Abstract: Objective To explore the effect of dihydroartemisinin (DHA) on LL-37-induced pyroptosis in human keratinocyte HaCaT cells. Methods HaCaT cells were divided into control group, model group(40 μg/mL LL-37), DHA low-dose group(DHA-L,40 μg/mL LL-37+10 μmol/L DHA), DHA medium-dose group(DHA-M, 40 μg/mL LL-37+25 μmol/L DHA) and DHA high-dose group (DHA-H,40 μg/mL LL-37+50 μmol/L DHA)and cultured for 48 hours after adding the corresponding reagents. Cell pyroptosis was detected by flow cytometry. Levels of IL-1βand IL-18 in cell supernatant were measured by enzyme-linked immunosorbent assay (ELISA). and the protein expressions of NOD-like receptor pyrin domain containing 3 (NLRP3), active caspase-1, gasdermin D-N(GSDMD-N) were detected with Western blot. Results Compared with the control group, the cell pyroptosis rate, the levels of IL-1β and IL-18, and the expression levels of NLRP3, active caspase-1, and GSDMD-N proteins were significantly increased in model group (P＜0.05); Compared with the model group, the cell pyroptosis rate was significantly reduced (P＜0.05) in DHA-L, DHA-M and DHA-H group; the levels of IL-1 β and IL-18, the protein expression of NLRP3, active caspase-1, and GSDMD-N were significantly decreased in DHA-L, DHA-M and DHA-H group (P＜0.05). Conclusions DHA attenuates LL-37-induced pyroptosis and inflammatory responses in HaCaT cells in a dose-dependent manner. This effect is potentially associated with the modulation of NLRP3 inflammasome-related protein expression, suggesting that DHA may possess promising anti-inflammatory properties.

Key words: rosacea, dihydroartemisinin, antimicrobial peptide, NLRP3, pyroptosis