Engineered red blood cell vesicles advance gene therapy and tumor-targeting delivery
核心洞察
Scientists at The Ohio State University engineered extracellular vesicles from red blood cell lipids using microfluidics, creating nanocarriers that evade immune cells and target cancer cells.
The platform packages cargo ranging from genetic material and proteins to whole adeno-associated viruses, with a CD47 (搜索) peptide protecting carriers from macrophage clearance.
Anti-PD-L1 (搜索)-tagged vesicles showed preferential uptake in PD-L1-positive breast cancer (搜索) tumors, and encapsulated AAVs were shielded from neutralizing antibodies.
Scientists at The Ohio State University have developed engineered extracellular vesicles (EVs) built from red blood cell lipids that show promise as effective and efficient vehicles for gene therapy, tumor targeting, and other medical treatments. The platform, described in a study published in the journal Advanced Healthcare Materials, demonstrated two capabilities that could improve the delivery of future therapies: the ability to evade immune cells and the ability to target cancer cells.
The technology offers exceptional flexibility. By assembling the vesicles from red blood cell lipids using microfluidics, researchers were able to package cargo ranging from genetic material and proteins to whole viruses used in gene therapy. In mice, the engineered vesicles remained in circulation and were distributed to multiple organs in patterns similar to those of naturally occurring extracellular vesicles, with notable accumulation in the lungs.
Engineering for biocompatibility and controllability
The researchers initially set out to make delivery devices from natural extracellular vesicles generated by red blood cells, but encountered limitations in scaling up production and cargo-loading flexibility. They turned to engineering techniques to improve upon what nature had to offer.
"In terms of lipid composition, they basically match very closely with what the natural extracellular vesicles from red blood cells would have," said senior author Eduardo Reátegui, professor of chemical and biomolecular engineering at Ohio State. "We are keeping some of the great biological advantages that these particles have by themselves because they are very biocompatible."
The source cells for the lipids are expired red blood cells (RBCs) obtained from the lab of co-author Andre Palmer, professor of chemical and biomolecular engineering and an Ohio Eminent Scholar at Ohio State. "We're always purifying hemoglobin from expired red blood cells," said Palmer, whose lab uses the hemoglobin as a building block for making red blood cell substitutes. "The approach here is very sustainable because these expired red blood cells otherwise would be thrown out since they cannot be transfused into patients."
Beyond the biocompatibility provided by red blood cell lipids, microfluidics enables therapeutic cargo to be incorporated as the vesicles form, eliminating the need for separate cargo-loading steps afterward. "We're not saying our process is better. We're claiming that we have a lot more controllability in terms of what we want the composition of this engineered vesicle to look like," said Reátegui, also a member of the Cancer Biology Program in The Ohio State University Comprehensive Cancer Center.
Immune evasion and tumor targeting
Experiments showed that attaching a CD47 (搜索) peptide to the carriers' outer surface protected them from being mistaken for pathogens and eaten by macrophages. The team also demonstrated that the vesicles could be engineered for tumor targeting by adding PD-L1 (搜索)-recognition molecules, including anti-PD-L1 nanobodies developed in the lab of co-author Blaise Kimmel, and by showing preferential uptake of anti-PD-L1-tagged vesicles in PD-L1-positive breast cancer (搜索) tumors that are often targeted by immunotherapy.
The researchers noted that these engineered EVs could function similarly to cancer CAR T-cell therapies that are made from a patient's own immune system T cells. "It could be a unique way of using a person's own red blood cell lipids to then encapsulate therapeutic materials that could be delivered back to that patient to potentially cure a disease," Palmer said.
Protecting gene therapy cargo
The microfluidics method also enables inclusion of comparatively large molecules, such as whole proteins or even an adeno-associated virus (搜索) (AAV), the established delivery system for many gene therapies. Encasing a therapeutic AAV inside an engineered red blood cell extracellular vesicle tagged with the CD47 (搜索) peptide could reduce the chances of triggering an immune response, Reátegui said.
"Our thought was to take these AAV particles and encapsulate them inside engineered RBC extracellular vesicles. We tested if the gene therapy would still work and be delivered into cells, and we show that it would. And we also demonstrated that the AAVs would be protected from neutralizing antibodies," he said.
With the platform in place, the researchers aim to narrow their focus to gene therapy and delivery of select therapeutics, particularly those that capitalize on the EVs' affinity for the lungs.
This research was supported by the National Center for Advancing Translational Sciences, and Ohio State's William G. Lowrie Department of Chemical and Biomolecular Engineering and Comprehensive Cancer Center. Co-authors include Chiranth Nagaraj, Xilal Rima, Kim Nguyen, Courtney Culkins, Nana Boateng, Jacob Doon-Ralls, Alejandro Bresolin, Xin Huang, Vahedi Amid, Ajeet Pal Singh, Dharti Shantaram, Anastasiia Amari, Nicholas Merriam, Zachary Schultz, Willa Hsueh, and Rachel Kopec of Ohio State; and Hong Li, Scott Harper, Nizar Saad, and Setty Magaña of Nationwide Children's Hospital.