Chromatin Regulator SMARCA4 Is Essential for MHV-Induced Inflammatory Cell Death, PANoptosis

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• The innate immune system is crucial for defending against beta-coronaviruses (β-CoVs), including SARS-CoV-2.
• While essential for viral clearance, excessive innate immune activation and inflammatory cell death can lead to severe pathology like cytokine storm.
• PANoptosis, a specific inflammatory cell death pathway, is implicated in viral infection pathology.

Purpose of the Study:

• To identify host factors regulating inflammatory cell death during β-CoV infection.
• To understand the molecular mechanisms underlying PANoptosis triggered by β-CoVs.
• To explore potential therapeutic targets for mitigating β-CoV-induced disease severity.

Main Methods:

• Conducted a cell death-based CRISPR screen using mouse hepatitis virus (MHV), a β-CoV, as a trigger.
• Analyzed host molecules essential for inflammatory cell death.
• Utilized gRNA-mediated deletion of the identified gene in macrophages to assess its role in MHV-induced cell death.

Main Results:

• Identified SMARCA4, a chromatin regulator, as a host factor required for PANoptosis in response to MHV infection.
• Demonstrated that deletion of SMARCA4 significantly inhibited MHV-induced PANoptotic cell death in macrophages.
• Provided evidence for SMARCA4's role in regulating inflammatory cell death pathways during viral infection.

Conclusions:

• SMARCA4 is a critical host regulator of PANoptosis during β-CoV infection.
• Targeting SMARCA4 may represent a novel therapeutic strategy for treating β-CoV infections and associated inflammatory pathologies.
• Findings have potential clinical implications for advancing treatment strategies against β-CoVs and other viral infections.