Ebv/host synthetic lethal screens to identify therapeutic targets for multiple sclerosis
Genome-wide CRISPR/Cas9 screens to discover host gene vulnerabilities in B cells latently infected with Epstein-Barr Virus (EBV), enabling targeted depletion of EBV-infected B cells for multiple sclerosis (MS) treatment. Validated approach using SARS-CoV-2 and EBV latency protein screens, with potential to identify repurposed or novel host-directed antiviral drugs.
Overview
This research program uses genome-wide CRISPR/Cas9 dropout screens to identify human host genes that become essential for survival specifically in B cells latently infected with Epstein-Barr Virus (EBV). The goal is to uncover therapeutic targets that can selectively eliminate EBV-infected B cells, which recent evidence strongly implicates as essential drivers of multiple sclerosis (MS). By exploiting virus/host synthetic lethal interactions, the approach aims to identify both existing drugs that could be repurposed for MS treatment and novel host-directed antiviral agents.
Technical specifications
Core approach:
- Genome-wide CRISPR/Cas9 knockout library (TKOv3) targeting 18,056 human mRNA-encoding genes
- Dropout screens in EBV-positive and EBV-negative B cell lines (AKATA, RAMOS) and other cell lines (AGS gastric carcinoma, HEK293 embryonic kidney)
- Quantitative genetic interactions (qGI) algorithm to identify new vulnerabilities caused by EBV gene expression
- Individual EBV latency protein expression screens to assign hits to specific viral proteins
- Confirmation of top hits with targeted lentiviral CRISPR/Cas9 vectors
- Identification of enriched protein complexes and pathways among confirmed hits
- Evaluation of existing drugs targeting identified hits and assessment of novel drug target potential
Validation precedent:
- SARS-CoV-2 S protein screens identified proteasome subunits as synthetic lethal partners; bortezomib (FDA-approved proteasome inhibitor) inhibited SARS-CoV-2 growth in lung cancer cells and normal human nasal epithelial cells
- EBV EBNA1 expression in AGS cells revealed mitochondrial complex I vulnerabilities; AGS-EBNA1 cells showed increased sensitivity to complex I inhibitors BAY87-2243 and metformin
Technology readiness level
The underlying virus/host synthetic lethal screening methodology has been validated through successful SARS-CoV-2 and EBV EBNA1 proof-of-concept studies, demonstrating that the approach can identify druggable vulnerabilities and confirm them with existing pharmacological agents. The proposed MS-focused work represents an application of this validated platform to identify new therapeutic targets. Current activities involve screening and hit confirmation, with pathway and drug identification as next steps toward potential therapeutic development for MS.
About University of Toronto
The University of Toronto is a comprehensive public research university with three campuses in the Toronto region and a globally scaled research enterprise. Its downtown footprint is embedded within a major academic health network and an adjacent innovation district, enabling co-located labs, clinical trials, and rapid testing with end users. Companies connect through co-op and long-duration internships, sponsored research, and access to shared core facilities and prototyping resources. Research is supported by Canada’s Tri‑Agency (NSERC, CIHR, SSHRC) and the Canada Foundation for Innovation, alongside provincial programs and industry partnerships. A dedicated technology transfer office provides IP management, licensing, and startup support through a coordinated entrepreneurship network.
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