UCLA scientists on track to develop a stem cell replacement therapy for Duchenne Muscular Dystrophy

Muscle cells generated by April Pyle’s Lab at UCLA.

Last year, we wrote about a CIRM-funded team at UCLA that’s on a mission to develop a stem cell treatment for patients with Duchenne muscular dystrophy (DMD). Today, we bring you an exciting update on this research just in time for the holidays (Merry Christmas and Happy Hanukkah and Kwanza to our readers!).

DMD is a deadly muscle wasting disease that primarily affects young boys and young men. The UCLA team is trying to generate better methods for making skeletal muscle cells from pluripotent stem cells to regenerate the muscle tissue that is lost in patients with the condition. DMD is caused by genetic mutations in the dystrophin gene, which codes for a protein that is essential for skeletal muscle function. Without dystrophin protein, skeletal muscles become weak and waste away.

In their previous study, the UCLA team used CRISPR gene editing technology to remove dystrophin mutations in induced pluripotent stem cells (iPSCs) made from the skin cells of DMD patients. These corrected iPSCs were then matured into skeletal muscle cells that were transplanted into mice. The transplanted muscle cells successfully produced dystrophin protein – proving for the first time that DMD mutations can be corrected using human iPSCs.

A Step Forward

The team has advanced their research a step forward and published a method for making skeletal muscle cells, from DMD patient iPSCs, that look and function like real skeletal muscle tissue. Their findings, which were published today in the journal Nature Cell Biology, address a longstanding problem in the field: not being able to make stem cell-derived muscle cells that are mature enough to model DMD or to be used for cell replacement therapies.

Dr. April Pyle, senior author on the study and Associate Professor at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA explained in a news release:

April Pyle, UCLA.

“We have found that just because a skeletal muscle cell produced in the lab expresses muscle markers, doesn’t mean it is fully functional. For a stem cell therapy for Duchenne to move forward, we must have a better understanding of the cells we are generating from human pluripotent stem cells compared to the muscle stem cells found naturally in the human body and during the development process.”

By comparing the proteins expressed on the cell surface of human fetal and adult muscle cells, the team identified two proteins, ERBB3 and NGFR, that represented a regenerative population of skeletal muscle cells. They used these two markers to isolate these regenerative muscle cells, but found that the muscle fibers they created in a lab dish were smaller than those found in human muscle.

First author, Michael Hicks, discovered that using a drug to block a human developmental signaling pathway called TGF Beta pushed these ERBB3/NGFR cells past this intermediate stage and allowed them to mature into functional skeletal muscle cells similar to those found in human muscle.

Putting It All Together

In their final experiments, the team combined the new stem cell techniques developed in the current study with their previous work using CRISPR gene editing technology. First, they removed the dystrophin mutations in DMD patient iPSCs using CRISPR. Then, they coaxed the iPSCs into skeletal muscle cells in a dish and isolated the regenerative cells that expressed ERBB3 and NGFR. Mice that lacked the dystrophin protein were then transplanted with these cells and were simultaneously given an injection of a TGF Beta blocking drug.

The results were exciting. The transplanted cells were able to produce human dystrophin and restore the expression of this protein in the Duchenne mice.

Skeletal muscle cells isolated using the ERBB3 and NGFR surface markers (right) restore human dystrophin (green) after transplantation significantly greater than previous methods (left). (Image courtesy of UCLA)

Dr. Pyle concluded,

“The results were exactly what we’d hoped. This is the first study to demonstrate that functional muscle cells can be created in a laboratory and restore dystrophin in animal models of Duchenne using the human development process as a guide.”

In the long term, the UCLA team hopes to translate this research into a patient-specific stem cell therapy for DMD patients. In the meantime, the team will use funding from a recent CIRM Quest award to make skeletal muscle cells that can regenerate long-term in response to chronic injury in hopes of developing a more permanent treatment for DMD.

The UCLA study discussed in this blog received funding from Discovery stage CIRM awards, which you can read more about here and here.

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CIRM interviews Lorenz Studer: 2017 recipient of the Ogawa-Yamanaka Stem Cell Prize [Video]

For eight long years, researchers who were trying to develop a stem cell-based therapy for Parkinson’s disease – an incurable movement disorder marked by uncontrollable shaking, body stiffness and difficulty walking – found themselves lost in the proverbial wilderness. In initial studies, rodent stem cells were successfully coaxed to specialize into dopamine-producing nerve cells, the type that are lost in Parkinson’s disease. And further animal studies showed these cells could treat Parkinson’s like symptoms when transplanted into the brain.

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Lorenz Studer, MD
Photo Credit: Sloan Kettering

But when identical recipes were used to make human stem cell-derived dopamine nerve cells the same animal experiments didn’t work. By examining the normal developmental biology of dopamine neurons much more closely, Lorenz Studer cracked the case in 2011. Now seven years later, Dr. Studer, director of the Center for Stem Cell Biology at the Memorial-Sloan Kettering Cancer Center, and his team are on the verge of beginning clinical trials to test their Parkinson’s cell therapy in patients

It’s for these bottleneck-busting contributions to the stem cell field that Dr. Studer was awarded the Gladstone Institutes’ 2017 Ogawa-Yamanaka Stem Cell Prize. Now in its third year, the prize was founded by philanthropists Hiro and Betty Ogawa along with  Shinya Yamanaka, Gladstone researcher and director of the Center for iPS Cell Research and Application at Kyoto University, and is meant to inspire and celebrate discoveries that build upon Yamanaka’s Nobel prize winning discovery of induced pluripotent stem cells (iPSCs).

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(L to R) Shinya Yamanaka, Andrew Ogawa, Deepak Srivastava present Lorenz Studer the 2017 Ogawa-Yamanaka Stem Cell Prize at Gladstone Institutes. Photo Credit: Todd Dubnicoff/CIRM

Studer was honored at the Gladstone in November and presented the Ogawa-Yamanka Stem Cell Prize Lecture. He was kind enough to sit down with me for a brief video interview (watch it below) a few minutes before he took the stage. He touched upon his Parkinson’s disease research as well as newer work related to hirschsprung disease, a dangerous intestinal disorder often diagnosed at birth that is caused by the loss of nerve cells in the gut. Using human embryonic stem cells and iPSCs derived from hirschsprung patients, Studer’s team has worked out the methods for making the gut nerve cells that are lost in the disease. This accomplishment has allowed his lab to better understand the disease and to make solid progress toward a stem cell-based therapy.

His groundbreaking work has also opened up the gates for other Parkinson’s researchers to make important insights in the field. In fact, CIRM is funding several interesting early stage projects aimed at moving therapy development forward:

We posted the 8-minute video with Dr. Studer today on our official YouTube channel, CIRM TV. You can watch the video here:

And for a more detailed description of Studer’s research, watch Gladstone’s webcast recording of his entire lecture:

Comparing two cellular reprogramming methods from one donor’s cells yields good news for iPSCs

In 2012, a mere six years after his discovery of induced pluripotent stem cells (iPSCs), Shinya Yamanaka was awarded the Nobel Prize in Medicine. Many Nobel winners aren’t recognized until decades after their initial groundbreaking studies. That goes to show you the importance of Yamanaka’s technique, which can reprogram a person’s cells, for example skin or blood, into embryonic stem cell-like iPSCs by just adding a small set of reprogramming factors.

These iPSCs are pluripotent, meaning they can be specialized, or differentiated, into virtually any cell type in the body. With these cells in hand, researchers have a powerful tool to study human disease and to develop treatments using human cells directly from patients. And at the same time, this cell source helps avoid the ethical concerns related to embryonic stem cells.

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Induced pluripotent stem cell (iPSC) colonies.
Image Credit: Joseph Wu

Still, there has been lingering uneasiness about how well iPSCs match up to embryonic stem cells (ESCs), considered the gold-standard of pluripotent stem cells. One source of those concerns is that the iPSC method doesn’t completely reprogram cells and they retain memory of their original cell source, in the form of chemical – also called epigenetic – modifications of the cells’ DNA structure. So, if a researcher were to make, say, heart muscle cells from iPSCs that have an epigenetic memory of its skin cell origins, any resulting conclusions about a given disease study or cell therapy could be less accurate than ESC-related results. But a report published yesterday in PNAS should help relieve these worries.

The CIRM-funded study – a collaboration between the labs of Joseph Wu and Michael Synder at Stanford University and Shoukhrat Mitalipov at Oregon Health & Science University – carried out an exhaustive series of experiments that carefully compared the gene activity and cell functions of iPSC-derived cells with cells derived from embryonic stem cells. The teams sought to compare cells generated from the same person to be sure any differences were not the result of genetics. To make this “apples-to-apples” comparison, they generated embryonic stem cells using another reprogramming technique called somatic cell nuclear transfer (SCNT).

With SCNT, a nucleus from an adult cell is transferred to an egg which has its own nucleus removed. The resulting cell becomes reprogrammed back into an embryo from which embryonic stem cells are generated – the researchers call them NT-ESCs for short. In this study, the skin cell sample used for making the iPSCs and the cell nucleus used for making the NT-ESCs came from the same person. In scientific lingo, the iPSCs and SCNT stem cells are considered isogenic.

Now, it turns out the NT-ESC reprogramming process is more complete and eliminates epigenetic memory of the original cell source. So why even bother with iPSCs if you have NT-ESCs? There are big disadvantages with SCNT: it’s a complex technique – only a limited number of labs pull it off – and it requires donated human eggs which carries ethical issues. So, if a direct comparison iPSCs and SNCT stem cells shows little difference then it would be fair to argue that iPSCs can replace NT-ESCs for deriving patient-specific stem cells.

And that’s exactly what the teams found, as Dr. Wu summarized it to me in an interview:

“Direct comparison between differentiated cells derived from iPSCs and SCNT had never been performed because it had been difficult to generate patient-specific ESCs by the SCNT method. Collaborating with Dr. Shoukhrat Mitalipov at Oregon Health & Science University and Dr. Michael Snyder at Stanford University, we compared patient-specific cardiomocytes (heart muscle cells) and endothelial (blood vessel) cells derived by these two reprogramming methods (SCNT and iPSCs) and found they were relatively equivalent regarding molecular and functional features.”

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Blood vessel cells derived by iPSC (left) and SCNT (right) reprogramming methods.
Image credit: Joseph Wu

Because the heart muscle and blood vessel cells were similar regardless of reprogramming method, it suggests that the epigenetic memory that remained in the iPSCs is less of a worry. Dr. Wu explained to me this way:

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Joseph Wu

“If iPSCs carry substantial epigenetic memory of the cell-of-origin, it is unlikely these iPSCs can differentiate to a functional cardiac cell or blood vessel cell. Only the stem cells free of significant epigenetic memory can differentiate into functional cells.”

 

Hopefully these results hold up over time because it will bode well for the countless iPSC-related disease studies as well as the growing number of iPSC-related projects that are nearing clinical trials.

Hey, what’s the big idea? CIRM Board is putting up more than $16.4 million to find out

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David Higgins, CIRM Board member and Patient Advocate for Parkinson’s disease; Photo courtesy San Diego Union Tribune

When you have a life-changing, life-threatening disease, medical research never moves as quickly as you want to find a new treatment. Sometimes, as in the case of Parkinson’s disease, it doesn’t seem to move at all.

At our Board meeting last week David Higgins, our Board member and Patient Advocate for Parkinson’s disease, made that point as he championed one project that is taking a new approach to finding treatments for the condition. As he said in a news release:

“I’m a fourth generation Parkinson’s patient and I’m taking the same medicines that my grandmother took. They work but not for everyone and not for long. People with Parkinson’s need new treatment options and we need them now. That’s why this project is worth supporting. It has the potential to identify some promising candidates that might one day lead to new treatments.”

The project is from Zenobia Therapeutics. They were awarded $150,000 as part of our Discovery Inception program, which targets great new ideas that could have a big impact on the field of stem cell research but need some funding to help test those ideas and see if they work.

Zenobia’s idea is to generate induced pluripotent stem cells (iPSCs) that have been turned into dopaminergic neurons – the kind of brain cell that is dysfunctional in Parkinson’s disease. These iPSCs will then be used to screen hundreds of different compounds to see if any hold potential as a therapy for Parkinson’s disease. Being able to test compounds against real human brain cells, as opposed to animal models, could increase the odds of finding something effective.

Discovering a new way

The Zenobia project was one of 14 programs approved for the Discovery Inception award. You can see the others on our news release. They cover a broad array of ideas targeting a wide range of diseases from generating human airway stem cells for new approaches to respiratory disease treatments, to developing a novel drug that targets cancer stem cells.

Dr. Maria Millan, CIRM’s President and CEO, said the Stem Cell Agency supports this kind of work because we never know where the next great idea is going to come from:

“This research is critically important in advancing our knowledge of stem cells and are the foundation for future therapeutic candidates and treatments. Exploring and testing new ideas increases the chances of finding treatments for patients with unmet medical needs. Without CIRM’s support many of these projects might never get off the ground. That’s why our ability to fund research, particularly at the earliest stage, is so important to the field as a whole.”

The CIRM Board also agreed to invest $13.4 million in three projects at the Translation stage. These are programs that have shown promise in early stage research and need funding to do the work to advance to the next level of development.

  • $5.56 million to Anthony Oro at Stanford to test a stem cell therapy to help people with a form of Epidermolysis bullosa, a painful, blistering skin disease that leaves patients with wounds that won’t heal.
  • $5.15 million to Dan Kaufman at UC San Diego to produce natural killer (NK) cells from embryonic stem cells and see if they can help people with acute myelogenous leukemia (AML) who are not responding to treatment.
  • $2.7 million to Catriona Jamieson at UC San Diego to test a novel therapeutic approach targeting cancer stem cells in AML. These cells are believed to be the cause of the high relapse rate in AML and other cancers.

At CIRM we are trying to create a pipeline of projects, ones that hold out the promise of one day being able to help patients in need. That’s why we fund research from the earliest Discovery level, through Translation and ultimately, we hope into clinical trials.

The writer Victor Hugo once said:

“There is one thing stronger than all the armies in the world, and that is an idea whose time has come.”

We are in the business of finding those ideas whose time has come, and then doing all we can to help them get there.

 

 

 

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

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

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

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

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

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

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

The study is published in the Journal of Comparative Neurology.

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

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

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

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

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

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

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

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

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

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

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

When CIRM was created in 2001, our goal was to grow the stem cell research field in California. But to do that, we first had to build some actual buildings. Since then, our infrastructure programs have taken on many different forms, but all have been focused on a single mission – helping accelerate stem cell research to patients with unmet medical needs.
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In the early 2000’s, stem cell scientists faced a quandary. President George W. Bush had placed limits on how federal funds could be used for embryonic stem cell research. His policy allowed funding of research involving some existing embryonic stem cell lines, but banned research that developed or conducted research on new stem lines.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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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?

Bioengineers make breathtaking step toward building a lung

Tissue engineers have made amazing progress when it comes to using stem cells to build tissues such as blood vessels, which have relatively simple tubular shape. In fact, a late stage CIRM-funded clinical trial run by Humacyte is testing an engineered vein to improve dialysis treatment for people with kidney disease. Building a lung that works properly, on the other hand, has proven elusive due in no small part to its extremely intricate structure. But in a Science Advances report published yesterday, Columbia University bioengineers describe a potentially breakthrough method for building a functional lung in the lab.

Building a better lung that removes and repopulates lung cells without hurting blood vessels. Figure courtesy of N. Valerio Dorrello and Gordana Vunjak-Novakovic, Columbia University.

Lung disease tends to not get as much attention as other deadly diseases like cancer and heart failure. Yet it’s the world’s third leading cause of death with 400,000 deaths per year in just the United States. The only true treatment is a very drastic one: a lung transplant. This option is not very attractive even to those with severe disease because it’s a very expensive procedure that only has a 10-20% survival rate after 10 years. On top of that, donor lungs are in very short supply. So, clinicians and their patients are in desperate need for other approaches.

Tissue engineering approaches to building a lung face many challenges due to the organ’s complex structure. How complex, you ask? Science writer and scientist, Shelly Fan, uses a great analogy to describe it in her Singularity Hub article about this study:

“The lung is a real jungle: at the microscopic level, the tree-like airways contain alveoli, tiny bubble-like structures where the lungs exchange gas with our blood. Both arteries and veins enwrap the alveoli like two sets of mesh pockets.”

Now, one approach to building an organ is to start from scratch by manufacturing a synthetic scaffold resembling the shape of the organ and then seeding it with stem cells or other precursor cells. But because of this complicated microscopic jungle, bioengineers have steered clear of this path. Instead, the Columbia team has generated a natural scaffold by removing the cells from rat lungs using detergents. What’s left behind is a lung “skeleton” of proteins and molecules called the extracellular matrix that’s devoid of cells.

Building a better lung that removes and repopulates lung cells without hurting blood vessels. Figure courtesy of N. Valerio Dorrello and Gordana Vunjak-Novakovic, Columbia University.

In previous experiments using rat lungs, the team stripped out the lung cells, called epithelial cells, which are the type typically damaged in lung disease. Their method also removed the blood vessel cells, called endothelial cells, which make up the vascular system that is key to taking up the oxygen inhaled into the lungs. While repopulating the functional epithelial cells has been achieved, restoring the blood vessels is another story as mentioned in a university press release:

“An intact vascular network—missing in these scaffolds—is critical not only for maintaining the blood-gas barrier and allowing for proper graft function, but also for supporting the cells introduced to regenerate the lung. This has proved to be a daunting challenge.”

So, the current study attempted to only clear out the lung epithelial cells without disturbing the blood vessels to see if they would have better results. This approach makes sense on another level when envisioning future clinical applications: the therapy would be less complex if you only had to remove the diseased cells, which typically are the lung epithelial cells.

The researchers devised a cell removal method that was specific to the airways so that only epithelial cells would be cleared away. A battery of tests showed that, that although the lungs lost much of their ability to inflate and expand, the blood system remained intact after the procedure. The team then introduced either human epithelial cells or human induced pluripotent stem cell-derived epithelial cells into the scaffold. Within a day, they watched as the cells began to repopulate the lung in the correct areas. Follow-up experiments showed that the addition of new epithelial cells restored a good portion of the lungs expansion abilities.

Lead author, Dr. N. Valerio Dorrello, gave a big picture perspective on how this proof-of-concept study could one day help those who suffer from lung disease:

Nicolino Valerio Dorrello, MD

“Every day, I see children in intensive care with severe lung disease who depend on mechanical ventilation support. The approach we established could lead to entirely new treatment modalities for these patients, designed to regenerate lungs by treating their injured epithelium.”

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!