Cell Signaling and Tissue
Engineering
Why Cell Signaling?
• Complex system of
communication
• Affects a cell’s ability to
respond to its environment
Cell signaling affects:
• Development
• Tissue Repair
• Immunity
• Movement
• Diseases
What Happens When Cells Miscommunicate??
Diabetes
Rheumatoid Arthritis
Cancer
Lupus
Multiple Sclerosis
Asthma
How Do Cells Send Signals?
There are five different types of signaling pathways:
1. Contact
Dependent
2. Autocrine
3. Paracrine
4. Synaptic
5. Endocrine
Why does such a
variety of signaling
pathways exist?
Three Stages to Extracellular Signaling
1. Ligand Binding
–
Ligand binding to receptor
induces conformational change
2. Transduction
–
Amplification and spreading of
signal down specific pathways in
cell
3. Cellular Response
–
–
Cell response to signal
May result in any of the
following:
i.
ii.
iii.
Gene transcription
Cell proliferation/division
Cell survival
Extracellular Signaling in a Nutshell
The signaling cell
produces a particular
type of signal molecule
that is detected by the
target cell. The target
cells possess receptor
proteins that recognize
and respond specifically
to the signal molecule.
Seem Simple? Think Again
How many different signaling molecules
exist?
•
HUNDREDS
How do you think this effects
a signals ability to be transduced?
•
Each cell responds selectively
to a mixture of signals
–
–
Disregards some
Reacts to others
What complications can arise?
•
•
One signal, binding to one type of receptor protein, can cause a variety of effects in the
target cell
Cells have an assortment of different receptors, making them sensitive to many signals
Cellular Suicide?
What do you think happens in the absence of
signals?
• In most cases, cells kill themselves.
Strengthening and Maintaining a Signal
Recall Synaptic Signaling Pathway
How can we alter/strengthen a signal?
• Neuroplasticity – ability to reorganize neural
pathways based on new experiences
4 Stages to Neuroplasticity
1. Induction
– Neuron realizes input needs to be changed
2. Selectivity
– Type of change is based on input parameters (gain
or loss)
3. Expression
– Synaptic efficiency is changed
4. Maintenance
– Change is maintained over long period of time
Wanna Make a Memory?
What is learning?
• The ability to acquire new knowledge/ skills
through instruction or experience
What is memory?
• Process by which learning is maintained over
time
How do you think a memory forms??
CELL SIGNALING!