A chromatin-regulated biphasic circuit coordinates IL1B-mediated inflammation
Inflammation is characterized by a biphasic cycle consisting initially of a pro-inflammatory phase which is subsequently resolved by anti-inflammatory processes. The coordination of these two disparate states needs to be highly controlled, suggesting that the regulation of the cytokines that drive these processes are intimately linked. Interleukin-1 beta (IL1B) is a master regulator of pro-inflammation and is encoded within the same topologically associated domain (TAD) as interleukin-37 (IL37). IL37 has recently emerged as a powerful anti-inflammatory cytokine which diametrically opposes the function of IL1B. Within this TAD, we identified a novel long non-coding RNA called AMANZI which negatively regulates IL1B expression and trained immunity through the induction of IL37 transcription. We found that the activation of IL37 occurs through the formation of a dynamic long-range chromatin contact that leads to the temporal delay of anti-inflammatory responses. The common variant rs16944 present in AMANZI augments this regulatory circuit, predisposing individuals to enhanced pro-inflammation or immunosuppression. Our work illuminates a chromatin-mediated biphasic circuit coordinating expression of IL1B and IL37, thereby regulating two functionally opposed states of inflammation from within a single TAD. Overall design: In order to investigate the functional role of the long noncoding RNA AMANZI, we depleted AMANZI RNA in THP-1 monocyte-like cells using locked nucleic acids (LNAs) in the gapmer configuration. THP-1 monocytes were activated by exposure to 10ng/ml of LPS for 24 hours prior to RNA extraction and library preparation.  The transcriptional profile of AMANZI knockdown were compared to a control LNA conditions in duplicate.