Have scientists discovered a natural way to boost muscle regeneration?

Painkillers like ibuprofen and aspirin are often a part of an athlete’s post-exercise regimen after intense workouts. Sore muscles, aches and stiffness can be more manageable by taking these drugs – collectively called non-steroidal anti-inflammatory drugs, or NSAIDS – to reduce inflammation and pain. But research suggests that the anti-inflammatory effects of these painkillers might cause more harm than good by preventing muscle repair and regeneration after injury or exercise.

A new study out of Stanford Medicine supports these findings and proposes that a component of the inflammatory process is necessary to promote muscle regeneration. Their study was funded in part by a CIRM grant and was published this week in the Proceedings of the National Academy of Sciences.

Muscle stem cells are scattered throughout skeletal muscle tissue and remain inactive until they are stimulated to divide. When muscles are damaged or injured, an inflammatory response involving a cascade of immune cells, molecules and growth factors activates these stem cells, prompting them to regenerate muscle tissue.

Andrew Ho, Helen Blau and Adelaida Palla led a study that found drugs like aspirin and ibuprofen can inhibit the ability of muscle tissue to repair itself in mice. (Image credit: Scott Reiff)

The Stanford team discovered that a molecule called Prostaglandin E2 or PGE2 is released during the inflammatory response and stimulates muscle repair by directly targeting the EP4 receptor on the surface of muscle stem cells. The interaction between PGE2 and EP4 causes muscle stem cells to divide and robustly regenerate muscle tissue.

Senior author on the study, Dr. Helen Blau, explained her team’s interest in PGE2-mediated muscle repair in a news release,

“Traditionally, inflammation has been considered a natural, but sometimes harmful, response to injury. But we wondered whether there might be a component in the pro-inflammatory signaling cascade that also stimulated muscle repair. We found that a single exposure to prostaglandin E2 has a profound effect on the proliferation of muscle stem cells in living animals. We postulated that we could enhance muscle regeneration by simply augmenting this natural physiological process in existing stem cells already located along the muscle fiber.”

Further studies in mice revealed that injury increased PGE2 levels in muscle tissue and increased expression of the EP4 receptor on muscle stem cells. This gave the authors the idea that treating mice with a pulse of PGE2 could stimulate their muscle stem cells to regenerate muscle tissue.

Their hunch turned out to be right. Co-first author Dr. Adelaida Palla explained,

“When we gave mice a single shot of PGE2 directly to the muscle, it robustly affected muscle regeneration and even increased strength. Conversely, if we inhibited the ability of the muscle stem cells to respond to naturally produced PGE2 by blocking the expression of EP4 or by giving them a single dose of a nonsteroidal anti-inflammatory drug to suppress PGE2 production, the acquisition of strength was impeded.”

Their research not only adds more evidence against the using NSAID painkillers like ibuprofen and aspirin to treat sore muscles, but also suggests that PGE2 could be a natural therapeutic strategy to boost muscle regeneration.

This cross-section of regenerated muscle shows muscle stem cells (red) in their niche along the muscle fibers (green). (Photo courtesy of Blau lab)

PGE2 is already approved by the US Food and Drug Administration (FDA) to induce labor in pregnant women, and Dr. Blau hopes that further research in her lab will pave the way for repurposing PGE2 to treat muscle injury and other conditions.

“Our goal has always been to find regulators of human muscle stem cells that can be useful in regenerative medicine. It might be possible to repurpose this already FDA-approved drug for use in muscle. This could be a novel way to target existing stem cells in their native environment to help people with muscle injury or trauma, or even to combat natural aging.”

Baseball’s loss is CIRM’s gain as Stanford’s Linda Boxer is appointed to Stem Cell Agency Board

Boxer

Dr. Linda Boxer: Photo courtesy Stanford University

One of the things that fascinates me is finding out how people end up in the job they have, the job they love. It is rare that the direction they started out on is the one they end on. Usually, people take several different paths, some intended, some unintended, to get to where they want to be.

A case in point is Dr. Linda Boxer, a renowned and respected researcher and physician at the Stanford School of Medicine, and now the newest member of the CIRM Board (you can read all about that in our news release).

In Dr. Boxer’s case, her original career path was a million miles from working with California’s stem cell agency:

“The first career choice that I recall as a young child was professional baseball—growing up in Minnesota, I was a huge Twins fan—I did learn fairly quickly that this was not likely to be a career that was available for a girl, and it wasn’t clear what one did after that career ended at a relatively young age.”

Fortunately for us she became interested in science.

“I have always been curious about how things work—science classes in grade school were fascinating to me. I was given a chemistry kit as a birthday gift, and I was amazed at what happened when different chemicals were mixed together: color changes, precipitates forming, gas bubbles, explosions (small ones, of course).

Then when we studied biology in middle school, I was fascinated by what one could observe with a microscope and became very interested in trying to understand how living organisms work.

It was an easy decision to plan a career in science.  The tougher decision came in college when I had planned to apply to graduate school and earn a PhD, but I was also interested in human health and disease and thought that perhaps going to medical school made more sense.  Fortunately, one of my faculty advisors told me about combined MD/PhD programs, and that choice seemed perfect for me.”

Along the way she says she got a lot of help and support from her colleagues. Now she wants to do the same for others:

“Mentors are incredibly important at every career stage.  I have been fortunate to have been mentored by some dedicated scientists and physicians.  Interestingly, they have all been men.  There were really very few women available as mentors at the time—of course, that has changed for the better now.  It never occurred to me then that gender made a difference, and I just looked for mentors who had successful careers as scientists and physicians and who could provide advice to someone more junior.

One of the aspects of my role now that I enjoy the most is mentoring junior faculty and trainees.  I don’t think one can have too many mentors—different mentors can help with different aspects of one’s life and career.  I think it is very important for established scientists to give back and to help develop the next generation of physicians and scientists.”

Dr. Boxer is already well known to everyone at CIRM, having served as the “alternate” on the Board for Stanford’s Dr. Lloyd Minor. But her appointment by State Controller Betty Yee makes her the “official” Board member for Stanford. She brings a valuable perspective as both a scientist and a physician.

The Minnesota Twins lost out when she decided to pursue a career in science. We’re glad she did.

 

Stanford scientists devise an algorithm that identifies gene pairs associated with cancer

Using data from human tumor samples, Stanford scientists have developed a new computer algorithm to identify pairs of genes that cause cancer. Their research aims to identify alternative ways to target cancer-causing mutations that have thus far evaded effective clinical treatment.

The study, which was published this week in Nature Communications, was led by senior authors Dr. Ravi Majeti and Dr. David Dill and included two CIRM Bridges interns Damoun Torabi and David Cruz Hernandez.

Identifying Partners in Crime

Cancer cells are notorious for acquiring genetic mutations due to the instability of their genomes and errors in the machinery that repairs DNA. Sometimes these errors create what are called synthetic lethal genes. These are pairs of genes that can cause a cell to die if both genes are defective due to acquired mutations, but a defect in only one of the genes allows a cell to live.

Cancer cells rely on pairs of genes with similar functions for their survival. If one gene is mutated, then the cancer cell depends on the other functional gene, aka its “partner in crime”, to keep it doing its mischief. Scientist are interested in targeting this second partner gene in synthetic lethal pairs in the hopes of developing less toxic cancer therapies that only kill cancer cells instead of healthy ones too.

The Stanford team went on the hunt for synthetic lethal partner genes in data from 12 different human cancers using an algorithm they developed called Mining Synthetic Lethals (MiSL). David Dill explained their strategy in a Stanford Medicine news release:

“We were looking for situations in which, if gene A is mutated, gene Y is amplified to compensate for the loss of function of gene A. Conversely, gene Y is only ever deleted in cells in which gene A is not mutated.”

David Dill. (Credit: L.A. Cicero/Stanford News Service)

They identified a total of 3,120 cancer-causing mutations and over 145,000 potential synthetic lethal partner genes associated with these mutations. Some of these partnerships were identified in other studies, validating MiSL as an effective tool for their purposes, while other partnerships were novel.

Targeting Partners in Crime

One of the new partnerships they discovered was between a mutation in the IDH1 gene, which is associated with acute myeloid leukemia, and a gene called ACACA. The team validated this pair with experiments in the lab proving that defects in both IDH1 and ACACA blocked leukemia cell growth. MiSL identified 89 potential synthetic lethal partners for the leukemia-causing IDH1 mutation, 17 of which they believe could be targeted by existing cancer drugs.

The authors concluded that using computer algorithms to sift through mountains of biological data is a powerful strategy for identifying genetic relationships leveraged by tumors and could advance drug development for different types of cancers.

Ravi Majeti concluded,

“We’re entering a new era of precision health. Using data from real human tumors gives us important, fundamental advantages over using cancer cell lines that often don’t display the same mutation profiles. We’ve found that, although many known cancer-associated mutations are difficult to target clinically, their synthetic lethal partners may be much more druggable.”

Ravi Majeti (Credit: Steve Fisch)

Keeping intestinal stem cells in their prime

Gut stem cells (green) in the small intestine of a mouse.

The average length of the human gut is 25 feet long. That’s equivalent to four really tall people or five really short people lined up head to toe. Intestinal stem cells have the fun job of regenerating and replacing ALL the cells that line the gut. Therefore, it’s important for these stem cells to be able to self-renew, a process that replenishes the stem cell population. If this important biological process is disrupted, the intestine is at risk for diseases like inflammatory bowel disease and cancer.

This week, Stanford Medicine researchers published new findings about the biological processes responsible for regulating the regenerative capacity of intestinal stem cells. Their work, which was partially funded by CIRM, was published in the journal Nature.

Priming gut stem cells to self-renew

Scientists know that the self-renewal of intestinal stem cells is very important for a happy, functioning gut, but the nuances of what molecules and signaling pathways regulate this process have yet to be figured out. The Stanford team, led by senior author and Stanford Professor Dr. Calvin Kuo, studied two signaling pathways, Wnt and R-Spondin, that are involved in the self-renewal of intestinal stem cells in mice.

Dr. Calvin Kuo, Stanford Medicine.

“The cascade of events comprising the Wnt signaling pathway is crucial to stem cell self-renewal,” Dr. Kuo explained in an email exchange. “The Wnt pathway can be induced by either hormones classified as “Wnts” or “R-spondins”.  However, it is not known if Wnts or R-spondins cooperate to induce Wnt signaling, and if these Wnts and R-spondins have distinct functions or if they can mutually substitute for each other.   We explored how Wnts and R-spondins might cooperate to regulate intestinal stem cells – which are extremely active and regenerate the 25-foot lining of the human intestine every week.”

The team used different reagents to activate or block Wnt or R-spondin signaling and monitored the effects on intestinal stem cells. They found that both were important for the self-renewal of intestinal stem cells, but that they played different roles.

“Our work revealed that Wnts and R-spondins are not equivalent and that they have very distinct functions even though they both trigger the Wnt signaling cascade,” said Dr. Kuo. “Both Wnts and R-spondins are required to maintain intestinal stem cells.  However, Wnts perform more of a subservient “priming” function, where they prepare intestinal stem cells for the action of R-spondin, which is the active catalyst for inducing intestinal stem cells to divide.”

The authors believe that this multi-step regulation, involving priming and self-renewal factors could apply to stem cell systems in other organs and tissues in the body. Some of the researchers on this study including Dr. Kuo are pursuing this idea through a new company called Surrozen, which produces artificial bioengineered Wnt molecules that don’t require activation like natural Wnt molecules. These Wnt molecules were used in the current study and are explained in more detail in a separate Nature article published at the same time.

The company believes that artificial Wnts will be useful for understanding stem cell biology and potentially for therapeutic applications. Dr. Kuo explained,

“The new surrogate Wnts are easily produced and can circulate in the bloodstream, unlike natural Wnts.  There may be medical applications of these bioengineered Wnt surrogates in stimulating various stem cell compartments of the body, given the wide range of stem cells that are governed by natural Wnts.”

Stem cell-derived, 3D brain tissue reveals autism insights

Studying human brain disorders is one of the most challenging fields in biomedical research. Besides the fact that the brain is incredibly complex, it’s just plain difficult to peer into it.

It’s neither practical nor ethical to access the cells of the adult brain. Patrick J. Lynch, medical illustrator; C. Carl Jaffe, MD, cardiologist.

For one thing, it’s not practical, let alone ethical, to drill into an affected person’s skull and collect brain cells to learn about their disease. Another issue is that the faulty cellular and molecular events that cause brain disorders are, in many cases, thought to trace back to fetal brain development before a person is even born. So, just like a detective looking for evidence at the scene of a crime, neurobiologists can only piece together clues after the disease has already occurred.

The good news is these limitations are falling away thanks to human induced pluripotent stem cells (iPSCs), which are generated from an individual’s easily accessible skin cells. Last week’s CIRM-funded research report out of Stanford University is a great example of how this method is providing new human brain insights.

Using brain tissue grown from patient-derived iPSCs, Dr. Sergiu Pasca and his team recreated the types of nerve cell circuits that form during the late stages of pregnancy in the fetal cerebral cortex, the outer layer of the brain that is responsible for functions including memory, language and emotion. With this system, they observed irregularities in the assembly of brain circuitry that provide new insights into the cellular and molecular causes of neuropsychiatric disorders like autism.

Recreating interactions between different regions of the development from skin-derived iPSCs
Image: Sergui Pasca Lab, Stanford University

Holy Brain Balls! Recreating the regions of our brain with skin cells
Two years ago, Pasca’s group figured out a way grow iPSCs into tiny, three-dimensional balls of cells that mimic the anatomy of the cerebral cortex. The team showed that these brain spheres contain the expected type of nerve cells, or neurons, as well as other cells that support neuron function.

Still, the complete formation of the cortex’s neuron circuits requires connections with another type of neuron that lies in a separate region of the brain. These other neurons travel large distances in a developing fetus’ brain over several months to reach the cortical cortex. Once in place, these migrating neurons have an inhibitory role and can block the cortical cortex nerve signals. Turning off a nerve signal is just as important as turning one on. In fact, imbalances in these opposing on and off nerve signals are suspected to play a role in epilepsy and autism.

So, in the current Nature study, Pasca’s team devised two different iPSC-derived brain sphere recipes: one that mimics the neurons found in the cortical cortex and another that mimics the region that contains the inhibitory neurons. Then the researchers placed the two types of spheres in the same lab dish and within three days, they spontaneously fused together.

Under video microscopy, the migration of the inhibitory neurons into the cortical cortex was observed. In cells derived from healthy donors, the migration pattern of inhibitory neurons looked like a herky-jerkey car being driven by a student driver: the neurons would move toward the cortical cortex sphere but suddenly stop for a while and then start their migration again.

“We’ve never been able to recapitulate these human-brain developmental events in a dish before,” said Pasca in a press release, “the process happens in the second half of pregnancy, so viewing it live is challenging. Our method lets us see the entire movie, not just snapshots.”

New insights into Timothy Syndrome may also uncover molecular basis of autism
To study the migration of the inhibitory neurons in the context of a neuropsychiatric disease, iPSCs were generated from skin samples of patients with Timothy syndrome, a rare genetic disease which carries a wide-range of symptoms including autism as well as heart defects.

The formation of brain spheres from the patient-derived iPSCs proceeded normally. But the next part of the experiment revealed an abnormal migration pattern of the neurons.  The microscopy movies showed that the start and stop behavior of neurons happened more frequently but the speed of the migration slowed. The fascinating video below shows the differences in the migration patterns of a healthy (top) versus a Timothy sydrome-derived neuron (bottom). The end result was a disruption of the typically well-organized neuron circuitry.

Now, the gene that’s mutated in Timothy Syndrome is responsible for the production of a protein that helps shuttle calcium in and out of neurons. The flow of calcium is critical for many cell functions and adding drugs that slow down this calcium flux restored the migration pattern of the neurons. So, the researchers can now zero in their studies on this direct link between the disease-causing mutation and a specific breakdown in neuron function.

The exciting possibility is that, because this system is generated from a patient’s skin cells, experiments could be run to precisely understand each individual’s neuropsychiatric disorder. Pasca is eager to see what new insights lie ahead:

“Our method of assembling and carefully characterizing neuronal circuits in a dish is opening up new windows through which we can view the normal development of the fetal human brain. More importantly, it will help us see how this goes awry in individual patients.”

Could revving up stem cells help senior citizens heal as fast as high school seniors?

All physicians, especially surgeons, sport medicine doctors, and military medical corps share a similar wish: to able to speed up the healing process for their patients’ incisions and injuries. Data published this week in Cell Reports may one day fulfill that wish. The study – reported by a Stanford University research team – pinpoints a single protein that revs up stem cells in the body, enabling them to repair tissue at a quicker rate.

Screen Shot 2017-04-19 at 5.37.38 PM

Muscle fibers (dark areas surrounding by green circles) are larger in mice injected with HGFA protein (right panel) compared to untreated mice (left panel), an indication of faster healing after muscle injury.
(Image: Cell Reports 19 (3) p. 479-486, fig 3C)

Most of the time, adult stem cells in the body keep to themselves and rarely divide. This calmness helps preserve this important, small pool of cells and avoids unnecessary mutations that may happen whenever DNA is copied during cell division.

To respond to injury, stem cells must be primed by dividing one time, which is a very slow process and can take several days. Once in this “alert” state, the stem cells are poised to start dividing much faster and help repair damaged tissue. The Stanford team, led by Dr. Thomas Rando, aimed to track down the signals that are responsible for this priming process with the hope of developing drugs that could help jump-start the healing process.

Super healing serum: it’s not just in video games
The team collected blood serum from mice two days after the animals had been subjected to a muscle injury (the mice were placed under anesthesia during the procedure and given pain medication afterwards). When that “injured” blood was injected into a different set of mice, their muscle stem cells became primed much faster than mice injected with “uninjured” blood.

“Clearly, blood from the injured animal contains a factor that alerts the stem cells,” said Rando in a press release. “We wanted to know, what is it in the blood that is doing this?”

 

A deeper examination of the priming process zeroed in on a muscle stem cell signal that is turned on by a protein in the blood called hepatocyte growth factor (HGF). So, it seemed likely that HGF was the protein that they had been looking for. But, to their surprise, there were no differences in the amount of HGF found in blood from injured and uninjured mice.

HGFA: the holy grail of healing?
It turns out, though, that HGF must first be chopped in two by an enzyme called HGFA to become active. When the team went back and examined the injured and uninjured blood, they found that it was HGFA which showed a difference: it was more active in the injured blood.

To show that HGFA was directly involved in stimulating tissue repair, the team injected mice with the enzyme two days before the muscle injury procedure. Twenty days post injury, the mice injected with HGFA had regenerated larger muscle fibers compared to untreated mice. Even more telling, nine days after the HGFA treatment, the mice had better recovery in terms of their wheel running activity compared to untreated mice.

To mimic tissue repair after a surgery incision, the team also looked at the impact of HGFA on skin wound healing. Like the muscle injury results, injecting animals with HGFA two days before creating a skin injury led to better wound healing compared to untreated mice. Even the hair that had been shaved at the surgical site grew back faster. First author Dr. Joseph Rodgers, now at USC, summed up the clinical implications of these results :

“Our research shows that by priming the body before an injury you can speed the process of tissue repair and recovery, similar to how a vaccine prepares the body to fight infection. We believe this could be a therapeutic approach to improve recovery in situations where injuries can be anticipated, such as surgery, combat or sports.”

Could we help senior citizens heal as fast as high school seniors?
Another application for this therapeutic approach may be for the elderly. Lots of things slow down when you get older including your body’s ability to heal itself. This observation sparks an intriguing question for Rando:

“Stem cell activity diminishes with advancing age, and older people heal more slowly and less effectively than younger people. Might it be possible to restore youthful healing by activating this [HGFA] pathway? We’d love to find out.”

I bet a lot of people would love for you to find out, too.

Could the Answer to Treating Parkinson’s Disease Come From Within the Brain?

Sometimes a solution to a disease doesn’t come in the form of a drug or a stem cell therapy, but from within ourselves.

Yesterday, scientists from the Karolinska Institutet in Sweden reported an alternative strategy for treating Parkinson’s disease that involves reprogramming specific cells in the brain into the nerve cells killed off by the disease. Their method, which involves delivering reprogramming genes into brain cells called astrocytes, was able to alleviate motor symptoms associated with Parkinson’s disease in mice.

What is Parkinson’s Disease and how is it treated?

Parkinson’s disease (PD) is a progressive neurodegenerative disease that’s characterized by the death of dopamine-producing nerve cells (called dopaminergic neurons) in an area of the brain that controls movement.

Dopaminergic neurons grown in a culture dish. (Image courtesy of Faria Zafar, Parkinson’s Institute).

PD patients experience tremors in their hands, arms and legs, have trouble starting and stopping movement, struggle with maintaining balance and have issues with muscle stiffness. These troublesome symptoms are caused by a lack dopamine, a chemical made by dopaminergic neurons, which signals to the part of the brain that controls how a person initiates and coordinates movement.

Over 10 million people in the world are affected by PD and current therapies only treat the symptoms of the disease rather than prevent its progression. Many of these treatments involve drugs that replace the lost dopamine in the brain, but these drugs lose their effectiveness over time as the disease kills off more neurons, and they come with their own set of side effects.

Another strategy for treating Parkinson’s is replacing the lost dopaminergic neurons through cell-based therapies. However this research is still in its early stages and would require patients to undergo immunosuppressive therapy because the stem cell transplants would likely be allogeneic (from a donor) rather than autologous (from the same individual).

Drug and cell-based therapies both involve taking something outside the body and putting it in, hoping that it does the right thing and prevents the disease. But what about using what’s already inside the human body to fight off PD?

This brings us to today’s study where scientists reprogrammed brain cells in vivo (meaning inside a living organism) to produce dopamine in mice with symptoms that mimic Parkinson’s. Their method, which was published in the journal Nature Biotechnology, was successful in alleviating some of the Parkinson’s-related movement problems the mice had. This study was funded in part by a CIRM grant and received a healthy amount of coverage in the media including STATnews, San Diego Union-Tribune and Scientific American.

Reprogramming the brain to make more dopamine

Since Shinya Yamanaka published his seminal paper on reprogramming adult somatic cells into induced pluripotent stem cells, scientists have taken the building blocks of his technology a step further to reprogram one adult cell type into another. This process is called “direct reprogramming” or “transdifferentiation”. It involves delivering a specific cocktail of genes into cells that rewrite the cells identity, effectively turning them into the cell type desired.

The Karolinska team found that three genes: NEUROD1, ASCL1 and LMX1A combined with a microRNA miR218 were able to reprogram human astrocytes into induced dopaminergic neurons (iDANs) in a lab dish. These neurons looked and acted like the real thing and gave the scientists hope that this combination of factors could reprogram astrocytes into iDANs in the brain.

The next step was to test these factors in mice with Parkinson’s disease. These mice were treated with a drug that killed off their dopaminergic neurons giving them Parkinson’s-like symptoms. The team used viruses to deliver the reprogramming cocktail to astrocytes in the brain. After a few weeks, the scientists observed that some of the “infected” astrocytes developed into iDANs and these newly reprogrammed neurons functioned properly, and more importantly, helped reverse some of the motor symptoms observed in these mice.

This study offers a new potential way to treat Parkinson’s by reprogramming cells in the brain into the neurons that are lost to the disease. While this research is still in its infancy, the scientists plan to improve the safety of their technology so that it can eventually be tested in humans.

Bonus Blog Interview for World Parkinson’s Day

Ernest Arenas, Karolinska Institutet

In honor of World Parkinson’s day (April 11th), I’m providing a bonus blog interview about this research. I reached out to the senior author of this study, Dr. Ernest Arenas, to ask him a few more questions about his publication and the future studies his team is planning.

Q) What are the major findings of your current study and how do they advance research on Parkinson’s disease?

The current treatment for Parkinson’s disease (PD) is symptomatic and does not change the course of the disease. Cell replacement therapies, such as direct in vivo reprogramming of in situ [local] astrocytes into dopamine (DA) neurons, work by substituting the cells lost by disease and have the potential to halt or even reverse motor alterations in PD.

Q) Can you comment on the potential for gene therapy treatments for Parkinson’s patients?

We see direct in vivo reprogramming of brain astrocytes into dopamine neurons in situ as a possible future alternative to DA cell transplantation. This method represents a gene therapy approach to cell replacement since we use a virus to deliver four reprogramming factors. In this method, the donor cells are in the host brain and there is no need to search for donor cells and no cell transplantation or immunosuppression. The method for the moment is an experimental prototype and much more needs to be done in order to improve efficiency, safety and to translate it to humans.

Q) Will reprogrammed iDANs be susceptible to Parkinson’s disease over time?

As any other cell replacement therapy, the cells would be, in principle, susceptible to Parkinson’s disease. It has been found that PD catches up with transplanted cells in 15-20 years. We think that this is a sufficiently long therapeutic window.

In addition, direct in vivo reprogramming may also be performed with drug-inducible constructs that could be activated years after, as disease progresses. This might allow adding more cells by turning on the reprogramming factors with pharmacological treatment to the host. This was not tested in our study but the basic technology to develop such strategies currently exist.

Q) What are your plans for future studies and translating this research towards the clinic?

In our experiments, we used transgenic mice in order to test our approach and to ensure that we only reprogrammed astrocytes. There is a lot that still needs to be done in order to develop this approach as a therapy for Parkinson’s disease. This includes improving the efficiency and the safety of the method, as well as developing a strategy suitable for therapy in humans. This can be achieved by further improving the reprogramming cocktail, by using a virus with a selective tropism [affinity] for astrocytes and that do not incorporate the constructs into the DNA of the host cell, as well as using constructs with astrocyte-specific promoters and capable of self-regulating depending on the cell context.

Our study demonstrates for the first time that it is possible to use direct reprogramming of host brain cells in order to rescue neurological symptoms. These results indicate that direct reprogramming has the potential to become a novel therapeutic approach for Parkinson’s disease and opens new opportunities for the treatment of patients with neurological disorders.

CIRM-funded team uncovers novel function for protein linked to autism and schizophrenia

Imagine you’ve just stopped your car at the top of the steepest street in San Francisco. Now, if want to stay at the top of the hill you’re going to need to keep your foot on the brakes. Let go and you’ll start rolling down. Fast.

Don’t step off the brake pedal! Photo: Wikipedia

Conceptually, similar decision points happen in human development. A brain cell, for instance, has the DNA instructions to become any cell in the body but must “keep the brakes on”, or repress, genes responsible for other cell types. Release the silencing of those genes and the brain cell’s properties will get pulled toward other fates.

That’s the subject of a CIRM-funded research study published today in Nature which reports on the identification of a new type of repressor protein which opens up a new understanding of how brain cells establish and keep their identity. That may not sound so exciting to our non-scientist readers but this discovery could lead to new therapy approaches for neurological disorders like autism, schizophrenia, major depression and low I.Q.

Skin cells to brain cells with just three genes
In previous experiments, this Stanford University research team led by Marius Wernig, showed it’s possible to convert a skin cell to a brain cell, or neuron, by adding just three genes to the cells, including one called Myt1l. The other two genes were known to act as master “on switches” that activate a cascade of genes responsible for making neuron-specific proteins. Myt1l also helped increase the efficiency of this direct reprogramming but it’s exact role in the process wasn’t clear.

Direct conversion of skin cell into a neuron.
Image: Wernig Lab, Stanford

A closer examination of Myt1l protein function revealed that instead of being an on switch for neuron-specific genes, it was actually an off switch for skin-specific genes. Now, there’s nothing unusual about the existence of a protein that represses gene activity to help determine cell identity. But up until now, these repressors were thought to be “lineage specific” meaning they specifically switched off genes of a specific cell type. For example, a well-studied repressor called REST affects cell fate by putting the brakes on only nerve-specific genes. The case of Myt1l was different.

Many but one
The researchers found that, in brain cells, Myt1l not only blocked the activation of skin-specific genes, it also shut down genes related to lung, cartilage, heart and other cells fates. The one set of genes that Mytl1 repressor did not appear to act on was neuron-specific genes. From these results a “many but one” pattern emerged. That is; it seems Myt1l helps drive and maintain a neuron cell fate by shutting off gene networks for many different cell identities except for neurons. It’s a novel way to regulate cell fate, as Wernig explained in a press release:

Marius Wernig
Photo: Steve Fisch

“The concept of an inverse master regulator, one that represses many different developmental programs rather than activating a single program, is a unique way to control neuronal cell identity, and a completely new paradigm as to how cells maintain their cell fate throughout an organism’s lifetime.”

To build a stronger case for Myt1l function, the team looked at the effect of blocking the protein in the developing mouse brain. Sure enough, lifting Myt1l repression lead to a decrease in the number of neurons in the brain. Wernig described the impact of also inhibiting Myt1l in mature neurons:

“When this protein is missing, neural cells get a little confused. They become less efficient at transmitting nerve signals and begin to express genes associated with other cell fates.”

Potential cures can be uncovered withfundamental lab research
It turns out that Myt1l mutations have been recently found in people with autism, schizophrenia, major depression and low I.Q. Based on their new insights, the author suggest that in adults, these disorders may be caused by a neuron’s inability to maintain its identity rather than by a more permanent abnormality that occurred during fetal brain development. This hypothesis presents the exciting possibility of developing therapies that could improve symptoms.

Don’t Be Afraid: High school stem cell researcher on inspiring girls to pursue STEM careers

As part of our CIRM scholar blog series, we’re featuring the research and career accomplishments of CIRM funded students.

Shannon Larsuel

Shannon Larsuel is a high school senior at Mayfield Senior School in Pasadena California. Last summer, she participated in Stanford’s CIRM SPARK high school internship program and did stem cell research in a lab that studies leukemia, a type of blood cancer. Shannon is passionate about helping people through research and medicine and wants to become a pediatric oncologist. She is also dedicated to inspiring young girls to pursue STEM (Science, Technology, Engineering, and Mathematics) careers through a group called the Stem Sisterhood.

I spoke with Shannon to learn more about her involvement in the Stem Sisterhood and her experience in the CIRM SPARK program. Her interview is below.


Q: What is the Stem Sisterhood and how did you get involved?

SL: The Stem Sisterhood is a blog. But for me, it’s more than a blog. It’s a collective of women and scientists that are working to inspire other young scientists who are girls to get involved in the STEM field. I think it’s a wonderful idea because girls are underrepresented in STEM fields, and I think that this needs to change.

I got involved in the Stem Sisterhood because my friend Bridget Garrity is the founder. This past summer when I was at Stanford, I saw that she was doing research at Caltech. I reconnected with her and we started talking about our summer experiences working in labs. Then she asked me if I wanted to be involved in the Stem Sisterhood and be one of the faces on her website. She took an archival photo of Albert Einstein with a group of other scientists that’s on display at Caltech and recreated it with a bunch of young women who were involved in the STEM field. So I said yes to being in the photo, and I’m also in the midst of writing a blog post about my experience at Stanford in the SPARK program.

Members of The Stem Sisterhood

Q: What does the Stem Sisterhood do?

SL: Members of the team go to elementary schools and girl scout troop events and speak about science and STEM to the young girls. The goal is to inspire them to become interested in science and to teach them about different aspects of science that maybe are not that well known.

The Stem Sisterhood is based in Los Angeles. The founder Bridget wants to expand the group, but so far, she has only done local events because she is a senior in high school. The Stem Sisterhood has an Instagram account in addition to their blog. The blog is really interesting and features interviews with women who are in science and STEM careers.

Q: How has the Stem Sisterhood impacted your life?

SL: It has inspired me to reach out to younger girls more about science. It’s something that I am passionate about, and I’d like to pursue a career in the medical field. This group has given me an outlet to share that passion with others and to hopefully change the face of the STEM world.

Q: How did you find out about the CIRM SPARK program?

SL: I knew I wanted to do a science program over the summer, but I wasn’t sure what type. I didn’t know if I wanted to do research or be in a hospital. I googled science programs for high school seniors, and I saw the one at Stanford University. It looked interesting and Stanford is obviously a great institution. Coming from LA, I was nervous that I wouldn’t be able to get in because the program had said it was mostly directed towards students living in the Bay Area. But I got in and I was thrilled. So that’s basically how I heard about it, because I googled and found it.

Q: What was your SPARK experience like?

SL: My program was incredible. I was a little bit nervous and scared going into it because I was the only high school student in my lab. As a high school junior going into senior year, I was worried about being the youngest, and I knew the least about the material that everyone in the lab was researching. But my fears were quickly put aside when I got to the lab. Everyone was kind and helpful, and they were always willing to answer my questions. Overall it was really amazing to have my first lab experience be at Stanford doing research that’s going to potentially change the world.

Shannon working in the lab at Stanford.

I was in a lab that was using stem cells to characterize a type of leukemia. The lab is hoping to study leukemia in vitro and in vivo and potentially create different treatments and cures from this research. It was so cool knowing that I was doing research that was potentially helping to save lives. I also learned how to work with stem cells which was really exciting. Stem cells are a new advancement in the science world, so being able to work with them was incredible to me. So many students will never have that opportunity, and being only 17 at the time, it was amazing that I was working with actual stem cells.

I also liked that the Stanford SPARK program allowed me to see other aspects of the medical world. We did outreach programs in the Stanford community and helped out at the blood drive where we recruited people for the bone marrow registry. I never really knew anything about the registry, but after learning about it, it really interested me. I actually signed up for it when I turned 18. We also met with patients and their families and heard their stories about how stem cell transplants changed their lives. That was so inspiring to me.

Going into the program, I was pretty sure I wanted to be a pediatric oncologist, but after the program, I knew for sure that’s what I wanted to do. I never thought about the research side of pediatric oncology, I only thought about the treatment of patients. So the SPARK program showed me what laboratory research is like, and now that’s something I want to incorporate into my career as a pediatric oncologist.

I learned so much in such a short time period. Through SPARK, I was also able to connect with so many incredible, inspired young people. The students in my program and I still have a group chat, and we text each other about college and what’s new with our lives. It’s nice knowing that there are so many great people out there who share my interests and who are going to change the world.

Stanford SPARK students.

Q: What was your favorite part of the SPARK program?

SL: Being in the lab every day was really incredible to me. It was my first research experience and I was in charge of a semi-independent project where I would do bacterial transformations on my own and run the gels. It was cool that I could do these experiments on my own. I also really loved the end of the summer poster session where all the students from the different SPARK programs came together to present their research. Being in the Stanford program, I only knew the Stanford students, but there were so many other awesome projects that the other SPARK students were doing. I really enjoyed being able to connect with those students as well and learn about their projects.

Q: Why do you want to pursue pediatric oncology?

SL: I’ve always been interested in the medical field but I’ve had a couple of experiences that really inspired me to become a doctor. My friend has a charity that raises money for Children’s Hospital Los Angeles. Every year, we deliver toys to the hospital. The first year I participated, we went to the hospital’s oncology unit and something about it stuck with me. There was one little boy who was getting his chemotherapy treatment. He was probably two years old and he really inspired to create more effective treatments for him and other children.

I also participated in the STEAM Inquiry program at my high school, where I spent two years reading tons of peer reviewed research on immunotherapy for pediatric cancer. Immunotherapy is something that really interests me. It makes sense that since cancer is usually caused by your body’s own mutations, we should be able to use the body’s immune system that normally regulates this to try and cure cancer. This program really inspired me to go into this field to learn more about how we can really tailor the immune system to fight cancer.

Q: What advice do you have for young girls interested in STEM.

SL: My advice is don’t be afraid. I think that sometimes girls are expected to be interested in less intellectual careers. This perception can strike fear into girls and make them think “I won’t be good enough. I’m not smart enough for this.” This kind of thinking is not good at all. So I would say don’t be afraid and be willing to put yourself out there. I know for me, sometimes it’s scary to try something and know you could fail. But that’s the best way to learn. Girls need to know that they are capable of doing anything and if they just try, they will be surprised with what they can do.

Three people left blind by Florida clinic’s unproven stem cell therapy

Unproven treatment

Unproven stem cell treatments endanger patients: Photo courtesy Healthline

The report makes for chilling reading. Three women, all suffering from macular degeneration – the leading cause of vision loss in the US – went to a Florida clinic hoping that a stem cell therapy would save their eyesight. Instead, it caused all three to go blind.

The study, in the latest issue of the New England Journal of Medicine, is a warning to all patients about the dangers of getting unproven, unapproved stem cell therapies.

In this case, the clinic took fat and blood from the patient, put the samples through a centrifuge to concentrate the stem cells, mixed them together and then injected them into the back of the woman’s eyes. In each case they injected this mixture into both eyes.

Irreparable harm

Within days the women, who ranged in age from 72 to 88, began to experience severe side effects including bleeding in the eye, detached retinas, and vision loss. The women got expert treatment at specialist eye centers to try and undo the damage done by the clinic, but it was too late. They are now blind with little hope for regaining their eyesight.

In a news release Thomas Alibini, one of the lead authors of the study, says clinics like this prey on vulnerable people:

“There’s a lot of hope for stem cells, and these types of clinics appeal to patients desperate for care who hope that stem cells are going to be the answer, but in this case these women participated in a clinical enterprise that was off-the-charts dangerous.”

Warning signs

So what went wrong? The researchers say this clinic’s approach raised a number of “red flags”:

  • First there is almost no evidence that the fat/blood stem cell combination the clinic used could help repair the photoreceptor cells in the eye that are attacked in macular degeneration.
  • The clinic charged the women $5,000 for the procedure. Usually in FDA-approved trials the clinical trial sponsor will cover the cost of the therapy being tested.
  • Both eyes were injected at the same time. Most clinical trials would only treat one eye at a time and allow up to 30 days between patients to ensure the approach was safe.
  • Even though the treatment was listed on the clinicaltrials.gov website there is no evidence that this was part of a clinical trial, and certainly not one approved by the Food and Drug Administration (FDA) which regulates stem cell therapies.

As CIRM’s Abla Creasey told the San Francisco Chronicle’s Erin Allday, there is little evidence these fat stem cells are effective, or even safe, for eye conditions.

“There’s no doubt there are some stem cells in fat. As to whether they are the right cells to be put into the eye, that’s a different question. The misuse of stem cells in the wrong locations, using the wrong stem cells, is going to lead to bad outcomes.”

The study points out that not all projects listed on the Clinicaltrials.gov site are checked to make sure they are scientifically sound and have done the preclinical testing needed to reduce the likelihood they may endanger patients.

goldberg-jeffrey

Jeffrey Goldberg

Jeffrey Goldberg, a professor of Ophthalmology at Stanford and the co-author of the study, says this is a warning to all patients considering unproven stem cell therapies:

“There is a lot of very well-founded evidence for the positive potential of stem therapy for many human diseases, but there’s no excuse for not designing a trial properly and basing it on preclinical research.”

There are a number of resources available to people considering being part of a clinical trial including CIRM’s “So You Want to Participate in a Clinical Trial”  and the  website A Closer Look at Stem Cells , which is sponsored by the International Society for Stem Cell Research (ISSCR).

CIRM is currently funding two clinical trials aimed at helping people with vision loss. One is Dr. Mark Humayun’s research on macular degeneration – the same disease these women had – and the other is Dr. Henry Klassen’s research into retinitis pigmentosa. Both these projects have been approved by the FDA showing they have done all the testing required to try and ensure they are safe in people.

In the past this blog has been a vocal critic of the FDA and the lengthy and cumbersome approval process for stem cell clinical trials. We have, and still do, advocate for a more efficient process. But this study is a powerful reminder that we need safeguards to protect patients, that any therapy being tested in people needs to have undergone rigorous testing to reduce the likelihood it may endanger them.

These three women paid $5,000 for their treatment. But the final cost was far greater. We never want to see that happen to anyone ever again.