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Genome-wide RNAi Screening to Identify Host Factors That Modulate Oncolytic Virus Therapy
Published on: April 3, 2018
Survival-based CRISPR genetic screens across a panel of permissive cell lines identify common and cell-specific
Katherine Chan1, Adrian Granda Farias1,2, Hunsang Lee1
1Donnelly Center, 160 College Street, University of Toronto, Toronto, Ontario, Canada, M5S3E1.
Abstract:
SARS-CoV-2 depends on host cell components for infection and replication. Identification of virus-host dependencies offers an effective way to elucidate mechanisms involved in viral infection and replication. If druggable, host factor dependencies may present an attractive strategy for anti-viral therapy. In this study, we performed genome wide CRISPR knockout screens in Vero E6 cells and four human cell lines including Calu-3, UM-UC-4, HEK-293 and HuH-7 to identify genetic regulators of SARS-CoV-2 infection. Our findings identified only ACE2, the cognate SARS-CoV-2 entry receptor, as a common host dependency factor across all cell lines, while other host genes identified were largely cell line specific, including known factors TMPRSS2 and CTSL. Several of the discovered host-dependency factors converged on pathways involved in cell signalling, immune-related pathways, and chromatin modification. Notably, the chromatin modifier gene KMT2C in Calu-3 cells had the strongest impact in preventing SARS-CoV-2 infection when perturbed.
Insights
Researchers identified host cell factors crucial for SARS-CoV-2 infection using CRISPR screens. Only ACE2 was a common factor across all cell types, highlighting cell-specific dependencies for potential antiviral therapies.
Area of Science:
- Virology
- Genetics
- Cell Biology
Background:
- Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) relies on host cell machinery for its life cycle.
- Understanding virus-host interactions is key to developing antiviral strategies.
- Host dependency factors, if targetable, offer potential therapeutic avenues.
Purpose of the Study:
- To identify host genetic factors regulating SARS-CoV-2 infection across various cell types.
- To explore potential antiviral targets by pinpointing essential host dependencies.
Main Methods:
- Genome-wide CRISPR knockout screens were conducted in multiple cell lines (Vero E6, Calu-3, UM-UC-4, HEK-293, HuH-7).
- Analysis focused on identifying genes essential for SARS-CoV-2 replication and infection.
Main Results:
- Angiotensin-converting enzyme 2 (ACE2) was the sole common host dependency factor identified across all tested cell lines.
- Other identified host factors, including TMPRSS2 and CTSL, were largely cell line-specific.
- Convergent pathways implicated included cell signaling, immune responses, and chromatin modification.
- Perturbation of the chromatin modifier KMT2C in Calu-3 cells showed the most significant impact on inhibiting SARS-CoV-2 infection.
Conclusions:
- Host dependency for SARS-CoV-2 infection is predominantly cell-type specific, with ACE2 being a universal factor.
- The study reveals novel host factors and pathways involved in viral infection, offering potential targets for antiviral drug development.
- Targeting specific host factors like KMT2C could represent a promising strategy for therapeutic intervention against SARS-CoV-2.
