Stem cell stories that caught our eye: spinal cord injury trial update, blood stem cells in lungs, and using parsley for stem cell therapies

More good news on a CIRM-funded trial for spinal cord injury. The results are now in for Asterias Biotherapeutics’ Phase 1/2a clinical trial testing a stem cell-based therapy for patients with spinal cord injury. They reported earlier this week that six out of six patients treated with 10 million AST-OPC1 cells, which are a type of brain cell called oligodendrocyte progenitor cells, showed improvements in their motor function. Previously, they had announced that five of the six patients had shown improvement with the jury still out on the sixth because that patient was treated later in the trial.

 In a news release, Dr. Edward Wirth, the Chief Medical officer at Asterias, highlighted these new and exciting results:

 “We are excited to see the sixth and final patient in the AIS-A 10 million cell cohort show upper extremity motor function improvement at 3 months and further improvement at 6 months, especially because this particular patient’s hand and arm function had actually been deteriorating prior to receiving treatment with AST-OPC1. We are very encouraged by the meaningful improvements in the use of arms and hands seen in the SciStar study to date since such gains can increase a patient’s ability to function independently following complete cervical spinal cord injuries.”

Overall, the trial suggests that AST-OPC1 treatment has the potential to improve motor function in patients with severe spinal cord injury. So far, the therapy has proven to be safe and likely effective in improving some motor function in patients although control studies will be needed to confirm that the cells are responsible for this improvement. Asterias plans to test a higher dose of 20 million cells in AIS-A patients later this year and test the 10 million cell dose in AIS-B patients that a less severe form of spinal cord injury.

 Steve Cartt, CEO of Asterias commented on their future plans:

 “These results are quite encouraging, and suggest that there are meaningful improvements in the recovery of functional ability in patients treated with the 10 million cell dose of AST-OPC1 versus spontaneous recovery rates observed in a closely matched untreated patient population. We look forward to reporting additional efficacy and safety data for this cohort, as well as for the currently-enrolling AIS-A 20 million cell and AIS-B 10 million cell cohorts, later this year.”

Lungs aren’t just for respiration. Biology textbooks may be in need of some serious rewrites based on a UCSF study published this week in Nature. The research suggests that the lungs are a major source of blood stem cells and platelet production. The long prevailing view has been that the bone marrow was primarily responsible for those functions.

The new discovery was made possible by using special microscopy that allowed the scientists to view the activity of individual cells within the blood vessels of a living mouse lung (watch the fascinating UCSF video below). The mice used in the experiments were genetically engineered so that their platelet-producing cells glowed green under the microscope. Platelets – cell fragments that clump up and stop bleeding – were known to be produced to some extent by the lungs but the UCSF team was shocked by their observations: the lungs accounted for half of all platelet production in these mice.

Follow up experiments examined the movement of blood cells between the lung and bone marrow. In one experiment, the researchers transplanted healthy lungs from the green-glowing mice into a mouse strain that lacked adequate blood stem cell production in the bone marrow. After the transplant, microscopy showed that the green fluorescent cells from the donor lung traveled to the host’s bone marrow and gave rise to platelets and several other cells of the immune system. Senior author Mark Looney talked about the novelty of these results in a university press release:

Mark Looney, MD

“To our knowledge this is the first description of blood progenitors resident in the lung, and it raises a lot of questions with clinical relevance for the millions of people who suffer from thrombocytopenia [low platelet count].”

If this newfound role of the lung is shown to exist in humans, it may provide new therapeutic approaches to restoring platelet and blood stem cell production seen in various diseases. And it will give lung transplants surgeons pause to consider what effects immune cells inside the donor lung might have on organ rejection.

Add a little vanilla to this stem cell therapy. Typically, the only connection between plants and stem cell clinical trials are the flowers that are given to the patient by friends and family. But research published this week in the Advanced Healthcare Materials journal aims to use plant husks as part of the cell therapy itself.

Though we tend to focus on the poking and prodding of stem cells when discussing the development of new therapies, an equally important consideration is the use of three-dimensional scaffolds. Stem cells tend to grow better and stay healthier when grown on these structures compared to the flat two-dimensional surface of a petri dish. Various methods of building scaffolds are under development such as 3D printing and designing molds using materials that aren’t harmful to human tissue.

Human fibroblast cells growing on decellularized parsley.
Image: Gianluca Fontana/UW-Madison

But in the current study, scientists at the University of Wisconsin-Madison took a creative approach to building scaffolds: they used the husks of parsley, vanilla and orchid plants. The researchers figured that millions of years of evolution almost always leads to form and function that is much more stable and efficient than anything humans can create. Lead author Gianluca Fontana explained in a university press release how the characteristics of plants lend themselves well to this type of bioengineering:

Gianluca Fontana, PhD

“Nature provides us with a tremendous reservoir of structures in plants. You can pick the structure you want.”

The technique relies on removing all the cells of the plant, leaving behind its outer layer which is mostly made of cellulose, long chains of sugars that make up plant cell walls. The resulting hollow, tubular husks have similar shapes to those found in human intestines, lungs and the bladder.

The researchers showed that human stem cells not only attach and grow onto the plant scaffolds but also organize themselves in alignment with the structures’ patterns. The function of human tissues rely on an organized arrangement of cells so it’s possible these plant scaffolds could be part of a tissue replacement cell product. Senior author William Murphy also points out that the scaffolds are easily altered:

William Murphy, PhD

“They are quite pliable. They can be easily cut, fashioned, rolled or stacked to form a range of different sizes and shapes.”

And the fact these scaffolds are natural products that are cheap to manufacture makes this a project well worth watching.

Stem cell stories that caught our eye: building an embryo and reviving old blood stem cells

Building an embryo in the lab from stem cells
The human body has been studied for centuries yet little is known about the first 14 days of human development when the fertilized embryo implants into the mother’s uterus and begins to divide and grow. Being able to precisely examine this critical time window may help researchers better understand why 75% of conceptions never implant and why 30% of pregnancies end in miscarriage.

This lack of knowledge is due in part to a lack of embryos to study. Researchers rely on embryos donated by couples who’ve gone through in vitro fertilization to get pregnant and have left over embryos that are otherwise discarded. Using mouse stem cells, a research team from Cambridge University reports today in Nature that they’ve generated a cellular structure that has the hallmarks of a fertilized embryo.

embryo

Stem cell-modeled mouse embryo (left) Mouse embryo (right); The red part is embryonic and the blue extra-embryonic.
Credit: Sarah Harrison and Gaelle Recher, Zernicka-Goetz Lab, University of Cambridge

This technique has been tried before without success. The breakthrough here was in the types of cells used. Rather that only relying on embryonic stems cells (ESCs), this study also included extra-embryonic trophoblast stem cells (TSCs), the cell type that goes on to form the placenta.

When grown on a 3D scaffold made from biological materials, the two cell types self-organized themselves into a pattern that closely resembles the early development of a true embryo. In a press release that was picked up by many media outlets, senior author Zernicka-Goetz spoke about the importance of including both TSCs and ESCs:

“We knew that interactions between the different types of stem cell are important for development, but the striking thing that our new work illustrates is that this is a real partnership – these cells truly guide each other. Without this partnership, the correct development of shape and form and the timely activity of key biological mechanisms doesn’t take place properly.”

The researchers think that lab-made embryos from mouse or human stem cells have little chance of developing into a fetus because other cell types critical for continued growth are not included. And there’s much to be learned by focusing on these very early events:

“We are very optimistic that this will allow us to study key events of this critical stage of human development without actually having to work on embryos.  Knowing how development normally occurs will allow us to understand why it so often goes wrong,” says Zernicka-Goetz.

Reviving old blood stem cells, part 1: repair the garbage collectors
One of the reasons that our bodies begin to deteriorate in old age is a weakening, dysfunctional immune system that increases the risk for serious infection, blood cancers and chronic inflammatory diseases like atherosclerosis (hardening of the arteries). Reporting this week in Nature, a UCSF research team presents evidence that a breakdown in our cell’s natural garbage collecting system may be partially to blame.

The team focused on a process called autophagy (literally meaning self “auto”-eating “phagy”) that keeps cells functioning properly by degrading faulty proteins and cellular structures. In particular, they examined autophagy in blood-forming stem cells, which give rise to all the cell types of the immune system. They found that autophagy was not working in 70 percent of blood stem cells from old mice. And these cells had all the hallmarks of an old cell. And the other 30 percent? In those cells, autophagy was fully functional and they looked like blood stem cells found in young mice.

The team went on to show that in blood stem cells, autophagy had an additional role that until now had not been observed: it helped slow the activity of the stem cells back to its default state by gobbling up excess mitochondria, the structures that produces a cell’s energy needs. Without this quieting of the stem cell, the over-active mitochondria led to chemical modification of the cell’s DNA that disrupted the blood stem cells’ ability to give rise to a proper balance of immune cells. In fact, young mice with genetic modifications that block autophagy generated blood stem cells with these old age-related characteristics.

But the researchers were also able to restore autophagy in blood stem cells collected from old mice by adding various drugs. Team lead Emmanuelle Passegué is optimistic this result could be translated into a therapeutic approach:

“This discovery might provide an interesting therapeutic angle to use in re-activating autophagy in all of the old HSCs, to slow the aging of the blood system and to improve engraftment during bone marrow or HSC transplantation,” Passegué said in a university press release.

Reviving old blood stem cells, part 2: fix the aging neighborhood
Another study this week focused on age-related disruptions in the function of blood stem cells but in this case an aging neighborhood is to blame. Blood stem cells form and hang out in areas of the bone marrow called niches. Researchers at the Cincinnati Children’s Hospital Medical Center and the University of Ulm in Germany reported this week in EMBO that the age of the niche affects blood stem cell function.

bonemarrow

Microscopy of bone marrow. Red staining indicates osteopotin, blue staining indicates cell nuclei. Credit: University of Ulm

 

When blood stem cells from two-year old mice were transplanted into the bone marrow of eight-week old mice, the older stem cells took on characteristics of young stem cells including an enhance ability to form all the different cell types of the immune system. In trying to understand what was going on, the researchers focused on a bone marrow cell called an osteoblast which gives rise to bone. Osteoblasts produce osteopontin, a protein that plays an important role in the structure of the bone marrow. The team showed that as the bone marrow ages, osteopontin levels go down. And this reduction had effects on the health of blood stem cells. But, as team lead Hartmut Geiger mentions in a press release, this impact could be reversed which points to a potential new therapeutic strategy for age-related disease:

“We show that the place where HSCs form in the bone marrow loses osteopontin upon aging, but if you give back the missing protein to the blood-forming cells they suddenly rejuvenate and act younger. Our study points to exciting novel ways to have a better immune system and possibly less blood cancer upon aging by therapeutically targeting the place where blood stem cells form.”

Reducing animal testing with stem cells and electronic petri dishes

botoxThough the celebrities at Sunday’s Academy Awards worked hard to sport unique clothing and hair styles, I bet many had something in common: Botox injections. Botox, an FDA-approved, marketed form of Botulism neurotoxin, is well known for its wrinkle reducing effects. The neurotoxin’s other claim to fame is the fact that it’s the most lethal, naturally occurring poison known. Inhaling a minuscule amount – just 0.0000007 grams! – is enough to kill a 150 pound person.

Much smaller, non-lethal doses of Botulism neurotoxin are obviously used for its cosmetic application. It’s also used to treat a wide range of disorders including back pain, migraines and muscle spasms related to stroke and cerebral palsy. Because the toxin is produced naturally by the Clostridium botulinum bacteria, the amount of toxin can vary in each batch during the manufacturing process. So, it’s critical to carefully analyze the Botulism neurotoxin dose.  The standard test which has been around since the 1920’s is the mouse bioassay. During the test, increasing concentrations of the neurotoxin are injected into mice which are then observed for signs of paralysis (Botulism neurotoxin acts by blocking communication between nerves and muscle).

As you might expect, the lab mice suffer during the test, sometimes suffocating during the process. Because of the large market for these Botulism neurotoxin-based products, it’s estimated that about 600,000 laboratory mice in US and Europe are killed via the mouse bioassay each year. Though the media often portrays scientists as callous, cold-hearted people that couldn’t care less about the welfare of their lab animals, in reality, it’s just the opposite. Case in point: a research group at the University of Bern in Switzerland reported this week in Frontiers in Pharmacology that they have devised an alternative system that could help make this mouse bioassay obsolete.

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Multi-electrode assay petri dish. Credit: Multichannel Systems

To set up this new assay system, the researchers relied on mouse embryonic stem cells. The researchers added chemicals to the cells, stimulating them to transform into nerve cells, or neurons. These stem cell-derived neurons were placed in specialized petri dishes that look something like a computer chip. Wired with mini electrodes, the lab dishes allowed the continuous recording of electrical signals generated by the neurons. Adding small doses of Botox to the cells, the scientists could detect a shutdown of the neuron signaling which is the same underlying effect that causes paralysis in the mouse bioassay.

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Stem cell-derived neurons (green) grown on electrodes (outlined in white) allows monitoring of electrical nerve signals. Credit: Stephen Jenkinson, Institute for Infectious Diseases, University of Bern

This sensitive test could have applications beyond the detection of Botulism neurotoxin. The electrode dishes are easy to scale up and do not require highly trained staff. So, without the need for expensive animal testing, this system could be used as a high throughput drug screening platform to find other substances that have beneficial effects on neuron signaling.

Rhythmic brain circuits built from stem cells

The TV commercial is nearly 20 years old but I remember it vividly: a couple is driving down a street when they suddenly realize the music on their tape deck is in sync with the repetitive activity on the street. From the guy casually dribbling a basketball to people walking along the sidewalk to the delivery people passing packages out of their truck, everything and everyone is moving rhythmically to the beat.

The ending tag line was, “Sometimes things just come together,” which is quite true. Many of our basic daily activities like breathing and walking just come together as a result of repetitive movement. It’s easy to take them for granted but those rhythmic patterns ultimately rely on very intricate, interconnected signals between nerve cells, also called neurons, in the brain and spinal cord.

Circuitoids: a neural network in a lab dish

A CIRM-funded study published yesterday in eLife by Salk Institute scientists reports on a method to mimic these repetitive signals in a lab dish using neurons grown from embryonic stem cells. This novel cell circuitry system gives the researchers a tool for gaining new insights into neurodegenerative diseases, like Parkinson’s and ALS, and may even provide a means to fix neurons damaged by injury or disease.

The researchers changed or specialized mouse embryonic stem cells into neurons that either stimulate nerve signals, called excitatory neurons, or neurons that block nerve signals, called inhibitory neurons. Growing these groups of cells together led to spontaneous rhythmic nerve signals. These clumps of cells containing about 50,000 neurons each were dubbed circuitoids by the team.

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Confocal microscope immunofluorescent image of a spinal cord neural circuit made entirely from stem cells and termed a “circuitoid.” Credit: Salk Institute.

Making neural networks dance to a different beat

A video produced by the Salk Institute (see below), shows some fascinating microscopy visualizations of these circuitoids’ repetitive signals. In the video, team leader Samuel Pfaff explains that changing the ratio of excitatory vs inhibitory neurons had noticeable effects on the rhythm of the nerve impulses:

“What we were able to do is combine different ratios of cell types and study properties of the rhythmicity of the circuitoid. And that rhythmicity could be very tightly control depending on the cellular composition of the neural networks that we were forming. So we could regulate the speed [of the rhythmicity] which is kind of equivalent to how fast you’re walking.”

It’s possible that the actual neural networks in our brains have the flexibility to vary the ratio of the active excitatory to inhibitory neurons as a way to allow adjustments in the body’s repetitive movements. But the complexity of those networks in the human brain are staggering which is why these circuitoids could help:

Samuel Pfaff. (Salk Institute)

Samuel Pfaff. (Salk Institute)

“It’s still very difficult to contemplate how large groups of neurons with literally billions if not trillions of connections take information and process it,” says Pfaff in a press release. “But we think that developing this kind of simple circuitry in a dish will allow us to extract some of the principles of how real brain circuits operate. With that basic information maybe we can begin to understand how things go awry in disease.”

Wishing You and Your Stem Cells a Happy Valentine’s Day!

cirm-valentines-day

Roses are Red, 

Violets are Blue,

 Let’s thank pluripotent stem cells,

For making humans like me and you

Happy Valentine’s Day from me and everyone at CIRM! Today, we are celebrating this day of love by sending our warmest wishes to you our readers. We’re grateful for your interest in learning more about stem cells and your steadfast support for the advancement of stem cell research.

We also want to wish a Happy Valentine’s Day to your stem cells, yes that’s right the stem cells you have in your body. Without pluripotent stem cells, which are embryonic cells that generate all the cells in your body, humans wouldn’t exist. And without adult stem cells, which live in your tissues and organs, we wouldn’t have healthy, functioning bodies.

So, as you’re wishing your loved ones, friends, and colleagues a Happy Valentine’s Day, take a moment to thank your body and the stem cells living in it for keeping you alive.

I’ll leave you with a few Valentine’s Day themed stem cell blogs for you to enjoy. Have a wonderful day!


Valentine’s Day Themed Blogs:

1) Toronto Scientists Have an Affair with the Heart by OIRMexpression

Ventricular heart muscle cells. Image courtesy of Dr. Michael Laflamme

Ventricular heart muscle cells. Image courtesy of Dr. Michael Laflamme

2) A Cardiac Love Triangle: How Transcription Factors Interact to Make a Heart by the Stem Cellar

© Gladstone Institutes photo credit: Kim Cordes / Gladstone Institute Lay Description: In this image, human embryonic stem cells have been differentiated into cardiomyocytes, or heart muscle cells, and stained to show the expression of cardiac Troponin T (red), a protein that helps cardiomyocytes to contract, and cell nuclei (blue). Scientific Description: Cultured human iPSCs reprogrammed into CMs. Stain for cTnT (red), and DAPI (blue). Original caption: cardiomyocytes.tif

Heart cells made from human induced pluripotent stem cells. © Gladstone Institutes
photo credit: Kim Cordes / Gladstone Institute

3) Stem Cells on Valentine’s Day: Update on Cardiac Regenerative Medicine by Paul Knoepfler on the Niche Blog

4) Hope For Broken Hearts this Valentine’s Day – a Clinical Trial to Repair the Damage by the Stem Cellar


Special thanks to Samantha Yammine for letting us her her “Icy Astrocytes” photo in our Valentine’s Day graphic.

Stem Cell Stories That Caught our Eye: Making blood and muscle from stem cells and helping students realize their “pluripotential”

Stem cells offer new drug for blood diseases. A new treatment for blood disorders might be in the works thanks to a stem cell-based study out of Harvard Medical School and Boston Children’s hospital. Their study was published in the journal Science Translational Medicine.

The teams made induced pluripotent stem cells (iPSCs) from the skin of patients with a rare blood disorder called Diamond-Blackfan anemia (DBA) – a bone marrow disease that prevents new blood cells from forming. iPSCs from DBA patients were then specialized into blood progenitor cells, the precursors to blood cells. However, these precursor cells were incapable of forming red blood cells in a dish like normal precursors do.

Red blood cells were successfully made via induced pluripotent stem cells from a Diamond-Blackfan anemia patient. Image: Daley lab, Boston Children’s

Red blood cells were successfully made via induced pluripotent stem cells from a Diamond-Blackfan anemia patient. Image: Daley lab, Boston Children’s

The blood progenitor cells from DBA patients were then used to screen a library of compounds to identify drugs that could get the DBA progenitor cells to develop into red blood cells. They found a compound called SMER28 that had this very effect on progenitor cells in a dish. When the compound was tested in zebrafish and mouse models of DBA, the researchers observed an increase in red blood cell production and a reduction of anemia symptoms.

Getting pluripotent stem cells like iPSCs to turn into blood progenitor cells and expand these cells into a population large enough for drug screening has not been an easy task for stem cell researchers.

Co-first author on the study, Sergei Doulatov, explained in a press release, “iPS cells have been hard to instruct when it comes to making blood. This is the first time iPS cells have been used to identify a drug to treat a blood disorder.”

In the future, the researchers will pursue the questions of why and how SMER28 boosts red blood cell generation. Further work will be done to determine whether this drug will be a useful treatment for DBA patients and other blood disorders.

 

Students realize their “pluripotential”. In last week’s stem cell stories, I gave a preview about an exciting stem cell “Day of Discovery” hosted by USC Stem Cell in southern California. The event happened this past Saturday. Over 500 local middle and high school students attended the event and participated in lab tours, poster sessions, and a career resource fair. Throughout the day, they were engaged by scientists and educators about stem cell science through interactive games, including the stem cell edition of Family Feud and a stem cell smartphone videogame developed by USC graduate students.

In a USC press release, Rohit Varma, dean of the Keck School of Medicine of USC, emphasized the importance of exposing young students to research and scientific careers.

“It was a true joy to welcome the middle and high school students from our neighboring communities in Boyle Heights, El Sereno, Lincoln Heights, the San Gabriel Valley and throughout Los Angeles. This bright young generation brings tremendous potential to their future pursuits in biotechnology and beyond.”

Maria Elena Kennedy, a consultant to the Bassett Unified School District, added, “The exposure to the Keck School of Medicine of USC is invaluable for the students. Our students come from a Title I School District, and they don’t often have the opportunity to come to a campus like the Keck School of Medicine.”

The day was a huge success with students posting photos of their experiences on social media and enthusiastically writing messages like “stem cells are our future” and “USC is my goal”. One high school student acknowledged the opportunity that this day offers to students, “California currently has biotechnology as the biggest growing sector. Right now, it’s really important that students are visiting labs and learning more about the industry, so they can potentially see where they’re going with their lives and careers.”

You can read more about USC’s Stem Cell Day of Discovery here. Below are a few pictures from the event courtesy of David Sprague and USC.

Students have fun with robots representing osteoblast and osteoclast cells at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

Students have fun with robots representing osteoblast and osteoclast cells at the USC Stem Cell Day of Discovery. Photo by David Sprague

Dr. Francesca Mariana shows off a mouse skeleton that has been dyed to show bones and cartilage at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

Dr. Francesca Mariana shows off a mouse skeleton that has been dyed to show bones and cartilage. Photo by David Sprague

USC masters student Shantae Thornton shows students how cells are held in long term cold storage tanks at -195 celsius at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

USC masters student Shantae Thornton shows students how cells are held in long term cold storage tanks at -195 celsius. Photo by David Sprague

Genesis Archila, left, and Jasmine Archila get their picture taken at the Stem Cell Day of Discovery event held at the USC Health Sciences Campus in Los Angeles, CA. February 4th, 2017. The event encourages students to learn more about STEM opportunities, including stem cell study and biotech, and helps demystify the fields and encourage student engagement. Photo by David Sprague

Genesis Archila, left, and Jasmine Archila get their picture taken at the USC Stem Cell Day of Discovery. Photo by David Sprague

New stem cell recipes for making muscle: new inroads to study muscular dystrophy (Todd Dubnicoff)

Embryonic stem cells are amazing because scientists can change or specialize them into virtually any cell type. But it’s a lot easier said than done. Researchers essentially need to mimic the process of embryo development in a petri dish by adding the right combination of factors to the stem cells in just the right order at just the right time to obtain a desired type of cell.

Making human muscle tissue from embryonic stem cells has proven to be a challenge. The development of muscle, as well as cartilage and bone, are well characterized and known to form from an embryonic structure called a somite. Researches have even been successful working out the conditions for making somites from animal stem cells. But those recipes didn’t work well with human stem cells.

Now, a team of researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA has overcome this roadblock by carrying out a systematic approach using human tissue. As described in Cell Reports, the scientists isolated somites from early human embryos and studied their gene activity. By comparing somites that were just beginning to emerge with fully formed somites, the researchers pinpointed differences in gene activity patterns. With this data in hand, the team added factors to the cells that were known to affect the activity of those genes. Through some trial and error, they produced a recipe – different than those used in animal cells – that could convert 90 percent of the human stem cells into somites in only four days. Those somites could then readily transform into muscle or bone or cartilage.

This new method for making human muscle will be critical for the lab’s goal to develop therapies for Duchenne muscular dystrophy, an incurable muscle wasting disease that strikes young boys and is usually fatal by their 20’s.

The new protocol turned 90 percent of human pluripotent stem cells into somite cells in just four days; those somite cells then generated (left to right) cartilage, bone and muscle cells.  Image: April Pyle Lab/UCLA

The new protocol turned 90 percent of human pluripotent stem cells into somite cells in just four days; those somite cells then generated (left to right) cartilage, bone and muscle cells. Image: April Pyle Lab/UCLA

Curing the Incurable through Definitive Medicine

“Curing the Incurable”. That was the theme for the first annual Center for Definitive and Curative Medicine (CDCM) Symposium held last week at Stanford University, in Palo Alto, California.

The CDCM is a joint initiative amongst Stanford Healthcare, Stanford Children’s Health and the Stanford School of Medicine. Its mission is to foster an environment that accelerates the development and translation of cell and gene therapies into clinical trials.

The research symposium focused on “the exciting first-in-human cell and gene therapies currently under development at Stanford in bone marrow, skin, cardiac, neural, pancreatic and neoplastic diseases.” These talks were organized into four different sessions: cell therapies for neurological disorders, stem cell-derived tissue replacement therapies, genome-edited cell therapies and anti-cancer cell-based therapies.

A few of the symposium speakers are CIRM-funded grantees, and we’ll briefly touch on their talks below.

Targeting cancer

The keynote speaker was Irv Weissman, who talked about hematopoietic or blood-forming stem cells and their value as a cell therapy for patients with blood disorders and cancer. One of the projects he discussed is a molecule called CD47 that is found on the surface of cancer cells. He explained that CD47 appears on all types of cancer cells more abundantly than on normal cells and is a promising therapeutic target for cancer.

Irv Weissman

Irv Weissman

“CD47 is the first gene whose overexpression is common to all cancer. We know it’s molecular mechanism from which we can develop targeted therapies. This would be impossible without collaborations between clinicians and scientists.”

 

At the end of his talk, Weissman acknowledged the importance of CIRM’s funding for advancing an antibody therapeutic targeting CD47 into a clinical trial for solid cancer tumors. He said CIRM’s existence is essential because it “funds [stem cell-based] research through the [financial] valley of death.” He further explained that CIRM is the only funding entity that takes basic stem cell research all the way through the clinical pipeline into a therapy.

Improving bone marrow transplants

judith shizuru

Judith Shizuru

Next, we heard a talk from Judith Shizuru on ways to improve current bone-marrow transplantation techniques. She explained how this form of stem cell transplant is “the most powerful form of cell therapy out there, for cancers or deficiencies in blood formation.” Inducing immune system tolerance, improving organ transplant outcomes in patients, and treating autoimmune diseases are all applications of bone marrow transplants. But this technique also carries with it toxic and potentially deadly side effects, including weakening of the immune system and graft vs host disease.

Shizuru talked about her team’s goal of improving the engraftment, or survival and integration, of bone marrow stem cells after transplantation. They are using an antibody against a molecule called CD117 which sits on the surface of blood stem cells and acts as an elimination signal. By blocking CD117 with an antibody, they improved the engraftment of bone marrow stem cells in mice and also removed the need for chemotherapy treatment, which is used to kill off bone marrow stem cells in the host. Shizuru is now testing her antibody therapy in a CIRM-funded clinical trial in humans and mentioned that this therapy has the potential to treat a wide variety of diseases such as sickle cell anemia, leukemias, and multiple sclerosis.

Tackling stroke and heart disease

img_1327We also heard from two CIRM-funded professors working on cell-based therapies for stroke and heart disease. Gary Steinberg’s team is using human neural progenitor cells, which develop into cells of the brain and spinal cord, to treat patients who’ve suffered from stroke. A stroke cuts off the blood supply to the brain, causing the death of brain cells and consequently the loss of function of different parts of the body.  He showed emotional videos of stroke patients whose function and speech dramatically improved following the stem cell transplant. One of these patients was Sonia Olea, a young woman in her 30’s who lost the ability to use most of her right side following her stroke. You can read about her inspiring recover post stem cell transplant in our Stories of Hope.

Dr. Joe Wu. (Image Source: Sean Culligan/OZY)

Dr. Joe Wu. (Image Source: Sean Culligan/OZY)

Joe Wu followed with a talk on adult stem cell therapies for heart disease. His work, which is funded by a CIRM disease team grant, involves making heart cells called cardiomyocytes from human embryonic stem cells and transplanting these cells into patient with end stage heart failure to improve heart function. His team’s work has advanced to the point where Wu said they are planning to file for an investigational new drug (IND) application with the US Food and Drug Administration (FDA) in six months. This is the crucial next step before a treatment can be tested in clinical trials. Joe ended his talk by making an important statement about expectations on how long it will take before stem cell treatments are available to patients.

He said, “Time changes everything. It [stem cell research] takes time. There is a lot of promise for the future of stem cell therapy.”

Let’s Be Clear: Stem Cells and Popular Culture

The following is a guest blog from Matt Donne, PhD. Thoughts expressed here are not necessarily those of CIRM.

It was during winter break of my Junior year in college that the gap between the general public’s understanding of embryonic stem cell biology and the reality of that research quickly came into focus for me.

I was out to lunch with my grandmother and excited to see her to share my new research project I had started with human embryonic stem cells (hESCs). While enjoying our lunch together discussing school, relationships, and such, a friend of hers approached to say hello. Immediately my grandmother proclaimed, “This is my grandson Matthew and he is a scientist. He just started working with stem cells to cure cancer.”  Now this statement was not true, but harmless enough so I figured I would let it go. Her friend’s eyes immediately grew large and she quickly felt it necessary to educate us on what exactly I was doing by working with “stem cells”. In her friend’s words I was, “killing babies and sucking out their brains to make stem cells.”

My grandmother and I were both silenced and confused, for different reasons, as her friend quickly walked away in disgust. My grandmother asked concernedly if this was in fact true. I explained that this could not be farther from the truth, and that this friend was extremely misinformed. We then discussed the difference between a developing fetus and the 3 to 5 day old embryos from which these hESC lines were derived. We also discussed these embryos were donated by couples who seek in vitro fertilization (IVF) treatments. Specifically, the donated embryos were those which the couple no longer needed and therefore decided to donate them for research proposes to help advance both science and medicine rather than discard them. This fact-based explanation eased many of the fears my grandmother had as to the research. This, however, left in me a fear that over 10 years later I still see playing out in popular culture.

Most recently my frustration toward this misinformation came when I saw a posting by VICE of a carton entitled ‘Magical Stem Cells’. The cartoon was a truly gross and inaccurate representation of where embryonic stem cells are derived, as it portrayed a unicorn fetus essentially being harvested to create “magical” stem cells that can turn into any other cell, tissue or organ in the body. This is wholly inaccurate. It is possible that the cartoon was created to positively promote the potential of stem cell biology, however anyone somewhat versed in the field would find it misleading, disgusting, scary and dangerous.

Vice comic: Magical Stem Cells

Vice comic: Magical Stem Cells

Similarly, the creators of South Park several years back had an episode in which Christopher Reeves was essentially a spokesperson for the research and its potential to cure spinal cord injury. They equated stem cell therapies, like the VICE cartoon, to the use of fetal tissue for therapeutic purposes. Let’s be clear, stem cell biology and stem cell research does not universally mean the use of fetal tissue. In fact, most often the fields of stem cell biology are broken down into three main groups: hESCs, induced pluripotent stem cells (iPSCs, which are adult cells that have been re-engineered to have embryonic-like qualities), and the broader category of adult stem cells. Use of cells taken from aborted human fetuses, either for research or clinical trials, is in fact the exception to the rule.

The term “stem cell” was first used in 1877 when German biologist Ernst Haeckel wrote about a “stem cell” being the fertilized egg from which all cells of the placenta and body arise.1 In 1981, U.C. San Francisco’s Gail Martin became the first scientist to isolate pluripotent cells (which can turn into any other cell in the body) from mouse embryos and coined the term “embryonic stem cells” to describe them.2 It was not until 1998 that James Thomson created the first hESC lines.3

A few interesting facts about blastocyst stage embryos, which were the source of the first embryonic stem cell lines, are that they look the same in mice, humans, dogs, horses, and cows and are typically comprised of no more than several hundred cells. It is also important to note that embryonic stem cells, by definition, can only come from up to blastocyst stage embryos (about 5-7 days after fertilization). Cells taken from embryos older than the blastocyst stage have already begun specializing into specific cell lineages, and are no longer capable of making all cell types.

This, I think, is extremely important to emphasize, as too many people seem to believe that we get our embryonic stem cells from fetuses. I think it is also important to point out that now several groups have published on potential “embryo-safe” methods of embryonic stem cell derivation4-6, which use a single cell from the early, cleavage stage embryo for derivation. This removal of a single cell from such an early stage embryo has been demonstrated to have no negative consequences to the developing embryo, as it has been used for years in IVF clinics. Development of this technique in turn can help alleviate some of the ethical concerns that people have about the use of donated human embryos for research. Lastly, advances in the techniques and use of both iPSCs and adult stem cells alleviate any potential concerns raised by hESCs.

What I hope to achieve in this opinion piece is to raise a general awareness that some commonly held views on stem cells need to be overturned. This can only happen through continued open conversations and discussions. An important way to achieve this is through outreach and education of young students to get them excited about science and the potential of stem cell biology. Resources such as CIRM’s free online education portal and Outschool’s online teaching platform are great example of how to make this happen. Using social media, such as Facebook and Twitter, to post peer-reviewed publications or review articles is another way to make a positive impact.

There are so many amazing things happening in the various fields of stem cell biology that now, more than ever, it is important we lean on facts and push for communicating truths to further our progress of educating the public. What I ask of you at this point is to not sit back and shake your head when you see or read something you know is wrong, such as VICE’s “magical stem cells” cartoon. Please say something, and teach someone.   

Matt Donne

Matt Donne

Matt Donne recently finished his PhD in Developmental and Stem Cell Biology at the University of California, San Francisco, where he was awarded a CIRM Fellowship. Previously he was a CIRM student at San Francisco State University.  He has shared his passion for stem cell biology with students of all ages for over 10 years. His passion for stem cell biology and animals has brought him to VitroLabs, where he is changing how leather is manufactured.


Citations:

1          Ramalho-Santos, M. & Willenbring, H. On the origin of the term “stem cell”. Cell Stem Cell 1, 35-38, doi:10.1016/j.stem.2007.05.013 (2007).

2          Martin, G. R. Isolation of a pluripotent cell line from early mouse embryos cultured in medium conditioned by teratocarcinoma stem cells. Proc Natl Acad Sci U S A 78, 7634-7638 (1981).

3          Thomson, J. A. et al. Embryonic stem cell lines derived from human blastocysts. Science 282, 1145-1147 (1998).

4          Klimanskaya, I., Chung, Y., Becker, S., Lu, S. J. & Lanza, R. Human embryonic stem cell lines derived from single blastomeres. Nature 444, 481-485, doi:10.1038/nature05142 (2006).

5          Zdravkovic, T. et al. Human stem cells from single blastomeres reveal pathways of embryonic or trophoblast fate specification. Development 142, 4010-4025, doi:10.1242/dev.122846 (2015).

6          Chung, Y. et al. Human Embryonic Stem Cell Lines Generated without Embryo Destruction. Cell Stem Cell 2, 113-117, doi:http://dx.doi.org/10.1016/j.stem.2007.12.013 (2008).

Good news from Asterias’ CIRM-funded spinal cord injury trial

This week in the stem cell field, all eyes are on Asterias Biotherapeutics, a California-based company that’s testing a stem cell based-therapy in a CIRM-funded clinical trial for spinal cord injury patients. The company launched its Phase 1/2a clinical trial back in 2014 with the goal of determining the safety of the therapy and the optimal dose of AST-OPC1 cells to transplant into patients.

astopc1AST-OPC1 cells are oligodendrocyte progenitor cells derived from embryonic stem cells. These are cells located in the brain and spinal cord that develop into support cells that help nerve cells function and communicate with each other.

Asterias is transplanting AST-OPC1 cells into patients that have recently suffered from severe spinal cord injuries in their neck. This type of injury leaves patients paralyzed without any feeling from their neck down. By transplanting cells that can help the nerve cells at the injury site reform their connections, Asterias hopes that their treatment will allow patients to regain some form of movement and feeling.

And it seems that their hope is turning into reality. Yesterday, Asterias reported in a news release that five patients who received a dose of 10 million cells showed improvements in their ability to move after six months after their treatment. All five patients improved one level on the motor function scale, while one patient improved by two levels. A total of six patients received the 10 million cell dose, but so far only five of them have completed the six-month follow-up study, three of which have completed the nine-month follow-up study.

We’ve profiled two of these six patients previously on the Stem Cellar. Kris Boesen was the first patient treated with 10 million cells and has experienced the most improvement. He has regained the use of his hands and arms and can now feed himself and lift weights. Local high school student, Jake Javier, was the fifth patient in this part of the trial, and you can read about his story here.

Kris Boesen, CIRM spinal cord injury clinical trial patient.

Kris Boesen, CIRM spinal cord injury clinical trial patient.

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Jake Javier and his Mom

The lead investigator on this trial, Dr. Richard Fessler, explained the remarkable progress that these patients have made since their treatment:

“With these patients, we are seeing what we believe are meaningful improvements in their ability to use their arms, hands and fingers at six months and nine months following AST-OPC1 administration. Recovery of upper extremity motor function is critically important to patients with complete cervical spinal cord injuries, since this can dramatically improve quality of life and their ability to live independently.”

Asterias will continue to monitor these patients for changes or improvements in movement and will give an update when these patients have passed the 12-month mark since their transplant. However, these encouraging preliminary results have prompted the company to look ahead towards advancing their treatment down the regulatory approval pathway, out of clinical trials and into patients.

Asterias CEO, Steve Cartt, commented,

Steve Cartt, CEO of Asterias Biotherapeutics

Steve Cartt, CEO of Asterias Biotherapeutics

“These results to date are quite encouraging, and we look forward to initiating discussions with the FDA in mid-2017 to begin to determine the most appropriate clinical and regulatory path forward for this innovative therapy.”

 

Talking with the US FDA will likely mean that Asterias will need to show further proof that their stem cell-based therapy actually improves movement in patients, rather than the patients spontaneously regaining movement (which has been observed in patients before). FierceBiotech made this point in a piece they published yesterday on this trial.

“Those discussions with FDA could lead to a more rigorous examination of the effect of AST-OPC1. Some patients with spinal injury experience spontaneous recovery. Asterias has put together matched historical data it claims show “a meaningful difference in the motor function recovery seen to date in patients treated with the 10 million cell dose of AST-OPC1.” But the jury will remain out until Asterias pushes ahead with plans to run a randomized controlled trial.”

In the meantime, Asterias is testing a higher dose of 20 million AST-OPC1 cells in a separate group of spinal cord injury patients. They believe this number is the optimal dose of cells for achieving the highest motor improvement in patients.

2017 will bring more results and hopefully more good news about Asterias’ clinical trial for spinal cord injury. And as always, we’ll keep you informed with any updates on our Stem Cellar Blog.

Eye on the prize: two stem cell studies restore vision in blind mice

For the 39 million people in the world who are blind, a vision-restoring therapy would be the ultimate prize. So far, this prize has remained out of reach, but two studies published this week have entered the ring as promising contenders in the fight against blindness.

In the red corner, we have a study published in Stem Cell Reports from the RIKEN Institute in Japan led by scientist Masayo Takahashi. Her team restored vision in blind mice with an advanced stage of retinal disease by transplanting sheets of light-sensing photoreceptor cells that were made from induced pluripotent stem cells (iPSCs).

In the blue corner, we have a study published in Cell Stem Cell from the Buck Institute in California led by scientist Deepak Lamba. His team restored long-term vision in blind mice by transplanting embryonic stem cell-derived photoreceptor cells and preventing the immune system from rejecting the transplant.

Transplanting Retinal sheets

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Synaptic integration of graft retina into model mouse
Credit: RIKEN

Let’s first talk about the Riken study led by Masayo Takahashi. She is well known for her pioneering work on iPSC-derived treatments for macular degeneration – a disease that damages the retina and causes blindness.

In previous work, Takahashi and her team transplanted sheets of mouse stem cell-derived retinal progenitor cells, which mature into light-sensing cells called photoreceptors, into the eyes of mice. The cells within the sheet formed connections with the resident cells in the mouse eye, proving the feasibility of transplanting retinal sheets to restore vision.

In their current study, published in Stem Cell Reports, Takahashi’s team found that the retinal sheets could restore vision in mice that had a very severe form of retinal disease that left them unable to see light. After the mice received the retinal transplants, they responded to light, which they were unable to do previously. Like their other findings, they found that the cells in the transplant made connections with the host cells in the eye including nerve cells that send light-sensing signals to the brain.

First author on the study, Michiko Mandai explained the importance of their findings and their future plans in a news release,

“These results are a proof of concept for using iPSC-derived retinal tissue to treat retinal degeneration. We are planning to proceed to clinical trials in humans after a few more necessary studies using human iPSC-derived retinal tissue in animals. Clinical trials are the only way to determine how many new connections are needed for a person to be able to ‘see’ again.”

While excited by their results, Mandai and the rest of the RIKEN team aren’t claiming the prize for a successful treatment that will cure blindness in people just yet. Mandai commented,

“We cannot expect to restore practical vision at the moment. We will start from seeing a simple light, then possibly move on to larger figures in the next stage.”

Blocking the immune system

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Image showing transplanted GFP-expressing human stem cell derived photoreceptors (green) integrated in a host rodent retina stained for Otx2 (red).
Credit Jie Zhu, Buck Institute for Research on Aging

In the Buck Institute study, Lamba and his team took on the challenge of answering a controversial question about why retinal cell transplants typically don’t survive long-term in the eye. Some scientists think that the transplanted cells die off over time because they don’t integrate into the eye while others think that they are rejected and killed off by the immune system.

To answer this question, Lamba transplanted human embryonic stem cell-derived retinal cells into immunodeficient mice that lacked a protein receptor that’s vital for a functioning immune system. The retinal cells transplanted into immunodeficient mice survived much better than retinal cells transplanted into normal mice and developed into ten times as many photoreceptors that integrated themselves into the host eye.

Their next step was to transplant the retinal cells into mice that were blind and also lacked the same immune receptor as the other mice. After the transplant, the blind mice became responsive to light and showed brain activity associated with sensing light. Their newfound ability to see lasted for nine months to a year following the transplant.

Lamba believes that backing down the immune response is responsible for the long-term vision restoration in the blind mice. He explained the importance of their findings in a Buck Institute news release,

“That finding gives us a lot of hope for patients, that we can create some sort of advantage for these stem cell therapies so it won’t be just a transient response when these cells are put in, but a sustained vision for a long time. Even though the retina is often considered to be ‘immune privileged,’ we have found that we can’t ignore cell rejection when trying to transplant stem cells into the eye.”

In the future, Lamba will explore the potential for using drugs that target the specific protein receptor they blocked earlier to improve the outcome of embryonic stem cell-derived retinal transplants,

“We can also potentially identify other small molecules or recombinant proteins to reduce this interleukin 2 receptor gamma activity in the body – even eye-specific immune responses – that might reduce cell rejection. Of course it is not validated yet, but now that we have a target, that is the future of how we can apply this work to humans.”

Who will be the winner?

The Buck Institute study is interesting because it suggests that embryonic stem cell-based transplants combined with immunosuppression could be a promising strategy to improve vision in patients. But it also begs the question of whether the field should focus instead on iPSC-based therapies where a patient’s own stem cells are used to make the transplanted cells. This strategy would side step the immune response and prevent patients from a taking a lifetime of immunosuppressive drugs.

However, I’m not saying that RIKEN’s iPSC-based strategy is necessarily the way to go for treating blindness (at least not yet). It takes a lot of time and money to make iPSC lines and it’s not feasible given our current output to generate iPSC lines for every blind patient.

So, it sounds like a winner in this fight to cure blindness won’t be announced any time soon. In the meantime, both teams need to conduct further preclinical studies before they can move on to testing these treatments in human clinical trials.

Here at CIRM, we’re funding a promising Phase 1 clinical trial sponsored by jCyte for a form of blindness called Retinis Pigmentosa. Based on preliminary results with a small cohort of patient, the treatment seems safe and may even be showing hints of effectiveness in some patients.

Ultimately, more is better. As the number of stem cell clinical trials for blindness grows, the sooner we can find out which therapies work best for which patients.