Nurr1: A vital participant in the TLR4-NF-κB signal pathway stimulated by α-synuclein in BV-2 cells.

Parkinson's disease (PD) is a multi-factorial neurodegenerative disease. Abnormal α-synuclein protein aggregate and sustained microglia activation contribute to the pathogenic processes of PD. However, the relationship between α-synuclein and microglia-mediated neuroinflammation remains unclear. We purified α-synuclein after overexpression in Escherichia coli and then used it to stimulate BV-2 cells or primary microglia cells from wild type or toll-like receptor 4 (TLR4)-defective mice. Enzyme linked immunosorbent assay (ELISA) and real-time PCR results confirmed that α-synuclein could enhance the production of tumor necrosis factor α (TNF-α) through TLR4 activation. Western blotting results confirmed the involvement of the TLR4/PI3K/AKT/GSK3ß signal pathway in the inflammatory response. Nuclear factor kappa B (NF-κB) could translocate to the nucleus, promoting the expression of TNF-α when stimulated by α-synuclein in BV-2 cells. Nurr1 suppressed the production of TNF-α via interaction with NF-κB/p65 and inhibiting its nuclear translocation. In addition, both NF-κB and Nurr1 appeared to be regulated by the TLR4-mediated signal pathway. Our work demonstrated that TLR4 recognized α-synuclein and activated downstream signaling mechanisms leading to the release of pro-inflammatory mediators that are contra-balanced by Nurr1 expression. In conclusion, Nurr1 is a novel participant in the neuroinflammation stimulated by α-synuclein, thus the regulation of Nurr1 may be a novel neuroprotective target for PD treatment.

The inhibition effect and mechanism of SY0916 on pulmonary fibrosis.

SY0916 is a new platelet-activating factor receptor antagonist developed by our institute. In this study, the inhibitory effect of SY0916 on pulmonary fibrosis was investigated in epithelial-mesenchymal transition (EMT) induced by transforming growth factor beta 1 (TGF-ß1) in vitro and a pulmonary fibrosis animal model induced by bleomycin (BLM). The results showed that SY0916 could inhibit the EMT of A549 cells induced with TGF-ß1. In vivo, SY0916 administration significantly ameliorated the BLM-mediated histological changes, reduced main biochemical parameters related to pulmonary fibrosis such as hydroxyproline and glutathione, and also notably attenuated the expression of key pro-fibrotic mediator, TGF-ß1. These findings demonstrated that SY0916 could possibly be developed as a promising candidate for the treatment of pulmonary fibrosis.

Rotenone could activate microglia through NFκB associated pathway.

Parkinson's disease (PD) is a common neurodegenerative disease, and its etiology remains obscure. Increasing evidence has suggested an important role for environmental factors such as exposure to pesticides in increasing the risk of developing PD and inflammation is the early incident during the process of PD. In this study, we measure the pro-inflammatory cytokines by enzyme-linked immunosorbnent assay and RT-PCR methods; analyze the reactive oxygen species by DCFH-DA; detected nuclear factor κB (NFκB) translocation by western blot and immunofluorescence methods; and analyze the phosphorylation of mitogen-activated protein (MAP) kinase and protein level of Nurr1 by western blot. Results showed that rotenone could induce tumor neurosis factor α (TNFα) and interleukin 1ß (IL-1ß) release from BV-2 cells, enhance TNFα and IL-1ß mRNA levels in substantia nigra lesioned by rotenone; also, rotenone could increase the phosphorylation of inhibitor of κB (IκB), extracellular regulated protein kinase , c-Jun N-terminal kinase, p38 MAP kinases and promote p65 subunit of NFκB translocation to nuclear; at the same time, rotenone could decrease the protein level of Nurr1 in nuclear. So, rotenone exerted toxicity through activating microglia, and its mechanism might be associated with NFκB signal pathway.

Inhibitory effects of SY0916, a platelet-activating factor receptor antagonist, on the angiogenesis of human umbilical vascular endothelial cells.

SY0916 is a novel platelet-activating factor receptor antagonist. The objective of this study is to explore the anti-angiogenesis effects of SY0916 on human umbilical vascular endothelial cell (HUVEC) and to understand its possible mechanism. The effect of SY0916 on proliferation of HUVEC was measured by the MTT method, whereas the effect of SY0916 on HUVEC chemotaxis was carried out by Boyden chamber assay. The activities of metalloproteinase (MMP)-9 and MMP-2 were detected using gelatin zymography, and the expression of intercellular adhesion molecules-1 (ICAM-1) was measured by Western blot analysis. The 2D tube formation experiment of HUVEC with 10% fetal calf serum on Matrigel was also evaluated. It was shown that SY0916 had significant inhibitory effects on the proliferation and the chemotaxis of HUVEC induced by phorbol-12-myristate-13-acetate in a positive dose-dependent manner. Furthermore, SY0916 could significantly suppress the activity of MMP-2 and MMP-9 and decrease the expression of ICAM-1 in HUVEC. In 2D tube formation test, SY0916 could effectively inhibit the formation of vascular structure on Matrigel. The results showed that SY0916 could block the chemotaxis of HUVEC, and then inhibit the tube formation on Matrigel. Such anti-angiogenesis effect of SY0916 on HUVEC might relate to downregulate the expressions of MMP-2, MMP-9, and ICAM-1.

Inhibition of 5-lipoxygenase and cyclooxygenase-2 pathways by pain-relieving plaster in macrophages.

CONTEXT: Pain-relieving plaster (PRP) is a traditional Chinese medicine (TCM) that has been widely used with satisfactory results in the treatment of some diseases related to inflammation, such as bruises, chronic arthritis. OBJECTIVE: The mechanisms underlying the anti-inflammatory actions of PRP are investigated in this study for the first time. MATERIALS AND METHODS: The anti-inflammatory effects of PRP extracts were evaluated in lipopolysaccharide (LPS) or calcium ionophore A23187-treated murine peritoneal macrophages (PMs). Tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), prostaglandin E2 (PGE2), and leukotrienes B4 (LTB4) were evaluated by ELISA assays. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). Nuclear factor-kappa B (NF-κB)-DNA-binding activity was determined by gel mobility shift assay. RESULTS: PRP extracts were found to inhibit the production of TNF-α, IL-1ß, and PGE(2), reduce the expressions of COX-2 at the mRNA and protein levels induced by LPS, and reduced the production of LTB4 induced by A23187. Furthermore, PRP extracts significantly attenuated LPS-induced NF-κB-DNA-binding activity. DISCUSSION AND CONCLUSION: The anti-inflammatory effects of PRP possibly are related to reduction of inflammatory cytokines (TNF-α and IL-1ß), inducible inflammatory enzyme (COX-2), and its metabolite PGE2 via NF-κB signal pathway. Moreover, PRP extracts also notably inhibited the production of LTB4, indicating that PRP inhibited the 5-LOX pathway, which may be the other mechanism for its anti-inflammatory action.

Effects and mechanism of aromatic aminoketone SY0916 on osteoclastic bone destruction.

AIM: To study the effects and mechanism of aromatic aminoketone (SY0916) on bone destruction in vitro. METHODS: MC3T3-E1 cells and bone marrow cells were co-cultured to obtain purified osteoclasts. The proliferation of osteoclast-like cells (OCLs) was determined by MTT assay. The number of osteoclasts was measured by tartrate-resistant acid phosphatase (TRAP) staining. The functioning of osteoclasts was determined by measuring the area of bone resorption pits on bone slices. MMP-9 secretion by osteoclasts was measured by an ELISA kit. Osteoclast apoptosis was detected by flow cytometry using an AnnexinV-FITC kit. Gene expression of RANK and MMP-9 in osteoclasts as well as RANKL and OPG in MC3T3-E1 cells was determined by real-time PCR. RESULTS: SY0916 significantly inhibited the proliferation of OCLs, decreased both the total and average area of bone resorption pits, and dramatically inhibited the number of osteoclasts between concentrations of 0.01 and 10 micromol/L. Furthermore, SY0916 reversed IL-1 beta-mediated inhibition of osteoclast apoptosis and shortened osteoclast lifespan. In addition, SY0916 significantly inhibited the mRNA expression of RANK, RANKL, OPG, and MMP-9. However, the inhibition of OPG was weaker than that of RANKL. Accordingly, the ratio of RANKL to OPG mRNA expression in MC3T3-E1 cells was significantly decreased by SY0916. Meanwhile, the expression of MMP-9 protein in osteoclasts was inhibited by SY0916 between 0.01 and 10 micromol/L. CONCLUSION: SY0916 prevents osteoclastic bone destruction by inhibiting the proliferation and function of osteoclasts. The underlying mechanism for this effect involves the regulation of the RANKL-OPG-RANK axis, which determines the direction of bone metabolism.

[Effect of ginkgolide B on the production of NO, IL-6 and RANTES from astrocytes].

This study is to explore the effect of ginkgolide B (BN52021) on the production of nitric oxide (NO), interleukin (IL)-6 and regulated upon activation normal T cell expressed and secreted (RANTES) from astrocytes induced by stimulators. Primary cultured rat astrocytes were stimulated with lipopolysaccharides (LPS), the production of NO was assayed using Griess reaction; U251 cells were stimulated with IL-1 beta, the contents of IL-6 and RANTES in the supernatant were measured using ELISA. The mRNA expressions of IL-6 and RANTES were detected using RT-PCR. LPS (10 ng mL(-1) to 10 microg mL(-1)) could stimulate rat astrocytes to produce NO in a dose-dependent manner. Ginkgolide B at the concentrations of 0.1-10 micromol L(-1) were shown to decrease NO production significantly. IL-1 beta could induce the mRNA expression and protein secretion of IL-6 from U251 cells, as well as RANTES. Ginkgolide B at concentrations of 0.1-10 micromol L(-1) were shown to inhibit RANTES secretion, and to inhibit mRNA expression of IL-6 and RANTES at concentration of 10 micromol L(-1). Ginkgolide B has inhibitory effect on the production of NO, IL-6 and RANTES from astrocytes treated with inflammatory stimulators.

[Effects of extracts of cheezheng pain relieving plaster on nitric oxide and iNOS expression in macrophages induced by lipopolysaccharides].

This study is to explore the effects of extracts of Cheezheng pain relieving plaster (ECPRP) on nitric oxide (NO) production and expression of inducible nitric oxide synthase (iNOS) in macrophages induced by LPS and the mechanism involved. Nitric oxide level was measured with Griess reagent assay. Inducible nitric oxide synthase (iNOS) protein and NF-kappaBp65 fragment were detected with Western blotting. ECPRP (62.5 and 125 mgL(-1)) significantly inhibited the increase of nitric oxide level. Furthermore, ECPRP (62.5 and 125 mg x L(-1)) notably reduced the expression of iNOS mRNA and protein. ECPRP (62.5 and 125 mg x L(-1)) elevated the content of I-kappaB protein in cytoplasm, while decreased the content of NF-kappaBp65 protein in nucleus. These results suggest that ECPRP reduce nitric oxide level via down-regulation of NF-kappaB-iNOS-nitric oxide pathway, resulting in prevention of inflammation.

Effect of ginkgolide B on the platelet-activating factor induced changes of chemotaxis and cytoskeleton of macrophages.

AIM: To study the inhibitory effect of ginkgolide B (BN52021) on the PAF induced changes of chemotaxis of murine peritoneal macrophages and the related polymerization of F-actin. METHODS: Chemotaxis assays were performed using a modified 48-well Boyden chamber. Actin polymerization of murine peritoneal macrophages was analyzed by flow cytometry using a specific fluorescent stain. RESULTS: Peritoneal macrophages significantly migrated toward platelet-activating factor (PAF) through a micropore filter; however, in the presence of PAF receptor antagonist BN52021 (0.01 nmol x L(-1) -0.1 micromol x L(-1)), the migration was significantly inhibited. Moreover, BN52021 inhibited the actin polymerization of murine peritoneal macrophages induced by PAF in the presence of Ca2+, but not in Ca2+ -free medium. CONCLUSION: The results suggested that preventing polymerization of F-actin may be a pathway by BN52021 to inhibit the chemotaxis of macrophages, and this effect seems to be Ca2+ dependent. The data further indicated that inhibition of PAF induced macrophage chemotaxis is an important mechanism underlying the anti-inflammatory action of BN52021.

[Effects of ginkgolide B on lipopolysaccharide-induced TNFalpha production in mouse peritoneal macrophages and NF-kappaB activation in rat pleural polymorphonuclear leukocytes].

AIM: To study the effects of ginkgolide B on lipopolysaccharide (LPS)--induced TNFalpha production in mouse peritoneal macrophages and NF-kappaB activation in rat pleural polymorphonuclear leukocytes. METHODS: L929 crystal violet staining assay was used to show the level of TNFalpha released from mouse peritoneal macrophages induced by LPS. Electrophoretic mobility shift assay (EMSA) was used to determine NF-kappaB binding activities. RESULTS: Ginkgolide B (1, 10 micromol x L(-1)) was shown to significantly inhibit LPS (10 mg x L(-1))-induced TNFalpha production in mouse peritoneal macrophages, the IC50 was 0.26 micromol x L(-1); LPS (1 mg x L(-1)) and PAF (1 nmol , L(-1)) were shown to increase the NF-kappaB binding activities in rat pleural polymorphonuclear leukocytes; ginkgolide B (10 micromol x L(-1)) was found to inhibit LPS (1 mg x L(-1))-induced NF-kappaB activation in rat pleural polymorphonuclear leukocytes; ginkgolide B (1, 10 micromol x L(-1)) was shown to inhibit PAF (1 nmol x L(-1))-induced NF-kappaB activation in rat pleural polymorphonuclear leukocytes. CONCLUSION: The inhibition of NF-kappaB activation and TNFalpha production might be considered to be part of the mechanisms underlying the antiinflammatory action of ginkgolide B; PAF is involved in activation of the NF-kappaB pathway stimulated with LPS.