Coelonin protects against PM2 .5 -induced macrophage damage via suppressing TLR4/NF-κB/COX-2 signaling pathway and NLRP3 inflammasome activation in vitro.

One of the important monitoring indicators of the air pollution is atmospheric fine particulate matter (PM2.5 ), which can induce lung inflammation after inhalation. Coelonin can alleviate PM2.5 -induced macrophage damage through anti-inflammation. However, its molecular mechanism remains unclear. We hypothesized that macrophage damage may involve the release of inflammatory cytokines, activation of inflammatory pathways, and pyrosis induced by inflammasome. In this study, we evaluated the anti-inflammation activity of coelonin in PM2.5 -induced macrophage and its mechanism of action. Nitric oxide (NO) and reactive oxygen species (ROS) production were measured by NO Assay kit and dichlorofluorescein-diacetate (DCFH-DA), and apoptosis were measured by Flow cytometry and TUNEL staining. The concentration of inflammatory cytokines production was measured with cytometric bead arrays and ELISA kits. The activation of NF-κB signaling pathway and NLRP3 inflammasome were measured by immunofluorescence, quantitative reverse transcription-polymerase chain reaction and western blot. As expected, coelonin pretreatment reduced NO production significantly as well as alleviated cell damage by decreasing ROS and apoptosis. It decreased generation of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in PM2.5 -induced RAW264.7 and J774A.1 cells. Moreover, coelonin markedly inhibited upregulating the expression of toll-like receptor (TLR)4 and cyclo-oxygenase (COX)-2, blocked activation of p-nuclear factor-kappa B (NF-κB) signaling pathway, and suppressed expression of NLRP3 inflammasome, ASC, GSDMD, IL-18 and IL-1ß. In conclusion, the results showed that coelonin could protect against PM2.5 -induced macrophage damage via suppressing TLR4/NF-κB/COX-2 signaling pathway and NLRP3 inflammasome activation in vitro.

Polysaccharides from Tetrastigma hemsleyanum Diels et Gilg: optimum extraction, monosaccharide compositions, and antioxidant activity.

The optimization of extraction of Tetrastigma hemsleyanum Diels et Gilg polysaccharides (THP) using ultrasonic with enzyme method and its monosaccharide compositions and antioxidant activity were investigated in this work. Single-factor experiments and response surface methodology (RSM) were performed to optimize conditions for extraction, and the independent variables were (XA) dosage of cellulase, (XB) extraction time, (XC) ultrasonic power, and (XD) ratio of water to the material. The extraction rate of THP was increased effectively under the optimum conditions, and the maximum (4.692 ± 0.059%) was well-matched the predicted value from RSM. THP was consisted of mannose, glucuronic acid, rhamnose, galacturonic acid, glucose, galactose, and arabinose, while glucose was the dominant (26.749 ± 0.634%). According to the total antioxidant capacity assay with the FRAP method, DPPH, and hydroxyl radical scavenging assay, THP showed strong antioxidant activity with a dose-dependent behavior. The results indicated that THP has the potential to be a novel antioxidant and could expand its application in food and medicine.

Protective effects of flavonoids from the leaves of Carya cathayensis Sarg. against H2O2-induced oxidative damage and apoptosis in vitro.

Hydrogen peroxide (H2O2) can induce apoptosis by releasing reactive oxygen species (ROS) and reactive nitrogen species, which cause mitochondrial damage. The present study aimed to investigate the protective effects of flavonoids from the leaves of Carya cathayensis Sarg. against H2O2-induced oxidative damage and apoptosis in vitro. The bioactivity of total flavonoids (TFs) and five monomeric flavonoids [cardamonin (Car), pinostrobin chalcone, wogonin, chrysin and pinocembrin] from the leaves of Carya cathayensis Sarg. (LCCS) were tested to prevent oxidative damage to rat aortic endothelial cells (RAECs) induced by H2O2. Oxidated superoxide dismutase, glutathione peroxidase, malondialdehyde, lactate dehydrogenase and ROS were analyzed to evaluate the antioxidant activity. Gene and protein expression patterns were assessed using reverse transcription-quantitative PCR and western blotting, respectively. The results indicated that TFs and Car inhibited H2O2-induced cytotoxicity and apoptosis of RAECs. Additionally, they regulated the level of oxidase and inhibited the production of ROS. Overall, the TFs extracted from LCCS could potentially be developed as effective candidate drugs to prevent oxidative stress in the future; moreover, they could also provide a direction in investigations for preventing antioxidant activity through the ROS pathway.

Polysaccharide Isolated From Tetrastigma hemsleyanum Activates TLR4 in Macrophage Cell Lines and Enhances Immune Responses in OVA-Immunized and LLC-Bearing Mouse Models.

Tetrastigma hemsleyanum Diels et Gilg is a valuable Chinese medicinal herb with a long history of clinical application. Our previous study isolated and characterized a purified polysaccharide from the aerial part of Tetrastigma hemsleyanum (SYQP) and found it having antipyretic and antitumor effects in mice. A preliminary mechanistic study suggests these effects may be related to the binding of toll-like receptor (TLR4). The objective of this study is to further explore the detailed stimulating characteristics of SYQP on TLR4 signaling pathway and its in vivo immune regulating effect. We use HEK-BLUE hTLR4, mouse and human macrophage cell lines, as research tools. In vitro results show SYQP activated HEK-BLUE hTLR4 instead of HEK-BLUE Null cells. The secretion and the mRNA expression of cytokines related to TLR4 signaling significantly increased after SYQP treatment in both PMA-induced THP-1 and RAW264.7 macrophage cell lines. The TLR4 antagonist TAK-242 can almost completely abolish this activation. Furthermore, molecules such as IRAK1, NF-κB, MAPKs, and IRF3 in both the MyD88 and TRIF branches were all activated without pathway selection. In vivo results show SYQP enhanced antigen-specific spleen lymphocyte proliferation and serum IgG levels in OVA-immunized C57BL/6 mice. Orally administered 200 mg/kg SYQP induced obvious tumor regression, spleen weight increase, and the upregulation of the mRNA expression of TLR4-related cytokines in Lewis lung carcinoma-bearing mice. These results indicate SYQP can act as both a human and mouse TLR4 agonist and enhance immune responses in mice (p < 0.05). This study provides a basis for the development and utilization of SYQP as a new type of TLR4 agonist in the future.

Role of Militarine in PM2.5-Induced BV-2 Cell Damage.

A growing number of studies have shown that air fine particulate matter (PM2.5) pollution is closely associated with neuroinflammation in humans. Militarine, a glucosyloxybenzyl 2-isobutylmalate compound isolated from Bletilla striata, has been found to exert significant neuroprotective effects. However, the anti-inflammatory, antioxidant and antiapoptotic effects of militarine on PM2.5-stimulated BV-2 microglial cells have not been reported. This study aimed to investigate the protective effects of militarine against PM2.5-induced cytotoxicity and its mechanism in BV-2 microglial cells. Our results revealed that pretreatment with 0.31-1.25 µg/mL militarine reversed the morphological changes caused by PM2.5 and decreased proinflammatory cytokine generation and gene expression in PM2.5-treated BV-2 cells. In particular, tumor necrosis factor-α and interleukin-6 expression was inhibited in a dose-dependent manner. Notably, militarine markedly inhibited the upregulation of Toll-like receptor 4, Toll-like receptor 2, and cyclo-oxygenase-2 expression at both the mRNA and protein levels and reduced NF-κB pathway-associated protein expression. Immunofluorescence analysis showed that militarine suppressed NF-κB activity through inhibiting p65 nuclear translocation. Our data suggested that militarine alleviated neuroinflammation in BV-2 microglial cells, possibly by inhibiting the expression of neuroinflammatory cytokines through the TLR/NF-κB signaling pathway. Additionally, militarine significantly reduced PM2.5-mediated reactive oxygen species (ROS) generation and cell apoptosis and restored the mitochondrial membrane potential (MMP; ΔΨm). Collectively, these findings demonstrate that militarine played a protective role against PM2.5-induced damage in BV-2 cells by exerting anti-inflammatory, antioxidant, and antiapoptotic effects.

Molecular docking simulation and in vitro studies on estrogenic activities of flavonoids from leaves of Carya cathayensis Sarg.

The main purpose of this study was to evaluate the estrogenic properties of total flavonoids (TFs) and five flavonoid monomers (cardamonin (Car), pinostrobin chalcone (PC), wogonin (Wo), chrysin (Chr) and Pinocembrin (PI)) from leaves of Carya cathayensis Sarg (LCC). TFs from LCC were isolated and determined using HPLC. The 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were performed to assess the effects of flavonoids on cell proliferation and cell cycle, respectively. The molecular docking technique was applied to investigate binding conformations of the monomers from LCC to the estrogen receptor ERα and ERß. Gene and protein expression patterns were assessed using quantitative real-time PCR (qRT-PCR) and western blot, respectively. The results showed that TFs, Car, PC, Wo and Chr promoted proliferation of MCF-7 cells and cell transition from the G1 to S phase, and inhabitation of MCF-7 cell proliferation was observed after the treatment of PI. Molecular docking studies confirmed ERs as molecular targets for the monomers. TFs, Car, PC, Wo and Chr from LCC promoted gene expression of ERα, ERß, progesterone receptor (PR) and pS2. Our collective results demonstrated that TFs and monomers from LCC may exert ER agonist activity through competitively bind to ER, inducing ER upregulation and active ER to estrogen response element (ERE)- independent gene regulation. As an abundant natural product, LCC may provide a novel medicinal source for treatment of diseases caused by estrogen deficiency.

[Chrysin inhibits adipogenic differentiation of mouse embryonic fibroblasts].

Chrysin is an active flavonoid wildly presented in many herbs. It has the effect to reduce serum lipid. To investigate the effect of chrysin on the adipogenic differentiation of mouse embryonic fibroblasts, methyl thiazolyl tetrazolium (MTT) and crystal violet were used to detect the cytotoxic effect of chrysin on Immortalized mouse embryonic fibroblasts (iMEFs). Propidium iodide (PI) staining combined with flow cytometry (FCM) was employed to detect the effects of different concentrations of chrysin on iMEFs cell cycle. The effect of chrysin on adipogenic differentiation ability of iMEFs was determined by oil red O staining. Semi-quantitative PCR was employed to detect the effect of chrysin on mRNA transcriptional levels of adipogenic differentiation markers, including perilipin 2, adiponectin (adipoq), Fabp4, LPL, MCP-1 and adipogenic differentiation key transcription factor peroxisome proliferators-actiated receptor-gamma 2(PPAR-γ2). Results indicated that chrysin had certain cytotoxic effect for iMEFs in a dose-dependent manner, and the IC50 was identified nearly to 30 µmol•L⁻¹. FCM analysis showed that chrysin could affect the cell-cycle distribution of iMEFs, increasing the ratio of cells in G1 phase. Adipogenic differentiation inducing experiment showed that 30 µmol•L⁻¹ chrysin significantly reduced lipid drops accumulation induced by insulin and dexamethasone. In addition, the mRNA transcriptional levels of PPAR-γ2 and LPL were significantly decreased and mRNA levels of fabp 4, MCP-1, adipoq were also affected after chrysin treatment. The experiment results suggest that chrysin attenuates the adipogenic differentiation capacity of mesenchymal stem cells.