Stem Cell Stories that Caught our Eye: Gene Rx, New and Rejuvenated Blood Stem Cells and Budget Cuts

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.

Tinkering with stem cell genes safe. Research at the Salk Institute provides some reassurance that using gene-editing techniques to correct disease-causing mutations in stem cells is safe. This type of intervention aims to give people a corrected version of a gene that can produce a functional protein to replace the bad one they were born with, such as the hemoglobin gene in sickle cell disease. The CIRM-funded Salk team made gene corrections with both of the two most common gene-editing techniques: using a virus to carry the correct gene into the cell, and using an enzyme to cut and splice the genes. The fear, the lead researcher said in Space Daily, has been that this gene manipulation would cause unwanted mutations. Instead the team found that the very small number of mutations in the edited cells did not exceed the number in normal cells growing in the lab for the same length of time.

Blood cells

This is great news for CIRM, since eight of our Disease Teams—all of which have the goal of moving therapies into the clinic—use gene modification techniques. These include efforts to correct the genetic mutation that causes sickle cell disease and beta thalassemia.

Interview with Nobelist on stem cell potential. The Raw Story ran an interview with Nobel Laureate Martin Evans about the field he helped to create when he first isolated mouse embryonic stem cells in 1981. He won the Nobel in 2007 for later work in which he used embryonic stem cells to create specific gene modifications in mice. He said we are “just scraping the surface” in unlocking the potential of stem cells to change medicine. He also addresses various aspects of reprogramming cells to become different types of tissue and provides a bit of advice to young scientists: “You should not believe in all that you read.”

Keep your blood stem cells acting young. Blood stem cells, like most of the adult stem cells in our various tissues, become less adept at doing their job of replenishing our tissues as we age. A team at New York’s Mount Sinai has fingered the decrease of a specific protein in older stem cells as the culprit. That protein, SIRT1, was not a surprise as it has been implicated in other aging research. When laboratory animals eat a severely calorie restricted diet and live longer, SIRT1 is active at a higher than normal level. So, it makes some sense that low levels of SIRT1 would be associated with conditions of aging. The team now wants to see if increasing SIRT1 levels can put the kick of youth back into older blood stem cells. The web portal Hospital Newspaper ran a story on the research that the team published in Stem Cell Reports.

Or use a new way to create blood cells. If you can’t get your own blood stem cells to behave like vigorous youthful cells another option is to get some new one. The problem is many folks cannot find a matching donor and previous attempts to grow them from earlier stage stem cells have not worked. Using either embryonic or reprogrammed iPS type stem cells to try to grow large quantities of blood-forming stem cells has always resulted in immature cells that cannot make all the blood cells and don’t readily take up residence—engraft—in the patient. Researchers at Cornell Medical College may have solved this problem by growing the stem cells in a more natural environment. They grew them in a bed of cells like those that would have surrounded them in blood vessels in a developing fetus. The resulting cells engrafted in mice and produced nearly all the components of blood. They had a few lingering problems with creating the immune system’s T cells, but got much closer than previous work. Device Space picked up the medical school’s press release.

This goal of creating fully functional blood stem cells is sufficiently important but vexing to the research community that CIRM organized an international workshop on the topic. You can read the resulting whitepaper “Breaking the Bottleneck.”

Donors needed to power discovery. With federal support for research shrinking many institutions are relying more and more on donors to fund the research that leads to discoveries and eventually therapies. The New York based web publication Capital Playbook painted a picture of the deficit citing a 22 percent reduction in the inflation-adjusted budget for the National Institutes of Health since 2003. It goes on to quote senior scientists fearing the loss of a generation of scientists. A great comment came from my friend and former colleague David Scadden, co-director of the Harvard Stem Cell Institute. “They are seeing their senior mentors spending more and more time writing grants and going hat in hand. That’s not a good way to inspire the best and brightest.”

Don Gibbons

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