[Overexpression of miR-125b promotes apoptosis of macrophages]

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Pulmonary tuberculosis (PTB) is a significant global health concern, particularly in pediatric populations.
• MicroRNAs (miRNAs) play crucial roles in regulating immune responses and cellular processes.
• Dysregulation of specific miRNAs, like miR-125b, may contribute to the pathogenesis of PTB.

Purpose of the Study:

• To investigate the expression levels of miR-125b and its target gene, Raf1 proto-oncogene serine/threonine protein kinase (RAF1), in pediatric PTB patients.
• To elucidate the regulatory role of miR-125b on macrophage apoptosis and activity in the context of PTB.

Main Methods:

• Peripheral blood mononuclear cells (PBMCs) were collected from pediatric PTB patients and healthy controls.
• Real-time fluorescence quantitative PCR and Western blotting were employed to quantify miR-125b, RAF1 mRNA, and RAF1 protein levels.
• THP-1 macrophages were manipulated with miR-125b mimics and inhibitors to assess effects on RAF1 expression, apoptosis (via annexin V-FITC/PI staining and flow cytometry), and proliferation (via CCK-8 assay).

Main Results:

• miR-125b expression was significantly downregulated in PBMCs of pediatric PTB patients.
• Conversely, both mRNA and protein levels of RAF1 were upregulated in pediatric PTB patients.
• Overexpression of miR-125b in THP-1 macrophages reduced RAF1 expression, induced apoptosis, and decreased cell activity.
• Inhibition of miR-125b led to elevated RAF1 expression, suppressed apoptosis, and enhanced cell activity.

Conclusions:

• Pediatric PTB is associated with low levels of miR-125b in PBMCs.
• miR-125b negatively regulates RAF1 expression in macrophages.
• Upregulating miR-125b demonstrates therapeutic potential by promoting macrophage apoptosis and inhibiting cellular activity, suggesting a role in controlling PTB progression.