Renske de Veer (rdeveer)
Summary cell movements
Lecture 1.
Introduction.
Lecture 2. Cell movement in morphogenesis and wound healing.
➔ Morphogenesis more detailed discussed during journal club.
Wound healing
Tissue repair
1. Coagulation
- Cytokines, growth factors.
2. Inflammatory phase:
- Can last hours to days depending on type of wound etc.
- Neutrophils, macrophages (immune cells), bacteria and pathogens trying to get into the
wound.
- Will produce attractive environment for other cells to be recruited and repair tissue.
3. Repair phase
- Fibroblasts will come into wound, proliferate. Start remodelling. Become mayo-
fibroblasts
4. Remodelling
- Makes sure that excess in extracellular matrix and proliferation and scar tissue is
remodelled.
- Collagen produced, glycan produced.
Two receptors known to synergise and allow fibroblasts to move towards fibronectin.
- Integrin (a5b1)
- Syndecan-4 → proteoglycan. Transmembrane proteins. Very long protein of
carbohydrates.
o Activates Rho-A, Rac-GTP, RhoG, and Arf6
,Renske de Veer (rdeveer)
▪ RhoG and Arf6 are responsible for recycling of integrin. Integrin is anchor
of ECM, cells stick to it. But need to release when you want to move.
Cells endocytose integrins, put them in vesicles. Vesicles will be recycled
back to surface when necessary.
▪ RhoG internalizes integrin.
▪ Arf6 regulates recycling back to surface of integrin
Fibroblasts usually move as single cells.
Epithelial cells also need to migrate to close wounds.
Collective cell migration
- Occurs when multiple cells retain cell-cell contacts, coordinate their actin dynamics and
intracellular signalling and thereby form a structural and functional unit that translocates
across or through tissue. Collective cell movement contributes to cell and tissue
dynamics in morphogenesis, vascular sprouting, tissue repair and cancer invasion. The
underlying cellular and molecular mechanisms all depend upon the front-rear polarity of
collective adhesion and cytoskeletal dynamics, the integrity of cell-cell junctions and
often the structural modification of the tissue encountered.
, Renske de Veer (rdeveer)
How can one experimentally mimic and study cell migration mechanisms during wound healing?
- Mice can be used.
- In vitro: cell injury mechanism.
o Scratch assay: monolayer of cells. Make a scratch. How is scratch filled by cells?
o Stamp assay: Make stamp in middle, how will cell migrate in there.
o Cook cells: burn wound.
o Electrical wounding
o Laser: optical wounding
→Migration of “healthy” cell may be different from “damaged” or “injured” cells.
Vimentin intermediate filaments are the dominant cytoskeletal elements of repair cells at the wound
edge. Almost no F-actin.
→There is crosstalk present between different cytoskeletal components. Microtubule function is
required for extension of vimentin-rich lamellipodia by repair cells.
→Knockdown of vimentin prevented lamellipodial extension at the wound edge and slowed wound
closure.
→Disruption of vimentin function with WFA impaired extension of vimentin-rich lamellipodia by
repair cells at the wound edge and slowed wound healing.
Summary cell movements
Lecture 1.
Introduction.
Lecture 2. Cell movement in morphogenesis and wound healing.
➔ Morphogenesis more detailed discussed during journal club.
Wound healing
Tissue repair
1. Coagulation
- Cytokines, growth factors.
2. Inflammatory phase:
- Can last hours to days depending on type of wound etc.
- Neutrophils, macrophages (immune cells), bacteria and pathogens trying to get into the
wound.
- Will produce attractive environment for other cells to be recruited and repair tissue.
3. Repair phase
- Fibroblasts will come into wound, proliferate. Start remodelling. Become mayo-
fibroblasts
4. Remodelling
- Makes sure that excess in extracellular matrix and proliferation and scar tissue is
remodelled.
- Collagen produced, glycan produced.
Two receptors known to synergise and allow fibroblasts to move towards fibronectin.
- Integrin (a5b1)
- Syndecan-4 → proteoglycan. Transmembrane proteins. Very long protein of
carbohydrates.
o Activates Rho-A, Rac-GTP, RhoG, and Arf6
,Renske de Veer (rdeveer)
▪ RhoG and Arf6 are responsible for recycling of integrin. Integrin is anchor
of ECM, cells stick to it. But need to release when you want to move.
Cells endocytose integrins, put them in vesicles. Vesicles will be recycled
back to surface when necessary.
▪ RhoG internalizes integrin.
▪ Arf6 regulates recycling back to surface of integrin
Fibroblasts usually move as single cells.
Epithelial cells also need to migrate to close wounds.
Collective cell migration
- Occurs when multiple cells retain cell-cell contacts, coordinate their actin dynamics and
intracellular signalling and thereby form a structural and functional unit that translocates
across or through tissue. Collective cell movement contributes to cell and tissue
dynamics in morphogenesis, vascular sprouting, tissue repair and cancer invasion. The
underlying cellular and molecular mechanisms all depend upon the front-rear polarity of
collective adhesion and cytoskeletal dynamics, the integrity of cell-cell junctions and
often the structural modification of the tissue encountered.
, Renske de Veer (rdeveer)
How can one experimentally mimic and study cell migration mechanisms during wound healing?
- Mice can be used.
- In vitro: cell injury mechanism.
o Scratch assay: monolayer of cells. Make a scratch. How is scratch filled by cells?
o Stamp assay: Make stamp in middle, how will cell migrate in there.
o Cook cells: burn wound.
o Electrical wounding
o Laser: optical wounding
→Migration of “healthy” cell may be different from “damaged” or “injured” cells.
Vimentin intermediate filaments are the dominant cytoskeletal elements of repair cells at the wound
edge. Almost no F-actin.
→There is crosstalk present between different cytoskeletal components. Microtubule function is
required for extension of vimentin-rich lamellipodia by repair cells.
→Knockdown of vimentin prevented lamellipodial extension at the wound edge and slowed wound
closure.
→Disruption of vimentin function with WFA impaired extension of vimentin-rich lamellipodia by
repair cells at the wound edge and slowed wound healing.
