1
|
Badvaram I, Camley BA. Physical limits to membrane curvature sensing by a single protein. Phys Rev E 2023; 108:064407. [PMID: 38243534 DOI: 10.1103/physreve.108.064407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 09/11/2023] [Indexed: 01/21/2024]
Abstract
Membrane curvature sensing is essential for a diverse range of biological processes. Recent experiments have revealed that a single nanometer-sized septin protein has different binding rates to membrane-coated glass beads of 1-µm and 3-µm diameters, even though the septin is orders of magnitude smaller than the beads. This sensing ability is especially surprising since curvature-sensing proteins must deal with persistent thermal fluctuations of the membrane, leading to discrepancies between the bead's curvature and the local membrane curvature sensed instantaneously by a protein. Using continuum models of fluctuating membranes, we investigate whether it is feasible for a protein acting as a perfect observer of the membrane to sense micron-scale curvature either by measuring local membrane curvature or by using bilayer lipid densities as a proxy. To do this, we develop algorithms to simulate lipid density and membrane shape fluctuations. We derive physical limits to the sensing efficacy of a protein in terms of protein size, membrane thickness, membrane bending modulus, membrane-substrate adhesion strength, and bead size. To explain the experimental protein-bead association rates, we develop two classes of predictive models: (i) for proteins that maximally associate to a preferred curvature and (ii) for proteins with enhanced association rates above a threshold curvature. We find that the experimentally observed sensing efficacy is close to the theoretical sensing limits imposed on a septin-sized protein. Protein-membrane association rates may depend on the curvature of the bead, but the strength of this dependence is limited by the fluctuations in membrane height and density.
Collapse
Affiliation(s)
- Indrajit Badvaram
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Brian A Camley
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| |
Collapse
|
2
|
Lavrentev FV, Shilovskikh VV, Alabusheva VS, Yurova VY, Nikitina AA, Ulasevich SA, Skorb EV. Diffusion-Limited Processes in Hydrogels with Chosen Applications from Drug Delivery to Electronic Components. Molecules 2023; 28:5931. [PMID: 37570901 PMCID: PMC10421015 DOI: 10.3390/molecules28155931] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Diffusion is one of the key nature processes which plays an important role in respiration, digestion, and nutrient transport in cells. In this regard, the present article aims to review various diffusion approaches used to fabricate different functional materials based on hydrogels, unique examples of materials that control diffusion. They have found applications in fields such as drug encapsulation and delivery, nutrient delivery in agriculture, developing materials for regenerative medicine, and creating stimuli-responsive materials in soft robotics and microrobotics. In addition, mechanisms of release and drug diffusion kinetics as key tools for material design are discussed.
Collapse
Affiliation(s)
- Filipp V. Lavrentev
- Infochemistry Scientific Center, ITMO University, 191002 Saint Petersburg, Russia; (V.S.A.); (V.Y.Y.); (A.A.N.); (S.A.U.)
| | - Vladimir V. Shilovskikh
- Laboratory of Polymer and Composite Materials “SmartTextiles”, IRC–X-ray Coherent Optics, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia;
| | - Varvara S. Alabusheva
- Infochemistry Scientific Center, ITMO University, 191002 Saint Petersburg, Russia; (V.S.A.); (V.Y.Y.); (A.A.N.); (S.A.U.)
| | - Veronika Yu. Yurova
- Infochemistry Scientific Center, ITMO University, 191002 Saint Petersburg, Russia; (V.S.A.); (V.Y.Y.); (A.A.N.); (S.A.U.)
| | - Anna A. Nikitina
- Infochemistry Scientific Center, ITMO University, 191002 Saint Petersburg, Russia; (V.S.A.); (V.Y.Y.); (A.A.N.); (S.A.U.)
| | - Sviatlana A. Ulasevich
- Infochemistry Scientific Center, ITMO University, 191002 Saint Petersburg, Russia; (V.S.A.); (V.Y.Y.); (A.A.N.); (S.A.U.)
| | - Ekaterina V. Skorb
- Infochemistry Scientific Center, ITMO University, 191002 Saint Petersburg, Russia; (V.S.A.); (V.Y.Y.); (A.A.N.); (S.A.U.)
| |
Collapse
|
3
|
Kaiyrbekov K, Endresen K, Sullivan K, Zheng Z, Chen Y, Serra F, Camley BA. Migration and division in cell monolayers on substrates with topological defects. Proc Natl Acad Sci U S A 2023; 120:e2301197120. [PMID: 37463218 PMCID: PMC10372565 DOI: 10.1073/pnas.2301197120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/27/2023] [Indexed: 07/20/2023] Open
Abstract
Collective movement and organization of cell monolayers are important for wound healing and tissue development. Recent experiments highlighted the importance of liquid crystal order within these layers, suggesting that +1 topological defects have a role in organizing tissue morphogenesis. We study fibroblast organization, motion, and proliferation on a substrate with micron-sized ridges that induce +1 and -1 topological defects using simulation and experiment. We model cells as self-propelled deformable ellipses that interact via a Gay-Berne potential. Unlike earlier work on other cell types, we see that density variation near defects is not explained by collective migration. We propose instead that fibroblasts have different division rates depending on their area and aspect ratio. This model captures key features of our previous experiments: the alignment quality worsens at high cell density and, at the center of the +1 defects, cells can adopt either highly anisotropic or primarily isotropic morphologies. Experiments performed with different ridge heights confirm a prediction of this model: Suppressing migration across ridges promotes higher cell density at the +1 defect. Our work enables a mechanism for tissue patterning using topological defects without relying on cell migration.
Collapse
Affiliation(s)
- Kurmanbek Kaiyrbekov
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
| | - Kirsten Endresen
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
| | - Kyle Sullivan
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
| | - Zhaofei Zheng
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
| | - Yun Chen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD21218
| | - Francesca Serra
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense5230, Denmark
| | - Brian A. Camley
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, MD21218
- Department of Biophysics, Johns Hopkins University, Baltimore, MD21218
| |
Collapse
|
4
|
Nampoothiri S. Preferential localization of a single spot in reaction-diffusion systems on non-spherical surfaces. SOFT MATTER 2023; 19:1977-1986. [PMID: 36847585 DOI: 10.1039/d2sm01287a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The present work systematically examines the effect of breaking the rotational symmetry of a surface on the spot positioning in reaction-diffusion (RD) systems. In particular, we study analytically and numerically the steady-state positioning of a single spot in RD systems on a prolate and an oblate ellipsoid. We adapt perturbative techniques to perform a linear stability analysis of the RD system on both ellipsoids. Furthermore, the spot positionings in the steady states of non-linear RD equations are obtained numerically on both ellipsoids. Our analysis suggests that preferential spot positioning can be observed on non-spherical surfaces. The present work may provide useful insights into the role of cell geometry on various symmetry-breaking mechanisms in cellular processes.
Collapse
Affiliation(s)
- Sankaran Nampoothiri
- Department of Physics, Gandhi Institute of Technology and Management (GITAM) University, Bengaluru, India.
- Dipartimento di Fisica e Astronomia G. Galilei - DFA, Sezione INFN, Universit di Padova, Via Marzolo 8, 35131 Padova, PD, Italy
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Hesaraghatta Hobli, Bengaluru North, 560089, India
| |
Collapse
|
5
|
Nwogbaga I, Camley BA. Coupling cell shape and velocity leads to oscillation and circling in keratocyte galvanotaxis. Biophys J 2023; 122:130-142. [PMID: 36397670 PMCID: PMC9822803 DOI: 10.1016/j.bpj.2022.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 10/03/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
During wound healing, fish keratocyte cells undergo galvanotaxis where they follow a wound-induced electric field. In addition to their stereotypical persistent motion, keratocytes can develop circular motion without a field or oscillate while crawling in the field direction. We developed a coarse-grained phenomenological model that captures these keratocyte behaviors. We fit this model to experimental data on keratocyte response to an electric field being turned on. A critical element of our model is a tendency for cells to turn toward their long axis, arising from a coupling between cell shape and velocity, which gives rise to oscillatory and circular motion. Galvanotaxis is influenced not only by the field-dependent responses, but also cell speed and cell shape relaxation rate. When the cell reacts to an electric field being turned on, our model predicts that stiff, slow cells react slowly but follow the signal reliably. Cells that polarize and align to the field at a faster rate react more quickly and follow the signal more reliably. When cells are exposed to a field that switches direction rapidly, cells follow the average of field directions, while if the field is switched more slowly, cells follow a "staircase" pattern. Our study indicated that a simple phenomenological model coupling cell speed and shape is sufficient to reproduce a broad variety of different keratocyte behaviors, ranging from circling to oscillation to galvanotactic response, by only varying a few parameters.
Collapse
Affiliation(s)
- Ifunanya Nwogbaga
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland
| | - Brian A Camley
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland; William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, Maryland.
| |
Collapse
|
6
|
Cusseddu D, Madzvamuse A. Numerical investigations of the bulk-surface wave pinning model. Math Biosci 2022; 354:108925. [PMID: 36397641 DOI: 10.1016/j.mbs.2022.108925] [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: 05/25/2022] [Revised: 10/12/2022] [Accepted: 10/15/2022] [Indexed: 11/15/2022]
Abstract
The bulk-surface wave pinning model is a reaction-diffusion system for studying cell polarisation. It is constituted by a surface reaction-diffusion equation, coupled to a bulk diffusion equation with a non-linear boundary condition. Cell polarisation arises as the surface component develops specific patterns. Since proteins diffuse much faster in the cell interior than on the membrane, in the literature, the bulk component is often assumed to be spatially homogeneous. Therefore, the model can be reduced to a single surface equation. However, in real applications a spatially non-uniform bulk component might be an important player to take into account. In this paper, we study, through numerical computations, the role of the bulk component and, more specifically, how different bulk diffusion rates might affect the polarisation response. We find that the bulk component is indeed a key factor in determining the surface polarisation response. Moreover, for certain geometries, it is the spatial heterogeneity of the bulk component that triggers the polarisation response, which might not be possible in a reduced model. Understanding how polarisation depends on bulk diffusivity might be crucial when studying models of migrating cells, which are naturally subject to domain deformation.
Collapse
Affiliation(s)
- Davide Cusseddu
- Grupo de Física-Matematica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisboa, 1749-016, Portugal; Department of Mathematics, School of Mathematical and Physical Sciences, University of Sussex, Sussex House, Falmer, Brighton, BN1 9RH, United Kingdom.
| | - Anotida Madzvamuse
- Faculty of Science, Vancouver Campus, Mathematics Department, 121 - 1984 Mathematics Road, Vancouver, B.C., Canada V6T 1Z2; Department of Mathematics, School of Mathematical and Physical Sciences, University of Sussex, Sussex House, Falmer, Brighton, BN1 9RH, United Kingdom.
| |
Collapse
|
7
|
Zadeh P, Camley BA. Picking winners in cell-cell collisions: Wetting, speed, and contact. Phys Rev E 2022; 106:054413. [PMID: 36559372 DOI: 10.1103/physreve.106.054413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/27/2022] [Indexed: 06/17/2023]
Abstract
Groups of eukaryotic cells can coordinate their crawling motion to follow cues more effectively, stay together, or invade new areas. This collective cell migration depends on cell-cell interactions, which are often studied by colliding pairs of cells together. Can the outcome of these collisions be predicted? Recent experiments on trains of colliding epithelial cells suggest that cells with a smaller contact angle to the surface or larger speeds are more likely to maintain their direction ("win") upon collision. When should we expect shape or speed to correlate with the outcome of a collision? To investigate this question, we build a model for two-cell collisions within the phase field framework, which allows for cell shape changes. We can reproduce the observation that cells with high speed and small contact angles are more likely to win with two different assumptions for how cells interact: (1) velocity aligning, in which we hypothesize that cells sense their own velocity and align to it over a finite timescale, and (2) front-front contact repolarization, where cells polarize away from cell-cell contact, akin to contact inhibition of locomotion. Surprisingly, though we simulate collisions between cells with widely varying properties, in each case, the probability of a cell winning is completely captured by a single summary variable: its relative speed (in the velocity-aligning model) or its relative contact angle (in the contact repolarization model). Both models are currently consistent with reported experimental results, but they can be distinguished by varying cell contact angle and speed through orthogonal perturbations.
Collapse
Affiliation(s)
- Pedrom Zadeh
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, Maryland 21210, USA
| | - Brian A Camley
- William H. Miller III Department of Physics & Astronomy, Johns Hopkins University, Baltimore, Maryland 21210, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
| |
Collapse
|