Naringin Decreases TNF-α and HMGB1 Release from LPS-Stimulated Macrophages and Improves Survival in a CLP-Induced Sepsis Mice

Significance of detecting cardiac troponin I and creatine kinase MB in critically Ill children without primary cardiac illness

Objective

To investigate the incidence of myocardial injury in children with critically ill children without primary cardiac disease and the association between elevated cardiac troponin I (cTnl) and creatine kinase MB (CK-MB) concentrations and disease progression and prognosis to guide early treatment.

Methods

The serum cTnI and CK-MB concentrations of 292 children with critically ill children without primary cardiac disease in Yantai Yuhuangding Hospital between January 2021 and January 2024 were retrospectively analyzed within 24 h after entering the Pediatric Intensive Care Unit (PICU). The children were divided into normal and abnormal groups according to the myocardial marker results. The abnormal group was further divided into the cTnI-elevated, CK-MB-elevated, single-elevated (cTnI- or CK-MB-elevated) and double-elevated (cTnI- and CK-MB-elevated) groups. The differences in the clinical indicators and their relationships with prognosis for the groups were compared.

Results

The incidence of myocardial injury among the critically ill children without primary cardiac disease was 55.1%. The incidence of myocardial injury in children with infectious diarrhea combined with moderate and severe dehydration reached 85.19%. The pediatric critical illness score; frequency of use of vasoactive drugs; hypotension, shock, heart failure, respiratory failure, and multiple organ dysfunction syndrome; and mortality indexes differed significantly for the normal and abnormal myocardial marker groups (P < 0.05). The single-elevated and normal groups only showed a difference in mortality (P < 0.017). The cTnI and CK-MB concentrations were negatively correlated with prognosis (P < 0.01).

Conclusion

Myocardial injury, as evidenced by elevated cardiac biomarkers, is common in critically ill children without primary cardiac illness. cTnI and CK-MB are associated with outcomes. Shock, heart failure, and multiple organ dysfunction syndromes are independently associated with simultaneous elevations of CK-MB and cTnI concentrations. Further prospective studies are needed to elucidate the clinical utility of these biomarkers.

Naringin dihydrochalcone alleviates sepsis-induced acute lung injury via improving gut microbial homeostasis and activating GPR18 receptor

Acute lung injury (ALI) is a life-threatening disease characterized by severe lung inflammation and intestinal microbiota disorder. The GPR18 receptor has been demonstrated to be a potential therapeutic target against ALI. Extracting Naringin dihydrochalcone (NDC) from the life-sustaining orange peel is known for its diverse anti-inflammatory properties, yet the specific action target remains uncertain. In the present study, we identified NDC as a potential agonist of the GPR18 receptor using virtual screening and investigated the pharmacological effects of NDC on sepsis-induced acute lung injury in rats and explored underlying mechanisms. In in vivo experiments, CLP-induced ALI model was established by cecum puncture and treated with NDC gavage one hour prior to drug administration, lung histopathology and inflammatory cytokines were evaluated, and feces were subjected to 16s rRNA sequencing and untargeted metabolomics analysis. In in vitro experiments, the anti-inflammatory properties were exerted by evaluating NDC targeting the GPR18 receptor to inhibit lipopolysaccharide (LPS)-induced secretion of TNF-α, IL-6, IL-1β and activation of inflammatory signaling pathways in MH-S cells. Our findings showed that NDC significantly ameliorated lung damage and pro-inflammatory cytokine levels (TNF-α, IL-6, IL-1β) in both cells and lung tissues via inhibiting the activation of STAT3, NF-κB, and NLRP3 inflammatory signaling pathways through GRP18 receptor activation. In addition, NDC can also partly reverse the imbalance of gut microbiota composition caused by CLP via increasing the proportion of Firmicutes/Bacteroidetes and Lactobacillus and decreasing the relative abundance of Proteobacteria. Meanwhile, the fecal metabolites in the NDC treatment group also significantly were changed, including decreased secretion of Phenylalanin, Glycine, and bile secretion, and increased secretion of Lysine. In conclusion, these findings suggest that NDC can alleviate sepsis-induced ALI via improving gut microbial homeostasis and metabolism and mitigate inflammation via activating GPR18 receptor. In conclusion, the results indicate that NDC, derived from the typical orange peel of food, could significantly contribute to development by enhancing intestinal microbial balance and metabolic processes, and reducing inflammation by activating the GPR18 receptor, thus mitigating sepsis-induced ALI and expanding the range of functional foods.

Natural products act as game-changer potentially in treatment and management of sepsis-mediated inflammation: A clinical perspective

BACKGROUND

Sepsis, a life-threatening condition resulting from uncontrolled host responses to infection, poses a global health challenge with limited therapeutic options. Due to high heterogeneity, sepsis lacks specific therapeutic drugs. Additionally, there remains a significant gap in the clinical management of sepsis regarding personalized and precise medicine.

PURPOSE

This review critically examines the scientific landscape surrounding natural products in sepsis and sepsis-mediated inflammation, highlighting their clinical potential.

METHODS

Following the PRISMA guidelines, we retrieved articles from PubMed to explore potential natural products with therapeutic effects in sepsis-mediated inflammation.

RESULTS

434 relevant in vitro and in vivo studies were identified and screened. Ultimately, 55 studies were obtained as the supporting resources for the present review. We divided the 55 natural products into three categories: those influencing the synthesis of inflammatory factors, those affecting surface receptors and modulatory factors, and those influencing signaling pathways and the inflammatory cascade.

CONCLUSION

Natural products' potential as game-changers in sepsis-mediated inflammation management lies in their ability to modulate hallmarks in sepsis, including inflammation, immunity, and coagulopathy, which provides new therapeutic avenues that are readily accessible and capable of undergoing rapid clinical validation and deployment, offering a gift from nature to humanity. Innovative techniques like bioinformatics, metabolomics, and systems biology offer promising solutions to overcome these obstacles and facilitate the development of natural product-based therapeutics, holding promise for personalized and precise sepsis management and improving patient outcomes. However, standardization, bioavailability, and safety challenges arise during experimental validation and clinical trials of natural products.

Naringin: A flavanone with a multifaceted target against sepsis-associated organ injuries

BACKGROUND

Sepsis causes multiple organ dysfunctions and raises mortality and morbidity rates through a dysregulated host response to infection. Despite the growing research interest over the last few years, no satisfactory treatment exists. Naringin, a naturally occurring bioflavonoid with vast therapeutic potential in citrus fruits and Chinese herbs, has received much attention for treating sepsis-associated multiple organ dysfunctions.

PURPOSE

The review describes preclinical evidence of naringin from 2011 to 2024, particularly emphasizing the mechanism of action mediated by naringin against sepsis-associated specific injuries. The combination therapy, safety profile, drug interactions, recent advancements in formulation, and future perspectives of naringin are also discussed.

METHODS

In vivo and in vitro studies focusing on the potential role of naringin and its mechanism of action against sepsis-associated organ injuries were identified and summarised in the present manuscript, which includes contributions from 2011 to 2024. All the articles were extracted from the Medline database using PubMed, Science Direct, and Web of Science with relevant keywords.

RESULTS

Research findings revealed that naringin modulates many signaling cascades, such as Rho/ROCK and PPAR/STAT1, PIP3/AKT and KEAP1/Nrf2, and IkB/NF-kB and MAPK/Nrf2/HO-1, to potentially protect against sepsis-induced intestinal, cardiac, and lung injury, respectively. Furthermore, naringin treatment exhibits anti-inflammatory, anti-apoptotic, and antioxidant action against sepsis harm, highlighting naringin's promising effects in septic settings. Naringin could be employed as a treatment against sepsis, based on studies on combination therapy, synergistic effects, and toxicological investigation that show no reported severe side effects.

CONCLUSION

Naringin might be a promising therapeutic approach for preventing sepsis-induced multiple organ failure. Naringin should be used alongside other therapeutic therapies with caution despite its great therapeutic potential and lower toxicity. Nonetheless, clinical studies are required to comprehend the therapeutic benefits of naringin against sepsis.

Nose to brain delivery of naringin-loaded chitosan nanoparticles for potential use in oxaliplatin-induced chemobrain in rats: impact on oxidative stress, cGAS/STING and HMGB1/RAGE/TLR2/MYD88 inflammatory axes

OBJECTIVES

Oxaliplatin induces chemobrain in cancer patients/survivors. Nutraceutical naringin has antioxidant and anti-inflammatory properties with low oral bioavailability. Our aim was to formulate naringin in chitosan nanoparticles for nose to brain delivery and assess its neuroprotective effect against oxaliplatin-induced chemobrain in rats.

METHODS

Naringin chitosan nanoparticles were prepared by ionic gelation. Rats were administered oral naringin (80 mg/kg), intranasal naringin (0.3 mg/kg) or intranasal naringin-loaded chitosan nanoparticles (0.3 mg/kg). Naringin's neuroprotective efficacy was assessed based on behavioral tests, histopathology, and measuring oxidative stress and inflammatory markers.

RESULTS

Selected nanoparticles formulation showed drug loading of 5%, size of 150 nm and were cationic. Intranasal naringin administration enhanced memory function, inhibited hippocampal acetylcholinesterase activity, and corrected oxaliplatin-induced histological changes. Moreover, it reduced malondialdehyde and elevated reduced glutathione hippocampal levels. Furthermore, it decreased levels of inflammatory markers: NF-kB and TNF-α by 1.25-fold. Upstream to this inflammatory status, intranasal naringin downregulated the hippocampal protein levels of two pathways: cGAS/STING and HMGB1/RAGE/TLR2/MYD88.

CONCLUSION

Intranasal naringin-loaded chitosan nanoparticles showed superior amelioration of oxaliplatin-induced chemobrain in rats at a dose 267-fold lower to that administered orally. The potential involvement of cGAS/STING and HMGB1/RAGE/TLR2/MYD88 pathways in the mechanistic process of either oxaliplatin-induced chemobrain or naringin-mediated neuroprotection was evidenced.

The effects of flavonoids in experimental sepsis: A systematic review and meta-analysis

Sepsis is a host's dysregulated immune response to an infection associated with systemic inflammation and excessive oxidative stress, which can cause multiple organ failure and death. The literature suggests that flavonoids, a broad class of secondary plant metabolites, have numerous biological activities which can be valuable in the treatment of sepsis. This study aimed to review the effects of flavonoids on experimental sepsis, focusing mainly on survival rate, and also summarizing information on its mechanisms of action. We searched in the main databases up to November 2022 using relevant keywords, and data were extracted and analyzed qualitatively and quantitatively. Thirty-two articles met the study criteria for review and 29 for meta-analysis. Overall, 30 different flavonoids were used in the studies. The flavonoids were able to strongly inhibit inflammatory response by reducing the levels of important pro-inflammatory mediators, for example, tumor necrosis factor-alpha and interleukin-1β, oxidative stress, and showed antibacterial and anti-apoptotic actions. The meta-analysis found an increase of 50% in survival rate of the animals treated with flavonoids. They appear to act as multi-target drugs and may be an excellent therapeutic alternative to reduce a number of the complications caused by sepsis, and consequently, to improve survival rate.

Huoxiang Zhengqi Oral Liquid Attenuates LPS-Induced Acute Lung Injury by Modulating Short-Chain Fatty Acid Levels and TLR4/NF-κB p65 Pathway

Huoxiang Zhengqi Oral Liquid (HZOL) is a classic Chinese patent medicine used in China for more than 1,000 years in treating gastrointestinal and respiratory diseases. Clinically applied HZOL in early respiratory disease stages can reduce the proportion of lung infection patients that progress to severe acute lung injury (ALI). However, few pharmacological studies evaluated its level of protection against ALI. We explored mechanisms of HZOL against ALI by employing network pharmacology, molecular docking, and rat experiments. Firstly, network pharmacology prediction and published biological evaluation of active ingredients of HZOL suggested that HZOL exerted the protective effect in treating ALI mainly in the areas of regulation of cell adhesion, immune response, and inflammatory response and closely related to the NF-κB pathway. Secondly, molecular docking results demonstrated that imperatorin and isoimperatorin combined well with targets in the NF-κB pathway. Finally, ALI rats induced by lipopolysaccharides (LPS) were used to validate prediction after pretreatment with HZOL for 2 weeks. Results confirmed that lung and colon injury occurred in ALI rats. Furthermore, HZOL exerts anti-inflammatory effects on LPS-induced ALI and gut injury by repairing lung and colon pathology, reducing and alleviating pulmonary edema, inhibiting abnormal enhancement of thymus and spleen index, modulating hematologic indices, and increasing levels of total short-chain fatty acids (SCFAs) in the cecum. Additionally, abnormal accumulation of inflammatory cytokines IL-6, IL-1β, TNF-α, and IFN-γ in serum and bronchoalveolar lavage fluid was significantly reduced after pretreating with HZOL. Furthermore, HZOL downregulated the expression of TLR4, CD14, and MyD88 and phosphorylation of NF-κB p65 in lung tissue. Altogether, HZOL was found to exert an anti-inflammatory effect regulation by increasing levels of SCFAs, inhibiting the accumulation of inflammatory cytokines, and attenuating the activation of the TLR4/NF-κB p65 pathway. Our study provided experimental evidences for the application of HZOL in preventing and treating ALI.

Plants' bioactive secondary metabolites in the management of sepsis: Recent findings on their mechanism of action

Sepsis is a severe inflammatory response to systemic infection and is a threatening cause of death in intensive care units. In recent years, a number of studies have been conducted on the protective effect of natural products against sepsis-induced organ injury. However, a comprehensive review of these studies indicating the mechanisms of action of the bioactive compounds is still lacking. In this context, this review aimed to provide an updated analysis of the mechanism of action of plants' secondary metabolites in the management of sepsis. Scopus, Science Direct, Google Scholar, and PubMed were searched from inception to July 2022. A variety of secondary metabolites were found to be effective in sepsis management including allicin, aloin, cepharanthine, chrysin, curcumin, cyanidin, gallic acid, gingerol, ginsenoside, glycyrrhizin, hesperidin, kaempferol, narciclasine, naringenin, naringin, piperine, quercetin, resveratrol, rosmarinic acid, shogaol, silymarin, sulforaphane, thymoquinone, umbelliferone, and zingerone. The protective effects exerted by these compounds can be ascribed to their antioxidant properties as well as induction of endogenous antioxidant mechanisms, and also via the downregulation of inflammatory response and reduction of biochemical and inflammatory markers of sepsis. These findings suggest that these secondary metabolites could be of potential therapeutic value in the management of sepsis, but human studies must be performed to provide strength to their potential clinical relevance in sepsis-related morbidity and mortality reduction.

Lycorine and organ protection: Review of its potential effects and molecular mechanisms

BACKGROUND

Multiorgan dysfunction, especially sepsis-related multiorgan damage, remains a major cause of high mortality in the late stages of infection and a great clinical challenge. In recent years, natural drugs have received widespread attention because of their low cost, wide sources, high efficacy, low toxicity, and limited side effects. Lycorine, a natural compound extracted from Amaryllidaceae, exhibits multiple pharmacological activities, including in the regulation of autophagy and the induction of cancer cell apoptosis, and has anti-inflammatory, antifungal, antiviral, antimalarial, and antitumor activities. However, studies on lycorine have mainly focused on its antitumor properties, and research on its use for organ protection, especially in sepsis-related organ injury, is relatively limited.

PURPOSE

To review and discuss the effects and mechanisms of lycorine in the treatment of multi-organ dysfunction, especially sepsis.

METHODS

Literature searches in electronic databases, such as Web of Science, Science Direct, PubMed, Google Scholar, and Scopus, were performed using 'Lycorine', 'Amaryllidaceae', 'Pharmacology', 'Pharmacokinetics', 'Anti-inflammation', 'Autophagy', 'Apoptosis', 'Anti-microbial and anti-parasitic', 'Antitumor', 'Organ protection', and 'Sepsis' as keywords, the correlated literature was extracted and conducted from the databases mentioned above.

RESULTS

By summarizing the progress made in existing research, we found that the general effects of lycorine involve the regulation of autophagy and the induction of cancer cell apoptosis, and anti-inflammatory, antifungal, antiviral, antimalarial, and antitumor effects; through these pathways, the compound can ameliorate organ damage. In addition, lycorine was found to have an important effect on organ damage in sepsis.

CONCLUSION

Lycorine is a promising natural organ protective agent. This review will provide a new theoretical basis for the treatment of organ protection, especially in sepsis.

The Polyphenolic Profile and Antioxidant Activity of Five Vegetal Extracts with Hepatoprotective Potential

Oxidative stress is among the major triggers for many important human functional disorders, which often lead to various metabolic or tissue diseases. The aim of the study is to obtain five standardized vegetal extracts (Cynarae extractum-CE, Rosmarini extractum-RE, Taraxaci extractum-TE, Cichorii extractum-CHE, and Agrimoniae extractum-AE) that contain active principles with an essential role in protecting liver cells against free radicals and quantify their antioxidant actions. The compounds of therapeutic interest from the analyzed extracts were identified and quantified using the UHPLC-HRMS/MS technique. Thus, the resulting identified compounds were 28 compounds in CE, 48 compounds in RE, 39 compounds in TE, 43 compounds in CHE, and 31 compounds in AE. These compounds belong to the class of flavonoids, isoflavones, phenolic acids and dicarboxylic acids, depsides, diterpenes, triterpenes, sesquiterpenes, proanthocyanidins, or coumarin derivatives. From the major polyphenolic compounds quantified in all the extracts analyzed by UHPLC-HRMS/MS, considerable amounts have been found for chlorogenic acid (619.8 µg/g extract for TE-2032.4 µg/g extract for AE), rutoside (105.1 µg/g extract for RE-1724.7 µg/g extract for AE), kaempferol (243 µg/g extract for CHE-2028.4 µg/g extract for CE), and for naringenin (383 µg/g extract for CHE-1375.8 µg/g extract for AE). The quantitative chemical analysis showed the highest content of total phenolic acids for AE (24.1528 ± 1.1936 g chlorogenic acid/100 g dry extract), the highest concentration of flavones for RE (6.0847 ± 0.3025 g rutoside/100 g dry extract), and the richest extract in total polyphenols with 31.7017 ± 1.2211 g tannic acid equivalent/100 g dry extract for AE. Several methods (DPPH, ABTS, and FRAP) have been used to determine the in vitro total antioxidant activity of the extracts to evaluate their free radical scavenging ability, influenced by the identified compounds. As a result, the correlation between the content of the polyphenolic compounds and the antioxidant effect of the extracts has been demonstrated. Statistically significant differences were found when comparing the antiradical capacity within the study groups. Although all the analyzed extracts showed good IC50 values, which may explain their antihepatotoxic effects, the highest antioxidant activity was obtained for Agrimoniae extractum (IC50ABTS = 0.0147 mg/mL) and the lowest antioxidant activity was obtained for Cynarae extractum (IC50ABTS = 0.1588 mg/mL). Furthermore, the hepatoprotective potential was evaluated in silico by predicting the interactions between the determined phytochemicals and key molecular targets relevant to liver disease pathophysiology. Finally, the evaluation of the pharmacognostic and phytochemical properties of the studied extracts validates their use as adjuvants in phytotherapy, as they reduce oxidative stress and toxin accumulation and thus exert a hepatoprotective effect at the cellular level.

Targeting HMGB1 for the treatment of sepsis and sepsis-induced organ injury

High mobility group box 1 (HMGB1) is a ubiquitous nuclear protein that is present in almost all cells and regulates the activity of innate immune responses in both intracellular and extracellular settings. Current evidence suggests that HMGB1 plays a pivotal role in human pathological and pathophysiological processes such as the inflammatory response, immune reactions, cell migration, aging, and cell death. Sepsis is a systemic inflammatory response syndrome (SIRS) that occurs in hosts in response to microbial infections with a proven or suspected infectious etiology and is the leading cause of death in intensive care units worldwide, particularly in the aging population. Dysregulated systemic inflammation is a classic characteristic of sepsis, and suppression of HMGB1 may ameliorate inflammation and improve patient outcomes. Here, we focus on the latest breakthroughs regarding the roles of HMGB1 in sepsis and sepsis-related organ injury, the ways by which HMGB1 are released, and the signaling pathways and therapeutics associated with HMGB1. This review highlights recent advances related to HMGB1: the regulation of HMBG1 might be helpful for both basic research and drug development for the treatment of sepsis and sepsis-related organ injury.

Magnolol protects against acute gastrointestinal injury in sepsis by down-regulating regulated on activation, normal T-cell expressed and secreted

BACKGROUND

Sepsis is a major medical challenge. Magnolol is an active constituent of Houpu that improves tissue function and exerts strong anti-endotoxin and anti-inflammatory effects, but the mechanism by which it reduces intestinal inflammation in sepsis is yet unclear.

AIM

To assess the protective effect of magnolol on intestinal mucosal epithelial cells in sepsis and elucidate the underlying mechanisms.

METHODS

Enzyme-linked immunosorbent assay was used to measure tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and regulated on activation, normal T-cell expressed and secreted (RANTES) levels in serum and ileal tissue in animal studies. The histopathological changes of the ileal mucosa in different groups were observed under a microscope. Cell Counting Kit-8 and cell permeability assays were used to determine the concentration of drug-containing serum that did not affect the activity of Caco2 cells but inhibited lipopolysaccharide (LPS)-induced decrease in permeability. Immunofluorescence and Western blot assays were used to detect the levels of RANTES, inhibitor of nuclear factor kappa-B kinase β (IKKβ), phosphorylated IKKβ (p-IKKβ), inhibitor of nuclear factor kappa-B kinase α (IκBα), p65, and p-p65 proteins in different groups in vitro.

RESULTS

In rats treated with LPS by intravenous tail injection in the presence or absence of magnolol, magnolol inhibited the expression of proinflammatory cytokines, IL-1β, IL-6, and TNF-α in a dose-dependent manner. In addition, magnolol suppressed the production of RANTES in LPS-stimulated sepsis rats. Moreover, in vitro studies suggested that magnolol inhibited the increase of p65 nucleation, thereby markedly downregulating the production of the phosphorylated form of IKKβ in LPS-treated Caco2 cells. Specifically, magnolol inhibited the translocation of the transcription factor nuclear factor-kappa B (NF-κB) from the cytosol into the nucleus and down-regulated the expression level of the chemokine RANTES in LPS-stimulated Caco2 cells.

CONCLUSION

Magnolol down-regulates RANTES levels by inhibiting the LPS/NF-κB signaling pathways, thereby suppressing IL-1β, IL-6, and TNF-α expression to alleviate the mucosal barrier dysfunction in sepsis.

Roles of RAGE/ROCK1 Pathway in HMGB1-Induced Early Changes in Barrier Permeability of Human Pulmonary Microvascular Endothelial Cell

Background

High mobility group box 1 (HMGB1) causes microvascular endothelial cell barrier dysfunction during acute lung injury (ALI) in sepsis, but the mechanisms have not been well understood. We studied the roles of RAGE and Rho kinase 1 (ROCK1) in HMGB1-induced human pulmonary endothelial barrier disruption.

Methods

In the present study, the recombinant human high mobility group box 1 (rhHMGB1) was used to stimulate human pulmonary microvascular endothelial cells (HPMECs). The endothelial cell (EC) barrier permeability was examined by detecting FITC-dextran flux. CCK-8 assay was used to detect cell viability under rhHMGB1 treatments. The expression of related molecules involved in RhoA/ROCK1 pathway, phosphorylation of myosin light chain (MLC), F-actin, VE-cadherin and ZO-1 of different treated groups were measured by pull-down assay, western blot and immunofluorescence. Furthermore, we studied the effects of Rho kinase inhibitor (Y-27632), ROCK1/2 siRNA, RAGE-specific blocker (FPS-ZM1) and RAGE siRNA on endothelial barrier properties to elucidate the related mechanisms.

Results

In the present study, we demonstrated that rhHMGB1 induced EC barrier hyperpermeability in a dose-dependent and time-dependent manner by measuring FITC-dextran flux, a reflection of the loss of EC barrier integrity. Moreover, rhHMGB1 induced a dose-dependent and time-dependent increases in paracellular gap formation accompanied by the development of stress fiber rearrangement and disruption of VE-cadherin and ZO-1, a phenotypic change related to increased endothelial contractility and endothelial barrier permeability. Using inhibitors and siRNAs directed against RAGE and ROCK1/2, we systematically determined that RAGE mediated the rhHMGB1-induced stress fiber reorganization via RhoA/ROCK1 signaling activation and the subsequent MLC phosphorylation in ECs.

Conclusion

HMGB1 is capable of disrupting the endothelial barrier integrity. This study demonstrates that HMGB1 activates RhoA/ROCK1 pathway via RAGE, which phosphorylates MLC inducing stress fiber formation at short time, and HMGB1/RAGE reduces AJ/TJ expression at long term independently of RhoA/ROCK1 signaling pathway.

Naringin improves sepsis-induced intestinal injury by modulating macrophage polarization via PPARγ/miR-21 axis

Naringin exhibited various pharmacological activities. However, its biological function and underlying mechanism in regulating macrophage polarization remain elusive. This study aimed to investigate the regulatory network between naringin and macrophage polarization in sepsis-induced intestinal injury. Cecal ligation and puncture (CLP) was used to establish the animal model of sepsis. Chromatin immunoprecipitation and a luciferase reporter assay were used to determine the interplay between peroxisome proliferator-activated receptor γ (PPARγ) and miR-21 promoter, as well as miR-21 and its target genes. Naringin enhanced the overall survival of septic mice and alleviated the CLP-induced inflammatory response and intestinal damage. This was accompanied by the increased expression of PPARγ in the intestines and the stimulation of ileal macrophages toward the M2 phenotype. Furthermore, in lipopolysaccharide-stimulated bone marrow-derived macrophages, naringin stimulated M2 polarization. Mechanistically, PPARγ inhibition attenuated the promotion of M2 polarization caused by naringin, and the naringin/PPARγ regulatory work was compromised by miR-21 inhibition. The present study suggested that naringin promoted M2 polarization via the PPARγ/miR-21 axis, thus relieving sepsis-induced intestinal injury. This study provides novel insights into the mechanism by which naringin alleviated sepsis-induced intestinal injury through regulation of macrophage polarization.

The protective role of YTHDF1-knock down macrophages on the immune paralysis of severe sepsis rats with ECMO

OBJECTIVE

To examine the role of YTHDF1 knock-down macrophages on the immunity of severe sepsis rats with ECMO.

METHODS

15 SD rats were randomly allocated into 3 groups: mild sepsis (I), severe sepsis with ECMO (II), and YTHDF1 knock-down macrophages treatment groups (III). Blood biochemical indexes, different immune factors and brain changes were detected by RT-PCR, ELISA, ELISPOT and HE staining. Isolated macrophages subtypes and signal proteins were detected by flow cytometry, western blot and m6A RNA methylation test.

RESULTS

The levels of HMGB1, RAGE, YTHDF1 and IL-17 in peripheral blood were significantly higher (p < 0.01), while the level of CXCL9 and TNF-α, and LPS-specific CD8+CTL function were significantly decreased in group II compared with group I (p < 0.01). The ratio of CD63+ macrophages (p < 0.05) and CD64+ macrophages (p< 0.05) decreased and the level of elastase (p < 0.01) and CCR2highCX3CR1low/CCR2lowCX3CR1high (p < 0.01) of macrophages increased in group II. The above were consistent with the severity of biochemical indicators, the increasing endothelial injury factor (Ang2/Ang1), lower endothelial protective factor (sTie2), severer brain injury in group II. After YTHDF1 knock-down macrophages treatment, the above indexes' changes were opposite when Group III versus Group II through the down-regulation of m6A RNA methylation of JAK2/STAT3 (p < 0.01) and protein expression of PJAK2/PSTAT3 (p < 0.05) in isolated macrophages.

CONCLUSIONS

YTHDF1 knock-down macrophages improved the immune paralysis of macrophages, Th1/Th17 and CTL and reduced the entry of macrophages into the brain to cause endothelial damage of severe sepsis rats with ECMO through the inhibition of HMGB1/RAGE and YTHDF1, m6A RNA methylation of JAK2/STAT3 and PJAK2/PSTAT3 proteins expression in macrophages.

Inorganic material based macrophage regulation for cancer therapy: basic concepts and recent advances

Macrophages with the M1 phenotype are a type of immune cell with exciting prospects for cancer therapy; however, when these macrophages infiltrate into tumours, many of them are induced by the tumour microenvironment to transform into the M2 type, which can enable tumour defence against external therapeutic strategies, assisting in tumour development. Macrophages have strong plasticity and functional heterogeneity, and their phenotypic transformation is complex and still poorly understood in relation to cancer therapy. Recent material advances in inorganic nanomaterials, especially inorganic elements in vivo, have accelerated the development of macrophage regulation-based cancer treatments. This review summarizes the basics of recent research on macrophage phenotype transformation and discusses the current challenges in macrophage type regulation. Then, the current achievements involving inorganic material-based macrophage regulation and the related anticancer effects of induced macrophages and their extracellular secretions are reviewed systematically. Importantly, inorganic nanomaterial-based macrophage phenotype regulation is flexible and can be adapted for different types of cancer therapies, presenting a possible novel approach for the generation of immune materials for cancer therapy.

The Effect and Regulatory Mechanism of High Mobility Group Box-1 Protein on Immune Cells in Inflammatory Diseases

High mobility group box-1 protein (HMGB1), a member of the high mobility group protein superfamily, is an abundant and ubiquitously expressed nuclear protein. Intracellular HMGB1 is released by immune and necrotic cells and secreted HMGB1 activates a range of immune cells, contributing to the excessive release of inflammatory cytokines and promoting processes such as cell migration and adhesion. Moreover, HMGB1 is a typical damage-associated molecular pattern molecule that participates in various inflammatory and immune responses. In these ways, it plays a critical role in the pathophysiology of inflammatory diseases. Herein, we review the effects of HMGB1 on various immune cell types and describe the molecular mechanisms by which it contributes to the development of inflammatory disorders. Finally, we address the therapeutic potential of targeting HMGB1.

Could Targeting HMGB1 be Useful for the Clinical Management of COVID-19 Infection?

Since the high mobility group box-1 (HMGB1) molecule had been recognized as a proinflammatory cytokine, which mediates endotoxin lethality of mice, there have been lots of papers about targeting the HMGB1 within the contexts of infection, inflammation, and cancer. The pathogenic impact of HMGB1 to the severe acute respiratory syndrome (SARS) and disease management with herbal formulations targeting this unique protein have already been proposed. However, the failure of the numerous current anti-viral therapies on the ongoing viral infections casts reappraisal of the possible interrelationships regarding the HMGB1 and SARS-CoV-2. COVID-19 pandemic due to the SARS-CoV-2 virus is a currently ongoing challenging global health crisis. There is still not any proven exact treatment of COVID-19 with high level of evidence. In this paper, we focused on the potential usage of external and/or inhalation preparation of antiviral/antibacterial herbal products capable of targeting HMGB1 for the clinical management candidates of the ongoing COVID-19 infection.

Targeting Neurological Manifestations of Coronaviruses by Candidate Phytochemicals: A Mechanistic Approach

The novel coronavirus 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made a wide range of manifestations. In this regard, growing evidence is focusing on COVID-19 neurological associations; however, there is a lack of established pathophysiological mechanisms and related treatments. Accordingly, a comprehensive review was conducted, using electronic databases, including PubMed, Scopus, Web of Science, and Cochrane, along with the author's expertize in COVID-19 associated neuronal signaling pathways. Besides, potential phytochemicals have been provided against neurological signs of COVID-19. Considering a high homology among SARS-CoV, Middle East Respiratory Syndrome and SARS-CoV-2, revealing their precise pathophysiological mechanisms seems to pave the road for the treatment of COVID-19 neural manifestations. There is a complex pathophysiological mechanism behind central manifestations of COVID-19, including pain, hypo/anosmia, delirium, impaired consciousness, pyramidal signs, and ischemic stroke. Among those dysregulated neuronal mechanisms, neuroinflammation, angiotensin-converting enzyme 2 (ACE2)/spike proteins, RNA-dependent RNA polymerase and protease are of special attention. So, employing multi-target therapeutic agents with considerable safety and efficacy seems to show a bright future in fighting COVID-19 neurological manifestations. Nowadays, natural secondary metabolites are highlighted as potential multi-target phytochemicals in combating several complications of COVID-19. In this review, central pathophysiological mechanisms and therapeutic targets of SARS-CoV-2 has been provided. Besides, in terms of pharmacological mechanisms, phytochemicals have been introduced as potential multi-target agents in combating COVID-19 central nervous system complications.

Early Prognosis Effect of Cellular Immune Paralysis on Brain Complications of Extracorporeal Membrane Oxygenation Children with Severe Sepsis

OBJECTIVE

The aim of the study was to explore the relationship between criticality, brain complications, and immune mechanisms in extracorporeal membrane oxygenation (ECMO) children with pneumonia and severe sepsis.

METHODS

Patients with simple pneumonia (group I), ECMO patients with pneumonia and severe sepsis accompanied by brain complications (group II), and those without brain complication (group III) admitted to our pediatric intensive care unit were selected to be investigated. The relationship among the peripheral blood subgroups of immune cells, immune factors, adaptive immune responses, endothelial factors, and criticality and brain complications was then studied.

RESULTS

Severe paralysis of normal immunity, excess abnormal immunity, and endothelial injury were consistent with the increase in the absolute value of base excess, lactic acid (Lac) content, and average hospitalization days and brain complications involved in group II (vs. group I). The ratio of CD63+ macrophage and CD63+ neutrophil subpopulation increased (p < 0.05); the expression levels of elastase+ neutrophil denatured subgroup (p < 0.05), the ratio of CCR2highCX3CR1low/CCR2lowCX3CR1high of macrophages and neutrophils (p < 0.0001), high-mobility group box 1 (HMGB1), YTHDF1, interleukin-17 protein and mRNA, and RAGE gene decreased to some extent (p < 0.05); the expression levels of Th1 cells chemokine CXCL9 protein and mRNA and sTIE2 protein increased to some extent (p < 0.05); the adaptive immune response of CD8+ CTL stimulated by lipopolysaccharide (LPS) was slightly enhanced (p < 0.05) in group III(vs. group II), which was consistent with the improvement of criticality, average hospitalization days, and the absence of brain complications in group III (vs. group II).

CONCLUSION

ECMO support with brain complication was related to the upregulation of HMGB1 and YTHDF1 protein; the decreased number of CD63+ macrophages and neutrophils; the increased denatured neutrophil subgroup, especially the upregulated ratio of CCR2highCX3CR1low/CCR2lowCX3CR1high of macrophages and neutrophils; the imbalance of Th17/Th1, LPS-specific CD8+ CTL adaptive immune response paralysis; and the reduced endothelial sTIE2 protein expression level which caused clinical deterioration and prolonged average hospitalization days.

Evaluation of Naringenin as a Promising Treatment Option for COPD Based on Literature Review and Network Pharmacology

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease characterized by incompletely reversible airflow limitation and seriously threatens the health of humans due to its high morbidity and mortality. Naringenin, as a natural flavanone, has shown various potential pharmacological activities against multiple pathological stages of COPD, but available studies are scattered and unsystematic. Thus, we combined literature review with network pharmacology analysis to evaluate the potential therapeutic effects of naringenin on COPD and predict its underlying mechanisms, expecting to provide a promising tactic for clinical treatment of COPD.

Recent advances in the study of progranulin and its role in sepsis

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. The mortality rate of in-hospital patients whose conditions are complicated by sepsis remains high in spite of intensive-care treatment, therefore placing a significant financial burden on the health care system. In recent years, progranulin (PGRN), a cysteine-rich secretory protein (CRISP), has been found to play a crucial role in sepsis. PGRN participates in the pathogenesis of sepsis via diverse pathways, including bacterial clearance, cell growth and survival, tissue repair, and the regulation of inflammation. PGRN knockout mice suffer from serious infectious processes, whereas therapeutic administration of recombinant PGRN to such mice enhances bacterial clearance and reduces organ injury and mortality rate. Even though PGRN plays an important role in regulating sepsis, its potential mechanisms have not been completely clarified. In this review, we summarize the most recent research advances in the study of PGRN and its role in sepsis.

The Role of HMGB1, a Nuclear Damage-Associated Molecular Pattern Molecule, in the Pathogenesis of Lung Diseases

Significance: High-mobility group protein box 1 (HMGB1), a ubiquitous nuclear protein, regulates chromatin structure and modulates the expression of many genes involved in the pathogenesis of lung cancer and many other lung diseases, including those that regulate cell cycle control, cell death, and DNA replication and repair. Extracellular HMGB1, whether passively released or actively secreted, is a danger signal that elicits proinflammatory responses, impairs macrophage phagocytosis and efferocytosis, and alters vascular remodeling. This can result in excessive pulmonary inflammation and compromised host defense against lung infections, causing a deleterious feedback cycle. Recent Advances: HMGB1 has been identified as a biomarker and mediator of the pathogenesis of numerous lung disorders. In addition, post-translational modifications of HMGB1, including acetylation, phosphorylation, and oxidation, have been postulated to affect its localization and physiological and pathophysiological effects, such as the initiation and progression of lung diseases. Critical Issues: The molecular mechanisms underlying how HMGB1 drives the pathogenesis of different lung diseases and novel therapeutic approaches targeting HMGB1 remain to be elucidated. Future Directions: Additional research is needed to identify the roles and functions of modified HMGB1 produced by different post-translational modifications and their significance in the pathogenesis of lung diseases. Such studies will provide information for novel approaches targeting HMGB1 as a treatment for lung diseases.

Flavonoid-mediated immunomodulation of human macrophages involves key metabolites and metabolic pathways

The ability of flavonoids to attenuate macrophage pro-inflammatory activity and to promote macrophage-mediated resolution of inflammation is still poorly understood at the biochemical level. In this study, we have employed NMR metabolomics to assess how therapeutically promising flavonoids (quercetin, naringenin and naringin) affect the metabolism of human macrophages, with a view to better understand their biological targets and activity. In vitro-cultured human macrophages were polarized to the pro-inflammatory M1 phenotype, through incubation with LPS + IFN-γ, and subsequently treated with each flavonoid. The metabolic signatures of pro-inflammatory polarization and of flavonoid incubations were then characterized and compared. The results showed that all flavonoids modulated the cells endometabolome with the strongest impact being observed for quercetin. Many of the flavonoid-induced metabolic variations were in the opposite sense to those elicited by pro-inflammatory stimulation. In particular, the metabolic processes proposed to reflect flavonoid-mediated immunomodulation of macrophages included the downregulation of glycolytic activity, observed for all flavonoids, anti-inflammatory reprogramming of the TCA cycle (mainly quercetin), increased antioxidant protection (quercetin), osmoregulation (naringin), and membrane modification (naringenin). This work revealed key metabolites and metabolic pathways involved in macrophage responses to quercetin, naringenin and naringin, providing novel insights into their immunomodulatory activity.

Macrophage-derived HMGB1 is dispensable for tissue fibrogenesis

Alarmins and damage-associated molecular patterns (DAMPs) are powerful inflammatory mediators, capable of initiating and maintaining sterile inflammation during acute or chronic tissue injury. Recent evidence suggests that alarmins/DAMPs may also trigger tissue regeneration and repair, suggesting a potential contribution to tissue fibrogenesis. High mobility group B1 (HMGB1), a bona fide alarmin/DAMP, may be released passively by necrotic cells or actively secreted by innate immune cells. Macrophages can release large amounts of HMGB1 and play a key role in wound healing and regeneration processes. Here, we hypothesized that macrophages may be a key source of HMGB1 and thereby contribute to wound healing and fibrogenesis. Surprisingly, cell-specific deletion approaches, demonstrated that macrophage-derived HMGB1 is not involved in tissue fibrogenesis in multiple organs with different underlying pathologies. Compared to control HMGB1Flox mice, mice with macrophage-specific HMGB1 deletion (HMGB1ΔMac) do not display any modification of fibrogenesis in the liver after CCL4 or thioacetamide treatment and bile duct ligation; in the kidney following unilateral ureter obstruction; and in the heart after transverse aortic constriction. Of note, even under thermoneutral housing, known to exacerbate inflammation and fibrosis features, HMGB1ΔMac mice do not show impairment of fibrogenesis. In conclusion, our study clearly establishes that macrophage-derived HMGB1 does not contribute to tissue repair and fibrogenesis.

Cathelicidin-WA attenuates LPS-induced inflammation and redox imbalance through activation of AMPK signaling

Dysregulated activation of inflammation is associated with the development and progression of many diseases. Generation of reactive oxygen species (ROS) has been shown to promote an inflammatory response. Cathelicidin peptides not only defend against the invasion of various microbes but also play an important role in regulating immune responses. The objective of this study was to investigate the effects and mechanisms of Cathelicidin-WA (CWA) on the inflammatory response and oxidative stress in macrophages. Our results showed that CWA efficiently attenuated lipopolysaccharide (LPS)-stimulated inflammation and oxidative stress both in vivo and in vitro. Mechanistically, we found that CWA significantly reduced the LPS-induced nuclear translocation of NF-κB, thus decreasing the production of the pro-inflammatory cytokines TNF-α and IL-6 in macrophages. On the other hand, CWA markedly promoted the nuclear translocation of Nrf2 via the AKT pathway and p38 signaling. This resulted in increased expression of the anti-oxidative genes NQO-1 and HO-1 and alleviated oxidative stress in LPS-stimulated macrophages. Interestingly, the effects of CWA were diminished when AMPK was knocked down. Consistently, we noticed that CWA failed to ameliorate the LPS-induced inflammatory response and oxidative stress in AMPK knockout mice. Furthermore, we discovered that LKB1 was essential for AMPK activation by CWA. These data demonstrated for the first time that CWA attenuated LPS-stimulated inflammation and redox imbalance through regulating LKB1-AMPK signaling. Such knowledge provides new insights into the mechanisms through which Cathelicidin peptides modulate immune responses.

miR-146b overexpression ameliorates lipopolysaccharide-induced acute lung injury in vivo and in vitro

Acute respiratory distress syndrome (ARDS) is a type of acute lung injury (ALI), which causes high morbidity and mortality. So far, effective clinical treatment of ARDS is still limited. Recently, miR-146b has been reported to play a key role in inflammation. In the present study, we evaluated the functional role of miR-146b in ARDS using the murine model of lipopolysaccharide (LPS)-induced ALI. The miR-146b expression could be induced by LPS stimulation, and miR-146b overexpression was required in the maintenance of body weight and survival of ALI mice; after miR-146b overexpression, LPS-induced lung injury, pulmonary inflammation, total cell and neutrophil counts, proinflammatory cytokines, and chemokines in bronchial alveolar lavage (BAL) fluid were significantly reduced. The promotive effect of LPS on lung permeability through increasing total protein, albumin and IgM in BAL fluid could be partially reversed by miR-146b overexpression. Moreover, in murine alveolar macrophages, miR-146b overexpression reduced LPS-induced TNF-α and interleukin (IL)-1β releasing. Taken together, we demonstrated that miR-146b overexpression could effectively improve the LPS-induced ALI; miR-146b is a promising target in ARDS treatment.

Cross-talk between insulin signalling and LPS responses in mouse macrophages

The effect of insulin priming on Il-10 expression, regulation of inflammatory cytokines and participation of intra-cellular signalling events, primarily ERK1/2 and PI3K/Akt, has been investigated in high glucose (HG) and/or lipopolysaccharide (LPS)-induced murine macrophages. Our results demonstrate that congruent with sharp increase in ERK1/2 and CREB phosphorylation, insulin stimulation in vitro promotes significant increase in Il-10 expression in mouse peritoneal macrophage and RAW 264.7 cells, both positive for anti-IRβ. Pharmacological inhibition of MEK/MAPK, but not PI3K/Akt cascade, abrogates CREB phosphorylation and Il-10 synthesis indicating functional relevance of insulin action. Conversely, priming with PI3K inhibitor wortmannin prevents insulin attenuation of HG- and/or LPS-induced p38 MAPK and NF-κB activation, Tnf-α, Il-1β expression as well as NO production. Congruent with reduced Il-10 expression, MEK inhibition abrogates insulin action allowing significant increase in Tlr4 expression and LPS response indicating insulin-induced Il-10 might have pivotal influence in regulation of chronic as well as acute inflammatory response.

Inhibitory effects of miR-25 targeting HMGB1 on macrophage secretion of inflammatory cytokines in sepsis

High mobility group box 1 (HMGB1) can promote the migration of macrophages and the release of inflammatory cytokines, functions associated with the occurrence of sepsis. The role of microRNA (miR)-25 in the targeted regulation of HMGB1 expression and the release of macrophage inflammatory cytokines remains uncharacterized. The present study investigated the association between miR-25, HMGB1 and sepsis by analyzing the expression of miR-25 and HMGB1 in patients with sepsis. The present study also investigated whether miR-25 serves a role in targeting the regulation of HMGB1 expression and macrophage inflammatory factor release. Patients with sepsis were selected from the Intensive Care Unit, and serum levels of HMGB1. The expression of miR-25 and HMGB1 in serum and peripheral blood mononuclear cells (PBMCs) was compared. Macrophages were cultured in vitro and divided into 5 groups following treatment with lipopolysaccharide (LPS). The expression levels of miR-25, HMGB1, phosphorylated (p-)p65, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and HMGB-1 were compared, and the migration ability of cells was investigated by Transwell assays. Compared with the healthy controls, patients with sepsis exhibited elevated expression of HMGB1 and decreased expression of miR-25 in serum and PBMCs. Following treatment with LPS, the expression of HMGB1 and p-p65 was elevated, and the expression of miR-25 was decreased in macrophages compared with untreated cells. Following transfection with miR-25 mimics and/or short interfering RNA-HMGB1, the expression of HMGB1 in macrophages decreased significantly, the expression of p-p65, HMGB-1, TNF-α and IL-6 in the culture solution were also decreased, and the migration ability of macrophages was attenuated. The present study suggests that miR-25 attenuated the induction of HMGB1 by LPS, decreased the activity of nuclear factor-κB and the transcriptional activation of TNF-α and IL-6, and suppressed the migration of macrophages. Inhibiting expression of miR-25 may serve a role in upregulating HMGB1 expression, promoting the secretion of inflammatory cytokines and resulting in sepsis.

Inflammatory cytokine expression in patients with sepsis at an intensive care unit

Sepsis is a systemic inflammatory response syndrome caused by infection of bacteria, fungi and/or viruses in clinical patients. It is known that inflammatory cytokine levels have an essential role in the progression of sepsis. The present study investigated the role of inflammatory markers in human peripheral blood mononuclear cells (hPBMCs) of patients with sepsis at an intensive care unit. In addition, the plasma levels of inflammatory cytokines were compared between sepsis patients and healthy individuals. The results demonstrated that the serum levels of interleukin-1, -17 and -6, as well as tumor necrosis factor-α, were upregulated in sepsis patients. The serum levels of high mobility group box 1 and C-reactive protein were increased in sepsis patients compared with those in healthy individuals. The expression levels of nuclear factor-κB-p65 and its inhibitor IκBα, as well as the ratio of CD25⁺ cells, and the levels of neutrophil gelatinase-associated lipocalin and peptidoglycan recognition protein were higher in hPBMCs in sepsis patients compared with those in healthy individuals. It was also indicated that balance of T helper type 1/2 cytokines was also disturbed in patients with sepsis compared with that in healthy individuals. In conclusion, these results indicated that inflammation is involved in the progression of sepsis by interfering with the expression of various molecules, suggesting a potential therapeutic strategy for the treatment of sepsis patients.

Effects of simvastatin on the function of splenic CD4+ and CD8+ T cells in sepsis mice

Simvastatin may be beneficial for treating sepsis due to its immune-regulating properties, although the mechanisms remain elusive. Herein, we hypothesized simvastatin may attenuate T cell dysfunction induced by sepsis. To test this hypothesis, we used a model based on cecal ligation and puncture (CLP) to induce sepsis in mice. Male C57BL/6 mice were pre-treated with simvastatin (0.2 μg/g of body weight) before CLP. The expression of B and T lymphocyte attenuator (BTLA) on splenic CD4⁺ T cells and T cell apoptosis, CD4⁺ and CD8⁺ T cells were quantified by flow cytometry. Immunohistochemical staining was performed to evaluate the loss of immune effector cells. Formation of TNF-α and interleukin 10 (IL-10) in the spleen and plasma levels of presepsin, IL-1β, and IL-6 were determined using enzyme-linked immunosorbent assay. Simvastatin markedly inhibited the reduction in cytokine secretion from lipopolysaccharide (LPS)-stimulated splenocytes. Simvastatin-treated mice had significantly decreased the percentages of negative costimulatory receptor BTLA on CD4 T cell expression. Simvastatin markedly reduced T cell apoptosis through downregulating the Fas/FasL expression and decrease the percentage of caspase-3 activity in spleen tissue. There was significantly less depletion of splenic CD4⁺ and CD8⁺ T cells in simvastatin-treated mice. Simvastatin reduced plasma levels of presepsin, IL-1β, and IL-6. Simvastatin can be a powerful regulator of immune function under sepsis conditions by improving T cell function in sepsis.

Naringin attenuates MLC phosphorylation and NF-κB activation to protect sepsis-induced intestinal injury via RhoA/ROCK pathway

BACKGROUND

Sepsis is commonly associated with excessive stimulation of host immune system and result in multi-organ failure dysfunction. Naringin has been reported to exhibit a variety of biological effects. The present study aimed to investigate the protective effect of naringin on sepsis-induced injury of intestinal barrier function in vivo and in vitro.

METHODS

Mice were randomly divided into 4 groups named sham (n = 20), CLP + vehicle (n = 20), CLP + NG (30 mg/kg) (n = 20) and CLP + NG (60 mg/kg) (n = 20) groups. Sepsis was induced by cecal ligation and puncture (CLP). H&E staining and transmission electron microscopy (TEM) were performed to observe intestinal mucosal morphology. ELISA was used to determine the intestinal permeability and inflammatory response in vivo and in vitro. Western blot and RhoA activity assay were performed to determine the levels of tight junction proteins and the activation of indicated signaling pathways. MTT assay was used to determine cell viability.

RESULTS

Naringin improved survival rate of CLP mice and alleviated sepsis-induced intestinal mucosal injury. Furthermore, naringin improved impaired intestinal permeability and inhibited the release of TNF-α and IL-6, while increased IL-10 level in CLP mice and lipopolysaccharide (LPS)-stimulated MODE-K cells in a dose-dependent manner. Naringin increased the expression of tight junction proteins ZO-1 and claudin-1 via RhoA/ROCK/NF-κB/MLCK/MLC signaling pathway in vivo and in vitro.

CONCLUSION

Naringin improved sepsis-induced intestinal injury via RhoA/ROCK/NF-κB/MLCK/MLC signaling pathway in vivo and in vitro.

Tussilagone Inhibits the Inflammatory Response and Improves Survival in CLP-Induced Septic Mice

Tussilagone, extracted from Tussilago farfara is an oriental medicine used for asthma and bronchitis. We investigated its mechanism of action, its inhibitory effects on lipopolysaccharide-induced inflammation in macrophages, and its impact on viability in a cecal ligation and puncture (CLP)-induced mouse model of sepsis. Tussilagone suppressed the expression of the inflammatory mediators, nitric oxide and prostaglandin E2, and the inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1), in lipopolysaccharide-stimulated RAW 264.7 cells and peritoneal macrophages. Tussilagone also reduced the activation of the mitogen-activated protein kinases and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) involved in the activation of various inflammatory mediators in activated macrophages. Moreover, tussilagone administration (1 mg/kg and 10 mg/kg) produced decreased mortality and lung injury in CLP-activated septic mice. Augmented expression of cyclooxygenase (COX)-2 and TNF-α in pulmonary alveolar macrophages of septic mice were attenuated by tussilagone administration. Tussilagone also suppressed the induction of nitric oxide, prostaglandin E2, TNF-α and HMGB1 in the serum of the septic mice. Overall, tussilagone exhibited protective effects against inflammation and polymicrobial sepsis by suppressing inflammatory mediators possibly via the inhibition of NF-κB activation and the MAP kinase pathway. These results suggest the possible use of tussilagone for developing novel therapeutic modalities for sepsis and other inflammatory diseases.

Cereblon deficiency confers resistance against polymicrobial sepsis by the activation of AMP activated protein kinase and heme-oxygenase-1

Cereblon (CRBN) has a pleiotropic role in important cellular processes and is a potential therapeutic target in several diseases, including mental retardation, cancer, and metabolic disorders. The role of CRBN in polymicrobial sepsis induced by cecal ligation and puncture (CLP) was investigated using CRBN-deficient (KO) mice. Survival following CLP was significantly higher in KO mice compared to wild-type (WT) controls (50% vs 0% at day 6 after CLP). The improved survival of KO mice was accompanied by reduced peripheral blood bacterial load and lung injury. Serum tumor necrosis factor (TNF)-α and high mobility group box 1 (HMGB1) concentrations were significantly lower in KO mice than in WT mice. Peritoneal macrophages from KO mice with CLP-induced septic mouse had higher levels of activation of AMPK and heme oxygenase-1 (HO-1). Forced expression of CRBN in macrophage of KO mice suppressed activation of 5' adenosine monophosphate-activated protein kinase (AMPK) and HO-1 and augmented expression of TNF-α and HMGB1 as inhibition of AMPK by compound C. These studies demonstrate the contribution of CRBN expression to the pathogenesis of CLP-induced sepsis and peritoneal macrophage responses and suggest a novel therapeutic modality for polymicrobial sepsis.

Naringin prevents the inhibition of intestinal Ca2+ absorption induced by a fructose rich diet

This study tries to elucidate the mechanisms by which fructose rich diets (FRD) inhibit the rat intestinal Ca²⁺ absorption, and determine if any or all underlying alterations are prevented by naringin (NAR). Male rats were divided into: 1) controls, 2) treated with FRD, 3) treated with FRD and NAR. The intestinal Ca²⁺ absorption and proteins of the transcellular and paracellular Ca²⁺ pathways were measured. Oxidative/nitrosative stress and inflammation parameters were evaluated. FRD rats showed inhibition of the intestinal Ca²⁺ absorption and decrease in the protein expression of molecules of both Ca²⁺ pathways, which were blocked by NAR. FRD rats showed an increase in the superoxide anion, a decrease in the glutathione and in the enzymatic activities of the antioxidant system, as well as an increase in the NO content and in the nitrotyrosine content of proteins. They also exhibited an increase in both IL-6 and nuclear NF-κB. All these changes were prevented by NAR. In conclusion, FRD inhibit both pathways of the intestinal Ca²⁺ absorption due to the oxidative/nitrosative stress and inflammation. Since NAR prevents the oxidative/nitrosative stress and inflammation, it might be a drug to avoid alteration in the intestinal Ca²⁺ absorption caused by FRD.