• USA controversy about stem cells in brief.• Where are stem cells?• Cell differentiation• Differentiation game• Video: the story of stem cells• Worksheet: Differentiation of cells

• Last period we looked into the issues surrounding stem cells use in medicine, basically getting the stem cells ready for use in patients.

• While there are many road blocks one that was not highlighted in our activity is the controversy of when life starts.

• This has caused a lot of issues in the USA and slowed stem cell research progress during the Bush administration.

• President Obama allowed for new stem cell lines.• http://www.youtube.com/watch?v=hUxBJApV2ZA

• There have been new breakthroughs in stem cells that allow for regular ol’ cells to be turned into stem cells call IPS cells. We’ll learn more about them later.

• BUT they have also allowed for more people to accept the idea of stem cell therapy.

Where are “Adult” stem cells?

• A common idea is that stem cells can only be found in the embryo.

• Stem cells are in you to help you repair your body or make blood cells.

• This activity aims to counter this by introducing you to current scientific understanding of the range of locations that stem cells can be found in adult tissues.

• The science images have all been taken by leading scientists from across Europe.

• All of the images, apart from the image showing skin cells, were taken using fluorescent microscopy.

• In this technique cell type is inferred through fluorescently labeling a known product of the cell (termed the marker), which sets them apart from other cell types.

• This is why for some organs and tissues scientists can’t definitively say which are the stem cells, as they haven't worked out a marker to use, even though they know that there are stem cells present.

• It took one lab team six years to work out a marker for stem cells found in the eye!

• When stem cells divide they produce progenitor cells as the next step in the pathway of differentiation. As you’ll see in some of the images, scientists may have located progenitor cells but not stem cells in that tissue.

• Draw a person in anatomical position. Stick figure is ok just make the torso a block.

• For this activity you will work in groups of 2 or 3. I will put you in your group.

• You will receive a type of Adult stem cell. In your notes write your stem cell location and information form the sheet.

• You will present to the group where your stem cell is located and the information on the card.

• You should be familiar with your picture and point out any interesting parts.

• In the end you will fold the paper in ½ and hang it on the volunteer cadaver where it would be located

• As audience you will note on your drawing where the stem cell is located and other notes from the presentation.

• break

Differentiation• Up to this point we have studies a general cell.• We did this so that we can better understand

specialized cells.• A zygote is the cell created immediately after

fertilization. This cell is the generalized cell that will multiply & divide AND specialize along the way of development.

• The “partly generalized” cells left in you are called “Adult” or “Tissue” stem cells

• We will play a game that models the idea of differentiation

Differentiation Stem Cell Game• ‘Start as a stem cell!’ was designed to:

– introduce people to the idea that cells differentiate to produce mature cells

– that differentiation pathways are controlled by signals within and outside the cell

– that stem cells are at the start of these pathways.

• The blood system has been chosen as the model for this game, as out of all the systems in the human body this is the most well characterized.

Goal: To create as many mature cells as you can in 5 minutes. 1. One player places their puffball on the central blood stem cell (green one)

and the five minute countdown is started. 2. The player throws the three dice together to display a three color

combination. The player moves in the direction of the colors shown. If a direction shows a multi colored arrow then all of those colors are needed to go in that direction.

3.Once the first player has moved, a second puts their puffball on the central blood stem cell and throws the dice, moving in the direction the color combination allows. Any player on the board can move when the dice is thrown whether or not they threw the dice.

4.When a player reaches a mature cell (they can’t differentiate any further) they place a tick on the game results board next to the image of that mature cell and place their counter back on the central stem cell.

5.If a player ‘self renews’ by throwing a blue, pink and yellow when on the central stem cell, they can place two ticks on the game results board next to the mature cell they next become.

6.Once the five minutes are over count the number of mature cells produced. The winner is the group with the most mature cells.

• Write down 2 new things you know from this game.

What the game conveys… (notes I’ll post) 1.Stem cells are able to produce copies of themselves (self

renew) and give rise to different cells . 2.That different cells produced are increasingly more

restricted in the types of cells they can give rise to. 3.At the end of the pathway a mature cell is formed that

cannot divide to give rise to different cells. 4.The type of cell produced and when this happens

depends on the signals that a cell receives from its environment (both internal and external).

5.The types of mature cells produced from blood stem cells. NOTE: Scientists are manipulating cell environments in the

lab to go backwards along these signal pathways! IPS cells!!!

homework

• Differentiation worksheet