Stem cell stories that caught our eye: menstrual cycle on a chip, iPS cells from urine, Alpha Stem Cell Clinic Symposium videos

Say hello to EVATAR, a mini female reproductive system on a 3D chip. (Karen Ring)
I was listening to the radio this week in my car and caught snippets of a conversation that mentioned the word “Evatar”. Having tuned in halfway through the story, naturally I thought that the reporters were talking about James Cameron’s sequel to Avatar, and was slightly puzzled about the early press since the sequel isn’t expected to come out until 2020.

I was wrong in my assumption, but not that far off. It turns out that they were actually talking about a cutting edge new technology that generates artificial organs on 3D microfluidic chips. In the case of EVATAR, scientists have developed a functioning mini female reproductive system with all the essential components to recreate the female menstrual cycle. This sounds like science fiction, but it’s real. If you don’t believe me, you can read the publication in the journal Nature Communications.

EVATAR is a 3D organ-on-a-chip representing the female reproductive system. (Photo credit: Woodruff Lab, Northwestern University.)

 The chip consists of small boxes that each house an essential component of the reproductive system including the uterus, fallopian tubes, ovaries, cervix, and vagina. These tissues are generated from human stem cells except for the ovaries which were derived from mouse stem cells. The mini organs are connected to each other by tiny tubes and pumps that simulate blood flow and create a complete reproductive system. By adding specific hormones to this chip, the scientists stimulated the ovaries to produce the hormones estrogen and progesterone and even release an egg.

With EVATAR up and running, scientists are planning to use these personalized devices for various medical purposes including understanding reproductive diseases like endometriosis and testing how drugs affect specific people. The team is also developing a male version of this 3D reproductive chip called ADATAR and plans to study the two models side by side to understand differences in drug metabolism between men and women.

EVATAR is part of a larger project spearheaded by the National Institutes of Health to develop a “body-on-a-chip”. The lead author on the study, Teresa Woodruff from Northwestern University, explained in a news release how scaling down a human body to the size of a small chip that fits in your hand scales up the impact that the technology can have on developing personalized medicine for patients with various diseases.

“If I had your stem cells and created a heart, liver, lung and an ovary, I could test 10 different drugs at 10 different doses on you and say, ‘Here’s the drug that will help your Alzheimer’s or Parkinson’s or diabetes. It’s the ultimate personalized medicine, a model of your body for testing drugs.”

EVATAR has been popular in the press and was picked up by news outlets like NPR, STAT news and Tech Times. You can learn more about this technology by watching the video below provided by Northwestern Medicine.

Abracadabra: Researchers make stem cells from urine (Todd Dubnicoff)
I think one of the reasons the induced pluripotent stem cell (iPSC) technique became a Nobel Prize winning breakthrough, is due to its simplicity. All it takes is a slightly invasive skin biopsy and the addition of a few key factors to reprogram the skin cells into an embryonic stem cell-like state. The method is a game-changer for studying brain development disorders like Down Syndrome. Brain cells from affected individuals are not accessible so deriving these cells from iPSCs is critical in examining the differences between a healthy and Down Syndrome brain.

But skin biopsies are not “slightly invasive” when working with adults or children with an intellectual disability like Down Syndrome. The oversight committees that evaluate the ethics of a proposed human research study often denied such procedures. And even when they are approved, patients or caregivers have often dropped out of studies due to the biopsy method. This sensitive situation has hampered the progress of iPSC-based studies of Down Syndrome.

This week, a research team at Case Western Reserve University School of Medicine reported in STEM CELLS Translational Medicine that they’ve overcome this obstacle with a truly non-invasive procedure: collect cells via urine samples. But wait there’s more. It turns out that iPSCs derived from urine are more stable than their skin biopsy counterparts. The team believes it’s because skin cells, unlike cells found in urine, are exposed to the sunlight’s DNA-damaging UV radiation.

So far the team has banked iPSC lines from ten individuals with Down Syndrome which they will share with other researchers. Team lead Alberto Costa described the importance of these cell lines in a press release:

“Our methods represent a significant improvement in iPSC technology, and should be an important step toward the development of human cell-based platforms that can be used to test new medications designed to improve the quality of life of people with Down syndrome.”

ICYMI the CIRM Alpha Stem Cell Clinic Symposium Talks are Now on YouTube!
Last week, City of Hope hosted a fantastic meeting featuring the efforts of our CIRM Alpha Stem Cell Clinics. It was the second annual symposium and it featured talks from scientists, doctors, patients and advocates about the advancements in stem cell-based clinical trials and the impacts those trials have had on the lives of patients.

We wrote about the symposium earlier this week, but we couldn’t capture all the amazing talks and stories that were shared throughout the day. Luckily, the City of Hope filmed all the talks and they are now available on YouTube. Below are a few that we selected, but be sure to check out the rest on the City of Hope YouTube page.


CIRM President and CEO Randy Mills highlights the goals of the CIRM Alpha Clinics Network and what’s been achieved since its inception in 2014. 


CIRM’s Geoffrey Lomax talks about how the vision of the Alpha Clinics has turned into a reality for patients.

CIRM-funded UC Irvine Scientist, Henry Klassen, talks about his promising stem cell clinical trial for patients with a blinding disease called Retinitis Pigmentosa.

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: stem cell insights into anorexia, Zika infection and bubble baby 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.

Stem cell model identifies new culprit for anorexia.

Eating disorders like anorexia nervosa are often thought to be caused by psychological disturbances or societal pressure. However, research into the genes of anorexia patients suggests that what’s written in your DNA can be associated with an increased vulnerability to having this disorder. But identifying individual genes at fault for a disease this complex has remained mostly out of scientists’ reach, until now.

A CIRM-funded team from the UC San Diego (UCSD) School of Medicine reported this week that they’ve developed a stem cell-based model of anorexia and used it to identify a gene called TACR1, which they believe is associated with an increased likelihood of getting anorexia.

They took skin samples from female patients with anorexia and reprogrammed them into induced pluripotent stem cells (iPSCs). These stem cells contained the genetic information potentially responsible for causing their anorexia. The team matured these iPSCs into brain cells, called neurons, in a dish, and then studied what genes got activated. When they looked at the genes activated by anorexia neurons, they found that TACR1, a gene associated with psychiatric disorders, was switched on higher in anorexia neurons than in healthy neurons. These findings suggest that the TACR1 gene could be an identifier for this disease and a potential target for developing new treatments.

In a UCSD press release, Professor and author on the study, Alysson Muotri, said that they will follow up on their findings by studying stem cell lines derived from a larger group of patients.

Alysson Muotri UC San Diego

“But more to the point, this work helps make that possible. It’s a novel technological advance in the field of eating disorders, which impacts millions of people. These findings transform our ability to study how genetic variations alter brain molecular pathways and cellular networks to change risk of anorexia nervosa — and perhaps our ability to create new therapies.”

Anorexia is a disease that affects 1% of the global population and although therapy can be an effective treatment for some, many do not make a full recovery. Stem cell-based models could prove to be a new method for unlocking new clues into what causes anorexia and what can cure it.

Nature versus Zika, who will win?

Zika virus is no longer dominating the news headlines these days compared to 2015 when large outbreaks of the virus in the Southern hemisphere came to a head. However, the threat of Zika-induced birth defects, like microcephaly to pregnant women and their unborn children is no less real or serious two years later. There are still no effective vaccines or antiviral drugs that prevent Zika infection but scientists are working fast to meet this unmet need.

Speaking of which, scientists at UCLA think they might have a new weapon in the war against Zika. Back in 2013, they reported that a natural compound in the body called 25HC was effective at attacking viruses and prevented human cells from being infected by viruses like HIV, Ebola and Hepatitis C.

When the Zika outbreak hit, they thought that this compound could potentially be effective at preventing Zika infection as well. In their new study published in the journal Immunity, they tested a synthetic version of 25HC in animal and primate models, they found that it protected against infection. They also tested the compound on human brain organoids, or mini brains in a dish made from pluripotent stem cells. Brain organoids are typically susceptible to Zika infection, which causes substantial cell damage, but this was prevented by treatment with 25HC.

Left to right: (1) Zika virus (green) infects and destroys the formation of neurons (pink) in human stem cell-derived brain organoids.  (2) 25HC blocks Zika infection and preserves neuron formation in the organoids. (3) Reduced brain size and structure in a Zika-infected mouse brain. (4) 25HC preserves mouse brain size and structure. Image courtesy of UCLA Stem Cell.

A UCLA news release summarized the impact that this research could have on the prevention of Zika infection,

“The new research highlights the potential use of 25HC to combat Zika virus infection and prevent its devastating outcomes, such as microcephaly. The research team will further study whether 25HC can be modified to be even more effective against Zika and other mosquito-borne viruses.”

Harnessing a naturally made weapon already found in the human body to fight Zika could be an alternative strategy to preventing Zika infection.

Gene therapy in stem cells gives hope to bubble-babies.

Last week, an inspiring and touching story was reported by Erin Allday in the San Francisco Chronicle. She featured Ja’Ceon Golden, a young baby not even 6 months old, who was born into a life of isolation because he lacked a properly functioning immune system. Ja’Ceon had a rare disease called severe combined immunodeficiency (SCID), also known as bubble-baby disease.

 

Ja’Ceon Golden is treated by patient care assistant Grace Deng (center) and pediatric oncology nurse Kat Wienskowski. Photo: Santiago Mejia, The Chronicle.

Babies with SCID lack the body’s immune defenses against infectious diseases and are forced to live in a sterile environment. Without early treatment, SCID babies often die within one year due to recurring infections. Bone marrow transplantation is the most common treatment for SCID, but it’s only effective if the patient has a donor that is a perfect genetic match, which is only possible for about one out of five babies with this disease.

Advances in gene therapy are giving SCID babies like Ja’Ceon hope for safer, more effective cures. The SF Chronicle piece highlights two CIRM-funded clinical trials for SCID run by UCLA in collaboration with UCSF and St. Jude Children’s Research Hospital. In these trials, scientists isolate the bone marrow stem cells from SCID babies, correct the genetic mutation causing SCID in their stem cells, and then transplant them back into the patient to give them a healthy new immune system.

The initial results from these clinical trials are promising and support other findings that gene therapy could be an effective treatment for certain genetic diseases. CIRM’s Senior Science Officer, Sohel Talib, was quoted in the Chronicle piece saying,

“Gene therapy has been shown to work, the efficacy has been shown. And it’s safe. The confidence has come. Now we have to follow it up.”

Ja’Ceon was the first baby treated at the UCSF Benioff Children’s Hospital and so far, he is responding well to the treatment. His great aunt Dannie Hawkins said that it was initially hard for her to enroll Ja’Ceon in this trial because she was a partial genetic match and had the option of donating her own bone-marrow to help save his life. In the end, she decided that his involvement in the trial would “open the door for other kids” to receive this treatment if it worked.

Ja’Ceon Golden plays with patient care assistant Grace Deng in a sterile play area at UCSF Benioff Children’s Hospital.Photo: Santiago Mejia, The Chronicle

It’s brave patients and family members like Ja’Ceon and Dannie that make it possible for research to advance from clinical trials into effective treatments for future patients. We at CIRM are eternally grateful for their strength and the sacrifices they make to participate in these trials.

Stem Cell Stories That Caught Our Eye: Three new ways to target cancer stem cells

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

Targeting cancer stem cells. This week, three studies came out with novel ways for targeting cancer stem cells in different types of cancers. Here’s a brief run-down of this trifecta of cancer stem cell-crushing stories:

Take your vitamins! Scientists in the UK were experimenting on cancer stem cells and comparing natural substances to on-the-market cancer drugs to determine whether any of the natural substances were effective at disrupting the metabolism (the chemical reactions that keep cells alive and functioning) of cancer stem cells. Interestingly, they found that ascorbic acid, which you’ll know as Vitamin C, was ten times better at curbing cancer stem cell growth compared to a cancer drug called 2-DG.

Vitamin C has popped up as an anti-cancer treatment in the past when Nobel Laureate Linus Pauling found that it dramatically reduced the death rate in breast cancer patients. However this current study is the first to show that Vitamin C has a direct effect on cancer stem cells.

In coverage by ScienceDaily, the UK team hinted at plans to test Vitamin C in clinical trials:

“Vitamin C is cheap, natural, non-toxic and readily available so to have it as a potential weapon in the fight against cancer would be a significant step. Our results indicate it is a promising agent for clinical trials, and a as an add-on to more conventional therapies, to prevent tumour recurrence, further disease progression and metastasis.”

 

A gene called ZEB1 determines how aggressive brain tumors are. A team from Cedars-Sinai Medical Center was interested to know how cancer stem cells in aggressive brain tumors called gliomas survive, reproduce and affect patient survival. In a study published in Scientific Reports, they studied the genetic information of over 4000 brain tumor samples and found ZEB1, a gene that regulates tumor growth and is associated with patient survival.

They found that patients with a healthy copy of the ZEB1 gene had a higher survival rate and less aggressive tumors compared to patients that didn’t have ZEB1 or had a mutated version of the gene.

In coverage by ScienceDaily, the senior author on the study explained how their study’s findings will allow for more personalized treatments for patients with glioma based on whether they have ZEB1 or not:

“Patients without the gene in their tumors have more aggressive cancers that act like stem cells by developing into an uncontrollable number of cell types. This new information could help us to measure the mutation in these patients so that we are able to provide a more accurate prognosis and treatment plan.”

 

Beating resistant tumors by squashing cancer stem cells. Our final cancer stem cell story today comes from the UCLA School of Dentistry. This team is studying another type of aggressive cancer called a squamous cell carcinoma that causes tumors in the head and neck. Often these tumors resist treatment and spread to a patient’s lymph nodes, which quickly reduces their survival rate.

The UCLA team thought that maybe pesky cancer stem cells were to blame for the aggressive and resistant nature of these head and neck tumors. In a study published in Cell Stem Cell, they developed a mouse model of head and neck carcinoma and isolated cancer stem cells from the tumors of these mice. When they studied these stem cells, they found that they expressed unique proteins compared to non-cancer cells. These included Bmi1, a well-known stem cell protein, and AP-1, a transcription factor protein that regulates other cancer genes.

At left, head and neck squamous cell carcinoma invasive growth, and at right, cancer stem cells (shown in red) in head and neck squamous cell carcinoma. (Image Demeng Chen and Cun-Yu Wang/UCLA)

After identifying the culprits, the team developed a new combination strategy that targeted the cancer stem cells while also killing off the tumors using chemotherapy drugs.

In a UCLA Newsroom press release, the lead scientist on the study Dr. Cun-Yu Wang explained the importance of their study for the future treatment of cancer and solid tumors:

“This study shows that for the first time, targeting the proliferating tumor mass and dormant cancer stem cells with combination therapy effectively inhibited tumor growth and prevented metastasis compared to monotherapy in mice. Our discovery could be applied to other solid tumors such as breast and colon cancer, which also frequently metastasizes to lymph nodes or distant organs.”

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.”

Stem cells stories that caught our eye: switching cell ID to treat diabetes, AI predicts cell fate, stem cell ALS therapy for Canada

Treating diabetes by changing a cell’s identity. Stem cells are an ideal therapy strategy for treating type 1 diabetes. That’s because the disease is caused by the loss of a very specific cell type: the insulin-producing beta cell in the pancreas. So, several groups are developing treatments that aim to replace the lost cells by transplanting stem cell-derived beta cells grown in the lab. In fact, Viacyte is applying this approach in an ongoing CIRM-funded clinical trial.

In preliminary animal studies published late last week, a Stanford research team has shown another approach may be possible which generates beta cells inside the body instead of relying on cells grown in a petri dish. The CIRM-funded Cell Metabolism report focused on alpha cells, another cell type in pancreas which produces the hormone glucagon.

glucagon

Microscopy of islet cells, round clusters of cells found in the pancreas. The brown stained cells are glucagon-producing alpha cells. Credit: Wikimedia Commons

After eating a meal, insulin is critical for getting blood sugar into your cells for their energy needs. But glucagon is needed to release stored up sugar, or glucose, into your blood when you haven’t eaten for a while. The research team, blocked two genes in mice that are critical for maintaining an alpha cell state. Seven weeks after inhibiting the activity of these genes, the researchers saw that many alpha cells had converted to beta cells, a process called direct reprogramming.

Does the same thing happen in humans? A study of cadaver donors who had been recently diagnosed with diabetes before their death suggests the answer is yes. An analysis of pancreatic tissue samples showed cells that produced both insulin and glucagon, and appeared to be in the process of converting from beta to alpha cells. Further genetic tests showed that diabetes donor cells had lost activity in the two genes that were blocked in the mouse studies.

It turns out that there’s naturally an excess of alpha cells so, as team lead Seung Kim mentioned in a press release, this strategy could pan out:

image-img-620-high

Seung Kim. Credit: Steve Fisch, Stanford University

“This indicates that it might be possible to use targeted methods to block these genes or the signals controlling them in the pancreatic islets of people with diabetes to enhance the proportion of alpha cells that convert into beta cells.”

Using computers to predict cell fate. Deep learning is a cutting-edge area of computer science that uses computer algorithms to perform tasks that border on artificial intelligence. From beating humans in a game of Go to self-driving car technology, deep learning has an exciting range of applications. Now, scientists at Helmholtz Zentrum München in Germany have used deep learning to predict the fate of cells.

170221081734_1_900x600

Using deep learning, computers can predict the fate of these blood stem cells.
Credit: Helmholtz Zentrum München.

The study, published this week in Nature Methods, focused on blood stem cells also called hematopoietic stem cells. These cells live in the bone marrow and give rise to all the different types of blood cells. This process can go awry and lead to deadly disorders like leukemia, so scientists are very interested in exquisitely understanding each step that a blood stem cell takes as it specializes into different cell types.

Researchers can figure out the fate of a blood stem cells by adding tags, which glow with various color, to the cell surface . Under a microscope these colors reveal the cells identity. But this method is always after the fact. There no way to look at a cell and predict what type of cell it is turning into. In this study, the team filmed the cells under a microscope as they transformed into different cell types. The deep learning algorithm processed the patterns in the cells and developed cell fate predictions. Now, compared to the typical method using the glowing tags, the researchers knew the eventual cell fates much sooner. The team lead, Carsten Marr, explained how this new technology could help their research:

“Since we now know which cells will develop in which way, we can isolate them earlier than before and examine how they differ at a molecular level. We want to use this information to understand how the choices are made for particular developmental traits.”

Stem cell therapy for ALS seeking approval in Canada. (Karen Ring) Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease that kills off the nerve cells responsible for controlling muscle movement. Patients with ALS suffer from muscle weakness, difficulty in speaking, and eventually breathing. There is no cure for ALS and the average life expectancy after diagnosis is just 2 – 5 years. But companies are pursuing stem cell-based therapies in clinical trials as promising treatment options.

One company in particular, BrainStorm Cell Therapeutics based in the US and Israel, is testing a mesenchymal stem cell-based therapy called NurOwn in ALS patients in clinical trials. In their Phase 2 trials, they observed clinical improvements in slowing down the rate of disease progression following the stem cell treatment.

In a recent update from our friends at the Signals Blog, BrainStorm has announced that it is seeking regulatory approval of its NurOwn treatment for ALS patients in Canada. They will be working with the Centre for Commercialization of Regenerative Medicine (CCRM) to apply for a special regulatory approval pathway with Health Canada, the Canadian government department responsible for national public health.

In a press release, BrainStorm CEO Chaim Lebovits, highlighted this new partnership and his company’s mission to gain regulatory approval for their ALS treatment:

“We are pleased to partner with CCRM as we continue our efforts to develop and make NurOwn available commercially to patients with ALS as quickly as possible. We look forward to discussing with Health Canada staff the results of our ALS clinical program to date, which we believe shows compelling evidence of safety and efficacy and may qualify for rapid review under Canada’s regulatory guidelines for drugs to treat serious or life-threatening conditions.”

Stacey Johnson who wrote the Signals Blog piece on this story explained that while BrainStorm is not starting a clinical trial for ALS in Canada, there will be significant benefits if its treatment is approved.

“If BrainStorm qualifies for this pathway and its market authorization request is successful, it is possible that NurOwn could be available for patients in Canada by early 2018.  True access to improved treatments for Canadian ALS patients would be a great outcome and something we are all hoping for.”

CIRM is also funding stem cell-based therapies in clinical trials for ALS. Just yesterday our Board awarded Cedars-Sinai $6.15 million dollars to conduct a Phase 1 trial for ALS patients that will use “cells called astrocytes that have been specially re-engineered to secrete proteins that can help repair and replace the cells damaged by the disease.” You can read more about this new trial in our latest news release.

Stem cell stories that caught our eye: drug safety for heart cells, worms hijack plant stem cells & battling esophageal cancer

Devising a drug safety measuring stick in stem cell-derived heart muscle cells
One of the mantras in the drug development business is “fail early”. That’s because most of the costs of getting a therapy to market occur at the later stages when an experimental treatment is tested in clinical trials in people. So, it’s best for a company’s bottom line and, more importantly, for patient safety to figure out sooner rather than later if a therapy has dangerous toxic side effects.

Researchers at Stanford reported this week in Science Translational Medicine on a method they devised that could help weed out cancer drugs with toxic effects on the heart before the treatment is tested in people.

In the lab, the team grew beating heart muscle cells, or cardiomyocytes, from induced pluripotent stem cells derived from both healthy volunteers and kidney cancer patients. A set of cancer drugs called tyrosine kinase inhibitors which are known to have a range of serious side effects on the heart, were added to the cells. The effect of the drugs on the heart cell function were measured with several different tests which the scientists combined into a single “safety index”.

roundup_wu

A single human induced pluripotent stem cell-derived cardiomyocyte. Cells such as these were used to assess tyrosine kinase inhibitors for cardiotoxicity in a high-throughput fashion. Credit: Dr. Arun Sharma at Dr. Joseph Wu’s laboratory at Stanford University

They found that the drugs previously shown to have toxic effects on patients’ hearts had the worst safety index values in the current study. And because these cells were in a lab dish and not in a person’s heart, the team was able to carefully examine cell activity and discovered that the toxic effects of three drugs could be alleviated by also adding insulin to the cells.

As lead author Joseph Wu, director of the Stanford Cardiovascular Institute, mentions in a press release, the development of this drug safety index could provide a powerful means to streamline the drug development process and make the drugs safer:

“This type of study represents a critical step forward from the usual process running from initial drug discovery and clinical trials in human patients. It will help pharmaceutical companies better focus their efforts on developing safer drugs, and it will provide patients more effective drugs with fewer side effects”

Worm feeds off of plants by taking control of their stem cells
In what sounds like a bizarre mashup of a vampire movie with a gardening show, a study reported this week pinpoints how worms infiltrate plants by commandeering the plants’ own stem cells. Cyst nematodes are microscopic roundworms that invade and kill soybean plants by sucking out their nutrients. This problem isn’t a trivial matter since nematodes wreak billions of dollars of damage to the world’s soybean crops each year. So, it’s not surprising that researchers want to understand how exactly these critters attack the plants.

nematode-feeding-site

A nematode, the oblong object on the left, activates the vascular stem cell pathway in the developing nematode feeding site on a plant root. Credit: Xiaoli Guo, University of Missouri

Previous studies by Melissa Goellner Mitchum, a professor at the University of Missouri, had shown that the nematodes release protein fragments, called peptides, near a plant’s roots that help divert the flow of plant nutrients to the worm.

“These parasites damage root systems by creating a unique feeding cell within the roots of their hosts and leeching nutrients out of the soybean plant. This can lead to stunting, wilting and yield loss for the plant,” Mitchum explained in a press release.

In the current PLOS Pathogens study, Mitchum’s team identified another peptide produced by the nematode that is identical to a plant peptide that instructs stem cells to form the plant equivalent of blood vessels. This devious mimicking of the plant peptides is what allows the nematode to trick the plant stem cells into building vessels that reroute the plants’ nutrients directly to the worm.

Mitchum described the big picture implications of this fascinating discovery:

“Understanding how plant-parasitic nematodes modulate host plants to their own benefit is a crucial step in helping to create pest-resistant plants. If we can block those peptides and the pathways nematodes use to overtake the soybean plant, then we can enhance resistance for this very valuable global food source.”

Finding vulnerabilities in treatment-resistant esophageal cancer stem cells

diagram_showing_internal_radiotherapy_for_cancer_of_the_oesophagus_cruk_162-svg

Illustration of radiation therapy for esophageal cancer.
Credit: Cancer Research UK

The incidence of esophageal cancer has increased more than any other disease over the past 30 years. And while some patients respond well to chemotherapy and radiation treatment, most do not because the cancer becomes resistant to these treatments.

Focusing on cancer stem cells, researchers at Trinity College Dublin have identified an approach that may overcome treatment resistance.

Within tumors are thought to lie cancer stem cells that, just like stem cells, have the ability to multiply indefinitely. Even though they make up a small portion of a tumor, in some patients the cancer stem cells evade the initial rounds of treatment and are responsible for the return of the cancer which is often more aggressive. Currently, there’s no effective way to figure out how well a patient with esophageal cancer will response to treatment.

In the current study published in Oncotarget, the researchers found that a genetic molecule called miR-17 was much less abundant in the esophageal cancer stem cells. In fact, the cancer stem cells with the lowest levels of miR-17, were the most resistant to radiation therapy. The researchers went on to show that adding back miR-17 to the highly resistant cells made them sensitive again to the radiation. Niamh Lynam-Lennon, the study’s first author, explained in a press release that these results could have direct clinical applications:

“Going forward, we could use synthetic miR-17 as an addition to radiotherapy to enhance its effectiveness in patients. This is a real possibility as a number of other synthetic miR-molecules are currently in clinical trials for treating other diseases.”

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

Stories that caught our eye: new target for killing leukemia cancer stem cells and stem cell vesicles halt glaucoma

New stem cell target for acute myeloid leukemia (Karen Ring).  A new treatment for acute myeloid leukemia, a type of blood cancer that turns bone marrow stem cells cancerous, could be in the works in the form of a cancer stem cell destroying antibody.

13192

Acute Myeloid Leukemia (Credit: Medscape)

Scientists from the NYU Langone Medical Center and the Memorial Sloan Kettering Cancer Center identified a protein called CD99 that appears more abundantly on the surface of abnormal blood cancer stem cells compared to healthy blood stem cells. They developed an antibody that specifically recognizes and kills the CD99 wielding cancer stem cells while leaving the healthy blood stem cells unharmed.

The CD99 antibody was effective at killing human AML stem cells in a dish and in mice that were transplanted with the same type of cancer stem cells. Further studies revealed that the CD99 antibody when attached to the surface of cancer stem cells, sets off a cascade of enzyme activity that causes these cells to die. These findings suggest that cancer stem cells express more CD99 as a protective mechanism against cell death.

In an interview with Genetic Engineering and Biotechnology News, Chris Park, senior author on the Science Translational Medicine study, explained the importance of their work:

“Our findings not only identify a new molecule expressed on stem cells that drive these human malignancies, but we also show that antibodies against this target can directly kill human AML stem cells. While we still have important details to work out, CD99 is likely to be an exploitable therapeutic target for most AML and MDS patients, and we are working urgently to finalize a therapy for human testing.”

While this work is still in the early stages, Dr. Park stressed that his team is actively working to translate their CD99 antibody therapy into clinical trials.

“With the appropriate support, we believe we can rapidly determine the best antibodies for use in patients, produce them at the quality needed to verify our results, and apply for permission to begin clinical trials.”

 

Peculiar stem cell function may help treat blindness (Todd Dubnicoff). Scientists at the National Eye Institute (NEI) have uncovered a novel function that stem cells use to carry out their healing powers and it may lead to therapies for glaucoma, the leading cause of blindness in United States. Reporting this week in Stem Cells Translational Medicine, the researchers show that stem cells send out regenerative signals by shedding tiny vesicles called exosomes. Once thought to be merely a garbage disposal system, exosomes are now recognized as an important means of communication between cells. As they bud off from the cells, the exosomes carry proteins and genetic material that can be absorbed by other cells.

Microscopy image shows exosomes (green) surrounding retinal ganglion cells (orange and yellow). Credit: Ben Mead

Microscopy image shows exosomes (green) surrounding retinal ganglion cells (orange and yellow). Credit: Ben Mead

The researchers at NEI isolated exosomes from bone marrow stem cells and injected them into the eyes of rats with glaucoma symptoms. Without treatment, these animals lose about 90 percent of their retinal ganglion cells, the cells responsible for forming the optic nerve and for sending visual information to the brain. With the exosome treatment, the rats only lost a third of the retinal ganglion cells. The team determined that microRNAs – small genetic molecules that can inhibit gene activity – inside the exosome were responsible for the effect.

Exosomes have some big advantages over stem cells when comes to developing and manufacturing therapies which lead author Ben Mead explains in a press release picked up by Eureka Alert:

“Exosomes can be purified, stored and precisely dosed in ways that stem cells cannot.”

We’ll definitely keep our eyes on this development. If these glaucoma studies continue to look promising it stands to reason that there would be exosome applications in many other diseases.

Stories that caught our eye: $20.5 million in new CIRM discovery awards, sickle cell disease cell bank, iPSC insights

CIRM Board launches a new voyage of Discovery (Kevin McCormack).
Basic or early stage research is the Rodney Dangerfield of science; it rarely gets the respect it deserves. Yesterday, the CIRM governing Board showed that it not only respects this research, but also values its role in laying the foundation for everything that follows.

The CIRM Board approved 11 projects, investing more than $20.5 million in our Discovery Quest, early stage research program. Those include programs using gene editing techniques to develop a cure for a rare but fatal childhood disease, finding a new approach to slowing down the progress of Parkinson’s disease, and developing a treatment for the Zika virus.

Zika_EM_CDC_20538 copy.jpg

Electron micrograph of Zika virus (red circles). Image: CDC/Cynthia Goldsmith

The goal of the Discovery Quest program is to identify and explore promising new stem cell therapies or technologies to improve patient care.

In a news release Randy Mills, CIRM’s President & CEO, said we hope this program will create a pipeline of projects that will ultimately lead to clinical trials:

“At CIRM we never underestimate the importance of early stage scientific research; it is the birth place of groundbreaking discoveries. We hope these Quest awards will not only help these incredibly creative researchers deepen our understanding of several different diseases, but also lead to new approaches on how best to use stem cells to develop treatments.”

Creating the world’s largest stem cell bank for sickle cell disease (Karen Ring).
People typically visit the bank to deposit or take out cash, but with advancements in scientific research, people could soon be visiting banks to receive life-saving stem cell treatments. One of these banks is already in the works. Scientists at the Center for Regenerative Medicine (CReM) at Boston Medical Center are attempting to generate the world’s largest stem cell bank focused specifically on sickle cell disease (SCD), a rare genetic blood disorder that causes red blood cells to take on an abnormal shape and can cause intense pain and severe organ damage in patients.

To set up their bank, the team is collecting blood samples from SCD patients with diverse ethnic backgrounds and making induced pluripotent stem cells (iPSCs) from these samples. These patient stem cell lines will be used to unravel new clues into why this disease occurs and to develop new potential treatments for SCD. More details about this new SCD iPSC bank can be found in the latest edition of the journal Stem Cell Reports.

crem_boston_130996_web

Gustavo Mostoslavsky, M.D., PH.D., Martin Steinberg, M.D., George Murphy PH.D.
Photo: Boston Medical Center

In a news release, CReM co-founder and Professor, Gustavo Mostoslavsky, touched on the future importance of their new stem cell bank:

“In addition to the library, we’ve designed and are using gene editing tools to correct the sickle hemoglobin mutation using the stem cell lines. When coupled with corrected sickle cell disease specific iPSCs, these tools could one day provide a functional cure for the disorder.”

For researchers interested in using these new stem cell lines, CReM is making them available to researchers around the world as part of the NIH’s NextGen Consortium study.

DNA deep dive reveals ways to increase iPSC efficiency (Todd Dubnicoff)
Though the induced pluripotent stem (iPS) cell technique was first described ten years ago, many researchers continue to poke, prod and tinker with the method which reprograms an adult cell, often from skin, into an embryonic stem cell-like state which can specialize into any cell type in the body. Though this breakthrough in stem cell research is helping scientists better understand human disease and develop patient-specific therapies, the technique is hampered by its low efficiency and consistency.

This week, a CIRM-funded study from UCLA reports new insights into the molecular changes that occur during reprogramming that may help pave the way toward better iPS cell methods. The study, published in Cell, examined the changes in DNA during the reprogramming process.

first-and-senior-authors-in-the-lab_800-x-533

Senior authors Kathrin Plath and Jason Ernst and first authors Petko Fiziev and Constantinos Chronis.
Photo: UCLA

In a skin cell, the genes necessary for embryonic stem cell-like, or pluripotent, characteristics are all turned off. One way this shut down in gene activity occurs is through tight coiling of the DNA where the pluripotent genes are located. This physically blocks proteins called transcriptions factors from binding the DNA and activating those pluripotent genes within skin cells. On the other hand, regions of DNA carrying skin-related genes are loosely coiled, so that transcription factors can access the DNA and turn on those genes.

The iPS cell technique works by artificially adding four pluripotent transcriptions factors into skin cells which leads to changes in DNA coiling such that skin-specific genes are turned off and pluripotent genes are turned on. The UCLA team carefully mapped the areas where the transcription factors are binding to DNA during the reprogramming process. They found that the shut down of the skin genes and activation of the pluripotent genes occurs at the same time. The team also found that three of the four iPS cell factors must physically interact with each other to locate and activate the areas of DNA that are responsible for reprogramming.

Using the findings from those experiments, the team was able to identify a fifth transcription factor that helps shut down the skin-specific gene more effectively and, in turn, saw a hundred-fold increase in reprogramming efficiency. These results promise to help the researchers fine-tune the iPS cell technique and make its clinical use more practical.