Scientists fix heart disease mutation in human embryos using CRISPR

Last week the scientific community was buzzing with the news that US scientists had genetically modified human embryos using CRISPR gene editing technology. While the story broke before the research was published, many journalists and news outlets weighed in on the study’s findings and the ethical implications they raise. We covered this initial burst of news in last week’s stem cell stories that caught our eye.

Shoukhrat Mitalipov (Leah Nash, New York Times)

After a week of suspense, the highly-anticipated study was published yesterday in the journal Nature. The work was led by senior author Dr. Shoukhrat Mitalipov from Oregon Health and Sciences University (and a member of CIRM’s Grants Working Group, the panel of experts who review applications to us for funding) in collaboration with scientists from the Salk Institute and Korea’s Institute for Basic Science.

In brief, the study revealed that the teams’ CRISPR technology could correct a genetic mutation that causes a disease called hypertrophic cardiomyopathy (HCM) in 72% of human embryos without causing off-target effects, which are unwanted genome modifications caused by CRISPR. These findings are a big improvement over previous studies by other groups that had issues with off-target effects and mosaicism, where CRISPR only correctly modifies mutations in some but not all cells in an embryo.

Newly fertilized eggs before gene editing, left, and embryos after gene editing and a few rounds of cell division. (Image from Shoukrat Mitalipov in New York Times)

Mitalipov spoke to STATnews about a particularly interesting discovery that he and the other scientists made in the Nature study,

“The main finding is that the CRISPR’d embryos did not accept the “repair DNA” that the scientists expected them to use as a replacement for the mutated gene deleted by CRISPR, which the embryos inherited from their father. Instead, the embryos used the mother’s version of the gene, called the homologue.”

Sharon Begley, the author of the STATnews article, argued that this discovery means that “designer babies” aren’t just around the corner.

“If embryos resist taking up synthetic DNA after CRISPR has deleted an unwanted gene, then “designer babies,” created by inserting a gene for a desirable trait into an embryo, will likely be more difficult than expected.”

Ed Yong from the Atlantic also took a similar stance towards Mitalipov’s study in his article titled “The Designer Baby Era is Not Upon Us”. He wrote,

“The bigger worry is that gene-editing could be used to make people stronger, smarter, or taller, paving the way for a new eugenics, and widening the already substantial gaps between the wealthy and poor. But many geneticists believe that such a future is fundamentally unlikely because complex traits like height and intelligence are the work of hundreds or thousands of genes, each of which have a tiny effect. The prospect of editing them all is implausible. And since genes are so thoroughly interconnected, it may be impossible to edit one particular trait without also affecting many others.”

Dr. Juan Carlos Izpisua Belmonte, who’s a corresponding author on the paper and a former CIRM grantee from the Salk Institute, commented on the impact that this research could have on human health in a Salk news release.

Co-authors Juan Carlos Izpisua Belmonte and Jun Wu. (Salk Institute)

“Thanks to advances in stem cell technologies and gene editing, we are finally starting to address disease-causing mutations that impact potentially millions of people. Gene editing is still in its infancy so even though this preliminary effort was found to be safe and effective, it is crucial that we continue to proceed with the utmost caution, paying the highest attention to ethical considerations.”

Pam Belluck from The New York Times also suggested that this research could have a significant impact on how we prevent disease in newborns.

“This research marks a major milestone and, while a long way from clinical use, it raises the prospect that gene editing may one day protect babies from a variety of hereditary conditions.”

So when will the dawn of CRISPR babies arrive? Ed Yong took a stab at answering this million dollar question with help from experts in the field.

“Not for a while. The technique would need to be refined, tested on non-human primates, and shown to be safe. “The safety studies would likely take 10 to 15 years before FDA or other regulators would even consider allowing clinical trials,” wrote bioethicist Hank Greely in a piece for Scientific American. “The Mitalipov research could mean that moment is 9 years and 10 months away instead of 10 years, but it is not close.” In the meantime, Mitalipov’s colleague Sanjiv Kaul says, “We’ll get the method to perfection so that when it’s possible to use it in a clinical trial, we can.”

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Stem Cell Stories that Caught our Eye: CRISPRing Human Embryos, brain stem cells slow aging & BrainStorm ALS trial joins CIRM Alpha Clinics

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

Scientists claim first CRISPR editing of human embryos in the US.

Here’s the big story this week. Scientists from Portland, Oregon claim they genetically modified human embryos using the CRISPR/Cas9 gene editing technology. While their results have yet to be published in a peer review journal (though the team say they are going to be published in a prominent journal next month), if they prove true, the study will be the first successful attempt to modify human embryos in the US.

A representation of an embryo being fertilized. Scientists can inject CRISPR during fertilization to correct genetic disorders. (Getty Images).

Steve Connor from MIT Technology Review broke the story earlier this week noting that the only reports of human embryo modification were published by Chinese scientists. The China studies revealed troubling findings. CRISPR caused “off-target” effects, a situation where the CRISPR machinery randomly introduces genetic errors in a cell’s DNA, in the embryos. It also caused mosaicism, a condition where the desired DNA sequences aren’t genetically corrected in all the cells of an embryo producing an individual with cells that have different genomes. Putting aside the ethical conundrum of modifying human embryos, these studies suggested that current gene editing technologies weren’t accurate enough to safely modify human embryos.

But a new chapter in human embryo modification is beginning. Shoukhrat Mitalipov (who is a member of CIRM’s Grants Working Group, the panel of scientific experts that reviews our funding applications) and his team from the Oregon Health and Science University said that they have developed a method to successfully modify donated human embryos that avoids the problems experienced by the Chinese scientists. The team found that introducing CRISPR at the same time an embryo was being fertilized led to successful correction of disease-causing mutations while avoiding mosaicism and “off-target” effects. They grew these embryos for a few days to confirm that the genetic modifications had worked before destroying them.

The MIT piece quoted a scientist who knows of Mitalipov’s work,

“It is proof of principle that it can work. They significantly reduced mosaicism. I don’t think it’s the start of clinical trials yet, but it does take it further than anyone has before.”

Does this discovery, if it’s true, open the door further for the creation of designer babies? For discussions about the future scientific and ethical implications of this research, I recommend reading Paul Knoepfler’s blog, this piece by Megan Molteni in Wired Magazine and Jessica Berg’s article in The Conversation.

Brain stem cells slow aging in mice

The quest for eternal youth might be one step closer thanks to a new study published this week in the journal Nature. Scientists from the Albert Einstein College of Medicine in New York discovered that stem cells found in an area of the brain called the hypothalamus can slow the aging process in mice.

The hypothalamus is located smack in the center of your brain near the brain stem. It’s responsible for essential metabolic functions such as making and secreting hormones, managing body temperature and controlling feelings of hunger and thirst. Because the body’s metabolic functions decline with age, scientists have suspected that the hypothalamus plays a role in aging.

The mouse hypothalamus. (NIH, Wikimedia).

In the current study, the team found that stem cells in the hypothalamus gradually disappear as mice age. They were curious whether the disappearance of these stem cells could jump start the aging process. When they removed these stem cells, the mice showed more advanced mental and physical signs of aging compared to untreated mice.

They also conducted the opposite experiment where they transplanted hypothalamic stem cells taken from baby mice (the idea being that these stem cells would exhibit more “youthful” qualities) into the brains of middle-aged mice and saw improvements in mental and physical functions and a 10% increase in lifespan.

So what is it about these specific stem cells that slows down aging? Do they replenish the aging brain with new healthy cells or do they secrete factors that keep the brain healthy? Interestingly, the scientists found that these stem cells secreted vesicles that contained microRNAs, which are molecules that regulate gene expression by turning genes on or off.

They injected these microRNAs into the brains of middle-aged mice and found that they reversed symptoms of aging including cognitive decline and muscle degeneration. Furthermore, when they removed hypothalamic stem cells from middle-aged mice and treated them with the microRNAs, they saw the same anti-aging effects.

In an interview with Nature News, senior author on the study, Dongsheng Cai, commented that hypothalamic stem cells could have multiple ways of regulating aging and that microRNAs are just one of their tools. For this research to translate into an anti-aging therapy, “Cai suspects that anti-ageing therapies targeting the hypothalamus would need to be administered in middle age, before a person’s muscles and metabolism have degenerated beyond a point that could be reversed.”

This study and its “Fountain of Youth” implications has received ample attention from the media. You can read more coverage from The Scientist, GenBio, and the original Albert Einstein press release.

BrainStorm ALS trial joins the CIRM Alpha Clinics

Last month, the CIRM Board approved $15.9 million in funding for BrainStorm Cell Therapeutic’s Phase 3 trial that’s testing a stem cell therapy to treat patients with a devastating neurodegenerative disease called amyotrophic lateral sclerosis or ALS (also known as Lou Gehrig’s disease).

The stem cell therapy, called NurOwn®, is made of mesenchymal stem cells extracted from a patient’s bone marrow. The stem cells are genetically modified to secrete neurotrophic factors that keep neurons in the brain healthy and prevent their destruction by diseases like ALS.

BrainStorm has tested NurOwn in early stage clinical trials in Israel and in a Phase 2 study in the US. These trials revealed that the treatment was “safe and well tolerated” and that “NurOwn also achieved multiple secondary efficacy endpoints, showing clear evidence of a clinically meaningful benefit.  Notably, response rates were higher for NurOwn-treated subjects compared to placebo at all time points in the study out to 24 weeks.”

This week, BrainStorm announced that it will launch its Phase 3 CIRM-funded trial at the UC Irvine (UCI) CIRM Alpha Stem Cell Clinic. The Alpha Clinics are a network of top medical centers in California that specialize in delivering high quality stem cell clinical trials to patients. UCI is one of four medical centers including UCLA, City of Hope, and UCSD, that make up three Alpha Clinics currently supporting 38 stem cell trials in the state.

Along with UCI, BrainStorm’s Phase 3 trial will also be conducted at two other sites in the US: Mass General Hospital in Boston and California Pacific Medical Center in San Francisco. Chaim Lebovits, President and CEO, commented,

“We are privileged to have UCI and Dr. Namita Goyal join our pivotal Phase 3 study of NurOwn. Adding UCI as an enrolling center with Dr. Goyal as Principal Investigator will make the treatment more accessible to patients in California, and we welcome the opportunity to work with this prestigious institution.”

Before the Phase 3 trial can launch at UCI, it needs to be approved by our federal regulatory agency, the Food and Drug Administration (FDA), and an Institutional Review Board (IRB), which is an independent ethics committee that reviews biomedical research on human subjects. Both these steps are required to ensure that a therapy is safe to test in patients.

With promising data from their Phase 1 and 2 trials, BrainStorm’s Phase 3 trial will likely get the green light to move forward. Dr. Goyal, who will lead the trial at the UCI Alpha Clinic, concluded:

“NurOwn is a very promising treatment with compelling Phase 2 data in patients with ALS; we look forward to further advancing it in clinical development and confirming the therapeutic benefit with Brainstorm.”

Bridging the divide: stem cell students helping families with rare diseases become partners in research

Bridges & Rare Science

CIRM’s Bridges students and Rare Science’s families with rare diseases

Sometimes it’s the simplest things that make the biggest impact. For example, introducing a scientist to a patient can help them drive stem cell research forward faster than either one could do on their own.

Want proof? This year, students in CIRM’s Bridges to Stem Cell Research and Therapy program at California State University (CSU) San Marcos teamed up with parents of children with rare diseases, and the partnerships had a profound impact on all of them, one we hope might produce some long-term benefits.

Christina Waters, who helped create the partnerships, calls it “science with love.”

“We wanted to change the conversation and have researchers and families communicate, making families equal stakeholders in the research. The students bonded with the families and I truly feel that we made a difference in the lives of future researchers, in knowing how much their work can make a life changing impact on the lives of patients’ families who now have hope.”

The CIRM Bridges program helps prepare California’s undergraduate and master’s graduate students for highly productive careers in stem cell research. Students get a paid internship where they get hands-on training and education in stem cell research. They also work with patients and take part in outreach activities so they get an understanding of research that extends beyond the lab.

That’s where Christina Waters comes in. Christina is the founder of Rare Science, a non-profit group focused on rare diseases in children – we blogged about her work here – and she teamed up with CSU San Marcos to partner their Bridges students with five patient families with different rare diseases.

Cutting edge science

One of those families was Aaron Harding’s. Aaron’s son Jaxon has SYNGAP, a genetic disorder that can cause seizures, mental retardation, speech problems and autistic-like behavior. Two of the Bridges students who were doing their internship at ThermoFisher Scientific, Uju Nwizu and Emily Asbury, were given the task of using the gene-editing tool CRISPR Cas9 to help develop a deeper understanding of SYNGAP.

The students say it was an amazing experience:

Uju: “It had a huge impact on me. Every time I thought about SYNGAP I saw Jaxon’s face. This motivated me a lot.”

Emily: “People who work in labs everyday are most often working out the minutiae of research. They don’t often get a chance to see how their research can change or save the lives of real people. Meeting patients is so motivating because afterwards you aren’t just studying a mechanism, you now have a friend with the disease, so you can’t help but be personally invested in the search for a treatment.”

Emily and Uju are working to create iPSCs (induced pluripotent stem cells) that have the SYNGAP mutation. They hope these can be used to study the disease in greater depth and, maybe one day, lead to treatments for some of the symptoms.

Aaron says for families like his, knowing there are scientists working on his child’s disorder is a source of comfort, and hope:

“Personalizing diseases by connecting scientists with those they seek to impact is so important. Emily and Uju took this opportunity and ran with it, and that says a lot about them, and the team at ThermoFisher, taking on an exploring the unknown. That attitude is the heart of a scientist.”

Hearing stories like this is very gratifying, not just for the students and families involved, but for everyone here at CIRM. When we created the Bridges program our goal was to help students get the skills and experience needed to pursue a career in science. Thanks to the people at CSU San Marcos and Rare Science these students got a whole lot more.

Christina Waters: “We learned, we shared hope, we celebrated the courage of our families and the commitment of the students. It takes a village, and it is all of us working together that will make great changes for kids with rare diseases.”

For Uju and Emily, their experience in the Bridges program has made them doubly certain they want to pursue a career in science.

Uju: “I love stem cells and the promise they hold. After this program I hope to be part of a team that is committed to accelerating new stem cell therapies for rare and chronic diseases.”

Emily: “I’ve learned that I love research. After I finish my bachelor’s degree at CSU San Marcos I plan to pursue a graduate degree in molecular or cellular biology.”

 

Stem cell stories that caught our eye: spinal cord injury trial keeps pace; SMART cells make cartilage and drugs

CIRM-funded spinal cord injury trial keeping a steady pace

Taking an idea for a stem cell treatment and developing it into a Food and Drug Administration-approved cell therapy is like running the Boston Marathon because it requires incremental progress rather than a quick sprint. Asterias Biotherapeutics continues to keep a steady pace and to hit the proper milestones in its race to develop a stem cell-based treatment for acute spinal cord injury.


Just this week in fact, the company announced an important safety milestone for its CIRM-funded SciStar clinical trial. This trial is testing the safety and effectiveness of AST-OPC1, a human embryonic stem cell-derived cell therapy that aims to regenerate some of the lost movement and feeling resulting from spinal cord injuries to the neck.

Periodically, an independent safety review board called the Data Monitoring Committee (DMC) reviews the clinical trial data to make sure the treatment is safe in patients. That’s exactly what the DMC concluded as its latest review. They recommended that treatments with 10 and 20 million cell doses should continue as planned with newly enrolled clinical trial participants.

About a month ago, Asterias reported that six of the six participants who had received a 10 million cell dose – which is transplanted directly into the spinal cord at the site of injury – have shown improvement in arm, hand and finger function nine months after the treatment. These outcomes are better than what would be expected by spontaneous recovery often observed in patients without stem cell treatment. So, we’re hopeful for further good news later this year when Asterias expects to provide more safety and efficacy data on participants given the 10 million cell dose as well as the 20 million cell dose.

It’s a two-fer: SMART cells that make cartilage and release anti-inflammation drug
“It’s a floor wax!”….“No, it’s a dessert topping!”
“Hey, hey calm down you two. New Shimmer is a floor wax and a dessert topping!”

Those are a few lines from the classic Saturday Night Live skit that I was reminded of when reading about research published yesterday in Stem Cell Reports. The clever study generated stem cells that not only specialize into cartilage tissue that could help repair arthritic joints but the cells also act as a drug dispenser that triggers the release of a protein that dampens inflammation.

Using CRISPR technology, a team of researchers led by Farshid Guilak, PhD, at Washington University School of Medicine in St. Louis, rewired stem cells’ genetic circuits to produce an anti-inflammatory arthritis drug when the cells encounter inflammation. The technique eventually could act as a vaccine for arthritis and other chronic conditions. Image: ELLA MARUSHCHENKO

The cells were devised by a research team at Washington University School of Medicine in St. Louis. They started out with skin cells collected from the tails of mice. Using the induced pluripotent stem cell technique, the skin cells were reprogrammed into an embryonic stem cell-like state. Then came the ingenious steps. The team used the CRISPR gene-editing method to create a negative feedback loop in the cells’ inflammation response. They removed a gene that is activated by the potent inflammatory protein, TNF-alpha and replaced it with a gene that blocks TNF-alpha. Analogous experiments were carried out with another protein called IL-1.

Rheumatoid arthritis often affects the small joints causing painful swelling and disfigurement. Image: Wikipedia

Now, TNF-alpha plays a key role in triggering inflammation in arthritic joints. But this engineered cell, in the presence of TNF-alpha, activates the production of a protein that inhibits the actions of TNF-alpha. Then the team converted these stem cells into cartilage tissue and they went on to show that the cartilage was indeed resistant to inflammation. Pretty smart, huh? In fact, the researchers called them SMART cells for “Stem cells Modified for Autonomous Regenerative Therapy.” First author Dr. Jonathan Brunger summed up the approach succinctly in a press release:

“We hijacked an inflammatory pathway to create cells that produced a protective drug.”

This type of targeted treatment of arthritis would have a huge advantage over current anti-TNF-alpha therapies. Arthritis drugs like Enbrel, Humira and Remicade are very effective but they block the immune response throughout the body which carries an increased risk for serious infections and even cancer.

The team is now testing the cells in animal models of rheumatoid arthritis as well as other inflammation disorders. Those results will be important to determine whether or not this approach can work in a living animal. But senior Dr. Farshid Guilak also has an eye on future applications of SMART cells:

“We believe this strategy also may work for other systems that depend on a feedback loop. In diabetes, for example, it’s possible we could make stem cells that would sense glucose and turn on insulin in response. We are using pluripotent stem cells, so we can make them into any cell type, and with CRISPR, we can remove or insert genes that have the potential to treat many types of disorders.”

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 (Todd Dubnicoff)

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.

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.”