Hesperetin attenuates sepsis-induced intestinal barrier injury by regulating neutrophil extracellular trap formation via the ROS/autophagy signaling pathway

Neutrophil extracellular traps in cancer: From mechanisms to treatments

Neutrophil extracellular traps (NETs) are reticular ultrastructures released by activated neutrophils. As the reaction products of neutrophils, NETs have been identified as crucial effectors in pathogen defence and autoimmune diseases. Recently, increasing evidence suggest that this process also occurs in cancer. The formation and clearance of NETs are dynamically influenced by the tumour microenvironment, while NETs reciprocally play a dual role in either promoting or inhibiting tumour progression through their DNA scaffold, proteases and other granule-derived proteins. Given the interplay between NETs and tumours, active exploration is currently underway to harness their potential as tumour biomarkers and therapeutic targets. Here, we delve into the biochemical and immunological mechanisms underlying NETs formation within the tumour microenvironment, along with recent advances elucidating their multifaceted roles in tumourigenesis, metastasis and tumour-associated co-morbidities. Furthermore, we present emerging strategies for NETs-based tumour diagnostic approaches and therapeutics, with a special focus on the challenging questions that need to be answered within this field. KEY POINTS: The formation and clearance of NETs are dynamically influenced by the tumor microenvironment. NETs are engaged in tumorigenesis, formation, metastatic spread, and cancer-associated co-morbidities. NETs-based tumor biomarkers and therapeutic strategies warrant significant attention.

Pathological roles of NETs-platelet synergy in thrombotic diseases: From molecular mechanisms to therapeutic targeting

The formation of neutrophil extracellular traps (NETs) is a novel way for neutrophils to perform organismal protective functions essential for protecting the host against infections. Nevertheless, an increasing amount of data shows that uncontrolled or excessive formation of NETs in the body leads to inflammation and thrombosis. Many serious human diseases, such as sepsis, stroke, cancer, and autoimmune diseases, are associated with thrombosis, and inhibiting its formation is essential to prevent the development of many inflammatory and thrombotic diseases. With deeper research, it has been found that there is a complex interaction between NETs and platelets: platelets activate neutrophils to form NETs, while NET components enhance platelet aggregation and activation. This self-perpetuating vicious cycle between them mediates pathological processes such as inflammation, coagulation, and thrombosis. A deeper comprehension of the underlying molecular mechanisms between them promises to be a new target for thrombotic diseases. In this review, we concentrate on a summary of NET formation and its mechanisms of action. Providing a thorough summary of how neutrophils are activated by platelets to form NETs, how NETs cause platelet activation, and how this close interaction during inflammatory events affects the course of the disease, with the aim of providing fresh targets and ideas for thrombotic disease clinical prevention and therapy.

Interleukin-33 modulates NET formation via an autophagy-dependent manner to promote neutrophilic inflammation in cigarette smoke-exposure asthma

Cigarette smoke (CS) contributes to IL---33 release and neutrophil inflammation in asthma. Neutrophil extracellular traps (NETs) are essential for neutrophil function. However, the effect of IL--33 on neutrophils in cigarette smoke--exposure asthma remains unclear. We found that CS exposure led to lower lung function and a neutrophil--related phenotype in asthma, characterized by elevated neutrophil and Th17 cell counts. Granulocytic airway inflammation was ablated by sST2, which blocked excessive IL--33 release. Transcriptome analysis of mouse lungs revealed that IL--33 enhanced NET formation in HDM/CS-treated mice, which was further confirmed in our experimental asthma model and in asthma patients. NETs were associated with poor lung function and airway inflammation and directly facilitated monocyte--derived dendritic cell activation, further inducing Th2/Th17 polarization. Furthermore, we demonstrated a feedforward loop between NETs and neutrophil autophagy, both of which are dependent on reactive oxygen species (ROS) production and the mTOR-Hif-1α signaling pathway. Notably, IL--33 knockout suppressed autophagy and NETs, whereas the autophagy agonist rapamycin reversed the inhibition of NETs by sST2 in a mTOR--dependent manner. Our findings revealed that the IL--33/ST2 signaling pathway interacts with the neutrophil -autophagy--mTOR-Hif-1α-NET pathway, ultimately aggravating Th2/Th17-related inflammation. These insights could lead to potential therapeutic targets for mitigating exacerbations in asthmatic patients who are exposed to CS.

The inducible role of autophagy in cell death: emerging evidence and future perspectives

BACKGROUND

Autophagy is a lysosome-dependent degradation pathway for recycling intracellular materials and removing damaged organelles, and it is usually considered a prosurvival process in response to stress stimuli. However, increasing evidence suggests that autophagy can also drive cell death in a context-dependent manner. The bulk degradation of cell contents and the accumulation of autophagosomes are recognized as the mechanisms of cell death induced by autophagy alone. However, autophagy can also drive other forms of regulated cell death (RCD) whose mechanisms are not related to excessive autophagic vacuolization. Notably, few reviews address studies on the transformation from autophagy to RCD, and the underlying molecular mechanisms are still vague.

AIM OF REVIEW

This review aims to summarize the existing studies on autophagy-mediated RCD, to elucidate the mechanism by which autophagy initiates RCD, and to comprehensively understand the role of autophagy in determining cell fate.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review highlights the prodeath effect of autophagy, which is distinct from the generally perceived cytoprotective role, and its mechanisms are mainly associated with the selective degradation of proteins or organelles essential for cell survival and the direct involvement of the autophagy machinery in cell death. Additionally, this review highlights the need for better manipulation of autophagy activation or inhibition in different pathological contexts, depending on clinical purpose.

Jing-Yin-Gu-Biao formula protects mice from postinfluenza Staphylococcus aureus infection by ameliorating acute lung injury and improving hypercoagulable state via inhibiting NETosis

Background

Jing-Yin-Gu-Biao formula (JYGBF) is a Chinese medicine derived from Yupingfeng power, Huoxiangzhengqi powder and Yinqiao powder, and has been widely used to treat acute respiratory infections. This study aims to observe the effects of JYGBF against postinfluenza Staphylococcus aureus (S. aureus) infection.

Purpose and study design

A mouse model of secondary S. aureus infection following PR8 infection was established to evaluate the protective effects of JYGBF against postinfluenza Staphylococcus aureus (S. aureus) infection and related mechanisms were validated in vivo and in vitro.

Results

The administration of JYGBF significantly ameliorated acute lung injury (ALI) and inhibited overactivated inflammatory response (MIP-2, IL-6, etc.) in mice with postinfluenza S. aureus infection. Single cell RNA-sequencing (scRNA-seq) data indicated that neutrophils had the highest cytokine score in lungs and JYGBF inhibited neutrophil chemotaxis, reactive oxygen species (ROS) biosynthesis and ERK1/2 cascades in neutrophils. Meanwhile, JYGBF inhibited the formation of neutrophil extracellular traps (NETs) in lungs, which is characterized by the production of ROS, peptidyl arginine deiminase 4 (PAD4), citrullinated histone H3 (CitH3), myeloperoxidase (MPO), neutrophil elastase (NE), S100A8/A9 and MPO-CitH3 colocalization. Moreover, JYGBF decreased platelet counts and the expression of its activated markers (CD62P and αIIbβ3) accompanied by the drop of fibrinogen (FIB) and fibrin degradation product (FDP), accounting for alleviating hypercoagulable state. JYGBF inhibited ERK1/2 phosphorylation in neutrophils and in lungs of infected mice. Acacetin, a critical compound from JYGBF, inhibited NET formation via downregulating ERK/ROS axis.

Conclusions

These results indicated that JYGBF inhibited NET formation and overactivated inflammatory response by suppressing ERK/ROS axis in neutrophils, thereby mitigating ALI and improving the hypercoagulable state during postinfluenza S. aureus infection. JYGBF could be considered a potent therapeutic agent for the prevention and treatment of postinfluenza bacterial infection.

Exercise combined with metformin ameliorates diabetic kidney disease by increasing renal autophagy and reducing oxidative stress in rats with high-fat diet and streptozotocin induced diabetes

Diabetic kidney disease (DKD) is one of the common and serious complications of type 2 diabetes mellitus (T2DM). Metformin is commonly prescribed for the treatment of T2DM, while exercise is frequently recommended as adjunctive therapy. However, the therapeutic efficacy and molecular etiology of combined therapy with exercise and metformin in DKD remain to be elucidated. The present study therefore aimed to investigate the therapeutic effects and mechanisms underlying the combined effects of exercise and metformin on DKD. A rat model of T2DM was constructed by administering a high-fat diet and intraperitoneal injections of streptozotocin (30 mg/kg) for 6 weeks. The rats with T2DM exhibited reduced autophagic flux, increased oxidative stress, and morphological and structural lesions in the kidneys, compared to those of normal rats in the control group. The combination of exercise and metformin alleviated DKD, indicated by the elevation of renal autophagic flux, and a reduction in oxidative stress, renal fibrosis, and histopathological damage to the kidneys. Our findings suggested that exercise combined with metformin has a therapeutic role in DKD, and the study serves as a valuable reference for future research on the treatment of DKD.

Dysregulation of neutrophil in sepsis: recent insights and advances

Sepsis remains the leading cause of death in intensive care units. Despite newer antimicrobial and supportive therapies, specific treatments are still lacking. Neutrophils are pivotal components of the effector phase of the host immune defense against pathogens and play a crucial role in the control of infections under normal circumstances. In addition to its anti-infective effects, the dysregulation and overactivation of neutrophils may lead to severe inflammation or tissue damage and are potential mechanisms for poor prognosis in sepsis. This review focuses on recent advancements in the understanding of the functional status of neutrophils across various pathological stages of sepsis to explore the mechanisms by which neutrophils participate in sepsis progression and provide insights for the treatment of sepsis by targeting neutrophils.

Phellodendrine inhibits oxidative stress and promotes autophagy by regulating the AMPK/mTOR pathway in burn sepsis-induced intestinal injury

Intestinal injury is an important complication of burn sepsis with limited therapeutic choices. Phellodendrine is a promising compound for gastrointestinal inflammatory diseases and is extracted from the traditional Chinese medicine phellodendron bark. The study aimed to explore the role of phellodendrine against oxidative stress and autophagy in burn sepsis-induced intestinal injury. A mouse model of burn sepsis model was established by intraperitoneally injecting 10 mg/kg lipopolysaccharide (LPS) to mice burned by boiled water. Phellodendrine (30 mg/kg) was injected into mice in the drug group after scalding and before LPS injection. Hematoxylin and eosin staining was performed to observe histopathological changes in murine small intestines. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was performed to evaluate intestinal cell apoptosis. Immunofluorescence staining was performed to measure the expression and distribution of autophagy markers, light chain 3II (LC3II) and p62 in intestinal tissues. Oxidative stress indicators were detected using corresponding commercial kits. Protein levels of apoptotic markers, autophagy markers, and factors involved in adenosine monophosphate-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway in intestines were quantified by western blotting. Phellodendrine attenuated bun sepsis-induced intestinal pathological changes. Meanwhile, aggravated cell apoptosis, reduction of antioxidant enzymes, and downregulation of autophagy markers in intestinal tissues of burn sepsis group were all improved by phellodendrine. In addition, phellodendrine activated the phosphorylation (p) of AMPK and inhibited p-mTOR signaling in intestines of burn septic mice. In conclusion, phellodendrine suppresses oxidative stress and activates autophagy in burn sepsis-induced intestinal injury by activating AMPK and inhibiting mTOR signaling.

UHPLC-Q/Orbitrap HRMS combined with spectrum-effect relationship and network pharmacology to discovery the gastrointestinal motility-promoting material basis in Citri Sarcodactylis Fructus

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of gastrointestinal motility disorders (GMD) is increasing and is characterized by long-term recurrence. Citri Sarcodactylis Fructus (CSF), as a traditional Chinese medicine (TCM) known in "regulating qi and harmonizing the stomach", has therapeutic effects on GMD. However, the material basis of its efficacy is not clear.

AIM OF THE STUDY

The aim of this study was to evaluate the gastrointestinal motility-promoting activity of CSF extracts and to screen their active ingredients and to perform a preliminary validation.

METHODS

The chemical composition spectrum of different extracts of CSF were established by ultra high-performance liquid chromatography coupled with quadrupole orbitrap high-resolution mass spectrometry (UHPLC-Q/Orbitrap HRMS). The gastrointestinal motility-promoting activities of CSF were investigated by determining the intestinal propulsion rate, gastric emptying rate, acetylcholinesterase activity, and motilin content in L-arginine-induced GMD mice. Spectrum-effect relationship and network pharmacology analysis were used for the screening of potential active ingredients. A zebrafish gastrointestinal motility model traced with Nile Red was established to validate the active ingredients. Molecular docking prediction was used to explore the mechanism of action of the active ingredient. Finally, Western blotting and TUNEL staining were performed to validate the molecular docking predictions.

RESULTS

In total, 42 shared components were identified. The main active fraction of CSF to promote gastrointestinal motility was 70% ethanol elution fraction. Eleven potential active ingredients were screened by grey correlation analysis, orthogonal partial least squares analysis, and "active ingredient-target" network. Six compounds were confirmed as the pharmacodynamic substances of CSF by zebrafish gastrointestinal motility model, namely, quercetin, kaempferol, isorhamnetin, diosmetin, hesperetin, and 5,7,3'-trihydroxy-6,4',5'-trimethoxyflavone. Molecular docking predictions and Western blotting assays indicated that CSF may act on AKT and MMP9 targets to exert gastrointestinal motility-promoting activity.

CONCLUSION

This study provided a foundation for elucidating the gastrointestinal motility-promoting activity of CSF and its material basis by integrating spectrum-effect relationship and network pharmacology. It also provided a theoretical basis for quality control of CSF and a new idea for the discovery and validation of pharmacodynamic substances in TCM.

Geraniol modulates inflammatory and antioxidant pathways to mitigate intestinal ischemia-reperfusion injury in male rats

Intestinal ischemia-reperfusion injury (IIR/I) significantly increases morbidity and mortality. This study examines the therapeutic effects of geraniol (GNL), which is noted for its anti-inflammatory and antioxidant properties, on intestinal I/R injury in rats. Forty-nine male Wistar-Albino rats were divided into seven groups. After 30 min of ischemia and subsequent reperfusion for either 1 or 6 h, intestinal and hepatic tissues were analyzed. Biochemical assessments measured malondialdehyde (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), myeloperoxidase (MPO), and nitric oxide (NO) activities. Inflammatory and apoptotic markers were evaluated using qRT-PCR and ELISA, and apoptotic cell rates were determined by flow cytometry. GNL treatment significantly protected intestinal and hepatic tissues, enhancing antioxidant enzyme activity and normalizing MDA and NO activities. It demonstrated notable anti-inflammatory effects at 100 and 200 mg/kg doses, reducing TNF-α, IL-1β, and IL-6 levels while decreasing tissue MPO content. GNL also increased Bcl-2 levels and decreased Bax levels, indicating anti-apoptotic effects. Serum activities of ALT, AST, and creatine kinase were lower in GNL-treated rats, and flow cytometry showed a reduction in apoptotic cells. GNL effectively mitigated oxidative stress and histopathological damage from intestinal I/R injury by reducing pro-apoptotic markers and increasing anti-apoptotic markers, highlighting its protective effects.

Limosilactobacillus reuteri ZY15 Alleviates Intestinal Inflammation and Barrier Dysfunction via AKT/mTOR/HIF-1α/RORγt/IL-17 Signaling and the Gut Microbiota in ETEC K88-Challenged Mice

Limosilactobacillus reuteri, a recognized probiotic, improves intestinal health in animals, but the mechanism remains unclear. This study investigates the mechanisms by which L. reuteri ZY15, isolated from healthy pig feces, mitigates intestinal barrier damage and inflammation caused by oxidative stress in Enterotoxigenic Escherichia coli (ETEC) K88-challenged mice. The results indicated that L. reuteri ZY15 increased antioxidant capacity by reducing serum reactive oxygen species (ROS) and superoxide dismutase (SOD) levels. L. reuteri ZY15 enhanced the intestinal barrier by upregulating mucin 1, mucin 2, occludin, zonula occludens-1 (ZO-1), and claudin-1 expressions in protein and mRNA levels. It significantly alleviated intestinal inflammation by reducing the proinflammatory cytokines interleukin-1β (IL-1β), interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and interleukin-17 (IL-17) mRNA and protein levels. Notably, L. reuteri ZY15 suppressed intestinal inflammation by inhibiting AKT/mTOR/HIF-1α/RORγt/IL-17 pathway activation. Additionally, it significantly altered the structure of gut microorganisms by enriching Akkermansia and Clostridia_UCG.014, and thereby re-establishing colonization resistance and alleviating ETEC K88-induced intestinal barrier damage and inflammation in mice. Taken together, our findings reveal the protective mechanism of L. reuteri ZY15 in mice challenged with ETEC K88 by regulating AKT/mTOR/HIF-1α/RORγt/IL-17 signaling and microbial imbalance. Leveraging these properties, live L. reuteri ZY15 offers a promising alternative treatment for Escherichia coli-induced diarrhea in weaned piglets.

Fighting sepsis-induced liver damage with biosynthesized silver nanoparticles

Sepsis is a potentially fatal disease that arises from an infection and is characterized by an uncontrolled immune system reaction. Global healthcare systems bear a heavy financial burden from treating sepsis. This study aimed to provide information on the effective properties of silver nanoparticles derived from pomegranate peel extract (P-AgNP) against sepsis-induced hepatic injury. P-AgNPs were spherical with a diameter of ~19 nm. The animals were placed into four groups, each with seven rats. Group 1 functioned as the control group, receiving only saline for 7 days. Group 2 received only P-AgNPs at a dose of 20 mg/kg. To induce sepsis, groups 3 and 4 were given an intraperitoneal injection of 200 mg/mL cecal slurry. Sixty min later, group 4 was given 20 mg/kg of P-AgNPs daily for 7 days. The concentrations of reduced glutathione, nitric oxide, lipid peroxidation, and superoxide dismutase in liver homogenate were measured to determine the oxidative status. In addition, enzyme activities (alanine aminotransferase, aspartate amino transferase, and alkaline phosphatase) were measured. Furthermore, we investigated the histological changes, immunohistochemical expression of nuclear factor-κB, and mRNA levels of IL1β, IL-6, TNF-α, Bax, BCl2, and Casp-3. P-AgNPs functioned as regulators in a sepsis model, successfully controlling altered gene expression. Following treatment, P-AgNPs improved tion and oxidative state, indicating a role in sepsis management. Based on our findings, we conclude that P-AgNPs have antioxidant activity and may be useful in preventing sepsis-induced liver inflammation, oxidative damage, and apoptosis. RESEARCH HIGHLIGHTS: Pomegranate peel-derived silver nanoparticles (P-AgNPs) enhanced liver function and oxidative state in rats with sepsis-induced hepatic damage. P-AgNPs reduced oxidative stress and liver inflammation via regulating inflammatory and apoptotic gene expression. P-AgNPs enhanced liver enzyme activities, histological structure, and immunohistochemistry expression of nuclear factor-κB.

Nano Acacetin Mitigates Intestinal Mucosal Injury in Sepsis Rats by Protecting Mitochondrial Function and Regulating TRX1 to Inhibit the NLRP3 Pyroptosis Pathway

Background

Acacetin (AC) is a flavonoid compound with antiperoxidant, anti-inflammatory, and antiplasmodial activity. However, the solubility of AC is poor and nano acacetin (Nano AC) was synthesized. The intestinal mucosal barrier is impaired in sepsis rats, and the protective effects and mechanism of AC and Nano AC on the intestinal mucosal barrier are unclear.

Methods

Cecal ligation and perforation (CLP) was used to induce sepsis in rats, and lipopolysaccharide (LPS)-stimulated intestinal epithelial cells were used to observe the effects of AC and our synthesized Nano AC on the amelioration of intestinal mucosal damage. The molecular docking technique was used to predict the binding energy of AC to thioredoxin reductase 1 (TRX1) signaling pathway proteins. TRX1 inhibitor (PX-12) was employed to elucidate the protective signaling pathway of Nano AC in LPS-stimulated intestinal epithelial cells.

Results

Our synthesized Nano AC, with an average particle size of 17.18 ± 0.48 nm and an uptake rate of 95% in intestinal epithelial cells. The maximum binding capacity of AC to TRX1 was -6.82 kcal/mol, supporting the hypothesis that TRX1 is a potential target of AC. AC and Nano AC ameliorated the survival rate, intestinal mucosal damage score, pathological morphology, hepatic and renal function, and myocardial troponin levels, decreased serum levels of pyroptosis-related factors, upregulated TRX1, down-regulated NOD-like receptor protein 3 inflammasome (NLRP3), cysteinyl aspartate specific proteinase-11 (Caspase-11), Gasdermin D (GSDMD) in sepsis rats. They improved mitochondrial morphology and mitochondrial reactive oxygen species (ROS) levels, reduced pyroptosis levels, and upregulated TRX1, which adjusted NLRP3/ Caspase-11/ GSDMD signaling pathway in LPS-stimulated intestinal epithelial cells. Moreover, Nano AC was more effective.

Conclusion

AC and Nano-AC can inhibit the NLRP3/Caspase-11/GSDMD signaling pathway by upregulating TRX1 to ameliorate intestinal mucosal injury in sepsis rats, and the effect of Nano AC is more prominent.

Neutrophil Extracellular Trap Formation Model Induced by Monosodium Urate and Phorbol Myristate Acetate: Involvement in MAPK Signaling Pathways

Neutrophil extracellular traps (NETs) formation is a key process in inflammatory diseases like gout, but the underlying molecular mechanisms remain incompletely understood. This study aimed to establish a model to examine the formation of NETs induced by monosodium urate (MSU) and phorbol 12-myristate 13-acetate (PMA) and to elucidate their molecular pathways. Laser confocal microscopy was used to visualize NET formation, while flow cytometry was employed to detect reactive oxygen species (ROS) production. The microstructure of neutrophils was observed by transmission electron microscopy, and the expression of key proteins was determined by Western blotting. Additionally, the effect of various inhibitors targeting the MAPK signaling pathway on NET formation was evaluated. They include the Ras inhibitor Salirasib, Raf inhibitor Vemurafenib, ERK inhibitor PD98059, and p38 MAPK inhibitor SB203580, as well as NADPH oxidase inhibitor DPI and neutrophil elastase inhibitor Alvelestat. The results showed that MSU and PMA triggered significant NET formation, which was accompanied by increased ROS levels, lactate dehydrogenase release, dsDNA, and IL-8. Notably, selective MAPK pathway inhibitors and DPI and Alvelestat, except for SB203580, effectively down-regulated these indicators. These data indicated that the activation of a signaling pathway involving Ras-Raf-ERK, which is dependent on ROS, is crucial for the induction of NET formation by MSU and PMA. Given the involvement of NETs in multiple pathologies, our findings could potentially serve as molecular targets for the intervention and treatment of crystal-related diseases, especially for gout.

Screening study of hydroxytyrosol metabolites from in vitro fecal fermentation and their interaction with intestinal barrier repair receptor AhR

Olive oil polyphenol hydroxytyrosol (HT) significantly repairs intestinal barrier function, but its absorption in the stomach and small intestine is limited. The metabolites of unabsorbed HT that reach the colon are crucial, yet their effects on colonic microbiota and intestinal barrier repair remain unclear. This study utilized in vitro simulated digestion and colonic fecal fermentation to investigate HT's digestion and fermentation. Results indicated that 79.25% of HT potentially reached the colon intact. Further 16S rDNA, targeted, and untargeted metabolomics analyses showed that HT can be decomposed by colonic microbiota, producing aromatic hydrocarbon metabolites and regulating gut microbiota structure. It promotes the growth of gut microbiota, such as Bacteroides, Faecalibacterium, Klebsiella, and Lachnospira, which degrade HT. Additionally, HT's intervention conversely affected the production of tryptophan-derived metabolites and short-chain fatty acids (SCFAs). Subsequently, computer-simulated molecular docking technology was used to simulate the binding affinity between HT metabolites and derived metabolites and the intestinal barrier repair-related receptor aryl hydrocarbon receptor (AhR). Indole-3-acetic acid, indole-3-acetaldehyde, skatole, kynurenine, and homovanillic acid could tightly bind to the amino acid residues of the AhR receptor, with binding energies all ˂-6.0 kcal/mol, suggesting that these metabolites may enhance the intestinal barrier function through the AhR signaling pathway.

Comprehensive review of Hesperetin: Advancements in pharmacokinetics, pharmacological effects, and novel formulations

Hesperetin is a flavonoid compound naturally occurring in the peel of Citrus fruits from the Rutaceae family. Previous studies have demonstrated that hesperetin exhibits various pharmacological effects, such as anti-inflammatory, anti-tumor, antioxidative, anti-aging, and neuroprotective properties. In recent years, with the increasing prevalence of diseases and the rising awareness of traditional Chinese medicine, hesperetin has garnered growing attention for its wide-ranging pharmacological effects. To substantiate its health benefits and elucidate potential mechanisms, knowledge of pharmacokinetics is crucial. However, the limited solubility of hesperetin restricts its bioavailability, thereby diminishing its efficacy as a beneficial health agent. To enhance the bioavailability of hesperetin, various novel formulations have been developed, including nanoparticles, liposomes, and cyclodextrin inclusion complexes. This article reviews recent advances in the pharmacokinetics of hesperetin and methods to improve its bioavailability, as well as its pharmacological effects and mechanisms, aiming to provide a theoretical basis for clinical applications.

Pharmacodynamic and pharmacokinetic study of Shaoyao Gancao decoction for repairing intestinal barrier damage in ulcerative colitis

OBJECTIVE

To study the therapeutic effect and mechanism of Shaoyao Gancao Decoction (SGD) on ulcerative colitis (UC) mice based on the perspective of intestinal barrier, and this study provides a new consultation for the clinical application of SGD.

METHODS

The chemical composition of SGD was characterized by HPLC. The UC mouse model was constructed by 3 % dextran sodium sulfate (DSS), which were randomly divided into the model group (DSS), the positive drug group (5-ASA), the Shaoyao group (SYD), Gancao group (GCD), and the Shaoyao Gancao Decoction group (SGD) at low, medium, and high dosages, respectively. The effects of each drug treatment group on UC were evaluated by the rate of body weight loss, disease activity index (DAI), colon length, spleen index, histopathological evaluations, and the levels of serum inflammatory factors (IL-1β, IL-6, IL-10, IL-21, and TNF-α). The goblet cell was observed by Alcian blue/periodic acid-Schiff (AB/PAS) straining, ELISA was used to detect the content of LPS in serum, and Western blot was used to detect the changes in the expression of tight junction proteins ZO-1, occludin, and the pathway proteins TLR4 and NF-κBp65 in the colonic tissues, to explore the protective effect of SGD on the intestinal barrier of UC mice. The vivo absorption process of the main active ingredients in the SG, SY and GC groups was determined by LC-MS.

RESULTS

The contents of albiflorin, paeoniflorin, liquiritin apioside, liquiritin and glycyrrhetinic acid were 6.1227 mg/g, 20.8993 mg/g, 4.0054 mg/g, 3.6140 mg/g and 8.2515 mg/g, respectively. Compared with DSS group, SGD reduced weight loss(P<0.01) and DAI scores(P<0.05), prevented colon shortening(P<0.01), and ameliorated histopathological damage of the colon in UC mice(P<0.01). SGD also protected the intestinal barrier to alleviate UC by significantly reducing serum LPS and inflammatory factor levels, altering the number of goblet cells, promoting tight junction proteins (ZO-1 and occludin) and decreasing the expression of TLR4 and NF-κB in colonic tissues. Pharmacokinetic results showed that there was no significant difference in Cmax, AUC0-t (μg/L.h) and Tmax of albiflorin and paeoniflorin between the SY and SG groups, the Tmax was within 1 h; the AUC0-t (μg/L.h) of liquiritin and glycyrrhizic acid were about 1.6 and 1.9 times higher in the SG group compared to the GC group, respectively. The Cmax, Tmax and AUC0-t (μg/L.h) of glycyrrhizinic acid were significantly reduced to 0.73, 0.68 and 0.68 times of that of the GC group.

CONCLUSION

SGD may have a therapeutic effect on DSS-induced UC mice by repairing the damaged intestinal barrier through the TLR4/NF-κB pathway. The combination of Shaoyao and Gancao increased the absorption of liquiritin and glycyrrhizic acid in vivo. The combination of Shaoyao and Gancao could promote the absorption of Gancao, and that the pairing of the two herbs could have a synergistic effect.

Neutrophils: a key component in ECMO-related acute organ injury

Extracorporeal membrane oxygenation (ECMO), as an extracorporeal life support technique, can save the lives of reversible critically ill patients when conventional treatments fail. However, ECMO-related acute organ injury is a common complication that increases the risk of death in critically ill patients, including acute kidney injury, acute brain injury, acute lung injury, and so on. In ECMO supported patients, an increasing number of studies have shown that activation of the inflammatory response plays an important role in the development of acute organ injury. Cross-cascade activation of the complement system, the contact system, and the coagulation system, as well as the mechanical forces of the circuitry are very important pathophysiological mechanisms, likely leading to neutrophil activation and the production of neutrophil extracellular traps (NETs). NETs may have the potential to cause organ damage, generating interest in their study as potential therapeutic targets for ECMO-related acute organ injury. Therefore, this article comprehensively summarized the mechanism of neutrophils activation and NETs formation following ECMO treatment and their actions on acute organ injury.

Nets in fibrosis: Bridging innate immunity and tissue remodeling

Fibrosis, a complex pathological process characterized by excessive deposition of extracellular matrix components, leads to tissue scarring and dysfunction. Emerging evidence suggests that neutrophil extracellular traps (NETs), composed of DNA, histones, and antimicrobial proteins, significantly contribute to fibrotic diseases pathogenesis. This review summarizes the process of NETs production, molecular mechanisms, and related diseases, and outlines the cellular and molecular mechanisms associated with fibrosis. Subsequently, this review comprehensively summarizes the current understanding of the intricate interplay between NETs and fibrosis across various organs, including the lung, liver, kidney, skin, and heart. The mechanisms by which NETs contribute to fibrogenesis, including their ability to promote inflammation, induce epithelial-mesenchymal transition (EMT), activate fibroblasts, deposit extracellular matrix (ECM) components, and trigger TLR4 signaling were explored. This review aimed to provide insights into the complex relationship between NETs and fibrosis via a comprehensive analysis of existing reports, offering novel perspectives for future research and therapeutic interventions.

Hesperidin Alleviated Intestinal Barrier Injury, Mitochondrial Dysfunction, and Disorder of Endoplasmic Reticulum Mitochondria Contact Sites under Oxidative Stress

As primary flavonoids extracted from citrus fruits, hesperidin has been attracting attention widely for its capacity to act as antioxidants that are able to scavenge free radicals and reactive oxygen species (ROS). Many factors have made oxidative stress a risk factor for the occurrence of intestinal barrier injury, which is a serious health threat to human beings. However, little data are available regarding the underlying mechanism of hesperidin alleviating intestinal injury under oxidative stress. Recently, endoplasmic reticulum (ER) mitochondria contact sites (ERMCSs) have aroused increasing concerns among scholars, which participate in mitochondrial dynamics and Ca2+ transport. In our experiment, 24 piglets were randomly divided into 4 groups. Piglets in the diquat group and hesperidin + diquat group received an intraperitoneal injection of diquat (10 mg/kg), while piglets in the hesperidin group and hesperidin + diquat group received hesperidin (300 mg/kg) with feed. The results indicated that hesperidin alleviated growth restriction and intestinal barrier injury in piglets compared with the diquat group. Hesperidin ameliorated oxidative stress and restored antioxidant capacity under diquat exposure. The mitochondrial dysfunction was markedly alleviated via hesperidin versus diquat group. Meanwhile, hesperidin alleviated ER stress and downregulated the PERK pathway. Furthermore, hesperidin prevented the disorder of ERMCSs by downregulating the level of ERMCS proteins, decreasing the percentage of mitochondria with ERMCSs/total mitochondria and the ratio of ERMCSs length/mitochondrial perimeter. These results suggested hesperidin could alleviate ERMCS disorder and prevent mitochondrial dysfunction, which subsequently decreased ROS production and alleviated intestinal barrier injury of piglets under oxidative stress.

Geranylgeranylacetone mitigates sepsis-associated intestinal injury through CHIP-dependent anti-inflammation and anti-oxidative effect

Geranylgeranylacetone (GGA), an isoprenoid compound widely utilized as an antiulcer agent in Asia, confers protection against ischemia, anoxia, and oxidative stress by rapidly enhancing the expression of HSP70. Nevertheless, the impact of GGA on sepsis-associated intestinal injury remains unexplored. Thus, this study is crafted to elucidate the protective efficacy and underlying mechanisms of GGA against septic intestinal damage. Our findings revealed that GGA significantly extended the survival duration of septic mice, and mitigated lipopolysaccharide (LPS)-induced alterations in intestinal permeability and tissue damage. Furthermore, GGA effectively suppressed LPS-induced cytokine release, attenuated levels of reactive oxygen species (ROS) and malondialdehyde, and bolstered antioxidant-related parameters within the intestinal tissue of LPS-stimulated mice. Mechanistically, GGA significantly increased HSP70 expression and promoted E3 ubiquitin ligase CHIP to play the role in ubiquitination and degradation of karyopherin-α2 (KPNA2), resulting in inhibition of nuclear translocation of NF-κB and reduced NOX1, NOX2 and NOX4 expression. The inhibitory action of GGA on cytokine release and ROS generation was abolished by CHIP knockdown in IEC-6 cells treated with LPS. Simultaneously, the downregulation of CHIP reversed the suppressive role of GGA in the LPS-induced NF-κB activation and the expression of NOX1, NOX2 and NOX4 in IEC-6 cells. The effects of GGA on mitigating intestinal damage, inflammation and oxidative stress caused by LPS were eliminated in CHIP knockout mice. Our results demonstrate that the protective effect of GGA against LPS-caused intestinal injury of mice is dependent on CHIP activation, which promotes KPNA2 degradation and restrains translocation of NF-κB into nucleus, leading to suppressing LPS-induced inflammatory response and oxidative stress.

Fucoxanthin alleviates lipopolysaccharide-induced intestinal barrier injury in mice

The aim of this study was to evaluate the preventive role and underlying mechanisms of fucoxanthin (Fx) on lipopolysaccharide (LPS)-induced intestinal barrier injury in mice. Our results demonstrated that the oral administration of Fx (50 and 200 mg per kg body weight per day) for consecutive 7 days significantly alleviated the severity of LPS-induced intestinal barrier injury in mice, as evidenced by attenuating body weight loss, improving intestinal permeability, and ameliorating intestinal morphological damage such as reduction in the ratio of the villus length to the crypt depth (V/C), intestinal epithelium distortion, goblet cell depletion, and low mucin 2 (MUC2) expression. Fx also significantly mitigated LPS-induced excessive apoptosis of intestinal epithelial cells (IECs) and curbed the decrease of tight junction proteins including claudin-1, occludin, and zonula occludens-1 in the ileum and colon. Additionally, Fx effectively alleviated LPS-induced extensive infiltration of macrophages and neutrophils into the intestinal mucosa, the overproduction of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin 1beta (IL-1β) and IL-6, and gasdermin D (GSDMD)-mediated pyroptosis of IECs. The underlying mechanisms might be associated with inhibiting the activation of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs) and nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome signaling pathways. Moreover, Fx also notably restrained intestinal reactive oxygen species (ROS), malondialdehyde and protein carbonylation levels in LPS-treated mice, and it might be mediated by activating the nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway. Overall, these findings indicated that Fx might be developed as a potential effective dietary supplement to prevent intestinal barrier injury.

Focus on the cGAS-STING Signaling Pathway in Sepsis and Its Inflammatory Regulatory Effects

Sepsis is a severe systemic inflammatory response commonly occurring in infectious diseases, caused by infection with virulent pathogens. In the pathogenesis of sepsis, the cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase-stimulator of interferon genes (cGAS-STING) signaling pathway serves a crucial role as a fundamental immunoregulatory mechanism. This signaling pathway activates STING upon recognizing intracellular DNA damage and pathogen-derived DNA, subsequently inducing the production of numerous inflammatory mediators, including interferon and inflammatory cytokines, which in turn trigger an inflammatory response. The aim of this paper is to explore the activation mechanism of the cGAS-STING signaling pathway in sepsis and its impact on inflammatory regulation. By delving into the mechanism of action of the cGAS-STING signaling pathway in sepsis, we aim to identify new therapeutic strategies for the treatment and prevention of sepsis.

Magnesium hydride attenuates intestinal barrier injury during hemorrhage shock by regulating neutrophil extracellular trap formation via the ROS/MAPK/PAD4 pathway

Magnesium hydride (MgH2) is a hydrogen storage material that is known for its high capacity and safety and is capable of releasing hydrogen in a controlled manner when administered orally. This release of hydrogen has been associated with a range of biological effects, including anti-inflammatory properties, antioxidant activity, and protection of the intestinal barrier. Previous research has shown that neutrophil extracellular traps (NETs) play a role in the dysfunction of the intestinal barrier in conditions such as sepsis and critical illnesses. However, it remains unclear as to whether MgH2 can protect the intestinal barrier by inhibiting NET formation, and the underlying mechanisms have yet to be elucidated. A rat model of hemorrhagic shock was created, and pretreatment or posttreatment procedures with MgH2 were performed. After 24 h, samples from the small intestine and blood were collected for analysis. In vitro, human neutrophils were incubated with either phorbol-12-myristate-13-acetate (PMA) or MgH2. Reactive oxygen species generation and the expression of key proteins were assessed. The results demonstrated that MgH2 administration led to a decrease in inflammatory cytokines in the serum and mitigated distant organ dysfunction in rats with HS. Furthermore, MgH2 treatment reversed histopathological damage in the intestines, improved intestinal permeability, and enhanced the expression of tight junction proteins (TJPs) during HS. Additionally, MgH2 treatment was found to suppress NET formation in the intestines. In vitro pretreatment with MgH2 alleviated intestinal monolayer barrier disruption that was induced by NETs. Mechanistically, MgH2 pretreatment reduced ROS production and NET formation, inhibited the activation of ERK and p38, and suppressed the expression of the PAD4 protein. These findings indicated that MgH2 may inhibit NET formation in a ROS/MAPK/PAD4-dependent manner, which reduces NET-related intestinal barrier damage, thus offering a novel protective role in preventing intestinal barrier dysfunction during HS.

Advances in molecular agents targeting toll-like receptor 4 signaling pathways for potential treatment of sepsis

Sepsis is a systemic inflammatory response syndrome caused by an infection. Toll-like receptor 4 (TLR4) is activated by endogenous molecules released by injured or necrotic tissues. Additionally, TLR4 is remarkably sensitive to infection of various bacteria and can rapidly stimulate host defense responses. The TLR4 signaling pathway plays an important role in sepsis by activating the inflammatory response. Accordingly, as part of efforts to improve the inflammatory response and survival rate of patients with sepsis, several drugs have been developed to regulate the inflammatory signaling pathways mediated by TLR4. Inhibition of TLR4 signal transduction can be directed toward either TLR4 directly or other proteins in the TLR4 signaling pathway. Here, we review the advances in the development of small-molecule agents and peptides targeting regulation of the TLR4 signaling pathway, which are characterized according to their structural characteristics as polyphenols, terpenoids, steroids, antibiotics, anthraquinones, inorganic compounds, and others. Therefore, regulating the expression of the TLR4 signaling pathway and modulating its effects has broad prospects as a target for the treatment of lung, liver, kidneys, and other important organs injury in sepsis.

Malvidin alleviates LPS-induced septic intestinal injury through the nuclear factor erythroid 2-related factor 2/reactive oxygen species/NLRP3 inflammasome pathway

Emerging evidence suggests that the gastrointestinal tract plays a crucial role in the pathophysiology of sepsis, a leading cause of mortality among patients admitted to the intensive care unit (ICU). Malvidin, belonging to the flavonoid family of compounds, exhibits a range of capabilities including anti-inflammatory and antioxidant properties. Studies have demonstrated that Malvidin exhibits a dose-dependent effect in mitigating sepsis-induced intestinal injury. The advantageous impact of Malvidin in safeguarding against sepsis-induced intestinal injury is associated with its capacity to counteract oxidative stress, inhibit cellular apoptosis, diminish the secretion of pro-inflammatory cytokines, and regulate the synthesis of inflammasomes. The findings indicate that Malvidin, a natural compound, exhibits protective effects on the gut by activating the nuclear factor erythroid 2-related factor 2/reactive oxygen species/NLRP3 inflammasome pathway. These results have significant implications for potential clinical applications and offer valuable insights into the treatment of sepsis-induced intestinal injury.

Mixed micelles loaded with hesperidin protect against acetaminophen induced acute liver injury by inhibiting the mtDNA-cGAS-STING pathway

Excessive acetaminophen (APAP) is the main cause of drug-induced acute liver failure, and the pathogenesis has not been elucidated and there is a lack of effective drugs. Hesperidin (Hes), a rich flavanone in citrus peel with excellent biological activities, is a potential agent for treatment liver injury. Due to poor water solubility of Hes, this study prepared mixed micelles using polyvinyl pyrrolidone (PVP K17) and poloxamer 188, and encapsulated Hes (Hes-MMs). The results showed that Hes-MMs exhibited a uniform spherical shape with a particle size of 66.80 ± 0.83 nm, and Hes-MMs significantly improved the dispersibility, antioxidant activity, and cellular uptake of Hes. In vitro results showed that Hes-MMs protected the proliferation inhibition of HepG2 cells induced by APAP, inhibited the production of reactive oxygen species (ROS) and the damage of mitochondrial membrane potential (MMP) induced by APAP. Furthermore, Hes-MMs exerted liver protective effects by inhibiting APAP induced mtDNA release and activating the cGAS-STING pathway. In vivo results demonstrated that Hes-MMs showed protective and therapeutic effects on APAP induced liver injury, and their mechanisms were related to the mtDNA-cGAS-STING signaling pathway. In summary, our study demonstrated that the mtDNA-cGAS-STING pathway was involved in APAP induced acute liver injury, and Hes-MMs might be a potential therapeutic agent for treating APAP induced acute liver injury.

Neutrophil extracellular traps regulating tumorimmunity in hepatocellular carcinoma

As a component of the innate immune system, there is emerging evidence to suggest that neutrophils may play a critical role in the initiation and progression of hepatocellular carcinoma (HCC). Neutrophil extracellular traps (NETs) are web-like chromatin structures that protrude from the membranes during neutrophil activation. Recent research has shown that NETs, which are at the forefront of the renewed interest in neutrophil studies, are increasingly intertwined with HCC. By exploring the mechanisms of NETs in HCC, we aim to improve our understanding of the role of NETs and gain deeper insights into neutrophil biology. Therefore, this article provides a summary of key findings and discusses the emerging field of NETs in HCC.

Neutrophil extracellular traps drive intestinal microvascular endothelial ferroptosis by impairing Fundc1-dependent mitophagy

Microvascular endothelial damage caused by intestinal ischemia‒reperfusion (II/R) is a primary catalyst for microcirculation dysfunction and enterogenous infection. Previous studies have mainly focused on how neutrophil extracellular traps (NETs) and ferroptosis cause intestinal epithelial injury, and little attention has been given to how NETs, mainly from circulatory neutrophils, affect intestinal endothelial cells during II/R. This study aimed to unravel the mechanisms through which NETs cause intestinal microvascular dysfunction. We first detected heightened local NET infiltration around the intestinal microvasculature, accompanied by increased endothelial cell ferroptosis, resulting in microcirculation dysfunction in both human and animal II/R models. However, the administration of the ferroptosis inhibitor ferrostatin-1 or the inhibition of NETs via neutrophil-specific peptidylarginine deiminase 4 (Pad4) deficiency led to positive outcomes, with reduced intestinal endothelial ferroptosis and microvascular function recovery. Moreover, RNA-seq analysis revealed a significant enrichment of mitophagy- and ferroptosis-related signaling pathways in HUVECs incubated with NETs. Mechanistically, elevated NET formation induced Fundc1 phosphorylation at Tyr18 in intestinal endothelial cells, which led to mitophagy inhibition, mitochondrial quality control imbalance, and excessive mitochondrial ROS generation and lipid peroxidation, resulting in endothelial ferroptosis and microvascular dysfunction. Nevertheless, using the mitophagy activator urolithin A or AAV-Fundc1 transfection could reverse this process and ameliorate microvascular damage. We first demonstrate that increased NETosis could result in intestinal microcirculatory dysfunction and conclude that suppressed NET formation can mitigate intestinal endothelial ferroptosis by improving Fundc1-dependent mitophagy. Targeting NETs could be a promising approach for treating II/R-induced intestinal microcirculatory dysfunction.

Role and Therapeutic Targeting Strategies of Neutrophil Extracellular Traps in Inflammation

Neutrophil extracellular traps (NETs) are large DNA reticular structures secreted by neutrophils and decorated with histones and antimicrobial proteins. As a key mechanism for neutrophils to resist microbial invasion, NETs play an important role in the killing of microorganisms (bacteria, fungi, and viruses). Although NETs are mostly known for mediating microbial killing, increasing evidence suggests that excessive NETs induced by stimulation of physical and chemical components, microorganisms, and pathological factors can exacerbate inflammation and organ damage. This review summarizes the induction and role of NETs in inflammation and focuses on the strategies of inhibiting NETosis and the mechanisms involved in pathogen evasion of NETs. Furthermore, herbal medicine inhibitors and nanodelivery strategies improve the efficiency of inhibition of excessive levels of NETs.