Stem cell stories that caught our eye: the tale of a tail that grows back and Zika’s devious Trojan Horse

The tale of a tail that grows back (Kevin McCormack)

Ask people what they know about geckos and the odds are they’ll tell you geckos have English accents and sell car insurance. Which tells you a lot more about the power of advertising than it does about the level of knowledge about lizards. Which is a shame, because the gecko has some amazing qualities, not the least of which is its ability to re-grow its tail. Now some researchers have discovered how it regenerates its tail, and what they’ve learned could one day help people with spinal cord injuries.

Geckos often detach a bit of their tail when being pursued by a predator, then grow a new one over the course of 30 days. Researchers at the University of Guelph in Canada found that the lizards use a combination of stem cells and proteins to do that.

They found that geckos have stem cells in their tail called radial glias. Normally these cells are dormant but that changes when the lizard loses its tail. As Matthew Vickaryous, lead author of the study, said in a news release:

“But when the tail comes off everything temporarily changes. The cells make different proteins and begin proliferating more in response to the injury. Ultimately, they make a brand new spinal cord. Once the injury is healed and the spinal cord is restored, the cells return to a resting state.”

Vickaryous hopes that understanding how the gecko can repair what is essentially an injury to its spinal cord, we’ll be better able to develop ways to help people with the same kind of injury.

The study is published in the Journal of Comparative Neurology.

Zika virus uses Trojan Horse strategy to infect developing brain
In April 2015, the World Health Organization declared that infection by Zika virus and its connection to severe birth defects was an international public health emergency. The main concern has been the virus’ link to microcephaly, a condition in which abnormal brain development causes a smaller than normal head size at birth. Microcephaly leads to number of problems in these infants including developmental delays, seizures, hearing loss and difficulty swallowing.

A false color micrograph shows microglia cells (green) infected by the Zika virus (blue). Image Muotri lab/UCSD

Since that time, researchers have been racing to better understand how Zika infection affects brain development with the hope of finding treatment strategies. Now, a CIRM-funded study in Human Molecular Genetics reports important new insights about how Zika virus may be transmitted from infected pregnant women to their unborn babies.

The UCSD researchers behind the study chose to focus on microglia cells. In a press release, team leader Alysson Muotri explained their rationale for targeting these cells:

“During embryogenesis — the early stages of prenatal development — cells called microglia form in the yolk sac and then disperse throughout the central nervous system (CNS) of the developing child. Considering the timing of [Zika] transmission, we hypothesized that microglia might be serving as a Trojan horse to transport the virus during invasion of the CNS.”

In the developing brain, microglia continually travel throughout the brain and clear away dead or infected cells. Smuggling itself aboard microglia would give Zika a devious way to slip through the body’s defenses and infect other brain cells. And that’s exactly what Dr. Muotri’s team found.

Using human induced pluripotent stem cells (iPSCs), they generated brain stem cells – the kind found in the developing brain – and in lab dish infected them with Zika virus. When iPSC-derived microglia were added to the infected neural stem cells, the microglia gobbled them up and destroyed them, just as they would do in the brain. But when those microglia were placed next to uninfected brain stem cells, the Zika virus was easily transmitted to those cells. Muotri summed up the results this way:

“Our findings show that the Zika virus can infect these early microglia, sneaking into the brain where they transmit the virus to other brain cells, resulting in the devastating neurological damage we see in some newborns.”

The team went on to show that an FDA-approved drug to treat hepatitis – a liver disease often caused by viral infection – was effective at decreasing the infection of brain stem cells by Zika-carrying microglia. Since these studies were done in petri dishes, more research will be required to confirm that the microglia are a true drug target for stopping the devastating impact of Zika on newborns.

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CIRM stories that caught our eye: UCSD team stops neuromuscular disease in mice, ALS trial enrolls 1st patients and Q&A with CIRM Prez

Ordinarily, we end each week at the Stem Cellar with a few stem cell stories that caught our eye. But, for the past couple of weeks we’ve been busy churning out stories related to our Month of CIRM blog series, which we hope you’ve found enlightening. To round out the series, we present this “caught our eye” blog of CIRM-specific stories from the last half of October.

Stopping neurodegenerative disorder with blood stem cells. (Karen Ring)

CIRM-funded scientists at the UC San Diego School of Medicine may have found a way to treat a progressive neuromuscular disorder called Fredreich’s ataxia (FA). Their research was published last week in the journal Science Translational Medicine.

FA is a genetic disease that attacks the nervous tissue in the spinal cord leading to the loss of sensory nerve cells that control muscle movement. Early on, patients with FA experience muscle weakness and loss of coordination. As the disease progresses, FA can cause scoliosis (curved spine), heart disease and diabetes. 1 in 50,000 Americans are afflicted with FA, and there is currently no effective treatment or cure for this disease.

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In this reconstituted schematic, blood stem cells transplanted in a mouse model of Friedreich’s ataxia differentiate into microglial cells (red) and transfer mitochondrial protein (green) to neurons (blue), preventing neurodegeneration. Image courtesy of Stephanie Cherqui, UC San Diego School of Medicine.

UCSD scientists, led by CIRM grantee Dr. Stephanie Cherqui, found in a previous study that transplanting blood stem and progenitor cells was an effective treatment for preventing another genetic disease called cystinosis in mice. Cherqui’s cystinosis research is currently being funded by a CIRM late stage preclinical grant.

In this new study, the UCSD team was curious to find out whether a similar stem cell approach could also be an effective treatment for FA. The researchers used an FA transgenic mouse model that was engineered to harbor two different human mutations in a gene called FXN, which produces a mitochondrial protein called frataxin. Mutations in FXN result in reduced expression of frataxin, which eventually leads to the symptoms experienced by FA patients.

When they transplanted healthy blood stem and progenitor cells (HSPCs) from normal mice into FA mice, the cells developed into immune cells called microglia and macrophages. They found the microglia in the brain and spinal cord and the macrophages in the spinal cord, heart and muscle tissue of FA mice that received the transplant. These normal immune cells produced healthy frataxin protein, which was transferred to disease-affected nerve and muscle cells in FA mice.

Cherqui explained their study’s findings in a UC San Diego Health news release:

“Transplantation of wildtype mouse HSPCs essentially rescued FA-impacted cells. Frataxin expression was restored. Mitochondrial function in the brains of the transgenic mice normalized, as did in the heart. There was also decreased skeletal muscle atrophy.”

In the news release, Cherqui’s team acknowledged that the FA mouse model they used does not perfectly mimic disease progression in humans. In future studies, the team will test their method on other mouse models of FA to ultimately determine whether blood stem cell transplants will be an effective treatment option for FA patients.

Brainstorm’s CIRM funded clinical trial for ALS enrolls its first patients
“We have been conducting ALS clinical trials for more than two decades at California Pacific Medical Center (CPMC) and this is, by far, the most exciting trial in which we have been involved to date.”

Those encouraging words were spoken by Dr. Robert Miller, director of CPMC’s Forbes Norris ALS Research Center in an October 16th news release posted by Brainstorm Cell Therapeutics. The company announced in the release that they had enrolled the first patients in their CIRM-funded, stem cell-based clinical trial for the treatment of amyotrophic lateral sclerosis (ALS).

BrainStorm

Also known as Lou Gehrig’s disease, ALS is a cruel, devastating disease that gradually destroys motor neurons, the cells in the brain or spinal cord that instruct muscles to move. People with the disease lose the ability to move their muscles and, over time, the muscles atrophy leading to paralysis. Most people with ALS die within 3 to 5 years from the onset of symptoms and there is no effective therapy for the disease.

Brainstorm’s therapy product, called NurOwn®, is made from mesenchymal stem cells that are taken from the patient’s own bone marrow. These stem cells are then modified to boost their production and release of factors, which are known to help support and protect the motor neurons destroyed by the disease. Because the cells are derived directly from the patient, no immunosuppressive drugs are necessary, which avoids potentially dangerous side effects. The trial aims to enroll 200 patients and is a follow up of a very promising phase 2 trial. CIRM’s $16 million grant to the Israeli company which also has headquarters in the United States will support clinical studies at multiple centers in California. And Abla Creasey, CIRM’s Senior Director of Strategic Infrastructure points out in the press release, the Agency support of this trial goes beyond this single grant:

“Brainstorm will conduct this trial at multiple sites in California, including our Alpha Clinics Network and will also manufacture its product in California using CIRM-funded infrastructure.”

An initial analysis of the effectiveness of NurOwn® in this phase 3 trial is expected in 2019.

CIRM President Maria Millan reflects on her career, CIRM’s successes and the outlook for stem cell biology 

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Maria T. Millan, M.D., CIRM President and CEO

RegMedNet a networking website that provides content related to the regenerative medicine community, published an interview this morning with Maria Millan, M.D., CIRM’s new President and CEO. The interview covers the impressive accomplishments that Dr. Millan had achieved before coming to CIRM, with details that even some of us CIRM team members may not have been aware of. In addition to describing her pre-CIRM career, Dr. Millan also describes the Agency’s successes during her term as Vice President of CIRM’s Therapeutics group and she gives her take on future of Agency and the stem cell biology field in general over the next five years and beyond. File this article under “must read”.

The Alpha Stem Cell Clinics: Innovation for Breakthrough Stem Cell Treatments

During this third week of the Month of CIRM, we are focusing on CIRM’s Infrastructure programs which are all focused on helping to accelerate stem cell treatments to patients with unmet medical needs.

So here is the question of the day: What is the world’s largest network of medical centers dedicated to providing stem cell treatments to patients?

The answer is the CIRM Alpha Stem Cell Clinics Network.

The CIRM Alpha Stem Cell Clinics Network consists of leading medical institutions throughout California.

The ASCC Network consists of six leading medical centers throughout California. In 2015, the Network was launched in southern California at the City of Hope, UC Irvine, UC Los Angeles, and UC San Diego. In September 2017, CIRM awarded funding to UC Davis and UC San Francisco to enable the Network to better serve patients throughout the state. Forty stem cell clinical trials have been conducted within the Network with hundreds of patients being treat for a variety of conditions, including:

  • Cancers of the blood, brain, lung and other sites
  • Organ diseases of the heart and kidney
  • Pediatric diseases
  • Traumatic injury to the brain and spine

A complete list of clinical trials may be found on our website.

The Alpha Clinics at UC Los Angeles and San Francisco are working collaboratively on breakthrough treatments for serious childhood diseases. This video highlights a CIRM-funded clinical trial at the UCLA Alpha Clinic that is designed to restore the immune system of patients with life-threatening immune deficiencies. A similar breakthrough treatment is also being used at the UCLA Alpha Clinic to treat sickle cell disease. A video describing this treatment is below.

Why do we need a specialized Network for stem cell clinical trials?

Stem cell treatments are unique in many ways. First, they consist of cells or cell products that frequently require specialized processing. For example, the breakthrough treatments for children, described above, requires the bone marrow to be genetically modified to correct defects. This “gene therapy” is performed in the Alpha Clinic laboratories, which are specifically designed to implement cutting edge gene therapy techniques on the patient’s stem cells.

Many of the cancer clinical trials also take the patient’s own cells and then process them in a laboratory. This processing is designed to enhance the patient’s ability to fight cancer using their own immune cells. Each Alpha Clinic has specialized laboratories to process cells, and the sites at City of Hope and UC Davis have world-class facilities for stem cell manufacturing. The City of Hope and Davis facilities produce high quality therapeutic products for commercial and academic clinical trial sponsors. Because of this ability, the Network has become a prime location internationally for clinical trials requiring processing and manufacturing services.

Another unique feature of the Network is its partnership with CIRM, whose mission is to accelerate stem cell treatments for patients with unmet medical needs. Often, this means developing treatments for rare diseases in which the patient population is comparatively small. For example, there about 40-100 immune deficient children born each year in the United States. We are funding clinical trials to help treat those children. The Network is also treating rare brain and blood cancers.

To find patients that may benefit from these treatments, the Network has developed the capacity to confidentially query over 20 million California patient records. If a good match is found, there is a procedure in place, that is reviewed by an ethics committee, where the patient’s doctor can be notified of the trial and pass that information to the patient. For patients that are interested in learning more, each Alpha Clinic has a Patient Care Coordinator with the job of coordinating the process of educating patients about the trial and assisting them if they choose to participate.

How Can I Learn More?

If you are a patient or a family member and would like to learn more about the CIRM Alpha Clinics, click here. There is contact information for each clinic so you can learn more about specific trials, or you can visit our Alpha Clinics Trials page for a complete list of trials ongoing in the Network.

If you are a patient or a trial sponsor interested in learning more about the services offered through our Alpha Clinics Network, visit our website.

Building California’s stem cell research community, from the ground up

For week three of the Month of CIRM, our topic is infrastructure. What is infrastructure? Read on for a big picture overview and then we’ll fill in the details over the course of the week.

When CIRM was created in 2001, our goal was to grow the stem cell research field in California. But to do that, we first had to build some actual buildings. Since then, our infrastructure programs have taken on many different forms, but all have been focused on a single mission – helping accelerate stem cell research to patients with unmet medical needs.
CIRM_Infrastucture-program-iconScreen Shot 2017-10-16 at 10.58.38 AM

In the early 2000’s, stem cell scientists faced a quandary. President George W. Bush had placed limits on how federal funds could be used for embryonic stem cell research. His policy allowed funding of research involving some existing embryonic stem cell lines, but banned research that developed or conducted research on new stem lines.

Many researchers felt the existing lines were not the best quality and could only use them in a limited capacity. But because they were dependent on the government to fund their work, had no alternative but to comply. Scientists who chose to use non-approved lines were unable to use their federally funded labs for stem cell work.

The creation of CIRM changed that. In 2008, CIRM launched its Major Facilities Grant Program. The program had two major goals:

1) To accommodate the growing numbers of stem cell researchers coming in California as a result of CIRM’s grants and funding.

2) To provide new research space that didn’t have to comply with the federal restrictions on stem cell research.

Over the next few years, the program invested $271million to help build 12 new research facilities around California from Sacramento to San Diego. The institutions used CIRM’s funding to leverage and attract an additional $543 million in funds from private donors and institutions to construct and furnish the buildings.

These world-class laboratories gave scientists the research space they needed to work with any kind of stem cell they wanted and develop new potential therapies. It also enabled the institutions to bring together under one roof, all the stem cell researchers, who previously had been scattered across each campus.

One other important benefit was the work these buildings provided for thousands of construction workers at a time of record unemployment in the industry. Here’s a video about the 12 facilities we helped build:

But building physical facilities was just our first foray into developing infrastructure. We were far from finished.

In the early days of stem cell research, many scientists used cells from different sources, created using different methods. This meant it was often hard to compare results from one study to another. So, in 2013 CIRM created an iPSC Repository, a kind of high tech stem cell bank. The repository collected tissue samples from people who have different diseases, turned those samples into high quality stem cell lines – the kind known as induced pluripotent stem cells (iPSC) – and then made those samples available to researchers around the world. This not only gave researchers a powerful resource to use in developing a deeper understanding of different diseases, but because the scientists were all using the same cell lines that meant their findings could be compared to each other.

That same year we also launched a plan to create a new, statewide network of clinics that specialize in using stem cells to treat patients. The goal of the Alpha Stem Cell Clinics Network is to support and accelerate clinical trials for programs funded by the agency, academic researchers or industry. We felt that because stem cell therapies are a completely new way of treating diseases and disorders, we needed a completely new way of delivering treatments in a safe and effective manner.

The network began with three clinics – UC San Diego, UCLA/UC Irvine, and City of Hope – but at our last Board meeting was expanded to five with the addition of UC Davis and UCSF Benioff Children’s Hospital Oakland. This network will help the clinics streamline challenging processes such as enrolling patients, managing regulatory procedures and sharing data and will speed the testing and distribution of experimental stem cell therapies. We will be posting a more detailed blog about how our Alpha Clinics are pushing innovative stem cell treatments tomorrow.

As the field advanced we knew that we had to find a new way to help researchers move their research out of the lab and into clinical trials where they could be tested in people. Many researchers were really good at the science, but had little experience in navigating the complex procedures needed to get the green light from the US Food and Drug Administration (FDA) to test their work in a clinical trial.

So, our Agency created the Translating (TC) and Accelerating Centers (AC). The idea was that the TC would help researchers do all the preclinical testing necessary to apply for permission from the FDA to start a clinical trial. Then the AC would help the researchers set up the trial and actually run it.

In the end, one company, Quintiles IMS, won both awards so we combined the two entities into one, The Stem Cell Center, a kind of one-stop-shopping home to help researchers move the most promising treatments into people.

That’s not the whole story of course – I didn’t even mention the Genomics Initiative – but it’s hard to cram 13 years of history into a short blog. And we’re not done yet. We are always looking for new ways to improve what we do and how we do it. We are a work in progress, and we are determined to make as much progress as possible in the years to come.

CIRM-Funded Clinical Trials Targeting Cancers

Welcome to the Month of CIRM!

As we mentioned in last Thursday’s blog, during the month of October we’ll be looking back at what CIRM has done since the agency was created by the people of California back in 2004. To start things off, we’ll be focusing on CIRM-funded clinical trials this week. Supporting clinical trials through our funding and partnership is a critical cornerstone to achieving our mission: to accelerate stem cell treatments to patients with unmet medical needs.

Over the next four days, we will post infographics that summarize CIRM-funded trials focused on therapies for cancer, neurologic disorders, heart and metabolic disease, and blood disorders. Today, we review the nine CIRM-funded clinical trial projects that target cancer. The therapeutic strategies are as varied as the types of cancers the researchers are trying to eradicate. But the common element is developing cutting edge methods to outsmart the cancer cell’s ability to evade standard treatment.

For more details about all CIRM-funded clinical trials, visit our clinical trials page and read our clinical trials brochure which provides brief overviews of each trial.

Stem Cell Stories That Caught our Eye: Insights into a healthy brain, targeting mutant cancers and commercializing cell therapies

Here’s your weekly roundup of interesting stem cell stories!

Partnership for a healthy brain. To differentiate or not to differentiate. That is the question the stem cells in our tissues and organs face.

In the case of the brain, neural precursor cells can either remain in a stem cell state or they can differentiate into mature brain cells called neurons and astrocytes. Scientists are interested in understanding how the brain maintains the balance between these different cell states in order to understand how disruption to this balance are associated with psychiatric and neurodegenerative diseases.

Scientists from the Salk Institute, led by Genetics Professor Rusty Gage, published a study this week in Cell Stem Cell that sheds light on how this imbalance can cause brain disease. They found that a partnership between two proteins determines whether a neural precursor develops into a neuron or an astrocyte.

One of these proteins is called Nup153. It’s a protein that’s part of the nuclear pore complex, which sits on the surface of the nuclear membrane and controls the entry and exit of various proteins and molecules. In collaboration with another Salk team under the leadership of Martin Hetzer, Gage discovered that Nup153 was expressed at different levels depending on the cell type. Neural precursors had high levels of Nup153 protein, immature neurons had what they defined as an intermediate level while astrocytes had the lowest level.

When they blocked the function of Nup153, neural precursors differentiated, which led them to conclude that the levels of Nup153 can influence the fate of neural precursor cells. The teams also discovered that Nup153 interacts with the transcription factor Sox2 and that the levels of Sox2 in the different cell types was similar to the levels of Nup153.

A fluorescent microscopy image shows Nup153 (red) in pore complexes encircling and associating with Sox2 (green) in a precursor cell nucleus. Credit: Salk Institute/Waitt Center

In a Salk News release, first author on the study, Tomohisa Toda, explained how their findings shed light on basic cellular processes:

“The fact that we were able to connect transcription factors, which are mobile switches, to the pore complex, which is a very stable structure, offers a clue as to how cells maintain their identity through regulated gene expression.”

Gage’s team will next study how this partnership between the nuclear pore complex and transcription factors can influence the function of neurons in hopes of gaining more understanding of how an imbalance in these interactions can lead to neurological diseases.

“Increasingly, we are learning that diseases like schizophrenia, depression and Alzheimer’s all have a cellular basis. So we are eager to understand how specific brain cells develop, what keeps them healthy and why advancing age or other factors can lead to disease.”

Tomohisa Toda and Rusty Gage. Credit: Salk Institute

Targeting KRAS Mutant Cancer.

CIRM-funded scientists at UC San Diego School of Medicine have developed a new strategy to target cancers that are caused by a mutation in the KRAS gene. Their findings were published in the journal Cancer Discovery.

The KRAS protein is essential for normal signaling processes in tissues, but mutant versions of this protein can cause cancer. According to a UC San Diego Health news release about the study, “there are currently no effective treatments for the 95 percent of pancreatic cancers and up to 30 percent of non-small cell lung cancers with KRAS mutations.”

To address this need, the team identified a biomarker called αvb3 that is associated with cancers dependent on the KRAS mutation. They observed that a protein called Galectin-3 binds to αvb3, which is an integrin receptor on the surface of cancer cells, to promote mutant KRAS’s cancer-causing ability.

This realization offered the team a path towards potential treatments. By inhibiting Galectin-3 with a drug called GCS-100, the scientists would make KRAS-addicted cancers go cold turkey. Senior author on the study, David Cheresh, explained,

“This may be among the first approaches to successfully target KRAS mutant cancers. Previously, we didn’t understand why only certain KRAS-initiated cancers would remain addicted to the mutation. Now we understand that expression of integrin αvb3 creates the addiction to KRAS. And it’s those addicted cancers that we feel will be most susceptible to targeting this pathway using Galectin-3 inhibitors.”

Cheresh concluded that this novel approach could pave the way for a personalized medicine approach for KRAS-addicted cancers.

“KRAS mutations impact a large number of patients with cancer. If a patient has a KRAS mutant cancer, and the cancer is also positive for αvb3, then the patient could be a candidate for a therapeutic that targets this pathway. Our work suggests a personalized medicine approach to identify and exploit KRAS addicted tumors, providing a new opportunity to halt the progression of tumors that currently have no viable targeted therapeutic options.”

Commercializing cell therapy.

Our friends at RegMedNet made an infographic that illustrates how cell therapies have developed over time and how these therapies are advancing towards commercialization.

The infographic states, “The cell therapy industry is rapidly evolving, with new techniques, technology and applications being developed all the time. After some high-profile failures, all eyes are on regulating existing therapies to ensure patient safety is paramount. Legislators, regulators and other stakeholders around the world are navigating a difficult line between hope, hype and the scientific evidence.”

Check out their timeline below and visit the RegMedNet website for more news and information about the regenerative medicine field.

Taming the Zika virus to kill cancer stem cells that drive lethal brain tumor

An out of control flame can be very dangerous, even life-threatening. But when harnessed, that same flame sustains life in the form of warm air, a source of light, and a means to cook.

A similar duality holds true for viruses. Once it infects the body, a virus can replicate like wildfire and cause serious illness and sometimes death. But in the lab, researchers can manipulate viruses to provide an efficient, harmless method to deliver genetic material into cells, as well as to prime the immune system to protect against future infections.

In a Journal of Experimental Medicine study published this week, researchers from the University of Washington, St. Louis and UC San Diego also show evidence that a virus, in this case the Zika virus, could even be a possible therapy for a hard-to-treat brain cancer called glioblastoma.

Brain cancer stem cells (left) are killed by Zika virus infection (image at right shows cells after Zika treatment). Image: Zhe Zhu, Washington U., St. Louis.

Recent outbreaks of the Zika virus have caused microcephaly during fetal development. Babies born with microcephaly have a much smaller than average head size due to a lack of proper brain development. Children born with this condition suffer a wide range of devastating symptoms like seizures, difficulty learning, and movement problems just to name a few. In the race to understand the outbreak, scientists have learned that the Zika virus induces microcephaly by infecting and killing brain stem cells, called neural progenitors, that are critical for the growth of the developing fetal brain.

Now, glioblastoma tumors contain a small population of cells called glioblastoma stem cells (GSCs) that, like neural progenitors, can lay dormant but also make unlimited copies of themselves.  It’s these properties of glioblastoma stem cells that are thought to allow the glioblastoma tumor to evade treatment and grow back. The research team in this study wondered if the Zika virus, which causes so much damage to neural progenitors in developing babies, could be used for good by infecting and killing cancer stem cells in glioblastoma tumors in adult patients.

To test this idea, the scientists infected glioblastoma brain tumor samples with Zika and showed that the virus spreads through the cells but primarily kills off the glioblastoma stem cells, leaving other cells in the tumor unscathed. Since radiation and chemotherapy are effective at killing most of the tumor but not the cancer stem cells, a combination of Zika and standard cancer therapies could provide a knockout punch to this aggressive brain cancer.

Even though Zika virus is much more destructive to the developing fetal brain than to adult brains, it’s hard to imagine the US Food and Drug Administration ever approving the injection of a dangerous virus into the site of a glioblastoma tumor. So, the scientists genetically modified the Zika virus to make it more sensitive to the immune system’s first line of defense called the innate immunity. With just the right balance of genetic alterations, it might be possible to retain the Zika virus’ ability to kill off cancer stem cells without causing a serious infection.

The results were encouraging though not a closed and shut case: when glioblastoma cancer stem cells were infected with these modified Zika virus strains, the virus’ cancer-killing abilities were weaker than the original Zika strains but still intact. Based on these results, co-senior author and WashU professor, Dr. Michael S. Diamond, plans to make more tweaks to the virus to harness it’s potential to treat the cancer without infecting the entire brain in the process.

“We’re going to introduce additional mutations to sensitize the virus even more to the innate immune response and prevent the infection from spreading,” said Diamond in a press release. “Once we add a few more changes, I think it’s going to be impossible for the virus to overcome them and cause disease.”

 

Extra dose of patience needed for spinal cord injury stem cell therapies, rat study suggests

2017 has been an exciting year for Asterias Biotherapeutics’ clinical trial which is testing a stem cell-based therapy for spinal cord injury. We’ve written several stories about patients who have made remarkable recoveries after participating in the trial (here and here).

But that doesn’t mean researchers at other companies or institutes who are also investigating spinal cord injury will be closing up shop. There’s still a long way to go with the Asterias trial and there’s still a lot to be learned about the cellular and molecular mechanisms of spinal cord injury repair, which could lead to alternative options for victims. Continued studies will also provide insights on optimizing the methods and data collection used in future clinical trials.

Human neuronal stem cells extend axons (green) three months after transplantation in rat model of spinal cord injury. Image: UCSD

In fact, this week a team of UC San Diego scientists report in the Journal of Clinical Investigation that, based on brain stem cell transplant studies in a rat model of spinal cord injury, recovery continues long after the cell therapy is injected. These findings suggest that collecting clinical trial data too soon may give researchers the false impression that their therapy is not working as well as they had hoped.

In this study, funded in part by CIRM, the researchers examined brain stem cells – or neural stem cells, in lab lingo – that were derived from human embryonic stem cells. These neural stem cells (NSCs) aren’t fully matured and give rise to nerve cells as well as support cells called glia. Previous studies have shown that when NSCs are transplanted into rodent models of spinal cord injury, the cells mature into nerve cells, make connections with nerves within the animal and can help restore some limb movement.

But the timeline for the maturation of the NSCs after transplantation into the injury site wasn’t clear because most studies only measured recovery for a few weeks or months. To get a clearer picture, the UCSD team analyzed the fate and impact of human NSCs in adult rats with spinal cord injury from 1 month to 1.5 years – the longest time such an experiment has been carried out so far. The results confirmed that the transplanted NSCs did indeed survive through the 18-month time point and led to recovery of movement in the animals’ limbs.

To their surprise, the researchers found that the NSCs continued to mature and some cell types didn’t fully specialize until 6 months or even 12 months after the transplantation. This timeline suggests that although the human cells are placed into the hostile environment of an injury site in an animal model, they still follow a maturation process seen during human development.

The researchers also focused on the fate of the nerve cells’ axons, the long, thin projections that relay nerve signals and make connections with other nerve cells. Just as is seen with normal human development, these axons were very abundant early in the experiment but over several months they went through a pruning process that’s critical for healthy nerve function.

Altogether, these studies provide evidence that waiting for the clinical trial results of stem cell-based spinal cord injury therapies will require an extra dose of patience. Team lead, Dr. Mark Tuszynski, director of the UC San Diego Translational Neuroscience Institute, summed it up this way in a press release:

Mark Tuszynski, UCSD

“The bottom line is that clinical outcome measures for future trials need to be focused on long time points after grafting. Reliance on short time points for primary outcome measures may produce misleadingly negative interpretation of results. We need to take into account the prolonged developmental biology of neural stem cells. Success, it would seem, will take time.”

Confusing cancer to kill it

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Thomas Kipps, MD, PhD: Photo courtesy UC San Diego

Confusion is not a state of mind that we usually seek out. Being bewildered is bad enough when it happens naturally, so why would anyone actively pursue it? But now some researchers are doing just that, using confusion to not just block a deadly blood cancer, but to kill it.

Today the CIRM Board approved an investment of $18.29 million to Dr. Thomas Kipps and his team at UC San Diego to use a one-two combination approach that we hope will kill Chronic Lymphocytic Leukemia (CLL).

This approach combines two therapies, cirmtuzumab (a monoclonal antibody developed with CIRM funding, hence the name) and Ibrutinib, a drug that has already been approved by the US Food and Drug Administration (FDA) for patients with CLL.

As Dr. Maria Millan, our interim President and CEO, said in a news release, the need for a new treatment is great.

“Every year around 20,000 Americans are diagnosed with CLL. For those who have run out of treatment options, the only alternative is a bone marrow transplant. Since CLL afflicts individuals in their 70’s who often have additional medical problems, bone marrow transplantation carries a higher risk of life threatening complications. The combination approach of  cirmtuzumab and Ibrutinib seeks to offer a less invasive and more effective alternative for these patients.”

Ibrutinib blocks signaling pathways that leukemia cells need to survive. Disrupting these pathways confuses the leukemia cell, leading to its death. But even with this approach there are cancer stem cells that are able to evade Ibrutinib. These lie dormant during the therapy but come to life later, creating more leukemia cells and causing the cancer to spread and the patient to relapse. That’s where cirmtuzumab comes in. It works by blocking a protein on the surface of the cancer stem cells that the cancer needs to spread.

It’s hoped this one-two punch combination will kill all the cancer cells, increasing the number of patients who go into complete remission and improve their long-term cancer control.

In an interview with OncLive, a website focused on cancer professionals, Tom Kipps said Ibrutinib has another advantage for patients:

“The patients are responding well to treatment. It doesn’t seem like you have to worry about stopping therapy, because you’re not accumulating a lot of toxicity as you would with chemotherapy. If you administered chemotherapy on and on for months and months and years and years, chances are the patient wouldn’t tolerate that very well.”

The CIRM Board also approved $5 million for Angiocrine Bioscience Inc. to carry out a Phase 1 clinical trial testing a new way of using cord blood to help people battling deadly blood disorders.

The standard approach for this kind of problem is a bone marrow transplant from a matched donor, usually a family member. But many patients don’t have a potential donor and so they often have to rely on a cord blood transplant as an alternative, to help rebuild and repair their blood and immune systems. However, too often a single cord blood donation does not have enough cells to treat an adult patient.

Angiocrine has developed a product that could help get around that problem. AB-110 is made up of cord blood-derived hematopoietic stem cells (these give rise to all the other types of blood cell) and genetically engineered endothelial cells – the kind of cell that lines the insides of blood vessels.

This combination enables the researchers to take cord blood cells and greatly expand them in number. Expanding the number of cells could also expand the number of patients who could get these potentially life-saving cord blood transplants.

These two new projects now bring the number of clinical trials funded by CIRM to 35. You can read about the other 33 here.

 

 

 

CIRM weekly stem cell roundup: minibrain model of childhood disease; new immune insights; patient throws out 1st pitch

New human Mini-brain model of devastating childhood disease.
The eradication of Aicardi-Goutieres Syndrome (AGS) can’t come soon enough. This rare but terrible inherited disease causes the immune system to attack the brain. The condition leads to microcephaly (an abnormal small head and brain size), muscle spasms, vision problems and joint stiffness during infancy. Death or a persistent comatose state is common by early childhood. There is no cure.

Though animal models that mimic AGS symptoms are helpful, they don’t reflect the human disease closely enough to provide researchers with a deeper understanding of the mechanisms of the disease. But CIRM-funded research published this week may be a game changer for opening up new therapeutic strategies for the children and their families that are suffering from AGS.

Organoid mini-brains are clusters of cultured cells self-organized into miniature replicas of organs. Image courtesy of Cleber A. Trujillo, UC San Diego.

To get a clearer human picture of the disease, Dr. Alysson Muotri of UC San Diego and his team generated AGS patient-derived induced pluripotent stem cells (iPSCs). These iPSCs were then grown into “mini-brains” in a lab dish. As described in Cell Stem Cell, their examination of the mini-brains revealed an excess of chromosomal DNA in the cells. This abnormal build up causes various toxic effects on the nerve cells in the mini-brains which, according to Muotri, had the hallmarks of AGS in patients:

“These models seemed to mirror the development and progression of AGS in a developing fetus,” said Muotri in a press release. “It was cell death and reduction when neural development should be rising.”

In turns out that the excess DNA wasn’t just a bunch of random sequences but instead most came from so-called LINE1 (L1) retroelements. These repetitive DNA sequences can “jump” in and out of DNA chromosomes and are thought to be remnants of ancient viruses in the human genome. And it turns out the cell death in the mini-brains was caused by the immune system’s anti-viral response to these L1 retroelements. First author Charles Thomas explained why researchers may have missed this in their mouse models:

“We uncovered a novel and fundamental mechanism, where chronic response to L1 elements can negatively impact human neurodevelopment. This mechanism seems human-specific. We don’t see this in the mouse.”

The team went on to test the anti-retroviral effects of HIV drugs on their AGS models. Sure enough, the drugs decreased the amount of L1 DNA and cell growth rebounded in the mini-brains. The beauty of using already approved drugs is that the route to clinical trials is much faster and in fact a European trial is currently underway.

For more details, watch this video interview with Dr. Muotri:

New findings about immune cell development may open door to new cancer treatments
For those of you who suffer with seasonal allergies, you can blame your sniffling and sneezing on an overreaction by mast cells. These white blood cells help jump start the immune system by releasing histamines which makes blood vessels leaky allowing other immune cells to join the battle to fight disease or infection. Certain harmless allergens like pollen are mistaken as dangerous and can also cause histamine release which triggers tearing and sneezing.

Mast cells in lab dish. Image: Wikipedia.

Dysfunction of mast cells are also involved in some blood cancers. And up until now, it was thought a protein called stem cell factor played the key role in the development of blood stem cells into mast cells. But research reported this week by researchers at Karolinska Institute and Uppsala University found cracks in that previous hypothesis. Their findings published in Blood could open the door to new cancer therapies.

The researchers examine the effects of the anticancer drug Glivec – which blocks the function of stem cell factor – on mast cells in patients with a form of leukemia. Although the number of mature mast cells were reduced by the drug, the number of progenitor mast cells were not. The progenitors are akin to teenagers in that they’re at an intermediate stage of development, more specialized than stem cells but not quite mast cells. The team went on to confirm that stem cell factor was not required for the mast cell progenitors to survive, multiply and mature. Instead, their work identified two other growth factors, interleukin 3 and 6, as important for mast cell development.

In a press release, lead author Joakim Dahlin, explained how these new insights could lead to new therapies:

“The study increases our understanding of how mast cells are formed and could be important in the development of new therapies, for example for mastocytosis for which treatment with imatinib/Glivec is not effective. One hypothesis that we will now test is whether interleukin 3 can be a new target in the treatment of mast cell-driven diseases.”

Patient in CIRM-funded trial regains use of arms, hands and fingers will throw 1st pitch in MLB game.
We end this week with some heart-warming news from Asterias Biotherapeutics. You avid Stem Cellar readers will remember our story about Lucas Lindner several weeks back. Lucas was paralyzed from the neck down after a terrible car accident. Shortly after the accident, in June of 2016, he enrolled in Asterias’ CIRM-funded trial testing an embryonic stem cell-based therapy to treat his injury. And this Sunday, August 13th, we’re excited to report that due to regaining the use of his arms, hands and fingers since the treatment, he will throw out the first pitch of a Major League Baseball game in Milwaukee. Congrats to Lucas!

For more about Lucas’ story, watch this video produced by Asterias Biotherapeutics: