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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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Amireddy N, Dulam V, Kaul S, Pakkiri R, Kalivendi SV. The mitochondrial uncoupling effects of nitazoxanide enhances cellular autophagy and promotes the clearance of α-synuclein: Potential role of AMPK-JNK pathway. Cell Signal 2023:110769. [PMID: 37315747 DOI: 10.1016/j.cellsig.2023.110769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/26/2023] [Accepted: 06/11/2023] [Indexed: 06/16/2023]
Abstract
Upregulation and aggregation of the pre-synaptic protein, α-synuclein plays a key role in Parkinson's disease (PD) and mitochondrial dysfunction was surmised to be an upstream event in the disease pathogenesis. Emerging reports identified the role of nitazoxanide (NTZ), an anti-helminth drug, in enhancing mitochondrial oxygen consumption rate (OCR) and autophagy. In the present study, we have examined the mitochondrial effects of NTZ in mediating cellular autophagy and subsequent clearance of both endogenous and pre-formed aggregates of α-synuclein in cellular model of PD. Our results demonstrate that the mitochondrial uncoupling effects of NTZ results in the activation of AMPK and JNK, which in-turn leads to the enhancement of cellular autophagy. Also,1-methyl-4-phenylpyridinium (MPP+) mediated decrease in autophagic flux with a concomitant increase in the α-synuclein levels were ameliorated in cells treated with NTZ. However, in cells lacking functional mitochondria (ρ0 cells), NTZ did not mitigate MPP+ mediated alterations in the autophagic clearance of α-synuclein, indicating that the mitochondrial effects of NTZ play a crucial role in the clearance of α-synuclein by autophagy. Also, the ability of AMPK inhibitor, compound C, in abrogating NTZ mediated enhancement in the autophagic flux and α-synuclein clearance highlight the pivotal role of AMPK in NTZ mediated autophagy. Further, NTZ per se enhanced the clearance of preformed α-synuclein aggregates that were exogenously added to the cells. Overall, the results of our present study suggest that NTZ activates macroautophagy in cells due to its uncoupling effects on mitochondrial respiration via activation of AMPK-JNK pathway resulting in the clearance of both endogenous and pre-formed α-synuclein aggregates. As NTZ happens to possess good bioavailability and safety profile, considering this drug for PD based on its mitochondrial uncoupling and autophagy enhancing properties for mitigating mitochondrial reactive oxygen species (ROS) and α-synuclein toxicity appears to be a promising therapeutic option.
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Affiliation(s)
- Niharika Amireddy
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Vandana Dulam
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India
| | - Shweta Kaul
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rajeswari Pakkiri
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India
| | - Shasi V Kalivendi
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Lee K, Yu D, Hyung D, Cho SY, Park C. ASpediaFI: Functional Interaction Analysis of Alternative Splicing Events. GENOMICS, PROTEOMICS & BIOINFORMATICS 2022; 20:466-482. [PMID: 35085775 PMCID: PMC9801047 DOI: 10.1016/j.gpb.2021.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 10/15/2021] [Accepted: 11/01/2021] [Indexed: 01/26/2023]
Abstract
Alternative splicing (AS) regulates biological processes governing phenotypes and diseases. Differential AS (DAS) gene test methods have been developed to investigate important exonic expression from high-throughput datasets. However, the DAS events extracted using statistical tests are insufficient to delineate relevant biological processes. In this study, we developed a novel application, Alternative Splicing Encyclopedia: Functional Interaction (ASpediaFI), to systemically identify DAS events and co-regulated genes and pathways. ASpediaFI establishes a heterogeneous interaction network of genes and their feature nodes (i.e., AS events and pathways) connected by co-expression or pathway gene set knowledge. Next, ASpediaFI explores the interaction network using the random walk with restart algorithm and interrogates the proximity from a query gene set. Finally, ASpediaFI extracts significant AS events, genes, and pathways. To evaluate the performance of our method, we simulated RNA sequencing (RNA-seq) datasets to consider various conditions of sequencing depth and sample size. The performance was compared with that of other methods. Additionally, we analyzed three public datasets of cancer patients or cell lines to evaluate how well ASpediaFI detects biologically relevant candidates. ASpediaFI exhibits strong performance in both simulated and public datasets. Our integrative approach reveals that DAS events that recognize a global co-expression network and relevant pathways determine the functional importance of spliced genes in the subnetwork. ASpediaFI is publicly available at https://bioconductor.org/packages/ASpediaFI.
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Thonda S, Vinnakota RL, Kona SV, Kalivendi SV. Identification of RBMX as a splicing regulator in Parkinsonian mimetic induced alternative splicing of α-synuclein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194825. [PMID: 35577270 DOI: 10.1016/j.bbagrm.2022.194825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/28/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
α-Synuclein (α-syn) plays a precipitating role in Parkinson's disease (PD) due to its tendency to form oligomers and fibrils. The presence of smaller isoforms of α-syn was widely noticed in the affected brain regions of PD patients. 112-synuclein (112-syn) which lacks exon-5, possess enhanced aggregation propensity and forms intracellular inclusions. However, the factors responsible for the skipping of exon-5 are not completely understood. In this context, we aimed to identity the cis & trans-acting elements governing alternative splicing (AS) events by the Parkinsonian agent (MPP+) using minigene constructs. Minigene-I and -II were constructed by pruning the intron-4 and -5 regions respectively without altering the branch point adenosine to preserve splicing machinery. Also, chimeric minigenes were engineered by replacing either 5' (Mini-III) or 3' (Mini-IV) flanking intronic regions of exon-5 with other intronic regions (intron-3 and -2) that are not responsive to MPP+ induced splicing. While all the above minigenes exhibited MPP+-induced skipping of exon-5, Minigene-III did not generate the spliced product indicating that the 5' flanking intronic region (316 bp) of exon-5 possess cis-acting elements responsible for oxidant-induced alternative splicing. RNA-Binding Protein Database (RBDP) analysis revealed the presence of four putative RNA binding proteins (RBPs), namely, RBMX, MBNL1, KHDRBS3 and SFRS1 that may bind to the 316 bp region of intron-4and their expression was substantially reduced following MPP+ treatment. Further, overexpression of RBMX mitigated MPP+-induced generation of 112-syn and also reduced intracellular α-syn aggregates. Overall, our study identified the pivotal role of the splicing regulator, RBMX, in the pathophysiology of PD.
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Affiliation(s)
- Swaroop Thonda
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Ravali L Vinnakota
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Swathi V Kona
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shasi V Kalivendi
- Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad 500007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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Chang C, Liu JW, Chen BC, Jiang ZS, Tu CT, Su CH, Yang HH, Liu ZQ, Deng YC, Chen CY, Tsai ST, Lin SZ, Chiou TW. Transplantation of Adipose-Derived Stem Cells Alleviates Striatal Degeneration in a Transgenic Mouse Model for Multiple System Atrophy. Cell Transplant 2021; 29:963689720960185. [PMID: 33028107 PMCID: PMC7784590 DOI: 10.1177/0963689720960185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Patients with multiple system atrophy (MSA), a progressive neurodegenerative disorder of adult onset, were found less than 9 years of life expectancy after onset. The disorders include bradykinesia and rigidity commonly seen in Parkinsonism disease and additional signs such as autonomic dysfunction, ataxia, or dementia. In clinical treatments, MSA poorly responds to levodopa, the drug used to remedy Parkinsonism disease. The exact cause of MSA is still unknown, and exploring a therapeutic solution to MSA remains critical. A transgenic mouse model was established to study the feasibility of human adipose-derived stem cell (ADSC) therapy in vivo. The human ADSCs were transplanted into the striatum of transgenic mice via intracerebral injection. As compared with sham control, we reported significantly enhanced rotarod performance of transgenic mice treated with ADSC at an effective dose, 2 × 105 ADSCs/mouse. Our ex vivo feasibility study supported that intracerebral transplantation of ADSC might alleviate striatal degeneration in MSA transgenic mouse model by improving the nigrostriatal pathway for dopamine, activating autophagy for α-synuclein clearance, decreasing inflammatory signal, and further cell apoptosis, improving myelination and cell survival at caudate-putamen.
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Affiliation(s)
- Christine Chang
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Jen-Wei Liu
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Bo Cheng Chen
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Zhe Sheng Jiang
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Chi Tang Tu
- Taiwan Mitochondrion Applied Technology Co., Ltd., Hsinchu, Taiwan, R.O.C
| | - Che Hung Su
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Hsin Han Yang
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Zong Qi Liu
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Yu Chen Deng
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Chih Yu Chen
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
| | - Sheng-Tzung Tsai
- Department of Neurosurgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, R.O.C.,Institute of Medical Science, Tzu Chi University, Hualien, Taiwan, R.O.C
| | - Shinn Zong Lin
- Department of Neurosurgery, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, R.O.C
| | - Tzyy-Wen Chiou
- Department of Life Science and Graduate Institute of Biotechnology, 63373National Dong Hwa University, Hualien, Taiwan, R.O.C
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Larsen K, Bæk R, Sahin C, Kjær L, Christiansen G, Nielsen J, Farajzadeh L, Otzen DE. Molecular characteristics of porcine alpha-synuclein splicing variants. Biochimie 2020; 180:121-133. [PMID: 33152422 DOI: 10.1016/j.biochi.2020.10.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 10/05/2020] [Accepted: 10/30/2020] [Indexed: 12/15/2022]
Abstract
Alpha-synuclein (α-syn) is a 140 amino acid, intrinsically disordered protein with a potential role in neurotransmitter vesicle release. The protein is natively unfolded under physiological conditions, and is expressed predominantly in neural tissue. α-syn is associated with neuropathological conditions in Parkinson's disease, where the protein misfolds into oligomers and fibrils resulting in aggregates in Lewy bodies. Here we report the molecular cloning of SNCA cDNA encoding porcine α-syn and transcript variants hereof. Six transcripts coding for porcine α-syn are presented in the report, of which three result from exon skipping, generating in-frame splicing of coding exons 3 and 5. The splicing pattern of these alternative spliced variants is conserved between human and pig. All the observed in-frame deletions yield significantly shorter α-syn proteins compared with the 140 amino acid full-length protein. Expression analysis performed by real-time quantitative RT-PCR revealed a differential expression of the six transcript splicing variants in different pig organs and tissues. Common for all splicing variants, a very high transcript expression was detected in brain tissues and in spinal cord and very low or no expression outside the central nervous system. The porcine α-syn protein demonstrated markedly different biophysical characteristics compared with its human counterpart. No fibrillation of porcine α-syn was observed with the pig wild-type α-syn and A30P α-syn, and both variants show significantly reduced ability to bind to lipid vesicles. Overexpression of mutated porcine α-syn might recapitulate the human PD pathogenesis and lead to the identification of genetic modifiers of the disease.
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Affiliation(s)
- Knud Larsen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, DK-8000, Aarhus C, Denmark.
| | - Rikke Bæk
- Department of Clinical Immunology, Aalborg University Hospital, Urbansgade 32, DK-9000, Aalborg, Denmark.
| | - Cagla Sahin
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK-8000, Aarhus C, Denmark.
| | - Lars Kjær
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK-8000, Aarhus C, Denmark.
| | - Gunna Christiansen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, DK-8000, Aarhus C, Denmark.
| | - Janni Nielsen
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK-8000, Aarhus C, Denmark.
| | - Leila Farajzadeh
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, DK-8000, Aarhus C, Denmark.
| | - Daniel E Otzen
- Interdisciplinary Nanoscience Center and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK-8000, Aarhus C, Denmark.
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Chaudhry ZL, Klenja D, Janjua N, Cami-Kobeci G, Ahmed BY. COVID-19 and Parkinson's Disease: Shared Inflammatory Pathways Under Oxidative Stress. Brain Sci 2020; 10:brainsci10110807. [PMID: 33142819 PMCID: PMC7693814 DOI: 10.3390/brainsci10110807] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 12/20/2022] Open
Abstract
The current coronavirus pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a serious global health crisis. It is a major concern for individuals living with chronic disorders such as Parkinson’s disease (PD). Increasing evidence suggests an involvement of oxidative stress and contribution of NFκB in the development of both COVID-19 and PD. Although, it is early to identify if SARS-CoV-2 led infection enhances PD complications, it is likely that oxidative stress may exacerbate PD progression in COVID-19 affected individuals and/or vice versa. In the current study, we sought to investigate whether NFκB-associated inflammatory pathways following oxidative stress in SARS-CoV-2 and PD patients are correlated. Toward this goal, we have integrated bioinformatics analysis obtained from Basic Local Alignment Search Tool of Protein Database (BLASTP) search for similarities of SARS-CoV-2 proteins against human proteome, literature review, and laboratory data obtained in a human cell model of PD. A Parkinson’s like state was created in 6-hydroxydopamine (6OHDA)-induced differentiated dopamine-containing neurons (dDCNs) obtained from an immortalized human neural progenitor cell line derived from the ventral mesencephalon region of the brain (ReNVM). The results indicated that SARS-CoV-2 infection and 6OHDA-induced toxicity triggered stimulation of caspases-2, -3 and -8 via the NFκB pathway resulting in the death of dDCNs. Furthermore, specific inhibitors for NFκB and studied caspases reduced the death of stressed dDCNs. The findings suggest that knowledge of the selective inhibition of caspases and NFκB activation may contribute to the development of potential therapeutic approaches for the treatment of COVID-19 and PD.
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Affiliation(s)
- Zahara L. Chaudhry
- Institute of Biomedical & Environmental Science and Technology, School of Life Sciences, Faculty of Creative Arts, Technologies & Science, University Square, University of Bedfordshire, Luton LU1 3JU, UK; (Z.L.C.); (G.C.-K.)
| | - Donika Klenja
- School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, UK;
| | - Najma Janjua
- Faculty of Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan;
| | - Gerta Cami-Kobeci
- Institute of Biomedical & Environmental Science and Technology, School of Life Sciences, Faculty of Creative Arts, Technologies & Science, University Square, University of Bedfordshire, Luton LU1 3JU, UK; (Z.L.C.); (G.C.-K.)
| | - Bushra Y. Ahmed
- Institute of Biomedical & Environmental Science and Technology, School of Life Sciences, Faculty of Creative Arts, Technologies & Science, University Square, University of Bedfordshire, Luton LU1 3JU, UK; (Z.L.C.); (G.C.-K.)
- Correspondence:
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Tseng E, Rowell WJ, Glenn OC, Hon T, Barrera J, Kujawa S, Chiba-Falek O. The Landscape of SNCA Transcripts Across Synucleinopathies: New Insights From Long Reads Sequencing Analysis. Front Genet 2019; 10:584. [PMID: 31338105 PMCID: PMC6629766 DOI: 10.3389/fgene.2019.00584] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 06/04/2019] [Indexed: 11/21/2022] Open
Abstract
Dysregulation of alpha-synuclein expression has been implicated in the pathogenesis of synucleinopathies, in particular Parkinson's Disease (PD) and Dementia with Lewy bodies (DLB). Previous studies have shown that the alternatively spliced isoforms of the SNCA gene are differentially expressed in different parts of the brain for PD and DLB patients. Similarly, SNCA isoforms with skipped exons can have a functional impact on the protein domains. The large intronic region of the SNCA gene was also shown to harbor structural variants that affect transcriptional levels. Here, we apply the first study of using long read sequencing with targeted capture of both the gDNA and cDNA of the SNCA gene in brain tissues of PD, DLB, and control samples using the PacBio Sequel system. The targeted full-length cDNA (Iso-Seq) data confirmed complex usage of known alternative start sites and variable 3' UTR lengths, as well as novel 5' starts and 3' ends not previously described. The targeted gDNA data allowed phasing of up to 81% of the ~114 kb SNCA region, with the longest phased block exceeding 54 kb. We demonstrate that long gDNA and cDNA reads have the potential to reveal long-range information not previously accessible using traditional sequencing methods. This approach has a potential impact in studying disease risk genes such as SNCA, providing new insights into the genetic etiologies, including perturbations to the landscape the gene transcripts, of human complex diseases such as synucleinopathies.
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Affiliation(s)
| | | | - Omolara-Chinue Glenn
- Department of Neurology, Duke University Medical Center, Durham, NC, United States
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, United States
| | - Ting Hon
- Pacific Biosciences, Menlo Park, CA, United States
| | - Julio Barrera
- Department of Neurology, Duke University Medical Center, Durham, NC, United States
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, United States
| | - Steve Kujawa
- Pacific Biosciences, Menlo Park, CA, United States
| | - Ornit Chiba-Falek
- Department of Neurology, Duke University Medical Center, Durham, NC, United States
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, United States
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Vinnakota RL, Yedlapudi D, Manda KM, Bhamidipati K, Bommakanti KT, RangaLakshmi GS, Kalivendi SV. Identification of an Alternatively Spliced α-Synuclein Isoform That Generates a 41-Amino Acid N-Terminal Truncated Peptide, 41-syn: Role in Dopamine Homeostasis. ACS Chem Neurosci 2018; 9:2948-2958. [PMID: 29996045 DOI: 10.1021/acschemneuro.8b00140] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The presynaptic protein, α-synuclein (α-syn), has been shown to play a crucial role in multiple neurodegenerative diseases, such as Parkinson's disease (PD), Alzheimer's disease (AD), and dementia with Lewy bodies (DLB). The three major domains of α-syn protein were shown to govern its membrane interaction, protein fibrillation, and chaperone activity. So far, four different alternatively spliced isoforms of α-syn, which lack either exon 3 (syn-126) or exon 5 (syn-112) or both (syn-98) resulting in altered function of the proteins, have been identified. In the present study, we have identified the smallest isoform of α-syn due to the skipping of exons 3 and 4 generating a 238 bp transcript. Due to the presence of a premature stop codon, the 238 bp transcript generated a 41 aa N-terminal peptide instead of the 78 aa protein, which is secreted into the extracellular medium when overexpressed in cells. The presence of 41-syn was initially noticed in the substantia nigra of PD autopsy tissues, as well as in cells undergoing oxidative stress. In vitro studies inferred that 41-syn neither aggregates nor alters the aggregation propensity of either WT or 112-syn. Overexpression of 41-syn or treatment of cells with 41-syn peptide did not affect cell viability. However, PC-12 cells treated with 41-syn exhibited a time and dose dependent enhancement in the cellular uptake of dopamine. Based on the physiological role of the N-terminal region of α-syn in modulating membrane trafficking events, we believe that the identification of 41-syn may provide novel impetus in unraveling the physiological basis of alternative splicing events in governing PD pathophysiology.
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Affiliation(s)
| | | | | | | | | | - G Sree RangaLakshmi
- Department of Neurology, Osmania General Hospital, Afzal Gunj, Hyderabad, 500012 TS, India
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Gámez-Valero A, Beyer K. Alternative Splicing of Alpha- and Beta-Synuclein Genes Plays Differential Roles in Synucleinopathies. Genes (Basel) 2018; 9:genes9020063. [PMID: 29370097 PMCID: PMC5852559 DOI: 10.3390/genes9020063] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 11/16/2022] Open
Abstract
The synuclein family is composed of three members, two of which, α- and β-synuclein, play a major role in the development of synucleinopathies, including Parkinson’s disease (PD) as most important movement disorder, dementia with Lewy bodies (DLB) as the second most frequent cause of dementia after Alzheimer’s disease and multiple system atrophy. Whereas abnormal oligomerization and fibrillation of α-synuclein are now well recognized as initial steps in the development of synucleinopathies, β-synuclein is thought to be a natural α-synuclein anti-aggregant. α-synuclein is encoded by the SNCA gene, and β-synuclein by SNCB. Both genes are homologous and undergo complex splicing events. On one hand, in-frame splicing of coding exons gives rise to at least three shorter transcripts, and the functional properties of the corresponding protein isoforms are different. Another type of alternative splicing is the alternative inclusion of at least four initial exons in the case of SNCA, and two in the case of SNCB. Finally, different lengths of 3’ untranslated regions have been also reported for both genes. SNCB only expresses in the brain, but some of the numerous SNCA transcripts are also brain-specific. With the present article, we aim to provide a systematic review of disease related changes in the differential expression of the various SNCA and SNCB transcript variants in brain, blood, and non-neuronal tissue of synucleinopathies, but especially PD and DLB as major neurodegenerative disorders.
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Affiliation(s)
- Ana Gámez-Valero
- Department of Pathology, Germans Trias i Pujol Research Institute, Badalona, 08916 Barcelona, Spain.
| | - Katrin Beyer
- Department of Pathology, Germans Trias i Pujol Research Institute, Badalona, 08916 Barcelona, Spain.
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Amireddy N, Puttapaka SN, Vinnakota RL, Ravuri HG, Thonda S, Kalivendi SV. The unintended mitochondrial uncoupling effects of the FDA-approved anti-helminth drug nitazoxanide mitigates experimental parkinsonism in mice. J Biol Chem 2017; 292:15731-15743. [PMID: 28798236 DOI: 10.1074/jbc.m117.791863] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/31/2017] [Indexed: 01/04/2023] Open
Abstract
Mitochondria play a primary role in the pathophysiology of Parkinson's disease (PD), and small molecules that counteract the initial stages of disease may offer therapeutic benefit. In this regard, we have examined whether the off-target effects of the Food and Drug Administration (FDA)-approved anti-helminth drug nitazoxanide (NTZ) on mitochondrial respiration could possess any therapeutic potential for PD. Results indicate that MPP+-induced loss in oxygen consumption rate (OCR) and ATP production by mitochondria were ameliorated by NTZ in real time by virtue of its mild uncoupling effect. Pretreatment of cells with NTZ mitigated MPP+-induced loss in mitochondrial OCR and reactive oxygen species (ROS). Similarly, addition of NTZ to cells pretreated with MPP+ could reverse block in mitochondrial OCR and reactive oxygen species induced by MPP+ in real time. The observed effects of NTZ were found to be transient and reversible as removal of NTZ from incubation medium restored the mitochondrial respiration to that of controls. Apoptosis induced by MPP+ was ameliorated by NTZ in a dose-dependent manner. In vivo results demonstrated that oral administration of NTZ (50 mg/kg) in an acute MPTP mouse model of PD conferred significant protection against the loss of tyrosine hydroxylase (TH)-positive neurons of substantia nigra. Based on the above observations we believe that repurposing of NTZ for PD may offer therapeutic benefit.
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Affiliation(s)
| | | | | | - Halley G Ravuri
- Pharmacology and Toxicology, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad - 500 007, Telangana State, India
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Deregulation of α-synuclein in Parkinson's disease: Insight from epigenetic structure and transcriptional regulation of SNCA. Prog Neurobiol 2017; 154:21-36. [PMID: 28445713 DOI: 10.1016/j.pneurobio.2017.04.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/19/2023]
Abstract
Understanding regulation of α-synuclein has long been a central focus for Parkinson's disease (PD) researchers. Accumulation of this protein in the Lewy body or neurites, mutations in the coding region of the gene and strong association of α-synuclein encoding gene multiplication (duplication/triplication) with familial form of PD have indicated the importance of this molecule in pathogenesis of the disease. Several years of research identified many potential faulty pathways associated with accumulation of α-synuclein inside dopaminergic neurons and its transmission to neighboring ones. Concurrently, an appreciable body of research is growing to understand the epigenetic and genetic deregulation of α-synuclein that might contribute to the disease pathology. Completion of the ENCODE (Encyclopedia of DNA Elements) project and recent advancement made in the epigenetic and trans factor mediated regulation of each gene, has tremendously accelerated the need to carefully understand the epigenetic structure of the gene (SNCA) encoding α-synuclein protein in order to decipher the regulation and contribution of α-synuclein to the pathogenesis of PD. We have also analyzed the detailed epigenetic structure of this gene with knowledge from ENCODE database, which may open new avenues in α-synuclein research. Interestingly, we have found that the gene contains several transcriptionally activate histone modifications and associated potential transcription factor binding sites in the non-coding areas that strongly suggest alternative regulatory pathways. Altogether this review will provide interesting insight of α-synuclein gene regulation from epigenetic, genetic and post-transcriptional perspectives and their potential implication in the PD pathogenesis.
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Jęśko H, Lenkiewicz AM, Adamczyk A. Treatments and compositions targeting α-synuclein: a patent review (2010-2016). Expert Opin Ther Pat 2016; 27:427-438. [DOI: 10.1080/13543776.2017.1261112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Henryk Jęśko
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Anna M. Lenkiewicz
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Agata Adamczyk
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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15
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Ghosh D, Mehra S, Sahay S, Singh PK, Maji SK. α-synuclein aggregation and its modulation. Int J Biol Macromol 2016; 100:37-54. [PMID: 27737778 DOI: 10.1016/j.ijbiomac.2016.10.021] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 10/06/2016] [Accepted: 10/09/2016] [Indexed: 12/20/2022]
Abstract
Parkinson's disease (PD) is a neurological disorder marked by the presence of cytoplasmic inclusions, Lewy bodies (LBs) and Lewy neurites (LNs) as well as the degeneration of dopamine producing neurons in the substantia nigra region of the brain. The LBs and LNs in PD are mainly composed of aggregated form of a presynaptic protein, α-synuclein (α-Syn). However, the mechanisms of α-Syn aggregation and actual aggregated species responsible for the degeneration of dopaminergic neurons have not yet been resolved. Despite the fact that α-Syn aggregation in LBs and LNs is crucial and mutations of α-Syn are associated with early onset PD, it is really a challenging task to establish a correlation between α-Syn aggregation rate and PD pathogenesis. Regardless of strong genetic contribution, PD is mostly sporadic and familial forms of the disease represent only a minor part (<10%) of all cases. The complexity in PD further increases due to the involvement of several cellular factors in the pathogenesis of the disease as well as the environmental factors associated with the risk of developing PD. Therefore, effect of these factors on α-Syn aggregation pathway and how these factors modulate the properties of wild type (WT) as well as mutated α-Syn should be collectively taken into account. The present review specifically provides an overview of recent research on α-Syn aggregation pathways and its modulation by several cellular factors potentially relevant to PD pathogenesis. We also briefly discuss about effect of environmental risk factors on α-Syn aggregation.
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Affiliation(s)
- Dhiman Ghosh
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, India.
| | - Surabhi Mehra
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, India
| | - Shruti Sahay
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, India.
| | - Pradeep K Singh
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, India
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Mumbai, Maharashtra, India.
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16
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Tagliafierro L, Chiba-Falek O. Up-regulation of SNCA gene expression: implications to synucleinopathies. Neurogenetics 2016; 17:145-57. [PMID: 26948950 DOI: 10.1007/s10048-016-0478-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/27/2016] [Indexed: 01/06/2023]
Abstract
Synucleinopathies are a group of neurodegenerative diseases that share a common pathological lesion of intracellular protein inclusions largely composed by aggregates of alpha-synuclein protein. Accumulating evidence, including genome wide association studies, has implicated alpha-synuclein (SNCA) gene in the etiology of synucleinopathies. However, the precise variants within SNCA gene that contribute to the sporadic forms of Parkinson's disease (PD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and other synucleinopathies and their molecular mechanisms of action remain elusive. It has been suggested that SNCA expression levels are critical for the development of these diseases. Here, we review several model systems that have been developed to advance the understanding of the role of SNCA expression levels in the etiology of synucleinopathies. We also describe different molecular mechanisms that regulate SNCA gene expression and discuss possible strategies for SNCA down-regulation as means for therapeutic approaches. Finally, we highlight some examples that underscore the relationships between the genetic association findings and the regulatory mechanisms of SNCA expression, which suggest that genetic variability in SNCA locus is directly responsible, at least in part, to the changes in gene expression and explain the reported associations of SNCA with synucleinopathies. Future studies utilizing induced pluripotent stem cells (iPSCs)-derived neuronal lines and genome editing by CRISPR/Cas9, will allow us to validate, characterize, and manipulate the effects of particular cis-genetic variants on SNCA expression. Moreover, this model system will enable us to compare different neuronal and glial lineages involved in synucleinopathies representing an attractive strategy to elucidate-common and specific-SNCA-genetic variants, regulatory mechanisms, and vulnerable expression levels underlying synucleinopathy spectrum disorders. This forthcoming knowledge will support the development of precision medicine for synucleinopathies.
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Affiliation(s)
- L Tagliafierro
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - O Chiba-Falek
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
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Brudek T, Winge K, Rasmussen NB, Bahl JMC, Tanassi J, Agander TK, Hyde TM, Pakkenberg B. Altered α-synuclein, parkin, and synphilin isoform levels in multiple system atrophy brains. J Neurochem 2015; 136:172-85. [DOI: 10.1111/jnc.13392] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 09/29/2015] [Indexed: 01/16/2023]
Affiliation(s)
- Tomasz Brudek
- Research Laboratory for Stereology and Neuroscience; Bispebjerg-Frederiksberg Hospital; University Hospital of Copenhagen; Copenhagen NV Denmark
- Bispebjerg Movement Disorders Biobank; Bispebjerg-Frederiksberg Hospital; University Hospital of Copenhagen; Copenhagen N Denmark
| | - Kristian Winge
- Department of Neurology; Bispebjerg-Frederiksberg Hospital; University Hospital of Copenhagen; Copenhagen NV Denmark
- Bispebjerg Movement Disorders Biobank; Bispebjerg-Frederiksberg Hospital; University Hospital of Copenhagen; Copenhagen N Denmark
| | - Nadja Bredo Rasmussen
- Research Laboratory for Stereology and Neuroscience; Bispebjerg-Frederiksberg Hospital; University Hospital of Copenhagen; Copenhagen NV Denmark
| | | | - Julia Tanassi
- Department of Autoimmunology and Biomarkers; Statens Serum Institut; Copenhagen S Denmark
| | | | - Thomas M. Hyde
- Lieber Institute for Brain Development; Johns Hopkins Medical Campus; Baltimore Maryland USA
- Department of Psychiatry and Behavioral Sciences; Johns Hopkins University School of Medicine; Baltimore Maryland USA
- Department of Neurology; Johns Hopkins University School of Medicine; Baltimore Maryland USA
| | - Bente Pakkenberg
- Research Laboratory for Stereology and Neuroscience; Bispebjerg-Frederiksberg Hospital; University Hospital of Copenhagen; Copenhagen NV Denmark
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18
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Splicing Regulation of Pro-Inflammatory Cytokines and Chemokines: At the Interface of the Neuroendocrine and Immune Systems. Biomolecules 2015; 5:2073-100. [PMID: 26371053 PMCID: PMC4598789 DOI: 10.3390/biom5032073] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/28/2015] [Indexed: 01/13/2023] Open
Abstract
Alternative splicing plays a key role in posttranscriptional regulation of gene expression, allowing a single gene to encode multiple protein isoforms. As such, alternative splicing amplifies the coding capacity of the genome enormously, generates protein diversity, and alters protein function. More than 90% of human genes undergo alternative splicing, and alternative splicing is especially prevalent in the nervous and immune systems, tissues where cells need to react swiftly and adapt to changes in the environment through carefully regulated mechanisms of cell differentiation, migration, targeting, and activation. Given its prevalence and complexity, this highly regulated mode of gene expression is prone to be affected by disease. In the following review, we look at how alternative splicing of signaling molecules—cytokines and their receptors—changes in different pathological conditions, from chronic inflammation to neurologic disorders, providing means of functional interaction between the immune and neuroendocrine systems. Switches in alternative splicing patterns can be very dynamic and can produce signaling molecules with distinct or antagonistic functions and localization to different subcellular compartments. This newly discovered link expands our understanding of the biology of immune and neuroendocrine cells, and has the potential to open new windows of opportunity for treatment of neurodegenerative disorders.
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Splicing: is there an alternative contribution to Parkinson's disease? Neurogenetics 2015; 16:245-63. [PMID: 25980689 PMCID: PMC4573652 DOI: 10.1007/s10048-015-0449-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/04/2015] [Indexed: 12/21/2022]
Abstract
Alternative splicing is a crucial mechanism of gene expression regulation that enormously increases the coding potential of our genome and represents an intermediate step between messenger RNA (mRNA) transcription and protein posttranslational modifications. Alternative splicing occupies a central position in the development and functions of the nervous system. Therefore, its deregulation frequently leads to several neurological human disorders. In the present review, we provide an updated overview on the impact of alternative splicing in Parkinson's disease (PD), the second most common neurodegenerative disorder worldwide. We will describe the alternative splicing of major PD-linked genes by collecting the current evidences about this intricate and not carefully explored aspect. Assessing the role of this mechanism on PD pathobiology may represent a central step toward an improved understanding of this complex disease.
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20
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Possible role of GABA-B receptor modulation in MPTP induced Parkinson's disease in rats. ACTA ACUST UNITED AC 2015; 67:211-7. [DOI: 10.1016/j.etp.2014.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 10/23/2014] [Accepted: 12/04/2014] [Indexed: 01/27/2023]
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21
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Chen J, Mills JD, Halliday GM, Janitz M. The role of transcriptional control in multiple system atrophy. Neurobiol Aging 2015; 36:394-400. [DOI: 10.1016/j.neurobiolaging.2014.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/29/2014] [Accepted: 08/12/2014] [Indexed: 12/15/2022]
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JNK inhibition of VMAT2 contributes to rotenone-induced oxidative stress and dopamine neuron death. Toxicology 2014; 328:75-81. [PMID: 25496994 DOI: 10.1016/j.tox.2014.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/27/2014] [Accepted: 12/06/2014] [Indexed: 02/06/2023]
Abstract
Treatment with rotenone, both in vitro and in vivo, is widely used to model dopamine neuron death in Parkinson's disease upon exposure to environmental neurotoxicants and pesticides. Mechanisms underlying rotenone neurotoxicity are still being defined. Our recent studies suggest that rotenone-induced dopamine neuron death involves microtubule destabilization, which leads to accumulation of cytosolic dopamine and consequently reactive oxygen species (ROS). Furthermore, the c-Jun N-terminal protein kinase (JNK) is required for rotenone-induced dopamine neuron death. Here we report that the neural specific JNK3 isoform of the JNKs, but not JNK1 or JNK2, is responsible for this neuron death in primary cultured dopamine neurons. Treatment with taxol, a microtubule stabilizing agent, attenuates rotenone-induced phosphorylation and presumably activation of JNK. This suggests that JNK is activated by microtubule destabilization upon rotenone exposure. Moreover, rotenone inhibits VMAT2 activity but not VMAT2 protein levels. Significantly, treatment with SP600125, a pharmacological inhibitor of JNKs, attenuates rotenone inhibition of VMAT2. Furthermore, decreased VMAT2 activity following in vitro incubation of recombinant JNK3 protein with purified mesencephalic synaptic vesicles suggests that JNK3 can inhibit VMAT2 activity. Together with our previous findings, these results suggest that rotenone induces dopamine neuron death through a series of sequential events including microtubule destabilization, JNK3 activation, VMAT2 inhibition, accumulation of cytosolic dopamine, and generation of ROS. Our data identify JNK3 as a novel regulator of VMAT2 activity.
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23
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Manda KM, Yedlapudi D, Korukonda S, Bojja S, Kalivendi SV. The chaperone-like activity of α-synuclein attenuates aggregation of its alternatively spliced isoform, 112-synuclein in vitro: plausible cross-talk between isoforms in protein aggregation. PLoS One 2014; 9:e98657. [PMID: 24892822 PMCID: PMC4043908 DOI: 10.1371/journal.pone.0098657] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/05/2014] [Indexed: 12/29/2022] Open
Abstract
Abnormal oligomerization and aggregation of α-synuclein (α-syn/WT-syn) has been shown to be a precipitating factor in the pathophysiology of Parkinson's disease (PD). Earlier observations on the induced-alternative splicing of α-syn by Parkinsonism mimetics as well as identification of region specific abnormalities in the transcript levels of 112-synclein (112-syn) in diseased subjects underscores the role of 112-syn in the pathophysiology of PD. In the present study, we sought to identify the aggregation potential of 112-syn in the presence or absence of WT-syn to predict its plausible role in protein aggregation events. Results demonstrate that unlike WT-syn, lack of 28 aa in the C-terminus results in the loss of chaperone-like activity with a concomitant gain in vulnerability to heat-induced aggregation and time-dependent fibrillation. The effects were dose and time-dependent and a significant aggregation of 112-syn was evident at as low as 45°C following 10 min of incubation. The heat-induced aggregates were found to be ill-defined structures and weakly positive towards Thioflavin-T (ThT) staining as compared to clearly distinguishable ThT positive extended fibrils resulting upon 24 h of incubation at 37°C. Further, the chaperone-like activity of WT-syn significantly attenuated heat-induced aggregation of 112-syn in a dose and time-dependent manner. On contrary, WT-syn synergistically enhanced fibrillation of 112-syn. Overall, the present findings highlight a plausible cross-talk between isoforms of α-syn and the relative abundance of these isoforms may dictate the nature and fate of protein aggregates.
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Affiliation(s)
- Krishna Madhuri Manda
- Centre for Academy of Scientific & Innovative Research, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
- Centre for Chemical Biology, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
| | - Deepthi Yedlapudi
- Centre for Chemical Biology, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
| | - Srikanth Korukonda
- Centre for Chemical Biology, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
| | - Sreedhar Bojja
- Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
| | - Shasi V. Kalivendi
- Centre for Academy of Scientific & Innovative Research, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
- Centre for Chemical Biology, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, Andhra Pradesh, India
- * E-mail:
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24
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Schlaudraff F, Gründemann J, Fauler M, Dragicevic E, Hardy J, Liss B. Orchestrated increase of dopamine and PARK mRNAs but not miR-133b in dopamine neurons in Parkinson's disease. Neurobiol Aging 2014; 35:2302-15. [PMID: 24742361 PMCID: PMC4099518 DOI: 10.1016/j.neurobiolaging.2014.03.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 02/27/2014] [Accepted: 03/14/2014] [Indexed: 01/25/2023]
Abstract
Progressive loss of substantia nigra dopamine neurons (SN DA) is a hallmark of aging and of Parkinson's disease (PD). Mutations in PARK genes cause familial PD forms. Increased expression of alpha-synuclein (PARK4) is a disease-triggering event in familial PD and also observed in SN DA neurons in sporadic PD but related transcriptional changes are unknown. With optimized single-cell quantitative real-time polymerase chain reaction analysis, we compared messenger RNA and microRNA levels in SN DA neurons from sporadic PD patients and controls. Non-optimally matched donor ages and RNA integrities are common problems when analyzing human samples. We dissected the influence of distinct ages and RNA integrities of our samples by applying a specifically-optimized, linear-mixed-effects model to quantitative real-time polymerase chain reaction-data. We identified that elevated alpha-synuclein messenger RNA levels in SN DA neurons of human PD brains were positively correlated with corresponding elevated levels of mRNAs for functional compensation of progressive SN DA loss and for enhanced proteasomal (PARK5/UCHL1) and lysosomal (PARK9/ATPase13A2) function, possibly counteracting alpha-synuclein toxicity. In contrast, microRNA miR-133b levels, previously implicated in transcriptional dysregulation in PD, were not altered in SN DA neurons in PD.
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Affiliation(s)
- Falk Schlaudraff
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Jan Gründemann
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Michael Fauler
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Elena Dragicevic
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - John Hardy
- Department of Molecular Neuroscience and Reta Lila Weston Laboratories, Institute of Neurology, London, UK
| | - Birgit Liss
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany.
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25
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Splice isoform and pharmacological studies reveal that sterol depletion relocalizes α-synuclein and enhances its toxicity. Proc Natl Acad Sci U S A 2014; 111:3014-9. [PMID: 24516169 DOI: 10.1073/pnas.1324209111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synucleinopathies are neurodegenerative diseases associated with toxicity of the lipid-binding protein α-synuclein (α-syn). When expressed in yeast, α-syn associates with membranes at the endoplasmic reticulum and traffics with vesicles out to the plasma membrane. At higher levels it elicits a number of phenotypes, including blocking vesicle trafficking. The expression of α-syn splice isoforms varies with disease, but how these isoforms affect protein function is unknown. We investigated two of the most abundant isoforms, resulting in deletion of exon four (α-synΔ4) or exon six (α-synΔ6). α-SynΔ4, missing part of the lipid-binding domain, had reduced toxicity and membrane binding. α-SynΔ6, missing part of the protein-protein interaction domain, had reduced toxicity but no reduction in membrane binding. To compare the mechanism by which the splice isoforms exert toxicity, equally toxic strains were probed with genetic modifiers of α-syn-induced toxicity. Most modifiers equally altered the toxicity induced by the splice isoforms and full-length α-syn (α-synFL). However, the splice isoform strains responded differently to a sterol-binding protein, leading us to examine the effect of sterols on α-syn-induced toxicity. Upon inhibition of sterol synthesis, α-synFL and α-synΔ6, but not α-synΔ4, showed decreased plasma membrane association, increased vesicular association, and increased cellular toxicity. Thus, higher membrane sterol concentrations favor plasma membrane binding of α-synFL and α-synΔ6 and may be protective of synucleinopathy progression. Given the common use of cholesterol-reducing statins and these potential effects on membrane binding proteins, further investigation of how sterol concentration and α-syn splice isoforms affect vesicular trafficking in synucleinopathies is warranted.
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26
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Ryan BJ, Lourenço-Venda LL, Crabtree MJ, Hale AB, Channon KM, Wade-Martins R. α-Synuclein and mitochondrial bioenergetics regulate tetrahydrobiopterin levels in a human dopaminergic model of Parkinson disease. Free Radic Biol Med 2014; 67:58-68. [PMID: 24148766 PMCID: PMC5238936 DOI: 10.1016/j.freeradbiomed.2013.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 10/03/2013] [Accepted: 10/07/2013] [Indexed: 11/26/2022]
Abstract
Parkinson disease (PD) is a multifactorial disease resulting in preferential death of the dopaminergic neurons in the substantia nigra. Studies of PD-linked genes and toxin-induced models of PD have implicated mitochondrial dysfunction, oxidative stress, and the misfolding and aggregation of α-synuclein (α-syn) as key factors in disease initiation and progression. Many of these features of PD may be modeled in cells or animal models using the neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)). Reducing oxidative stress and nitric oxide synthase (NOS) activity has been shown to be protective in cell or animal models of MPP(+) toxicity. We have previously demonstrated that siRNA-mediated knockdown of α-syn lowers the activity of both dopamine transporter and NOS activity and protects dopaminergic neuron-like cells from MPP(+) toxicity. Here, we demonstrate that α-syn knockdown and modulators of oxidative stress/NOS activation protect cells from MPP(+)-induced toxicity via postmitochondrial mechanisms rather than by a rescue of the decrease in mitochondrial oxidative phosphorylation caused by MPP(+) exposure. We demonstrate that MPP(+) significantly decreases the synthesis of the antioxidant and obligate cofactor of NOS and TH tetrahydrobiopterin (BH4) through decreased cellular GTP/ATP levels. Furthermore, we demonstrate that RNAi knockdown of α-syn results in a nearly twofold increase in GTP cyclohydrolase I activity and a concomitant increase in basal BH4 levels. Together, these results demonstrate that both mitochondrial activity and α-syn play roles in modulating cellular BH4 levels.
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Affiliation(s)
- Brent J Ryan
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Lara L Lourenço-Venda
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Mark J Crabtree
- British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Ashley B Hale
- British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Keith M Channon
- British Heart Foundation Centre of Research Excellence, Division of Cardiovascular Medicine, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK.
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27
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Perfeito R, Cunha-Oliveira T, Rego AC. Reprint of: revisiting oxidative stress and mitochondrial dysfunction in the pathogenesis of Parkinson disease-resemblance to the effect of amphetamine drugs of abuse. Free Radic Biol Med 2013; 62:186-201. [PMID: 23743292 DOI: 10.1016/j.freeradbiomed.2013.05.042] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 12/15/2022]
Abstract
Parkinson disease (PD) is a chronic and progressive neurological disease associated with a loss of dopaminergic neurons. In most cases the disease is sporadic but genetically inherited cases also exist. One of the major pathological features of PD is the presence of aggregates that localize in neuronal cytoplasm as Lewy bodies, mainly composed of α-synuclein (α-syn) and ubiquitin. The selective degeneration of dopaminergic neurons suggests that dopamine itself may contribute to the neurodegenerative process in PD. Furthermore, mitochondrial dysfunction and oxidative stress constitute key pathogenic events of this disorder. Thus, in this review we give an actual perspective to classical pathways involving these two mechanisms of neurodegeneration, including the role of dopamine in sporadic and familial PD, as well as in the case of abuse of amphetamine-type drugs. Mutations in genes related to familial PD causing autosomal dominant or recessive forms may also have crucial effects on mitochondrial morphology, function, and oxidative stress. Environmental factors, such as MPTP and rotenone, have been reported to induce selective degeneration of the nigrostriatal pathways leading to α-syn-positive inclusions, possibly by inhibiting mitochondrial complex I of the respiratory chain and subsequently increasing oxidative stress. Recently, increased risk for PD was found in amphetamine users. Amphetamine drugs have effects similar to those of other environmental factors for PD, because long-term exposure to these drugs leads to dopamine depletion. Moreover, amphetamine neurotoxicity involves α-syn aggregation, mitochondrial dysfunction, and oxidative stress. Therefore, dopamine and related oxidative stress, as well as mitochondrial dysfunction, seem to be common links between PD and amphetamine neurotoxicity.
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Affiliation(s)
- Rita Perfeito
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Teresa Cunha-Oliveira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ana Cristina Rego
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal.
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28
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Schmid AW, Fauvet B, Moniatte M, Lashuel HA. Alpha-synuclein post-translational modifications as potential biomarkers for Parkinson disease and other synucleinopathies. Mol Cell Proteomics 2013; 12:3543-58. [PMID: 23966418 DOI: 10.1074/mcp.r113.032730] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The development of novel therapies against neurodegenerative disorders requires the ability to detect their early, presymptomatic manifestations in order to enable treatment before irreversible cellular damage occurs. Precocious signs indicative of neurodegeneration include characteristic changes in certain protein levels, which can be used as diagnostic biomarkers when they can be detected in fluids such as blood plasma or cerebrospinal fluid. In the case of synucleinopathies, cerebrospinal alpha-synuclein (α-syn) has attracted great interest as a potential biomarker; however, there is ongoing debate regarding the association between cerebrospinal α-syn levels and neurodegeneration in Parkinson disease and synucleinopathies. Post-translational modifications (PTMs) have emerged as important determinants of α-syn's physiological and pathological functions. Several PTMs are enriched within Lewy bodies and exist at higher levels in α-synucleinopathy brains, suggesting that certain modified forms of α-syn might be more relevant biomarkers than the total α-syn levels. However, the quantification of PTMs in bodily fluids poses several challenges. This review describes the limitations of current immunoassay-based α-syn quantification methods and highlights how these limitations can be overcome using novel mass-spectrometry-based assays. In addition, we describe how advances in chemical synthesis, which have enabled the preparation of α-syn proteins that are site-specifically modified at single or multiple residues, can facilitate the development of more accurate assays for detecting and quantifying α-syn PTMs in health and disease.
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Affiliation(s)
- Adrien W Schmid
- Proteomics Core Facility, School of Life Sciences, Station 19, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Rotenone upregulates alpha-synuclein and myocyte enhancer factor 2D independently from lysosomal degradation inhibition. BIOMED RESEARCH INTERNATIONAL 2013; 2013:846725. [PMID: 23984410 PMCID: PMC3745903 DOI: 10.1155/2013/846725] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/18/2013] [Accepted: 07/02/2013] [Indexed: 12/21/2022]
Abstract
Dysfunctions of chaperone-mediated autophagy (CMA), the main catabolic pathway for alpha-synuclein, have been linked to the pathogenesis of Parkinson's disease (PD). Since till now there is limited information on how PD-related toxins may affect CMA, in this study we explored the effect of mitochondrial complex I inhibitor rotenone on CMA substrates, alpha-synuclein and MEF2D, and effectors, lamp2A and hsc70, in a human dopaminergic neuroblastoma SH-SY5Y cell line. Rotenone induced an upregulation of alpha-synuclein and MEF2D protein levels through the stimulation of their de novo synthesis rather than through a reduction of their CMA-mediated degradation. Moreover, increased MEF2D transcription resulted in higher nuclear protein levels that exert a protective role against mitochondrial dysfunction and oxidative stress. These results were compared with those obtained after lysosome inhibition with ammonium chloride. As expected, this toxin induced the cytosolic accumulation of both alpha-synuclein and MEF2D proteins, as the result of the inhibition of their lysosome-mediated degradation, while, differently from rotenone, ammonium chloride decreased MEF2D nuclear levels through the downregulation of its transcription, thus reducing its protective function. These results highlight that rotenone affects alpha-synuclein and MEF2D protein levels through a mechanism independent from lysosomal degradation inhibition.
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Fu RH, Liu SP, Huang SJ, Chen HJ, Chen PR, Lin YH, Ho YC, Chang WL, Tsai CH, Shyu WC, Lin SZ. Aberrant Alternative Splicing Events in Parkinson's Disease. Cell Transplant 2013; 22:653-61. [PMID: 23127794 DOI: 10.3727/096368912x655154] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alternative splicing (AS) using a sole gene to express multiple transcripts with diverse protein coding sequences and/or RNA regulatory elements raises genomic complexities. In the nervous system, several thousand AS events play important roles in ion transportation, receptor recognition, neurotransmission, memory, and learning. Not surprisingly, AS influences human physiology, development, and disease. Many research studies have focused on aberrant AS in nervous system diseases, including Parkinson's disease (PD), the second most common progressive neurodegenerative disorder of the central nervous system. PD affects the lives of several million people globally. It is caused by protein aggregation, such as in Lewy bodies, and the loss of dopamine-containing neurons in the substantia nigra of the midbrain. To our knowledge, six genes, including PARK2, SNCAIP, LRRK2, SNCA, SRRM2, and MAPT, are involved in aberrant AS events in PD patients. In this review, we highlight the relevance of aberrant AS in PD and discuss the use of an aberrant AS profile as a potential diagnostic or prognostic marker for PD and as a possible means of applying therapy.
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Affiliation(s)
- Ru-Huei Fu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan, ROC
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
| | - Shih-Ping Liu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan, ROC
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan, ROC
| | - Shyh-Jer Huang
- Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, ROC
| | - Hung-Jen Chen
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan, ROC
| | - Pin-Ru Chen
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
| | - Ya-Hsien Lin
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
| | - Yu-Chen Ho
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
| | - Wen-Lin Chang
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
| | - Chang-Hai Tsai
- Department of Pediatrics, China Medical University Hospital, Taichung, Taiwan, ROC
- Department of Healthcare Administration, Asia University, Taichung, Taiwan, ROC
| | - Woei-Cherng Shyu
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan, ROC
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
| | - Shinn-Zong Lin
- Center for Neuropsychiatry, China Medical University Hospital, Taichung, Taiwan, ROC
- Graduate Institute of Immunology, China Medical University, Taichung, Taiwan, ROC
- Department of Healthcare Administration, Asia University, Taichung, Taiwan, ROC
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31
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Panelli D, Lorusso FP, Papa F, Panelli P, Stella A, Caputi M, Sardanelli AM, Papa S. The mechanism of alternative splicing of the X-linked NDUFB11 gene of the respiratory chain complex I, impact of rotenone treatment in neuroblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:211-8. [PMID: 23246602 DOI: 10.1016/j.bbagrm.2012.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 11/12/2012] [Accepted: 12/05/2012] [Indexed: 12/25/2022]
Abstract
A study is presented on the regulation of alternative splicing (AS) of the Ndufb11 gene of complex I of the mitochondrial respiratory chain and the impact on this process of rotenone treatment in neuroblastoma cells. In physiological conditions the Ndufb11 gene produces at high level a short transcript isoform encoding for a 153 aa protein. This subunit is essential for the assembly of a functional and stable mammalian complex I. The gene produces also, at low level, a longer transcript isoform encoding for a 163 aa protein whose role is unknown. Evidence is presented here showing that the level of the two isoforms is regulated by three DGGGD ESS elements located in exon 2 which can bind the hnRNPH1 protein. In neuronal cells rotenone treatment affects the Ndufb11 alternative splicing pathway, with the increase of the 163/153 mRNAs ratio. This effect appears to be due to the down-regulation of the hnRNPH1 protein. Since rotenone induces apoptosis in neuronal cells, the post-transcriptional regulation of the Ndufb11 gene can be involved in the programmed cell death process.
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Affiliation(s)
- Damiano Panelli
- Department of Basic Medical Sciences, University of Bari Aldo Moro, Bari, Italy.
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Perfeito R, Cunha-Oliveira T, Rego AC. Revisiting oxidative stress and mitochondrial dysfunction in the pathogenesis of Parkinson disease--resemblance to the effect of amphetamine drugs of abuse. Free Radic Biol Med 2012; 53:1791-806. [PMID: 22967820 DOI: 10.1016/j.freeradbiomed.2012.08.569] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 12/15/2022]
Abstract
Parkinson disease (PD) is a chronic and progressive neurological disease associated with a loss of dopaminergic neurons. In most cases the disease is sporadic but genetically inherited cases also exist. One of the major pathological features of PD is the presence of aggregates that localize in neuronal cytoplasm as Lewy bodies, mainly composed of α-synuclein (α-syn) and ubiquitin. The selective degeneration of dopaminergic neurons suggests that dopamine itself may contribute to the neurodegenerative process in PD. Furthermore, mitochondrial dysfunction and oxidative stress constitute key pathogenic events of this disorder. Thus, in this review we give an actual perspective to classical pathways involving these two mechanisms of neurodegeneration, including the role of dopamine in sporadic and familial PD, as well as in the case of abuse of amphetamine-type drugs. Mutations in genes related to familial PD causing autosomal dominant or recessive forms may also have crucial effects on mitochondrial morphology, function, and oxidative stress. Environmental factors, such as MPTP and rotenone, have been reported to induce selective degeneration of the nigrostriatal pathways leading to α-syn-positive inclusions, possibly by inhibiting mitochondrial complex I of the respiratory chain and subsequently increasing oxidative stress. Recently, increased risk for PD was found in amphetamine users. Amphetamine drugs have effects similar to those of other environmental factors for PD, because long-term exposure to these drugs leads to dopamine depletion. Moreover, amphetamine neurotoxicity involves α-syn aggregation, mitochondrial dysfunction, and oxidative stress. Therefore, dopamine and related oxidative stress, as well as mitochondrial dysfunction, seem to be common links between PD and amphetamine neurotoxicity.
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Affiliation(s)
- Rita Perfeito
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
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33
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Rein-Smith CM, Anderson NW, Farrell DH. Differential regulation of fibrinogen γ chain splice isoforms by interleukin-6. Thromb Res 2012; 131:89-93. [PMID: 23036532 DOI: 10.1016/j.thromres.2012.09.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 09/14/2012] [Accepted: 09/20/2012] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Fibrinogen is a major structural protein in blood clots, and is also a well-known acute phase reactant. The γ chain gene of fibrinogen has two alternative splice variants, γA and γ' chains. γ' fibrinogen constitutes about 7% of total fibrinogen. Total fibrinogen levels and γ' fibrinogen levels have been associated with cardiovascular disease, but the mechanisms regulating the production of the two isoforms are unknown. Several inflammatory cytokines are known to influence the production of total fibrinogen, but the role of cytokines in the production of γ' fibrinogen has not been examined. However, epidemiologic studies have shown an association between γ' fibrinogen levels and inflammatory markers in humans. MATERIALS AND METHODS The expression of γ' fibrinogen and total fibrinogen by HepG2 liver cells was quantitated after treatment with interleukin-1β, transforming growth factor-β, tumor necrosis factor-α, and interleukin-6. RESULTS Interleukin-1β, transforming growth factor-β, and tumor necrosis factor-α, known down-regulators of total fibrinogen synthesis, also downregulate γ' fibrinogen synthesis in HepG2 cells. However, interleukin-6 differentially up-regulates the production of total and γ' fibrinogen, leading to a 3.6-fold increase in γA mRNA, but an 8.3-fold increase in γ' mRNA. CONCLUSIONS These findings indicate that γ' fibrinogen is disproportionately up-regulated by inflammatory responses induced by interleukin-6.
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Affiliation(s)
- Chantelle M Rein-Smith
- Department of Molecular and Medical Genetics, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA
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Silva BA, Breydo L, Fink AL, Uversky VN. Agrochemicals, α-synuclein, and Parkinson's disease. Mol Neurobiol 2012; 47:598-612. [PMID: 22933040 DOI: 10.1007/s12035-012-8333-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 08/13/2012] [Indexed: 12/21/2022]
Abstract
Epidemiological, population-based case-control, and experimental studies at the molecular, cellular, and organism levels revealed that exposure to various environmental agents, including a number of structurally different agrochemicals, may contribute to the pathogenesis of Parkinson's disease (PD) and several other neurodegenerative disorders. The role of genetic predisposition in PD has also been increasingly acknowledged, driven by the identification of a number of disease-related genes [e.g., α-synuclein, parkin, DJ-1, ubiquitin C-terminal hydrolase isozyme L1 (UCH-L1), and nuclear receptor-related factor 1]. Therefore, the etiology of this multifactorial disease is likely to involve both genetic and environmental factors. Various neurotoxicants, including agrochemicals, have been shown to elevate the levels of α-synuclein expression in neurons and to promote aggregation of this protein in vivo. Many agrochemicals physically interact with α-synuclein and accelerate the fibrillation and aggregation rates of this protein in vitro. This review analyzes some of the aspects linking α-synuclein to PD, provides brief structural and functional descriptions of this important protein, and represents some data connecting exposure to agrochemicals with α-synuclein aggregation and PD pathogenesis.
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Affiliation(s)
- Blanca A Silva
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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35
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Beyer K, Ariza A. Alpha-Synuclein Posttranslational Modification and Alternative Splicing as a Trigger for Neurodegeneration. Mol Neurobiol 2012; 47:509-24. [DOI: 10.1007/s12035-012-8330-5] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 08/13/2012] [Indexed: 12/11/2022]
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Xiong N, Long X, Xiong J, Jia M, Chen C, Huang J, Ghoorah D, Kong X, Lin Z, Wang T. Mitochondrial complex I inhibitor rotenone-induced toxicity and its potential mechanisms in Parkinson's disease models. Crit Rev Toxicol 2012; 42:613-32. [PMID: 22574684 DOI: 10.3109/10408444.2012.680431] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The etiology of Parkinson's disease (PD) is attributed to both environmental and genetic factors. The development of PD reportedly involves mitochondrial impairment, oxidative stress, α-synuclein aggregation, dysfunctional protein degradation, glutamate toxicity, calcium overloading, inflammation and loss of neurotrophic factors. Based on a link between mitochondrial dysfunction and pesticide exposure, many laboratories, including ours, have recently developed parkinsonian models by utilization of rotenone, a well-known mitochondrial complex I inhibitor. Rotenone models for PD appear to mimic most clinical features of idiopathic PD and recapitulate the slow and progressive loss of dopaminergic (DA) neurons and the Lewy body formation in the nigral-striatal system. Notably, potential human parkinsonian pathogenetic and pathophysiological mechanisms have been revealed through these models. In this review, we summarized various rotenone-based models for PD and discussed the implied etiology of and treatment for PD.
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Affiliation(s)
- Nian Xiong
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei 430022, China
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Transcript expression levels of full-length alpha-synuclein and its three alternatively spliced variants in Parkinson's disease brain regions and in a transgenic mouse model of alpha-synuclein overexpression. Mol Cell Neurosci 2011; 49:230-9. [PMID: 22155155 DOI: 10.1016/j.mcn.2011.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 10/28/2011] [Accepted: 11/26/2011] [Indexed: 01/22/2023] Open
Abstract
Alternative splicing is a complex post-transcriptional process that can be regulated by cis-acting elements located within genomic non-coding regions. Recent studies have identified that polymorphic variations in non-coding regions of the α-synuclein gene (SNCA) locus are associated with an increased risk for developing Parkinson's disease (PD). The underlying mechanism(s) for this susceptibility may involve changes in α-synuclein mRNA expression and alternative splicing. As a first step towards understanding the biology of α-synuclein splice variants in PD, we characterized the levels of the full-length SNCA-140 mRNA transcript and SNCA-126, -112, and -98 alternatively spliced variants in different neuronal regions from PD patients or transgenic mice overexpressing human α-synuclein (ASO). In human post-mortem tissue, α-synuclein spliced transcripts were expressed in a region-specific manner in the cortex, substantia nigra, and cerebellum. We observed increased nigral SNCA-140 and SNCA-126 transcript levels in PD patients when compared to neurologically unaffected cases. Human α-synuclein splicing changes were also found to occur in a region-specific manner in ASO mice. Here, SNCA-126, -112, and -98 transcript levels did not increase proportionally with SNCA-140 levels, or parallel the region-specific mouse transcript ratios seen in wild-type (WT) littermates. While most transcripts were elevated in ASO mice when compared to WT mice, the most prominent increase was found in the ventral midbrain of 15-month-old ASO mice. These results demonstrate region-specific human α-synuclein transcript level abnormalities in PD patients and in a transgenic mouse model of α-synucleinopathy. This study is relevant to understanding the normal, adaptive, or pathological role(s) of α-synuclein splice variants.
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Herraiz T, Guillén H. Inhibition of the bioactivation of the neurotoxin MPTP by antioxidants, redox agents and monoamine oxidase inhibitors. Food Chem Toxicol 2011; 49:1773-81. [DOI: 10.1016/j.fct.2011.04.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/18/2011] [Accepted: 04/20/2011] [Indexed: 02/06/2023]
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Wang XJ, Zhang S, Yan ZQ, Zhao YX, Zhou HY, Wang Y, Lu GQ, Zhang JD. Impaired CD200-CD200R-mediated microglia silencing enhances midbrain dopaminergic neurodegeneration: roles of aging, superoxide, NADPH oxidase, and p38 MAPK. Free Radic Biol Med 2011; 50:1094-106. [PMID: 21295135 DOI: 10.1016/j.freeradbiomed.2011.01.032] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 01/24/2011] [Accepted: 01/25/2011] [Indexed: 11/24/2022]
Abstract
CD200-CD200R signaling holds microglia in a quiescent state. Parkinson disease (PD) neurodegeneration may be associated with impairment of CD200-CD200R-mediated microglia silencing in the substantia nigra (SN). In this study, an anti-CD200R blocking antibody (ACDR) selectively and significantly enhanced the susceptibility of dopaminergic neurons to neurotoxicity induced by rotenone (Rot) and iron (Ir) in mesencephalic neuron/glia cultures. Microglia were shown to mediate dopaminergic neurotoxicity induced by ACDR/Rot (combination of ACDR and Rot) and ACDR/Ir (combination of ACDR and Ir). ACDR significantly enhanced the microglial activation induced by Rot and Ir in neuron/glia cultures. NADPH oxidase-mediated superoxide generation was a key contributor to dopaminergic neurotoxicity induced by ACDR/Rot and ACDR/Ir. p38 MAPK contributed to NADPH oxidase activation induced by ACDR/Rot and ACDR/Ir. Interestingly, there were a decrease in CD200 expression (mRNA and protein) and an enhancement of microglial response (MHCII mRNA and ICAM-1 protein) in the rat SN with aging. ICAM-1 expression was significantly inversely correlated with CD200 expression. These results strongly indicate the participation of SN CD200-CD200R dysfunction in the etiopathogenesis of PD and provide a new insight into the molecular mechanisms underlying the involvement of aging in PD and help to elucidate the mechanisms of the combined involvement of immune/inflammatory factors, environmental substances, and aging in PD.
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Affiliation(s)
- Xi-Jin Wang
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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Venda LL, Cragg SJ, Buchman VL, Wade-Martins R. α-Synuclein and dopamine at the crossroads of Parkinson's disease. Trends Neurosci 2010; 33:559-68. [PMID: 20961626 PMCID: PMC3631137 DOI: 10.1016/j.tins.2010.09.004] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 09/14/2010] [Accepted: 09/14/2010] [Indexed: 12/19/2022]
Abstract
α-Synuclein is central to the Lewy body neuropathology of Parkinson's disease (PD), a devastating neurodegenerative disorder characterized by numerous motor and non-motor manifestations. The cardinal motor symptoms are linked to death of dopaminergic neurons in the nigrostriatal pathway. Here we ask why these neurons are preferentially susceptible to neurodegeneration in PD and how α-synuclein is involved. To address these questions we bring together recent findings from genome-wide association studies, which reveal the involvement of α-synuclein gene variants in sporadic PD, with recent studies highlighting important roles for α-synuclein in synaptic transmission and dopaminergic neuron physiology. These latest advances add to our understanding of PD etiology and provide a central link between the genetic findings and neurodegeneration observed in sporadic PD.
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Affiliation(s)
- Lara Lourenço Venda
- Department of Physiology, Anatomy and Genetics; Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
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