Stanford and University of Tokyo researchers crack the code for blood stem cells

Blood stem cells grown in lab

Blood stem cells offer promise for a variety of immune and blood related disorders such as sickle cell disease and leukemia. Like other stem cells, blood stem cells have the ability to generate additional blood stem cells in a process called self-renewal. Additionally, they are able to generate blood cells in a process called differentiation. These newly generated blood cells have the potential to be utilized for transplantations and gene therapies.

However, two limitations have hindered the progress made in this field. One problem relates to the amount of blood stem cells needed to make a potential transplantation or gene therapy viable. Unfortunately, it has been challenging to isolate and grow blood stem cells in large quantity needed for these approaches. A part of this reason relates to getting the blood stem cells to self-renew rather than differentiate.

The second problem involves the existing blood stem cells in the patient’s body prior to transplantation. In order for the procedure to work, the patient’s own blood stem cells must be eliminated to make space for the transplanted blood stem cells. This is done through a process known as conditioning, which typically involves chemotherapy and/or radiation. Unfortunately, chemotherapy and radiation can cause life-threatening side effects due to its toxicity, particularly in pediatric patients, such as growth retardation, infertility and secondary cancer in later life. Very sick or elderly patients are unable to tolerate this conditioning process, making them ineligible for transplants.

A CIRM funded study by a team at Stanford and the University of Tokyo has unlocked the code related to the generation of blood stem cells.

The collaborative team was able to modify the components used to grow blood stem cells. By making these modifications, which effects the growth and physical conditions of blood stem cells, the researchers have shown for the first time that it’s possible to get blood stem cells from mice to renew themselves hundreds or even thousands of times within a period of just 28 days. 

Furthermore, the team showed that when they transplanted the newly grown cells into mice that had not undergone conditioning, the donor cells had engrafted and remained functional.

The team also found that gene editing technology such as CRISPR could be used while growing an adequate supply of blood stem cells for transplantation. This opens the possibility of obtaining a patient’s own blood stem cells, correcting the problematic gene, and reintroducing these back to the patient.

The complete study was published in Nature.

In a news release, Dr. Hiromitsu Nakauchi, a senior author of the study, is quoted as saying,

“For 50 years, researchers from laboratories around the world have been seeking ways to grow these cells to large numbers. Now we’ve identified a set of conditions that allows these cells to expand in number as much as 900-fold in just one month. We believe this approach could transform how [blood] stem cell transplants and gene therapy are performed in humans.” 

Stem Cell Agency Board Approves New Clinical Trial for Type 1 Diabetes

Dr. Peter Stock at the capitol in Sacramento in May 2016.
Photo courtesy of Steve German.

Today the governing Board of the California Institute for Regenerative Medicine (CIRM) awarded $11.08 Million to Dr. Peter Stock at the University of California San Francisco (UCSF) to conduct a clinical trial for treatment of Type 1 Diabetes (T1D).

The award brings the total number of CIRM funded clinical trials to 54. 

T1D is a chronic autoimmune disease that affects approximately 1.25 million Americans, with 40,000 new diagnoses each year.  T1D occurs as a result of the body’s immune system destroying its own pancreatic beta cells.  These cells are necessary to produce the vital hormone insulin, which regulates blood sugar levels in the body.  As a result of a lack of insulin, there is no blood sugar control in T1D patients, gradually causing disabling and life-threatening complications such as heart disease, nerve damage, and vision problems.

There is no cure for T1D.  Current treatments consist of blood sugar monitoring and multiple daily injections of insulin.  Transplantation of beta cells, contained in donor pancreatic islets, can reverse the symptoms of diabetes.  However, due to a poor islet survival rate, transplants require islets from multiple donors.  Furthermore, since islet cells are transplanted directly into the vessels that enter the liver, it is extremely difficult to monitor and retrieve these cells should the need arise. 

Dr. Stock’s clinical trial at UCSF aims to address these limitations.  The trial will be using parathyroid glands to aid in the success and viability of the transplant procedure.  Co-transplantation of islets and parathyroid glands, from the same donor, substantially increases beta cell survival, potentially enabling adequate long-term insulin production and removing the need for multiple donors.  Additionally, the co-transplantation will occur in the patient’s forearm, which allows for easier monitoring and improves the effectiveness and accessibility of islet transplants for patients.

“This team’s innovative approach to develop a definitive cell-based treatment for Type 1 Diabetes has the potential to address an unmet medical need that exists despite advancements in diabetes therapy.” says Maria T. Millan, M.D., the President and CEO of CIRM.  “The success of this clinical trial could enable the successful application of islet cell transplants but also of future stem-cell based approaches for diabetes.”

CIRM has funded three other clinical trials for T1D.  One of these was conducted by Caladrius Biosciences and two by ViaCyte, Inc.

How a see-through fish could one day lead to substitutes for bone marrow transplants

Human blood stem cells

For years researchers have struggled to create human blood stem cells in the lab. They have done it several times with animal models, but the human kind? Well, that’s proved a bit trickier. Now a CIRM-funded team at UC San Diego (UCSD) think they have cracked the code. And that would be great news for anyone who may ever need a bone marrow transplant.

Why are blood stem cells important? Well, they help create our red and white blood cells and platelets, critical elements in carrying oxygen to all our organs and fighting infections. They have also become one of the most important weapons we have to combat deadly diseases like leukemia and lymphoma. Unfortunately, today we depend on finding a perfect or near-perfect match to make bone marrow transplants as safe and effective as possible and without a perfect match many patients miss out. That’s why this news is so exciting.

Researchers at UCSD found that the process of creating new blood stem cells depends on the action of three molecules, not two as was previously thought.

Zebrafish

Here’s where it gets a bit complicated but stick with me. The team worked with zebrafish, which use the same method to create blood stem cells as people do but also have the advantage of being translucent, so you can watch what’s going on inside them as it happens.  They noticed that a molecule called Wnt9a touches down on a receptor called Fzd9b and brings along with it something called the epidermal growth factor receptor (EGFR). It’s the interaction of these three together that turns a stem cell into a blood cell.

In a news release, Stephanie Grainger, the first author of the study published in Nature Cell Biology, said this discovery could help lead to new ways to grow the cells in the lab.

“Previous attempts to develop blood stem cells in a laboratory dish have failed, and that may be in part because they didn’t take the interaction between EGFR and Wnt into account.”

If this new approach helps the team generate blood stem cells in the lab these could be used to create off-the-shelf blood stem cells, instead of bone marrow transplants, to treat people battling leukemia and/or lymphoma.

CIRM is also funding a number of other projects, several in clinical trials, that involve the use of blood stem cells. Those include treatments for: Beta Thalassemia; blood cancer; HIV/AIDS; and Severe Combined Immunodeficiency among others.

CIRM public events highlight uncertain future of stem cell research

When governments cut funding for scientific research the consequences can be swift, and painful. In Canada last week for example, the government of Ontario cut $5 million in annual funding for stem cell research, effectively ending a project developing a therapy to heal the damaged lungs of premature babies.

Here in the US the federal government is already placing restrictions on support for fetal tissue research and there is speculation embryonic stem cell research could be next. That’s why agencies like CIRM are so important. We don’t rely on a government giving us money every year. Instead, thanks to the voters of California, we have had a steady supply of funds to enable us to plan long-term and support multi-year projects.

But those funds are due to run out soon. We anticipate funding our last new awards this year and while we have enough money to continue supporting all the projects our Board has already approved, we won’t be able to take on any new projects. That’s bad news for the scientists and, ultimately, really bad for the patients who are in need of new treatments for currently incurable diseases.

We are going to talk about that in two upcoming events.

UC San Diego Sanford Stem Cell Clinical Center

The first is a patient advocate event at UC San Diego on Tuesday, May 28th from 12.30pm to 1.30pm. It’s free, there is parking and snacks and refreshments will be available.

This will feature UC San Diego’s Dr. Catriona Jamieson, CIRM’s President and CEO Dr. Maria Millan and CIRM Board member and Patient Advocate for Parkinson’s Disease, David Higgins PhD. The three will talk about the exciting progress being made at UC San Diego and other programs around California, but also the uncertain future and the impact that could have for the field as a whole.

Here’s a link to an Eventbrite page that has more information about the event and also a link to allow you to RSVP ahead of time.

For all of you who don’t live in the San Diego Area – or who do but can’t make it to the event – we are holding a similar discussion online on a special Facebook Live: Ask the Stem Cell Team About the Future of Stem Cell Research event on Thursday, May 30th from noon till 1pm PDT.

This also features Dr. Millan and Dr. Higgins, but it also features UC Davis stem cell scientist, CIRM-grantee and renowned blogger Paul Knoepfler PhD.

Each brings their own experience, expertise and perspective on the field and will discuss the impact that a reduction in funding for stem cell research would have, not just in the short term but in the long run.

Because we all have a stake in what happens, both events – whether it’s in person or online – include time for questions from you, the audience.

You can find our Facebook Live: Ask the Stem Cell Team About the Future of Stem Cell Research on our Facebook page at noon on May 30th PDT

Stories that caught our eye: FDA grants orphan drug status to CIRM-funded therapy; stunning discovery upends ideas of cell formation; and how tadpoles grow new tails

Gut busting discovery

Intestinal stem cells: Photo courtesy Klaus Kaestner, Penn Institute for Regenerative Medicine

It’s not often you read the word “sensational” in a news release about stem cells. But this week researchers at the University of Copenhagen released findings that are overturning long-held ideas about the development of cells in our stomachs. So perhaps calling it “sensational” is not too big a stretch.

In the past it was believed that the development of immature cells in our stomachs, before a baby is born, was predetermined, that the cells had some kind of innate sense of what they were going to become and when. Turns out that’s not the case. The researchers say it’s the cells’ environment that determines what they will become and that all cells in the fetus’ gut have the potential to turn into stem cells.

In the “sensational” news release lead author, Kim Jensen, says this finding could help in the development of new therapies.

“We used to believe that a cell’s potential for becoming a stem cell was predetermined, but our new results show that all immature cells have the same probability for becoming stem cells in the fully developed organ. In principle, it is simply a matter of being in the right place at the right time. Here signals from the cells’ surroundings determine their fate. If we are able to identify the signals that are necessary for the immature cell to develop into a stem cell, it will be easier for us to manipulate cells in the wanted direction’.

The study is published in the journal Nature.                             

A tale of a tail

African clawed frog tadpole: Photo courtesy Gary Nafis

It’s long been known that some lizards and other mammals can regrow severed limbs, but it hasn’t been clear how. Now scientists at the University of Cambridge in the UK have figured out what’s going on.

Using single-cell genomics the scientists were able to track which genes are turned on and off at particular times, allowing them to watch what happens inside the tail of the African clawed frog tadpole as it regenerates the damaged limb.

They found that the response was orchestrated by a group of skin cells they called Regeneration-Organizing Cells, or ROCs. Can Aztekin, one of the lead authors of the study in the journal Science, says seeing how ROCs work could lead to new ideas on how to stimulate similar regeneration in other mammals.

“It’s an astonishing process to watch unfold. After tail amputation, ROCs migrate from the body to the wound and secrete a cocktail of growth factors that coordinate the response of tissue precursor cells. These cells then work together to regenerate a tail of the right size, pattern and cell composition.”

Orphan Drug Designation for CIRM-funded therapy

Poseida Therapeutics got some good news recently about their CIRM-funded therapy for multiple myeloma. The US Food and Drug Administration (FDA) granted them orphan drug designation.

Orphan drug designation is given to therapies targeting rare diseases or disorders that affect fewer than 200,000 people in the U.S. It means the company may be eligible for grant funding toward clinical trial costs, tax advantages, FDA user-fee benefits and seven years of market exclusivity in the United States following marketing approval by the FDA.

CIRM’s President and CEO, Dr. Maria Millan, says the company is using a gene-modified cell therapy approach to help people who are not responding to traditional approaches.

“Poseida’s technology is seeking to destroy these cancerous myeloma cells with an immunotherapy approach that uses the patient’s own engineered immune system T cells to seek and destroy the myeloma cells.”

Poseida’s CEO, Eric Ostertag, said the designation is an important milestone for the company therapy which “has demonstrated outstanding potency, with strikingly low rates of toxicity in our phase 1 clinical trial. In fact, the FDA has approved fully outpatient dosing in our Phase 2 trial starting in the second quarter of 2019.”

Testing a drug is safe before you give it to a pregnant woman

Pregnant woman holding medicine.

When a doctor gives you a medication you like to think that it’s safe, that it has been tested to make sure it will do you some good or, at the very least, won’t do you any harm. That’s particularly true when the patient is a pregnant woman. You hope the medication won’t harm her or her unborn child. Now scientists in Switzerland have found a new way to do that that is faster and easier than previous methods, and it uses cell cultures instead of animals.

Right now, drugs that are intended for use in pregnant women have to undergo some pretty rigorous testing before they are approved. This involves lots of tests in the lab, and then in animals such as rats and rabbits. It’s time consuming, costly, and not always accurate because animals never quite mimic what happens in people.

In the past researchers tested new medications in the lab on so-called “embryoid bodies”. These are three-dimensional clumps of cells developed from embryonic stem cells from mice. The problem is that even when tested in this way the cells don’t always reflect what happens to a medication as it passes through the body. For example, some medications can seem fine on the surface but after they pass through the liver can take on toxic qualities. 

So, scientists at ETH Zurich in Basel, Switzerland, developed a better way to test for toxicity.

They took a cell-culture chip and created several compartments on it, in some they placed the embryoid bodies and in others they put microtissue samples from human livers.  The different compartments were connected so that fluid flowed freely from the embryoid bodies to the liver and vice versa.

In a news release, Julia Boos, a lead author of the study, says this better reflects what happens to a medication exposed to a human metabolism.

“We’re the first to directly combine liver and embryonic cells in a body-on-a-chip approach. Metabolites created by the liver cells – including metabolites that are stable for just a few minutes – can thus act directly on the embryonic cells. In contrast to tests on mice, in our test, the substances are metabolised by human liver cells – in other words, just as they would be in the human body when the medication is administered.”

To see if this worked in practice the researchers tested their approach on the chemotherapy drug cyclophosphamide, which is turned into a toxic substance after passing through the liver.

They compared results from testing cyclophosphamide with the new liver/embryoid body method to the older method. They found the new approach was far more sensitive and determined that a 400 percent lower concentration of cyclophosphamide was enough to pose a toxic threat.

The team now hope to refine the test even further so it can one day, hopefully, be applied to drug development on a large scale.

Their findings are published in the journal Advanced Science

Stem cell model reveals deeper understanding into “ALS resilient” neurons

A descriptive illustration of Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s Disease. Courtesy of ALS Foundation website.

Understanding the basic biology of how a cell functions can be crucial to being able to better understand a disease and unlock a potential approach for a treatment. Stem cells are unique in that they give scientists the opportunity to create a controlled environment of cells that might be otherwise difficult to study. Dr. Eva Hedlund and a team of researchers at the Karolinska Institute in Sweden utilize a stem cell model approach to uncover findings related to Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s Disease.

ALS is a progressive neurodegenerative disease that destroys motor neurons, a type of nerve cell, that are important for voluntary muscle movement. When motor neurons can no longer send signals to the muscles, the muscles begin to deteriorate, a process formally known as atrophy. The progressive atrophy leads to muscle paralysis, including those in the legs and feet, arms and hands, and those that control swallowing and breathing. It affects about 30,000 people in the United States alone, with 5,000 new cases diagnosed each year. There is currently no cure.

In a previous study, researchers at the Karolinska Institute were able to successfully create oculomotor neurons from embryonic stem cells. For reasons not yet fully understood, oculomotor neurons are “ALS resilient” and can survive all stages of the disease.

In the current study, published in Stem Cell Reports, Dr. Hedlund and her team found that the oculomotor neurons they generated appeared more resilient to ALS-like degeneration when compared to spinal cord motor neurons, something commonly observed in humans. Furthermore, they discovered that their “ALS resilient” neurons generated from stem cells activate a survival-enhancing signal known as Akt, which is common in oculomotor neurons in humans and could explain their resilience. These results could potentially aid in identifying genetic targets for treatments protecting sensitive neurons from the disease.

In a press release, Dr. Hedlund is quoted as saying,

“This cell culture system can help identify new genes contributing to the resilience in oculomotor neurons that could be used in gene therapy to strengthen sensitive motor neurons.”

CIRM is currently funding two clinical trials for ALS, one of which is being conducted by Cedars-Sinai Medical Center and the other by Brainstorm Cell Therapeutics. The latter of the trials is currently recruiting patients and information on how to enroll can be found here.

CIRM-funded study helps unlock some of the genetic secrets behind macular degeneration

Retina affected by age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of vision loss in people over 60. It affects 10 million Americans. That’s more than cataracts and glaucoma combined. The causes of AMD are not known but are believed to involve a mixture of hereditary and environmental factors. There is no treatment for it.

Now, in a CIRM-funded study, researchers at UC San Diego (UCSD) have used stem cells to help identify genetic elements that could provide some clues as to the cause, and maybe give some ideas on how to treat it.

Before we get into what the researchers did let’s take a look at what AMD does. At a basic level it attacks the retina, the thin layer of tissue that lines the back of the eye. The retina receives light, turns it into electrical signals and sends it to the brain which turns it into a visual image.

The disease destroys the macula, the part of the retina that controls our central vision. At first, sight becomes blurred or fuzzy but over time it progresses to the point where central vision is almost completely destroyed.

To try and understand why this happens the team at UCSD took skin samples from six people with AMD and, using the iPSC method, turned those cells into the kinds of cell found in the retina. Because these cells came from people who had AMD they now displayed the same characteristics as AMD-affected retinal cells. This allowed the researchers to create what is called a “disease-in-a-dish” model that allowed them to see, in real time, what is happening in AMD.

They were able to identify a genetic variant that reduces production of a protein called VEGFA, which is known to promote the growth of new blood vessels.

In a news release Kelly Frazer, director of the Institute for Genomic Medicine at UCSD and the lead author of the study, said the results were unexpected.

Kelly Frazer, PhD, UC San Diego

“We didn’t start with the VEGFA gene when we went looking for genetic causes of AMD. But we were surprised to find that with samples from just six people, this genetic variation clearly emerged as a causal factor.”

Frazer says this discovery, published in the journal Stem Cell Reports, could ultimately lead to new approaches to developing new treatments for AMD.

CIRM already funds one clinical trial-stage project targeting AMD.

3D brain model shows potential for treatment of hypoxic brain injuries in infants

Image of 3D brain cultures in the Sergiu Pasca lab.
Photo courtesy of Timothy Archibald.

A baby’s time in the womb is one of the most crucial periods in terms of its development. The average length of gestation, which is defined as the amount of time in the womb from conception to birth, is approximately 40 weeks. Unfortunately, for reasons not yet fully understood, there are times that babies are born prematurely, which can lead to problems.

These infants can have underdeveloped portions of the brain, such as the cerebral cortex, which is responsible for advanced brain functions, including cognition, speech, and the processing of sensory and motor information. The brains of premature infants can be so underdeveloped that they are unable to control breathing. This, in combination with underdeveloped lungs, can lower oxygen levels in the blood, which can lead to hypoxic, or low oxygen related, brain injuries.

In a previous study, doctors Anca and Sergiu Pasca and their colleagues at Stanford developed a technique to create a 3D brain that mimics structural and functional aspects of the developing human brain.

Using this same technique, in a new study with the aid of CIRM funding, the team grew a 3D brain that contained cells and genes similar to the human brain midway through the gestational period. They then exposed this 3D brain to low oxygen levels for 48 hours, restored the oxygen level after this time period, and observed any changes.

It was found that progenitor cells in a region known as the subventricular zone, a region that is critical in the growth of the human cortex, are affected. Progenitor cells are “stem cell like” cells that give rise to mature brain cells such as neurons. They also found that the progenitor cells transitioned from “growth” mode to “survival” mode, causing them to turn into neurons sooner than normal, which leads to fewer neurons in the brain and underdevelopment.

In a press release, Dr. Anca Pasca is quoted as saying,

“In the past 20 years, we’ve made a lot of progress in keeping extremely premature babies alive, but 70% to 80% of them have poor neurodevelopmental outcomes.”

The team then tested a small molecule to see if it could potentially reverse this response to low oxygen levels by keeping the progenitor cells in “growth” mode. The results of this are promising and Dr. Sergiu Pasca is quoted as saying,

“It’s exciting because our findings tell us that pharmacologically manipulating this pathway could interfere with hypoxic injury to the brain, and potentially help with preventing damage.”

The complete findings of this study were published in Nature.

The Past, the Present, and the Uncertain Future of Stem Cell Research

Ronnie, a boy who was born without a functioning immune system but who is thriving today because of CIRM funded research

When CIRM was created in 2004 the field of stem cell research was still very much in its infancy. Fast forward 15 years and it’s moving ahead at a rapid pace, probably faster than most scientists would have predicted. How fast? Find out for yourself at a free public event at UC San Diego on May 28th from 12.30 to 1.30p.

In the last 15 years CIRM has funded 53 clinical trials in everything from heart disease and stroke, to spinal cord injury, vision loss, sickle cell disease and HIV/AIDS.

UCSD was one of the first medical centers chosen to host a CIRM Alpha Stem Cell Clinic – a specialist center with the experience and expertise to deliver stem cell therapies to patients – and to date is running more than a dozen clinical trials for breast cancer, heart failure, leukemia and chronic lower back pain.

Clearly progress is being made. But the field is also facing some challenges. Funding at the federal level for stem cell research is under threat, and CIRM is entering what could be its final phase. We have enough money left to fund new projects through this year (and these are multi-year projects so they will run into 2021 or 2022) but unless there is a new round of funding we will slowly disappear. And with us, may also disappear the hopes of some of the most promising projects underway.

If CIRM goes, then projects that we have supported and nurtured through different phases of research may struggle to make it into a clinical trial because they can’t get the necessary funding.

Clearly this is a pivotal time in the field.

We will discuss all this, the past, the present and the uncertain future of stem cell research at the meeting at UC San Diego on May 28th. The doors will open at noon for registration (snacks and light refreshments will also be available) and the program runs from 12.30p to 1.30p.

The speakers are:

  • Dr. Catriona Jamieson, Director of the UC San Diego Health CIRM Alpha Stem Cell Clinic and Sanford Stem Cell Clinical Center.
  • Dr. Maria Millan, President and CEO of CIRM
  • Dr. David Higgins, CIRM Board member and Patient Advocate for Parkinson’s Disease.

And of course, we want to hear from you, so we’ll leave plenty of time for questions.

Free parking is available.

Go here for more information about the event and how you can register

Free free to share this with anyone you think might be interested in joining us and we look forward to seeing you there.