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Sachdev A, Gill K, Sckaff M, Birk AM, Aladesuyi Arogundade O, Brown KA, Chouhan RS, Issagholian-Lewin PO, Patel E, Watry HL, Bernardi MT, Keough KC, Tsai YC, Smith AST, Conklin BR, Clelland CD. Reversal of C9orf72 mutation-induced transcriptional dysregulation and pathology in cultured human neurons by allele-specific excision. Proc Natl Acad Sci U S A 2024; 121:e2307814121. [PMID: 38621131 PMCID: PMC11047104 DOI: 10.1073/pnas.2307814121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 03/01/2024] [Indexed: 04/17/2024] Open
Abstract
Efforts to genetically reverse C9orf72 pathology have been hampered by our incomplete understanding of the regulation of this complex locus. We generated five different genomic excisions at the C9orf72 locus in a patient-derived induced pluripotent stem cell (iPSC) line and a non-diseased wild-type (WT) line (11 total isogenic lines), and examined gene expression and pathological hallmarks of C9 frontotemporal dementia/amyotrophic lateral sclerosis in motor neurons differentiated from these lines. Comparing the excisions in these isogenic series removed the confounding effects of different genomic backgrounds and allowed us to probe the effects of specific genomic changes. A coding single nucleotide polymorphism in the patient cell line allowed us to distinguish transcripts from the normal vs. mutant allele. Using digital droplet PCR (ddPCR), we determined that transcription from the mutant allele is upregulated at least 10-fold, and that sense transcription is independently regulated from each allele. Surprisingly, excision of the WT allele increased pathologic dipeptide repeat poly-GP expression from the mutant allele. Importantly, a single allele was sufficient to supply a normal amount of protein, suggesting that the C9orf72 gene is haplo-sufficient in induced motor neurons. Excision of the mutant repeat expansion reverted all pathology (RNA abnormalities, dipeptide repeat production, and TDP-43 pathology) and improved electrophysiological function, whereas silencing sense expression did not eliminate all dipeptide repeat proteins, presumably because of the antisense expression. These data increase our understanding of C9orf72 gene regulation and inform gene therapy approaches, including antisense oligonucleotides (ASOs) and CRISPR gene editing.
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Affiliation(s)
| | - Kamaljot Gill
- Gladstone Institutes, San Francisco, CA94158
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
| | - Maria Sckaff
- Gladstone Institutes, San Francisco, CA94158
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
| | | | - Olubankole Aladesuyi Arogundade
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
- Memory & Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA94158
| | - Katherine A. Brown
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
- Memory & Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA94158
| | - Runvir S. Chouhan
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
- Memory & Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA94158
| | - Patrick Oliver Issagholian-Lewin
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
- Memory & Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA94158
| | - Esha Patel
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
- Memory & Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA94158
| | | | | | | | | | - Alec Simon Tulloch Smith
- Department of Physiology and Biophysics, University of Washington, Seattle, WA98195
- The Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA98195
| | - Bruce R. Conklin
- Gladstone Institutes, San Francisco, CA94158
- Department of Medicine, University of California San Francisco, San Francisco, CA94143
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA94143
- Department of Pharmacology, University of California San Francisco, San Francisco, CA94158
| | - Claire Dudley Clelland
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA94158
- Memory & Aging Center, Department of Neurology, University of California San Francisco, San Francisco, CA94158
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McAleer CW, Smith AST, Najjar S, Pirozzi K, Long CJ, Hickman JJ. Mechanistic investigation of adult myotube response to exercise and drug treatment in vitro using a multiplexed functional assay system. J Appl Physiol (1985) 2014; 117:1398-405. [PMID: 25301895 DOI: 10.1152/japplphysiol.00612.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The ability to accurately measure skeletal muscle functional performance at the single-cell level would be advantageous for exercise physiology studies and disease modeling applications. To that end, this study characterizes the functional response of individual skeletal muscle myotubes derived from adult rodent tissue to creatine treatment and chronic exercise. The observed improvements to functional performance in response to these treatments appear to correlate with alterations in hypertrophic and mitochondrial biogenesis pathways, supporting previously published in vivo and in vitro data, which highlights the role of these pathways in augmenting skeletal muscle output. The developed system represents a multiplexed functional in vitro assay capable of long-term assessment of contractile cellular outputs in real-time that is compatible with concomitant molecular biology analysis. Adoption of this system in drug toxicity and efficacy studies would improve understanding of compound activity on physical cellular outputs and provide more streamlined and predictive data for future preclinical analyses.
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Affiliation(s)
- C W McAleer
- NanoScience Technology Center, University of Central Florida, Orlando, Florida
| | - A S T Smith
- NanoScience Technology Center, University of Central Florida, Orlando, Florida
| | - S Najjar
- NanoScience Technology Center, University of Central Florida, Orlando, Florida
| | - K Pirozzi
- NanoScience Technology Center, University of Central Florida, Orlando, Florida
| | - C J Long
- NanoScience Technology Center, University of Central Florida, Orlando, Florida
| | - J J Hickman
- NanoScience Technology Center, University of Central Florida, Orlando, Florida
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Smith AST, Long CJ, Pirozzi K, Najjar S, McAleer C, Vandenburgh HH, Hickman JJ. A multiplexed chip-based assay system for investigating the functional development of human skeletal myotubes in vitro. J Biotechnol 2014; 185:15-8. [PMID: 24909944 DOI: 10.1016/j.jbiotec.2014.05.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/19/2014] [Accepted: 05/23/2014] [Indexed: 11/24/2022]
Abstract
This report details the development of a non-invasive in vitro assay system for investigating the functional maturation and performance of human skeletal myotubes. Data is presented demonstrating the survival and differentiation of human myotubes on microscale silicon cantilevers in a defined, serum-free system. These cultures can be stimulated electrically and the resulting contraction quantified using modified atomic force microscopy technology. This system provides a higher degree of sensitivity for investigating contractile waveforms than video-based analysis, and represents the first system capable of measuring the contractile activity of individual human muscle myotubes in a reliable, high-throughput and non-invasive manner. The development of such a technique is critical for the advancement of body-on-a-chip platforms toward application in pre-clinical drug development screens.
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Affiliation(s)
- A S T Smith
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA
| | - C J Long
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA
| | - K Pirozzi
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA
| | - S Najjar
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA
| | - C McAleer
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA
| | - H H Vandenburgh
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI 02906, USA
| | - J J Hickman
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA.
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Pirozzi KL, Long CJ, McAleer CW, Smith AST, Hickman JJ. Correlation of embryonic skeletal muscle myotube physical characteristics with contractile force generation on an atomic force microscope-based bio-microelectromechanical systems device. Appl Phys Lett 2013; 103:83108. [PMID: 24046483 PMCID: PMC3765224 DOI: 10.1063/1.4817939] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 07/23/2013] [Indexed: 05/27/2023]
Abstract
Rigorous analysis of muscle function in in vitro systems is needed for both acute and chronic biomedical applications. Forces generated by skeletal myotubes on bio-microelectromechanical cantilevers were calculated using a modified version of Stoney's thin-film equation and finite element analysis (FEA), then analyzed for regression to physical parameters. The Stoney's equation results closely matched the more intensive FEA and the force correlated to cross-sectional area (CSA). Normalizing force to measured CSA significantly improved the statistical sensitivity and now allows for close comparison of in vitro data to in vivo measurements for applications in exercise physiology, robotics, and modeling neuromuscular diseases.
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Affiliation(s)
- K L Pirozzi
- NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, USA
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Mudera V, Smith AST, Brady MA, Lewis MP. The effect of cell density on the maturation and contractile ability of muscle derived cells in a 3D tissue-engineered skeletal muscle model and determination of the cellular and mechanical stimuli required for the synthesis of a postural phenotype. J Cell Physiol 2010; 225:646-53. [PMID: 20533296 DOI: 10.1002/jcp.22271] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The successful engineering of a truly biomimetic model of skeletal muscle could have a significant impact on a number of biomedical disciplines. Although a variety of techniques are currently being developed, there is, as of yet, no widely available and easily reproducible culture system for the synthesis of 3D artificial muscle tissues. In attempting to generate such a model it is essential to optimise any protocol in order to generate a tissue that best represents the in vivo environment. Since the maturation of muscle derived cells in culture is critically dependent on density, a major factor to be addressed in the development of these models is the ideal concentration at which to seed cells in order to generate an optimal response. In studying the effect of cell density on the performance of cells in an established 3D collagen based model of skeletal muscle, we demonstrate that an optimum density does exist in terms of peak force generation and myogenic gene expression data. Greater densities however, lead to the formation of a more physiologically relevant tissue with a phenotype characteristic of slow, postural muscle.
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Affiliation(s)
- V Mudera
- UCL Institute of Orthopaedics and Musculoskeletal Science, London, UK
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