Study on the differences in anti Mycobacterium tuberculosis infection between THP1 and U937 macrophages
Objective Investigating the differences of cellular transcriptome, cell death pathways, MAPK NFkB signaling pathways, and secretion of inflammatory cytokines in human macrophage cell lines THP1 and U937 during Mycobacterium tuberculosis infection, and to elucidate the differences between these two cell lines in Mycobacterium tuberculosis infection research. Methods THP1 and U937 cell lines were differentiated into macrophages using Phorbol 12 myristate 13 acetate (PMA). THP1 and U937 macrophages were infected with Mycobacterium tuberculosis H37Rv at a multiplicity of infection (MOI) of 5. Cells or culture supernatants were collected at indicated times, and experimental methods, including RNA sequencing (RNAseq), western blotting, enzyme linked immunosorbent assay (ELISA), and colony forming unit counting (CFU counting) were employed to detect the transcriptome, levels of specific marker molecules, and the intracellular survival of Mycobacterium tuberculosis respectively. Results the intracellular survival of Mycobacterium tuberculosis within THP1 and U937 macrophages were increased 4.65 0.14 times and 1.83 0.12 times respectively at 72 hours postinfection in comparison to that of their corresponding controls. Significant differences of cellular transcriptome was observed between Mycobacterium tuberculosis infected THP1 and U937 macrophages. Mycobacterium tuberculosis-infected THP1 macrophages showed significantly higher levels of Cleaved caspase1, Cleaved caspase3, and N GSDMD, and significantly lower levels of Gpx4, LC3B, piRIP3, and piMLKL respectively compared to that of U937 macrophages at 24 and 48 hours post-infection. Mycobacterium tuberculosis-infected THP1macrophages showed significantly lower levels of pip38 but significantly higher levels of piJNK, piERK, and pip65 respectively compared to that of U937 macrophages at indicated times. Additionally, the levels of IL1b, IL6, and TNFa in the culture supernatant from Mycobacterium tuberculosis-infected U937 macrophages were significantly higher than those in THP1 macrophages. Conclusions Significant differences in responding to Mycobacterium tuberculosis infection and triggering associated immune reactions were found between THP1 and U937 macrophages.