Epitranscriptomic N6-Methyladenosine Profile of SARS-CoV-2-Infected Human Lung Epithelial Cells

Posttranscriptional modification of viral and cellular RNA by N-6-methyladenosine (m(6)A) plays an important role in regulating the replication of many viruses and the cellular immune response to infection. We therefore sought to define the epitranscriptomic m(6)A profile of human lung epithelial cells infected with SARS-CoV-2. N-6-methyladenosine (m(6)A) is a dynamic posttranscriptional RNA modification that plays an important role in determining transcript fate. The functional consequence of m(6)A deposition is dictated by a group of host proteins that specifically recognize and bind the m(6)A modification, leading to changes in RNA stability, transport, splicing, or translation. The cellular m(6)A methylome undergoes changes during certain pathogenic conditions such as viral infections. However, how m(6)A modification of host cell transcripts and noncoding RNAs change during severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection has not been reported. Here, we define the epitranscriptomic m(6)A profile of SARS-CoV-2-infected human lung epithelial cells compared to uninfected controls. We identified mRNA and long and small noncoding RNA species that are differentially m(6)A modified in response to SARS-CoV-2 infection. The most significantly differentially methylated transcript was the precursor of microRNA-4486 (miRNA-4486), which showed significant increases in abundance and percentage of methylated transcripts in infected cells. Pathway analyses revealed that differentially methylated transcripts were significantly associated with several cancer-related pathways, protein processing in the endoplasmic reticulum, cell death, and proliferation. Upstream regulators predicted to be associated with the proteins encoded by differentially methylated mRNAs include several proteins involved in the type-I interferon response, inflammation, and cytokine signaling.IMPORTANCE Posttranscriptional modification of viral and cellular RNA by N-6-methyladenosine (m(6)A) plays an important role in regulating the replication of many viruses and the cellular immune response to infection. We therefore sought to define the epitranscriptomic m(6)A profile of human lung epithelial cells infected with SARS-CoV-2. Our analyses demonstrate the differential methylation of both coding and noncoding cellular RNAs in SARS-CoV-2-infected cells compared to uninfected controls. Pathway analyses revealed that several of these RNAs may be involved in the cellular response to infection, such as type-I interferon. Our study implicates m(6)A modification of infected-cell RNA as a mechanism of posttranscriptional gene regulation during SARS-CoV-2 infection.

Automated summary

Posttranscriptional modification of viral and cellular RNAs by N-6-methyladenosine (m(6)A) is important in regulating virus replication and cellular immune response. This study analyzed the m(6)A profile of human lung epithelial cells infected with SARS-CoV-2, and found differential methylation of mRNA and noncoding RNA. These modifications may have important functions in the cellular response to infection.