Stem cell stories that caught our eye: Salamander limb regrowth, mass producing cells for kidneys and halting cancer stem cells

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

Fun with axolotls.  Axolotls, the albino aquatic critters that look like they have feathers growing out of the backs of their heads, have long been a favorite model for studying how they and their salamander cousins regrow limbs. But only recently, with refined methods for turning specific genes on and off, have we begun to really understand this amazing feat.

b115a-axolotl

Carl Zimmer, national correspondent for the online publication STAT, interviewed Jessica Whited of Harvard-affiliated Brigham and Women’s Hospital about her work trying to understand the genetics of limb regrowth and posted both a four-minute video and a short story about the research. Part of the video series Zimmer calls “Science Happens,” the interview lets Whited explain that when a limb is cut off, the animal summons cells called blastemas to the stump. Those cells have properties like stem cells in that they can make different tissues like the bone, skin and muscle needed to grow a limb, but they seem to do this by selectively turning genes on and off.

With a mix of cartoon drawings and real lab images, the video provides an easy to follow explanation of how the researchers turn off individual genes and then look for the effect. And I have to say I agree with Zimmer when talking about the axolotls he declares “I think they’re creepy.”

 

Advance for kidney disease.  Often in stem cell research you don’t want the starting stem cell and you don’t want the end desired tissue, you want the middleman called a progenitor that has already decided it wants to become the end tissue, but can still mass produce itself. Instead of being handed a roll of 10 dollar bills, you have a printing press with Hamilton’s face already set on the printing plate.

kidney progenitors Salk

Progenitor cells (bright red) growing in a kidney

In CIRM-funded research published this week in Cell Stem Cell a team at the Salk Institute has found a way to configure that printing press for nephron progenitor cells, the cells that yield the vital nephrons that allow your kidneys to cleanse your blood. While many have tried to mass produce these vital cells to repair damaged kidneys, they have not had much luck. These cells do not like to stay in the progenitor state. Once they are on the path toward the end tissue they like to keep on moving in that direction.

The Salk team, led by Juan Carlos Izpisua Belmonte, got around this by changing the progenitor cells’ environment. Instead of a flat lab dish, they grew them in 3D cultures and gave them a new mix of signaling molecules.

“We provide a proof-of-principle for how to make and maintain unlimited numbers of precursor kidney cells,” said Izpisua Belmonte in an institute press release posted by HealthMedicineNet. “Having a supply of these cells could be a starting point to grow functional organs in the laboratory as well as a way to begin applying cell therapy to kidneys with malfunctioning genes.”

Their system worked first in mouse cells and then in human cells. They predicted that the methods could be used to grow progenitor cells for many other tissues.

 

Halting cancer stem cells. The bad guys of the stem cell world, cancer stem cells (CSCs), are turning out to have a number of vulnerabilities, and many companies around the world have staked their fortunes on attacking one of those weak spots. While we have known for some time that CSCs require proteins in the Wnt family to grow, we haven’t had a good way of blocking that path. Now researchers at the Riken Center and National Cancer Center in Japan claim they have a candidate drug, at least for colon cancer.

They screened a library of compounds likely to inhibit the Wnt pathway and tested them in mice that had received transplants of human colon cancer. They found one, NCB-0846 that can be administered orally, that was able to suppress the cancer grafts.

 “We’re very encouraged by our promising preclinical data for NCB-0846, especially considering the difficulty in targeting this pathway to date, and shortly we hope to conduct a clinical trial at the NCC hospitals” said Dr. Tesshi Yamada of the National Cancer Center in a Riken release posted by ScienceCodex.

CIRM funds several team trying to halt CSCs, each team targeting a different vulnerability on the CSCs, including teams at Stanford, and at University of California campuses in San Diego and Los Angeles.

How many stem cell trials will it take to get a cure?

When I think about how many clinical trials it will take before a stem cell therapy is available to patients, I’m reminded of the decades old Tootsie Pop commercial where a kid asks a series of talking animals, “How many licks does it take to get to the Tootsie Roll center of a Tootsie Pop?”

While Mr. Cow, Mr. Fox, and Mr. Turtle are all stumped, Mr. Owl tackles the question like a true scientist:

“A good question. Let’s find out. [Takes Tootsie pop and starts licking]. A One…A Two-hoo…A Three-hee. [Insert loud crunching sounds] A Three!”

The commercial ends with the narrator concluding that the world may never know how many licks it takes to get to the center (because Mr. Owl failed to complete his experiment…not a true scientist after all).

What do Tootsie Pops have to do with stem cell therapies?

I’m not saying that the Tootsie Pop question holds the same level of importance as the question of when scientists will develop a stem cell therapy that cures a disease, but I find it representative of the confusion and uncertainty that the general public has about when the “promise of stem cell research” will become a reality.

Let me explain…

Mr. Owl claims that it only takes three licks to get to the center of a Tootsie Pop, but three licks obviously aren’t enough to get through the hard candy exterior to the chewy tootsie center. According to the Tootsie “Scientific Endeavors” page, “at least three detailed scientific studies” determined that it takes between 144-411 licks to get to the center. My intuition is to go with the scientists, but depending on how the experiment was conducted or maybe the size of the tongue used, the final answer could vary.

Embryonic stem cells

Embryonic stem cells

For stem cell clinical trials, the situation is similar. The first clinical trial approved in the U.S. using human embryonic stem cells was in 2009. Since then, hundreds of clinical trials have been conducted globally using pluripotent – either embryonic or induced pluripotent stem cells (iPSCs) – or adult stem cells. But so far, none have made their way routinely to patients outside of a clinical trial setting in the U.S., (although a few stem cell-based products have been approved in other countries), and it’s unclear how many more trials it will take to get to this point.

Part of this murkiness is because we’re still in the early days of stem cell research: human embryonic stem cells were first isolated by James Thomson in 1998, and iPSCs weren’t discovered by Shinya Yamanaka until 2006. Scientists need more time to conduct preclinical research to understand how these stem cells can be best used to treat certain diseases and what stem cells will do when transplanted into patients.

Another other issue is that the U.S. Food and Drug Administration (FDA) has only approved one stem cell therapy – cord blood stem cell transplantation – for commercial use in 2011 and none since then. A big debate is currently ongoing about whether the regulatory landscape needs to change so that stem cell treatments that show promise in trials can get to patients who desperately need them.

Hopefully soon, the FDA will adopt a more efficient strategy for approving stem cell therapies that still keeps patient safety at the forefront. Otherwise it could take a lot longer for newer stem cell technologies like iPSCs to make their way to the clinic (although we’ve seen some encouraging preliminary results using iPSC-based therapy in clinical trials for blindness).

Trial, trial, trial again

So how many clinical trials will it take for a stem cell therapy to succeed sufficiently to gain approval and when will that happen?

Unfortunately, we don’t know the answers to these questions, but we do know that scientists need to continue to develop and test new stem cell treatments in human trials if we want to see any progress.

At CIRM, we are currently funding 16 clinical trials involving stem cell therapies for cancer, heart failure, diabetes, spinal cord injury and other diseases. But we need to fund more trials to increase the odds that some will make it through the gauntlet and prove both safe and effective at treating patients. Our goal now is to fund 50 clinical trials in the next five years. It’s an aggressive plan, but one we feel will hopefully take stem cell therapies from promise to reality.

We also know that CIRM is a soldier in a large army of funding agencies, universities, companies, and scientists around the world battling against time to develop stem cell therapies that could help patients in their lifetimes. And with this stem cell army, we believe we’re getting closer to the chewy center of the Tootsie pop, or in this case, an approved stem cell therapy for patients desperate for a cure.

This blog was written as part of the CCRM Signals iPSC anniversary blog carnival. Please click here to read what other bloggers have to say about the future of stem cells and regenerative medicine.

Sleep inducing hormone puts breast cancer cells to rest  

It’s pretty easy to connect the dots between a lack of sleep and an increased risk of a deadly car crash. But what about an increased risk of cancer? A 2012 study of 101 women newly diagnosed with breast cancer found that those with inadequate sleep were more likely to have more aggressive tumors. Though the results of this survey were statistically significant, the biological connection between sleep and breast cancer is not well understood.

melatonin

Melatonin, the sleep hormone, may help fight cancer. Image Credit

Now, a report in Genes and Cancer by a Michigan State University research team shows that the interplay between melatonin, a hormone involved in sleep-wake cycles, and breast cancer stem cells may provide an explanation. And, more importantly, the study points to melatonin’s potential use as a cancer therapeutic.

Mammospheres: cancer in a more natural environment
To carry out their lab experiments, the researchers grew breast cancer cells into three-dimensional aggregates, called mammospheres, that resemble the tumor cell composition seen in an actual tumor in the body. This cell mix includes breast cancer stem cells which are thought to drive the uncontrolled tumor growth and reccurrence. David Arnosti, a MSU professor and co-author on the study, used a helpful analogy in a university press release to explain the importance of using the mammosphere technique:

“You can watch bears in the zoo, but you only understand bear behavior by seeing them in the wild. Similarly, understanding the expression of genes in their natural environment reveals how they interact in disease settings. That’s what is so special about this work.”

 

Melatonin fighting cancer cells via their stem cell-like properties
The cancer cells used in this study are also categorized as so-called estrogen receptor (ER) -positive cells. This classification means that the cancer growth is largely stimulated by the hormone estrogen.  The first round of experiments analyzed melatonin’s effects on estrogen’s ability to increase the growth and size of the mammospheres. The team also tested Bisphenol A (BPA), a chemical used in the plastics industry that mimics estrogen’s effects. While estrogen or BPA alone caused a large increase in mammosphere size and number, addition of melatonin stunted these effects.

Next, the team went deeper and looked at melatonin’s impact from a genes and proteins perspective. Estrogen is a steroid hormone that acts by passing through the cell wall and binding to the estrogen receptor inside the cell. Once bound by estrogen, the receptor travels to a cell’s nucleus and binds particular regions of DNA which can activate genes. One of those activated genes is responsible for producing OCT4, a protein that plays a critical role in a stem cell’s ability to indefinitely makes copies of itself and to maintain its unspecialized, stem cell state. This cellular pathway is how estrogen helps drives the growth of ER-positive breast cancer cells. The researchers showed that estrogen- and BPA-stimulated binding of the estrogen receptor to the OCT4 gene in the mammospheres was inhibited when melatonin was added to the cells.

Melatonin: putting cancer stems to bed?
Putting these observations together, melatonin appears to suppress breast tumor growth by directing inhibiting genes responsible for driving the stem cell-like properties of the breast cancer stem cells within the mammosphere. Melatonin is produced by the brain’s pineal gland which is only active at night. Once released, melatonin helps induce sleep. So a disrupted sleep pattern, like insomnia, would reduce melatonin levels and as a consequence the block on estrogen driven cancer growth is removed. ­

James Trosko, whose MSU lab perfected the mammosphere technique, sees these breast cancer results in a larger perspective:

“This work establishes the principal by which cancer stem cell growth may be regulated by natural hormones, and provides an important new technique to screen chemicals for cancer-promoting effects, as well as identify potential new drugs for use in the clinic.”

 

Keep in mind that these are very preliminary studies and more work is needed before a potential clinical application sees the light of day. In the meantime, have a good day and get a good night’s sleep.

 

 

New approach could help turn back the clock and reverse damage for stroke patients

stroke

Stroke: courtesy WebMD

Stroke is the leading cause of serious, long-term disability in the US. Every year almost 800,000 people suffer from a stroke. The impact on their lives, and the lives of those around them can be devastating.

Right now the only treatment approved by the US Food and Drug Administration (FDA) is tissue plasminogen activator or tPA. This helps dissolve the blood clot causing most strokes and restores blood flow to the brain. However, to be fully effective this has to be administered within about 3-4 hours after the stroke. Many people are unable to get to the hospital in time and as a result suffer long-term damage, damage that for most people has been permanent.

But now a new study in Nature Medicine shows that might not be the case, and that this damage could even be reversible.

The research, done by a team at the University of Southern California (USC) uses a one-two punch combination of stem cells and a protein that helps those cells turn into neurons, the cells in the brain damaged by a stroke.

First, the researchers induced a stroke in mice and then transplanted human neural stem cells alongside the damaged brain tissue. They then added in a dose of the protein 3K3A-APC or a placebo.

hey found that mice treated with 3K3A-APC had 16 times more human stem-cell derived neurons than the mice treated with the placebo. Those neurons weren’t just sitting around doing nothing. USC’s Berislav Zlokovic, senior author of the paper, says they were actively repairing the stroke-induced damage.

“We showed that 3K3A-APC helps the grafted stem cells convert into neurons and make structural and functional connections with the host’s nervous system. No one in the stroke field has ever shown this, so I believe this is going to be the gold standard for future studies. Functional deficits after five weeks of stroke were minimized, and the mice were almost back to normal in terms of motor and sensorimotor functions. Synapses formed between transplanted cells and host cells, so there is functional activation and cooperation of transplanted cells in the host circuitry.”

The researchers wanted to make sure the transplanted cell-3K3A-ACP combination was really the cause of the improvement in the mice so they then used what’s called an “assassin toxin” to kill the neurons they had created. That reversed the improvements in the treated mice, leaving them comparable to the untreated mice. All this suggests the neurons had become an integral part of the mouse’s brain.

So how might this benefit people? You may remember that earlier this summer Stanford researchers produced a paper showing they had helped some 18 stroke patients, by injecting stem cells from donor bone marrow into their brain. The improvements were significant, including in at least one case regaining the ability to walk. We blogged about that work here

In that study, however, the cells did not become neurons nor did they seem to remain in the brain for an extended period. It’s hoped this new work can build on that by giving researchers an additional tool, the 3K3A-ACP protein, to help the transplanted cells convert to neurons and become integrated into the brain.

One of the other advantages of using this protein is that it has already been approved by the FDA for use in people who have experienced an ischemic stroke, which accounts for about 87 percent of all strokes.

The USC team now hope to get approval from the FDA to see if they can replicate their experiences in mice in people, through a Phase 2 clinical trial.

 

 

 

 

 

 

 

Stem cell stories that caught our eye: Zika virus and adult brains, a step toward precision medicine and source of blood stem cells

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

Zika virus and the adult brain.  While almost all the press attention for the Zika virus has centered on pregnant women and the devastating impact the virus can have on their developing babies, a few stories have noted that while most adults don’t know they have been infected, a few do. The one significant impact seen is a relatively rare incidence of Guillain-Barre Syndrome, which can cause temporary partial paralysis. That has triggered a few researchers to look for other impacts in adults infected with the mosquito-borne virus.

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Researchers trying to understand why the virus leads to the underdeveloped brains known as microcephaly, in infants have shown the virus does its nasty work at the level of the nerve stem cell. Although adults have far fewer nerve stem cells than a developing fetus, they do have some. So a team at Rockefeller University in New York and the La Jolla Institute for Allergy and Immunology decided to look for any effects of infection on adult nerve stem cells in mice.  They published the work this week in the journal Cell Stem Cell and report a dramatic reduction in adult nerve stem cells in infected mice.

“Adult neurogenesis is implicated in learning and memory,” said the La Jolla Institute’s Sujan Shresta in a press release from the journal. “We don’t know what this would mean in terms of human diseases, or if cognitive behaviors of an individual could be impacted after infection.”

Mice are normally resistant to Zika infection, so the researchers first had to genetically engineer mice to be susceptible to infection. That means several layer of caveats and more research are needed before any assertions about adult impact of Zika infection in humans.

This work captured considerable press attention including in Buzzfeed, NBC and USNews and World Report.

 

Heart felt precision medicine.  With the boost of a special initiative launched by the Obama administration, precision medicine is becoming all the rage, at least as a goal. While a few cancer therapies currently use this concept of matching therapies to a specific patient’s genetic makeup, few doctors outside of oncology can turn to similarly precise therapies.

Cardio cells image

Heart muscle cells

Work from a CIRM-funded team at Stanford has moved other doctors a bit closer to this goal for heart disease. But this research will not lead to treating it, rather it could allow doctors to prevent therapies used for other diseases from causing heart disease. Joseph Wu and his team have made two discoveries that help validate the use of the iPS reprogramming technique to make patient-specific stem cells and then mature them into heart muscle cells and see how those cells react to specific drugs.

“Thirty percent of drugs in clinical trials are eventually withdrawn due to safety concerns, which often involve adverse cardiac effects,” said Wu in a press release picked up by ScienceNewsLine. “This study shows that these cells serve as a functional readout to predict how a patient’s heart might respond to particular drug treatments and identify those who should avoid certain treatments.”

 

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Joseph Wu

There has always been some concern that the genetic manipulation used to create iPS cells changes the genetics of any adult tissue you make from the cells. So, with samples from three patients who were undergoing heart biopsy or transplant, which allowed harvesting mature heart muscle, the team compared the genetic signature of the adult heart muscle and that of heart muscle created from iPS cells.  They found no significant differences.

With skin samples from another seven subjects they created iPS cells and then heart muscle and compared their genetic signatures. The found some slight difference in all seven, but dramatic differences in one. That difference was in a genetic pathway involved in the inner workings of heart muscle. When they treated those cells with a diabetes drug that had been linked to heart problems, the cells reacted quite differently from the cells of the other six subjects treated with the same drug. With this knowledge a doctor could avoid ever choosing to put that particular patient on that diabetes drug.

 

Source of blood stem cells matters.  For years, bone marrow transplant—the one currently routine stem cell therapy—required digging into someone bone to harvest the stem cells. Over the decades that the procedure has been saving thousands of lives doctors have found less invasive methods to get the stem cells using drugs to “mobilize” the marrow stem cells and get them to move into the blood stream where they can be harvested.

While stem cell donors often find the new procedure a vast improvement, no one had done a thorough review of the outcomes for patients who receive stem cells gathered by the different procedures until a paper this week from the Fred Hutchison Cancer Research Center in Seattle. While they did not find any differences in overall life expectancy, they found vastly different outcomes in quality of life including psychological wellbeing and ability to return to work.

The Hutchison team attributed most of this difference to a lower rate of Graft Versus Host Disease (GVHD), possibly the most dangerous side effect of the procedure, which occurs when the stem cell transplant also contains adult immune system cells from the donor and those “graft” cells attack the “host,” the patient. It makes sense that when you harvest cells from the blood stream you would be more likely to also capture mature immune cells than when you harvest cells from marrow. And GVHD can be extremely painful, debilitating, and often deadly.

Stephanie Lee Hutchison

Stephanie Lee

“When both your disease and the recommended treatment are life-threatening, I don’t think people are necessarily asking ‘which treatment is going to give me better quality of life years from now?'” said Stephanie Lee the lead author in a press release from the cancer center. “Yet, if you’re going to make it through, as many patients do, you want to do it with good quality of life. That’s the whole point of having the transplant.”

Better, Faster Quality Control for Stem Cell-Based Therapies

“Based”.

It’s a pretty boring word but I make sure to include it when writing about the development of stem cell therapies, as in: “Asterias Biotherapeutics is testing an embryonic stem cell-based treatment for spinal cord injury”. It’s a key word here because no legitimate clinic would transplant embryonic stem cells (ESCs) or induced pluripotent stem cells (iPSCs) directly into a patient. The ability of these cells to make unlimited copies of themselves is great for growing them in the lab; but in the body, that same property presents a very real risk of tumor formation. Instead, ESCs and iPSCs are merely the base material from which specialized cells are matured from for the many promising therapies being developed for clinical trials.

To ensure safety to patients, minimizing the number of these potentially cancer-causing pluripotent stem cells still lingering in a cell therapy product is one of the main safety concerns of the Food and Drug Administration (FDA), the U.S. federal agency that approves therapies for clinical trials. So during therapy development, researchers run assays, or tests, to detect how many ESCs or iPSCs remain in their cell product and if they can form tumors.

In a paper published yesterday in Biomaterials, an Emory University research team reported on the development of a new technique that is several thousand-fold (!!!) higher in sensitivity than current assays and could be a game-changer for the quality control of stem cell-based therapies (also see an Emory U. blog about the study).

Surface-enhanced Raman Scattering Assay: it’s one in a million

SERS-schematic

Illustrated overview of the SERS assay workflow (Image: Biomaterials)

In the technique, called a surface-enhanced Raman scattering (SERS) assay, gold nanoparticles are attached to proteins, called antibodies, that specifically bind to the surface of stem cells. These antibody-nanoparticles are mixed with a preparation of the cell product. A laser is then directed at the cells and a device, called a spectrometer, measures the resulting light scatter which ultimately can be converted into the number of stem cells in the cell mix.

Incredibly, this assay can detect one stem cell out of one million specialized cells making it well suited for testing clinical grade cell therapy products. In comparison, the current flow cytometry technique which uses fluorescently tagged antibodies, can spot 1 stem cell in about 1000 cells.

Another current way to detect stem cells in a cell product is through the so-called teratoma assay. In this test, a mouse is injected with the cell therapy and observed for about three months to see if any teratomas, or tumors, form from residual stem cells. While this technique is a more direct safety test, it’s very costly, time-consuming, and impractical for testing very large doses of cell therapies. As the authors mention in the publication, the SERS technique could help overcome the limitations of both the teratoma and flow cytometry assays:

“Because of their remarkable sensitivity, these SERS assays may facilitate safety assessment of cell preparations for transplantations that require a large quantity of cells, which is unachievable using flow cytometry or the teratoma assay in mice. In addition, these assays are cost-effective, easy to use, and can be done within an hour, which is much faster than the traditional teratoma assay.”

“Faster”. Now that’s a pretty exciting word I always like to include when writing about the development of stem cell therapies.

 

A look back at the last year – but with our eyes firmly on the future

Randy

CIRM President & CEO Randy Mills doesn’t want “good”, he wants “better”

Better.

With that single word Randy Mills, our President and CEO, starts and ends his letter in our 2015 Annual Report and lays out the simple principle that guides the way we work at CIRM.

Better.

But better what?

“Better infrastructure to translate early stage ideas into groundbreaking clinical trials. Better regulatory practices to advance promising stem cell treatments more efficiently. Better treatments for patients in need.”

“Better” is also the standard everyone at CIRM holds themselves to. Getting better at what we do so we can fulfill our mission of accelerating stem cell treatments to patients with unmet medical needs.

The 2015 Annual Report highlights the achievements of the last year, detailing how we invested $135 million in 47 different projects at all levels of research. How our Board unanimously passed our new Strategic Plan, laying out an ambitious series of goals for the next five years from funding 50 new clinical trials, to creating a new regulatory process for stem cell therapies.

Snapshot of CIRM's 2015 Funding

The report offers a snapshot of where our money has gone this year, and how much we have left. It breaks down what percentage of our funding has gone to different diseases and how much we have spent on administration.

Jonathan Thomas, the Chair of our Board, takes a look back at where we started, 10 years ago, comparing what we did then (16 awards for a total of $12.5 million) to what we are doing today. His conclusion; we’re doing better.

But we still have a long way to go. And we are determined to get even better.

P.S. By the way we are changing the way we do our Annual Report. Our next one will come out on January 1, 2017. We figured it just made sense to take a look back at the last year as soon as the new year begins. It gives you a better (that word again) sense of what we did and where we  are heading. So look out for that, coming sooner than you think.

Here’s a new gene editing strategy to treat genetic blood disorders

If you’re taking a road trip across the country, you have a starting point and an ending point. How you go from point A to point B could be one of a million different routes, but the ultimate outcome is the same: reaching your final destination.

Yesterday scientists from St. Jude Children’s Research Hospital published exciting findings in the journal Nature Medicine on a new gene editing strategy that could offer a different route for treating genetic blood disorders such as sickle cell disease (SCD) and b-thalassemia.

The scientists used a gene editing tool called CRISPR. Unless you’ve been living under a rock, you’ve heard about CRISPR in the general media as the next, hot technology that could possibly help bring cures for serious diseases.

In simple terms, CRISPR acts as molecular scissors that facilitate cutting and pasting of DNA sequences at specific locations in the genome. For blood diseases like SCD and b-thalassemia, in which blood cells have abnormal hemoglobin, CRISPR gene editing offers ways to turn on and off genes that cause the clinical symptoms of these diseases.

Fetal vs. Adult hemoglobin

Before I get into the meat of this story, let’s take a moment to discuss hemoglobin. What is it? It’s a protein found in red blood cells that transports oxygen from the lungs to the rest of the body. Hemoglobin is made up of different subunits and the composition of these hemoglobin subunits change as newborns develop into adults.

0a448-sicklecellimage

Healthy red blood cell (left), sickle cell (right).

Fetal hemoglobin (HbF) is comprised of a and g subunits while adult hemoglobin (HbA) is typically comprised of a and b subunits. Patients with SCD and b-thalassemia typically have mutations in the b globin gene. In SCD, this causes blood cells to take on an unhealthy, sickle cell shape that can clog vessels and eventually cause premature death. In b-thalassemia, the b-globin gene isn’t synthesized into protein at the proper levels and patients suffer from anemia (low red blood cell count).

One way that scientists are attempting to combat the negative side effects of mutant HbF is to tip the scales towards maintaining expression of the fetal g-globin gene. The idea spawned from individuals with hereditary persistence of fetal hemoglobin (HPFH), a condition where the hemoglobin composition fails to transition from HbF to HbA, leaving high levels of HbF in adult blood. Individuals who have HPFH and are predisposed to SCD or b-thalassemia amazingly don’t have clinical symptoms, suggesting that HbF plays either a protective or therapeutic role.

The current study is taking advantage of this knowledge in their attempt to treat blood disorders. Mitchell Weiss, senior author on the study and chair of the St. Jude Department of Hematology, explained the thought process behind their study:

“It has been known for some time that individuals with genetic mutations that persistently elevate fetal hemoglobin are resistant to the symptoms of sickle cell disease and beta-thalassemia, genetic forms of severe anemia that are common in many regions of the world. We have found a way to use CRISPR gene editing to produce similar benefits.”

CRISPRing blood stem cells for therapeutic purposes

Weiss and colleagues engineered red blood cells to have elevated levels of HbF in hopes of preventing symptoms of SCD. They used CRISPR to create a small deletion in a sequence of DNA, called a promoter, that controls expression of the hemoglobin g subunit 1 (HBG1) gene. The deletion elevates the levels of HbF in blood cells and closely mimics genetic mutations found in HPFH patients.

Weiss further explained the genome editing process in a news release:

Mitchell Weiss

Mitchell Weiss

“Our work has identified a potential DNA target for genome editing-mediated therapy and offers proof-of-principle for a possible approach to treat sickle cell and beta-thalassemia. We have been able to snip that DNA target using CRISPR, remove a short segment in a “control section” of DNA that stimulates gamma-to-beta switching, and join the ends back up to produce sustained elevation of fetal hemoglobin levels in adult red blood cells.”

The scientists genetically modified hematopoietic stem cells and blood progenitor cells from healthy individuals to make sure that their CRISPR gene editing technique was successful. After modifying the stem cells, they matured them into red blood cells in the lab and observed that the levels of HbF increased from 5% to 20%.

Encouraged by these results, they tested the therapeutic potential of their CRISPR strategy on hematopoietic stem cells from three SCD patients. While 25% of unmodified SCD blood stem cells developed red blood cells with a sickle cell shape under low-oxygen conditions (to induce stress), CRISPR edited SCD stem cells generated way fewer sickle cells (~4%) and had a higher level of HbF expression.

Many routes, one destination

The authors concluded that their genome editing technique is successful at switching hemoglobin expression from the adult form back to the fetal form. With further studies and safety testing, this strategy could be one day be developed into a treatment for patients with SCD and b-thalassemia

But the authors were also humble in their findings and admitted that there are many different genome editing strategies or routes for developing therapies for inherited blood diseases.

“Our results represent an additional approach to these existing innovative strategies and compare favorably in terms of the levels of fetal hemoglobin that are produced by our experimental system.”

My personal opinion is the more strategies thrown into the pipeline the better. As things go in science, many of these strategies won’t be successful in reaching the final destination of curing one of these diseases, but with more shots on goal, our chances of developing a treatment that works there are a lot higher.


Related links:

Dr. Deborah Deas joins CIRM Board

Deborah Deas has been appointed dean of the UCR School of Medicine

Deborah Deas, MD, MPH, UCR School of Medicine

Dr. Deborah Deas is clearly not someone who opts for the quiet life. If she were, she would have stayed home in Adams Run, the tiny town in rural South Carolina where she was born.

The website, NeighborhoodScout.com describes Adams Run (current population 1,492) as:

“One of the quietest neighborhoods in America. When you are here, you will find it to be very quiet. If quiet and peaceful are your cup of tea, you may have found a great place for you.”

Dr. Deas obviously wasn’t a tea drinker because she packed her bags and went off to college in Charleston. That was the first step on a journey that led the self-described “farmer’s daughter” to become an MD, then an MPH (Masters in Public Health), before assuming a leadership role at the Medical University of South Carolina (MUSC). More recently she headed to California’s Inland Empire where she was named the Dean and CEO for Clinical Affairs of the UC Riverside School of Medicine.

And now we are delighted to add to that list of achievements by announcing she is the newest member of the CIRM Board.

She was appointed to the Board by state Treasurer John Chiang who praised her for her:

“Passion to improve  health for underserved populations and to diversify the health care work force. She is committed to making the benefits of advanced medicine available to all Californians.”

 

In a news release our CIRM Board Chair, Jonathan Thomas, was equally fulsome in his praise and welcome to Dr. Deas.

 “We are delighted to have someone with Dr. Deas’ broad experience and expertise join us at CIRM. Her medical background and her commitment to diversity and inclusion are important qualities to bring to a Board that is striving to deliver stem cell treatments to patients, and to reflect the diversity of California.”

To say that she brings a broad array of skills and experience to the Board is something of an understatement. She is board certified in adult psychiatry, child and adolescent psychiatry and addiction psychiatry, and is widely regarded as a national leader in research into youth binge drinking, adolescent nicotine dependence, marijuana use and panic disorder, and pharmaceutical treatment of pediatric depressive disorder.

As if that wasn’t enough, she has also been named as one of the best doctors in the U.S. by U.S. News & World Report for the last eight years.

But the road to UC Riverside and CIRM hasn’t always been easy. In a first person perspective in Psychiatric News.

she said that at MUSC she was just one of two African Americans among the 500 residents in training:

“It was not uncommon for me to be mistaken by many for a social worker, a secretary, or a ward clerk despite wearing my white coat with Deborah Deas, M.D., written on it. This mistake was even made by some of my M.D. peers. I found that the best response was to ask, “And just why do you think I am a social worker?”

She says the lessons she learned from her parents and grandparents helped sustain her:

“They emphasized the importance of setting goals and keeping your eyes on the prize. Service was important, and the ways that one could serve were numerous. The notion that one should learn from others, as well as teach others, was as common as baked bread. My parents instilled in me that education is the key to a fruitful future and that it is something no one can take away from you.”

Her boss at UC Riverside, the Provost and Executive Vice Chancellor, Paul D’Anieri said Dr. Deas is a great addition to the CIRM Board:

“Deborah is a public servant at heart. Her own values and goals to help underserved patient populations align with the goals of CIRM to revolutionize medicine and bring new, innovative treatments to all patients who can benefit. I am confident that Dr. Deas’ service will have a lasting positive impact for CIRM and for the people of California.”

Dr. Deas ends her article in Psychiatric News saying:

“The farmer’s daughter has come a long way. I have stood on the shoulders of many, pushing forward with an abiding faith that there was nothing that I could not accomplish.”

She has indeed come a long way. We look forward to being a part of the next stage of her journey, and to her joining CIRM and bringing that “abiding faith” to our work.

 

 

Stem cell stories that caught our eye: better bone marrow transplants, turbo charging anti-inflammatory stem cells and Zika’s weapons

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

Three steps to better BMT.  Bone marrow stem cell transplants (BMT) save the lives of many thousands of patients every year, but they also kill a significant number of the blood stem cell transplantcancer and immune disorder patients the procedure is intended to save. In order to make room in the bone marrow for new blood-forming stem cells, you first have to get rid of most of the stem cells already there, and the radiation and chemotherapy to do this proves too toxic for some patients. Also, donor marrow can contain immune cells from the donor that can attack the recipient causing Graft Versus Host Disease (GVHD), which can also be fatal.

Add this all together and physicians tend to save BMT for the patients with the most life threatening forms of the diseases.  A CIRM-funded team at Stanford has developed a three-step process that seems to dramatically reduce all those risks potentially opening up the procedure to less-sick patients including patients with life-altering, but not life-threatening, autoimmune diseases such as lupus and less severe forms of multiple sclerosis.

Experimenting in mice, they first used an antibody that attaches to a marker on blood stem cells called c-kit. But by itself that antibody could not get rid of enough of the stem cells. So, they added a second agent that blocked another protein, CD47, on the surface of blood stem cells. With that protein blocked, the animals own immune cells called macrophages, could destroy the blood stem cells. Then to make the donor cells safer, they used a technology they had developed many years ago to remove any straggler immune cells from the donor stem cells, thus drastically eliminating the chances for GVHD.

judith shizuru

Shizuru

“If it works in humans like it did in mice, we would expect that the risk of death from blood stem cell transplant would drop from 20 percent to effectively zero,” said senior author Judith Shizuru in a university press release posted by HealthCanal.

She went on to compare blood stem cell transplants to planting a new field of crops saying they were looking for a better way to first clear the field for planting and then a better way to do the planting. CIRM funded the team to develop the method for use with Severe Combined Immune Deficiency (SCID). The team published the current mouse study in the journal Science Translational Medicine.

 

Building a better anti-inflammatory stem cell.  Of the more than 700 stem cell therapy clinical trials underway around the world, more than half use the type of stem cell called a mesenchymal stem cell (MSC) found in bone marrow and fat—in marrow it resides alongside the blood-forming stem cells. Some of those trials are tapping into MSC’s ability to build bone, cartilage and blood vessels, but many are counting on their strong anti-inflammatory properties to fight autoimmune diseases.

When MSCs find themselves in an environment with pro-inflammatory proteins they respond by producing anti-inflammatory proteins. To enhance that effect some teams have bathed their MSC’s in pro-inflammatory proteins before injecting them into patients, but the effect of those proteins wears off quickly. So, a team led by CIRM-funded researcher Todd McDevitt at the Gladstone Institutes in San Francisco has bioengineered a way to make the effect long term.

McDevitt,-Todd-14

Gladstone used a CIRM Research Leadership award to recruit McDevitt from Georgia Tech

They loaded the pro-inflammatory proteins onto sugar-based particles that they imbedded in the middle of clusters of MSCs. The bioengineered complex slowly releases the cues to the MSCs and they in turn produced the desired anti-inflammatory proteins in greater quantities and much longer than in any other experiment.

 “A patient taking anti-inflammatory medication may not have high enough levels of inflammation to trigger the cells. We engineered the MSCs to ensure that they are consistently activated, so they can reliably dampen the immune response for longer,” said McDevitt in an institute press release.

The team published their research in Stem Cells Translational Medicine.

 

Stem cells used to identify Zika’s weapon.  It has been difficult for researchers to think about how to stop the Zika virus’ havoc on fetal brains without knowing how the virus does

Zika Virus

its evil deed. Now, a team at the University of Southern California (USC) has used fetal stem cells to discover two proteins that seem to be Zika’s key weapons.

Viruses often hijack our normal cell processes to enhance their ability to multiply and at the same time do harm to the host. In this case, the two proteins named NS4A and NS4B play key roles in the cell path for normal cell growth and disposal of damaged cells. When exploited by the virus, the two proteins result in cells being destroyed and not replaced.

“Those two viral proteins are ultimately the target for therapy development,” said USC’s Jae Jung in an article posted by Kaiser Health News.

As is typical with this news source, the author goes on to provide considerable high quality background about the Zika outbreak and efforts to find a vaccine or therapy, in this case quoting experts from Texas Children’s Hospital and Baylor.

 

Cloning fact timeline.  With the 20th anniversary last month of the birth of Dolly the sheep, the first cloned mammal, cloning seems to be much in discussion these days. So for

dolly-the-sheep

science nerds who like to keep back up facts handy CNN published a timeline of key events starting with the 1952 Nobel-winning discovery that you could replace the nucleus of a frog’s egg with the nucleus from another cell and still get the egg to develop into a tadpole. And 22 events later, it ends in 2014 with the first use of using cloning techniques to create stem cells that matched an adult.