Topic 11: Adult Stem Cells Flashcards
describe the three properties of stem cell
- it itself is not terminaly differentiated
- it has the capacity for self renewal
- it has the ability to give rise to specialized cell types
what are the types potency of stem cells
- totipotent
- pluripotent
- multipotent
- unipotent
explain totipotent/omnipotent
can different into ANY type of cell like embryonic and extraembryonic
- produced after a egg becomes fertilized
explain pluripotent
the descendants of totipotent and can differentiate into almost any type of cell
explain mutipotent
can differentiate into different related cells (eg. blood cells)
explain unipotent
can only make itself over and over (skin cells)
where in the human body are stem cells usually found?
blood
skin
intestines
muscle
liver
ovaries and testies
what are the 2 mechanism for self renewal of stem cells
- divisional asymmetry
- environmental asymmetry
what is divisional asymmetry
intrinsic factor where one will stay a stem cella and the other will be specialized
what is environmental asymmetry
the environment affects the differentiation of each daughter cell
explain the features of intestinal cells
the crypts of the epithelium intestinal cells contain panneth cells at the very bottom (they are continuously differentiating)
one will stay a paneth while the other will start rapidly dividing and then at the top produce non dividing cells
what are the main types of differentiated epthial lining of the small insteine
- absorptive enterocytes (bush border): take up nutrients and secrete hydrolytic
- goblet cells: muscus
- enetrendrocrine: secrete hormone that signal neurons
- paneth cell: secrete substances to kill bacteria
explain clonal analysis can trace the progeny of stem cells
- all stem cells have a specific promoter that controls the release of GFP and inactive recombinase.
- When a stem cell differiates, it stops releasing GFP but still releases inactive recombinase.
- If you add tamoxifen it will active the recombinase and cleave out the blocking sequence that is stopping the the ubiquitous promoter for releasing Lac Z
- now the U-protomor will release Lac Z and now you know that cell was a stem cell
what are proneural and neurogenic genes?
proneural gene- they specify the cells that can become a neuroblast
neurogenic gene- the proneural gene that starts to become the neuroblast and stops the neighbouring cells from doing so
how do neurogenic gene cells inhibit the neighbouring cells
by notch signalling: the neurogenic cell has an inhibitory membrane bound signal called delta that interacts with the north receptor of the neighbouring cell
- the winner will have more deltas and becomes the neuroblast
what does the notch pathway do?
the 3 regulated proteolysis leads to the notch tail being migrated into the nucleus where it actives gene transcription
describe how a single mutipotent hematopoietic cells can give rise to differiented lympoid
the order goes
- multipotent hemapoietic stem cell
-multipotent hemapoietic progentitor
1 WAY
- common lymphoid precursor
- B cell and NK/T precursor
- NK and T cells
describe how a single mutipotent hematopoietic cells can give rise to differiented myeloid
the order goes
- multipotent hemapoietic stem cell
-multipotent hemapoietic progentitor
2nd WAY
- common myeloid precursor
- granulocyte & megakaryote progenitors
- g: macrophage
-g: monocyte
how can HSC be isolated?
fluorescence activated cell sorter
describe the theory of cancer stem cells
that some cancer cells may arise from a cell with stem cell like properties like self renewal and able to produce a differtinated progeny
