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Zimmermann M. Neuronal AChE splice variants and their non-hydrolytic functions: redefining a target of AChE inhibitors? Br J Pharmacol 2014; 170:953-67. [PMID: 23991627 DOI: 10.1111/bph.12359] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 08/04/2013] [Accepted: 08/12/2013] [Indexed: 12/11/2022] Open
Abstract
AChE enzymatic inhibition is a core focus of pharmacological intervention in Alzheimer's disease (AD). Yet, AChE has also been ascribed non-hydrolytic functions, which seem related to its appearance in various isoforms. Neuronal AChE presents as a tailed form (AChE-T) predominantly found on the neuronal synapse, and a facultatively expressed readthough form (AChE-R), which exerts short to medium-term protective effects. Notably, this latter form is also found in the periphery. While these non-hydrolytic functions of AChE are most controversially discussed, there is evidence for them being additional targets of AChE inhibitors. This review aims to provide clarification as to the role of these AChE splice variants and their interplay with other cholinergic parameters and their being targets of AChE inhibition: AChE-R is particularly involved in the mediation of (anti-)apoptotic events in cholinergic cells, involving adaptation of various cholinergic parameters and a time-dependent link to the expression of neuroprotective factors. The AChE-T C-terminus is central to AChE activity regulation, while isolated AChE-T C-terminal fragments mediate toxic effects via the α7 nicotinic acetylcholine receptor. There is direct evidence for roles of AChE-T and AChE-R in neurodegeneration and neuroprotection, with these roles involving AChE as a key modulator of the cholinergic system: in vivo data further encourages the use of AChE inhibitors in the treatment of neurodegenerative conditions such as AD since effects on both enzymatic activity and the enzyme's non-hydrolytic functions can be postulated. It also suggests that novel AChE inhibitors should enhance protective AChE-R, while avoiding the concomitant up-regulation of AChE-T.
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Affiliation(s)
- M Zimmermann
- Department of Pharmacology, School of Pharmacy, Goethe University Frankfurt, Frankfurt am Main, Germany
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Uversky VN. Wrecked regulation of intrinsically disordered proteins in diseases: pathogenicity of deregulated regulators. Front Mol Biosci 2014; 1:6. [PMID: 25988147 PMCID: PMC4428494 DOI: 10.3389/fmolb.2014.00006] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/06/2014] [Indexed: 12/14/2022] Open
Abstract
Biologically active proteins without stable tertiary structure are common in all known proteomes. Functions of these intrinsically disordered proteins (IDPs) are typically related to regulation, signaling, and control. Cellular levels of these important regulators are tightly regulated by a variety mechanisms ranging from firmly controlled expression to precisely targeted degradation. Functions of IDPs are controlled by binding to specific partners, alternative splicing, and posttranslational modifications among other means. In the norm, right amounts of precisely activated IDPs have to be present in right time at right places. Wrecked regulation brings havoc to the ordered world of disordered proteins, leading to protein misfolding, misidentification, and missignaling that give rise to numerous human diseases, such as cancer, cardiovascular disease, neurodegenerative diseases, and diabetes. Among factors inducing pathogenic transformations of IDPs are various cellular mechanisms, such as chromosomal translocations, damaged splicing, altered expression, frustrated posttranslational modifications, aberrant proteolytic degradation, and defective trafficking. This review presents some of the aspects of deregulated regulation of IDPs leading to human diseases.
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Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida Tampa, FL, USA ; Biology Department, Faculty of Science, King Abdulaziz University Jeddah, Saudi Arabia ; Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences Moscow, Russia
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Affiliation(s)
- Johnny Habchi
- Aix-Marseille Université , Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 7257, 13288, Marseille, France
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La Cognata V, Iemmolo R, D'Agata V, Scuderi S, Drago F, Zappia M, Cavallaro S. Increasing the Coding Potential of Genomes Through Alternative Splicing: The Case of PARK2 Gene. Curr Genomics 2014; 15:203-16. [PMID: 24955028 PMCID: PMC4064560 DOI: 10.2174/1389202915666140426003342] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 04/05/2014] [Accepted: 04/23/2014] [Indexed: 01/28/2023] Open
Abstract
The completion of the Human Genome Project aroused renewed interest in alternative splicing, an efficient and widespread mechanism that generates multiple protein isoforms from individual genes. Although our knowledge about alternative splicing is growing exponentially, its real impact on cellular life is still to be clarified. Connecting all splicing features (genes, splice transcripts, isoforms, and relative functions) may be useful to resolve this tangle. Herein, we will start from the case of a single gene, Parkinson protein 2, E3 ubiquitin protein ligase (PARK2), one of the largest in our genome. This gene is implicated in the pathogenesis of autosomal recessive juvenile Parkinsonism and it has been recently linked to cancer, leprosy, autism, type 2 diabetes mellitus and Alzheimer’s disease. PARK2 primary transcript undergoes an extensive alternative splicing, which enhances transcriptomic diversification and protein diversity in tissues and cells. This review will provide an update of all human PARK2 alternative splice transcripts and isoforms presently known, and correlate them to those in rat and mouse, two common animal models for studying human disease genes. Alternative splicing relies upon a complex process that could be easily altered by both cis and trans-acting mutations. Although the contribution of PARK2 splicing in human disease remains to be fully explored, some evidences show disruption of this versatile form of genetic regulation may have pathological consequences.
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Affiliation(s)
- Valentina La Cognata
- 1Functional Genomics Center, Institute of Neurological Sciences, Italian National Research Council, Via Paolo Gaifami 18, 95125, Catania, Italy
| | - Rosario Iemmolo
- 1Functional Genomics Center, Institute of Neurological Sciences, Italian National Research Council, Via Paolo Gaifami 18, 95125, Catania, Italy
| | - Velia D'Agata
- 2Department of Bio-Medical Sciences, Section of Anatomy and Histology, University of Catania, Italy
| | - Soraya Scuderi
- 2Department of Bio-Medical Sciences, Section of Anatomy and Histology, University of Catania, Italy
| | - Filippo Drago
- 3Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, University of Catania, Italy
| | - Mario Zappia
- 4Department "G.F. Ingrassia", Section of Neuroscience, University of Catania, Italy
| | - Sebastiano Cavallaro
- 1Functional Genomics Center, Institute of Neurological Sciences, Italian National Research Council, Via Paolo Gaifami 18, 95125, Catania, Italy
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Hales CM, Seyfried NT, Dammer EB, Duong D, Yi H, Gearing M, Troncoso JC, Mufson EJ, Thambisetty M, Levey AI, Lah JJ. U1 small nuclear ribonucleoproteins (snRNPs) aggregate in Alzheimer's disease due to autosomal dominant genetic mutations and trisomy 21. Mol Neurodegener 2014; 9:15. [PMID: 24773620 PMCID: PMC4022210 DOI: 10.1186/1750-1326-9-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/18/2014] [Indexed: 01/08/2023] Open
Abstract
Background We recently identified U1 small nuclear ribonucleoprotein (snRNP) tangle-like aggregates and RNA splicing abnormalities in sporadic Alzheimer’s disease (AD). However little is known about snRNP biology in early onset AD due to autosomal dominant genetic mutations or trisomy 21 in Down syndrome. Therefore we investigated snRNP biochemical and pathologic features in these disorders. Findings We performed quantitative proteomics and immunohistochemistry in postmortem brain from genetic AD cases. Electron microscopy was used to characterize ultrastructural features of pathologic aggregates. U1-70k and other snRNPs were biochemically enriched in the insoluble fraction of human brain from subjects with presenilin 1 (PS1) mutations. Aggregates of U1 snRNP-immunoreactivity formed cytoplasmic tangle-like structures in cortex of AD subjects with PS1 and amyloid precursor protein (APP) mutations as well as trisomy 21. Ultrastructural analysis with electron microscopy in an APP mutation case demonstrated snRNP immunogold labeling of paired helical filaments (PHF). Conclusions These studies identify U1 snRNP pathologic changes in brain of early onset genetic forms of AD. Since dominant genetic mutations and trisomy 21 result in dysfunctional amyloid processing, the findings suggest that aberrant β-amyloid processing may influence U1 snRNP aggregate formation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - James J Lah
- Department of Neurology, Emory University School of Medicine, Atlanta 30322, Georgia.
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Hu X, Wu R, Shehadeh LA, Zhou Q, Jiang C, Huang X, Zhang L, Gao F, Liu X, Yu H, Webster KA, Wang J. Severe hypoxia exerts parallel and cell-specific regulation of gene expression and alternative splicing in human mesenchymal stem cells. BMC Genomics 2014; 15:303. [PMID: 24758227 PMCID: PMC4234502 DOI: 10.1186/1471-2164-15-303] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 04/16/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The endosteum of the bone marrow provides a specialized hypoxic niche that may serve to preserve the integrity, pluripotency, longevity and stemness of resident mesenchymal stem cells (MSCs). To explore the molecular genetic consequences of such a niche we subjected human (h) MSCs to a pO2 of 4 mmHg and analyzed global gene expression and alternative splicing (AS) by genome-exon microarray and RT-qPCR, and phenotype by western blot and immunostaining. RESULTS Out of 446 genes differentially regulated by >2.5-fold, down-regulated genes outnumbered up-regulated genes by 243:203. Exon analyses revealed 60 hypoxia-regulated AS events with splice indices (SI) >1.0 from 53 genes and a correlation between high SI and degree of transcript regulation. Parallel analyses of a publicly available AS study on human umbilical vein endothelial cells (HUVECs) showed that there was a strong cell-specific component with only 11 genes commonly regulated in hMSCs and HUVECs and 17 common differentially spliced genes. Only 3 genes were differentially responsive to hypoxia at the gene (>2.0) and AS levels in both cell types. Functional assignments revealed unique profiles of gene expression with complex regulation of differentiation, extracellular matrix, intermediate filament and metabolic marker genes. Antioxidant genes, striated muscle genes and insulin/IGF-1 signaling intermediates were down-regulated. There was a coordinate induction of 9 out of 12 acidic keratins that along with other epithelial and cell adhesion markers implies a partial mesenchymal to epithelial transition. CONCLUSIONS We conclude that severe hypoxia confers a quiescent phenotype in hMSCs that is reflected by both the transcriptome profile and gene-specific changes of splicosome actions. The results reveal that severe hypoxia imposes markedly different patterns of gene regulation of MSCs compared with more moderate hypoxia. This is the first study to report hypoxia-regulation of AS in stem/progenitor cells and the first molecular genetic characterization of MSC in a hypoxia-induced quiescent immobile state.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Keith A Webster
- Cardiovascular Key Lab of Zhejiang Province, Department of Cardiology, The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, P,R, China.
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Hales CM, Dammer EB, Diner I, Yi H, Seyfried NT, Gearing M, Glass JD, Montine TJ, Levey AI, Lah JJ. Aggregates of small nuclear ribonucleic acids (snRNAs) in Alzheimer's disease. Brain Pathol 2014; 24:344-51. [PMID: 24571648 DOI: 10.1111/bpa.12133] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/13/2014] [Indexed: 01/04/2023] Open
Abstract
We recently discovered that protein components of the ribonucleic acid (RNA) spliceosome form cytoplasmic aggregates in Alzheimer's disease (AD) brain, resulting in widespread changes in RNA splicing. However, the involvement of small nuclear RNAs (snRNAs), also key components of the spliceosome complex, in the pathology of AD remains unknown. Using immunohistochemical staining of post-mortem human brain and spinal cord, we identified cytoplasmic tangle-shaped aggregates of snRNA in both sporadic and familial AD cases but not in aged controls or other neurodegenerative disorders. Immunofluorescence using antibodies reactive with the 2,2,7-trimethylguanosine cap of snRNAs and transmission electron microscopy demonstrated snRNA localization with tau and paired helical filaments, the main component of neurofibrillary tangles. Quantitative real-time polymerase chain reaction (PCR) showed U1 snRNA accumulation in the insoluble fraction of AD brains whereas other U snRNAs were not enriched. In combination with our previous results, these findings demonstrate that aggregates of U1 snRNA and U1 small nuclear ribonucleoproteins represent a new pathological hallmark of AD.
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Affiliation(s)
- Chadwick M Hales
- Center for Neurodegenerative Disease, Emory University, Atlanta, GA; Department of Neurology, Emory University School of Medicine, Atlanta, GA
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Fant X, Durieu E, Chicanne G, Payrastre B, Sbrissa D, Shisheva A, Limanton E, Carreaux F, Bazureau JP, Meijer L. cdc-like/dual-specificity tyrosine phosphorylation-regulated kinases inhibitor leucettine L41 induces mTOR-dependent autophagy: implication for Alzheimer's disease. Mol Pharmacol 2014; 85:441-50. [PMID: 24366666 PMCID: PMC6067634 DOI: 10.1124/mol.113.090837] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/23/2013] [Indexed: 12/26/2022] Open
Abstract
Leucettines, a family of pharmacological inhibitors of dual-specificity tyrosine phosphorylation regulated kinases and cdc-like kinases (CLKs), are currently under investigation for their potential therapeutic application to Down syndrome and Alzheimer's disease. We here report that leucettine L41 triggers bona fide autophagy in osteosarcoma U-2 OS cells and immortalized mouse hippocampal HT22 cells, characterized by microtubule-associated protein light chain 3 membrane translocation and foci formation. Leucettine L41-triggered autophagy requires the Unc-51-like kinase and is sensitive to the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and 3-methyladenine, suggesting that it acts through the mammalian target of rapamycin (mTOR)/PI3K-dependent pathway. Leucettine L41 does not act by modifying the autophagic flux of vesicles. Leucettine L41-induced autophagy correlates best with inhibition of CLKs. Leucettine L41 modestly inhibited phosphatidylinositol-3-phosphate 5-kinase, FYVE domain-containing activity as tested both in vitro and in vivo, which may also contribute to autophagy induction. Altogether these results demonstrate that leucettines can activate the autophagic mTOR/PI3K pathway, a characteristic that may turn advantageous in the context of Alzheimer's disease treatment.
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Affiliation(s)
- Xavier Fant
- Centre National de la Recherche Scientifique (CNRS), USR3151, "Protein Phosphorylation and Human Disease," Station Biologique, Roscoff cedex, France (X.F., E.D.); Institut National de la Santé et de la Recherche Médicale/Université Paul Sabatier Unité Mixte de Recherche (UMR) 1048, "Production et fonctions plaquettaires: signalisation et phosphoinositides" group, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), Toulouse cedex, France (G.C., B.P.); Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan (D.S., A.S.); Laboratoire Sciences Chimiques de Rennes, UMR CNRS 6226, Groupe Ingénierie Chimique et Molécules pour le Vivant (ICMV), Université de Rennes, Campus de Beaulieu, Rennes cedex, France (E.L., F.C., J.-P.B.); and ManRos Therapeutics, Perharidy Research Center, Roscoff, Bretagne, France (L.M.)
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59
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Caillet-Boudin ML, Fernandez-Gomez FJ, Tran H, Dhaenens CM, Buee L, Sergeant N. Brain pathology in myotonic dystrophy: when tauopathy meets spliceopathy and RNAopathy. Front Mol Neurosci 2014; 6:57. [PMID: 24409116 PMCID: PMC3885824 DOI: 10.3389/fnmol.2013.00057] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/20/2013] [Indexed: 01/18/2023] Open
Abstract
Myotonic dystrophy (DM) of type 1 and 2 (DM1 and DM2) are inherited autosomal dominant diseases caused by dynamic and unstable expanded microsatellite sequences (CTG and CCTG, respectively) in the non-coding regions of the genes DMPK and ZNF9, respectively. These mutations result in the intranuclear accumulation of mutated transcripts and the mis-splicing of numerous transcripts. This so-called RNA gain of toxic function is the main feature of an emerging group of pathologies known as RNAopathies. Interestingly, in addition to these RNA inclusions, called foci, the presence of neurofibrillary tangles (NFT) in patient brains also distinguishes DM as a tauopathy. Tauopathies are a group of nearly 30 neurodegenerative diseases that are characterized by intraneuronal protein aggregates of the microtubule-associated protein Tau (MAPT) in patient brains. Furthermore, a number of neurodegenerative diseases involve the dysregulation of splicing regulating factors and have been characterized as spliceopathies. Thus, myotonic dystrophies are pathologies resulting from the interplay among RNAopathy, spliceopathy, and tauopathy. This review will describe how these processes contribute to neurodegeneration. We will first focus on the tauopathy associated with DM1, including clinical symptoms, brain histology, and molecular mechanisms. We will also discuss the features of DM1 that are shared by other tauopathies and, consequently, might participate in the development of a tauopathy. Moreover, we will discuss the determinants common to both RNAopathies and spliceopathies that could interfere with tau-related neurodegeneration.
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Affiliation(s)
- Marie-Laure Caillet-Boudin
- Alzheimer and Tauopathies, Faculty of Medicine, Jean-Pierre Aubert Research Centre, Institute of Predictive Medicine and Therapeutic Research, Inserm, UMR 837 Lille, France ; University of Lille Nord de France, UDSL Lille, France
| | - Francisco-Jose Fernandez-Gomez
- Alzheimer and Tauopathies, Faculty of Medicine, Jean-Pierre Aubert Research Centre, Institute of Predictive Medicine and Therapeutic Research, Inserm, UMR 837 Lille, France ; University of Lille Nord de France, UDSL Lille, France
| | - Hélène Tran
- Alzheimer and Tauopathies, Faculty of Medicine, Jean-Pierre Aubert Research Centre, Institute of Predictive Medicine and Therapeutic Research, Inserm, UMR 837 Lille, France ; University of Lille Nord de France, UDSL Lille, France
| | - Claire-Marie Dhaenens
- Alzheimer and Tauopathies, Faculty of Medicine, Jean-Pierre Aubert Research Centre, Institute of Predictive Medicine and Therapeutic Research, Inserm, UMR 837 Lille, France ; University of Lille Nord de France, UDSL Lille, France
| | - Luc Buee
- Alzheimer and Tauopathies, Faculty of Medicine, Jean-Pierre Aubert Research Centre, Institute of Predictive Medicine and Therapeutic Research, Inserm, UMR 837 Lille, France ; University of Lille Nord de France, UDSL Lille, France
| | - Nicolas Sergeant
- Alzheimer and Tauopathies, Faculty of Medicine, Jean-Pierre Aubert Research Centre, Institute of Predictive Medicine and Therapeutic Research, Inserm, UMR 837 Lille, France ; University of Lille Nord de France, UDSL Lille, France
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Guennewig B, Cooper AA. The Central Role of Noncoding RNA in the Brain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 116:153-94. [DOI: 10.1016/b978-0-12-801105-8.00007-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Abstract
Alternative pre-mRNA splicing is an integral part of gene regulation in eukaryotes. Here we provide a basic overview of the various types of alternative splicing, as well as the functional role, highlighting how alternative splicing varies across phylogeny. Regulated alternative splicing can affect protein function and ultimately impact biological outcomes. We examine the possibility that portions of alternatively spliced transcripts are the result of stochastic processes rather than regulated. We discuss the implications of misregulated alternative splicing and explore of the role of alternative splicing in human disease.
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Affiliation(s)
- Stacey D Wagner
- Department of Chemistry and Institute of Molecular Biology, University of Oregon, Eugene, OR, USA
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Mills JD, Kawahara Y, Janitz M. Strand-Specific RNA-Seq Provides Greater Resolution of Transcriptome Profiling. Curr Genomics 2013; 14:173-81. [PMID: 24179440 PMCID: PMC3664467 DOI: 10.2174/1389202911314030003] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/31/2013] [Accepted: 02/25/2013] [Indexed: 01/11/2023] Open
Abstract
RNA-Seq is a recently developed sequencing technology, that through the analysis of cDNA allows for unique insights into the transcriptome of a cell. The data generated by RNA-Seq provides information on gene expression, alternative splicing events and the presence of non-coding RNAs. It has been realised non-coding RNAs are more then just artefacts of erroneous transcription and play vital regulatory roles at the genomic, transcriptional and translational level. Transcription of the DNA sense strand produces antisense transcripts. This is known as antisense transcription and often results in the production of non-coding RNAs that are complementary to their associated sense transcripts. Antisense tran-scription has been identified in bacteria, fungi, protozoa, plants, invertebrates and mammals. It seems that antisense tran-scriptional ‘hot spots’ are located around nucleosome-free regions such as those associated with promoters, indicating that it is likely that antisense transcripts carry out important regulatory functions. This underlines the importance of identifying the presence and understanding the function of these antisense non-coding RNAs. The information concerning strand ori-gin is often lost during conventional RNA-Seq; capturing this information would substantially increase the worth of any RNA-Seq experiment. By manipulating the input cDNA during the template preparation stage it is possible to retain this vital information. This forms the basis of strand-specific RNA-Seq. With an ability to unlock immense portions of new in-formation surrounding the transcriptome, this cutting edge technology may hold the key to developing a greater under-standing of the transcriptome.
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Affiliation(s)
- James Dominic Mills
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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63
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U1 small nuclear ribonucleoprotein complex and RNA splicing alterations in Alzheimer's disease. Proc Natl Acad Sci U S A 2013; 110:16562-7. [PMID: 24023061 PMCID: PMC3799305 DOI: 10.1073/pnas.1310249110] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Deposition of insoluble protein aggregates is a hallmark of neurodegenerative diseases. The universal presence of β-amyloid and tau in Alzheimer's disease (AD) has facilitated advancement of the amyloid cascade and tau hypotheses that have dominated AD pathogenesis research and therapeutic development. However, the underlying etiology of the disease remains to be fully elucidated. Here we report a comprehensive study of the human brain-insoluble proteome in AD by mass spectrometry. We identify 4,216 proteins, among which 36 proteins accumulate in the disease, including U1-70K and other U1 small nuclear ribonucleoprotein (U1 snRNP) spliceosome components. Similar accumulations in mild cognitive impairment cases indicate that spliceosome changes occur in early stages of AD. Multiple U1 snRNP subunits form cytoplasmic tangle-like structures in AD but not in other examined neurodegenerative disorders, including Parkinson disease and frontotemporal lobar degeneration. Comparison of RNA from AD and control brains reveals dysregulated RNA processing with accumulation of unspliced RNA species in AD, including myc box-dependent-interacting protein 1, clusterin, and presenilin-1. U1-70K knockdown or antisense oligonucleotide inhibition of U1 snRNP increases the protein level of amyloid precursor protein. Thus, our results demonstrate unique U1 snRNP pathology and implicate abnormal RNA splicing in AD pathogenesis.
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Singh NN, Lawler MN, Ottesen EW, Upreti D, Kaczynski JR, Singh RN. An intronic structure enabled by a long-distance interaction serves as a novel target for splicing correction in spinal muscular atrophy. Nucleic Acids Res 2013; 41:8144-65. [PMID: 23861442 PMCID: PMC3783185 DOI: 10.1093/nar/gkt609] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/18/2013] [Accepted: 06/19/2013] [Indexed: 01/16/2023] Open
Abstract
Here, we report a long-distance interaction (LDI) as a critical regulator of alternative splicing of Survival Motor Neuron 2 (SMN2) exon 7, skipping of which is linked to spinal muscular atrophy (SMA), a leading genetic disease of children and infants. We show that this LDI is linked to a unique intra-intronic structure that we term internal stem through LDI-1 (ISTL1). We used site-specific mutations and Selective 2'-Hydroxyl Acylation analyzed by Primer Extension to confirm the formation and functional significance of ISTL1. We demonstrate that the inhibitory effect of ISTL1 is independent of hnRNP A1/A2B1 and PTB1 previously implicated in SMN2 exon 7 splicing. We show that an antisense oligonucleotide-mediated sequestration of the 3' strand of ISTL1 fully corrects SMN2 exon 7 splicing and restores high levels of SMN and Gemin2, a SMN-interacting protein, in SMA patient cells. Our results also reveal that the 3' strand of ISTL1 and upstream sequences constitute an inhibitory region that we term intronic splicing silencer N2 (ISS-N2). This is the first report to demonstrate a critical role of a structure-associated LDI in splicing regulation of an essential gene linked to a genetic disease. Our findings expand the repertoire of potential targets for an antisense oligonucleotide-mediated therapy of SMA.
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Affiliation(s)
- Natalia N. Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA, Department of Biochemistry, Iowa State University, Ames, IA 50011, USA, Molecular Cellular and Developmental Biology Program, Iowa State University, Ames, IA 50011, USA and Biology Program, Iowa State University, Ames, IA 50011, USA
| | - Mariah N. Lawler
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA, Department of Biochemistry, Iowa State University, Ames, IA 50011, USA, Molecular Cellular and Developmental Biology Program, Iowa State University, Ames, IA 50011, USA and Biology Program, Iowa State University, Ames, IA 50011, USA
| | - Eric W. Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA, Department of Biochemistry, Iowa State University, Ames, IA 50011, USA, Molecular Cellular and Developmental Biology Program, Iowa State University, Ames, IA 50011, USA and Biology Program, Iowa State University, Ames, IA 50011, USA
| | - Daya Upreti
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA, Department of Biochemistry, Iowa State University, Ames, IA 50011, USA, Molecular Cellular and Developmental Biology Program, Iowa State University, Ames, IA 50011, USA and Biology Program, Iowa State University, Ames, IA 50011, USA
| | - Jennifer R. Kaczynski
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA, Department of Biochemistry, Iowa State University, Ames, IA 50011, USA, Molecular Cellular and Developmental Biology Program, Iowa State University, Ames, IA 50011, USA and Biology Program, Iowa State University, Ames, IA 50011, USA
| | - Ravindra N. Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA, Department of Biochemistry, Iowa State University, Ames, IA 50011, USA, Molecular Cellular and Developmental Biology Program, Iowa State University, Ames, IA 50011, USA and Biology Program, Iowa State University, Ames, IA 50011, USA
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Abstract
Dysfunctions at the level of RNA processing have recently been shown to play a fundamental role in the pathogenesis of many neurodegenerative diseases. Several proteins responsible for these dysfunctions (TDP-43, FUS/TLS, and hnRNP A/Bs) belong to the nuclear class of heterogeneous ribonucleoproteins (hnRNPs) that predominantly function as general regulators of both coding and noncoding RNA metabolism. The discovery of the importance of these factors in mediating neuronal death has represented a major paradigmatic shift in our understanding of neurodegenerative processes. As a result, these discoveries have also opened the way toward novel biomolecular screening approaches in our search for therapeutic options. One of the major hurdles in this search is represented by the correct identification of the most promising targets to be prioritized. These may include aberrant aggregation processes, protein-protein interactions, RNA-protein interactions, or specific cellular pathways altered by disease. In this review, we discuss these four major options together with their various advantages and drawbacks.
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Affiliation(s)
- Maurizio Romano
- 1Department of Life Sciences, University of Trieste, Trieste, Italy
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Tang JY, Lee JC, Hou MF, Wang CL, Chen CC, Huang HW, Chang HW. Alternative splicing for diseases, cancers, drugs, and databases. ScientificWorldJournal 2013; 2013:703568. [PMID: 23766705 PMCID: PMC3674688 DOI: 10.1155/2013/703568] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 04/30/2013] [Indexed: 01/05/2023] Open
Abstract
Alternative splicing is a major diversification mechanism in the human transcriptome and proteome. Several diseases, including cancers, have been associated with dysregulation of alternative splicing. Thus, correcting alternative splicing may restore normal cell physiology in patients with these diseases. This paper summarizes several alternative splicing-related diseases, including cancers and their target genes. Since new cancer drugs often target spliceosomes, several clinical drugs and natural products or their synthesized derivatives were analyzed to determine their effects on alternative splicing. Other agents known to have modulating effects on alternative splicing during therapeutic treatment of cancer are also discussed. Several commonly used bioinformatics resources are also summarized.
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Affiliation(s)
- Jen-Yang Tang
- Department of Radiation Oncology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Radiation Oncology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Jin-Ching Lee
- Department of Biotechnology, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Ming-Feng Hou
- Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung 807, Taiwan
| | - Chun-Lin Wang
- Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu 300, Taiwan
| | - Chien-Chi Chen
- Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu 300, Taiwan
| | - Hurng-Wern Huang
- Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung 807, Taiwan
| | - Hsueh-Wei Chang
- Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 807, Taiwan
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67
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Wong J. Altered expression of RNA splicing proteins in Alzheimer's disease patients: evidence from two microarray studies. Dement Geriatr Cogn Dis Extra 2013; 3:74-85. [PMID: 23637700 PMCID: PMC3617979 DOI: 10.1159/000348406] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND/AIMS Dysregulation of pre-mRNA splicing from an altered expression of RNA splice-regulatory proteins may act as the convergence point underlying aberrant gene expression changes in Alzheimer's disease (AD). METHODS Two microarray datasets from a control/AD postmortem brain cohort of 31 subjects - 9 controls and 22 AD subjects (National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database) - were used. RESULTS Between the two microarray studies, the expression of six splice-regulatory protein genes showed concordant changes in AD. These genes were then correlated with gene expression changes of transcripts reported to be altered in AD. Amyloid beta (A4) precursor protein and tropomyosin receptor kinase B transcripts were found to correlate significantly with the same splice-regulatory proteins in the two studies. CONCLUSION This study highlights a susceptibility network that can potentially link a number of susceptibility genes.
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Affiliation(s)
- Jenny Wong
- Illawarra Health and Medical Research Institute, and School of Biological Sciences, University of Wollongong, Wollongong, N.S.W., Australia
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68
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Mills JD, Nalpathamkalam T, Jacobs HI, Janitz C, Merico D, Hu P, Janitz M. RNA-Seq analysis of the parietal cortex in Alzheimer's disease reveals alternatively spliced isoforms related to lipid metabolism. Neurosci Lett 2013; 536:90-5. [DOI: 10.1016/j.neulet.2012.12.042] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 12/25/2012] [Indexed: 11/26/2022]
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69
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Hitzemann R, Bottomly D, Darakjian P, Walter N, Iancu O, Searles R, Wilmot B, McWeeney S. Genes, behavior and next-generation RNA sequencing. GENES, BRAIN, AND BEHAVIOR 2013; 12:1-12. [PMID: 23194347 PMCID: PMC6050050 DOI: 10.1111/gbb.12007] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 10/31/2012] [Accepted: 11/21/2012] [Indexed: 12/30/2022]
Abstract
Advances in next-generation sequencing suggest that RNA-Seq is poised to supplant microarray-based approaches for transcriptome analysis. This article briefly reviews the use of microarrays in the brain-behavior context and then illustrates why RNA-Seq is a superior strategy. Compared with microarrays, RNA-Seq has a greater dynamic range, detects both coding and noncoding RNAs, is superior for gene network construction, detects alternative spliced transcripts, detects allele specific expression and can be used to extract genotype information, e.g. nonsynonymous coding single nucleotide polymorphisms. Examples of where RNA-Seq has been used to assess brain gene expression are provided. Despite the advantages of RNA-Seq, some disadvantages remain. These include the high cost of RNA-Seq and the computational complexities associated with data analysis. RNA-Seq embraces the complexity of the transcriptome and provides a mechanism to understand the underlying regulatory code; the potential to inform the brain-behavior relationship is substantial.
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Affiliation(s)
- R Hitzemann
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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70
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Kavanagh T, Mills JD, Kim WS, Halliday GM, Janitz M. Pathway analysis of the human brain transcriptome in disease. J Mol Neurosci 2012; 51:28-36. [PMID: 23263795 DOI: 10.1007/s12031-012-9940-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 12/10/2012] [Indexed: 01/10/2023]
Abstract
Pathway analysis is a powerful method for discerning differentially regulated genes and elucidating their biological importance. It allows for the identification of perturbed or aberrantly expressed genes within a biological context from extensive data sets and offers a simplistic approach for interrogating such data sets. With the growing use of microarrays and RNA-Seq, data for genome-wide studies are growing at an alarming rate, and the use of deep sequencing is revealing elements of the genome previously uncharacterised. Through the employment of pathway analysis, mechanisms in complex diseases may be explored and novel causatives found primarily through differentially regulated genes. Further, with the implementation of next generation sequencing, a deeper resolution may be attained, particularly in identification of isoform diversity and SNPs. Here, we look at a broad overview of pathway analysis in the human brain transcriptome and its relevance in teasing out underlying causes of complex diseases. We will outline processes in data gathering and analysis of particular diseases in which these approaches have been successful.
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Affiliation(s)
- Tomas Kavanagh
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
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71
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The Murine PSE/TATA-dependent transcriptome: evidence of functional homologies with its human counterpart. Int J Mol Sci 2012. [PMID: 23203095 PMCID: PMC3509611 DOI: 10.3390/ijms131114813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A series of recent studies demonstrated an unexpectedly high frequency of intronic RNA polymerase (pol) III transcription units spread throughout the human genome. The investigation of a subset of these transcripts revealed their tissue/cell-specific transcription together with the involvement in relevant physiopathological pathways. Despite this evidence, these transcripts did not seem to have murine orthologs, based on their nucleotide sequence, resulting in a limitation of the experimental approaches aimed to study their function. In this work, we have extended our investigation to the murine genome identifying 121 pairs of mouse/human transcripts displaying syntenic subchromosomal localization. The analysis in silico of this set of putative noncoding (nc)RNAs suggest their association with alternative splicing as suggested by recent experimental evidence. The investigation of one of these pairs taken as experimental model in mouse hippocampal neurons provided evidence of a human/mouse functional homology that does not depend on underlying sequence conservation. In this light, the collection of transcriptional units here reported can be considered as a novel source for the identification and the study of novel regulatory elements involved in relevant biological processes.
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72
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Southwell AL, Skotte NH, Bennett CF, Hayden MR. Antisense oligonucleotide therapeutics for inherited neurodegenerative diseases. Trends Mol Med 2012; 18:634-43. [PMID: 23026741 DOI: 10.1016/j.molmed.2012.09.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/25/2012] [Accepted: 09/07/2012] [Indexed: 12/12/2022]
Abstract
The rising median age of our population and the age-dependent risk of neurodegeneration translate to exponentially increasing numbers of afflicted individuals in the coming years. Although symptomatic treatments are available for some neurodegenerative diseases, most are only moderately efficacious and are often associated with significant side effects. The development of small molecule, disease-modifying drugs has been hindered by complex pathogenesis and a failure to clearly define the rate-limiting steps in disease progression. An alternative approach is to directly target the mutant gene product or a defined causative protein. Antisense oligonucleotides (ASOs) - with their diverse functionality, high target specificity, and relative ease of central nervous system (CNS) delivery - are uniquely positioned as potential therapies for neurological diseases. Here we review the development of ASOs for the treatment of inherited neurodegenerative diseases.
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Affiliation(s)
- Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, V5Z 4H4, Canada.
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73
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Dembowski JA, An P, Scoulos-Hanson M, Yeo G, Han J, Fu XD, Grabowski PJ. Alternative Splicing of a Novel Inducible Exon Diversifies the CASK Guanylate Kinase Domain. J Nucleic Acids 2012; 2012:816237. [PMID: 23008758 PMCID: PMC3447378 DOI: 10.1155/2012/816237] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/10/2012] [Indexed: 12/29/2022] Open
Abstract
Alternative pre-mRNA splicing has a major impact on cellular functions and development with the potential to fine-tune cellular localization, posttranslational modification, interaction properties, and expression levels of cognate proteins. The plasticity of regulation sets the stage for cells to adjust the relative levels of spliced mRNA isoforms in response to stress or stimulation. As part of an exon profiling analysis of mouse cortical neurons stimulated with high KCl to induce membrane depolarization, we detected a previously unrecognized exon (E24a) of the CASK gene, which encodes for a conserved peptide insertion in the guanylate kinase interaction domain. Comparative sequence analysis shows that E24a appeared selectively in mammalian CASK genes as part of a >3,000 base pair intron insertion. We demonstrate that a combination of a naturally defective 5' splice site and negative regulation by several splicing factors, including SC35 (SRSF2) and ASF/SF2 (SRSF1), drives E24a skipping in most cell types. However, this negative regulation is countered with an observed increase in E24a inclusion after neuronal stimulation and NMDA receptor signaling. Taken together, E24a is typically a skipped exon, which awakens during neuronal stimulation with the potential to diversify the protein interaction properties of the CASK polypeptide.
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Affiliation(s)
- Jill A. Dembowski
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Ping An
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | - Gene Yeo
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Stem Cell Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joonhee Han
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paula J. Grabowski
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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Weigand JE, Boeckel JN, Gellert P, Dimmeler S. Hypoxia-induced alternative splicing in endothelial cells. PLoS One 2012; 7:e42697. [PMID: 22876330 PMCID: PMC3411717 DOI: 10.1371/journal.pone.0042697] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 07/11/2012] [Indexed: 01/12/2023] Open
Abstract
Background Adaptation to low oxygen by changing gene expression is vitally important for cell survival and tissue development. The sprouting of new blood vessels, initiated from endothelial cells, restores the oxygen supply of ischemic tissues. In contrast to the transcriptional response induced by hypoxia, which is mainly mediated by members of the HIF family, there are only few studies investigating alternative splicing events. Therefore, we performed an exon array for the genome-wide analysis of hypoxia-related changes of alternative splicing in endothelial cells. Methodology/Principal findings Human umbilical vein endothelial cells (HUVECs) were incubated under hypoxic conditions (1% O2) for 48 h. Genome-wide transcript and exon expression levels were assessed using the Affymetrix GeneChip Human Exon 1.0 ST Array. We found altered expression of 294 genes after hypoxia treatment. Upregulated genes are highly enriched in glucose metabolism and angiogenesis related processes, whereas downregulated genes are mainly connected to cell cycle and DNA repair. Thus, gene expression patterns recapitulate known adaptations to low oxygen supply. Alternative splicing events, until now not related to hypoxia, are shown for nine genes: six which are implicated in angiogenesis-mediated cytoskeleton remodeling (cask, itsn1, larp6, sptan1, tpm1 and robo1); one, which is involved in the synthesis of membrane-anchors (pign) and two universal regulators of gene expression (cugbp1 and max). Conclusions/Significance For the first time, this study investigates changes in splicing in the physiological response to hypoxia on a genome-wide scale. Nine alternative splicing events, until now not related to hypoxia, are reported, considerably expanding the information on splicing changes due to low oxygen supply. Therefore, this study provides further knowledge on hypoxia induced gene expression changes and presents new starting points to study the hypoxia adaptation of endothelial cells.
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Affiliation(s)
- Julia E Weigand
- Institute for Cardiovascular Regeneration, Center of Molecular Medicine, Johann Wolfgang Goethe University Frankfurt, Frankfurt am Main, Germany.
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