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Kolahchi Z, Henkel N, Eladawi MA, Villarreal EC, Kandimalla P, Lundh A, McCullumsmith RE, Cuevas E. Sex and Gender Differences in Alzheimer's Disease: Genetic, Hormonal, and Inflammation Impacts. Int J Mol Sci 2024; 25:8485. [PMID: 39126053 PMCID: PMC11313277 DOI: 10.3390/ijms25158485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 07/26/2024] [Accepted: 07/28/2024] [Indexed: 08/12/2024] Open
Abstract
Two-thirds of Americans with Alzheimer's disease are women, indicating a profound variance between the sexes. Variances exist between the sexes in the age and intensity of the presentation, cognitive deficits, neuroinflammatory factors, structural and functional brain changes, as well as psychosocial and cultural circumstances. Herein, we summarize the existing evidence for sexual dimorphism and present the available evidence for these distinctions. Understanding these complexities is critical to developing personalized interventions for the prevention, care, and treatment of Alzheimer's disease.
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Affiliation(s)
- Zahra Kolahchi
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, School of Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA; (Z.K.); (E.C.V.)
| | - Nicholas Henkel
- Department of Neurosciences and Neurological Disorders, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA; (N.H.); (M.A.E.); (P.K.); (A.L.); (R.E.M.)
| | - Mahmoud A. Eladawi
- Department of Neurosciences and Neurological Disorders, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA; (N.H.); (M.A.E.); (P.K.); (A.L.); (R.E.M.)
| | - Emma C. Villarreal
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, School of Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA; (Z.K.); (E.C.V.)
| | - Prathik Kandimalla
- Department of Neurosciences and Neurological Disorders, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA; (N.H.); (M.A.E.); (P.K.); (A.L.); (R.E.M.)
| | - Anna Lundh
- Department of Neurosciences and Neurological Disorders, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA; (N.H.); (M.A.E.); (P.K.); (A.L.); (R.E.M.)
| | - Robert E. McCullumsmith
- Department of Neurosciences and Neurological Disorders, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA; (N.H.); (M.A.E.); (P.K.); (A.L.); (R.E.M.)
- ProMedica Neurosciences Center, Toledo, OH 43606, USA
| | - Elvis Cuevas
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, School of Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA; (Z.K.); (E.C.V.)
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Tarawneh R, Penhos E. The gut microbiome and Alzheimer's disease: Complex and bidirectional interactions. Neurosci Biobehav Rev 2022; 141:104814. [PMID: 35934087 PMCID: PMC9637435 DOI: 10.1016/j.neubiorev.2022.104814] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/16/2022] [Accepted: 08/01/2022] [Indexed: 11/20/2022]
Abstract
Structural and functional alterations to the gut microbiome, referred to as gut dysbiosis, have emerged as potential key mediators of neurodegeneration and Alzheimer disease (AD) pathogenesis through the "gut -brain" axis. Emerging data from animal and clinical studies support an important role for gut dysbiosis in mediating neuroinflammation, central and peripheral immune dysregulation, abnormal brain protein aggregation, and impaired intestinal and brain barrier permeability, leading to neuronal loss and cognitive impairment. Gut dysbiosis has also been shown to directly influence various mechanisms involved in neuronal growth and repair, synaptic plasticity, and memory and learning functions. Aging and lifestyle factors including diet, exercise, sleep, and stress influence AD risk through gut dysbiosis. Furthermore, AD is associated with characteristic gut microbial signatures which offer value as potential markers of disease severity and progression. Together, these findings suggest the presence of a complex bidirectional relationship between AD and the gut microbiome and highlight the utility of gut modulation strategies as potential preventative or therapeutic strategies in AD. We here review the current literature regarding the role of the gut-brain axis in AD pathogenesis and its potential role as a future therapeutic target in AD treatment and/or prevention.
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Affiliation(s)
- Rawan Tarawneh
- Department of Neurology, Center for Memory and Aging, Alzheimer Disease Research Center, The University of New Mexico, Albuquerque, NM 87106, USA.
| | - Elena Penhos
- College of Medicine, The Ohio State University, Columbus, OH, USA 43210
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Profile of TREM2-Derived circRNA and mRNA Variants in the Entorhinal Cortex of Alzheimer’s Disease Patients. Int J Mol Sci 2022; 23:ijms23147682. [PMID: 35887031 PMCID: PMC9320643 DOI: 10.3390/ijms23147682] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/04/2022] [Accepted: 07/04/2022] [Indexed: 02/04/2023] Open
Abstract
Genetic variants in TREM2, a microglia-related gene, are well-known risk factors for Alzheimer’s disease (AD). Here, we report that TREM2 originates from circular RNAs (circRNAs), a novel class of non-coding RNAs characterized by a covalent and stable closed-loop structure. First, divergent primers were designed to amplify circRNAs by RT-PCR, which were further assessed by Sanger sequencing. Then, additional primer sets were used to confirm back-splicing junctions. In addition, HMC3 cells were used to assess the microglial expression of circTREM2s. Three candidate circTREM2s were identified in control and AD human entorhinal samples. One of the circRNAs, circTREM2_1, was consistently amplified by all divergent primer sets in control and AD entorhinal cortex samples as well as in HMC3 cells. In AD cases, a moderate negative correlation (r = −0.434) was found between the global average area of Aβ deposits in the entorhinal cortex and circTREM2_1 expression level. In addition, by bioinformatics tools, a total of 16 miRNAs were predicted to join with circTREM2s. Finally, TREM2 mRNA corresponding to four isoforms was profiled by RT-qPCR. TREM2 mRNA levels were found elevated in entorhinal samples of AD patients with low or intermediate ABC scores compared to controls. To sum up, a novel circRNA derived from the TREM2 gene, circTREM2_1, has been identified in the human entorhinal cortex and TREM2 mRNA expression has been detected to increase in AD compared to controls. Unraveling the molecular genetics of the TREM2 gene may help to better know the innate immune response in AD.
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Lukiw WJ. NF-kB (p50/p65)-Mediated Pro-Inflammatory microRNA (miRNA) Signaling in Alzheimer's Disease (AD). Front Mol Neurosci 2022; 15:943492. [PMID: 35836546 PMCID: PMC9274251 DOI: 10.3389/fnmol.2022.943492] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Walter J. Lukiw
- LSU Neuroscience Center, Louisiana State University Health Science Center, New Orleans, LA, United States
- Department of Ophthalmology, Louisiana State University Health Science Center, New Orleans, LA, United States
- Department Neurology, Louisiana State University Health Science Center, New Orleans, LA, United States
- *Correspondence: Walter J. Lukiw
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Investigating a Curcumin-Loaded PLGA-PEG-PLGA Thermo-Sensitive Hydrogel for the Prevention of Alzheimer’s Disease. Antioxidants (Basel) 2022; 11:antiox11040727. [PMID: 35453412 PMCID: PMC9026862 DOI: 10.3390/antiox11040727] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/01/2022] [Accepted: 04/02/2022] [Indexed: 01/27/2023] Open
Abstract
In Alzheimer’s disease (AD), the most common cause of dementia, patients generally forget to take pills or skip medication due to side effects, affecting the treatment efficacy. In this study, we combined a poly(lactic-co-glycolic acid), (PLGA)-poly(ethylene glycol), and (PEG)-PLGA thermo-sensitive hydrogel with curcumin (PGC) to deliver an intramuscular injection that could continuously release curcumin and maintain it at a constant level in blood to prevent AD development or progression. We evaluated the drug release profile and cytotoxicity of PGC and its effects on AD pathology through in vitro and in vivo studies and on cognitive function through an aluminum-chloride-induced AD rat model. In the in vitro study, PGC exhibited a lack of cytotoxicity, excellent anti-inflammatory and antioxidant properties, and microglial modulation. In the Morris water maze test, the PGC injection-administered AD rats presented well-focused searching behavior with the shortest swimming path and longest retention times in the quadrant where the platform was initially located. Furthermore, PGC reduced amyloid-beta aggregation and deposition and significantly increased hippocampal activity. This study demonstrated that intramuscular PGC injection can effectively prevent AD development or progression in rats without inducing toxicity; therefore, this strategy could help overcome the present challenges in AD management in humans.
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MicroRNA-181c-5p modulates phagocytosis efficiency in bone marrow-derived macrophages. Inflamm Res 2022; 71:321-330. [PMID: 35020000 PMCID: PMC8919373 DOI: 10.1007/s00011-022-01539-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/09/2021] [Accepted: 01/03/2022] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE AND DESIGN Phagocytosis and clearance of apoptotic cells are essential for inflammation resolution, efficient wound healing, and tissue homeostasis. MicroRNAs are critical modulators of macrophage polarization and function. The current study aimed to investigate the role of miR-181c-5p in macrophage phagocytosis. MATERIALS AND METHODS miR-181c-5p was identified as a potential candidate in microRNA screening of RAW264.7 macrophages fed with apoptotic cells. To investigate the role of miR-181c-5p in phagocytosis, the expression of miR-181c-5p was assessed in phagocyting bone marrow-derived macrophages. Phagocytosis efficiency was measured by fluorescence microscopy. Gain- and loss-of-function studies were performed using miR-181c-5p-specific mimic and inhibitor. The expression of the phagocytosis-associated genes and proteins of interest was evaluated by RT2 profiler PCR array and western blotting, respectively. RESULTS miR-181c-5p expression was significantly upregulated in the phagocyting macrophages. Furthermore, mimic-induced overexpression of miR-181c-5p resulted in the increased phagocytic ability of macrophages. Moreover, overexpression of miR-181c-5p resulted in upregulation of WAVE-2 in phagocyting macrophages, suggesting that miR-181c-5p may regulate cytoskeletal arrangement during macrophage phagocytosis. CONCLUSION Altogether, our data provide a novel function of miR-181c-5p in macrophage biology and suggest that targeting macrophage miR-181c-5p in injured tissues might improve clearance of dead cells and lead to efficient inflammation resolution.
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Morris G, Puri BK, Maes M, Olive L, Berk M, Carvalho AF. The role of microglia in neuroprogressive disorders: mechanisms and possible neurotherapeutic effects of induced ketosis. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109858. [PMID: 31923453 DOI: 10.1016/j.pnpbp.2020.109858] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 12/23/2022]
Abstract
A comprehensive review of molecular mechanisms involved in the promotion and maintenance of distinct microglia phenotypes is provided. The acquisition and perpetuation of predominantly pro-inflammatory microglial phenotypes have been implicated in the pathophysiology of several neuroprogressive diseases and is associated with reduced ATP production via oxidative phosphorylation, increased ATP generation by glycolysis, elevated oxidative and nitrosative stress and other metabolic, inflammatory and hormonal insults. Microglia can also adopt a predominantly anti-inflammatory phenotypes with neuroprotective properties. Strategies that promote and maintain a predominantly anti-inflammatory phenotype may hold promise as novel therapeutic opportunities for neuroprogressive illness. Induced ketosis may promote a transition towards predominantly anti-inflammatory microglial states/phenotypes by several mechanisms, including inhibition of glycolysis and increased NAD+ production; engagement of microglial GPR109A receptors; histone deacetylase inhibition; and elevated n-3 polyunsaturated fatty acids levels. Since microglia activation can now be assessed in vivo, these data provide a clear rationale for the design of transdiagnostic randomized controlled trials of the ketogenic diet and other ketosis-inducing strategies for neuroprogressive diseases, which may also provide mechanistic insights through the assessment of "target engagement".
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | | | - Michael Maes
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Lisa Olive
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Michael Berk
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia; Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Andre F Carvalho
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada.
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Sasmita AO. Modification of the gut microbiome to combat neurodegeneration. Rev Neurosci 2019; 30:795-805. [DOI: 10.1515/revneuro-2019-0005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/16/2019] [Indexed: 12/11/2022]
Abstract
Abstract
The gut microbiome was extensively researched for its biological variety and its potential role in propagating diseases outside of the gastrointestinal (GI) tract. Recently, a lot of effort was focused on comprehending the gut-brain axis and the bizarre communication between the GI system and the nervous system. Ample amount of studies being carried out also revealed the involvement of the gut microbiome in enhancing the degree of many neurological disorders, including neurodegenerative diseases. It was widely observed that there were distinct microbiome profiles and dysbiosis within patients suffering from Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. Various approaches to re-establish the balance of the gut microbiome, from antibiotic therapy, fecal microbiota transplant, or ingestion of psychobiotics, are discussed within this review within the specific context of combating neurodegenerative diseases. Present studies and clinical trials indicate that although there is an immense potential of gut microbiome modification to be preventive or therapeutic, there are still many intercalated components of the gut-brain axis at play and thus, more research needs to be carried out to delineate microbiome factors that may potentially alleviate symptoms of neurodegeneration.
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Vasefi M, Hudson M, Ghaboolian-Zare E. Diet Associated with Inflammation and Alzheimer's Disease. J Alzheimers Dis Rep 2019; 3:299-309. [PMID: 31867568 PMCID: PMC6918878 DOI: 10.3233/adr-190152] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Neurocognitive disorders, such as Alzheimer's disease (AD), affect millions of people worldwide and are characterized by cognitive decline. Human and animal studies have shown that chronic immune response and inflammation are important factors in the pathogenesis of AD. Chronic inflammation can accelerate the aggregation of amyloid-β peptides and later hyperphosphorylation of tau proteins. The exact etiology of AD is not clear, but genetics and environmental factors, such as age, family history, and lifestyle are linked to neurodegenerative diseases. Lifestyle habits, such as poor diet, are associated with inflammation and could accelerate or slow down the progression of neurodegenerative diseases. Here we provide a review of the potential conditions and factors that stimulate the inflammatory processes in AD. An understanding of inflammatory mechanisms influencing the development of AD may help to protect against dementia and AD.
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Affiliation(s)
- Maryam Vasefi
- Department of Biology, Lamar University, Beaumont, TX, USA
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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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11
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Abstract
The gut microbiota comprises a complex community of microorganism species that resides in our gastrointestinal ecosystem and whose alterations influence not only various gut disorders but also central nervous system disorders such as Alzheimer's disease (AD). AD, the most common form of dementia, is a neurodegenerative disorder associated with impaired cognition and cerebral accumulation of amyloid-β peptides (Aβ). Most notably, the microbiota-gut-brain axis is a bidirectional communication system that is not fully understood, but includes neural, immune, endocrine, and metabolic pathways. Studies in germ-free animals and in animals exposed to pathogenic microbial infections, antibiotics, probiotics, or fecal microbiota transplantation suggest a role for the gut microbiota in host cognition or AD-related pathogenesis. The increased permeability of the gut and blood-brain barrier induced by microbiota dysbiosis may mediate or affect AD pathogenesis and other neurodegenerative disorders, especially those associated with aging. In addition, bacteria populating the gut microbiota can secrete large amounts of amyloids and lipopolysaccharides, which might contribute to the modulation of signaling pathways and the production of proinflammatory cytokines associated with the pathogenesis of AD. Moreover, imbalances in the gut microbiota can induce inflammation that is associated with the pathogenesis of obesity, type 2 diabetes mellitus, and AD. The purpose of this review is to summarize and discuss the current findings that may elucidate the role of the gut microbiota in the development of AD. Understanding the underlying mechanisms may provide new insights into novel therapeutic strategies for AD.
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Affiliation(s)
- Chunmei Jiang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Institute of Neurology, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Guangning Li
- Department of Neurology, Huadu District People's Hospital, Southern Medical University, Guangzhou, China
| | - Pengru Huang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Institute of Neurology, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Zhou Liu
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Institute of Neurology, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Bin Zhao
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Institute of Neurology, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
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Mancuso C, Santangelo R. Alzheimer's disease and gut microbiota modifications: The long way between preclinical studies and clinical evidence. Pharmacol Res 2017; 129:329-336. [PMID: 29233677 DOI: 10.1016/j.phrs.2017.12.009] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 12/15/2022]
Abstract
Recent studies have suggested the role of an infectious component in the pathogenesis of Alzheimer's disease (AD). In light of this, research has focused on some bacteria constituting the intestinal microbial flora which can produce amyloid. Once generated, the latter hypothetically triggers a systemic inflammatory response which compromises complex brain functions, such as learning and memory. Clinical studies have shown that, in cognitively impaired elderly patients with brain amyloidosis, there is lower abundance in the gut of E. rectale and B. fragilis, two bacterial species which have an anti-inflammatory activity, versus a greater amount of pro-inflammatory genera such as Escherichia/Shigella. According to these findings, some clinical studies have demonstrated that supplementation with Lactobacilli- and Bifidobacteria- based probiotics has improved cognitive, sensory and emotional functions in subjects with AD. Moreover, certain herbal products, in particular dietetic polyphenols, have proved capable of restoring dysbiosis and, therefore, their prebiotic role could be effective in counteracting the onset of AD regardless of their activity of free radical scavenging or enhancement of the cell stress response. One of the recent greatest novelties in the field of neurodegenerative diseases is the chance to prevent or slow down AD progression with agents, such as probiotics and prebiotics, acting outside the central nervous system.
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Affiliation(s)
- Cesare Mancuso
- Institute of Pharmacology, Catholic University School of Medicine, Largo F. Vito, 1-00168 Rome, Italy.
| | - Rosaria Santangelo
- Institute of Microbiology, Catholic University School of Medicine, Largo F. Vito, 1-00168 Rome, Italy
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13
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Morris G, Puri BK, Frye RE. The putative role of environmental aluminium in the development of chronic neuropathology in adults and children. How strong is the evidence and what could be the mechanisms involved? Metab Brain Dis 2017; 32:1335-1355. [PMID: 28752219 PMCID: PMC5596046 DOI: 10.1007/s11011-017-0077-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 07/19/2017] [Indexed: 02/06/2023]
Abstract
The conceptualisation of autistic spectrum disorder and Alzheimer's disease has undergone something of a paradigm shift in recent years and rather than being viewed as single illnesses with a unitary pathogenesis and pathophysiology they are increasingly considered to be heterogeneous syndromes with a complex multifactorial aetiopathogenesis, involving a highly complex and diverse combination of genetic, epigenetic and environmental factors. One such environmental factor implicated as a potential cause in both syndromes is aluminium, as an element or as part of a salt, received, for example, in oral form or as an adjuvant. Such administration has the potential to induce pathology via several routes such as provoking dysfunction and/or activation of glial cells which play an indispensable role in the regulation of central nervous system homeostasis and neurodevelopment. Other routes include the generation of oxidative stress, depletion of reduced glutathione, direct and indirect reductions in mitochondrial performance and integrity, and increasing the production of proinflammatory cytokines in both the brain and peripherally. The mechanisms whereby environmental aluminium could contribute to the development of the highly specific pattern of neuropathology seen in Alzheimer's disease are described. Also detailed are several mechanisms whereby significant quantities of aluminium introduced via immunisation could produce chronic neuropathology in genetically susceptible children. Accordingly, it is recommended that the use of aluminium salts in immunisations should be discontinued and that adults should take steps to minimise their exposure to environmental aluminium.
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Affiliation(s)
- Gerwyn Morris
- Tir Na Nog, Bryn Road seaside 87, Llanelli, Wales, SA15 2LW, UK
| | - Basant K Puri
- Department of Medicine, Imperial College London, Hammersmith Hospital, London, England, W12 0HS, UK.
| | - Richard E Frye
- College of Medicine, Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock, AR, 72202, USA
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Pistollato F, Sumalla Cano S, Elio I, Masias Vergara M, Giampieri F, Battino M. Role of gut microbiota and nutrients in amyloid formation and pathogenesis of Alzheimer disease. Nutr Rev 2016; 74:624-34. [DOI: 10.1093/nutrit/nuw023] [Citation(s) in RCA: 282] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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15
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microRNA-34a-Mediated Down-Regulation of the Microglial-Enriched Triggering Receptor and Phagocytosis-Sensor TREM2 in Age-Related Macular Degeneration. PLoS One 2016; 11:e0150211. [PMID: 26949937 PMCID: PMC4780721 DOI: 10.1371/journal.pone.0150211] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 02/10/2016] [Indexed: 12/17/2022] Open
Abstract
The aggregation of Aβ42-peptides and the formation of drusen in age-related macular degeneration (AMD) are due in part to the inability of homeostatic phagocytic mechanisms to clear self-aggregating Aβ42-peptides from the extracellular space. The triggering receptor expressed in myeloid/microglial cells-2 (TREM2), a trans-membrane-spanning, sensor-receptor of the immune-globulin/lectin-like gene superfamily is a critical component of Aβ42-peptide clearance. Here we report a significant deficit in TREM2 in AMD retina and in cytokine- or oxidatively-stressed microglial (MG) cells. RT-PCR, miRNA-array, LED-Northern and Western blot studies indicated up-regulation of a microglial-enriched NF-кB-sensitive miRNA-34a coupled to a down-regulation of TREM2 in the same samples. Bioinformatics/transfection-luciferase reporter assays indicated that miRNA-34a targets the 299 nucleotide TREM2-mRNA-3'UTR, resulting in TREM2 down-regulation. C8B4-microglial cells challenged with Aβ42 were able to phagocytose these peptides, while miRNA-34a down-regulated both TREM2 and the ability of microglial-cells to phagocytose. Treatment of TNFα-stressed MG cells with phenyl-butyl nitrone (PBN), caffeic-acid phenethyl ester (CAPE), the NF-kB - [corrected] inhibitor/resveratrol analog CAY10512 or curcumin abrogated these responses. Incubation of anti-miRNA-34a (AM-34a) normalized miRNA-34a abundance and restored TREM2 back to homeostatic levels. These data support five novel observations: (i) that a ROS- and NF-kB - [corrected] sensitive, miRNA-34a-mediated modulation of TREM2 may in part regulate the phagocytic response; (ii) that gene products encoded on two different chromosomes (miRNA-34a at chr1q36.22 and TREM2 at chr6p21.1) orchestrate a phagocytic-Aβ42-peptide clearance-system; (iii) that this NF-kB-mediated-miRNA-34a-TREM2 mechanism is inducible from outside of the cell; (iv) that when operating normally, this pathway can clear Aβ42 peptide monomers from the extracellular medium; and (v) that anti-NF-kB and/or anti-miRNA (AM)-based therapeutic strategies may be useful against deficits in TREM-2 receptor-based-sensing and -phagocytic signaling that promote pathogenic amyloidogenesis.
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MicroRNA (miRNA) Signaling in the Human CNS in Sporadic Alzheimer's Disease (AD)-Novel and Unique Pathological Features. Int J Mol Sci 2015; 16:30105-16. [PMID: 26694372 PMCID: PMC4691165 DOI: 10.3390/ijms161226223] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 12/12/2015] [Accepted: 12/15/2015] [Indexed: 02/07/2023] Open
Abstract
Of the approximately ~2.65 × 103 mature microRNAs (miRNAs) so far identified in Homo sapiens, only a surprisingly small but select subset—about 35–40—are highly abundant in the human central nervous system (CNS). This fact alone underscores the extremely high selection pressure for the human CNS to utilize only specific ribonucleotide sequences contained within these single-stranded non-coding RNAs (ncRNAs) for productive miRNA–mRNA interactions and the down-regulation of gene expression. In this article we will: (i) consolidate some of our still evolving ideas concerning the role of miRNAs in the CNS in normal aging and in health, and in sporadic Alzheimer’s disease (AD) and related forms of chronic neurodegeneration; and (ii) highlight certain aspects of the most current work in this research field, with particular emphasis on the findings from our lab of a small pathogenic family of six inducible, pro-inflammatory, NF-κB-regulated miRNAs including miRNA-7, miRNA-9, miRNA-34a, miRNA-125b, miRNA-146a and miRNA-155. This group of six CNS-abundant miRNAs significantly up-regulated in sporadic AD are emerging as what appear to be key mechanistic contributors to the sporadic AD process and can explain much of the neuropathology of this common, age-related inflammatory neurodegeneration of the human CNS.
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Zhao Y, Bhattacharjee S, Jones BM, Hill JM, Clement C, Sambamurti K, Dua P, Lukiw WJ. Beta-Amyloid Precursor Protein (βAPP) Processing in Alzheimer's Disease (AD) and Age-Related Macular Degeneration (AMD). Mol Neurobiol 2015; 52:533-44. [PMID: 25204496 PMCID: PMC4362880 DOI: 10.1007/s12035-014-8886-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 08/27/2014] [Indexed: 01/18/2023]
Abstract
Amyloid is a generic term for insoluble, often intensely hydrophobic, fibrous protein aggregates that arise from inappropriately folded versions of naturally-occurring polypeptides. The abnormal generation and accumulation of amyloid, often referred to as amyloidogenesis, has been associated with the immune and pro-inflammatory pathology of several progressive age-related diseases of the human central nervous system (CNS) including Alzheimer's disease (AD) and age-related macular degeneration (AMD). This 'research perspective' paper reviews some of the research history, biophysics, molecular-genetics and environmental factors concerning the contribution of amyloid beta (Aβ) peptides, derived from beta-amyloid precursor protein (βAPP), to AD and AMD that suggests an extensive similarity in immune and inflammatory degenerative mechanisms between these two CNS diseases.
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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
| | - Surjyadipta Bhattacharjee
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
| | - Brandon M. Jones
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
| | - James M. Hill
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
- Department of Ophthalmology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
- Department of Microbiology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
- Department of Pharmacology, 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
| | - Christian Clement
- Department of Natural Sciences, Infectious Diseases, Experimental Therapeutics and Human Toxicology Lab, Southern University at New Orleans, New Orleans, LA 70126 USA
| | | | - Prerna Dua
- Department of Health Information Management, Louisiana State University, Ruston, LA 71272 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 Ophthalmology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
- Department of Microbiology, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite 904, New Orleans LA 70112 USA
- Department of Natural Sciences, Infectious Diseases, Experimental Therapeutics and Human Toxicology Lab, Southern University at New Orleans, New Orleans, LA 70126 USA
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Zhao Y, Lukiw WJ. Microbiome-generated amyloid and potential impact on amyloidogenesis in Alzheimer's disease (AD). JOURNAL OF NATURE AND SCIENCE 2015; 1:e138. [PMID: 26097896 PMCID: PMC4469284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
According to the 'amyloid cascade hypothesis of Alzheimer's disease' first proposed about 16 years ago, the accumulation of Aβ peptides in the human central nervous system (CNS) is the primary influence driving Alzheimer's disease (AD) pathogenesis, and Aβ peptide accretion is the result of an imbalance between Aβ peptide production and clearance. In the last 18 months multiple laboratories have reported two particularly important observations: (i) that because the microbes of the human microbiome naturally secrete large amounts of amyloid, lipopolysaccharides (LPS) and other related pro-inflammatory pathogenic signals, these may contribute to both the systemic and CNS amyloid burden in aging humans; and (ii) that the clearance of Aβ peptides appears to be intrinsically impaired by deficits in the microglial plasma-membrane enriched triggering receptor expressed in microglial/myeloid-2 cells (TREM2). This brief general commentary-perspective paper: (i) will highlight some of these very recent findings on microbiome-secreted amyloids and LPS and the potential contribution of these microbial-derived pro-inflammatory and neurotoxic exudates to age-related inflammatory and AD-type neurodegeneration in the host; and (ii) will discuss the contribution of a defective microglial-based TREM2 transmembrane sensor-receptor system to amyloidogenesis in AD that is in contrast to the normal, homeostatic clearance of Aβ peptides from the human CNS.
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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 Ophthalmology, 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
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Latypova X, Martin L. 2015: which new directions for Alzheimer's disease? Front Cell Neurosci 2014; 8:417. [PMID: 25538567 PMCID: PMC4260501 DOI: 10.3389/fncel.2014.00417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 11/17/2014] [Indexed: 01/06/2023] Open
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20
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Zhao Y, Hill JM, Bhattacharjee S, Percy ME, Pogue AID, Lukiw WJ. Aluminum-induced amyloidogenesis and impairment in the clearance of amyloid peptides from the central nervous system in Alzheimer's disease. Front Neurol 2014; 5:167. [PMID: 25250012 PMCID: PMC4155793 DOI: 10.3389/fneur.2014.00167] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 08/20/2014] [Indexed: 12/03/2022] Open
Affiliation(s)
- Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA ; Department of Ophthalmology, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA
| | - James M Hill
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA ; Department of Ophthalmology, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA ; Department of Microbiology, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA
| | - Surjyadipta Bhattacharjee
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA
| | - Maire E Percy
- Department of Physiology, University of Toronto , Toronto, ON , Canada ; Department of Obstetrics and Gynaecology, University of Toronto , Toronto, ON , Canada ; Neurogenetics Laboratory, Surrey Place Centre , Toronto, ON , Canada
| | | | - Walter J Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA ; Department of Ophthalmology, Louisiana State University Health Sciences Center, Louisiana State University , New Orleans, LA , USA ; Alchem Biotech , Toronto, ON , Canada ; Department of Neurology, Louisiana State University Health Sciences Center , New Orleans, LA , USA
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21
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Bhattacharjee S, Zhao Y, Lukiw WJ. Deficits in the miRNA-34a-regulated endogenous TREM2 phagocytosis sensor-receptor in Alzheimer's disease (AD); an update. Front Aging Neurosci 2014; 6:116. [PMID: 24987367 PMCID: PMC4060025 DOI: 10.3389/fnagi.2014.00116] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 05/24/2014] [Indexed: 01/22/2023] Open
Affiliation(s)
- Surjyadipta Bhattacharjee
- Departments of Neurology, Neuroscience and Ophthalmology, Louisiana State University Neuroscience Center and Health Sciences Center New Orleans, LA, USA
| | - Yuhai Zhao
- Departments of Neurology, Neuroscience and Ophthalmology, Louisiana State University Neuroscience Center and Health Sciences Center New Orleans, LA, USA
| | - Walter J Lukiw
- Departments of Neurology, Neuroscience and Ophthalmology, Louisiana State University Neuroscience Center and Health Sciences Center New Orleans, LA, USA
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22
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Hill JM, Bhattacharjee S, Pogue AI, Lukiw WJ. The gastrointestinal tract microbiome and potential link to Alzheimer's disease. Front Neurol 2014; 5:43. [PMID: 24772103 PMCID: PMC3983497 DOI: 10.3389/fneur.2014.00043] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 03/21/2014] [Indexed: 12/26/2022] Open
Affiliation(s)
- James M Hill
- LSU Neuroscience Center, Louisiana State University Health Sciences Center , New Orleans, LA , USA ; Department of Microbiology, Louisiana State University Health Sciences Center , New Orleans, LA , USA ; Department of Ophthalmology, Louisiana State University Health Sciences Center , New Orleans, LA , USA
| | | | | | - Walter J Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center , New Orleans, LA , USA ; Department of Ophthalmology, Louisiana State University Health Sciences Center , New Orleans, LA , USA ; Alchem Biotek , Toronto, ON , Canada ; Department of Neurology, Louisiana State University Health Sciences Center , New Orleans, LA , USA
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23
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Jones BM, Bhattacharjee S, Dua P, Hill JM, Zhao Y, Lukiw WJ. Regulating amyloidogenesis through the natural triggering receptor expressed in myeloid/microglial cells 2 (TREM2). Front Cell Neurosci 2014; 8:94. [PMID: 24744699 PMCID: PMC3978349 DOI: 10.3389/fncel.2014.00094] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/13/2014] [Indexed: 11/23/2022] Open
Affiliation(s)
- Brandon M Jones
- LSU Neuroscience Center, Louisiana State University Health Sciences Center (LSUHSC) New Orleans, LA, USA
| | - Surjyadipta Bhattacharjee
- LSU Neuroscience Center, Louisiana State University Health Sciences Center (LSUHSC) New Orleans, LA, USA
| | - Prerna Dua
- Department of Health Information Management, Louisiana State University Ruston, LA, USA
| | - James M Hill
- LSU Neuroscience Center, Louisiana State University Health Sciences Center (LSUHSC) New Orleans, LA, USA ; Department of Ophthalmology, Health Sciences Center, Louisiana State University New Orleans, LA, USA
| | - Yuhai Zhao
- Department of Ophthalmology, Health Sciences Center, Louisiana State University New Orleans, LA, USA
| | - Walter J Lukiw
- LSU Neuroscience Center, Louisiana State University Health Sciences Center (LSUHSC) New Orleans, LA, USA ; Department of Ophthalmology, Health Sciences Center, Louisiana State University New Orleans, LA, USA ; Department of Neurology, Health Sciences Center, Louisiana State University New Orleans, LA, USA
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