Regeneration Flashcards
Most animals have
some capacity to regenerate
Only very short lived animals have
no regenerative/wound response
Describe the spectrum of regeneration
- no cellular response to damage
- turnover of some tissues and organs
- regeneration of some tissues; organ homeostasis and repair
- regeneration of some tissues and organs
- regeneration of many tissues and organs
- whole body regeneration
Give a species that exhibits no cellular response to damage
C. elegans
Give a species that exhibits turnover of some tissues and organs
- D. melanogaster
- gut stem cells
Give some clades that exhibit regeneration of some tissues; organ homeostasis and repair
- African spiny mouse (60% of dorsal skin)
- mouse digit tip regeneration
- H. sapiens
Give some clades that exhibit regeneration of some tissues and organs
- Insects and Crustaceans
- lizards (tail loss)
- zebra fish
- Xenopus tadpoles
Give some clades that exhibit regeneration of many tissues and organs
- some flatworms
- some Cnidaria
- Ascidians
- Holuthurian
- Echinoderms
- Salamanders
Give some clades that exhibit WBR
- Planarians
- Hydra
- some annelids
- some colonial ascidians
List the major animal models of regeneration
- Hydrazoans
- Planaria
- Zebrafish
- Salamanders and Newts
- Xenopus
- Acoels
- Mouse and relatives
List the minor animal models of regeneration
- Annelids
- Insects
- Starfish
- Ascidians
- Sea Cucumbers
Why has regeneration remained poorly understood?
regenerators have life histories that aren’t accessible or convenient for classical genetics
Which tissues regenerate well?
- blood
- skin
- gut lining
Which tissues regenerate poorly?
- spinal cord
- cardiac muscles
- arms and legs
Give an example of regeneration
Newt limb regenerating tissues know precisely what is missing
Describe Hydra morphology
- mouth
- hypostome
- head
- tentacle
- body column
- bud
- basal disc
- foot
Describe Hydra regeneration
relies on lineage restricted populations of stem cells
Describe the possible products of a Hydra interstitial stem cell
- zymogen
- granular mucous
- spumous mucous
- male germline stem cells
- female germline stem cells
- sensory neurones
- ganglion neurones
- battery cells
- nematoblasts
battery cells
tentacles
nematoblasts
make 4 kinds of nematocysts
Describe the organs that the zebrafish can regenerate
- brain
- retina
- heart
- spinal cord
- liver
- pancreas
- kidney
- skin
- fin
Why might a zebrafish need to regenerate its brain?
stabbing/transection
Why might a zebrafish need to regenerate its retina?
light/heat
Why might a zebrafish need to regenerate its heart?
- resection
- cryoinjury
- genetic ablation
Why might a zebrafish need to regenerate its spinal cord?
stabbing/transection
Why might a zebrafish need to regenerate its liver?
- resection
- chemical
Why might a zebrafish need to regenerate its pancreas?
- chemical
Why might a zebrafish need to regenerate its skin?
light/heat
Why might a zebrafish need to regenerate its kidney?
- chemical
- genetic ablation
Why might a zebrafish need to regenerate its fin?
- resection
- cryoinjury
Describe zebrafish heart and fin regeneration
involves dedifferentiation of lineage restricted cells
Describe Xenopus tadpole and Axolotl limb regeneration
uses lineage restricted progenitors
Give some lineage-restricted progenitors in the Xenopus
- neural-plate
- notochord
- somites
Give some lineage-restricted progenitors in the Axolotl
- neural crest
- presomitic mesoderm
What do neural crest cells make?
Schwann cells
What do presomitic mesoderm cells make?
- muscle
- dermis
- cartilage
Describe the transdifferentiation of PECs to lens fibres during lens regeneration
- PECs dedifferentiate, depigmented and proliferate to create dedifferentiated intermediate cells
- redifferentiation and switch in cell phenotype through crystallin expression creates primary lens fibres
PECs
pigmented epithelial cells
Describe Planarian regeneration
- fuelled by neoblasts
neoblasts
planarian adult stem cells
What are Piwi positive stem cells
Marker of germline stem cells
Describe our approach to regeneration in mammals
- may require engineering using principles from lineage specific mechanisms (eye of newt)
- OR using pre-existing genetic pathways (newt within)
- or maybe both!
Describe the relationship between somatic and germline stem cells
- many highly regenerative organisms have somatic stem cells that express germ line stem cell genes
- may have a common evolutionary origin
Describe arthropod limb and muscle regeneration (through satellite cells) in Parhyale
- amputation/injury
- wound closure
- melanisation, blastema formation
- cell proliferation, morphogenesis and growth
- moulting, muscle formation
Describe vertebrate limb regeneration (through skeletal muscle satellite cell myogenesis) in the salamander
- amputation/injury
- wound healing through re-epithelialisation
- dedifferentiation and blastema formation
- cell proliferation
- differentiation, morphogenesis and growth
lineage committed stem cells may be
conserved
… stem cell systems underpin regeneration.
Different
