Synergistic Regulation of Microglia Gene Expression by Natural Molecules in Herbal Medicine

The activated microglia contribute to stroke-induced neuroinflammation by upregulating the expression of a pleura of genes that are characterized as either proinflammatory or anti-inflammatory. The natural products alantolactone (Ala) and dehydrodiisoeugenol (Deh) found in Inula helenium L. and Myristica fragrans Houtt., respectively, are regularly used in traditional herb medicine, which play anti-inflammatory and antioxidant roles via regulation of canonical pathways such as nuclear factor kappa B (NF-κB) in microglia and microphages. To illustrate the full spectra of gene expression alteration in microglia treated with Ala, Deh, and the mixture of Ala and Deh (denoted as Mix), we performed RNA-seq analysis of total RNA extracted from lipopolysaccharide- (LPS-) treated microglia subsequently exposed to Ala, Deh, and Mix. While both chemicals regulated the gene expression that facilitates an anti-inflammatory polarization, the mixture exerted some distinctive synergic regulatory effect, which differed from either of the chemicals alone. Our data provide important evidence for further research on the therapeutic mechanism of traditional medicine including Eerdun Wurile (EW).