CIRM Board targets diabetes and kidney disease with big stem cell research awards

diabetes2

A recent study  estimated there may be more than 500 million people worldwide who have diabetes. That’s an astounding figure and makes diabetes one of the largest chronic disease epidemics in human history.

One of the most serious consequences of untreated or uncontrolled diabetes is kidney damage. That can lead to fatigue, weakness, confusion, kidney failure and even death. So two decisions taken by the CIRM Board today were good news for anyone already suffering from either diabetes or kidney disease. Or both.

The Board awarded almost $10 million to Humacyte to run a Phase 3 clinical trial of an artificial vein needed by people undergoing hemodialysis – that’s the most common form of dialysis for people with kidney damage. Hemodialysis helps clean out impurities and toxins from the blood. Without it waste will build up in the kidneys with devastating consequences.

The artificial vein is a kind of bioengineered blood vessel. It is implanted in the individual’s arm and, during dialysis, is connected to a machine to move the blood out of the body, through a filter, and then back into the body. The current synthetic version of the vein is effective but is prone to clotting and infections, and has to be removed regularly. All this puts the patient at risk.

Humacyte’s version – called a human acellular vessel or HAV – uses human cells from donated aortas that are then seeded onto a biodegradable scaffold and grown in the lab to form the artificial vein. When fully developed the structure is then “washed” to remove all the cellular tissue, leaving just a collagen tube. That is then implanted in the patient, and their own stem cells grow onto it, essentially turning it into their own tissue.

In earlier studies Humacyte’s HAV was shown to be safer and last longer than current versions. As our President and CEO, Randy Mills, said in a news release, that’s clearly good news for patients:

“This approach has the potential to dramatically improve our ability to care for people with kidney disease. Being able to reduce infections and clotting, and increase the quality of care the hemodialysis patients get could have a significant impact on not just the quality of their life but also the length of it.”

There are currently almost half a million Americans with kidney disease who are on dialysis. Having something that makes life easier, and hopefully safer, for them is a big plus.

The Humacyte trial is looking to enroll around 350 patients at three sites in California; Sacramento, Long Beach and Irvine.

While not all people with diabetes are on dialysis, they all need help maintaining healthy blood sugar levels, particularly people with type 1 diabetes. That’s where the $3.9 million awarded to ViaCyte comes in.

We’re already funding a clinical trial with ViaCyte  using an implantable delivery system containing stem cell-derived cells that is designed to measure blood flow, detect when blood sugar is low, then secrete insulin to restore it to a healthy level.

This new program uses a similar device, called a PEC-Direct. Unlike the current clinical trial version, the PEC-Direct allows the patient’s blood vessels to directly connect, or vasularize, with the cells inside it. ViaCyte believes this will allow for a more robust engraftment of the stem cell-derived cells inside it and that those cells will be better able to produce the insulin the body needs.

Because it allows direct vascularization it means that people who get the delivery system  will also need to get chronic immune suppression to stop their body’s immune system attacking it. For that reason it will be used to treat patients with type 1 diabetes that are at high risk for acute complications such as severe hypoglycemic (low blood sugar) events associated with hypoglycemia unawareness syndrome.

In a news release Paul Laikind, Ph.D., President and CEO of ViaCyte, said this approach could help patients most at risk.

“This high-risk patient population is the same population that would be eligible for cadaver islet transplants, a procedure that can be highly effective but suffers from a severe lack of donor material. We believe PEC-Direct could overcome the limitations of islet transplant by providing an unlimited supply of cells, manufactured under cGMP conditions, and a safer, more optimal route of administration.”

The Board also approved more than $13.6 million in awards under our Discovery program. You can see the winners here.

 

CIRM-funded stem cell clinical trial for retinitis pigmentosa focuses on next stage

rp1

How retinitis pigmentosa erodes normal vision

The failure rate for clinical trials is depressingly high. A study from Tufts University in 2010  found that for small molecules – the substances that make up more than 90 percent of the drugs on the market today – the odds of getting from a Phase 1 trial to approval by the Food and Drug Administration are just 13 percent. For stem cell therapies the odds are even lower.

That’s why, whenever a stem cell therapy shows good results it’s an encouraging sign, particularly when that therapy is one that we at CIRM are funding. So we were more than a little happy to hear that Dr. Henry Klassen and his team at jCyte and the University of California, Irvine have apparently cleared the first hurdle with their treatment for retinitis pigmentosa (RP).

jCyte has announced that the first nine patients treated for RP have shown no serious side effects, and they are now planning the next phase of their Phase 1/2a safety trial.

In a news release Klassen, the co-founder of jCyte, said:

“We are pleased with the results. Retinitis pigmentosa is an incurable retinal disease that first impacts people’s night vision and then progressively robs them of sight altogether. This is an important milestone in our effort to treat these patients.”

The therapy involves injecting human retinal progenitor cells into one eye to help save the light sensing cells that are destroyed by the disease. This enables the researchers to compare the treated eye with the untreated eye to see if there are any changes or improvements in vision.

So far, the trial has undergone four separate reviews by the Data Safety Monitoring Board (DSMB), an independent group of experts that examines data from trials to ensure they meet all safety standards and that results show patients are not in jeopardy. Results from the first nine people treated are encouraging.

The approach this RP trial is taking has a couple of advantages. Often when transplanting organs or cells from one person into another, the recipient has to undergo some kind of immunosuppression, to stop their body rejecting the transplant. But earlier studies show that transplanting these kinds of progenitor cells into the eye doesn’t appear to cause any immunological response. That means patients in the study don’t have to undergo any immunosuppression. Because of that, the procedure is relatively simple to perform and can be done in a doctor’s office rather than a hospital. For the estimated 1.5 million people worldwide who have RP that could make getting treatment relatively easy.

Of course the big question now is not only was it safe – it appears to be – but does it work? Did any of those people treated experience improvements in their vision? We will share those results with you as soon as the researchers make them available.

Next step for the clinical trial is to recruit more patients, and treat them with a higher number of cells. There’s still a long way to go before we will know if this treatment works, if it either slows down, stops, or better still helps reverse some of the effects of RP. But this is a really encouraging first step.


Related links:

California high schoolers SPARK interest in stem cell research through social media

I have a job for you today and it’s a fun one. Open your Instagram app on your phone. If you’re not an Instagrammer, don’t worry, you can access the website on your computer.

Do you have it open? OK now type in the hashtag #CIRMSparkLab and click on it.

What you’ll find is around 200 posts of the most inspiring and motivating pictures of stem cell research that I’ve seen. These pictures are from high school students currently participating in the CIRM summer SPARK program, one of our educational programs, which has the goal to train the next generation of stem cell scientists.

The SPARK program offers California high school students an invaluable opportunity to gain hands-on training in regenerative medicine at some of the finest stem cell research institutes in the state. And while they gain valuable research skills, we are challenging them to share their experiences with the general public through blogging and social media.

Communicating science to the public is an important mission of CIRM, and the SPARK students are excelling at this task by posting descriptive photos on Instagram that document their internships. Some of them are fun lab photos, while others are impressive images of data with detailed explanations about their research projects.

Below are a few of my favorite posts so far this summer. I’ve been so inspired by the creativity of these posts that we are now featuring some of them on the @CIRM_Stemcells account. (Yes this is a shameless plug for you to follow us on Instagram!).

City of Hope SPARK program.

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I encourage you all to follow our talented SPARK students this summer as they continue to document their exciting journeys on Instagram. These students are our future and supporting their training and education in stem cell research is an honor for CIRM and a vital step towards achieving our mission of accelerating stem cell treatments to patients with unmet medical needs.

Stay tuned for more blog coverage about SPARK and our other educational program, the Bridges to Stem Cell Research program for undergraduate and master-level students. The annual Bridges conference that brings all the students together to present their research will be held next week, and the SPARK conference is on August 8th both in Berkeley.

Stem cell transplant offers Jake a glimpse of hope

Jake

Jake Javier surrounded by friends; Photo courtesy Julie Haener KTVU

On Thursday, July 7th, Jake Javier became the latest member of a very select group. Jake underwent a stem cell transplant for a spinal cord injury at Santa Clara Valley Medical Center here in the San Francisco Bay Area.

The therapy is part of the CIRM-funded clinical trial run by Asterias Biotherapeutics. For Asterias it meant it had hit a significant milestone (more on that later). But for Jake, it was something far more important. It was the start of a whole new phase in his life.

Jake seriously injured his spinal cord in a freak accident after diving into a swimming pool just one day before he was due to graduate from San Ramon Valley high school. Thanks, in part, to the efforts of the tireless patient advocate and stem cell champion Roman Reed, Jake was able to enroll in the Asterias trial.

astopc1The goal of the trial is to test the safety of transplanting three escalating doses of AST-OPC1 cells. These are a form of cell called oligodendrocyte progenitors, which are capable of becoming several different kinds of brain cells, some of which play a supporting role and help protect nerve cells in the central nervous system – the area damaged in spinal cord injury.

To be eligible, individuals have to have experienced a severe neck injury in the last 30 days, one that has left them with no sensation or movement below the level of their injury, and that means they have typically lost all lower limb function and most hand and arm function.

The first group of three patients was completed in August of last year. This group was primarily to test for safety, to make sure this approach was not going to cause any harm to patients. That’s why the individuals enrolled were given the relatively small dose of 2 million cells. So far none of the patients have experienced any serious side effects, and some have even shown some small improvements.

In contrast, the group Jake is in were given 10 million cells each. Jake was the fifth person treated in this group. That means Asterias can now start assessing the safety data from this group and, if there are no problems, can plan on enrolling people for group 3 in about two months. That group of patients will get 20 million cells.

It’s these two groups, Jakes and group 3, that are getting enough cells that it’s hoped they will see some therapeutic benefits.

In a news release, Steve Cartt, President and CEO of Asterias, said they are encouraged by the progress of the trial so far:

“Successful completion of enrollment and dosing of our first efficacy cohort receiving 10 million cells in our ongoing Phase 1/2a clinical study represents a critically important milestone in our AST-OPC1 clinical program for patients with complete cervical spinal cord injuries. In addition, while it is still very early in the development process and the patient numbers are quite small, we are encouraged by the upper extremity motor function improvements we have observed so far in patients previously enrolled and dosed in the very low dose two million cell cohort that had been designed purely to evaluate safety.”

 

jake and familyJake and his family are well aware that this treatment is not going to be a cure, that he won’t suddenly get up and walk again. But it could help him in other, important ways, such as possibly getting back some ability to move his hands.

The latest news is that Jake is doing well, that he experienced some minor problems after the surgery but is bouncing back and is in good spirits.

Jake’s mother Isabelle said this has been an overwhelming experience for the family, but they are getting through it thanks to the love and support of everyone who hears Jake’s story. She told CIRM:

 “We are all beyond thrilled to have an opportunity of this magnitude. Just the thought of Jake potentially getting the use of his hands back gives him massive hope. Jake has a strong desire to recover to the highest possible level. He is focused and dedicated to this process. You have done well to choose him for your research. He will make you proud.”

He already has.

Jake and Brady gear

New England Patriots star quarterback Tom Brady signed a ball and jersey for Jake after hearing about the accident


Related Links:

Salk Scientists Unlock New Secrets of Autism Using Human Stem Cells

Autism is a complex neurodevelopmental disorder whose mental, physical, social and emotional symptoms are highly variable from person to person. Because individuals exhibit different combinations and severities of symptoms, the concept of autism spectrum disorder (ASD) is now used to define the range of conditions.

There are many hypotheses for why autism occurs in humans (which some estimates suggest now affects around 3.5 million people in the US). Some of the disorders are thought to be at the cellular level, where nerve cells do not develop normally and organize properly in the brain, and some are thought to be at the molecular level where the building blocks in cells don’t function properly. Scientists have found these clues by using tools such as studying human genetics and animal models, imaging the brains of ASD patients, and looking at the pathology of ASD brains to see what has gone wrong to cause the disease.

Unfortunately, these tools alone are not sufficient to recreate all aspects of ASD. This is where cellular models have stepped in to help. Scientists are now developing human stem cell derived models of ASD to create “autism in a dish” and are finding that the nerve cells in these models show characteristics of these disorders.

Stem cell models of autism and ASD

We’ve reported on some of these studies in previous blogs. A group from UCSD lead by CIRM grantee Alysson Muotri used induced pluripotent stem cells or iPS cells to model non-syndromic autism (where autism is the primary diagnosis). The work has been dubbed the “Tooth Fairy Project” – parents can send in their children’s recently lost baby teeth which contain cells that can be reprogrammed into iPS cells that can then be turned into brain cells that exhibit symptoms of autism. By studying iPS cells from individuals with non-syndromic autism, the team found a mutation in the TRPC6 gene that was linked to abnormal brain cell development and function and is also linked to Rett syndrome – a rare form of autism predominantly seen in females.

Another group from Yale generated “mini-brains” or organoids derived from the iPS cells of ASD patients. They specifically found that ASD mini-brains had an increased number of a type of nerve cell called inhibitory neurons and that blocking the production of a protein called FOXG1 returned these nerve cells back to their normal population count.

Last week, a group from the Salk Institute in collaboration with scientists at UC San Diego published findings about another stem cell model for ASD that offers new clues into the early neurodevelopmental defects seen in ASD patients.  This CIRM-funded study was led by senior author Rusty Gage and was published last week in the Nature journal Molecular Psychiatry.

Unlocking clues to autism using patient stem cells

Gage and his team were fascinated by the fact that as many as 30 percent of people with ASD experience excessive brain growth during early in development. The brains of these patients have more nerve cells than healthy individuals of the same age, and these extra nerve cells fail to organize properly and in some cases form too many nerve connections that impairs their overall function.

To understand what is going wrong in early stages of ASD, Gage generated iPS cells from ASD individuals who experienced abnormal brain growth at an early age (their brains had grown up to 23 percent faster when they were toddlers compared to normal toddlers). They closely studied how these ASD iPS cells developed into brain stem cells and then into nerve cells in a dish and compared their developmental progression to that of healthy iPS cells from normal individuals.

Neurons derived from people with ASD (bottom) form fewer inhibitory connections (red) compared to those derived from healthy individuals (top panel). (Salk Institute)

Neurons derived from people with ASD (bottom) form fewer inhibitory connections (red) compared to those derived from healthy individuals (top panel). (Salk Institute)

They quickly observed a problem with neurogenesis – a term used to describe how brain stem cells multiply and create new nerve cells in the brain. Brain stem cells derived from ASD iPS cells displayed more neurogenesis than normal brain stem cells, and thus were creating an excess amount of nerve cells. The scientists also found that the extra nerve cells failed to form as many synaptic connections with each other, an essential process that allows nerve cells to send signals and form a functional network of communication, and also behaved abnormally and overall had less activity compared to healthy neurons. Interestingly, they saw fewer inhibitory neuron connections in ASD neurons which is contrary to what the Yale study found.

The abnormal activity observed in ASD neurons was partially corrected when they treated the nerve cells with a drug called IGF-1, which is currently being tested in clinical trials as a possible treatment for autism. According to a Salk news release, “the group plans to use the patient cells to investigate the molecular mechanisms behind IGF-1’s effects, in particular probing for changes in gene expression with treatment.”

Will stem cells be the key to understanding autism?

It’s clear that human iPS cell models of ASD are valuable in helping tease apart some of the mechanisms behind this very complicated group of disorders. Gage’s opinion is that:

“This technology allows us to generate views of neuron development that have historically been intractable. We’re excited by the possibility of using stem cell methods to unravel the biology of autism and to possibly screen for new drug treatments for this debilitating disorder.”

However, to me it’s also clear that different autism stem cell models yield different results, but these differences are likely due to which populations the iPS cells are derived from. Creating more cell lines from different ASD subpopulations will surely answer more questions about the developmental differences and differences in brain function seen in adults.

Lastly, one of the co-authors on the study, Carolina Marchetto, made a great point in the Salk news release by acknowledging that their findings are based on studying cells in a dish, not actual patient’s brains. However, Marchetto believes that these cells are useful tools for studying autism:

“It never fails to amaze me when we can see similarities between the characteristics of the cells in the dish and the human disease.”

Rusty Gage and Carolina Marchetto. (Salk Institute)

Rusty Gage and Carolina Marchetto. (Salk Institute)


Related Links

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.”

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.”

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.


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