The attenuating effects of 1,2,3,4,6 penta-O-galloyl-β-D-glucose on pro-inflammatory responses of LPS/IFNγ-activated BV-2 microglial cells through NFkB and MAPK signaling pathways

Background. Overactivated microglial cells exhibit chronic inflammatory response and can lead to the continuous production of pro-inflammatory cytokines, perpetuating inflammation, and ultimately resulting in neuronal injury. 1,2,3,4,6-Penta-O-Galloyl-beta-D-Glucose (PGG), which is a naturally occurring polyphenolic compound, has exhibited anti-inflammatory effect through the inhibition of many cytokines in different experimental models, but its effect on activated microglia cells was never described. In the present study, we investigated PGG effect in proteins involved in the NFkB and MAPK signaling pathways, which play a central role in inflammation through their ability to induce transcription of pro-inflammatory genes. Methods: PCR arrays and RT-PCR with individual primers were used to determine the effect of PGG on mRNA expression of genes involved in NFkB and MAPK signaling pathways. Western blots were performed to confirm PCR results. Results: The data obtained showed that PGG modulated the expression of 5 genes from the NFkB (BIRC3, CHUK, IRAK1, NFkB1, NOD1) and 2 genes from MAPK signaling pathway (CDK2 and MYC) when tested in RT-PCR assays. Western blots confirmed the PCR results at the protein level, showing that PGG attenuated the expression of total and phosphorylated proteins (CDK2, CHUK, IRAK1, and NFkB1) involved in NFkB and MAPK signaling. Conclusion: These findings show that PGG could modulate the expression of genes and proteins involved in the production of pro-inflammatory cytokines in microglia cells.