# Systematic Identification of the Functional lncRNAs During H7N9 Avian Influenza Virus Infection in Mice

## TL;DR

This study identifies functional long non-coding RNAs (lncRNAs) involved in H7N9 avian influenza virus infection in mice, revealing their roles in immune responses and antiviral activity.

## Contribution

The study systematically identifies lncRNAs associated with IAV virulence in mice and highlights two lncRNAs with antiviral effects.

## Key findings

- 7636 differentially expressed lncRNAs were identified in S8-infected mice compared to controls.
- Two lncRNAs, NONMMUG032982.2 and NONMMUG032328.2, showed strong antiviral activity against IAV.
- Target mRNAs were enriched in immunological processes and inflammatory signaling pathways.

## Abstract

Accumulating studies have identified the pivotal role of long non-coding RNAs (lncRNAs) in participating in host–virus interactions during virus infections. However, the regulatory roles of lncRNAs in influenza A virus (IAV) infection are still not fully elucidated. In this study, using high-throughput sequencing, we comprehensively compared the expression profiles of lncRNAs and mRNAs in mouse lungs infected either with the nonpathogenic parental (SDL124) H7N9 virus or its moderately pathogenic mouse-adapted (S8) variant. A total of 7636 significantly differentially expressed (SDE) lncRNAs were obtained in the S8-infected group compared to the mock group. As for the SDL124 group, 1042 SDE lncRNAs were identified. Subsequently, the mRNAs co-expressed with SDE lncRNAs were subjected to functional annotation and pathway enrichment analysis. The results indicated that the target mRNAs regulated by the S8 virus were mainly enriched in various immunological processes and exhibited a strong correlation with inflammatory-related signaling pathways. Moreover, 12 lncRNAs and 10 mRNAs co-expressed with SDE lncRNAs were selected and successfully verified by RT-qPCR. Among these lncRNAs, NONMMUG032982.2 and NONMMUG032328.2 exhibited strong antiviral activity against IAV. Additionally, these two lncRNAs were chosen for further in-depth bioinformatics analysis, including transcription factor prediction, coding capacity assessment, genomic location, construction of secondary structure, and prediction of potential interacting proteins. Taken together, these findings provide a cluster of lncRNAs probably associated with the virulence of IAV in mice and shed light on the anti-IAV effects of two functional lncRNAs, establishing a molecular foundation for further exploring the regulatory mechanisms of lncRNAs in IAV infection.