Cell Signaling and Tissue Engineering

Why Cell Signaling?

Cell signaling affects:• Development• Tissue Repair • Immunity • Movement • Diseases

• Complex system of communication

• Affects a cell’s ability to respond to its environment

What Happens When Cells Miscommunicate??Diabetes Rheumatoid Arthritis Cancer

Multiple Sclerosis LupusAsthma

How Do Cells Send Signals?

1. Contact Dependent

2. Autocrine3. Paracrine4. Synaptic 5. Endocrine

There are five different types of signaling pathways:

Why does such a variety of signaling

pathways exist?

Three Stages to Extracellular Signaling1. 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. Gene transcriptionii. Cell proliferation/divisioniii. 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 experienceWhat is memory?• Process by which learning is maintained over

timeHow do you think a memory forms??

CELL SIGNALING!