Lect 9 Stem Cells Flashcards
What is a stem cell?
Characteristics?
- A primitive cell that can differentiate into multiple, functional cell types or self-renew
- Characteristics:
- Not terminally differentiated
- Can divide without limit (telomerase)
- Undergo slow division
What is the difference in adult stem cells compared to embryonic?
They are tissue specific
* Potency *
What is totipotency? Type of stem cell?
What is pluripotentcy? Type of stem cell?
What is multipotentcy? Type of stem cell?
-
Totipotentcy: give rise all cells of an organism (embryonic and extraembryonic tissues)
- Zygote
-
Pluripotency: give rise to all cells of the embryo and adult tissues
- Blastocyst/ICM
-
Multipotentcy: give rise to different cell types of 3 germ cell layers (Endoderm, Ectoderm, Mesoderm)
- Adult stem cell
Founder Stem Cells
Each tissue has fixed number of founder cell poulations with fixed number of divisions that early on determine what?
They are controlled by what?
Proportion/size of body parts and define the size of large final structures
Short range signaling
* Transit Amplifying Cells *
What are they?
Where do they originate from?
Programmed to have what?
Frequently dividing cells
Cell with SC characteristics –> differentiated cell (leave basal layer and incorporate into layers above)
Limited number of divisions –> finite
* Maintenance of Stem Cells *
What percentage of daughter cells remain stem cells after division?
This is accomplished by what two types of asymmetry?
- 50% of daughter cells are stem cells
- Divisional Asymmetry
- One with SC characteristics; One with factors giving ability to differentiate
- Environmental Asymmetry
- Two identical cells, environment can influence 1 cell to differentiate
Immortal Strand Hypothesis
What is preserved from generation to generation?
What happens to the second cell?
Original strand of DNA preserved in stem cells from generation to generation
Second cell gets newly synthesized strand and becomes differentiated
Stem Cell Hierarchy
Embryonic and Adult stem cells are what type of potentcy?
Stem cells differentiate in stages, what do these stages involve?
Pluripotent and Multipotent
Multiple factors producing epigenetic markers in cell’s DNA, restricting DNA expression and the type of cell that the stem cell will differentiate into
* Embryonic Stem Cells *
What are they derived from?
What would happen if put back into blastocyst?
What can they give rise to consequentially?
Blastocyst/ICM
Integrate well with embryo and develop
Teratomas (any of the three germ layers)
Production of Different Cell Types
Adding Retinoic Acid?
Adding M-CSF?
Adding FGF?
Adipocyte, Neuron, Muscle
Macrophage
Astrocytes, Oligodendrocytes
Genes in Pluripotent Cells
TFs (Nanog, Oct4, Sox2, FoxD3) are essential for what?
Establishment and maintenance of pluripotent stem cells in embryo
Hematopoietic and Stromal (Mesenchymal) Stem Cells
Where do they both originate from?
What do HSCs and MSCs differentiate into?
Bone marrow
HSC: Blood components (Platelets, WBCs, RBCs)
MSC: Connective tissues, other tissues
Cord Blood
Why is this significant?
They are undifferentiated and have potential to treat many diseases
Central Strategies of Regenerative Medicine
What are iPS and ES?
Where are they differentiated?
- Patient derived pluripotent cells (iPS) & Non-Patient derived pluripotent cells (ES)
- in vitro
Induced Pluripotent Stem Cells (iPS)
What is the goal of this process?
There is potential for what negative outcome with this process?
Develop pluripotent SC starting from differentiated somatic adult cells by introducing TFs to induce properties of ES cells
Very high potential for teratoma formation
