collective cell migration
- wound healing, morphogenesis, bone remodelling…
- two or more cells
- cells physically and functionally connected via proteins
- polarity of the population
- modification of the environment to create a path
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| Term | Definition |
|---|---|
collective cell migration | - wound healing, morphogenesis, bone remodelling…
- two or more cells
- cells physically and functionally connected via proteins
- polarity of the population
- modification of the environment to create a path |
zebrafish > lateral line primordium (LLP) | - 100 cells
- from the head to the tail
- 3000 μm, 42h
- rosettes (20 cells) deposition |
chemical gradient | A difference in concentration (or chemical potential) of a molecule or ion across a membrane or space.
|
what does a chemical gradient do? | energetic drivers—they store free energy that can be converted into work |
examples of a chemical gradient | High K⁺ inside a cell, low K⁺ outside
Proton gradient across mitochondria
Diffusion of a neurotransmitter |
mechanical gradient | A difference in physical force, pressure, tension, shear, or deformation across a system. |
examples of mechanical gradient | Membrane tension on mechanosensitive channels (e.g., Piezo1, TREK/TRAAK)
Osmotic pressure differences causing swelling
Tissue stretch, compression, shear flow on endothelial cells |
what does mechanical gradient do? | change the energy landscape of proteins or membranes, commonly altering gating of mechanosensitive channels |
lattice models in modelling collective migration | H(t) = Htension + Hshape + Hmigration-polarity |
lattice models are ____ | - explicit and detailed description of cell functions
- analysis of rearrangement
- parameters far from experimental observations |
phase-field models | measure:
- force balance (ie static mechanical equilibrium)
- tissue mechanics
- cell-cell and cell-substrate friction and active stress |
cell-cell interactions via a free energy functional | F = Fch + Farea + Fcell-cell |
examples of phase field models | - shape-based anisotropic active stress
- velocity alignment
- collective motion |
vertex models | - polygones vertices
- rearrangement inducing appearance and disappearance of
vertices and specific rules implementation |
voronoi models | - polygones centers
- dynamic network |
energy function | - areas and perimeters
- polar forces at vertices or centers |
voronoi models uses | - confluent tissues with no space between cells
- epithelial populations
- role of cell geometry and topological rearrangement
- no internal dissipation nor anisotropic active stress |
particles models | - cell as one or two circular particles
- central interparticle potential
- attraction and repulsion
- active polar force to account for cell motility |
uses of particles models | - no details for cell shape and polarity
- epithelial and mesenchymal cells
- tissue stress tensor |
continuum models | multicellular scale |
populations described by fields | - velocity, polarity, density, …
- free energy of quiescent media
- density andpolarity dynamics
- force balance
- consitutive law
- boundary conditions |
hybrid continuum model | links discrete cell-level representations with continuum fields (like density, stress, or chemical concentrations) to capture both individual and tissue-scale dynamics in a single framework. |
intra-synchronization | active deformations & adhesion forces |
inter-synchronization | coordination between cells in order to be as
efficient as possible |
ellipse geometry | rows and columns of cells |
regulatized heaviside functions (geometry) | - cell network
- active and quiescent cells
- extracellular matrix (ECM) |
geometry measrures the ____ of each cell | frontal and rear edge |
constitutive laws of quiescent cells and ECM | - generalized viscoelastic Maxwell model
- no active strain |
intra-synchronization between active strain and adhesion forces | - frontal protrusion and rear adhesion
- frontal adhesion and rear contraction |
strain gradient signal is an example of | inter-synchronization |
strain gradient signal | - all the cell are active
- the active deformation decreases from the stern
to the bow of the population (gradient) |
worm-like migration is an example of | inter-synchronization |
worm-like migration | - travelling wave with pulse signal
- successive activation and deactivation the cells
- repetitive wave |
tsunami-like migration is an example of | inter-synchronization |
tsunami-like migration | - tsunami-like migration
- a cell only migrates if a space is created around it
- permanent activation of cells |
random-signal inter-synchronization | - all the cells are active
- migration out of phase
- each cell has its own migration period |
most efficient modes of inter-synchronization | worm-like and tsunami-like migrations |
least efficient modes of inter-synchronization | strain gradient and random migration |
what is the most efficient cells in inter-synchronization? | leader cells (propulsion system) |
where are the highest stresses in inter-synchronization? | central cells and during the least efficient modes of migration |
what are not stand-alone factors? | inter-synchronization and randomness |