The Spanish Inquisition and a tale of two stem cell agencies

Monty

Monty Python’s Spanish Inquisition sketch: Photo courtesy Daily Mail UK

It’s not often an article on stem cell research brings the old, but still much loved, British comedy series Monty Python into the discussion but a new study in the journal Cell Stem Cell does just that, comparing the impact of CIRM and the UK’s Regenerative Medicine Platform (UKRMP).

The article, written by Fiona Watt of King’s College London and Stanford’s Irv Weissman (a CIRM grantee – you can see his impressive research record here) looks at CIRM and UKRMP’s success in translating stem cell research into clinical applications in people.

It begins by saying that in research, as in real estate, location is key:

“One thing that is heavily influenced by location, however, is our source of funding. This in turn depends on the political climate of the country in which we work, as exemplified by research on stem cells.”

And, as Weissman and Watt note, political climate can have a big impact on that funding. CIRM was created by the voters of California in 2004, largely in response to President George W. Bush’s restrictions on the use of federal funds for embryonic stem cell research. UKRMP, in contrast was created by the UK government in 2013 and designed to help strengthen the UK’s translational research sector. CIRM was given $3 billion to do its work. UKRMP has approximately $38 million.

Inevitably the two agencies took very different approaches to funding, shaped in part by the circumstances of their birth – one as a largely independent state agency, the other created as a tool of national government.

CIRM, by virtue of its much larger funding was able to create world-class research facilities, attract top scientists to California and train a whole new generation of scientists. It has also been able to help some of the most promising projects get into clinical trials. UKRMP has used its more limited funding to create research hubs, focusing on areas such as cell behavior, differentiation and manufacturing, and safety and effectiveness. Those hubs are encouraged to work collaboratively, sharing their expertise and best practices.

Weissman and Watt touch on the problems both agencies ran into, including the difficulty of moving even the best research out of the lab and into clinical trials:

“Although CIRM has moved over 20 projects into clinical trials most are a long way from becoming standard therapies. This is not unexpected, as the interval between discovery and FDA approved therapeutic via clinical trials is in excess of 10 years minimum.”

 

And here is where Monty Python enters the picture. The authors quote one of the most famous lines from the series: “Nobody expects the Spanish Inquisition – because our chief weapon is surprise.”

They use that to highlight the surprises and uncertainty that stem cell research has gone through in the more than ten years since CIRM was created. They point out that a whole category of cells, induced pluripotent stem (iPS) cells, didn’t exist until 2006; and that few would have predicted the use of gene/stem cell therapy combinations. The recent development of the CRISPR/Cas9 gene-editing technology shows the field is progressing at a rate and in directions that are hard to predict; a reminder that that researchers and funding agencies should continue to expect the unexpected.

With two such different agencies the authors wisely resist the temptation to make any direct comparisons as to their success but instead conclude:

“…both CIRM and UKRMP have similar goals but different routes (and funding) to achieving them. Connecting people to work together to move regenerative medicine into the clinic is an over-arching objective and one that, we hope, will benefit patients regardless of where they live.”

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.

T cell fate and future immunotherapies rely on a tag team of genetic switches

Imagine if scientists could build microscopic smart missiles that specifically seek out and destroy deadly, hard-to-treat cancer cells in a patient’s body? Well, you don’t have to imagine it actually. With techniques such as chimeric antigen receptor (CAR) T therapy, a patient’s own T cells – immune system cells that fight off viruses and cancer cells – can be genetically modified to produce customized cell surface proteins to recognize and kill the specific cancer cells eluding the patient’s natural defenses. It is one of the most exciting and promising techniques currently in development for the treatment of cancer.

Human T Cell (Wikipedia)

Human T Cell (Wikipedia)

Although there have been several clinical trial success stories, it’s still early days for engineered T cell immunotherapies and much more work is needed to fine tune the approach as well as overcome potential dangerous side effects. Taking a step back and gaining a deeper understanding of how stem cells specialize into T cells in the first place could go a long way into increasing the efficiency and precision of this therapeutic strategy.

Enter the CIRM-funded work of Hao Yuan Kueh and others in Ellen Rothenberg’s lab at CalTech. Reporting yesterday in Nature Immunology, the Rothenberg team uncovered a time dependent array of genetic switches – some with an ON/OFF function, others with “volume” control – that together control the commitment of stem cells to become T cells.

Previous studies have shown that the protein encoded by the Bcl11b gene is the key master switch that when activated sets a “no going back” path toward a T cell fate. A group of other genes, including Runx1, TCF-1 and GATA-3 are known to play a role in activating Bcl11b. The dominant school of thought is that these proteins gradually accumulate at the Bcl11b gene and once a threshold level is achieved, the proteins combine to enable the Bcl11b activation switch to flip on. However, other studies suggest that some of these proteins may act as “pioneer” factors that loosen up the DNA structure and allow the other proteins to readily access and turn on the Bcl11b gene. Figuring out which mechanism is at play is critical to precisely manipulating T cell development through genetic engineering.

To tease out the answer, the CalTech team engineered mice such that cells with activated Bcl11b would glow which allows visualizing the fate of single cells. We reached out to Dr. Kueh on the rationale for this experimental approach:

Hao Yuan Kueh, CalTech

Hao Yuan Kueh, CalTech

“To fully understand how genes are controlled, we need to watch them turn on and off in single, living cells over time.  As cells in our body are unique and different from one another, standard measurement methods, which average over millions of cells, often do not tell us the entire picture.”

The team examined the impact of inhibiting the T cell specific proteins GATA-3 and TCF-1 at different stages in T cell development in single cells. When the production of these two proteins were blocked in very early T cell progenitor (ETPs) cells, activation of Bcl11b was dramatically reduced. But that’s not what they observed when the experiment was repeated in a later stage of T cell development. In this case, blocking GATA-3 and TCF-1 had a much weaker impact on Bcl11b. So GATA-3 and TCF-1 are important for turning on Bcl11b early in T cell development but are not necessary for maintaining Bcl11b activation at later stages.

Inhibition of Runx1, on the other hand, did lead to a reduction in Bcl11b in these later T cell development stages. Making Runx1 levels artificially high conversely led to elevated Bcl11b in these cells.

Together, these results point to GATA-3 and TCF-1 as the key factors for turning on Bcl11b to commit cells to a T cell fate and then they hand off their duties to Runx1 to keep Bcl11b on and maintaining the T cell identity. Dr. Kuhn sums up the results and their implications this way:

“Our work shows that control of gene expression is very much a team effort, where some proteins flip the gene’s master ON-OFF switch, and others set its expression levels after it turns on…These results will help us generate customized T-cells to fight cancer and other diseases.  As T-cells are specialized to recognize and fight foreign agents in our body, this therapy strategy holds much promise for diseases that are difficult to treat with standard drug-based methods.  Also, these intricate gene regulation mechanisms are likely to be in play in other cell types in our body, not just T-cells, and so we believe our results will be widely relevant.”

Stem cell stories that caught our eye: growing muscle, new blood vessels and pacemakers and Tommy John surgery

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Better way to grow muscle.  The specialized stem cells responsible for repairing muscle, the satellite cells, have always been difficult to grow in large quantities in the lab. They have a strong natural hankering to mature into muscle. Researchers have not been able to keep them in their stem cell state in the lab and that prevents creating enough of them for effective therapies for diseases like muscular dystrophy.

new muscle Kodaira

New muscle fibers in green grown in mice from satellite stem cells

A team at the National Institute of Neuroscience in Kodaira, Japan, published what seems to be a simple solution to the problem. In a press release from the publisher of the Journal of Neuromuscular Diseases posted by Science Daily they reported that adding just one protein to satellite cells allowed them to grow indefinitely in the lab and expand to the point they could provide a meaningful transplant that resulted in muscle repair in mice.

 “This research enables us to get one step closer to the optimal culture conditions for muscle stem cells,” said Shin’ichi Takeda from the institute.

The protein they used, leukemia inhibitory factor, and its downstream impacts on other genes is now the subject of their ongoing research.

 

Regenerating heart vessels. A CIRM funded team at Sanford Burnham Prebys Medical Discovery Institute (SBP) in San Diego and at Stanford University have shown that repressing a single gene can encourage the formation of new blood vessels in the heart. Creating those new conduits for oxygen after a heart attack could reduce damage to the heart muscle and prevent development of heart failure.

Building new blood vessels requires coordination of several growth factors and clinical trials evaluating individual factors have resulted in failure. The SBP team found that a single gene repressed all those needed factors and blocking it could let them do their job and create new blood vessels.

Mark Mercola

Mark Mercola

“We found that a protein called RBPJ serves as the master controller of genes that regulate blood vessel growth in the adult heart,” said senior author Mark Mercola, a professor at SBP and at Stanford, in an institute press release. “RBPJ acts as a brake on the formation of new blood vessels. Our findings suggest that drugs designed to block RBPJ may promote new blood supplies and improve heart attack outcomes.”

 The authors also suggested that RBPJ itself might be beneficial in cancer if it can inhibit the new blood vessels tumors need to thrive.

 

Bionic patch as pacemaker.  Chemists at Harvard have designed nanoscale electronic scaffolds that can be seeded with heart cells and are able to conduct current to detect irregular heart rhythms and potentially send out electrical signals to correct them.

 “Rather than simply implanting an engineered patch built on a passive scaffold, our works suggests it will be possible to surgically implant an innervated patch that would now be able to monitor and subtly adjust its performance,” said Charles Lieber the senior author in a university press release posted by Phys.Org. The research was published in Nature Nanotechnology

 With its electronics built into the patch that is integrated into the heart, Lieber suggested the bionic patch could detect heart rhythm problems sooner than traditional pace makers. Another use for the patch he suggested could be to screen potential drugs.

 

Alternate to Tommy John in pictures. Sports fans generally have a vague idea of what Tommy John surgery is. First performed on baseball pitcher Tommy John of the LA Dodgers in 1974, the surgery replaces a torn elbow tendon with one from another part of the body.  A number of baseball players in the past couple years have made headlines because they sought out an alternative to this invasive procedure using stem cells.

The players sometimes improve, but with their high-priced team doctors also demanding extensive physical therapy and other interventions, we don’t really know how much of the improvement is due to the stem cells.  I am not aware of controlled clinical trials looking at the alternative therapy.

LA Angels Andrew HeaneyBut given how much it is in the news, I thought it would be good to share this excellent info-graphic from the LA Times explaining exactly what happens with the stem cell version of the Tommy John procedure. The Times posted the graphic yesterday, and then today, papers around the country ran stories that the most recent famous recipient of the cells, Los Angeles Angels lefthander Andrew Heaney, was going to have the old-fashioned surgery today because the stem cell treatment did not work in this case.

There may be some individuals, likely those with only partial tears who might benefit from this stem cell procedure that uses a type of stem cell that is not likely to replace tendons, but can release factors that summons the body’s natural healing apparatus to do a better job.  But until more formal clinical trials are conducted, it will be hard for     doctors to know who would and would not benefit.

From flies to mice: Improving stem cell therapy for degenerative eye diseases

Stem cell therapies for degenerative eye diseases sound promising – inject retinal progenitor cells derived from human pluripotent stem cells into the eye where they will integrate and replace damaged retinal tissue to hopefully restore sight. However, a significant road block is preventing these stem cell transplants from doing their job: the transplanted cells are unable to survive and generate healthy retinal tissue due to the unhealthy, degenerative environment they find themselves in.

A retina of a patient with macular degeneration. (Photo credit: Paul Parker/SPL)

A retina of a patient with macular degeneration. (Photo credit: Paul Parker/SPL)

In patients with age-related macular degeneration or retinitis pigmentosa, retinal tissue in the eye is in a state of inflammation initiated by innate immune cells such as macrophage-derived microglia. When activated, microglia can either promote an inflammatory response or resolve inflammation and promote tissue repair and regeneration.

This balance between a pro-inflammation and tissue regeneration is something that scientists are looking to manipulate in order to develop new potential therapeutic strategies for degenerative eye diseases.

Chapter 1: Identifying MANF in flies

In a paper published today in the journal Science, Buck researchers report that they have identified a natural immune system modulator called MANF that improved the success of retinal repair in both fly and mouse models of eye diseases, and enhanced retinal cell transplantation in mouse models of photoreceptor degeneration.

The story of MANF starts with Drosophila fruit flies grown in the lab of Buck Professor Dr. Heinrich Jasper. His lab studies hemocytes, the fly equivalent of blood cells, and the repair factors that they secrete in response to injury. To model retinal damage, Jasper and his lab exposed photoreceptors in the retina of flies to UV light and then screened for secreted proteins that were released by hemocytes in response to UV damage.

They identified a protein called a secreted protein called MANF and hypothesized that this factor could promote tissue regeneration and act as a neuroprotective, “retinal repair factor”.

In a Buck Institute news release, Jasper explained how further experiments showed that MANF was secreted by hemocytes in response to UV induced damage in the retina, and that it shifted these immune cells from promoting inflammation to reducing inflammation and promoting retinal regeneration.

Chapter 2: MANF is neuroprotective in mice

Deepak Lamba and his lab

Deepak Lamba and his lab

Part two of the story involved determining whether MANF had similar neuroprotective and anti-inflammatory properties in mammalian models. Dr. Deepak Lamba, Buck Professor and co-senior author on the study, took the lead and first tested whether MANF could reduce light-induced damage of photoreceptors in mouse models of retinal degeneration.

Injecting MANF protein into the eyes of these mice significantly reduced cell death caused by light exposure. Similarly, injection of fibroblast cells that secreted MANF also had a neuroprotective effect in the damaged retina by recruiting innate immune cells to promote the body’s natural repair mechanisms.

Chapter 3: MANF improves cell transplantation in mice

The final chapter involved testing whether MANF could improve the outcome of transplanted photoreceptor cells in blind mice genetically engineered to have retinal damage. The addition of MANF improved the survival and integration of the transplanted cells in the retinas of the mice and also improved the animals’ visual function.

Lamba concluded in a Buck news release that, “MANF promotes healing and helps create a microenvironment conducive to successful transplantation.”

These preliminary results in flies and mice are encouraging and Jasper believes that the neuroprotective effects of MANF could potentially be applied to other diseases of aging at an early stage that could prevent disease progression.

Heinrich Jasper

Heinrich Jasper

“Our hope is that MANF will be useful for treatment of inflammatory conditions in many disease contexts,” Jasper explained. “Focusing on immune modulation to promote a healthy repair response to tissue damage rather than a deleterious inflammatory response is a new frontier in aging research.”

Finally a possible use for your excess fat; using it to fix your arthritic knee

shutterstock_425039020

One of the most common questions we get asked at CIRM, almost every other day to be honest, is “are there any stem cell treatments for people with arthritis in their knees?” It’s not surprising. This is a problem that plagues millions of Americans and is one of the leading causes of disability in the US.

Sadly, we have to tell people that there are no stem cell treatments for osteoarthritis (OA) in the knee that have been approved by the Food and Drug Administration (FDA). There’s also a lack of solid evidence from clinical trials that the various approaches are effective.

But that could be changing. There’s a growing number of clinical trials underway looking at different approaches to treating OA in the knee using various forms of stem cells. Sixteen of those are listed at clinicaltrials.gov. And one new study suggests that just one injection of stem cells may be able to help reduce pain and inflammation in arthritic knees, at least for six months. The operative word here being may.

The study, published in the journal Stem Cells Translational Medicine,  used adipose-derived stromal cells, a kind of stem cell taken from the patient’s own fat. Previous studies have shown that these cells can have immune boosting and anti-scarring properties.

The cells were removed by liposuction, so not only did the patient’s get a boost for their knees they also got a little fat reduction. A nice bonus if desired.

The study was quite small. It involved 18 patients, between the ages of 50 and 75, all of whom had suffered from osteoarthritis (OA) in the knee for at least a year before the treatment. This condition is caused by the cartilage in the knee breaking down, allowing bones to rub against each other, leading to pain, stiffness and swelling.

One group of patients were given a low dose of the cells (23,000) injected directly into the knee, one a medium dose (103,000) and one a high dose (503,000).

Over the next six months, the patients were closely followed to see if there were any side effects and, of course, any improvement in their condition. In a news release, Christian Jorgensen, of University Hospital of Montpellier, the director of the study, said the results were encouraging:

“Although this phase I study included a limited number of patients without a placebo arm we were able to show that this innovative treatment was well tolerated in patients with knee OA and it provided encouraging preliminary evidence of efficacy. Interestingly, patients treated with low-dose ASCs significantly improved in pain and function compared with the baseline.”

The researchers caution that the treatment doesn’t halt the progression of OA and does not restore the damaged cartilage, instead it seems to help patients by reducing inflammation.

In a news article about the study Tony Atala, director of the Wake Forest Institute for Regenerative Medicine, in Winston-Salem, N.C. and the editor of Stem Cells Translational Medicine said the study offered the patients involved another benefit:

“In fact, most of the patients (in the study group) who had previously scheduled total knee replacement surgery decided to cancel the surgery. It will be interesting to see if these improvements are seen in larger groups of study participants.”

Interesting is an understatement.

But while this is encouraging it’s important to remember it was done in a small group of patients and needs to be replicated in a much larger group before we can draw any solid conclusions. It will also be important to see if the benefits last longer than six months.

We might not have to wait too long for some answers. The researchers are already running a 2-year trial involving 150 people in Europe.

We’ll let you know what they find.

 

Another way to dial back stem cell hype (but not hope): Put a dollar figure on it

In an effort to reign in the hype surrounding stem cell research that has led to a proliferation of unapproved and potentially dangerous stem cell therapies, the International Society for Stem Cell Research (ISSCR) recently released updated guidelines outlining conduct for stem cell researchers that,  for the first time, included communications activities.  At only 1.5 pages in the 37-page document, the statements around communications asked researchers, communications professionals, institutions and the media to be more proactive in combatting stem cell hype by ensuring accuracy and balance in communications activities.

Stock Image

Stock Image

It’s too early to know what the full impact of the guidelines will be, however, the communications recommendations did generate a good deal of interest and some media, at least, have taken steps to address the issue.

Whether directly influenced by the guidelines or not, in the final plenary session of the ISSCR annual meeting last week, Professor Roger Barker, a research-clinician at the University of Cambridge, provided a candid portrayal of some of the challenges of preclinical and early clinical research.

Though he may have poked a small hole in some of the optimism that characterized the four-day conference, in providing a rare glimpse of the real costs of research, Dr. Barker might also have given us a new way to frame research to downplay hype.

Dr. Roger Barker

Dr. Roger Barker

Dr. Barker is one of many researchers across the globe working on a potential cell-based treatment for Parkinson’s Disease. Parkinson’s is a rather straightforward disease to tackle in this way, because its cause is known: the death of cells that produce the chemical dopamine. Even so, the challenges in developing a treatment are many. Apart from the design of a clinical study (which includes, for example, careful selection of the Parkinson’s patients to include; as Barker pointed out, there are two main types of Parkinson progression and one type may respond to a treatment while the other may not. This is a real concern for Barker, who commented that “a lack of rigour in selecting patients has dogged the field for the past 25 years.”), there are several other factors that need to be addressed in the pre-clinical work, such as identifying the best type of cells to use, how to scale them up and make them both GMP-compliant and standardized for reproducibility.

Such work, Barker estimated, costs between £2 and £3 million (or roughly $3-5 million, valued at pre-Brexit currency rates, one would assume). And, having invested so much to this point, you don’t even have something that can be published yet.

Running the actual clinical phase 1 study, with roughly 20 patients, will cost millions more. If it doesn’t work, you’re back to lab and in search of more pre-clinical funding.

But, assuming the study nets the desired results, it’s still only looking at safety, not efficacy. Getting it to phases 2 and 3 costs several orders of magnitude more. Put in this light, the $3 billion USD given to the California Institute for Regenerative Medicine seems like not nearly enough. The Ontario Institute for Regenerative Medicine’s $25 million CAD is nothing at all. Not that we aren’t grateful — we do what we can to maximize impact and make even a small investment worthwhile. Every step counts.

Another point to consider is whether the final therapy will be more cost-effective than existing, approved medical interventions. If it’s not, there is little incentive in pursuing it. This is the notion of headroom that I’ve heard discussed more directly at commercialization-based conferences (and is very well explained here) but is one that will become increasingly relevant to research as more basic and translational work finds its way into the clinic.

Talking about money with regard to health can be seen as tedious and even crass. The three short talks given by patient advocates at the ISSCR meeting served to emphasize this – each outlined personal tragedy connected to illness or disease: congestive heart failure at 11 years of age, four generations of a family with sickle cell disease, retinitis pigmentosa that derailed a young woman’s budding career. You simply can’t put a price on a person’s life, happiness and well-being. Each of these patients, and millions more, have hope that research will find an answer. It’s a lofty goal, one that is sometimes hard to remember in the lab trenches when a grant doesn’t materialize or a negative result sends the work back to ground zero.

And therein lies some of the tension that can easily lead to hype. We do want to fly high. We do want to deliver cures and therapies. We need to be reminded, by interactions with the patient community, of what’s at stake and what we can gain for humanity. The field should and will continue to strive to achieve these goals.

But not without responsibility. And a dose of realism.


This post appears simultaneously on OIRM Expression and appears here with permission by the author Lisa Willemse.

Spotlight on CIRM Grantee Joe Wu: Clinical Trials for Heart Disease in a Dish?

It’s always exciting to read a science article featuring a talented scientist who is breaking boundaries in the field of regenerative medicine. It’s especially exciting to us at CIRM when the scientist is a CIRM grantee.

Last week, OZY published a fun and inspiring piece on Stanford scientist Joe Wu. Dr. Wu is the Director of the Stanford Cardiovascular Institute and his lab studies how stem cells (both adult and pluripotent) function and how they can be used to model heart diseases and screen for new drug therapies. He also is a CIRM grantee and has a Disease Team Therapy Development grant that aims to clinically test human embryonic stem cell-derived cardiomyocytes (heart cells) in end stage heart failure patients.

Dr. Joe Wu. (Image Source: Sean Culligan/OZY)

Dr. Joe Wu. (Image Source: Sean Culligan/OZY)

The OZY piece does a great job of highlighting Dr. Wu’s recent efforts to use human induced pluripotent stem cells (iPS cells) to make heart tissue in a dish and model cardiovascular disease. And without getting too technical, the article explains Dr. Wu’s larger mission to combine precision medicine and stem cell research to identify drugs that would be best suited for specific patient populations.

The article commented,

“He envisions treatments based on an individual’s own iPS cells. For example, a popular breast cancer drug has an 8 percent chance of giving patients heart failure. In Wu’s world, we’d test the drug on stem cells first, and if a patient lands in that 8 percent, begin treatment for the side effects preemptively or avoiding the drug totally and avoiding heart failure, too.”

Basically, Dr. Wu sees the future of clinical trials in a dish using human stem cells. “His goal is to take these stem cells from thousands of patients to create a genetically diverse enough bank that will allow for “clinical trials in a dish” — Wu’s go-to phrase.”

Instead of following the traditional drug development paradigm that takes more than 10 years, billions of dollars, and unfortunately usually ends in failure, Dr. Wu wants to follow an accelerated path where stem cells are used for drug toxicity and efficacy testing.

This alternative path could improve overall drug development and approval by the FDA. The article explained,

“Testing drugs on stem cells will give big pharma and the FDA vastly improved heads up for toxic complications. Stem cells are “absolutely” the best avenue going forward, says Norman Stockbridge, director of the division of cardiovascular and renal products at the FDA’s Center for Drug Evaluation and Research.”

Not everyone is on the same page with Dr. Wu’s bold vision of the future of precision medicine, stem cells, and treatments for heart disease. Some believe he is overly ambitious, however top scientists in the stem cell field have praised Dr. Wu’s “systematic approach” to research and how he doesn’t stop at data discovery, he focuses on the big picture and how his work can ultimately help patients.

You can read more about Dr. Wu’s research on his lab website and I highly encourage you to check out the OZY article which is a great example of science communication for the general public.


Related Links:

Presentations at ISSCR that caught our eye: Stem cell clinical trials expand as work to improve our understanding of just how they work goes on in parallel

In a special edition of our weekly roundup, here are some highlights from just the first two days of the four-day annual meeting of the International Society for Stem Cell Research

 Seeing stem cells from both sides now. As the biggest gathering of stem cell researchers each year, the annual meeting of the International Society for Stem Cell Research offers a chance to catch up on progress across the complete spectrum of research, from fundamental exploration in the lab to clinical trials. This year’s meeting in San Francisco offers more advances toward the clinic than ever before, but it also shows a cadre of basic researchers struggling to understand what is really going on at the genetic and molecular level with some of the biggest breakthroughs of the past few years. It is a bit like the opening verse of Joni Mitchell’s song “Both Sides Now” in which she laments that even after seeing clouds as beautiful patterns and as blocks to the sun she does not really know clouds at all.

Yamanaka at ISSCR 2016

Nobelist Shinya Yamanaka at the annual ISSCR meeting

Nothing captured that spirit better than the opening talk on the second day by Nobel Prize winner Shinya Yamanaka who maintains labs at Kyoto University in Japan and at the Gladstone institutes here in San Francisco, about a mile from the site of the meeting. This year marks the 10th anniversary of his Nobel-winning discovery that you can use genetic factors to reprogram adult cells into embryonic-like stem cells called iPS cells. Even as his institute is supplying the cells for the first ever clinical trial using iPS, in this case in the blinding disease called macular degeneration, he spent much of his talk discussing his ongoing basic research trying to understand what really goes on in that reprogramming process, and why so many cells are refractory to reprogramming with only a few percent in most experiments becoming stem cells.

Before launching into his ongoing basic research—some of it from a research thread he began to unravel as a postdoc at the Gladstone—he told an enlightening tale of how he had been reprogrammed as a scientist.  He said that he went from a a basic researcher just working in his lab to someone who spent much of their time talking to government officials, bankers and donors. But he noted that like our cells, part of him was refractory to reprogramming and he still liked getting into the lab to do the basic research needed to understand the creation of iPS cells and make it it faster and more efficient, which is critical to any future role for the cells at the other end of the research pipeline—treating patients in need.

 

It takes a neighborhood. As usual much of the basic science revolved around the lab recipes needed to keep stem cells in the stem cell state in the lab, or how to efficiently direct them to become a specific type of adult tissue. On the latter there was also considerable work presented on how to get around the fact that too often the adult cells created from stem cells are not fully mature and function more like those tissues would in the fetus than they should in an adult patient.

Fiona Watt of Kings College London presented her work on studying the one “organ” that is easier to study in humans than mice: the skin hair follicle. In the furry critters the hair follicles are too close together to easily isolate individual ones. With our sparser covering it is easy to study single hair follicles, which serve as the niche that houses skin stem cells until they are needed to replenish or repair our outer barrier. In recent years, when trying to understand how stem cells stay stem cells or decide to mature into specific tissue, researchers have increasingly turned their attention to the niches all over the body that stem cells call home. They are finding that there are many facets to these homes—physical, chemical and genetic—that like any neighborhood, impact how a stem cell grows up.

Watt opened by paying tribute to a pioneer in the field who died this past year, Harvard Med School’s Howard Green, who was always a treat to interview when I was there, and who pioneered single cell analysis in skin four decades ago. Watt’s work tries to break down the various components of the skin stem cell niche in the lab to see how each contributes to cell fate. She looked at the extracellular matrix, the scaffold that holds cells in place, and found a link between the size of the hole in the scaffold and cells remaining stem cells. She also found difference between soft and hard scaffolds. She noted other factors such as the type of cell that lives next door and the oxygen level all impact the cell decisions.

She suggested that these determinants of cell fate are likely consistent across stem cell niches throughout the body and will be critical to more efficiently producing replacement tissues to help patients.

 

Jumping from A to C, skipping B.  Two researchers followed Watt who are trying to develop ways to skip the step of turning adult cells in to iPS-type stem cells and instead convert them directly into the desired tissue needed for repair. Stanford’s Marius Wernig, who cited funding from CIRM and the New York Stem Cell Foundation, reported on his work trying to improve his breakthrough from a few years ago in which he converted skin into nerve with just one genetic factor. He is investigating the underlying structures of our DNA to try to understand why only 20 percent of cells make the desired conversion. He is finding some answers but has more to ferret out.

 

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Malin Parmar

Then Malin Parmar of Sweden’s Lund University went into more detail on the fetal cell and stem cell transplant trials she is working with in Parkinson’s disease that she described at our public symposium earlier in the week. But she closed with work that she thinks could be the ultimate best solution to the disease.  Finding genetic factors that can convert other nerve cells directly into the dopamine-producing nerve cells lost in patients with the disease. She started with Wernig’s recipe and added a genetic factor known to drive cells to become dopamine nerves. She succeeded in turning brain cells called glial cells into dopamine nerves inside the brains of mice and showed they made the needed connections to other brain cells. But the work is still some years from getting to patients.

 

The complexities of the heart.  Yesterday afternoon five researchers presented different ways to figure out how to use stem cells to repair or replace a very complex organ, the heart. Shen Ding from Gladstone, who has pioneered the concept of using chemical instead of genetic factors to reprogram cells, presented his latest work in which he used that technique to grow partially mature heart cells in the lab, transplanted them into mice and saw them mature into tissue that improved heart function in a model of heart attack. He said his next experiments will involve finding a way to deliver the chemicals directly into the damaged heart to try to get the reprogramming done in the living animal.

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Stephanie Protze, of the McEwen Centre for Regenerative Medicine in Toronto, presented work on another component of the heart, the pace maker cells that ensure any new muscle cell beats at the right speed.  She described a recipe to drive stem cells to become pace maker cells, but there was a glitch. They beat at 150 beats per minute, which is the fetal rate not the adult rate. So, once again the field ran into the block of creating only partially mature tissue.

Tamer Mohamed, also of the Gladstone, presented work using chemicals to convert heart scar tissue to functional heart muscle. His work tweaked an earlier recipe that resulted in fewer than one percent of cells converting to a procedure that resulted in 30 percent. In the mouse model he saw improved heart function and reduced scarring.

University of Pittsburgh’s Lei Yang presented work on a very big, long-term goal for the field: producing a complete replacement heart. Like several other teams, his group started with a mouse donor heart and used detergents to wash away the cells so that all that was left was the scaffold of that extracellular matrix mentioned above.  He then seeded the scaffold with heart cells derived from iPS cells and let them mature.  The work resulted in what he called “beating heart constructs.”  Some of the cells beat with needed synchronicity and some did not.

All in all, the meeting exudes measured confidence. The field is clearly making rapid strides toward understanding stem cells well enough to create meaningful therapies.  However, it is ripe for what is called “reverse translation,” which is taking the findings of early clinical trials  that don’t perform quite as well as desired, and going back to  the lab to figure out how to make them better.

Circular RNAs: the Mind-Boggling Dark Matter of the Human Genome

We were just a few hours into the 2016 annual meeting of the International Society for Stem Cell Research (ISSCR) yesterday afternoon and my mind was already blown away. Pier Paolo Pandolfi of the Beth Israel Deaconess Medical Center at Harvard, spoke during the first plenary session about circular RNAs, which he dubbed, “the mind-boggling dark matter of the human genome” because their existence wasn’t confirmed until just four years ago.

To introduce the topic, Pandolfi compared human DNA to that of bacteria. Both species contain stretches of DNA sequence called genes that contain the instructions for making proteins which collectively form our bodies. Each gene is first transcribed into messenger RNA (mRNA) which in turn is translated into a protein.

Iceberg

Our DNA contains 20,000 genes. But that genetic material is just the tip of the iceberg.

But with the ability to sequence all the mRNA transcripts of an organism, or its transcriptome, came a startling fact about how differently our genetic structure is organized compared to bacteria. It turns out that 88% of DNA sequence in bacteria make up genes that code for proteins but only 2% of human DNA sequence directly codes for proteins. So what’s going with the other 98%? Scientist typically call this 98% chunk of the genome “regulatory DNA” because it contains sequences that act as control switches for turning genes on or off. But Pandolfi explained that more recent studies suggest that a whopping 70% of our genome (maybe even 95%) is transcribed into RNA but those RNA molecules just don’t get translated into protein.

 

One type of this “non-coding” RNA which we’ve blogged about plenty of times is called microRNA (miRNA). So far, about 5,000 human miRNAs have been identified compared to the 20,000 messenger RNAs that code for proteins. But by far the most abundant non-coding RNA in our transcriptome is the mysterious circular RNA (circRNA) with at least 100,000 different transcripts. circRNA was first observed as cellular structures in the 1980’s via electronic microscope images. Then in the 1990’s a scientist published DNA sequencing data suggesting the existence of circRNA. But the science community at that time panned the results, discrediting it as merely background noise of the experiments.

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Pier Paolo Pandolfi
Image: Beth Israel Deaconess Medical Center

But four years ago, the circRNAs were directly sequenced and their existence confirmed. The circRNAs are formed when messenger RNA goes through a well-described trimming process of its sequence. Some of the excised pieces of RNA form into the circular RNAs. It would seem that these circRNAs are just throw away debris but Pandolfi’s lab has found evidence that they directly play a role in cellular functions and even cancer.

His team studies a gene called Pokemon which, when genetically “knocked out” or removed from a mouse’s genome, leads to cancer. Now, it turns out this knockout not only removes the Pokemon protein but also a Pokemon circRNA (circPok). When the lab added back just the Pokemon gene, as you might expect, it acted to suppress cancer in the mice. But when just the circPok was added back, stunningly, it increased the formation of cancer in the mice. Given that genetic knockouts are one of the most pervasive techniques in biomedical science, a closer look at circRNAs that may have been overlooked in all of those results is clearly warranted.

Though this finding is somewhat scary in the fact that it’s a whole aspect of our genome that we’ve been unaware of, one fortunate aspect of circRNA is that they all carry a particular sequence which could be used as a target for a new class of drugs.

This data may extend to stem cells as well. We know that microRNAs have critical roles in regulating the maturation of stem cells into specialized cell types. Since circRNAs are thought to act by competing microRNA, it may not be long before we learn about circRNA’s role in stem cell function.

The other speakers at the first plenary session of the ISSCR annual meeting all gave high caliber talks. Luckily, Paul Knoepfler live blogged on two of those presentations. Here are the links: