Nuclear factor-κB Signaling Pathway Research Articles

Design, synthesis fusidic acid derivatives alleviate acute lung injury via inhibiting MAPK/NF-κB/NLRP3 pathway

Acute lung injury (ALI) refers to a series of lung lesions resulting from multiple lung injuries, even leading to morbidity and death, abundant previous reports have showed that anti-inflammatory as a key to treatment of ALI. Fusidic acid (FA) as an antibiotic has significant anti-bacterial activity and anti-inflammatory effects. In this study, we designed and synthesized 34 FA derivatives to identify new anti-inflammatory drugs. The anti-inflammatory activities of the derivatives were screened using lipopolysaccharide (LPS)-induced RAW264.7 cells to evaluate the anti-inflammatory activity of the compounds, we measured nitric oxide (NO) and interleukin-6 (IL-6). Most of compounds showed inhibitory effects on inflammatory NO and IL-6 in LPS-induced RAW264.7 cells. Based on the screening results, compound a1 showed the strongest anti-inflammatory activity. Compared with FA, the inhibition rate NO and IL-6 of compound a1 increased 3.08 and 2.09 times at 10 μM, respectively. We further measured a1 inhibited inflammatory factor NO (IC50 = 3.26 ± 0.42 μM), IL-6 (IC50 = 1.85 ± 0.21 μM) and TNF-α (IC50 = 3.88 ± 0.55 μM). We also demonstrated that a1 markedly inhibits the expression of certain immune-related cytotoxic factors, including cyclooxygenase-2 (COX-2) and inducible nitric-oxide synthase (iNOS). In vivo results indicate that a1 can reduce lung inflammation and NO, IL-6, TNF-α, COX-2 and iNOS in LPS-induced ALI mice. On the one hand, we demonstrated a1 inhibits the mitogen-activated protein kinase (MAPK) signaling pathway by down-regulating the phosphorylation of p38 MAPK, c-Jun N-terminal kinase (c-JNK) and extracellular signal-regulated kinase (ERK). Moreover, a1 also suppressing the phosphorylation of inhibitory NF-κB inhibitor α (IκBα) inhibits the activation of the nuclear factor-κB (NF-κB) signaling pathway. On the other hand, we demonstrated a1 also role in anti-inflammatory by inhibits nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome and further inhibits Caspase-1 and inflammatory factor interleukin-1β (IL-1β). In conclusion, our study demonstrates that a1 has an anti-inflammatory effect and alleviates ALI by regulating inflammatory mediators and suppressing the MAPK, NF-κB and NLRP3 inflammasome signaling pathways.

Effects of Buyang Huanwu Decoction and Astragali Radix-Angelicae Sinensis Radix combination on inflammatory responses in atherosclerotic mice

The study aims to observe the effects and explore the mechanisms of Buyang Huanwu Decoction and Astragali Radix-Angelicae Sinensis Radix combination in the treatment of the inflammatory response of mice with atherosclerosis(AS) via the Toll-like receptor 4(TLR4)/myeloid differentiation primary response protein 88(MyD88)/nuclear factor-κB(NF-κB) signaling pathway. Male ApoE~(-/-) mice were randomly assigned into a model group, a Buyang Huanwu Decoction group, an Astragali Radix-Angelicae Sinensis Radix combination group, and an atorvastatin group, and male C57BL/6J mice of the same weeks old were used as the control group. Other groups except the control group were given high-fat diets for 12 weeks to establish the AS model, and drugs were administrated by gavage. Aortic intimal hyperplasia thickness, blood lipid level, plasma inflammatory cytokine levels, M1/M2 macrophage markers, and expression levels of proteins in TLR4/MyD88/NF-κB pathway in the vessel wall were measured to evaluate the effects of drugs on AS lesions and inflammatory responses. The results showed that the AS model was successfully established with the ApoE~(-/-) mice fed with high-fat diets. Compared with the control group, the model group showed elevated plasma total cholesterol(TC), triglyceride(TG), and low-density lipoprotein cholesterol(LDL-c) levels(P<0.05), thickened intima(P<0.01), and increased plasma tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) levels(P<0.01). Moreover, the model group showed increased expression of vascular cell adhesion molecule-1(VCAM-1) and inducible nitric oxide synthase(iNOS)(P<0.01), inhibited expression of endothelial nitric oxide synthase(eNOS) and cluster of differentiation 206(CD206)(P<0.01), and up-regulated mRNA and protein levels of TLR4, MyD88, NF-κB inhibitor alpha(IκBα), and NF-κB in the vessel wall(P<0.05). Compared with the model group, Buyang Huanwu Decoction and Astragali Radix-Angelicae Sinensis Radix combination lowered the plasma TC and LDL-c levels(P<0.01), alleviated the intimal hyperplasia(P<0.01), and reduced the plasma TNF-α and IL-6 levels(P<0.05). Moreover, the two interventions promoted the expression of eNOS and CD206(P<0.05), inhibited the expression of VCAM-1 and iNOS(P<0.01), and down-regulated the mRNA and protein levels of TLR4, MyD88, IκBα, and NF-κB(P<0.05) in the vessel wall. This study indicated that Buyang Huanwu Decoction and Astragali Radix-Angelicae Sinensis Radix combination could delay the progression of AS, inhibit the polarization of vascular wall macrophages toward M1 type, and attenuate vascular inflammatory response by inhibiting the activation of TLR4/MyD88/NF-κB signaling pathway in the vascular wall. Astragali Radix and Angelicae Sinensis Radix were the main pharmacological substances in Buyang Huanwu Decoction for alleviating the AS vascular inflammatory response.

Downregulated Acetyl-CoA Acyltransferase 2 Promoted the Progression of Hepatocellular Carcinoma and Participated in the Formation of Immunosuppressive Microenvironment.

The aim of this study is to explore the role of acetyl-CoA acyltransferase 2 (ACAA2) in the progression of hepatocellular carcinoma (HCC). Bulk RNA data and single-cell RNA data were acquired from The Cancer Genome Atlas and Gene Expression Omnibus. Both in vitro and in vivo studies were used to determine the effect of ACAA2 on the progression of HCC, and RNA sequencing analysis was performed to explore the mechanism. We found downregulation of ACAA2 was involved in the malignant progression of HCC. The patient with low ACAA2 level had an immunosuppressive microenvironment in the HCC and predicted to have a poor prognosis. Decreased ACAA2 facilitated HCC proliferation and metastasis by activating the nuclear factor-κB (NFκB) signaling pathway. And increased CXCL1 induced by NFκB signaling pathway might be responsible for low level of ACAA2 related immunosuppressive microenvironment. Furthermore, the expression of ACAA2 was also detected in immune cells. The expression of ACAA2 in CD4+TCF7+T, CD4+FOXP3+T, CD8+GZMK+T, and CD8+KLRD1+T cells was inversely correlated with the composition of CD8+PDCD1+T cells in HCC. This effect might be due to the CCL5-CCRs and HLA-E-KLRCs ligand-receptor networks. In a conclusion, downregulated ACAA2 promoted the progression of hepatocellular carcinoma and might be participated in the formation of immunosuppressive microenvironment. ACAA2 could be served as a favorable indicator for the prognosis of HCC and an ideal biomarker for immunotherapy.

Probiotics Improve Cognitive Impairment by Decreasing Bacteria-Related Pattern Recognition Receptor-Mediated Inflammation in the Gut-Brain Axis of Mice.

Some studies have found that probiotics can improve cognitive impairment in Alzheimer's disease, although the specific molecular mechanism by which this occurs has not been reported. Our previous research found that probiotics inhibited bacteria-related Toll-like receptor 4- and retinoic-acid-inducible gene-I-mediated nuclear factor-κB signaling pathways to improve cognitive impairment. However, it is unclear whether probiotics have similar effects on other pattern recognition receptors that respond to bacteria. Nine-month-old senescence-accelerated mouse prone 8 (SAMP8) mice received ProBiotic-4 (a mixture of Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus casei, and Bifidobacterium lactis) orally for 12 weeks. The effects on other bacteria-related pattern recognition receptors were then investigated. ProBiotic-4-treated SAMP8 mice showed improvement in memory deficits, synaptic and cerebral neuronal injuries, and microglial activation. ProBiotic-4 also markedly increased the expression of intestinal tight junction proteins (i.e., claudin-1, occludin, and zonula occluden-1), decreased the expression of interleukin-1β at both the mRNA and protein levels, and reduced the expression of caspase-11, cleaved caspase-1, and α-kinase 1 (ALPK1) in the intestine and brain. These findings suggest that probiotics may have therapeutic potential for the treatment of inflammation in the gut-brain axis and for cognitive impairment. The mechanism of action of probiotics appears to be related to inhibition of the caspase-11/caspase-1 pathway and reduction of ALPK1 expression.

Whey protein powder with milk fat globule membrane attenuates Alzheimer's disease pathology in 3×Tg-AD mice by modulating neuroinflammation through the peroxisome proliferator-activated receptor γ signaling pathway

Whey protein powder (PP), which is mainly derived from bovine milk, is rich in milk fat globule membrane (MFGM). The MGFM has been shown to play a role in promoting neuronal development and cognition in the infant brain. However, its role in Alzheimer's disease (AD) has not been elucidated. Here, we showed that the cognitive ability of 3×Tg-AD mice (a triple-transgenic mouse model of AD) could be improved by feeding PP to mice for 3 mo. In addition, PP ameliorated amyloid peptide deposition and tau hyperphosphorylation in the brains of AD mice. We found that PP could alleviate AD pathology by inhibiting neuroinflammation through the peroxisome proliferator-activated receptor γ (PPARγ)-nuclear factor-κB signaling pathway in the brains of AD mice. Our study revealed an unexpected role of PP in regulating the neuroinflammatory pathology of AD in a mouse model.

Novel pterostilbene derivatives ameliorate heart failure by reducing oxidative stress and inflammation through regulating Nrf2/NF-κB signaling pathway

Pterostilbene is a demethylated resveratrol derivative with attractive anti-inflammatory, anti-tumor and anti-oxidative stress activities. However, the clinical use of pterostilbene is limited by its poor selectivity and druggability. Heart failure is a leading cause of morbidity and mortality worldwide, which is closely related to enhanced oxidative stress and inflammation. There is an urgent need for new effective therapeutic drugs that can reduce oxidative stress and inflammatory responses. Therefore, we designed and synthesized a series of novel pterostilbene chalcone and dihydropyrazole derivatives with antioxidant and anti-inflammatory activities by the molecular hybridization strategy. The preliminary anti-inflammatory activities and structure-activity relationships of these compounds were evaluated by nitric oxide (NO) inhibitory activity in lipopolysaccharide (LPS)-treated RAW264.7 cells, and compound E1 exhibited the most potent anti-inflammatory activities. Furthermore, pretreatment with compound E1 decreased reactive oxygen species (ROS) generation both in RAW264.7 and H9C2 cells by increasing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), as well as downstream antioxidant enzymes superoxide dismutase 1 (SOD1), catalase (CAT) and glutathione peroxidase 1 (GPX1). In addition, compound E1 also significantly inhibited LPS or doxorubicin (DOX)-induced inflammation in both RAW264.7 and H9C2 cells through reducing the expression of inflammatory cytokines by inhibiting nuclear factor-κB (NF-κB) signaling pathway. Moreover, we found that compound E1 improved DOX-induced heart failure by inhibiting inflammation and oxidative stress in mouse model, which is mediated by the potential of antioxidant and anti-inflammatory activities. In conclusion, this study demonstrated the novel pterostilbene dihydropyrazole derivative E1 was identified as a promising agent for heart failure treatment.

Natural carrier-free self-assembled diterpene nanoparticles with its efficient anti-inflammation through the inhibition of NF-κB pathway for accelerated wound healing

Nanoscience has set off a wave in biomedicine to improve the performance of drugs in recent years, but additional materials are usually required for supramolecular nanoconstruction, undoubtedly increasing the health risks. Herein, we discovered a novel diterpene supramolecular self-assembly system without additional chemicals, Nepebracteatalic Acid nanoparticles (NA NPs), mediated through hydrogen bond, hydrophobic and electrostatic interaction. NA NPs performed sustained release behavior, lower expression levels for IL-6 and TNF-α than clinical anti-inflammatory drug Indometacin. Furthermore, the effect of NA NPs on the related protein p65 expression levels of nuclear factor-κB (NFκB) signaling pathway is quantified to confirm the enhanced anti-inflammatory property based on the self-assembly strategy. Meanwhile, the prepared nanoparticles have good biocompatibility which ensures outstanding inflammation inhibition, collagen deposition, angiogenesis during wound healing. This work opens up new prospects that carrier-free nanoparticles from NPMs have great potential to exert clinical application value, meanwhile providing reference for developing green nanoscience.

CRISPR/Cas9-mediated knockout of SLC15A4 gene involved in the immune response in bovine rumen epithelial cells

The objective of this study was to determine the role of SLC15A4 in the muramyl dipeptide (MDP)-mediated inflammatory response of bovine rumen epithelial cells (BRECs). First, changes in the mRNA expression of pro-inflammatory factor genes in BRECs following 10 μg mL–1 MDP treatments were examined. RT-qPCR results showed that the expression of pro-inflammatory factor (IL-1β, IL-6, and TNF-α) mRNAs were significantly increased under MDP stimulation (P<0.001). Moreover, SLC15A4-Knockout (SLC15A4-KO) cells were obtained through lentivirus packaging, transfection, screening, and cell monoclonal culture. In order to gain further insight into the potential function of SLC15A4, we utilized transcriptome data, which revealed a change in the genes between WT-BRECs and SLC15A4-KO. Five down-regulated pro-inflammatory genes and 13 down-regulated chemokine genes related to the inflammatory response were identified. Meanwhile, the down-regulated genes were mostly enriched in the nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. The results of RT-qPCR also verified these detected changes. To further determine the mechanism of how WT and SLC15A4-KO BRECs are involved in inflammatory responses, we investigated the inflammatory responses of cells exposed to MDP. WT-BRECs and SLC15A4-KO were treated with a culture medium containing 10 μg mL–1 MDP, in comparison to a control without MDP. Our results show that SLC15A4-KO BRECs had reduced the expression of genes (IL-6, TNF-α, CXCL2, CXCL3, CXCL9, and CCL2) and proteins (p-p65 and p-p44/42) from the MDP-mediated inflammatory response compared to WT-BRECs (P<0.05). In this experiment, CRISPR-Cas9 was used to KO the di/tripeptide transporter SLC15A4, and its role was confirmed via the MDP-induced inflammatory response in BRECs. This work will provide a theoretical basis for studying the pro-inflammatory mechanism of MDP and its application in the prevention and treatment of subacute rumen acidosis in dairy cows.

Iristectorigenin C suppresses LPS-induced macrophages activation by regulating mPGES-1 expression and p38/JNK pathway

Ethnopharmacological relevanceNonsteroidal anti-inflammatory drugs (NSAIDs) have been used clinically to treat inflammatory diseases clinically. However, the adverse effects of NSAIDs cannot be ignored. Therefore, it is critical for us to find alternative anti-inflammatory drugs that can reduce adverse reactions to herbal medicine, such as Iris tectorum Maxim., which has therapeutic effects and can treat inflammatory diseases and liver-related diseases. Aim of the studyThis study aimed to isolate active compounds from I. tectorum and investigate their anti-inflammatory effects and action mechanisms. Materials and methodsFourteen compounds were isolated from I. tectorum using silica gel column chromatography, Sephadex LH-20, ODS and high performance liquid chromatography, and their structures were identified by examining physicochemical properties, ultraviolet spectroscopy, infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. Classical inflammatory cell models were established using lipopolysaccharide (LPS)-stimulated RAW264.7 cells and rat primary peritoneal macrophages to examine the effect of these compounds. To examine the action mechanisms, the nitric oxide (NO) levels were measured by Griess reagent and the levels of inflammatory cytokines in the supernatant were measured by ELISA; The expressions of major proteins in prostaglandin E2 (PGE2) synthesis and the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways were examined by Western blotting, and the mRNA expression levels were measured by quantitative real-time polymerase chain reaction; and the nuclear translocation of p65 was examined by high content imaging. Molecular docking was used to predict the binding of active compound to target protein. ResultsOur findings revealed that Iristectorigenin C (IT24) significantly inhibited the levels of NO and PGE2 without affecting cyclooxygenase (COX)-1/COX-2 expression in LPS-induced RAW264.7 cells and rat peritoneal macrophages. Furthermore, IT24 was shown to decrease the expression of microsomal prostaglandin synthetase-1 (mPGES-1) in LPS-induced rat peritoneal macrophages. IT24 did not suppress the phosphorylation and nuclear translocation of proteins in the NF-κB pathway, but it inhibited the phosphorylation of p38/JNK in LPS-stimulated RAW264.7 cells. Additionally, molecular docking analysis indicated that IT24 may directly bind to the mPGES-1 protein. ConclusionIT24 might inhibit mPGES-1 and the p38/JNK pathway to exert its anti-inflammatory effects and could be also developed as an inhibitor of mPGES-1 to prevent and treat mPGES-1-related diseases, such as inflammatory diseases, and holds promise for further research and drug development.

Casein Kinase 2 Alpha Inhibition Protects against Sepsis-Induced Acute Kidney Injury.

Sepsis-induced acute kidney injury (AKI) is a common complication in critically ill patients, often resulting in high rates of morbidity and mortality. Previous studies have demonstrated the effectiveness of casein kinase 2 alpha (CK2α) inhibition in ameliorating ischemia-reperfusion-induced AKI. In this study, our aim was to investigate the potential of the selective CK2α inhibitor, 4,5,6,7-tetrabromobenzotriazole (TBBt), in the context of sepsis-induced AKI. To assess this, we initially confirmed an upregulation of CK2α expression following a cecum ligation and puncture (CLP) procedure in mice. Subsequently, TBBt was administered to a group of mice prior to CLP, and their outcomes were compared to those of sham mice. The results revealed that, following CLP, the mice exhibited typical sepsis-associated patterns of AKI, characterized by reduced renal function (evidenced by elevated blood urea nitrogen and creatinine levels), renal damage, and inflammation (indicated by increased tubular injury score, pro-inflammatory cytokine levels, and apoptosis index). However, mice treated with TBBt demonstrated fewer of these changes, and their renal function and architecture remained comparable to that of the sham mice. The anti-inflammatory and anti-apoptotic properties of TBBt are believed to be associated with the inactivation of the mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) signaling pathways. In conclusion, these findings suggest that inhibiting CK2α could be a promising therapeutic strategy for treating sepsis-induced AKI.

An inhibitor of claudin-5 interactions, M01, alleviates neuroinflammation and vasogenic edema after blood-spinal cord barrier dysfunction.

Molecular docking modeling has confirmed that M01 (C30H28N4O5) acts as a potent inhibitor of claudin-5. Our prior data indicated that claudin-5 is essential to the structural integrity of the blood-spinal cord barrier (BSCB). The aim of this study was to investigate the effect of M01 on the integrity of the BSCB and its effect on neuroinflammation and vasogenic edema after blood-spinal cord barrier dysfunction in in-vitro and in-vivo models. Transwell chambers were used to construct an in-vitro model of the BSCB. Fluorescein isothiocyanate (FITC)-dextran permeability and leakage assays were performed to validate the reliability of the BSCB model. Semiquantitative analysis of inflammatory factor expression and nuclear factor-κB signaling pathway protein levels was performed using western blotting. The transendothelial electrical resistance of each group was measured, and the expression of a tight junction protein ZO-1 was determined via immunofluorescence confocal microscopy. Rat models of spinal cord injury were established by the modified Allen's weight-drop method. Histological analysis was carried out by hematoxylin and eosin staining. Locomotor activity was evaluated with Footprint analysis and the Basso-Beattie-Bresnahan scoring system. The M01 (10 μM) reduced the release of inflammatory factors and degradation of ZO-1 and improved the integrity of the BSCB by reversing vasogenic edema and leakage. M01 may represent a new strategy for the treatment of diseases related to BSCB destruction.

Scoparone inhibits breast cancer cell viability through the NF‑κB signaling pathway.

Scoparone (SCO) is a compound found in the stems and leaves of Artemisia capillaris. The pharmacological uses of SCO include significant hypotensive, cholagogic, anti-inflammatory, analgesic, lipid-lowering, anti-asthmatic and anti-coagulant effects. The present study aimed to verify the anticancer potential of SCO in breast cancer (BC) cells and its underlying molecular mechanism. Cell Counting Kit-8 and flow cytometry were used to analyze the effects of SCO on cell viability and apoptosis. Nucleocytoplasmic separation was used to analyze the location of the long non-coding RNA (lncRNA) small nucleolar RNA host gene 12 (SNHG12) in BC cells. Reverse transcription-quantitative PCR was used to analyze the effect of SCO on the expression levels of SNHG12, microRNA (miRNA/miR)-140-3p and tumor necrosis factor receptor associated factor 2 (TRAF2). Western blotting was used to analyze the protein expression levels of TRAF2 and downstream nuclear factor κB (NF-κB) signaling pathways. The results demonstrated that SCO had a time- and dose-dependent inhibitory effect on the viability of BC cells, and that the upregulated lncRNA SNHG12 in BC cells was inhibited by SCO. SNHG12, which was primarily expressed in the cytoplasm, acted as a competing endogenous RNA, sponged miR-140-3p and inhibited the expression of miR-140-3p. The transcriptional activity and translational level of TRAF2, a downstream target of miR-140-3p, decreased following the SCO-mediated suppression of SNHG12 expression. As an upstream effector, TRAF2 activity reduction mediated the inhibition of NF-κB signaling, decreased the viability and migration of BC cells, and promoted BC cell apoptosis. In conclusion, SCO-induced inhibition of viability and promotion of apoptosis in BC cells are achieved through the inhibition of NF-κB signaling, which is associated with regulation of the SNHG12/miR-140-3p/TRAF2 axis. This understanding provides new drug candidates for the treatment of BC and a theoretical basis for biology.

Astragaloside IV attenuates high glucose-induced NF-κB-mediated inflammation through activation of PI3K/AKT-ERK-dependent Nrf2/ARE signaling pathway in glomerular mesangial cells.

Inflammation is a key contributor to diabetic kidney disease pathogenesis, including reactive oxidation stress (ROS)-mediated nuclear factor-κB (NF-κB) signaling pathway. In this study, we examined the effect of Astragaloside IV (AS-IV) on anti-inflammatory and anti-oxidative properties under high glucose (HG) condition and the potential mechanism in glomerular mesangial cells (GMCs). We showed that AS-IV concentration-dependently reduced GMCs proliferation, restrained ROS release and hydrogen peroxide content, and suppressed pro-inflammatory cytokines as well as pro-fibrotic factors expression, which were associated with the inhibition of NF-κB and nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling activation. Accordingly, both NF-κB overexpression by using RNA plasmid and Nrf2 gene silencing by using RNA interference weakened the ability of AS-IV to ameliorate HG-induced oxidative stress, inflammation, and cell proliferation. Furthermore, phosphatidylinositide 3-kinases (PI3K)/serine/threonine protein kinase (Akt) and extracellular regulated protein kinases (ERK) signaling pathway regulated the process of AS-IV-induced Nrf2 activation and antioxidant capacity, which evidenced by using PI3K inhibitor LY294002 or ERK inhibitor PD98059 that largely abolished the AS-IV efficacy. Taken together, these results indicated that AS-IV protected against HG-induced GMCs damage by inhibiting ROS/NF-kB-induced increases of inflammatory cytokines, fibrosis biomarkers, and cell proliferation via up-regulation of Nrf2-dependent antioxidant enzyme expression, which were mediated by PI3K/Akt and ERK signaling pathway activation.

Fermented Sargassum fusiforme Mitigates Ulcerative Colitis in Mice by Regulating the Intestinal Barrier, Oxidative Stress, and the NF-κB Pathway.

In recent years, Sargassum fusiforme has gained increasing attention for its ability to improve human health and reduce the risk of disease. Nevertheless, there have been few reports on the beneficial functions of fermented Sargassum fusiforme. In this study, the role of fermented Sargassum fusiforme in the mitigation of ulcerative colitis was investigated. Both fermented and unfermented Sargassum fusiforme demonstrated significant improvement in weight loss, diarrhea, bloody stools, and colon shortening in mice with acute colitis. Fermented Sargassum fusiforme further protected against goblet cell loss, decreased intestinal epithelium permeability, and enhanced the expression of tight junction proteins. Fermented Sargassum fusiforme reduced oxidative stress, which was demonstrated by a decrease in nitric oxide (NO), myeloperoxidase (MPO), and malondialdehyde (MDA) concentrations in the colon of mice and an increase in total superoxide dismutase (T-SOD) activity in the colon. Meanwhile, catalase (CAT) concentrations in both the colon and serum of mice were significantly increased. Fermented Sargassum fusiforme also attenuated the inflammatory response, which was evidenced by the decreased level of pro-inflammatory cytokines in the colon. Moreover, fermented Sargassum fusiforme inhibited the nuclear factor-κB (NF-κB) signaling pathway and increased the production of short-chain fatty acids in the intestine. These findings indicate that fermented Sargassum fusiforme may have the potential to be developed as an alternative strategy for alleviating colitis.

Overexpression of IκB⍺ modulates NF-κB activation of inflammatory target gene expression.

Cells respond to inflammatory stimuli such as cytokines by activation of the nuclear factor-κB (NF-κB) signalling pathway, resulting in oscillatory translocation of the transcription factor p65 between nucleus and cytoplasm in some cell types. We investigate the relationship between p65 and inhibitor-κB⍺ (IκBα) protein levels and dynamic properties of the system, and how this interaction impacts on the expression of key inflammatory genes. Using bacterial artificial chromosomes, we developed new cell models of IκB⍺-eGFP protein overexpression in a pseudo-native genomic context. We find that cells with high levels of the negative regulator IκBα remain responsive to inflammatory stimuli and maintain dynamics for both p65 and IκBα. In contrast, canonical target gene expression is dramatically reduced by overexpression of IκBα, but can be partially rescued by overexpression of p65. Treatment with leptomycin B to promote nuclear accumulation of IκB⍺ also suppresses canonical target gene expression, suggesting a mechanism in which nuclear IκB⍺ accumulation prevents productive p65 interaction with promoter binding sites. This causes reduced target promoter binding and gene transcription, which we validate by chromatin immunoprecipitation and in primary cells. Overall, we show how inflammatory gene transcription is modulated by the expression levels of both IκB⍺ and p65. This results in an anti-inflammatory effect on transcription, demonstrating a broad mechanism to modulate the strength of inflammatory response.

Anti-inflammatory Activity of Gegen Decoction and Its Modulatory Mechanism on the NF-κB and MAPK Signaling Pathways.

Gegen Decoction as anti-inflammatory medicine is used in clinic widespread, however the specific anti-inflammatory molecular mechanism of Gegen Decoction is still unclear. The purpose was to study the anti-inflammatory activity of Gegen Decoction in vivo and to research its anti-inflammatory molecular mechanism. The content of main essential components in Gegen Decoction were determined by HPLC method. The anti-inflammatory activity of Gegen Decoction was confirmed through in vivo animal experiments. Furthermore, RAW 264.7 cells were stimulated by lipopolysaccharides to induce inflammatory reaction, the modulatory effect of Gegen Decoction on the activation process of mitogen-activated protein kinases and nuclear factor-κB signaling pathways was investigated. The content of puerarin was the highest among all the index components. Gegen Decoction inhibited carrageenan-induced paw edema in rats and xylene-induced ear swelling in mice. Gegen Decoction had no obvious toxicity against RAW 264.7 cells at the concentrations of 10-40 mg/mL; significantly inhibited the release of nitric oxide, prostaglandin E2, tumor necrosis factor-α and interleukin-6; down-regulated the high expression of inflammatory proteins inducible nitric oxide synthase and cyclooxygenase-2. It inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs)/extracellular regulated protein kinases (ERK)/c-Jun N-terminal kinase (JNK), the degradation of nuclear factor-κB (NF-κB)/inhibitor of NF-κB-α (IκB-α) and the nuclear translocation of NF-κB/p65 into nucleus. Gegen Decoction exerts significant anti-inflammatory activity, mainly by blocking the activation of both MAPKs and NF-κB pathway.

Bergapten alleviates depression-like behavior by inhibiting cyclooxygenase 2 activity and NF-κB/MAPK signaling pathway in microglia

Major depressive disorder (MDD) is a common psychiatric disorder that severely affects human life and health. However, the pathological mechanism of MDD is unclear, and effective treatment strategies are urgently needed. Microglia-mediated neuroinflammation is closely associated with the pathophysiology of depression. Bergapten (BG) is a natural pharmaceutical monomer with anti-inflammatory effects; however, its role in neuroinflammation and depression remains unclear. In this study, we employed a lipopolysaccharide (LPS) injection-induced acute depression mouse model, and found that treatment with BG significantly alleviated LPS-induced depression-like behavior in mice. BG administration largely decreased the increase in microglial numbers and rescued the microglial morphological changes induced by LPS injection. Furthermore, transcriptomic changes revealed a protective role of BG in the hippocampus of mice. Mechanistically, we found that BG directly inhibited cyclooxygenase 2 (COX2) activity, and suppressed nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways in microglia. Together, these results highlight the important role of BG in microglial activation, neuroinflammation, and depression-like behavior, thus providing a new candidate drug for depression treatment.

Maresin1 ameliorates postoperative cognitive dysfunction in aged rats by potentially regulating the NF-κB pathway to inhibit astrocyte activation

Postoperative cognitive dysfunction (POCD) is one of the most serious postoperative complications in the elderly population. Perioperative central neuroinflammation is considered to be an important pathological mechanism of POCD, with the activation of astrocytes playing a key role in central neuroinflammation. Maresin1 (MaR1) is a specific pro-resolving mediator synthesized by macrophages in the resolution stage of inflammation, and provides unique anti-inflammatory and pro-resolution effects by limiting excessive neuroinflammation and promoting postoperative recovery. However, the question remains whether MaR1 can have a positive effect on POCD. The objective of this study was to investigate the protective effect of MaR1 on POCD cognitive function in aged rats after splenectomy. Morris water maze test and IntelliCage test showed that splenectomy could cause transient cognitive dysfunction in aged rats; however, the cognitive impairment of rats was significantly mitigated when MaR1 pretreatment was administered. MaR1 significantly alleviated the fluorescence intensity and protein expression of glial fibrillary acidic protein and central nervous system specific protein in the cornu ammonis 1 region of the hippocampus. Simultaneously, the morphology of astrocytes was also severely altered. Further experiments showed that MaR1 inhibited the mRNA and protein expression of several key proinflammatory cytokines–interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampus of aged rats following splenectomy. The molecular mechanism underlying this process was explored by evaluating expression of components of the nuclear factor κB (NF-κB) signaling pathway. MaR1 substantially inhibited the mRNA and protein expression of NF-κB p65 and κB inhibitor kinase β. Collectively, these results suggest that MaR1 ameliorated splenectomy-induced transient cognitive impairment in elderly rats, and this neuroprotective mechanism may occur through regulating the NF-κB pathway to inhibit astrocyte activation.

TIPE2 knockdown exacerbates isoflurane-induced postoperative cognitive impairment in mice by inducing activation of STAT3 and NF-κB signaling pathways.

Anesthetic exposure causes learning and memory impairment, the mechanisms of which remain unknown. It has been reported that tumor necrosis factor-α-inducer protein 8-like 2 (TIPE2) is a newly discovered immune negative regulator that is essential for maintaining immune homeostasis. This study aimed to examine the role of TIPE2 in isoflurane-induced postoperative cognitive decline (POCD). An AAV empty vector and AAV shTIPE2 vector for the knockdown of TIPE2 were injected into the dorsal hippocampus of mice. Mice were continuously exposed to 1.5% isoflurane followed by abdominal exploration. Behavioral tests including the open field test and fear conditioning test were performed on the third and fourth day post-operation. Apoptosis was detected by terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling staining. The kits were used to detect the activity of antioxidant enzymes. Inflammatory cytokine levels were detected by enzyme-linked immunosorbent assay. Signal transducer and activator of transcription 3 (STAT3) and nuclear factor-κB (NF-κB) signaling pathway activities were detected by western blotting. TIPE2 expression increased after isoflurane anesthesia and surgery. TIPE2 deficiency aggravated cognitive impairment in mice and further caused apoptosis and oxidative stress in hippocampal neurons. TIPE2 deficiency induced microglial activation and increased secretion of proinflammatory cytokines. In addition, TIPE2 deficiency promoted STAT3 and NF-κB signaling activation induced by isoflurane anesthesia and after surgery. TIPE2 may play a neuroprotective role in POCD by regulating STAT3 and NF-κB pathways.

Leucine Supplementation Alleviates Immune and Antioxidant Function Damage in Adult Rats Induced by Early Weaning

BackgroundEarly weaning (EW) can lead to stress and destroy intestinal integrity. Leucine has functional diversity in antioxidant, immune, and metabolic regulation. ObjectivesThis study aimed to explore the lifelong impact of EW on intestinal, immune, and antioxidant functions of adult rats and the role of leucine supplementation in the alleviation of the damage caused by EW. MethodsIn this 211-d study, 36 Sprague Dawley (SD) rat pups were divided into 3 groups: 21-d weaning normal group, 17-d EW group, and 17-d EW group with 2-mo leucine supplementation. The content of amino acids in serum, immune and antioxidant indexes, intestinal morphology, liver transcriptomics, messenger RNA (mRNA), and protein expression of signaling pathway were determined. ResultsEW reduced the protein expression level of secretory immunoglobulin A (IgA) and reduced glutathione (GSH) in the jejunum and increased the protein expression concentrations of IgA, IgM, and interleukin 17 (IL-17) in serum, and tumor necrosis factor α and IL-1β in the jejunum. The impairment by EW was activated via nuclear transcription factor κB (NF-κB) signal pathway. In terms of antioxidation, EW reduced the concentration of GSH in the jejunum. After leucine supplementation, the damage induced by EW was partially repaired. ConclusionsEW causes long-term damage to the intestinal barrier function, immunity, apoptosis factor, and antioxidant function in rats and leucine supplementation could alleviate the impairment, suggesting a possible approach to EW.