Organoids revolutionize approach to studying a variety of diseases

Organoids

There are limitations to studying cells under a microscope. To understand some of the more complex processes, it is critical to see how these cells behave in an environment that is similar to conditions in the body. The production of organoids has revolutionized this approach.

Organoids are three-dimensional structures derived from stem cells that have similar characteristics of an actual organ. There have been several studies recently published that have used this approach to understand a wide scope of different areas.

In one such instance, researchers at The University of Cambridge were able to grow a “mini-brain” from human stem cells. To demonstrate that this organoid had functional capabilities similar to that of an actual brain, the researchers hooked it up to a mouse spinal cord and surrounding muscle. What they found was remarkable– the “mini-brain” sent electrial signals to the spinal cord that made the surrounding muscles twitch. This model could pave the way for studying neurodegenerative diseases such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS).

Spinal muscular atrophy

Speaking of SMA, researchers in Singapore have used organoids to come up with some findings that might be able to help people battling the condition.

SMA is a neurodegenerative disease caused by a protein deficiency that results in nerve degeneration, paralysis and even premature death. The fact that it mainly affects children makes it even worse. Not much is known how SMA develops and even less how to treat or prevent it.

That’s where the research from the A*STAR’s Institute of Molecular and Cell Biology (IMCB) comes in. Using the iPSC method they turned tissue samples from healthy people and people with SMA into spinal organoids.

They then compared the way the cells developed in the organoids and found that the motor nerve cells from healthy people were fully formed by day 35. However, the cells from people with SMA started to degenerate before they got to that point.

They also found that the protein problem that causes SMA to develop did so by causing the motor nerve cells to divide, something they don’t normally do. So, by blocking the mechanism that caused the cells to divide they were able to prevent the cells from dying.

In an article in Science and Technology Research News lead researcher Shi-Yan Ng said this approach could help unlock clues to other diseases such as ALS.

“We are one of the first labs to report the formation of spinal organoids. Our study presents a new method for culturing human spinal-cord-like tissues that could be crucial for future research.”

Just yesterday the CIRM Board awarded almost $4 million to Ankasa Regenerative Therapeutics to try and develop a treatment for another debilitating back problem called degenerative spondylolisthesis.

And finally, organoid modeling was used to better understand and study an infectious disease. Scientists from the Max Planck Institute for Infection Biology in Berlin created fallopian tube organoids from normal human cells. Fallopian tubes are the pair of tubes found inside women along which the eggs travel from the ovaries to the uterus. The scientists observed the effects of chronic infections of Chlamydia, a sexually transmittable infection. It was discovered that chronic infections lead to permanent changes at the DNA level as the cells age. These changes to DNA are permanent even after the infection is cleared, and could be indicative of the increased risk of cervical cancer observed in women with Chlamydia or those that have contracted it in the past.

Stem Cell Agency Awards Almost $4 Million to Develop a Treatment for Spinal Degeneration

Today the governing Board of the California Institute for Regenerative Medicine (CIRM) awarded $3.9 million to Ankasa Regenerative Therapeutics for a promising approach to treat a degenerative condition that can cause chronic, progressive back pain.

As we get older, the bones, joints and ligaments in our back become weak and less able to hold the spinal column in alignment.  As a result, an individual vertebral bone in our spine may slip forward over the one below it, compressing the nerves in the spine, and causing lower back pain or radiating pain.  This condition, called degenerative spondylolisthesis, primarily affects individuals over the age of 50 and, if left untreated, can cause intense pain and further degeneration of adjacent regions of the spine.

Current treatment usually involves taking bone from one of the patient’s other bones, and moving it to the site of the injury.  The transplanted bone contains stem cells necessary to generate new bone.  However, there is a caveat to this approach— as we get older the grafts become less effective because the stem cells in our bones are less efficient at making new bone.  The end result is little or no bone healing. 

Ankasa has developed ART352-L, a protein-based drug product meant to enhance the bone healing properties of these bone grafts.  ART352-L works by stimulating bone stem cells to  increase the amount of bone produced by the graft.

The award is in the form of a CLIN1 grant, with the goal of completing the testing needed to apply to the Food and Drug Administration (FDA) for permission to start a clinical trial in people.

This is a project that CIRM has supported through earlier phases of research.

“We are excited to see the development that this approach has made since its early stages and reflects our commitment to supporting the most promising science and helping it advance to the clinic,” says Maria T. Millan, MD, President & CEO of CIRM. “There is an unmet medical need in older patients with bone disorders such as degenerative spondylolisthesis.  As our population ages, it is important for us to invest in potential treatments such as these that can help alleviate a debilitating condition that predisposes to additional and fatal medical complications.”

See the animated video below for a descriptive and visual synopsis of degenerative spondylolisthesis.

Rats, research and the road to new therapies

Don Reed

Don Reed has been a champion of CIRM even before there was a CIRM. He’s a pioneer in pushing for funding for stem cell research and now he’s working hard to raise awareness about the difference that funding is making.

In a recent article on Daily Kos, Don highlighted one of the less celebrated partners in this research, the humble rat.

A BETTER RAT? Benefit #62 of the California Stem Cell Agency

By Don C. Reed

When I told my wife Gloria I was writing an article about rats, she had several comments, including: “Oo, ugh!” and also “That’s disgusting!”

Obviously, there are problems with rats, such as when they chew through electrical wires, which may cause a short circuit and burn down the house. Also, they are blamed for carrying diseased fleas in their ears and spreading the Black Plague, which in 1340 killed half of China and one-third of Europe—but this is not certain. The plague may in fact have been transmitted by human-carried parasites.

But there are positive aspects to rats as well. For instance: “…a rat paired with  another that has a disability…will be very kind to the other rat. Usually, help is offered with food, cleaning, and general care.”—GUIDE TO THE RAT, by Ginger Cardinal.

Above all, anyone who has ever been sick owes a debt to rats, specifically the Norway rat with that spectacular name, rattus norvegicus domesticus, found in labs around the world.

I first realized its importance on March 1, 2002, when I held in my hand a rat which had been paralyzed, but then recovered the use of its limbs.

The rat’s name was Fighter, and she had been given a derivative of embryonic stem cells, which restored function to her limbs. (This was the famous stem cell therapy begun by Hans Keirstead with a Roman Reed grant, developed by Geron, and later by CIRM and Asterias, which later benefited humans.)

As I felt the tiny muscles struggling to be free, it was like touching tomorrow— while my paralyzed son, Roman Reed, sat in his wheelchair just a few feet away.

Was it different working with rats instead of mice? I had heard that the far smaller lab mice were more “bitey” than rats.  

Wanting to know more about the possibilities of a “better rat”, I went to the CIRM website, (www.cirm.ca.gov) hunted up the “Tools and Technology III” section, and the following complicated sentence::

“Embryonic stem cell- based generation of rat models for assessing human cellular therapies.”

Hmm. With science writing, it always takes me a couple of readings to know what they were talking about. But I recognized some of the words, so that was a start.

“Stemcells… rat models… human therapies….”  

I called up Dr. Qilong Ying, Principle Investigator (PI) of the study.

As he began to talk, I felt a “click” of recognition, as if, like pieces of a puzzle, facts were fitting together.

It reminded me of Jacques Cousteau, the great underwater explorer, when he tried to invent a way to breathe underwater. He had the compressed air tank, and a mouthpiece that would release air—but it came in a rush, not normal breathing.

So he visited his friend, race car mechanic Emil Gagnan, and told him, “I need something that will give me air, but only when I inhale,”– and Gagnan said: “Like that?” and pointed to a metal contraption on a nearby table.

It was something invented for cars. But by adding it to what Cousteau already had, the Cousteau-Gagnan SCUBA (Self Contained Underwater Breathing Apparatus) gear was born—and the ocean could now be explored.

Qi-Long Ying’s contribution to science may also be a piece of the puzzle of cure…

A long-term collaboration with Dr. Austin Smith centered on an attempt to do with rats what had done with mice.

In 2007, the  Nobel Prize in Medicine had been won by Dr. Martin Evans, Mario Capecchi, and Oliver Smithies. Working independently, they developed “knock-out” and “knock-in” mice, meaning to take out a gene, or put one in.  

But could they do the same with rats?

 “We and others worked very, very hard, and got nowhere,” said Dr. Evans.

Why was this important?

Many human diseases cannot be mimicked in the mouse—but might be in the rat. This is for several reasons: the rat is about ten times larger; its internal workings are closer to those of a human; and the rat is considered several million years closer (in evolutionary terms) to humans than the mouse.

In 2008 (“in China, that is the year of the rat,” noted Dr. Ying in our conversation) he received the first of three grants from CIRM.

“We proposed to use the classical embryonic stem cell-based gene-targeting technology to generate rat models mimicking human heart failure, diabetes and neurodegenerative diseases…”

How did he do?

In 2010, Science Magazine honored him with inclusion in their “Top 10 Breakthroughs for using embryonic stem cell-based gene targeting to produce the world’s first knockout rats, modified to lack one or more genes…”

And in 2016, he and Dr. Smith received the McEwen Award for Innovation,  the highest honor bestowed by the International Society for Stem Cell Research (ISSCR).

Using knowledge learned from the new (and more relevant to humans) lab rat, it may be possible to develop methods for the expansion of stem cells directly inside the patient’s own bone marrow. Stem cells derived in this fashion would be far less likely to be rejected by the patient.  To paraphrase Abraham Lincoln, they would be “of the patient, by the patient and for the patient—and shall not perish from the patient”—sorry!

Several of the rats generated in Ying’s lab (to mimic human diseases) were so successful that they have been donated to the Rat Research Resource center so that other scientists can use them for their study.

“Maybe in the future we will develop a cure for some diseases because of knowledge from using rat models,” said Ying. “I think it’s very possible. So we want more researchers from USC and beyond to come and use this technology.”

And it all began with the humble rat…

Newly developed biosensor can target leukemic stem cells

Dr. Michael Milyavsky (left) and his research student Muhammad Yassin (right). Image courtesy of Tel Aviv University.

Every three minutes, one person in the United States is diagnosed with a blood cancer, which amounts to over 175,000 people every year. Every nine minutes, one person in the United States dies from a blood cancer, which is over 58,000 people every year. These eye opening statistics from the Leukemia & Lymphoma Society demonstrate why almost one in ten cancer deaths in 2018 were blood cancer related.

For those unfamiliar with the term, a blood cancer is any type of cancer that begins in blood forming tissue, such as those found in the bone marrow. One example of a blood cancer is leukemia, which results in the production of abnormal blood cells. Chemotherapy and radiation are used to wipe out these cells, but the blood cancer can sometimes return, something known as a relapse.

What enables the return of a blood cancer such as leukemia ? The answer lies in the properties of cancer stem cells, which have the ability to multiply and proliferate and can resist the effects of certain types of chemotherapy and radiation. Researchers at Tel Aviv University are looking to decrease the rate of relapse in blood cancer by targeting a specific type of cancer stem cell known as a leukemic stem cell, which are often found to be the most malignant.

Dr. Michael Milyavsky and his team at Tel Aviv University have developed a biosensor that is able to isolate, label, and target specific genes found in luekemic stem cells. Their findings were published on January 31, 2019 in Leukemia.

In a press release Dr. Milyavsky said:

“The major reason for the dismal survival rate in blood cancers is the inherent resistance of leukemic stem cells to therapy, but only a minor fraction of leukemic cells have high regenerative potential, and it is this regeneration that results in disease relapse. A lack of tools to specifically isolate leukemic stem cells has precluded the comprehensive study and specific targeting of these stem cells until now.”

In addition to isolating and labeling leukemic stem cells, Dr. Milyavsky and his team were able to demonstrate that the leukemic stem cells labeled by their biosensor were sensitive to an inexpensive cancer drug, highlighting the potential this technology has in creating more patient-specific treatment options.

In the article, Dr. Milyavsky said:

” Using this sensor, we can perform personalized medicine oriented to drug screens by barcoding a patient’s own leukemia cells to find the best combination of drugs that will be able to target both leukemia in bulk as well as leukemia stem cells inside it.”

The researchers are now investigating genes that are active in leukemic stem cells in the hope finding other druggable targets.

CIRM has funded two clinical trials that also use a more targeted approach for cancer treatment. One of these trials uses an antibody to treat chronic lymphocytic leukemia (CLL) and the other trial uses a different antibody to treat acute myeloid leukemia (AML).

Facebook Live – Ask the Stem Cell Team about Patient Advocacy

How often do you get to ask an expert a question about something that matters deeply to you and get an answer right away? Not very often I’m guessing. That’s why CIRM’s Facebook Live “Ask the Stem Cell Team About Patient Advocacy” gives you a chance to do just that this Thursday, March 14th from noon till 1pm PST.

We have three amazing individuals who will share their experiences, their expertise and advice as Patient Advocates, and answer your questions about how to be an effective advocate for your cause.

The three are:

Gigi McMillan became a Patient Advocate when her 5-year-old son was diagnosed with a brain tumor. That led her to helping develop support systems for families going through the same ordeal, to help researchers develop appropriate consent processes and to campaign for the rights of children and their families in research.

Adrienne Shapiro comes from a family with a long history of Sickle Cell Disease (SCD) and has fought to help people with SCD have access to compassionate care. She is the co-founder of Axis Advocacy, an organization dedicated to raising awareness about SCD and support for those with it. In addition she is now on the FDA’s Patient Engagement Collaborative, a new group helping the FDA ensure the voice of the patient is heard at the highest levels.

David Higgins is a CIRM Board member and a Patient Advocate for Parkinson’s Disease. David has a family history of the disease and in 2011 was diagnosed with Parkinson’s. As a scientist and advocate he has championed research into the disease and worked to raise greater awareness about the needs of people with Parkinson’s.

Also, make sure to “like” our FaceBook page before the event to receive a notification when we’ve gone live for this and future events. If you miss the broadcast, not to worry. We’ll be posting it on our Facebook video page, our website, and YouTube channel shortly afterwards.

We want to answer your most pressing questions, so please email them directly to us beforehand at info@cirm.ca.gov.

And, of course, feel free to share this information with anyone you think might be interested.

Of Mice and Men, and Women Too; Stem cell stories you might have missed

Mice brains can teach us a lot

Last week’s news headlines were dominated by one big story, the use of a stem cell transplant to effectively cure a person of HIV. But there were other stories that, while not quite as striking, did also highlight how the field is advancing.

A new way to boost brain cells (in mice!)

It’s hard to fix something if you don’t really know what’s wrong in the first place. It would be like trying to determine why a car is not working just by looking at the hood and not looking inside at the engine. The human brain is far more complex than a car so trying to determine what’s going wrong is infinitely more challenging. But a new study could help give us a new option.

Researchers in Luxembourg and Germany have developed a new computer model for what’s happening inside the brain, identifying what cells are not operating properly, and fixing them.

Antonio del Sol, one of the lead authors of the study – published in the journal Cell – says their new model allows them to identify which stem cells are active and ready to divide, or dormant. 

“Our results constitute an important step towards the implementation of stem cell-based therapies, for instance for neurodegenerative diseases. We were able to show that, with computational models, it is possible to identify the essential features that are characteristic of a specific state of stem cells.”

The work, done in mice, identified a protein that helped keep brain stem cells inactive in older animals. By blocking this protein they were able to help “wake up” those stem cells so they could divide and proliferate and help regenerate the aging brain.

And if it works in mice it must work in people right? Well, that’s what they hope to see next.

Deeper understanding of fetal development

According to the Mayo Clinic between 10 and 20 percent of known pregnancies end in miscarriage (though they admit the real number may be even higher) and our lack of understanding of fetal development makes it hard to understand why. A new study reveals a previously unknown step in this development that could help provide some answers and, hopefully, lead to ways to prevent miscarriages.

Researchers at the Karolinska Institute in Sweden used genetic sequencing to follow the development stages of mice embryos. By sorting those different sequences into a kind of blueprint for what’s happening at every stage of development they were able to identify a previously unknown phase. It’s the time between when the embryo attaches to the uterus and when it begins to turn these embryonic stem cells into identifiable parts of the body.

Qiaolin Deng, Karolinska Institute

Lead researcher Qiaolin Deng says this finding provides vital new evidence.

“Being able to follow the differentiation process of every cell is the Holy Grail of developmental biology. Knowledge of the events and factors that govern the development of the early embryo is indispensable for understanding miscarriages and congenital disease. Around three in every 100 babies are born with fetal malformation caused by faulty cellular differentiation.”

The study is published in the journal Cell Reports.

Could a new drug discovery reduce damage from a heart attack?

Every 40 seconds someone in the US has a heart attack. For many it is fatal but even for those who survive it can lead to long-term damage to the heart that ultimately leads to heart failure. Now British researchers think they may have found a way to reduce that likelihood.

Using stem cells to create human heart muscle tissue in the lab, they identified a protein that is activated after a heart attack or when exposed to stress chemicals. They then identified a drug that can block that protein and, when tested in mice that had experienced a heart attack, they found it could reduce damage to the heart muscle by around 60 percent.

Prof Michael Schneider, the lead researcher on the study, published in Cell Stem Cell, said this could be a game changer.

“There are no existing therapies that directly address the problem of muscle cell death and this would be a revolution in the treatment of heart attacks. One reason why many heart drugs have failed in clinical trials may be that they have not been tested in human cells before the clinic. Using both human cells and animals allows us to be more confident about the molecules we take forward.”

Rare Disease Day – fighting for awareness and hope

It’s hard thinking of something as rare when one in 20 people are at risk of experiencing it in their lifetime. But that’s the situation with rare diseases. There are more than 7,000 of them and each affects under 200,000 people. In some cases they may only affect a few hundred people. But for each person that disease, though rare, poses a real threat. And that’s why Rare Disease Day was created.

Rare Disease Day is held on the last day of February each year.  The goal is to raise awareness among the general public about the huge impact these diseases have on people’s lives. That impact is not just on the person with the disease but on the whole family who are often struggling just to get a diagnosis.

Every year groups around the world, from patients and patient advocacy organizations to researchers and policymakers, stage events to mark the day. This year there are more than 460 events being held in 96 countries, everywhere from Albania and Andora to Tunisia and Uruguay.

Here in the US many groups organize events at State Capitols to educate elected officials and policy makers about the particular needs of these communities and the promise that scientific research holds to combat these conditions. Others have auctions to raise funds for research or public debates to raise awareness.

Each event is unique in its own way because each represents many different diseases, many different needs, and many different stories. The goal of these events is to put a human face on each condition, to give it visibility, so that it is no longer something most people have never heard of, instead it becomes something that affects someone you may know or who reminds you of someone you know.

Here’s a video from Spain that does just that.

You can find a complete list of events being held around the world to mark Rare Disease Day.

At CIRM we feel a special link to this day. That’s because many of the diseases we fund research into are rare diseases such as severe combined immunodeficiency (SCID), and ALS or Lou Gehrig’s disease, and Sickle Cell Disease.

Evie Vaccaro, cured of SCID

These diseases affect relatively small numbers of patients so they often struggle to get funding for research. Because we do not have to worry about making a profit on any therapy we help develop we can focus our efforts on supporting those with unmet medical needs. And it’s paying off. Our support has already helped develop a therapy for SCID that has cured 40 children. We have two clinical trials underway for ALS or Lou Gehrig’s disease. We also have two clinical trials for Sickle Cell Disease and have reached a milestone agreement with the National Heart, Lung and Blood Institute (NHLBI) on a partnership to help develop a cure for this crippling and life-threatening disorder.

The hope is that events like Rare Disease Day let people know that even though they have a condition that affects very few, that they are not alone, but that they are part of a wider, global community, a community committed to working to find treatments and cures for all of them.

Antibody effective in cure for rare blood disorders

3D illustration of an antibody binding to a designated target.
Illustration created by Audra Geras.

A variety of diseases can be traced to a simple root cause: problems in the bone marrow. The bone marrow contains specialized stem cells known as hematopoietic stem cells (HSCs) that give rise to different types of blood cells. As mentioned in a previous blog about Sickle Cell Disease (SCD), one problem that can occur is the production of “sickle like” red blood cells. In blood cancers like leukemia, there is an uncontrollable production of abnormal white blood cells. Another condition, known as myelodysplastic syndromes (MDS), are a group of cancers in which immature blood cells in the bone marrow do not mature and therefore do not become healthy blood cells.

For diseases that originate in the bone marrow, one treatment involves introducing healthy HSCs from a donor or gene therapy. However, before this type of treatment can take place, all of the problematic HSCs must be eliminated from the patient’s body. This process, known as pre-treatment, involves a combination of chemotherapy and radiation, which can be extremely toxic and life threatening. There are some patients whose condition has progressed to the point where their bodies are not strong enough to withstand pre-treatment. Additionally, there are long-term side effects that chemotherapy and radiation can have on infant children that are discussed in a previous blog about pediatric brain cancer.

Could there be a targeted, non-toxic approach to eliminating unwanted HSCs that can be used in combination with stem cell therapies? Researchers at Stanford say yes and have very promising results to back up their claim.

Dr. Judith Shizuru and her team at Stanford University have developed an antibody that can eliminate problematic blood forming stem cells safely and efficiently. The antibody is able to identify a protein on HSCs and bind to it. Once it is bound, the protein is unable to function, effectively removing the problematic blood forming stem cells.

Dr. Shizuru is the senior author of a study published online on February 11th, 2019 in Blood that was conducted in mice and focused on MDS. The results were very promising, demonstrating that the antibody successfully depleted human MDS cells and aided transplantation of normal human HSCs in the MDS mouse model.

This proof of concept holds promise for MDS as well as other disease conditions. In a public release from Stanford Medicine, Dr. Shizuru is quoted as saying, “A treatment that specifically targets only blood-forming stem cells would allow us to potentially cure people with diseases as varied as sickle cell disease, thalassemia, autoimmune disorders and other blood disorders…We are very hopeful that this body of research is going to have a positive impact on patients by allowing better depletion of diseased cells and engraftment of healthy cells.”

The research mentioned was partially funded by us at CIRM. Additionally, we recently awarded a $3.7 million dollar grant to use the same antibody in a human clinical trial for the so-called “bubble baby disease”, which is also known as severe combined immunodeficiency (SCID). You can read more about that award on a previous blog post linked here.

Stories that caught our eye: National Geographic takes a deep dive into iPS cells; Japanese researchers start iPS cell clinical trial for spinal cord injury; and do high fat diets increase your risk of colorectal cancer

Can cell therapy beat the most difficult diseases?

That’s the question posed in a headline in National Geographic. The answer; maybe, but it is going to take time and money.

The article focuses on the use of iPS cells, the man-made equivalent of embryonic stem cells that can be turned into any kind of cell or tissue in the body. The reporter interviews Kemal Malik, the member of the Board of Management for pharmaceutical giant Bayer who is responsible for innovation. When it comes to iPS cells, it’s clear Malik is a true believer in their potential.

“Because every cell in our bodies can be produced from a stem cell, the applicability of cell therapy is vast. iPSC technology has the potential to tackle some of the most challenging diseases on the planet.”

But he also acknowledges that the field faces some daunting challenges, including:

  • How to manufacture the cells on a large scale without sacrificing quality and purity
  • How do you create products that have a stable shelf life and can be stored until needed?
  • How do you handle immune reactions if you are giving these cells to patients?

Nonetheless, Malik remains confident we can overcome those challenges and realize the full potential of these cells.

“I believe human beings are on the cusp of the next big wave of pharmaceutical innovation. The use of living cells to make people better.”

As if to prove Malik right there was also news this week that researchers at Japan’s Keio University have been given permission to start a clinical trial using iPS cells to treat people with spinal cord injuries. This would be the first of its kind anywhere in the world.

Japan launches iPSC clinical trial for spinal cord injury

An article in Biospace says that the researchers plan to treat four patients who have suffered varying degrees of paralysis due to a spinal cord injury.  They will take cells from the patients and, using the iPS method, turn them into the kind of nerve cells found in the spinal cord, and then transplant two million of them back into the patient. The hope is that this will create new connections that restore movement and feeling in the individuals.

This trial is expected to start sometime this summer.

CIRM has already funded a first-of-its-kind clinical trial for spinal cord injury with Asterias Biotherapeutics. That clinical trial used embryonic stem cells turned into oligodendrocyte progenitor cells – which develop into cells that support and protect nerve cells in the central nervous system. We blogged about the encouraging results from that trial here.

High fat diet drives colorectal cancer

Finally today, researchers at Salk have uncovered a possible cause to the rise in colorectal cancer deaths among people under the age of 55; eating too much high fat food.

Our digestive system works hard to break down the foods we eat and one way it does that is by using bile acids. Those acids don’t just break down the food, however, they also break down the lining of our intestines. Fortunately, our gut has a steady supply of stem cells that can repair and replace that lining. Unfortunately, at least according to the team from Salk, mutations in these stem cells can lead to colorectal cancer.

The study, published in the journal Cell, shows that bile acids affect a protein called FXR that is responsible for ensuring that gut stem cells produce a steady supply of new lining for the gut wall. When someone eats a high fat diet it upsets the balance of bile acids, starting a cascade of events that help cancer develop and grow.

In a news release Annette Atkins, a co-author of the study, says there is a strong connection between bile acid and cancer growth:

“We knew that high-fat diets and bile acids were both risk factors for cancer, but we weren’t expecting to find they were both affecting FXR in intestinal stem cells.”

So next time you are thinking about having that double bacon cheese burger for lunch, you might go for the salad instead. Your gut will thank you. And it might just save your life.

A new stem cell derived tool for studying brain diseases

Sergiu Pasca’s three-dimensional culture makes it possible to watch how three different brain-cell types – oligodendrocytes (green), neurons (magenta) and astrocytes (blue) – interact in a dish as they do in a developing human  brain.
Courtesy of the Pasca lab

Neurological diseases are among the most daunting diagnoses for a patient to receive, because they impact how the individual interacts with their surroundings. Central to our ability to provide better treatment options for these patients, is scientists’ capability to understand the biological factors that influence disease development and progression. Researchers at the Stanford University School of Medicine have made an important step in providing neuroscientists a better tool to understand the brain.

While animal models are excellent systems to study the intricacies of different diseases, the ability to translate any findings to humans is relatively limited. The next best option is to study human stem cell derived tissues in the laboratory. The problem with the currently available laboratory-derived systems for studying the brain, however, is the limited longevity and diversity of neuronal cell types. Dr. Sergiu Pasca’s team was able to overcome these hurdles, as detailed in their study, published in the journal Nature Neuroscience.

A new approach

Specifically, Dr. Pasca’s group developed a method to differentiate or transform skin derived human induced pluripotent stem cells (iPSCs – which are capable of becoming any cell type) into brain-like structures that mimic how oligodendrocytes mature during brain development. Oligodendrocytes are most well known for their role in myelinating neurons, in effect creating a protective sheath around the cell to protect its ability to communicate with other brain cells. Studying oligodendrocytes in culture systems is challenging because they arise later in brain development, and it is difficult to generate and maintain them with other cell types found in the brain.

These scientists circumvented this problem by using a unique combination of growth factors and nutrients to culture the oligodendrocytes, and found that they behaved very similarly to oligodendrocytes isolated from humans. Most excitingly, they observed that the stem cell-derived oligodendrocytes were able to myelinate other neurons in the culture system. Therefore they were both physically and functionally similar to human oligodendrocytes.

Importantly, the scientists were also able to generate astrocytes alongside the oligodendrocytes. Astrocytes perform many important functions such as providing essential nutrients and directing the electrical signals that help cells in the brain communicate with each other. In a press release, Dr. Pasca explains the importance of generating multiple cell types in this in vitro system:

“We now have multiple cell types interacting in one single culture. This permits us to look close-up at how the main cellular players in the human brain are talking to each other.”

This in vitro or laboratory-developed system has the potential to help scientists better understand oligodendrocytes in the context of diseases such as multiple sclerosis and cerebral palsy, both of which stem from improper myelination of brain nerve cells.

This work was partially supported by a CIRM grant.