Stem Cells
How long is the transit time of epithelial cell migration
(3-6 days) from birth at bottom of crypt to loss at top of villus
Wnt Proteins are secreted signaling molecules that
(are paracrine signaling molecules) -act as local mediators -morphogens to control many aspects of development in all studied animals
Somatic Cell Nuclear Transfer (SCNT) technique method
-Removal of egg cell DNA from unfertilized egg -Cell fusion or nuclear injection of cell containing genome to be cloned -cell proliferation -early embryo --embryo placed in foster mother (Reproductive Cloning) --or cells from embryo transferred to culture dish (Therapeutic Cloning)
Somatic Cell Nuclear Transfer (SCNT) technique Frog
-Unfertilized egg nucleus destroyed by UV light -nucleus (from skin cells of adult frog) injected into egg -normal embryo -tadpole
Somatic Cell Nuclear Transfer (SCNT) technique calf
-epithelial cells from donor are from oviduct -unfertilized egg cell meiotic spindle and chromosomes removed --donor cell placed next to enucleated egg --electric pulse causes donor to fuse with enucleated egg cell. --reconstructed zygote --cell division --embryo ---embryo placed in foster mother.
How many newly generated stem cells differentiate into more specialized cell types?
50%
How many newly generated stem cells remain as stem cells?
50%
What is the adult stem cell rate of self-renewal?
50%
What is the name of the central cavity within a blastula?
Blastocoel
Name a stem cell therapeutic treatment
Bone Marrow Transplant
Absorptive brush-border cells and mucus secreting goblet cells of villi are examples of
Differentiated cell types, NOT stem cells
Who pioneered Bone marrow Transplants and when? When did he receive a nobel prize
E. Donnell Thomas, M.D 1950's Nobel Prize: 1990
What three layers does the embryonic disk differentiate into?
Ectoderm, Mesoderm, Endoderm
Under appropriate culture conditions _________ _____ cells can be coaxed to differentiate into complex structures such as a _____
Embryonic Stem (ES) retina this has highly significant implications for therapeutic cloning
True or false: Adult Skeletal muscle contains no adult stem cells
FALSE Adult Skeletal muscle contains adult stem cells
True or False- Inner Cell Mass Cells can become any cell of the embryo and any placental cell.
FALSE: Inner Cell Mass Cells can become any cell of the embryo But CANNOT become placental cells
Dolly
First mammal cloned using SCNT (somatic cell nuclear transfer) in 1996
These cells are unipotent adult stem cells, they can only produce gametes (eggs and sperm cells)
Germline
What gives rise to all different types of blood cells in circulation through differentiation
Hemopoietic stem cells
Somatic Cell Nuclear Transfer (SCNT) technique
Importantly the nucleus of the somatic cell is de-differentiated by factors within the eggs cytoplasm
Where do adult stem cells reside in the intestine?
In the intestinal Crypts.
Inner Cell Mass cells of the blastula
Inner Cell mass cells are pluripotent
When does a Blastula (or blastocyst) form? What does it form
It is formed after morula cells divide further and differentiate into two groups of cells, forming a central cavity
Name examples of adult multipotent stem cells
Mesenchymal stem cells Adipose-derived stem cells, endothelial stem cells
Paneth Cells
Migrate down into the crypts and secrete anti-bacterial peptides.
Examples of Unipotent stem cells
Muscle Stem cells (myoblasts) only become muscle cells Epidermal Stem Cells- only become epidermal cells
What cells secrete extracellular Wnt signaling proteins?
Paneth cells
What influences if a newly generated stem cell will remain as a stem cell or differentiate?
Paracrine and contact dependent signals in the stem cell niche.
Leather is
Pickled dermis
Inner Cell Mass cells of the Blastula stage embryo are
Pluripotent
Inner Cell Mass cells are _______ embryonic stem cells that can be grown in culture. They can theoretically be induced to differentiate into _______ specialized cell type of the adult animal.
Pluripotent any
Differentiated cells require specific complements of _______ to perform their functions. give an example of this
Proteins Neurons require specific complements of proteins to perform AP propagation and neurotransmitter secretion.
What % of bone marrow cels are stem cells
RARE: 1%
Create new animal through
Reproductive cloning
Reproductive cloning using _________ the tadpole will be _______ ________ to the adult frog that donated the somatic skin cell with the exception of the ________ ______ within the egg.
SCNT Genetically identical (essentially) mitochondrial DNA Same for Cow
Adult stem cells exhibit _____ _____
Self Renewal.
Tissues known to contain Adult Stem Cells
Skin Hair Follicles Intestinal Ephithelium Heart Brain Bone Marrow Skeletal Muscle
What does the ectoderm become
Skin (epidermis) the nervous system (neurons of brain), and neural crest( forms pigment cells among many other cell types.)
Alternatives to Somatic Cell Nuclear Transfer
Small # of gene transcriptional regulators can convert one differentiated cell type directly into another
Another name for Adult STEM cells
Somatic (of the body) stem cells
How can you achieve Reproductive Cloning or Therapeutic Cloning?
Somatic Cell Nuclear Transfer (SCNT) technique
What regulates the stem cell's development fate?
Stem cell interactions with their particular niche
Multipotent
Stem cells that have potential to differentiate into several different types of closely related (they are lineage-restricted) cell types
During later development of the embryo the inner cell mass cells eventually become
The embryonic disk
What is the stem cell Niche?
The niche is the microenvironment in which adult stem cells reside.
Where do Pluripotent adult stem cells exist?
They exist in small numbers in umbilical cord blood They are RARE!
Which cells form the placenta?
Throphoblast cells
In the Early Morula Stage, stem cells are
Totipotenet
True or False: Adult stem cells reside in various tissues alongside differentiated cells.
True
True or False: Most of your body tissues contain adult stem cells.
True
What do differentiated cells do with unneeded genes. PROGRESSIVE SILENCING
Unneeded genes get turned off or silenced since the proteins from those genes are not needed.
Wnt signalling pathway
Wnt signaling proteins- maintains stem cell character of stem cells Wnt- protein signaling molecule stimulates mitosis.
Zygote is formed when
a sperm fertilizes an egg
Liver cells converted to neuronal cells by
artificially introducing 3 nerve-specific transcriptional regulators
Cell surface identity markers can act as
can act as antigens to trigger rejection of non-autologous transplanted cells.
Significance of Autologous cells
can be transplanted into the same individual without the risk of immunological rejection
Pluripotent
cell has potential to differentiate into any cell type in EMBRYONIC BODY but they CANNOT differentiate into placental cells
Autologous beta cells would have the same _____ ____ ____ as the injected somatic cell
cell surface antigen
Secretory Cells
cells that secrete mucus, antibacterial peptides or gut hormones
Idaho Gem
first cloned mule, clone of brother taz cloned by Dr. Ken White's team at USU. (dean of the college of Agriculture)
When is a Morula formed?
formed after zygote divides, forms a cluster of cells with no central cafity
Autologous means
from the same individual
Hypothetical Use of Therapeutic cloning A person who has type 1 diabetes mellitus (DM1)
has lost pancreatic beta-cells that secrete insulin
Unipotent stem cells
have the potential to differentiate into only a single type of cell.
Where could you find adult stem cells in the hair follicle?
in the Bulge Region
Adult stem cells Continue to divide _________ at ________ _____ for the lifetime of the organism
indefinitely, slow rates
Hypothetical Use of Therapeutic cloning Pluripotent _____ ___ ____ ____ could be created using SCNT, and theoretically induced to differentiate into _____ ____ ____
inner cell mass cells pancreatic beta cells
Endoderm becomes
lining of the digestive system (pancreatic cell) lungs (lung cell) some endocrine cells (thyroid cell)
What does self renewal do?
maintains population of adult stem cells within tissues
As intestinal stem cells differentiate into specialized intestinal cells, (either absorptive brush-border cells or mucus- secreting goblet cells) they
migrate upwards out of the crypts
Most adult stem cells are
multipotent
Personalized embryonic stem cells can be created by using a ______ ____ ____ as the donor nucleus in SCNT
patient's somatic cell
Trophoblast cells can only become
placental cells they cannot become embryonic cells
Therapeutic cloning creates ________ embryonic stem cells bearing
pluripotent the same cell-surface antigens as the patients somatic cell that was used in the SCNT.
Adult stem cells retain various levels of potency meaning
potency (developmental potential)
Signals to stem cells from their niche
prevent or stimulate stem cell mitosis and differentiation
Mesoderm becomes
red blood cells all three types of muscle (cardiac, skeletal, smooth) kidney tubules
Adult stem cells heal wounds by
repairing damaged or missing cells
Adult stem cells maintain tissues by
replacing cells that die and are lost
Hemopoietic stem cells
reside in bone marrow
Where do Epidermal Stem Cells (basal cells) and adult stem cells reside
reside in the basal layer of the epidermis.
Adult stem cells exhibit _____-________ by mitotic cell division
self-renewal
Define Clone
set of cells or individual organism that is essentially biologically identical, by virtue of their descent from a single ancestor cell
Morphogens
signaling molecules that regulate formation of the body during development
Totipotent
stem cells can differentiate into any cell type of the embryonic body or the placenta.
Hemopoietic ('blood forming")
stem cells in the bone marrow are multipotent because they can form many different types of BLOOD CELLS but no other cell type.
Inner Cell mass cells are ____ _____ ___ ___ of the blastula, and they will form the _____ ______
the pluiripotent embryonic stem cells, form the embryo's body
How could you create autologous beta cells?
theoretically created using SCNT of the patient's own somatic cells
Repair damaged tissue through
therapeutic cloning
Nondescript appearance of stem cells means
they are difficult to identify visually
Purpose of Bone Marrow Transplants
to cure leukemia and related bone/blood cancers
Cells resulting from division of adult stem cells must decide?
to remain as stem cells or to differentiate into more specialized cell types
In the later morula stage stem cells are
totipotent
Morula cells are
totipotent
How could you theoretically cure type 1 diabetes mellitus (DM1)
transplant autologous pancreatic beta cells
Autologous beta-cells could be transplanted into the patient's body without.....
triggering immune rejection
Adult Stem Cells are ___________ cells that reside in various adult tissues and that retain the ability to _______ _________, at a slow rate, for the entire _____________ of the animal.
undifferentiated continue dividing lifetime
Cell Differentiation def.
undifferentiated cell morphs into a more differentiated type of cell
Embryonic Stem Cells are formed during cell division of __________ .....
zygote before and after it implants in the uterus