Stem Cell Stories that Caught our Eye: stem cell insights into anorexia, Zika infection and bubble baby disease

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 cell model identifies new culprit for anorexia.

Eating disorders like anorexia nervosa are often thought to be caused by psychological disturbances or societal pressure. However, research into the genes of anorexia patients suggests that what’s written in your DNA can be associated with an increased vulnerability to having this disorder. But identifying individual genes at fault for a disease this complex has remained mostly out of scientists’ reach, until now.

A CIRM-funded team from the UC San Diego (UCSD) School of Medicine reported this week that they’ve developed a stem cell-based model of anorexia and used it to identify a gene called TACR1, which they believe is associated with an increased likelihood of getting anorexia.

They took skin samples from female patients with anorexia and reprogrammed them into induced pluripotent stem cells (iPSCs). These stem cells contained the genetic information potentially responsible for causing their anorexia. The team matured these iPSCs into brain cells, called neurons, in a dish, and then studied what genes got activated. When they looked at the genes activated by anorexia neurons, they found that TACR1, a gene associated with psychiatric disorders, was switched on higher in anorexia neurons than in healthy neurons. These findings suggest that the TACR1 gene could be an identifier for this disease and a potential target for developing new treatments.

In a UCSD press release, Professor and author on the study, Alysson Muotri, said that they will follow up on their findings by studying stem cell lines derived from a larger group of patients.

Alysson Muotri UC San Diego

“But more to the point, this work helps make that possible. It’s a novel technological advance in the field of eating disorders, which impacts millions of people. These findings transform our ability to study how genetic variations alter brain molecular pathways and cellular networks to change risk of anorexia nervosa — and perhaps our ability to create new therapies.”

Anorexia is a disease that affects 1% of the global population and although therapy can be an effective treatment for some, many do not make a full recovery. Stem cell-based models could prove to be a new method for unlocking new clues into what causes anorexia and what can cure it.

Nature versus Zika, who will win?

Zika virus is no longer dominating the news headlines these days compared to 2015 when large outbreaks of the virus in the Southern hemisphere came to a head. However, the threat of Zika-induced birth defects, like microcephaly to pregnant women and their unborn children is no less real or serious two years later. There are still no effective vaccines or antiviral drugs that prevent Zika infection but scientists are working fast to meet this unmet need.

Speaking of which, scientists at UCLA think they might have a new weapon in the war against Zika. Back in 2013, they reported that a natural compound in the body called 25HC was effective at attacking viruses and prevented human cells from being infected by viruses like HIV, Ebola and Hepatitis C.

When the Zika outbreak hit, they thought that this compound could potentially be effective at preventing Zika infection as well. In their new study published in the journal Immunity, they tested a synthetic version of 25HC in animal and primate models, they found that it protected against infection. They also tested the compound on human brain organoids, or mini brains in a dish made from pluripotent stem cells. Brain organoids are typically susceptible to Zika infection, which causes substantial cell damage, but this was prevented by treatment with 25HC.

Left to right: (1) Zika virus (green) infects and destroys the formation of neurons (pink) in human stem cell-derived brain organoids.  (2) 25HC blocks Zika infection and preserves neuron formation in the organoids. (3) Reduced brain size and structure in a Zika-infected mouse brain. (4) 25HC preserves mouse brain size and structure. Image courtesy of UCLA Stem Cell.

A UCLA news release summarized the impact that this research could have on the prevention of Zika infection,

“The new research highlights the potential use of 25HC to combat Zika virus infection and prevent its devastating outcomes, such as microcephaly. The research team will further study whether 25HC can be modified to be even more effective against Zika and other mosquito-borne viruses.”

Harnessing a naturally made weapon already found in the human body to fight Zika could be an alternative strategy to preventing Zika infection.

Gene therapy in stem cells gives hope to bubble-babies.

Last week, an inspiring and touching story was reported by Erin Allday in the San Francisco Chronicle. She featured Ja’Ceon Golden, a young baby not even 6 months old, who was born into a life of isolation because he lacked a properly functioning immune system. Ja’Ceon had a rare disease called severe combined immunodeficiency (SCID), also known as bubble-baby disease.

 

Ja’Ceon Golden is treated by patient care assistant Grace Deng (center) and pediatric oncology nurse Kat Wienskowski. Photo: Santiago Mejia, The Chronicle.

Babies with SCID lack the body’s immune defenses against infectious diseases and are forced to live in a sterile environment. Without early treatment, SCID babies often die within one year due to recurring infections. Bone marrow transplantation is the most common treatment for SCID, but it’s only effective if the patient has a donor that is a perfect genetic match, which is only possible for about one out of five babies with this disease.

Advances in gene therapy are giving SCID babies like Ja’Ceon hope for safer, more effective cures. The SF Chronicle piece highlights two CIRM-funded clinical trials for SCID run by UCLA in collaboration with UCSF and St. Jude Children’s Research Hospital. In these trials, scientists isolate the bone marrow stem cells from SCID babies, correct the genetic mutation causing SCID in their stem cells, and then transplant them back into the patient to give them a healthy new immune system.

The initial results from these clinical trials are promising and support other findings that gene therapy could be an effective treatment for certain genetic diseases. CIRM’s Senior Science Officer, Sohel Talib, was quoted in the Chronicle piece saying,

“Gene therapy has been shown to work, the efficacy has been shown. And it’s safe. The confidence has come. Now we have to follow it up.”

Ja’Ceon was the first baby treated at the UCSF Benioff Children’s Hospital and so far, he is responding well to the treatment. His great aunt Dannie Hawkins said that it was initially hard for her to enroll Ja’Ceon in this trial because she was a partial genetic match and had the option of donating her own bone-marrow to help save his life. In the end, she decided that his involvement in the trial would “open the door for other kids” to receive this treatment if it worked.

Ja’Ceon Golden plays with patient care assistant Grace Deng in a sterile play area at UCSF Benioff Children’s Hospital.Photo: Santiago Mejia, The Chronicle

It’s brave patients and family members like Ja’Ceon and Dannie that make it possible for research to advance from clinical trials into effective treatments for future patients. We at CIRM are eternally grateful for their strength and the sacrifices they make to participate in these trials.

A Clinical Trial Network Focused on Stem Cell Treatments is Expanding

Geoff Lomax is a Senior Officer of CIRM’s Strategic Initiatives.

California is one of the world-leaders in advancing stem cell research towards treatments and cures for patients with unmet medical needs. California has scientists at top universities and companies conducting cutting edge research in regenerative medicine. It also has CIRM, California’s Stem Cell Agency, which funds promising stem cell research and is advancing stem cell therapies into clinical trials. But the real clincher is that California has something that no one else has: a network of medical centers dedicated to stem cell-based clinical trials for patients. This first-of-its-kind system is called the CIRM Alpha Stem Cell Clinics Network.

Get to Know Our Alpha Clinics

In 2014, CIRM launched its Alpha Stem Cell Clinics Network to accelerate the development and delivery of stem cell treatments to patients. The network consists of three Alpha Clinic sites at UC San Diego, City of Hope in Duarte, and a joint clinic between UC Los Angeles and UC Irvine. Less than three years since its inception, the Alpha Clinics are conducting 34 stem cell clinical trials for a diverse range of diseases such as cancer, heart disease and sickle cell anemia. You can find a complete list of these clinical trials on our Alpha Clinics website. Below is an informational video about our Alpha Clinics Network.

So far, hundreds of patients have been treated at our Alpha Clinics. These top-notch medical centers use CIRM-funding to build teams specialized in overseeing stem cell trials. These teams include patient navigators who provided in-depth information about clinical trials to prospective patients and support them during their treatment. They also include pharmacists who work with patients’ cells or manufactured stem cell-products before the therapies are given to patients. And lastly, let’s not forget the doctors and nurses that are specially trained in the delivery of stem cell therapies to patients.

The Alpha Clinics Network also offers resources and tools for clinical trial sponsors, the people responsible for conducting the trials. These include patient education and recruitment tools and access to over 20 million patients in California to support successful recruitment. And because the different clinical trial sites are in the same network, sponsors can benefit from sharing the same approval measures for a single trial at multiple sites.

Looking at the big picture, our Alpha Clinics Network provides a platform where patients can access the latest stem cell treatments, and sponsors can access expert teams at multiple medical centers to increase the likelihood that their trial succeeds.

The Alpha Clinics Network is expanding

This collective expertise has resulted in a 3-fold (from 12 to 36 – two trials are being conducted at two sites) increase in the number of stem cell clinical trials at the Alpha Clinic sites since the Network’s inception. And the number continues to rise every quarter. Given this impressive track record, CIRM’s Board voted in February to expand our Alpha Clinics Network. The Board approved up to $16 million to be awarded to two additional medical centers ($8 million each) to create new Alpha Clinic sites and work with the current Network to accelerate patient access to stem cell treatments.

CIRM’s Chairman Jonathan Thomas explained,

Jonathan Thomas

“We laid down the foundation for conducting high quality stem cell trials when we started this network in 2014. The success of these clinics in less than three years has prompted the CIRM Board to expand the Network to include two new trial sites. With this expansion, CIRM is building on the current network’s momentum to establish new and better ways of treating patients with stem cell-based therapies.”

The Alpha Clinics Network plays a vital role in CIRM’s five-year strategic plan to fund 50 new clinical trials by 2020. In fact, the Alpha Clinic Network supports clinical trials funded by CIRM, industry sponsors and other sources. Thus, the Network is on track to becoming a sustainable resource to deliver stem cell treatments indefinitely.

In addition to expanding CIRM’s Network, the new sites will develop specialized programs to train doctors in the design and conduct of stem cell clinical trials. This training will help drive the development of new stem cell therapies at California medical centers.

Apply to be one our new Alpha Clinics!

For the medical centers interested in joining the CIRM Alpha Stem Cell Clinics Network, the deadline for applications is May 15th, 2017. Details on this funding opportunity can be found on our funding page.

The CIRM Team looks forward to working with prospective applicants to address any questions. The Alpha Stem Cell Clinics Network will also be showcasing it achievement at its Second Annual Symposium, details may be found on the City of Hope Alpha Clinics website.

City of Hope Medical Center and Alpha Stem Cell Clinic


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3D printing blood vessels: a key step to solving the organ donor crisis

About 120,000 people in the U.S. are on a waiting list for an organ donation and every day 22 of those people will die because there aren’t enough available organs. To overcome this organ donor crisis, bioengineers are working hard to develop 3D printing technologies that can construct tissues and organs from scratch by using cells as “bio-ink”.

Though each organ type presents its own unique set of 3D bioprinting challenges, one key hurdle they all share is ensuring that the transplanted organ is properly linked to a patient’s  circulatory system, also called the vasculature. Like the intricate system of pipes required to distribute a city’s water supply to individual homes, the blood vessels of our circulatory system must branch out and reach our organs to provide oxygen and nutrients via the blood. An organ won’t last long after transplantation if it doesn’t establish this connection with the vasculature.

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Digital model of blood vessel network. Photo: Erik Jepsen/UC San Diego Publications

In a recent UC San Diego (UCSD) study, funded in part by CIRM, a team of engineers report on an important first step toward overcoming this challenge: they devised a new 3D bioprinting method to recreate the complex architecture of blood vessels found near organs. This type of 3D bioprinting approach has been attempted by other labs but these earlier methods only produced simple blood vessel shapes that were costly and took hours to fabricate.  The UCSD team’s home grown 3D bioprinting process, in comparison, uses inexpensive components and only takes seconds to complete. Wei Zhu, the lead author on the Biomaterials publication, expanded on this comparison in a press release:

wzhu

Wei Zhu

“We can directly print detailed microvasculature structures in extremely high resolution. Other 3D printing technologies produce the equivalent of ‘pixelated’ structures in comparison and usually require … additional steps to create the vessels.”

 

As a proof of principle, the bioprinted vessel structures – made with two human cell types found in blood vessels – were transplanted under the skin of mice. After two weeks, analysis of the skin showed that the human grafts were thriving and had integrated with the mice’s blood vessels. In fact, the presence of red blood cells throughout these fused vessels provided strong evidence that blood was able to circulate through them. Despite these promising results a lot of work remains.

3d-printing-blood-vessels-3

Microscopic 3D printed blood vessel structure. Photo: Erik Jepsen/UC San Diego Publications

As this technique comes closer to a reality, the team envisions using induced pluripotent stem cells to grow patient-specific organs and vasculature which would be less likely to be rejected by the immune system.

schen

Shaochen Chen

“Almost all tissues and organs need blood vessels to survive and work properly. This is a big bottleneck in making organ transplants, which are in high demand but in short supply,” says team lead Shaochen Chen. “3D bioprinting organs can help bridge this gap, and our lab has taken a big step toward that goal.”

 

We eagerly await the day when those transplant waitlists become a thing of the past.

The power of the patient’s voice: how advocates shape clinical trials and give hope to those battling deadly diseases

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The Stack family: L to R Alex, Natalie, Nancy & Jeff

Tennis great Martina Navratilova was once being interviewed about what made her such a great competitor and she said it was all down to commitment. When pressed she said “the difference between involvement and commitment is like ham and eggs; the chicken is involved but the pig is committed.”

That’s how I feel about the important role that patients and patient advocates play in the work that we do at CIRM. Those of us who work here are involved. The patients and patient advocates are committed. This isn’t just their life’s work;  it’s their life.

I was reminded of that last week when I had the privilege of talking with Nancy Stack, the Patient Representative on a Clinical Advisory Panel (CAP) we have created for a program to treat cystinosis. She has an amazing story to tell. But before we get to that I have to do a little explaining.

Cystinosis is a rare disease, affecting maybe only 2,000 people worldwide, that usually strikes children before they are two years old and can lead to end stage kidney failure before their tenth birthday. Current treatments are limited, which is why the average life expectancy for someone with this is only around 27 years.

When we fund a project that is already in, or hoping to be in, a clinical trial we create a CAP to help assist the team behind the research. The CAP consists of a CIRM Science Officer, an independent scientific expert in this case for cystinosis, and a Patient Representative.

The patient’s voice

The Patient Representative’s role is vital because they can help the researchers understand the needs of the patient and take those needs into account when designing the trial. In the past, many researchers had little contact with patients and so designed the trial around their own needs. The patients had to fit into that model. We think it should be the other way around; that the model should fit the patients. The Patient Representatives help us make that happen.

Nancy Stack did just that. At the first meeting of the CAP she showed up with a list of 38 questions that she and other families with cystinosis had come up with for the researchers. They went from the blunt – “Will I die from the treatment” – to the practical –  “How will children/teens keep up with school during the process?” – and included a series of questions from a 12-year old girl with the disease – “Will I lose my hair because I’ve been growing it out for a long time? Will I feel sick? Will it hurt?”

Nancy says the questions are not meant to challenge the researcher, in this case U.C. San Diego’s Stephanie Cherqui, but to ensure that if the trial is given the go-ahead by the US Food and Drug Administration (FDA) that every patient who signs up for it knows exactly what they are getting into. That’s particularly important because many of those could be children or teenagers.

Fully informed

“As parents we know the science is great and is advancing, but we have real people who are going to go through this treatment so we have a responsibility to know what will it mean to them. Patients know they could die of the disease and so this research has real world implications for them.”

“I think without this, without allowing the patients voice to be heard, you would have a hard time recruiting patients for this kind of clinical trial.”

Nancy says not only was Dr. Cherqui not surprised by the questions, she welcomed them. Dr. Cherqui has been supported and funded by the Cystinosis Research Foundation for years and Nancy says she regards the patients and patient advocates as partners in this journey:

“She knows we are not challenging her, we’re supporting her and helping her cover every aspect of the research to help make it work.”

Nancy became committed to finding a cure for cystinosis when her daughter, Natalie, was diagnosed with the condition when she was just 7 months old. The family were handed a pamphlet titled “What to do when your child has a terminal disease” and told there was no cure.

Birthday wish

In 2003, on the eve of her 12th birthday, Nancy asked Natalie what her wish was for her birthday. She wrote on a napkin “to have my disease go away forever.” The average life expectancy for people with cystinosis at that point was 18. Nancy told her husband “We have to do something.”

They launched the Cystinosis Research Foundation and a few weeks later they held their first fundraiser. That first year they raised $427,000, an impressive amount for such a rare disease. Last year they raised $4.94 million. Every penny of that $4.94 million goes towards research, making them the largest funders of cystinosis research in the world.

“We learned that for there to be hope there has to be research, and to do research we needed to raise funds. Without that we knew our children would not survive this disease.”

Natalie is now 26, a graduate of Georgetown and USC, and about to embark on a career in social work. Nancy knows many others are not so fortunate:

“Every year we lose some of our adults, even some of our teens, and that is unbelievably hard. Those other children, wherever they may live, they are my children too. We are all connected to each other and that’s what motivates me every day. Having a child with this disease means that time is running out and there must be a commitment to work hard every day to find a cure, and never giving up until you do.”

That passion for the cause, that compassion for others and determination to help others makes the Patient Representative on the CAP so important. They are a reminder that we all need to work as hard as we can, as fast as we can, and do everything we can to help these trials succeed.

And we are committed to doing that.


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Avalanches of exciting new stem cell research at the Keystone Symposia near Lake Tahoe

From January 8th to 13th, nearly 300 scientists and trainees from around the world ascended the mountains near Lake Tahoe to attend the joint Keystone Symposia on Neurogenesis and Stem Cells at the Resort at Squaw Creek. With record-high snowfall in the area (almost five feet!), attendees had to stay inside to stay warm and dry, and even when we lost power on the third day on the mountain there was no shortage of great science to keep us entertained.

Boy did it snow at the Keystone Conference in Tahoe!

Boy did it snow at the Keystone Conference in Tahoe!

One of the great sessions at the meeting was a workshop chaired by CIRM’s Senior Science Officer, Dr. Kent Fitzgerald, called, “Bridging and Understanding of Basic Science to Enable/Predict Clinical Outcome.” This workshop featured updates from the scientists in charge of three labs currently conducting clinical trials funded and supported by CIRM.

Regenerating injured connections in the spinal cord with neural stem cells

Mark Tuszynski, UCSD

Mark Tuszynski, UCSD

The first was a stunning talk by Dr. Mark from UCSD who is investigating how neural stem cells can help outcomes for those with spinal cord injury. The spinal cord contains nerves that connect your brain to the rest of your body so you can sense and move around in your environment, but in cases of severe injury, these connections are cut and the signal is lost. The most severe of these injuries is a complete transection, which is when all connections have been cut at a given spot, meaning no signal can pass through, just like how no cars could get through if a section of the Golden Gate Bridge was missing. His lab works in animal models of complete spinal cord transections since it is the most challenging to repair.

As Dr. Tuszynski put it, “the adult central nervous system does not spontaneously regenerate [after injury], which is surprising given that it does have its own set of stem cells present throughout.” Their approach to tackle this problem is to put in new stem cells with special growth factors and supportive components to let this process occur.

Just as most patients wouldn’t be able to come in for treatment right away after injury, they don’t start their tests until two weeks after the injury. After that, they inject neural stem cells from either the mouse, rat, or human spinal cord at the injury site and then wait a bit to see if any new connections form. Their group has shown very dramatic increases in both the number of new connections that regenerate from the injury site and extend much further than previous efforts have shown. These connections conduct electrochemical messages as normal neurons do, and over a year later they see no functional decline or tumors forming, which is often a concern when transplanting stem cells that normally like to divide a lot.

While very exciting, he cautions, “this research shows a major opportunity in neural repair that deserves proper study and the best clinical chance to succeed”. He says it requires thorough testing in multiple animal models before going into humans to avoid a case where “a clinical trial fails, not because the biology is wrong, but because the methods need tweaking.”

Everyone needs support – even dying cells

The second great talk was by Dr. Clive Svendsen of Cedars-Sinai Regenerative Medicine Institute on how stem cells might help provide healthy support cells to rescue dying neurons in the brains of patients with neurodegenerative diseases like Amyotrophic Lateral Sclerosis (ALS) and Parkinson’s. Some ALS cases are hereditary and would be candidates for a treatment using gene editing techniques. However, around 90 percent of ALS cases are “sporadic” meaning there is no known genetic cause. Dr. Svendsen explained how in these cases, a stem cell-based approach to at least fix the cellular cause of the disease, would be the best option.

While neurons often capture all the attention in the brain, since they are the cells that actually send messages that underlie our thoughts and behaviors, the Svendsen lab spends a great deal of time thinking about another type of cell that they think will be a powerhouse in the clinic: astrocytes. Astrocytes are often labeled as the support cells of the brain as they are crucial for maintaining a balance of chemicals to keep neurons healthy and functioning. So Dr. Svendsen reasoned that perhaps astrocytes might unlock a new route to treating neurodegenerative diseases where neurons are unhealthy and losing function.

ALS is a devastating disease that starts with early muscle twitches and leads to complete paralysis and death usually within four years, due to the rapid degeneration of motor neurons that are important for movement all over the body. Svendsen’s team found that by getting astrocytes to secrete a special growth factor, called “GDNF”, they could improve the survival of the neurons that normally die in their model of ALS by five to six times.

After testing this out in several animal models, the first FDA-approved trial to test whether astrocytes from fetal tissue can slow spinal motor neuron loss will begin next month! They will be injecting the precursor cells that can make these GDNF-releasing astrocytes into one leg of ALS patients. That way they can compare leg function and track whether the cells and GDNF are enough to slow the disease progression.

Dr. Svendsen shared with us how long it takes to create and test a treatment that is committed to safety and success for its patients. He says,

Clive Svendsen has been on a 15-year quest to develop an ALS therapy

Clive Svendsen 

“We filed in March 2016, submitted the improvements Oct 2016, and we’re starting our first patient in Feb 2017. [One document is over] 4500 pages… to go to the clinic is a lot of work. Without CIRM’s funding and support we wouldn’t have been able to do this. This isn’t easy. But it is doable!”

 

Improving outcomes in long-term stroke patients in unknown ways

Gary Steinberg

Gary Steinberg

The last speaker for the workshop, Dr. Gary Steinberg, a neurosurgeon at Stanford who is looking to change the lives of patients with severe limitations after having a stroke. The deficits seen after a stroke are thought to be caused by the death of neurons around the area where the stroke occurred, such that whatever functions they were involved with is now impaired. Outcomes can vary for stroke patients depending on how long it takes for them to get to the emergency department, and some people think that there might be a sweet spot for when to start rehabilitative treatments — too late and you might never see dramatic recovery.

But Dr. Steinberg has some evidence that might make those people change their mind. He thinks, “these circuits are not irreversibly damaged. We thought they were but they aren’t… we just need to continue figuring out how to resurrect them.”

He showed stunning videos from his Phase 1/2a clinical trial of several patients who had suffered from a stroke years before walking into his clinic. He tested patients before treatment and showed us videos of their difficulty to perform very basic movements like touching their nose or raising their legs. After carefully injecting into the brain some stem cells taken from donors and then modified to boost their ability to repair damage, he saw a dramatic recovery in some patients as quickly as one day later. A patient who couldn’t lift her leg was holding it up for five whole seconds. She could also touch her arm to her nose, whereas before all she could do was wiggle her thumb. One year later she is even walking, albeit slowly.

He shared another case of a 39 year-old patient who suffered a stroke didn’t want to get married because she felt she’d be embarrassed walking down the aisle, not to mention she couldn’t move her arm. After Dr. Steinberg’s trial, she was able to raise her arm above her head and walk more smoothly, and now, four years later, she is married and recently gave birth to a boy.

But while these studies are incredibly promising, especially for any stroke victims, Dr. Steinberg himself still is not sure exactly how this stem cell treatment works, and the dramatic improvements are not always consistent. He will be continuing his clinical trial to try to better understand what is going on in the injured and recovering brain so he can deliver better care to more patients in the future.

The road to safe and effective therapies using stem cells is long but promising

These were just three of many excellent presentations at the conference, and while these talks involved moving science into human patients for clinical trials, the work described truly stands on the shoulders of all the other research shared at conferences, both present and past. In fact, the reason why scientists gather at conferences is to give one another feedback and to learn from each other to better their own work.

Some of the other exciting talks that are surely laying down the framework for future clinical trials involved research on modeling mini-brains in a dish (so-called cerebral organoids). Researchers like Jürgen Knoblich at the Institute of Molecular Biotechnology in Austria talked about the new ways we can engineer these mini-brains to be more consistent and representative of the real brain. We also heard from really fundamental biology studies trying to understand how one type of cell becomes one vs. another type using the model organism C. elegans (a microscopic, transparent worm) by Dr. Oliver Hobert of Columbia University. Dr. Austin Smith, from the University of Cambridge in the UK, shared the latest about the biology of pluripotent cells that can make any cell type, and Stanford’s Dr. Marius Wernig, one of the meeting’s organizers, told us more of what he’s learned about the road to reprogramming an ordinary skin cell directly into a neuron.

Stay up to date with the latest research on stem cells by continuing to follow this blog and if you’re reading this because you’re considering a stem cell treatment, make sure you find out what’s possible and learn about what to ask by checking out closerlookatstemcells.org.


Samantha Yammine

Samantha Yammine

Samantha Yammine is a science communicator and a PhD candidate in Dr. Derek van der Kooy’s lab at the University of Toronto. You can learn more about Sam and her research on her website.

Stem cell stories that caught our eye: Blood stem cells on a diet, Bladder control after spinal cord injuries, new ALS insights

Putting blood stem cells on a diet. (Karen Ring)

valine

Valine. Image: BMRB

Scientists from Stanford and the University of Tokyo have figured out a new way to potentially make bone marrow transplants more safe. Published yesterday in the journal Science, the teams discovered that removing an essential amino acid, called valine, from the diets of mice depleted their blood stem cells and made it easier for them to receive bone marrow transplants from other mice without the need for radiation or chemotherapy. Removing valine from human blood stem cells yielded similar results suggesting that this therapeutic approach could potentially change and improve the way that certain cancer patients are treated.

In an interview with Science Magazine, senior author Satoshi Yamazaki explained how current bone marrow transplants are toxic to patients and that an alternative, safer form of treatment is needed.

“Bone marrow transplantation is a toxic therapy. We have to do it to treat diseases that would otherwise be fatal, but the quality of life afterward is often not good. Relative to chemotherapy or radiation, the toxicity of a diet deficient in valine seems to be much, much lower. Mice that have been irradiated look terrible. They can’t have babies and live for less than a year. But mice given a diet deficient in valine can have babies and will live a normal life span after transplantation.”

The scientists found that the effects of a valine-deficient diet were mostly specific to blood stem cells in the mice, but also did affect hair stem cells and some T cells. The effects on these other populations of cells were not as dramatic however as the effects on blood stem cells.

Going forward, the teams are interested to find out whether valine deficiency will be a useful treatment for leukemia stem cells, which are stem cells that give rise to a type of blood cancer. As mentioned before, this alternative form of treatment would be very valuable for certain cancer patients in comparison to the current regimen of radiation treatment before bone marrow transplantation.

Easing pain and improving bladder control in spinal cord injury (Kevin McCormack)
When most people think of spinal cord injuries (SCI) they focus on the inability to walk. But for people with those injuries there are many other complications such as intense nerve or neuropathic pain, and inability to control their bladder. A CIRM-funded study from researchers at UCSF may help point at a new way of addressing those problems.

The study, published in the journal Cell Stem Cell, zeroed in on the loss in people with SCI of a particular amino acid called GABA, which acts as a neurotransmitter in the central nervous system and inhibits nerve transmission in the brain, calming nervous activity.

Here’s where we move into alphabet soup, but stick with me. Previous studies showed that using cells called inhibitory interneuron precursors from the medial ganglionic eminence (MGE) helped boost GABA signaling in the brain and spinal cord. So the researchers turned some human embryonic stem cells (hESCs) into MGEs and transplanted those into the spinal cords of mice with SCI.

Six months after transplantation those cells had integrated into the mice’s spinal cord, and the mice not only showed improved bladder function but they also seemed to have less pain.

Now, it’s a long way from mice to men, and there’s a lot of work that has to be done to ensure that this is safe to try in people, but the researchers conclude: “Our findings, therefore, may have implications for the treatment of chronically spinal cord-injured patients.”

CIRM-funded study reveals potential new ALS drug target (Todd Dubnicoff)
Of the many diseases CIRM-funded researchers are tackling, Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s Disease, has got to be one of the worst.

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Motor neurons derived from skin cells of a healthy donor
Image: UC San Diego

This neurodegenerative disorder attacks and kills motor neurons, the nerve cells that control voluntary muscle movement. People diagnosed with ALS, gradually lose the ability to move their limbs, to swallow and even to breathe. The disease is always fatal and people usually die within 3 to 5 years after initial diagnosis. There’s no cure for ALS mainly because scientists are still struggling to fully understand what causes it.

Stem cell-derived “disease in a dish” experiments have recently provided many insights into the underlying biology of ALS. In these studies, skin cells from ALS patients are reprogrammed into an embryonic stem cell-like state called induced pluripotent stem cells (iPSCS). These iPS cells are grown in petri dishes and then specialized into motor neurons, allowing researchers to carefully look for any defects in the cells.

This week, a UC San Diego research team using this disease in a dish strategy reported they had uncovered a cellular process that goes haywire in ALS cells. The researchers generated motor neurons from iPS cells that had been derived from the skin samples of ALS patients with hereditary forms of the disease as well as samples from healthy donors. The team then compared the activity of thousands of genes between the ALS and healthy motor neurons. They found that a particular hereditary mutation doesn’t just impair a protein called hnRNP A2/B1, it actually gives the protein new toxic activities that kill off the motor neurons.

Fernando Martinez, the first author on this study in Neuron, told the UC San Diego Health newsroom that these news results reveal an important context for their on-going development of therapeutics that target proteins like hnRNP:

“These … therapies [targeting hnRNP] can eliminate toxic proteins and treat disease. But this strategy is only viable if the proteins have gained new toxic functions through mutation, as we found here for hnRNP A2/B1 in these ALS cases.”

Stem cell stories that caught our eye: relief for jaw pain, vitamins for iPSCs and Alzheimer’s insights

Jaw bone stem cells may offer relief for suffers of painful joint disorder
An estimated 10 million people in the US – mostly women –  suffer from problems with their temporomandibular joint (TMJ) which sits between the jaw bone and skull. TMJ disorders can lead to a number of symptoms such as intense pain in the jaw, face and head; difficulty swallowing and talking; and dizziness.

ds00355_im00012_mcdc7_tmj_jpgThe TMJ is made up of fibrocartilage which, when healthy, acts as a cushion to enable a person to move their jaw smoothly. But this cartilage doesn’t have the capacity to heal or regenerate so treatments including surgery and pain killers only mask the symptoms without fixing the underlying damage of the joint.

Reporting this week in Nature Communications, researchers at Columbia University’s College of Dental Medicine identified stem cells within the TMJ that can form cartilage and bone – in cell culture studies as well as in animals. The research team further showed that the signaling activity of a protein called Wnt leads to a reduction of these fibrocartilage stem cells (FSCSs) in animals and as a result causes deterioration of cartilage. But injecting a known inhibitor of Wnt into the animals’ damaged TMJ spurred growth and healing of the joint.

The team is now in search of other Wnt inhibitors that could be used in a clinical setting. In a university press release, Jeremy Mao, a co-author on the paper, talked about the implications of these results:

“They suggest that molecular signals that govern stem cells may have therapeutic applications for cartilage and bone regeneration. Cartilage and certain bone defects are notoriously difficult to heal.”

Take your vitamins: good advice for people and iPS cells
From a young age, we’re repeatedly told how getting enough vitamins each day is important for a healthy life. Our bodies don’t produce these naturally occurring chemicals but they carry out critical biochemical activities to keep our cells and organs functioning properly.

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Carrots: a great source of vitamin A. Image source: Wikimedia Commons

Well, it turns out that vitamins are also an important ingredient in stem cell research labs. Results published the Proceedings of the National Academy of Sciences (PNAS) this week by scientists in the UK and New Zealand show that vitamin A and C work together synergistically to improve the efficiency of reprogramming adult cells, like skin or blood, into the embryonic stem cell-like state of induced pluripotent stem cells (iPSCs).

By the time a stem cell has specialized into, let’s say, a skin cell, only skin cell-specific genes are active while others genes, like those needed for liver function, are shut down. Those non-skin genes are silenced through the attachment of chemical tags on the DNA, a process called methylation. It essentially provides the DNA with the means of maintaining a skin cell “memory”. To convert a skin cell back into a stem cell-like state, researchers in the lab must erase this “memory” by adding factors which demethylate, or remove the methylation tags on the silenced, non-skin related genes.

In the current research picked up by Science Daily, the researchers found that both vitamin A and C increase demethylation but in different ways. The study showed that vitamin A acts to increase the production of proteins that are important for demethylation while vitamin C acts to enhance the enzymatic activity of demethylation.

These insights may help add to the growing knowledge on how to most efficiently reprogram adult cells into iPSCs. And they may prove useful for a better understanding of certain cancers which contain cells that are essentially reprogrammed into a stem cell-like state.

New angles for dealing with the tangles in the Alzheimer’s brain
The memory loss and overall degradation of brain function seen in people with Alzheimer’s Disease (AD) is thought to be caused by the accumulation of amyloid and tau proteins which form plaques and tangles in the brain. These abnormal structures are toxic to brain cells and ultimately lead to cell death.

But other studies of post-mortem AD brains suggest a malfunction in endocytosis – a process of taking up and transporting proteins to different parts of the cell – may also play a role. While follow up studies corroborated this initial observation, they didn’t look at endocytosis in nerve cells so it remained unclear how much of a role it played in AD.

In a CIRM-funded study published this week in Cell Reports, UC San Diego researchers made nerve cells from human iPSCs and used the popular CRISPR and TALEN gene editing techniques to generate mutations seen in inherited forms of AD. One of those inherited mutations is in the PS1 gene which has been shown to play a role in transporting amyloid proteins in nerve cells. The research confirmed that this mutation as well as a mutation in the amyloid precursor protein (APP) led to a breakdown in the proper trafficking of APP within the mutated nerve cells. In fact, they found an accumulation of APP in a wrong area of the nerve cell. However, blocking the action of a protein called secretase that normally processes the APP protein helped restore proper protein transport. In a university press release, team leader Larry Goldstein, explained the importance of these findings:

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Larry Goldstein.
Image: UCSD

“Our results further illuminate the complex processes involved in the degradation and decline of neurons, which is, of course, the essential characteristic and cause of AD. But beyond that, they point to a new target and therapy for a condition that currently has no proven treatment or cure.”

 

 

Gene required for sperm stem cells linked to male infertility, UCSD study suggests

Even in this day and age, when a couple is having trouble conceiving a child, it’s often the woman who is initially suspected of having infertility problems and is likely the first to seek out the advice of doctor. But according to Miles Wilkinson, professor of reproductive medicine at UC San Diego School of Medicine, infertility issues can just as likely be due to problems with sperm production in the male. In fact, about 4 million men of reproductive age in the U.S. are confronted with infertility challenges and in 30% percent of those cases, the cause of the infertility is not well understood.

Through some scientific detective work, Wilkinson and his research team have zeroed in on a gene called RhoX10 that plays an essential role in the development of adult stem cells which give rise to sperm production. The study results, funded in part by CIRM and published yesterday in Cell Reports, may help provide a path toward new treatment options for male infertility.

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The process of sperm formation (spermatogenesis). Image: Wikipedia

To get at a cellular and molecular understanding of infertility, the team focused on the function of spermatogonial stem cells (SSCs). Through a multistep process within the male reproductive system, SSCs form into mature sperm cells capable of fertilizing an egg.  The SSC itself forms from primordial germ cells. The key genetic switches that help these germ cells give rise to SSCs was not well understood.  Earlier studies had shown that a group of adjacent genes, called the Rhox cluster, on the X-chromosome are expressed in the testes, suggesting a role in sperm production.

Using genetic engineering techniques, Wilkinson’s team bred mice lacking the 33 genes of the Rhox cluster. The resulting male mice showed a reduction in the number SSCs leading to low sperm number. Through a process of elimination, the team found that deleting just one of those genes, Rhox10, produced nearly the same flaw.

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Rhox 10: a genetic “bus” that “drives” sperm stem cells toward sperm production. Illustration by Hye-Won Song.

Further analysis, indicated Rhox10 was key to driving the development of germ cells into SSCs. So when the gene is deleted, not enough SSCs develop in the testis, leading to low sperm counts.  The researchers also found the Rhox10 is a master regulator of genes that control the germ cells’ movement from one part of the testis to another that, due to a different chemical environment, helps the germ cells transform into SSCs.

In addition to this mouse data, the team also co-authored a recent Human Molecular Genetics report with scientists at the University of Münster in Germany that connects Rhox genes and human male infertility. In the study, three RHOX genes were sequenced in 250 men with extremely low sperm counts and revealed six genetic mutations. Together, these results present solid evidence that mutations in Rhox are the culprit in at least some forms of male infertility. First author Hye-Won Song discussed this point in a university press release:

“Spermatogonial stem cells allow men — even in their 70s — to generate sperm and father children. Our finding that Rhox10 is critical for spermatogonial stem cells, coupled with the finding that human RHOX genes are mutated in infertile men, suggests that mutations in these genes cause human male infertility.”

Funding stem cell research targeting a rare and life-threatening disease in children

cystinosis

Photo courtesy Cystinosis Research Network

If you have never heard of cystinosis you should consider yourself fortunate. It’s a rare condition caused by an inherited genetic mutation. It hits early and it hits hard. Children with cystinosis are usually diagnosed before age 2 and are in end-stage kidney failure by the time they are 9. If that’s not bad enough they also experience damage to their eyes, liver, muscles, pancreas and brain.

The genetic mutation behind the condition results in an amino acid, cystine, accumulating at toxic levels in the body. There’s no cure. There is one approved treatment but it only delays progression of the disease, has some serious side effects of its own, and doesn’t prevent the need for a  kidney transplant.

Researchers at UC San Diego, led by Stephanie Cherqui, think they might have a better approach, one that could offer a single, life-long treatment for the problem. Yesterday the CIRM Board agreed and approved more than $5.2 million for Cherqui and her team to do the pre-clinical testing and work needed to get this potential treatment ready for a clinical trial.

Their goal is to take blood stem cells from people with cystinosis, genetically-modify them and return them to the patient, effectively delivering a healthy, functional gene to the body. The hope is that these genetically-modified blood stem cells will integrate with various body organs and not only replace diseased cells but also rescue them from the disease, making them healthy once again.

In a news release Randy Mills, CIRM’s President and CEO, said orphan diseases like cystinosis may not affect large numbers of people but are no less deserving of research in finding an effective therapy:

“Current treatments are expensive and limited. We want to push beyond and help find a life-long treatment, one that could prevent kidney failure and the need for kidney transplant. In this case, both the need and the science were compelling.”

The beauty of work like this is that, if successful, a one-time treatment could last a lifetime, eliminating or reducing kidney disease and the need for kidney transplantation. But it doesn’t stop there. The lessons learned through research like this might also apply to other inherited multi-organ degenerative disorders.

CIRM Grantees Reflect on Ten Years of iPS Cells

For the fourth entry for our “Ten Years of Induced Pluripotent Stem (iPS) Cells” series, which we’ve been posting all month, I reached out to three of our CIRM grantees to get their perspectives on the impact of iPSC technology on their research and the regenerative medicine field as a whole:

granteesStep back in time for us to August 2006 when the landmark Takahashi/Yamanaka Cell paper was published which described the successful reprogramming of adult skin cells into an embryonic stem cell-like state, a.k.a. induced pluripotent stem (iPS) cells. What do you remember about your initial reactions to the study?

Sheng Ding, MD, PhD
Senior Investigator, Gladstone Institute of Cardiovascular Disease
Shinya had talked about the (incomplete) iPS cell work well before his 2006 publication in several occasions, so seeing the paper was not a total surprise.

Alysson Muotri, PhD
Associate Professor, UCSD Dept. of Pediatrics/Cellular & Molecular Medicine
At that time, I was a postdoc. I was in a meeting when Shinya first presented his findings. I think he did not give the identity of the 4 factors at that time. I was very excited but remember hearing rumors in the corridors saying the data was too good to be true. Soon after, the publication come out and it was a lot of fun reading it.

Joseph Wu, MD, PhD
Director, Stanford Cardiovascular Institute
I remember walking to the parking lot after work. One of my colleagues called me on my cell phone and he asked if I had seen “the Cell paper” published earlier that day. I said I haven’t and I would look it up when I get back home. I read it that night and found it quite interesting because the concept was simple but yet powerful.

How soon after the publication did you start using the iPSC technique in your own research? At that time, what research questions were you able to start exploring that weren’t possible in the “pre-iPS” era?

Ding:
I think many of us in the (pluripotent stem cell) field quickly jumped on this seminal discovery and started working on the iPSC technology itself as, at the time, there were many aspects of the discovery that would need to be better understood and further improved for its applications.

Muotri:
Immediately after the first mouse Cell paper, but I started with human cells. There were some concerns if the 4 factors will also work in humans. Nonetheless, I start using the mouse cDNA factors in human cells and it worked! I was amazed to witness the transformation and see the iPSC colonies in my dish – I showed the results to everyone in the lab.

Soon after, the papers showing that the procedure worked in human cells were published but I already knew that. Thus, I started to apply this to model disease, my main focus. In 2010, we published the modeling of the first neurodevelopmental disease using the iPSC technology. It is still a landmark publication, and I am very happy to be among the pioneers who believed in the Yamanaka technology.

Wu:
We started working on iPS cells about a couple of months after the initial publication. To our surprise, it was incredibly easy to reproduce, and we were able to get successful clones after a few initial attempts, in part because we had already been working on human embryonic stem (ES) cells for several years.

I think the biggest advantage of iPS cells is that we can know the medical record of the donor. So we can study the correlation between the donor’s underlying genetic makeup and their resulting cellular and whole-body characteristics using iPS cells as a platform for integrating these analyses. Examining these correlations is simply not possible with ES cells since no adult donor exists.

Dr. Ding, what do you think made you and your research team especially skilled at pioneering the use of small molecules to replace the “Yamanaka” reprogramming factors?

Ding:
We had been working on identifying and using small molecules to modulate stem cell fate (including cell proliferation, differentiation, and reprogramming) before iPS cell technology was reported. So when the iPS cell work was reported, it was obvious to us that we could apply our expertise in small molecule discovery to better understand and improve iPS cell reprogramming and replace the genetic factors by pharmacological approaches.

Now, come back to the present and reflect on how the paper has impacted your research over the past 10 years. Describe some of the key findings your lab has made over the past 10 years through iPSC studies

Ding:
We’ve worked on three aspects that are related to iPS cell research: one is to identify small molecule drugs that can functionally replace the genetic reprogramming factors, and enhance reprogramming efficiency and iPS cell quality (to mitigate risks associated with genetic manipulation, to make the iPS cell generation process more robust and efficient, and reduce the cost etc).

Second is to better understand the reprogramming mechanisms, that would allow us to improve reprogramming and better utilize cellular reprogramming technology. For example, we had uncovered and characterized several fundamental mechanisms underlying the reprogramming process.

The third is to “repurpose/re-direct” the iPS cell reprogramming into directly generating tissue/organ-specific precursor cells without generating iPS cell (itself, which is tumorigenic and needs to be differentiated for most of its applications). This so-called “Cell-Activation and Signaling-Directed/CASD” reprogramming approach allowed us to directly generate cells in the brain, heart, pancreas, liver, and blood vessels.

Muotri:
My lab has focused on the use of iPS cells to model autism spectrum disorder, a condition that is very heterogeneous both clinically and genetically. Previous models for autism, such as animals and postmortem tissues, were limited because we could not have access to live neurons to test experimentally several hypotheses. Thus, the attractiveness of the iPS cell model, by capturing the genome of patients in pluripotent stem cells and then guide them to become neural networks.

While the modeling in a dish was a great potential, there were some clear limitations too: the variability in the system was too high for example. My lab has worked hard to develop a chemically-defined culture media (iDEAL) to grow iPS cells and reduce the variability in the system. Moreover, we have developed robust protocols to analyze the morphology and electrophysiological properties of cortical neurons derived from iPS cells. We have used these methods to learn more about how genes impact neuronal networks and to screen drugs for several diseases.

We also used these methods to create cerebral organoids or “mini-brains” in a dish and have applied this technology to test the impact of several genetic and environmental factors. For example, we recently showed that the Zika virus could target neural progenitor cells in these organoids, leading to defects in the human developing cortex. Without this technology, we would be limited to mouse models that do not recapitulate the microcephaly of the babies born in Brazil.

Wu:
Our lab has taken advantage of the iPS cell platform to better understand cardiovascular diseases and to advance the precision medicine initiative. For example, we have used iPS cells to elucidate the molecular mechanisms of diseases related to an enlarged heart, cardiac arrhythmias, viral- and chemotherapy-induced heart disease, the genetics of coronary artery disease, among other diseases. We have also used iPS cells for testing the safety and efficacy of various cardiovascular drugs (i.e., “clinical trial in a dish”).

How are your findings important in terms of accelerating stem cell treatments to patients with unmet medical needs?

Ding:
Better understanding the reprogramming process and developing small molecule drugs for enhancing reprogramming would allow more effective generation of safe stem cells with reduced cost for treating diseases or doing research.

Muotri:
We work with two concepts. First, we screen drugs that could repair the disorder at a cellular level in a dish, hoping these drugs will be useful for a large fraction of autistic individuals. This approach can also be used to stratify the autistic population, finding subgroups that are more responsive to a particular drug. This strategy should help future clinical trials.

In parallel, we also work with the idea of personalized medicine by using patient-derived cells to create “disease in a dish” models in the lab. We then examine the genomic information of these cells to help us find drugs that are more specific to that individual. This approach should allow us to better design the treatment, testing ideal drugs and dosage, before prescribing it to the patient.

Wu:
The iPS cell technology provides us with an unprecedented glimpse into cardiovascular developmental biology. With this knowledge, we should be able to better understand how cardiac and vascular cells regenerate in the heart during different phases of human life and also during times of stress such as in the case of a heart attack. However, to be able to translate this knowledge into clinical care for patients will take a significant amount of time. This is because we still need to tackle the issues of immunogenicity, tumorigenicity, and safety for products that are derived from ES and iPS cells. Equally importantly, we need to understand how transplanted cells integrate into the patient because based on our experience so far, most of the injected cells die upon transplant into the heart. Finally, the economics of this type of personalized regenerative medicine is a daunting challenge.

Finally, it’s foolhardy to predict the future but, just for fun, imagine that I revisit you in August 2026. What key iPSC-related accomplishments do you think your lab will achieve by then?

Ding:
We are hoping to have cell-based therapy and small molecule drugs developed based on iPS cell-related research for treating human diseases. Particularly, we are also hoping our cellular reprogramming research would lead us to identify and develop small molecule drugs that control tissue/organ regeneration in vivo [in an animal].

Muotri:
We hope to have improved several steps on the neural differentiation, dramatically reducing costs and increasing efficiency.

Wu:
We would like to use the iPS cell platform to discover several new drugs (or repurpose existing drugs) for our cardiovascular patients; to replace the current industry standard of drug toxicity testing using the hERG assay (which I believe is outdated); to predict what medications patients should be taking (i.e., precision cardiovascular medicine); and to elucidate risk index of genetic variants (in combination with genome editing approach).