Transcript Adult Stem Cells

Dolly
1st experimentally cloned animal
Microinjection of nuclei into eggs
QuickTi me™ a nd a H.263 decomp resso r are need ed to se e th is p icture.
Reproductive cloning requires epigenetic modifications to
be reset to state in fertilized egg.
But, this doesn’t work perfectly.
Not yet clear what health problems may arise due to
misexpression of many genes.
Clones = Genetically identical individuals
Two Kinds of Animal Cloning
Reproductive Cloning:
Remove nucleus from egg cell.
Replace it with nucleus from somatic cell (e.g., skin cell)
Stimulate cell to divide (like a fertilized egg).
Implant embryo into surrogate mother.
Therapeutic Cloning (Nuclear Transplantation):
Start the same, but stop development at blastocyst stage.
Remove inner cell mass cells and use to create embryonic
stem cell line.
Stem Cells
Unspecialized cells that renew themselves by dividing
an unlimited number of times.
Under certain conditions they can give rise to cells with
specialized functions.
Embryonic Stem Cells:
Derived from undifferentiated cells from early-stage embryos
(blastocyst stage).
Pluripotent: Have the potential to give rise to any kind of cell in the
body.
Therapeutic Cloning
2. Induce cells to
develop into specific
cell type that patient
needs
1. Make embryonic
stem cell line from
patient
Use to treat diseases
such as Parkinsons
or diabetes (right)
Mature neurons (red) and glial cells (green)
derived from human embryonic stem cells
Blood cells (red) derived from human embryonic
stem cells
Can combine stem cell & gene therapy
Replace bad copy of
gene with good one
Make embryonic stem cells
from “patient”
Stem Cells
Unspecialized cells that renew themselves by dividing
an unlimited number of times.
Under certain conditions they can give rise to cells with
specialized functions.
Embryonic Stem Cells:
Derived from undifferentiated cells from early-stage embryos
(blastocyst stage).
Pluripotent: Have the potential to give rise to any kind of cell in the body.
Adult Stem Cells:
Found in a variety of tissues and organs.
Multipotent: Able to give rise to a limited range of cell types.
Adult Stem Cells
Multipotent
Bone marrow
Blood stem cells
Stromal stem cells
Some adult stem cells
may be pluripotent
This potential ability to
differentiate into wider
array of cells is called
plasticity.
How may plasticity be
regulated???
Adult Stem Cells
Potential Uses:
Bone marrow transplants.
Hope to be able to get adult stem cells to differentiate
into wider range of cell types.
May be able to regenerate tissues using cells from one’s
own body, avoiding tissue rejection problems.
Limitations:
May be limited in range of cells they can give rise to.
e.g., Blood stem cells may be able to produce
blood cells, but not brain cells.
Can only obtain a relatively small number of cells from
an individual & they don’t grow well in culture.
Challenges in stem cell therapy
Learn what causes stem cells to become distinct kinds of
specialized cells, such as insulin-producing pancreatic cells or
nerve cells, and how to more precisely control this process.
Demonstrate plasticity of adult stem cells and learn how to
control this.
Overcome technical (& political) barriers for working with
human embryonic stem cells.