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Mao Y, Wickström SA. Mechanical state transitions in the regulation of tissue form and function. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00719-x. [PMID: 38600372 DOI: 10.1038/s41580-024-00719-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2024] [Indexed: 04/12/2024]
Abstract
From embryonic development, postnatal growth and adult homeostasis to reparative and disease states, cells and tissues undergo constant changes in genome activity, cell fate, proliferation, movement, metabolism and growth. Importantly, these biological state transitions are coupled to changes in the mechanical and material properties of cells and tissues, termed mechanical state transitions. These mechanical states share features with physical states of matter, liquids and solids. Tissues can switch between mechanical states by changing behavioural dynamics or connectivity between cells. Conversely, these changes in tissue mechanical properties are known to control cell and tissue function, most importantly the ability of cells to move or tissues to deform. Thus, tissue mechanical state transitions are implicated in transmitting information across biological length and time scales, especially during processes of early development, wound healing and diseases such as cancer. This Review will focus on the biological basis of tissue-scale mechanical state transitions, how they emerge from molecular and cellular interactions, and their roles in organismal development, homeostasis, regeneration and disease.
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Affiliation(s)
- Yanlan Mao
- Laboratory for Molecular Cell Biology, University College London, London, UK.
- Institute for the Physics of Living Systems, University College London, London, UK.
| | - Sara A Wickström
- Department of Cell and Tissue Dynamics, Max Planck Institute for Molecular Biomedicine, Münster, Germany.
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Helsinki Institute of Life Science, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland.
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2
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York AR, Sherwood CC, Manger PR, Kaas JH, Mota B, Herculano-Houzel S. Folding of the cerebellar cortex is clade-specific in form but universal in degree. J Comp Neurol 2024; 532:e25616. [PMID: 38634526 DOI: 10.1002/cne.25616] [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: 05/17/2023] [Revised: 02/01/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Like the cerebralcortex, the surface of the cerebellum is repeatedly folded. Unlike the cerebralcortex, however, cerebellar folds are much thinner and more numerous; repeatthemselves largely along a single direction, forming accordion-like folds transverseto the mid-sagittal plane; and occur in all but the smallest cerebella. We haveshown previously that while the location of folds in mammalian cerebral cortex isclade-specific, the overall degree of folding strictly follows a universalpower law relating cortical thickness and the exposed and total surface areas predictedfrom the minimization of the effective free energy of an expanding, self-avoidingsurface of a certain thickness. Here we show that this scaling law extends tothe folding of the mid-sagittal sections of the cerebellum of 53 speciesbelonging to six mammalian clades. Simultaneously, we show that each clade hasa previously unsuspected distinctive spatial pattern of folding evident at themid-sagittal surface of the cerebellum. We note, however, that the mammaliancerebellum folds as a multi-fractal object, because of the difference betweenthe outside-in development of the cerebellar cortex around a preexisting coreof already connected white matter, compared to the inside-out development ofthe cerebral cortex with a white matter volume that develops as the cerebralcortex itself gains neurons. We conclude that repeated folding, one of the mostrecognizable features of biology, can arise simply from the interplay betweenthe universal applicability of the physics of self-organization and biological,phylogenetical clade-specific contingency, without the need for invokingselective pressures in evolution.
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Affiliation(s)
- Annaleigh R York
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
| | - Chet C Sherwood
- Department of Anthropology, The George Washington University, Washington, District of Columbia, USA
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witswatersrand, Johannesburg, South Africa
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
| | - Bruno Mota
- Institute of Physics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
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3
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Cook AG, Bishop TV, Crowe HR, Stevens DN, Reine L, Joyner AL, Lawton AK. Cell division angle predicts the level of tissue mechanics that tune the amount of cerebellar folding. Development 2024; 151:dev202184. [PMID: 38251865 PMCID: PMC10911135 DOI: 10.1242/dev.202184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/10/2024] [Indexed: 01/23/2024]
Abstract
Modeling has led to proposals that the amount of neural tissue folding is set by the level of differential expansion between tissue layers and that the wavelength is set by the thickness of the outer layer. Here, we used inbred mouse strains with distinct amounts of cerebellar folding to investigate these predictions. We identified a distinct critical period during which the folding amount diverges between the two strains. In this period, regional changes in the level of differential expansion between the external granule layer (EGL) and underlying core correlate with the folding amount in each strain. Additionally, the thickness of the EGL varies regionally during the critical period alongside corresponding changes in wavelength. The number of SHH-expressing Purkinje cells predicts the folding amount, but the proliferation rate in the EGL is the same between the strains. However, regional changes in the cell division angle within the EGL predicts both the tangential expansion and the thickness of the EGL. Cell division angle is likely a tunable mechanism whereby both the level of differential expansion along the perimeter and the thickness of the EGL are regionally tuned to set the amount and wavelength of folding.
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Affiliation(s)
- Amber G. Cook
- Department of Biological Sciences, Mississippi State University, MS 39762, USA
| | - Taylor V. Bishop
- Department of Biological Sciences, Mississippi State University, MS 39762, USA
| | - Hannah R. Crowe
- Department of Biological Sciences, Mississippi State University, MS 39762, USA
| | - Daniel N. Stevens
- Developmental Biology Program, Sloan Kettering Institute, NY 10065, USA
| | - Lauren Reine
- Department of Biological Sciences, Mississippi State University, MS 39762, USA
| | | | - Andrew K. Lawton
- Department of Biological Sciences, Mississippi State University, MS 39762, USA
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Sanghrajka RM, Koche R, Medrano H, El Nagar S, Stephen DN, Lao Z, Bayin NS, Ge K, Joyner AL. KMT2D suppresses Sonic hedgehog-driven medulloblastoma progression and metastasis. iScience 2023; 26:107831. [PMID: 37822508 PMCID: PMC10562805 DOI: 10.1016/j.isci.2023.107831] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 03/29/2023] [Accepted: 09/01/2023] [Indexed: 10/13/2023] Open
Abstract
The major cause of treatment failure and mortality among medulloblastoma patients is metastasis intracranially or along the spinal cord. The molecular mechanisms driving tumor metastasis in Sonic hedgehog-driven medulloblastoma (SHH-MB) patients, however, remain largely unknown. In this study we define a tumor suppressive role of KMT2D (MLL2), a gene frequently mutated in the most metastatic β-subtype. Strikingly, genetic mouse models of SHH-MB demonstrate that heterozygous loss of Kmt2d in conjunction with activation of the SHH pathway causes highly penetrant disease with decreased survival, increased hindbrain invasion and spinal cord metastasis. Loss of Kmt2d attenuates neural differentiation and shifts the transcriptional/chromatin landscape of primary and metastatic tumors toward a decrease in differentiation genes and tumor suppressors and an increase in genes/pathways implicated in advanced stage cancer and metastasis (TGFβ, Notch, Atoh1, Sox2, and Myc). Thus, secondary heterozygous KMT2D mutations likely have prognostic value for identifying SHH-MB patients prone to develop metastasis.
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Affiliation(s)
- Reeti Mayur Sanghrajka
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Biochemistry, Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Richard Koche
- Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Hector Medrano
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Salsabiel El Nagar
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Daniel N. Stephen
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zhimin Lao
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - N. Sumru Bayin
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kai Ge
- Adipocyte Biology and Gene Regulation Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD, USA
| | - Alexandra L. Joyner
- Developmental Biology Program, Sloan Kettering Institute of Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Biochemistry, Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
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5
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Heuer K, Traut N, de Sousa AA, Valk SL, Clavel J, Toro R. Diversity and evolution of cerebellar folding in mammals. eLife 2023; 12:e85907. [PMID: 37737580 PMCID: PMC10617990 DOI: 10.7554/elife.85907] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 09/22/2023] [Indexed: 09/23/2023] Open
Abstract
The process of brain folding is thought to play an important role in the development and organisation of the cerebrum and the cerebellum. The study of cerebellar folding is challenging due to the small size and abundance of its folia. In consequence, little is known about its anatomical diversity and evolution. We constituted an open collection of histological data from 56 mammalian species and manually segmented the cerebrum and the cerebellum. We developed methods to measure the geometry of cerebellar folia and to estimate the thickness of the molecular layer. We used phylogenetic comparative methods to study the diversity and evolution of cerebellar folding and its relationship with the anatomy of the cerebrum. Our results show that the evolution of cerebellar and cerebral anatomy follows a stabilising selection process. We observed two groups of phenotypes changing concertedly through evolution: a group of 'diverse' phenotypes - varying over several orders of magnitude together with body size, and a group of 'stable' phenotypes varying over less than 1 order of magnitude across species. Our analyses confirmed the strong correlation between cerebral and cerebellar volumes across species, and showed in addition that large cerebella are disproportionately more folded than smaller ones. Compared with the extreme variations in cerebellar surface area, folial anatomy and molecular layer thickness varied only slightly, showing a much smaller increase in the larger cerebella. We discuss how these findings could provide new insights into the diversity and evolution of cerebellar folding, the mechanisms of cerebellar and cerebral folding, and their potential influence on the organisation of the brain across species.
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Affiliation(s)
- Katja Heuer
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et ThéoriqueParisFrance
| | - Nicolas Traut
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et ThéoriqueParisFrance
| | | | - Sofie Louise Valk
- Otto Hahn Group Cognitive Neurogenetics, Max Planck Institute for Human Cognitive and Brain SciencesLeipzigGermany
- Institute of Neuroscience and Medicine, Brain & Behaviour (INM-7), Research Centre Jülich, FZ JülichJülichGermany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University DüsseldorfDüsseldorfGermany
| | - Julien Clavel
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNAVilleurbanneFrance
| | - Roberto Toro
- Institut Pasteur, Université Paris Cité, Unité de Neuroanatomie Appliquée et ThéoriqueParisFrance
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Cook AG, Bishop TV, Crowe HR, Stevens D, Reine L, Joyner AL, Lawton AK. Cell division angle regulates the tissue mechanics and tunes the amount of cerebellar folding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.21.549165. [PMID: 37503300 PMCID: PMC10370211 DOI: 10.1101/2023.07.21.549165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Modeling has proposed that the amount of neural tissue folding is set by the level of differential-expansion between tissue layers and that the wavelength is set by the thickness of the outer layer. Here we used inbred mouse strains with distinct amounts of cerebellar folding to investigate these predictions. We identified a critical period where the folding amount diverges between the strains. In this period, regional changes in the level of differential-expansion between the external granule layer (EGL) and underlying core correlate with the folding amount in each strain. Additionally, the thickness of the EGL is regionally adjusted during the critical period alongside corresponding changes in wavelength. While the number of SHH-expressing Purkinje cells predicts the folding amount, the proliferation rate in the EGL is the same between the strains. However, regional changes in the cell division angle within the EGL predicts both the tangential-expansion and thickness of the EGL. Cell division angle is likely a tunable mechanism whereby both the level of differential-expansion and thickness of the EGL are regionally tuned to set the amount and wavelength of folding.
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Affiliation(s)
| | | | | | - Daniel Stevens
- Developmental Biology Program, Sloan Kettering Institute, United States
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Sutlive J, Seyyedhosseinzadeh H, Ao Z, Xiu H, Choudhury S, Gou K, Guo F, Chen Z. Mechanics of morphogenesis in neural development: In vivo, in vitro, and in silico. BRAIN MULTIPHYSICS 2023. [DOI: 10.1016/j.brain.2022.100062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Joyner AL, Bayin NS. Cerebellum lineage allocation, morphogenesis and repair: impact of interplay amongst cells. Development 2022; 149:dev185587. [PMID: 36172987 PMCID: PMC9641654 DOI: 10.1242/dev.185587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The cerebellum has a simple cytoarchitecture consisting of a folded cortex with three cell layers that surrounds a nuclear structure housing the output neurons. The excitatory neurons are generated from a unique progenitor zone, the rhombic lip, whereas the inhibitory neurons and astrocytes are generated from the ventricular zone. The growth phase of the cerebellum is driven by lineage-restricted progenitor populations derived from each zone. Research during the past decade has uncovered the importance of cell-to-cell communication between the lineages through largely unknown signaling mechanisms for regulating the scaling of cell numbers and cell plasticity during mouse development and following injury in the neonatal (P0-P14) cerebellum. This Review focuses on how the interplay between cell types is key to morphogenesis, production of robust neural circuits and replenishment of cells after injury, and ends with a discussion of the implications of the greater complexity of the human cerebellar progenitor zones for development and disease.
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Affiliation(s)
- Alexandra L. Joyner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
- Biochemistry Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY 10065, USA
| | - N. Sumru Bayin
- Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge University, Cambridge CB2 1NQ, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3DY, UK
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Biomechanical changes in myopic sclera correlate with underlying changes in microstructure. Exp Eye Res 2022; 224:109165. [PMID: 35810771 DOI: 10.1016/j.exer.2022.109165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 11/21/2022]
Abstract
Myopia alters the microstructural and biomechanical properties of the posterior sclera, which is characterized as a layered structure with potentially different inter-layer collagen fibril characteristics. Scanning acoustic microscopy (SAM) has been used to investigate how the micron-scale bulk mechanical properties of the posterior sclera are affected by myopia. Other investigators have employed second harmonic generation (SHG) imaging to characterize the collagen microstructure of tissues. In the present study, SAM and SHG imaging were used to investigate the existence of biomechanically-distinct scleral layers and identify relationships between mechanical properties and tissue microstructure in myopic guinea pig (GP) eyes. Diffusers were worn over the right eyes of six, 1-week-old GPs for one week to induce unilateral form-deprivation myopia. GPs were euthanized, enucleated, and eyes were cryosectioned. Twelve-micron-thick adjacent vertical cryosections were scanned with SAM or SHG. SAM maps of bulk modulus, mass density, and acoustic attenuation were estimated. A fiber-extraction algorithm applied to SHG images estimated collagen fiber length, width, straightness, alignment, and number density. Results revealed that the posterior sclera may exhibit biomechanically distinct layers that are affected differently in myopia. Specifically, a layered structure was observed in the mechanical-parameter maps of control eyes that was less apparent in myopic eyes. Collagen fibers in myopic eyes had smaller diameters and were more aligned. Myopia-associated biomechanical changes were most significant in the outermost and innermost scleral layers. SAM-measured mechanical parameters were correlated with collagen fiber microstructure, particularly fiber length, alignment, and number density, which may imply the biomechanical parameters estimated from SAM measurements are related to tissue microstructure. Interestingly, some changes were greatest in more-peripheral regions, suggesting interventions to strengthen the sclera may be effective away from the optic nerve and efficacy may be achieved best when intervention is applied to the outermost layer.
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Wang Y, Cui H, Esworthy T, Mei D, Wang Y, Zhang LG. Emerging 4D Printing Strategies for Next-Generation Tissue Regeneration and Medical Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109198. [PMID: 34951494 DOI: 10.1002/adma.202109198] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/17/2021] [Indexed: 06/14/2023]
Abstract
The rapid development of 3D printing has led to considerable progress in the field of biomedical engineering. Notably, 4D printing provides a potential strategy to achieve a time-dependent physical change within tissue scaffolds or replicate the dynamic biological behaviors of native tissues for smart tissue regeneration and the fabrication of medical devices. The fabricated stimulus-responsive structures can offer dynamic, reprogrammable deformation or actuation to mimic complex physical, biochemical, and mechanical processes of native tissues. Although there is notable progress made in the development of the 4D printing approach for various biomedical applications, its more broad-scale adoption for clinical use and tissue engineering purposes is complicated by a notable limitation of printable smart materials and the simplistic nature of achievable responses possible with current sources of stimulation. In this review, the recent progress made in the field of 4D printing by discussing the various printing mechanisms that are achieved with great emphasis on smart ink mechanisms of 4D actuation, construct structural design, and printing technologies, is highlighted. Recent 4D printing studies which focus on the applications of tissue/organ regeneration and medical devices are then summarized. Finally, the current challenges and future perspectives of 4D printing are also discussed.
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Affiliation(s)
- Yue Wang
- State Key Laboratory of Fluid Power and Mechatronics Systems, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, School of Mechanical Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Haitao Cui
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Timothy Esworthy
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Deqing Mei
- State Key Laboratory of Fluid Power and Mechatronics Systems, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, School of Mechanical Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Yancheng Wang
- State Key Laboratory of Fluid Power and Mechatronics Systems, Zhejiang University, Hangzhou, 310027, China
- Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, School of Mechanical Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lijie Grace Zhang
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC, 20052, USA
- Department of Electrical and Computer Engineering, The George Washington University, Washington, DC, 20052, USA
- Department of Biomedical Engineering, The George Washington University, Washington, DC, 20052, USA
- Department of Medicine, The George Washington University, Washington, DC, 20052, USA
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Luciano M, Versaevel M, Vercruysse E, Procès A, Kalukula Y, Remson A, Deridoux A, Gabriele S. Appreciating the role of cell shape changes in the mechanobiology of epithelial tissues. BIOPHYSICS REVIEWS 2022; 3:011305. [PMID: 38505223 PMCID: PMC10903419 DOI: 10.1063/5.0074317] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 02/23/2022] [Indexed: 03/21/2024]
Abstract
The wide range of epithelial cell shapes reveals the complexity and diversity of the intracellular mechanisms that serve to construct their morphology and regulate their functions. Using mechanosensitive steps, epithelial cells can sense a variety of different mechanochemical stimuli and adapt their behavior by reshaping their morphology. These changes of cell shape rely on a structural reorganization in space and time that generates modifications of the tensional state and activates biochemical cascades. Recent studies have started to unveil how the cell shape maintenance is involved in mechanical homeostatic tasks to sustain epithelial tissue folding, identity, and self-renewal. Here, we review relevant works that integrated mechanobiology to elucidate some of the core principles of how cell shape may be conveyed into spatial information to guide collective processes such as epithelial morphogenesis. Among many other parameters, we show that the regulation of the cell shape can be understood as the result of the interplay between two counteracting mechanisms: actomyosin contractility and intercellular adhesions, and that both do not act independently but are functionally integrated to operate on molecular, cellular, and tissue scales. We highlight the role of cadherin-based adhesions in force-sensing and mechanotransduction, and we report recent developments that exploit physics of liquid crystals to connect cell shape changes to orientational order in cell aggregates. Finally, we emphasize that the further intermingling of different disciplines to develop new mechanobiology assays will lead the way toward a unified picture of the contribution of cell shape to the pathophysiological behavior of epithelial tissues.
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Affiliation(s)
- Marine Luciano
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Marie Versaevel
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Eléonore Vercruysse
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Anthony Procès
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Yohalie Kalukula
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Alexandre Remson
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Amandine Deridoux
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
| | - Sylvain Gabriele
- University of Mons, Interfaces and Complex Fluids Laboratory, Mechanobiology and Biomaterials Group, Research Institute for Biosciences, CIRMAP, 20 Place du Parc, B-7000 Mons, Belgium
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Bayin NS, Mizrak D, Stephen DN, Lao Z, Sims PA, Joyner AL. Injury-induced ASCL1 expression orchestrates a transitory cell state required for repair of the neonatal cerebellum. SCIENCE ADVANCES 2021; 7:eabj1598. [PMID: 34878841 PMCID: PMC8654303 DOI: 10.1126/sciadv.abj1598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 10/20/2021] [Indexed: 05/23/2023]
Abstract
To understand repair processes, it is critical to identify the molecular foundations underlying progenitor diversity and plasticity. Upon injury to the neonatal cerebellum, a normally gliogenic nestin-expressing progenitor (NEP) in the Bergmann glia layer (BgL) undergoes adaptive reprograming to restore granule cell production. However, the cellular states and genes regulating the NEP fate switch are unknown. Using single-cell RNA sequencing and fate mapping, we defined molecular subtypes of NEPs and their lineages under homeostasis and repair. NEPs contain two major subtypes: Hopx+ astrogliogenic and Ascl1+ neurogenic NEPs that are further subdivided based on their location, lineage, and differentiation status. Upon injury, an Ascl1+ transitory cellular state arises from Hopx+ BgL-NEPs. Furthermore, mutational analysis revealed that induction of Ascl1 is required for adaptive reprogramming by orchestrating a glial-to-neural switch in vivo following injury. Thus, we provide molecular and cellular insights into context-dependent progenitor plasticity and repair mechanisms in the brain.
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Affiliation(s)
- N. Sumru Bayin
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Dogukan Mizrak
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Daniel N. Stephen
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Zhimin Lao
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Peter A. Sims
- Department of Systems Biology, Columbia University, New York, NY, USA
- Department of Biochemistry and Biophysics, Columbia University, New York, NY, USA
| | - Alexandra L. Joyner
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
- Biochemistry, Cell and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
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13
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Zhu Y, Deng S, Zhao X, Xia G, Zhao R, Chan HF. Deciphering and engineering tissue folding: A mechanical perspective. Acta Biomater 2021; 134:32-42. [PMID: 34325076 DOI: 10.1016/j.actbio.2021.07.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 07/16/2021] [Accepted: 07/21/2021] [Indexed: 12/19/2022]
Abstract
The folding of tissues/organs into complex shapes is a common phenomenon that occurs in organisms such as animals and plants, and is both structurally and functionally important. Deciphering the process of tissue folding and applying this knowledge to engineer folded systems would significantly advance the field of tissue engineering. Although early studies focused on investigating the biochemical signaling events that occur during the folding process, the physical or mechanical aspects of the process have received increasing attention in recent years. In this review, we will summarize recent findings on the mechanical aspects of folding and introduce strategies by which folding can be controlled in vitro. Emphasis will be placed on the folding events triggered by mechanical effects at the cellular and tissue levels and on the different cell- and biomaterial-based approaches used to recapitulate folding. Finally, we will provide a perspective on the development of engineering tissue folding toward preclinical and clinical translation. STATEMENT OF SIGNIFICANCE: Tissue folding is a common phenomenon in a variety of organisms including human, and has been shown to serve important structural and functional roles. Understanding how folding forms and applying the concept in tissue engineering would represent an advance of the research field. Recently, the physical or mechanical aspect of tissue folding has gained increasing attention. In this review, we will cover recent findings of the mechanical aspect of folding mechanisms, and introduce strategies to control the folding process in vitro. We will also provide a perspective on the future development of the field towards preclinical and clinical translation of various bio fabrication technologies.
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Affiliation(s)
- Yanlun Zhu
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China; Key Laboratory for Regenerative Medicine of the Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Shuai Deng
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China; Key Laboratory for Regenerative Medicine of the Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Xiaoyu Zhao
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China; Key Laboratory for Regenerative Medicine of the Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China; Shun Hing Institute of Advanced Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Guanggai Xia
- Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai 200233, China
| | - Ruike Zhao
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Hon Fai Chan
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China; Key Laboratory for Regenerative Medicine of the Ministry of Education of China, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China; Shun Hing Institute of Advanced Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China; Hong Kong Branch of CAS Center for Excellence in Animal Evolution and Genetics, Hong Kong SAR, China.
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14
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Reddy NC, Majidi SP, Kong L, Nemera M, Ferguson CJ, Moore M, Goncalves TM, Liu HK, Fitzpatrick JAJ, Zhao G, Yamada T, Bonni A, Gabel HW. CHARGE syndrome protein CHD7 regulates epigenomic activation of enhancers in granule cell precursors and gyrification of the cerebellum. Nat Commun 2021; 12:5702. [PMID: 34588434 PMCID: PMC8481233 DOI: 10.1038/s41467-021-25846-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 09/01/2021] [Indexed: 12/16/2022] Open
Abstract
Regulation of chromatin plays fundamental roles in the development of the brain. Haploinsufficiency of the chromatin remodeling enzyme CHD7 causes CHARGE syndrome, a genetic disorder that affects the development of the cerebellum. However, how CHD7 controls chromatin states in the cerebellum remains incompletely understood. Using conditional knockout of CHD7 in granule cell precursors in the mouse cerebellum, we find that CHD7 robustly promotes chromatin accessibility, active histone modifications, and RNA polymerase recruitment at enhancers. In vivo profiling of genome architecture reveals that CHD7 concordantly regulates epigenomic modifications associated with enhancer activation and gene expression of topologically-interacting genes. Genome and gene ontology studies show that CHD7-regulated enhancers are associated with genes that control brain tissue morphogenesis. Accordingly, conditional knockout of CHD7 triggers a striking phenotype of cerebellar polymicrogyria, which we have also found in a case of CHARGE syndrome. Finally, we uncover a CHD7-dependent switch in the preferred orientation of granule cell precursor division in the developing cerebellum, providing a potential cellular basis for the cerebellar polymicrogyria phenotype upon loss of CHD7. Collectively, our findings define epigenomic regulation by CHD7 in granule cell precursors and identify abnormal cerebellar patterning upon CHD7 depletion, with potential implications for our understanding of CHARGE syndrome. CHARGE syndrome that affects cerebellar development can be caused by haploinsufficiency of the chromatin remodeling enzyme CHD7; however the precise role of CHD7 remains unknown. Here the authors show CHD7 promotes chromatin accessibility and enhancer activity in granule cell precursors and regulates morphogenesis of the cerebellar cortex, where loss of CHD7 triggers cerebellar polymicrogyria.
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Affiliation(s)
- Naveen C Reddy
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Shahriyar P Majidi
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.,MD-PhD Program, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Lingchun Kong
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Mati Nemera
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Cole J Ferguson
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Michael Moore
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tassia M Goncalves
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hai-Kun Liu
- Division of Molecular Neurogenetics, DKFZ-ZMBH Alliance, German Cancer Research Center Im Neunheimer Feld 280, 69120, Heidelberg, Germany
| | - James A J Fitzpatrick
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.,Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Guoyan Zhao
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Tomoko Yamada
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Department of Neurobiology, Northwestern University, Evanston, IL, 60201, USA
| | - Azad Bonni
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.
| | - Harrison W Gabel
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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15
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Momin A, Bahrampour S, Min HK, Chen X, Wang X, Sun Y, Huang X. Channeling Force in the Brain: Mechanosensitive Ion Channels Choreograph Mechanics and Malignancies. Trends Pharmacol Sci 2021; 42:367-384. [PMID: 33752907 DOI: 10.1016/j.tips.2021.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/15/2021] [Accepted: 02/26/2021] [Indexed: 12/15/2022]
Abstract
Force is everywhere. Through cell-intrinsic activities and interactions with the microenvironment, cells generate, transmit, and sense mechanical forces, such as compression, tension, and shear stress. These forces shape the mechanical properties of cells and tissues. Akin to how balanced biochemical signaling safeguards physiological processes, a mechanical optimum is required for homeostasis. The brain constructs a mechanical optimum from its cellular and extracellular constituents. However, in brain cancer, the mechanical properties are disrupted: tumor and nontumoral cells experience dysregulated solid and fluid stress, while tumor tissue develops altered stiffness. Mechanosensitive (MS) ion channels perceive mechanical cues to govern ion flux and cellular signaling. In this review, we describe the mechanical properties of the brain in healthy and cancer states and illustrate MS ion channels as sensors of mechanical cues to regulate malignant growth. Targeting MS ion channels offers disease insights at the interface of cancer, neuroscience, and mechanobiology to reveal therapeutic opportunities in brain tumors.
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Affiliation(s)
- Ali Momin
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ONT, M5S 3E1, Canada.
| | - Shahrzad Bahrampour
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, 171 77, Sweden
| | - Hyun-Kee Min
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ONT, M5S 3E1, Canada
| | - Xin Chen
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada
| | - Xian Wang
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada
| | - Yu Sun
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ONT, M5S 3G8, Canada
| | - Xi Huang
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ONT, M5S 3E1, Canada.
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16
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Abstract
Brain structures change shape dramatically during development. Elucidating the mechanisms of morphogenesis provides insights relevant to understanding brain function in health and disease. The tension-based morphogenesis (TBM) hypothesis posits that mechanical tension along axons, dendrites, and glial processes contributes to many aspects of central nervous system morphogenesis. Since TBM was proposed in 1997, extensive evidence supports a role for tension in diverse cellular phenomena, but tension’s role in cortical folding has been controversial. An extensively revised version of the TBM model for cerebral cortex addresses limitations of the original model, incorporates new features, and can be tested by many experimental approaches. For cerebellar cortex, a revised model accounts for many aspects of its development and adult architecture. Mechanical tension along the length of axons, dendrites, and glial processes has been proposed as a major contributor to morphogenesis throughout the nervous system [D. C. Van Essen, Nature 385, 313–318 (1997)]. Tension-based morphogenesis (TBM) is a conceptually simple and general hypothesis based on physical forces that help shape all living things. Moreover, if each axon and dendrite strive to shorten while preserving connectivity, aggregate wiring length would remain low. TBM can explain key aspects of how the cerebral and cerebellar cortices remain thin, expand in surface area, and acquire their distinctive folds. This article reviews progress since 1997 relevant to TBM and other candidate morphogenetic mechanisms. At a cellular level, studies of diverse cell types in vitro and in vivo demonstrate that tension plays a major role in many developmental events. At a tissue level, I propose a differential expansion sandwich plus (DES+) revision to the original TBM model for cerebral cortical expansion and folding. It invokes tangential tension and “sulcal zipping” forces along the outer cortical margin as well as tension in the white matter core, together competing against radially biased tension in the cortical gray matter. Evidence for and against the DES+ model is discussed, and experiments are proposed to address key tenets of the DES+ model. For cerebellar cortex, a cerebellar multilayer sandwich (CMS) model is proposed that can account for many distinctive features, including its unique, accordion-like folding in the adult, and experiments are proposed to address its specific tenets.
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17
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Groden M, Weigand M, Triesch J, Jedlicka P, Cuntz H. A Model of Brain Folding Based on Strong Local and Weak Long-Range Connectivity Requirements. Cereb Cortex 2019; 30:2434-2451. [DOI: 10.1093/cercor/bhz249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 12/21/2022] Open
Abstract
Abstract
Throughout the animal kingdom, the structure of the central nervous system varies widely from distributed ganglia in worms to compact brains with varying degrees of folding in mammals. The differences in structure may indicate a fundamentally different circuit organization. However, the folded brain most likely is a direct result of mechanical forces when considering that a larger surface area of cortex packs into the restricted volume provided by the skull. Here, we introduce a computational model that instead of modeling mechanical forces relies on dimension reduction methods to place neurons according to specific connectivity requirements. For a simplified connectivity with strong local and weak long-range connections, our model predicts a transition from separate ganglia through smooth brain structures to heavily folded brains as the number of cortical columns increases. The model reproduces experimentally determined relationships between metrics of cortical folding and its pathological phenotypes in lissencephaly, polymicrogyria, microcephaly, autism, and schizophrenia. This suggests that mechanical forces that are known to lead to cortical folding may synergistically contribute to arrangements that reduce wiring. Our model provides a unified conceptual understanding of gyrification linking cellular connectivity and macroscopic structures in large-scale neural network models of the brain.
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Affiliation(s)
- Moritz Groden
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main D-60528, Germany
- Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main D-60438, Germany
- ICAR3R—Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University Giessen, Giessen D-35390, Germany
| | - Marvin Weigand
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main D-60528, Germany
- Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main D-60438, Germany
- Faculty of Biological Sciences, Goethe University, Frankfurt am Main D-60438, Germany
| | - Jochen Triesch
- Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main D-60438, Germany
- Faculty of Physics, Goethe University, Frankfurt am Main D-60438, Germany
- Faculty of Computer Science and Mathematics, Goethe University, Frankfurt am Main D-60438, Germany
| | - Peter Jedlicka
- Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main D-60438, Germany
- ICAR3R—Interdisciplinary Centre for 3Rs in Animal Research, Justus Liebig University Giessen, Giessen D-35390, Germany
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University, Frankfurt am Main D-60528, Germany
| | - Hermann Cuntz
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main D-60528, Germany
- Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main D-60438, Germany
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18
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Hoang QV, Rohrbach D, McFadden SA, Mamou J. Regional changes in the elastic properties of myopic Guinea pig sclera. Exp Eye Res 2019; 186:107739. [PMID: 31330141 PMCID: PMC6712578 DOI: 10.1016/j.exer.2019.107739] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 07/11/2019] [Accepted: 07/18/2019] [Indexed: 11/17/2022]
Abstract
Biomechanical changes in the sclera likely underlie the excessive eye elongation of axial myopia. We studied the biomechanical characteristics of myopic sclera at the microscopic level using scanning acoustic microscopy (SAM) with 7-μm in-plane resolution. Guinea pigs underwent form-deprivation (FD) in one eye from 4 to 12 days of age to induce myopia, and 12-μm-thick scleral cryosections were scanned using a custom-made SAM. Two-dimensional maps of the bulk modulus (K) and mass density (ρ) were derived from the SAM data using a frequency-domain approach. We assessed the effect on K and ρ exerted by: 1) level of induced myopia, 2) region (superior, inferior, nasal or temporal) and 3) eccentricity from the nerve using univariate and multivariate regression analyses. Induced myopia ranged between -3D and -9.3D (Mean intraocular difference of -6.2 ± 1.7D, N = 11). K decreased by 0.036 GPa for every 1.0 D increase in induced myopia across vertical sections (p < 0.001). Among induced myopia right eyes, K values in the inherently more myopic superior region were 0.088 GPa less than the inferior region (p = 0.002) and K in the proximal nasal region containing the central axis were 0.10 GPa less than temporal K (p = 0.036). K also increased 0.12 GPa for every 1 mm increase in superior vertical distance (p < 0.001), an effect that was blunted after 1 week of FD. Overall, trends for ρ were less apparent than for K. ρ values increased by 20.7 mg/cm3 for every 1.00 D increase in induced myopia across horizontal sections (p < 0.001), and were greatest in the region containing the central posterior pole. ρ values in the inherently more myopic superior region were 13.1 mg/cm3 greater than that found in inferior regions among control eyes (p = 0.002), and increased by 11.2 mg/cm3 for every 1 mm increase in vertical distance (p = 0.001). This peripheral increase in ρ was blunted after 1 week of FD. Scleral material properties vary depending on the location in the sclera and the level of induced myopia. Bulk modulus was most reduced in the most myopic regions (both induced myopia and inherent regional myopia), and suggests that FD causes microscopic local decreases in sclera stiffness, while scleral mass density was most increased in the most myopic regions.
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Affiliation(s)
- Quan V Hoang
- Department of Ophthalmology, Columbia University Medical Center, New York, NY, 10032, USA; Singapore Eye Research Institute, Singapore National Eye Centre, Duke-NUS Medical School, Singapore.
| | - Daniel Rohrbach
- Lizzi Center for Biomedical Engineering, Riverside Research, New York, NY, 10038, USA
| | - Sally A McFadden
- Vision Sciences, School of Psychology, Faculty of Science and Hunter Medical Research Institute, University of Newcastle, NSW, Australia
| | - Jonathan Mamou
- Lizzi Center for Biomedical Engineering, Riverside Research, New York, NY, 10038, USA
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