Adult Stem Cells Flashcards
What are adult stem cells?
They are lineage restricted (tissue specific) multi potent cells
What is immunomodulation?
Have the ability to modulate cells in the immune system through stem cells
How can adult stem cells be used for diagnosis and targets for treatments?
Targeting the stems cells that give origin to the cancers
What are the types of adult stem cells?
Types of stem cells
• HSCs - Hempatopoetic
• MSCs- Mesenchymal stem cells
• NSCs- neural stem cell
• Cord blood
• Cancer stem cells
What are adult stem cell properties
They undergo self renewal
Undergo symmetric and asymmetric division
Quiescence- may divide every two or three weeks
What is multipotent differentiation?
Has the ability to generate different differentiated cell types relevant to that tissue
Describe asymmetric division
Will become either stem cells or differentiated this is because distributions of contents of cells is different
Describe independent choice
After the first division either get a result of two stem cells, two differentiated or one each
What is the hay flick limit?
A term used to indicate a transition to cell senescence- decline in proliferation
How were haematopoietic stem cells classically defined by transplantation?
- X-irradiation halts blood cell production; mouse would die if no further treatment was given
- Inject bone marrow cells from healthy donor
- Mouse survives- the injected stem cells colonise its haematopoietic tissues and generate a steady supply of new blood cells
What does senescence result from?
Chromosome damage due to telomere shortening
What is telomerase?
An enzyme that maintains telomere length, by adding new DNA at each stem cell division
What are the proliferation and cell cycle markers?
• H3 Thymindine
• BrdU labelling index
• Cell cycle antigens e.g pH3, Ki67
What is cluster of differentiation (CD) antigens?
They are cell surface marker used to distinguish live cell lineages
How does fluorescence activated cell sorting work?
Antibodies attached to fluroescent cell sorting machine- will at if a cell is fluorescing or not
Can sort cells so can be collected for later analysis
What causes stem cells in their niche to remain as stem cells
the behaviour of environmental signals and intrinsic programmes that control stemness, proliferation and differentiation
What is the process of stem cells differentiating in intestinal stem cells?
Stem cells give rise to colony forming cells, which gradually push up as they move up the villus structure- they begin to differentiate as move up till reach end stage populations
How can lac Z gene be used to show that the villus comes from a single stem cell?
Single cell has been turned on to express the lac Z gene- which give rise to blue precipitate in cells as binds to substrates - within 60 days who population of cells made
What is the role of paneth cell niche?
They are directly adjacent to stem cells- which produces wnt3a- which causes them to maintain their stem cells state
What is lateral inhibition?
Refers to the capacity of excited neurons to reduce the activity of their neighbours
What stem cells can develop whole villus organoids?
What is LgR5?
LgR5 stem cells
LgR5 is a G-protein coupled receptor regulated by wnt
What 3 cels comprises the neurogenic lineage of subventricular zone?
SVZ astrocytes, transit amplifying cell, neuroblast
How can proliferating cells be identified?
Brdu Uptake
What factor can decrease proliferation in the brain?
Decease-
* Glutamate
* Stress
* Glucocorticoids
* Age/ disease
* Methamphetamine
* Opiate/ Heroin/ Morphine
* D3R antagonists
What factors can increase proliferation in the brain?
Increasing
* Serotonin
* Oestrogen
* Prolactin
* Wheel running
* Antidepressants
* Atypical antipsychotics
* D3 agonists
What markers identify HSCs
CD150+ and CD48-
How can HSCs be used in therapy
bone marrow transplants to restore HSC stores such as after chemo
or - use human HSC cells and treat with chemicals to cause differentiation and replace mutated cells
What types of trophic support can maintain tissue homeostasis
fibrosis, proliferation, apoptosis, chemotaxis, immunomodulation, angiogenesis
What are mesenchymal stem cells
express CD73,CD90 and CD105 and can differentiate into osteoblasts, adipocytes and chondroblasts.
separate population from HSCs as they do not express CD34
What cells express SCF
stroma cells which are adjacent to the endothelial cells
Where are CD150+/CD48- HSCs found in the bone marrow
adjacent to SCF and stromal cells
What are sinusoids in the bone marrow niche
specialised reticular network of venules that are concentrated in the endosteum
What niche to HSCs reside in
the bone marrow
What is the endosteum of the bone marrow
the interface between bone and bone marrow. provides an environment for signals such as cytokines and stem cells factor
