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Autism, Mental Health, Neuroscience, Research, Science, Stanford News, Stem Cells

Brain cell spheres in a lab dish mimic human cortex, Stanford study says

Brain cell spheres in a lab dish mimic human cortex, Stanford study says

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Mental disorders like autism and schizophrenia are notoriously difficult to study at the molecular level. Understandably, people are reluctant to donate pieces of living brain for study, and postmortem tissue lets researchers see the structure, but not the function, of the cells.

Now researchers in the laboratories of psychiatrist Sergiu Pasca, MD, and neurobiologist Ben Barres, MD, PhD, have found a way to make balls of cells that mimic the activity of the human cortex. They use a person’s skin cells, so the resulting “human cortical spheroid” has the same genetic composition as the donor. The research was published in Nature Methods yesterday.

According to our release:

Previous attempts to create patient-specific neural tissue for study have either generated two-dimensional colonies of immature neurons that do not create functional synapses, or required an external matrix on which to grow the cells in a series of laborious and technically difficult steps.

In contrast, the researchers found they were able to easily make hundreds of what they’ve termed “human cortical spheroids” using a single human skin sample. These spheroids grow to be as large as 5 millimeters in diameter and can be maintained in the laboratory for nine months or more. They exhibit complex neural network activity and can be studied with techniques well-honed in animal models.

The researchers, which include neonatology fellow Anca Pasca, MD, and graduate student Steven Sloan, hope to use the technique to help understand how the human brain develops, and what sometimes goes wrong. As described by Barres:

The power and promise of this new method is extraordinary. For instance, for developmental brain disorders, one could take skin cells from any patient and literally replay the development of their brain in a culture dish to figure out exactly what step of development went awry — and how it might be corrected.

The research is starting to garner attention, including this nice article from Wired yesterday. Pasca’s eager to note, however, that he’s not working to create entire brains, which would be ethically and technically challenging, to say the least. But simply generating even a few of the cell types in the cortex will give researchers a much larger canvas with which to study some devastating conditions. As Pasca notes in our release:

I am a physician by training. We are often very limited in the therapeutic options we can offer patients with mental disorders. The ability to investigate in a dish neuronal and glial function, as well as network activity, starting from patient’s own cells, has the potential to bring novel insights into psychiatric disorders and their treatment.

Previously: More than just glue, glial cells challenge neuron’s top slot and Star-shaped cells nab new starring role in sculpting brain circuits
Photo of spheroid cross-section by Anca Pasca

Pediatrics, Research, Stanford News, Stem Cells

Near approval: A stem cell gene therapy developed by Stanford researcher

Near approval: A stem cell gene therapy developed by Stanford researcher

It has been a momentous month for Stanford researcher Maria Grazia Roncarolo, MD. Following decades of research in Roncarolo’s lab and the clinic, pharmaceutical company Glaxo SmithKline has applied for final approval by European Medicines Agency (EMA) of a treatment she developed to cure a deadly childhood immune disorder. If approved by the EMA, which is Europe’s equivalent of the U.S. Food and Drug Administration (FDA), the treatment would be the first gene stem cell therapy to be granted approval by a major medical regulatory agency.

The therapy cures a disease called severe combined immune deficiency (SCID), sometimes called the “bubble boy disease,” by inserting a gene into blood stem cells and transplanting the stem cells into the patient’s body. The treatment is still being evaluated by the FDA.

My greatest satisfaction is that kids who were once incurable now have options

If approved, the treatment will no longer be considered an experimental therapy in Europe, and “people will be able to get this treatment as they would any other, and will be able to get their insurance company to pay for it,” Roncarolo told me. The final regulatory review marks the beginning of a new era in which genetically modified stem cells might be used to treat or cure a wide variety of human diseases, she also noted.

Roncarolo developed the treatment while she was scientific director at the San Raffaele Scientific Institute in Milan, Italy. There, she treated kids who were born with an inability to make the enzyme adenosine deaminase (ADA), which leaves them unable to make certain immune cells that protect them from infection. For that reason, children with ADA-SCID are forced to spend their lives in a sterile environment that protects them from infections that most people would easily fight off but are deadly for them.

Roncarolo and her team inserted the gene for ADA into blood stem cells which were transplanted into 18 children with the disease. Once the modified blood stem cells could produce the enzyme, they were able to form the necessary immune cells and the children were able to leave their sterile environment. “Those children have been effectively cured,” Roncarolo said.

Other gene therapies have been developed before, but those therapies modified more mature cells that cannot reproduce themselves. Only stem cells can both make more copies of themselves and also produce more specialized cells. If gene therapy is used to modify cells that are not stem cells, the treatment will only last as long as the cells last. Eventually, mature cells age and die, and the disorder returns.

Last year, Roncarolo was recruited to Stanford to continue her work while serving as co-director of the Institute for Stem Cell Biology and Regenerative Medicine. She is busy researching cures for other congenital immune disorders and developing methods that could lead to stem cell treatments for a wide variety of other diseases.

“My greatest satisfaction is that kids who were once incurable now have options,” Roncarolo said.

Previously: Countdown to Childx: Stanford expert highlights future of stem cell and gene therapies

Bioengineering, Imaging, Neuroscience, Research, Stanford News, Stem Cells

New way to watch what stem cells transplanted into the brain do once they get there

New way to watch what stem cells transplanted into the brain do once they get there

binocularsStem cell replacement therapy is a promising but problem-plagued medical intervention.

In a recent news release detailing a possible way forward, I wrote:

Many brain disorders, such as Parkinson’s disease, are characterized by defective nerve cells in specific brain regions. This makes disorders such as Parkinson’s excellent candidates for stem cell therapies, in which the defective nerve cells are replaced. But the experiments in which such procedures have been attempted have met with mixed results, and those conducting the experiments are hard put to explain them.

That’s because there’s been no good way to evaluate what those transplanted stems cells are doing once you’ve put them inside a living individual. I mean, you’re not gonna break into someone’s brain every couple of days to take a peek, right? Instead, you have to look for behavioral changes. Is the patient or experimental animal walking better (if you’re trying to treat Parkinson’s), or (if it’s Alzheimer’s) remembering better ? Then, even when you see those changes, you still don’t know whether new nerve cells derived from the newly transplanted cells integrated into the proper brain circuits and are now functioning correctly there, or whether the originally transplanted cells are just sitting around secreting some kind of feel-good factor to pep up ailing cells in the vicinity, juicing their  performance. Or maybe it was a placebo effect.

It’s hard to improve on a procedure when you don’t really know what went wrong – or even what went right – on the last attempt. Optimizing the regimen becomes a matter of guesswork and luck.

But in a new study in NeuroImage, neuroscientist/bioengineer Jin Hyung Lee, PhD, and her colleagues came up with a way to peer deep into the living brain and view the results of a stem-cell transplant procedure. They combined an established brain-imaging technique with a newer but increasingly widespread one, called optogenetics, that lets researchers stimulate specific cells.

The first step in optogenetics is to genetically modify the cells you want to stimulate, so that their surfaces become coated by a photosensitive protein that generates electric current in response to laser light. Lee’s team performed this operation on the stem cells before transplanting them into rats’ brains. This way, they could selectively stimulate nerve cells derived from those stem cells and,  using the brain-imaging technique, see if doing so triggered nerve-cell activity at the site of the transplant as well as other places in the brain with which the new cells had established connections.

In these experiments, the stem-cell-derived nerve cells survived, matured into nerve cells, integrated into targeted brain circuits and, most important, fired on cue and ignited activity in downstream nerve circuits. But had all that not happened, at least the researchers would have been able to pinpoint the weak link in the chain.

In principle, the new approach should be possible to use for all kinds of stem-cell therapies, and in humans as well as animals. As Lee told me when I interviewed her for my release on her new study, “If we can watch the new cells’ behaviors for weeks and months after we’ve transplanted them, we can learn – much more quickly and in a guided way rather than a trial-and-error fashion – what kind of cells to put in, exactly where to put them, and how.”

If this light-driven stem-cell-monitoring technique or some others I’ve reported on hold up, brave explorers may no longer have to poke around in the dark.

Previously: Alchemy: From liposuction fluid to new liver cells, Iron-supplement-slurping stem cells can be transplanted, then tracked to make sure they’re making new knees, You’ve got a lot of nerve! Industrial-scale procedure for generating plenty of personalized nerve cells and Nano-hitchhikers ride stem cells into heart, let researchers watch in real time and weeks later
Photo by Nicki Dugan Pogue

AHCJ15, Science, Science Policy, Stem Cells

Stanford stem cell experts highlight “inherent flaw” in drug development system

Stanford stem cell experts highlight "inherent flaw" in drug development system

Academic institutions are in a much better position than pharmaceutical companies to make the best decisions about which therapies deserve further development. That was the underlying message from a pair of Stanford researchers at a panel on stem cell science at last weekend’s Association of Health Care Journalism 2015 conference.

“There’s an inherent flaw in our system,” said Irving Weissman, MD, director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine. “Companies are driven by the desire for profits rather than the desire to find the best therapy, and they often give up on discoveries too early.”

Weissman cited studies that were done long ago at Stanford and proven in mouse models or human clinical trials that pharmaceutical companies have failed to develop. “In mice, transplantation of purified blood stem cell and insulin producing cells from closely related mice leads to a permanent cure,” Weissman says. “We discovered that 16 years ago, and a therapy is still not available.”

A therapy involving high-dose chemotherapy followed by purified stem cell transplant for stage 4 breast cancer cured a relatively high number of women in a small trial almost 20 years ago but the pharmaceutical company with the rights to the technology decided not to develop the treatment, Weissman says. A larger trial of this therapy is currently being planned at Stanford.

Maria Grazia Roncarolo, MD, co-director of the institute, spoke about her own experience in an academic environment developing therapies for diseases that pharmaceutical companies deem to rare to merit their attention. Only after she showed that a therapy for severe combined immune deficiency could work did pharmaceutical companies get interested.

“Academic researchers should have the ability to test a therapy, to have control of the design and execution of the clinical trials, and pharmaceutical companies should do the production and marketing,” Roncarolo told the journalists attending the session.

Allowing academic institutions to run clinical trials is “a big effort that will require a team, institutional commitment and robust funding,” Roncarolo said. Comparing the situation in the United States to that in Europe, where she has done much of her research, she notes that “in this country there is little funding for proof of concept trials to bring therapies from the lab bench to the bedside.”

Previously: An inside look at drug development, Stanford’s Irving Weissman on the (lost?) promise of stem cells and The largest stem cell research building in the U.S.

Evolution, Genetics, Microbiology, Pregnancy, Research, Science, Stanford News, Stem Cells

My baby, my… virus? Stanford researchers find viral proteins in human embryonic cells

My baby, my... virus? Stanford researchers find viral proteins in human embryonic cells

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One thing I really enjoy about my job is the opportunity to constantly be learning something new. For example, I hadn’t realized that about eight percent of human DNA is actually left-behind detritus from ancient viral infections. I knew they were there, but eight percent? That’s a lot of genetic baggage.

These sequences are often inactive in mature cells, but recent research has shown they can become activated in some tumor cells or in human embryonic stem cells. Now developmental biologist Joanna Wysocka, PhD, and graduate student Edward Grow, have shown that some of these viral bits and pieces spring back to life in early human embryos and may even affect their development.

Their research was published today in Nature. As I describe in our press release:

Retroviruses are a class of virus that insert their DNA into the genome of the host cell for later reactivation. In this stealth mode, the virus bides its time, taking advantage of cellular DNA replication to spread to each of an infected cell’s progeny every time the cell divides. HIV is one well-known example of a retrovirus that infects humans.

When a retrovirus infects a germ cell, which makes sperm and eggs, or infects a very early-stage embryo before the germ cells have arisen, the viral DNA is passed along to future generations. Over evolutionary time, however, these viral genomes often become mutated and inactivated. About 8 percent of the human genome is made up of viral sequences left behind during past infections. One retrovirus, HERVK, however, infected humans repeatedly relatively recently — within about 200,000 years. Much of HERVK’s genome is still snuggled, intact, in each of our cells.

Wysocka and Grow found that human embryonic cells begin making viral proteins from these HERVK sequences within just a few days after conception. What’s more, the non-human proteins have a noticeable effect on the cells, increasing the expression of a cell surface protein that makes them less susceptible to subsequent viral infection and also modulating human gene expression.

More from our release:

But it’s not clear whether this sequence of events is the result of thousands of years of co-existence, a kind of evolutionary symbiosis, or if it represents an ongoing battle between humans and viruses.

“Does the virus selfishly benefit by switching itself on in these early embryonic cells?” said Grow. “Or is the embryo instead commandeering the viral proteins to protect itself? Can they both benefit? That’s possible, but we don’t really know.”

Wysocka describes the findings as “fascinating, but a little creepy.” I agree. But I can’t wait to hear what they discover next.

Previously: Viruses can cause warts on your DNA, Stanford researcher wins Vilcek Prize for Creative Promise in Biomedical Science and Species-specific differences among placentas due to long-ago viral infection, say Stanford researchers
Photo of Joanna Wysocka by Steve Fisch

otolaryngology, Research, Science, Stanford News, Stem Cells

Molecular sleuthing uncovers new clue toward deafness cure

Molecular sleuthing uncovers new clue toward deafness cure

In another step along the path toward finding cures for deafness, Stanford scientists report they have discovered a subset of cells in the mammalian utricle, the inner ear structure that controls balance, that can regenerate into hair cells when damaged.

The study was published today in Nature Communications, and senior author Alan Cheng, MD, explained the significance of the findings to me this way:

We rely on our inner ear sensory organs to hear and sense motion. Such functions require specialized hair cells to detect the vibrations of sound or motion. Once lost, hair cells needed for hearing do not regenerate and thus hearing loss is permanent, while those to sense motion can regenerate to a limited degree. Until now, the origin of these regenerated hair cells and the mechanisms that limit this process of regeneration in the utricle have not been clear. Here, we found two distinct populations of such hair cell progenitors in the neonatal mouse utricle, where they can regenerate lost hair cells. Unlike the utricle from older mice, the degree of regeneration and also cell division at this age are a lot more robust.

The study also provides an improved understanding of the molecular pathway that leads to this transformation, knowledge that could maybe one day be used to help researchers figure out how to artificially encourage hair cell renewal in humans.

Previously: Understanding hearing loss at the molecular level, New version of popular antibiotic eliminates side effect of deafness and Stanford chair of otolarnygology discusses future regenerative therapies for hearing loss

Events, Genetics, Patient Care, Pediatrics, Research, Stanford News, Stem Cells

“It’s not just science fiction anymore”: Childx speakers talk stem cell and gene therapy

“It’s not just science fiction anymore": Childx speakers talk stem cell and gene therapy

childx PorteusAt the Childx conference last week there was a great deal of optimism that stem cell and genetic therapies are about to have a huge impact on many childhood diseases. “It’s not just science fiction anymore,” Matthew Porteus, MD, PhD, told the audience. “We can correct mutations that cause childhood disease.”

The session was hosted by Stanford professor Maria Grazia Roncarolo, MD, who until recently was head of the Italy’s Telethon Institute for Cell and Gene Therapy at the San Raffaele Scientific Institute in Milan. Roncarolo pointed out that there are more than 10,000 human diseases that are caused by a single gene defect. “Stem cell and gene therapies can be used to treat cancer and other diseases,” Roncarolo said.

Two such diseases are sickle cell disease and severe combined immune deficiency. In both cases, a single nucleotide change in DNA becomes a deadly defect for children with the bad luck to have them. Porteus is working on very new genome editing technologies that allow clinicians to go in and fix those DNA typos and cure diseases.

Stanford dermatology researcher Anthony Oro, MD, PhD is working to do something similar with skin cells for a painful blistering disease called epidermolysis bullosa. Children with EB lack a functional gene for one of the proteins that anchors the layers of skin together. Oro and Stanford Institute for Stem Cell Biology and Regenerative Medicine scientist Marius Wernig, MD, PhD, are taking defective skin cells from patients, transforming them into embryonic-like stem cells, fixing the gene defect, and then growing them back into skin stem cells and then layers of skin ready for transplantation. Oro says that they have shown that they can do this in a scalable way in mice, and they hope to start a clinical trial in humans soon.

One of the challenges to genetic therapy is that it often requires putting the gene into blood stem cells to deliver it to the body, but the high dose chemotherapy or radiation that is necessary to remove the bodies own blood stem cells and make way for the transplanted cells is very dangerous in itself. Researchers like Stanford researcher Hiromitsu Nakuchi, MD, PhD, are exploring gentler ways to make space in the body for the transplanted cells. He has discovered that simply by feeding mice a diet deficient in a particular amino acid, blood stem cells begin to die. Other cells in the body don’t seem to be as strongly affected. A dietary solution may eventually allow clinicians to avoid using the highly toxic treatments that have traditionally been used for blood stem cell transplant.

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Research, Science, Stanford News, Stem Cells

Bridging the stem-cell gap: Stanford researchers identify unique transition state

Bridging the stem-cell gap: Stanford researchers identify unique transition state

474026463_87cca6b272_zIn 2006, Shinya Yamanaka, MD, PhD, turned the stem-cell world upside down when he showed it was possible to take mature, specialized cells such as those found in skin and convert them to a pluripotent state simply by exposing them to a few key proteins. The discovery earned Yamanaka the Nobel Prize in Physiology or Medicine in 2012 and sparked an explosion of stem-cell science.

Although the exact steps of the reprogramming process are unknown, scientists have thought it proceeded mostly as a two-step pathway that essentially rewinds the march to specialization that normally occurs during development. Now Marius Wernig, MD, and his colleagues at the Stanford Institute for Stem Cell Biology and Regenerative Medicine have uncovered an intermediary state through which the cells must pass to successfully acquire pluripotency (a term that describes a cell’s ability to become nearly any cell type in the body). The researchers published their findings in today’s  Nature.

As Wernig described in my article on the research:

This [finding] was completely unexpected. It’s always been assumed that reprogramming is simply a matter of pushing mature cells backward along the developmental pathway. These cells would undergo two major changes: they’d turn off genes corresponding to their original identity, and begin to express pluripotency genes. Now we know there’s an intermediary state we’d never imagined before.

Cells in this “bridge” state express cell surface markers that are distinct from those found on fibroblasts (the starting cell type) and on successfully reprogrammed iPS cells. They also express specific transcription factors that likely contribute to the cells’ progression through the reprogramming process.

The researchers believe it may be possible to increase the efficiency of reprogramming in cells that typically resist the process (these cell types include highly specialized cells or cancer cells). But they’re more excited about peeking into the inner workings of a transformation that’s been both revolutionary and mysterious.

“We’re learning more and more about how cells accomplish this really unbelievable task of reverting to pluripotency,” Wernig told me. “Now we know that the cell biology of this process is novel, and this intermediary state is unique.”

Previously: Congratulations to Marius Wernig, named Outstanding Young Investigator by stem cell society, The end of iPS? Stanford scientists directly convert mouse skin cells to neural precursors and Human neurons from skin cells without pluripotency?
Photo by Alexis R

Genetics, Pediatrics, Podcasts, Research, Stem Cells

Countdown to Childx: Stanford expert highlights future of stem cell and gene therapies

Countdown to Childx: Stanford expert highlights future of stem cell and gene therapies

RoncaroloNext month’s inaugural Childx conference will bring a diverse group of experts to Stanford to discuss big challenges in infant, child and maternal health. Today, in a new 1:2:1 podcast interview, stem cell and gene therapy expert Maria Grazia Roncarolo, MD, provides an interesting preview of a once-controversial area of research that will be featured at the conference.

Roncarolo talks about the history and future of stem cell and gene therapy treatments, which have recovered from tragic setbacks such as the 1999 death of 18-year-old Jesse Gelsinger in an early gene therapy trial. The early problems forced researchers to reevaluate what they were doing, with the result that the entire field has reemerged stronger, she explains:

I would say that there were major problems, that we underestimated the complexity that it takes to manipulate the genome, and to introduce a healthy gene to fix a genetic disease. However, from these mistakes and from these tragedies, we learned a lot. We were really forced as doctors, and more importantly, as scientists, to go back to the bench and develop better technologies and to understand more of what was required. … [Today] we use better vectors — which are the carriers to introduce the healthy gene — we know much more about what we have to do to prepare the patient to receive the gene therapy, and we also learned that we need to do a very careful monitoring of the patients to really understand where the gene lands in the genome.

At the Childx conference, Roncarolo will moderate a panel on “Definitive Stem Cell and Gene Therapy for Child Health,” hosting such guests as GlaxoSmithKline’s senior vice president of rare diseases, Martin Andrews, and Nadia Rosenthal, PhD, founding director of the Australian Regenerative Medicine Institute.

Information about registration for Childx, being held here April 2–3, is available on the conference website.

Previously: Stanford hosts inaugural Childx conference this spring and Stanford researchers receive $40 million from state stem cell agency
Photo by Norbert von der Groeben

Cancer, Stanford News, Stem Cells, Videos

A look at stem cells and “chemobrain”

A look at stem cells and "chemobrain"

As many as 75 percent of cancer patients experience memory and attention problems during or after their treatment, and up to 3.9 million are afflicted by long-term cognitive dysfunction. This foggy mental state, often referred to as “chemobrain,” can also affect cancer survivors’ fine motor skills, information processing speed, concentration and ability to calculate.

In this recently posted California Institute for Regenerative Medicine video, Stanford physician-scientist Michelle Monje, MD, PhD, explains the role that damage to stem cells in the brain plays in the condition, outlines some of the interventions that can mitigate patients’ symptoms, and highlights efforts to develop effective regenerative therapies.

Previously: Stanford brain tumor research featured on “Bay Area Proud”, Emmy nod for film about Stanford brain tumor research – and the little boy who made it possible and Stanford study shows effects of chemotherapy and breast cancer on brain function

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