Stem cells help researchers map out glaucoma in search for new treatments

Glaucoma is the world’s leading cause of irreversible blindness. There is no cure and current treatments are only able to slow down the progression of the disease. Now research using stem cells to create a genetic blueprint of glaucoma is giving scientist a powerful new tool to combat the disease.

Glaucoma occurs when healthy retinal ganglion cells, which relay information from the eyes to the brain, are damaged and die. However, researchers were unable to really understand what was happening because the only way to look at retinal ganglion cells was through very invasive procedures.

So, researchers in Australia took skin cells from people with glaucoma and people with healthy eyes and, using the iPSC method, turned them into retinal ganglion cells. They were then able to map the genetic expression of these cells and compare the healthy cells with the diseased ones.

In an interview with Science Daily, Professor Joseph Powell , who led the team, says they were able to identify more than 300 unique genetic features which could provide clues as to what is causing the vision loss.

“The sequencing identifies which genes are turned on in a cell, their level of activation and where they are turned on and off like a road network with traffic lights. This research gives us a genetic roadmap of glaucoma and identifies 312 sites in the genome where these lights are blinking. Understanding which of these traffic lights should be turned off or on will be the next step in developing new therapies to prevent glaucoma.”

Powell says by identifying underlying causes for glaucoma researchers may be able to develop new, more effective therapies.

The study is published in Cell Genomics.

Replacement brain cells offer hope for Parkinson’s treatment

A colony of iPSCs from a Parkinson’s patient (left) and dopaminergic neurons made from these iPSCs (right) to model PD. (Image credit: Jeanne Loring)

A new study that used adult blood stem cells to create replacement brain nerve cells appears to help rats with Parkinson’s.

In Parkinson’s, the disease attacks brain nerve cells that produce a chemical called dopamine. The lack of dopamine produces a variety of symptoms including physical tremors, depression, anxiety, insomnia and memory problems. There is no cure and while there are some effective treatments they tend to wear off over time.

In this study, researchers at Arizona State University took blood cells from humans and, using the iPSC method, changed those into dopamine-producing neurons. They then cultured those cells in the lab before implanting them in the brains of rats which had Parkinson’s-like symptoms.

They found that rats given cells that had been cultured in the lab for 17 days survived in greater numbers and seemed to be better at growing new connections in their brains, compared to rats given cells that had been cultured for 24 or 37 days.

In addition, those rats given larger doses of the cells experienced a complete reversal of their symptoms, compared to rats given smaller doses.

In a news release, study co-author Dr. Jeffrey Kordower, said: “We cannot be more excited by the opportunity to help individuals who suffer from [a] genetic form of Parkinson’s disease, but the lessons learned from this trial will also directly impact patients who suffer from sporadic, or non-genetic forms of this disease.”

The study, published in the journal npj Regenerative Medicine, says this approach might also help people suffering from other neurological diseases like Alzheimer’s or Huntington’s disease.

COVID is a real pain in the ear

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The more you learn about COVID-19 the more there is to dislike about it. The global death toll from the virus is now more than five million and for those who survive there can be long-term health consequences. We know COVID can attack the lungs, heart and brain. Now we are learning it can also mess up your ears causing hearing problems, ringing in the ear (tinnitus) and leave you dizzy.

Viral infections are a known cause of hearing loss and other kinds of infection. That’s why, before the pandemic started, Dr. Konstantina Stantovic at Massachusetts Eye and Ear and Dr. Lee Gherke at MIT had been studying how and why things like measles, mumps and hepatitis affected people’s hearing. After COVID hit they heard reports of patients experiencing sudden hearing loss and other problems, so they decided to take a closer look.

They took cells from ten patients who had all experienced some hearing or ear-related problems after testing positive for COVID and, using the iPSC method, turned those cells into the kind found in the inner ear including hair cells, supporting cells, nerve fibers, and Schwann cells.  

They then compared those to cells from patients who had similar hearing issues but who had not been infected with COVID. They found that the hair and Schwann cells both had proteins the virus can use to infect cells. That’s important because hair cells help with balance and the Schwann cells play a protective role for neuronal axons, which help different nerve cells in the brain communicate with each other.

In contrast, some of the other cells in the inner ear didn’t have those proteins and so were protected from COVID.

In a news release Dr. Stankovic says it’s not known how many people infected with COVID experienced hearing issues. “Initially this was because routine testing was not readily available for patients who were diagnosed with COVID, and also, when patients were having more life-threatening complications, they weren’t paying much attention to whether their hearing was reduced or whether they had tinnitus. We still don’t know what the incidence is, but our findings really call for increased attention to audio vestibular symptoms in people with Covid exposure.”

The doctors are not sure how the virus gets into the inner ear but speculate that it may enter through the Eustachian tube, that’s a small passageway that connects your throat to your middle ear. When you sneeze, swallow, or yawn, your Eustachian tubes open, preventing air pressure and fluid from building up inside your ear. They think that might allow particles from the nose to spread to the ear.

The study is published in the journal Communications Medicine.

CIRM has funded 17 different projects targeting COVID-19, several of which are still active.

A step forward in finding a treatment for a deadly neurological disorder

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MRI section of a brain affected by ALS with the front section of the brain highlighted

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a nasty disease that steadily attacks nerve cells in the brain and spinal cord. It’s pretty much always fatal within a few years. As if that wasn’t bad enough, ALS also can overlap with a condition called frontotemporal dementia (ALS/FTD). Together these conditions cause devastating symptoms of muscle weakness along with changes in memory, behavior and personality.

Now researchers at Cambridge University in the UK have managed to grow groups of cells called “mini-brains” that mimic ALS/FTD and could lead to new approaches to treating this deadly combination.

We have written about these mini-brains before. Basically, they are created, using the iPSC method, that takes skin or blood cells from a patient with a particular condition, in this case ALS/FTD, and turns them into the kind of nerve cells in the brain affected by the disease. Because they came from someone who had ALS/FTD they display many of the characteristics of the disease and this gives researchers a great tool to study the condition.

This kind of approach has been done before and given researchers a glimpse into what is happening in the brains of people with ALS/FTD. But in the past those cells were in a kind of clump, and it wasn’t possible to get enough nutrients to the cells in the middle of the clump for the mini-brain to survive for long.

What is different about the Cambridge team is that they were able to create these mini-brains using thin, slices of cells. That meant all the cells could get enough nutrients to survive a long time, giving the team a better model to understand what is happening in ALS/FTD.

In a news release, Dr András Lakatos, the senior author of the study, said: “Neurodegenerative diseases are very complex disorders that can affect many different cell types and how these cells interact at different times as the diseases progress.

“To come close to capturing this complexity, we need models that are more long-lived and replicate the composition of those human brain cell populations in which disturbances typically occur, and this is what our approach offers. Not only can we see what may happen early on in the disease – long before a patient might experience any symptoms – but we can also begin to see how the disturbances change over time in each cell.”

Thanks to these longer-lived cells the team were able to see changes in the mini-brains at a very early stage, including damage to DNA and cell stress, changes that affected other cells which play a role in muscle movements and behavior.

Because the cells developed using the iPSC method are from a patient with ALS/FTD, the researchers were able to use them to screen many different medications to see if any had potential as a therapy. They identified one, GSK2606414, that seemed to help in reducing the build-up of toxic proteins, reduced cell stress and the loss of nerve cells.

The team acknowledge that these results are promising but also preliminary and will require much more research to verify them.

CIRM has funded three clinical trials targeting ALS. You can read about that work here.

Building a better brain (model) in the lab

Leica Picture of a brain organoid: courtesy National Institute of Allergy and Infectious Diseases, NIH

One of the biggest problems with trying to understand what is happening in a disease that affects the brain is that it’s really difficult to see what is going on inside someone’s head. People tend to object to you trying to open their noggin while they are still using it.

New technologies can help, devices such as MRI’s – which chart activity and function by measuring blood flow – or brain scans using electroencephalograms (EEGs), which measure activity by tracking electrical signaling and brain waves. But these are still limited in what they can tell us.

Enter brain organoids. These are three dimensional models made from clusters of human stem cells grown in the lab. They aren’t “brains in a dish” – they can’t function or think independently – but they can help us develop a deeper understanding of how the brain works and even why it doesn’t always work as well as we’d like.

Now researchers at UCLA’s Broad Center of Regenerative Medicine have created brain organoids that demonstrate brain wave activity similar to that found in humans, and even brain waves found in particular neurological disease.

The team – with CIRM funding – took skin tissue from healthy individuals and, using the iPSC method – which enables you to turn these cells into any other kind of cell in the body – they created brain organoids. They then studied both the physical structure of the organoids by examining them under a microscope, and how they were functioning by using a probe to measure brain wave activity.

In a news release Dr. Ranmal Samarasinghe, the first author of the study in the journal Nature Neuroscience, says they wanted to do this double test for a very good reason: “With many neurological diseases, you can have terrible symptoms but the brain physically looks fine. So, to be able to seek answers to questions about these diseases, it’s very important that with organoids we can model not just the structure of the brain but the function as well.”

Next, they took skin cells from people with a condition called Rhett syndrome. This is a rare genetic disorder that affects mostly girls and strikes in the first 18 months of life, having a severe impact on the individual’s ability to speak, walk, eat or even breathe easily. When the researchers created brain organoids with these cells the structure of the organoids looked similar to the non-Rhett syndrome ones, but the brain wave activity was very different. The Rhett syndrome organoids showed very erratic, disorganized brain waves.

When the team tested an experimental medication called Pifithrin-alpha on the Rhett organoids, the brain waves became less erratic and more like the brain waves from the normal organoids.

“This is one of the first tangible examples of drug testing in action in a brain organoid,” said Samarasinghe. “We hope it serves as a stepping stone toward a better understanding of human brain biology and brain disease.”

Paving the way for a treatment for dementia

What happens in a stroke

When someone has a stroke, the blood flow to the brain is blocked. This kills some nerve cells and injures others. The damaged nerve cells are unable to communicate with other cells, which often results in people having impaired speech or movement.

While ischemic and hemorrhagic strokes affect large blood vessels and usually produce recognizable symptoms there’s another kind of stroke that is virtually silent. A ‘white’ stroke occurs in blood vessels so tiny that the impact may not be noticed. But over time that damage can accumulate and lead to a form of dementia and even speed up the progression of Alzheimer’s disease.

Now Dr. Tom Carmichael and his team at the David Geffen School of Medicine at UCLA have developed a potential treatment for this, using stem cells that may help repair the damage caused by a white stroke. This was part of a CIRM-funded study (DISC2-12169 – $250,000).

Instead of trying to directly repair the damaged neurons, the brain nerve cells affected by a stroke, they are creating support cells called astrocytes, to help stimulate the body’s own repair mechanisms.

In a news release, Dr. Irene Llorente, the study’s first author, says these astrocytes play an important role in the brain.

“These cells accomplish many tasks in repairing the brain. We wanted to replace the cells that we knew were lost, but along the way, we learned that these astrocytes also help in other ways.”

The researchers took skin tissue and, using the iPSC method (which enables researchers to turn cells into any other kind of cell in the body) turned it into astrocytes. They then boosted the ability of these astrocytes to produce chemical signals that can stimulate healing among the cells damaged by the stroke.

These astrocytes were then not only able to help repair some of the damaged neurons, enabling them to once again communicate with other neurons, but they also helped another kind of brain cell called oligodendrocyte progenitor cells or OPCs. These cells help make a protective sheath around axons, which transmit electrical signals between brain cells. The new astrocytes stimulated the OPCs into repairing the protective sheath around the axons.

Mice who had these astrocytes implanted in them showed improved memory and motor skills within four months of the treatment.  

And now the team have taken this approach one step further. They have developed a method of growing these astrocytes in large amounts, at very high quality, in a relatively short time. The importance of that is it means they can produce the number of cells needed to treat a person.

“We can produce the astrocytes in 35 days,” Llorente says. “This process allows rapid, efficient, reliable and clinically viable production of our therapeutic product.”

The next step is to chat with the Food and Drug Administration (FDA) to see what else they’ll need to do to show they are ready for a clinical trial.

The study is published in the journal Stem Cell Research.

City of Hope scientists use stem cells to develop ‘mini-brains’ to study Alzheimer’s and to test drugs in development

Alzheimer’s is a progressive disease that destroys memory and other important mental functions. According to the non-profit HFC, co-founded by CIRM Board member Lauren Miller Rogen and her husband Seth Rogen, more than 5 million Americans are living with Alzheimer’s. It is the 6th leading cause of death in the U.S and it is estimated that by 2050 as many as 16 million Americans will have the disease. Alzheimer’s is the only cause of death among the top 10 in the U.S. without a way to prevent, cure, or even slow its progression, which is it is crucial to better understand the disease and to develop and test potential treatments.

It is precisely for this reason that researchers led by Yanhong Shi, Ph.D. at City of Hope have developed a ‘mini-brain’ model using stem cells in order to study Alzheimer’s and to test drugs in development.

The team was able to model sporadic Alzheimer’s, the most common form of the disease, by using human induced pluripotent stem cells (iPSCs), a kind of stem cell that can be created from skin or blood cells of people through reprogramming and has the ability to turn into virtually any other kind of cell. The researchers used these iPSCs to create ‘mini-brains’, also known as brain organoids, which are 3D models that can be used to analyze certain features of the human brain. Although they are far from perfect replicas, they can be used to study physical structure and other characteristics. 

The scientists exposed the ‘mini-brains’ to serum that mimics age-associated blood-brain barrier (BBB) breakdown. The BBB is a protective barrier that surrounds the brain and its breakdown has been associated with Alzheimer’s and other age-related neurodegenerative diseases . After exposure, the team tested the ‘mini-brains’ for various Alzheimer’s biomarkers. These markers included elevated levels of proteins known as amyloid and tau that are associated with the disease and synaptic breaks linked to cognitive decline.

Research using brain organoids has shown that exposure to serum from blood could induce multiple Alzheimer’s symptoms. This suggests that combination therapies targeting multiple areas would be more effective than single-target therapies currently in development.

The team found that attempting a single therapy, such as inhibiting only amyloid or tau proteins, did not reduce the levels of tau or amyloid, respectively. These findings suggest that amyloid and tau likely cause disease progression independently. Furthermore, exposure to serum from blood, which mimics BBB breakdown, could cause breaks in synaptic connections that help brains remember things and function properly.

Image Description: Yanhong Shi, Ph.D.

In a press release from the Associated Press, Dr. Shi elaborated on the importance of their model for studying Alzheimer’s.

“Drug development for Alzheimer’s disease has run into challenges due to incomplete understanding of the disease’s pathological mechanisms. Preclinical research in this arena predominantly uses animal models, but there is a huge difference between humans and animals such as rodents, especially when it comes to brain architecture. We, at City of Hope, have created a miniature brain model that uses human stem cell technology to study Alzheimer’s disease and, hopefully, to help find treatments for this devastating illness.”

The full results of this study were published in Advance Science.

Dr. Shi has previously worked on several CIRM-funded research projects, such as looking at a potential link between COVID-19 and a gene for Alzheimer’s as well as the development of a therapy for Canavan disease.

UCSD researchers use stem cell model to better understand pregnancy complication

A team of UC San Diego researchers recently published novel preeclampsia models to aid in understanding this pregnancy complication that occurs in one of 25 U.S. pregnancies. Researchers include (left to right): Ojeni Touma, Mariko Horii, Robert Morey and Tony Bui. Credit: UC San Diego

Pregnant women often tread uncertain waters in regards to their health and well-being as well as that of their babies. Many conditions can arise and one of these is preeclampsia, a type of pregnancy complication that occurs in approximately one in 25 pregnancies in the United States according to the Center for Disease Control (CDC). It occurs when expecting mothers develop high blood pressure, typically after 20 weeks of pregnancy, and that in turn reduces the blood supply to the baby. This can lead to serious, even fatal, complications for both the mother and baby.

A CIRM supported study using induced pluripotent stem cells (iPSCs), a kind of stem cell that can turn into virtually any cell type, was able to create a “disease in a dish” model in order to better understand preeclampsia.

Credit: UC San Diego

For this study, Mariko Horii, M.D., and her team of researchers at the UC San Diego School of Medicine obtained cells from the placenta of babies born under preeclampsia conditions. These cells were then “reprogrammed” into a stem cell-like state, otherwise known as iPSCs. The iPSCs were then turned into cells resembling placental cells in early pregnancy. This enabled the team to create the preeclampsia “disease in the dish” model. Using this model, they were then able to study the processes that cause, result from, or are otherwise associated with preeclampsia.

The findings revealed that cellular defects observed are related to an abnormal response in the environment in the womb. Specifically, they found that preeclampsia was associated with a low-oxygen environment in the uterus. The researchers used a computer modeling system at UC San Diego known as Comet to detail the differences between normal and preeclampsia placental tissue.

Horii and her team hope that these findings not only shed more light on the environment in the womb observed in preeclampsia, but also provided insight for future development of diagnostic tools and identification of potential medications. Furthermore, they hope that their iPSC disease model can be used to study other placenta-associated pregnancy disorders such as fetal growth restriction, miscarriage, and preterm birth.

The team’s next steps are to develop a 3D model to better study the relationship between environment and development of placental disease.

In a news release from UC San Diego, Horri elaborates more on these future goals.

“Currently, model systems are in two-dimensional cultures with single-cell types, which are hard to study as the placenta consists of maternal and fetal cells with multiple cell types, such as placental cells (fetal origin), maternal immune cells and maternal endometrial cells. Combining these cell types together into a three-dimensional structure will lead to a better understanding of the more complex interactions and cell-to-cell signaling, which can then be applied to the disease setting to further understand pathophysiology.”

The full study was published in Scientific Reports.

Stem cell treatment improves motor function in monkeys modeling Parkinson’s Disease

Neurodegenerative diseases impact millions of people worldwide with the risk of being affected by one of these diseases increasing as you get older. For many of these diseases, there are very few treatments available to patients. As life expectancy increases and the population continues to age, it is crucial to try and find treatments that can potentially slow the progression of these diseases or cure them entirely. This is one of the reasons why CIRM has committed directing around $1.5 billion in funding over the next few years to research related to neurological disorders.

One of the most common neurodegenerative diseases is Parkinson’s Disease (PD), a movement disorder that affects one million people in the U.S alone and leads to shaking, stiffness, insomnia, fatigue, and problems with walking, balance, and coordination.  It is caused by the breakdown and death of dopaminergic neurons, special nerve cells in the brain responsible for the production of dopamine, a chemical messenger that is crucial for normal brain activity.

A recent study published in Nature Medicine has shown improved motor function and growth of neurons over a two year period in monkeys modeling PD. The study was conducted by Su-Chun Zhang, M.D., Ph.D. and his team at the University of Wisconsin using induced pluripotent stem cells (iPSCs), a kind of stem cell that can become virtually any type of cell that can be made from skin cells. The hope is that these results can pave the way for starting human clinical trials.

In order to replicate PD in humans, the team injected 10 adult monkeys with a neurotoxin that produces PD like symptoms. As a result of this, all 10 monkeys developed slow movements, imbalances, tremors, and impaired coordination in the hand on the opposite side of the injection. Additionally, scans revealed that on the injected side, monkeys lost most brain activity involving dopamine in two key brain areas. The team then waited three years after injecting the neurotoxin before administering the therapy, during which time the monkeys’ symptoms persisted.

To generate iPSC lines, the team obtained skin cells from five of the monkeys. The iPSCs were then turned into dopamine neural progenitor cells, which have the ability to create dopamine. These newly created cells were then administered into the brains of the five monkeys, with each monkey receiving a treatment derived from their own skin cells. A sixth iPSC line from a donor monkey was used for the remaining five monkeys to see how the treatment would work if it was not derived from their own skin cells.

The results showed that the monkeys that received the treatment derived from their own skin cells recovered. These animals moved more, moved faster, and were nimbler than before the treatment. They gained the ability to grasp treats, use all four limbs for walking, and climb their cages with ease and increased agility. However, the monkeys that received iPSCs derived from a donor did not recover. Their symptoms remained unchanged or worsened compared to before the treatment.

In a news article, Zhang emphasizes how he and his team are proceeding with a treatment derived from one’s own cells (autologous) vs. one from a donor (allogeneic).

“I initially wanted to do allogeneic transplants in patients because the autologous approach is too expensive. However, after seeing [our] data, I changed my mind. I want to go with the autologous first… because I feel the chance of success is really, really high.”

CIRM is currently funding a human clinical trial ($5.5 million) that is using a gene therapy approach for PD.

A new way to evade immune rejection in transplanting cells

Immune fluorescence of HIP cardiomyocytes in a dish; Photo courtesy of UCSF

Transplanting cells or an entire organ from one person to another can be lifesaving but it comes with a cost. To avoid the recipient’s body rejecting the cells or organ the patient has to be given powerful immunosuppressive medications. Those medications weaken the immune system and increase the risk of infections. But now a team at the University of California San Francisco (UCSF) have used a new kind of stem cell to find a way around that problem.

The cells are called HIP cells and they are a specially engineered form of induced pluripotent stem cell (iPSC). Those are cells that can be turned into any kind of cell in the body. These have been gene edited to make them a kind of “universal stem cell” meaning they are not recognized by the immune system and so won’t be rejected by the body.

The UCSF team tested these cells by transplanting them into three different kinds of mice that had a major disease; peripheral artery disease; chronic obstructive pulmonary disease; and heart failure.

The results, published in the journal Proceedings of the National Academy of Science, showed that the cells could help reduce the incidence of peripheral artery disease in the mice’s back legs, prevent the development of a specific form of lung disease, and reduce the risk of heart failure after a heart attack.

In a news release, Dr. Tobias Deuse, the first author of the study, says this has great potential for people. “We showed that immune-engineered HIP cells reliably evade immune rejection in mice with different tissue types, a situation similar to the transplantation between unrelated human individuals. This immune evasion was maintained in diseased tissue and tissue with poor blood supply without the use of any immunosuppressive drugs.”

Deuse says if this does work in people it may not only be of great medical value, it may also come with a decent price tag, which could be particularly important for diseases that affect millions worldwide.

“In order for a therapeutic to have a broad impact, it needs to be affordable. That’s why we focus so much on immune-engineering and the development of universal cells. Once the costs come down, the access for all patients in need increases.”