The SMARCA4-TMEM47 axis plays an essential role in chikungunya virus RNA replication

Area of Science:

• Virology
• Molecular Biology
• Immunology

Background:

• Chikungunya virus (CHIKV) presents a significant global public health challenge.
• Identifying host factors essential for CHIKV replication is crucial for therapeutic development.

Purpose of the Study:

• To identify host factors involved in the CHIKV life cycle.
• To investigate the role of the cBAF complex subunit SMARCA4 and its downstream targets in CHIKV infection.
• To explore the SMARCA4-TMEM47 axis as a potential therapeutic target against CHIKV.

Main Methods:

• Utilized cell-based assays to identify host factors for CHIKV.
• Investigated the function of SMARCA4 and TMEM47 in CHIKV replication using knockdown and expression studies.
• Performed co-immunoprecipitation and microscopy to analyze protein-RNA interactions and cellular localization.
• Evaluated the efficacy of SMARCA4 inhibitors in CHIKV-infected cells and mice.

Main Results:

• Identified SMARCA4, a core ATPase subunit of the cBAF complex, as a host factor essential for CHIKV replication.
• Demonstrated that SMARCA4 facilitates the expression of the transmembrane protein TMEM47.
• Showed that TMEM47 deficiency impairs CHIKV replication in vitro and reduces viral load and pathology in vivo.
• Revealed that TMEM47 interacts with CHIKV RNA and nsP1, and is required for viral replication spherule assembly.
• Confirmed that SMARCA4 inhibitors effectively inhibit CHIKV replication.

Conclusions:

• The SMARCA4-TMEM47 pathway is critical for the CHIKV life cycle.
• TMEM47 acts as a key host factor, mediating viral RNA and nsP1 interactions for replication.
• Targeting the SMARCA4-TMEM47 axis presents a viable therapeutic strategy for Chikungunya virus infection.