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