201
|
Rai SK, Savastano A, Singh P, Mukhopadhyay S, Zweckstetter M. Liquid-liquid phase separation of tau: From molecular biophysics to physiology and disease. Protein Sci 2021; 30:1294-1314. [PMID: 33930220 PMCID: PMC8197432 DOI: 10.1002/pro.4093] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022]
Abstract
Biomolecular condensation via liquid-liquid phase separation (LLPS) of intrinsically disordered proteins/regions (IDPs/IDRs), with and without nucleic acids, has drawn widespread interest due to the rapidly unfolding role of phase-separated condensates in a diverse range of cellular functions and human diseases. Biomolecular condensates form via transient and multivalent intermolecular forces that sequester proteins and nucleic acids into liquid-like membrane-less compartments. However, aberrant phase transitions into gel-like or solid-like aggregates might play an important role in neurodegenerative and other diseases. Tau, a microtubule-associated neuronal IDP, is involved in microtubule stabilization, regulates axonal outgrowth and transport in neurons. A growing body of evidence indicates that tau can accomplish some of its cellular activities via LLPS. However, liquid-to-solid transition resulting in the abnormal aggregation of tau is associated with neurodegenerative diseases. The physical chemistry of tau is crucial for governing its propensity for biomolecular condensation which is governed by various intermolecular and intramolecular interactions leading to simple one-component and complex multi-component condensates. In this review, we aim at capturing the current scientific state in unveiling the intriguing molecular mechanism of phase separation of tau. We particularly focus on the amalgamation of existing and emerging biophysical tools that offer unique spatiotemporal resolutions on a wide range of length- and time-scales. We also discuss the link between quantitative biophysical measurements and novel biological insights into biomolecular condensation of tau. We believe that this account will provide a broad and multidisciplinary view of phase separation of tau and its association with physiology and disease.
Collapse
Affiliation(s)
- Sandeep K. Rai
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)MohaliIndia
| | - Adriana Savastano
- Research group Translational Structural BiologyGerman Center for Neurodegenerative Diseases (DZNE)GöttingenGermany
| | - Priyanka Singh
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)MohaliIndia
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)MohaliIndia
| | - Markus Zweckstetter
- Research group Translational Structural BiologyGerman Center for Neurodegenerative Diseases (DZNE)GöttingenGermany
- Department for NMR‐based Structural BiologyMax Planck Institute for Biophysical ChemistryGöttingenGermany
| |
Collapse
|
202
|
Abstract
Alzheimer's disease (AD) is an irreversible brain disorder associated with severe progressive dementia and is characterized by deposits of amyloid plaques in the brain. Over the past 20 years, the mortality of strokes and heart disease has decreased, but deaths from AD have increased. The four drugs used clinically to treat AD can only relieve symptoms but cannot slow the progression of the disease. Aducanumab, a human monoclonal antibody that preferentially binds to aggregated amyloid-β to reduce the number of amyloid plaques and slow disease progression, was approved to treat AD by the US Food and Drug Administration on June 7, 2021. It is the first disease-modifying therapy for AD, but there is considerable controversy regarding the drug's approval. Aducanumab offers hope for millions of patients.
Collapse
Affiliation(s)
- Pan Yang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, Shandong, China
| | - Fusheng Sun
- Department of Pharmacy, Qingdao Municipal Hospital, Qingdao, Shandong, China
| |
Collapse
|
203
|
Caesalpinia sappan L. Ameliorates Scopolamine-Induced Memory Deficits in Mice via the cAMP/PKA/CREB/BDNF Pathway. Sci Pharm 2021. [DOI: 10.3390/scipharm89020029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Memory is an essential aspect of human cognition. A decrease in this aspect is well associated with Alzheimer’s disease (AD). The development of a novel cognitive enhancer (CE) may help overcome AD-related problems. In this study, we evaluated the CE effect of Caesalpinia sappan L. (CS) in memory deficit mice. Administration of its ethanolic extract (250 and 500 mg/kg body weight (BW)) and brazilin (5 and 10 mg/kg BW) ameliorated the scopolamine-amnesic effect, as evidenced by significant decreases (p < 0.01, p < 0.05) in the escape latency time and increases (p < 0.01) in the percentage of time spent in the target quadrant of the Morris water maze test. We also examined the cyclic adenosine monophosphate (cAMP) level, protein kinase A (PKA) activity, and protein expression levels of phosphorylated cAMP response element binding (pCREB) and brain-derived neurotrophic factor (BDNF) in hippocampal tissues to elucidate the underlying molecular mechanism. Results showed that CS wood ethanolic extract and brazilin not only significantly increase (p < 0.01, p < 0.05) cAMP levels and PKA activity but also significantly enhance (p < 0.01, p < 0.05) the expression level of pCREB and BDNF in the hippocampus. These findings indicate that CS activates the cAMP/PKA/CREB/BDNF pathway. Taken together, our results demonstrate that CS is a promising herb that could be developed as a CE agent.
Collapse
|
204
|
Wang C, Gao WR, Yin J, Wang ZJ, Qi JS, Cai HY, Wu MN. Chronic sleep deprivation exacerbates cognitive and synaptic plasticity impairments in APP/PS1 transgenic mice. Behav Brain Res 2021; 412:113400. [PMID: 34087256 DOI: 10.1016/j.bbr.2021.113400] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/27/2021] [Accepted: 05/30/2021] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive deficits. Sleep deprivation (SD) could lead to memory deficits, and it was a candidate risk factor for AD. However, the effects of chronic SD on the cognitive functions of AD model mice and its possible mechanism are still unclear. In the present study, 8-month-old male APP/PS1 transgenic mice and wild type (WT) littermates were subjected to chronic SD by using the modified multiple platform method (MMPM), with 20 h of SD each day for 21 days. Then, the effects of chronic SD on cognitive functions in APP/PS1 mice were tested by using behavioral tests, the potential mechanisms were investigated by in vivo electrophysiological recording, western blot and immunochemistry. The results showed that chronic SD obviously aggravated the cognitive impairments, exacerbated in vivo hippocampal long-term potentiation (LTP) suppression, reduced the expression level of PSD95, increased amyloid-β (Aβ) protein deposition and overactivated microglia in the hippocampus of APP/PS1 mice. These results indicate that chronic SD exacerbates the cognitive deficits in APP/PS1 mice by accelerating the development of AD pathologies, reducing the expression of PSD95 and aggravating the LTP suppression in hippocampus. At the same time, chronic SD also impaired cognitive functions and synaptic plasticity in WT mice through down-regulating the level of PSD95 and activating microglia. These findings further clarify the electrophysiological and molecular mechanisms of exacerbated cognitive deficits in AD caused by chronic SD.
Collapse
Affiliation(s)
- Chun Wang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China
| | - Wen-Rui Gao
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China
| | - Jing Yin
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China
| | - Zhao-Jun Wang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China
| | - Jin-Shun Qi
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China
| | - Hong-Yan Cai
- Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan, 030001, China.
| | - Mei-Na Wu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China.
| |
Collapse
|
205
|
Daoutsali E, Hailu TT, Buijsen RAM, Pepers BA, van der Graaf LM, Verbeek MM, Curtis D, de Vlaam T, van Roon-Mom WMC. Antisense Oligonucleotide-Induced Amyloid Precursor Protein Splicing Modulation as a Therapeutic Approach for Dutch-Type Cerebral Amyloid Angiopathy. Nucleic Acid Ther 2021; 31:351-363. [PMID: 34061681 PMCID: PMC8823675 DOI: 10.1089/nat.2021.0005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Dutch-type cerebral amyloid angiopathy (D-CAA) is a monogenic form of cerebral amyloid angiopathy and is inherited in an autosomal dominant manner. The disease is caused by a point mutation in exon 17 of the amyloid precursor protein (APP) gene that leads to an amino acid substitution at codon 693. The mutation is located within the amyloid beta (Aβ) domain of APP, and leads to accumulation of toxic Aβ peptide in and around the cerebral vasculature. We have designed an antisense oligonucleotide (AON) approach that results in skipping of exon 17, generating a shorter APP isoform that lacks part of the Aβ domain and the D-CAA mutation. We demonstrate efficient AON-induced skipping of exon 17 at RNA level and the occurrence of a shorter APP protein isoform in three different cell types. This resulted in a reduction of Aβ40 in neuronally differentiated, patient-derived induced pluripotent stem cells. AON-treated wild-type mice showed successful exon skipping on RNA and protein levels throughout the brain. These results illustrate APP splice modulation as a promising therapeutic approach for D-CAA.
Collapse
Affiliation(s)
- Elena Daoutsali
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | | | - Ronald A M Buijsen
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Barry A Pepers
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Linda M van der Graaf
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Marcel M Verbeek
- Departments of Neurology and Laboratory Medicine, Radboud Alzheimer Centre, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | - Daniel Curtis
- Amylon Therapeutics, Leiden, the Netherlands.,Atalanta Therapeutics, Boston, Massachusetts, USA
| | | | | |
Collapse
|
206
|
Targeting the Transnitrosylation Cascade Provides a Novel Therapeutic Strategy for Alzheimer's Disease. Neurosci Bull 2021; 37:1373-1376. [PMID: 34041711 DOI: 10.1007/s12264-021-00710-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/02/2021] [Indexed: 10/21/2022] Open
|
207
|
Chen X, Drew J, Berney W, Lei W. Neuroprotective Natural Products for Alzheimer's Disease. Cells 2021; 10:1309. [PMID: 34070275 PMCID: PMC8225186 DOI: 10.3390/cells10061309] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/17/2021] [Accepted: 05/22/2021] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is the number one neurovegetative disease, but its treatment options are relatively few and ineffective. In efforts to discover new strategies for AD therapy, natural products have aroused interest in the research community and in the pharmaceutical industry for their neuroprotective activity, targeting different pathological mechanisms associated with AD. A wide variety of natural products from different origins have been evaluated preclinically and clinically for their neuroprotective mechanisms in preventing and attenuating the multifactorial pathologies of AD. This review mainly focuses on the possible neuroprotective mechanisms from natural products that may be beneficial in AD treatment and the natural product mixtures or extracts from different sources that have demonstrated neuroprotective activity in preclinical and/or clinical studies. It is believed that natural product mixtures or extracts containing multiple bioactive compounds that can work additively or synergistically to exhibit multiple neuroprotective mechanisms might be an effective approach in AD drug discovery.
Collapse
Affiliation(s)
- Xin Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC 27506, USA
| | - Joshua Drew
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC 27506, USA
| | - Wren Berney
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC 27506, USA
| | - Wei Lei
- Department of Pharmaceutical and Administrative Sciences, School of Pharmacy, Presbyterian College, Clinton, SC 29325, USA
| |
Collapse
|
208
|
Ouyang Q, Meng Y, Zhou W, Tong J, Cheng Z, Zhu Q. New advances in brain-targeting nano-drug delivery systems for Alzheimer's disease. J Drug Target 2021; 30:61-81. [PMID: 33983096 DOI: 10.1080/1061186x.2021.1927055] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide and its incidence is increasing due to the ageing population. Currently, the main limitations of AD treatment are low blood-brain barrier permeability, severe off-target of drugs, and immune abnormality. In this review, four hypotheses for Alzheimer's pathogenesis and three challenges for Alzheimer's drug delivery are discussed. In addition, this article summarises the different strategies of brain targeting nano-drug delivery systems (NDDSs) developed in the last 10 years. These strategies include receptor-mediated (transferrin receptor, low-density lipoprotein receptor-related protein, lactoferrin receptor, etc.), adsorption-mediated (cationic, alkaline polypeptide, cell-penetrating peptides, etc.), and transporter-mediated (P-gp, GLUT1, etc.). Moreover, it provides insights into novel strategies used in AD, such as exosomes, virus-like particles, and cell membrane coating particles. Hence, this review will help researchers to understand the current progress in the field of NDDSs for the central nervous system and find new directions for AD therapy.HighlightsCharacteristics and challenges based on the pathogenesis of AD were discussed.Recent advances in novel brain-targeting NDDSs for AD over the past 10 years were summarised.
Collapse
Affiliation(s)
- Qin Ouyang
- Xiangya School of Pharmaceutical Sciences in Central South University, Changsha, Hunan, China
| | - Yingcai Meng
- Xiangya School of Pharmaceutical Sciences in Central South University, Changsha, Hunan, China
| | - Wenhu Zhou
- Xiangya School of Pharmaceutical Sciences in Central South University, Changsha, Hunan, China
| | - Jianbin Tong
- Department of Anaesthesiology, Third Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China.,Hunan Province Key Laboratory of Brain Homeostasis, Third Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Zeneng Cheng
- Xiangya School of Pharmaceutical Sciences in Central South University, Changsha, Hunan, China
| | - Qubo Zhu
- Xiangya School of Pharmaceutical Sciences in Central South University, Changsha, Hunan, China
| |
Collapse
|
209
|
Alves SS, Silva-Junior RMPD, Servilha-Menezes G, Homolak J, Šalković-Petrišić M, Garcia-Cairasco N. Insulin Resistance as a Common Link Between Current Alzheimer's Disease Hypotheses. J Alzheimers Dis 2021; 82:71-105. [PMID: 34024838 DOI: 10.3233/jad-210234] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Almost 115 years ago, Alois Alzheimer described Alzheimer's disease (AD) for the first time. Since then, many hypotheses have been proposed. However, AD remains a severe health public problem. The current medical approaches for AD are limited to symptomatic interventions and the complexity of this disease has led to a failure rate of approximately 99.6%in AD clinical trials. In fact, no new drug has been approved for AD treatment since 2003. These failures indicate that we are failing in mimicking this disease in experimental models. Although most studies have focused on the amyloid cascade hypothesis of AD, the literature has made clear that AD is rather a multifactorial disorder. Therefore, the persistence in a single theory has resulted in lost opportunities. In this review, we aim to present the striking points of the long scientific path followed since the description of the first AD case and the main AD hypotheses discussed over the last decades. We also propose insulin resistance as a common link between many other hypotheses.
Collapse
Affiliation(s)
- Suélen Santos Alves
- Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School - University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| | - Rui Milton Patrício da Silva-Junior
- Department of Internal Medicine, Ribeirão Preto Medical School -University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil.,Department of Physiology, Ribeirão Preto Medical School - University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| | - Gabriel Servilha-Menezes
- Department of Physiology, Ribeirão Preto Medical School - University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| | - Jan Homolak
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Melita Šalković-Petrišić
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Norberto Garcia-Cairasco
- Department of Neurosciences and Behavioral Sciences, Ribeirão Preto Medical School - University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil.,Department of Physiology, Ribeirão Preto Medical School - University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil
| |
Collapse
|
210
|
Knopman DS, Amieva H, Petersen RC, Chételat G, Holtzman DM, Hyman BT, Nixon RA, Jones DT. Alzheimer disease. Nat Rev Dis Primers 2021; 7:33. [PMID: 33986301 PMCID: PMC8574196 DOI: 10.1038/s41572-021-00269-y] [Citation(s) in RCA: 890] [Impact Index Per Article: 296.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/09/2021] [Indexed: 12/21/2022]
Abstract
Alzheimer disease (AD) is biologically defined by the presence of β-amyloid-containing plaques and tau-containing neurofibrillary tangles. AD is a genetic and sporadic neurodegenerative disease that causes an amnestic cognitive impairment in its prototypical presentation and non-amnestic cognitive impairment in its less common variants. AD is a common cause of cognitive impairment acquired in midlife and late-life but its clinical impact is modified by other neurodegenerative and cerebrovascular conditions. This Primer conceives of AD biology as the brain disorder that results from a complex interplay of loss of synaptic homeostasis and dysfunction in the highly interrelated endosomal/lysosomal clearance pathways in which the precursors, aggregated species and post-translationally modified products of Aβ and tau play important roles. Therapeutic endeavours are still struggling to find targets within this framework that substantially change the clinical course in persons with AD.
Collapse
Affiliation(s)
| | - Helene Amieva
- Inserm U1219 Bordeaux Population Health Center, University of Bordeaux, Bordeaux, France
| | | | - Gäel Chételat
- Normandie Univ, UNICAEN, INSERM, U1237, PhIND "Physiopathology and Imaging of Neurological Disorders", Institut Blood and Brain @ Caen-Normandie, Cyceron, Caen, France
| | - David M Holtzman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bradley T Hyman
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Ralph A Nixon
- Departments of Psychiatry and Cell Biology, New York University Langone Medical Center, New York University, New York, NY, USA
- NYU Neuroscience Institute, New York University Langone Medical Center, New York University, New York, NY, USA
| | - David T Jones
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| |
Collapse
|
211
|
The Protective A673T Mutation of Amyloid Precursor Protein (APP) in Alzheimer's Disease. Mol Neurobiol 2021; 58:4038-4050. [PMID: 33914267 DOI: 10.1007/s12035-021-02385-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/05/2021] [Indexed: 10/21/2022]
Abstract
Alzheimer's disease is a progressive neurodegenerative disorder characterized by extracellular amyloid beta peptides and neurofibrillary tangles consisted of intracellular hyperphosphorylated Tau in the hippocampus and cerebral cortex. Most of the mutations in key genes that code for amyloid precursor protein can lead to significant accumulation of these peptides in the brain and cause Alzheimer's disease. Moreover, some point mutations in amyloid precursor protein can cause familial Alzheimer's disease, such as Swedish mutation (KM670/671NL) and A673V mutation. However, recent studies have found that the A673T mutation in amyloid precursor protein gene can protect against Alzheimer's disease, even if it is located next to the Swedish mutation (KM670/671NL) and at the same site as A673V mutation, which are pathogenic. It makes us curious about the protective A673T mutation. Here, we summarize the most recent insights of A673T mutation, focus on their roles in protective mechanisms against Alzheimer's disease, and discuss their involvement in future treatment.
Collapse
|
212
|
Bachstetter AD, Garrett FG, Jicha GA, Nelson PT. Space-occupying brain lesions, trauma-related tau astrogliopathy, and ARTAG: a report of two cases and a literature review. Acta Neuropathol Commun 2021; 9:49. [PMID: 33757579 PMCID: PMC7986305 DOI: 10.1186/s40478-021-01152-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 12/14/2022] Open
Abstract
Astrocytes with intracellular accumulations of misfolded phosphorylated tau protein have been observed in advanced-stage chronic traumatic encephalopathy (CTE) and in other neurodegenerative conditions. There is a growing awareness that astrocytic tau inclusions are also relatively common in the brains of persons over 70 years of age-affecting approximately one-third of autopsied individuals. The pathologic hallmarks of aging-related tau astrogliopathy (ARTAG) include phosphorylated tau protein within thorn-shaped astrocytes (TSA) in subpial, subependymal, perivascular, and white matter regions, whereas granular-fuzzy astrocytes are often seen in gray matter. CTE and ARTAG share molecular and histopathologic characteristics, suggesting that trauma-related mechanism(s) may predispose to the development of tau astrogliopathy. There are presently few experimental systems to study the pathobiology of astrocytic-tau aggregation, but human studies have made recent progress. For example, leucotomy (also referred to as lobotomy) is associated with a localized ARTAG-like neuropathology decades after the surgical brain injury, suggesting that chronic brain injury of any type may predispose to later life ARTAG. To examine this idea in a different context, we report clinical and pathologic features of two middle-aged men who came to autopsy with large (> 6 cm in greatest dimension) arachnoid cysts that had physically displaced and injured the subjects' left temporal lobes through chronic mechanical stress. Despite the similarity of the size and location of the arachnoid cysts, these individuals had dissimilar neurologic outcomes and neuropathologic findings. We review the evidence for ARTAG in response to brain injury, and discuss how the location and molecular properties of astroglial tau inclusions might alter the physiology of resident astrocytes. These cases and literature review point toward possible mechanism(s) of tau aggregation in astrocytes in response to chronic brain trauma.
Collapse
Affiliation(s)
- Adam D Bachstetter
- Spinal Cord and Brain Injury Research Center, University of Kentucky, 741 S. Limestone St., Lexington, KY, 40536, USA.
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA.
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
| | - Filip G Garrett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA
| | - Gregory A Jicha
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - Peter T Nelson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA
| |
Collapse
|
213
|
Imbimbo BP, Ippati S, Watling M, Balducci C. Accelerating Alzheimer's disease drug discovery and development: what's the way forward? Expert Opin Drug Discov 2021; 16:727-735. [PMID: 33653187 DOI: 10.1080/17460441.2021.1887132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: As the global burden of Alzheimer's disease (AD) grows, an effective disease-modifying therapy remains a distant prospect following the repeated failure of multiple therapeutics targeting β-amyloid and (it seems) tau over many years of costly effort. The repeated failure of single-target therapies to meaningfully modify disease progression raises major questions about the validity of many aspects of drug development in this area, especially target selection.Area covered: The authors explore the critical questions raised by a review of the collective experience to date, relating to why findings with non-clinical models and clinical biomarkers so frequently fail to translate to positive outcomes in clinical trials, which alternatives should be considered, and how we can design and conduct clinical trials that can successfully identify and quantify meaningful benefits in the future.Expert opinion: It is our opinion that we must recognize and accept the need to consider less specific, more multimodal approaches to addressing neurodegeneration in AD if we are to make progress - and we must avoid repeating the well intentioned, but ultimately erroneous, assumptions of the past.
Collapse
Affiliation(s)
- Bruno P Imbimbo
- Department of Research & Development, Chiesi Farmaceutici, Parma, Italy
| | - Stefania Ippati
- Experimental Imaging Center, San Raffaele Scientific Institute, Milan, Italy
| | - Mark Watling
- CNS & Pain Department, TranScrip Partners, Reading, UK
| | - Claudia Balducci
- Department of Neuroscience, IRCCS, Istituto Di Ricerche Farmacologiche "Mario Negri", Milan, Italy
| |
Collapse
|
214
|
Is γ-secretase a beneficial inactivating enzyme of the toxic APP C-terminal fragment C99? J Biol Chem 2021; 296:100489. [PMID: 33662398 PMCID: PMC8027268 DOI: 10.1016/j.jbc.2021.100489] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 12/12/2022] Open
Abstract
Genetic, biochemical, and anatomical grounds led to the proposal of the amyloid cascade hypothesis centered on the accumulation of amyloid beta peptides (Aβ) to explain Alzheimer's disease (AD) etiology. In this context, a bulk of efforts have aimed at developing therapeutic strategies seeking to reduce Aβ levels, either by blocking its production (γ- and β-secretase inhibitors) or by neutralizing it once formed (Aβ-directed immunotherapies). However, so far the vast majority of, if not all, clinical trials based on these strategies have failed, since they have not been able to restore cognitive function in AD patients, and even in many cases, they have worsened the clinical picture. We here propose that AD could be more complex than a simple Aβ-linked pathology and discuss the possibility that a way to reconcile undoubted genetic evidences linking processing of APP to AD and a consistent failure of Aβ-based clinical trials could be to envision the pathological contribution of the direct precursor of Aβ, the β-secretase-derived C-terminal fragment of APP, βCTF, also referred to as C99. In this review, we summarize scientific evidences pointing to C99 as an early contributor to AD and postulate that γ-secretase should be considered as not only an Aβ-generating protease, but also a beneficial C99-inactivating enzyme. In that sense, we discuss the limitations of molecules targeting γ-secretase and propose alternative strategies seeking to reduce C99 levels by other means and notably by enhancing its lysosomal degradation.
Collapse
|
215
|
Zetterberg H, Blennow K. Moving fluid biomarkers for Alzheimer's disease from research tools to routine clinical diagnostics. Mol Neurodegener 2021; 16:10. [PMID: 33608044 PMCID: PMC7893769 DOI: 10.1186/s13024-021-00430-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 02/05/2021] [Indexed: 12/31/2022] Open
Abstract
Four fluid-based biomarkers have been developed into diagnostic tests for Alzheimer’s disease (AD) pathology: the ratio of 42 to 40 amino acid-long amyloid β, a marker of plaque pathology; total-tau and phosphorylated tau, markers of AD-related changes in tau metabolism and secretion; and neurofilament light, a marker of neurodegeneration. When measured in cerebrospinal fluid, these biomarkers can be used in clinical practice to support a diagnosis of mild cognitive impairment or dementia due to AD. Recently, technological breakthroughs have made it possible to measure them in standard blood samples as well. Here, we give an updated account of the current state of the fluid-based AD biomarker research field. We discuss how the new blood tests may be used in research and clinical practice, and what role they may play in relation to more established diagnostic tests, such as CSF biomarkers and amyloid and tau positron emission tomography, to facilitate the effective implementation of future disease-modifying therapies.
Collapse
Affiliation(s)
- Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden. .,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden. .,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK. .,UK Dementia Research Institute at UCL, London, UK.
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden. .,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.
| |
Collapse
|
216
|
Si Z, Wang X. Stem Cell Therapies in Alzheimer's Disease: Applications for Disease Modeling. J Pharmacol Exp Ther 2021; 377:207-217. [PMID: 33558427 DOI: 10.1124/jpet.120.000324] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 02/03/2021] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease with complex pathologic and biologic characteristics. Extracellular β-amyloid deposits, such as senile plaques, and intracellular aggregation of hyperphosphorylated tau, such as neurofibrillary tangles, remain the main neuropathological criteria for the diagnosis of AD. There is currently no effective treatment of the disease, and many clinical trials have failed to prove any benefits of new therapeutics. More recently, there has been increasing interest in harnessing the potential of stem cell technologies for drug discovery, disease modeling, and cell therapies, which have been used to study an array of human conditions, including AD. The recently developed and optimized induced pluripotent stem cell (iPSC) technology is a critical platform for screening anti-AD drugs and understanding mutations that modify AD. Neural stem cell (NSC) transplantation has been investigated as a new therapeutic approach to treat neurodegenerative diseases. Mesenchymal stem cells (MSCs) also exhibit considerable potential to treat neurodegenerative diseases by secreting growth factors and exosomes, attenuating neuroinflammation. This review highlights recent progress in stem cell research and the translational applications and challenges of iPSCs, NSCs, and MSCs as treatment strategies for AD. Even though these treatments are still in relative infancy, these developing stem cell technologies hold considerable promise to combat AD and other neurodegenerative disorders. SIGNIFICANCE STATEMENT: Alzheimer's disease (AD) is a neurodegenerative disease that results in learning and memory defects. Although some drugs have been approved for AD treatment, fewer than 20% of patients with AD benefit from these drugs. Therapies based on stem cells, including induced pluripotent stem cells, neural stem cells, and mesenchymal stem cells, provide promising therapeutic strategies for AD.
Collapse
Affiliation(s)
- Zizhen Si
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, Ningbo, China (Z.S.) and Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, China (X.W.)
| | - Xidi Wang
- Department of Physiology and Pharmacology, School of Medicine, Ningbo University, Ningbo, China (Z.S.) and Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, China (X.W.)
| |
Collapse
|
217
|
Ahmed TF, Ahmed A, Imtiaz F. History in perspective: How Alzheimer's Disease came to be where it is? Brain Res 2021; 1758:147342. [PMID: 33548268 DOI: 10.1016/j.brainres.2021.147342] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/18/2021] [Accepted: 01/28/2021] [Indexed: 01/03/2023]
Abstract
Treatment of Alzheimer's Disease (AD) remains an unsolved issue despite the pronounced global attention it has received from researchers over the last four decades. Determining the primary cause of the disease is challenging due to its long prodromal phase and multifactorial etiology. Regardless, academic disagreements amongst the scientific community have helped in making significant advancements in underpinning the molecular basis of disease pathogenesis. Substantial development in fluid and imaging biomarkers for AD led to a sharp turn in defining the disease as a molecular construct, dispensing its clinical definition. With conceptual progress, revisions in the diagnostic criteria of AD were made, culminating into the research framework proposed by National Institute on Aging and Alzheimer's Association in 2018 which unified different stages of the disease continuum, giving a common language of AT(N)1 classification to researchers. With realization that dementia is the final stage of AD spectrum, its early diagnosis by means of cerebrospinal fluid biomarkers, Positron Emission Tomography and Magnetic Resonance Imaging of the brain holds crucial importance in discovering ways of halting the disease progression. This article maps the insights into the pathogenesis as well as the diagnostic criteria and tests for AD as these have evolved over time. A contextualized timeline of how the understanding of AD has matured with advancing knowledge allows future research to be directed and unexplored avenues to be prioritized.
Collapse
Affiliation(s)
- Tehniat F Ahmed
- Department of Biochemistry, Institute of Biomedical Sciences, Dow University of Health Sciences, Karachi, Pakistan.
| | - Affan Ahmed
- Dow Medical College, Dow University of Health Sciences, Karachi, Pakistan
| | - Fauzia Imtiaz
- Department of Biochemistry, Dow Medical College, Dow University of Health Sciences, Karachi, Pakistan
| |
Collapse
|
218
|
Heese K. Gastrodia elata Blume (Tianma): Hope for Brain Aging and Dementia. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2020; 2020:8870148. [PMID: 33424999 PMCID: PMC7781687 DOI: 10.1155/2020/8870148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/26/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022]
Abstract
Since aging-related diseases, including dementia, represent major public health threats to our society, physician-scientists must develop innovative, interdisciplinary strategies to open new avenues for development of alternative therapies. One such novel approach may lie in traditional Chinese medicine (TCM). Gastrodia elata Blume (G. elata, tianma) is a TCM frequently used for treatment of cerebrocardiovascular diseases (CCVDs). Recent studies of G. elata-based treatment modalities, which have investigated its pharmacologically relevant activity, potential efficacy, and safety, have employed G. elata in well-characterized, aging-related disease models, with a focus on models of aging-related dementia, such as Alzheimer's disease (AD). Here, I examine results from previous studies of G. elata, as well as related herbal preparations and pure natural products, as prophylaxis and remedies for aging-related CCVDs and dementia. Concluding, data suggest that tianma treatment may be used as a promising complementary therapy for AD.
Collapse
Affiliation(s)
- Klaus Heese
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133791, Republic of Korea
| |
Collapse
|
219
|
Colnaghi L, Rondelli D, Muzi-Falconi M, Sertic S. Tau and DNA Damage in Neurodegeneration. Brain Sci 2020; 10:E946. [PMID: 33297375 PMCID: PMC7762255 DOI: 10.3390/brainsci10120946] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/29/2020] [Accepted: 12/02/2020] [Indexed: 12/11/2022] Open
Abstract
Neurodegenerative disorders are a family of incurable conditions. Among them, Alzheimer's disease and tauopathies are the most common. Pathological features of these two disorders are synaptic loss, neuronal cell death and increased DNA damage. A key pathological protein for the onset and progression of the conditions is the protein tau, a microtubule-binding protein highly expressed in neurons and encoded by the MAPT (microtubule-associated protein tau) gene. Tau is predominantly a cytosolic protein that interacts with numerous other proteins and molecules. Recent findings, however, have highlighted new and unexpected roles for tau in the nucleus of neuronal cells. This review summarizes the functions of tau in the metabolism of DNA, describing them in the context of the disorders.
Collapse
Affiliation(s)
- Luca Colnaghi
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Negri 2, 20156 Milan, Italy
| | - Diego Rondelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy; (D.R.); (M.M.-F.)
| | - Marco Muzi-Falconi
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy; (D.R.); (M.M.-F.)
| | - Sarah Sertic
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy; (D.R.); (M.M.-F.)
| |
Collapse
|
220
|
Gauthier S, Therriault J, Pascoal T, Rosa-Neto P. Impact of p-tau181 and p-tau217 levels on enrollment for randomized clinical trials and future use of anti-amyloid and anti-tau drugs. Expert Rev Neurother 2020; 20:1211-1213. [PMID: 33094676 DOI: 10.1080/14737175.2020.1841637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Serge Gauthier
- McGill Center for Studies in Aging , Montreal, QC, Canada
| | | | | | | |
Collapse
|
221
|
Morphine and HIV-1 Tat interact to cause region-specific hyperphosphorylation of tau in transgenic mice. Neurosci Lett 2020; 741:135502. [PMID: 33202259 DOI: 10.1016/j.neulet.2020.135502] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 12/24/2022]
Abstract
Opiate abuse is prevalent among HIV-infected individuals and may exacerbate HIV-associated age-related neurocognitive disorders. However, the extent to which HIV and opiates converge to accelerate pathological traits indicative of brain aging remains unknown. The pathological phospho-isotypes of tau (pSer396, pSer404, pThr205, pSer202, and pThr181) and the tau kinases GSK3β and CDK5/p35 were explored in the striatum, hippocampus, and prefrontal cortex of inducible male and female HIV-1 Tat-transgenic mice, with some receiving escalating doses of morphine for 2 weeks. In the striatum of male mice, pSer396 was increased by co-exposure to morphine and Tat as compared to all other groups. Striatal pSer404 and pThr205 were increased by Tat alone, while pSer202 and pThr181 were unchanged. A comparison between Tat-transgenic female and male mice revealed disparate outcomes for pThr205. No other sex-related changes to tau phosphorylation were observed. In the hippocampus, Tat increased pSer396, while other phosphorylation sites were unchanged and pSer202 was not detected. In the prefrontal cortex, morphine increased pSer396 levels, which were unaffected by Tat, while other phosphorylation sites were unaffected. Assessment of tau kinases revealed no changes to striatal GSK3β (phosphorylated or total) or the total CDK5 levels. Striatal levels of phosphorylated CDK5 and p35, the activator of CDK5, were increased by Tat and with morphine co-exposure, respectively. P35 levels positively correlated with those of pSer396 with Tat and morphine co-exposure. The results reveal region-specific hyperphosphorylation of tau induced by exposure to morphine, Tat, and unique morphine and Tat interactions.
Collapse
|
222
|
Phan LMT, Hoang TX, Vo TAT, Kim JY, Lee SM, Cho WW, Kim YH, Choi SH, Cho S. Nanobiosensors for Non-Amyloidbeta-Tau Biomarkers as Advanced Reporters of Alzheimer's Disease. Diagnostics (Basel) 2020; 10:E913. [PMID: 33171630 PMCID: PMC7695150 DOI: 10.3390/diagnostics10110913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 11/17/2022] Open
Abstract
Emerging nanomaterials providing benefits in sensitivity, specificity and cost-effectiveness are being widely investigated for biosensors in the application of Alzheimer's disease (AD) diagnosis. Core biomarkers amyloid-beta (Aβ) and Tau have been considered as key neuropathological hallmarks of AD. However, they did not sufficiently reflect clinical severity and therapeutic response, proving the difficulty of the Aβ- and Tau-targeting therapies in clinical trials. In recent years, there has still been a shortage of sensors for non-Aβ-Tau pathophysiological biomarkers that serve as advanced reporters for the early diagnosis of AD, predict AD progression, and monitor the treatment response. Nanomaterial-based sensors measuring multiple non-Aβ-Tau biomarkers could improve the capacity of AD progression characterization and supervised treatment, facilitating the comprehensive management of AD. This is the first review to principally represent current nanobiosensors for non-Aβ-Tau biomarker and that strategically deliberates future perspectives on the merit of non-Aβ-Tau biomarkers, in combination with Aβ and Tau, for the accurate diagnosis and prognosis of AD.
Collapse
Affiliation(s)
- Le Minh Tu Phan
- Department of Electronic Engineering, Gachon University, Seongnam-si 13120, Gyeonggi-do, Korea
- School of Medicine and Pharmacy, The University of Danang, Danang 550000, Vietnam
| | - Thi Xoan Hoang
- Department of Life Science, Gachon University, Seongnam 461-701, Gyeonggi-do, Korea; (T.X.H.); (T.A.T.V.); (J.Y.K.)
| | - Thuy Anh Thu Vo
- Department of Life Science, Gachon University, Seongnam 461-701, Gyeonggi-do, Korea; (T.X.H.); (T.A.T.V.); (J.Y.K.)
| | - Jae Young Kim
- Department of Life Science, Gachon University, Seongnam 461-701, Gyeonggi-do, Korea; (T.X.H.); (T.A.T.V.); (J.Y.K.)
| | - Sang-Myung Lee
- Cantis Inc., Ansan-si 15588, Gyeonggi-do, Korea; (S.-M.L.); (W.W.C.)
| | - Won Woo Cho
- Cantis Inc., Ansan-si 15588, Gyeonggi-do, Korea; (S.-M.L.); (W.W.C.)
| | - Young Hyo Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Inha University, Incheon 22332, Korea;
| | - Seong Hye Choi
- Department of Neurology, School of Medicine, Inha University, Incheon 22332, Korea;
| | - Sungbo Cho
- Department of Electronic Engineering, Gachon University, Seongnam-si 13120, Gyeonggi-do, Korea
- Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea
| |
Collapse
|
223
|
Retinal Degeneration and Alzheimer's Disease: An Evolving Link. Int J Mol Sci 2020; 21:ijms21197290. [PMID: 33023198 PMCID: PMC7582766 DOI: 10.3390/ijms21197290] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) and glaucoma are degenerative conditions of the retina and a significant cause of irreversible blindness in developed countries. Alzheimer’s disease (AD), the most common dementia of the elderly, is often associated with AMD and glaucoma. The cardinal features of AD include extracellular accumulation of amyloid β (Aβ) and intracellular deposits of hyper-phosphorylated tau (p-tau). Neuroinflammation and brain iron dyshomeostasis accompany Aβ and p-tau deposits and, together, lead to progressive neuronal death and dementia. The accumulation of Aβ and iron in drusen, the hallmark of AMD, and Aβ and p-tau in retinal ganglion cells (RGC), the main retinal cell type implicated in glaucoma, and accompanying inflammation suggest overlapping pathology. Visual abnormalities are prominent in AD and are believed to develop before cognitive decline. Some are caused by degeneration of the visual cortex, while others are due to RGC loss or AMD-associated retinal degeneration. Here, we review recent information on Aβ, p-tau, chronic inflammation, and iron dyshomeostasis as common pathogenic mechanisms linking the three degenerative conditions, and iron chelation as a common therapeutic option for these disorders. Additionally discussed is the role of prion protein, infamous for prion disorders, in Aβ-mediated toxicity and, paradoxically, in neuroprotection.
Collapse
|