Stem cell stories that caught our eye: Reprogramming cells in vivo may help heal ulcers, CIRM-funded clinical trial shows promise and a New report, clears up an old question.

Stem cell image of the week:  New Research out of the Salk Institute could bring us closer to reprogramming stem cells without taking them out of the body (Adonica Shaw)

Our stem cell image of the week could be a step towards reprogramming cells in vivo.

The image represents the first proof of principle for the successful regeneration of a functional organ (the skin) inside a mammal, by a technique known as AAV-based in vivo reprogramming. Epithelial (skin) tissues were generated by converting one cell type (red: mesenchymal cells) to another (green: basal keratinocytes) within a large ulcer in a laboratory mouse model.

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Photo courtesy of the Salk Institute

In large patches of ulcerous skin, surviving cells prioritize inflammation and wound closure. That’s what they’re programmed to do. Cells, on the other hand, can be reprogrammed in living tissue, wounded tissue, to expedite healing.

A group of scientists at the Salk Institute developed a new approach to cellular reprogramming. They found a way to directly convert the cells in an open wound into new skin cells. Their findings were published on Wednesday in Nature.

Reprogramming wound-resident cells could be useful for healing skin damage, countering the effects of aging, and helping us to better understand skin cancer. It could also supplant plastic surgery and the application of skin grafts as a way to treat large cutaneous ulcers, including those seen in people with severe burns, bedsores, or chronic diseases such as diabetes.

When an ulcer is especially large, it can be difficult for surgeons to graft enough skin. In these cases, researchers can isolate skin stem cells from a patient, grow them in the lab and transplant them back into the patient. However, such a procedure requires an extensive amount of time, which may put the patient’s life at risk and is sometimes not effective.

 “Our observations constitute an initial proof of principle for in vivo regeneration of an entire three-dimensional tissue like the skin, not just individual cell types as previously shown,” says Dr. Izpisua Belmonte. “This knowledge might not only be useful for enhancing skin repair but could also serve to guide in vivo regenerative strategies in other human pathological situations, as well as during aging, in which tissue repair is impaired.”

Positive news from a CIRM-funded clinical trial targeting a deadly blood cancer. (Kevin McCormack)  Multiple myeloma is a type of blood cancer where certain cells in the bone marrow grow out of control, crowding out the healthy cells and forming tumors. There is no cure but there are many treatments that can slow down or even halt the progression. Over time, however, many of those treatments lose their effectiveness and the cancer returns. Now a new CIRM-funded clinical trial targeting this kind of relapsing multiple myeloma is showing promise.

The trial, by Poseida Therapeutics, takes an immunotherapy approach that uses the patient’s own engineered immune system T cells to seek and destroy the myeloma cells. This product, called P-BCMA-101, is a stem cell memory chimeric antigen receptor T-cell (CAR-T).

In the first eleven patients treated there were no serious side effects and only one patient had a suspected case of cytokine release syndrome. That’s where large amounts of cytokines, immune substances, are rapidly released into the body causing fever, nausea, rapid heartbeat etc. However, even in this patient the symptoms quickly passed.

In a news release, Eric Ostertag, the CEO of Poseida said that even though the goal of this Phase 1 study was just to make sure it was safe and to identify the best dose to give patients, they have already seen a very good partial response in some patients.

“We believe our advantages of a purified product, where all cells express the CAR molecule, and a product with high levels of stem cell memory T cells, producing a more gradual and prolonged immune response against tumor cells, provide a significantly better therapeutic index when compared with other CAR-T therapeutics. We are also encouraged that P-BCMA-101 is demonstrating significant efficacy even at doses that have been ineffective for other anti-BCMA CAR-T therapies and that our response rates continue to improve as the dose increases.”

The clinical trial will eventually treat 40 patients with relapsing or remitting multiple myeloma and we will bring more results as they become available.

Techniques used in ecology help rewrite basic fact about blood stem cells (Todd Dubnicoff) It’s been over half a century since the first blood stem cell transplantation was performed. And yet, some fundamental facts about these cells – which give rise to all the cell types of our blood – have remained cloudy, like the number of blood stem cells present in the human body. This week, researchers at Wellcome Sanger Institute and Wellcome – MRC Cambridge Stem Cell Institute report that they’ve cleared up this long-lasting question.

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A blood cell colony grown from a single cell isolated from a 59-year-old man. Image Credit: Mairi Shepherd, Kent Lab

And the results were surprising. Using whole genome DNA sequencing and techniques found in ecology for tracking population sizes, the team determined that a healthy adult has between 50,000 and 200,000 blood stem cells at any given time. That’s about 10 times more than what was previously thought.

Dr. David Kent, a co-senior author on the report, described the implications of this discovery in a press release:

“This new approach is hugely flexible. Not only can we measure how many stem cells exist, we can also see how related they are to each other and what types of blood cells they produce. Applying this technique to samples from patients with blood cancers, we should now be able to learn how single cells outcompete normal cells to expand their numbers and drive a cancer.”

The study was published in Nature.

 

 

 

 

Stem cell stories that caught our eye: CIRM-funded scientist wins prestigious prize and a tooth trifecta

CIRM-grantee wins prestigious research award

Do we know how to pick ‘em or what? For a number of years now we have been funding the work of Stanford’s Dr. Marius Wernig, who is doing groundbreaking work in helping advance stem cell research. Just how groundbreaking was emphasized this week when he was named as the winner of the 2018 Ogawa-Yamanaka Stem Cell Prize.

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Marius Wernig, MD, PhD. [Photo: Stanford University]

The prestigious award, from San Francisco’s Gladstone Institutes, honors Wernig for his innovative work in developing a faster, more direct method of turning ordinary cells into, for example, brain cells, and for his work advancing the development of disease models for diseases of the brain and skin disorders.

Dr. Deepak Srivastava, the President of Gladstone, announced the award in a news release:

“Dr. Wernig is a leader in his field with extraordinary accomplishments in stem cell reprogramming. His team was the first to develop neuronal cells reprogrammed directly from skin cells. He is now investigating therapeutic gene targeting and cell transplantation–based strategies for diseases with mutations in a single gene.”

Wernig was understandably delighted at the news:

“It is a great honor to receive this esteemed prize. My lab’s goal is to discover novel biology using reprogrammed cells that aids in the development of effective treatments.”

Wernig will be presented with the award, and a check for $150,000, at a ceremony on Oct. 15 at the Gladstone Institutes in San Francisco.

A stem cell trifecta for teeth research

It was a tooth trifecta among stem cell scientists this week. At Tufts University School of Medicine, researchers made an important advance in the development of bioengineered teeth. The current standard for tooth replacement is a dental implant. This screw-shaped device acts as an artificial tooth root that’s inserted into the jawbone. Implants have been used for 30 years and though successful they can lead to implant failure since they lack many of the properties of natural teeth. By implanting postnatal dental cells along with a gel material into mice, the team demonstrated, in a Journal of Dental Research report, the development of natural tooth buds. As explained in Dentistry Today, these teeth “include features resembling natural tooth buds such as the dental epithelial stem cell niche, enamel knot signaling centers, transient amplifying cells, and mineralized dental tissue formation.”

Another challenge with the development of a bioengineered tooth replacement is reestablishing nerve connections within the tooth, which plays a critical role in its function and protection but doesn’t occur spontaneously after an injury. A research team across the “Pond” at the French National Institute of Health and Medical Research, showed that bone marrow-derived mesenchymal stem cells in the presence of a nerve fiber can help the nerve cells make connections with bioengineered teeth. The study was also published in the Journal of Dental Research.

And finally, a research report about stem cells and the dreaded root canal. When the living soft tissue, or dental pulp, of a tooth becomes infected, the primary course of action is the removal of that tissue via a root canal. The big downside to this procedure is that it leaves the patient with a dead tooth which can be susceptible to future infections. To combat this side effect, researchers at the New Jersey Institute of Technology report the development of a potential remedy: a gel containing a fragment of a protein that stimulates the growth of new blood vessels as well as a fragment of a protein that spurs dental stem cells to divide and grow. Though this technology is still at an early stage, it promises to help keep teeth alive and healthy after root canal. The study was presented this week at the National Meeting of the American Chemical Society.

Here’s an animated video that helps explain the research:

Stem cell stories that caught our eye: 3 blind mice no more and a tale of two tails

Stem cell image of the week: The demise of Three Blind Mice nursery rhyme (Todd Dubnicoff)
Our stem cell image of the week may mark the beginning of the end of the Three Blind Mice nursery rhyme and, more importantly, usher in a new treatment strategy for people suffering from vision loss. That’s because researchers from Icahn School of Medicine at Mount Sinai, New York report in Nature the ability to reprogram support cells in the eyes of blind mice to become photoreceptors, the light-sensing cells that enable sight. The image is an artistic rendering of the study results by team led Dr. Bo Chen, PhD.

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An artist’s rendering incorporates the images of the Müller glia-derived rod photoreceptors. Image credit: Bo Chen, Ph.D.

The initial inspiration for this project came from an observation in zebrafish. These creatures have the remarkable ability to restore vision after severe eye injuries. It turns out that, in response to injury, a type of cell in the eye called Muller glia – which helps maintain the structure and function of the zebrafish retina – transforms into rod photoreceptors, which allow vision in low light.

Now, Muller glia are found in humans and mice too, so the research team sought to harness this shape-shifting, sight-restoring ability of the Muller glia but in the absence of injury. They first injected a gene into the eyes of mice born blind that stimulated the glia cells to divide and grow. Then, to mimic the reprogramming process seen in zebrafish, specific factors were injected to cause the glia to change identity into photoreceptors.

The researchers showed that the glia-derived photoreceptors functioned just like those observed in normal mice and made the right connections with nerve cells responsible for sending visual information to the brain. The team’s next steps are to not only show the cells are functioning properly in the eye and brain but to also do behavioral studies to confirm that the mice can do tasks that require vision.

If these studies pan out, it could lead to a new therapeutic strategy for blinding diseases like retinitis pigmentosa and macular degeneration. Rather than transplanting replacement cells, this treatment approach would spur our own eyes to repair themselves. In the meantime, CIRM-funded researchers have studies currently in clinical trials testing stem cell-based treatments for retinitis pigmentosa and macular degeneration.

A tale of two tails: one regenerates, the other, not quite so much (Kevin McCormack) One of the wonders of nature, well two if you want to be specific, is how both salamanders and lizards are able to regrow their tails if they lose them. But there is a difference. While salamanders can regrow a tail that is almost identical to the original, lizard’s replacements are rather less impressive. Now researchers have found out why.

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In these fluorescence microscopy images, cross sections of original lizard and salamander tails (left) show cartilage (green) and nerve cells (red). In the regenerated tails (right), the lizard’s is made up mostly of cartilage, while the salamander also has developed new nerve cells. Image: Thomas Lozito

The study, published in the Proceedings of the National Academy of Sciences, shows how a lizard’s new tail doesn’t have bone but instead has cartilage, and also lacks nerve cells. The key apparently is the stem cells both use to regenerate the tail. Salamanders use neural stem cells from their spinal cord and turn them into other types of nervous system cell, such as neurons. Lizards neural stem cells are not able to do this.

The researchers, from the University of Pittsburgh, tested their findings by placing neural stem cells from the axolotl salamander into tail stumps from geckos. They noted that, as those tails regrew, some of those transplanted cells turned into neurons.

In an interview in Science News, study co-author Thomas Lozito says the team hope to take those findings and, using the CRISPR/Cas9 gene-editing tool, see if they can regenerate body parts in other animals:

 “My goal is to make the first mouse that can regenerate its tail. We’re kind of using lizards as a stepping-stone.”

Stem Cell Roundup: Knowing the nose, stem cell stress and cell fate math.

The Stem Cellar’s Image of the Week.
Our favorite image this week, comes to us from researchers at Washington University School of Medicine in St. Louis. Looking like a psychedelic Rorschach test, the fluorescence microscopy depicts mouse olfactory epithelium (in green), a sheet of tissue that develops in the nose. The team identified a new stem cell type that controls the growth of this tissue. New insights from the study of these cells could help the team better understand why some animals, like dogs, have a far superior sense of smell than humans.

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Peering into the nasal cavity of a mouse. Olfactory epithelium is indicated by green. Image credit: Lu Yang, Washington University School of Medicine in St. Louis.

A Washington U. press release provides more details about this fascinating study which appears in Developmental Cell.

How stress affects blood-forming stem cells.
Stress affects all of us in different ways. Some people handle it well. Some crack up and become nervous wrecks. So, perhaps it shouldn’t come as a huge surprise that stress also affects some stem cells. What is a pleasant surprise is that knowing this could help people undergoing cancer therapy or bone marrow transplants.

First a bit of background. Hematopoietic, or blood-forming stem cells (HSCs) come from bone marrow and are supported by other cells that secrete growth factors, including one called pleiotrophin or PTN. While researchers knew PTN was present in bone marrow they weren’t sure precisely what role it played.

So, researchers at UCLA set out to discover what PTN did.

In a CIRM-funded study they took mice that lacked PTN in endothelial cells – these line the blood vessels – or in their stromal cells – which make up the connective tissue. They found that a lack of PTN in stromal cells caused a lack of blood stem cells, but a lack of PTN in endothelial cells had no impact.

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Expression of pleiotrophin (green) in bone marrow blood vessels (red) and stromal cells (white) is shown in normal mice (left) and in mice at 24 hours following irradiation (right). Image credit: UCLA

However, as Dr. John Chute explained in a news release, when they stressed the cells, by exposing them to radiation, they found something very different:

“The surprising finding was that pleiotrophin from stromal cells was not necessary for blood stem cell regeneration following irradiation — but pleiotrophin from endothelial cells was necessary.”

In other words, during normal times the stem cells rely on PTN from stromal cells, but after stress they depend on PTN from endothelial cells.

Dr. Chute says, because treatments like chemotherapy and radiation deplete bone marrow stem cells, this finding could have real-world implications for patients.

“These therapies for cancer patients suppress our blood cell systems over time. It may be possible to administer modified, recombinant versions of pleiotrophin to patients to accelerate blood cell regeneration. This strategy also may apply to patients undergoing bone marrow transplants.”

The study appears in the journal Cell Stem Cell.

Predicting the fate of cells with math
Researchers at Harvard Medical School and the Karolinska Institutet in Sweden reported this week that they have devised a mathematical model that can predict the fate of stem cells in the brain.

It may sound like science-fiction but the accomplished the feat by tracking changes in messenger RNA (mRNA), the genetic molecule that translates our DNA code into instructions for building proteins. As a brain stem cell begins specializing into specific cell types, hundreds of genes get turns on and off, which is observed by the rate of changes in mRNA productions.

The team built their predictive model by measuring these changes. In a press release, co-senior author, Harvard professor Peter Kharchenko, described this process using a great analogy:

“Estimating RNA velocity—or the rate of RNA change over time—is akin to observing the cooks in a restaurant kitchen as they line up the ingredients to figure out what dishes they’ll be serving up next.”

The team verified their mathematical model by inputting other data that was not use in constructing the model. Karolinkska Institutet professor, Sten Linnarsson, the other co-senior author on the study, described how such a model could be applied to human biomedical research:

“RNA velocity shows in detail how neurons and other cells acquire their specific functions as the brain develops and matures. We’re especially excited that this new method promises to help reveal how brains normally develop, but also to provide clues as to what goes wrong in human disorders of brain development, such as schizophrenia and autism.”

The study appears in the journal Nature.

Stem Cell Roundup: Artificial Embryos to Study Miscarriage and ALS Insight – Muscle Repair Cells Go Rogue

Stem Cell Image of the Week: Artificial embryos for studying miscarriage (Adonica Shaw)

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Mouse embryos artificially generated by combining three types of stem cells.
Image: University of Cambridge.

This week’s stem cell image of the week comes from a team of researchers from The University of Cambridge who published research in Nature Cell Biology earlier this week indicating they’d achieved a breakthrough in stem cell research that resulted in the generation of a key developmental step that’d never before been achieved when trying to generate an artificial embryo.

To create the artificial embryo, the scientists combined mouse embryonic stem cells with two other types of stem cells that are present in the very earliest stages of embryo development. The reseachers grew the three stem cell types into a dish and coaxed them into simulating a process called gastrulation – one of the very first events that happens during a creature’s development in which the early embryo begins reorganizing into more and more complex multilayer organ structures.

In an interview with The Next Web (TNW), Professor Magdalena Zernicka-Goetz, who led the research team, says:

”Our artificial embryos underwent the most important event in life in the culture dish. They are now extremely close to real embryos. To develop further, they would have to implant into the body of the mother or an artificial placenta.”

The goal of this research isn’t to create mice on demand. Its purpose is to gain insights into early life development. And that could lead to a giant leap in our understanding of what happens during the period in a woman’s pregnancy where the risk of miscarriage is highest.

According to professor Zernicka-Goetz,

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Magdalena Zernicka-Goetz, PhD

“We can also now try to apply this to the equivalent human stem cell types and so study the very earliest events in human embryo development without actually having to use natural human embryos.The early stages of embryo development are when a large proportion of pregnancies are lost and yet it is a stage that we know very little about. Now we have a way of simulating embryonic development in the culture dish, so it should be possible to understand exactly what is going on during this remarkable period in an embryo’s life, and why sometimes this process fails.”

Muscle repair cells go rogue – a possible drug target for ALS?
Call it a case of a good cell gone bad. This week researchers at Sanford Burnham Prebys Medical Discovery Institute, report in Nature Cell Biology that fibro-adipogenic progenitors (FAPs) – cells that are critical in coordinating the repair of torn muscles – can turn rogue, causing muscles to wither and scar. This “Dr. Jekyl and Mr. Hype” discovery may lead to novel treatments for a number of incurable disorders like amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA) and spinal cord injury.

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Senior author Pier Lorenzo Puri, M.D. (right) and co-first author Luca Madaro, Ph.D. Credit: Fondazione Santa Lucia IRCCS

When muscle is strained, whether due to an acute injury or even weight-lighting, a consistent order of events occurs within the muscle. FAB cells enter the muscle tissue after immune cells called macrophages come in and gobble up dead tissue but before muscle stem cells are stimulated to regenerate the lost muscle. However, to the researchers’ surprise, something entirely different happens in the case of neuromuscular disorders like ALS where nerve signal connections to the muscles degenerate.

Once nerves are no longer attached to muscle and stop sending movement signals from the brain, the macrophages don’t infiltrate the muscle and instead the FAPs pile up in the muscle and never leave. And as a result, muscle stem cells are never activated. In ALS patients, this cellular train crash leads to progressive loss of muscle control to move the limbs and ultimately even to breathe.

The promising news from these findings, which were funded in part by CIRM, is that the team identified of an out-of-whack cell signaling pathway that is responsible for the breakdown in the rogue function of the FAP cells. The researchers hope further studies of this pathway’s role in muscle degeneration may lead to novel therapies and disease-screening technologies for ALS and other motor neuron diseases.

Stem cell roundup: summer scientists, fat-blocking cells & recent human evolution

Stem cell photo of the week: high schooler becoming a stem cell pro this summer

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High school student Anna Guzman learning important lab skills at UC Davis

This summer’s CIRM SPARK Programs, stem cell research internships for high school students, are in full swing. Along with research assignments in top-notch stem cell labs, we’ve asked the students to chronicle their internship experiences through Instagram. And today’s stem cell photo of the week is one of those student-submitted posts. The smiling intern in this photo set is Anna Guzman, a rising junior from Sheldon High School who is in the UC Davis SPARK Program. In her post, she describes the lab procedure she is doing:

“The last step in our process to harvest stem cells from a sample of umbilical cord blood! We used a magnet to isolate the CD34 marked stem cells [blood stem cells] from the rest of the solution.”

Only a few days in and Anna already looks like a pro! It’s important lab skills like this one that could land Anna a future job in the stem cell field. Check out #cirmsparklab on Instagram to view the ever-growing number of posts.

Swiss team identifies a cell type that block formation of fat cells

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(Left) Mature human fat cells grown in a Petri dish (green, lipid droplets). (Right) A section of mouse fat tissue showing, in the middle, a blood vessel (red circle) surrounded by fat cell blocking cells called Aregs (arrows). [Bart Deplancke/EPFL]

Liposuction surgery helps slim and reshape areas of a person’s body through the removal of excess fat tissue. While the patient is certainly happy to get rid of those extra pounds, that waste product is sought after by researchers because it’s a rich source of regenerative cells including fat stem cells.

The exact populations of cells in this liposuction tissue has been unclear, so a collaboration of Swiss researchers – at Ecole Polytechnique Fédérale de Lausanne (EPFL) and Eidgenössische Technische Hochschule Zürich (ETHZ) – used a cutting-edge technique allowing them to examine the gene activity within single cells.

The analysis was successful in identifying several newly defined subpopulations of cells in the fat tissue. To their surprise, one of those cell types did not specialize into fat cells but instead did the opposite: they inhibited other fat stem cells from giving rise to fat cells. The initial experiments were carried out in mice, but the team went on to show similar fat-blocking cells in human tissue. Further experiments will explore the tantalizing prospect of applying these cells to control obesity and the many diseases, like diabetes, that result from it.

The study was published June 20st in Nature.

Connection identified between recent human evolution & risk for premature birth
Evidence of recent evolution in a human gene that’s critical for maintaining pregnancy may help explain why some populations have a higher risk for giving birth prematurely than others. That’s according to a recent report by researchers at the University of Stanford School of Medicine.

The study, funded in part by CIRM’s Genomics Initiative, compared DNA from people with East Asian, European and African ancestry. They specifically examined the gene encoding the progesterone hormone receptor which helps keep a pregnant woman from going into labor too soon. The gene is also associated with preterm births, the leading cause of infant death in the U.S.

The team was very surprise to find that people with East Asian ancestry had an evolutionarily new version of the gene while the European and African populations had mixtures of new and ancient versions. These differences may explain why the risk for premature birth among East Asian populations is lower than among pregnant women of European and African descent, though environment clearly plays a role as well.

Pediatrics professor Gary Shaw, PhD, one of the team leaders, put the results in perspective:

“Preterm birth has probably been with us since the origin of the human species,” said Shaw in a press release, “and being able to track its evolutionary history in a way that sheds new light on current discoveries about prematurity is really exciting.”

The study was published June 21st in The American Journal of Human Genetics.

Friday Stem Cell Roundup: Making Nerves from Blood; New Clues to Treating Parkinson’s

Stanford lab develops method to make nerve cells from blood.

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Induced neuronal (iN) cells derived from adult human blood cells. Credit: Marius Wernig, Stanford University.

Back in 2010, Stanford Professor Marius Wernig and his team devised a method to directly convert skin cells into neurons, a nerve cell. This so-called transdifferentiation technique leapfrogs over the need to first reprogram the skin cells into induced pluripotent stem cells. This breakthrough provided a more efficient path to studying how genetics plays a role in various mental disorders, like autism or schizophrenia, using patient-derived cells. But these types of genetic analyses require data from many patients and obtaining patient skin samples hampered progress because it’s not only an invasive, somewhat painful procedure but it also takes time and money to prepare the tissue sample for the transdifferentiation method.

This week, the Wernig lab reported on a solution to this bottleneck in the journal, PNAS. The study, funded in part by CIRM, describes a variation on their transdifferentiation method which converts T cells from the immune system, instead of skin cells, into neurons. The huge advantage with T cells is that they can be isolated from readily available blood samples, both fresh or frozen. In a press release, Wernig explains this unexpected but very welcomed result:

“It’s kind of shocking how simple it is to convert T cells into functional neurons in just a few days. T cells are very specialized immune cells with a simple round shape, so the rapid transformation is somewhat mind-boggling. We now have a way to directly study the neuronal function of, in principle, hundreds of people with schizophrenia and autism. For decades we’ve had very few clues about the origins of these disorders or how to treat them. Now we can start to answer so many questions.”

Two studies targeting Parkinson’s offer new clues to treating the disease (Kevin McCormack)
Despite decades of study, Parkinson’s disease remains something of a mystery. We know many of the symptoms – trembling hands and legs, stiff muscles – are triggered by the loss of dopamine producing cells in the brain, but we are not sure what causes those cells to die. Despite that lack of certainty researchers in Germany may have found a way to treat the disease.

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Simple diagram of a mitochondria.

They took skin cells from people with Parkinson’s and turned them into the kinds of nerve cell destroyed by the disease. They found the cells had defective mitochondria, which help produce energy for the cells. Then they added a form of vitamin B3, called nicotinamide, which helped create new, healthy mitochondria.

In an article in Science & Technology Research News Dr. Michela Deleidi, the lead researcher on the team, said this could offer new pathways to treat Parkinson’s:

“This substance stimulates the faulty energy metabolism in the affected nerve cells and protects them from dying off. Our results suggest that the loss of mitochondria does indeed play a significant role in the genesis of Parkinson’s disease. Administering nicotinamide riboside may be a new starting-point for treatment.”

The study is published in the journal Cell Reports.

While movement disorders are a well-recognized feature of Parkinson’s another problem people with the condition suffer is sleep disturbances. Many people with Parkinson’s have trouble falling asleep or remaining asleep resulting in insomnia and daytime sleepiness. Now researchers in Belgium may have uncovered the cause.

Working with fruit flies that had been genetically modified to have Parkinson’s symptoms, the researchers discovered problems with neuropeptidergic neurons, the type of brain cell that helps regulate sleep patterns. Those cells seemed to lack a lipid, a fat-like substance, called phosphatidylserine.

In a news release Jorge Valadas, one of the lead researchers, said replacing the missing lipid produced promising results:

“When we model Parkinson’s disease in fruit flies, we find that they have fragmented sleep patterns and difficulties in knowing when to go to sleep or when to wake up. But when we feed them phosphatidylserine–the lipid that is depleted in the neuropeptidergic neurons–we see an improvement in a matter of days.”

Next, the team wants to see if the same lipids are low in people with Parkinson’s and if they are, look into phosphatidylserine – which is already approved in supplement form – as a means to help ease sleep problems.

Friday Stem Cell Round: Ask the Expert Facebook Live, Old Brain Cells Reveal Insights and Synthetic Development

Stem Cell Photo of the Week: We’re Live on Facebook Live!

Our stem cell photo of the week is a screenshot from yesterday’s Facebook Live event: “Ask the Expert: Stem Cells and Stroke”. It was our first foray into Facebook Live and, dare I say, it was a success with over 150 comments and 4,500 views during the live broadcast.

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Screen shot of yesterday’s Facebook Live event. Panelists included (from top left going clockwise): Sonia Coontz, Kevin McCormack, Gary Steinberg, MD, PhD and Lila Collins, PhD.

Our panel included Dr. Gary Steinberg, MD, PhD, the Chair of Neurosurgery at Stanford University, who talked about promising clinical trial results testing a stem cell-based treatment for stroke. Lila Collins, PhD, a Senior Science Officer here at CIRM, provided a big picture overview of the latest progress in stem cell therapies for stroke. Sonia Coontz, a patient of Dr. Steinberg’s, also joined the live broadcast. She suffered a devastating stroke several years ago and made a remarkable recovery after getting a stem cell therapy. She had an amazing story to tell. And Kevin McCormack, CIRM’s Senior Director of Public Communications, moderated the discussion.

Did you miss the Facebook Live event? Not to worry. You can watch it on-demand on our Facebook Page.

What other disease areas would you like us to discuss? We plan to have these Ask the Expert shows on a regular basis so let us know by commenting here or emailing us at info@cirm.ca.gov!

Brain cells’ energy “factories” may be to blame for age-related disease

Salk Institute researchers published results this week that shed new light on why the brains of older individuals may be more prone to neurodegenerative diseases like Parkinson’s and Alzheimer’s. To make this discovery, the team applied a technique they devised back in 2015 which directly converts skin cells into brain cells, aka neurons. The method skips the typical intermediate step of reprogramming the skin cells into induced pluripotent stem cells (iPSCs).

They collected skin samples from people ranging in age from 0 to 89 and generated neurons from each. With these cells in hand, the researchers then examined how increased age affects the neurons’ mitochondria, the structures responsible for producing a cell’s energy needs. Previous studies have shown a connection between faulty mitochondria and age-related disease.

While the age of the skin cells had no bearing on the health of the mitochondria, it was a different story once they were converted into neurons. The mitochondria in neurons derived from older individuals clearly showed signs of deterioration and produced less energy.

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Aged mitochondria (green) in old neurons (gray) appear mostly as small punctate dots rather than a large interconnected network. Credit: Salk Institute.

The researchers think this stark difference in the impact of age on skin cells vs. neurons may occur because neurons have higher energy needs. So, the effects of old age on mitochondria only become apparent in the neurons. In a press release, Salk scientist Jerome Mertens explained the result using a great analogy:

“If you have an old car with a bad engine that sits in your garage every day, it doesn’t matter. But if you’re commuting with that car, the engine becomes a big problem.”

The team is now eager to use this method to examine mitochondrial function in neurons derived from Alzheimer’s and Parkinson’s patient skin samples and compared them with skin-derived neurons from similarly-aged, healthy individuals.

The study, funded in part by CIRM, was published in Cell Reports.

“Synthetically” Programming embryo development

One of the most intriguing, most fundamental questions in biology is how an embryo, basically a non-descript ball of cells, turns into a complex animal with eyes, a brain, a heart, etc. A deep understanding of this process will help researchers who aim to rebuild damaged or diseased organs for patients in need.

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Researchers programmed cells to self-assemble into complex structures such as this one with three differently colored layers. Credit: Wendell Lim/UCSF

A fascinating report published this week describes a system that allows researchers to program cells to self-organize into three-dimensional structures that mimic those seen during early development. The study applied a customizable, synthetic signaling molecule called synNotch developed in the Wendell Lim’s UCSF lab by co-author Kole Roybal, PhD, now an assistant professor of microbiology and immunology at UCSF, and Leonardo Morsut, PhD, now an assistant professor of stem cell biology and regenerative medicine at the University of Southern California.

A UCSF press release by Nick Weiler describes how synNotch was used:

“The researchers engineered cells to respond to specific signals from neighboring cells by producing Velcro-like adhesion molecules called cadherins as well as fluorescent marker proteins. Remarkably, just a few simple forms of collective cell communication were sufficient to cause ensembles of cells to change color and self-organize into multi-layered structures akin to simple organisms or developing tissues.”

Senior author Wendell Lim also explained how this system could overcome the challenges facing those aiming to build organs via 3D bioprinting technologies:

“People talk about 3D-printing organs, but that is really quite different from how biology builds tissues. Imagine if you had to build a human by meticulously placing every cell just where it needs to be and gluing it in place. It’s equally hard to imagine how you would print a complete organ, then make sure it was hooked up properly to the bloodstream and the rest of the body. The beauty of self-organizing systems is that they are autonomous and compactly encoded. You put in one or a few cells, and they grow and organize, taking care of the microscopic details themselves.”

Study was published in Science.

Stem Cell Roundup: The brain & obesity; iPSCs & sex chromosomes; modeling mental illness

Stem Cell Image of the Week:
Obesity-in-a-dish reveals mutations and abnormal function in nerve cells

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Image shows two types of hypothalamic neurons (in magenta and cyan) that were derived from human induced pluripotent stem cells.
Credit: Cedars-Sinai Board of Governors Regenerative Medicine Institute

Our stem cell image of the week looks like the work of a pre-historic cave dweller who got their hands on some DayGlo paint. But, in fact, it’s a fluorescence microscopy image of stem cell-derived brain cells from the lab of Dhruv Sareen, PhD, at Cedars-Sinai Medical Center. Sareen’s team is investigating the role of the brain in obesity. Since the brain is a not readily accessible organ, the team reprogrammed skin and blood cell samples from severely obese and normal weight individuals into induced pluripotent stem cells (iPSCs). These iPSCs were then matured into nerve cells found in the hypothalamus, an area of the brain that regulates hunger and other functions.

A comparative analysis showed that the nerve cells derived from the obese individuals had several genetic mutations and had an abnormal response to hormones that play a role in telling our brains that we are hungry or full. The Cedars-Sinai team is excited to use this obesity-in-a-dish system to further explore the underlying cellular changes that lead to excessive weight gain. Ultimately, these studies may reveal ways to combat the ever-growing obesity epidemic, as Dr. Sareen states in a press release:

“We are paving the way for personalized medicine, in which drugs could be customized for obese patients with different genetic backgrounds and disease statuses.”

The study was published in Cell Stem Cell

Differences found in stem cells derived from male vs female.

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Microscope picture of a colony of iPS cells. Credit: Vincent Pasque

Scientists at UCLA and KU Leuven University in Belgium carried out a study to better understand the molecular mechanisms that control the process of reprogramming adult cells back into the embryonic stem cell-like state of induced pluripotent stem cells (iPSCs). Previous studies have shown that female vs male embryonic stem cells have different patterns of gene regulation. So, in the current study, male and female cells were analyzed side-by-side during the reprogramming process.  First author Victor Pasquale explained in a press release that the underlying differences stemmed from the sex chromosomes:

In a normal situation, one of the two X chromosomes in female cells is inactive. But when these cells are reprogrammed into iPS cells, the inactive X becomes active. So, the female iPS cells now have two active X chromosomes, while males have only one. Our results show that studying male and female cells separately is key to a better understanding of how iPS cells are made. And we really need to understand the process if we want to create better disease models and to help the millions of patients waiting for more effective treatments.”

The CIRM-funded study was published in Stem Cell Reports.

Using mini-brains and CRISPR to study genetic linkage of schizophrenia, depression and bipolar disorder.

If you haven’t already picked up on a common thread in this week’s stories, this last entry should make it apparent: iPSC cells are the go-to method to gain insight in the underlying mechanisms of a wide range of biology topics. In this case, researchers at Brigham and Women’s Hospital at Harvard Medical School were interested in understanding how mutations in a gene called DISC1 were linked to several mental illnesses including schizophrenia, bipolar disorder and severe depression. While much has been gleaned from animal models, there’s limited knowledge of how DISC1 affects the development of the human brain.

The team used human iPSCs to grow cerebral organoids, also called mini-brains, which are three-dimensional balls of cells that mimic particular parts of the brain’s anatomy. Using CRISPR-Cas9 gene-editing technology – another very popular research tool – the team introduced DISC1 mutations found in families suffering from these mental disorders.

Compared to cells with normal copies of the DISC1 gene, the mutant organoids showed abnormal structure and excessive cell signaling. When an inhibitor of that cell signaling was added to the growing mutant organoids, the irregular structures did not develop.

These studies using human cells provide an important system for gaining a better understanding of, and potentially treating, mental illnesses that victimize generations of families.

The study was published in Translation Psychiatry and picked up by Eureka Alert.

Stem Cell Roundup: watching brain cells in real time, building better heart cells, and the plot thickens on the adult neurogenesis debate

Here are the stem cell stories that caught our eye this week.

Watching brain cells in real time

This illustration depicts a new method that enables scientists to see an astrocyte (green) physically interacting with a neuronal synapse (red) in real time, and producing an optical signal (yellow). (Khakh Lab, UCLA Health)

Our stem cell photo of the week is brought to you by the Khakh lab at UCLA Health. The lab developed a new method that allows scientists to watch brain cells interact in real time. Using a technique called fluorescence resonance energy-transfer (FRET) microscopy, the team can visualize how astrocytes (key support cells in our central nervous system) and brain cells called neurons form connections in the mouse brain and how these connections are affected by diseases like Alzheimer’s and ALS.

Baljit Khakh, the study’s first author, explained the importance of their findings in a news release:

“This new tool makes possible experiments that we have been wanting to perform for many years. For example, we can now observe how brain damage alters the way that astrocytes interact with neurons and develop strategies to address these changes.”

The study was published this week in the journal Neuron.


Turn up the power: How to build a better heart cell (Todd Dubnicoff)

For years now, researchers have had the know-how to reprogram a donor’s skin cells into induced pluripotent stem cells (iPSCs) and then specialize them into heart muscle cells called cardiomyocytes. The intervening years have focused on optimizing this method to accurately model the biology of the adult human heart as a means to test drug toxicity and ultimately develop therapies for heart disease. Reporting this week in Nature, scientists at Columbia University report an important step toward those goals.

The muscle contractions of a beating heart occur through natural electrical impulses generated by pacemaker cells. In the case of lab-grown cardiomyocytes, introducing mechanical and electrical stimulation is required to reliably generate these cells. In the current study, the research team showed that the timing and amount of stimulation is a critical aspect to the procedure.

The iPS-derived cardiomyocytes have formed heart tissue that closely mimics human heart functionality at over four weeks of maturation. Credit: Gordana Vunjak-Novakovic/Columbia University.

The team tested three scenarios on iPSC-derived cardiomyocytes (iPSC-CMs): no electrical stimulation for 3 weeks, constant stimulation for 3 weeks, and finally, two weeks of increasingly higher stimulation followed by a week of constant stimulation. This third setup mimics the changes that occur in a baby’s heart just before and just after birth.

These scenarios were tested in 12 day-old and 28 day-old iPSC-CMs. The results show that only the 12 day-old cells subjected to the increasing amounts of stimulation gave rise to fully mature heart muscle cells. On top of that, it only took four weeks to make those cells. Seila Selimovic, Ph.D., an expert at the National Institutes of Health who was not involved in the study, explained the importance of these findings in a press release:

“The resulting engineered tissue is truly unprecedented in its similarity to functioning human tissue. The ability to develop mature cardiac tissue in such a short time is an important step in moving us closer to having reliable human tissue models for drug testing.”

Read more at: https://phys.org/news/2018-04-early-bioengineered-human-heart-cells.html#jCp


Yes we do, no we don’t. More confusion over growing new brain cells as we grow older (Kevin McCormack)

First we didn’t, then we did, then we didn’t again, now we do again. Or maybe we do again.

The debate over whether we are able to continue making new neurons as we get older took another twist this week. Scientists at Columbia University said their research shows we do make new neurons in our brain, even as we age.

This image shows what scientists say is a new neuron in the brain of an older human. A new study suggests that humans continue to make new neurons throughout their lives. (Columbia University Irving Medical Center)

In the study, published in the journal Cell Stem Cell, the researchers examined the brains of 28 deceased donors aged 14 to 79. They found similar numbers of precursor and immature neurons in all the brains, suggesting we continue to develop new brain cells as we age.

This contrasts with a UCSF study published just last month which came to the opposite conclusion, that there was no evidence we make new brain cells as we age.

In an interview in the LA Times, Dr. Maura Boldrini, the lead author on the new study, says they looked at a whole section of the brain rather than the thin tissues slices the UCSF team used:

“In science, the absence of evidence is not evidence of absence. If you can’t find something it doesn’t mean that it is not there 100%.”

Well, that resolves that debate. At least until the next study.