AlCl3 inhibits LPS-induced NLRP3 inflammasome activation and IL-1β production through suppressing NF-κB signaling pathway in murine peritoneal macrophages

Study on the chronic inflammatory injury caused by Ageratina adenophora on goat liver using metabolomics

Ageratina adenophora (A. adenophora) is an invasive plant that is harmful to animals. The plants toxic effects on the liver have been studied in detail, however, the inflammation aspects of the hepatotoxicity are rarely discussed in literature. Therefore, in this study, we investigated the level of inflammation and the associated changes in liver metabolism caused by A. adenophora ingestion. Goat were fed with A. adenophora powder which accounts for 40% of the forage for 90 d. After the feeding period, the liver tissues were collected and the level of inflammation was detected using H & E staining and the changes in metabolites by LC-MS/MS. The results indicated that A. adenophora changes the liver metabolites, The test group shown 153 different metabolites in liver of which 71 were upregulated and 82 down regulated. We also found two differential metabolic pathways: neuroactive ligand-receptor interaction and pyrimidine metabolism. The changes in the pathway suggested an association with inflammation and with pathological processes such as oxidative stress and apoptosis. In addition, we observed an increase in the levels of serum liver function indexes (AST and ALT), indicating the liver injury. Furthermore, inflammatory cell infiltration and cell degeneration were observed in histopathological sections. In conclusion, this study reveals that A. adenophora causes chronic inflammation and upregulate metabolites related to inflammation in the liver. The study complements the research content of A. adenophora hepatotoxicity and provides a basis for further research by analyzing changes in the liver metabolites.

A review of the epidemiological and laboratory evidence of the role of aluminum exposure in pathogenesis of cardiovascular diseases

The objective of the present study was to review the epidemiological and laboratory evidence on the role of aluminum (Al) exposure in the pathogenesis of cardiovascular diseases. Epidemiological data demonstrated an increased incidence of cardiovascular diseases (CVD), including hypertension and atherosclerosis in occupationally exposed subjects and hemodialysis patients. In addition, Al body burden was found to be elevated in patients with coronary heart disease, hypertension, and dyslipidemia. Laboratory studies demonstrated that Al exposure induced significant ultrastructural damage in the heart, resulting in electrocardiogram alterations in association with cardiomyocyte necrosis and apoptosis, inflammation, oxidative stress, inflammation, and mitochondrial dysfunction. In agreement with the epidemiological findings, laboratory data demonstrated dyslipidemia upon Al exposure, resulting from impaired hepatic lipid catabolism, as well as promotion of low-density lipoprotein oxidation. Al was also shown to inhibit paraoxonase 1 activity and to induce endothelial dysfunction and adhesion molecule expression, further promoting atherogenesis. The role of Al in hypertension was shown to be mediated by up-regulation of NADPH-oxidase, inhibition of nitric oxide bioavailability, and stimulation of renin-angiotensin-aldosterone system. It has been also demonstrated that Al exposure targets cerebral vasculature, which may be considered a link between Al exposure and cerebrovascular diseases. Findings from other tissues lend support that ferroptosis, pyroptosis, endoplasmic reticulum stress, and modulation of gut microbiome and metabolome are involved in the development of CVD upon Al exposure. A better understanding of the role of the cardiovascular system as a target for Al toxicity will be useful for risk assessment and the development of treatment and prevention strategies.

Necroptosis and NLPR3 inflammasome activation mediated by ROS/JNK pathway participate in AlCl3-induced kidney damage

Aluminum (Al) is a common environmental pollutant that can induce kidney damage. However, the mechanism is not clear. In the present study, to explored the exact mechanism of AlCl₃-induced nephrotoxicity, C57BL/6 N male mice and HK-2 cells were used as experimental subjects. Our results showed that Al induced reactive oxygen species (ROS) overproduction, c-Jun N-terminal kinase (JNK) signaling activation, RIPK3-dependent necroptosis, NLRP3 inflammasome activation, and kidney damage. In addition, inhibiting JNK signaling could downregulate the protein expressions of necroptosis and NLRP3 inflammasome, thereby alleviating kidney damage. Meanwhile, clearing ROS effectively inhibited JNK signaling activation, which in turn inhibited necroptosis and NLRP3 inflammasome activation, ultimately alleviating kidney damage. In conclusion, these findings suggest that necroptosis and NLPR3 inflammasome activation mediated by ROS/JNK pathway participate in AlCl₃-induced kidney damage.

Effect of the Lipoxin Receptor Agonist BML-111 on Cigarette Smoke Extract-Induced Macrophage Polarization and Inflammation in RAW264.7 Cells

Background

Macrophages are known to play a crucial role in the chronic inflammation associated with Chronic Obstructive Pulmonary Disease (COPD). BML-111, acting as a lipoxin A4 (LXA4) receptor agonist, has shown to be effective in protecting against COPD. However, the precise mechanism by which BML-111 exerts its protective effect remains unclear.

Methods

In order to establish a cell model of inflammation, cigarette smoke extract (CSE) was used on the RAW264.7 cell line. Afterwards, an Enzyme-linked immunosorbent assay (ELISA) kit was employed to measure concentrations of tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), interleukin-18 (IL-18), and interleukin-10 (IL-10) in the cell supernatants of the RAW264.7 cells.In this study, we examined the markers of macrophage polarization using two methods: quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. Additionally, we detected the expression of Notch-1 and Hes-1 through Western blotting.

Results

BML-111 effectively suppressed the expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-18, as well as inflammasome factors NLRP3 and Caspase-1, while simultaneously up-regulating the expression of the anti-inflammatory cytokine IL-10 induced by CSE. Moreover, BML-111 reduced the expression of iNOS, which is associated with M1 macrophage polarization, and increased the expression of Arg-1, which is associated with M2 phenotype. Additionally, BML-111 downregulated the expression of Hes-1 and the ratio of activated Notch-1 to Notch-1 induced by CSE. The effect of BML-111 on inflammation and macrophage polarization was reversed upon administration of the Notch-1 signaling pathway agonist Jagged1.

Conclusion

BML-111 has the potential to suppress inflammation and modulate M1/M2 macrophage polarization in RAW264.7 cells. The underlying mechanism may involve the Notch-1 signaling pathway.

T-2 Toxin Caused Mice Testicular Inflammation Injury via ROS-Mediated NLRP3 Inflammasome Activation

T-2 toxin treatment causes male reproduction system dysfunction, although the exact mechanism remains unclear. In this research, male Kunming mice and TM4 cells were treated with varying concentrations of the T-2 toxin for evaluating the adverse effect of T-2 toxin on male reproductive function. MCC950 or NAC was used to block NLRP3 inflammasome activation and eliminate reactive oxygen species (ROS) accumulation in the TM4 cell, respectively. The results showed that: (1) T-2 toxin caused testicular atrophy, destroyed the microstructure and ultrastructure of the testis, and caused sperm deformities; (2) T-2 toxin increased the content and gene expressions of TNF-α and IL-6 and decreased the IL-10 content and gene expression, causing testis and TM4 cell inflammatory injury; (3) T-2 toxin activated NLRP3 inflammasome in the testis and TM4 cells and caused ROS accumulation in the testis; (4) suppressing NLRP3 inflammasome activation using 20 nM MCC950 alleviated the TM4 cell inflammatory damage caused via the T-2 toxin; nevertheless, 20 nM MCC950 did not reduce ROS accumulation in TM4 cells; and (5) NAC relieved the inflammatory damage in TM4 cells by inhibiting NLRP3 inflammasome activation. Taken together, T-2 toxin caused testicular inflammation injury through ROS-mediated NLRP3 inflammasome activation, resulting in male reproductive dysfunction.

Aluminum induced intestinal dysfunction via mechanical, immune, chemical and biological barriers

Aluminum is the most abundant metal element in the Earth's crust, which exists naturally in the form of aluminum compounds. Aluminum is mainly absorbed through the gastrointestinal tract, which varies with different aluminum compounds. During this process, aluminum could induce the disruption of intestinal mucosa barrier. However, its underlying mechanism has not been elucidated yet. Previous studies have reported that aluminum can firstly promote the apoptosis of intestinal epithelial cells, destroy the structure of tight-junction proteins, and increase the intestinal permeability, injuring the mechanical barrier of gut. Also, it can induce the activation of immune cells to secrete inflammatory factors, and trigger immune responses, interfering with immune barrier. Moreover, aluminum treatment can regulate intestinal composition and bio-enzyme activity, impairing the function of chemical barrier. In addition, aluminum accumulation can induce an imbalance of the intestinal flora, inhibit the growth of beneficial bacteria, and promote the proliferation of harmful bacteria, which ultimately disrupting biological barrier. Collectively, aluminum may do extensive damage to intestinal barrier function covering mechanical barrier, immune barrier, chemical barrier and biological barrier.

Seabuckthorn Berries Extract Attenuates Pulmonary Vascular Hyperpermeability in Lipopolysaccharide-Induced Acute Lung Injury in Mice

Objective

To investigate the effect of seabuckthorn berries extract (SBE) on pulmonary vascular hyperpermeability in the mice model of acute lung injury (ALI) induced by lipopolysaccharide (LPS).

Methods

Sixty Kunming mice were allocated into 6 groups by a random number table, including control, LPS, dexamethasone (Dex, 1 mg/kg), and 120, 240 and 480 mg/kg SBE groups, 10 mice in each group. Except the control group, mice were pre-treated with Dex and SBE, respectively, for 7 days before LPS was intraperitoneally injected to induce ALI. Pulmonary vascular hyperpermeability was evaluated by histopathologic observation and transvascular leakage determination. Tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) levels in serum were measured using enzyme-linked immunosorbent assay. The expression of nuclear factor-kappa B (NF-κB) p65 in lung cells was determined by immunofluorescence analysis. The contents of cytoplasmic inhibitor of nuclear factor-κB kinase (IKK) and nuclear p65, as well as downstream proteins of E-selectin (CD62E) and intercellular adhesion molecule-1 (ICAM-1), were determined using Western blot analysis.

Results

Histopathological observation confirmed SBE treatment alleviated morphological lesion induced by LPS. Compared with the LPS group, 480 mg/kg SBE significantly decreased the water content of lung, Evans blue accumulation in lung tissue, and protein concentration and neutrophils count in bronchoalveolar lavage fluid (P<0.01); moreover, 480 mg/kg SBE significantly suppressed release of TNF-α and IL-6, and down-regulated expressions of IKK, nuclear p65, ICAM-1 and CD62E (P<0.01).

Conclusion

SBE maintained alveolar-capillary barrier integrity under endotoxin challenge in mice by suppressing the key factors in the pathogenesis of ALI.

Electronic Supplementary Material

Supplementary material (Appendix 1) is available in the online version of this article at 10.1007/s11655-021-3346-1.

Protection of Sacubitril/Valsartan against Pathological Cardiac Remodeling by Inhibiting the NLRP3 Inflammasome after Relief of Pressure Overload in Mice

Background/aims

The persistent existence of pathological cardiac remodeling, resulting from aortic stenosis, is related to poor clinical prognosis after successful transcatheter aortic valve replacement (TAVR). Sacubitril/valsartan (Sac/Val), comprising an angiotensin receptor blocker and a neprilysin inhibitor, has been demonstrated to have a beneficial effect against pathological cardiac remodeling, including cardiac fibrosis and inflammation in heart failure. The aim of this study was to determine whether Sac/Val exerts a cardioprotective effect after pressure unloading in mice.

Methods and results

Male C57BL/6 J mice were subjected to debanding (DB) surgery after 8 weeks (wk) of aortic banding (AB). Cardiac function was assessed by echocardiography, which indicated a protective effect of Sac/Val after DB. After treatment with Sac/Val post DB, decreased heart weight and myocardial cell size were observed in mouse hearts. In addition, histological analysis, immunofluorescence, and western blot results showed that Sac/Val attenuated cardiac fibrosis and inflammation after DB. Finally, our data indicated that Sac/Val treatment could significantly suppress NF-κB signaling and NLRP3 inflammasome activation in mice after relief of pressure overload.

Conclusion

Sac/Val exerted its beneficial effects to prevent maladaptive cardiac fibrosis and dysfunction in mice following pressure unloading, which was at least partly due to the inhibition of NLRP3 inflammasome activation.

Electronic supplementary material

The online version of this article (10.1007/s10557-020-06995-x) contains supplementary material, which is available to authorized users.

Biosurfactants of Lactobacillus helveticus for biodiversity inhibit the biofilm formation of Staphylococcus aureus and cell invasion

Aim: This study aimed to evaluate the differences of biosurfactants produced by two Lactobacillus helveticus strains against the biofilm formation of Staphylococcus aureus in vitro and in vivo. Materials & methods: Scanning electron microscopy, Real time-quantitative PCR (RT-qPCR) and cell assay were used to analyze the inhibiting effect of biosurfactants against biofilm formation. Results & conclusion: Results showed that the biosurfactants have anti-adhesive and inhibiting effects on biofilm formation in vivo and in vitro. The biofilm-formative genes and autoinducer-2 signaling regulated these characteristics, and the biosurfactant L. helveticus 27170 is better than that of 27058. Host cell adhesion and invasion results indicated that the biosurfactants L. helveticus prevented the S. aureus invading the host cell, which may be a new strategy to eliminate biofilms.

Environmentally relevant doses of tetrabromobisphenol A (TBBPA) cause immunotoxicity in murine macrophages

TBBPA is one of the main brominated flame retardants and is ubiquitous in the environment. TBBPA can directly encounter immune cells via the bloodstream, posing potential immunotoxicity. To understand the immunomodulating effect of TBBPA on macrophages, the murine macrophages, RAW 264.7, were exposed to TBBPA at environmentally relevant concentrations (1-100 nM). The results showed that TBBPA at the selected concentrations did not alter cell viability of RAW 264.7 cells with or without LPS stimulation. TBBPA upregulated the expression of pro-inflammatory cytokines, including IL-1β, IL-6, and TNF-α, whereas it attenuated the LPS-stimulated expression of these pro-inflammatory cytokines, and the expression of anti-inflammatory cytokines, including IL-4, IL-10, and IL-13. In addition, TBBPA reduced the mRNA levels of antigen-presenting-related genes, including H2-K2, H2-Aa, Cd80, and Cd86. Moreover, TBBPA impaired the phagocytic activity of macrophages. Furthermore, exposure to TBBPA significantly elevated the protein levels of phosphorylated NF-κB p65 (p-p65), while it reduced LPS-stimulated p-p65 protein levels. DCFH-DA staining assays showed that TBBPA caused a slight but significant elevation in reactive oxygen species levels. The data obtained in the present study demonstrated that exposure to environmentally relevant concentrations of TBBPA posed immunotoxicity in macrophages and unveiled a potential health risk of TBBPA.

TAF and TDF attenuate liver fibrosis through NS5ATP9, TGFβ1/Smad3, and NF-κB/NLRP3 inflammasome signaling pathways

BACKGROUND

This study aimed to investigate the roles and mechanisms of tenofovir alafenamide fumarate (TAF)/tenofovir disoproxil fumarate (TDF) in treating liver fibrosis.

METHODS

The effects of TAF/TDF on carbon tetrachloride (CCl₄)-induced liver fibrosis in C57BL/6 wild-type or nonstructural protein 5A transactivated protein 9 (NS5ATP9) knockout mice were studied. The differentiation, activation, and proliferation of LX-2 cells after TAF/TDF treatment were tested in vitro. The expression of NS5ATP9 and activities of transforming growth factor-β1 (TGFβ1)/Sekelsky mothers against decapentaplegic homolog 3 (Smad3) and NF-κB/NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome signaling pathways were detected in TAF/TDF-treated mice and LX-2 cells. The genes related to extracellular matrix accumulation were detected in vivo and in vitro after NS5ATP9 silencing or knockout.

RESULTS

TAF/TDF significantly inhibited CCl₄-induced liver fibrosis in mice, and regulated the differentiation, activation, and proliferation of hepatic stellate cells (HSCs). Furthermore, TAF/TDF suppressed the activities of TGFβ1/Smad3 and NF-κB/NLRP3 inflammasome signaling pathways in vivo and in vitro. NS5ATP9 inhibited liver fibrosis through TGFβ1/Smad3 and NF-κB signaling pathways. TAF/TDF upregulated the expression of NS5ATP9 in vivo and in vitro. Finally, TAF/TDF could only show marginal therapeutic effects when NS5ATP9 was silenced and knocked out in vivo and in vitro.

CONCLUSIONS

TAF/TDF prevented progression and promoted reversion of liver fibrosis through assembling TGFβ1/Smad3 and NF-κB/NLRP3 inflammasome signaling pathways via upregulating the expression of NS5ATP9. TAF/TDF also regulated the differentiation, activation, and proliferation of HSCs. The findings provided strong evidence for the role of TAF/TDF as a new promising therapeutic strategy in liver fibrosis.

Taurine Alleviates Schistosoma-Induced Liver Injury by Inhibiting the TXNIP/NLRP3 Inflammasome Signal Pathway and Pyroptosis

Schistosomiasis is a parasitic helminth disease that can cause severe inflammatory pathology, leading to organ damage, in humans. During a schistosomal infection, the eggs are trapped in the host liver, and products derived from eggs induce a polarized Th2 cell response, resulting in granuloma formation and eventually fibrosis. Previous studies indicated that the nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is involved in schistosomiasis-associated liver fibrosis and that taurine could ameliorate hepatic granulomas and fibrosis caused by Schistosoma japonicum infection. Nevertheless, the precise role and molecular mechanism of the NLRP3 inflammasome and the protective effects of taurine in S. japonicum infection have not been extensively studied. In this study, we investigated the role of the NLRP3 inflammasome and the hepatoprotective mechanism of taurine in schistosoma-induced liver injury in mice. NLRP3 deficiency ameliorated S. japonicum-infection-induced hepatosplenomegaly, liver dysfunction, and hepatic granulomas and fibrosis; it also reduced NLRP3-dependent liver pyroptosis. Furthermore, taurine suppressed hepatic thioredoxin-interacting protein (TXNIP)/NLRP3 inflammasome activation in mice with S. japonicum infections, thereby inhibiting the activation of downstream inflammatory mediators such as interleukin-1β and subsequent pyroptosis. Our results suggest that the TXNIP/NLRP3 inflammasome pathway and mediating pyroptosis are involved in S. japonicum-induced liver injury and may be a potential therapeutic target for schistosomiasis treatment. In addition, taurine may be useful to alleviate or to prevent the occurrence of schistosomiasis-associated liver fibrosis.

The therapeutic effect of verapamil in lipopolysaccharide-induced acute lung injury

The objective of this study was to investigate the exact therapeutic effects of Verapamil on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the molecular mechanism involved, through using LPS-induced animal models as well as LPS-stimulated mouse primary peritoneal macrophages models. Our results demonstrated that Verapamil reduced LPS-induced pathological damage of the lung tissue, infiltration of inflammatory cells and the production of IL-1β, TNF-α, and MCP-1 in the serum. The MPO activity, MDA content, lung wet/dry ratio and LDH activity were also attenuated by Verapamil. In addition, Verapamil attenuated LPS-induced inflammatory cytokine production and oxidative stress in primary murine peritoneal macrophages in vitro. Moreover, we confirmed that NF-κB/NLRP3 pathway was involved in the therapeutic effect of Verapamil against LPS-induced injury in vivo and in vitro. In conclusion, these findings indicate that Verapamil has a therapeutic effect on LPS-induced ALI in mice. The mechanism may be related to the inhibition of NF-κB and NLRP3 signaling pathways. Verapamil may be a potential therapeutic agent for the treatment of ALI.

Ageratina adenophora causes spleen toxicity by inducing oxidative stress and pyroptosis in mice

Ageratina adenophora is an invasive weed with potent toxicological effects on livestock. Oxidative stress and pyroptosis play a pivotal role in regulating animal or human health and disease. The object of this study was to determine the mechanism underlying splenic toxicity induced by A. adenophora in a mouse model. Ageratina adenophora significantly increased the levels of reactive oxygen species and malondialdehyde, but decreased the antioxidants like catalase, superoxide dismutase, glutathione and glutathione peroxidase. In addition, the activity of the antioxidant enzymes was also decreased upon A. adenophora treatment. The induction of the pyroptosis pathway was evaluated in terms of the expression levels of Nod-like receptor protein 3, nuclear factor-κB, caspase-1, gasdermin-D and interleukin-1β, all of which were significantly elevated by A. adenophora. These findings suggest that A. adenophora impairs spleen function in mice through oxidative stress damage and pyroptosis.

Suppression of NLRP3 inflammasome improves alveolar bone defect healing in diabetic rats

Background

Excessive inflammatory response under hyperglycemia can impair alveolar bone defect healing under diabetic conditions. NLRP3 (NACHT [nucleotide-binding oligomerization], LRR [leucine-rich repeat], and PYD [pyrin domain] domains-containing protein 3) inflammasome has been considered to play a crucial role in the inflammatory response, but its correlation with the impaired alveolar bone repair in diabetes still remains unclarified. The objective of the current study is to investigate the effect of NLRP3 inflammasome inhibition by a lentiviral short hairpin RNA (shRNA) targeting NLRP3 on alveolar bone defect healing in diabetic rats.

Methods

Diabetes was induced in rats by high-fat diet and streptozotocin injection, and alveolar bone defects in both maxillae were created by surgery. Then, the lentiviral shRNA targeting NLRP3 was applied in the defect. Eight weeks after surgery, the alveolar bone regeneration was examined using hematoxylin and eosin (H&E) staining, and the gene expression in the bone healing site was detected using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analysis and western blot analysis.

Results

H&E staining showed that treatment with lentiviral shRNA targeting NLRP3 could increase the bone regeneration score in the alveolar bone defect of diabetic rats. Additionally, qRT-PCR analysis and western blot analysis of the bone defect demonstrated that this shRNA inhibited the expression of NLRP3, apoptosis-associated speck-like protein containing a CARD, caspase-1, and proinflammatory cytokine interleukin-1β and increased the expression of osteogenic markers Runt-related transcription factor 2 and osteocalcin.

Conclusions

Our findings suggested that inhibition of NLRP3 inflammasome could improve alveolar bone defect healing in diabetic rats. The beneficial effect may correlate with reduced proinflammatory cytokine production and increased osteogenic gene expression in hyperglycemia.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1215-9) contains supplementary material, which is available to authorized users.