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Lötstedt P. Derivation of continuum models from discrete models of mechanical forces in cell populations. J Math Biol 2021; 83:75. [PMID: 34878601 PMCID: PMC8654724 DOI: 10.1007/s00285-021-01697-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/23/2021] [Accepted: 11/16/2021] [Indexed: 11/14/2022]
Abstract
In certain discrete models of populations of biological cells, the mechanical forces between the cells are center based or vertex based on the microscopic level where each cell is individually represented. The cells are circular or spherical in a center based model and polygonal or polyhedral in a vertex based model. On a higher, macroscopic level, the time evolution of the density of the cells is described by partial differential equations (PDEs). We derive relations between the modelling on the micro and macro levels in one, two, and three dimensions by regarding the micro model as a discretization of a PDE for conservation of mass on the macro level. The forces in the micro model correspond on the macro level to a gradient of the pressure scaled by quantities depending on the cell geometry. The two levels of modelling are compared in numerical experiments in one and two dimensions.
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Affiliation(s)
- Per Lötstedt
- Division of Scientific Computing, Department of Information Technology, Uppsala University, 751 05, Uppsala, Sweden.
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Mathias S, Coulier A, Bouchnita A, Hellander A. Impact of Force Function Formulations on the Numerical Simulation of Centre-Based Models. Bull Math Biol 2020; 82:132. [PMID: 33025278 PMCID: PMC7538447 DOI: 10.1007/s11538-020-00810-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 09/21/2020] [Indexed: 12/17/2022]
Abstract
Centre-based or cell-centre models are a framework for the computational study of multicellular systems with widespread use in cancer modelling and computational developmental biology. At the core of these models are the numerical method used to update cell positions and the force functions that encode the pairwise mechanical interactions of cells. For the latter, there are multiple choices that could potentially affect both the biological behaviour captured, and the robustness and efficiency of simulation. For example, available open-source software implementations of centre-based models rely on different force functions for their default behaviour and it is not straightforward for a modeller to know if these are interchangeable. Our study addresses this problem and contributes to the understanding of the potential and limitations of three popular force functions from a numerical perspective. We show empirically that choosing the force parameters such that the relaxation time for two cells after cell division is consistent between different force functions results in good agreement of the population radius of a two-dimensional monolayer relaxing mechanically after intense cell proliferation. Furthermore, we report that numerical stability is not sufficient to prevent unphysical cell trajectories following cell division, and consequently, that too large time steps can cause geometrical differences at the population level.
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Affiliation(s)
- Sonja Mathias
- Department of Information Technology, Uppsala University, Uppsala, Sweden.
| | - Adrien Coulier
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Anass Bouchnita
- Department of Information Technology, Uppsala University, Uppsala, Sweden
- Ecole Centrale Casablanca, Bouskoura, Morocco
| | - Andreas Hellander
- Department of Information Technology, Uppsala University, Uppsala, Sweden
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Kashgari G, Meinecke L, Gordon W, Ruiz B, Yang J, Ma AL, Xie Y, Ho H, Plikus MV, Nie Q, Jester JV, Andersen B. Epithelial Migration and Non-adhesive Periderm Are Required for Digit Separation during Mammalian Development. Dev Cell 2020; 52:764-778.e4. [PMID: 32109382 DOI: 10.1016/j.devcel.2020.01.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/26/2019] [Accepted: 01/28/2020] [Indexed: 01/04/2023]
Abstract
The fusion of digits or toes, syndactyly, can be part of complex syndromes, including van der Woude syndrome. A subset of van der Woude cases is caused by dominant-negative mutations in the epithelial transcription factor Grainyhead like-3 (GRHL3), and Grhl3-/-mice have soft-tissue syndactyly. Although impaired interdigital cell death of mesenchymal cells causes syndactyly in multiple genetic mutants, Grhl3-/- embryos had normal interdigital cell death, suggesting alternative mechanisms for syndactyly. We found that in digit separation, the overlying epidermis forms a migrating interdigital epithelial tongue (IET) when the epithelium invaginates to separate the digits. Normally, the non-adhesive surface periderm allows the IET to bifurcate as the digits separate. In contrast, in Grhl3-/- embryos, the IET moves normally between the digits but fails to bifurcate because of abnormal adhesion of the periderm. Our study identifies epidermal developmental processes required for digit separation.
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Affiliation(s)
- Ghaidaa Kashgari
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Lina Meinecke
- Department of Mathematics, School of Physical Sciences, University of California, Irvine, Irvine, CA, USA; Department of Developmental & Cell Biology, School of the Biological Sciences, University of California, Irvine, Irvine, CA, USA
| | - William Gordon
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Bryan Ruiz
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Jady Yang
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Amy Lan Ma
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Yilu Xie
- The Gavin Herbert Eye Institute, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Hsiang Ho
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Maksim V Plikus
- Department of Developmental & Cell Biology, School of the Biological Sciences, University of California, Irvine, Irvine, CA, USA
| | - Qing Nie
- Department of Mathematics, School of Physical Sciences, University of California, Irvine, Irvine, CA, USA; Department of Developmental & Cell Biology, School of the Biological Sciences, University of California, Irvine, Irvine, CA, USA
| | - James V Jester
- The Gavin Herbert Eye Institute, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Bogi Andersen
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, Irvine, CA, USA; Department of Medicine, School of Medicine, University of California, Irvine, Irvine, CA, USA.
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