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Morris TA, Eldeen S, Tran RDH, Grosberg A. A comprehensive review of computational and image analysis techniques for quantitative evaluation of striated muscle tissue architecture. BIOPHYSICS REVIEWS 2022; 3:041302. [PMID: 36407035 PMCID: PMC9667907 DOI: 10.1063/5.0057434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Unbiased evaluation of morphology is crucial to understanding development, mechanics, and pathology of striated muscle tissues. Indeed, the ability of striated muscles to contract and the strength of their contraction is dependent on their tissue-, cellular-, and cytoskeletal-level organization. Accordingly, the study of striated muscles often requires imaging and assessing aspects of their architecture at multiple different spatial scales. While an expert may be able to qualitatively appraise tissues, it is imperative to have robust, repeatable tools to quantify striated myocyte morphology and behavior that can be used to compare across different labs and experiments. There has been a recent effort to define the criteria used by experts to evaluate striated myocyte architecture. In this review, we will describe metrics that have been developed to summarize distinct aspects of striated muscle architecture in multiple different tissues, imaged with various modalities. Additionally, we will provide an overview of metrics and image processing software that needs to be developed. Importantly to any lab working on striated muscle platforms, characterization of striated myocyte morphology using the image processing pipelines discussed in this review can be used to quantitatively evaluate striated muscle tissues and contribute to a robust understanding of the development and mechanics of striated muscles.
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Affiliation(s)
| | - Sarah Eldeen
- Center for Complex Biological Systems, University of California, Irvine, California 92697-2700, USA
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2
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Sherman WF, Asad M, Grosberg A. An Energetic Approach to Modeling Cytoskeletal Architecture in Maturing Cardiomyocytes. J Biomech Eng 2022; 144:021002. [PMID: 34382649 PMCID: PMC8547018 DOI: 10.1115/1.4052112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 07/28/2021] [Indexed: 02/03/2023]
Abstract
Through a variety of mechanisms, a healthy heart is able to regulate its structure and dynamics across multiple length scales. Disruption of these mechanisms can have a cascading effect, resulting in severe structural and/or functional changes that permeate across different length scales. Due to this hierarchical structure, there is interest in understanding how the components at the various scales coordinate and influence each other. However, much is unknown regarding how myofibril bundles are organized within a densely packed cell and the influence of the subcellular components on the architecture that is formed. To elucidate potential factors influencing cytoskeletal development, we proposed a computational model that integrated interactions at both the cellular and subcellular scale to predict the location of individual myofibril bundles that contributed to the formation of an energetically favorable cytoskeletal network. Our model was tested and validated using experimental metrics derived from analyzing single-cell cardiomyocytes. We demonstrated that our model-generated networks were capable of reproducing the variation observed in experimental cells at different length scales as a result of the stochasticity inherent in the different interactions between the various cellular components. Additionally, we showed that incorporating length-scale parameters resulted in physical constraints that directed cytoskeletal architecture toward a structurally consistent motif. Understanding the mechanisms guiding the formation and organization of the cytoskeleton in individual cardiomyocytes can aid tissue engineers toward developing functional cardiac tissue.
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Affiliation(s)
- William F. Sherman
- Center for Complex Biological Systems, Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, CA 92697
| | - Mira Asad
- Edwards Lifesciences Center for Advanced Cardiovascular Technology, Department of Biomedical Engineering, University of California, Irvine, CA 92697
| | - Anna Grosberg
- Edwards Lifesciences Center for Advanced Cardiovascular Technology, Department of Biomedical Engineering, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA 92697; Department of Chemical and Biomolecular Engineering, Center for Complex Biological Systems, University of California, Irvine, CA 92697
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3
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Mehrabi M, Morris TA, Cang Z, Nguyen CHH, Sha Y, Asad MN, Khachikyan N, Greene TL, Becker DM, Nie Q, Zaragoza MV, Grosberg A. A Study of Gene Expression, Structure, and Contractility of iPSC-Derived Cardiac Myocytes from a Family with Heart Disease due to LMNA Mutation. Ann Biomed Eng 2021; 49:3524-3539. [PMID: 34585335 PMCID: PMC8671287 DOI: 10.1007/s10439-021-02850-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 08/06/2021] [Indexed: 12/18/2022]
Abstract
Genetic mutations to the Lamin A/C gene (LMNA) can cause heart disease, but the mechanisms making cardiac tissues uniquely vulnerable to the mutations remain largely unknown. Further, patients with LMNA mutations have highly variable presentation of heart disease progression and type. In vitro patient-specific experiments could provide a powerful platform for studying this phenomenon, but the use of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) introduces heterogeneity in maturity and function thus complicating the interpretation of the results of any single experiment. We hypothesized that integrating single cell RNA sequencing (scRNA-seq) with analysis of the tissue architecture and contractile function would elucidate some of the probable mechanisms. To test this, we investigated five iPSC-CM lines, three controls and two patients with a (c.357-2A>G) mutation. The patient iPSC-CM tissues had significantly weaker stress generation potential than control iPSC-CM tissues demonstrating the viability of our in vitro approach. Through scRNA-seq, differentially expressed genes between control and patient lines were identified. Some of these genes, linked to quantitative structural and functional changes, were cardiac specific, explaining the targeted nature of the disease progression seen in patients. The results of this work demonstrate the utility of combining in vitro tools in exploring heart disease mechanics.
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Affiliation(s)
- Mehrsa Mehrabi
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.,UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA
| | - Tessa A Morris
- UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA.,Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA
| | - Zixuan Cang
- Department of Mathematics and Developmental & Cell Biology, University of California, Irvine, CA, 92697, USA.,The NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA, 92697, USA
| | - Cecilia H H Nguyen
- Genetics & Genomics Division, Department of Pediatrics, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Yutong Sha
- Department of Mathematics and Developmental & Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Mira N Asad
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.,UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA
| | - Nyree Khachikyan
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.,UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA
| | - Taylor L Greene
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.,UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA
| | - Danielle M Becker
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.,UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA
| | - Qing Nie
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA.,Department of Mathematics and Developmental & Cell Biology, University of California, Irvine, CA, 92697, USA.,The NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA, 92697, USA
| | - Michael V Zaragoza
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, CA, 92697, USA.,Genetics & Genomics Division, Department of Pediatrics, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Anna Grosberg
- Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA. .,UCI Edwards Lifesciences Foundation Cardiovascular Innovation and Research Center (CIRC), University of California, Irvine, CA, 92697, USA. .,Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA. .,The NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, CA, 92697, USA. .,Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA, 92697, USA. .,The Henry Samueli School of Engineering, University of California, Irvine, 2418 Engineering Hall, Irvine, CA, 92697, USA.
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Widyastuti HP, Norden-Krichmar TM, Grosberg A, Zaragoza MV. Gene expression profiling of fibroblasts in a family with LMNA-related cardiomyopathy reveals molecular pathways implicated in disease pathogenesis. BMC MEDICAL GENETICS 2020; 21:152. [PMID: 32698886 PMCID: PMC7374820 DOI: 10.1186/s12881-020-01088-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/06/2020] [Indexed: 12/22/2022]
Abstract
Background Intermediate filament proteins that construct the nuclear lamina of a cell include the Lamin A/C proteins encoded by the LMNA gene, and are implicated in fundamental processes such as nuclear structure, gene expression, and signal transduction. LMNA mutations predominantly affect mesoderm-derived cell lineages in diseases collectively termed as laminopathies that include dilated cardiomyopathy with conduction defects, different forms of muscular dystrophies, and premature aging syndromes as Hutchinson-Gilford Progeria Syndrome. At present, our understanding of the molecular mechanisms regulating tissue-specific manifestations of laminopathies are still limited. Methods To gain deeper insight into the molecular mechanism of a novel LMNA splice-site mutation (c.357-2A > G) in an affected family with cardiac disease, we conducted deep RNA sequencing and pathway analysis for nine fibroblast samples obtained from three patients with cardiomyopathy, three unaffected family members, and three unrelated, unaffected individuals. We validated our findings by quantitative PCR and protein studies. Results We identified eight significantly differentially expressed genes between the mutant and non-mutant fibroblasts, that included downregulated insulin growth factor binding factor protein 5 (IGFBP5) in patient samples. Pathway analysis showed involvement of the ERK/MAPK signaling pathway consistent with previous studies. We found no significant differences in gene expression for Lamin A/C and B-type lamins between the groups. In mutant fibroblasts, RNA-seq confirmed that only the LMNA wild type allele predominately was expressed, and Western Blot showed normal Lamin A/C protein levels. Conclusions IGFBP5 may contribute in maintaining signaling pathway homeostasis, which may lead to the absence of notable molecular and structural abnormalities in unaffected tissues such as fibroblasts. Compensatory mechanisms from other nuclear membrane proteins were not found. Our results also demonstrate that only one copy of the wild type allele is sufficient for normal levels of Lamin A/C protein to maintain physiological function in an unaffected cell type. This suggests that affected cell types such as cardiac tissues may be more sensitive to haploinsufficiency of Lamin A/C. These results provide insight into the molecular mechanism of disease with a possible explanation for the tissue specificity of LMNA-related dilated cardiomyopathy.
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Affiliation(s)
- Halida P Widyastuti
- UCI Cardiogenomics Program, Department of Pediatrics, Division of Genetics & Genomics and Department of Biological Chemistry, University of California, Irvine, School of Medicine, 2042 Hewitt Hall, Irvine, CA, 92697-3940, USA
| | - Trina M Norden-Krichmar
- Department of Epidemiology, University of California, Irvine, School of Medicine, 3062 Anteater Instruction and Research Building, Irvine, CA, 92697-7550, USA.
| | - Anna Grosberg
- Department of Biomedical Engineering and The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, California, USA
| | - Michael V Zaragoza
- UCI Cardiogenomics Program, Department of Pediatrics, Division of Genetics & Genomics and Department of Biological Chemistry, University of California, Irvine, School of Medicine, 2042 Hewitt Hall, Irvine, CA, 92697-3940, USA.
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5
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Tran RDH, Siemens M, Nguyen CHH, Ochs AR, Zaragoza MV, Grosberg A. The Effect of Cyclic Strain on Human Fibroblasts With Lamin A/C Mutations and Its Relation to Heart Disease. J Biomech Eng 2020; 142:061002. [PMID: 31233093 PMCID: PMC7104779 DOI: 10.1115/1.4044091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/12/2019] [Indexed: 12/26/2022]
Abstract
Although mutations in the Lamin A/C gene (LMNA) cause a variety of devastating diseases, the pathological mechanism is often unknown. Lamin A/C proteins play a crucial role in forming a meshwork under the nuclear membrane, providing the nucleus with mechanical integrity and interacting with other proteins for gene regulation. Most LMNA mutations result in heart diseases, including some types that primarily have heart disease as the main pathology. In this study, we used cells from patients with different LMNA mutations that primarily lead to heart disease. Indeed, it is a mystery why a mutation to the protein in every nucleus of the body manifests as a disease of primarily the heart in these patients. Here, we aimed to investigate if strains mimicking those within the myocardial environment are sufficient to cause differences in cells with and without the LMNA mutation. To test this, a stretcher device was used to induce cyclic strain upon cells, and viability/proliferation, cytoskeleton and extracellular matrix organization, and nuclear morphology were quantified. The properties of cells with Hutchinson-Gilford progeria syndrome (HGPS) were found to be significantly different from all other cell lines and were mostly in line with previous findings. However, the properties of cells from patients who primarily had heart diseases were not drastically different when compared to individuals without the LMNA mutation. Our results indicated that cyclic strain alone was insufficient to cause any significant differences that could explain the mechanisms that lead to heart diseases in these patients with LMNA mutations.
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Affiliation(s)
- Richard D. H. Tran
- Cardiovascular Modeling Laboratory, The Edwards Lifesciences Center for
Advanced Cardiovascular Technology, Department of Biomedical Engineering,
University of California, 2131 Engineering Hall Irvine, Irvine, CA
92697-2700 e-mail:
| | - Mark Siemens
- Cardiovascular Modeling Laboratory, The Edwards Lifesciences Center for
Advanced Cardiovascular Technology, Department of Biomedical Engineering,
University of California, 2131 Engineering Hall
Irvine, Irvine, CA 92697-2700
e-mail:
| | - Cecilia H. H. Nguyen
- Division of Genetics and Genomics, Department of Pediatrics, School of
Medicine, University of California, 2042 Hewitt Hall
Irvine, Irvine, CA 92697-3940
e-mail:
| | - Alexander R. Ochs
- Cardiovascular Modeling Laboratory, The Edwards Lifesciences Center for
Advanced Cardiovascular Technology, Department of Biomedical Engineering,
University of California, 2131 Engineering Hall
Irvine, Irvine, CA 92697-2700
e-mail:
| | - Michael V. Zaragoza
- Department of Pediatrics, Division of Genetics & Genomics, 2042
Hewitt Hall Irvine, Irvine, CA 92697-3940
- Department of Biological Chemistry, University of California, School of
Medicine, 2042 Hewitt Hall Irvine, Irvine, CA
92697-3940 e-mail:
| | - Anna Grosberg
- Cardiovascular Modeling Laboratory, The Edwards Lifesciences Center for
Advanced Cardiovascular Technology, Center for Complex Biological Systems,
Department of Biomedical Engineering, University of California,
2418 Engineering Hall Irvine, Irvine, CA
92697-2700
- Department of Chemical and Biomolecular Engineering, University of
California, 2418 Engineering Hall Irvine, Irvine, CA
92697-2700 e-mail:
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6
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Morris TA, Naik J, Fibben KS, Kong X, Kiyono T, Yokomori K, Grosberg A. Striated myocyte structural integrity: Automated analysis of sarcomeric z-discs. PLoS Comput Biol 2020; 16:e1007676. [PMID: 32130207 PMCID: PMC7075639 DOI: 10.1371/journal.pcbi.1007676] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/16/2020] [Accepted: 01/23/2020] [Indexed: 12/31/2022] Open
Abstract
As sarcomeres produce the force necessary for contraction, assessment of sarcomere order is paramount in evaluation of cardiac and skeletal myocytes. The uniaxial force produced by sarcomeres is ideally perpendicular to their z-lines, which couple parallel myofibrils and give cardiac and skeletal myocytes their distinct striated appearance. Accordingly, sarcomere structure is often evaluated by staining for z-line proteins such as α-actinin. However, due to limitations of current analysis methods, which require manual or semi-manual handling of images, the mechanism by which sarcomere and by extension z-line architecture can impact contraction and which characteristics of z-line architecture should be used to assess striated myocytes has not been fully explored. Challenges such as isolating z-lines from regions of off-target staining that occur along immature stress fibers and cell boundaries and choosing metrics to summarize overall z-line architecture have gone largely unaddressed in previous work. While an expert can qualitatively appraise tissues, these challenges leave researchers without robust, repeatable tools to assess z-line architecture across different labs and experiments. Additionally, the criteria used by experts to evaluate sarcomeric architecture have not been well-defined. We address these challenges by providing metrics that summarize different aspects of z-line architecture that correspond to expert tissue quality assessment and demonstrate their efficacy through an examination of engineered tissues and single cells. In doing so, we have elucidated a mechanism by which highly elongated cardiomyocytes become inefficient at producing force. Unlike previous manual or semi-manual methods, characterization of z-line architecture using the metrics discussed and implemented in this work can quantitatively evaluate engineered tissues and contribute to a robust understanding of the development and mechanics of striated muscles.
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Affiliation(s)
- Tessa Altair Morris
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
- Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, California, United States of America
| | - Jasmine Naik
- Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, California, United States of America
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, California, United States of America
| | - Kirby Sinclair Fibben
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
| | - Xiangduo Kong
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California, United States of America
| | - Tohru Kiyono
- Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tsukiji, Chuo-ku, Tokyo, Japan
| | - Kyoko Yokomori
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, California, United States of America
| | - Anna Grosberg
- Center for Complex Biological Systems, University of California, Irvine, Irvine, California, United States of America
- Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, California, United States of America
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, California, United States of America
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
- NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, California, United States of America
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7
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Ochs AR, Mehrabi M, Becker D, Asad MN, Zhao J, Zaragoza MV, Grosberg A. Databases to Efficiently Manage Medium Sized, Low Velocity, Multidimensional Data in Tissue Engineering. J Vis Exp 2019. [PMID: 31814616 DOI: 10.3791/60038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Science relies on increasingly complex data sets for progress, but common data management methods such as spreadsheet programs are inadequate for the growing scale and complexity of this information. While database management systems have the potential to rectify these issues, they are not commonly utilized outside of business and informatics fields. Yet, many research labs already generate "medium sized", low velocity, multi-dimensional data that could greatly benefit from implementing similar systems. In this article, we provide a conceptual overview explaining how databases function and the advantages they provide in tissue engineering applications. Structural fibroblast data from individuals with a lamin A/C mutation was used to illustrate examples within a specific experimental context. Examples include visualizing multidimensional data, linking tables in a relational database structure, mapping a semi-automated data pipeline to convert raw data into structured formats, and explaining the underlying syntax of a query. Outcomes from analyzing the data were used to create plots of various arrangements and significance was demonstrated in cell organization in aligned environments between the positive control of Hutchinson-Gilford progeria, a well-known laminopathy, and all other experimental groups. In comparison to spreadsheets, database methods were enormously time efficient, simple to use once set up, allowed for immediate access of original file locations, and increased data rigor. In response to the National Institutes of Health (NIH) emphasis on experimental rigor, it is likely that many scientific fields will eventually adopt databases as common practice due to their strong capability to effectively organize complex data.
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Affiliation(s)
- Alexander R Ochs
- Department of Biomedical Engineering, University of California, Irvine; The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine
| | - Mehrsa Mehrabi
- Department of Biomedical Engineering, University of California, Irvine; The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine
| | - Danielle Becker
- Department of Biomedical Engineering, University of California, Irvine; The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine
| | - Mira N Asad
- Department of Biomedical Engineering, University of California, Irvine; The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine
| | - Jing Zhao
- Department of Biomedical Engineering, University of California, Irvine; The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine
| | - Michael V Zaragoza
- Pediatrics-Genetics & Genomics Division-School of Medicine, University of California, Irvine; Biological Chemistry-School of Medicine, University of California, Irvine
| | - Anna Grosberg
- Department of Biomedical Engineering, University of California, Irvine; The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine; Department of Chemical and Biomolecular Engineering, University of California, Irvine; Center for Complex Biological Systems, University of California, Irvine; The NSF-Simons Center for Multiscale Cell Fate Research (CMCF), University of California, Irvine;
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8
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van Tienen FHJ, Lindsey PJ, Kamps MAF, Krapels IP, Ramaekers FCS, Brunner HG, van den Wijngaard A, Broers JLV. Assessment of fibroblast nuclear morphology aids interpretation of LMNA variants. Eur J Hum Genet 2018; 27:389-399. [PMID: 30420677 DOI: 10.1038/s41431-018-0294-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 10/12/2018] [Accepted: 10/16/2018] [Indexed: 01/26/2023] Open
Abstract
The phenotypic heterogeneity of Lamin A/C (LMNA) variants renders it difficult to classify them. As a consequence, many LMNA variants are classified as variant of unknown significance (VUS). A number of studies reported different types of visible nuclear abnormalities in LMNA-variant carriers, such as herniations, honeycomb-like structures and irregular Lamin staining. In this study, we used lamin A/C immunostaining and nuclear DAPI staining to assess the number and type of nuclear abnormalities in primary dermal fibroblast cultures of laminopathy patients and healthy controls. The total number of abnormal nuclei, which includes herniations, honeycomb-structures, and donut-like nuclei, was found to be the most discriminating parameter between laminopathy and control cell cultures. The percentage abnormal nuclei was subsequently scored in fibroblasts of 28 LMNA variant carriers, ranging from (likely) benign to (likely) pathogenic variant. Using this method, 27 out of 28 fibroblast cell cultures could be classified as either normal (n = 14) or laminopathy (n = 13) and no false positive results were obtained. The obtained specificity was 100% (CI 40-100%) and sensitivity 77% (46-95%). We conclude that assessing the percentage of abnormal nuclei is a quick and reliable method, which aids classification or confirms pathogenicity of identified LMNA variants causing formation of aberrant lamin A/C protein.
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Affiliation(s)
- Florence H J van Tienen
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands. .,GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.
| | - Patrick J Lindsey
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Miriam A F Kamps
- GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Ingrid P Krapels
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Frans C S Ramaekers
- GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Han G Brunner
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Arthur van den Wijngaard
- Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jos L V Broers
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, The Netherlands.,CARIM-School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
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9
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Williams JF, Mochrie SGJ, King MC. A versatile image analysis platform for three-dimensional nuclear reconstruction. Methods 2018; 157:15-27. [PMID: 30359725 DOI: 10.1016/j.ymeth.2018.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/09/2018] [Accepted: 10/15/2018] [Indexed: 12/22/2022] Open
Abstract
Nuclear morphology is indicative of cellular health in many contexts. In order to robustly and quantitatively measure nuclear size and shape, numerous experimental methods leveraging fluorescence microscopy have been developed. While these methods are useful for quantifying two-dimensional morphology, they often fail to accurately represent the three-dimensional structure of the nucleus, thus omitting important spatial and volumetric information. To address the need for a more accurate image analysis modality, we have developed a software platform that faithfully reconstructs membrane surfaces in three dimensions with sub-pixel resolution. Here, we showcase its broad applicability across species and nuclear scale, as well as provide information on how to employ this platform for diverse experimental systems.
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Affiliation(s)
- Jessica F Williams
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Simon G J Mochrie
- Department of Physics, Department of Applied Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
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