Anti-inflammatory effects of novel polygonum multiflorum compound via inhibiting NF-κB/MAPK and upregulating the Nrf2 pathways in LPS-stimulated microglia.

The incorporation of Polygonum multiflorum into the diet can result in anti-aging effects owing to its wide range of biological and pharmaceutical properties. We investigated the anti-neuroinflammatory properties of CRPE56IGIH isolated from P. multiflorum by focusing on its role in the induction of phase II antioxidant enzymes and the modulation of upstream signaling pathways. In microglia, CRPE56IGIH significantly inhibited lipopolysaccharide (LPS)-stimulated nitric oxide and prostaglandin E2 production with nonspecific cytotoxicity. CRPE56IGIH also markedly inhibited LPS-inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 protein and mRNA expression in the same manner as it inhibited nitric oxide and prostaglandin E2 production. In the control cells, NF-κB transactivation and nuclear translocation occurred at a baseline level, which was significantly increased in response to LPS. However, pretreatment with CRPE56IGIH concentration-dependently inhibited the LPS-induced NF-κB transactivation and nuclear translocation. The phosphorylation of Janus kinase-signal transducers and activators of transcription and mitogen-activated protein kinases was markedly upregulated by LPS, but considerably and dose-dependently inhibited by pretreatment with CRPE56IGIH. Furthermore, CRPE56IGIH induced the expression of phase II antioxidant enzymes, including heme oxygenase-1 (HO-1) and NADPH dehydrogenase quinone-1 (NQO-1). The activation of upstream signaling pathways, such as the Nrf2 pathway, was significantly increased following CRPE56IGIH treatment. Furthermore, the anti-neuroinflammatory effect of CRPE56IGIH was reversed by transfection of Nrf2, HO-1, and NQO-1 siRNA. Our results indicated that CRPE56IGIH isolated from P. multiflorum could be used as a natural anti-neuroinflammatory agent that induces phase II antioxidant enzymes via Nrf2 signaling.

Emodin induces neurite outgrowth through PI3K/Akt/GSK-3ß-mediated signaling pathways in Neuro2a cells.

In this study, a neurite outgrowth-inducing substance was isolated from the ethylacetate extract of the Polygonum multiflorum roots and identified as emodin by gas-liquid chromatography-mass spectrometry and (1)H NMR and (13)C NMR. Emodin displayed remarkable neurite outgrowth-inducing activity in Neuro2a cells, as demonstrated by morphological changes and immunocytochemistry for class III ß-tubulin. Emodin exhibited a stronger neutrophic activity than retinoic acid (RA) known as inducer of neurite outgrowth in Neuro2a cells. Emodin treatment resulted in marked increases in phosphorylation of Akt a direct downstream signaling molecule of phosphatidylinositol 3-kinase (PI3K), but upstream of glycogen synthase kinase-3ß (GSK-3ß) and cAMP response element-binding protein (CREB). These augmentations and neurite-bearing cells induced by emodin were remarkably reduced by the addition of PI3K inhibitor LY294002. These results demonstrate that emodin induces neuronal differentiation of Neuro2a cells via PI3K/Akt/GSK-3ß pathway.

Halofuginone induces the apoptosis of breast cancer cells and inhibits migration via downregulation of matrix metalloproteinase-9.

Halofuginone (HF) is extracted from Dichroa febrifuga, a plant used in traditional medicine. We report that the HF extract inhibits the growth of breast cancer cells and induces the generation of reactive oxygen species (ROS) and apoptosis, an important feature of potential anticancer agents. In addition, HF significantly reduces the migration and invasion of MCF-7 and MDA-MB-231 human breast cancer cells after 12-O-tetraecanoylphorbol-13-acetate (TPA) stimulation. As matrix metalloproteinase-9 plays a critical role in tumor metastasis, we analyzed its expression with the HF extract treatment. Western blot analysis and gelatin zymography showed that HF suppresses MMP-9 expression and activity concentration-dependently. HF also decreases the nuclear protein levels of nuclear factor kappa B (NF-κB) and c-fos (AP-1), critical transcription factors regulating MMP-9 expression through binding the MMP-9 promoter region. Luciferase assays showed that HF decreases TPA-induced MMP-9 promoter binding activities of NF-κB and AP-1. Taken together, these are the first results indicating that halofuginone may represent a promising new agent for breast cancer chemotherapy.

Acanthopanax senticosus exerts neuroprotective effects through HO-1 signaling in hippocampal and microglial cells.

Extracts of Acanthopanax senticosus, a traditional herb commonly found in Northeastern Asia, are used for treating neurodegenerative disorders such as ischemia and depression. However, the mechanisms of its neuroinflammatory and cytoprotective effects have not been investigated. We examined the mechanism of A. senticosus activity in anti-neuroinflammatory and neuroprotective processes. HO-1 is an inducible enzyme present in most cell lines. ASE increased HO-1 expression, which reduced LPS-induced nitric oxide/ROS production in BV2 cells. Moreover, the induction of HO-1 expression protected cells against glutamate-induced neuronal cell death. Activation of the p38-CREB pathway and translocation of Nrf2 are strongly involved in ASE-induced HO-1 expression. Our results showed that ASE-induced HO-1 expression through the p38-CREB pathway plays an important role in the generation of anti-neuroinflammatory and neuroprotective responses. ASE also increases the translocation of Nrf2 to regulate HO-1 expression. Furthermore, our results indicate that ASE serves as a potential therapeutic agent for neuronal disorders.

Bambusae Caulis in Taeniam modulates neuroprotective and anti-neuroinflammatory effects in hippocampal and microglial cells via HO-1- and Nrf-2-mediated pathways.

Recent evidence indicates that microglial activation and hippocampal damage may play important roles in neurodegenerative diseases, including Alzheimer's disease. Bambusae Caulis in Taeniam has been used as a folk remedy for the treatment of hypertension and cardiovascular disease in China and Korea. In this study, the mechanism responsible for the neuroprotective and anti-neuroinflammatory effects of Bambusae Caulis in Taeniam ethyl acetate fraction (BCE) was investigated. Heme oxygenase-1 (HO-1) is an inducible enzyme expressed in response to various inflammatory stimuli. Due to its role in the anti-inflammatory signaling pathway, the expression and modulation of HO-1 are important. In this study, the neuroprotective and anti-neuroinflammatory effects of BCE were examined using the murine microglial BV2 and hippocampal HT22 cells. We demonstrated that the administration of BCE provided neuroprotective effects against glutamate-induced cytotoxicity in HT22 cells through the HO-1 and nuclear erythroid-2 related factor 2 (Nrf-2) signaling pathways. We also reported that BCE inhibited lipopolysaccharide (LPS)-induced pro-inflammatory cytokines and that the presence of selective inhibitors of HO-1 (SnPP) resulted in the inhibition of BCE-mediated anti-inflammatory activity in BV2 microglial cells. BCE was shown to induce HO-1 expression as well as the nuclear translocation of Nrf-2 in both microglial and hippocampal cells. These findings revealed the potential therapeutic mechanisms of BCE in neurodegenerative diseases, suggesting that HO-1 and Nrf-2 signaling may play important roles in the mediation of its neuroprotective and anti-neuroinflammatory effects.

Anti-inflammatory effects of aromatic-turmerone through blocking of NF-κB, JNK, and p38 MAPK signaling pathways in amyloid ß-stimulated microglia.

Amyloid ß (Aß) induces the production of neuroinflammatory molecules, which may contribute to the pathogenesis of numerous neurodegenerative diseases. Therefore, suppression of neuroinflammatory molecules could be developed as a therapeutic method. Aromatic (ar)-turmerone, turmeric oil isolated from Curcuma longa, has long been used in Southeast Asia as both a remedy and a food. In this study, we investigated the anti-inflammatory effects of ar-turmerone in BV2 microglial cells. Aß-stimulated microglial cells were tested for the expression and activation of MMP-9, iNOS, and COX-2, the production of proinflammatory cytokines, chemokines, and ROS, as well as the underlying signaling pathways. Ar-turmerone significantly suppressed Aß-induced expression and activation of MMP-9, iNOS, and COX-2, but not MMP-2. Ar-turmerone also reduced TNF-α, IL-1ß, IL-6, and MCP-1 production in Aß-stimulated microglial cells. Further, ar-turmerone markedly inhibited the production of ROS. Impaired translocation and activation of NF-κB were observed in Aß-stimulated microglial cells exposed to ar-turmerone. Furthermore, ar-turmerone inhibited the phosphorylation and degradation of IκB-α as well as the phosphorylation of JNK and p38 MAPK. These results suggest that ar-turmerone impaired the Aß-induced inflammatory response of microglial cells by inhibiting the NF-κB, JNK, and p38 MAPK signaling pathways. Lastly, ar-turmerone protected hippocampal HT-22 cells from indirect neuronal toxicity induced by activated microglial cells. These novel findings provide new insights into the development of ar-turmerone as a therapeutic agent for the treatment of neurodegenerative disorders.

Suppression of α-MSH and IBMX-induced melanogenesis by cordycepin via inhibition of CREB and MITF, and activation of PI3K/Akt and ERK-dependent mechanisms.

Cordycepin has been a traditional medicine in China and Korea for centuries. This study explored the inhibitory effect of cordycepin on melanogenesis and the relative molecular mechanisms. Cordycepin inhibited melanin synthesis-related enzymes, such as tyrosinase, tyrosinase-related protein-1 (TRP1) and tyrosinase-related protein-2 (TRP2). α-MSH and IBMX were reported as melanin synthesis enhancers. Both of them could increase intracellular melanin synthesis by activation of the microphthalmia-associated transcription factor (MITF) signaling pathway. In the MITF pathway, the phosphorylation of cAMP related binding protein (CREB) activated the transcription of MITF, resulting in increasing melanin synthesis. Cordycepin also decreased the phosphorylation of CREB induced by α-MSH and IBMX in B16F10 melanoma cells. Accordingly, cordycepin inhibited melanogenesis signaling pathways by activating ERK and AKT signaling pathways to regulate the suppression of MITF and its downstream pathways including tyrosinase, TRP1 and TRP2. These results indicate the role of cordycepin as a potent depigmenting agent for cosmetics.