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Association between periodontitis and Alzheimer's disease and its impact on the self-perceived oral health status: a case-control study. Clin Oral Investig 2020; 25:555-562. [PMID: 32772327 DOI: 10.1007/s00784-020-03489-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 07/30/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE To test the hypothesis that periodontitis is associated with AD and search whether periodontal and other variables would negatively impact the oral health-related quality of life (OHRQoL) perception. MATERIALS AND METHODS Oral examinations and interview on self-perceived oral health status (Geriatric Oral Health Assessment Index (GOHAI) questionnaire (higher score corresponds to better perceived oral status)) were carried out and socio-demographic data were collected from outpatients with mild to moderate AD (cases, n = 50) and from their age- and sex-matched family caregivers (controls, n = 52). Full-mouth periodontal examination was performed. Significance of differences between groups was sought by chi-square, Student's t, or the Mann-Whitney test. The association between the variables periodontitis, probing depth (PD) ≥ 5 mm, and clinical attachment loss (CAL) ≥ 5 mm with the variable group was tested in binary logistic regression models (LRMs). LRMs were used to test the association of oral findings, demographics, and group with GOHAI. RESULTS Cases had fewer teeth and greater CAL than controls. Cases had a superior percentage of sites with plaque, calculus, and bleeding on probing than controls. Cases had greater GOHAI scores than controls. Periodontitis was a variable most likely associated with AD (OR = 11.08, p < 0.001). None of the oral findings or demographics, but group, was associated with GOHAI (OR = 14.45, p < 0.001). CONCLUSION Periodontitis is associated with AD, but not with patients' OHRQoL. CLINICAL RELEVANCE Health care professionals must be aware that AD patients should have a periodic thorough oral examination and preventive intervention aiming at their welfare and maintenance of a pain-free functional dentition.
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Lu Q, Zhu H, Liu X, Tang C. Icariin sustains the proliferation and differentiation of Aβ 25-35-treated hippocampal neural stem cells via the BDNF-TrkB-ERK/Akt signaling pathway. Neurol Res 2020; 42:936-945. [PMID: 32727295 DOI: 10.1080/01616412.2020.1792701] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Icariin (ICA) can be potentially used to treat Alzheimer's disease (AD), but the mechanism was not clear. The current study explored the effects of ICA on hippocampal neural stem cells, aiming to provide a comprehensive basis for its clinical application. METHODS Hippocampal neural stem cells were isolated from newborn rats and their differentiation ability was evaluated by performing immunofluorescence staining. Next, Aβ cell model was constructed by treating the cells with Aβ25-35, and then the model was further treated by ICA or shBDNF or the two in combination. The viability and differentiation of the cells were, respectively, analyzed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide (MTT) and flow cytometry. The expression of BDNF-TrkB-ERK/Akt signaling pathway was assessed by quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot (WB). RESULTS The hippocampal neural stem cells can differentiate into neurons and astrocytes. ICA effectively promoted the viability and differentiation of Aβ cell models. The expression levels of BDNF and TrkB in Aβ cell models were obviously decreased, which were noticeably increased by ICA. Moreover, BDNF knockdown further inhibited the viability and differentiation of Aβ model cells, which could be reversed by ICA. BDNF knockdown not only suppressed the expressions of BDNF and TrkB in Aβ cell models but also effectively prevented the phosphorylation of ERK/Akt; however, these phenomena were significantly alleviated by ICA treatment. DISCUSSION ICA promoted the proliferation and differentiation of Aβ25-35-treated hippocampal neural stem cells through BDNF-TrkB-ERK/Akt signaling pathway. The current findings might contribute to the treatment of AD.
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Affiliation(s)
- Quan Lu
- Department of Neurology, Jingmen No.1 People's Hospital , Jingmen, Hubei, China
| | - Hailing Zhu
- Department of Emergency, Jingmen No.1 People's Hospital , Jingmen, Hubei, China
| | - Xuejiao Liu
- Department of Urology, Jingmen No.1 People's Hospital , Jingmen, Hubei, China
| | - Congfeng Tang
- Department of Neurology, Jingmen No.1 People's Hospital , Jingmen, Hubei, China
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Iqbal UH, Zeng E, Pasinetti GM. The Use of Antimicrobial and Antiviral Drugs in Alzheimer's Disease. Int J Mol Sci 2020; 21:E4920. [PMID: 32664669 PMCID: PMC7404195 DOI: 10.3390/ijms21144920] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/15/2022] Open
Abstract
The aggregation and accumulation of amyloid-β plaques and tau proteins in the brain have been central characteristics in the pathophysiology of Alzheimer's disease (AD), making them the focus of most of the research exploring potential therapeutics for this neurodegenerative disease. With success in interventions aimed at depleting amyloid-β peptides being limited at best, a greater understanding of the physiological role of amyloid-β peptides is needed. The development of amyloid-β plaques has been determined to occur 10-20 years prior to AD symptom manifestation, hence earlier interventions might be necessary to address presymptomatic AD. Furthermore, recent studies have suggested that amyloid-β peptides may play a role in innate immunity as an antimicrobial peptide. These findings, coupled with the evidence of pathogens such as viruses and bacteria in AD brains, suggests that the buildup of amyloid-β plaques could be a response to the presence of viruses and bacteria. This has led to the foundation of the antimicrobial hypothesis for AD. The present review will highlight the current understanding of amyloid-β, and the role of bacteria and viruses in AD, and will also explore the therapeutic potential of antimicrobial and antiviral drugs in Alzheimer's disease.
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Affiliation(s)
| | | | - Giulio M. Pasinetti
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (U.H.I.); (E.Z.)
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Stivala A, Genovese C, Bonaccorso C, Di Salvatore V, Petronio Petronio G, Garozzo A, Salmeri M. Comparison of Cell Culture with Three Conventional Polymerase Chain Reactions for Detecting Chlamydophila pneumoniae in Adult's Pharyngotonsillitis. Curr Microbiol 2020; 77:2841-2846. [PMID: 32607824 DOI: 10.1007/s00284-020-02106-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 06/23/2020] [Indexed: 10/24/2022]
Abstract
Chlamydophila pneumoniae is an intracellular pathogen responsible for respiratory tract infections. The isolation of the microorganism from clinical specimens is essential for a diagnosis. However, the identification of C. pneumoniae by cell cultures is very difficult besides strongly depending on the sample conditions. The study aimed to investigate, in adult patients with pharyngotonsillitis, the frequency of Chlamydophila pneumoniae detection by cell cultures and three conventional PCRs (a conventional PCR targeting the 16S rRNA gene and two nested PCRs, targeting the 16S rRNA gene and the ompA gene, respectively). The presence of chlamydial inclusion in cell cultures was observed in 11/94 samples (11.70%) by IFA. C. pneumoniae DNA was detected in 12/94 (12.76%) specimens by the 16S rRNA gene nested PCR, 4/94 (4.26%) by ompA gene nested PCR, and in 2/94 (2.13%) by 16S rRNA single-step PCR. Our data show poor agreement between the three applied DNA-amplification methods; in fact, only 16S rRNA gene nested PCR showed a statistically significant difference. Moreover, this result allowed us to achieve a definitive confirmation of the previous finding and to avoid the risk of an overestimation of the C. pneumoniae as a pathogen in pharyngotonsillitis.
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Affiliation(s)
- Aldo Stivala
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123, Catania, Italy
| | - Carlo Genovese
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123, Catania, Italy. .,Nacture S.R.L, Spin-Off University of Catania, Via Santa Sofia 97, 95123, Catania, Italy.
| | - Claudia Bonaccorso
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123, Catania, Italy
| | - Valentina Di Salvatore
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123, Catania, Italy
| | - Giulio Petronio Petronio
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, Via Francesco de Sanctis 1, 86100, Campobasso, Italy
| | - Adriana Garozzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123, Catania, Italy
| | - Mario Salmeri
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 97, 95123, Catania, Italy
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Fülöp T, Munawara U, Larbi A, Desroches M, Rodrigues S, Catanzaro M, Guidolin A, Khalil A, Bernier F, Barron AE, Hirokawa K, Beauregard PB, Dumoulin D, Bellenger JP, Witkowski JM, Frost E. Targeting Infectious Agents as a Therapeutic Strategy in Alzheimer's Disease. CNS Drugs 2020; 34:673-695. [PMID: 32458360 PMCID: PMC9020372 DOI: 10.1007/s40263-020-00737-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent dementia in the world. Its cause(s) are presently largely unknown. The most common explanation for AD, now, is the amyloid cascade hypothesis, which states that the cause of AD is senile plaque formation by the amyloid β peptide, and the formation of neurofibrillary tangles by hyperphosphorylated tau. A second, burgeoning theory by which to explain AD is based on the infection hypothesis. Much experimental and epidemiological data support the involvement of infections in the development of dementia. According to this mechanism, the infection either directly or via microbial virulence factors precedes the formation of amyloid β plaques. The amyloid β peptide, possessing antimicrobial properties, may be beneficial at an early stage of AD, but becomes detrimental with the progression of the disease, concomitantly with alterations to the innate immune system at both the peripheral and central levels. Infection results in neuroinflammation, leading to, and sustained by, systemic inflammation, causing eventual neurodegeneration, and the senescence of the immune cells. The sources of AD-involved microbes are various body microbiome communities from the gut, mouth, nose, and skin. The infection hypothesis of AD opens a vista to new therapeutic approaches, either by treating the infection itself or modulating the immune system, its senescence, or the body's metabolism, either separately, in parallel, or in a multi-step way.
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Affiliation(s)
- Tamàs Fülöp
- Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Research Center on Aging, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada.
| | - Usma Munawara
- Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Research Center on Aging, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Anis Larbi
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Immunos Building, Biopolis, Singapore, Singapore
- Department of Biology, Faculty of Science, University Tunis El Manar, Tunis, Tunisia
| | - Mathieu Desroches
- MathNeuro Team, Inria Sophia Antipolis Méditerranée, Valbonne, France
- Université Côte d'Azur, Nice, France
| | - Serafim Rodrigues
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
- BCAM, The Basque Center for Applied Mathematics, Bilbao, Spain
| | - Michele Catanzaro
- Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Research Center on Aging, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
- Department of Drug Sciences, University of Pavia, Pavia, Italy
| | - Andrea Guidolin
- BCAM, The Basque Center for Applied Mathematics, Bilbao, Spain
| | - Abdelouahed Khalil
- Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Research Center on Aging, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - François Bernier
- Next Generation Science Institute, Morinaga Milk Industry Co., Ltd., Zama, Japan
| | - Annelise E Barron
- Department of Bioengineering, Stanford School of Medicine, Stanford, CA, USA
| | - Katsuiku Hirokawa
- Department of Pathology, Institute of Health and Life Science, Tokyo and Nito-memory Nakanosogo Hospital, Tokyo Med. Dent. University, Tokyo, Japan
| | - Pascale B Beauregard
- Department of Biology, Faculty of Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - David Dumoulin
- Department of Biology, Faculty of Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Jean-Philippe Bellenger
- Department of Chemistry, Faculty of Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Jacek M Witkowski
- Department of Pathophysiology, Medical University of Gdansk, Gdansk, Poland
| | - Eric Frost
- Department of Microbiology and Infectious diseases, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
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González-Sánchez M, Bartolome F, Antequera D, Puertas-Martín V, González P, Gómez-Grande A, Llamas-Velasco S, Herrero-San Martín A, Pérez-Martínez D, Villarejo-Galende A, Atienza M, Palomar-Bonet M, Cantero JL, Perry G, Orive G, Ibañez B, Bueno H, Fuster V, Carro E. Decreased salivary lactoferrin levels are specific to Alzheimer's disease. EBioMedicine 2020; 57:102834. [PMID: 32586758 PMCID: PMC7378957 DOI: 10.1016/j.ebiom.2020.102834] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/15/2020] [Accepted: 05/29/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Evidences of infectious pathogens in Alzheimer's disease (AD) brains may suggest a deteriorated innate immune system in AD pathophysiology. We previously demonstrated reduced salivary lactoferrin (Lf) levels, one of the major antimicrobial proteins, in AD patients. METHODS To assess the clinical utility of salivary Lf for AD diagnosis, we examine the relationship between salivary Lf and cerebral amyloid-β (Aβ) load using amyloid-Positron-Emission Tomography (PET) neuroimaging, in two different cross-sectional cohorts including patients with different neurodegenerative disorders. FINDINGS The diagnostic performance of salivary Lf in the cohort 1 had an area under the curve [AUC] of 0•95 (0•911-0•992) for the differentiation of the prodromal AD/AD group positive for amyloid-PET (PET+) versus healthy group, and 0•97 (0•924-1) versus the frontotemporal dementia (FTD) group. In the cohort 2, salivary Lf had also an excellent diagnostic performance in the health control group versus prodromal AD comparison: AUC 0•93 (0•876-0•989). Salivary Lf detected prodromal AD and AD dementia distinguishing them from FTD with over 87% sensitivity and 91% specificity. INTERPRETATION Salivary Lf seems to have a very good diagnostic performance to detect AD. Our findings support the possible utility of salivary Lf as a new non-invasive and cost-effective AD biomarker. FUNDING Instituto de Salud Carlos III (FIS15/00780, FIS18/00118), FEDER, Comunidad de Madrid (S2017/BMD-3700; NEUROMETAB-CM), and CIBERNED (PI2016/01) to E.C.; Spanish Ministry of Economy and Competitiveness (SAF2017-85310-R) to J.L.C., and (PSI2017-85311-P) to M.A.; International Centre on ageing CENIE-POCTEP (0348_CIE_6_E) to M.A.; Instituto de Salud Carlos III (PIE16/00021, PI17/01799), to H.B.
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Affiliation(s)
- Marta González-Sánchez
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; Neurology Service Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Fernando Bartolome
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain.
| | - Desiree Antequera
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain
| | - Veronica Puertas-Martín
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares, Madrid, Spain; Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain
| | - Pilar González
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain; CIBER de Enfermedades Cardiovasculares, Madrid, Spain; Hospital Universitario 12 de Octubre Research Institute (imas12), Madrid, Spain
| | - Adolfo Gómez-Grande
- Nuclear Medicine Service, Hospital Universitario 12 de Octubre, Madrid, Spain; Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain
| | - Sara Llamas-Velasco
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; Neurology Service Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Alejandro Herrero-San Martín
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; Neurology Service Hospital Universitario 12 de Octubre, Madrid, Spain
| | - David Pérez-Martínez
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; Neurology Service Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Alberto Villarejo-Galende
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain; Neurology Service Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Mercedes Atienza
- Laboratory of Functional Neuroscience, Pablo de Olavide University, Seville, Spain, CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, Spain
| | - Miriam Palomar-Bonet
- Laboratory of Functional Neuroscience, Pablo de Olavide University, Seville, Spain, CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, Spain
| | - Jose Luis Cantero
- Laboratory of Functional Neuroscience, Pablo de Olavide University, Seville, Spain, CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, Spain
| | - George Perry
- Department of Biology and Neurosciences Institute, University of Texas at San Antonio, San Antonio, TX, USA
| | - Gorka Orive
- Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country, Vitoria, Spain; Networked Center for Biomedical Research in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Spain
| | - Borja Ibañez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain, CIBER de Enfermedades Cardiovasculares, Madrid, Spain; IIS-Fundacion Jiménez Díaz Hospital, Madrid, Spain
| | - Hector Bueno
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain, CIBER de Enfermedades Cardiovasculares, Madrid, Spain; Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain; Hospital Universitario 12 de Octubre Research Institute (imas12), Cardiology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Valentin Fuster
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain; Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Eva Carro
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Spain; Group of Neurodegenerative Diseases, Hospital Universitario 12 de Octubre Research Institute (imas12), 28041 Madrid, Spain.
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Matsushita K, Yamada-Furukawa M, Kurosawa M, Shikama Y. Periodontal Disease and Periodontal Disease-Related Bacteria Involved in the Pathogenesis of Alzheimer's Disease. J Inflamm Res 2020; 13:275-283. [PMID: 32636667 PMCID: PMC7335281 DOI: 10.2147/jir.s255309] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common cause of dementia, and it exhibits pathological properties such as deposition of extracellular amyloid β (Aβ) and abnormally phosphorylated Tau in nerve cells and a decrease of synapses. Conventionally, drugs targeting Aβ and its related molecules have been developed on the basis of the amyloid cascade hypothesis, but sufficient effects on the disease have not been obtained in past clinical trials. On the other hand, it has been pointed out that chronic inflammation and microbial infection in the brain may be involved in the pathogenesis of AD. Recently, attention has been focused on the relationship between the periodontopathic bacterium Porphylomonas gingivalis and AD. P. gingivalis and its toxins have been detected in autopsy brain tissues from patients with AD. In addition, pathological conditions of AD are formed or exacerbated in mice infected with P. gingivalis. Compounds that target the toxins of P. gingivalis ameliorate the pathogenesis of AD triggered by P. gingivalis infection. These findings indicate that the pathological condition of AD may be regulated by controlling the bacteria in the oral cavity and the body. In the current aging society, the importance of oral and periodontal care for preventing the onset of AD will increase.
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Affiliation(s)
- Kenji Matsushita
- Department of Oral Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Masae Yamada-Furukawa
- Department of Oral Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Mie Kurosawa
- Department of Oral Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
| | - Yosuke Shikama
- Department of Oral Disease Research, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511, Japan
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Sanders O, Rajagopal L. Phosphodiesterase Inhibitors for Alzheimer's Disease: A Systematic Review of Clinical Trials and Epidemiology with a Mechanistic Rationale. J Alzheimers Dis Rep 2020; 4:185-215. [PMID: 32715279 PMCID: PMC7369141 DOI: 10.3233/adr-200191] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Preclinical studies, clinical trials, and reviews suggest increasing 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) with phosphodiesterase inhibitors is disease-modifying in Alzheimer's disease (AD). cAMP/protein kinase A (PKA) and cGMP/protein kinase G (PKG) signaling are disrupted in AD. cAMP/PKA and cGMP/PKG activate cAMP response element binding protein (CREB). CREB binds mitochondrial and nuclear DNA, inducing synaptogenesis, memory, and neuronal survival gene (e.g., brain-derived neurotrophic factor) and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α). cAMP/PKA and cGMP/PKG activate Sirtuin-1, which activates PGC1α. PGC1α induces mitochondrial biogenesis and antioxidant genes (e.g.,Nrf2) and represses BACE1. cAMP and cGMP inhibit BACE1-inducing NFκB and tau-phosphorylating GSK3β. OBJECTIVE AND METHODS We review efficacy-testing clinical trials, epidemiology, and meta-analyses to critically investigate whether phosphodiesteraseinhibitors prevent or treat AD. RESULTS Caffeine and cilostazol may lower AD risk. Denbufylline and sildenafil clinical trials are promising but preliminary and inconclusive. PF-04447943 and BI 409,306 are ineffective. Vinpocetine, cilostazol, and nicergoline trials are mixed. Deprenyl/selegiline trials show only short-term benefits. Broad-spectrum phosphodiesterase inhibitor propentofylline has been shown in five phase III trials to improve cognition, dementia severity, activities of daily living, and global assessment in mild-to-moderate AD patients on multiple scales, including the ADAS-Cogand the CIBIC-Plus in an 18-month phase III clinical trial. However, two books claimed based on a MedScape article an 18-month phase III trial failed, so propentofylline was discontinued. Now, propentofylline is used to treat canine cognitive dysfunction, which, like AD, involves age-associated wild-type Aβ deposition. CONCLUSION Phosphodiesterase inhibitors may prevent and treat AD.
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Panza F, Lozupone M, Solfrizzi V, Watling M, Imbimbo BP. Time to test antibacterial therapy in Alzheimer's disease. Brain 2020; 142:2905-2929. [PMID: 31532495 DOI: 10.1093/brain/awz244] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/24/2019] [Accepted: 06/14/2019] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease is associated with cerebral accumulation of amyloid-β peptide and hyperphosphorylated tau. In the past 28 years, huge efforts have been made in attempting to treat the disease by reducing brain accumulation of amyloid-β in patients with Alzheimer's disease, with no success. While anti-amyloid-β therapies continue to be tested in prodromal patients with Alzheimer's disease and in subjects at risk of developing Alzheimer's disease, there is an urgent need to provide therapeutic support to patients with established Alzheimer's disease for whom current symptomatic treatment (acetylcholinesterase inhibitors and N-methyl d-aspartate antagonist) provide limited help. The possibility of an infectious aetiology for Alzheimer's disease has been repeatedly postulated over the past three decades. Infiltration of the brain by pathogens may act as a trigger or co-factor for Alzheimer's disease, with Herpes simplex virus type 1, Chlamydia pneumoniae, and Porphyromonas gingivalis being most frequently implicated. These pathogens may directly cross a weakened blood-brain barrier, reach the CNS and cause neurological damage by eliciting neuroinflammation. Alternatively, pathogens may cross a weakened intestinal barrier, reach vascular circulation and then cross blood-brain barrier or cause low grade chronic inflammation and subsequent neuroinflammation from the periphery. The gut microbiota comprises a complex community of microorganisms. Increased permeability of the gut and blood-brain barrier induced by microbiota dysbiosis may impact Alzheimer's disease pathogenesis. Inflammatory microorganisms in gut microbiota are associated with peripheral inflammation and brain amyloid-β deposition in subjects with cognitive impairment. Oral microbiota may also influence Alzheimer's disease risk through circulatory or neural access to the brain. At least two possibilities can be envisaged to explain the association of suspected pathogens and Alzheimer's disease. One is that patients with Alzheimer's disease are particularly prone to microbial infections. The other is that microbial infection is a contributing cause of Alzheimer's disease. Therapeutic trials with antivirals and/or antibacterials could resolve this dilemma. Indeed, antiviral agents are being tested in patients with Alzheimer's disease in double-blind placebo-controlled studies. Although combined antibiotic therapy was found to be effective in animal models of Alzheimer's disease, antibacterial drugs are not being widely investigated in patients with Alzheimer's disease. This is because it is not clear which bacterial populations in the gut of patients with Alzheimer's disease are overexpressed and if safe, selective antibacterials are available for them. On the other hand, a bacterial protease inhibitor targeting P. gingivalis toxins is now being tested in patients with Alzheimer's disease. Clinical studies are needed to test if countering bacterial infection may be beneficial in patients with established Alzheimer's disease.
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Affiliation(s)
- Francesco Panza
- Unit of Epidemiological Research on Aging, National Institute of Gastroenterology 'Saverio de Bellis', Research Hospital, Castellana Grotte, Bari, Italy
| | - Madia Lozupone
- Unit of Epidemiological Research on Aging, National Institute of Gastroenterology 'Saverio de Bellis', Research Hospital, Castellana Grotte, Bari, Italy
- Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs, University of Bari Aldo Moro, Bari, Italy
| | - Vincenzo Solfrizzi
- 'C. Frugoni' Internal and Geriatric Medicine and Memory Unit, University of Bari Aldo Moro, Bari, Italy
| | - Mark Watling
- Department of Research and Development, Chiesi Farmaceutici, Parma, Italy
| | - Bruno P Imbimbo
- Department of Research and Development, Chiesi Farmaceutici, Parma, Italy
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Yang J, Wise L, Fukuchi KI. TLR4 Cross-Talk With NLRP3 Inflammasome and Complement Signaling Pathways in Alzheimer's Disease. Front Immunol 2020; 11:724. [PMID: 32391019 PMCID: PMC7190872 DOI: 10.3389/fimmu.2020.00724] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/30/2020] [Indexed: 01/02/2023] Open
Abstract
Amyloid plaques, mainly composed of abnormally aggregated amyloid β-protein (Aβ) in the brain parenchyma, and neurofibrillary tangles (NFTs), consisting of hyperphosphorylated tau protein aggregates in neurons, are two pathological hallmarks of Alzheimer's disease (AD). Aβ fibrils and tau aggregates in the brain are closely associated with neuroinflammation and synapse loss, characterized by activated microglia and dystrophic neurites. Genome-wide genetic association studies revealed important roles of innate immune cells in the pathogenesis of late-onset AD by recognizing a dozen genetic risk loci that modulate innate immune activities. Furthermore, microglia, brain resident innate immune cells, have been increasingly recognized to play key, opposing roles in AD pathogenesis by either eliminating toxic Aβ aggregates and enhancing neuronal plasticity or producing proinflammatory cytokines, reactive oxygen species, and synaptotoxicity. Aggregated Aβ binds to toll-like receptor 4 (TLR4) and activates microglia, resulting in increased phagocytosis and cytokine production. Complement components are associated with amyloid plaques and NFTs. Aggregated Aβ can activate complement, leading to synapse pruning and loss by microglial phagocytosis. Systemic inflammation can activate microglial TLR4, NLRP3 inflammasome, and complement in the brain, leading to neuroinflammation, Aβ accumulation, synapse loss and neurodegeneration. The host immune response has been shown to function through complex crosstalk between the TLR, complement and inflammasome signaling pathways. Accordingly, targeting the molecular mechanisms underlying the TLR-complement-NLRP3 inflammasome signaling pathways can be a preventive and therapeutic approach for AD.
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Affiliation(s)
- Junling Yang
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| | - Leslie Wise
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| | - Ken-Ichiro Fukuchi
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
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Abstract
Nitric oxide/cyclic guanosine monophosphate (cGMP) signaling is compromised in Alzheimer’s disease (AD), and phosphodiesterase 5 (PDE5), which degrades cGMP, is upregulated. Sildenafil inhibits PDE5 and increases cGMP levels. Integrating previous findings, we determine that most doses of sildenafil (especially low doses) likely activate peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α) via protein kinase G-mediated cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) phosphorylation and/or Sirtuin-1 activation and PGC1α deacetylation. Via PGC1α signaling, low-dose sildenafil likely suppresses β-secretase 1 expression and amyloid-β (Aβ) generation, upregulates antioxidant enzymes, and induces mitochondrial biogenesis. Plus, sildenafil should increase brain perfusion, insulin sensitivity, long-term potentiation, and neurogenesis while suppressing neural apoptosis and inflammation. A systematic review of sildenafil in AD was undertaken. In vitro, sildenafil protected neural mitochondria from Aβ and advanced glycation end products. In transgenic AD mice, sildenafil was found to rescue deficits in CREB phosphorylation and memory, upregulate brain-derived neurotrophic factor, reduce reactive astrocytes and microglia, decrease interleukin-1β, interleukin-6, and tumor necrosis factor-α, decrease neural apoptosis, increase neurogenesis, and reduce tau hyperphosphorylation. All studies that tested Aβ levels reported significant improvements except the two that used the highest dosage, consistent with the dose-limiting effect of cGMP-induced phosphodiesterase 2 (PDE2) activation and cAMP depletion on PGC1α signaling. In AD patients, a single dose of sildenafil decreased spontaneous neural activity, increased cerebral blood flow, and increased the cerebral metabolic rate of oxygen. A randomized control trial of sildenafil (ideally with a PDE2 inhibitor) in AD patients is warranted.
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Ooi L, Dottori M, Cook AL, Engel M, Gautam V, Grubman A, Hernández D, King AE, Maksour S, Targa Dias Anastacio H, Balez R, Pébay A, Pouton C, Valenzuela M, White A, Williamson R. If Human Brain Organoids Are the Answer to Understanding Dementia, What Are the Questions? Neuroscientist 2020; 26:438-454. [PMID: 32281909 PMCID: PMC7539594 DOI: 10.1177/1073858420912404] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Because our beliefs regarding our individuality, autonomy, and personhood are intimately bound up with our brains, there is a public fascination with cerebral organoids, the "mini-brain," the "brain in a dish". At the same time, the ethical issues around organoids are only now being explored. What are the prospects of using human cerebral organoids to better understand, treat, or prevent dementia? Will human organoids represent an improvement on the current, less-than-satisfactory, animal models? When considering these questions, two major issues arise. One is the general challenge associated with using any stem cell-generated preparation for in vitro modelling (challenges amplified when using organoids compared with simpler cell culture systems). The other relates to complexities associated with defining and understanding what we mean by the term "dementia." We discuss 10 puzzles, issues, and stumbling blocks to watch for in the quest to model "dementia in a dish."
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Affiliation(s)
- Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia.,School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Mirella Dottori
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia.,School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia.,Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia.,Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony L Cook
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Martin Engel
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia.,School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Vini Gautam
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Alexandra Grubman
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.,Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, Victoria, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia
| | - Damián Hernández
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia.,Department of Surgery, University of Melbourne, Parkville, Victoria, Australia
| | - Anna E King
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Simon Maksour
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia.,School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia
| | - Helena Targa Dias Anastacio
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia.,School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Rachelle Balez
- Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia.,School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia
| | - Alice Pébay
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia.,Department of Surgery, University of Melbourne, Parkville, Victoria, Australia
| | - Colin Pouton
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Michael Valenzuela
- Regenerative Neuroscience Group, Brain and Mind Centre and Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Anthony White
- Queensland Institute of Medical Research Berghofer, Brisbane, Queensland, Australia
| | - Robert Williamson
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
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63
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Vorobyev SV, Shalepo KV, Spasibova EV, Savicheva AM, Grigor’ev AN. Infectious agents as a risk factor for Alzheimer’s disease. JOURNAL INFECTOLOGY 2020. [DOI: 10.22625/2072-6732-2020-12-1-5-13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cognitive disorders are one of the relevant problems of modern clinical medicine. This is due to both their high frequency of occurrence and significant negative impact, which has a violation of higher cortical functions on the quality of life of patients due to the deterioration of their social communication, as well as reducing the effectiveness of professional and household functions. The main cause of cognitive disorders is Alzheimer’s disease. At the same time, according to statistical studies, a significant increase in the incidence of the number of persons in the human population as a whole suffering from this pathology is predicted. At the heart of Alzheimer’s disease is a complex of pathobiochemical changes leading to synaptic dysfunction, accompanied by the development of atrophic changes in certain areas of the brain, against which a specific clinical picture is formed. The earliest and most important manifestation of Alzheimer’s disease is memory impairment for current events, which are subsequently joined by a number of other symptoms. The literature describes certain risk factors that contribute to the development of the disease, among which a certain place is occupied by infectious pathology. However, this aspect remains largely outside the traditional study of the pathogenesis of Alzheimer’s disease. In the review the analysis of the results of modern studies confirm the possible involvement of infections in the development of dementia of Alzheimer’s type.
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Affiliation(s)
| | | | - E. V. Spasibova
- Saint-Petersburg State Pediatric Medical University; The Research Institute of Obstetrics, Gynecology and Reproductology named after D.O. Ott
| | - A. M. Savicheva
- Saint-Petersburg State Pediatric Medical University; The Research Institute of Obstetrics, Gynecology and Reproductology named after D.O. Ott
| | - A. N. Grigor’ev
- The Research Institute of Obstetrics, Gynecology and Reproductology named after D.O. Ott
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64
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Kwan P, Konno H, Chan KY, Baum L. Rationale for the development of an Alzheimer's disease vaccine. Hum Vaccin Immunother 2020; 16:645-653. [PMID: 31526227 PMCID: PMC7227628 DOI: 10.1080/21645515.2019.1665453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 08/13/2019] [Accepted: 09/02/2019] [Indexed: 02/07/2023] Open
Abstract
Vaccination traditionally has targeted infectious agents and thus has not heretofore been used to prevent neurodegenerative illness. However, amyloid β (Aβ) or tau, which can act like infectious proteins, or prions, might induce Alzheimer's disease (AD). Furthermore, evidence suggests that traditional infectious agents, including certain viruses and bacteria, may trigger AD. It is therefore worth exploring whether removing such targets could prevent AD. Although failing to treat AD patients who already display cognitive impairment, Aβ monoclonal antibodies are being tested in pre-symptomatic, at-risk individuals to prevent dementia. These antibodies might become the first AD therapeutics. However, their high cost will keep them out of the arms of the vast majority of patients, who increasingly live in developing countries. Because vaccines produce antibodies internally at much lower cost, vaccination might be the most promising approach to reducing the global burden of dementia.
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Affiliation(s)
- Ping Kwan
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, P.R. China
- Sydney School of Veterinary Science, The University of Sydney, Sydney, Australia
| | - Haruki Konno
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, P.R. China
| | - Ka Yan Chan
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, P.R. China
| | - Larry Baum
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, P.R. China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, P.R. China
- Center for Genomic Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, P.R. China
- Department of Psychiatry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, P.R. China
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65
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Lax N, Fainstein N, Nishri Y, Ben-Zvi A, Ben-Hur T. Systemic microbial TLR2 agonists induce neurodegeneration in Alzheimer's disease mice. J Neuroinflammation 2020; 17:55. [PMID: 32059733 PMCID: PMC7023749 DOI: 10.1186/s12974-020-01738-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 02/05/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Accumulating data suggest a central role for brain microglia in mediating cortical neuronal death in Alzheimer's disease (AD), and for Toll-like receptor 2 (TLR2) in their toxic activation. Amyloid deposition in preclinical AD is associated with microglial activation but not directly with neurodegeneration. We examined in transgenic 5xFAD mice the hypothesis that systemic TLR2 agonists, derived from common infectious agents, may accelerate neurodegeneration in AD. METHODS Microbial wall-derived TLR2 agonists zymosan and lipoteichoic acid were administered intraperitoneally or intracerebroventricularly to 7-month-old wild-type or 5xFAD mice. Immunofluorescent stainings were used to quantify cortical neurons and evaluate tissue reaction. Microglial activation was assessed using functional assays, RNA expression, and FACS analysis. RESULTS Repeated low-dose systemic administration of zymosan or lipoteichoic acid killed cortical neurons in 5xFAD mice but not in wild-type mice. Direct CNS delivery of a selective TLR2 antagonist blocked the neurotoxicity of systemically administered zymosan, indicating that CNS TLR2 mediates this effect. Systemically administered zymosan crossed the disrupted blood-brain barrier in 5xFAD mice and entered brain parenchyma. By intracerebroventricular delivery, we found a dose- and exposure time-dependent acute neurotoxic effect of the microbial TLR2 agonist, killing cortical neurons. 5xFAD mice exhibited significantly increased vulnerability to TLR2 agonist-induced neuronal loss as compared to wild-type mice. Microbial TLR2-induced neurodegeneration was abolished by inhibiting microglia. The vulnerability of 5xFAD mice brains was mediated by an increase in number and neurotoxic phenotype of TLR2-expressing microglia. CONCLUSIONS We suggest that repeated exposure to microbial TLR2 agonists may facilitate neurodegeneration in AD by their microglial-mediated toxicity to the hyper-vulnerable environment of the AD brain.
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Affiliation(s)
- Neta Lax
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Nina Fainstein
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Yossi Nishri
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Ayal Ben-Zvi
- Department of Developmental Biology and Cancer Research, Institute of Medical Research Israel-Canada, Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Tamir Ben-Hur
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel.
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66
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Pape K, Tamouza R, Leboyer M, Zipp F. Immunoneuropsychiatry - novel perspectives on brain disorders. Nat Rev Neurol 2020; 15:317-328. [PMID: 30988501 DOI: 10.1038/s41582-019-0174-4] [Citation(s) in RCA: 267] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Immune processes have a vital role in CNS homeostasis, resilience and brain reserve. Our cognitive and social abilities rely on a highly sensitive and fine-tuned equilibrium of immune responses that involve both innate and adaptive immunity. Autoimmunity, chronic inflammation, infection and psychosocial stress can tip the scales towards disruption of higher-order networks. However, not only classical neuroinflammatory diseases, such as multiple sclerosis and autoimmune encephalitis, are caused by immune dysregulation that affects CNS function. Recent insight indicates that similar processes are involved in psychiatric diseases such as schizophrenia, autism spectrum disorder, bipolar disorder and depression. Pathways that are common to these disorders include microglial activation, pro-inflammatory cytokines, molecular mimicry, anti-neuronal autoantibodies, self-reactive T cells and disturbance of the blood-brain barrier. These discoveries challenge our traditional classification of neurological and psychiatric diseases. New clinical paths are required to identify subgroups of neuropsychiatric disorders that are phenotypically distinct but pathogenically related and to pave the way for mechanism-based immune treatments. Combined expertise from neurologists and psychiatrists will foster translation of these paths into clinical practice. The aim of this Review is to highlight outstanding findings that have transformed our understanding of neuropsychiatric diseases and to suggest new diagnostic and therapeutic criteria for the emerging field of immunoneuropsychiatry.
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Affiliation(s)
- Katrin Pape
- Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Ryad Tamouza
- Inserm, U955, Institut Mondor de la Recherche Biomédicale, Créteil, France.,Fondation FondaMental, Créteil, France.,AP-HP, Department of Psychiatry of Mondor University Hospital, DHU PePsy, University of Paris-Est-Créteil, Créteil, France
| | - Marion Leboyer
- Inserm, U955, Institut Mondor de la Recherche Biomédicale, Créteil, France.,Fondation FondaMental, Créteil, France.,AP-HP, Department of Psychiatry of Mondor University Hospital, DHU PePsy, University of Paris-Est-Créteil, Créteil, France
| | - Frauke Zipp
- Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
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67
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Xiao J, Katsumata N, Bernier F, Ohno K, Yamauchi Y, Odamaki T, Yoshikawa K, Ito K, Kaneko T. Probiotic Bifidobacterium breve in Improving Cognitive Functions of Older Adults with Suspected Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Trial. J Alzheimers Dis 2020; 77:139-147. [PMID: 32623402 PMCID: PMC7592675 DOI: 10.3233/jad-200488] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2020] [Indexed: 01/28/2023]
Abstract
BACKGROUND Probiotics use has been associated with modulation of inflammation and considered as a possible intervention for CNS diseases such as mild cognitive impairment (MCI) and dementia. OBJECTIVE We aimed to test the effect of the probiotic strain, Bifidobacterium breve A1 (MCC1274), to restore cognition in a physically healthy, suspected MCI population. METHODS In this randomized, double-blind, placebo-controlled trial, 80 healthy older adults suffering from MCI were divided into two even groups to receive once daily either probiotic (B. breve A1, 2×1010 CFU) or placebo for 16 weeks using a computer-generated algorithm. Cognitive functions were assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Japanese version of the MCI Screen (JMCIS) tests before and after the study as primary and secondary endpoints, respectively. RESULTS 79 participants completed the study, and no adverse events were observed. RBANS total score was significantly improved in probiotic group compared with placebo (mean between-group difference 11.3 [95% CI 6.7 to 15.8]; p < 0.0001) after 16 weeks of consumption, in particular with significant improvement in domain scores of immediate memory, visuospatial/constructional, and delayed memory (p < 0.0001), in both intention-to-treat (ITT) analysis and per-protocol (PP) analysis. JMCIS score was also improved versus placebo in ITT analysis (p = 0.052) and PP analysis (p = 0.036). CONCLUSION Study results indicate B. breve A1 is a safe and effective approach for improving memory functions of suspected MCI subjects.
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Affiliation(s)
- Jinzhong Xiao
- Morinaga Milk Industry Co., Ltd., Next Generation Science Institute, Kanagawa, Japan
| | - Noriko Katsumata
- Morinaga Milk Industry Co., Ltd., Next Generation Science Institute, Kanagawa, Japan
| | - Francois Bernier
- Morinaga Milk Industry Co., Ltd., Next Generation Science Institute, Kanagawa, Japan
| | - Kazuya Ohno
- Morinaga Milk Industry Co., Ltd., Next Generation Science Institute, Kanagawa, Japan
| | - Yuki Yamauchi
- Morinaga Milk Industry Co., Ltd., Next Generation Science Institute, Kanagawa, Japan
| | - Toshitaka Odamaki
- Morinaga Milk Industry Co., Ltd., Next Generation Science Institute, Kanagawa, Japan
| | | | - Kumie Ito
- Nihonbashi Sakura Clinic, Tokyo, Japan
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68
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Norins LC. Predicted economic damage from a quick, simple Alzheimer's disease cure. Med Hypotheses 2019; 133:109398. [DOI: 10.1016/j.mehy.2019.109398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/10/2019] [Accepted: 09/13/2019] [Indexed: 11/28/2022]
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69
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Bathini P, Brai E, Auber LA. Olfactory dysfunction in the pathophysiological continuum of dementia. Ageing Res Rev 2019; 55:100956. [PMID: 31479764 DOI: 10.1016/j.arr.2019.100956] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/29/2019] [Accepted: 08/26/2019] [Indexed: 12/21/2022]
Abstract
Sensory capacities like smell, taste, hearing, vision decline with aging, but increasing evidence show that sensory dysfunctions are one of the early signs diagnosing the conversion from physiological to pathological brain state. Smell loss represents the best characterized sense in clinical practice and is considered as one of the first preclinical signs of Alzheimer's and Parkinson's disease, occurring a decade or more before the onset of cognitive and motor symptoms. Despite the numerous scientific reports and the adoption in clinical practice, the etiology of sensory damage as prodromal of dementia remains largely unexplored and more studies are needed to resolve the mechanisms underlying sensory network dysfunction. Although both cognitive and sensory domains are progressively affected, loss of sensory experience in early stages plays a major role in reducing the autonomy of demented people in their daily tasks or even possibly contributing to their cognitive decline. Interestingly, the chemosensory circuitry is devoid of a blood brain barrier, representing a vulnerable port of entry for neurotoxic species that can spread to the brain. Furthermore, the exposure of the olfactory system to the external environment make it more susceptible to mechanical injury and trauma, which can cause degenerative neuroinflammation. In this review, we will summarize several findings about chemosensory impairment signing the conversion from healthy to pathological brain aging and we will try to connect those observations to the promising research linking environmental influences to sporadic dementia. The scientific body of knowledge will support the use of chemosensory diagnostics in the presymptomatic stages of AD and other biomarkers with the scope of finding treatment strategies before the onset of the disease.
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Affiliation(s)
- Praveen Bathini
- Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Emanuele Brai
- VIB-KU Leuven Center for Brain & Disease Research, Laboratory for the Research of Neurodegenerative Diseases, Leuven, Belgium
| | - Lavinia Alberi Auber
- Department of Medicine, University of Fribourg, Fribourg, Switzerland; Swiss Integrative Center of Human Health, Fribourg, Switzerland.
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70
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Abstract
Next to cancer, Alzheimer's disease (AD) and dementia is probably the most worrying health problem facing the Western world today. A large number of clinical trials have failed to show any benefit of the tested drugs in stabilizing or reversing the steady decline in cognitive function that is suffered by dementia patients. Although the pathological features of AD consisting of beta-amyloid plaques and tau tangles are well established, considerable debate exists concerning the genetic or lifestyle factors that predispose individuals to developing dementia. Photobiomodulation (PBM) describes the therapeutic use of red or near-infrared light to stimulate healing, relieve pain and inflammation, and prevent tissue from dying. In recent years PBM has been applied for a diverse range of brain disorders, frequently applied in a non-invasive manner by shining light on the head (transcranial PBM). The present review discusses the mechanisms of action of tPBM in the brain, and summarizes studies that have used tPBM to treat animal models of AD. The results of a limited number of clinical trials that have used tPBM to treat patients with AD and dementia are discussed.
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Affiliation(s)
- Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Dermatology, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
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71
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Qin Q, Li Y. Herpesviral infections and antimicrobial protection for Alzheimer's disease: Implications for prevention and treatment. J Med Virol 2019; 91:1368-1377. [PMID: 30997676 DOI: 10.1002/jmv.25481] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/04/2019] [Indexed: 02/05/2023]
Abstract
Accumulating evidence suggests that infections by herpesviruses might be closely linked to Alzheimer's disease (AD). Pathological hallmarks of AD brains include senile plaques induced by amyloid β peptide (Aβ) in the extracellular space and intracellular neurofibrillary tangles (NFTs) consisting of phosphorylated tau protein. The prevailing hypothesis for the mechanism of AD is amyloid cascade reaction. Recent studies revealed that infections by herpesviruses induce the similar pathological hallmarks of AD, including Aβ production, phosphorylation of tau (P-tau), oxidative stress, neuroinflammation, etc. Aβ peptide is regarded as one of the antimicrobial peptides, which inhibits HSV-1 replication. In the elderly, reactivation of herpesviruses might act as an initiator for amyloid cascade reaction in vulnerable individuals, triggering the neurofibrillary formation of phosphorylated tau and inducing oxidative stress and neuroinflammation, which can further contribute to the accumulation of Aβ and P-tau by impairing mitochondria and autophagosome. Epidemiological studies have shown AD susceptibility genes, such as APOE-ε4 allele, are highly linked to infections by herpesviruses. Interestingly, anti-herpesviral therapy significantly reduced the risk of AD in a large population study. Given that herpesviruses are arguably the most prevalent opportunistic pathogens and often reactivate in the elderly, it is reasonable to argue reactivation of herpesviruses might be major culprits for initiating AD in individuals carrying AD susceptibility genes. In this review, we summarize epidemiological and molecular evidence that support for a hypothesis of herpesviral infections and antimicrobial protection in the development of AD, and discuss the implications for future prevention and treatment of the disease.
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Affiliation(s)
- Qingsong Qin
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, Guangdong, China
| | - Yun Li
- Sleep Medicine Center, Shantou University Medical College, Shantou, Guangdong, China
- Mental Health Center, Shantou University Medical College, Shantou, Guangdong, China
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72
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Osorio C, Kanukuntla T, Diaz E, Jafri N, Cummings M, Sfera A. The Post-amyloid Era in Alzheimer's Disease: Trust Your Gut Feeling. Front Aging Neurosci 2019; 11:143. [PMID: 31297054 PMCID: PMC6608545 DOI: 10.3389/fnagi.2019.00143] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/29/2019] [Indexed: 12/14/2022] Open
Abstract
The amyloid hypothesis, the assumption that beta-amyloid toxicity is the primary cause of neuronal and synaptic loss, has been the mainstream research concept in Alzheimer's disease for the past two decades. Currently, this model is quietly being replaced by a more holistic, “systemic disease” paradigm which, like the aging process, affects multiple body tissues and organs, including the gut microbiota. It is well-established that inflammation is a hallmark of cellular senescence; however, the infection-senescence link has been less explored. Microbiota-induced senescence is a gradually emerging concept promoted by the discovery of pathogens and their products in Alzheimer's disease brains associated with senescent neurons, glia, and endothelial cells. Infectious agents have previously been associated with Alzheimer's disease, but the cause vs. effect issue could not be resolved. A recent study may have settled this debate as it shows that gingipain, a Porphyromonas gingivalis toxin, can be detected not only in Alzheimer's disease but also in the brains of older individuals deceased prior to developing the illness. In this review, we take the position that gut and other microbes from the body periphery reach the brain by triggering intestinal and blood-brain barrier senescence and disruption. We also surmise that novel Alzheimer's disease findings, including neuronal somatic mosaicism, iron dyshomeostasis, aggressive glial phenotypes, and loss of aerobic glycolysis, can be explained by the infection-senescence model. In addition, we discuss potential cellular senescence targets and therapeutic strategies, including iron chelators, inflammasome inhibitors, senolytic antibiotics, mitophagy inducers, and epigenetic metabolic reprograming.
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Affiliation(s)
- Carolina Osorio
- Psychiatry, Loma Linda University, Loma Linda, CA, United States
| | - Tulasi Kanukuntla
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Eddie Diaz
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Nyla Jafri
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Michael Cummings
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
| | - Adonis Sfera
- Department of Psychiatry, Patton State Hospital, San Bernardino, CA, United States
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Fulop T, Witkowski JM, Larbi A, Khalil A, Herbein G, Frost EH. Does HIV infection contribute to increased beta-amyloid synthesis and plaque formation leading to neurodegeneration and Alzheimer's disease? J Neurovirol 2019; 25:634-647. [PMID: 30868421 DOI: 10.1007/s13365-019-00732-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/24/2019] [Accepted: 02/01/2019] [Indexed: 10/27/2022]
Abstract
HIV infection in the combination antiretroviral therapy (cART) era has become a chronic disease with a life expectancy almost identical to those free from this infection. Concomitantly, chronic diseases such as neurodegenerative diseases have emerged as serious clinical problems. HIV-induced cognitive changes, although clinically very diverse are collectively called HIV-associated neurocognitive disorder (HAND). HAND, which until the introduction of cART manifested clinically as a subcortical disorder, is now considered primarily cognitive disorder, which makes it similar to diseases like Alzheimer's (AD) and Parkinson's disease (PD). The pathogenesis involves either the direct effects of the virus or the effect of viral proteins such as Tat, Ggp120, and Nef. These proteins are either capable of destroying neurons directly by inducing neurotoxic mediators or by initiating neuroinflammation by microglia and astrocytes. Recently, it has become recognized that HIV infection is associated with increased production of the beta-amyloid peptide (Aβ) which is a characteristic of AD. Moreover, amyloid plaques have also been demonstrated in the brains of patients suffering from HAND. Thus, the question arises whether this production of Aβ indicates that HAND may lead to AD or it is a form of AD or this increase in Aβ production is only a bystander effect. It has also been discovered that APP in HIV and its metabolic product Aβ in AD manifest antiviral innate immune peptide characteristics. This review attempts to bring together studies linking amyloid precursor protein (APP) and Aβ production in HIV infection and their possible impact on the course of HAND and AD. These data indicate that human defense mechanisms in HAND and AD are trying to contain microorganisms by antimicrobial peptides, however by employing different means. Future studies will, no doubt, uncover the relationship between HAND and AD and, hopefully, reveal novel treatment possibilities.
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Affiliation(s)
- Tamas Fulop
- Research Center on Aging, Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke, Quebec, J1H 5N4, Canada.
| | - Jacek M Witkowski
- Department of Pathophysiology, Medical University of Gdansk, Gdansk, Poland
| | - Anis Larbi
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Immunos Building, Biopolis, Singapore, Singapore.,Department of Biology, Faculty of Science, University Tunis El Manar, Tunis, Tunisia
| | - Abdelouahed Khalil
- Research Center on Aging, Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, University of Sherbrooke, 3001, 12th Avenue North, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Georges Herbein
- Department Pathogens & Inflammation-EPILAB, UPRES EA4266, Université of Franche-Comté (UFC), University of Bourgogne France-Comté (UBFC), F-25030, Besançon, France.,Department of Virology, CHRU Besancon, F-25030, Besancon, France
| | - Eric H Frost
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
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Hewel C, Kaiser J, Wierczeiko A, Linke J, Reinhardt C, Endres K, Gerber S. Common miRNA Patterns of Alzheimer's Disease and Parkinson's Disease and Their Putative Impact on Commensal Gut Microbiota. Front Neurosci 2019; 13:113. [PMID: 30890906 PMCID: PMC6411762 DOI: 10.3389/fnins.2019.00113] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/30/2019] [Indexed: 12/18/2022] Open
Abstract
With the rise of Next-Generation-Sequencing (NGS) methods, Micro-RNAs (miRNAs) have achieved an important position in the research landscape and have been found to present valuable diagnostic tools in various diseases such as multiple sclerosis or lung cancer. There is also emerging evidence that miRNAs play an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD) or Parkinson's disease (PD). Apparently, these diseases come along with changes in miRNA expression patterns which led to attempts from researchers to use these small RNA species from several body fluids for a better diagnosis and in order to observe disease progression. Additionally, it became evident that microbial commensals might play an important role for pathology development and were shown to have a significantly different composition in patients suffering from neurodegeneration compared with healthy controls. As it could recently be shown that secreted miRNAs are able to enter microbial organisms, it is conceivable that the host's miRNA might affect the gut microbial ecosystem. As such, miRNAs may inherit a central role in shaping the "diseased microbiome" and thereby mutually act on the characteristics of these neurodegenerative diseases. We have therefore (1) compiled a list of miRNAs known to be associated with AD and/or PD, (2) performed an in silico target screen for binding sites of these miRNA on human gut metagenome sequences and (3) evaluated the hit list for interesting matches potentially relevant to the etiology of AD and or PD. The examination of protein identifiers connected to bacterial secretion system, lipopolysaccharide biosynthesis and biofilm formation revealed an overlap of 37 bacterial proteins that were targeted by human miRNAs. The identified links of miRNAs to the biological processes of bacteria connected to AD and PD have yet to be validated via in vivo experiments. However, our results show a promising new approach for understanding aspects of these neurodegenerative diseases in light of the regulation of the microbiome.
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Affiliation(s)
- Charlotte Hewel
- Faculty of Biology, Institute for Developmental Biology and Neurobiology, Center of Computational Sciences Mainz (CSM), Johannes Gutenberg University Mainz, Mainz, Germany
| | - Julia Kaiser
- Faculty of Biology, Institute for Developmental Biology and Neurobiology, Center of Computational Sciences Mainz (CSM), Johannes Gutenberg University Mainz, Mainz, Germany
| | - Anna Wierczeiko
- Faculty of Biology, Institute for Developmental Biology and Neurobiology, Center of Computational Sciences Mainz (CSM), Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jan Linke
- Faculty of Biology, Institute for Developmental Biology and Neurobiology, Center of Computational Sciences Mainz (CSM), Johannes Gutenberg University Mainz, Mainz, Germany
| | - Christoph Reinhardt
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Susanne Gerber
- Faculty of Biology, Institute for Developmental Biology and Neurobiology, Center of Computational Sciences Mainz (CSM), Johannes Gutenberg University Mainz, Mainz, Germany
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Li H, Liu CC, Zheng H, Huang TY. Amyloid, tau, pathogen infection and antimicrobial protection in Alzheimer's disease -conformist, nonconformist, and realistic prospects for AD pathogenesis. Transl Neurodegener 2018; 7:34. [PMID: 30603085 PMCID: PMC6306008 DOI: 10.1186/s40035-018-0139-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/02/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a fatal disease that threatens the quality of life of an aging population at a global scale. Various hypotheses on the etiology of AD have been developed over the years to guide efforts in search of therapeutic strategies. MAIN BODY In this review, we focus on four AD hypotheses currently relevant to AD onset: the prevailing amyloid cascade hypothesis, the well-recognized tau hypothesis, the increasingly popular pathogen (viral infection) hypothesis, and the infection-related antimicrobial protection hypothesis. In briefly reviewing the main evidence supporting each hypothesis and discussing the questions that need to be addressed, we hope to gain a better understanding of the complicated multi-layered interactions in potential causal and/or risk factors in AD pathogenesis. As a defining feature of AD, the existence of amyloid deposits is likely fundamental to AD onset but is insufficient to wholly reproduce many complexities of the disorder. A similar belief is currently also applied to hyperphosphorylated tau aggregates within neurons, where tau has been postulated to drive neurodegeneration in the presence of pre-existing Aβ plaques in the brain. Although infection of the central nerve system by pathogens such as viruses may increase AD risk, it is yet to be determined whether this phenomenon is applicable to all cases of sporadic AD and whether it is a primary trigger for AD onset. Lastly, the antimicrobial protection hypothesis provides insight into a potential physiological role for Aβ peptides, but how Aβ/microbial interactions affect AD pathogenesis during aging awaits further validation. Nevertheless, this hypothesis cautions potential adverse effects in Aβ-targeting therapies by hindering potential roles for Aβ in anti-viral protection. CONCLUSION AD is a multi-factor complex disorder, which likely requires a combinatorial therapeutic approach to successfully slow or reduce symptomatic memory decline. A better understanding of how various causal and/or risk factors affecting disease onset and progression will enhance the likelihood of conceiving effective treatment paradigms, which may involve personalized treatment strategies for individual patients at varying stages of disease progression.
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Affiliation(s)
- Hongmei Li
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX USA
| | - Timothy Y. Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, San Diego, CA USA
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