CIRM Board Awards $15.8 Million to Four Translational Research Projects

Last week, the CIRM Board approved $32.92 million in awards directed towards four new clinical trials in vision related diseases and Parkinson’s Disease.

In addition to these awards, the Board also approved investing $15.80 million in four awards in the Translational Research program. The goal of this program is to help promising projects complete the testing needed to begin talking to the US Food and Drug Administration (FDA) about holding a clinical trial.

Before we go into more specific details of each one of these awards, here is a table summarizing these four new projects:

ApplicationTitleInstitutionAward Amount
TRAN1 11536Ex Vivo Gene Editing of Human Hematopoietic Stem Cells for the Treatment of X-Linked Hyper IgM Syndrome  UCLA $4,896,628
TRAN1 11555BCMA/CS1 Bispecific CAR-T Cell Therapy to Prevent Antigen Escape in Multiple Myeloma  UCLA $3,176,805
TRAN1 11544 Neural Stem cell-mediated oncolytic immunotherapy for ovarian cancer  City of Hope $2,873,262
TRAN1 11611Development of a human stem cell-derived inhibitory neuron therapeutic for the treatment of chronic focal epilepsyNeurona Therapeutics$4,848,750
Dr. Caroline Kuo, UCLA

$4.89 million was awarded to Dr. Caroline Kuo at UCLA to pursue a gene therapy approach for X-Linked Hyper IgM Syndrome (X-HIM).

X-HIM is a hereditary immune disorder observed predominantly in males in which there are abnormal levels of different types of antibodies in the body.  Antibodies are also known as Immunoglobulin (Ig) and they combat infections by attaching to germs and other foreign substances, marking them for destruction.  In infants with X-HIM, there are normal or high levels of antibody IgM but low levels of antibodies IgG, IgA, and IgE.  The low level of these antibodies make it difficult to fight off infection, resulting in frequent pneumonia, sinus infections, ear infections, and parasitic infections.  Additionally, these infants have an increased risk of cancerous growths. 

The gene therapy approach Dr. Kuo is continuing to develop involves using CRISPR/Cas9 technology to modify human blood stem cells with a functional version of the gene necessary for normal levels of antibody production.  The ultimate goal would be to take a patient’s own blood stem cells, modify them with the corrected gene, and reintroduce them back into the patient.

CIRM has previously funded Dr. Kuo’s earlier work related to developing this gene therapy approach for XHIM.

Dr. Yvonne Chen, UCLA

$3.17 million was awarded to Dr. Yvonne Chen at UCLA to develop a CAR-T cell therapy for multiple myeloma (MM).

MM is a type of blood cancer that forms in the plasma cell, a type of white blood cell that is found in the bone marrow.  An estimated 32,110 people in the United States will be diagnosed with MM in 2019 alone.  Several treatment options are available to patients with MM, but there is no curative therapy.

The therapy that Dr. Chen is developing will consist of a genetically-modified version of the patient’s own T cells, which are an immune system cell that can destroy foreign or abnormal cells.  The T cells will be modified with a protein called a chimeric antigen receptor (CAR) that will recognize BCMA and CS1, two different markers found on the surface of MM cells.  These modified T cells (CAR-T cells) are then infused into the patient, where they are expected to detect and destroy BCMA and CS1 expressing MM cells.

Dr. Chen is using CAR-T cells that can detect two different markers in a separate clinical trial that you can read about in a previous blog post.

Dr. Karen Aboody, City of Hope

$2.87 million was awarded to Dr. Karen Aboody at City of Hope to develop an immunotherapy delivered via neural stem cells (NSCs) for treatment of ovarian cancer.

Ovarian cancer affects approximately 22,000 women per year in the United States alone.  Most ovarian cancer patients eventually develop resistance to chemotherapy, leading to cancer progression and death, highlighting the need for treatment of recurring ovarian cancer.

The therapy that Dr. Aboody is developing will use an established line of NSCs to deliver a virus that specifically targets these tumor cells.  Once the virus has entered the tumor cell, it will continuously replicate until the cell is destroyed.  The additional copies of the virus will then go on to target neighboring tumor cells.  This process could potentially stimulate the body’s own immune response to fight off the cancer cells as well.

Dr. Cory Nicholas, Neurona Therapeutics

$4.85 million was awarded to Dr. Cory Nicholas at Neurona Therapeutics to develop a treatment for epilepsy.

Epilepsy affects more than 3 million people in the United States with about 150,000 newly diagnosed cases in the US every year. It results in persistent, difficult to manage, or uncontrollable seizures that can be disabling and significantly impair quality of life. Unfortunately, anti-epileptic drugs fail to manage the disease in a large portion of people with epilepsy. Approximately one-third of epilepsy patients are considered to be drug-resistant, meaning that they do not adequately respond to at least two anti-epileptic drugs.

The therapy that Dr. Nicholas is developing will derive interneurons from human embryonic stem cells (hESCs). These newly derived interneurons would then be delivered to the brain via injection whereby the new cells are able to help regulate aberrant brain activity and potentially eliminate or significantly reduce the occurrence of seizures.

CIRM has previously funded the early stage development of this approach via a comprehensive grant and discovery grant.

From bench to bedside: a Q&A with stem cell expert Jan Nolta

At CIRM we are privileged to work with many remarkable people who combine brilliance, compassion and commitment to their search for new therapies to help people in need. One of those who certainly fits that description is UC Davis’ Jan Nolta.

This week the UC Davis Newsroom posted a great interview with Jan. Rather than try and summarize what she says I thought it would be better to let her talk for herself.

Jan Nolta
Jan Nolta

Talking research, unscrupulous clinics, and sustaining the momentum

(SACRAMENTO) —

In 2007, Jan Nolta returned to Northern California from St. Louis to lead what was at the time UC Davis’ brand-new stem cell program. As director of the UC Davis Stem Cell Program and the Institute for Regenerative Cures, she has overseen the opening of the institute, more than $140 million in research grants, and dozens upon dozens of research studies. She recently sat down to answer some questions about regenerative medicine and all the work taking place at UC Davis Health.

Q: Turning stem cells into cures has been your mission and mantra since you founded the program. Can you give us some examples of the most promising research?

I am so excited about our research. We have about 20 different disease-focused teams. That includes physicians, nurses, health care staff, researchers and faculty members, all working to go from the laboratory bench to patient’s bedside with therapies.

Perhaps the most promising and exciting research right now comes from combining blood-forming

stem cells with gene therapy. We’re working in about eight areas right now, and the first cure, something that we definitely can call a stem cell “cure,” is coming from this combined approach.

Soon, doctors will be able to prescribe this type of stem cell therapy. Patients will use their own bone marrow or umbilical cord stem cells. Teams such as ours, working in good manufacturing practice facilities, will make vectors, essentially “biological delivery vehicles,” carrying a good copy of the broken gene. They will be reinserted into a patient’s cells and then infused back into the patient, much like a bone marrow transplant.

“Perhaps the most promising and exciting research right now comes from combining blood-forming stem cells with gene therapy.”

Along with treating the famous bubble baby disease, where I had started my career, this approach looks very promising for sickle cell anemia. We’re hoping to use it to treat several different inherited metabolic diseases. These are conditions characterized by an abnormal build-up of toxic materials in the body’s cells. They interfere with organ and brain function. It’s caused by just a single enzyme. Using the combined stem cell gene therapy, we can effectively put a good copy of the gene for that enzyme back into a patient’s bone marrow stem cells. Then we do a bone marrow transplantation and bring back a person’s normal functioning cells.

The beauty of this therapy is that it can work for the lifetime of a patient. All of the blood cells circulating in a person’s system would be repaired. It’s the number one stem cell cure happening right now. Plus, it’s a therapy that won’t be rejected. These are a patient’s own stem cells. It is just one type of stem cell, and the first that’s being commercialized to change cells throughout the body.

Q: Let’s step back for a moment. In 2004, voters approved Proposition 71. It has funded a majority of the stem cell research here at UC Davis and throughout California. What’s been the impact of that ballot measure and how is it benefiting patients?

We have learned so much about different types of stem cells, and which stem cell will be most appropriate to treat each type of disease. That’s huge. We had to first do that before being able to start actual stem cell therapies. CIRM [California Institute for Regenerative Medicine] has funded Alpha Stem Cell Clinics. We have one of them here at UC Davis and there are only five in the entire state. These are clinics where the patients can go for high-quality clinical stem cell trials approved by the FDA [U.S. Food and Drug Administration]. They don’t need to go to “unapproved clinics” and spend a lot of money. And they actually shouldn’t.

“By the end of this year, we’ll have 50 clinical trials.”

By the end of this year, we’ll have 50 clinical trials [here at UC Davis Health]. There are that many in the works.

Our Alpha Clinic is right next to the hospital. It’s where we’ll be delivering a lot of the immunotherapies, gene therapies and other treatments. In fact, I might even get to personally deliver stem cells to the operating room for a patient. It will be for a clinical trial involving people who have broken their hip. It’s exciting because it feels full circle, from working in the laboratory to bringing stem cells right to the patient’s bedside.

We have ongoing clinical trials for critical limb ischemia, leukemia and, as I mentioned, sickle cell disease. Our disease teams are conducting stem cell clinical trials targeting sarcoma, cellular carcinoma, and treatments for dysphasia [a swallowing disorder], retinopathy [eye condition], Duchenne muscular dystrophy and HIV. It’s all in the works here at UC Davis Health.

There’s also great potential for therapies to help with renal disease and kidney transplants. The latter is really exciting because it’s like a mini bone marrow transplant. A kidney recipient would also get some blood-forming stem cells from the kidney donor so that they can better accept the organ and not reject it. It’s a type of stem cell therapy that could help address the burden of being on a lifelong regime of immunosuppressant drugs after transplantation.

Q: You and your colleagues get calls from family members and patients all the time. They frequently ask about stem cell “miracle” cures. What should people know about unproven treatments and unregulated stem cell clinics?

That’s a great question.The number one rule is that if you’re asked to pay money for a stem cell treatment, don’t do it. It’s a big red flag.

When it comes to advertised therapies: “The number one rule is that if you’re asked to pay money for a stem cell treatment, don’t do it. It’s a big red flag.”

Unfortunately, there are unscrupulous people out there in “unapproved clinics” who prey on desperate people. What they are delivering are probably not even stem cells. They might inject you with your own fat cells, which contain very few stem cells. Or they might use treatments that are not matched to the patient and will be immediately rejected. That’s dangerous. The FDA is shutting these unregulated clinics down one at a time. But it’s like “whack-a-mole”: shut one down and another one pops right up.

On the other hand, the Alpha Clinic is part of our mission is to help the public get to the right therapy, treatment or clinical trial. The big difference between those who make patients pay huge sums of money for unregulated and unproven treatments and UC Davis is that we’re actually using stem cells. We produce them in rigorously regulated cleanroom facilities. They are certified to contain at least 99% stem cells.

Patients and family members can always call us here. We can refer them to a genuine and approved clinical trial. If you don’t get stem cells at the beginning [of the clinical trial] because you’re part of the placebo group, you can get them later. So it’s not risky. The placebo is just saline. I know people are very, very desperate. But there are no miracle cures…yet. Clinical trials, approved by the FDA, are the only way we’re going to develop effective treatments and cures.

Q: Scientific breakthroughs take a lot of patience and time. How do you and your colleagues measure progress and stay motivated?   

Motivation?  “It’s all for the patients.”

It’s all for the patients. There are not good therapies yet for many disorders. But we’re developing them. Every day brings a triumph. Measuring progress means treating a patient in a clinical trial, or developing something in the laboratory, or getting FDA approval. The big one will be getting biological license approval from the FDA, which means a doctor can prescribe a stem cell or gene therapy treatment. Then it can be covered by a patient’s health insurance.

I’m a cancer survivor myself, and I’m also a heart patient. Our amazing team here at UC Davis has kept me alive and in great health. So I understand it from both sides. I understand the desperation of “Where do I go?” and “What do I do right now?” questions. I also understand the science side of things. Progress can feel very, very slow. But everything we do here at the Institute for Regenerative Cures is done with patients in mind, and safety.

We know that each day is so important when you’re watching a loved one suffer. We attend patient events and are part of things like Facebook groups, where people really pour their hearts out. We say to ourselves, “Okay, we must work harder and faster.” That’s our motivation: It’s all the patients and families that we’re going to help who keep us working hard.

Stories of the week – preterm birth and mice with a human immune system

While we are here at ISSCR 2019 hearing various scientists talk about their work, we realize that there are various breakthroughs in stem cell research in a wide variety of different fields going on every day. It is wonderful to see how scientists are hard at work in developing the latest science and pushing innovation. Here are two remarkable stories you may have missed this week.

Scientists developing way to help premature babies breathe easier

Researchers at Cincinnati Children’s Hospital Medical Center are looking at ways to stimulate lung development in premature infants who suffer from a rare condition called Bronchopulmonary Dysplasia (BPD), which can cause lifelong breathing problems and even death. Using a mouse model of BPD, extensive analysis, and testing, the scientists were able to create a proposal to develop a stem cell therapy based on what are called c-KIT endothelial progenitor cells.

Premature babies, unable to breathe on their own, rely on machines to help them breathe. Unfortunately, these machines can interfere with lung development as well. The cells proposed in the stem cell therapy are common in the lungs of infants still in the womb and help in the formation of capillaries and air sacs in the lungs called alveoli.

In a press release, Dr. Vlad Kalinichenko, lead investigator for this work, was quoted as saying,

“The cells are highly sensitive to injury by high oxygen concentrations, so lung development in premature babies on mechanical oxygen assistance is impeded. Our findings suggest using c-KIT-positive endothelial cells from donors, or generating them with pluripotent stem cells, might be a way to treat BPD or other pediatric lung disorders associated with loss of alveoli and pulmonary microvasculature.”

The full results were published in American Journal of Respiratory and Critical Care Medicine.

Mice with a human immune system help research into cancer and infections

Speaking of a mouse model, researchers from Aarhus University and Aarhus University Hospital have succeeded in using mice with a transplanted human immune system to study functions in the immune system which are otherwise particularly difficult to study. This work could open the possibilities towards looking further into disease areas such as cancer, HIV, and autoimmune diseases.

Before potential treatments can be tested in humans, there needs to be extensive animal testing and data generated. However, when the disease relate’s to the human immune system, it can be particularly challenging to evaluate this in mice. The research team succeeded in transplanting human stem cells into mice whose own immune system is disabled, and then triggered a type of reaction in the immune system which normally reacts to meeting a range of viruses and bacteria.

In a press release, Dr. Anna Halling Folkmar, one of the researchers behind the study, says that,

“The humanised mice are an important tool in understanding how human immune cells behave during diseases and how they react to different medical treatments.”

The full results were published in Immunology.

Seeing is believing: A new tool to help us learn about stem cells.

Cave paintings from Libya: evidence humans communicated through visual images long before they created text

There’s a large body of research that shows that many people learn better through visuals. Studies show that much of the sensory cortex in our brain is devoted to vision so our brains use images rather than text to make sense of things.

That’s why we think it just makes sense to use visuals, as much as we can, when trying to help people understand advances in stem cell research. That’s precisely what our colleagues at U.C. San Diego are doing with a new show called “Stem Cell Science with Alysson Muotri”.

Alysson is a CIRM grantee who is doing some exciting work in developing a deeper understanding of autism. He’s also a really good communicator who can distill complex ideas down into easy to understand language.

The show features Alysson, plus other scientists at UCSD who are working hard to move the most promising research out of the lab and into clinical trials in people. Appropriately the first show in the series follows that path, exploring how discoveries made using tiny Zebrafish could hopefully lead to stem cell therapies targeting blood diseases like leukemia. This first show also highlights the important role that CIRM’s Alpha Stem Cell Clinic Network will play in bringing those therapies to patients.

You can find a sneak preview of the show on YouTube. The series proper will be broadcast on California local cable via the UCTV channel at 8:00 pm on Thursdays starting July 8, 2019. 

And if you really have a lot of time on your hands you can check out the more than 300 videos CIRM has produced on every aspect of stem cell research from cures for fatal diseases to questions to ask before taking part in a clinical trial.

Newly developed biosensor can target leukemic stem cells

Dr. Michael Milyavsky (left) and his research student Muhammad Yassin (right). Image courtesy of Tel Aviv University.

Every three minutes, one person in the United States is diagnosed with a blood cancer, which amounts to over 175,000 people every year. Every nine minutes, one person in the United States dies from a blood cancer, which is over 58,000 people every year. These eye opening statistics from the Leukemia & Lymphoma Society demonstrate why almost one in ten cancer deaths in 2018 were blood cancer related.

For those unfamiliar with the term, a blood cancer is any type of cancer that begins in blood forming tissue, such as those found in the bone marrow. One example of a blood cancer is leukemia, which results in the production of abnormal blood cells. Chemotherapy and radiation are used to wipe out these cells, but the blood cancer can sometimes return, something known as a relapse.

What enables the return of a blood cancer such as leukemia ? The answer lies in the properties of cancer stem cells, which have the ability to multiply and proliferate and can resist the effects of certain types of chemotherapy and radiation. Researchers at Tel Aviv University are looking to decrease the rate of relapse in blood cancer by targeting a specific type of cancer stem cell known as a leukemic stem cell, which are often found to be the most malignant.

Dr. Michael Milyavsky and his team at Tel Aviv University have developed a biosensor that is able to isolate, label, and target specific genes found in luekemic stem cells. Their findings were published on January 31, 2019 in Leukemia.

In a press release Dr. Milyavsky said:

“The major reason for the dismal survival rate in blood cancers is the inherent resistance of leukemic stem cells to therapy, but only a minor fraction of leukemic cells have high regenerative potential, and it is this regeneration that results in disease relapse. A lack of tools to specifically isolate leukemic stem cells has precluded the comprehensive study and specific targeting of these stem cells until now.”

In addition to isolating and labeling leukemic stem cells, Dr. Milyavsky and his team were able to demonstrate that the leukemic stem cells labeled by their biosensor were sensitive to an inexpensive cancer drug, highlighting the potential this technology has in creating more patient-specific treatment options.

In the article, Dr. Milyavsky said:

” Using this sensor, we can perform personalized medicine oriented to drug screens by barcoding a patient’s own leukemia cells to find the best combination of drugs that will be able to target both leukemia in bulk as well as leukemia stem cells inside it.”

The researchers are now investigating genes that are active in leukemic stem cells in the hope finding other druggable targets.

CIRM has funded two clinical trials that also use a more targeted approach for cancer treatment. One of these trials uses an antibody to treat chronic lymphocytic leukemia (CLL) and the other trial uses a different antibody to treat acute myeloid leukemia (AML).

Antibody effective in cure for rare blood disorders

3D illustration of an antibody binding to a designated target.
Illustration created by Audra Geras.

A variety of diseases can be traced to a simple root cause: problems in the bone marrow. The bone marrow contains specialized stem cells known as hematopoietic stem cells (HSCs) that give rise to different types of blood cells. As mentioned in a previous blog about Sickle Cell Disease (SCD), one problem that can occur is the production of “sickle like” red blood cells. In blood cancers like leukemia, there is an uncontrollable production of abnormal white blood cells. Another condition, known as myelodysplastic syndromes (MDS), are a group of cancers in which immature blood cells in the bone marrow do not mature and therefore do not become healthy blood cells.

For diseases that originate in the bone marrow, one treatment involves introducing healthy HSCs from a donor or gene therapy. However, before this type of treatment can take place, all of the problematic HSCs must be eliminated from the patient’s body. This process, known as pre-treatment, involves a combination of chemotherapy and radiation, which can be extremely toxic and life threatening. There are some patients whose condition has progressed to the point where their bodies are not strong enough to withstand pre-treatment. Additionally, there are long-term side effects that chemotherapy and radiation can have on infant children that are discussed in a previous blog about pediatric brain cancer.

Could there be a targeted, non-toxic approach to eliminating unwanted HSCs that can be used in combination with stem cell therapies? Researchers at Stanford say yes and have very promising results to back up their claim.

Dr. Judith Shizuru and her team at Stanford University have developed an antibody that can eliminate problematic blood forming stem cells safely and efficiently. The antibody is able to identify a protein on HSCs and bind to it. Once it is bound, the protein is unable to function, effectively removing the problematic blood forming stem cells.

Dr. Shizuru is the senior author of a study published online on February 11th, 2019 in Blood that was conducted in mice and focused on MDS. The results were very promising, demonstrating that the antibody successfully depleted human MDS cells and aided transplantation of normal human HSCs in the MDS mouse model.

This proof of concept holds promise for MDS as well as other disease conditions. In a public release from Stanford Medicine, Dr. Shizuru is quoted as saying, “A treatment that specifically targets only blood-forming stem cells would allow us to potentially cure people with diseases as varied as sickle cell disease, thalassemia, autoimmune disorders and other blood disorders…We are very hopeful that this body of research is going to have a positive impact on patients by allowing better depletion of diseased cells and engraftment of healthy cells.”

The research mentioned was partially funded by us at CIRM. Additionally, we recently awarded a $3.7 million dollar grant to use the same antibody in a human clinical trial for the so-called “bubble baby disease”, which is also known as severe combined immunodeficiency (SCID). You can read more about that award on a previous blog post linked here.

Mechanical forces are the key to speedy recovery after blood cancer treatment

MIT-Stem-Cell-Mechanics_0

Mesenchymal stem cells grown on a surface with specialized mechanical properties. Image courtesy of Krystyn Van Vliet at MIT.

Blood cancers, such as leukemia and lymphoma, are projected to be responsible for 10% of all new cancer diagnoses this year. These types of cancers are often treated by killing the patient’s bone marrow (the site of blood cell manufacturing), with a treatment called irradiation. While effective for ridding the body of cancerous cells, this treatment also kills healthy blood cells. Therefore, for a time after the treatment, patients are particularly vulnerable to infections, because the cellular components of the immune system are down for the count.

Now scientists at MIT have devised a method to make blood cells regenerate faster and  minimize the window for opportunistic infections.

Using multipotent stem cells (stem cells that are able to become multiple cell types) grown on a new and specialized surface that mimics bone marrow, the investigators changed the stem cells into different types of blood cells. When transplanted into mice that had undergone irradiation, they found that the mice recovered much more quickly compared to mice given stem cells grown on a more traditional plastic surface that does not resemble bone marrow as well.

This finding, published in the journal Stem Cell Research and Therapy, is particularly revolutionary, because it is the first time researchers have observed that mechanical properties can affect how the cells differentiate and behave.

The lead author of the study attributes the decreased recovery time to the type of stem cell that was given to mice compared to what humans are normally given after irradiation. Humans are given a stem cell that is only able to become different types of blood cells. The mice in this study, however, were give a stem cell that can become many different types of cells such as muscle, bone and cartilage, suggesting that these cells somehow changed the bone marrow environment to promote a more efficient recovery. They attributed a large part of this phenomenon to a secreted protein call ostepontin, which has previously been describe in activating the cells of the immune system.

In a press release, Dr. Viola Vogel, a scientist not related to study, puts the significance of these findings in a larger context:

“Illustrating how mechanopriming of mesenchymal stem cells can be exploited to improve on hematopoietic recovery is of huge medical significance. It also sheds light onto how to utilize their approach to perhaps take advantage of other cell subpopulations for therapeutic applications in the future.”

Dr. Krystyn Van Vliet, explains the potential to expand these findings beyond the scope of just blood cancer treatment:

“You could imagine that by changing their culture environment, including their mechanical environment, MSCs could be used for administration to target several other diseases such as Parkinson’s disease, rheumatoid arthritis, and others.”

 

Support cells have different roles in blood stem cell maintenance before and after stress

How-Stem-Cells-Act-When-Stressed-Versus-When-At-Rest

Expression of pleiotrophin (green) in bone marrow blood vessels (red) and stromal cells (white) in normal mice (left), and in mice 24 hours after irradiation (right). UCLA Broad Stem Cell Research Center/Cell Stem Cell

A new study published in the journal Cell Stem Cell, reveals how different types of cells in the bone marrow are responsible for supporting blood stem cell maintenance before and after injury.

It was already well known in the field that two different cell types, namely endothelial cells (which line blood vessels) and stromal cells (which make up connective tissue, or tissue that provides structural support for any organ), are responsible for maintaining the population of blood stem cells in the bone marrow. However, how these cells and the molecules they secrete impact blood stem cell development and maintenance is not well understood.

Hematopoietic stem cells are responsible for generating the multiple different types of cells found in blood, from our oxygen carrying red blood cells to the many different types of white blood cells that make up our immune system.

Dr. John Chute’s group at UCLA had previously discovered that a molecule called pleiotrophin, or PTN, is important for promoting self-renewal of the blood stem cell population. They did not, however, understand which cells secrete this molecule and when.

To answer this question, the scientists developed mouse models that did not produce PTN in different types of bone marrow cells, such as endothelial cells and stromal cells. Surprisingly, they saw that the inability of stromal cells to produce PTN decreased the blood stem cell population, but deletion of PTN in endothelial cells did not affect the blood stem cell niche.

Even more interestingly, the researchers found that in animals that were subjected to an environmental stressor, in this case, radiation, the result was reversed: endothelial cell PTN was necessary for blood stem cell renewal, whereas stromal cell PTN was not. While an important part of the knowledge base for blood stem cell biology, the reason for this switch in PTN secretion at times of homeostasis and disease is still unknown.

As Dr. Chute states in a press release, this result could have important implications for cancer treatments such as radiation:

“It may be possible to administer modified, recombinant versions of pleiotrophin to patients to accelerate blood cell regeneration. This strategy also may apply to patients undergoing bone marrow transplants.”

Another important consideration to take away from this work is that animal models developed in the laboratory should take into account the possibility that blood stem cell maintenance and regeneration is distinctly controlled under healthy and disease state. In other words, cellular function in one state is not always indicative of its role in another state.

This work was partially funded by a CIRM Leadership Award.

 

 

Blood stem cell expansion expands treatment options for cancer patients

Screen Shot 2018-08-07 at 10.19.30 AM

Image courtesy of the Stower’s Institute

Bone marrow transplants have been used for decades to treat various types of cancers such as leukemia and multiple myeloma, as well as other blood disorders such as anemia.

Our bone marrow is responsible for making hematopoietic stem cells (HSCs), which develop into mature blood cells, like white cells (which fight infection) and red cells (which carry oxygen throughout our body). In different types of blood disorders, blood cell production is either impaired or abnormal. In leukemia for example, the body produces abnormal white blood cells that survive better then outgrow the normal white cells, thus impairing the individual’s ability to fight infection. Bone marrow transplants, which involves replacing the diseased marrow with healthy marrow from a donor, can be incredibly effective for these types of disease. Survival from certain blood cancers increased from basically zero to around eighty-five percent after the advent of bone marrow transplant therapy.

While extremely effective when successful, bone marrow transplants do not work for everyone and finding a match can be difficult. For example, only 30% of patients are able to find a match in their families, because of the strict requirements that must be fulfilled be a bone marrow match. Stem cells from umbilical cord blood, on the other hand, are much more likely to match a patient, because of the generally less stringent requirements to be a match. The amount of cord blood (nearly two whole cords worth of blood) needed to satisfy an adult patient’s transplant requirements, however, are significant, and can be a limiting factor in the efficiency and effectiveness of this approach. New research from Lingheng Li’s lab at the Stower’s Institute for Medical Research at the University of Kansas has found a possible solution to this problem.

In a study published in Cell Research, Li’s group found a way to increase the number of adult stem cells isolated from cord blood, which could reduce the number of cords needed per treatment. By eliminating a protein called Ythdf2 in mice, they observed global expansion of HSCs. Normally, this protein is responsible for preventing expression of genes involved in promoting HSC expansion. Importantly, the researchers found that the HSC expansion stimulated by elimination of Ythdf2 did not lead to other abnormalities in the resulting HSCs and did not affect the ability of these HSCs to produce different types of blood stem cells down the road. Dr. Li believes that this type of approach can be applied to other types of stem cell treatments as well.

Dr. Joseph McGuirk, another professor at the University of Kansas who was not directly involved with this study, indicates the importance of this work:

“This work represents a path forward by demonstrating the ability to reliably expand adult stem cells from umbilical cord blood in the laboratory without terminally differentiating the cells into more mature and relatively short-lived blood cells. These findings represent a major advance in the field and have significant potential to improve the outcomes of thousands of children and adults who undergo umbilical cord blood transplantation every year.”

CIRM is funding work in this area too. We are supporting a late stage preclinical project with AngioCrine Biosciences which is using expanded cord blood stem cells. They hope to create an effective and, safe option for the treatment of debilitating blood diseases such as leukemia and lymphoma.

The Five Types of Stem Cells

When I give an “Intro to Stem Cells” presentation to, say, high school students or to a local Rotary Club, I begin by explaining that there are three main types of stem cells: (1) embryonic stem cells (ESCs) (2) adult stem cells and (3) induced pluripotent stem cells (iPSCs). Well, like most things in science, it’s actually not that simple.

To delve a little deeper into the details of characterizing stem cells, I recommend checking out a video animation produced by BioInformant, a stem cell market research company. The video is introduced in a blog, “Do you know the 5 types of stem cells?” by Cade Hildreth, BioInformant’s founder and president.

Stem-Cell-Types

Image credit: BioInformant

Hildreth’s list categorizes stem cells by the extent of each type’s shape-shifting abilities. So while we sometimes place ESCs and iPSCs in different buckets because the methods for obtaining them are very different, in this list, they both belong to the pluripotent stem cell type. Pluri (“many”) – potent (“potential”) refers to the ability of both stem cell types to specialize into all of the cell types in the body. They can’t, though, make the cells of the placenta and other extra-embryonic cells too. Those ultimate blank-slate stem cells are called toti (“total”) – potent (“potential”).

When it comes to describing adult stem cells in my talks, I often lump blood stem cells together with muscle stem cells because they are stem cells that are present within us throughout life. But based on their ability to mature into specialized cells, these two stem cell types fall into two different categories in Hildreth’s list:  blood stem cells which can specialize into closely related cell types – the various cell types found in the blood – are considered “oligopotent” while muscle stem cells are “unipotent” because the can only mature into one type of cell, a muscle cell.

For more details on the five types of stem cells based on their potential to specialize, head over to the BioInformant blog. And scroll to the very bottom for the video animation which can also viewed on FaceBook.