Resveratrol alleviates chronic "real-world" ambient particulate matter-induced lung inflammation and fibrosis by inhibiting NLRP3 inflammasome activation in mice

Air pollution exposure, chemical compositions, and risk of expiratory airflow limitation in youth in Northeast China

BACKGROUND

Expiratory airflow limitation (EAL) is closely associated with respiratory health in youth and adulthood. Owing to limited evidence, we aim to estimate the association between air pollutants, both individually and in combination, along with their chemical compositions, and the risk of EAL in youth based on data obtained from Northeast China Biobank.

METHODS

Pulmonary function was evaluated using a medical-grade pulmonary function analyzer, with EAL defined as a forced expiratory flow in 1 s/ forced vital capacity ratio of < 0.8. Land use regression models were used to predict exposure to six air pollutants. Air pollution score (APS) for each participant was constructed as combined exposure. The chemical composition of particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) was determined using a validated machine-learning algorithm. Logistic regression models were employed to estimate effect sizes, and odds ratio (OR) and 95 % confidence intervals (CI) were calculated.

RESULTS

In total, 905 EAL cases were identified among the 4301 participants, with a prevalence of 21.04 %. Each inter-quartile range increase in APS was associated with a 25 % higher risk of EAL (OR = 1.25, 95 % CI: 1.12, 1.39). Among the pollutants analyzed, PM2.5 exposure had the strongest association with the risk of EAL (OR = 1.33, 95 % CI: 1.18, 1.52). Out of the five chemical components, sulfate (SO2-4) (OR = 1.39, 95 % CI: 1.24, 1.57) and ammonium (NH+4) (OR = 1.39, 95 % CI: 1.23, 1.57) exhibited the strongest associations with the risk of EAL.

CONCLUSIONS

Overall, combined effects of air pollution increased the risk of EAL in youth, with SO2-4 and NH+4 emerging as the predominant contributing chemical components in Northeast China.

Molecular mechanisms underlying NLRP3 inflammasome activation and IL-1β production in air pollution fine particulate matter (PM2.5)-primed macrophages

Exposure to air pollution fine particulate matter (PM2.5) aggravates respiratory and cardiovascular diseases. It has been proposed that PM2.5 uptake by alveolar macrophages promotes local inflammation that ignites a systemic response, but precise underlying mechanisms remain unclear. Here, we demonstrate that PM2.5 phagocytosis leads to NLRP3 inflammasome activation and subsequent release of the pro-inflammatory master cytokine IL-1β. Inflammasome priming and assembly was time- and dose-dependent in inflammasome-reporter THP-1-ASC-GFP cells, and consistent across PM2.5 samples of variable chemical composition. While inflammasome activation was promoted by different PM2.5 surrogates, significant IL-1β release could only be observed after stimulation with transition-metal rich Residual Oil Fly Ash (ROFA) particles. This effect was confirmed in primary human monocyte-derived macrophages and murine bone marrow-derived macrophages (BMDMs), and by confocal imaging of inflammasome-reporter ASC-Citrine BMDMs. IL-1β release by ROFA was dependent on the NLRP3 inflammasome, as indicated by lack of IL-1β production in ROFA-exposed NLRP3-deficient (Nlrp3-/-) BMDMs, and by specific NLRP3 inhibition with the pharmacological compound MCC950. In addition, while ROFA promoted the upregulation of pro-inflammatory gene expression and cytokines release, MCC950 reduced TNF-α, IL-6, and CCL2 production. Furthermore, inhibition of TNF-α with a neutralizing antibody decreased IL-1β release in ROFA-exposed BMDMs. Using electron tomography, ROFA particles were observed inside intracellular vesicles and mitochondria, which showed signs of ultrastructural damage. Mechanistically, we identified lysosomal rupture, K+ efflux, and impaired mitochondrial function as important prerequisites for ROFA-mediated IL-1β release. Interestingly, specific inhibition of superoxide anion production (O2•-) from mitochondrial respiratory Complex I, but not III, blunted IL-1β release in ROFA-exposed BMDMs. Our findings unravel the mechanism by which PM2.5 promotes IL-1β release in macrophages and provide a novel link between innate immune response and exposure to air pollution PM2.5.

Quercetin alleviates PM2.5-induced chronic lung injury in mice by targeting ferroptosis

Background

PM2.5 is a well-known harmful air pollutant that can lead to acute exacerbation and aggravation of respiratory diseases. Although ferroptosis is involves in the pathological process of pulmonary disease, the potential mechanism of ferroptosis in PM2.5-caused lung inflammation and fibrosis need to be further clarified. Quercetin is a phenolic compound that can inhibit ferroptosis in various diseases. Hence, this study explores the role of ferroptosis in lung injury induced by PM2.5 in order to further elucidate the beneficial effect of quercetin and its underlying mechanism.

Methods

C57BL/6J mice were treated with either saline or PM2.5 by intratracheal instillation 20 times (once every two days). Additionally, PM2.5-treated mice were supplemented with two doses of quercetin. Lung injury, lipid peroxidation, iron content and ferroptosis marker protein expression and the Nrf2 signaling pathway were evaluated. In vitro, cell experiments were applied to verify the mechanisms underlying the links between Nrf2 signaling pathway activation and ferroptosis as well as between ferroptosis and inflammation.

Results

In vivo, PM2.5 increased lung inflammation and caused lung fibrosis and increased lipid peroxidation contents, iron contents and ferroptosis markers in lung tissues; these effects were significantly reversed by quercetin. Additionally, quercetin upregulated the nuclear Nrf2 expression and downregulated Keap1 expression in lung tissues of PM2.5-exposed mice. Quercetin decreased lipid peroxidation products, iron contents and ferroptosis levels and increased the nuclear translocation of Nrf2 and the degradation of Keap1 in PM2.5-exposed BEAS-2B cells. Moreover, we found that quercetin and dimethyl fumarate markedly decreased lipid peroxidation production and ferroptosis by activating the Nrf2-Keap1 pathway in PM2.5-exposed cells. Furthermore, quercetin reduced inflammatory cytokines and TGF-β1 in PM2.5-exposed cells.

Conclusion

Our data suggested that Nrf2 is involved in ferroptosis in PM2.5-induced lung injury, and quercetin can alleviate these adverse effects via activating Nrf2-Keap1 signaling pathway.

Promotion of myofibroblast differentiation through repeated treatment of fibroblasts to low concentrations of PM2.5

Exposure to particulate matter ≤ 2.5 µm (PM2.5) is a risk factor for many lung diseases. Although the toxicologic effects of PM2.5 on airway epithelium are well-described, the effects of PM2.5 on fibroblasts in the lung are less studied. Here, we sought to examine the effects of PM2.5 on the differentiation of fibroblasts into myofibroblasts. Although a single treatment of fibroblasts did not result in a change in collagen or the myofibroblast marker α-SMA, exposing fibroblasts to sequential treatments with PM2.5 at low concentrations caused a robust increase in these proteins. Treatment of fibroblasts with IMD0354, an inhibitor to nuclear factor κB, but not with an antagonist to aryl hydrocarbon receptor, abolished the ability of PM2.5 to induce myofibroblast differentiation. These data demonstrate that potential impact of PM2.5 to fibroblast activation and fibrosis and support the importance of utilizing low concentrations and varying exposure protocols to toxicologic studies.

Environmental pollutants induce NLRP3 inflammasome activation and pyroptosis: Roles and mechanisms in various diseases

Environmental pollution is changing with economic development. Most environmental pollutants are characterized by stable chemical properties, strong migration, potential toxicity, and multiple exposure routes. Harmful substances are discharged excessively, and large quantities of unknown new compounds are emerging, being transmitted and amplifying in the food chain. The increasingly severe problems of environmental pollution have forced people to re-examine the relationship between environmental pollution and health. Pyroptosis and activation of the NLRP3 inflammasome are critical in maintaining the immune balance and regulating the inflammatory process. Numerous diseases caused by environmental pollutants are closely related to NLRP3 inflammasome activation and pyroptosis. We intend to systematically explain the steps and important events that are common in life but easily overlooked by which environmental pollutants activate the NLRP3 inflammasome and pyroptosis pathways. This comprehensive review also discusses the interaction network between environmental pollutants, the NLRP3 inflammasome, pyroptosis, and diseases. Thus, research progress on the impact of decreasing oxidative stress levels to inhibit the NLRP3 inflammasome and pyroptosis, thereby repairing homeostasis and reshaping health, is systematically examined. This review aims to deepen the understanding of the impact of environmental pollutants on life and health and provide a theoretical basis and potential programs for the development of corresponding treatment strategies.

TRPA1: A promising target for pulmonary fibrosis?

Pulmonary fibrosis is a disease characterized by progressive scar formation and the ultimate manifestation of numerous lung diseases. It is known as "cancer that is not cancer" and has attracted widespread attention. However, its formation process is very complex, and the mechanism of occurrence has not been fully elucidated. Current research has found that TRPA1 may be a promising target in the pathogenesis of pulmonary fibrosis. The TRPA1 channel was first successfully isolated in human lung fibroblasts, and it was found to have a relatively concentrated distribution in the lungs and respiratory tract. It is also involved in various acute and chronic inflammatory processes of lung diseases and may even play a core role in the progression and/or prevention of pulmonary fibrosis. Natural ligands targeting TRPA1 could offer a promising alternative treatment for pulmonary diseases. Therefore, this review delves into the current understanding of pulmonary fibrogenesis, analyzes TRPA1 biological properties and regulation of lung disease with a focus on pulmonary fibrosis, summarizes the TRPA1 molecular structure and its biological function, and summarizes TRPA1 natural ligand sources, anti-pulmonary fibrosis activity and potential mechanisms. The aim is to decipher the exact role of TRPA1 channels in the pathophysiology of pulmonary fibrosis and to consider their potential in the development of new therapeutic strategies.

Korean Red Ginseng Prevents the Deterioration of Lung and Brain Function in Chronic PM2.5-Exposed Mice by Regulating Systemic Inflammation

This study was conducted to confirm the effects of Korean red ginseng on lung and brain dysfunction in a BALB/c mice model exposed to particulate matter (PM)2.5 for 12 weeks. Learning and cognitive abilities were assessed with Y-maze, passive avoidance, and Morris water maze tests. To evaluate the ameliorating effect of red ginseng extract (RGE), the antioxidant system and mitochondrial function were investigated. The administration of RGE protected lung and brain impairment by regulating the antioxidant system and mitochondrial functions damaged by PM2.5-induced toxicity. Moreover, RGE prevented pulmonary fibrosis by regulating the transforming growth factor beta 1 (TGF-β1) pathway. RGE attenuated PM2.5-induced pulmonary and cognitive dysfunction by regulating systemic inflammation and apoptosis via the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/c-Jun N-terminal kinases (JNK) pathway. In conclusion, RGE might be a potential material that can regulate chronic PM2.5-induced lung and brain cognitive dysfunction.

A systematic review of the research progress of traditional Chinese medicine against pulmonary fibrosis: from a pharmacological perspective

Pulmonary fibrosis is a chronic progressive interstitial lung disease caused by a variety of etiologies. The disease can eventually lead to irreversible damage to the lung tissue structure, severely affecting respiratory function and posing a serious threat to human health. Currently, glucocorticoids and immunosuppressants are the main drugs used in the clinical treatment of pulmonary fibrosis, but their efficacy is limited and they can cause serious adverse effects. Traditional Chinese medicines have important research value and potential for clinical application in anti-pulmonary fibrosis. In recent years, more and more scientific researches have been conducted on the use of traditional Chinese medicine to improve or reduce pulmonary fibrosis, and some important breakthroughs have been made. This review paper systematically summarized the research progress of pharmacological mechanism of traditional Chinese medicines and their active compounds in improving or reducing pulmonary fibrosis. We conducted a systematic search in several main scientific databases, including PubMed, Web of Science, and Google Scholar, using keywords such as idiopathic pulmonary fibrosis, pulmonary fibrosis, interstitial pneumonia, natural products, herbal medicine, and therapeutic methods. Ultimately, 252 articles were included and systematically evaluated in this analysis. The anti-fibrotic mechanisms of these traditional Chinese medicine studies can be roughly categorized into 5 main aspects, including inhibition of epithelial-mesenchymal transition, anti-inflammatory and antioxidant effects, improvement of extracellular matrix deposition, mediation of apoptosis and autophagy, and inhibition of endoplasmic reticulum stress. The purpose of this article is to provide pharmaceutical researchers with information on the progress of scientific research on improving or reducing Pulmonary fibrosis with traditional Chinese medicine, and to provide reference for further pharmacological research.

Customizable Resveratrol Spray-dried Micro-composites for Inhalation as a Promising Contender for Treatment of Idiopathic Pulmonary Fibrosis

The past decades have witnessed tremendous expansion in utilization of plant-derived medicines as resveratrol (RES) in treating several diseases like idiopathic pulmonary fibrosis (IPF). RES can exhibit its role in treating IPF via its outstanding antioxidant and anti-inflammatory activities. The goal of this work was to formulate RES-loaded spray-dried composite microparticles (SDCMs) suitable for pulmonary delivery via dry powder inhaler (DPI). They were prepared by spray drying of a previously prepared RES-loaded bovine serum albumin nanoparticles (BSA NPs) dispersion using different carriers. RES-loaded BSA NPs, prepared by the desolvation technique, acquired suitable particle size of 177.67±0.95 nm and entrapment efficiency of 98.7±0.35% with perfectly uniform size distribution and high stability. Considering the attributes of the pulmonary route, NPs were co-spray dried with compatible carriers viz. mannitol, dextran, trehalose, leucine, glycine, aspartic acid, and glutamic acid to fabricate SDCMs. All formulations showed suitable mass median aerodynamic diameter less than 5 µm; that is suitable for deep lung deposition. However, the best aerosolization behavior was attained from using leucine with fine particle fraction (FPF) of 75.74%, followed by glycine with FPF of 54.7%. Finally, a pharmacodynamic study was conducted on bleomycin-induced mice, and it strongly revealed the role of the optimized formulations in alleviating PF through suppressing the levels of hydroxyproline, tumor necrosis factor-α and matrix metalloproteinase-9 with obvious improvements in the treated lung histopathology. These findings indicate that in addition to leucine, the glycine amino acid, which is not commonly used yet, is very promising in the formulation of DPIs.

Site-specific Atg13 methylation-mediated autophagy regulates epithelial inflammation in PM2.5-induced pulmonary fibrosis

Fine particulate matters (PM2.5) increased the risk of pulmonary fibrosis. However, the regulatory mechanisms of lung epithelium in pulmonary fibrosis remained elusive. Here we developed PM2.5-exposure lung epithelial cells and mice models to investigate the role of autophagy in lung epithelia mediating inflammation and pulmonary fibrosis. PM2.5 exposure induced autophagy in lung epithelial cells and then drove pulmonary fibrosis by activation of NF-κB/NLRP3 signaling pathway. PM2.5-downregulated ALKBH5 protein expression promotes m6A modification of Atg13 mRNA at site 767 in lung epithelial cells. Atg13-mediated ULK complex positively regulated autophagy and inflammation in epithelial cells with PM2.5 treatment. Knockout of ALKBH5 in mice further accelerated ULK complex-regulated autophagy, inflammation and pulmonary fibrosis. Thus, our results highlighted that site-specific m6A methylation on Atg13 mRNA regulated epithelial inflammation-driven pulmonary fibrosis in an autophagy-dependent manner upon PM2.5 exposure, and it provided target intervention strategies towards PM2.5-induced pulmonary fibrosis.

Coelonin protects against PM2 .5 -induced macrophage damage via suppressing TLR4/NF-κB/COX-2 signaling pathway and NLRP3 inflammasome activation in vitro

One of the important monitoring indicators of the air pollution is atmospheric fine particulate matter (PM_2.5 ), which can induce lung inflammation after inhalation. Coelonin can alleviate PM_2.5 -induced macrophage damage through anti-inflammation. However, its molecular mechanism remains unclear. We hypothesized that macrophage damage may involve the release of inflammatory cytokines, activation of inflammatory pathways, and pyrosis induced by inflammasome. In this study, we evaluated the anti-inflammation activity of coelonin in PM_2.5 -induced macrophage and its mechanism of action. Nitric oxide (NO) and reactive oxygen species (ROS) production were measured by NO Assay kit and dichlorofluorescein-diacetate (DCFH-DA), and apoptosis were measured by Flow cytometry and TUNEL staining. The concentration of inflammatory cytokines production was measured with cytometric bead arrays and ELISA kits. The activation of NF-κB signaling pathway and NLRP3 inflammasome were measured by immunofluorescence, quantitative reverse transcription-polymerase chain reaction and western blot. As expected, coelonin pretreatment reduced NO production significantly as well as alleviated cell damage by decreasing ROS and apoptosis. It decreased generation of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in PM_2.5 -induced RAW264.7 and J774A.1 cells. Moreover, coelonin markedly inhibited upregulating the expression of toll-like receptor (TLR)4 and cyclo-oxygenase (COX)-2, blocked activation of p-nuclear factor-kappa B (NF-κB) signaling pathway, and suppressed expression of NLRP3 inflammasome, ASC, GSDMD, IL-18 and IL-1β. In conclusion, the results showed that coelonin could protect against PM_2.5 -induced macrophage damage via suppressing TLR4/NF-κB/COX-2 signaling pathway and NLRP3 inflammasome activation in vitro.

Ambient particulate matter exposure plus chronic ethanol ingestion exacerbates hepatic fibrosis by triggering the mitochondrial ROS-ferroptosis signaling pathway in mice

BACKGROUND

Chronic ethanol ingestion causes persistent oxidative stresses in the liver, leading to hepatic injury and fibrosis, but the underlying mechanisms remain unclear. Recently, ambient particulate matter (PM) has been confirmed to aggravate high-fat diet-induced liver fibrosis by enhancing oxidative stress. Thus, we hypothesized that oxidative stress induced by ambient PM exposure increases the severity of liver fibrosis caused by ethanol ingestion.

METHODS AND RESULTS

C57BL/6 mice were subjected to ambient PM inhalation, ethanol ingestion or ambient PM-plus-ethanol ingestion for 12 weeks. Oxidative stress, mitochondrial reactive oxygen species (MtROS), liver fibrosis and ferroptosis indicators in the liver were evaluated. In vitro, oxidative stress, MtROS, ferroptosis indicators, profibrotic molecules and fibrosis markers in hepatic stellate (LX-2) cells were also determined. We found that ethanol ingestion markedly elevated hepatic oxidative stress and MtROS levels, triggered hepatic ferroptosis, and induced liver fibrosis, along with upregulation of the profibrotic molecule TGF-β1 and fibrosis marker collagen-I, in mice. Moreover, the combination of ambient PM and ethanol accelerated these adverse effects. Importantly, the combination of PM exposure and ethanol ingestion had a synergistic effect on these changes. In vitro, LX-2 cells activated with PM_2.5 alone or combined with ethanol showed upregulation of TGF-β1 and collagen-I. In addition, the levels of MtROS, the oxidative stress marker 4-hydroxynonenal (4-HNE) and ferroptosis-related proteins and the GSH/GSSG ratio were significantly increased in PM_2.5 plus ethanol-treated LX-2 cells. After pretreatment with a MtROS scavenger (Mito-TEMPO), we found that Mito-TEMPO treatment inhibited ferroptosis and oxidative stress in PM_2.5 plus ethanol-treated LX-2 cells. Furthermore, a specific ferroptosis inhibitor (Fer-1) decreased the levels of ferroptosis-related proteins and profibrotic molecules in activated LX-2 cells co-exposed to PM_2.5 and ethanol.

CONCLUSION

In this study, we revealed that ambient PM exposure induced profibrotic effects and that combined exposure to ambient PM and chronic ethanol ingestion exacerbated hepatic fibrosis, which may trigger ferroptosis by increasing MtROS, thereby activating hepatic stellate cells.

Potential of resveratrol in the treatment of interstitial lung disease

Interstitial lung disease (ILD) is a heterogeneous group of diseases characterized by lung injury caused by lung fibroblast proliferation, interstitial inflammation, and fibrosis. Different cell signal transduction pathways are activated in response to various proinflammatory or fibrotic cytokines, such as IL-6, and these cytokines are increased in different ILDs. The overexpressed cytokines and growth factors in ILD can activate TGF-β/Smad2/3/4, NF-κB, and JAK/STAT signal transduction pathways, promote the activation of immune cells, increase the release of pro-inflammatory and pro-fibrotic factors, differentiate fibroblasts into myofibroblasts, and promote the occurrence and development of ILD. This finding suggests the importance of signal transduction pathways in patients with ILD. Recent evidence suggests that resveratrol (RSV) attenuates excessive inflammation and pulmonary fibrosis by inhibiting the TGF-β/Smad2/3/4, NF-κB, and JAK/STAT signal transduction pathways and overactivation of immune cells. In this review, advances in lung protection and the underlying mechanisms of RSV are summarized, and the potential efficacy of RSV as a promising treatment option for ILD is highlighted.

Suppressing NLRP3 activation and PI3K/AKT/mTOR signaling ameliorates amiodarone-induced pulmonary fibrosis in rats: a possible protective role of nobiletin

Amiodarone (AMD), a medicine used to treat life-threatening arrhythmias, is frequently linked to pulmonary fibrosis (PF). Despite the involvement of NLRP3 inflammasome and PI3K/Akt/mTOR axis in fibrosis modulation and development, their significance in the etiology of AMD-induced PF remains uncertain. Nobiletin (NOB), a citrus flavonoid, has recently gained attention for its ability to reduce fibrotic processes in a variety of organs through inhibiting NLRP3-associated inflammation and suppressing PI3K/AKT/mTOR fibrotic pathway. Therefore, this research aimed to investigate the possible beneficial impact of NOB against AMD-induced PF, taking into account the roles of NLRP3 and PI3K/AKT/mTOR axis in its pathogenesis. Twenty-four rats were randomly specified into Vehicle; NOB 20 mg/kg; AMD 30 mg/kg, and NOB + AMD. All treatments were administered orally once a day for 4 weeks. The lung oxidant/antioxidant status, as well as the expression of inflammatory and fibrotic markers were all assessed. The results revealed that NOB, by improving Nrf2/HO-1 pathway, could reduce ROS production and NLRP3 activation, which in turn hindered IL-1β release, prohibited TGF-β1-related PI3K/AKT/mTOR cascade, suppressed α-SMA expression, and impeded collagen deposition. These findings point to a novel strategy by which NOB may alleviate the AMD-prompted NLRP3 inflammatory responses and associated PF through blocking PI3K/AKT/mTOR signaling.

Sipeimine attenuates PM2.5-induced lung toxicity via suppression of NLRP3 inflammasome-mediated pyroptosis through activation of the PI3K/AKT pathway

Exposure to fine particulate matter (PM2.5), an environmental pollutant, significantly contributes to the incidence of and risk of mortality associated with respiratory diseases. Sipeimine (Sip) is a steroidal alkaloid in fritillaries that exerts antioxidative and anti-inflammatory effects. However, protective effect of Sip for lung toxicity and its mechanism to date remains poorly understood. In the present study, we investigated the lung-protective effect of Sip via establishing the lung toxicity model of rats with orotracheal instillation of PM2.5 (7.5 mg/kg) suspension. Sprague-Dawley rats were intraperitoneally administered with Sip (15 mg/kg or 30 mg/kg) or vehicle daily for 3 days before instillation of PM2.5 suspension to establish the model of lung toxicity. The results found that Sip significantly improved pathological damage of lung tissue, mitigated inflammatory response, and inhibited lung tissue pyroptosis. We also found that PM2.5 activated the NLRP3 inflammasome as evidenced by the upregulation levels of NLRP3, cleaved-caspase-1, and ASC proteins. Importantly, PM2.5 could trigger pyroptosis by increased levels of pyroptosis-related proteins, including IL-1β, cleaved IL-1β, and GSDMD-N, membrane pore formation, and mitochondrial swelling. As expected, all these deleterious alterations were reversed by Sip pretreatment. These effects of Sip were blocked by the NLRP3 activator nigericin. Moreover, network pharmacology analysis showed that Sip may function via the PI3K/AKT signaling pathway and animal experiment validate the results, which revealed that Sip inhibited NLRP3 inflammasome-mediated pyroptosis by suppressing the phosphorylation of PI3K and AKT. Our findings demonstrated that Sip inhibited NLRP3-mediated cell pyroptosis through activation of the PI3K/AKT pathway in PM2.5-induced lung toxicity, which has a promising application value and development prospect against lung injury in the future.

Effectiveness of targeting the NLRP3 inflammasome by using natural polyphenols: A systematic review of implications on health effects

Globally, inflammation and metabolic disorders pose serious public health problems and are major health concerns. It has been shown that natural polyphenols are effective in the treatment of metabolic diseases, including anti-inflammation, anti-diabetes, anti-obesity, neuron-protection, and cardio-protection. NLRP3 inflammasome, which are multiprotein complexes located within the cytosol, play an important role in the innate immune system. However, aberrant activation of the NLRP3 inflammasome were discovered as essential molecular mechanisms in triggering inflammatory processes as well as implicating it in several major metabolic diseases, such as type 2 diabetes mellitus, obesity, atherosclerosis or cardiovascular disease. Recent studies indicate that natural polyphenols can inhibit NLRP3 inflammasome activation. In this review, the progress of natural polyphenols preventing inflammation and metabolic disorders via targeting NLRP3 inflammasome is systemically summarized. From the viewpoint of interfering NLRP3 inflammasome activation, the health effects of natural polyphenols are explained. Recent advances in other beneficial effects, clinical trials, and nano-delivery systems for targeting NLRP3 inflammasome are also reviewed. NLRP3 inflammasome is targeted by natural polyphenols to exert multiple health effects, which broadens the understanding of polyphenol mechanisms and provides valuable guidance to new researchers in this field.

Monomeric compounds from traditional Chinese medicine: New hopes for drug discovery in pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic and irreversible pulmonary disease, and can lead to decreased lung function, respiratory failure and even death. The pathogenesis research and treatment strategy of PF significantly lag behind the medical progress and clinical needs. The treatment of this disease remains a thorny clinical problem, and the effective therapeutic drugs are still limited. Monomeric compounds from traditional Chinese medicine own various biological activities and high safety. They play a broad part in treating diseases and is also a candidate drug for preventing and treating PF. In this paper, we reviewed the mechanism of action and potential value of various anti-PF monomeric compounds from traditional Chinese medicine. These monomeric compounds can attenuate inflammatory response, oxidative stress, epithelial mesenchymal transformation and other processes of lung through many signaling pathways, and inhibit the activation and differentiation of fibroblasts, thus contributing to the treatment of PF. This review can provide new ideas for the development of anti-PF drugs in high efficiency with low toxicity.

Resveratrol reversed ambient particulate matter exposure-perturbed oscillations of hepatic glucose metabolism by regulating SIRT1 in mice

Much evidence has shown that ambient particulate matter (PM) exposure is associated with abnormal glucose metabolism, but the underlying mechanism has not yet been fully characterized. Circadian disruption has adverse effects on glucose metabolism. In this study, we investigated the effects of long-term ambient PM exposure on the hepatic circadian clock and the expression rhythm of genes associated with hepatic glucose metabolism in mice. C57BL/6 mice were exposed to filtered air (FA), ambient PM, or ambient PM plus resveratrol (RES). After 15 weeks (12 h per day, 7 days per week) of exposure, glucose homeostasis, the rhythmic expression of clock genes, and genes associated with hepatic glucose metabolism were determined. Our results found that PM exposure induced glucose metabolism disorder and perturbed the rhythmic mRNA expression of core clock genes and their target genes involved in hepatic glucose metabolism. Mechanistic investigations demonstrated that ambient PM exposure markedly altered the expression patterns of BMAL1, clock, and SIRT1 in vivo. Simultaneously, we demonstrated that RES (an activator of SIRT1) changed the expression pattern of SIRT1, thereby reversing the rhythm misalignment of BMAL1 and clock and hepatic glucose metabolism disorder induced by ambient PM exposure. In addition, PM_2.5 exposure perturbed the rhythmic protein expression of BMAL1, clock, and SIRT1 in L-02 cells. Simultaneously, we demonstrated that RES restored the SIRT1 circadian rhythm, which reversed the rhythm misalignment of BMAL1 and clock in L-02 cells induced by PM_2.5 exposure. Taken together, our results suggested that long-term ambient PM exposure perturbed the hepatic core circadian clock rhythm and caused glucose metabolism disorder, which could be reversed by RES supplementation. Our study offers a potential application of RES for combating circadian misalignment-related metabolic diseases.

On the Need for Human Studies of PM Exposure Activation of the NLRP3 Inflammasome

Particulate matter air pollution is associated with blood inflammatory biomarkers, however, the biological pathways from exposure to periferal inflammation are not well understood. We propose that the NLRP3 inflammasome is likely stimulated by ambient particulate matter, as it is by some other particles and call for more research into this pathway.

Focusing on the hypoxia-inducible factor pathway: role, regulation, and therapy for osteoarthritis

Osteoarthritis (OA) is a common chronic disabling disease that affects hundreds of millions of people around the world. The most important pathological feature is the rupture and loss of articular cartilage, and the characteristics of avascular joint tissues lead to limited repair ability. Currently, there is no effective treatment to prevent cartilage degeneration. Studies on the mechanism of cartilage metabolism revealed that hypoxia-inducible factors (HIFs) are key regulatory genes that maintain the balance of cartilage catabolism-matrix anabolism and are considered to be the major OA regulator and promising OA treatment target. Although the exact mechanism of HIFs in OA needs to be further clarified, many drugs that directly or indirectly act on HIF signaling pathways have been confirmed by animal experiments and regarded as promising treatments for OA. Targeting HIFs will provide a promising strategy for the development of new OA drugs. This article reviews the regulation of HIFs on intra-articular cartilage homeostasis and its influence on the progression of osteoarthritis and summarizes the recent advances in OA therapies targeting the HIF system.

Mechanisms of cell injury induced by inhaled molybdenum trioxide nanoparticles in Golden Syrian Hamsters

Molybdenum trioxide nanoparticles (MoO₃ NPs) are extensively used in the biomedical, agricultural, and engineering fields that may increase exposure and adverse health effects to the human population. The purpose of this study is to evaluate a possible molecular mechanism leading to cell damage and death following pulmonary exposure to inhaled MoO₃ NPs. Animals were separated into four groups: two control groups exposed to room air or aerosolized water and two treated groups exposed to aerosolized MoO₃ NPs with a concentration of 5 mg/m³ NPs (4 h/day for eight days) and given a one-day (T-1) or seven-day (T-7) recovery period post exposure. Pulmonary toxicity was evaluated with total and differential cell counts. Increases were seen in total cell numbers, neutrophils, and multinucleated macrophages in the T-1 group, with increases in lymphocytes in the T-7 group (*P < 0.05). To evaluate the mechanism of toxicity, protein levels of Beclin-1, light chain 3 (LC3)-I/II, P-62, cathepsin B, NLRP3, ASC, caspase-1, interleukin (IL)-1β, and tumor necrosis factor-α (TNF-α) were assessed in lung tissue. Immunoblot analyses indicated 1.4- and 1.8-fold increases in Beclin-1 in treated groups (T-1 and T-7, respectively, *P < 0.05), but no change in protein levels of LC3-I/II in either treated group. The levels of cathepsin B were 2.8- and 2.3-fold higher in treated lungs (T-1 and T-7, respectively, *P < 0.05), the levels of NLRP3 had a fold increase of 2.5 and 3.6 (T-1 *P < 0.05, T-7 **P < 0.01, respectively), and the levels of caspase-1 indicated a 3.8- and 3.0-fold increase in treated lungs (T-1 and T-7, respectively, *P < 0.05). Morphological changes were studied using light and electron microscopy showing alterations to airway epithelium and the alveoli, along with particle internalization in macrophages. The results from this study may indicate that inhalation exposure to MoO₃ NPs may interrupt the autophagic flux and induce cytotoxicity and lung injury through pyroptosis cell death and activation of caspase-1.

Histopathological, physiological and biochemical assessment of resveratrol nanocapsules efficacy in bleomycin-induced acute and chronic lung injury in rats

Acute lung injury (ALI) is a life-threatening illness which may progress to chronic pulmonary fibrosis (CPF). Resveratrol (RSV), a natural polyphenol, is known to exert several pharmacological effects on lung injury. However, its physicochemical properties and pharmacokinetic profile limit its clinical applications. In this study, RSV was loaded into lipid nanocapsules (LNCs) aiming to overcome these limitations. RSV-LNCs were prepared by phase inversion method and showed small uniform particle size (∼55 nm, PdI 0.04) with high entrapment efficiency >99%. The efficacy of RSV-LNCs in the prophylaxis against ALI and treatment of CPF was investigated in bleomycin-induced lung injury. For assessment of ALI, rats were administered a single oral dose of RSV (10 mg/kg) either free or as RSV-LNCs 4 h before bleomycin and euthanized 3 days later. For CPF, treatments in the same dose were given daily from days 10–20 after bleomycin and rats were euthanized on day-21. Results showed enhanced beneficial role for RSV-LNCs, compared to RSV, in the prevention of ALI as demonstrated by preservation of pulmonary microscopic and ultrastructural architecture and improvement of pulmonary functions. Analysis of BALF revealed reduction in oxidative stress markers, IL-6 level, leukocytosis and neutrophilia. iNOS and c-caspase 3 immunohistochemical expression and CD68⁺ cells immunofluorescence were inhibited. However, RSV-LNCs failed to show any improvement in oxidative stress, chronic inflammation, apoptosis and collagen deposition in CPF. In conclusion, RSV-LNCs are promising nanoplatforms for mitigating ALI detrimental effects. Future research investigating higher doses and longer durations of treatment is recommended to evaluate RSV-LNCs anti-fibrotic potential in CPF.

A comprehensive understanding of ambient particulate matter and its components on the adverse health effects based from epidemiological and laboratory evidence

The impacts of air pollution on public health have become a great concern worldwide. Ambient particulate matter (PM) is a major air pollution that comprises a heterogeneous mixture of different particle sizes and chemical components. The chemical composition and physicochemical properties of PM change with space and time, which may cause different impairments. However, the mechanisms of the adverse effects of PM on various systems have not been fully elucidated and systematically integrated. The Adverse Outcome Pathway (AOP) framework was used to comprehensively illustrate the molecular mechanism of adverse effects of PM and its components, so as to clarify the causal mechanistic relationships of PM-triggered toxicity on various systems. The main conclusions and new insights of the correlation between public health and PM were discussed, especially at low concentrations, which points out the direction for further research in the future. With the deepening of the study on its toxicity mechanism, it was found that PM can still induce adverse health effects with low-dose exposure. And the recommended Air Quality Guideline level of PM_2.5 was adjusted to 5 μg/m³ by World Health Organization, which meant that deeper and more complex mechanisms needed to be explored. Traditionally, oxidative stress, inflammation, autophagy and apoptosis were considered the main mechanisms of harmful effects of PM. However, recent studies have identified several emerging mechanisms involved in the toxicity of PM, including pyroptosis, ferroptosis and epigenetic modifications. This review summarized the comprehensive evidence on the health effects of PM and the chemical components of it, as well as the combined toxicity of PM with other air pollutants. Based on the AOP Wiki and the mechanisms of PM-induced toxicity at different levels, we first constructed the PM-related AOP frameworks on various systems.

Demystifying phytoconstituent-derived nanomedicines in their immunoregulatory and therapeutic roles in inflammatory diseases

In the past decades, phytoconstituents have appeared as critical mediators for immune regulations among various diseases, both in eukaryotes and prokaryotes. These bioactive molecules, showing a broad range of biological functions, would hold tremendous promise for developing new therapeutics. The discovery of phytoconstituents' capability of functionally regulating immune cells and associating cytokines, suppressing systemic inflammation, and remodeling immunity have rapidly promoted the idea of their employment as anti-inflammatory agents. In this review, we discuss various roles of phyto-derived medicines in the field of inflammatory diseases, including chronic inflammation, autoimmune diseases, and acute inflammatory disease such as COVID-19. Nevertheless, traditional phyto-derived medicines often concurred with their clinical administration limitations, such as their lack of cell specificity, inefficient cytoplasmic delivery, and rapid clearance by the immune system. As alternatives, phyto-derived nano-approaches may provide significant benefits. Both unmodified and engineered nanocarriers present the potential to serve as phytoconstituent delivery systems to improve therapeutic physio-chemical properties and pharmacokinetic profiles. Thus, the development of phytoconstituents' nano-delivery designs, their new and perspective approaches for therapeutical applications are elaborated herein.

Polyphenols, flavonoids and inflammasomes: the role of cigarette smoke in COPD

COPD is predicted to become the third leading cause of morbidity and mortality worldwide by 2030. Cigarette smoking (active or passive) is one of its chief causes, with about 20% of cigarette smokers developing COPD from cigarette smoke (CS)-induced irreversible damage and sustained inflammation of the airway epithelium. Inflammasome activation leads to the cleavage of pro-interleukin (IL)-1β and pro-IL-18, along with the release of pro-inflammatory cytokines via gasdermin D N-terminal fragment membrane pores, which further triggers acute phase pro-inflammatory responses and concurrent pyroptosis. There is currently intense interest in the role of nucleotide-binding oligomerisation domain-like receptor family, pyrin domain containing protein-3 inflammasomes in chronic inflammatory lung diseases such as COPD and their potential for therapeutic targeting. Phytochemicals including polyphenols and flavonoids have phyto-medicinal benefits in CS-COPD. Here, we review published articles from the last decade regarding the known associations between inflammasome-mediated responses and ameliorations in pre-clinical manifestations of CS-COPD via polyphenol and flavonoid treatment, with a focus on the underlying mechanistic insights. This article will potentially assist the development of drugs for the prevention and therapy of COPD, particularly in cigarette smokers.

This review compiles current investigations into the role of polyphenols/flavonoids in the alleviation of cigarette smoke-induced inflammasome; notably it provides a promising hit for rectifying the treatment of COPD.https://bit.ly/36OcUO9

Polyphenols from Chinese Herbal Medicine: Molecular Mechanisms and Therapeutic Targets in Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a highly confounding and fatal pathological process with finite treatment options. Multiple factors such as oxidative and immune/inflammation involve key pathological processes in chronic lung disease, and their intimate interactions mediate chronic lung damage, denudation of the alveolar epithelium, hyperproliferation of type II alveolar epithelial cells (AECIIs), proliferation and differentiation of fibroblasts, and the permeability of microvessels. We reviewed the classic mechanism of PF and highlighted a few emerging mechanisms for studying complex networks in lung disease pathology. Polyphenols, as a multi-target drug, has excellent potential in the treatment of pulmonary fibrosis. We then reviewed recent advances in discovering phenolic compounds from fruits, tea, and medical herbs with the bioactivities of simultaneously regulating multiple factors (e.g., oxidative stress, inflammation, autophagy, apoptosis, pyroptosis) for minimizing pulmonary fibrosis injury. These compounds include resveratrol, curcumin, salvianolic acid B, epigallocatechin-3-gallate, gallic acid, corilagin. Each phenolic compound can exert its anti-PF effect through various mechanisms, and the signaling pathways involved in different phenolic compounds are not the same. This review summarized the available evidence on phenolic compounds' effectiveness in pulmonary diseases and explored the molecular mechanisms and therapeutic targets of phenolic compounds from Chinese herbal medicine with the properties of inhibition of ongoing fibrogenesis and resolution of existing fibrosis.

Antifibrotic effect of AD-1 on lipopolysaccharide-mediated fibroblast injury in L929 cells and bleomycin-induced pulmonary fibrosis in mice

20(R)-25-methoxyl-dammarane-3β,12β,20-triol (25-OCH₃-PPD, AD-1) is a dammarane ginsenoside that is isolated from Panax notoginseng. The present study aimed to explore its anti-pulmonary fibrosis (PF) effect in vitro and in vivo. L929 cells were treated with 10 μg mL^-1 lipopolysaccharide (LPS) to establish a PF model in vitro and mice were administered with 3.5 mg kg^-1 bleomycin (BLM) by endotracheal intubation to establish a PF model in vivo for investigating the anti-PF effect and its potential mechanism. The results demonstrated that AD-1 reduced the injury, extracellular matrix (ECM) buildup and α-smooth muscle actin (α-SMA) protein expression levels of L929 induced by LPS. Oral administration of AD-1 downregulated the expression of interleukins (such as IL-1β, IL-6 and IL-18), increased the expression of superoxide dismutase (SOD) and glutathione (GSH), reduced the lung coefficient and the content of hydroxyproline (HYP), and mediated the Bax/Bcl-2 protein ratio and P-p53, β-catenin and SIRT3 expression in the lung tissue of mice. Furthermore, AD-1 inhibited the expression levels of TGF-β1, TIMP-1 and α-SMA and reduced inflammatory cell infiltration and collagen deposition in the lung tissue of PF mice. These results indicated that AD-1 could alleviate PF both in vitro and in vivo, and the underlying mechanism may be related to the decrease in ECM deposition and inflammation, the enhancement of antioxidant capacity, and the mediation of lung cell apoptosis and the TGF-β1/TIMP-1/α-SMA signaling pathway, which provide a theoretical basis for the rehabilitation treatment of PF.

Ambient particulate matter exposure plus a high-fat diet exacerbate renal injury by activating the NLRP3 inflammasome and TGF-β1/Smad2 signaling pathway in mice

BACKGROUND

Chronic kidney disease (CKD) is a public health problem of which the prevalence is increasing worldwide. Several studies have reported that ambient particulate matter (PM) causes kidney injury, which may be related to the risk of CKD. However, the underlying molecular mechanisms have not been fully clarified. In addition, whether a high-fat diet (HFD) could exacerbate ambient PM-induced nephrotoxicity has not been evaluated. This study aimed to investigate the combined effect of ambient PM and a HFD on renal injury.

METHODS AND RESULTS

Male C57BL/6 J mice were fed either a normal diet or a HFD and exposed to filtered air (FA) or particulate matter (PM) for 18 weeks. In the present study, we observed that renal function changed (serum blood urea nitrogen and serum creatinine), and exposure to PM and a HFD caused a synergistic effect on renal injury. Histopathological analysis showed that PM exposure induced renal fibrosis in mice, and combined exposure to PM and a HFD exacerbated these adverse effects. Moreover, ambient PM exposure activated the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome and increased the inflammatory response, as indicated by the increases in interleukin-1β, interleukin-6 and tumor necrosis factor-α in the serum and kidney, as well as the upregulation of specific renal fibrosis-related markers (transforming growth factor-β1 and p-Smad2) in the kidney tissues of mice. Furthermore, combined exposure to PM and a HFD augmented these changes in the kidney. In vitro, inhibition of the NLRP3 inflammasome by MCC950 (an inhibitor of NLRP3) reduced the levels of proinflammatory cytokines and the expression of transforming growth factor-β1 and p-Smad2 in HK-2 cells.

CONCLUSION

Taken together, our data indicated that PM exposure caused renal inflammation and induced profibrotic effects on the kidney, and combined exposure to ambient PM and a HFD exacerbated renal injury, which may involve activation of the NLRP3 inflammasome and the TGF-β1/Smad2 signaling pathway.

The Invasive Species Reynoutria japonica Houtt. as a Promising Natural Agent for Cardiovascular and Digestive System Illness

Polygoni Cuspidati Rhizoma et Radix, the dry roots and stems of Reynoutria japonica Houtt (called Huzhang, HZ in Chinese), is a traditional and popular chinese medicinal herb for thousands of years. As a widely used ethnomedicine in Asia including China, Japan, and Korea, HZ can invigorate the blood, cool heat, and resolve toxicity, which is commonly used in the treatment of favus, jaundice, scald, and constipation. However, HZ is now considered an invasive plant in the United States and many European countries. Therefore, in order to take advantage of HZ and solve the problem of biological invasion, scholars around the world have carried out abundant research studies on HZ. Until now, about 110 compounds have been isolated and identified from HZ, in which anthraquinones, stilbenes, and flavonoids would be the main bioactive ingredients for its pharmacological properties, such as microcirculation improvement, myocardial protective effects, endocrine regulation, anti-atherosclerotic activity, anti-oxidant activity, anti-tumor activity, anti-viral activity, and treatment of skin inflammation, burns, and scalds. HZ has a variety of active ingredients and broad pharmacological activities. It is widely used in health products, cosmetics, and even animal husbandry feed and has no obvious toxicity. Efforts should be made to develop more products such as effective drugs, health care products, cosmetics, and agricultural and animal husbandry products to benefit mankind.

The NLRP3 inflammasome in fibrosis and aging: The known unknowns

Aging-related diseases such as cancer, cardiovascular diseases, diabetes, and neurodegenerative diseases are often accompanied by fibrosis. The NLRP3 inflammasome triggers the inflammatory response and subsequently promotes fibrosis through pathogen-associated molecular patterns (PAMPs). In this review, we first introduce the general background and specific mechanism of NLRP3 in fibrosis. Second, we investigate the role of NLRP3 in fibrosis in different organs/tissues. Third, we discuss the relationship between NLRP3 and fibrosis during aging. In summary, this review describes the latest progress on the roles of NLRP3 in fibrosis and aging and reveals the possibility of NLRP3 as an antifibrotic and anti-aging treatment target.

Study on Lung Injury Caused by Fine Particulate Matter and Intervention Effect of Rhodiola wallichiana

Objective

The objective of this study was to observe the protective effect of Rhodiola wallichiana drops in a rat model of fine particulate matter (PM2.5) lung injury.

Methods

Forty male Wistar rats were randomly divided into blank control (NC), normal saline (NS), PM2.5-infected (PM), and Rhodiola wallichiana (RW) groups. Rats in the NC group were not provided any interventions, whereas those in the NS and PM groups were administered normal saline and PM2.5 suspension by trachea drip once a week for four weeks. Rats in the RW group were intraperitoneally administered Rhodiola wallichiana for 14 days and then administered PM2.5 suspension by trachea drip 7 days after drug delivery. The levels of inflammatory factors such as interleukin-6, interleukin-1β, and tumor necrosis factor-alpha and oxidative stress biomarkers such as 8-hydroxy-2′-deoxyguanosine, 4-hydroxynonenal, and protein carbonyl content were determined in the serum and bronchoalveolar lavage fluid by ELISA. The level of 4-hydroxynonenal in the lung was also determined using Western blotting and immunohistochemical staining.

Results

Levels of inflammatory factors and oxidative stress biomarkers were all increased in the PM group but decreased in the RW group. Western blotting revealed increased 4-hydroxynonenal levels in the PM group but decreased levels in the RW group. Immunohistochemical staining also provided similar results.

Conclusion

Rhodiola wallichiana could protect rats from inflammation and oxidative stress injury caused by PM2.5.

Food bioactives lowering risks of chronic diseases induced by fine particulate air pollution: a comprehensive review

Airborne particulate matter (PM) exerts huge negative impacts on human health worldwide, not only targeting the respiratory system but more importantly inducing and aggravating associated chronic diseases like asthma, lung cancer, atherosclerosis, diabetes mellitus and Alzheimer diseases. Food-derived bioactive compounds like vitamins, dietary polyphenols, omega-3 polyunsaturated fatty acids and sulforaphane are feasible alternative therapeutic approaches against PM-mediated potential health damages, drawing great attention in recent years. In this review, the association between PM exposure and risks of developing chronic diseases, and the detailed mechanisms underlying the detrimental effects of PM will be discussed. Subsequently, principal food-derived bioactive compounds, with emphasize on the preventative or protective effects against PM, along with potential mechanisms will be elucidated. This comprehensive review will discuss and present current research findings to reveal the nutritional intervention as a preventative or therapeutic strategy against ambient air pollution, thereby lowering the risk of developing chronic diseases.

Role of Pyroptosis in Respiratory Diseases and its Therapeutic Potential

Pyroptosis is an inflammatory type of regulated cell death that is dependent on inflammasome activation and downstream proteases such as caspase-1 or caspase 4/5/11. The main executors are gasdermins, which have an inherent pore-forming function on the membrane and release inflammatory cytokines, such as interleukin (IL)-1β, IL-18 and high mobility group box 1. Emerging evidence demonstrates that pyroptosis is involved in the pathogenesis of various pulmonary diseases. In this review, we mainly discuss the biological mechanisms of pyroptosis, explore the relationship between pyroptosis and respiratory diseases, and discuss emerging therapeutic strategies for respiratory diseases.

The TCM Preparation Feilike Mixture for the Treatment of Pneumonia: Network Analysis, Pharmacological Assessment and Silico Simulation

The Feilike mixture (FLKM) is a valid prescription that is frequently used to assist in the clinical treatment of pneumonia. However, the mechanisms of its effects remain unclear. First, through literature evaluation, it was preliminarily determined that FLKM improved clinical symptoms, regulated immune inflammation response and ameliorated pulmonary function. Then, via database search and literature mining, 759 targets of the 104 active compounds of FLKM were identified. The component-target (CT) network showed that the key active compositions were resveratrol, stigmasterol, beta-sitosterol, sesamin, and quercetin. 115 targets overlapped with pneumonia-related targets. The protein-protein interaction (PPI) network identified TNF, AKT1, IL6, JUN, VEGFA and MAPK3 as hub targets. KEGG analyses found that they were mainly enriched in immune related pathway. Next, in vivo experiment, we observed that FLKM ameliorated pathological injury of lung tissue and reduced neutrophil infiltration in rats with LPS-induced pneumonia. And FLKM decreased the concentration of TNF-α and IL-6 in BALF and downregulated the expression of p38MAPK, AKT and VEGFA in lung tissue. Finally, Molecular docking tests showed tight docking of these predicted targeted proteins with key active compounds. Molecular dynamics simulation was employed to assess stability and flexibility of receptor-ligand. Among them, AKT1- stigmasterol bound more stably, and their binding free energies were −47.91 ± 1.62 kcal/mol. This study revealed core compositions and targets for FLKM treating pneumonia and provided integrated pharmacological evidence to support its clinical efficacy.

Targeting Oxidative Stress as a Therapeutic Approach for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease characterized by an abnormal reepithelialisation, an excessive tissue remodelling and a progressive fibrosis within the alveolar wall that are not due to infection or cancer. Oxidative stress has been proposed as a key molecular process in pulmonary fibrosis development and different components of the redox system are altered in the cellular actors participating in lung fibrosis. To this respect, several activators of the antioxidant machinery and inhibitors of the oxidant species and pathways have been assayed in preclinical in vitro and in vivo models and in different clinical trials. This review discusses the role of oxidative stress in the development and progression of IPF and its underlying mechanisms as well as the evidence of oxidative stress in human IPF. Finally, we analyze the mechanism of action, the efficacy and the current status of different drugs developed to inhibit the oxidative stress as anti-fibrotic therapy in IPF.

Biomarkers for the adverse effects on respiratory system health associated with atmospheric particulate matter exposure

Large amounts of epidemiological evidence have confirmed the atmospheric particulate matter (PM_2.5) exposure was positively correlated with the morbidity and mortality of respiratory diseases. Nevertheless, its pathogenesis remains incompletely understood, probably resulting from the activation of oxidative stress, inflammation, altered genetic and epigenetic modifications in the lung upon PM_2.5 exposure. Currently, biomarker investigations have been widely used in epidemiological and toxicological studies, which may help in understanding the biologic mechanisms underlying PM_2.5-elicited adverse health outcomes. Here, the emerging biomarkers to indicate PM_2.5-respiratory system interactions were summarized, primarily related to oxidative stress (ROS, MDA, GSH, etc.), inflammation (Interleukins, FE_NO, CC16, etc.), DNA damage (8-OHdG, γH2AX, OGG1) and also epigenetic modulation (DNA methylation, histone modification, microRNAs). The identified biomarkers shed light on PM_2.5-elicited inflammation, fibrogenesis and carcinogenesis, thus may favor more precise interventions in public health. It is worth noting that some inconsistent findings may possibly relate to the inter-study differentials in the airborne PM_2.5 sample, exposure mode and targeted subjects, as well as methodological issues. Further research, particularly by -omics technique to identify novel, specific biomarkers, is warranted to illuminate the causal relationship between PM_2.5 pollution and deleterious lung outcomes.

Quercetin improves the adipose inflammatory response and insulin signaling to reduce "real-world" particulate matter-induced insulin resistance

Numerous epidemiological data and experimental studies support a strong link between fine particulate matter (less than 2.5 mm in aerodynamic diameter, PM_2.5) exposure and the development of insulin resistance/type 2 diabetes mellitus (T2DM). Quercetin (Que), a flavonoid compound with anti-inflammatory effects, has been confirmed to improve glucose metabolic disorders in rodents and humans. In this study, we investigated the underlying mechanisms of particulate matter (PM)-induced glucose metabolic disorder and subsequently examined the protective effect and mechanism of quercetin supplementation. Male C57BL/6 mice in the control group and PM group were exposed to ambient filtered air (FA) or PM (6 h/day, 7 days/week) for 18 weeks. Mice in the Que group were exposed to PM for 18 weeks and administered Que (50 or 100 mg/kg bw). Glucose tolerance, insulin sensitivity, and systemic and visceral white adipose tissue (vWAT) inflammatory responses were measured. The expression of proteins involved in insulin signal transduction in vWAT was assessed. Chronic PM exposure caused systemic and vWAT inflammation characterized by an increase in serum IL-6 and TNF-α levels and increased vWAT macrophage filtration, triggering NLRP3 inflammasome activation, impairing the classic glucose metabolism signal in vWAT, and inducing whole-body insulin resistance. Moreover, Que administration significantly alleviated systemic and vWAT inflammation, abolished NLRP3 inflammasome activation, and improved signaling abnormalities characteristic of insulin resistance in vWAT and adipocytes. Based on these findings, chronic PM exposure activated the NLRP3 inflammasome and subsequently caused systemic and WAT inflammation and impaired insulin signaling in vWAT and adipocytes. Most importantly, Que administration inhibited NLRP3 inflammasome-mediated inflammation and insulin signaling in vWAT to improve these adverse effects.

PM2.5 induces airway hyperresponsiveness and inflammation via the AhR pathway in a sensitized Guinea pig asthma-like model

Exposure to fine particulate matter (PM_2.5) induces airway inflammation and hyperreactivity that lead to asthma. The mechanisms involved are still under investigation. We investigated the effect of resveratrol (3,4',5-trihydroxystilbene) (RES) on airway hyperresponsiveness, inflammation and CYP1A1 protein expression (an aryl hydrocarbon receptor (AhR) target) induced by PM_2.5 exposure in an allergic asthma experimental guinea pig model. The polyphenolic compound RES was used due to its antioxidant and anti-inflammatory properties and as an antagonist of the AhR; thus, providing mechanistic insights. Animals were sensitized with aluminum hydroxide and ovalbumin and exposed to filtered air or PM_2.5. Exposure to PM_2.5 was conducted using a whole-body chamber particle concentrator (5 h/day) for 15 days. Animals received saline solution or RES (10 mg/kg per day) orally for 21 days simultaneously to the OVA challenge or PM_2.5 exposure. PM_2.5 exposure (mean 433 ± 111 μg/m³ in the exposure chamber) in OVA challenged animals induced an asthma-like phenotype characterized by increased baseline lung resistance (Rrs) and central airway resistance (Rn) in response to acetylcholine (ACh) evaluated using a flexiVent system®. A parallel increase of pro-inflammatory cytokines (IL-6, IL-17, TNF-α and IFN-γ), inflammatory cells (eosinophils and neutrophils) in bronchoalveolar lavage fluid (BALF) and lung CYP1A1 increase also occurred. RES significantly inhibited airway hyperresponsiveness, inflammation, and CYP1A1 protein expression in the OVA-challenged PM_2.5 exposed animals. In summary, with the use of RES we demonstrate that PM-induced airway hyperreactivity is modulated by the inflammatory response via the AhR pathway in an allergic asthma guinea pig model.

Protective effects of lotus plumule ethanol extracts on bleomycin-induced pulmonary fibrosis in mice

Pulmonary fibrosis (PF) is a progressive fibrosing disease, characterized by excessive accumulation of extracellular matrix (ECM) and remodeling of the lung architecture, which finally result in respiratory failure. Currently, there is no satisfactory treatment for PF， therefore, the development of effective agents is urgently needed. Lotus plumule, the green embryo of Nelumbo nucifera Gaertn., a plant of the Nymphaeaceae family, is a traditional Chinese food with exceptional nutritional value and its extracts exert prominent anti-inflammatory and anti-fibrotic effects. The aim of the present study was to investigate the inhibitory effects of lotus plumule extracts (LPEs) on bleomycin (BLM)-induced PF in mice. Therefore, enzyme-linked immunosorbent assay, RT-PCR, and western blot analysis were performed. The histopathological examination demonstrated that LPEs could obviously decrease the degree of alveolitis, deposition of ECM and the production of collagen I (Col-I) in the pulmonary interstitium. In addition, the results showed that LPEs markedly alleviated the expression of interleukin (IL)-6, IL-17, transforming growth factor (TGF)-β, and α-smooth muscle actin (α-SMA). Additionally, the content of Col-I and hydroxyproline (HYP) was also attenuated. In conclusion, LPEs could ameliorate the BLM-induced lung fibrosis, thus suggesting that LPEs could serve as a potential therapeutic approach for PF.

PM2.5-induced lung injury is attenuated in macrophage-specific NLRP3 deficient mice

Fine particulate matter (PM2.5) is one of the most important components of environmental pollutants and is associated with lung injury. Pyroptosis, a form of programmed cell death mainly mediated by the NLRP3 inflammasome, has been reported to be involved in sepsis-induced or ischemia/reperfusion-induced lung injury. However, the specific mechanisms of pyroptosis in PM2.5-induced lung injury are not yet clear. We constructed macrophage-specific NLRP3 knockout mice to explore the mechanism of PM2.5-induced lung injury in terms of inflammatory response, oxidative stress, and apoptosis levels, including the relationship between these effects and pyroptosis. The results disclosed that PM2.5 exposure increased the infiltration of macrophages and leukocytes and the secretion of inflammatory cytokines, including TNF-α and IL-6, in lung tissue. The activity of antioxidant enzymes, including SOD, GSH-PX, and CAT, significantly decreased, while MDA, the end product of lipid oxidation, remarkably increased. The level of apoptosis in lung tissue, measured by the TUNEL assay and apoptosis-related proteins (BAX and BCL-2), was significantly increased. Macrophage-specific NLRP3 knockout could offset these effects. We further observed that PM2.5 treatment activated the NLRP3 inflammasome and subsequently induced pyroptosis, as evidenced by the increased production of IL-1β and IL-18 and the increase of the protein levels of NLRP3, ASC, caspase-1, and GSDMD, which were inhibited when NLRP3 was knocked out in macrophages. Taken together, these results revealed that NLRP3-mediated macrophage pyroptosis promoted PM2.5-induced lung injury through aggravating inflammation, oxidative stress, and apoptosis. Targeting the inhibition of NLRP3-mediated macrophage pyroptosis provides a new way to study lung injury induced by the exposure to PM2.5.

Exploring the Use of Medicinal Plants and Their Bioactive Derivatives as Alveolar NLRP3 Inflammasome Regulators during Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is a successful intracellular pathogen that is responsible for the highest mortality rate among diseases caused by bacterial infections. During early interaction with the host innate cells, M. tuberculosis cell surface antigens interact with Toll like receptor 4 (TLR4) to activate the nucleotide-binding domain, leucine-rich-repeat containing family, pyrin domain-containing 3 (NLRP3) canonical, and non-canonical inflammasome pathways. NLRP3 inflammasome activation in the alveoli has been reported to contribute to the early inflammatory response that is needed for an effective anti-TB response through production of pro-inflammatory cytokines, including those of the Interleukin 1 (IL1) family. However, overstimulation of the alveolar NLRP3 inflammasomes can induce excessive inflammation that is pathological to the host. Several studies have explored the use of medicinal plants and/or their active derivatives to inhibit excessive stimulation of the inflammasomes and its associated factors, thus reducing immunopathological response in the host. This review describes the molecular mechanism of the NLRP3 inflammasome activation in the alveoli during M. tuberculosis infection. Furthermore, the mechanisms of inflammasome inhibition using medicinal plant and their derivatives will also be explored, thus offering a novel perspective on the alternative control strategies of M. tuberculosis-induced immunopathology.

Therapeutic Effects and Molecular Mechanisms of Bioactive Compounds Against Respiratory Diseases: Traditional Chinese Medicine Theory and High-Frequency Use

Respiratory diseases, especially the pandemic of respiratory infectious diseases and refractory chronic lung diseases, remain a key clinical issue and research hot spot due to their high prevalence rates and poor prognosis. In this review, we aimed to summarize the recent advances in the therapeutic effects and molecular mechanisms of key common bioactive compounds from Chinese herbal medicine. Based on the theories of traditional Chinese medicine related to lung diseases, we searched several electronic databases to determine the high-frequency Chinese medicines in clinical application. The active compounds and metabolites from the selected medicines were identified using the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) by analyzing oral bioavailability and drug similarity index. Then, the pharmacological effects and molecular mechanisms of the selected bioactive compounds in the viral and bacterial infections, inflammation, acute lung injury (ALI), chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, asthma, and lung cancer were summarized. We found that 31 bioactive compounds from the selected 10 common Chinese herbs, such as epigallocatechin-3-gallate (EGCG), kaempferol, isorhamnetin, quercetin, and β-sitosterol, can mainly regulate NF-κB, Nrf2/HO-1, NLRP3, TGF-β/Smad, MAPK, and PI3K/Akt/mTOR pathways to inhibit infection, inflammation, extracellular matrix deposition, and tumor growth in a series of lung-related diseases. This review provides novel perspectives on the preclinical study and clinical application of Chinese herbal medicines and their bioactive compounds against respiratory diseases.

Resveratrol Can Attenuate Astrocyte Activation to Treat Spinal Cord Injury by Inhibiting Inflammatory Responses

Several preclinical and clinical studies have attempted to elucidate the pathophysiological mechanism associated with spinal cord injury. However, investigations have been unable to define the precise related mechanisms, and this has led to the lack of effective therapeutic agents for the condition. Neuroinflammation is one of the predominant processes that hinder spinal cord injury recovery. Resveratrol is a compound that has several biological features, such as antioxidation, antibacterial, and antiinflammation. Herein, we reviewed preclinical and clinical studies to delineate the role of toll-like receptors, nod-like receptors, and astrocytes in neuroinflammation. In particular, the alteration of astrocytes in SCI causes glial scar formation that impedes spinal cord injury recovery. Therefore, to improve injury recovery would be to prevent the occurrence of this process. Resveratrol is safe and effective in the significant modulation of neuroinflammatory factors, particularly those mediated by astrocytes. Thus, its potential ability to enhance the injury recovery process and ameliorate spinal cord injury.

Prospective Pharmacological Potential of Resveratrol in Delaying Kidney Aging

Aging is an unavoidable part of life. The more aged we become, the more susceptible we become to various complications and damages to the vital organs, including the kidneys. The existing drugs for kidney diseases are mostly of synthetic origins; thus, natural compounds with minimal side-effects have attracted growing interest from the scientific community and pharmaceutical companies. A literature search was carried out to collect published research information on the effects of resveratrol on kidney aging. Recently, resveratrol has emerged as a potential anti-aging agent. This versatile polyphenol exerts its anti-aging effects by intervening in various pathologies and multi-signaling systems, including sirtuin type 1, AMP-activated protein kinase, and nuclear factor-κB. Researchers are trying to figure out the detailed mechanisms and possible resveratrol-mediated interventions in divergent pathways at the molecular level. This review highlights (i) the causative factors implicated in kidney aging and the therapeutic aspects of resveratrol, and (ii) the effectiveness of resveratrol in delaying the aging process of the kidney while minimizing all possible side effects.

Shenlian extract protects against ultrafine particulate matter-aggravated myocardial ischemic injury by inhibiting inflammation response via the activation of NLRP3 inflammasomes

Air pollution is a growing public health burden associated with several negative health effects, especially cardiovascular disease. Shenlian extract (SL), a traditional Chinese medicine, has the effects of clearing heat-toxin and promoting blood circulation for removing blood stasis, and it has long been used to treat cardiovascular diseases and atherosclerosis. This study explored the underlying action mechanism of SL against ultrafine particle-induced myocardial ischemic injury (UFP-MI) through network pharmacology prediction and experimental verification. Male Sprague-Dawley rats with UFP-MI were pre-treated with SL intragastrically for 7 days. All the rats were then euthanized. Inflammatory cytokine detection and histopathological analysis were performed to assess the protective effects of SL. For the mechanism study, differentially expressed genes (DEGs) were identified in UFP-MI rats treated with SL through transcriptomic analysis. Subsequently, in combination with network pharmacology, potential pathways involved in the effects of SL treatment were identified using the Internet-based Computation Platform (www.tcmip.cn) and Cytoscape 3.6.0. Further validation experiments were performed to reveal the mechanism of the therapeutic effects of SL on UFP-MI. The results show that SL significantly suppressed inflammatory cell infiltration into myocardial tissue and exhibited significant anti-inflammatory activity. Transcriptomic analysis revealed that the DEGs after SL treatment had significant anti-inflammatory, immunomodulatory, and anti-viral activities. Network pharmacology analysis illustrated that the targets of SL were mainly involved in regulation of the inflammatory response, apoptotic process, innate immune response, platelet activation, and coagulation process. By combining transcriptomic and network pharmacology data, we found that SL may exert anti-inflammatory effects by acting on the NOD-like signaling pathway to regulate immune response activation and inhibit systemic inflammation. Verification experiments revealed that SL can suppress the secretion of the inflammatory cytokines Interleukin-1 (IL-1), Interleukin-18(IL-18) and Interleukin-33(IL-33) and suppress NLRP3 inflammasome activity. The results suggested that SL can directly inhibit the activation of NLRP3 inflammasomes and reduce the release of cytokines to protect against ultrafine particulate matter-aggravated myocardial ischemic injury.

PM2.5 and water-soluble components induce airway fibrosis through TGF-β1/Smad3 signaling pathway in asthmatic rats

Epidemiological studies have suggested that fine particulate matter (PM_2.5) and asthma have been independently associated with pulmonary fibrosis but rarely studied together. Furthermore, it is unknown whether airway fibrosis in asthma is more attributable to water-soluble ions of PM_2.5. Our current study was to explore the potential mechanism of PM_2.5 and water-soluble components on airway fibrosis in ovalbumin (OVA)-sensitized asthmatic rats. Rats were intratracheally instilled with PM_2.5 and water-soluble components every 3 days for 4 times or 8 times. Histopathological examination demonstrated that lung inflammatory and airway fibrosis were induced after PM_2.5 and water-soluble components exposure. Meanwhile, PM_2.5, in particular water-soluble extracts, increased expression of collagen 1 (COL-1), connective tissue growth factor (CTGF), interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1), Smad family member 3 (Smad3), and p-Smad3, whereas decreased secretion of heme oxygenase-1 (HO-1). However, pretreating asthmatic rats with SB432542, the inhibitor of TGF-β1, and SIS3 HCl, the antagonist of Smad3, both reversed the activation of airway fibrosis induced by water-soluble extracts. Therefore, TGF-β1/Smad3 signaling pathway may be responsible for the pathological process of airway fibrosis in asthmatic rats following PM_2.5 and water-soluble components exposure.

Adipose-derived stem cells therapy effectively attenuates PM2.5-induced lung injury

BACKGROUND

The adverse health effects of fine particulate matter (PM_2.5) exposure are associated with marked inflammatory responses. Adipose-derived stem cells (ADSCs) have immunosuppressive effects, and ADSC transplantation could attenuate pulmonary fibrosis in different animal disease models. However, whether ADSCs affect PM_2.5-induced lung injury has not been investigated.

METHOD

C57BL/6 mice were exposed to PM_2.5 every other day via intratracheal instillation for 4 weeks. After that, the mice received tail vein injections of ADSCs every 2 weeks.

RESULTS

ADSC transplantation significantly attenuated systemic and pulmonary inflammation, cardiac dysfunction, fibrosis, and cell death in PM_2.5-exposed mice. RNA-sequencing results and bioinformatic analysis suggested that the downregulated differentially expressed genes (DEGs) were mainly enriched in inflammatory and immune pathways. Moreover, ADSC transplantation attenuated PM_2.5-induced cell apoptosis and pyroptosis in the lungs and hearts.

CONCLUSION

ADSCs protect against PM_2.5-induced adverse health effects through attenuating pulmonary inflammation and cell death. Our findings suggest that ADSC transplantation may be a potential therapeutic approach for severe air pollution-associated diseases.

Phytochemical inhibitors of the NLRP3 inflammasome for the treatment of inflammatory diseases

The NLRP3 inflammasome holds a crucial role in innate immune responses. Pathogen- and danger-associated molecular patterns may initiate inflammasome activation and following inflammatory cytokine release. The inflammasome formation and its-associated activity are involved in various pathological conditions such as cardiovascular, central nervous system, metabolic, renal, inflammatory and autoimmune diseases. Although the mechanism behind NLRP3-mediated disorders have not been entirely illuminated, many phytochemicals and medicinal plants have been described to prevent inflammatory disorders. In the present review, we mainly introduced phytochemicals inhibiting NLRP3 inflammasome in addition to NLRP3-mediated diseases. For this purpose, we performed a systematic literature search by screening PubMed, Scopus, and Google Scholar databases. By compiling the data of phytochemical inhibitors targeting NLRP3 inflammasome activation, a complex balance between inflammasome activation or inhibition with NLRP3 as central player was pointed out in NLRP3-driven pathological conditions. Phytochemicals represent potential therapeutic leads, enabling the generation of chemical derivatives with improved pharmacological features to treat NLRP3-mediated inflammatory diseases.

Hyperoside relieves particulate matter-induced lung injury by inhibiting AMPK/mTOR-mediated autophagy deregulation

Autophagy-mediated cell death plays a critical role in the pathogenesis of PMs-induced lung injury. Hyperoside (Hyp), a flavonoid glycosides, is known to exert protective effects on many diseases by inhibiting autophagic activity. The current study aimed to explore the protective effect and mechanism of Hyp against PMs-induced lung injury in PM2.5 challenged Beas-2b cells in vitro and BALB/C mice in vivo. In vitro, we found that the organic solvent-extractable fraction of SRM1649b (O-PMs) caused more severe cytotoxicity in Beas-2b cells than the water solvent-extractable fraction of SRM1649b (W-PMs). O-PMs treatment dose-dependently upregulated the expression of autophagy markers (beclin-1, p62, atg3 and LC3II) and apoptotic proteins. This cytotoxicity of O-PMs was attenuated by Hyp pretreatment in parallel with downregulation of the expression of autophagy markers, apoptotic proteins, and p-AMPK and upregulation of p-mTOR expression. Notably, the therapeutic effect of Hyp was attenuated by pretreated with AICAR (an AMPK inducer), but enhanced by CC and 3-MA treatment. In vivo, Hyp reduced pathological lung injury and decreased the levels of PMs-induced inflammatory cytokines (TNF-α and IL-6), and the number of total cells in the BALF by inhibiting AMPK/mTOR signaling. Furthermore, cotreatment with AICAR (500 mg/kg) reduced but did not abrogate the pulmonary protective effect of Hyp. These findings indicate that Hyp protects against PMs-induced lung injury by suppressing autophagy deregulation and apoptosis through regulation of the AMPK/mTOR pathway.