Paeonol Suppresses Neuroinflammatory Responses in LPS-Activated Microglia Cells.

In this work, we assessed the anti-inflammatory effects of paeonol (PAE) in LPS-activated N9 microglia cells, as well as its underlying molecular mechanisms. PAE had no adverse effect on the viability of murine microglia N9 cell line within a broad range (0.12∼75 µM). When N9 cell line was activated by LPS, PAE (0.6, 3, 15 µM) significantly suppressed the release of proinflammatory products, such as nitric oxide (NO), interleukin-1ß (IL-1ß), and prostaglandin E2 (PGE2), demonstrated by the ELISA assay. Moreover, the levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) were significantly reduced in PAE-treated N9 microglia cells. We also examined some proteins involved in immune signaling pathways and found that PAE treatment significantly decreased the expression of TLR4, MyD88, IRAK4, TNFR-associated factor 6 (TRAF6), p-IkB-α, and NF-kB p65, as well as the mitogen-activated protein kinase (MAPK) pathway molecules p-P38, p-JNK, and p-ERK, indicating that PAE might act on these signaling pathways to inhibit inflammatory responses. Overall, we found that PAE had anti-inflammatory effect on LPS-activated N9 microglia cells, possibly via inhibiting the TLR4 signaling pathway, and it could be a potential drug therapy for inflammation-associated neurodegenerative diseases.

[Inhibitory effect of ferulic acid on inflammatory response in microglia induced by lipopolysaccharides].

Ferulic acid (FA) is a natural compound that expresses antioxidant and anti-inflammatory activities. Microglial cells are innate immune cells that reside within the central nervous system (CNS). Activated microglia mediated neuronal immunity contributes to the neurodegeneration associated with Alzheimer's disease. In this study, we investigated the inhibitory effect of FA on neuroinflammation in BV-2 microglial cells induced by lipopolysaccharides (LPS). Our study showed that FA significantly suppressed the production of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-1ß (IL-1ß), and decreased induced type II nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein in LPS-stimulated BV-2 microglia cells in a dose dependent manner. We hypothesized that this was achieved by suppressing the protein level of Toll-like receptor 4 (TLR4).

[The inhibitory effect of luteolin on inflammation in LPS-induced microglia].

OBJECTIVE: To study the inhibitory effect of Luteolin on LPS-induced BV-2 cell. METHODS: BV-2 cells were treated with LPS (0.1 microg/mL) for inflammation model; MTT assay was used to detect the viability of BV-2 cells; Nitric oxide (NO) was detected by the method of nitric acid reductase assay; Induce type II nitric oxide synthase (iNOS) enzyme activity was determined by type of nitric oxide synthase assay;TLR4 protein expression was examined by the Western Blot analysis. RESULTS: Luteolin significantly decreased the NO production and TLR4 protein expression as well as iNOS activity in LPS-activated microglial cell. CONCLUSION: LPS induced activation of microglia lead to inflammatory response and its mechanism may be related to inhibiting TLR4 signaling pathway.

[Primary study on mechanism of baicalin on the Th1/Th2 response in murine model of asthma].

OBJECTIVE: To study the mechanism of baicalin on the cytokines of Th1/Th2 in murine model of asthma. METHODS: The murine model of asthma was induced by OVA. Different doses of baicalin were orally administered to the mice respectively. The spleen cells were cultured 3 days for the measurement of IFN-gamma, IL-4, IL-5 and IL-10 by ELISA. After 2 days of culture, the spleen cells were treated with Trizol for extraction of total RNA. The gene expressions of T-bet, GATA-3 and STAT-6 were analyzed by RT-PCR. RESULTS: The treatment with baicalin obviously decreased the production of IL-4 and IL-5 and the gene expression of GATA-3, STAT-6, but increased the production of IL-10. CONCLUSION: Baicalin may modulate the Th1/Th2 balance mainly by altering the gene expressions of GATA-3 and STAT-6 in vivo and increasing the production of IL-10.

Inhibition of the antigen-induced activation of RBL-2H3 cells by Gab2 siRNA.

Gab2 plays an important role in FcepsilonRI mediated signal events which lead to degranulation from mast cells. The present study was designed to investigate the effect of the synthetic Gab2 (scaffolding adapter Grb2-associated binder 2) siRNA on the antigen-induced activation of RBL-2H3 cells. A double stranded siRNA against Gab2-mRNA was synthesized and transfected into RBL-2H3 cells. After 6 h, cells were then sensitized with dinitrophenyl (DNP)-specific IgE overnight and challenged with dinitrophenyl-human serum albumin (DNP-HSA) to induce mast cell degranulation before supernatants were collected. Effects of Gab2 siRNA on antigen-induced release of beta-hexosaminidase and histamine, cytokine production and regulation of the proteins in the pathway were measured by enzymatic assay, EIA, ELISA and Western blotting. Treatment with Gab2 siRNA significantly decreased Gab2 expression, inhibited the FcepsilonRI-mediated mast cell release of beta-hexosaminidase and histamine, reduced the production of IL-4 and TNF-alpha and inhibited the phosphorylation of Akt, PKCdelta and p38 mitogen-activated protein kinase (MAPK). Data showed that Gab2 siRNA could suppress the antigen-induced activation of RBL-2H3 cells and suggested a possible mechanism through inhibition of signaling molecules downstream of Gab2 in the FcepsilonRI-mediated Ca(2+)-independent pathway. Furthermore, potential usefulness of Gab2 knock-down as a method for inhibition of mast cell-mediated allergic reactions was demonstrated.