Exploring the Role of Guanylate-Binding Protein-2 in Activated Microglia-Mediated Neuroinflammation and Neuronal Damage

Neuron damage by microglia, which act as macrophage cells in the brain, can result in various brain diseases. However, the function of pro-inflammatory or anti-inflammatory microglia in the neurons remains controversial. Guanylate-binding protein-2 (GBP2) is expressed and activated in the microglia in the early phase of the inflammatory response and plays an important role in controlling immune responses. In this study, we evaluated whether GBP2 initially reduces the immune response induced by microglia, and whether microglia induce pro-inflammatory functions in neurons via GBP2 expression. In lipopolysaccharide (LPS)-stimulated microglia, we assessed the expression of GBP2 and how it affects neurons via activated microglia. The biological functions of microglia due to the downregulation of the GBP2 gene were examined using short hairpin RNA (shRNA)-RNA-GBP2. Downregulated GBP2 affected the function of mitochondria in the microglia and showed reduced neuronal damage when compared to the control group in the co-culture system. Furthermore, this protein was observed to be highly expressed in the brains of dementia mice. Our results are the first to report that the downregulation of GBP2 in activated microglia has an anti-inflammatory function. This study suggests that the GBP2 gene can be used as a therapeutic target biomarker for inflammation-related neurodegenerative diseases.