MALAT1-miR-20b-5p-P2RX7 Axis Regulates Mycobacterium bovis-Induced THP-1 Pyroptosis

Zoonotic tuberculosis (zoonotic TB) caused by Mycobacterium bovis (M. bovis) accounts for up to 10% of human tuberculosis cases in some regions, but the underlying pathogenic mechanisms remain incompletely understood, especially those involved in cellular pyroptosis. This study aimed to explore the regulatory roles of non-coding RNA (ncRNA) in the pyroptosis of human monocytic THP-1 cells induced by M. bovis infection. An in vitro pyroptosis model was established by infecting THP-1 cells with M. bovis, followed by whole-transcriptome sequencing to identify differentially expressed messenger RNA (mRNA), long non-coding RNA (lncRNA), microRNA (miRNA), and circular RNA (circRNA). Bioinformatics analysis was performed to construct an lncRNA-miRNA-mRNA regulatory network associated with infection-induced pyroptosis; in addition, overexpression, knockdown, and dual-luciferase reporter assays and quantitative PCR were conducted to verify the interactions and functions of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), miR-20b-5p, and purinergic receptor P2X7 (P2RX7). Transcriptome analysis detected 741 mRNAs, 1049 lncRNAs, 25 circRNAs, and 40 miRNAs with significant differential expression in infected THP-1 cells. Specifically, MALAT1 and P2RX7 were upregulated, while miR-20b-5p was downregulated after infection. Knockdown of MALAT1 or P2RX7 and overexpression of miR-20b-5p relieved M. bovis-induced pyroptosis in THP-1 cells. Mechanistically, MALAT1 targeted miR-20b-5p, which directly targeted P2RX7, and overexpression of miR-20b-5p partially reversed P2RX7 upregulation mediated by MALAT1 overexpression. This study provides a transcriptomic characterization of M. bovis-induced pyroptosis in THP-1 cells and supports the MALAT1-miR-20b-5p-P2RX7 axis as a potential regulatory mechanism involved in this process, offering initial molecular insights into the pathogenesis of zoonotic TB.