Heart disease and stroke are two of the leading causes of death and disability and for people who have experienced either their treatment options are very limited. Current therapies focus on dealing with the immediate impact of the attack, but there is nothing to deal with the longer-term impact. The CIRM Board hopes to change that by funding promising work for both conditions.
Dr. Gary Steinberg and his team at Stanford were awarded almost $12 million to conduct a clinical trial to test a therapy for motor disabilities caused by chronic ischemic stroke. While “clot busting” therapies can treat strokes in their acute phase, immediately after they occur, these treatments can only be given within a few hours of the initial injury. There are no approved therapies to treat chronic stroke, the disabilities that remain in the months and years after the initial brain attack.
Dr. Steinberg will use embryonic stem cells that have been turned into neural stem cells (NSCs), a kind of stem cell that can form different cell types found in the brain. In a surgical procedure, the team will inject the NSCs directly into the brains of chronic stroke patients. While the ultimate goal of the therapy is to restore loss of movement in patients, this is just the first step in clinical trials for the therapy. This first-in-human trial will evaluate the therapy for safety and feasibility and look for signs that it is helping patients.
Another Stanford researcher, Dr. Crystal Mackall, was also awarded almost $12 million to conduct a clinical trial to test a treatment for children and young adults with glioma, a devastating, aggressive brain tumor that occurs primarily in children and young adults and originates in the brain. Such tumors are uniformly fatal and are the leading cause of childhood brain tumor-related death. Radiation therapy is a current treatment option, but it only extends survival by a few months.
Dr. Crystal Mackall and her team will modify a patient’s own T cells, an immune system cell that can destroy foreign or abnormal cells. The T cells will be modified with a protein called chimeric antigen receptor (CAR), which will give the newly created CAR-T cells the ability to identify and destroy the brain tumor cells. The CAR-T cells will be re-introduced back into patients and the therapy will be evaluated for safety and efficacy.
Stanford made it three in a row with the award of almost $7 million to Dr. Joe Wu to test a therapy for left-sided heart failure resulting from a heart attack. The major issue with this disease is that after a large number of heart muscle cells are killed or damaged by a heart attack, the adult heart has little ability to repair or replace these cells. Thus, rather than being able to replenish its supply of muscle cells, the heart forms a scar that can ultimately cause it to fail.
Dr. Wu will use human embryonic stem cells (hESCs) to generate cardiomyocytes (CM), a type of cell that makes up the heart muscle. The newly created hESC-CMs will then be administered to patients at the site of the heart muscle damage in a first-in-human trial. This initial trial will evaluate the safety and feasibility of the therapy, and the effect upon heart function will also be examined. The ultimate aim of this approach is to improve heart function for patients suffering from heart failure.
“We are pleased to add these clinical trials to CIRM’s portfolio,” says Maria T. Millan, M.D., President and CEO of CIRM. “Because of the reauthorization of CIRM under Proposition 14, we have now directly funded 75 clinical trials. The three grants approved bring forward regenerative medicine clinical trials for brain tumors, stroke, and heart failure, debilitating and fatal conditions where there are currently no definitive therapies or cures.”
In late March the CIRM Board approved $5 million in emergency funding for COVID-19 research. The idea was to support great ideas from California’s researchers, some of which had already been tested for different conditions, and see if they could help in finding treatments or a vaccine for the coronavirus.
Less than a month later we were funding a clinical trial and two other projects, one that targeted a special kind of immune system cell that has the potential to fight the virus.
Researchers use stem cells to model the immune response to COVID-19
By Tiare Dunlap
Cities across the United States are opening back up, but we’re still a long way from making the COVID-19 pandemic history. To truly accomplish that, we need to have a vaccine that can stop the spread of infection.
But to develop an effective vaccine, we need to understand how the immune system responds to SARS-CoV-2, the virus that causes COVID-19.
Vaccines work by imitating infection. They expose a person’s immune system to a weakened version or component of the virus they are intended to protect against. This essentially prepares the immune system to fight the virus ahead of time, so that if a person is exposed to the real virus, their immune system can quickly recognize the enemy and fight the infection. Vaccines need to contain the right parts of the virus to provoke a strong immune response and create long-term protection.
Most of the vaccines in development for SARS CoV-2 are using part of the virus to provoke the immune system to produce proteins called antibodies that neutralize the virus. Another way a vaccine could create protection against the virus is by activating the T cells of the immune system.
T cells specifically “recognize” virus-infected cells, and these kinds of responses may be especially important for providing long-term protection against the virus. One challenge for researchers is that they have only had a few months to study how the immune system protects against SARS CoV-2, and in particular, which parts of the virus provoke the best T-cell responses.
For years, they have been perfecting an innovative technology that uses blood-forming stem cells — which can give rise to all types of blood and immune cells — to produce a rare and powerful subset of immune cells called type 1 dendritic cells. Type 1 dendritic cells play an essential role in the immune response by devouring foreign proteins, termed antigens, from virus-infected cells and then chopping them into fragments. Dendritic cells then use these protein fragments to trigger T cells to mount an immune response.
Using this technology, Crooks and Seet are working to pinpoint which specific parts of the SARS-CoV-2 virus provoke the strongest T-cell responses.
Building long-lasting immunity
“We know from a lot of research into other viral infections and also in cancer immunotherapy, that T-cell responses are really important for long-lasting immunity,” said Seet, an assistant professor of hematology-oncology at the David Geffen School of Medicine at UCLA. “And so this approach will allow us to better characterize the T-cell response to SARS-CoV-2 and focus vaccine and therapeutic development on those parts of the virus that induce strong T-cell immunity.”
Crooks’ and Seet’s project uses blood-forming stem cells taken from healthy donors and infected with a virus containing antigens from SARS-CoV-2. They then direct these stem cells to produce large numbers of type 1 dendritic cells using a new method developed by Seet and Suwen Li, a graduate student in Crooks’ lab. Both Seet and Li are graduates of the UCLA Broad Stem Cell Research Center’s training program.
“The dendritic cells we are able to make using this process are really good at chopping up viral antigens and eliciting strong immune responses from T cells,” said Crooks, a professor of pathology and laboratory medicine and of pediatrics at the medical school and co-director of the UCLA Broad Stem Cell Research Center.
When type 1 dendritic cells chop up viral antigens into fragments, they present these fragments on their cell surfaces to T cells. Our bodies produce millions and millions of T cells each day, each with its own unique antigen receptor, however only a few will have a receptor capable of recognizing a specific antigen from a virus.
When a T cell with the right receptor recognizes a viral antigen on a dendritic cell as foreign and dangerous, it sets off a chain of events that activates multiple parts of the immune system to attack cells infected with the virus. This includes clonal expansion, the process by which each responding T cell produces a large number of identical cells, called clones, which are all capable of recognizing the antigen.
“Most of those T cells will go off and fight the infection by killing cells infected with the virus,” said Seet, who, like Crooks, is also a member of the UCLA Jonsson Comprehensive Cancer Center. “However, a small subset of those cells become memory T cells — long-lived T cells that remain in the body for years and protect from future infection by rapidly generating a robust T-cell response if the virus returns. It’s immune memory.”
Producing extremely rare immune cells
This process has historically been particularly challenging to model in the lab, because type 1 dendritic cells are extremely rare — they make up less than 0.1% of cells found in the blood. Now, with this new stem cell technology, Crooks and Seet can produce large numbers of these dendritic cells from blood stem cells donated by healthy people, introduce them to parts of the virus, then see how T cells taken from the blood can respond in the lab. This process can be repeated over and over using cells taken from a wide range of healthy people.
“The benefit is we can do this very quickly without the need for an actual vaccine trial, so we can very rapidly figure out in the lab which parts of the virus induce the best T-cell responses across many individuals,” Seet said.
The resulting data could be used to inform the development of new vaccines for COVID-19 that improve T-cell responses. And the data about which viral antigens are most important to the T cells could also be used to monitor the effectiveness of existing vaccine candidates, and an individual’s immune status to the virus.
“There are dozens of vaccine candidates in development right now, with three or four of them already in clinical trials,” Seet said. “We all hope one or more will be effective at producing immediate and long-lasting immunity. But as there is so much we don’t know about this new virus, we’re still going to need to really dig in to understand how our immune systems can best protect us from infection.”
Supporting basic research into our body’s own processes that can inform new strategies to fight disease is central to the mission of the Broad Stem Cell Research Center.
“When we started developing this project some years ago, we had no idea it would be so useful for studying a viral infection, any viral infection,” Crooks said. “And it was only because we already had these tools in place that we could spring into action so fast.”
Our immune system is the first line of defense our bodies use to fight off infections and disease. One crucial component of this defense mechanism are lymphocytes, which are specialized cells that give rise to various kinds of immune cells, such as a T cell, designed to attack and destroy harmful foreign bodies. Problems in how certain immune cells are formed can lead to diseases such as leukemia and other immune system related disorders.
But how exactly do immune cells form early on in the body?
Dr. Andrew Elfanty and Dr. Ed Stanley at Murdoch Children’s Research Institute in Australia have reproduced and visualized a method in the laboratory used to create human immune cells from pluripotent stem cells, a kind of stem cell that can make virtually any kind of cell in the body. Not only can this unlock a better understanding of leukemia and other immune related diseases, it could potentially lead to a patient’s own skin cells being used to produce new cells for cancer immunotherapy or to test autoimmune disease therapies.
Dr. Elefanty and Dr. Stanley used genetic engineering and a unique way of growing stem cells to make this discovery.
As observed in this video, the team was able to engineer pluripotent stem cells to glow green when they expressed a specific protein found in early immune cells. These cells can be seen migrating along blood vessels outlined in red. These cells go on to populate the thymus, which as we discussed in an earlier blog, is an organ that is crucial in developing functional T cells.
In a press release from Murdoch Children’s Research Institute, Dr. Stanley talks about the important role these early immune cells might play.
“We think these early cells might be important for the correct maturation of the thymus, the organ that acts as a nursery for T-cells”
In addition to this, the team also isolated the green, glowing pluripotent stem cells and showed that they could be used for multiple immune cell types, including those necessary for shaping the development of the immune system as a whole.
In the same press release, Dr. Elefanty discusses the future direction that their research could lead to.
“Although a clinical application is likely still years away, we can use this new knowledge to test ideas about how diseases like childhood leukemia and type 1 diabetes develop. Understanding more about the steps these cells go through, and how we can more efficiently nudge them down a desired pathway, is going to be crucial to that process.”
The full results to this study were published in Nature Cell Biology.
Last week we shared a powerful story of patient advocate Taylor Lookofsky,a young man with IPEX syndrome. In his speech, he talked about the impact the condition has had on his life. Taylor shared this speech a few weeks ago right after the CIRM Board awarded $5.53 million to Dr. Rosa Bacchetta for her work related to IPEX syndrome.
But this begs the question, what exactly is IPEX syndrome? What is the approach that Dr. Bacchetta is working on? For those of you interested in the deeper scientific dive, we will elaborate on this complex disease and promising approach.
IPEX syndrome is a rare disease that primarily affects males and is caused by a genetic mutation that leads to a lack of specialized immune cells called regulatory T cells (Tregs).
Without the presence of Tregs, a patient’s own immune cells attack the body’s own tissues and organs, a phenomenon known as autoimmunity. This affects many different areas such as the intestines, skin, and hormone-producing glands and can be fatal in early childhood.
Current treatment options include a bone marrow transplant and immune suppressing drugs. However, immune suppression is only partially effective and can cause severe side effects while bone marrow transplants are limited due to lack of matching donors.
Dr. Rosa Bacchetta and her team at Stanford will take a patient’s own blood in order to obtain CD4+ T cells. Then, using gene therapy, they will insert a normal version of the mutated gene into the CD4+ T cells, allowing them to function like normal Treg cells. These Treg-like cells would then be reintroduced back into the patient, hopefully creating an IPEX-free blood supply and correcting the problem.
Furthermore, if successful, this treatment could be adapted for treatment of other autoimmune conditions where Treg cells are underlying problem.
The goal of this work is to complete the work necessary to conduct a clinical trial for IPEX syndrome.
The governing Board of the California Institute for Regenerative Medicine (CIRM) yesterday invested $32.92 million to fund the Stem Cell Agency’s first clinical trial in Parkinson’s disease (PD), and to support three clinical trials targeting different forms of vision loss.
This brings the total number of clinical trials funded by CIRM to 60.
The PD trial will be carried out by Dr. Krystof Bankiewicz at Brain Neurotherapy Bio, Inc. He is using a gene therapy approach to promote the production of a protein called GDNF, which is best known for its ability to protect dopaminergic neurons, the kind of cell damaged by Parkinson’s. The approach seeks to increase dopamine production in the brain, alleviating PD symptoms and potentially slowing down the disease progress.
David Higgins, PhD, a CIRM Board member and patient advocate for Parkinson’s says there is a real need for new approaches to treating the disease. In the US alone, approximately 60,000 people are diagnosed with PD each year and it is expected that almost one million people will be living with the disease by 2020.
“Parkinson’s Disease is a serious unmet medical need and, for reasons we don’t fully understand, its prevalence is increasing. There’s always more outstanding research to fund than there is money to fund it. The GDNF approach represents one ‘class’ of potential therapies for Parkinson’s Disease and has the potential to address issues that are even broader than this specific therapy alone.”
The Board also approved funding for two clinical trials targeting retinitis pigmentosa (RP), a blinding eye disease that affects approximately 150,000 individuals in the US and 1.5 million people around the world. It is caused by the destruction of light-sensing cells in the back of the eye known as photoreceptors. This leads to gradual vision loss and eventually blindness. There are currently no effective treatments for RP.
Dr. Henry Klassen and his team at jCyte are injecting human retinal progenitor cells (hRPCs), into the vitreous cavity, a gel-filled space located in between the front and back part of the eye. The proposed mechanism of action is that hRPCs secrete neurotrophic factors that preserve, protect and even reactivate the photoreceptors, reversing the course of the disease.
CIRM has supported early development of Dr. Klassen’s approach as well as preclinical studies and two previous clinical trials. The US Food and Drug Administration (FDA) has granted jCyte Regenerative Medicine Advanced Therapy (RMAT) designation based on the early clinical data for this severe unmet medical need, thus making the program eligible for expedited review and approval.
The other project targeting RP is led by Dr. Clive Svendsen from the Cedars-Sinai Regenerative Medicine Institute. In this approach, human neural progenitor cells (hNPCs) are transplanted to the back of the eye of RP patients. The goal is that the transplanted hNPCs will integrate and create a protective layer of cells that prevent destruction of the adjacent photoreceptors.
The third trial focused on vision destroying diseases is led by Dr. Sophie Deng at the University of California Los Angeles (UCLA). Dr. Deng’s clinical trial addresses blinding corneal disease by targeting limbal stem cell deficiency (LSCD). Under healthy conditions, limbal stem cells (LSCs) continuously regenerate the cornea, the clear front surface of the eye that refracts light entering the eye and is responsible for the majority of the optical power. Without adequate limbal cells , inflammation, scarring, eye pain, loss of corneal clarity and gradual vision loss can occur. Dr. Deng’s team will expand the patient’s own remaining LSCs for transplantation and will use novel diagnostic methods to assess the severity of LSCD and patient responses to treatment. This clinical trial builds upon previous CIRM-funded work, which includes early translational and late stage preclinical projects.
“CIRM funds and accelerates promising early stage research, through development and to clinical trials,” says Maria T. Millan, MD, President and CEO of CIRM. “Programs, such as those funded today, that were novel stem cell or gene therapy approaches addressing a small number of patients, often have difficulty attracting early investment and funding. CIRM’s role is to de-risk these novel regenerative medicine approaches that are based on rigorous science and have the potential to address unmet medical needs. By de-risking programs, CIRM has enabled our portfolio programs to gain significant downstream industry funding and partnership.”
CIRM Board also awarded $5.53 million to Dr. Rosa Bacchetta at Stanford to complete work necessary to conduct a clinical trial for IPEX syndrome, a rare disease caused by mutations in the FOXP3 gene. Immune cells called regulatory T Cells normally function to protect tissues from damage but in patients with IPEX syndrome, lack of functional Tregs render the body’s own tissues and organs to autoimmune attack that could be fatal in early childhood. Current treatment options include a bone marrow transplant which is limited by available donors and graft versus host disease and immune suppressive drugs that are only partially effective. Dr. Rosa Bacchetta and her team at Stanford will use gene therapy to insert a normal version of the FOXP3 gene into the patient’s own T Cells to restore the normal function of regulatory T Cells.
The CIRM 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.
The TRAN1 Awards are summarized in the table below:
Ex Vivo Gene Editing of Human Hematopoietic Stem Cells for the Treatment of X-Linked Hyper IgM Syndrome
BCMA/CS1 Bispecific CAR-T Cell Therapy to Prevent Antigen Escape in Multiple Myeloma
Neural Stem cell-mediated oncolytic immunotherapy for ovarian cancer
City of Hope
Development of a human stem cell-derived inhibitory neuron therapeutic for the treatment of chronic focal epilepsy
Growing up I loved watching old cowboy movies. Invariably the hero, even though mortally wounded, would manage to save the day and rescue the heroine and/or the town.
Now it seems some stem cells perform the same function, dying in order to save the lives of others.
Researchers at Kings College in London were trying to better understand Graft vs Host Disease (GvHD), a potentially fatal complication that can occur when a patient receives a blood stem cell transplant. In cases of GvHD, the transplanted donor cells turn on the patient and attack their healthy cells and tissues.
Some previous research had found that using bone marrow cells called mesenchymal stem cells (MSCs) had some success in combating GvHD. But it was unpredictable who it helped and why.
Working with mice, the Kings College team found that the MSCs were only effective if they died after being transplanted. It appears that it is only as they are dying that the MSCs engage with the individual’s immune system, telling it to stop attacking healthy tissues. The team also found that if they kill the MSCs just before transplanting them into mice, they were just as effective.
In a news article on HealthCanal, lead researcher Professor Francesco Dazzi, said the next step is to see if this will apply to, and help, people:
“The side effects of a stem cell transplant can be fatal and this factor is a serious consideration in deciding whether some people are suitable to undergo one. If we can be more confident that we can control these lethal complications in all patients, more people will be able to receive this life saving procedure. The next step will be to introduce clinical trials for patients with GvHD, either using the procedure only in patients with immune systems capable of killing mesenchymal stem cells, or killing these cells before they are infused into the patient, to see if this does indeed improve the success of treatment.”
When functioning properly, the T cells of our immune system keep us healthy by detecting and killing off infected, damaged or cancerous cells in our body. But in the case of type 1 diabetes, a person’s own T cells turn against the body by mistakenly targeting and destroying perfectly normal islet cells in the pancreas, which are responsible for producing insulin. As a result, the insulin-dependent delivery of blood sugar to the energy-hungry organs is disrupted leading to many serious complications. Blood stem cell transplants have been performed to treat the disease by attempting to restart the immune system. The results have failed to provide a cure.
Now a new study, published in Science Translational Medicine, appears to explain why those previous attempts failed and how some genetic rejiggering could lead to a successful treatment for type 1 diabetes.
An analysis of the gene activity inside the blood stem cells of diabetic mice and humans reveals that these cells lack a protein called PD-L1. This protein is known to play an important role in putting the brakes on T cell activity. Because T cells are potent cell killers, it’s important for proteins like PD-L1 to keep the activated T cells in check.
Credit: Andrea Panigada/Nancy Fliesler
Researchers from Boston Children’s Hospital hypothesized that adding back PD-L1 may prevent T cells from the indiscriminate killing of the body’s own insulin-producing cells. To test this idea, the research team genetically engineered mouse blood stem cells to produce the PD-L1 protein. Experiments with the cells in a petri dish showed that the addition of PD-L1 did indeed block the attack-on-self activity. And when these blood stem cells were transplanted into a diabetic mouse strain, the disease was reversed in most of the animals over the short term while a third of the mice had long-lasting benefits.
The researchers hope this targeting of PD-L1 production – which the researchers could also stimulate with pharmacological drugs – will contribute to a cure for type 1 diabetes.
FDA’s new guidelines for stem cell treatments
FDA Commissioner Scott Gottlieb
Yesterday Scott Gottlieb, the Commissioner at the US Food and Drug Administration (FDA), laid out some new guidelines for the way the agency regulates stem cells and regenerative medicine. The news was good for patients, not so good for clinics offering unproven treatments.
First the good. Gottlieb announced new guidelines encouraging innovation in the development of stem cell therapies, and faster pathways for therapies, that show they are both safe and effective, to reach the patient.
At the same time, he detailed new rules that provide greater clarity about what clinics can do with stem cells without incurring the wrath of the FDA. Those guidelines detail the limits on the kinds of procedures clinics can offer and what ways they can “manipulate” those cells. Clinics that go beyond those limits could be in trouble.
In making the announcement Gottlieb said:
“To be clear, we remain committed to ensuring that patients have access to safe and effective regenerative medicine products as efficiently as possible. We are also committed to making sure we take action against products being unlawfully marketed that pose a potential significant risk to their safety. The framework we’re announcing today gives us the solid platform we need to continue to take enforcement action against a small number of clearly unscrupulous actors.”
Many of the details in the announcement match what CIRM has been pushing for some years. Randy Mills, our previous President and CEO, called for many of these changes in an Op Ed he co-wrote with former US Senator Bill Frist.
Our hope now is that the FDA continues to follow this promising path and turns these draft proposals into hard policy.
Every day at CIRM we get calls from people looking for a stem cell therapy to help them fight a life-threatening or life-altering disease or condition. One of the most common calls is about osteoarthritis, a painful condition where the cartilage that helps cushion our joints is worn away, leaving bone to rub on bone. People call asking if we have something, anything, that might be able to help them. Now we do.
At yesterday’s CIRM Board meeting the Independent Citizens’ Oversight Committee or ICOC (the formal title of the Board) awarded almost $8.5 million to the California Institute for Biomedical Research (CALIBR) to test a drug that appears to help the body regenerate cartilage. In preclinical tests the drug, KA34, stimulated mesenchymal stem cells to turn into chondrocytes, the kind of cell found in healthy cartilage. It’s hoped these new cells will replace those killed off by osteoarthritis and repair the damage.
This is a Phase 1 clinical trial where the goal is primarily to make sure this approach is safe in patients. If the treatment also shows hints it’s working – and of course we hope it will – that’s a bonus which will need to be confirmed in later stage, and larger, clinical trials.
From a purely selfish perspective, it will be nice for us to be able to tell callers that we do have a clinical trial underway and are hopeful it could lead to an effective treatment. Right now the only alternatives for many patients are powerful opioids and pain killers, surgery, or turning to clinics that offer unproven stem cell therapies.
Targeting immune system cancer
The CIRM Board also awarded Poseida Therapeutics $19.8 million to target multiple myeloma, using the patient’s own genetically re-engineered stem cells. Multiple myeloma is caused when plasma cells, which are a type of white blood cell found in the bone marrow and are a key part of our immune system, turn cancerous and grow out of control.
As Dr. Maria Millan, CIRM’s President & CEO, said in a news release:
“Multiple myeloma disproportionately affects people over the age of 65 and African Americans, and it leads to progressive bone destruction, severe anemia, infectious complications and kidney and heart damage from abnormal proteins produced by the malignant plasma cells. Less than half of patients with multiple myeloma live beyond 5 years. Poseida’s technology is seeking to destroy these cancerous myeloma cells with an immunotherapy approach that uses the patient’s own engineered immune system T cells to seek and destroy the myeloma cells.”
In a news release from Poseida, CEO Dr. Eric Ostertag, said the therapy – called P-BCMA-101 – holds a lot of promise:
“P-BCMA-101 is elegantly designed with several key characteristics, including an exceptionally high concentration of stem cell memory T cells which has the potential to significantly improve durability of response to treatment.”
The third clinical trial funded by the Board yesterday also uses T cells. Researchers at Children’s Hospital of Los Angeles were awarded $4.8 million for a Phase 1 clinical trial targeting potentially deadly infections in people who have a weakened immune system.
Viruses such as cytomegalovirus, Epstein-Barr, and adenovirus are commonly found in all of us, but our bodies are usually able to easily fight them off. However, patients with weakened immune systems resulting from chemotherapy, bone marrow or cord blood transplant often lack that ability to combat these viruses and it can prove fatal.
The researchers are taking T cells from healthy donors that have been genetically matched to the patient’s immune system and engineered to fight these viruses. The cells are then transplanted into the patient and will hopefully help boost their immune system’s ability to fight the virus and provide long-term protection.
Whenever you can tell someone who calls you, desperately looking for help, that you have something that might be able to help them, you can hear the relief on the other end of the line. Of course, we explain that these are only early-stage clinical trials and that we don’t know if they’ll work. But for someone who up until that point felt they had no options and, often, no hope, it’s welcome and encouraging news that progress is being made.
CIRM Board meeting with Jake Javier, CIRM Chair Jonathan Thomas, Vice Chair Sen. Art Torres (Ret.) and President/CEO Randy Mills
It’s traditional to end the year with a look back at what you hoped to accomplish and an assessment of what you did. By that standard 2016 has been a pretty good year for us at CIRM.
Yesterday our governing Board approved funding for two new clinical trials, one to help kidney transplant patients, the second to help people battling a disease that destroys vision. By itself that is a no small achievement. Anytime you can support potentially transformative research you are helping advance the field. But getting these two clinical trials over the start line means that CIRM has also met one of its big goals for the year; funding ten new clinical trials.
If you had asked us back in the summer, when we had funded only two clinical trials in 2016, we would have said that the chances of us reaching ten trials by the end of the year were about as good as a real estate developer winning the White House. And yet……..
Helping kidney transplant recipients
The Board awarded $6.65 million to researchers at Stanford University who are using a deceptively simple approach to help people who get a kidney transplant. Currently people who get a transplant have to take anti-rejection medications for the rest of their life to prevent their body rejecting the new organ. These powerful immunosuppressive medications are essential but also come with a cost; they increase the risk of cancer, infection and heart disease.
CIRM President/CEO Randy Mills addresses the CIRM Board
The Stanford team will see if it can help transplant patients bypass the need for those drugs by injecting blood stem cells and T cells (which play an important role in the immune system) from the kidney donor into the kidney recipient. The hope is by using cells from the donor, you can help the recipient’s body more readily adjust to the new organ and reduce the likelihood the body’s immune system will attack it.
This would be no small feat. Every year around 17,000 kidney transplants take place in the US, and many people who get a donor kidney experience fevers, infections and other side effects as a result of taking the anti-rejection medications. This clinical trial is a potentially transformative approach that could help protect the integrity of the transplanted organ, and improve the quality of life for the kidney recipient.
The second trial approved for funding is one we are already very familiar with; Dr. Henry Klassen and jCyte’s work in treating retinitis pigmentosa (RP). This is a devastating disease that typically strikes before age 30 and slowly destroys a person’s vision. We’ve blogged about it here and here.
Dr. Klassen, a researcher at UC Irvine, has developed a method of injecting what are called retinal progenitor cells into the back of the eye. The hope is that these cells will repair and replace the cells damaged by RP. In a CIRM-funded Phase 1 clinical trial the method proved safe with no serious side effects, and some of the patients also reported improvements in their vision. This raised hopes that a Phase 2 clinical trial using a larger number of cells in a larger number of patients could really see if this therapy is as promising as we hope. The Board approved almost $8.3 million to support that work.
Seeing is believing
How promising? Well, I recently talked to Rosie Barrero, who took part in the first phase clinical trial. She told me that she was surprised how quickly she started to notice improvements in her vision:
“There’s more definition, more colors. I am seeing colors I haven’t seen in years. We have different cups in our house but I couldn’t really make out the different colors. One morning I woke up and realized ‘Oh my gosh, one of them is purple and one blue’. I was by myself, in tears, and it felt amazing, unbelievable.”
Amazing was a phrase that came up a lot yesterday when we introduced four people to our Board. Each of the four had taken part in a stem cell clinical trial that changed their lives, even saved their lives. It was a very emotional scene as they got a chance to thank the group that made those trials, those treatments possible.
Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.
Directing the creation of T cells. To paraphrase the GOP Presidential nominee, any sane person LOVES, LOVES LOVES their T cells, in a HUGE way, so HUGE. They scamper around the body getting rid of viruses and the tiny cancers we all have in us all the time. A CIRM-funded team at CalTech has worked out the steps our genetic machinery must take to make more of them, a first step in letting physicians turn up the action of our immune systems.
We have known for some time the identity of the genetic switch that is the last, critical step in turning blood stem cells into T cells, but nothing in our body is as simple as a single on-off event. The Caltech team isolated four genetic factors in the path leading to that main switch and, somewhat unsuspected, they found out those four steps had to be activated sequentially, not all at the same time. They discovered the path by engineering mouse cells so that the main T cell switch, Bcl11b, glows under a microscope when it is turned on.
“We identify the contributions of four regulators of Bcl11b, which are all needed for its activation but carry out surprisingly different functions in enabling the gene to be turned on,” said Ellen Rothenberg, the senior author in a university press release picked up by Innovations Report. “It’s interesting–the gene still needs the full quorum of transcription factors, but we now find that it also needs them to work in the right order.”
Video primer on stem cells in the brain. In conjunction with an article in its August issue, Scientific Americanposted a video from the Brain Forum in Switzerland of Elena Cattaneo of the University of Milan explaining the basics of adult versus pluripotent stem cells, and in particular how we are thinking about using them to repair diseases in the brain.
The 20-minute talk gives a brief review of pioneers who “stood alone in unmarked territory.” She asks how can stem cells be so powerful; and answers by saying they have lots of secrets and those secrets are what stem cell scientist like her are working to unravel. She notes stem cells have never seen a brain, but if you show them a few factors they can become specialized nerves. After discussing collaborations in Europe to grow replacement dopamine neurons for Parkinson’s disease, she went on to describe her own effort to do the same thing in Huntington’s disease, but in this case create the striatal nerves lost in that disease.
The video closes with a discussion of how basic stem cell research can answer evolutionary questions, in particular how genetic changes allowed higher organisms to develop more complex nervous systems.
CIRM Science Officers Kelly Shepard and Kent Fitzgerald
A stem cell review that hits close to home. IEEE Pulse, a publication for scientists who mix engineering and medicine and biology, had one of their reporters interview two of our colleagues on CIRM’s science team. They asked senior science officers Kelly Shepard and Kent Fitzgerald to reflect on how the stem cell field has progressed based on their experience working to attract top researchers to apply for our grants and watching our panel of outside reviewers select the top 20 to 30 percent of each set of applicants.
One of the biggest changes has been a move from animal stem cell models to work with human stem cells, and because of CIRM’s dedicated and sustained funding through the voter initiative Proposition 71, California scientists have led the way in this change. Kelly described examples of how mouse and human systems are different and having data on human cells has been critical to moving toward therapies.
Kelly and Kent address several technology trends. They note how quickly stem cell scientists have wrapped their arms around the new trendy gene editing technology CRISPR and discuss ways it is being used in the field. They also discuss the important role of our recently developed ability to perform single cell analysis and other technologies like using vessels called exosomes that carry some of the same factors as stem cells without having to go through all the issues around transplanting whole cells.
“We’re really looking to move things from discovery to the clinic. CIRM has laid the foundation by establishing a good understanding of mechanistic biology and how stem cells work and is now taking the knowledge and applying it for the benefit of patients,” Kent said toward the end of the interview.
Jake Javier and his family
Jake’s story: one young man’s journey to and through a stem cell transplant; As a former TV writer and producer I tend to be quite critical about the way TV news typically covers medical stories. But a recent story on KTVU, the Fox News affiliate here in the San Francisco Bay Area, showed how these stories can be done in a way that balances hope, and accuracy.
Reporter Julie Haener followed the story of Jake Javier – we have blogged about Jake before – a young man who broke his spine and was then given a stem cell transplant as part of the Asterias Biotherapeutics clinical trial that CIRM is funding.
It’s a touching story that highlights the difficulty treating these injuries, but also the hope that stem cell therapies holds out for people like Jake, and of course for his family too.
If you want to see how a TV story can be done well, this is a great example.
Imagine if scientists could build microscopic smart missiles that specifically seek out and destroy deadly, hard-to-treat cancer cells in a patient’s body? Well, you don’t have to imagine it actually. With techniques such as chimeric antigen receptor (CAR) T therapy, a patient’s own T cells – immune system cells that fight off viruses and cancer cells – can be genetically modified to produce customized cell surface proteins to recognize and kill the specific cancer cells eluding the patient’s natural defenses. It is one of the most exciting and promising techniques currently in development for the treatment of cancer.
Human T Cell (Wikipedia)
Although there have been several clinical trial success stories, it’s still early days for engineered T cell immunotherapies and much more work is needed to fine tune the approach as well as overcome potential dangerous side effects. Taking a step back and gaining a deeper understanding of how stem cells specialize into T cells in the first place could go a long way into increasing the efficiency and precision of this therapeutic strategy.
Enter the CIRM-funded work of Hao Yuan Kueh and others in Ellen Rothenberg’s lab at CalTech. Reporting yesterday in Nature Immunology, the Rothenberg team uncovered a time dependent array of genetic switches – some with an ON/OFF function, others with “volume” control – that together control the commitment of stem cells to become T cells.
Previous studies have shown that the protein encoded by the Bcl11b gene is the key master switch that when activated sets a “no going back” path toward a T cell fate. A group of other genes, including Runx1, TCF-1 and GATA-3 are known to play a role in activating Bcl11b. The dominant school of thought is that these proteins gradually accumulate at the Bcl11b gene and once a threshold level is achieved, the proteins combine to enable the Bcl11b activation switch to flip on. However, other studies suggest that some of these proteins may act as “pioneer” factors that loosen up the DNA structure and allow the other proteins to readily access and turn on the Bcl11b gene. Figuring out which mechanism is at play is critical to precisely manipulating T cell development through genetic engineering.
To tease out the answer, the CalTech team engineered mice such that cells with activated Bcl11b would glow which allows visualizing the fate of single cells. We reached out to Dr. Kueh on the rationale for this experimental approach:
Hao Yuan Kueh, CalTech
“To fully understand how genes are controlled, we need to watch them turn on and off in single, living cells over time. As cells in our body are unique and different from one another, standard measurement methods, which average over millions of cells, often do not tell us the entire picture.”
The team examined the impact of inhibiting the T cell specific proteins GATA-3 and TCF-1 at different stages in T cell development in single cells. When the production of these two proteins were blocked in very early T cell progenitor (ETPs) cells, activation of Bcl11b was dramatically reduced. But that’s not what they observed when the experiment was repeated in a later stage of T cell development. In this case, blocking GATA-3 and TCF-1 had a much weaker impact on Bcl11b. So GATA-3 and TCF-1 are important for turning on Bcl11b early in T cell development but are not necessary for maintaining Bcl11b activation at later stages.
Inhibition of Runx1, on the other hand, did lead to a reduction in Bcl11b in these later T cell development stages. Making Runx1 levels artificially high conversely led to elevated Bcl11b in these cells.
Together, these results point to GATA-3 and TCF-1 as the key factors for turning on Bcl11b to commit cells to a T cell fate and then they hand off their duties to Runx1 to keep Bcl11b on and maintaining the T cell identity. Dr. Kuhn sums up the results and their implications this way:
“Our work shows that control of gene expression is very much a team effort, where some proteins flip the gene’s master ON-OFF switch, and others set its expression levels after it turns on…These results will help us generate customized T-cells to fight cancer and other diseases. As T-cells are specialized to recognize and fight foreign agents in our body, this therapy strategy holds much promise for diseases that are difficult to treat with standard drug-based methods. Also, these intricate gene regulation mechanisms are likely to be in play in other cell types in our body, not just T-cells, and so we believe our results will be widely relevant.”