Gene Expression Analysis of Murine Primary Microglia Stimulated with LPS using Microarray

Background: Since heightened microglial activation was shown to play a role in the pathogenesis of many brain disorders, understanding the molecular mechanisms of microglial activation may lead to new treatment strategies. The microarray system permitted screening of large numbers of genes in biological or pathological processes. Therefore, we evaluated the gene expression pattern during microglial activation using microarray analysis. Methods: Primary microglial cultures were prepared from postnatal Swiss Webster mice. The cells were activated by lipopolysaccharide (LPS, 10 µg/ml) for 5 hours prior to cell harvesting. From the cultured cells, we isolated mRNA, synthesized cDNA, converted to biotinylated cRNA and then reacted with GeneChips (Affymetrix MU74A-v2). The data were normalized and analyzed. Results: After microglial activation with LPS, we found>4 fold increases in the expression of 139 genes and>4 fold decreases of 16 genes expression compared with control. Most of the induced or suppressed genes were known to regulate inflammation, immune reactions, injury responses, cell death or survival related mechanisms. Conclusions: These results suggest that microarray analysis of gene expression may be useful for screening novel molecular mediators of microglial activation and making profound understanding of the cellular mechanisms as a whole. Such screening techniques should provide insights into the molecular basis of brain disorders and hel