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Nikom D, Zheng S. Alternative splicing in neurodegenerative disease and the promise of RNA therapies. Nat Rev Neurosci 2023; 24:457-473. [PMID: 37336982 DOI: 10.1038/s41583-023-00717-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2023] [Indexed: 06/21/2023]
Abstract
Alternative splicing generates a myriad of RNA products and protein isoforms of different functions from a single gene. Dysregulated alternative splicing has emerged as a new mechanism broadly implicated in the pathogenesis of neurodegenerative diseases such as Alzheimer disease, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson disease and repeat expansion diseases. Understanding the mechanisms and functional outcomes of abnormal splicing in neurological disorders is vital in developing effective therapies to treat mis-splicing pathology. In this Review, we discuss emerging research and evidence of the roles of alternative splicing defects in major neurodegenerative diseases and summarize the latest advances in RNA-based therapeutic strategies to target these disorders.
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Affiliation(s)
- David Nikom
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, USA
- Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA, USA
| | - Sika Zheng
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, USA.
- Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA, USA.
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA, USA.
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2
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Cheng D, Su L, Wang X, Li X, Li L, Hu M, Lu Y. Extract of Cynomorium songaricum ameliorates mitochondrial ultrastructure impairments and dysfunction in two different in vitro models of Alzheimer's disease. BMC Complement Med Ther 2021; 21:206. [PMID: 34372842 PMCID: PMC8351341 DOI: 10.1186/s12906-021-03375-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 07/06/2021] [Indexed: 12/23/2022] Open
Abstract
Background Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders, but there is still no effective way to stop or slow its progression. Our previous studies demonstrated that extract of Cynomorium songaricum (ECS), a Chinese herbal medicine, had neuroprotective effects in AD models in vivo. However, the pharmacological mechanism of ECS in AD is still unclear. Methods To study the mechanisms of action of the effects of ECS on AD, we used Aβ25–35- and H2O2-exposed HT22 cells to mimic specific stages of AD in vitro. The mitochondrial membrane potential (MMP), intracellular ATP, intracellular reactive oxygen species (ROS), and expression levels of mitochondrial dynamics-related proteins in each group were examined. Furthermore, we explored the mechanisms by which ECS reduces the phosphorylation of Drp1 at Ser637 and the changes in the concentrations of intracellular calcium ions in the two models after FK506 intervention. Results The results showed that ECS significantly enhanced the MMP (P < 0.05), increased intracellular ATP levels (P < 0.05) and decreased intracellular ROS levels in the Aβ- and H2O2-induced cell models (P < 0.05). Additionally, ECS regulated the expression levels of mitochondrial dynamics-related proteins by reducing the phosphorylation of Drp1 at Ser637 (P < 0.05) and decreasing the expression of Fis1 in the H2O2-induced models (P < 0.05). Further study indicated that ECS reduced the overload of intracellular calcium (P < 0.05). Conclusion Our study results suggest that ECS protects the mitochondrial ultrastructure, ameliorates mitochondrial dysfunction, and maintains mitochondrial dynamics in AD models. Supplementary Information The online version contains supplementary material available at 10.1186/s12906-021-03375-2.
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Affiliation(s)
- Dan Cheng
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.,School of Chinese Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Lei Su
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Xu Wang
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Xinjie Li
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Lingling Li
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Mengyuan Hu
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Yi Lu
- School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.
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Adlimoghaddam A, Odero GG, Glazner G, Turner RS, Albensi BC. Nilotinib Improves Bioenergetic Profiling in Brain Astroglia in the 3xTg Mouse Model of Alzheimer's Disease. Aging Dis 2021; 12:441-465. [PMID: 33815876 PMCID: PMC7990369 DOI: 10.14336/ad.2020.0910] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/10/2020] [Indexed: 12/27/2022] Open
Abstract
Current treatments targeting amyloid beta in Alzheimer's disease (AD) have minimal efficacy, which results in a huge unmet medical need worldwide. Accumulating data suggest that brain mitochondrial dysfunction play a critical role in AD pathogenesis. Targeting cellular mechanisms associated with mitochondrial dysfunction in AD create a novel approach for drug development. This study investigated the effects of nilotinib, as a selective tyrosine kinase inhibitor, in astroglia derived from 3xTg-AD mice versus their C57BL/6-controls. Parameters included oxygen consumption rates (OCR), ATP, cytochrome c oxidase (COX), citrate synthase (CS) activity, alterations in oxidative phosphorylation (OXPHOS), nuclear factor kappa B (NF-κB), key regulators of mitochondrial dynamics (mitofusin (Mfn1), dynamin-related protein 1 (Drp1)), and mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator1-alpha (PGC-1α), calcium/calmodulin-dependent protein kinase II (CaMKII), and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)). Nilotinib increased OCR, ATP, COX, Mfn1, and OXPHOS levels in 3xTg astroglia. No significant differences were detected in levels of Drp1 protein and CS activity. Nilotinib enhanced mitochondrial numbers, potentially through a CaMKII-PGC1α-Nrf2 pathway in 3xTg astroglia. Additionally, nilotinib-induced OCR increases were reduced in the presence of the NF-κB inhibitor, Bay11-7082. The data suggest that NF-κB signaling is intimately involved in nilotinib-induced changes in bioenergetics in 3xTg brain astroglia. Nilotinib increased translocation of the NF-κB p50 subunit into the nucleus of 3xTg astroglia that correlates with an increased expression and activation of NF-κB. The current findings support a role for nilotinib in improving mitochondrial function and suggest that astroglia may be a key therapeutic target in treating AD.
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Affiliation(s)
- Aida Adlimoghaddam
- 1Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, MB, Canada
| | - Gary G Odero
- 1Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, MB, Canada
| | - Gordon Glazner
- 1Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, MB, Canada.,2Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - R Scott Turner
- 3Department of Neurology, Georgetown University, Washington, DC, USA
| | - Benedict C Albensi
- 1Division of Neurodegenerative Disorders, St. Boniface Hospital Research, Winnipeg, MB, Canada.,2Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
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Visioli F, Rodríguez-Pérez M, Gómez-Torres Ó, Pintado-Losa C, Burgos-Ramos E. Hydroxytyrosol improves mitochondrial energetics of a cellular model of Alzheimer's disease. Nutr Neurosci 2020; 25:990-1000. [PMID: 33023416 DOI: 10.1080/1028415x.2020.1829344] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondrial energetic deficit is one of the hallmarks of neurodegenerative disorders, e.g. Alzheimer´s disease (AD). Adherence to a Mediterranean diet is associated with lower incidence of cognitive decline and AD and extra virgin olive oil's (poly)phenols such as oleuropein and hydroxytyrosol (HT) are being actively studied in this respect. In this study, we assessed the effects of HT on mitochondrial energetic dysfunction in the 7PA2 cells cellular model, i.e. one of the best cellular models of Aβ toxicity with a well-characterized mitochondrial dysfunction typically observed in AD. We report an increase of new mitochondria at 8 h post HT-treatment, which was followed by higher mitochondrial fusion. Further, ATP concentrations were significantly increased after 24 h of treatment with HT as compared with controls. Our data suggest that HT may revert the energetic deficit of a cellular model of AD by potentiating mitochondrial activity. Because HT is being proposed as dietary supplement or component of functional foods, future studies in appropriate animal models and - eventually - humans are warranted to further investigate its potential neuroprotective actions in AD.
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Affiliation(s)
- Francesco Visioli
- Department of Molecular Medicine, University of Padova, Padua, Italy.,IMDEA-Food, CEI UAM+CSIC, Madrid, Spain
| | - María Rodríguez-Pérez
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Óscar Gómez-Torres
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Cristina Pintado-Losa
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Emma Burgos-Ramos
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
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Emmerzaal TL, Rodenburg RJ, Tanila H, Verweij V, Kiliaan AJ, Kozicz T. Age-Dependent Decrease of Mitochondrial Complex II Activity in a Familial Mouse Model for Alzheimer's Disease. J Alzheimers Dis 2019; 66:75-82. [PMID: 30248054 DOI: 10.3233/jad-180337] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative disorder for which the exact etiology is largely unknown. An increasingly recognized and investigated notion is the pathogenic role of mitochondrial dysfunction in AD. We assessed mitochondrial oxidative-phosphorylation (OXPHOS) enzyme activities in the APPswe/PS1ΔE9 mouse model from 4.5 to 14 months of age. We show an age-dependent decrease in mitochondrial complex-II activity starting at 9 months in APP/PS1 mice. Other enzymes of the OXPHOS do not show any alterations. Since amyloid-β (Aβ) plaques are already present from 4 months of age, mitochondrial dysfunction likely occurs downstream of Aβ pathology in this mouse model.
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Affiliation(s)
- Tim L Emmerzaal
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Richard J Rodenburg
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Vivienne Verweij
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Amanda J Kiliaan
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Tamas Kozicz
- Department of Anatomy, Radboud University Medical Center, Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
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Andrew RJ, Fisher K, Heesom KJ, Kellett KAB, Hooper NM. Quantitative interaction proteomics reveals differences in the interactomes of amyloid precursor protein isoforms. J Neurochem 2019; 149:399-412. [PMID: 30664241 DOI: 10.1111/jnc.14666] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/21/2018] [Accepted: 01/16/2019] [Indexed: 02/04/2023]
Abstract
The generation of the amyloid-β (Aβ) peptides from the amyloid precursor protein (APP) through sequential proteolysis by β- and γ-secretases is a key pathological event in the initiation and propagation of Alzheimer's disease. Aβ and the transcriptionally active APP intracellular domain are generated preferentially from the APP695 isoform compared to the longer APP751 isoform. As the Aβ and amyloid precursor protein intracellular domain produced from cleavage of APP695 and APP751 are identical we hypothesised that the two isoforms have differences within their interactomes which mediate the differential processing of the two isoforms. To investigate this, we applied a proteomics-based approach to identify differences in the interactomes of the APP695 and APP751 isoforms. Using stable isotope labelling of amino acids in cell culture and quantitative proteomics, we compared the interactomes of APP695 and APP751 expressed in human SH-SY5Y cells. Through this approach, we identified enrichment of proteins involved in mitochondrial function, the nuclear pore and nuclear transport specifically in the APP695 interactome. Further interrogation of the APP interactome and subsequent experimental validation (co-immunoprecipitation and siRNA knockdown) revealed GAP43 as a specific modulator of APP751 proteolysis, altering Aβ generation. Our data indicate that interrogation of the APP interactome can be exploited to identify proteins which influence APP proteolysis and Aβ production in an isoform dependent-manner. Cover Image for this issue: doi: 10.1111/jnc.14504.
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Affiliation(s)
- Robert J Andrew
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Kate Fisher
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Kate J Heesom
- Proteomics Facility, Faculty of Medical and Veterinary Sciences, University of Bristol, Bristol, UK
| | - Katherine A B Kellett
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Nigel M Hooper
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
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Lost region in amyloid precursor protein (APP) through TALEN-mediated genome editing alters mitochondrial morphology. Sci Rep 2016; 6:22244. [PMID: 26924205 PMCID: PMC4770288 DOI: 10.1038/srep22244] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 02/10/2016] [Indexed: 12/25/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) deposition in the brain. Aβ plaques are produced through sequential β/γ cleavage of amyloid precursor protein (APP), of which there are three main APP isoforms: APP695, APP751 and APP770. KPI-APPs (APP751 and APP770) are known to be elevated in AD, but the reason remains unclear. Transcription activator-like (TAL) effector nucleases (TALENs) induce mutations with high efficiency at specific genomic loci, and it is thus possible to knock out specific regions using TALENs. In this study, we designed and expressed TALENs specific for the C-terminus of APP in HeLa cells, in which KPI-APPs are predominantly expressed. The KPI-APP mutants lack a 12-aa region that encompasses a 5-aa trans-membrane (TM) region and 7-aa juxta-membrane (JM) region. The mutated KPI-APPs exhibited decreased mitochondrial localization. In addition, mitochondrial morphology was altered, resulting in an increase in spherical mitochondria in the mutant cells through the disruption of the balance between fission and fusion. Mitochondrial dysfunction, including decreased ATP levels, disrupted mitochondrial membrane potential, increased ROS generation and impaired mitochondrial dehydrogenase activity, was also found. These results suggest that specific regions of KPI-APPs are important for mitochondrial localization and function.
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Abstract
Little is known about the molecular mechanisms whereby the human blood fluke Schistosoma japonicum is able to survive in the host venous blood system. Protease inhibitors are likely released by the parasite enabling it to avoid attack by host proteolytic enzymes and coagulation factors. Interrogation of the S. japonicum genomic sequence identified a gene, SjKI-1, homologous to that encoding a single domain Kunitz protein (Sjp_0020270) which we expressed in recombinant form in Escherichia coli and purified. SjKI-1 is highly transcribed in adult worms and eggs but its expression was very low in cercariae and schistosomula. In situ immunolocalization with anti-SjKI-1 rabbit antibodies showed the protein was present in eggs trapped in the infected mouse intestinal wall. In functional assays, SjKI-1 inhibited trypsin in the picomolar range and chymotrypsin, neutrophil elastase, FXa and plasma kallikrein in the nanomolar range. Furthermore, SjKI-1, at a concentration of 7·5 µ m, prolonged 2-fold activated partial thromboplastin time of human blood coagulation. We also demonstrate that SjKI-1 has the ability to bind Ca(++). We present, therefore, characterization of the first Kunitz protein from S. japonicum which we show has an anti-coagulant properties. In addition, its inhibition of neutrophil elastase indicates SjKI-1 have an anti-inflammatory role. Having anti-thrombotic properties, SjKI-1 may point the way towards novel treatment for hemostatic disorders.
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Salminen A, Haapasalo A, Kauppinen A, Kaarniranta K, Soininen H, Hiltunen M. Impaired mitochondrial energy metabolism in Alzheimer's disease: Impact on pathogenesis via disturbed epigenetic regulation of chromatin landscape. Prog Neurobiol 2015; 131:1-20. [PMID: 26001589 DOI: 10.1016/j.pneurobio.2015.05.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 05/05/2015] [Accepted: 05/11/2015] [Indexed: 12/14/2022]
Abstract
The amyloid cascade hypothesis for the pathogenesis of Alzheimer's disease (AD) was proposed over twenty years ago. However, the mechanisms of neurodegeneration and synaptic loss have remained elusive delaying the effective drug discovery. Recent studies have revealed that amyloid-β peptides as well as phosphorylated and fragmented tau proteins accumulate within mitochondria. This process triggers mitochondrial fission (fragmentation) and disturbs Krebs cycle function e.g. by inhibiting the activity of 2-oxoglutarate dehydrogenase. Oxidative stress, hypoxia and calcium imbalance also disrupt the function of Krebs cycle in AD brains. Recent studies on epigenetic regulation have revealed that Krebs cycle intermediates control DNA and histone methylation as well as histone acetylation and thus they have fundamental roles in gene expression. DNA demethylases (TET1-3) and histone lysine demethylases (KDM2-7) are included in the family of 2-oxoglutarate-dependent oxygenases (2-OGDO). Interestingly, 2-oxoglutarate is the obligatory substrate of 2-OGDO enzymes, whereas succinate and fumarate are the inhibitors of these enzymes. Moreover, citrate can stimulate histone acetylation via acetyl-CoA production. Epigenetic studies have revealed that AD is associated with changes in DNA methylation and histone acetylation patterns. However, the epigenetic results of different studies are inconsistent but one possibility is that they represent both coordinated adaptive responses and uncontrolled stochastic changes, which provoke pathogenesis in affected neurons. Here, we will review the changes observed in mitochondrial dynamics and Krebs cycle function associated with AD, and then clarify the mechanisms through which mitochondrial metabolites can control the epigenetic landscape of chromatin and induce pathological changes in AD.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland.
| | - Annakaisa Haapasalo
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Hilkka Soininen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Mikko Hiltunen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland
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Mitochondrial dysfunction: different routes to Alzheimer's disease therapy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:780179. [PMID: 25221640 PMCID: PMC4158152 DOI: 10.1155/2014/780179] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/29/2014] [Indexed: 01/02/2023]
Abstract
Mitochondria are dynamic ATP-generating organelle which contribute to many cellular functions including bioenergetics processes, intracellular calcium regulation, alteration of reduction-oxidation potential of cells, free radical scavenging, and activation of caspase mediated cell death. Mitochondrial functions can be negatively affected by amyloid β peptide (Aβ), an important component in Alzheimer's disease (AD) pathogenesis, and Aβ can interact with mitochondria and cause mitochondrial dysfunction. One of the most accepted hypotheses for AD onset implicates that mitochondrial dysfunction and oxidative stress are one of the primary events in the insurgence of the pathology. Here, we examine structural and functional mitochondrial changes in presence of Aβ. In particular we review data concerning Aβ import into mitochondrion and its involvement in mitochondrial oxidative stress, bioenergetics, biogenesis, trafficking, mitochondrial permeability transition pore (mPTP) formation, and mitochondrial protein interaction. Moreover, the development of AD therapy targeting mitochondria is also discussed.
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Alam S, Suzuki H, Tsukahara T. Alternative splicing regulation of APP exon 7 by RBFox proteins. Neurochem Int 2014; 78:7-17. [PMID: 25125370 DOI: 10.1016/j.neuint.2014.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 07/18/2014] [Accepted: 08/01/2014] [Indexed: 02/03/2023]
Abstract
RBFox proteins are well-known alternative splicing regulators. We have shown previously that during neuronal differentiation of P19 cells induced by all-trans retinoic acid and cell aggregation, RBFox1 shows markedly increased temporal expression. To find its key splicing regulation, we examined the effect of RBFox1 on 33 previously reported and validated neuronal splicing events of P19 cells. We observed that alternative splicing of three genes, specifically, amyloid precursor protein (APP), disks large homolog 3 (DLG3), and G protein, alpha activating activity polypeptide O (GNAO1), was altered by transient RBFox1 expression in HEK293 and HeLa cells. Moreover, an RBFox1 mutant (RBFox1FA) that was unable to bind the target RNA sequence ((U)GCAUG) did not induce these splicing events. APP generates amyloid beta peptides that are involved in the pathology of Alzheimer's disease, and therefore we examined APP alternative splicing regulation by RBFox1 and other splicing regulators. Our results indicated that RBFox proteins promote the skipping of APP exon 7, but not the inclusion of exon 8. We made APP6789 minigenes and observed that two (U)GCAUG sequences, located upstream of exon 7 and in exon 7, functioned to induce skipping of exon 7 by RBFox proteins. Overall, RBFox proteins may shift APP from exon 7 containing isoforms, APP770 and APP751, toward the exon 7 lacking isoform, APP695, which is predominant in neural tissues.
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Affiliation(s)
- Shafiul Alam
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
| | - Hitoshi Suzuki
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan; Centre for Nano Materials and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
| | - Toshifumi Tsukahara
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
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