1
|
Czuczwar SJ, Kocki J, Miziak B, Bogucki J, Bogucka-Kocka A, Pluta R. Alpha-, Beta-, and Gamma-Secretase, Amyloid Precursor Protein, and Tau Protein Genes in the Hippocampal CA3 Subfield in an Ischemic Model of Alzheimer's Disease with Survival up to 2 Years. J Alzheimers Dis 2024; 98:151-161. [PMID: 38393914 DOI: 10.3233/jad-231333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Background Understanding the phenomena underlying the non-selective susceptibility to ischemia of pyramidal neurons in the CA3 is important from the point of view of elucidating the mechanisms of memory loss and the development of dementia. Objective The aim of the study was to investigate changes in genes expression of amyloid precursor protein, its cleaving enzymes and tau protein in CA3 post-ischemia with survival of 12-24 months. Methods We used an ischemic model of Alzheimer's disease to study the above genes using an RT-PCR protocol. Results The expression of the amyloid precursor protein gene was above the control values at all times post-ischemia. The expression of the α-secretase gene also exceeded the control values post-ischemia. The expression of the β-secretase gene increased 12 and 24 months post-ischemia, and 18 months was below control values. Presenilin 1 and 2 genes expression was significantly elevated at all times post-ischemia. Also, tau protein gene expression was significantly elevated throughout the observation period, and peak gene expression was present 12 months post-ischemia. Conclusions The study suggests that the genes studied are involved in the non-amyloidogenic processing of amyloid precursor protein. Additionally data indicate that brain ischemia with long-term survival causes damage and death of pyramidal neurons in the CA3 area of the hippocampus in a modified tau protein-dependent manner. Thus defining a new and important mechanism of pyramidal neuronal death in the CA3 area post-ischemia. In addition expression of tau protein gene modification after brain ischemia is useful in identifying ischemic mechanisms occurring in Alzheimer's disease.
Collapse
Affiliation(s)
| | - Janusz Kocki
- Department of Clinical Genetics, Medical University of Lublin, Lublin, Poland
| | - Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Jacek Bogucki
- Department of Organic Chemistry, Faculty of Pharmacy, Medical University of Lublin, Lublin, Poland
| | - Anna Bogucka-Kocka
- Department of Biology and Genetics, Medical University of Lublin, Lublin, Poland
| | - Ryszard Pluta
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| |
Collapse
|
2
|
Pluta R, Januszewski S, Jabłoński M. Acetylated Tau Protein: A New Piece in the Puzzle between Brain Ischemia and Alzheimer’s Disease. Int J Mol Sci 2022; 23:ijms23169174. [PMID: 36012440 PMCID: PMC9408862 DOI: 10.3390/ijms23169174] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Correspondence: ; Tel.: +48-22-6086-540
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Mirosław Jabłoński
- Department of Rehabilitation and Orthopedics, Medical University of Lublin, 20-090 Lublin, Poland
| |
Collapse
|
3
|
Post-Ischemic Neurodegeneration of the Hippocampus Resembling Alzheimer's Disease Proteinopathy. Int J Mol Sci 2021; 23:ijms23010306. [PMID: 35008731 PMCID: PMC8745293 DOI: 10.3390/ijms23010306] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 12/26/2021] [Accepted: 12/26/2021] [Indexed: 12/14/2022] Open
Abstract
In this review, we summarize, inter alia, the protein and gene changes associated with Alzheimer’s disease and their role in post-ischemic hippocampal neurodegeneration. In the hippocampus, studies have revealed dysregulation of the genes for the amyloid protein precursor metabolism and tau protein that is identical in nature to Alzheimer’s disease. Data indicate that amyloid and tau protein, derived from brain tissue and blood due to increased permeability of the blood–brain barrier after ischemia, play a key role in post-ischemic neurodegeneration of the hippocampus, with concomitant development of full-blown dementia. Thus, the knowledge of new neurodegenerative mechanisms that cause neurodegeneration of the hippocampus after ischemia, resembling Alzheimer’s disease proteinopathy, will provide the most important therapeutic development goals to date.
Collapse
|
4
|
Pluta R, Czuczwar SJ, Januszewski S, Jabłoński M. The Many Faces of Post-Ischemic Tau Protein in Brain Neurodegeneration of the Alzheimer's Disease Type. Cells 2021; 10:cells10092213. [PMID: 34571862 PMCID: PMC8465797 DOI: 10.3390/cells10092213] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022] Open
Abstract
Recent data suggest that post-ischemic brain neurodegeneration in humans and animals is associated with the modified tau protein in a manner typical of Alzheimer’s disease neuropathology. Pathological changes in the tau protein, at the gene and protein level due to cerebral ischemia, can lead to the development of Alzheimer’s disease-type neuropathology and dementia. Some studies have shown increased tau protein staining and gene expression in neurons following ischemia-reperfusion brain injury. Recent studies have found the tau protein to be associated with oxidative stress, apoptosis, autophagy, excitotoxicity, neuroinflammation, blood-brain barrier permeability, mitochondrial dysfunction, and impaired neuronal function. In this review, we discuss the interrelationship of these phenomena with post-ischemic changes in the tau protein in the brain. The tau protein may be at the intersection of many pathological mechanisms due to severe neuropathological changes in the brain following ischemia. The data indicate that an episode of cerebral ischemia activates the damage and death of neurons in the hippocampus in a tau protein-dependent manner, thus determining a novel and important mechanism for the survival and/or death of neuronal cells following ischemia. In this review, we update our understanding of proteomic and genomic changes in the tau protein in post-ischemic brain injury and present the relationship between the modified tau protein and post-ischemic neuropathology and present a positive correlation between the modified tau protein and a post-ischemic neuropathology that has characteristics of Alzheimer’s disease-type neurodegeneration.
Collapse
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Str. Pawińskiego, 02-106 Warsaw, Poland;
- Correspondence: ; Tel.: +48-22-6086-540
| | - Stanisław J. Czuczwar
- Department of Pathophysiology, Medical University of Lublin, 8b Str. Jaczewskiego, 20-090 Lublin, Poland;
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Str. Pawińskiego, 02-106 Warsaw, Poland;
| | - Mirosław Jabłoński
- Department of Rehabilitation and Orthopedics, Medical University of Lublin, 8 Str. Jaczewskiego, 20-090 Lublin, Poland;
| |
Collapse
|
5
|
Participation of Amyloid and Tau Protein in Post-Ischemic Neurodegeneration of the Hippocampus of a Nature Identical to Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22052460. [PMID: 33671097 PMCID: PMC7957532 DOI: 10.3390/ijms22052460] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 02/05/2023] Open
Abstract
Recent evidence suggests that amyloid and tau protein are of vital importance in post-ischemic death of CA1 pyramidal neurons of the hippocampus. In this review, we summarize protein alterations associated with Alzheimer's disease and their gene expression (amyloid protein precursor and tau protein) after cerebral ischemia, as well as their roles in post-ischemic hippocampus neurodegeneration. In recent years, multiple studies aimed to elucidate the post-ischemic processes in the development of hippocampus neurodegeneration. Their findings have revealed the dysregulation of genes for amyloid protein precursor, β-secretase, presenilin 1 and 2, tau protein, autophagy, mitophagy, and apoptosis identical in nature to Alzheimer's disease. Herein, we present the latest data showing that amyloid and tau protein associated with Alzheimer's disease and their genes play a key role in post-ischemic neurodegeneration of the hippocampus with subsequent development of dementia. Therefore, understanding the underlying process for the development of post-ischemic CA1 area neurodegeneration in the hippocampus in conjunction with Alzheimer's disease-related proteins and genes will provide the most important therapeutic development goals to date.
Collapse
|
6
|
Pluta R, Januszewski S, Czuczwar SJ. Brain Ischemia as a Prelude to Alzheimer's Disease. Front Aging Neurosci 2021; 13:636653. [PMID: 33679381 PMCID: PMC7931451 DOI: 10.3389/fnagi.2021.636653] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/25/2021] [Indexed: 01/07/2023] Open
Abstract
Transient ischemic brain injury causes massive neuronal death in the hippocampus of both humans and animals. This was accompanied by progressive atrophy of the hippocampus, brain cortex, and white matter lesions. Furthermore, it has been noted that neurodegenerative processes after an episode of ischemia-reperfusion in the brain can continue well-beyond the acute stage. Rarefaction of white matter was significantly increased in animals at 2 years following ischemia. Some rats that survived 2 years after ischemia developed severe brain atrophy with dementia. The profile of post-ischemic brain neurodegeneration shares a commonality with neurodegeneration in Alzheimer's disease. Furthermore, post-ischemic brain injury is associated with the deposition of folding proteins, such as amyloid and tau protein, in the intracellular and extracellular space. Recent studies on post-ischemic brain neurodegeneration have revealed the dysregulation of Alzheimer's disease-associated genes such as amyloid protein precursor, α-secretase, β-secretase, presenilin 1, presenilin 2, and tau protein. The latest data demonstrate that Alzheimer's disease-related proteins and their genes play a key role in the development of post-ischemic brain neurodegeneration with full-blown dementia in disease types such as Alzheimer's. Ongoing interest in the study of brain ischemia has provided evidence showing that ischemia may be involved in the development of the genotype and phenotype of Alzheimer's disease, suggesting that brain ischemia can be considered as a useful model for understanding the mechanisms responsible for the initiation of Alzheimer's disease.
Collapse
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland,*Correspondence: Ryszard Pluta
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | | |
Collapse
|
7
|
Pluta R, Ułamek-Kozioł M, Januszewski S, Czuczwar SJ. Shared Genomic and Proteomic Contribution of Amyloid and Tau Protein Characteristic of Alzheimer's Disease to Brain Ischemia. Int J Mol Sci 2020; 21:ijms21093186. [PMID: 32366028 PMCID: PMC7246538 DOI: 10.3390/ijms21093186] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 01/07/2023] Open
Abstract
Post-ischemic brain damage is associated with the deposition of folding proteins such as the amyloid and tau protein in the intra- and extracellular spaces of brain tissue. In this review, we summarize the protein changes associated with Alzheimer's disease and their gene expression (amyloid protein precursor and tau protein) after ischemia-reperfusion brain injury and their role in the post-ischemic injury. Recent advances in understanding the post-ischemic neuropathology have revealed dysregulation of amyloid protein precursor, α-secretase, β-secretase, presenilin 1 and 2, and tau protein genes after ischemic brain injury. However, reduced expression of the α-secretase in post-ischemic brain causes neurons to be less resistant to injury. In this review, we present the latest evidence that proteins associated with Alzheimer's disease and their genes play a key role in progressive brain damage due to ischemia and reperfusion, and that an ischemic episode is an essential and leading supplier of proteins and genes associated with Alzheimer's disease in post-ischemic brain. Understanding the underlying processes of linking Alzheimer's disease-related proteins and their genes in post-ischemic brain injury with the risk of developing Alzheimer's disease will provide the most significant goals for therapeutic development to date.
Collapse
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.U.-K.); (S.J.)
- Correspondence:
| | - Marzena Ułamek-Kozioł
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.U.-K.); (S.J.)
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.U.-K.); (S.J.)
| | | |
Collapse
|
8
|
Proteomic and Genomic Changes in Tau Protein, Which Are Associated with Alzheimer's Disease after Ischemia-Reperfusion Brain Injury. Int J Mol Sci 2020; 21:ijms21030892. [PMID: 32019137 PMCID: PMC7037789 DOI: 10.3390/ijms21030892] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 01/12/2023] Open
Abstract
Recent evidence suggests that transient ischemia of the brain with reperfusion in humans and animals is associated with the neuronal accumulation of neurotoxic molecules associated with Alzheimer’s disease, such as all parts of the amyloid protein precursor and modified tau protein. Pathological changes in the amyloid protein precursor and tau protein at the protein and gene level due to ischemia may lead to dementia of the Alzheimer’s disease type after ischemic brain injury. Some studies have demonstrated increased tau protein immunoreactivity in neuronal cells after brain ischemia-reperfusion injury. Recent research has presented many new tau protein functions, such as neural activity control, iron export, protection of genomic DNA integrity, neurogenesis and long-term depression. This review discusses the potential mechanisms of tau protein in the brain after ischemia, including oxidative stress, apoptosis, autophagy, excitotoxicity, neurological inflammation, endothelium, angiogenesis and mitochondrial dysfunction. In addition, attention was paid to the role of tau protein in damage to the neurovascular unit. Tau protein may be at the intersection of many regulatory mechanisms in the event of major neuropathological changes in ischemic stroke. Data show that brain ischemia activates neuronal changes and death in the hippocampus in a manner dependent on tau protein, thus determining a new and important way to regulate the survival and/or death of post-ischemic neurons. Meanwhile, the association between tau protein and ischemic stroke has not been well discussed. In this review, we aim to update the knowledge about the proteomic and genomic changes in tau protein following ischemia-reperfusion injury and the connection between dysfunctional tau protein and ischemic stroke pathology. Finally we present the positive correlation between tau protein dysfunction and the development of sporadic Alzheimer’s disease type of neurodegeneration.
Collapse
|
9
|
Ułamek-Kozioł M, Czuczwar SJ, Januszewski S, Pluta R. Substantiation for the Use of Curcumin during the Development of Neurodegeneration after Brain Ischemia. Int J Mol Sci 2020; 21:ijms21020517. [PMID: 31947633 PMCID: PMC7014172 DOI: 10.3390/ijms21020517] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 01/21/2023] Open
Abstract
Currently available pharmacological treatment of post-ischemia-reperfusion brain injury has limited effectiveness. This review provides an assessment of the current state of neurodegeneration treatment due to ischemia-reperfusion brain injury and focuses on the role of curcumin in the diet. The purpose of this review was to provide a comprehensive overview of what was published about the benefits of curcumin influence on post-ischemic brain damage. Some data on the clinical benefits of curcumin treatment of post-ischemic brain in terms of clinical symptoms and adverse reactions have been reviewed. The data in this review contributes to a better understanding of the potential benefits of curcumin in the treatment of neurodegenerative changes after ischemia and informs scientists, clinicians, and patients, as well as their families and caregivers about the possibilities of such treatment. Due to the pleotropic properties of curcumin, including anti-amyloid, anti-tau protein hyperphosphorylation, anti-inflammatory, anti-apoptotic, and neuroprotective action, as well as increasing neuronal lifespan and promoting neurogenesis, curcumin is a promising candidate for the treatment of post-ischemic neurodegeneration with misfolded proteins accumulation. In this way, it may gain interest as a potential therapy to prevent the development of neurodegenerative changes after cerebral ischemia. In addition, it is a safe substance and inexpensive, easily accessible, and can effectively penetrate the blood–brain barrier and neuronal membranes. In conclusion, the evidence available in a review of the literature on the therapeutic potential of curcumin provides helpful insight into the potential clinical utility of curcumin in the treatment of neurological neurodegenerative diseases with misfolded proteins. Therefore, curcumin may be a promising supplementary agent against development of neurodegeneration after brain ischemia in the future. Indeed, there is a rational scientific basis for the use of curcumin for the prophylaxis and treatment of post-ischemic neurodegeneration.
Collapse
Affiliation(s)
- Marzena Ułamek-Kozioł
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.U.-K.)
- First Department of Neurology, Institute of Psychiatry and Neurology, 02-957 Warsaw, Poland
| | | | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.U.-K.)
| | - Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland; (M.U.-K.)
- Correspondence: ; Tel.: +48-22-6086-540/6086-469
| |
Collapse
|
10
|
Chen X, Jiang H. Tau as a potential therapeutic target for ischemic stroke. Aging (Albany NY) 2019; 11:12827-12843. [PMID: 31841442 PMCID: PMC6949092 DOI: 10.18632/aging.102547] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 11/19/2019] [Indexed: 12/12/2022]
Abstract
Tau is a protein mainly expressed in adult human brain. It plays important roles both in neurodegenerative diseases and stroke. Stroke is an important cause of adult death and disability, ischemic stroke almost account for 80% in all cases. Abundant studies have proven that the increase of dysfunctional tau may act as a vital factor in pathological changes after ischemic stroke. However, the relationship between tau and ischemic stroke remains ununified. Based on present studies, we firstly introduced the structure and biological function of tau protein. Secondly, we summarized the potential regulatory mechanisms of tau protein in the process of ischemic stroke. Thirdly, we discussed about the findings in therapeutic researches of ischemic stroke. This review may be helpful in implementing new therapies for ischemic stroke and may be beneficial for the clinical and experimental studies.
Collapse
Affiliation(s)
- Xin Chen
- Department of Geriatrics, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hua Jiang
- Department of Geriatrics, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| |
Collapse
|
11
|
Pluta R, Ułamek-Kozioł M, Januszewski S, Czuczwar SJ. Tau Protein Dysfunction after Brain Ischemia. J Alzheimers Dis 2019; 66:429-437. [PMID: 30282370 PMCID: PMC6218135 DOI: 10.3233/jad-180772] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Brain ischemia comprises blood-brain barrier, glial, and neuronal cells. The blood–brain barrier controls permeability of different substances and the composition of the neuronal cells ‘milieu’, which is required for their physiological functioning. Recent evidence indicates that brain ischemia itself and ischemic blood-brain barrier dysfunction is associated with the accumulation of neurotoxic molecules within brain tissue, e.g., different parts of amyloid-β protein precursor and changed pathologically tau protein. All these changes due to ischemia can initiate and progress neurodegeneration of the Alzheimer’s disease-type. This review presents brain ischemia and ischemic blood-brain barrier as a trigger for tau protein alterations. Thus, we hypothesize that the changes in pattern of phosphorylation of tau protein are critical to microtubule function especially in neurons, and contribute to the neurodegeneration following brain ischemia-reperfusion episodes with Alzheimer’s disease phenotype.
Collapse
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Marzena Ułamek-Kozioł
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.,First Department of Neurology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | | |
Collapse
|
12
|
Tau exacerbates excitotoxic brain damage in an animal model of stroke. Nat Commun 2017; 8:473. [PMID: 28883427 PMCID: PMC5589746 DOI: 10.1038/s41467-017-00618-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/13/2017] [Indexed: 02/07/2023] Open
Abstract
Neuronal excitotoxicity induced by aberrant excitation of glutamatergic receptors contributes to brain damage in stroke. Here we show that tau-deficient (tau−/−) mice are profoundly protected from excitotoxic brain damage and neurological deficits following experimental stroke, using a middle cerebral artery occlusion with reperfusion model. Mechanistically, we show that this protection is due to site-specific inhibition of glutamate-induced and Ras/ERK-mediated toxicity by accumulation of Ras-inhibiting SynGAP1, which resides in a post-synaptic complex with tau. Accordingly, reducing SynGAP1 levels in tau−/− mice abolished the protection from pharmacologically induced excitotoxicity and middle cerebral artery occlusion-induced brain damage. Conversely, over-expression of SynGAP1 prevented excitotoxic ERK activation in wild-type neurons. Our findings suggest that tau mediates excitotoxic Ras/ERK signaling by controlling post-synaptic compartmentalization of SynGAP1. Excitotoxicity contributes to neuronal injury following stroke. Here the authors show that tau promotes excitotoxicity by a post-synaptic mechanism, involving site-specific control of ERK activation, in a mouse model of stroke.
Collapse
|
13
|
Cardona-Gómez GP, Lopera F. Dementia, Preclinical Studies in Neurodegeneration and its Potential for Translational Medicine in South America. Front Aging Neurosci 2016; 8:304. [PMID: 28066230 PMCID: PMC5167748 DOI: 10.3389/fnagi.2016.00304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 11/29/2016] [Indexed: 12/17/2022] Open
Abstract
Latin-American people with dementia will increase to an astounding 368% in 2050, higher than USA and Europe. In addition, to sporadic dementia type like Alzheimer, and vascular dementia (VaD) progression after Cerebrovascular disease is also found. These incidences are increased in Colombia by specific populations affected with pure Neurodegenerative and VaDs like Autosomical Dominant familial Alzheimer’s disease (AD) and Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). In spite of the enormous human effort with and economical effort and investment costs, neither sporadic nor genetic kinds of dementia progression have been prevented or blocked yet. Currently, there exist several animal models that partially solve the understanding of the neurodegenerative etiopathogenesis and its treatment. However, when the potential therapies are translated to humans, those do not work or present a limited action. Main difficulties are the diverse comorbility associated to the cause and/or several affected brain regions, reducing the efficacy of some therapies which are limited to a tissue-specific action or modulating a kind of neurotransmission. Global investigation suggests that a general prevention could be achieved with the improvement in the quality of lifestyle, including healthy diet, physical and mental activity, and avoiding mechanical or chemical pro-inflammatory events in an early stage in the most of non-communicable diseases. In this review article, we present some molecular targets and preclinical studies in animal models to propose strategies that could be useful in a future translation to prevent or block neurodegeneration: one is gene therapy; silencing pathogenic genes in critical brain areas where excitotoxicity arise and spread. Another is to take advantage of the natural source and its wide biodiversity of natural products that are capable of identifying, by the blocking and prevention of neurodegeneration. On the other side, the casuistic of pure dementias in the Latin-American region gives an exceptional opportunity to understand the pathogenesis in these human populations. Further, this is in support of the basic and clinical researchers working on an interaction for a better understanding and medical care of mixed dementias, which have more complex factors than pure ones. However, to promote the translation of any therapeutical alternative is necessary to clarify the normative and the protocols for developing clinical trials with original candidates or work upon strategies proposed from South-American countries.
Collapse
Affiliation(s)
- Gloria Patricia Cardona-Gómez
- Cellular and Molecular Neurobiology Area, Neuroscience Group of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia Medellin, Colombia
| | - Francisco Lopera
- Clinical Neuroscience Area, Neuroscience Group of Antioquia, Faculty of Medicine, Sede de Investigación Universitaria (SIU), University of Antioquia Medellin, Colombia
| |
Collapse
|
14
|
Majd S, Power JHT, Koblar SA, Grantham HJM. Early glycogen synthase kinase-3β and protein phosphatase 2A independent tau dephosphorylation during global brain ischaemia and reperfusion following cardiac arrest and the role of the adenosine monophosphate kinase pathway. Eur J Neurosci 2016; 44:1987-97. [PMID: 27177932 PMCID: PMC5089632 DOI: 10.1111/ejn.13277] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 12/13/2022]
Abstract
Abnormal tau phosphorylation (p‐tau) has been shown after hypoxic damage to the brain associated with traumatic brain injury and stroke. As the level of p‐tau is controlled by Glycogen Synthase Kinase (GSK)‐3β, Protein Phosphatase 2A (PP2A) and Adenosine Monophosphate Kinase (AMPK), different activity levels of these enzymes could be involved in tau phosphorylation following ischaemia. This study assessed the effects of global brain ischaemia/reperfusion on the immediate status of p‐tau in a rat model of cardiac arrest (CA) followed by cardiopulmonary resuscitation (CPR). We reported an early dephosphorylation of tau at its AMPK sensitive residues, Ser396 and Ser262after 2 min of ischaemia, which did not recover during the first two hours of reperfusion, while the tau phosphorylation at GSK‐3β sensitive but AMPK insensitive residues, Ser202/Thr205 (AT8), as well as the total amount of tau remained unchanged. Our data showed no alteration in the activities of GSK‐3β and PP2A during similar episodes of ischaemia of up to 8 min and reperfusion of up to 2 h, and 4 weeks recovery. Dephosphorylation of AMPK followed the same pattern as tau dephosphorylation during ischaemia/reperfusion. Catalase, another AMPK downstream substrate also showed a similar pattern of decline to p‐AMPK, in ischaemic/reperfusion groups. This suggests the involvement of AMPK in changing the p‐tau levels, indicating that tau dephosphorylation following ischaemia is not dependent on GSK‐3β or PP2A activity, but is associated with AMPK dephosphorylation. We propose that a reduction in AMPK activity is a possible early mechanism responsible for tau dephosphorylation.
Collapse
Affiliation(s)
- Shohreh Majd
- Centre for Neuroscience, Neuronal Injury and Repair Laboratory, School of Medicine, Flinders University of South Australia, Adelaide, SA, 5042, Australia
| | - John H T Power
- Department of Human Physiology, School of Medicine, Flinders University of South Australia, Adelaide, SA, Australia
| | - Simon A Koblar
- School of Medicine, The Queen Elizabeth Hospital (TQEH) Campus, University of Adelaide, Adelaide, SA, Australia
| | - Hugh J M Grantham
- Centre for Neuroscience, Neuronal Injury and Repair Laboratory, School of Medicine, Flinders University of South Australia, Adelaide, SA, 5042, Australia
| |
Collapse
|
15
|
Michalski D, Preißler H, Hofmann S, Kacza J, Härtig W. Decline of microtubule-associated protein tau after experimental stroke in differently aged wild-type and 3xTg mice with Alzheimer-like alterations. Neuroscience 2016; 330:1-11. [PMID: 27189884 DOI: 10.1016/j.neuroscience.2016.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 01/25/2023]
Abstract
Stroke therapies are still limited to a minority of patients. Considering time-dependent aspects of stroke, the penumbra concept describes the transition from functional to permanent tissue damage. Thereby, the role of cytoskeletal elements, as for instance microtubules with associated tau remains poorly understood and is therefore not yet considered for therapeutic approaches. This study explored the expression of microtubule-associated protein tau related to neuronal damage in stroke-affected brain regions. Wild-type and triple-transgenic mice of 3, 7 and 12months of age and with an Alzheimer-like background underwent experimental stroke. After 24h, brain sections were used for immunofluorescence labeling of tau and Neuronal Nuclei (NeuN). Potential functional consequences of cellular alterations were explored by statistical relationships to the general health condition, i.e. neurobehavioral deficits and loss of body weight. Immunoreactivity for whole tau decreased significantly in ischemic areas, while the decline at the border zone was more drastic for tau-immunoreactivity compared with the diminished NeuN labeling. Quantitative analyses confirmed pronounced sensitivity for tau-immunoreactivity in the ischemic border zone. Decline of tau- as well as NeuN-immunoreactivity correlated with body weight loss during the 24-h observation period. In conclusion, microtubule-associated protein tau was robustly identified as a highly sensitive cytoskeletal constitute under ischemic conditions, suggesting a pivotal role during the transition process toward long-lasting tissue damage. Consequently, cytoskeletal elements appear as promising targets for novel therapeutic approaches with the objective to impede ischemia-induced irreversible cellular degradation.
Collapse
Affiliation(s)
- Dominik Michalski
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
| | - Hartmut Preißler
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany
| | - Sarah Hofmann
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany
| | - Johannes Kacza
- Institute of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 43, 04103 Leipzig, Germany
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany
| |
Collapse
|
16
|
Ułamek-Kozioł M, Pluta R, Bogucka-Kocka A, Januszewski S, Kocki J, Czuczwar SJ. Brain ischemia with Alzheimer phenotype dysregulates Alzheimer's disease-related proteins. Pharmacol Rep 2016; 68:582-91. [PMID: 26940197 DOI: 10.1016/j.pharep.2016.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 02/04/2023]
Abstract
There are evidences for the influence of Alzheimer's proteins on postischemic brain injury. We present here an overview of the published evidence underpinning the relationships between β-amyloid peptide, hyperphosphorylated tau protein, presenilins, apolipoproteins, secretases and neuronal survival/death decisions after ischemia and development of postischemic dementia. The interactions of above molecules and their influence and contribution to final ischemic brain degeneration resulting in dementia of Alzheimer phenotype are reviewed. Generation and deposition of β-amyloid peptide and tau protein pathology are essential factors involved in Alzheimer's disease development as well as in postischemic brain dementia. Postischemic injuries demonstrate that ischemia may stimulate pathological amyloid precursor protein processing by upregulation of β- and γ-secretases and therefore are capable of establishing a vicious cycle. Functional postischemic brain recovery is always delayed and incomplete by an injury-related increase in the amount of the neurotoxic C-terminal of amyloid precursor protein and β-amyloid peptide. Finally, we present here the concept that Alzheimer's proteins can contribute to and/or precipitate postischemic brain neurodegeneration including dementia with Alzheimer's phenotype.
Collapse
Affiliation(s)
- Marzena Ułamek-Kozioł
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warszawa, Poland
| | - Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warszawa, Poland.
| | - Anna Bogucka-Kocka
- Department of Pharmaceutical Botany, Medical University of Lublin, Lublin, Poland
| | - Sławomir Januszewski
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warszawa, Poland
| | - Janusz Kocki
- Department of Clinical Genetics, Medical University of Lublin, Lublin, Poland
| | | |
Collapse
|
17
|
Zhang CE, Yang X, Li L, Sui X, Tian Q, Wei W, Wang J, Liu G. Hypoxia-induced tau phosphorylation and memory deficit in rats. NEURODEGENER DIS 2014; 14:107-16. [PMID: 24993525 DOI: 10.1159/000362239] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 03/17/2014] [Indexed: 11/19/2022] Open
Abstract
Hypoxia was shown to be associated with an increased risk of Alzheimer's disease (AD). The effects of hypoxia on the development of AD pathology and spatial memory ability and the possible molecular mechanisms remain poorly understood. In this study, we demonstrate that rats exposed to a hypoxic condition (10% oxygen concentration) for 1, 2, 4 and 8 weeks (6 h each day) displayed spatial memory impairment and increased tau phosphorylation at Ser198/199/202, Thr205, Ser262, Ser396 and Ser404 in the hippocampus. Concomitantly, the levels of Tyr216-phosphorylated glycogen synthase kinase (GSK)-3β (activated form of GSK-3β) and Tyr307-phosphorylated protein phosphatase 2A (inactivated form of PP2A) were significantly increased in the hippocampus of the rats with 1, 2, 4 and 8 weeks of hypoxia exposure, while the levels of methylated PP2A (activated form of PP2A) were significantly decreased in the hippocampus of the rats with 4 and 8 weeks of hypoxia exposure. In addition, the content of malondialdehyde, an indicator of oxidative stress, was elevated, whereas the activity of superoxide dismutase was not significantly changed in the hippocampus of the rats exposed to hypoxia. Taken together, these data demonstrated that hypoxia induced tau hyperphosphorylation and memory impairment in rats, and that the increased tau phosphorylation could be attributed to activation of GSK-3β and inactivation of PP2A. These data suggest that interventions to improve hypoxia may be helpful to prevent the development of AD pathology and cognitive impairment.
Collapse
Affiliation(s)
- Chang-E Zhang
- Department of Pathophysiology, Guangzhou Medical University, Guangzhou, China
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Pluta R, Jabłoński M, Ułamek-Kozioł M, Kocki J, Brzozowska J, Januszewski S, Furmaga-Jabłońska W, Bogucka-Kocka A, Maciejewski R, Czuczwar SJ. Sporadic Alzheimer's disease begins as episodes of brain ischemia and ischemically dysregulated Alzheimer's disease genes. Mol Neurobiol 2013; 48:500-15. [PMID: 23519520 PMCID: PMC3825141 DOI: 10.1007/s12035-013-8439-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/05/2013] [Indexed: 12/22/2022]
Abstract
The study of sporadic Alzheimer’s disease etiology, now more than ever, needs an infusion of new concepts. Despite ongoing interest in Alzheimer’s disease, the basis of this entity is not yet clear. At present, the best-established and accepted “culprit” in Alzheimer’s disease pathology by most scientists is the amyloid, as the main molecular factor responsible for neurodegeneration in this disease. Abnormal upregulation of amyloid production or a disturbed clearance mechanism may lead to pathological accumulation of amyloid in brain according to the “amyloid hypothesis.” We will critically review these observations and highlight inconsistencies between the predictions of the “amyloid hypothesis” and the published data. There is still controversy over the role of amyloid in the pathological process. A question arises whether amyloid is responsible for the neurodegeneration or if it accumulates because of the neurodegeneration. Recent evidence suggests that the pathophysiology and neuropathology of Alzheimer’s disease comprises more than amyloid accumulation, tau protein pathology and finally brain atrophy with dementia. Nowadays, a handful of researchers share a newly emerged view that the ischemic episodes of brain best describe the pathogenic cascade, which eventually leads to neuronal loss, especially in hippocampus, with amyloid accumulation, tau protein pathology and irreversible dementia of Alzheimer type. The most persuasive evidences come from investigations of ischemically damaged brains of patients and from experimental ischemic brain studies that mimic Alzheimer-type dementia. This review attempts to depict what we know and do not know about the triggering factor of the Alzheimer’s disease, focusing on the possibility that the initial pathological trigger involves ischemic episodes and ischemia-induced gene dysregulation. The resulting brain ischemia dysregulates additionally expression of amyloid precursor protein and amyloid-processing enzyme genes that, in addition, ultimately compromise brain functions, leading over time to the complex alterations that characterize advanced sporadic Alzheimer’s disease. The identification of the genes involved in Alzheimer’s disease induced by ischemia will enable to further define the events leading to sporadic Alzheimer’s disease-related abnormalities. Additionally, knowledge gained from the above investigations should facilitate the elaboration of the effective treatment and/or prevention of Alzheimer’s disease.
Collapse
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5 Str., 02-106, Warsaw, Poland,
| | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Nakajima T, Ochi S, Oda C, Ishii M, Ogawa K. Ischemic preconditioning attenuates of ischemia-induced degradation of spectrin and tau: implications for ischemic tolerance. Neurol Sci 2010; 32:229-39. [DOI: 10.1007/s10072-010-0359-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 06/15/2010] [Indexed: 10/19/2022]
|
20
|
Zheng GQ, Wang XM, Wang Y, Wang XT. Tau as a potential novel therapeutic target in ischemic stroke. J Cell Biochem 2010; 109:26-9. [PMID: 19921714 DOI: 10.1002/jcb.22408] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Stroke is associated with high mortality and major disability burdens worldwide, but there are few effective and widely available therapies. Tau plays an important role in promoting microtubule assembly and stabilizing microtubule networks with phosphorylation regulating these functions. Based on the "ischemia-reperfusion theory" of Alzheimer's disease, some previous studies have focused on the relationship of tau and Alzheimer lesions in experimental brain ischemia. Thus, we hypothesize that the alterations in phosphorylation of tau are critical to microtubule dynamics and metabolism, and contribute to the pathophysiologic mechanisms during brain ischemia and/or reperfusion processes. We infer that regulation of phosphorylation of tau may be considered as a potential new therapeutic target in ischemic stroke.
Collapse
Affiliation(s)
- Guo-Qing Zheng
- Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical College, Wenzhou 325027, China
| | | | | | | |
Collapse
|
21
|
Pluta R, Ułamek M, Jabłoński M. Alzheimer's mechanisms in ischemic brain degeneration. Anat Rec (Hoboken) 2010; 292:1863-81. [PMID: 19943340 DOI: 10.1002/ar.21018] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
There is increasing evidence for influence of Alzheimer's proteins and neuropathology on ischemic brain injury. This review investigates the relationships between beta-amyloid peptide, apolipoproteins, presenilins, tau protein, alpha-synuclein, inflammation factors, and neuronal survival/death decisions in brain following ischemic episode. The interactions of these molecules and influence on beta-amyloid peptide synthesis and contribution to ischemic brain degeneration and finally to dementia are reviewed. Generation and deposition of beta-amyloid peptide and tau protein pathology are important key players involved in mechanisms in ischemic neurodegeneration as well as in Alzheimer's disease. Current evidence suggests that inflammatory process represents next component, which significantly contribute to degeneration progression. Although inflammation was initially thought to arise secondary to ischemic neurodegeneration, recent studies present that inflammatory mediators may stimulate amyloid precursor protein metabolism by upregulation of beta-secretase and therefore are able to establish a vicious cycle. Functional brain recovery after ischemic lesion was delayed and incomplete by an injury-related increase in the amount of the neurotoxic C-terminal of amyloid precursor protein and beta-amyloid peptide. Moreover, ischemic neurodegeneration is strongly accelerated with aging, too. New therapeutic alternatives targeting these proteins and repairing related neuronal changes are under development for the treatment of ischemic brain consequences including memory loss prevention.
Collapse
Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 Str., Warsaw, Poland.
| | | | | |
Collapse
|
22
|
Ichihara K, Uchihara T, Nakamura A, Suzuki Y, Mizutani T. Selective Deposition of 4-Repeat Tau in Cerebral Infarcts. J Neuropathol Exp Neurol 2009; 68:1029-36. [DOI: 10.1097/nen.0b013e3181b56bf4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
23
|
Gordon-Krajcer W, Kozniewska E, Lazarewicz JW, Ksiezak-Reding H. Differential changes in phosphorylation of tau at PHF-1 and 12E8 epitopes during brain ischemia and reperfusion in gerbils. Neurochem Res 2006; 32:729-37. [PMID: 17191139 DOI: 10.1007/s11064-006-9199-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Accepted: 10/11/2006] [Indexed: 10/23/2022]
Abstract
Cortical neurons are vulnerable to ischemic insult, which may cause cytoskeletal changes and neurodegeneration. Tau is a microtubule-associated protein expressed in neuronal and glial cells. We examined the phosphorylation status of tau protein in the gerbil brain cortex during 5 min ischemia induced by bilateral common carotid artery occlusion followed by reperfusion for 20 min to 7 days. Control brain homogenates contained 63, 65 and 68 kD polypeptides of tau immunoreactive with Alz 50, Tau 14 and Tau 46 antibodies raised against non-phosphorylated tau epitopes. Gerbil tau was also immunoreactive with some (PHF-1 and 12E8) but not all (AT8, AT100, AT180 and AT270) antibodies raised against phosphorylated tau epitopes. PHF-1 recognized a single 68 kD polypeptide and 12E8 bound the 63 kD polypeptide. During 5 min ischemia, PHF-1 immunoreactivity declined to 6%, then recovered to control levels after 20 min of blood recirculation and subsequently increased above control values 3 and 7 days later. In contrast, 12E8 immunoreactivity remained stable during ischemia and reperfusion. Our results suggest that the two phosphorylated epitopes of tau are regulated by different mechanisms and may play different roles in microtubule dynamics. They may also define various pools of neuronal/glial cells vulnerable to ischemia.
Collapse
Affiliation(s)
- W Gordon-Krajcer
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10029, USA
| | | | | | | |
Collapse
|
24
|
Briones TL, Woods J, Wadowska M, Rogozinska M. Amelioration of cognitive impairment and changes in microtubule-associated protein 2 after transient global cerebral ischemia are influenced by complex environment experience. Behav Brain Res 2005; 168:261-71. [PMID: 16356557 DOI: 10.1016/j.bbr.2005.11.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 11/13/2005] [Accepted: 11/14/2005] [Indexed: 11/17/2022]
Abstract
In this study we examined whether expression of microtubule-associated protein 2 (MAP2) after transient global cerebral ischemia can be influenced by behavioral experience and if the changes are associated with functional improvement. Rats received either ischemia or sham surgery then assigned to: complex environment housing (EC) or social housing (SC) as controls for 14 days followed by water maze testing. Upregulation of MAP2 was seen in all ischemic animals with a significant overall increase evident in the EC housed rats. Behaviorally, all animals learned to perform the water maze task over time but the ischemia SC rats had the worst performance overall while all the EC housed animals demonstrated the best performance in general. Regression analysis showed that increase MAP2 expression was able to explain some of the variance in the behavioral parameters in the water maze suggesting that this cytoskeletal protein probably played a role in mediating enhanced functional outcomes.
Collapse
Affiliation(s)
- Teresita L Briones
- Department of Medical-Surgical Nursing, University of Illinois, Chicago, IL 60612, USA.
| | | | | | | |
Collapse
|
25
|
Liu R, Pei JJ, Wang XC, Zhou XW, Tian Q, Winblad B, Wang JZ. Acute anoxia induces tau dephosphorylation in rat brain slices and its possible underlying mechanisms. J Neurochem 2005; 94:1225-34. [PMID: 15992372 DOI: 10.1111/j.1471-4159.2005.03270.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Abnormal phosphorylation of microtubule-associated protein tau plays a critical role in Alzheimer's disease (AD), together with a distinct decrease of energy metabolism in the affected brain regions. To explore the effect of acute energy crisis on tau phosphorylation and the underlying mechanisms, we incubated rat brain slices in artificial cerebrospinal fluid (aCSF) at 37 degrees C with or without an oxygen supply, or in aCSF with low glucose concentrations. Then, the levels of total, phosphorylated and unphosphorylated tau, as well as the activities and levels of protein phosphatase (PP)-1, PP-2A, glycogen synthase kinase 3 (GSK-3), extracellular signal-regulated protein kinase (ERK) and C-jun amino terminal kinase (JNK), were measured. It was found, unexpectedly, that tau was significantly dephosphorylated at Ser396/Ser404 (PHF-1), Ser422 (R145), Ser199/Ser202 (Tau-1), Thr181 (AT270), Ser202/Thr205 (AT8) and Thr231 (AT180) by acute anoxia for 30 min or 120 min. The activity of PP-2A and the level of dephosphorylated PP-2A catalytic subunit at tyrosine 307 (Tyr307) were simultaneously increased. The active forms of ERK1/2 and JNK1/2 were decreased under anoxic incubation. The PP-2A inhibitor, okadaic acid (OA, 0.75 microm), completely prevented tau from acute anoxia-induced dephosphorylation and restored the active forms of ERK1/2 and JNK1/2 to the control level. The activities and protein levels of GSK-3 and PP-1 showed no change during acute anoxia. These data suggest that acute anoxia induces tau dephosphorylation, and that PP-2A may play a key role in tau dephosphorylation induced by acute anoxia.
Collapse
Affiliation(s)
- Rong Liu
- Department of Pathophysiology, Tongji Medical College, HuaZhong University of Science and Technology, Wuhan, China
| | | | | | | | | | | | | |
Collapse
|
26
|
Henrich-Noack P, Gorkin AG, Krautwald K, Pforte C, Schröder UH, Reymann KG. Tetanus-induced re-activation of evoked spiking in the post-ischemic dentate gyrus. Neuroscience 2005; 133:571-81. [PMID: 15885918 DOI: 10.1016/j.neuroscience.2005.02.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 02/17/2005] [Accepted: 02/18/2005] [Indexed: 11/25/2022]
Abstract
This study aimed at investigating and influencing the basic electrophysiological functions and neuronal plasticity in the dentate gyrus in freely moving rats at several time-points after global ischemia. Although neuronal death was induced selectively in the cornu ammonis, subfield 1 (CA1)-region of the hippocampus, we found an additional loss of the population spike in the dentate gyrus after stimulation of the perforant path. Input/output-measurements revealed that as early as 1 day post-ischemia population spike generation in the granular cell layer is greatly decreased when compared with pre-ischemic values and to sham-operated animals, despite an apparently intact morphology of granular cells as evidenced by Nissl-staining. In contrast, the synaptic transmission (excitatory postsynaptic field potential) shows no significant difference when comparing values before and after ischemia and ischemic and sham-operated animals. Despite reduced output function, indicated by very small population spike amplitudes, long lasting potentiation can be induced 10 days after ischemia. Surprisingly, even "silent" populations of neurons, which appear selectively post-ischemia and do not show any evoked population spike, can be re-activated by tetanisation which is followed by a normal appearing long-term potentiation. However, this functional recovery seems to be partial and transient under current conditions: population spike-values do not reach pre-ischemic values and return to the low pre-tetanic baseline values the next day. Electrophysiological measurements ex vivo after ischemia indicate that the neuronal dysfunction in the dentate gyrus is not due to locally destroyed structures but that the activity of granular cells is merely suppressed only under in vivo conditions. In summary, global ischemia leaves a neighboring morphologically intact input area, functionally impaired. However, neuronal function can be partially regenerated by electrophysiological tetanic stimulation.
Collapse
Affiliation(s)
- P Henrich-Noack
- Research Institute for Applied Neurosciences, FAN gGmbH, ZENIT, Leipziger Str. 44, 39120 Magdeburg, Germany.
| | | | | | | | | | | |
Collapse
|
27
|
Zambrano CA, Egaña JT, Núñez MT, Maccioni RB, González-Billault C. Oxidative stress promotes tau dephosphorylation in neuronal cells: the roles of cdk5 and PP1. Free Radic Biol Med 2004; 36:1393-402. [PMID: 15135175 DOI: 10.1016/j.freeradbiomed.2004.03.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2003] [Revised: 01/29/2004] [Accepted: 03/05/2004] [Indexed: 11/19/2022]
Abstract
Oxidative stress has been demonstrated to produce modifications in several intracellular proteins that lead to alterations in their activities. Alzheimer's disease is related to an increase of oxidative stress markers, which may be an early event in the progression of the disease and neurofibrillary tangles formation. Abnormal phosphorylation of tau has been implicated in the etiopathogenesis of Alzheimer's disease. By using phospho-specific antibodies, we analyzed the changes in tau phosphorylation patterns after treatment of rat hippocampal and SHSY5Y human neuroblastoma cells with H2O2. We found that tau isoforms were hypophosphorylated at the Tau1 epitope after 2 h in the presence of H2O2. The decrease in the phosphorylation levels of tau protein were prevented by pretreatment with N-acetyl-L-cysteine. These changes were shown to depend on the activity of the cdk5/p35 complex, since a 3-fold increase in substrate phosphorylation and a 2-fold increase for the complex association were observed. Also, a decrease in the amount of inhibitor-2 bound to phosphatase PP1 was found in SHSY5Y cells under oxidative stress conditions. This decrease of inhibitor-2 bound to PP1 is due to an increased phosphorylation of the inhibitor-2 protein, thus leading to increased PP1 activity. Therefore, we propose that oxidative stress-induced activation of cdk5 leads to inhibitor-2 phosphorylation, relieving its inhibitory effect on PP1.
Collapse
Affiliation(s)
- Cristian A Zambrano
- Laboratory of Cellular and Molecular Biology, Millennium Institute for Advanced Studies in Cell Biology and Biotechnology, and Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile
| | | | | | | | | |
Collapse
|
28
|
Uchihara T, Nakamura A, Arai T, Ikeda K, Tsuchiya K. Microglial tau undergoes phosphorylation-independent modification after ischemia. Glia 2004; 45:180-7. [PMID: 14730711 DOI: 10.1002/glia.10318] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tau2 is a phosphorylation-independent antibody that immunolabels neurofibrillary tangles (NFTs) of Alzheimer type and microglia around ischemic foci on formalin-fixed, paraffin-embedded sections. We found that copresence of polyethyleneglycol-p-isooctylphenyl ether (Triton X-100; TX) with tau2 abolished its immunoreactivity (IR) in these microglia but not its IR on NFTs. Tau2-immunoreactive bands, exclusively retrieved in Tris-soluble fraction of brain homogenates from ischemic foci, normal human and bovine brains, were of similar electrophoretic mobility, indicating that tau2 IR in these microglia is unrelated to hyperphosphorylation of tau. These tau2-immunoreactive bands except those from bovine brain were abolished in the copresence of TX. This was not due to washing out of tau, because similar immunoreactive bands were detectable with another antitau antibody even under a higher concentration of TX and because washing after TX exposure restored similar tau2 IR both on immunohistochemistry and immunoblot. These findings are explained if tau, modified after ischemia, undergoes a reversible conformational change on TX exposure. Because conformation at Ser101 of bovine tau is crucial for its affinity to tau2, this Ser-like conformation mimicked by its human counterpart Pro may represent pathological modification of tau shared by microglia around ischemic foci and NFTs. Relative resistance of tau2 epitope in NFTs to TX exposure suggests that tau woven into NFTs confers additional stability to this pathological modification on tau2 epitope. Susceptibility of tau2 epitope to TX, seen in these microglia, is shared with glial cytoplasmic inclusions and will show its conformational state to be different from that in NFTs.
Collapse
Affiliation(s)
- Toshiki Uchihara
- Department of Neuropathology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashi-dai, Fuchu, Tokyo 183-8526, Japan.
| | | | | | | | | |
Collapse
|
29
|
Dudas B, Hanin I, Rose M, Wülfert E. Protection against inflammatory neurodegeneration and glial cell death by 7β-hydroxy epiandrosterone, a novel neurosteroid. Neurobiol Dis 2004; 15:262-8. [PMID: 15006696 DOI: 10.1016/j.nbd.2003.11.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2003] [Revised: 10/03/2003] [Accepted: 11/03/2003] [Indexed: 10/26/2022] Open
Abstract
It has been demonstrated that neuroprotective effects of dehydroepiandrosterone (DHEA) may be mediated by its 7alpha- and 7beta-hydroxy derivatives. Epiandrosterone is also converted to 7beta-hydroxy epiandrosterone (7beta-OH EPIA) in numerous tissues. The aim of the present study was to establish whether treatment with 7beta-hydroxy epiandrosterone has a neuroprotective effect in animal models of Alzheimer's disease (AD) lesions. Intra-amygdaloid administration of amyloid beta [Abeta(25-35)] increased the number of tau-positive cells in the ipsilateral hippocampus. Intracerebroventricular administration of ethylcholine aziridinium (AF64A) caused cholinergic damage in the septum, and glial lesions in the lateral septal nucleus and in the lateral zones of the hippocampus. These effects were almost completely prevented when animals were treated subcutaneously (b.i.d.) for 10 days with 0.1 mg/kg 7beta-hydroxy epiandrosterone. These findings indicate that 7beta-hydroxy epiandrosterone has powerful cytoprotective effects suggesting that (a) this neurosteroid may have therapeutic potential in various neurodegenerative conditions such as Alzheimer's disease, and (b) 7beta-hydroxy steroids may constitute a novel class of endogenous neuroprotective agents.
Collapse
Affiliation(s)
- Bertalan Dudas
- Lake Erie College of Osteopathic Medicine, Maywood, IL 16509, USA.
| | | | | | | |
Collapse
|
30
|
Liu D, Guo H, Griffin JH, Fernández JA, Zlokovic BV. Protein S confers neuronal protection during ischemic/hypoxic injury in mice. Circulation 2003; 107:1791-6. [PMID: 12665496 DOI: 10.1161/01.cir.0000058460.34453.5a] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Protein S is an antithrombotic factor that also exhibits mitogenic activity. Thus, we hypothesized that protein S may control cerebrovascular thrombosis in stroke and protect brain tissue from ischemic injury. METHODS AND RESULTS We studied protein S in a murine in vivo model of stroke and an in vitro model of neuronal hypoxia/reoxygenation injury. Animals received purified human plasma-derived protein S or vehicle intravenously 10 minutes after initiation of middle cerebral artery occlusion followed by reperfusion. Protein S at 0.2 to 2 mg/kg significantly improved the motor neurological deficit by 3.8- to 3.2-fold and reduced infarction and edema volumes by 45% to 54% and 45% to 62%, respectively. Protein S at 2 mg/kg improved postischemic cerebral blood flow by 21% to 26% and reduced brain fibrin deposition and infiltration with neutrophils by 40% and 53%, respectively. Intracerebral bleeding was not observed with protein S. Protein S protected ischemic neurons in vivo and cultured neurons from hypoxia/reoxygenation-induced apoptosis in a time- and dose-dependent manner. Recombinant human protein S exerted protective effects from hypoxia-induced damage similar to the plasma-derived protein S both in vivo and in vitro. CONCLUSIONS Protein S is a significant neuroprotectant during ischemic brain injury with direct effects on neurons and antithrombotic effects. Thus, protein S could be a prototype of a new class of agents for clinical stroke with combined direct neuronal protective effects and systemic antithrombotic and antiinflammatory activities.
Collapse
Affiliation(s)
- Dong Liu
- Frank P. Smith Neurosurgical Research Laboratory, Division of Neurovascular Biology, University of Rochester Medical Center, 601 Elmwood Ave, Box 645, Rochester, NY 14642, USA
| | | | | | | | | |
Collapse
|
31
|
Pettigrew LC, Holtz ML, Minger SL, Craddock SD. Glutamate receptor antagonists modulate heat shock protein response in focal brain ischemia. Neurol Res 2003; 25:201-7. [PMID: 12635523 DOI: 10.1179/016164103101201201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Neurons and glia reacting to ischemic injury exhibit delayed expression of heat shock proteins (HSPs). We tested the hypothesis that glutamate receptor antagonists alter neuronal and glial activation during focal cerebral ischemia, as shown by spatio-temporal changes in HSP immunoreactivity. Rats underwent focal ischemia by permanent occlusion of the middle cerebral artery. All animals were pre-treated with NBQX (30 mg kg-1), a competitive antagonist of the AMPA/kainate receptor, or CGS-19755 (10 mg kg-1), a competitive NMDA receptor antagonist, and euthanatized after 6 or 24 h of ischemia to demonstrate regional immunoreactivity of HSP-72 or 32 in brain. Neurons immunolabeled for HSP-72 appeared in the penumbral region adjacent to the infarct at 24 h and increased in number and distribution after pretreatment with NBQX or CGS-19755. Immunolabeling for HSP-32 revealed that pre-treatment with CGS-19755 caused ramified glia to infiltrate the ischemic cortex at 6 h, a pattern that was not seen in ischemic controls until 24 h. Blockade of the NMDA or AMPA/kainate receptor modulates cellular stress responses in both neurons and glia within the developing infarct. We conclude that early, rather than delayed, expression of HSP-32 is a sensitive indicator of glial activation induced specifically by CGS-19755.
Collapse
Affiliation(s)
- L Creed Pettigrew
- Department of Neurology, University of Kentucky College of Medicine, Department of Veterans Affairs Medical Center, Lexington, Kentucky, USA
| | | | | | | |
Collapse
|
32
|
Akulinin VA, Dahlstrom A. Quantitative analysis of MAP2 immunoreactivity in human neocortex of three patients surviving after brain ischemia. Neurochem Res 2003; 28:373-8. [PMID: 12608711 DOI: 10.1023/a:1022401922669] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Transient global ischemia caused by cardiac arrest results in lesions that involve all brain structures. The aim of this study was to investigate the distribution of MAP2 immunoreactivity in neurons in the brain of patients surviving for various times after an ischemic incident, using confocal laser scanning microscopy. We performed a quantitative analysis of the distribution and density of MAP2-positive structures in human neocortical areas after survival times of 1 week, 3 months, and 1 year after the cardiac arrest. Three important observations were made in the present study: (i) in all human brain areas investigated (motor, temporal, frontal, and visual cortex) a decrease of MAP2 immunoreactivity was found; (ii) in all studied areas the most significant decrease in MAP2 was found in layers II-III, compared with layers V-VII; (iii) the decrease of MAP2 immunoreactivity in layers II-III was related to the duration of the postischemic period. The maximal decrease, by 66.3% (P < .05), in MAP2-positive pyramidal neurons, was observed in layers II-III in the motor cortex after 1 year of survival after cardiac arrest.
Collapse
Affiliation(s)
- Victor A Akulinin
- Department of Histology, Embryology and Cell Biology, Omsk State Medical Academy, Lenin 1 Omsk 644099, Russia.
| | | |
Collapse
|
33
|
Grilli M, Diodato E, Lozza G, Brusa R, Casarini M, Uberti D, Rozmahel R, Westaway D, St George-Hyslop P, Memo M, Ongini E. Presenilin-1 regulates the neuronal threshold to excitotoxicity both physiologically and pathologically. Proc Natl Acad Sci U S A 2000; 97:12822-7. [PMID: 11070093 PMCID: PMC18848 DOI: 10.1073/pnas.97.23.12822] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A direct pathophysiological role of Familial Alzheimer's Disease (FAD)-associated Presenilin 1 (PS1) mutations in neuronal vulnerability remains a controversial matter. We evaluated the relationship between PS1 and excitotoxicity in four different experimental models of neurotoxicity by using primary neurons from (i) transgenic (tg) mice overexpressing a human FAD-linked PS1 variant (L286V mutation), (ii) tg mice overexpressing human wild-type (wt) PS1, (iii) PS1 knockout mice, and (iv) wt mice in which PS1 gene expression was knocked down by antisense treatment. We found that primary neurons overexpressing mutated PS1 showed an increased vulnerability to both excitotoxic and hypoxic-hypoglycemic damage when compared with neurons obtained from either mice overexpressing human wt PS1 or in wt mice. In addition, reduced excitotoxic damage was obtained in neurons in which PS1 expression was absent or diminished. Data obtained in in vivo experimental models of excitotoxicity partially supported the in vitro observations. Accelerated neuronal death was demonstrated in the hippocampus of mice overexpressing mutated PS1 after peripheral administration of kainic acid in comparison with wt animals. However, measurement of the infarct volume after middle cerebral artery occlusion did not show significant difference between the two animal groups. The results altogether suggest that expression of FAD-linked PS1 variants increases the vulnerability of neurons to a specific type of damage in which excitotoxicity plays a relevant role. In addition, they support the view that reduction of endogenous PS1 expression results in neuroprotection.
Collapse
Affiliation(s)
- M Grilli
- Schering-Plough Research Institute, Department of Central Nervous System/Cardiovascular Research, San Raffaele Science Park, Milan, Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Uchihara T, Tsuchiya K, Nakamura A, Ikeda K. Appearance of tau-2 immunoreactivity in glial cells in human brain with cerebral infarction. Neurosci Lett 2000; 286:99-102. [PMID: 10825646 DOI: 10.1016/s0304-3940(00)01103-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Appearance of tau epitopes in ischemic foci was investigated immunohistochemically on a series of autopsied human brains using a panel of anti-tau antibodies. While neurons were immunopositive for Alz-50, microglia and oligodendroglia around ischemic foci abundantly contained tau-2 immunoreactivity. Some astrocytes contained tau-2 immunoreactive granules in their cytoplasm. This difference suggests that neurons and glia react differently to an ischemic insult by exhibiting different tau epitopes. Immunohistochemical visualization tau-2 epitope represents its conformational change, as was reported with neurofibrillary tangles of Alzheimer type. Lack of argyrophilia in any of these tau-immunoreactive cells distinguishes them from tau-immunoreactive structures seen in various neurodegenerative disorders.
Collapse
Affiliation(s)
- T Uchihara
- Department of Neuropathology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashi-dai, Fuchu, Tokyo, 183-8526, Japan.
| | | | | | | |
Collapse
|
35
|
Ikeda K, Akiyama H, Arai T, Kondo H, Haga C, Tsuchiya K, Yamada S, Murayama S, Hori A. Neurons containing Alz-50-immunoreactive granules around the cerebral infarction: evidence for the lysosomal degradation of altered tau in human brain? Neurosci Lett 2000; 284:187-9. [PMID: 10773430 DOI: 10.1016/s0304-3940(00)01009-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Little is known about the metabolic process of tau and tau-derived substances. Alz-50- and tau 2-immunoreactivities in intracellular granules of neurons were observed in regions surrounding infarcted foci in the human cerebral cortex. Ultrastructurally, these granules in the fresh infarcted region exhibited primary lysosome-like structures, while those in old infarctions were lipofuscin. These findings indicate that tau is metabolized within lysosomes in neurons damaged by ischemic injury in human cortical penumbra. Alz-50-positive granules were more prominent in fresh infarction than in old infarction. After undergoing degradation and modification, altered tau might remain, at least partially, in secondary lysosomes.
Collapse
Affiliation(s)
- K Ikeda
- Department of Neuropathology, Tokyo Institute of Psychiatry, 2-1-8, Kamikitazawa, Setagaya-ku, Tokyo, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Abstract
This review is directed at understanding how neuronal death occurs in two distinct insults, global ischemia and focal ischemia. These are the two principal rodent models for human disease. Cell death occurs by a necrotic pathway characterized by either ischemic/homogenizing cell change or edematous cell change. Death also occurs via an apoptotic-like pathway that is characterized, minimally, by DNA laddering and a dependence on caspase activity and, optimally, by those properties, additional characteristic protein and phospholipid changes, and morphological attributes of apoptosis. Death may also occur by autophagocytosis. The cell death process has four major stages. The first, the induction stage, includes several changes initiated by ischemia and reperfusion that are very likely to play major roles in cell death. These include inhibition (and subsequent reactivation) of electron transport, decreased ATP, decreased pH, increased cell Ca(2+), release of glutamate, increased arachidonic acid, and also gene activation leading to cytokine synthesis, synthesis of enzymes involved in free radical production, and accumulation of leukocytes. These changes lead to the activation of five damaging events, termed perpetrators. These are the damaging actions of free radicals and their product peroxynitrite, the actions of the Ca(2+)-dependent protease calpain, the activity of phospholipases, the activity of poly-ADPribose polymerase (PARP), and the activation of the apoptotic pathway. The second stage of cell death involves the long-term changes in macromolecules or key metabolites that are caused by the perpetrators. The third stage of cell death involves long-term damaging effects of these macromolecular and metabolite changes, and of some of the induction processes, on critical cell functions and structures that lead to the defined end stages of cell damage. These targeted functions and structures include the plasmalemma, the mitochondria, the cytoskeleton, protein synthesis, and kinase activities. The fourth stage is the progression to the morphological and biochemical end stages of cell death. Of these four stages, the last two are the least well understood. Quite little is known of how the perpetrators affect the structures and functions and whether and how each of these changes contribute to cell death. According to this description, the key step in ischemic cell death is adequate activation of the perpetrators, and thus a major unifying thread of the review is a consideration of how the changes occurring during and after ischemia, including gene activation and synthesis of new proteins, conspire to produce damaging levels of free radicals and peroxynitrite, to activate calpain and other Ca(2+)-driven processes that are damaging, and to initiate the apoptotic process. Although it is not fully established for all cases, the major driving force for the necrotic cell death process, and very possibly the other processes, appears to be the generation of free radicals and peroxynitrite. Effects of a large number of damaging changes can be explained on the basis of their ability to generate free radicals in early or late stages of damage. Several important issues are defined for future study. These include determining the triggers for apoptosis and autophagocytosis and establishing greater confidence in most of the cellular changes that are hypothesized to be involved in cell death. A very important outstanding issue is identifying the critical functional and structural changes caused by the perpetrators of cell death. These changes are responsible for cell death, and their identity and mechanisms of action are almost completely unknown.
Collapse
Affiliation(s)
- P Lipton
- Department of Physiology, University of Wisconsin School of Medicine, Madison, Wisconsin, USA
| |
Collapse
|
37
|
Geddes JW, Chang NG, Ackley DC, Soultanian NS, McGillis JP, Yokel RA. Postmortem elevation in extracellular glutamate in the rat hippocampus when brain temperature is maintained at physiological levels: implications for the use of human brain autopsy tissues. Brain Res 1999; 831:104-12. [PMID: 10411988 DOI: 10.1016/s0006-8993(99)01403-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Postmortem alterations in the neuronal cytoskeleton resemble some aspects of the cytoskeletal disruption associated with neurodegenerative disorders, and are also similar to those observed following ischemia and produced by excitotoxins in vivo and in vitro. This suggests the involvement of excitotoxic mechanisms during the postmortem interval. The purpose of this study was to determine if extracellular levels of glutamate are elevated postmortem. Extracellular levels of GABA and taurine were also monitored using in vivo microdialysis. These three amino acids were analyzed using high-performance liquid chromatography. When postmortem rat brain temperature cooled rapidly to near room temperature, dialysate concentrations of glutamate were not increased in the hippocampal CA1 region during a 2-h postmortem interval, although increased extracellular levels of GABA and taurine were observed. In contrast, maintenance of brain temperature at 37 degrees C resulted in a 12-to-40 fold elevation in extracellular glutamate levels 20-120 min postmortem. In addition, the elevation in dialysate taurine concentration was greater than that observed in rats in which postmortem brain temperature was not maintained. Excitatory amino acid antagonists, NBQX (2, 3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline) and MK-801 (dizocilpine, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cylohepten-5, 10-imine hydrogen maleate blocked the additional elevation in taurine associated with maintaining brain at 37 degrees C, but had less robust effects against glutamate and GABA release. The results indicate that extracellular concentrations of glutamate, taurine and GABA increase in postmortem rat brain when physiologic temperatures are maintained, but that these increases are blunted when brain temperature decreases. After death, the human brain cools much more slowly than does the rat brain. Therefore, extracellular glutamate levels are likely to increase in the postmortem human brain and may contribute to excitotoxic neuronal damage occurring in the interval between death and autopsy.
Collapse
Affiliation(s)
- J W Geddes
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536-0230, USA.
| | | | | | | | | | | |
Collapse
|
38
|
Morioka M, Hamada J, Ushio Y, Miyamoto E. Potential role of calcineurin for brain ischemia and traumatic injury. Prog Neurobiol 1999; 58:1-30. [PMID: 10321795 DOI: 10.1016/s0301-0082(98)00073-2] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Calcineurin belongs to the family of Ca2+/calmodulin-dependent protein phosphatase, protein phosphatase 2B. Calcineurin is the only protein phosphatase which is regulated by a second messenger, Ca2+. Furthermore, calcineurin is highly localized in the central nervous system, especially in those neurons vulnerable to ischemic and traumatic insults. For these reasons, calcineurin is considered to play important roles in neuron-specific functions. Recently, on the basis of the finding that FK506 and cyclosporin A serve as calcineurin-specific inhibitors, this enzyme has become the subject of much study. It is clear that calcineurin is involved in many neuronal (or non-neuronal) functions such as neurotransmitter release, regulation of receptor functions, signal transduction systems, neurite outgrowth, gene expression and neuronal cell death. In this review, we describe the calcineurin functions, functions of the substrates, and the pathogenesis of traumatic and ischemic insults, and we discuss the potential role of calcineurin. There are many similarities in traumatic and ischemic pathogenesis of the brain in which the release of excessive glutamate is followed by an intracellular Ca2+ increase. However, the intracellular cascade which leads to neuronal cell death after the release of excess Ca2+ is unclear. Although calcineurin is thought to be a key toxic enzyme on the basis of studies using immunosuppressants (FK506 or cyclosporin A), many of the functions of the substrates for calcineurin protect against neuronal cell death. We concluded that calcineurin is a bi-directional enzyme for neuronal cell death, having protective and toxic actions, and the balance of the bi-directional effects may be important in ischemic and traumatic pathogenesis.
Collapse
Affiliation(s)
- M Morioka
- Department of Neurosurgery, Kumamoto University School of Medicine, Japan.
| | | | | | | |
Collapse
|
39
|
Glutamate Receptors and Excitotoxic Mechanisms in Alzheimer’s Disease. Cereb Cortex 1999. [DOI: 10.1007/978-1-4615-4885-0_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
|
40
|
Korneyev AY. Stress-induced tau phosphorylation in mouse strains with different brain Erk 1 + 2 immunoreactivity. Neurochem Res 1998; 23:1539-43. [PMID: 9821159 DOI: 10.1023/a:1020980004539] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Quantitative blot immunolabeling techniques were used to compare the effect of cold water stress (CWS) on the phosphorylation of brain tau protein in two strains of C57BL/6J mice: ob/ob and ob/+. CWS induced immediate, significant (4-6 fold) and continuous accumulation of Alzheimer's like forms of tau phosphorylated at Ser 202. The effect was considerably (150-200%) higher in ob/ob mice compared to ob/+ mice. By contrast, the unphosphorylated tau immunoreactivity decreased after the CWS, whereas no changes were detected in the abundance of several other antigens. The level of anti Erk 1 + 2 immunoreactivity corresponding to 36-37 kDa polypeptide was 2-3 fold higher in ob/ob than in ob/+ mice. No strain differences were detected in the abundance of several other protein kinases. Obtained results support the hypothesis that Erk 1 or 2 like protein kinase may be involved in the restructuring of neuronal cytoskeleton in response to environmental stress.
Collapse
|
41
|
Burkhart KK, Beard DC, Lehman RA, Billingsley ML. Alterations in tau phosphorylation in rat and human neocortical brain slices following hypoxia and glucose deprivation. Exp Neurol 1998; 154:464-72. [PMID: 9878182 DOI: 10.1006/exnr.1998.6899] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tau is a microtubule-associated protein which is regulated by phosphorylation. Highly phosphorylated tau does not bind microtubules and is the main component of the paired helical filaments seen in Alzheimer's and related neurodegenerative diseases. Recent reports suggested that patterns of tau phosphorylation changed following ischemia and/or reperfusion in vivo. We used an in vitro model employing rat and human neocortical slices to investigate changes in tau phosphorylation which accompany oxygen and glucose deprivation. Western blotting with polyclonal and phosphorylation-sensitive Tau-1 monoclonal antisera was used to monitor changes in tau which accompanied conditions of oxygen and glucose deprivation and reestablishment of these nutrients. In vitro hypoglycemia/hypoxia caused tau to undergo significant dephosphorylation in both rat and human neocortical slices after 30 and 60 min of deprivation. This dephosphorylation was confirmed using immunoprecipitation experiments after radiolabeling tau and other proteins with 32Pi. Okadaic acid, a phosphatase inhibitor, was able to prevent tau dephosphorylation in both control and ischemic slices. Lubeluzole, a benzothiazole derivative with in vivo neuroprotective activity, did not significantly alter patterns of tau phosphorylation. Restoration of oxygen and glucose following varied periods of in vitro hypoxia/hypoglycemia (15-60 min) led to an apparent recovery in phosphorylated tau. These data suggest that tau undergoes a rapid, but reversible dephosphorylation following brief periods of in vitro hypoxia/hypoglycemia in brain slices and that changes in tau phosphorylation help determine the extent of recovery following oxygen and glucose deprivation.
Collapse
Affiliation(s)
- K K Burkhart
- Center for Emergency Medical Services, Department of Pharmacology, The Milton S. Hershey Medical Center, Pennsylvania State University, 500 University Drive, Hershey, Pennsylvania, 17033, USA
| | | | | | | |
Collapse
|
42
|
Minger SL, Geddes JW, Holtz ML, Craddock SD, Whiteheart SW, Siman RG, Pettigrew LC. Glutamate receptor antagonists inhibit calpain-mediated cytoskeletal proteolysis in focal cerebral ischemia. Brain Res 1998; 810:181-99. [PMID: 9813316 DOI: 10.1016/s0006-8993(98)00921-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excitatory amino acids may promote microtubular proteolysis observed in ischemic neuronal degeneration by calcium-mediated activation of calpain, a neutral protease. We tested this hypothesis in an animal model of focal cerebral ischemia without reperfusion. Spontaneously hypertensive rats were treated with 2, 3-dihydroxy-6-nitro-7-sulfamoyl-benzo-(F)quinoxaline (NBQX), a competitive antagonist of the neuronal receptor for alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), or cis-4-[phosphono-methyl]-2-piperidine carboxylic acid (CGS 19755), a competitive antagonist of the N-methyl-d-aspartate (NMDA) receptor. After treatment, all animals were subjected to permanent occlusion of the middle cerebral artery for 6 or 24 h. Infarct volumes measured in animals pretreated with CGS 19755 after 24 h of ischemia were significantly smaller than those quantified in ischemic controls. Rats pretreated with NBQX showed partial amelioration of cytoskeletal injury with preserved immunolabeling of microtubule-associated protein 2 (MAP 2) at 6 and 24 h and reduced accumulation of calpain-cleaved spectrin byproducts only at 6 h. Prevention of cytoskeletal damage was more effective after pretreatment with CGS 19755, as shown by retention of MAP 2 immunolabeling and significant restriction of calpain activity at both 6 and 24 h. Preserved immunolabeling of tau protein was observed at 6 and 24 h only in animals pretreated with CGS 19755. Western analysis performed on ischemic cortex taken from controls or rats pretreated with either NBQX or CGS 19755 suggested that loss of tau protein immunoreactivity was caused by dephosphorylation, rather than proteolysis. These results demonstrate a crucial link between excitotoxic neurotransmission, microtubular proteolysis, and neuronal degeneration in focal cerebral ischemia.
Collapse
Affiliation(s)
- S L Minger
- The Stroke Program of the University of Kentucky Chandler Medical Center, USA
| | | | | | | | | | | | | |
Collapse
|
43
|
Regional selective neuronal degeneration after protein phosphatase inhibition in hippocampal slice cultures: evidence for a MAP kinase-dependent mechanism. J Neurosci 1998. [PMID: 9736650 DOI: 10.1523/jneurosci.18-18-07296.1998] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The regional selectivity and mechanisms underlying the toxicity of the serine/threonine protein phosphatase inhibitor okadaic acid (OA) were investigated in hippocampal slice cultures. Image analysis of propidium iodide-labeled cultures revealed that okadaic acid caused a dose- and time-dependent injury to hippocampal neurons. Pyramidal cells in the CA3 region and granule cells in the dentate gyrus were much more sensitive to okadaic acid than the pyramidal cells in the CA1 region. Electron microscopy revealed ultrastructural changes in the pyramidal cells that were not consistent with an apoptotic process. Treatment with okadaic acid led to a rapid and sustained tyrosine phosphorylation of the mitogen-activated protein kinases ERK1 and ERK2 (p44/42(mapk)). The phosphorylation was markedly reduced after treatment of the cultures with the microbial alkaloid K-252a (a nonselective protein kinase inhibitor) or the MAP kinase kinase (MEK1/2) inhibitor PD98059. K-252a and PD98059 also ameliorated the okadaic acid-induced cell death. Inhibitors of protein kinase C, Ca2+/calmodulin-dependent protein kinase II, or tyrosine kinase were ineffective. These results indicate that sustained activation of the MAP kinase pathway, as seen after e.g., ischemia, may selectively harm specific subsets of neurons. The susceptibility to MAP kinase activation of the CA3 pyramidal cells and dentate granule cells may provide insight into the observed relationship between cerebral ischemia and dementia in Alzheimer's disease.
Collapse
|
44
|
Shackelford DA, Yeh RY. Dephosphorylation of tau during transient forebrain ischemia in the rat. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1998; 34:103-20. [PMID: 10327411 DOI: 10.1007/bf02815073] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The effect of transient cerebral ischemia on phosphorylation of the microtubule-associated protein (MAP) tau was investigated using the rat four-vessel occlusion model. Phosphorylation of tau is proposed to regulate its binding to microtubules, influencing the dynamics of microtubule assembly necessary for axonal growth and neurite plasticity. In this study, tau was rapidly dephosphorylated during ischemia in the hippocampus, neocortex, and striatum. Dephosphorylation of tau was observed within 5 min of occlusion and increased after 15 min in all three brain regions, regardless of their relative vulnerability to the insult. Thus, dephosphorylation of tau is an early marker of ischemia and precedes the occlusion time required to cause extensive neuronal cell death in this model. On restoration of blood flow for a little as 15 min, tau was phosphorylated at a site(s) that causes a reduction in its electrophoretic mobility. The dephosphorylation/phosphorylation of tau may alter its distribution between axon and cell body, and affect its susceptibility to proteolysis. These changes would be expected to influence microtubule stability, possibly contributing to disruption of axonal transport, but also allowing neurite remodeling in a regenerative response.
Collapse
Affiliation(s)
- D A Shackelford
- Department of Neurosciences, University of California, San Diego, La Jolla 92093-0624, USA.
| | | |
Collapse
|
45
|
Affiliation(s)
- R C Lin
- Department of Neurobiology and Anatomy, Allegheny University, Philadelphia, Pennsylvania 19102, USA.
| | | | | |
Collapse
|
46
|
Malchiodi-Albedi F, Petrucci TC, Picconi B, Iosi F, Falchi M. Protein phosphatase inhibitors induce modification of synapse structure and tau hyperphosphorylation in cultured rat hippocampal neurons. J Neurosci Res 1997. [DOI: 10.1002/(sici)1097-4547(19970601)48:5<425::aid-jnr4>3.0.co;2-g] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
47
|
Irving EA, Yatsushiro K, McCulloch J, Dewar D. Rapid alteration of tau in oligodendrocytes after focal ischemic injury in the rat: involvement of free radicals. J Cereb Blood Flow Metab 1997; 17:612-22. [PMID: 9236718 DOI: 10.1097/00004647-199706000-00003] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Glial inclusions containing the microtubule-associated protein tau are present in a variety of chronic neurodegenerative conditions. We now report a rapid and time-dependent increase of tau immunoreactivity within oligodendrocytes after focal cerebral ischemia in the rat. The number of tau positive oligodendrocytes in the ipsilateral subcortical white matter increased six- to eightfold by 40 minutes after permanent middle cerebral artery occlusion (MCAO). Tau was detected using antibodies that label both the N- and C-terminal of the protein, suggesting accumulation of full-length protein within these cells. Pretreatment with the spin trap agent alpha-phenyl-tert-butyl-nitrone (PBN)(100mg/kg) reduced the number of tau-positive oligodendrocytes by 55% in the subcortical white matter of the ischemic hemisphere compared with untreated animals at 40 minutes after MCAO. In contrast, pretreatment with glutamate receptor antagonists MK-801 (0.5 mg/kg) or 2,3-dihydroxy-6-nitro-7-sulpfamoyl-benzo(f)quinoxaline (NBQX) (2 x 30 mg/kg), failed to reduce the number of tau-positive oligodendrocytes after 40 minutes of ischemia. The results indicate that oligodendrocytes respond rapidly to an ischemic challenge and that free radical-mediated mechanisms are involved in the cascade leading to increased tau immunoreactivity.
Collapse
Affiliation(s)
- E A Irving
- Wellcome Surgical Institute, University of Glasgow, Scotland, United Kingdom
| | | | | | | |
Collapse
|
48
|
Adamec E, Mercken M, Beermann ML, Didier M, Nixon RA. Acute rise in the concentration of free cytoplasmic calcium leads to dephosphorylation of the microtubule-associated protein tau. Brain Res 1997; 757:93-101. [PMID: 9200503 DOI: 10.1016/s0006-8993(97)00166-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The objective of this study was to asses the response of the microtubule-associated protein tau to acute rise in the concentration of free cytoplasmic calcium ([Ca2+]i) in rat cortical neurons and mouse cerebellar granule cells in culture. One-hour exposure to glutamate (100 microM), N-methyl-D-aspartate (100 microM), KCl (50 mM), and ionomycin (5 microM) led to tau protein dephosphorylation as indicated by an appearance of additional faster moving bands on Western immunoblots with a phosphorylation-independent antibody and an increase in the tau-1 immunoreactivity associated with the appearance of an additional faster moving band. Lowering the extracellular concentration of Ca2+ to less than 1 microM fully prevented the drug-induced tau protein dephosphorylation indicating a dependence on Ca2+ influx from the extracellular environment. Administration of okadaic acid (inhibitor of phosphatase 1/2A) simultaneously with the above mentioned drugs decreased the drug-mediated dephosphorylation. Pre-incubation with okadaic acid fully prevented the dephosphorylation. Treatment with cypermethrin (inhibitor of phosphatase 2B) was without effect when administered either alone, simultaneously with the drugs, or pre-incubated. These findings indicate that, independently of the influx pathway, [Ca2+]i elevation leads to dephosphorylation of the microtubule-associated protein tau and implicate phosphatase 1 and/or 2A in the process.
Collapse
Affiliation(s)
- E Adamec
- Laboratories for Molecular Neuroscience, Mailman Research Center, McLean Hospital, Belmont, MA 02178, USA.
| | | | | | | | | |
Collapse
|
49
|
Hall GF, Yao J, Lee G. Human tau becomes phosphorylated and forms filamentous deposits when overexpressed in lamprey central neurons in situ. Proc Natl Acad Sci U S A 1997; 94:4733-8. [PMID: 9114060 PMCID: PMC20793 DOI: 10.1073/pnas.94.9.4733] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Microinjection of plasmids encoding human tau (htau) protein into identified lamprey reticulospinal neurons (anterior bulbar cells, or ABCs) in situ induces chronic htau expression. htau protein is transported to both the axon and dendrites of expressing ABCs by mechanisms that require the C-terminal domain of htau protein but do not require directed htau mRNA transport. htau becomes phosphorylated at the PHF-1 (Ser-396/404) and TAU-1/AT8 (Ser-199/202) epitopes throughout ABCs with heavy htau accumulations; many such cells also exhibit degenerative changes, which include the development of extracellular htau deposits. Finally, expression of htau protein fused to green fluorescent protein induced the somatodendritic accumulation of filaments containing htau when examined by immunoelectron microscopy. These results suggest that chronic expression of htau in lamprey ABCs may be useful for studying cellular mechanisms underlying tau hyperphosphorylation and filament formation in vertebrate central neurons in situ.
Collapse
Affiliation(s)
- G F Hall
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01854, USA
| | | | | |
Collapse
|
50
|
Irving EA, McCulloch J, Dewar D. The effect of postmortem delay on the distribution of microtubule-associated proteins tau, MAP2, and MAP5 in the rat. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1997; 30:253-71. [PMID: 9165490 DOI: 10.1007/bf02815102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Breakdown or disruption of the cytoskeleton has been implicated in the neurodegenerative processes of a variety of diseases, including Alzheimer disease (AD) and stroke. Studies of such diseases in the human involve the use of postmortem brain tissue. Postmortem delay may vary considerably from a few hours to a few days, and within this period, a degree of cytoskeletal breakdown may occur. It is therefore crucial to examine alterations occurring in the cytoskeleton as a result of postmortem delay and subtract these from those caused by the disease. In this study, the distribution of tau, MAP2, and MAP5 immunohistochemistry was examined following postmortem intervals of 0-72 h in the rat cerebral cortex, corpus callosum, caudate nucleus, and hippocampus. Each microtubule-associated protein (MAP) underwent unique changes that were dependent both on postmortem interval and the brain region examined. Following long postmortem delays, some of the changes in these proteins were similar to those seen in rodent models of cerebral ischemia. These results demonstrate that MAPs are not stable during postmortem delay in the rat. Therefore, caution must be exercised when interpreting changes in MAPs in human postmortem tissue, especially in cases where ischemic injury may be involved. Examination of control tissue carefully matched for postmortem delay is therefore essential to allow meaningful interpretation of cytoskeletal abnormalities in human neurodegenerative disease.
Collapse
Affiliation(s)
- E A Irving
- Wellcome Surgical Institute, University of Glasgow, UK.
| | | | | |
Collapse
|