Polydatin attenuates reactive oxygen species-induced airway remodeling by promoting Nrf2-mediated antioxidant signaling in asthma mouse model

Gut-lung axis and asthma: A historical review on mechanism and future perspective

BACKGROUND

Gut microbiota are closely related to the development and regulation of the host immune system by regulating the maturation of immune cells and the resistance to pathogens, which affects the host immunity. Early use of antibiotics disrupts the homeostasis of gut microbiota and increases the risk of asthma. Gut microbiota actively interact with the host immune system via the gut-lung axis, a bidirectional communication pathway between the gut and lung. The manipulation of gut microbiota through probiotics, helminth therapy, and fecal microbiota transplantation (FMT) to combat asthma has become a hot research topic. BODY: This review mainly describes the current immune pathogenesis of asthma, gut microbiota and the role of the gut-lung axis in asthma. Moreover, the potential of manipulating the gut microbiota and its metabolites as a treatment strategy for asthma has been discussed.

CONCLUSION

The gut-lung axis has a bidirectional effect on asthma. Gut microecology imbalance contributes to asthma through bacterial structural components and metabolites. Asthma, in turn, can also cause intestinal damage through inflammation throughout the body. The manipulation of gut microbiota through probiotics, helminth therapy, and FMT can inform the treatment strategies for asthma by regulating the maturation of immune cells and the resistance to pathogens.

Nrf-2 as a novel target in radiation induced lung injury

Radiation-induced lung injury (RILI) is a common and fatal complication of chest radiotherapy. The underlying mechanisms include radiation-induced oxidative stress caused by damage to the deoxyribonucleic acid (DNA) and production of reactive oxygen species (ROS), resulting in apoptosis of lung and endothelial cells and recruitment of inflammatory cells and myofibroblasts expressing NADPH oxidase to the site of injury, which in turn contribute to oxidative stress and cytokine production. Nuclear factor erythroid 2-related factor 2 (Nrf-2) is a vital transcription factor that regulates oxidative stress and inhibits inflammation. Studies have shown that Nrf-2 protects against radiation-induced lung inflammation and fibrosis. This review discusses the protective role of Nrf-2 in RILI and its possible mechanisms.

E-Stilbenes: General Chemical and Biological Aspects, Potential Pharmacological Activity Based on the Nrf2 Pathway

Stilbenes are phytoalexins, and their biosynthesis can occur through a natural route (shikimate precursor) or an alternative route (in microorganism cultures). The latter is a metabolic engineering strategy to enhance production due to stilbenes recognized pharmacological and medicinal potential. It is believed that in the human body, these potential activities can be modulated by the regulation of the nuclear factor erythroid derived 2 (Nrf2), which increases the expression of antioxidant enzymes. Given this, our review aims to critically analyze evidence regarding E-stilbenes in human metabolism and the Nrf2 activation pathway, with an emphasis on inflammatory and oxidative stress aspects related to the pathophysiology of chronic and metabolic diseases. In this comprehensive literature review, it can be observed that despite the broad number of stilbenes, those most frequently explored in clinical trials and preclinical studies (in vitro and in vivo) were resveratrol, piceatannol, pterostilbene, polydatin, stilbestrol, and pinosylvin. In some cases, depending on the dose/concentration and chemical nature of the stilbene, it was possible to identify activation of the Nrf2 pathway. Furthermore, the use of some experimental models presented a challenge in comparing results. In view of the above, it can be suggested that E-stilbenes have a relationship with the Nrf2 pathway, whether directly or indirectly, through different biological pathways, and in different diseases or conditions that are mainly related to inflammation and oxidative stress.

Effects of Fermented Polygonum cuspidatum on the Skeletal Muscle Functions

Plant extract fermentation is widely employed to enhance the nutritional and pharmaceutical value of functional foods. Polygonum cuspidatum (Pc) contains flavonoids, anthraquinones, and stilbenes, imparting protective effects against inflammatory diseases, cancer, diabetes, and cardiovascular diseases. However, the effects of fermented Pc on skeletal muscle strength remain unexplored. In this study, we generated fermented Pc using a complex of microorganisms containing Lactobacillus spp. (McPc) and assessed its effects on muscle strength and motor function in mice. Compared to unfermented Pc water extract, elevated levels of emodin and resveratrol were noted in McPc. This was identified and quantified using UPLC-QTOF/MS and HPLC techniques. Gene expression profiling through RNA-seq and quantitative RT-PCR revealed that McPc administration upregulated the expression of genes associated with antioxidants, glycolysis, oxidative phosphorylation, fatty acid oxidation, and mitochondrial biogenesis in cultured C2C12 myotubes and the gastrocnemius muscle in mice. McPc significantly improved skeletal muscle strength, motor coordination, and traction force in mice subjected to sciatic neurectomy and high-fat diet (HFD). McPc administration exhibited more pronounced improvement of obesity, hyperglycemia, fatty liver, and hyperlipidemia in HFD mice compared to control group. These findings support the notion that emodin and resveratrol-enriched McPc may offer health benefits for addressing skeletal muscle weakness.

Immunometabolism in the pathogenesis of asthma

Bronchial asthma is a heterogeneous disease characterised by chronic airway inflammation. A variety of immune cells such as eosinophils, mast cells, T lymphocytes, neutrophils and airway epithelial cells are involved in the airway inflammation and airway hyperresponsiveness in asthma pathogenesis, resulting in extensive and variable reversible expiratory airflow limitation. However, the precise molecular mechanisms underlying the allergic immune responses, particularly immunometabolism, remains unclear. Studies have detected enhanced oxidative stress, and abnormal metabolic progresses of glycolysis, fatty acid and amino acid in various immune cells, inducing dysregulation of innate and adaptive immune responses in asthma pathogenesis. Immunometabolism mechanisms contain multiple signalling pathways, providing novel therapy targets for asthma. This review summarises the current knowledge on immunometabolism reprogramming in asthma pathogenesis, as well as potential therapy strategies.

Phytochemicals as treatment for allergic asthma: Therapeutic effects and mechanisms of action

BACKGROUND

Allergic asthma is an inflammatory disease caused by the immune system's reaction to allergens, inflammation and narrowing of the airways, and the production of more than normal mucus. One of the main reasons is an increased production of inflammatory cytokines in the lungs that leads to the appearance of symptoms of asthma, including inflammation and shortness of breath. On the other hand, it has been proven that phytochemicals with their antioxidant and anti-inflammatory properties can be useful in improving allergic asthma.

PURPOSE

Common chemical treatments for allergic asthma include corticosteroids, which have many side effects and temporarily relieve symptoms but are not a cure. Therefore, taking the help of natural compounds to improve the quality of life of asthmatic patients can be a valuable issue that has been evaluated in the present review.

STUDY DESIGN AND METHODS

In this study, three databases (Scopus, PubMed, and Cochrane) with the keywords: allergic asthma, phytochemical, plant, and herb were evaluated. The primary result was 5307 articles. Non-English, repetitive, and review articles were deleted from the study.

RESULTS AND DISCUSSION

Finally, after carefully reading the articles, 102 were included in the study (2006-2022). The results of this review state that phytochemicals suppress the inflammatory pathways via inhibition of inflammatory cytokines production/secretion, genes, and proteins involved in the inflammation process, reducing oxidative stress indicators and symptoms of allergic asthma, such as cough and mucus production in the lungs.

CONCLUSION

With their antioxidant effects, this study concluded that phytochemicals suppress cytokines and other inflammatory indicators and thus can be considered an adjunctive treatment for improving allergic asthma.

Advances for pharmacological activities of Polygonum cuspidatum - A review

CONTEXT

Polygonum cuspidatum Sieb. et Zucc (Polygonaceae), the root of which is included in the Chinese Pharmcopoeia under the name 'Huzhang', has a long history as a medicinal plant and vegetable. Polygonum cuspidatum has been used in traditional Chinese medicine for the treatment of inflammation, hyperlipemia, etc.

OBJECTIVE

This article reviews the pharmacological action and the clinical applications of Polygonum cuspidatum and its extracts, whether in vivo or in vitro. We also summarized the main phytochemical constituents and pharmacokinetics of Polygonum cuspidatum and its extracts.

METHODS

The data were retrieved from major medical databases, such as CNKI, PubMed, and SinoMed, from 2014 to 2022. Polygonum cuspidatum, pharmacology, toxicity, clinical application, and pharmacokinetics were used as keywords.

RESULTS

The rhizomes, leaves, and flowers of Polygonum cuspidatum have different phytochemical constituents. The plant contains flavonoids, anthraquinones, and stilbenes. Polygonum cuspidatum and the extracts have anti-inflammatory, antioxidation, anticancer, heart protection, and other pharmacological effects. It is used in the clinics to treat dizziness, headaches, traumatic injuries, and water and fire burns.

CONCLUSIONS

Polygonum cuspidatum has the potential to treat many diseases, such as arthritis, ulcerative colitis, asthma, and cardiac hypertrophy. It has a broad range of medicinal applications, but mainly focused on root medication; its aerial parts should receive more attention. Pharmacokinetics also need to be further investigated.

Epithelial cell dysfunction in chronic rhinosinusitis: the epithelial-mesenchymal transition

INTRODUCTION

Epithelial-mesenchymal transition (EMT) is a type of epithelial cell dysfunction, which is widely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS), especially CRS with nasal polyps, and contributes to pathogenesis of the disease. EMT is mediated via complex mechanisms associated with multiple signaling pathways.

AREAS COVERED

We have summarized the underlying mechanisms and signaling pathways promoting EMT in CRS. Strategies or drugs/agents targeting the genes and pathways related to the regulation of EMT are also discussed for their potential use in the treatment of CRS and asthma. A literature search of studies published in English from 2000 to 2023 was conducted using the PubMed database, employing CRS, EMT, signaling, mechanisms, targeting agents/drugs, as individual or combinations of search terms.

EXPERT OPINION

EMT in nasal epithelium not only leads to epithelial cell dysfunction but also plays an important role in nasal tissue remodeling in CRS. A comprehensive understanding of the mechanisms underlying EMT and the development of drugs/agents targeting these mechanisms may provide new treatment strategies for CRS.

Protective effects of polydatin on ileum injury in mice exposed to aflatoxin B1

Aflatoxin B1 (AFB1) is an extremely hazardous food/feed pollutant, posing a serious threat to health of human and animals. Particularly, exposure to AFB1 provokes enterocytes oxidative stress and inflammation, which lead to intestinal damage. Polydatin (PD), a stilbenoid glucoside, is known to possess antioxidant and anti-inflammatory properties and is being investigated for use in various disorders. The present study was intended at investigating the protective efficacy of polydatin against AFB1-induced ileum damage in mice. Kunming male mice received oral gavage of AFB1 (300 μg/kg) and PD (100 mg/kg) for 18 days. The results showed that mice exposed to AFB1 exhibited the impaired morphology, the suppressed disaccharidase activities, the down-regulated mRNA expressions of tight junction protein genes, oxidative stress, inflammation and the up-regulated mRNA expressions of genes related to mitophagy in the ileum, whereas PD treatment reversed the AFB1-induced disruption of ileal structure, digestion, barrier function, redox and immune status. The findings of the present study suggested that polydatin may have a potential benefit in preventing AFB1-induced ileum damage.

Polydatin inhibits mitochondrial damage and mitochondrial ROS by promoting PINK1-Parkin-mediated mitophagy in allergic rhinitis

Polydatin (PD), a natural product derived from Polygonum cuspidatum, has anti-inflammatory and antioxidant effects and has significant benefits in treating allergic diseases. However, its role and mechanism in allergic rhinitis (AR) have not been fully elucidated. Herein, we investigated the effect and mechanism of PD in AR. AR model was established in mice with OVA. Human nasal epithelial cells (HNEpCs) were stimulated with IL-13. HNEpCs were also treated with an inhibitor of mitochondrial division or transfected with siRNA. The levels of IgE and cellular inflammatory factors were examined by enzyme linked immunosorbent assay and flow cytometry. The expressions of PINK1, Parkin, P62, LC3B, NLRP3 inflammasome proteins, and apoptosis proteins in nasal tissues and HNEpCs were measured by Western blot. We found that PD suppressed OVA-induced epithelial thickening and eosinophil accumulation in the nasal mucosa, reduced IL-4 production in NALF, and regulated Th1/Th2 balance. In addition, mitophagy was induced in AR mice after OVA challenge and in HNEpCs after IL-13 stimulation. Meanwhile, PD enhanced PINK1-Parkin-mediated mitophagy but decreased mitochondrial reactive oxygen species (mtROS) production, NLRP3 inflammasome activation, and apoptosis. However, PD-induced mitophagy was abrogated after PINK1 knockdown or Mdivi-1 treatment, indicating a key role of the PINK1-Parkin in PD-induced mitophagy. Moreover, mitochondrial damage, mtROS production, NLRP3 inflammasome activation, and HNEpCs apoptosis under IL-13 exposure were more severe after PINK1 knockdown or Mdivi-1 treatment. Conclusively, PD may exert protective effects on AR by promoting PINK1-Parkin-mediated mitophagy, which further suppresses apoptosis and tissue damage in AR through decreasing mtROS production and NLRP3 inflammasome activation.

Chinese medicinal plant Polygonum cuspidatum ameliorates silicosis via suppressing the Wnt/β-catenin pathway

Polygonum cuspidatum (PC) extract has effect on silica-induced pulmonary fibrosis. This study aimed to explore the anti-pulmonary-fibrosis effects and mechanism of PC. Sprague–Dawley rat model was constructed by inhalation of silicon dioxide suspension through tracheal intubation method. And histopathological examination showed that PC inhibited inflammatory cell infiltration, fibrous and collagen hyperplasia, and protected the normal structure of alveoli. TUNEL assay declared that PC retarded cell apoptosis. Meanwhile, up-regulation of basic fibroblast growth factor, plated-derived growth factor, and TNF-α in silicosis rats was decreased by PC addition. In addition, human fetal lung fibroblasts (HFL-1) cells were stimulated with transforming growth factor-β1 (TGF-β1). PC administration increased the proliferation and invasion of TGF-β1-stimulated HFL-1 cells whereas decreased cell apoptosis. Moreover, western blotting exhibited that PC treatment decreased the expression of α-smooth muscle actin, collagen I, and collagen III in silicosis rats and TGF-β1-stimulated HFL-1 cells. Furthermore, the levels of Wnt/β-catenin pathway proteins were up-regulated in silicosis rats and TGF-β1-stimulated HFL-1 cells, which were weakened by PC treatment. Meanwhile, Wnt3a (an activator of Wnt/β-catenin) addition reversed the effect of PC addition. In conclusion, PC prevents silica-induced fibrosis through inhibiting the Wnt/β-catenin pathway.

Polydatin attenuates tubulointerstitial fibrosis in diabetic kidney disease by inhibiting YAP expression and nuclear translocation

The activation of Yes-associated protein (YAP) pathway is mutually causal with the increase of extracellular matrix (ECM) stiffness. Polydatin (PD) has been proved to have anti-fibrosis effect in diabetic kidney disease (DKD), but it is still a mystery whether PD participates in YAP-related mechano-transduction. Therefore, this study intends to solve the following two problems: 1) To construct an in vitro system of polyacrylamide hydrogels (PA gels) based on the true stiffness of kidneys in healthy and DKD rats, and observe the effect of PD on pathological matrix stiffness-induced YAP expression in renal fibroblasts; 2) Compared with verteporfin (VP), a pharmacological inhibitor of YAP, to explore whether the therapeutic effect of PD on DKD in vivo model is related to the regulation of YAP. In this study, the in vitro system of PA gels with 3 kPa, 12 kPa and 30 kPa stiffness was constructed and determined for the first time to simulate the kidney stiffness of healthy rats, rats with DKD for 8 weeks and 16 weeks, respectively. Compared with the PA gels with 3 kPa stiffness, the PA gels with 12 kPa and 30 kPa stiffness significantly increased the expression of YAP, α-smooth muscle actin (α-SMA) and collagen I, and the production of reactive oxygen species (ROS) in renal fibroblasts, and the PA gels with 30 kPa stiffness were the highest. PD significantly inhibited the above-mentioned changes of fibroblasts induced by pathological matrix stiffness, suggesting that the inhibition of PD on fibroblast-to-myofibroblast transformation and ECM production was at least partially associated with regulating YAP-related mechano-transduction pathway. Importantly, the inhibitory effect of PD on YAP expression and nuclear translocation in kidneys of DKD rats is similar to that of VP, but PD is superior to VP in reducing urinary protein, blood glucose, blood urea nitrogen and serum creatinine, as well as decreasing the expression of α-SMA and collagen I, ROS overproduction and renal fibrosis. Our results prove for the first time from the biomechanical point of view that PD is a potential therapeutic strategy for delaying the progression of renal fibrosis by inhibiting YAP expression and nuclear translocation.

Polydatin: Pharmacological Mechanisms, Therapeutic Targets, Biological Activities, and Health Benefits

Polydatin is a natural potent stilbenoid polyphenol and a resveratrol derivative with improved bioavailability. Polydatin possesses potential biological activities predominantly through the modulation of pivotal signaling pathways involved in inflammation, oxidative stress, and apoptosis. Various imperative biological activities have been suggested for polydatin towards promising therapeutic effects, including anticancer, cardioprotective, anti-diabetic, gastroprotective, hepatoprotective, neuroprotective, anti-microbial, as well as health-promoting roles on the renal system, the respiratory system, rheumatoid diseases, the skeletal system, and women's health. In the present study, the therapeutic targets, biological activities, pharmacological mechanisms, and health benefits of polydatin are reviewed to provide new insights to researchers. The need to develop further clinical trials and novel delivery systems of polydatin is also considered to reveal new insights to researchers.

The Role of Nrf2 in Pulmonary Fibrosis: Molecular Mechanisms and Treatment Approaches

Pulmonary fibrosis is a chronic, progressive, incurable interstitial lung disease with high mortality after diagnosis and remains a global public health problem. Despite advances and breakthroughs in understanding the pathogenesis of pulmonary fibrosis, there are still no effective methods for the prevention and treatment of pulmonary fibrosis. The existing treatment options are imperfect, expensive, and have considerable limitations in effectiveness and safety. Hence, there is an urgent need to find novel therapeutic targets. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a central regulator of cellular antioxidative responses, inflammation, and restoration of redox balance. Accumulating reports reveal that Nrf2 activators exhibit potent antifibrosis effects and significantly attenuate pulmonary fibrosis in vivo and in vitro. This review summarizes the current Nrf2-related knowledge about the regulatory mechanism and potential therapies in the process of pulmonary fibrosis. Nrf2 orchestrates the activation of multiple protective genes that target inflammation, oxidative stress, fibroblast–myofibroblast differentiation (FMD), and epithelial–mesenchymal transition (EMT), and the mechanisms involve Nrf2 and its downstream antioxidant, Nrf2/HO−1/NQO1, Nrf2/NOX4, and Nrf2/GSH signaling pathway. We hope to indicate potential for Nrf2 system as a therapeutic target for pulmonary fibrosis.

Polydatin activates the Nrf2/HO-1 signaling pathway to protect cisplatin-induced hearing loss in guinea pigs

Irreversible sensorineural hearing loss is one of the most common side effects after cisplatin treatment. Prevention and reversal of hearing loss caused by cisplatin are of great importance for cancer patients, especially children. Oxidative stress is an important cause of hearing loss resulted from cisplatin, unfortunately, there is no drug yet available that can completely prevent and reverse the ototoxicity from cisplatin. Polydatin (PD) possesses excellent antioxidant and anti-inflammatory effects, however, its role in the cisplatin-induced hearing loss has not been investigated. Herein, we have explored the preventive and therapeutic effects of PD on cisplatin-induced hearing loss and the possible underlying mechanisms. In the in vivo setting with guinea pigs, we have demonstrated that PD can reduce the threshold shift of auditory brainstem response (ABR) caused by cisplatin, promote the nuclear translocation of Nuclear factor erythroid-2 related factor 2 (Nrf2), increase the expression of Nrf2 and heme oxygenase-1 (HO-1), and thus reduce the loss of outer hair cells (OHCs). PD can ameliorate cisplatin-induced hearing loss through activating the Nrf2/HO-1 signaling pathway. This study provides a potential strategy for preventing and improving hearing loss resulted from cisplatin treatment in clinics.

The Role and Mechanisms of Traditional Chinese Medicine for Airway Inflammation and Remodeling in Asthma: Overview and Progress

Asthma as an individual disease has blighted human health for thousands of years and is still a vital global health challenge at present. Though getting much progress in the utilization of antibiotics, mucolytics, and especially the combination of inhaled corticosteroids (ICS) and long-acting β-agonists (LABA), we are confused about the management of asthmatic airway inflammation and remodeling, which directly threatens the quality of life for chronic patients. The blind addition of ICS will not benefit the remission of cough, wheeze, or sputum, but to increase the risk of side effects. Thus, it is necessary to explore an effective therapy to modulate asthmatic inflammation and airway remodeling. Traditional Chinese Medicine (TCM) has justified its anti-asthma effect in clinical practice but its underlying mechanism and specific role in asthma are still unknown. Some animal studies demonstrated that the classic formula, direct exacts, and natural compounds isolated from TCM could significantly alleviate airway structural alterations and exhibit the anti-inflammatory effects. By investigating these findings and data, we will discuss the possible pathomechanism underlined airway inflammation and remodeling in asthma and the unique role of TCM in the treatment of asthma through regulating different signaling pathways.

The Immune Mechanisms of Severe Equine Asthma-Current Understanding and What Is Missing

Severe equine asthma is a chronic respiratory disease of adult horses, occurring when genetically susceptible individuals are exposed to environmental aeroallergens. This results in airway inflammation, mucus accumulation and bronchial constriction. Although several studies aimed at evaluating the genetic and immune pathways associated with the disease, the results reported are inconsistent. Furthermore, the complexity and heterogeneity of this disease bears great similarity to what is described for human asthma. Currently available studies identified two chromosome regions (ECA13 and ECA15) and several genes associated with the disease. The inflammatory response appears to be mediated by T helper cells (Th1, Th2, Th17) and neutrophilic inflammation significantly contributes to the persistence of airway inflammatory status. This review evaluates the reported findings pertaining to the genetical and immunological background of severe equine asthma and reflects on their implications in the pathophysiology of the disease whilst discussing further areas of research interest aiming at advancing treatment and prognosis of affected individuals.

Bulbus Fritillariae Cirrhosae as a Respiratory Medicine: Is There a Potential Drug in the Treatment of COVID-19?

Bulbus fritillariae cirrhosae (BFC) is one of the most used Chinese medicines for lung disease, and exerts antitussive, expectorant, anti-inflammatory, anti-asthmatic, and antioxidant effects, which is an ideal therapeutic drug for respiratory diseases such as ARDS, COPD, asthma, lung cancer, and pulmonary tuberculosis. Through this review, it is found that the therapeutic mechanism of BFC on respiratory diseases exhibits the characteristics of multi-components, multi-targets, and multi-signaling pathways. In particular, the therapeutic potential of BFC in terms of intervention of “cytokine storm”, STAT, NF-κB, and MAPK signaling pathways, as well as the renin-angiotensin system (RAS) that ACE is involved in. In the “cytokine storm” of SARS-CoV-2 infection there is an intense inflammatory response. ACE2 regulates the RAS by degradation of Ang II produced by ACE, which is associated with SARS-CoV-2. For COVID-19, may it be a potential drug? This review summarized the research progress of BFC in the respiratory diseases, discussed the development potentiality of BFC for the treatment of COVID-19, explained the chemical diversity and biological significance of the alkaloids in BFC, and clarified the material basis, molecular targets, and signaling pathways of BFC for the respiratory diseases. We hope this review can provide insights on the drug discovery of anti-COVID-19.

Emerging Roles of Non-Coding RNAs in Childhood Asthma

Asthma is a chronic airway inflammatory disease in children characterized by airway inflammation, airway hyperresponsiveness and airway remodeling. Childhood asthma is usually associated with allergy and atopy, unlike adult asthma, which is commonly associated with obesity, smoking, etc. The pathogenesis and diagnosis of childhood asthma also remains more challenging than adult asthma, such as many diseases showing similar symptoms may coexist and be confused with asthma. In terms of the treatment, although most childhood asthma can potentially be self-managed and controlled with drugs, approximately 5-10% of children suffer from severe uncontrolled asthma, which carries significant health and socioeconomic burdens. Therefore, it is necessary to explore the pathogenesis of childhood asthma from a new perspective. Studies have revealed that non-coding RNAs (ncRNAs) are involved in the regulation of respiratory diseases. In addition, altered expression of ncRNAs in blood, and in condensate of sputum or exhalation affects the progression of asthma via regulating immune response. In this review, we outline the regulation and pathogenesis of asthma and summarize the role of ncRNAs in childhood asthma. We also hold promise that ncRNAs may be used for the development of biomarkers and support a new therapeutic strategy for childhood asthma.

Old dog, new tricks: Polydatin as a multitarget agent for current diseases

Polydatin (PD) is a natural single-crystal product that is primarily extracted from the traditional plant Polygonum cuspidatum Sieb. et Zucc. Early research showed that PD exhibited a variety of biological activities. PD has attracted increasing research interest since 2014, but no review comprehensively summarized the new findings. A great gap between its biological activities and drug development remains. It is necessary to summarize new findings on the pharmacological effects of PD on current diseases. We propose that PD will most likely be used in cardiac and cerebral ischaemia/reperfusion-related diseases and atherosclerosis in the future. The present work classified these new findings according to diseases and summarized the main effects of PD via specific mechanisms of action. In summary, we found that PD played a therapeutic role in a variety of diseases, primarily via five mechanisms: antioxidative effects, antiinflammatory effects, regulation of autophagy and apoptosis, maintenance of mitochondrial function, and lipid regulation.

PPM1A as a key target of the application of Jiawei‑Maxing‑Shigan decoction for the attenuation of radiation‑induced epithelial‑mesenchymal transition in type II alveolar epithelial cells

Radiation‑induced lung tissue injury is an important reason for the limited application of radiotherapy on thoracic malignancies. Previously, we reported that administration of Jiawei‑Maxing‑Shigan decoction (JMSD) attenuated the radiation‑induced epithelial‑mesenchymal transition (EMT) in alveolar epithelial cells (AECs) via TGF‑β/Smad signaling. The present study aimed to examine the role of protein phosphatase Mg²⁺/Mn²⁺‑dependent 1A (PPM1A) in the anti‑EMT activity of JMSD on AECs. The components in the aqueous extract of JMSD were identified by high‑performance liquid chromatography coupled with electrospray mass spectrometry. Primary rat type II AECs were treated with radiation (60Co γ‑ray at 8 Gy) and JMSD‑medicated serum. PPM1A was overexpressed and knocked down in the AECs via lentivirus transduction and the effects of JMSD administration on the key proteins related to TGF‑β1/Smad signaling were measured by western blotting. It was found that radiation decreased the PPM1A expression in the AECs and JMSD‑medicated serum upregulated the PPM1A expressions in the radiation‑induced AECs. PPM1A overexpression increased the E‑cadherin level but decreased the phosphorylated (p‑)Smad2/3, vimentin and α‑smooth muscle actin (α‑SMA) levels in the AECs. By contrast, the PPM1A knockdown decreased the E‑cadherin level and increased the p‑Smad2/3, vimentin and α‑SMA levels in the AECs and these effects could be blocked by SB431542 (TGF‑β1/Smad signaling inhibitor). JMSD administration increased the E‑cadherin level and decreased the p‑Smad2/3, vimentin and α‑SMA levels in the AECs; however, these effects could be blocked by siPPM1A‑2. In conclusion, PPM1A is a key target of JMSD administration for the attenuation of the radiation‑induced EMT in primary type II AECs via the TGF‑β1/Smad pathway.

Atractylon Treatment Attenuates Pulmonary Fibrosis via Regulation of the mmu_circ_0000981/miR-211-5p/TGFBR2 Axis in an Ovalbumin-Induced Asthma Mouse Model

Asthma-induced pulmonary fibrosis (PF) is an important public health concern that has few treatment options given its poorly understood etiology; however, the epithelial to mesenchymal transition (EMT) of pulmonary epithelial cells has been implicated to play an important role in inducing PF. Although previous studies have found atractylon (Atr) to have anti-inflammatory effects, whether Atr has anti-PF abilities remains unknown. The purpose of the current study was to validate the protective efficiency of Atr in both an animal model of ovalbumin (OVA)-induced asthma and an EMT model induced by transforming growth factor-β1 (TGF-β1) using TC-1 cells. The results of this study revealed that Atr treatment suppressed OVA-induced PF via fibrosis-related protein expression. Atr treatment suppressed OVA-induced circRNA-0000981 and TGFBR2 expression but promoted miR-211-5p expression. In vivo studies revealed that Atr suppressed TGF-β1-induced EMT and fibrosis-related protein expression via suppressing circRNA-0000981 and TGFBR2 expression. The results also suggested that the downregulation of circRNA-0000981 expression suppressed TGFBR2 by sponging miR-211-5p, which was validated by a luciferase reporter assay. Collectively, the findings of the present study suggest that Atr treatment attenuates PF by regulating the mmu_circ_0000981/miR-211-5p/TGFBR2 axis in an OVA-induced asthma mouse model.

Investigation of the Active Ingredients and Mechanism of Polygonum cuspidatum in Asthma Based on Network Pharmacology and Experimental Verification

Background

Polygonum cuspidatum is a Chinese medicine commonly used to treat phlegm-heat asthma. However, its anti-asthmatic active ingredients and mechanism are still unknown. The aim of this study was to predict the active ingredients and pathways of Polygonum cuspidatum and to further explore the potential molecular mechanism in asthma by using network pharmacology.

Methods

The active ingredients and their targets related to Polygonum cuspidatum were seeked out with the TCM systematic pharmacology analysis platform (TCMSP), and the ingredient-target network was constructed. The GeneCards, DrugBank and OMIM databases were used to collect and screen asthma targets, and then the drug-target-disease interaction network was constructed with Cytoscape software. A target protein-protein interaction (PPI) network was constructed using the STRING database to screen key targets. Finally, GO and KEGG analyses were used to identify biological processes and signaling pathways. The anti-asthmatic effects of Polygonum cuspidatum and its active ingredients were tested in vitro for regulating airway smooth muscle (ASM) cells proliferation and MUC5AC expression, two main symptoms of asthma, by using Real-time PCR, Western blotting, CCK-8 assays and annexin V-FITC staining.

Results

Twelve active ingredients in Polygonum cuspidatum and 479 related target proteins were screened in the relevant databases. Among these target proteins, 191 genes had been found to be differentially expressed in asthma. PPI network analysis and KEGG pathway enrichment analysis predicted that the Polygonum cuspidatum could regulate the AKT, MAPK and apoptosis signaling pathways. Consistently, further in vitro experiments demonstrated that Polygonum cuspidatum and resveratrol (one active ingredient of Polygonum cuspidatum) were shown to inhibit ASM cells proliferation and promoted apoptosis of ASM cells. Furthermore, Polygonum cuspidatum and resveratrol inhibited PDGF-induced AKT/mTOR activation in ASM cells. In addition, Polygonum cuspidatum decreased H₂O₂ induced MUC5AC overexpression in airway epithelial NCI-H292 cells.

Conclusion

Polygonum cuspidatum could alleviate the symptoms of asthma including ASM cells proliferation and MUC5AC expression through the mechanisms predicted by network pharmacology, which provides a basis for further understanding of Polygonum cuspidatum in the treatment of asthma.

The upshot of Polyphenolic compounds on immunity amid COVID-19 pandemic and other emerging communicable diseases: An appraisal

Polyphenols are a large family of more than 10,000 naturally occurring compounds, which exert countless pharmacological, biological and physiological benefits for human health including several chronic diseases such as cancer, diabetes, cardiovascular, and neurological diseases. Their role in traditional medicine, such as the use of a wide range of remedial herbs (thyme, oregano, rosemary, sage, mint, basil), has been well and long known for treating common respiratory problems and cold infections. This review reports on the most highlighted polyphenolic compounds present in up to date literature and their specific antiviral perceptive properties that might enhance the body immunity facing COVID-19, and other viral infectious diseases. In fact, several studies and clinical trials increasingly proved the role of polyphenols in controlling numerous human pathogens including SARS and MERS, which are quite similar to COVID-19 through the enhancement of host immune response against viral infections by different biological mechanisms. Thus, polyphenols ought to be considered as a potential and valuable source for designing new drugs that could be used effectively in the combat against COVID-19 and other rigorous diseases.

The Role of Neutrophils in the Pathophysiology of Asthma in Humans and Horses

Asthma is a common and debilitating chronic airway disease that affects people and horses of all ages worldwide. While asthma in humans most commonly involves an excessive type 2 immune response and eosinophilic inflammation, neutrophils have also been recognized as key players in the pathophysiology of asthma, including in the severe asthma phenotype where neutrophilic inflammation predominates. Severe equine asthma syndrome (sEAS) features prominent neutrophilic inflammation and has been increasingly used as a naturally occurring animal model for the study of human neutrophilic asthma. This comparative review examines the recent literature in order to explore the role of neutrophil inflammatory functions in the pathophysiology and immunology of asthma in humans and horses.

Herbal decoction Divya-Swasari-Kwath attenuates airway inflammation and remodeling through Nrf-2 mediated antioxidant lung defence in mouse model of allergic asthma

BACKGROUND AND PURPOSE

Asthma is a chronic respiratory disease orchestrated by immune and structural cells. Identification of novel therapeutic strategies are needed for asthma due to the limitations of existing therapies. We have validated the anti-inflammatory, anti-asthmatic and immunomodulatory therapeutic properties of herbal decoction, Divya-Swasari-Kwath (DSK) using mouse model of ovalbumin (OVA) induced allergic asthma.

METHODS AND RESULTS

HPLC analysis identified the presence of Rutin, Glycyrrchzin, Gallic acid, Cinnamic acid, Chlorogenic acid, Caffeic acid and Piperine as bioactive herbal metabolites in DSK. Therapeutic treatment with herbal decoction DSK significantly alleviated the pathological features of allergic asthma including inflammatory cell accumulation in Broncho-Alveolar Lavage (BAL) fluids, specifically lymphocytes and eosinophils, lung inflammation, oxidative stress, airway remodelling, and pro-inflammatory cytokine levels. H&E analysis of lung tissue sections identified attenuated inflammatory cell infiltration and thickening of bronchial epithelium by DSK. PAS staining and MT staining identified decrease in OVA-induced mucus hyper secretion and peri-bronchial collagen deposition respectively, upon DSK treatment. Treatment with DSK increased the mRNA expression of antioxidative defence gene Nrf-2 and its downstream target genes HO-1 and NQO-1. In the same line, biochemical analysis for the markers of oxidative/antioxidant system confirmed the restoration of activity of Catalase, GPx, SOD and EPO and the levels of GSH, GSSG, MDA and Nitrite in whole lungs. In line with PAS staining, DSK treatment decreased the OVA-induced expression of Muc5AC and Muc5B genes. DSK treatment reduced the steady state mRNA expression levels of IL-6, IL-1β, TNF-α, IL-4, -5, -33, IFN-γ in whole lung; and IL-6, TNF-α and IL-1β protein levels in BALF.

CONCLUSION

Collectively, our results suggest that herbal decoction DSK is effective in protecting against allergic airway inflammation and remodelling by regulating anti-oxidant mechanisms. We postulate that DSK could be the potential therapeutic option for allergic asthma management.

The NRF2-LOC344887 signaling axis suppresses pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible disease characterized by an increase in differentiation of fibroblasts to myofibroblasts and excessive accumulation of extracellular matrix in lung tissue. Pharmacological activation of NRF2 has proved to be a valuable antifibrotic approach, however the detailed mechanisms of how NRF2 mediates antifibrotic function remain unclear. In this study, we found that the antifibrotic function of sulforaphane (SFN), an NRF2 activator, was largely dependent on LOC344887, a long noncoding RNA. Two functional AREs were identified in both the promoter and intron 1 of LOC344887, which defines LOC344887 as a novel anti-fibrotic NRF2 target gene. RNA-seq analysis revealed that LOC344887 controls genes and signaling pathways associated with fibrogenesis. Deletion or downregulation of LOC344887 enhanced expression of CDH2/N-cadherin, as well as a number of other fibrotic genes and blunted the antifibrotic effects of SFN. Furthermore, LOC344887-mediated downregulation of fibrotic genes may involve the PI3K-AKT signaling pathway, as pharmacologic inhibition of PI3K activity blocked the effects of LOC344887 knockdown. Our findings demonstrate that NRF2-mediated LOC344887 upregulation contributes to the antifibrotic potential of SFN by repressing the expression of CDH2 and other fibrotic genes, providing novel insight into how NRF2 controls the regulatory networks of IPF. This study provides a better understanding of the molecular mechanisms of NRF2 activators against pulmonary fibrosis and presents a novel therapeutic axis for prevention and intervention of fibrosis-related diseases.

Melatonin prevents LPS-induced epithelial-mesenchymal transition in human alveolar epithelial cells via the GSK-3β/Nrf2 pathway

BACKGROUND

Oxidative stress plays a critical role in pulmonary fibrosis after acute lung injury (ALI), and epithelial-mesenchymal transition (EMT) events are involved in this process. The purpose of this study was to investigate the protective effects of melatonin, a natural antioxidant, on lipopolysaccharide (LPS)-induced EMT in human alveolar epithelial cells.

METHODS

Human type II alveolar epithelial cell-derived A549 cells were incubated with LPS and melatonin alone or in combination for up to 24 h. The morphological changes of the treated cells were evaluated as well as indexes of oxidative stress. EMT-related proteins and the Nrf2 signaling pathway were detected by western blot analysis and immunofluorescence staining, respectively. To further investigate the underlying mechanisms, the effects of melatonin on cells transfected Nrf2 short hairpin RNA (shRNA) and the PI3K / GSK-3β signaling pathway were evaluated.

RESULTS

Treatment with melatonin upregulated Nrf2 expression, inhibited LPS-induced cell morphological change, reversed the expressions of EMT-related proteins, and reduced reactive oxygen species (ROS) production in A549 cells, as well as the levels of malondialdehyde (MDA) and anti-oxidative enzymes. Yet, the effects of melatonin were almost completely abolished in cells transfected Nrf2 shRNA. Furthermore, the data demonstrated that melatonin could activate the PI3K/AKT signaling pathway, resulting in phosphorylation of GSK-3β (Ser9) and upregulation of the Nrf2 protein in A549 cells, which ultimately attenuated LPS-induced EMT.

CONCLUSION

The present study is the first to demonstrate that melatonin can protect human alveolar epithelial cells against oxidative stress by effectively inhibiting LPS-induced EMT, which was mostly dependent on upregulation of the Nrf2 pathway via the PI3K/GSK-3β axis. Further studies are warranted to investigate the role of melatonin for the treatment of oxidative stress-associated diseases, as well as pulmonary fibrosis after ALI.

Protective Effect of Polydatin on Jejunal Mucosal Integrity, Redox Status, Inflammatory Response, and Mitochondrial Function in Intrauterine Growth-Retarded Weanling Piglets

Intrauterine growth retardation (IUGR) delays the gut development of neonates, but effective treatment strategies are still limited. This study used newborn piglets as a model to evaluate the protective effect of polydatin (PD) against IUGR-induced intestinal injury. In total, 36 IUGR piglets and an equal number of normal birth weight (NBW) littermates were fed either a basal diet or a PD-supplemented diet from 21 to 35 days of age. Compared with NBW, IUGR induced jejunal damage and barrier dysfunction of piglets, as indicated by observable bacterial translocation, enhanced apoptosis, oxidative and immunological damage, and mitochondrial dysfunction. PD treatment decreased bacterial translocation and inhibited the IUGR-induced increases in circulating diamine oxidase activity (P = 0.039) and D-lactate content (P = 0.004). The apoptotic rate (P = 0.024) was reduced by 35.2% in the PD-treated piglets, along with increases in villus height (P = 0.033) and in ratio of villus height to crypt depth (P = 0.049). PD treatment promoted superoxide dismutase (P = 0.026) and glutathione S-transferase activities (P = 0.006) and reduced malondialdehyde (P = 0.015) and 8-hydroxy-2′-deoxyguanosine accumulation (P = 0.034) in the jejunum. The PD-treated IUGR piglets showed decreased jejunal myeloperoxidase activity (P = 0.029) and tumor necrosis factor alpha content (P = 0.035) than those received a basal diet. PD stimulated nuclear sirtuin 1 (P = 0.028) and mitochondrial citrate synthase activities (P = 0.020) and facilitated adenosine triphosphate production (P = 0.009) in the jejunum of piglets. Furthermore, PD reversed the IUGR-induced declines in mitochondrial DNA content (P = 0.048), the phosphorylation of adenosine monophosphate-activated protein kinase alpha (P = 0.027), and proliferation-activated receptor gamma coactivator 1 alpha expression (P = 0.033). Altogether, the results indicate that PD may improve jejunal integrity, mitigate mucosal oxidative and immunological damage, and facilitate mitochondrial function in IUGR piglets.

The Antioxidant Rosmarinic Acid Ameliorates Oxidative Lung Damage in Experimental Allergic Asthma via Modulation of NADPH Oxidases and Antioxidant Enzymes

Oxidative stress can induce lung damage and aggravate airway inflammation in asthma. Previously, we reported that rosmarinic acid (RA) exerted strong anti-inflammatory effects in a mouse allergic asthma model. Therefore, we hypothesized that RA might also have antioxidative effects in a superimposed asthma mouse model with oxidative lung damage challenged with ovalbumin (Ova) and hydrogen peroxide (H2O2). We evaluated the antioxidative and anti-asthmatic activity of RA and explored its possible mechanisms of action. Mice sensitized to Ova and challenged with Ova and H2O2 were treated with RA 1 h after challenge. RA treatment greatly diminished the number of inflammatory cells; decreased IL-4, IL-5, and IL-13 production; increased IFN-γ secretion; significantly downregulated ROS production; and markedly upregulated the activities of SOD, GPx, and CAT. Furthermore, RA treatment resulted in a significant increase in the expression of Cu/Zn SOD and a notable reduction in NOX-2 and NOX-4 expression in lung tissues. These findings suggest that RA may effectively alleviate oxidative lung damage and airway inflammation in asthma.

Bufei Decoction Alleviated Bleomycin-Induced Idiopathic Pulmonary Fibrosis in Mice by Anti-Inflammation

Objective

This study aimed to investigate the mechanistic action and therapeutic effects of Bufei decoction on idiopathic pulmonary fibrosis (IPF) after inhalation of bleomycin.

Methods

Pulmonary fibrosis model in mice was prepared by atomization inhalation of bleomycin. Then, the mice were randomly divided into five groups (control group, model group, positive group, and treatment group) and administrated the drugs for 4 weeks. H&E and Masson's staining of lung tissues were used to observe the morphological changes and deposition of fibers, and the degree of fibrosis was evaluated by hydroxyproline content. The expression and activation of NF-κB were determined by western blotting and immunohistochemistry. The infiltration of macrophages was detected by immunostaining of CD45 and F4/80 in lung tissues.

Results

In mouse IPF, Bufei decoction alleviated the pathological changes and the deposition of fibrosis by decreasing the content of hydroxyproline of lung tissues. The antipulmonary fibrosis might rely on the effects of preventing the infiltration of inflammatory cells and inhibiting the expression and activation of NF-κB in lung tissue.

Conclusion

Bufei decoction improved the process of pulmonary fibrosis by regulating the activation and expression of the NF-κB signal transduction pathway, which provided a therapeutic option for IPF patients.

Qi-Xian Decoction Upregulated E-cadherin Expression in Human Lung Epithelial Cells and Ovalbumin-Challenged Mice by Inhibiting Reactive Oxygen Species-Mediated Extracellular-Signal-Regulated Kinase (ERK) Activation

Background

Loss of the epithelial barrier is characterized by a reduction in E-cadherin expression and is a hallmark of asthma. Qi-xian decoction (QXT) is a Chinese medicinal formula that has been used to effectively treat asthma. This study aimed to investigate the effect of QXT on E-cadherin expression in human lung epithelial 16HBE cells and ovalbumin-challenged mice and to explore the underlying molecular mechanism.

Material/Methods

Ovalbumin (OVA)-induced mice were used as a model of asthma. Real-time PCR and Western blotting were utilized to examine mRNA and protein levels. Lung tissue reactive oxygen species (ROS) levels were evaluated using dichloro-dihydro-fluorescein diacetate (DCFH-DA). Serum superoxide dismutase (SOD) and the total antioxidant capacity (TAOC) were measured via enzyme-linked immunosorbent assay (ELISA)-based analyses. 16HBE cells were utilized to explore the effect of QXT or hydrogen peroxide (H₂O₂) on the expression of E-cadherin in vitro.

Results

We found that QXT treatment increased E-cadherin expression and decreased extracellular-signal-regulated kinase (ERK) phosphorylation levels in the lung tissues of OVA-challenged mice. QXT also downregulated ROS levels and increased serum SOD and TAOC levels in OVA-challenged mice. In vitro studies demonstrated that increased ROS generation induced by H₂O₂ resulted in decreased E-cadherin expression levels in 16HBE cells, which was attenuated by inhibition of ERK signaling. Moreover, the H₂O₂-induced downregulation of E-cadherin expression, increased ROS generation, and ERK activation in 16HBE cells were restored by treatment with QXT water or ethanol extract.

Conclusions

These data demonstrate that one mechanism by which QXT protects against asthma is to restore E-cadherin expression in vivo and in vitro by inhibiting ROS-mediated ERK activation.

Cigarette Smoke Extract Stimulates MMP-2 Production in Nasal Fibroblasts via ROS/PI3K, Akt, and NF-κB Signaling Pathways

Cigarette smoke exposure has been shown to be associated with chronic rhinosinusitis and tissue remodeling. The present study aimed to investigate the effects of cigarette smoke extract (CSE) on matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) production in nasal fibroblasts and to determine the underlying molecular mechanisms. Primary nasal fibroblasts from six patients were isolated and cultured. After the exposure of fibroblasts to CSE, the expression levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured by real-time PCR, ELISA, and immunofluorescence staining. The enzymatic activities of MMP-2 and MMP-9 were measured by gelatin zymography. Reactive oxygen species (ROS) production was analyzed using dichloro-dihydro-fluorescein diacetate and Amplex Red assays. PI3K/Akt phosphorylation and NF-κB activation were determined by Western blotting and luciferase assay. CSE significantly increased MMP-2 expression and inhibited TIMP-2 expression but did not affect MMP-9 and TIMP-1 expression. Furthermore, CSE significantly induced ROS production. However, treatment with ROS scavengers, specific PI3K/Akt inhibitors, NF-κB inhibitor, and glucocorticosteroids significantly decreased MMP-2 expression and increased TIMP-2 expression. Our results suggest that steroids inhibit CSE-regulated MMP-2 and TIMP-2 production and activation through the ROS/ PI3K, Akt, and NF-κB signaling pathways in nasal fibroblasts. CSE may contribute to the pathogenesis of chronic rhinosinusitis by regulating MMP-2 and TIMP-2 expression.

Ovarian Dysfunction Induced by Chronic Whole-Body PM2.5 Exposure

Fine particulate matter (PM2.5) pollution arouses public health concerns over the world. Increasing epidemiologic evidence suggests that exposure to ambient airborne PM2.5 increases the risk of female infertility. However, relatively few studies have systematically explored the harmful effect of chronic PM2.5 exposure on ovarian function and the underlying mechanisms. In this study, female C57BL/6J mice are exposed to filtered air or urban airborne PM2.5 for 4 months through a whole-body exposure system. It is found that PM2.5 exposure significantly caused the alteration of estrus cycles, reproductivity, hormone levels, and ovarian reserve. The granulosa cell apoptosis via the mitochondria dependent pathway contributes to the follicle atresia. With RNA-sequencing technique, the differentially expressed genes induced by PM2.5 exposure are mainly enriched in ovarian steroidogenesis, reactive oxygen species and oxidative phosphorylation pathways. Furthermore, it is found that increased PM2.5 profoundly exacerbated ovarian oxidative stress and inflammation in mice through the NF-κB/IL-6 signaling pathway. Notably, dietary polydatin (PD) supplement has protective effect in mice against PM2.5-induced ovarian dysfunction.These striking findings demonstrate that PM2.5 and/or air pollution is a critical factor for ovarian dysfunction through mitochondria-dependent and NF-κB/IL-6-mediated pathway, and PD may serve as a pharmaceutic candidate for air pollution-associated ovarian dysfunction.

Nrf2 and the Nrf2-Interacting Network in Respiratory Inflammation and Diseases

Atmospheric pollutants and cigarette smoke influence the human respiratory system and induce airway inflammation, injury, and pathogenesis. Activation of the NF-E2-related factor 2 (Nrf2) transcription factor and downstream antioxidant response element (ARE)-mediated transcriptions play a central role in protecting respiratory cells against reactive oxidative species (ROS) that are induced by airway toxins and inflammation. Recent studies have revealed that Nrf2 can also target and activate many genes involved in developmental programs such as cell proliferation, cell differentiation, cell death, and metabolism. Nrf2 is closely regulated by the interaction with kelch-like ECH-associated protein 1 (Keap1), while also directly interacts with a number of other proteins, including inflammatory factors, transcription factors, autophagy mediators, kinases, epigenetic modifiers, etc. It is believed that the multiple target genes and the complicated interacting network of Nrf2 account for the roles of Nrf2 in physiologies and pathogeneses. This chapter summarizes the molecular functions and protein interactions of Nrf2, as well as the roles of Nrf2 and the Nrf2-interacting network in respiratory inflammation and diseases, including acute lung injury (ALI), asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), cystic fibrosis (CF), viral/bacterial infections, and lung cancers. Therapeutic applications that target Nrf2 and its interacting proteins in respiratory diseases are also reviewed.

Parkin and Nrf2 prevent oxidative stress-induced apoptosis in intervertebral endplate chondrocytes via inducing mitophagy and anti-oxidant defenses

AIMS

Endplate chondrocyte apoptosis is an important contributor to the pathogenesis of cartilaginous endplate (CEP) degeneration that leads to the initiation and development of intervertebral disc degeneration (IDD). In this study, we hypothesized that Parkin-mediated mitophagy and nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant system played an important role in endplate chondrocyte survival under pathological conditions.

MATERIALS AND METHODS

Human endplate chondrocytes were stimulated with H₂O₂ to mimic pathological conditions. Western blotting, immunofluorescence staining, and flow cytometry were applied to detect the indicators related to mitochondrial dynamics, mitophagy, Nrf2 signaling, and apoptosis. The puncture-induced rat models were established to evaluate the changes in vivo.

KEY FINDINGS

Our results showed that H₂O₂ induced oxidative stress, mitochondrial dysfunction, and apoptosis in endplate chondrocytes. These H₂O₂-induced detrimental effects were inhibited by pretreatment with the mitochondria-targeted antioxidant Mito-TEMPO. In addition, mitochondrial dynamics, Parkin-mediated elimination of dysfunctional mitochondria, and Nrf2-mediated antioxidant system were promoted by H₂O₂. Knockdown of Parkin or Nrf2 increased H₂O₂-induced detrimental effects. Moreover, upregulation of Parkin and Nrf2 by polydatin protected endplate chondrocytes against H₂O₂-induced mitochondrial dysfunction, oxidative stress, and apoptosis. Finally, puncture-induced rat models showed that polydatin exerted a protective effect on CEP and disc degeneration.

SIGNIFICANCE

Targeting Parkin and Nrf2 to improve mitochondrial homeostasis, redox balance and endplate chondrocyte survival may represent a potential therapeutic strategy for preventing IDD.

BAFF gene silencing attenuates allergic airway inflammation by promoting the generation of Tregs via activating pro-Treg cytokines

AIMS

Allergic airway inflammation is one of the major pathological events involved in asthma, and dysregulation of regulatory T cells (Treg) plays a crucial role in the development of allergic airway inflammation. Here, we attempted to investigate the regulatory effects of B cell-activating factor (BAFF) on Tregs in allergic airway inflammation.

MAIN METHODS

BAFF expression was analyzed by ELISA, quantitative reverse transcription PCR (RT-PCR) and Western blot assays. The levels of IL-4, TGF-β, IL-2, and IL-10 were tested using ELISA kits. Flow cytometry was conducted to analyze the populations of CTLA4⁺ Foxp3⁺ Tregs.

KEY FINDINGS

BAFF was found to be aberrantly expressed in sputum and lungs in patients with asthma as well as OVA sensitized mice. BAFF silencing by lentiviral BAFF shRNA reduced the number of eosinophils and levels of IL-4 in the BAL fluid, as well as the Fizz1 expression in the lungs of OVA mice. Additionally, the population of CTLA4⁺ Foxp3⁺ Tregs were significantly decreased in OVA mice and had a negative correlation to BAFF levels in asthmatic patients and OVA mice. BAFF silencing in vivo increased levels of CTLA4⁺ Foxp3⁺ Tregs and the secretion of IL-10, and improved the regulatory phenotype and suppressor function of Tregs in vitro. Furthermore, BAFF can affect Tregs generation by regulating the production of the pro-Treg cytokines IL-2 and TGF-β.

SIGNIFICANCE

BAFF has an inhibitory effect on the generation and suppressor function of Tregs by affecting pro-Tregs cytokines, thereby contributing to the development of allergic airway inflammation.

Isosteroid alkaloids from Fritillaria cirrhosa bulbus as inhibitors of cigarette smoke-induced oxidative stress

Fritillaria cirrhosa bulbus is a Chinese folk herb famous for its antitussive, expectorant, anti-asthma and anti-inflammatory properties, and is widely used to treat respiratory diseases. However, the impacts of F. cirrhosa bulbus on oxidative stress are still unkown. In the present study, we investigated the potential effect and mechanism of six isosteroid alkaloids with different chemical structures from F. cirrhosa bulbus on protection against cigarette smoke-induced oxidative stress in RAW264.7 macrophages. The results showed that six isosteroid alkaloids reduced reactive oxygen species (ROS) production, elevated glutathione (GSH) level and promoted heme oxygenase (HO-1) expression, which is in association with induction of NF-E2-related factor 2 (Nrf2) nuclear translocation and up-regulation of Nrf2 expression. Among these alkaloids, verticinone, verticine, imperialine-3-β-D-glucoside, delavine and peimisine exhibited more potent effect against CSE-induced oxidative stress than that of imperialine. These findings for the first time demonstrated that F. cirrhosa bulbus may play a protective role in cellular oxidative stress by activating Nrf2-mediated antioxidant pathway. Furthermore, the differences in antioxidant effects of these alkaloids were compared, as well as the corresponding structure-activity relationships were preliminarily elucidated. This suggested that F. cirrhosa bulbus might be a promising therapeutic treatment for the prevent of oxidative stress-related diseases.

Hydrogen inhalation attenuated bleomycin-induced pulmonary fibrosis by inhibiting transforming growth factor-β1 and relevant oxidative stress and epithelial-to-mesenchymal transition

NEW FINDINGS

• What is the central question of this study? The aim was to explore the effects and underlying mechanisms of H₂ on bleomycin-induced pulmonary fibrosis. • What are the main findings and its importance? Our results indicate that, in bleomycin-induced pulmonary fibrosis, H₂ inhalation attenuated oxidative stress and reversed the pulmonary epithelial-to-mesenchymal transition process by reducing reactive oxygen species production and inhibiting the expression of transforming growth factor-β1, α-smooth muscle actin and collagen I to improve fibrotic injury and exert anti-fibrogenic effects. Thus, H₂ inhalation has promising therapeutic potential as a useful adjuvant treatment for patients with idiopathic pulmonary fibrosis, which deserves further study and evaluation.

ABSTRACT

Hydrogen (H₂ ) can protect against tissue damage. The effect of H₂ inhalation therapy on the pathogenesis of pulmonary fibrosis remains unknown. This study was designed to explore the effects and underlying mechanisms of H₂ inhalation on bleomycin (BLM)-induced pulmonary fibrosis. A rat model of pulmonary fibrosis was established with BLM. Rats were randomly divided into control and H₂ inhalation groups. Haematoxylin and Eosin staining and Mason's Trichrome staining were performed to evaluate pulmonary fibrosis injury, inflammatory cell infiltration, structural disorder and collagen deposition. qRT-PCR and western blot assays were used to determine the expression of TNF-α, TGF-β1, α-SMA, E-cadherin, N-cadherin, vimentin, VEGF and collagen type I at both mRNA and protein levels. The contents of reactive oxygen species, TGF-β1, TNF-α, malondialdehyde and hydroxyproline were determined with biochemical test kits or ELISA kits. Bleomycin-stimulated rats exhibited typical symptoms of pulmonary fibrosis, which featured an increase in collagen deposition, alveolitis, fibrosis and parenchymal structural disorder in the lung. However, BLM-induced oxidative stress was attenuated by H₂ inhalation therapy, which reduced the contents of reactive oxygen species, malondialdehyde and hydroxyproline, enhanced the activity of glutathione peroxidase and decreased the expression of TGF-β1 and TNF-α. In addition, H₂ inhalation also inhibited BLM-induced epithelial-to-mesenchymal transition by inhibiting TGF-β1, increasing the expression level of the epithelial cell marker E-cadherin, and decreasing the expression level of the mesenchymal cell marker vimentin in a time-dependent manner. In addition, H₂ inhalation downregulated α-SMA expression and suppressed collagen I generation, exerting anti-fibrogenic effects. Hydrogen inhalation therapy attenuates BLM-induced pulmonary fibrosis by inhibiting TGF-β1, relevant oxidative stress and epithelial-to-mesenchymal transition.

Targeting cell signaling in allergic asthma

Asthma is chronic inflammation of the airways characterized by airway hyper-responsiveness, wheezing, cough, and dyspnea. Asthma affects >350 million people worldwide. The Th2 immune response is a major contributor to the pathophysiology of asthma. Targeted therapy modulating cell signaling pathways can be a powerful strategy to design new drugs to treat asthma. The potential molecular pathways that can be targeted include IL-4-IL-13-JAK-STAT-MAP kinases, adiponectin-iNOS-NF-κB, PGD2-CRTH2, IFNs-RIG, Wnt/β-catenin-FAM13A, FOXC1-miR-PI3K/AKT, JNK-Gal-7, Nrf2-ROS, Foxp3-RORγt, CysLTR, AMP, Fas-FasL, PTHrP/PPARγ, PAI-1, FcɛRI-LAT-SLP-76, Tim-3-Gal-9, TLRs-MyD88, PAR2, and Keap1/Nrf2/ARE. Therapeutic drugs can be designed to target one or more of these pathways to treat asthma.

The Protective Effects of 2,3,5,4'-Tetrahydroxystilbene-2-O-β-d-Glucoside in the OVA-Induced Asthma Mice Model

Asthma is an inflammatory disease caused by an imbalance of Th1 and Th2 cells. In general, asthma is characterized by a stronger Th2 response. Most conventional asthma treatment focuses on improving airway flow or suppression of airway inflammation. To reduce the side effects of currently used asthma medicines, we have conducted studies on natural products that have no side effects. 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside (TSG), the main compound of Polygonum multiflorum (PM), has various biological activities, including anti-inflammation and anti-oxidation activities. However, the effect of TSG on asthma has not been studied yet. We examined the effects of TSG on Th2 immune responses using an OVA-induced asthma animal model. OVA-sensitized mice were treated with TSG. 24 h after the last intranasal challenge, airway hyperresponsiveness (AHR) was measured or serum and bronchoalveolar lavage fluid (BALF) were harvested. We measured typical Th1 and Th2 cytokines in serum and BALF. As a result, TSG suppressed Th2 responses, as shown by the lower levels of IL-4, IL-5, total IgE, OVA-specific IgE, and OVA-specific IgG1. On the other hand, TSG increased Th1 responses, as shown by the levels of IFN-gamma. Collectively, these results confirm the potential of TSG for asthma treatment through modulation of inflammatory responses. Considering that the cytotoxic effect of PM extract is due to the cis isomer of TSG, if the effect of TSG on asthma treatment is found to be non-toxic in clinical trials, it would be more effective to use it as a purified component than PM extract as an asthma treatment agent.