New findings about muscle stem cells reveals the potential for growing replacement organs

Chrissa Kioussi’s group at Oregon State University has made exciting advances in further unraveling the scientific mysteries of stem cells. In work detailed in Scientific Reports, this group found that muscle-specific stem cells actually have the ability to make multiple different cell types.

muscle_bicep_FaceBook_shutterstock_162592241

Pumping up our knowledge about muscle stem cells

Initially, this group was interested in understanding how gene expression changes during embryonic development of skeletal muscle. To understand this process, they labeled muscle stem cells with a kind of fluorescent dye, called GFP, which allowed them to isolate these cells at different stages of development.  Once isolated, they determined what genes were being expressed by RNA sequencing. Surprisingly, they found that in addition to genes involved in muscle formation, they also identified activation of genes involved in the blood, nervous, immune and skeletal systems.

This work is particularly exciting, because it suggests the existence of stem cell “pockets,” or stem cells that are capable of not only making a specific cell type, but an entire organ system.

In a press release, Dr. Kioussi said:

chrissa_kioussi

Chrissa Kioussi, PhD

“That cell populations can give rise to so many different cell types, we can use it at the development stage and allow it to become something else over time… We can identify these cells and be able to generate not one but four different organs from them — this is a prelude to making body parts in a lab.” 

This study is particularly exciting because it gives more credence to the idea that entire limbs can be reconstructed from a small group of stem cells. Such advances could have enormous meaning for individuals who have lost body parts due to amputation or disease.

Giving thanks to Caleb and all of our stem cell pioneers [Video]

For our last blog before the Thanksgiving holiday, we give thanks to the patients and their caregivers who are forging a path toward a new era of regenerative medicine therapies through their participation in CIRM-funded clinical trials.

Some of our trials are in the early stages which means they are mainly focused on safety. Participants go into these trials knowing that the cell therapy dose they receive will probably be too low to get any benefit for themselves. And in later trials, some patients will receive a placebo, or blank therapy, for comparison purposes. Even if a patient gets an effective dose, it may not work for them. So the decision to enroll in an experimental clinical trial is often a selfless act. Yet final approval of a therapy by the U.S. Food and Drug Administration (and other regulatory agencies around the world) depends on these brave souls and for that we are truly grateful.

So, with this Thanksgiving Day spirit in mind, we leave you with our latest video featuring Caleb Sizemore, a charming young man who epitomizes the courage of our clinical trial pioneers. At just 7 years old, Caleb was diagnosed with Duchenne Muscular Dystrophy (DMD), a degenerative muscle disease which makes it difficult for him to walk and climb stairs, has led to dangerous scarring of his heart muscle and carries a shortened life expectancy with most DMD patients not living past their 20s or 30s.

In a sit-down interview with us and in clips from his June 2017 presentation to the CIRM governing Board, Caleb talked about the impact of DMD on his life and his experience enrolling in Capricor Therapeutics’ CIRM-funded clinical trial. The trial is testing a stem cell therapy designed to repair the heart scarring that occurs with DMD. By the end of the three-minute video, I can assure you that you’ll be as captivated as we were by Caleb’s delightful, sincere and full-of-faith personality.

The life of a sleeping muscle stem cell is very busy

For biological processes, knowing when to slow down is as important as knowing when to step on the accelerator. Take for example muscle stem cells. In a healthy state, these cells mostly lay quiet and rarely divide but upon injury, they bolt into action by dividing and specializing into new muscle cells to help repair damaged muscle tissue. Once that mission is accomplished, the small pool of muscle stem cells is replenished through self-renewal before going back into a dormant, or quiescent, state.

muscle stem cell

Muscle stem cell (pink with green outline) sits along a muscle fiber. Image: Michael Rudnicki/OIRM

“Dormant” may not be the best way to describe it because a lot of activity is going on within the cells to maintain its sleepy state. And a better understanding of the processes at play in a dormant state could reveal insights about treating aging or diseased muscles which often suffer from a depletion of muscle stem cells. One way to analyze cellular activity is by examining RNA transcripts which are created when a gene is turned “on”. These transcripts are the messenger molecules that provide a gene’s instructions for making a particular protein.

By observing something, you change it
In order to carry out the RNA transcript analyses in animal studies, researchers must isolate and purify the stem cells from muscle tissue. The worry here is that all of the necessary poking of prodding of the cells during the isolation method will alter the RNA transcripts leading to a misinterpretation of what is actually happening in the native muscle tissue. To overcome this challenge, Dr. Thomas Rando and his team at Stanford University applied a recently developed technique that allowed them to tag and track the RNA transcripts within living mice.

The CIRM-funded study reported today in Cell Reports found that there are indeed significant differences in results when comparing the standard in vitro lab method to the newer in vivo method. As science writer Krista Conger summarized in a Stanford Medical School press release, those differences led to some unexpected results that hadn’t been observed previously:

“The researchers were particularly surprised to learn that many of the RNAs made by the muscle stem cells in vivo are either degraded before they are made into proteins, or they are made into proteins that are then rapidly destroyed — a seemingly shocking waste of energy for cells that spend most of their lives just cooling their heels along the muscle fiber.”

It takes a lot of energy to stay ready
Dr. Rando thinks that these curious observations do not point to an inefficient use of a cell’s resources but instead, “it’s possible that this is one way the cells stay ready to undergo a rapid transformation, either by blocking degradation of RNA or proteins or by swiftly initiating translation of already existing RNA transcripts.”

The new method provides Rando’s team a whole new perceptive on understanding what’s happening behind the scenes during a muscle stem cell’s “dormant” state. And Rando thinks the technique has applications well beyond this study:

Rando

Thomas Rando

“It’s so important to know what we are and are not modeling about the state of these cells in vivo. This study will have a big impact on how researchers in the field think about understanding the characteristics of stem cells as they exist in their native state in the tissue.”

 

 

Stem cell agency funds Phase 3 clinical trial for Lou Gehrig’s disease

ALS

At CIRM we don’t have a disease hierarchy list that we use to guide where our funding goes. We don’t rank a disease by how many people suffer from it, if it affects children or adults, or how painful it is. But if we did have that kind of hierarchy you can be sure that Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, would be high on that list.

ALS is a truly nasty disease. It attacks the neurons, the cells in our brain and spinal cord that tell our muscles what to do. As those cells are destroyed we lose our ability to walk, to swallow, to talk, and ultimately to breathe.

As Dr. Maria Millan, CIRM’s interim President and CEO, said in a news release, it’s a fast-moving disease:

“ALS is a devastating disease with an average life expectancy of less than five years, and individuals afflicted with this condition suffer an extreme loss in quality of life. CIRM’s mission is to accelerate stem cell treatments to patients with unmet medical needs and, in keeping with this mission, our objective is to find a treatment for patients ravaged by this neurological condition for which there is currently no cure.”

Having given several talks to ALS support groups around the state, I have had the privilege of meeting many people with ALS and their families. I have seen how quickly the disease works and the devastation it brings. I’m always left in awe by the courage and dignity with which people bear it.

BrainStorm

I thought of those people, those families, today, when our governing Board voted to invest $15.9 million in a Phase 3 clinical trial for ALS run by BrainStorm Cell Therapeutics. BrainStorm is using mesenchymal stem cells (MSCs) that are taken from the patient’s own bone marrow. This reduces the risk of the patient’s immune system fighting the therapy.

After being removed, the MSCs are then modified in the laboratory to  boost their production of neurotrophic factors, proteins which are known to help support and protect the cells destroyed by ALS. The therapy, called NurOwn, is then re-infused back into the patient.

In an earlier Phase 2 clinical trial, NurOwn showed that it was safe and well tolerated by patients. It also showed evidence that it can help stop, or even reverse  the progression of the disease over a six month period, compared to a placebo.

CIRM is already funding one clinical trial program focused on treating ALS – that’s the work of Dr. Clive Svendsen and his team at Cedars Sinai, you can read about that here. Being able to add a second project, one that is in a Phase 3 clinical trial – the last stage before, hopefully, getting approval from the Food and Drug Administration (FDA) for wider use – means we are one step closer to being able to offer people with ALS a treatment that can help them.

Diane Winokur, the CIRM Board Patient Advocate member for ALS, says this is something that has been a long time coming:

CIRM Board member and ALS Patient Advocate Diane Winokur

“I lost two sons to ALS.  When my youngest son was diagnosed, he was confident that I would find something to save him.  There was very little research being done for ALS and most of that was very limited in scope.  There was one drug that had been developed.  It was being released for compassionate use and was scheduled to be reviewed by the FDA in the near future.  I was able to get the drug for Douglas.  It didn’t really help him and it was ultimately not approved by the FDA.

When my older son was diagnosed five years later, he too was convinced I would find a therapy.  Again, I talked to everyone in the field, searched every related study, but could find nothing promising.

I am tenacious by nature, and after Hugh’s death, though tempted to give up, I renewed my search.  There were more people, labs, companies looking at neurodegenerative diseases.

These two trials that CIRM is now funding represent breakthrough moments for me and for everyone touched by ALS.  I feel that they are a promising beginning.  I wish it had happened sooner.  In a way, though, they have validated Douglas and Hugh’s faith in me.”

These therapies are not a cure for ALS. At least not yet. But what they will do is hopefully help buy people time, and give them a sense of hope. For a disease that leaves people desperately short of both time and hope, that would be a precious gift. And for people like Diane Winokur, who have fought so hard to find something to help their loved ones, it’s a vindication that those efforts have not been in vain.

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.”

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.

A horse, stem cells and an inspiring comeback story that may revolutionize tendon repair

Everyone loves a good comeback story. Probably because it leaves us feeling inspired and full of hope. But the comeback story about a horse named Dream Alliance may do more than that: his experience promises to help people with Achilles tendon injuries get fully healed and back on their feet more quickly.

Dream Alliance

Dream Alliance was bred and raised in a very poor Welsh town in the United Kingdom. One of the villagers had the dream of owning a thoroughbred racehorse. She convinced a group of her fellow townsfolk to pitch in $15 dollars a week to cover the costs of training the horse. Despite his lowly origins, Dream Alliance won his fourth race ever and his future looked bright. But during a race in 2008, one of his back hoofs cut a tendon in his front leg. The seemingly career-ending injury was so severe that the horse was nearly euthanized.

It works in horses, how about humans?
Instead, he received a novel stem cell procedure which healed the tendon and, incredibly, the thoroughbred went on to win the Welsh Grand National race 15 months later – one of the biggest races in the UK that is almost 4 miles long and involves jumping 22 fences. Researchers at the Royal Veterinary College in Liverpool developed the method and data gathered from the treatment of 1500 horses with this stem cell therapy show a 50% decrease in re-injury of the tendon.

It’s been so successful in horses that researchers at the University College of London and the Royal National Orthopaedic Hospital are currently running a clinical trial to test the procedure in humans.  Over the weekend, the Daily Mail ran a news story about the clinical trial. In it, team lead Andrew Goldberg explained how they got the human trial off the ground:

“Tendon injuries in horses are identical to those in humans, and using this evidence [from the 1500 treated horses] we were able to persuade the regulators to allow us to launch a small safety study in humans.”

Tendon repair: there’s got to be another way

Achilles tendon connects the calf muscle to the heel bone

The Achilles tendon is the largest tendon in the body and connects the calf muscle to the heel bone. It takes on a lot of strain during running and jumping so it’s a well-known injury to professional and recreational athletes but injuries also occur in those with a sedentary lifestyle. Altogether Achilles tendon injury occurs in about 5-10 people per 100,000. And about 25%-45% of those injuries require surgery which involves many months of crutches and it doesn’t always work. That’s why this stem cell approach is sorely needed.

The procedure is pretty straight forward as far as stem cell therapies go. Bone marrow from the patient’s hip is collected and mesenchymal stem cells – making up a small fraction of the marrow – are isolated. The stem cells are transferred to petri dishes and allowed to divide until there are several million cells. Then they are injected directly into the injured tendon.

A reason to be cautiously optimistic
Early results from the clinical trial are encouraging with a couple of the patients experiencing improvements. The Daily Mail article featured the clinical trial’s first patient who went from a very active lifestyle to one of excruciating ankle pain due to a gradually deteriorating Achilles tendon. Though hesitant when she first learned about the trial, the 46-year-old ultimately figured that the benefits outweighed the risk. That turned out to be a good decision:

“I worried, because no one had ever had it before, except a horse. But I was more worried I’d end up in a wheelchair. The difference now is amazing. I can do five miles on the treadmill without pain, and take my dog Honey on long walks again.”

The researchers aren’t exactly sure how the therapy works but mesenchymal stem cells are known to release factors that promote regeneration and reduce inflammation. The first patient’s positive results are just anecdotal at this point. The clinical trial is still recruiting volunteers so definitive results are still on the horizon. And even if that small trial is successful, larger clinical trials will be required to confirm effectiveness and safety. It will take time but without the careful gathering of this data, doctors and patients will remain in the dark about their chances for success with this stem cell treatment.

Hopefully the treatment proves to be successful and ushers in a golden era of comeback stories. Not just for star athletes eager to get back on the field but also for the average person whose career, good health and quality of life depends on their mobility.

Reducing animal testing with stem cells and electronic petri dishes

botoxThough the celebrities at Sunday’s Academy Awards worked hard to sport unique clothing and hair styles, I bet many had something in common: Botox injections. Botox, an FDA-approved, marketed form of Botulism neurotoxin, is well known for its wrinkle reducing effects. The neurotoxin’s other claim to fame is the fact that it’s the most lethal, naturally occurring poison known. Inhaling a minuscule amount – just 0.0000007 grams! – is enough to kill a 150 pound person.

Much smaller, non-lethal doses of Botulism neurotoxin are obviously used for its cosmetic application. It’s also used to treat a wide range of disorders including back pain, migraines and muscle spasms related to stroke and cerebral palsy. Because the toxin is produced naturally by the Clostridium botulinum bacteria, the amount of toxin can vary in each batch during the manufacturing process. So, it’s critical to carefully analyze the Botulism neurotoxin dose.  The standard test which has been around since the 1920’s is the mouse bioassay. During the test, increasing concentrations of the neurotoxin are injected into mice which are then observed for signs of paralysis (Botulism neurotoxin acts by blocking communication between nerves and muscle).

As you might expect, the lab mice suffer during the test, sometimes suffocating during the process. Because of the large market for these Botulism neurotoxin-based products, it’s estimated that about 600,000 laboratory mice in US and Europe are killed via the mouse bioassay each year. Though the media often portrays scientists as callous, cold-hearted people that couldn’t care less about the welfare of their lab animals, in reality, it’s just the opposite. Case in point: a research group at the University of Bern in Switzerland reported this week in Frontiers in Pharmacology that they have devised an alternative system that could help make this mouse bioassay obsolete.

mea2100_desc_mea

Multi-electrode assay petri dish. Credit: Multichannel Systems

To set up this new assay system, the researchers relied on mouse embryonic stem cells. The researchers added chemicals to the cells, stimulating them to transform into nerve cells, or neurons. These stem cell-derived neurons were placed in specialized petri dishes that look something like a computer chip. Wired with mini electrodes, the lab dishes allowed the continuous recording of electrical signals generated by the neurons. Adding small doses of Botox to the cells, the scientists could detect a shutdown of the neuron signaling which is the same underlying effect that causes paralysis in the mouse bioassay.

Print

Stem cell-derived neurons (green) grown on electrodes (outlined in white) allows monitoring of electrical nerve signals. Credit: Stephen Jenkinson, Institute for Infectious Diseases, University of Bern

This sensitive test could have applications beyond the detection of Botulism neurotoxin. The electrode dishes are easy to scale up and do not require highly trained staff. So, without the need for expensive animal testing, this system could be used as a high throughput drug screening platform to find other substances that have beneficial effects on neuron signaling.

Stem Cell Stories That Caught our Eye: Making blood and muscle from stem cells and helping students realize their “pluripotential”

Stem cells offer new drug for blood diseases. A new treatment for blood disorders might be in the works thanks to a stem cell-based study out of Harvard Medical School and Boston Children’s hospital. Their study was published in the journal Science Translational Medicine.

The teams made induced pluripotent stem cells (iPSCs) from the skin of patients with a rare blood disorder called Diamond-Blackfan anemia (DBA) – a bone marrow disease that prevents new blood cells from forming. iPSCs from DBA patients were then specialized into blood progenitor cells, the precursors to blood cells. However, these precursor cells were incapable of forming red blood cells in a dish like normal precursors do.

Red blood cells were successfully made via induced pluripotent stem cells from a Diamond-Blackfan anemia patient. Image: Daley lab, Boston Children’s

Red blood cells were successfully made via induced pluripotent stem cells from a Diamond-Blackfan anemia patient. Image: Daley lab, Boston Children’s

The blood progenitor cells from DBA patients were then used to screen a library of compounds to identify drugs that could get the DBA progenitor cells to develop into red blood cells. They found a compound called SMER28 that had this very effect on progenitor cells in a dish. When the compound was tested in zebrafish and mouse models of DBA, the researchers observed an increase in red blood cell production and a reduction of anemia symptoms.

Getting pluripotent stem cells like iPSCs to turn into blood progenitor cells and expand these cells into a population large enough for drug screening has not been an easy task for stem cell researchers.

Co-first author on the study, Sergei Doulatov, explained in a press release, “iPS cells have been hard to instruct when it comes to making blood. This is the first time iPS cells have been used to identify a drug to treat a blood disorder.”

In the future, the researchers will pursue the questions of why and how SMER28 boosts red blood cell generation. Further work will be done to determine whether this drug will be a useful treatment for DBA patients and other blood disorders.

 

Students realize their “pluripotential”. In last week’s stem cell stories, I gave a preview about an exciting stem cell “Day of Discovery” hosted by USC Stem Cell in southern California. The event happened this past Saturday. Over 500 local middle and high school students attended the event and participated in lab tours, poster sessions, and a career resource fair. Throughout the day, they were engaged by scientists and educators about stem cell science through interactive games, including the stem cell edition of Family Feud and a stem cell smartphone videogame developed by USC graduate students.

In a USC press release, Rohit Varma, dean of the Keck School of Medicine of USC, emphasized the importance of exposing young students to research and scientific careers.

“It was a true joy to welcome the middle and high school students from our neighboring communities in Boyle Heights, El Sereno, Lincoln Heights, the San Gabriel Valley and throughout Los Angeles. This bright young generation brings tremendous potential to their future pursuits in biotechnology and beyond.”

Maria Elena Kennedy, a consultant to the Bassett Unified School District, added, “The exposure to the Keck School of Medicine of USC is invaluable for the students. Our students come from a Title I School District, and they don’t often have the opportunity to come to a campus like the Keck School of Medicine.”

The day was a huge success with students posting photos of their experiences on social media and enthusiastically writing messages like “stem cells are our future” and “USC is my goal”. One high school student acknowledged the opportunity that this day offers to students, “California currently has biotechnology as the biggest growing sector. Right now, it’s really important that students are visiting labs and learning more about the industry, so they can potentially see where they’re going with their lives and careers.”

You can read more about USC’s Stem Cell Day of Discovery here. Below are a few pictures from the event courtesy of David Sprague and USC.

Students have fun with robots representing osteoblast and osteoclast cells at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

Students have fun with robots representing osteoblast and osteoclast cells at the USC Stem Cell Day of Discovery. Photo by David Sprague

Dr. Francesca Mariana shows off a mouse skeleton that has been dyed to show bones and cartilage at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

Dr. Francesca Mariana shows off a mouse skeleton that has been dyed to show bones and cartilage. Photo by David Sprague

USC masters student Shantae Thornton shows students how cells are held in long term cold storage tanks at -195 celsius at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

USC masters student Shantae Thornton shows students how cells are held in long term cold storage tanks at -195 celsius. Photo by David Sprague

Genesis Archila, left, and Jasmine Archila get their picture taken at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

Genesis Archila, left, and Jasmine Archila get their picture taken at the USC Stem Cell Day of Discovery. Photo by David Sprague

New stem cell recipes for making muscle: new inroads to study muscular dystrophy (Todd Dubnicoff)

Embryonic stem cells are amazing because scientists can change or specialize them into virtually any cell type. But it’s a lot easier said than done. Researchers essentially need to mimic the process of embryo development in a petri dish by adding the right combination of factors to the stem cells in just the right order at just the right time to obtain a desired type of cell.

Making human muscle tissue from embryonic stem cells has proven to be a challenge. The development of muscle, as well as cartilage and bone, are well characterized and known to form from an embryonic structure called a somite. Researches have even been successful working out the conditions for making somites from animal stem cells. But those recipes didn’t work well with human stem cells.

Now, a team of researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA has overcome this roadblock by carrying out a systematic approach using human tissue. As described in Cell Reports, the scientists isolated somites from early human embryos and studied their gene activity. By comparing somites that were just beginning to emerge with fully formed somites, the researchers pinpointed differences in gene activity patterns. With this data in hand, the team added factors to the cells that were known to affect the activity of those genes. Through some trial and error, they produced a recipe – different than those used in animal cells – that could convert 90 percent of the human stem cells into somites in only four days. Those somites could then readily transform into muscle or bone or cartilage.

This new method for making human muscle will be critical for the lab’s goal to develop therapies for Duchenne muscular dystrophy, an incurable muscle wasting disease that strikes young boys and is usually fatal by their 20’s.

The new protocol turned 90 percent of human pluripotent stem cells into somite cells in just four days; those somite cells then generated (left to right) cartilage, bone and muscle cells.  Image: April Pyle Lab/UCLA

The new protocol turned 90 percent of human pluripotent stem cells into somite cells in just four days; those somite cells then generated (left to right) cartilage, bone and muscle cells. Image: April Pyle Lab/UCLA

Scientists find new stem cell target for regenerating aging muscles

Young Arnold (wiki)

Young Arnold (wiki)

Today I’m going to use our former governor Arnold Schwarzenegger as an example of what happens to our muscles when we age.

One of Arnold’s many talents when he was younger was being a professional bodybuilder. As you can see in this photo, Arnold worked hard to generate an impressive amount of muscle that landed him lead roles in movies Conan the Barbarian and The Terminator.

Older Arnold

Older Arnold

If you look at pictures of Arnold now (who is now 68), while still being an impressively large human being, it’s obvious that much of his muscular bulk has diminished. That’s because as humans age, so do their muscles.

Muscles shrink with age

As muscles age, they slowly lose mass and shrink (a condition called sarcopenia) because of a number of reasons – one of them being their inability to regenerate new muscle tissue efficiently. The adult stem cells responsible for muscle regeneration are called satellite cells. When muscles are injured, satellite cells are activated to divide and generate new muscle fibers that can repair injury and also improve muscle function.

However, satellite cells become less efficient at doing their job over time because of environmental and internal reasons, and scientists are looking for new targets that can restore and promote the regenerative abilities of muscle stem cells for human therapeutic applications.

A study published earlier this week in Nature Medicine, identified a potential new target that could boost muscle stem cell regeneration and improved muscle function in a mouse model of Duchenne muscular dystrophy.

β1-integrin is important for muscle regeneration

Scientists from the Carnegie Institute of Washington found that β1-integrin is important for maintaining the homeostasis (or balance) of the muscle stem cell environment. If β1-integrin is doing its job properly, muscle stem cells are able to go about their regular routine of being dormant, activating in response to injury, dividing to create new muscle tissue, and then going back to sleep.

When the scientists studied the function of β1-integrin in the muscles of aged mice, they found that the integrin wasn’t functioning properly. Without β1-integrin, mouse satellite cells spontaneously turned into muscle tissue and were unable to maintain their regenerative capacity following muscle injury.

Upon further inspection, they found that β1-integrin interacts with a growth factor called fibroblast growth factor 2 (Fgf2) and this relationship was essential for promoting muscle regeneration following injury. When β1-integrin function deteriorates as in the muscles of aged mice, the mice lose sensitivity to the regenerative capacity of Fgf2.

Restoring muscle function in mice with muscular dystrophy

By using an antibody to artificially activate β1-integrin function in the muscles of aged mice, they were able to restore Fgf2 responsiveness and boosted muscle regeneration after injury. When a similar technique was used in mice with Duchenne muscular dystrophy, they observed muscle regeneration and improved muscle function.

Muscle loss seen in muscular dystrophy mice (left). Treatment with beta1 intern boosts muscle regeneration in the same mice (right). (Nature Medicine)

Muscle loss seen in muscular dystrophy mice (left). Treatment with B1-integrin boosts muscle regeneration in the same mice (right). (Nature Medicine)

The authors believe that β1-integrin acts as a sensor of the muscle stem cell environment that it maintains a balance between a dormant and a regenerative stem cell state. They conclude in their publication:

“β1-integrin senses the SC [satellite cell] niche to maintain responsiveness to Fgf2, and this integrin represents a potential therapeutic target for pathological conditions of the muscle in which the stem cell niche is compromised.”

Co-author on the study Dr. Chen-Ming Fan also spoke to the clinical relevance of their findings in a piece by GenBio:

“Inefficient muscular healing in the elderly is a significant clinical problem and therapeutic approaches are much needed, especially given the aging population. Finding a way to target muscle stem cells could greatly improve muscle renewal in older individuals.”

Does this mean anyone can be a body builder?

So does this study mean that one day we can prevent muscle loss in the elderly and all be body builders like Arnold? I highly doubt that. It’s important to remember these are preclinical studies done in mouse models and much work needs to be done to test whether β1-integrin is an appropriate therapeutic target in humans.

However, I do think this study sheds new light on the inner workings of the muscle stem cell environment. Finding out more clues about how to promote the health and regenerative function of this environment will bring the field closer to generating new treatments for patients suffering from muscle wasting diseases like muscular dystrophy.