ESAT-6 Modulates Macrophage Apoptosis in Mycobacterium Tuberculosis via lncNEAT1/miR-125b-5p/TNF-α Pathway

Area of Science:

• Immunology
• Molecular Biology
• Microbiology

Background:

• Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a major global health concern.
• Mtb utilizes secretory proteins like Early secreted antigenic target 6 kDa (ESAT-6) to evade host immunity and promote infection.
• The precise mechanism by which ESAT-6 induces macrophage apoptosis, aiding Mtb dissemination, remains unclear.

Purpose of the Study:

• To elucidate the molecular mechanism underlying ESAT-6-induced macrophage apoptosis.
• To investigate the role of Long non-coding RNA nuclear enriched abundant transcript 1 (lncNEAT1) in this process.
• To identify potential therapeutic targets for TB treatment.

Main Methods:

• Human monocytic leukemia (THP-1) cells were differentiated into macrophages.
• Recombinant ESAT-6 was used to induce apoptosis, assessed by Annexin V-FITC/propidium iodide staining and flow cytometry.
• Small interfering RNA (siRNA) was employed to silence lncNEAT1 expression.
• RT-qPCR and Western blot were used to quantify gene and protein expression (lncNEAT1, miR-125b-5p, TNF-α).
• Bioinformatics and luciferase reporter assays explored regulatory mechanisms.

Main Results:

• ESAT-6 induced macrophage apoptosis in a dose-dependent manner.
• ESAT-6 upregulated lncNEAT1 expression.
• lncNEAT1 was found to target miR-125b-5p, which in turn targets the 3'UTR of TNF-α mRNA.
• Inhibition of lncNEAT1 attenuated ESAT-6-induced apoptosis by modulating the miR-125b-5p/TNF-α axis.

Conclusions:

• ESAT-6 triggers macrophage apoptosis through the lncNEAT1/miR-125b-5p/TNF-α pathway.
• This pathway represents a novel mechanism of Mtb virulence.
• Targeting the lncNEAT1/miR-125b-5p/TNF-α axis offers a potential therapeutic strategy for TB.