Mechanism of Vaginal Epithelial Cell Pyroptosis Induced by the NLRP3 Inflammasome in Vulvovaginal Candidiasis.

PROBLEM: Vulvovaginal candidiasis (VVC) is a common mucosal fungal infection, and Candida albicans is the main causative agent. The NLRP3 inflammasome plays an important role in VVC, but the underlying mechanism is unknown. METHOD OF STUDY: Vaginal epithelial cells were divided into three groups: control, C. albicans strain SC5314 (wild-type, WT), and WT+ Matt Cooper Compound 950 (MCC950, a specific NLRP3 inhibitor). After human vaginal epithelial cells were pretreated with 1 µmol/L MCC950 for 2 h, C. albicans (MOI = 1) was cocultured with the human vaginal epithelial cells for 12 h. The cell supernatants were collected, LDH was detected, and the IL-1ß and IL-18 levels were determined by ELISA. The expression of the pyroptosis-related proteins NLRP3, Caspase-1 p20 and GSDMD was measured by Western blotting analysis. The protein expression of the pyroptosis-related N-terminus of GSDMD (GSDMD-N) was detected by immunofluorescence. RESULTS: In this study, we showed that the WT C. albicans strain induced pyroptosis in vaginal epithelial cells, as indicated by the LDH and proinflammatory cytokine levels and the upregulated levels of the pyroptosis-related proteins NLRP3, Caspase-1 p20, and GSDMD-N. MCC950 reversed the changes in the expression of these proteins and proinflammatory cytokines in vaginal epithelial cells. CONCLUSION: C. albicans activated the NLRP3 inflammasome to induce vaginal epithelial cell pyroptosis. MCC950 inhibited the NLRP3 inflammasome, reduced vaginal epithelial cell pyroptosis, and decreased the release of inflammatory cytokines.

Synthesis of folate­chitosan nanoparticles loaded with ligustrazine to target folate receptor positive cancer cells.

In addition to its vasodilatory effect, ligustrazine (LZ) improves the sensitivity of multidrug resistant cancer cells to chemotherapeutic agents. To enhance the specificity of LZ delivery to tumor cells/tissues, folate­chitosan nanoparticles (FA­CS­NPs) were synthesized by combination of folate ester with the amine group on chitosan to serve as a delivery vehicle for LZ (FA­CS­LZ­NPs). The structure of folate­chitosan and characteristics of FA­CS­LZ­NPs, including its size, encapsulation efficiency, loading capacity and release rates were analyzed. MCF­7 (folate receptor­positive) and A549 (folate receptor­negative) cells cultured with or without folate were treated with FA­CS­LZ­NPs, CS­LZ­NPs or LZ to determine cancer­targeting specificity of FA­CS­LZ­NPs. Fluorescence intensity of intracellular LZ was observed by laser scanning confocal microscopy, and concentration of intracellular LZ was detected by HPLC. The average size of FA­CS­LZ­NPs was 182.7±0.56 nm, and the encapsulation efficiency and loading capacity was 59.6±0.23 and 15.3±0.16% respectively. The cumulative release rate was about 95% at pH 5.0, which was higher than that at pH 7.4. There was higher intracellular LZ accumulation in MCF­7 than that in A549 cells and intracellular LZ concentration was not high when MCF­7 cells were cultured with folate. These results indicated that the targeting specificity of FA­CS­LZ­NPs was mediated by folate receptor. Therefore, the FA­CS­LZ­NPs may be a potential folate receptor­positive tumor cell targeting drug delivery system that could possibly overcome multidrug resistance during cancer therapy.