Inhibitory effect of glycoprotein isolated from Cudrania tricuspidata bureau on expression of inflammation-related cytokine in bisphenol A-treated HMC-1 cells

Bisphenol A increases TLR4-mediated inflammatory response by up-regulation of autophagy-related protein in lung of adolescent mice

In previous studies we found that bisphenol A (BPA) aggravated OVA-induced lung inflammation. The aim of this research was to determine whether BPA exposure alone also induced inflammatory response in the lungs, which mechanism was associated with TLR4/NF-κB signaling pathway and the activation of mTOR-mediated autophagy. Female C57BL/6 mice aged 4 weeks were randomly divided into three groups (10/group): control group, 0.1 and 0.2 μg mL^-1 BPA groups. BPA induced the pathological changes in the lung and increased the levels of cytokines and inflammatory cells, as well as affected autophagy related proteins expression. In addition, the RAW264.7 cell culture experiment was conducted in order to confirm the role of autophagy. We found that BPA can enhance autophagy flux by enhancing autophagosome formation. It was further confirmed the details of the mechanism of action with chloroquine (CQ, a compound that inhibits the fusion of autophagosomes and lysosomes) intervention. The inhibition of autophagy led to down-regulation of expression levels associated with inflammation. This research results indicated that BPA induced inflammatory response in vitro and in vivo, and its mechanism may be related to TLR4/NF-κB signaling pathway and the activation of mTOR-mediated autophagy. After autophagy was suppressed, the inflammatory response also weakened. Our findings provide a new perspective into the mechanisms underlying inflammatory responses induced by the environmental exposure. These findings indicate that therapeutic strategies targeting autophagy may provide a new method for the treatment of inflammatory diseases.

Cudraflavanone B Isolated from the Root Bark of Cudrania tricuspidata Alleviates Lipopolysaccharide-Induced Inflammatory Responses by Downregulating NF-κB and ERK MAPK Signaling Pathways in RAW264.7 Macrophages and BV2 Microglia

A prenylated flavonoid, cudraflavanone B, is isolated from Cudrania tricuspidata. In this study, we investigated its anti-inflammatory and anti-neuroinflammatory effects in lipopolysaccharide (LPS)-induced RAW264.7 and BV2 cells. In our initial study of the anti-inflammatory effects of cudraflavanone B the production of nitric oxide and prostaglandin E2 was attenuated in LPS-stimulated RAW264.7 and BV2 cells. These inhibitory effects were related to the downregulation of inducible nitric oxide synthase and cyclooxygenase-2. In addition, cudraflavanone B suppressed the production of pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α in LPS-induced RAW264.7 and BV2 cells. Moreover, the evaluation of the molecular mechanisms underlying the anti-inflammatory effects of cudraflavanone B revealed that the compound attenuated the nuclear factor-kappa B signaling pathway in LPS-induced RAW264.7 and BV2 cells. In addition, cudraflavanone B inhibited the phosphorylation of extracellular signal-regulated kinase mitogen-activated protein kinase signaling pathways in these LPS-stimulated cells. Thus, cudraflavanone B suppressed nuclear factor-κB, and extracellular signal-regulated kinase mitogen-activated protein kinase mediated inflammatory pathways, demonstrating its potential in the treatment of neuroinflammatory conditions.

Females are more susceptible than male mice to thermal hypernociceptive behavior induced by early-life bisphenol-A exposure: Effectiveness of diphenyl diselenide

Humans are ubiquitously exposed to bisphenol A (BPA), one of the most used synthetic monomers for manufacturing polycarbonate plastics. BPA exposure leads to abnormal nociceptive perception and neuroinflammation in rodents. This study investigated whether diphenyl diselenide (PhSe)₂, a pleiotropic selenium-containing molecule, would be effective against the hypernociceptive behavior induced by the early-life BPA exposure to mice. Three-week-old male and female Swiss mice received intragastrically BPA (5 mg/kg) from 21^st to 60^th postnatal day. After, the mice received by the intragastric route (PhSe)₂ (1 mg/kg) once a day for seven days. After the last day of treatment, the mice performed the hot plate and tail immersion tests. The cerebral cortex samples were used to determine the levels of proteins related to apoptosis and inflammation. The results demonstrated that females were more susceptible than male mice to thermal hypernociception induced by early-life exposure to BPA. (PhSe)₂ was effective against the reduction in the latency to paw and tail withdrawal induced by BPA exposure in female mice. Furthermore, (PhSe)₂ restored the impairment in the levels of inflammatory proteins (COX-2, IL-1β, and p-JNK/JNK) but not those of apoptosis in the cerebral cortex of female mice exposed to BPA. Collectively, these data showed that females were more susceptible to thermal hypernociceptive behavior induced by early-life exposure to BPA than male mice. The administration of (PhSe)₂ reduced thermal hypernociceptive behavior, a sex independent effect, in BPA-exposed mice. (PhSe)₂ modulated inflammatory protein levels in the cerebral cortex of female mice exposed to BPA.

Steppogenin Isolated from Cudrania tricuspidata Shows Antineuroinflammatory Effects via NF-κB and MAPK Pathways in LPS-Stimulated BV2 and Primary Rat Microglial Cells

Excessive microglial stimulation has been recognized in several neurodegenerative diseases, including Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotropic lateral sclerosis (ALS), HIV-associated dementia (HAD), multiple sclerosis (MS), and stroke. When microglia are stimulated, they produce proinflammatory mediators and cytokines, including nitric oxide (NO) derived from inducible NO synthase (iNOS), prostaglandin E2 (PGE₂) derived from cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-12 (IL-12), and interleukin-6 (IL-6). These inflammatory reactions are related to the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Therefore, the modulation of NF-κB and MAPK is vital to prevent microglial activation and confer resistance against neuronal injury. In this study, steppogenin (1) isolated from Cudrania tricuspidata suppressed the neuroinflammatory responses to lipopolysaccharide (LPS). Steppogenin (1) inhibited the production of proinflammatory mediators and cytokines in LPS-challenged BV2 and rat primary microglial cells. Moreover, western blot analysis and immunofluorescence revealed that the nuclear translocation of NF-κB was inhibited in LPS-induced BV2 and rat primary microglial cells. The LPS-stimulated activation of BV2 and rat primary microglial cells was inhibited by steppogenin (1) through the suppression of c-Jun NH2-terminal kinase (JNK) and p38 MAPK signaling. These results suggested that steppogenin (1) exerted antineuroinflammatory effects against acute neuroinflammation in BV2 and rat primary microglial cells by suppressing the activation of NF-κB and MAPK signaling and the production of proinflammatory mediators and cytokines.

Cudrania tricuspidata: an updated review on ethnomedicine, phytochemistry and pharmacology

This review summarized the botany, traditional uses, phytochemistry and pharmacology ofCudrania tricuspidata, and the limitations of the studies on this species were also discussed so as to serve as the basis for further research and development of this medicinal plant.

Prenylated Xanthones from the Roots of Cudrania tricuspidata as Inhibitors of Lipopolysaccharide-Stimulated Nitric Oxide Production

Investigation of the CH₂ Cl₂ and EtOAc-soluble fractions of the roots of Cudrania tricuspidata afforded 31 compounds. The structures of the isolated compounds were determined on the basis of spectroscopic data interpretation such as 1D and 2D NMR analysis and elucidated as xanthones with prenyl moieties including four simple xanthones (1-4), five prenylated xanthones with one prenyl moiety (5-7, 20, and 21), and 22 prenylated xanthones with two prenyl moieties (8-19 and 22-31). Among them, three diprenylated xanthones named cudracuspixanthones E-G (16, 29, and 31) were first isolated in nature. Xanthones 2, 5, 6, 12, 19, 21, 22, 25, 27, and 28 showed moderate inhibition of lipopolysaccharide-stimulated nitric oxide production in RAW 264.7 cells, with IC₅₀ values ranging from 16.1 to 24.8 µM.

Bisphenol A at concentrations relevant to human exposure enhances histamine and cysteinyl leukotriene release from bone marrow-derived mast cells

Bisphenol A (BPA), a monomer of polycarbonate plastics and epoxide resin, acts as an endocrine-active compound and has been shown to enhance the inflammatory response to allergen challenge. Previous reports in rodents have demonstrated that perinatal BPA exposure alters airway inflammation following sensitization and challenge to ovalbumin in juvenile and adult offspring. Additionally, a high concentration of BPA has been shown to enhance mediator release in mast cell lines. This study aimed to determine if short-term BPA exposure, at levels relevant to human exposure, enhances mast cell release of histamine and cysteinyl leukotrienes (CysLTs). Primary murine bone marrow-derived mast cells (BMMC) produced from the femurs of female C57BL/6 mice were stimulated with BPA or estradiol (E2) in vitro. It was observed that both BPA and E2 increased BMMC histamine release over a range of nanomolar concentrations (1-1000 nM). The estrogen receptor (ER) antagonist ICI 182,780 partially blocked the ability of E2, but not BPA, to elevate histamine release. BPA also increased CysLT release, which was not abrogated by ER inhibition. It was also observed that the ability of BPA to enhance histamine and CysLT release was inhibited by blocking the extracellular signal-regulated kinase (ERK) pathway with U0126 or by chelating extracellular calcium (Ca(2+)) using EGTA. In summary, these experiments are the first to demonstrate that acute BPA exposure enhances mast cell histamine and CysLT release in vitro--an effect that is not dependent on an ER-mediated mechanism. Instead, BPA-induced mast cell histamine and CysLT release may be mediated, in part, by the ERK pathway and extracellular Ca(2+) concentrations. These data suggest that exposure to BPA at levels relevant to human exposure may provoke an acute inflammatory response in atopic individuals via enhanced mast cell activation.

Plant-originated glycoprotein (36 kDa) suppresses interleukin-4 and -10 in bisphenol A-stimulated primary cultured mouse lymphocytes

Bisphenol A (BPA) is one of the estrogen mimic environmental hormones and a chemical used for the wrapping foods, toy products for children, biomedical equipment, and machines. It can exert toxic effects, such as occurring allergy-related diseases. This study demonstrates that glycoprotein isolated from Rhus verniciflua Stokes (RVS glycoprotein) has an inhibitory activity of T-helper type 2 (Th2) cytokines [Interleukin (IL)-4 and -10]. First, it was shown that RVS glycoprotein inhibits the proliferation of lymphocytes and scavenges intracellular reactive oxygen species (ROS). Then, the activities of mitogen-activated protein kinase (MAPK), GATA-binding protein-3 (GATA-3), t-box expressed in T-cells (T-bet), and Th2 cell-related cytokine (IL-4 and -10) were evaluated in BPA (50 microM)-stimulated primary cultured mouse lymphocytes, using immunoblot analysis and reverse-transcription polymerase chain reaction (RT-PCR). The results showed that the RVS glycoprotein (50 microg/mL) inhibited the proliferation of lymphocytes, intracellular ROS, and activity of p38 MAPK dose dependently. In the transcriptional factors for the oriented differentiation of T-helper cells, the RVS glycoprotein (50 microg/mL) significantly suppressed the GATA-3, whereas it enhanced T-bet. Also, the RVS glycoprotein (100 microg/mL) significantly attenuated Th2-related cytokines (IL-4 and -10). Taken together, the results obtained from this study suggest that the RVS glycoprotein may help in preventing allergy-related immune dysfunction, such as that produced by BPA.

Expression of TNF-alpha and IL-6 in HMC-1 cells treated with bisphenol A is attenuated by plant-originating glycoprotein (75 kDa) by blocking p38 MAPK

Bisphenol A (BPA) is known as an estrogen-mimic environmental hormone which has the ability to indirectly stimulate the production of allergic inflammation-related cytokines. Cudrania tricuspidata Bureau (CTB) has been used in Korean folk medicine for a long time. In order to determine the inhibitory effect of a glycoprotein (CTB glycoprotein, 75 kDa) isolated from CTB fruits on the activities of allergic inflammation-related cytokines (TNF-alpha and IL-6) caused by BPA, we evaluated the activities of protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor (NF)-kappaB, and inflammation-related cytokine (TNF-alpha and IL-6) in the BPA-induced HMC-1 cells using immunoblot analysis and RT-PCR. The results obtained from this study revealed that CTB glycoprotein (100 microg/ml) inhibits the translocation of PKC from cytosol to the membrane, the phosphorylation of p38 MAPK, the activation of NF-kappaB, and the expression levels of TNF-alpha and IL-6. Taken together, the results in this study suggest that CTB glycoprotein inhibits the expression of allergic inflammation-related cytokines (TNF-alpha and IL-6) by blocking NF-kappaB and p38 kinase in BPA-induced HMC-1 cells.