Stem Cell Stories that Caught Our Eye: GPS for Skin & Different Therapies for Aging vs. Injured Muscles?

Skin stem cells specialize into new skin by sensing neighborhood crowding
When embarking on a road trip, the GPS technology inside our smartphones helps us know where we are and how to get where we’re going. The stem cells buried in the deepest layers of our skin don’t have a GPS and yet, they do just fine determining their location, finding their correct destination and becoming the appropriate type of skin cell. And as a single organ, all the skin covering your body maintains the right density and just the right balance of skin stem cells versus mature skin cells as we grow from a newborn into adult.

crowdinginth

Skin cells growing in a petri dish (green: cytoskeleton, red: cell-cell junction protein).
Credit: MPI for Biology of Aging

This easily overlooked but amazing feat is accomplished as skin cells are continually born and die about every 30 days over your lifetime. How does this happen? It’s an important question to answer considering the skin is our first line of defense against germs, toxins and other harmful substances.

This week, researchers at the Max Planck Institute for Biology of Aging in Cologne, Germany reported a new insight into this poorly understood topic. The team showed that it all comes down to the skin cells sensing the level of crowding in their local environment. As skin stem cells divide, it puts the squeeze on neighboring stem cells. This physical change in tension on these cells “next door” triggers signals that cause them to move upward toward the skin surface and to begin maturing into skin cells.

Lead author Yekaterina Miroshnikova explained in a press release the beauty of this mechanism:

“The fact that cells sense what their neighbors are doing and do the exact opposite provides a very efficient and simple way to maintain tissue size, architecture and function.”

The research was picked up by Phys.Org on Tuesday and was published in Nature Cell Biology.

Stem cells respond differently to aging vs. injured muscle
From aging skin, we now move on to our aging and injured muscles, two topics I know oh too well as a late-to-the-game runner. Researchers at the Sanford Burnham Prebys Medical Discovery Institute (SBP) in La Jolla report a surprising discovery that muscle stem cells respond differently to aging versus injury. This important new insight could help guide future therapeutic strategies for repairing muscle injuries or disorders.

muscle stem cell

Muscle stem cell (pink with green outline) sits along a muscle fiber.
Image: Michael Rudnicki/OIRM

Muscle stem cells, also called satellite cells, make a small, dormant population of cells in muscle tissue that springs to life when muscle is in need of repair. It turns out that these stem cells are not identical clones of each other but instead are a diverse pool of cells.  To understand how the assortment of muscle stem cells might respond differently to the normal wear and tear of aging, versus damage due to injury or disease, the research team used a technology that tracks the fate of individual muscle stem cells within living mice.

The analysis showed a clear but unexpected result. In aging muscle, the muscle stem cells maintained their diversity but their ability to divide and grow declined. However, the opposite result was observed in injured muscle: the muscle stem cell diversity became limited but the capacity to divide was not affected. In a press release, team leader Alessandra Sacco explains the implications of these findings for therapy development:

sacco

Alessandra Sacco, PhD

“This study has shown clear-cut differences in the dynamics of muscle stem cell pools during the aging process compared to a sudden injury. This means that there probably isn’t a ‘one size fits all’ approach to prevent the decline of muscle stem cells. Therapeutic strategies to maintain muscle mass and strength in seniors will most likely need to differ from those for patients with degenerative diseases.”

This report was picked up yesterday by Eureka Alert and published in Cell Stem Cell.

Advertisements

Stem Cell Stories that Caught our Eye: Mini-Brains in the Spotlight

Here are the stem cell stories that caught our eye this week.

Two research photos really caught my eye this week and they happened to be of the same thing – mini-brains. Also referred to as brain organoids, mini-brains are tiny balls of nervous tissue grown from stem cells in the lab. They allow scientists to model early brain development and study how disease affects brain cells. Another awesome thing about mini-brains is how cool they look under a microscope.

Mini Brains Part 1

Mini-brain grown in a culture dish. (Photo by Collin Edington and Iris Lee, MIT)

I discovered the first photo in a blog by Dr. Francis Collins, the Director of the National Institutes of Health. He was featuring one of the winning images from the 2017 Koch Institute Image Awards at MIT. The mini-brain photo was taken by researchers Collin Edington and Iris Lee and took over 12 hours to make. Talk about dedication!

Collins revealed that growing mini-brains from stem cells is just the tip of the iceberg for this MIT team. The researchers have plans to grow other types of mini-organs and eventually combine them to make a “human on a chip”. This multi-organ technology will be extremely valuable for studying complex diseases like Alzheimer’s and Parkinson’s, which affect multiple systems in the body.

Mini Brains Part 2

Mini-brain. (Photo by Robert Krencik and Jessy Van Asperen)

The second photo of mini-brains is from a study published this week in Stem Cell Reports by researchers at the Houston Methodist Research Institute. The team has developed a more efficient and effective method for growing mini-brains from stem cells. Typically, the process takes weeks to grow the organoids and months to mature those organoids to the point where they develop the specific cell types and structures found in the human brain.

The Houston team found that maturing different types of brain cells from pluripotent stem cells separately and then combining these mature cells together produced mini-brains that more accurately represented the complexity of the human brain. The trick was to add the brain’s support cells, called astrocytes, to the mini-brains. The astrocytes effectively “accelerated the connections of the surrounding neurons.”

The studies first author, Robert Krencik, explained in a news release,

“We always felt like what we were doing in the lab was not precisely modeling how the cells act within the human brain. So, for the first time, when we put these cells together systematically, they dramatically changed their morphological complexity, size and shape. They look like cells as you would see them within the human brain, so now we can study cells in the lab in a more natural environment.”

Their method also cuts down the time it takes to make mini-brains which will hugely benefit neuroscience researchers who have passed on using mini-brains in their studies because of the cost and time it takes to grow them. Krencik explained,

“Normally, growing these 3-D mini brains takes months and years to develop. We have new techniques to pre-mature the cells separately and then combine them, and we found that within a few weeks they’re able to form mature interactions with each other. So, the length of time to get to that endpoint for studies is dramatically reduced with our system.”

The team plans to use this method to make patient-specific mini-brains from induced pluripotent stem cells to gain new insights into how disease affects the brain. They also hope to translate their mini-brain system into clinical trials to help patients regenerate brain damage or repair brain function.

Stem Cell Stories That Caught our Eye: Stem Cell Therapies for Stroke and Duchenne Muscular Dystrophy Patients

With the Thanksgiving holiday behind us, we’re back to the grind at CIRM. Here are two exciting CIRM-funded stem cell stories that happened while you were away.

Stanford Scientists Are Treating Stroke Patients with Stem Cells

Smithsonian Magazine featured the work of a CIRM-funded scientist in their December Magazine issue. The article, “A Neurosurgeon’s Remarkable Plan to Treat Stroke Victims with Stem Cells”, features Dr. Gary Steinberg, who is the Chair of Neurosurgery at Stanford Medical Center and the founder of the Stanford Stroke Center.

Gary Steinberg (Photo by Jonathan Sprague)

The brain and its 100 billion cells need blood, which carries oxygen and nutrients, to function. When that blood supply is cut off, brain cells start to die and patients experience a stroke. Stroke can happen in one of two ways: either by blood clots that block the arteries and blood vessels that send blood to the brain or by blood vessels that burst within the brain itself. Symptoms experienced by stroke victims vary based on the severity of the stroke, but often patients report experiencing numbness or paralysis in their limbs or face, difficulty walking, talking and understanding.

Steinberg and his team at Stanford are developing a stem cell treatment to help stroke patients. Steinberg believes that not all brain cells die during a stroke, but rather some brain cells become “dormant” and stop functioning instead. By transplanting stem cells derived from donated bone marrow into the brains of stroke patients, Steinberg thinks he can wake up these dormant cells much like how the prince wakens Sleeping Beauty from her century of enchanted sleep.

Basically, the transplanted cells act like a defibrillator for the dormant cells in the stroke-damaged area of the brain. Steinberg thinks that the transplanted cells secrete proteins that signal dormant brain cells to wake up and start functioning normally again, and that they also trigger a “helpful immune response” that prompts the brain to repair itself.

Sonia has seen first hand how a stroke can rob you of even your most basic abilities.

Steinberg tested this stem cell treatment in a small clinical trial back in 2013. 18 patients were treated and many of them showed improvements in their symptoms. The Smithsonian piece mentions a particular patient who had a remarkable response to the treatment. Sonia Olea Coontz, at age 32, suffered a stroke that robbed her of most of her speech and her ability to use her right arm and leg. After receiving Steinberg’s stem cell treatment, Sonia rapidly improved and was able to raise her arm above her head and gained most of her speech back. You can read more about her experience in our Stories of Hope.

In collaboration with a company called SanBio, Steinberg’s team is now testing this stem cell therapy in 156 stroke patients in a CIRM-funded phase 2 clinical trial. The trial will help answer the question of whether this treatment is safe and also effective in a larger group of patients.

The Smithsonian article, which I highly recommend reading, shared Steinberg’s future aspirations to pursue stem cell therapies for traumatic brain and spinal cord injuries as well as neurodegenerative diseases like Alzheimer’s, Parkinson’s and ALS.

 

Capricor Approved to Launch New Clinical Trial for Duchenne Muscular Dystrophy

On Wednesday, Capricor Therapeutics achieved an exciting milestone for its leading candidate CAP-1002 – a stem cell-based therapy developed to treat boys and young men with a muscle-wasting disease called Duchenne muscular dystrophy (DMD).

The Los Angeles-based company announced that it received approval from the US Food and Drug Administration (FDA) for their investigational new drug (IND) application to launch a new clinical trial called HOPE II that’s testing repeated doses of CAP-1002 cells in DMD patients. The cells are derived from donated heart tissue and are believed to release regenerative factors that strengthen heart and other muscle function in DMD patients.

Capricor is currently conducting a Phase 2 trial, called HOPE-1, that’s testing a single dose of CAP-1002 cells in 24 DMD patients. CIRM is funding this trial and you can learn more about it on our clinical dashboard website and watch a video interview we did with a young man who participated in the trial.

Earlier this year, the company shared encouraging, positive results from the HOPE-1 trial suggesting that the therapy was improving some heart function and upper limb movement six months after treatment and was well-tolerated in patients. The goal of the new trial will be to determine whether giving patients repeated doses of the cell therapy over time will extend the benefits in upper limb movement in DMD patients.

In a news release, Capricor President and CEO Dr. Linda Marbán shared her company’s excitement for the launch of their new trial and what this treatment could mean for DMD patients,

Linda Marban, CEO of Capricor Therapeutics

“The FDA’s clearance of this IND upon its initial submission is a significant step forward in our development of CAP-1002. While there are many clinical initiatives in Duchenne muscular dystrophy, this is one of the very few to focus on non-ambulant patients. These boys and young men are looking to maintain what function they have in their arms and hands and, based on our previous study, we think CAP-1002 may be able to do exactly that.”

Stories that caught our eye: How dying cells could help save lives; could modified blood stem cells reverse diabetes?; and FDA has good news for patients, bad news for rogue clinics

Gunsmoke

Growing up I loved watching old cowboy movies. Invariably the hero, even though mortally wounded, would manage to save the day and rescue the heroine and/or the town.

Now it seems some stem cells perform the same function, dying in order to save the lives of others.

Researchers at Kings College in London were trying to better understand Graft vs Host Disease (GvHD), a potentially fatal complication that can occur when a patient receives a blood stem cell transplant. In cases of GvHD, the transplanted donor cells turn on the patient and attack their healthy cells and tissues.

Some previous research had found that using bone marrow cells called mesenchymal stem cells (MSCs) had some success in combating GvHD. But it was unpredictable who it helped and why.

Working with mice, the Kings College team found that the MSCs were only effective if they died after being transplanted. It appears that it is only as they are dying that the MSCs engage with the individual’s immune system, telling it to stop attacking healthy tissues. The team also found that if they kill the MSCs just before transplanting them into mice, they were just as effective.

In a news article on HealthCanal, lead researcher Professor Francesco Dazzi, said the next step is to see if this will apply to, and help, people:

“The side effects of a stem cell transplant can be fatal and this factor is a serious consideration in deciding whether some people are suitable to undergo one. If we can be more confident that we can control these lethal complications in all patients, more people will be able to receive this life saving procedure. The next step will be to introduce clinical trials for patients with GvHD, either using the procedure only in patients with immune systems capable of killing mesenchymal stem cells, or killing these cells before they are infused into the patient, to see if this does indeed improve the success of treatment.”

The study is published in Science Translational Medicine.

Genetically modified blood stem cells reverse diabetes in mice (Todd Dubnicoff)

When functioning properly, the T cells of our immune system keep us healthy by detecting and killing off infected, damaged or cancerous cells in our body. But in the case of type 1 diabetes, a person’s own T cells turn against the body by mistakenly targeting and destroying perfectly normal islet cells in the pancreas, which are responsible for producing insulin. As a result, the insulin-dependent delivery of blood sugar to the energy-hungry organs is disrupted leading to many serious complications. Blood stem cell transplants have been performed to treat the disease by attempting to restart the immune system. The results have failed to provide a cure.

Now a new study, published in Science Translational Medicine, appears to explain why those previous attempts failed and how some genetic rejiggering could lead to a successful treatment for type 1 diabetes.

An analysis of the gene activity inside the blood stem cells of diabetic mice and humans reveals that these cells lack a protein called PD-L1. This protein is known to play an important role in putting the brakes on T cell activity. Because T cells are potent cell killers, it’s important for proteins like PD-L1 to keep the activated T cells in check.

Cell based image for t 1 diabetes

Credit: Andrea Panigada/Nancy Fliesler

Researchers from Boston Children’s Hospital hypothesized that adding back PD-L1 may prevent T cells from the indiscriminate killing of the body’s own insulin-producing cells. To test this idea, the research team genetically engineered mouse blood stem cells to produce the PD-L1 protein. Experiments with the cells in a petri dish showed that the addition of PD-L1 did indeed block the attack-on-self activity. And when these blood stem cells were transplanted into a diabetic mouse strain, the disease was reversed in most of the animals over the short term while a third of the mice had long-lasting benefits.

The researchers hope this targeting of PD-L1 production – which the researchers could also stimulate with pharmacological drugs – will contribute to a cure for type 1 diabetes.

FDA’s new guidelines for stem cell treatments

Gottlieb

FDA Commissioner Scott Gottlieb

Yesterday Scott Gottlieb, the Commissioner at the US Food and Drug Administration (FDA), laid out some new guidelines for the way the agency regulates stem cells and regenerative medicine. The news was good for patients, not so good for clinics offering unproven treatments.

First the good. Gottlieb announced new guidelines encouraging innovation in the development of stem cell therapies, and faster pathways for therapies, that show they are both safe and effective, to reach the patient.

At the same time, he detailed new rules that provide greater clarity about what clinics can do with stem cells without incurring the wrath of the FDA. Those guidelines detail the limits on the kinds of procedures clinics can offer and what ways they can “manipulate” those cells. Clinics that go beyond those limits could be in trouble.

In making the announcement Gottlieb said:

“To be clear, we remain committed to ensuring that patients have access to safe and effective regenerative medicine products as efficiently as possible. We are also committed to making sure we take action against products being unlawfully marketed that pose a potential significant risk to their safety. The framework we’re announcing today gives us the solid platform we need to continue to take enforcement action against a small number of clearly unscrupulous actors.”

Many of the details in the announcement match what CIRM has been pushing for some years. Randy Mills, our previous President and CEO, called for many of these changes in an Op Ed he co-wrote with former US Senator Bill Frist.

Our hope now is that the FDA continues to follow this promising path and turns these draft proposals into hard policy.

 

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.

cherqui

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 

MariaMillan-085_600px

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”.

Caught our eye: new Americans 4 Cures video, better mini-brains reveal Zika insights and iPSC recipes go head-to-head

How stem cell research gives patients hope (Karen Ring).
You can learn about the latest stem cell research for a given disease in seconds with a quick google search. You’ll find countless publications, news releases and blogs detailing the latest advancements that are bringing scientists and clinicians closer to understanding why diseases happen and how to treat or cure them.

But one thing these forms of communications lack is the personal aspect. A typical science article explains the research behind the study at the beginning and ends with a concluding statement usually saying how the research could one day lead to a treatment for X disease. It’s interesting, but not always the most inspirational way to learn about science when the formula doesn’t change.

However, I’ve started to notice that more and more, institutes and organizations are creating videos that feature the scientists/doctors that are developing these treatments AND the patients that the treatments could one day help. This is an excellent way to communicate with the public! When you watch and listen to a patient talk about their struggles with their disease and how there aren’t effective treatments at the moment, it becomes clear why funding and advancing research is important.

We have a great example of a patient-focused stem cell video to share with you today thanks to our friends at Americans for Cures, a non-profit organization that advocates for stem cell research. They posted a new video this week in honor of Stem Cell Awareness Day featuring patients and patient advocates responding to the question, “What does stem cell research give you hope for?”. Many of these patients and advocates are CIRM Stem Cell Champions that we’ve featured on our website, blog, and YouTube channel.

Americans for Cures is encouraging viewers to take their own stab at answering this important question by sharing a short message (on their website) or recording a video that they will share with the stem cell community. We hope that you are up for the challenge!

Mini-brains help uncover some of Zika’s secrets (Kevin McCormack).
One of the hardest things about trying to understand how a virus like Zika can damage the brain is that it’s hard to see what’s going on inside a living brain. That’s not surprising. It’s not considered polite to do an autopsy of someone’s brain while they are still using it.

Human organoid_800x533

Microscopic image of a mini brain organoid, showing layered neural tissue and different groups of neural stem cells (in blue, red and magenta) giving rise to neurons (green). Image: Novitch laboratory/UCLA

But now researchers at UCLA have come up with a way to mimic human brains, and that is enabling them to better understand how Zika inflicts damage on a developing fetus.

For years researchers have been using stem cells to help create “mini brain organoids”, essentially clusters of some of the cells found in the brain. They were helpful in studying some aspects of brain behavior but limited because they were very small and didn’t reflect the layered complexity of the brain.

In a study, published in the journal Cell Reports, UCLA researchers showed how they developed a new method of creating mini-brain organoids that better reflected a real brain. For example, the organoids had many of the cells found in the human cortex, the part of the brain that controls thought, speech and decision making. They also found that the different cells could communicate with each other, the way they do in a real brain.

They used these organoids to see how the Zika virus attacks the brain, damaging cells during the earliest stages of brain development.

In a news release, Momoko Watanabe, the study’s first author, says these new organoids can open up a whole new way of looking at the brain:

“While our organoids are in no way close to being fully functional human brains, they mimic the human brain structure much more consistently than other models. Other scientists can use our methods to improve brain research because the data will be more accurate and consistent from experiment to experiment and more comparable to the real human brain.”

iPSC recipes go head-to-head: which one is best?
In the ten years since the induced pluripotent stem cell (iPSC) technique was first reported, many different protocols, or recipes, for reprogramming adult cells, like skin, into iPSCs have been developed. These variations bring up the question of which reprogramming recipe is best. This question isn’t the easiest to answer given the many variables that one needs to test. Due to the cost and complexity of the methods, comparisons of iPSCs generated in different labs are often performed. But one analysis found significant lab-to-lab variability which can really muck up the ability to make a fair comparison.

A Stanford University research team, led by Dr. Joseph Wu, sought to eliminate these confounding variables so that any differences found could be attributed specifically to the recipe. So, they tested six different reprogramming methods in the same lab, using cells from the same female donor. And in turn, these cells were compared to a female source of embryonic stem cells, the gold standard of pluripotent stem cells. They reported their findings this week in Nature Biomedical Engineering.

Previous studies had hinted that the reprogramming protocol could affect the ability to fully specialize iPSCs into a particular cell type. But based on their comparisons, the protocol chosen did not have a significant impact on how well iPSCs can be matured. Differences in gene activity are a key way that researchers do side-by-side comparisons of iPSCs and embryonic stem cells. And based on the results in this study, the reprogramming method itself can influence the differences. A gene activity comparison of all the iPSCs with the embryonic stem cells found the polycomb repressive complex – a set of genes that play an important role in embryonic development and are implicated in cancer – had the biggest difference.

In a “Behind the Paper” report to the journal, first author Jared Churko, says that based on these findings, their lab now mostly uses one reprogramming protocol – which uses the Sendai virus to deliver the reprogramming genes to the cells:

“The majority of our hiPSC lines are now generated using Sendai virus. This is due to the ease in generating hiPSCs using this method as well as the little to no chance of transgene integration [a case in which a reprogramming gene inserts into the cells’ DNA which could lead to cancerous growth].”

Still, he adds a caveat that the virus does tend to linger in the cells which suggests that:

“cell source or reprogramming method utilized, each hiPSC line still requires robust characterization prior to them being used for downstream experimentation or clinical use.”

 

Stem Cell Stories That Caught Our Eye: Halting Brain Cancer, Parkinson’s disease and Stem Cell Awareness Day

Stopping brain cancer in its tracks.

Experiments by a team of NIH-funded scientists suggests a potential method for halting the expansion of certain brain tumors.Michelle Monje, M.D., Ph.D., Stanford University.

Scientists at Stanford Medicine discovered that you can halt aggressive brain cancers called high-grade gliomas by cutting off their supply of a signaling protein called neuroligin-3. Their research, which was funded by CIRM and the NIH, was published this week in the journal Nature. 

The Stanford team, led by senior author Michelle Monje, had previously discovered that neuroligin-3 dramatically spurred the growth of glioma cells in the brains of mice. In their new study, the team found that removing neuroligin-3 from the brains of mice that were transplanted with human glioma cells prevented the cancer cells from spreading.

Monje explained in a Stanford news release,

“We thought that when we put glioma cells into a mouse brain that was neuroligin-3 deficient, that might decrease tumor growth to some measurable extent. What we found was really startling to us: For several months, these brain tumors simply didn’t grow.”

The team is now exploring whether targeting neuroligin-3 will be an effective therapeutic treatment for gliomas. They tested two inhibitors of neuroligin-3 secretion and saw that both were effective in stunting glioma growth in mice.

Because blocking neuroligin-3 doesn’t kill glioma cells and gliomas eventually find ways to grow even in the absence of neuroligin-3, Monje is now hoping to develop a combination therapy with neuroligin-3 inhibitors that will cure patients of high-grade gliomas.

“We have a really clear path forward for therapy; we are in the process of working with the company that owns the clinically characterized compound in an effort to bring it to a clinical trial for brain tumor patients. We will have to attack these tumors from many different angles to cure them. Any measurable extension of life and improvement of quality of life is a real win for these patients.”

Parkinson’s Institute CIRM Research Featured on KTVU News.

The Bay Area Parkinson’s Institute and Clinical Center located in Sunnyvale, California, was recently featured on the local KTVU news station. The five-minute video below features patients who attend the clinic at the Parkinson’s Institute as well as scientists who are doing cutting edge research into Parkinson’s disease (PD).

Parkinson’s disease in a dish. Dopaminergic neurons made from PD induced pluripotent stem cells. (Image courtesy of Birgitt Schuele).

One of these scientists is Dr. Birgitt Schuele, who recently was awarded a discovery research grant from CIRM to study a new potential therapy for Parkinson’s using human induced pluripotent stem cells (iPSCs) derived from PD patients. Schuele explains that the goal of her team’s research is to “generate a model for Parkinson’s disease in a dish, or making a brain in a dish.”

It’s worth watching the video in its entirety to learn how this unique institute is attempting to find new ways to help the growing number of patients being diagnosed with this degenerative brain disease.

Click on photo to view video.

Mark your calendars for Stem Cell Awareness Day!

Every year on the second Wednesday of October is Stem Cell Awareness Day (SCAD). This is a day that our agency started back in 2009, with a proclamation by former California Mayor Gavin Newsom, to honor the important accomplishments made in the field of stem cell research by scientists, doctors and institutes around the world.

This year, SCAD is on October 11th. Our Agency will be celebrating this day with a special patient advocate event on Tuesday October 10th at the UC Davis MIND Institute in Sacramento California. CIRM grantees Dr. Jan Nolta, the Director of UC Davis Institute for Regenerative Cures, and Dr. Diana Farmer, Chair of the UC Davis Department of Surgery, will be talking about their CIRM-funded research developing stem cell models and potential therapies for Huntington’s disease and spina bifida (a birth defect where the spinal cord fails to fully develop). You’ll also hear an update on  CIRM’s progress from our President and CEO (Interim), Maria Millan, MD, and Chairman of the Board, Jonathan Thomas, PhD, JD. If you’re interested in attending this event, you can RSVP on our Eventbrite Page.

Be sure to check out a list of other Stem Cell Awareness Day events during the month of October on our website. You can also follow the hashtag #StemCellAwarenessDay on Twitter to join in on the celebration!

One last thing. October is an especially fun month because we also get to celebrate Pluripotency Day on October 4th. OCT4 is an important gene that maintains stem cell pluripotency – the ability of a stem cell to become any cell type in the body – in embryonic and induced pluripotent stem cells. Because not all stem cells are pluripotent (there are adult stem cells in your tissues and organs) it makes sense to celebrate these days separately. And who doesn’t love having more reasons to celebrate science?

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.

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).

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.

149147_web

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.”