Stem Cells Flashcards
A primitive cell that can either self-renew or give rise to more specialized cell types. It is highly regulated.
Stem cell
*progenitors are more differentiated (the original origin ones)
What are characteristics of stem cells?
- not terminally differentiated
- can divide without limit (bc telomerase expression)
- undergo slow division
- divide into 1 stem cell and 1 differentiated cell
Adult (mature) stem cells are known to be ________. They are committed to a specific lineage of the ectoderm, mesoderm, endoderm.
Tissue specific
The proliferative potential of a stem cell is know as its _______
Potency
Describe totipotency
- ability to give rise to all cells of an organism (embryonic and extra embryonic tissue)
- ZYGOTE of embryonic stem cell
Describe pluripotent
- ability to give rise to all cells of the embryo (not extra embryonic cells)
- blastocyst of embryonic stem cells
Describe multipotency
Ability to give rise to different cell types of a given lineage
*adult stem cells
(Adult/tissue/somatic stem cell)
T/F
Pluripotent embryonic stem cells can be isolated and cultured and grown into different tissue types such as pancreatic islet cells, hematopoietic cells, cardiomyocytes, neurons, and hepatocytes
TRUE
Ectoderm cell’s can become
Skin or neural cells
What makes you pretty: your outside (skin) and smarts (brain)
Endoderm cells can become
Lung, thyroid, or pancreas
Mesoderm cells can become
Cardiac cellls, hematopoietic, mesenchymal, or smooth muscle cells
Cultured pluripotent stem cells make:
_____ for leukemia patients
_____ for Parkinson’s and AD
_______ for heart disease
________ for diabetes
Bone marrow
Nerve cell
Heart muscle
Pancreatic islet cells
- short range signal determines the populations during development
- programmed to have a fixed number of divisions
- define the size of large final structures
Founder stem cells
*populations stay small but transit amplifying divisions let them generate and renew big adult structure
How often to transit amplifying cells divide ?
Frequently
Where do transit amplifying cells come from
Stem cell division; it is the cell that is carried on to be more differentiated
- it is committed
- have a finite number of divisions
Stem cells have divisional asymmetry. What does this mean? How is it different than environmental asymmetry ?
- division of stem cells = 50% exact stem cells with original DNA and 50% transit amplifying cells with committed lineage
- environment asymmetry means that environmental factors influence cell differentiation
What hypothesis summarizes that in asymmetrical stem cell division one daughter cell becomes a new stem cell with the exact DNA copy and the other daughter cell (transit amplifying cell) becomes differentiated and gets newly synthesizes strand of DNA
Immortal strand hypothesis
- way to prevent genetic error in stem cells
- result of semi-conservative DNA replication
- transit cells may get errors in newly synthesized DNA
What markers in the cell’s DNA is involved in stem cell differentiation and cause the restriction of DNA expression therefore determining the type of cell a stem cell with turn into
Epigenetic markers
Silencing of some parts of genes by methylation
In ES from the blastocyst, then can be placed back into ____ to integrate with the embryo, but if injected at a later stage or into an adult they will fail to differentiate properly and can become a tumor
Blastocyst
Es cells can give rise to what type of tumor? And is the downfall of ES stem cell use
Tertomas (with teeth and hair)
What are the transcription factors that are responsible for making ES pluripotent cells
Nanog, Oct4, Sox2, FoxD3
What are growth factors found in pluripotent cells that make it differentiate ?
Cripto and GDF-4
*GCNF important for early stage pluripotent cell differentiation
Adult stem cells respond to what
Respond to demands of growth and repair
*found in tissues
T/F
Adult stem cells may show relaxation of restrictions in an altered environment that can possibly account for some plasticity
True
*seen in low frequency’s
Adult stem cell therapies
- limited clinical use because cannot change lineage of cells
- reduced teratoma risk
- used in bone marrow transplants
Similarities and differences of hematopoietic and stromal stem cells
Similarities
1. Both come from bone marrow
Difference:
1. Differentiate into two different things
What are hematopoietic stem cells differientiated into
Blood components
- platelets
- RBC
- WBC
What are stromal stem cells differentiated into
*mesenchymal stem cells
Connective tissue and tissues
- bone
- cartilage
- fat
- heart
- liver
- muscle
- nerve
T/F
Cord blood is a type of stem cell that has been known to treat over 70 disease with the possibility of 1000’s new therapies but has ethical boundaries
True
What are two ways you can get pluripotent stem cells
- Patient derived (iPS)
- Non-patient derived (ES)
* useful for cell reprogramin in regenerative medicine
T/F
Adult stem cell therapy can be used in Neuro-regeneration
True
What are some challenges of regenerative medicine
- production of substantial amounts of stem cells
- what cell to transplant
- delivery and proper integration
- immune rejection
- whee to get it from
- stem cells may be immunogenic and promote immune responses
What is SCNT? And Why does somatic cell nuclear transfer (SCNT) not have a risk of immune rejection?
Because patients are using their own stem cells
*nucleus is taken from somatic cell of patient and injected into the oocyte of a donor replacing the oocyte nucleus which makes a blastocyst and then ES cells can be isolated
What are the 4 gene regulatory proteins of ES cells
OCT3, SOX2, Myc, KLf4
Adult stem cells can become ES-like by injecting them into what?
Fibroblast
Called Induced pluripotent stem cells (iPS cells)
- uses recombinant DNA, and TFs (Oct4, Sox2, Nanog) to make pluripotent
- HIGH TERATOMA POTENTIAL
What is combined in SCNT in the beginning step
Denucleated egg cell with somatic cell from patient
Where do you stop the SCNT process to stop both therapeutic application and cloning ability? And where do you stop the SCNT cycle to allow therapeutic research and stop cloning ability?
- At fusion Site
- Prohibiting implantation of blastocyst, but allowing culturing of pluripotent cells
* Dolly was a clone made by this process
Difference between “normal” formation of ES cells and “SCNT” formation of ES cells
“Normall” - ES cell from blastocyst
SCNT- ES cell from SCNT derived blastocyst
Challenges of SCNT treatment
- can be used in T1DM
1. Inefficient (may need hundreds of oocytes)
2. Technically demanding (needs to be available in many/ all hospitals)
What are sources of oocytes?
Self, mother, relative, egg bank
