The Effect of Epigallocatechin Gallate on Lipopolysaccharide-Induced Acute Lung Injury in a Murine Model

Exploration of the anti-inflammatory potential of Polygonum bistorta L.: protection against LPS-induced acute lung injury in rats via NF-ĸβ pathway inhibition

Traditional medicine uses the roots and rhizomes of Polygonum bistorta L. (Polygonaceae) to treat cough, bronchitis, and other respiratory infections. Our goal was to gain insights into the lung protective effects of the roots of P. bistorta L. against lipopolysaccharide-induced acute lung injury in rats, along with the possible mechanism(s). The outcomes revealed deliberate quantities of the total phenolic and flavonoid contents of 156.2 ± 5.13 GAE/g and 179.45 ± 2.08 mg QE/g, respectively. Crude extract possesses a maximum inhibitory potential of 81.77% ± 0.62% for acetylcholinesterase against eserine. Acute oral toxicity study revealed LD50 beyond 7 g/kg. Plant extract markedly restored LPS-induced hypoxemia, pulmonary edema, histopathological alterations, and leukocyte infiltration in the lung. ELISA testing on BALF found that the plant extract efficiently reinstated superoxide dismutase, total anti-oxidant capacity, malondialdehyde, and total oxidative stress. qRT-PCR indicated a decline in the endotoxin-induced overproduction of pro-inflammatory markers, oxidative stress, transcription factor, and downregulated antioxidant potential in extract-treated groups. Furthermore, 24 metabolites were identified and quantified via GC-MS. A molecular docking procedure was implemented on the bioactive metabolites that were identified to evaluate their potential for inhibiting AChE. In conclusion, P. bistorta roots mitigate inflammation and oxidative stress by improving redox signaling and NF-ĸβ (p65) pathways and can thus play a role in strategies for overcoming therapeutic challenges.

The polysaccharide from purple sweet potato (Ipomoea batatas (L.) Lam) alleviates lipopolysaccharide-induced acute lung injury in mice via the VIP/cAMP/PKA/AQPs signaling pathway

BACKGROUND

The polysaccharide (PSP) from purple sweet potato has great potential for regulating apoptosis, but its regulatory role in acute lung injury (ALI) is unknown.

METHODS

The objective of this study was to investigate the protective effect of PSP on lipopolysaccharide (LPS)-induced ALI in mice and lung epithelial A549 cells and its mechanism. Moreover, subacute toxicity evaluation of PSP was carried out on ICR mice.

RESULTS

The results showed that compared with the ALI group, PSP significantly reduced the total protein content, wet-to-dry (W/D) ratio, the number of neutrophils, lymphocytes, and monocytes. Moreover, PSP was able to reduce cell apoptosis, the levels of macrophage inflammatory protein-2 (MIP-2), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA) and myeloperoxidase (MPO) and increase the level of superoxide (SOD). In addition, PSP could up-regulate the levels of VIP, cAMP, p-PKA/PKA and AQP1 in mice and A549 cells. And PSP exhibited no apparent adverse effects on the mice.

CONCLUSIONS

PSP had a protective effect on LPS-induced ALI in mice and lung epithelial A549 cells, which may be related to the inflammatory response and via VIP/cAMP/PKA/AQPs signaling pathway. Thus, PSP may be a promising pharmacologic agent for ALI therapy.

FTO Deficiency Alleviates LPS-induced Acute Lung Injury by TXNIP/NLRP3-mediated Alveolar Epithelial Cell Pyroptosis

N6-methyladenosine (m6A) plays a role in various diseases, but it has rarely been reported in acute lung injury (ALI). The FTO (fat mass and obesity-associated) protein can regulate mRNA metabolism by removing m6A residues. The aim of this study was to examine the role and mechanism of the m6A demethylase FTO in LPS-induced ALI. Lung epithelial FTO-knockout mice and FTO-knockdown/overexpression human alveolar epithelial (A549) cell lines were constructed to evaluate the effects of FTO on ALI. Bioinformatics analysis and a series of in vivo and in vitro assays were used to examine the mechanism of FTO regulation. Rescue assays were conducted to examine whether the impact of FTO on ALI depended on the TXNIP/NLRP3 pathway. In LPS-induced ALI, RNA m6A modification amounts were upregulated, and FTO expression was downregulated. In vivo, lung epithelial FTO knockout alleviated alveolar structure disorder, tissue edema, and pulmonary inflammation and improved the survival of ALI mice. In vitro, FTO knockdown reduced A549 cell damage and death induced by LPS, whereas FTO overexpression exacerbated cell damage and death. Mechanistically, bioinformatics analysis revealed that TXNIP was a downstream target of FTO. FTO deficiency mitigated pyroptosis in LPS-induced ALI via the TXNIP/NLRP3 pathway. Rescue assays confirmed that the impact of FTO on the TXNIP/NLRP3 pathway was significantly reversed by the TXNIP inhibitor SRI-37330. Deficiency of FTO alleviates LPS-induced ALI via TXNIP/NLRP3 pathway-mediated alveolar epithelial cell pyroptosis, which might be a novel therapeutic strategy for combating ALI.

LncRNA 220, a newly discovered long non-conding RNA inhibiting apoptosis and autophagy in Kupffer cells in LPS-induced endotoxemic mice through the XBP1u-PI3K-AKT pathway

Sepsis is recognized as a potentially fatal condition characterized by acute organ dysfunction resulting from an imbalanced immune response to infection. Acute liver injury (ALI) arises as an inflammatory outcome of immune response dysregulation associated with sepsis. Kupffer cells, which are liver-specific macrophages, are known to have a significant impact on ALI, although the precise regulatory mechanism remains unclear. Numerous studies have showcased the regulatory impact of long non-coding RNAs (lncRNAs) on the progression of diverse ailments, yet their precise regulatory mechanisms remain predominantly unexplored. In this study, a novel long non-coding RNA (lncRNA), referred to as lncRNA 220, was discovered using high-throughput sequencing. The expression of lncRNA 220 was found to be significantly elevated in the livers of mice with lipopolysaccharide (LPS)-induced endotoxemia, specifically during the 8-hour time period. Furthermore, in Kupffer cells treated with LPS, lncRNA 220 was observed to inhibit apoptosis and autophagy by activating the PI3K-AKT-mTORC1 pathway. This effect was achieved through the reduction of X-box protein 1 unspliced (Xbp1u) mRNA stability and suppression of its translation in the context of endoplasmic reticulum stress (ERS). Ultimately, this intervention mitigated the progression of LPS-induced ALI. To summarize, our study establishes lncRNA 220 as a newly identified regulator that suppresses apoptosis and autophagy in Kupffer cells subjected to LPS treatment, indicating its potential as a molecular target for ALI in endotoxemic mice.

Fe-Capsaicin Nanozymes Attenuate Sepsis-Induced Acute Lung Injury via NF-κB Signaling

Background

In sepsis, the lungs are one of the most severely affected organs, usually resulting in acute lung injury (ALI). Capsaicin (CAP) is a natural compound found in chili peppers that has pain-relieving and anti-inflammatory properties. Here, we report that nanoparticles containing capsaicin and iron (Fe-CAP NPs) exhibited anti-inflammatory effects in the treatment of ALI.

Methods

The morphological characteristics of nanozymes were detected. RAW 264.7 cells were divided into four groups: control, lipopolysaccharide (LPS), CAP+LPS and Fe-CAP+LPS groups. The expression of inducible nitric oxide synthase (iNOS), transforming growth factor-β (TGF-β), and tumor necrosis factor-α (TNF-α) was assessed by immunofluorescence, Western blot, and enzyme-linked immunosorbent assay (ELISA). Nuclear factor kappa-B (NF-κB) expression was determined by Western blot. C57 mice were divided into control, LPS, CAP+LPS and Fe-CAP+LPS groups. Interleukin-6 (IL-6) and iNOS expression in the lung was detected by Western Blot. IL-6 and TNF-α expression in serum was detected by ELISA. Extravasated Evans blue, histopathological evaluation and wet-to-dry (W/D) weight ratio were used to assess pulmonary capillary permeability. The blood and major organs (heart, liver, spleen, lung and kidney) of mice were tested for the toxicity of Fe-CAP NPs.

Results

In the LPS group, TNF-α, iNOS, p-NF-κB and p-IKBα expression increased. However, their expression was significantly decreased in the Fe-CAP+LPS group. TGF-β expression showed the opposite trend. In vivo, IL-6 and iNOS expression was notably increased in the lungs of LPS group of mice but decreased with Fe-CAP pretreatment. Fe-CAP significantly ameliorated lung EB leakage, improved the histopathology of lung tissue and reduced the W/D weight ratio. The nanoparticles showed non-cytotoxicity, when studying these biological activities.

Conclusion

Fe-CAP NPs could alleviated inflammation by inhibiting the expression of pro-inflammatory factors in macrophages, increasing the expression of anti-inflammatory factors, and alleviating lung tissue damage.

Human Umbilical Cord Mesenchymal Stem Cell Exosome-derived miR-335-5p Alleviated Lipopolysaccharide-induced Acute Lung Injury by Regulating the m6A Level of ITGβ4 Gene

BACKGROUND

Acute lung injury (ALI) is a serious complication that may accompany severe pneumonia in children. Derived from human umbilical cord mesenchymal stem cell exosome (HucMSC-Exo) can contribute to the regeneration of damaged lung tissue. This study aims to investigate the impact of HucMSC-Exo on ALI and its potential mechanisms.

METHODS

Firstly, RT-qPCR was performed to assess the expression of miR-335-5p. Subsequently, Pearson correlation analysis was performed to examine the correlation between METTL14 and miR-335-5p, as well as the correlation between METTL14 and ITGβ4, while RNA immunoprecipitation (RIP) was used to determine the m6A modification level of ITGβ4. Additionally, molecular biology techniques were employed to evaluate the expression of glycolysis-related factors. Definitively, an LPS-induced ALI model was established to investigate the effect of miR-335-5p on mice lung tissue.

RESULTS

miR-335-5p was found to be highly expressed in HucMSC-Exo. Transfection with miR-335-5p mimics resulted in increased glucose uptake. Pearson correlation analysis revealed a negative correlation between METTL14 and miR-335-5p, as well as between METTL14 and ITGβ4. The m6A level of ITGβ4 was elevated in ALI. Overexpression of METTL14 was found to reduce the expression of ITGβ4 and glucose levels, while overexpression of ITGβ4 reversed the effects of METTL14 overexpression. In vivo, results demonstrated that miR-335-5p could improve the extent of lung tissue lesions and reduce glycolytic levels.

CONCLUSION

This study revealed the mechanism by which miR-335-5p derived from HucMSC-Exo could alleviate LPS-induced ALI by regulating the m6A modification of ITGβ4, providing a new direction for the treatment of ALI.

Kaempferitrin alleviates LPS-induced septic acute lung injury in mice through downregulating NF-κB pathway

BACKGROUND

Acute lung injury (ALI) causes severe and uncontrolled pulmonary inflammation and has high morbidity in dying patients.

OBJECTIVE

This study aimed to evaluate the potential function of Kaempferitrin (Kae) and uncover its mechanisms in ALI.

MATERIAL AND METHODS

We evaluated the role of Kae in ALI through the lipopolysaccharide (LPS)-induced histopathological changes, lung wet/dry (W/D) ratio, total bronchoalveolar lavage fluid (BALF) cells count, pulmonary inflammation, and the levels of interleukin (IL)-6, tumor necrosis factor-α (TNF-α), and IL-1β. The effect of Kae on NF-κB signaling pathway was discovered through the protein expression levels of transcription factors p65, p-p65, IκBα, and p-IκBα by Western blot analysis.

RESULTS

The results showed that Kae could improve lung injury by reducing apoptosis, histopathological changes, and lung W/D ratio; more importantly, Kae enhanced the survival of ALI mice. Moreover, Kae relieved inflammation, as it reduced total BALF cells count, and deceased the levels of TNF-α, IL-6, and IL-1β in serum. In addition, Western blot analysis data suggested that Kae could decrease the protein expression levels of transcription factors p65, p-p65, IκB-α, and p-IκB-α, which were promoted by LPS.

CONCLUSION

The results of this study suggested that Kae could relieve LPS-induced ALI in mice and reduce inflammation and apoptosis through NF-κB pathway.

LncRNA 220: A Novel Long Non-Coding RNA Regulates Autophagy and Apoptosis in Kupffer Cells via the miR-5101/PI3K/AKT/mTOR Axis in LPS-Induced Endotoxemic Liver Injury in Mice

Sepsis is a severe medical condition distinguished by immune systematic dysfunction and multiple organic injury, or even failure, resulting from an acute systemic inflammatory response. Acute liver injury (ALI) could be considered as a notable inflammatory outcome of sepsis. Studies have demonstrated the essential roles played by long non-coding RNAs (lncRNAs) in mediating the processes of various diseases, including their ability to engage in interactions with microRNAs (miRNAs) as complexes of competing endogenous RNA (ceRNA) to modulate signaling pathways. In this study, a newly discovered lncRNA, named 220, was identified to function in regulating autophagy and apoptosis in Kupffer cells treated with lipopolysaccharide (LPS). This was achieved through sponging miR-5101 as a ceRNA complex, as identified via high-throughput sequencing. The expression of 220 was found to be significantly different in the hepatic tissues of endotoxemic mice that were treated with LPS for 8 h, ultimately modulating the ALI process. Our studies have collectively demonstrated that 220 is a novel regulator that acts on LPS-induced autophagy and apoptosis in Kupffer cells, thereby mediating the ALI process induced by LPS. Furthermore, the validation of our findings using clinical databases suggests that 220 could potentially serve as a molecular target of clinical, diagnostic, and therapeutic significance in septic liver injury.

Epigallocatechin-3-Gallate Attenuates Leukocyte Infiltration in 67-kDa Laminin Receptor-Dependent and -Independent Pathways in the Rat Frontoparietal Cortex following Status Epilepticus

Status epilepticus (SE) evokes leukocyte infiltration in the frontoparietal cortex (FPC) without the blood-brain barrier disruption. Monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2) regulate leukocyte recruitments into the brain parenchyma. Epigallocatechin-3-gallate (EGCG) is an antioxidant and a ligand for non-integrin 67-kDa laminin receptor (67LR). However, it is unknown whether EGCG and/or 67LR affect SE-induced leukocyte infiltrations in the FPC. In the present study, SE infiltrated myeloperoxidase (MPO)-positive neutrophils, as well as cluster of differentiation 68 (CD68)-positive monocytes in the FPC are investigated. Following SE, MCP-1 was upregulated in microglia, which was abrogated by EGCG treatment. The C-C motif chemokine receptor 2 (CCR2, MCP-1 receptor) and MIP-2 expressions were increased in astrocytes, which were attenuated by MCP-1 neutralization and EGCG treatment. SE reduced 67LR expression in astrocytes, but not endothelial cells. Under physiological conditions, 67LR neutralization did not lead to MCP-1 induction in microglia. However, it induced MIP-2 expression and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in astrocytes and leukocyte infiltration in the FPC. Co-treatment of EGCG or U0126 (an ERK1/2 inhibitor) attenuated these events induced by 67LR neutralization. These findings indicate that the EGCG may ameliorate leukocyte infiltration in the FPC by inhibiting microglial MCP-1 induction independent of 67LR, as well as 67LR-ERK1/2-MIP-2 signaling pathway in astrocytes.

Promising natural products against SARS-CoV-2: Structure, function, and clinical trials

The corona virus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus type 2 (SARS-COV-2) poses a severe threat to human health and still spreads globally. Due to the high mutation ratio and breakthrough infection rate of the virus, vaccines and anti-COVID-19 drugs require continual improvements. Drug screening research has shown that some natural active products can target the critical proteins of SARS-CoV-2, including 3CLpro, ACE2, FURIN, and RdRp, which could produce great inhibitory effects on SARS-COV-2. In addition, some natural products have displayed activities of immunomodulation, antiinflammatory, and antihepatic failure in COVID-19 clinical trials, which may relate to their non-monomeric structures. However, further evaluation and high-quality assessments, including safety verification tests, drug interaction tests, and clinical trials, are needed to substantiate natural products' multi-target and multi-pathway effects on COVID-19. Here, we review the literature on several promising active natural products that may act as vaccine immune enhancers or provide targeted anti-COVID-19 drugs. The structures, mechanisms of action, and research progress of these natural products are analyzed, to hopefully provide effective ideas for the development of targeted drugs that possess better structure, potency, and safety.

Natural therapeutics and nutraceuticals for lung diseases: Traditional significance, phytochemistry, and pharmacology

BACKGROUND

Lung diseases including chronic obstructive pulmonary disease (COPD), infections like influenza, acute respiratory distress syndrome (ARDS), asthma and pneumonia lung cancer (LC) are common causes of sickness and death worldwide due to their remoteness, cold and harsh climatic conditions, and inaccessible health care facilities.

PURPOSE

Many drugs have already been proposed for the treatment of lung diseases. Few of them are in clinical trials and have the potential to cure infectious diseases. Plant extracts or herbal products have been extensively used as Traditional Chinese Medicine (TCM) and Indian Ayurveda. Moreover, it has been involved in the inhibition of certain genes/protiens effects to promote regulation of signaling pathways. Natural remedies have been scientifically proven with remarkable bioactivities and are considered a cheap and safe source for lung disease.

METHODS

This comprehensive review highlighted the literature about traditional plants and their metabolites with their applications for the treatment of lung diseases through experimental models in humans. Natural drugs information and mode of mechanism have been studied through the literature retrieved by Google Scholar, ScienceDirect, SciFinder, Scopus and Medline PubMed resources against lung diseases.

RESULTS

In vitro, in vivo and computational studies have been explained for natural metabolites derived from plants (like flavonoids, alkaloids, and terpenoids) against different types of lung diseases. Probiotics have also been biologically active therapeutics against cancer, anti-inflammation, antiplatelet, antiviral, and antioxidants associated with lung diseases.

CONCLUSION

The results of the mentioned natural metabolites repurposed for different lung diseases especially for SARS-CoV-2 should be evaluated more by advance computational applications, experimental models in the biological system, also need to be validated by clinical trials so that we may be able to retrieve potential drugs for most challenging lung diseases especially SARS-CoV-2.

Obacunone alleviates ferroptosis during lipopolysaccharide-induced acute lung injury by upregulating Nrf2-dependent antioxidant responses

BACKGROUND

Acute lung injury (ALI) has received considerable attention in the field of intensive care as it is associated with a high mortality rate. Obacunone (OB), widely found in citrus fruits, is a natural bioactive compound with anti-inflammatory and antioxidant activities. However, it is not clear whether OB protects against lipopolysaccharide (LPS)-induced ALI. Therefore, in this study, we aimed to evaluate the protective effects of OB and the potential mechanisms against LPS-induced ALI and BEAS-2B cell injury.

METHODS

We established a model of BEAS-2B cell injury and a mouse model of ALI by treating with LPS. Samples of in vitro model were subjected to cell death, Cell Counting Kit-8, and lactate dehydrogenase (LDH) release assays. The total number of cells and neutrophils, protein content, and levels of IL-6, TNF-α, and IL-1β were determined in bronchoalveolar lavage fluid (BALF). Glutathione, reactive oxygen species, and malondialdehyde levels were determined in lung tissue. Additionally, immunohistochemical analysis, immunofluorescence, western blot, quantitative real-time PCR, and enzyme-linked immunosorbent assay were conducted to examine the effects of OB. Furthermore, mice were treated with an Nrf2 inhibitor (ML385) to verify its role in ferroptosis. Data were analyzed using one-way analysis of variance or paired t-tests.

RESULTS

Compared with the LPS group, OB effectively alleviated LPS-induced ALI by decreasing lung wet/dry weight ratio, reactive oxygen species and malondialdehyde production, and superoxide dismutase and glutathione consumption in vivo. In addition, OB significantly alleviated lung histopathological injury, reduced inflammatory cytokine secretion and Fe²⁺ and 4-HNE levels, and upregulated GPX4, SLC7A11, and Nrf2 expression. Mechanistically, OB activated Nrf2 by inhibiting Nrf2 ubiquitinated proteasome degradation. ML385 reversed the protective effects of OB against LPS-induced ALI.

CONCLUSION

Overall, OB alleviates LPS-induced ALI, making it a potential novel protective agent against LPS-induced ALI.

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-1β and IL-6 gene expression induced by LPS. In vivo, both compounds reduced lung edema, inflammatory cells, and the IL-6 and IL-1 β 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.

EGCG promotes PRKCA expression to alleviate LPS-induced acute lung injury and inflammatory response

Acute lung injury (ALI), which could be induced by multiple factors such as lipopolysaccharide (LPS), refer to clinical symptoms of acute respiratory failure, commonly with high morbidity and mortality. Reportedly, active ingredients from green tea have anti-inflammatory and anticancer properties, including epigallocatechin-3-gallate (EGCG). In the present study, protein kinase C alpha (PRKCA) is involved in EGCG protection against LPS-induced inflammation and ALI. EGCG treatment attenuated LPS-stimulated ALI in mice as manifested as improved lung injury scores, decreased total cell amounts, neutrophil amounts and macrophage amounts, inhibited the activity of MPO, decreased wet-to-dry weight ratio of lung tissues, and inhibited release of inflammatory cytokines TNF-α, IL-1β, and IL-6. PRKCA mRNA and protein expression showed to be dramatically decreased by LPS treatment while reversed by EGCG treatment. Within LPS-stimulated ALI mice, PRKCA silencing further aggravated, while PRKCA overexpression attenuated LPS-stimulated inflammation and ALI through MAPK signaling pathway. PRKCA silencing attenuated EGCG protection. Within LPS-induced RAW 264.7 macrophages, EGCG could induce PRKCA expression. Single EGCG treatment or Lv-PRKCA infection attenuated LPS-induced increases in inflammatory factors; PRKCA silencing could reverse the suppressive effects of EGCG upon LPS-stimulated inflammatory factor release. In conclusion, EGCG pretreatment inhibits LPS-induced ALI in mice. The protective mechanism might be associated with the inhibitory effects of PRKCA on proinflammatory cytokine release via macrophages and MAPK signaling pathway.

Potential protective mechanisms of green tea polyphenol EGCG against COVID-19

Background

The world is in the midst of the COVID-19 pandemic. In this comprehensive review, we discuss the potential protective effects of (−)-epigallocatechin-3-gallate (EGCG), a major constituent of green tea, against COVID-19.

Scope and approach

Information from literature of clinical symptoms and molecular pathology of COVID-19 as well as relevant publications in which EGCG shows potential protective activities against COVID-19 is integrated and evaluated.

Key findings and conclusions

EGCG, via activating Nrf2, can suppress ACE2 (a cellular receptor for SARS-CoV-2) and TMPRSS2, which mediate cell entry of the virus. Through inhibition of SARS-CoV-2 main protease, EGCG may inhibit viral reproduction. EGCG via its broad antioxidant activity may protect against SARS-CoV-2 evoked mitochondrial ROS (which promote SARS-CoV-2 replication) and against ROS burst inflicted by neutrophil extracellular traps. By suppressing ER-resident GRP78 activity and expression, EGCG can potentially inhibit SARS-CoV-2 life cycle. EGCG also shows protective effects against 1) cytokine storm-associated acute lung injury/acute respiratory distress syndrome, 2) thrombosis via suppressing tissue factors and activating platelets, 3) sepsis by inactivating redox-sensitive HMGB1, and 4) lung fibrosis through augmenting Nrf2 and suppressing NF-κB. These activities remain to be further substantiated in animals and humans. The possible concerted actions of EGCG suggest the importance of further studies on the prevention and treatment of COVID-19 in humans. These results also call for epidemiological studies on potential preventive effects of green tea drinking on COVID-19.

Panaxydol attenuates ferroptosis against LPS-induced acute lung injury in mice by Keap1-Nrf2/HO-1 pathway

Background

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) induces uncontrolled and self-amplified pulmonary inflammation, and has high morbidity and mortality rates in critically ill patients. In recent years, many bioactive ingredients extracted from herbs have been reported to effectively ameliorate ALI/ARDS via different mechanisms. Ferroptosis, categorized as regulated necrosis, is more immunogenic than apoptosis and contributes to the progression of ALI. In this study, we examined the impact of panaxydol (PX), isolated from the roots of Panax ginseng, on lipopolysaccharide (LPS)-induced ALI in mice.

Methods

In vivo, the role of PX on LPS-induced ALI in mice was tested by determination of LPS-induced pulmonary inflammation, pulmonary edema and ferroptosis. In vitro, BEAS-2B cells were used to investigate the molecular mechanisms by which PX functions via determination of inflammation, ferroptosis and their relationship.

Results

Administration of PX protected mice against LPS-induced ALI, including significantly ameliorated lung pathological changes, and decreased the extent of lung edema, inflammation, and ferroptosis. In vitro, PX inhibited LPS-induced ferroptosis and inflammation in bronchial epithelial cell line BEAS-2B cells. The relationship between ferroptosis and inflammation was investigated. The results showed that ferroptosis mediated inflammation in LPS-treated BEAS-2B cells, and PX might ameliorate LPS-induced inflammation via inhibiting ferroptosis. Meanwhile, PX could upregulate Keap1-Nrf2/HO-1 pathway, and selective inhibition of Keap1-Nrf2/HO-1 pathway significantly abolished the anti-ferroptotic and anti-inflammatory functions of PX in LPS-treated cells.

Conclusion

PX attenuates ferroptosis against LPS-induced ALI via Keap1-Nrf2/HO-1 pathway, and is a promising novel therapeutic candidate for ALI.

The Anti-Inflammatory Role of Bilirubin on "Two-Hit" Sepsis Animal Model

Introduction: Bilirubin is a product of the heme catabolism pathway, and it is excreted in bile and removed from the body through the urine. Bilirubin has potent antioxidant properties but also plays a role in anti-inflammation by protecting the body against endotoxin-induced lung inflammation, down-regulating the expression of adhesion molecules, and inhibiting the infiltration of inflammatory cells. Thus, bilirubin is a promising agent that could use in inflammation disease treatment. The application of bilirubin on the “two-hit” sepsis animal model has been, to date, unknown. Methods: we used lipopolysaccharide to induce initial insults in C57BL/6 mice. After 24 h, mice underwent cecal ligation and puncture to induce the “two-hit” sepsis model. Next, mice were administered 30 mg/kg bilirubin and we observed an improvement. Results: We observed that bilirubin inhibited the expression of pro-inflammatory cytokines, while the levels of anti-inflammatory cytokines were significantly augmented in the lung. Bilirubin improved the survival rate in the sepsis model. Furthermore, we suggest that bilirubin can modulate the accumulation of T-regulatory cells and myeloid-derived suppressor cells. Notably, bilirubin suppressed the activation and functions of T-cells. Conclusions: These results clarified that bilirubin might improve tissue injury in sepsis through anti-inflammatory mechanisms.

Natural polyphenols for the prevention of irritable bowel syndrome: molecular mechanisms and targets; a comprehensive review

Irritable bowel syndrome (IBS) is a well diagnosed disease, thoroughly attributed to series of symptoms criteria that embrace a broad range of abdominal complainers. Such criteria help to diagnosis the disease and can guide controlled clinical trials to seek new therapeutic agents. Accordingly, a verity of mechanisms and pathophysiological conditions including inflammation, oxidative stress, lipid peroxidation and different life styles are involved in IBS. Predictably, diverse therapeutic approaches are available and prescribed by clinicians due to major manifestations (i.e., diarrhea-predominance, constipation-predominance, abdominal pain and visceral hypersensitivity), psychological disturbances, and patient preferences between herbal treatments versus pharmacological therapies, dietary or microbiological approaches. Herein, we gathered the latest scientific data between 1973 and 2019 from databases such as PubMed, Google Scholar, Scopus and Cochrane library on relevant studies concerning beneficial effects of herbal treatments for IBS, in particular polyphenols. This is concluded that polyphenols might be applicable for preventing IBS and improving the IBS symptoms, mainly through suppressing the inflammatory signaling pathways, which nowadays are known as novel platform for the IBS management. Graphical abstract.

Epigallocatechin-3-gallate downregulates lipopolysaccharide signaling in human aortic endothelial cells by inducing ectodomain shedding of TLR4

Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea leaves, has anti-inflammatory effects. In this study, we investigated the mechanism by which EGCG attenuates the effects of lipopolysaccharide (LPS), an agonist of toll-like receptor 4 (TLR4), in cultured human aortic endothelial cells (HAECs). The increase in the expression of intercellular adhesion molecule-1 (ICAM-1) induced by LPS (100 ng/ml) was effectively attenuated by pretreatment with EGCG (50 μM). Importantly, EGCG treatment resulted in a rapid reduction of cellular TLR4, which was accompanied by an increase in the N-terminal fragment of TLR4 in the culture supernatant, indicating that EGCG induces ectodomain shedding of TLR4. EGCG increased cytosolic Ca²⁺ by inducing the release of intracellular stored Ca²⁺ and the influx of extracellular Ca²⁺; accordingly, EGCG-induced ectodomain shedding of TLR4 was nullified by pretreatment with BAPTA-AM (10 μM), an intracellular Ca²⁺ chelator. EGCG induced translocation of a disintegrin and metalloprotease 10 (ADAM10) to the cell surface, which was also blocked by BAPTA-AM. Treatment with ADAM10 inhibitor (GI254023X, 2 μM) and siRNA-mediated depletion of ADAM10 prevented EGCG-induced ectodomain shedding of TLR4 and abolished the inhibitory effect of EGCG on LPS-induced ICAM-1 expression. Collectively, these findings suggest that EGCG decreases cell surface TLR4 in HAECs by inducing ADAM10-mediated ectodomain shedding, and thereby attenuates the effects of LPS. This is a new mechanism of the suppressive effect of EGCG on LPS signaling.

Potent Inhibitory Effects of Quercetin on Inflammatory Responses of Collagen-Induced Arthritis in Mice

BACKGROUND

Production of tumor necrosis factor (TNF)-α by inflammatory cells in lesions is the hallmark of the pathogenesis of rheumatoid arthritis (RA). Regulation of inflammatory responses in knee joints of patients with RA is critical for improving severe symptoms. Flavonoids have inhibitory effects on the acute and chronic inflammatory responses caused by TNF-α. The flavonoid quercetin (QUER) is one of the most prominent dietary antioxidants.

OBJECTIVE

The present study investigated the preventive and therapeutic effects of QUER on inflammatory responses in collagen-induced arthritis (CIA) in mice.

METHODS

Mice with CIA, a mouse model for RA, were treated with QUER orally three times a week either from the second immunization with collagen (day 21) or day 28 when symptoms of CIA had developed midway.

RESULTS

In both cases, inflammation-related clinical scores of knee joints were significantly reduced by treatment with QUER. Histological analyses showed that the representative characteristics of RA, such as damage to interchondral joints, infiltration of inflammatory cells, and pannus formation, were significantly reduced by QUER treatment. Oral administration of QUER significantly decreases lipopolysaccharide (LPS)-induced TNF-α production in a dose-dependent manner. Expression of TNF- α mRNA in knee joints was decreased in QUER-treated mice, compared with those of CIA controls.

CONCLUSION

These results suggest that oral administration of QUER might effectively improve symptoms of RA.

Epigallocatechin-3-gallate ameliorates lipopolysaccharide-induced acute lung injury by suppression of TLR4/NF-κB signaling activation

Acute lung injury (ALI) is a serious clinical syndrome with a high rate of mortality. The activation of inflammation is well-recognized as a vital factor in the pathogenesis of lipopolysaccharide (LPS)-induced ALI. Therefore, suppression of the inflammatory response could be an ideal strategy to prevent ALI. Epigallocatechin-3-gallate (EGCG), mainly from green tea, has been shown to have an anti-inflammatory effect. The aim of the study was to explore whether EGCG alleviates inflammation in sepsis-related ALI. Male BALB/C mice were treated with EGCG (10 mg/kg) intraperitoneally (ip) 1 h before LPS injection (10 mg/kg, ip). The results showed that EGCG attenuated LPS-induced ALI as it decreased the changes in blood gases and reduced the histological lesions, wet-to-dry weight ratios, and myeloperoxidase (MPO) activity. In addition, EGCG significantly decreased the expression of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in the lung, serum, and bronchoalveolar lavage fluid, and alleviated the expression of TLR-4, MyD88, TRIF, and p-p65 in the lung tissue. In addition, it increased the expression of IκB-α and had no influence on the expression of p65. Collectively, these results demonstrated the protective effects of EGCG against LPS-induced ALI in mice through its anti-inflammatory effect that may be attributed to the suppression of the activation of TLR 4-dependent NF-κB signaling pathways.

Epigallocatechin gallate attenuates mitochondrial DNA-induced inflammatory damage in the development of ventilator-induced lung injury

OBJECTIVE

We aim to investigate the role of mitochondrial DNA (mtDNA), a novel endogenous pro-inflammatory cytokine, in the development of ventilator-induced lung injury (VILI). Moreover, the protective effect of epigallocatechin gallate (EGCG) on VILI through inhibiting local mtDNA release was examined.

METHODS

From March 2015 to March 2016, bronchoalveolar lavage fluid (BALF) from 36 patients with VILI and well-matched 36 patients without VILI after major surgery were consecutively collected. The expression levels of mtDNA and inflammatory cytokines in BALF were tested. SD rats were divided into five groups: control, low tidal volume (7 ml/kg) group, high tidal volume (HTV, 40 ml/kg) group, HTV+low dose EGCG and HTV+high dose EGCG groups. BALF were collected to examine the expression levels of mtDNA and several inflammatory cytokines and the lung tissue was harvested for pathological examinations. In addition, cyclic stretch cell culture was used and culture media was collected to analyze expressions of inflammatory cytokines. Administration of mtDNA in a rat model and in vitro cell culturing were used to confirm its pro-inflammatory properties in the development of inflammatory lung injury.

RESULTS

A Significant elevation of mtDNA was detected in BALF from patients with VILI (581 ± 193 vs. 311 ± 137, p < 0.05) and also in rats ventilated with HTV. EGCG could significantly inhibit HTV-induced local mtDNA release and attenuate the level of inflammatory lung injuries (reduced infiltration of local inflammatory cells, lower lung wet/dry ratio and expression levels of inflammatory cytokines). The beneficial effects of EGCG on preventing inflammatory lung injuries were in a concentration-dependent manner. Meanwhile, higher expression levels of mtDNA and inflammatory cytokines were observed in the media of cyclic stretched cell culture compared to those in the control group (p < 0.05). Furthermore, intra-tracheal administration of mtDNA in rats could lead to a marked increase of local inflammatory cytokines and subsequent inflammatory lung injuries (p < 0.05). And by adding mtDNA into the cell culture, higher level of inflammatory cytokines in the media was detected (p < 0.05). EGCG also showed preventive effects on inflammatory responses on a concentration-dependent manner (p < 0.05).

CONCLUSION

The increased expression level of mtDNA and subsequent inflammatory cytokines overproduction may play an important role in the development of VILI. EGCG may be a potential novel therapeutic candidate for protection against VILI by inhibiting the local release of mtDNA.

Treatments for Pulmonary Ricin Intoxication: Current Aspects and Future Prospects

Ricin, a plant-derived toxin originating from the seeds of Ricinus communis (castor beans), is one of the most lethal toxins known, particularly if inhaled. Ricin is considered a potential biological threat agent due to its high availability and ease of production. The clinical manifestation of pulmonary ricin intoxication in animal models is closely related to acute respiratory distress syndrome (ARDS), which involves pulmonary proinflammatory cytokine upregulation, massive neutrophil infiltration and severe edema. Currently, the only post-exposure measure that is effective against pulmonary ricinosis at clinically relevant time-points following intoxication in pre-clinical studies is passive immunization with anti-ricin neutralizing antibodies. The efficacy of this antitoxin treatment depends on antibody affinity and the time of treatment initiation within a limited therapeutic time window. Small-molecule compounds that interfere directly with the toxin or inhibit its intracellular trafficking may also be beneficial against ricinosis. Another approach relies on the co-administration of antitoxin antibodies with immunomodulatory drugs, thereby neutralizing the toxin while attenuating lung injury. Immunomodulators and other pharmacological-based treatment options should be tailored according to the particular pathogenesis pathways of pulmonary ricinosis. This review focuses on the current treatment options for pulmonary ricin intoxication using anti-ricin antibodies, disease-modifying countermeasures, anti-ricin small molecules and their various combinations.

Quercetin suppresses NLRP3 inflammasome activation in epithelial cells triggered by Escherichia coli O157:H7

Inflammatory responses elicited by LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is induced by a wide variety of stress signals including infectious agents and cellular disorders. E. coli O157:H7 causes serious gastrointestinal diseases that results in severe inflammation and oxidative stress, causing host cell damage. In this study, we found that E. coli O157:H7 infection induced NLRP3 assembly, caspase-1 activation and interleukin (IL)-1β and IL-18 release in Caco-2 cells. Infection also resulted in mitochondrial dysfunction with disrupted mitochondrial potential and mitochondrial complex-I activity, as well as the cytosolic release of cytochrome c and altered mitochondrial respiratory chain. The damage of mitochondria led to increased production of reactive oxygen species (ROS) and cytosolic release of mitochondrial DNA. Moreover, ROS was required for E. coli O157:H7 induced NLRP3 assembly as inhibiting mitochondrial ROS release by ROS scavengers Mito-TEMPO and N-acetylcysteine abrogated NLRP3 inflammasome activation in Caco-2 cells in response to E. coli O157:H7. Quercetin, one of the most important flavonoids in plant origin foods, had a protective role in inhibiting NLRP3 activation upon E. coli O157:H7 infection by protecting mitochondrial integrity and inhibiting mitochondrial ROS release. In addition, E. coli O157:H7 infection inhibited the host autophagy while quercetin treatment augmented autophagy activation, which further blocked ROS generation and IL-1β and IL-18 release. In summary, E. coli O157:H7 infection induced mitochondrial ROS release and NLRP3 assembly in host cells, while quercetin exerted a preventive role in host cells upon E. coli O157:H7 infection partially due to prevention of ROS production and activation of autophagy.

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-1β 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.

Epigallocatechin-3-gallate suppresses alveolar epithelial cell apoptosis in seawater aspiration-induced acute lung injury via inhibiting STAT1-caspase-3/p21 associated pathway

The apoptosis of alveolar epithelial cells is important in seawater aspiration‑induced acute lung injury (ALI). The present study aimed to investigate whether epigallocatechin-3-gallate (EGCG) is able to suppress apoptosis in alveolar epithelial cells in seawater aspiration‑induced ALI in vivo and in vitro, and the possible mechanisms underlying it. The results indicated that seawater aspiration‑induced ALI in rats is accompanied by increased apoptosis in lung tissue cells and the expression of apoptosis‑associated proteins, caspase‑3 and p21. EGCG pretreatment significantly ameliorated seawater aspiration‑induced ALI. Furthermore, EGCG decreased seawater aspiration‑induced apoptosis and the expression of caspase‑3 and p21 in lung tissue cells. Seawater‑challenged A549 cells experienced increased apoptosis and elevated levels of phosphorylated‑signal transducer and activator of transcription 1 (P‑STAT1). EGCG pretreatment of the cells resulted in significantly decreased seawater‑induced apoptosis and lower levels of STAT1 and P‑STAT1 in A549 cells. This suggests that EGCG suppresses alveolar epithelial cell apoptosis in seawater aspiration‑induced ALI via inhibiting the STAT1-caspase-3/p21 associated pathway.

Epigallocatechin gallate attenuates cardiopulmonary bypass-associated lung injury

BACKGROUND

Lung dysfunction constitutes a severe complication after major cardiac surgery with cardiopulmonary bypass (CPB), substantially contributing to postoperative morbidity and mortality. The current possibilities of preventive and therapeutic interventions, however, remain insufficient. We, therefore, investigated the effects of intraoperative application of the antioxidant and anti-inflammatory green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) on CPB-associated lung injury.

MATERIALS AND METHODS

Thirty piglets (8-15 kg) were divided into four groups: sham-operated and saline-treated control group (n = 7); sham-operated and EGCG-treated control group (EGCG-control group; n = 7); CPB group (n = 10); and CPB + EGCG group (n = 6). The CPB groups underwent 120 min of CPB followed by 90 min of recovery time. In the CPB + EGCG group, EGCG (10 mg/kg body weight) was administered intravenously before and after CPB. Hemodynamic monitoring, blood gas analysis, hematoxylin-eosin staining, and immunohistochemistry of lung tissue were performed.

RESULTS

Histologic examination revealed thickening of the alveolar wall and enhanced alveolar neutrophil infiltration in the CPB group (P < 0.05) compared with those in the control group, which was prevented by EGCG (P < 0.05). In the CPB group, higher formation of poly(ADP-ribose) and nuclear translocation of apoptosis-inducing factor was detected in comparison with those in the control group (P < 0.001), which were both reduced in the CPB + EGCG group (P < 0.001). Compared with the control group, the EGCG-control group showed thickening of the alveolar wall and increased neutrophil infiltration (P < 0.05).

CONCLUSIONS

CPB leads to lung edema, pulmonary neutrophil infiltration, and presumably initiation of poly(ADP-ribose) polymerase-dependent cell death signaling in the lung. EGCG appears to attenuate CPB-associated lung injury, suggesting that this may provide a novel pharmacologic approach.

The green tea extract epigallocatechin-3-gallate inhibits irradiation-induced pulmonary fibrosis in adult rats

The present study evaluated the effect of epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, on irradiation-induced pulmonary fibrosis and elucidated its mechanism of action. A rat model of irradiation-induced pulmonary fibrosis was generated using a ⁶⁰Co irradiator and a dose of 22 Gy. Rats were intraperitoneally injected with EGCG (25 mg/kg) or dexamethasone (DEX; 5 mg/kg) daily for 30 days. Mortality rates and lung index values were calculated. The severity of fibrosis was evaluated by assaying the hydroxyproline (Hyp) contents of pulmonary and lung tissue sections post-irradiation. Alveolitis and fibrosis scores were obtained from semi-quantitative analyses of hematoxylin and eosin (H&E) and Masson’s trichrome lung section staining, respectively. The serum levels of transforming growth factor β1 (TGF-β1), interleukin (IL)-6, IL-10, and tumor necrosis factor-α (TNF-α) were also measured. Surfactant protein-B (SPB) and α-SMA expression patterns were evaluated using immunohistochemistry, and the protein levels of nuclear transcription factor NF-E2-related factor 2 (Nrf-2) and its associated antioxidant enzymes heme oxygenase-1 enzyme (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO-1) were examined via western blot analysis. Treatment with EGCG, but not DEX, reduced mortality rates and lung index scores, improved histological changes in the lung, reduced collagen depositions, reduced MDA content, enhanced SOD activity, inhibited (myo)fibroblast proliferation, protected alveolar epithelial type II (AE2) cells, and regulated serum levels of TGF-β1, IL-6, IL-10, and TNF-α. Treatment with EGCG, but not DEX, activated Nrf-2 and its downstream antioxidant enzymes HO-1 and NQO-1. Taken together, these results showed that EGCG treatment significantly inhibits irradiation-induced pulmonary fibrosis. Furthermore, the results suggested promising clinical EGCG therapies to treat this disorder.

Epigallocatechin-3-gallate ameliorates seawater aspiration-induced acute lung injury via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats

Signal transducers and activators of transcriptions 1 (STAT1) play an important role in the inflammation process of acute lung injury (ALI). Epigallocatechin-3-gallate (EGCG) exhibits a specific and strong anti-STAT1 activity. Therefore, our study is to explore whether EGCG pretreatment can ameliorate seawater aspiration-induced ALI and its possible mechanisms. We detected the arterial partial pressure of oxygen, lung wet/dry weight ratios, protein content in bronchoalveolar lavage fluid, and the histopathologic and ultrastructure staining of the lung. The levels of IL-1, TNF-α, and IL-10 and the total and the phosphorylated protein level of STAT1, JAK1, and JAK2 were assessed in vitro and in vivo. The results showed that EGCG pretreatment significantly improved hypoxemia and histopathologic changes, alleviated pulmonary edema and lung vascular leak, reduced the production of TNF-α and IL-1, and increased the production of IL-10 in seawater aspiration-induced ALI rats. EGCG also prevented the seawater aspiration-induced increase of TNF-α and IL-1 and decrease of IL-10 in NR8383 cell line. Moreover, EGCG pretreatment reduced the total and the phosphorylated protein level of STAT1 in vivo and in vitro and reduced the phosphorylated protein level of JAK1 and JAK2. The present study demonstrates that EGCG ameliorates seawater aspiration-induced ALI via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats.

Potential effects of medicinal plants and secondary metabolites on acute lung injury

Acute lung injury (ALI) is a life-threatening syndrome that causes high morbidity and mortality worldwide. ALI is characterized by increased permeability of the alveolar-capillary membrane, edema, uncontrolled neutrophils migration to the lung, and diffuse alveolar damage, leading to acute hypoxemic respiratory failure. Although corticosteroids remain the mainstay of ALI treatment, they cause significant side effects. Agents of natural origin, such as medicinal plants and their secondary metabolites, mainly those with very few side effects, could be excellent alternatives for ALI treatment. Several studies, including our own, have demonstrated that plant extracts and/or secondary metabolites isolated from them reduce most ALI phenotypes in experimental animal models, including neutrophil recruitment to the lung, the production of pro-inflammatory cytokines and chemokines, edema, and vascular permeability. In this review, we summarized these studies and described the anti-inflammatory activity of various plant extracts, such as Ginkgo biloba and Punica granatum, and such secondary metabolites as epigallocatechin-3-gallate and ellagic acid. In addition, we highlight the medical potential of these extracts and plant-derived compounds for treating of ALI.

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

Previous studies have shown that sauchinone modulates the expression of inflammatory mediators through mitogen-activated protein kinase (MAPK) pathways in various cell types. However, little information exists about the effect of sauchinone on neutrophils, which play a crucial role in inflammatory process such as acute lung injury (ALI). We found that sauchinone decreased the phosphorylation of p38 MAPK in lipopolysaccharide (LPS)-stimulated murine bone marrow neutrophils, but not ERK1/2 and JNK. Exposure of LPS-stimulated neutrophils to sauchinone or SB203580, a p38 inhibitor, diminished production of tumor necrosis factor (TNF)-α and macrophage inflammatory protein (MIP)-2 compared to neutrophils cultured with LPS. Treatment with sauchinone decreased the level of phosphorylated ribosomal protein S6 (rpS6) in LPS-stimulated neutrophils. Systemic administration of sauchinone to mice led to reduced levels of phosphorylation of p38 and rpS6 in mice lungs given LPS, decreased TNF-α and MIP-2 production in bronchoalveolar lavage fluid, and also diminished the severity of LPS-induced lung injury, as determined by reduced neutrophil accumulation in the lungs, wet/dry weight ratio, and histological analysis. These results suggest that sauchinone diminishes LPS-induced neutrophil activation and ALI.

Effect of manassantin B, a lignan isolated from Saururus chinensis, on lipopolysaccharide-induced interleukin-1β in RAW 264.7 cells

BACKGROUND

Elevated systemic levels of pro-inflammatory cytokines cause hypotension during septic shock and induce capillary leakage in acute lung injury. Manassantin B has anti-inflammatory and anti-plasmoidal properties. This study examined the effects of manassantin B on lipopolysaccharide (LPS)-induced inflammatory response in murine macrophages.

METHODS

RAW 264.7 macrophage cells were incubated without or with (1, 3 and 10 µM) manassantin B and without or with (100 ng/ml) LPS. Manassantin B dissolved in phosphate buffered saline was added to the medium 1 h prior to the addition of LPS. The degree of activation of mitogen-activated protein kinase (MAPK) including extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun amino terminal kinases (JNK) and p38 MAPK, and the level of interleukin (IL)-1β were determined 30 min and 24 h after the addition of LPS respectively.

RESULTS

Manassantin B inhibited the production of IL-1β and attenuated the phosphorylations of ERK1/2 and p38 MAPK, but not that of JNK, in RAW 264.7 cells treated with LPS.

CONCLUSIONS

Manassantin B reduces LPS-induced IL-1β expression through effects on ERK1/2- and p38 MAPK-mediated pathways. Manassantin B has potential as a potent anti-inflammatory drug for use in pathological processes such as sepsis or acute lung injury.

Diabetes is an inflammatory disease: evidence from traditional Chinese medicines

Diabetes is usually associated with inflammation. Inflammation contributes to the development of diabetes. Traditional Chinese medicines (TCM) play an important role in lowering blood glucose and controlling inflammation. Many studies show that TCM with hypoglycaemic effects, for example Radix Astragali, Radix Rehmanniae, Radix Trichosanthis, Panax Ginseng, Fructus Schisandrae, Radix Ophiopogonis, Rhizoma Anemarrhenae, Radix Puerariae, Fructus Lycii, Poria, Rhizoma Coptidis, Rhizoma Dioscoreae, Rhizoma Polygonati, Radix Salviae Miltiorrhizae, Radix Glycyrrhizae, Semen Trigonellae, Momordica charantia, Allium sativum, Opuntia stricta, Aloe vera, Cortex Cinnamomi, Rhizoma Curcumae Longae, and so on, have nearly independent anti-inflammatory action. Antihyperglycaemic compounds, for example berberine, puerarin, quercetin, ferulic acid, astragaloside IV, curcumin, epigallocatechin gallate, resveratrol, tetrandrine, glycyrrhizin, emodin and baicalin, used in TCM also have anti-inflammatory effects. These studies suggest that TCM might exert hypoglycaemic effects that are partly mediated by the anti-inflammatory mechanisms. However, small amounts of TCM with potent anti-inflammatory action does not have any hypoglycaemic effect. This indirectly indicates that diabetes may be a low-grade inflammatory disease and potent regulation of inflammatory mediators may not be required. Studies of TCM add new evidences, which indicate that diabetes may be an inflammatory disease and slight or moderate inhibition of inflammation might be useful to prevent the development of diabetes. Through this review, we aim to develop more perspectives to indicate that diabetes may be an inflammatory disease and diverse TCM may share a common antidiabetic property: anti-inflammatory action. Further studies should focus on and validate inflammation-regulating targets of TCM that may be involved in inhibiting the development of diabetes.

Epigallocatechin-3-gallate (EGCG) attenuates inflammation in MRL/lpr mouse mesangial cells

Epigallocatechin-3-gallate (EGCG), a bioactive component of green tea, has been reported to exert anti-inflammatory effects on immune cells. EGCG is also shown to activate the metabolic regulator, adenosine 5'-monophosphate-activated protein kinase (AMPK). Reports have also indicated that EGCG inhibits the immune-stimulated phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway. The PI3K/Akt/mTOR pathway has been implicated in mesangial cell activation in lupus. Mesangial cells from MRL/lpr lupus-like mice are hyper-responsive to immune stimulation and overproduce nitric oxide (NO) and other inflammatory mediators when stimulated. In our current studies, we sought to determine the mechanism by which EGCG attenuates immune-induced expression of pro-inflammatory mediators. Cultured mesangial cells from MRL/lpr mice were pre-treated with various concentrations of EGCG and stimulated with lipopolysaccharide (LPS)/interferon (IFN)-gamma. EGCG activated AMPK and blocked LPS/IFN-gamma-induced inflammatory mediator production (iNOS expression, supernatant NO and interleukin-6). Interestingly, EGCG attenuated inflammation during AMPK inhibition indicating that the anti-inflammatory effect of EGCG may be partially independent of AMPK activation. Furthermore, we found that EGCG effectively inhibited the immune-stimulated PI3K/Akt/mTOR pathway independently of AMPK, by decreasing phosphorylation of Akt, suggesting an alternate mechanism for EGCG-mediated anti-inflammatory action in mesangial cells. Taken together, these studies show that EGCG attenuated inflammation in MRL/lpr mouse mesangial cells via the PI3K/Akt/mTOR pathway. Our findings suggest a potential therapeutic role for the use of EGCG to regulate inflammation and control autoimmune disease.