Abstract
ABSTRACT
Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease, but the contribution of long non‐coding RNAs (lncRNAs) to RSV‐induced epithelial–mesenchymal transition (EMT)‐associated changes remains unclear. We used transcriptomic screening in RSV‐exposed BEAS‐2B cells to identify candidate lncRNAs and then examined SRGAP2‐AS1 in cell and mouse models. Expression was measured by RT‐qPCR, and loss‐ and gain‐of‐function experiments were combined with RNA immunoprecipitation, co‐immunoprecipitation, Western blot analysis, and TCID
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assays. SRGAP2‐AS1 was increased in RSV‐infected BEAS‐2B cells and mouse lung tissue. Silencing SRGAP2‐AS1 reduced viral replication, lowered IL‐6 and IL‐1β mRNA, increased IFN‐β mRNA, and attenuated EMT‐associated marker changes in RSV‐infected BEAS‐2B cells. SRGAP2‐AS1 was predominantly cytoplasmic and enriched in PTBP1 immunoprecipitates. Reciprocal co‐immunoprecipitation showed that PTBP1 and ZEB1 were present in the same endogenous complex, and ZEB1 abundance changed with SRGAP2‐AS1 gain and loss of function. ZEB1 knockdown produced parallel changes in viral RNA, immune‐related transcripts, and EMT‐associated markers. Ectopic ZEB1 expression reversed the E‐cadherin change caused by SRGAP2‐AS1 depletion, supporting a downstream role for ZEB1 in the epithelial arm of the EMT‐associated phenotype. These findings support regulatory relationships among SRGAP2‐AS1, PTBP1, and ZEB1 during RSV infection. The causal order of the viral and immune‐related changes, and the in vivo relevance of the EMT‐associated phenotype, remain unresolved.