Ferulic acid alleviates lipopolysaccharide-induced acute lung injury through inhibiting TLR4/NF-κB signaling pathway

Opuntia ficus-indica cladodes extract inhibits human neutrophil pro-inflammatory functions and protects rats from acetic acid-induced ulcerative colitis

The increased production of reactive oxygen species (ROS) by human neutrophils can lead to oxidative imbalances and several diseases, such as inflammatory bowel disease (IBD). Opuntia ficus-indica (O. ficus-indica) is rich in bioactive substances with anti-inflammatory properties. This study aimed to identify the bioactive compounds present in aqueous cladodes extract (ACE) of O. ficus-indica using high-performance liquid chromatography (HPLC) and to test its effects on human neutrophil inflammatory functions and on ulcerative colitis (UC) induced by acetic acid (Aa) in rats. ROS production and degranulation by neutrophils were assessed by luminol-amplified chemiluminescence, enzymatic techniques, and western blotting. In vivo, the experiment involved seven groups of rats: a negative control group (NaCl), the acetic acid group (Aa), and groups treated with oral sulfasalazine (150 mg/kg) or various doses of ACE for 7 days. Colonic lesions were induced by an intra-rectal Aa injection, and inflammation was assessed. HPLC analysis identified gallic acid, catechin, caffeic acid, and ferulic acid as major compounds in ACE. In vitro, ACE inhibited neutrophil ROS production, including superoxide anion produced by NADPH oxidase, and significantly reduced myeloperoxidase activity and neutrophil degranulation. In vivo, ACE protected rats from Aa-induced histopathological damage of the colonic mucosa, significantly increased catalase, superoxide dismutase and reduced glutathione levels, and significantly suppressed the increases of plasma cytokines (TNF-α and IL-1β) observed in the Aa group. In conclusion, O. ficus-indica ACE has significant anti-inflammatory properties by restoring oxidative balance, indicating that it could be a potential source of therapeutic agents for inflammatory diseases, particularly UC.

Network pharmacology-based research into the mechanism of ferulic acid on acute lung injury through enhancing transepithelial sodium transport

ETHNOPHARMACOLOGICAL RELEVANCE

Ferulic acid (FA) has shown potential therapeutic applications in treating lung diseases. However, the underlying mechanisms by which FA ameliorates acute lung injury (ALI) have not been distinctly elucidated.

AIM OF THE STUDY

The project aims to observe the therapeutic effects of FA on lipopolysaccharide-induced ALI and to elucidate its specific mechanisms in regulating epithelial sodium channel (ENaC), which majors in alveolar fluid clearance during ALI.

MATERIALS AND METHODS

In this study, the possible pathways of FA were determined through network pharmacology analyses. The mechanisms of FA in ALI were verified by in vivo mouse model and in vitro studies, including primary alveolar epithelial type 2 cells and three-dimensional alveolar organoid models.

RESULTS

FA ameliorated ALI by improving lung pathological changes, reducing pulmonary edema, and upregulating the α/γ-ENaC expression in C57BL/J male mice. Simultaneously, FA was observed to augment ENaC levels in both three-dimensional alveolar organoid and alveolar epithelial type 2 cells models. Network pharmacology techniques and experimental data from inhibition or knockdown of IkappaB kinase β (IKKβ) proved that FA reduced the phosphorylation of IKKβ/nuclear factor-kappaB (NF-κB) and eliminated the lipopolysaccharide-inhibited expression of ENaC, which could be regulated by nuclear protein NF-κB p65 directly.

CONCLUSIONS

FA could enhance the expression of ENaC at least in part by inhibiting the IKKβ/NF-κB signaling pathway, which may potentially pave the way for promising treatment of ALI.

Ferulic Acid: A Comprehensive Review

Ferulic acid (FA), a phenolic compound abundant in the cell walls of seeds, leaves, and roots of various fruits, vegetables, cereals, and grains, is renowned for its wide range of biological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. Despite its therapeutic potential, the clinical application of FA is hindered by challenges such as poor water solubility, limited bioavailability, rapid metabolism, and instability under physiological conditions. To address these issues, nanotechnology has emerged as a transformative approach, enhancing FA's pharmacokinetic profile. Various nanoparticle-based systems, including polymer-based and lipid-based nanoparticles, have been developed to encapsulate FA. These systems have demonstrated significant improvements in FA's solubility, stability, and bioavailability, with studies showing enhanced antioxidant activity and controlled release profiles. Further, the surface engineering of these nanoparticles provides targeted drug/phytochemical delivery potential. The targeted delivery of drugs/phytochemicals significantly enhances the therapeutic efficacy and minimizes systemic side effects. This review explores the therapeutic potential of FA, the limitations in its clinical application, and the advancements in nanoparticle-based delivery systems that are paving the way for its effective therapeutic use.

Targeting ferroptosis using Chinese herbal compounds to treat respiratory diseases

BACKGROUND

Respiratory diseases pose a grave threat to human life. Therefore, understanding their pathogenesis and therapeutic strategy is important. Ferroptosis is a novel type of iron-dependent programmed cell death, distinct from apoptosis, necroptosis, and autophagy, characterised by iron, reactive oxygen species, and lipid peroxide accumulation, as well as glutathione (GSH) depletion and GSH peroxidase 4 (GPX4) inactivation. A close association between ferroptosis and the onset and progression of respiratory diseases, including chronic obstructive pulmonary disease, acute lung injury, bronchial asthma, pulmonary fibrosis, and lung cancer, has been reported. Recent studies have shown that traditional Chinese medicine (TCM) compounds exhibit unique advantages in the treatment of respiratory diseases owing to their natural properties and potential efficacy. These compounds can effectively regulate ferroptosis by modulating several key signalling pathways such as system Xc- -GSH-GPX4, NCOA4-mediated ferritinophagy, Nrf2-GPX4, and Nrf2/HO-1, thus playing a positive role in improving respiratory diseases.

PURPOSE

This comprehensive review systematically outlines the regulatory role of ferroptosis in the onset and progression of respiratory diseases and provides evidence for treating respiratory diseases by targeting ferroptosis with TCM compounds. These insights aim to offer potential remedies for the clinical prevention and treatment of respiratory diseases.

STUDY DESIGN AND METHODS

We searched scientific databases PubMed, Web of Science, Scopus, and CNKI using keywords such as "ferroptosis","respiratory diseases","chronic obstructive pulmonary disease","bronchial asthma","acute lung injury","pulmonary fibrosis","lung cancer","traditional Chinese medicine","traditional Chinese medicine compound","monomer", and "natural product" to retrieve studies on the therapeutic potential of TCM compounds in ameliorating respiratory diseases by targeting ferroptosis. The retrieved data followed PRISMA criteria (preferred reporting items for systematic review).

RESULTS

TCM compounds possess unique advantages in treating respiratory diseases, stemming from their natural origins and proven clinical effectiveness. TCM compounds can exert therapeutic effects on respiratory diseases by regulating ferroptosis, which mainly involves modulation of pathways such as system Xc- -GSH-GPX4,NCOA4-mediated ferritinophagy, Nrf2-GPX4, and Nrf2/HO-1.

CONCLUSION

TCM compounds have demonstrated promising potential in improving respiratory diseases through the regulation of ferroptosis. The identification of specific TCM-related inducers and inhibitors of ferroptosis holds great significance in developing more effective strategies. However, current research remains confined to animal and cellular studies, emphasizing the imperative for further verifications through high-quality clinical data.

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.

Synthesis and Anti-Inflammatory Activity of Ferulic Acid-Sesquiterpene Lactone Hybrids

Acute lung injury (ALI) is a respiratory failure disease associated with high mortality rates in patients. The primary pathological damage is attributed to the excessive release of pro-inflammatory mediators in pulmonary tissue. However, specific therapy for ALI has not been developed. In this study, a series of novel ferulic acid-parthenolide (FA-PTL) and ferulic acid-micheliolide (FA-MCL) hybrid derivatives were designed, synthesized, and evaluated for their anti-inflammatory activities in vitro. Compounds 2, 4, and 6 showed pronounced anti-inflammatory activity against LPS-induced expression of pro-inflammatory cytokines in vitro. Importantly, compound 6 displayed good water solubility, and treatment of mice with compound 6 (10 mg/kg) significantly prevented weight loss and ameliorated inflammatory cell infiltration and edema in lung tissue, as well as improving the alveolar structure. These results suggest that compound 6 (((1aR,7aS,8R,10aS,10bS,E)-8-((dimethylamino)methyl)-1a-methyl-9-oxo-1a,2,3,6,7,7a,8,9,10a,10b-decahydrooxireno[2',3':9,10]cyclodeca[1,2-b]furan-5-yl)methyl (E)-3-(4-hydroxy-3-methoxyphenyl)acrylate 2-hydroxypropane-1,2,3-tricarboxylate) might be considered as a lead compound for further evaluation as a potential anti-ALI agent.

Insampaedok-San Extract Exerts an Immune-Enhancing Effect through NF-κB p65 Pathway Activation

Insampaedok-san (IS) has traditionally been prescribed as a medication for cold-related symptoms in Northeast Asia, including Korea and China. In this study, we focused on elucidating the molecular mechanism underlying the immunomodulatory activity of IS water extract (ISE) in macrophages. ISE significantly enhanced the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) by increasing the expression of inducible NO synthase and cyclooxygenase-2 (COX-2) in a dose-dependent manner. ISE, which consists of many herbs, contains a large number of active compounds whose pharmacological targets and mechanisms are complicated. Therefore, network pharmacology analysis was used to predict the potential key components, targets, and mechanisms of ISE as immunomodulators. Subsequently, the network pharmacology results were validated experimentally. Seven key components were identified through HPLC-QTOF-MS. As predicted by the network pharmacology analysis, ISE increased the mRNA expression of Tnf and Il6. Furthermore, ISE increased the phosphorylation, nuclear translocation, and transcriptional activity of the p65 subunit of the nuclear factor-κB (NF-κB) signaling pathway. In contrast, rapamycin, an NF-κB inhibitor, suppressed the ISE-induced mRNA expression of Tnf and Il6. In conclusion, ISE is an immune activator that can elevate the production of NO, PGE2, and proinflammatory cytokines mediated by NF-κB signaling.

Druggable targets for the immunopathy of Alzheimer's disease

Alzheimer's disease (AD) is one of the leading threats to the health and socioeconomic well-being of humankind. Though research to develop disease modifying therapies for AD has traditionally focussed on the misfolding and aggregation of proteins, this approach has failed to yield a definitively curative agent. Accordingly, the search for additional or alternative approaches is a medicinal chemistry priority. Dysfunction of the brain's neuroimmune-neuroinflammation axis has emerged as a leading contender. Neuroimmunity however is mechanistically complex, rendering the recognition of candidate receptors a challenging task. Herein, a review of the role of neuroimmunity in the biomolecular pathogenesis of AD is presented with the identification of a 'druggable dozen' targets; in turn, each identified target represents one or more discrete receptors centred on a common biochemical mechanism. The druggable dozen is composed of both cellular and molecular messenger targets, with a 'targetable ten' microglial targets as well as two cytokine-based targets. For each target, the underlying molecular basis, with a consideration of strengths and weaknesses, is considered.

Molecular mechanism of ferulic acid and its derivatives in tumor progression

Cancer is a significant disease that poses a major threat to human health. The main therapeutic methods for cancer include traditional surgery, radiotherapy, chemotherapy, and new therapeutic methods such as targeted therapy and immunotherapy, which have been developed rapidly in recent years. Recently, the tumor antitumor effects of the active ingredients of natural plants have attracted extensive attention. Ferulic acid (FA), (3-methoxy-4-hydroxyl cinnamic), with the molecular formula is C₁₀H₁₀O₄, is a phenolic organic compound found in ferulic, angelica, jujube kernel, and other Chinese medicinal plants but is also, abundant in rice bran, wheat bran, and other food raw materials. FA has anti-inflammatory, analgesic, anti-radiation, and immune-enhancing effects and also shows anticancer activity, as it can inhibit the occurrence and development of various malignant tumors, such as liver cancer, lung cancer, colon cancer, and breast cancer. FA can cause mitochondrial apoptosis by inducing the generation of intracellular reactive oxygen species (ROS). FA can also interfere with the cell cycle of cancer cells, arrest most cancer cells in G₀/G₁ phase, and exert an antitumor effect by inducing autophagy; inhibiting cell migration, invasion, and angiogenesis; and synergistically improving the efficacy of chemotherapy drugs and reducing adverse reactions. FA acts on a series of intracellular and extracellular targets and is involved in the regulation of tumor cell signaling pathways, including the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT), B-cell lymphoma-2 (Bcl-2), and tumor protein 53 (P53) pathways and other signaling pathways. In addition, FA derivatives and nanoliposomes, as platforms for drug delivery, have an important regulatory effect on tumor resistance. This paper reviews the effects and mechanisms of antitumor therapies to provide new theoretical support and insight for clinical antitumor therapy.

Ferulic Acid: A Review of Pharmacology, Toxicology, and Therapeutic Effects on Pulmonary Diseases

Ferulic acid (FA), a prevalent dietary phytochemical, has many pharmacological effects, including anti-oxidation and anti-inflammation effects, and has been widely used in the pharmaceutical, food, and cosmetics industries. Many studies have shown that FA can significantly downregulate the expression of reactive oxygen species and activate nuclear factor erythroid-2-related factor-2/heme oxygenase-1 signaling, exerting anti-oxidative effects. The anti-inflammatory effect of FA is mainly related to the p38 mitogen-activated protein kinase and nuclear factor-kappaB signaling pathways. FA has demonstrated potential clinical applications in the treatment of pulmonary diseases. The transforming growth factor-β1/small mothers against decapentaplegic 3 signaling pathway can be blocked by FA, thereby alleviating pulmonary fibrosis. Moreover, in the context of asthma, the T helper cell 1/2 imbalance is restored by FA. Furthermore, FA ameliorates acute lung injury by inhibiting nuclear factor-kappaB and mitogen-activated protein kinase pathways via toll-like receptor 4, consequently decreasing the expression of downstream inflammatory mediators. Additionally, there is a moderate neuraminidase inhibitory activity showing a tendency to reduce the interleukin-8 level in response to influenza virus infections. Although the application of FA has broad prospects, more preclinical mechanism-based research should be carried out to test these applications in clinical settings. This review not only covers the literature on the pharmacological effects and mechanisms of FA, but also discusses the therapeutic role and toxicology of FA in several pulmonary diseases.

Effects of Herbs and Derived Natural Products on Lipopolysaccharide-Induced Toxicity: A Literature Review

Introduction

Oxidative stress (OS) during inflammation can increase inflammatory responses and damage tissue. Lipopolysaccharide (LPS) can induce oxidative stress and inflammation in several organs. Natural products have several biological activities including anti-inflammatory, antioxidant, and immunoregulatory properties. The aims of the study are to study the possible therapeutic effects of natural products on LPS inducing toxicity on the nervous system, lung, liver, and immune system.

Methods

The in vitro and in vivo research articles that were published in the last 5 years were included in the current study. The keywords included "lipopolysaccharide," "toxicity," "natural products," and "plant extract" were searched in different databases such as Scopus, PubMed, and Google Scholar until October 2021.

Results

The results of most studies indicated that some medicinal herbs and their potent natural products can help to prevent, treat, and manage LPS-induced toxicity. Medicinal herbs and plant-derived natural products showed promising effects on managing and treating oxidative stress, inflammation, and immunomodulation by several mechanisms.

Conclusion

However, these findings provide information about natural products for the prevention and treatment of LPS-induced toxicity, but the scientific validation of natural products requires more evidence on animal models to replace modern commercial medicine.

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.

rFGF4 alleviates lipopolysaccharide-induced acute lung injury by inhibiting the TLR4/NF-κB signaling pathway

Acute lung injury (ALI) is a serious and common clinical disease. Despite significant progress in ALI treatment, the morbidity and mortality rates remain high. However, no effective drug has been discovered for ALI. FGF4, a member of the FGF family, plays an important role in the regulation of various physiological and pathological processes. Therefore, in the present study, we aimed to study the protective effects of FGF4 against LPS-induced lung injury in vivo and in vitro. We found that rFGF4 treatment improved the lung W/D weight ratio, the survival rate, immune cell infiltration and protein concentrations in mice with LPS-induced ALI. Histological analysis revealed that rFGF4 significantly attenuated lung tissue injury and cell apoptosis. Furthermore, rFGF4 inhibited the activation of the TLR4/NF-κB signaling pathway and the production of pro-inflammatory mediators in LPS-injured lung tissues, murine alveolar macrophages (MH-S) and murine pulmonary epithelial (MLE-12) cells. The results of cell experiments further verified that rFGF4 inhibited the production of inflammatory mediators in MH-S cells and MLE-12 cells by regulating the TLR4/NF-κB signaling pathway. These results revealed that rFGF4 protected lung tissues and inhibited inflammatory mediators in mice with LPS-induced ALI by inhibiting the TLR4/NF-κB signaling pathway in MH-S and MLE-12 cells.

Protective Effects of Ferulic Acid on Metabolic Syndrome: A Comprehensive Review

Metabolic syndrome (MetS) is a complex disease in which protein, fat, carbohydrates and other substances are metabolized in a disorderly way. Ferulic acid (FA) is a phenolic acid found in many vegetables, fruits, cereals and Chinese herbs that has a strong effect on ameliorating MetS. However, no review has summarized the mechanisms of FA in treating MetS. This review collected articles related to the effects of FA on ameliorating the common symptoms of MetS, such as diabetes, hyperlipidemia, hypertension and obesity, from different sources involving Web of Science, PubMed and Google Scholar, etc. This review summarizes the potential mechanisms of FA in improving various metabolic disorders according to the collected articles. FA ameliorates diabetes via the inhibition of the expressions of PEPCK, G6Pase and GP, the upregulation of the expressions of GK and GS, and the activation of the PI3K/Akt/GLUT4 signaling pathway. The decrease of blood pressure is related to the endothelial function of the aortas and RAAS. The improvement of the lipid spectrum is mediated via the suppression of the HMG-Co A reductase, by promoting the ACSL1 expression and by the regulation of the factors associated with lipid metabolism. Furthermore, FA inhibits obesity by upregulating the MEK/ERK pathway, the MAPK pathway and the AMPK signaling pathway and by inhibiting SREBP-1 expression. This review can be helpful for the development of FA as an appreciable agent for MetS treatment.

Ferulic acid alleviates alveolar epithelial barrier dysfunction in sepsis-induced acute lung injury by activating the Nrf2/HO-1 pathway and inhibiting ferroptosis

CONTEXT

Ferulic acid (FA) has antioxidative and anti-inflammatory effects, and is a promising drug to treat sepsis.

OBJECTIVE

To study the therapeutic effect of FA in sepsis-induced acute lung injury (ALI) and its underlying mechanisms.

MATERIALS AND METHODS

The caecal ligation and puncture (CLP) manoeuvre was applied to establish a murine model of sepsis-induced ALI, and female BALB/c mice (6 mice per group) were subjected to 100 mg/kg FA or 0.8 mg/kg ferrostatin-1 (Fer-1, ferroptosis inhibitor) treatment to clarify the role of FA in preserving alveolar epithelial barrier function and inhibiting ferroptosis. Lipopolysaccharide (LPS; 500 ng/mL)-induced cell models were prepared and subjected to FA (0.1 μM), sh-Nrf2, and Fe (Fe-citrate, ferroptosis inducer; 5 M) treatment to study the in vitro effect of FA on LPS-induced alveolar epithelial cell injury and the role of the Nrf2/HO-1 pathway.

RESULTS

We found that FA decreased the lung injury score (48% reduction), lung wet/dry weight ratio (33% reduction), and myeloperoxidase activity (58% reduction) in sepsis-induced ALI. Moreover, FA inhibited ferroptosis of alveolar epithelial cells and improved alveolar epithelial barrier dysfunction. The protective role of FA against alveolar epithelial barrier dysfunction could be reversed by the ferroptosis inducer Fe-citrate, suggesting that FA alleviates alveolar epithelial barrier dysfunction by inhibiting ferroptosis. Mechanistically, we found that FA inhibited ferroptosis of alveolar epithelial cells by activating the Nrf2/HO-1 pathway.

CONCLUSION

Collectively, our data highlighted the alleviatory role of ferulic acid in sepsis-induced ALI by activating the Nrf2/HO-1 pathway and inhibiting ferroptosis, offering a new basis for sepsis treatment.

Ferulic acid: An extraordinarily neuroprotective phenolic acid with anti-depressive properties

BACKGROUND

Depression, one of the most common mental illnesses and mood disorder syndromes, can seriously harm physical and mental health. As the pathophysiology of depression remains unclear, there is a need to find novel therapeutic agents. Ferulic acid (FA), a phenolic compound found in various Chinese herbal medicines, has anti-inflammatory and free radical scavenging properties as well as a wide range of therapeutic effects against depression.

PURPOSE

In this review, we appraised preclinical research to fully discuss the anti-depression capacity of FA and discussed FAs' holistic characteristics that can contribute to better management of depression.

STUDY DESIGN

We reviewed the results of in vitro and in vivo experiments using FA to treat depression and explored the possible antidepressant pharmacological mechanisms of FA for the clinical treatment of depression.

METHODS

Electronic databases, including PubMed, Google Scholar, and China National Knowledge Infrastructure, were searched from the beginning of the database creation to December 2021.

RESULTS

Studies on the antidepressant effects of FA show that it may exert such effects through various mechanisms. These include the following: the regulation of monoamine and non-monoamine neurotransmitter levels, inhibition of hypothalamic-pituitary-adrenal axis hyperfunction and neuroinflammation, promotion of hippocampal neurogenesis and upregulation brain-derived neurotrophic factor level, neuroprotection (inhibition of neuroinflammation, oxidative stress, mitochondrial dysfunction, and apoptosis), and downregulation of oxidative stress.

CONCLUSION

Preclinical studies on the antidepressant effects of FA were reviewed in this study, and research on the antidepressant mechanisms of FA was summarized, confirming that FA can exert antidepressant effects through various pharmacological mechanisms. However, more multicenter clinical case-control studies are needed to confirm the clinical efficacy of FA.

Salvianolactone acid A isolated from Salvia miltiorrhiza ameliorates lipopolysaccharide-induced acute lung injury in mice by regulating PPAR-γ

BACKGROUND

Severe inflammation of the lungs results from acute lung injury (ALI), a common life-threatening lung disease with a high mortality rate. The ligand-activated transcription factor peroxisome proliferator-activated receptor (PPAR) γ plays essential roles in diverse biological processes including inflammation, metabolism, development, and immune response. Salvianolactone acid A (SA) is a terpenoid derived from the herb Salvia miltiorrhiza. However, there is a scarcity of experimental evidence indicating whether the effect of SA on ALI occurs via PPAR-γ.

METHODS

SA (20 or 40 mg/kg, i.g., 1 time/day) was administered to mice for 3 d, followed by the induction of ALI by intranasal lipopolysaccharide (LPS, 10 mg/kg). The lung function and levels of inflammation, reactive oxygen species (ROS), immune cells, apoptosis, and PPAR-γ were examined. The antagonistic activity of GW9662 (GW, 1 µM, specific PPAR-γ blocker) and PPAR-γ transfection silencing against SA (10 μM) in BEAS-2B cells induced by LPS (10 μg/ml, 24 h) was also investigated to assess whether the observed effects caused by SA were mediated by PPAR-γ.

RESULTS

The results showed that lung histopathological injury, the B-line, the fluorescence intensity of live small animal, and the biomarkers in BALF or lung in the treatment of SA could regulate significantly. In addition, SA obviously decreased the levels of ROS and apoptosis in the primary lung cells, and MDA, increased the levels of GSH-Px and SOD. SA reduced levels of macrophages and neutrophils. Furthermore, SA reduced the protein levels of Keap-1, Cleaved-caspase-3, Cleaved-caspase-9, p-p65/p65, NLRP3, IL-1β, and upregulated the levels of p-Nrf2/Nrf2, HO-1, Bcl-2/Bax, PPAR-γ, p-AMPK/AMPK in lung tissue. In addition, silencing and inhibition of PPAR-γ effectively decreased the protective effects of SA in BEAS-2B cells induced by LPS, which might indicate that the active molecules of SA regulate ALI via mediation by PPAR-γ, which exhibited that the effect of SA related to PPAR-γ.

CONCLUSIONS

The anti-ALI effects of SA were partially mediated through PPAR-γ signaling. These data provide the molecular justification for the usage of SA in treating ALI and can assist in increasing the comprehensive utilization rate of Salvia miltiorrhiza.

Inhibition of KLF6 reduces the inflammation and apoptosis of type II alveolar epithelial cells in acute lung injury

BACKGROUND

The development of acute lung injury (ALI) into a severe stage leads to acute respiratory distress syndrome (ARDS). The morbidity and mortality of ALI and ARDS are very high. Objective: This study is aimed to explore the effect of Krüppel-like factor 6 (KLF6) on lipopolysaccharide (LPS)-induced type II alveolar epithelial cells in ALI by interacting with cysteine-rich angiogenic inducer 61 (CYR61).

MATERIAL AND METHODS

ALI mice model and LPS-induced type II alveolar epithelial cells were conducted to simulate ALI in vivo and in vitro. The messenger RNA (mRNA) and protein expression of KLF6 in lung tissues were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis. Pathological changes in lung tissues were observed by hematoxylin and eosin (H&E) staining. The viability and KLF6 expression of A549 cells treated with different concentrations of LPS were detected by cell counting kit-8 (CCK-8) assay, RT-qPCR, and Western blot analysis. After indicated treatment, the viability and apoptosis of A549 cells were analyzed by CCK-8 and TUNEL assays, and the inflammation factors of A549 cells were detected by Enzyme-linked-immunosorbent serologic assay, RT-qPCR, and Western blot analysis. The combination of KLF6 and CYR61 was determined by chromatin immunoprecipitation (ChIP)-PCR and dual-luciferase reporter assay.

RESULTS

KLF6 expression was increased in lung tissues of ALI mice and LPS-induced A549 cells. Interference with KLF6 improved the viability, reduced the inflammatory damage, and promoted the apoptosis of LPS-induced A549 cells. In addition, KLF6 could bind to CYR61. Interference with KLF6 could decrease CYR61 expression in LPS-induced A549 cells. LPS also enhanced the TLR4/MYD88 signaling pathway, which was reversed by KLF6 interference. The above phenomena in LPS-induced A549 cells transfected with Si-KLF6 could be reversed by overexpression of CYR61.

CONCLUSION

Inhibition of KLF6 promoted the viability and reduced the inflammation and apoptosis of LPS-induced A549 cells, which was reversed by CYR61.

Potential “Therapeutic” Effects of Tocotrienol-Rich Fraction (TRF) and Carotene “Against” Bleomycin-Induced Pulmonary Fibrosis in Rats via TGF-β/Smad, PI3K/Akt/mTOR and NF-κB Signaling Pathways

Background: Pulmonary fibrosis (PF) is a chronic, progressive, and, ultimately, terminal interstitial disease caused by a variety of factors, ranging from genetics, bacterial, and viral infections, to drugs and other influences. Varying degrees of PF and its rapid progress have been widely reported in post-COVID-19 patients and there is consequently an urgent need to develop an appropriate, cost-effective approach for the prevention and management of PF. Aim: The potential “therapeutic” effect of the tocotrienol-rich fraction (TRF) and carotene against bleomycin (BLM)-induced lung fibrosis was investigated in rats via the modulation of TGF-β/Smad, PI3K/Akt/mTOR, and NF-κB signaling pathways. Design/Methods: Lung fibrosis was induced in Sprague-Dawley rats by a single intratracheal BLM (5 mg/kg) injection. These rats were subsequently treated with TRF (50, 100, and 200 mg/kg body wt/day), carotene (10 mg/kg body wt/day), or a combination of TRF (200 mg/kg body wt/day) and carotene (10 mg/kg body wt/day) for 28 days by gavage administration. A group of normal rats was provided with saline as a substitute for BLM as the control. Lung function and biochemical, histopathological, and molecular alterations were studied in the lung tissues. Results: Both the TRF and carotene treatments were found to significantly restore the BLM-induced alterations in anti-inflammatory and antioxidant functions. The treatments appeared to show pneumoprotective effects through the upregulation of antioxidant status, downregulation of MMP-7 and inflammatory cytokine expressions, and reduction in collagen accumulation (hydroxyproline). We demonstrated that TRF and carotene ameliorate BLM-induced lung injuries through the inhibition of apoptosis, the induction of TGF-β1/Smad, PI3K/Akt/mTOR, and NF-κB signaling pathways. Furthermore, the increased expression levels were shown to be significantly and dose-dependently downregulated by TRF (50, 100, and 200 mg/kg body wt/day) treatment in high probability. The histopathological findings further confirmed that the TRF and carotene treatments had significantly attenuated the BLM-induced lung injury in rats. Conclusion: The results of this study clearly indicate the ability of TRF and carotene to restore the antioxidant system and to inhibit proinflammatory cytokines. These findings, thus, revealed the potential of TRF and carotene as preventive candidates for the treatment of PF in the future.

Phenols and terpenoids: natural products as inhibitors of NLRP3 inflammasome in cardiovascular diseases

Inflammatory infiltration has been implicated in the pathogenesis of cardiovascular diseases (CVDs). The NLRP3 inflammasome is involved in the development of several types of CVDs, including myocardial infarction, myocardial ischemia-reperfusion damage, heart failure, atrial fibrillation, and hypertension. Inhibiting the activity of NLRP3 inflammasome can inhibit the progress of CVDs. However, there is no NLRP3 inflammasome inhibitor in clinic, and it is very important to find a safe and effective NLRP3 inhibitor. Phenols and terpenoids are naturally natural products that have many anti-inflammatory effects in CVDs by modulating the NLRP3 inflammatory pathway. Thus, 20 natural products from phenols and terpenoids for the treatment of cardiovascular disease based on the inhibition of NLRP3 inflammasome were summarized and screened. Docking results showed salvianolic acid B and ellagic acid in phenols, and oridonin and triptolide in terpenoids had a better binding activity with NLRP3, which can provide theoretical support for finding novel NLRP3 inflammasome inhibitors or lead compounds in the future.

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.

Ferulic acid ameliorates lipopolysaccharide-induced tracheal injury via cGMP/PKGII signaling pathway

BACKGROUND

Tracheal injury is a common clinical condition that still lacks an effective therapy at present. Stimulation of epithelial sodium channel (ENaC) increases Na⁺ transport, which is a driving force to keep tracheal mucosa free edema fluid during tracheal injury. Ferulic acid (FA) has been proved to be effective in many respiratory diseases through exerting anti-oxidant, anti-inflammatory, and anti-thrombotic effects. However, these studies rarely involve the level of ion transport, especially ENaC.

METHODS

C57BL/J male mice were treated intraperitoneally with normal saline or FA (100 mg/kg) 12 h before, and 12 h after intratracheal administration of lipopolysaccharide (LPS, 5 mg/kg), respectively. The effects of FA on tracheal injury were not only assessed through HE staining, immunofluorescence assay, and protein/mRNA expressions of ENaC located on tracheas, but also evaluated by the function of ENaC in mouse tracheal epithelial cells (MTECs). Besides, to explore the detailed mechanism about FA involved in LPS-induced tracheal injury, the content of cyclic guanosine monophosphate (cGMP) was measured, and Rp-cGMP (cGMP inhibitor) or cGMP-dependent protein kinase II (PKGII)-siRNA (siPKGII) were applied in primary MTECs, respectively.

RESULTS

Histological examination results demonstrated that tracheal injury was obviously attenuated by pretreatment of FA. Meanwhile, FA could reverse LPS-induced reduction of both protein/mRNA expressions and ENaC activity. ELISA assay verified cGMP content was increased by FA, and administration of Rp-cGMP or transfection of siPKGII could reverse the FA up-regulated ENaC protein expression in MTECs.

CONCLUSIONS

Ferulic acid can attenuate LPS-induced tracheal injury through up-regulation of ENaC at least partially via the cGMP/PKGII pathway, which may provide a promising new direction for preventive and therapeutic strategy in tracheal injury.

Ethyl ferulate protects against lipopolysaccharide-induced acute lung injury by activating AMPK/Nrf2 signaling pathway

Ethyl ferulate (EF) is abundant in Rhizoma Chuanxiong and grains (e.g., rice and maize) and possesses antioxidative, antiapoptotic, antirheumatic, and anti-inflammatory properties. However, its effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) is still unknown. In the present study, we found that EF significantly alleviated LPS-induced pathological damage and neutrophil infiltration and inhibited the gene expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) in murine lung tissues. Moreover, EF reduced the gene expression of TNF-α, IL-1β, IL-6, and iNOS and decreased the production of NO in LPS-stimulated RAW264.7 cells and BMDMs. Mechanistic experiments revealed that EF prominently activated the AMPK/Nrf2 pathway and promoted Nrf2 nuclear translocation. AMPK inhibition (Compound C) and Nrf2 inhibition (ML385) abolished the beneficial effect of EF on the inflammatory response. Furthermore, the protective effect of EF on LPS-induced ALI was not observed in Nrf2 knockout mice. Taken together, the results of our study suggest that EF ameliorates LPS-induced ALI in an AMPK/Nrf2-dependent manner. These findings provide a foundation for developing EF as a new anti-inflammatory agent for LPS-induced ALI/ARDS therapy.

Recent Advances in Biological Activity, New Formulations and Prodrugs of Ferulic Acid

Trans-ferulic acid (FA) is a derivative of 4-hydroxycinnamic acid, which is found in many food products, fruits and beverages. It has scientifically proven antioxidant, anti-inflammatory and antibacterial properties. However, its low ability to permeate through biological barriers (e.g., the blood-brain barrier, BBB), its low bioavailability and its fast elimination from the gastrointestinal tract after oral administration limit its clinical use, e.g., for the treatment of neurodegenerative diseases, such as Alzheimer's disease. Therefore, new nanotechnological approaches are developed in order to regulate intracellular transport of ferulic acid. The objective of this review is to summarize the last decade's research on biological properties of ferulic acid and innovative ways of its delivery, supporting pharmacological therapy.

Effects of dexmedetomidine on the expression profile of tsRNAs in LPS-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is characterized by impaired alveolar function and excessive inflammation, which is commonly seen in clinical anesthesia and intensive care units. tRNA-derived small RNA (tsRNA) is a non-coding RNA that can be used as a potential disease diagnostic biomarker. The connection between ALI and tsRNA remains unknown. We aimed to explore the possible regulatory functions and mechanisms of tsRNAs in ALI treated with DEX.

METHODS

Firstly, we established the ALI model by LPS injection and explored the effect of dexmedetomidine (DEX) treatment on lung damage. Then, the lung tissues were obtained from the LPS and LPS + DEX group for small RNA sequencing.

RESULTS

We proved that DEX could ameliorate pulmonary injury, and decreased inflammation, pulmonary edema, and ferroptosis (MDA down-regulation and GPX4 up-regulation) in ALI. Furthermore, in the tsRNA expression profile, the top 10 down-regulated tsRNAs were tsRNA-1018, tsRNA-3045b, tsRNA-5021a, tsRNA-1020, tsRNA-5002b, tsRNA-3045b, tsRNA-1026, tsRNA-5004a, tsRNA-5005b and tsRNA-1009, and the top 10 up-regulated tsRNAs were tsRNA-3025b, tsRNA-3025a, tsRNA-5016b, tsRNA-3042b, tsRNA-3029b, tsRNA-3028b, tsRNA-5006a, tsRNA-3027b, tsRNA-3027a, and tsRNA-5009b. The enrichment analysis of GO terms and KEGG pathways pointed that target genes of DE-tsRNAs were mainly enriched in regulation of transcription-associated GO terms, NF-kappa B signaling pathway, MAPK signaling pathway, and PI3K-Akt signaling pathway. The RT-qPCR results of tsRNA-1020 and tsRNA-1018 were in accordance with small RNA sequencing data.

CONCLUSION

DEX affected the abnormal expression of tsRNAs in ALI. These aberrantly expressed tsRNAs and enriched physiological processes provide a scientific basis for the diagnosis and treatment of ALI.

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

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

Baicalin Magnesium Salt Attenuates Lipopolysaccharide-Induced Acute Lung Injury via Inhibiting of TLR4/NF-κB Signaling Pathway

Baicalin (BA) magnesium salt (BA-Mg) is a good water-soluble ingredient extracted from Scutellaria baicalensis Georgi, a commonly used traditional Chinese medicine. This study is aimed at investigating whether BA-Mg could exert a better protective effect on lipopolysaccharide- (LPS-) induced acute lung injury (ALI) in mice and illuminate the underlying mechanisms in vivo and in vitro. Mice were intraperitoneally administrated with equimolar BA-Mg, BA, and MgSO₄ before LPS inducing ALI. Lung tissues and bronchoalveolar lavage fluid were collected for lung wet/dry ratio, histological examinations, cell counts, and biochemical analyses at 48 h post-LPS exposure. Meanwhile, the protein expressions of TLR4/NF-κB signaling pathway and proinflammatory cytokines in lung tissues and lung bronchial epithelial cells (BEAS-2B) were detected. The results showed BA-Mg pronouncedly ameliorated LPS-induced inflammatory response and histopathological damages, elevated antioxidant enzyme activity (SOD), and downregulated myeloperoxidase (MPO) and malonaldehyde (MDA) levels through the inhibition of TLR4/NF-κB signaling pathway activation. Moreover, the effect of BA-Mg was significantly better than that of BA and MgSO₄ in ameliorating symptoms. Overall, BA-Mg can effectively relieve inflammatory response and oxidative stress triggered by LPS, indicating it may be a potential therapeutic candidate for treating ALI.