Diosmetin Alleviates Lipopolysaccharide-Induced Acute Lung Injury through Activating the Nrf2 Pathway and Inhibiting the NLRP3 Inflammasome

Preventive Effect of the Total Polyphenols from Nymphaea candida on Sepsis-Induced Acute Lung Injury in Mice via Gut Microbiota and NLRP3, TLR-4/NF-κB Pathway

This study aimed to investigate the preventive effects of the total polyphenols from Nymphaea candida (NCTP) on LPS-induced septic acute lung injury (ALI) in mice and its mechanisms. NCTP could significantly ameliorate LPS-induced lung tissue pathological injury in mice as well as lung wet/dry ratio and MPO activities (p < 0.05). NCTP could significantly decrease the blood leukocyte, neutrophil, monocyte, basophil, and eosinophil amounts and LPS contents in ALI mice compared with the model group (p < 0.05), improving lymphocyte amounts (p < 0.05). Moreover, compared with the model group, NCTP could decrease lung tissue TNF-α, IL-6, and IL-1β levels (p < 0.05) and downregulate the protein expression of TLR4, MyD88, TRAF6, IKKβ, IκB-α, p-IκB-α, NF-κB p65, p-NF-κB p65, NLRP3, ASC, and Caspase1 in lung tissues (p < 0.05). Furthermore, NCTP could inhibit ileum histopathological injuries, restoring the ileum tight junctions by increasing the expression of ZO-1 and occludin. Simultaneously, NCTP could reverse the gut microbiota disorder, restore the diversity of gut microbiota, increase the relative abundance of Clostridiales and Lachnospiraceae, and enhance the content of SCFAs (acetic acid, propionic acid, and butyric acid) in feces. These results suggested that NCTP has preventive effects on septic ALI, and its mechanism is related to the regulation of gut microbiota, SCFA metabolism, and the TLR-4/NF-κB and NLRP3 pathways.

Anti-Inflammatory Properties of the Citrus Flavonoid Diosmetin: An Updated Review of Experimental Models

Inflammation is an essential contributor to various human diseases. Diosmetin (3',5,7-trihydroxy-4'-methoxyflavone), a citrus flavonoid, can be used as an anti-inflammatory agent. All the information in this article was collected from various research papers from online scientific databases such as PubMed and Web of Science. These studies have demonstrated that diosmetin can slow down the progression of inflammation by inhibiting the production of inflammatory mediators through modulating related pathways, predominantly the nuclear factor-κB (NF-κB) signaling pathway. In this review, we discuss the anti-inflammatory properties of diosmetin in cellular and animal models of various inflammatory diseases for the first time. We have identified some deficiencies in current research and offer suggestions for further advancement. In conclusion, accumulating evidence so far suggests a very important role for diosmetin in the treatment of various inflammatory disorders and suggests it is a candidate worthy of in-depth investigation.

Vaping-Dependent Pulmonary Inflammation Is Ca2+ Mediated and Potentially Sex Specific

Here we use the SCIREQ InExpose system to simulate a biologically relevant vaping model in mice to investigate the role of calcium signaling in vape-dependent pulmonary disease as well as to investigate if there is a gender-based difference of disease. Male and female mice were vaped with JUUL Menthol (3% nicotine) using the SCIREQ InExpose system for 2 weeks. Additionally, 2-APB, a known calcium signaling inhibitor, was administered as a prophylactic for lung disease and damage caused by vaping. After 2 weeks, mice were exposed to lipopolysaccharide (LPS) to mimic a bacterial infection. Post-infection (24 h), mice were sacrificed, and bronchoalveolar lavage fluid (BALF) and lungs were taken. Vaping primed the lungs for worsened disease burden after microbial challenge (LPS) for both males and females, though females presented increased neutrophilia and inflammatory cytokines post-vape compared to males, which was assessed by flow cytometry, and cytokine and histopathological analysis. This increased inflammatory burden was controlled by calcium signaling inhibition, suggesting that calcium dysregulation may play a role in lung injury caused by vaping in a gender-dependent manner.

Diosmetin alleviates neuropathic pain by regulating the Keap1/Nrf2/NF-κB signaling pathway

BACKGROUND

Neuropathic pain, a chronic condition with a high incidence, imposes psychological burdens on both patients and society. It is urgent to improve pain management and develop new analgesic drugs. Traditional Chinese medicine has gained popularity as a method for pain relief. Diosmetin (Dio) is mainly found in Chinese herbal medicines with effective antioxidant, anti-cancer, and anti-inflammatory properties. There are few known mechanisms underlying the effectiveness of Dio in treating neuropathic pain. However, the complete understanding of its therapeutic effect is missing.

PURPOSE

This study aimed to evaluate Dio's therapeutic effects on neuropathic pain models and determine its possible mechanism of action. We hypothesized that Dio may activate antioxidants and reduce inflammation, inhibit the activation of Kelch-like epichlorohydrin-associated protein 1 (Keap1) and nuclear factor-k-gene binding (NF-κB), promote the metastasis of nuclear factor erythroid 2-related factor 2 (Nrf2) and the expression of heme oxygenase 1 (HO-1), thus alleviating the neuropathic pain caused by spinal nerve ligation.

METHODS

Chronic nociceptive pain mouse models were established in vivo by L4 spinal nerve ligation (SNL). Different dosages of Dio (10, 50, 100 mg/kg) were intragastrically administered daily from the third day after the establishment of the SNL model. Allodynia, caused by mechanical stimuli, and hyperalgesia, caused by heat, were assessed using the paw withdrawal response frequency (PWF) and paw withdrawal latency (PWL), respectively. Cold allodynia were assessd by acetone test. RT-PCR was used to detect the content of interleukin-(IL)- 1β, IL-6 and tumor necrosis factor (TNF)-a. Immunofluorescence and western blotting were employed to assess the expression levels of Glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule (Iba1), Keap1, Nrf2, HO-1, and NF-κB p-p65 protein.

RESULTS

Dio administration relieved SNL-induced transient mechanical and thermal allodynia in mice. The protective effect of Dio in the SNL model was associated with its anti-inflammatory and anti-glial responses in the spinal cord. Dio inhibited both inflammatory factors and macrophage activation in the DRG. Furthermore, Dio regulated the Keap1/Nrf2/NF-κB signaling pathway. HO-1 and Nrf2 were upregulated following Dio administration, which also decreased the levels of Keap1 and NF-κB p65 protein.

CONCLUSION

Mice with SNL-induced neuropathic pain were therapeutically treated with Dio. Dio may protect against pain by inhibiting inflammatory responses and improved Keap1/Nrf2/NF-κB pathway. These results highlight the potential therapeutic effect of Dio for the development of new analgesic drugs.

The Antioxidative Effects of Flavones in Hypertensive Disease

Hypertension is the leading remediable risk factor for cardiovascular morbidity and mortality in the United States. Excess dietary salt consumption, which is a catalyst of hypertension, initiates an inflammatory cascade via activation of antigen-presenting cells (APCs). This pro-inflammatory response is driven primarily by sodium ions (Na+) transporting into APCs by the epithelial sodium channel (ENaC) and subsequent NADPH oxidase activation, leading to high levels of oxidative stress. Oxidative stress, a well-known catalyst for hypertension-related illness development, disturbs redox homeostasis, which ultimately promotes lipid peroxidation, isolevuglandin production and an inflammatory response. Natural medicinal compounds derived from organic materials that are characterized by their anti-inflammatory, anti-oxidative, and anti-mutagenic properties have recently gained traction amongst the pharmacology community due to their therapeutic effects. Flavonoids, a natural phenolic compound, have these therapeutic benefits and can potentially serve as anti-hypertensives. Flavones are a type of flavonoid that have increased anti-inflammatory effects that may allow them to act as therapeutic agents for hypertension, including diosmetin, which is able to induce significant arterial vasodilation in several different animal models. This review will focus on the activity of flavones to illuminate potential preventative and potential therapeutic mechanisms against hypertension.

Research Progress on Natural Small-Molecule Compounds for the Prevention and Treatment of Sepsis

Sepsis is a serious disease with high mortality and has been a hot research topic in medical research in recent years. With the continuous reporting of in-depth research on the pathological mechanisms of sepsis, various compounds have been developed to prevent and treat sepsis. Natural small-molecule compounds play vital roles in the prevention and treatment of sepsis; for example, compounds such as resveratrol, emodin, salidroside, ginsenoside, and others can modulate signaling through the NF-κB, STAT3, STAT1, PI3K, and other pathways to relieve the inflammatory response, immunosuppression, and organ failure caused by sepsis. Here, we discuss the functions and mechanisms of natural small-molecule compounds in preventing and treating sepsis. This review will lay the theoretical foundation for discovering new natural small-molecule compounds that can potentially prevent and treat sepsis.

Safflor Yellow A Protects Beas-2B Cells Against LPS-Induced Injury via Activating Nrf2

Acute lung injury and its severe form acute respiratory distress syndrome are lethal lung diseases. So far, effective therapy for the diseases is deficient and the prognosis is poor. Recently, it was found activating nuclear factor erythroid 2-related factor 2 could attenuate the injury including inflammation, oxidative stress, and apoptosis in those diseases. To discover novel therapy, we have evaluated safflor yellow A and explored the underlying mechanisms using Beas-2B cells injured by lipopolysaccharide. As a result, safflor yellow A could improve the viability of Beas-2B cells treated with lipopolysaccharide. Further investigations have revealed safflor yellow A suppressed oxidative stress induced by lipopolysaccharide via reducing reactive oxygen species and malondialdehyde, and elevating superoxide dismutase, catalase, and glutathione peroxidase. Meanwhile, the inflammation resulting from lipopolysaccharide was ameliorated through decreasing the pro-inflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and interleukin-6. It was also found nuclear factor κB was inactivated by safflor yellow A. In addition, safflor yellow A downregulated cysteinyl aspartate specific proteinase-3 and Bcl-2-associated X protein and upregulated B-cell lymphoma-2 to inhibited apoptosis of Beas-2B cells induced by lipopolysaccharide. The activation of nuclear factor erythroid 2-related factor 2 was observed in Beas-2B cells, which was associated with the protective effects of safflor yellow A. And molecular docking elucidated safflor yellow A interacted with Kelch-like ECH-associated protein 1 to activate nuclear factor erythroid 2-related factor 2. These results can provide evidences for the discovery of novel therapy for further evaluation of safflor yellow A in the treatment of acute lung injury and acute respiratory distress syndrome.

Graphical Abstract

Beneficial effects of flavonoids on cardiovascular diseases by influencing NLRP3 inflammasome

Cardiovascular diseases (CVDs) are a leading cause of global mortality and have a high incidence rate worldwide. The function of inflammasomes in CVDs has received a lot of attention recently, and the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome may be a new target for the prevention and treatment of CVDs. Flavonoids, which are found in food and plant extracts, inhibited inflammation in CVDs by regulating the NLRP3 inflammasome. CB-Dock was used to investigate whether 34 flavonoids from natural products acted on NLRP3 inflammasome. In brief, the PDB format of NLRP3 was selected as a protein file, and 34 flavonoids in SDF format were selected as the ligand file, and then input to CB-Dock for molecular docking. The docking results showed that epigallocatechin-3-gallate (EGCG), amentoflavone, baicalin, scutellarin, vitexin, silibinin, and puerarin had good binding affinities to NLRP3, which could be used as NLRP3 inhibitors, and aid in the discovery of lead compounds for the design and development of CVDs.

Aloperine alleviates lipopolysaccharide-induced acute lung injury by inhibiting NLRP3 inflammasome activation

RATIONALE

Excessive activation of the NLRP3 inflammasome is involved in the pathological progression of acute lung injury (ALI). Aloperine (Alo) has anti-inflammatory effects in many inflammatory disease models; however, its role in ALI remains elusive. In this study, we addressed the role of Alo in NLRP3 inflammasome activation in both ALI mice and LPS-treated RAW264.7 cells.

METHODS

The activation of the NLRP3 inflammasome in LPS-induced ALI lungs was investigated in C57BL/6 mice. Alo was administered in order to study its effect on NLRP3 inflammasome activation in ALI. RAW264.7 cells were used to evaluate the underlying mechanism of Alo in the activation of the NLRP3 inflammasome in vitro.

RESULTS

The activation of the NLRP3 inflammasome occurs in the lungs and RAW264.7 cells under LPS stress. Alo attenuated the pathological injury of lung tissue as well as downregulates the mRNA expression of NLRP3 and pro-caspase-1 in ALI mice and LPS-stressed RAW264.7 cells. The expression of NLRP3, pro-caspase-1, and caspase-1 p10 were also significantly suppressed by Alo in vivo and in vitro. Furthermore, Alo decreased IL-1β and IL-18 release in ALI mice and LPS-induced RAW264.7 cells. In addition, ML385, a Nrf2 inhibitor, weakened the activity of Alo, which inhibited the activation of the NLRP3 inflammasome in vitro.

CONCLUSION

Alo reduces NLRP3 inflammasome activation via the Nrf2 pathway in ALI mice.

Quercus coccinea Münchh leaves polyphenols: Appraisal acute lung injury induced by lipopolysaccharide in mice

Genus Quercus is a well-known source for its polyphenolic content and important biological activity. Plants belonging to the Quercus genus were traditionally used in asthma, inflammatory diseases, wound healing, acute diarrhea, and hemorrhoid. Our work intended to study the polyphenolic profile of the Q. coccinea (QC) leaves and to assess the protective activity of its 80% aqueous methanol extract (AME) against lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Together, the potential molecular mechanism was investigated. Nineteen polyphenolic compounds (1-18), including tannins, flavone, and flavonol glycosides. Phenolic acids and aglycones were purified and identified from the AME of QC leaves. Treatment with AME of QC showed an anti-inflammatory effect evidenced by a remarkable decline in the count of white blood cells and neutrophils which was in harmony with decreasing the levels of high mobility group box-1, nuclear factor kappa B, tumor necrosis factor-α, and interleukin 1 beta. In addition, the antioxidant activity of QC was documented through the significant reduction in malondialdehyde level and elevation of reduced glutathione level and superoxide dismutase activity. Furthermore, the mechanism involved in the pulmonary protective effect of QC involved the downregulation of the TLR4/MyD88 pathway. The AME of QC showed a protective effect against LPS-induced ALI through the powerful anti-inflammatory and antioxidant activities which are linked to its abundancy with polyphenols.

Diosmetin alleviates acute lung injury caused by lipopolysaccharide by targeting barrier function

Acute lung injury (ALI) is an acute and devastating disease caused by systemic inflammation e.g. patients infected with bacteria and viruses such as SARS-CoV-2 have an unacceptably high mortality rate. It has been well documented that endothelial cell damage and repair play a central role in the pathogenesis of ALI because of its barrier function. Nevertheless, the leading compounds that effectively accelerate endothelial cell repair and improve barrier dysfunction in ALI are largely unknown. In the present study, we found that diosmetin had promising characteristics to inhibit the inflammatory response and accelerate the repair of endothelial cells. Our results indicated that diosmetin accelerated wound healing and barrier repair by improving the expression of the barrier-related proteins, including zonula occludens-l (ZO-1) and occludin, in human umbilical vein endothelial cells (HUVECs) treated with lipopolysaccharide (LPS). Meanwhile, diosmetin administration significantly inhibited inflammatory response by decreasing the content of TNFα and IL-6 in the serum, alleviated lung injury by reducing lung wet/dry (W/D) ratio and histologic score, improved endothelial hyperpermeability by decreasing protein levels and neutrophil infiltration in the bronchoalveolar lavage fluid (BALF) and increasing ZO-1 and occludin expression in the lung tissues of LPS-treated mice. Mechanistically, diosmetin also mediated the expression of Rho A and ROCK1/2 in HUVECs treated with LPS, and fasudil, a Rho A inhibitor remarkably inhibited the role of diosmetin in ZO-1 and occludin proteins. All these findings of this study revealed that diosmetin can be an effective protector of lung injury and the Rho A/ROCK1/2 signal pathway plays a pivotal role in diosmetin accelerating barrier repair in ALI.

Diosmetin alleviates benzo[a]pyrene-exacerbated H1N1 influenza virus-induced acute lung injury and dysregulation of inflammation through modulation of the PPAR-γ-NF-κB/P38 MAPK signaling axis

The severity of a viral respiratory illness was greatly exacerbated after exposure to a contaminant containing benzo[a]pyrene (B[a]P). Flavonoid-rich fruit intake has gained intense interest due to their health-promoting benefits for viral respiratory diseases, including influenza viruses. In our study, diosmetin (3',5,7-trihydroxy-4'-methoxyflavone), a naturally occurring hydroxylated methoxyflavone that is abundant in Citrus fruits, was explored for its effects on B[a]P-exacerbated H1N1 influenza virus-mediated inflammation and lung injury. Initially, in vivo results demonstrated that diosmetin protected against H1N1 virus-elicited acute lung injury. Simultaneously, H1N1 virus or B[a]P-stimulated A549 cells treated with diosmetin inhibited NF-κB and P-P38 activation, resulting in suppression of pro-inflammatory cytokines and apoptosis. Interestingly, diosmetin obviously promoted the expression of PPAR-γ as well as nuclear translocation of PPAR-γ, whereas, PPAR-γ inhibition by GW9662 weakened the inhibitory effects of diosmetin on H1N1 virus or B[a]P-mediated activation of NF-κB and P-P38, elevated expression of pro-inflammatory mediators as well as apoptosis. Furthermore, it was surprising to discover that mice exposed to both B[a]P and H1N1 viruses contributed to exacerbated acute lung injury, which were significantly ameliorated by diosmetin administration. In vitro studies showed that A549 cells with the combination of B[a]P and H1N1 virus augmented NF-κB and P-P38 activation, accompanied by higher levels of pro-inflammatory mediators and apoptosis, all of which were also significantly reduced by diosmetin treatment. Repressing PPAR-γ abrogated the inhibitory effects of diosmetin on B[a]P-exacerbated H1N1 virus-mediated NF-κB and P-P38 activation, inflammation, and apoptosis in A549 cells. Our findings suggest that diosmetin protected against B[a]P-exacerbated H1N1 virus-mediated lung injury by suppressing the exacerbation of NF-κB and P38 kinase activation in a PPAR-γ-dependent manner, suggesting potential benefits for B[a]P-exacerbated influenza-related illness therapeutics.

Role of mitochondrial stress and the NLRP3 inflammasome in lung diseases

BACKGROUND

As an organelle essential for intracellular energy supply, mitochondria are involved in intracellular metabolism and inflammation, and cell death. The interaction of mitochondria with the NLRP3 inflammasome in the development of lung diseases has been extensively studied. However, the exact mechanism by which mitochondria mediate the activation of the NLRP3 inflammasome and trigger lung disease is still unclear.

METHODS

The literatures related to mitochondrial stress, NLRP3 inflammasome and lung diseases were searched in PubMed.

RESULTS

This review aims to provide new insights into the recently discovered mitochondrial regulation of the NLRP3 inflammasome in lung diseases. It also describes the crucial roles of mitochondrial autophagy, long noncoding RNA, micro RNA, altered mitochondrial membrane potential, cell membrane receptors, and ion channels in mitochondrial stress and regulation of the NLRP3 inflammasome, in addition to the reduction of mitochondrial stress by nuclear factor erythroid 2-related factor 2 (Nrf2). The effective components of potential drugs for the treatment of lung diseases under this mechanism are also summarized.

CONCLUSION

This review provides a resource for the discovery of new therapeutic mechanisms and suggests ideas for the development of new therapeutic drugs, thus promoting the rapid treatment of lung diseases.

Role of Plant-Derived Compounds in the Molecular Pathways Related to Inflammation

Inflammation is the primary response to infection and injury. Its beneficial effect is an immediate resolution of the pathophysiological event. However, sustained production of inflammatory mediators such as reactive oxygen species and cytokines may cause alterations in DNA integrity and lead to malignant cell transformation and cancer. More attention has recently been paid to pyroptosis, which is an inflammatory necrosis that activates inflammasomes and the secretion of cytokines. Taking into consideration that phenolic compounds are widely available in diet and medicinal plants, their role in the prevention and support of the treatment of chronic diseases is apparent. Recently, much attention has been paid to explaining the significance of isolated compounds in the molecular pathways related to inflammation. Therefore, this review aimed to screen reports concerning the molecular mode of action assigned to phenolic compounds. The most representative compounds from the classes of flavonoids, tannins, phenolic acids, and phenolic glycosides were selected for this review. Our attention was focused mainly on nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), and mitogen-activated protein kinase (MAPK) signaling pathways. Literature searching was performed using Scopus, PubMed, and Medline databases. In conclusion, based on the available literature, phenolic compounds regulate NF-κB, Nrf2, and MAPK signaling, which supports their potential role in chronic inflammatory disorders, including osteoarthritis, neurodegenerative diseases, cardiovascular, and pulmonary disorders.

Potential Treatment of COVID-19 with Traditional Chinese Medicine: What Herbs Can Help Win the Battle with SARS-CoV-2?

Traditional Chinese medicine (TCM) has been successfully applied worldwide in the treatment of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the pharmacological mechanisms underlying this success remain unclear. Hence, the aim of this review is to combine pharmacological assays based on the theory of TCM in order to elucidate the potential signaling pathways, targets, active compounds, and formulas of herbs that are involved in the TCM treatment of COVID-19, which exhibits combatting viral infections, immune regulation, and amelioration of lung injury and fibrosis. Extensive reports on target screening are elucidated using virtual prediction via docking analysis or network pharmacology based on existing data. The results of these reports indicate that an intricate regulatory mechanism is involved in the pathogenesis of COVID-19. Therefore, more pharmacological research on the natural herbs used in TCM should be conducted in order to determine the association between TCM and COVID-19 and account for the observed therapeutic effects of TCM against COVID-19.

Mechanistic Understanding of Lung Inflammation: Recent Advances and Emerging Techniques

Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury characterized by an acute inflammatory response in the lung parenchyma. Hence, it is considered as the most appropriate clinical syndrome to study pathogenic mechanisms of lung inflammation. ARDS is associated with increased morbidity and mortality in the intensive care unit (ICU), while no effective pharmacological treatment exists. It is very important therefore to fully characterize the underlying pathobiology and the related mechanisms, in order to develop novel therapeutic approaches. In vivo and in vitro models are important pre-clinical tools in biological and medical research in the mechanistic and pathological understanding of the majority of diseases. In this review, we will present data from selected experimental models of lung injury/acute lung inflammation, which have been based on clinical disorders that can lead to the development of ARDS and related inflammatory lung processes in humans, including ventilation-induced lung injury (VILI), sepsis, ischemia/reperfusion, smoke, acid aspiration, radiation, transfusion-related acute lung injury (TRALI), influenza, Streptococcus (S.) pneumoniae and coronaviruses infection. Data from the corresponding clinical conditions will also be presented. The mechanisms related to lung inflammation that will be covered are oxidative stress, neutrophil extracellular traps, mitogen-activated protein kinase (MAPK) pathways, surfactant, and water and ion channels. Finally, we will present a brief overview of emerging techniques in the field of omics research that have been applied to ARDS research, encompassing genomics, transcriptomics, proteomics, and metabolomics, which may recognize factors to help stratify ICU patients at risk, predict their prognosis, and possibly, serve as more specific therapeutic targets.

Prostaglandin D2 Attenuates Lipopolysaccharide-Induced Acute Lung Injury through the Modulation of Inflammation and Macrophage Polarization

Acute lung injury (ALI) is a well-known respiratory disease and a leading cause of death worldwide. Despite advancements in the medical field, developing complete treatment strategies against this disease is still a challenge. In the current study, the therapeutic role of prostaglandin D2 (PGD2) was investigated on lipopolysaccharide (LPS)-induced lung injury in mice models and RAW264.7 macrophages through anti-inflammatory, histopathology, immunohistochemistry, and TUNEL staining. The overproduction of cytokines by RAW264.7 macrophages was observed after stimulation with LPS. However, pretreatment with PGD2 decreased the production of cytokines. The level of inflammatory markers was significantly restored in the PGD2 treatment group (TNF-α = 58.6 vs. 78.5 pg/mL; IL-1β = 29.3 vs. 36.6 pg/mL; IL-6 = 75.4 vs. 98.2 pg/mL; and CRP = 0.84 vs. 1.14 ng/mL). The wet/dry weight ratio of the lungs was quite significant in the disease control (LPS-only treatment) group. Moreover, the histological changes as determined by haematoxylin and eosin (H&E) staining clearly showed that PGD2 treatment maintains the lung tissue architecture. The iNOS expression pattern was increased in lung tissues of LPS-treated animals, whereas, in mice treated with PGD2, the expression of iNOS protein decreased. Flow cytometry data demonstrated that LPS intoxication enhanced apoptosis, which significantly decreased with PGD2 treatment. In conclusion, all these observations indicate that PGD2 provides an anti-inflammatory response in RAW264.7 macrophages and in ALI, and they suggest a therapeutic potential in lung pathogenesis.

Diosmetin alleviates cerebral ischemia-reperfusion injury through Keap1-mediated Nrf2/ARE signaling pathway activation and NLRP3 inflammasome inhibition

Diosmetin was found to exert protective effect on renal and myocardial ischemia-reperfusion (IR) injury. This study aimed to investigate the role of diosmetin in cerebral IR (CIR) injury. PC12 neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to establish CIR injury model in vitro and then incubated with diosmetin, and we found that diosmetin alleviated OGD/R-induced viability inhibition, LDH release, apoptosis, and oxidative stress in PC12 cells. Then our results showed that diosmetin downregulated kelch like ECH-associated protein 1 (Keap1) expression, and upregulated nuclear factor E2-related factor 2 (Nrf2) expression, antioxidant response element (ARE) activity and the mRNA and protein expression of heme oxygenase 1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO1). Keap1 overexpression or Nrf2 silencing both attenuated the neuroprotective effect of diosmetin on PC12 cells. Moreover, diosmetin inhibited the levels of nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) pyrin domain containing 3 (NLRP3) inflammasome pathway related proteins and inflammatory cytokines interleukin (IL)-1β and IL-18. Additionally, a middle cerebral artery occlusion (MCAO) rat model was established and diosmetin was injected for treatment. Diosmetin alleviated CIR-induced neurological deficits, cerebral infarction, brain edema and histopathological damage, and neuronal apoptosis and oxidative stress in MCAO rats. In conclusion, diosmetin attenuated OGD/R-induced PC12 cell viability inhibition, apoptosis, oxidative stress and inflammation through Keap1-mediated Nrf2/ARE signaling activation and NLRP3 inflammasome inhibition, and alleviated CIR-induced neurological injury in MCAO rat model. Our study may provide a novel therapeutic strategy for CIR injury.

Diosmetin has therapeutic efficacy in colitis regulating gut microbiota, inflammation, and oxidative stress via the circ-Sirt1/Sirt1 axis

Diosmetin (3',5,7 -trihydroxy-4'-methoxy flavone) is a natural flavonoid compound in the citrus species, it exhibits a variety of pharmacological activities, but little is known of its effects on colitis. In this study we evaluated the therapeutic effects of diosmetin on mouse models of chronic and acute colitis. Chronic colitis was induced in mice by drinking water containing 3% dextran sulfate sodium (DSS) from D0 to D8, followed by administration of diosmetin (25, 50 mg · kg^-1 · d^-1) for another 8 days. Acute colitis was induced by drinking water containing 5% DSS from D0 to D7, the mice concomitantly received diosmetin (25, 50 mg · kg^-1 · d^-1) from D1 to D7. During the experiments, body weight and disease activity index (DAI) were assessed daily. After the mice were sacrificed, colon tissue and feces samples were collected, and colon length was measured. We showed that in both models, diosmetin administration significantly decreased DAI score and ameliorated microscopic colon tissue damage; increased the expression of tight junction proteins (occludin, claudin-1, and zonula occludens-1), and reduced the secretion of proinflammatory cytokines IL-1β, IL-6, TNF-α, and Cox-2 in colon tissue. We found that diosmetin administration remarkably inhibited colon oxidative damage by adjusting the levels of intracellular and mitochondrial reactive oxygen species, GSH-Px, SOD, MDA and GSH in colon tissue. The protection of diosmetin against intestinal epithelial barrier damage and oxidative stress were also observed in LPS-treated Caco-2 and IEC-6 cells in vitro. Furthermore, we demonstrated that diosmetin markedly increased the expression of Nrf2 and HO-1 and reduced the ratio of acetylated NF-κB and NF-κB by activating the circ-Sirt1/Sirt1 axis, which inhibited oxidative stress and inflammation in vivo and in vitro. Diosmetin reversed the effects of si-circSirt1 and si-Sirt1 in LPS-treated Caco-2 and IEC-6 cells. When the gut microbiota was analyzed in the mouse model of colitis, we found that diosmetin administration modulated the abundance of Bacteroidetes, Actinobacteria, Cyanobacteria and Firmicutes, which were crucial for inflammatory bowel disease. Our results have linked colitis to the circ-Sirt1/Sirt1 signaling pathway, which is activated by diosmetin. The results imply that diosmetin may be a novel candidate to alleviate DSS-induced colitis and can be a lead compound for future optimization and modification.

Diosmetin Protects against Cardiac Hypertrophy via p62/Keap1/Nrf2 Signaling Pathway

An important pathophysiological consequence of pressure overload-induced cardiac hypertrophy is adverse cardiac remodeling, including structural changes in cardiomyocytes and extracellular matrix. Diosmetin (DIO), a monomethoxyflavone isolated from citrus fruits, had antioxidative stress effects in multiple organs. The purpose of this study was to examine the biological effect of diosmetin on pathological cardiac hypertrophy. In mice, diosmetin treatment reduced cardiac hypertrophy and dysfunction in an aortic banding- (AB-) induced pressure overload model and reducing myocardial oxidative stress by increasing antioxidant gene expression. In vitro, diosmetin (10 or 50 μm, 12 h or 24 h) protected PE-induced cardiomyocyte hypertrophy in neonatal rat cardiomyocytes. Mechanistically, diosmetin inhibited autophagy by activating the PI3K/Akt pathway. In particular, diosmetin induced the accumulation of p62 and its interaction with Keap1, promoted the nuclear translocation of Nrf2, and increased the expression of antioxidant stress genes in the process of cardiac hypertrophy. Furthermore, knockdown of p62 in rat primary cardiomyocytes abrogate the protective effect of diosmetin on cardiomyocyte hypertrophy. Similarly, the Nrf2 inhibitor ML385 obviously abolished the above effects by diosmetin treatment. In conclusion, our results suggest that diosmetin protects cardiac hypertrophy under pressure overload through the p62/Keap1/Nrf2 signaling pathway, suggesting the potential of diosmetin as a novel therapy for pathological cardiac hypertrophy.

The Value of Pulmonary Bedside Ultrasound System in the Evaluation of Severity and Prognosis of Acute Lung Injury

Objective. To evaluate the value of pulmonary bedside ultrasound system in the assessment of severity and prognosis of acute lung injury (ALI). Method. Seventy-two ALI patients in the intensive care unit (ICU) of our hospital from April 2019 to April 2021 were selected as subjects. The changes of lung ultrasound score (LUS) and parameters at D1, D2, and D3 after admission were analyzed (LUS, oxygenation index (PaO2/FiO2), Acute Physiology and Chronic Health Evaluation II (APACHE-II), and Sequential Organ Failure Assessment (SOFA) score). Pearson correlation analysis was used to assess the relationship between LUS and PaO2/FiO2, APACHE-II score, and SOFA score at D1, D2, and D3. Logistic regression analysis was used for influencing factors for the prognosis of ALI patients. Receiver operating characteristic (ROC) curve was used to analyze the predictive value of baseline LUS, PaO2/FiO2, APACHE-II score, and SOFA score for the prognosis of ALI patients. Result. LUSs at D1, D2 and D3 showed an increasing trend with the increase of disease severity ( $P<0.05$ ). From D1 to D3, LUS, PaO2/FiO2, APACHE-II score, and SOFA score showed a downward trend ( $P<0.05$ ). LUS was negatively correlated with PaO2/FiO2 at D1, D2, and D3 but positively correlated with APACHE-II score and SOFA score ( $P<0.05$ ). Logistic regression analysis showed that after controlling for age, PaO2 and PaCO2, an increase in baseline LUS, APACHE-II score, SOFA score, and a decrease in PaO2/FiO2 were independent risk factors for death at 28 d in ALI patients ( $P<0.05$ ). ROC curve showed that LUS, PaO2/FiO2, APACHE-II score, and SOFA score were combined to predict the prognosis of ALI patients with the highest AUC value of 0.920, corresponding sensitivity of 88.89%, and specificity of 95.56%. Conclusion. LUS can evaluate the change of pulmonary ventilation area in ALI patients, further evaluate the severity of the disease, and effectively predict the prognosis of patients.

Ginsenoside Rb1 Attenuates Triptolide-Induced Cytotoxicity in HL-7702 Cells via the Activation of Keap1/Nrf2/ARE Pathway

Triptolide (TP) is the major bioactive compound extracted from Tripterygium wilfordii Hook F. It exerts anti-inflammatory, antirheumatic, antineoplastic, and neuroprotective effects. However, the severe hepatotoxicity induced by TP limits its clinical application. Ginsenoside Rb1 has been reported to possess potential hepatoprotective effects, but its mechanism has not been fully investigated. This study was aimed at investigating the effect of ginsenoside Rb1 against TP-induced cytotoxicity in HL-7702 cells, as well as the underlying mechanism. The results revealed that ginsenoside Rb1 effectively reversed TP-induced cytotoxicity in HL-7702 cells. Apoptosis induced by TP was suppressed by ginsenoside Rb1 via inhibition of death receptor-mediated apoptotic pathway and mitochondrial-dependent apoptotic pathway. Pretreatment with ginsenoside Rb1 significantly reduced Bax/Bcl-2 ratio and down-regulated the expression of Fas, cleaved poly ADP-ribose polymerase (PARP), cleaved caspase-3, and -9. Furthermore, ginsenoside Rb1 reversed TP-induced cell cycle arrest in HL-7702 cells at S and G2/M phase, via upregulation of the expressions of cyclin-dependent kinase 2 (CDK2), cyclin E, cyclin A, and downregulation of the expressions of p53, p21, and p-p53. Ginsenoside Rb1 increased glutathione (GSH) and superoxide dismutase (SOD) levels, but decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Pretreatment with ginsenoside Rb1 enhanced the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), total Nrf2, NAD(P)H: quinone oxidoreductases-1 (NQO-1), heme oxygenase-1 (HO-1), and Kelch-like ECH-associated protein 1 (Keap1)/Nrf2 complex. Therefore, ginsenoside Rb1 effectively alleviates TP-induced cytotoxicity in HL-7702 cells through activation of the Keap1/Nrf2/ARE antioxidant pathway.

The role of flavonoids in inhibiting IL-6 and inflammatory arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the synovial joints. RA has well-known clinical manifestations and can cause progressive disability and premature death along with socioeconomic burdens. Interleukin-6 (IL-6) has been implicated in the pathology of RA where it can stimulate pannus formation, osteoclastogenesis, and oxidative stress. Flavonoids are plant metabolites with beneficial pharmacological effects, including anti-inflammatory, antioxidant, antidiabetic, anticancer, and others. Flavonoids are polyphenolic compounds found in a variety of plants, vegetables, and fruits. Many flavonoids have demonstrated anti-arthritic activity mediated mainly through the suppression of pro-inflammatory cytokines. This review thoroughly discusses the accumulate data on the role of flavonoids on IL-6 in RA.

OUP accepted manuscript

Acute lung injury has been reported following various chemotherapeutic agents administration. Several pathways for lung injury have been speculated however, the exact mechanism of the lung injury induced by methotrexate (MTX) is yet to be defined. The potential protective effect of Ginkgo biloba extract (GB), a Chinese herbal medicine, against MTX-induced lung injury is still not reported. Therefore, this study was performed to examine the possible implication of NLRP3 inflammasome and miRNA-21 in the pathogenesis of the MTX-induced lung injury as well as the protective role of GB in ameliorating the induced lung injury. Rats received GB (100 mg/kg/day, orally) for 10 days and MTX (20 mg/kg single dose, intraperitoneally) on the fifth day. MTX-induced lung injury was manifested by lung histopathology. MTX exhibited a marked increase in lung malondialdehyde beside a notable decrease in lung reduced glutathione. Moreover, MTX injection activated the lung NLRP3 inflammasome by significant upregulation of the NLRP3, ASC, caspase-1 lung mRNA expressions and protein levels in addition to lung NF-kBp65 protein expression, and miRNA-21 expression when compared with the normal control group. However, GB administration mitigated lung injury and inhibited the NLRP3 activation. This study is the first report to reveal the involvement of NLRP3 inflammasome in the pathogenesis of MTX-induced lung injury and also to show that the administration of GB alleviates the lung injury induced by MTX via suppressing the oxidative stress, restoring the antioxidant activity, blocking the NLRP3/ASC/Caspase-1 signaling and downregulating the NF-kBp65 protein expression ae well as miRNA-21 expression in lung tissue.

Diosmetin attenuate experimental ulcerative colitis in rats via suppression of NF-κB, TNF-α and IL-6 signalling pathways correlated with down-regulation of apoptotic events

Introduction

Ulcerative colitis (UC) is a chronic inflammation of colon in which the innermost tissue of colon and rectum develops deep-rooted inflammation. Diosmetin is the aglycone of the flavonoid glycoside diosmin, commonly found in citrus fruits. Therapeutically diosmetin is indicated to demonstrate anticancer, antimicrobial, antioxidant, oestrogenic and anti-inflammatory activity.

Methods

In this research, we studied the action of diosmetin on TNBS (2,4,6-trinitrobenzene sulfonic acid)-induced UC in rats. Male Wister rats were anesthetised with pentobarbital and TNBS introduced by performing an enema. Diosmetin treatment was provided through oral gavage for the next 28 days. Animals were sacrificed on the 29th day and colon tissues were collected for further examinations.

Results

Diosmetin treatment decreased colonic ulceration dramatically and decreased the percentage of inflammation in the colonic mucosa. Depletion of the TNBS assisted of superoxide dismutase and catalase was substantially restricted, while lipid peroxidation was recorded in the colonic tissue as malondialdehyde content was also decreased. After treatment with diosmetin, the occurrence of TNF-α, IL-6and NF-κB was considerably lowered and the number of apoptotic cells observed was significantly reduced.

Conclusion

Taken together, these observations demonstrated the potential of diosmetin against ulcer formation and development.

Methyl p‑hydroxycinnamate exerts anti‑inflammatory effects in mouse models of lipopolysaccharide‑induced ARDS

Methyl p-hydroxycinnamate (MH), an esterified derivative of p-Coumaric acid exerts anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Based on these effects, the present study investigated the protective role of MH in a mouse model of LPS-induced acute respiratory distress syndrome (ARDS). The results demonstrated that administration of LPS (5 mg/kg intranasally) markedly increased the neutrophil/macrophage numbers and levels of inflammatory molecules (TNF-α, IL-6, IL-1β and reactive oxygen species) in the bronchoalveolar lavage fluid (BALF) of mice. On histological examination, the presence of inflammatory cells was observed in the lungs of mice administered LPS. LPS also notably upregulated the secretion of monocyte chemoattractant protein-1 and protein content in BALF as well as expression of inducible nitric oxide synthase in the lungs of mice; it also caused activation of p38 mitogen-activated protein kinase (MAPK) and NF-κB signaling. However, MH treatment significantly suppressed LPS-induced upregulation of inflammatory cell recruitment, inflammatory molecule levels and p38MAPK/NF-κB activation, and also led to upregulation of heme oxygenase-1 (HO-1) expression in the lungs of mice. In addition, the ability of MH to induce HO-1 expression was confirmed in RAW264.7 macrophages. Taken together, the findings of the present study indicated that MH may exert protective effects against airway inflammation in ARDS mice by inhibiting inflammatory cell recruitment and the production of inflammatory molecules.

Diosmetin inhibits cell growth and proliferation by regulating the cell cycle and lipid metabolism pathway in hepatocellular carcinoma

Diosmetin (DSM), a newly discovered natural flavonoid, found in citrus plants and olive leaves, has been reported to inhibit the progression of cancer when used as a food supplement. This study aimed to investigate DSM's anti-hepatocellular carcinoma (HCC) properties and possible molecular mechanisms. Hep3B and HCCLM3 cells were selected to evaluate the anti-HCC properties of DSM in vitro. RNA sequencing (RNA-seq) was used to identify the possible molecular targets and pathways. Gas chromatography-mass spectrometry (GC-MS) was used to evaluate the effect of DSM treatment on the primary metabolites of HCCLM3 cells. Tumor xenograft was performed in nude mice to examine the anti-HCC properties of DSM in vivo. The results showed that DSM inhibited the proliferation and migration of HCC cells in vitro in a dose-dependent manner. RNA-seq identified 4459 differentially expressed genes (DEGs) that were highly enriched in the cell cycle pathway. In addition, DSM regulated cell growth by arresting the cell cycle in the G1 phase by decreasing the expression of BCL2, CDK1, and CCND1. Furthermore, metabolomics analysis revealed that DSM interfered with the lipid metabolism pathway of HCC cells by significantly inhibiting the synthesis of metabolites, such as acetic acid, decanoic acid, glycerol, and L-proline. Subcutaneous tumor formation experiments revealed that DSM significantly reduced the tumor volume and weight when compared to the control. Immunohistochemical analysis further revealed that DSM treatment significantly decreased the expression of the proliferative marker KI67. Our findings demonstrated that DSM exhibited antitumor effects on HCC cells by inhibiting cell proliferation via cell cycle arrest and interfering with lipid metabolism.

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

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

Diosmetin Ameliorates Vascular Dysfunction and Remodeling by Modulation of Nrf2/HO-1 and p-JNK/p-NF-κB Expression in Hypertensive Rats

Diosmetin is a citrus flavonoid that has antioxidant and anti-inflammatory effects. This study examined the effect of diosmetin on blood pressure and vascular alterations and its underlying mechanisms in experimentally hypertensive rats. Male Sprague rats were administered Nω-nitro-l-arginine methyl ester L-NAME for five weeks and were given diosmetin at doses of 20 or 40 mg/kg or captopril (5 mg/kg) for two weeks. Diosmetin alleviated hypertension, improved endothelial dysfunction, and suppressed the overactivity of sympathetic nerve-mediated vasoconstriction in aorta and mesentery hypertensive rats (p < 0.05). Increases in plasma and aortic tissue malondialdehyde (MDA) and carotid superoxide generations and reductions of plasma superoxide dismutase, catalase, and nitric oxide in hypertensive rats were ameliorated by diosmetin (p < 0.05). Diosmetin increased the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in hypertensive rats. Furthermore, diosmetin mitigated hypertrophy and collagen accumulation of the aortic wall in L-NAME rats. It exhibited an anti-inflammatory effect by reducing interleukin-6 (IL-6) accumulation and by overexpressing the phospho-c-Jun N-terminal kinases (p-JNK) and the phospho-nuclear factor-kappaB (p-NF-κB) proteins in the aorta (p < 0.05). Captopril was a positive control substance and had similar effects to diosmetin. In summary, diosmetin reduced blood pressure and alleviated vascular abnormalities in L-NAME-treated rats. These effects might be related to antioxidant and anti-inflammatory effects as well as to the modulation of the expression of the Nrf2/HO1 and p-JNK/NF-κB proteins.

Flavonoids as potential phytotherapeutics to combat cytokine storm in SARS-CoV-2

Emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, COVID-19, has become the global panic since December 2019, which urges the global healthcare professionals to identify novel therapeutics to counteract this pandemic. So far, there is no approved treatment available to control this public health issue; however, a few antiviral agents and repurposed drugs support the patients under medical supervision by compromising their adverse effects, especially in emergency conditions. Only a few vaccines have been approved to date. In this context, several plant natural products-based research studies are evidenced to play a crucial role in immunomodulation that can prevent the chances of infection as well as combat the cytokine release storm (CRS) generated during COVID-19 infection. In this present review, we have focused on flavonoids, especially epicatechin, epigallocatechin gallate, hesperidin, naringenin, quercetin, rutin, luteolin, baicalin, diosmin, ge nistein, biochanin A, and silymarin, which can counteract the virus-mediated elevated levels of inflammatory cytokines leading to multiple organ failure. In addition, a comprehensive discussion on available in silico, in vitro, and in vivo findings with critical analysis has also been evaluated, which might pave the way for further development of phytotherapeutics to identify the potential lead candidatetoward effective and safe management of the SARS-CoV-2 disease.

rhKGF-2 Attenuates Smoke Inhalation Lung Injury of Rats via Activating PI3K/Akt/Nrf2 and Repressing FoxO1-NLRP3 Inflammasome

Smoke inhalation injury is an acute pathological change caused by thermal stimulation or toxic substance absorption through respiratory epithelial cells. This study aims to probe the protective effect and mechanism of recombinant human keratinocyte growth factor 2 (rhKGF-2) against smoke inhalation-induced lung injury (SILI) in rats. The SILI was induced in rats using a smoke exposure model, which were then treated with rhKGF-2. The rat blood was collected for blood-gas analysis, and the levels of inflammatory factors and oxidative stress markers in the plasma were measured. The rat lung tissues were collected. The pathological changes and cell apoptosis were determined by hematoxylin-eosin (HE) staining and TdT-mediated dUTP nick end labeling (TUNEL) assay, and the PI3K/Akt/Nrf2/HO-1/NQO1, and FoxO1-NLRP3 inflammasome expression were verified by western blot (WB). Both of the human alveolar epithelial cell (HPAEpiC) and primary rat alveolar epithelial cell were exposed to lipopolysaccharide (LPS) for making in-vitro alveolar epithelial cell injury model. After treatment with rhKGF-2, GSK2126458 (PI3K inhibitor) and AS1842856 (FoxO1 inhibitor), the cell viability, apoptosis, inflammation, oxidative stress, reactive oxygen species (ROS), PI3K/Akt/Nrf2, HO-1/NQO1, and FoxO1-NLRP3 in HPAEpiC and primary rat alveolar epithelial cell were examined. The data suggested that rhKGF-2 reduced LPS-induced HPAEpiC cell and primary rat alveolar epithelial cell apoptosis and the expression of inflammatory factors and oxidative stress factors. Moreover, rhKGF-2 improved the blood gas and alleviated SILI-induced lung histopathological injury in vivo via repressing inflammation, NLRP3 inflammasome activation and oxidative stress. Mechanistically, rhKGF-2 activated PI3K/Akt pathway, enhanced Nrf2/HO-1/NQO1 expression, and attenuated FoxO1-NLRP3 inflammasome both in vitro and in vivo. However, pharmaceutical inhibition of PI3K/Akt pathway attenuated rhKGF-2-mediated protective effects against SILI, while suppressing FoxO1 promoted rhKGF-2-mediated protective effects. Taken together, this study demonstrated that rhKGF-2 mitigated SILI by regulating the PI3K/Akt/Nrf2 pathway and the FoxO1-NLRP3 axis, which provides new reference in treating SILI.

Structure and Function of Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs) and Their Role in Cardiovascular Diseases

Abnormal function of suborganelles such as mitochondria and endoplasmic reticulum often leads to abnormal function of cardiomyocytes or vascular endothelial cells and cardiovascular disease (CVD). Mitochondria-associated membrane (MAM) is involved in several important cellular functions. Increasing evidence shows that MAM is involved in the pathogenesis of CVD. MAM mediates multiple cellular processes, including calcium homeostasis regulation, lipid metabolism, unfolded protein response, ROS, mitochondrial dynamics, autophagy, apoptosis, and inflammation, which are key risk factors for CVD. In this review, we discuss the structure of MAM and MAM-associated proteins, their role in CVD progression, and the potential use of MAM as the therapeutic targets for CVD treatment.

Dasatinib protects against acute respiratory distress syndrome via Nrf2-regulated M2 macrophages polarization

Dasatinib, a tyrosine kinase inhibitor, has a protective effect on experimental acute respiratory distress syndrome (ARDS). This study investigated the effect and mechanism of dasatinib in ARDS. C57BL/6 mice were administered with dasatinib (1 and 10 mg/kg) after lipopolysaccharide (LPS) treatment to evaluate the effect of dasatinib on white blood cells (WBC), neutrophils, lymphocytes and macrophages in bronchoalveolar lavage fluid (BALF). The levels and mRNA expressions of inflammation-related cytokines in lung tissues and RAW 264.7 cells were detected by enzyme-linked immunosorbent assay and quantitative real-time PCR, respectively. The protein expressions of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase 1 (HO1) were determined by Western blot. MTT assay was performed to detect the viability of RAW 264.7 cell. Rescue experiments were used to assess the effect of Nrf2 silencing on the LPS- and dasatinib-treated mice. Under LPS treatment, levels of the WBC, neutrophils, lymphocytes and macrophages in BALF and mRNA expressions of IL-6, TNF-α and IL-10 as well as expression of iNOS were increased, but the expression of arginase-1 was inhibited, while no obvious changes of the protein expressions of Nrf2 and HO1 were observed. Dasatinib partially reversed the effects of LPS above, and further promoted the mRNA expression of IL-10 and the protein expressions of Nrf2 and HO1, while Nrf2 silencing counteracted the effect of dasatinib. Dasatinib induced the polarization of M2 subtype of macrophages and alleviated LPS-induced ARDS through activating Nrf2 signaling pathway, which may provide a new strategy for the treatment of ARDS.

Diosmetin Ameliorates Nonalcoholic Steatohepatitis through Modulating Lipogenesis and Inflammatory Response in a STAT1/CXCL10-Dependent Manner

Nonalcoholic steatohepatitis (NASH) is an inflammatory lipotoxic disorder characterized by lipid accumulation and inflammation. Diosmetin (Dios), a flavonoid, has an active effect against nonalcoholic fatty liver disease, whereas its effect on NASH remains elusive. To investigate the effects of Dios on lipogenesis and inflammatory response and explore the molecular mechanisms of Dios on NASH, mice induced by high-fat diet (HFD), HepG2 cells stimulated by palmitic acid (PA), transcriptome sequencing, and molecular biological experiments were used. We show, by pathological analysis (HE, Oli Red O, and Masson staining) and biochemical parameters (TC, TG, LDL-C, ALT, and AST), Dios alleviated liver lipid accumulation and inflammatory injury. According to liver RNA-Seq analysis, CXCL10 and STAT1 were assumed to be the key target genes of Dios on NASH. Significantly, Dios regulated STAT1/CXCL10 signal pathway and further attenuated NASH via regulating the expression of LXRα/β, SREBP-1c, CHREBP, and NF-κB. In conclusion, Dios is proposed to alleviate NASH through suppression of lipogenesis and inflammatory response via a STAT1/CXCL10-dependent pathway.

Euphorbia cuneata Represses LPS-induced Acute Lung Injury in Mice via its Antioxidative and Anti-inflammatory Activities

Euphorbia cuneata (EC; Euphorbiaceae), which widely grows in Saudi Arabia and Yemen, is used traditionally to treat pain and inflammation. This study aimed to evaluate the protective anti-inflammatory effect of a standardized extract of EC against lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and the possible underlying mechanism(s) of this pharmacologic activity. ALI was induced in male Balb/c mice using intraperitoneal injection of LPS. A standardized total methanol extract of EC or dexamethasone was administered 5 days prior to LPS challenge. Bronchoalveolar fluid (BALF) and lung samples were collected for analysis. The results demonstrated the protective anti-inflammatory effect of EC against LPS-induced ALI in mice. Standardized EC contained 2R-naringenin-7-O-β-glucoside (1), kaempferol-7-O-β-glucoside (2), cuneatannin (3), quercetin (4), and 2R-naringenin (5) in concentrations of 6.16, 4.80, 51.05, 13.20, and 50.00 mg/g of extract, respectively. EC showed a protective effect against LPS-induced pulmonary damage. EC reduced lung wet/dry weight (W/D) ratio and total protein content in BALF, indicating attenuation of the pulmonary edema. Total and differential cell counts were decreased in EC-treated animals. Histopathological examination confirmed the protective effect of EC, as indicated by an amelioration of LPS-induced lesions in lung tissue. EC also showed a potent anti-oxidative property as it decreased lipid peroxidation and increased the antioxidants in lung tissue. Finally, the anti-inflammatory activity of EC was obvious through its ability to suppress the activation of nuclear factor-κB (NF-κB), and hence its reduction of the levels of downstream inflammatory mediators. In conclusion, these results demonstrate the protective effects of EC against LPS-induced lung injury in mice, which may be due to its antioxidative and anti-inflammatory activities.

Diosmetin Induces Apoptosis by Downregulating AKT Phosphorylation via P53 Activation in Human Renal Carcinoma ACHN Cells

Background:

Diosmetin (DIOS) is the aglycone of the flavonoid glycoside, diosmin, derived naturally from the leaves of the legume, Olea europaea, and Acacia farnesiana. It has potent anticancer activity against multiple forms of cancers. However, the role of DIOS in renal carcinoma and its mechanism of action remain unclear.

Objective:

The purpose of this study is to investigate the effect of DIOS on cell viability and apoptosis in renal carcinoma cells and explore the possible mechanism of action.

Methods:

Cell viability, cytotoxicity, caspase activity, apoptosis, and expression of apoptotic related proteins were analyzed in renal carcinoma ACHN cells.

Results:

The results showed that DIOS inhibited the cell viability, and induced cytotoxicity and apoptosis in ACHN cells. Furthermore, DIOS increased expression of p53 mRNA and proteins, and downregulated phosphorylation of the phosphoinositide 3-kinase and protein B kinase (PI3K/AKT). In addition, it was observed that the anticancer effect of DIOS was significantly enhanced by the p53 activator, but inhibited by the p53 inhibitor.

Conclusion:

Our data suggested that DIOS induced apoptosis in renal carcinoma ACHN cells by reducing AKT phosphorylation through p53 upregulation.

Pathogen-associated molecular patterns and extracellular Hsp70 interplay in NLRP3 inflammasome activation in monocytic and bronchial epithelial cellular models of COPD exacerbations

During chronic obstructive pulmonary disease (COPD) exacerbations, interplay between pathogen-associated molecular patterns (PAMPs; e.g. lipopolysaccharide (LPS) and lipoteichoic acid (LTA)) and damage-associated molecular patterns (DAMPs; e.g. extracellular heat shock protein 70 (eHsp70) and adenosine triphosphate (ATP)) might influence patient's outcome. Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome might have a role in dysfunctional immune system in COPD. We hypothesized that LPS, LTA, eHsp70 and their combinations induce NLRP3 inflammasome activation, and we aimed to explore this assumption. We used monocytic (monocyte-derived macrophages (MDMs) and THP-1) and bronchial epithelial cells (NHBE and NCI-H292) to represent systemic and local airway compartments that could be affected in COPD. Bacterial components and eHsp70 stimulated NLRP3 and interleukin (IL)-1β gene expression as well as IL-1β and ATP release from all cells compared to non-treated cells. LDH secretion was induced in cell lines only. eHsp70 had inhibitory (NCI-H292) or stimulatory (NHBE) effects on eATP levels compared to PAMP alone. Regarding NLRP3 inflammasome activation, eHsp70 had mostly antagonistic effects. We demonstrated that bacterial components and eHsp70 activate NLRP3 inflammasome and increase ATP secretion. We suggest that extracellular Hsp70 might modulate immune responses provoked by bacterial infections and affect COPD patients' outcome during acute exacerbations.

PIM2 deletion alleviates lipopolysaccharide (LPS)-induced respiratory distress syndrome (ARDS) by suppressing NLRP3 inflammasome

Inflammation has an essential role in regulating the pathogenesis of acute respiratory distress syndrome (ARDS). The serine/threonine kinase PIM2 is highly expressed in human macrophages, and exhibits regulatory role in inflammatory response. However, its effect on ARDS progression has not been investigated and still remains unclear. In the study, we attempted to investigate the potential of PIM2 during ARDS progression, and to reveal the underlying molecular mechanisms. Here, we found that PIM2 expression was dramatically up-regulated in lipopolysaccharide (LPS)-exposed murine macrophages through a dose- and time-dependent manner. Additionally, we found that PIM2 knockdown greatly alleviated LPS-triggered activation of Caspase-1, interleukin (IL)-1β, NOD-like receptor pyrin domain 3 (NLRP3) and apoptosis-associated speck-like protein (ASC) in macrophages, along with suppressed inflammatory response. Importantly, we identified that PIM2 could directly interact with NLRP3. PIM2 over-expression could further promote LPS-triggered inflammation and NLRP3 inflammasome in macrophages. Furthermore, PIM2 knockout significantly alleviated the severity of ARDS in LPS-challenged mice. Evidently decreased inflammatory response and NLRP3 inflammasome were detected in pulmonary tissues of LPS-treated mice with PIM2 deficiency. Together, our findings demonstrated that PIM2 as a promising therapeutic target for ARDS treatment through regulating NLRP3 inflammasome.

The neuroprotective effect of osthole against chronic sleep deprivation (CSD)-induced memory impairment in rats

AIM

Sleep deprivation (SD) is a frequent health problem in modern society. Osthole (Ost), a natural coumarin, has antioxidant and neuroprotective properties. This study examined the functions of Ost in chronic sleep deprivation (CSD)-induced memory deficits in rats.

MAIN METHODS

The CSD rat model was constructed by applying Sleep Interruption Apparatus (SIA). The protective effect of Ost on memory ability of CSD rats was evaluated through behavioral tests. Modafinil (MOD) was a positive control for investigating the mechanisms underlying the actions of Ost. The oxidative stress changes in the cortex and hippocampus of the rats, histological changes in CA1 region in the hippocampus and the protein expressions of neural plasticity markers were measured. The hippocampal neurons were isolated from rats for evaluating the neuroprotective effects of Ost on glutamate-induced neuron injury in vitro.

KEY FINDINGS

Ost administration significantly enhanced the cognitive performance of CSD rats in the open field test, object location recognition experiment, novel object recognition experiment, and Morris water maze test. Ost could effectively normalize the levels/activities of the antioxidant enzyme system in the cortex and hippocampus. Moreover, Ost administration reversed CSD-induced abnormal state of CA1 neurocytes and the down-regulated expressions of plasticity-related genes in vivo and in vitro. Additionally, Ost also notably up-regulated the expressions of Nrf2 and HO-1 previously down-regulated in CA1 neurocytes of CSD rats and in vitro.

SIGNIFICANCE

Our findings showed that Ost alleviated CSD-induced cognitive deficits, and the activation of the Nrf2/HO-1 pathway might be involved in the neuroprotective action of Ost.

Diosmetin alleviates acute kidney injury by promoting the TUG1/Nrf2/HO-1 pathway in sepsis rats

BACKGROUND

We aimed to study the effects and the underlying mechanisms of Diosmetin (DIOS) in rats with sepsis-induced acute kidney injury (AKI).

METHODS

The AKI model in RMCs was induced using LPS, and the cells were then treated with DIOS. Cell viability, apoptosis, inflammatory response, and antioxidant were measured using MTT, Flow cytometry, ELISA, and Lucigenin assay, respectively. The correlation between TUG1 and Nrf2 was confirmed by RNA pull-down and RNA immunoprecipitation. Real-time quantitative PCR and Western blot were performed to detect the expressions of gene and proteins during the development of AKI. The effects of lncRNA-TUG1 silencing and Nrf2 silencing on cell physiological functions were detected. Moreover, a rat sepsis-induced AKI model followed by Hematoxylin & Eosin (H&E) and immunofluorescence staining were performed.

RESULTS

The experimental concentration of DIOS was determined to be 20 μM. After LPS treatment, the activity of RMCs was decreased, the apoptosis rate, inflammation and oxidative stress damage were increased, moreover, the expression of Nrf2/HO-1 signal axis was inhibited and caspase-3 was activated. However, DIOS significantly reversed these effects caused by LPS treatment, and increased the expression of lncRNA-TUG1, but lncRNA-TUG1 silencing effectively reversed the effects of DIOS. In addition, lncRNA-TUG1 was found to interact with Nrf2. Overexpression of TUG1 could reduce the damage of LPS caused to cell physiological functions, which were reversed by siNrf2. Thus, DIOS treatment could improve the physiological and pathological damages of renal tissues in AKI rats.

CONCLUSION

DIOS may reduce sepsis-induced AKI through enhancing the TUG1/Nrf2/HO-1 pathway.

Diosmetin alleviates hypoxia‑induced myocardial apoptosis by inducing autophagy through AMPK activation

Diosmetin has shown great potential in the control of several diseases. The aim of the present study was to evaluate the role of diosmetin as a candidate agent for the treatment of myocardial infarction which was mainly caused by hypoxia. The model of hypoxia‑injured myocardial cells was established using the H9c2 cell line. Cell viability was determined using Cell Counting Kit‑8, cell apoptosis was determined by Annexin V‑FITC Apoptosis Detection Kit and cleaved caspase‑3 level was assessed by western blot analysis. Autophagy was monitored using a commercial kit, and a well‑established reporter system was used to confirm the role of diosmetin in autophagy. The activity of adenosine 5'‑monophosphate‑activated protein kinase (AMPK) signaling was detected by western blot analysis. Cell viability assay indicated that diosmetin alleviated hypoxia‑induced cell death of H9c2 cells in a dose‑dependent manner. Data of the apoptosis assay revealed that diosmetin reduced the proportion of apoptotic cells in the hypoxia‑injured H9c2 cells. It was also found that the occurrence of autophagy was promoted when hypoxia‑injured cells were treated with diosmetin alone, and results of the western blot analysis revealed that AMPK signaling was activated by diosmetin. Administration of diosmetin together with an inhibitor of autophagy (3‑methyladenine, 3‑MA) or AMPK (Compound C) was able to decrease the diosmetin‑induced autophagy as well as the cytoprotective effects in the hypoxia‑injured cells. Our study concluded that diosmetin exhibits a cytoprotective effect on hypoxia‑injured myocardial cells by inducing autophagy and alleviating apoptosis. AMPK was demonstrated to regulate the observed effects caused by diosmetin. This investigation confirmed diosmetin as a promising drug candidate for myocardial infarction treatment. The present findings regarding the inherent molecular mechanisms involved in the protective effects of diosmetin promote the clinical application of diosmetin.

Aloin suppresses lipopolysaccharide-induced acute lung injury by inhibiting NLRP3/NF-κB via activation of SIRT1 in mice

OBJECTIVE

The purpose of this study was to explore the protective effects and potential mechanisms of aloin on lipopolysaccharide (LPS)-induced acute lung injury (ALI).

METHODS

Mice were pretreatment with aloin 1 h before LPS administration. The number of inflammatory cells and the levels of TNF-α and IL-1β was detected. The lung histopathological changes, wet/dry ratio, MPO activity, GSH, MDA, SOD, and the expression of NF-κB and NLRP3 inflammasome were measured.

RESULTS

The results showed that aloin significantly inhibited the number of total cells, neutrophils, and macrophages, as well as the levels of TNF-α and IL-1β in BALF induced by LPS. In addition, pretreatment with aloin also inhibited LPS-induced lung histopathological injuries, lung wet/dry ratio, MPO activity, and MDA content. The levels of GSH and SOD were decreased by LPS and treatment of aloin could increase the levels of GSH and SOD. To study the protective mechanisms of alion on LPS-induced ALI, the expression of SIRT1, NF-κB and NLRP3 inflammasome were tested. We found that aloin significantly inhibited the activation of NF-κB and NLRP3 inflammasome in ALI induced by LPS. Meanwhile, aloin was found to increase the expression of SIRT1 and inhibition of SIRT1 by EX-527 reversed the protective effects of aloin.

CONCLUSIONS

These results suggest that aloin exerts its protective effects on LPS-induced ALI by activation SIRT1, which subsequently results in the suppression of NF-κB and NLRP3 inflammasome.

Hydrogen attenuates sepsis-associated encephalopathy by NRF2 mediated NLRP3 pathway inactivation

OBJECTIVE

Sepsis-associated encephalopathy (SAE) is a major cause of mortality worldwide. Oxidative stress, inflammatory response and apoptosis participate in the pathogenesis of SAE. Nuclear factor erythroid 2-related factor 2 (Nrf2) and nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) pathway is involved in oxidative stress and inflammatory response. We reported that hydrogen gas protected against sepsis in wild-type (WT) but not Nrf2 knockout (KO) mice. Therefore, it is vital to identify the underlying cause of hydrogen gas treatment of sepsis-associated encephalopathy.

METHODS

SAE was induced in WT and Nrf2 KO mice by cecal ligation and puncture (CLP). As a NLRP3 inflammasome inhibitor, MCC950 (50 mg/kg) was administered by intraperitoneal (i.p.) injection before operation. Hydrogen gas (H₂)-rich saline solution (5 mL/kg) was administered by i.p. injection at 1 h and 6 h after sham and CLP operations. Brain tissue was collected to assess the NLRP3 and Nrf2 pathways by western blotting, reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence.

RESULTS

SAE increased NLRP3 and Nrf2 expression in microglia. MCC950 inhibited SAE-induced NLRP3 expression, interleukin (IL)-1β and IL-18 cytokine release, neuronal apoptosis and mitochondrial dysfunction. SAE increased NLRP3 and caspase-1 expression in WT mice compared to Nrf2 KO mice. Hydrogen increased Nrf2 expression and inhibited the SAE-induced expression of NLRP3, caspase-1, cytokines IL-1β and IL-18, neuronal apoptosis, and mitochondrial dysfunction in WT mice but not Nrf2 KO mice.

CONCLUSION

SAE increased NLRP3 and Nrf2 expression in microglia. Hydrogen alleviated inflammation, neuronal apoptosis and mitochondrial dysfunction via inhibiting Nrf2-mediated NLRP3 pathway.

Inhibition and molecular mechanism of diosmetin against xanthine oxidase by multiple spectroscopies and molecular docking

Studying the inhibition and molecular mechanism of diosmetin against xanthine oxidase helps to develop natural product xanthine oxidase inhibitors.

Diosmetin exhibits anti-proliferative and anti-inflammatory effects on TNF-α-stimulated human rheumatoid arthritis fibroblast-like synoviocytes through regulating the Akt and NF-κB signaling pathways

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation and proliferation of synovial tissues. Diosmetin is a bioflavonoid possessing an anti-inflammatory property. Herein, we aimed to study the effects of diosmetin on the inflammation and proliferation of RA fibroblast-like synoviocytes MH7A cells. MH7A cell proliferation was measured using cell counting kit-8 assay. Cell apoptosis was examined using flow cytometry. The production of inflammatory cytokines including interleukin (IL)-1β, IL-6, IL-8, and matrix metalloproteinase-1 (MMP-1) was measured using enzyme-linked immunosorbent assay (ELISA). Results showed that diosmetin inhibited tumor necrosis factor-α (TNF-α)-induced proliferation increase in MH7A cells in a dose-dependent manner. Diosmetin treatment resulted in an increase in apoptotic rates and a reduction in TNF-α-induced production of IL-1β, IL-6, IL-8, and MMP-1 in MH7A cells. Furthermore, diosmetin inhibited TNF-α-induced activation of protein kinase B (Akt) and nuclear factor-κB (NF-κB) pathways in MH7A cells. Suppression of Akt or NF-κB promoted apoptosis and inhibited TNF-α-induced proliferation increase and production of IL-1β, IL-6, IL-8, and MMP-1 in MH7A cells, and diosmetin treatment enhanced these effects. Taken together, these findings suggested that diosmetin exhibited anti-proliferative and anti-inflammatory effects via inhibiting the Akt and NF-κB pathways in MH7A cells.

Inhibition of PRMT5 Attenuates Oxidative Stress-Induced Pyroptosis via Activation of the Nrf2/HO-1 Signal Pathway in a Mouse Model of Renal Ischemia-Reperfusion Injury

Background

Extensive evidence has demonstrated that oxidative stress, pyroptosis, and proinflammatory programmed cell death are related to renal ischemia/reperfusion (I/R) injury. However, the underlying mechanism remains to be illustrated. Protein arginine methylation transferase 5 (PRMT5), which mediates arginine methylation involved in the regulation of epigenetics, exhibits a variety of biological functions and essential roles in diseases. The present study investigated the role of PRMT5 in oxidative stress and pyroptosis induced by I/R injury in a mouse model and in a hypoxia/reoxygenation (H/R) model of HK-2 cells.

Methods

C57 mice were used as an animal model. All mice underwent right nephrectomy, and the left renal pedicles were either clamped or not. Renal I/R injury was induced by ligating the left renal pedicle for 30 min followed by reperfusion for 24 h. HK-2 cells were exposed to normal conditions or stimulation through H/R. EPZ015666(EPZ)—a selective potent chemical inhibitor—and small interfering RNA (siRNA) were administered to suppress the function and expression of PRMT5. The levels of urea nitrogen and creatinine in the serum and renal tissue injury were assessed. Immunohistochemistry, western blotting, and reverse transcription-polymerase chain reaction were used to evaluate pyroptosis-related proteins including nod-like receptor protein-3, ASC, caspase-1, caspase-11, GSDMD-N, and interleukin-1β. Cell apoptosis and cell viability were detected through flow cytometry, and the levels of reactive oxygen species (ROS) and hydrogen peroxide (H₂O₂) were measured. Ki-67 was used to assess the proliferation of renal tubular epithelium. In addition, the activity of malondialdehyde and superoxide dismutase was determined.

Results

I/R or H/R induced an increase in the expression of PRMT5. Inhibition of PRMT5 by EPZ alleviated oxidative stress and I/R- or H/R-induced pyroptosis. In renal tissue, the application of EPZ promoted the proliferation of tubular epithelium. In addition, H/R-induced pyroptosis in HK-2 cells was dependent on oxidative stress in vitro. Administration of either EPZ or siRNA led to decreased expression of pyroptosis-related proteins. Inhibition of PRMT5 also attenuated the I/R- or H/R-induced oxidative stress in vivo and in HK-2 cells, respectively. It also resulted in a distinct decrease in the levels of malondialdehyde and H₂O₂, and an apparent increase in superoxide dismutase activity in mouse renal tissue. Moreover, it led to a significant decrease in the levels of ROS and H₂O₂ in HK-2 cells. When activated, NF-E2-related factor/heme oxygenase-1 (Nrf2/HO-1)—a key regulator of various cytoprotective proteins that withstand oxidative damage—can decrease the generation of ROS. Nrf2/HO-1 was downregulated during I/R in tissues and H/R in HK-2 cells, and this effect was reversed by the PRMT5 inhibitor. Furthermore, the expressions of Nrf2 and HO-1 proteins were markedly upregulated by EPZ or siRNA against PRMT5.

Conclusion

PRMT5 is involved in ischemia- and hypoxia-induced oxidative stress and pyroptosis in vitro and in vivo. Inhibition of PRMT5 may ameliorate renal I/R injury by suppressing oxidative stress and pyroptosis via the activation of the Nrf2/HO-1 pathway, as well as promoting the proliferation of tubular epithelium. Therefore, PRMT5 may be a promising therapeutic target.

NLRP3 Inflammasome Activation by MicroRNA-495 Promoter Methylation May Contribute to the Progression of Acute Lung Injury

Acute lung injury (ALI) is a pulmonary disorder that causes acute respiratory failure, thus leading to relative high mortality worldwide. However, the molecular mechanisms of ALI remain largely unknown. MicroRNA (miRNA)-dependent control of gene expression at a post-transcriptional level has been recently reported. Herein, we identify a candidate miRNA, miR-495, that affects the progression of ALI. Alveolar macrophages (NR8383) were treated with 1 μg/mL lipopolysaccharide (LPS) to establish a cell-injury model. Combined with the data from western blot, methylation-specific PCR, methylated DNA immunoprecipitation, and chromatin immunoprecipitation assays, NLRP3 inflammasome activation and methylation-dependent repression of miR-495 were found in LPS-exposed NR8383 cells. Dual-luciferase reporter gene assay and miR-495 gain-of-function experiments confirmed that NLRP3 was a target of miR-495. Next, the expression of miR-495 and NLRP3 was overexpressed or silenced to assess their effects on NLRP3 inflammasome activation, alveolar macrophage inflammation, and pyroptosis in vitro. As demonstrated, overexpressed miR-495 alleviated alveolar macrophage inflammation and pyroptosis and inhibited NLRP3 inflammasome activation by negatively regulating the NLRP3 gene. Consistently, elevated miR-495 alleviated lung injury and reduced the neutrophil infiltration and inflammation in rat models of LPS-induced ALI. Taken together, the data in our study demonstrated that methylation of the miR-495 promoter could downregulate miR-495, whose elevation could attenuate the activation of the NLRP3 inflammasome to protect against ALI, which provides novel therapeutic targets for ALI treatment.

Hydrogen alleviates mitochondrial dysfunction and organ damage via autophagy‑mediated NLRP3 inflammasome inactivation in sepsis

Sepsis is a highly heterogeneous syndrome that is caused by a dysregulated host response to infection. The disproportionate inflammatory response to invasive infection is a triggering event inducing sepsis. The activation of inflammasomes in sepsis can amplify inflammatory responses. It has been reported that damaged mitochondria contribute to NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome-related sepsis. Our previous study revealed that hydrogen (H₂) exerts anti-inflammatory effects in sepsis but the detailed mechanism remains to be elucidated. In the present study, septic mice induced by cecal ligation and puncture (CLP) and macrophages induced by lipopolysaccha-ride (LPS) were used as models of sepsis in vivo and in vitro, respectively. An inducer and inhibitor of autophagy and the NLRP3 inflammasome were administered to investigate the detailed mechanism of action of H₂ treatment in sepsis. The results demonstrated that LPS and ATP led to NLRP3 inflammasome pathway activation, excessive cytokine release, mitochondrial dysfunction and the activation of autophagy. CLP induced organ injury and NLRP3 pathway activation. H₂ treatment ameliorated vital organ damage, the inflammatory response, mitochondrial dysfunction and NLRP3 pathway activation, and promoted autophagy in macrophages induced by LPS and in CLP mice. However, the inhibitor of autophagy and the inducer of NLRP3 reversed the protective effect of H₂ against organ damage, the inflammatory response and mitochondrial dysfunction in vivo and in vitro. Collectively, the results demonstrated that H₂ alleviated mitochondrial dysfunction and cytokine release via autophagy-mediated NLRP3 inflammasome inactivation.

Diosmetin induces apoptosis and enhances the chemotherapeutic efficacy of paclitaxel in non-small cell lung cancer cells via Nrf2 inhibition

BACKGROUND AND PURPOSE

Non-small-cell lung cancer (NSCLC) accounts for up to 80-85% of all lung cancers and has a disappointing prognosis. Flavonoids exert anticancer properties, mostly involving stimulation of ROS production without significant toxicity to normal cells. This study was aimed to delineate the effect of diosmetin, a natural flavonoid, on NSCLC cells and its ability to enhance the antitumour activity of paclitaxel.

EXPERIMENTAL APPROACH

NSCLC cells, normal cell lines HLF-1 and BEAS-2B, and immunodeficient mice were chosen as models to study the effects of diosmetin. Changes in cell viability, apoptosis, and ROS were analysed by MTT assay, flow cytometry assay, and fluorescent probe DCFH-DA. Expression of proteins and mRNA was determined by Western blotting and real-time RT-PCR. Growth of xenografted tumours was measured. Spleens and other vital organs were analysed with histological and immunohistochemical techniques.

KEY RESULTS

Diosmetin induced selective apoptotic death in NSCLC cells but spared normal cells, via ROS accumulation. Diosmetin induced ROS production in NSCLC cells probably via reducing Nrf2 stability through disruption of the PI3K/Akt/GSK-3β pathway. The in vitro and in vivo xenograft studies showed that combined treatment of diosmetin and paclitaxel synergistically suppressed NSCLC cells. Histological analysis of vital organs showed no obvious toxicity of diosmetin, which matched our in vitro findings.

CONCLUSIONS AND IMPLICATIONS

Diosmetin selectively induced apoptosis and enhanced the efficacy of paclitaxel in NSCLC cells via ROS accumulation through disruption of the PI3K/Akt/GSK-3β/Nrf2 pathway. Therefore, diosmetin may be a promising candidate for adjuvant treatment of NSCLC.