Rapid Surface Display of mRNA Antigens by Bacteria‐Derived Outer Membrane Vesicles for a Personalized Tumor Vaccine

Abstract

mRNA vaccines can encode one or more tumor specific antigens, derived from genetic mutations, and undergo intracellular protein translation and antigen processing to form complexes with the major histocompatibility complex I (MHCI) in antigen presenting cells (APCs), mainly DC cells (DCs), ultimately presenting the antigens to T cells to induce a robust tumor-specific T cell response. [3,4] This intracellular antigen production and processing approach employed by mRNA vaccines is particularly suitable for a tumor vaccine because the pathway mimics the natural generation of tumor antigens within cancer cells. [5] The ability to enter APCs has been considered an essential prerequisite for effective immune activation by an mRNAbased tumor vaccine. [6] However, due to its poor stability, large molecular weight and highly negative charge, an mRNA vaccine must rely on potent delivery carriers to enter cells. [7,8] Until now, the major mRNA carriers for in vivo delivery in the clinic are lipid nanoparticles (LNPs), which encapsulate mRNA within nanocarriers through a microfluidic-based synthesis process. [9][10][11] Because of the heterogeneity and complexity of Therapeutic mRNA vaccination is an attractive approach to trigger antitumor immunity. However, the mRNA delivery technology for customized tumor vaccine is still limited. In this work, bacteria-derived outer membrane vesicles (OMVs) are employed as an mRNA delivery platform by genetically engineering with surface decoration of RNA binding protein, L7Ae, and lysosomal escape protein, listeriolysin O (OMV-LL). OMV-LL can rapidly adsorb box C/D sequence-labelled mRNA antigens through L7Ae binding (OMV-LL-mRNA) and deliver them into dendritic cells (DCs), following by the crosspresentation via listeriolysin O-mediated endosomal escape. OMV-LL-mRNA significantly inhibits melanoma progression and elicits 37.5% complete regression in a colon cancer model. OMV-LL-mRNA induces a long-term immune memory and protects the mice from tumor challenge after 60 days. In summary, this platform provides a delivery technology distinct from lipid nanoparticles (LNPs) for personalized mRNA tumor vaccination, and with a "Plug-and-Display" strategy that enables its versatile application in mRNA vaccines.

The landscape of mRNA nanomedicine

“…Biological membrane-based vehicles represent another novel biocompatible platform for mRNA delivery. Distinct types of biological membrane-based systems, including cell membrane vesicles 135 , bacteria-derived outer-membrane vesicles 136 and extracellular vesicles 137 (for example, exosomes 138 ), have been employed for in vitro and in vivo delivery of therapeutic mRNAs. As a type of nanoscale extracellular vesicle, exosomes have been widely investigated as carriers for drug delivery 139,140 .…”

Bacterial outer membrane vesicle-based cancer nanovaccines

“…Oral arabinose induces the bacterial robot to produce OMVs carrying tumor antigens in situ in the intestines, thereby activating strong anti-tumor immune responses and immune memory effects (Figure 3D). To expand the application of tumor vaccine types, Li et al 67 have modified RNA binding protein on the surfaces of OMVs through fusion protein expression, and used box C/D sequence-labeled mRNA antigens to adsorb antigens on the surfaces of OMVs. This is the first time that OMVs were successfully been used as an mRNA delivery platform.…”

Extracellular Vesicles as Delivery Vehicles for Therapeutic Nucleic Acids in Cancer Gene Therapy: Progress and Challenges

“…Recently, it has been reported that the use of Gram-negative bacteria-derived outer-membrane vesicles (OMVs) as an mRNA delivery platform strongly stimulates the innate immune system, promoting antigen presentation and T cell activation. Moreover, OMVs generated after surface modification of the RNA-binding protein L7Ae and the lysosomal escape protein Listerinolysin O (OMV-LL-mRNA) can significantly inhibit tumor progression, induce long-term immune memory, and protect mice from tumor challenges after 60 days [ 135 ].…”