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

Area of Science:

• Immunology
• Microbiology
• Molecular Biology

Background:

• Zoonotic tuberculosis (zoonotic TB), caused by Mycobacterium bovis (M. bovis), represents a significant portion of human TB cases globally.
• The cellular mechanisms underlying M. bovis pathogenesis, particularly pyroptosis, are not fully understood.
• Non-coding RNAs (ncRNAs) are increasingly recognized for their roles in regulating cellular processes, including immune responses and cell death.

Purpose of the Study:

• To investigate the regulatory roles of ncRNAs in M. bovis-induced pyroptosis in human monocytic THP-1 cells.
• To identify key molecular players and construct a regulatory network involved in M. bovis infection-induced pyroptosis.
• To elucidate the specific interactions between MALAT1, miR-20b-5p, and P2RX7 in the context of M. bovis infection.

Main Methods:

• Establishment of an in vitro pyroptosis model using M. bovis-infected THP-1 cells.
• Whole-transcriptome sequencing to identify differentially expressed mRNA, lncRNA, miRNA, and circRNA.
• Bioinformatics analysis to construct regulatory networks; functional validation using overexpression, knockdown, dual-luciferase reporter assays, and quantitative PCR.

Main Results:

• Transcriptome analysis revealed significant differential expression of numerous mRNAs, lncRNAs, circRNAs, and miRNAs upon M. bovis infection.
• Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and purinergic receptor P2X7 (P2RX7) were upregulated, while miR-20b-5p was downregulated.
• Knockdown of MALAT1 or P2RX7, or overexpression of miR-20b-5p, attenuated M. bovis-induced pyroptosis; the MALAT1-miR-20b-5p-P2RX7 axis was confirmed.

Conclusions:

• This study provides a comprehensive transcriptomic profile of M. bovis-induced pyroptosis in human THP-1 cells.
• The identified MALAT1-miR-20b-5p-P2RX7 axis represents a crucial regulatory mechanism in M. bovis-induced pyroptosis.
• These findings offer novel molecular insights into the pathogenesis of zoonotic TB and potential therapeutic targets.