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

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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.

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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.

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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.

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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.

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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.

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.

Growing a rat pancreas in a mouse with stem cells & CRISPR: a solution for the organ shortage crisis?

Right now, about 120,000 Americans are on a waiting list for an organ transplant and 22 will die today before any organs become available. The plain truth is there aren’t enough organ donors to meet the demand. And according to the U.S. Department of Health and Human Services, the number of available organ donors has remained static over the past decade. How can we overcome this crisis?

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The need for organ transplants is growing but the number of donors is stagnant. Image: U.S. Dept. Human Health Services

One answer may be stem cells. These “blank slate” cells can specialize into virtually any cell type in the body which has many scientists pursuing the holy grail of stem cell research: creating an unlimited supply of human organs. Today, a team of Salk Institute scientists report in Cell that they’ve taken an early but important step toward that goal by showing it’s possible to grow rat organs within a mouse. The results bode well for not only organ transplants but also for the study of human development and disease.

Chimera – monster or medical marvel?
Our regular Stem Cellar readers will be familiar with several fascinating studies using stem cell-based 3D bioprinters or bioscaffolds which aim to one day enable the manufacturing of human tissues and organs. Instead of taking this engineering approach, the Salk team seeks a strategy in which chimeric animals are bred to grow human organs. The term “chimeric” is borrowed from Greek mythology that told tales of the chimera, a monster with a lion’s heads, a goat’s body and a serpent’s tail.

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The chimera of Greek Mythology: part lion, goat and snake. Image: Wikimedia Commons

The team’s first set of experiments explored the feasibility of this method by first focusing on rat-mouse chimeras. Reprogramming skin cells collected from rat tails, the scientists generated induced pluripotent stem cells (iPSCs) – cells with the embryonic stem cell-like ability to become any cell type – and injected them into very early stage mouse embryos. The embryos were then implanted into surrogate female mice and successfully carried to term. Examination of the resulting mouse pups showed that their tissues and organs contained a patchwork of both rat and mouse cells.

And for my next trick, I will make a rat pancreas in a mouse
Now, if the ultimate goal is to grow organs that are 100% human in a host animal, an organ that merely has a random patchwork human cells would miss the mark. To show there’s a way around this problem, the Salk team used the CRISPR gene-editing technique to generate mouse embryos that lacked a gene that’s critical for the development of the pancreas. Without the gene, no pancreas forms and the mice died shortly after birth. But when the rat iPSCs were integrated into the gene edited mice embryos, the rat cells picked up the slack as the embryo developed, resulting in chimeric mice with rat pancreases.

Using the same CRISPR gene editing strategy, the researchers also grew rat hearts, and if you can believe it, rat eyes in the chimeric mice. On top of that, the mice in these experiments were healthy with most reaching adulthood and one living two years, an elderly age for mice.

A first step toward growing patient-specific human organs in large animals
One small, actually big, problem is that mice are much too little to serve as chimeric hosts for human organs. So the team repeated these mixed species experiments in pigs which are much better matched to humans. In this case, they added human iPSCs to the pig embryos, implanted them into female pigs and let the embryos develop for four weeks. Although it wasn’t as efficient as the rat-mouse chimeras, the researchers did indeed observe human cells that had incorporated into the chimera and were showing the early signs of specializing in different cell types within the implanted pig embryos.

This work is the first time human iPSCs have been incorporated into large animal species (they also got it to work with cattle) and many years of lab work remain before this approach can help solves the organ shortage crisis. But the potential applications are spellbinding. Imagine a patient in need of an organ transplant: a small skin biopsy is collected to make iPSCs and, using this chimeric animal approach, a patient-derived organ could be grown.

Juan Carlos Izpisua Belmonte, the study’s team leader, talked about this possibility and more in a press release:

“Of course, the ultimate goal of chimeric research is to learn whether we can use stem-cell and gene-editing technologies to generate genetically-matched human tissues and organs, and we are very optimistic that continued work will lead to eventual success. But in the process we are gaining a better understanding of species evolution as well as human embryogenesis and disease that is difficult to get in other ways.”

Ethical concerns
Now, if the idea of breeding pigs or cows with human organs make you a little uneasy, you aren’t alone.  In fact, the National Institutes of Health announced in 2015 that they had halted funding research that introduces human stem cells into other animals. They want more time “to evaluate the state of the science in this area, the ethical issues that should be considered, and the relevant animal welfare concerns associated with these types of studies.”  To read more discussion on this topic, read this MIT Technology Review article from a year ago.

 

Translating great stem cell ideas into effective therapies

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CIRM funds research trying to solve the Alzheimer’s puzzle

In science, there are a lot of terms that could easily mystify people without a research background; “translational” is not one of them. Translational research simply means to take findings from basic research and advance them into something that is ready to be tested in people in a clinical trial.

Yesterday our Governing Board approved $15 million in funding for four projects as part of our Translational Awards program, giving them the funding and support that we hope will ultimately result in them being tested in people.

Those projects use a variety of different approaches in tackling some very different diseases. For example, researchers at the Gladstone Institutes in San Francisco received $5.9 million to develop a new way to help the more than five million Americans battling Alzheimer’s disease. They want to generate brain cells to replace those damaged by Alzheimer’s, using induced pluripotent stem cells (iPSCs) – an adult cell that has been changed or reprogrammed so that it can then be changed into virtually any other cell in the body.

CIRM’s mission is to accelerate stem cell treatments to patients with unmet medical needs and Alzheimer’s – which has no cure and no effective long-term treatments – clearly represents an unmet medical need.

Another project approved by the Board is run by a team at Children’s Hospital Oakland Research Institute (CHORI). They got almost $4.5 million for their research helping people with sickle cell anemia, an inherited blood disorder that causes intense pain, and can result in strokes and organ damage. Sickle cell affects around 100,000 people in the US, mostly African Americans.

The CHORI team wants to use a new gene-editing tool called CRISPR-Cas9 to develop a method of editing the defective gene that causes Sickle Cell, creating a healthy, sickle-free blood supply for patients.

Right now, the only effective long-term treatment for sickle cell disease is a bone marrow transplant, but that requires a patient to have a matched donor – something that is hard to find. Even with a perfect donor the procedure can be risky, carrying with it potentially life-threatening complications. Using the patient’s own blood stem cells to create a therapy would remove those complications and even make it possible to talk about curing the disease.

While damaged cartilage isn’t life-threatening it does have huge quality of life implications for millions of people. Untreated cartilage damage can, over time lead to the degeneration of the joint, arthritis and chronic pain. Researchers at the University of Southern California (USC) were awarded $2.5 million to develop an off-the-shelf stem cell product that could be used to repair the damage.

The fourth and final award ($2.09 million) went to Ankasa Regenerative Therapeutics, which hopes to create a stem cell therapy for osteonecrosis. This is a painful, progressive disease caused by insufficient blood flow to the bones. Eventually the bones start to rot and die.

As Jonathan Thomas, Chair of the CIRM Board, said in a news release, we are hoping this is just the next step for these programs on their way to helping patients:

“These Translational Awards highlight our goal of creating a pipeline of projects, moving through different stages of research with an ultimate goal of a successful treatment. We are hopeful these projects will be able to use our newly created Stem Cell Center to speed up their progress and pave the way for approval by the FDA for a clinical trial in the next few years.”

Advancements in gene editing make blind rats see light

Gene editing is a rapidly advancing technology that scientists are using to manipulate the genomes of cells with precision and accuracy. Many of these experiments are being conducted on stem cells to genetic mutations in an attempt to find cures for various diseases like cancer, HIV and blindness.

Speaking of blindness, researchers from the Salk Institute reported today that they’ve improved upon the current CRISPR/Cas9 gene editing technology and found a more efficient way to edit the genomes of cells in living animals. They used their technology on blind rats that had a genetic disease called retinitis pigmentosa (RP) and found that the rats were able to see light following the treatment.

The really exciting part about their findings is that their CRISPR technology works well on dividing cells like stem cells and progenitor cells, which is typically how scientists use the CRISPR technology, but it also works on adult cells that do not divide – a feat that hasn’t been accomplished before.

Their results, which were published today in the journal Nature, offer a new tool that scientists can use to target cells that no longer divide in tissues and organs like the eye, brain, pancreas and heart.

According to a Salk news release:

“The new Salk technology is ten times more efficient than other methods at incorporating new DNA into cultures of dividing cells, making it a promising tool for both research and medicine. But, more importantly, the Salk technique represents the first time scientists have managed to insert a new gene into a precise DNA location in adult cells that no longer divide, such as those of the eye, brain, pancreas or heart, offering new possibilities for therapeutic applications in these cells.”

CRISPR gene edited neurons, which are non-dividing brain cells, are shown in green while cell nuclei are shown in blue. (Salk)

CRISPR gene edited neurons, which are non-dividing brain cells, are shown in green while cell nuclei are shown in blue. (Salk)

Salk Professor and senior author on the study, Juan Carlos Izpisua Belmonte, explained the big picture of their findings:

“We are very excited by the technology we discovered because it’s something that could not be done before. For the first time, we now have a technology that allows us to modify the DNA of non-dividing cells, to fix broken genes in the brain, heart and liver. It allows us for the first time to be able to dream of curing diseases that we couldn’t before, which is exciting.”

If you want to learn more about the science behind their new CRISPR gene editing technology, check out the Salk news release and coverage in Genetic Engineering & Biotechnology News. You can also watch this short three minute video about the study made by the Salk Institute.

Stem cell stories that caught our eye: healing diabetic ulcers, new spinal cord injury insights & an expanding CRISPR toolbox

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Stem cells heal diabetic foot ulcers in pilot study
Foot ulcers are one of the many long-term complications that diabetics face. About 15 percent of patients develop these open sores which typically appear at the bottom of the foot. In a quarter of these cases, the ulcers lead to serious infection requiring amputation.

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Diabetic foot ulcers are open sores that don’t heal and in many cases leads to amputation. Image source: Izunpharma

But help may be on the horizon in the form of stem cells. Researchers at Mansoura University in Egypt recently presented results of a small study in which 10 patients with diabetic foot ulcers received standard care and another 10 patients received standard care plus injections of mesenchymal stem cells that had been collected from each patient’s own bone marrow. After just six weeks, the stem cell treated group showed a 50% reduction in the foot ulcers while the group with only standard care had a mere 7% reduction.

These superior results with the stem cells were observed even though the group receiving the stem cells had larger foot ulcers to begin with compared to the untreated patients. There are many examples of mesenchymal stem cells’ healing power which make them an extremely popular cell source for hundreds of on-going clinical trials. Mesenchymal stem cells are known to reduce inflammation and increase blood vessel formation, two properties that may be at work to give diabetic foot ulcers the chance to get better.

Medscape Medical News reported on these results which were presented at the 2016 annual meeting of the European Association for the Study of Diabetes (EASD) 2016 Annual Meeting

Suppressing nerve signals to help spinal cord injury victims
Losing the use of one’s limbs is a profound life-altering change for spinal cord injury victims. But their quality of life also suffers tremendously from the loss of bladder control and chronic pain sensations. So much so, victims often say that just improving these secondary symptoms would make a huge improvement in their lives.

While current stem cell-based clinical trials, like the CIRM-funded Asterias study, aim to reverse paralysis by restoring loss nerve signals, recent CIRM-funded animal data published in Cell Stem Cell from UC San Francisco suggest that nerve cells that naturally suppress nerve signals may be helpful for these other symptoms of spinal cord injury.

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Mature inhibitory neuron derived from human embryonic stem cells is shown after successfully migrated and integrated into the injured mouse spinal cord.
Photo by Jiadong Chen, UCSF

It turns out that the bladder control loss and chronic pain may be due to overactive nerve signals. So the lab of Arnold Kriegstein transplanted inhibitory nerve cells – derived from human embryonic stem cells – into mice with spinal cord injuries. The scientists observed that these human inhibitory nerve cells, or interneurons, successfully made working connections in the damaged mouse spinal cords. The rewiring introduced by these interneurons also led to reduced pain behaviors in the mice as well as improvements in bladder control.

 

 

In a Yahoo Finance interview, Kreigstein told reporters he’s eager to push forward with these intriguing results:

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Arnold Kriegstein, UCSF

“As a clinician, I’m very aware of the urgency that’s felt among patients who are often very desperate for treatment. As a result, we’re very interested in accelerating this work toward clinical trials as soon as possible, but there are many steps along the way. We have to demonstrate that this is safe, as well as replicating it in other animals. This involves scaling up the production of these human interneurons in a way that would be compatible with a clinical product.”

 

Expanding the CRISPR toolbox
If science had a fashion week, the relatively new gene editing technology called CRISPR/Cas9 would be sure to dominate the runway. You can think of CRISPR/Cas9 as a protein and RNA complex that acts as a molecular scissor which directly targets and cuts specific sequences of DNA in the human genome. Scientists are using CRISPR/Cas9 to develop innovative biomedical techniques such as removing disease-causing mutations in stem cells in hopes of developing potential treatments for patients suffering from diseases that have no cures.

What’s particularly interesting about the CRISPR/Cas9 system is that the Cas9 protein responsible for cutting DNA is part of a family of CRISPR associated proteins (Cas) that have similar but slightly different functions. Scientists are currently expanding the CRISPR toolbox by exploring the functions of other CRISPR associated proteins for gene editing applications.

A CIRM-funded team at UC Berkeley is particularly interested in a CRISPR protein called C2c2, which is different from Cas9 in that it targets and cuts RNA rather than DNA. Led by Berkeley professor Jennifer Doudna, the team discovered that the CRISPR/C2c2 complex has not just one, but two, distinct ways that it cuts RNA. Their findings were published this week in the journal Nature.

The first way involves creation: C2c2 helps make the guide RNAs that are used to find the RNA molecules that it wants to cut. The second way involves destruction: after the CRISPR/C2c2 complex finds it’s RNAs of choice, C2c2 can then cut and destroy the RNAs.

Doudna commented on the potential applications for this newly added CRISPR tool in a Berkeley News release:

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Jennifer Doudna: Photo courtesy of iPSCell.com

“This study expands our molecular understanding of C2c2 to guide RNA processing and provides the first application of this novel RNase. C2c2 is essentially a self-arming sentinel that attacks all RNAs upon detecting its target. This activity can be harnessed as an auto-amplifying detector that may be useful as a low-cost diagnostic.”

 

Stem Cell Experts Discuss the Ethical Implications of Translating iPSCs to the Clinic

Part of The Stem Cellar blog series on 10 years of iPSCs.

This year, scientists are celebrating the 10-year anniversary of Shinya Yamanaka’s Nobel Prize winning discovery of induced pluripotent stem cells (iPSCs). These are cells that are very similar biologically to embryonic stem cells and can develop into any cell in the body. iPSCs are very useful in scientific research for disease modeling, drug screening, and for potential cell therapy applications.

However, with any therapy that involves testing in human patients, there are ethical questions that scientists, companies, and policy makers must consider. Yesterday, a panel of stem cell and bioethics experts at the Cell Symposium 10 Years of iPSCs conference in Berkeley discussed the ethical issues surrounding the translation of iPSC research from the lab bench to clinical trials in patients.

The panel included Shinya Yamanaka (Gladstone Institutes), George Daley (Harvard University), Christine Mummery (Leiden University Medical Centre), Lorenz Studer (Memorial Sloan Kettering Cancer Center), Deepak Srivastava (Gladstone Institutes), and Bioethicist Hank Greely (Stanford University).

iPSC Ethics Panel

iPSC Ethics Panel at the 10 Years of iPSCs Conference

Below is a summary of what these experts had to say about questions ranging from the ethics of patient and donor consent, genetic modification of iPSCs, designer organs, and whether patients should pay to participate in clinical trials.

How should we address patient or donor consent regarding iPSC banking?

Multiple institutes including CIRM are developing iPSC banks that store thousands of patient-derived iPSC lines, which scientists can use to study disease and develop new therapies. These important cell lines wouldn’t exist without patients who consent to donate their cells or tissue. The first question posed to the panel was how to regulate the consent process.

Christine Mummery began by emphasizing that it’s essential that companies are able to license patient-derived iPSC lines so they don’t have to go back to the patient and inconvenience them by asking for additional samples to make new cell lines.

George Daley and Hank Greely discussed different options for improving the informed consent process. Daley mentioned that the International Society for Stem Cell Research (ISSCR) recently updated their informed consent guidelines and now provide adaptable informed consent templates that can be used for obtaining many type of materials for human stem cell research.  Daley also mentioned the move towards standardizing the informed consent process through a single video shared by multiple institutions.

Greely agreed that video could be a powerful way to connect with patients by using talented “explainers” to educate patients. But both Daley and Greely cautioned that it’s essential to make sure that patients understand what they are getting involved in when they donate their tissue.

Greely rounded up the conversation by reminding the audience that patients are giving the research field invaluable information so we should consider giving back in return. While we can’t and shouldn’t promise a cure, we can give back in other ways like recognizing the contributions of specific patients or disease communities.

Greely mentioned the resolution with Henrietta Lack’s family as a good example. For more than 60 years, scientists have used a cancer cell line called HeLa cells that were derived from the cervical cancer cells of a woman named Henrietta Lacks. Henrietta never gave consent for her cells to be used and her family had no clue that pieces of Henrietta were being studied around the world until years later.

In 2013, the NIH finally rectified this issue by requiring that researchers ask for permission to access Henrietta’s genomic data and to include the Lacks family in their publication acknowledgements.

Hank Greely, Stanford University

Hank Greely, Stanford University

“The Lacks family are quite proud and pleased that their mother, grandmother and great grandmother is being remembered, that they are consulted on various things,” said Hank Greely. “They aren’t making any direct money out of it but they are taking a great deal of pride in the recognition that their family is getting. I think that returning something to patients is a nice thing, and a human thing.”

What are the ethical issues surrounding genome editing of iPSCs?

The conversation quickly focused on the ongoing CRISPR patent battle between the Broad Institute, MIT and UC Berkeley. For those unfamiliar with the technique, CRISPR is a gene editing technology that allows you to cut and paste DNA at precise locations in the genome. CRISPR has many uses in research, but in the context of iPSCs, scientists are using CRISPR to remove disease-causing mutations in patient iPSCs.

George Daley expressed his worry about a potential fallout if the CRISPR battle goes a certain way. He commented, “It’s deeply concerning when such a fundamentally enabling platform technology could be restricted for future gene editing applications.”

The CRISPR patent battle began in 2012 and millions of dollars in legal fees have been spent since then. Hank Greely said that he can’t understand why the Institutes haven’t settled this case already as the costs will only continue to rise, but that it might not matter how the case turns out in the end:

“My guess is that this isn’t ultimately going to be important because people will quickly figure out ways to invent around the CRISPR/Cas9 technology. People have already done it around the Cas9 part and there will probably be ways to do the same thing for the CRISPR part.”

 Christine Mummery finished off with a final point about the potential risk of trying to correct disease causing mutations in patient iPSCs using CRISPR technology. She noted that it’s possible the correction may not lead to an improvement because of other disease-causing genetic mutations in the cells that the patient and their family are unaware of.

 Should patients or donors be paid for their cells and tissue?

Lorenz Studer said he would support patients being paid for donating samples as long as the payment is reasonable, the consent form is clear, and patients aren’t trying to make money off of the process.

Hank Greely said the big issue is with inducement and whether you are paying enough money to convince people to do something they shouldn’t or wouldn’t want to do. He said this issue comes up mainly around reproductive egg donation but not with obtaining simpler tissue samples like skin biopsies. Egg donors are given money because it’s an invasive procedure, but also because a political decision was made to compensate egg donors. Greely predicts the same thing is unlikely to happen with other cell and tissue types.

Christine Mummery’s opinion was that if a patient’s iPSCs are used by a drug company to produce new successful drugs, the patient should receive some form of compensation. But she said it’s hard to know how much to pay patients, and this question was left unanswered by the panel.

Should patients pay to participate in clinical trials?

George Daley said it’s hard to justify charging patients to participate in a Phase 1 clinical trial where the focus is on testing the safety of a therapy without any guarantee that there will be beneficial outcome to the patient. In this case, charging a patient money could raise their expectations and mislead them into thinking they will benefit from the treatment. It would also be unfair because only patients who can afford to pay would have access to trials. Ultimately, he concluded that making patients pay for an early stage trial would corrupt the informed consent process. However, he did say that there are certain, rare contexts that would be highly regulated where patients could pay to participate in trials in an ethical way.

Lorenz Studer said the issue is very challenging. He knows of patients who want to pay to be in trials for treatments they hope will work, but he also doesn’t think that patients should have to pay to be in early stage trials where their participation helps the progress of the therapy. He said the focus should be on enrolling the right patient groups in clinical trials and making sure patients are properly educated about the trial they are participating.

Thoughts on the ethics behind making designer organs from iPSCs?

Deepak Srivastava said that he thinks about this question all the time in reference to the heart:

Deepak Srivastava, Gladstone Institutes

Deepak Srivastava, Gladstone Institutes

“The heart is basically a pump. When we traditionally thought about whether we could make a human heart, we asked if we could make the same thing with the same shape and design. But in fact, that’s not necessarily the best design – it’s what evolution gave us. What we really need is a pump that’s electrically active. I think going forward, we should remove the constraint of the current design and just think about what would be the best functional structure to do it. But it is definitely messing with nature and what evolution has given us.”

Deepak also said that because every organ is different, different strategies should be used. In the case of the heart, it might be beneficial to convert existing heart tissue into beating heart cells using drugs rather than transplant iPSC-derived heart cells or tissue. For other organs like the pancreas, it is beneficial to transplant stem cell-derived cells. For diabetes, scientists have shown that injecting insulin secreting cells in multiple areas of the body is beneficial to Diabetes patients.

Hank Greely concluded that the big ethical issue of creating stem cell-derived organs is safety. “Biology isn’t the same as design,” Greely said. “It’s really, really complicated. When you put something into a biological organism, the chances that something odd will happen are extremely high. We have to be very careful to avoid making matters worse.”

For more on the 10 years of iPSCs conference, check out the #CSStemCell16 hashtag on twitter.

Here’s a new gene editing strategy to treat genetic blood disorders

If you’re taking a road trip across the country, you have a starting point and an ending point. How you go from point A to point B could be one of a million different routes, but the ultimate outcome is the same: reaching your final destination.

Yesterday scientists from St. Jude Children’s Research Hospital published exciting findings in the journal Nature Medicine on a new gene editing strategy that could offer a different route for treating genetic blood disorders such as sickle cell disease (SCD) and b-thalassemia.

The scientists used a gene editing tool called CRISPR. Unless you’ve been living under a rock, you’ve heard about CRISPR in the general media as the next, hot technology that could possibly help bring cures for serious diseases.

In simple terms, CRISPR acts as molecular scissors that facilitate cutting and pasting of DNA sequences at specific locations in the genome. For blood diseases like SCD and b-thalassemia, in which blood cells have abnormal hemoglobin, CRISPR gene editing offers ways to turn on and off genes that cause the clinical symptoms of these diseases.

Fetal vs. Adult hemoglobin

Before I get into the meat of this story, let’s take a moment to discuss hemoglobin. What is it? It’s a protein found in red blood cells that transports oxygen from the lungs to the rest of the body. Hemoglobin is made up of different subunits and the composition of these hemoglobin subunits change as newborns develop into adults.

0a448-sicklecellimage

Healthy red blood cell (left), sickle cell (right).

Fetal hemoglobin (HbF) is comprised of a and g subunits while adult hemoglobin (HbA) is typically comprised of a and b subunits. Patients with SCD and b-thalassemia typically have mutations in the b globin gene. In SCD, this causes blood cells to take on an unhealthy, sickle cell shape that can clog vessels and eventually cause premature death. In b-thalassemia, the b-globin gene isn’t synthesized into protein at the proper levels and patients suffer from anemia (low red blood cell count).

One way that scientists are attempting to combat the negative side effects of mutant HbF is to tip the scales towards maintaining expression of the fetal g-globin gene. The idea spawned from individuals with hereditary persistence of fetal hemoglobin (HPFH), a condition where the hemoglobin composition fails to transition from HbF to HbA, leaving high levels of HbF in adult blood. Individuals who have HPFH and are predisposed to SCD or b-thalassemia amazingly don’t have clinical symptoms, suggesting that HbF plays either a protective or therapeutic role.

The current study is taking advantage of this knowledge in their attempt to treat blood disorders. Mitchell Weiss, senior author on the study and chair of the St. Jude Department of Hematology, explained the thought process behind their study:

“It has been known for some time that individuals with genetic mutations that persistently elevate fetal hemoglobin are resistant to the symptoms of sickle cell disease and beta-thalassemia, genetic forms of severe anemia that are common in many regions of the world. We have found a way to use CRISPR gene editing to produce similar benefits.”

CRISPRing blood stem cells for therapeutic purposes

Weiss and colleagues engineered red blood cells to have elevated levels of HbF in hopes of preventing symptoms of SCD. They used CRISPR to create a small deletion in a sequence of DNA, called a promoter, that controls expression of the hemoglobin g subunit 1 (HBG1) gene. The deletion elevates the levels of HbF in blood cells and closely mimics genetic mutations found in HPFH patients.

Weiss further explained the genome editing process in a news release:

Mitchell Weiss

Mitchell Weiss

“Our work has identified a potential DNA target for genome editing-mediated therapy and offers proof-of-principle for a possible approach to treat sickle cell and beta-thalassemia. We have been able to snip that DNA target using CRISPR, remove a short segment in a “control section” of DNA that stimulates gamma-to-beta switching, and join the ends back up to produce sustained elevation of fetal hemoglobin levels in adult red blood cells.”

The scientists genetically modified hematopoietic stem cells and blood progenitor cells from healthy individuals to make sure that their CRISPR gene editing technique was successful. After modifying the stem cells, they matured them into red blood cells in the lab and observed that the levels of HbF increased from 5% to 20%.

Encouraged by these results, they tested the therapeutic potential of their CRISPR strategy on hematopoietic stem cells from three SCD patients. While 25% of unmodified SCD blood stem cells developed red blood cells with a sickle cell shape under low-oxygen conditions (to induce stress), CRISPR edited SCD stem cells generated way fewer sickle cells (~4%) and had a higher level of HbF expression.

Many routes, one destination

The authors concluded that their genome editing technique is successful at switching hemoglobin expression from the adult form back to the fetal form. With further studies and safety testing, this strategy could be one day be developed into a treatment for patients with SCD and b-thalassemia

But the authors were also humble in their findings and admitted that there are many different genome editing strategies or routes for developing therapies for inherited blood diseases.

“Our results represent an additional approach to these existing innovative strategies and compare favorably in terms of the levels of fetal hemoglobin that are produced by our experimental system.”

My personal opinion is the more strategies thrown into the pipeline the better. As things go in science, many of these strategies won’t be successful in reaching the final destination of curing one of these diseases, but with more shots on goal, our chances of developing a treatment that works there are a lot higher.


Related links:

Stem cell stories that caught our eye: turning on T cells; fixing our brains; progress and trends in stem cells; and one young man’s journey to recover from a devastating injury

Healthy_Human_T_Cell

A healthy T cell

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Directing the creation of T cells. To paraphrase the GOP Presidential nominee, any sane person LOVES, LOVES LOVES their T cells, in a HUGE way, so HUGE. They scamper around the body getting rid of viruses and the tiny cancers we all have in us all the time. A CIRM-funded team at CalTech has worked out the steps our genetic machinery must take to make more of them, a first step in letting physicians turn up the action of our immune systems.

We have known for some time the identity of the genetic switch that is the last, critical step in turning blood stem cells into T cells, but nothing in our body is as simple as a single on-off event. The Caltech team isolated four genetic factors in the path leading to that main switch and, somewhat unsuspected, they found out those four steps had to be activated sequentially, not all at the same time. They discovered the path by engineering mouse cells so that the main T cell switch, Bcl11b, glows under a microscope when it is turned on.

“We identify the contributions of four regulators of Bcl11b, which are all needed for its activation but carry out surprisingly different functions in enabling the gene to be turned on,” said Ellen Rothenberg, the senior author in a university press release picked up by Innovations Report. “It’s interesting–the gene still needs the full quorum of transcription factors, but we now find that it also needs them to work in the right order.”

Video primer on stem cells in the brain.  In conjunction with an article in its August issue, Scientific American posted a video from the Brain Forum in Switzerland of Elena Cattaneo of the University of Milan explaining the basics of adult versus pluripotent stem cells, and in particular how we are thinking about using them to repair diseases in the brain.

The 20-minute talk gives a brief review of pioneers who “stood alone in unmarked territory.” She asks how can stem cells be so powerful; and answers by saying they have lots of secrets and those secrets are what stem cell scientist like her are working to unravel.  She notes stem cells have never seen a brain, but if you show them a few factors they can become specialized nerves. After discussing collaborations in Europe to grow replacement dopamine neurons for Parkinson’s disease, she went on to describe her own effort to do the same thing in Huntington’s disease, but in this case create the striatal nerves lost in that disease.

The video closes with a discussion of how basic stem cell research can answer evolutionary questions, in particular how genetic changes allowed higher organisms to develop more complex nervous systems.

kelley and kent

CIRM Science Officers Kelly Shepard and Kent Fitzgerald

A stem cell review that hits close to home.  IEEE Pulse, a publication for scientists who mix engineering and medicine and biology, had one of their reporters interview two of our colleagues on CIRM’s science team. They asked senior science officers Kelly Shepard and Kent Fitzgerald to reflect on how the stem cell field has progressed based on their experience working to attract top researchers to apply for our grants and watching our panel of outside reviewers select the top 20 to 30 percent of each set of applicants.

One of the biggest changes has been a move from animal stem cell models to work with human stem cells, and because of CIRM’s dedicated and sustained funding through the voter initiative Proposition 71, California scientists have led the way in this change. Kelly described examples of how mouse and human systems are different and having data on human cells has been critical to moving toward therapies.

Kelly and Kent address several technology trends. They note how quickly stem cell scientists have wrapped their arms around the new trendy gene editing technology CRISPR and discuss ways it is being used in the field. They also discuss the important role of our recently developed ability to perform single cell analysis and other technologies like using vessels called exosomes that carry some of the same factors as stem cells without having to go through all the issues around transplanting whole cells.

“We’re really looking to move things from discovery to the clinic. CIRM has laid the foundation by establishing a good understanding of mechanistic biology and how stem cells work and is now taking the knowledge and applying it for the benefit of patients,” Kent said toward the end of the interview.

jake and family

Jake Javier and his family

Jake’s story: one young man’s journey to and through a stem cell transplant; As a former TV writer and producer I tend to be quite critical about the way TV news typically covers medical stories. But a recent story on KTVU, the Fox News affiliate here in the San Francisco Bay Area, showed how these stories can be done in a way that balances hope, and accuracy.

Reporter Julie Haener followed the story of Jake Javier – we have blogged about Jake before – a young man who broke his spine and was then given a stem cell transplant as part of the Asterias Biotherapeutics clinical trial that CIRM is funding.

It’s a touching story that highlights the difficulty treating these injuries, but also the hope that stem cell therapies holds out for people like Jake, and of course for his family too.

If you want to see how a TV story can be done well, this is a great example.

The Spanish Inquisition and a tale of two stem cell agencies

Monty

Monty Python’s Spanish Inquisition sketch: Photo courtesy Daily Mail UK

It’s not often an article on stem cell research brings the old, but still much loved, British comedy series Monty Python into the discussion but a new study in the journal Cell Stem Cell does just that, comparing the impact of CIRM and the UK’s Regenerative Medicine Platform (UKRMP).

The article, written by Fiona Watt of King’s College London and Stanford’s Irv Weissman (a CIRM grantee – you can see his impressive research record here) looks at CIRM and UKRMP’s success in translating stem cell research into clinical applications in people.

It begins by saying that in research, as in real estate, location is key:

“One thing that is heavily influenced by location, however, is our source of funding. This in turn depends on the political climate of the country in which we work, as exemplified by research on stem cells.”

And, as Weissman and Watt note, political climate can have a big impact on that funding. CIRM was created by the voters of California in 2004, largely in response to President George W. Bush’s restrictions on the use of federal funds for embryonic stem cell research. UKRMP, in contrast was created by the UK government in 2013 and designed to help strengthen the UK’s translational research sector. CIRM was given $3 billion to do its work. UKRMP has approximately $38 million.

Inevitably the two agencies took very different approaches to funding, shaped in part by the circumstances of their birth – one as a largely independent state agency, the other created as a tool of national government.

CIRM, by virtue of its much larger funding was able to create world-class research facilities, attract top scientists to California and train a whole new generation of scientists. It has also been able to help some of the most promising projects get into clinical trials. UKRMP has used its more limited funding to create research hubs, focusing on areas such as cell behavior, differentiation and manufacturing, and safety and effectiveness. Those hubs are encouraged to work collaboratively, sharing their expertise and best practices.

Weissman and Watt touch on the problems both agencies ran into, including the difficulty of moving even the best research out of the lab and into clinical trials:

“Although CIRM has moved over 20 projects into clinical trials most are a long way from becoming standard therapies. This is not unexpected, as the interval between discovery and FDA approved therapeutic via clinical trials is in excess of 10 years minimum.”

 

And here is where Monty Python enters the picture. The authors quote one of the most famous lines from the series: “Nobody expects the Spanish Inquisition – because our chief weapon is surprise.”

They use that to highlight the surprises and uncertainty that stem cell research has gone through in the more than ten years since CIRM was created. They point out that a whole category of cells, induced pluripotent stem (iPS) cells, didn’t exist until 2006; and that few would have predicted the use of gene/stem cell therapy combinations. The recent development of the CRISPR/Cas9 gene-editing technology shows the field is progressing at a rate and in directions that are hard to predict; a reminder that that researchers and funding agencies should continue to expect the unexpected.

With two such different agencies the authors wisely resist the temptation to make any direct comparisons as to their success but instead conclude:

“…both CIRM and UKRMP have similar goals but different routes (and funding) to achieving them. Connecting people to work together to move regenerative medicine into the clinic is an over-arching objective and one that, we hope, will benefit patients regardless of where they live.”