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Zhang X, Xia M, Wu Y, Zhang F. Branched-Chain Amino Acids Metabolism and Their Roles in Retinopathy: From Relevance to Mechanism. Nutrients 2023; 15:2161. [PMID: 37432261 DOI: 10.3390/nu15092161] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 04/20/2023] [Accepted: 04/27/2023] [Indexed: 07/12/2023] Open
Abstract
Retinopathy is one of the leading causes of irreversible blindness and vision loss worldwide. Imbalanced nutrients play important roles in the pathogenesis and pathophysiology of retinal diseases. Branched-Chain Amino Acids (BCAAs), as essential amino acids, perform a variety of biological functions, including protein synthesis, glucose metabolism, lipid metabolism, inflammation, and oxidative stress in metabolic tissues of diabetes and aging-related diseases. Recently, it has been shown that BCAAs are highly related to neuroprotection, oxidative stress, inflammatory and glutamate toxicity in the retina of retinopathy. Therefore, this review summarizes the alterations of BCAA levels in retinopathy, especially diabetic retinopathy and aging-related macular disease, and the genetics, functions, and mechanisms of BCAAs in the retina as well as other metabolic tissues for reference. All of these efforts aim to provide fundamental knowledge of BCAAs for further discoveries and research on retina health based on the sensing and signaling of essential amino acids.
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Affiliation(s)
- Xiaonan Zhang
- National Clinical Research Center for Eye Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Liaoning Provence Key Laboratory of Genome Engineered Animal Models, National Center of Genetically Engineered Animal Models for International Research, Institute for Genome Engineered Animal Models of Human Diseases, Dalian Medical University, Dalian 116000, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
| | - Mengxue Xia
- National Clinical Research Center for Eye Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
| | - Yingjie Wu
- Liaoning Provence Key Laboratory of Genome Engineered Animal Models, National Center of Genetically Engineered Animal Models for International Research, Institute for Genome Engineered Animal Models of Human Diseases, Dalian Medical University, Dalian 116000, China
- Shandong Provincial Hospital, School of Laboratory Animal & Shandong Laboratory Animal Center, Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250021, China
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA
| | - Fang Zhang
- National Clinical Research Center for Eye Diseases, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
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2
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Chau DDL, Li W, Chan WWR, Sun JKL, Zhai Y, Chow HM, Lau KF. Insulin stimulates atypical protein kinase C-mediated phosphorylation of the neuronal adaptor FE65 to potentiate neurite outgrowth by activating ARF6-Rac1 signaling. FASEB J 2022; 36:e22594. [PMID: 36250347 DOI: 10.1096/fj.202200757r] [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: 05/18/2022] [Revised: 08/21/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022]
Abstract
Neurite outgrowth is a fundamental process in neurons that produces extensions and, consequently, neural connectivity. Neurite damage and atrophy are observed in various brain injuries and disorders. Understanding the intrinsic pathways of neurite outgrowth is essential for developing strategies to stimulate neurite regeneration. Insulin is a pivotal hormone in the regulation of glucose homeostasis. There is increasing evidence for the neurotrophic functions of insulin, including the induction of neurite outgrowth. However, the associated mechanism remains elusive. Here, we demonstrate that insulin potentiates neurite outgrowth mediated by the small GTPases ADP-ribosylation factor 6 (ARF6) and Ras-related C3 botulinum toxin substrate 1 (Rac1) through the neuronal adaptor FE65. Moreover, insulin enhances atypical protein kinase Cι/λ (PKCι/λ) activation and FE65 phosphorylation at serine 459 (S459) in neurons and mouse brains. In vitro and cellular assays show that PKCι/λ phosphorylated FE65 at S459. Consistently, insulin potentiates FE65 S459 phosphorylation only in the presence of PKCι/λ. Phosphomimetic studies show that an FE65 S459E mutant potently activates ARF6, Rac1, and neurite outgrowth. Notably, this phosphomimetic mutation enhances the FE65-ARF6 interaction, a process that promotes ARF6-Rac1-mediated neurite outgrowth. Likewise, insulin treatment and PKCι/λ overexpression potentiate the FE65-ARF6 interaction. Conversely, PKCι/λ knockdown suppresses the stimulatory effect of FE65 on ARF6-Rac1-mediated neurite outgrowth. The effect of insulin on neurite outgrowth is also markedly attenuated in PKCι/λ knockdown neurons, in the presence and absence of FE65. Our findings reveal a novel mechanism linking insulin with ARF6-Rac1-dependent neurite extension through the PKCι/λ-mediated phosphorylation of FE65.
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Affiliation(s)
- Dennis Dik-Long Chau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Wen Li
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China.,Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wai Wa Ray Chan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Jacquelyne Ka-Li Sun
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Yuqi Zhai
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Hei-Man Chow
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
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The Roles of Par3, Par6, and aPKC Polarity Proteins in Normal Neurodevelopment and in Neurodegenerative and Neuropsychiatric Disorders. J Neurosci 2022; 42:4774-4793. [PMID: 35705493 DOI: 10.1523/jneurosci.0059-22.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 11/21/2022] Open
Abstract
Normal neural circuits and functions depend on proper neuronal differentiation, migration, synaptic plasticity, and maintenance. Abnormalities in these processes underlie various neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Neural development and maintenance are regulated by many proteins. Among them are Par3, Par6 (partitioning defective 3 and 6), and aPKC (atypical protein kinase C) families of evolutionarily conserved polarity proteins. These proteins perform versatile functions by forming tripartite or other combinations of protein complexes, which hereafter are collectively referred to as "Par complexes." In this review, we summarize the major findings on their biophysical and biochemical properties in cell polarization and signaling pathways. We next summarize their expression and localization in the nervous system as well as their versatile functions in various aspects of neurodevelopment, including neuroepithelial polarity, neurogenesis, neuronal migration, neurite differentiation, synaptic plasticity, and memory. These versatile functions rely on the fundamental roles of Par complexes in cell polarity in distinct cellular contexts. We also discuss how cell polarization may correlate with subcellular polarization in neurons. Finally, we review the involvement of Par complexes in neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease. While emerging evidence indicates that Par complexes are essential for proper neural development and maintenance, many questions on their in vivo functions have yet to be answered. Thus, Par3, Par6, and aPKC continue to be important research topics to advance neuroscience.
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4
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Jellinger KA. Heterogeneity of Multiple System Atrophy: An Update. Biomedicines 2022; 10:599. [PMID: 35327402 PMCID: PMC8945102 DOI: 10.3390/biomedicines10030599] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/24/2022] [Accepted: 03/02/2022] [Indexed: 02/04/2023] Open
Abstract
Multiple system atrophy (MSA) is a fatal, rapidly progressing neurodegenerative disease of uncertain etiology, clinically characterized by various combinations of Levodopa unresponsive parkinsonism, cerebellar, autonomic and motor dysfunctions. The morphological hallmark of this α-synucleinopathy is the deposition of aberrant α-synuclein in both glia, mainly oligodendroglia (glial cytoplasmic inclusions /GCIs/) and neurons, associated with glioneuronal degeneration of the striatonigral, olivopontocerebellar and many other neuronal systems. Typical phenotypes are MSA with predominant parkinsonism (MSA-P) and a cerebellar variant (MSA-C) with olivocerebellar atrophy. However, MSA can present with a wider range of clinical and pathological features than previously thought. In addition to rare combined or "mixed" MSA, there is a broad spectrum of atypical MSA variants, such as those with a different age at onset and disease duration, "minimal change" or prodromal forms, MSA variants with Lewy body disease or severe hippocampal pathology, rare forms with an unusual tau pathology or spinal myoclonus, an increasing number of MSA cases with cognitive impairment/dementia, rare familial forms, and questionable conjugal MSA. These variants that do not fit into the current classification of MSA are a major challenge for the diagnosis of this unique proteinopathy. Although the clinical diagnostic accuracy and differential diagnosis of MSA have improved by using combined biomarkers, its distinction from clinically similar extrapyramidal disorders with other pathologies and etiologies may be difficult. These aspects should be taken into consideration when revising the current diagnostic criteria. This appears important given that disease-modifying treatment strategies for this hitherto incurable disorder are under investigation.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Alberichgasse 5/13, A-1150 Vienna, Austria
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5
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Chau DDL, Lau KF. The roles of atypical protein kinase Cs (aPKCs) in the nervous system: targets for neuroregeneration? Neural Regen Res 2020; 15:1475-1476. [PMID: 31997808 PMCID: PMC7059589 DOI: 10.4103/1673-5374.274334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Dennis Dik-Long Chau
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Kwok-Fai Lau
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
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6
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aPKC in neuronal differentiation, maturation and function. Neuronal Signal 2019; 3:NS20190019. [PMID: 32269838 PMCID: PMC7104321 DOI: 10.1042/ns20190019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 12/17/2022] Open
Abstract
The atypical Protein Kinase Cs (aPKCs)—PRKCI, PRKCZ and PKMζ—form a subfamily within the Protein Kinase C (PKC) family. These kinases are expressed in the nervous system, including during its development and in adulthood. One of the aPKCs, PKMζ, appears to be restricted to the nervous system. aPKCs are known to play a role in a variety of cellular responses such as proliferation, differentiation, polarity, migration, survival and key metabolic functions such as glucose uptake, that are critical for nervous system development and function. Therefore, these kinases have garnered a lot of interest in terms of their functional role in the nervous system. Here we review the expression and function of aPKCs in neural development and in neuronal maturation and function. Despite seemingly paradoxical findings with genetic deletion versus gene silencing approaches, we posit that aPKCs are likely candidates for regulating many important neurodevelopmental and neuronal functions, and may be associated with a number of human neuropsychiatric diseases.
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7
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Guzman-Martinez L, Maccioni RB, Andrade V, Navarrete LP, Pastor MG, Ramos-Escobar N. Neuroinflammation as a Common Feature of Neurodegenerative Disorders. Front Pharmacol 2019; 10:1008. [PMID: 31572186 PMCID: PMC6751310 DOI: 10.3389/fphar.2019.01008] [Citation(s) in RCA: 430] [Impact Index Per Article: 86.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 08/08/2019] [Indexed: 12/26/2022] Open
Abstract
Neurodegenerative diseases share the fact that they derive from altered proteins that undergo an unfolding process followed by formation of β-structures and a pathological tendency to self-aggregate in neuronal cells. This is a characteristic of tau protein in Alzheimer’s disease and several tauopathies associated with tau unfolding, α-synuclein in Parkinson’s disease, and huntingtin in Huntington disease. Usually, the self-aggregation products are toxic to these cells, and toxicity spreads all over different brain areas. We have postulated that these protein unfolding events are the molecular alterations that trigger several neurodegenerative disorders. Most interestingly, these events occur as a result of neuroinflammatory cascades involving alterations in the cross-talks between glial cells and neurons as a consequence of the activation of microglia and astrocytes. The model we have hypothesized for Alzheimer’s disease involves damage signals that promote glial activation, followed by nuclear factor NF-kβ activation, synthesis, and release of proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, and IL-12 that affect neuronal receptors with an overactivation of protein kinases. These patterns of pathological events can be applied to several neurodegenerative disorders. In this context, the involvement of innate immunity seems to be a major paradigm in the pathogenesis of these diseases. This is an important element for the search for potential therapeutic approaches for all these brain disorders.
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Affiliation(s)
- Leonardo Guzman-Martinez
- Laboratory of Neuroscience, Faculty of Sciences, University of Chile & International Center for Biomedicine (ICC), Santiago, Chile
| | - Ricardo B Maccioni
- Laboratory of Neuroscience, Faculty of Sciences, University of Chile & International Center for Biomedicine (ICC), Santiago, Chile.,Department of Neurological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Víctor Andrade
- Laboratory of Neuroscience, Faculty of Sciences, University of Chile & International Center for Biomedicine (ICC), Santiago, Chile
| | - Leonardo Patricio Navarrete
- Laboratory of Neuroscience, Faculty of Sciences, University of Chile & International Center for Biomedicine (ICC), Santiago, Chile
| | - María Gabriela Pastor
- Laboratory of Neuroscience, Faculty of Sciences, University of Chile & International Center for Biomedicine (ICC), Santiago, Chile.,Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Nicolas Ramos-Escobar
- Laboratory of Neuroscience, Faculty of Sciences, University of Chile & International Center for Biomedicine (ICC), Santiago, Chile
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Lachén-Montes M, González-Morales A, Schvartz D, Zelaya MV, Ausin K, Fernández-Irigoyen J, Sánchez JC, Santamaría E. The olfactory bulb proteotype differs across frontotemporal dementia spectrum. J Proteomics 2019; 201:37-47. [PMID: 30999060 DOI: 10.1016/j.jprot.2019.04.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/08/2019] [Accepted: 04/13/2019] [Indexed: 12/12/2022]
Abstract
Mild olfactory dysfunction has been observed in frontotemporal dementias (FTD). However, the underlying molecular mechanisms associated to this deficit are poorly understood. We applied quantitative proteomics to analyze pathological effects on the olfactory bulb (OB) from progressive supranuclear palsy (PSP) and frontotemporal lobar degeneration (FTLD-TDP43) subjects respect to elderly non-FTD group. Our data revealed: i) a mitochondrial and calcium homeostasis impairment in PSP and ii) a disruption of protein synthesis and vesicle trafficking in FTLD-TDP43. Although differential OB proteomes clearly differ between both FTD phenotypes, functional analyses pointed out an imbalance in survival signaling in both pathologies. A common alteration of olfactory mitogen-activated protein kinases (MAPKs), calcium/calmodulin dependent protein kinase II (CAMKII), and protein kinase C (PKC) signaling pathways was observed in PSP and FTLD subjects. In contrast, a specific shut off in mitogen-activated protein kinase kinase 4 (SEK1/MKK4)/stress-activated protein kinase (SAPK) axis was exclusively observed in PSP, whereas a specific phosphoinositide-dependent protein kinase 1 (PDK1) inactivation was observed in FTLD-TDP43. In summary, our data contribute to a better understanding of the molecular mechanisms that are modulated in PSP and FTLD-TDP43 at olfactory level, highlighting cross-disease similarities and differences in the regulation of survival pathways across FTD spectrum. SIGNIFICANCE: This work reflects differential olfactory molecular disarrangements in PSP and FTLD-TDP43, two clinically similar FTD disorders, but with different neuropathological signature. Besides FTDs present mild olfactory dysfunction, our data provide basic information for understanding the implication of the OB in the pathophysiology of FTDs.
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Affiliation(s)
- Mercedes Lachén-Montes
- Clinical Neuroproteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea, 3, 31008 Pamplona, Spain; Proteored-ISCIII, Proteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea 3, 31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, Irunlarrea 3, 31008 Pamplona, Spain
| | - Andrea González-Morales
- Clinical Neuroproteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea, 3, 31008 Pamplona, Spain; Proteored-ISCIII, Proteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea 3, 31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, Irunlarrea 3, 31008 Pamplona, Spain
| | - Domitille Schvartz
- Translational Biomarker Group, Department of Human Protein Sciences, University of Geneva, Rue Michel Servet 1, 1211 Geneve 4, Switzerland
| | - María Victoria Zelaya
- Clinical Neuroproteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea, 3, 31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, Irunlarrea 3, 31008 Pamplona, Spain; Pathological Anatomy Department, Complejo Hospitalario de Navarra (CHN), Pamplona, Spain
| | - Karina Ausin
- Proteored-ISCIII, Proteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea 3, 31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, Irunlarrea 3, 31008 Pamplona, Spain
| | - Joaquín Fernández-Irigoyen
- Clinical Neuroproteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea, 3, 31008 Pamplona, Spain; Proteored-ISCIII, Proteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea 3, 31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, Irunlarrea 3, 31008 Pamplona, Spain
| | - Jean Charles Sánchez
- Translational Biomarker Group, Department of Human Protein Sciences, University of Geneva, Rue Michel Servet 1, 1211 Geneve 4, Switzerland
| | - Enrique Santamaría
- Clinical Neuroproteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea, 3, 31008 Pamplona, Spain; Proteored-ISCIII, Proteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Pública de Navarra (UPNA), Irunlarrea 3, 31008 Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, Spain, Irunlarrea 3, 31008 Pamplona, Spain.
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9
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Neuroimmune Tau Mechanisms: Their Role in the Progression of Neuronal Degeneration. Int J Mol Sci 2018; 19:ijms19040956. [PMID: 29570615 PMCID: PMC5979395 DOI: 10.3390/ijms19040956] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/05/2018] [Accepted: 03/08/2018] [Indexed: 12/15/2022] Open
Abstract
Progressive neurodegenerative pathologies in aged populations are an issue of major concern worldwide. The microtubule-associated protein tau is able to self-aggregate to form abnormal supramolecular structures that include small oligomers up to complex polymers. Tauopathies correspond to a group of diseases that share tau pathology as a common etiological agent. Since microglial cells play a preponderant role in innate immunity and are the main source of proinflammatory factors in the central nervous system (CNS), the alterations in the cross-talks between microglia and neuronal cells are the main focus of studies concerning the origins of tauopathies. According to evidence from a series of studies, these changes generate a feedback mechanism reactivating microglia and provoking constant cellular damage. Thus, the previously summarized mechanisms could explain the onset and progression of different tauopathies and their functional/behavioral effects, opening the window towards an understanding of the molecular basis of anomalous tau interactions. Despite clinical and pathological differences, increasing experimental evidence indicates an overlap between tauopathies and synucleinopathies, considering that neuroinflammatory events are involved and the existence of protein misfolding. Neurofibrillary tangles of pathological tau (NFT) and Lewy bodies appear to coexist in certain brain areas. Thus, the co-occurrence of synucleinopathies with tauopathies is evidenced by several investigations, in which NFT were found in the substantia nigra of patients with Parkinson’s disease, suggesting that the pathologies share some common features at the level of neuroinflammatory events.
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Sukumaran P, Sun Y, Antonson N, Singh BB. Dopaminergic neurotoxins induce cell death by attenuating NF-κB-mediated regulation of TRPC1 expression and autophagy. FASEB J 2018; 32:1640-1652. [PMID: 29150520 DOI: 10.1096/fj.201700662rr] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Alterations in Ca2+ homeostasis affect neuronal survival. However, the identity of Ca2+ channels and the mechanisms underlying neurotoxin-induced neuronal degeneration are not well understood. In this study, the dopaminergic neurotoxins 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridium ions (MPP+)/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which mimic Parkinson's disease (PD), induced neuronal degeneration by decreasing store-mediated Ca2+ entry. The function of the transient receptor potential canonical (TRPC)-1 channel was decreased upon exposure to the neurotoxins, followed by a decrease in TRPC1 expression. Similar to neurotoxins, samples from patients with PD exhibited attenuated TRPC1 expression, which was accompanied by a decrease in autophagic markers and a subsequent increase in apoptosis markers. Furthermore, exposure to neurotoxins attenuated PKC phosphorylation, decreased expression of autophagic markers, and increased apoptosis in SHSY-5Y neuroblastoma cells, which was again dependent on TRPC1. Prolonged neurotoxin treatment attenuated the binding of NF-κB to the TRPC1 promoter, which resulted in a decrease in TRPC1 expression, thereby attenuating autophagy and activating cell death. Restoration of TRPC1 expression rescued the effects of the dopaminergic neurotoxins in neuroblastoma cells by increasing Ca2+ entry, restoring NF-κB activity, and promoting autophagy. Overall, these results suggest that dopaminergic neurotoxins initially decreased Ca2+ entry, which inhibited the binding of NF-κB to the TRPC1 promoter, thereby inhibiting TRPC1 expression and resulting in cell death by preventing autophagy.-Sukumaran, P., Sun, Y., Antonson, N., Singh, B. B. Dopaminergic neurotoxins induce cell death by attenuating NF-κB-mediated regulation of TRPC1 expression and autophagy.
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Affiliation(s)
- Pramod Sukumaran
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Yuyang Sun
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Neil Antonson
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
| | - Brij B Singh
- Department of Biomedical Science, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, USA
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11
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Jellinger KA. Neuropathology of multiple system atrophy: New thoughts about pathogenesis. Mov Disord 2014; 29:1720-41. [DOI: 10.1002/mds.26052] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 08/29/2014] [Accepted: 09/16/2014] [Indexed: 12/14/2022] Open
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12
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Multiple system atrophy: a prototypical synucleinopathy for disease-modifying therapeutic strategies. Neurobiol Dis 2014; 67:133-9. [PMID: 24727096 DOI: 10.1016/j.nbd.2014.03.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/24/2014] [Accepted: 03/31/2014] [Indexed: 02/08/2023] Open
Abstract
Despite active fundamental, translational and clinical research, no therapeutic intervention has yet shown convincing effects on disease progression in Parkinson's disease (PD) patients. Indeed, several disease-modification trials failed or proved to be inconclusive due to lack of consistency between clinical rating scales and putative surrogate markers of disease progression, or confounding symptomatic effects of the tested compound. Multiple system atrophy (MSA) is a rapidly progressing orphan disorder leading to severe motor disability within a few years. Together with PD and dementia with Lewy bodies (DLB), MSA belongs to the synucleinopathies, a group of neurodegenerative disorders characterized by the abnormal accumulation of alpha-synuclein. Crucial milestones have been reached for successfully conducting clinical intervention trials in a large number of patients with MSA. In this personal view, we will review evidence, and discuss why MSA could prove the most relevant clinical model for assessing treatments that target mechanisms operating in all synucleinopathies.
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13
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Tury A, Tolentino K, Zou Y. Altered expression of atypical PKC and Ryk in the spinal cord of a mouse model of amyotrophic lateral sclerosis. Dev Neurobiol 2014; 74:839-50. [PMID: 24123880 DOI: 10.1002/dneu.22137] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/24/2013] [Accepted: 09/25/2013] [Indexed: 11/09/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive paralysis due to the selective death of motor neurons of unknown causes. Increasing evidence indicates that Wnt signaling is altered in ALS. In this study, we focused on two non-canonical Wnt signaling components, atypical PKC (aPKC) and a Wnt receptor, Ryk, in a mouse model of ALS, SOD1 (G93A). aPKC mediates Wnt signaling to regulate growth cone guidance, axon differentiation and cell survival. Ryk is a Wnt repulsive receptor that regulates axon guidance and inhibits regeneration after spinal cord injury. aPKC expression was increased in motor neurons of the lumbar spinal cord in SOD1 (G93A) mice at both early and late stages. Interestingly, aPKC was co-localized with SOD1 in motor neuron cell bodies and extracellular aggregates, and aPKC-containing extracellular aggregates increased with disease progression. Biochemical fractionation showed that aPKC protein level was increased in the detergent-insoluble protein fraction in SOD1 (G93A) mice at late stage but decreased in the detergent-soluble fraction at symptomatic stage. These results suggest that aPKC may be sequestered in SOD1 aggregates, impairing its ability to protect motor neurons from death. Ryk expression was also increased in the motor neurons and the white matter in the ventral lumbar spinal cord of mutant SOD1 mice with a peak at early stage. These observations indicate that Wnt/aPKC and Wnt/Ryk signaling are altered in SOD1 (G93A) mice, suggesting that changed Wnt signaling may contribute to neurodegeneration in ALS.
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Affiliation(s)
- Anna Tury
- University of California, San Diego, Division of Biological Sciences, Section of Neurobiology, 9500 Gilman Drive, La Jolla, California, 92093
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14
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Seibenhener ML, Zhao T, Du Y, Calderilla-Barbosa L, Yan J, Jiang J, Wooten MW, Wooten MC. Behavioral effects of SQSTM1/p62 overexpression in mice: support for a mitochondrial role in depression and anxiety. Behav Brain Res 2013; 248:94-103. [PMID: 23591541 DOI: 10.1016/j.bbr.2013.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 04/01/2013] [Accepted: 04/06/2013] [Indexed: 11/18/2022]
Abstract
Affective spectrum and anxiety disorders have come to be recognized as the most prevalently diagnosed psychiatric disorders. Among a suite of potential causes, changes in mitochondrial energy metabolism and function have been associated with such disorders. Thus, proteins that specifically change mitochondrial functionality could be identified as molecular targets for drugs related to treatment for affective spectrum disorders. Here, we report generation of transgenic mice overexpressing the scaffolding and mitophagy related protein Sequestosome1 (SQSTM1/p62) or a single point mutant (P392L) in the UBA domain of SQSTM1/p62. We show that overexpression of SQSTM1/p62 increases mitochondrial energy output and improves transcription factor import into the mitochondrial matrix. These elevated levels of mitochondrial functionality correlate directly with discernible improvements in mouse behaviors related to affective spectrum and anxiety disorders. We also describe how overexpression of SQSTM1/p62 improves spatial learning and long term memory formation in these transgenic mice. These results suggest that SQSTM1/p62 provides an attractive target for therapeutic agents potentially suitable for the treatment of anxiety and affective spectrum disorders.
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Affiliation(s)
- M Lamar Seibenhener
- Dept. Biological Sciences, Auburn University, 331 Funchess Hall, Auburn, AL 36832, USA.
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Nouar R, Devred F, Breuzard G, Peyrot V. FRET and FRAP imaging: approaches to characterise tau and stathmin interactions with microtubules in cells. Biol Cell 2013; 105:149-61. [PMID: 23312015 DOI: 10.1111/boc.201200060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 01/09/2013] [Indexed: 12/13/2022]
Abstract
Microtubules (MTs) are involved in many crucial processes such as cell morphogenesis, mitosis and motility. These dynamic structures resulting from the complex assembly of tubulin are tightly regulated by stabilising MT-associated proteins (MAPs) such as tau and destabilising proteins, notably stathmin. Because of their key role, these MAPs and their interactions have been extensively studied using biochemical and biophysical approaches, particularly in vitro. Nevertheless, numerous questions remain unanswered and the mechanisms of interaction between MT and these proteins are still unclear in cells. Techniques coupling cell imaging and fluorescence methods, such as Förster resonance energy transfer and fluorescence recovery after photobleaching, are excellent tools to study these interactions in situ. After describing these methods, we will present emblematic data from the literature and unpublished experimental results from our laboratory concerning the interactions between MTs, tau and stathmin in cells.
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Affiliation(s)
- Roqiya Nouar
- INSERM UMR 911, Aix-Marseille Université, CRO2, 13385, Marseille, France
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Jellinger KA. Interaction between pathogenic proteins in neurodegenerative disorders. J Cell Mol Med 2012; 16:1166-83. [PMID: 22176890 PMCID: PMC3823071 DOI: 10.1111/j.1582-4934.2011.01507.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 12/16/2011] [Indexed: 12/21/2022] Open
Abstract
The misfolding and progressive aggregation of specific proteins in selective regions of the nervous system is a seminal occurrence in many neurodegenerative disorders, and the interaction between pathological/toxic proteins to cause neurodegeneration is a hot topic of current neuroscience research. Despite clinical, genetic and experimental differences, increasing evidence indicates considerable overlap between synucleinopathies, tauopathies and other protein-misfolding diseases. Inclusions, often characteristic hallmarks of these disorders, suggest interactions of pathological proteins enganging common downstream pathways. Novel findings that have shifted our understanding in the role of pathologic proteins in the pathogenesis of Alzheimer, Parkinson, Huntington and prion diseases, have confirmed correlations/overlaps between these and other neurodegenerative disorders. Emerging evidence, in addition to synergistic effects of tau protein, amyloid-β, α-synuclein and other pathologic proteins, suggests that prion-like induction and spreading, involving secreted proteins, are major pathogenic mechanisms in various neurodegenerative diseases, depending on genetic backgrounds and environmental factors. The elucidation of the basic molecular mechanisms underlying the interaction and spreading of pathogenic proteins, suggesting a dualism or triad of neurodegeneration in protein-misfolding disorders, is a major challenge for modern neuroscience, to provide a deeper insight into their pathogenesis as a basis of effective diagnosis and treatment.
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Bellucci A, Zaltieri M, Navarria L, Grigoletto J, Missale C, Spano P. From α-synuclein to synaptic dysfunctions: new insights into the pathophysiology of Parkinson's disease. Brain Res 2012; 1476:183-202. [PMID: 22560500 DOI: 10.1016/j.brainres.2012.04.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 03/30/2012] [Accepted: 04/09/2012] [Indexed: 10/28/2022]
Abstract
Alpha-synuclein is a natively unfolded protein playing a key role in the regulation of several neuronal synaptic functions in physiological and pathological conditions. Many studies, over the past years, have shown that it is actively involved in PD pathophysiology. Alpha-synuclein is integrated in a complex network of neuronal processes through the interaction with cytosolic and synaptic proteins. Hence, it is not the sole α-synuclein pathology but its effects on diverse protein partners and specific cellular pathways in the membrane and/or cytosolic districts such as endoplasmic reticulum/Golgi, axonal and synaptic compartments of dopaminergic neurons, that may cause the onset of neuronal cell dysfunction and degeneration which are among the key pathological features of the PD brain. Here we summarize a series of experimental data supporting that α-synuclein aggregation may induce dysfunction and degeneration of synapses via these multiple mechanisms. Taken together, these data add new insights into the complex mechanisms underlying synaptic derangement in PD and other α-synucleinopathies. This article is part of a Special Issue entitled: Brain Integration.
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Affiliation(s)
- Arianna Bellucci
- Division of Pharmacology, Department of Biomedical Sciences and Biotechnologies and National Institute of Neuroscience, University of Brescia, Brescia, Italy.
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Abstract
AbstractGenetic, neuropathological and biochemical evidence implicates α-synuclein, a 140 amino acid presynaptic neuronal protein, in the pathogenesis of Parkinson’s disease and other neurodegenerative disorders. The aggregated protein inclusions mainly containing aberrant α-synuclein are widely accepted as morphological hallmarks of α-synucleinopathies, but their composition and location vary between disorders along with neuronal networks affected. α-Synuclein exists physiologically in both soluble and membran-bound states, in unstructured and α-helical conformations, respectively, while posttranslational modifications due to proteostatic deficits are involved in β-pleated aggregation resulting in formation of typical inclusions. The physiological function of α-synuclein and its role linked to neurodegeneration, however, are incompletely understood. Soluble oligomeric, not fully fibrillar α-synuclein is thought to be neurotoxic, main targets might be the synapse, axons and glia. The effects of aberrant α-synuclein include alterations of calcium homeostasis, mitochondrial dysfunction, oxidative and nitric injuries, cytoskeletal effects, and neuroinflammation. Proteasomal dysfunction might be a common mechanism in the pathogenesis of neuronal degeneration in α-synucleinopathies. However, how α-synuclein induces neurodegeneration remains elusive as its physiological function. Genome wide association studies demonstrated the important role for genetic variants of the SNCA gene encoding α-synuclein in the etiology of Parkinson’s disease, possibly through effects on oxidation, mitochondria, autophagy, and lysosomal function. The neuropathology of synucleinopathies and the role of α-synuclein as a potential biomarker are briefly summarized. Although animal models provided new insights into the pathogenesis of Parkinson disease and multiple system atrophy, most of them do not adequately reproduce the cardinal features of these disorders. Emerging evidence, in addition to synergistic interactions of α-synuclein with various pathogenic proteins, suggests that prionlike induction and seeding of α-synuclein could lead to the spread of the pathology and disease progression. Intervention in the early aggregation pathway, aberrant cellular effects, or secretion of α-synuclein might be targets for neuroprotection and disease-modifying therapy.
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Ha S, Furukawa R, Fechheimer M. Association of AICD and Fe65 with Hirano bodies reduces transcriptional activation and initiation of apoptosis. Neurobiol Aging 2011; 32:2287-98. [PMID: 20133016 PMCID: PMC2894277 DOI: 10.1016/j.neurobiolaging.2010.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 12/22/2009] [Accepted: 01/07/2010] [Indexed: 02/03/2023]
Abstract
Hirano bodies are cytoplasmic inclusions predominantly found in the central nervous system associated with various conditions including aging and Alzheimer's disease (AD). Since most studies of Hirano bodies have been performed in post-mortem samples, the physiological roles of Hirano bodies have not been investigated. Astrocytoma H4 cells were employed to test the hypothesis that Hirano bodies interact with and modulate signaling by the C-terminal fragment of amyloid-β precursor protein (AICD). We demonstrated by immunofluorescence and immunoprecipitation that model Hirano bodies accumulate AICD. Since stimulation of transcription by AICD is dependent on its interaction with the nuclear adaptor protein Fe65, we examined localization of Fe65, and employed a dual luciferase reporter assay to test the effects of Hirano bodies on AICD- and Fe65-dependent modulation of gene expression. We find that both AICD and Fe65 are co-localized in model Hirano bodies. Model Hirano bodies also down-regulate both AICD-dependent apoptosis and AICD- and Fe65-dependent transcriptional activity. Thus, association of AICD and Fe65 with Hirano bodies impedes their function in promoting apoptosis and modulating transcription.
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Affiliation(s)
- Sangdeuk Ha
- Department of Cellular Biology, University of Georgia, Athens, GA 30602 USA
| | - Ruth Furukawa
- Department of Cellular Biology, University of Georgia, Athens, GA 30602 USA
| | - Marcus Fechheimer
- Department of Cellular Biology, University of Georgia, Athens, GA 30602 USA
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Jellinger KA. Neuropathology of sporadic Parkinson's disease: evaluation and changes of concepts. Mov Disord 2011; 27:8-30. [PMID: 22081500 DOI: 10.1002/mds.23795] [Citation(s) in RCA: 311] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 04/19/2011] [Accepted: 04/21/2011] [Indexed: 12/30/2022] Open
Abstract
Parkinson's disease (PD), one of the most frequent neurodegenerative disorders, is no longer considered a complex motor disorder characterized by extrapyramidal symptoms, but a progressive multisystem or-more correctly-multiorgan disease with variegated neurological and nonmotor deficiencies. It is morphologically featured not only by the degeneration of the dopaminergic nigrostriatal system, responsible for the core motor deficits, but by multifocal involvement of the central, peripheral and autonomic nervous system and other organs associated with widespread occurrence of Lewy bodies and dystrophic Lewy neurites. This results from deposition of abnormal α-synuclein (αSyn), the major protein marker of PD, and other synucleinopathies. Recent research has improved both the clinical and neuropathological diagnostic criteria of PD; it has further provided insights into the development and staging of αSyn and Lewy pathologies and has been useful in understanding the pathogenesis of PD. However, many challenges remain, for example, the role of Lewy bodies and the neurobiology of axons in the course of neurodegeneration, the relation between αSyn, Lewy pathology, and clinical deficits, as well as the interaction between αSyn and other pathologic proteins. Although genetic and experimental models have contributed to exploring the causes, pathomechanisms, and treatment options of PD, there is still a lack of an optimal animal model, and the etiology of this devastating disease is far from being elucidated.
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Jellinger KA. Interaction between α-synuclein and other proteins in neurodegenerative disorders. ScientificWorldJournal 2011; 11:1893-907. [PMID: 22125446 PMCID: PMC3217595 DOI: 10.1100/2011/371893] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 10/10/2011] [Indexed: 02/06/2023] Open
Abstract
Protein aggregation is a common characteristic of many neurodegenerative disorders, and the interaction between pathological/toxic proteins to cause neurodegeneration is a hot topic of current neuroscience research. Despite clinical, genetic, and experimental differences, evidence increasingly indicates considerable overlap between synucleinopathies and tauopathies or other protein-misfolding diseases. Inclusions, characteristics of these disorders, also occurring in other neurodegenerative diseases, suggest interactions of pathological proteins engaging common downstream pathways. Novel findings that have shifted our understanding in the role of pathologic proteins in the pathogenesis of Parkinson and Alzheimer diseases have confirmed correlations/overlaps between these and other neurodegenerative disorders. The synergistic effects of α-synuclein, hyperphosphorylated tau, amyloid-β, and other pathologic proteins, and the underlying molecular pathogenic mechanisms, including induction and spread of protein aggregates, are critically reviewed, suggesting a dualism or triad of neurodegeneration in protein-misfolding disorders, although the etiology of most of these processes is still mysterious.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Kenyongasse 18, A-1070 Vienna, Austria.
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Ha S, Furukawa R, Stramiello M, Wagner JJ, Fechheimer M. Transgenic mouse model for the formation of Hirano bodies. BMC Neurosci 2011; 12:97. [PMID: 21978358 PMCID: PMC3203848 DOI: 10.1186/1471-2202-12-97] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 10/06/2011] [Indexed: 12/28/2022] Open
Abstract
Background Hirano bodies are actin-rich cytoplasmic inclusions found predominantly in the brain in association with a variety of conditions including aging and Alzheimer's disease. The function of Hirano bodies in normal aging and in progression of disease has not been extensively investigated due to a lack of experimental model systems. We have developed a transgenic mouse model by expression of a gain-of-function actin cross-linking protein mutant. Results We used the Cre/loxP system to permit tissue specific expression of Hirano bodies, and employed the murine Thy 1 promoter to drive expression of Cre recombinase in the brain. Hirano bodies were observed in the cerebral cortex and hippocampus of homozygous double transgenic 6 month old mice containing Cre. The Hirano bodies were eosinophilic rods, and also exhibited the paracrystalline F-actin filament organization that is characteristic of these inclusions. Mice with Hirano bodies appear healthy and fertile, but exhibited some alterations in both short-term and long-term synaptic plasticity, including paired-pulse depression rather than facilitation, and decreased magnitude of early LTP. Conclusions Hirano bodies are not lethal and appear to have little or no effect on histology and tissue organization. Hirano bodies do modulate synaptic plasticity and exert clearly discernable effects on LTP and paired-pulse paradigms. This model system will allow us to investigate the impact of Hirano bodies in vivo, the pathways for formation and degradation of Hirano bodies, and whether Hirano bodies promote or modulate development of pathology and disease progression.
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Affiliation(s)
- Sangdeuk Ha
- Department Cellular Biology, University of Georgia, Athens, GA 30602, USA
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Shao CY, Mirra SS, Sait HBR, Sacktor TC, Sigurdsson EM. Postsynaptic degeneration as revealed by PSD-95 reduction occurs after advanced Aβ and tau pathology in transgenic mouse models of Alzheimer's disease. Acta Neuropathol 2011; 122:285-92. [PMID: 21630115 PMCID: PMC3437675 DOI: 10.1007/s00401-011-0843-x] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 04/22/2011] [Accepted: 05/21/2011] [Indexed: 11/27/2022]
Abstract
Impairment of synaptic plasticity underlies memory dysfunction in Alzheimer's disease (AD). Molecules involved in this plasticity such as PSD-95, a major postsynaptic scaffold protein at excitatory synapses, may play an important role in AD pathogenesis. We examined the distribution of PSD-95 in transgenic mice of amyloidopathy (5XFAD) and tauopathy (JNPL3) as well as in AD brains using double-labeling immunofluorescence and confocal microscopy. In wild type control mice, PSD-95 primarily labeled neuropil with distinct distribution in hippocampal apical dendrites. In 3-month-old 5XFAD mice, PSD-95 distribution was similar to that of wild type mice despite significant Aβ deposition. However, in 6-month-old 5XFAD mice, PSD-95 immunoreactivity in apical dendrites markedly decreased and prominent immunoreactivity was noted in neuronal soma in CA1 neurons. Similarly, PSD-95 immunoreactivity disappeared from apical dendrites and accumulated in neuronal soma in 14-month-old, but not in 3-month-old, JNPL3 mice. In AD brains, PSD-95 accumulated in Hirano bodies in hippocampal neurons. Our findings support the notion that either Aβ or tau can induce reduction of PSD-95 in excitatory synapses in hippocampus. Furthermore, this PSD-95 reduction is not an early event but occurs as the pathologies advance. Thus, the time-dependent PSD-95 reduction from synapses and accumulation in neuronal soma in transgenic mice and Hirano bodies in AD may mark postsynaptic degeneration that underlies long-term functional deficits.
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Affiliation(s)
- Charles Y Shao
- Department of Pathology, SUNY Downstate Medical Center, 450 Clarkson Ave., Brooklyn, NY 11203, USA.
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Kato K, Tanaka T, Sadik G, Baba M, Maruyama D, Yanagida K, Kodama T, Morihara T, Tagami S, Okochi M, Kudo T, Takeda M. Protein kinase C stabilizes X-linked inhibitor of apoptosis protein (XIAP) through phosphorylation at Ser(87) to suppress apoptotic cell death. Psychogeriatrics 2011; 11:90-7. [PMID: 21707856 DOI: 10.1111/j.1479-8301.2011.00355.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Multiple protein kinases have been shown to be involved in the apoptotic neuronal loss of Alzheimer's disease (AD). Although some studies support the role of protein kinase C (PKC) in amyloid precursor protein processing as well as in tau phosphorylation, a direct role for PKC in apoptotic neuronal death remains to be clarified. In the present study, we report on the possible role of PKC in cell survival during conditions of stress through phosphorylation of the X-linked inhibitor of apoptosis protein (XIAP). METHODS Phosphorylation of XIAP at Ser87 was confirmed by western blot analysis employing phosphorylation dependent anti-XIAP antibody after incubation of recombinant XIAP with active PKC in vitro. And increased phosphorylation of XIAP at the site was also confirmed in SH-SY5Y cells treated with PKC activator, phorbol 12-myristate 13-acetate (PMA). A mutant XIAP construct in which Ser87 was substituted by Ala, was prepared, and transfected to cells. After the transfection of wild or mutant XIAP, cells viability was evaluated by counting living and dead cells treated with PMA during etoposide-induced apoptosis. RESULTS Recombinant XIAP was phosphorylated at Ser(87) by PKC in vitro and treatment of XIAP-transfected SH-SY5Y cells with a PKC activator, phorbol 12-myristate 13-acetate (PMA) induced phosphorylation of XIAP at Ser(87) . Pulse chase experiments revealed that, when phosphorylated at Ser(87) , wild-type XIAP is more stable than XIAP with a Ser87Ala substitution, which is degraded faster. Importantly, the phosphorylation of XIAP at the site by PKC significantly increased cell survival up to approximately 2.5 times under the condition of apoptosis induced by 25 µg/ml etoposide. CONCLUSION The findings of the present study indicate a role for PKC, through phosphorylation of XIAP at Ser(87) and its stabilization, in cell survival under conditions of stress and lend strength to the idea that PKC is crucial in regulating neuronal homeostasis, which may be impaired in AD.
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Affiliation(s)
- Kiyoko Kato
- Department of Psychiatry, Osaka University Graduate School of Medicine, Osaka, Japan
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Interaction between α-synuclein and tau in Parkinson's disease comment on Wills et al.: elevated tauopathy and α-synuclein pathology in postmortem Parkinson's disease brains with and without dementia. Exp Neurol 2010; 225: 210-218. Exp Neurol 2010; 227:13-8. [PMID: 20965169 DOI: 10.1016/j.expneurol.2010.10.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 10/12/2010] [Indexed: 11/23/2022]
Abstract
Recent neurochemical studies in postmortem brains of patients with Parkinson's disease (PD), PD with dementia (PDD) and age-matched controls revealed significant decrease of tyrosine hydroxylase (TH) and dopamine transporter (DAT) in striatum, confirming previous studies indicating substantial loss of dopaminergic neurons and terminals. Insoluble α-synuclein (αSyn) was significantly increased in both striata and inferior frontal gyrus (IFG), more severe in PDD, probably related to Lewy body (LB) burden discussed as one cause of dementia in PD. Parkin levels frequently related to recessive and young-onset PD were unchanged, suggesting no link to sporadic PD. Novel and most interesting data showed elevated tauopathy in striata of both PD and PDD, associated with increased levels of phosphorylated GSK-3β and reduced 20S proteasomal subunits but - despite increased cortical αSyn - unchanged pTau in IFG, related to increased pGSK-3β and decreased 19S proteasome subunits. These data, recently confirmed in PDGF-αSyn transgenic mice (Haggerty et al., submitted) suggest tauopathy in PD and PDD restricted to the dopaminergic nigrostriatal system and in various animal models of PD show topographic differences from a global tauopathy in Alzheimer's disease (AD) (and other tauopathies). Although some of these data are at variance to current neuropathologic findings in PD and PDD, they confirm frequently discussed correlations/overlaps between AD and PD/PDD and synergistic effects of αSyn, pTau, β-amyloid, and other pathologic proteins, suggesting a dualism or triad of neurodegeneration, the basic molecular pathogenesis remains to be elucidated.
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Abstract
Neurodegenerative diseases are characterized by progressive dysfunction of specific populations of neurons, determining clinical presentation. Neuronal loss is associated with extra and intracellular accumulation of misfolded proteins, the hallmarks of many neurodegenerative proteinopathies. Major basic processes include abnormal protein dynamics due to deficiency of the ubiquitin-proteosome-autophagy system, oxidative stress and free radical formation, mitochondrial dysfunction, impaired bioenergetics, dysfunction of neurotrophins, 'neuroinflammatory' processes and (secondary) disruptions of neuronal Golgi apparatus and axonal transport. These interrelated mechanisms lead to programmed cell death is a long run over many years. Neurodegenerative disorders are classified according to known genetic mechanisms or to major components of protein deposits, but recent studies showed both overlap and intraindividual diversities between different phenotypes. Synergistic mechanisms between pathological proteins suggest common pathogenic mechanisms. Animal models and other studies have provided insight into the basic neurodegeneration and cell death programs, offering new ways for future prevention/treatment strategies.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Kenyongasse, Vienna, Austria.
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Absence of alpha-synuclein pathology in postencephalitic parkinsonism. Acta Neuropathol 2009; 118:371-9. [PMID: 19404653 DOI: 10.1007/s00401-009-0537-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 04/09/2009] [Accepted: 04/10/2009] [Indexed: 01/07/2023]
Abstract
Postencephalitic parkinsonism (PEP), a chronic complication of encephalitis lethargica, is a tauopathy characterized by multisystem neuronal loss and gliosis with widespread neurofibrillary lesions composed of both 3- and 4-repeat (3R and 4R) tau isoforms. Previous immunohistochemical studies in a small number of PEP cases demonstrated absence of Lewy bodies as well as the lack of other alpha-synuclein pathology, classifying PEP as a "pure" tauopathy. Neuropathologic examination of 10 brains with clinico-pathologically verified PEP confirmed widespread neurodegeneration in subcortical and brainstem areas associated with multifocal neurofibrillary pathology comprising both 3R and 4R tau. Very rare beta-amyloid deposits were observed in two elderly patients, while Lewy bodies and neurites or any other alpha-synuclein deposits were completely absent. The causes and molecular background of total absence of alpha-synuclein pathology in PEP, in contrast to most other tauopathies, remain as unknown as the pathogenesis of PEP.
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Jellinger KA. A critical evaluation of current staging of α-synuclein pathology in Lewy body disorders. Biochim Biophys Acta Mol Basis Dis 2009; 1792:730-40. [PMID: 18718530 DOI: 10.1016/j.bbadis.2008.07.006] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 07/23/2008] [Indexed: 12/21/2022]
Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology Kenyongasse 18, Vienna, Austria.
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30
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Jellinger KA. Recent advances in our understanding of neurodegeneration. J Neural Transm (Vienna) 2009; 116:1111-62. [DOI: 10.1007/s00702-009-0240-y] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 05/05/2009] [Indexed: 12/12/2022]
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Tisdale EJ, Azizi F, Artalejo CR. Rab2 utilizes glyceraldehyde-3-phosphate dehydrogenase and protein kinase C{iota} to associate with microtubules and to recruit dynein. J Biol Chem 2009; 284:5876-84. [PMID: 19106097 PMCID: PMC2645835 DOI: 10.1074/jbc.m807756200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 12/01/2008] [Indexed: 01/09/2023] Open
Abstract
Rab2 requires glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and atypical protein kinase Ciota (aPKCiota) for retrograde vesicle formation from vesicular tubular clusters that sort secretory cargo from recycling proteins returned to the endoplasmic reticulum. However, the precise role of GAPDH and aPKCiota in the early secretory pathway is unclear. GAPDH was the first glycolytic enzyme reported to co-purify with microtubules (MTs). Similarly, aPKC associates directly with MTs. To learn whether Rab2 also binds directly to MTs, a MT binding assay was performed. Purified Rab2 was found in a MT-enriched pellet only when both GAPDH and aPKCiota were present, and Rab2-MT binding could be prevented by a recombinant fragment made to the Rab2 amino terminus (residues 2-70), which directly interacts with GAPDH and aPKCiota. Because GAPDH binds to the carboxyl terminus of alpha-tubulin, we characterized the distribution of tyrosinated/detyrosinated alpha-tubulin that is recruited by Rab2 in a quantitative membrane binding assay. Rab2-treated membranes contained predominantly tyrosinated alpha-tubulin; however, aPKCiota was the limiting and essential factor. Tyrosination/detyrosination influences MT motor protein binding; therefore, we determined whether Rab2 stimulated kinesin or dynein membrane binding. Although kinesin was not detected on membranes incubated with Rab2, dynein was recruited in a dose-dependent manner, and binding was aPKCiota-dependent. These combined results suggest a mechanism by which Rab2 controls MT and motor recruitment to vesicular tubular clusters.
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Affiliation(s)
- Ellen J Tisdale
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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Ramesh Babu J, Lamar Seibenhener M, Peng J, Strom AL, Kemppainen R, Cox N, Zhu H, Wooten MC, Diaz-Meco MT, Moscat J, Wooten MW. Genetic inactivation of p62 leads to accumulation of hyperphosphorylated tau and neurodegeneration. J Neurochem 2008; 106:107-20. [PMID: 18346206 DOI: 10.1111/j.1471-4159.2008.05340.x] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The signaling adapter p62 plays a coordinating role in mediating phosphorylation and ubiquitin-dependent trafficking of interacting proteins. However, there is little known about the physiologic role of this protein in brain. Here, we report age-dependent constitutive activation of glycogen synthase kinase 3beta, protein kinase B, mitogen-activated protein kinase, and c-Jun-N-terminal kinase in adult p62(-/-) mice resulting in hyperphosphorylated tau, neurofibrillary tangles, and neurodegeneration. Biochemical fractionation of p62(-/-) brain led to recovery of aggregated K63-ubiquitinated tau. Loss of p62 was manifested by increased anxiety, depression, loss of working memory, and reduced serum brain-derived neurotrophic factor levels. Our findings reveal a novel role for p62 as a chaperone that regulates tau solubility thereby preventing tau aggregation. This study provides a clear demonstration of an Alzheimer-like phenotype in a mouse model in the absence of expression of human genes carrying mutations in amyloid-beta protein precursor, presenilin, or tau. Thus, these findings provide new insight into manifestation of sporadic Alzheimer disease and the impact of obesity.
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Affiliation(s)
- J Ramesh Babu
- Department of Biological Sciences, Program in Cellular and Molecular Biosciences, Auburn University, Auburn, Alabama 36849, USA
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Jellinger KA. A critical reappraisal of current staging of Lewy-related pathology in human brain. Acta Neuropathol 2008; 116:1-16. [PMID: 18592254 DOI: 10.1007/s00401-008-0406-y] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/10/2008] [Accepted: 06/12/2008] [Indexed: 12/21/2022]
Abstract
Sporadic Parkinson disease (sPD) or brainstem-predominant type of Lewy body (LB) disease, and dementia with Lewy bodies (DLB), the two most frequent alpha-synucleinopathies, are progressive multisystem neurodegenerative disorders with widespread occurrence of alpha-synuclein (AS) deposits in the central, peripheral, and autonomic nervous system. For both LB-related disorders, staging/classification systems based on semiquantitative assessment of the distribution and progression pattern of Lewy-related/AS pathology are used that are considered to be linked to clinical dysfunctions. In PD, a six-stage system (Braak) has been suggested to indicate a predictable sequence of lesions with ascending progression from medullary and olfactory nuclei to the cortex, the first two presymptomatic stages being related to incidental LB disease, stages 3 and 4 with motor symptoms, and the last two (cortical) stages may be frequently associated with cognitive impairment. DLB, according to consensus pathologic guidelines, by semiquantitative scoring of AS pathology (LB density and distribution) in specific brain regions, is distinguished into three phenotypes (brainstem, transitional/limbic, and diffuse neocortical), also considering concomitant Alzheimer-related pathology. Retrospective clinico-pathologic studies, although largely confirming the staging system, particularly for younger onset PD with long duration, have shown that between 6.3 and 43% of the cases did not follow the proposed caudo-rostral progression pattern of AS pathology. There was sparing of medullary nuclei in 7-8.3% of clinically manifested PD cases with AS inclusions in midbrain and cortex corresponding to Braak stages 4 and 5, whereas mild parkinsonian symptoms were already observed in stages 2 and 3. There is considerable clinical and pathologic overlap between PD (with or without dementia) and DLB, corresponding to Braak LB stages 5 and 6, both frequently associated with variable Alzheimer-type pathology. Dementia often does not correlate with progressed stages of LB pathology, but may also be related to concomitant Alzheimer lesions or mixed pathologies. There is no relationship between Braak LB stage and the clinical severity of PD, and the predictive validity of this concept is doubtful, since large unselected, retrospective autopsy series in 30-55% of elderly subjects with widespread AS/Lewy-related pathology (Braak stages 5 and 6) reported no definite neuropsychiatric symptoms, suggesting considerable cerebral compensatory mechanisms. Applying the original criteria to large dementia samples, 49% of positive cases were not classifiable. Therefore, modified criteria for the categorization of Lewy-related pathology were proposed for patients with a history of dementia. The causes and molecular basis of the not infrequent deviations from the current staging schemes of AS pathology in PD and DLB, its relation to the onset of classical parkinsonian symptoms and for the lack of definite clinical deficits despite widespread AS pathology in the nervous system remain to be elucidated.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Kenyongasse 18, 1070, Vienna, Austria.
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Jellinger KA, Attems J. Prevalence and impact of vascular and Alzheimer pathologies in Lewy body disease. Acta Neuropathol 2008; 115:427-36. [PMID: 18273624 DOI: 10.1007/s00401-008-0347-5] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 01/21/2008] [Accepted: 01/30/2008] [Indexed: 08/30/2023]
Abstract
Whereas the prevalence and impact of vascular pathology in Alzheimer diease (AD) are well established, the role of vascular and Alzheimer pathologies in the progression of neurodegeneration and cognitive impairment in Parkinson disease (PD) is under discussion. A retrospective clinico-pathologic study of 100 patients with autopsy proven PD (including 44 cases with dementia/PDD) and 20 cases of dementia with Lewy bodies (DLB) confirmed essential clinical (duration of illness, Mini-Mental State Examination/MMSE, age at death) and morphologic differences between these groups; Lewy body Braak scores and Alzheimer pathologies (neuritic Braak stage, cortical Abeta plaque load, and generalized cerebral amyloid angiopathy or CAA) were significantly higher/more severe in DLB and PDD than in PD without dementia. Duration of illness showed no association to any of the examined pathologic parameters, while there was a moderate association between LB scores and neuritic Braak stages, the latter significantly increasing with age. Significant association between cerebrovascular lesions and neuritic Braak stage was seen in PDD but not in PD subjects without dementia. These data suggest an influence of Alzheimer-related lesions on the progression of the neurodegenerative process and, in particular, on cognitive decline in both PDD and DLB. On the other hand, both these factors in PD and DLB appear to be largely independent from coexistent vascular pathology, except in cases with severe cerebrovascular lesions or those related to neuritic AD pathology. Assessment of ApoE genotype in a small number of cases showed no significant differences in the severity of Abeta plaque load and CAA except for much lower intensities in non-demented epsilon3/3 patients. Despite increasing evidence suggesting synergistic reactions between alpha-synuclein (alphaSyn), tau and Abeta-peptides, the major protein markers of both AD and Lewy body diseases, and of both vascular pathology and AD, the molecular background and pathophysiological impact of these pathologies on the progression of neurodegeneration and development of cognitive decline in PD await further elucidation.
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Davis RC, Furukawa R, Fechheimer M. A cell culture model for investigation of Hirano bodies. Acta Neuropathol 2008; 115:205-17. [PMID: 17978823 DOI: 10.1007/s00401-007-0275-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 07/24/2007] [Accepted: 07/26/2007] [Indexed: 11/28/2022]
Abstract
Hirano bodies are paracrystalline F-actin-rich aggregations associated with a variety of conditions including aging, and neurodegenerative diseases. The composition and structure of these inclusions have been described by immunohistochemistry and ultrastructure, respectively. However, studies of the physiological function and dynamics of Hirano bodies have been hindered due to lack of a facile in vitro experimental system. We have developed a model for formation of Hirano bodies in mammalian cell cultures by expression of the carboxy-terminal fragment (CT) of a 34-kDa actin-bundling protein. Expression of the CT protein induces F-actin rearrangement in HEK 293, HeLa, Cos7 cells, neuroblastoma and astrocytic cells, and in primary neurons. We have termed these structures model Hirano bodies, since their composition and ultrastructure is quite similar to that reported in vivo. Model Hirano bodies in cell cultures sometimes appeared to be formed of a number of smaller domains, suggesting that small aggregates are intermediates in the formation of Hirano bodies. Stable lines expressing CT and bearing model Hirano bodies exhibit normal growth, morphology, and motility. This model provides a valuable system for the study of the dynamics of Hirano bodies, and their role in disease processes.
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Affiliation(s)
- Richard C Davis
- Department of Cellular Biology, University of Georgia, 724 Biological Sciences, Athens, GA 30602, USA
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Jellinger KA. Morphological substrates of parkinsonism with and without dementia: a retrospective clinico-pathological study. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2007:91-104. [PMID: 17982882 DOI: 10.1007/978-3-211-73574-9_12] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A retrospective study of a 50-year autopsy series of 900 patients with the clinical diagnosis of parkinsonism (31.2% with dementia) revealed pure Lewy body disease (LBD) in 84.9%, but only 44.7% with idiopathic Parkinson disease (PD); 16% were associated with cerebrovascular lesions, 14.8% with Alzheimer pathology; 8.9% were classified dementia with Lewy bodies (DLB), 9.4% showed other degenerative disorders, and 5.6% other/ secondary parkinsonian syndromes. The frequency of LBD during different periods was fairly stable, with increase of DLB and PD plus Alzheimer changes, but decrease of associated cerebrovascular lesions during the last decades. Using variable clinical diagnostic criteria not only by specified neurologists, the misdiagnosis rate ranged from 11.5 to 23% and was similar to that in most previous clinico-pathological studies. The majority of cases with false clinical diagnosis of PD had a final pathological diagnosis of DLB with or without Alzheimer lesions. A postmortem series of 330 elderly patients clinically diagnosed as parkinsonism with (37.6%) and without dementia showed that IPD, Braak stages 3-5 were rarely associated with cognitive impairment, which was frequently seen in IPD with associated Alzheimer pathology (35.5%), DLB (33.9%), and in Alzheimer disease (AD) or mixed dementia (17%), whereas it almost never was associated with minor cerebrovascular lesions. Clinico-pathological studies in DBL, demented and nondemented PD, and AD cases showed a negative relation between cognitive impairment and Alzheimer changes, suggesting that these either alone or in combination with cortical Lewy body pathologies are major causes of cognitive dysfunction. Further prospective clinico-pathological studies are needed to validate the currently used clinical criteria for PD, to increase the diagnostic accuracy until effective biomarkers are available, and to clarify the impact of structural and functional changes on cognitive function in parkinsonism as an ultimate goal of early disease detection and effective treatment.
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Affiliation(s)
- K A Jellinger
- Institute of Clinical Neurobiology, Vienna, Austria.
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