ADAR1-mediated RNA editing promotes B cell lymphomagenesis.

The project aims to evaluate the contribution of ADAR1 RNA editing to B cell lymphomagenesis, specifically in diffuse large B cell lymphoma (DLBCL). Within our DLBCL cohort, RNA editing targets transcripts within known lymphoma-driving pathways such as apoptosis, p53 and NF-kB signaling, as well as the previously unrecognized RIG-I-like pathway. In the latter context, we show that ADAR1-mediated editing in the MAVS transcript correlates with increased MAVS protein expression levels, associating with increased interferon/NF-kB signaling and increased T cell exhaustion. To confirm this mechanism, we have performed LC-MSMS analysis on a DLBCL cell line (RCK8) in the presence or absence of ADAR1 (Figure S11D ). Additionally, using targeted RNA base editing tools to restore editing within MAVS 3'UTR in ADAR1-deficient cells, we demonstrate that editing is likely to be causal to an increase in downstream signaling in the absence of activation by canonical nucleic acid receptor sensing. To confirm that this signaling increase depends on an increase of MAVS protein upon specific editing, we have performed LC-MSMS analysis on the same samples (Figure 4G).