Sauchinone, a lignan from Saururus chinensis, attenuates neutrophil pro-inflammatory activity and acute lung injury

Long noncoding RNA signatures in intrauterine infection/inflammation-induced lung injury: an integrative bioinformatics study

BACKGROUND

Intrauterine infection/inflammation can result in fetal and neonatal lung injury. However, the biological mechanisms of intrauterine infection/inflammation on fetal and neonatal lung injury and development are poorly known. To date, there are no reliable biomarkers for improving intrauterine infection/inflammation-induced lung injury.

METHODS

An animal model of intrauterine infection/inflammation-induced lung injury was established with pregnant Sprague-Dawley rats inoculated with Escherichia coli suspension. The intrauterine inflammatory status was assessed through the histological examination of the placenta and uterus. A serial of histological examinations of the fetal and neonatal rats lung tissues were performed. The fetal and neonatal rat lung tissues were harvested for next generation sequencing at embryonic day 17 and postnatal day 3, respectively. Differentially expressed mRNAs and lncRNAs were identified by conducting high-throughput sequencing technique. The target genes of identified differentially expressed lncRNAs were analyzed. Homology analyses for important differentially expressed lncRNAs were performed.

RESULTS

The histopathological results showed inflammatory infiltration, impaired alveolar vesicular structure, less alveolar numbers, and thickened alveolar septa in fetal and neonatal rat lung tissues. Transmission electron micrographs revealed inflammatory cellular swelling associated with diffuse alveolar damage and less surfactant-storing lamellar bodies in alveolar epithelial type II cells. As compared with the control group, there were 432 differentially expressed lncRNAs at embryonic day 17 and 125 differentially expressed lncRNAs at postnatal day 3 in the intrauterine infection group. The distribution, expression level, and function of these lncRNAs were shown in the rat genome. LncRNA TCONS_00009865, lncRNA TCONS_00030049, lncRNA TCONS_00081686, lncRNA TCONS_00091647, lncRNA TCONS_00175309, lncRNA TCONS_00255085, lncRNA TCONS_00277162, and lncRNA TCONS_00157962 may play an important role in intrauterine infection/inflammation-induced lung injury. Fifty homologous sequences in Homo sapiens were also identified.

CONCLUSIONS

This study provides genome-wide identification of novel lncRNAs which may serve as potential diagnostic biomarkers and therapeutic targets for intrauterine infection/inflammation-induced lung injury.

Natural products in attenuating renal inflammation via inhibiting the NLRP3 inflammasome in diabetic kidney disease

Diabetic kidney disease (DKD) is a prevalent and severe complications of diabetes and serves as the primary cause of end-stage kidney disease (ESKD) globally. Increasing evidence indicates that renal inflammation is critical in the pathogenesis of DKD. The nucleotide - binding oligomerization domain (NOD) - like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most extensively researched inflammasome complex and is considered a crucial regulator in the pathogenesis of DKD. The activation of NLRP3 inflammasome is regulated by various signaling pathways, including NF- κB, thioredoxin-interacting protein (TXNIP), and non-coding RNAs (ncRNA), among others. Natural products are chemicals extracted from living organisms in nature, and they typically possess pharmacological and biological activities. They are invaluable sources for drug design and development. Research has demonstrated that many natural products can alleviate DKD by targeting the NLRP3 inflammasome. In this review, we highlight the role of the NLRP3 inflammasome in DKD, and the pathways by which natural products fight against DKD via inhibiting the NLRP3 inflammasome activation, so as to provide novel insights for the treatment of DKD.

A critical review on anti-fibrotic phytochemicals targeting activated hepatic stellate cells

Liver fibrosis is a major health concern occurring worldwide. It arises due to prolonged wound healing response of various insults like viral, autoimmune, cholestatic, drug-induced, and metabolic diseases. Currently, there is no clinically approved drug for liver fibrosis treatment. Hepatic stellate cells are the principal liver cells that are activated during liver fibrosis, and targeting these activated cells is an ideal therapeutic strategy. Numerous phytochemicals have been demonstrated in vitro and in vivo treating experimental liver fibrosis; however, none of them have been clinically approved for therapeutic use. This review mainly focuses on such hepatoprotective phytochemicals reported inhibiting major signaling pathways that are dysregulated in activated hepatic stellate cells. PRACTICAL APPLICATIONS: Liver fibrosis is a global health concern and there is no FDA approved drug to treat liver fibrosis. Although notable pharmacological agents like pentoxifylline, gliotoxin, imatinibmesylate, Gleevec, and so on are reported to exhibit anti-fibrotic effect, the major concern is their side effect. Hence, phytochemicals are promising candidates that could be employed against liver fibrosis. In this review, the anti-fibrotic potential of phytochemicals targeting activated HSCs are summarized. Understanding these phytochemicals will further help in the development of agents that are more effective against liver fibrosis.

Meso-Dihydroguaiaretic Acid Ameliorates Acute Respiratory Distress Syndrome through Inhibiting Neutrophilic Inflammation and Scavenging Free Radical

The pathogenesis of acute respiratory distress syndrome (ARDS) is very complex. Patients with ARDS still suffer high mortality rates. Infiltration and activation of neutrophils in lungs are critical pathogenic factors in ARDS. In this study, we demonstrate that meso-dihydroguaiaretic acid (MDGA), a natural lignan, inhibits inflammatory responses in human neutrophils and ameliorates ARDS in mice. MDGA inhibited superoxide anion generation and elastase release in various G-protein coupled receptor agonists-induced human neutrophils. However, MDGA did not alter superoxide anion generation and elastase activity in cell-free systems. These results suggest that the anti-inflammatory effects of MDGA are mediated by regulating cellular signals in human neutrophils. In consistent with this, MDGA suppressed phosphorylation of extracellular signal-regulated kinase and c-Jun N-terminal kinase in activated human neutrophils. Moreover, MDGA inhibited CD11b expression and adhesion in activated human neutrophils. Interestingly, MDGA reduced reactive oxygen species (ROS) generation but not superoxide anion generation in protein kinase C (PKC) activator-induced human neutrophils, suggesting that MDGA may also have ROS scavenging ability. Indeed, MDGA showed strong free radical scavenging activity in cell-free assays. Significantly, MDGA suppressed PKC-induced neutrophil extracellular trap formation. Additionally, treatment of MDGA attenuated neutrophil infiltration and lung damage on lipopolysaccharide-induced ARDS in mice. In conclusion, our results demonstrate that MDGA has anti-neutrophilic inflammatory effects and free-radical scavenging activity. We also suggest that MDGA has potential to serve as a lead for developing new therapeutics to treat ARDS.

Sauchinone inhibits the proliferation, migration and invasion of breast cancer cells by suppressing Akt-CREB-MMP13 signaling pathway

Sauchinone, a lignan isolated from Saururus chinenesis, is known to exhibit anti-inflammatory and anti-oxidant effects. Recently, sauchinone has been reported to inhibit the growth of various cancer cells, but its effects on breast cancer cells remain poorly understood. In the present study, we investigated the effects of sauchinone on the growth of breast cancer cells along with the underlying molecular mechanisms. Our results show that sauchinone treatment markedly inhibited the proliferation, migration, and invasion of breast cancer cells. Sauchinone reduced the phosphorylation of Akt, ERK, and CREB increased by transforming growth factor-β (TGF-β). In particular, sauchinone treatment suppressed the expression of matrix metalloproteinase (MMP)-13 (MMP13) by regulating the Akt-CREB signaling pathway. Sauchinone was less effective in inhibiting cell migration in Mmp13-knockdown cells than in control cells, suggesting that MMP13 may be a novel target for sauchinone. Our study suggests that sauchinone inhibits the growth of breast cancer cells by attenuating the Akt-CREB-MMP13 pathway. In addition, the targeted inhibition of MMP13 by sauchinone represents a promising approach for the treatment of breast cancer.

TAK1 in the AP-1 pathway is a critical target of Saururus chinensis (Lour.) Baill in its anti-inflammatory action

ETHNOPHARMACOLOGICAL RELEVANCE

Saururus chinensis (Lour.) Baill (Saururaceae), also known as Asian lizard's tail, is a plant commonly found in East Asia. Its leaves have been used in traditional medicine to treat many diseases such as edema, pneumonia, hypertension, leproma, jaundice, gonorrhea, and rheumatoid arthritis.

AIM OF THE STUDY

Based on the efficacies of S. chinensis, the anti-inflammatory effects of this plant and the molecular mechanism were evaluated using the ethanol extract of S. chinensis leaves (Sc-EE).

MATERIALS AND METHODS

The production of pro-inflammatory mediators and cytokines in response to Sc-EE was evaluated using Griess and semi-quantitative reverse transcription-polymerase chain reactions. Furthermore, relevant proteins including c-Jun, c-Fos, p38, JNK, ERK, MEK1/2, MKK3/6, MKK4/7, and TAK1 were detected through immunoblotting.

RESULTS

Sc-EE diminished production of nitric oxide (NO); decreased expression levels of cyclooxygenase (COX)-2, interleukin (IL)-6, inducible NO synthase (iNOS), and IL-1β in LPS-stimulated RAW264.7 cells; and attenuated activator protein 1 (AP-1)-mediated luciferase activities. The extract markedly downregulated the phosphorylation of TAK1, upregulated thermal stability of TAK1, and reduced TAK1/AP-1-mediated luciferase activity in LPS-treated RAW264.7 cells and TAK1-overexpressing HEK293T cells.

CONCLUSIONS

These results demonstrated that Sc-EE suppresses pro-inflammatory gene expression through blockade of the TAK1/AP-1 pathway in LPS-treated RAW264.7 macrophages, implying that inhibition of TAK1/AP-1 signaling by S. chinensis is a key event in its anti-inflammatory activity.

SB203580 attenuates acute lung injury and inflammation in rats with acute pancreatitis in pregnancy

Acute pancreatitis in pregnancy (APIP) can lead to multiple maternal and fetal organ injury and mitogen-activated protein kinase (MAPK) signaling pathway may be involved in it; however, whether APIP can result in acute lung injury and P38MAPK signaling pathway is involved in the pathogenesis has not been elucidated. The present study was undertaken to investigate the participation of P38MAPK signaling pathway and the protective effect of SB203580, an inhibitor of P38MAPK on acute lung injury induced by APIP. Twenty-four late-gestation SD rats were randomly assigned to four groups: Sham operation (SO) group, SB302580 (SB) group, APIP group, and SB + APIP group. All the rats were killed 6 h after modeling. The severity of pancreatitis was evaluated by serum amylase (AMY) and lipase (LIPA) and histopathological changes. Histological assessment of the lung and inflammatory cell infiltration was performed by H&E and immunofluorescence assay. The lung wet/dry (W/D) weight ratio was determined, and the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were detected by enzyme-linked immunosorbent assay (ELISA). Western blot analysis was used to detect the protein expression of phosphorylated and total P38, tumor necrosis factor (TNF)-α, and intercellular adhesion molecules 1 (ICAM-1) in lung tissues. Obvious pathological changes existed in pancreas and lung after the induction of APIP, and their pathological scores were significantly higher than that of control group. The results showed that the phosphorylation of P38MAPK was elevated in the lung of APIP rats. Compared with APIP group, the intervention of SB203580 alleviated the pathological injury of the pancreas and lungs, decreased serum AMY and LIPA, attenuated the secretion of TNF-α, IL-1β, and IL-6 in lung, reduced the inflammatory cells' infiltration and lung W/D ratio and inhibited the activation of P38MAPK signaling pathway. These results suggest that APIP can lead to acute lung injury and inflammation and SB203580 can inhibit the lung injury by inhibiting the P38MAPK signaling pathway and blocking the inflammatory responses.

Artemisia argyi attenuates airway inflammation in lipopolysaccharide induced acute lung injury model

Artemisia argyi is used as a health supplement, tea, and food source in Korea. This study aimed to evaluate the effect of Artemisia argyi (AA) and its active compound, dehydromatricarin A (DA), on the attenuation of airway inflammation in a murine model of lipopolysaccharide (LPS)-induced acute lung injury (ALI). The C57BL/6 mice were administered AA (50 mg/kg or 100 mg/kg) and DA (10 mg/kg or 20 mg/kg) by oral gavage from day 0 to 7 days and LPS treated by intranasal instillation 48 hours before the sacrifice. The treatment of AA and DA markedly decreased inflammatory cells in the bronchoalveolar lavage fluid (BALF) compared with that in ALI-induced mice, which was accompanied by a significant reduction in the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in BALF. Furthermore, the administration of AA and DA clearly decreased inducible nitric oxide synthase (iNOS) expression and nuclear factor kappa B (NF-κB) phosphorylation in comparison with that in the ALI-induced mice. The histological examination of the lung tissue revealed that the administration of AA and DA suppressed the inflammatory cell infiltration into the peribronchial and alveolar lesions induced by LPS instillation. Collectively, our results indicated that AA and DA effectively decreased the airway inflammatory response induced by LPS instillation. Therefore, AA and DA may offer a potential therapy for airway inflammatory disease.

miR-127 contributes to ventilator-induced lung injury

Although it is essential in critical care medicine, mechanical ventilation often results in ventilator‑induced lung injury (VILI). Treating mice with lipopolysaccharide has been reported to upregulate the expression of miR‑127, which has been implicated in the modulation of immune responses. However, the putative roles of miR‑127 during the development of VILI have yet to be elucidated. The present study demonstrated that challenging mice with mechanical ventilation for 6 h significantly upregulated the expression of miR‑127 in bronchoalveolar lavage fluid, serum and lung tissue samples. Conversely, following the downregulation of miR‑127 expression in vivo using an adenovirus delivery system, VILI‑associated pathologies, including alterations in the pulmonary wet/dry ratio, pulmonary permeability, lung neutrophil infiltration and levels of pro‑inflammatory cytokines, were significantly attenuated. In addition, miR‑127 knockdown inhibited the ventilation‑induced activation of nuclear factor (NF)‑κB and p38 mitogen‑activated protein kinase (MAPK). These findings suggested that the upregulation of miR‑127 expression may contribute to the development of VILI, through the modulation of pulmonary permeability, the induction of histopathological alterations, and the potentiation of inflammatory responses involving NF‑κB and p38 MAPK‑associated signaling pathways.

Lipopolysaccharide-Binding Protein Downregulates Fractalkine through Activation of p38 MAPK and NF-κB

Background

LBP and fractalkine are known to be involved in the pathogenesis of ARDS. This study investigated the relationship between LBP and fractalkine in LPS-induced A549 cells and rat lung tissue in an ARDS rat model.

Methods

A549 cells were transfected with LBP or LBP shRNA plasmid DNA or pretreated with SB203580 or SC-514 following LPS treatment. An ARDS rat model was established using LPS with or without LBPK95A, SB203580, or SC-514 treatment. RT-PCR, western blotting, ELISA, immunofluorescence, coimmunoprecipitation, and immunohistochemical staining were used to study the expression of fractalkine and LBP and p38 MAPK and p65 NF-κB activities.

Results

LPS increased LBP and reduced fractalkine. LBP overexpression further decreased LPS-induced downregulation of fractalkine and p38 MAPK and p65 NF-κB activation; LBP gene silencing, SB203580, and SC-514 suppressed LPS-induced downregulation of fractalkine and p38 MAPK and p65 NF-κB activation in A549 cells. LBP and fractalkine in lung tissue were increased and decreased, respectively, following LPS injection. LBPK95A, SB203580, and SC-514 ameliorated LPS-induced rat lung injury and suppressed LPS-induced downregulation of fractalkine by decreasing phospho-p38 MAPK and p65 NF-κB.

Conclusions

The results indicate that LBP downregulates fractalkine expression in LPS-induced A549 cells and in an ARDS rat model through activation of p38 MAPK and NF-κB.

AICAR Enhances the Phagocytic Ability of Macrophages towards Apoptotic Cells through P38 Mitogen Activated Protein Kinase Activation Independent of AMP-Activated Protein Kinase

Recent studies have suggested that 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) increases macrophage phagocytosis through adenosine monophosphate-activated protein kinase (AMPK). However, little information is available on the effects of AICAR on the clearance of apoptotic cells by macrophages, known as efferocytosis, which is essential in maintaining tissue homeostasis and resolving inflammation. AICAR increased p38 MAPK activation and the phagocytosis of apoptotic cells by macrophages, which were inhibited by the p38 MAPK inhibitor, SB203580, the TGF-beta-activated kinase 1 (TAK1) inhibitor, (5Z)-7-oxozeaenol, and siRNA-mediated knock-down of p38α. AICAR increased phosphorylation of Akt, but the inhibition of PI3K/Akt activity using LY294002 did not affect the AICAR-induced changes in efferocytosis in macrophages. CGS15943, a non-selective adenosine receptor antagonist, did not affect AICAR-induced changes in efferocytosis, but dipyridamole, an adenosine transporter inhibitor, diminished the AICAR-mediated increases in efferocytosis. AICAR-induced p38 MAPK phosphorylation was not inhibited by the AMPK inhibitor, compound C, or siRNA-mediated knock-down of AMPKα1. Inhibition of AMPK using compound C or 5’-iodotubercidin did not completely block AICAR-mediated increases in efferocytosis. Furthermore, AICAR also increased the removal of apoptotic neutrophils or thymocytes in mouse lungs. These results reveal a novel mechanism by which AICAR increases macrophage-mediated phagocytosis of apoptotic cells and suggest that AICAR may be used to treat efferocytosis-related inflammatory conditions.

Regulatory effects of hydrogen sulfide on alveolar epithelial cell endoplasmic reticulum stress in rats with acute lung injury

BACKGROUND

The present study was undertaken to examine the regulatory effect of hydrogen sulfide (H2S) on endoplasmic reticulum stress in alveolar epithelial cells of rats with acute lung injury (ALI) induced by oleic acid (OA).

METHODS

Seventy-two male Sprague Dawley (SD) rats were divided into control group, oleic acid-induced ALI group (OA group), oleic acid-induced ALI with sodium hydrosulfide (NaHS) pretreatment group (OA+NaHS group), and sodium hydrosulfide treatment group (NaHS group). Rats of each group were further subdivided into 3 subgroups. Index of quantitative assessment of histological lung injury (IQA), wet/dry weight ratio (W/D) and H2S level of lung tissues were measured. The expressions of endoplasmic reticulum stress markers including glucose-regulated protein 78 (GRP78) and α-subunit of eukaryotic translation initiation factor-2 (elF2α) in lung tissues were measured by immunohistochemical staining and Western blotting.

RESULTS

The IQA score and W/D ratio of lung tissues at the three time points significantly increased in rats injected with OA, but significantly decreased in other rats injected with OA and NaHS. The level of H2S in lung tissue at the three time points significantly decreased in rats injected with OA, but significantly increased in other rats injected with both OA and NaHS. GRP78 and elF2α decreased in rats injected with OA, but increased in other rats injected with both OA and NaHS, especially at 4-hour and 6-hour time points.

CONCLUSION

The results suggested that H2S could promote alveolar epithelial cell endoplasmic reticulum stress in rats with ALI.

Attenuation of inflammatory-mediated neurotoxicity by Saururus chinensis extract in LPS-induced BV-2 microglia cells via regulation of NF-κB signaling and anti-oxidant properties

Background

A Saururus chinensis Baill (SC) has been used by Native Americans, early colonists and practitioners of Korean traditional medicine for treating several diseases including cancer, rheumatoid arthritis and edema. The objective of this study was to evaluate the effects of SC extract in lipopolysaccharide (LPS)-stimulated neuroinflammatory responses in BV-2 microglial cells.

Methods

The effects of SC on the LPS–induced neuroinflammatory responses in BV-2 microglial cells were assessed by Western blotting, RT-PCR and immunofluorescence labeling techniques. DPPH and alkyl radical scavenging assay was performed to evaluate the anti-oxidant effects. Comparisons between groups were analyzed using one-way analysis of variance followed by Dunnett’s multiple comparisons test using GraphPad Prism V5.01 software.

Results

Pre-treatment with SC extract (1, 5 and 10 μg/mL) significantly (p < 0.001 at 10 μg/mL) and concentration dependently inhibited LPS-induced production of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and suppressed the inflammatory cytokine levels such as tumor necrosis factor-alpha and interleukin (IL)-6 in BV-2 microglial cells (p < 0.001 at 10 μg/mL). Further, SC suppressed the nuclear factor-kappa B (NF-κB) activation by blocking the degradation of IκB-α. SC also exhibited profound anti-oxidant effects by scavenging 1, 1-diphenyl-2-picrylhydrazyl (DPPH) (IC50: 0.055 mg/mL) and alkyl radicals (IC50: 0.349 mg/mL). High performance liquid chromatography finger printing analysis of SC revealed quercetin (QCT) as one of the major constituents compared with reference standard. QCT also inhibited the excessive release of NO, and inhibited the increased expressional levels of IL-6, iNOS and COX-2 in LPS-stimulated BV-2 cells.

Conclusions

Our results indicated that SC inhibited the LPS-stimulated neuroinflammatory responses in BV-2 microglia via regulation of NF-κB signaling. The antioxidant active constituents of SC might be partly involved in delivering such effects. Based on the traditional claims and our present results SC can be potentially used in treating inflammatory-mediated neurodegenerative diseases.

Effect of sauchinone, a lignan from Saururus chinensis, on bacterial phagocytosis by macrophages

AMP-activated protein kinase (AMPK) plays an important role in inflammation in various cells and increases the phagocytic ability of macrophages. In this study, we found that sauchinone increased the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC), a downstream target of AMPK, in mouse peritoneal macrophages. Sauchinone increased macrophage phagocytosis of fluorescent Escherichia coli, which was blocked by compound C, an AMPK inhibitor. Sauchinone also increased the phosphorylation of p38 mitogen activated protein kinase (MAPK) in cultured macrophages in a concentration-dependent fashion, which was not blocked by compound C. However, the increase of sauchinone-induced phagocytosis was prevented by SB203580. An inhibitor of the upstream kinase TGF-beta-activated kinase (TAK1), (5z)-7-oxozeaenol, abolished the phosphorylation of ACC and p38 MAPK. Systemic administration of sauchinone to mice led to increased phosphorylation of AMPK and p38 MAPK in the lung, and enhanced phagocytosis of fluorescent E. coli in bronchoalveolar lavage fluid as compared with control mice. These results suggest sauchinone to be a useful adjunctive treatment for bacterial infection.

Medicinal plants, human health and biodiversity: a broad review

Biodiversity contributes significantly towards human livelihood and development and thus plays a predominant role in the well being of the global population. According to WHO reports, around 80 % of the global population still relies on botanical drugs; today several medicines owe their origin to medicinal plants. Natural substances have long served as sources of therapeutic drugs, where drugs including digitalis (from foxglove), ergotamine (from contaminated rye), quinine (from cinchona), and salicylates (willow bark) can be cited as some classical examples.Drug discovery from natural sources involve a multifaceted approach combining botanical, phytochemical, biological, and molecular techniques. Accordingly, medicinal-plant-based drug discovery still remains an important area, hitherto unexplored, where a systematic search may definitely provide important leads against various pharmacological targets.Ironically, the potential benefits of plant-based medicines have led to unscientific exploitation of the natural resources, a phenomenon that is being observed globally. This decline in biodiversity is largely the result of the rise in the global population, rapid and sometimes unplanned industrialization, indiscriminate deforestation, overexploitation of natural resources, pollution, and finally global climate change.Therefore, it is of utmost importance that plant biodiversity be preserved, to provide future structural diversity and lead compounds for the sustainable development of human civilization at large. This becomes even more important for developing nations, where well-planned bioprospecting coupled with nondestructive commercialization could help in the conservation of biodiversity, ultimately benefiting mankind in the long run.Based on these findings, the present review is an attempt to update our knowledge about the diverse therapeutic application of different plant products against various pharmacological targets including cancer, human brain, cardiovascular function, microbial infection, inflammation, pain, and many more.