CIRM-Funded Scientist is Developing a Stem Cell Therapy that Could Cure HIV

Photo Illustration by the Daily Beast

This week, UCLA scientist Scott Kitchen made the news for his efforts to develop a CIRM-funded stem cell gene therapy that could potentially cure patients infected with HIV. Kitchen’s work was profiled in the Daily Beast, which argued that his “research could significantly up survival rates from the virus.”

Scott Kitchen, UCLA Medicine

Kitchen and a team of scientists at the UCLA David Geffen School of Medicine are genetically modifying blood-forming, hematopoietic stem cells (HSCs) to express chimeric antigen receptors (CARs) that target HIV-infected cells. CARs are protein complexes on the surface of cells that are designed to recognize specific types of cells and are being developed as powerful immunotherapies to fight cancer and HIV infection.

These CAR-expressing HSCs can be transplanted into patients where they develop into immune cells called T cells and natural killer (NK) cells that will destroy cells harboring HIV. This strategy also aims to make patients resistant to HIV because the engineered immune cells will stick around to prevent further HIV infection.

By engineering a patient’s own blood-forming stem cells to produce an unlimited supply of HIV-resistant immune cells that can also eradicate HIV in other cells, Kitchen and his team are creating the possibility for a life-long, functional cure.

Dr. Kelly Shepard, Senior Science Officer of Discovery and Translation Research at CIRM, reflected on significance of Kitchen’s research in an interview:

Kelly Shepard

“This unique approach represents a two-pronged strategy whereby a patient’s own stem cells are engineered not only to be protected from new HIV infection, but also to produce HIV-specific CAR T cells that will seek out and destroy existing and new pools of HIV infection in that patient, ideally leading to a lifelong cure.”

Kitchen and his team are currently testing this stem cell-based CAR-T therapy against HIV in a large-animal model. Their latest findings, which were published recently in the journal PLOS Pathogens, showed that stem cell-derived human CAR T cells were effective at reducing the amount of HIV virus (called the viral load) in their animal-model. They also saw that the CAR T cells survived for more than two years without causing any toxic side effects. This work was funded by an earlier CIRM award led by another CIRM grantee, Dr. Jerome Zack, who is research collaborator of Kitchen’s.

In December 2017, Kitchen received a $1.7 million CIRM Discovery Stage Quest award so that the team can continue to optimize their stem cell CAR T therapy in animal models. Ultimately, they hope to gain insights into how this treatment could be further developed to treat patients with HIV.

Currently, there is no widely available cure for HIV and standard antiretroviral therapies are expensive, difficult for patients to manage and have serious side effects that reduce life expectancy. CIRM has awarded almost $75 million in funding to California scientists focused on developing novel stem cell-based therapies for HIV to address this unmet medical need. Three of these awards support early stage clinical trials, while the rest support earlier stage research projects like Kitchen’s.

CIRM Communications Director, Kevin McCormack, was quoted at the end Daily Beast article explaining CIRM’s strategy for tackling HIV:

“There are a lot of researchers working on developing stem cell therapies for HIV. We fund different approaches because at this stage we don’t know which approach will be most effective, and it may turn out that it’s ultimately a combination of these approaches, or others, that works.”

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Stem Cell RoundUp: CIRM Clinical Trial Updates & Mapping Human Brain

It was a very CIRMy news week on both the clinical trial and discovery research fronts. Here are some the highlights:

Stanford cancer-fighting spinout to Genentech: ‘Don’t eat me’San Francisco Business Times

Ron Leuty, of the San Francisco Business Times, reported this week on not one, but two news releases from CIRM grantee Forty Seven, Inc. The company, which originated from discoveries made in the Stanford University lab of Irv Weissman, partnered with Genentech and Merck KGaA to launch clinical trials testing their drug, Hu5F9-G4, in combination with cancer immunotherapies. The drug is a protein antibody that blocks a “don’t eat me” signal that cancer stem cells hijack into order to evade destruction by a cancer patient’s immune system.

Genentech will sponsor two clinical trials using its FDA-approved cancer drug, atezolizumab (TECENTRIQ®), in combination with Forty Seven, Inc’s product in patients with acute myeloid leukemia (AML) and bladder cancer. CIRM has invested $5 million in another Phase 1 trial testing Hu5F9-G4 in AML patients. Merck KGaA will test a combination treatment of its drug avelumab, or Bavencio, with Forty-Seven’s Hu5F9-G4 in ovarian cancer patients.

In total, CIRM has awarded Forty Seven $40.5 million in funding to support the development of their Hu5F9-G4 therapy product.


Novel regenerative drug for osteoarthritis entering clinical trialsThe Scripps Research Institute

The California Institute for Biomedical Research (Calibr), a nonprofit affiliate of The Scripps Research Institute, announced on Tuesday that its CIRM-funded trial for the treatment of osteoarthritis will start treating patients in March. The trial is testing a drug called KA34 which prompts adult stem cells in joints to specialize into cartilage-producing cells. It’s hoped that therapy will regenerate the cartilage that’s lost in OA, a degenerative joint disease that causes the cartilage that cushions joints to break down, leading to debilitating pain, stiffness and swelling. This news is particularly gratifying for CIRM because we helped fund the early, preclinical stage research that led to the US Food and Drug Administration’s go-ahead for this current trial which is supported by a $8.4 million investment from CIRM.


And finally, for our Cool Stem Cell Image of the Week….

Genetic ‘switches’ behind human brain evolutionScience Daily

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This artsy scientific imagery was produced by UCLA researcher Luis del la Torre-Ubieta, the first author of a CIRM-funded studied published this week in the journal, Cell. The image shows slices of the mouse (bottom middle), macaque monkey (center middle), and human (top middle) brain to scale.

The dramatic differences in brain size highlights what sets us humans apart from those animals: our very large cerebral cortex, a region of the brain responsible for thinking and complex communication. Torre-Ubieta and colleagues in Dr. Daniel Geschwind’s laboratory for the first time mapped out the genetic on/off switches that regulate the growth of our brains. Their results reveal, among other things, that psychiatric disorders like schizophrenia, depression and Attention-Deficit/Hyperactivity Disorder (ADHD) have their origins in gene activity occurring in the very earliest stages of brain development in the fetus. The swirling strings running diagonally across the brain slices in the image depict DNA structures, called chromatin, that play a direct role in the genetic on/off switches.

How Tom Howing turned to stem cells to battle back against a deadly cancer

As we enter the new year, CIRM’s 2017 Annual Report will be posted in less than two weeks!  Here’s one of the people we are profiling in the report, a patient who took part in a CIRM-funded clinical trial.

Tom Howing

In March of 2015, Tom Howing was diagnosed with stage 4 cancer. Over the next 18 months, he underwent two rounds of surgery and chemotherapy. Each time the treatments held the cancer at bay for a while. But each time the cancer returned. Tom was running out of options and hope when he heard about a CIRM-funded clinical trial using a new approach.

The clinical trial uses a therapy that blocks a protein called CD47 that is found on the surface of cancer cells, including cancer stem cells which can evade traditional therapies. CD47 acts as a ‘don’t eat me’ signal that tells immune cells not to kill off the cancer cells. When this ‘don’t eat me’ signal is blocked by the antibody, the patient’s immune system is able to identify, target and kill the cancer stem cells.

“When I was diagnosed with cancer I knew I had battle ahead of me. After the cancer came back again they recommended I try this CD47 clinical trial. I said absolutely, let’s give it a spin.

“I guess one is always a bit concerned whenever you put the adjective “experimental” in front of anything. But I’ve always been a very optimistic and positive person and have great trust and faith in my caregivers.

“Whenever you are dealing with a Phase 1 clinical trial (the earliest stage where the goal is first to make sure it is safe), there are lots of unknowns.  Scans and blood tests came back showing that the cancer appears to be held in check. My energy level is fantastic. The treatment that I had is so much less aggressive than chemo, my quality of life is just outstanding.”

Tom says he feels fortunate to be part of the clinical trial because it is helping advance research, and could ultimately help many others like him.

“The most important thing I would say is, I want people to know there is always hope and to stay positive.”

He says he feels grateful to the people of California who created CIRM and the funding behind this project: “I say a very heartfelt thank you, that this was a good investment and a good use of public funds.”

He also wants the researchers, who spent many years developing this approach, to know that they are making a difference.

“To all those people who are putting in all the hours at the bench and microscope, it’s important for them to know that they are making a huge impact on the lives of real people and they should celebrate it and revel in it and take great pride in it.”

CHLA study explains how stem cells slow progression of kidney disorder

Not all stem cell-based therapies act by replacing diseased or damaged cells. Many treatments in clinical development rely on the injected stem cells releasing proteins which trigger the slow down or even reversal of damage caused by disease or injury. A new CIRM-funded study that’s developing a stem cell therapy for a rare kidney disease uncovered a similar mechanism but with an intriguing twist. The research, published this week in Scientific Reports, suggests that the stem cells shed tiny vesicles that essentially act like sponges by trapping proteins thought to be responsible for damaging the kidney.

Amniotic fluid stem cells: a promising approach to treating kidney disease

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Network of blood-filtering blood vessels in the kidney. Image: Wikipedia

In previous studies the research team, from the Saban Research Institute of Children’s Hospital Los Angeles (CHLA), had shown that amniotic fluid stem cells can help slow the progress of Alport syndrome when injected into the kidneys of mice engineered to mimic symptoms of the disease. Alport syndrome is a genetic disease that damages the kidney’s capillaries – tiny blood vessels – which help filter the body’s blood supply. This progressive damage causes blood and proteins to leak into the urine, and leads to high blood pressure and swelling in the legs and around the eyes.

Cells in the kidney release a protein called VEGF, a stimulator of new blood vessel growth, which plays an important role in maintaining just the right balance of capillaries within the blood-filtering structures of the kidney. Excessive levels of VEGF have been associated with many diseases including kidney disorders like Alport syndrome. Although the protective effects of amniotic fluid stem cells in the mouse model of Alport syndrome were not understood, the CHLA team suspected that the cells could be interfering with the effects of the extra VEGF.

Extracellular vesicles: just another trick that nature has up its sleeve
Specifically, the scientists examined whether so-called extracellular vesicles released from the stem cells are responsible for reducing VEGF activity and slowing the disease. These vesicles are tiny pieces of cell membrane that bud off from the stem cell and carry along proteins and other cell components. Scientists used to think the vesicles were just cellular discards but countless studies have established that they actually play an important role in communication between cells.

The team showed that the vesicles released by amniotic fluid stem cells contained receptors for VEGF. When those vesicles were added to a petri dish containing VEGF and kidney blood vessel cells, the vesicles reduced the VEGF activity and protected the cells from damage. But when vesicles from stem cells lacking the VEGF receptors were used, that protection was lost. First author Sargis Sedrakyan, PhD summed up the results in a press release:

“We have demonstrated that these vesicles can be used to regulate VEGF activity and prevent the [kidney] capillary damage. We can efficiently use the vesicles to help restore normal kidney function by curbing the progression of endothelial damage in the filtration unit of the kidney.”

Back in 2013, first author Sargis Sedrakyan summarized his research in this 30 second video for the CIRM Grantee Elevator Pitch Challenge. 

Vesicles from aminotic fluid stem cells beat out FDA-approved VEGF blocker
Now anti-VEGF antibody proteins that can tightly bind and inhibit VEGF are readily available and have even been approved by the Food and Drug Administration for other disorders. So why even bother with these vesicles as a possible therapeutic strategy for Alport syndrome? Well, in side-by-side comparisons, it turns out the stem cell-derived vesicles, but not the anti-VEGF antibodies, could not only trap the VEGF but also put the brakes on VEGF production. So, it seems that the vesicles have additional properties that could make them more ideal than current approaches.

And as indicated in the press release, the CHLA team is eager to continue exploring this therapeutic strategy:

“The team’s next step will be to validate the stem cell-derived vesicle in different types of kidney disease with the final aim of finding a therapy that is effective for all patients who suffer from chronic kidney disease.”

 

UCLA scientists on track to develop a stem cell replacement therapy for Duchenne Muscular Dystrophy

Muscle cells generated by April Pyle’s Lab at UCLA.

Last year, we wrote about a CIRM-funded team at UCLA that’s on a mission to develop a stem cell treatment for patients with Duchenne muscular dystrophy (DMD). Today, we bring you an exciting update on this research just in time for the holidays (Merry Christmas and Happy Hanukkah and Kwanza to our readers!).

DMD is a deadly muscle wasting disease that primarily affects young boys and young men. The UCLA team is trying to generate better methods for making skeletal muscle cells from pluripotent stem cells to regenerate the muscle tissue that is lost in patients with the condition. DMD is caused by genetic mutations in the dystrophin gene, which codes for a protein that is essential for skeletal muscle function. Without dystrophin protein, skeletal muscles become weak and waste away.

In their previous study, the UCLA team used CRISPR gene editing technology to remove dystrophin mutations in induced pluripotent stem cells (iPSCs) made from the skin cells of DMD patients. These corrected iPSCs were then matured into skeletal muscle cells that were transplanted into mice. The transplanted muscle cells successfully produced dystrophin protein – proving for the first time that DMD mutations can be corrected using human iPSCs.

A Step Forward

The team has advanced their research a step forward and published a method for making skeletal muscle cells, from DMD patient iPSCs, that look and function like real skeletal muscle tissue. Their findings, which were published today in the journal Nature Cell Biology, address a longstanding problem in the field: not being able to make stem cell-derived muscle cells that are mature enough to model DMD or to be used for cell replacement therapies.

Dr. April Pyle, senior author on the study and Associate Professor at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA explained in a news release:

April Pyle, UCLA.

“We have found that just because a skeletal muscle cell produced in the lab expresses muscle markers, doesn’t mean it is fully functional. For a stem cell therapy for Duchenne to move forward, we must have a better understanding of the cells we are generating from human pluripotent stem cells compared to the muscle stem cells found naturally in the human body and during the development process.”

By comparing the proteins expressed on the cell surface of human fetal and adult muscle cells, the team identified two proteins, ERBB3 and NGFR, that represented a regenerative population of skeletal muscle cells. They used these two markers to isolate these regenerative muscle cells, but found that the muscle fibers they created in a lab dish were smaller than those found in human muscle.

First author, Michael Hicks, discovered that using a drug to block a human developmental signaling pathway called TGF Beta pushed these ERBB3/NGFR cells past this intermediate stage and allowed them to mature into functional skeletal muscle cells similar to those found in human muscle.

Putting It All Together

In their final experiments, the team combined the new stem cell techniques developed in the current study with their previous work using CRISPR gene editing technology. First, they removed the dystrophin mutations in DMD patient iPSCs using CRISPR. Then, they coaxed the iPSCs into skeletal muscle cells in a dish and isolated the regenerative cells that expressed ERBB3 and NGFR. Mice that lacked the dystrophin protein were then transplanted with these cells and were simultaneously given an injection of a TGF Beta blocking drug.

The results were exciting. The transplanted cells were able to produce human dystrophin and restore the expression of this protein in the Duchenne mice.

Skeletal muscle cells isolated using the ERBB3 and NGFR surface markers (right) restore human dystrophin (green) after transplantation significantly greater than previous methods (left). (Image courtesy of UCLA)

Dr. Pyle concluded,

“The results were exactly what we’d hoped. This is the first study to demonstrate that functional muscle cells can be created in a laboratory and restore dystrophin in animal models of Duchenne using the human development process as a guide.”

In the long term, the UCLA team hopes to translate this research into a patient-specific stem cell therapy for DMD patients. In the meantime, the team will use funding from a recent CIRM Quest award to make skeletal muscle cells that can regenerate long-term in response to chronic injury in hopes of developing a more permanent treatment for DMD.

The UCLA study discussed in this blog received funding from Discovery stage CIRM awards, which you can read more about here and here.

Stem Cell Stories that Caught Our Eye: GPS for Skin & Different Therapies for Aging vs. Injured Muscles?

Skin stem cells specialize into new skin by sensing neighborhood crowding
When embarking on a road trip, the GPS technology inside our smartphones helps us know where we are and how to get where we’re going. The stem cells buried in the deepest layers of our skin don’t have a GPS and yet, they do just fine determining their location, finding their correct destination and becoming the appropriate type of skin cell. And as a single organ, all the skin covering your body maintains the right density and just the right balance of skin stem cells versus mature skin cells as we grow from a newborn into adult.

crowdinginth

Skin cells growing in a petri dish (green: cytoskeleton, red: cell-cell junction protein).
Credit: MPI for Biology of Aging

This easily overlooked but amazing feat is accomplished as skin cells are continually born and die about every 30 days over your lifetime. How does this happen? It’s an important question to answer considering the skin is our first line of defense against germs, toxins and other harmful substances.

This week, researchers at the Max Planck Institute for Biology of Aging in Cologne, Germany reported a new insight into this poorly understood topic. The team showed that it all comes down to the skin cells sensing the level of crowding in their local environment. As skin stem cells divide, it puts the squeeze on neighboring stem cells. This physical change in tension on these cells “next door” triggers signals that cause them to move upward toward the skin surface and to begin maturing into skin cells.

Lead author Yekaterina Miroshnikova explained in a press release the beauty of this mechanism:

“The fact that cells sense what their neighbors are doing and do the exact opposite provides a very efficient and simple way to maintain tissue size, architecture and function.”

The research was picked up by Phys.Org on Tuesday and was published in Nature Cell Biology.

Stem cells respond differently to aging vs. injured muscle
From aging skin, we now move on to our aging and injured muscles, two topics I know oh too well as a late-to-the-game runner. Researchers at the Sanford Burnham Prebys Medical Discovery Institute (SBP) in La Jolla report a surprising discovery that muscle stem cells respond differently to aging versus injury. This important new insight could help guide future therapeutic strategies for repairing muscle injuries or disorders.

muscle stem cell

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

Muscle stem cells, also called satellite cells, make a small, dormant population of cells in muscle tissue that springs to life when muscle is in need of repair. It turns out that these stem cells are not identical clones of each other but instead are a diverse pool of cells.  To understand how the assortment of muscle stem cells might respond differently to the normal wear and tear of aging, versus damage due to injury or disease, the research team used a technology that tracks the fate of individual muscle stem cells within living mice.

The analysis showed a clear but unexpected result. In aging muscle, the muscle stem cells maintained their diversity but their ability to divide and grow declined. However, the opposite result was observed in injured muscle: the muscle stem cell diversity became limited but the capacity to divide was not affected. In a press release, team leader Alessandra Sacco explains the implications of these findings for therapy development:

sacco

Alessandra Sacco, PhD

“This study has shown clear-cut differences in the dynamics of muscle stem cell pools during the aging process compared to a sudden injury. This means that there probably isn’t a ‘one size fits all’ approach to prevent the decline of muscle stem cells. Therapeutic strategies to maintain muscle mass and strength in seniors will most likely need to differ from those for patients with degenerative diseases.”

This report was picked up yesterday by Eureka Alert and published in Cell Stem Cell.

A new study suggests CRISPR gene editing therapies should be customized for each patient

You know a scientific advance is a big deal when it becomes the main premise and title of a Jennifer Lopez-produced TV drama. That’s the case for CRISPR, a revolutionary gene-editing technology that promises to yield treatments for a wide range of genetic diseases.

In fact, clinical trials using the CRISPR method are already underway with more on the horizon. And at CIRM, we’re funding several CRISPR projects including a candidate gene and stem cell therapy that applies CRISPR to repair a genetic mutation found in sickle cell anemia patients.

geneeditingclip2

Animation by Todd Dubnicoff/CIRM

While these projects are moving full steam ahead, a study published this week in PNAS suggests a note of caution. They report that the natural genetic variability that is found when comparing  the DNA sequences of individuals has the potential to negatively impact the effectiveness of a CRISPR-based treatment and in some cases, could lead to dangerous side effects. As a result, the research team – a collaboration between Boston Children’s Hospital and the University of Montreal – recommends that therapy products using CRISPR should be customized to take into account the genetic variation between patients.

CRISPR 101
While other gene-editing methods pre-date CRISPR, the gene-editing technique has taken the research community by storm because of its ease of use. Pretty much any lab can incorporate it into their studies. CRISPR protein can cut specific DNA sequence within a person’s cells with the help of an attached piece of RNA. It’s pretty straight-forward to customize this “guide” RNA molecule so that it recognizes a desired DNA sequence that is in need of repair or modification.

https://player.vimeo.com/video/112757040

Because CRISPR activity heavily relies on the guide RNA molecule’s binding to a specific DNA sequence, there have been on-going concerns that a patient’s genetic variability could hamper the effectiveness of a given CRISPR therapy if it didn’t bind well. Even worse, if the genetic variability caused the CRISPR product to bind and inactivate a different region of DNA, say a gene responsible for suppressing cancer growth, it could lead to dangerous, so-called off target effects.

Although, studies have been carried out to measure the frequency of these potential CRISPR mismatches, many of the analyses depend on a reference DNA sequence from one individual. But as senior author Stuart Orkin, of Dana-Farber Boston Children’s Cancer and Blood Disorders Center, points out in a press release, this is not an ideal way to gauge CRISPR effectiveness and safety:

orkin

Stuart Orkin

“Humans vary in their DNA sequences, and what is taken as the ‘normal’ DNA sequence for reference cannot account for all these differences.”

 

 

One DNA sequence is not like the other
So, in this study, the research team analyzed previously published DNA sequence data from 7,444 people. And they focused on 30 disease genes that various researchers were targeting with CRISPR gene-editing. The team also generated 3,000 different guide RNAs with which to target those 30 disease genes.

The analysis showed that, in fact, about 50 percent of the guide RNAs could potentially have mismatches due to genetic variability found in these patients’ DNA sequences. These mismatches could lead to less effective binding of CRISPR to the disease gene target, which would reduce the effectiveness of the gene editing. And, though rare, the team also found cases in which an individual’s genetic variability could cause the CRISPR guide RNA to bind and cut in the wrong spot.

Matthew Canver, an MD-PhD student at Harvard Medical School who is also an author in the study, points out these less-than-ideal activities could also impact other gene editing techniques. Canver gives an overall recommendation how to best move forward with CRISPR-based therapy development:

canver, matthew

Matthew Canver

“The unifying theme is that all these technologies rely on identifying stretches of DNA bases very specifically. As these gene-editing therapies continue to develop and start to approach the clinic, it’s important to make sure each therapy is going to be tailored to the patient that’s going to be treated.”

 

Using the AIDS virus to help children battling a deadly immune disorder

Ronnie Kashyap, patient in SCID clinical trial: Photo Pawash Priyank

More than 35 million people around the world have been killed by HIV, the virus that causes AIDS. So, it’s hard to think that the same approach the virus uses to infect cells could also be used to help children battling a deadly immune system disorder. But that’s precisely what researchers at UC San Francisco and St. Jude Children’s Research Hospital are doing.

The disease the researchers are tackling is a form of severe combined immunodeficiency (SCID). It’s also known as ‘bubble baby’ disease because children are born without a functioning immune system and in the past were protected from germs within the sterile environment of a plastic bubble. Children with this disease often die of infections, even from a common cold, in the first two years of life.

The therapy involves taking the patient’s own blood stem cells from their bone marrow, then genetically modifying them to correct the genetic mutation that causes SCID. The patient is then given low-doses of chemotherapy to create space in their bone marrow for the news cells. The gene-corrected stem cells are then transplanted back into the infant, creating a new blood supply and a repaired immune system.

Unique delivery system

The novel part of this approach is that the researchers are using an inactivated form of HIV as a means to deliver the correct gene into the patient’s cells. It’s well known that HIV is perfectly equipped to infiltrate cells, so by taking an inactivated form – meaning it cannot infect the individual with HIV – they are able to use that infiltrating ability for good.

The results were announced at the American Society of Hematology (ASH) Annual Meeting and Exposition in Atlanta.

The researchers say seven infants treated and followed for up to 12 months, have all produced the three major immune system cell types affected by SCID. In a news release, lead author Ewelina Mamcarz, said all the babies appear to be doing very well:

“It is very exciting that we observed restoration of all three very important cell types in the immune system. This is something that’s never been done in infants and a huge advantage over prior trials. The initial results also suggest our approach is fundamentally safer than previous attempts.”

One of the infants taking part in the trial is Ronnie Kashyap. We posted a video of his story on our blog, The Stem Cellar.

If the stem cell-gene therapy combination continues to show it is both safe and effective it would be a big step forward in treating SCID. Right now, the best treatment is a bone marrow transplant, but only around 20 percent of infants with SCID have a sibling or other donor who is a good match. The other 80 percent have to rely on a less well-matched bone marrow transplant – usually from a parent – that can still leave the child prone to life-threatening infections or potentially fatal complications such as graft-versus-host disease.

CIRM is funding two other clinical trials targeting SCID. You can read about them here and here.

CIRM interviews Lorenz Studer: 2017 recipient of the Ogawa-Yamanaka Stem Cell Prize [Video]

For eight long years, researchers who were trying to develop a stem cell-based therapy for Parkinson’s disease – an incurable movement disorder marked by uncontrollable shaking, body stiffness and difficulty walking – found themselves lost in the proverbial wilderness. In initial studies, rodent stem cells were successfully coaxed to specialize into dopamine-producing nerve cells, the type that are lost in Parkinson’s disease. And further animal studies showed these cells could treat Parkinson’s like symptoms when transplanted into the brain.

Parkinsonsshutterstock_604375424

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Lorenz Studer, MD
Photo Credit: Sloan Kettering

But when identical recipes were used to make human stem cell-derived dopamine nerve cells the same animal experiments didn’t work. By examining the normal developmental biology of dopamine neurons much more closely, Lorenz Studer cracked the case in 2011. Now seven years later, Dr. Studer, director of the Center for Stem Cell Biology at the Memorial-Sloan Kettering Cancer Center, and his team are on the verge of beginning clinical trials to test their Parkinson’s cell therapy in patients

It’s for these bottleneck-busting contributions to the stem cell field that Dr. Studer was awarded the Gladstone Institutes’ 2017 Ogawa-Yamanaka Stem Cell Prize. Now in its third year, the prize was founded by philanthropists Hiro and Betty Ogawa along with  Shinya Yamanaka, Gladstone researcher and director of the Center for iPS Cell Research and Application at Kyoto University, and is meant to inspire and celebrate discoveries that build upon Yamanaka’s Nobel prize winning discovery of induced pluripotent stem cells (iPSCs).

LorenzStuder_OgawaAward2017-12

(L to R) Shinya Yamanaka, Andrew Ogawa, Deepak Srivastava present Lorenz Studer the 2017 Ogawa-Yamanaka Stem Cell Prize at Gladstone Institutes. Photo Credit: Todd Dubnicoff/CIRM

Studer was honored at the Gladstone in November and presented the Ogawa-Yamanka Stem Cell Prize Lecture. He was kind enough to sit down with me for a brief video interview (watch it below) a few minutes before he took the stage. He touched upon his Parkinson’s disease research as well as newer work related to hirschsprung disease, a dangerous intestinal disorder often diagnosed at birth that is caused by the loss of nerve cells in the gut. Using human embryonic stem cells and iPSCs derived from hirschsprung patients, Studer’s team has worked out the methods for making the gut nerve cells that are lost in the disease. This accomplishment has allowed his lab to better understand the disease and to make solid progress toward a stem cell-based therapy.

His groundbreaking work has also opened up the gates for other Parkinson’s researchers to make important insights in the field. In fact, CIRM is funding several interesting early stage projects aimed at moving therapy development forward:

We posted the 8-minute video with Dr. Studer today on our official YouTube channel, CIRM TV. You can watch the video here:

And for a more detailed description of Studer’s research, watch Gladstone’s webcast recording of his entire lecture:

Comparing two cellular reprogramming methods from one donor’s cells yields good news for iPSCs

In 2012, a mere six years after his discovery of induced pluripotent stem cells (iPSCs), Shinya Yamanaka was awarded the Nobel Prize in Medicine. Many Nobel winners aren’t recognized until decades after their initial groundbreaking studies. That goes to show you the importance of Yamanaka’s technique, which can reprogram a person’s cells, for example skin or blood, into embryonic stem cell-like iPSCs by just adding a small set of reprogramming factors.

These iPSCs are pluripotent, meaning they can be specialized, or differentiated, into virtually any cell type in the body. With these cells in hand, researchers have a powerful tool to study human disease and to develop treatments using human cells directly from patients. And at the same time, this cell source helps avoid the ethical concerns related to embryonic stem cells.

iPSC_Wu

Induced pluripotent stem cell (iPSC) colonies.
Image Credit: Joseph Wu

Still, there has been lingering uneasiness about how well iPSCs match up to embryonic stem cells (ESCs), considered the gold-standard of pluripotent stem cells. One source of those concerns is that the iPSC method doesn’t completely reprogram cells and they retain memory of their original cell source, in the form of chemical – also called epigenetic – modifications of the cells’ DNA structure. So, if a researcher were to make, say, heart muscle cells from iPSCs that have an epigenetic memory of its skin cell origins, any resulting conclusions about a given disease study or cell therapy could be less accurate than ESC-related results. But a report published yesterday in PNAS should help relieve these worries.

The CIRM-funded study – a collaboration between the labs of Joseph Wu and Michael Synder at Stanford University and Shoukhrat Mitalipov at Oregon Health & Science University – carried out an exhaustive series of experiments that carefully compared the gene activity and cell functions of iPSC-derived cells with cells derived from embryonic stem cells. The teams sought to compare cells generated from the same person to be sure any differences were not the result of genetics. To make this “apples-to-apples” comparison, they generated embryonic stem cells using another reprogramming technique called somatic cell nuclear transfer (SCNT).

With SCNT, a nucleus from an adult cell is transferred to an egg which has its own nucleus removed. The resulting cell becomes reprogrammed back into an embryo from which embryonic stem cells are generated – the researchers call them NT-ESCs for short. In this study, the skin cell sample used for making the iPSCs and the cell nucleus used for making the NT-ESCs came from the same person. In scientific lingo, the iPSCs and SCNT stem cells are considered isogenic.

Now, it turns out the NT-ESC reprogramming process is more complete and eliminates epigenetic memory of the original cell source. So why even bother with iPSCs if you have NT-ESCs? There are big disadvantages with SCNT: it’s a complex technique – only a limited number of labs pull it off – and it requires donated human eggs which carries ethical issues. So, if a direct comparison iPSCs and SNCT stem cells shows little difference then it would be fair to argue that iPSCs can replace NT-ESCs for deriving patient-specific stem cells.

And that’s exactly what the teams found, as Dr. Wu summarized it to me in an interview:

“Direct comparison between differentiated cells derived from iPSCs and SCNT had never been performed because it had been difficult to generate patient-specific ESCs by the SCNT method. Collaborating with Dr. Shoukhrat Mitalipov at Oregon Health & Science University and Dr. Michael Snyder at Stanford University, we compared patient-specific cardiomocytes (heart muscle cells) and endothelial (blood vessel) cells derived by these two reprogramming methods (SCNT and iPSCs) and found they were relatively equivalent regarding molecular and functional features.”

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Blood vessel cells derived by iPSC (left) and SCNT (right) reprogramming methods.
Image credit: Joseph Wu

Because the heart muscle and blood vessel cells were similar regardless of reprogramming method, it suggests that the epigenetic memory that remained in the iPSCs is less of a worry. Dr. Wu explained to me this way:

joewu

Joseph Wu

“If iPSCs carry substantial epigenetic memory of the cell-of-origin, it is unlikely these iPSCs can differentiate to a functional cardiac cell or blood vessel cell. Only the stem cells free of significant epigenetic memory can differentiate into functional cells.”

 

Hopefully these results hold up over time because it will bode well for the countless iPSC-related disease studies as well as the growing number of iPSC-related projects that are nearing clinical trials.