Cell Differentiation Flashcards
Important features of Stem Cells:
1) Unspecialised
2) Can differentiate (see semester 2)
3) Self-renewal (i.e. regenerate / lifelong)
Stem cells have an unlimited capacity to…
…self-renew and produce ‘differentiated’ cells of various types
The ‘progenitor cells’, midway down have…
…limited capacity to self-renew and
and differentiate
Terminally differentiated cells do not…
…self renew and do not differentiate
Totipotent stem cells are known as the…
…‘ULTIMATE’ stem cell
Totipotent stem cells have the ability to…
…differentiate into ALL body cell
types, including cells that make
the placenta
Pluripotent stem cells can differentiate into the…
…3 ‘germ’ layers of the human body
Multipotent stem cells can differentiate into…
… limited cell types
The 3 germ layers of pluripotent stem cells:
Ectodermal, Mesodermal and Endodermal
Ectoderm will form…
… epidermal layer of skin
Endoderm will form…
…the lining of the gut, the liver, and the lungs.
The neural ectoderm will form …
…the nervous system
The gray crescent is the site where…
… major cell movement will begin.
Mesoderm will form…
…muscle, bone, kidneys, blood, gonads, and connective tissue.
Stem cells are NOT named after their characteristics, but…
… the type of tissue that they can differentiate into
Within multicellular organisms, tissues are…
…collections of different types of specialised cells that function together
The evolution of multicellular life corresponded with…
…an increase in atmospheric oxygen levels ~1.8 billion years ago
Cells divide by…
…binary division i.e., one cell produces two offspring cells
For differentiation one of the offspring cells must retain…
…phenotypic plasticity and self-renewal properties, whilst the other must
differentiate along a given lineage
The niche is central for…
…cellular differentiation & maintaining stem cells
Whats the stem cell niche?
The niche is a special microenvironment that provides physical signals.
1) Cell-cell contact
2) Cell matrix interactions
3) Mechanical
4) Biochemical (growth factors, hormones)
In vitro studies formally show that asymmetric cell division is dependent on…
…mechanical cues, even in the absence of biochemical signals.
Cell adhesion molecules are expressed on the…
…plasma membrane.
The extracellular domain interacts with …
…the extracellular matrix i.e., collagen
The intracellular domain interacts with…
…the cytoskeleton
The mechanical interaction between the extracellular matrix and the cell cytoskeleton allows the cell to…
…exert traction forces
The mechanical interaction between the extracellular matrix and the cell cytoskeleton allows the cell to exert traction forces.
These forces are transmitted
through…
…intracellular pathways to the nucleus in a process called ‘mechanotransduction’
The mechanical interaction between the extracellular matrix and the
cell cytoskeleton allows the cell to exert traction forces
These forces are transmitted
through intracellular pathways
to the nucleus in a process
called ‘mechanotransduction’
This results is a pattern of …
…specific gene expression
changes in the cell
Integrins anchor…
…progenitor cells
Integrins anchor progenitor cells permitting…
… differentiation
Cadherins anchor…
…the stem cells to niche cells and ECM permitting self-renewal.
Cadherin proteins hold…
…stem cells in the niche and provide mechanical signals.
Progenitor cells (differentiating)
rely on…
…integrin proteins for
mechanotransduction
What are isotropic forces?
pulling & stretching. Pull the cytoskeleton equally.
In vitro models demonstrate that ‘isotropic forces’ - pulling & stretching
of the cytoskeleton along with differential forces exerted by the ECM /
niche cells, plus the partial pressure of oxygen initiate…
…differentiation
Anisotropic forces pull…
…the cytoskeleton unequally, causing
the cell to elongate.
- Forces are also applied back from the
niche
Using progenitor cells, the effect of isotropic forces (soft) on cell
differentiation can be appreciated by …
…in vitro modelling
Using progenitor cells, the effect of isotropic forces (soft) on cell
differentiation can be appreciated by in vitro modelling
In this very clean experimental system, the cells on the left will form …
…cardiac muscle cells (cardiomyocytes)
Using progenitor cells, the effect of isotropic forces (soft) on cell
differentiation can be appreciated by in vitro modelling
In this very clean experimental system, the cells on the left will form
cardiac muscle cells (cardiomyocytes), whereas the cells on the right
will form…
…neuronal cells
Using progenitor cells, the effect of isotropic forces (soft) on cell
differentiation can be appreciated by in vitro modelling
In this very clean experimental system, the cells on the left will form
cardiac muscle cells (cardiomyocytes), whereas the cells on the right
will form neuronal cells. In both cases…
…differentiation is altered.
- You will notice the ‘random’ dendrite formation in the neuronal cells.
slide 19, 20, 21, 22, 23.
