MiR-146a Ameliorates Hemoglobin-Induced Microglial Inflammatory Response via TLR4/IRAK1/TRAF6 Associated Pathways

Area of Science:

• Neuroscience
• Immunology
• Molecular Biology

Background:

• Microglial activation and sustained brain inflammation contribute to neuronal damage in central nervous system diseases.
• Limiting neuroinflammation is a key therapeutic strategy for these conditions.
• MicroRNA-146a (miR-146a) is recognized for its role in negatively regulating inflammatory responses.

Purpose of the Study:

• To investigate miR-146a expression changes following subarachnoid hemorrhage (SAH) induction.
• To assess the anti-inflammatory effects of miR-146a in microglial cells.
• To explore miR-146a's potential as a therapeutic agent for brain inflammation.

Main Methods:

• Experimental induction of SAH in vivo and in vitro.
• Primary microglial cells were treated with miR-146a prior to hemoglobin (Hb) exposure.
• Analysis of pro-inflammatory cytokine gene expression (TNF-α, IL-1β) and microglial phenotype markers (iNOS, CD86) via signaling pathways (IRAK1/TRAF6/NF-κB, MAPK).

Main Results:

• miR-146a treatment reduced Hb-induced gene expression of pro-inflammatory cytokines (TNF-α, IL-1β) and phenotype markers (iNOS, CD86) in microglial cells.
• These effects were mediated through the IRAK1/TRAF6/NF-κB or MAPK signaling pathways.
• Unlike LPS-induced activation, miR-146a levels did not increase following SAH-induced microglial activation.

Conclusions:

• miR-146a exhibits pro-resolution activity in microglia, playing a regulatory role in brain inflammation.
• Findings suggest miR-146a is a potential novel therapeutic agent for treating brain inflammation and associated central nervous system diseases.