Stem Cell Stories that Caught our Eye: CRISPRing Human Embryos, brain stem cells slow aging & BrainStorm ALS trial joins CIRM Alpha Clinics

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

Scientists claim first CRISPR editing of human embryos in the US.

Here’s the big story this week. Scientists from Portland, Oregon claim they genetically modified human embryos using the CRISPR/Cas9 gene editing technology. While their results have yet to be published in a peer review journal (though the team say they are going to be published in a prominent journal next month), if they prove true, the study will be the first successful attempt to modify human embryos in the US.

A representation of an embryo being fertilized. Scientists can inject CRISPR during fertilization to correct genetic disorders. (Getty Images).

Steve Connor from MIT Technology Review broke the story earlier this week noting that the only reports of human embryo modification were published by Chinese scientists. The China studies revealed troubling findings. CRISPR caused “off-target” effects, a situation where the CRISPR machinery randomly introduces genetic errors in a cell’s DNA, in the embryos. It also caused mosaicism, a condition where the desired DNA sequences aren’t genetically corrected in all the cells of an embryo producing an individual with cells that have different genomes. Putting aside the ethical conundrum of modifying human embryos, these studies suggested that current gene editing technologies weren’t accurate enough to safely modify human embryos.

But a new chapter in human embryo modification is beginning. Shoukhrat Mitalipov (who is a member of CIRM’s Grants Working Group, the panel of scientific experts that reviews our funding applications) and his team from the Oregon Health and Science University said that they have developed a method to successfully modify donated human embryos that avoids the problems experienced by the Chinese scientists. The team found that introducing CRISPR at the same time an embryo was being fertilized led to successful correction of disease-causing mutations while avoiding mosaicism and “off-target” effects. They grew these embryos for a few days to confirm that the genetic modifications had worked before destroying them.

The MIT piece quoted a scientist who knows of Mitalipov’s work,

“It is proof of principle that it can work. They significantly reduced mosaicism. I don’t think it’s the start of clinical trials yet, but it does take it further than anyone has before.”

Does this discovery, if it’s true, open the door further for the creation of designer babies? For discussions about the future scientific and ethical implications of this research, I recommend reading Paul Knoepfler’s blog, this piece by Megan Molteni in Wired Magazine and Jessica Berg’s article in The Conversation.

Brain stem cells slow aging in mice

The quest for eternal youth might be one step closer thanks to a new study published this week in the journal Nature. Scientists from the Albert Einstein College of Medicine in New York discovered that stem cells found in an area of the brain called the hypothalamus can slow the aging process in mice.

The hypothalamus is located smack in the center of your brain near the brain stem. It’s responsible for essential metabolic functions such as making and secreting hormones, managing body temperature and controlling feelings of hunger and thirst. Because the body’s metabolic functions decline with age, scientists have suspected that the hypothalamus plays a role in aging.

The mouse hypothalamus. (NIH, Wikimedia).

In the current study, the team found that stem cells in the hypothalamus gradually disappear as mice age. They were curious whether the disappearance of these stem cells could jump start the aging process. When they removed these stem cells, the mice showed more advanced mental and physical signs of aging compared to untreated mice.

They also conducted the opposite experiment where they transplanted hypothalamic stem cells taken from baby mice (the idea being that these stem cells would exhibit more “youthful” qualities) into the brains of middle-aged mice and saw improvements in mental and physical functions and a 10% increase in lifespan.

So what is it about these specific stem cells that slows down aging? Do they replenish the aging brain with new healthy cells or do they secrete factors that keep the brain healthy? Interestingly, the scientists found that these stem cells secreted vesicles that contained microRNAs, which are molecules that regulate gene expression by turning genes on or off.

They injected these microRNAs into the brains of middle-aged mice and found that they reversed symptoms of aging including cognitive decline and muscle degeneration. Furthermore, when they removed hypothalamic stem cells from middle-aged mice and treated them with the microRNAs, they saw the same anti-aging effects.

In an interview with Nature News, senior author on the study, Dongsheng Cai, commented that hypothalamic stem cells could have multiple ways of regulating aging and that microRNAs are just one of their tools. For this research to translate into an anti-aging therapy, “Cai suspects that anti-ageing therapies targeting the hypothalamus would need to be administered in middle age, before a person’s muscles and metabolism have degenerated beyond a point that could be reversed.”

This study and its “Fountain of Youth” implications has received ample attention from the media. You can read more coverage from The Scientist, GenBio, and the original Albert Einstein press release.

BrainStorm ALS trial joins the CIRM Alpha Clinics

Last month, the CIRM Board approved $15.9 million in funding for BrainStorm Cell Therapeutic’s Phase 3 trial that’s testing a stem cell therapy to treat patients with a devastating neurodegenerative disease called amyotrophic lateral sclerosis or ALS (also known as Lou Gehrig’s disease).

The stem cell therapy, called NurOwn®, is made of mesenchymal stem cells extracted from a patient’s bone marrow. The stem cells are genetically modified to secrete neurotrophic factors that keep neurons in the brain healthy and prevent their destruction by diseases like ALS.

BrainStorm has tested NurOwn in early stage clinical trials in Israel and in a Phase 2 study in the US. These trials revealed that the treatment was “safe and well tolerated” and that “NurOwn also achieved multiple secondary efficacy endpoints, showing clear evidence of a clinically meaningful benefit.  Notably, response rates were higher for NurOwn-treated subjects compared to placebo at all time points in the study out to 24 weeks.”

This week, BrainStorm announced that it will launch its Phase 3 CIRM-funded trial at the UC Irvine (UCI) CIRM Alpha Stem Cell Clinic. The Alpha Clinics are a network of top medical centers in California that specialize in delivering high quality stem cell clinical trials to patients. UCI is one of four medical centers including UCLA, City of Hope, and UCSD, that make up three Alpha Clinics currently supporting 38 stem cell trials in the state.

Along with UCI, BrainStorm’s Phase 3 trial will also be conducted at two other sites in the US: Mass General Hospital in Boston and California Pacific Medical Center in San Francisco. Chaim Lebovits, President and CEO, commented,

“We are privileged to have UCI and Dr. Namita Goyal join our pivotal Phase 3 study of NurOwn. Adding UCI as an enrolling center with Dr. Goyal as Principal Investigator will make the treatment more accessible to patients in California, and we welcome the opportunity to work with this prestigious institution.”

Before the Phase 3 trial can launch at UCI, it needs to be approved by our federal regulatory agency, the Food and Drug Administration (FDA), and an Institutional Review Board (IRB), which is an independent ethics committee that reviews biomedical research on human subjects. Both these steps are required to ensure that a therapy is safe to test in patients.

With promising data from their Phase 1 and 2 trials, BrainStorm’s Phase 3 trial will likely get the green light to move forward. Dr. Goyal, who will lead the trial at the UCI Alpha Clinic, concluded:

“NurOwn is a very promising treatment with compelling Phase 2 data in patients with ALS; we look forward to further advancing it in clinical development and confirming the therapeutic benefit with Brainstorm.”

Stem cell stories that caught our eye: developing the nervous system, aging stem cells and identical twins not so identical

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

New theory for how the nervous system develops.

There’s a new theory on the block for how the nervous system is formed thanks to a study published yesterday by UCLA stem cell scientists in the journal Neuron.

The theory centers around axons, thin extensions projecting from nerve cells that transmit electrical signals to other cells in the body. In the developing nervous system, nerve cells extend axons into the brain and spinal cord and into our muscles (a process called innervation). Axons are guided to their final destinations by different chemicals that tell axons when to grow, when to not grow, and where to go.

Previously, scientists believed that one of these important chemical signals, a protein called netrin 1, exerted its influence over long distances in a gradient-like fashion from a structure in the developing nervous system called the floor plate. You can think of it like a like a cell phone tower where the signal is strongest the closer you are to the tower but you can still get some signal even when you’re miles away.

The UCLA team, led by senior author and UCLA professor Dr. Samantha Butler, questioned this theory because they knew that neural progenitor cells, which are the precursors to nerve cells, produce netrin1 in the developing spinal cord. They believed that the netrin1 secreted from these progenitor cells also played a role in guiding axon growth in a localized manner.

To test their hypothesis, they studied neural progenitor cells in the developing spines of mouse embryos. When they eliminated netrin1 from the neural progenitor cells, the axons went haywire and there was no rhyme or reason to their growth patterns.

Left: axons (green, pink, blue) form organized patterns in the normal developing mouse spinal cord. Right: removing netrin1 results in highly disorganized axon growth. (UCLA Broad Stem Cell Research Center/Neuron)

A UCLA press release explained what the scientists discovered next,

“They found that neural progenitors organize axon growth by producing a pathway of netrin1 that directs axons only in their local environment and not over long distances. This pathway of netrin1 acts as a sticky surface that encourages axon growth in the directions that form a normal, functioning nervous system.”

Like how ants leave chemical trails for other ants in their colony to follow, neural progenitor cells leave trails of netrin1 in the spinal cord to direct where axons go. The UCLA team believes they can leverage this newfound knowledge about netrin1 to make more effective treatments for patients with nerve damage or severed nerves.

In future studies, the team will tease apart the finer details of how netrin1 impacts axon growth and how it can be potentially translated into the clinic as a new therapeutic for patients. And from the sounds of it, they already have an idea in mind:

“One promising approach is to implant artificial nerve channels into a person with a nerve injury to give regenerating axons a conduit to grow through. Coating such nerve channels with netrin1 could further encourage axon regrowth.”

Age could be written in our stem cells.

The Harvard Gazette is running an interesting series on how Harvard scientists are tackling issues of aging with research. This week, their story focused on stem cells and how they’re partly to blame for aging in humans.

Stem cells are well known for their regenerative properties. Adult stem cells can rejuvenate tissues and organs as we age and in response to damage or injury. However, like most house hold appliances, adult stem cells lose their regenerative abilities or effectiveness over time.

Dr. David Scadden, co-director of the Harvard Stem Cell Institute, explained,

“We do think that stem cells are a key player in at least some of the manifestations of age. The hypothesis is that stem cell function deteriorates with age, driving events we know occur with aging, like our limited ability to fully repair or regenerate healthy tissue following injury.”

Harvard scientists have evidence suggesting that certain tissues, such as nerve cells in the brain, age sooner than others, and they trigger other tissues to start the aging process in a domino-like effect. Instead of treating each tissue individually, the scientists believe that targeting these early-onset tissues and the stem cells within them is a better anti-aging strategy.

David Sadden, co-director of the Harvard Stem Cell Institute.
(Jon Chase/Harvard Staff Photographer)

Dr. Scadden is particularly interested in studying adult stem cell populations in aging tissues and has found that “instead of armies of similarly plastic stem cells, it appears there is diversity within populations, with different stem cells having different capabilities.”

If you lose the stem cell that’s the best at regenerating, that tissue might age more rapidly.  Dr. Scadden compares it to a game of chess, “If we’re graced and happen to have a queen and couple of bishops, we’re doing OK. But if we are left with pawns, we may lose resilience as we age.”

The Harvard Gazette piece also touches on a changing mindset around the potential of stem cells. When stem cell research took off two decades ago, scientists believed stem cells would grow replacement organs. But those days are still far off. In the immediate future, the potential of stem cells seems to be in disease modeling and drug screening.

“Much of stem cell medicine is ultimately going to be ‘medicine,’” Scadden said. “Even here, we thought stem cells would provide mostly replacement parts.  I think that’s clearly changed very dramatically. Now we think of them as contributing to our ability to make disease models for drug discovery.”

I encourage you to read the full feature as I only mentioned a few of the highlights. It’s a nice overview of the current state of aging research and how stem cells play an important role in understanding the biology of aging and in developing treatments for diseases of aging.

Identical twins not so identical (Todd Dubnicoff)

Ever since Takahashi and Yamanaka showed that adult cells could be reprogrammed into an embryonic stem cell-like state, researchers have been wrestling with a key question: exactly how alike are these induced pluripotent stem cells (iPSCs) to embryonic stem cells (ESCs)?

It’s an important question to settle because iPSCs have several advantages over ESCs. Unlike ESCs, iPSCs don’t require the destruction of an embryo so they’re mostly free from ethical concerns. And because they can be derived from a patient’s cells, if iPSC-derived cell therapies were given back to the same patient, they should be less likely to cause immune rejection. Despite these advantages, the fact that iPSCs are artificially generated by the forced activation of specific genes create lingering concerns that for treatments in humans, delivering iPSC-derived therapies may not be as safe as their ESC counterparts.

Careful comparisons of DNA between iPSCs and ESCs have shown that they are indeed differences in chemical tags found on specific spots on the cell’s DNA. These tags, called epigenetic (“epi”, meaning “in addition”) modifications can affect the activity of genes independent of the underlying genetic sequence. These variations in epigenetic tags also show up when you compare two different preparations, or cell lines, of iPSCs. So, it’s been difficult for researchers to tease out the source of these differences. Are these differences due to the small variations in DNA sequence that are naturally seen from one cell line to the other? Or is there some non-genetic reason for the differences in the iPSCs’ epigenetic modifications?

Marian and Vivian Brown, were San Francisco’s most famous identical twins. Photo: Christopher Michel

A recent CIRM-funded study by a Salk Institute team took a clever approach to tackle this question. They compared epigenetic modifications between iPSCs derived from three sets of identical twins. They still found several epigenetic variations between each set of twins. And since the twins have identical DNA sequences, the researchers could conclude that not all differences seen between iPSC cell lines are due to genetics. Athanasia Panopoulos, a co-first author on the Cell Stem Cell article, summed up the results in a press release:

“In the past, researchers had found lots of sites with variations in methylation status [specific term for the epigenetic tag], but it was hard to figure out which of those sites had variation due to genetics. Here, we could focus more specifically on the sites we know have nothing to do with genetics. The twins enabled us to ask questions we couldn’t ask before. You’re able to see what happens when you reprogram cells with identical genomes but divergent epigenomes, and figure out what is happening because of genetics, and what is happening due to other mechanisms.”

With these new insights in hand, the researchers will have a better handle on interpreting differences between individual iPSC cell lines as well as their differences with ESC cell lines. This knowledge will be important for understanding how these variations may affect the development of future iPSC-based cell therapies.

Could revving up stem cells help senior citizens heal as fast as high school seniors?

All physicians, especially surgeons, sport medicine doctors, and military medical corps share a similar wish: to able to speed up the healing process for their patients’ incisions and injuries. Data published this week in Cell Reports may one day fulfill that wish. The study – reported by a Stanford University research team – pinpoints a single protein that revs up stem cells in the body, enabling them to repair tissue at a quicker rate.

Screen Shot 2017-04-19 at 5.37.38 PM

Muscle fibers (dark areas surrounding by green circles) are larger in mice injected with HGFA protein (right panel) compared to untreated mice (left panel), an indication of faster healing after muscle injury.
(Image: Cell Reports 19 (3) p. 479-486, fig 3C)

Most of the time, adult stem cells in the body keep to themselves and rarely divide. This calmness helps preserve this important, small pool of cells and avoids unnecessary mutations that may happen whenever DNA is copied during cell division.

To respond to injury, stem cells must be primed by dividing one time, which is a very slow process and can take several days. Once in this “alert” state, the stem cells are poised to start dividing much faster and help repair damaged tissue. The Stanford team, led by Dr. Thomas Rando, aimed to track down the signals that are responsible for this priming process with the hope of developing drugs that could help jump-start the healing process.

Super healing serum: it’s not just in video games
The team collected blood serum from mice two days after the animals had been subjected to a muscle injury (the mice were placed under anesthesia during the procedure and given pain medication afterwards). When that “injured” blood was injected into a different set of mice, their muscle stem cells became primed much faster than mice injected with “uninjured” blood.

“Clearly, blood from the injured animal contains a factor that alerts the stem cells,” said Rando in a press release. “We wanted to know, what is it in the blood that is doing this?”

 

A deeper examination of the priming process zeroed in on a muscle stem cell signal that is turned on by a protein in the blood called hepatocyte growth factor (HGF). So, it seemed likely that HGF was the protein that they had been looking for. But, to their surprise, there were no differences in the amount of HGF found in blood from injured and uninjured mice.

HGFA: the holy grail of healing?
It turns out, though, that HGF must first be chopped in two by an enzyme called HGFA to become active. When the team went back and examined the injured and uninjured blood, they found that it was HGFA which showed a difference: it was more active in the injured blood.

To show that HGFA was directly involved in stimulating tissue repair, the team injected mice with the enzyme two days before the muscle injury procedure. Twenty days post injury, the mice injected with HGFA had regenerated larger muscle fibers compared to untreated mice. Even more telling, nine days after the HGFA treatment, the mice had better recovery in terms of their wheel running activity compared to untreated mice.

To mimic tissue repair after a surgery incision, the team also looked at the impact of HGFA on skin wound healing. Like the muscle injury results, injecting animals with HGFA two days before creating a skin injury led to better wound healing compared to untreated mice. Even the hair that had been shaved at the surgical site grew back faster. First author Dr. Joseph Rodgers, now at USC, summed up the clinical implications of these results :

“Our research shows that by priming the body before an injury you can speed the process of tissue repair and recovery, similar to how a vaccine prepares the body to fight infection. We believe this could be a therapeutic approach to improve recovery in situations where injuries can be anticipated, such as surgery, combat or sports.”

Could we help senior citizens heal as fast as high school seniors?
Another application for this therapeutic approach may be for the elderly. Lots of things slow down when you get older including your body’s ability to heal itself. This observation sparks an intriguing question for Rando:

“Stem cell activity diminishes with advancing age, and older people heal more slowly and less effectively than younger people. Might it be possible to restore youthful healing by activating this [HGFA] pathway? We’d love to find out.”

I bet a lot of people would love for you to find out, too.

Stem Cell Stories that caught our eye: a womb with a view, reversing aging and stabilizing stem cells

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Today we bring you a trifecta of stem cell stories that were partially funded by grants from CIRM.

A womb with a view: using 3D imaging to observe embryo implantation. Scientists have a good understanding of how the beginning stages of pregnancy happen. An egg cell from a woman is fertilized by a sperm cell from a man and the result is a single cell called a zygote. Over the next week, the zygote divides into multiple cells that form the developing embryo. At the end of that period, the embryo hatches out of its protective membrane and begins implanting itself into the lining of the mother’s uterus.

It’s possible to visualize the early stages of embryo development in culture dishes, which has helped scientists understand the biological steps required for an embryo to survive and develop into a healthy fetus. However, something that is not easy to observe is the implantation stage of the embryo in the uterus. This process is complex and involves a restructuring of the uterine wall to accommodate the developing embryo. As you can imagine, replicating these events would be extremely complicated and difficult to do in a culture dish, and current imaging techniques aren’t adequate either.

That’s where new CIRM-funded research from a team at UCSF comes to the rescue. They developed a 3D imaging technology and combined it with a previously developed “tissue clearing” method, which uses chemicals to turn tissues translucent, to provide clear images of the uterine wall during embryo implantation in mice. Their work was published this week in the journal Development.

According to a UCSF news release,

“Using their new approach, the team observed that the uterine lining becomes extensively folded as it approaches its window of receptivity for an embryo to implant. The geometry of the folds in which the incoming embryos dwell is important, the team found, as genetic mutants with defects in implantation have improper patterns of folding.”

Ultimately, the team aims to use their new imaging technology to get an inside scoop on how to prevent or treat pregnancy disorders and also how to improve the outcome of pregnancies by in vitro fertilization.

Senior author on the study, UCSF professor Diana Laird concluded:

“This new view of early pregnancy lets us ask fundamentally new questions about how the embryo finds its home within the uterus and what factors are needed for it to implant successfully. Once we can understand how these processes happen normally, we can also ask why certain genetic mutations cause pregnancies to fail, to study the potential dangers of environmental toxins such as the chemicals in common household products, and even why metabolic disease and obesity appears to compromise implantation.”

If you want to see this womb with a view, check out the video below.

Watch these two videos for more information:

Salk scientists reverse signs of aging in mice. For our next scintillating stem cell story, we’re turning back the clock – the aging clock that is. Scientists from the Salk Institute in La Jolla, reported an interesting method in the journal Cell  that reverses some signs of aging in mice. They found that periodic expression of embryonic stem cell genes in skin cells and mice could reverse some signs of aging.

The Salk team made use of cellular reprogramming tools developed by the Nobel Prize winning scientist Shinya Yamanaka. He found that four genes normally expressed in embryonic stem cells could revert adult cells back to a pluripotent stem cell state – a process called cellular reprogramming. Instead of turning adult cells back into stem cells, the Salk scientists asked whether the Yamanaka factors could instead turn back the clock on older, aging cells – making them healthier without turning them back into stem cells or cancer-forming cells.

The team found that they could rejuvenate skin cells from mice without turning them back into stem cells if they turned on the Yamanaka genes on for a short period of time. These skin cells were taken from mice that had progeria – a disease that causes them to age rapidly. Not only did their skin cells look and act younger after the treatment, but when the scientists used a similar technique to turn on the Yamanaka genes in progeria mice, they saw rejuvenating effects in the mice including a more rapid healing and regeneration of muscle and pancreas tissue.

(Left) impaired muscle repair in aged mice; (right) improved muscle regeneration in aged mice subjected to reprogramming. (Salk Institute)

(Left) impaired muscle repair in aged mice; (right) improved muscle regeneration in aged mice subjected to reprogramming. (Salk Institute)

The senior author on the study, Salk Professor Juan Carlos Izpisua Belmonte, acknowledged in a Salk news release that this is early stage work that focuses on animal models, not humans:

“Obviously, mice are not humans and we know it will be much more complex to rejuvenate a person. But this study shows that aging is a very dynamic and plastic process, and therefore will be more amenable to therapeutic interventions than what we previously thought.”

This story was very popular, which is not surprising as aging research is particularly fascinating to people who want to live longer lives. It was covered by many news outlets including STATnews, Scientific American and Science Magazine. I also recommend reading Paul Knoepfler’s journal club-style blog on the study for an objective take on the findings and implications of the study. Lastly, you can learn more about the science of this work by watching the movie below by the Salk.

Movie:

Stabilizing unstable stem cells. Our final stem cell story is brought to you by scientists from the UCLA Broad Stem Cell Research Center. They found that embryonic stem cells can harbor genetic instabilities that can be passed on to their offspring and cause complications, or even disease, later in life. Their work was published in two separate studies in Cell Stem Cell and Cell Reports.

The science behind the genetic instabilities is too complicated to explain in this blog, so I’ll refer you to the UCLA news release for more details. In brief, the UCLA team found a way to reverse the genetic instability in the stem cells such that the mature cells that they developed into turned out healthy.

As for the future impact of this research, “The research team, led by Kathrin Plath, found a way to correct the instability by resetting the stem cells from a later stage of development to an earlier stage of development. This fundamental discovery could have great impact on the creation of healthy tissues to cure disease.”

Translating great stem cell ideas into effective therapies

alzheimers

CIRM funds research trying to solve the Alzheimer’s puzzle

In science, there are a lot of terms that could easily mystify people without a research background; “translational” is not one of them. Translational research simply means to take findings from basic research and advance them into something that is ready to be tested in people in a clinical trial.

Yesterday our Governing Board approved $15 million in funding for four projects as part of our Translational Awards program, giving them the funding and support that we hope will ultimately result in them being tested in people.

Those projects use a variety of different approaches in tackling some very different diseases. For example, researchers at the Gladstone Institutes in San Francisco received $5.9 million to develop a new way to help the more than five million Americans battling Alzheimer’s disease. They want to generate brain cells to replace those damaged by Alzheimer’s, using induced pluripotent stem cells (iPSCs) – an adult cell that has been changed or reprogrammed so that it can then be changed into virtually any other cell in the body.

CIRM’s mission is to accelerate stem cell treatments to patients with unmet medical needs and Alzheimer’s – which has no cure and no effective long-term treatments – clearly represents an unmet medical need.

Another project approved by the Board is run by a team at Children’s Hospital Oakland Research Institute (CHORI). They got almost $4.5 million for their research helping people with sickle cell anemia, an inherited blood disorder that causes intense pain, and can result in strokes and organ damage. Sickle cell affects around 100,000 people in the US, mostly African Americans.

The CHORI team wants to use a new gene-editing tool called CRISPR-Cas9 to develop a method of editing the defective gene that causes Sickle Cell, creating a healthy, sickle-free blood supply for patients.

Right now, the only effective long-term treatment for sickle cell disease is a bone marrow transplant, but that requires a patient to have a matched donor – something that is hard to find. Even with a perfect donor the procedure can be risky, carrying with it potentially life-threatening complications. Using the patient’s own blood stem cells to create a therapy would remove those complications and even make it possible to talk about curing the disease.

While damaged cartilage isn’t life-threatening it does have huge quality of life implications for millions of people. Untreated cartilage damage can, over time lead to the degeneration of the joint, arthritis and chronic pain. Researchers at the University of Southern California (USC) were awarded $2.5 million to develop an off-the-shelf stem cell product that could be used to repair the damage.

The fourth and final award ($2.09 million) went to Ankasa Regenerative Therapeutics, which hopes to create a stem cell therapy for osteonecrosis. This is a painful, progressive disease caused by insufficient blood flow to the bones. Eventually the bones start to rot and die.

As Jonathan Thomas, Chair of the CIRM Board, said in a news release, we are hoping this is just the next step for these programs on their way to helping patients:

“These Translational Awards highlight our goal of creating a pipeline of projects, moving through different stages of research with an ultimate goal of a successful treatment. We are hopeful these projects will be able to use our newly created Stem Cell Center to speed up their progress and pave the way for approval by the FDA for a clinical trial in the next few years.”

Trash talking and creating a stem cell community

imilce2

Imilce Rodriguez-Fernandez likes to talk trash. No, really, she does. In her case it’s cellular trash, the kind that builds up in our cells and has to be removed to ensure the cells don’t become sick.

Imilce was one of several stem cell researchers who took part in a couple of public events over the weekend, on either side of San Francisco Bay, that served to span both a geographical and generational divide and create a common sense of community.

The first event was at the Buck Institute for Research on Aging in Marin County, near San Francisco. It was titled “Stem Cell Celebration” and that’s pretty much what it was. It featured some extraordinary young scientists from the Buck talking about the work they are doing in uncovering some of the connections between aging and chronic diseases, and coming up with solutions to stop or even reverse some of those changes.

One of those scientists was Imilce. She explained that just as it is important for people to get rid of their trash so they can have a clean, healthy home, so it is important for our cells to do the same. Cells that fail to get rid of their protein trash become sick, unhealthy and ultimately stop working.

Imilce is exploring the cellular janitorial services our bodies have developed to deal with trash, and trying to find ways to enhance them so they are more effective, particularly as we age and those janitorial services aren’t as efficient as they were in our youth.

Unlocking the secrets of premature aging

Chris Wiley, another postdoctoral researcher at the Buck, showed that some medications that are used to treat HIV may be life-saving on one level, preventing the onset of full-blown AIDS, but that those benefits come with a cost, namely premature aging. Chris said the impact of aging doesn’t just affect one cell or one part of the body, but ripples out affecting other cells and other parts of the body. By studying the impact those medications have on our bodies he’s hoping to find ways to maintain the benefits of those drugs, but get rid of the downside.

Creating a Community

ssscr

Across the Bay, the U.C. Berkeley Student Society for Stem Cell Research held it’s 4th annual conference and the theme was “Culturing a Stem Cell Community.”

The list of speakers was a Who’s Who of CIRM-funded scientists from U.C. Davis’ Jan Nolta and Paul Knoepfler, to U.C. Irvine’s Henry Klassen and U.C. Berkeley’s David Schaffer. The talks ranged from progress in fighting blindness, to how advances in stem cell gene editing are cause for celebration, and concern.

What struck me most about both meetings was the age divide. At the Buck those presenting were young scientists, millennials; the audience was considerably older, baby boomers. At UC Berkeley it was the reverse; the presenters were experienced scientists of the baby boom generation, and the audience were keen young students representing the next generation of scientists.

Bridging the divide

But regardless of the age differences there was a shared sense of involvement, a feeling that regardless of which side of the audience we are on we all have something in common, we are all part of the stem cell community.

All communities have a story, something that helps bind them together and gives them a sense of common purpose. For the stem cell community there is not one single story, there are many. But while those stories all start from a different place, they end up with a common theme; inspiration, determination and hope.

 

Embryonic gene reverses old age in adult stem cells, in the lab

Getting old is an inevitable fact of life but what exactly causes it? One major hallmark of the aging process is cell senescence, in which cells gradually lose the ability to divide, leading to a breakdown in proper organ function. Adult stem cells that reside in our tissues usually spring into action to replenish cells lost to senescence (as well as injury and disease). But, unfortunately, senescence also affects stem cells, causing their natural regenerative capacity to diminish as we age.

gettingold

During the aging process, our stem cells gradually lose their regenerative potential (image source)

But what if we could tinker with senescence in these elderly stem cells? Could we slow down the aging process? A recent study by University of Buffalo scientists says yes, at least in a petri dish. Reporting in Stem Cells, the team shows that artificially activating the NANOG gene alone can reverse aging in adult mesenchymal stem cells (MSCs) and restore their full potential to form functional muscle tissue.

If you’re up on your induced pluripotent stem (iPS) cell knowledge, then you probably know that NANOG is a member of the “famous four”: the group of genes that can reprogram, say, a skin or blood cell, back into an embryonic stem cell-like state.  In this study, the research team derived human MSCs and mimicked senescence by allowing the cells to divide 12 to 16 times (Late Passage, or LP) in petri dishes and compared them to cells allowed to divide only a few times (Early Passage, or EP). The cells were genetically engineered to produce high levels of NANOG when the drug tetracycline was added to the cell culture.

First, the team looked at the impact of NANOG activation on various genes. They found that the activation level of several genes that had been suppressed in the senescent LP cells was restored to the levels seen in the pre-senescent EP cells. A closer look at the identity of those genes showed they were genes important for the capacity of a cell to develop into muscle and blood vessel which corresponds well with the MSCs potential to specialize into muscle and vascular tissue. Based on that genetic analysis, follow up experiments showed that NANOG indeed restored the senescent LP cells’ potential to develop into muscle and restore the muscle tissue’s contractile function.

Premature senescence is observed in diseases such as Hutchinson–Gilford Progeria Syndrome (HGPS), a fatal genetic disorder that causes rapid aging in childhood. NANOG was artificially activated in human MSCs, derived from a HGPS patient in this study, and also showed a restoration of the MSCs’ potential, as seen in the other donor cells.

In a university press release, lead author Stelios Andreadis, summarized the findings this way:

“Our research into Nanog is helping us to better understand the process of aging and ultimately how to reverse it.”

 

This work is very early days for this research especially given that these studies were performed in lab dishes and not animals. And because NANOG is a powerful gene that promotes embryonic and stem cell identity, the scientists will need to look into potential negative long term side effects for activating NANOG in adult stem cells. Ultimately, this path of research could uncover methods to treat aging-related diseases.

Finally a possible use for your excess fat; using it to fix your arthritic knee

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One of the most common questions we get asked at CIRM, almost every other day to be honest, is “are there any stem cell treatments for people with arthritis in their knees?” It’s not surprising. This is a problem that plagues millions of Americans and is one of the leading causes of disability in the US.

Sadly, we have to tell people that there are no stem cell treatments for osteoarthritis (OA) in the knee that have been approved by the Food and Drug Administration (FDA). There’s also a lack of solid evidence from clinical trials that the various approaches are effective.

But that could be changing. There’s a growing number of clinical trials underway looking at different approaches to treating OA in the knee using various forms of stem cells. Sixteen of those are listed at clinicaltrials.gov. And one new study suggests that just one injection of stem cells may be able to help reduce pain and inflammation in arthritic knees, at least for six months. The operative word here being may.

The study, published in the journal Stem Cells Translational Medicine,  used adipose-derived stromal cells, a kind of stem cell taken from the patient’s own fat. Previous studies have shown that these cells can have immune boosting and anti-scarring properties.

The cells were removed by liposuction, so not only did the patient’s get a boost for their knees they also got a little fat reduction. A nice bonus if desired.

The study was quite small. It involved 18 patients, between the ages of 50 and 75, all of whom had suffered from osteoarthritis (OA) in the knee for at least a year before the treatment. This condition is caused by the cartilage in the knee breaking down, allowing bones to rub against each other, leading to pain, stiffness and swelling.

One group of patients were given a low dose of the cells (23,000) injected directly into the knee, one a medium dose (103,000) and one a high dose (503,000).

Over the next six months, the patients were closely followed to see if there were any side effects and, of course, any improvement in their condition. In a news release, Christian Jorgensen, of University Hospital of Montpellier, the director of the study, said the results were encouraging:

“Although this phase I study included a limited number of patients without a placebo arm we were able to show that this innovative treatment was well tolerated in patients with knee OA and it provided encouraging preliminary evidence of efficacy. Interestingly, patients treated with low-dose ASCs significantly improved in pain and function compared with the baseline.”

The researchers caution that the treatment doesn’t halt the progression of OA and does not restore the damaged cartilage, instead it seems to help patients by reducing inflammation.

In a news article about the study Tony Atala, director of the Wake Forest Institute for Regenerative Medicine, in Winston-Salem, N.C. and the editor of Stem Cells Translational Medicine said the study offered the patients involved another benefit:

“In fact, most of the patients (in the study group) who had previously scheduled total knee replacement surgery decided to cancel the surgery. It will be interesting to see if these improvements are seen in larger groups of study participants.”

Interesting is an understatement.

But while this is encouraging it’s important to remember it was done in a small group of patients and needs to be replicated in a much larger group before we can draw any solid conclusions. It will also be important to see if the benefits last longer than six months.

We might not have to wait too long for some answers. The researchers are already running a 2-year trial involving 150 people in Europe.

We’ll let you know what they find.

 

Stem cell stories that caught our eye: Trifecta of nerve news on aging, Parkinson’s and myelin diseases, also expanding cord blood

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

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Untreated (top) and treated nerves

To save nerves, make them slow down. Nerves, like all cells, constantly make protein, but that task uses up a lot of energy and older nerves have a limited energy supply. A CIRM-funded team at the Salk Institute has shown that an approved drug can slow down protein production in nerves, conserve energy and help them survive.

The Salk team led by Tony Hunter saw the tamping down effect in a disease-in-a-dish model of Leigh syndrome, an inherited neurodegenerative condition caused by a mutation in mitochondria, the cell’s power plant. They created iPS type stem cells by reprogramming skin cells from a Leigh syndrome patient, grew them into nerves and saw evidence of energy depletion that was reversed when they treated the cells with the drug rapamycin.

 “Reducing protein production in ageing neurons allows more energy for the cell to put toward folding proteins correctly and handling stress,” said team member Xinde Zheng, in a Salk release posted by Scicasts. “The impact of our finding is that modulation of protein synthesis could be a general approach to treating neurodegeneration.”

Next step for the team will be seeing if their finding holds true in an animal model of the syndrome. They published their findings in eLife.

 

For dopamine nerves turn them on and off.  Many researchers strive to turn stem cells into dopamine producing nerves to replace the chemical signal that is in short supply in Parkinson’s disease patients. But what if they succeed, put the new nerves in patients and they produce too much dopamine? A team, at the University of Wisconsin has a solution, make the new nerves responsive to a drug that can act as an on-and-off switch.

The team grew nerves from stem cells made from iPS type stem cells and genetically engineered them so that they would only produce dopamine in the presence of a certain drug. Brad Fikes at the San Diego Union Tribune wrote a brief story about the research that the team published in Cell Stem Cell.

 He put the news into perspective by noting that early trials implanting dopamine nerves from fetal tissue resulted in some patients having side effects from over production of the nerve signal transmitter.

 

And restoring nerves protective myelin.  Neurons form the basis of all brain function, but they take a family of support cells and tissues to do a good job of directing our muscles, recording memory, etc.  First nerves need the protective insulation called myelin to properly transmit signals. Cells called oligodendrocytes produce the myelin, but they need signals from cells called astrocytes to do their job well. Researchers have known for some time that immature astrocytes do a great job of fostering oligodendrocytes, but mature astrocytes do not, but they have not known why.

Now, CIRM-funded researchers at the University of California, Davis, have isolated a protein secreted by immature astrocytes called TIMP-1 that promotes proliferation of the needed oligodendrocytes, and down the line, the myelin needed to protect neurons.

In the study published in Cell Reports, the researchers created iPS type stem cells and directed them to become astrocytes, stopping the growth at an immature state and implanted them in mice. But before the transplants, they shut down the production of TIMP-1 in some of the astrocytes, and in those mice they saw no increase in the production of myelin.

 

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Wenbin Deng of UC Davis

The research project leader, Wenbin Deng, speculated in a Davis press release on how the research could eventually help patients with any number of diseases involving myelin loss:

 “We are hopeful that his could lead to a promising therapy for premature brain injury, cerebral palsy, multiple sclerosis, spinal cord injury, white matter stroke and many neurodegenerative diseases.”

 

Key protein for developing blood stem cells.  The stem cells found in umbilical cord have saved thousands of cancer patients by rebuilding their immune system after chemotherapy. But cord blood samples often have too few stem cells to be effective and while a couple teams have reported some progress in expanding the number of stem cells in any one cord sample, more progress is needed.

Researchers at McMaster University reported in the journal Nature this week that they had isolated a protein that controls the development of blood stem cells. That protein, Musashi-2, does not regulate genetic activity at the DNA level, but rather at the next step in the gene-to-protein pathway, regulating the activity of RNA.

In an article posted on the Bioscience Technology website, the team leader Kristin Hope speculated on the value to patients when they learn how to turn this knowledge into making cells for therapy:

“Providing enhanced numbers of stem cells for transplantation could alleviate some of the current post-transplantation complications and allow for faster recoveries, in turn reducing overall health care costs and wait times for newly diagnosed patients seeking treatment.”

 

Scientists tackle aging by stabilizing defective blood stem cells in mice

Aging is an inevitable process that effects every cell, tissue, and organ in your body. You can live longer by maintaining a healthy, active lifestyle, but there is no magic pill that can prevent your body’s natural processes from slowly breaking down and becoming less efficient. As author Chinua Achebe would say, “Things Fall Apart”.

Adult stem cells are an unfortunate victim of the aging process. They have the important job of replenishing the cells in your body throughout your lifetime. However, as you grow older, adult stem cells lose their regenerative ability and fail to maintain the integrity and function of their tissues and organs. This can happen for a number of reasons, but no matter the cause, dysfunctional stem cells can accelerate aging and contribute to a shortened lifespan.

So to put it simply, aging adult stem cells = decline in stem cell function = shortened lifespan.

Dysfunctional blood stem cells make an unhappy immune system

Human blood (red) and immune cells (green) are made from hematopoietic/blood stem cells. Photo credit: ZEISS Microscopy.

Human blood (red) and immune cells (green) are made from hematopoietic/blood stem cells. Photo credit: ZEISS Microscopy.

A good example of this process is hematopoietic stem cells (HSCs), which are adult stem cells found in bone marrow that make all the cells in our blood and immune system. When HSCs get old, they lose their edge and fail to generate some of the important blood cell types that are crucial for a healthy immune system. This can be life-threatening for elderly people who are at higher risk for infections and disease.

So how can we improve the function of aging HSCs to boost the immune system in older people and potentially extend their healthy years of life? A team of researchers from Germany might have an answer. They’ve identified a genetic switch that revitalizes aged, defective HSCs in mice and prolongs their lifespan. They published their findings this week in Nature Cell Biology.

Identifying the Per-petrator for aging HSCs

The perpetrator in this story is a gene called Per2. The team identified Per2 through a genetic screen of hundreds of potential tumor suppressor genes that could potentially impair the regenerative abilities of HSCs in response to DNA damage caused by aging.

It turns out that the Per2 gene is turned on in a subset of HSCs, called lymphoid-HSCs, that preferentially generate blood cells in the lymphatic system. These include B and T cells, both important parts of our immune system. When Per2 is turned on in lymphoid-HSCs, it activates the DNA damage response pathway. While responding to DNA damage may sound like a good thing, it also slows down the cell division process and prevents lymphoid-HSCs from producing their normal amount of lymphoid cells. Adding insult to injury, Per2 also activates the p53-dependent apoptosis pathway, which causes programmed cell death and further reduces the number of HSCs in reserve.

To address these problems, the team decided to delete the Per2 gene in mice and study the function of their HSCs as they aged. They found that removing Per2 stabilized lymphoid-HSCs and rescued their ability to generate the appropriate number of lymphoid cells. Per2 deletion also boosted their immune system, making the mice less susceptible to infection, and extended their lifespan by as much as 15 percent.

A key finding was that deleting Per2 did not increase the incidence of tumors in the aging mice – a logical concern as Per2 mutations in humans are link to increased cancer risk.

Per2 might not be a Per-fect solution for healthy aging

In summary, getting rid of Per2 in the HSCs of older mice improves their function and the function of their immune system while also extending their lifespan.

Senior author on the study, Karl Lenhard Rudolph, commented about their findings in a news release:

Karl Lenhard Rudolph. Photo: Anne Günther/FSU

Karl Lenhard Rudolph.

“All in all, these results are very promising, but equally surprising. We did not expect such a strong connection between switching off a single gene and improving the immune system so clearly.”

 

 

So Per2 may be a good healthy aging target in mice, but the real question is whether these results will translate to humans. Per2 is a circadian rhythm gene and is important for regulating the sleep-wake cycle. Deleting this gene in humans could cause sleep disorders and other unwanted side effects.

Rudolph acknowledges that his team needs to move their focus from mouse to humans.

“It is not yet clear whether this mutation in humans would have a benefit such as improved immune functions in aging — it is of great interest for us to further investigate this question.”