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Genomewide CRISPR knockout screen identified PLAC8 as an essential factor for SADS-CoVs infection.
Longping V Tse1, Rita M Meganck1, Kenza C Araba2
1Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514.
Summary
Swine acute diarrhea syndrome coronavirus (SADS-CoV) requires placenta-associated 8 protein (PLAC8) for infection. Targeting PLAC8 could prevent SADS-CoV outbreaks and protect human populations.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- Zoonotic coronaviruses, including swine acute diarrhea syndrome coronavirus (SADS-CoV), pose significant threats to public health and the economy.
- The lack of vaccines and antivirals against SADS-CoV, coupled with limited knowledge of its host factors, impedes effective response strategies.
- Understanding SADS-CoV host entry mechanisms is crucial for mitigating potential human outbreaks.
Purpose of the Study:
- To identify essential host factors for SADS-CoV infection using a genomewide screening approach.
- To elucidate the mechanism by which identified host factors facilitate SADS-CoV replication.
- To evaluate the potential of identified host factors as targets for antiviral development.
Main Methods:
- Conducted a genomewide CRISPR knockout screen to identify host factors essential for SADS-CoV infection.
- Utilized cell culture models and complemented PLAC8 from various species to confirm its role.
- Employed swine primary intestinal epithelial cell (IEC) culture and immunohistochemistry to study PLAC8 expression in vivo.
Main Results:
- Identified placenta-associated 8 protein (PLAC8) as a critical host factor for SADS-CoV infection.
- Knockout of PLAC8 abolished SADS-CoV infection, which could be restored by PLAC8 from multiple mammalian species, indicating conserved susceptibility.
- PLAC8 knockout delayed and reduced viral subgenomic RNA expression, without affecting viral entry.
- High PLAC8 expression in differentiated IECs and neonatal swine ileal tissue correlated with SADS-CoV susceptibility, unlike in expanding IECs or adult tissue.
Conclusions:
- Placenta-associated 8 protein (PLAC8) is an essential host factor for SADS-CoV infection, playing a conserved role across mammals.
- PLAC8 facilitates SADS-CoV replication by influencing viral RNA expression, not initial entry.
- The expression pattern of PLAC8 in swine intestinal cells and tissues explains the age-dependent susceptibility to SADS-CoV.
- PLAC8 represents a promising therapeutic target for developing antivirals against SADS-CoV to prevent future pandemics.
