L8- Stem cells Flashcards
What are stem cells?
- Undifferentiated cells that can divide indefinitely and give rise to more specialised cells.
- When they divide they give rise to a differentiated cell and another stem cell (to self renew). Individual divisions may be symmetric but population is maintained.
What is a transit amplifier cell?
- The differentiated daughter cell produced from stem cell division.
- Often proliferative but limited
What are the different stem cell potentials?
Totipotent- all cell types
Pluripotent- all cell types except extra embryonic membranes
Multipotent- cell types within a tissue
Unipotent- one type of cell
What are the sources of adult stem cells?
Adult bone marrow- haematopoietic stem cells give rise to lymphocytes
Keratinocytes in the skin- give rise to epidemal cells of skin
Gut epithelium- give rise to all crypt and villus cells
Where are adult neural stem cells found?
2 mammalian forebrain regions:
- Subventricular zone- produces interneurons that migrate to olfactory bulbs
- Subgranular zone of hippocampus
What are the important properties of umbilical cord stem cells?
- Plasticity- potential to change into other cell types like nerve cells
- Homing- to travel to the site of tissue damage
- Engraftment- to unite with other tissues
What are embryonic stem cells?
Pluripotent- can develop into all tissue types
Can be indefinitely cultured in vitro
What is transgenesis?
Introducing a gene into an organism from another.
Embryonic stem cells in culture can be genetically manipulated like this by knocking in and out genes.
What are induced pluripotent stem cells?
When normal adult cells are reprogrammed to become stem cells by introducing and expressing transcription factors in culture - Oct3/4, Sox2, Klf4 etc
What are the pros and cons of iPSCs?
Very similar to ESC’s
Can make transgenic mice and all tissue types
Can be obtained from many sources
May cause cancer in transgenic mice
