Stem cell stories that caught our eye: improving heart care, fixing sickle cell disease, stem cells & sugar

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.

Using “disease in a dish” model to improve heart care
Medications we take to improve our quality of life might actually be putting our lives in danger. For example, some studies have shown that high doses of pain killers like ibuprofen can increase our risk of heart problems or stroke. Now a new study has found a way of using a person’s own cells, to make sure the drugs they are given help, and don’t hinder their recovery.

cardiacdisea

Cardiac muscle cells from boy with inherited heart arrhythmia.
Image: Emory University

Researchers at Emory University in Atlanta took skin cells from a teenage boy with an inherited heart arrhythmia, and turned them into induced pluripotent stem (iPS) cells – a kind of cell that can then be turned into any other cell in the body. They then turned the iPS cells into heart muscle cells and used those cells to test different medications to see which were most effective at treating the arrhythmia, without causing any toxic or dangerous side effects.

The study was published in Disease Models & Mechanisms. In a news release co-author Peter Fischbach, said the work enables them to study the impact on a heart cell, without taking any heart cells from patients:

“We were able to recapitulate in a petri dish what we had seen in the patient. The hope is that in the future, we will be able to do that in reverse order.”

Switching a gene “off” to ease sickle cell disease pain:
Sickle cell disease (SCD) is a nasty, inherited condition that not only leaves people in debilitating pain, but also shortens their lives. Now researchers at Dana-Farber and Boston Children’s Cancer and Blood Disorders Center have found a way that could help ease that pain in some patients.

SCD is caused by a mutation in hemoglobin, which helps carry oxygen around in our blood. The mutation causes normally soft, round blood cells to become stiff and sickle-shaped. These often stick together, blocking blood flow, causing intense pain, organ damage and even strokes.

In this study, published in the Journal of Clinical Investigation, researchers took advantage of the fact that SCD is milder in people whose red blood cells have a fetal form of hemoglobin, something which for most of us tails off after we are born. They found that by “switching off” a gene called BCL11A they could restart that fetal form of hemoglobin.

They did this in mice successfully. Senior author David Williams, in a story picked up by Health Medicine Network, says they now hope to try this in people:

“BCL11A represses fetal hemoglobin, which does not lead to sickling, and also activates beta hemoglobin, which is affected by the sickle-cell mutation. So when you knock BCL11A down, you simultaneously increase fetal hemoglobin and repress sickling hemoglobin, which is why we think this is the best approach to gene therapy in sickle cell disease.”

CIRM already has a similar approach in clinical trials. UCLA’s Don Kohn is using a genetic editing technique to add a novel therapeutic hemoglobin gene that blocks sickling of the red blood cells and hopefully cure the patient altogether. This fun video gives a quick summary of the clinical trial:


How a stem cell’s sugar metabolism controls its transformation potential
While CIRM makes its push to fund 50 more stem cell-based clinical trials by 2020, we also continue to fund research that helps us better understand stem cells. Case in point, this week a UCLA research team funded in part by CIRM reported that an embryonic stem cell’s sugar metabolism changes as its develops and that this difference has big implications on cell fate.

glucose

Glucose

The study, published in Cell Stem Cell, compared so-called “naïve” and “primed” human embryonic stem cells (ESCs). The naïve cells represent a very early stage of embryo development and the primed cells represent a slightly later stage. All cells use the sugar, glucose, to provide energy, though the researchers discovered that the naive stem cells “ate up” glucose four times faster than the primed stem cells (A fascinating side note is they also found the exact opposite behavior in mice: naïve mouse ESCs metabolize glucose slower than primed mouse ESCs. This is a nice example of why it’s important to study human cells to understand human biology). It turns out this difference effects each cells ability to differentiate, or specialize, into a mature cell type. When the researchers added a drug that inhibits glucose metabolism to the naïve cells and stimulated them down a brain cell fate, three times more of the cells specialized into nerve cells.

Their next steps are to understand exactly how the change in glucose metabolism affects differentiation. As Heather Christofk mentioned in a university press release, these findings could ultimately help researchers who are manipulating stem cells to develop cell therapy products:

“Our study proves that if you carefully alter the sugar metabolism of pluripotent stem cells, you can affect their fate. This could be very useful for regenerative medicine.”

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