R.I flagellin decreases NLRP3 inflammasome activation and pyroptosis in THP-1 macrophages. RT-qPCR analysis was performed to determine mRNA expression levels of (A) NLRP3 and (B) ASC. (C) Western blot analysis was performed to determine the protein expression levels of (D) NLRP3, (E) ASC, (F) cleaved caspase-1 and (G) GSDMD-N in THP-1 macrophages. (H) RT-qPCR analysis was performed to determine IL-1β mRNA expression in THP-1 macrophages. (I) IL-1β levels in the culture medium were detected via the enzyme-linked immunosorbent assay. (J) Representative electron micrographs of treated THP-1 macrophages (magnification, ×20,000). Red arrowheads indicate membrane pores. Data are presented as the mean ± standard error of the mean (n=3/group). *P<0.05 vs. control group; #P<0.05 vs. LPS+ATP group. R.I, Roseburia intestinalis; NLRP3, nucleotide-binding oligomerization segment-like receptor family 3; RT-qPCR, reverse transcription-quantitative PCR; ASC, apoptosis-associated speck-like protein; GSDMD-N, Gasdermin D N-terminal fragment; IL, interleukin.