Fraxin ameliorates lipopolysaccharide-induced acute lung injury in mice by inhibiting the NF-κB and NLRP3 signalling pathways

Coumarins as versatile therapeutic phytomolecules: A systematic review

BACKGROUND

Coumarins, abundantly distributed in a plethora of biologically active compounds, serve as a fundamental motif in numerous natural products, drugs, and therapeutic leads. Despite their small size, they exhibit a diverse range of biological activities, intriguing researchers with their immense pharmacological potential.

PURPOSE

This study consolidates the evidence regarding the essential role of coumarins in modern drug discovery, exploring their broad-spectrum pharmaceutical effects, structural versatility, and mechanisms of action across various domains.

METHODS

For literature search, we utilized PubMed, Google scholar, and SciFinder databases. Keyword and keyword combinations such as "coumarins", "natural coumarins", "specific natural coumarins for particular diseases", and "therapeutic effects" were employed to retrieve relevant studies. The search encompassed articles published between 2005 and 2023. Selection criteria included studies reporting on the pharmacological activities of natural coumarins against various diseases.

RESULTS

The results highlight the therapeutic potential of natural coumarins against various diseases, demonstrating anti-cancer, anti-oxidant, and anti-inflammatory activities. They also act as monoamine oxidase inhibitors and phosphodiesterase inhibitors, and as anti-thrombotic, anti-diabetic, and hepatoprotective agents. They also show efficacy against diabetic nephropathy, neurodegenerative diseases, microbial infections and many other diseases.

CONCLUSION

This review underscores the significant role of natural coumarins in medicinal chemistry and drug discovery. Their diverse biological activities and structural versatility make them promising therapeutic agents. This study serves as a catalyst for further research in the field, aiming to address emerging challenges and opportunities in drug development.

Delay the progression of glucocorticoid-induced osteoporosis: Fraxin targets ferroptosis via the Nrf2/GPX4 pathway

Glucocorticoid-induced osteoporosis (GIOP) commonly accelerates bone loss, increasing the risk of fractures and osteonecrosis more significantly than traditional menopausal osteoporosis. The extracellular environment influenced by glucocorticoids heightens fracture and osteonecrosis risks. Fraxin (Fra), a key component of the traditional Chinese herbal remedy Cortex Fraxini, is known for its wide-ranging pharmacological effects, but its impact on GIOP remains unexplored. This investigation aims to delineate the effects and underlying mechanisms of Fra in combating dexamethasone (Dex)-induced ferroptosis and GIOP. We established a mouse model of GIOP via intraperitoneal injections of Dex and cultured osteoblasts with Dex treatment for in vitro analysis. We evaluated the impact of Fra on Dex-treated osteoblasts through assays such as C11-BODIPY and FerroOrange staining, mitochondrial functionality tests, and protein expression analyses via Western blot and immunofluorescence. The influence of Fra on bone microarchitecture of GIOP in mice was assessed using microcomputerized tomography, hematoxylin and eosin staining, double-labeling with Calcein-Alizarin Red S, and immunohistochemistry at imaging and histological levels. Based on our data, Fra prevented Dex-induced ferroptosis and bone loss. In vitro, glutathione levels increased and malondialdehyde, lipid peroxidation, and mitochondrial reactive oxygen species decreased. Fra treatment also increases nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4), and COL1A1 expression and promotes bone formation. To delve deeper into the mechanism, the findings revealed that Fra triggered the activation of Nrf2/GPX4 signaling. Moreover, the use of siRNA-Nrf2 blocked the beneficial effect of Fra in osteoblasts cultivated with Dex. Fra effectively combats GIOP by activating the Nrf2/GPX4 signaling pathway to inhibit ferroptosis.

Fraxin alleviates oral lichen planus by suppressing OCT3-mediated activation of FGF2/NF-κB pathway

Oral lichen planus (OLP) is a carcinogenic chronic inflammatory oral disease, which lacks effective treatments. Fraxin is an active ingredient of the traditional Chinese medicine Qin Pi, which has an anti-inflammatory effect, but its effect on OLP is unclear. The aim of this study was to investigate the therapeutic effect of fraxin on OLP and the underlying mechanism. Human immortalized keratinocytes (HaCat) were incubated with fraxin (10, 20, or 40 µM) for 48 h and then treated with 10 µg/mL LPS for 24 h. Cell viability and apoptosis were detected. Next, the interaction between OCT3 and FGF2 was predicted by online database and verified by Co-IP analysis. Fraxin, Ad-OCT3, sh-OCT3, and sh-FGF2 were, respectively, applied to treat LPS-incubated HaCat cells, and cell viability, apoptosis, and secretion of inflammatory factors were detected with MTT, flow cytometry, and ELISA assays. Then, the involvement of OCT3 and FGF2 in the prevention of fraxin on HaCat cells from LPS-induced cell apoptosis and inflammation was investigated through multiple rescue experiments. In addition, OLP models were constructed in VDR-/- mice and NOD/SCID mice by injecting with human OLP pathological tissue homogenates to verify the therapeutic effect of fraxin on OLP. Fraxin treatment increased cell viability and reduced cell apoptosis and the secretion of IL-6 and TNF-α in a dose-dependent manner. OCT3 was significantly upregulated in oral mucosa tissues of OLP mice. OCT3 silencing inhibited LPS-induced cell apoptosis and secretion of inflammatory factors. Fraxin incubation reduced the expression of OCT3, and OCT3 interacted with FGF2 to upregulate FGF2 protein. FGF2 silencing reduced the expression of p-p65/NF-κB protein and improved LPS-induced cell apoptosis and secretion of inflammatory factors. OCT3 overexpression increased the expression of FGF2 and p-p65/NF-κB proteins, rh-FGF2 aggravated this effect, while FGF2-Neu-Ab reversed this effect. The results of in vivo experiments showed that fraxin alleviated cell apoptosis and inflammation in oral buccal mucosa tissues of OLP mice. Fraxin inhibited cell apoptosis and inflammation by suppressing OCT3-mediated activation of the FGF2/NF-κB pathway, alleviating the progression of OLP.

Fraxini cortex: Progresses in phytochemistry, pharmacology and ethnomedicinal uses

ETHNOPHARMACOLOGICAL RELEVANCE

Fraxini cortex, which has been widely used as a traditional Chinese medicine for 2000 years, is made from the dried bark of four plant species: Fraxinus chinensis subsp. rhynchophylla (Hance) A.E.Murray, Fraxinus chinensis Roxb., Fraxinus chinensis subsp. chinensis and Fraxinus stylosa Lingelsh.. In Chinese traditional medicine, it possesses the properties of heat-clearing and dampness-drying, asthma relief and cough suppression, as well as vision improvement. It is utilized for treating bacterial disorders, enteritis, leukorrhea, chronic bronitis, painful red eyes with swelling, lacrimation due to windward exposure, psoriasis, and other diseases or related symptoms.

AIM OF THE STUDY

Fraxini cortex is abundant in chemical constituents and has garnered significant attention from plant chemists, particularly regarding coumarins, as evidenced by the recently identified three coumarin compounds. Considering the current dearth of systematic reporting on studies pertaining to Fraxini cortex, herein we provide a comprehensive summary of the advancements in phytochemistry, pharmacology, detection methods, and ethnomedicinal applications of Fraxini cortex.

MATERIALS AND METHODS

We conducted a comprehensive search across online data sources (Web of Science, Public Medicine (PubMed), China National Knowledge Infrastructure (CNKI), as well as Chinese dissertations) and traditional Chinese medicine classics to gather the necessary literature resources for this review.

RESULTS

Briefly, The Fraxini cortex yielded a total of 132 phytochemicals, including coumarins, lignans, secoiridoids, phenylethanol glycosides, flavonoids, triterpenoids, and other compounds. Among them, the main active ingredients are coumarins which possess a diverse range of pharmacological activities such as anti-inflammatory effects, anti-tumor properties, prevention of tissue fibrosis and oxidation damage as well as cardioprotective effects.

CONCLUSIONS

All types of research conducted on Fraxini cortex, particularly in the field of ethnopharmacology, phytochemistry, and pharmacology, have been thoroughly reviewed. However, certain traditional applications and pharmacological activities of Fraxini cortex lack scientific evaluation or convincing evidence due to incomplete methodologies and ambiguous results, as well as a lack of clinical data. To validate its pharmacological activity, clinical efficacy, and safety profile, a systematic and comprehensive research evaluation is imperative. As an important traditional Chinese medicine, Fraxini cortex should be further explored to facilitate the development of novel drugs and therapeutics for various diseases. Greater attention should be given to how it can be better utilized.

Pharmacological Activities of Plant-Derived Fraxin with Molecular Mechanisms: A Comprehensive Review

Fruits and vegetables serve not only as sources of nutrition but also as medicinal agents for the treatment of diverse diseases and maladies. These dietary components are significant resources of phytochemicals that demonstrate therapeutic properties against many illnesses. Fraxin is a naturally occurring coumarin glycoside mainly present in various species of Fraxinus genera, having a multitude of therapeutic uses against various diseases and disorders. This study focuses to investigate the pharmacological activities, botanical sources, and biopharmaceutical profile of the phytochemical fraxin based on different preclinical and non-clinical studies to show the scientific evidence and to evaluate the underlying molecular mechanisms of the therapeutic effects against various ailments. For this, data was searched and collected (as of February 15, 2024) in a variety of credible electronic databases, including PubMed/Medline, Scopus, Springer Link, ScienceDirect, Wiley Online, Web of Science, and Google Scholar. The findings demonstrated favorable outcomes in relation to a range of diseases or medical conditions, including inflammation, neurodegenerative disorders such as cerebral ischemia-reperfusion (I/R) and depression, viral infection, as well as diabetic nephropathy. The phytochemical also showed protective effects such as osteoprotective, renoprotective, pulmoprotective, hepatoprotective, and gastroprotective effects due to its antioxidant capacity. Fraxin has a great capability to diminish oxidative stress-related damage in different organs by stimulating the antioxidant enzymes, downregulating nuclear factor kappa B and NLRP3, and triggering the Nrf2/ARE signaling pathways. Fraxin exhibited poor oral bioavailability because of reduced absorption and a wide distribution into tissues of different organs. However, extensive research is required to decipher the biopharmaceutical profiles, and clinical studies are necessary to establish the efficacy of the natural compound as a reliable therapeutic agent.

Anti-cytokine Storm Activity of Fraxin, Quercetin, and their Combination on Lipopolysaccharide-Induced Cytokine Storm in Mice: Implications in COVID-19

Background

Cytokine release syndrome (CRS) is the leading cause of mortality in advanced stages of coronavirus patients. This study examined the prophylactic effects of fraxin, quercetin, and a combination of fraxin+quercetin (FQ) on lipopolysaccharide-induced mice.

Methods

Sixty mice were divided into six groups (n=10) as follows: control, LPS only, fraxin (120 mg/Kg), quercetin (100 mg/Kg), dexamethasone (5 mg/Kg), and FQ. All treatments were administered intraperitoneally (IP) one hour before induction by LPS (5 mg/Kg) IP injection. Twenty-four hours later, the mice were euthanized. Interleukin one beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were quantified using an enzyme-linked immunosorbent assay (ELISA), and lung and kidney tissues were examined for histopathological alterations. This study was conducted at Al-Nahrain University, Baghdad, Iraq, in 2022.

Results

FQ reduced IL-1β (P<0.001). All treatments significantly suppressed IL-6, fraxin, quercetin, dexamethasone, and FQ, all with P<0.001. The TNF-α level was reduced more with dexamethasone (P<0.001) and quercetin (P<0.001). Histopathological scores were significantly reduced mainly by quercetin and FQ in the lungs with scores of 12.30±0.20 (P=0.093), and 15.70±0.20 (P=0.531), respectively. The scores were 13±0.26 (P=0.074) and 15±0.26 (P=0.222) for quercetin and FQ in the kidneys, respectively.

Conclusion

All used treatments reduced proinflammatory cytokine levels and protected against LPS-induced tissue damage.

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.

Fraxin (7-hydroxy-6-methoxycoumarin 8-glucoside) confers protection against ionizing radiation-induced intestinal epithelial injury in vitro and in vivo

The small intestine exhibits remarkable sensitivity to ionizing radiation (IR), which significantly hampers the effectiveness of radiotherapy in the treatment of abdominal and pelvic tumors. Unfortunately, no effective medications are available to treat radiation-induced intestinal damage (RIID). Fraxin (7-hydroxy-6-methoxycoumarin 8-glucoside), is a coumarin derivative extracted from the Chinese herb Cortex Fraxini. Several studies have underscored the anti-inflammatory, antibacterial, antioxidant, and immunomodulatory properties of fraxin. However, the efficacy of fraxin at preventing or mitigating RIID remains unclear. Thus, the present study aimed to investigate the protective effects of fraxin against RIID in vitro and in vivo and to elucidate the underlying mechanisms. The study findings revealed that fraxin markedly ameliorated intestinal injuries induced by 13 Gy whole abdominal irradiation (WAI), which was accompanied by a significant increase in the population of Lgr5+ intestinal stem cells (ISCs) and Ki67+ progeny. Furthermore, fraxin mitigated WAI-induced intestinal barrier damage, and reduced oxidative stress and intestinal inflammation in mice. Transcriptome sequencing of fraxin-treated mice revealed upregulation of IL-22, a pleiotropic cytokine involved in regulating the function of intestinal epithelial cells. Moreover, in both human intestinal epithelial cells and ex vivo cultured mouse intestinal organoids, fraxin effectively ameliorated IR-induced damage by promoting the expression of IL-22. The radioprotective effects of fraxin were partially negated in the presence of an IL-22-neutralizing antibody. In summary, fraxin is demonstrated to possess the ability to alleviate RIID and maintain intestinal homeostasis, suggesting that fraxin might serve as a strategy for mitigating accidental radiation exposure- or radiotherapy-induced RIID.

Fraxin represses NF-κB pathway via inhibiting the activation of epidermal growth factor receptor to ameliorate diabetic renal tubulointerstitial fibrosis

Renal tubulointerstitial fibrosis (RIF), featured by epithelial-to-mesenchymal-transition (EMT) of renal tubular epithelial cells and collagen deposition in the renal interstitial region, is the main pathological change of diabetic nephropathy (DN). Fraxin, the main active component of Fraxinus rhynchophylla Hance with anti-inflammatory activity, has been demonstrated to ameliorate glomerulosclerosis. However, the regulatory role of Fraxin on diabetic RIF remains unclear. In this study, we investigated the renal protective benefits of Fraxin against diabetic RIF and elucidated its mechanisms. In vitro, Fraxin inhibited the abnormal expression of EMT-related markers and proinflammatory cytokines, improved cellular morphology, and subsequently reduced the extracellular matrix (ECM) production in high glucose (HG)-induced NRK-52E cells. In vivo, Fraxin effectively ameliorated renal function, inhibited the abnormal expression of EMT-related markers and proinflammatory cytokines, and reduced ECM deposition in renal tubule interstitium in db/db mice. Notably, Fraxin could directly bind to epidermal growth factor receptor (EGFR), which contributed to the inhibition of EGFR phosphorylation and counteracted the activation of c-Src/NF-κB pathway, eventually ameliorating RIF. Thus, Fraxin may be a potential drug candidate for treating DN.

Sepsis-Induced Acute Lung Injury Is Alleviated by Small Molecules from Dietary Plants via Pyroptosis Modulation

Sepsis-induced acute respiratory distress syndrome (ARDS) has high morbidity and mortality, and it has three major pathogeneses, namely alveolar-capillary barrier destruction, elevated gut permeability, and reduced neutrophil extracellular traps (NETS), all of which are pyroptosis-involved. Due to limitations of current agents like adverse reaction superposition, inevitable drug resistance, and relatively heavier financial burden, naturally extracted small-molecule compounds have a broad market even though chemically modified drugs have straightforward efficacy. Despite increased understanding of the molecular biology and mechanism underlying sepsis-induced ARDS, there are no specific reviews concerning how small molecules from dietary plants alleviate sepsis-induced acute lung injury (ALI) via regulating pyroptotic cell death. Herein, we traced and reviewed the molecular underpinnings of sepsis-induced ALI with a focus on small-molecule compounds from dietary plants, the top three categories of which are respectively flavonoids and flavone, terpenoids, and polyphenol and phenolic acids, and how they rescued septic ALI by restraining pyroptosis.

Deciphering the pharmacological mechanisms of Fraxini Cortex for ulcerative colitis treatment based on network pharmacology and in vivo studies

BACKGROUND

Ulcerative colitis (UC) is a common type of inflammatory bowel disease. Due to the elusive pathogenesis, safe and effective treatment strategies are still lacking. Fraxini Cortex (FC) has been widely used as a medicinal herb to treat some diseases. However, the pharmacological mechanisms of FC for UC treatment are still unclear.

METHODS

An integrated platform combining network pharmacology and experimental studies was introduced to decipher the mechanism of FC against UC. The active compounds, therapeutic targets, and the molecular mechanism of action were acquired by network pharmacology, and the interaction between the compounds and target proteins were verified by molecular docking. Dextran sulfate sodium (DSS)-induced colitis model was employed to assess the therapeutic effect of FC on UC, and validate the molecular mechanisms of action predicted by network pharmacology.

RESULTS

A total of 20 bioactive compounds were retrieved, and 115 targets were predicted by using the online databases. Ursolic acid, fraxetin, beta-sitosterol, and esculetin were identified as the main active compounds of FC against UC. PPI network analysis identified 28 FC-UC hub genes that were mainly enriched in the IL-17 signaling pathway, the TNF signaling pathway, and pathways in cancer. Molecular docking confirmed that the active compounds had high binding affinities to the predicted target proteins. GEO dataset analysis showed that these target genes were highly expressed in the UC clinical samples compared with that in the healthy controls. Experimental studies showed that FC alleviated DSS-induced colitis symptoms, reduced inflammatory cytokines release, and suppressed the expression levels of IL1β, COX2, MMP3, IL-17 and RORγt in colon tissues.

CONCLUSION

FC exhibits anti-UC properties through regulating multi-targets and multi-pathways with multi-components. In vivo results demonstrated that FC alleviated DSS-induced colitis.

The pharmacological properties and corresponding mechanisms of farrerol: a comprehensive review

CONTEXT

Farrerol, a typical natural flavanone isolated from the traditional Chinese herb 'Man-shan-hong' [Rhododendron dauricum L. (Ericaceae)] with phlegm-reducing and cough-relieving properties, is widely used in China for treating bronchitis and asthma.

OBJECTIVE

To present the anti-inflammatory, antioxidant, vasoactive, antitumor, and antimicrobial effects of farrerol and its underlying molecular mechanisms.

METHODS

The literature was reviewed by searching PubMed, Medline, Web of Knowledge, Scopus, and Google Scholar databases between 2011 and May 2021. The following key words were used: 'farrerol,' 'flavanone,' 'anti-inflammatory,' 'antioxidant,' 'vasoactive,' 'antitumor,' 'antimicrobial,' and 'molecular mechanisms'.

RESULTS

Farrerol showed anti-inflammatory effects mainly mediated via the inhibition of interleukin (IL)-6/8, IL-1β, tumour necrosis factor(TNF)-α, NF-κB, NO, COX-2, JNK1/2, AKT, PI3K, ERK1/2, p38, Keap-1, and TGF-1β. Farrerol exhibited antioxidant effects by decreasing JNK, MDA, ROS, NOX4, Bax/Bcl-2, caspase-3, p-p38 MAPK, and GSK-3β levels and enhancing Nrf2, GSH, SOD, GSH-Px, HO-1, NQO1, and p-ERK levels. The vasoactive effects of farrerol were also shown by the reduced α-SMA, NAD(P)H, p-ERK, p-Akt, mTOR, Jak2, Stat3, Bcl-2, and p38 levels, but increased OPN, occludin, ZO-1, eNOS, CaM, IP3R, and PLC levels. The antitumor effects of farrerol were evident from the reduced Bcl-2, Slug, Zeb-1, and vimentin levels but increased p27, ERK1/2, p38, caspase-9, Bax, and E-cadherin levels. Farrerol reduced α-toxin levels and increased NO production and NF-κB activity to impart antibacterial activity.

CONCLUSIONS

This review article provides a theoretical basis for further studies on farrerol, with a view to develop and utilise farrerol for treating of vascular-related diseases in the future.

Protective effects of fraxin on cerebral ischemia-reperfusion injury by mediating neuroinflammation and oxidative stress through PPAR-γ/NF-κB pathway

BACKGROUND

Inflammation and oxidative stress are associated with the pathogenesis of cerebral ischemia-reperfusion (I/R) injury. Fraxin, one of the primary active ingredients of Cortex Fraxini, may have potent anti-inflammatory activity. This study intended to investigate the function and mechanism of fraxin in a middle cerebral artery occlusion (MCAO) model.

METHODS

A middle cerebral artery occlusion (MCAO) rat model was engineered. Both in-vivo and in-vitro models were dealt with Fraxin. The profiles of inflammation-concerned cytokines, proteins and oxidative stress factors were determined by RT-PCR, western blot, and enzyme-linked immunosorbent assay (ELISA), and neuronal apoptosis and reactive oxygen species (ROS) levels were measured. The neurological functions of rats were evaluated by Morris water maze and modified neurological severity scores (mNSS).

RESULTS

The data revealed that fraxin abated the OGD/R-mediated release of inflammatory and oxidative stress mediators, enhanced "M2″-like BV2 microglia polarization, and mitigated HT22 cell apoptosis. Mechanistically, fraxin boosted PPAR-γ expression, activated the Nrf2/HO-1 pathway, and suppressed NF-κB, IKK-β，p38 MAPK, ERK1/2 and Keap1 in a dose-dependent manner. Furthermore, attenuating PPAR-γ through pharmacological treatment with GW9662 (a PPAR-γ antagonist) mainly weakened the neuroprotective and anti-inflammatory functions of fraxin.

CONCLUSION

Fraxin could considerably ameliorate cerebral I/R damage by repressing oxidative stress, inflammatory response, and cell apoptosis through abrogating the PPARγ/ NF-κB pathway.

Semaglutide ameliorates lipopolysaccharide-induced acute lung injury through inhibiting HDAC5-mediated activation of NF-κB signaling pathway

BACKGROUND

As a life-threatening respiratory syndrome, acute lung injury (ALI) is characterized by uncontrollable inflammatory activities. Semaglutide (SEM) has been identified as an effective anti-inflammatory drug in a variety of diseases. This study intended to explore the functional effect and potential mechanisms of SEM in ALI.

METHODS

Lipopolysaccharide (LPS) was used to construct an in vivo ALI model based on Sprague-Dawley (SD) rats and an in vitro ALI model based on human pulmonary artery endothelial cells (HPAECs). Hematoxylin & eosin (H&E) staining and ELISA were applied to evaluate the histopathological changes in pulmonary tissues and detect TNF-α and IL-6 levels. RT-qPCR and Western blotting were used to measure gene and protein expressions in pulmonary tissues and cells. HPAEC viability and apoptosis were evaluated by CCK-8 method and flow cytometry methods.

RESULTS

Semaglutide pretreatment significantly mitigated pulmonary injury, reduced TNF-α and IL-6 production, and led to a decrease in cleaved caspase-3 level and an increase in Bcl-2 level, suggesting SEM could ameliorate LPS-induced ALI in rats. In vitro, SEM increased the proliferative capability and mitigated inflammation and apoptosis in LPS-stimulated HPAECs. In addition, SEM inhibited HDAC5-mediated NF-κB signaling pathway in HPAECs. HDAC5 overexpression or NF-κB signaling activation could partly impair SEM-mediated protective effects against LPS-induced damage to HPAECs.

CONCLUSION

Semaglutide restrains LPS-induced ALI by inhibiting HDAC5/NF-κB signaling pathway.

FBW7 protects against spinal cord injury by mitigating inflammation-associated neuronal apoptosis in mice

Spinal cord injury (SCI) leads to severe and long-lasting neurological disability. Presently, the lack of effective therapies for SCI is largely attributable to an incomplete understanding of its pathogenesis. F-box and WD repeat domain-containing protein 7 (FBW7, also known as FBXW7) is a type of E3 ubiquitin ligase complex, and plays essential roles in regulating different pathological and physiological processes. In this study, we attempted to explore the effects of FBW7 on SCI progression by the in vivo and in vitro experiments. SCI mice showed significantly reduced expression of FBW7 in spinal cord tissues. Promoting FBW7 expression via intrathecal injection of AAV9/FBW7 effectively improved locomotor function in SCI mice. Neuronal death in spinal cords of SCI mice was obviously ameliorated by FBW7 over-expression, along with greatly decreased expression of cleaved Caspase-3. In addition, microglial activation in spinal cord specimens was detected in SCI mice through increasing Iba-1 expression levels, which was, however, attenuated in SCI mice injected with AAV9/FBW7. Additionally, FBW7 over-expression dramatically restrained inflammatory response in spinal cord tissues of SCI mice, as evidenced by the down-regulated expression of tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) through blocking the activation of nuclear factor-κB (NF-κB) signaling. These anti-inflammatory effects of FBW7 were confirmed in LPS-stimulated mouse microglial BV2 cells. Finally, our in vitro studies showed that conditional medium (CM) collected from LPS-incubated BV2 cells markedly induced apoptosis in the isolated primary spinal neurons; However, this effect was overtly ameliorated by CM from LPS-exposed BV2 cells over-expressing FBW7. Thus, FBW7-regulated inflammation in microglial cells was involved in the amelioration of neuronal apoptosis during SCI development. Collectively, these findings illustrated that FBW7 expression was down-regulated in spinal cords of SCI mice, and promoting its expression could effectively mitigate SCI progression by repressing microglial inflammation and neuronal death.

Phytochemicals: Potential Therapeutic Interventions Against Coronavirus-Associated Lung Injury

Since the outbreak of coronavirus disease 2019 (COVID-19) in December 2019, millions of people have been infected and died worldwide. However, no drug has been approved for the treatment of this disease and its complications, which urges the need for finding novel therapeutic agents to combat. Among the complications due to COVID-19, lung injury has attained special attention. Besides, phytochemicals have shown prominent anti-inflammatory effects and thus possess significant effects in reducing lung injury caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Also, the prevailing evidence reveales the antiviral effects of those phytochemicals, including anti-SARS-CoV activity, which could pave the road in providing suitable lead compounds in the treatment of COVID-19. In the present study, candidate phytochemicals and related mechanisms of action have been shown in the treatment/protection of lung injuries induced by various methods. In terms of pharmacological mechanism, phytochemicals have shown potential inhibitory effects on inflammatory and oxidative pathways/mediators, involved in the pathogenesis of lung injury during COVID-19 infection. Also, a brief overview of phytochemicals with anti-SARS-CoV-2 compounds has been presented.

Dexmedetomidine alleviates LPS‑induced acute lung injury via regulation of the p38/HO‑1 pathway

Acute lung injury (ALI) is a common critical illness in clinical anesthesia and the intensive care unit that can cause acute hypoxic respiratory insufficiency. Despite various therapeutic regimes having been investigated, there is currently no effective pharmacotherapy available to treat ALI. Previous studies have reported that the NOD-like receptor protein 3 (NLRP3) signaling pathway plays an important role in the inflammatory response and is involved in the pathogenesis of ALI. Moreover, dexmedetomidine (Dex), an α2-adrenergic receptor activating agent, has been routinely used as an adjuvant therapy in treating inflammatory diseases, including ALI. However, the precise pathological mechanisms of Dex in ALI remain to be elucidated. Thus, the present study aimed to investigate the effects of the p38/heme oxygenase 1 (HO-1) signaling pathways in the pathological mechanisms of Dex in ALI. Newborn male Sprague-Dawley rats (n=48) were randomly divided into four groups (n=12 each), and an intravenous injection of lipopolysaccharide (LPS) was used to successfully induce the ALI model, with increased pulmonary damage, cell apoptosis, interleukin-1β (IL-1β) secretion and edema fluid in lungs. Moreover, the mRNA and protein expression levels of NLRP3 were significantly upregulated, while that of HO-1 were downregulated by LPS treatment. Furthermore, the levels of phosphorylated p38 were also upregulated in ALI rats. It was demonstrated that Dex administration significantly alleviated LPS-induced ALI, downregulated the secretion of IL-1β, decreased the expression of NLRP3, inhibited the phospho-activation of p38 and increased HO-1 expression. In addition, pharmacological inhibition of p38 using the inhibitor SB20380 further enhanced the effect of Dex. Collectively, these preliminarily results identified the effects of Dex intervention on the pathogenesis of ALI via the regulation of p38/HO-1 signaling pathways, which impacted the inflammatory effects, thus providing a theoretical basis and novel evidence for the development of new targets for clinical treatment of ALI.

Resveratrol protects human bronchial epithelial cells against nickel-induced toxicity via suppressing p38 MAPK, NF-κB signaling, and NLRP3 inflammasome activation

Nickel is a common environmental pollutant that can impair the lung, but the underlying mechanisms have not yet been fully elucidated. Furthermore, natural products are generally used to inhibit cell damage induced by heavy metal. Resveratrol possesses wide biological activities, including anti-inflammation and antioxidative stress. This study was conducted to explore the toxicity of nickel on human bronchial epithelial (BEAS-2B) cells and evaluate the protective effect of resveratrol. The results showed that nickel could induce cell apoptosis, increase oxidative stress, and promote the expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, C-reaction protein. Western blot analysis showed that nickel activated p38 mitogen-activated protein kinase (MAPK), nuclear factor-kappa B, and nucleotide-binding oligomerization domain-like receptor pyrin-domain-containing protein 3 pathways, while resveratrol could reverse these effects. Our results suggested that resveratrol could protect BEAS-2B cells from nickel-induced cytotoxicity. Therefore, resveratrol is a potential chemopreventive agent against nickel-induced lung disease.

Coumarins as Modulators of the Keap1/Nrf2/ARE Signaling Pathway

The Keap1/Nrf2/ARE system is a central defensive mechanism against oxidative stress which plays a key role in the pathogenesis and progression of many diseases. Nrf2 is a redox-sensitive transcription factor controlling a variety of downstream antioxidant and cytodefensive genes. Nrf2 has a powerful anti-inflammatory activity mediated via modulating NF-κB. Therefore, pharmacological activation of Nrf2 is a promising therapeutic strategy for the treatment/prevention of several diseases that are underlined by both oxidative stress and inflammation. Coumarins are natural products with promising pharmacological activities, including antioxidant, anticancer, antimicrobial, and anti-inflammatory efficacies. Coumarins are found in many plants, fungi, and bacteria and have been widely used as complementary and alternative medicines. Some coumarins have shown an ability to activate Nrf2 signaling in different cells and animal models. The present review compiles the research findings of seventeen coumarin derivatives of plant origin (imperatorin, visnagin, urolithin B, urolithin A, scopoletin, esculin, esculetin, umbelliferone, fraxetin, fraxin, daphnetin, anomalin, wedelolactone, glycycoumarin, osthole, hydrangenol, and isoimperatorin) as antioxidant and anti-inflammatory agents, emphasizing the role of Nrf2 activation in their pharmacological activities. Additionally, molecular docking simulations were utilized to investigate the potential binding mode of these coumarins with Keap1 as a strategy to disrupt Keap1/Nrf2 protein-protein interaction and activate Nrf2 signaling.

Spiraea prunifolia var. simpliciflora Attenuates Oxidative Stress and Inflammatory Responses in a Murine Model of Lipopolysaccharide-Induced Acute Lung Injury and TNF-α-Stimulated NCI-H292 Cells

Spiraea prunifolia var. simpliciflora (SP) is traditionally used as an herbal remedy to treat fever, malaria, and emesis. This study aimed to evaluate the anti-oxidative and anti-inflammatory properties of the methanol extract of SP leaves in tumor necrosis factor (TNF)-α-stimulated NCI-H292 cells and in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. SP decreased the number of inflammatory cells and the levels of TNF-α, interleukin (IL)-1β, and IL-6 in the bronchoalveolar lavage fluid, and inflammatory cell infiltration in the lung tissues of SP-treated mice. In addition, SP significantly suppressed the mRNA and protein levels of TNF-α, IL-1β, and IL-6 in TNF-α-stimulated NCI-H292 cells. SP significantly suppressed the phosphorylation of the mitogen-activated protein kinases (MAPKs) and p65-nuclear factor-kappa B (NF-κB) in LPS-induced ALI mice and TNF-α-stimulated NCI-H292 cells. SP treatment enhanced the nuclear translocation of nuclear factor erythroid 2-related factor (Nrf2) with upregulated antioxidant enzymes and suppressed reactive oxygen species (ROS)-mediated oxidative stress in the lung tissues of LPS-induced ALI model and TNF-α-stimulated NCI-H292 cells. Collectively, SP effectively inhibited airway inflammation and ROS-mediated oxidative stress, which was closely related to its ability to induce activation of Nrf2 and inhibit the phosphorylation of MAPKs and NF-κB. These findings suggest that SP has therapeutic potential for the treatment of ALI.

Advances in research into the mechanisms of Chinese Materia Medica against acute lung injury

Acute lung injury (ALI) is a common and serious disease. Numerous treatment options are available but they do not improve quality of life or reduce mortality for ALI patients. Here, we review the treatments for ALI to provide basic data for ALI drug therapy research and development. Chinese Materia Medica (CMM) has long been the traditional clinical approach in China for the treatment of ALI and it has proven efficacy. The continued study of CMM has disclosed new potential therapeutic ingredients for ALI. However, few reviews summarize the currently available CMM-based anti-ALI drugs. Therefore, the systematic analysis of research progress in anti-ALI CMM is of great academic and clinical value. The aim of the present review is to describe CMM-based research progress in ALI treatment. Data were compiled by electronic retrieval (CNKI, SciFinder, PubMeds, Google Scholar, Web of Science) and from articles, patents and ethnopharmacological literature in university libraries were systematically studied. This review introduces progress in research on the etiology and mechanisms of ALI, the anti-ALI theory and modes of action in traditional Chinese medicine (TCM), anti-ALI active constituents of CMM, research progress in experimental methods of CMM anti-ALI, the anti-ALI molecular mechanisms of CMM, the anti-ALI efficacy of CMM formulae, and the potential toxicity of CMM and the antidotes for it. Scholars have investigated the anti-ALI molecular mechanism of CMM from various direction and have made substantial progress. This research explored the above aspects, enriched the anti-ALI theory of CMM and established the clinical significance and developmental prospects of ALI treatment by CMM. Because of the high frequency of drugs such as glucocorticoids or antibiotics, Western medicine lacks the advantages of CMM in terms of overall anti-ALI efficacy. In the future, the development of CMM-based anti-ALI therapies will become a major trend in the field of ALI drug development. Successful clinical safety and efficacy validations will promote and encourage the use of CMM. It provides fundamental theoretical support for the discovery and use of CMM resources through the comprehensive analysis of various anti-ALI CMM report databases.

Preventive effects of fraxin on ischemia/reperfusion-induced acute kidney injury in rats

AIM

Kidney ischemia reperfusion (IR) injury is an important health problem resulting in acute kidney failure. The oxidative stress and inflammatory process are the underlying mechanisms of IR injury. It has been purposed in this study to research the possible protective effects of fraxin on kidney injury induced by IR.

MATERIAL AND METHODS

32 Sprague Dawley male rats were divided into 4 groups. The groups were organized as follows; sham, IR, IR + fraxin 10 mg/kg, and IR + 50 mg/kg fraxin groups. Some oxidant, antioxidant and inflammatory parameters were evaluated in kidney tissues removed at the end of our experimental study.

KEY FINDINGS

It was detected that the oxidant and proinflammatory markers increased and antioxidant parameters decreased in IR group but the results significantly reversed in treatment groups compared to IR group. And also, 8-OHdG, NF-κB, HAVCR1 immunopositivities were at severe levels and these results attenuated in IR fraxin + 10 mg/kg, and IR + fraxin 50 mg/kg groups.

SIGNIFICANCE

These presented results have shown that fraxin performed protective effects against kidney injury induced by IR.

Fraxin inhibits lipopolysaccharide-induced inflammatory cytokines and protects against endotoxic shock in mice

Fraxin, the effective component isolated from Cortex Fraxini, has been reported to have anti-inflammation effects. The aim of this study was to explore the effect of fraxin on lipopolysaccharide (LPS)-induced endotoxic shock in mice. We used Kunming male mice to establish the model, and we found that fraxin could improve the survival rate of the LPS-induced mice. Histopathological study showed that fraxin could mitigate the injuries in LPS-induced lung and liver tissues. The levels of tumour necrosis factor-α and interleukin-6 both in serum and lung, liver tissues, and the productions of nitric oxide (NO), aspartate transaminase and alanine transaminase in serum were decreased by fraxin. Western blot assay demonstrated that the pretreatment with fraxin could downregulate LPS-induced protein expressions of nuclear factor-kappa B (NF-κB) and NLRP3 inflammatory corpuscle signalling pathways. Overall, fraxin had protective effects on LPS-induced endotoxic shock mice and the possible mechanisms might activate through NF-κB and NLRP3 inflammatory corpuscle signalling pathways.

The Defensive Action of LYRM03 on LPS-Induced Acute Lung Injury by NF-κB/TLR4/NLRP3 Signals

The aim of the current investigation was to study the role of 3-amino-2-hydroxy-4-phenyl-valyl-isoleucine (LYRM03) in lipopolysaccharide (LPS)-induced acute lung injury (ALI) and investigate its potential pathogenesis. An LPS-induced ALI model was produced with LPS (5 mg/kg) followed by 24 h of injury. Rats were randomly assigned to 6 groups for in vivo experiments: (1) Sham, (2) LYRM03 (20 mg/kg), (3) LPS, (4) LPS plus LYRM03 (5 mg/kg), (5) LPS plus LYRM03 (10 mg/kg), and (6) LPS plus LYRM03 (20 mg/kg). The rat alveolar macrophage cell line (NR8383) cells were divided into 6 groups for in vitro experiments: (1) Sham, (2) LYRM03 (200 μmol/L), (3) LPS (100 ng/mL), (4) LPS plus LYRM03 (50 μmol/L), (5) LPS plus LYRM03 (100 μmol/L), and (6) LPS plus LYRM03 (200 μmol/L). Further study about siRNA targeting NF-κB p65, TLR4, and NLRP3 to explore the potential mechanism of LYRM03 in the LPS-induced ALI models have been done. Therefore, LYRM03 decreased LPS-induced ALI and NR8383 activation as demonstrated through hematoxylin-eosin staining and western blot analysis in vivo and in vitro. LYRM03 ameliorated the content of protein in bronchoalveolar lavage fluid, myeloperoxidase in the lung and malondialdehyde (MDA) in serum. In addition, LYRM03 ameliorated the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-18 (IL-18) in the serum of rats and the supernatant of NR8383 cells. Moreover, LYRM03 significantly inhibited the activities of nuclear factor kappa B (NF-κB), myeloid differentiation factor 88 (MyD88), and toll-like receptor 4 (TLR4). LYRM03 also reduced the increase in the inflammasome, including apoptosis-related speck-like protein containing CARD (ASC), and NOD-like receptor 3 (NLRP3), in LPS-stimulated rats and NR8383 cells. The extent of injury and lung injury scores in the LYRM03 (20 mg/kg) + siRNA targeting NF-κB p65, TLR4, or NLRP3 + LPS-treated rats were higher than that in the LYRM03 (20 mg/kg) + LPS-treated rats. In summary, LYRM03 conferred an intensely lung defensive action on LPS-induced ALI in vivo and in vitro, which could be associated with the abatement of TLR4-induced NLRP3/NF-κB.

Phosphodiesterase-4 Inhibitor Roflumilast Attenuates Pulmonary Air Emboli-Induced Lung Injury

BACKGROUND

Pulmonary air embolism (PAE)-induced acute lung injury (ALI) can be caused by massive air entry into the lung circulation. PAE can occur during diving, aviation, and some iatrogenic invasive procedures. PAE-induced ALI presents with severe inflammation, hypoxia, and pulmonary hypertension, and it is a serious complication resulting in significant morbidity and mortality. Phosphodiesterase-4 (PDE4) inhibitors can regulate inflammation and are therefore expected to have a therapeutic effect on ALI. However, the effect of the PDE4 inhibitor roflumilast on PAE-induced ALI is unknown.

METHODS

The PAE model was undertaken in isolated-perfused rat lungs. Four groups (n = 6 in each group) were defined as follows: control, PAE, PAE + roflumilast 2.5 mg/kg, and PAE + roflumilast 5 mg/kg. Induction of PAE-induced ALI was achieved via the infusion of 0.7 cc air through the pulmonary artery. Roflumilast was administered via perfusate. All groups were assessed for pulmonary microvascular permeability, lung histopathology changes, pulmonary edema (lung weight/body weight, lung wet/dry weight ratio), tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-17, nuclear factor-kappa B (NF-κB), and inhibitor of NF-κB alpha (IκB-α).

RESULTS

After the induction of air, PAE-induced ALI presented with pulmonary edema, pulmonary microvascular hyperpermeability, and lung inflammation with neutrophilic sequestration. The PAE-induced ALI also presented with increased expressions of IL-1β, IL-6, IL-8, IL-17, TNF-α, and NF-κB and decreased expression of IκB-α. The administration of roflumilast decreased pulmonary edema, inflammation, cytokines, NF-κB, and restored IκB-α level.

CONCLUSIONS

PAE-induced ALI presents with lung inflammation with neutrophilic sequestration, pulmonary edema, hyperpermeability, increased cytokine levels, and activation of the NF-κB pathway. Roflumilast attenuates lung edema and inflammation and downregulates the NF-κB pathway and cytokines.

Carbenoxolone ameliorates insulin sensitivity in obese mice induced by high fat diet via regulating the IκB-α/NF-κB pathway and NLRP3 inflammasome

The characteristic feature of obesity and insulin resistance is chronic low-grade inflammation. Nod-Like Receptor Pyrin 3 (NLRP3) inflammasome plays a central role in obesity-induced insulin resistance. However, how does Carbenoxolone (CBX) play its role in ameliorating insulin resistance in peripheral tissues of obese mice induced by high-fat diet (HFD) remains unknown. In our study, we explored the molecular mechanism of CBX in improving insulin resistance in liver and skeletal muscle in mice induced by the HFD. Our results revealed that in the CBX group, a significant decrease in fasting blood glucose, insulin and HOMA-IR score were observed. CBX could attenuate intracellular lipid accumulation and inflammation aggravation in liver and skeletal muscle. Besides, treatment with CBX could significantly reduce expressions of p-IκB-α, p-NF-κB, p-IRS-1, NLRP3 and inflammatory factors, increase expressions of p-PI3K and p-AKT. Therefore, CBX could dramatically improve insulin resistance in liver and skeletal muscle in mice induced by the high-fat diet. In conclusions, we demonstrate that CBX has a significant protective effect on diet-induced obesity in mice. The potential mechanisms include inhibiting IκB-α/NF-κB pathway, restricting the production of NLRP3 inflammasome and other inflammatory factors, reducing the expression of p-IRS-1, increasing the expressions of p-PI3K and p-AKT, thus ameliorating insulin resistance in liver and skeletal muscle of high-fat diet mice. Therefore CBX is an active agent against diet-induced obesity and is given the opportunity for the treatment of obesity related diseases.