BC-1215 inhibits ATP-induced IL-1β secretion via the FBXL2-mediated ubiquitination and degradation of not only NLRP3, but also pro-IL-1β in LPS-primed THP-1 cells

by Selleckchem | May 10 2023

BC-1215, bis-pyridinyl benzyl ethanediamine, is an inhibitor of F-box only protein 3 (FBXO3) and exerts anti-inflammatory effects. BC-1215 inhibits interactions between FBXO3-F-box and the leucine rich repeat protein 2 (FBXL2), leading to the upregulation of FBXL2 expression, FBXL2-mediated ubiquitination and the degradation of tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) or NOD-, LRR- and the pyrin domain-containing protein 3 (NLRP3), which subsequently results in the down-regulation of inflammatory cytokine production. In the current study, we investigated the issue of whether or how BC-1215 suppresses the ATP-induced secretion of IL-1β in LPS-primed human macrophage-like cells, THP-1 cells. Our result show that pre-treatment with BC-1215 attenuated the ATP-induced secretion of IL-1β in LPS-primed THP-1 cells. Treatment of the LPS-primed THP-1 cells with BC-1215 resulted in a decrease in the level of NLRP3 and pro-IL-1β at the protein level, but not at the mRNA level. In addition, treatment with MG-132, but not leupeptin, inhibited the BC-1215-induced degradation of NLRP3 and pro-IL-1β proteins, and restored their levels, suggesting that BC-1215 decreases the stability of NLRP3 and pro-IL-1β at the protein level via proteasome-dependent degradation. Our results also show that FBXL2, which is increased by BC-1215, bound to and ubiquitinated NLRP3 and pro-IL-1β, but not pro-caspase-1. These collective results indicate that treatment with BC-1215, an inhibitor of FBXO3, inhibits ATP-induced IL-1β secretion via the FBXL2-mediated ubiquitination and degradation of pro-IL-1β as well as NLRP3 in LPS-primed THP-1 cells, suggesting that FBXO3 is a potential therapeutic target for developing agents against inflammatory diseases.

Comments:

The study investigated the effect of BC-1215, an inhibitor of FBXO3, on the secretion of IL-1β in LPS-primed THP-1 cells stimulated with ATP. The results showed that pre-treatment with BC-1215 attenuated the ATP-induced secretion of IL-1β in LPS-primed THP-1 cells. Further investigation revealed that BC-1215 decreased the stability of NLRP3 and pro-IL-1β proteins, leading to their degradation via proteasome-dependent mechanisms.

Interestingly, treatment with BC-1215 also upregulated the expression of FBXL2, which bound to and ubiquitinated NLRP3 and pro-IL-1β, but not pro-caspase-1. These findings suggest that FBXO3 is a potential therapeutic target for developing agents against inflammatory diseases, as BC-1215 can inhibit ATP-induced IL-1β secretion via FBXL2-mediated ubiquitination and degradation of NLRP3 and pro-IL-1β in LPS-primed THP-1 cells.

Overall, the study provides insights into the molecular mechanism underlying the anti-inflammatory effects of BC-1215 and suggests that targeting FBXO3 could be a promising strategy for developing novel anti-inflammatory agents.