Stem Cell Applications Flashcards
A _______ cell is a primitive cell that can either self-renew or give rise to more specialized cell types
Stem
Stem cells often have __________ morphology than more differentiated cells.
They have more ________ shape, depending on tissue lineage.
They have a ____ ratio of cytoplasm:nucleus.
Damaged tissue can release factors that activate stem cells.
Simpler
Circular
Low
What are some characteristics of stem cells?
Not terminally differentiated
Can divide without limit
Undergo slow division
Adult stem cells are ________-specific, and their proliferative potential is referred to as their ___________
Tissue; potency
____________ refers to the ability to give rise to all cells of an organism, including embryonic and extraembryonic tissues (cells which support embryonic development)
Totipotent
What is the primary example of totipotency?
Zygote
___________ refers to the ability to give rise to all cells of the embryo and subsequently adult tissues
Pluripotency
What is the primary example of pluripotency?
Embyronic stem cells
____________ refers to the ability to give rise to different cell types of a given lineage
Multipotency
What is the primary example of multipotency?
Adult stem cells
Where are pluripotent cells located (in terms of cell type)
Blastocyst (inner cell mass)
The blastocyst’s outer cells will become the first embryonic epithelium (____________________), which will form the placenta and extraembryonic tissues
Trophectoderm
Once the zygote reaches the ____-cell stage, it is no longer considered totipotent
16
___________ stem cells are charged with maintaining cellular homeostasis, because they are already partially committed
Multipotent
[these will serve to replace damaged cells, sustaining cellular turnover]
The benefits to stem cell research include self-renewal and plasticity, but these are also factors that characterize _________ cells
Cancer
Each tissue has a fixed number of this type of cell population; they are programmed to have a fixed number of divisions and are controlled by short range signals that operate for a few hundred cell diameters
Founder stem cells
What type of stem cells define the size of large final structures?
Founder stem cells
What type of stem cells divide frequently but are programmed to have a finite number of divisions?
Transit amplifying cells
[these serve as part of the strategy for growth control]
For a steady pool of stem cells, 50% of daughter cells must remain stem cells. This is accomplished through what 2 methods?
Divisional asymmetry
Environmental asymmetry
What is divisional asymmetry?
Asymmetric division may create 2 cells, one with stem cell characterisitics and another with factors that give it the ability to differentiate
What is environmental asymmetry?
Division makes 2 identical cells but the environment influences one of them to differentiate
In asymmetric division of stem cells, the choice of which cell will differentiate is determined by asymmetry in the originally dividing stem cell.
In independent choice, what determines which cell will differentiate?
Choice is determined stochastically and/or by the environment
What hypothesis dictates that some tissue’s stem cells selectively retain original DNA as a way to prevent genetic errors in stem cells?
Immortal strand hypothesis
In the immortal strand hypothesis, the original DNA strand is maintained in the stem cell generations. What cell type receives the newly synthesized strand?
Transit amplifying (committed cells)
What happens when embryonic stem cells are put back into the blastocyst?
They can integrate well with the embryo and develop into different cell types
What happens if embryonic stem cells are injected into an embryo at a later stage or into an adult?
They fail to receive appropriate sequence of cues for proper differentiation and can become a tumor (teratoma)
What is the defining feature of a teratoma?
Its ability to differentiated into a wide range of tissues; they do not display axis formation or segmentation
How are instructions provided to ES cells prior to integrating in vivo?
They will be mixed with the desired cell type in vitro in order to give them the “instructions” on what cell type to become
_______ cells may be derived at high frequency from good quality embryos.
Serum containing medium plus mouse or human embryonic _______ feeder cells
Serum free medium with serum replacement and basic ______
_____ and related cytokines have no effect
ES
Fibroblast
FGF
LIF
An ES cell harvested from the inner cell mass and placed under the influence of retinoic acid, insulin, and thyroid hormone would become what cell type?
Adipocyte
An ES cell harvested from the inner cell mass and placed under the influence of retinoic acid only would become what cell type?
Neuron
An ES cell harvested from the inner cell mass and placed under the influence of MSCF, IL-3, and IL-1 would become what cell type?
Macrophage
An ES cell harvested from the inner cell mass and placed under the influence of dibutyryl cAMP and retinoic acid, what type of cell will it become?
Smooth muscle
An ES cell harvested from the inner cell mass and placed under the influence of FGF, FGF-2, EGF, and platelet-derived growth factor will become what cell type?
Astrocytes and oligodendrocytes
In directed ES cell differentiation, the ES cell is first exposed to a __________ signal so that it becomes a committed precursor cell. That cell is then exposed to specific signals for _________ and ____________ to produce large numbers of the mature cell type in pure form
Committment
Growth; differentiation
ES cell therapies are reliable, and have highly reproducible results in generating cells with what type of potency?
Pluripotency
What are some diseases that can be treated using ES cell therapies?
Immunodeficiencies Diabetes Parkinson's Spinal injury Demyelination Myocardial infarction
Human ES cells express genes found in pluripotent cell populations. What transcription factors are essential for the establishment and maintenance of pluripotent stem cells in the embryo?
Nanog
Oct4
Sox2
FoxD3
_________ is a TF required for early stages of pluripotent cell differentiation
GCNF
__________ and _________ are growth factors found in pluripotent cells
Cripto; GDF-3
In taking a slightly less differentiated cell like a mesenchymal or stromal stem cell and turning on certain genes using Nanog, Oct4, Sox2, and FoxD3, scientists are able to induce ____________
Pluripotency
________ stem cells are found in tissues and respond to demands of growth and repair. Restrictions on these are strictly imposed by molecular restraints on gene expression
Adult
True or false: adult stem cells may show a relaxation of molecular restraints on gene expression in an altered environemnt, possibly accounting for plasticity
True (but usually observed at low frequency)
True or false: evidence supports the contention that, under the right conditions, adult stem cells can replace embryonic stem cells
False
Where do hematopoietic and stromal stem cells come from?
Bone marrow
__________ stem cells are found in blood components like cord blood, bone marrow, and peripheral blood
Hematopoietic
____________ stem cells are found in connective tissues like Wharton’s Jelly, bone marrow, adipose tissue, and tooth pulp
Mesenchymal
True or false: cord blood stem cells are undifferentiated and can become completely pluripotent
False, they are undifferentiated but cannot become completely pluripotent
What are the 2 main strategies for generating patient-specific cells of a desired type?
Utilizing primary cells (reprogramming)
Utilizing pluripotent cells that are patient derived or non-patient derived (directed differntiation)
Neuroregeneration is an adult stem cell therapy technique using ASCs derived from ______ and _______ tissue
Bone marrow; adipose
[these have the capacity to differentiate in vitro and in vivo into chondrocytes, myoblasts, osteoblasts, pancreatic beta cells, and neuronal-like cells)
True or false: neural stem cells can repopulate the CNS; granfted neural stem cells can adjust their behavior and function to match their location
True!
Hippocampal cells implanted into olfactor bulb precursor pathway become incorporated into the olfactory bulb
What is the biggest disadvantage to utilizing early adult stem cells as treatments for various conditions?
Immune rejection is possible if stem cells are derived from a blastocyst created through IVF
[if genetically different, grafted cells are rejected by host, so an identical genotype is required]
What is the alternative to adult stem cell therapies where a nucleus is taken from somatic cell of patient and injected into the oocyte of a donor, replacing the oocyte nucleus?
Somatic Cell Nuclear Transfer
Ideally adult cells could be converted into ES like cells by manipulating gene expression directly. This would involve 4 key gene regulatory factors, what are they?
Oct3/4, Sox2, Myc, and Klf4
[however, when these are used the yield is low and they are not identical to ES cells]
What alternative method for stem cell therapy produces cells which are custom made for the patient and solves the tissue rejection problem, since the cells will express the patient’s genes?
SCNT
What are the cells called that are generated by reprogramming differentiated somatic cells into pluripotent stem cells?
Induced Pluripotent Stem Cells (iPSCs)
What is the general process for SCNT?
Combine donor oocyte (with nucleus removed) with recipient somatic cell
Stimulate cell division
Extract inner cell mass and culture
What are the 2 major challenges to SCNT in disease treatment?
Inefficient, because you may need hundreds of oocytes to reach therapeutic quantity
Technically demanding, needs to be available in hospitals
