Heads or tails? Stem cells help guide the decision

Two cell embryo

There are many unknown elements for what triggers the cells in an embryo to start dividing and multiplying and becoming every single cell in the body. Now researchers at the Gladstone Institutes in San Francisco have uncovered one of those elements, how embryos determine which cells become the head and which the tail.

In this CIRM-funded study the Gladstone team, led by Dr. Todd McDevitt, discovered almost by chance how the cells align in a heads-to-tail arrangement.

Todd McDevitt

They had created an organoid made from brain cells when they noticed that some of the cells were beginning to gather in an elongated fashion, in the same way that spinal cords do in a developing fetus.

In a news article, Nick Elder, a graduate student at Gladstone and the co-author of the study, published in the journal Development, says this was not what they had anticipated would happen: “Organoids don’t typically have head-tail directionality, and we didn’t originally set out to create an elongating organoid, so the fact that we saw this at all was very surprising.”

Further study enabled the team to identify which molecules were involved in signaling specific genes to switch on and off. These were similar to the process previously identified in developing mouse embryos.

“This is such a critical point in the early development of any organism, so having a new model to observe it and study it in the lab is very exciting,” says McDevitt.

This is not just of academic interest either, it could have real world implications in helping understand what causes miscarriages or birth defects.

“We can use this organoid to get at unresolved human developmental questions in a way that doesn’t involve human embryos,” says Dr. Ashley Libby, another member of the team. “For instance, you could add chemicals or toxins that a pregnant woman might be exposed to, and see how they affect the development of the spinal cord.”

How stem cells play “follow the leader”

Todd McDevitt, PhD., Photo: courtesy Gladstone Institutes

It’s hard enough trying to follow the movements of individuals in a crowd of people but imagine how much harder it is to follow the movements of stem cells, crowded into a tiny petri dish. Well, researchers at the Gladstone Institutes in San Francisco have done just that.

In a CIRM-funded study ($5.85M) Dr. Todd McDevitt and his team created a super smart artificial intelligence way of tracking the movements of hundreds of stem cells growing together in a colony, and even identify “leaders” in the pack.

In our bodies groups of stem cells are able to move in specific ways to form different organs and tissues when exposed to the right environment. Unfortunately, we are still trying to learn what “the right environment” is for different organs.

In a news release, McDevitt, the senior author of the paper published in the journal Stem Cell Reports, says this method of observing cells may help us better understand that.

“If I wanted to make a new human heart right now, I know what types of cells are needed, and I know how to grow them independently in dishes. But we really don’t know how to get those cells to come together to form something as complex as a heart. To accomplish that, we need more insights into how cells work cooperatively to arrange themselves.”

Normally scientists watch cells by tagging them with a fluorescent marker so they can see them under a microscope. But this is slow, painstaking work and not particularly accurate. This new method used a series of what are called “neural networks”, which are artificial intelligence (AI) programs that can detect patterns in the movements of the cells. When combined together the networks proved to be able to track the movement of 95 percent of the cells. Humans by comparison can only manage up to 90 percent. But the nets were not only sharper, they were also faster, much faster, some 500 times faster.

This enhanced ability to watch the cells showed that instead of being static most of the time, as had previously been thought, they were actually on the move a lot of the time. They would move around for 15 minutes and then take a breather for ten minutes (time for the stem cell equivalent of a cup of tea perhaps).  

Some cells moved around a lot in one direction, while others just seemed to shuffle around in the same area. Some cells even seemed to act as “leaders” while other cells appeared to be “followers” and shuffle along behind them.

None of this would have been visible without the power of the AI networks and McDevitt says being able to tap into this could help researchers better understand how to use these complex movements.

“This technique gives us a much more comprehensive view of how cells behave, how they work cooperatively, and how they come together in physical space to form complex organs.

Follow the Leader is not just a kids’ game anymore. Now it’s a scientific undertaking.

Persistence pays off in search for clue to heart defects

A team of scientists led by Benoit Bruneau (left), including Irfan Kathiriya (center) and Kavitha Rao (right), make inroads into understanding what genes are improperly deployed in some cases of congenital heart disease.  Photo courtesy Gladstone Institute

For more than 20 years Dr. Benoit Bruneau has been trying to identify the causes of congenital heart disease, the most common form of birth defect in the U.S. It turns out that it’s not one cause, but many.

Congenital heart disease covers a broad range of defects, some relatively minor and others life-threatening and even fatal. It’s been known that a mutation in a gene called TBX5 is responsible for some of these defects, so, in a CIRM-funded study ($1.56 million), Bruneau zeroed in on this mutation to see if it could help provide some answers.

In the past Bruneau, the director of the Gladstone Institute of Cardiovascular Disease, had worked with a mouse model of TBX5, but this time he used human induced pluripotent stem cells (iPSCs). These are cells that can be manipulated in the lab to become any kind of cell in the human body. In a news release Bruneau says this was an important step forward.

“This is really the first time we’ve been able to study this genetic mutation in a human context. The mouse heart is a good proxy for the human heart, but it’s not exactly the same, so it’s important to be able to carry out these experiments in human cells.”

The team took some iPSCs, changed them into heart cells, and used a gene editing tool called CRISPR-Cas9 to create the kinds of mutations in TBX5 that are seen in people with congenital heart disease. What they found was some genes were affected a lot, some not so much. Which is what you might expect in a condition that causes so many different forms of problems.

“It makes sense that some are more affected than others, but this is the first experimental data in human cells to show that diversity,” says Bruneau.

But they didn’t stop there. Oh no. Then they did a deep dive analysis to understand how the different ways that different cells were impacted related to each other. They found some cells were directly affected by the TBX5 mutation but others were indirectly affected.

The study doesn’t point to a simple way of treating congenital heart disease but Bruneau says it does give us a much better understanding of what’s going wrong, and perhaps will give us better ideas on how to stop that.

“Our new data reveal that the genes are really all part of one network—complex but singular—which needs to stay balanced during heart development. That means if we can figure out a balancing factor that keeps this network functioning, we might be able to help prevent congenital heart defects.”

The study is published in the journal Developmental Cell.

Gladstone scientists respond to coronavirus pandemic

In these uncertain times, we often look to our top scientists for answers as well as potential solutions. But where does one begin to try and solve a problem of this magnitude? The first logical step is building on the supplies currently available, the work already accomplished, and the knowledge acquired.

This is the approach that the Gladstone Institutes in San Francisco is taking. Various scientists at this institution have shifted their current operations towards helping with the current coronavirus pandemic. These efforts have focused on helping with diagnostics, treatment, and prevention of COVID-19.

Diagnostics

Dr. Jennifer Doudna and Dr. Melanie Ott are collaborating in order to develop an effective method to rapidly diagnose those with COVID-19. Dr. Doudna’s work has focused on CRISPR technology, which we have talked about in detail in a previous blog post, while Dr. Ott has focused on studying viruses. By combining their expertises, these two scientists hope to develop a diagnostic tool capable of delivering rapid results and usable in areas such as airports, ports of entry, and remote communities.

Treatment

Dr. Nevan Krogan has discovered all of the human host cell proteins that COVID-19 interacts with to hijack the cell’s machinery. These proteins serve as new targets for potential drug therapies.

Since the high fatality rate of the virus is driven by lung and heart failure, Dr. Ott, Dr. Bruce Conklin, and Dr. Todd McDevitt will test effects of the virus and potential drug therapies in human lung organoids and human heart cells, both developed from human stem cells.

Dr. Warner Greene, who also focuses on the study of viruses, is screening a variety of FDA-approved drugs to identify those that could be rapidly repurposed as a treatment for COVID-19 patients or even as a preventive for high risk-groups.

Prevention

Dr. Leor Weinberger has developed a new approach to fight the spread of viruses. It is called therapeutic interfering particles (TIPs) and could be an alternative to a vaccine. TIPs are defective virus fragments that mimic the virus but are not able to replicate. They combat the virus by hijacking the cell machinery to transform virus-infected cells into factories that produce TIPS, amplifying the effect of TIPs in stopping the spread of virus. TIPs targeting COVID-19 would transmit along the same paths as the virus itself, and thus provide protection to even the most vulnerable populations.

You can read more about these groundbreaking projects in the news release linked here.

When Google turns on you, you know you are in trouble

For years CIRM and others in the stem cell community (hello Paul Knoepfler) have been warning people about the dangers of going to clinics offering unproven and unapproved stem cell therapies. Recently the drum beat of people and organizations coming out in support of that stand has grown louder and louder. Mainstream media – TV and print – have run articles about these predatory clinics. And now, Google has joined those ranks, announcing it will restrict ads promoting these clinics.

“We regularly review and revise our advertising policies. Today, we’re announcing a new Healthcare and medicines policy to prohibit advertising for unproven or experimental medical techniques such as most stem cell therapy, cellular (non-stem) therapy, and gene therapy.”

Deepak Srivastava: Photo courtesy Gladstone Institutes

The president of the International Society for Stem Cell Research (ISSCR) Dr. Deepak Srivastava quickly issued a statement of support, saying:

“Google’s new policy banning advertising for speculative medicines is a much-needed and welcome step to curb the marketing of unscrupulous medical products such as unproven stem cell therapies. While stem cells have great potential to help us understand and treat a wide range of diseases, most stem cell interventions remain experimental and should only be offered to patients through well-regulated clinical trials. The premature marketing and commercialization of unproven stem cell products threatens public health, their confidence in biomedical research, and undermines the development of legitimate new therapies.”

Speaking of Deepak – we can use first names here because we are not only great admirers of him as a physician but also as a researcher, which is why we have funded some of his research – he has just published a wonderfully well written article criticizing these predatory clinics.

The article – in Scientific American – is titled “Don’t Believe Everything You Hear About Stem Cells” and rather than paraphrase his prose, I think it best if you read it yourself. So, here it is.

Enjoy.

Don’t Believe Everything You Hear about Stem Cells

The science is progressing rapidly,but bad actors have co-opted stem cells’ hope and promise by preying on unsuspecting patients and their families

Stem cell science is moving forward rapidly, with potential therapies to treat intractable human diseases on the horizon.Clinical trials are now underway to test the safety and effectiveness of stem cell–based treatments for blindness,spinal cord injury,heart disease,Parkinson’s disease, and more,some with early positive results.A sense of urgency drives the scientific community, and there is tremendous hope to finally cure diseases that, to date, have had no treatment.


But don’t believe everything you hear about stem cells. Advertisements and pseudo news articles promote stem cell treatments for everything from Alzheimer’s disease,autism and ALS, to cerebral palsy and other diseases.The claims simply aren’t true–they’re propagated by people wanting to make money off of a desperate and unsuspecting or unknowing public.Patients and their families can be misled by deceptive marketing from unqualified physicians who often don’t have appropriate medical credentials and offer no scientific evidence of their claims.In many cases, the cells being utilized are not even true stem cells.

Advertisements for stem cell treatments are showing up everywhere, with too-good-to-be-true claims and often a testimonial or two meant to suggest legitimacy or efficacy.Beware of the following:

    •       Claims that stem cell treatments can treat a wide range of diseases using a singular stem cell type. This is unlikely to be true.

    •       Claims that stem cells taken from one area of the body can be used to treat another, unrelated area of the body. This is also unlikely to be true.     •       Patient testimonials used to validate a particular treatment, with no scientific evidence. This is a red flag.

    •       Claims that evidence doesn’t yet exist because the clinic is running a patient-funded trial. This is a red flag; clinical trials rarely require payment for experimental treatment.

    •       Claims that the trial is listed on ClinicalTrials.gov and is therefore NIH-approved. This may not be true. The Web site is simply a listing; not all are legitimate trials.

    •       The bottom line: Does the treatment sound too good to be true? If so, it probably is. Look for concrete evidence that the treatment works and is safe.

Hundreds of clinics offer costly, unapproved and unproven stem cell interventions, and patients may suffer physical and financial harm as a result.A Multi-Pronged Approach to Deal with Bad Actors 

The International Society for Stem Cell Research (ISSCR)has long been concerned that bad actors have co-opted the hope and promise of stem cell science to prey on unsuspecting patients and their families.

We read with sadness and disappointment the many stories of people trying unproven therapies and being harmed, including going blind from injections into the eyes or suffering from a spinal tumor after an injection of stem cells.Patients left financially strapped, with no physical improvement in their condition and no way to reclaim their losses, are an underreported and underappreciated aspect of these treatments.

Since late 2017, the Food and Drug Administration has stepped up its regulatory enforcement of stem cell therapies and provided a framework for regenerative medicine products that provides guidelines for work in this space.The agency has alerted many clinics and centers that they are not in compliance and has pledged to bring additional enforcement action if needed.

A Multi-Pronged Approach to Deal with Bad Actors  The International Society for Stem Cell Research (ISSCR) has long been concerned that bad actors have co-opted the hope and promise of stem cell science to prey on unsuspecting patients and their families.

We read with sadness and disappointment the many stories of people trying unproven therapies and being harmed, including going blind from injections into the eyesor suffering from a spinal tumor after an injection of stem cells.Patients left financially strapped, with no physical improvement in their condition and no way to reclaim their losses, are an underreported and underappreciated aspect of these treatments.

Since late 2017, the Food and Drug Administration has stepped up its regulatory enforcement of stem cell therapies and provided a framework for regenerative medicine products that provides guidelines for work in this space.The agency has alerted many clinics and centers that they are not in compliance and has pledged to bring additional enforcement action if needed.

In recent weeks, a federal judge granted the FDA a permanent injunction against U.S. Stem Cell, Inc. and U.S. Stem Cell Clinic, LLC for adulterating and misbranding its cellular products and operating outside of regulatory authority.We hope this will send a strong message to other clinics misleading patients with unapproved and potentially harmful cell-based products.

The Federal Trade Commission has also helped by identifying and curtailing unsubstantiated medical claims in advertising by several clinics. Late in 2018 the FTC won a $3.3-million judgment against two California-based clinics for deceptive health claims. The Federal Trade Commission has also helped by identifying and curtailing unsubstantiated medical claims in advertising by several clinics. Late in 2018 the FTC won a $3.3-million judgment against two California-based clinics for deceptive health claims.

These and other actions are needed to stem the tide of clinics offering unproved therapies and the people who manage and operate them.

Improving Public Awareness

We’re hopeful that the FDA will help improve public awareness of these issues and curb the abuses on ClinicalTrials.gov,a government-run Web site being misused by rogue clinics looking to legitimize their treatments. They list pay-to-participate clinical trials on the site, often without developing, registering or administering a real clinical trial.

The ISSCR Web site A Closer Look at Stem Cellsincludes patient-focused information about stem cells,with information written and vetted by stem cell scientists.The site includes how and where to report adverse events and false marketing claims by stem cell clinics.I encourage you to visit and learn about what is known and unknown about stem cells and their potential for biomedicine.The views expressed are those of the author(s) and are not necessarily those of Scientific American.

How stem cells know the right way to make a heart . And what goes wrong when they don’t

Gladstone scientists Deepak Srivastava (left), Yvanka De Soysa (center), and Casey Gifford (right) publish a complete catalog of the cells involved in heart development.

The invention of GPS navigation systems has made finding your way around so much easier, providing simple instructions on how to get from point A to point B. Now, a new study shows that our bodies have their own internal navigation system that helps stem cells know where to go, and when, in order to build a human heart. And the study also shows what can go wrong when even a few cells fail to follow directions.

In this CIRM-supported study, a team of researchers at the Gladstone Institutes in San Francisco, used a new technique called single cell RNA sequencing to study what happens in a developing heart. Single cell RNA sequencing basically takes a snapshot photo of all the gene activity in a single cell at one precise moment. Using this the researchers were able to follow the activity of tens of thousands of cells as a human heart was being formed.

In a story in Science and Research Technology News, Casey Gifford, a senior author on the study, said this approach helps pinpoint genetic variants that might be causing problems.

“This sequencing technique allowed us to see all the different types of cells present at various stages of heart development and helped us identify which genes are activated and suppressed along the way. We were not only able to uncover the existence of unknown cell types, but we also gained a better understanding of the function and behavior of individual cells—information we could never access before.”

Then they partnered with a team at Luxembourg Centre for Systems Biomedicine (LCSB) of the University of Luxembourg which ran a computational analysis to identify which genes were involved in creating different cell types. This highlighted one specific gene, called Hand2, that controls the activity of thousands of other genes. They found that a lack of Hand2 in mice led to an inability to form one of the heart’s chambers, which in turn led to impaired blood flow to the lungs. The embryo was creating the cells needed to form the chamber, but not a critical pathway that would allow those cells to get where they were needed when they were needed.

Gifford says this has given us a deeper insight into how cells are formed, knowledge we didn’t have before.

“Single-cell technologies can inform us about how organs form in ways we couldn’t understand before and can provide the underlying cause of disease associated with genetic variations. We revealed subtle differences in very, very small subsets of cells that actually have catastrophic consequences and could easily have been overlooked in the past. This is the first step toward devising new therapies.”

These therapies are needed to help treat congenital heart defects, which are the most common and deadly birth defects. There are more than 2.5 million Americans with these defects. Deepak Srivastava, President of Gladstone and the leader of the study, said the knowledge gained in this study could help developed strategies to help address that.

“We’re beginning to see the long-term consequences in adults, and right now, we don’t really have any way to treat them. My hope is that if we can understand the genetic causes and the cell types affected, we could potentially intervene soon after birth to prevent the worsening of their state over time.

The study is published in the journal Nature.

NIH-scientists are told to stop buying fetal tissue for research, highlighting importance of CIRM’s voter-created independence

NIH_Clinical_Research_Center_aerial

National Institutes of Health

The news that President Trump’s administration has told scientists employed by the National Institutes of Health (NIH) that they can’t buy any new human fetal tissue for research has left many scientists frustrated and worried.

The news has also highlighted the reason why voters created CIRM in the first place and the importance of having an independent source of funding for potentially life-saving research such as this.

The Trump administration imposed the suspension of all new acquisitions saying it wants to review all fetal tissue research funded by the federal government. The impact was felt immediately.

In an article on ScienceMag.com, Warner Greene, director of the Center for HIV Cure Research at the Gladstone Institutes in San Francisco, said the decision derailed collaboration between his lab and one at Rocky Mountain Laboratories in Hamilton, Montana. The research focused on an antibody that previous studies showed might prevent HIV from establishing reservoirs in the human body.

“We were all poised to go and then the bombshell was dropped. The decision completely knocked our collaboration off the rails. We were devastated.”

Right now, it’s not clear if the “halt” is temporary or permanent, or if it will ultimately be expanded beyond scientists employed by the NIH to all scientists funded by the NIH who use fetal tissue.

In 2001, President George W. Bush’s decision to impose restrictions on federal funding for embryonic stem cell research helped generate support for Proposition 71, the voter-approved initiation that created CIRM. People felt that stem cell research had potential to develop treatments and cures for deadly diseases and that if the federal government wasn’t going to support it then California would.

CIRM Board member, and Patient Advocate for HIV/AIDS, Jeff Sheehy says the current actions could have wide-reaching impact.

“While the initial focus of the emerging ban on the use of fetal tissue has been on projects related to HIV, this action undermines a spectrum of vital research initiatives that seek to cure multiple life-threatening diseases and conditions.  Many regenerative medicine cell-based or gene therapies require pre-clinical safety studies in humanized mice created with fetal tissue.  These mice effectively have human immune systems, which allows researchers to examine the effects of products on the immune system. Work to prevent and treat infectious diseases, including vaccine efforts, require this animal model to do initial testing. Development of vaccines to respond to actual threats requires use of this animal model.  This action could have damaging effects on the health of Americans.”

 

Research Targeting Prostate Cancer Gets Almost $4 Million Support from CIRM

Prostate cancer

A program hoping to supercharge a patient’s own immune system cells to attack and kill a treatment resistant form of prostate cancer was today awarded $3.99 million by the governing Board of the California Institute for Regenerative Medicine (CIRM)

In the U.S., prostate cancer is the second most common cause of cancer deaths in men.  An estimated 170,000 new cases are diagnosed each year and over 29,000 deaths are estimated in 2018.  Early stage prostate cancer is usually managed by surgery, radiation and/or hormone therapy. However, for men diagnosed with castrate-resistant metastatic prostate cancer (CRPC) these treatments often fail to work and the disease eventually proves fatal.

Poseida Therapeutics will be funded by CIRM to develop genetically engineered chimeric antigen receptor T cells (CAR-T) to treat metastatic CRPC. In cancer, there is a breakdown in the natural ability of immune T-cells to survey the body and recognize, bind to and kill cancerous cells. Poseida is engineering T cells and T memory stem cells to express a chimeric antigen receptor that arms these cells to more efficiently target, bind to and destroy the cancer cell. Millions of these cells are then grown in the laboratory and then re-infused into the patient. The CAR-T memory stem cells have the potential to persist long-term and kill residual cancer calls.

“This is a promising approach to an incurable disease where patients have few options,” says Maria T. Millan, M.D., President and CEO of CIRM. “The use of chimeric antigen receptor engineered T cells has led to impressive results in blood malignancies and a natural extension of this promising approach is to tackle currently untreatable solid malignancies, such as castrate resistant metastatic prostate cancer. CIRM is pleased to partner on this program and to add it to its portfolio that involves CAR T memory stem cells.”

Poseida Therapeutics plans to use the funding to complete the late-stage testing needed to apply to the Food and Drug Administration for the go-ahead to start a clinical trial in people.

Quest Awards

The CIRM Board also voted to approve investing $10 million for eight projects under its Discovery Quest Program. The Quest program promotes the discovery of promising new stem cell-based technologies that will be ready to move to the next level, the translational category, within two years, with an ultimate goal of improving patient care.

Among those approved for funding are:

  • Eric Adler at UC San Diego is using genetically modified blood stem cells to treat Danon Disease, a rare and fatal condition that affects the heart
  • Li Gan at the Gladstone Institutes will use induced pluripotent stem cells to develop a therapy for a familial form of dementia
  • Saul Priceman at City of Hope will use CAR-T therapy to develop a treatment for recurrent ovarian cancer

Because the amount of funding for the recommended applications exceeded the money set aside, the Application Subcommittee voted to approve partial funding for two projects, DISC2-11192 and DISC2-11109 and to recommend, at the next full Board meeting in October, that the projects get the remainder of the funds needed to complete their research.

The successful applications are:

 

APPLICATION

 

TITLE

 

INSTITUTION

CIRM COMMITTED FUNDING
DISC2-11131 Genetically Modified Hematopoietic Stem Cells for the

Treatment of Danon Disease

 

 

U.C San Diego

 

$1,393,200

 

DISC2-11157 Preclinical Development of An HSC-Engineered Off-

The-Shelf iNKT Cell Therapy for Cancer

 

 

U.C. Los Angeles

 

$1,404,000

DISC2-11036 Non-viral reprogramming of the endogenous TCRα

locus to direct stem memory T cells against shared

neoantigens in malignant gliomas

 

 

U.C. San Francisco

 

$900,000

DISC2-11175 Therapeutic immune tolerant human islet-like

organoids (HILOs) for Type 1 Diabetes

 

 

Salk Institute

 

$1,637,209

DISC2-11107 Chimeric Antigen Receptor-Engineered Stem/Memory

T Cells for the Treatment of Recurrent Ovarian Cancer

 

 

City of Hope

 

$1,381,104

DISC2-11165 Develop iPSC-derived microglia to treat progranulin-

deficient Frontotemporal Dementia

 

 

Gladstone Institutes

 

$1,553,923

DISC2-11192 Mesenchymal stem cell extracellular vesicles as

therapy for pulmonary fibrosis

 

 

U.C. San Diego

 

$865,282

DISC2-11109 Regenerative Thymic Tissues as Curative Cell

Therapy for Patients with 22q11 Deletion Syndrome

 

 

Stanford University

 

$865,282

 

 

Gladstone scientists tackle heart failure by repairing the heart from within

Modern medicine often involves the development of a drug or treatment outside the body, which is then given to a patient to fix, improve or even prevent their condition. But what if you could regenerate or heal the body using the cells and tissue already inside a patient?

Scientists at the Gladstone Institutes are pursuing such a strategy for heart disease. In a CIRM-funded study published today in the journal Cell, the team identified four genes that can stimulate adult heart muscle cells, called cardiomyocytes, to divide and proliferate within the hearts of living mice. This discovery could be further developed as a strategy to repair cardiac tissue damage caused by heart disease and heart attacks.

Regenerating the Heart

Heart disease is the leading cause of death in the US and affects over 24 million people around the world. When patients experience a heart attack, blood flow is restricted to the heart, and parts of the heart muscle are damaged or die due to the lack of oxygen. The heart is unable to regenerate new healthy heart muscle, and instead, cardiac fibroblasts generate fibrous scar tissue to heal the injury. This scar tissue impairs the heart’s ability to pump blood, causing it to work harder and putting patients at risk for future heart failure.

Deepak Srivastava, President of the Gladstone Institutes and a senior investigator there, has dedicated his life’s research to finding new ways to regenerate heart tissue. Previously, his team developed methods to reprogram mouse and human cardiac fibroblasts into beating cardiomyocytes in hopes of one day restoring heart function in patients. The team is advancing this research with the help of a CIRM Discovery Stage research grant, which will aid them in developing a gene therapy product that delivers reprogramming factors into scar tissue cells to regenerate new heart muscle.

In this new study, Srivastava took a slightly different approach and attempted to coax cardiomyocytes, rather than cardiac fibroblasts, to divide and regenerate the heart. During development, fetal cardiomyocytes rapidly divide to create heart tissue. This regenerative ability is lost in adult cardiomyocytes, which are unable to divide because they’ve already exited the cell cycle (a series of phases that a cell goes through that ultimately results in its division).

Deepak Srivastava (left) and first author Tamer Mohamed (right). Photo credits: Diana Rothery.

Unlocking proliferative potential

Srivastava had a hunch that genes specifically involved in the cell division could be used to jump-start an adult cardiomyocyte’s re-entry into the cell cycle. After some research, they identified four genes (referred to as 4F) involved in controlling cell division. When these genes were turned on in adult cardiomyocytes, the cells started to divide and create new heart tissue.

This 4F strategy worked in mouse and rat cardiomyocytes and also was successful in stimulating cell division in 15%-20% of human cardiomyocytes. When they injected 4F into the hearts of mice that had suffered heart attacks, they observed an improvement in their heart function after three months and a reduction in the size of the scar tissue compared to mice that did not receive the injection.

The team was able to further refine their method by replacing two of the four genes with chemical inhibitors that had similar functions. Throughout the process, the team did not observe the development of heart tumors caused by the 4F treatment. They attributed this fact to the short-term expression of 4F in the cardiomyocytes. However, Srivastava expressed caution towards using this method in a Gladstone news release:

“In human organs, the delivery of genes would have to be controlled carefully, since excessive or unwanted cell division could cause tumors.”

First stop heart, next stop …

This study suggests that it’s possible to regenerate our tissues and organs from within by triggering adult cells to re-enter the cell cycle. While more research is needed to ensure this method is safe and worthy of clinical development, it could lead to a regenerative treatment strategy for heart failure.

Srivastava will continue to unravel the secrets to the proliferative potential of cardiomyocytes but predicts that other labs will pursue similar methods to test the regenerative potential of adult cells in other tissues and organs.

“Heart cells were particularly challenging because when they exit the cell cycle after birth, their state is really locked down—which might explain why we don’t get heart tumors. Now that we know our method is successful with this difficult cell type, we think it could be used to unlock other cells’ potential to divide, including nerve cells, pancreatic cells, hair cells in the ear, and retinal cells.”


Related Links:

Stem Cell Stories that Caught Our Eye: New law to protect consumers; using skin to monitor blood sugar; and a win for the good guys

Hernendez

State Senator Ed Hernandez

New law targets stem cell clinics that offer therapies not approved by the FDA

For some time now CIRM and others around California have been warning consumers about the risks involved in going to clinics that offer stem cell therapies that have not been tested in a clinical trial or approved by the U.S. Food and Drug Administration (FDA) for use in patients.

Now a new California law, authored by State Senator Ed Hernandez (D-West Covina) attempts to address that issue. It will require medical clinics whose stem cell treatments are not FDA approved, to post notices and provide handouts to patients warning them about the potential risk.

In a news release Sen. Hernandez said he hopes the new law, SB 512, will protect consumers from early-stage, unproven experimental therapies:

“There are currently over 100 medical offices in California providing non-FDA approved stem cell treatments. Patients spend thousands of dollars on these treatments, but are totally unaware of potential risks and dangerous side effects.”

Sen. Hernandez’s staffer Bao-Ngoc Nguyen crafted the bill, with help from CIRM Board Vice Chair Sen. Art Torres, Geoff Lomax and UC Davis researcher Paul Knoepfler, to ensure it targeted only clinics offering non-FDA approved therapies and not those offering FDA-sanctioned clinical trials.

For example the bill would not affect CIRM’s Alpha Stem Cell Clinic Network because all the therapies offered there have been given the green light by the FDA to work with patients.

Blood_Glucose_Testing 

Using your own skin as a blood glucose monitor

One of the many things that people with diabetes hate is the constant need to monitor their blood sugar level. Usually that involves a finger prick to get a drop of blood. It’s simple but not much fun. Attempts to develop non-invasive monitors have been tried but with limited success.

Now researchers at the University of Chicago have come up with another alternative, using the person’s own skin to measure their blood glucose level.

Xiaoyang Wu and his team accomplished this feat in mice by first creating new skin from stem cells. Then, using the gene-editing tool CRISPR, they added in a protein that sticks to sugar molecules and another protein that acts as a fluorescent marker. The hope was that the when the protein sticks to sugar in the blood it would change shape and emit fluorescence which could indicate if blood glucose levels were too high, too low, or just right.

The team then grafted the skin cells back onto the mouse. When those mice were left hungry for a while then given a big dose of sugar, the skin “sensors” reacted within 30 seconds.

The researchers say they are now exploring ways that their findings, published on the website bioRxiv, could be duplicated in people.

While they are doing that, we are supporting ViaCytes attempt to develop a device that doesn’t just monitor blood sugar levels but also delivers insulin when needed. You can read about our recent award to ViaCyte here.

Deepak

Dr. Deepak Srivastava

Stem Cell Champion, CIRM grantee, and all-round-nice guy named President of Gladstone Institutes

I don’t think it would shock anyone to know that there are a few prima donnas in the world of stem cell research. Happily, Dr. Deepak Srivastava is not one of them, which makes it such a delight to hear that he has been appointed as the next President of the Gladstone Institutes in San Francisco.

Deepak is a gifted scientist – which is why we have funded his work – a terrific communicator and a really lovely fella; straight forward and down to earth.

In a news release announcing his appointment – his term starts January 1 next year – Deepak said he is honored to succeed the current President, Sandy Williams:

“I joined Gladstone in 2005 because of its unique ability to leverage diverse basic science approaches through teams of scientists focused on achieving scientific breakthroughs for mankind’s most devastating diseases. I look forward to continue shaping this innovative approach to overcome human disease.”

We wish him great success in his new role.