Stem Cell Powerpoint with teacher notes [Compatibility Mode]

Stem Cells

Many breeds of large dogs are affected by hip

dysplasia. This degenerative disease affects their

hind legs, hindering mobility. Watch as scientists at

Vet-Stem explain how stem cells are used as a cure

for these animals.

Clip 1: Hip dysplasia

Clip 2: Vet-Stem’s Dr. Harman

The video clip of the German Shepherd raises

many questions. Imagine if Dr. Bob Harman,

the lead scientist at Vet Stem, were to come to

class for a discussion. What kind of questions

would you ask him?

– What is a stem cell?

– Can this be done in humans?

• What other questions do you have?

What are stem cells?

• Stem cells can

indefinitely divide and

give rise to a variety of

other cell types.

• One example is the

hematopoietic stem cell

which gives rise to all

blood cells in the body.

Two types of stem cells

• Embryonic stem cells

are pluripotent and can

give rise to all types of

cells in the body

• Adult stem cells are

only multipotent and

are more limited in the

types of cells that they

can give rise to.

• Totipotency – the ability to produce any type

of cell. Ex: zygote (embryo + placenta)

• Pluripotency – the ability to produce any cell

lineage. Ex: can differentiate into germ layers

• Multipotency- the ability to produce any kind

of cell within a cell lineage. Ex: blood stem cell

• Unipotency- the ability to produce only one

kind of cell. Ex: hepatocytes (liver cells)

http://images.chron.com/blogs/realrehab/archives/pictures/Embryo%20Zygote.jpg

http://images.chron.com/blogs/realrehab/archives/pictures

/Embryo%20Morula.jpg

Differentiation Events

• Embryonic stem cells enter the first differentiation event at the 8 cell morulastage.

• Each of these totipotent cells express two genes Cdx2 and Oct 3/4.

• At the morula stage the innermost cells no longer express the Cdx2 gene.

• This loss of gene expression due to position is the differentiation event.

http://newsimg.bbc.co.uk/media/images/44651000/jpg/_4

4651459_blastocyst_cred226.jpg

Differentiation

• As these pluripotentcells divide they continue to be affected by their changing position.

• This changing position and resulting change in environment will result in other differentiation events.

• Three stem cell lines

Three Germ Layers

(three stem cell lines)

• As gastrulation occurs, three layers of pluripotent stem cells are created.

– Ectoderm- gives rise to skin and nervous system

– Mesoderm- gives rise to blood, bone, and muscle

– Endoderm- gives rise to gut and lungs

http://www.tvdsb.on.ca/saunders/courses/Onli

ne/SNC1D/Vejvoda/biology/human-

conception5.jpg

http://www.biology.iupui.edu/biocourses/N100/images/38g

astrulation.gif

http://www.cryoviva.com/image/new-

stemcells.jpg

Differentiation con’t

• As cells differentiate, they lose some of their

ability to become all types of cells.

• These multipotent stem cells develop from the

three germ layers during gastrulation.

Mesenchymal stem cells

http://stemcelldoc.files.wordpress.com/2009/02/msc-srtem-

cell3.jpg

The stem cell blog

Skin derived precursor cells. (photo courtesy Freda

Miller)

A stem cell emerging from rat bone marrow. By stimulating the release of stem cells after a

heart attack, the healing process could be accelerated. Photograph: Imperial College London

Stem Cell: Paul Leonard/Photo

Researchers

Unipotent Cells

• As multipotent cells divide creating either new

stem cells or a specialized (unipotent) cell.

• These specialized cells have a variety of

characteristics that suit their role in the body.

A scanning electron microscope image of normal human blood.

Photo by Bruce Wetzel, courtesy of the National Cancer Institute

http://www.fi.edu/learn/heart/blood/images/red-

blood-cells.jpg

http://people.eku.edu/ritchisong/301images/Red_W

hite_Blood_cells.jpg

Scanning electron microscope image of a mammal's lung. Image by Dartmouth Electron Microscope Facility

http://www.sciencemuseum.org.uk/a

ntenna/musclemachines/images/cells.

jpg

© Dennis Kunkel

Research by Stelios Andreadis has produced this smooth

muscle progenitor cell derived from a hair follicle, which

expresses calponin (in red), a marker for smooth muscle

cells. The cell nucleus is shown in blue. (Credit: Image

courtesy of University at Buffalo) – Science Daily.com)

http://www.nist.gov/public_affairs/

images/06MSEL011_BoneCementCe

llsAttachP_HR.jpg

Liver Cells:

http://www.connexin.net/microscopy-fluorescence-confocal-LSM-gallery.html

Brain Cells:

http://www.connexin.net/microscopy-fluorescence-

confocal-LSM-gallery.html

Nerve Cell:

http://www.wellcome.ac.uk/en/bia/images/25.jpg

http://www.physorg.com/newman/gfx/ne

ws/2006/neuroligin_1.jpg

Stem Cell Mysteries

• There are several questions that need to be

answered through stem cells research

– How can stem cells remain unspecialized and

self renewing for many years?

– What are the signals that cause stem cells to

become specialized cells?

– Can we make multipotent stem cells revert to

pluripotency?

Curing Diseases

• How can stem cells help to cure disease?

• Consider the video clip you watched at the

beginning of the presentation, now imagine

someone whose knee has degenerated.

Explain how stem cells could be used as a

cure.

Cancer Stem Cell:

http://www.urmc.rochester.e

du/news/story/uploadedimag

es/cancer%20stem%20cellUC

LA3.jpg

Curing Injuries

• Spinal Cord Injuries

– There are currently between 250,000 - 400,000

Americans living with a spinal cord injury. More

than 13,000 additional people are injured each

year.

– Every 41 minutes another person sustains a spinal

cord injury

– More than half of those injured are between the

ages of 16-30

http://www.travisroyfoundation.org/pages/resources-

stats.htm