SARS-CoV-2 exposed : cell cycle disruption and CRISPR-Cas knockdown

Coronaviruses showed their capacity to spread to pandemic levels during the COVID-19 pandemic. Their ability to rapidly spread and to cause severe disease has made them a significant threat to global public health. Novel antiviral treatments with broad-spectrum activity and a persistent effect is of great need, both for reemerging outbreaks of SARS-CoV-2 and for preparedness of new, emerging viruses.

In Paper I, we explore an RNA-targeting CRISPR-Cas13b system that targets viral genomic material, in this case SARS-CoV-2 RNA. Antiviral programmed CRISPR- Cas systems have previously shown to be effective against several viruses, while also exhibiting a robustness to viral mutations. In this paper we show that CRISPR- Cas13b can target and degrade SARS-CoV-2 and that targeting the non-structural protein NSP12 leads to the largest decrease in viral RNA. We also show that CRISPR-Cas13b designed to target SARS-CoV-2 have an effect against SARS-CoV, pointing at a broad-spectrum effect.

In Paper II, we explore how SARS-CoV-2 infection benefits from a host cell cycle arrest. It has previously been shown that SARS-CoV-2 infection drives a host cell cycle arrest, and we could confirm that by inducing a cell cycle arrest independent of p53, but dependent on the CDC25A/CDK2/cyclin E pathway SARS-CoV-2 infection is increased. This work provides important insights into SARS-CoV-2 pathogenesis and possible antiviral targets.

Overall, this thesis aims to shed light on broad-spectrum antiviral design, SARS- CoV-2 pathogenesis, potential therapeutic targets and host-virus interactions.

List of scientific papers

I. Andersson K, Azatyan A, Ekenberg M, Güçlüer G, Sardon Puig L, Pramer T, Puumalainen M, Monteil V, Mirazimi A. A CRISPR-Cas13b system degrades SARS-CoV and SARS-CoV-2 RNA in vitro. Viruses 2024;16(10):1539. https://doi.org/10.3390/v16101539

II. Husser C, Kwon H, Andersson K, Appelberg S, Montserrat N, Mirazimi A, Monteil VM. P53-Independent G1-Cell Cycle Arrest Increases SARS-CoV-2 RNA Replication. Microorganisms. 2024 Feb 22;12(3):443. https://doi.org/10.3390/microorganisms12030443