Effects of Eugenol and Dehydrodieugenol B from Nectandra leucantha against Lipopolysaccharide (LPS)-Induced Experimental Acute Lung Inflammation.

Acute lung injury (ALI) is an important public health problem. The present work investigated whether dehydrodieugenol B treatment, a compound isolated from Brazilian plant Nectandra leucantha (Lauraceae), modulates experimental ALI and compared the observed effects to eugenol. Effects of dehydrodieugenol B in vitro in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells were evaluated. The lung and systemic inflammatory profile, lung function, and possible mechanisms involved in BALB/C male mice (6-8 weeks) with ALI induced by LPS instillation (5 mg/kg) was assayed. Dehydrodieugenol B did not affect the cell viability and inhibited the increase in NO release and IL-1ß and IL-6 gene expression induced by LPS. In vivo, both compounds reduced lung edema, inflammatory cells, and the IL-6 and IL-1 ß levels in bronchoalveolar lavage fluid, as well as reduced inflammatory cell infiltration and those positive to iNOS, MMP-9, and TIMP-1, and reduced the collagen content and the 8-isoprostane expression in lung tissue. Eugenol and dehydrodieugenol B also inhibited the phosphorylation of Jc-Jun-NH2 terminal Kinase (JNK), a signaling protein involved in the MAPKinase pathway. There was no effect of these compounds in lung function. Therefore, eugenol and dehydrodieugenol B ameliorates several features of experimental ALI and could be considered as a pharmacological tool to ameliorate acute lung inflammation.

Vesicular acetylcholine transport deficiency potentiates some inflammatory responses induced by diesel exhaust particles.

Endogenous acetylcholine (ACh), which depends of the levels of vesicular ACh transport (VAChT) to be released, is the central mediator of the cholinergic anti-inflammatory system. ACh controls the release of cytokine in different models of inflammation. Diesel exhaust particles (DEP) are one of the major environmental pollutants produced in large quantity by automotive engines in urban center. DEP bind the lung parenchyma and induce inflammation. We evaluated whether cholinergic dysfunction worsens DEP-induced lung inflammation. Male mice with decreased ACh release due to reduced expression of VAChT (VAChT-KD mice) were submitted to DEP exposure for 30 days (3 mg/mL of DEP, once a day, five days a week) or saline. Pulmonary function and inflammation as well as extracellular matrix fiber deposition were evaluated. Additionally, airway and nasal epithelial mucus production were quantified. We found that DEP instillation worsened lung function and increased lung inflammation. Higher levels of mononuclear cells were observed in the peripheral blood of both wild-type (WT) and VAChT-KD mice. Also, both wild-type (WT) and VAChT-KD mice showed an increase in macrophages in bronchoalveolar lavage fluid (BALF) as well as increased expression of IL-4, IL-6, IL-13, TNF-α, and NF-κB in lung cells. The collagen fiber content in alveolar septa was also increased in both genotypes. On the other hand, we observed that granulocytes were increased only in VAChT-KD peripheral blood. Likewise, increased BALF lymphocytes and neutrophils as well as increased elastic fibers in alveolar septa, airway neutral mucus, and nasal epithelia acid mucus were observed only in VAChT-KD mice. The cytokines IL-4 and TNF-α were also higher in VAChT-KD mice compared with WT mice. In conclusion, decreased ability to release ACh exacerbates some of the lung alterations induced by DEP in mice, suggesting that VAChT-KD animals are more vulnerable to the effects of DEP in the lung.

Prophylactic and therapeutic treatment with the flavonone sakuranetin ameliorates LPS-induced acute lung injury.

Sakuranetin is the main isolate flavonoid from Baccharis retusa (Asteraceae) leaves and exhibits anti-inflammatory and antioxidative activities. Acute respiratory distress syndrome is an acute failure of the respiratory system for which effective treatment is urgently necessary. This study investigated the preventive and therapeutic effects of sakuranetin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Animals were treated with intranasal sakuranetin 30 min before or 6 h after instillation of LPS. Twenty-four hours after ALI was induced, lung function, inflammation, macrophages population markers, collagen fiber deposition, the extent of oxidative stress, and the expression of matrix metalloprotease-9 (MMP-9), tissue inhibitor of MMP-9 (TIMP-1) and NF-κB were evaluated. The animals began to show lung alterations 6 h after LPS instillation, and these changes persisted until 24 h after LPS administration. Preventive and therapeutic treatment with sakuranetin reduced the neutrophils in the peripheral blood and in the bronchial alveolar lavage. Sakuranetin treatment also reduced macrophage populations, particularly that of M1-like macrophages. In addition, sakurnaetin treatment reduced keratinocyte-derived chemokines (IL-8 homolog) and NF-κB levels, collagen fiber formation, MMM-9 and TIMP-1-positive cells, and oxidative stress in lung tissues compared with LPS animals treated with vehicle. Finally, sakuranetin treatment also reduced total protein, and the levels of TNF-α and IL-1ß in the lung. This study shows that sakuranetin prevented and reduced pulmonary inflammation induced by LPS. Because sakuranetin modulates oxidative stress, the NF-κB pathway, and lung function, it may constitute a novel therapeutic candidate to prevent and treat ALI.

Effects of VAChT reduction and α7nAChR stimulation by PNU-282987 in lung inflammation in a model of chronic allergic airway inflammation.

The cholinergic anti-inflammatory pathway has been shown to regulate lung inflammation and cytokine release in acute models of inflammation, mainly via α7 nicotinic receptor (α7nAChR). We aimed to evaluate the role of endogenous acetylcholine in chronic allergic airway inflammation in mice and the effects of therapeutic nAChR stimulation in this model. We first evaluated lung inflammation and remodeling on knock-down mice with 65% of vesicular acetylcholine transport (VAChT) gene reduction (KDVAChT) and wild-type(WT) controls that were subcutaneously sensitized and then inhaled with ovalbumin(OVA). We then evaluated the effects of PNU-282987(0.5-to-2mg/kg),(α7nAChR agonist) treatment in BALB/c male mice intraperitoneal sensitized and then inhaled with OVA. Another OVA-sensitized-group was treated with PNU-282987 plus Methyllycaconitine (MLA,1 mg/kg, α7nAChR antagonist) to confirm that the effects observed by PNU were due to α7nAChR. We showed that KDVAChT-OVA mice exhibit exacerbated airway inflammation when compared to WT-OVA mice. In BALB/c, PNU-282987 treatment reduced the number of eosinophils in the blood, BAL fluid, and around airways, and also decreased pulmonary levels of IL-4,IL-13,IL-17, and IgE in the serum of OVA-exposed mice. MLA pre-treatment abolished all the effects of PNU-282987. Additionally, we showed that PNU-282987 inhibited STAT3-phosphorylation and reduced SOCS3 expression in the lung. These data indicate that endogenous cholinergic tone is important to control allergic airway inflammation in a murine model. Moreover, α7nAChR is involved in the control of eosinophilic inflammation and airway remodeling, possibly via inhibition of STAT3/SOCS3 pathways. Together these data suggest that cholinergic anti-inflammatory system mainly α7nAChR should be further considered as a therapeutic target in asthma.

Corrigendum: Galloyl-Hexahydroxydiphenoyl (HHDP)-Glucose Isolated From Punica granatum L. Leaves Protects Against Lipopolysaccharide (LPS)-Induced Acute Lung Injury in BALB/c Mice.

[This corrects the article DOI: 10.3389/fimmu.2019.01978.].

Galloyl-Hexahydroxydiphenoyl (HHDP)-Glucose Isolated From Punica granatum L. Leaves Protects Against Lipopolysaccharide (LPS)-Induced Acute Lung Injury in BALB/c Mice.

The hydroalcoholic extract and ethyl acetate fraction of Punica granatum leaves have been known to exhibit anti-inflammatory activities. In this study, we investigated the therapeutic effects of galloyl-hexahydroxydiphenoyl (HHDP)-glucose isolated from pomegranate leaves on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Male BALB/c mice were treated with different doses of galloyl-HHDP-glucose (5, 50, and 100 mg/Kg) or dexamethasone at 5 mg/Kg (per os) 6 h after intra-tracheal instillation of LPS. Vehicle-treated mice were used as controls. Twenty-four hours after LPS challenge, bronchoalveolar lavage fluid (BALF), and lung samples were collected for analyses. They were evaluated by monitoring the expression of NF-κB, JNK, and cytokine genes and proteins, as well as cell migration and lung function. All doses of galloyl-HHDP-glucose inhibited LPS-induced JNK and NF-κB activation. Likewise, the galloyl-HHDP-glucose-treated animals presented reduced expression of the TNF-α, IL-6, and IL-1ß genes in the lungs and reduced TNF-α, IL-6, IL-1ß, and IL-8 protein levels when compared with the vehicle-treated LPS-challenged mice. In addition, the ALI mice treated with galloyl-HHDP-glucose also presented reduced lung inflammatory cell accumulation, especially that of neutrophils, in their BALF and lungs. In addition, galloyl-HHDP-glucose treatment markedly ameliorated the LPS-induced pulmonary mechanism complications and attenuated weight loss. Overall, we showed for the first time that galloyl-HHDP-glucose protects against ALI, and may be useful for treating ALI and other inflammatory disorders.