New gene editing approach for alpha-1 antitrypsin deficiency shows promise

October 20, 2017 by Jim Fessenden, University of Massachusetts Medical School
Credit: CC0 Public Domain

A new study by scientists at UMass Medical School shows that using a technique called "nuclease-free" gene editing to correct cells with the mutation that causes a rare liver disease leads to repopulation of the diseased liver with healthy cells. Alpha-1 antitrypsin deficiency is an inherited disease that causes liver and lung damage; the Mueller lab's approach to the disease, led by postdoc Florie Borel, PhD, and published in the journal Molecular Therapy, combines the use of RNA interference with gene augmentation, using an RNAi-resistant version of the alpha-1 antitrypsin gene. This dual treatment has the potential to prevent both liver and lung damage from forming in very young patients.

"This is a significant win for ," said Christian Mueller, PhD, associate professor of pediatrics and senior author of the study. "If healthy or gene-corrected liver have a selective advantage over cells with the alpha-1 antitrypsin deficiency mutation, then it is possible that by treating only a few cells, those will 'outcompete' the diseased cells. And because liver cells regenerate easily, this can create a big advantage therapeutically."

Alpha-1 antitrypsin deficiency, or "alpha-1," is a single gene disorder. A mutation causes the misfolding of the alpha-1 protein, leading to the loss of its normal biological function. Without the protective activity of this protein, certain enzymes damage the lungs, leading to emphysema and chronic obstructive pulmonary disease, a debilitating and potentially deadly condition that often remains undiagnosed. In about 10 percent of patients, this misfolded protein, which also accumulates in the liver, can cause damage leading to cirrhosis of the liver.

Currently, there is no curative treatment for the disease; many people with the disease manage the symptoms with intravenous infusions of alpha-1 antitrypsin purified from donated human plasma. New clinical approaches using gene therapy and gene editing form the basis of a treatment to remove the source of the toxic protein in the liver, while ramping up production of healthy alpha-1 proteins.

Alpha-1 antitrypsin deficiency affects at least 100,000 people in the United States. An estimated 20 million people carry the gene for the disease and could pass it to their children. That's as many as carry mutations for cystic fibrosis, which is much more widely recognized.

"Gene editing with alpha-1 antitrypsin deficiency alone can do a lot of what CRISPR/Cas9 [currently the most widely-studied gene editing tool] does, just at a lower efficiency," said Mueller. "In cases where there is a competitive advantage, only a low-level of editing is necessary, allowing the corrected cells to expand and, in this case, both prevent liver disease and make therapeutic levels of the normal alpha-1 protein."

The key to the new discovery was inspired by a collaboration with Lenny Schultz, PhD, professor at the Jackson Laboratory, and the labs of Michael Brehm, PhD, associate professor of molecular medicine; Dale Greiner, PhD, the Dr. Eileen L. Berman and Stanley I. Berman Foundation Chair in Biomedical Research and professor of molecular medicine; and Terence R. Flotte, MD, the Celia and Isaac Haidak Professor of Medical Education, executive deputy chancellor, provost and dean of the School of Medicine, at UMMS. They worked to develop a new humanized mouse model with the mutation that causes alpha-1 antitrypsin deficiency. Other mouse models are very fragile, explained Mueller.

Future research will include a formal toxicology study. Currently, there is no large animal model of alpha-1 antitrypsin deficiency that would allow preclinical testing.

"What we have here is a proof of concept that this approach would potentially help patients," said Mueller. "And for very young patients with actively growing livers that could potentially be treated early in life, this could be very meaningful."

Explore further: A finding that could help Alpha-1 sufferers breathe more easily

More information: Florie Borel et al. Survival advantage of both human hepatocyte xenografts and genome edited hepatocytes for treatment of α-1 antitrypsin deficiency, Molecular Therapy (2017). DOI: 10.1016/j.ymthe.2017.09.020

Related Stories

A finding that could help Alpha-1 sufferers breathe more easily

December 13, 2012
Scientists have identified a new mutation in the gene that causes the inherited disease known as Alpha-1 Antitrypsin Deficiency (Alpha-1), which affects roughly one in 2,500 people of European descent.

New targeted gene therapy could lead to improved treatment for emphysema

July 5, 2016
Researchers have developed a new strategy using lung-targeted gene therapy that may lead to improved treatments for inherited diseases including emphysema.

Oxidative stress and altered gene expression occurs in a metabolic liver disease model

October 30, 2012
A team of researchers under the direction of Dr. Jeffrey Teckman in the Department of Pediatrics at St. Louis University, have demonstrated that oxidative stress occurs in a genetic model of alpha-1-antitrypsin deficiency. ...

RCSI research breakthrough in understanding hereditary emphysema

January 13, 2014
Researchers from the Royal College of Surgeons in Ireland (RCSI) and Beaumont Hospital have made an important breakthrough in the understanding and treatment of hereditary emphysema.  Their research findings were published ...

Study shows treatment for genetically caused emphysema is effective

May 28, 2015
A landmark clinical study in the Lancet provides convincing evidence that a frequently overlooked therapy for genetically-caused emphysema is effective and slows the progression of lung disease.

Recommended for you

Discovery of the 'pioneer' that opens the genome

January 23, 2018
Our genome contains all the information necessary to form a complete human being. This information, encoded in the genome's DNA, stretches over one to two metres long but still manages to squeeze into a cell about 100 times ...

Researchers identify gene responsible for mesenchymal stem cells' stem-ness'

January 22, 2018
Many doctors, researchers and patients are eager to take advantage of the promise of stem cell therapies to heal damaged tissues and replace dysfunctional cells. Hundreds of ongoing clinical trials are currently delivering ...

Genes contribute to biological motion perception and its covariation with autistic traits

January 22, 2018
Humans can readily perceive and recognize the movements of a living creature, based solely on a few point-lights tracking the motion of the major joints. Such exquisite sensitivity to biological motion (BM) signals is essential ...

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

Two new breast cancer genes emerge from Lynch syndrome gene study

January 18, 2018
Researchers at Columbia University Irving Medical Center and NewYork-Presbyterian have identified two new breast cancer genes. Having one of the genes—MSH6 and PMS2—approximately doubles a woman's risk of developing breast ...

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.