Microarray analysis of gene expression profile by treatment of Cinnamomi Ramulus in lipopolysaccharide-stimulated BV-2 cells.

It has been reported that components of Cinnamomi Ramulus (CR) demonstrate an anti-inflammatory effect by inhibiting the expression of inducible nitric oxide synthesis (iNOS) and cyclooxygenase-2 (COX-2) and by suppressing nitric oxide (NO) production in the central nervous system (CNS) as well as in the periphery. In this study, microarray analysis was performed to investigate the effect of CR on the gene expression and associated pathways of lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Microglia plays an important role in the processes of several inflammation-mediated neurodegenerative diseases. Activated microglia can produce various pro-inflammatory cytokines, chemokines, and toxic mediators, which may initiate or amplify the inflammatory responses in the CNS. In the present study, the negative control group was cultured in normal medium, the positive control group was activated with 1 microg/ml of LPS, and the CR group was previously treated with 10 microg/ml of CR before LPS stimulation. With the cutoff value of 1.5-fold change in the expression, 341 genes including pro-inflammatory cytokines, chemokines, and transcription factors were found to be up-regulated in LPS-stimulated BV-2 cells (Supplemental Table 2). CR reduced the LPS-induced up-regulation of such inflammatory genes as Ccl5, Cd80, Cxcl10, Grin2a, Ifi203, Ifit1, Il1alpha, Il6, Lilrb3, Nos2 (iNOS), Rab2b, Rsad2 and Vpreb1. This resulted in a full list of 38 and 37 annotated genes whose expression is up- and down-regulated by CR respectively (Supplemental Table 3). RT-PCR analysis showed that the expression of LPS-induced TNF-alpha, IL-1beta, IL-6, and iNOS mRNAs were attenuated in the presence of the CR extract. The results imply that CR has the anti-inflammatory effect of down-regulating the expression of various genes related to inflammatory responses in LPS-stimulated BV-2 cells, and that CR could be a candidate for the prevention or therapeutic treatment of inflammation-mediated neurodegenerative diseases.