Stem cell stories that caught our eye: organ replacement, ovarian cancer and repairing damaged hearts.

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.

Numbers on organ shortage and review of lab replacements.
Vox, the four-month-old web site, is rapidly becoming a credible news source with more than five million page views so far. With a reputation for explaining the facts behind the news, it was nice to see they tackled the organ shortage and how researchers are using stem cells to try to solve it.

organ shortage.0After providing data on the incredible need, the author addressed several key advances, as well as remaining hurdles, to using stem cells to build replacement organs in the lab. She notes that an important step to growing an organ is being able to grow all the various types of cells that make up a complex organ.

“Each specialized type of cell in your body needs certain chemical clues from its environment in order to thrive and multiply. And even a simple-seeming body part, like a urethra, requires more than one cell type, arranged in certain ways relative to one another.”

In addition to a chart with data on organ donation and need, the article provides a link to a fun video on growing a rat lung in the lab. The author closes with the fact that the greatest need is for kidneys and a discussion of how tough they are to make because of the complex mix of tissues needed.

An advance in building kidneys also made the journals this week, with a press release from Cellular Dynamics describing how their lab grown cells succeeded in coating the inside of blood vessels in a scaffold for a rodent kidney.

Stem cell factors heal damaged hearts. The American Heart Association met in Chicago this week and as always the week of their fall enclave generates several news stories. Genetic Engineering & Biotechnology News wrote up a study from the Icahn School of Medicine at Mount Sinai in New York that suggested how your own stem cells might be recruited to repair damage after a heart attack.

The New York team used a form of gene therapy that introduced the genes for “stem cell factors” that they believe could summon a type of stem cell that some have suggested can repair heart muscle. Although, whether those cells, called c-Kit positive heart stem cells, are actually the cause of the repair remains a subject of debate. They did show that their treatment improved heart function and decreased heart muscle death in the rodent model they were using.

Stem cells improve survival of skin grafts.
With so many soldiers returning from deployments needing reconstructive surgery, several teams at our armed services medical institutes are trying to solve the problem of the soldiers’ immune systems rejecting large skin grafts from donors. One team reported a potentially major advance in the Journal Stem Cells Translational Medicine and the web site benzinga picked up the journal’s press release.

Working in mice the team got the best skin graft survival in animals that received two types of stem cells to induce immune tolerance to the graft. The mice received fat-derived stem cells from humans and an infusion of a small number of their own bone marrow stem cells. The grafts showed no sign of rejection after 200 days, a very long time in a mouse’s life. In the press release, the editor of the journal, Anthony Atala, suggested the results could have broad implications for the field.

“The implications of this research are broad. If these findings are duplicated in additional models and in human trials, there is potential to apply this strategy to many areas of transplantation.”

Leukemia drug may also work in ovarian cancer. The antibody named for CIRM in recognition of our funding of its discovery, cirmtuzumab, which is already in clinical trials in humans for leukemia, may also be effective in one of the most stubborn tumors, ovarian cancer.

Ovarian cancer cells

Ovarian cancer cells

The University of California, San Diego, team led by Thomas Kipps published a study in the Proceedings of the National Academy of Sciences this week showing that in mice the antibody kept transplanted human ovarian cancer cells in check. The tumor that is characterized by rapid spread did not metastasize at all. HealthCanal picked up the university’s press release explaining how the new drug works. You can read about the CIRM-funded clinical trial in leukemia in our fact sheet.

Versatile fingernail stem cells.
The stem cells that regrow our nails are prodigious little critters forcing us to constantly cut or file. But it turns out they are also versatile. They can stimulate nail growth but also growth of skin around the nail.

But if our nails get injured they become single minded and only make nail cells. A team at the University of Southern California has discovered that at the time of injury a particular protein signal gets turned on directing the stem cells to focus on the nails. So, the team is now looking for other signaling proteins that might direct these versatile cells to make other tissues making them potential tools for healing amputations. ScienceDaily picked up the university’s press release.

Don Gibbons

10 Years/10 Therapies: 10 Years after its Founding CIRM will have 10 Therapies Approved for Clinical Trials

In 2004, when 59 percent of California voters approved the creation of CIRM, our state embarked on an unprecedented experiment: providing concentrated funding to a new, promising area of research. The goal: accelerate the process of getting therapies to patients, especially those with unmet medical needs.

Having 10 potential treatments expected to be approved for clinical trials by the end of this year is no small feat. Indeed, it is viewed by many in the industry as a clear acceleration of the normal pace of discovery. Here are our first 10 treatments to be approved for testing in patients.

HIV/AIDS. The company Calimmune is genetically modifying patients’ own blood-forming stem cells so that they can produce immune cells—the ones normally destroyed by the virus—that cannot be infected by the virus. It is hoped this will allow the patients to clear their systems of the virus, effectively curing the disease.

Spinal cord injury patient advocate Katie Sharify is optimistic about the latest clinical trial led by Asterias Biotherapeutics.

Spinal cord injury patient advocate Katie Sharify is optimistic about the clinical trial led by Asterias Biotherapeutics.

Spinal Cord Injury. The company Asterias Biotherapeutics uses cells derived from embryonic stem cells to heal the spinal cord at the site of injury. They mature the stem cells into cells called oligodendrocyte precursor cells that are injected at the site of injury where it is hoped they can repair the insulating layer, called myelin, that normally protects the nerves in the spinal cord.

Heart Disease. The company Capricor is using donor cells derived from heart stem cells to treat patients developing heart failure after a heart attack. In early studies the cells appear to reduce scar tissue, promote blood vessel growth and improve heart function.

Solid Tumors. A team at the University of California, Los Angeles, has developed a drug that seeks out and destroys cancer stem cells, which are considered by many to be the reason cancers resist treatment and recur. It is believed that eliminating the cancer stem cells may lead to long-term cures.

Leukemia. A team at the University of California, San Diego, is using a protein called an antibody to target cancer stem cells. The antibody senses and attaches to a protein on the surface of cancer stem cells. That disables the protein, which slows the growth of the leukemia and makes it more vulnerable to other anti-cancer drugs.

Sickle Cell Anemia. A team at the University of California, Los Angeles, is genetically modifying a patient’s own blood stem cells so they will produce a correct version of hemoglobin, the oxygen carrying protein that is mutated in these patients, which causes an abnormal sickle-like shape to the red blood cells. These misshapen cells lead to dangerous blood clots and debilitating pain The genetically modified stem cells will be given back to the patient to create a new sickle cell-free blood supply.

Solid Tumors. A team at Stanford University is using a molecule known as an antibody to target cancer stem cells. This antibody can recognize a protein the cancer stem cells carry on their cell surface. The cancer cells use that protein to evade the component of our immune system that routinely destroys tumors. By disabling this protein the team hopes to empower the body’s own immune system to attack and destroy the cancer stem cells.

Diabetes. The company Viacyte is growing cells in a permeable pouch that when implanted under the skin can sense blood sugar and produce the levels of insulin needed to eliminate the symptoms of diabetes. They start with embryonic stem cells, mature them part way to becoming pancreas tissues and insert them into the permeable pouch. When transplanted in the patient, the cells fully develop into the cells needed for proper metabolism of sugar and restore it to a healthy level.

HIV/AIDS. A team at The City of Hope is genetically modifying patients’ own blood-forming stem cells so that they can produce immune cells—the ones normally destroyed by the virus—that cannot be infected by the virus. It is hoped this will allow the patients to clear their systems of the virus, effectively curing the disease

Blindness. A team at the University of Southern California is using cells derived from embryonic stem cell and a scaffold to replace cells damaged in Age-related Macular Degeneration (AMD), the leading cause of blindness in the elderly. The therapy starts with embryonic stem cells that have been matured into a type of cell lost in AMD and places them on a single layer synthetic scaffold. This sheet of cells is inserted surgically into the back of the eye to replace the damaged cells that are needed to maintain healthy photoreceptors in the retina.

UCLA team cures infants of often-fatal “bubble baby” disease by inserting gene in their stem cells; sickle cell disease is next target

Poopy diapers, ear-splitting cries, and sleepless nights: sure, the first few weeks of parenthood are grueling but those other moments of cuddling and kissing your little baby are pure bliss.

The bubble boy.  Born in 1971 with SCID, David Vetter lived in a sterile bubble to avoid outside germs that could kill him. He died in 1984 at 12 due to complications from a bone marrow transplant. [Credit: Baylor College of Medicine Archives]

The bubble boy. Born in 1971 with SCID, David Vetter lived in a sterile bubble to avoid outside germs that could kill him. He died in 1984 at 12 due to complications from a bone marrow transplant. [Credit: Baylor College of Medicine Archives]

That wasn’t the case for Alysia and Christian Padilla-Vacarro of Corona, California. Close contact with their infant daughter Evangelina, born in 2012, was off limits. She was diagnosed with a genetic disease that left her with no immune system and no ability to fight off infections so even a minor cold could kill her.

Evangelina was born with Severe Combined Immunodeficiency (SCID) also called “bubble baby” disease, a term coined in the 1970s when the only way to manage the disease was isolating the child in a super clean environment to avoid exposure to germs. Bone marrow transplants from a matched sibling offer a cure but many kids don’t have a match, which makes a transplant very risky. Sadly, many SCID infants die within the first year of life.

Until now, that is.

Today, a UCLA research team led by Donald Kohn, M.D., announced a stunning breakthrough cure that saved Evangelina’s life and all 18 children who have so far participated in the clinical trial. Kohn—the director of UCLA’s Human Gene Medicine Program—described the treatment strategy in a video interview with CIRM (watch the video below):

“We collect some of the baby’s own bone marrow, isolate the [blood] stem cells, add the gene that they’re missing that their immune system needs and then transplant the cells back to them. “

Inserting the missing gene, called ADA, into the blood stem cells restores the cells’ ability to produce a healthy immune system. And since the cells originally came from the infant, there’s no worry about the possible life-threatening complications from receiving non-matched donor cells.

This breakthrough didn’t occur overnight. Kohn and colleagues have been plugging away for over twenty years carrying out trials, observing their limitations and going back to lab to improve the technology. Their dedication has paid off. As Kohn states in a press release:

“All of the children with SCID that I have treated in these stem cell clinical trials would have died in a year or less without this gene therapy, instead they are all thriving with fully functioning immune systems.”

Alysia Padilla-Vacarro and daughter Evangelina on the day of her gene therapy treatment. Evangelina, now two years old, has had her immune system restored and lives a healthy and normal life. [Credit: UCLA Broad Center of Regenerative Medicine and Stem Cell Research.]

Alysia Padilla-Vacarro and daughter Evangelina on the day of her gene therapy treatment. Evangelina, now two years old, has had her immune system restored and lives a healthy and normal life. [Credit: UCLA Broad Center of Regenerative Medicine and Stem Cell Research.]

For the Padilla-Vacarro family, the dark days after Evangelina’s grave diagnosis have given way to a bright future. Alysia, Evangelina’s mom, poignantly recalled her daughter’s initial recovery:

”It was only around six weeks after the procedure when Dr. Kohn told us Evangelina can finally be taken outside. To finally kiss your child on the lips, to hold her, it’s impossible to describe what a gift that is. I gave birth to my daughter, but Dr. Kohn gave my baby life.”

The team’s next step is to get approval by the Food and Drug Administration (FDA) to provide this treatment to all SCID infants missing the ADA gene.

At the same time, Kohn and colleagues are adapting this treatment approach to cure sickle cell disease, a genetic disease that leads to sickle shaped red blood cells. These misshapen cells are prone to clumping causing debilitating pain, risk of stroke, organ damage and a shortened life span. CIRM is providing over $13 million in funding to support the UCLA team’s clinical trial set to start early next year.

For more information about CIRM-funded sickle cell disease research, visit our fact sheet.

Spinal cord injury and stem cell research; find out the latest in a Google Hangout

Spinal cord injuries are devastating, leaving the person injured facing a life time of challenges, and placing a huge strain on their family and loved ones who help care for them.

The numbers affected are not small. More than a quarter of a million Americans are living with spinal cord injuries and there are more than 11,000 new cases each year.

It’s not just a devastating injury, it’s also an expensive one. According to the National Spinal Cord Injury Statistical Center it can cost more than $775,000 to care for a patient in the first year after injury, and the estimated lifetime costs due to spinal cord injury can be as high as $3 million.

Right now there is no cure, and treatment options are very limited. We have heard for several years now about stem cell research aimed at helping people with spinal cord injuries, but where is that research and how close are we to testing the most promising approaches in people?

That’s going to be the focus of a Google Hangout on Spinal Cord Injury and Stem Cell Research that we are hosting tomorrow, Tuesday, November 18 from noon till 1pm PST.

We’ll be looking at the latest stem cell-based treatments for spinal cord injury including work being done by Asterias Biotherapeutics, which was recently given approval by the Food and Drug Administration (FDA) to start a clinical trial for spinal cord injury. We are giving Asterias $14.3 million to carry out that trial and you can read more about that work here.

We’re fortunate in having three great guests for the Hangout: Jane Lebkowski, Ph.D., the President of research and development at Asterias; Roman Reed, a patient advocate and tireless champion of stem cell research and the founder of the Roman Reed Foundation; and Kevin Whittlesey, Ph.D., a CIRM science officer, who will discuss other CIRM-funded research that aims to better understand spinal cord injury and to bring stem cell-based therapies to clinic trials.

You can find out how to join the Hangout by clicking on the event page link: http://bit.ly/1sh1Dsm

The event is free and interactive, so you’ll be able to ask questions of our experts. You don’t need a Google+ account to watch the Hangout – just visit the event page at the specified time. If you do have a G+ account, please RSVP at the event page (link shown above). Also, with the G+ account you can ask questions in the comment box on this event page. Otherwise, you can tweet questions using #AskCIRMSCI or email us at info@cirm.ca.gov.

We look forward to seeing you there!

Stem cell stories that caught our eye: gene editing tools, lung repair in COPD and big brains

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.

Correcting the genetic error in sickle-cell disease might be as simple as editing the text.

Correcting the genetic error in sickle-cell disease might be as simple as editing the text [Credit: Nature News].

Review of the many ways to edit defective genes. Nature’s news section did a nice review of the many ways blood-forming stem cells can be genetically altered to correct diseases caused by a single mutation. If you have been following the recently booming field of gene therapy, you may have a hard time keeping all the items in the gene editing toolbox straight. The Nature author provides a rundown on the leading contenders—viral vectors, zinc fingers, TALENs and CRISPRs. Early in the piece she describes why researchers are so excited by the field.

“Although most existing treatments for genetic diseases typically only target symptoms, genetic manipulation or ‘gene therapy’ goes after the cause itself.”

Much of the article talks about work by CIRM grantees. It describes work by Don Kohn at the University of California, Los Angeles, on vectors and zinc fingers, as well as work by Juan Carlos Izpisua Belmonte at the Salk Institute using TALENS and CRISPRs. We explain Kohn’s work treating sickle cell disease in our Fact Sheet.

Getting lungs to repair themselves. A research team at Jackson Labs in Maine has isolated a stem cell in lungs that appears to be able to repair damage left behind by severe infections. They hope to learn enough about how those stem cells work to enlist them to repair damage in diseases like Chronic Obstructive Pulmonary Disease (COPD).

They published the work in Nature and ScienceDaily picked up the lab’s press release. It quotes the lead researcher, Wa Xian on the hope they see down the road for the 12 million people in the U.S. with COPD:

“These patients have few therapeutic options today. We hope that our research could lead to new ways to help them.”

Making middle-man cells more valuable. The University of Wisconsin lab of Jamie Thomson, where human embryonic stem cells (ESCs) were first isolated, has found a way to make some of the offspring of those stem cells more valuable.

We have often written that for therapy, the desired cell to start with is not an ESC or even the end desired adult tissue, but rather a middleman cell called a progenitor. But those cells often don’t renew, or replicate themselves, very well in the lab. Ideally researchers would like to have a steady supply of progenitor cells that could be pushed to mature further only when needed. The Thomson lab found that by manipulating a few genes they could arrest the development of progenitors so they constantly renew themselves. ScienceNewsline picked up the press release from the University’s Morgridge Institute that houses the Thomson lab.

Link found to human’s big brains. A CIRM-funded team at the University of California, San Francisco, isolated a protein that seems to be responsible for fostering the large brain size in humans compared with other animals. Human brain stem cells need the protein, dubbed PDGFD, to reproduce.

The team found that the protein acts on parts of the brain that have changed during mammalian evolution. It is not active at all in mice brains, for example. So, if someone accuses you of being a smart aleck just tell them you can’t help it, it’s your PDGFD. HealthCanal ran the university’s press release, which provides a lot more detail of how the protein actually helps give us big heads.

Don Gibbons

More Than Meets the Eye: Protein that Keeps Cancer in Check also Plays Direct Role in Stem Cell Biology, a Stanford Study Finds.

Here’s a startling fact: the retinoblastoma protein —Rb, for short — is defective or missing in nearly all cancers.

Rb is called a tumor suppressor because it prevents excessive cell growth by acting as a crucial traffic stop for the cell cycle, a process that controls the timing for a cell to divide and multiply. Without a working Rb protein, that traffic barrier on cell division is effectively removed, allowing unrestricted cell growth and a path towards cancer.

Retinoblastoma - a known road block to cancer growth also inhibits a stem cell's capacity to change into any cell type

Retinoblastoma – a known road block to cancer growth also inhibits a stem cell’s capacity to change into any cell type

The Rb gene was cloned over two decades ago and its link to cancer has been known for years. But today in Cell Stem Cell, CIRM-funded scientists at Stanford University report an unexpected finding: Rb protein also inhibits a stem cell’s pluripotency, or it’s capacity to become any type of cell in the body. Julien Sage, a senior author of the report, described this new facet to Rb in a press release:

“We were very surprised to see that retinoblastoma directly connects control of the cell cycle with pluripotency. This is a completely new idea as to how retinoblastoma functions.”

The research team uncovered Rb’s versatility in experiments using the induced pluripotent stem cell (iPS) technique in which adult cells, such as a skin, are reprogrammed to an embryonic stem cell-like state that, in turn, can be transformed into any cell type.

Creating iPS cells is notoriously slow and inefficient. However, the Stanford scientists found that cells without Rb were much easier and faster to convert to iPS than cells with normal Rb. And when Rb protein levels in the cells were boosted, it was much more difficult to make the iPS cells — suggesting that the presence of Rb was encouraging the skin cells to remain skin and to resist reprogramming into an iPS cell. As Marius Wernig, the other senior author, sums it up:

“The loss of Rb appears to directly change a cell’s identity. Without the protein, the cell is much more developmentally fluid and is easier to reprogram into an iPS cell.”

And Dr. Sage further points out that:

“The process of creating iPS cells from fully differentiated, or specialized, cells is in many ways very similar to what happens when a cell becomes cancerous.”

So now that the team has established the Rb protein’s direct link between stem cell and cancer biology, they stand at unique vantage point to gain new insights on the inner workings of both, such as better iPS methods and new cancer therapy targets.

To hear about more aspects of Marius Wernig’s research, watch his 30 second elevator pitch below:

Creating a Genetic Model for Autism, with a Little Help from the Tooth Fairy

One of the most complex aspects of autism is that it is not one disease—but many. Known more accurately as the autism spectrum disorder, or ASD, experts have long been trying to tease apart the various ways in which the condition manifests in children, with limited success.

But now, using the latest stem cell technology, scientists at the University of California, San Diego (UCSD) have identified a gene associated with Rett Syndrome—a rare form of autism almost exclusively seen in girls. And in so doing, the team has made the startling discovery that the many types of autism may be linked by common molecular pathways.

The research team, led by UCSD Professor and CIRM grantee Alysson Muotri, explained in a news release how induced pluripotent stem cell, or iPS cell, technology was used to pinpoint a gene associated with Rett Syndrome:

“One can take advantage of genomics to map all mutant genes in the patient and then use their own iPS cells to measure the impact of mutations in relevant cell types. Moreover, the study of brain cells derived from these iPS cells can reveal potential therapeutic drugs tailored to the individual. It is the rise of personalized medicine for mental and neurological disorder.”

iPS cell technology—a process by which scientists transform adult skin cells back into embryonic-like stem cells, after which they can be coaxed into maturing into virtually any type of cell—is a promising way to model diseases at the cellular level. But in order to truly understand what is happening in the brains of people with autism, Muotri and his team needed more samples from autistic individuals—on the order of hundreds or even thousands.

The Tooth Fairy Project allows scientists to gather large quantities of cells from autistic individuals for genomic analysis—simply asking parents to send in a discarded baby tooth.

The Tooth Fairy Project allows scientists to gather large quantities of cells from autistic individuals for genomic analysis—simply by asking parents to send in a discarded baby tooth.

Luckily, Muotri had a little help from the Tooth Fairy.

Or, more accurately, the Tooth Fairy Project, in which parents register for a “Fairy Tooth Kit” that lets them send a discarded baby tooth of their autistic child to researchers. Housed within each baby tooth are cells that can be transformed—with iPS cell technology—into neurons, thus giving the researchers a massive sample size with which to study.

Interestingly, the findings presented here come from the very first tooth to be sent to Muotri. Specifically, the team identified a mutation in the gene TRPC6 was present in children with autism. Additional experiments in animal models revealed that the TRPC6 mutation was indeed associated with abnormal brain cell development and function.

And for their next trick, the team found a way to reverse the mutation’s damaging effects.

By treating the cells with the chemical hyperforin, they were able to restore some normal function to the neurons—offering up a potential therapeutic strategy for treating ASD patients who harbor the TRPC6 mutation.

Drilling down even further, the team found that mutations in another gene called MeCP2, which causes Rett Syndrome, also set off a genetic domino effect that alters the normal function of the TRPC6 gene. Thus connecting this syndrome with other, non-syndromic types of autism.

“Taken together, these findings suggest that TRPC6 is a novel predisposing gene for ASD that may act in a multiple-hit model,” said Muotri. “This is the first study to use iPS cell-derived human neurons to model non-syndromic ASD and illustrate the potential of modeling genetically complex sporadic diseases using such cells.”

Find out more about how stem cell research could help solve the mysteries behind autism in our Autism Fact Sheet.

CIRM Scientists Discover Key to Blood Cells’ Building Blocks

Our bodies generate new blood cells—both red and white blood cells—each and every day. But reproducing that feat in a petri dish has proven far more difficult.

Pictured: sections from zebrafish embryos. Blood vessels are labeled in red, the protein complex that regulates inflammation green and cell nuclei in blue. The arrowhead indicates a potential HSC. The image at bottom right combines all channels. [Credit: UC San Diego School of Medicine]

Pictured: sections from zebrafish embryos. Blood vessels are labeled in red, the protein complex that regulates inflammation green and cell nuclei in blue. The arrowhead indicates a potential HSC. The image at bottom right combines all channels.
[Credit: UC San Diego School of Medicine]

But now, scientists have identified the missing ingredient to producing hematopoietic stem cells, or HSC’s—the type of stem cell that gives rise to all blood and immune cells in the body. The results, published last week in the journal Cell, describe how a newly discovered protein plays a key role in generating HSC’s in the developing embryo—giving scientists a more complete recipe to reproduce these cells in the lab.

The research, which was led by University of California, San Diego (UCSD) professor David Traver and supported by a grant from CIRM, offers renewed hope for the possibility of generating patient-specific blood or immune cells using induced pluripotent stem cell (iPS cell) technology.

As Traver explained in last week’s news release:

“The development of some mature cell lineages from iPS cells, such as cardiac or neural, has been reasonably straightforward, but not with HSCs. This is likely due, at least in part, to not fully understanding all the factors used by the embryo to generate HSCs.”

Indeed, the ability to generate HSCs has long challenged scientists, as outlined in a CIRM workshop from last year. But now, says Traver, they have found a crucial piece to the puzzle.

Specifically, the researchers investigated a signaling protein called tumor necrosis factor alpha—or TNFα for short— a protein known to be important for regulating inflammation and immunity. Previous research by this study’s first author, Raquel Espin-Palazon, and others also discovered it was related to the healthy function of blood vessels during embryonic development.

In this study, Traver, Espin-Palazon and the UCSD drilled down even further—and found that TNFα was required for the normal development of HSCs in the embryo. This surprised the research team, as the young embryo is generally considered to be sterile—with no need for a protein normally charged with regulating immune response to be switched on. Explained Traver:

“There was no expectation that pro-inflammatory signaling would be active at this time or in the blood-forming regions.”

While preliminary, establishing this relationship between TNFα and HSC formation will be a boon to researchers looking for new ways to generate large quantities of healthy, patient-specific red and white blood cells for those patients who so desperately need them.

Learn more about how stem cell technology could help treat blood diseases in our Thalassemia Fact Sheet.

Stem cell stories that caught our eye: heart repair, epilepsy and comparing cloned and reprogrammed 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.

Reminding broken hearts how to mend them selves.
After years of tracking down the right genetic buttons a team at the Salk Institute in La Jolla has taught a mammal to do what zebra fish do naturally, repair a severely damaged heart. While all our cells have the genetic code for building whole organs those genes seem to be switched off in all higher animals, but active in some more primitive species like zebra fish and salamanders.

New cells (red) repairing injury in a zebra fish heart.

New cells (red) repairing injury in a zebra fish heart.

Starting a decade ago the researchers measured the gene activity during heart repair in the fish. They found many genes that had their on-off status change during repair. They then looked to see which of those genes had been preserved during evolution to mammal species. They found four genes that were turned off during repair in the fish but were turned on in the mice they were using.

When, with CIRM funding, they inserted genetic signals to turn off those genes in the mice, they saw significant repair of the damaged heart. There are many steps between this advance and getting human hearts to repair them selves—notably finding a way to introduce the genetic signals without using the virus used in this study. HealthCanal picked up the institute’s press release.

Cloned stem cells pretty much like reprogrammed stem cells. In the early days of stem cell research there was a great deal of excitement about the possibility of creating stem cells that genetically match a patient by a process commonly called cloning. This process of taking the genetic storehouse of a cell, the nucleus, and inserting it into a donor egg had been relatively easy in mice. But it turned out quite difficult in humans and was only accomplished last year.

During the years of failed attempts at this process known as nuclear transfer in humans an alternative came into the field. The Nobel prize-winning discovery that you can reprogram any adult cell to act like an embryonic stem cell gave us a new way to create personalized stem cells that genetically match a patient. But ever since that 2008 advance, the research community has fretted over whether those new stem cells called iPS cells really match embryonic stem cells. The iPS cells came from older cells that had lived through many opportunities for mutation and the genetic factors used to reprogram them added further opportunities for mutation.

Researchers at the New York Stem Cell Foundation’s in house lab have now compared the two types of cells with several layers of genetic analysis. They found the same level of mutation in the iPS cells and the cells from nuclear transfer lending some reassurance to the use of iPS cells going forward. HealthCanal ran the foundation’s press release.

A more efficient way to make cloned stem cells. Even though a team in Oregon overcame the obstacles to creating stem cells by nuclear transfer last year, and the feat has been repeated by the New York team above and others, it remains terribly inefficient. So, several groups are working on better ways to make these potentially valuable cells.

A former colleague now at Children’s Hospital, Boston wrote a nice explanation of how researchers are going about making these cloned cells easier in the hospital’s blog, Vector.

Stem cells reduced seizures.
The seizures endured by people with many forms of epilepsy originate from genetic defects in their nerves. So, a team at McClean Hospital outside of Boston implanted healthy nerves grown from embryonic stem cells in mice with genetically linked seizures. Half the mice no longer had seizures and the other half had their seizure frequency reduced.

The type of nerves transplanted are called interneurons, which are known to be the nerves that reduce firing of signals. In epilepsy nerve signals are hyperactive. The team is now working on methods to mature the stem cells into purer populations of just the desired interneurons. ClinicalSpace picked up the hospital’s press release.

Don Gibbons

Unlocking the Wonder Drug’s Secrets: Aspirin Fends Off Colon Cancer by Killing Faulty Intestinal Stem Cells

Over 700,000 people worldwide died from colorectal cancer in 2010, up from 500,000 in 1990, making it the fourth leading cause of cancer death behind lung, stomach and liver.

Remarkably, your household bottle of aspirin – in addition to relieving the common headache – protects against colorectal cancer based on several clinical trials over the past few decades. Though its effect is clear, how exactly aspirin prevents colon cancer has remained murky.

Who cares how it works as long as it saves lives, right?

Ball and stick model of aspirin, the wonder drug: relieves pain and prevents cancer

Ball and stick model of the wonder drug, aspirin. It not only relieves pain but also prevents heart attacks and even cancer.

Well, it turns out that long-term daily use of aspirin carries risks of internal bleeding of the stomach and brain, kidney failure, and certain types of strokes. So unraveling what exactly aspirin does to fend off tumors is an important step to finding new drugs with fewer side effects.

Earlier this week, scientists at University of Pittsburgh Cancer Institute (UPCI) reported that they’ve unlocked the secrets of aspirin’s tumor-killing powers. In their study, published in the Proceedings of the National Academy of Sciences (PNAS), the UPCI team shows that aspirin prevents colon cancer by orchestrating the death of stem cells in the intestine that carry a dangerous mutation.

Most colorectal cancers initially crop up with a mutation in a gene called APC. The APC protein is a so-called tumor suppressor, which acts to keep a lid on any uncontrolled cell division, an early step to tumor growth. So a bad APC gene leads to a faulty APC protein and, in turn, the potential for normal intestinal cells to become cancerous. The intestine has a rich source of stem cells, which are particularly vulnerable to this mutation since stem cells already possess the ability for unlimited cell growth.

The research team compared colorectal tumor samples from patients who had taken aspirin to those who had not. Using these samples in animal studies, the researchers showed that aspirin triggers cell suicide in intestinal stem cells that carry the APC mutation, effectively killing off the cells with the potential of feeding tumor growth. Healthy intestinal cells, on the other hand, are left unscathed by aspirin.

With this important discovery of cell suicide, or programmed cell death in scientific jargon, as the instigator of aspirin’s ability to prevent colon cancer, the research team finds themselves at an exciting new starting line to find drugs for cancer patients with less harmful side effects.

As the senior author Lin Zhang states in a university press release:

“We want to use our new understanding of this mechanism as a starting point to design better drugs and effective cancer prevention strategies for those at high risk of colon cancer.”