Blocking spike in stem cell growth after brain injury may lessen memory decline, seizures

Survivors of traumatic brain injury (TBI) often suffer from debilitating, life changing symptoms like memory decline and epileptic seizures. Researchers had observed that following TBI, a stem cell-rich area of the brain provides a spike in new nerve cell growth, presumably to help replace damaged or destroyed brain cells. But, like a lot of things in biology, more is not always better. And a new report in Stem Cell Reports provides evidence that this spark of brain cell growth shortly after TBI may actually be responsible for post-injury seizures as well as long-term memory problems for people with this condition.The Rutgers University research team behind the study came to this counterintuitive conclusion by examining brain injury in laboratory rats. They showed that brain cells at the injury site that are known to play a role in memory had doubled in number within three days after injury. But a month later, these brain cells had decreased by more than half the amount seen in rats without injury. Neural stem cells, which develop into the mature cells found in the brain, showed this same up and down pattern, suggesting they were responsible for the loss of the brain cells. Lead scientist, professor Viji Santhakumar, described how these changes in brain cell growth lead to brain injury symptoms:

“There is an initial increase in birth of new neurons after a brain injury but within weeks, there is a dramatic decrease in the normal rate at which neurons are born, depleting brain cells that under normal circumstances should be there to replace damaged cells and repair the brain’s network,” she said in a press release. “The excess new neurons lead to epileptic seizures and could contribute to cognitive decline. It is normal for the birth of new neurons to decline as we age. But what we found in our study was that after a head injury the decline seems to be more rapid.”

The researchers next aimed to slow down this increase in nerve cell growth after injury. To accomplish this goal, they used an anti-cancer drug currently in clinical trials which has been known to block the growth and survival of new nerve cells. Sure enough, the drug blocked this initial, rapid burst in nerve cells in the rats, which prevented the long-term decline in the brain cells that are involved in memory decline. The team also reported that the rats were less vulnerable to seizures when this drug was administered.

“That’s why we believe that limiting this process might be beneficial to stopping seizures after brain injury,” Dr. Santhakumar commented.

Hopefully, these findings will one day help lessen these short- and long-term, life-altering symptoms seen after brain injury.

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Attractive new regenerative medicine tool uses magnets to shape and stimulate stem cells

The ultimate goal of tissue engineers who work in the regenerative medicine field is to replace damaged or diseased organs with new ones built from stem cells. To accomplish the feat, these researchers are developing new tools and techniques to manipulate and specialize stem cells into three dimensional structures. Some popular methods – which we’ve blogged about often – include the use of bioscaffolds as well as 3D bioprinting . This week, a research team at the Laboratoire Matière et Systèmes Complexes in France has developed an attractive (pun intended!) new tool that uses magnetized stem cells to both manipulate and stimulate the cells into 3D shapes.

The magnetic stretcher: this all-in-one system can both form and mechanically stimulate an aggregate of magnetized embryonic stem cells. Image: © Claire Wilhelm / Laboratoire Matière et systèmes complexes (CNRS/Université Paris Diderot).

The study, reported on Monday in Nature Communications, used embryonic stem cells which were incubated with magnetic nanoparticles. The cells readily take up the nanoparticles which allowed the scientists to group the individual cells using magnets. But first the team needed to show that the nanoparticles had no negative effects on the cells. Comparing the iron nanoparticle-laden stem cells to iron-free cells showed no difference in the cells’ survival and their ability to divide.

It was also important to make sure the introduction of nanoparticles had no impact on the stem cell’s pluripotency; that is, its ability to maintain its unspecialized state. A visual check of the cells through a microscope showed that they grew together in rounded clumps, a hallmark of undifferentiated, pluripotent cells. In addition, the key genes that bestow pluripotency onto embryonic stem cells were still active after the addition of the nanoparticles.

The stem cells’ ability to mature into various cell types, like heart muscle or nerve, is key to any successful tissue engineering project. So, the next important assessment of these magnetized cells was to make sure their ability to differentiate, or specialize, was still intact. The typical first step to differentiating embryonic stem cells is to form so-called embryoid bodies (EBs), which are 3D groups of pluripotent stem cells which begin differentiating into the three fundamental tissues types: mesoderm (gives rise to muscle, bone, fat), ectoderm (gives rise to nerve, hair, eyes), endoderm (gives rise to intestines, liver). Using a popular technique, called the hanging drop method, the team showed that the presence of the nanoparticles did not negatively affect embryoid body formation.

In fact, the use of magnets to form embryoid bodies provided several advantages over the hanging drop method. The hanging drop technique requires multiple, time-consuming steps and the resulting embryoid bodies tend to be inconsistent in size and shape. Use of the magnets, on the other hand, instantaneously assembled the stem cells into consistently round aggregates. And by precisely adjusting the magnetic force used, the scientists could also vary the size of the embyroid body, which is an important variable to control since the embryoid size can impact its ability to differentiate.

While the magnet used to form the embryoid bodies was kept stable, the researchers included another magnet which they could move. With this setup, the team was able to stretch and shape the group of cells without the need of scaffolds or the need to physically contact the cells. Several previous studies, using flat, 2-dimensional petri dishes, have shown that the stiffness and flexibility of the dish can stimulate gene activity by affecting cell shape. In this study, the researchers found that when the magnet was moved in a cyclical pattern that imitates the rhythm of a heart beat, the embryoid bodies were, if you can believe it, nudged toward a heart muscle fate. A press release by France’s National Center of Scientific Research (CNRS), which funded the study, explained the big picture implications of this new technique:

“This “all-in-one” approach, which makes it possible to build and manipulate tissue within the same system, could thus prove to be a powerful tool both for biophysical studies and tissue engineering.”

Protein that turns normal cells into cancer stem cells offers target to fight colon cancer

colon-cancer

Colon cancer: Photo courtesy WebMD

Colon cancer is a global killer. Each year more than one million people worldwide are diagnosed with it; more than half a million die from it. If diagnosed early enough the standard treatment involves surgery, chemotherapy, radiation or targeted drug therapy to destroy the tumors. In many cases this may work. But in some cases, while this approach helps put people in remission, eventually the cancer returns, spreads throughout the body, and ultimately proves fatal.

Now researchers may have identified a protein that causes normal cells to become cancerous, and turn into cancer stem cells (CSCs). This discovery could help provide a new target for anti-cancer therapies.

Cancer stem cells are devilishly tricky. While most cancer cells are killed by chemotherapy or other therapies, cancer stem cells are able to lie dormant and hide, then emerge later to grow and spread, causing the person to relapse and the cancer to return.

In a study published in Nature Research’s Scientific Reports, researchers at SU Health New Orleans School of Medicine and Stanley S. Scott Cancer Center identified a protein, called SATB2, that appears to act as an “on/off” switch for specific genes inside a cancer cell.

In normal, healthy colorectal tissue SATB2 is not active, but in colorectal cancer it is highly active, found in around 85 percent of tumors. So, working with mice, the researchers inserted extra copies of the SATB2 gene, which produced more SATB2 protein in normal colorectal tissue. They found that this produced profound changes in the cell, leading to uncontrolled cell growth. In effect it turned a normal cell into a cancer stem cell.

As the researchers state in their paper:

“These data suggest that SATB2 can transform normal colon epithelial cells to CSCs/progenitor-like cells which play significant roles in cancer initiation, promotion and metastasis.”

When the researchers took colorectal cancer cells and inhibited SATB2 they found that this not only suppressed the growth of the cancer and it’s ability to spread, it also prevented those cancer cells from becoming cancer stem cells.

In a news release about the study Dr. Rakesh Srivastava,  the senior author on the paper, said the findings are important:

“Since the SATB2 protein is highly expressed in the colorectal cell lines and tissues, it can be an attractive target for therapy, diagnosis and prognosis.”

Because SATB2 is found in other cancers too, such as breast cancer, these findings may hold significance for more than just colorectal cancer.

The next step is to repeat the study in mice that have been genetically modified to better reflect the way colon cancer shows up in people. The team hope this will not only confirm their findings, but also give them a deeper understanding of the role that SATB2 plays in cancer formation and spread.

CIRM-funded scientists discover a new way to make stem cells using antibodies

Just as learning a new skill takes time to hone, scientific discoveries take time to perfect. Such is the case with induced pluripotent stem cells (iPSCs), the Nobel Prize winning technology that reprograms mature adult cells back into a pluripotent stem cell state. iPSCs are a powerful tool because they can develop into any cell found in the body. Scientists use iPSCs to model diseases in a dish, screen for new drugs, and to develop stem cell-based therapies for patients.

iPSCs grown in a cell culture dish.

The original iPSC technology, discovered by Dr. Shinya Yamanaka in 2006, requires viral delivery of four transcription factor genes, Oct4, Sox2, Klf4, and c-Myc, into the nucleus of an adult cell. These genes are inserted into the genome where they are activated to churn out their respective proteins. The combined expression of these four factors (OSKM) turns off the genetic programming of an adult cell and turns on the programming for a pluripotent stem cell.

The technology is pretty neat and allows scientists to make iPSCs from patients using a variety of different tissue sources including skin, blood, and even urine. However, there is a catch. Inserting reprogramming genes into a cell’s genome can be disruptive if the reprogramming genes fail to switch off or can cause cancer if nefarious oncogenes are turned on.

In response to this concern, scientists are developing alternative methods for making iPSCs using non-invasive methods. A CIRM-funded team from The Scripps Research Institute (TSRI) published such a study yesterday in the journal Nature Biotechnology.

Led by senior author and CIRM grantee Dr. Kristin Baldwin, the TSRI team screened a large library of antibodies – proteins that recognize and bind to specific molecules – to identify ones that could substitute for the OSKM reprogramming factors. The hope was that some of these antibodies would bind to proteins on the surface of cells and turn on a molecular signaling cascade from the outside that would turn on the appropriate reprogramming genes from the inside of the cell.

The scientists screened over 100 million antibodies and found ones that could replace three of the four reprogramming factors (Oct4, Sox2, and c-Myc) when reprogramming mouse skin cells into iPSCs. They were unable to find an antibody to replace Klf4 in the current study but have it on their to-do list for future studies.

Dr. Baldwin explained how her team’s findings improve upon previous reprogramming methods in a TSRI news release,

Kristen Baldwin

“This result suggests that ultimately we might be able to make IPSCs without putting anything in the cell nucleus, which potentially means that these stem cells will have fewer mutations and overall better properties.”

 

Other groups have published other non-invasive iPSC reprogramming methods using cocktails of chemicals, proteins or microRNAs in place of virally delivering genes to make iPSCs. However, Baldwin’s study is the first (to our knowledge) to use antibodies to achieve this feat.

An added benefit to antibody reprogramming is that the team was able to learn more about the signaling pathways that were naturally activated by the iPSC reprogramming antibodies.

“The scientists found that one of the Sox2-replacing antibodies binds to a protein on the cell membrane called Basp1. This binding event blocks Basp1’s normal activity and thus removes the restraints on WT1, a transcription factor protein that works in the cell nucleus. WT1, unleashed, then alters the activity of multiple genes, ultimately including Sox2’s, to promote the stem cell state using a different order of events than when using the original reprogramming factors.”

iPSCs made by antibody reprogramming could address some of the long-standing issues associated with more traditional reprogramming methods and could offer further insights into the complex signaling required to turn adult cells back into a pluripotent state. Baldwin and her team are now on the hunt for antibodies that will reprogram human (rather than mouse) cells into iPSCs. Stay tuned!

UCLA launches CIRM-funded clinical trial using engineered blood stem cells to treat skin cancer

It’s not uncommon for biomedical institutes as well as their funding partners to announce through press releases that a clinical trial they’re running has gotten off the ground and has started to enroll patients. For an outsider looking in, it may seem like they’re jumping the gun a bit. No patients have received the therapy. No cures have been declared. So why all the hubbub at the start?

The reality is this: the launch of a clinical trial isn’t a beginning. It represents many years of effort by many researchers and a lot of funding to take an idea and develop it into a tangible product that has been given clearance to be tested in people to potentially save their lives. That’s why this important milestone deserves to be recognized. So, we were excited to get the word out, in the form of a press release , that UCLA had announced this morning the launch of a CIRM-funded clinical trial testing a therapy for hard-to-treat cancers.

The UCLA clinical trial genetically alters a patient’s hematopoietic stem cells give rise to T cells that are efficient cancer killers.

It’s estimated that metastasis, or the spread of cancer to other parts of the body, is responsible for 90% of cancer deaths. Though radiation and chemotherapy treatments can stop a tumor in its tracks, a small population of cancer stem cells in the tumor lie dormant and can evade those anti-cancer approaches. Because of their unlimited potential to divide, the cancer stem cells regrow the tumor leading to its inevitable return and spread. Oncologists clearly need new approaches to help patients with this unmet medical need.

That’s where today’s clinical trial launch comes into the picture. Dr. Antonio Ribas, a member of the UCLA Broad Stem Cell Research Center, and his team have genetically engineered cancer-killing white blood cells called T cells and blood-forming stem cells collected from patients to produce a protein that, like a key in a lock, recognizes a protein found almost exclusively on the surface of many types of cancer. When the T cells are transfused back into the patient, they can more efficiently track down and eradicate hard-to-treat skin cancer stem cells. At the same, the transfused blood stem cells – which specialize into all the various immune system cells – provide a long-term supply of T cells for continued protection against reoccurrence of the tumor.

“Few options exist for the treatment of patients whose cancers have metastasized due to resistance to current therapies,” Ribas said in the UCLA press release. “This clinical trial will allow us to try a new approach that engineers the body’s immune system to fight metastasized tumors similar to how it fights germs and viruses.”

 

And as Dr. Maria Millan, CIRM’s President & CEO (interim), described in our accompanying press release, CIRM will be an ever-present partner to help Ribas’ team get the clinical trial smoothly out of the starting gate and provide the support needed to carry the therapy to its completion:

“This trial is the first step in developing a therapy that could alleviate the complications resulting from cancer metastases as well as potentially improving outcomes in cancer patients where there are currently no effective treatment options. We are confident that CIRM’s funding and partnership, in combination with the expertise provided by our Alpha Stem Cell Clinic network, will give provide critical support for the successful conduct of this important clinical trial.”

 

To learn more about this clinical trial, visit its page at clinicaltrials.gov. If you think you might be eligible to enroll, please contact Clinical Research Coordinator Justin Tran by email at justintran@mednet.ucla.edu or by phone at 310-206-2090.

Stem Cell Stories That Caught our Eye: Duchenne muscular dystrophy and short telomeres, motor neurons from skin, and students today, stem cell scientists tomorrow

Short telomeres associated with Duchenne Muscular Dystrophy.

Duchenne Muscular Dystrophy (DMD) is a severe muscle wasting disease that typically affects young men. There is no cure for DMD and the average life expectancy is 26. These are troubling facts that scientists at the University of Pennsylvania are hoping to change with their recent findings in Stem Cell Reports.

Muscle stem cells with telomeres shown in red. (Credit: Penn Medicine)

The team discovered that the muscle stem cells in DMD patients have shortened telomeres, which are the protective caps on the ends of chromosomes that prevent the loss of precious genetic information during cell division. Each time a cell divides, a small section of telomere is lost. This typically isn’t a problem because telomeres are long enough to protect cells through many divisions.

But it turns out this is not the case for the telomeres in the muscle stem cells of DMD patients. Because DMD patients have weak muscles, they experience constant muscle damage and their muscle stem cells have to divide more frequently (basically non-stop) to repair and replace muscle tissue. This is bad news for the telomeres in their muscle stem cells. Foteini Mourkioti, senior author on the study, explained in a news release,

“We found that in boys with DMD, the telomeres are so short that the muscle stem cells are probably exhausted. Due to the DMD, their muscle stem cells are constantly repairing themselves, which means the telomeres are getting shorter at an accelerated rate, much earlier in life. Future therapies that prevent telomere loss and keep muscle stem cells viable might be able to slow the progress of disease and boost muscle regeneration in the patients.”

With these new insights, Mourkioti and his team believe that targeting muscle stem cells before their telomeres become too short is a good path to pursue for developing new treatments for DMD.

“We are now looking for signaling pathways that affect telomere length in muscle stem cells, so that in principle we can develop drugs to block those pathways and maintain telomere length.”

Making Motor Neurons from Skin.

Skin cells and brain cells are like apples and oranges, they look completely different and have different functions. However, in the past decade, researchers have developed methods to transform skin cells into neurons to study neurodegenerative disorders and develop new strategies to treat brain diseases.

Scientists at Washington University School of Medicine in St. Louis published new findings on this topic yesterday in the journal Cell Stem Cell. In a nut shell, the team discovered that a specific combination of microRNAs (molecules involved in regulating what genes are turned on and off) and transcription factors (proteins that also regulate gene expression) can turn human skin cells into motor neurons, which are the brain cells that degenerate in neurodegenerative diseases like ALS, also known as Lou Gehrig’s disease.

Human motor neurons made from skin. (Credit: Daniel Abernathy)

This magical cocktail of factors told the skin cells to turn off genes that make them skin and turn on genes that transformed them into motor neurons. The scientists used skin cells from healthy individuals but will soon use their method to make motor neurons from patients with ALS and other motor neuron diseases. They are also interested in generating neurons from older patients who are more advanced in their disease. Andrew Yoo, senior author on the study, explained in a news release,

“In this study, we only used skin cells from healthy adults ranging in age from early 20s to late 60s. Our research revealed how small RNA molecules can work with other cell signals called transcription factors to generate specific types of neurons, in this case motor neurons. In the future, we would like to study skin cells from patients with disorders of motor neurons. Our conversion process should model late-onset aspects of the disease using neurons derived from patients with the condition.”

This research will make it easier for other scientists to grow human motor neurons in the lab to model brain diseases and potentially develop new treatments. However, this is still early stage research and more work should be done to determine whether these transformed motor neurons are the “real deal”. A similar conclusion was shared by Julia Evangelou Strait, the author of the Washington University School of Medicine news release,

“The converted motor neurons compared favorably to normal mouse motor neurons, in terms of the genes that are turned on and off and how they function. But the scientists can’t be certain these cells are perfect matches for native human motor neurons since it’s difficult to obtain samples of cultured motor neurons from adult individuals. Future work studying neuron samples donated from patients after death is required to determine how precisely these cells mimic native human motor neurons.”

Students Today, Scientists Tomorrow.

What did you want to be when you were growing up? For Benjamin Nittayo, a senior at Cal State University Los Angeles, it was being a scientist researching a cure for acute myeloid leukemia (AML), a form of blood cancer that took his father’s life. Nittayo is making his dream into a reality by participating in a summer research internship through the Eugene and Ruth Roberts Summer Student Academy at the City of Hope in Duarte California.

Nittayo has spent the past two summers doing cancer research with scientists at the Beckman Research Institute at City of Hope and hopes to get a PhD in immunology to pursue his dream of curing AML. He explained in a City of Hope news release,

“I want to carry his memory on through my work. Being in this summer student program helped me do that. It influenced the kind of research I want to get into as a scientist and it connected me to my dad. I want to continue the research I was able to start here so other people won’t have to go through what I went through. I don’t wish that on anybody.”

The Roberts Academy also hosts high school students who are interested in getting their first experience working in a lab. Some of these students are part of CIRM’s high school educational program Summer Program to Accelerate Regenerative Medicine Knowledge or SPARK. The goal of SPARK is to train the next generation of stem cell scientists in California by giving them hands-on training in stem cell research at leading institutes in the state.

This year, the City of Hope hosted the Annual SPARK meeting where students from the seven different SPARK programs presented their summer research and learned about advances in stem cell therapies from City of Hope scientists.

Ashley Anderson, a student at Mira Costa High School in Manhattan Beach, had the honor of giving the City of Hope SPARK student talk. She shared her work on Canavan’s disease, a progressive genetic disorder that damages the brain’s nerve cells during infancy and can cause problems with movement and muscle weakness.

Under the guidance of her mentor Yanhong Shi, Ph.D., who is a Professor of Developmental and Stem Cell Biology at City of Hope, Ashley used induced pluripotent stem cells (iPSCs) from patients with Canavan’s to generate different types of brain cells affected by the disease. Ashley helped develop a protocol to make large quantities of neural progenitor cells from these iPSCs which the lab hopes to eventually use in clinical trials to treat Canavan patients.

Ashley has always been intrigued by science, but thanks to SPARK and the Roberts Academy, she was finally able to gain actual experience doing science.

“I was looking for an internship in biosciences where I could apply my interest in science more hands-on. Science is more than reading a textbook, you need to practice it. That’s what SPARK has done for me. Being at City of Hope and being a part of SPARK was amazing. I learned so much from Dr. Shi. It’s great to physically be in a lab and make things happen.”

You can read more about Ashley’s research and those of other City of Hope SPARK students here. You can also find out more about the educational programs we fund on our website and on our blog (here and here).

Hearts and brains are center stage at CIRM Patient Advocate event

Describing the work of a government agency is not the most exciting of topics. Books on the subject would probably be found in the “Self-help for Insomniacs” section of a good bookstore (there are still some around). But at CIRM we are fortunate. When we talk about what we do, we don’t talk about the mechanics of our work, we talk about our mission: accelerating stem cell therapies to people with unmet medical needs.

Yesterday at the Gladstone Institutes in San Francisco we did just that, talking about the progress being made in stem cell research to an audience of friends, supporters and patient advocates. We had a lot to talk about, including the 35 clinical trials we have funded so far, and our goals and hopes for the future.

We were lucky to have Dr. Deepak Srivastava and Dr. Steve Finkbeiner from Gladstone join us to talk about their work. Some people are good scientists, some are good communicators. Deepak and Steve are great scientists and equally great communicators.

Deepak Srivastava highlighted ongoing stem cell research at the Gladstone
(Photo: Todd Dubnicoff/CIRM)

Deepak is the Director of the Roddenberry Stem Cell Center at Gladstone (and yes, it’s named after Gene Roddenberry of Star Trek fame) and an expert on heart disease. He talked about how advances in research have enabled us to turn heart scar tissue cells into new heart muscle cells, creating the potential to use a person’s own cells to help them recover from a heart attack.

“If you have a heart attack, your heart turns that muscle into scar tissue which affects the heart’s ability to pump blood around the body. We identified a combination of factors that support cells that are already in your heart and we have found a way of converting those scar cells into muscle. This could help repair the heart enough so you may not need a transplant, but you can lead a much more normal life.”

He said this research is now advancing to the point where they hope it could be ready for testing in people in the not too distant future and joked that his father, who has had a heart attack, volunteered to be the second person to try it. “Not the first but definitely the second.”

Steve, who is the Director of the Taube/Koret Center for Neurodegenerative Disease Research, specializes in problems in the brain; everything from Alzheimer’s and Parkinson’s to schizophrenia and ALS (also known as Lou Gehrig’s disease.

He talked about his uncle, who has end stage Parkinson’s disease, and how he sees first-hand how devastating this neurodegenerative disease is, and how that personal connection helps motivate him to work ever harder.

He talked about how so many therapies that look promising in mice fail when they are tested in people:

“A huge motivation for me has been to try and figure out a more reliable way to test these potential therapies and to move discoveries from the lab and into clinical trials in patients.”

Steve is using ordinary skin cells or tissue samples, taken from people with Parkinson’s and Alzheimer’s and other neurological conditions, and using the iPSC technique developed by Shinya Yamanaka (who is a researcher at Gladstone and also Director of CIRA in Japan) turns them into the kinds of cells found in the brain. These cells then enable him to study how these different diseases affect the brain, and come up with ways that might stop their progress.

Steve Finkbeiner is using human stem cells to model brain diseases
(Photo: Todd Dubnicoff/CIRM)

He uses a robotic microscope – developed at Gladstone – that allows his team to study these cells and test different potential therapies 24 hours a day, seven days a week. This round-the-clock approach will hopefully help speed up his ability to find something that help patients.

The CIRM speakers – Dr. Maria Millan, our interim President and CEO – and Sen. Art Torres (ret.) the Vice Chair of our Board and a patient advocate for colorectal cancer – talked about the progress we are making in helping push stem cell research forward.

Dr. Millan focused on our clinical trial work and how our goal is to create a pipeline of promising projects from the work being done by researchers like Deepak and Steve, and move those out of the lab and into clinical trials in people as quickly as possible.

Sen. Art Torres (Ret.)
(Photo: Todd Dubnicoff/CIRM)

Sen. Torres focused on the role of the patient advocate at CIRM and how they help shape and influence everything we do, from the Board’s deciding what projects to support and fund, to our creating Clinical Advisory Panels which involve a patient advocate helping guide clinical trial teams.

The event is one of a series that we hold around the state every year, reporting back to our friends and supporters on the progress being made. We feel, as a state agency, that we owe it to the people of California to let them know how their money is being spent.

We are holding two more of these events in the near future, one at UC Davis in Sacramento on October 10th, and one at Cedars-Sinai Medical Center in Los Angeles on October 30th.

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.”

 

Stories that caught our eye last week: dying cells trigger stem cells, CRISPR videogames and an obesity-stem cell link

A dying cell’s last breath triggers stem cell division. Most cells in your body are in a constant state of turnover. The cells of your lungs, for instance, replace themselves every 2 to 3 weeks and, believe it or not, you get a new intestine every 2 to 3 days. We can thank adult stem cells residing in these organs for producing the new replacement cells. But with this continual flux, how do the stem cells manage to generate just the right number of cells to maintain the same organ size? Just a slight imbalance would lead to either too few cells or too many which can lead to organ dysfunction and disease.

The intestine turnovers every five days. Stem cells (green) in the fruit fly intestine maintain organ size and structure. Image: Lucy Erin O’Brien/Stanford U.

Stanford University researchers published results on Friday in Nature that make inroads into explaining this fascinating, fundamental question about stem cell and developmental biology. Studying the cell turnover process of the intestine in fruit flies, the scientists discovered that, as if speaking its final words, a dying intestinal cell, or enterocyte, directly communicates with an intestinal stem cell to trigger it to divide and provide young, healthy enterocytes.

To reach this conclusion, the team first analyzed young enterocytes and showed that a protein these cells produce, called E-cadherin, blocks the release of a growth factor called EGF, a known stimulator of cell division. When young enterocytes became old and begin a process called programmed cell death, or apoptosis, the E-cadherin levels drop which removes the inhibition of EGF. As a result, a nearby stem cell now receives the EGF’s cell division signal, triggering it to divide and replace the dying cell. In her summary of this research in Stanford’s Scope blog, science writer Krista Conger explains how the dying cell’s signal to a stem cell ensures that there no net gain or loss of intestinal cells:

“The signal emitted by the dying cell travels only a short distance to activate only nearby stem cells. This prevents an across-the-board response by multiple stem cells that could result in an unwanted increase in the number of newly generated replacement cells.”

Because E-cadherin and the EGF receptor (EGFR) are each associated with certain cancers, senior author Lucy Erin O’Brien ponders the idea that her lab’s new findings may explain an underlying mechanism of tumor growth:

Lucy Erin O’Brien Image: Stanford U.

“Intriguingly, E-cadherin and EGFR are each individually implicated in particular cancers. Could they actually be cooperating to promote tumor development through some dysfunctional version of the normal renewal mechanism that we’ve uncovered?”

 

How a videogame could make gene editing safer (Kevin McCormack). The gene editing tool CRISPR has been getting a lot of attention this past year, and for good reason, it has the potential to eliminate genetic mutations that are responsible for some deadly diseases. But there are still many questions about the safety of CRISPR, such as how to control where it edits the genome and ensure it doesn’t cause unexpected problems.

Now a team at Stanford University is hoping to use a videogame to find answers to some of those questions. Here’s a video about their project:

The team is using the online game Eterna – which describes itself as “Empowering citizen scientists to invent medicine”. In the game, “players” can build RNA molecules that can then be used to turn on or off specific genes associated with specific diseases.

The Stanford team want “players” to design an RNA molecule that can be used as an On/Off switch for CRISPR. This would enable scientists to turn CRISPR on when they want it, but off when it is not needed.

In an article on the Stanford News website, team leader Howard Chang said this is a way to engage the wider scientific community in coming up with a solution:

Howard Chang
Photo: Stanford U.

“Great ideas can come from anywhere, so this is also an experiment in the democratization of science. A lot of people have hidden talents that they don’t even know about. This could be their calling. Maybe there’s somebody out there who is a security guard and a fantastic RNA biochemist, and they don’t even know it. The Eterna game is a powerful way to engage lots and lots of people. They’re not just passive users of information but actually involved in the process.”

They hope up to 100,000 people will play the game and help find a solution.

Altered stem cell gene activity partly to blame for obesity. People who are obese are often ridiculed for their weight problems because their condition is chalked up to a lack of discipline or self-control. But there are underlying biological processes that play a key role in controlling body weight which are independent of someone’s personality. It’s known that so-called satiety hormones – which are responsible for giving us the sensation that we’re full from a meal – are reduced in obese individuals compared to those with a normal weight.

Stem cells may have helped Al Roker’s dramatic weight loss after bariatric surgery. Photo: alroker.com

Bariatric surgery, which reduces the size of the stomach, is a popular treatment option for obesity and can lead to remarkable weight loss. Al Roker, the weatherman for NBC’s Today Show is one example that comes to mind of a weight loss success story after having this procedure. It turns out that the weight loss is not just due to having a smaller stomach and in turn smaller meals, but researchers have shown that the surgery also restores the levels of satiety hormones. So post-surgery, those individuals get a more normal, “I’m full”, feedback from their brains after eating a meal.

A team of Swiss doctors wanted to understand why the satiety hormone levels return to normal after bariatric surgery and this week they reported their answer in Scientific Reports. They analyzed enteroendocrine cells – the cells that release satiety hormones into the bloodstream and to the brain in response to food that enters the stomach and intestines – in obese individuals before and after bariatric surgery as well as a group of people with normal weight. The results showed that obese individuals have fewer enteroendocrine cells compared with the normal weight group. Post-surgery, those cells return to normal levels.

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Cells which can release satiety hormones are marked in green. For obese patients (middle), the number of these cells is markedly lower than for lean people (top) and for overweight patients three months after surgery (bottom). Image: University of Basil.

A deeper examination of the cells from the obese study group revealed altered patterns of gene activity in stem cells that are responsible for generating the enteroendocrine cells. In the post-surgery group, the patterns of gene activity, as seen in the normal weight group, are re-established. As mentioned in a University of Basil press release, these results stress that obesity is more than just a problem of diet and life-style choices:

“There is no doubt that metabolic factors are playing an important part. The study shows that there are structural differences between lean and obese people, which can explain lack of satiation in the obese.”

 

Stem cell therapy for Parkinson’s disease shows promise in monkeys

Tremors, muscle stiffness, shuffling, slow movement, loss of balance. These are all symptoms of Parkinson’s disease (PD), a neurodegenerative disorder that progressively destroys the dopamine-producing neurons in the brain that control movement.

While there is no cure for Parkinson’s disease, there are drugs like Levodopa and procedures like deep brain stimulation that alleviate or improve some Parkinsonian symptoms. What they don’t do, however, is slow or reverse disease progression.

Scientists are still trying to figure out what causes Parkinson’s patients to lose dopaminergic neurons, and when they do, they hope to stop the disease in its early stages before it can cause the debilitating symptoms mentioned above. In the meantime, some researchers see hope for treating Parkinson’s in the form of stem cell therapies that can replace the brain cells that are damaged or lost due to the disease.

Dopaminergic neurons derived from induced pluripotent stem cells. (Xianmin Zeng, Buck Institute)

Promising results in monkeys

This week, a team of Japanese scientists reported in the journal Nature that they treated monkeys with Parkinson’s-like symptoms by transplanting dopaminergic neurons made from human stem cells into their brains. To prevent the monkeys from rejecting the human cells, they were treated with immunosuppressive drugs. These transplanted neurons survived for more than two years without causing negative side effects, like tumor growth, and also improved PD symptoms, making it easier for the monkeys to move around.

The neurons were made from induced pluripotent stem cells (iPSCs), which are stem cells that can become any cell type in the body and are made by transforming mature human cells, like skin, back to an embryonic-like state. The scientists transplanted neurons made from the iPSCs of healthy people and PD patients into the monkeys and saw that both types of neurons survived and functioned properly by producing dopamine in the monkey brains.

Experts in the field spoke to the importance of these findings in an interview with Nature News. Anders Bjorklund, a neuroscientist at Lund University in Sweden, said “it’s addressing a set of critical issues that need to be investigated before one can, with confidence, move to using the cells in humans,” while Lorenz Studer, a stem-cell scientist at the Memorial Sloan Kettering Cancer Center in New York City, said that “there are still issues to work out, such as the number of cells needed in each transplant procedure. But the latest study is ‘a sign that we are ready to move forward.’”

Next stop, human trials

Jun Takahashi

Looking ahead, Jun Takahashi, the senior author on the study, explained that his team hopes to launch a clinical trial testing this iPSC-based therapy by the end of 2018. Instead of developing personalized iPSC therapies for individual PD patients, which can be time consuming and costly, Takahashi plans to make special donor iPSC lines (called human leukocyte antigen or HLA-homozygous iPSCs) that are immunologically compatible with a larger population of patients.

In a separate study published at the same time in Nature Communications, Takahashi and colleagues showed that transplanting neurons derived from immune-matched monkey iPSCs improved their survival and dampened the immune response.

The Nature News article does a great job highlighting the findings and significance of both studies and also mentions other research projects using stem cells to treat PD in clinical trials.

“Earlier this year, Chinese researchers began a Parkinson’s trial that used a different approach: giving patients neural-precursor cells made from embryonic stem cells, which are intended to develop into mature dopamine-producing neurons. A year earlier, in a separate trial, patients in Australia received similar cells. But some researchers have expressed concerns that the immature transplanted cells could develop tumour-causing mutations.

Meanwhile, researchers who are part of a Parkinson’s stem-cell therapy consortium called GForce-PD, of which Takahashi’s team is a member, are set to bring still other approaches to the clinic. Teams in the United States, Sweden and the United Kingdom are all planning trials to transplant dopamine-producing neurons made from embryonic stem cells into humans. Previously established lines of embryonic stem cells have the benefit that they are well studied and can be grown in large quantities, and so all trial participants can receive a standardized treatment.”

You can read more coverage on these research studies in STATnews, The San Diego Union Tribune, and Scientific American.

For a list of projects CIRM is funding on Parkinson’s disease, visit our website.