Cordycepin alleviates lipopolysaccharide-induced acute lung injury via Nrf2/HO-1 pathway

Decoction derived from Allium ascalonicum L. bulbs and Sojae Semen Praeparatum alleviates wind-cold-type common cold via Nrf2/HO-1 pathway and modulation of Lactobacillus murinus level

Background

Cong-Chi decoction (CCD) is made using Allium ascalonicum L. (shallot) bulbs and Sojae Semen Praeparatum (SSP). Shallot bulbs and SSP are both used regularly in traditional Chinese medicine; however, there are no recent pharmacological studies on their synergistic effects. Despite their roles in the treatment of the common cold for thousands of years, their pharmacological mechanisms of action against wind-cold-type common cold are yet to be explored comprehensively.

Methods

A mouse model was standardized using wind-cold modeling equipment to study the anti-inflammatory, antioxidant, and antiapoptotic effects of CCD. Then, 16S rRNA sequencing was employed to analyze the association between Lactobacillus murinus and changes in body temperature. Additionally, the antipyretic effects of L. murinus were validated via animal experiments.

Results

The results indicate that CCD improves the symptoms of wind-cold by reducing fever, levels of pro-inflammatory factors, and cellular apoptosis, as well as increasing the blood leukocyte and lymphocyte counts, thereby alleviating lung tissue damage. The effects of CCD are mediated by upregulation of pulmonary Nrf2 and HO-1 expressions, thereby reducing oxidative damage in the lungs, in addition to other anti-inflammatory mechanisms. Furthermore, CCD increases the abundance of L. murinus in the intestinal tract. The animal experiments confirm that L. murinus ameliorates fever in mice.

Conclusion

CCD exhibits remarkable antioxidant and anti-inflammatory properties for effectively treating wind-cold-type common cold. Furthermore, its regulatory effects on L. murinus represent a novel mechanism for product development.

Licochalcone B confers protective effects against LPS-Induced acute lung injury in cells and mice through the Keap1/Nrf2 pathway

BACKGROUND

Acute lung injury (ALI) is a severe and often fatal pulmonary disease. Current treatments for ALI and acute respiratory distress syndrome (ARDS) are limited. Natural product metabolites have shown promise as therapeutic alternatives. However, the effects of Licochalcone B (LCB) on ALI are largely unknown.

METHODS

We investigated the effects of LCB on lipopolysaccharide-challenged mice and human pulmonary microvascular endothelial cells. Cell viability, apoptosis, and ROS production were assessed. Lung tissue histopathology and oxidative stress and inflammation markers were evaluated. Protein expression levels were measured.

RESULTS

LCB had no cytotoxic effects on cells and increased cell viability. It reduced apoptosis and ROS levels in cells. In mice with ALI, LCB decreased lung tissue weight and improved oxidative stress and inflammation markers. It also enhanced expression levels of Nrf2, HO-1, and NQO1 while reducing Keap1.

CONCLUSION

LCB protects against LPS-induced acute lung injury in cells and mice. The Keap1/Nrf2 pathway may be involved in its protective effects. LCB shows potential as a strategy to alleviate ALI caused by LPS.

Fullerene C60 reduces acute lung injury by suppressing oxidative stress-mediated DMBA-induced apoptosis and autophagy by regulation of cytochrome-C/caspase-3/beclin-1/IL-1α/HO-1/p53 signaling pathways in rats

The objective of this study was to evaluate the effect of fullerene C60 nanoparticles against 7,12-dimethylbenz[a]anthracene (DMBA)-induced lung tissue damage in rats. 60 Wistar albino (8 weeks old) female rats were assigned into four groups: Control Group (C), Fullerene C60, DMBA, and Fullerene C60+DMBA. The rats in the DMBA and Fullerene C60+DMBA groups were administered DMBA (45 mg/kg bw, oral gavage). The rats in Fullerene C60, and Fullerene C60+DMBA groups were administered with Fullerene C60 (1.7 mg/kg bw, oral gavage). Expression levels of cytochrome-C, caspase-3, beclin-1, IL-1α, HO-1 and p53 proteins in lung tissue were determined by western blotting, lipid peroxidation malondialdehyde (MDA) analyzes, glutathione (GSH), glutathione peroxidase (GSH-Px), catalase activity (CAT) and total protein levels were determined by spectrophotometer. In addition, lung tissues were evaluated by histopathologically. Fullerene C60 reduced the increasing of MDA and IL-1α protein expression levels and attenuated histopathological changes in lung. Moreover, fullerene C60 enhanced the protein expression of cytochrome-C, caspase-3, beclin-1, HO-1, and p53, which were decreased in the DMBA group. Fullerene C60 has strong biological activity that it might be an effective approach for lung damage.

F. Alotaibi M, Nasrullah MZ, Alrabia MW, Asfour HZ, Abdel-Naim AB. Cordycepin- Melittin nanoconjugate intensifies wound healing efficacy in diabetic rats

The current study was designed to develop a nanoconjugate of cordycepin-melittin (COR-MEL) and assess its healing property in wounded diabetic rats. The prepared nanoconjugate has a particle size of 253.5 ± 17.4 nm with a polydispersity index (PDI) of 0.35 ± 0.04 and zeta potential of 17.2 ± 0.3 mV. To establish the wound healing property of the COR-MEL nanoconjugate, animal studies were pursued, where the animals with diabetes were exposed to excision and treated with COR hydrogel, MEL hydrogel, or COR-MEL nanoconjugate topically. The study demonstrated an accelerated wound contraction in COR-MEL nanoconjugate -treated diabetic rats, which was further validated by histological analysis. The nanoconjugate further exhibited antioxidant activities by inhibiting the accumulation of malondialdehyde (MDA) and exhaustion of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic activities. The nanoconjugate further demonstrated an enhanced anti-inflammatory activity by retarding the expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Additionally, the nanoconjugate exhibits a strong expression of transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF)-A, and platelet-derived growth factor (PDGFR)-β, indicating enrichment of proliferation. Likewise, nanoconjugate increased the concentration of hydroxyproline as well as the mRNA expression of collagen, type I, alpha 1 (Col 1A1). Thus, it is concluded that the nanoconjugate possesses a potent wound-healing activity in diabetic rats via antioxidant, anti-inflammatory, and pro-angiogenetic mechanisms.

Traditional Chinese medicine for treatment of sepsis and related multi-organ injury

Sepsis is a common but critical illness in patients admitted to the intensive care unit and is associated with high mortality. Although there are many treatments for sepsis, specific and effective therapies are still lacking. For over 2,000 years, traditional Chinese medicine (TCM) has played a vital role in the treatment of infectious diseases in Eastern countries. Both anecdotal and scientific evidence show that diverse TCM preparations alleviate organ dysfunction caused by sepsis by inhibiting the inflammatory response, reducing oxidative stress, boosting immunity, and maintaining cellular homeostasis. This review reports on the efficacy and mechanism of action of various TCM compounds, herbal monomer extracts, and acupuncture, on the treatment of sepsis and related multi-organ injury. We hope that this information would be helpful to better understand the theoretical basis and empirical support for TCM in the treatment of sepsis.

The protective effect of natural medicines against excessive inflammation and oxidative stress in acute lung injury by regulating the Nrf2 signaling pathway

Acute lung injury (ALI) is a common critical disease of the respiratory system that progresses into acute respiratory distress syndrome (ARDS), with high mortality, mainly related to pulmonary oxidative stress imbalance and severe inflammation. However, there are no clear and effective treatment strategies at present. Nuclear factor erythroid 2-related factor 2(Nrf2) is a transcription factor that interacts with multiple signaling pathways and regulates the activity of multiple oxidases (NOX, NOS, XO, CYP) related to inflammation and apoptosis, and exhibits antioxidant and anti-inflammatory roles in ALI. Recently, several studies have reported that the active ingredients of natural medicines show protective effects on ALI via the Nrf2 signaling pathway. In addition, they are cheap, naturally available, and possess minimal toxicity, thereby having good clinical research and application value. Herein, we summarized various studies on the protective effects of natural pharmaceutical components such as polyphenols, flavonoids, terpenoids, alkaloids, and polysaccharides on ALI through the Nrf2 signaling pathway and demonstrated existing gaps as well as future perspectives.

Lagerstroemia ovalifolia Exerts Anti- Inflammatory Effects in Mice of LPSInduced ALI via Downregulating of MAPK and NF-κB Activation

Lagerstroemia ovalifolia Teijsm. & Binn. (LO) (crape myrtle) has reportedly been used as traditional herbal medicine (THM) in Java, Indonesia. Our previous study revealed that the LO leaf extract (LOLE) exerted anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Based on this finding, the current study aimed to evaluate the protective effects of LOLE in a mouse model of LPS-induced acute lung injury (ALI). The results showed that treatment with LPS enhanced the inflammatory cell influx into the lungs and increased the number of macrophages and the secretion of the inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) of mice. However, these effects were notably abrogated with LOLE pretreatment. Furthermore, the increase of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and monocyte chemoattractant protein-1 (MCP-1) expression in the lung tissues of mice with ALI was also reversed by LOLE. In addition, LOLE significantly suppressed the LPS-induced activation of the MAPK/NF-κB signaling pathway and led to heme oxygenase-1 (HO-1) induction in the lungs. Additionally, in vitro experiments showed that LOLE enhanced the expression of HO-1 in RAW264.7 macrophages. The aforementioned findings collectively indicate that LOLE exerts an ameliorative effect on inflammatory response in the airway of ALI mice.

Modified Xiaoqinglong decoction alleviates lipopolysaccharide-induced acute lung injury in mice by regulating arachidonic acid metabolism and exerting anti-apoptotic and anti-inflammatory effects

Effective therapeutics are not available for acute lung injury (ALI) and acute respiratory distress syndrome. Modified Xiaoqinglong decoction (M-XQL) is reported to effectively treat pneumonia, but the underlying mechanisms are unclear. In this study, the therapeutic effect and mechanism of M-XQL were examined using a lipopolysaccharide (LPS)-induced ALI mouse model. The effects of M-XQL on lung injury, inflammatory responses, and cell apoptosis were analyzed. Additionally, high-throughput sequencing was performed to evaluate the therapeutic mechanism of M-XQL. Pretreatment with M-XQL significantly and dose-dependently mitigated the pathological changes and upregulation of pulmonary, nitric oxide content and cell apoptosis and serum tumor necrosis factor-alpha contents in the LPS-induced ALI mouse model. RNA sequencing analysis revealed that the expression of several arachidonic acid metabolism-associated genes in the LPS + high-dose M-XQL group differed from that in the LPS group. In particular, the Cbr2, Cyp4f18, and Cyp2e1 levels were upregulated, whereas the Alox12, Ptges, and Ptges2 levels were downregulated in the LPS + high-dose M-XQL group. These results suggest that M-XQL exerts therapeutic effects in ALI mice by regulating arachidonic acid metabolism and exerting anti-apoptotic and anti-inflammatory effects. Thus, M-XQL is a potential agent for the clinical treatment of ALI.

A Systematic Review of the Biological Effects of Cordycepin

We conducted a systematic review of the literature on the effects of cordycepin on cell survival and proliferation, inflammation, signal transduction and animal models. A total of 1204 publications on cordycepin were found by the cut-off date of 1 February 2021. After application of the exclusion criteria, 791 papers remained. These were read and data on the chosen subjects were extracted. We found 192 papers on the effects of cordycepin on cell survival and proliferation and calculated a median inhibitory concentration (IC50) of 135 µM. Cordycepin consistently repressed cell migration (26 papers) and cellular inflammation (53 papers). Evaluation of 76 papers on signal transduction indicated consistently reduced PI3K/mTOR/AKT and ERK signalling and activation of AMPK. In contrast, the effects of cordycepin on the p38 and Jun kinases were variable, as were the effects on cell cycle arrest (53 papers), suggesting these are cell-specific responses. The examination of 150 animal studies indicated that purified cordycepin has many potential therapeutic effects, including the reduction of tumour growth (37 papers), repression of pain and inflammation (9 papers), protecting brain function (11 papers), improvement of respiratory and cardiac conditions (8 and 19 papers) and amelioration of metabolic disorders (8 papers). Nearly all these data are consistent with cordycepin mediating its therapeutic effects through activating AMPK, inhibiting PI3K/mTOR/AKT and repressing the inflammatory response. We conclude that cordycepin has excellent potential as a lead for drug development, especially for age-related diseases. In addition, we discuss the remaining issues around the mechanism of action, toxicity and biodistribution of cordycepin.

An Update on the Role of Nrf2 in Respiratory Disease: Molecular Mechanisms and Therapeutic Approaches

Nuclear factor erythroid 2-related factor (Nrf2) is a transcriptional activator of the cell protection gene that binds to the antioxidant response element (ARE). Therefore, Nrf2 protects cells and tissues from oxidative stress. Normally, Kelch-like ECH-associated protein 1 (Keap1) inhibits the activation of Nrf2 by binding to Nrf2 and contributes to Nrf2 break down by ubiquitin proteasomes. In moderate oxidative stress, Keap1 is inhibited, allowing Nrf2 to be translocated to the nucleus, which acts as an antioxidant. However, under unusually severe oxidative stress, the Keap1-Nrf2 mechanism becomes disrupted and results in cell and tissue damage. Oxide-containing atmospheric environment generally contributes to the development of respiratory diseases, possibly leading to the failure of the Keap1-Nrf2 pathway. Until now, several studies have identified changes in Keap1-Nrf2 signaling in models of respiratory diseases, such as acute respiratory distress syndrome (ARDS)/acute lung injury (ALI), chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and asthma. These studies have confirmed that several Nrf2 activators can alleviate symptoms of respiratory diseases. Thus, this review describes how the expression of Keap1-Nrf2 functions in different respiratory diseases and explains the protective effects of reversing this expression.

Cordycepin Attenuates IFN-γ-Induced Macrophage IP-10 and Mig Expressions by Inhibiting STAT1 Activity in CFA-Induced Inflammation Mice Model

Cordycepin, a natural derivative of adenosine, has been shown to exert pharmacological properties including anti-oxidation, antitumor, and immune regulation. It is reported that cordycepin is involved in the regulation of macrophage function. However, the effect of cordycepin on inflammatory cell infiltration in inflammation remains ambiguous. In this study, we investigated the potential role of cordycepin playing in macrophage function in CFA-induced inflammation mice model. In this model, we found that cordycepin prevented against macrophage infiltration in paw tissue and reduced interferon-γ (IFN-γ) production in both serum and paw tissue. Using luciferase reporter assay, we found that cordycepin suppressed IFN-γ-induced activators of transcription-1 (STAT1) transcriptional activity in a dose-dependent manner. Moreover, western blotting data demonstrated that cordycepin inhibited IFN-γ-induced STAT1 activation through attenuating STAT1 phosphorylation. Further investigations revealed that cordycepin inhibited the expressions of IFN-γ-inducible protein 10 (IP-10) and monokine induced by IFN-γ (Mig), which were the effector genes in IFN-γ-induced STAT1 signaling. Meanwhile, the excessive inflammatory cell infiltration in paw tissue was reduced by cordycepin. These findings demonstrate that cordycepin alleviates excessive inflammatory cell infiltration through down-regulation of macrophage IP-10 and Mig expressions via suppressing STAT1 phosphorylation. Thus, cordycepin may be a potential therapeutic approach to prevent and treat inflammation-associated diseases.

Could natural products modulate early inflammatory responses, preventing acute respiratory distress syndrome in COVID-19-confirmed patients?

BACKGROUND

The ARDS (Acute Respiratory Distress Syndrome) is a severe respiratory syndrome that was recently associated as the main death cause in the COVID-19 pandemic outbreak. Hence, in order to prevent ARDS, the pulmonary function maintenance has been the target of several pharmacological approaches. However, there is a lack of reports regarding the use of effective pharmaceutical active natural products (PANPs) for early treatment and prevention of COVID-19-related ARDS. Therefore, the aim of this work was to conduct a systematic review regarding the PANPs that could be further studied as alternatives to prevent ARDS. Consequently, this work can pave the way to spread the use of PANPs on the prevention of ARDS in COVID-19-confirmed or -suspected patients.

METHODS

The search strategy included scientific studies published in English from 2015 to 2020 that promoted the elucidation of anti-inflammatory pathways targeting ARDS by in vitro and/or in vivo experiments using PANPs. Then, 74 studies regarding PANPs, able to maintain or improve the pulmonary function, were reported.

CONCLUSIONS

The PANPs may present different pulmonary anti-inflammatory pathways, wherein (i) reduction/attenuation of pro-inflammatory cytokines, (ii) increase of the anti-inflammatory mediators' levels, (iii) pulmonary edema inhibition and (iv) attenuation of lung injury were the most observed biological effects of such products in in vitro experiments or in clinical studies. Finally, this work highlighted the PANPs with promising potential to be used on respiratory syndromes, allowing their possible use as alternative treatment at the prevention of ARDS in COVID-19-infected or -suspected patients.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

The Anti-Inflammatory Effect of Trichilia martiana C. DC. in the Lipopolysaccharide-Stimulated Inflammatory Response in Macrophages and Airway Epithelial Cells and in LPS-Challenged Mice

A number of species of the genus Trichilia (Meliaceae) exhibit anti-inflammatory effects. However, the effect of Trichilia martiana C. DC. (TM) on lipopolysaccharide (LPS)-induced inflammation has not, to the best of our knowledge, yet been determined. Therefore, in the present study, the antiinflammatory effect of TM on LPS-stimulated RAW264.7 macrophages was evaluated. The ethanol extract of TM (TMEE) significantly inhibited LPS-induced nitric oxide (NO), prostaglandin 2 (PGE₂), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). TMEE also reduced the levels of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β and IL-6. The upregulation of mitogen-activated protein kinases (MAPKs) and NF-κB activation was revealed to be downregulated following TMEE pretreatment. Furthermore, TMEE was indicated to lead to the nucleus translocation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2) and the expression of heme oxygenase-1 (HO-1). In H292 airway epithelial cells, the pretreatment of TMEE significantly downregulated the production of LPS-stimulated IL-1β, and TMEE was indicated to increase the expression of HO-1. In animal models exhibiting LPS-induced acute lung injury (ALI), treatment with TMEE reduced the levels of macrophages influx and TNF-α production in the bronchoalveolar lavage fluid (BALF) of ALI mice. Additionally, TMEE significantly downregulated the activation of ERK, JNK and IκB, and upregulated the expression of HO-1 in the lungs of ALI mice. In conclusion, the results of the current study demonstrated that TMEE could exert a regulatory role in the prevention or treatment of the endotoxin-mediated inflammatory response.

Anti-inflammatory effects of cordycepin: A review

Cordycepin is the major bioactive component extracted from Cordyceps militaris. In recent years, cordycepin has received increasing attention owing to its multiple pharmacological activities. This study reviews recent researches on the anti-inflammatory effects and the related activities of cordycepin. The results from our review indicate that cordycepin exerts protective effects against inflammatory injury for many diseases including acute lung injury (ALI), asthma, rheumatoid arthritis, Parkinson's disease (PD), hepatitis, atherosclerosis, and atopic dermatitis. Cordycepin regulates the NF-κB, RIP2/Caspase-1, Akt/GSK-3β/p70S6K, TGF-β/Smads, and Nrf2/HO-1 signaling pathways among others. Several studies focusing on cordycepin derivatives were reviewed and found to down metabolic velocity of cordycepin and increase its bioavailability. Moreover, cordycepin enhanced immunity, inhibited the proliferation of viral RNA, and suppressed cytokine storms, thereby suggesting its potential to treat COVID-19 and other viral infections. From the collected and reviewed information, this article provides the theoretical basis for the clinical applications of cordycepin and discusses the path for future studies focusing on expanding the medicinal use of cordycepin. Taken together, cordycepin and its analogs show great potential as the next new class of anti-inflammatory agents.

Sufentanil attenuates inflammation and oxidative stress in sepsis-induced acute lung injury by downregulating KNG1 expression

The present study aimed to investigate the effects of sufentanil on sepsis-induced acute lung injury (ALI), and identify the potential molecular mechanisms underlying its effect. In order to achieve this, a rat sepsis model was established. Following treatment with sufentanil, the lung wet/dry (W/D) weight ratio was calculated. Histopathological analysis was performed via hematoxylin and eosin staining. Levels of inflammatory factors in bronchoalveolar lavage fluid were determined via ELISA. Furthermore, malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in tissue homogenates were assessed using commercial kits. Western blot analysis was performed to determine kininogen-1 (KNG1) protein expression. In addition, alveolar epithelial type II cells (AEC II) were stimulated with lipopolysaccharide (LPS) to mimic ALI. The levels of inflammation and oxidative stress were evaluated following overexpression of KNG1. Protein expression levels of nuclear factor-κB (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling were determined via western blot analysis. The results of the present study demonstrated that sufentanil alleviated histopathological injury and the W/D ratio in lung tissue. Following treatment with sufentanil, levels of inflammatory factors also decreased, accompanied by decreased concentrations of MDA, and increased activities of SOD, CAT and GSH-Px. Notably, KNG1 was decreased in lung tissues following treatment with sufentanil. Furthermore, overexpression of KNG1 attenuated the inhibitory effects of sufentanil on LPS-induced inflammation and oxidative stress in AEC II. Sufentanil markedly downregulated NF-κB expression, while upregulating Nrf2 and HO-1 expression levels, which was reversed following overexpression of KNG1. Taken together, the results of the present study suggested that sufentanil may alleviate inflammation and oxidative stress in sepsis-induced ALI by downregulating KNG1 expression.

Systems pharmacology reveals the mechanism of activity of Physalis alkekengi L. var. franchetii against lipopolysaccharide-induced acute lung injury

Acute lung injury (ALI) is an important cause of mortality of patients with sepsis, shock, trauma, pneumonia, multiple transfusions and pancreatitis. Physalis alkekengi L. var. franchetii (Mast.) Makino (PAF) has been extensively used in Chinese folk medicine because of a good therapeutic effect in respiratory diseases. Here, an integrated approach combining network pharmacology, proton nuclear magnetic resonance-based metabolomics, histopathological analysis and biochemical assays was used to elucidate the mechanism of PAF against ALI induced by lipopolysaccharide (LPS) in a mouse model. We found that the compounds present in PAF interact with 32 targets to effectively improve the damage in the lung undergoing ALI. We predicted the putative signalling pathway involved by using the network pharmacology and then used the orthogonal signal correction partial least-squares discriminant analysis to analyse the disturbances in the serum metabolome in mouse. We also used ELISA, RT-qPCR, Western blotting, immunohistochemistry and TUNEL assay to confirm the potential signalling pathways involved. We found that PAF reduced the release of cytokines, such as TNF-α, and the accumulation of oxidation products; decreased the levels of NF-κB, p-p38, ERK, JNK, p53, caspase-3 and COX-2; and enhanced the translocation of Nrf2 from the cytoplasm to the nucleus. Collectively, PAF significantly reduced oxidative stress injury and inflammation, at the same time correcting the energy metabolism imbalance caused by ALI, increasing the amount of antioxidant-related metabolites and reducing the apoptosis of lung cells. These observations suggest that PAF may be an effective candidate preparation alleviating ALI.

Synergistic effect of halofuginone and dexamethasone on LPS‑induced acute lung injury in type II alveolar epithelial cells and a rat model

Acute lung injury (ALI) is characterized by neutrophilic infiltration, uncontrolled oxidative stress and inflammatory processes. Despite various therapeutic regimes having been performed, there remains no effective pharmacotherapy available to treat ALI. Halofuginone (HF), a ketone isolated from Dichroa febrifuga, exhibits significant anti‑inflammatory and antifibrotic effects. Dexamethasone (DEX), a synthetic glucocorticoid, has been routinely used as an adjuvant therapy in treating inflammatory diseases, including ALI. The present study aimed to investigate the effects of the combination of HF and DEX in the treatment of ALI. The present results suggested that the simultaneous administration of HF and DEX markedly decreased the level of pro‑inflammatory cytokines and increased the level of anti‑inflammatory cytokines, as assessed by western blot analysis. In addition, HF and DEX effectively decreased nuclear factor‑κB activity via suppressing the phosphorylation of P65 in lipopolysaccharide (LPS)‑induced human pulmonary alveolar epithelial cells (HPAEpiC) and lung tissues extracted from ALI rats, as determined by immunofluorescence. Furthermore, in vivo experiments demonstrated that the combination of HF and DEX in LPS‑induced ALI rats defended against lung fibrosis, perivascular inflammation, congestion and edema of pulmonary alveoli, as assessed by histopathological analysis, TUNEL staining and immunohistochemistry assay. Taken together, the present study indicated the synergistic effect of HF and DEX on LPS‑induced ALI in HPAEpiC cells and a rat model. These results offer a novel therapeutic approach for the treatment of ALI.

Ameliorative effects of silymarin on HCl-induced acute lung injury in rats; role of the Nrf-2/HO-1 pathway

OBJECTIVES

Aspiration is a common cause of acute lung injury (ALI), which lacks an effective treatment. Inflammation and oxidative stress play key roles in ALI development. Silymarin is an active extract of Silybum marianum plant seeds (milk thistle). Silymarin has potent anti-inflammatory and antioxidant effects; however its role in aspiration induced ALI has not been investigated. The aim of this study is to investigate the role of silymarin in the treatment of hydrochloric acid (HCl) aspiration induced ALI and explores its mechanisms of action.

MATERIALS AND METHODS

The study included three groups of rats: Control non-treated group, ALI group (intra-tracheal HCl injected), and silymarin treated ALI group. White blood cells (WBCs) with differential count, oxidative stress parameters, B-cell lymphoma 2 (Bcl-2), transforming growth factor-beta (TGF-β), cyclooxygenase 2 (COX-2), nuclear factor erythroid 2-related factor-2 (Nrf-2), and heme oxygenase-1 (HO-1) were investigated. Lung tissue histopathology and immunohistochemical expression of survivin and proliferating cell nuclear antigen (PCNA) were also examined.

RESULTS

The results of the study showed that HCL caused histopathological changes in ALI with leukocytopenia and increased oxidative stress biomarkers. It increased TGF-β, up-regulated mRNA expression of COX-2, Nrf-2, and HO-1 and increased survivin and PCNA but decreased Bcl-2. Silymarin ameliorated the histopathological lung injury with further up-regulation of Nrf-2 and HO-1 mRNA and decreased the inflammatory and fibrotic parameters together with up-regulation of the anti-apoptotic and the proliferation parameters.

CONCLUSION

The protective effect of silymarin against ALI is mediated by Nrf-2/HO-1 pathway with subsequent antioxidant, anti-inflammatory, antiapoptotic, and proliferating activities.

Dipeptidyl Peptidase-4 (DPP-4) Inhibitor Saxagliptin Alleviates Lipopolysaccharide-Induced Acute Lung Injury via Regulating the Nrf-2/HO-1 and NF-B Pathways

PURPOSE

We aimed at investigating the effects of Dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin (Saxa) on mouse acute lung injury (ALI)-induced by lipopolysaccharide (LPS) and the potential mechanisms.

MATERIALS/METHODS

Animals were divided into four groups: control, Saxa, LPS, and LPS + Saxa. Histopathology changes of lung tissues were assessed by hematoxylin and eosin staining and periodic acid-Schiff staining. The degree of edema was determined by wet/dry ratio. The levels of oxidative stress markers and inflammatory cytokines in lung homogenate and bronchoalveolar lavage fluid were detected using kits. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to test apoptosis and Western blotting was applied to measure the expression of apoptosis-associated proteins. The expression of nuclear factor erythroid 2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) and nuclear factor-kappa B (NF-κB) pathways were detected by Western blotting.

RESULTS

The results revealed that Saxa attenuated LPS-induced pathological injury and edema. Saxa decreased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), myeloperoxidase (MPO) and increased the levels of superoxide dismutase (SOD) and catalase (CAT). The contents of inflammatory cytokines were reduced in the Saxa intervention group. Saxa attenuated apoptosis accompanied by alterations in the expression of apoptosis-associated proteins. Furthermore, the expression of Nrf-2 and HO-1 were upregulated whereas phospho (p)-NF-κB p65 and phospho-inhibitory subunit of NF-κB alpha (p-IκB-α) were downregulated after Saxa treatment.

CONCLUSION

These findings concluded that Saxa alleviates oxidative stress, inflammation and apoptosis in ALI induced by LPS via modulating the Nrf-2/HO-1 and NF-κB pathways, which provides evidence for employing Saxa in ALI treatment.

Role of Nrf2 and Its Activators in Respiratory Diseases

Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a major regulator of antioxidant response element- (ARE-) driven cytoprotective protein expression. The activation of Nrf2 signaling plays an essential role in preventing cells and tissues from injury induced by oxidative stress. Under the unstressed conditions, natural inhibitor of Nrf2, Kelch-like ECH-associated protein 1 (Keap1), traps Nrf2 in the cytoplasm and promotes the degradation of Nrf2 by the 26S proteasome. Nevertheless, stresses including highly oxidative microenvironments, impair the ability of Keap1 to target Nrf2 for ubiquitination and degradation, and induce newly synthesized Nrf2 to translocate to the nucleus to bind with ARE. Due to constant exposure to external environments, including diverse pollutants and other oxidants, the redox balance maintained by Nrf2 is fairly important to the airways. To date, researchers have discovered that Nrf2 deletion results in high susceptibility and severity of insults in various models of respiratory diseases, including bronchopulmonary dysplasia (BPD), respiratory infections, acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), asthma, idiopathic pulmonary fibrosis (IPF), and lung cancer. Conversely, Nrf2 activation confers protective effects on these lung disorders. In the present review, we summarize Nrf2 involvement in the pathogenesis of the above respiratory diseases that have been identified by experimental models and human studies and describe the protective effects of Nrf2 inducers on these diseases.