UCLA scientists begin a journey to restore the sense of touch in paralyzed patients

Yesterday, CIRM-funded scientists at UCLA published an interesting study that sheds light on the development of sensory neurons, a type of nerve cell that is damaged in patients with spinal cord injury. Their early-stage findings could potentially, down the road, lead to the development of stem cell-based treatments that rebuild the sensory nervous system in paralyzed people that have lost their sense of touch.

Dr. Samantha Butler, a CIRM grantee and professor at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA, led the study, which was published in the journal eLife.

Restoring sensation

Butler and her team were interested in understanding the basic development of sensory interneurons in the spinal cord. These are nerve cells in the spinal cord that receive sensory signals from the environment outside the body (like heat, pain and touch) and relay these signals to the brain where the senses are then perceived.

Developing spinal cord injury treatments often focus on the loss of movement caused by damage to the motor neurons in the spine that control our muscles. However, the damage caused to sensory neurons in the spine can be just as debilitating to people with paralysis. Without being able to feel whether a surface is hot or cold, paralyzed patients can sustain serious burn injuries.

Butler commented in a UCLA news release that attempting to restoring sensation in paralyzed patients is just as important as restoring movement:

Samantha Butler

“The understanding of sensory interneuron development has lagged far behind that of another class of neurons—called motor neurons—which control the body’s ability to move. This lack in understanding belies the importance of sensation: it is at the core of human experience. Some patients faced with the reality of paralysis place the recovery of the sense of touch above movement.”

BMPs are important for sensory neuron development

To restore sensation in paralyzed patients, scientists need to replace the sensory neurons that are damaged in the spine. To create these neurons, Butler looked to proteins involved in the early development of the spinal cord called bone morphogenetic proteins or BMPs.

BMPs are an important family of signaling proteins that influence development of the embryo. Their signaling can determine the fate or identity of cells including cells that make up the developing spinal cord.

It was previously thought that the concentration of BMPs determined what type of sensory neuron a stem cell would develop into, but Butler’s team found the opposite in their research. By studying developing chick embryos, they discovered that the type, not the concentration, of BMP matters when determining what subtype of sensory neuron is produced. Increasing the amount of a particular BMP in the chick spinal cord only produced more of the same type of sensory interneuron rather than creating a different type.

Increasing the concentration of a certain type of BMP increases the production of the same categories of sensory interneurons (red and green). (Image credit: UCLA)

The scientists confirmed these findings using mouse embryonic stem cells grown in the lab. Interestingly a different set of BMPs were responsible for deciding sensory neuron fate in the mouse stem cell model compared to the chick embryo. But the finding that different BMPs determine sensory neuron identity was consistent.

So what and what’s next?

While this research is still in its early stages, the findings are important because they offer a better understanding of sensory neuron development in the spinal cord. This research also hints at the potential for stem cell-based therapies that replace or restore the function of sensory neurons in paralyzed patients.

Madeline Andrews, the first author of the study, concluded:

“Central nervous system injuries and diseases are particularly devastating because the brain and spinal cord are unable to regenerate. Replacing damaged tissue with sensory interneurons derived from stem cells is a promising therapeutic strategy. Our research, which provides key insights into how sensory interneurons naturally develop, gets us one step closer to that goal.”

The next stop on the team’s research journey is to understand how BMPs influence sensory neuron development in a human stem cell model. The UCLA news release gave a sneak preview of their plans in the coming years.

“Butler’s team now plans to apply their findings to human stem cells as well as drug testing platforms that target diseased sensory interneurons. They also hope to investigate the feasibility of using sensory interneurons in cellular replacement therapies that may one day restore sensation to paralyzed patients.”

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UCLA launches CIRM-funded clinical trial using engineered blood stem cells to treat skin cancer

It’s not uncommon for biomedical institutes as well as their funding partners to announce through press releases that a clinical trial they’re running has gotten off the ground and has started to enroll patients. For an outsider looking in, it may seem like they’re jumping the gun a bit. No patients have received the therapy. No cures have been declared. So why all the hubbub at the start?

The reality is this: the launch of a clinical trial isn’t a beginning. It represents many years of effort by many researchers and a lot of funding to take an idea and develop it into a tangible product that has been given clearance to be tested in people to potentially save their lives. That’s why this important milestone deserves to be recognized. So, we were excited to get the word out, in the form of a press release , that UCLA had announced this morning the launch of a CIRM-funded clinical trial testing a therapy for hard-to-treat cancers.

The UCLA clinical trial genetically alters a patient’s hematopoietic stem cells give rise to T cells that are efficient cancer killers.

It’s estimated that metastasis, or the spread of cancer to other parts of the body, is responsible for 90% of cancer deaths. Though radiation and chemotherapy treatments can stop a tumor in its tracks, a small population of cancer stem cells in the tumor lie dormant and can evade those anti-cancer approaches. Because of their unlimited potential to divide, the cancer stem cells regrow the tumor leading to its inevitable return and spread. Oncologists clearly need new approaches to help patients with this unmet medical need.

That’s where today’s clinical trial launch comes into the picture. Dr. Antonio Ribas, a member of the UCLA Broad Stem Cell Research Center, and his team have genetically engineered cancer-killing white blood cells called T cells and blood-forming stem cells collected from patients to produce a protein that, like a key in a lock, recognizes a protein found almost exclusively on the surface of many types of cancer. When the T cells are transfused back into the patient, they can more efficiently track down and eradicate hard-to-treat skin cancer stem cells. At the same, the transfused blood stem cells – which specialize into all the various immune system cells – provide a long-term supply of T cells for continued protection against reoccurrence of the tumor.

“Few options exist for the treatment of patients whose cancers have metastasized due to resistance to current therapies,” Ribas said in the UCLA press release. “This clinical trial will allow us to try a new approach that engineers the body’s immune system to fight metastasized tumors similar to how it fights germs and viruses.”

 

And as Dr. Maria Millan, CIRM’s President & CEO (interim), described in our accompanying press release, CIRM will be an ever-present partner to help Ribas’ team get the clinical trial smoothly out of the starting gate and provide the support needed to carry the therapy to its completion:

“This trial is the first step in developing a therapy that could alleviate the complications resulting from cancer metastases as well as potentially improving outcomes in cancer patients where there are currently no effective treatment options. We are confident that CIRM’s funding and partnership, in combination with the expertise provided by our Alpha Stem Cell Clinic network, will give provide critical support for the successful conduct of this important clinical trial.”

 

To learn more about this clinical trial, visit its page at clinicaltrials.gov. If you think you might be eligible to enroll, please contact Clinical Research Coordinator Justin Tran by email at justintran@mednet.ucla.edu or by phone at 310-206-2090.

Targeting hair follicle stem cells could be the key to fighting hair loss

Chia Pets make growing hair look easy. You might not be familiar with these chia plant terracotta figurines if you were born after the 80s, but I remember watching commercials growing up and desperately wanting a “Chia Pet, the pottery that grows!”

My parents eventually caved and got me a Chia teddy bear, and I was immediately impressed by how easy it was for my bear to grow “hair”. All I needed to do was to sprinkle water over the chia seeds and spread them over my chia pet, and in three weeks, voila, I had a bear that had sprouted a lush, thick coat of chia leaves.

These days, you can order Chia celebrities and even Chia politicians. If only treating hair loss in humans was as easy as growing sprouts on the top of Chia Mr. T’s head…

Activating Hair Follicle Stem Cells, the secret to hair growth?

That day might come sooner than we think thanks to a CIRM-funded study by UCLA scientists.

Published today in Nature Cell Biology, the UCLA team reported a new way to boost hair growth that could eventually translate into new treatments for hair loss. The study was spearheaded by senior authors Heather Christofk and William Lowry, both professors at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA.

Christofk and Lowry were interested in understanding the biology of hair follicle stem cells (HFSCs) and how their metabolism (the set of chemical changes required for a cell to sustain itself) plays a role in hair growth. HFSCs are adult stem cells that live in the hair follicles of our skin. They are typically inactive but can quickly “wake up” and actively divide when a new hair growth cycle is initiated. When HFSCs fail to activate, hair loss occurs.

A closer look at HFSCs in mice revealed that these stem cells are dependent on the products of the glycolytic pathway, a metabolic pathway that converts the nutrient glucose into a metabolite called pyruvate, to stimulate their activation. The HFSCs have a choice, they can either give the pyruvate to their mitochondria to produce more energy, or they can break down the pyruvate into another metabolite called lactate.

The scientists found that if they tipped the balance towards producing more lactate, the HFSCs activated and induced hair growth. On the other hand, if they blocked lactate production, HFSCs couldn’t activate and new hair growth was blocked.

In a UCLA news release, Lowry explained the novel findings of their study,

“Before this, no one knew that increasing or decreasing the lactate would have an effect on hair follicle stem cells. Once we saw how altering lactate production in the mice influenced hair growth, it led us to look for potential drugs that could be applied to the skin and have the same effect.”

New drugs for hair loss?

In the second half of the study, the UCLA team went on the hunt for drugs that promote lactate production in HFSCs in hopes of finding new treatment strategies to battle hair loss. They found two drugs that boosted lactate production when applied to the skin of mice. One was called RCGD423, which activates the JAK-Stat signaling pathway and stimulates lactate production. The other drug, UK5099, blocks the entry of pyruvate into the mitochondria, thereby forcing HFSCs to turn pyruvate into lactate resulting in hair growth. The use of both drugs for boosting hair growth are covered by provisional patent applications filed by the UCLA Technology Development Group.

Untreated mouse skin showing no hair growth (left) compared to mouse skin treated with the drug UK5099 (right) showing hair growth. Credit: UCLA Broad Stem Cell Center/Nature Cell Biology

Aimee Flores, the first author of the study, concluded by explaining why using drugs to target the HFSC metabolism is a promising approach for treating hair loss.

“Through this study, we gained a lot of interesting insight into new ways to activate stem cells. The idea of using drugs to stimulate hair growth through hair follicle stem cells is very promising given how many millions of people, both men and women, deal with hair loss. I think we’ve only just begun to understand the critical role metabolism plays in hair growth and stem cells in general; I’m looking forward to the potential application of these new findings for hair loss and beyond.”

If these hair growth drugs pan out, scientists might give Chia Pets a run for their money.

CIRM-funded life-saving stem cell therapy gets nod of approval from FDA

Cured_AR_2016_coverIf you have read our 2016 Annual Report (and if you haven’t you should, it’s brilliant) or just seen the cover you’ll know that it features very prominently a young girl named Evie Padilla Vaccaro.

Evie was born with Severe Combined Immunodeficiency or SCID – also known as “bubble baby disease”; we’ve written about it here. SCID is a rare but deadly immune disorder which leaves children unable to fight off simple infections. Many children with SCID die in the first few years of life.

Fortunately for Evie and her family, Dr. Don Kohn and his team at UCLA, working with a UK-based company called Orchard Therapeutics Ltd., have developed a treatment called OTL-101. This involves taking the patient’s own blood stem cells, genetically modifying them to correct the SCID mutation, and then returning the cells to the patient. Those modified cells create a new blood supply, and repair the child’s immune system.

Evie was treated with OTL-101 when she was a few months old. She is cured. And she isn’t the only one. To date more than 40 children have been treated with this method. All have survived and are doing well.

Orchard Therapeutics

 FDA acknowledgement

Because of that success the US Food and Drug Administration (FDA) has granted OTL-101 Rare Pediatric Disease Designation. This status is given to a treatment that targets a serious or life-threatening disease that affects less than 200,000 people, most of whom are under 18 years of age.

The importance of the Rare Pediatric Disease Designation is that it gives the company certain incentives for the therapy’s development, including priority review by the FDA. That means if it continues to show it is safe and effective it may have a faster route to being made more widely available to children in need.

In a news release Anne Dupraz, PhD, Orchard’s Chief Regulatory Officer, welcomed the decision:

“Together with Orphan Drug and Breakthrough Therapy Designations, this additional designation is another important development step for the OTL-101 clinical program. It reflects the potential of this gene therapy treatment to address the significant unmet medical need of children with ADA-SCID and eligibility for a Pediatric Disease Priority Review voucher at time of approval.”

Creating a trend

This is the second time in less than two weeks that a CIRM-funded therapy has been awarded Rare Pediatric Disease designation. Earlier this month Capricor Therapeutics was given that status for its treatment for Duchenne Muscular Dystrophy.

Two other CIRM-funded clinical trials – Humacyte and jCyte – have been given Regenerative Medicine Advanced Therapy Designation (RMAT) by the FDA. This makes them eligible for earlier and faster interactions with the FDA, and also means they may be able to apply for priority review and faster approval.

All these are encouraging signs for a couple of reasons. It suggests that the therapies are showing real promise in clinical trials. And it shows that the FDA is taking steps to encourage those therapies to advance as quickly – and safely of course – as possible.

Credit where credit is due

In the past we have been actively critical of the FDA’s sluggish pace in moving stem cell therapies out of the lab and into clinical trials where they can be tested in people. So when the FDA does show signs of changing the way it works it’s appropriate that that we are actively supportive.

Getting these designations is, of course, no guarantee the therapies will ultimately prove to be successful. But if they are, creating faster pathways means they can get to patients, the people who really need them, at a much faster pace.

 

 

 

 

 

World Sickle Cell Day: A View from the Front Line

June 19th is World Sickle Cell Day. Sickle cell disease is an inherited blood disorder that causes normally round red blood cells to take on an abnormal sickle shape, resulting in clogged arteries, severe pain, increased risk of stroke and reduced life expectancy. To mark the occasion we asked Nancy M. Rene to write a guest blog for us. Nancy is certainly qualified; she is the grandmother of a child with sickle cell disease, and the co-founder of Axis Advocacy, a non-profit advocating for those with sickle cell disease and their families.

Nancy ReneOn this World Sickle Cell Day, 2017, we can look back to the trailblazers in the fight against Sickle Cell Disease.  More than 40 years ago, the Black Panther Party established the People’s Free Medical Clinics in several cities across the country. One of the functions of these free clinics: to screen people for sickle cell disease and sickle cell trait. This life-saving screening began  in 1971.

Around that same time, President Richard Nixon allocated $10 million to begin the National Sickle Cell Anemia Control Act. This included counseling and screening, educational activities, and money for research.

In the early part of the twentieth century, most children with sickle cell died before their fifth birthday. With newborn screening available nationwide, the use of penicillin to prevent common infections, and the finding that hydroxyurea was useful in fighting the disease, life expectancy began to improve.

For much of the twentieth century, people with sickle cell disease felt that they were fighting the fight alone, knowledgeable doctors were scarce and insurance was often denied.

Making progress

As we moved into the twenty-first century, patients and families found they had some powerful allies. The National Institutes of Health (NIH), Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) joined the battle.  In 2016 the NIH held its tenth annual international conference on sickle cell disease that featured speakers from all over the world.  Participants were able to learn about best practices in Europe, Africa, India, and South America.

Sickle Cell centers at Howard University, the Foundation for Sickle Cell Disease Research, and other major universities across the country are pointing the way to the best that medicine has to offer.

Last year, the prestigious American Society of Hematology (ASH) launched an initiative to improve understanding and treatment of sickle cell disease.  Their four-point plan includes education, training, advocacy, and expanding its global reach.

Just last month, May 2017, the FDA looked at Endari, developed by Emmaus Medical in Torrance, California.  It is the first drug specifically developed for sickle cell disease to go through the FDA’s approval process. We should have a decision on whether or not the drug goes to market in July.

The progress that had been made up to the beginning of the twenty-first century was basically about alleviating the symptoms of the disease: the sickling, the organ damage and the pervasive anemia. But a cure was still elusive.

But in 2004, California’s Stem Cell Agency, CIRM, was created and it was as if the gates had opened.

Researchers had a new source of funding to enable  them to work on Sickle Cell Disease and many other chronic debilitating diseases at the cellular level. Scientists like Donald Kohn at UCLA, were able to research gene editing and find ways to use autologous bone marrow transplants to actually cure people with sickle cell. While some children with sickle cell have been cured with traditional bone marrow transplants, these transplants must come from a matched donor, and for most patients, a matched donor is simply not available. CIRM has provided the support needed so that researchers are closing in on the cure. They are able to share strategies with doctors and researchers throughout the world

And finally, support from the federal government came with the passage of the Affordable Care Act and adequate funding for the NIH, CDC, the Health Resources and Services Administration (HRSA), and FDA.

Going backwards

And yet, here we are, World Sickle Cell Day, 2017.

Will this be a case of one step forward two steps back?

Are we really going back to the time when people with Sickle Cell Disease could not get health insurance because sickle cell is a pre-existing condition, to the time when there was little money and no interest in research or professional training, to a time when patients and their families were fighting this fight alone?

For all of those with chronic disease, it’s as if we are living a very bad dream.

Time to wake up

For me, I want to wake up from that dream.  I want to look forward to a future where patients and families, where Joseph and Tiffany and Marissa and Ken and Marcus and all the others, will no longer have to worry about getting well-informed, professional treatment for their disease.

Where patients will no longer fear going to the Emergency Room

Where doctors and researchers have the funding they need to support them in their work toward the cure,

Where all children, those here in the United States along with those in Africa, India, and South America, will have access to treatments that can free them from pain and organ damage of sickle cell disease.

And where all people with this disease can be cured.

Latest space launch sends mice to test bone-building drug

Illustration of mice adapting to their custom-designed space habitat on board the International Space Station. Image courtesy of the Center for the Advancement of Science in Space

Astronauts on the International Space Station (ISS) received some furry guests this weekend with the launch of SpaceX’s Dragon supply capsule. On Saturday June 3rd, 40 mice were sent to the ISS along with other research experiments and medical equipment. Scientists will be treating the mice with a bone-building drug in search of a new therapy to combat osteoporosis, a disease that weakens bones and affects over 200 million people globally.

The bone-building therapy comes out of CIRM-funded research by UCLA scientists Dr. Chia Soo, Dr. Kang Ting and Dr. Ben Wu. Back in 2015, the UCLA team published that a protein called NELL-1 stimulates bone-forming stem cells, known as mesenchymal stem cells, to generate new bone tissue more efficiently in mice. They also found that NELL-1 blocked the function of osteoclasts – cellular recycling machines that break down and absorb bone – thus increasing bone density in mice.

Encouraged by their pre-clinical studies, the team decided to take their experiments into space. In collaboration with NASA and a grant from the Center for the Advancement of Science in Space (CASIS), they made plans to test NELL-1’s effects on bone density in an environment where bone loss is rapidly accelerated due to microgravity conditions.

Bone loss is a major concern for astronauts living in space for extended periods of time. The earth’s gravity puts pressure on our bones, stimulating bone-forming cells called osteoblasts to create new bone. Without gravity, osteoblasts stop functioning while the rate of bone resorption increases by approximately 1.5% per month. This translates to almost a 10% loss in bone density for every 6 months in space.

In a UCLA news release, Dr. Wu explained how they modified the NELL-1 treatment to stand up to the tests of space:

“To prepare for the space project and eventual clinical use, we chemically modified NELL-1 to stay active longer. We also engineered the NELL-1 protein with a special molecule that binds to bone, so the molecule directs NELL-1 to its correct target, similar to how a homing device directs a missile.”

The 40 mice will receive NELL-1 injections for four weeks on the ISS, at which point, half of the mice will be sent back to earth to receive another four weeks of NELL-1 treatment. The other half will stay in space and receive the same treatment so the scientists can compare the effects of NELL-1 in space and on land.

The Rodent Research Hardware System includes three modules: Habitat, Transporter, and Animal Access Unit.
Credits: NASA/Dominic Hart

The UCLA researchers hope that NELL-1 will prevent bone loss in the space mice and could lead to a new treatment for bone loss or bone injury in humans. Dr. Soo explained in an interview with SpaceFlight Now,

“We are hoping this study will give us some insights on how NELL-1 can work under these extreme conditions and if it can work for treating microgravity-related bone loss, which is a very accelerated, severe form of bone loss, then perhaps it can (be used) for patients one day on Earth who have bone loss due to trauma or due to aging or disease.”

If you want to learn more about this study, watch this short video below provided by UCLA. 

Stem cell stories that caught our eye: better ovarian cancer drugs, creating inner ear tissue, small fish big splash

Two drugs are better than one for ovarian cancer (Karen Ring). Earlier this week, scientists from UCLA reported that a combination drug therapy could be an effective treatment for 50% of aggressive ovarian cancers. The study was published in the journal Precision Oncology and was led by Dr. Sanaz Memarzadeh.

Women with high-grade ovarian tumors have an 85% chance of tumor recurrence after treatment with a common chemotherapy drug called carboplatin. The UCLA team found in a previous study that ovarian cancer stem cells are to blame because they are resistant to carboplatin. It’s because these stem cells have an abundance of proteins called cIAPs, which prevent cell death from chemotherapy.

Ovarian+cancer+tumor+cells_mid

Ovarian cancer cells (blue) expressing cIAP protein (red) on the left are more sensitive to a combination therapy than cancer cells that don’t express the protein on the right. (UCLA Broad Stem Cell Research Center/Precision Oncology)

Memarzadeh discovered that an experimental drug called birinapant made some ovarian cancer tumors more sensitive to chemotherapy treatment by breaking down cIAPs. This gave her the idea that combining the two drugs, birinapant and carboplatin, might be a more effective strategy for treating aggressive ovarian tumors.

By treating with the two drugs simultaneously, the scientists improved the survival rate of mice with ovarian cancer. They also tested this combo drug treatment on 23 ovarian cancer cell lines derived from women with highly aggressive tumors. The treatment killed off half of the cell lines indicating that some forms of this cancer are resistant to the combination treatment.

When they measured the levels of cIAPs in the human ovarian cancer cell lines, they found that high levels of the proteins were associated with ovarian tumor cells that responded well to the combination treatment. This is exciting because it means that clinicians can analyze tumor biopsies for cIAP levels to determine whether certain ovarian tumors would respond well to combination therapy.

Memarzadeh shared her plans for future research in a UCLA news release,

“I believe that our research potentially points to a new treatment option. In the near future, I hope to initiate a phase 1/2 clinical trial for women with ovarian cancer tumors predicted to benefit from this combination therapy.”

In a first, researchers create inner ear tissue. From heart muscle to brain cells to insulin-producing cells, researchers have figured out how to make a long list of different human cell types using induced pluripotent stem cells (iPSCs) – cells taken from the body and reprogrammed into a stem cell-like state.

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Human inner ear organoid with sensory hair cells (cyan) and sensory neurons (yellow). An antibody for the protein CTBP2 reveals cell nuclei as well as synapses between hair cells and neurons (magenta). | Photo: Karl Koehler

This week, a research group at the Indiana University School of Medicine successfully added inner ear cells to that list. This feat, published in Nature Biotechnology, is especially important given the fact that the inner ear is one of the few parts of the body that cannot be biopsied for further examination. With these cells in hands, new insights into the causes of hearing loss and balance disorders may be on the horizon.

The inner ear contains 75,000 sensory hair cells that convert sound waves into electrical signals to the brain. Loud noises, drug toxicity, and genetic mutations can permanently damage the hair cells leading to hearing loss and dizziness. Over 15%  of the U.S. population have some form of hearing loss and that number swells to 67% for people over 75.

Due to the complex shape of the inner ear, the team grew the iPSCs into three dimensional balls of cells rather than growing them as a flat layer of cells on a petri dish. With educated guesses sprinkled in with some trial and error, the scientists, for the time, identified a recipe of proteins that stimulated the iPSCs to transform into inner ear tissue. And like any great recipe, it wasn’t so much the ingredient list but the timing that was key:

“If you apply these signals at the wrong time you can potentially generate a brain instead of an inner ear,” first author Dr. Karl Koehler said in an interview with Gizmodo. “The real breakthrough is that we figured out the exact timing to do each one of these [protein] treatments.”

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Senior author, Eri Hashino, Ph.D., and first author, Karl R. Koehler, Ph.D. Photo: Indiana University

Careful examination shows that the tissue, referred to as organoids, not only contained the sensory hair cells of the inner ear cell but also nerve cells, or neurons, that are responsible for relaying the sound waves to the brain. Koehler explained the importance of this result in a press release:

“We also found neurons, like those that transmit signals from the ear to the brain, forming connections with sensory cells. This is an exciting feature of these organoids because both cell types are critical for proper hearing and balance.”

Though it’s still early days, these iPSC-derived inner ear organoids are a key step toward the ultimate goal of repairing hearing loss. Senior author, Dr. Eri Hashino, talked about the team’s approach to reach that goal:

“Up until now, potential drugs or therapies have been tested on animal cells, which often behave differently from human cells. We hope to discover new drugs capable of helping regenerate the sound-sending hair cells in the inner ear of those who have severe hearing problems.”

This man’s research is no fish tale
And finally, we leave you this week with a cool article and video by STAT. It features Dr. Leonard Zon of Harvard University and his many, many tanks full of zebrafish. This little fish has made a huge splash in understanding human development and disease. But don’t take my word for it, watch the video!

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

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

New theory for how the nervous system develops.

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

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

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

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

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

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

A UCLA press release explained what the scientists discovered next,

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

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

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

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

Age could be written in our stem cells.

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

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

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

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

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

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

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

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

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

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

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

Identical twins not so identical (Todd Dubnicoff)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Cystinosis_Cherqui

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

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

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

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

Bye Bye bubble baby disease: promising results from stem cell gene therapy trial for SCID

Evangelina Padilla-Vaccaro
(Front cover of CIRM’s 2016 Annual Report)

You don’t need to analyze any data to know for yourself that Evangelina Vaccaro’s experimental stem cell therapy has cured her of a devastating, often fatal disease of the immune system. All you have to do is look at a photo or video of her to see that she’s now a happy, healthy 5-year-old with a full life ahead of her.

But a casual evaluation of one patient won’t get therapies approved in the U.S. by the Food and Drug Administration (FDA). Instead, a very careful collection of quantitative data from a series of clinical trial studies is a must to prove that a treatment is safe and effective. Each study’s results also provide valuable information on how to tweak the procedures to improve each follow on clinical trial.

A CIRM-funded clinical trial study published this week by a UCLA research team in the Journal of Clinical Investigation did just that. Of the ten participants in the trial, nine including Evangelina were cured of adenosine deaminase-deficient severe combined immunodeficiency, or ADA-SCID, a disease that is usually fatal within the first year of life if left untreated.

In the past, children with SCID were isolated in a germ-free sterile clear plastic bubbles, thus the name “bubble baby disease”. [Credit: Baylor College of Medicine Archives]

ADA-SCID, also referred to as bubble baby disease, is so lethal because it destroys the ability to fight off disease. Affected children have a mutation in the adenosine deaminase gene which, in early development, causes the death of cells that normally would give rise to the immune system. Without those cells, ADA-SCID babies are born without an effective immune system. Even the common cold can be fatal so they must be sheltered in clean environments with limited physical contact with family and friends and certainly no outdoor play.

A few treatments exist but they have limitations. The go-to treatment is a blood stem cell transplant (also known as a bone marrow transplant) from a sibling with matched blood. The problem is that a match isn’t always available and a less than perfect match can lead to serious, life-threatening complications. Another treatment called enzyme replacement therapy (ERT) involves a twice-weekly injection of the missing adenosine deaminase enzyme. This approach is not only expensive but its effectiveness in restoring the immune system varies over a lifetime.

Evangelina being treated by Don Kohn and his team in 2012.  Photo: UCLA

The current study led by Don Kohn, avoids donor cells and enzyme therapy altogether by fixing the mutation in the patient’s own cells. Blood stem cells are isolated from a bone marrow sample and taken back to the lab where a functional copy of the adenosine deaminase gene is inserted into the patient’s cells. When those cells are ready, the patient is subjected to drugs – the same type that are used in cancer therapy – that kill off a portion of the patient’s faulty immune system to provide space in the bone marrow. Then the repaired blood stem cells are transplanted back into the body where they settle into the bone marrow and give rise to a healthy new immune system.

The ten patients were treated between 2009 and 2012 and their health was followed up for at least four years. As of June 2016, nine of the patients in the trial – (all infants except for an eight-year old) – no longer need enzyme injections and have working immune systems that allow them to play outside, attend school and survive colds and other infections that inevitably get passed around the classroom. The tenth patient was fifteen years old at the time of the trial and their treatment was not effective suggesting that early intervention is important. No serious side effects were seen in any of the patients.

Evangelina V

Evangelina Vaccaro (far right), who received Dr. Kohn’s treatment for bubble baby disease in 2012, with her family before her first day of school. Photo: UCLA, courtesy of the Vaccaro family

Now, this isn’t the first ever stem cell gene therapy clinical trial to successfully treat ADA-SCID. Kohn’s team and others have carried out clinical trials over the past few decades, and this current study builds upon the insights of those previous results. In a 2014 press release reporting preliminary results of this week’s published journal article, Kohn described the importance of these follow-on clinical trials for ensuring the therapy’s success:

UCLA Jonsson Comprehensive Cancer Center
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Don Kohn

“We were very happy that over the course of several clinical trials and after making refinements and improvements to the treatment protocol, we are now able to provide a cure for babies with this devastating disease using the child’s own cells.”

The team’s next step is getting FDA approval to use this treatment in all children with ADA-SCID. To reach this aim, the team is carrying out another clinical trial which will test a frozen preparation of the repaired blood stem cells. Being able to freeze the therapy product buys researchers more time to do a thorough set of safety tests on the cells before transplanting them into the patient. A frozen product is also much easier to transport for treating children who live far from the laboratories that perform the gene therapy. In November of last year, CIRM’s governing Board awarded Kohn’s team $20 million to support this project.

If everything goes as planned, this treatment will be the first stem cell gene therapy ever approved in the U.S. We look forward to adding many new photos next to Evangelina’s as more and more children are cured of ADA-SCID.