MIT gene-edits mRNA nanoparticles for the first time to fight lung disease
Using these RNA delivery particles, researchers hope to develop new treatments for cystic fibrosis and other lung diseases.
Engineers at the Massachusetts Institute of Technology and the University of Massachusetts School of Medicine have developed nanoparticles that deliver messenger RNA encoding beneficial proteins to the lungs, with potential applications in the treatment of cystic fibrosis and other lung diseases. In a mouse study, the particles facilitated efficient delivery of mRNA encoding CRISPR/Cas9 gene editing components, paving the way for therapeutic nanoparticles that can replace disease-causing genes. The researchers are working on spraying the nanoparticles for inhalation and plan to test the particles in a mouse model of cystic fibrosis and other lung diseases.
Engineers at the Massachusetts Institute of Technology and the University of Massachusetts School of Medicine have developed a new type of nanoparticle that can be injected into the lungs, where they can deliver messenger RNA encoding useful proteins.
The researchers say that if further developed, these particles could offer an inhaled treatment for cystic fibrosis and other lung diseases.
“This is the first demonstration of highly efficient RNA delivery to the lungs in mice. We hope it can be used to treat or repair a number of genetic diseases, including cystic fibrosis,” says Daniel Anderson, professor in the Department of Chemical Engineering at the Massachusetts Institute of Technology and a member of the Institute for Integrative Cancer Research. Koch and the MIT Institute of Medicine. Engineering and Science (IMES).
In a study in mice, Anderson and colleagues used particles to deliver mRNA encoding the machinery needed to edit the CRISPR/Cas9 genes. This could open the door to the development of therapeutic nanoparticles that can cut out and replace disease-causing genes.
The senior authors of the study, published March 30, 2023 in the journal Nature Biotechnology, are Anderson; Robert Langer, professor at the David H. Koch Institute at the Massachusetts Institute of Technology; and Wen Xue, associate professor at the RNA Therapy Institute at the University of Massachusetts School of Medicine. Bowen Lee, former postdoctoral fellow at the Massachusetts Institute of Technology, now an assistant professor at the University of Toronto; Rajit Singh Manan, postdoctoral fellow at the Massachusetts Institute of Technology; and Shun-Qing Liang, postdoctoral fellow at the University of Massachusetts School of Medicine, are the lead authors of the paper.
Orientation to the lungs
Messenger RNA has great potential as a therapeutic agent for the treatment of various diseases caused by defective genes. So far, one obstacle to its deployment has been the difficulty of getting it to the right part of the body without side effects. Injected nanoparticles often accumulate in the liver, so several clinical trials are currently underway evaluating potential mRNA treatments for liver disease. RNA-based Covid-19 vaccines, which are injected directly into muscle tissue, have also proven effective. In many of these cases, the mRNA is encapsulated in a lipid nanoparticle, a fatty sphere that protects the mRNA from premature degradation and helps it enter target cells.
A few years ago, Anderson’s lab began developing particles that could better transfect the epithelial cells that make up the majority of the lung mucosa. In 2019, his lab created nanoparticles that can deliver mRNA encoding a bioluminescent protein to lung cells. These particles were made from polymers rather than lipids, making them easier to disperse for inhalation into the lungs. However, more work is needed on these particles to increase their efficiency and maximize their usefulness.
In their new study, the researchers set out to develop lipid nanoparticles that could act on the lungs. The particles are made up of molecules that have two parts: a positively charged head group and a long lipid tail. The positive charge of the head group helps the particles interact with the negatively charged mRNA and also helps the mRNA escape from the cellular structures that trap the particles when they enter the cells.
Meanwhile, the structure of the lipid tail helps the particles pass through the cell membrane. The researchers came up with 10 different chemical structures for the lipid tails, as well as 72 different headgroups. By testing various combinations of these structures in mice, the researchers were able to identify those most likely to reach the lungs.
In further tests in mice, the researchers showed that they could use the particles to deliver mRNA encoding components of CRISPR/Cas9 designed to excise a stop signal that was genetically coded in the animal’s lung cells. When this stop signal is removed, the fluorescent protein gene is turned on. Measuring this fluorescent signal allows researchers to determine what percentage of cells successfully expressed the mRNA.
The researchers found that after a single dose of mRNA, about 40 percent of lung epithelial cells were transfected. Two doses brought the level to more than 50 percent, and three doses to 60 percent. The most important targets for the treatment of lung diseases are two types of epithelial cells called tuber cells and ciliated cells, and each of them was transfected by about 15 percent.
“This means that the cells that we have been able to edit are really of interest for the treatment of lung diseases,” Li says. “This lipid could allow us to deliver mRNA to the lungs much more efficiently than any other delivery system reported so far.”
The new particles are also rapidly broken down, allowing them to be cleared from the lungs within days and reducing the risk of inflammation. The particles can also be delivered to the same patient multiple times if repeated doses are needed. This gives them an advantage over other mRNA delivery approaches that use a modified version of harmless adenoviruses. These viruses are very efficient in delivering RNA, but they cannot be re-introduced because they elicit an immune response in the host.
“This advance paves the way for promising therapeutic applications of gene delivery to the lungs in a variety of lung diseases,” says Dan Pier, director of the Precision Nanomedicine Laboratory at Tel Aviv University, who was not involved in the study. “This platform offers several advantages over conventional vaccines and treatments, including being cell-free, allowing rapid production, high versatility, and a favorable safety profile.”
To deliver the particles in this study, the researchers used a technique called intratracheal instillation, which is often used as a way to simulate drug delivery to the lungs. Now they are working on making their nanoparticles more stable so they can be sprayed and inhaled with a nebulizer.
The researchers also plan to test the mRNA delivery particles, which could correct a genetic mutation found in a gene that causes cystic fibrosis, in a mouse model of the disease. They also hope to develop treatments for other lung diseases, such as idiopathic pulmonary fibrosis, as well as mRNA vaccines that can be delivered directly to the lungs.
Reference: “Combinatorial design of nanoparticles for lung mRNA delivery and genome editing”, Bowen Li, Rajit Singh Manan, Shun-Qing Liang, Akiva Gordon, Allen Jiang, Andrew Varley, Guangping Gao, Robert Langer, Wen Xue, and Daniel Anderson, 30 years. March 2023, Nature Biotechnology.
The study was funded by Translate Bio, the National Institutes of Health, the Leslie Dan Faculty of Pharmacy Startup Fund, the University of Toronto PRiME Postdoctoral Fellowship, the American Cancer Society, and the Cystic Fibrosis Foundation.