Stem cell stories that caught our eye: need for mature fat, Down syndrome, autism and those sweet pup faces

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.

Embryonic stem cells and that sweet puppy face. Could altered stem cells give our pups those floppy ears and adorable faces? Research from Humboldt University in Berlin suggests that is the case. They speculate that when people began to domesticate wild animals they were unwittingly breeding for smaller adrenal glands that are responsible for the “fight-or-flight” syndrome. But those glands arise from a group of stem cells in the developing embryo, the neural crest, that is also responsible for many other aspects of the animal including parts of the skull and the ears.

Annika, a member of the author's "pack," shows the floppy ears and narrow face of domestication. The seat on the furniture could be another clue.

Annika, a member of the author’s “pack,” shows the floppy ears and narrow face of domestication. The seat on the furniture could be another clue.

Researchers have noted since Darwin’s time that these signs of “domestication syndrome” with its floppy ears and narrow faces carry across a broad range of domestic animals. The German team said that the genetic alterations of neural crest stem cells could explain this “hodge-podge of traits.”

The research was published in the journal Genetics and got wide pick up with a fun piece on Mashable and a bit more detail about the science in Pacific Standard Magazine.

Stress might make fat go rogue. It is not something dieters will want to hear, but in order to stay healthy your fat stem cells need to mature into adult fat tissue. When they don’t fat can accumulate at high levels in the bloodstream and within existing cells. A team at Boston University suggests that stress plays a role in how the body processes fat by inhibiting the maturation of fat stem cells. They identified two proteins that act as relay switches to regulate the fat stem cells. That signaling pathway now becomes a target for discovering drugs that might improve our handling of fat, even in times of stress. The team published their work in the Journal of Biological Chemistry and HealthCanal picked up the university’s press release.

Support cells linked to Down syndrome. CIRM-funded researchers at the University of California, Davis have found that the errors in nerve development in Down syndrome may be caused by abnormal functioning of the cells that are supposed to support them, the glial cells. The team started by reprogramming skin cell samples from people with Down syndrome into iPS type stem cells. They then matured those cells in two batches, one into neurons and one into glial cells. The nerves did not seem different from normal nerves but the glial cells produced an abnormally high level of a particular protein. When they mixed the two cell types together, that protein appeared to kill off part of the nerves.

What is intriguing, when they treated the mixed cells with a simple antibiotic the nerve damage did not occur. If the protein only has its negative impact on the developing brain, the finding opens up the possibility of preventive treatment for women who find their fetus has the third chromosome distinctive of Down syndrome. The researchers published their findings in Nature Communication and Science Daily ran a story on the work.

Pros and cons of the large autism trial. Using stem cells to try to treat autism provokes a lot of raw emotion in our field. I frequently field questions from desperate mothers wanting to know where they can take the umbilical cord stem cells they have stored in a freezer to treat their child with autism. I tell them about some of the controversies about this treatment and the need for more data before we know how to use the cells right, if there is any chance they can help at all. The Simons Foundation Autism Research Initiative published a well-balanced analysis of the first large clinical trial trying to answer those questions.

The piece has a skeptic rightfully noting that the type of stem cells in cord blood cannot make replacement cells for the poorly functioning nerve cells in people with autism. It also discusses the possibility that those stem cells might stimulate the person’s own cells to make some of the needed repairs. The trial, which will randomly assign patients to stem cell therapy or no therapy, is being led by Duke University’s Joanne Kurtzenburg, who is described by one outside expert as “the right person to do this.” She is a well-known leader in the field and I would love to have some data to share with parents.

CIRM hosted a group of international experts in autism to look at ways stem cells could foster therapies in autism that produced this report. One of the main suggestions was to use iPS type stem cells to model the disease as shown in this video.

Don Gibbons

What was Old is New Again: Scientists Transplant Brain Cells into Aged Mice and Reverse Memory Loss

Alzheimer’s disease starts with small, almost imperceptible steps. And then it builds. Sometimes slowly over a period of decades, other times more quickly—in just a matter of years. But no matter the speed of progression, the end outcome is always the same.

Transplanted cells (shown in green) in the hippocampus, 3 months after transplantation.  Cell nuclei are labeled in blue.  [Credit: Leslie Tong and Yadong Huang/Gladstone Institutes]

Transplanted cells (shown in green) in the hippocampus, 3 months after transplantation. Cell nuclei are labeled in blue. [Credit: Leslie Tong and Yadong Huang/Gladstone Institutes]

The sixth leading cause of death in the United State, Alzheimer’s develops as brain cells, or neurons, are destroyed over time. The hippocampus, the brain’s memory center, is the hardest hit, which is why memory loss is the single most common—and most devastating—symptom of the disease.

As a result, scientists have looked to the field of regenerative medicine to replace the vital cells lost to Alzheimer’s. And now, researchers at the Gladstone Institutes in San Francisco have made an important step towards that goal.

Reporting in the latest issue of the Journal of Neuroscience, researchers in the laboratory of Dr. Yadong Huang have successful transplanted early-stage brain cells, called “neuron progenitor cells,” into aged mice that have been modified to mimic Alzheimer’s symptoms. And after doing so, what they saw was extraordinary.

Not only did the cells survive the transplantation—a feat in and of itself—they began to grow and integrate into the molecular circuitry of the brain. And that’s when they noticed changes to the animals’ behavior.

These mice, whose age corresponded to humans in late-stage adulthood, were living with physical signs of memory loss. But after the cell transplants, the team saw signs that memory and learning were restored.

Leslie Tong, a graduate student at Gladstone and the University of California, San Francisco and the paper’s first author, elaborated on the importance of these findings in a news release:

“Working with older animals can be challenging from a technical standpoint, and it was amazing that the cells not only survived but affected activity and behavior.”

For a brain to function normally, there should be a balance between two types of neurons: ‘excitatory’ neurons, that act as the brain’s gas pedal, and ‘inhibitory’ neurons that serve as the brake. If this balance between these two cell types gets thrown out of whack, normal function is disrupted—and cells, especially the inhibitory neurons, degrade and die. Combined with other factors, such as genetic risk and the buildup of toxic proteins—this imbalance plays a key role in the dysfunction that eventually leads to Alzheimer’s.

The success of this treatment not only reveals the importance of maintaining this balance in memory and learning, but is also proof of concept that if neurons are lost—they can in principle be replaced.

Huang is particularly excited about the therapeutic potential of these findings. As he stated in the same news release:

“The fact that we see a functional integration of these cells into the hippocampal circuitry and a…rescue of learning and memory deficits in an aged model of Alzheimer’s disease is very exciting.”

This study, which was supported in part by CIRM, points towards several possible therapeutic strategies that could one day help human brains ravaged by Alzheimer’s regrow the cells they’ve lost—and repair the damage to learning and memory that today remains irreparable. According to Huang:

“This study tells us that if there is any way we can enhance inhibitory neuron function in the hippocampus, like through the development of small molecule compounds, it may be beneficial for Alzheimer’s disease patients.”