Investigating the Molecular Response of Microglia to Lipopolysaccharide-induced Neurotropic Activation: Implications for Blood-Brain Barrier Breakdown

We investigated the molecular response of microglia, a key player in brain defense, to neurotropic activation by lipopolysaccharide. We found increased expression of pro-inflammatory and regulatory signaling markers and the blood-brain barrier (BBB) breakdown. Specifically, we observed significant increases in TNF-α (>4-fold) and IL-1β (>8-fold), which indicate inflammation, and IL-6 and MCP-1 signal leukocyte recruitment and infiltration. We also saw an increase in MMP-2 expression and a decrease in Occludin expression, showing BBB breakdown. However, we found no changes in MMP-9 or its inhibitor TIMP-1. Our study is the first to uncover the molecular mechanisms of early immune response and its effect on barrier proteins of the microglial cell and will be useful for understanding the brain’s immune response to infectious diseases.