent form of dementia, particularly among the elderly population. It is characterized by progressive cognitive decline and neurodegeneration. Despite numerous studies, the exact cause of Alzheimer's disease remains uncertain, and various theories have been proposed, including Aβ amyloid deposition in the brain and tau protein hyper-phosphorylation. This review article explores the potential pathogenesis of Alzheimer's disease, focusing on the effects of derangements in the levels of vitamin B12, folate, and homocysteine, as well as the impact of oral bacteria causing periodontitis and insulin resistance, and their relationship to Alzheimer's. Studies have shown that high levels of homocysteine and low levels of vitamin B12 and folate, are associated with an increased risk of developing Alzheimer's disease. The article also explores the link between Alzheimer's disease and oral bacteria, specifically dental infections and periodontitis, which contribute to the inflammatory processes in the nervous system of Alzheimer's patients. There could be derangement in the insulin signaling further causing disruption in glucose metabolism within the brain, suggesting that Alzheimer's disease may represent a form of type 2 diabetes mellitus associated with the brain, commonly known as type 3 diabetes. Neuroimaging techniques, including MRI, PET, and tau PET, can identify the predictive characteristics of Alzheimer's disease, with amyloid PET being the most useful in ruling out the disease. The article concludes by stressing the importance of understanding genetic and neuroimaging factors in the diagnosing and treating Alzheimer's disease.
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Affiliation(s)
| | - Shahnaz Asharaf
- Internal Medicine, Travancore Medical College, Kollam, Kerala, India
| | | | | | - Halla Tariq
- Internal Medicine, Multan Medical and Dental College, Multan, Pakistan
| | - Soumya Aleti
- Internal Medicine, Berkshire Medical Center, Pittsfield, MA, USA
| | - Srikanth Gadam
- Internal Medicine, Postdoctoral Research Fellow, Mayo Clinic, USA
| | - Neel Vora
- Internal Medicine, B. J. Medical College, Ahmedabad, India
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Wang RPH, Huang J, Chan KWY, Leung WK, Goto T, Ho YS, Chang RCC. IL-1β and TNF-α play an important role in modulating the risk of periodontitis and Alzheimer's disease. J Neuroinflammation 2023; 20:71. [PMID: 36915108 PMCID: PMC10012546 DOI: 10.1186/s12974-023-02747-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/21/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Systemic activation of the immune system can exert detrimental effects on the central nervous system. Periodontitis, a chronic disease of the oral cavity, is a common source of systemic inflammation. Neuroinflammation might be a result of this to accelerate progressive deterioration of neuronal functions during aging or exacerbate pre-existing neurodegenerative diseases, such as Alzheimer's disease. With advancing age, the progressive increase in the body's pro-inflammatory status favors the state of vulnerability to both periodontitis and Alzheimer's disease. In the present study, we sought to delineate the roles of cytokines in the pathogenesis of both diseases. METHODS To examine the impacts of periodontitis on the onset and progression of Alzheimer's disease, 6-month-old female 3 × Tg-AD mice and their age-matched non-transgenic mice were employed. Periodontitis was induced using two different experimental models: heat-killed bacterial-induced periodontitis and ligature-induced periodontitis. To delineate the roles of pro-inflammatory cytokines in the pathogenesis of periodontitis and Alzheimer's disease, interleukin 1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) were also injected into the buccal mandibular vestibule of mice. RESULTS Here, we show that IL-1β and TNF-α were two of the most important and earliest cytokines upregulated upon periodontal infection. The systemic upregulation of these two cytokines promoted a pro-inflammatory environment in the brain contributing to the development of Alzheimer's disease-like pathology and cognitive dysfunctions. Periodontitis-induced systemic inflammation also enhanced brain inflammatory responses and subsequently exacerbated Alzheimer's disease pathology and cognitive impairment in 3 × Tg-AD mice. The role of inflammation in connecting periodontitis to Alzheimer's disease was further affirmed in the conventional magnetization transfer experiment in which increased glial responses resulting from periodontitis led to decreased magnetization transfer ratios in the brain of 3 × Tg-AD mice. CONCLUSIONS Systemic inflammation resulting from periodontitis contributed to the development of Alzheimer's disease tau pathology and subsequently led to cognitive decline in non-transgenic mice. It also potentiated Alzheimer's disease pathological features and exacerbated impairment of cognitive function in 3 × Tg-AD mice. Taken together, this study provides convincing evidence that systemic inflammation serves as a connecting link between periodontitis and Alzheimer's disease.
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Affiliation(s)
- Rachel Pei-Hsuan Wang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Laboratory Block, Rm. L4-49, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Jianpan Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Kannie Wai Yan Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong SAR, China
| | - Wai Keung Leung
- Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Tetsuya Goto
- Division of Oral Anatomy and Histology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yuen-Shan Ho
- School of Nursing, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong SAR, China
| | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Laboratory Block, Rm. L4-49, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China. .,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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Li Y, Guan X, He Y, Jia X, Pan L, Wang Y, Han Y, Zhao R, Yang J, Hou T. ProBDNF signaling is involved in periodontitis-induced depression-like behavior in mouse hippocampus. Int Immunopharmacol 2023; 116:109767. [PMID: 36738676 DOI: 10.1016/j.intimp.2023.109767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/15/2023] [Accepted: 01/19/2023] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Increasing evidence supports the association between periodontitis and depression. However, the specific mechanisms remain to be further elucidated. The present study aimed to mechanistically investigate the regional roles of proBDNF (the precursor of brain-derived neurotrophic factor) in periodontitis induced depression-like behavior in mice. METHODS Experimental periodontitis model was established by periodontal injection of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) in 8-week-old male Bdnf-HA/HA mice for 3 weeks. The depression-like behaviors, spontaneous exploratory activity and the level of anxiety were assessed by behavior tests. The activation of microglia and astrocytes, as well as the expression of Interleukin (IL)-1β and Tumor necrosis factor (TNF)-α in the hippocampus, prefrontal cortex, and cortex were further assessed by immunofluorescence and western blots. The levels of IL-1β in blood serum and expression of occludin as well as claudin5 in the hippocampus, prefrontal cortex, and cortex were further determined by enzyme-linked immunosorbent assay and western blot. Finally, the expression of proBDNF, its receptors, and mature BDNF (mBDNF), as well as neuronal activity were measured by western blots and immunofluorescence. RESULTS Pg-LPS successfully induced periodontitis in mice and caused obvious depression-like behavior. Furthermore, we observed an increased activation of astrocytes and microglia, as well as a significant increase in expression of IL-1β and TNF-α in the hippocampus of mice treated with Pg-LPS, with elevated level of IL-1β in serum and decreased expression of occludin and claudin5 in the hippocampus. Importantly, we found that the levels of proBDNF and its receptors, SorCS2 and p75NTR, were increased significantly; however, the level of mBDNF was decreased, therefor leading to greater ratio of proBDNF/mBDNF. In addition, we also detected decreased neuronal activity in the hippocampus of mice treated with Pg-LPS. CONCLUSIONS Our results indicate that Pg-LPS-induced periodontitis could cause depression-like behaviors in mice, and the proBDNF signaling is involved in the process.
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Affiliation(s)
- Yingxue Li
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Xiaoyue Guan
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yani He
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Xiangbin Jia
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Lifei Pan
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yuting Wang
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Yue Han
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Rui Zhao
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Jianmin Yang
- Department of Medicine, Weill Cornell Medical School, Cornell University, New York, NY 10065, USA.
| | - Tiezhou Hou
- Key laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Cariology and Endodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China.
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Fogelholm N, Leskelä J, Manzoor M, Holmer J, Paju S, Hiltunen K, Roitto HM, Saarela RK, Pitkälä K, Eriksdotter M, Buhlin K, Pussinen PJ, Mäntylä P. Subgingival microbiome at different levels of cognition. J Oral Microbiol 2023; 15:2178765. [PMID: 36844899 PMCID: PMC9946326 DOI: 10.1080/20002297.2023.2178765] [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] [Indexed: 02/22/2023] Open
Abstract
Oral health and declining cognition may have a bi-directional association. We characterized the subgingival microbiota composition of subjects from normal cognition to severe cognitive decline in two cohorts. Memory and Periodontitis (MINOPAR) include 202 home-living participants (50-80 years) in Sweden. Finnish Oral Health Studies in Older Adults (FINORAL) include 174 participants (≥65 years) living in long-term care in Finland. We performed oral examination and assessed the cognitive level with Mini Mental State Examination (MMSE). We sequenced the 16S-rRNA gene (V3-V4 regions) to analyse the subgingival bacterial compositions. The microbial diversities only tended to differ between the MMSE categories, and the strongest determinants were increased probing pocket depth (PPD) and presence of caries. However, abundances of 101 taxa were associated with the MMSE score. After adjusting for age, sex, medications, PPD, and caries, only eight taxa retained the significance in the meta-analyses of the two cohorts. Especially Lachnospiraceae [XIV] at the family, genus, and species level increased with decreasing MMSE. Cognitive decline is associated with obvious changes in the composition of the oral microbiota. Impaired cognition is accompanied with poor oral health status and the appearance of major taxa of the gut microbiota in the oral cavity. Good oral health-care practices require special deliberations among older adults.
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Affiliation(s)
- Nele Fogelholm
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Jaakko Leskelä
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Muhammed Manzoor
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Jacob Holmer
- Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Susanna Paju
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Kaija Hiltunen
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Hanna-Maria Roitto
- Department of Neurosciences, University of Helsinki, Helsinki, Finland.,Internal medicine and rehabilitation, Division of Geriatrics, Helsinki University Hospital Helsinki, Finland.,Population health unit, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Riitta Kt Saarela
- Department of Social Services and Health Care, Oral Health Care, Helsinki, Finland
| | - Kaisu Pitkälä
- Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland.,Unit of Primary Health Care, Helsinki University Hospital, Helsinki, Finland
| | - Maria Eriksdotter
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.,Theme Inflammation and Aging, Karolinska University Hospital, Huddinge, Sweden
| | - Kåre Buhlin
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland.,Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Pirkko J Pussinen
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland.,School of Medicine, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland
| | - Päivi Mäntylä
- School of Medicine, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland.,Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, Finland
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60
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Ximinies AD, Dou Y, Mishra A, Zhang K, Deivanayagam C, Wang C, Fletcher HM. The Oxidative Stress-Induced Hypothetical Protein PG_0686 in Porphyromonas gingivalis W83 Is a Novel Diguanylate Cyclase. Microbiol Spectr 2023; 11:e0441122. [PMID: 36719196 PMCID: PMC10101095 DOI: 10.1128/spectrum.04411-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/06/2023] [Indexed: 02/01/2023] Open
Abstract
The survival/adaptation of Porphyromonas gingivalis to the inflammatory environment of the periodontal pocket requires an ability to overcome oxidative stress. Several functional classes of genes, depending on the severity and duration of the exposure, were induced in P. gingivalis under H2O2-induced oxidative stress. The PG_0686 gene was highly upregulated under prolonged oxidative stress. PG_0686, annotated as a hypothetical protein of unknown function, is a 60 kDa protein that carries several domains including hemerythrin, PAS10, and domain of unknown function (DUF)-1858. Although PG_0686 showed some relatedness to several diguanylate cyclases (DGCs), it is missing the classical conserved, active site sequence motif (GGD[/E]EF), commonly observed in other bacteria. PG_0686-related proteins are observed in other anaerobic bacterial species. The isogenic mutant P. gingivalis FLL361 (ΔPG_0686::ermF) showed increased sensitivity to H2O2, and decreased gingipain activity compared to the parental strain. Transcriptome analysis of P. gingivalis FLL361 showed the dysregulation of several gene clusters/operons, known oxidative stress resistance genes, and transcriptional regulators, including PG_2212, CdhR and PG_1181 that were upregulated under normal anaerobic conditions. The intracellular level of c-di-GMP in P. gingivalis FLL361 was significantly decreased compared to the parental strain. The purified recombinant PG_0686 (rPG_0686) protein catalyzed the formation of c-di-GMP from GTP. Collectively, our data suggest a global regulatory property for PG_0686 that may be part of an unconventional second messenger signaling system in P. gingivalis. Moreover, it may coordinately regulate a pathway(s) vital for protection against environmental stress, and is significant in the pathogenicity of P. gingivalis and other anaerobes. IMPORTANCE Porphyromonas gingivalis is an important etiological agent in periodontitis and other systemic diseases. There is still a gap in our understanding of the mechanisms that P. gingivalis uses to survive the inflammatory microenvironment of the periodontal pocket. The hypothetical PG_0686 gene was highly upregulated under prolonged oxidative stress. Although the tertiary structure of PG_0686 showed little relatedness to previously characterized diguanylate cyclases (DGCs), and does not contain the conserved GGD(/E)EF catalytic domain motif sequence, an ability to catalyze the formation of c-di-GMP from GTP is demonstrated. The second messenger pathway for c-di-GMP was previously predicted to be absent in P. gingivalis. PG_0686 paralogs are identified in other anaerobic bacteria. Thus, PG_0686 may represent a novel class of DGCs, which is yet to be characterized. In conclusion, we have shown, for the first time, evidence for the presence of c-di-GMP signaling with environmental stress protective function in P. gingivalis.
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Affiliation(s)
- Alexia D. Ximinies
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Yuetan Dou
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Arunima Mishra
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Kangling Zhang
- Department of Pharmacology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Champion Deivanayagam
- Department of Biochemistry and Molecular Genetics, University of Alabama, Birmingham, Alabama, USA
| | - Charles Wang
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Hansel M. Fletcher
- Division of Microbiology & Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, California, USA
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61
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Martín-Hernández D, Martínez M, Robledo-Montaña J, Muñoz-López M, Virto L, Ambrosio N, Marín MJ, Montero E, Herrera D, Sanz M, Leza JC, Figuero E, García-Bueno B. Neuroinflammation related to the blood-brain barrier and sphingosine-1-phosphate in a pre-clinical model of periodontal diseases and depression in rats. J Clin Periodontol 2023; 50:642-656. [PMID: 36644813 DOI: 10.1111/jcpe.13780] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/17/2023]
Abstract
AIM To explore the potential mechanisms of neuroinflammation (microglia, blood-brain barrier [BBB] permeability, and the sphingosine-1-phosphate [S1P] pathways) resulting from the association between periodontitis and depression in rats. MATERIALS AND METHODS This pre-clinical in vivo experimental study used Wistar rats, in which experimental periodontitis (P) was induced by using oral gavages with Porphyromonas gingivalis and Fusobacterium nucleatum. Then, a chronic mild stress (CMS) model was implemented to induce a depressive-like behaviour, resulting in four groups: P with CMS (P+CMS+), P without CMS (P+CMS-), CMS without P (P-CMS+), and control (P-CMS-). After harvesting brain samples, protein/mRNA expression analyses and fluorescence immunohistochemistry were performed in the frontal cortex (FC). Results were analysed by ANOVA. RESULTS CMS exposure increased the number of microglia (an indicator of neuroinflammation) in the FC. In the combined model (P+CMS+), there was a decrease in the expression of tight junction proteins (zonula occludens-1 [ZO-1], occludin) and an increase in intercellular and vascular cell adhesion molecules (ICAM-1, VCAM-1) and matrix metalloproteinase 9 (MMP9), suggesting a more severe disruption of the BBB. The enzymes and receptors of S1P were also differentially regulated. CONCLUSIONS Microglia, BBB permeability, and S1P pathways could be relevant mechanisms explaining the association between periodontitis and depression.
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Affiliation(s)
- David Martín-Hernández
- Department of Pharmacology and Toxicology, Faculty of Medicine, Complutense University of Madrid (UCM), Hospital 12 de Octubre Research Institute (Imas12), Neurochemistry Research Institute UCM (IUIN), Madrid, Spain.,Biomedical Network Research Center of Mental Health (CIBERSAM), Institute of Health Carlos III, Madrid, Spain
| | - María Martínez
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Dental Clinical Specialties, Faculty of Dentistry, UCM, Madrid, Spain
| | - Javier Robledo-Montaña
- Department of Pharmacology and Toxicology, Faculty of Medicine, Complutense University of Madrid (UCM), Hospital 12 de Octubre Research Institute (Imas12), Neurochemistry Research Institute UCM (IUIN), Madrid, Spain.,Biomedical Network Research Center of Mental Health (CIBERSAM), Institute of Health Carlos III, Madrid, Spain
| | - Marina Muñoz-López
- Department of Pharmacology and Toxicology, Faculty of Medicine, Complutense University of Madrid (UCM), Hospital 12 de Octubre Research Institute (Imas12), Neurochemistry Research Institute UCM (IUIN), Madrid, Spain.,Biomedical Network Research Center of Mental Health (CIBERSAM), Institute of Health Carlos III, Madrid, Spain
| | - Leire Virto
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Anatomy and Embryology, Faculty of Optics, UCM, Madrid, Spain
| | - Nagore Ambrosio
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Dental Clinical Specialties, Faculty of Dentistry, UCM, Madrid, Spain
| | - Maria José Marín
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain
| | - Eduardo Montero
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Dental Clinical Specialties, Faculty of Dentistry, UCM, Madrid, Spain
| | - David Herrera
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Dental Clinical Specialties, Faculty of Dentistry, UCM, Madrid, Spain
| | - Mariano Sanz
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Dental Clinical Specialties, Faculty of Dentistry, UCM, Madrid, Spain
| | - Juan C Leza
- Department of Pharmacology and Toxicology, Faculty of Medicine, Complutense University of Madrid (UCM), Hospital 12 de Octubre Research Institute (Imas12), Neurochemistry Research Institute UCM (IUIN), Madrid, Spain.,Biomedical Network Research Center of Mental Health (CIBERSAM), Institute of Health Carlos III, Madrid, Spain
| | - Elena Figuero
- ETEP (Etiology and Therapy of Periodontal and Peri-implant Diseases) Research Group, UCM, Madrid, Spain.,Department of Dental Clinical Specialties, Faculty of Dentistry, UCM, Madrid, Spain
| | - Borja García-Bueno
- Department of Pharmacology and Toxicology, Faculty of Medicine, Complutense University of Madrid (UCM), Hospital 12 de Octubre Research Institute (Imas12), Neurochemistry Research Institute UCM (IUIN), Madrid, Spain.,Biomedical Network Research Center of Mental Health (CIBERSAM), Institute of Health Carlos III, Madrid, Spain
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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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63
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Grobler C, van Tongeren M, Gettemans J, Kell DB, Pretorius E. Alzheimer's Disease: A Systems View Provides a Unifying Explanation of Its Development. J Alzheimers Dis 2023; 91:43-70. [PMID: 36442193 DOI: 10.3233/jad-220720] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease (AD) is a debilitating neurodegenerative disorder affecting 50 million people globally. It is characterized by the presence of extracellular senile plaques and intracellular neurofibrillary tangles, consisting of amyloid-β and hyperphosphorylated tau proteins, respectively. Despite global research efforts, there is currently no cure available, due in part to an incomplete understanding of the disease pathogenesis. Numerous possible mechanisms, or hypotheses, explaining the origins of sporadic or late-onset AD have been proposed, including the amyloid-β, inflammatory, vascular, and infectious hypotheses. However, despite ample evidence, the failure of multiple trial drugs at the clinical stage illuminates the possible pitfalls of these hypotheses. Systems biology is a strategy which aims to elucidate the interactions between parts of a whole. Using this approach, the current paper shows how the four previously mentioned hypotheses of AD pathogenesis can be intricately connected. This approach allows for seemingly contradictory evidence to be unified in a system-focused explanation of sporadic AD development. Within this view, it is seen that infectious agents, such as P. gingivalis, may play a central role. The data presented here shows that when present, P. gingivalis or its virulence factors, such as gingipains, may induce or exacerbate pathologies underlying sporadic AD. This evidence supports the view that infectious agents, and specifically P. gingivalis, may be suitable treatment targets in AD.
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Affiliation(s)
- Corlia Grobler
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
| | - Marvi van Tongeren
- Department of Biomolecular Medicine, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium
| | - Jan Gettemans
- Department of Biomolecular Medicine, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium
| | - Douglas B Kell
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa.,Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.,The Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Etheresia Pretorius
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa.,Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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64
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Liu S, Dashper SG, Zhao R. Association Between Oral Bacteria and Alzheimer's Disease: A Systematic Review and Meta-Analysis. J Alzheimers Dis 2023; 91:129-150. [PMID: 36404545 DOI: 10.3233/jad-220627] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Pre-clinical evidence implicates oral bacteria in the pathogenesis of Alzheimer's disease (AD), while clinical studies show diverse results. OBJECTIVE To comprehensively assess the association between oral bacteria and AD with clinical evidence. METHODS Studies investigating the association between oral bacteria and AD were identified through a systematic search of six databases PubMed, Embase, Cochrane Central Library, Scopus, ScienceDirect, and Web of Science. Methodological quality ratings of the included studies were performed. A best evidence synthesis was employed to integrate the results. When applicable, a meta-analysis was conducted using a random-effect model. RESULTS Of the 16 studies included, ten investigated periodontal pathobionts and six were microbiome-wide association studies. Samples from the brain, serum, and oral cavity were tested. We found over a ten-fold and six-fold increased risk of AD when there were oral bacteria (OR = 10.68 95% CI: 4.48-25.43; p < 0.00001, I2 = 0%) and Porphyromonas gingivalis (OR = 6.84 95% CI: 2.70-17.31; p < 0.0001, I2 = 0%) respectively in the brain. While AD patients exhibited lower alpha diversity of oral microbiota than healthy controls, the findings of bacterial communities were inconsistent among studies. The best evidence synthesis suggested a moderate level of evidence for an overall association between oral bacteria and AD and for oral bacteria being a risk factor for AD. CONCLUSION Current evidence moderately supports the association between oral bacteria and AD, while the association was strong when oral bacteria were detectable in the brain. Further evidence is needed to clarify the interrelationship between both individual species and bacterial communities and the development of AD.
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Affiliation(s)
- Sixin Liu
- School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Stuart G Dashper
- Centre for Oral Health Research, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, Australia
| | - Rui Zhao
- Department of Stomatology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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65
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P. gingivalis-LPS Induces Mitochondrial Dysfunction Mediated by Neuroinflammation through Oxidative Stress. Int J Mol Sci 2023; 24:ijms24020950. [PMID: 36674463 PMCID: PMC9861869 DOI: 10.3390/ijms24020950] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/30/2022] [Accepted: 01/01/2023] [Indexed: 01/06/2023] Open
Abstract
Porphyromonas gingivalis (P. gingivalis), a key pathogen in periodontitis, is associated with neuroinflammation. Periodontal disease increases with age; 70.1% of adults 65 years and older have periodontal problems. However, the P. gingivalis- lipopolysaccharide (LPS)induced mitochondrial dysfunction in neurodegenerative diseases remains elusive. In this study, we investigated the possible role of P. gingivalis-LPS in mitochondrial dysfunction during neurodegeneration. We found that P. gingivalis-LPS treatment activated toll-like receptor (TLR) 4 signaling and upregulated the expression of Alzheimer's disease-related dementia and neuroinflammatory markers. Furthermore, the LPS treatment significantly exacerbated the production of reactive oxygen species and reduced the mitochondrial membrane potential. Our study highlighted the pivotal role of P. gingivalis-LPS in the repression of serum response factor (SRF) and its co-factor p49/STRAP that regulate the actin cytoskeleton. The LPS treatment repressed the genes involved in mitochondrial function and biogenesis. P. gingivalis-LPS negatively altered oxidative phosphorylation and glycolysis and reduced total adenosine triphosphate (ATP) production. Additionally, it specifically altered the mitochondrial functions in complexes I, II, and IV of the mitochondrial electron transport chain. Thus, it is conceivable that P. gingivalis-LPS causes mitochondrial dysfunction through oxidative stress and inflammatory events in neurodegenerative diseases.
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66
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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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Felsky D, Santa-Maria I, Cosacak MI, French L, Schneider JA, Bennett DA, De Jager PL, Kizil C, Tosto G. The Caribbean-Hispanic Alzheimer's disease brain transcriptome reveals ancestry-specific disease mechanisms. Neurobiol Dis 2023; 176:105938. [PMID: 36462719 PMCID: PMC10039465 DOI: 10.1016/j.nbd.2022.105938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/21/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
Identifying ancestry-specific molecular profiles of late-onset Alzheimer's Disease (LOAD) in brain tissue is crucial to understand novel mechanisms and develop effective interventions in non-European, high-risk populations. We performed gene differential expression (DE) and consensus network-based analyses in RNA-sequencing data of postmortem brain tissue from 39 Caribbean Hispanics (CH). To identify ancestry-concordant and -discordant expression profiles, we compared our results to those from two independent non-Hispanic White (NHW) samples (n = 731). In CH, we identified 2802 significant DE genes, including several LOAD known-loci. DE effects were highly concordant across ethnicities, with 373 genes transcriptome-wide significant in all three cohorts. Cross-ancestry meta-analysis found NPNT to be the top DE gene. We replicated over 82% of meta-analyses genome-wide signals in single-nucleus RNA-seq data (including NPNT and LOAD known-genes SORL1, FBXL7, CLU, ABCA7). Increasing representation in genetic studies will allow for deeper understanding of ancestry-specific mechanisms and improving precision treatment options in understudied groups.
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Affiliation(s)
- Daniel Felsky
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, 250 College St., M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada; Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Ismael Santa-Maria
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Mehmet Ilyas Cosacak
- German Center for Neurodegenerative Diseases (DZNE) Dresden, Helmholtz Association, Tatzberg 41, 01307 Dresden, Germany
| | - Leon French
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, 250 College St., M5T 1R8, Canada; Department of Psychiatry, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Julie A Schneider
- Department of Neurology, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA; Rush Alzheimer's Disease Center, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA
| | - David A Bennett
- Department of Neurology, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA; Rush Alzheimer's Disease Center, Rush University Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA
| | - Philip L De Jager
- Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA; The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Caghan Kizil
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA; German Center for Neurodegenerative Diseases (DZNE) Dresden, Helmholtz Association, Tatzberg 41, 01307 Dresden, Germany; The Department of Neurology, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA
| | - Giuseppe Tosto
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA; The Department of Neurology, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA; Gertrude H. Sergievsky Centre, Columbia University Medical Center, 630 West 168th St., New York, NY 10032, USA.
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68
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de Jongh CA, de Vries TJ, Bikker FJ, Gibbs S, Krom BP. Mechanisms of Porphyromonas gingivalis to translocate over the oral mucosa and other tissue barriers. J Oral Microbiol 2023; 15:2205291. [PMID: 37124549 PMCID: PMC10134951 DOI: 10.1080/20002297.2023.2205291] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Introduction The oral pathogen Porphyromonas gingivalis is not only associated with periodontitis but also with systemic diseases elsewhere in the body. The mechanisms by which P. gingivalis travels from the oral cavity to other organs in the body are largely unknown. This review describes the four putative mechanisms supported by experimental evidence, which enable translocation of P. gingivalis over the oral mucosa, endothelial barriers and subsequent dissemination into the bloodstream. Mechanisms The first mechanism: proteolytic enzymes secreted by P. gingivalis degrade adhesion molecules between tissue cells, and the extracellular matrix. This weakens the structural integrity of the mucosa and allows P. gingivalis to penetrate the tissue. The second is transcytosis: bacteria actively enter tissue cells and transfer to the next layer or the extracellular space. By travelling from cell to cell, P. gingivalis reaches deeper structures. Thirdly, professional phagocytes take up P. gingivalis and travel to the bloodstream where P. gingivalis is released. Lastly, P. gingivalis can adhere to the hyphae forming Candida albicans. These hyphae can penetrate the mucosal tissue, which may allow P. gingivalis to reach deeper structures. Conclusion More research could elucidate targets to inhibit P. gingivalis dissemination and prevent the onset of various systemic diseases.
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Affiliation(s)
- Caroline A. de Jongh
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Department of Periodontology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Teun J. de Vries
- Department of Periodontology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Floris J. Bikker
- Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Susan Gibbs
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Bastiaan P. Krom
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
- CONTACT Bastiaan P. Krom Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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Matsumoto H, Tagai K, Endo H, Matsuoka K, Takado Y, Kokubo N, Shimada H, Goto T, Goto TK, Higuchi M. Association of Tooth Loss with Alzheimer's Disease Tau Pathologies Assessed by Positron Emission Tomography. J Alzheimers Dis 2023; 96:1253-1265. [PMID: 37980663 PMCID: PMC10741329 DOI: 10.3233/jad-230581] [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] [Accepted: 09/24/2023] [Indexed: 11/21/2023]
Abstract
BACKGROUND Deterioration of the oral environment is one of the risk factors for dementia. A previous study of an Alzheimer's disease (AD) model mouse suggests that tooth loss induces denervation of the mesencephalic trigeminal nucleus and neuroinflammation, possibly leading to accelerated tau dissemination from the nearby locus coeruleus (LC). OBJECTIVE To elucidate the relevance of oral conditions and amyloid-β (Aβ) and tau pathologies in human participants. METHODS We examined the number of remaining teeth and the biofilm-gingival interface index in 24 AD-spectrum patients and 19 age-matched healthy controls (HCs). They also underwent positron emission tomography (PET) imaging of Aβ and tau with specific radiotracers, 11C-PiB and 18F-PM-PBB3, respectively. All AD-spectrum patients were Aβ-positive, and all HCs were Aβ-negative. We analyzed the correlation between the oral parameters and radiotracer retention. RESULTS No differences were found in oral conditions between the AD and HC groups. 11C-PiB retentions did not correlate with the oral indices in either group. In AD-spectrum patients, brain-wide, voxel-based image analysis highlighted several regions, including the LC and associated brainstem substructures, as areas where 18F-PM-PBB3 retentions negatively correlated with the remaining teeth and revealed the correlation of tau deposits in the LC (r = -0.479, p = 0.018) primarily with the hippocampal and neighboring areas. The tau deposition in none of the brain regions was associated with the periodontal status. CONCLUSIONS Our findings with previous preclinical evidence imply that tooth loss may enhance AD tau pathogenesis, promoting tau spreading from LC to the hippocampal formation.
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Affiliation(s)
- Hideki Matsumoto
- Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Kenji Tagai
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Psychiatry, The Jikei University of Medicine, Tokyo, Japan
| | - Hironobu Endo
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Kiwamu Matsuoka
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Yuhei Takado
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Naomi Kokubo
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
| | - Hitoshi Shimada
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Department of Functional Neurology & Neurosurgery, Center for Integrated Human Brain Science, Brain Research Institute, Niigata University, Niigata, Japan
| | - Tetsuya Goto
- Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tazuko K. Goto
- Department of Oral and Maxillofacial Radiology, Tokyo Dental College, Tokyo, Japan
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
- Tokyo Dental College Research Branding Project, Tokyo Dental College, Tokyo, Japan
- Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Makoto Higuchi
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
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Kanagasingam S, von Ruhland C, Welbury R, Singhrao SK. Ex vivo Detection of Amyloid-β in Naturally Formed Oral Biofilm. J Alzheimers Dis Rep 2022; 6:757-773. [PMID: 36721488 PMCID: PMC9837734 DOI: 10.3233/adr-220076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/18/2022] [Indexed: 12/12/2022] Open
Abstract
Background Oral infection has been implicated in the possible etiology of Alzheimer's disease. Objective To detect amyloid-β (Aβ) within microbial biofilms. Methods Freshly extracted teeth (N = 87) with periodontal disease were separated into Group A (N = 11), with primary root canal infection and Group B (N = 21) with failed endodontic treatment identified by the presence of, gutta percha root filling. Biofilm characteristics were observed by scanning electron microscopy (SEM). Demineralized paraffin wax embedded tooth sections and mineralized calculus biofilm were immunostained with the anti-Aβ antibody. The gutta perchas were processed either for on-section acrylic resin tissue immunocolloidal gold silver staining (IGSS) using the anti-Aβ antibody or in Araldite resin for ultrastructure. Results SEM demonstrated calculus and gutta percha in situ harboring a polymicrobial biofilm featuring extracellular polymeric substance (EPS) and water channels. Immunohistochemistry on rehydrated paraffin wax tooth sections from Group A, demonstrated Aβ staining on external (calculus and plaque) and all intracanal infected regions. In Group B, the gutta percha biofilm IGSS gave an inconclusive result for Aβ. Transmission electron microscopy of selected teeth with infected intra-canals (Group A) and 20% of gutta percha biofilm (Group B) EPS contained electron dense fibrils of variable sizes, some of which were typical of human Aβ fibrils. Conclusion This study detected both soluble and insoluble Aβ fibrils within the EPS of periodontal and endodontic natural biofilm, strongly suggesting its role as an antimicrobial peptide in combatting local infection, with potential risk for cross-seeding into the brain for AD development.
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Affiliation(s)
- Shalini Kanagasingam
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Christopher von Ruhland
- Electron and Light Microscopy Facility, College of Biomedical and Life Sciences, Cardiff University, Wales, UK
| | - Richard Welbury
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Sim K. Singhrao
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK,Correspondence to: Sim K. Singhrao, University of Central Lancashire, Preston, PR1 2HE, UK. E-mail:
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Li C, Yu R, Ding Y. Association between Porphyromonas Gingivalis and systemic diseases: Focus on T cells-mediated adaptive immunity. Front Cell Infect Microbiol 2022; 12:1026457. [PMID: 36467726 PMCID: PMC9712990 DOI: 10.3389/fcimb.2022.1026457] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/25/2022] [Indexed: 12/01/2023] Open
Abstract
The association between periodontal disease and systemic disease has become a research hotspot. Porphyromonas gingivalis (P. gingivalis), a crucial periodontal pathogen, affects the development of systemic diseases. The pathogenicity of P. gingivalis is largely linked to interference with the host's immunity. This review aims to discover the role of P. gingivalis in the modulation of the host's adaptive immune system through a large number of virulence factors and the manipulation of cellular immunological responses (mainly mediated by T cells). These factors may affect the cause of large numbers of systemic diseases, such as atherosclerosis, hypertension, adverse pregnancy outcomes, inflammatory bowel disease, diabetes mellitus, non-alcoholic fatty liver disease, rheumatoid arthritis, and Alzheimer's disease. The point of view of adaptive immunity may provide a new idea for treating periodontitis and related systemic diseases.
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Affiliation(s)
- Cheng Li
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- School of Stomatology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, China
| | - Ran Yu
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- School of Stomatology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, China
| | - Yumei Ding
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- School of Stomatology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, China
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Li X, Kiprowska M, Kansara T, Kansara P, Li P. Neuroinflammation: A Distal Consequence of Periodontitis. J Dent Res 2022; 101:1441-1449. [PMID: 35708472 PMCID: PMC9608094 DOI: 10.1177/00220345221102084] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Periodontitis, a chronic, inflammatory disease, induces systemic inflammation and contributes to the development of neurodegenerative diseases. The precise etiology of the most common neurodegenerative disorders, such as sporadic Alzheimer's, Parkinson's diseases and multiple sclerosis (AD, PD, and MS, respectively), remains to be revealed. Chronic neuroinflammation is a well-recognized component of these disorders, and evidence suggests that systemic inflammation is a possible stimulus for neuroinflammation development. Systemic inflammation can lead to deleterious consequences on the brain if the inflammation is sufficiently severe or if the brain shows vulnerabilities due to genetic predisposition, aging, or neurodegenerative diseases. It has been proposed that periodontal disease can initiate or contribute to the AD pathogenesis through multiple pathways, including key periodontal pathogens. Dysbiotic oral bacteria can release bacterial products into the bloodstream and eventually cross the brain-blood barrier; these bacteria can also cause alterations to gut microbiota that enhance inflammation and potentially affect brain function via the gut-brain axis. The trigeminal nerve has been suggested as another route for connecting oral bacterial products to the brain. PD and MS are often preceded by gastrointestinal symptoms or aberrant gut microbiome composition, and alterations in the enteric nervous system accompany the disease. Clinical evidence has suggested that patients with periodontitis are at a higher risk of developing PD and MS. This nexus among the brain, periodontal disease, and systemic inflammation heralds new ways in which microglial cells, the main innate immune cells, and astrocytes, the crucial regulators of innate and adaptive immune responses in the brain, contribute to brain pathology. Currently, the lack of understanding of the pathogenesis of neurodegeneration is hindering treatment development. However, we may prevent this pathogenesis by tackling one of its possible contributors (periodontitis) for systemic inflammation through simple preventive oral hygiene measures.
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Affiliation(s)
- X. Li
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
- Department of Urology, New York University Grossman School of Medicine, New York, NY, USA
- Perlmutter Cancer Institute, New York University Langone Medical Center, New York, NY, USA
| | - M. Kiprowska
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
| | - T. Kansara
- Cleveland Clinic- Union hospital, Dover, OH, USA
| | - P. Kansara
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
| | - P. Li
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, USA
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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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Kanagasingam S, von Ruhland C, Welbury R, Chukkapalli SS, Singhrao SK. Porphyromonas gingivalis Conditioned Medium Induces Amyloidogenic Processing of the Amyloid-β Protein Precursor upon in vitro Infection of SH-SY5Y Cells. J Alzheimers Dis Rep 2022; 6:577-587. [PMID: 36275415 PMCID: PMC9535609 DOI: 10.3233/adr-220029] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/23/2022] [Indexed: 12/27/2022] Open
Abstract
Background: Cleavage of the amyloid-β protein precursor (AβPP) mediated by host secretase enzymes, releases several fragments including amyloid-β (Aβ40 and Aβ42). Objective: To determine if Porphyromonas gingivalis conditioned medium cleaved AβPP to release Aβ40 and Aβ42. Methods: The SH-SY5Y cell line was challenged, in vitro, with P. gingivalis (Pg381) conditioned medium in the presence/absence of cytokines. The cells and their supernatants were assessed for AβPP cleavage fragments by immunoblotting and transmission electron microscopy. Results: Western blotting of the cell lysates with the anti-AβPP C-terminal antibody demonstrated variable molecular weight bands corresponding to full length and fragmented AβPP in lanes treated with the following factors: Tryptic soy broth (TSB), Pg381, IL-6, Pg381 + IL-1β, and Pg381 + TNF-α. The low molecular weight bands corresponding to the C99 dimerized fragment were observed in the Pg381 and interlukin-6 (IL-6) treated groups and were significantly more intense in the presence of Pg381 with either IL-6 or TNF-α. Bands corresponding to the dimerized C83 fragment were observed with cells treated with TNF-α alone and with Pg381 combined with IL-1β or IL-6 or TNF-α. The anti-Aβ antibody detected statistically significant Aβ40 and Aβ42, levels when these two Aβ species were pooled across test samples and compared to the untreated group. Electron microscopic examination of the supernatants demonstrated insoluble Aβ40 and Aβ42. Conclusion: These observations strongly imply that AβPP is an infection responsive protein cleaved via the amyloidogenic pathway on exposure to conditioned medium and in the presence of pro-inflammatory mediators.
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Affiliation(s)
- Shalini Kanagasingam
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Christopher von Ruhland
- Electron and Light Microscopy Facility, College of Biomedical and Life Sciences, Cardiff University, Wales, UK
| | - Richard Welbury
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | | | - Sim K. Singhrao
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
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Yan C, Diao Q, Zhao Y, Zhang C, He X, Huang R, Li Y. Fusobacterium nucleatum infection-induced neurodegeneration and abnormal gut microbiota composition in Alzheimer’s disease-like rats. Front Neurosci 2022; 16:884543. [PMID: 36188448 PMCID: PMC9523129 DOI: 10.3389/fnins.2022.884543] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
Objective To explore whether Fusobacterium nucleatum could lead to behavioral and pathological changes in Alzheimer’s disease (AD)-like model rat and whether they could affect the gut microbiota. Methods The cognitive ability and alveolar bone loss of Sprague-Dawley (SD) rats were tested by Morris water maze and Micro-CT, respectively. HE staining and immunohistochemistry were used to analyze the pathological changes and Aβ1–42 in brains. Western blot was applied to detect the expression of p-Tau 181 in the brain. Limulus amebocyte lysate assay and PCR were performed to determine serum LPS level and whether F. nucleatum accessed the brain, respectively. The gut microbiota was analyzed by the 16S rRNA gene sequence. Results Oral infection with F. nucleatum could induce increased alveolar bone loss and learning impairment in AD-like rats. Additionally, F. nucleatum exposure increased the Aβ1–42 expression by about one-fourth (P < 0.05), p-Tau181 by about one-third (P < 0.05), and serum LPS (P < 0.05) in AD-like rats. Moreover, F. nucleatum could change the gut microflora composition in AD-like rats, accompanied by a significant increase in the abundance of Streptococcus and Prevotella. Conclusion Oral infection with F. nucleatum could contribute to abnormalities in cognitive ability and pathological change in the brain of AD-like rats, which may be related to abnormal gut microbiota composition.
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Affiliation(s)
- Caixia Yan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Qilin Diao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Yuxi Zhao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Cheng Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Xiaoya He
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Ruijie Huang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
- Department of Pediatric Dentistry, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Yan Li
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
- *Correspondence: Yan Li,
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Kanagasingam S, von Ruhland C, Welbury R, Singhrao SK. Antimicrobial, Polarizing Light, and Paired Helical Filament Properties of Fragmented Tau Peptides of Selected Putative Gingipains. J Alzheimers Dis 2022; 89:1279-1291. [PMID: 36031895 DOI: 10.3233/jad-220486] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Tau is an established substrate for gingipains secreted by Porphyromonas gingivalis. Hyperphosphorylation of tau and neurofibrillary tangle (NFT) formation is a defining lesion of Alzheimer's disease (AD) where NFT distribution is related to Braak stage and disease severity. OBJECTIVE To assess gingipains'-fragmented tau peptides for their antimicrobial properties and for the likelihood of paired helical/straight filament (PHF/SF) formation with implications for the NFT lesion. METHODS Seven non-phosphorylated (A-G) and three phosphorylated (A-C) tau peptides, were tested for antimicrobial properties against P. gingivalis. Polarizing light properties were determined using Congo Red staining. Secondary and tertiary structures of peptides B-F were determined using transmission electron microscopy (TEM) and circular dichroism (CD) was undertaken for the soluble peptides A in phosphorylated and non-phosphorylated states. RESULTS Phosphorylated tau peptide A displayed a significant effect against planktonic P. gingivalis. The CD results demonstrated that both peptides A, in phosphorylated and non-phosphorylated states, in aqueous solution, adopted mainly β-type structures. Non-phosphorylated peptides B-F and phosphorylated peptides B-C were insoluble and fibrillar under the TEM. The secondary and tertiary structures of the non-phosphorylated peptide B demonstrated fewer helical twists, whereas peptide C displayed significantly more helical twists along the whole fiber(s) length following its phosphorylation. CONCLUSION Phosphorylated peptide A reduced P. gingivalis viability. CD spectroscopy demonstrated the phosphorylated and the non-phosphorylated peptide A predominantly formed from β-sheet structures in aqueous solution with potential antimicrobial activity. Phosphorylation of tau peptides physically changed their tertiary structure into PHFs with potential for self-aggregation and binding to the NFT lesion.
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Affiliation(s)
- Shalini Kanagasingam
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Christopher von Ruhland
- Electron and Light Microscopy Facility, College of Biomedical and Life Sciences, Cardiff University, Wales, UK
| | - Richard Welbury
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Sim K Singhrao
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
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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: 32] [Impact Index Per Article: 16.0] [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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Giordano-Kelhoffer B, Lorca C, March Llanes J, Rábano A, del Ser T, Serra A, Gallart-Palau X. Oral Microbiota, Its Equilibrium and Implications in the Pathophysiology of Human Diseases: A Systematic Review. Biomedicines 2022; 10:biomedicines10081803. [PMID: 36009350 PMCID: PMC9405223 DOI: 10.3390/biomedicines10081803] [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: 05/31/2022] [Revised: 07/19/2022] [Accepted: 07/23/2022] [Indexed: 02/06/2023] Open
Abstract
Imbalances of the oral microbiota and dysbiosis have traditionally been linked to the occurrence of teeth and oral diseases. However, recent findings indicate that this microbiota exerts relevant influence in systemic health. Dysbiosis of the oral microbiota is implicated in the apparition and progression of cardiovascular, neurodegenerative and other major human diseases. In fact, the oral microbiota are the second most diverse and largely populated microbiota of the human body and its relationships with systemic health, although widely explored, they still lack of proper integration. The purpose of this systematic review is thus to widely examine the implications of oral microbiota in oral, cardiovascular and neurodegenerative diseases to offer integrative and up-to-date interpretations. To achieve that aim, we identified a total of 121 studies curated in PUBMED from the time interval January 2003–April 2022, which after careful screening resulted in 79 studies included. The reviewed scientific literature provides plausible vias of implication of dysbiotic oral microbiota in systemic human diseases, and encourages further research to continue elucidating the highly relevant and still poorly understood implications of this niche microbiota in systemic health. PROSPERO Registration Number: CRD42022299692. This systematic review follows relevant PRISMA guidelines.
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Affiliation(s)
- Barbara Giordano-Kelhoffer
- Faculty of Dentistry, Universitat Internacional de Catalunya (UIC), 08017 Barcelona, Spain;
- Bioengineering Institute of Technology, Faculty of Health Sciences, Universitat Internacional de Catalunya (UIC), 08017 Barcelona, Spain
- Faculty of Health Sciences, Valencian International University, 46002 Valencia, Spain
- Biomedical Research Institute of Lleida Dr. Pifarré Foundation (IRB Lleida), Neuroscience Area, +Pec Proteomics Research Group (+PPRG), University Hospital Arnau de Vilanova (HUAV), 25198 Lleida, Spain;
| | - Cristina Lorca
- Biomedical Research Institute of Lleida Dr. Pifarré Foundation (IRB Lleida), Neuroscience Area, +Pec Proteomics Research Group (+PPRG), University Hospital Arnau de Vilanova (HUAV), 25198 Lleida, Spain;
- IMDEA—Food Research Institute, +Pec Proteomics, Campus of International Excellence UAM + CSIC, Old Cantoblanco Hospital, 8 Crta. Canto Blanco, 28049 Madrid, Spain
| | - Jaume March Llanes
- NeuroPGA Research Group—Psychology Department, University of Lleida (UdL), 25001 Lleida, Spain;
| | - Alberto Rábano
- Alzheimer’s Centre Reina Sofia—CIEN Foundation, 28031 Madrid, Spain; (A.R.); (T.d.S.)
| | - Teodoro del Ser
- Alzheimer’s Centre Reina Sofia—CIEN Foundation, 28031 Madrid, Spain; (A.R.); (T.d.S.)
| | - Aida Serra
- IMDEA—Food Research Institute, +Pec Proteomics, Campus of International Excellence UAM + CSIC, Old Cantoblanco Hospital, 8 Crta. Canto Blanco, 28049 Madrid, Spain
- Correspondence: (A.S.); (X.G.-P.); Tel.: +34-91-7278-100 (A.S.); +34-97-3702-224 (X.G.-P.)
| | - Xavier Gallart-Palau
- Faculty of Health Sciences, Valencian International University, 46002 Valencia, Spain
- Biomedical Research Institute of Lleida Dr. Pifarré Foundation (IRB Lleida), Neuroscience Area, +Pec Proteomics Research Group (+PPRG), University Hospital Arnau de Vilanova (HUAV), 25198 Lleida, Spain;
- Psychology Department, University of Lleida (UdL), 25001 Lleida, Spain
- Correspondence: (A.S.); (X.G.-P.); Tel.: +34-91-7278-100 (A.S.); +34-97-3702-224 (X.G.-P.)
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80
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Nolde M, Holtfreter B, Kocher T, Alayash Z, Reckelkamm SL, Ehmke B, Baurecht H, Baumeister SE. No bidirectional relationship between depression and periodontitis: A genetic correlation and Mendelian randomization study. Front Immunol 2022; 13:918404. [PMID: 35935963 PMCID: PMC9355660 DOI: 10.3389/fimmu.2022.918404] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/27/2022] [Indexed: 11/15/2022] Open
Abstract
Background Observational and in-vivo research suggested a bidirectional relationship between depression and periodontitis. We estimated the genetic correlation and examined directionality of causation. Methods The study used summary statistics from published genome wide association studies, with sample sizes ranging from 45,563 to 797,563 individuals of European ancestry. We performed linkage disequilibrium score regression (LDSC) to estimate global correlation and used Heritability Estimation from Summary Statistics (ρ-HESS) to further examine local genetic correlation. Latent Heritable Confounder Mendelian randomization (LHC-MR), Causal Analysis using Summary Effect estimates (CAUSE), and conventional MR approaches assessed bidirectional causation. Results LDSC observed only weak genetic correlation (rg = 0.06, P-Value = 0.619) between depression and periodontitis. Analysis of local genetic correlation using ρ-HESS did not reveal loci of significant local genetic covariance. LHC-MR, CAUSE and conventional MR models provided no support for bidirectional causation between depression and periodontitis, with odds ratios ranging from 1.00 to 1.06 in either direction. Conclusions Results do not support shared heritability or a causal connection between depression and periodontitis.
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Affiliation(s)
- Michael Nolde
- Institute of Health Services Research in Dentistry, University of Münster, Münster, Germany
- *Correspondence: Michael Nolde,
| | - Birte Holtfreter
- Department of Restorative Dentistry, Periodontology, Endodontology, and Preventive and Pediatric Dentistry, University Medicine Greifswald, Greifswald, Germany
| | - Thomas Kocher
- Department of Restorative Dentistry, Periodontology, Endodontology, and Preventive and Pediatric Dentistry, University Medicine Greifswald, Greifswald, Germany
| | - Zoheir Alayash
- Institute of Health Services Research in Dentistry, University of Münster, Münster, Germany
| | - Stefan Lars Reckelkamm
- Institute of Health Services Research in Dentistry, University of Münster, Münster, Germany
| | - Benjamin Ehmke
- Clinic for Periodontology and Conservative Dentistry, University of Münster, Münster, Germany
| | - Hansjörg Baurecht
- Department of Epidemiology and Preventive Medicine, University of Regensburg, Regensburg, Germany
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Karakaya E, Abdul Y, Chowdhury N, Wellslager B, Jamil S, Albayram O, Yilmaz Ö, Ergul A. Porphyromonas gingivalis infection upregulates the endothelin (ET) system in brain microvascular endothelial cells. Can J Physiol Pharmacol 2022; 100:679-688. [PMID: 35442801 PMCID: PMC9583200 DOI: 10.1139/cjpp-2022-0035] [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] [Indexed: 11/22/2022]
Abstract
Endothelin-1 (ET-1), the most potent vasoconstrictor identified to date, contributes to cerebrovascular dysfunction and brain ET-1 levels were shown to be related to Alzheimer's disease and related dementias (ADRD) progression. ET-1 also contributes to neuroinflammation, especially in infections of the central nervous system. Recent studies causally linked chronic periodontal infection with an opportunistic anaerobic bacterium Porphyromonas gingivalis (Coykendall et al.) Shah & Collins to AD development. Thus, the goal of the study was to determine the impact of P. gingivalis infection on the ET system and cell senescence in brain microvascular endothelial cells. Cells were infected with a multiplicity of infection 50 P. gingivalis with and without extracellular ATP-induced oxidative stress for 24 h. Cell lysates were collected for analysis of endothelin A receptor (ETA)/endothelin B receptor (ETB) receptor as well as senescence markers. ET-1 levels in cell culture media were measured with enzyme-linked immunosorbent assay. P. gingivalis infection increased ET-1 (pg/mL) secretion, as well as the ETA receptor expression, whereas decreased lamin A/C expression compared to control. Tight junction protein claudin-5 was also decreased under these conditions. ETA or ETB receptor blockade during infection did not affect ET-1 secretion or the expression of cell senescence markers. Current findings suggest that P. gingivalis infection may compromise endothelial integrity and activate the ET system.
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Affiliation(s)
- Eda Karakaya
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina
- Department of Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC
| | - Yasir Abdul
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina
- Department of Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC
| | | | | | - Sarah Jamil
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina
- Department of Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC
| | - Onder Albayram
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina
- Department of Neurosciences, Medical University of South Carolina
| | - Özlem Yilmaz
- Department of Oral Health Sciences, Medical University of South Carolina
| | - Adviye Ergul
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina
- Department of Neurosciences, Medical University of South Carolina
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82
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Wu H, Qiu W, Zhu X, Li X, Xie Z, Carreras I, Dedeoglu A, Van Dyke T, Han YW, Karimbux N, Tu Q, Cheng L, Chen J. The Periodontal Pathogen Fusobacterium nucleatum Exacerbates Alzheimer's Pathogenesis via Specific Pathways. Front Aging Neurosci 2022; 14:912709. [PMID: 35813949 PMCID: PMC9260256 DOI: 10.3389/fnagi.2022.912709] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/07/2022] [Indexed: 01/21/2023] Open
Abstract
Alzheimer's Disease (AD) is the most common form of dementia in older adults and has a devastating impact on the patient's quality of life, which creates a significant socio-economic burden for the affected individuals and their families. In recent years, studies have identified a relationship between periodontitis and AD. Periodontitis is an infectious/inflammatory disease that destroys the supporting periodontal structure leading to tooth loss. Dysbiosis of the oral microbiome plays a significant role in the onset and development of periodontitis exhibiting a shift to overgrowth of pathobionts in the normal microflora with increasing local inflammation. Fusobacterium nucleatum is a common pathogen that significantly overgrows in periodontitis and has also been linked to various systemic diseases. Earlier studies have reported that antibodies to F. nucleatum can be detected in the serum of patients with AD or cognitive impairment, but a causal relationship and a plausible mechanism linking the two diseases have not been identified. In this study, we conducted both in vivo and in vitro experiments and found that F. nucleatum activates microglial cells causing morphological changes, accelerated proliferation and enhanced expression of TNF-α and IL-1β in microglial cells. In our in vivo experiments, we found that F. nucleatum-induced periodontitis resulted in the exacerbation of Alzheimer's symptoms in 5XFAD mice including increased cognitive impairment, beta-amyloid accumulation and Tau protein phosphorylation in the mouse cerebrum. This study may suggest a possible link between a periodontal pathogen and AD and F. nucleatum could be a risk factor in the pathogenesis of AD. We are currently further identifying the pathways through which F. nucleatum modulates molecular elements in enhancing AD symptoms and signs. Data are available via ProteomeXchange with identifier PXD033147.
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Affiliation(s)
- Hongle Wu
- Department of Endodontics, Stomatological Hospital, Southern Medical University, Guangzhou, China,State Key Laboratory of Oral Disease, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China,Division of Oral Biology, Tufts University School of Dental Medicine, Boston, MA, United States
| | - Wei Qiu
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaofang Zhu
- Division of Oral Biology, Tufts University School of Dental Medicine, Boston, MA, United States,Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA, United States
| | - Xiangfen Li
- State Key Laboratory of Oral Disease, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China
| | - Zhongcong Xie
- Geriatric Anesthesia Research Unit, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States
| | - Isabel Carreras
- Department of Veterans Affairs, VA Boston Healthcare System, Boston, MA, United States,Department of Neurology and Department of Biochemistry School of Medicine, Boston University, Boston, MA, United States
| | - Alpaslan Dedeoglu
- Department of Veterans Affairs, VA Boston Healthcare System, Boston, MA, United States,Department of Neurology School of Medicine, Boston University, Boston, MA, United States
| | - Thomas Van Dyke
- The Forsyth Institute, Clinical and Translational Research, Cambridge, MA, United States,Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
| | - Yiping W. Han
- Section of Oral, Diagnostic and Rehabilitation Sciences, College of Dental Medicine, University Irvign Medical Center, New York, NY, United States,Department of Microbiology & Immunology, Vagelos College of Physicians & Surgeons, Columbia University Irvign Medical Center, New York, NY, United States
| | - Nadeem Karimbux
- Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA, United States
| | - Qisheng Tu
- Division of Oral Biology, Tufts University School of Dental Medicine, Boston, MA, United States,Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA, United States
| | - Lei Cheng
- State Key Laboratory of Oral Disease, West China Hospital of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China,*Correspondence: Lei Cheng,
| | - Jake Chen
- Division of Oral Biology, Tufts University School of Dental Medicine, Boston, MA, United States,Department of Periodontology, Tufts University School of Dental Medicine, Boston, MA, United States,Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA, United States,Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States,Jake Chen,
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83
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Zhou X, Afzal S, Wohlmuth H, Münch G, Leach D, Low M, Li CG. Synergistic Anti-Inflammatory Activity of Ginger and Turmeric Extracts in Inhibiting Lipopolysaccharide and Interferon-γ-Induced Proinflammatory Mediators. Molecules 2022; 27:3877. [PMID: 35745000 PMCID: PMC9229778 DOI: 10.3390/molecules27123877] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 12/15/2022] Open
Abstract
This study aims to investigate the combined anti-inflammatory activity of ginger and turmeric extracts. By comparing the activities of individual and combined extracts in lipopolysaccharide and interferon-γ-induced murine RAW 264.7 cells, we demonstrated that ginger-turmeric combination was optimal at a specific ratio (5:2, w/w) in inhibiting nitric oxide, tumour necrosis factor and interleukin 6 with synergistic interaction (combination index < 1). The synergistic inhibitory effect on TNF was confirmed in human monocyte THP-1 cells. Ginger-turmeric combination (5:2, w/w) also upregulated nuclear factor erythroid 2−related factor 2 activity and heme oxygenase-1 protein expression. Additionally, 6-shogaol, 8-shogaol, 10-shogaol and curcumin were the leading compounds in reducing major proinflammatory mediators and cytokines, and a simplified compound combination of 6-s, 10-s and curcumin showed the greatest potency in reducing LPS-induced NO production. Our study provides scientific evidence in support of the combined use of ginger and turmeric to alleviate inflammatory processes.
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Affiliation(s)
- Xian Zhou
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (H.W.); (M.L.)
| | - Sualiha Afzal
- Pharmacology Unit, School of Medicine, Western Sydney University, Narellan Road & Gilchrist Drive, Campbelltown, NSW 2560, Australia; (S.A.); (G.M.)
| | - Hans Wohlmuth
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (H.W.); (M.L.)
- Integria Healthcare, 2728 Logan Road, Brisbane, QLD 4113, Australia;
- School of Chemistry & Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Gerald Münch
- Pharmacology Unit, School of Medicine, Western Sydney University, Narellan Road & Gilchrist Drive, Campbelltown, NSW 2560, Australia; (S.A.); (G.M.)
| | - David Leach
- Integria Healthcare, 2728 Logan Road, Brisbane, QLD 4113, Australia;
| | - Mitchell Low
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (H.W.); (M.L.)
| | - Chun Guang Li
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (H.W.); (M.L.)
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84
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Abstract
The potential contribution of pathogenic microbes to dementia-inducing disease is a subject of considerable importance. Alzheimer’s disease (AD) is a neurocognitive disease that slowly destroys brain function, leading to cognitive decline and behavioral and psychiatric disorders. The histopathology of AD is associated with neuronal loss and progressive synaptic dysfunction, accompanied by the deposition of amyloid-β (Aβ) peptide in the form of parenchymal plaques and abnormal aggregated tau protein in the form of neurofibrillary tangles. Observational, epidemiological, experimental, and pathological studies have generated evidence for the complexity and possible polymicrobial causality in dementia-inducing diseases. The AD pathogen hypothesis states that pathogens and microbes act as triggers, interacting with genetic factors to initiate the accumulation of Aβ, hyperphosphorylated tau protein (p-tau), and inflammation in the brain. Evidence indicates that Borrelia sp., HSV-1, VZV (HHV-2), HHV-6/7, oral pathogens, Chlamydophila pneumoniae, and Candida albicans can infect the central nervous system (CNS), evade the immune system, and consequently prevail in the AD brain. Researchers have made significant progress in understanding the multifactorial and overlapping factors that are thought to take part in the etiopathogenesis of dementia; however, the cause of AD remains unclear.
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85
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Zhao J, Zhao D, Wang J, Luo X, Guo R. Inflammation—Cause or consequence of late onset Alzheimer’s disease or both? A review of the evidence. EUR J INFLAMM 2022. [DOI: 10.1177/1721727x221095383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Accumulating evidence suggests that inflammation is involved in the development of late onset Alzheimer’s disease (LOAD). However, it is not clear whether inflammation is a cause or consequence, or both. The aim of this paper is to review the relationship between inflammation and LOAD. We also review the effect of anti-inflammation on the risk of LOAD to further elucidate the relationship between inflammation and LOAD.
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Affiliation(s)
- Jinrong Zhao
- Academy of Life Science, School of Medicine, Xi’an International University, Xi’an, China
- Engineering Research Center of Personalized Anti-aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an, China
| | - Dong Zhao
- Academy of Life Science, School of Medicine, Xi’an International University, Xi’an, China
- Engineering Research Center of Personalized Anti-aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an, China
| | - Jinpei Wang
- Academy of Life Science, School of Medicine, Xi’an International University, Xi’an, China
- Engineering Research Center of Personalized Anti-aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an, China
| | - Xiaoe Luo
- Academy of Life Science, School of Medicine, Xi’an International University, Xi’an, China
- Engineering Research Center of Personalized Anti-aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an, China
| | - Rui Guo
- Academy of Life Science, School of Medicine, Xi’an International University, Xi’an, China
- Engineering Research Center of Personalized Anti-aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an, China
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86
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Duan L, Qian X, Wang Q, Huang L, Ge S. Experimental Periodontitis Deteriorates Cognitive Function and Impairs Insulin Signaling in a Streptozotocin-Induced Alzheimer’s Disease Rat Model. J Alzheimers Dis 2022; 88:57-74. [PMID: 35527550 DOI: 10.3233/jad-215720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Background: With advancements in periodontal medicine, the relationship between periodontitis and systemic diseases has garnered increasing attention. Recently, emerging evidence has indicated that periodontitis may be involved in the pathogenesis of Alzheimer’s disease (AD). Objective: To assess the impact of experimental periodontitis on cognitive function deficits in a rat model of streptozotocin-induced AD and determine the mechanisms underlying these effects. Methods: Rats were randomly assigned to the control (C), experimental periodontitis (P), Alzheimer’s disease (AD), and experimental periodontitis with streptozotocin-induced AD (AD-P) groups. Experimental periodontitis was induced using ligation and coating with Porphyromonas gingivalis. In the AD-P group, AD was induced by intracerebroventricular injection of streptozotocin after 6 weeks of experimental periodontitis induction. Results: Compared with the group C rats, those in group P exhibited alveolar bone resorption, learning and memory function impairment, and decreased insulin sensitivity and insulin signaling-related protein expression. Glial cell activation and cognitive impairment in streptozotocin-induced groups with significantly increased phosphorylated tau levels were more pronounced relative to the C group. The number of neurons and insulin sensitivity and insulin signaling-related protein expression in group AD-P rats were lower than those in the AD alone group, while the expressions of glial fibrillary acidic protein, tau phosphorylation, interleukin-6, and cyclooxygenase-2 were significantly increased. Conclusion: Periodontitis may be a risk factor exacerbating cognitive deficits in an AD-like neurodegenerative context, possibly by impairing the insulin signaling pathway and stimulating gliosis and neuroinflammation.
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Affiliation(s)
- Lian Duan
- Hospital of Stomatology, Zunyi Medical University, Zunyi, Guizhou, China
| | - Xueshen Qian
- Hospital of Stomatology, Zunyi Medical University, Zunyi, Guizhou, China
| | - Qin Wang
- Hospital of Stomatology, Zunyi Medical University, Zunyi, Guizhou, China
| | - Lan Huang
- Hospital of Stomatology, Zunyi Medical University, Zunyi, Guizhou, China
| | - Song Ge
- Hospital of Stomatology, Zunyi Medical University, Zunyi, Guizhou, China
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87
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McManus RM. The Role of Immunity in Alzheimer's Disease. Adv Biol (Weinh) 2022; 6:e2101166. [PMID: 35254006 DOI: 10.1002/adbi.202101166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 02/03/2022] [Indexed: 01/27/2023]
Abstract
With the increase in the aging population, age-related conditions such as dementia and Alzheimer's disease will become ever more prevalent in society. As there is no cure for dementia and extremely limited therapeutic options, researchers are examining the mechanisms that contribute to the progression of cognitive decline in hopes of developing better therapies and even an effective, long-lasting treatment for this devastating condition. This review will provide an updated perspective on the role of immunity in triggering the changes that lead to the development of dementia. It will detail the latest findings on Aβ- and tau-induced microglial activation, including the role of the inflammasome. The contribution of the adaptive immune system, specifically T cells, will be discussed. Finally, whether the innate and adaptive immune system can be modulated to protect against dementia will be examined, along with an assessment of the prospective candidates for these that are currently in clinical trials.
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Affiliation(s)
- Róisín M McManus
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
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88
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Pritchard AB, Fabian Z, Lawrence CL, Morton G, Crean S, Alder JE. An Investigation into the Effects of Outer Membrane Vesicles and Lipopolysaccharide of Porphyromonas gingivalis on Blood-Brain Barrier Integrity, Permeability, and Disruption of Scaffolding Proteins in a Human in vitro Model. J Alzheimers Dis 2022; 86:343-364. [PMID: 35034897 DOI: 10.3233/jad-215054] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The effects of the key pathogens and virulence factors associated with gum disease such as Porphyromonas gingivalis (P. gingivalis) on the central nervous system is of great interest with respect to development of neuropathologies and hence therapeutics and preventative strategies. Chronic infections and associated inflammation are known to weaken the first line of defense for the brain, the blood-brain barrier (BBB). OBJECTIVE The focus of this study is to utilize an established human in vitro BBB model to evaluate the effects of P. gingivalis virulence factors lipopolysaccharide (LPS) and outer membrane vesicles (OMVs) on a primary-derived human model representing the neurovascular unit of the BBB. METHODS Changes to the integrity of the BBB after application of P. gingivalis LPS and OMVs were investigated and correlated with transport of LPS. Additionally, the effect of P. gingivalis LPS and OMVs on human brain microvascular endothelial cells in monolayer was evaluated using immunofluorescence microscopy. RESULTS The integrity of the BBB model was weakened by application of P. gingivalis LPS and OMVs, as measured by a decrease in electrical resistance and a recovery deficit was seen in comparison to the controls. Application of P. gingivalis OMVs to a monoculture of human brain microvascular endothelial cells showed disruption of the tight junction zona occludens protein (ZO-1) compared to controls. CONCLUSION These findings show that the integrity of tight junctions of the human BBB could be weakened by association with P. gingivalis virulence factors LPS and OMVs containing proteolytic enzymes (gingipains).
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Affiliation(s)
- Anna Barlach Pritchard
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Zsolt Fabian
- School of Medicine, University of Central Lancashire, Preston, UK
| | - Clare L Lawrence
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Glyn Morton
- School of Forensic and Investigative Science, University of Central Lancashire, Preston, UK
| | - StJohn Crean
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Jane E Alder
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
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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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Aravindraja C, Sakthivel R, Liu X, Goodwin M, Veena P, Godovikova V, Fenno JC, Levites Y, Golde TE, Kesavalu L. Intracerebral but Not Peripheral Infection of Live Porphyromonas gingivalis Exacerbates Alzheimer’s Disease like Amyloid Pathology in APP-TgCRND8 Mice. Int J Mol Sci 2022; 23:ijms23063328. [PMID: 35328748 PMCID: PMC8954230 DOI: 10.3390/ijms23063328] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/07/2022] [Accepted: 03/16/2022] [Indexed: 12/26/2022] Open
Abstract
The impact of oral microbial dysbiosis on Alzheimer’s disease (AD) remains controversial. Building off recent studies reporting that various microbes might directly seed or promote amyloid β (Aβ) deposition, we evaluated the effects of periodontal bacteria (Porphyromonas gingivalis, Treponema denticola) and supragingival commensal (Streptococcus gordonii) oral bacterial infection in the APP-transgenic CRND8 (Tg) mice model of AD. We tracked bacterial colonization and dissemination, and monitored effects on gliosis and amyloid deposition. Chronic oral infection did not accelerate Aβ deposition in Tg mice but did induce alveolar bone resorption, IgG immune response, and an intracerebral astrogliosis (GFAP: glial fibrillary acidic protein). In contrast, intracerebral inoculation of live but not heat-killed P. gingivalis increased Aβ deposition and Iba-1 (ionized calcium-binding adaptor-1) microgliosis after 8 weeks of bacterial infection but not at 4 days. These data show that there may be differential effects of infectious microbes on glial activation and amyloid deposition depending on the species and route of inoculation, and thereby provide an important framework for future studies. Indeed, these studies demonstrate marked effects on amyloid β deposition only in a fairly non-physiologic setting where live bacteria is injected directly into the brain.
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Affiliation(s)
- Chairmandurai Aravindraja
- Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA; (C.A.); (R.S.); (P.V.)
| | - Ravi Sakthivel
- Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA; (C.A.); (R.S.); (P.V.)
| | - Xuefei Liu
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (X.L.); (M.G.); (Y.L.)
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Marshall Goodwin
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (X.L.); (M.G.); (Y.L.)
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Patnam Veena
- Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA; (C.A.); (R.S.); (P.V.)
| | - Valentina Godovikova
- Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA; (V.G.); (J.C.F.)
| | - J. Christopher Fenno
- Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI 48109, USA; (V.G.); (J.C.F.)
| | - Yona Levites
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (X.L.); (M.G.); (Y.L.)
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Todd E. Golde
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (X.L.); (M.G.); (Y.L.)
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Correspondence: (T.E.G.); (L.K.); Tel.: +1-352-273-9456 (T.E.G.); +1-352-273-6500 (L.K.)
| | - Lakshmyya Kesavalu
- Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA; (C.A.); (R.S.); (P.V.)
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
- Correspondence: (T.E.G.); (L.K.); Tel.: +1-352-273-9456 (T.E.G.); +1-352-273-6500 (L.K.)
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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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92
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Thouvenot K, Turpin T, Taïlé J, Clément K, Meilhac O, Gonthier MP. Links between Insulin Resistance and Periodontal Bacteria: Insights on Molecular Players and Therapeutic Potential of Polyphenols. Biomolecules 2022; 12:biom12030378. [PMID: 35327570 PMCID: PMC8945445 DOI: 10.3390/biom12030378] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 02/07/2023] Open
Abstract
Type 2 diabetes is a metabolic disease mainly associated with insulin resistance during obesity and constitutes a major public health problem worldwide. A strong link has been established between type 2 diabetes and periodontitis, an infectious dental disease characterized by chronic inflammation and destruction of the tooth-supporting tissue or periodontium. However, the molecular mechanisms linking periodontal bacteria and insulin resistance remain poorly elucidated. This study aims to summarize the mechanisms possibly involved based on in vivo and in vitro studies and targets them for innovative therapies. Indeed, during periodontitis, inflammatory lesions of the periodontal tissue may allow periodontal bacteria to disseminate into the bloodstream and reach tissues, including adipose tissue and skeletal muscles that store glucose in response to insulin. Locally, periodontal bacteria and their components, such as lipopolysaccharides and gingipains, may deregulate inflammatory pathways, altering the production of pro-inflammatory cytokines/chemokines. Moreover, periodontal bacteria may promote ROS overproduction via downregulation of the enzymatic antioxidant defense system, leading to oxidative stress. Crosstalk between players of inflammation and oxidative stress contributes to disruption of the insulin signaling pathway and promotes insulin resistance. In parallel, periodontal bacteria alter glucose and lipid metabolism in the liver and deregulate insulin production by pancreatic β-cells, contributing to hyperglycemia. Interestingly, therapeutic management of periodontitis reduces systemic inflammation markers and ameliorates insulin sensitivity in type 2 diabetic patients. Of note, plant polyphenols exert anti-inflammatory and antioxidant activities as well as insulin-sensitizing and anti-bacterial actions. Thus, polyphenol-based therapies are of high interest for helping to counteract the deleterious effects of periodontal bacteria and improve insulin resistance.
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Affiliation(s)
- Katy Thouvenot
- Université de La Réunion, Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), 97490 Saint-Denis de La Réunion, France; (K.T.); (T.T.); (J.T.); (O.M.)
| | - Teva Turpin
- Université de La Réunion, Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), 97490 Saint-Denis de La Réunion, France; (K.T.); (T.T.); (J.T.); (O.M.)
| | - Janice Taïlé
- Université de La Réunion, Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), 97490 Saint-Denis de La Réunion, France; (K.T.); (T.T.); (J.T.); (O.M.)
| | - Karine Clément
- Nutrition and Obesity, Systemic Approaches (NutriOmics), INSERM, Sorbonne Université, 75013 Paris, France
| | - Olivier Meilhac
- Université de La Réunion, Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), 97490 Saint-Denis de La Réunion, France; (K.T.); (T.T.); (J.T.); (O.M.)
| | - Marie-Paule Gonthier
- Université de La Réunion, Inserm, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), 97490 Saint-Denis de La Réunion, France; (K.T.); (T.T.); (J.T.); (O.M.)
- Correspondence: ; Tel.: +33-262-693-92-08-55
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93
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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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Guan Y, Zhang L, Wang S, Deng Y, Zhou H, Chen D, Zhang L. The role of microglia in Alzheimer's disease and progress of treatment. IBRAIN 2022; 8:37-47. [PMID: 37786418 PMCID: PMC10529349 DOI: 10.1002/ibra.12023] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 10/04/2023]
Abstract
Microglia are permanent immune cells of the central nervous system. Microglia play an important role in the pathological process of Alzheimer's disease (AD). They are mainly involved in the uptake and clearance of amyloid-β (Aβ), as well as the formation of neuroinflammation. We found that overactivated microglia increase Aβ and Tau, and Aβ and Tau in turn act as activators of microglia. Additionally, various cytokines and proteins, high cholesterol, and telomere shortening are all associated with microglia activation. More activated microglia induce the release of inflammatory and anti-inflammatory factors to regulate inflammation, while microglia express multiple homologous receptors that bind to neuroimmunomodulators to prevent microglia overactivation. Moreover, aging of the body promotes neuroinflammation by increasing the response to IFN-γ (interferon-γ), and aging of the microglia themselves promotes AD by inducing the accumulation of large amounts of iron and reducing autophagy by regulating protein levels. Cognitive dysfunction occurs when activated microglia induce an increase in beta oligomers, promoting the production of pro-inflammatory factors that alter the shape, composition, and density of synapses. Based on their correlation, microglia-mediated AD therapy as well as the corresponding targets and drugs are discussed. In contrast to similar reviews, this article also summarizes some novel microglia-mediated AD treatment methods over the recent years.
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Affiliation(s)
- Yi‐Huan Guan
- Department of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Ling‐Jing Zhang
- Department of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Shi‐Ya Wang
- Department of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Ya‐Dan Deng
- Department of AnesthesiologyZunyi Medical UniversityZunyiGuizhouChina
| | - Hong‐Su Zhou
- Department of AnesthesiaGraduate School of Zunyi Medical UniversityZunyiGuizhouChina
| | - Dong‐Qing Chen
- Department of AnesthesiaGraduate School of Zunyi Medical UniversityZunyiGuizhouChina
| | - Lan‐Chun Zhang
- Department of ZoologyKunming Medical UniversityKunmingChina
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Kim HS, Son J, Lee D, Tsai J, Wang D, Chocron ES, Jeong S, Kittrell P, Murchison CF, Kennedy RE, Tobon A, Jackson CE, Pickering AM. Gut- and oral-dysbiosis differentially impact spinal- and bulbar-onset ALS, predicting ALS severity and potentially determining the location of disease onset. BMC Neurol 2022; 22:62. [PMID: 35189854 PMCID: PMC8862222 DOI: 10.1186/s12883-022-02586-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/04/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Prior studies on the role of gut-microbiome in Amyotrophic Lateral Sclerosis (ALS) pathogenesis have yielded conflicting results. We hypothesized that gut- and oral-microbiome may differentially impact two clinically-distinct ALS subtypes (spinal-onset ALS (sALS) vs. bulbar-onset ALS (bALS), driving disagreement in the field. METHODS ALS patients diagnosed within 12 months and their spouses as healthy controls (n = 150 couples) were screened. For eligible sALS and bALS patients (n = 36) and healthy controls (n = 20), 16S rRNA next-generation sequencing was done in fecal and saliva samples after DNA extractions to examine gut- and oral-microbiome differences. Microbial translocation to blood was measured by blood lipopolysaccharide-binding protein (LBP) and 16S rDNA levels. ALS severity was assessed by Revised ALS Functional Rating Scale (ALSFRS-R). RESULTS sALS patients manifested significant gut-dysbiosis, primarily driven by increased fecal Firmicutes/Bacteroidetes-ratio (F/B-ratio). In contrast, bALS patients displayed significant oral-dysbiosis, primarily driven by decreased oral F/B-ratio. For sALS patients, gut-dysbiosis (a shift in fecal F/B-ratio), but not oral-dysbiosis, was strongly associated with greater microbial translocation to blood (r = 0.8006, P < 0.0001) and more severe symptoms (r = 0.9470, P < 0.0001). In contrast, for bALS patients, oral-dysbiosis (a shift in oral F/B-ratio), but not gut-dysbiosis, was strongly associated with greater microbial translocation to blood (r = 0.9860, P < 0.0001) and greater disease severity (r = 0.9842, P < 0.0001). For both ALS subtypes, greater microbial translocation was associated with more severe symptoms (sALS: r = 0.7924, P < 0.0001; bALS: r = 0.7496, P = 0.0067). Importantly, both sALS and bALS patients displayed comparable oral-motor deficits with associations between oral-dysbiosis and severity of oral-motor deficits in bALS but not sALS. This suggests that oral-dysbiosis is not simply caused by oral/bulbar/respiratory symptoms but represents a pathological driver of bALS. CONCLUSIONS We found increasing gut-dysbiosis with worsening symptoms in sALS patients and increasing oral-dysbiosis with worsening symptoms in bALS patients. Our findings support distinct microbial mechanisms underlying two ALS subtypes, which have been previously grouped together as a single disease. Our study suggests correcting gut-dysbiosis as a therapeutic strategy for sALS patients and correcting oral-dysbiosis as a therapeutic strategy for bALS patients.
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Affiliation(s)
- Harper S Kim
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
- Medical Scientist Training Program, University of Alabama at Birmingham, Birmingham, AL, USA
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA
- Medical Scientist Training Program, University of Texas Health San Antonio, San Antonio, TX, USA
| | - John Son
- Department of Anesthesiology, University of California Irvine, Irvine, CA, USA
- School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Donghwan Lee
- School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
- Department of Anesthesiology, Massachusetts General Hospital, Boston, MA, USA
| | - Joy Tsai
- School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
- Department of Anesthesiology, Stanford University, Stanford, CA, USA
| | - Danny Wang
- School of Nursing, University of Alabama at Birmingham, Birmingham, AL, USA
| | - E Sandra Chocron
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Seongwoo Jeong
- School of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Pamela Kittrell
- Department of Neurology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Charles F Murchison
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Richard E Kennedy
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Alejandro Tobon
- Department of Neurology, South Texas Veteran Health Care System, San Antonio, TX, USA
| | - Carlayne E Jackson
- Department of Neurology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Andrew M Pickering
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA.
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, TX, USA.
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Hu J, Wang X. Alzheimer’s Disease: From Pathogenesis to Mesenchymal Stem Cell Therapy – Bridging the Missing Link. Front Cell Neurosci 2022; 15:811852. [PMID: 35197824 PMCID: PMC8859419 DOI: 10.3389/fncel.2021.811852] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/02/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease worldwide. With the increasing trend of population aging, the estimated number of AD continues to climb, causing enormous medical, social and economic burden to the society. Currently, no drug is available to cure the disease or slow down its progression. There is an urgent need to improve our understanding on the pathogenesis of AD and develop novel therapy to combat it. Despite the two well-known pathological hallmarks (extracellular amyloid plaques and intracellular Neurofibrillary Tangles), the exact mechanisms for selective degeneration and loss of neurons and synapses in AD remain to be elucidated. Cumulative studies have shown neuroinflammation plays a central role in pathogenesis of AD. Neuroinflammation is actively involved both in the onset and the subsequent progression of AD. Microglia are the central player in AD neuroinflammation. In this review, we first introduced the different theories proposed for the pathogenesis of AD, focusing on neuroinflammation, especially on microglia, systemic inflammation, and peripheral and central immune system crosstalk. We explored the possible mechanisms of action of stem cell therapy, which is the only treatment modality so far that has pleiotropic effects and can target multiple mechanisms in AD. Mesenchymal stem cells are currently the most widely used stem cell type in AD clinical trials. We summarized the ongoing major mesenchymal stem cell clinical trials in AD and showed how translational stem cell therapy is bridging the gap between basic science and clinical intervention in this devastating disorder.
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Affiliation(s)
- Jingqiong Hu
- Stem Cell Center, Department of Cell Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Jingqiong Hu,
| | - Xiaochuan Wang
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry/Hubei Province of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Elgreu T, Lee S, Wen S, Elghadafi R, Tangkham T, Ma Y, Liu B, Dibart S, Tang X. The pathogenic mechanism of oral bacteria and treatment with inhibitors. Clin Exp Dent Res 2022; 8:439-448. [PMID: 34626163 PMCID: PMC8874083 DOI: 10.1002/cre2.499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 08/17/2021] [Accepted: 08/23/2021] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVES The objective of this study was to introduce the evidence obtained through extensive research that periodontitis increases risk of many systemic diseases. METHOD Analysis of some oral bacteria (P. gingivalis, T. denticola, T. forsythia, A. actinomycetemcomitans, and F. nucleatum) and its related treatments and mediators by the specific methods (western blot, ELISA, etc). RESULTS This article reviews in detail the evidence obtained through extensive research that periodontitis increases risk of many systemic diseases, including cardiovascular disease, rheumatoid arthritis, and Alzheimer's disease. These diseases are known to be associated with some certain specific gram-negative bacteria as periodontal pathogens, which induce inflammation and related diseases through TLR receptors, kinases, transcriptional factors and other cytokines. We also reviewed the latest research for inhibitors against inflammation and related diseases that have potential to be further applied clinically. In addition, based on a large amount of research evidence, we draw two tables about the mechanism of disease caused by periodontal bacteria, so that readers can easily search and analyze these research results. DISCUSSION This review details how the periodontal bacteria and their virulence factors can trigger host immune defense and induce many systemic diseases via inflammation and invasion. This Review also addressed the latest research around inhibitors against inflammation.
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Affiliation(s)
- Thuraya Elgreu
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
| | - Sean Lee
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
| | - Sabrina Wen
- Department of Corporate Finance and AccountingBentley UniversityWalthamMassachusettsUSA
| | - Radwa Elghadafi
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
| | - Thanarut Tangkham
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
| | - Yun Ma
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
| | - Bing Liu
- Henry M. Goldman School of Dental Medicine, Department of General DentistryBoston UniversityBostonMassachusettsUSA
| | - Serge Dibart
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
| | - Xiaoren Tang
- Henry M. Goldman School of Dental Medicine, Department of PeriodontologyBoston UniversityBostonMassachusettsUSA
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98
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Phuna ZX, Madhavan P. A CLOSER LOOK AT THE MYCOBIOME IN ALZHEIMER'S DISEASE: FUNGAL SPECIES, PATHOGENESIS AND TRANSMISSION. Eur J Neurosci 2022; 55:1291-1321. [DOI: 10.1111/ejn.15599] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Zhi Xin Phuna
- School of Medicine, Faculty of Health & Medical Sciences, Taylor’s University Malaysia Subang Jaya Selangor
| | - Priya Madhavan
- School of Medicine, Faculty of Health & Medical Sciences, Taylor’s University Malaysia Subang Jaya Selangor
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99
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Nonaka S, Kadowaki T, Nakanishi H. Secreted gingipains from Porphyromonas gingivalis increase permeability in human cerebral microvascular endothelial cells through intracellular degradation of tight junction proteins. Neurochem Int 2022; 154:105282. [PMID: 35032577 DOI: 10.1016/j.neuint.2022.105282] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/21/2021] [Accepted: 01/10/2022] [Indexed: 12/14/2022]
Abstract
Despite a clear correlation between the infiltration of periodontal pathogens in the brain and cognitive decline in Alzheimer's disease (AD), the precise mechanism underlying bacteria crossing the blood-brain barrier (BBB) remains unclear. The periodontal pathogen Porphyromonas gingivalis produces a unique class of cysteine proteases termed gingipains. Gingipains appear to be key virulence factors that exacerbate sporadic AD. We herein report that gingipains are involved in increasing permeability of hCMEC/D3 cell monolayer, human cerebral microvascular endothelial cell lines, through degradation of tight junction proteins including zonula occludens (ZO-1) and occludin. There was a significant decrease in the mean protein levels of ZO-1 and occludin after infection of hCMEC/D3 cells with wild-type (WT) P. gingivalis. However, infection of these cells with a gingipain-deficient P. gingivalis strain showed significantly lower reduction of the mean protein levels of either ZO-1 and occludin, compared to the WT strain. Similar results were obtained after treatment with culture supernatant from WT and gingipain-deficient P. gingivalis strains. In vitro digestion of human recombinant ZO-1 and occludin by WT P. gingivalis culture supernatant in the absence or presence of gingipain inhibitors indicated that gingipains directly degraded these tight junction proteins. A close immunohistochemical examination using anti-gingipain antibody further revealed that gingipains localized in the cytosol and nuclei of hCMEC/D3 cells after infection with WT P. gingivalis and treatment with its culture supernatant. Furthermore, intracellular localization of outer membrane vesicles (OMVs) bound gingipains from WT P. gingivalis and OMV-induced degradation of ZO-1 and occludin were also observed in hCMEC/D3 cells. Thus, the delivery of gingipains into the cerebral microvascular endothelial cells, probably through OMV, may be responsible for the BBB damage through intracellular degradation of ZO-1 and occludin.
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Affiliation(s)
- Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan.
| | - Tomoko Kadowaki
- Department of Frontier Oral Science, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, 852-8588, Japan
| | - Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women's University, Hiroshima, 731-0153, Japan.
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100
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Chouhan JK, Püntener U, Booth SG, Teeling JL. Systemic Inflammation Accelerates Changes in Microglial and Synaptic Markers in an Experimental Model of Chronic Neurodegeneration. Front Neurosci 2022; 15:760721. [PMID: 35058740 PMCID: PMC8764443 DOI: 10.3389/fnins.2021.760721] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/30/2021] [Indexed: 12/01/2022] Open
Abstract
Bacterial infections are a common cause of morbidity and mortality in the elderly, and particularly in individuals with a neurodegenerative disease. Experimental models of neurodegeneration have shown that LPS-induced systemic inflammation increases neuronal damage, a process thought to be mediated by activation of "primed" microglia. The effects of a real systemic bacterial infection on the innate immune cells in the brain and neuronal networks are less well described, and therefore, in this study we use the ME7 prion model to investigate the alterations in microglia activation and phenotype and synaptic markers in response to a low grade, live bacterial infection. Mice with or without a pre-existing ME7 prion-induced neurodegenerative disease were given a single systemic injection of live Salmonella typhimurium at early or mid-stage of disease progression. Immune activation markers CD11b and MHCII and pro-inflammatory cytokines were analyzed 4 weeks post-infection. Systemic infection with S. typhimurium resulted in an exaggerated inflammatory response when compared to ME7 prion mice treated with saline. These changes to inflammatory markers were most pronounced at mid-stage disease. Analysis of synaptic markers in ME7 prion mice revealed a significant reduction of genes that are associated with early response in synaptic plasticity, extracellular matrix structure and post-synaptic density, but no further reduction following systemic infection. In contrast, analysis of activity-related neuronal receptors involved in development of learning and memory, such as Grm1 and Grin2a, showed a significant decrease in response to systemic bacterial challenge. These changes were observed early in the disease progression and associated with reduced burrowing activity. The exaggerated innate immune activation and altered expression of genes linked to synaptic plasticity may contribute to the onset and/or progression of neurodegeneration.
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Affiliation(s)
| | | | | | - Jessica L. Teeling
- Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
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