Stem Cells Flashcards
stem cell
remain in undifferentiated state
when divide, make stem cell and new cell committed to differentiation
-divide asymmetrically
undergo unlimited # cell divisions
HAVE POTENCY
potency
potential to differentiate into many cell types
totipotent
make any cell type in the body and extra embryonic tissues
pluripotent
can make any fetal of adult cell but NOT placenta
-genes expressed: OCt4, Sox2, Nanog, Lin28
multipotent
can make different adult tissues
unipotent
can only give rise to one type of differentiated cells
environmental asymmetry
daughter cells produced by division of stem cell are initially the same, but environmental influences direct one daughter cell to differentiate
divisional asymmetry
internal factors direct one of daughter cells to follow path of differentiation
transit amplifying cells
-divide frequently (limited number of divisions)
progeny of transit amplfying cells can differentiate due to environmental causes
stiff
strong adhesion between ECM and cell-> TF factors YAP and TAZ active-> bone cell
soft
weak adhesion (off-> fat cell)
somatic stem cells
multipotent can replenish cell types in specific tissue but not ANY tissue
skin
express high levels of Beta1 integrin
differentiation skin cells express keratin-10
frequently dividing cells marked BrdU incorporation
gut
stem cells found in crypts
wnt makes secretory cells
hematopoietic stem cells
capable of indefinite self renewal
gives rise to MPP-> multiple cells but limited
express KIT, SCA1, and low leels of CD34 and FLK2 on surface
HSCs must remain in contact w stromal cells
in the bone marrow to retain their stem-ness
stem cells express Kit receptors-> initate cascade within stem cell to allow to continue being stem cell
–stem cell divides interaction w stromal cell is lost-> kit no longer active and cell is committed to differentiated state
