Linalool attenuates lung inflammation induced by Pasteurella multocida via activating Nrf-2 signaling pathway.

Pasteurellosis caused by Pasteurella multocida manifest often as respiratory infection in farmed small ruminants. Although the incidence of pasteurellosis due to P. multocida mainly takes the form of pneumonia, there is limited information on host factors that play a role in disease pathogenesis in the milieu of host-pathogen interactions. Nuclear factor-erythroid 2 related factor 2 (Nrf-2), a critical regulator for various inflammatory and immune responses by controlling oxidative stress, may play an important role in the processes of inflammation induced by P. multocida. In this study, linalool, a natural compound of the essential oils in several aromatic plant species, elevated nuclear Nrf-2 protein translocation in the A549 lung cell line and in vivo. The P. multocida-induced pro-inflammatory cytokines expression was abrogated by Nrf-2 siRNA. Postponed treatment with linalool decreased lung neutrophil accumulation and enhanced clearance of P. multocida. Furthermore, linalool significantly increased the expression of antioxidant enzymes regulated by Nrf-2 and diminished lung tissue levels of several pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) and interleukin (IL)-6. In addition, animals treated with linalool had a marked improvement in survival. These findings have uncovered that linalool acts as a novel Nrf-2 activator for a novel therapeutic strategy in pathogen-mediated lung inflammation.

p-Synephrine suppresses lipopolysaccharide-induced acute lung injury by inhibition of the NF-κB signaling pathway.

OBJECTIVE: We investigated whether p-synephrine exerts potent anti-inflammatory effects against acute lung injury (ALI) induced by lipopolysaccharide (LPS) in vivo, and we further investigated the inhibitory mechanism of p-synephrine in LPS-induced ALI. METHODS: Lipopolysaccharide (0.5 mg/kg) was instilled intranasally in phosphate-buffered saline to induce acute lung injury, and 6, 24, and 48 h after LPS was given, bronchoalveolar lavage fluid was obtained to measure pro-inflammatory mediator. We also evaluated the effects of p-synephrine on LPS-induced the severity of pulmonary injury. The phosphorylation of nuclear factor-κB (NF-κB) p65 protein was analyzed by Western blotting. RESULTS: Our data showed that p-synephrine significantly reduced the amount of inflammatory cells, the lung wet-to-dry weight (W/D) ratio, reactive oxygen species, myeloperoxidase activity and enhanced superoxide dismutase (SOD) in mice with LPS-induced ALI. Tumor necrosis factor α and interleukin (IL)-6 concentrations decreased significantly while the concentration of IL-10 was significantly increased after p-synephrine pretreatment. In addition, p-synephrine suppressed not only the phosphorylation of NF-κB but also the degradation of its inhibitor (IκBα). CONCLUSIONS: These results suggested that the inhibition of NF-κB activation and the regulation of SOD are involved in the mechanism of p-synephrine's protection against ALI.

Zingerone attenuates lipopolysaccharide-induced acute lung injury in mice.

Zingerone, one of the active components of ginger, is a phenolic alkanone with antioxidant and anti-inflammatory properties. In the present study, we analyzed the role of zingerone against RAW 264.7 cells and acute lung injury induced by lipopolysaccharide (LPS) in mice. RAW cells or BALB/c mice were pretreated with zingerone one hour before stimulated with LPS. We found that zingerone significantly inhibited the production of LPS-induced proinflammatory cytokines in vitro and in vivo. When pretreated with zingerone, pulmonary histopathologic changes, as well as alveolar hemorrhage and neutrophil infiltration were substantially suppressed in lung tissues, with evidence of reduced myeloperoxidase (MPO) activity in murine acute lung injury model. The lung wet-to-dry weight (W/D) ratios, as the index of pulmonary edema, were markedly decreased by zingerone pretreatment. Furthermore, we demonstrated that zingerone attenuates the mitogen-activated protein kinases (MAPK) and nuclear factor-kappaB (NF-κB) signaling pathways through blocking the phosphorylation of ERK, p38/MAPK and IκBα, NF-κB/P65. These results suggest that zingerone may provide protective effects against LPS-induced ALI.

Paeonol suppresses lipopolysaccharide-induced inflammatory cytokines in macrophage cells and protects mice from lethal endotoxin shock.

Paeonol (2'-hydroxy-4'-methoxyacetophenone) is the main phenolic compound of the radix of Paeonia suffruticosa which has been used as traditional Chinese medicine. In this study, we primarily investigated the anti-inflammatory effects and the underlying mechanisms of paeonol in RAW macrophage cells; and based on these effects, we assessed the protective effects of paeonol on lipopolysaccharide-induced endotoxemia in mice. The in vitro study showed that paeonol regulated the production of TNF-α, IL-1ß, IL-6, and IL-10 via inactivation of IκBα, ERK1/2, JNK, and p38 MAPK. In mouse model of lipopolysaccharide-induced endotoxemia, pro- and anti-inflammatory cytokines are significantly regulated, and thus the survival rates of lipolysaccharide-challenged mice are improved by paeonol (150, 200, or 250 mg/kg). Therefore, paeonol has a beneficial activity against lipopolysaccharide-induced inflammation in RAW 264.7 cell and mouse models.

Protection of mice against lipopolysaccharide-induced endotoxic shock by pinocembrin is correlated with regulation of cytokine secretion.

Natural products have been used as potentially important sources of anti-inflammatory drugs. This study examined the effects of pinocembrin against lipopolysaccharide (LPS)-induced endotoxemia to ascertain whether pinocembrin could protect mice from ensuing death. Cytokine responses were also assessed in serum isolated from blood collected at 0, 2, 4, 6, 8, and 24 h after LPS administration of the mice (with or without drug treatment). The results showed that there was a lower production of TNFα, IL-6, and IL-1ß in the serum of LPS-challenged mice that had been pre-treated with pinocembrin. In addition, pre-treatment with pinocembrin improved host survival against the LPS-induced lethal endotoxemia. These results suggest that this new flavonoid could potentially be a novel candidate for preventing development/mitigation progression of septic shock.

Tubeimoside-1 attenuates LPS-induced inflammation in RAW 264.7 macrophages and mouse models.

CONTEXT: Acute lung injury (ALI), characterized by severe hypoxemia, pulmonary edema and neutrophil accumulation in the lung, is a common clinical problem associated with significant morbidity and mortality in shock, sepsis, ischemia reperfusion, etc. OBJECTIVE: In this study, we aimed at investigating the protective effect of tubeimoside-1 (TBMS1) on inflammation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and a LPS-induced in vivo lung injury model. MATERIALS AND METHODS: We evaluated the effect of TBMS1 on LPS-induced production of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1ß in the culture supernatants of RAW 264.7 cells by enzyme-linked immunosorbent assay. LPS (0.5 mg/kg) was instilled intranasally in phosphate-buffered saline to induce ALI, and the severity of pulmonary injury was evaluated 6 h after LPS challenge. RESULTS: TBMS1 significantly inhibited the production of the pro-inflammatory cytokines, TNF-α, IL-6 and IL-1ß in vitro and in vivo. Pretreatment with TBMS1 markedly attenuated the development of pulmonary edema, histological severities and inflammatory cells infiltration in mice with ALI. In addition, we further demonstrated that TBMS1 exerts an anti-inflammatory effect in vivo model of ALI through suppression of IκB activation and p38/extracellular signal-regulated kinase mitogen-activated protein kinases signaling in a dose-dependent manner. DISCUSSION AND CONCLUSION: Overall, our data suggest that TBMS1 inhibits inflammation both in vitro and in vivo, and may be a potential therapeutic candidate for the prevention of inflammatory diseases.

Angelicin regulates LPS-induced inflammation via inhibiting MAPK/NF-κB pathways.

BACKGROUND: Angelicin is a furocoumarin found in Psoralea corylifolia L. fruit. The purpose of this study was to investigate the protective ability of angelicin against inflammation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and LPS-induced in vivo acute lung injury model. MATERIALS AND METHODS: The concentrations of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6 in the culture supernatants of RAW 264.7 cells were determined 24 h after LPS administration. ALI was induced by intratracheal instillation of LPS. Six hours after LPS inhalation, bronchoalveolar lavage fluid and lung tissue samples were obtained for enzyme-linked immunosorbent assay, histologic, and Western blotting analyses. RESULTS: The results showed that pretreatment with angelicin markedly downregulated TNF-α and IL-6 levels in vitro and in vivo, and significantly decreased the amount of inflammatory cells, lung wet-to-dry weight ratio, and myeloperoxidase activity in LPS-induced ALI mice. Furthermore, Western blotting analysis results demonstrated that angelicin blocked the phosphorylation of IκBα, NF-κBp65, p38 MAPK, and JNK in LPS-induced ALI. CONCLUSIONS: These results suggest that angelicin was potentially advantageous to prevent inflammatory diseases by inhibiting NF-κB and MAPK pathways. Our data indicated that angelicin might be a potential new agent for prevention of inflammatory reactions and diseases in the clinic.

Phillyrin attenuates LPS-induced pulmonary inflammation via suppression of MAPK and NF-κB activation in acute lung injury mice.

Phillyrin (Phil) is one of the main chemical constituents of Forsythia suspensa (Thunb.), which has shown to be an important traditional Chinese medicine. We tested the hypothesis that Phil modulates pulmonary inflammation in an ALI model induced by LPS. Male BALB/c mice were pretreated with or without Phil before respiratory administration with LPS, and pretreated with dexamethasone as a control. Cytokine release (TNF-α, IL-1ß, and IL-6) and amounts of inflammatory cell in bronchoalveolar lavage fluid (BALF) were detected by ELISA and cell counting separately. Pathologic changes, including neutrophil infiltration, interstitial edema, hemorrhage, hyaline membrane formation, necrosis, and congestion during acute lung injury in mice were evaluated via pathological section with HE staining. To further investigate the mechanism of Phil anti-inflammatory effects, activation of MAPK and NF-κB pathways was tested by western blot assay. Phil pretreatment significantly attenuated LPS-induced pulmonary histopathologic changes, alveolar hemorrhage, and neutrophil infiltration. The lung wet-to-dry weight ratios, as the index of pulmonary edema, were markedly decreased by Phil pretreatment. In addition, Phil decreased the production of the proinflammatory cytokines including (TNF-α, IL-1ß, and IL-6) and the concentration of myeloperoxidase (MPO) in lung tissues. Phil pretreatment also significantly suppressed LPS-induced activation of MAPK and NF-κB pathways in lung tissues. Taken together, the results suggest that Phil may have a protective effect on LPS-induced ALI, and it potentially contributes to the suppression of the activation of MAPK and NF-κB pathways. Phil may be a new preventive agent of ALI in the clinical setting.

Protective effect of esculentoside A on lipopolysaccharide-induced acute lung injury in mice.

BACKGROUND: Esculentoside A (EsA) is a saponin isolated from the Chinese herb Phytolacca esculenta. In our study, we sought to investigate the protective effects of EsA on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. MATERIALS AND METHODS: To determine the effects of EsA on the reduction of histopathologic changes in mice with ALI, inflammatory cell count in bronchoalveolar lavage fluid (BALF) and lung wet-to-dry weight ratio were measured in LPS-challenged mice, and lung histopathologic changes observed via paraffin section were assessed. Next, cytokine production induced by LPS in BALF was measured by enzyme-linked immunosorbent assay. To further study the mechanism of EsA protective effects on ALI, IκBa, p38, and extracellular signal receptor-activated kinase pathways were investigated in lung tissue of mice with ALI. RESULTS: In the present investigation, EsA showed marked effects by reducing inflammatory infiltration, thickening of the alveolar wall, and pulmonary congestion. Levels of tumor necrosis factor α and interleukin 6 elevated by LPS were significantly decreased in BALF in EsA-pretreated ALI model. Furthermore, EsA significantly suppressed phosphorylation of IκBa, p38, and extracellular signal receptor-activated kinase. CONCLUSIONS: Taken together, our results suggest that EsA suppressed inflammatory responses in LPS-induced ALI through inhibition of the nuclear factor kappa B and mitogen activated protein kinase signaling pathways. EsA may be a promising potential preventive agent for ALI treatment.

Prime-O-glucosylcimifugin attenuates lipopolysaccharide-induced acute lung injury in mice.

Prime-O-glucosylcimifugin is an active chromone isolated from Saposhnikovia root which has been reported to have various activities, such as anti-convulsant, anticancer, anti-inflammatory properties. The purpose of this study was to evaluate the effect of prime-O-glucosylcimifugin on acute lung injury (ALI) induced by lipopolysaccharide in mice. BALB/c mice received intraperitoneal injection of Prime-O-glucosylcimifugin 1h before intranasal instillation (i.n.) of lipopolysaccharide (LPS). Concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and interleukin (IL)-6 in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). Pulmonary histological changes were evaluated by hematoxylin-eosin, myeloperoxidase (MPO) activity in the lung tissue and lung wet/dry weight ratios were observed. Furthermore, the mitogen-activated protein kinases (MAPK) signaling pathway activation and the phosphorylation of IκBα protein were determined by Western blot analysis. Prime-O-glucosylcimifugin showed promising anti-inflammatory effect by inhibiting the activation of MAPK and NF-κB signaling pathway.