Thymelaea hirsuta (L.) Endl. extract attenuates NLRP3 inflammasome activation via modulation of ATPase activity

The NLRP3 inflammasome is a multiprotein complex of the innate immune system that mediates the maturation and secretion of interleukin-1β (IL-1β) and plays a pivotal role in the pathogenesis of chronic inflammatory diseases, including asthma, metabolic disorders, and autoimmune diseases. However, natural product-derived metabolites that directly modulate NLRP3 activation remain limited. This study aimed to investigate the inhibitory effects of Thymelaea hirsuta extract (TMH) on NLRP3 inflammasome activation and to elucidate its underlying mechanism of action.

TMH was prepared by methanol extraction and chemically profiled using UPLC-QTOF/MS analysis. Human monocytic THP-1 cells and murine macrophage J774A.1 cells were used to evaluate inflammasome activation. Following lipopolysaccharide (LPS) priming, cells were stimulated with ATP or nigericin to induce NLRP3 inflammasome activation. IL-1β secretion was quantified by ELISA, and the expression of NLRP3 inflammasome-related proteins was evaluated by Western blot analysis. Cell viability was assessed using the EZ-CYTOX assay.

TMH exhibited no cytotoxicity at concentrations up to 100 μg/mL. TMH treatment (10, 50, and 100 μg/mL) significantly reduced LPS/ATP- or LPS/nigericin-induced IL-1β secretion. However, even at the highest concentration tested (100 μg/mL), TMH did not significantly affect pro-IL-1β expression or NF-κB signaling, indicating that the priming step was not altered. Instead, TMH suppressed NLRP3 inflammasome activation during the activation phase. In addition, TMH treatment at 1 μg/mL was associated with reduced NLRP3 ATPase activity, suggesting a potential effect on inflammasome assembly.

TMH attenuated NLRP3 inflammasome activation without affecting the priming step. These findings suggest that TMH may act as a natural product-derived modulator of NLRP3-mediated inflammatory responses.