Reprogramming Human Envelope Proteins for Neuronal Genome Editing

About the project

About the Project Targeted delivery remains the principal bottleneck for therapeutic genome editing, particularly in the central nervous system where efficient delivery to defined neuronal populations remains challenging. We hypothesize that endogenous human viral envelope proteins, derived from domesticated human endogenous retroviruses (hERVs), represent an evolutionarily optimized yet largely unexplored source of minimally immunogenic targeting molecules that can be engineered into programmable delivery modules for CRISPR ribonucleoprotein (RNP) therapeutics. Building on our hERV-derived CRISPR RNP delivery platform, we will use comparative genomics, AI-guided structural modelling and functional screening to identify, prioritize and engineer endogenous human envelope proteins for selective targeting of disease-relevant neuronal cell types. Lead envelopes will be engineered to minimize off-target liver tropism and reprogrammed with interchangeable targeting ligands, including single-chain variable fragments (scFvs), nanobodies, and DARPins, to enable programmable cell-type specificity. The most promising variants will be selected in iPSC-derived neuronal models and comparatively evaluated using multiplexed UMI-based screening in human brain slices and in vivo mouse models. Project Objectives Discover endogenous human envelope proteins with receptor-binding properties that enable selective CRISPR RNP delivery to distinct neuronal cell types in the human brain. Engineer lead envelope proteins into programmable targeting modules by optimising fusogenic activity and incorporating interchangeable targeting ligands (e.g. targeting peptides) to enable selective neuronal delivery. Evaluate dual-pseudotyping strategies by combining complementary envelope proteins to enhance neuronal targeting, transduction efficiency, and tissue specificity. Develop a multiplexed in vivo barcoding platform by encoding unique molecular identifiers (UMIs) within the sgRNA scaffold to enable accurate tracking and deconvolution of pooled engineered human envelopes following systemic or local brain administration in mice. Validate lead UMI-tagged engineered human envelopes in the BEXORG human brain model by assessing neuronal targeting, genome-editing efficiency, specificity, and toxicity. Research Methodologies We will identify endogenous human envelope proteins and engineer their targeting properties for selective delivery to neuronal cell populations. Native receptor-binding sites will be mutated to reduce off-target liver tropism before retargeting envelopes with interchangeable ligands (e.g. scFvs and DARPins) directed against cell surface markers specific to the neuronal cell type of interest. Lead envelopes will be selected in iPSC-derived neuronal models and human brain slices. We will establish and validate a multiplexed in vivo barcoding platform in mice for pooled tracking of engineered human envelopes. This platform will enable multiplexed evaluation of engineered human envelopes in scarce translational brain models, including BEXORG human brains, allowing multiple candidates to be assessed within a single specimen. Potential Project Impact This project has the potential to transform genomic medicine by overcoming one of its greatest challenges: the safe and precise delivery of genome-editing therapies. By developing a programmable delivery platform built entirely from human proteins, we aim to enable targeted, minimally immunogenic delivery to the brain and other tissues. Beyond accelerating the development of treatments for neurological and inherited diseases, the platform could be broadly adapted for diverse genome-editing applications. Proposed Project Timelines Year 1: Discover and prioritise endogenous human envelope proteins through computational genome mining, AI-guided structural modelling and functional screening to establish an initial library of candidate neuronal targeting modules. Year 2: Functionally characterise and engineer lead envelopes into programmable targeting modules by optimising fusogenic activity and incorporating interchangeable targeting ligands and optimise neuronal targeting in iPSC-derived neuronal models. Year 3: Develop and validate a multiplexed barcoded in vivo screening platform in mice for pooled comparative evaluation of engineered neuronal delivery systems following systemic and local brain administration. Year 4: Validate lead delivery platforms in the BEXORG ex vivo human brain model, protect key intellectual property, and advance the platform towards preclinical development. Potential Internship/Exceptional Training Opportunities The project provides interdisciplinary training in computational genome mining, protein engineering, genome editing, viral vector development, and translational medicine. The successful candidate will gain hands-on experience in molecular cloning, lentiviral pseudotyping, CRISPR RNP delivery, scalable vector manufacturing, multiplexed in vivo screening, and functional genomics. The student will work within the MRC CoRE, collaborating with national and international partners, with potential opportunities for an internship at BEXORG. The student will receive multidisciplinary supervision, mentor undergraduate and MSc students, present at international conferences, and engage with Oxford's innovation ecosystem. Opportunities for student participation in PPIE The DPhil student will actively participate in public and patient involvement and engagement (PPIE) activities to promote dialogue around genome editing and genetic medicines. These include student-led participation in public engagement events, such as the annual Health Showcase in central Oxford, engaging with patient and public groups through MRC CoRE activities, and contributing to educational outreach through organisations such as the British Society for Gene and Cell Therapy (BSGCT). These experiences will strengthen communication skills, enhance understanding of patient perspectives, and ensure that development of human-derived genome-editing delivery technologies remains aligned with patient needs. MRC CoRE-TG Scholarships Applicants to MRC CoRE-TG projects may be nominated for a CoRE-TG DPhil scholarship, which involves a second interview following the departmental interview. Due to UKRI limits on international student recruitment, only UK home students are eligible for these MRC CoRE-TG DPhil scholarships. For information on home student eligibility, please refer to UKRI training grants: standard terms and conditions of training grant sections TGC 5.2.4 & TGC 5.2.5. The MRC CoRE-TG DPhil scholarship provides funding for: Course fees for the duration of fee liability. A living stipend at the UKRI rate, paid for four years. A £20,000 Research Training Support Grant (RTSG) to support research and training costs. A £1,200 travel allowance to support research-related travel and development opportunities. The stipend rate is reviewed annually by UKRI/MRC. Overseas applicants are still welcome to apply for MRC CoRE-TG projects. They may be considered for other funding opportunities available through the relevant department and may also apply for external scholarship funding independently to support their DPhil. Ready to join us? Applications are competitive and will be assessed according to the admissions requirements of the relevant host department or university. For questions about the MRC CoRE in Therapeutic Genomics programme , please contact mrccoretg@paediatrics.ox.ac.uk Scholarship Code: CoRE-TG 2026-001

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