51
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Guo T, Zhang D, Zeng Y, Huang TY, Xu H, Zhao Y. Molecular and cellular mechanisms underlying the pathogenesis of Alzheimer's disease. Mol Neurodegener 2020; 15:40. [PMID: 32677986 PMCID: PMC7364557 DOI: 10.1186/s13024-020-00391-7] [Citation(s) in RCA: 431] [Impact Index Per Article: 107.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 06/17/2020] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder seen in age-dependent dementia. There is currently no effective treatment for AD, which may be attributed in part to lack of a clear underlying mechanism. Studies within the last few decades provide growing evidence for a central role of amyloid β (Aβ) and tau, as well as glial contributions to various molecular and cellular pathways in AD pathogenesis. Herein, we review recent progress with respect to Aβ- and tau-associated mechanisms, and discuss glial dysfunction in AD with emphasis on neuronal and glial receptors that mediate Aβ-induced toxicity. We also discuss other critical factors that may affect AD pathogenesis, including genetics, aging, variables related to environment, lifestyle habits, and describe the potential role of apolipoprotein E (APOE), viral and bacterial infection, sleep, and microbiota. Although we have gained much towards understanding various aspects underlying this devastating neurodegenerative disorder, greater commitment towards research in molecular mechanism, diagnostics and treatment will be needed in future AD research.
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Affiliation(s)
- Tiantian Guo
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Denghong Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yuzhe Zeng
- Department of Orthopaedics, Orthopaedic Center of People's Liberation Army, The Affiliated Southeast Hospital of Xiamen University, Zhangzhou, China
| | - Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
| | - Yingjun Zhao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.
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52
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Huang Y, Cheng L, Turchinovich A, Mahairaki V, Troncoso JC, Pletniková O, Haughey NJ, Vella LJ, Hill AF, Zheng L, Witwer KW. Influence of species and processing parameters on recovery and content of brain tissue-derived extracellular vesicles. J Extracell Vesicles 2020; 9:1785746. [PMID: 32944174 PMCID: PMC7480582 DOI: 10.1080/20013078.2020.1785746] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Extracellular vesicles (EVs) are involved in a wide range of physiological and pathological processes by shuttling material out of and between cells. Tissue EVs may thus lend insights into disease mechanisms and also betray disease when released into easily accessed biological fluids. Since brain-derived EVs (bdEVs) and their cargo may serve as biomarkers of neurodegenerative diseases, we evaluated modifications to a published, rigorous protocol for separation of EVs from brain tissue and studied effects of processing variables on quantitative and qualitative outcomes. To this end, size exclusion chromatography (SEC) and sucrose density gradient ultracentrifugation were compared as final separation steps in protocols involving stepped ultracentrifugation. bdEVs were separated from brain tissues of human, macaque, and mouse. Effects of tissue perfusion and a model of post-mortem interval (PMI) before final bdEV separation were probed. MISEV2018-compliant EV characterization was performed, and both small RNA and protein profiling were done. We conclude that the modified, SEC-employing protocol achieves EV separation efficiency roughly similar to a protocol using gradient density ultracentrifugation, while decreasing operator time and, potentially, variability. The protocol appears to yield bdEVs of higher purity for human tissues compared with those of macaque and, especially, mouse, suggesting opportunities for optimization. Where possible, perfusion should be performed in animal models. The interval between death/tissue storage/processing and final bdEV separation can also affect bdEV populations and composition and should thus be recorded for rigorous reporting. Finally, different populations of EVs obtained through the modified method reported herein display characteristic RNA and protein content that hint at biomarker potential. To conclude, this study finds that the automatable and increasingly employed technique of SEC can be applied to tissue EV separation, and also reveals more about the importance of species-specific and technical considerations when working with tissue EVs. These results are expected to enhance the use of bdEVs in revealing and understanding brain disease.
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Affiliation(s)
- Yiyao Huang
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Andrey Turchinovich
- Molecular Epidemiology, German Cancer Research Center DKFZ, Heidelberg, Germany.,SciBerg e.Kfm, Mannheim, Germany
| | - Vasiliki Mahairaki
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Juan C Troncoso
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Olga Pletniková
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Norman J Haughey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Laura J Vella
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia.,Department of Surgery, The University of Melbourne, the Royal Melbourne Hospital, Parkville, Australia
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Lei Zheng
- Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Kenneth W Witwer
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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53
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Coneys R, Wood IC. Alzheimer's disease: the potential of epigenetic treatments and current clinical candidates. Neurodegener Dis Manag 2020; 10:543-558. [PMID: 32552286 DOI: 10.2217/nmt-2019-0034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease is a progressive and fatal neurodegenerative disease affecting 50 million people worldwide, characterized by memory loss and neuronal degeneration. Current treatments have limited efficacy and there is no cure. Alzheimer's is likely caused by a combination of factors, providing several potential therapeutic targets. One area of interest is the epigenetic regulation of gene expression within the brain. Epigenetic marks, including DNA methylation and histone modifications, show consistent changes with age and in those with Alzheimer's. Some epigenetic regulation has been linked to disease pathology and progression and are the focus of current research. Epigenetic regulators might make promising therapeutic targets yet challenges need to be overcome to generate an efficacious drug lacking deleterious side effects.
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Affiliation(s)
- Rachel Coneys
- Leonard Wolfson Experimental Neurology Centre, Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Ian C Wood
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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54
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Singh AK, Verma S. Use of ocular biomarkers as a potential tool for early diagnosis of Alzheimer's disease. Indian J Ophthalmol 2020; 68:555-561. [PMID: 32174567 PMCID: PMC7210832 DOI: 10.4103/ijo.ijo_999_19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/10/2019] [Accepted: 10/26/2019] [Indexed: 02/05/2023] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide which unfortunately has no known effective cure to date. Despite many clinical trials indicating the effectiveness of preclinical treatment, a sensitive tool for screening of AD is yet to be developed. Due to multiple similarities between ocular and the brain tissue, the eye is being explored by researchers for this purpose, with utmost attention focused on the retinal tissue. Besides visual functional impairment, neuronal degeneration and apoptosis, retinal nerve fiber degeneration, increase in the cup-to-disc ratio, and retinal vascular thinning and tortuosity are the changes observed in the retinal tissue which are related to AD. Studies have shown that targeting these changes in the retina is an effective way of reducing the degeneration of retinal neuronal tissue. Similar mechanisms of neurodegeneration have been demonstrated in the brain and the eyes of AD patients. Multiple studies are underway to investigate the potential of diagnosing AD and detection of amyloid-β (Aβ) levels in the retinal tissue. Since the tissues in the anterior segment of the eye are more accessible for in vivo imaging and examination, they have more potential as screening biomarkers. This article provides a concise review of available literature on the ocular biomarkers in anterior and posterior segments of the eye including the cornea, aqueous humour (AH), crystalline lens, and retina in AD. This review will also highlight the newer technological tools available for the detection of potential biomarkers in the eye for early diagnosis of AD.
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Affiliation(s)
- Ajay K Singh
- Consultant and Anterior Segment Surgeon, Department of Ophthalmology, Asian Institute of Medical Sciences, Faridabad, Haryana, India
| | - Shilpa Verma
- WNS Global Services Pvt. Ltd., Gurugram, Haryana, India
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55
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Cieślik M, Czapski GA, Wójtowicz S, Wieczorek I, Wencel PL, Strosznajder RP, Jaber V, Lukiw WJ, Strosznajder JB. Alterations of Transcription of Genes Coding Anti-oxidative and Mitochondria-Related Proteins in Amyloid β Toxicity: Relevance to Alzheimer's Disease. Mol Neurobiol 2020; 57:1374-1388. [PMID: 31734880 PMCID: PMC7061023 DOI: 10.1007/s12035-019-01819-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/23/2019] [Indexed: 12/17/2022]
Abstract
A growing body of evidence indicates that pathological forms of amyloid beta (Aβ) peptide contribute to neuronal degeneration and synaptic loss in Alzheimer's disease (AD). In this study, we investigated the impact of exogenous Aβ1-42 oligomers (AβO) and endogenously liberated Aβ peptides on transcription of genes for anti-oxidative and mitochondria-related proteins in cell lines (neuronal SH-SY5Y and microglial BV2) and in brain cortex of transgenic AD (Tg-AD) mice, respectively. Our results demonstrated significant AβO-evoked changes in transcription of genes in SH-SY5Y cells, where AβO enhanced expression of Sod1, Cat, mt-Nd1, Bcl2, and attenuated Sirt5, Sod2 and Sdha. In BV2 line, AβO increased the level of mRNA for Sod2, Dnm1l, Bcl2, and decreased for Gpx4, Sirt1, Sirt3, mt-Nd1, Sdha and Mfn2. Then, AβO enhanced free radicals level and impaired mitochondrial membrane potential only in SH-SY5Y cells, but reduced viability of both cell types. Inhibitor of poly(ADP-ribose)polymerase-1 and activator of sirtuin-1 more efficiently enhanced viability of SH-SY5Y than BV2 affected by AβO. Analysis of brain cortex of Tg-AD mice confirmed significant downregulation of Sirt1, Mfn1 and mt-Nd1 and upregulation of Dnm1l. In human AD brain, changes of microRNA pattern (miRNA-9, miRNA-34a, miRNA-146a and miRNA-155) seem to be responsible for decrease in Sirt1 expression. Overall, our results demonstrated a diverse response of neuronal and microglial cells to AβO toxicity. Alterations of genes encoding Sirt1, Mfn1 and Drp1 in an experimental model of AD suggest that modulation of mitochondria dynamics and Sirt1, including miRNA strategy, may be crucial for improvement of AD therapy.
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Affiliation(s)
- Magdalena Cieślik
- Department of Cellular Signaling, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland
| | - Grzegorz A Czapski
- Department of Cellular Signaling, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland
| | - Sylwia Wójtowicz
- Department of Cellular Signaling, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland
| | - Iga Wieczorek
- Laboratory of Preclinical Research and Environmental Agents, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland
| | - Przemysław L Wencel
- Laboratory of Preclinical Research and Environmental Agents, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland
| | - Robert P Strosznajder
- Laboratory of Preclinical Research and Environmental Agents, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland
| | - Vivian Jaber
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Walter J Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
- Bollinger Professor of Alzheimer's disease, LSU Neuroscience Center and Departments of Neurology and Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Joanna B Strosznajder
- Department of Cellular Signaling, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106, Warsaw, Poland.
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56
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Lee SY, Lu RB, Wang LJ, Chang CH, Lu T, Wang TY, Tsai KW. Serum miRNA as a possible biomarker in the diagnosis of bipolar II disorder. Sci Rep 2020; 10:1131. [PMID: 31980721 PMCID: PMC6981268 DOI: 10.1038/s41598-020-58195-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/13/2020] [Indexed: 12/19/2022] Open
Abstract
The diagnosis of Bipolar II disorder (BD-II) is currently based on the patients' description of symptoms and clinical behavioral observations. This study explored the possibility of miRNA in peripheral blood (serum) as a specific biomarker for BD-II. We identified 6 candidate miRNAs to differentiate BD-II patients from controls using next-generation sequencing. We then examined these candidate miRNAs using real-time PCR in the first cohort (as training group) of 79 BD-II and 95 controls. A diagnostic model was built based on these candidate miRNAs and then tested on an individual testing group (BD-II: n = 20, controls: n = 20). We found that serum expression levels of miR-7-5p, miR-23b-3p, miR-142-3p, miR-221-5p, and miR-370-3p significantly increased in BD-II compared with controls in the first cohort, whereas that of miR-145-5p showed no significant difference. The diagnostic power of the identified miRNAs was further analyzed using receiver-operating characteristic (ROC). Support vector machine (SVM) measurements revealed that a combination of the significant miRNAs reached good diagnostic accuracy (AUC: 0.907). We further examined an independent testing group and the diagnostic power reached fair for BD-II (specificity = 90%, sensitivity = 85%). We constructed miRNA panels using SVM model, which may aid in the diagnosis for BD-II.
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Affiliation(s)
- Sheng-Yu Lee
- Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.,Department of Psychiatry, College of Medicine, National Yang-Ming University, Taipei, Taiwan.,Department of Psychiatry, Faculty of Medicine, Kaohsiung Medical University Kaohsiung, Kaohsiung, Taiwan.,Department of Psychiatry, College of Medicine and Hospital, National Cheng Kung University, Tainan, Taiwan.,Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Ru-Band Lu
- Department of Psychiatry, College of Medicine and Hospital, National Cheng Kung University, Tainan, Taiwan.,Yanjiao Furen Hospital, Hebei, China
| | - Liang-Jen Wang
- Department of Child and Adolescent Psychiatry, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Cheng-Ho Chang
- Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Ti Lu
- Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Tzu-Yun Wang
- Department of Psychiatry, College of Medicine and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Kuo-Wang Tsai
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan. .,Department of Research, Taipei Tzu Chi Hospital, The Buddhist Tzu Chi Medical Foundation, New Taipei, Taiwan.
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57
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O’Meara T, Kong Y, Chiarella J, Price RW, Chaudhury R, Liu X, Spudich S, Robertson K, Emu B, Lu L. Exosomal MicroRNAs Associate With Neuropsychological Performance in Individuals With HIV Infection on Antiretroviral Therapy. J Acquir Immune Defic Syndr 2019; 82:514-522. [PMID: 31714431 PMCID: PMC6857839 DOI: 10.1097/qai.0000000000002187] [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] [Indexed: 02/06/2023]
Abstract
BACKGROUND Neurocognitive dysfunction remains prevalent among people living with HIV (PLWH), even after viral suppression on combination antiretroviral therapy (cART). We investigated associations between neuropsychological performance (NP) and patterns of circulating exosomal microRNA (exo-miRNA) expression in PLWH on cART. SETTING A cross-sectional examination of plasma exo-miRNA among PLWH on cART with systemic viral suppression and volunteers without HIV infection. METHODS Thirty-one PLWH who started cART during early infection (n = 19) or chronic infection (n = 12) participated in phlebotomy and an 11-test neuropsychological battery after >1 year on treatment. NP higher- or lower-performing participants were categorized based on normalized neuropsychological scores. Total RNA was extracted from purified exosomes of 31 PLWH and 5 volunteers without HIV and subject to small RNA sequencing. Differential expression of exo-miRNAs was examined and biological functions were predicted. RESULTS Eleven exo-miRNAs were up-regulated in NP lower-performing (n = 18) relative to higher-performing PLWH (n = 13). A high proportion of the differentiating exo-miRNA target the axon guidance KEGG pathway and neurotrophin tyrosine receptor kinase signaling Gene Ontology pathway. Differential expression analysis of exo-miRNAs between NP lower- (n = 7) and higher-performing (n = 12) PLWH within the early infection group alone confirmed largely consistent findings. CONCLUSIONS Plasma exo-miRNA content differed between NP higher- and lower-performing PLWH. Several differentially expressed exo-miRNAs were predicted to be involved in inflammation and neurodegeneration pathways. Exo-miRNA in plasma may indicate cross-talk between the circulation and central nervous system and thus may be clinically relevant for neurocognitive dysfunction in PLWH.
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Affiliation(s)
| | - Yong Kong
- Yale School of Public Health, New Haven, CT
| | | | - Richard W. Price
- University of California San Francisco School of Medicine,
San Francisco, CA
| | - Rabib Chaudhury
- Yale School of Engineering and Applied Sciences, New Haven,
CT
| | | | | | - Kevin Robertson
- University of North Carolina School of Medicine, Chapel
Hill, NC
| | | | - Lingeng Lu
- Yale School of Public Health, New Haven, CT
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58
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Lukiw WJ, Li W, Bond T, Zhao Y. Facilitation of Gastrointestinal (GI) Tract Microbiome-Derived Lipopolysaccharide (LPS) Entry Into Human Neurons by Amyloid Beta-42 (Aβ42) Peptide. Front Cell Neurosci 2019; 13:545. [PMID: 31866832 PMCID: PMC6908466 DOI: 10.3389/fncel.2019.00545] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 11/22/2019] [Indexed: 01/01/2023] Open
Abstract
Human gastrointestinal (GI)-tract microbiome-derived lipopolysaccharide (LPS): (i) has been recently shown to target, accumulate within, and eventually encapsulate neuronal nuclei of the human central nervous system (CNS) in Alzheimer's disease (AD) brain; and (ii) this action appears to impede and restrict the outward flow of genetic information from neuronal nuclei. It has previously been shown that in LPS-encased neuronal nuclei in AD brain there is a specific disruption in the output and expression of two AD-relevant, neuron-specific markers encoding the cytoskeletal neurofilament light (NF-L) chain protein and the synaptic phosphoprotein synapsin-1 (SYN1) involved in the regulation of neurotransmitter release. The biophysical mechanisms involved in the facilitation of the targeting of LPS to neuronal cells and nuclei and eventual nuclear envelopment and functional disruption are not entirely clear. In this "Perspectives article" we discuss current advances, and consider future directions in this research area, and provide novel evidence in human neuronal-glial (HNG) cells in primary culture that the co-incubation of LPS with amyloid-beta 42 (Aβ42) peptide facilitates the association of LPS with neuronal cells. These findings: (i) support a novel pathogenic role for Aβ42 peptides in neurons via the formation of pores across the nuclear membrane and/or a significant biophysical disruption of the neuronal nuclear envelope; and (ii) advance the concept that the Aβ42 peptide-facilitated entry of LPS into brain neurons, accession of neuronal nuclei, and down-regulation of neuron-specific components such as NF-L and SYN1 may contribute significantly to neuropathological deficits as are characteristically observed in AD-affected brain.
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Affiliation(s)
- Walter J. Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA, United States
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
- Department of Neurology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Wenhong Li
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA, United States
- Department of Pharmacology, School of Pharmacy, Jiangxi University of Traditional Chinese Medicine (TCM), Nanchang, China
| | - Taylor Bond
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA, United States
- Department of Anatomy and Cell Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
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59
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Litwińska Z, Sobuś A, Łuczkowska K, Grabowicz A, Mozolewska-Piotrowska K, Safranow K, Kawa MP, Machaliński B, Machalińska A. The Interplay Between Systemic Inflammatory Factors and MicroRNAs in Age-Related Macular Degeneration. Front Aging Neurosci 2019; 11:286. [PMID: 31695606 PMCID: PMC6817913 DOI: 10.3389/fnagi.2019.00286] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/04/2019] [Indexed: 12/20/2022] Open
Abstract
We aimed to explore the expression of systemic inflammatory factors and selected intracellular miRNAs that regulate inflammatory signaling pathways potentially involved in age-related macular degeneration (AMD) pathogenesis. A total of 179 patients with wet AMD, 175 with dry AMD and 121 controls were enrolled in the study. Soluble inflammatory factors were analyzed in plasma samples using Luminex technology. Expression of selected miRNAs was analyzed in isolated nucleated peripheral blood cells (PBNCs) using real-time qPCR. Wet AMD was an independent factor associated with higher concentrations of IL-6 (β = +0.24, p = 0.0004), GM-CSF (β = +0.31, p < 0.001), IFN-γ (β = +0.58, p < 0.001), higher expression of miRNA-23a-3p (β = +0.60, p < 0.0001), miRNA-30b (β = +0.32, p < 0.0001), miRNA-191-5p (β = +0.28, p < 0.0001) and lower concentration of IL-1β (β = −0.25, p = 0.0003), IL-5 (β = −0.45, p < 0.001), IL-10 (β = −0.45, p < 0.001), IL-12 (β = −0.35, p < 0.001), lower expression of miRNA-16-5p (β = −0.31, p < 0.0001), miRNA-17-3p (β = −0.18, p = 0.01), miRNA-150-5p (β = −0.18, p = 0.01) and miRNA-155-5p (β = −0.47, p < 0.0001). Multivariate analysis revealed that dry AMD was an independent factor associated with higher concentration of GM-CSF (β = +0.34, p < 0.001), IL-6 (β = +0.13, p = 0.05), higher expression of miRNA-23a-3p (β = +0.60, p < 0.0001), miRNA-126-3p (β = +0.23, p = 0.0005), miRNA-126-5p (β = +0.16, p = 0.01), miRNA 146a (β = +0.14, p = 0.03), and mRNA191-5p (β = +0.15, p = 0.03) and lower concentrations of TNF-α (β = +0.24, p = 0.0004), IL-1β (β = −0.39, p < 0.001), IL-2 (β = −0.20, p = 0.003), IL-5 (β = −0.54, p < 0.001), IL-10 (β = −0.56, p < 0.001), IL-12 (β = −0.51, p < 0.001), lower expression of miRNA-16-5p (β = −0.23, p = 0.0004), miRNA-17-3p (β = −0.20, p = 0.003) and miRNA-17-5p (β = −0.19, p = 0.004). Negative correlations between visual acuity and WBC, lymphocyte count, TNF-α, IL-1 β, IL-2, IL-4, IL-6, IL-10 concentrations and miRNA-191-5p, as well as positive correlations between visual acuity and miRNA-126-3p, -126-5p, and -155-5p PBNCs expression were found in AMD patients. No such correlations were found in the control group. Our results may suggest the role of both intra- and extracellular mechanisms implicated in inflammatory response regulation in multifactorial AMD pathogenesis.
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Affiliation(s)
- Zofia Litwińska
- Department of General Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Anna Sobuś
- Department of General Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Karolina Łuczkowska
- Department of General Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Aleksandra Grabowicz
- First Department of Ophthalmology, Pomeranian Medical University, Szczecin, Poland
| | | | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin, Poland
| | - Miłosz Piotr Kawa
- Department of General Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Bogusław Machaliński
- Department of General Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Anna Machalińska
- First Department of Ophthalmology, Pomeranian Medical University, Szczecin, Poland
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60
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Nuzziello N, Liguori M. The MicroRNA Centrism in the Orchestration of Neuroinflammation in Neurodegenerative Diseases. Cells 2019; 8:cells8101193. [PMID: 31581723 PMCID: PMC6829202 DOI: 10.3390/cells8101193] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 12/11/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs with a unique ability to regulate the transcriptomic profile by binding to complementary regulatory RNA sequences. The ability of miRNAs to enhance (proinflammatory miRNAs) or restrict (anti-inflammatory miRNAs) inflammatory signalling within the central nervous system is an area of ongoing research, particularly in the context of disorders that feature neuroinflammation, including neurodegenerative diseases (NDDs). Furthermore, the discovery of competing endogenous RNAs (ceRNAs) has led to an increase in the complexity of miRNA-mediated gene regulation, with a paradigm shift from a unidirectional to a bidirectional regulation, where miRNA acts as both a regulator and is regulated by ceRNAs. Increasing evidence has revealed that ceRNAs, including long non-coding RNAs, circular RNAs, and pseudogenes, can act as miRNA sponges to regulate neuroinflammation in NDDs within complex cross-talk regulatory machinery, which is referred to as ceRNA network (ceRNET). In this review, we discuss the role of miRNAs in neuroinflammatory regulation and the manner in which cellular and vesicular ceRNETs could influence neuroinflammatory dynamics in complex multifactorial diseases, such as NDDs.
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Affiliation(s)
- Nicoletta Nuzziello
- National Research Council, Institute of Biomedical Technologies, Bari Unit, 70126 Bari, Italy.
| | - Maria Liguori
- National Research Council, Institute of Biomedical Technologies, Bari Unit, 70126 Bari, Italy.
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61
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Deng C, Naler LB, Lu C. Microfluidic epigenomic mapping technologies for precision medicine. LAB ON A CHIP 2019; 19:2630-2650. [PMID: 31338502 PMCID: PMC6697104 DOI: 10.1039/c9lc00407f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Epigenomic mapping of tissue samples generates critical insights into genome-wide regulations of gene activities and expressions during normal development and disease processes. Epigenomic profiling using a low number of cells produced by patient and mouse samples presents new challenges to biotechnologists. In this review, we first discuss the rationale and premise behind profiling epigenomes for precision medicine. We then examine the existing literature on applying microfluidics to facilitate low-input and high-throughput epigenomic profiling, with emphasis on technologies enabling interfacing with next-generation sequencing. We detail assays on studies of histone modifications, DNA methylation, 3D chromatin structures and non-coding RNAs. Finally, we discuss what the future may hold in terms of method development and translational potential.
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Affiliation(s)
- Chengyu Deng
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
| | - Lynette B Naler
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
| | - Chang Lu
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA.
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62
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Chen JJ, Yang G, Yan QQ, Zhao J, Li S. Exosome-encapsulated microRNAs as promising biomarkers for Alzheimer’s disease. Rev Neurosci 2019; 31:77-87. [DOI: 10.1515/revneuro-2019-0001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/17/2019] [Indexed: 12/13/2022]
Abstract
Abstract
Alzheimer’s disease (AD) is a chronic neurodegenerative disease that locks into long clinical latency and low curative ratio. Therefore, early diagnosis before the clinical phase is quite essential and may be effective for therapeutic prevention. Peripheral blood or cerebrospinal fluid biomarkers symbolizing functional neuronal impairment are gradually applied to diagnose AD in research studies. Exosomes have generated immense interest in the diagnosis field of neurodegenerative disorders after confirmation of their roles as mediators, delivering important proteins and microRNAs (miRNAs) in intercellular communication. Compelling research results reveal that miRNAs released from exosomes modulate expression and function of amyloid precursor proteins and tau proteins. These findings open up possibility that dysfunctional exosomal miRNAs may influence AD progression. In this review, we summarized the existing knowledge of exosomal miRNAs and their involvement in AD, emphasizing their potential to serve as diagnostic biomarkers during the preclinical phase of AD.
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Affiliation(s)
- Jian-jiao Chen
- Department of General Surgery , Jinhua Hospital of Zhejiang University (Jinhua Municipal Central Hospital) , Jinhua City 321000, Zhejiang Province , P.R. China
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University , Dalian City 116044, Liaoning Province , P.R. China
| | - Guang Yang
- Hepatic Surgery Center, Tongji Hospital, Tongji Medical College , Huazhong University of Science and Technology , Wuhan City 430030, Hubei Province , P.R. China
| | - Qing-qing Yan
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences , Dalian Medical University , 9 Western District, Lvshun South Road, Dalian City 116044 , Liaoning Province , P.R. China
| | - Jie Zhao
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences , Dalian Medical University , 9 Western District, Lvshun South Road, Dalian City 116044 , Liaoning Province , P.R. China
- National-Local Joint Engineering Research Center for Drug-Research and Development (R&D) of Neurodegenerative Diseases , Dalian Medical University , Dalian 116000 , China
| | - Shao Li
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences , Dalian Medical University , 9 Western District, Lvshun South Road, Dalian City 116044 , Liaoning Province , P.R. China
- National-Local Joint Engineering Research Center for Drug-Research and Development (R&D) of Neurodegenerative Diseases , Dalian Medical University , Dalian 116000 , China
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63
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Herrera-Espejo S, Santos-Zorrozua B, Álvarez-González P, Lopez-Lopez E, Garcia-Orad Á. A Systematic Review of MicroRNA Expression as Biomarker of Late-Onset Alzheimer's Disease. Mol Neurobiol 2019; 56:8376-8391. [PMID: 31240600 DOI: 10.1007/s12035-019-01676-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 06/09/2019] [Indexed: 12/11/2022]
Abstract
Late-onset Alzheimer's disease (LOAD) is a high-occurrence neurological disorder but the difficulty in identifying precise and early biomarkers has complicated the understanding of the disease and the development of new treatments. In this sense, important knowledge is emerging regarding novel molecular and biological candidates with diagnostic potential, including microRNAs (miRNAs), which have a key role in gene repression. The aim of this systematic review was to define the role of miRNAs' expression as biomarkers for LOAD both in brain tissues, which could help understand the biology of the disease, and circulating tissues, which could serve as non-invasive markers of the pathology. A systematic search was performed in Web of Science and PubMed using the keywords ((Alzheimer or Alzheimer's) and (microRNA or microRNAs or miRNA or miRNAs or miR)) until August 2018 to retrieve all articles that presented independent original data evaluating the impact of miRNA expression on the development of LOAD in human population. A total of 90 studies investigating the role of miRNAs' expression in the development of LOAD were identified. While other widely studied miRNAs such as hsa-miR-146a presented contradictory results among studies, deregulation in brain tissue of seven miRNAs, hsa-miR-16-5p, hsa-miR-34a-5p, hsa-miR-107, hsa-miR-125-5p, hsa-miR-132-3p, hsa-miR-181-3p, and hsa-miR-212-3p, was consistently identified in LOAD patients. Their role in the disease could be mediated through the regulation of key pathways, such as axon guidance, longevity, insulin, and MAPK signaling pathway. However, regarding their role as non-invasive biomarkers of LOAD in fluids, although the limited results available are promising, further studies are required.
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Affiliation(s)
- Soraya Herrera-Espejo
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Medicine and Nursing, University of The Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
| | - Borja Santos-Zorrozua
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Medicine and Nursing, University of The Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
| | - Paula Álvarez-González
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Medicine and Nursing, University of The Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
| | - Elixabet Lopez-Lopez
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Medicine and Nursing, University of The Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain.
- BioCruces Bizkaia Health Research Institute, Barakaldo, Spain.
| | - África Garcia-Orad
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Medicine and Nursing, University of The Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940, Leioa, Spain
- BioCruces Bizkaia Health Research Institute, Barakaldo, Spain
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64
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Hu Z, Lv X, Chen L, Gu X, Qian H, Fransisca S, Zhang Z, Liu Q, Xie P. Protective effects of microRNA‐22‐3p against retinal pigment epithelial inflammatory damage by targeting NLRP3 inflammasome. J Cell Physiol 2019; 234:18849-18857. [PMID: 30927257 DOI: 10.1002/jcp.28523] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 02/25/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Zizhong Hu
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Xuehua Lv
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
- Department of Ophthalmology Children's Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Lu Chen
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Xunyi Gu
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Huiming Qian
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Silvia Fransisca
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Zhengyu Zhang
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Qinghuai Liu
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
| | - Ping Xie
- Department of Ophthalmology The First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China
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65
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Zhao Y, Jaber VR, LeBeauf A, Sharfman NM, Lukiw WJ. microRNA-34a (miRNA-34a) Mediated Down-Regulation of the Post-synaptic Cytoskeletal Element SHANK3 in Sporadic Alzheimer's Disease (AD). Front Neurol 2019; 10:28. [PMID: 30792687 PMCID: PMC6374620 DOI: 10.3389/fneur.2019.00028] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/10/2019] [Indexed: 12/13/2022] Open
Abstract
Integrating a combination of bioinformatics, microRNA microfluidic arrays, ELISA analysis, LED Northern, and transfection-luciferase reporter assay data using human neuronal-glial (HNG) cells in primary culture we have discovered a set of up-regulated microRNAs (miRNAs) linked to a small family of down-regulated messenger RNAs (mRNAs) within the superior temporal lobe neocortex (Brodmann A22) of sporadic Alzheimer's disease (AD) brain. At the level of mRNA abundance, the expression of a significant number of human brain genes found to be down-regulated in sporadic AD neocortex appears to be due to the increased abundance of a several brain-abundant inducible miRNAs. These up-regulated miRNAs—including, prominently, miRNA-34a—have complimentary RNA sequences in the 3′ untranslated-region (3′-UTR) of their target-mRNAs that results in the pathological down-regulation in the expression of important brain genes. An up-regulated microRNA-34a, already implicated in age-related inflammatory-neurodegeneration–appears to down-regulate key mRNA targets involved in synaptogenesis and synaptic-structure, distinguishing neuronal deficits associated with AD neuropathology. One significantly down-regulated post-synaptic element in AD is the proline-rich SH3 and multiple-ankyrin-repeat domain SHANK3 protein. Bioinformatics, microRNA array analysis and SHANK3-mRNA-3′UTR luciferase-reporter assay confirmed the importance of miRNA-34a in the regulation of SHANK3 expression in HNG cells. This paper reports on recent studies of a miRNA-34a-up-regulation coupled to SHANK3 mRNA down-regulation in sporadic AD superior-temporal lobe compared to age-matched controls. These findings further support our hypothesis of an altered miRNA-mRNA coupled signaling network in AD, much of which is supported, and here reviewed, by recently reported experimental-findings in the scientific literature.
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Affiliation(s)
- Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States.,Department of Anatomy and Cell Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Vivian R Jaber
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
| | - Ayrian LeBeauf
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
| | - Nathan M Sharfman
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
| | - Walter J Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States.,Department of Ophthalmology, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States.,Department of Neurology, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
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66
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The Role of Ceramide and Sphingosine-1-Phosphate in Alzheimer's Disease and Other Neurodegenerative Disorders. Mol Neurobiol 2019; 56:5436-5455. [PMID: 30612333 PMCID: PMC6614129 DOI: 10.1007/s12035-018-1448-3] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 12/06/2018] [Indexed: 12/11/2022]
Abstract
Bioactive sphingolipids-ceramide, sphingosine, and their respective 1-phosphates (C1P and S1P)-are signaling molecules serving as intracellular second messengers. Moreover, S1P acts through G protein-coupled receptors in the plasma membrane. Accumulating evidence points to sphingolipids' engagement in brain aging and in neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases and amyotrophic lateral sclerosis. Metabolic alterations observed in the course of neurodegeneration favor ceramide-dependent pro-apoptotic signaling, while the levels of the neuroprotective S1P are reduced. These trends are observed early in the diseases' development, suggesting causal relationship. Mechanistic evidence has shown links between altered ceramide/S1P rheostat and the production, secretion, and aggregation of amyloid β/α-synuclein as well as signaling pathways of critical importance for the pathomechanism of protein conformation diseases. Sphingolipids influence multiple aspects of Akt/protein kinase B signaling, a pathway that regulates metabolism, stress response, and Bcl-2 family proteins. The cross-talk between sphingolipids and transcription factors including NF-κB, FOXOs, and AP-1 may be also important for immune regulation and cell survival/death. Sphingolipids regulate exosomes and other secretion mechanisms that can contribute to either the spread of neurotoxic proteins between brain cells, or their clearance. Recent discoveries also suggest the importance of intracellular and exosomal pools of small regulatory RNAs in the creation of disturbed signaling environment in the diseased brain. The identified interactions of bioactive sphingolipids urge for their evaluation as potential therapeutic targets. Moreover, the early disturbances in sphingolipid metabolism may deliver easily accessible biomarkers of neurodegenerative disorders.
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67
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Cong L, Zhao Y, Pogue AI, Lukiw WJ. Role of microRNA (miRNA) and Viroids in Lethal Diseases of Plants and Animals. Potential Contribution to Human Neurodegenerative Disorders. BIOCHEMISTRY (MOSCOW) 2018; 83:1018-1029. [PMID: 30472940 DOI: 10.1134/s0006297918090031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Both plants and animals have adopted a common strategy of using ~18-25-nucleotide small non-coding RNAs (sncRNAs), known as microRNAs (miRNAs), to transmit DNA-based epigenetic information. miRNAs (i) shape the total transcriptional output of individual cells; (ii) regulate and fine-tune gene expression profiles of cell clusters, and (iii) modulate cell phenotype in response to environmental stimuli and stressors. These miRNAs, the smallest known carriers of gene-encoded post-transcriptional regulatory information, not only regulate cellular function in healthy cells but also act as important mediators in the development of plant and animal diseases. Plants possess their own specific miRNAs; at least 32 plant species have been found to carry infectious sncRNAs called viroids, whose mechanisms of generation and functions are strikingly similar to those of miRNAs. This review highlights recent remarkable and sometimes controversial findings in miRNA signaling in plants and animals. Special attention is given to the intriguing possibility that dietary miRNAs and/or sncRNAs can function as mobile epigenetic and/or evolutionary linkers between different species and contribute to both intra- and interkingdom signaling. Wherever possible, emphasis has been placed on the relevance of these miRNAs to the development of human neurodegenerative diseases, such as Alzheimer's disease. Based on the current available data, we suggest that such xeno-miRNAs may (i) contribute to the beneficial properties of medicinal plants, (ii) contribute to the negative properties of disease-causing or poisonous plants, and (iii) provide cross-species communication between kingdoms of living organisms involving multiple epigenetic and/or potentially pathogenic mechanisms associated with the onset and pathogenesis of various diseases.
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Affiliation(s)
- L Cong
- Neuroscience Center, Louisiana State University School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112-2272, USA.,Department of Neurology, Shengjing Hospital, China Medical University, Heping District, Shenyang, Liaoning Province, China
| | - Y Zhao
- Neuroscience Center, Louisiana State University School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112-2272, USA.,Department of Anatomy and Cell Biology, Louisiana State University School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112-2272, USA
| | - A I Pogue
- Alchem Biotech Research, Toronto, ON M5S 1A8, Canada
| | - W J Lukiw
- Neuroscience Center, Louisiana State University School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112-2272, USA. .,Department Neurology, Louisiana State University School of Medicine, New Orleans, LA 70112-2272, USA.,Department Ophthalmology, Louisiana State University School of Medicine, New Orleans, LA 70112-2272, USA
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68
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Liu X, Jiao B, Shen L. The Epigenetics of Alzheimer's Disease: Factors and Therapeutic Implications. Front Genet 2018; 9:579. [PMID: 30555513 PMCID: PMC6283895 DOI: 10.3389/fgene.2018.00579] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/08/2018] [Indexed: 02/05/2023] Open
Abstract
Alzheimer’s disease (AD) is a well-known neurodegenerative disorder that imposes a great burden on the world. The mechanisms of AD are not yet fully understood. Current insight into the role of epigenetics in the mechanism of AD focuses on DNA methylation, remodeling of chromatin, histone modifications and non-coding RNA regulation. This review summarizes the current state of knowledge regarding the role of epigenetics in AD and the possibilities for epigenetically based therapeutics. The general conclusion is that epigenetic mechanisms play a variety of crucial roles in the development of AD, and there are a number of viable possibilities for treatments based on modulating these effects, but significant advances in knowledge and technology will be needed to move these treatments from the bench to the bedside.
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Affiliation(s)
- Xiaolei Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Bin Jiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, China
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69
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Desmettre T. [Epigenetics in age-related macular degeneration (AMD) - French translation of the article]. J Fr Ophtalmol 2018; 41:981-990. [PMID: 30454959 DOI: 10.1016/j.jfo.2018.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/02/2018] [Accepted: 06/07/2018] [Indexed: 02/02/2023]
Abstract
Age-related macular degeneration (AMD) is a complex multifactorial condition involving multiple genetic, environmental and constitutional factors. Inflammation, oxidative stress and lipid metabolism seem to be the most important factors in the pathogenesis of the disease. The importance of genetic factors has mainly been revealed with the influence of histocompatibility complement factor H (CFH) variations and the ARSM2 susceptibility gene. Another component, epigenetics, could help to explain some of the relationships between environmental and genetic factors. Epigenetics is defined as the study of modulations of gene activity that can be transmitted over cell divisions without involving mutation of the DNA sequence. The molecules that are involved in these mechanisms are referred to as the epigenome. The mechanisms involve DNA methylation, histone modification, chromatin remodeling, and gene inhibition by non-coding RNA. Epigenetics could explain how the environment may induce relatively stable changes in traits or even diseases, possibly inheritable over several generations. Epigenetic traits established during development, and/or acquired under the influence of nutritional factors or other environmental factors, could influence the interactions between genes and the environment. Several authors have recently shown the influence of epigenetic factors in the pathogenesis of ocular diseases such as cataract, dry eye, glaucoma, diabetic retinopathy and more recently AMD. A better understanding of the involvement of genetic variants at risk, their relationship with epigenetics and environmental factors would certainly help to better assess the risk of developing AMD or better understand recent changes in the incidence of the disease.
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Affiliation(s)
- T Desmettre
- Centre de rétine médicale, 187, rue de Menin, 59520 Marquette-Lez-Lille, France; London International Medical Centre, 18-22 Queen Anne Street, London, W1G 8HU, Royaume-Uni.
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70
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Abstract
PURPOSE OF REVIEW To explore the most recent developments in the effective diagnosis and treatment of neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). RECENT FINDINGS The clinical diagnosis of NPS in AD is facilitated by the use of the Neuropsychiatric Inventory (NPI). CT and MRI scans can be useful for detecting structural changes indicating AD. Other promising diagnostic methodologies that are less frequently used in the clinical setting include positron emission tomography (PET) scans for detecting amyloid and blood tests for detecting serum biomarkers. Numerous pharmaceutical agents have been studied for their use in managing NPS, with antipsychotics being popular for managing agitation but also having significant side effects. Non-pharmacological interventions, such as reminiscence therapy and the Describe, Investigate, Create, Evaluate (DICE) approach may be able to provide treatment without such adverse effects. Diagnosing AD and the comorbid NPS remains primarily a clinical endeavor with CT and MRI scans sometimes used, but evidence is amassing for the use of other imaging modalities and different lab tests for convenient and empiric diagnosis of AD to distinguish it from other psychiatric illnesses. The number of pharmacologic treatments for NPS that are safe as well as efficacious remains limited, yet non-pharmacologic interventions have clear clinical utility. In addition to searching for more successful pharmacological treatments, further research should focus on novel diagnostic tests and non-pharmacologic therapies.
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Affiliation(s)
- David Wolinsky
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
| | - Karina Drake
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA.
| | - Jolene Bostwick
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
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71
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Desmettre TJ. Epigenetics in Age-related Macular Degeneration (AMD). J Fr Ophtalmol 2018; 41:e407-e415. [PMID: 30458925 DOI: 10.1016/j.jfo.2018.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 09/04/2018] [Indexed: 01/03/2023]
Abstract
Age-related Macular Degeneration (AMD) is a complex multifactorial condition involving multiple genetic, environmental and constitutional factors. Inflammation, oxidative stress and lipid metabolism seem to be the most important factors in the pathogenesis of the disease. The importance of genetic factors has mainly been revealed with the influence of histocompatibility complement factor H (CFH) variations and the ARSM2 susceptibility gene. Another component, epigenetics, could help to explain some of the relationships between environmental and genetic factors. Epigenetics is defined as the study of modulations of gene activity that can be transmitted over cell divisions without involving mutation of the DNA sequence. The molecules that are involved in these mechanisms are referred to as the epigenome. The mechanisms involve DNA methylation, histone modification, chromatin remodeling, and gene inhibition by non-coding RNA. Epigenetics could explain how the environment may induce relatively stable changes in traits or even diseases, possibly inheritable over several generations. Epigenetic traits established during development, and/or acquired under the influence of nutritional factors or other environmental factors, could influence the interactions between genes and the environment. Several authors have recently shown the influence of epigenetic factors in the pathogenesis of ocular diseases such as cataract, dry eye, glaucoma, diabetic retinopathy and more recently AMD. A better understanding of the involvement of genetic variants at risk, their relationship with epigenetics and environmental factors would certainly help to better assess the risk of developing AMD or better understand recent changes in the incidence of the disease.
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Affiliation(s)
- T J Desmettre
- Centre de rétine médicale, 187, rue de Menin, 59520 Marquette-Lez-Lille, France; London International Medical Centre, 18-22 Queen Anne Street, London, W1G 8HU, United Kingdom.
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72
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Jun S, Datta S, Wang L, Pegany R, Cano M, Handa JT. The impact of lipids, lipid oxidation, and inflammation on AMD, and the potential role of miRNAs on lipid metabolism in the RPE. Exp Eye Res 2018; 181:346-355. [PMID: 30292489 DOI: 10.1016/j.exer.2018.09.023] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/31/2018] [Accepted: 09/30/2018] [Indexed: 12/17/2022]
Abstract
The accumulation of lipids within drusen, the epidemiologic link of a high fat diet, and the identification of polymorphisms in genes involved in lipid metabolism that are associated with disease risk, have prompted interest in the role of lipid abnormalities in AMD. Despite intensive investigation, our understanding of how lipid abnormalities contribute to AMD development remains unclear. Lipid metabolism is tightly regulated, and its dysregulation can trigger excess lipid accumulation within the RPE and Bruch's membrane. The high oxidative stress environment of the macula can promote lipid oxidation, impairing their original function as well as producing oxidation-specific epitopes (OSE), which unless neutralized, can induce unwanted inflammation that additionally contributes to AMD progression. Considering the multiple layers of lipid metabolism and inflammation, and the ability to simultaneously target multiple pathways, microRNA (miRNAs) have emerged as important regulators of many age-related diseases including atherosclerosis and Alzheimer's disease. These diseases have similar etiologic characteristics such as lipid-rich deposits, oxidative stress, and inflammation with AMD, which suggests that miRNAs might influence lipid metabolism in AMD. In this review, we discuss the contribution of lipids to AMD pathobiology and introduce how miRNAs might affect lipid metabolism during lesion development. Establishing how miRNAs contribute to lipid accumulation in AMD will help to define the role of lipids in AMD, and open new treatment avenues for this enigmatic disease.
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Affiliation(s)
- Sujung Jun
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Sayantan Datta
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Lei Wang
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Roma Pegany
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - Marisol Cano
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States
| | - James T Handa
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, MD, 21287, United States.
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73
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Wubben TJ, Besirli CG, Johnson MW, Zacks DN. Retinal Neuroprotection: Overcoming the Translational Roadblocks. Am J Ophthalmol 2018; 192:xv-xxii. [PMID: 29702074 DOI: 10.1016/j.ajo.2018.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/13/2018] [Accepted: 04/13/2018] [Indexed: 11/25/2022]
Abstract
PURPOSE To elucidate the issues that have prevented successful translation of neuroprotective therapeutic modalities for retinal disease from the preclinical to the clinical realm and to suggest strategies to circumvent these barriers in order to develop novel treatments to prevent vision loss. DESIGN Interpretive essay. METHODS Review and synthesis of selected reports of neuroprotective approaches for retinal disease, with interpretation and perspective. RESULTS Retinal neuroprotection is defined as any measure that reduces the death of retinal cells or axonal extensions into the optic nerve, and there is a great unmet need for such therapeutic modalities. Despite encouraging preclinical data, the translation of neuroprotective therapies to the clinic has been fraught with failure. Fundamental issues that have plagued this transition include the animal models used in preclinical studies, the reproducibility of the preclinical data, and the choice of meaningful clinical trial endpoints. Developing animal models that more aptly mimic human disease, defining a set of guidelines for preclinical evaluation of neuroprotective therapies in retinal disease, and identifying and validating biomarkers as surrogate clinical endpoints that shorten and optimize drug development timelines may circumvent some of these barriers to translation. CONCLUSIONS Neuroprotective therapeutic approaches have the potential to prevent vision loss in millions of people affected with eye diseases worldwide. However, a stigma currently accompanies the concept of neuroprotection because of the many past failures to bridge the gap between the preclinical and clinical realms. Understanding and addressing the fundamental reasons for the failure of translatable research provides hope for the future development of neuroprotective therapies.
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Colligris P, Perez de Lara MJ, Colligris B, Pintor J. Ocular Manifestations of Alzheimer's and Other Neurodegenerative Diseases: The Prospect of the Eye as a Tool for the Early Diagnosis of Alzheimer's Disease. J Ophthalmol 2018; 2018:8538573. [PMID: 30151279 PMCID: PMC6091327 DOI: 10.1155/2018/8538573] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 12/20/2022] Open
Abstract
Dementia, including Alzheimer's disease (AD), is a major disorder, leading to several ocular manifestations amongst the elderly population. These visual disorders may be due to retinal nerve degenerative changes, including nerve fibre layer thinning, degeneration of retinal ganglion cells, and changes to vascular parameters. There is no cure for Alzheimer's, but medicines can slow down the development of many of the classic symptoms, such as loss of memory and communication skills, mood swings, and depression. The disease diagnosis is difficult, and it is only possible through PET scans of the brain, detecting evidence of the accumulation of amyloid and tau. PET is expensive and invasive, requiring the injection of radioactive tracers, which bind with these proteins and glow during scanning. Recently, scientists developed promising eye-scan techniques that may detect Alzheimer's disease at its earliest stage, before major symptoms appear, leading to improved management of the disease symptoms. In this review, we are discussing the visual abnormalities of Alzheimer's and other neurodegenerative diseases, focused on ocular functional-visual-structural biomarkers, retinal pathology, and potential novel diagnostic tools.
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Affiliation(s)
- Pade Colligris
- Universidad Alfonso X, Madrid, Spain
- Ocupharm Diagnostics SL, Madrid, Spain
| | | | - Basilio Colligris
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
| | - Jesus Pintor
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
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Zhao Y, Lukiw WJ. Bacteroidetes Neurotoxins and Inflammatory Neurodegeneration. Mol Neurobiol 2018; 55:9100-9107. [PMID: 29637444 DOI: 10.1007/s12035-018-1015-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/16/2018] [Indexed: 12/31/2022]
Abstract
The gram-negative facultative anaerobe Bacteroides fragilis (B. fragilis) constitutes an appreciable proportion of the human gastrointestinal (GI)-tract microbiome. As is typical of most gram-negative bacilli, B. fragilis secretes an unusually complex mixture of neurotoxins including the extremely pro-inflammatory lipopolysaccharide BF-LPS. LPS (i) has recently been shown to associate with the periphery of neuronal nuclei in sporadic Alzheimer's disease (AD) brain and (ii) promotes the generation of the inflammatory transcription factor NF-kB (p50/p65 complex) in human neuronal-glial cells in primary-culture. In turn, the NF-kB (p50/p65 complex) strongly induces the transcription of a small family of pro-inflammatory microRNAs (miRNAs) including miRNA-9, miRNA-34a, miRNA-125b, miRNA-146a, and miRNA-155. These ultimately bind with the 3'-untranslated region (3'-UTR) of several target messenger RNAs (mRNAs) and thereby reduce their expression. Down-regulated mRNAs include those encoding complement factor-H (CFH), an SH3-proline-rich multi-domain-scaffolding protein of the postsynaptic density (SHANK3), and the triggering receptor expressed in myeloid/microglial cells (TREM2), as is observed in sporadic AD brain. Hence, a LPS normally confined to the GI tract is capable of driving a NF-kB-miRNA-mediated deficiency in gene expression that contributes to alterations in synaptic-architecture and synaptic-deficits, amyloidogenesis, innate-immune defects, and progressive inflammatory signaling, all of which are characteristics of AD-type neurodegeneration. This article will review the most recent research which supports the idea that bacterial components of the GI tract microbiome such as BF-LPS can transverse biophysical barriers and contribute to AD-type change. For the first-time, these results indicate that specific GI tract microbiome-derived neurotoxins have a strong pathogenic role in eliciting alterations in NF-kB-miRNA-directed gene expression that drives the AD process.
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Affiliation(s)
- Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans, LA, 70112, USA.,Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans, LA, 70112, USA
| | - Walter J Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans, LA, 70112, USA. .,Department of Neurology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans, LA, 70112, USA. .,Departments of Ophthalmology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans, LA, 70112, USA.
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Zhao Y, Lukiw WJ. Microbiome-Mediated Upregulation of MicroRNA-146a in Sporadic Alzheimer's Disease. Front Neurol 2018; 9:145. [PMID: 29615954 PMCID: PMC5867462 DOI: 10.3389/fneur.2018.00145] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
The first indication of a potential mechanistic link between the pathobiology of the human gastrointestinal (GI)-tract microbiome and its contribution to the pathogenetic mechanisms of sporadic Alzheimer's disease (AD) came a scant 4 years ago (1). Ongoing research continues to strengthen the hypothesis that neurotoxic microbial-derived components of the GI tract microbiome can cross aging GI tract and blood-brain barriers and contribute to progressive proinflammatory neurodegeneration, as exemplified by the AD-process. Of central interest in these recent investigations are the pathological roles played by human GI tract resident Gram-negative anaerobic bacteria and neurotropic viruses-two prominent divisions of GI tract microbiome-derived microbiota-which harbor considerable pathogenic potential. It is noteworthy that the first two well-studied microbiota-the GI tract abundant Gram-negative bacteria Bacteroides fragilis and the neurotropic herpes simplex virus-1 both share a final common pathway of NF-κB (p50/p65) activation and microRNA-146a induction with ensuing pathogenic stimulation of innate-immune and neuroinflammatory pathways. These appear to strongly contribute to the inflammation-mediated amyloidogenic neuropathology of AD. This communication: (i) will review recent research contributions that have expanded our understanding of the nature of the translocation of microbiome-derived neurotoxins-across biophysiological barriers; (ii) will assess multiple-recent investigations of the induction of the proinflammatory pathogenic microRNA-146a by these two prominent classes of human microbiota; and (iii) will discuss the role of molecular neurobiology and mechanistic contribution of polymicrobial infections to AD-type neuropathological change.
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Affiliation(s)
- Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
- Department of Anatomy and Cell Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Walter J. Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
- Department of Ophthalmology, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
- Department of Neurology, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA, United States
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