Betamethasone Dipropionate Inhibits NLRP3 Inflammasome Activation by Suppressing Pro-IL-1β Expression

The NOD-like receptor Family, pyrin domain-containing 3 protein (NLRP3) inflammasome is a macromolecular complex critical for inflammatory responses. Its excessive activation or improper regulation is intimately associated with the development of various inflammatory diseases. However, currently available drugs directly targeting the NLRP3 inflammasome are limited. In preliminary analyses, detecting the level of secreted interleukin-1 beta (IL-1β) revealed that betamethasone-17,21-dipropionate (also known as betamethasone dipropionate, BD), a clinically used glucocorticoid, potentially inhibits NLRP3 inflammasome activation.

In vitro, the role and preliminary mechanism of BD in inhibiting the activation of NLRP3 inflammasome were investigated in THP-1-differentiated macrophages and bone marrow-derived macrophages (BMDMs) using enzyme-linked immunosorbent assay (ELISA), Cell Counting Kit-8 (CCK-8), reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blotting (WB). The preliminary effects of BD on the assembly of NLRP3 inflammasome were assessed in HEK293T cells overexpressing NLRP3/ASC/caspase-1/NEK7 through drug affinity responsive target stability (DARTS) and co-immunoprecipitation (Co-IP) approaches. In vivo, the effect of BD on LPS-induced systemic inflammation was assessed by measuring serum concentrations of IL-1β and TNF-α via ELISA, and by recording mouse survival rates and body weights.

BD significantly inhibited NLRP3 inflammasome activation by suppressing pro-IL-1β expression in vitro. Mechanistic studies showed that it decreased pro-IL-1β expression by suppressing NF-κB signaling. In vivo, BD downregulated the serum concentrations of IL-1β and TNF-α, and increase the survival rate of mice using the LPS-induced systemic inflammation model.

Collectively, our data verify that BD inhibits NLRP3 inflammasome activation by suppressing pro-IL-1β expression. These findings suggest that BD may be a potential therapeutic approach for inflammatory diseases. However, further studies are needed to elucidate its precise role and specific mechanism in clinical practice.