Stem cell stories that caught our eye: developing the nervous system, aging stem cells and identical twins not so identical

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

New theory for how the nervous system develops.

There’s a new theory on the block for how the nervous system is formed thanks to a study published yesterday by UCLA stem cell scientists in the journal Neuron.

The theory centers around axons, thin extensions projecting from nerve cells that transmit electrical signals to other cells in the body. In the developing nervous system, nerve cells extend axons into the brain and spinal cord and into our muscles (a process called innervation). Axons are guided to their final destinations by different chemicals that tell axons when to grow, when to not grow, and where to go.

Previously, scientists believed that one of these important chemical signals, a protein called netrin 1, exerted its influence over long distances in a gradient-like fashion from a structure in the developing nervous system called the floor plate. You can think of it like a like a cell phone tower where the signal is strongest the closer you are to the tower but you can still get some signal even when you’re miles away.

The UCLA team questioned this theory because they knew that neural progenitor cells, which are the precursors to nerve cells, produce netrin1 in the developing spinal cord. They believed that the netrin1 secreted from these progenitor cells also played a role in guiding axon growth in a localized manner.

To test their hypothesis, they studied neural progenitor cells in the developing spines of mouse embryos. When they eliminated netrin1 from the neural progenitor cells, the axons went haywire and there was no rhyme or reason to their growth patterns.

Left: axons (green, pink, blue) form organized patterns in the normal developing mouse spinal cord. Right: removing netrin1 results in highly disorganized axon growth. (UCLA Broad Stem Cell Research Center/Neuron)

A UCLA press release explained what the scientists discovered next,

“They found that neural progenitors organize axon growth by producing a pathway of netrin1 that directs axons only in their local environment and not over long distances. This pathway of netrin1 acts as a sticky surface that encourages axon growth in the directions that form a normal, functioning nervous system.”

Like how ants leave chemical trails for other ants in their colony to follow, neural progenitor cells leave trails of netrin1 in the spinal cord to direct where axons go. The UCLA team believes they can leverage this newfound knowledge about netrin1 to make more effective treatments for patients with nerve damage or severed nerves.

In future studies, the team will tease apart the finer details of how netrin1 impacts axon growth and how it can be potentially translated into the clinic as a new therapeutic for patients. And from the sounds of it, they already have an idea in mind:

“One promising approach is to implant artificial nerve channels into a person with a nerve injury to give regenerating axons a conduit to grow through. Coating such nerve channels with netrin1 could further encourage axon regrowth.”

Age could be written in our stem cells.

The Harvard Gazette is running an interesting series on how Harvard scientists are tackling issues of aging with research. This week, their story focused on stem cells and how they’re partly to blame for aging in humans.

Stem cells are well known for their regenerative properties. Adult stem cells can rejuvenate tissues and organs as we age and in response to damage or injury. However, like most house hold appliances, adult stem cells lose their regenerative abilities or effectiveness over time.

Dr. David Scadden, co-director of the Harvard Stem Cell Institute, explained,

“We do think that stem cells are a key player in at least some of the manifestations of age. The hypothesis is that stem cell function deteriorates with age, driving events we know occur with aging, like our limited ability to fully repair or regenerate healthy tissue following injury.”

Harvard scientists have evidence suggesting that certain tissues, such as nerve cells in the brain, age sooner than others, and they trigger other tissues to start the aging process in a domino-like effect. Instead of treating each tissue individually, the scientists believe that targeting these early-onset tissues and the stem cells within them is a better anti-aging strategy.

David Sadden, co-director of the Harvard Stem Cell Institute.
(Jon Chase/Harvard Staff Photographer)

Dr. Scadden is particularly interested in studying adult stem cell populations in aging tissues and has found that “instead of armies of similarly plastic stem cells, it appears there is diversity within populations, with different stem cells having different capabilities.”

If you lose the stem cell that’s the best at regenerating, that tissue might age more rapidly.  Dr. Scadden compares it to a game of chess, “If we’re graced and happen to have a queen and couple of bishops, we’re doing OK. But if we are left with pawns, we may lose resilience as we age.”

The Harvard Gazette piece also touches on a changing mindset around the potential of stem cells. When stem cell research took off two decades ago, scientists believed stem cells would grow replacement organs. But those days are still far off. In the immediate future, the potential of stem cells seems to be in disease modeling and drug screening.

“Much of stem cell medicine is ultimately going to be ‘medicine,’” Scadden said. “Even here, we thought stem cells would provide mostly replacement parts.  I think that’s clearly changed very dramatically. Now we think of them as contributing to our ability to make disease models for drug discovery.”

I encourage you to read the full feature as I only mentioned a few of the highlights. It’s a nice overview of the current state of aging research and how stem cells play an important role in understanding the biology of aging and in developing treatments for diseases of aging.

Identical twins not so identical (Todd Dubnicoff)

Ever since Takahashi and Yamanaka showed that adult cells could be reprogrammed into an embryonic stem cell-like state, researchers have been wrestling with a key question: exactly how alike are these induced pluripotent stem cells (iPSCs) to embryonic stem cells (ESCs)?

It’s an important question to settle because iPSCs have several advantages over ESCs. Unlike ESCs, iPSCs don’t require the destruction of an embryo so they’re mostly free from ethical concerns. And because they can be derived from a patient’s cells, if iPSC-derived cell therapies were given back to the same patient, they should be less likely to cause immune rejection. Despite these advantages, the fact that iPSCs are artificially generated by the forced activation of specific genes create lingering concerns that for treatments in humans, delivering iPSC-derived therapies may not be as safe as their ESC counterparts.

Careful comparisons of DNA between iPSCs and ESCs have shown that they are indeed differences in chemical tags found on specific spots on the cell’s DNA. These tags, called epigenetic (“epi”, meaning “in addition”) modifications can affect the activity of genes independent of the underlying genetic sequence. These variations in epigenetic tags also show up when you compare two different preparations, or cell lines, of iPSCs. So, it’s been difficult for researchers to tease out the source of these differences. Are these differences due to the small variations in DNA sequence that are naturally seen from one cell line to the other? Or is there some non-genetic reason for the differences in the iPSCs’ epigenetic modifications?

Marian and Vivian Brown, were San Francisco’s most famous identical twins. Photo: Christopher Michel

A recent CIRM-funded study by a Salk Institute team took a clever approach to tackle this question. They compared epigenetic modifications between iPSCs derived from three sets of identical twins. They still found several epigenetic variations between each set of twins. And since the twins have identical DNA sequences, the researchers could conclude that not all differences seen between iPSC cell lines are due to genetics. Athanasia Panopoulos, a co-first author on the Cell Stem Cell article, summed up the results in a press release:

“In the past, researchers had found lots of sites with variations in methylation status [specific term for the epigenetic tag], but it was hard to figure out which of those sites had variation due to genetics. Here, we could focus more specifically on the sites we know have nothing to do with genetics. The twins enabled us to ask questions we couldn’t ask before. You’re able to see what happens when you reprogram cells with identical genomes but divergent epigenomes, and figure out what is happening because of genetics, and what is happening due to other mechanisms.”

With these new insights in hand, the researchers will have a better handle on interpreting differences between individual iPSC cell lines as well as their differences with ESC cell lines. This knowledge will be important for understanding how these variations may affect the development of future iPSC-based cell therapies.

Could revving up stem cells help senior citizens heal as fast as high school seniors?

All physicians, especially surgeons, sport medicine doctors, and military medical corps share a similar wish: to able to speed up the healing process for their patients’ incisions and injuries. Data published this week in Cell Reports may one day fulfill that wish. The study – reported by a Stanford University research team – pinpoints a single protein that revs up stem cells in the body, enabling them to repair tissue at a quicker rate.

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Muscle fibers (dark areas surrounding by green circles) are larger in mice injected with HGFA protein (right panel) compared to untreated mice (left panel), an indication of faster healing after muscle injury.
(Image: Cell Reports 19 (3) p. 479-486, fig 3C)

Most of the time, adult stem cells in the body keep to themselves and rarely divide. This calmness helps preserve this important, small pool of cells and avoids unnecessary mutations that may happen whenever DNA is copied during cell division.

To respond to injury, stem cells must be primed by dividing one time, which is a very slow process and can take several days. Once in this “alert” state, the stem cells are poised to start dividing much faster and help repair damaged tissue. The Stanford team, led by Dr. Thomas Rando, aimed to track down the signals that are responsible for this priming process with the hope of developing drugs that could help jump-start the healing process.

Super healing serum: it’s not just in video games
The team collected blood serum from mice two days after the animals had been subjected to a muscle injury (the mice were placed under anesthesia during the procedure and given pain medication afterwards). When that “injured” blood was injected into a different set of mice, their muscle stem cells became primed much faster than mice injected with “uninjured” blood.

“Clearly, blood from the injured animal contains a factor that alerts the stem cells,” said Rando in a press release. “We wanted to know, what is it in the blood that is doing this?”

 

A deeper examination of the priming process zeroed in on a muscle stem cell signal that is turned on by a protein in the blood called hepatocyte growth factor (HGF). So, it seemed likely that HGF was the protein that they had been looking for. But, to their surprise, there were no differences in the amount of HGF found in blood from injured and uninjured mice.

HGFA: the holy grail of healing?
It turns out, though, that HGF must first be chopped in two by an enzyme called HGFA to become active. When the team went back and examined the injured and uninjured blood, they found that it was HGFA which showed a difference: it was more active in the injured blood.

To show that HGFA was directly involved in stimulating tissue repair, the team injected mice with the enzyme two days before the muscle injury procedure. Twenty days post injury, the mice injected with HGFA had regenerated larger muscle fibers compared to untreated mice. Even more telling, nine days after the HGFA treatment, the mice had better recovery in terms of their wheel running activity compared to untreated mice.

To mimic tissue repair after a surgery incision, the team also looked at the impact of HGFA on skin wound healing. Like the muscle injury results, injecting animals with HGFA two days before creating a skin injury led to better wound healing compared to untreated mice. Even the hair that had been shaved at the surgical site grew back faster. First author Dr. Joseph Rodgers, now at USC, summed up the clinical implications of these results :

“Our research shows that by priming the body before an injury you can speed the process of tissue repair and recovery, similar to how a vaccine prepares the body to fight infection. We believe this could be a therapeutic approach to improve recovery in situations where injuries can be anticipated, such as surgery, combat or sports.”

Could we help senior citizens heal as fast as high school seniors?
Another application for this therapeutic approach may be for the elderly. Lots of things slow down when you get older including your body’s ability to heal itself. This observation sparks an intriguing question for Rando:

“Stem cell activity diminishes with advancing age, and older people heal more slowly and less effectively than younger people. Might it be possible to restore youthful healing by activating this [HGFA] pathway? We’d love to find out.”

I bet a lot of people would love for you to find out, too.

jCyte starts second phase of stem cell clinical trial targeting vision loss

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How retinitis pigmentosa destroys vision

Studies show that Americans fear losing their vision more than any other sense, such as hearing or speech, and almost as much as they fear cancer, Alzheimer’s and HIV/AIDS. That’s not too surprising. Our eyes are our connection to the world around us. Sever that connection, and the world is a very different place.

For people with retinitis pigmentosa (RP), the leading cause of inherited blindness in the world, that connection is slowly destroyed over many years. The disease eats away at the cells in the eye that sense light, so the world of people with RP steadily becomes darker and darker, until the light goes out completely. It often strikes people in their teens, and many are blind by the time they are 40.

There are no treatments. No cures. At least not yet. But now there is a glimmer of hope as a new clinical trial using stem cells – and funded by CIRM – gets underway.

klassenWe have talked about this project before. It’s run by UC Irvine’s Dr. Henry Klassen and his team at jCyte. In the first phase of their clinical trial they tested their treatment on a small group of patients with RP, to try and ensure that their approach was safe. It was. But it was a lot more than that. For people like Rosie Barrero, the treatment seems to have helped restore some of their vision. You can hear Rosie talk about that in our recent video.

Now the same treatment that helped Rosie, is going to be tested in a much larger group of people, as jCyte starts recruiting 70 patients for this new study.

In a news release announcing the start of the Phase 2 trial, Henry Klassen said this was an exciting moment:

“We are encouraged by the therapy’s excellent safety track record in early trials and hope to build on those results. Right now, there are no effective treatments for retinitis pigmentosa. People must find ways to adapt to their vision loss. With CIRM’s support, we hope to change that.”

The treatment involves using retinal progenitor cells, the kind destroyed by the disease. These are injected into the back of the eye where they release factors which the researchers hope will help rescue some of the diseased cells and regenerate some replacement ones.

Paul Bresge, CEO of jCyte, says one of the lovely things about this approach, is its simplicity:

“Because no surgery is required, the therapy can be easily administered. The entire procedure takes minutes.”

Not everyone will get the retinal progenitor cells, at least not to begin with. One group of patients will get an injection of the cells into their worst-sighted eye. The other group will get a sham injection with no cells. This will allow researchers to compare the two groups and determine if any improvements in vision are due to the treatment or a placebo effect.

The good news is that after one year of follow-up, the group that got the sham injection will also be able to get an injection of the real cells, so that if the therapy is effective they too may be able to benefit from it.

Rosie BarreroWhen we talked to Rosie Barrero about the impact the treatment had on her, she said it was like watching the world slowly come into focus after years of not being able to see anything.

“My dream was to see my kids. I always saw them with my heart, but now I can see them with my eyes. Seeing their faces, it’s truly a miracle.”

We are hoping this Phase 2 clinical trial gives others a chance to experience similar miracles.


Related Articles:

Listening is fine. Action is better. Why patients want more than just a chance to have their say.

FDA

Type in the phrase “the power of the patient voice” in any online search engine and you’ll generate thousands of articles and posts about the importance of listening to what patients have to say. The articles are on websites run by a diverse group from patients and researchers, to advocacy organizations and pharmaceutical companies. Everyone it seems recognizes the importance of listening to what the patient says. Even the Food and Drug Administration (FDA) has gotten in on the act. But what isn’t as clear is does all that talking and listening lead to any action?

In the last few years the FDA launched its ‘Patient-Focused Drug Development Initiative’, a series of public meetings where FDA officials invited patients and patient advocates to a public meeting to offer their perspectives on their condition and the available therapies. Each meeting focused on a different disease or condition, 20 in all, ranging from Parkinson’s and breast cancer to Huntington’s and sickle cell disease.

The meetings followed a standard format. Patients and patient advocates were invited to talk about the disease in question and its impact on their life, and then to comment on the available treatments and what they would like to see happen that could make their life better.

The FDA then gathered all those observations and comments, including some submitted online, and put them together in a report. Here’s where you can find all 20 FDA Voice of the Patient reports.  The reports all end with a similar concluding paragraph. Here’s what the conclusion for the Parkinson’s patient report said:

“The insight provided during this meeting will aid in FDA’s understanding of what patients truly value in a treatment and inform the agency’s evaluation of the benefits and risk of future treatments for Parkinson’s disease patients.”

And now what? That’s the question many patients and patient advocates are asking. I spoke with several people who were involved in these meetings and all came away feeling that the FDA commissioners who held the hearings were sincere and caring. But none believe it has made any difference, that it has led to any changes in policy.

For obvious reasons none of those I spoke to wanted to be identified. They don’t want to do anything that could in any way jeopardize a potential treatment for their condition. But many felt the hearings were just window dressing, that the FDA held them because it was required by Congress to do so. The Ageny, however, is not required to act on the conclusions or make any changes based on the hearings. And that certainly seems to be what’s happened.

Producing a report is fine. But if that report then gets put on a shelf and ignored what is the value of it? Patients and patient advocates want their voices to be heard. But more importantly they want what they say to lead to some action, to have some positive outcome. Right now they are wondering if they were invited to speak, but no one was really listening.

 

 

Stem Cell Stories That Caught Our Eye: Free Patient Advocate Event in San Diego, and new clues on how to fix muscular dystrophy and Huntington’s disease

UCSD Patient Advocate mtg instagram

Stem cell research is advancing so fast that it’s sometimes hard to keep up. That’s one of the reasons we have our Friday roundup, to let you know about some fascinating research that came across our desk during the week that you might otherwise have missed.

Of course, another way to keep up with the latest in stem cell research is to join us for our free Patient Advocate Event at UC San Diego next Thursday, April 20th from 12-1pm.  We are going to talk about the progress being made in stem cell research, the problems we still face and need help in overcoming, and the prospects for the future.

We have four great speakers:

  • Catriona Jamieson, Director of the CIRM UC San Diego Alpha Stem Cell Clinic and an expert on cancers of the blood
  • Jonathan Thomas, PhD, JD, Chair of CIRM’s Board
  • Jennifer Briggs Braswell, Executive Director of the Sanford Stem Cell Clinical Center
  • David Higgins, Patient Advocate for Parkinson’s on the CIRM Board

We will give updates on the exciting work taking place at UCSD and the work that CIRM is funding. We have also set aside some time to get your thoughts on how we can improve the way we work and, of course, answer your questions.

What: Stem Cell Therapies and You: A Special Patient Advocate Event

When: Thursday, April 20th 12-1pm

Where: The Sanford Consortium for Regenerative Medicine, 2880 Torrey Pines Scenic Drive, La Jolla, CA 92037

Why: Because the people of California have a right to know how their money is helping change the face of regenerative medicine

Who: This event is FREE and open to everyone.

We have set up an EventBrite page for you to RSVP and let us know if you are coming. And, of course, feel free to share this with anyone you think might be interested.

This is the first of a series of similar Patient Advocate Update meetings we plan on holding around California this year. We’ll have news on other locations and dates shortly.

 

Fixing a mutation that causes muscular dystrophy (Karen Ring)

It’s easy to take things for granted. Take your muscles for instance. How often do you think about them? (Don’t answer this if you’re a body builder). Daily? Monthly? I honestly don’t think much about my muscles unless I’ve injured them or if they’re sore from working out.

duchennes-cardiomyocytes-body

Heart muscle cells (green) that don’t have dystrophin protein (Photo; UT Southwestern)

But there are people in this world who think about their muscles or their lack of them every day. They are patients with a muscle wasting disease called Duchenne muscular dystrophy (DMD). It’s the most common type of muscular dystrophy, and it affects mainly young boys – causing their muscles to progressively weaken to the point where they cannot walk or breathe on their own.

DMD is caused by mutations in the dystrophin gene. These mutations prevent muscle cells from making dystrophin protein, which is essential for maintaining muscle structure. Scientists are using gene editing technologies to find and fix these mutations in hopes of curing patients of DMD.

Last year, we blogged about a few of these studies where different teams of scientists corrected dystrophin mutations using CRISPR/Cas9 gene editing technology in human cells and in mice with DMD. One of these teams has recently followed up with a new study that builds upon these earlier findings.

Scientists from UT Southwestern are using an alternative form of the CRISPR gene editing complex to fix dystrophin mutations in both human cells and mice. This alternative CRISPR complex makes use of a different cutting enzyme, Cpf1, in place of the more traditionally used Cas9 protein. It’s a smaller protein that the scientists say can get into muscle cells more easily. Cpf1 also differs from Cas9 in what DNA nucleotide sequences it recognizes and latches onto, making it a new tool in the gene editing toolbox for scientists targeting DMD mutations.

gene-edited-cardiomyocytes-body.jpg

Gene-edited heart muscle cells (green) that now express dystrophin protein (Photo: UT Southwestern)

Using CRISPR/Cpf1, the scientists corrected the most commonly found dystrophin mutation in human induced pluripotent stem cells derived from DMD patients. They matured these corrected stem cells into heart muscle cells in the lab and found that they expressed the dystrophin protein and functioned like normal heart cells in a dish. CRISPR/Cpf1 also corrected mutations in DMD mice, which rescued dystrophin expression in their muscle tissues and some of the muscle wasting symptoms caused by the disease.

Because the dystrophin gene is one of the longest genes in our genome, it has more locations where DMD-causing mutations could occur. The scientists behind this study believe that CRISPR/Cpf1 offers a more flexible tool for targeting different dystrophin mutations and could potentially be used to develop an effective gene therapy for DMD.

Senior author on the study, Dr. Eric Olson, provided this conclusion about their research in a news release by EurekAlert:

“CRISPR-Cpf1 gene-editing can be applied to a vast number of mutations in the dystrophin gene. Our goal is to permanently correct the underlying genetic causes of this terrible disease, and this research brings us closer to realizing that end.”

 

A cellular traffic jam is the culprit behind Huntington’s disease

Back in the 1983, the scientific community cheered the first ever mapping of a genetic disease to a specific area on a human chromosome which led to the isolation of the disease gene in 1993. That disease was Huntington’s, an inherited neurodegenerative disorder that typically strikes in a person’s thirties and leads to death about 10 to 15 years later. Because no effective therapy existed for the disease, this discovery of Huntingtin, as the gene was named, was seen as a critical step toward a better understand of Huntington’s and an eventual cure.

But flash forward to 2017 and researchers are still foggy on how mutations in the Huntingtin gene cause Huntington’s. New research, funded in part by CIRM, promises to clear some things up. The report, published this week in Neuron, establishes a connection between mutant Huntingtin and its impact on the transport of cell components between the nucleus and cytoplasm.

Roundup Picture1

The pores in the nuclear envelope allows proteins and molecules to pass between a cell’s nucleus and it’s cytoplasm. Image: Blausen.com staff (2014).

To function smoothly, a cell must be able to transport proteins and molecules in and out of the nucleus through holes called nuclear pores. The research team – a collaboration of scientists from Johns Hopkins University, the University of Florida and UC Irvine – found that in nerve cells, the mutant Huntingtin protein clumps up and plays havoc on the nuclear pore structure which leads to cell death. The study was performed in fly and mouse models of HD, in human HD brain samples as well as HD patient nerve cells derived with the induced pluripotent stem cell technique – all with this same finding.

Roundup Picture2

Huntington’s disease is caused by the loss of a nerve cells called medium spiny neurons. Image: Wikimedia commons

By artificially producing more of the proteins that make up the nuclear pores, the damaging effects caused by the mutant Huntingtin protein were reduced. Similar results were seen using drugs that help stabilize the nuclear pore structure. The implications of these results did not escape George Yohrling, a senior director at the Huntington’s Disease Society of America, who was not involved in the study. Yohrling told Baltimore Sun reporter Meredith Cohn:

“This is very exciting research because we didn’t know what mutant genes or proteins were doing in the body, and this points to new areas to target research. Scientists, biotech companies and pharmaceutical companies could capitalize on this and maybe develop therapies for this biological process”,

It’s important to temper that excitement with a reality check on how much work is still needed before the thought of clinical trials can begin. Researchers still don’t understand why the mutant protein only affects a specific type of nerve cells and it’s far from clear if these drugs would work or be safe to use in the context of the human brain.

Still, each new insight is one step in the march toward a cure.

A life-threatening childhood disease and the CIRM-funded team seeking a stem cell cure featured in new video

“My hope for Brooke is she can one day look back and we have to remind her of the disease she once had.”

That’s Clay Emerson’s biggest hope for his young daughter Brooke, who has cystinosis, a life-threatening genetic disease that appears by the age of two and over time causes damage to many organs, especially the kidneys and eyes but also the liver, muscle, brain, pancreas and other tissues. The Emersons and other families affected by the disease are featured in a recent video produced by the Cystinosis Research Foundation.

I doubt many can watch the seven-minute piece without getting a lump in their throat or watery eyes. One of many heart wrenching scene shows Brooke’s mother, Jill Emerson, preparing a day’s worth of medicine that she administers through a tube connected to Brook’s stomach.

“Brooke takes about 20 doses of medication a day and that’s throughout the 24hr period in a day. The poor kid hasn’t had a full night’s sleep ever in her entire life because I have to wake her up to take her life-saving medicine.”

Jill Emerson prepares a day’s worth of medicine for her daughter Brooke. Unfortunately, the treatments only slow the progression of cystinosis but don’t cure it. (Video Still: Cystinosis Research Foundation)

But these treatments only slow down the progression of this incurable disease. Even perfect compliance with taking the medicine doesn’t stop severe complications of the disease including kidney failure, diabetes, muscle weakness, and difficulty swallowing just to name a few. Cystinosis also shorten life spans. Natalie, the video’s narrator, a young woman with cystinosis wonders how much time she has left:

“There are people in their 20s who have recently died from cystinosis. I am 25 years old and I often think about how long I have to live. I’m praying for a cure for all of us.”

Her prayers may be answered in the form of a stem cell gene therapy treatment. UCSD researcher Dr. Stephanie Cherqui, who is also featured in the video, received $5 million in CIRM funding to bring her team’s therapy to clinical trials in people.

At a cellular level, cystinosis is caused by mutations in a gene called CTNS which lead to an accumulation of the amino acid cysteine. The excess cysteine eventually forms crystals causing devastating damage to cells throughout the body. Cherqui’s treatment strategy is to take blood stem cells from affected individuals, insert a good copy of the CTNS gene using genome editing into the cells’ DNA, and then transplant the cells back into the patient.

Cystinosis_Cherqui

Dr. Stephanie Cherqui and her team are working hard to bring a stem cell gene therapy treatment for cystinosis to clinical trials. (Video Still: Cystinosis Research Foundation)

Her team has preliminary evidence that the strategy works in mice. Now, they will use the CIRM grant to complete these pre-clinical studies and prepare the genetically engineered blood stem cells for use in patients. These steps are necessary to get the green light from the Food and Drug Administration (FDA) to begin clinical trials, hopefully some time this year.

Cherqui says that if all goes well, the treatment approach may have benefits beyond cystinosis:

“If we can bring this to the finish line, we can then show the way to maybe hundreds, maybe thousands of other genetic diseases. So this could be a real benefit to mankind.”

Creating partnerships to help get stem cell therapies over the finish line

Lewis, Clark, Sacagawea

Lewis & Clark & Sacagawea:

Trying to go it alone is never easy. Imagine how far Lewis would have got without Clark, or the two of them without Sacagawea. Would Batman have succeeded without Robin; Mickey without Minnie Mouse? Having a partner whose skills and expertise complements yours just makes things easier.

That’s why some recent news about two CIRM-funded companies running clinical trials was so encouraging.

Viacyte Gore

First ViaCyte, which is developing an implantable device to help people with type 1 diabetes, announced a collaborative research agreement with W. L. Gore & Associates, a global materials science company. On every level it seems like a natural fit.

ViaCyte has developed a way of maturing embryonic stem cells into an early form of the cells that produce insulin. They then insert those cells into a permeable device that can be implanted under the skin. Inside the device, the cells mature into insulin-producing cells. While ViaCyte has experience developing the cells, Gore has experience in the research, development and manufacturing of implantable devices.

Gore-tex-fabricWhat they hope to do is develop a kind of high-tech version of what Gore already does with its Gore-Tex fabrics. Gore-Tex keeps the rain out but allows your skin to breathe. To treat diabetes they need a device that keeps the immune system out, so it won’t attack the cells inside, but allows those cells to secrete insulin into the body.

As Edward Gunzel, Technical Leader for Gore PharmBIO Products, said in a news release, each side brings experience and expertise that complements the other:

“We have a proven track record of developing and commercializing innovative new materials and products to address challenging implantable medical device applications and solving difficult problems for biologics manufacturers.  Gore and ViaCyte began exploring a collaboration in 2016 with early encouraging progress leading to this agreement, and it was clear to us that teaming up with ViaCyte provided a synergistic opportunity for both companies.  We look forward to working with ViaCyte to develop novel implantable delivery technologies for cell therapies.”

AMD2

How macular degeneration destroys central vision

Then last week Regenerative Patch Technologies (RPT), which is running a CIRM-funded clinical trial targeting age-related macular degeneration (AMD), announced an investment from Santen Pharmaceutical, a Japanese company specializing in ophthalmology research and treatment.

The investment will help with the development of RPT’s therapy for AMD, a condition that affects millions of people around the world. It’s caused by the deterioration of the macula, the central portion of the retina which is responsible for our ability to focus, read, drive a car and see objects like faces in fine details.

RPE

RPT is using embryonic stem cells to produce the support cells, or RPE cells, needed to replace those lost in AMD. Because these cells exist in a thin sheet in the back of the eye, the company is assembling these sheets in the lab by growing the RPE cells on synthetic scaffolds. These sheets are then surgically implanted into the eye.

In a news release, RPT’s co-founder Dennis Clegg says partnerships like this are essential for small companies like RPT:

“The ability to partner with a global leader in ophthalmology like Santen is very exciting. Such a strong partnership will greatly accelerate RPT’s ability to develop our product safely and effectively.”

These partnerships are not just good news for those involved, they are encouraging for the field as a whole. When big companies like Gore and Santen are willing to invest their own money in a project it suggests growing confidence in the likelihood that this work will be successful, and that it will be profitable.

As the current blockbuster movie ‘Beauty and the Beast’ is proving; with the right partner you can not only make magic, you can also make a lot of money. For potential investors those are both wonderfully attractive qualities. We’re hoping these two new partnerships will help RPT and ViaCyte advance their research. And that these are just the first of many more to come.

Could the Answer to Treating Parkinson’s Disease Come From Within the Brain?

Sometimes a solution to a disease doesn’t come in the form of a drug or a stem cell therapy, but from within ourselves.

Yesterday, scientists from the Karolinska Institutet in Sweden reported an alternative strategy for treating Parkinson’s disease that involves reprogramming specific cells in the brain into the nerve cells killed off by the disease. Their method, which involves delivering reprogramming genes into brain cells called astrocytes, was able to alleviate motor symptoms associated with Parkinson’s disease in mice.

What is Parkinson’s Disease and how is it treated?

Parkinson’s disease (PD) is a progressive neurodegenerative disease that’s characterized by the death of dopamine-producing nerve cells (called dopaminergic neurons) in an area of the brain that controls movement.

Dopaminergic neurons grown in a culture dish. (Image courtesy of Faria Zafar, Parkinson’s Institute).

PD patients experience tremors in their hands, arms and legs, have trouble starting and stopping movement, struggle with maintaining balance and have issues with muscle stiffness. These troublesome symptoms are caused by a lack dopamine, a chemical made by dopaminergic neurons, which signals to the part of the brain that controls how a person initiates and coordinates movement.

Over 10 million people in the world are affected by PD and current therapies only treat the symptoms of the disease rather than prevent its progression. Many of these treatments involve drugs that replace the lost dopamine in the brain, but these drugs lose their effectiveness over time as the disease kills off more neurons, and they come with their own set of side effects.

Another strategy for treating Parkinson’s is replacing the lost dopaminergic neurons through cell-based therapies. However this research is still in its early stages and would require patients to undergo immunosuppressive therapy because the stem cell transplants would likely be allogeneic (from a donor) rather than autologous (from the same individual).

Drug and cell-based therapies both involve taking something outside the body and putting it in, hoping that it does the right thing and prevents the disease. But what about using what’s already inside the human body to fight off PD?

This brings us to today’s study where scientists reprogrammed brain cells in vivo (meaning inside a living organism) to produce dopamine in mice with symptoms that mimic Parkinson’s. Their method, which was published in the journal Nature Biotechnology, was successful in alleviating some of the Parkinson’s-related movement problems the mice had. This study was funded in part by a CIRM grant and received a healthy amount of coverage in the media including STATnews, San Diego Union-Tribune and Scientific American.

Reprogramming the brain to make more dopamine

Since Shinya Yamanaka published his seminal paper on reprogramming adult somatic cells into induced pluripotent stem cells, scientists have taken the building blocks of his technology a step further to reprogram one adult cell type into another. This process is called “direct reprogramming” or “transdifferentiation”. It involves delivering a specific cocktail of genes into cells that rewrite the cells identity, effectively turning them into the cell type desired.

The Karolinska team found that three genes: NEUROD1, ASCL1 and LMX1A combined with a microRNA miR218 were able to reprogram human astrocytes into induced dopaminergic neurons (iDANs) in a lab dish. These neurons looked and acted like the real thing and gave the scientists hope that this combination of factors could reprogram astrocytes into iDANs in the brain.

The next step was to test these factors in mice with Parkinson’s disease. These mice were treated with a drug that killed off their dopaminergic neurons giving them Parkinson’s-like symptoms. The team used viruses to deliver the reprogramming cocktail to astrocytes in the brain. After a few weeks, the scientists observed that some of the “infected” astrocytes developed into iDANs and these newly reprogrammed neurons functioned properly, and more importantly, helped reverse some of the motor symptoms observed in these mice.

This study offers a new potential way to treat Parkinson’s by reprogramming cells in the brain into the neurons that are lost to the disease. While this research is still in its infancy, the scientists plan to improve the safety of their technology so that it can eventually be tested in humans.

Bonus Blog Interview for World Parkinson’s Day

Ernest Arenas, Karolinska Institutet

In honor of World Parkinson’s day (April 11th), I’m providing a bonus blog interview about this research. I reached out to the senior author of this study, Dr. Ernest Arenas, to ask him a few more questions about his publication and the future studies his team is planning.

Q) What are the major findings of your current study and how do they advance research on Parkinson’s disease?

The current treatment for Parkinson’s disease (PD) is symptomatic and does not change the course of the disease. Cell replacement therapies, such as direct in vivo reprogramming of in situ [local] astrocytes into dopamine (DA) neurons, work by substituting the cells lost by disease and have the potential to halt or even reverse motor alterations in PD.

Q) Can you comment on the potential for gene therapy treatments for Parkinson’s patients?

We see direct in vivo reprogramming of brain astrocytes into dopamine neurons in situ as a possible future alternative to DA cell transplantation. This method represents a gene therapy approach to cell replacement since we use a virus to deliver four reprogramming factors. In this method, the donor cells are in the host brain and there is no need to search for donor cells and no cell transplantation or immunosuppression. The method for the moment is an experimental prototype and much more needs to be done in order to improve efficiency, safety and to translate it to humans.

Q) Will reprogrammed iDANs be susceptible to Parkinson’s disease over time?

As any other cell replacement therapy, the cells would be, in principle, susceptible to Parkinson’s disease. It has been found that PD catches up with transplanted cells in 15-20 years. We think that this is a sufficiently long therapeutic window.

In addition, direct in vivo reprogramming may also be performed with drug-inducible constructs that could be activated years after, as disease progresses. This might allow adding more cells by turning on the reprogramming factors with pharmacological treatment to the host. This was not tested in our study but the basic technology to develop such strategies currently exist.

Q) What are your plans for future studies and translating this research towards the clinic?

In our experiments, we used transgenic mice in order to test our approach and to ensure that we only reprogrammed astrocytes. There is a lot that still needs to be done in order to develop this approach as a therapy for Parkinson’s disease. This includes improving the efficiency and the safety of the method, as well as developing a strategy suitable for therapy in humans. This can be achieved by further improving the reprogramming cocktail, by using a virus with a selective tropism [affinity] for astrocytes and that do not incorporate the constructs into the DNA of the host cell, as well as using constructs with astrocyte-specific promoters and capable of self-regulating depending on the cell context.

Our study demonstrates for the first time that it is possible to use direct reprogramming of host brain cells in order to rescue neurological symptoms. These results indicate that direct reprogramming has the potential to become a novel therapeutic approach for Parkinson’s disease and opens new opportunities for the treatment of patients with neurological disorders.

How Parkinson’s disease became personal for one stem cell researcher

April is Parkinson’s disease Awareness Month. This year the date is particularly significant because 2017 is the 200th anniversary of the publication of British apothecary James Parkinson’s “An Essay on the Shaking Palsy”, which is now recognized as a seminal work in describing the disease.

Schuele_headshotTo mark the occasion we talked with Dr. Birgitt Schuele, Director Gene Discovery and Stem Cell Modeling at the Parkinson’s Institute and Clinical Center in Sunnyvale, California. Dr. Schuele recently received funding from CIRM for a project using new gene-editing technology to try and halt the progression of Parkinson’s.

 

 

What got you interested in Parkinson’s research?

People ask if I have family members with Parkinson’s because a lot of people get into this research because of a family connection, but I don’t.  I was always excited by neuroscience and how the brain works, and I did my medical residency in neurology and had a great mentor who specialized in the neurogenetics of Parkinson’s. That helped fuel my interest in this area.

I have been in this field for 15 years, and over time I have gotten to know a lot of people with Parkinson’s and they have become my friends, so now I’m trying to find answers and also a cure for Parkinson’s. For me this has become personal.

I have patients that I talk to every couple of months and I can see how their disease is progressing, and especially for people with early or young onset Parkinson’s. It’s devastating. It has a huge effect on the person and their family, and on relationships, even how they have to talk to their kids about their risk of getting the disease themselves. It’s hard to see that and the impact it has on people’s lives. And because Parkinson’s is progressive, I get to see, over the years, how it affects people, it’s very hard.

Talk about the project you are doing that CIRM is funding

It’s very exciting. The question for Parkinson’s is how do you stop disease progression, how do you stop the neurons from dying in areas affected by the disease. One protein, identified in 1997 as a genetic form of Parkinson’s, is alpha-synuclein. We know from studying families that have Parkinson’s that if you have too much alpha-synuclein you get early onset, a really aggressive form of Parkinson’s.

I followed a family that carries four copies of this alpha-synuclein gene (two copies is the normal figure) and the age of onset in this family was in their mid 30’s. Last year I went to a funeral for one of these family members who died from Parkinson’s at age 50.

We know that this protein is bad for you, if you have too much it kills brains cells. So we have an idea that if you lower levels of this protein it might be an approach to stop or shield those cells from cell death.

We are using CRISPR gene editing technology to approach this. In the Parkinson’s field this idea of down-regulation of alpha-synuclein protein isn’t new, but previous approaches worked at the protein level, trying to get rid of it by using, for example, immunotherapy. But instead of attacking the protein after it has been produced we are starting at the genomic level. We want to use CRISPR as a way to down-regulate the expression of the protein, in the same way we use a light dimmer to lower the level of light in a room.

But this is a balancing act. Too much of the protein is bad, but so is too little. We know if you get rid of the protein altogether you get negative effects, you cause complications. So we want to find the right level and that’s complex because the right level might vary from person to person.

We are starting with the most extreme levels, with people who have twice as much of this protein as is normal. Once we understand that better, then we can look at people who have levels that are still higher than normal but not at the upper levels we see in early-onset Parkinson’s. They have more subtle changes in their production or expression of this protein. It’s a little bit of a juggling act and it might be different for different patients. We start with the most severe ones and work our way to the most common ones.

One of the frustrations I often hear from patients is that this is all taking so long. Why is that?

Parkinson’s has been overall frustrating for researchers as well. Around 100 years ago, Dr. Lewy first described the protein deposits and the main neuropathology in Parkinson’s. About 20 years ago, mutations in the alpha-synuclein gene were discovered, and now we know approximately 30 genes that are associated with, or can cause Parkinson’s. But it was all very descriptive. It told us what is going on but not why.

Maybe we thought it was straight forward and maybe researchers only focused on what we knew at that point. In 1957, the neurotransmitter dopamine was identified and since the 1960s people have focused on Parkinson’s as a dopamine-deficient problem because we saw the amazing effects L-Dopa had on patients and how it could help ease their symptoms.

But I would say in the last 15 years we have looked at it more closely and realized it’s more complicated than that. There’s also a loss of sense of smell, there’s insomnia, episodes of depression, and other things that are not physical symptoms. In the last 10 years or so we have really put the pieces together and now see Parkinson’s as a multi-system disease with neuronal cell death and specific protein deposits called Lewy Bodies. These Lewy Bodies contain alpha-synuclein and you find them in the brain, the gut and the heart and these are organs people hadn’t looked at because no one made the connection that constipation or depression could be linked to the disease. It turns out that Parkinson’s is much more complicated than just a problem in one particular region of the brain.

The other reason for slow progress is that we don’t have really good models for the disease that are predictive for clinical outcomes. This is why probably many clinical trials in the neurodegenerative field have failed to date. Now we have human induced pluripotent stem cells (iPSCs) from people with Parkinson’s, and iPSC-derived neurons allow us to better model the disease in the lab, and understand its underlying mechanisms  more deeply. The technology has now advanced so that the ability to differentiate these cells into nerve cells is better, so that you now have iPSC-derived neurons in a dish that are functionally active, and that act and behave like dopamine-producing neurons in the brain. This is an important advance.

Will this lead to a clinical trial?

That’s the idea, that’s our hope.

We are working with professor Dr. Deniz Kirik at the University of Lund in Sweden. He’s an expert in the field of viral vectors that can be used in humans – it’s a joint grant between us – and so what we learn from the human iPS cultures, he’ll transfer to an animal model and use his gene vector technology to see if we can see the same effects in vivo, in mice.

We are using a very special Parkinson’s mouse model – developed at UC San Francisco – that has the complete human genomic structure of the alpha-synuclein gene. If all goes well, we hope that ultimately we could be ready in a couple of years to think about preclinical testing and then clinical trials.

What are your hopes for the future?

My hope is that I can contribute to stopping disease progression in Parkinson’s. If we can develop a drug that can get rid of accumulated protein in someone’s brain that should stop the cells from dying. If someone has early onset PD and a slight tremor and minor walking problems, stopping the disease and having a low dose of dopamine therapy to control symptoms is almost a cure.

The next step is to develop better biomarkers to identify people at risk of developing Parkinson’s, so if you know someone is a few years away from developing symptoms, and you have the tools in place, you can start treatment early and stop the disease from kicking in, even before you clinically have symptoms.

Thinking about people who have been diagnosed with a disease, who are ten years into the disease, who already have side effects from the disease, it’s a little harder to think of regenerative medicine, using embryonic or iPSCs for this. I think that it will take longer to see results with this approach, but that’s the long-term hope for the future. There are many  groups working in this space, which is critical to advance the field.

Why is Parkinson’s Awareness Month important?

It’s important because, while a lot of people know about the disease, there are also a lot of misconceptions about Parkinson’s.

Parkinson’s is confused with Alzheimer’s or dementia and cognitive problems, especially the fact that it’s more than just a gait and movement problem, that it affects many other parts of the body too.

Stem Cell Stories That Caught Our Eye: Plasticity in the pancreas and two cool stem cell tools added to the research toolbox

There’s more plasticity in the pancreas than we thought. You’re taught a lot of things about the world when you’re young. As you get older, you realize that not everything you’re told holds true and it’s your own responsibility to determine fact from fiction. This evolution in understanding happens in science too. Scientists do research that leads them to believe that biological processes happen a certain way, only to sometimes find, a few years later, that things are different or not exactly what they had originally thought.

There’s a great example of this in a study published this week in Cell Metabolism about the pancreas. Scientists from UC Davis found that the pancreas, which secretes a hormone called insulin that helps regulate the levels of sugar in your blood, has more “plasticity” than was originally believed. In this case, plasticity refers to the ability of a tissue or organ to regenerate itself by replacing lost or damaged cells.

The long-standing belief in this field was that the insulin producing cells, called beta cells, are replenished when beta cells actively divide to create more copies of themselves. In patients with type 1 diabetes, these cells are specifically targeted and killed off by the immune system. As a result, the beta cell population is dramatically reduced, and patients have to go on life-long insulin treatment.

UC Davis researchers have identified another type of insulin-producing cell in the islets, which appears to be an immature beta cell shown in red. (UC Davis)

But it turns out there is another cell type in the pancreas that is capable of making beta cells and they look like a teenage, less mature version of beta cells. The UC Davis team identified these cells in mice and in samples of human pancreas tissue. These cells hangout at the edges of structures called islets, which are clusters of beta cells within the pancreas. Upon further inspection, the scientists found that these immature beta cells can secrete insulin but cannot detect blood glucose like mature beta cells. They also found their point of origin: the immature beta cells developed from another type of pancreatic cell called the alpha cell.

Diagram of immature beta cells from Cell Metabolism.

In coverage by EurekAlert, Dr Andrew Rakeman, the director of discovery research at the Juvenile Diabetes Research Foundation, commented on the importance of this study’s findings and how it could be translated into a new approach for treating type 1 diabetes patients:

“The concept of harnessing the plasticity in the islet to regenerate beta cells has emerged as an intriguing possibility in recent years. The work from Dr. Huising and his team is showing us not only the degree of plasticity in islet cells, but the paths these cells take when changing identity. Adding to that the observations that the same processes appear to be occurring in human islets raises the possibility that these mechanistic insights may be able to be turned into therapeutic approaches for treating diabetes.”

 

Say hello to iPSCORE, new and improved tools for stem cell research. Stem cells are powerful tools to model human disease and their power got a significant boost this week from a new study published in Stem Cell Reports, led by scientists at UC San Diego School of Medicine.

The team developed a collection of over 200 induced pluripotent stem cell (iPS cell) lines derived from people of diverse ethnic backgrounds. They call this stem cell tool kit “iPSCORE”, which stands for iPSC Collection for Omic Research (omics refers to a field of study in biology ending in -omics, such as genomics or proteomics). The goal of iPSCORE is to identify particular genetic variants (unique differences in DNA sequence between people’s genomes) that are associated with specific diseases and to understand why they cause disease at the molecular level.

In an interview with Phys.org, lead scientist on the study, Dr. Kelly Frazer, further explained the power of iPSCORE:

“The iPSCORE collection contains 75 lines from people of non-European ancestry, including East Asian, South Asian, African American, Mexican American, and Multiracial. It includes multigenerational families and monozygotic twins. This collection will enable us to study how genetic variation influences traits, both at a molecular and physiological level, in appropriate human cell types, such as heart muscle cells. It will help researchers investigate not only common but also rare, and even family-specific variations.”

This research is a great example of scientists identifying a limitation in stem cell research and expanding the stem cell tool kit to model diseases in a diverse human population.

A false color scanning electron micrograph of cultured human neuron from induced pluripotent stem cell. Credit: Mark Ellisman and Thomas Deerinck, UC San Diego.

Stem cells that can grow into ANY type of tissue. Embryonic stem cells can develop into any cell type in the body, earning them the classification of pluripotent. But there is one type of tissue that embryonic stem cells can’t make and it’s called extra-embryonic tissue. This tissue forms the supportive tissue like the placenta that allows an embryo to develop into a healthy baby in the womb.

Stem cells that can develop into both extra-embryonic and embryonic tissue are called totipotent, and they are extremely hard to isolate and study in the lab because scientists lack the methods to maintain them in their totipotent state. Having the ability to study these special stem cells will allow scientists to answer questions about early embryonic development and fertility issues in women.

Reporting this week in the journal Cell, scientists from the Salk Institute in San Diego and Peking University in China identified a cocktail of chemicals that can stabilize human stem cells in a totipotent state where they can give rise to either tissue type. They called these more primitive stem cells extended pluripotent stem cells or EPS cells.

Salk Professor Juan Carlos Izpisua Bemonte, co–senior author of the paper, explained the problem their study addressed and the solution it revealed in a Salk news release:

“During embryonic development, both the fertilized egg and its initial cells are considered totipotent, as they can give rise to all embryonic and extra-embryonic lineages. However, the capture of stem cells with such developmental potential in vitro has been a major challenge in stem cell biology. This is the first study reporting the derivation of a stable stem cell type that shows totipotent-like bi-developmental potential towards both embryonic and extra-embryonic lineages.”

Human EPS cells (green) can be detected in both the embryonic part (left) and extra-embryonic parts (placenta and yolk sac, right) of a mouse embryo. (Salk Institute)

Using this new method, the scientists discovered that human EPS stem cells were able to develop chimeric embryos with mouse stem cells more easily than regular embryonic stem cells. First author on the study, Jun Wu, explained why this ability is important:

“The superior chimeric competency of both human and mouse EPS cells is advantageous in applications such as the generation of transgenic animal models and the production of replacement organs. We are now testing to see whether human EPS cells are more efficient in chimeric contribution to pigs, whose organ size and physiology are closer to humans.”

The Salk team reported on advancements in generating interspecies chimeras earlier this year. In one study, they were able to grow rat organs – including the pancreas, heart and eyes – in a mouse. In another study, they grew human tissue in early-stage pig and cattle embryos with the goal of eventually developing ways to generate transplantable organs for humans. You can read more about their research in this Salk news release.