Hed: Stem cell stories that caught our eye: the why’s of heart failure, harnessing stem cells’ repair kits and growing organs

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.

Stem cell model sheds light on heat failure. Pretty much everyone who has heart failure due to cardiomyopathy—where the heart muscle doesn’t work as effectively as it should—or has a condition that could lead there, is taking a beta blocker. The beta-andrenergic pathway, a key molecular pathway in the heart, dysfunctions in patients with cardiomyopathy and we have never known exactly why. We just know these drugs help.

Now, a team at Stanford led by Joseph Wu has used skin samples from patients and normal subjects to create reprogrammed iPS type stem cells, grown them into heart muscle, and compared them at a very fine-tuned molecular level.

Some patients have a mutation in a protein called TNNT2 in heart muscle fibers, which regulates muscle contraction. So, one thing they looked at was the impact of that mutation. Wu’s team followed the actions triggered by this mutation and found they lead to the beta-andrenergic pathway. Wu explained the value he sees in this fundamental understanding of the disease in a Stanford press release:

“As a cardiologist, I feel this basic research study is very clinically relevant. The beta-andrenergic pathway is a major pharmaceutical target for many cardiac conditions. This study confirms that iPS-cell-derived cardiomyocytes can help us understand biologically important pathways at a molecular level, which can aid in drug screening.”

CIRM did not fund this project but we do fund other projects in Wu’s lab including one to advance the use of iPS cells as models of heart disease, one using tissue engineering to repair damaged areas of the heart and one using embryonic stem cells to generate new heart muscle.

Harnessing stem cells’ repair kits. Stem cells repair tissue in multiple ways, but primarily by maturing into cells that replace damaged ones or by excreting various chemicals that give marching orders to neighboring cells to get busy and make the repairs. Those chemicals, collectively called paracrine factors, get excreted by the stem cells in vessels known as exosomes. So, a team at Temple University in Philadelphia decided to try injecting just the exosomes, rather than whole stem cells to repair heart damage. It seemed to work pretty well in mice.

Stem cells release exosomes, tiny vessels that act as repair kits.

Stem cells release exosomes, tiny vessels that act as repair kits.


After treatment with the exosomes, mice with induced heart attacks showed fewer heart cells dying, less scar tissue, more development of new blood vessels and a stronger heart function. The head of the Temple team, Raj Kishore, described the result in a university press release distributed by EuekaAlert:

“You can robustly increase the heart’s ability to repair itself without using the stem cells themselves. Our work shows a unique way to regenerate the heart using secreted vesicles from embryonic stem cells.”

The team went on to isolate a specific regulatory chemical that was among the most abundant in the exosomes. That compound, a type of RNA, produced much of the same results when administered by itself to the mice—intriguing results for further study.

Good primer on using stem cells to grow organs. The Wisconsin State Journal ran a nice primer in both video and prose about what would theoretically go into building a replacement organ from stem cells and some of the basic stem cell principals involved. The piece is part of a series the paper produces with the Morgridge Institute at the University of Wisconsin. This one features an interview with Michael Treiman of Epic Systems:

“The biggest challenge right now is that we can push a stem cell to be a particular type of cell, but in a tissue there’s multiple cells. And an organ like your heart or brain isn’t just made of one cell type; it’s made of many cell types working together.”

Stem cell stories that caught our eye: Spinal cord injury, secret of creating complex tissue, mini brains in a dish and funding

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.

Monkey trial provides some hope for spinal cord injury. Stem cell treatments have made many mice and rats walk again after spinal cord injury, but moving from those rodents to human has been a slow process. Their immune systems and nervous systems are very different from ours. So, it was good to read this week that a team at Japan’s Keio University reported success in monkeys with systems much more like ours.

The experiment was “controlled.” They compared treated and non-treated animals and saw a significant difference in mobility between the two groups. Bloomberg picked up the release from the journal that published the work Stem Cells Translational Medicine, which quoted the study author Hideyuki Okano:

“An animal in the control group, for example, could not raise her hands up to head height at 12 weeks after injury when motor function almost plateaus. On the other hand, at the same point in time a transplanted animal was able to jump successfully and run so fast it was difficult for us to catch her. She could also grip a pen at 3 cm. above head-height.”

But the work requires some caveats. They treated all animals at exactly 14-days post injury, a window considered optimal for having initial inflammation subside and scar tissue not yet formed. Also, the researchers inflicted bruises not more severe damage to the spinal cord. Most patients with spinal cord injury are chronic, long past the 14-day window, and have damage to their spinal cords more severe than these animals.

The researchers started with embryonic stem cells and matured them into nerve progenitor cells, which they injected into the monkeys. While this process can yield plentiful cells for therapy the researchers acknowledged that much more research is needed before they can help the vast majority of spinal cord injuries with more severe and older injuries. CIRM funds a clinical trial using cells derived from embryonic stem cells to treat more complex spinal injuries, but it is just getting underway.

Clues to creating complex tissues. These days getting stem cells to form a single type of tissue, nerve or skin for example, is almost routine, with the remaining hurdle being purity. But getting stem cells to form complex tissues with multiple types of cells, while done a few times, still gets folks attention. For the most part, this is because we don’t know the cell-to-cell interactions required to form complex tissues. A CIRM-funded team at the University of California, San Diego, thinks they have part of the answer.

They studied something called the neurovascular unit, made up of blood vessels, smooth muscle and nerves that regulate heart rate, blood flow and breathing, among other basic functions. Using a lab model they showed how the different cell types come together to form the vital regulatory tissue. San Diego Newscape posted a piece on the work, quoting the study’s senor author David Cheresh:

“This new model allows us to follow the fate of distinct cell types during development, as they work cooperatively, in a way that we can’t in intact embryos, individual cell lines or mouse models. And if we’re ever going to use stem cells to develop new organ systems, we need to know how different cell types come together to form complex and functional structures such as the neurovascular unit.”

And a brainy example.   Prior research has created small brain “organoids” that started with stem cells and self assembled in a lab dish to create layers of nerves and support cells, but the cells did not interact much like normal brain tissue. Now, a team at Stanford has developed “cortex-like spheroids” with different types of cells that talk to each other.

Nerves and supporting cells form layers and organize like in the developing brain

Nerves and supporting cells form layers and organize like in the developing brain

In the new cortex spheres the nerves are healthier with a better network of the natural supporting cells called glial cells. The cells form layers that interact with each other like in our brains as we are developing.

A program at the National Institutes of Health (NIH) focusing on using stem cells to create models of disease in the lab funded the work. Thomas Insel, Director of the NIH’s National Institute of Mental Health described the importance of the current work in a press release from the institute picked up by HealthCanal:

 

“There’s been amazing progress in this field over the past few years. The cortex spheroids grow to a state in which they express functional connectivity, allowing for modeling and understanding of mental illnesses. They do not even begin to approach the complexity of a whole human brain. But that is not exactly what we need to study disorders of brain circuitry.“

The release starts with a fun lede imagining the day when a patient tormented by mental illness could have a model of their disease grown in a dish and researchers could genetically engineer better brain circuits for the patient. Certainly not just around the corner, but not far fetched.

States economic gain from funding research. The very niched web cite Governing posted a piece that appears to be largely from a conference in Washington D.C. hosted by the Greater Phoenix Economic Council. It quotes several experts speaking about the opportunity for states to gain economic advantage by funding research.

The piece notes some well documented examples of federal government spending on research spawning industries—think Silicon Valley. Then it talks about some more recent state examples including the California initiative that created CIRM.

One speaker, Mark Muro of the Brookings Institute said that we are in a new era now and states may not be able to fund research through their general tax revenue. He said:

“It may be the state becoming part of a consortium or working with Fortune 500 companies, or going to voters with a general obligation bond vote. I think we’re heading for a new complexity.”

Since CIRM was created through a vote for bonds, guess we have to agree.

Stem cell stories that caught our eye: iPS cells guide ALS trial, genetic link to hearing loss and easier to use stem cell

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.

An ALS clinical trial with a twist.
It is well known that the disease we call ALS, or Lou Gehrig’s Disease, behaves differently in different people, so it makes sense that a potential medication might help some people more than others. Now a collaborative group in the North East wants to use iPS-type stem cells to predict who will respond to a medication at the outset of a clinical trial.

The drug to be tested is already used to calm hyper excitable nerves in people with epilepsy. Hyper excitable nerves also seem to play a role in ALS, at least in some patients. So the team, lead by a researcher at Massachusetts General Hospital with others from Harvard, the Northeast ALS Consortium and GlaxoSmithKline, will reprogram the patients’ blood cells to be iPS type stem cells and grow them into nerve cells in the lab and test their response to the drug, Retigabine.

The ALS Association is providing part of the funding for the effort, and the association’s chief scientist, Lucie Bruijn noted the unique nature of this effort in the association’s press release picked up by Bloomberg.

“This powerful collaboration of leaders in the fields of stem cells, clinical neurology, ALS research and GSK will be the first time that lab data from patient derived stem cells with disease-specific properties that respond to drugs have formed the basis for a clinical trial.”

Do stem cells prefer wearing a coat? One of our grantees and the editor of the journal Stem Cells, Jan Nolta, likes to refer to mesenchymal stem cells as little ambulances that run around the body delivering first aid supplies. These cells found in bone marrow and fat are being tested in many different disease, but in most cases they are not expected to actually make repairs themselves. Instead researchers use them to deliver a variety of protein factors that trigger various components of the body’s natural healing machinery.

Mesenchymal stem cells captured in microcapsules

Mesenchymal stem cells captured in microcapsules

One problem is the cells often do not stick around very long delivering their needed medical supplies. A team at Cornell University in New York thinks they may have found a way to improve the performance of these stem cells, by giving them a coat. By enclosing the stem cells in a capsule the cells stay in place better and more effectively help wounds heal, at least in the lab model the team used.

The university’s press release was picked up by Medical Design Technology.

Noise plus bad genes bad for hearing. Some people can spend years of Saturday nights attending loud rock concerts and have no issue with their hearing. Others end up constantly adjusting the battery on their hearing aids. A CIRM-funded team at the University of Southern California thinks they have fingered a genetic explanation for the difference.

Hearing is a complex process involving many components, which has resulted in no clear answers from previous attempts to find genetic links to hearing loss. The USC team performed a more complex analysis known as a GWAS, genome-wide association study. The result provided strong evidence that variations in the gene Nox3, which is normally turned on only in the inner ear, account for the differences in susceptibility.

Researchers now have a clear target to look for opportunities for prevention and therapy. Futurity picked up the University’s press release.

Accident creates new type of stem cell.
Much of the work with embryonic stem cells centers on figuring out what proteins and other factors to expose them to in order to get them to mature into a desired type of cell. One such attempt at the University of Missouri resulted in creating a new type of stem cell that may be easier to work with than embryonic stem cells (ESCs).

They call their new cells BMP-primed stem cells because one of the various factors they were adding to their ESCs in a lab dish was Bone Morphogenetic Protein. Michael Roberts, the leader of the team, described the potential value of the new stem cells in an article in Genetic Engineering & Biotechnology News:

“These new cells, which we call BMP-primed stem cells, are much more robust and easily manipulated than standard embryonic stem cells. BMP-primed cells represent a transitional stage of development between embryonic stem cells and their ultimate developmental fate, whether that is placenta cells, or skin cells or brain cells.”

For hardcore biologyphiles, the new cells offer a chance to better understand the early stages of embryo development. ESCs can form any part of the body but they cannot form the placenta and other early tissues needed to support the embryo. The BMP-primed stem cells can. So they may yield some long-sought answers about what determines cell fate in the early days after fertilization and perhaps some practical information on diseases related to the placenta like pre-eclampsia.

Stem Cell Scientists Reconstruct Disease in a Dish; Gain Insight into Deadly Form of Bone Cancer

The life of someone with Li-Fraumeni Syndrome (LFS) is not a pleasant one. A rare genetic disorder that usually runs in families, this syndrome is characterized by heightened risk of developing cancer—multiple types of cancer—at a very young age.

People with LFS, as the syndrome is often called, are especially susceptible to osteosarcoma, a form of bone cancer that most often affects children. Despite numerous research advances, survival rates for this type of cancer have not improved in over 40 years.

shutterstock_142552177 But according to new research from Mount Sinai Hospital and School of Medicine, the prognosis for these patients may not be so dire in a few years.

Reporting today in the journal Cell, researchers describe how they used a revolutionary type of stem cell technology to recreate LFS in a dish and, in so doing, have uncovered the series of molecular triggers that cause people with LFS to have such high incidence of osteosarcoma.

The scientists, led by senior author Ihor Lemischka, utilized induced pluripotent stem cells, or iPSCs, to model LFS—and osteosarcoma—at the cellular level.

Discovered in 2006 by Japanese scientist Shinya Yamanaka, iPSC technology allows scientists to reprogram adult skin cells into embryonic-like stem cells, which can then be turned into virtually any cell in the body. In the case of a genetic disorder, such as LFS, scientists can transform skin cells from someone with the disorder into bone cells and grow them in the lab. These cells will then have the same genetic makeup as that of the original patient, thus creating a ‘disease in a dish.’ We have written often about these models being used for various diseases, particularly neurological ones, but not cancer.

“Our study is among the first to use induced pluripotent stem cells as the foundation of a model for cancer,” said lead author and Mount Sinai postdoctoral fellow Dung-Fang Lee in today’s press release.

The team’s research centered on the protein p53. P53 normally acts as a tumor suppressor, keeping cell divisions in check so as not to divide out of control and morph into early-stage tumors. Previous research had revealed that 70% of people with LFS have a specific mutation in the gene that encodes p53. Using this knowledge and with the help of the iPSC technology, the team shed much-needed light on a molecular link between LFS and bone cancer. According to Lee:

“This model, when combined with a rare genetic disease, revealed for the first time how a protein known to prevent tumor growth in most cases, p53, may instead drive bone cancer when genetic changes cause too much of it to be made in the wrong place.”

Specifically, the team discovered that the ultimate culprit of LFS bone cancer is an overactive p53 gene. Too much p53, it turns out, reduces the amount of another gene, called H19. This then leads to a decrease in the protein decorin. Decorin normally acts to help stem cells mature into healthy, bone-making cells, known as osteoblasts. Without it, the stem cells can’t mature. They instead divide over and over again, out of control, and ultimately cause the growth of dangerous tumors.

But those out of control cells can become a target for therapy, say researchers. In fact, the team found that artificially boosting H19 levels could have a positive effect.

“Our experiments showed that restoring H19 expression hindered by too much p53 restored “protective differentiation” of osteoblasts to counter events of tumor growth early on in bone cancer,” said Lemischka.

And, because mutations in p53 have been linked to other forms of bone cancer, the team is optimistic that these preliminary results will be able to guide treatment for bone cancer patients—whether they have LFS or not. Added Lemischka:

“The work has implications for the future treatment or prevention of LFS-associated osteosarcoma, and possibly for all forms of bone cancer driven by p53 mutations, with H19 and p53 established now as potential targets for future drugs.”

Learn more about how scientists are using stem cell technology to model disease in a dish in our special video series: Stem Cells In Your Face:

Stem cell stories that caught our eye; converting bad fat to good, Parkinson’s and X-linked disease

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.

Which fat for you, white, brown or beige.
Those who read up on those pesky fat cells that accumulate in our bodies probably have heard about white fat and brown fat. White is the bad guy linked to obesity and diabetes and brown is the good guy that burns energy and fosters leanness. Add one more color. A team at the University of California, San Francisco, has isolated beige fat that can convert white to brown.

body fatThey now want to see if they can figure out the molecular mechanism behind this conversion to see if they can develop a therapy to combat obesity. I heard a presentation on similar work at the International Society for Stem Cell Research last June, and there were suggestions that the stem cell known to reside in fat may play a role, but no one seems to be sure.

The current research made it into Nature Medicine and ScienceDaily picked up the university’s press release, which quotes the senior researcher, Shingo Kajimura:

“This finding brings us another step closer to the goal of our laboratory, which is engineering fat cells to fight obesity. We are trying to learn how to convert white fat into brown fat, and until now, it had not been demonstrated that this recruitable form of brown fat is actually present in humans.”


A wonkish revelation on reprogrammed stem cells.
When Shinya Yamanaka first discovered how to reprogram adult cells into embryonic-like stem cells, the resulting iPS cells won him the Nobel Prize. But neither he nor anyone else knew exactly how this reprogramming actually happened. It was assumed that by adding genes that are normally only active during embryo development we were turning back the clock and letting the cells sort of start over.

Now, CIRM-funded researchers at Stanford have discovered the cells first go through a clearly identifiable intermediate state that does not have any of the markers of early stem cells, so called pluripotency genes. The leader of the team, Marius Wernig, described his surprise in a university press release picked up by HealthCanal:

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

The research, published in Nature, used a clever new technique that lets cells grow in individual tiny wells on a laboratory plate. Wernig hopes the finding will help his group and others find ways to improve reprogramming efficiency, which is commonly in single percentage points and rarely in the teens.

Chemical trick yields nerves needed in Parkinson’s.
It’s relatively easy to get stem cells to mature into nerves, but can be quite difficult sometimes to get them to grow into just the right kind of nerves. The dopamine-producing nerves needed in Parkinson’s disease turn out to be one of the difficult ones.

Now, a team from Brazil has used an approved drug to treat stem cells in the lab and get them to consistently mature into dopamine-producing nerves. What’s better, the cells survived and continued to produce dopamine for 15 months after being transplanted into mice. ScienceDaily picked up the press release from D’Or Institute for Research and Education.

The X chromosome and disease? Researchers have long sought answers to why when a disease gene resides on the X chromosome, it often causes more harm in boys than girls. A likely culprit is the process a developing embryo uses to shut down one of the two X chromosomes in females, and a team at Stanford thinks they have found a way to discover how.

The CIRM-funded team lead by Howard Chang used a new molecular tool to study in detail all the components of the cell involved in silencing one of the X chromosomes.

Calico cats are female due to X-chromosome silencing.

Calico cats are female due to X-chromosome silencing.

Researchers have known for some time that one particular genetic component, an RNA called Xist, plays a lead role. But Chang’s team discovered 80 different proteins it interacts with in order to completely shut down one X chromosome. They hope that learning more about the process will let researchers figure out how this selective silencing protects females from some of the mutations on the X chromosome.

The Stanford press release, picked up by HealthCanal, starts with a fun explanation of X silencing and how it can lead to calico female cats, but not males—sorry Garfield you don’t exist.

Stem cell stories that caught our eye; cystic fibrosis, brain repair and Type 2 diabetes

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.

“Organoids” screen for cystic fibrosis drugs
. Starting with iPS-type stem cells made by reprogramming skin cells from cystic fibrosis (CF) patients a team at the University of Cambridge in the U.K. created mini lungs in a dish. These organoids should provide a great tool for screening drugs to treat the disease.

The researchers pushed the stem cells to go through the early stages of embryo development and then on to become 3-D distal airway tissue, the part of the lung that processes gas exchange. They were able to use a florescent marker to show an aspect of the cells’ function that was different in cells from CF patients and those from normal individuals. When they treated the CF cells with a drug that is being tested in CF patients, they saw the function correct to the normal state.

Bioscience Technology
picked up the university’s press release about the work published in the journal Stem Cells and Development. It quotes the scientist who led the study, Nick Hannon, on the application of the new tool:

“We’re confident this process could be scaled up to enable us to screen tens of thousands of compounds and develop mini-lungs with other diseases such as lung cancer and idiopathic pulmonary fibrosis.”

To repair a brain knock its “pinky” down. A team at the University of California, San Francisco, has discovered a molecule that when it is shut down nerve stem cells can produce a whole lot more nerves. They call the molecule Pnky, named after the cartoon Pinky and the Brain.

Pinky_and_the_Brain_vol1Pkny belongs to a set of molecules known as long noncoding RNAs (lncRNAs), which researchers are finding are more abundant and more important than originally thought. The most familiar RNAs are the intermediary molecules between the DNA in our genes and the proteins that let our cells function. Initially, all the noncoding RNAs were thought to have no function, but in recent years many have been found to have critical roles in determining which genes are active. And Pnky seems to tamp down the activity of nerve stem cells. In a university press release picked up by HealthCanal Daniel Lim, the head researcher explained what happens when they shut down the gene:

“It is remarkable that when you take Pnky away, the stem cells produce many more neurons. These findings suggest that Pnky, and perhaps lncRNAs in general, could eventually have important applications in regenerative medicine and cancer treatment.”

Lim went onto explain the cancer connection. Since Pnky binds to a protein found in brain tumors, it might be involved in regulating the growth of brain tumors. A lot more work needs to happen before that hunch—or the use of Pnky blockers in brain injury—can lead to therapies, but this study certainly paints an intriguing path forward.

Stem cells and Type 2 diabetes. A few teams have succeeded in using stem cells to produce insulin-secreting tissue to correct Type 1 diabetes in animals, but it has been uncertain if the procedure would work for Type 2 diabetes. Type 1 is marked by a lack of insulin production, while resistance to the body’s own insulin, not lack of insulin, is the hallmark of type 2. A team at the University of British Columbia has new data showing stem cell therapy may indeed have a place in treating Type 2.

In mice fed a high fat diet until they developed the symptoms of Type 2 diabetes the stem cell-derived cells did help, but they did not fully correct the metabolism of the mice until they added one of the drugs commonly used to treat diabetes today. The drugs alone, also did not restore normal metabolism, which is often the case with human Type 2 diabetics.

The combination of drugs and cells improved the mice’s sugar metabolism, body weight and insulin sensitivity. The research appeared in the journal Stem Cell Reports and the University’s press release was picked up by several outlets including Fox News.

They transplanted cells from humans and even though the mice were immune suppressed, they took the added measure of protecting the cells in an encapsulation device. They noted that this would be required for use in humans and showing that it worked in mice would speed up any human trials. They also gave a shout out to the clinical trial CIRM funds at Viacyte, noting that since the Food and Drug Administration has already approved use of a similar device by Viacyte, the work might gain more rapid approval.

Stem cell stories that caught our eye; drug screening, aging stem cells in brain repair and blood diseases

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.

Heart-on-a-chip used to screen drugs. With CIRM funding, a team at the University of California, Berkeley, has used stem cell technology to create a virtual heart on an inch-long piece of silicon. The cells in that “chip” mimic the physiology of a human heart and have shown that they can accurately show how drugs will impact the heart.
HeartChip4196107801
Starting with iPS-type stem cells made from reprogramming adult cells the researchers grew them into heart muscle that could beat and align in multiple layers with microscopic channels that mimic blood vessels. They tested three drugs currently used to treat heart disease and found the changes seen in the heart-on-a-chip were consistent with what is seen in patients. For example, they tested isoproterenol, a drug used to treat slow heart rate and saw a dramatic increase in heart rate.

But the real value in the silicon-housed heart will be in screening potential new drugs and finding out adverse impacts before taking them into costly human clinical trials. Genetic Engineering & Biotechnology News wrote up the work and quoted a member of the team, Kevin Healy:

“It takes about $5 billion on average to develop a drug, and 60 percent of that figure comes from upfront costs in the research and development phase. Using a well-designed model of a human organ could significantly cut the cost and time of bringing a new drug to market.”

Brain stem cell activity decreases with age. We have known for some time that the adult stem cells that reside in most of our tissues and spend our lives repairing those tissues are less effective as we age. But the stemness of those cells—their ability to regenerate themselves—has not generally been questioned, rather we have assumed they just lost some of their ability to mature into the type of cell needed to make the repair.

Now, a team at the Ludwig-Maximilians-Universitat in Munich has published data suggesting that brain stem cells over time loose both their ability to renew themselves and some of their ability to become certain kinds of nerves. ScienceDaily picked up a press release from the institution and it quoted one of the authors, Magdalena Gotz, on the implications of their finding for therapy.

“In light of the fact that the stem cell supply is limited, we must now also look for ways to promote the self-renewal rate of the stem cells themselves and maintain the supply for a longer time.”

Another alternative for correcting genetic blood disease. CIRM funds a few programs that are trying to treat blood diseases such as sickle cell anemia and beta thalassemia by genetically altering blood forming stem cells. The goal being to correct defects in the gene for hemoglobin, the protein that carries oxygen in red blood cells.

Instead of starting with a patient’s own blood stem cells, which can require a somewhat traumatic harvest procedure, a new approach by a team at the Salk Institute in La Jolla creates iPS type stem cells by reprogramming the cells in a small skin sample. They mature those into blood stem cells and genetically modify them so that they can produce red blood cells that have the correct hemoglobin.

The Salk team uses a modified cold virus to carry the gene into the cell. ScienceDaily picked up the institute’s press release, which quotes one of the co-first authors on the study Mo Li on how the process works:

“It happens naturally, working like a zipper. The good gene just zips in perfectly, pushing the bad one out.”

CIRM funds other work by the senior author, Juan Carlos Izpisua Belmonte, but not this project. Because you never know which technology is going to work out best in the long term, it is nice to see other funders stepping up and pushing this alternative forward.

Heroic three-year study reveals safe methods for growing clinical-grade stem cells

Imagine seeking out the ideal pancake recipe: should you include sugar or no sugar? How about bleached vs. unbleached flour? Baking power or baking soda? When to flip the pancake on the skillet? You really have to test out many parameters to get that perfectly delicious light and fluffy pancake.

Essentially that’s what a CIRM-funded research team from both The Scripps Research Institute (TSRI) and UC San Diego accomplished but instead of making pancakes they were growing stem cells in the lab. In a heroic effect, they spent nearly three years systematically testing out different recipes and found conditions that should be safest for stem cell-based therapies in people. Their findings were reported today in PLOS ONE.

stem cells 2

Pluripotent stem cells. Courtesy of Andres Bratt-Leal from Jeanne Loring’s laboratory.

Let’s step back a bit in this story. If you’re a frequent reader of The Stem Cellar you know that one of the reasons stem cells are such an exciting field of biology is their pluripotency. That is, these nondescript cells have the capacity to become any type of cell in the body (pluri= many; potency = potential). This is true for embryonic stem cells and induced pluripotent cells (iPS). Several clinical trials underway or in development aim to harness this shape-shifting property to return insulin producing cells to people living with diabetes or to restore damaged nerves in victims of spinal cord injury, to name just two examples.

The other defining feature of pluripotent stem cell is their ability to make copies of themselves and grow indefinitely on petri dishes in the laboratory. As they multiply, the cells eventually take up all the real estate on the petri dish. If left alone the cells exhaust their liquid nutrients and die. So the cells must regularly be “passaged”; that is, removed from the dish and split into more dishes to provide new space to grow. This is also necessary for growing up enough quantities of cells for transplantation in people.

Previous small scale studies have observed that particular recipes for growing pluripotent cells can lead to genetic instability, such as deletion or duplication of DNA, that is linked with cancerous growth and tumor formation. This is perhaps the biggest worry about stem cell-based transplantation treatments: that they may cure disease but also cause cancer.

To find the conditions that minimize this genetic instability, the research team embarked on the first large-scale systematic study of the effects of various combinations of cell growth methods. One of the senior authors Louise Laurent, assistant professor at UC San Diego, explained in a press release the importance of this meticulous, quality control study:

“The processes used to maintain and expand stem cell cultures for cell replacement therapies needs to be improved, and the resulting cells carefully tested before use.”

To seek the ideal recipe, the team tested several parameters. For example, they grew some cells on top of so-called “feeder cells”, which help the stem cells grow while other cells used feeder-free conditions. Two different passaging methods were examined: one uses an enzyme solution to strip the cells off the petri dish while in the other method the cells are manually removed. Different liquid nutrients for the cell were included in the study as well. The different combinations of cells were grown continuously through 100 passages and changes in their genetic stability were periodically analyzed along the way.

loring_jeanne

Jeanne Loring (above) is professor of developmental neurobiology at TSRI and senior author of the study with Louise Laurent of the University of California, San Diego.

The long-term experiment paid off: the team found that the stem cells grown on feeder free petri dishes and passaged using the enzyme solution accumulated more genetic abnormalities than cells grown on feeder cells and passaged manually. The team also observed genetic changes after many cells passages. In particular, a recurring deletion of a gene called TP53. This gene is responsible for making a protein that acts to suppress cancers. So without this suppressor, later cell passages have the danger of becoming cancerous.

Based on these results, the other senior author, Jeanne Loring, a professor of developmental neurobiology at TSRI, gave this succinct advice:

“If you want to preserve the integrity of the genome, then grow your cells under those conditions with feeder cells and manual passaging. Also, analyze your cells—it’s really easy.”

Stem cell stories that caught our eye; progress toward artificial brain, teeth may help the blind and obesity

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.

More progress toward artificial brain. A team at the RIKEN Institute in Japan has used stem cells in a 3-D culture to create brain tissue more complex than prior efforts and from an area of the brain not produced before, the cerebellum—that lobe at the lower back of the brain that controls motor function and attention. As far back as 2008, a RIKEN team had created simple tissue that mimicked the cortex, the large surface area that controls memory and language.

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The Inquisitr web portal wrote a feature on a wide variety of efforts to create an artificial brain teeing off of this week’s publication of the cerebellum work in Cell Reports. The piece is fairly comprehensive covering computerized efforts to give robots intelligence and Europe’s Human Brain Project that is trying to map all the activity of the brain as a starting point for recapitulating it in the lab.

The experts interviewed included Robert Caplan of Tufts University in Massachusetts who is using 3-D scaffolding to build functional brain tissues that can process electrical signals. He is not planning any Frankenstein moments; he hopes to create models to improve understanding of brain diseases.

“Ideally we would like to have a laboratory brain system that recapitulates the most devastating diseases. We want to be able to take our existing toolkit of drugs and understand how they work instead of using trial and error.”

Teeth eyed as source of help for the blind. Today the European Union announced the first approval of a stem cell therapy for blindness. And already yesterday a team at the University of Pittsburg announced they had developed a new method to use stem cells to restore vision that could expand the number of patients who could benefit from stem cell therapy.

Many people have lost part or all their vision due to damage to the cornea on the surface of their eye. Even when they can gain vision back through a corneal transplant, their immune system often rejects the new tissue. So the ideal would be making new corneal tissue from the patient’s own cells. The Italian company that garnered the EU approval does this in patients by harvesting some of their own cornea-specific stem cells, called limbal stem cells. But this is only an option if only one eye is impacted by the damage.

The Pittsburgh team thinks it may have found an unlikely alternative source of limbal cells: the dental pulp taken from teeth that have be extracted. It is not as far fetched at it sounds on the surface. Teeth and the cornea both develop in the same section of the embryo, the cranial neural crest. So, they have a common lineage.

The researchers first treated the pulp cells with a solution that makes them turn into the type of cells found in the cornea. Then they created a fiber scaffold shaped like a cornea and seeded the cells on it. Many steps remain before people give up a tooth to regain their sight, but this first milestone points the way and was described in a press release from the journal Stem Cells Translational Medicine, which was picked up by the web site ClinicaSpace.

CIRM funds a project that also proposes to use the patient’s own limbal stem cells but using methods more likely to gain approval of the Food and Drug Administration than those used by the Italian company.

Stem cells and the fight against obesity. Of the two types of stem cells found in your bone marrow, one can form bone and cartilage and, all too often, fat. Preventing these stem cells from maturing into fat may be a tool in the fight against obesity according to a team at Queen Mary University of London.

The conversion of stem cells to fat seems to involve the cilia, or hair-like projections found on cells. When the cilia lengthen the stem cells progress toward becoming fat. But if the researchers genetically prevented that lengthening, they stopped the conversion to fat cells. The findings opens several different ways to think about understanding and curbing obesity says Melis Dalbay one of the authors of the study in a university press release picked up by ScienceNewsline.

“This is the first time that it has been shown that subtle changes in primary cilia structure can influence the differentiation of stem cells into fat. Since primary cilia length can be influenced by various factors including pharmaceuticals, inflammation and even mechanical forces, this study provides new insight into the regulation of fat cell formation and obesity.”

Stem cell stories that caught our eye: Cancer genetics, cell fate, super donors and tale of road to diabetes cure

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.

For cancer growth timing is everything. A study originating at the University of Southern California suggests tumors are born to be bad. Mutations constantly occur during the life of a tumor but those that occur early on determine if a tumor will grow as a benign mass of a cancerous one that spreads.

Describing the genetic markers the team found, the senior author, Christina Curtis, who recently moved to Stanford, was quoted in a story in ScienceBlog:

“What you see in the final cancer was there from the beginning.”

The CIRM funded team completed detailed genetic analysis of tumor cells surgically removed from colon cancer patients. Doctors treating these patients have long been hampered by an inability to tell which tumors will remain small and benign and which will develop into full-blown cancer. The researchers suggest the genetic fingerprints they have uncovered could lead to improved diagnosis for patients.

Physical forces also key to cell fate.
Putting the squeeze on stem cells may be what’s needed to get them to become bone. In this case, a team at the University of California, San Diego, used teeny tiny tweezers called “optical tweezers,” to trigger key internal signals that directed stem cells to go down the path to bone.

Pressure results in release of a cell signal shown in red

Pressure results in release of a cell signal shown in red

We have frequently written about the tremendous importance of a stem cell’s environment—its neighborhood if you will—in determining its fate. Yingxiao Wang, who led the study, described this role in a press release from the university picked up by ScienceNewsline:

“The mechanical environment around a stem cell helps govern a stem cell’s fate. Cells surrounded in stiff tissue such as the jaw, for example, have higher amounts of tension applied to them, and they can promote the production of harder tissues such as bone.”

He said the findings should help researchers trying to replicate the natural stem cell environment in the lab when they try to grow replacement tissues for patients.

Super donors could provide matching tissue.
One of the biggest challenges of using stem cells to replace damaged tissue is avoiding immune system rejection of the new cells. CIRM-grantee Cellular Dynamics International (CDI) announced this week that they have made key initial steps to creating a cell bank that could make this much easier.

Our bodies use molecules on the surface of our cells to identify tissue that is ours versus foreign such as bacteria. The huge variation in those molecules, called HLA, makes the matching needed for donor organ, or donor cells, more difficult than the New York Times Sunday crossword. But a few individuals posses an HLA combination that allows them to match to a large percent of the population.

CDI has now created clinical grade stem cell lines using iPS reprogramming of adult tissue from two such “super donors.” Just those two cell lines provide genetic matches for 19 percent of the population. The company plans to develop additional lines from other super donors with the goal of creating a bank that would cover 95 percent of the population.

Reuters picked up the company’s press release. CIRM does not fund this project, but we do fund another cell bank for which CDI is creating cells to better understand the causes of 11 diseases that have complex genetic origins

Narrative tells the tale of developing diabetes therapy. MIT Technology Review has published a well-told feature about the long road to creating a stem cell-based therapy for diabetes. Author Bran Alexander starts with the early days of the “stem cell wars” and carries the tale through treatment of the first patients in the CIRM-funded clinical trial being carried out by ViaCyte and the University of California, San Diego.

The piece quotes Viacyte’s chief scientific officer Kevin D’Amour about the long road:

“When I first came to ViaCyte 12 years ago, cell replacement through stem cells was so obvious. We all said, ‘Oh, that’s the low-hanging fruit.’ But it turned out to be a coconut, not an apple.”

But the article shows that with Viacyte’s product as well as others coming down the pike, that coconut has been cracked and real hope for diabetics lies inside.