1. Stem Cells and Regenerative Medicine
I work for the California Institute for Regenerative Medicine, a state government agency that funds stem cell research. We don’t actually do the research, but we decide what scientific projects in California are worth spending money on and make sure that researchers are using the money in a way that will lead to stem cell cures for the people of California. Our agency’s mission is to “turn stem cells into cures”.
Zach Scheiner, PhD
Science Officer

2. What are stem cells? What are the different types of stem cells?
Why should we study stem cells? What potential therapies could they provide?
What are some of the challenges facing stem cell research?
These are the questions I’d like to answer in this talk. Does anyone know what a stem cell is? Does anyone have any ideas about why we should study them?

3. All Stem Cells Can… 1. Self-Renew 2. Differentiate
What does self-renew mean?
What does differentiate mean?

4. Self-Renewal (symmetric cell division)
A lot of cells in your body self-renew, for example your skin. What’s the technical term for this that you guys probably learned in biology? Mitosis.

5. Differentiation (asymmetric cell division)
Progenitor cell
At some point in embryonic development, stem cells undergo an asymmetric type of cell division. When the stem cell divides, it gives rise to two cells that are different from each other.
OK so what makes a stem cell unique? (wait for answers) FIRST: it self-renews SECOND: it maintains its own population.
Stem cell
Stem cell

6. Neural Progenitor Cell
Skin Cell
Neuron (Brain Cell)
Skin Progenitor Cell
Neural Progenitor Cell
Not all stem cells can do this! Differentiate into both skin and brain. Some can only differentiate into brain, or only skin, or only blood. These shown here are a special type of stem cell… do you know what type? Embryonic.
Embryonic
Stem Cell

7. Stem Cell Types Embryonic – pluripotent: can form
almost any cell type in the human body
Tissue-Specific (Adult) –
multipotent: can form only limited
types of cells (blood, brain, liver, etc.)
Induced Pluripotent – engineered
by scientists to act like embryonic stem cells
There are a lot of misunderstandings about embryonic stem cells, so I’m going spent a few minutes talking about them.
Does anyone know where embryonic stem cells come from?

8. In Vitro Fertilization
Conception in a Dish
Normally, when a couple has sex to make a baby, sperm meets egg in the fallopian tube and fertilization occurs. But sometimes, a couple can’t have a baby naturally. Do you know what type of clinic they might go to if they have this problem? The couple would go to an in vitro fertilization clinic.
A fertility doctor would use hormones to make the woman produce between 10 and 30 eggs. These are removed from the woman’s body. The man gives his sperm, and one sperm is sucked up. On the left, a glass tube holds the egg in place.
Do you see how much bigger the egg is than the sperm? What’s amazing is they both contribute the same amount of DNA to the developing embryo.

9. In Vitro Fertilization
Day 1
The sperm, which contains the man’s half of the DNA, is injected into the egg, containing the woman’s half of the genes. This is day 1 of fertilization.

10. In Vitro Development Day 1
At 12 hours after fertilization you can see the two bundles of genetic material called pronuclei. These contain the DNA from each parent. By hours after fertilization, these bundles fuse and combine genetic material from mom and dad.
What starts out as two cells becomes one cell, called the fertilized egg.

11. In Vitro Development Day 2
On day 2, that one cell has divided into two cells. How do you guys think these cells are related? (wait for answers) That one cell made a copy of itself, so they are identical.

12. In Vitro Development Day 2
Later on day 2, each of those two cells divides, making four identical cells.

13. In Vitro Development Day 3
By day 3, each of those four cells divides, making eight identical cells. Each cell is one-eighth the size of the original fertilized egg.

14. In Vitro Development Day 4
On day 4, the cells have divided several times more and you can’t tell one cell from another cell.

15. In Vitro Development Day 5 Embryonic Stem Cells
Day 5 is a big day. This is the day that fertility doctors generally implant the embryo into the woman’s uterus. At this stage the embryo is called a blastocyst, and it’s the first stage in which cells are specialized. The outer layer has cells that will become the placenta. There is a clump of cells sitting inside that will become the embryo and later, the fetus. This is also the stage where embryonic stem cells can be isolated. CLICK
This process of in vitro fertilization isn’t easy. Doctors will often have to implant many blastocysts before pregnancy occurs. So the doctor starts with fertilized eggs, but only implants 2-3 at a time. So this means there are a large number of leftover embryos. After the doctor has chosen a few blastocysts to implant, what do you think happens to them? (wait for answers) The leftover embryos are frozen.
USE AGAIN: These can later be used by the couple to have more kids.
ADOPTION: They can be donated to another couple for adoption, and these successful pregnancies are called “snowflake babies.”
STEM CELL RESEARCH: They can also be used to make stem cells. In the US right now, there are about 400,000 embryos leftover from this procedure. These could be used for research. A scientist would harvest the clump of embryonic stem cells and plate it onto a petri dish to make an embryonic stem cell line. But many people have a problem with this because you need to destroy these embryos and any chance they had to grow into babies.

16. Totipotent Pluripotent Multi- potent
This cell can form all of the
cells in the human body
Pluripotent
This cell can form
almost every cell type
in the human body
Multi-
potent
This diagram will eventually show the entire range of development, from fertilized egg to mature cell types in the body.
Each cell in the 8-cell embryo, here in red, can generate every cell in the body including the placenta and extra-embryonic tissues. These cells are called TOTIPOTENT stem cells. Why are they called totipotent? (wait for answers) Because one red cell can potentially make the TOTAL human being.
The embryonic stem cells inside the blastocyst, here in purple, can generate every cell in the body except placenta and extra-embryonic tissues. These are called CLICK! PLURIPOTENT stem cells that can differentiate into all the 200+ cell types in the body, but they cannot form the entire human being. CLICK! Pluripotent stem cells can be isolated and grown in culture, or left to develop into more specialized cells in the body.
CLICK! Adult stem cells or tissue-specific stem cells have restricted lineages. Adult stem cells show up when the three distinct layers form in the 14-day-old embryo, and are present in the fetus, baby, child, and so forth. Adult just means they’ve gone further down their lineage pathway than the initial stem cells in the embryo. They are called CLICK! MULTIPOTENT stem cells and will only become mature cells from the tissue in which they reside. Adult stem cells are present throughout your life and replace fully mature CLICK!, yet damaged and dying cells.
Fully mature

17. Human embryonic stem cells in culture
There are THOUSANDS of HUMAN embryonic stem cells growing in this circular colony. The HUMAN embryonic stem cells are grown on top of MOUSE feeder cells—the longer cells—which provide essential nutrients.

18. Fluorescent imaging of human embryonic stem cell colonies
Scientists can label embryonic stem cells using glowing molecules. (LEFT) On the left, the smaller blue dots in the green area—a single colony—label the nuclei of the embryonic stem cells, and the blue dots outside the colony label feeder cells.
(RIGHT) On the right is a zoomed out version of the picture on the left, showing embryonic stem cell colonies. Embryonic stem cells like to grow in little colonies spaced out over the dish instead of in one big layer.

19. What Diseases Do Stem Cells Treat? Have the Potential to Treat?
Currently Treat
Blood Diseases (including immune system disorders)
Genetic metabolic disorders (very limited/experimental)
Tissue/organ replacement (very limited/experimental)
Currently Treat
Blood Diseases (including immune system disorders)
Genetic metabolic disorders (very limited/experimental)
Tissue/organ replacement (very limited/experimental)
Potential to Treat
Heart Disease
Neurological Diseases (Parkinson’s, Alzheimer’s, Huntington’s & others)
Stroke
Type 1 Diabetes
Macular Degeneration (a common cause of blindness)
Cancer
HIV/AIDS
Spinal Cord Injury
Multiple Sclerosis
ALS (Lou Gehrig’s Disease)
Liver Disease
Potential to Treat
Heart Disease
Neurological Diseases (Parkinson’s, Alzheimer’s, Huntington’s & others)
Stroke
Type 1 Diabetes
Macular Degeneration (a common cause of blindness)
Cancer
HIV/AIDS
Spinal Cord Injury
Multiple Sclerosis
ALS (Lou Gehrig’s Disease)
Liver Disease
…and more!
Blood diseases include leukemias, immune deficiencies, sickle-cell anemia and others.
More… liver disease, wound healing, spinal muscular atrophy, etc., etc.
I will talk about these diseases in yellow.

20. Bone Marrow (Hematopoietic Stem Cell) Transplant Example of a tissue-specific stem cell therapy
Hematopoietic stem cell transplants are the most common type of adult stem cell treatment. Does anyone know what a hematopoietic stem cell is? What types of diseases are these transplants used to treat? This schematic describes a bone marrow transplant, which have been used for 40 years as a treatment for diseases and cancers of the blood.
FIRST, a donor’s tissue type is matched with the patient’s tissue type to make sure the patient won’t reject the transplant. This is why close relatives are often used for bone marrow transplants. NEXT, bone marrow containing hematopoietic stem cells, or blood-forming cells, is taken from the donor’s pelvis. THEN, right before the transplant, the recipient patient receives chemotherapy to destroy all of their malignant blood cells. FINALLY, the donor’s marrow is filtered to increase the ratio of stem cells and then given in a transfusion to the patient. The stem cells will find their way to the bone marrow and eventually repopulate the patient’s blood system.

21. Click on Picture to Play Video
Trachea transplantation Example of tissue-specific stem cell-based tissue replacement
Does anyone know what a trachea is? Another way we can use stem cells is to grow them into replacement organs. She didn’t need drugs to suppress the immune system because the cells came from her own body!
So these are examples of two ADULT stem cell therapies. A lot of people say, if adult stem cells can do so much, why do we need to do research on embryonic stem cells?
Click on Picture to Play Video

22. Tissue-specific (adult) stem cells are powerful and promising!
Why do researchers study embryonic stem cells?
Tissue-specific stem cells are limited in their differentiation potential (blood  blood)
Stem cells from some tissues are inaccessible
Some tissue-specific stem cells don’t self-renew well
Some tissues may not have stem cells!

23. Embryonic Stem-Cell Derived Heart Muscle Cells
In these movies you’ll see heart muscle cells that researchers created from embryonic stem cells. These cells are from a mouse, but researchers have also made them from human embryonic stem cells. So in this case, researchers isolated embryonic stem cells from mouse blastocysts, grew them in culture, and then gave them proteins and growth factors that caused them to differentiate into heart muscle. And what you’ll see is really cool. (Start movies.)
What could these be used for?
Cell replacement after heart attack (more obvious answer)
Drug screening! (try to get them to come up with it… what if you had a new drug to treat cancer but you’re worried that it might not be safe? Particularly that it might not be safe for the heart?)
Click on Pictures to Play Videos

24. Applications for Embryonic Stem Cells Video: Diabetes A CIRM Disease Team Video: Age-Related Macular Degeneration (AMD) A CIRM Disease Team
The next two slides contain video about therapies that are being developed from embryonic stem cells. Note that embryonic stem cells cannot be transplanted “as-is” for therapies. If you inject embryonic stem cells into a patient, those cells often turn into nasty tumors called teratomas. Teratomas contain many differentiated tissues because the extracellular environment has given them abnormal differentiation instructions. In order to be used for therapies, embryonic stem cells must first be coaxed to differentiate into adult stem cells, progenitor cells, or fully mature cells.

25. Video: CIRM Disease Team for Type 1 Diabetes
Insert Diabetes video here if desired.

26. Video: CIRM Disease Team for Age-Related Macular Degeneration (AMD) – Eye Disease
Insert AMD video here if desired.

27. What are some of the challenges facing embryonic stem cell research?
Differentiation of stem cells into
mature, functional cells
Potential for tumor formation
Immune rejection
So while the potential of stem cell research is incredibly exciting, there are some challenges for the field before it’s widely used to treat and cure disease. These aren’t the only challenges but they’re 3 major ones:
Differentiation – it takes the cells in your body, weeks or months (or even years) to develop into the functional cells you have in your body today – researchers need to figure out how to replicate that process in a dish – some successes already, but plenty of work left
Potential for tumor formation – I haven’t really discussed this, but in many ways, ESCs resemble tumor cells because of their ability to divide rapidly and endlessly. In fact, if you transplant human embryonic stem cells into mice, you get benign tumors called teratomas! It will be crucial that scientists find ways to transplant pure populations of differentiated cells, with no contaminating pluripotent cells, when moving stem cell therapies into humans.
Immune rejection – we talked about this with the bone marrow transplant and trachea treatments – cells not only need to be mature and functional, but they need to survive after transplantation! Immunosuppressant drugs are tough on the body and leave it susceptible to infection. iPS cells may be an answer?
These challenges are why we need students like you to pursue stem cell research!

28. Induced Pluripotent Stem (iPS) Cells Genetically engineering new stem cells
Virus engineered
to express four
key “pluripotency”
genes 
Pros: No embryos required
No immune rejection?
Disease in a dish?
Cons: May not be = to ESCs
Genetically engineered
Four years ago, Shinya Yamanaka, a Japanese scientist who trained and worked at the Gladstone Institute at UC San Francisco, made a breakthrough discovery and showed that adult skin cells could be REPROGRAMMED (using genes encoded by viruses) into cells that resemble embryonic stem cells.
In induced Pluripotent Stem Cell technology, you FIRST isolate and culture skin cells from a patient. SECOND, you introduce three or four pluripotency genes into the skin cells by using an engineered virus carrier. THE EXPRESSION OF THESE GENES REGENERATES THE STEM CELL PHENOTYPE. The viruses simply deliver the genes of interest and are themselves engineered not to be harmful.
The advantages are that the induced Pluripotent Stem cells would be genetically identical to the person who donated the skin cells, so any cells derived from these iPS cells would not be rejected by the patient’s immune system as with clone-derived cells. So ultimately, this would be a move toward personalized, cell-based therapies.
For now, these cells are perfect for making and studying diseases in a dish to promote basic research. But many important details need to be worked out before this tool is used as an actual technology in the clinic to treat patients.
Skin cells
iPS cells

29. Video: Parkinson’s“disease-in-a-dish”
Insert Parkinson’s disease video here if desired.

30. www.cirm.ca.gov Acknowledgements Todd Dubnicoff Amy Adams
Laurel Barchas
Finally I’d like to return to this quotation from Roman Reed, who is my age and was paralyzed playing football in 1994 and has worked tirelessly to promote funding of stem cell research for spinal cord injury. This quotation, “Turning stem cells into cures” is the mission of CIRM and the reason we get up every morning excited to go to work.
I’d also like to thank Laurel Barchas, a graduate student at UC Berkeley, who put together many of the slides I used today. She’s a part of the Stem Cell Education Outreach Program (SCEOP) at UC Berkeley. The Stem Cell Education Outreach Program is part of a larger movement in and by our state (the California Stem Cell Education Initiative) to incorporate stem cell topics into high school science classes. Their goal is to work with high school students and teachers to develop a curriculum on stem cells that is taught throughout California. (Stem Cell Awareness Day is 10/5.)
I’d really like to encourage you to go to our website when you get a chance. We have educational resources and lots of videos featuring interviews with prominent CA stem cell scientists.

31. Extra Slides
So I’m going to show a video about a CIRM grant that is pursuing the “disease-in-a-dish” approach for Parkinson’s Disease.

32. Neural stem cells for drug delivery Focused delivery of chemotherapy for cancer
Day 0
Day 7
Day 14
NSCs injected
(no tumor)
In addition to cell-based therapies, stem cells could instead be used to deliver medicine. Some neural stem cells seem to migrate to diseased and cancerous regions. In these slides, you see mice whose brains have been injected with neural stem cells. In the control mouse without the tumor, the neural stem cells normally stay near the injection site. However, neural stem cells when injected into mice with brain cancer actually migrate to the tumor, the dotted white circle. If the neural stem cells were engineered to produce or deliver an anti-cancer drug, they could greatly increase the drug’s effectiveness.
(This approach could be particularly relevant for brain disorders because the blood-brain barrier excludes more than 70 percent of all drugs. So neural stem cells can be harvested from a patient’s brain, coaxed to proliferate outside of the body, be genetically engineered, and then re-implanted to deliver a drug that normally can’t pass through the blood-brain barrier.)
NSCs injected (tumor)
Shah et al. Dev Neurosci 2004

33. Stem cells for drug delivery Focused delivery of chemotherapy for cancer Another CIRM Disease Team
Genetically Engineered
Neural Stem Cells
Mice are given a non-toxic drug, which the neural stem cells can convert to an active drug to shrink tumors!
This diagram shows a very similar experiment done in mice, but in this case with tumors dispersed in the body and with genetically engineered neural stem cells. These cells were engineered to express an enzyme that can convert a harmless drug to a toxic, chemotherapeutic drug. As I mentioned before, neural stem cells seem to migrate towards tumors and disease, so even when you inject them into the mouse’s tail vein, they migrate to the tumor. Then if you inject the mouse with a harmless drug (green) the neural stem cells convert it to a toxic drug that shrinks the tumors! In fact these researchers at City of Hope hospital in LA can cure these cancers in mice! They have submitted an application to the FDA to try the same approach in humans (but not using the tail vein).
This is very cool but a little complicated, ask if there are any questions before moving on.

34. Milestones in Embryonic Development
Days 7-14: Embryo implants in the uterus
Day 14: Three distinct layers begin to form (no more embryonic stem cells)
Days 14-21: Beginning of future nervous system
Days 21-24: Beginning of future head, neck, mouth, and nose
Weeks 3-8: Beginning of organ formation
Week 8: Embryo is called a fetus
The primitive heart starts beating in week 4.
By week 8, many human features are recognizable and the embryo is called a fetus.
Remember, embryonic stem cells used for research are harvested from 5-14 day old embryos, WAY before organ formation starts. The donors ALWAYS have to give their permission to use embryos for research.
Image is a 5-week old embryo from an ectopic pregnancy.