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Droppelmann CA, Campos-Melo D, Noches V, McLellan C, Szabla R, Lyons TA, Amzil H, Withers B, Kaplanis B, Sonkar KS, Simon A, Buratti E, Junop M, Kramer JM, Strong MJ. Mitigation of TDP-43 toxic phenotype by an RGNEF fragment in amyotrophic lateral sclerosis models. Brain 2024; 147:2053-2068. [PMID: 38739752 PMCID: PMC11146434 DOI: 10.1093/brain/awae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/24/2024] [Accepted: 02/08/2024] [Indexed: 05/16/2024] Open
Abstract
Aggregation of the RNA-binding protein TAR DNA binding protein (TDP-43) is a hallmark of TDP-proteinopathies including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). As TDP-43 aggregation and dysregulation are causative of neuronal death, there is a special interest in targeting this protein as a therapeutic approach. Previously, we found that TDP-43 extensively co-aggregated with the dual function protein GEF (guanine exchange factor) and RNA-binding protein rho guanine nucleotide exchange factor (RGNEF) in ALS patients. Here, we show that an N-terminal fragment of RGNEF (NF242) interacts directly with the RNA recognition motifs of TDP-43 competing with RNA and that the IPT/TIG domain of NF242 is essential for this interaction. Genetic expression of NF242 in a fruit fly ALS model overexpressing TDP-43 suppressed the neuropathological phenotype increasing lifespan, abolishing motor defects and preventing neurodegeneration. Intracerebroventricular injections of AAV9/NF242 in a severe TDP-43 murine model (rNLS8) improved lifespan and motor phenotype, and decreased neuroinflammation markers. Our results demonstrate an innovative way to target TDP-43 proteinopathies using a protein fragment with a strong affinity for TDP-43 aggregates and a mechanism that includes competition with RNA sequestration, suggesting a promising therapeutic strategy for TDP-43 proteinopathies such as ALS and FTD.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Veronica Noches
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Crystal McLellan
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Robert Szabla
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Taylor A Lyons
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Hind Amzil
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Benjamin Withers
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Brianna Kaplanis
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Kirti S Sonkar
- International Centre for Genetic Engineering and Biotechnology (ICGEB), AREA Science Park, 34149 Trieste, Italy
| | - Anne Simon
- Department of Biology, Faculty of Science, Western University, London, Ontario N6A 5B7, Canada
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), AREA Science Park, 34149 Trieste, Italy
| | - Murray Junop
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
| | - Jamie M Kramer
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
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Nelson PT, Fardo DW, Wu X, Aung KZ, Cykowski MD, Katsumata Y. Limbic-predominant age-related TDP-43 encephalopathy (LATE-NC): Co-pathologies and genetic risk factors provide clues about pathogenesis. J Neuropathol Exp Neurol 2024; 83:396-415. [PMID: 38613823 PMCID: PMC11110076 DOI: 10.1093/jnen/nlae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2024] Open
Abstract
Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is detectable at autopsy in more than one-third of people beyond age 85 years and is robustly associated with dementia independent of other pathologies. Although LATE-NC has a large impact on public health, there remain uncertainties about the underlying biologic mechanisms. Here, we review the literature from human studies that may shed light on pathogenetic mechanisms. It is increasingly clear that certain combinations of pathologic changes tend to coexist in aging brains. Although "pure" LATE-NC is not rare, LATE-NC often coexists in the same brains with Alzheimer disease neuropathologic change, brain arteriolosclerosis, hippocampal sclerosis of aging, and/or age-related tau astrogliopathy (ARTAG). The patterns of pathologic comorbidities provide circumstantial evidence of mechanistic interactions ("synergies") between the pathologies, and also suggest common upstream influences. As to primary mediators of vulnerability to neuropathologic changes, genetics may play key roles. Genes associated with LATE-NC include TMEM106B, GRN, APOE, SORL1, ABCC9, and others. Although the anatomic distribution of TDP-43 pathology defines the condition, important cofactors for LATE-NC may include Tau pathology, endolysosomal pathways, and blood-brain barrier dysfunction. A review of the human phenomenology offers insights into disease-driving mechanisms, and may provide clues for diagnostic and therapeutic targets.
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Affiliation(s)
- Peter T Nelson
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, Kentucky, USA
- Department of Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
| | - David W Fardo
- Department of Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
- Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
| | - Xian Wu
- Department of Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
- Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
| | - Khine Zin Aung
- Department of Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
- Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
| | - Matthew D Cykowski
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Yuriko Katsumata
- Department of Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
- Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
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Katsumata Y, Fardo DW, Shade LMP, Wu X, Karanth SD, Hohman TJ, Schneider JA, Bennett DA, Farfel JM, Gauthreaux K, Mock C, Kukull WA, Abner EL, Nelson PT. Genetic associations with dementia-related proteinopathy: Application of item response theory. Alzheimers Dement 2024; 20:2906-2921. [PMID: 38460116 PMCID: PMC11032554 DOI: 10.1002/alz.13741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 03/11/2024]
Abstract
INTRODUCTION Although dementia-related proteinopathy has a strong negative impact on public health, and is highly heritable, understanding of the related genetic architecture is incomplete. METHODS We applied multidimensional generalized partial credit modeling (GPCM) to test genetic associations with dementia-related proteinopathies. Data were analyzed to identify candidate single nucleotide variants for the following proteinopathies: Aβ, tau, α-synuclein, and TDP-43. RESULTS Final included data comprised 966 participants with neuropathologic and WGS data. Three continuous latent outcomes were constructed, corresponding to TDP-43-, Aβ/Tau-, and α-synuclein-related neuropathology endophenotype scores. This approach helped validate known genotype/phenotype associations: for example, TMEM106B and GRN were risk alleles for TDP-43 pathology; and GBA for α-synuclein/Lewy bodies. Novel suggestive proteinopathy-linked alleles were also discovered, including several (SDHAF1, TMEM68, and ARHGEF28) with colocalization analyses and/or high degrees of biologic credibility. DISCUSSION A novel methodology using GPCM enabled insights into gene candidates for driving misfolded proteinopathies. HIGHLIGHTS Latent factor scores for proteinopathies were estimated using a generalized partial credit model. The three latent continuous scores corresponded well with proteinopathy severity. Novel genes associated with proteinopathies were identified. Several genes had high degrees of biologic credibility for dementia risk factors.
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Affiliation(s)
- Yuriko Katsumata
- Department of BiostatisticsUniversity of KentuckyLexingtonKentuckyUSA
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
| | - David W. Fardo
- Department of BiostatisticsUniversity of KentuckyLexingtonKentuckyUSA
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
| | | | - Xian Wu
- Department of BiostatisticsUniversity of KentuckyLexingtonKentuckyUSA
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
| | - Shama D. Karanth
- Department of SurgeryCollege of MedicineUniversity of FloridaGainesvilleFloridaUSA
- UF Health Cancer CenterUniversity of FloridaGainesvilleFloridaUSA
| | - Timothy J. Hohman
- Vanderbilt Memory and Alzheimer's CenterVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Julie A. Schneider
- Department of Neurological SciencesRush University Medical CenterChicagoIllinoisUSA
- Department of PathologyRush University Medical CenterChicagoIllinoisUSA
- Rush Alzheimer's Disease CenterRush University Medical CenterChicagoIllinoisUSA
| | - David A. Bennett
- Department of Neurological SciencesRush University Medical CenterChicagoIllinoisUSA
- Department of PathologyRush University Medical CenterChicagoIllinoisUSA
- Rush Alzheimer's Disease CenterRush University Medical CenterChicagoIllinoisUSA
| | - Jose M. Farfel
- Department of PathologyRush University Medical CenterChicagoIllinoisUSA
- Rush Alzheimer's Disease CenterRush University Medical CenterChicagoIllinoisUSA
| | - Kathryn Gauthreaux
- National Alzheimer's Coordinating CenterDepartment of EpidemiologyUniversity of WashingtonSeattleWashingtonUSA
| | - Charles Mock
- National Alzheimer's Coordinating CenterDepartment of EpidemiologyUniversity of WashingtonSeattleWashingtonUSA
| | - Walter A. Kukull
- National Alzheimer's Coordinating CenterDepartment of EpidemiologyUniversity of WashingtonSeattleWashingtonUSA
| | - Erin L. Abner
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
- Department of Epidemiology and Environmental HealthUniversity of KentuckyLexingtonKentuckyUSA
| | - Peter T. Nelson
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
- Department of PathologyDivision of NeuropathologyUniversity of KentuckyLexingtonKentuckyUSA
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De Marchi F, Franjkic T, Schito P, Russo T, Nimac J, Chami AA, Mele A, Vidatic L, Kriz J, Julien JP, Apic G, Russell RB, Rogelj B, Cannon JR, Baralle M, Agosta F, Hecimovic S, Mazzini L, Buratti E, Munitic I. Emerging Trends in the Field of Inflammation and Proteinopathy in ALS/FTD Spectrum Disorder. Biomedicines 2023; 11:1599. [PMID: 37371694 PMCID: PMC10295684 DOI: 10.3390/biomedicines11061599] [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: 04/28/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Proteinopathy and neuroinflammation are two main hallmarks of neurodegenerative diseases. They also represent rare common events in an exceptionally broad landscape of genetic, environmental, neuropathologic, and clinical heterogeneity present in patients. Here, we aim to recount the emerging trends in amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) spectrum disorder. Our review will predominantly focus on neuroinflammation and systemic immune imbalance in ALS and FTD, which have recently been highlighted as novel therapeutic targets. A common mechanism of most ALS and ~50% of FTD patients is dysregulation of TAR DNA-binding protein 43 (TDP-43), an RNA/DNA-binding protein, which becomes depleted from the nucleus and forms cytoplasmic aggregates in neurons and glia. This, in turn, via both gain and loss of function events, alters a variety of TDP-43-mediated cellular events. Experimental attempts to target TDP-43 aggregates or manipulate crosstalk in the context of inflammation will be discussed. Targeting inflammation, and the immune system in general, is of particular interest because of the high plasticity of immune cells compared to neurons.
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Affiliation(s)
- Fabiola De Marchi
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Toni Franjkic
- Laboratory for Molecular Immunology, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia;
- Metisox, Cambridge CB24 9NL, UK;
| | - Paride Schito
- Department of Neurology & Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.S.); (T.R.)
| | - Tommaso Russo
- Department of Neurology & Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.S.); (T.R.)
| | - Jerneja Nimac
- Department of Biotechnology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; (J.N.); (B.R.)
- Graduate School of Biomedicine, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Anna A. Chami
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | - Angelica Mele
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Lea Vidatic
- Laboratory for Neurodegenerative Disease Research, Division of Molecular Medicine, Ruder Boskovic Institute, 10000 Zagreb, Croatia; (L.V.); (S.H.)
| | - Jasna Kriz
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | - Jean-Pierre Julien
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | | | | | - Boris Rogelj
- Department of Biotechnology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; (J.N.); (B.R.)
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Jason R. Cannon
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA;
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | | | - Federica Agosta
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy;
| | - Silva Hecimovic
- Laboratory for Neurodegenerative Disease Research, Division of Molecular Medicine, Ruder Boskovic Institute, 10000 Zagreb, Croatia; (L.V.); (S.H.)
| | - Letizia Mazzini
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Ivana Munitic
- Laboratory for Molecular Immunology, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia;
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Yuan A, Nixon RA. Posttranscriptional regulation of neurofilament proteins and tau in health and disease. Brain Res Bull 2023; 192:115-127. [PMID: 36441047 PMCID: PMC9907725 DOI: 10.1016/j.brainresbull.2022.10.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/20/2022] [Accepted: 10/26/2022] [Indexed: 01/16/2023]
Abstract
Neurofilament and tau proteins are neuron-specific cytoskeletal proteins that are enriched in axons, regulated by many of the same protein kinases, interact physically, and are the principal constituents of neurofibrillary lesions in major adult-onset dementias. Both proteins share functions related to the modulation of stability and functions of the microtubule network in axons, axonal transport and scaffolding of organelles, long-term synaptic potentiation, and learning and memory. Expression of these proteins is regulated not only at the transcriptional level but also through posttranscriptional control of pre-mRNA splicing, mRNA stability, transport, localization, local translation and degradation. Current evidence suggests that posttranscriptional determinants of their levels are usually regulated by RNA-binding proteins and microRNAs primarily through 3'-untranslated regions of neurofilament and tau mRNAs. Dysregulations of neurofilament and tau expression caused by mutations or pathologies of RNA-binding proteins such as TDP43, FUS and microRNAs are increasingly recognized in association with varied neurological disorders. In this review, we summarize the current understanding of posttranscriptional control of neurofilament and tau by examining the posttranscriptional regulation of neurofilament and tau by RNA-binding proteins and microRNAs implicated in health and diseases.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA,Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA,Department of Cell Biology, New York University Langone Health, New York, NY 10016, USA,NYU Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA,Correspondence to: Center for Dementia Research, Nathan Kline Institute, New York University Langone Health, New York, NY 10016, USA, (A. Yuan), (R.A. Nixon)
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6
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Utility of RGNEF in the Prediction of Clinical Prognosis in Patients with Rectal Cancer Receiving Preoperative Concurrent Chemoradiotherapy. Life (Basel) 2021; 12:life12010018. [PMID: 35054411 PMCID: PMC8778573 DOI: 10.3390/life12010018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/08/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022] Open
Abstract
Rectal cancer is a heterogeneous malignancy with different clinical responses to preoperative concurrent chemoradiotherapy (CCRT). To discover the significant genes associated with CCRT response, we performed data mining of a transcriptomic dataset (GSE35452), including 46 rectal cancer patients who received preoperative CCRT and underwent standardized curative resection. We identified ARHGEF28 as the most significantly upregulated gene correlated with resistance to CCRT among the genes related to Rho guanyl-nucleotide exchange factor activity (GO:0005085). We enrolled 172 patients with rectal cancer receiving CCRT with radical surgery. The expression of ARHGEF28 encoded protein, Rho guanine nucleotide exchange factor (RGNEF), was assessed using immunohistochemistry. The results showed that upregulated RGNEF immunoexpression was considerably correlated with poor response to CCRT (p = 0.018), pre-CCRT positive nodal status (p = 0.004), and vascular invasion (p < 0.001). Furthermore, high RGNEF expression was significantly associated with worse local recurrence-free survival (p < 0.0001), metastasis-free survival (MeFS) (p = 0.0029), and disease-specific survival (DSS) (p < 0.0001). The multivariate analysis demonstrated that RGNEF immunoexpression status was an independent predictor of DSS (p < 0.001) and MeFS (p < 0.001). Using Gene Ontology enrichment analysis, we discovered that ARHGEF28 overexpression might be linked to Wnt/β-catenin signaling in rectal cancer progression. In conclusion, high RGNEF expression was related to unfavorable pathological characteristics and independently predicted worse clinical prognosis in patients with rectal cancer undergoing CCRT, suggesting its role in risk stratification and clinical decision making.
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7
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Volkening K, Farhan SMK, Kao J, Leystra-Lantz C, Ang LC, McIntyre A, Wang J, Hegele RA, Strong MJ. Evidence of synergism among three genetic variants in a patient with LMNA-related lipodystrophy and amyotrophic lateral sclerosis leading to a remarkable nuclear phenotype. Mol Cell Biochem 2021; 476:2633-2650. [PMID: 33661429 PMCID: PMC8192393 DOI: 10.1007/s11010-021-04103-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 02/06/2021] [Indexed: 11/25/2022]
Abstract
Neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), can be clinically heterogeneous which may be explained by the co-inheritance of multiple genetic variants that modify the clinical course. In this study we examine variants in three genes in a family with one individual presenting with ALS and lipodystrophy. Sequencing revealed a p.Gly602Ser variant in LMNA, and two additional variants, one each in SETX (g.intron10-13delCTT) and FUS (p.Gly167_Gly168del). These latter genes have been linked to ALS. All family members were genotyped and each variant, and each combination of variants detected, were functionally evaluated in vitro regarding effects on cell survival, expression patterns and cellular phenotype. Muscle biopsy retrieved from the individual with ALS showed leakage of chromatin from the nucleus, a phenotype that was recapitulated in vitro with expression of all three variants simultaneously. Individually expressed variants gave cellular phenotypes there were unremarkable. Interestingly the FUS variant appears to be protective against the effects of the SETX and the LMNA variants on cell viability and may indicate loss of interaction of FUS with SETX and/or R-loops. We conclude that these findings support genetic modifications as an explanation of the clinical heterogeneity observed in human disease.
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Affiliation(s)
- Kathryn Volkening
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Sali M K Farhan
- Analytic and Translational Genetics Unit, Center for Genomic Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Jessica Kao
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Cheryl Leystra-Lantz
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Lee Cyn Ang
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre-University Hospital, London, ON, Canada
| | - Adam McIntyre
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Jian Wang
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Robert A Hegele
- Department of Pathology and Laboratory Medicine, London Health Sciences Centre-University Hospital, London, ON, Canada
- Blackburn Cardiovascular Genetics Lab, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
- Department of Biochemistry, Western University, London, ON, Canada
| | - Michael J Strong
- Molecular Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
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8
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Strong MJ, Donison NS, Volkening K. Alterations in Tau Metabolism in ALS and ALS-FTSD. Front Neurol 2020; 11:598907. [PMID: 33329356 PMCID: PMC7719764 DOI: 10.3389/fneur.2020.598907] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022] Open
Abstract
There is increasing acceptance that amyotrophic lateral sclerosis (ALS), classically considered a neurodegenerative disease affecting almost exclusively motor neurons, is syndromic with both clinical and biological heterogeneity. This is most evident in its association with a broad range of neuropsychological, behavioral, speech and language deficits [collectively termed ALS frontotemporal spectrum disorder (ALS-FTSD)]. Although the most consistent pathology of ALS and ALS-FTSD is a disturbance in TAR DNA binding protein 43 kDa (TDP-43) metabolism, alterations in microtubule-associated tau protein (tau) metabolism can also be observed in ALS-FTSD, most prominently as pathological phosphorylation at Thr175 (pThr175tau). pThr175 has been shown to promote exposure of the phosphatase activating domain (PAD) in the tau N-terminus with the consequent activation of GSK3β mediated phosphorylation at Thr231 (pThr231tau) leading to pathological oligomer formation. This pathological cascade of tau phosphorylation has been observed in chronic traumatic encephalopathy with ALS (CTE-ALS) and in both in vivo and in vitro experimental paradigms, suggesting that it is of critical relevance to the pathobiology of ALS-FTSD. It is also evident that the co-existence of alterations in the metabolism of TDP-43 and tau acts synergistically in a rodent model to exacerbate the pathology of either.
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Affiliation(s)
- Michael J Strong
- Molecular Medicine, Schulich School of Medicine and Dentistry, Robarts Research Institute, Western University, London, ON, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Neil S Donison
- Molecular Medicine, Schulich School of Medicine and Dentistry, Robarts Research Institute, Western University, London, ON, Canada.,Neuroscience Graduate Program, Western University, London, ON, Canada
| | - Kathryn Volkening
- Molecular Medicine, Schulich School of Medicine and Dentistry, Robarts Research Institute, Western University, London, ON, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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9
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Di Gregorio SE, Volkening K, Strong MJ, Duennwald ML. Inclusion Formation and Toxicity of the ALS Protein RGNEF and Its Association with the Microtubule Network. Int J Mol Sci 2020; 21:ijms21165597. [PMID: 32764283 PMCID: PMC7460592 DOI: 10.3390/ijms21165597] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/15/2020] [Accepted: 07/31/2020] [Indexed: 12/11/2022] Open
Abstract
The Rho guanine nucleotide exchange factor (RGNEF) protein encoded by the ARHGEF28 gene has been implicated in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Biochemical and pathological studies have shown that RGNEF is a component of the hallmark neuronal cytoplasmic inclusions in ALS-affected neurons. Additionally, a heterozygous mutation in ARHGEF28 has been identified in a number of familial ALS (fALS) cases that may give rise to one of two truncated variants of the protein. Little is known about the normal biological function of RGNEF or how it contributes to ALS pathogenesis. To further explore RGNEF biology we have established and characterized a yeast model and characterized RGNEF expression in several mammalian cell lines. We demonstrate that RGNEF is toxic when overexpressed and forms inclusions. We also found that the fALS-associated mutation in ARGHEF28 gives rise to an inclusion-forming and toxic protein. Additionally, through unbiased screening using the split-ubiquitin system, we have identified RGNEF-interacting proteins, including two ALS-associated proteins. Functional characterization of other RGNEF interactors identified in our screen suggest that RGNEF functions as a microtubule regulator. Our findings indicate that RGNEF misfolding and toxicity may cause impairment of the microtubule network and contribute to ALS pathogenesis.
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Affiliation(s)
- Sonja E. Di Gregorio
- Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON N6A 5C1, Canada;
| | - Kathryn Volkening
- Clinical Neurological Sciences, University of Western Ontario, London, ON N6A 5C1, Canada; (K.V.); (M.J.S.)
| | - Michael J. Strong
- Clinical Neurological Sciences, University of Western Ontario, London, ON N6A 5C1, Canada; (K.V.); (M.J.S.)
| | - Martin L. Duennwald
- Department of Pathology and Laboratory Medicine, University of Western Ontario, London, ON N6A 5C1, Canada;
- Correspondence:
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10
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Zhao M, Kao CS, Arndt C, Tran DD, Cho WI, Maksimovic K, Chen XXL, Khan M, Zhu H, Qiao J, Peng K, Hong J, Xu J, Kim D, Kim JR, Lee J, van Bruggen R, Yoon WH, Park J. Knockdown of genes involved in axonal transport enhances the toxicity of human neuromuscular disease-linked MATR3 mutations in Drosophila. FEBS Lett 2020; 594:2800-2818. [PMID: 32515490 DOI: 10.1002/1873-3468.13858] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022]
Abstract
Mutations in the nuclear matrix protein Matrin 3 (MATR3) have been identified in amyotrophic lateral sclerosis and myopathy. To investigate the mechanisms underlying MATR3 mutations in neuromuscular diseases and efficiently screen for modifiers of MATR3 toxicity, we generated transgenic MATR3 flies. Our findings indicate that expression of wild-type or mutant MATR3 in motor neurons reduces climbing ability and lifespan of flies, while their expression in indirect flight muscles (IFM) results in abnormal wing positioning and muscle degeneration. In both motor neurons and IFM, mutant MATR3 expression results in more severe phenotypes than wild-type MATR3, demonstrating that the disease-linked mutations confer pathogenicity. We conducted a targeted candidate screen for modifiers of the MATR3 abnormal wing phenotype and identified multiple enhancers involved in axonal transport. Knockdown of these genes enhanced protein levels and insolubility of mutant MATR3. These results suggest that accumulation of mutant MATR3 contributes to toxicity and implicate axonal transport dysfunction in disease pathogenesis.
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Affiliation(s)
- Melody Zhao
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Ching Serena Kao
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Claudia Arndt
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - David Duc Tran
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Woo In Cho
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Katarina Maksimovic
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Xiao Xiao Lily Chen
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Mashiat Khan
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Hongxian Zhu
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Julia Qiao
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Kailong Peng
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jingyao Hong
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jialu Xu
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Deanna Kim
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jihye Rachel Kim
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jooyun Lee
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Rebekah van Bruggen
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Wan Hee Yoon
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Jeehye Park
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
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11
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Droppelmann CA, Campos-Melo D, Moszczynski AJ, Amzil H, Strong MJ. TDP-43 aggregation inside micronuclei reveals a potential mechanism for protein inclusion formation in ALS. Sci Rep 2019; 9:19928. [PMID: 31882736 PMCID: PMC6934605 DOI: 10.1038/s41598-019-56483-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 12/12/2019] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disease with no known etiology. The formation of pathological protein inclusions, including RNA-binding proteins such as TDP-43 and rho guanine nucleotide exchange factor (RGNEF) are a hallmark of ALS. Despite intensive research, the mechanisms behind protein aggregate formation in ALS remains unclear. We have investigated the role of metabolic stress in protein aggregate formation analyzing how it is relevant to the co-aggregation observed between RGNEF and TDP-43 in motor neurons of ALS patients. Metabolic stress was able to induce formation of micronuclei, small nuclear fragments, in cultured cells. Notably, we observed the formation TDP-43 protein inclusions within micronuclei that co-aggregate with RGNEF and can be released to the cytoplasm. We observed that the leucine-rich domain of RGNEF is critical for its interaction with TDP-43 and localization in micronuclei. Finally, we described that micronuclei-like structures can be found in brain and spinal cord of ALS patients. This work is the first description of protein inclusion formation within micronuclei which also is linked with a neurodegenerative disease. The formation of TDP-43 inclusions within micronuclei induced by metabolic stress is a novel mechanism of protein aggregate formation which may have broad relevance for ALS and other neurodegenerative diseases.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
| | - Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Alexander J Moszczynski
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Hind Amzil
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada. .,Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
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12
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Song Y, Lin F, Ye CH, Huang H, Li X, Yao X, Xu Y, Wang C. Rare, low-frequency and common coding variants of ARHGEF28 gene and their association with sporadic amyotrophic lateral sclerosis. Neurobiol Aging 2019; 87:138.e1-138.e6. [PMID: 31060816 DOI: 10.1016/j.neurobiolaging.2019.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 01/14/2019] [Accepted: 02/27/2019] [Indexed: 02/05/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Over 90% of cases are sporadic (sALS) and 5%-10% are familial (fALS). So far, more than 20 genes/loci have been linked to ALS. C9orf72, SOD1, TARDBP, and FUS are noted as the most common ALS genes; however, mutations of these genes explain <10% of sALS cases. Recently, Rho guanine nucleotide exchange factor, encoded by ARHGEF28, has been linked to the ALS pathogenesis, possibly by binding low-molecular-weight neurofilament mRNA and affects its stability. However, a systemic screening of ARHGEF28 mutations in ALS is lacking. In this study, we sequenced the entire coding sequence of ARHGEF28 in a Chinese cohort of 399 sporadic ALS and 327 elderly controls. A total of 73 coding variants were identified, including 26 synonymous and 47 nonsynonymous. Among the nonsynonymous variants, 33 were rare (minor allele frequency [MAF]<0.01), in which 18 were only identified in cases and 12 were only in controls. Three loss-of-function mutations were identified, including 2 truncations (p.Arg231Ter and p.Ser561Ter) and a frameshift deletion (p.Lys1070fs) in 2 cases and 1 control subject. The frequency of total and case-only rare variants was 7.5% (30/399) and 5.0% (20/399), respectively, in the patients. SKAT-O test suggested that the novel coding variants were marginally enriched in the cases (p = 0.049). Single-variant analysis suggested that the p.Asn1046Ser variant had a higher frequency in cases (8/399, 0.02) than in controls (1/327, 0.003) (OR: 6.67, 95% CI: 0.83-53.61; p = 0.046). By contrast, none of the low-frequency (MAF: 0.01-0.05) or common (MAF > 0.05) variants was associated with ALS (p > 0.05). Among all patients, 9 (2.3%) carried rare variants predicted to be deleterious, and the age at onset of these carriers (45.6 ± 10.9 years) was marginally younger than noncarriers (51.9 ± 10.7 years) (p = 0.11). Our results supported a possible genetic contribution of rare but not low-frequency and common coding variants to ALS. These data may have implications in the mechanisms and genetic counseling of the disease.
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Affiliation(s)
- Yang Song
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Feng Lin
- Department of Neurology, Sanming First Hospital Affiliated to Fujian Medical University, Sanming, Fujian China
| | - Cheng-Hui Ye
- Department of Neurology, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Huaping Huang
- Department of Neurology, The Union Hospital Affiliated to Fujian Medical University, China
| | - Xuying Li
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Xiaoli Yao
- Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
| | - Yanming Xu
- Department of Neurology, West China Hospital of Sichuan University, Chengdu, China.
| | - Chaodong Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China; National Clinical Research Center for Geriatric Diseases, Beijing, China.
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13
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MiR-105 and miR-9 regulate the mRNA stability of neuronal intermediate filaments. Implications for the pathogenesis of amyotrophic lateral sclerosis (ALS). Brain Res 2019; 1706:93-100. [DOI: 10.1016/j.brainres.2018.10.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/19/2018] [Accepted: 10/28/2018] [Indexed: 12/19/2022]
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14
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Tavolieri MV, Droppelmann CA, Campos-Melo D, Volkening K, Strong MJ. A novel overlapping NLS/NES region within the PH domain of Rho Guanine Nucleotide Exchange Factor (RGNEF) regulates its nuclear-cytoplasmic localization. Eur J Cell Biol 2019; 98:27-35. [PMID: 30482479 DOI: 10.1016/j.ejcb.2018.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/08/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022] Open
Abstract
Rho Guanine Nucleotide Exchange Factor (RGNEF) is a 190 kDa protein implicated in both amyotrophic lateral sclerosis (ALS) and cancer. Under normal physiological conditions, RGNEF is predominantly cytoplasmic with moderate levels of nuclear localization. We have identified a 23-amino acid region containing a bipartite nuclear localization signal (NLS) within the Pleckstrin Homology (PH) domain of RGNEF, which when deleted or mutated abolishes the nuclear localization of this protein. Fusion proteins containing only the PH domain demonstrated that this region by itself is able to translocate a 160 kDa protein to the nucleus. Interestingly, we also detected a nuclear export signal (NES) within the linker region of this bipartite NLS which is able to export from the nucleus a fusion protein containing two NLSs. Experiments using Leptomycin-B -an inhibitor of nuclear export- confirmed that this region promotes nuclear export in an exportin-1 dependent manner. This study is the first report demonstrating either of these signals embedded within a PH domain. Notably, this is also the first description of a functional overlapped NLS/NES signal.
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Affiliation(s)
- Michael V Tavolieri
- Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.
| | - Cristian A Droppelmann
- Molecular Medicine Group, Robarts Research Institute, Western University, London, Ontario, Canada.
| | - Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Western University, London, Ontario, Canada.
| | - Kathryn Volkening
- Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada; Molecular Medicine Group, Robarts Research Institute, Western University, London, Ontario, Canada.
| | - Michael J Strong
- Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada; Molecular Medicine Group, Robarts Research Institute, Western University, London, Ontario, Canada.
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15
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Campos-Melo D, Hawley ZCE, Strong MJ. Dysregulation of human NEFM and NEFH mRNA stability by ALS-linked miRNAs. Mol Brain 2018; 11:43. [PMID: 30029677 PMCID: PMC6054723 DOI: 10.1186/s13041-018-0386-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/03/2018] [Indexed: 12/12/2022] Open
Abstract
Neurofilaments (NFs) are the most abundant cytoskeletal component of vertebrate myelinated axons. NFs function by determining axonal caliber, promoting axonal growth and forming a 3-dimensional lattice that supports the organization of cytoplasmic organelles. The stoichiometry of NF protein subunits (NFL, NFM and NFH) has to be tightly controlled to avoid the formation of NF neuronal cytoplasmic inclusions (NCIs), axonal degeneration and neuronal death, all pathological hallmarks of amyotrophic lateral sclerosis (ALS). The post-transcriptional control of NF transcripts is critical for regulating normal levels of NF proteins. Previously, we showed that miRNAs that are dysregulated in ALS spinal cord regulate the levels of NEFL mRNA. In order to complete the understanding of altered NF expression in ALS, in this study we have investigated the regulation of NEFM and NEFH mRNA levels by miRNAs. We observed that a small group of ALS-linked miRNAs that are expressed in human spinal motor neurons directly regulate NEFM and NEFH transcript levels in a manner that is associated with an increase in NFM and NFH protein levels in ALS spinal cord homogenates. In concert with previous observations demonstrating the suppression of NEFL mRNA steady state levels in ALS, these observations provide support for the hypothesis that the dysregulation of miRNAs in spinal motor neurons in ALS fundamentally alters the stoichiometry of NF expression, leading to the formation of pathological NCIs.
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Affiliation(s)
- Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Zachary C E Hawley
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,Department of Pathology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,University Hospital, LHSC, Rm C7-120, 339, Windermere Road, London, ON, N6A 5A5, Canada.
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16
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Volkening K, Keller BA, Leystra-Lantz C, Strong MJ. RNA and Protein Interactors with TDP-43 in Human Spinal-Cord Lysates in Amyotrophic Lateral Sclerosis. J Proteome Res 2018. [DOI: 10.1021/acs.jproteome.8b00126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Novel miR-b2122 regulates several ALS-related RNA-binding proteins. Mol Brain 2017; 10:46. [PMID: 28969660 PMCID: PMC5625648 DOI: 10.1186/s13041-017-0326-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/14/2017] [Indexed: 02/08/2023] Open
Abstract
Common pathological features of amyotrophic lateral sclerosis (ALS) include cytoplasmic aggregation of several RNA-binding proteins. Out of these RNA-binding proteins, TDP-43, FUS/TLS and RGNEF have been shown to co-aggregate with one another within motor neurons of sporadic ALS (sALS) patients, suggesting that there may be a common regulatory network disrupted. MiRNAs have been a recent focus in ALS research as they have been identified to be globally down-regulated in the spinal cord of ALS patients. The objective of this study was to identify if there are miRNA(s) dysregulated in sALS that are responsible for regulating the TDP-43, FUS/TLS and RGNEF network. In this study, we identify miR-194 and miR-b2122 to be significantly down-regulated in sALS patients, and were predicted to regulate TARDBP, FUS/TLS and RGNEF expression. Reporter gene assays and RT-qPCR revealed that miR-b2122 down-regulates the reporter gene through direct interactions with either the TARDBP, FUS/TLS, or RGNEF 3’UTR, while miR-194 down-regulates firefly expression when it contained either the TARDBP or FUS/TLS 3’UTR. Further, we showed that miR-b2122 regulates endogenous expression of all three of these genes in a neuronal-derived cell line. Also, an ALS-associated mutation in the FUS/TLS 3’UTR ablates the ability of miR-b2122 to regulate reporter gene linked to FUS/TLS 3’UTR, and sALS samples which showed a down-regulation in miR-b2122 also showed an increase in FUS/TLS protein expression. Overall, we have identified a novel miRNA that is down-regulated in sALS that appears to be a central regulator of disease-related RNA-binding proteins, and thus its dysregulation likely contributes to TDP-43, FUS/TLS and RGNEF pathogenesis in sALS.
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18
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Rho guanine nucleotide exchange factor (RGNEF) is a prosurvival factor under stress conditions. Mol Cell Neurosci 2017; 82:88-95. [PMID: 28495450 DOI: 10.1016/j.mcn.2017.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 04/06/2017] [Accepted: 05/05/2017] [Indexed: 12/13/2022] Open
Abstract
Rho guanine nucleotide exchange factor (RGNEF) is a 190kDa RNA binding protein (RBP) that also contains a Dbl/PH domain capable of RhoA activation. Consistent with a key role in the pathogenesis of amyotrophic lateral sclerosis (ALS), RGNEF forms pathological neuronal cytoplasmic inclusions in degenerating spinal motor neurons. To further understand the role of RGNEF in the stress response, we first observed that the expression of RGNEF is upregulated in murine spinal motor neurons following distal sciatic nerve injury. Secondly, in response to in vitro cellular stress (500μM sodium arsenite for 1h; or 400mM sorbitol 1 hour exposure; as an oxidative or osmotic stress, respectively), we observed a significant survival benefit in RGNEF-transfected HEK293T cells. Using deletion constructs, we found that the NH2-terminus domain is essential for this protective effect. Interestingly, we observed that under stress conditions RGNEF associates with Staufen1 positive granules but not TIA-1-positive stress granules. These findings support the hypothesis that RGNEF plays a critical role both in RNA homeostasis and in the response to cell stress.
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19
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McLaughlin RL, Kenna KP, Vajda A, Heverin M, Byrne S, Donaghy CG, Cronin S, Bradley DG, Hardiman O. Homozygosity mapping in an Irish ALS case–control cohort describes local demographic phenomena and points towards potential recessive risk loci. Genomics 2015; 105:237-41. [DOI: 10.1016/j.ygeno.2015.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 01/07/2015] [Accepted: 01/16/2015] [Indexed: 12/19/2022]
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20
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Changes in TDP-43 expression in development, aging, and in the neurofilament light protein knockout mouse. Neurobiol Aging 2015; 36:1151-9. [DOI: 10.1016/j.neurobiolaging.2014.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/30/2014] [Accepted: 10/03/2014] [Indexed: 12/12/2022]
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21
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Yuan M, Gao S, Sun C, Chen L, Shi Q, Hu J, Yu R, Zhou X. Inhibiting geranylgeranyltransferase I activity decreases spine density in central nervous system. Hippocampus 2014; 25:373-84. [PMID: 25330763 DOI: 10.1002/hipo.22379] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2014] [Indexed: 12/20/2022]
Abstract
Geranylgeranyltransferase I (GGT), a protein prenyltransferase, is responsible for the posttranslational lipidation of Rho GTPases, such as Rac, Rho and Cdc42, all of which play an important role in neuronal synaptogenesis. We previously demonstrated that GGT promotes dendritic morphogenesis in cultured hippocampal neurons and cerebellar slices. We report here that inhibiting GGT activity decreases basal- and activity-dependent changes in spine density as well as in learning and memory ability of mice in vivo. We found that KCl- or bicuculline-induced dendritic spine density increases was abolished by specific GGT inhibitor GGTi-2147 treatment in cultured hippocampal neurons. GGTi-2147 lateral ventricular injection reduced GGT activity and membrane association of Rac and decreased the density of dendritic spines in the mouse hippocampus, frontal cortex and cerebellum. GGTi-2147 administration also impaired learning and memory ability of mice. More importantly, mice exposed to environmental enrichment (EE) showed increased spine density and learning and memory ability, which were significantly reversed by GGTi-2147 administration. These data demonstrate that inhibiting GGT activity prevents both basal- and activity-dependent changes in spine density in central nervous system both in vitro and in vivo. Manipulating GGT activity may be a promising strategy for the therapies of neurodevelopmental disorders, such as autism, depression, and schizophrenia.
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Affiliation(s)
- Maochun Yuan
- The Graduate School, Xuzhou Medical College, Xuzhou, Jiangsu, China
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22
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Miller NLG, Kleinschmidt EG, Schlaepfer DD. RhoGEFs in cell motility: novel links between Rgnef and focal adhesion kinase. Curr Mol Med 2014; 14:221-34. [PMID: 24467206 DOI: 10.2174/1566524014666140128110339] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 07/08/2013] [Accepted: 12/02/2013] [Indexed: 11/22/2022]
Abstract
Rho guanine exchange factors (GEFs) are a large, diverse family of proteins defined by their ability to catalyze the exchange of GDP for GTP on small GTPase proteins such as Rho family members. GEFs act as integrators from varied intra- and extracellular sources to promote spatiotemporal activity of Rho GTPases that control signaling pathways regulating cell proliferation and movement. Here we review recent studies elucidating roles of RhoGEF proteins in cell motility. Emphasis is placed on Dbl-family GEFs and connections to development, integrin signaling to Rho GTPases regulating cell adhesion and movement, and how these signals may enhance tumor progression. Moreover, RhoGEFs have additional domains that confer distinctive functions or specificity. We will focus on a unique interaction between Rgnef (also termed Arhgef28 or p190RhoGEF) and focal adhesion kinase (FAK), a non-receptor tyrosine kinase that controls migration properties of normal and tumor cells. This Rgnef-FAK interaction activates canonical GEF-dependent RhoA GTPase activity to govern contractility and also functions as a scaffold in a GEF-independent manner to enhance FAK activation. Recent studies have also brought to light the importance of specific regions within the Rgnef pleckstrin homology (PH) domain for targeting the membrane. As revealed by ongoing Rgnef-FAK investigations, exploring GEF roles in cancer will yield fundamental new information on the molecular mechanisms promoting tumor spread and metastasis.
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Affiliation(s)
| | | | - D D Schlaepfer
- University of California San Diego, Moores Cancer Center, Department of Reproductive Medicine, MC 0803, 3855 Health Sciences Dr., La Jolla, CA 92093 USA.
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23
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Stankiewicz TR, Linseman DA. Rho family GTPases: key players in neuronal development, neuronal survival, and neurodegeneration. Front Cell Neurosci 2014; 8:314. [PMID: 25339865 PMCID: PMC4187614 DOI: 10.3389/fncel.2014.00314] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/18/2014] [Indexed: 12/11/2022] Open
Abstract
The Rho family of GTPases belongs to the Ras superfamily of low molecular weight (∼21 kDa) guanine nucleotide binding proteins. The most extensively studied members are RhoA, Rac1, and Cdc42. In the last few decades, studies have demonstrated that Rho family GTPases are important regulatory molecules that link surface receptors to the organization of the actin and microtubule cytoskeletons. Indeed, Rho GTPases mediate many diverse critical cellular processes, such as gene transcription, cell–cell adhesion, and cell cycle progression. However, Rho GTPases also play an essential role in regulating neuronal morphology. In particular, Rho GTPases regulate dendritic arborization, spine morphogenesis, growth cone development, and axon guidance. In addition, more recent efforts have underscored an important function for Rho GTPases in regulating neuronal survival and death. Interestingly, Rho GTPases can exert either a pro-survival or pro-death signal in neurons depending upon both the cell type and neurotoxic insult involved. This review summarizes key findings delineating the involvement of Rho GTPases and their effectors in the regulation of neuronal survival and death. Collectively, these results suggest that dysregulation of Rho family GTPases may potentially underscore the etiology of some forms of neurodegenerative disease such as amyotrophic lateral sclerosis.
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Affiliation(s)
- Trisha R Stankiewicz
- Research Service, Veterans Affairs Medical Center Denver, CO, USA ; Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver Denver, CO, USA
| | - Daniel A Linseman
- Research Service, Veterans Affairs Medical Center Denver, CO, USA ; Department of Biological Sciences and Eleanor Roosevelt Institute, University of Denver Denver, CO, USA ; Division of Clinical Pharmacology and Toxicology, Department of Medicine and Neuroscience Program, University of Colorado Denver Aurora, CO, USA
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24
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Campos-Melo D, Droppelmann CA, Volkening K, Strong MJ. RNA-binding proteins as molecular links between cancer and neurodegeneration. Biogerontology 2014; 15:587-610. [PMID: 25231915 DOI: 10.1007/s10522-014-9531-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 09/11/2014] [Indexed: 12/12/2022]
Abstract
For many years, epidemiological studies have suggested an association between cancer and neurodegenerative disorders-two disease processes that seemingly have little in common. Although these two disease processes share disruptions in a wide range of cellular pathways, including cell survival, cell death and the cell cycle, the end result is very divergent: uncontrolled cell survival and proliferation in cancer and progressive neuronal cell death in neurodegeneration. Despite the clinical data connecting these two disease processes, little is known about the molecular links between them. Among the mechanisms affected in cancer and neurodegenerative diseases, alterations in RNA metabolism are obtaining significant attention given the critical role for RNA transcription, maturation, transport, stability, degradation and translation in normal cellular function. RNA-binding proteins (RBPs) are integral to each stage of RNA metabolism through their participation in the formation of ribonucleoprotein complexes (RNPs). RBPs have a broad range of functions including posttranscriptional regulation of mRNA stability, splicing, editing and translation, mRNA export and localization, mRNA polyadenylation and miRNA biogenesis, ultimately impacting the expression of every single gene in the cell. In this review, we examine the evidence for RBPs as being key a molecular linkages between cancer and neurodegeneration.
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Affiliation(s)
- Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Western University, London, ON, Canada
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Droppelmann CA, Campos-Melo D, Volkening K, Strong MJ. The emerging role of guanine nucleotide exchange factors in ALS and other neurodegenerative diseases. Front Cell Neurosci 2014; 8:282. [PMID: 25309324 PMCID: PMC4159981 DOI: 10.3389/fncel.2014.00282] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/25/2014] [Indexed: 12/11/2022] Open
Abstract
Small GTPases participate in a broad range of cellular processes such as proliferation, differentiation, and migration. The exchange of GDP for GTP resulting in the activation of these GTPases is catalyzed by a group of enzymes called guanine nucleotide exchange factors (GEFs), of which two classes: Dbl-related exchange factors and the more recently described dedicator of cytokinesis proteins family exchange factors. Increasingly, deregulation of normal GEF activity or function has been associated with a broad range of disease states, including neurodegeneration and neurodevelopmental disorders. In this review, we examine this evidence with special emphasis on the novel role of Rho guanine nucleotide exchange factor (RGNEF/p190RhoGEF) in the pathogenesis of amyotrophic lateral sclerosis. RGNEF is the first neurodegeneration-linked GEF that regulates not only RhoA GTPase activation but also functions as an RNA binding protein that directly acts with low molecular weight neurofilament mRNA 3' untranslated region to regulate its stability. This dual role for RGNEF, coupled with the increasing understanding of the key role for GEFs in modulating the GTPase function in cell survival suggests a prominent role for GEFs in mediating a critical balance between cytotoxicity and neuroprotection which, when disturbed, contributes to neuronal loss.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada
| | - Danae Campos-Melo
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada
| | - Kathryn Volkening
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada ; Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University London, ON, Canada
| | - Michael J Strong
- Molecular Medicine Group, Robarts Research Institute, Western University London, ON, Canada ; Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University London, ON, Canada
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Droppelmann CA, Campos-Melo D, Ishtiaq M, Volkening K, Strong MJ. RNA metabolism in ALS: When normal processes become pathological. Amyotroph Lateral Scler Frontotemporal Degener 2014; 15:321-36. [DOI: 10.3109/21678421.2014.881377] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Ishtiaq M, Campos-Melo D, Volkening K, Strong MJ. Analysis of novel NEFL mRNA targeting microRNAs in amyotrophic lateral sclerosis. PLoS One 2014; 9:e85653. [PMID: 24454911 PMCID: PMC3893244 DOI: 10.1371/journal.pone.0085653] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/29/2013] [Indexed: 02/02/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by progressive motor neuron degeneration and neurofilament aggregate formation. Spinal motor neurons in ALS also show a selective suppression in the levels of low molecular weight neurofilament (NEFL) mRNA. We have been interested in investigating the role of microRNAs (miRNAs) in NEFL transcript stability. MiRNAs are small, 20–25 nucleotide, non-coding RNAs that act as post-transcriptional gene regulators by targeting the 3′ untranslated region (3′UTR) of mRNA resulting in mRNA decay or translational silencing. In this study, we characterized putative novel miRNAs from a small RNA library derived from control and sporadic ALS (sALS) spinal cords. We detected 80 putative novel miRNAs, 24 of which have miRNA response elements (MREs) within the NEFL mRNA 3′UTR. From this group, we determined by real-time PCR that 10 miRNAs were differentially expressed in sALS compared to controls. Functional analysis by reporter gene assay and relative quantitative RT-PCR showed that two novel miRNAs, miR-b1336 and miR-b2403, were downregulated in ALS spinal cord and that both stabilize NEFL mRNA. We confirmed the direct effect of these latter miRNAs using anit-miR-b1336 and anti-miR-b2403. These results demonstrate that the expression of two miRNAs (miRNAs miR-b1336 and miR-b2403) whose effect is to stabilize NEFL mRNA are down regulated in ALS, the net effect of which is predicted to contribute directly to the loss of NEFL steady state mRNA which is pathognomic of spinal motor neurons in ALS.
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Affiliation(s)
- Muhammad Ishtiaq
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
| | - Danae Campos-Melo
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
| | - Kathryn Volkening
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Michael J. Strong
- Molecular Medicine Research Group, Robarts Research Institute, Western University, London, Ontario, Canada
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- * E-mail:
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Campos-Melo D, Droppelmann CA, He Z, Volkening K, Strong MJ. Altered microRNA expression profile in Amyotrophic Lateral Sclerosis: a role in the regulation of NFL mRNA levels. Mol Brain 2013; 6:26. [PMID: 23705811 PMCID: PMC3668997 DOI: 10.1186/1756-6606-6-26] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 05/22/2013] [Indexed: 12/12/2022] Open
Abstract
Background Amyotrophic Lateral Sclerosis (ALS) is a progressive, adult onset, fatal neurodegenerative disease of motor neurons. There is emerging evidence that alterations in RNA metabolism may be critical in the pathogenesis of ALS. MicroRNAs (miRNAs) are small non-coding RNAs that are key determinants of mRNA stability. Considering that miRNAs are increasingly being recognized as having a role in a variety of neurodegenerative diseases, we decided to characterize the miRNA expression profile in spinal cord (SC) tissue in sporadic ALS (sALS) and controls. Furthermore, we performed functional analysis to identify a group of dysregulated miRNAs that could be responsible for the selective suppression of low molecular weight neurofilament (NFL) mRNA observed in ALS. Results Using TaqMan arrays we analyzed 664 miRNAs and found that a large number of miRNAs are differentially expressed in ventral lumbar SC in sALS compared to controls. We observed that the majority of dysregulated miRNAs are down-regulated in sALS SC tissues. Ingenuity Pathway Analysis (IPA) showed that dysregulated miRNAs are linked with nervous system function and cell death. We used two prediction algorithms to develop a panel of miRNAs that have recognition elements within the human NFL mRNA 3′UTR, and then we performed functional analysis for these miRNAs. Our results demonstrate that three miRNAs that are dysregulated in sALS (miR-146a*, miR-524-5p and miR-582-3p) are capable of interacting with NFL mRNA 3′UTR in a manner that is consistent with the suppressed steady state mRNA levels observed in spinal motor neurons in ALS. Conclusions The miRNA expression profile is broadly altered in the SC in sALS. Amongst these is a group of dysregulated miRNAs directly regulate the NFL mRNA 3′UTR, suggesting a role in the selective suppression of NFL mRNA in the ALS spinal motor neuron neurofilamentous aggregate formation.
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Affiliation(s)
- Danae Campos-Melo
- Molecular Brain Research Group, Robarts Research Institute, University of Western Ontario, London, ON, Canada
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Droppelmann CA, Wang J, Campos-Melo D, Keller B, Volkening K, Hegele RA, Strong MJ. Detection of a novel frameshift mutation and regions with homozygosis within ARHGEF28 gene in familial amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:444-51. [PMID: 23286752 DOI: 10.3109/21678421.2012.758288] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Rho guanine nucleotide exchange factor (RGNEF) is a novel NFL mRNA destabilizing factor that forms neuronal cytoplasmic inclusions in spinal motor neurons in both sporadic (SALS) and familial (FALS) ALS patients. Given the observation of genetic mutations in a number of mRNA binding proteins associated with ALS, including TDP-43, FUS/TLS and mtSOD1, we analysed the ARHGEF28 gene (approx. 316 kb) that encodes for RGNEF in FALS cases to determine if mutations were present. We performed genomic sequencing, copy number variation analysis using TaqMan real-time PCR and spinal motor neuron immunohistochemistry using a novel RGNEF antibody. In this limited sample of FALS cases (n=7) we identified a heterozygous mutation that is predicted to generate a premature truncated gene product. We also observed extensive regions of homozygosity in the ARHGEF28 gene in two FALS patients. In conclusion, our findings of genetic alterations in the ARHGEF28 gene in cases of FALS suggest that a more comprehensive genetic analysis would be warranted.
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Affiliation(s)
- Cristian A Droppelmann
- Molecular Brain Research Group, Robarts Research Institute , University of Western Ontario, London, Ontario
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