The Liu Ruqian team at the Broad Institute published a research paper titled "Directed evolution of engineered virus-like particles with improved production and transduction efficiencies" in the journal Nature Biotechnology. The study used directed evolution to develop the fifth generation of engineered virus-like particles (v5 eVLP), which has higher production efficiency and delivery efficiency.
In recent years, researchers have explored the use of virus-like particles (VLPs) as carriers for delivering gene editing tools into cells in vivo or in vitro. VLPs consist of a viral scaffold for packaging and delivering carrier proteins, ribonucleoproteins (RNPs) or mRNA. Therefore, VLP delivery vectors take into account both the efficient transduction and tissue tropism of viral delivery methods, as well as the transient expression and reduced off-target editing of non-viral delivery methods, which is an ideal combination for gene editing applications.
| Cat.No. | Product Name | Price |
|---|---|---|
| VLP-0001 | Chikungunya Virus-Like Particle | Inquiry |
| VLP-0002 | Dengue Virus-Like Particle (Serotype 1) | Inquiry |
| VLP-0007 | Ebola Virus-Like Particle | Inquiry |
| VLP-0008 | Japanese Encephalitis Virus-Like Particle | Inquiry |
| VLP-0009 | Mayaro Virus-Like Particle | Inquiry |
| VLP-AAV001 | AAV1 Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-AAV002 | AAV2 Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-AAV003 | AAV5 Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-AAV004 | AAV6 Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-AAV008 | AAV-Retro Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-AAV009 | AAV-DJ Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-AAV010 | AAV-DJ/8 Virus-Like Particles (Empty Capsids) | Inquiry |
| VLP-N-00001 | Human CCR1 Virus-Like Particles | Inquiry |
| VLP-N-00002 | Human CCR2 Virus-Like Particles | Inquiry |
| VLP-N-00003 | Human CCR5 Virus-Like Particles | Inquiry |
In January 2024, Liu Ruqian's team developed an engineered virus-like particle system for delivering prime editors (PE) - PE-eVLP, which can deliver a complete prime editing system in the form of ribonucleoproteins (RNPs) in vivo for transient prime editing. They performed efficient prime editing in human cells and achieved in vivo base editing and restored partial visual function in two genetic blind mouse models. The PE-eVLP system not only supports transient prime editing in vivo, but also reduces off-target editing, avoids potential carcinogenicity caused by gene integration, and enhances the safety of prime editing.
These favorable properties of eVLP suggest that eVLP is promising as a novel delivery vector for effective in vitro and in vivo delivery of gene-editing RNPs or other therapeutic proteins. However, further improvements in the properties of eVLP are needed to maximize its potential for research and therapeutic applications. In particular, the eVLP packaging efficiency or transduction efficiency should be improved, so that we can achieve more efficient gene editing at a lower eVLP dose.
Laboratory directed evolution is a promising method for improving delivery vectors and has been widely used to develop viral delivery vectors. Existing directed evolution protocols require that each viral variant packages a viral genome that encodes the properties of a specific variant, which allows the selected viral genome to be sequenced to identify variants with desired properties. However, since eVLP does not package any viral genetic material, the application of directed evolution to improve eVLP requires the development of another strategy to encode the identity of the eVLP variant.
To achieve the above goals, the research team developed a directed evolution system in which the guide RNA carried by the RNP packaged by each eVLP variant has a barcode sequence that uniquely identifies the specific eVLP variant. After selection for specific properties, the desired eVLP variants can be identified by sequencing the surviving barcoded guide RNAs.
Figure 1. Validation of the barcoded eVLP evolution system. (Raguram A, et al., 2024)
Using this directed evolution system, the research team constructed a library of eVLP capsid variants and screened them to identify capsid variants that could increase eVLP production in producer cells or enhance eVLP transduction in target cells.
By combining beneficial capsid mutations, the research team developed the fifth-generation (v5) eVLP, which has higher RNP packaging capacity, better post-delivery release, unique capsid structural composition, and 2-4 times higher delivery efficiency to cultured mammalian cells than the previous best fourth-generation (v4) eVLP. Analysis of v5 eVLP showed that these capsid mutations optimized the packaging and delivery of ribonucleoprotein (RNP) cargo and significantly changed the eVLP capsid structure.
Reference
Raguram A, et al. Directed evolution of engineered virus-like particles with improved production and transduction efficiencies. Nature Biotechnology, 2024: 1-13.