Green - Stem Cells Flashcards
Stem Cell
Undifferentiated, self renewing cells
What are three sources of Go cells that can proliferate?
Fibroblasts, Endothelial Cells, Liver Epithelial Cells
Totipotent
Can form complete organism, present in embryo
Pluripotent
Can form many tissue types, but not complete organism;
present in embryo
Multipotent
can form different types of cells within an organ, but not different organ or cell type
Present in adult
Ex: Hematapoeitic cells
Unipotent
Can form only one type of cell; present in adults
Explain stem cell division
One daughter cell remains stem cell, second divides and differentiates. These don’t always have to follow the same path; some will differentiate some will stay at certain points.
Transit Amplifying Cells
Rapidly dividing cells between stem cells and full differentiation; represent a point of no return
What determines the fate of a daughter stem cell?
Needs of the organism; driven by:
- Neighboring cell signals
- Microenvironment of stem cells–niche
Hematopoietic Stem Cells
Form red blood cells, platelets, and immune cells
What produces the niche in humans?
Liver in late fetal development; bone marrow in adults
Where are intestinal stem cells found? How do they differentiate?
Crypt
Divide and differentiate as they move up the villus
What is the stem cell of the crypt?
Lgr5+
What is the key regulator of stem cells in the intestines?
Wnt protein secreted by niche cells
What are the two sources of clinical stem cells?
Embryonic Stem Cells (ES) and Iduced Pluripotent (iPS) Stem Cells
What is the source of ES Cells?
What type of stem cells are these?
Inner cell mass in blastocyst
Pluripotent
iPS Cells
What type of stem cells are these?
Reprogrammed adult cells
Pluripotent
How are ES cells maintained in culture?
Conditioned medium that contains growth factors, taken from irradiated fibroblast cells–can’t divide
What are the inhibitory growth factors for ES cells?
What occurs if these are removed
LIF for mouse
bFBF for human cells
ES cells form multicellular aggregates that resemble early embryos–embryoid bodies
What regulates pluripotency of ES cells?
Transcriptional Factors
Oct4, Sox2, Nanog
Each binds to own promoter and to other promoters–can activate or repress genes
How can you form iPS cells from adult cells?
Add correct transcriptional factors
Oct4
Sox2
Klf4
c-Myc
Somatic Nuclear Transfer
Transfer of nucleus from adult cell into unfertilized egg
What are two examples of somatic cell nuclear transfer?
GFP mice
Cloned animals (Dolly)
What are some medical applications of iPS cells?
Hematopoietic stem cell transplantation
Testing drugs for individual implementation
Therapeutic cloning (healing a patient with their own stem cells)
