Stem cell stories that caught our eye: glowing stem cells and new insights into Zika and SCID

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.

Glowing stem cells help scientists understand how cells work. (Karen Ring)
It’s easy to notice when something is going wrong. It’s a lot harder to notice when something is going right. The same thing can be said for biology. Scientists dedicate their careers to studying unhealthy cells, trying to understand why people get certain diseases and what’s going wrong at the cellular level to cause these problems. But there is a lot to be said for doing scientific research on healthy cells so that we can better understand what’s happening when cells start to malfunction.

A group from the Allen Institute for Cell Science is doing just this. They used a popular gene-editing technology called CRISPR/Cas9 to genetically modify human stem cell lines so that certain parts inside the cell will glow different colors when observed under a fluorescent microscope. Specifically, the scientists inserted the genetic code to produce fluorescent proteins in both the nucleus and the mitochondria of the stem cells. The final result is a tool that allows scientists to study how stem cells specialize into mature cells in various tissues and organs.

Glowing human stem cells. The edges of the cells are shown in purple while the DNA in the cell’s nucleus is in blue. (Allen Institute for Cell Science).

Glowing human stem cells. The edges of the cells are shown in purple while the DNA in the cell’s nucleus is in blue. (Allen Institute for Cell Science).

The director of stem cells and gene editing at the Allen Institute, Ruwanthi Gunawardane, explained how their technology improves upon previous methods for getting cells to glow in an interview with Forbes:

 “We’re trying to understand how the cell behaves, how it functions, but flooding it with some external protein can really mess it up. The CRISPR system allows us to go into the DNA—the blueprint—and insert a gene that allows the cell to express the protein in its normal environment. Then, through live imaging, we can watch the cell and understand how it works.”

The team has made five of these glowing stem cell lines available for use by the scientific community through the Coriell Institute for Medical Research (which also works closely with the CIRM iPSC Initiative). Each cell line is unique and has a different cellular structure that glows. You can learn more about these cell lines on the Coriell Allen Institute webpage and by watching this video:

 

Zika can take multiple routes to infect a child’s brain. (Kevin McCormack)
One of the biggest health stories of 2016 has been the rapid, indeed alarming, spread of the Zika virus. It went from an obscure virus to a global epidemic found in more than 70 countries.

The major concern about the virus is its ability to cause brain defects in the developing brain. Now researchers at Harvard have found that it can do this in more ways than previously believed.

Up till now, it was believed that Zika does its damage by grabbing onto a protein called AXL on the surface of brain cells called neural progenitor cells (NPCs). However, the study, published in the journal Cell Stem Cell, showed that even when AXL was blocked, Zika still managed to infiltrate the brain.

Using induced pluripotent stem cell technology, the researchers were able to create NPCs and then modify them so they had no AXL expression. That should, in theory, have been able to block the Zika virus. But when they exposed those cells to the virus they found they were infected just as much as ordinary brain cells exposed to the virus were.

Caption: Zika virus (light blue) spreads through a three-dimensional model of a developing brain. Image by Max Salick and Nathaniel Kirkpatrick/Novartis

Caption: Zika virus (light blue) spreads through a three-dimensional model of a developing brain. Image by Max Salick and Nathaniel Kirkpatrick/Novartis

In a story in the Harvard Gazette, Kevin Eggan, one of the lead researchers, said this shows scientists need to re-think their approach to countering the virus:

“Our finding really recalibrates this field of research because it tells us we still have to go and find out how Zika is getting into these cells.”

 

Treatment for a severe form of bubble baby disease appears on the horizon. (Todd Dubnicoff)
Without treatment, kids born with bubble baby disease typically die before reaching 12 months of age. Formally called severe combined immunodeficiency (SCID), this genetic blood disorder leaves infants without an effective immune system and unable to fight off even minor infections. A bone marrow stem cell transplant from a matched sibling can treat the disease but this is only available in less than 20 percent of cases and other types of donors carry severe risks.

In what is shaping up to be a life-changing medical breakthrough, a UCLA team has developed a stem cell/gene therapy treatment that corrects the SCID mutation. Over 40 patients have participated to date with a 100% survival rate and CIRM has just awarded the team $20 million to continue clinical trials.

There’s a catch though: other forms of SCID exist. The therapy described above treats SCID patients with a mutation in a gene responsible for producing a protein called ADA. But an inherited mutation in another gene called Artemis, leads to a more severe form of SCID. These Artemis-SCID infants have even less success with a standard bone marrow transplant compared to those with ADA-SCID. Artemis plays a role in DNA damage repair something that occurs during the chemo and radiation therapy sessions that are often necessary for blood marrow transplants. So Artemis-SCID patients are hyper-sensitive to the side of effects of standard treatments.

A recent study by UCSF scientists in Human Gene Therapy, funded in part by CIRM, brings a lot of hope to these Artemis-SCID patient. Using a similar stem cell/gene therapy method, this team collected blood stem cells from the bone marrow of mice with a form of Artemis-SCID. Then they added a good copy of the human Artemis gene to these cells. Transplanting the blood stem cells back to mice, restored their immune systems which paves the way for delivering this approach to clinic to also help the Artemis-SCID patients in desperate need of a treatment.

New iPS Insights: Cell Damage Enhances Reprogramming

Researchers learn a ton about the biological function of cells by studying them in vitro; that is, outside the body in a petri dish. But inside the body, or in vivo, cells respond to surrounding proteins and other cells that may be missing in an in vitro experiment. Important insights waiting to be revealed can easily be overlooked if a cell isn’t analyzed in the right context.

That’s the lesson learned from a recent study in Science looking at the induced pluripotent stem (iPS) cell process of reprogramming adult skin cells into an embryonic stem cell-like state. By examining this technique in laboratory mice, a research team at the Spanish National Cancer Research Centre (CNIO) showed that, compared to isolated cells in vitro, the efficiency of in vivo cellular reprogramming in the mice is boosted by nearby damaged cells. So injured cells appear to provide a signal to help kick start the regenerative process.

(Watch this video for a quick recap of the report or read on for a few more details)

The history of iPS cells in 30 seconds
But let’s a take a quick step back. Actually ten years back. That’s when Shinya Yamanaka discovered that the insertion of just four genes – let’s call them the Yamanaka genes – into adult skin cells in vitro can wipe their identities clean allowing them to be specialized into virtually any cell type. While this ground breaking work led to a Nobel Prize, the efficiency of the method was very low. Research in the past couple of years has shown in vivo reprogramming is also possible but also at a low efficiency.

So what’s behind the low efficiency? Some culprits include tumor suppressor proteins (which act like kill switches in cells to prevent them from turning into cancer) like p53 and INK4. Blocking the activity of either protein increases the efficiency of in vitro reprogramming. But a funny thing happened in the current study when the researchers did the same thing in vivo. They injected mouse skin cells with the Yamanaka reprogramming genes into mice lacking the p53 gene or the INK4 gene or into control mice with both genes intact. Compared to the control mice, in vivo reprogramming efficiency was higher in the mice missing the p53 gene, as you’d expect based on the in vitro results described above. But in mice without the INK4 gene, the efficiency was actually lower than the control. That’s the exact opposite of the in vitro case in which blocking INK4 increases reprogramming efficiency.

Who knew? Cell slow down stimulates the iPS process in surrounding cells
To investigate this baffling result, the team focused on the fact that INK4 plays a role in cell senescence. When cells get old or damaged they become senescent; that is, they stop dividing and release proteins that cause inflammation. Now, it turns out that in vivo, the Yamanaka genes not only drive reprogramming but they also lead to a lot of damage to surrounding cells causing them to senesce.

And herein lies the answer. The in vivo reprogramming efficiency appears to depend on surrounding cells becoming senescent. Cells in the mice lacking INK4 don’t senesce, and the resulting reprogramming efficiency is low. But in mice lacking p53, the team observed lots of senescent cells along with increased reprogramming efficiency.

By studying the various inflammation-causing proteins that senescent cells release, the team zeroed in on a protein called IL-6 as the connection between reprogramming and senescence. When IL-6 was blocked, in vivo reprogramming efficiency dropped. The team also mimicked these results in vitro. When damaged cells were present while reprogramming cells in the same petri dish, efficiency increased. And when IL-6 was removed from the nutrients the cells were grown in, in vitro reprogramming efficiency decreased.

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IL-6 released from damaged cells boosts reprogramming in surrounding cells with the potential for regenerative repair. (Image: Mosteiro et al. Science. 2016 Nov 25;354(6315))

Please note
It’s important to keep in mind that the end goal here is not to find ways to optimize the use of the Yamanaka genes for in vivo reprogramming efficiency in a clinical setting in people. Doing so would carry the dangerous risk of causing cancer. Instead, these results have revealed that senescent cells, through the action of IL-6, appear to stimulate the regeneration and repair of damaged or injured organs. A CNIO press release described how the scientists plan to apply these new insights:

“Having identified the essential role of IL6, … the team [is] now working on various pharmacological approaches to enhance the reprogramming efficiency, which could help to improve the regeneration of damaged tissue even in the absence of the Yamanaka genes. Improving the repairing capacity of tissues could have obvious implications for regenerative medicine, including the treatment of multiple pathologies and degenerative processes associated with ageing.”

Throwback Thursday: Progress to a Cure for Type 1 Diabetes

Welcome back to our “Throwback Thursday” series on the Stem Cellar. Over the years, we’ve accumulated an arsenal of valuable stem cell stories on our blog. Some of these stories represent crucial advances towards stem cell-based cures for serious diseases and deserve a second look.

novemberawarenessmonthThis week in honor of Diabetes Awareness Month, we are featuring type 1 diabetes (T1D), a chronic disease that destroys the insulin-producing beta cells in your pancreas. Without these important cells, patients cannot maintain the proper levels of glucose, a fancy name for sugar, in their blood and are at risk for many complications including heart disease, blindness, and even death.

Cell replacement therapy is evolving into an attractive option for patients with T1D. Replacing lost beta cells in the pancreas is a more permanent and less burdensome solution than the daily insulin shots (or insulin pumps) that many T1D patients currently take.

So let’s take a look at the past year’s advances in stem cell research for diabetes.

Making Insulin-Producing Cells from Stem Cells and Skin

This year, there were a lot of exciting studies that improved upon previous methods for generating pancreatic beta cells in a dish. Here’s a brief recap of a few of the studies we covered on our blog:

  • Make pancreatic cells from stem cells. Scientists from the Washington University School of Medicine in St. Louis and the Harvard Stem Cell Institute developed a method that makes beta cells from T1D patient-derived induced pluripotent stem cells (iPSCs) that behave very similarly to true beta cells both in a dish and when transplanted into diabetic mice. Their discovery has the potential to offer personalized stem cell treatments for patients with T1D in the near future and the authors of the study predicted that their technology could be ready to test in humans in the next three to five years.
  • Making functional pancreatic cells from skin. Scientists from the Gladstone Institutes used a technique called direct reprogramming to turn human skin cells directly into pancreatic beta cells without having to go all the way back to a pluripotent stem cell state. The pancreatic cells looked and acted like the real thing in a dish (they were able to secrete insulin when exposed to glucose), and they functioned normally when transplanted into diabetic mice. This study is exciting because it offers a new and more efficient method to make functioning human beta cells in mass quantities.

    Functioning human pancreatic cells after they’ve been transplanted into a mouse. (Image: Saiyong Zhu, Gladstone)

    Functioning human pancreatic cells after they’ve been transplanted into a mouse. (Image: Saiyong Zhu, Gladstone)

  • Challenges of stem cell-derived diabetes treatments. At this year’s Ogawa-Yamanaka Stem Cell Award ceremony Douglas Melton, a well-renowned diabetes researcher from Harvard, spoke about the main challenges for developing stem cell-derived diabetes treatments. The first is the need for better control over the methods that make beta cells from stem cells. The second was finding ways to make large quantities of beta cells for human transplantation. The last was finding ways to prevent a patient’s immune system from rejecting transplanted beta cells. Melton and other scientists are already working on improving techniques to make more beta cells from stem cells. As for preventing transplanted beta cells from being attacked by the patient’s immune system, Melton described two possibilities: using an encapsulation device or biological protection to mask the transplanted cells from an attack.

Progress to a Cure: Clinical Trials for Type 1 Diabetes

Speaking of encapsulation devices, CIRM is funding a Phase I clinical trial sponsored by a San Diego-based company called ViaCyte that’s hoping to develop a stem cell-based cure for patients with T1D. The treatment involves placing a small encapsulated device containing stem cell-derived pancreatic precursor cells under the skin of T1D patients. Once implanted, these precursor cells should develop into pancreatic beta cells that can secrete insulin into the patient’s blood stream. The goal of this trial is first to make sure the treatment is safe for patients and second to see if it’s effective in improving a patient’s ability to regulate their blood sugar levels.

To learn more about this exciting clinical trial, watch this fun video made by Youreka Science.

ViaCyte is still waiting on results for their Phase 1 clinical trial, but in the meantime, they are developing a modified version of their original device for T1D called PEC-Direct. This device also contains pancreatic precursor cells but it’s been designed in a way that allows the patient’s blood vessels to make direct connections to the cells inside the device. This vascularization process hopefully will improve the survival and function of the insulin producing beta cells inside the device. This study, which is in the last stage of research before clinical trials, is also being funded by CIRM, and we are excited to hear news about its progress next year.

ViaCyte's PEC-Direct device allows a patient's blood vessels to integrate and make contact with the transplanted beta cells.

ViaCyte’s PEC-Direct device allows a patient’s blood vessels to integrate and make contact with the transplanted beta cells.


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Stem cell stories that caught our eye: Amy Schumer’s MS fundraising; healing traumatic brain injury; schizophrenia iPS insights

Amy Schumer and Paul Shaffer raise money for MS. (Karen Ring)
Two famous individuals, one a comedian/movie star, the other a well-known musician, have combined forces to raise money for an important cause. Amy Schumer and Paul Shaffer have pledged to raise $2.5 million dollars to help support research into multiple sclerosis (MS). This disease affects the nerve cells in both the brain and spinal cord. It eats away at the protective myelin sheaths that coat and protect nerve cells and allow them to relay signals between the brain and the rest of the body. As a result, patients experience a wide range of symptoms including physical, mental and psychiatric problems.

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Comedian Amy Schumer and her Dad who has MS.
(National MS Society)

The jury is still out on the exact cause of MS and there is no cure available. But the Tisch MS Research Center of New York is trying to change that. It is “dedicated to finding the cause and cure for MS” and recently announced, at its annual Future Without MS Gala, that it has pledged to raise $10 million to fund the stem cell research efforts ongoing at the Center. Currently, Tisch is “the only center with an FDA approved stem cell clinical trial for MS in the United States.” You can read more about this clinical trial, which is transplanting mesenchymal stem cell-derived brain progenitor cells into the spinal cord, on the Tisch website.

At the gala, both Amy Schumer and Paul Shaffer were present to show their support for MS research. In an interview with People magazine, Amy revealed that her father struggles with MS. She explained, “Some days he’s really good and he’s with it and we’re joking around. And some days I go to visit my dad and it’s so painful. I can’t believe it.” Her experience watching her dad battle with MS inspired her to write and star in the movie TRAINWRECK, and also to get involved in supporting MS research. “If I can help at all I’m gonna try, even if that means I’ll get hurt,” she said.

Stem cells may help traumatic brain injuries (Kevin McCormack
Traumatic brain injury (TBI) is a huge problem in the US. According to the Centers for Disease Control and Prevention around 1.7 million Americans suffer a TBI every year; 250,000 of those are serious enough to result in a hospitalization; 52,000 are fatal. Even those who survive a TBI are often left with permanent disabilities, caused by swelling in the brain that destroys brain cells.

Now researchers at the University of Texas Health Science Center at Houston say using a person’s own stem cells could help reduce the severity of a TBI.

The study, published in the journal Stem Cells, found that taking stem cells from a person’s own bone marrow and then re-infusing them into the bloodstream, within 48 hours of the injury, can help reduce the swelling and inflammation that damages the brain.

In an interview with the Houston Chronicle Charles Cox, the lead researcher – and a member of CIRM’s Grants Working Group panel of experts – says the results are not a cure but they are encouraging:

charlescox

Charles Cox
(Drew Donovan / UTHealth)

“I’m talking about the difference between someone who recovers to the point that they can take care of themselves, and someone who is totally dependent on someone else for even simple tasks, like using the bathroom and bathing. That’s a dramatic difference.”

Schizophrenia: an imbalance of brain cell types?

Schizophrenia is a chronic mental disorder with a wide range of disabling symptoms such as delusional thoughts, hearing voices, anxiety and an inability to experience pleasure. It’s estimated that half of those with schizophrenia abuse drugs and alcohol, which likely contributes to increased incidence of unemployment, homelessness and suicide. No cure exists for the disorder because scientists don’t fully understand what causes it, and available treatments only mask the symptoms.

schizophrenia_art

A patient’s artistic representation of living with schizophrenia
(Wikipedia)

This week, researchers at the RIKEN Brain Science Institute in Japan reported new clues about what goes wrong at a cellular and molecular level in the brains of people with schizophrenia. The scientists created induced pluripotent stem cells (iPSCs) from healthy donors, as well as patients with schizophrenia, and then changed or specialized them into nerve cells, or neurons. They found that fewer iPSCs developed into neurons when comparing the cells from people with schizophrenia to the healthy donor cells. Instead, more iPSCs specialized into astrocytes, another type of brain cell. This fewer neurons/more astrocytes shift was also seen in brains of deceased donors who had schizophrenia.

Looking inside the cells, the researchers found higher levels of a protein called p38 in the neurons derived from the people with schizophrenia. Inhibiting the activity of p38 led to increased number of neurons and fewer astrocytes, which resembles the healthy state. These results, published in Translational Psychiatry and picked up by Health Canal, point to inhibitors of p38 activity as a potential path for developing new treatments.

Meeting the scientists who are turning their daughter’s cells into a research tool – one that could change her life forever

There’s nothing like a face-to-face meeting to really get to know someone. And when the life of someone you love is in the hands of that person, then it’s a meeting that comes packed with emotion and importance.

lilly-grossman

Lilly Grossman

Last week Gay and Steve Grossman got to meet the people who are working with their daughter Lilly’s stem cells. Lilly was born with a rare, debilitating condition called ADCY5-related dyskinesia. It’s an abnormal involuntary movement disorder caused by a genetic mutation that results in muscle weakness and severe pain. Because it is so rare, little research has been done on developing a deeper understanding of it, and even less on developing treatments.

buck-team

The Grossmans and Chris Waters meet the Buck team

 

That’s about to change. CIRM’s Induced Pluripotent Stem Cell  iPSC Bank – at the Buck Institute for Research on Aging – is now home to some of Lilly’s cells, and these are being turned into iPS cells for researchers to study the disease, and to hopefully develop and test new drugs or other therapies.

Gay said that meeting the people who are turning Lilly’s tissue sample into a research tool was wonderful:

“I think meeting the people who are doing the actual work at the lab is so imperative, and so important. I want them to see where their work is going and how they are not only affecting our lives and our daughter’s life but also the lives of the other kids who are affected by this rare disease and all rare diseases.”

Joining them for the trip to the Buck was Chris Waters, the driving force behind getting the Bank to accept new cell lines. Chris runs Rare Science a non-profit organization that focuses on children with rare diseases by partnering with patient family communities and foundations.

chris-gay-steve1

Steve and Gay Grossman and Chris Waters

In a news release, Chris says there are currently 7,000 identified rare diseases and 50 percent of those affect children; tragically 30 percent of those children die before their 5th birthday:

“The biggest gap in drug development is that we are not addressing the specific needs of children, especially those with rare diseases.  We need to focus on kids. They are our future. If it takes 14 years and $2 billion to get FDA approval for a new drug, how is that going to address the urgent need for a solution for the millions of children across the world with a rare disease? That’s why we created Rare Science. How do we help kids right now, how do we help the families? How do we make change?”

Jonathan Thomas, the Chair of the CIRM Board, said one way to help these families and drive change is by adding samples of stem cells from rare diseases like ADCY5 to the iPSC Bank:

“Just knowing the gene that causes a particular problem is only the beginning. By having the iPSCs of individuals, we can start to investigate the diseases of these kids in the labs. Deciphering the biology of why there are similarities and dissimilarities between these children could the open the door for life changing therapies.”

When CIRM launched the iPSC Initiative – working with CDI, Coriell, the Buck Institute and researchers around California – the goal was to build the largest iPSC Bank in the world.  Adding new lines, such as the cells from people with ADCY5, means the collection will be even more diverse than originally planned.

Chris hopes this action will serve as a model for other rare diseases, creating stem cell lines from them to help close the gap between discovery research and clinical impact. And she says seeing the people who are turning her idea into reality is just amazing:

“Oh my gosh. It’s just great to be here, to see all these people who are making this happen, they’re great. And I think they benefit too, by being able to put a human face on the diseases they are working on. I think you learn so much by meeting the patients and their families because they are the ones who are living with this every day. And by understanding it through their eyes, you can improve your research exponentially. It just makes so much more sense.”

bears

RARE Bears for RARE Science

To help raise funds for this work Rare Science is holding a special auction, starting tomorrow, of RARE Bears. These are bears that have been hand made by, and this is a real thing, “celebrity quilters”, so you know the quality is going to be amazing. All proceeds from the auction go to help RARE Science accelerate the search for treatments for the 200 million kids around the world who are undiagnosed or who have a rare disease.

 

How research on a rare disease turned into a faster way to make stem cells

Forest Gump. (Paramount Pictures)

Forest Gump. (Paramount Pictures)

If Forest Gump were a scientist, I’d like to think he would have said his iconic line a little differently. Dr. Gump would have said, “scientific research is like a box of chocolates – you never know what you’re gonna get.”

A new CIRM-funded study coming out of the Gladstone Institutes certainly proves this point. Published yesterday in the Proceedings of the National Academy of Sciences, the study found that a specific genetic mutation known to cause a rare disease called fibrodysplasia ossificans progressiva (FOP) makes it easier to reprogram adult skin cells into induced pluripotent stem cells (iPSCs).

Shinya Yamanaka received the Nobel Prize in medicine in 2012 for his seminal discovery of the iPSC technology, which enabled scientists to generate patient specific pluripotent stem cell lines from adult cells like skin and blood. These iPSC lines are useful for modeling disease in a dish, identifying new therapeutic drugs, and potentially for clinical applications in patients. However, one of the rate-limiting steps to this technology is the inefficient process of making iPSCs.

Yamanaka, a senior investigator at Gladstone, knows this problem all too well. In a Gladstone news release he commented, “inefficiency in creating iPSCs is a major roadblock toward applying this technology to biomedicine. Our study identified a surprising way to increase the number of iPSCs that we can generate.”

So how did Yamanaka and his colleagues discover this new trick for making iPSCs more efficiently? Originally, their intentions were to model a rare genetic disease called FOP. It’s commonly known as “stone man syndrome” because the disease converts normal muscle and connective tissue into bone either spontaneously or spurred by injury. Bone growth begins at a young age starting at the neck and progressively moving down the body. Because there is no treatment or cure, patients typically have a lifespan of only 40 years.

The Gladstone team wanted to understand this rare disease better by modeling it in a dish using iPSCs generated from patients with FOP. These patients had a genetic mutation in the ACVR1 gene, which plays an important role in the development of the embryo. FOP patients have a mutant form of ACVR1 that overstimulates this developmental pathway and boosts the activity of a protein called BMP (bone morphogenic protein). When BMP signaling is ramped up, they discovered that they could produce significantly more iPSCs from the skin cells of FOP patients compared to normal, healthy skin cells.

First author on the study, Yohei Hayashi, explained their hypothesis for why this mutation makes it easier to generate iPSCs:

“Originally, we wanted to establish a disease model for FOP that might help us understand how specific gene mutations affect bone formation. We were surprised to learn that cells from patients with FOP reprogrammed much more efficiently than cells from healthy patients. We think this may be because the same pathway that causes bone cells to proliferate also helps stem cells to regenerate.”

To be sure that enhanced BMP signaling caused by the ACVR1 mutation was the key to generating more iPSCs, they blocked this signal and discovered that much fewer iPSCs were made from FOP patient skin cells.

Senior Investigator Bruce Conklin, who was a co-author on this study, succinctly summarized the importance of their findings:

“This is the first reported case showing that a naturally occurring genetic mutation improves the efficiency of iPSC generation. Creating iPSCs from patient cells carrying genetic mutations is not only useful for disease modeling, but can also offer new insights into the reprogramming process.”

Gladstone investigators Bruce Conklin and Shinya Yamanaka. (Photo courtesy of Chris Goodfellow, Gladstone Institutes)

Gladstone investigators Bruce Conklin and Shinya Yamanaka. (Photo courtesy of Chris Goodfellow, Gladstone Institutes)

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.”

Eggciting News: Scientists developed fertilized eggs from mouse stem cells

A really eggciting science story came out early this week that’s received a lot of attention. Scientists in Japan reported in the journal Nature that they’ve generated egg cells from mouse stem cells, and these eggs could be fertilized and developed into living, breathing mice.

This is the first time that scientists have reported the successful development of egg cells in the lab outside of an animal. Many implications emerge from this research like gaining a better understanding of human development, generating egg cells from other types of mammals and even helping infertile women become pregnant.

Making eggs from pluripotent stem cells

The egg cells, also known as oocytes, were generated from mouse embryonic stem cells and induced pluripotent stem cells derived from mouse skin cells in a culture dish. Both stem cell types are pluripotent, meaning that they can generate almost any cell type in the human body.

After generating the egg cells, the scientists fertilized the eggs through in vitro fertilization (IVF) using sperm from a healthy male mouse. They allowed the fertilized eggs to grow into two cell embryos which they then transplanted into female mice. 11 out of 316 embryos (or 3.5%) produced offspring, which were then able to reproduce after they matured into adults.

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These mice were born from artificial eggs that were made from stem cells in a dish. (K. Hayashi, Kyushu University)

Not perfect science

While impressive, this study did identify major issues with its egg-making technique. First, less than 5% of the embryos made from the stem-cell derived eggs developed into viable mice. Second, the scientists discovered that some of their lab-grown eggs (~18%) had abnormal numbers of chromosomes – an event that can prevent an embryo from developing or can cause genetic disorders in offspring.

Lastly, to generate mature egg cells, the scientists had to add cells taken from mouse embryos in pregnant mice to the culture dish. These outside cells acted as a support environment that helped the egg cells mature and were essential for their development. The scientists are working around this issue by developing artificial reagents that could hopefully replace the need for these cells.

Egg cells made from embryonic stem cells in a dish. (K. Hayashi, Kyushu University)

Egg cells made from embryonic stem cells in a dish. (K. Hayashi, Kyushu University)

Will human eggs be next?

A big discovery such as this one immediately raises ethical questions and concerns about whether scientists will attempt to generate artificial human egg cells in a dish. Such technology would be extremely valuable to women who do not have eggs or have problems getting pregnant. However, in the wrong hands, a lot could go wrong with this technology including the creation of genetically abnormal embryos.

In a Nature news release, Azim Surani who is well known in this area of research, said that these ethical issues should be discussed now and include the general public. “This is the right time to involve the wider public in these discussions, long before and in case the procedure becomes feasible in humans.”

In an interview with Phys.org , James Adjaye, another expert from Heinrich Heine University in Germany, raised the point that even if we did generate artificial human eggs, “the final and ultimate test for fully functional human ‘eggs in a dish’ would be the fertilization using IVF, which is also ethically not allowed.”

Looking forward, senior author on the Nature study, Katsuhiko Hayashi, predicted that in a decade, lab-grown “oocyte-like” human eggs will be available but probably not at a scale for fertility treatments. Because of the technical issues his study revealed, he commented, “It is too preliminary to use artificial oocytes in the clinic.”

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.”

 

 

Using skin cells to repair damaged hearts

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Heart muscle  cells derived from skin cells

When someone has a heart attack, getting treatment quickly can mean the difference between life and death. Every minute delay in getting help means more heart cells die, and that can have profound consequences. One study found that heart attack patients who underwent surgery to re-open blocked arteries within 60 minutes of arriving in the emergency room had a six times greater survival rate than people who had to wait more than 90 minutes for the same treatment.

Clearly a quick intervention can be life-saving, which means an approach that uses a patient’s own stem cells to treat a heart attack won’t work. It simply takes too long to harvest the healthy heart cells, grow them in the lab, and re-inject them into the patient. By then the damage is done.

Now a new study shows that an off-the-shelf approach, using donor stem cells, might be the most effective way to go. Scientists at Shinshu University in Japan, used heart muscle stem cells from one monkey, to repair the damaged hearts of five other monkeys.

In the study, published in the journal Nature, the researchers took skin cells from a macaque monkey, turned those cells into induced pluripotent stem cells (iPSCs), and then turned those cells into cardiomyocytes or heart muscle cells. They then transplanted those cardiomyocytes into five other monkeys who had experienced an induced heart attack.

After 3 months the transplanted monkeys showed no signs of rejection and their hearts showed improved ability to contract, meaning they were pumping blood around the body more powerfully and efficiently than before they got the cardiomyocytes.

It’s an encouraging sign but it comes with a few caveats. One is that the monkeys used were all chosen to be as close a genetic match to the donor monkey as possible. This reduced the risk that the animals would reject the transplanted cells. But when it comes to treating people, it may not be feasible to have a wide selection of heart stem cell therapies on hand at every emergency room to make sure they are a good genetic match to the patient.

The second caveat is that all the transplanted monkeys experienced an increase in arrhythmias or irregular heartbeats. However, Yuji Shiba, one of the researchers, told the website ResearchGate that he didn’t think this was a serious issue:

“Ventricular arrhythmia was induced by the transplantation, typically within the first four weeks. However, this post-transplant arrhythmia seems to be transient and non-lethal. All five recipients of [the stem cells] survived without any abnormal behaviour for 12 weeks, even during the arrhythmia. So I think we can manage this side effect in clinic.”

Even with the caveats, this study demonstrates the potential for a donor-based stem cell therapy to treat heart attacks. This supports an approach already being tested by Capricor in a CIRM-funded clinical trial. In this trial the company is using donor cells, derived from heart stem cells, to treat patients who developed heart failure after a heart attack. In early studies the cells appear to reduce scar tissue on the heart, promote blood vessel growth and improve heart function.

The study from Japan shows the possibilities of using a ready-made stem cell approach to helping repair damage caused by a heart attacks. We’re hoping Capricor will take it from a possibility, and turn it into a reality.

If you would like to read some recent blog posts about Capricor go here and here.