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Yeganeh Markid T, Hosseinpour Feizi MA, Talebi M, Rezazadeh M, Khalaj-Kondori M. Gene expression investigation of four key regulators of polyadenylation and alternative adenylation in the periphery of late-onset Alzheimer's disease patients. Gene 2024; 895:148013. [PMID: 37981081 DOI: 10.1016/j.gene.2023.148013] [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] [Received: 07/11/2023] [Revised: 10/11/2023] [Accepted: 11/15/2023] [Indexed: 11/21/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is a genetic and sporadic neurodegenerative disease considered by an archetypal cognitive impairment and a decrease in less common cognitive impairment. Notably, the discovery of goals in this paradigm is still a challenge, and understanding basic mechanisms is an important step toward improving disease management. Polyadenylation (PA) and alternative polyadenylation (APA) are two of the most critical RNA processing stages in 3'UTRs that influence various AD-related genes. METHODS In this study, we assessed Cleavage and polyadenylation specificity factors 1 and 6 (CPSF1 and CPSF6), cleavage stimulation factor 1 (CSTF1), and WD Repeat Domain 33 (WDR33) genes expression in the periphery of 50 AD patients and 50 healthy individuals with age and gender-matched by quantitative real-time PCR. RESULTS Comparing AD patients with healthy people using expression analysis revealed a substantial increase in CSTF1 (posterior beta = 0.773, adjusted P-value = 0.042). Significant positive correlations were found between CSTF1 and CPSF1 (r = 0.365, P < 0.001), WDR33 (r = 0.506, P < 0.001), and CPSF6 (r = 0.446, P < 0.001) expression levels. CONCLUSION Although further research is required to determine their potential contribution to AD, our findings offer a fresh perspective on molecular regulatory pathways associated with AD pathogenic mechanisms associated with PA and APA.
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Affiliation(s)
- Tarlan Yeganeh Markid
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Iran; Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
| | | | - Mahnaz Talebi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Maryam Rezazadeh
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Iran; Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Mohammad Khalaj-Kondori
- Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran.
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2
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Mir FA, Amanullah A, Jain BP, Hyderi Z, Gautam A. Neuroepigenetics of ageing and neurodegeneration-associated dementia: An updated review. Ageing Res Rev 2023; 91:102067. [PMID: 37689143 DOI: 10.1016/j.arr.2023.102067] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 09/01/2023] [Accepted: 09/06/2023] [Indexed: 09/11/2023]
Abstract
Gene expression is tremendously altered in the brain during memory acquisition, recall, and forgetfulness. However, non-genetic factors, including environmental elements, epigenetic changes, and lifestyle, have grabbed significant attention in recent years regarding the etiology of neurodegenerative diseases (NDD) and age-associated dementia. Epigenetic modifications are essential in regulating gene expression in all living organisms in a DNA sequence-independent manner. The genes implicated in ageing and NDD-related memory disorders are epigenetically regulated by processes such as DNA methylation, histone acetylation as well as messenger RNA editing machinery. The physiological and optimal state of the epigenome, especially within the CNS of humans, plays an intricate role in helping us adjust to the changing environment, and alterations in it cause many brain disorders, but the mechanisms behind it still need to be well understood. When fully understood, these epigenetic landscapes could act as vital targets for pharmacogenetic rescue strategies for treating several diseases, including neurodegeneration- and age-induced dementia. Keeping this objective in mind, this updated review summarises the epigenetic changes associated with age and neurodegeneration-associated dementia.
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Affiliation(s)
- Fayaz Ahmad Mir
- Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - Zeeshan Hyderi
- Department of Biotechnology, Alagappa University, Karaikudi, India
| | - Akash Gautam
- Centre for Neural and Cognitive Sciences, University of Hyderabad, Hyderabad, India.
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3
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Abouhashem AS, Singh K, Srivastava R, Liu S, Mathew-Steiner SS, Gu X, Kacar S, Hagar A, Sandusky GE, Roy S, Wan J, Sen CK. The Prolonged Terminal Phase of Human Life Induces Survival Response in the Skin Transcriptome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.15.540715. [PMID: 37292819 PMCID: PMC10245562 DOI: 10.1101/2023.05.15.540715] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Human death marks the end of organismal life under conditions such that the components of the human body continue to be alive. Such postmortem cellular survival depends on the nature (Hardy scale of slow-fast death) of human death. Slow and expected death typically results from terminal illnesses and includes a prolonged terminal phase of life. As such organismal death process unfolds, do cells of the human body adapt for postmortem cellular survival? Organs with low energy cost-of-living, such as the skin, are better suited for postmortem cellular survival. In this work, the effect of different durations of terminal phase of human life on postmortem changes in cellular gene expression was investigated using RNA sequencing data of 701 human skin samples from the Genotype-Tissue Expression (GTEx) database. Longer terminal phase (slow-death) was associated with a more robust induction of survival pathways (PI3K-Akt signaling) in postmortem skin. Such cellular survival response was associated with the upregulation of embryonic developmental transcription factors such as FOXO1 , FOXO3 , ATF4 and CEBPD . Upregulation of PI3K-Akt signaling was independent of sex or duration of death-related tissue ischemia. Analysis of single nucleus RNA-seq of post-mortem skin tissue specifically identified the dermal fibroblast compartment to be most resilient as marked by adaptive induction of PI3K-Akt signaling. In addition, slow death also induced angiogenic pathways in the dermal endothelial cell compartment of postmortem human skin. In contrast, specific pathways supporting functional properties of the skin as an organ were downregulated following slow death. Such pathways included melanogenesis and those representing the skin extracellular matrix (collagen expression and metabolism). Efforts to understand the significance of death as a biological variable (DABV) in influencing the transcriptomic composition of surviving component tissues has far-reaching implications including rigorous interpretation of experimental data collected from the dead and mechanisms involved in transplant-tissue obtained from dead donors.
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4
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Dai J, Chen Y, Dai R, Jiang Y, Tian J, Liu S, Xu M, Li M, Zhou J, Liu C, Chen C. Agonal Factors Distort Gene-Expression Patterns in Human Postmortem Brains. Front Neurosci 2021; 15:614142. [PMID: 33841074 PMCID: PMC8027124 DOI: 10.3389/fnins.2021.614142] [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: 10/09/2020] [Accepted: 02/16/2021] [Indexed: 01/01/2023] Open
Abstract
Agonal factors, the conditions that occur just prior to death, can impact the molecular quality of postmortem brains, influencing gene expression results. Our study used gene expression data of 262 samples from ROSMAP with the detailed terminal state recorded for each donor, such as fever, infection, and unconsciousness. Fever and infection were the primary contributors to brain gene expression changes, brain cell-type-specific gene expression, and cell proportion changes. Furthermore, we also found that previous studies of gene expression in postmortem brains were confounded by agonal factors. Therefore, correction for agonal factors is important in the step of data preprocessing. Our analyses revealed fever and infection contributing to gene expression changes in postmortem brains and emphasized the necessity of study designs that document and account for agonal factors.
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Affiliation(s)
- Jiacheng Dai
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
- State Key Laboratory of Genetic Engineering, Human Phenome Institute, and School of Life Sciences, Fudan University, Shanghai, China
| | - Yu Chen
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Rujia Dai
- Upstate Medical University, Syracuse, NY, United States
| | - Yi Jiang
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jianghua Tian
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Sihan Liu
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Meng Xu
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Miao Li
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jiaqi Zhou
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Chunyu Liu
- Department of Psychiatry, Upstate Medical University, Syracuse, NY, United States
| | - Chao Chen
- Center for Medical Genetics, Department of Psychiatry, School of Life Sciences, National Clinical Research Center on Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
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5
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Sullivan K, Pantazopoulos H, Liebson E, Woo TUW, Baldessarini RJ, Hedreen J, Berretta S. What can we learn about brain donors? Use of clinical information in human postmortem brain research. HANDBOOK OF CLINICAL NEUROLOGY 2018; 150:181-196. [PMID: 29496141 DOI: 10.1016/b978-0-444-63639-3.00014-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Postmortem studies on the human brain reside at the core of investigations on neurologic and psychiatric disorders. Ground-breaking advances continue to be made on the pathologic basis of many of these disorders, at molecular, cellular, and neural connectivity levels. In parallel, there is increasing emphasis on improving methods to extract relevant demographic and clinical information about brain donors and, importantly, translate it into measures that can reliably and effectively be incorporated in the design and data analysis of postmortem human investigations. Here, we review the main source of information typically available to brain banks and provide examples on how this information can be processed. In particular, we discuss approaches to establish primary and secondary diagnoses, estimate exposure to therapeutic treatment and substance abuse, assess agonal status, and use time of death as a proxy in investigations on circadian rhythms. Although far from exhaustive, these considerations are intended as a contribution to ongoing efforts from tissue banks and investigators aimed at establishing robust, well-validated methods for collecting and standardizing information about brain donors, further strengthening the scientific rigor of human postmortem studies.
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Affiliation(s)
- Kathleen Sullivan
- Harvard Brain Tissue Resource Center, McLean Hospital, Belmont, MA, United States
| | - Harry Pantazopoulos
- Traslational Neuroscience Laboratory, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States
| | - Elizabeth Liebson
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States; Psychotic Disorders Division, McLean Hospital, Belmont, MA, United States
| | - T-U W Woo
- Harvard Brain Tissue Resource Center, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States; Laboratory of Cellular Neuropathology, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - Ross J Baldessarini
- Department of Psychiatry, Harvard Medical School, Boston, MA, United States; International Consortium for Psychotic and Bipolar Disorders Research, McLean Hospital, Belmont, MA, United States
| | - John Hedreen
- Harvard Brain Tissue Resource Center, McLean Hospital, Belmont, MA, United States
| | - Sabina Berretta
- Harvard Brain Tissue Resource Center, McLean Hospital, Belmont, MA, United States; Traslational Neuroscience Laboratory, McLean Hospital, Belmont, MA, United States; Department of Psychiatry, Harvard Medical School, Boston, MA, United States; Program in Neuroscience, Harvard Medical School, Boston, MA, United States.
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6
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Tunbridge EM, Eastwood SL, Harrison PJ. Changed relative to what? Housekeeping genes and normalization strategies in human brain gene expression studies. Biol Psychiatry 2011; 69:173-9. [PMID: 20673871 DOI: 10.1016/j.biopsych.2010.05.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/25/2010] [Accepted: 05/20/2010] [Indexed: 10/19/2022]
Abstract
Many studies in biological psychiatry compare the abundance of individual messenger RNAs between cases and control subjects or, more recently, between genotype groups. Most utilize some form of normalization procedure, usually expressing the transcript(s) of interest relative to that of a housekeeping gene or genes (also called reference genes), to overcome various sources of experimental error. Indeed, normalization is such a standard procedure that its purpose, principles, and limitations are sometimes overlooked, and some papers lack sufficient information as to its implementation. Here, we review the rationales for normalization and argue that in well-conducted psychiatric gene expression studies using human brain tissue, it is reducing intersubject variability rather than experimental error that is the major benefit of normalization. We also review the conceptual and empirical basis for the category of housekeeping genes-i.e., genes with a ubiquitous and invariant expression. We conclude that the evidence is against any such simple categorization and that a more pragmatic, less dogmatic, approach to the selection and implementation of reference genes is required, which takes into account the particular issues that pertain to human brain tissue studies. This pragmatism extends to the issue of whether normalization should be to one or multiple reference genes. We end by making several recommendations toward a more flexible, transparent, and comprehensive approach to data presentation and analysis. We illustrate the review with examples from studies of schizophrenia and mood disorder.
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Affiliation(s)
- Elizabeth M Tunbridge
- Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, United Kingdom
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7
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Papapetropoulos S, Shehadeh L, McCorquodale D. Optimizing human post-mortem brain tissue gene expression profiling in Parkinson's disease and other neurodegenerative disorders: from target "fishing" to translational breakthroughs. J Neurosci Res 2008; 85:3013-24. [PMID: 17503538 DOI: 10.1002/jnr.21355] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Insights on the etiopathogenesis of common neurodegenerative disorders such as Parkinson's disease (PD) and Alzheimer's disease (AD) have been largely based on the discovery of gene mutations in genetically determined forms. Although these discoveries have been helpful in elucidating the basic molecular pathogenesis of familial forms, they represent a small fraction of cases, leaving the large majority classified as idiopathic. In the postgenomic era, brain tissue gene expression profiling has allowed relative quantitative assessment of thousands of genes simultaneously from one tissue sample, providing clues for novel candidate genes and processes implicated in neurodegenerative disorders. Some remain critical of "fishing expedition" science, but gene expression profiling is a discovery-based procedure well suited for the study of largely idiopathic and multifactorial diseases. However, the technology is still under development, and many methodological and biological aspects contribute to the heterogeneous results obtained from gene expression profiling. In this Review, we discuss the advantages and limitations of this technology in simple terms and identify the key variables that influence/limit gene expression profiling-derived translational breakthroughs in neurodegenerative diseases.
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Affiliation(s)
- Spiridon Papapetropoulos
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
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8
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Papapetropoulos S, McCorquodale D. Gene-expression profiling in Parkinson’s disease: discovery of valid biomarkers, molecular targets and biochemical pathways. FUTURE NEUROLOGY 2007. [DOI: 10.2217/14796708.2.1.29] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the past decade, several gene mutations have been described in families with a Mendelian inheritance pattern of Parkinson’s disease (PD), using linkage mapping. These cases represent only a small percentage (<5%) of the patients who develop PD. The current understanding of the mechanisms that underlie aspects of the neurodegenerative process of PD is based mainly on research of functional pathways related to these genes. However, even with knowledge of these pathways, the number of relevant genes may still be very large. In the post-genomic era, seven high-throughput gene array studies have attempted to identify candidate genes and biochemical pathways in PD. In this review, results from these studies and different factors influencing optimal target and biomarker discovery with gene-expression profiling are discussed.
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Affiliation(s)
- Spiridon Papapetropoulos
- University of Miami, Department of Neurology, Miller School of Medicine, 1501 NW 9th Avenue (NPF), Room 4004, Miami, FL 33136, USA
| | - Donald McCorquodale
- University of Miami, Department of Neurology, Miller School of Medicine, 1501 NW 9th Avenue (NPF), Room 4004, Miami, FL 33136, USA
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9
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Abstract
Development and implementation of microarray techniques to quantify expression levels of dozens to hundreds to thousands of transcripts simultaneously within select tissue samples from normal control subjects and neurodegenerative diseased brains has enabled scientists to create molecular fingerprints of vulnerable neuronal populations in Alzheimer's disease (AD) and related disorders. A goal is to sample gene expression from homogeneous cell types within a defined region without potential contamination by expression profiles of adjacent neuronal subpopulations and nonneuronal cells. The precise resolution afforded by single cell and population cell RNA analysis in combination with microarrays and real-time quantitative polymerase chain reaction (qPCR)-based analyses allows for relative gene expression level comparisons across cell types under different experimental conditions and disease progression. The ability to analyze single cells is an important distinction from global and regional assessments of mRNA expression and can be applied to optimally prepared tissues from animal models of neurodegeneration as well as postmortem human brain tissues. Gene expression analysis in postmortem AD brain regions including the hippocampal formation and neocortex reveals selectively vulnerable cell types share putative pathogenetic alterations in common classes of transcripts, for example, markers of glutamatergic neurotransmission, synaptic-related markers, protein phosphatases and kinases, and neurotrophins/neurotrophin receptors. Expression profiles of vulnerable regions and neurons may reveal important clues toward the understanding of the molecular pathogenesis of various neurological diseases and aid in identifying rational targets toward pharmacotherapeutic interventions for progressive, late-onset neurodegenerative disorders such as mild cognitive impairment (MCI) and AD.
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Affiliation(s)
- Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA.
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10
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Woulfe JM, Hammond R, Richardson B, Sooriabalan D, Parks W, Rippstein P, Munoz DG. Reduction of neuronal intranuclear rodlets immunoreactive for tubulin and glucocorticoid receptor in Alzheimer's disease. Brain Pathol 2006; 12:300-7. [PMID: 12146798 PMCID: PMC8095929 DOI: 10.1111/j.1750-3639.2002.tb00444.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Neuronal intranuclear rodlets were described in normal brain over a century ago, but their functional significance and pathological relevance is unknown. Here, we show co-localization of tubulin and glucocorticoid receptor-like immunoreactivity in these intranuclear inclusions in human brain. In addition, we provide evidence for a massive reduction in their areal density in Alzheimer's disease brain, but not in another common neurodegenerative condition, dementia with Lewy bodies. The marked reduction of these inclusions in Alzheimer's disease may support the concept of a role for stress hormones in Alzheimer's pathogenesis.
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Affiliation(s)
- John M Woulfe
- Department of Pathology and Laboratory Medicine, The University of Ottawa, The Ottawa Hospital, Ontario, Canada.
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11
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Neuronal gene expression profiling: uncovering the molecular biology of neurodegenerative disease. PROGRESS IN BRAIN RESEARCH 2006; 158:197-222. [PMID: 17027698 DOI: 10.1016/s0079-6123(06)58010-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The development of gene array techniques to quantify expression levels of dozens to thousands of genes simultaneously within selected tissue samples from control and diseased brain has enabled researchers to generate expression profiles of vulnerable neuronal populations in several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, schizophrenia, multiple sclerosis, and Creutzfeld-Jakob disease. Intriguingly, gene expression analysis reveals that vulnerable brain regions in many of these diseases share putative pathogenetic alterations in common classes of genes, including decrements in synaptic transcript levels and increments in immune response transcripts. Thus, gene expression profiles of diseased neuronal populations may reveal mechanistic clues to the molecular pathogenesis underlying various neurological diseases and aid in identifying potential therapeutic targets. This chapter will review how regional and single cell gene array technologies have advanced our understanding of the genetics of human neurological disease.
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12
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Tomita H, Vawter MP, Walsh DM, Evans SJ, Choudary PV, Li J, Overman KM, Atz ME, Myers RM, Jones EG, Watson SJ, Akil H, Bunney WE. Effect of agonal and postmortem factors on gene expression profile: quality control in microarray analyses of postmortem human brain. Biol Psychiatry 2004; 55:346-52. [PMID: 14960286 PMCID: PMC3098566 DOI: 10.1016/j.biopsych.2003.10.013] [Citation(s) in RCA: 258] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Revised: 10/21/2003] [Accepted: 10/21/2003] [Indexed: 11/17/2022]
Abstract
There are major concerns that specific agonal conditions, including coma and hypoxia, might affect ribonucleic acid (RNA) integrity in postmortem brain studies. We report that agonal factors significantly affect RNA integrity and have a major impact on gene expression profiles in microarrays. In contrast to agonal factors, gender, age, and postmortem factors have less effect on gene expression profiles. The Average Correlation Index is proposed as a method for evaluating RNA integrity on the basis of similarity of microarray profiles. Reducing the variance due to agonal factors is critical in investigating small but validated gene expression differences in messenger RNA levels between psychiatric patients and control subjects.
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Affiliation(s)
- Hiroaki Tomita
- Department of Psychiatry and Human Behavior, University of California-Irvine, Irvine, CA 92697-1675, USA
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13
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Husseman JW, Hallows JL, Bregman DB, Leverenz JB, Nochlin D, Jin LW, Vincent I. Hyperphosphorylation of RNA polymerase II and reduced neuronal RNA levels precede neurofibrillary tangles in Alzheimer disease. J Neuropathol Exp Neurol 2001; 60:1219-32. [PMID: 11764094 DOI: 10.1093/jnen/60.12.1219] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Affected neurons of Alzheimer disease (AD) brain are distinguished by the presence of the cell cycle cdc2 kinase and mitotic phosphoepitopes. A significant body of previous data has documented a decrease in neuronal RNA levels and nucleolar volume in AD brain. Here we present evidence that integrates these seemingly distinct findings and offers an explanation for the degenerative outcome of the disease. During mitosis cdc2 phosphorylates and inhibits the major transcriptional regulator RNA polymerase II (RNAP II). We therefore investigated cdc2 phosphorylation of RNAP II in AD brain. Using the H5 and H14 monoclonal antibodies specific for the cdc2-phosphorylated sites in RNAP II, we found that the polymerase is highly phosphorylated in AD. Moreover, RNAP II in AD translocates from its normally nuclear compartment to the cytoplasm of affected neurons, where it colocalizes with cdc2. These M phase-like changes in RNAP II correlate with decreased levels of poly-A RNA in affected neurons. Significantly, they precede tau phosphorylation and neurofibrillary tangle formation. Our data support the hypothesis that inappropriate activation of the cell cycle cdc2 kinase in differentiated neurons contributes to neuronal dysfunction and degeneration in part by inhibiting RNAP II and cellular processes dependent on transcription.
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Affiliation(s)
- J W Husseman
- Department of Pathology and the Nathan Shock Center of Excellence for Biology of Aging, University of Washington, Seattle 98195, USA
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14
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Ginsberg SD, Hemby SE, Lee VMY, Eberwine JH, Trojanowski JQ. Expression profile of transcripts in Alzheimer's disease tangle-bearing CA1 neurons. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200007)48:1<77::aid-ana12>3.0.co;2-a] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Heffernan JM, Eastwood SL, Nagy Z, Sanders MW, McDonald B, Harrison PJ. Temporal cortex synaptophysin mRNA is reduced in Alzheimer's disease and is negatively correlated with the severity of dementia. Exp Neurol 1998; 150:235-9. [PMID: 9527892 DOI: 10.1006/exnr.1997.6772] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We measured synaptophysin mRNA in neocortical tissue from 7 prospectively assessed, pathologically verified normal individuals, 17 subjects with Alzheimer's disease (AD), and 13 subjects with a non-AD dementia. In temporal cortex (Brodmann area 21), synaptophysin mRNA was decreased in AD and non-AD dementia groups compared to controls. The loss was also present relative to polyadenylated mRNA content. Synaptophysin mRNA signal correlated negatively with the degree of dementia and negatively with the pathological severity of AD. In occipital cortex (Brodmann area 17) there were no differences between groups nor clinicopathological correlations. These data extend the evidence for a regional synaptic pathology in AD which affects synaptic protein gene expression by temporal cortex neurons.
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Affiliation(s)
- J M Heffernan
- Department of Clinical Neurology (Neuropathology), Warneford Hospital, Warneford Lane, Oxford, OX3 7JX, United Kingdom
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16
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Thomas GJ, Harper CG, Dodd PR. Expression of GABA(A) receptor isoform genes in the cerebral cortex of cirrhotic and alcoholic cases assessed by S1 nuclease protection assays. Neurochem Int 1998; 32:375-85. [PMID: 9596562 DOI: 10.1016/s0197-0186(97)00102-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pathogenic processes underlying the localized reduction in neuronal number in cerebral cortex in human alcoholics have been reported to be associated with selective variations in the parameters of GABA(A) receptor site binding. Since the properties of the receptor complex depend on its isoform composition, we studied how the expression of GABA(A) receptor subunit isoform genes varied with alcoholism. Cerebral cortex tissue was obtained at autopsy from chronic human alcoholics (average ethanol intake > 80 g/day for most of their adult lives; n = 17) and matched controls (< 20 g/day ethanol; n = 15). Eight of the alcoholics and five of the controls had pathologically confirmed cirrhosis of the liver. Expression of alpha1, alpha2, alpha3, alpha5, beta1, beta3, and gamma2 GABA(A) mRNA was assessed by S1 nuclease protection assays. After phosphorimager quantitation and normalization to GAPDH mRNA and 18S rRNA, none of the mRNA species showed significantly different expression in uncomplicated alcoholics. Analysis of differences in the patterns of expression of the various subunits showed the alpha1 signal was strongest in combined cirrhotic motor cortex while the alpha3 and beta3 values were greatest in combined cirrhotic frontal cortex. It appears that only major differences in mRNA expression may be detected by this technique in human brain.
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Affiliation(s)
- G J Thomas
- Clinical Research Laboratory, Royal Brisbane Hospital Research Foundation, Australia
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17
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Amoureux MC, Van Gool D, Herrero MT, Dom R, Colpaert FC, Pauwels PJ. Regulation of metallothionein-III (GIF) mRNA in the brain of patients with Alzheimer disease is not impaired. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1997; 32:101-21. [PMID: 9437661 DOI: 10.1007/bf02815170] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Contradictory results have been reported on the downregulation and role of the brain-specific protein metallothionein-III (MT-III, GIF) in Alzheimer disease (AD). In this article, the importance of MT-III downregulation in AD brain was re-evaluated in temporal and frontal cortex, hippocampus, and cerebellum of 11 AD patients and two groups of five and six control subjects, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the levels of MT-III mRNA relative to the levels of three constitutive RNAs: beta-actin, glyceraldehyde-3-phosphate dehydrogenase (G3PDH), and ribosomal RNA 18S (rRNA 18S). The distribution of MT-III was similar to that of each of the three constitutive RNAs. The relative levels of each of these RNAs was high in brain regions examined in both AD patients and control subjects. Our findings do not support a downregulation of MT-III mRNA in the frontal cortex as well as the temporal cortex and hippocampus of AD patients. However, the level of MT-III mRNA was not constant in the investigated samples, suggesting that MT-III mRNA regulation could be controlled by factors other than AD pathology. Brain-derived neurotrophic factor (BDNF) mRNA levels were hardly detectable by RT-PCR in human brain tissue; a trend for a decrease was apparent in the temporal cortex of AD patients. In conclusion, the content of MT-III mRNA in the brain of AD patients was not detectably impaired, whereas BDNF mRNA may be affected.
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Affiliation(s)
- M C Amoureux
- Laboratory of Cellular and Molecular Neurobiology, Centre de Recherche Pierre Fabre, Castres, France
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Harrison PJ, Burnet PW, Falkai P, Bogerts B, Eastwood SL. Gene expression and neuronal activity in schizophrenia: a study of polyadenylated mRNA in the hippocampal formation and cerebral cortex. Schizophr Res 1997; 26:93-102. [PMID: 9323338 DOI: 10.1016/s0920-9964(97)00048-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The abundance of polyadenylated messenger RNA (poly(A)+mRNA) reflects overall gene expression and provides an index on neuronal activity. Poly(A)+mRNA was measured in the hippocampal formation and in occipital, temporal, cingulate and frontal cortices (Brodmann areas 17, 22, 24 and 46, respectively) of 11 schizophrenic and 17 control subjects post mortem by in situ hybridization histochemistry with a 35S-oligodeoxythymidine probe. There were no differences in poly(A)+mRNA between cases and controls, except for a modest decrease in the parahippocampal gyrus of the schizophrenics which may be attributable to cytoarchitectural differences in this area in the disease. The unchanged level of poly(A)+mRNA in all other regions argues against the existence of a widespread or sustained alteration in the metabolic activity of cortical neurons in schizophrenia. It also provides a further indication that the differential expression of individual transcripts reported in the disease is not merely reflecting changes in overall gene expression.
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Affiliation(s)
- P J Harrison
- Department of Psychiatry, Warneford Hospital, University of Oxford, UK.
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19
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Fahnestock M, Scott SA, Jetté N, Weingartner JA, Crutcher KA. Nerve growth factor mRNA and protein levels measured in the same tissue from normal and Alzheimer's disease parietal cortex. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1996; 42:175-8. [PMID: 8915599 DOI: 10.1016/s0169-328x(96)00193-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nerve growth factor (NGF) mRNA and protein levels were determined in parietal cortex samples from both normal and Alzheimer's disease (AD) patients. NGF protein levels were slightly elevated in AD patients compared to controls, but NGF mRNA levels were unchanged in the same tissue samples. Thus, small but reproducible increases in NGF protein reported in AD cortex do not result from increases in NGF mRNA.
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Affiliation(s)
- M Fahnestock
- Department of Biomedical Sciences, McMaster University, Hamilton, Ont., Canada.
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20
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Harrison PJ, Heath PR, Eastwood SL, Burnet PW, McDonald B, Pearson RC. The relative importance of premortem acidosis and postmortem interval for human brain gene expression studies: selective mRNA vulnerability and comparison with their encoded proteins. Neurosci Lett 1995; 200:151-4. [PMID: 9064599 DOI: 10.1016/0304-3940(95)12102-a] [Citation(s) in RCA: 275] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To help account for the variable quality and quantity of RNA in human brain, we have studied the effect of premortem (agonal state) and postmortem factors on the detection of poly(A)+mRNA and eight mRNAs. For comparison, the influence of the same factors upon gene products encoded by the mRNAs was studied immunocytochemically or by receptor autoradiography. Brain pH declined with increasing age at death and was related to agonal state severity, but was independent of postmortem interval and the histological presence of hypoxic changes. By linear regression, pH was significantly associated with the abundance of several of the RNAs, but not with poly(A)+mRNA, immunoreactivities, or binding site densities. Postmortem interval had a limited influence upon mRNA and protein products. Freezer storage time showed no effect. Parallel rat brain studies showed no relationship between postmortem interval (0-48 h) and amounts of total RNA, poly(A)+RNA, or two individual mRNAs; however, RNA content was reduced by 40% at 96 h after death. pH is superior to clinical assessments of agonal state or mode of death in predicting mRNA preservation. It provides a simple means to improve human brain gene expression studies. pH is stable after death and during freezer storage and can be measured either in cerebrospinal fluid or in homogenised tissue.
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Affiliation(s)
- P J Harrison
- Department of Psychiatry, University of Oxford, UK
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21
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Eastwood SL, McDonald B, Burnet PW, Beckwith JP, Kerwin RW, Harrison PJ. Decreased expression of mRNAs encoding non-NMDA glutamate receptors GluR1 and GluR2 in medial temporal lobe neurons in schizophrenia. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1995; 29:211-23. [PMID: 7609609 DOI: 10.1016/0169-328x(94)00247-c] [Citation(s) in RCA: 164] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Schizophrenia is associated with a complex pattern of alterations in the glutamatergic system of the brain. Previous studies have shown a reduced density of some hippocampal non-N-methyl-D-aspartate (non-NMDA) receptors which is accompanied by a loss of encoding receptor mRNA. We have extended this work using in situ hybridization histochemistry with oligonucleotide probes specific for two non-NMDA receptor transcripts, GluR1 and GluR2, in right and left medial temporal lobe sections from 9 schizophrenics and 14 matched normal controls. Both mRNAs were found to be decreased bilaterally and to a similar degree in the hippocampal formation in schizophrenia. Analysis of autoradiograms showed a regional loss of GluR1 and GluR2 mRNAs in dentate gyrus, CA4, CA3 and subiculum. GluR2 mRNA was also reduced in parahippocampal gyrus. These reductions ranged from 25% to 70% in terms of 35S nCi/g tissue equivalents. Additionally we measured grain density for the mRNAs over individual pyramidal neurons in each area. GluR1 and GluR2 mRNAs were less abundant per neuron in CA4 and CA3 in schizophrenia than in controls. GluR2 mRNA was also reduced significantly in parahippocampal gyrus neurons, with an increase in the proportion of GluR1 mRNA to GluR2 mRNA in this cell population. No asymmetries in expression of GluR1 and GluR2 were found in normal or schizophrenic brains. These data further the evidence for reduced non-NMDA receptor expression in the medial temporal lobe in schizophrenia. They confirm the decrease in GluR1 mRNA and show that there are similar losses of GluR2 mRNA in the hippocampal formation. The pattern of changes in the two mRNAs suggests a common mechanism which is unknown but which may be a correlate of the neurodevelopmental abnormalities postulated to underlie the disease. The reduction of GluR2 mRNA but not GluR1 mRNA in parahippocampal gyrus neurons in schizophrenia may have functional consequences given the calcium permeability of non-NMDA receptors lacking the GluR2 subunit.
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Affiliation(s)
- S L Eastwood
- University Department of Psychiatry, Warneford Hospital, Oxford, UK
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Jetté N, Cole MS, Fahnestock M. NGF mRNA is not decreased in frontal cortex from Alzheimer's disease patients. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1994; 25:242-50. [PMID: 7808223 DOI: 10.1016/0169-328x(94)90159-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Alzheimer's disease (AD) is characterized by neuronal dysfunction and degeneration in certain brain regions such as cortex, hippocampus and basal forebrain. Specific neurochemical defects such as decreases in cholinergic enzymes and in the amounts of mRNA in AD brain have also been reported. Nerve growth factor (NGF), a protein necessary for the development, regulation and survival of basal forebrain cholinergic neurons (BFCN), is synthesized in target areas of BFCN (cortex, hippocampus) and is supplied to BFCN by retrograde transport. Thus, NGF is under investigation both as a potential therapeutic agent and for its possible involvement in the pathogenesis of AD. In this study, postmortem brain tissues from both control and AD cases were investigated for amounts of poly (A)+ mRNA and NGF mRNA in the frontal cortex, a region rich in cholinergic afferents. Yields of poly(A)+ mRNA were similar from normal and AD tissues. Human NGF mRNA comigrated with murine NGF mRNA on Northern blots. Additionally, dot blot quantitation demonstrated that NGF mRNA levels do not differ in the inferior frontal gyrus of normal and AD patients. Thus, we conclude that levels of mRNA in general, and of NGF mRNA in particular, are unchanged in the frontal cortex of individuals affected by AD.
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Affiliation(s)
- N Jetté
- Department of Biomedical Sciences, McMaster University, Hamilton, Ont., Canada
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Pardue S, White CL, Bigio EH, Morrison-Bogorad M. Anomalous binding of radiolabeled oligonucleotide probes to plaques and tangles in Alzheimer disease hippocampus. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1994; 22:1-24. [PMID: 7916765 DOI: 10.1007/bf03160091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Several reports indicate that Alzheimer disease (AD) brain contains elevated levels of heat shock 70 proteins. To determine the cellular localization of the heat shock 70 mRNAs, specific oligonucleotide probes were in situ hybridized to AD and control brains. When oligonucleotides were in situ hybridized to brain sections with no AD neuropathology, hybridization was cell-specific and prior ribonuclease (RNase) treatment of adjacent sections resulted in no hybridization signal. However, in situ hybridization to AD hippocampus resulted in heavy grain deposition over senile plaques and neurofibrillary tangles. Despite altering a number of experimental variables, we observed a similar pattern of grain deposition with most of the oligonucleotides tested, including one oligonucleotide specific for glutamic acid decarboxylase mRNA. In situ hybridization with either an RNA probe for glutamic acid decarboxylase or an oligonucleotide probe specific for 18S rRNA did not show this pattern of grain deposition. In control studies a sense hsc70 oligonucleotide showed no grain deposition in either cerebellum or hippocampus. Sections from AD hippocampus pretreated with RNase prior to in situ hybridization demonstrated enhanced grain deposition with the majority of probes tested. Anomalous in situ hybridization to AD hippocampus was usually eliminated by removing formamide from the posthybridization washes, although post-RNase sticking often remained intense. These findings indicate that artifactual probe binding to senile plaques and neurofibrillary tangles may complicate the analysis of in situ hybridization studies using oligonucleotide probes to determine mRNA distribution in AD brain.
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Affiliation(s)
- S Pardue
- Department of Neurology, University of Texas Southwestern Medical Center at Dallas 75235-9115
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Callahan LM, Selski DJ, Martzen MR, Cheetham JE, Coleman PD. Preliminary evidence: decreased GAP-43 message in tangle-bearing neurons relative to adjacent tangle-free neurons in Alzheimer's disease parahippocampal gyrus. Neurobiol Aging 1994; 15:381-6. [PMID: 7936069 DOI: 10.1016/0197-4580(94)90041-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Loss of synapses has been shown to correlate with the severity of dementia in Alzheimer's disease (AD). Intracellular neurofibrillary tangles (NFTs) have also been shown to correlate to the severity of AD dementia. We have been investigating the influence of NFTs on mRNAs related to neuronal plasticity and synaptic function. We recently reported a decrease in message for the plasticity marker, GAP-43, in AD cases with high tangle densities. The study did not permit us to determine if: a) the decrease in GAP-43 message was specific to the NFT-bearing neurons, b) a general decrease in GAP-43 message was occurring in all surviving neurons, or c) the decrease in GAP-43 message was due to a loss of neurons. It is unlikely a loss of neurons could explain the sixfold GAP-43 message loss we reported, because only a 19% excess decrease in density of hippocampal neurons occurs in AD cases with high tangle densities. Consequently, the study reported here was undertaken to determine if a general decrease in GAP-43 message was occurring in all surviving AD neurons or if the decrease in GAP-43 message was specific to NFT-bearing neurons. We combined immunocytochemistry for neurofibrillary tangles with in situ hybridization for GAP-43 message. We report here preliminary evidence indicating a decrease in GAP-43 message in NFT-bearing neurons compared to adjacent nontangle bearing neurons in parahippocampal cortex of AD patients.
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Affiliation(s)
- L M Callahan
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, NY 14642
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Eastwood SL, Burnet PW, McDonald B, Clinton J, Harrison PJ. Synaptophysin gene expression in human brain: a quantitative in situ hybridization and immunocytochemical study. Neuroscience 1994; 59:881-92. [PMID: 8058126 DOI: 10.1016/0306-4522(94)90292-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Synaptophysin is a presynaptic vesicle protein. Its quantitative detection has become established as a molecular marker of synaptic density. We have studied synaptophysin messenger RNA in the neocortex, hippocampus and cerebellum using in situ hybridization histochemistry to see if the encoding transcript can be detected in post mortem human brain and to investigate factors which might influence its abundance. Synaptophysin was also measured immunocytochemically in the hippocampus. The level of synaptophysin messenger RNA expression was uniform in all neocortical areas examined. Strong correlations were found for the amount of synaptophysin messenger RNA between individual regions and between homologous areas in the two hemispheres. Synaptophysin messenger RNA declined with increasing age and prolonged post mortem interval. Synaptophysin immunoreactivity also reduced with age, as well as with duration of formalin fixation but not post mortem interval. Synaptophysin immunoreactivity correlated with the abundance of the messenger RNA in neurons within, and projecting to, each hippocampal subfield. Significantly greater synaptophysin immunoreactivity was seen in the left than the right CA4 and CA1 regions. These data show that quantitative detection of synaptophysin messenger RNA as well as synaptophysin itself can reliably be carried out in post mortem human brain sections. They are in keeping with other findings that synaptic density is relatively uniform through the neocortex and decreases with age. They also suggest a possible asymmetry of hippocampal synaptophysin expression. The level of synaptophysin messenger RNA paralleled that of synaptophysin immunoreactivity, indicating that changes in gene expression contribute to variations in the latter observed in aging and other situations. Detection of synaptophysin messenger RNA broadens the range of methods by which synaptic protein gene products can be studied and used as markers of synaptic density and synaptic involvement during physiological and pathological processes in human brain.
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Affiliation(s)
- S L Eastwood
- University Department of Psychiatry, Warneford Hospital, Oxford, U.K
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Abstract
Many potentially valuable techniques for the understanding of human neurobiological and neuropathological processes require the use of RNA obtained from postmortem tissue. As with earlier neurochemical studies, there are two particular problems posed by such tissue in comparison with tissue from experimental animals. These are the postmortem interval and the condition of the patient prior to death, referred to as the agonal state. We review the nature and extent of the effects of postmortem interval and agonal state on RNA in brain tissue, with particular reference to the study of neuropsychiatric disorders. Perhaps surprisingly, postmortem interval has at most a modest effect on RNA. Abundant intact and biologically active RNA is present in tissue frozen 36 h or more after death. Postmortem interval does not account for the marked variability observed among human brains in all RNA parameters. Despite the overall stability of RNA after death, some evidence suggests that individual RNAs may undergo postmortem decay. Less attention has been paid to the effects of agonal state. The existing data indicate that events in the premortem period such as hypoxia and coma can affect the amount of some messenger RNAs. The nature of agonal state influences depends on the messenger RNA in question, though the basis for this selective vulnerability is unknown. No agonal state effect on overall RNA level or activity has been found. The data show that postmortem brain tissue can be used for RNA research. However, considerable attention must be paid to controlling for the influences of pre- and postmortem factors, especially when quantitative analyses are performed.
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Affiliation(s)
- A J Barton
- Department of Biomedical Science, The University, Sheffield, England
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Harrison PJ, Procter AW, Exworthy T, Roberts GW, Najlerahim A, Barton AJ, Pearson RC. Heat shock protein (hsx70) mRNA expression in human brain: effects of neurodegenerative disease and agonal state. Neuropathol Appl Neurobiol 1993; 19:10-21. [PMID: 8386339 DOI: 10.1111/j.1365-2990.1993.tb00400.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Heat shock proteins (hsps) are involved in the response by cells to stress including hyperthermia, hypoxia and injury. Previous work has demonstrated expression of messenger RNA (mRNA) encoding 70 kDa hsps (hsp70) in animal brain in response to stimuli such as these. We have used in situ hybridization histochemistry to assess the distribution and quantity of a specific hsp70 (called hsx70) mRNA in frontal cortex and cerebellum from normal and demented patients whose pre-mortem course had been documented. In cortex, hsx70 mRNA was concentrated over pia mater and glia but was also present over neurons; in cerebellum, hsx70 mRNA was prominent over granule cells but absent from Purkinje cells. Detection of hsx70 mRNA did not correlate with pre-mortem factors such as pyrexia or coma. Increased hsx70 mRNA was found in frontal cortex white matter in Alzheimer's disease and in a mixed group of other neurodegenerative disorders. No changes occurred in cerebellum. The data provide further evidence for altered hsp gene expression in dementia, and support the existence of a stress response occurring in brains affected by such diseases.
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Harrison PJ, Barton AJ, McDonald B, Pearson RC. Alzheimer's disease: specific increases in a G protein subunit (Gs alpha) mRNA in hippocampal and cortical neurons. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1991; 10:71-81. [PMID: 1647485 DOI: 10.1016/0169-328x(91)90058-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The GTP binding protein, Gs, activates adenyl cyclase in direct response to stimulation of several neurotransmitter receptors. In situ hybridization histochemistry (ISHH) with a 35S-labelled oligonucleotide has been used to detect the mRNA encoding the alpha subunit of Gs (Gs alpha) in human hippocampus, temporal and visual cortices and cerebellum, and its level has been compared between Alzheimer's disease (AD) and control brains. A marked regional increase was found in the hippocampus of AD cases. Analysis of levels of Gs alpha mRNA in individual constituent pyramidal cells confirmed this increase (3 to 4-fold in densitometric units) in hippocampal fields CA1, CA3 and CA4, as well as in temporal cortex. Levels of Gs alpha mRNA were also determined relative to total poly(A)+ mRNA in the same cell populations in each case. Gene-specific elevation of Gs alpha mRNA was thereby confirmed in hippocampal fields, and also in temporal cortex. No changes were seen in visual cortex. The increase in Gs alpha mRNA may represent a response by AD neurons in affected areas to receptor alterations, or to an abnormality in receptor-G protein coupling. Alternatively, altered G protein gene expression might be a pathogenic event underlying changes in linked receptor populations.
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Affiliation(s)
- P J Harrison
- Department of Anatomy, St. Mary's Hospital Medical School, London U.K
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