Stem Cells Flashcards
asymmetrical division of stem cells
division gives rise to 1 cell with stem cell characteristics and the other with the ability to be differentiated
adult stem cells
- what are they
- what do they respond to
mature stem cells; tissue specific (epidermal stem cells, intestinal stem cells, etc.)
- responds to demands of growth/repair
totipotency
- what is it
- example and location
ability to give rise to all cells of an organism, including embryonic and extraembryonic tissues
ex: embryonic stem cells in the zygote
pluripotency
- what is it
- example and location
ability to give rise to all cells of the embryo and subsequently adult tissues
ex: embryonic stem cells in the blastocyst
multipotency
- what is it
- example and location
ability to give rise to different cell types of a given lineage (endoderm, ectoderm, or mesoderm)
ex: adult stem cells in various tissues
how stem cells can treat diabetes
cultured pluripotent stem cells can be cultured to become pancreatic islet cells that can be used to treat diabetes
how stem cells can treat leukemia/used for chemotherapy
cultured pluripotent stem cells can be cultured to become bone marrow cells
founder stem cells
- what are they
- what do they do
- where are they used
fixed number of divisions; controlled by short range signals; each tissue has fixed number of these cells
- Constantly present in organ
- Determine organ size via signaling
- used in proportions of the body that are determined early
transit amplifying cells
the daughter cell that has the ability to differentiate in stem cell division; limited, finite number of divisions
- part of strategy for growth control
- develop from stem cells
environmental asymmetry
division of stem cells that is influenced from the environment; may influence or alter 1 cell
immortal strand hypothesis
in stem cell division, the self-renewal cell retains exact same DNA as the parent cell, and the daughter cell gets new, mutated DNA
embryonic stem cells
- derived from where
- development
- derived from blastocyst stage of embryo
- can proliferate indefinitely, unrestricted development
- develop into different cell types
- can become a tumor
teratoma
a tumor made up of several different types of tissue, such as hair, muscle, or bone; typically form in the ovaries, testicles, or tailbone and less commonly in other areas
how do ES cells give rise to teratomas
ES cells can differentiate into many different types of tissues; on their own, the ES cells are incapable of generating the body plan; disorganization causes tumors
- tumor is made of cells from all germ layers
Nanog
Oct4
Sox2
FoxD3
transcription factors that are essential for establishment and maintenance of pluripotent stem cells in the embryo
GCNF
transcription factor; required for early stages of pluripotent cell differentiation
Cripto and GDF-3
growth factors found in pluripotent cells
hematopoietic stem cells
- where are they derived from
- where are they found
- derived from bone marrow
- found in cord blood, bone marrow, peripheral blood
stromal (mesenchymal) stem cells
- where are they derived from
- where are they found
- derived from bone marrow
- connective tissues, many other tissues (liver, muscle, nerve, etc)
cord blood stem cells
third main type of stem cell; undifferentiated cells
- no gene manipulation
- can be “banked”
three main sources of stem cells
embryonic
adult
cord
two places in the body where mesenchymal stem cells can be harvested
bone marrow (BMSCs) adipose tissue (AMSCs) from liposuction
adult stem cell therapy:
- where they differentiate
- what they can differentiate into
they have the capacity to differentiate in vitro and in vivo
–> chondrocytes, myoblasts, osteoblasts, pancreatic beta-cells, and neuronal cells
somatic cell nuclear transfer
SCNT cells
nucleus is taken from a somatic cell of a patient and injected into the oocyte of a donor, replacing the oocyte nucleus
–> blastocyst generated and ES cells isolated
Ex: Dolly
Oct3/4, Sox2, Myc, KIf4, Nanog, Lin-28
transcription factors/gene regulatory factors; can induce adult human cells to exhibit properties of ES cells
what occurs when adult stem cells are injected into the fibroblast
they become ES-like cells
- ability to differentiate into other cell types
- yield is low and not identical to ES cells
iPS cells
induced pluripotent stem cells
a type of pluripotent stem cell that can be generated directly from adult cells
what are the therapeutic potentials and ethical benefits of using iPS cells and SCNT cells
- solves tissue rejection problem (cells express patient’s genes)
- cells are custom made for patients
- enable reprogramming of adult cells while omitting embryo step
- study disease development and develop drugs
in somatic cell nuclear transfer, what is the downside of stopping production at the fusion step
this prohibits cloning which restricts any therapeutic application; the cell doesn’t divide if you restrict this
in somatic cell nuclear transfer, what is the downside of stopping implantation of the SCNT
restricts reproductive cloning
but allows therapeutic research to continue
challenges for SCNT in disease treatment
- inefficiency (may needs hundreds of oocytes)
- technical demand - needs to be available in many or all hospitals
