The protective effect of Trillin LPS-induced acute lung injury by the regulations of inflammation and oxidative state

Inhaled aerosolized algal polysaccharides: A novel and reliable strategy for treating pneumonia through inflammation and oxidative stress inhibition

Sepsis-associated acute lung injury (ALI) poses a significant threat, characterized by inflammation and oxidative damage. Effective drugs targeting these aspects with reliable drug delivery systems are vital for ALI management. This study aimed to evaluate the influence of algal polysaccharides (APs) with aerosolized drug delivery in ALI mice and clarify the underlying mechanism. To induce the sepsis-associated acute lung injury (ALI) model, mice were administered intraperitoneal injections of 10 mg/kg LPS for 48 h in vivo. ALI mice received APs via atomization to arrive at different sites within the lungs. Lung tissue samples and bronchoalveolar lavage fluid (BALF) were collected to access lung injury parameters. Concurrently, western blotting, H&E staining, and immunofluorescence (IF) were applied to investigate the specific impact of APs on ALI. The results showed that APs protect lung tissue against ALI by inhibiting inflammation and mitigating oxidative stress-induced damage. This study highlights promising avenues for ALI intervention using natural compounds with anti-inflammatory and antioxidant properties.

Echinatin attenuates acute lung injury and inflammatory responses via TAK1-MAPK/NF-κB and Keap1-Nrf2-HO-1 signaling pathways in macrophages

Echinatin is an active ingredient in licorice, a traditional Chinese medicine used in the treatment of inflammatory disorders. However, the protective effect and underlying mechanism of echinatin against acute lung injury (ALI) is still unclear. Herein, we aimed to explore echinatin-mediated anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated ALI and its molecular mechanisms in macrophages. In vitro, echinatin markedly decreased the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated murine MH-S alveolar macrophages and RAW264.7 macrophages by suppressing inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) expression. Furthermore, echinatin reduced LPS-induced mRNA expression and release of interleukin-1β (IL-1β) and IL-6 in RAW264.7 cells. Western blotting and CETSA showed that echinatin repressed LPS-induced activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways through targeting transforming growth factor-beta-activated kinase 1 (TAK1). Furthermore, echinatin directly interacted with Kelch-like ECH-associated protein 1 (Keap1) and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to enhance heme oxygenase-1 (HO-1) expression. In vivo, echinatin ameliorated LPS-induced lung inflammatory injury, and reduced production of IL-1β and IL-6. These findings demonstrated that echinatin exerted anti-inflammatory effects in vitro and in vivo, via blocking the TAK1-MAPK/NF-κB pathway and activating the Keap1-Nrf2-HO-1 pathway.

Dose-dependent multi-organ injury following lipopolysaccharide gas inhalation

Lipopolysaccharide (LPS) is widely used to establish various animal models, including models of acute lung injury, cardiomyocyte damage, and acute kidney injury. Currently, there is no consensus on the diagnosis and treatment of LPS-induced disease. We herein present a case series of four patients who developed dose-dependent multi-organ injury, including acute lung injury and acute kidney injury, after inhaling LPS gas in a sealed room. These patients exhibited varying degrees of multi-organ injury characterized by inflammatory cell infiltration and secretion of proinflammatory cytokines. One patient showed progressive symptoms even with active treatment, leading to mild pulmonary fibrosis. This study emphasizes the importance of early diagnosis and treatment of significant LPS exposure and suggests personalized treatment approaches for managing LPS poisoning.

Dioscorea nipponica Makino: A comprehensive review of its chemical composition and pharmacology on chronic kidney disease

Chronic kidney disease (CKD) is a widespread ailment that significantly impacts global health. It is characterized by high prevalence, poor prognosis, and substantial healthcare costs, making it a major public health concern. The current clinical treatments for CKD are not entirely satisfactory, leading to a high demand for alternative therapeutic options. Chinese herbal medicine, with its long history, diverse varieties, and proven efficacy, offers a promising avenue for exploration. One such Chinese herbal medicine, Dioscorea nipponica Makino (DNM), is frequently used to treat kidney diseases. In this review, we have compiled studies examining the mechanisms of action of DNM in the context of CKD, focusing on five primary areas: improvement of oxidative stress, inhibition of renal fibrosis, regulation of metabolism, reduction of inflammatory response, and regulation of autophagy.

A2BR facilitates the pathogenesis of H. pylori-associated GU by inducing oxidative stress through p38 MAPK phosphorylation

Gastric ulcers significantly impact the quality of life of patients, the pathogenesis of which is closely associated with Helicobacter pylori (HP) infection. Oxidative stress is involved in the pathological mechanism of gastric ulcers. Recently, adenosine A2B Receptor (A2BR) was reported to activate the p38MAPK pathway. However, the role of A2BR in gastric ulcers remains unknown. In the present study, the biological function of A2BR in HP-induced gastric ulcers was investigated to explore novel targets for gastric ulcers. GES-1 cells were infected with HP, followed by incubation with 10 μM BAY60-6583 (A2BR agonist) and 25 nM PSB1115 (A2BR antagonist). In HP-infected GES-1 cells, an increased apoptotic rate, enhanced migration ability, excessive release of reactive oxygen species (ROS), increased malondialdehyde (MDA) levels, and decreased superoxide dismutase (SOD) activity were observed, accompanied by the activation of p38MAPK signaling, which were dramatically aggravated by BAY60-6583 and alleviated by PSB1115. In animal experiments, rats were treated with 2 mg/kg BAY60-6583 and 10 mg/kg PSB1115, followed by gastric ulcer modeling 30 min later. In HP-infected rats, increased ulcer area, elevated pepsin activity, increased hematoxylin and eosin (HE) pathological scores, increased MDA levels, and decreased SOD activity were observed, which were further aggravated by BAY60-6583 and ameliorated by PSB1115. Finally, the effects of A2BR activation on apoptosis, migration, oxidative stress, and p38MAPK signaling in HP-infected GES-1 cells were reversed by an inhibitor of the p38MAPK pathway. Collectively, A2BR facilitated the pathogenesis of HP-induced gastric ulcers by inducing oxidative stress through p38MAPK activation.

Research progress in steroidal saponins from the genus Polygonatum: Chemical components, biosynthetic pathways and pharmacological effects

The genus Polygonatum Mill. belongs to the Liliaceae family, which is widely distributed all over the world. Modern studies have found that Polygonatum plants are very rich in chemical compounds such as saponins, polysaccharides and flavonoids. Steroidal saponins are the most commonly studied saponins in the genus Polygonatum and a total of 156 compounds have been isolated from 10 species of the genus. These molecules possess antitumor, immunoregulatory, anti-inflammatory, antibacterial, antiviral, hypoglycemic, lipid-lowering and anti-osteoporotic activities. In this review, we summarize recent advances in studies of the chemical constituents of steroidal saponins from Polygonatum, including their structural characteristics, possible biosynthetic pathways and pharmacological effects. Then, the relationship between the structure and some physiological activities is considered. This review aims to provide reference for further exploitation and utilization of the genus Polygonatum.

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

RATIONALE

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

METHODS

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

RESULTS

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

CONCLUSION

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

ALCAM Deficiency Alleviates LPS-Induced Acute Lung Injury by Inhibiting Inflammatory Response

We investigated the effects and underlying mechanisms of activated leukocyte adhesion molecule (ALCAM) on acute lung injury (ALI) by using lipopolysaccharide (LPS)-induced ALI animal model and LPS-induced inflammation in vitro. In LPS-stimulated mice, ALCAM deficiency relieved lung injury, which manifested as reduced pathological changes in the lung tissue, reduced pulmonary edema, and reduced vascular permeability. Furthermore, we demonstrated that ALCAM deficiency reduced the infiltration of inflammatory cells, including neutrophil, eosinophil, and macrophages; the release of inflammatory cytokines, including IL-1β, IL-6, TNF-α, and COX2; and reduced the protein level of TLR4/NF-κB pathway (TLR4, MyD88, p-IkBɑ, and p-NF-κB p65). We also demonstrated that ALCAM deficiency reduced the expression of oxidative stress-related proteins (Nrf-2, HO-1, and NQO-1) and endoplasmic reticulum stress-related proteins (CHOP, GRP78, ATF-6, and p-eIF2ɑ). In addition, in LPS-induced inflammation in vitro, ALCAM overexpression promoted inflammatory response, oxidative stress, and ER stress. We established that ALCAM deficiency can suppress the ALI process by reducing inflammatory response, oxidative stress, and endoplasmic reticulum stress.

Effect of the number of sugar units on the interaction between diosgenyl saponin and membrane lipids

Saponin is the main bioactive component of the Dioscorea species, which are traditionally used for treating chronic diseases. An understanding of the interaction process of bioactive saponins with biomembranes provides insights into their development as therapeutic agents. The biological effects of saponins have been thought to be associated with membrane cholesterol (Chol). To shed light on the exact mechanisms of their interactions, we investigated the effects of diosgenyl saponins trillin (TRL) and dioscin (DSN) on the dynamic behavior of lipids and membrane properties in palmitoyloleolylphosphatidylcholine (POPC) bilayers using solid-state NMR and fluorescence spectroscopy. The membrane effects of diosgenin, a sapogenin of TRL and DSN, are similar to those of Chol, suggesting that diosgenin plays a major role in membrane binding and POPC chain ordering. The amphiphilicity of TRL and DSN enabled them to interact with POPC bilayers, regardless of Chol. In the presence of Chol, the sugar residues more prominently influenced the membrane-disrupting effects of saponins. The activity of DSN, which bears three sugar units, led to perturbation and further disruption of the membrane in the presence of Chol. However, TRL, which bears one sugar residue, increased the ordering of POPC chains while maintaining the integrity of the bilayer. This effect on the phospholipid bilayers is similar to that of cholesteryl glucoside. The influence of the number of sugars in saponin is discussed in more detail.

SIRT6 attenuates LPS-induced inflammation and apoptosis of lung epithelial cells in acute lung injury through ACE2/STAT3/PIM1 signaling

BACKGROUND

Acute lung injury (ALI) is a severe and fatal respiratory disease. SIRT6 exerts pivotal activities in the process of lung diseases, but whether SIRT6 impacts ALI has not been covered.

METHODS

Lentivirus recombinant expressing vector SIRT6 gene (Lent-SIRT6) was constructed in mice, and there were control, lipopolysaccharide (LPS), LPS + Vehicle, and LPS + Lent SIRT6 groups. RT-qPCR and western blot detected SIRT6 expression in lung tissues. HE staining observed pathological alternations in lung tissues. Wet-to-dry ratio of the lungs was then measured. The cell count of bronchoalveolar lavage fluid (BALF) was evaluated. Serum inflammation was examined with enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and western blot were to measure apoptosis. Western blot tested the expression of ACE2/STAT3/PIM1 signaling-associated factors. At the cellular level, LPS was used to induce lung epithelial cells BEAS-2B to establish cell injury models. SIRT6 was overexpressed and ACE2 expression was inhibited by cell transfection, and the mechanism of SIRT6 in LPS-induced lung injury model was further explored by Cell Counting Kit-8 (CCK-8), western blot, quantitative reverse-transcription polymerase chain reaction, TUNEL, and other techniques.

RESULTS

The results of animal experiments showed that SIRT6 overexpression could reduce LPS-induced lung pathological injury, pulmonary edema, and BALF cell ratio and attenuate LPS-induced inflammatory response and cell apoptosis. In the above process, ACE2, STAT3, p-STAT3, and PIM1 expression were affected. In cell experiments, SIRT6 expression was reduced in LPS-induced BEAS-2B cells. Inhibition of ACE2 expression could reverse the inhibitory effect of SIRT6 overexpression on ACE2/STAT3/PIM1 pathway, and cellular inflammatory response and apoptosis.

CONCLUSION

SIRT6 eased LPS-evoked inflammation and apoptosis of lung epithelial cells in ALI through ACE2/STAT3/PIM1 signaling.

Saponins: Research Progress and Their Potential Role in the Post-COVID-19 Pandemic Era

In the post-COVID-19 pandemic era, the new global situation and the limited therapeutic management of the disease make it necessary to take urgent measures in more effective therapies and drug development in order to counteract the negative global impacts caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its new infectious variants. In this context, plant-derived saponins-glycoside-type compounds constituted from a triterpene or steroidal aglycone and one or more sugar residues-may offer fewer side effects and promising beneficial pharmacological activities. This can then be used for the development of potential therapeutic agents against COVID-19, either as a therapy or as a complement to conventional pharmacological strategies for the treatment of the disease and its prevention. The main objective of this review was to examine the primary and current evidence in regard to the therapeutic potential of plant-derived saponins against the COVID-19 disease. Further, the aim was to also focus on those studies that highlight the potential use of saponins as a treatment against SARS-CoV-2. Saponins are antiviral agents that inhibit different pharmacological targets of the virus, as well as exhibit anti-inflammatory and antithrombotic activity in relieving symptoms and clinical complications related to the disease. In addition, saponins also possess immunostimulatory effects, which improve the efficacy and safety of vaccines for prolonging immunogenicity against SARS-CoV-2 and its infectious variants.

Tetramethylpyrazine ameliorates acute lung injury by regulating the Rac1/LIMK1 signaling pathway

Acute lung injury (ALI) is a respiratory disorder characterized by severe inflammation of the alveoli and lung parenchyma. Tetramethylpyrazine (TMP), the main active compound in Ligusticum chuanxiong Hort (LC), can protect against lipopolysaccharide (LPS)-induced ALI. Our study aimed to investigate how TMP protects the endothelial cell barrier in pulmonary capillaries. We administered TMP intraperitoneally at different doses and found that acute lung injury in mice was improved, but not in a dose-dependent manner. TMP toxicity was tested in vitro. We observed that LPS-induced cytoskeletal remodeling was inhibited by TMP. Murine ALI was induced as follows: For the 1st hit, LPS (2 mg/kg) was injected intraperitoneally; after 16 h, for the 2nd hit, LPS (4 mg/kg) was instilled intratracheally. The mice in treatment groups had TMP or dexamethasone administered intraperitoneally 30 min prior to the 1st hit and 30 min past the 2nd hit. Mice were euthanized 24 h after the last injecting. We measured protein and mRNA levels using enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase real-time PCR (RT-qPCR), respectively. The ultrastructural analysis was performed with transmission electron microscopy (TEM) and the cytoskeleton was observed by immunofluorescence. Immunohistochemistry and Western blotting were used to detect protein expression in the Rac1/LIMK1/ZO-1/occludin signal pathway. The results showed that TMP treatment decreased inflammatory cell infiltration and alleviated LPS-induced damage in lung tissue. Also, TMP significantly inhibited the Rac1/LIMK1/ZO-1/occludin signaling pathway. Our findings show that using TMP during sepsis can protect the pulmonary microvascular endothelial cell barrier and suppress inflammation. Therefore, TMP may have a promising therapeutic role in preventing acute lung injury from sepsis.

Oxidative stress and immune response of hepatopancreas in Chinese mitten crab Eriocheir sinensis under lipopolysaccharide challenge

Chinese mitten crab (Eriocheir sinensis; H. Milne Edwards, 1853) is one of the important farmed crustaceans in China. Lipopolysaccharide (LPS), as a harmful factor, is prone to occur during the farming process of crabs. Aiming to test the hypothesis that damage degrees of the hepatopancreas in E. sinensis is correlated to LPS concentrations, in this study, E. sinensis were injected with LPS (50 μg/kg, and 500 μg/kg) and analyzed for the activity of antioxidant and immune-related enzymes, immune-related gene expression, and histopathological of hepatopancreas. As result, the hepatopancreas of E. sinensis immune-related genes, i.e., Dorsal, HSP90, Toll2, TLRs, Tube, and proPO, were significantly affected by LPS challenge. Among immune-related genes, Dorsal and proPO might play key roles in combating the LPS challenge. The activity of CAT gradually decreased with the increase of time, and the total antioxidant capacity was decreased after LPS challenge, indicating the inhibition of LPS on the antioxidant system. Interestingly, the decreasing trend of AKP and ACP activity suggested the immune system of crabs was affected by LPS challenge. The hepatopancreas section showed that the damage degree of hepatopancreas was different under the challenge of LPS with different concentrations, and the damage degree was proportional to the concentration. Our findings provide useful information for understanding the mechanism of hepatopancreas injury of E. sinensis induced by LPS infection.

Protein-coated microplastics corona complex: An underestimated risk of microplastics

Traditionally, toxicity of microplastics is ascribed to the chemicals adsorbed on them. However, microplastics can also interact with biomolecules, such as secretory proteins from aquatic organisms, and form protein-coated microplastics corona complex with unknown toxic effects. Here, we investigated the toxic effects of polystyrene microplastics (PS) and bovine serum albumin (BSA) coated PS corona complex (PS + BSA) on adult zebrafish (Danio rerio) intestines. The food intake ratio, accumulation and distribution of microplastics, histopathological changes, and molecular effects related to the antioxidant system in the intestine were studied. For the first time, we observed that PS + BSA aggregated on the inner surface of the zebrafish intestine, whereas PS dispersed. The aggregation of PS + BSA resulted in increased microplastics accumulation and longer residence time in the zebrafish intestine, which inhibited food intake and generated reactive oxygen species (ROS) in the intestine. Furthermore, the functions of the Keap1-Nrf2-ARE antioxidant signaling pathway and the activation of antioxidant enzymes were significantly affected by PS + BSA after a 21-day exposure. Ultimately, a higher accumulation of ROS and stronger inhibition of antioxidants led to more severe intestinal injury. These results suggest that the increased toxicity of protein-coated microplastics corona complex may be affected by oxidative damage and can result in the inhibition of digestion due to their aggregation and longer residence time in the intestine. Therefore, the ecological risk of microplastics may be underestimated owing to the interactive mechanisms of microplastics and protein coronas.

BP5 alleviates endotoxemia-induced acute lung injury by activating Nrf2 via dual regulation of the Keap1-Nrf2 interaction and the Akt (Ser473)/GSK3β (Ser9)/Fyn pathway

Oxidative stress and inflammation play a crucial role in the pathogenesis of acute lung injury (ALI). Previously, pentapeptide bursopentin (BP5, Cys-Lys-Arg-Val-Tyr) was reported to possess significant antioxidant activity and inhibit lipopolysaccharides (LPS)-induced NF-κB activation in vitro, whereas little is known about its effects in vivo. In this study, we explored the effects of BP5 on endotoxemia-induced ALI in mice and the underlying molecular mechanisms. Our studies revealed that BP5 markedly improved survival and effectively alleviated lung injury by reducing overoxidation and excessive inflammatory response in endotoxemia mice. In LPS-stimulated mouse primary macrophages and RAW 264.7 cells, BP5 also exhibited antioxidant and anti-inflammatory properties by enhancing Nrf2 activation. Importantly, these beneficial effects were abolished by Nrf2 knockdown. To further elucidate the underlying mechanisms, we performed localized surface plasmon resonance (LSPR) assays, molecular docking, together with cell-based studies, and found that BP5 inhibited the Keap1-Nrf2 interaction to promote Nrf2 nuclear translocation and activation. Moreover, BP5-induced Nrf2 activation was shown to be accompanied by an increase in the phosphorylation of Akt (at Ser473) and GSK3β (at Ser9), and a decrease in Fyn nuclear accumulation both in vitro and in vivo. Pharmacologically inhibiting phosphorylation of Akt and GSK3β obviously enhanced Fyn nuclear accumulation in RAW 264.7 cells, which partially attenuated the promoting effect of BP5 on Nrf2 nuclear accumulation and activation. Furthermore, In Nrf2^-/- mice, the protective effects of BP5 on the endotoxemia-induced ALI in WT mice were largely vanished. Our findings indicated that BP5 effectively protected endotoxemia-induced ALI against oxidative stress and inflammatory response, which are largely dependent on activation of the Nrf2 pathway. Underlying mechanisms include dual regulation of the Keap-Nrf2 interaction and the Akt (Ser473)/GSK3β (Ser9)/Fyn pathway.

1,2,3,4,6-O-Pentagalloylglucose Protects against Acute Lung Injury by Activating the AMPK/PI3K/Akt/Nrf2 Pathway

An acute lung injury (ALI) is a serious lung disease with a high mortality rate, warranting the development of novel therapies. Previously, we reported that 1,2,3,4,6-O-pentagalloylglucose (PGG) could afford protection against ALI, however, the PGG-mediated protective effects remain elusive. Herein, PGG (60 and 30 mg/kg) markedly inhibited the lung wet/drug weight ratio and attenuated histological changes in the lungs (p < 0.05). A pretreatment with PGG (60 and 30 mg/kg) reduced the number of total leukocytes and the production of pro-inflammatory cytokines IL-6 and IL-1β in bronchoalveolar lavage fluid (p < 0.05). In addition, PGG (60 and 30 mg/kg) also attenuated oxidative stress by reducing the formation of formation and the depletion of superoxide dismutase to treat an ALI (p < 0.05). To further explore the PGG-induced mechanism against an ALI, we screened the PGG pathway using immunohistochemical analysis, immunofluorescence assays, and Western blotting (WB). WB revealed that the expression levels of adenosine monophosphate-activated protein kinase phosphorylation (p-AMPK), phosphoinositide 3-kinase (PI3K), protein kinase B phosphorylation (P-Akt), and nuclear factor erythroid 2-related factor (Nrf2) were significantly higher in the PGG group (60 and 30 mg/kg) than in the lipopolysaccharide group (p < 0.05); these findings were confirmed by the immunohistochemical and immunofluorescence results. Accordingly, PGG could be effective against an ALI by inhibiting inflammation and oxidative stress via AMPK/PI3K/Akt/Nrf2 signaling, allowing for the potential development of this as a natural drug against an ALI.

N-phenethyl-5-phenylpicolinamide alleviates inflammation in acute lung injury by inhibiting HIF-1α/glycolysis/ASIC1a pathway

AIMS

Acute lung injury (ALI) is triggered by an acute inflammatory response. Lipopolysaccharide (LPS) is recognized as an important participant in the pathogenesis of sepsis, which may induce ALI. N-phenethyl-5-phenylpicolinamide (N5P) is a newly synthesized HIF-1α inhibitor. The purpose of the present study was to investigate the potential protective effects of N5P on LPS-induced ALI and the underlying mechanisms.

MAIN METHODS

In vivo experiment, the ALI rat model was induced by intratracheal injection of LPS, and various concentrations of N5P were injected intraperitoneally before LPS administration. In vitro experiment, RAW264.7 macrophages were administrated LPS and N5P to detect inflammatory cytokine changes. HIF-1α overexpression plasmid (HIF1α-OE) and granulocyte-macrophage colony-stimulating factor (GM-CSF), a glycolysis agonist, were used to examine the relationship between the HIF-1α/glycolysis/ASIC1a pathway.

KEY FINDINGS

Pretreatment with N5P inhibited not only the histopathological changes that occurred in the lungs but also lung dysfunction in LPS-induced ALI. N5P also decreased the levels of lactic acid in lung tissue and arterial blood, and inflammatory factors IL-1β and IL-6 levels in serum. LPS increased HIF-1α, glycolysis proteins GLUT1, HK2, ASIC1a, IL-1β, IL-6, and these changes were reversed by N5P in primary alveolar macrophages and RAW264.7 macrophages. Overexpression of HIF-1α significantly increased glycolysis genes and ASIC1a as well as inflammatory cytokines. Excessive glycolysis levels weaken the ability of N5P to inhibit inflammation.

SIGNIFICANCE

N5P may alleviate inflammation in ALI through the HIF-1α/glycolysis/ASIC1a signaling pathway. The present findings have provided pertinent information in the assessment of N5P as a potential, future therapeutic drug for ALI.

Herbal medicine in the treatment of COVID-19 based on the gut-lung axis

Respiratory symptoms are most commonly experienced by patients in the early stages of novel coronavirus disease 2019 (COVID-19). However, with a better understanding of COVID-19, gastrointestinal symptoms such as diarrhea, nausea, and vomiting have attracted increasing attention. The gastrointestinal tract may be a target organ of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The intestinal microecological balance is a crucial factor for homeostasis, including immunity and inflammation, which are closely related to COVID-19. Herbal medicine can restore intestinal function and regulate the gut flora structure. Herbal medicine has a long history of treating lung diseases from the perspective of the intestine, which is called the gut-lung axis. The physiological activities of guts and lungs influence each other through intestinal flora, microflora metabolites, and mucosal immunity. Microecological modulators are included in the diagnosis and treatment protocols for COVID-19. In this review, we demonstrate the relationship between COVID-19 and the gut, gut-lung axis, and the role of herbal medicine in treating respiratory diseases originating from the intestinal tract. It is expected that the significance of herbal medicine in treating respiratory diseases from the perspective of the intestinal tract could lead to new ideas and methods for treatment.

Graphical abstract

http://links.lww.com/AHM/A33.

Tailored Extracellular Vesicles: Novel Tool for Tissue Regeneration

Extracellular vesicles (EVs) play an essential part in multiple pathophysiological processes including tissue injury and regeneration because of their inherent characteristics of small size, low immunogenicity and toxicity, and capability of carrying a variety of bioactive molecules and mediating intercellular communication. Nevertheless, accumulating studies have shown that the application of EVs faces many challenges such as insufficient therapeutic efficacy, a lack of targeting capability, low yield, and rapid clearance from the body. It is known that EVs can be engineered, modified, and designed to encapsulate therapeutic cargos like proteins, peptides, nucleic acids, and drugs to improve their therapeutic efficacy. Targeted peptides, antibodies, aptamers, magnetic nanoparticles, and proteins are introduced to modify various cell-derived EVs for increasing targeting ability. In addition, extracellular vesicle mimetics (EMs) and self-assembly EV-mimicking nanocomplex are applied to improve production and simplify EV purification process. The combination of EVs with biomaterials like hydrogel, and scaffolds dressing endows EVs with long-term therapeutic efficacy and synergistically enhanced regenerative outcome. Thus, we will summarize recent developments of EV modification strategies for more extraordinary regenerative effect in various tissue injury repair. Subsequently, opportunities and challenges of promoting the clinical application of engineered EVs will be discussed.

miR-135a-5p Suppresses TBK1 and Activates NRF2/TXNIP Antioxidant Pathway in LPS-Driven ALI in Mice

Objective. Acute inflammation and oxidative stress are present in large numbers in patients with acute lung injury (ALI). This investigation probed miR-135a-5p/TBK1 axis within ALI together with its new therapeutic target. Methods. MLE-12 cultures were treated with lipopolysaccharide (LPS) and transfected with miR-135a-5p mimics or TBK1 vector. An ALI mouse model was also established. Analysis was done on the relationships between TBK1 and miR-135a-5p. Inflammatory components, SOD, MDA, and ROS content were all assessed. Results. Obvious inflammatory lesions were observed in lung tissues of ALI mice. Overexpression of miR-135a-5p or TBK1 knockdown remarkably decreased IL-1β, IL-6, and TNF-α serum concentrations and increased IL-10 level within lung tissues. Activated NRF2/TXNIP pathway and oxidative stress were additionally found within ALI murines, which were regulated by miR-315a-5p and TBK1. Further research revealed that miR-135a-5p negatively regulated TBK1 expression to mediate proinflammatory response and oxidative stress. Conclusion. miR-135a-5p targeted TBK1 to regulate inflammatory/oxidative stress responses in ALI. Such results might bring a new potential target for ALI treatment.

Hydrogen-rich and hyperoxygenate saline inhibits lipopolysaccharide-induced lung injury through mediating NF-κB/NLRP3 signaling pathway in C57BL/6 mice

BACKGROUND

Background: Acute lung injury (ALI) is one kind of frequently occurred emergency in Intensive Care Unite with a high mortality. The underlying causes are uncontrolled inflammatory reactions and intractable hypoxemia, which are difficult to control and improve. In the past 10 years, gas medical studies have found that both hydrogen molecules and oxygen molecules have protective effects on acute lung injury by improving inflammatory reactions and hypoxia, respectively. Oxygen is an oxidant and hydrogen is an antioxidant. In this study, we investigated the combined effect of above two-gas molecular on lipopolysaccharide (LPS) -induced acute lung injury.

METHODS

To clarify whether the combination of hydrogen and oxygen could increase or cancel out the protective effect, an ALI mice model induced by intraperitoneal injection of LPS was established, and the degree of lung tissue and mitochondria damage was evaluated based on the pathological sections, inflammatory factors, wet-dry ratio, bronchoalveolar lavage fluid (BALF). Immunohistochemistry, electron microscopy, western blotting and other detection methods also used to evaluate the therapeutic effect on acute lung injury model.

RESULTS

We observed that the combined protective effect of hydrogen and oxygen was superior to their respective protective effects, and the specific molecular mechanisms of the two therapies might be different.

CONCLUSION

Hydrogen plays a more important role in the inflammatory and anti-apoptosis mechanisms, while oxygen improves hypoxia of the body, and thus, its molecular mechanism may be closely associated to the hypoxia pathways.

Protective effect of Amomum Roxb. essential oils in lipopolysaccharide-induced acute lung injury mice and its metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Several Amomum species are commonly used in food as flavoring agents and traditional Chinese medicine to treat inflammation-related diseases.

AIM OF THE STUDY

This study aims to investigate the protective effects of Chinese herbal medicines, including six Amomum Roxb. essential oils (AEOs), against acute lung injury (ALI) induced by lipopolysaccharide (LPS) in mice.

MATERIALS AND METHODS

The compositions of AEOs were analyzed using gas chromatography - mass spectrometry. RAW264.7 cells were treated with AEOS (0-100 μg/mL) and stimulated with LPS. C57 mice received AEOs (100 mg/kg) via atomization system for seven consecutive days, and then, intratracheal instillation of LPS was applied to establish an in vivo model of acute lung injury.

RESULTS

We identified three AEOs demonstrating anti-inflammatory effects and amelioration of LPS-induced lung tissue pathological damage. Furthermore, we found that these AEOs reduced lung wet/dry weight ratios and protein concentrations in the bronchoalveolar lavage fluid of mice with LPS-induced ALI. Additionally, AEOs reduced the levels of malondialdehyde, TNF-α, IL-6, and IL-1β but increased the levels of superoxide dismutase and catalase in lung tissue, alveolar lavage fluid, and serum samples. We also found that these three AEOs affected proteins related to the TLR4/Myd88/NF-κB pathway.

CONCLUSIONS

In summary, our findings revealed that AEOs ameliorate inflammatory and oxidative stress in mice with ALI through the TLR4/Myd88/NF-κB pathway.

Bioactive phenolics fraction of Hedera helix L. (Common Ivy Leaf) standardized extract ameliorates LPS-induced acute lung injury in the mouse model through the inhibition of proinflammatory cytokines and oxidative stress

Hedera helix L. (family Araliaceae) is classified as a conventional plant used as a medicinal product in the cure and prevention of upper respiratory tract inflammation and infection due to its secretolytic and broncholytic effects. Our research was conducted to authenticate the anti-inflammatory effect of ivy leaves extract in the prevention of acute lung injury (ALI) caused by intranasal administration of lipopolysaccharides (LPS). In-vitro antimicrobial, anti-inflammatory, and anti-oxidant were evaluated, in addition to the in-vivo acute lung inflammation model induced by LPS in mice. The animals were divided into seven groups randomly (each group containing 10 mice): control negative (saline only), control positive (LPS group), standard (Dexamethasone 2 mg/kg), ethanolic ivy leaves extract (EIE, 100 mg/kg), ethanolic ivy leaves extract (EIE, 200 mg/kg), saponin rich fraction (SRF, 100 mg/kg) and phenolic rich fraction (PRF, 100 mg/kg). Right lungs were homogenized to determine the levels of SOD, MDA, catalase, IL-10, TNF-α, NO, IL-1β, IL-6, PGE2, and MPO. Left lungs were excised for histopathology and histomorphometry. Immunohistochemistry of Cox-2 and TNF-α levels were measured. Additionally, Western blotting was used to determine the levels of phosphorylated MAPK. Also, the ethanolic extract was also standardized through HPLC analysis for its content of rutin.The data showed that the oral supplementation with EIE, 200 mg/kg significantly (P < 0.05) decreased the pro-inflammatory mediators, and oxidative stress biomarkers induced by LPS. Interestingly, the phenolics showed promising activity, therefore they are responsible for the action. In conclusion, the standardized ivy leaf extract could be advised for acute lung injury for its antimicrobial, anti-oxidant, and anti-inflammatory activities.

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Ivy leaf is a traditional perennial edible herb used as an anti-inflammatory agent for respiratory disorders.

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The plant significantly reduced the serum oxidative stress biomarkers and inflammatory cytokines in the in-vivo acute lung inflammation model induced by LPS.

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Also, it had antimicrobial activity.

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Phenolics not saponins are responsible for the activity of the plant.

Knockdown of circRNA Paralemmin 2 Ameliorates Lipopolysaccharide-induced Murine Lung Epithelial Cell Injury by Sponging miR-330-5p to Reduce ROCK2 Expression

Previous data have reported the high expression of circRNA paralemmin 2 (circPALM2) in mice with acute lung injury (ALI). However, the role of circPALM2 in ALI pathogenesis remains unclear. The study aims to reveal the function of circPALM2 in ALI and the underlying mechanism. C57BL/6 J mice and murine lung epithelial-12 (MLE-12) cells were treated with lipopolysaccharide (LPS) to simulate ALI mouse and ALI cell models, respectively. Lung injury score and lung wet-to-dry ratio assays were used to evaluate the ALI mouse model. Quantitative real-time polymerase chain reaction and Western blot assays were implemented to analyze the expressions of circPALM2, microRNA-330-5p (miR-330-5p), rho-associated coiled-coil containing protein kinase 2 (ROCK2), and apoptosis-related markers. Cell viability, apoptosis, and the production of inflammatory cytokines were investigated by cell counting kit-8, flow cytometry, and enzyme-linked immunosorbent assays. The expressions of circPALM2 and ROCK2 were significantly increased, while miR-330-5p was decreased in ALI mice and LPS-induced MLE-12 cells compared with controls. LPS treatment inhibited cell viability but induced apoptosis, inflammatory cytokine production, and oxidative stress; however, these effects were attenuated after the combination of circPALM2 knockdown and LPS. CircPALM2 regulated LPS-caused MLE-12 cell damage by targeting miR-330-5p. Additionally, ROCK2, a target gene of miR-330-5p, participated in LPS-induced MLE-12 cell injury. Further, circPALM2 activated ROCK2 by associating with miR-330-5p. CircPALM2 modulated LPS-caused murine lung epithelial cell injury by the miR-330-5p/ROCK2 pathway, providing a therapeutic target for ALI.

Anti-inflammatory and modulatory effects of steroidal saponins and sapogenins on cytokines: A review of pre-clinical research

BACKGROUND

Saponins are glycosides which, after acid hydrolysis, liberate sugar(s) and an aglycone (sapogenin) which can be triterpenoid or steroidal in nature. Steroidal saponins and sapogenins have attracted significant attention as important natural anti-inflammatory compounds capable of acting on the activity of several inflammatory cytokines in various inflammatory models.

PURPOSE

The aim of this review is to collect preclinical in vivo studies on the anti-inflammatory activity of steroidal saponins through the modulation of inflammatory cytokines.

STUDY DESIGN AND METHODS

This review was carried out through a specialized search in three databases, that were accessed between September and October, 2021, and the publication period of the articles was not limited. Information about the name of the steroidal saponins, the animals used, the dose and route of administration, the model of pain or inflammation used, the tissue and experimental method used in the measurement of the cytokines, and the results observed on the levels of cytokines was retrieved.

RESULTS

Forty-five (45) articles met the inclusion criteria, involving the saponins cantalasaponin-1, α-chaconine, dioscin, DT-13, lycoperoside H, protodioscin, α-solanine, timosaponin AIII and BII, trillin, and the sapogenins diosgenin, hecogenin, and ruscogenin. The surveys were carried out in seven different countries and only articles between 2007 and 2021 were found. The studies included in the review showed that the saponins and sapogenins were anti-inflammatory, antinociceptive and antioxidant and they modulate inflammatory cytokines mainly through the Nf-κB, TLR4 and MAPKs pathways.

CONCLUSION

Steroidal saponins and sapogenins are promising compounds in handling of pain and inflammation for the development of natural product-derived drugs. However, it is necessary to increase the methodological quality of preclinical studies, mainly blinding and sample size calculation.

Oxidative stress-induced FABP5 S-glutathionylation protects against acute lung injury by suppressing inflammation in macrophages

Oxidative stress contributes to the pathogenesis of acute lung injury. Protein S-glutathionylation plays an important role in cellular antioxidant defense. Here we report that the expression of deglutathionylation enzyme Grx1 is decreased in the lungs of acute lung injury mice. The acute lung injury induced by hyperoxia or LPS is significantly relieved in Grx1 KO and Grx1^fl/flLysM^cre mice, confirming the protective role of Grx1-regulated S-glutathionylation in macrophages. Using a quantitative redox proteomics approach, we show that FABP5 is susceptible to S-glutathionylation under oxidative conditions. S-glutathionylation of Cys127 in FABP5 promotes its fatty acid binding ability and nuclear translocation. Further results indicate S-glutathionylation promotes the interaction of FABP5 and PPARβ/δ, activates PPARβ/δ target genes and suppresses the LPS-induced inflammation in macrophages. Our study reveals a molecular mechanism through which FABP5 S-glutathionylation regulates macrophage inflammation in the pathogenesis of acute lung injury.

Redox-dependent regulation plays a key role in the pathogenesis of acute lung injury, but its mechanism is unclear. Here the authors show Grx1-regulated S-glutathionylation of FABP5 controls macrophage inflammation and alleviates acute lung injury.

Exposure to carbon black nanoparticles during pregnancy aggravates lipopolysaccharide-induced lung injury in offspring: an intergenerational effect

Carbon black nanoparticles (CBNPs) are one of the most frequently used nanoparticles. Exposure to CBNPs during pregnancy (PrE to CBNPs) can directly induce inflammation, lung injury, and genotoxicity in dams and results in abnormalities in offspring. However, whether exposure to CBNPs during pregnancy enhances the susceptibility of offspring to environmental stimuli remains unknown. To address this issue, in this study, we intranasally treated pregnant mice with mock or CBNPs from gestational day (GD) 9 to GD18, and F1 and F2 offspring were normally obtained. By intratracheal instillation of mice with lipopolysaccharide (LPS) to trigger a classic animal model for acute lung injury, we intriguingly found that after LPS treatment, F1 and F2 offspring after exposure during pregnancy to CBNPs both exhibited more pronounced lung injury symptoms, including more degenerative histopathological changes, vascular leakage, elevated MPO activity, and activation of inflammation-related signaling transduction, compared with F1 and F2 offspring in the mock group, suggesting PrE to CBNPs would aggravate LPS-induced lung injury in offspring, and this effect was intergenerational. We also observed that PrE to CBNPs upregulated the mRNA expression of DNA methyltransferases (Dnmt) 1/3a/3b and DNA hypermethylation in both F1 and F2 offspring, which might partially account for the intergenerational effect. Together, our study demonstrates for the first time that PrE to CBNPs can enhance sensitivity to LPS in both F1 and F2 offspring, and this intergenerational effect may be related to DNA hypermethylation caused by CBNPs.

Novel Combined Preparation and Investigation of Bergenin-Loaded Albumin Nanoparticles for the Treatment of Acute Lung Injury: In Vitro and In Vivo Evaluations

A new method for targeting lung infections is of great interest using biodegradable nanoparticles. In this study, bergenin-loaded BSA NPs were developed against lung injury. Briefly, bergenin-loaded bovine serum albumin nanoparticles (BG@BSA NPs) were synthesized and characterized. HPLC recorded the major peak of bergenin. UV-Vis spectra had an absorbance at 376 nm. XRD revealed the presence of crystalline particles. FTIR confirmed the occurrence of functionalized molecules in the synthesized NPs. The particles were highly stable with a net negative charge of - 24.2. The morphology of NPs was determined by SEM and TEM. The mean particle size was 124.26 nm. The production of NO by NR8383 cells was decreased by BG@BSA NPs. Also, in mice, lipopolysaccharide-mediated acute lung inflammation was induced. BG@BSA NPs reduced macrophages and neutrophils in BALF and remarkably enhanced wet weight-to-dry weight (W/D) ratios and myeloperoxidase (MPO) activity. Further, BG@BSA NPs inhibited the production of inflammatory cells as well as tumor necrosis factor. The histopathological studies revealed that the damage and neutrophil infiltration were greatly inhibited by BG@BSA NPs. This indicates that BG@BSA NPs may be used to treat lung infections. Therefore, this study has given new insight into producing an active drug for the treatment of lung-associated diseases in the future.

Exosomal miR-132-3p from mesenchymal stem cells alleviated LPS-induced acute lung injury by repressing TRAF6

Exosomes isolated from mesenchymal stem cells (MSC) had shown beneficial effect on acute lung injury (ALI). However, the effective components in MSC-derived exosomes need further investigation. ALI mice model was established by lipopolysaccharide (LPS) injection. In vitro inflammatory model was established by LPS stimulation of MLE-12 cells. The cell proliferation was evaluated by EdU assay. TUNEL and Annexin V/PI were applied to evaluate the apoptosis of tissue and cell respectively. HE staining was performed to evaluate the lung injury. Transmission electronic microscope was used to observe isolated exosomes. Level of cytokines, MDA, KGF were determined by ELISA kit. Direct interaction of miR-132-3p and TRAF6 were verified by dual luciferase assay. The level of mRNA or proteins were determined by qRT-PCR or western blots respectively. TRAF6 was upregulated while miR-132-3p was downregulated in LPS-stimulated ALI model. MiR-132-3p negatively regulated TRAF6 by direct binding. MiR-132-3p potentiated proliferation and suppressed apoptosis of LPS-induced MLE-12 cells at least partly dependent on targeting TRAF6. Treatment of exosome alleviated the LPS-induced ALI in mice and LPS-induced inflammatory response in MLE-12 cells. Moreover, overexpression of miR-132-3p promoted the protective effect of exosomes in LPS-induced MLE-12 cells injury and LPS-induced ALI. Mechanically, it was suggested that miR-132-3p inactivated PI3K/Akt signalling via targeting TRAF6. In the present study, our results indicated that miR-132-3p mediated protective effect of MSC-derived exosomes on LPS-induced ALI. Exosomal miR-132-3p ameliorated LPS-induced ALI via targeting TRAF6 and inactivating PI3K/Akt signalling.

Protectin D1 protects against lipopolysaccharide-induced acute lung injury through inhibition of neutrophil infiltration and the formation of neutrophil extracellular traps in lung tissue

Protectin D1 (PD1), a DHA-derived lipid mediator, has recently been shown to possess anti-inflammatory and pro-resolving properties. To date, little is known about the effect of PD1 on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. The aim of the present study was to investigate the therapeutic effects of PD1 on LPS-induced ALI and its potential mechanisms of action. ALI was induced via an intraperitoneal injection of LPS, where PD1 (2 ng/mouse) was administered intravenously 30 min after LPS challenge. Mice were sacrificed 24 h after modeling. Lung histopathological changes were assessed using hematoxylin and eosin staining and myeloperoxidase (MPO) activity was tested using immunohistochemistry. Tumor necrosis-α and interleukin-6 levels in the bronchoalveolar lavage fluid (BALF) and serum were measured using ELISA. To detect neutrophil extracellular traps produced by infiltrated neutrophils in the lung tissue, immunofluorescence staining was performed using anti-MPO and anti-histone H3 antibodies. The results indicated that PD1 significantly attenuated histological damage and neutrophil infiltration in lung tissue, reduced the lung wet/dry weight ratio, protein concentration and proinflammatory cytokine levels in BALF and decreased proinflammatory cytokine levels in serum. Moreover, neutrophil citrullinated histone H3 (CitH3) expression was also reduced after PD1 administration. In conclusion, PD1 attenuated LPS-induced ALI in mice via inhibition of neutrophil extracellular trap formation in lung tissue. Therefore, PD1 administration may serve to be a new strategy for treating ALI.

Albiflorin alleviates cognitive dysfunction in STZ-induced rats

BACKGROUND

To explore the effect of albiflorin (AL) on streptozotocin (STZ)-induced Alzheimer's disease (AD) in rats.

METHODS

A mouse model of diabetic encephalopathy was established by intraperitoneal injection of 1%STZ. Step down test and water maze test were used to test the cognitive function of rats. Congo Red Staining was used to detect the distribution of Aβ plaques in the hippocampus of rats. Cytokine levels in serum and hippocampus were measured using ELISA. Serum insulin, oral glucose tolerance (OGTT), serum superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were measured by commercial kits. And the content of Nrf-2/HO-1/HMGB1/NF-kB in the hippocampus of diabetic rats were detected by western blot.

RESULTS AND CONCLUSION

Compared with the STZ model group, the average escape latency of rats in the AL group in the Morris water maze test was significantly shortened, and the average number of platform crossings and the ratio of distance/total swimming distance in the target quadrant were increased significantly. Staining of tissue sections and ELISA showed a decrease in Aβ plaque density in the hippocampus of rats in the AL group. And serum insulin levels of rats in the ALgroup were significantly reduced and OGTT was improved. In addition, AL could also regulate the Nrf-2/HO-1/HMGB1/NF-kB signal pathway in the hippocampus. Therefore, AL may ameliorate STZ-induced cognitive impairment in rats by regulating oxidative stress and inflammation in the brain.

Phenylethanoid Glycosides From Callicarpa kwangtungensis Chun Attenuate TNF-α-Induced Cell Damage by Inhibiting NF-κB Pathway and Enhancing Nrf2 Pathway in A549 Cells

Background: Acute lung injury (ALI) is a complicated and severe lung disease, which is often characterized by acute inflammation. Poliumoside (POL), acteoside (ACT) and forsythiaside B (FTB) are phenylethanoid glycosides (PGs) with strong antioxidant, anti-inflammatory, and anti-apoptotic properties, which are extracted from Callicarpa kwangtungensis Chun (CK). The aim of this study was to investigate the protective effects of POL, ACT, and FTB against TNF-α-induced damage using an ALI cell model and explore their potential mechanisms.

Methods and Results: MTT method was used to measure cell viability. Flow cytometry was used for detecting the apoptosis rate. Reactive oxygen species (ROS) activity was determined using fluorescence microscope. The expression of mRNA in apoptosis-related genes (Caspase 3, Caspase 8, and Caspase 9) were tested by qPCR. The effects of POL, ACT, FTB on the activities of nuclear factor erythroid-2 related factor 2 (Nrf2), nuclear factor kappa-B (NF-κB) and the expression of their downstream genes were assessed by western blotting and RT-PCR in A549 cells. In the current study, POL, ACT, and FTB dose-dependently attenuated TNF-α-induced IL-1β, IL-6 and IL-8 production, cell apoptosis, the expression of apoptosis-related genes (Caspase 3, Caspase 8, and Caspase 9) and ROS activity. POL, ACT, and FTB not only increased in the mRNA levels of antioxidative enzymes NADPH quinone oxidoreductase (NQO1), glutamate cysteine ligase catalytic subunit (GCLC), heme oxygenase (HO-1), but also decreased the mRNA levels of IL-1β, IL-6 and IL-8. Furthermore, they upregulated the expression of Keap1 and enhanced the activation of Nrf2, while decreased the expression of phosphor-IκBα (p-IκBα) and nuclear p65. In addition, no significant changes were observed in anti-inflammatory and antioxidant effects of POL, ACT, FTB following Nrf2 and NF-κB p65 knockdown.

Conclusion: Our study revealed that POL, ACT, and FTB alleviated oxidative damage and lung inflammation of TNF-α-induced ALI cell model through regulating the Nrf2 and NF-κB pathways.

Efficacy of human immunoglobulin injection and effects on serum inflammatory cytokines in neonates with acute lung injury

The present study aimed to explore the efficacy of intravenous immunoglobulin (IVIG) injection in neonates with acute lung injury (ALI) and assess its effects on serum inflammatory cytokine levels. The research subjects were 140 neonates with ALI who were evenly distributed into a control group (COG) and a study group (STG). The COG patients were treated routinely, whereas patients in the STG were administered IVIG in addition to the standard treatment received by the COG. The arterial partial pressure of oxygen (PaO₂), PaO₂/fraction of inspired oxygen (FIO₂), mechanical ventilation time and hospitalization time were compared between the two groups. ELISA was used to determine the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the patients before treatment and at 12, 24 and 36 h after treatment. The Kaplan-Meier method was used to analyze the survival of the patients, including their survival for 30 days after treatment. The patients were divided into high and low cytokine expression groups based on their mean expression levels of serum IL-6 and TNF-α before treatment. After treatment, PaO₂ and PaO₂/FiO2 were significantly higher and mechanical ventilation and hospitalization time were reduced in the STG in comparison with the COG (all P<0.001). At 12, 24 and 36 h after treatment, serum IL-6 and TNF-α levels in the STG were lower than those in the COG (both P<0.05). The 30-day survival rate after treatment was not significantly different between the two groups (P>0.05). The 30-day survival rate in the high IL-6 and high TNF-α expression COG was lower than that in the low IL-6 and low TNF-α expression COG (both P<0.05). The results of the present study indicate that IVIG may improve pulmonary gas exchange, shorten the course of disease and reduce the inflammatory response in neonates with ALI.

Tannic acid alleviates lipopolysaccharide‑induced H9C2 cell apoptosis by suppressing reactive oxygen species‑mediated endoplasmic reticulum stress

Sepsis-induced myocardial dysfunction is one of the features of multiple organ dysfunction in sepsis, which is associated with extremely high mortality and is characterized by impaired myocardial compliance. To date, there are few effective treatment options available to cure sepsis. Tannic acid (TA) is reportedly protective during sepsis; however, the underlying mechanisms by which TA protects against septic heart injury remain elusive. The present study investigated the potential effects and underlying mechanisms of TA in alleviating lipopolysaccharide (LPS)-induced H9C2 cardiomyocyte cell apoptosis. H9C2 cells were treated with LPS (15 µg/ml), TA (10 µM) and TA + LPS; control cells were treated with medium only. Apoptosis was measured using flow cytometry, reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis. Additionally, the levels of cellular reactive oxygen species (ROS), malondialdehyde and nicotinamide adenine dinucleotide phosphate were evaluated. Western blotting and RT-qPCR were also employed to detect the expression levels of endoplasmic reticulum (ER) stress-associated functional proteins. The present findings demonstrated that TA reduced the degree of LPS-induced H9C2 cell injury, including inhibition of ROS production and ER stress (ERS)-associated apoptosis. ERS-associated functional proteins, including activating transcription factor 6, protein kinase-like ER kinase, inositol-requiring enzyme 1, spliced X box-binding protein 1 and C/EBP-homologous protein were suppressed in response to TA treatment. Furthermore, the expression levels of ERS-associated apoptotic proteins, including c-Jun N-terminal kinase, Bax, cytochrome c, caspase-3, caspase-12 and caspase-9 were reduced following treatment with TA. Additionally, the protective effects of TA on LPS-induced H9C2 cells were partially inhibited following treatment with the ROS inhibitor N-acetylcysteine, which demonstrated that ROS mediated ERS-associated apoptosis and TA was able to decrease ROS-mediated ERS-associated apoptosis. Collectively, the present findings demonstrated that the protective effects of TA against LPS-induced H9C2 cell apoptosis may be associated with the amelioration of ROS-mediated ERS. These findings may assist the development of potential novel therapeutic methods to inhibit the progression of myocardial cell injury.

Vitamin D3 mitigates lipopolysaccharide-induced oxidative stress, tight junction damage and intestinal inflammatory response in yellow catfish, Pelteobagrus fulvidraco

The present study explored the possible mitigative effects of vitamin D₃ (VD₃) on lipopolysaccharide (LPS)-induced intestinal oxidative stress, inflammatory response and tight junction damage in yellow catfish, Pelteobagrus fulvidraco. Herein, four experimental groups were established by injecting yellow catfish with NaCl, LPS, VD₃ or LPS plus VD₃. The results showed that LPS induced oxidative stress and that exogenous VD₃ mitigated the adverse effects of LPS. Additionally, LPS suppressed the activity of antioxidant enzymes (Cat, Sod and Gr) and upregulated the mRNA expression of proinflammatory cytokines (Tnf-α, Il-1β, Il-8). Furthermore, the mRNA expression of "fencing" tight junctions (Claudin-1, Claudin-5, Occludin, Zo-1) was downregulated, while that of "pore-forming" tight junctions (Claudin-2, Claudin-12) was upregulated, however no effect on apoptosis genes was observed (p53, Bax, Caspase-3 and Caspase-9). These LPS-induced effects were significantly reversed by pretreatment with VD₃. Taken together, this study suggests that exogenous VD₃ substantially alleviates LPS-induced intestinal inflammation by upregulating antioxidant activity, suppressing inflammation and promoting fencing tight junctions in the intestine.

Nuclear factor-kappaB regulates the transcription of NADPH oxidase 1 in human alveolar epithelial cells

Objective

Acute lung injury (ALI) is characterized by inflammation and oxidative stress. Nuclear factor-kappaB (NF-κB) mediates the expression of various inflammation-related genes, including the NADPH oxidase family. This study aimed to identify the potential regulatory role of NF-κB on NADPH oxidases in tumor necrosis factor-α (TNF-α)-induced oxidative stress in human alveolar epithelial cells.

Methods

A549 cells were treated with TNF-α for 24 h to establish ALI cell models. RT-PCR, western blot, assessment of oxidative stress, Alibaba 2.1 online analysis, electrophoretic mobility shift assays and luciferase reporter analysis were employed to identify the potential regulatory role of NF-κB on NADPH oxidases in TNF-α-induced oxidative stress in human alveolar epithelial cells.

Results

The expression of NF-κB/p65 was notably upregulated in TNF-α-stimulated A549 cells. NF-κB knockdown by siRNA significantly inhibited the TNF-α-induced oxidative stress. Moreover, NF-κB/p65 siRNA could inhibit the activation of NOX1, NOX2 and NOX4 mRNA and protein expression in TNF-α-stimulated A549 cells. The next study demonstrated that NF-κB activated the transcription of NOX1 by binding to the -261 to -252 bp (NOX1/κB2, TAAAAATCCC) region of NOX1 promoter in TNF-α-stimulated A549 cells.

Conclusion

Our data demonstrated that NF-κB can aggravate TNF-α-induced ALI by regulating the oxidative stress response and the expression of NOX1, NOX2 and NOX4. Moreover, NF-κB could promote the NOX1 transcriptional activity via binding its promoter in TNF-α-stimulated A549 cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01464-z.

Melatonin alleviates lipopolysaccharide-induced myocardial injury by inhibiting inflammation and pyroptosis in cardiomyocytes

Background

Melatonin (MT) has been shown to protect against various cardiovascular diseases. However, the effect of MT on lipopolysaccharide (LPS)-induced myocardial injury is poorly understood. This study aims to evaluate the effects of MT on LPS-induced myocardial injury in vitro.

Methods

H9C2 cells were divided into a control group, MT group, LPS group, and MT + LPS group. The control group was treated with sterile saline solution, the LPS group received 8 µg/mL LPS for 24 h, MT + LPS cells were pretreated with 200 µmol/L MT for 2 h then with 8 µg/mL LPS for 24 h, and the MT group received only 200 µmol/L MT for 2 h. The CCK-8 assay and lactate dehydrogenase (LDH) activity assay were used to analyze cell viability and LDH release, respectively. Intracellular reactive oxygen species (ROS) and the rate of pyroptosis were measured using the fluorescent probe dichloro-dihydro-fluorescein diacetate (DCFH-DA) and propidium iodide (PI) staining, respectively. The cell supernatants were used to measure the levels of inflammatory cytokines, including IL-6, TNF-α, and IL-1β by enzyme-linked immunosorbent assay (ELISA). The protein levels of iNOS, COX-2, NF-κB, p-NF-κB, NLRP3, caspase-1, and GSDMD were detected by western blot.

Results

MT pretreatment significantly improved LPS-induced myocardial injury by inhibiting inflammation and pyroptosis in H9C2 cells. Moreover, MT inhibited the activation of the NF-κB pathway, and reduced the expression of inflammation-related proteins (iNOS and COX-2), and pyroptosis-related proteins (NLRP3, caspase-1, and GSDMD).

Conclusions

Our data suggests that MT can alleviate LPS-induced myocardial injury, providing novel insights into the treatment of sepsis-induced myocardial dysfunction.

Dexamethasone and losartan combination treatment protected cigarette smoke-induced COPD in rats

Chronic Obstructive Pulmonary Disease (COPD) is a dangerous prevalent smoking-related disease characterized by abnormal inflammation and oxidative stress and expected to be the third cause of death in the world next decade. Corticosteroids have low effects in decreasing numbers of inflammatory mediators specifically in long-term use. Our study designed to investigate the possible protective effects of combined dexamethasone (Dex) (2mg/kg) and losartan (Los) (30mg/kg angiotensin receptor blocker, it possesses antioxidant and anti-inflammatory properties in lung injury in mice) against cigarette -smoke (CS) induced COPD in rats compared with dexamethasone and losartan. Male Sprague Dawley rats (N = 40) divided into five groups (n = 8): control group, CS group, Dex group, Los group, and Dex +Los group. COPD induced in rats by CS exposure twice daily for 10 weeks. After the specified treatment period, bronchoalveolar lavage fluid (BALF) and lung tissue were collected for measurement of SOD, NO, MDA, ICAM-, MMP-9, CRP, NF-κB and histopathology scoring. Our results indicated that Los+Dex significantly prevent CS-induced COPD emphysema, congested alveoli, and elevation of lung injury parameters in BALF. They also showed a significant decrease in MDA, ICAM-1, MMP-9, CRP, and NF-κB and a significant increase in SOD and NO. In conclusion, adding Los to Dex potentiating their activity in inhibition the progression of COPD based on its activity on oxidative stress, inflammation, and NF-κB protein expression.

Protective Effects of Pterostilbene on Lipopolysaccharide-Induced Acute Lung Injury in Mice by Inhibiting NF-κB and Activating Nrf2/HO-1 Signaling Pathways

Pterostilbene (PTER) is a kind of stilbene compound with biological activity isolated from plants such as red sandalwood, blueberry and grape. It has anti-tumor, anti-bacterial, anti-oxidation and other pharmacological activities. However, the underlying mechanism of the protective effect of PTER on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remained not clarified. In this study, LPS was used to establish a mouse model of ALI. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells, and the wet-to-dry weight ratio of the lungs was measured. The activities of myeloperoxidase (MPO), antioxidant indexes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and oxidation index such as malondialdehyde (MDA) in lung tissues of mice were measured by the corresponding kits. The levels of Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), TNF-α, IL-6 and IL-1β in lung tissues of mice were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The activities of Nrf2, HO-1, p-p65 and p-IκB were determined by western blotting. The results showed that the model of LPS-induced ALI was successfully replicated, and it was found that PTER could significantly improve the pathological degree of ALI such as sustained the integrity of the lung tissue structure, alleviated pulmonary interstitial edema and alveolar wall thickening, reduced infiltrated inflammatory cells. PTER could decrease the number of inflammatory cells and obviously inhibit the increase of W/D ratio caused by LPS. PTER could also significantly reduce LPS-induced MPO and MDA, and increase LPS-decreased SOD, CAT and GSH-Px in the lungs. In addition, it was also found that PTER has the ability to decrease LPS-induced production of COX-2, iNOS, TNF-α, IL-6 and IL-1β. The underlying mechanism involved in the protective effect of PTER on ALI were via activating Nrf2 and HO-1, and inhibiting the phosphorylation of p65 and IκB. These results suggested that PTER can protect LPS-induced ALI in mice by inhibiting inflammatory response and oxidative stress, which provided evidence that PTER may be a potential therapeutic candidate for LPS-induced ALI intervention.

BC and 1,4NQ-BC up-regulate the cytokines and enhance IL-33 expression in LPS pretreatment of human bronchial epithelial cells☆

Black carbon (BC) reacts with different substances to form secondary pollutants called aged black carbon, which causes inflammation and lung damage. BC and aged BC may enhance IL-33 in vivo, which may be derived from macrophages. The pro-inflammatory effect of IL-33 makes it essential to determine the source of IL-33, so it guides us to explore how to alleviate lung injury. In this study, a human bronchial epithelial cell line of 16HBE cells was selected, and aged BC (1,4-NQ coated BC and ozone oxidized BC) was used. We found that both BC and aged BC were able to up-regulate the mRNA expression of IL-1β, IL-6, and IL-8 except IL-33. However, the Mitogen-activated protein kinases (MAPKs) and Phosphatidylinositol 3-kinase (PI3K)/Protein kinase B (AKTs) pathways remained inactive. After pretreatment with Lipopolysaccharide (LPS), IL-33 mRNA expression was significantly increased in 16HBE cells and MAPKs and PI3K/AKT were activated. These results suggested that MAPKs and PI3K/AKT pathways were involved in the elevation of IL-33. Furthermore, epithelial cells are unlikely to be the source of lung inflammation caused by elevated IL-33 in BC and aged BC.

In vitro and in vivo anti-inflammatory effect of Zaluzanin D isolated from Achillea acuminate

The present study was investigated to verify anti-inflammatory and immune regulation effect of Zaluzanin D on LPS-induced macrophages and acute lung injury. NR8383 macrophages were pre-treated with Zaluzanin D and stimulated by LPS. Zaluzanin D reduced the production of nitric oxide in NR8383 macrophages and decreased the secretions of inflammatory cytokines. In addition, intravenous of Zaluzanin D to LPS-induced rats reduced the infiltrations of macrophages into BALF and the histological inflammatory changes in lung tissues. Furthermore, Z.D inhibited lipid peroxidation and effectively recruit the anti-oxidative defense system, regulated the levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the lungs by inhibitory expression of nuclear factor-kappa B pathway. These findings suggested that Zaluzanin D attenuated pulmonary inflammatory responses by inhibiting the expression of diverse inflammatory mediators in vitro and in vivo.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

JNK‑IN‑8 treatment alleviates lipopolysaccharide‑induced acute lung injury via suppression of inflammation and oxidative stress regulated by JNK/NF‑κB signaling

JNK serves critical roles in numerous types of inflammation- and oxidative stress-induced disease, including acute lung injury (ALI). JNK-IN-8 is the first irreversible JNK inhibitor that has been described. However, whether JNK-IN-8 can prevent lipopolysaccharide (LPS)-induced ALI by inhibiting JNK activation and its downstream signaling is poorly understood. The objective of the present study was to investigate the specific therapeutic effects of JNK-IN-8 on LPS-induced ALI and the molecular mechanisms involved. JNK-IN-8 attenuated myeloperoxidase activity, malondialdehyde and superoxide dismutase content and the lung wet/dry ratio, and improved the survival rate following lethal injection of LPS. Additionally, JNK-IN-8 decreased bronchoalveolar lavage fluid protein levels, lactate dehydrogenase activity, neutrophil infiltration and the number of macrophages (as demonstrated by flow cytometry), as well as the production of TNF-α, IL-6 and IL-1β (as evaluated via ELISA). In addition, reverse transcription-quantitative PCR and ELISA showed that JNK-IN-8 attenuated LPS-induced inflammatory cytokine production and oxidative stress in primary murine peritoneal macrophages and RAW264.7 cells in vitro. Furthermore, the present study demonstrated that the JNK/NF-κB signaling pathway was involved in the therapeutic effect of JNK-IN-8 against LPS-induced injury both in vivo and in vitro. In conclusion, these findings indicated that JNK-IN-8 had a therapeutic effect on LPS-induced ALI in mice. The mechanism may be associated with inhibition of the JNK/NF-κB signaling pathway. JNK-IN-8 may be a potential therapeutic agent for the treatment of ALI.

miR-642a-5p partially mediates the effects of lipopolysaccharide on human pulmonary microvascular endothelial cells via eEF2

Inhalation or systemic administration of lipopolysaccharide (LPS) can induce acute pulmonary inflammation and lung injury. The pulmonary vasculature is composed of pulmonary microvascular endothelial cells (PMVECs), which form a semiselective membrane for gas exchange. The miRNA miR‐642a‐5p has previously been reported to be up‐regulated in patients with acute respiratory distress syndrome; thus, here, we examined whether this miRNA is involved in the effects of LPS on PMVECs. The levels of miR‐642a‐5p and mRNA encoding eukaryotic elongation factor 2 (eEF2) were detected by quantitative RT‐PCR. Moesin and eEF2 protein levels were tested by western blot assay. Dual‐luciferase reporter assay was used to examine the relationship between miR‐642a‐5p and eEF2. Cell viability was assessed using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, and cell permeability was analyzed using the transendothelial electrical resistance assay. We report that miR‐642a‐5p levels are significantly up‐regulated in LPS‐stimulated PMVECs, and miR‐642a‐5p contributes to LPS‐induced hyperpermeability and apoptosis of PMVECs. LPS treatment results in down‐regulation of eEF2 in PMVECs. Overexpression of eEF2, a direct target of miR‐642a‐5p, inhibited the effect of LPS on PMVECs. miR‐642a‐5p promoted LPS‐induced hyperpermeability and apoptosis by targeting eEF2. Thus, miR‐642a‐5p and eEF2 may serve as potential targets for acute lung injury/acute respiratory distress syndrome diagnosis or treatment.

Protective effects of HY1702 on lipopolysaccharide-induced mild acute respiratory distress syndrome in mice

Acute respiratory distress syndrome is an inflammatory disease with no effective pharmacological treatment. We investigated the therapeutic effect of HY1702, a new small molecule diterpene obtained from the processing and modification of Glaucocalyxin A and may exhibit anti-inflammatory activity. Specifically, we studied the anti-inflammatory effects of HY1702 on lipopolysaccharide-induced inflammatory responses in RAW264.7 and THP-1 cells in vitro and its protective efficacy on lipopolysaccharide-induced mild acute respiratory distress syndrome in mice.

Our results showed that HY1702 significantly decreased lipopolysaccharide-induced inflammatory cytokine expression in RAW264.7 and THP-1 cells and attenuated the secretion of nitric oxide and prostaglandin E2 by down-regulating the expression of inducible nitric oxide synthase and cyclooxygenase 2 in RAW264.7 cells. In mice with lipopolysaccharide-induced mild acute respiratory distress syndrome, HY1702 alleviated histological alterations in the lungs and reduced the alveolar cavity protein leakage and inflammatory cytokine expression in murine bronchial alveolar lavage fluid. HY1702 decreased the myeloperoxidase activity and lung wet to dry weight ratio. In our mechanism studies in lipopolysaccharide-exposed RAW264.7 cells, HY1702 suppressed the inflammation stimulated by lipopolysaccharide through inhibiting phosphorylation of inhibitor of nuclear factor κB kinase subunit α/β (IKKα/β) and inhibitor of nuclear factor κB subunit α (IκBα), further affecting the nuclear transfer of phosphorylated p65. Meanwhile, phosphorylation of p38 mitogen-activated protein (MAP) kinase and extracellular signal-regulated kinase (ERK) was inhibited. These data suggest that HY1702 can reduce inflammation on lipopolysaccharide-stimulated macrophages and attenuate the symptoms of mild acute respiratory distress syndrome in a murine model by regulating the nuclear factor κB and MAP kinase signalling pathways.

Potential mechanism and key genes involved in mechanical ventilation and lipopolysaccharide‑induced acute lung injury

Mechanical ventilation (MV) and lipopolysaccharide (LPS) infection are common causes of acute lung injury. The aim of the present study was to identify the key genes and potential mechanisms involved in mechanical ventilation (MV) and lipopolysaccharide (LPS)-induced acute lung injury (ALI). Gene expression data of adult C57BL/6 mice with ALI induced by inhaling LPS, MV and LPS + MV were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) associated with MV, LPS and LPS + MV were screened, followed by functional enrichment analysis, protein-protein interaction network construction, and prediction of transcription factors and small molecule drugs. Finally, the expression of key genes was verified in vivo using reverse transcription-quantitative PCR. A total of 63, 538 and 1,635 DEGs were associated with MV, LPS and LPS + MV, respectively. MV-associated genes were significantly enriched in the ‘purine ribonucleotide metabolic process’. LPS and LPS + MV-associated genes were significantly enriched in ‘cellular response to cytokine stimulus’ and ‘cell chemotaxis’. All three conditions were enriched in ‘TNF signaling pathway’ and ‘IL-17 signaling pathway’. Expression levels of C-X-C motif chemokine ligand (CXCL)2, CXCL3 and CXCL10 were upregulated in the LPS and LPS + MV groups. Adenosine A2b receptor, zinc finger and BTB domain-containing 16 and hydroxycarboxylic acid receptor 2 were identified as DEGs in the MV group. Compared with the control group, Early growth response 1 and activating TF 3 was upregulated in all three groups. Similarities and differences were observed among the MV- and LPS-induced ALI, and MV may enhance the effects of LPS on gene expression. MV may affect urine ribonucleotide metabolic-related processes, whereas LPS may cause cell chemotaxis and cytokine stimulus responses in ALI progression. The inflammatory response was shared by MV and LPS. The results of the present study may provide insight into a theoretical basis for the study and treatment of ALI.