Stem Cells

Part 2

Review:• As an organism develops, cells go from

being all alike to forming the many different types of tissues (differentiation).

• A cell that has become a special type may be able to divide to make more of the same type, but cannot make different types.

Stem cells can renew and can differentiate

http://www.biocell.com.au/images/common/self-renewal.png

Stem Cells - Types

• Stem cells have the potential to make new cell types (they are potent)

• Types:– Totipotent – (toti-, entire) can form any cell type.

The first few cell divisions after fertilization.– Pluripotent – (pluri-, many) can form nearly any

cell type. Pluripotent stem cells from the early embryo can form anything except the placenta.

Stem Cells - Types

• Multipotent – can form closely related cell types, such as blood cells.

http://www.lifeethics.org/www.lifeethics.org/uploaded_images/Hematopoietic-Stem-Cells-10-07-779860.JPG

Where do we getstem cells?

• From early embryos.• From umbilical cord blood.• Created from adult cells.

Stem cell researcher Douglas Melton (Harvard University):

“If I were in high school, I can’t imagine anything more interesting than stem cells…This is so cool. It’s so amazing that cells in the body have this potential that we can now unlock by asking question after question.”

Applications

NeuronMuscle

cell

Pancreatic Islet

Petri DishStem Cells

Different chemicals / molecules are added to the stem cells to make them become specific types of cells.

Growth factors Chemical cues

http://learn.genetics.utah.edu/content/tech/stemcells/scresearch/

The vision for UCI’s Stem Cell Center: Stem cell therapies for neurological disorders

• Brain and spinal cord injury.

• Stroke.

• Neurodegenerative diseases– Parkinson’s Disease– Huntington’s Disease– Alzheimer’s Disease– Multiple Sclerosis– Lou Gerhig’s Disease (ALS)

Reeve-Irvine Research Center

Blastocyst -

Stem Cells

Pipette

Stem Cells“Blueprint” cells

Stem Cells

Petri Dish

“Blueprint” cells

Goal #1: to make stem cells into nerve cells

The stem cells are treated with factors to cause them to

differentiate into particular cell types Stem cells differentiated into neurons

Reeve-Irvine Research Center

http://abcnews.go.com/Technology/wireStory?id=6713062

http://php.louisville.edu/news/news.php?news=1343

Question of safety: do these cells have the potential to form tumors over longer periods of time?

Embryonic Stem Cells: When Will We Be Using Them?

Predictions from one biotechnology expert (The Scientist, Feb. 2009):

• Research into discovering new drugs – now• Personalized medicine – soon. (Using stem cells

from a patient, will be able to test particular drugs before giving to the patient.)

• Treatments – we are still decades away.

Pipette

Pipette

Stem Cells

Petri Dish

Human Embryonic Stem Cells

To remove the stem cells, the Blastocyst is broken open and the stem cells removed with

a pipette(an ultra thin glass tube)

The stem cells are placed in a

dish and are fed and cared for

(each blastocyst = 1 stem cell line)

Blastocyst -from In Vitro Fertilization Clinic

Stem Cells “Blueprint” cells

A Blastocyst is a hollow ball of cells with a small clump of stem cells inside

Stem Cells

“Blueprint” cells

Human EmbryonicStem Cells

• Destruction of embryos raises ethical issues.

• Would be simpler if we could change adult stem cells to make them pluripotent (reprogram them).

Stem cells from adult cells• Adult stem cells are usually

multipotent rather than pluripotent.• To get pluripotent stem cells from

adult cells, chemical and genetic tricks must be used.

• Called induced pluripotent stem cells (iPS).

Stem cells from adult cells

Time, Feb. 9, 2009

Stem cells from adult cells (induced pluripotent stem cells)

• In the original method, four genes were inserted, using viruses as vectors.

• Now the method has been made safer by using chemical treatments instead of two of the four genes.

• Safer vectors are also now being used.

Stem Cells in the News• In 2001, President Bush ordered an end to

funding of research on embryonic stem cells.• Researchers using federal money could only

work on cell lines already being used.• Most of these proved not very useful.• Research continued with private or state

money, or in other countries.• President Obama will probably reverse the

Bush policy.

http://www.reuters.com/

http://www.chicagotribune.com/