Periodic Reporting for period 2 - DELIVER (Release of engineered extracellular vesicles for delivery of biotherapeutics)
Reporting period: 2022-09-01 to 2024-02-29
The development of biological medicines has surged in recent years due to their enormous potential for treating a multitude of different diseases. Such medicines include nucleic acid- and protein-based therapeutics, which can be used to regulate the expression of genes aiming to prevent faulty proteins from being produced, to repair proteins or even to replace them. However, their widespread use is especially hampered by delivery issues. These medicines need to be encapsulated into nanocarriers to ensure their stability and efficient uptake into cells. To that end, many different approaches have been and are being developed, most of which end up in the liver making treatment of other organs a crucial challenge. In my lab we are developing strategies to engineer extracellular vesicles (EVs), tiny membranous vesicles, for their use as a drug delivery tool. Due to their natural origin, EVs are immune privileged and can cross biological barriers, including the blood-brain barrier. The DELIVER project aims to turn the liver into a “biofactory” to produce EVs that are then excreted into the circulation to reach other organs where they can release their therapeutic cargo. Within this project, the initial goals are to find the right instructions to achieve efficient production of EVs in the liver and to deliver these instructions safely and potently. Once this has been achieved, different engineering approaches will be explored with the aim of targeting these EVs to the central nervous system (CNS). Apart from that, to minimize systemic exposure the instructions will be delivered directly into the cerebrospinal fluid (CSF) to enhance local production of EVs in the CNS. The therapeutic potential of this approach will be evaluated in a Parkinson’s disease model. However, this DELIVER platform is intended to serve as a steppingstone for a variety of therapeutic applications involving disease-causing proteins since it is applicable to a wide range of biotherapeutics and thus treatment of various diseases.
Thus far, we have conducted the largest study to date to screen for novel EV-sorting proteins that can be used for efficient production of EVs loaded with a cargo of interest. This study led to the discovery of two novel EV-sorting proteins, which are outcompeting the current state of the art in the field. Their potential for producing EVs in the liver is currently under evaluation showing promising initial results that demonstrate the feasibility of our approach. Additionally, we have identified strategies to improve EV-mediated delivery of cargos such as proteins and nucleic acids. These include components to enhance endosomal escape of EVs and to dissociate the cargo from the EV in the target cell, both of which ensure that the cargo reaches its intended site of action within the cell. EVs produced with these components that were produced conventionally in the lab have been shown to potently deliver gene editing modalities to the CNS in mice. Soon, these findings will be integrated into the instructions to produce EVs with therapeutically relevant cargos in the liver and the CNS.
One major finding so far is the discovery of novel EV-sorting proteins, which provides a new steppingstone for EV-based engineering approaches. Additionally, we developed potent strategies to deliver biological therapeutics such as gene editing modalities and mRNA with EVs. This knowledge can be combined and harnessed to produce EVs loaded with therapeutics in the liver. These EVs can then travel to other organs to release their cargo and induce therapeutic effects. Using this strategy, we are focusing on two different therapeutic approaches. One is based on gene editing modalities, which require only temporary presence of the cargo in the target cell to induce permanent changes in disease-causing genes. The other one is focused on continuous production of EVs to achieve sustained protein replacement in target cells. Since EVs tend to accumulate in the endo-lysosomal pathway in target cells the latter can be used to treat lysosomal storage disorders which are implicated in e.g Parkinson’s disease. However, the goal is to develop a platform that can be used for a variety of therapeutic modalities and dieases. This would open up many possibilites for these types of therapeutics since their delivery especially to other organs than the liver is one if not the biggest hurdle for unlocking their full potential.