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Wei C, Benzow K, Koob MD, Gomez CM, Du X. The Transcription Factor, α1ACT, Acts Through a MicroRNA Network to Regulate Neurogenesis and Cell Death During Neonatal Cerebellar Development. CEREBELLUM (LONDON, ENGLAND) 2023; 22:651-662. [PMID: 35729466 PMCID: PMC10307715 DOI: 10.1007/s12311-022-01431-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/09/2022] [Indexed: 11/29/2022]
Abstract
MicroRNAs, a class of small RNA regulators, function throughout neurodevelopment, from neural stem cell neurogenesis to neuronal maturation, synaptic formation, and plasticity. α1ACT, a transcription factor (TF), plays a critical role in neonatal cerebellar development by regulating an ensemble of genes. Of these, ChIP-seq analysis matched near 50% genes directly regulated by α1ACT. Yet, more than half the regulated transcripts lacked direct interaction with α1ACT. To investigate whether α1ACT acts through a microRNA network, we studied α1ACT-associated simultaneous miRNA:mRNA transcriptome profiles, using miRNA-seq paired with RNA-seq. Thirty-one differentially expressed miRNAs (DEMs) associated with α1ACT-regulated differentially expressed genes (DEGs) were profiled in α1ACT-overexpressing PC12 cells and were further validated in neonatal transgenic mouse cerebellum overexpressing α1ACT in a context-dependent manner. Here, we also demonstrated that α1ACT facilitates neurogenesis and development of dendritic synapses and is partially a result of the downregulation of the miR-99 cluster, miR-143, miR-23, miR-146, miR-363, and miR-484. On the other hand, the miR-181, miR-125, and miR-708 clusters were upregulated by α1ACT, which inhibit MAPK signaling and cell death pathways by targeting Ask1, Odc1, Atf4, and Nuf2 for decreased expression. MiR-181a-5p was verified as the most abundant DEM in neonatal cerebellum, which was further induced by α1ACT. Overall, under α1ACT modulation, up-/downregulated miRNA clusters with their paired target genes may form a regulatory network controlling the balance between the neuronal proliferation, differentiation, and cell death in the cerebellum to promote neonatal development. Our findings concerning the α1ACT-related miRNA/mRNA expression profiles in neonatal cerebellum may inform future investigations for cerebellar development.
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Affiliation(s)
- Cenfu Wei
- Department of Neurology, University of Chicago, Chicago, IL, 60637, USA
| | - Kellie Benzow
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Michael D Koob
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, 55455, USA
| | | | - Xiaofei Du
- Department of Neurology, University of Chicago, Chicago, IL, 60637, USA.
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2
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Riboldi GM, Faravelli I, Rinchetti P, Lotti F. SMN post-translational modifications in spinal muscular atrophy. Front Cell Neurosci 2023; 17:1092488. [PMID: 36874214 PMCID: PMC9981653 DOI: 10.3389/fncel.2023.1092488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/26/2023] [Indexed: 02/19/2023] Open
Abstract
Since its first identification as the gene responsible for spinal muscular atrophy (SMA), the range of survival motor neuron (SMN) protein functions has increasingly expanded. This multimeric complex plays a crucial role in a variety of RNA processing pathways. While its most characterized function is in the biogenesis of ribonucleoproteins, several studies have highlighted the SMN complex as an important contributor to mRNA trafficking and translation, axonal transport, endocytosis, and mitochondria metabolism. All these multiple functions need to be selectively and finely modulated to maintain cellular homeostasis. SMN has distinct functional domains that play a crucial role in complex stability, function, and subcellular distribution. Many different processes were reported as modulators of the SMN complex activities, although their contribution to SMN biology still needs to be elucidated. Recent evidence has identified post-translational modifications (PTMs) as a way to regulate the pleiotropic functions of the SMN complex. These modifications include phosphorylation, methylation, ubiquitination, acetylation, sumoylation, and many other types. PTMs can broaden the range of protein functions by binding chemical moieties to specific amino acids, thus modulating several cellular processes. Here, we provide an overview of the main PTMs involved in the regulation of the SMN complex with a major focus on the functions that have been linked to SMA pathogenesis.
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Affiliation(s)
| | | | | | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY, United States
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3
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Detering NT, Schüning T, Hensel N, Claus P. The phospho-landscape of the survival of motoneuron protein (SMN) protein: relevance for spinal muscular atrophy (SMA). Cell Mol Life Sci 2022; 79:497. [PMID: 36006469 PMCID: PMC11071818 DOI: 10.1007/s00018-022-04522-9] [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: 03/21/2022] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 11/03/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of the survival of motoneuron (SMN) Protein leading to preferential degeneration of lower motoneurons in the ventral horn of the spinal cord and brain stem. However, the SMN protein is ubiquitously expressed and there is growing evidence of a multisystem phenotype in SMA. Since a loss of SMN function is critical, it is important to decipher the regulatory mechanisms of SMN function starting on the level of the SMN protein itself. Posttranslational modifications (PTMs) of proteins regulate multiple functions and processes, including activity, cellular trafficking, and stability. Several PTM sites have been identified within the SMN sequence. Here, we map the identified SMN PTMs highlighting phosphorylation as a key regulator affecting localization, stability and functions of SMN. Furthermore, we propose SMN phosphorylation as a crucial factor for intracellular interaction and cellular distribution of SMN. We outline the relevance of phosphorylation of the spinal muscular atrophy (SMA) gene product SMN with regard to basic housekeeping functions of SMN impaired in this neurodegenerative disease. Finally, we compare SMA patient mutations with putative and verified phosphorylation sites. Thus, we emphasize the importance of phosphorylation as a cellular modulator in a clinical perspective as a potential additional target for combinatorial SMA treatment strategies.
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Affiliation(s)
- Nora Tula Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Tobias Schüning
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Niko Hensel
- Ottawa Hospital Research Institute (OHRI), Ottawa, Canada
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany.
- Center for Systems Neuroscience (ZSN), Hannover, Germany.
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4
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Transcriptomic Analysis of MAPK Signaling in NSC-34 Motor Neurons Treated with Vitamin E. Nutrients 2019; 11:nu11051081. [PMID: 31096690 PMCID: PMC6566669 DOI: 10.3390/nu11051081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/08/2019] [Accepted: 05/10/2019] [Indexed: 12/14/2022] Open
Abstract
Vitamin E family is composed of different tocopherols and tocotrienols that are well-known as antioxidants but that exert also non-antioxidant effects. Oxidative stress may be involved in the progression of neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), characterized by motor neuron death. The aim of the study was the evaluation of the changes induced in the transcriptional profile of NSC-34 motor neurons treated with α-tocopherol. In particular, cells were treated for 24 h with 10 µM α-tocopherol, RNA was extracted and transcriptomic analysis was performed using Next Generation Sequencing. Vitamin E treatment modulated MAPK signaling pathway. The evaluation revealed that 34 and 12 genes, respectively belonging to “Classical MAP kinase pathway” and “JNK and p38 MAP kinase pathway”, were involved. In particular, a downregulation of the genes encoding for p38 (Log2 fold change −0.87 and −0.67) and JNK (Log2 fold change −0.16) was found. On the contrary, the gene encoding for ERK showed a higher expression in cells treated with vitamin E (Log2 fold change 0.30). Since p38 and JNK seem more involved in cell death, while ERK in cell survival, the data suggested that vitamin E treatment may exert a protective role in NSC-34 motor neurons. Moreover, Vitamin E treatment reduced the expression of the genes which encode proteins involved in mitophagy. These results indicate that vitamin E may be an efficacious therapy in preventing motor neuron death, opening new strategies for those diseases that involve motor neurons, including ALS.
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5
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Maretina MA, Zheleznyakova GY, Lanko KM, Egorova AA, Baranov VS, Kiselev AV. Molecular Factors Involved in Spinal Muscular Atrophy Pathways as Possible Disease-modifying Candidates. Curr Genomics 2018; 19:339-355. [PMID: 30065610 PMCID: PMC6030859 DOI: 10.2174/1389202919666180101154916] [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: 09/18/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by mutations in the SMN1 gene. Being a monogenic disease, it is characterized by high clinical heterogeneity. Variations in penetrance and severity of symptoms, as well as clinical discrepancies between affected family members can result from modifier genes influence on disease manifestation. SMN2 gene copy number is known to be the main phenotype modifier and there is growing evidence of additional factors contributing to SMA severity. Potential modifiers of spinal muscular atrophy can be found among the wide variety of different factors, such as multiple proteins interacting with SMN or promoting motor neuron survival, epigenetic modifications, transcriptional or splicing factors influencing SMN2 expression. Study of these factors enables to reveal mechanisms underlying SMA pathology and can have pronounced clinical application.
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Affiliation(s)
- Marianna A. Maretina
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Galina Y. Zheleznyakova
- Department of Clinical Neuroscience, Karolinska Institutet, Karolinska Universitetssjukhuset, 171 76 Stockholm, Sweden
| | - Kristina M. Lanko
- Saint Petersburg State Institute of Technology, Moskovsky prospect, 26, Saint Petersburg190013, Russia
| | - Anna A. Egorova
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
| | - Vladislav S. Baranov
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Anton V. Kiselev
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
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6
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Kim EK, Choi EJ. SMN1 functions as a novel inhibitor for TRAF6-mediated NF-κB signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:760-770. [DOI: 10.1016/j.bbamcr.2017.02.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 02/10/2017] [Accepted: 02/14/2017] [Indexed: 12/30/2022]
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7
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Wertz MH, Winden K, Neveu P, Ng SY, Ercan E, Sahin M. Cell-type-specific miR-431 dysregulation in a motor neuron model of spinal muscular atrophy. Hum Mol Genet 2016; 25:2168-2181. [PMID: 27005422 DOI: 10.1093/hmg/ddw084] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/11/2016] [Indexed: 12/17/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal-recessive pediatric neurodegenerative disease characterized by selective loss of spinal motor neurons. It is caused by mutation in the survival of motor neuron 1, SMN1, gene and leads to loss of function of the full-length SMN protein. microRNAs (miRNAs) are small RNAs that are involved in post-transcriptional regulation of gene expression. Prior studies have implicated miRNAs in the pathogenesis of motor neuron disease. We hypothesized that motor neuron-specific miRNA expression changes are involved in their selective vulnerability in SMA. Therefore, we sought to determine the effect of SMN loss on miRNAs and their target mRNAs in spinal motor neurons. We used microarray and RNAseq to profile both miRNA and mRNA expression in primary spinal motor neuron cultures after acute SMN knockdown. By integrating the miRNA:mRNA profiles, a number of dysregulated miRNAs were identified with enrichment in differentially expressed putative mRNA targets. miR-431 expression was highly increased, and a number of its putative mRNA targets were significantly downregulated in motor neurons after SMN loss. Further, we found that miR-431 regulates motor neuron neurite length by targeting several molecules previously identified to play a role in motor neuron axon outgrowth, including chondrolectin. Together, our findings indicate that cell-type-specific dysregulation of miR-431 plays a role in the SMA motor neuron phenotype.
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Affiliation(s)
- Mary H Wertz
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kellen Winden
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Pierre Neveu
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Shi-Yan Ng
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA Neurotherapeutics Laboratory, Institute of Molecular and Cell Biology, A*STAR, Singapore 138673, Singapore
| | - Ebru Ercan
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mustafa Sahin
- Department of Neurology, The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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8
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Federspiel JD, Codreanu SG, Palubinsky AM, Winland AJ, Betanzos CM, McLaughlin B, Liebler DC. Assembly Dynamics and Stoichiometry of the Apoptosis Signal-regulating Kinase (ASK) Signalosome in Response to Electrophile Stress. Mol Cell Proteomics 2016; 15:1947-61. [PMID: 27006476 DOI: 10.1074/mcp.m115.057364] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Indexed: 01/29/2023] Open
Abstract
Apoptosis signal-regulating kinase 1 (ASK1) is a key sensor kinase in the mitogen-activated protein kinase pathway that transduces cellular responses to oxidants and electrophiles. ASK1 is regulated by a large, dynamic multiprotein signalosome complex, potentially including over 90 reported ASK1-interacting proteins. We employed both shotgun and targeted mass spectrometry assays to catalogue the ASK1 protein-protein interactions in HEK-293 cells treated with the prototypical lipid electrophile 4-hydroxy-2-nonenal (HNE). Using both epitope-tagged overexpression and endogenous expression cell systems, we verified most of the previously reported ASK1 protein-protein interactions and identified 14 proteins that exhibited dynamic shifts in association with ASK1 in response to HNE stress. We used precise stable isotope dilution assays to quantify protein stoichiometry in the ASK signalosome complex and identified ASK2 at a 1:1 stoichiometric ratio with ASK1 and 14-3-3 proteins (YWHAQ, YWHAB, YWHAH, and YWHAE) collectively at a 0.5:1 ratio with ASK1 as the main components. Several other proteins, including ASK3, PARK7, PRDX1, and USP9X were detected with stoichiometries of 0.1:1 or less. These data support an ASK signalosome comprising a multimeric core complex of ASK1, ASK2, and 14-3-3 proteins, which dynamically engages other binding partners needed to mediate diverse stress-response signaling events. This study further demonstrates the value of combining global and targeted MS approaches to interrogate multiprotein complex composition and dynamics.
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Affiliation(s)
- Joel D Federspiel
- From the ‡Department of Biochemistry, Vanderbilt University School of Medicine
| | - Simona G Codreanu
- From the ‡Department of Biochemistry, Vanderbilt University School of Medicine
| | - Amy M Palubinsky
- §Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University
| | - Ama J Winland
- ¶Department of Neurology, Vanderbilt University, Nashville, Tennessee, 37232
| | | | - BethAnn McLaughlin
- ¶Department of Neurology, Vanderbilt University, Nashville, Tennessee, 37232
| | - Daniel C Liebler
- From the ‡Department of Biochemistry, Vanderbilt University School of Medicine;
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9
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Li H, Custer SK, Gilson T, Hao LT, Beattie CE, Androphy EJ. α-COP binding to the survival motor neuron protein SMN is required for neuronal process outgrowth. Hum Mol Genet 2015; 24:7295-307. [PMID: 26464491 DOI: 10.1093/hmg/ddv428] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/06/2015] [Indexed: 01/30/2023] Open
Abstract
Spinal muscular atrophy (SMA), a heritable neurodegenerative disease, results from insufficient levels of the survival motor neuron (SMN) protein. α-COP binds to SMN, linking the COPI vesicular transport pathway to SMA. Reduced levels of α-COP restricted development of neuronal processes in NSC-34 cells and primary cortical neurons. Remarkably, heterologous expression of human α-COP restored normal neurite length and morphology in SMN-depleted NSC-34 cells in vitro and zebrafish motor neurons in vivo. We identified single amino acid mutants of α-COP that selectively abrogate SMN binding, retain COPI-mediated Golgi-ER trafficking functionality, but were unable to support neurite outgrowth in cellular and zebrafish models of SMA. Taken together, these demonstrate the functional role of COPI association with the SMN protein in neuronal development.
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Affiliation(s)
- Hongxia Li
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
| | - Sara K Custer
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
| | - Timra Gilson
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
| | - Le Thi Hao
- Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA
| | - Christine E Beattie
- Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
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10
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Locatelli D, Terao M, Kurosaki M, Zanellati MC, Pletto DR, Finardi A, Colciaghi F, Garattini E, Battaglia GS. Different Stability and Proteasome-Mediated Degradation Rate of SMN Protein Isoforms. PLoS One 2015. [PMID: 26214005 PMCID: PMC4516248 DOI: 10.1371/journal.pone.0134163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The key pathogenic steps leading to spinal muscular atrophy (SMA), a genetic disease characterized by selective motor neuron degeneration, are not fully clarified. The full-length SMN protein (FL-SMN), the main protein product of the disease gene SMN1, plays an established role in the cytoplasm in snRNP biogenesis ultimately leading to mRNA splicing within the nucleus. It is also involved in the mRNA axonal transport. However, to what extent the impairment of these two SMN functions contributes to SMA pathogenesis remains unknown. A shorter SMN isoform, axonal-SMN or a-SMN, with more specific axonal localization, has been discovered, but whether it might act in concert with FL-SMN in SMA pathogenesis is not known. As a first step in defining common or divergent intracellular roles of FL-SMN vs a-SMN proteins, we here characterized the turn-over of both proteins and investigated which pathway contributed to a-SMN degradation. We performed real time western blot and confocal immunofluorescence analysis in easily controllable in vitro settings. We analyzed co-transfected NSC34 and HeLa cells and cell clones stably expressing both a-SMN and FL-SMN proteins after specific blocking of transcript or protein synthesis and inhibition of known intracellular degradation pathways. Our data indicated that whereas the stability of both FL-SMN and a-SMN transcripts was comparable, the a-SMN protein was characterized by a much shorter half-life than FL-SMN. In addition, as already demonstrated for FL-SMN, the Ub/proteasome pathway played a major role in the a-SMN protein degradation. We hypothesize that the faster degradation rate of a-SMN vs FL-SMN is related to the protection provided by the protein complex in which FL-SMN is assembled. The diverse a-SMN vs FL-SMN C-terminus may dictate different protein interactions and complex formation explaining the different localization and role in the neuronal compartment, and the lower expression and stability of a-SMN.
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Affiliation(s)
- Denise Locatelli
- Molecular Neuroanatomy and Pathogenesis Unit, IRCCS Neurological Institute “C. Besta”, Milano, Italy
- * E-mail:
| | - Mineko Terao
- Laboratory of Molecular Biology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Mami Kurosaki
- Laboratory of Molecular Biology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Maria Clara Zanellati
- Molecular Neuroanatomy and Pathogenesis Unit, IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Daniela Rita Pletto
- Molecular Neuroanatomy and Pathogenesis Unit, IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Adele Finardi
- Molecular Neuroanatomy and Pathogenesis Unit, IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Francesca Colciaghi
- Molecular Neuroanatomy and Pathogenesis Unit, IRCCS Neurological Institute “C. Besta”, Milano, Italy
| | - Enrico Garattini
- Laboratory of Molecular Biology, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy
| | - Giorgio Stefano Battaglia
- Molecular Neuroanatomy and Pathogenesis Unit, IRCCS Neurological Institute “C. Besta”, Milano, Italy
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11
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Hensel N, Stockbrügger I, Rademacher S, Broughton N, Brinkmann H, Grothe C, Claus P. Bilateral crosstalk of rho- and extracellular-signal-regulated-kinase (ERK) pathways is confined to an unidirectional mode in spinal muscular atrophy (SMA). Cell Signal 2013; 26:540-8. [PMID: 24316236 DOI: 10.1016/j.cellsig.2013.11.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/15/2013] [Accepted: 11/26/2013] [Indexed: 10/26/2022]
Abstract
Rho-kinase (ROCK) as well as extracellular signal regulated kinase (ERK) control actin cytoskeletal organization thereby regulating dynamic changes of cellular morphology. In neurons, motility processes such as axonal guidance and neurite outgrowth demand a fine regulation of upstream pathways. Here we demonstrate a bilateral ROCK-ERK information flow in neurons. This process is shifted towards an unidirectional crosstalk in a model of the neurodegenerative disease Spinal Muscular Atrophy (SMA), ultimately leading to neurite outgrowth dysregulations. As both pathways are of therapeutic relevance for SMA, our results argue for a combinatorial ROCK/ERK-targeting as a future treatment strategy.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Inga Stockbrügger
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Sebastian Rademacher
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Natasha Broughton
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, 30625 Hannover, Germany; Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany; Niedersachsen Research Network on Neuroinfection (N-RENNT), Germany.
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Sleigh JN, Barreiro-Iglesias A, Oliver PL, Biba A, Becker T, Davies KE, Becker CG, Talbot K. Chondrolectin affects cell survival and neuronal outgrowth in in vitro and in vivo models of spinal muscular atrophy. Hum Mol Genet 2013; 23:855-69. [PMID: 24067532 DOI: 10.1093/hmg/ddt477] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by the selective loss of spinal motor neurons owing to reduced levels of survival motor neuron (Smn) protein. In addition to its well-established role in assembling constituents of the spliceosome, diverse cellular functions have been proposed for Smn, but the reason why low levels of this widely expressed protein result in selective motor neuron pathology is still debated. In longitudinal studies of exon-level changes in SMA mouse model tissues, designed to determine the contribution of splicing dysfunction to the disease, we have previously shown that a generalized defect in splicing is unlikely to play a causative role in SMA. Nevertheless, we identified a small subset of genes that were alternatively spliced in the spinal cord compared with control mice before symptom onset, indicating a possible mechanistic role in disease. Here, we have performed functional studies of one of these genes, chondrolectin (Chodl), known to be highly expressed in motor neurons and important for correct motor axon outgrowth in zebrafish. Using in vitro and in vivo models of SMA, we demonstrate altered expression of Chodl in SMA mouse spinal motor neurons, show that Chodl has distinct effects on cell survival and neurite outgrowth and that increasing the expression of chodl can rescue motor neuron outgrowth defects in Smn-depleted zebrafish. Our findings thus link the dysregulation of Chodl to the pathophysiology of motor neuron degeneration in SMA.
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Affiliation(s)
- James N Sleigh
- Department of Physiology, Anatomy and Genetics, MRC Functional Genomics Unit, University of Oxford, South Parks Road, Oxford OX1 3PT, UK
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Genetic circuitry of Survival motor neuron, the gene underlying spinal muscular atrophy. Proc Natl Acad Sci U S A 2013; 110:E2371-80. [PMID: 23757500 DOI: 10.1073/pnas.1301738110] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The clinical severity of the neurodegenerative disorder spinal muscular atrophy (SMA) is dependent on the levels of functional Survival Motor Neuron (SMN) protein. Consequently, current strategies for developing treatments for SMA generally focus on augmenting SMN levels. To identify additional potential therapeutic avenues and achieve a greater understanding of SMN, we applied in vivo, in vitro, and in silico approaches to identify genetic and biochemical interactors of the Drosophila SMN homolog. We identified more than 300 candidate genes that alter an Smn-dependent phenotype in vivo. Integrating the results from our genetic screens, large-scale protein interaction studies, and bioinformatic analysis, we define a unique interactome for SMN that provides a knowledge base for a better understanding of SMA.
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