In vitro Stem Cells Flashcards
List the three types of stem cells and ther purpose.
- in vivo - generate cells during development
- in vivo - maintain structures in the adult
- in vitro (test tube) - repair tissues or model disease/development
4
List some limitations associated with embryonic stem cell research.
- Not around anymore in the adult
- Immune rejection to established ES cell lines
- Cell lines more likely to accumulate mutations
- Moral/religious issues
What did John Gurdon show in 1962 with an adult intestinal frog cell?
That the cell could support the development of a new frog when it replaced the oocyte nucleus.
What did Gurdon’s discovery mean?
That the epigenetic marks that restrict fates in the DNA of adults can be reversed.
3 steps
Outline the experiment conducted by Gurdon that earned him the Nobel Prize in Physiology or Medicine in 2012?
- Eliminated the nucleus of a frog egg cell
- Replaced it with the nucleus from a specialised cell taken from a tadpole.
- The modified egg developed into a normal tadpole
What breakthrough did Shinya Yamanaka make in 2006 in regards to in vitro stem cells?
Showed that the introduction of 4 stem cell genes into adult fibroblasts could reprogram them back into immature stem cells.
What are the reprogrammed stem cells discovered by Yamanaka called?
Induced pluripotent stem cells (iPS cells)
List the four reprogramming factors used by Yamanaka.
- Klf4
- Sox2
- Oct4
- Myc
True or false: iPS cells have the same potency as ES cells.
True
What type of cells can iPS cells develop into?
Muscle, neuron, skin
What is a stem cell?
A cell that retains its ability to divide and re-create itself while also having the ability to generate progeny capable of specializing into a more differentiated cell type.
What potency are embryonic stem cells?
Pluripotent
What are multipotent stem cells?
Stem cells that generate cell types with restricted specificity for the tissue in which they reside.
What is typically the potency of adult stem cells?
Multipotent
What are unipotent stem cells?
Stem cells that generate only one cell type.
From what two major sources are pluripotent embryonic cells derived in the lab?
- ICM of early blastocysts
- Undifferentiated PGCs
What are the three core transcription factors that maintain the pluripotency of ESCs?
Oct4, Sox2, Nanog
How do Sox2 and Oct4 induce pluripotency?
Activate Nanog and other transcription factors that establish pluripotency and block differentiation.
How does c-Myc induce pluripotency?
Opens up chromatin and makes genes accessible to Sox2, Oct4 and Nanog
How does Klf4 induce pluripotency?
Prevents cell death
What are the current four major medical uses for iPSCs?
- Making patient-specific iPSCs for studying disease pathology
- Combining gene therapy with patient-specific iPSCs to treat disease
- Cell transplants using patient-derived progenitor cells
- Using differentiated cells derived from patient-derived iPSCs for screening drugs.
5
List the most complex structures that have been created using iPSCs.
Optic cup
Mini-guts
Kidney tissues
Liver buds
Brain regions
What is the typical size of an organoid?
Size of a pea
How long can organoids be maintained in culture for?
For more than a year.
True or false: Organoids mimic embryonic organogenesis.
True
