1
|
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.
Collapse
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
| |
Collapse
|
2
|
Zhang D, Hao W, Niu Q, Xu D, Duan X. Identification of the co-differentially expressed hub genes involved in the endogenous protective mechanism against ventilator-induced diaphragm dysfunction. Skelet Muscle 2022; 12:21. [PMID: 36085166 PMCID: PMC9461262 DOI: 10.1186/s13395-022-00304-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 08/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In intensive care units (ICU), mechanical ventilation (MV) is commonly applied to save patients' lives. However, ventilator-induced diaphragm dysfunction (VIDD) can complicate treatment by hindering weaning in critically ill patients and worsening outcomes. The goal of this study was to identify potential genes involved in the endogenous protective mechanism against VIDD. METHODS Twelve adult male rabbits were assigned to either an MV group or a control group under the same anesthetic conditions. Immunostaining and quantitative morphometry were used to assess diaphragm atrophy, while RNA-seq was used to investigate molecular differences between the groups. Additionally, core module and hub genes were analyzed using WGCNA, and co-differentially expressed hub genes were subsequently discovered by overlapping the differentially expressed genes (DEGs) with the hub genes from WGCNA. The identified genes were validated by western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS After a VIDD model was successfully built, 1276 DEGs were found between the MV and control groups. The turquoise and yellow modules were identified as the core modules, and Trim63, Fbxo32, Uchl1, Tmprss13, and Cst3 were identified as the five co-differentially expressed hub genes. After the two atrophy-related genes (Trim63 and Fbxo32) were excluded, the levels of the remaining three genes/proteins (Uchl1/UCHL1, Tmprss13/TMPRSS13, and Cst3/CST3) were found to be significantly elevated in the MV group (P < 0.05), suggesting the existence of a potential antiproteasomal, antiapoptotic, and antiautophagic mechanism against diaphragm dysfunction. CONCLUSION The current research helps to reveal a potentially important endogenous protective mechanism that could serve as a novel therapeutic target against VIDD.
Collapse
Affiliation(s)
- Dong Zhang
- Department of Critical Care Medicine, Heping Hospital Affiliated to Changzhi Medical College, 110 South Yan'an Road, Luzhou District, Changzhi, 046012, China.
| | - Wenyan Hao
- Department of Biomedical Engineering, Changzhi Medical College, Changzhi, 046012, China
| | - Qi Niu
- Department of Critical Care Medicine, Heping Hospital Affiliated to Changzhi Medical College, 110 South Yan'an Road, Luzhou District, Changzhi, 046012, China
| | - Dongdong Xu
- Department of Critical Care Medicine, Heping Hospital Affiliated to Changzhi Medical College, 110 South Yan'an Road, Luzhou District, Changzhi, 046012, China
| | - Xuejiao Duan
- Department of Critical Care Medicine, Heping Hospital Affiliated to Changzhi Medical College, 110 South Yan'an Road, Luzhou District, Changzhi, 046012, China
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Liu S, Hu G, Luo S, Wu W, Zhou Q, Jin R, Zhang Y, Ruan H, Huang H, Li H. Insights into the evolution of the ISG15 and UBA7 system. Genomics 2022; 114:110302. [DOI: 10.1016/j.ygeno.2022.110302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 01/08/2022] [Accepted: 02/01/2022] [Indexed: 11/04/2022]
|
5
|
Abstract
Ubiquitin C-terminal Hydrolase L1 (UCHL1) is a deubiquitinating enzyme that was originally identified in neurons. Our recent study showed that UCHL1 was expressed in C2C12 myoblast cells and mouse skeletal muscle. Here we report that in mouse skeletal muscle, UCHL1 is primarily expressed in oxidative muscle fibers. Skeletal muscle specific gene knockout (smKO) of UCHL1 in mice reduced oxidative activity in skeletal muscle measured by SDH staining. The in situ muscle contraction test revealed that gastrocnemius muscle from UCHL1 smKO mice was more prone to fatigue in response to the repetitive stimulation. This data suggests that UCHL1 plays a role in maintenance of muscle oxidative metabolism. Moreover, UCHL1 smKO caused a significant reduction in key proteins that are involved in mitochondrial oxidative phosphorylation in soleus muscles, suggesting that UCHL1 may be involved in regulation of mitochondrial content and function. Immunostaining showed the co-localization of UCHL1 and mitochondrial marker VDAC in skeletal muscle. Mitochondrial fractionation assay revealed that, although UCHL1 was primarily present in the cytosolic fraction, a low level of UCHL1 protein was present in mitochondrial fraction. The level of phosphorylation of AMPKα, a master regulator of mitochondrial biogenesis, were unchanged in UCHL1 smKO muscle. On the other hand, immunoprecipitation from soleus muscle sample indicated the interaction between UCHL1 and HSP60, a chaperon protein that is involved in mitochondrial protein transport. There was a trend of downregulation of HSP60 in UCHL1 smKO muscle. Overall, our data suggests UCHL1 is a novel regulator of mitochondrial function and oxidative activity in skeletal muscle.
Collapse
|
6
|
Matuszczak E, Tylicka M, Komarowska MD, Debek W, Hermanowicz A. Ubiquitin carboxy-terminal hydrolase L1 - physiology and pathology. Cell Biochem Funct 2020; 38:533-540. [PMID: 32207552 DOI: 10.1002/cbf.3527] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/20/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
Ubiquitin C-terminal hydrolase 1 (UCHL1) is an enzyme unique for its multiple activity - both ligase and hydrolase. UCHL1 was first identified as an abundant protein found in the brain and testes, however its expression is not limited to the neuronal compartment. UCHL1 is also highly expressed in carcinomas of various tissue origins, including those from brain, lung, breast, kidney, colon, prostate, pancreas and mesenchymal tissues. Loss-of-function studies and an inhibitor for UCHL1 confirmed the importance of UCHL1 for cancer therapy. So far biological significance of UCHL1 was described in the following processes: spermatogenesis, oncogenesis, angiogenesis, cell proliferation and differentiation in skeletal muscle, inflammation, tissue injury, neuronal injury and neurodegeneration.
Collapse
Affiliation(s)
- Ewa Matuszczak
- Pediatric Surgery Department, Medical University of Bialystok, Bialystok, Poland
| | - Marzena Tylicka
- Biophysics Department, Medical University of Bialystok, Bialystok, Poland
| | | | - Wojciech Debek
- Pediatric Surgery Department, Medical University of Bialystok, Bialystok, Poland
| | - Adam Hermanowicz
- Pediatric Surgery Department, Medical University of Bialystok, Bialystok, Poland
| |
Collapse
|
7
|
Plasma ubiquitin C-terminal hydrolase L1 levels reflect disease stage and motor severity in Parkinson's disease. Aging (Albany NY) 2020; 12:1488-1495. [PMID: 31932518 PMCID: PMC7053593 DOI: 10.18632/aging.102695] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 12/25/2019] [Indexed: 01/10/2023]
Abstract
Parkinson’s disease (PD) is characterized by Lewy bodies containing α-synuclein and ubiquitin aggregates, their co-occurrence possibly linked to a failure of the ubiquitin proteasome system. Ubiquitin C-terminal hydrolase L1 (UCHL1) plays an important role in maintenance of nervous system integrity, and overexpression of UCHL1 has been shown to increase ubiquitin levels within neurons. While cerebrospinal fluid ubiquitin levels were reported to be lower in PD vs controls, plasma UCHL1 levels and their relationship with clinical measures in PD has not been reported. We measured plasma UCHL1 levels using single molecule array (Simoa) in 291 subjects (242 PD and 49 healthy controls, HC). We found that UCHL1 levels were significantly higher in PD patients at moderate stages (Hoehn and Yahr, H&Y stage >2) vs milder PD (H&Y ≤2, p<0.001) and HC (p=0.001). There was no significant difference in UCHL1 levels between PD patients at H&Y stages ≤2 vs HC. Across all PD patients, UCHL1 correlated significantly with UPDRS Part III motor scores (β=3.87, 95% CI=0.43-7.31, p=0.028), but not with global cognition. Overall, we found that UCHL1 correlates with motor function in PD, with higher levels seen in later disease stages. These findings will be validated in longitudinal studies.
Collapse
|
8
|
Zhu S, Wuolikainen A, Wu J, Öhman A, Wingsle G, Moritz T, Andersen PM, Forsgren L, Trupp M. Targeted Multiple Reaction Monitoring Analysis of CSF Identifies UCHL1 and GPNMB as Candidate Biomarkers for ALS. J Mol Neurosci 2019; 69:643-657. [PMID: 31721001 PMCID: PMC6858390 DOI: 10.1007/s12031-019-01411-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 09/26/2019] [Indexed: 02/06/2023]
Abstract
The neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and Parkinson’s disease (PD) share some common molecular deficits including disruption of protein homeostasis leading to disease-specific protein aggregation. While insoluble protein aggregates are the defining pathological confirmation of diagnosis, patient stratification based on early molecular etiologies may identify distinct subgroups within a clinical diagnosis that would respond differently in therapeutic development programs. We are developing targeted multiple reaction monitoring (MRM) mass spectrometry methods to rigorously quantify CSF proteins from known disease genes involved in lysosomal, ubiquitin-proteasomal, and autophagy pathways. Analysis of CSF from 21 PD, 21 ALS, and 25 control patients, rigorously matched for gender, age, and age of sample, revealed significant changes in peptide levels between PD, ALS, and control. In patients with PD, levels of two peptides for chromogranin B (CHGB, secretogranin 1) were significantly reduced. In CSF of patients with ALS, levels of two peptides from ubiquitin carboxy-terminal hydrolase like protein 1 (UCHL1) and one peptide each for glycoprotein non-metastatic melanoma protein B (GPNMB) and cathepsin D (CTSD) were all increased. Analysis of patients with ALS separated into two groups based on length of survival after CSF sampling revealed that the increases in GPNMB and UCHL1 were specific for short-lived ALS patients. While analysis of additional cohorts is required to validate these candidate biomarkers, this study suggests methods for stratification of ALS patients for clinical trials and identifies targets for drug efficacy measurements during therapeutic development.
Collapse
Affiliation(s)
- Shaochun Zhu
- Department of Clinical Science, Neurosciences, Umeå University, Building 10, NUS, Umeå, Sweden
| | | | - Junfang Wu
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Anders Öhman
- Department of Clinical Science, Neurosciences, Umeå University, Building 10, NUS, Umeå, Sweden
| | - Gunnar Wingsle
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Peter M Andersen
- Department of Clinical Science, Neurosciences, Umeå University, Building 10, NUS, Umeå, Sweden
| | - Lars Forsgren
- Department of Clinical Science, Neurosciences, Umeå University, Building 10, NUS, Umeå, Sweden
| | - Miles Trupp
- Department of Clinical Science, Neurosciences, Umeå University, Building 10, NUS, Umeå, Sweden.
| |
Collapse
|
9
|
UCHL1 regulates muscle fibers and mTORC1 activity in skeletal muscle. Life Sci 2019; 233:116699. [PMID: 31356902 DOI: 10.1016/j.lfs.2019.116699] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/23/2019] [Accepted: 07/25/2019] [Indexed: 01/25/2023]
Abstract
AIMS Skeletal muscle wasting is associated with many chronic diseases. Effective prevention and treatment of muscle wasting remain as a challenging task due to incomplete understanding of mechanisms by which muscle mass is maintained and regulated. This study investigated the functional role of Ubiquitin C-terminal hydrolase L1 (UCHL1) in skeletal muscle. MAIN METHODS Mice with skeletal muscle specific gene knockout of UCHL1 and C2C12 myoblast cells with UCHL1 knockdown were used. Muscle fiber types and size were measured using tissue or cell staining. The mammalian target of rapamycin complex 1 (mTORC1) and mTORC2 activities were assessed with the phosphorylation of their downstream targets. KEY FINDINGS In mouse skeletal muscle, UCHL1 was primarily expressed in slow twitch muscle fibers. Mice with skeletal muscle specific knockout (skmKO) of UCHL1 exhibited enlarged muscle fiber sizes in slow twitch soleus but not fast twitch extensor digitorum longus (EDL) muscle. Meanwhile, UCHL1 skmKO enhanced mTORC1 activity and reduced mTORC2 activity in soleus but not in EDL. Consistently, in C2C12 cells, UCHL1 knockdown increased the myotube size, enhanced mTORC1 activity, and reduced mTORC2 activities as compared with control cells. UCHL1 knockdown did not change the major proteins of mTOR complex but decreased the protein turnover of PRAS40, an inhibitory factor of mTORC1. SIGNIFICANCE These data revealed a novel function of UCHL1 in regulation of mTORC1 activity and skeletal muscle growth in slow twitch skeletal muscle. Given the upregulation of UCHL1 in denervation and spinal muscle atrophy, our finding advances understanding of regulators that are involved in muscle wasting.
Collapse
|
10
|
Chaytow H, Huang YT, Gillingwater TH, Faller KME. The role of survival motor neuron protein (SMN) in protein homeostasis. Cell Mol Life Sci 2018; 75:3877-3894. [PMID: 29872871 PMCID: PMC6182345 DOI: 10.1007/s00018-018-2849-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022]
Abstract
Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.
Collapse
Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.
| | - Kiterie M E Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
11
|
Reddy SS, Shruthi K, Prabhakar YK, Sailaja G, Reddy GB. Implication of altered ubiquitin-proteasome system and ER stress in the muscle atrophy of diabetic rats. Arch Biochem Biophys 2018; 639:16-25. [DOI: 10.1016/j.abb.2017.12.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 12/13/2017] [Accepted: 12/20/2017] [Indexed: 02/07/2023]
|
12
|
Gao H, Hartnett S, Li Y. Ubiquitin C-Terminal Hydrolase L1 regulates myoblast proliferation and differentiation. Biochem Biophys Res Commun 2017; 492:96-102. [PMID: 28803986 DOI: 10.1016/j.bbrc.2017.08.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 08/08/2017] [Indexed: 01/03/2023]
Abstract
Skeletal muscles are dynamic tissues that possess regenerative abilities, which require multiple processes and regulatory factors. Ubiquitin C-Terminal Hydrolase L1 (UCHL1), which is primarily expressed in neuronal tissues, was upregulated in skeletal muscles in disease conditions but its functional role in skeletal muscles is unknown. Using mouse myoblast cells C2C12 as an in vitro model, this study reported that UCHL1 elicits different regulation in myoblast cell proliferation and differentiation. We first observed that UCHL1 protein level was continuously declined during cell differentiation. Gene knockdown of UCHL1 by siRNA resulted in a significant decrease in cell proliferation but marked acceleration of cell differentiation and myotube formation. Meanwhile, UCHL1 gene knockdown upregulated myogenic factors myoD and Myogenin (MyoG). In mice, UCHL1 was significantly upregulated in denervated skeletal muscle. Overall, these novel data suggest that UCHL1 may play a role in myogenesis by promoting myoblast proliferation and inhibiting differentiation.
Collapse
Affiliation(s)
- Hongbo Gao
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, 414 East Clark Street, Lee Med Building, Vermillion, SD 57069, USA
| | - Sigurd Hartnett
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, 414 East Clark Street, Lee Med Building, Vermillion, SD 57069, USA
| | - Yifan Li
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, 414 East Clark Street, Lee Med Building, Vermillion, SD 57069, USA.
| |
Collapse
|
13
|
Blondelle J, Shapiro P, Domenighetti AA, Lange S. Cullin E3 Ligase Activity Is Required for Myoblast Differentiation. J Mol Biol 2017; 429:1045-1066. [PMID: 28238764 DOI: 10.1016/j.jmb.2017.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/17/2017] [Accepted: 02/18/2017] [Indexed: 01/06/2023]
Abstract
The role of cullin E3-ubiquitin ligases for muscle homeostasis is best known during muscle atrophy, as the cullin-1 substrate adaptor atrogin-1 is among the most well-characterized muscle atrogins. We investigated whether cullin activity was also crucial during terminal myoblast differentiation and aggregation of acetylcholine receptors for the establishment of neuromuscular junctions in vitro. The activity of cullin E3-ligases is modulated through post-translational modification with the small ubiquitin-like modifier nedd8. Using either the Nae1 inhibitor MLN4924 (Pevonedistat) or siRNA against nedd8 in early or late stages of differentiation on C2C12 myoblasts, and primary satellite cells from mouse and human, we show that cullin E3-ligase activity is necessary for each step of the muscle cell differentiation program in vitro. We further investigate known transcriptional repressors for terminal muscle differentiation, namely ZBTB38, Bhlhe41, and Id1. Due to their identified roles for terminal muscle differentiation, we hypothesize that the accumulation of these potential cullin E3-ligase substrates may be partially responsible for the observed phenotype. MLN4924 is currently undergoing clinical trials in cancer patients, and our experiments highlight concerns on the homeostasis and regenerative capacity of muscles in these patients who often experience cachexia.
Collapse
Affiliation(s)
- Jordan Blondelle
- Division of Cardiology, University of California San Diego, La Jolla, CA-92093 USA
| | - Paige Shapiro
- Division of Cardiology, University of California San Diego, La Jolla, CA-92093 USA
| | - Andrea A Domenighetti
- Rehabilitation Institute of Chicago, Chicago, IL-60611 USA; Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL-60611, USA
| | - Stephan Lange
- Division of Cardiology, University of California San Diego, La Jolla, CA-92093 USA.
| |
Collapse
|
14
|
Hebert MD, Poole AR. Towards an understanding of regulating Cajal body activity by protein modification. RNA Biol 2016; 14:761-778. [PMID: 27819531 DOI: 10.1080/15476286.2016.1243649] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The biogenesis of small nuclear ribonucleoproteins (snRNPs), small Cajal body-specific RNPs (scaRNPs), small nucleolar RNPs (snoRNPs) and the telomerase RNP involves Cajal bodies (CBs). Although many components enriched in the CB contain post-translational modifications (PTMs), little is known about how these modifications impact individual protein function within the CB and, in concert with other modified factors, collectively regulate CB activity. Since all components of the CB also reside in other cellular locations, it is also important that we understand how PTMs affect the subcellular localization of CB components. In this review, we explore the current knowledge of PTMs on the activity of proteins known to enrich in CBs in an effort to highlight current progress as well as illuminate paths for future investigation.
Collapse
Affiliation(s)
- Michael D Hebert
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Aaron R Poole
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| |
Collapse
|
15
|
Fuller HR, Gillingwater TH, Wishart TM. Commonality amid diversity: Multi-study proteomic identification of conserved disease mechanisms in spinal muscular atrophy. Neuromuscul Disord 2016; 26:560-9. [PMID: 27460344 DOI: 10.1016/j.nmd.2016.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 06/03/2016] [Indexed: 01/09/2023]
Abstract
The neuromuscular disease spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality, resulting from low levels of full-length survival motor neuron (SMN) protein. Despite having a good understanding of the underlying genetics of SMA, the molecular pathways downstream of SMN that regulate disease pathogenesis remain unclear. The identification of molecular perturbations downstream of SMN is required in order to fully understand the fundamental biological role(s) for SMN in cells and tissues of the body, as well as to develop a range of therapeutic targets for developing novel treatments for SMA. Recent developments in proteomic screening technologies have facilitated proteome-wide investigations of a range of SMA models and tissues, generating novel insights into disease mechanisms by highlighting conserved changes in a range of molecular pathways. Comparative analysis of distinct proteomic datasets reveals conserved changes in pathways converging on GAP43, GAPDH, NCAM, UBA1, LMNA, ANXA2 and COL6A3. Proteomic studies therefore represent a leading tool with which to dissect the molecular mechanisms of disease pathogenesis in SMA, serving to identify potentially attractive targets for the development of novel therapies.
Collapse
Affiliation(s)
- Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK; Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK.
| | - Thomas H Gillingwater
- Centre for Integrative Physiology, University of Edinburgh, UK; Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, UK
| | - Thomas M Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, UK; Division of Neurobiology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, UK.
| |
Collapse
|
16
|
Powis RA, Karyka E, Boyd P, Côme J, Jones RA, Zheng Y, Szunyogova E, Groen EJ, Hunter G, Thomson D, Wishart TM, Becker CG, Parson SH, Martinat C, Azzouz M, Gillingwater TH. Systemic restoration of UBA1 ameliorates disease in spinal muscular atrophy. JCI Insight 2016; 1:e87908. [PMID: 27699224 PMCID: PMC5033939 DOI: 10.1172/jci.insight.87908] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The autosomal recessive neuromuscular disease spinal muscular atrophy (SMA) is caused by loss of survival motor neuron (SMN) protein. Molecular pathways that are disrupted downstream of SMN therefore represent potentially attractive therapeutic targets for SMA. Here, we demonstrate that therapeutic targeting of ubiquitin pathways disrupted as a consequence of SMN depletion, by increasing levels of one key ubiquitination enzyme (ubiquitin-like modifier activating enzyme 1 [UBA1]), represents a viable approach for treating SMA. Loss of UBA1 was a conserved response across mouse and zebrafish models of SMA as well as in patient induced pluripotent stem cell-derive motor neurons. Restoration of UBA1 was sufficient to rescue motor axon pathology and restore motor performance in SMA zebrafish. Adeno-associated virus serotype 9-UBA1 (AAV9-UBA1) gene therapy delivered systemic increases in UBA1 protein levels that were well tolerated over a prolonged period in healthy control mice. Systemic restoration of UBA1 in SMA mice ameliorated weight loss, increased survival and motor performance, and improved neuromuscular and organ pathology. AAV9-UBA1 therapy was also sufficient to reverse the widespread molecular perturbations in ubiquitin homeostasis that occur during SMA. We conclude that UBA1 represents a safe and effective therapeutic target for the treatment of both neuromuscular and systemic aspects of SMA.
Collapse
Affiliation(s)
- Rachael A. Powis
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Evangelia Karyka
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Penelope Boyd
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Julien Côme
- INSERM/UEVE UMR861, Institute for Stem cell Therapy and Exploration of Monogenic Diseases (I-Stem), Corbeil-Essonnes, France
| | - Ross A. Jones
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Yinan Zheng
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Eva Szunyogova
- Euan MacDonald Centre for Motor Neurone Disease Research and,The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Ewout J.N. Groen
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Gillian Hunter
- Euan MacDonald Centre for Motor Neurone Disease Research and,Department of Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | | | - Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research and,The Roslin Institute, and
| | - Catherina G. Becker
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research and,The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Cécile Martinat
- INSERM/UEVE UMR861, Institute for Stem cell Therapy and Exploration of Monogenic Diseases (I-Stem), Corbeil-Essonnes, France
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and,Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
17
|
Groen EJN, Gillingwater TH. UBA1: At the Crossroads of Ubiquitin Homeostasis and Neurodegeneration. Trends Mol Med 2016; 21:622-632. [PMID: 26432019 PMCID: PMC4596250 DOI: 10.1016/j.molmed.2015.08.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/06/2015] [Accepted: 08/10/2015] [Indexed: 12/14/2022]
Abstract
Neurodegenerative diseases are a leading cause of disability and early death. A common feature of these conditions is disruption of protein homeostasis. Ubiquitin-like modifier activating enzyme 1 (UBA1), the E1 ubiquitin-activating enzyme, sits at the apex of the ubiquitin cascade and represents an important regulator of cellular protein homeostasis. Critical contributions of UBA1-dependent pathways to the regulation of homeostasis and degeneration in the nervous system are emerging, including specific disruption of UBA1 in spinal muscular atrophy (SMA) and Huntington's disease (HD). In this review we discuss recent findings that put UBA1 at the centre of cellular homeostasis and neurodegeneration, highlighting the potential for UBA1 to act as a promising therapeutic target for a range of neurodegenerative diseases.
Collapse
Affiliation(s)
- Ewout J N Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
| |
Collapse
|
18
|
Yang CW, Chen CL, Chou WC, Lin HC, Jong YJ, Tsai LK, Chuang CY. An Integrative Transcriptomic Analysis for Identifying Novel Target Genes Corresponding to Severity Spectrum in Spinal Muscular Atrophy. PLoS One 2016; 11:e0157426. [PMID: 27331400 PMCID: PMC4917114 DOI: 10.1371/journal.pone.0157426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 05/31/2016] [Indexed: 12/31/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neuromuscular disease resulting from a recessive mutation in the SMN1 gene. This disease affects multiple organ systems with varying degrees of severity. Exploration of the molecular pathological changes occurring in different cell types in SMA is crucial for developing new therapies. This study collected 39 human microarray datasets from ArrayExpress and GEO databases to build an integrative transcriptomic analysis for recognizing novel SMA targets. The transcriptomic analysis was conducted through combining weighted correlation network analysis (WGCNA) for gene module detection, gene set enrichment analysis (GSEA) for functional categorization and filtration, and Cytoscape (visual interaction gene network analysis) for target gene identification. Seven novel target genes (Bmp4, Serpine1, Gata6, Ptgs2, Bcl2, IL6 and Cntn1) of SMA were revealed, and are all known in the regulation of TNFα for controlling neural, cardiac and bone development. Sequentially, the differentially expressed patterns of these 7 target genes in mouse tissues (e.g., spinal cord, heart, muscles and bone) were validated in SMA mice of different severities (pre-symptomatic, mildly symptomatic, and severely symptomatic). In severely symptomatic SMA mice, TNFα was up-regulated with attenuation of Bmp4 and increase of Serpine1 and Gata6 (a pathway in neural and cardiac development), but not in pre-symptomatic and mildly symptomatic SMA mice. The severely symptomatic SMA mice also had the elevated levels of Ptgs2 and Bcl2 (a pathway in skeletal development) as well as IL6 and Cntn1 (a pathway in nervous system development). Thus, the 7 genes identified in this study might serve as potential target genes for future investigations of disease pathogenesis and SMA therapy.
Collapse
Affiliation(s)
- Chung-Wei Yang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Chien-Lin Chen
- Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Wei-Chun Chou
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Ho-Chen Lin
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Yuh-Jyh Jong
- Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Departments of Pediatrics and Clinical Laboratory, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
| | - Li-Kai Tsai
- Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail: (LKT); (CYC)
| | - Chun-Yu Chuang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail: (LKT); (CYC)
| |
Collapse
|
19
|
Hunter G, Powis RA, Jones RA, Groen EJN, Shorrock HK, Lane FM, Zheng Y, Sherman DL, Brophy PJ, Gillingwater TH. Restoration of SMN in Schwann cells reverses myelination defects and improves neuromuscular function in spinal muscular atrophy. Hum Mol Genet 2016; 25:2853-2861. [PMID: 27170316 PMCID: PMC5181642 DOI: 10.1093/hmg/ddw141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/19/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by low levels of SMN protein, primarily affecting lower motor neurons. Recent evidence from SMA and related conditions suggests that glial cells can influence disease severity. Here, we investigated the role of glial cells in the peripheral nervous system by creating SMA mice selectively overexpressing SMN in myelinating Schwann cells (Smn−/−;SMN2tg/0;SMN1SC). Restoration of SMN protein levels restricted solely to Schwann cells reversed myelination defects, significantly improved neuromuscular function and ameliorated neuromuscular junction pathology in SMA mice. However, restoration of SMN in Schwann cells had no impact on motor neuron soma loss from the spinal cord or ongoing systemic and peripheral pathology. This study provides evidence for a defined, intrinsic contribution of glial cells to SMA disease pathogenesis and suggests that therapies designed to include Schwann cells in their target tissues are likely to be required in order to rescue myelination defects and associated disease symptoms.
Collapse
Affiliation(s)
- Gillian Hunter
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK,
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Rachael A Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Ross A Jones
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Ewout J N Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Fiona M Lane
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Yinan Zheng
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| | - Diane L Sherman
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Peter J Brophy
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK,
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, EH8 9XD, UK and
| |
Collapse
|
20
|
Fuller HR, Mandefro B, Shirran SL, Gross AR, Kaus AS, Botting CH, Morris GE, Sareen D. Spinal Muscular Atrophy Patient iPSC-Derived Motor Neurons Have Reduced Expression of Proteins Important in Neuronal Development. Front Cell Neurosci 2016; 9:506. [PMID: 26793058 PMCID: PMC4707261 DOI: 10.3389/fncel.2015.00506] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/15/2015] [Indexed: 11/15/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neuromuscular disease primarily characterized by degeneration of spinal motor neurons, and caused by reduced levels of the SMN protein. Previous studies to understand the proteomic consequences of reduced SMN have mostly utilized patient fibroblasts and animal models. We have derived human motor neurons from type I SMA and healthy controls by creating their induced pluripotent stem cells (iPSCs). Quantitative mass spectrometry of these cells revealed increased expression of 63 proteins in control motor neurons compared to respective fibroblasts, whereas 30 proteins were increased in SMA motor neurons vs. their fibroblasts. Notably, UBA1 was significantly decreased in SMA motor neurons, supporting evidence for ubiquitin pathway defects. Subcellular distribution of UBA1 was predominantly cytoplasmic in SMA motor neurons in contrast to nuclear in control motor neurons; suggestive of neurodevelopmental abnormalities. Many of the proteins that were decreased in SMA motor neurons, including beta III-tubulin and UCHL1, were associated with neurodevelopment and differentiation. These neuron-specific consequences of SMN depletion were not evident in fibroblasts, highlighting the importance of iPSC technology. The proteomic profiles identified here provide a useful resource to explore the molecular consequences of reduced SMN in motor neurons, and for the identification of novel biomarker and therapeutic targets for SMA.
Collapse
Affiliation(s)
- Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, The Robert Jones and Agnes Hunt Orthopaedic HospitalOswestry, UK; Institute for Science and Technology in Medicine, Keele UniversityStaffordshire, UK
| | - Berhan Mandefro
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA; iPSC Core, The David and Janet Polak Foundation Stem Cell Core LaboratoryLos Angeles, CA, USA
| | - Sally L Shirran
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews Fife, UK
| | - Andrew R Gross
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical Center Los Angeles, CA, USA
| | - Anjoscha S Kaus
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical Center Los Angeles, CA, USA
| | - Catherine H Botting
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews Fife, UK
| | - Glenn E Morris
- Wolfson Centre for Inherited Neuromuscular Disease, The Robert Jones and Agnes Hunt Orthopaedic HospitalOswestry, UK; Institute for Science and Technology in Medicine, Keele UniversityStaffordshire, UK
| | - Dhruv Sareen
- Board of Governors-Regenerative Medicine Institute, Cedars-Sinai Medical CenterLos Angeles, CA, USA; iPSC Core, The David and Janet Polak Foundation Stem Cell Core LaboratoryLos Angeles, CA, USA; Department of Biomedical Sciences, Cedars-Sinai Medical CenterLos Angeles, CA, USA
| |
Collapse
|
21
|
Powis RA, Gillingwater TH. Selective loss of alpha motor neurons with sparing of gamma motor neurons and spinal cord cholinergic neurons in a mouse model of spinal muscular atrophy. J Anat 2015; 228:443-51. [PMID: 26576026 DOI: 10.1111/joa.12419] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2015] [Indexed: 02/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease characterised primarily by loss of lower motor neurons from the ventral grey horn of the spinal cord and proximal muscle atrophy. Recent experiments utilising mouse models of SMA have demonstrated that not all motor neurons are equally susceptible to the disease, revealing that other populations of neurons can also be affected. Here, we have extended investigations of selective vulnerability of neuronal populations in the spinal cord of SMA mice to include comparative assessments of alpha motor neuron (α-MN) and gamma motor neuron (γ-MN) pools, as well as other populations of cholinergic neurons. Immunohistochemical analyses of late-symptomatic SMA mouse spinal cord revealed that numbers of α-MNs were significantly reduced at all levels of the spinal cord compared with controls, whereas numbers of γ-MNs remained stable. Likewise, the average size of α-MN cell somata was decreased in SMA mice with no change occurring in γ-MNs. Evaluation of other pools of spinal cord cholinergic neurons revealed that pre-ganglionic sympathetic neurons, central canal cluster interneurons, partition interneurons and preganglionic autonomic dorsal commissural nucleus neuron numbers all remained unaffected in SMA mice. Taken together, these findings indicate that α-MNs are uniquely vulnerable among cholinergic neuron populations in the SMA mouse spinal cord, with γ-MNs and other cholinergic neuronal populations being largely spared.
Collapse
Affiliation(s)
- Rachael A Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.,Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.,Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| |
Collapse
|