Stem Cells Flashcards by Lauren M

stem cells

A primitive cell; can either self-renew or
give rise to more specialized cell types
• Single stem cells differentiate into
multiple, functional cell types
• Stem cells functionally reconstitute a
given tissue in vivo

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characteristics of stem cells

– Not terminally differentiated
– Can divide without limit
– Undergo slow division
– When divide gives rise to 1 cell with stem cell characteristics and the
other with the ability to be differentiated

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potency

proliferative potential

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totipotency

Ability to give rise to all
cells of an organism, including
embryonic and extraembryonic tissues
(cells which support embryonic
development)

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ex of totipotency

zygote

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pluripotency

Ability to give rise to all
cells of the embryo and subsequently
adult tissues.

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ex of pluripotency

(embryonic stem cells)

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multipotency

Ability to give rise to

different cell types of a given lineage.

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ex of multipotency

adult stem cells

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founder stem cells

• Each tissue has fixed number of
founder cell populations
• Programmed to have fixed number of
divisions
• Controlled by short range signals that
operate for a few hundred cell
diameters
• Define the size of large final structures

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transit amplifying cells

-cells that
divide frequently
• Transit from a cell with stem cell characteristics to a differentiated cell
• Leave the basal layer and incorporate
into the layers above
• Programmed to have limited number of
divisions-> finite
-part of strategy for growth control
-committed

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divisional asymmetry

asymmetric
division may create 2 cells, one with stem
cell characteristics and another with
factors that give it the ability to
differentiate

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environmental asymmetry

Division makes 2 identical cells but

environment may influence/alter 1 cell

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immortal strand hypothesis

• Some tissues’ stem cells selectively retain
original DNA
This daughter cell will retain stem cell
characteristics
• Original strand of DNA preserved in stem
cells from generation to generation
• Second cell gets the newly synthesized
strand

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embryonic stem cells

-Derived from the blastocyst stage of embryo
• Capable of proliferating indefinitely in culture
• Unrestricted developmental potential
• When put back in blastocyst they can integrate well with the embryo
• Develop into different cell types
*can become tumor

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what can give rise to teratoma

ES cells

ES cell therapies

-successful treatment of animal models of disease

what TF are essential for establishment and maintenance of pluripotent stem cells

(Nanog, Oct4, Sox2 and FoxD3)

what are GF found in pluripotent cells

Cripto and GDF-3

what is required for early stages of pluripotent cell differentiation

GCNF

adult stem cells

Found in tissues; responds to demands of
growth/repair
-Strictly imposed by molecular restraints on gene
expression
-Restricted capacity and growth potential
• Harvested cells retain properties of the
original tissue type; have memory of its
developmental history

Hematopoietic and Stromal Stem Cell

• Both come from bone
marrow
• Differ in what they can be
differentiated as

HSC

blood components

MSCS

connective tissues, tissues

adult stem cell therapies

– Bone marrow derived mesenchymal stem cells (BMSCs): transplant – Adipose derived mesenchymal stem cells (AMSCs): liposuction

what is as serious problem in adult stem cells

immune rejection

somatic nuclear transfer

nucleus taken from somatic cell of patient and injected into oocyte of a donor replacing the ooctye nucleus – Blastocyst generated from this hybrid oocyte and ES cells isolated

what are key gene regulatory proteins that determine ES cell character

Oct3/4, Sox2, Myc and KIf4.

somatic cell nuclear transfer (SCNT)

– Combines cloning methods with embryonic stem cell technology – Produces cells which are custom made for patient – Solves tissue rejection problem as cells express the patient’s genes – ES cells from patients with certain diseases; study disease development and develop drugs – Research has enabled reprogramming of adult cells while omitting embryo step

induced pluripotent stem cells (ips cells)

- reprogram differentiated adult cells back to plurpotency | - generates patient specific ips cells

what TF does ips cells use

oct 4, sox 2, nanog, lin28

what is a drawback to ips

very high potential for teratoma formation

somatic cell nuclear transfer

1) remove egg nucleus 2) add somatic cell nucleus of recipient 3) stimulate cell division process 4) extract ICM from blastocyst 5) culture pluripotent embryonic stem cells

Ethical restrictions with SCNT

1) stop at fusion: restricts therapeutic application | 2) stop at blastocysts stage: restricts cloning but therapeutic research continues

challenges of SCNT in disease treatment

``` – Inefficient (may need hundreds of oocytes) – Technically demanding - needs to be available in many or all hospitals ```

source of oocytes in SCNT

Self, | Mother, Relative, Egg bank