A Little Acid Turns Mouse Blood Into Brain, Heart And Stem Cells
Back in 1958, a young biologist at Cornell University made a stunning discovery.
He took a single cell from a carrot and then mixed it with some coconut milk. Days went by and the cell started dividing. Little roots formed. Stems started growing. Eventually, a whole new carrot plant rose up from the single cell.
Imagine if you could perform a similar feat with animal cells, even human cells.
A team of Japanese biologists say they've taken a big step toward doing just that, at least in mice. Instead of using coconut milk, though, the magic ingredient is something akin to lemon juice.
Biologist Haruko Obokata and her colleagues at the RIKEN Center for Developmental Biology say they've figured out a fast, easy way to make the most powerful cells in the world — embryonic stem cells — from just one blood cell.
The trick? Put white blood cells from a baby mouse in a mild acid solution, Obokata and her team report Wednesday in the journal Nature. Eventually a few stem cells emerge that can turn into any other cell in the body — skin, heart, liver or neurons, you name it.
For decades, scientists have been searching for easy ways to make human embryonic stem cells. These cells hold great potential for treating diseases such as Alzheimer's, Parkinson's, heart disease and diabetes.
But for a long time, human stem cells were essentially off limits for researchers because the only way to get them was by destroying human embryos.
Then in 2007, another team of scientists at the RIKEN center figured out a way to make human stem cells from skin and blood by manipulating the cell's genes.
That discovery won the team the Nobel Prize in 2012 and opened a whole new avenue for exploring the power of stem cells. But that process has come with its own set of problems.
"It's quite messy, and we don't really understand how it works," biochemist Austin Smith of the University of Cambridge tells NPR's Rob Stein.
In contrast, Smith says, the method developed by Obokata and colleagues, if it pans out, is straightforward and doesn't involve any manipulation inside the cell, only a small change in the cell's environment.
Obokata and her team tested a whole range of treatments in the hopes of creating stem cells, including starving the blood cells, heating them up and even squeezing them through a thin pipette.
What worked the best was simply putting the blood cells in a mild acid for about 30 minutes. The pH of the solution was about 5.7, or a little more acidic than milk. A few days later, the cells stopped acting like blood and started behaving like stem cells.
When the researchers injected the cells into a mouse embryo, the cells acted just like other stem cells: They created all the organs needed for an adult mouse. The team named the cells stimulus-triggered acquisition of pluripotency, or STAP.
"It seems like a new paradigm," says Smith, who wasn't involved with the study. "The method could have many applications, but it really depends on finding out if and how we can extend this [method] in humans."
The researchers don't know whether the method works with blood from adult mice. So far, all of the experiments have used cells taken from infant mice just 1 week old.
"The cells are only a few days old," Smith says. "But we need to know if it works with adult cells and in human cells." That would be essential if the cells are to be used for medical treatments.
And of course, even if the method does work with human cells, there's still a long, long way to go before the cells could be tested in humans.
STEVE INSKEEP, HOST:
Scientists are reporting what may be a big advance in stem cell research. Researchers believe they found a quicker, easier and less controversial way to make stem cells. NPR's Rob Stein reports the news is stirring excitement, surprise and questions in the scientific world.
ROB STEIN, BYLINE: Human embryos contain cells that have the ability to become almost any kind of tissue in the body. They're called stem cells, and the great hope is that someday, they could be used to cure lots of diseases. Charles Vacanti of the Brigham and Women's Hospital in Boston says that includes Alzheimer's, Parkinson's, diabetes.
CHARLES VACANTI: There are many, many diseases that you could potentially cure if you put in the proper cells in the proper location and they function normally.
STEIN: But human embryos have to be destroyed to get these cells, which makes them extremely controversial. So, scientists have been trying to find other ways to make stem cells, and they've been able to do that. They've tinkered with the genes of mature cells and got them to morph back into embryo-like cells. But those cells may have their own problems.
VACANTI: People have suggested that you are more prone to have - develop cancer. Is that true? Possibly.
STEIN: But Vacanti and his colleagues had another idea: Maybe they could make stem cells by mimicking what happens when the body naturally repairs itself.
VACANTI: You know, if you're walking down the street and you fall down and bruise your leg, you know, if you're punched in the eye - wherever you're injured - is that the mature cells are actually reverting back to a stem cell to now repair the injured tissue.
STEIN: So, Vacanti teamed up with some Japanese researchers to see if they could make mature cells turn back into stem cells in the laboratory. The scientists took cells from newborn mice and subjected them to the same kinds of stresses that occur in the body during an injury. For example, they exposed the cells to increased levels of acidity.
VACANTI: We found that if we injured them, almost to the point of dying, but not quite to the point of dying, the cells would revert back to a stem cell state.
STEIN: A stem cell state very much like embryonic stem cells. Then they showed they could use these cells to create virtually every kind of tissue in the body. They went even further. They used these cells to create complete mouse embryos.
VACANTI: It demonstrates that you have the ability to make perfect embryonic stem cells that can then turn into a perfect copy of your own cells.
STEIN: Other scientists were blown away by the research, which was described in two papers in this week's issue of the journal Nature.
GEORGE DALEY: Wow. Yeah.
STEIN: That's George Daley, a leading stem cell scientist at Harvard who was not involved in the research.
DALEY: I mean, I cannot remember reading a paper and feeling so amazed and perplexed at the same time. I mean, it's truly a startling result.
STEIN: It's perplexing, because it raises fundamental questions about how cells really work. Scientists had no idea that our bodies could turn back the clock on cells on their own.
DALEY: This is going to open up whole new ways of thinking about cellular alchemy.
STEIN: And it's startling because it seems to offer a way to make stem cells that's really easy and really fast.
DALEY: The potential is limitless.
STEIN: But Daley and others caution that there's still lots more research that needs to be done to confirm the findings and answer some big questions. Austin Smith is at the University of Cambridge.
AUSTIN SMITH: So, we need to know if this works with adult cells, and then we need to know if it works in human cells, if you're thinking it could be important for some medical purpose.
STEIN: Vacanti says he's already started experiments to see if this works with human cells the way it does with mice, and that he's already got some early results that look very promising. Rob Stein, NPR News. Transcript provided by NPR, Copyright NPR.