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Dai X, Liang R, Dai M, Li X, Zhao W. Smoking Impacts Alzheimer's Disease Progression Through Oral Microbiota Modulation. Mol Neurobiol 2024:10.1007/s12035-024-04241-1. [PMID: 38795302 DOI: 10.1007/s12035-024-04241-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 05/13/2024] [Indexed: 05/27/2024]
Abstract
Alzheimer's disease (AD) is an important public health challenge with a limited understanding of its pathogenesis. Smoking is a significant modifiable risk factor for AD progression, and its specific mechanism is often interpreted from a toxicological perspective. However, microbial infections also contribute to AD, with oral microbiota playing a crucial role in its progression. Notably, smoking alters the ecological structure and pathogenicity of the oral microbiota. Currently, there is no systematic review or summary of the relationship between these three factors; thus, understanding this association can help in the development of new treatments. This review summarizes the connections between smoking, AD, and oral microbiota from existing research. It also explores how smoking affects the occurrence and development of AD through oral microbiota, and examines treatments for oral microbiota that delay the progression of AD. Furthermore, this review emphasizes the potential of the oral microbiota to act as a biomarker for AD. Finally, it considers the feasibility of probiotics and oral antibacterial therapy to expand treatment methods for AD.
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Affiliation(s)
- Xingzhu Dai
- Department of Stomatology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Rui Liang
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Manqiong Dai
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoyu Li
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Wanghong Zhao
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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Williams ZAP, Lang L, Nicolas S, Clarke G, Cryan J, Vauzour D, Nolan YM. Do microbes play a role in Alzheimer's disease? Microb Biotechnol 2024; 17:e14462. [PMID: 38593310 PMCID: PMC11003713 DOI: 10.1111/1751-7915.14462] [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: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 04/11/2024] Open
Abstract
Alzheimer's disease is a complex and progressive condition that affects essential neurological functions such as memory and reasoning. In the brain, neuronal loss, synaptic dysfunction, proteinopathy, neurofibrillary tangles, and neuroinflammation are the hallmarks of Alzheimer's disease pathophysiology. In addition, recent evidence has highlighted that microbes, whether commensal or pathogenic, also have the ability to interact with their host and to regulate its immune system, therefore participating in the exchanges that lead to peripheral inflammation and neuropathology. Because of this intimate relationship, bacteria, viruses, fungi, and protozoa have been implicated in the development of Alzheimer's disease. Here, we bring together current and most recent evidence of the role of microbes in Alzheimer's disease, raising burning questions that need to be addressed to guide therapeutic approaches and potential prophylactic strategies.
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Affiliation(s)
- Zoë A. P. Williams
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Leonie Lang
- Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
| | - Sarah Nicolas
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Gerard Clarke
- APC Microbiome IrelandUniversity College CorkCorkIreland
- Department of Psychiatry and Neurobehavioural ScienceUniversity College CorkCorkIreland
| | - John Cryan
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - David Vauzour
- Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
| | - Yvonne M. Nolan
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
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Shen H, Jiang Y, Qiu C, Xie X, Zhang H, He Z, Song Z, Zhou W. Abnormal amyloid precursor protein processing in periodontal tissue in a murine model of periodontitis induced by Porphyromonas gingivalis. J Periodontal Res 2024; 59:395-407. [PMID: 38311599 DOI: 10.1111/jre.13224] [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: 01/30/2023] [Revised: 11/27/2023] [Accepted: 12/05/2023] [Indexed: 02/06/2024]
Abstract
OBJECTIVE The study aimed to investigate the change of amyloid precursor protein (APP) processing and amyloid β (Aβ) metabolites in linking periodontitis to Alzheimer's disease (AD). BACKGROUND Aβ is one of the main pathological features of AD, and few studies have discussed changes in its expression in peripheral tissues or analyzed the relationship between the peripheral imbalance of Aβ production and clearance. METHODS A murine model of periodontitis was established by oral infection with Porphyromonas gingivalis (P. gingivalis). Micro-computed tomography (Micro-CT) was used to observe the destruction of the alveolar bone. Nested quantitative polymerase chain reaction (qPCR) was used to measure small quantities of P.gingivalis DNA in different tissues. Behavioral experiments were performed to measure cognitive function in the mice. The mRNA levels of TNF-α, IL-6, IL-8, RANKL, OPG, APP695, APP751, APP770, and BACE1 in the gingival tissues or cortex were detected by RT-PCR. The levels of Aβ1-40 and Aβ1-42 in gingival crevicular fluid (GCF) and plasma were tested by ELISA. RESULTS P. gingivalis oral infection was found to cause alveolar bone resorption and impaired learning and memory. P.gingivalis DNA was detected in the gingiva, blood and cortex of the P.gingivalis group by nested qPCR (p < .05). The mRNA expression of TNF-α, IL-6, IL-8, RANKL/OPG, and BACE1 in the gingival tissue was significantly higher than that in the control group (p < .05). Similarly, upregulated mRNA levels of APP695 and APP770 were observed in the gingival tissuses and cortex of the P. gingivalis group (p < .05). The levels of Aβ1-40 and Aβ1-42 in the GCF and plasma of the P. gingivalis group were significantly higher than those in the control group (p < .05). CONCLUSION P. gingivalis can directly invade the brain via hematogenous infection. The invasion of P. gingivalis could trigger an immune response and lead to an imbalance between Aβ production and clearance in peripheral tissues, which may trigger an abnormal Aβ metabolite in the brain, resulting in the occurrence and development of AD.
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Affiliation(s)
- Hui Shen
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Yiting Jiang
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Che Qiu
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Xinyi Xie
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Huanyu Zhang
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Zhiyan He
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhongchen Song
- Department of Periodontology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Wei Zhou
- National Center for Stomatology, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai, China
- Laboratory of Oral Microbiota and Systemic Diseases, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
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Li R, Wang J, Xiong W, Luo Y, Feng H, Zhou H, Peng Y, He Y, Ye Q. The oral-brain axis: can periodontal pathogens trigger the onset and progression of Alzheimer's disease? Front Microbiol 2024; 15:1358179. [PMID: 38362505 PMCID: PMC10868393 DOI: 10.3389/fmicb.2024.1358179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by a progressive cognitive decline. Sporadic AD, accounting for more than 95% of cases, may arise due to the influence of environmental factors. It was reported that periodontitis, a common oral ailment, shares several risk factors with AD, including advanced age, smoking, diabetes, and hypertension, among others. Periodontitis is an inflammatory disease triggered by dysbiosis of oral microorganisms, whereas Alzheimer's disease is characterized by neuroinflammation. Many studies have indicated that chronic inflammation can instigate brain AD-related pathologies, including amyloid-β plaques, Tau protein hyperphosphorylation, neuroinflammation, and neurodegeneration. The potential involvement of periodontal pathogens and/or their virulence factors in the onset and progression of AD by the oral-brain axis has garnered significant attention among researchers with ongoing investigations. This review has updated the periodontal pathogens potentially associated with AD, elucidating their impact on the central nervous system, immune response, and related pathological processes in the brain to provide valuable insights for future research on the oral-brain axis.
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Affiliation(s)
- Ruohan Li
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Junnan Wang
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wei Xiong
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yu Luo
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Huixian Feng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Heng Zhou
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Youjian Peng
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Yan He
- Institute of Regenerative and Translational Medicine, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, China
| | - Qingsong Ye
- Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
- Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
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Li Z, Wang H, Yin Y. Peripheral inflammation is a potential etiological factor in Alzheimer's disease. Rev Neurosci 2024; 35:99-120. [PMID: 37602685 DOI: 10.1515/revneuro-2023-0049] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/27/2023] [Indexed: 08/22/2023]
Abstract
Peripheral inflammation could constitute a risk factor for AD. This review summarizes the research related to peripheral inflammation that appears to have a relationship with Alzheimer's disease. We find there are significant associations between AD and peripheral infection induced by various pathogens, including herpes simplex virus type 1, cytomegalovirus, Epstein-Barr virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, Porphyromonas gingivalis, Helicobacter pylori, and Toxoplasma gondii. Chronic inflammatory diseases are also reported to contribute to the pathophysiology of AD. The mechanisms by which peripheral inflammation affects the pathophysiology of AD are complex. Pathogen-derived neurotoxic molecule composition, disrupted BBB, and dysfunctional neurogenesis may all play a role in peripheral inflammation, promoting the development of AD. Anti-pathogenic medications and anti-inflammatory treatments are reported to decrease the risk of AD. Studies that could improve understanding the associations between AD and peripheral inflammation are needed. If our assumption is correct, early intervention against inflammation may be a potential method of preventing and treating AD.
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Affiliation(s)
- Ziyuan Li
- Department of Nuclear Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Yangpu District, Shanghai 200092, China
| | - Hui Wang
- Department of Nuclear Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Yangpu District, Shanghai 200092, China
| | - Yafu Yin
- Department of Nuclear Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Kongjiang Road 1665, Yangpu District, Shanghai 200092, China
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Bello-Corral L, Alves-Gomes L, Fernández-Fernández JA, Fernández-García D, Casado-Verdejo I, Sánchez-Valdeón L. Implications of gut and oral microbiota in neuroinflammatory responses in Alzheimer's disease. Life Sci 2023; 333:122132. [PMID: 37793482 DOI: 10.1016/j.lfs.2023.122132] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023]
Abstract
A diverse and stable microbiota promotes a healthy state, nevertheless, an imbalance in gut or oral bacterial composition, called dysbiosis, can cause gastrointestinal disorders, systemic inflammatory states and oxidative stress, among others. Recently, gut and oral dysbiosis has been linked to Alzheimer's disease (AD), which is considered the most common form of dementia and a public health priority due to its high prevalence and incidence. The aim of this review is to highlight the implications of gut and oral microbiota in the neuroinflammation characteristic of AD pathology and the subsequent cognitive impairment. It is a systematic review of the current literature obtained by searching the PubMed, Web of Science and Scopus databases. The characteristic intestinal dysbiosis in AD patients leads to increased permeability of the intestinal barrier and activates immune cells in the central nervous system due to translocation of microbiota-derived metabolites and/or bacteria into the circulation leading to increased neuroinflammation and neuronal loss, thus generating the cognitive impairment characteristic of AD. The presence in the central nervous system of Porphyromonas gingivalis can cause an increased neuroinflammation and beta-amyloid peptide accumulation.
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Affiliation(s)
- Laura Bello-Corral
- Health Research Nursing Group (GREIS), University of Leon, 24071, Leon, Spain; Department of Nursing and Physiotherapy, University of Leon, 24071, Leon, Spain
| | | | - Jesús Antonio Fernández-Fernández
- Health Research Nursing Group (GREIS), University of Leon, 24071, Leon, Spain; Department of Nursing and Physiotherapy, University of Leon, 24071, Leon, Spain
| | - Daniel Fernández-García
- Health Research Nursing Group (GREIS), University of Leon, 24071, Leon, Spain; Department of Nursing and Physiotherapy, University of Leon, 24071, Leon, Spain
| | - Inés Casado-Verdejo
- Health Research Nursing Group (GREIS), University of Leon, 24071, Leon, Spain; Department of Nursing and Physiotherapy, University of Leon, 24401, Ponferrada, Spain
| | - Leticia Sánchez-Valdeón
- Health Research Nursing Group (GREIS), University of Leon, 24071, Leon, Spain; Department of Nursing and Physiotherapy, University of Leon, 24071, Leon, Spain.
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Park S, Kim I, Han SJ, Kwon S, Min EJ, Cho W, Koh H, Koo BN, Lee JS, Kwon JS, Seo KY, Ha JW, Park YM. Oral Porphyromonas gingivalis infection affects intestinal microbiota and promotes atherosclerosis. J Clin Periodontol 2023; 50:1553-1567. [PMID: 37621247 DOI: 10.1111/jcpe.13864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 06/19/2023] [Accepted: 08/01/2023] [Indexed: 08/26/2023]
Abstract
AIM The link between periodontitis and intestinal dysbiosis, two factors that contribute to atherosclerosis, has not been clearly defined. We investigated the integrative effects of oral infection with Porphyromonas gingivalis (PG), the major pathogen for periodontitis, on intestinal microbiota and atherosclerosis. MATERIALS AND METHODS ApoE-/- mice were fed a normal chow diet (NC), a Western diet (WD) or a WD with oral PG infection (PG). The PG infection was investigated by placing a total of 109 CFUs of live PG into the oral cavity of each mouse using a feeding needle five times a week for 3 weeks. Atherosclerotic lesions of the aortae were measured, and blood lipoproteins and the expression of molecules related to lipid metabolism in the liver were analysed. We also performed 16S RNA sequencing and a microbiome analysis using faeces. RESULTS En face bloc preparation of the aortae showed that the PG group had a 1.7-fold increase in atherosclerotic lesions compared with the WD group (p < .01). Serum analyses showed that oral PG infection induced a significant decrease in high-density lipoprotein (HDL) and triglyceride. Western blots of hepatic tissue lysates revealed that PG infection reduced the expression of scavenger receptor class B type 1 (SR-B1) in the liver by 50%. Faecal microbiota analysis revealed that species richness estimates (Chao1, ACE) decreased immediately after PG infection. PG infection also induced a significant decrease in Shannon diversity and an increase in Simpson's indices in the WD-fed mice. PG infection significantly increased the phyla Actinobacteria and Deferribacteres, along with the species Mucispirillum schaedleri and Lactobacillus gasseri, in the mice. The functional study showed that PG infection increased the expression of proteins that function in carbohydrate and glucose metabolism, including phosphotransferase system (PTS) proteins and the GntR family transcriptional regulator. CONCLUSIONS Oral PG infection promotes atherosclerosis and induces significant metabolic changes, including reduced serum HDL and reduced hepatic SR-B1 and ABCA1 expression, as well as changes in intestinal microbiota. Our study suggests that intestinal dysbiosis accompanies periodontitis and could play a role in atherosclerosis.
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Affiliation(s)
- Sowon Park
- Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Inyoung Kim
- Department of Molecular Medicine, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Soo Jung Han
- Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, South Korea
| | - Soyeon Kwon
- Department of Molecular Medicine, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Eun-Ji Min
- Department of Molecular Medicine, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Wonkyoung Cho
- Department of Molecular Medicine, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Hong Koh
- Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Bon-Nyeo Koo
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Jung Seok Lee
- Department of Periodontics, Yonsei University College of Dentistry, Seoul, South Korea
| | - Jae-Sung Kwon
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, Seoul, South Korea
| | - Kyoung Yul Seo
- Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, South Korea
| | - Jong-Won Ha
- Cardiology Division, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Young Mi Park
- Department of Molecular Medicine, Ewha Womans University College of Medicine, Seoul, South Korea
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Zhou X, Kumar P, Bhuyan DJ, Jensen SO, Roberts TL, Münch GW. Neuroinflammation in Alzheimer's Disease: A Potential Role of Nose-Picking in Pathogen Entry via the Olfactory System? Biomolecules 2023; 13:1568. [PMID: 38002250 PMCID: PMC10669446 DOI: 10.3390/biom13111568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by progressive cognitive decline and memory impairment. Many possible factors might contribute to the development of AD, including amyloid peptide and tau deposition, but more recent evidence suggests that neuroinflammation may also play an-at least partial-role in its pathogenesis. In recent years, emerging research has explored the possible involvement of external, invading pathogens in starting or accelerating the neuroinflammatory processes in AD. In this narrative review, we advance the hypothesis that neuroinflammation in AD might be partially caused by viral, bacterial, and fungal pathogens entering the brain through the nose and the olfactory system. The olfactory system represents a plausible route for pathogen entry, given its direct anatomical connection to the brain and its involvement in the early stages of AD. We discuss the potential mechanisms through which pathogens may exploit the olfactory pathway to initiate neuroinflammation, one of them being accidental exposure of the olfactory mucosa to hands contaminated with soil and feces when picking one's nose.
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Affiliation(s)
- Xian Zhou
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (X.Z.); (D.J.B.)
| | - Paayal Kumar
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia;
| | - Deep J. Bhuyan
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (X.Z.); (D.J.B.)
| | - Slade O. Jensen
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia; (S.O.J.); (T.L.R.)
- Microbiology and Infectious Diseases Unit, School of Medicine, Western Sydney University, Liverpool, NSW 2170, Australia
| | - Tara L. Roberts
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia; (S.O.J.); (T.L.R.)
- Oncology Unit, School of Medicine, Western Sydney University, Liverpool, NSW 2170, Australia
| | - Gerald W. Münch
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (X.Z.); (D.J.B.)
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia;
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Eslami S, Hosseinzadeh Shakib N, Fooladfar Z, Nasrollahian S, Baghaei S, Mosaddad SA, Motamedifar M. The role of periodontitis-associated bacteria in Alzheimer's disease: A narrative review. J Basic Microbiol 2023; 63:1059-1072. [PMID: 37311215 DOI: 10.1002/jobm.202300250] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/01/2023] [Accepted: 06/03/2023] [Indexed: 06/15/2023]
Abstract
Alzheimer's disease causes memory loss and dementia in older adults through a neurodegenerative mechanism. Despite the pathophysiological clarification of this cognitive disorder, novel molecular and cellular pathways should be identified to determine its exact mechanism. Alzheimer's disease (AD) is pathologically characterized by senile plaques comprising beta-amyloid and neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau as a microtubule-associated protein with a key role in the pathogenesis of AD. Periodontitis through inflammatory pathways is a risk factor for deteriorating cognitive impairment in AD patients. Poor oral hygiene coupled with immunocompromised status in older adults causes periodontal diseases and chronic inflammations through an oral bacterial imbalance. Toxic bacterial products, including bacteria themselves, can reach the central nervous system through the bloodstream and evoke inflammatory responses. The present review was conducted to investigate relationships between AD and periodontitis-involved bacteria as a risk factor.
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Affiliation(s)
- Saba Eslami
- Research Central Laboratory, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Zahra Fooladfar
- Student Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sina Nasrollahian
- Student Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saman Baghaei
- Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyed Ali Mosaddad
- Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Motamedifar
- HIV/AIDS Research Center, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran
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10
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Zhang Y, Sun Y, Hu Y, Zheng S, Shao H, Lin L, Pan Y, Li C. Porphyromonas gingivalis msRNA P.G_45033 induces amyloid-β production by enhancing glycolysis and histone lactylation in macrophages. Int Immunopharmacol 2023; 121:110468. [PMID: 37320870 DOI: 10.1016/j.intimp.2023.110468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/24/2023] [Accepted: 06/06/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND High expression of amyloid-β (Aβ) in periodontal tissue could contribute to exacerbating the development of both periodontitis and Alzheimer's disease (AD). Porphyromonas gingivalis (P. gingivalis) as a periodontal pathogen expresses msRNAs, which can regulate gene transcription in host cells. OBJECTIVE The aim of this study is to reveal the mechanism of msRNA P.G_45033, a high copy msRNA in P. gingivalis, inducing Aβ expression in macrophages, and provide a new insight to explain the development of periodontitis, and also to explain the role of periodontal infection on AD. METHODS The levels of glucose consumption, pyruvate and lactate productions in macrophages after transfection with msRNA P.G_45033 were detected. Miranda, TargetScan, and RNAhybrid databases were used to predict the target gene of msRNA P.G_45033, and GO analysis was conducted to describe the functions of the overlapping ones. RT2 glucose-metabolism PCR Array was used to verify the relationship between msRNA P.G_45033 and the expression of genes related to glucose metabolism. The levels of histone Kla were detected using western blotting. The levels of Aβ in the macrophages and the culture medium were detected by immunofluorescence and ELISA, respectively. RESULTS The levels of glucose consumption, pyruvate and lactate productions were increased after transfection of msRNA P.G_45033 in macrophages. GO analysis revealed that target genes were enriched in the metabolic process. RT2 glucose-metabolism PCR Array showed the expression of genes associated with glycolysis. The results of western blotting showed that the level of histone Kla was increased in macrophages. The results of immunofluorescence and ELISA showed that Aβ levels in macrophages and culture medium were increased after transfection. CONCLUSION The present study revealed that msRNA P.G_45033 can induce Aβ production by enhancing glycolysis and histone Kla in macrophages.
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Affiliation(s)
- Yonghuan Zhang
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Yangyang Sun
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Ying Hu
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Shaowen Zheng
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Haigang Shao
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Li Lin
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China
| | - Yaping Pan
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China.
| | - Chen Li
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, Liaoning, China; Liaoning Provincial Key Laboratory of Oral Disease, Shenyang, Liaoning, China.
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López-Villodres JA, Escamilla A, Mercado-Sáenz S, Alba-Tercedor C, Rodriguez-Perez LM, Arranz-Salas I, Sanchez-Varo R, Bermúdez D. Microbiome Alterations and Alzheimer's Disease: Modeling Strategies with Transgenic Mice. Biomedicines 2023; 11:1846. [PMID: 37509487 PMCID: PMC10377071 DOI: 10.3390/biomedicines11071846] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
In the last decade, the role of the microbiota-gut-brain axis has been gaining momentum in the context of many neurodegenerative and metabolic disorders, including Alzheimer's disease (AD) and diabetes, respectively. Notably, a balanced gut microbiota contributes to the epithelial intestinal barrier maintenance, modulates the host immune system, and releases neurotransmitters and/or neuroprotective short-chain fatty acids. However, dysbiosis may provoke immune dysregulation, impacting neuroinflammation through peripheral-central immune communication. Moreover, lipopolysaccharide or detrimental microbial end-products can cross the blood-brain barrier and induce or at least potentiate the neuropathological progression of AD. Thus, after repeated failure to find a cure for this dementia, a necessary paradigmatic shift towards considering AD as a systemic disorder has occurred. Here, we present an overview of the use of germ-free and/or transgenic animal models as valid tools to unravel the connection between dysbiosis, metabolic diseases, and AD, and to investigate novel therapeutical targets. Given the high impact of dietary habits, not only on the microbiota but also on other well-established AD risk factors such as diabetes or obesity, consistent changes of lifestyle along with microbiome-based therapies should be considered as complementary approaches.
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Affiliation(s)
- Juan Antonio López-Villodres
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
| | - Alejandro Escamilla
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
- Instituto de Investigacion Biomedica de Malaga-IBIMA-Plataforma Bionand, 29071 Malaga, Spain
| | - Silvia Mercado-Sáenz
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
| | - Carmen Alba-Tercedor
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
| | - Luis Manuel Rodriguez-Perez
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
- Instituto de Investigacion Biomedica de Malaga-IBIMA-Plataforma Bionand, 29071 Malaga, Spain
| | - Isabel Arranz-Salas
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
- Instituto de Investigacion Biomedica de Malaga-IBIMA-Plataforma Bionand, 29071 Malaga, Spain
- Unidad de Anatomia Patologica, Hospital Universitario Virgen de la Victoria, 29010 Malaga, Spain
| | - Raquel Sanchez-Varo
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
- Instituto de Investigacion Biomedica de Malaga-IBIMA-Plataforma Bionand, 29071 Malaga, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
| | - Diego Bermúdez
- Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Malaga, 29071 Malaga, Spain
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12
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Weber C, Dilthey A, Finzer P. The role of microbiome-host interactions in the development of Alzheimer´s disease. Front Cell Infect Microbiol 2023; 13:1151021. [PMID: 37333848 PMCID: PMC10272569 DOI: 10.3389/fcimb.2023.1151021] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023] Open
Abstract
Alzheimer`s disease (AD) is the most prevalent cause of dementia. It is often assumed that AD is caused by an aggregation of extracellular beta-amyloid and intracellular tau-protein, supported by a recent study showing reduced brain amyloid levels and reduced cognitive decline under treatment with a beta-amyloid-binding antibody. Confirmation of the importance of amyloid as a therapeutic target notwithstanding, the underlying causes of beta-amyloid aggregation in the human brain, however, remain to be elucidated. Multiple lines of evidence point towards an important role of infectious agents and/or inflammatory conditions in the etiology of AD. Various microorganisms have been detected in the cerebrospinal fluid and brains of AD-patients and have thus been hypothesized to be linked to the development of AD, including Porphyromonas gingivalis (PG) and Spirochaetes. Intriguingly, these microorganisms are also found in the oral cavity under normal physiological conditions, which is often affected by multiple pathologies like caries or tooth loss in AD patients. Oral cavity pathologies are mostly accompanied by a compositional shift in the community of oral microbiota, mainly affecting commensal microorganisms and referred to as 'dysbiosis'. Oral dysbiosis seems to be at least partly mediated by key pathogens such as PG, and it is associated with a pro-inflammatory state that promotes the destruction of connective tissue in the mouth, possibly enabling the translocation of pathogenic microbiota from the oral cavity to the nervous system. It has therefore been hypothesized that dysbiosis of the oral microbiome may contribute to the development of AD. In this review, we discuss the infectious hypothesis of AD in the light of the oral microbiome and microbiome-host interactions, which may contribute to or even cause the development of AD. We discuss technical challenges relating to the detection of microorganisms in relevant body fluids and approaches for avoiding false-positives, and introduce the antibacterial protein lactoferrin as a potential link between the dysbiotic microbiome and the host inflammatory reaction.
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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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Cheng X, Chi L, Lin T, Liang F, Pei Z, Sun J, Teng W. Exogenous monocyte myeloid-derived suppressor cells ameliorate immune imbalance, neuroinflammation and cognitive impairment in 5xFAD mice infected with Porphyromonas gingivalis. J Neuroinflammation 2023; 20:55. [PMID: 36864466 PMCID: PMC9979576 DOI: 10.1186/s12974-023-02743-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/21/2023] [Indexed: 03/04/2023] Open
Abstract
BACKGROUND Periodontitis is closely associated with the pathogenesis of Alzheimer's disease (AD). Porphyromonas gingivalis (Pg), the keystone periodontal pathogen, has been reported in our recent study to cause immune-overreaction and induce cognitive impairment. Monocytic myeloid-derived suppressor cells (mMDSCs) possess potent immunosuppressive function. It is unclear whether mMDSCs-mediated immune homeostasis is impaired in AD patients with periodontitis, and whether exogenous mMDSCs could ameliorate immune-overreaction and cognitive impairment induced by Pg. METHODS To explore the influence of Pg on cognitive function, neuropathology and immune balance in vivo, 5xFAD mice were treated with live Pg by oral gavage, three times a week for 1 month. The cells of peripheral blood, spleen and bone marrow from 5xFAD mice were treated with Pg to detect the proportional and functional alterations of mMDSCs in vitro. Next, exogenous mMDSCs were sorted from wild-type healthy mice and intravenously injected into 5xFAD mice that were infected with Pg. We used behavioral tests, flow cytometry and immunofluorescent staining to evaluate whether exogenous mMDSCs could ameliorate the cognitive function, immune homeostasis and reduce neuropathology exacerbated by Pg infection. RESULTS Pg exacerbated cognitive impairment in 5xFAD mice, with the deposition of amyloid plaque and increased number of microglia in the hippocampus and cortex region. The proportion of mMDSCs decreased in Pg-treated mice. In addition, Pg reduced the proportion and the immunosuppressive function of mMDSCs in vitro. Supplement of exogenous mMDSCs improved the cognitive function, and enhanced the proportions of mMDSCs and IL-10+ T cells of 5xFAD mice infected with Pg. At the same time, supplement of exogenous mMDSCs increased the immunosuppressive function of endogenous mMDSCs while decreased the proportions of IL-6+ T cells and IFN-γ+ CD4+ T cells. In addition, the deposition of amyloid plaque decreased while the number of neurons increased in the hippocampus and cortex region after the supplement of exogenous mMDSCs. Furthermore, the number of microglia increased with an increase in the proportion of M2 phenotype. CONCLUSIONS Pg can reduce the proportion of mMDSCs, induce immune-overreaction, and exacerbate the neuroinflammation and cognitive impairment in 5xFAD mice. Supplement of exogenous mMDSCs can reduce the neuroinflammation, immune imbalance and cognitive impairment in 5xFAD mice infected with Pg. These findings indicate the mechanism of AD pathogenesis and Pg-mediated promotion of AD, and provide a potential therapeutic strategy for AD patients.
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Affiliation(s)
- Xiao Cheng
- grid.12981.330000 0001 2360 039XHospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Li Chi
- grid.12981.330000 0001 2360 039XHospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Tianqiong Lin
- grid.410560.60000 0004 1760 3078Dongguan Key Laboratory of Chronic Inflammatory Diseases, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan, China
| | - Fengyin Liang
- grid.12981.330000 0001 2360 039XDepartment of Neurology, The First Affiliated Hospital, Sun Yat-Sen University; Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases; National Key Clinical Department and Key Discipline of Neurology, No.58 Zhongshan Road2, Guangzhou, 510080 China
| | - Zhong Pei
- grid.12981.330000 0001 2360 039XDepartment of Neurology, The First Affiliated Hospital, Sun Yat-Sen University; Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases; National Key Clinical Department and Key Discipline of Neurology, No.58 Zhongshan Road2, Guangzhou, 510080 China
| | - Jianbo Sun
- Dongguan Key Laboratory of Chronic Inflammatory Diseases, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan, China.
| | - Wei Teng
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China.
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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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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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Dziedzic A. Is Periodontitis Associated with Age-Related Cognitive Impairment? The Systematic Review, Confounders Assessment and Meta-Analysis of Clinical Studies. Int J Mol Sci 2022; 23:15320. [PMID: 36499656 PMCID: PMC9739281 DOI: 10.3390/ijms232315320] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/27/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
It has been suggested that molecular pathological mechanisms responsible for periodontitis can be linked with biochemical alterations in neurodegenerative disorders. Hypothetically, chronic systemic inflammation as a response to periodontitis plays a role in the etiology of cognitive impairment. This study aimed to determine whether periodontitis (PDS) is a risk factor for age-related cognitive impairment (ACI) based on evidence of clinical studies. A comprehensive, structured systematic review of existing data adhering to the Preferred Reporting Items for Systematic Review and Meta Analyses (PRISMA) guidelines was carried out. Five electronic databases, PubMed, Embase, Scopus, Web of Science, and Cochrane, were searched for key terms published in peer-reviewed journals until January 2021. The Newcastle-Ottawa scale was used to assess the quality of studies and risk of bias. The primary and residual confounders were explored and evaluated. A meta-analysis synthesizing quantitative data was carried out using a random-effects model. Seventeen clinical studies were identified, including 14 cohort, one cross-sectional, and two case-control studies. Study samples ranged from 85 to 262,349 subjects, with follow-up between 2 and 32 years, and age above 45 years, except for two studies. The findings of studies suggesting the PDS-ACI relationship revealed substantial differences in design and methods. A noticeable variation related to the treatment of confounders was observed. Quality assessment unveiled a moderate quality of evidence and risk of bias. The subgroups meta-analysis and pooled sensitivity analysis of results from seven eligible studies demonstrated overall that the presence of PDS is associated with an increased risk of incidence of cognitive impairment (OR = 1.36, 95% CI 1.03-1.79), particularly dementia (OR = 1.39, 95% CI 1.02-1.88) and Alzheimer's disease (OR = 1.03 95% CI 0.98-1.07)). However, a considerable heterogeneity of synthesized data (I2 = 96%) and potential publication bias might affect obtained results. While there is a moderate statistical association between periodontitis and dementia, as well as Alzheimer's disease, the risk of bias in the evidence prevents conclusions being drawn about the role of periodontitis as a risk factor for age-related cognitive impairment.
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Affiliation(s)
- Arkadiusz Dziedzic
- Department of Conservative Dentistry with Endodontics, Medical University of Silesia, 40-055 Katowice, Poland
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18
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Inoue E, Minatozaki S, Katsuta Y, Nonaka S, Nakanishi H. Human β-Defensin 3 Inhibits Porphyromonas Gingivalis Lipopolysaccharide-Induced Oxidative and Inflammatory Responses of Microglia by Suppression of Cathepsins B and L. Int J Mol Sci 2022; 23:ijms232315099. [PMID: 36499428 PMCID: PMC9738813 DOI: 10.3390/ijms232315099] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
Recently, the effects of antibacterial peptides are suggested to have therapeutic potential in Alzheimer's disease. Furthermore, systemic treatment of Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) induced Alzheimer's disease-like neuropathological changes in middle-aged mice. Then, we examined whether human β-defensins (hBDs), antimicrobial peptides produced by the oral mucosa and salivary glands, can suppress Pg LPS-induced oxidative and inflammatory responses by microglia. hBD3 (1 μM) significantly suppressed Pg LPS-induced production of nitric oxide and interleukin-6 (IL-6) by MG6 cells, a mouse microglial cell line. hBD3 (1 μM) also significantly inhibited Pg LPS-induced expression of IL-6 by HMC3 cells, a human microglial cell line. In contrast, neither hBD1, hBD2 nor hBD4 failed to inhibit their productions. Furthermore, hBD3 suppressed Pg LPS-induced p65 nuclear translocation through the IκBα degradation. Pg LPS-induced expression of IL-6 was significantly suppressed by E64d, a cysteine protease inhibitor, and CA-074Me, a known specific inhibitor for cathepsin B, but not by pepstatin A, an aspartic protease inhibitor. Interestingly, hBD3 significantly inhibited enzymatic activities of recombinant human cathepsins B and L, lysosomal cysteine proteases, and their intracellular activities in MG6 cells. Therefore, hBD3 suppressed oxidative and inflammatory responses of microglia through the inhibition of cathepsins B and L, which enzymatic activities are necessary for the NF-κB activation.
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Affiliation(s)
- Erika Inoue
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Shiyo Minatozaki
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Yui Katsuta
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
- Correspondence:
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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: 3] [Impact Index Per Article: 1.5] [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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Ganz T, Fainstein N, Ben-Hur T. When the infectious environment meets the AD brain. Mol Neurodegener 2022; 17:53. [PMID: 35986296 PMCID: PMC9388962 DOI: 10.1186/s13024-022-00559-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022] Open
Abstract
Background The Amyloid theory of Alzheimer’s disease (AD) suggests that the deposition of Amyloid β (Aβ) in the brain triggers a chain of events, involving the deposition of phosphorylated Tau and other misfolded proteins, leading to neurodegeneration via neuroinflammation, oxidative stress, and neurovascular factors. The infectious theory linked various infectious agents with the development of AD, raising the possibility that they serve as etiological causes of the disease. Are these theories mutually exclusive, or do they coincide? Main body In this review, we will discuss how the two theories converge. We present a model by which (1) the systemic infectious burden accelerates the development of AD brain pathology via bacterial Amyloids and other pathogen-associated molecular patterns (PAMPs), and (2) the developing AD brain pathology increases its susceptibility to the neurotoxicity of infectious agents -derived PAMPs, which drive neurodegeneration via activated microglia. Conclusions The reciprocal effects of amyloid deposition and systemic infectious burden may lead to a vicious cycle fueling Alzheimer’s disease pathogenesis.
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Gong T, Chen Q, Mao H, Zhang Y, Ren H, Xu M, Chen H, Yang D. Outer membrane vesicles of Porphyromonas gingivalis trigger NLRP3 inflammasome and induce neuroinflammation, tau phosphorylation, and memory dysfunction in mice. Front Cell Infect Microbiol 2022; 12:925435. [PMID: 36017373 PMCID: PMC9397999 DOI: 10.3389/fcimb.2022.925435] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundPorphyromonas gingivalis (Pg), the keystone pathogen in chronic periodontitis, is reported to initiate Alzheimer’s disease pathologies in preclinical studies. However, the specific mechanisms and signaling pathways acting on the brain still need to be further explored. Outer membrane vesicles are derived from Gram-negative bacteria and contain many virulence factors of bacteria. We hypothesized that outer membrane vesicles are an important weapon of Porphyromonas gingivalis to initiate Alzheimer’s disease pathologies.MethodsThe outer membrane vesicles of Porphyromonas gingivalis (Pg OMVs, 4 mg/kg) or saline were delivered to 14-month-old mice by oral gavage every other day for eight weeks. Behavioral alterations were assessed by the open field test, Morris water maze, and Y-maze test. Blood–brain barrier permeability, neuroinflammation, tau phosphorylation, and NLRP3 inflammasome-related protein were analyzed.ResultsPg OMVs impaired memory and learning ability of mice and decreased tight junction–related gene expression ZO-1, occludin, claudin-5, and occludin protein expression in the hippocampus. Pg OMVs could be detected in the hippocampus and cortex three days after oral gavage. Furthermore, Pg OMVs activated both astrocytes and microglia and elevated IL-1β, tau phosphorylation on the Thr231 site, and NLRP3 inflammasome–related protein expression in the hippocampus. In in vitro studies, Pg OMV (5 µg/ml) stimulation increased the mRNA and immunofluorescence of NLRP3 in BV2 microglia, which were significantly inhibited by the NLRP3 inhibitor MCC950. In contrast, the tau phosphorylation in N2a neurons was enhanced after treatment with conditioned media from Pg OMV-stimulated microglia, which was attenuated after pretreatment with MCC950.ConclusionsThese results indicate that Pg OMVs prompt memory dysfunction, neuroinflammation, and tau phosphorylation and trigger NLRP3 inflammasome in the brain of middle-aged mice. We propose that Pg OMVs play an important role in activating neuroinflammation in the AD-like pathology triggered by Porphyromonas gingivalis, and NLRP3 inflammasome activation is a possible mechanism.
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Affiliation(s)
- Ting Gong
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Qi Chen
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Hongchen Mao
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Yao Zhang
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Huan Ren
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Mengmeng Xu
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Hong Chen
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
| | - Deqin Yang
- Department of Endodontics, Stomatological Hospital of Chongqing Medical University, Chongqing, China
- Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, Chongqing, China
- Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing Medical University, Chongqing, China
- *Correspondence: Deqin Yang,
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22
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Jiang SJ, Xiao X, Zheng J, Lai S, Yang L, Li J, Liu C, Yang Y, Mu Y. Antibacterial and antibiofilm activities of novel antimicrobial peptide DP7 against the periodontal pathogen Porphyromonas gingivalis. J Appl Microbiol 2022; 133:1052-1062. [PMID: 35567537 DOI: 10.1111/jam.15614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 04/01/2022] [Accepted: 04/27/2022] [Indexed: 12/29/2022]
Abstract
AIMS Accumulating evidence suggests that Porphyromonas gingivalis is closely associated with the development of various chronic inflammatory diseases, particularly periodontitis. This study investigated the antibacterial activity and action mechanism of a novel antimicrobial peptide (AMP), DP7, against P. gingivalis. METHODS AND RESULTS The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for DP7 were determined via a broth microdilution method, revealing an MIC of 8 μg ml-1 and MBC of 32 μg ml-1 . Growth inhibition and killing assays confirmed the bactericidal effect of DP7, and treatment with DP7 at MBC eliminated P. gingivalis within 8 h. DP7 had a low cytotoxic effect against human cells. Transmission electron microscopy revealed that DP7 destroyed the bacterial membrane, and confocal laser scanning microscopy revealed its inhibitory effect on P. gingivalis biofilms. Quantitative reverse transcription-polymerase chain reaction revealed DP7-mediated inhibition of several virulence factor genes, partially explaining its antibacterial mechanism. CONCLUSIONS DP7, a novel AMP with low mammalian cytotoxicity, inhibits both planktonic and biofilm forms of P. gingivalis by destroying the bacterial membrane and reducing virulence factor gene expression. SIGNIFICANCE AND IMPACT OF THE STUDY DP7 has potential clinical application in the prevention and treatment of P. gingivalis-associated diseases.
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Affiliation(s)
- Si-Jing Jiang
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Xun Xiao
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Jiajun Zheng
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Shuang Lai
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Li Yang
- State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Jing Li
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Chang Liu
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Yiling Yang
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Yangdong Mu
- Stomatology Department, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
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23
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Lin J, Huang D, Xu H, Zhan F, Tan X. Macrophages: A communication network linking Porphyromonas gingivalis infection and associated systemic diseases. Front Immunol 2022; 13:952040. [PMID: 35967399 PMCID: PMC9363567 DOI: 10.3389/fimmu.2022.952040] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/30/2022] [Indexed: 12/03/2022] Open
Abstract
Porphyromonas gingivalis (P. gingivalis) is a Gram-negative anaerobic pathogen that is involved in the pathogenesis of periodontitis and systemic diseases. P. gingivalis has recently been detected in rheumatoid arthritis (RA), cardiovascular disease, and tumors, as well as Alzheimer’s disease (AD), and the presence of P. gingivalis in these diseases are correlated with poor prognosis. Macrophages are major innate immune cells which modulate immune responses against pathogens, however, multiple bacteria have evolved abilities to evade or even subvert the macrophages’ immune response, in which subsequently promote the diseases’ initiation and progression. P. gingivalis as a keystone pathogen of periodontitis has received increasing attention for the onset and development of systemic diseases. P. gingivalis induces macrophage polarization and inflammasome activation. It also causes immune response evasion which plays important roles in promoting inflammatory diseases, autoimmune diseases, and tumor development. In this review, we summarize recent discoveries on the interaction of P. gingivalis and macrophages in relevant disease development and progression, such as periodontitis, atherosclerosis, RA, AD, and cancers, aiming to provide an in-depth mechanistic understanding of this interaction and potential therapeutic strategies.
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Affiliation(s)
- Jie Lin
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases and Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Dingming Huang
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases and Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hongwei Xu
- Myeloma Center, Winthrop P. Rockefeller Cancer Institute, Department of Internal Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR, United States
| | - Fenghuang Zhan
- Myeloma Center, Winthrop P. Rockefeller Cancer Institute, Department of Internal Medicine, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR, United States
- Division of Hematology and Oncology, Department of Internal Medicine, University of Iowa, Iowa, IA, United States
- *Correspondence: XueLian Tan, ; Fenghuang Zhan,
| | - XueLian Tan
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases and Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- *Correspondence: XueLian Tan, ; Fenghuang Zhan,
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24
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Li D, Ren T, Li H, Liao G, Zhang X. Porphyromonas gingivalis: A key role in Parkinson's disease with cognitive impairment? Front Neurol 2022; 13:945523. [PMID: 35959396 PMCID: PMC9363011 DOI: 10.3389/fneur.2022.945523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/04/2022] [Indexed: 11/15/2022] Open
Abstract
Cognitive impairment (CI) is a common complication of Parkinson's disease (PD). The major features of Parkinson's disease with cognitive impairment (PD-CI) include convergence of α-Synuclein (α-Syn) and Alzheimer's disease (AD)-like pathologies, neuroinflammation, and dysbiosis of gut microbiota. Porphyromonas gingivalis (P. gingivalis) is an important pathogen in periodontitis. Recent research has suggested a role of P. gingivalis and its virulence factor in the pathogenesis of PD and AD, in particular concerning neuroinflammation and deposition of α-Synuclein (α-Syn) and amyloid-β (Aβ). Furthermore, in animal models, oral P. gingivalis could cause neurodegeneration through regulating the gut-brain axis, suggesting an oral-gut-brain axis might exist. In this article, we discussed the pathological characteristics of PD-CI and the role of P. gingivalis in them.
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Affiliation(s)
- Dongcheng Li
- Department of Neurology, Affiliated Maoming People's Hospital, Southern Medical University, Maoming, China
| | - Tengzhu Ren
- Department of Neurology, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Hao Li
- Department of Neurology, Affiliated Maoming People's Hospital, Southern Medical University, Maoming, China
| | - Geng Liao
- Department of Neurology, Affiliated Maoming People's Hospital, Southern Medical University, Maoming, China
| | - Xiong Zhang
- Department of Neurology, Affiliated Maoming People's Hospital, Southern Medical University, Maoming, China
- *Correspondence: Xiong Zhang
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25
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Harding A, Kanagasingam S, Welbury R, Singhrao SK. Periodontitis as a Risk Factor for Alzheimer's Disease: The Experimental Journey So Far, with Hope of Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1373:241-260. [PMID: 35612802 DOI: 10.1007/978-3-030-96881-6_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Periodontitis and Alzheimer's disease (AD) exist globally within the adult population. Given that the risk of AD incidence doubles within 10 years from the time of periodontal disease diagnosis, there is a window of opportunity for slowing down or preventing AD by risk-reduction-based intervention. Literature appraisal on the shared risk factors of these diseases suggests a shift to a healthy lifestyle would be beneficial. Generalised (chronic) periodontitis with an established dysbiotic polymicrobial aetiology affects the tooth supporting tissues with eventual tooth loss. The cause of AD remains unknown, however two neurohistopathological lesions - amyloid-beta plaques and neurofibrillary tangles, together with the clinical history, provide AD diagnosis at autopsy. Historically, prominence was given to the two hallmark lesions but now emphasis is placed on cerebral inflammation and what triggers it. Low socioeconomic status promotes poor lifestyles that compromise oral and personal hygiene along with reliance on poor dietary intake. Taken together with advancing age and a declining immune protection, these risk factors may negatively impact on periodontitis and AD. These factors also provide a tangible solution to controlling pathogenic bacteria indigenous to the oral and gastrointestinal tract microbioes in vulnerable subjects. The focus here is on Porphyromonas gingivalis, one of several important bacterial pathogens associated with both periodontitis and AD. Recent research has enabled advances in our knowledge of the armoury of P. gingivalis via reproduction of all clinical and neuropathological hallmark lesions of AD and chronic periodontal disease in vitro and in vivo experimental models, thus paving the way for better future management.
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Affiliation(s)
- Alice Harding
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Shalini Kanagasingam
- Brain and Behavior Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, 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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26
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Cirstea MS, Kliger D, MacLellan AD, Yu AC, Langlois J, Fan M, Boroomand S, Kharazyan F, Hsiung RGY, MacVicar BA, Chertkow H, Whitehead V, Finlay B, Appel-Cresswell S. The Oral and Fecal Microbiota in a Canadian Cohort of Alzheimer's Disease. J Alzheimers Dis 2022; 87:247-258. [PMID: 35275538 DOI: 10.3233/jad-215520] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Despite decades of research, our understanding of Alzheimer's disease (AD) etiology remains incomplete. In recent years, appreciation has grown for potential roles for the microbiota in shaping neurological health. OBJECTIVE This study aimed to examine associations between the microbiota and AD in a human cross-sectional cohort. METHODS Forty-five AD patients and 54 matched controls were recruited in Vancouver, Canada. Fecal and oral samples underwent 16S microbiota sequencing. A wide array of demographic and clinical data were collected. Differences between participant groups were assessed, and associations between microbes and clinical variables were examined within the AD population. RESULTS The gut microbiota of AD patients displayed lower diversity relative to controls, although taxonomic differences were sparse. In contrast, the AD oral microbiota displayed higher diversity, with several taxonomic differences relative to controls, including a lower abundance of the families Streptococcaceae and Actinomycetaceae, and a higher abundance of Weeksellaceae, among others. The periodontitis-associated oral microbe Porphyromonas gingivalis was 5 times more prevalent among patients. No significant associations between gut or oral microbes and cognition were detected, but several correlations existed between microbes and mood disorders and BMI among patients, including a strong positive correlation between Alphaproteobacteria and depression score. CONCLUSION The gut microbiota of AD patients was not overtly different from controls, although it displayed lower diversity, an overall marker of microbiota health. The oral microbiota did display marked differences. Cognition was not associated with a microbial signature, but other relevant AD factors including mood and BMI did demonstrate an association.
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Affiliation(s)
- Mihai S Cirstea
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Pacific Parkinson's Research Centre, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Kliger
- Pacific Parkinson's Research Centre, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Clinic for Alzheimer Disease and Related Disorders, University of British Columbia, Vancouver, BC, Canada
| | - Abbey D MacLellan
- Pacific Parkinson's Research Centre, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Adam C Yu
- Pacific Parkinson's Research Centre, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Jenna Langlois
- Pacific Parkinson's Research Centre, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Clinic for Alzheimer Disease and Related Disorders, University of British Columbia, Vancouver, BC, Canada
| | - Mannie Fan
- Clinic for Alzheimer Disease and Related Disorders, University of British Columbia, Vancouver, BC, Canada
| | - Seti Boroomand
- Borgland Family Brain Tissue and DNA Bank, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Faezeh Kharazyan
- Borgland Family Brain Tissue and DNA Bank, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Robyn G Y Hsiung
- Clinic for Alzheimer Disease and Related Disorders, University of British Columbia, Vancouver, BC, Canada.,Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Brian A MacVicar
- Department of Psychiatry, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Howard Chertkow
- Baycrest and Rotman Research Institute, Toronto, Ontario, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Victor Whitehead
- Lady Davis Institute for Medical Research, McGill University, Montreal, Quebec, Canada
| | - Brett Finlay
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Department of Biochemistry, University of British Columbia, Vancouver, BC, Canada
| | - Silke Appel-Cresswell
- Pacific Parkinson's Research Centre, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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27
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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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28
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Xie J, Van Hoecke L, Vandenbroucke RE. The Impact of Systemic Inflammation on Alzheimer's Disease Pathology. Front Immunol 2022; 12:796867. [PMID: 35069578 PMCID: PMC8770958 DOI: 10.3389/fimmu.2021.796867] [Citation(s) in RCA: 79] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is a devastating age-related neurodegenerative disorder with an alarming increasing prevalence. Except for the recently FDA-approved Aducanumab of which the therapeutic effect is not yet conclusively proven, only symptomatic medication that is effective for some AD patients is available. In order to be able to design more rational and effective treatments, our understanding of the mechanisms behind the pathogenesis and progression of AD urgently needs to be improved. Over the last years, it became increasingly clear that peripheral inflammation is one of the detrimental factors that can contribute to the disease. Here, we discuss the current understanding of how systemic and intestinal (referred to as the gut-brain axis) inflammatory processes may affect brain pathology, with a specific focus on AD. Moreover, we give a comprehensive overview of the different preclinical as well as clinical studies that link peripheral Inflammation to AD initiation and progression. Altogether, this review broadens our understanding of the mechanisms behind AD pathology and may help in the rational design of further research aiming to identify novel therapeutic targets.
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Affiliation(s)
- Junhua Xie
- VIB Center for Inflammation Research, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Lien Van Hoecke
- VIB Center for Inflammation Research, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Roosmarijn E Vandenbroucke
- VIB Center for Inflammation Research, VIB, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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29
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Zhang J, Xie M, Huang X, Chen G, Yin Y, Lu X, Feng G, Yu R, Chen L. The Effects of Porphyromonas gingivalis on Atherosclerosis-Related Cells. Front Immunol 2022; 12:766560. [PMID: 35003080 PMCID: PMC8734595 DOI: 10.3389/fimmu.2021.766560] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/30/2021] [Indexed: 12/21/2022] Open
Abstract
Atherosclerosis (AS), one of the most common types of cardiovascular disease, has initially been attributed to the accumulation of fats and fibrous materials. However, more and more researchers regarded it as a chronic inflammatory disease nowadays. Infective disease, such as periodontitis, is related to the risk of atherosclerosis. Porphyromonas gingivalis (P. gingivalis), one of the most common bacteria in stomatology, is usually discovered in atherosclerotic plaque in patients. Furthermore, it was reported that P. gingivalis can promote the progression of atherosclerosis. Elucidating the underlying mechanisms of P. gingivalis in atherosclerosis attracted attention, which is thought to be crucial to the therapy of atherosclerosis. Nevertheless, the pathogenesis of atherosclerosis is much complicated, and many kinds of cells participate in it. By summarizing existing studies, we find that P. gingivalis can influence the function of many cells in atherosclerosis. It can induce the dysfunction of endothelium, promote the formation of foam cells as well as the proliferation and calcification of vascular smooth muscle cells, and lead to the imbalance of regulatory T cells (Tregs) and T helper (Th) cells, ultimately promoting the occurrence and development of atherosclerosis. This article summarizes the specific mechanism of atherosclerosis caused by P. gingivalis. It sorts out the interaction between P. gingivalis and AS-related cells, which provides a new perspective for us to prevent or slow down the occurrence and development of AS by inhibiting periodontal pathogens.
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Affiliation(s)
- Jiaqi Zhang
- 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
| | - Mengru Xie
- 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
| | - Xiaofei Huang
- 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
| | - Guangjin Chen
- 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
| | - Ying Yin
- 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
| | - Xiaofeng Lu
- 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
| | - Guangxia Feng
- 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
| | - Lili Chen
- 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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Chi L, Cheng X, Lin L, Yang T, Sun J, Feng Y, Liang F, Pei Z, Teng W. Porphyromonas gingivalis-Induced Cognitive Impairment Is Associated With Gut Dysbiosis, Neuroinflammation, and Glymphatic Dysfunction. Front Cell Infect Microbiol 2021; 11:755925. [PMID: 34926316 PMCID: PMC8672439 DOI: 10.3389/fcimb.2021.755925] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/22/2021] [Indexed: 12/20/2022] Open
Abstract
Background Periodontal pathogen and gut microbiota are closely associated with the pathogenesis of Alzheimer's disease (AD). Porphyromonas gingivalis (Pg), the keystone periodontal pathogen, can induce cognitive impairment. The gut has a connection and communication with the brain, which is an important aspect of the gut-brain axis (GBA). In the present study, we investigate whether Pg induces cognitive impairment through disturbing the GBA. Methods In this study, Pg was orally administered to mice, three times a week for 1 month. The effects of Pg administration on the gut and brain were evaluated through behaviors, gut microbiota, immune cells, glymphatic pathway clearance, and neuroinflammation. Results Pg induced cognitive impairment and dysbiosis of gut microbiota. The α-diversity parameters did not show significant change after Pg administration. The β-diversity demonstrated that the gut microbiota compositions were different between the Pg-administered and control groups. At the species level, the Pg group displayed a lower abundance of Parabacteroides gordonii and Ruminococcus callidus than the control group, but a higher abundance of Mucispirillum schaedleri. The proportions of lymphocytes in the periphery and myeloid cells infiltrating the brain were increased in Pg-treated animals. In addition, the solute clearance efficiency of the glymphatic system decreased. Neurons in the hippocampus and cortex regions were reduced in mice treated with Pg. Microglia, astrocytes, and apoptotic cells were increased. Furthermore, amyloid plaque appeared in the hippocampus and cortex regions in Pg-treated mice. Conclusions These findings indicate that Pg may play an important role in gut dysbiosis, neuroinflammation, and glymphatic system impairment, which may in turn lead to cognitive impairment.
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Affiliation(s)
- Li Chi
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Xiao Cheng
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Lishan Lin
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Tao Yang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Jianbo Sun
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Yiwei Feng
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Fengyin Liang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Zhong Pei
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Wei Teng
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
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Kouki MA, Pritchard AB, Alder JE, Crean S. Do Periodontal Pathogens or Associated Virulence Factors Have a Deleterious Effect on the Blood-Brain Barrier, Contributing to Alzheimer's Disease? J Alzheimers Dis 2021; 85:957-973. [PMID: 34897087 DOI: 10.3233/jad-215103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The central nervous system (CNS) is protected by a highly selective barrier, the blood-brain barrier (BBB), that regulates the exchange and homeostasis of bloodborne molecules, excluding xenobiotics. This barrier forms the first line of defense by prohibiting pathogens from crossing to the CNS. Aging and chronic exposure of the BBB to pathogens renders it permeable, and this may give rise to pathology in the CNS such as Alzheimer's disease (AD). Researchers have linked pathogens associated with periodontitis to neuroinflammation and AD-like pathology in vivo and in vitro. Although the presence of periodontitis-associated bacteria has been linked to AD in several clinical studies as DNA and virulence factors were confirmed in brain samples of human AD subjects, the mechanism by which the bacteria traverse to the brain and potentially influences neuropathology is unknown. In this review, we present current knowledge about the association between periodontitis and AD, the mechanism whereby periodontal pathogens might provoke neuroinflammation and how periodontal pathogens could affect the BBB. We suggest future studies, with emphasis on the use of human in vitro models of cells associated with the BBB to unravel the pathway of entry for these bacteria to the CNS and to reveal the molecular and cellular pathways involved in initiating the AD-like pathology. In conclusion, evidence demonstrate that bacteria associated with periodontitis and their virulence factors are capable of inflecting damage to the BBB and have a role in giving rise to pathology similar to that found in AD.
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Affiliation(s)
- Mhd Ammar Kouki
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Anna Barlach Pritchard
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston, UK
| | - Jane Elizabeth Alder
- Brain and Behaviour Centre, Faculty of Clinical and Biomedical Sciences, School of Pharmacy and Biomedical Sciences, 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
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32
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Olsen I. Porphyromonas gingivalis-Induced Neuroinflammation in Alzheimer's Disease. Front Neurosci 2021; 15:691016. [PMID: 34720846 PMCID: PMC8551391 DOI: 10.3389/fnins.2021.691016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
"Chronic" periodontitis and its keystone pathogen Porphyromonas gingivalis have repeatedly been associated with Alzheimer's disease (AD). Pathological hallmarks in AD are brain accumulations of amyloid-beta and neurofibrillary tangles consisting of aggregated and hyperphosphorylated tau. In addition, neuroinflammation induced by P. gingivalis has increasingly been recognized as a factor in the pathogenesis of AD. The present mini-review discusses possible mechanisms for the induction of neuroinflammation by P. gingivalis in AD, involving factors such as pro-inflammatory mediators, amyloid-beta, tau, microglia, cathepsin B, and protein kinase R. Inflammagens of P. gingivalis such as lipopolysaccharide and gingipains are also discussed.
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Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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33
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Qi X, Zhu Z, Plassman BL, Wu B. Dose-Response Meta-Analysis on Tooth Loss With the Risk of Cognitive Impairment and Dementia. J Am Med Dir Assoc 2021; 22:2039-2045. [PMID: 34579934 PMCID: PMC8479246 DOI: 10.1016/j.jamda.2021.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To quantify the dose-response associations between tooth loss and risk of cognitive impairment and dementia. DESIGN Longitudinal studies that examined the association between tooth loss and cognitive function were systematically searched on 6 databases through March 1, 2020. The study adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Risk estimates were pooled using random-effects models. The dose-response associations were assessed using generalized least squares spline models. SETTING AND PARTICIPANTS Adults from community, institution, outpatient or in-hospital were included in the meta-analysis. MEASURES Cognitive impairment and dementia were defined by neuropsychological tests, diagnostic criteria, or medical records. Tooth loss was self-reported or assessed by clinical examinations. RESULTS Fourteen studies were entered into the meta-analysis, including 34,074 participants and 4689 cases with diminished cognitive function. Participants with more tooth loss had a 1.48 times higher risk of developing cognitive impairment [95% confidence interval (CI) 1.18-1.87] and 1.28 times higher risk of being diagnosed with dementia (95% CI 1.09-1.49); however, the association was nonsignificant for participants using dentures (relative risk = 1.10, 95% CI 0.90-1.11). Eight studies were included in the dose-response analysis, and data supported the use of linear models. Each additional tooth loss was associated with a 0.014 increased relative risk of cognitive impairment and 0.011 elevated relative risks of dementia. Edentulous participants faced a 1.54 times higher risk of cognitive impairment and a 1.40 times higher risk of being diagnosed with dementia. CONCLUSIONS AND IMPLICATIONS Moderate-quality evidence suggested tooth loss was independently associated with cognitive impairment and dementia; risk of diminished cognitive function increased with incremental numbers of teeth lost. Furthermore, timely prosthodontic treatment with dentures may reduce the progression of cognitive decline related to tooth loss.
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Affiliation(s)
- Xiang Qi
- Rory Meyers College of Nursing, New York University, New York, NY, USA
| | - Zheng Zhu
- School of Nursing, Fudan University, Shanghai, China; Fudan University Centre for Evidence-based Nursing: A Joanna Briggs Institute Centre of Excellence, Shanghai, China
| | | | - Bei Wu
- Rory Meyers College of Nursing, New York University, New York, NY, USA; NYU Aging Incubator, New York University, New York, NY, USA.
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Okamura H, Hirota K, Yoshida K, Weng Y, He Y, Shiotsu N, Ikegame M, Uchida-Fukuhara Y, Tanai A, Guo J. Outer membrane vesicles of Porphyromonas gingivalis: Novel communication tool and strategy. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:138-146. [PMID: 34484474 PMCID: PMC8399048 DOI: 10.1016/j.jdsr.2021.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/09/2021] [Accepted: 07/18/2021] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) have been recognized as a universal method of cellular communications and are reportedly produced in bacteria, archaea, and eukaryotes. Bacterial EVs are often called “Outer Membrane Vesicles” (OMVs) as they were the result of a controlled blebbing of the outer membrane of gram-negative bacteria such as Porphyromonas gingivalis (P. gingivalis). Bacterial EVs are natural messengers, implicated in intra- and inter-species cell-to-cell communication among microorganism populations present in microbiota. Bacteria can incorporate their pathogens into OMVs; the content of OMVs differs, depending on the type of bacteria. The production of distinct types of OMVs can be mediated by different factors and routes. A recent study highlighted OMVs ability to carry crucial molecules implicated in immune modulation, and, nowadays, they are considered as a way to communicate and transfer messages from the bacteria to the host and vice versa. This review article focuses on the current understanding of OMVs produced from major oral bacteria, P. gingivalis: generation, characteristics, and contents as well as the involvement in signal transduction of host cells and systemic diseases. Our recent study regarding the action of P. gingivalis OMVs in the living body is also summarized.
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Affiliation(s)
- Hirohiko Okamura
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Katsuhiko Hirota
- Department of Medical Hygiene, Dental Hygiene Course, Kochi Gakuen College, Kochi 780-0955, Japan
| | - Kaya Yoshida
- Department of Oral Healthcare Education, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8504, Japan
| | - Yao Weng
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Yuhan He
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Noriko Shiotsu
- Comprehensive Dental Clinic, Okayama University Hospital, Okayama University, Okayama, Japan
| | - Mika Ikegame
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Yoko Uchida-Fukuhara
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Airi Tanai
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan
| | - Jiajie Guo
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kitaku, Okayama 770-8525, Japan.,Department of Endodontics, School of Stomatology, China Medical University, Nanjing North Street 117, Shenyang 110002, China
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35
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Huang W, Zeng F, Gu Y, Jiang M, Zhang X, Yan X, Kadowaki T, Mizutani S, Kashiwazaki H, Ni J, Wu Z. Porphyromonas Gingivalis Infection Induces Synaptic Failure via Increased IL-1β Production in Leptomeningeal Cells. J Alzheimers Dis 2021; 83:665-681. [PMID: 34334391 DOI: 10.3233/jad-210031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Studies have reported that synaptic failure occurs before the Alzheimer's disease (AD) onset. The systemic Porphyromonas gingivalis (P. gingivalis) infection is involved in memory decline. We previously showed that leptomeningeal cells, covering the brain, activate glial cells by releasing IL-1β in response to systemic inflammation. OBJECTIVE In the present study, we focused on the impact of leptomeningeal cells on neurons during systemic P. gingivalis infection. METHODS The responses of leptomeningeal cells and cortical neurons to systemic P. gingivalis infection were examined in 15-month-old mice. The mechanism of IL-1β production by P. gingivalis infected leptomeningeal cells was examined, and primary cortical neurons were treated with P. gingivalis infected leptomeningeal cells condition medium (Pg LCM). RESULTS Systemic P. gingivalis infection increased the expression of IL-1β in leptomeninges and reduced the synaptophysin (SYP) expression in leptomeninges proximity cortex in mice. Leptomeningeal cells phagocytosed P. gingivalis resulting in lysosomal rupture and Cathepsin B (CatB) leakage. Leaked CatB mediated NLRP3 inflammasome activation inducing IL-1β secretion in leptomeningeal cells. Pg LCM decreased the expression of synaptic molecules, including SYP, which was inhibited by an IL-1 receptor antagonist pre-treatment. CONCLUSION These observations demonstrate that P. gingivalis infection is involved in synaptic failure by inducing CatB/NLRP3 inflammasome-mediated IL-1β production in leptomeningeal cells. The periodontal bacteria-induced synaptic damage may accelerate the onset and cognitive decline of AD.
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Affiliation(s)
- Wanyi Huang
- Department of Aging Science and Pharmacology>, Faculty of Dental Science, Kyushu University, Fukuoka Japan
| | - Fan Zeng
- Department of Aging Science and Pharmacology>, Faculty of Dental Science, Kyushu University, Fukuoka Japan
| | - Yebo Gu
- Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Muzhou Jiang
- Department of Aging Science and Pharmacology>, Faculty of Dental Science, Kyushu University, Fukuoka Japan
| | - Xinwen Zhang
- Center of Implant Dentistry, School of Stomatology, China Medical University, Shenyang, China
| | - Xu Yan
- The VIP Department, School of Stomatology, China Medical University, Shenyang, China
| | - Tomoko Kadowaki
- Division of Frontier Life Science, Department of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Shinsuke Mizutani
- Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.,OBT Research Center, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
| | - Haruhiko Kashiwazaki
- Section of Geriatric Dentistry and Perioperative Medicine in Dentistry, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Haidian District, Beijing, China
| | - Zhou Wu
- Department of Aging Science and Pharmacology>, Faculty of Dental Science, Kyushu University, Fukuoka Japan.,OBT Research Center, Faculty of Dental Sciences, Kyushu University, Fukuoka, Japan
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36
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Shi M, Li C, Tian X, Chu F, Zhu J. Can Control Infections Slow Down the Progression of Alzheimer's Disease? Talking About the Role of Infections in Alzheimer's Disease. Front Aging Neurosci 2021; 13:685863. [PMID: 34366826 PMCID: PMC8339924 DOI: 10.3389/fnagi.2021.685863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/24/2021] [Indexed: 01/07/2023] Open
Abstract
Alzheimer’s disease as the most common age-related dementia affects more than 40 million people in the world, representing a global public health priority. However, the pathogenesis of Alzheimer’s disease (AD) is complex, and it remains unclear. Over the past decades, all efforts made in the treatments of AD, with targeting the pathogenic amyloid β (Aβ), neurofibrillary tangles, and misfolded tau protein, were failed. Recently, many studies have hinted that infection, and chronic inflammation that caused by infection are crucial risk factors for AD development and progress. In the review, we analyzed the role of infections caused by bacteria, viruses, and other pathogens in the pathogenesis of AD and its animal models, and explored the therapeutic possibility with anti-infections for AD. However, based on the published data, it is still difficult to determine their causal relationship between infection and AD due to contradictory results. We think that the role of infection in the pathogenesis of AD should not be ignored, even though infection does not necessarily cause AD, it may act as an accelerator in AD at least. It is essential to conduct the longitudinal studies and randomized controlled trials in humans, which can determine the role of infection in AD and clarify the links between infection and the pathological features of AD. Finding targeting infection drugs and identifying the time window for applying antibacterial or antiviral intervention may be more promising for future clinical therapeutic strategies in AD.
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Affiliation(s)
- Mingchao Shi
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Chunrong Li
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Xiaoping Tian
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital of Shenzhen University Medical College, Shenzhen, China
| | - Fengna Chu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Jie Zhu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Changchun, China.,Division of Neurogeriatrcs, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
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37
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Olsen I. Possible effects of Porphyromonas gingivalis on the blood-brain barrier in Alzheimer's disease. Expert Rev Anti Infect Ther 2021; 19:1367-1371. [PMID: 33938372 DOI: 10.1080/14787210.2021.1925540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway,
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38
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Narengaowa, Kong W, Lan F, Awan UF, Qing H, Ni J. The Oral-Gut-Brain AXIS: The Influence of Microbes in Alzheimer's Disease. Front Cell Neurosci 2021; 15:633735. [PMID: 33935651 PMCID: PMC8079629 DOI: 10.3389/fncel.2021.633735] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/18/2021] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most frequently diagnosed neurodegenerative disorders worldwide and poses a major challenge for both affected individuals and their caregivers. AD is a progressive neurological disorder associated with high rates of brain atrophy. Despite its durable influence on human health, understanding AD has been complicated by its enigmatic and multifactorial nature. Neurofibrillary tangles and the deposition of amyloid-beta (Aβ) protein are typical pathological features and fundamental causes of cognitive impairment in AD patients. Dysbiosis of oral and gut microbiota has been reported to induce and accelerate the formation of Aβ plaques and neurofibrillary tangles. For instance, some oral microbes can spread to the brain through cranial nerves or cellular infections, which has been suggested to increase the risk of developing AD. Importantly, the interaction between intestinal microbiota and brain cells has been recognized as influencing the development of AD as well as other neurodegenerative diseases. In particular, the metabolites produced by certain intestinal microorganisms can affect the activity of microglia and further mediate neuroinflammation, which is a leading cause of neuronal necrosis and AD pathogenesis. Which pathogens and associated pathways are involved in the development and progression of AD remains to be elucidated; however, it is well-known that gut microbiota and their metabolites can affect the brain by both direct and indirect means. Understanding the specific mechanisms involved in the interaction between these pathogens and the nervous system is vital for the early intervention in AD. In this review, we aim to comprehensively discuss the possible mechanistic pathways underlying the oral-brain, the gut-brain and the oral-gut-brain associations.
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Affiliation(s)
- Narengaowa
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Wei Kong
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Fei Lan
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Umer Farooq Awan
- Laboratory of Molecular Biology, Department of Botany, Government College University, Lahore, Pakistan
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, Beijing, China
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Sciences, Beijing Institute of Technology, Beijing, China
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39
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Chang AM, Kantrong N, Darveau RP. Maintaining homeostatic control of periodontal epithelial tissue. Periodontol 2000 2021; 86:188-200. [PMID: 33690934 DOI: 10.1111/prd.12369] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Years of coevolution with resident microbes has made them an essential component of health. Yet, little is known about oral commensal bacteria's contribution to and role in the maintenance of oral health and homeostasis. Commensal bacteria are speculated to play a host protective role in the maintenance of health. In this review, we describe and provide examples of the coordinate regulation that occurs between oral commensal bacteria and the host innate immune response to modulate and maintain oral homeostasis.
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Affiliation(s)
- Ana M Chang
- Department of Periodontics, University of Washington, Seattle, Washington, USA
| | - Nutthapong Kantrong
- Department of Periodontics, University of Washington, Seattle, Washington, USA.,Oral Biology Research Unit, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Richard P Darveau
- Department of Periodontics, University of Washington, Seattle, Washington, USA
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Ni J, Wu Z. Inflammation Spreading: Negative Spiral Linking Systemic Inflammatory Disorders and Alzheimer's Disease. Front Cell Neurosci 2021; 15:638686. [PMID: 33716675 PMCID: PMC7947253 DOI: 10.3389/fncel.2021.638686] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/03/2021] [Indexed: 12/15/2022] Open
Abstract
As a physiological response to injury in the internal body organs, inflammation is responsible for removing dangerous stimuli and initiating healing. However, persistent and exaggerative chronic inflammation causes undesirable negative effects in the organs. Inflammation occurring in the brain and spinal cord is known as neuroinflammation, with microglia acting as the central cellular player. There is increasing evidence suggesting that chronic neuroinflammation is the most relevant pathological feature of Alzheimer’s disease (AD), regulating other pathological features, such as the accumulation of amyloid-β (Aβ) and hyperphosphorylation of Tau. Systemic inflammatory signals caused by systemic disorders are known to strongly influence neuroinflammation as a consequence of microglial activation, inflammatory mediator production, and the recruitment of peripheral immune cells to the brain, resulting in neuronal dysfunction. However, the neuroinflammation-accelerated neuronal dysfunction in AD also influences the functions of peripheral organs. In the present review, we highlight the link between systemic inflammatory disorders and AD, with inflammation serving as the common explosion. We discuss the molecular mechanisms that govern the crosstalk between systemic inflammation and neuroinflammation. In our view, inflammation spreading indicates a negative spiral between systemic diseases and AD. Therefore, “dampening inflammation” through the inhibition of cathepsin (Cat)B or CatS may be a novel therapeutic approach for delaying the onset of and enacting early intervention for AD.
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Affiliation(s)
- Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhou Wu
- Department of Aging Science and Pharmacology, Faculty of Dental Science, Kyushu University, Fukuoka, Japan.,OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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41
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Olsen I. Porphyromonas Gingivalis May Seek the Alzheimer's Disease Brain to Acquire Iron from Its Surplus. J Alzheimers Dis Rep 2021; 5:79-86. [PMID: 33681719 PMCID: PMC7903007 DOI: 10.3233/adr-200272] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Iron accumulates in the brain of subjects with Alzheimer’s disease (AD). Here it promotes the aggregation of amyloid-β plaques in which it is abundant. Iron induces amyloid-β neurotoxicity by damaging free radicals and causing oxidative stress in brain areas with neurodegeneration. It can also bind to tau in AD and enhance the toxicity of tau through co-localization with neurofibrillary tangles and induce accumulation of these tangles. Porphyromonas gingivalis is a key oral pathogen in the widespread biofilm-induced disease “chronic” periodontitis, and recently, has been suggested to have an important role in the pathogenesis of AD. P. gingivalis has an obligate requirement for iron. The current paper suggests that P. gingivalis seeks the AD brain, where it has been identified, to satisfy this need. If this is correct, iron chelators binding iron could have beneficial effects in the treatment of AD. Indeed, studies from both animal AD models and humans with AD have indicated that iron chelators, e.g., lactoferrin, can have such effects. Lactoferrin can also inhibit P. gingivalis growth and proteinases and its ability to form biofilm.
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Affiliation(s)
- Ingar Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
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Relationship of Porphyromonas gingivalis and Alzheimer's disease: a systematic review of pre-clinical studies. Clin Oral Investig 2021; 25:797-806. [PMID: 33469718 DOI: 10.1007/s00784-020-03764-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVES This study aimed to analyze the following PICO question: Are animals infected with Porphyromonas gingivalis (P. gingivalis) or bacterial lipopolysaccharide (Pg-LPS) more affected by neurodegeneration, similar to the pathogenesis generated by Alzheimer's disease (AD), compared with non-infected animals? METHODS Databases PubMed, Lilacs, SciELO, Science Direct, Scopus, Web of Science, and Cochrane were searched for pre-clinical in vivo studies in which mice were infected with P. gingivalis or received Pg-LPS, in order to assess the brain tissue and cognitive impairment. No limit for date or publication language was imposed and this study was registered at the International Prospective Register of Systematic Reviews (PROSPERO), with nine articles included. Syrcle's protocol was used to evaluate bias in the selected studies. RESULTS Nine articles were included. Infection by P. gingivalis or the administration of Pg-LPS increased the production of the inflammatory mediators, TNF-α (tumor necrosis factor-alpha), IL-6 (interleukin-6), and IL-1β (interleukin-1beta), augmented Aβ (amyloid beta) production, and activated the complement system, causing inflammation, brain tissue degeneration, and cognitive impairment, consistent with the damage in AD. CONCLUSIONS Infection by P. gingivalis and Pg-LPS administration appears to be in relation with the pathogenesis of AD by activating the complement cascade, increasing Aβ production and augmenting pro-inflammatory cytokine expression, causing age-dependent brain inflammation, neuroinflammation, and neurodegeneration. CLINICAL RELEVANCE Taking into account the importance of holistic treatment in the dental office, this study focuses on identifying highly prevalent oral diseases, such as periodontal disease, as risk factors for the aggravation of degenerative diseases in the elderly population.
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Taudte N, Linnert M, Rahfeld JU, Piechotta A, Ramsbeck D, Buchholz M, Kolenko P, Parthier C, Houston JA, Veillard F, Eick S, Potempa J, Schilling S, Demuth HU, Stubbs MT. Mammalian-like type II glutaminyl cyclases in Porphyromonas gingivalis and other oral pathogenic bacteria as targets for treatment of periodontitis. J Biol Chem 2021; 296:100263. [PMID: 33837744 PMCID: PMC7948796 DOI: 10.1016/j.jbc.2021.100263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/29/2020] [Accepted: 01/05/2021] [Indexed: 12/25/2022] Open
Abstract
The development of a targeted therapy would significantly improve the treatment of periodontitis and its associated diseases including Alzheimer’s disease, rheumatoid arthritis, and cardiovascular diseases. Glutaminyl cyclases (QCs) from the oral pathogens Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia represent attractive target enzymes for small-molecule inhibitor development, as their action is likely to stabilize essential periplasmic and outer membrane proteins by N-terminal pyroglutamination. In contrast to other microbial QCs that utilize the so-called type I enzymes, these oral pathogens possess sequences corresponding to type II QCs, observed hitherto only in animals. However, whether differences between these bacteroidal QCs and animal QCs are sufficient to enable development of selective inhibitors is not clear. To learn more, we recombinantly expressed all three QCs. They exhibit comparable catalytic efficiencies and are inhibited by metal chelators. Crystal structures of the enzymes from P. gingivalis (PgQC) and T. forsythia (TfQC) reveal a tertiary structure composed of an eight-stranded β-sheet surrounded by seven α-helices, typical of animal type II QCs. In each case, an active site Zn ion is tetrahedrally coordinated by conserved residues. Nevertheless, significant differences to mammalian enzymes are found around the active site of the bacteroidal enzymes. Application of a PgQC-selective inhibitor described here for the first time results in growth inhibition of two P. gingivalis clinical isolates in a dose-dependent manner. The insights gained by these studies will assist in the development of highly specific small-molecule bacteroidal QC inhibitors, paving the way for alternative therapies against periodontitis and associated diseases.
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Affiliation(s)
- Nadine Taudte
- Periotrap Pharmaceuticals GmbH, Halle (Saale), Germany
| | - Miriam Linnert
- Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany
| | - Jens-Ulrich Rahfeld
- Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany.
| | - Anke Piechotta
- Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany
| | - Daniel Ramsbeck
- Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany
| | - Mirko Buchholz
- Periotrap Pharmaceuticals GmbH, Halle (Saale), Germany; Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany
| | - Petr Kolenko
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Christoph Parthier
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - John A Houston
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, Kentucky, USA
| | - Florian Veillard
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Sigrun Eick
- Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Jan Potempa
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, Kentucky, USA; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Stephan Schilling
- Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany; Angewandte Biowissenschaften und Prozesstechnik, Hochschule Anhalt, Köthen, Germany
| | - Hans-Ulrich Demuth
- Department of Molecular Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle (Saale), Germany
| | - Milton T Stubbs
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany; ZIK HALOmem, Charles-Tanford-Proteinzentrum, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
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Hashioka S, Wu Z, Klegeris A. Glia-Driven Neuroinflammation and Systemic Inflammation in Alzheimer's Disease. Curr Neuropharmacol 2021; 19:908-924. [PMID: 33176652 PMCID: PMC8686312 DOI: 10.2174/1570159x18666201111104509] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/28/2020] [Accepted: 11/06/2020] [Indexed: 11/29/2022] Open
Abstract
The neuroinflammatory hypothesis of Alzheimer's disease (AD) was proposed more than 30 years ago. The involvement of the two main types of glial cells microglia and astrocytes, in neuroinflammation, was suggested early on. In this review, we highlight that the exact contributions of reactive glia to AD pathogenesis remain difficult to define, likely due to the heterogeneity of glia populations and alterations in their activation states through the stages of AD progression. In the case of microglia, it is becoming apparent that both beneficially and adversely activated cell populations can be identified at various stages of AD, which could be selectively targeted to either limit their damaging actions or enhance beneficial functions. In the case of astrocytes, less information is available about potential subpopulations of reactive cells; it also remains elusive whether astrocytes contribute to the neuropathology of AD by mainly gaining neurotoxic functions or losing their ability to support neurons due to astrocyte damage. We identify L-type calcium channel blocker, nimodipine, as a candidate drug for AD, which potentially targets both astrocytes and microglia. It has already shown consistent beneficial effects in basic experimental and clinical studies. We also highlight the recent evidence linking peripheral inflammation and neuroinflammation. Several chronic systemic inflammatory diseases, such as obesity, type 2 diabetes mellitus, and periodontitis, can cause immune priming or adverse activation of glia, thus exacerbating neuroinflammation and increasing risk or facilitating the progression of AD. Therefore, reducing peripheral inflammation is a potentially effective strategy for lowering AD prevalence.
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Affiliation(s)
- Sadayuki Hashioka
- Address correspondence to these authors at the Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan;, E-mail: and Department of Biology, Faculty of Science, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada; E-mail:
| | | | - Andis Klegeris
- Address correspondence to these authors at the Department of Psychiatry, Shimane University, 89-1 Enya-cho, Izumo, Shimane 693-8501, Japan;, E-mail: and Department of Biology, Faculty of Science, University of British Columbia Okanagan Campus, Kelowna, BC, V1V 1V7, Canada; E-mail:
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Kanagasingam S, Chukkapalli SS, Welbury R, Singhrao SK. Porphyromonas gingivalis is a Strong Risk Factor for Alzheimer's Disease. J Alzheimers Dis Rep 2020; 4:501-511. [PMID: 33532698 PMCID: PMC7835991 DOI: 10.3233/adr-200250] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Porphyromonas gingivalis (P. gingivalis) is one of the several important bacterial pathogens associated with the sporadic Alzheimer’s disease (AD). Different serotypes are either capsulated or are non-capsulated. It has been demonstrated that P. gingivalis (non-capsulated) can reproduce the neurodegenerative AD-like changes in vitro, and a capsular P. gingivalis (strain W83) could reproduce the cardinal hallmark lesions of AD in a wild-type mouse model. All P. gingivalis forms express proteolytically active proteases that enable cleavage of the amyloid-β protin precursor (AβPP) and tau resulting in the formation of amyloid-β and neurofibrillary tangles. Tau is an established substrate for gingipains, which can cleave tau into various peptides. Some of the P. gingivalis fragmented tau protein peptides contain “VQIINK” and “VQIVYK” hexapeptide motifs which map to the flanking regions of the microtubule binding domains and are also found in paired helical filaments that form NFTs. P. gingivalis can induce peripheral inflammation in periodontitis and can also initiate signaling pathways that activate kinases, which in turn, phosphorylate neuronal tau. Periodontal disease related inflammation has metabolic implications for an individual’s peripheral and brain health as patients suffering from generalized periodontitis often have related co-morbidities and are “at risk” of developing AD. The aim here is to discuss the role of P. gingivalis behind such associations with the backdrop of huge efforts to test P. gingivalis virulence factors clinically (GAIN Trial: Phase 2/3 Study of COR388 in Subjects with AD) with inhibitors, which may lead to an intervention by reducing the pathogenic bacterial load.
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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
| | - Sasanka S Chukkapalli
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - 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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Bahar B, Singhrao SK. An evaluation of the molecular mode of action of trans-resveratrol in the Porphyromonas gingivalis lipopolysaccharide challenged neuronal cell model. Mol Biol Rep 2020; 48:147-156. [PMID: 33289908 PMCID: PMC7884301 DOI: 10.1007/s11033-020-06024-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/19/2020] [Indexed: 12/31/2022]
Abstract
Porphyromonas gingivalis triggers a range of innate immune responses in the host that may contribute to the development of periodontitis and dementing diseases including Alzheimer's disease (AD). This study aimed to assess the mode of action of trans-resveratrol in modulating the P. gingivalis lipopolysaccharide (PgLPS) induced metabolic inflammation in a neuronal cell model. Confluent IMR-32 neuroblastoma cells were treated with trans-resveratrol from Polygonum cuspidatum in the presence or absence of PgLPS. The abundance of messenger ribo-nucleic acid (mRNA) transcripts of a panel of 92 genes was quantitatively assessed through targeted transcriptome profiling technique and the biochemical pathways affected were identified through Ingenuity Pathway Analysis. Gene expression analysis revealed that trans-resveratrol down-regulated the mRNA of multiple gene markers including growth factors, transcription factors, kinases, trans-membrane receptors, cytokines and enzymes that were otherwise activated by PgLPS treatment of IMR-32 neuroblastoma cells. Pathway analysis demonstrated that the cellular oxidative stress caused by the activation of phosphoinositide-3-kinase/Akt1 (PI3K/Akt1) pathway that leads to the production of reactive oxygen species (ROS), chronic inflammatory response induced by the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) pathway and nutrient utilization pathways were favourably modulated by trans-resveratrol in the PgLPS challenged IMR-32 cells. This study demonstrates the potential of trans-resveratrol as a bioactive compound with multiple modes of intracellular action further supporting its therapeutic application in neuroinflammatory diseases.
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Affiliation(s)
- Bojlul Bahar
- International Institute of Nutritional Sciences and Food Safety Studies, School of Sport and Health Sciences, University of Central Lancashire, Preston, PR1 2HE, Lancashire, 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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Nakanishi H, Nonaka S, Wu Z. Microglial Cathepsin B and Porphyromonas gingivalis Gingipains as Potential Therapeutic Targets for Sporadic Alzheimer’s Disease. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:495-502. [DOI: 10.2174/1871527319666200708125130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/17/2020] [Accepted: 04/20/2020] [Indexed: 01/19/2023]
Abstract
Many efforts have been made to develop therapeutic agents for Alzheimer’s Disease (AD)
based on the amyloid cascade hypothesis, but there is no effective therapeutic agent at present. Now,
much attention has been paid to infiltrate pathogens in the brain as a trigger of AD. These pathogens,
or their virulence factors, may directly cross a weakened blood-brain barrier, reach the brain and cause
neurological damage by eliciting neuroinflammation. Moreover, there is growing clinical evidence of
a correlation between periodontitis and cognitive decline in AD patients. Recent studies have revealed
that microglial cathepsin B is increasingly induced by lipopolysaccharide of Porphylomonas gingivalis,
a major pathogen of periodontal disease. Moreover, gingipains produced by P. gingivalis play
critical roles in neuroinflammation mediated by microglia and cognitive decline in mice. Furthermore,
an orally bioavailable and brain-permeable inhibitor of gingipain is now being tested in AD patients. It
is largely expected that clinical studies countering bacterial virulence factors may pave the way to establish
the prevention and early treatment of AD.
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Affiliation(s)
- Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Zhou Wu
- OBT Research Center, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Mei F, Xie M, Huang X, Long Y, Lu X, Wang X, Chen L. Porphyromonas gingivalis and Its Systemic Impact: Current Status. Pathogens 2020; 9:pathogens9110944. [PMID: 33202751 PMCID: PMC7696708 DOI: 10.3390/pathogens9110944] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/24/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
The relationship between periodontitis and systemic diseases, notably including atherosclerosis and diabetes, has been studied for several years. Porphyromonas gingivalis, a prominent component of oral microorganism communities, is the main pathogen that causes periodontitis. As a result of the extensive analysis of this organism, the evidence of its connection to systemic diseases has become more apparent over the last decade. A significant amount of research has explored the role of Porphyromonas gingivalis in atherosclerosis, Alzheimer's disease, rheumatoid arthritis, diabetes, and adverse pregnancy outcomes, while relatively few studies have examined its contribution to respiratory diseases, nonalcoholic fatty liver disease, and depression. Here, we provide an overview of the current state of knowledge about Porphyromonas gingivalis and its systemic impact in an aim to inform readers of the existing epidemiological evidence and the most recent preclinical studies. Additionally, the possible mechanisms by which Porphyromonas gingivalis is involved in the onset or exacerbation of diseases, together with its effects on systemic health, are covered. Although a few results remain controversial, it is now evident that Porphyromonas gingivalis should be regarded as a modifiable factor for several diseases.
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Affiliation(s)
- Feng Mei
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (F.M.); (M.X.); (X.H.); (Y.L.); (X.L.)
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China
| | - Mengru Xie
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (F.M.); (M.X.); (X.H.); (Y.L.); (X.L.)
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China
| | - Xiaofei Huang
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (F.M.); (M.X.); (X.H.); (Y.L.); (X.L.)
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China
| | - Yanlin Long
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (F.M.); (M.X.); (X.H.); (Y.L.); (X.L.)
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China
| | - Xiaofeng Lu
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (F.M.); (M.X.); (X.H.); (Y.L.); (X.L.)
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China
| | - Xiaoli Wang
- Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
- Correspondence: (X.W.); (L.C.)
| | - Lili Chen
- Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; (F.M.); (M.X.); (X.H.); (Y.L.); (X.L.)
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan 430022, China
- Correspondence: (X.W.); (L.C.)
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Coniferyl Aldehyde Inhibits the Inflammatory Effects of Leptomeningeal Cells by Suppressing the JAK2 Signaling. BIOMED RESEARCH INTERNATIONAL 2020; 2020:4616308. [PMID: 33015166 PMCID: PMC7512043 DOI: 10.1155/2020/4616308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/29/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022]
Abstract
Background The brain is in many ways an immunologically and pharmacologically privileged site because of the blood-brain barrier (BBB). But for chronic peripheral inflammation, inflammatory signals can be transmitted from the peripheral system into the central nervous system (CNS) through multiple channels and result in neuroinflammation. Leptomeningeal cells that form the BBB can trigger one signaling pathway by releasing cytokines to transmit inflammatory signals. Besides, the Janus kinase (JAK) family may have a certain function in the activation of leptomeninges. In the present study, we try to use coniferyl aldehyde (CA), a natural anti-inflammatory phenolic compound, to inhibit this inflammatory process and elucidate the underlying molecular mechanisms. Results Secretion of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) significantly increased after incubation with P. gingivalis. Moreover, TNF-α, IL-1β, and IL-6 levels were upregulated, and the JAK2 signaling was enhanced in leptomeningeal cells in a conditioned medium from activated macrophages, which leads to the immune response in microglia. However, this inflammatory effect of leptomeningeal cells was reversed by CA administration, accompanied by the decreased immune response in microglia. The western blot assay revealed that JAK2 phosphorylation was suppressed in leptomeningeal cells treated with CA. Conclusions This study demonstrates that activated macrophages by P. gingivalis markedly induce the release of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) from leptomeningeal cells, thereby activating the JAK2 signaling pathway and subsequently enhancing immune responses in microglia in the CNS. CA effectively inhibits the inflammatory effect of leptomeningeal cells via suppressing the JAK2 signaling pathway.
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Abstract
Porphyromonas gingivalis is a gram-negative, rod-shaped, nonmotile bacterium belonging to the phylum Bacteroidetes. It produces abundant amounts of proteases in both cell-associated and secretory forms, including a group of cysteine proteases referred to as gingipains, which have attracted much attention due to their high proteolytic activity associated with pathogenicity. Gingipains are grouped into arginine (R)-specific (RgpA and RgpB) and lysine (K)-specific (Kgp) types. Both Rgp (collective term for RgpA and RgpB) and Kgp gingipains play crucial roles in the virulence of P. gingivalis, including the degradation of host periodontal tissues, disruption of host defense mechanisms, and loss of viability in host cells, such as fibroblasts and endothelial cells. In addition to their function in virulence, gingipains are also essential for the growth and survival of P. gingivalis in periodontal pockets through the acquisition of amino acids and heme groups. Furthermore, Rgp and Kgp gingipains are critical in processing fimbriae and several bacterial proteins that contribute to hemagglutination, coaggregation, and hemoglobin binding. This chapter describes the methods used to analyze gingipains.
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