Whole-genome CRISPR screen identifies RAVER1 as a key regulator of RIPK1-mediated inflammatory cell death, PANoptosis

Transforming growth factor-beta-activated kinase 1 (TAK1) is a central regulator of innate immunity, cell death, inflammation, and cellular homeostasis. Therefore, many pathogens carry TAK1 inhibitors (TAK1i). As a host strategy to counteract this, inhibition or deletion of TAK1 induces spontaneous inflammatory cell death, PANoptosis, through the RIPK1-PANoptosome complex, containing the NLRP3 inflammasome and caspase-8/FADD/RIPK3 as integral components; however, PANoptosis also promotes pathological inflammation. Therefore, understanding molecular mechanisms that regulate TAK1i-induced cell death is essential. Here, we report a genome-wide CRISPR screen in macrophages that identified TAK1i-induced cell death regulators, including polypyrimidine tract-binding (PTB) protein 1 (PTBP1), a known regulator of RIPK1, and a previously unknown regulator RAVER1. RAVER1 blocked alternative splicing of Ripk1, and its genetic depletion inhibited TAK1i-induced, RIPK1-mediated inflammasome activation and PANoptosis. Overall, our CRISPR screen identified several positive regulators of PANoptosis. Moreover, our study highlights the utility of genome-wide CRISPR-Cas9 screens in myeloid cells for comprehensive characterization of complex cell death pathways to discover therapeutic targets.

Automated summary

Transforming growth factor-beta-activated kinase 1 (TAK1) is a central regulator of innate immunity, cell death, inflammation, and cellular homeostasis. Many pathogens carry TAK1 inhibitors (TAK1i), but inhibition or deletion of TAK1 induces spontaneous inflammatory cell death, PANoptosis, which promotes pathological inflammation. Therefore, understanding the molecular mechanisms that regulate TAK1i-induced cell death is crucial.