April Pyle

Promising results from CIRM-funded projects

/ Kevin McCormack / 1 Comment

Severe Leukocyte Adhesion Deficiency-1 (LAD-1) is a rare condition that causes the immune system to malfunction and reduces its ability to fight off viruses and bacteria. Over time the repeated infections can take a heavy toll on the body and dramatically shorten a person’s life. But now a therapy, developed by Rocket Pharmaceuticals, is showing promise in helping people with this disorder.

The therapy, called RP-L201, targets white blood cells called neutrophils which ordinarily attack and destroy invading particles. In people with LAD-1 their neutrophils are dangerously low. That’s why the new data about this treatment is so encouraging.

In a news release, Jonathan Schwartz, M.D., Chief Medical Officer of Rocket, says early results in the CIRM-funded clinical trial, show great promise:

“Patients with severe LAD-I have neutrophil CD18 expression of less than 2% of normal, with extremely high mortality in early childhood. In this first patient, an increase to 47% CD18 expression sustained over six months demonstrates that RP-L201 has the potential to correct the neutrophil deficiency that is the hallmark of LAD-I. We are also pleased with the continued visible improvement of multiple disease-related skin lesions. The second patient has recently been treated, and we look forward to completing the Phase 1 portion of the registrational trial for this program.”

The results were released at the 23rd Annual Meeting of the American Society of Gene and Cell Therapy.

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These microscopic images show gene expression in muscle stem and progenitor cells as they mature from early development to adulthood (left to right). As part of this process, the cells switch from actively expressing one key gene (green) to another (violet); this is accompanied by the growth of muscle fibers (red).
Photo courtesy: Cell Stem Cell/UCLA Broad Stem Cell Research Center

When you are going on a road-trip you need a map to help you find your way. It’s the same with stem cell research. If you are going to develop a new way to treat devastating muscle diseases, you need to have a map to show you how to build new muscle stem cells. And that’s what researchers at the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at UCLA – with help from CIRM funding – have done.

The team took muscle progenitor cells – which show what’s happening in development before a baby is born – and compared them to muscle stem cells – which control muscle development after a baby is born. That enabled them to identify which genes are active at what stage of development.

In a news release, April Pyle, senior author of the paper, says this could open the door to new therapies for a variety of conditions:

“Muscle loss due to aging or disease is often the result of dysfunctional muscle stem cells. This map identifies the precise gene networks present in muscle progenitor and stem cells across development, which is essential to developing methods to generate these cells in a dish to treat muscle disorders.”

The study is published in the journal Cell Stem Cell.

Family ties help drive UCLA’s search for a stem cell treatment for Duchenne muscular dystrophy

/ Kevin McCormack / Leave a comment

Duchenne

April Pyle, Courtney Young and Melissa Spencer: Photo courtesy UCLA Broad Stem Cell Research Center

People get into science for all sorts of different reasons. For Courtney Young the reason was easy; she has a cousin with Duchenne muscular dystrophy.

Now her work as part of a team at UCLA has led to a new approach that could eventually help many of those suffering from Duchenne, the most common fatal childhood genetic disease.

The disease, which usually affects boys, leads to progressive muscle weakness, which means children may lose their ability to walk by age 12 and eventually results in breathing difficulties and heart disease.

Duchenne is caused by a defective gene, which leads to very low levels of a protein called dystrophin – an important element in building strong, healthy muscles. There are many sections of the gene where this defect or mutation can be found, but in 60 percent of cases it occurs within one particular hot spot of DNA. That’s the area that the UCLA team focused on, helped in part by a grant from CIRM.

Skin in the game

First they obtained skin cells from people with Duchenne muscular dystrophy and turned those into iPS cells. Those cells have the ability to become any other cell in the body and, just as importantly for this research, still retain the genetic code from the person they came from. In this case it meant they still had the genetic defect that led to Duchenne muscular dystrophy.

Then the researchers used a gene editing tool called CRISPR (we’ve written about this a lot in the past, you can a couple of those articles  here and here  and here)  to remove the genetic mutations that cause Duchenne. They then turned those iPS cells into skeletal muscle cells and transplanted them into mice that had the genetic mutation that meant they couldn’t produce dystrophin.

To their delight they found that the transplanted cells produced dystrophin in the mice.

Breaking new ground

April Pyle, a co-senior author of the study, which appears in the journal Cell Stem Cell,  said, in a news release, this was the first study to use human iPS cells to correct the problem in muscle tissue caused by Duchenne:

“This work demonstrates the feasibility of using a single gene editing platform, plus the regenerative power of stem cells to correct genetic mutations and restore dystrophin production for 60 percent of Duchenne patients.”

The researchers say this is an important step towards developing a new treatment for Duchenne muscular dystrophy, but caution there are still many years of work before this approach will be ready to test in people.

For Courtney Young advancing the science is not just professionally gratifying, it’s also personally satisfying:

“I already knew I was interested in science, so after my cousin’s diagnosis, I decided to dedicate my career to finding a cure for Duchenne. It makes everything a lot more meaningful, knowing that I’m doing something to help all the boys who will come after my cousin. I feel like I’m contributing and I’m excited because the field of Duchenne research is advancing in a really positive direction.”