Wave - ONLINE EDITION
The University of Manitoba is poised to become a leader in stem cell research
Dr. Afshin Raouf walks into one of the labs located in the Basic Medical Sciences Building at the University of Manitoba's Faculty of Medicine and checks out a petri dish that has been placed under the lens of an Evos microscope.
Suddenly, a series of clear grey blotches - like water drops on a pane of glass - appear on a monitor. Raouf fiddles with a dial on the machine until the image comes into focus and then steps back, letting an observer come in for a closer look.
"What you are seeing are live cultures of stem cells," says Raouf, Assistant Professor of Biochemistry & Medical Genetics and Immunology at the U of M's Faculty of Medicine.
As he explains, the batch in question was collected four days ago. "Left on their own, these cells will divide every 24 hours, eventually growing to form human breast tissue," he says. That is to say, if these cells were injected into a mouse, they would eventually form all the structures of a fully functional mammary gland.
But these stem cells were not left untouched. Once they were collected, Raouf and his team set out to manipulate them by adding or subtracting certain genes. During the next few weeks, they will continue to monitor the stem cells, looking for any differences that might provide insight into how breast cells develop.
Ultimately, Raouf hopes to identify changes in breast cell development that signal the start of breast cancer. In doing so, he hopes to gain some insight into workings of cells that could pave the way for new treatments for breast cancer, or perhaps even stop the disease before it gets started.
"That is a lofty goal," admits Raouf. "But if you don't dream, you're obsolete."
Of course, Raouf is not the only one with big dreams in this laboratory. He is one of six principal investigators working in the Regenerative Medicine Program at the University of Manitoba's Faculty of Medicine. Each one of these scientists is a topflight researcher in their own right, and each one is dreaming of new ways to use the power of stem cells to help treat or cure a number of diseases and conditions, including cancer, Rett Syndrome, and spinal cord injuries.
Indeed, even the lab they work in is a kind of dream come true.
The development of the program - the first of its kind in Western Canada - is the brainchild of Dr. Geoff Hicks, Associate Professor of Biochemistry & Medical Genetics and Physiology. A graduate of the University of Manitoba, Hicks has spent two decades researching stem cells, racking up some impressive achievements along the way.
In 1991, he was the first to molecularly clone the so-called wild type p53 gene, and published one of the first papers to show that the gene was actually helpful in suppressing cancer cell growth. Previously, it had been believed that p53 was a cancer-causing gene.
While doing his post-doctorate work at the famed Massachusetts Institute of Technology, Hicks published a new approach for identifying genes that keep cancer at bay that fundamentally changed the way genome research projects were done.
"Until then," Hicks says, "all genome-wide approaches were driven by phenotype (identifying mutations of interest based on a recognizable physical change in the cell or organism and then finding the gene responsible and cloning it). The problem with the phenotype approach is that you know there is a gene, but you have to go through all 23,000 of them to find the one that is responsible. My approach was to skip the needle in a haystack strategy and go straight to sequencing to identify all the genes up front. In other words, rather than looking at each gene one at a time, to go after all possible genes at the same time. This was the beginning of modern functional genomics and the basis of almost all major genomics projects that followed."
Hicks returned to Manitoba in 1998 with a dream of one day heading a major stem cell research centre. In 2008, he and several faculty members, including Faculty of Medicine department heads Drs. Louise Simard (Biochemistry & Medical Genetics), Janice Dodd (Physiology), and Tom Klonisch (Human Anatomy and Cell Science), pitched this idea to the Dean of the Faculty of Medicine. That led to a $500,000 start-up grant as well as support for six faculty members. But that was just the beginning. In the four years since, Hicks has raised an additional $8.5 million - enough to turn the dream into reality.
Although it was established in 2008, the Regenerative Medicine Program is just hitting its stride as it moves into a new 24,000-square-foot laboratory, which will be officially launched this fall.
So far, the University of Manitoba dream team consists of Hicks and Raouf, as well as Drs. Donna Wall (Professor, Pediatrics & Immunology), Soheila Karimi (Assistant Professor, Physiology), Mojgan Rastegar (Assistant Professor, Immunology and Biochemistry & Medical Genetics), and Tamra Werbowetski-Ogilvie (Assistant Professor, Biochemistry & Medical Genetics). Hicks is looking for two more scientists to fill the roster. Once everyone is in place, the program will include eight principal investigators, 36 graduate students, 20 technologists and 10 post-doctoral fellows. Ultimately, it will have about 120 people on staff.
The objective for the program is fairly straightforward. "We want to build a core of expertise in stem cell biology," Hicks says. Having a critical mass of researchers in Winnipeg in one central facility will fuel advancements in research and ultimately stem cell therapies for patients much faster, he says. "I believe major breakthroughs are possible and that we can have the most profound effect on people's lives."
The program's open-concept lab is designed to promote collaboration by integrating expertise from different areas in one space. Research teams work sideby- side, creating an opportunity for a free exchange of ideas and innovative problem-solving. "That's where the big breakthroughs come," Hicks says.
Stem cells have emerged as a kind of Holy Grail of medicine in recent years because of their unique characteristics. They begin to form in the early stages of development and essentially serve as the building blocks for the body and all of its organs and tissue. As a result, they have the ability to replace, restore or repair damaged or diseased cells.
There are three types of stem cells - adult, embryonic and induced pluripotent cells (iPS).
Adult stem cells are derived from the donor tissue or organ. Also known as tissue-specific or somatic stem cells, these molecular marvels work their magic every day by replenishing the cells that form skin tissue or blood.
Embryonic stem cells differ from adult stem cells in terms of where they come from and what they do. While an adult stem cell can be derived from a person's skin or blood, embryonic stem cells are taken from blastocysts, which are tiny groups of cells formed in the early stages of development. They also differ from adult stem cells in that they can "differentiate" or transform themselves into the cells of any organ or tissue in the body.
Induced pluripotent stem cells, meanwhile, are relatively new to the scene, having been discovered in 2007 by a Japanese scientist. Essentially, they are adult stem cells that have been reprogrammed to have many of the characteristics of embryonic stem cells.
While all three types of stem cells have tremendous potential as regenerative therapies, scientists are generally most enthusiastic about embryonic and iPS stem cells because they have a broader application than adult stem cells.
With all the talk about the potential of stem cells, it is sometimes easy to forget that their inherent regenerative powers are already used to address a number of afflictions. The bone marrow transplant is a case in point. In this procedure, adult blood stem cells in bone marrow are taken from a donor and injected into a patient whose bone marrow is damaged by a disease, such as cancer. The healthy adult stem cells essentially regenerate the bone marrow cells of the patient and will repopulate an entire new blood system for the rest of that patient's life.
The existence of stem cells was first "inferred" by scientists in 1860 through the analysis of embryo development and microscopy of bone marrow. "It was proposed that such a cell must exist," explains Hicks, "because we all come from a single cell, so scientists theorized that there must be cells that have that kind of capacity or that kind of potential."
But it wasn't until 1961 that the Canadian team of Drs. James Till and Earnest McCulloch was able to show that stem cells do in fact exist. "They are the people who first showed that there was a stem cell," says Hicks.
Specifically, the two Canadians identified what are known as haematopoietic (blood) stem cells, the kind found in bone marrow. "In their experiments, they showed that there are haematopoietic stem cells, and if you transferred these cells (as in a bone marrow transplant), they were able to repopulate multiple blood cell types. The key is that single cells could form multiple blood cell lineages when transferred," says Hicks. That discovery, he says, marked the beginning of modern stem cell biology.
Another major breakthrough occurred in 1981 when scientists discovered how to extract embryonic stem cells from the embryo of a mouse. By 1998, scientists had determined how to derive stem cells from the blastocysts of human embryos, created through in-vitro fertilization.
"The embryonic stem cell is really the ‘Grand Poobah,' says Hicks. "That's the one that can form every single cell type of the body."
While the science involved in extracting embryonic stem cells is obviously complicated, the concept for doing so is relatively straightforward. It all starts with the process of in-vitro fertilization - the act of fertilizing eggs outside the human body. This procedure results in the production of a large number of blastocysts - tiny biological containers each carrying about 200 cells. Some - usually two or three - are implanted in a woman's womb and progress to become viable embryos. But most blastocysts created though invitro fertilization are not used and cannot progress to a viable embryo outside the womb on their own.
As Hicks explains, "While it's true that blastocyst embryos can form viable embryos when implanted (in the womb), embryonic stem cells themselves are "pluripotent," meaning they retain the ability to form all the cells of the human body, but not the extra-embyronic tissues of a blastocyst embryo that are required to produce a viable embryo."
It is from these surplus blastocysts that scientists are able to extract the embryonic stem cells that hold so much promise for changing the very nature of medicine.
An important point, says Hicks, is that these stem cells can maintain themselves forever, which means the same stem cell lines can be used continuously for research.
Once scientists figured out how to derive embryonic stem cells, the whole field of stem cell research opened up because researchers could now test their hypotheses on something other than mice, Hicks says. While stem cell research on rodents is the most comparable to humans, it's still not perfect because, simply put, rodents aren't people. "There can be critical differences at the molecular level," he says. "And it's the small differences that can make or break it, so it is important to validate discoveries in human cells."
Given the potential for stem cells to change the nature of medicine, it is easy to understand why scientists are so intrigued. The big question, says Hicks, is how do we get these stem cells to form the right adult cell types for disease treatment?
In the Winnipeg lab, research can be roughly broken down into three categories:
- Investigating how stem cells function and whether they can be reprogrammed to stop certain diseases, such as cancer, from developing.
- Determining how embryonic stem cells can be manipulated into becoming an organ or a tissue that can be used to replace or regenerate an ailing organ or tissue in a patient.
- Using adult stem cells from a specific organ or tissue to regenerate organs or tissue in a patient.
Raouf, for example, is investigating how adult stem cells function by introducing or withholding certain genes at specific points of their growth cycle. In doing so, he hopes to determine whether the actions cause any change in the development of the cell.
He uses the example of couriers delivering packages to explain the process. In any city, couriers deliver packages at all times of the day, and each one must follow the laws of the road as they navigate their way from one end of the city to the other.
Likewise, signal pathways deliver messages in a cell. But where are they going and what information do these messages contain? That's the question researchers are trying to answer, says Raouf.
"So what we do is slowly, methodically disable the signal pathways and see what happens to the cell. Can it function? If it doesn't, then we know that the signalling pathway in question plays an important role in the operation of the cell. The other way to do it is to (manipulate) the signalling pathway to be always active to see what happens to the cell."
Thanks to the work done by countless researchers over the years, Raouf says it is now understood that "the signals that regulate the normal function of adult stem cells are the same signals that are perturbed when cancer occurs. They are completely involved in breast cancer initiation and progression of the disease."
As a result, a lot of cancer stem cell research is based on the belief that the disease doesn't initiate in tumour cells, but rather at a much earlier stage in the life of stem cells. If researchers can discover the cancer-initiating mechanism in stem cells, then maybe they can target it with new treatments. "In doing so, it is believed new treatments would be much more effective in the longer term by targeting the root of the cancer," says Hicks.
Raouf's work offers an example of this approach. The stem cells he showcased under the microscope have been engineered to be free of certain genes (known as NOTCH genes) that have been associated with cancer. "We know that there is a link. We know that in a mouse, if we hyper-activate this particular signalling cascade (grouping of genes), it leads to breast tumours. We just haven't been able to figure out what it does that is so bad."
Drugs have been used to inhibit this particular signalling cascade when it does become hyperactive, explains Raouf. The only problem is the drugs may often do more harm than good because they target the entire signalling cascade, which is fundamental to the survival of every cell.
"What we're trying to understand is what genes are involved in the signalling pathway that we can target instead of shutting down the whole signalling pathway. By being so specific, we're hoping to lessen the side-effects and make it more tolerable," says Raouf.
"How do we do that? First, we have to figure out specifically what this pathway does. Then we go after the specific genes activated by this pathway, and then we'll find their association with cancer. Then we will move forward to determine whether they can be targeted by drugs."
Other researchers in the lab are also using genes to manipulate embryonic or adult stem cells to replace or repair damaged cells. If researchers can understand the role played by these genes, and then program the stem cell to target specific conditions and diseases, they can start administering stem cell therapies to patients.
So, for example, stem cells could be used to grow new skin or new tissue to transplant into a patient. Right now, when heart muscle is damaged, it cannot regenerate and repair itself. But if a stem cell can be programmed to grow into brand new replacement tissue or a new valve, then patients could get a stem cell therapy transplant or a healthy new organ or new tissues for surgical transplant. Or specialized stem cells could be transplanted into patients to attack and wipe out common diseases.
It all comes down to understanding how embryonic stem cells, those building blocks of every cell in our bodies, grow into normal cells or grow into disease-initiating cells. It's also about understanding how to reprogram those cells to regenerate, replace or repair cells. It is through this kind of research that scientists hope to understand how to harness the power of stem cells to create replacement cells for the human body.
In some cases, that might mean coming up with breakthroughs in treating cancer or heart disease. In other cases, it might mean figuring out how to repair a damaged rotator cuff or growing new teeth. But in every case, the promise of stem cell research is that it has the power to significantly improve someone's overall quality of life, says Hicks.
Robin Summerfield is a Winnipeg writer.
* * *
Meet the Regenerative Medicine team
To put the significance of the Regenerative Medicine Program into perspective, consider this: Prior to 2008, there were no stem cell biologists working on research in Manitoba.
Today, the program at the University of Manitoba's Faculty of Medicine is the largest in Western Canada. More importantly, the Manitoba scientists are also working under one roof in a modern, integrated laboratory that lends itself to the sharing of information and ideas among researchers. The program provides Manitoba scientists with a sound foundation on which to continue their work and build relationships with other stem cell researchers around the world.
Here is a brief overview of each of the program's lead researchers and their work:
Dr. Geoff Hicks
As Director of the Regenerative Medicine Program, Dr. Geoff Hicks wears many hats, from fundraiser to lab designer. But first and foremost, he is a scientist.
For much of the last 25 years, Hicks has been focusing his attention on Ewing's Sarcoma and leukemia. He uses embryonic stem cells from mice to understand the influence of genetic changes that occur at a cellular level when disease arises.
Currently, his work is focused on TLS, a new and important class of cancer gene which is a known genetic determinant of leukemia and sarcoma. TLS is also very closely related to the EWS cancer gene, which is a known genetic determinant of Ewing's Sarcoma. So far, he has been able to demonstrate that the normal function of TLS is essential for preventing the accumulation of genetic mutations in cells (the major cause of cancer progression). His team's recent studies have shown TLS can regulate microRNAs, which in turn, can regulate multiple signalling pathways at the same time.
As it turns out, Hicks' research in this area has implications for one of the more significant stem cell discoveries in recent years - the discovery in 2007 of induced pluripotent stem cells (iPS). These cells, which are derived from adult stem cells, have some of the same characteristics as embryonic stem cells.
This discovery is important because as potentially useful as embryonic stem cells are, they do have some drawbacks. For example, people who receive stem cells from another individual, such as a patient who receives a bone marrow transplant from a relative, are also likely to require medication to ensure the body doesn't attack the transplanted stem cells.
In that sense, the transplant of stem cells is a lot like the transplant of kidneys or lungs. If the recipient is not a close genetic match to the donor, the body will reject the transplant. And even a recipient who is a close match must still take drugs to prevent their body from rejecting the transplanted organ. So even as scientists get closer to learning how to use embryonic stem cells to repair a heart or treat cancer, the problem associated with stem cell rejection remains.
The discovery of iPS cells changes the equation because they can be created from an individual's own stem cells. In other words, the patient can be the donor. That means the stem cells are not likely to be rejected and medication will not be required.
Still one problem remains. Two of the four genes required to transform adult stem cells into iPS cells are actually associated with cancer. In other words, the process of using stem cells to cure one disease could lead to the development of another.
This is where the work of Hicks and his collaborator, Dr. Lin He at Berkely UC, comes into play. The two scientists recently published a paper in Nature Cell Biology that argued adult stem cells could be transformed into iPS cells by switching out the cancer genes with those that are known to be less cancer-prone or may even block cancer.
Dr. Donna Wall
Dr. Donna Wall knows a lot about the potential of stem cells.
As the Director of the Blood and Marrow Transplant Program, Wall is responsible for overseeing the management of cellular therapy products used in blood and marrow transplantation.
Essentially, a bone marrow transplant is the transfer of blood stem cells from a healthy donor to a patient whose bone marrow cells are damaged, most often by cancer.
The first bone marrow transplants took place in the early 1960s after two Canadian scientists demonstrated the regenerative powers of haematopoietic (blood) stem cells, the kind found in bone marrow.
A bone marrow transplant changes the body's immune system as well as other components made by blood. "In order to do this, we have to have a donor who is immune-matched," explains Wall. "And for our patients in Manitoba, we will search world-wide to find the very best donor for them," says Wall, who graduated from the University of Manitoba's Faculty of Medicine in 1981 and spent 27 years working in the United States before returning home in 2008.
As members of the Regenerative Medicine Program pursue their research, Wall and her team will play an integral role in the work of the lab. "By definition, we are already regenerating the blood-making system of people," says Wall.
Looking ahead, Wall says the lab is moving forward with plans to ensure it has the capacity to handle the manufacturing of cells for therapies developed by the Regenerative Medicine Program.
Once a particular therapy is ready to be tested in patients in clinical trial, Wall's lab would be responsible for ensuring the stem cells being used are of the highest quality. "Our job would be to scale it up the laboratory findings for clinical trials in humans."
Dr. Soheila Karimi
Dr. Soheila Karimi hopes her research will one day help paralyzed people regain some mobility. It's a hope that has been bolstered by a decade of work in her laboratory.
Paralysis occurs when the spinal cord, which, along with the brain, forms the central nervous system, suffers a severe injury. One of the main consequences of spinal cord injury is the damage to the myelin sheath, which surrounds the nerve fibres that transmit signals from the brain to the spinal cord. The myelin sheath is normally made by myelin forming cells, namely oligodendrocytes. After a spinal cord injury, oligodendrocytes die and the myelin sheath is damaged, leading to body paralysis and a loss of sensation in patients.
In 2006, Karimi was able to restore some mobility to a rat with a spinal cord injury using stem cell therapy to replenish lost oligodendrocytes and repair the myelin sheath. As she explains, an injured spinal cord is a "hostile" environment for transplanted stem cells. To optimize their ability to regenerate the damaged myelin, she created a more permissive environment for them. "We targeted some of the inhibitory factors inside the spinal cord and provided some growth factors at the time of transplantation," she says.
It was a huge breakthrough, garnering worldwide media attention and earning Karimi a Synthes Award from the American Association of Neurological Surgeons. "That was really rewarding because you work really hard for a long time, and feel that you have become one step closer," she says. But that success was just the start. "There is still a big gap from bench to bed," Karimi says. "The big question is how can we take advantage of the promise of stem cells in people?"
To that end, Karimi is trying to identify ways to stimulate the stem cells that already exist within the injured spinal cord. The problem is the residing stem cells are inhibited in their injury environment and not differentiating into the right kinds of cells, and the regeneration is minimal. "We are currently manipulating the environment of spinal cord injury by neutralizing some inhibitory factors and activating essential differentiation factors to harness the repair potential of stem cells," she says. In doing so, Karimi and her team hope to develop new therapies to stimulate the stem cells enough to begin repairing the damaged spinal cord from inside.
Dr. Afshin Raouf
An auto mechanic needs to know how a car is supposed to work to understand what is wrong when it is not running properly. The same goes for understanding disease, says breast cancer researcher Dr. Afshin Raouf.
By understanding how healthy breast tissue stem cells behave, Raouf hopes to better understand why and how tumour cells arise and grow. Understanding normal will help researchers better understand what's not normal, he says.
Raouf has a bit of an edge in that department. While completing his post-doctoral work in Vancouver four years ago, Raouf became the first person in the world to figure out how to isolate adult breast stem cells from tissue left over from breast reduction surgery.
Previously, researchers did have the ability to derive adult stem cells from discarded breast tissue, but the processes used were time-consuming and inefficient. Raouf's technique - which took him seven years to perfect - is much quicker and more efficient, which makes it much easier for him to conduct his research.
Currently, Raouf and his team are manipulating adult breast stem cells by withholding and adding certain genes. They want to understand the signals that fire to create normal cells and the signals that don't fire, letting cells continue to grow into abnormal cells.
In the meantime, he draws strength from people getting chemotherapy or radiation to treat their cancers a few floors down in CancerCare at the Health Sciences Centre.
"This building is where the real pain of cancer is," says Raouf. 'They are my source of inspiration."
Dr. Mojgan Rastegar
The key to curing "abnormal" is to understand "normal."
That's the starting premise for Dr. Mojgan Rastegar's research into the causes of Rett Syndrome (RTT), an autism-spectrum disorder that affects about one in 10,000 children, primarily females.
Children with Rett Syndrome may start off developing normally and at six to 18 months of age exhibit intellectual disabilities, seizures, impaired communications, unintentional hand movements and autism.
Rastegar is careful to point out that RTT is not a neuro-degenerative disease. "The neurons are not damaged," she says. "They are not fully matured."
This happens in some children and the underlying cause is mutations in the X-linked MECP2 gene, a gene that is key to normal nerve function and has been linked to other neurological disorders beyond autism and RTT. In fact, RTT is the only autismspectrum disorder with a clearly understood genetic cause. "In 95 per cent of cases, Rett Syndrome is caused by a mutation in the MECP2 gene," she says.
As a result, Rastegar, along with scientists around the world, have been looking for ways to reintroduce or replenish the gene in neural cells where it is deficient. And she has had some success in neural stem cells and neurons from a RTT mouse model. While working at Toronto's Sick Kids Hospital, Rastegar relieved morphological deficiencies in neurons from RTT mice, by gene therapy delivery of MECP2 gene.
As a member of the Regenerative Medicine team at the University of Manitoba, Rastegar will be building on her work in two ways. First, she will continue researching neural stem cells to gain a deeper understanding of how the MECP2 gene is regulated and its functions. Second, Rastegar and her team will continue to generate and test viruses that can be used to re-introduce the MECP2 gene into the cells that are deficient.
Rastegar says RTT is a good candidate for gene therapy because it is caused by a singlegene mutation. As she explains, diseases with multiple causes are more difficult to deal with.
"We are hoping that one day we could have a gene therapy approach. However, at the same time, we aim to develop efficient, alternative, innovative therapeutic strategies," she says.
* * *
Stem cell timeline
Here is an abbreviated timeline of developments in stem cell research.
1860 to 1920
Stem cells are inferred from analysis of embryo development and microscopy of bone marrow (Germany).
1948 to 1958
Stem cell mechanisms are deduced for sperm development and intestinal epithelium replacement (Canada).
The existence and properties of transplantable stem cells in mouse bone marrow are established and the first colony methodology for counting them is introduced. This discovery set the stage for all current research on adult and embryonic stem cells (Canada).
First cell separation technology is applied to dissect marrow stem cell hierarchy (Canada).
Transplantable stem cells are discovered in human cord blood (USA).
Embryonic stem cells are first derived from the inner cell mass of mouse blastocysts (UK, USA).
Neural stem cells are identified in the adult human brain (Canada).
Pluripotency of embryonic stem cells is proven through the generation of entirely embryonic stem cellderived mice (Canada).
Cancer stem cells are first separated from the majority of cells in a cancer (Canada). Patients with damaged corneas are treated with corneal stem cells (Taiwan).
First cloning of a mammal: Dolly the sheep is born (Scotland).
First human embryonic stem cell line derived (USA).
Normal mammary stem cells are demonstrated in adult mice (Australia, Canada, USA). First induced pluripotent stem cells (iPS) are generated by reprogramming adult mouse skin cells. Altered iPS cells have characteristics similar to embryonic stem cells (Japan).
Sam Weiss is awarded the Gairdner Prize for the discovery of neural stem cells (Canada).
iPS cells created with minimal residual genomic alteration (Canada).
Adult cells are reprogrammed directly to neurons, cardiac muscle and blood cells (Canada, USA). First clinical trial of human embryonic-derived stem cells for treatment of spinal cord injury begins (USA).
Multipotent human blood stem cells capable of forming all cells in the blood system are isolated (Canada).
Source: The Stem Cell Network
Have you found an error, or know of something we’ve missed in one of our stories? Please use the form below and let us know.
More Research & Innovation
More Research & Innovation
(1 of 8 articles for this year)11/13/2013 11:00 AM 0