Section 1
Cell Differentiation and
Proliferation
Objectives
1. Understand cell signaling influences on cell
differentiation and proliferation.
• Explain how different signals cause different cell
differentiation of the same stem cell.
• Use “growth factors” to explain cell proliferation
promoters and inhibitors.
2. Graph proliferation based on stem cells growth.
• Graph concentration of signal versus number of
colonies that grow.
3. Understand how proliferation is important factor in
tissue engineering.
• Explain importance of culturing large number of
cells for research.
Tissue Engineering
•
Tissue engineering uses
cells, biomaterials, and
engineering methods to
improve or replace
biological functions.
•
In particular, tissue
engineering focuses on
partial and whole tissue
repair and regeneration.
•
Tissue engineering is often used as a synonym
for regenerative medicine. However, regenerative
medicine often focuses on the stem cell based
therapies.
Tissue Engineering
•
There are four fundamental technologies involved in
tissue engineering:
1. Scaffolding for cell proliferation and
differentiation
2. Isolation and culturing of cells
3. Drug delivery system of growth factor
4. Maintenance of space to induce tissue
regeneration
• Together theses technologies are able to assist and
accelerate the regeneration and repairing of defective
and damaged portions or whole tissues.
• We will focus on cell proliferation and differentiation and
well as culturing of cells.
How Is Growth Controlled?
•
Growing cells bind small amounts
of growth factors that stimulate
cell division.
•
Cell surface receptors recognize
each growth factors. They fit like a
lock and key and are very specific.
•
Growth factors work by triggering
downstream effects. Binding often
causing phosphorylation of
proteins which then activates
regulatory proteins that trigger cell
division.
Stem Cells
•
Stem cells have three main characteristics:
1. Not terminally differentiated
2. Capable of unlimited division
3. Self renewing: cells can
remain stem cells or differentiate
Into different cell types
• Stem cells are pluripotent,
meaning stem cells have the
ability to become many cell
types under the right
conditions and signals.
Cell Differentiation
• Differentiation is dependent on the signals and
growth factors the stem cells are exposed to.
Cell Proliferation
•
Once differentiated cells are
created, the goal is to culture
these cells to produce large
numbers of them. Tissue
engineering involves studying
these large cell cultures.
•
Cell signals and growth factors
are used to conduct this task.
•
Some signals can inhibit the
growth of cells, so its our job as
tissue engineers to figure out
what growth factors and signals
increase cell proliferation the
best.
Student Activity
Goal:
Add growth factors to stem cells to
determine the best growth factor for
cell proliferation.
Student Activity
Materials:
•
Agar plates
•
Yeast
•
Boric acid
•
Ethanol
•
Sucrose
•
Apple juice
•
Vinegar
•
Glass rods
•
Test tubes
Student Activity
Procedure:
1. Apply “growth factors” to petri dishes using the
micropipettes.
2. Add differentiated stem cell culture to petri dishes.
3. Allow 48 hours for growth.
4. Count number of colonies on plates.
5. Graph results: The horizontal axis will the different
growth factors and the vertical axis will be the
number of colonies formed.
Note:
•
Use correct micropipetting technique when
administering the growth factors and differentiated
cells. We want to be accurate.
Student Activity
Questions:
•
What is cell proliferation?
•
How did each growth factor affect the yeast growth?
•
Why is cell proliferation important?
•
How can inhibitors be useful to cell proliferation?
•
What others ways do you think you can promote cell
proliferation? Inhibit cell proliferation?
•
Why is culturing large numbers of cells important for
tissue engineering?