Stem Cells and Cell Survival Flashcards
what are known to be the basic structure for all organisms?
Cell
what are the 3 general categories of cells?
- terminally differentiated
- G1 or G0 arrested
- terminally differentiated but replaced by proliferation of less differentiated cells
what are examples of those cells that are terminally differentiated?
- cardiac muscle cells
- neurons
what are examples of cells that are in G1 or arrested in G0?
- skin fibroblasts
- liver cells
those cells in G1 or arrested in G0 resume proliferation under what conditions?
- as needed
- to replace dead/injured cells
what do we call cells that are terminally differentiated but are replaced by the proliferation of less differentiated cells?
stem cells
list 3 examples of stem cells
- epithelial cells lining the GI tract
- blood cells
- epithelial skin cells
list 5 examples of differentiated cells that proliferate
- blood vessel endothelia
- smooth muscle
- epithelial cells of some organs
- fibroblasts
- liver cells
list 5 examples of differentiated cells that do NOT proliferate
- most fully differentiated cells
- skeletal muscle
- neurons
- cardiac muscle cells
- skin epithelium
endothelial cells are stimulated by what type of GFs to proliferate?
VEGF
oxygen-deprived cells secrete ________, leading to the production of new ________ into tissues lacking adequate oxygen.
- VEGF
- capillaries
what type of cells of internal organs are able to proliferate to replace damaged tissue?
endothelial cells
liver cells that are normally in what stage of the cell cycle are stimulated to proliferate if a large number is lost?
G0/1
what are stem cells?
specialized cells which are pluripotent
stem cells have the capability to give rise to
most cells, tissues, organs that make up an organism
the blastocyst stage is where the embryo’s
inner cell mass forms
the inner cell mass contains
embryonic stem cells
only exist briefly
the inner cell mass cannot form an organism. why?
they are unable to form a placenta
totipotent cells can become
every cell & tissue type of an organism
a fertilized egg
pluripotent cells give rise to most
cells, tissue, and organs that make up an organism
stem cells
multipotent cells give rise to
most cells of a particular tissue
blood cells
what are adult stem cells?
less differentiated, self-renewing cells present in most adult tissues
adult stem cells retain the capacity to
proliferate and replace differentiated cells throughout an animals lifetime
what is a key property of stem cells?
self renewal
stem cells divide to produce
- cell that remains a stem cell
- cell that divides and differentiates
stem cells are self-renewing and serve as a source of
differentiated cells throughout life
the role of stem cells is evident in the production of
- blood cells
- sperm
- epithelium (skin & digestive tract)
stem cells at the bottom of the intestinal crypt renew the
colon epithelium
intestinal stem cells finally differentiate into what 3 types of cells?
- absorptive epithelium
- goblet cells
- enteroendocrine cells
give examples of structures that are maintained by their own stem cells
- epidermis
- hair follicles
- sebaceous glands
what type of muscle typically has little cell turnover?
skeletal muscle
what are muscle stem cells known as
satellite cells
satellite cells are normally found in what stage of the cell cycle?
G0
satellite cells proliferate rapidly in response to
injury or exercise
embryonic stem cells can be cultures from
- ICM of blastocyst
- early embryo
mouse embryonic stem cells remain undifferentiated in the presence of
LIF (leukemia inhibitiry factor)
what occurs if LIF is removed from mouse embryinic stem cells?
they aggregate and differentiate
what can stem cell research be used for?
- drug development
- culture pluripotent stem cells for tissues/cell therapy
- to study development and gene control
SCNT stands for
somatic cell nuclear transfer
explain the experiment that resulted in Dolly
- nucleus of adult somatic cells is removed
- nucleus transfered to an enucleated unfertilized egg
- egg is cultured to early embryo stage
- egg is implanted in a foster mother
- clone of nucleus donor is birthed
the Dolly experiment can be used for
therapeutic cloning
what issue is avoided with therapeutic cloning? why?
- immune rejection
- b/c cells are genetically identical
list 3 pros of adult stem cells
- not likely to be rejected
- can differentiate into desired cell type in vitro
- avoid ethical issues
list 4 cons of adult stem cells
- slow proliferation
- can NOT differentiate into many tissue types
- difficult to isolate and purify
- may contain mutations
IPSCs stands for
induced pluripotent stem cells
IPSCs reprograms somatc cells to resemble
embryonic stem cells
how many transcription factors are needed to reprogram adult mouse somatic cells? how are they introduced?
4
- by retrovirus vectors
specific transcription factors activate a program that is also expressed in embryonic cells…what is this program called?
pluripotency transcriptional program
the pluripotency transcriptional program forms an
autoregulatory loop
+ regulate each others expression
what gets activated/repressed in the pluripotency transcriptional program?
- activate: pluripotency genes
- repress: differentiation genes
adult human fibroblasts can be reprogrammed to provide a new way to derive pluripotent stem cells that can be used for
transplantation therapy
what obstacles are bypassed when adult human fibroblasts are reprogrammed?
- original transcription factors can act as oncogenes
- retroviral genes can cause mutations
what is transdifferentiation?
reprogramming somatic cells into other types of differentiated cells
fibroblasts -> muscle cells/neurons
adult stem cells from bone marrow can be developed into
cardiac cells
list some potential uses of stem cells
- stroke
- blindness
- myocardial infarction
- muscular dystrophy
- diabetes
- cancer
- osteoarthritis
- alzheimers
- parkinsons
intra-arterial stem cell transplantation in rats aim to deliver stem cells directly to the
brain without going through general circulation
induced TBI (4 week recovery period)
list some current research w/ stem cells
- aligator stem cells & tooth regeneration
- insulin producing cells to cure diabetes
- stronger patient-specific bones for graphs
