Asymmetric vesicles for nucleic acid therapies
Nucleic acid therapies are a rapidly expanding field with transformative potential for medicine. While sequences can be designed for any nucleic acid, the pharmacokinetic properties are determined independently by the delivery vector. The diversity of nucleic acid therapies means that a “one size fits all” approach to delivery is not sufficient. Nature uses vesicles for cell-to-cell nucleic acid transfer in the form of extracellular vesicles (EVs), which are innately biocompatible. However, a crucial bottleneck to their translation to the clinic and large scale production is that they must be isolated from cell media. Additionally, while the role of their surface has been well studied, less is known about their asymmetric lipid membrane roles and composition. Here we will characterise lipid composition of EVs from a range of sources and decouple the lipid content of the inner and outer membranes (WP1). We will optimise methods to formulate a library of asymmetric vesicles loaded with nucleic acids using these EV-mimicking outer and inner leaflet lipid compositions, and study effect of inner-leaflet cationic lipids (WP2). We shall develop state-of-the-art SANS tools to study these systems (WP3) which along with in vitro studies will uncover differences/similarities in intracellular fate of asymmetric vesicles and EVs with highly similar lipid compositions, and identify optimised formulations tailored to of a range of nucleic acid cargoes (WP4).
Popular science description
The Pfizer-BioNTech and Moderna vaccines which have formed a cornerstone of the covid-19 vaccination programme have brought RNA therapies to the world stage. The development and approval of these therapies for use in the clinic was achieved in record time, so it is easy to forget that the lipid nanoparticle carriers they make use of are actually the culmination of over two decades of research. There is nowadays increasing interest in nucleic acid therapies other than mRNA vaccines. Nucleic acids such as RNA and DNA can be designed to target any gene in the body and come in a huge number of shapes and sizes, and require a nanocarrier for their delivery to protect them until they arrive at their target cells. With such a range of nucleic acids comes the need for equally diverse nanocarriers. The lipid nanoparticles used in the covid-19 vaccine have shown to be highly effective for this application, however they do have some drawbacks such as not being able to target specific sites in the body, and many particles not having any cargo inside. The body has devised its own mechanisms for moving nucleic acids such as RNA from one cell to another in the form of extracellular vesicles. These nanocarriers are excreted from almost all cells and are a similar size to lipid nanoparticles. Their outside membrane is made from lipids and proteins, similar to a cell wall, with different lipids and proteins on the outer and inner face. They are inherently biocompatible and have attracted lots of interest as alternative nanocarriers to treat diseases, however they are notoriously difficult to collect from cells and isolate in large enough volumes to be applicable in the clinic. In my lab we will work on building RNA and DNA-containing nanocarriers which mimic the asymmetric lipid composition of extracellular vesicles in the lab, and use them to develop new nucleic acid therapies. We will characterise them using state-of-the-art neutron scattering techniques such as those available at the European Spallation Source which is opening in Lund in 2023.
Margaret Holme (contact)
Chalmers, Life Sciences, Chemical Biology
Swedish Foundation for Strategic Research (SSF)
Project ID: SFF
Funding Chalmers participation during 2023–2027