Stem cell stories that caught our eye: multiple sclerosis, virus genes in embryos and preventing cancer’s spread to the brain

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.

Drugs activate brain stem cells in MS. We have frequently written that in some situations our own stem cells may do a better job at repairing the body than transplanted cells. A team at Case Western in Cleveland has done just that with lab and animal models of Multiple Sclerosis (MS). Even better, they did it with drugs that are already approved for other uses.

They used a steroid, clobetasol, and an antifungal, miconazole, to get a type of stem cell found in the brain to more effectively produce the myelin sheets that protect our nerves and that get destroyed in MS. But in a story in Science Blog the researchers cautioned that patients should not go ask a doctor to inject those drugs. They are currently used only as topical agents on the skin and no one knows what they would do internally in people.

“Off-label use of the current forms of these drugs is more likely to increase other health concerns than alleviate multiple sclerosis symptoms. We are working tirelessly to ready a safe and effective drug for clinical use,” said Paul Tesar who led the study.”

Specifically, the team worked with stem cells called oligodendrocyte progenitor cells. Growing them in the lab they tested hundreds of approved drugs to see if any would nudge those cells into producing myelin. They found these two and tested them in a mouse model of MS and saw improved function in the mice. They are now looking to test other drugs hoping to find one safe for internal use in humans.

Viral genes active in early embryos. Virus genes, mostly left over from infections of our ancestors thousands of years ago, make up some eight percent of the genetic material in our chromosomes. In general those genes just sit there and don’t do anything. But a CIRM funded team at Stanford has found that in the early days of embryo development some of them become quite active.

In fact, they seem to commandeer the growing embryo’s cellular machinery to produce whole virus particles that the researchers detected in the interior of the cells. What they could not determine is whether that activity is benign or somehow directs the development of the embryo—or might be the virus reasserting its parasitic ways.

“It’s both fascinating and a little creepy,” said Joanna Wysocka, the senior author on the study that appeared this week in Nature. “We’ve discovered that a specific class of viruses that invaded the human genome during recent evolution becomes reactivated in the early development of the human embryo, leading to the presence of viral-like particles and proteins in the human cells.”

In the press release, Stanford’s Krista Conger does a nice job of laying out some of the prior research about the origins and nature of all the viral genes hidden amongst our DNA. The release, picked up by HealthCanal makes it clear the finding raises more questions than it provides answers. Edward Grow, the graduate student who was first author on the paper put it this way:

“Does the virus selfishly benefit by switching itself on in these early embryonic cells? Or is the embryo instead commandeering the viral proteins to protect itself? Can they both benefit? That’s possible, but we don’t really know.”

Stem cells with multiple genetic tricks fight cancer. Breast cancer wreaks the most havoc when it spreads and about a third of the time it spreads to the brain. To fight that insidious spread a team a Massachusetts General Hospital and the Harvard Stem Cell Institute has rigged nerve stem cells with multiple genetic tricks to prevent breast cancer cells from growing after they get to the brain.

Certain types of nerve stem cells are naturally attracted to tumors. So the team led by Khalid Shah genetically manipulated those stem cells to express a gene called TRAIL. That gene produces a protein that activates a receptor on the surface of cancer cells that causes them to self-destruct. Then to make sure those stem cells did not stick around and multiply when they are no longer needed, the researchers added another gene that made them susceptible to a common antiviral drug. That drug could be given once the cells had done their work of delivering the suicide note to the cancer cells and the stem cells themselves would then be eliminated.

A press release on the work from MGH was picked up by ScienceNewsline and quoted Shah on the significance of the findings:

“Our results are the first to provide insight into ways of targeting brain metastases with stem-cell-directed molecules that specifically induce the death of tumor cells and then eliminating the therapeutic stem cells.”

In order to measure their results the team started with yet another genetic trick. They wanted to make sure the loaded stem cells were getting to the tumors. So, before they injected breast cancer cells into the carotid arteries in the necks of mice, they modified the cells so that they would express fluorescent markers. That glow could be tracked allowing the researchers to monitor the disappearance of the cancer cells.

This mouse work is obviously many steps away from use in humans, but it provides an ingenious path to follow.

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