Relation between microRNA-155 and inflammatory mediators in multiple sclerosis

Area of Science:

• Neuroscience
• Immunology
• Genetics

Background:

• Multiple sclerosis (MS) is a chronic autoimmune disease impacting the central nervous system, characterized by neuroinflammation, demyelination, and axonal damage.
• MicroRNA-155 (miRNA-155) is recognized as a key pro-inflammatory regulator in macrophages and microglia, influencing their functional polarization.

Purpose of the Study:

• To investigate the plasma levels of miRNA-155 in patients with relapsing-remitting multiple sclerosis (RRMS).
• To evaluate the association between miRNA-155 levels and key inflammatory and anti-inflammatory mediators in RRMS.

Main Methods:

• The study involved 60 MS patients and 30 healthy controls.
• Real-time quantitative polymerase chain reaction (RT-qPCR) was used to measure miRNA-155, iNOS, and SMAD2.
• Enzyme-linked immunosorbent assay (ELISA) was employed to quantify TNF-α, IFN-ɣ, TGF-β, and IL-10 levels.

Main Results:

• No significant differences in miRNA-155, SMAD2, or iNOS expression were found between MS patients and controls.
• A statistically significant increase in TNF-α, IFN-ɣ, and TGF-β levels was observed in MS patients.
• IL-10 levels did not show significant differences between the groups.
• Significant positive correlations were found between miRNA-155 and TNF-α, IFN-ɣ, and iNOS.
• Inverse correlations were observed between miRNA-155 and IL-10, TGF-β, and SMAD2.

Conclusions:

• Plasma miRNA-155 expression in MS patients correlates positively with pro-inflammatory markers (TNF-α, IFN-ɣ, iNOS) and negatively with anti-inflammatory markers (IL-10, TGF-β, SMAD2).
• These findings suggest that miRNA-155 may play a role in modulating macrophage and microglia polarization in MS, potentially by influencing the secretion of these mediators.