Stem Cells Flashcards
Cells are considered embryonic stem cells up to the development of the ______
Morula
Morula define:
cluster with no central cavity
Blastula:
- Blastocoel:
Blastula: comes from further division of the morula and the formation of the central cavity. There are now two types of cells
- Blastocoel: the central cavity formed in the blastula
What are the two cell types of the blastula?
Trophoblast cells: form outer layer (can become only placenta cells)
Inner cell mass cells: embryonic stem cells of the blastula (can become any embryonic cell)
TOTIPOTENT:
PLURIPOTENT:
MULTIPOTENT:
UNIPOTENT:
TOTIPOTENT: Can become any cell of the embryonic body or placenta
PLURIPOTENT: can become any cell in the embryonic body
MULTIPOTENT: Can become several closely related cell types
UNIPOTENT: Can only become a single cell type
give an example TOTIPOTENT: PLURIPOTENT: MULTIPOTENT: UNIPOTENT:
TOTIPOTENT: Early or late morula cells
PLURIPOTENT: Inner cell mass cells
MULTIPOTENT: hemopoietic (blood forming) stem cells
UNIPOTENT: muscle stem cells, myoblasts and epidermal stem cells, germline stem cells
Can inner cell mass cells be grown in culture? What are the implications? What potency do these cells have?
Yes
They can be differentiated into any specialized cell type.
They are pluripotent
The inner cell mass given time becomes
inner cell mass + time = embryonic disk
Name the three distinct tissue layers that the embryonic disk differentiates into.
Ectoderm
Mesoderm
Endoderm
Early human embryos resemble other vertebrate animals early embryos this provides evidence for?
The evolutionary relatedness of vertebrates to each other.
Adult stem cells:
Are undifferentiated stem cells, which reside in various tissues and continue to divide at a slow rate for the whole lifetime of the animal.
Self-renewal (of adult stem cells):
Refers to the fact that adult stem cells must maintain their population size and not all differentiate. The rate of self renewal is about 50%
Somatic stem cells are
Adult stem cells
What is the only source of pluripotent adult stem cells?
The umbilical cord
The majority of adult stem cells display what types of potency?
Multipotent ex Mesenchymal stem cells adipose-derived stem cells endothelial stem cells
Bone marrow tramsplants were pioneered by
E donnell Thomas
Stem cell niche:
the microenvironment in which the stem cell lives.
The niche interacts with the stem cell to determine it’s developmental fate
- by preventing or stimulating differentiation and mitosis (each independently)
Specialization of a cell involves what?
Switching off unneeded genes, and turning on needed genes. Therefor making sure the cell in only utilizing energy and space on what it needs for its function.
CHARACTERISTICS of Adult Stem Cells
1.) Exhibit self-renewal by mitotic cell division.
2.) Reside in various tissues alongside differentiated cells.
3.) Continue to divide indefinitely at relatively slow rates.
4.) Rare - only about 1% of bone marrow cells are stem cells.
5.) Plain-looking (nondescript appearance) – difficult to identify.
6.) Retain various levels of potency (developmental potential).
7.) Maintain the normal turnover of cells within tissues.
8.) Act as a repair system – replace damaged cells.
9.) Following tissue damage, the niche signals to adult stem cells to
divide and repair the tissue.
Human tissues that contain adult stem cells:
SKIN HAIR FOLLICLES INTESTINAL EPITHELIUM HEART BRAIN BONE MARROW SKELETAL MUSCLE
Satellite cells are?
The true adult skeletal muscle stem cells
Stem cells of the hair follicle
Reside in the bulge region (midway into root) Migrate down towards the matrix and up towards the sebaceous gland and the epidermis.
Where do adult stem cells reside in the small intestine?
In the crypts of the Small intestine
Intestinal stem cells spawn cells which migrate?
Upwards, towards the top of the villus.
As intestinal epithelial stem cells migrate upward they differentiate into _____ cells or ______ cells.
Brush border absorptive cells
Secretory cells
Paneth cells:
1) migrate downwards into the crypt.
2) secrete Wnt (signalling proteins) which help the cell to maintain its stem cell character.
Wnt proteins:
Are morphogens which act as local mediators of multiple aspects of development via a paracrine mechanism
Morphogens:
Are signalling proteins which regulate development (dictate eventual morphology)
Wnt-beta-catenin pathway
act by regulating proteolysis of the multifunctional beta-catenin protein (deals with cell adhesion and gene regulation).
Stem cells in the epidermis reside in the?
Basal layer of the epidermis adjacent to the uppermost layer of the dermis
Where do hemopoietic cells reside?
In the bone marrow.
Which types of cells doe hemopoietic cells give rise to?
All cells in the blood stream.
- Lymphocytes (B and T)
- eosinophil, basophil, neutrophil
- monocyte
- Megakaryocyte –> platelets
- RBCs
Clone define:
Cells which are biologically identical from the same ancestor
Reproductive cloning:
create a new animal
Therapeutic cloning:
Repair a damaged tissue
Somatic Cell Nuclear Transfer (SCNT):
1) Unfertilized egg from an adult female.
2) remove DNA from this cell
3) Take a cell from adult tissue and fuse it or inject it into the egg cell
4) it grows to an embryo and you can either culture it or have it grow into a calf.
Does SCNT work for Therapeutic cloning and Reproductive cloning?
Yes
using SCNT to clone a frog:
It is the same, nuclear material from the unfertilized egg can be destroyed with UV radiation though.
Cloning a carrot:
1) Section carrot
2) break it down to single cells in rich media
3) single cell will divide until multiple embryo and therefor carrots are formed
SCNT on a cow:
1) Must remove meiotic spindle and chromosomes (likely true for SCNT)
2) electric pulse used to fuse somatic cell with enucleated egg
3) continue as before
The first cloned mammal was?
Dolly, the sheep.
Idaho Gem:
The first cloned Mule. Cloned by Dr. Ken White at USU.
Cell Surface Identity Markers (antigens)
Are anything on the cell which can be recognized. These can cause ‘rejection’ of an organ transplant.
Unless… you use therapeutic cloning
Therapeutic cloning utilizes SCNT to make ____ with the same ______ as the patients cells.
Pluripotent embryonic stem cells
Cell-surface antigens
Autologous:
Means from the same individual
Autologous cells:
Cells from that individual or from cells cloned from that individual. No immunological rejection.
Diabetes mellitus 1 could be cured by what means?
By transferring cloned, induced, pancreatic beta cells into the person.
a small number of transcriptional regulators can
convert cells into another type of cell.
Name an example of transcriptional regulators being used to convert cells to a different cell type
liver cells in culture –> neuronal cells by using 3 nerve specific transcriptional regulators
Induced Pluripotent Stem (iPS) Cells:
1) fibroblasts taken from the skin
2) cultured
3) introduction of DNA with three transcription factors (oct4, Sox2 and klf4)
4) induced pluripotent stem cell (iPS cell)
Are iPS cells autologous?
Yes
iPS cells and personal drug discovery:
Drugs can be tested on a person specific basis in vitro
Cells can be studied to find patient specific causes of disease
Chemically-induced Pluripotent Stem Cells (CiPS) are:
- programmed using chemicals alone (no need for vectors or virus delivery into patient cells)
- require a combination of chemicals
- patient specific cells would be produced
Chemically-induced Pluripotent Stem Cells (CiPS) are:
- programmed using chemicals alone (no need for vectors or virus delivery into patient cells)
- require a combination of chemicals
- patient specific cells would be produced
CiPS cells are more or less likely to form a tumor?
Less likely, as they do not need to splice into the DNA like a virus or a vector.
