IFITM1 is a host restriction factor that inhibits porcine epidemic diarrhea virus infection.

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) infection and transmission pose a serious threat to the global swine industry. The search for a new host factor with anti-PEDV effect may be an effective potential target for the development of novel antiviral drugs. Interferon-induced transmembrane proteins (IFITMs) play a crucial role in the innate immune response triggered by viral infection, and it has been suggested that IFITMs can block the early stages of viral replication, but the mechanism of action is currently unclear. The current study sheds light on the role of IFITM1 in PEDV infection. Specifically, overexpression of IFITM1 suppresses PEDV proliferation in IPEC-J2 cells, while knockdown of IFITM1 has the opposite effect. Collectively, these findings underscore IFITM1's inhibitory role in PEDV infection, with critical implications for the residues and structural motifs within its CTD. RESULTS: The study demonstrates that IFITM1, an interferon-induced transmembrane protein, plays a critical role in the antiviral response against Porcine Epidemic Diarrhea Virus (PEDV). Notably: Overexpression of IFITM1 suppresses PEDV proliferation.IFITM1 co-localizes with PEDV virions in the cytoplasm surrounding the nucleus.Immunocolloidal gold electron microscopy reveals IFITM proteins embedded on the surface of PEDV virions.IFITM1 directly interacts with the N protein of PEDV.C-terminal domain mutations in IFITM1 compromise its inhibitory function against PEDV, with specific amino acid residues playing a pronounced role.These findings enhance our understanding of innate immunity and antiviral defense mechanisms, with potential implications for therapeutic strategies against PEDV infection. CONCLUSIONS: The study establishes IFITM1 as a key player in the antiviral response against PEDV. Its inhibitory function, co-localization with virions, and interaction with the N protein provide valuable insights. Notably, the CTD mutations of IFITM1 have a fundamental impact on its modulatory action. These findings contribute to our understanding of innate immunity and antiviral defense mechanisms, with potential implications for therapeutic strategies against PEDV infection.