Ganglioside GM3 suppresses lipopolysaccharide-induced inflammatory responses in rAW 264.7 macrophage cells through NF-κB, AP-1, and MAPKs signaling

Transcriptional upregulation of MMP-9 gene under hyperglycemic conditions in AGS cells: Role of AP-1 transcription factor

Gastric cancer and diabetes are two complex and interrelated diseases having significant impact on global health. Hyperglycemic condition notably exacerbates cancer by promoting inflammation, angiogenesis, and metastasis. Elevated glucose levels can also upregulate the expression of specific matrix metalloproteinases (MMPs), especially MMP-9, which is associated with cancer cell migration and invasion. However, the molecular mechanism behind such upregulation remains unexplored. In the present study, we have identified the mechanism for hyperglycemia-induced transcriptional activation of MMP-9, in gastric adenocarcinoma (AGS) cells. Using various tools like luciferase-reporter assays with promoter deletion constructs, siRNAs, pharmacological inhibitors, and nuclear translocation experiments, we have identified that the transcriptional activation of MMP-9 under hyperglycemic conditions is predominantly governed by the MAPK pathway, via formation of the AP-1 heterodimer. The p65 NF-κB signaling pathway, although activated, plays no significant role in regulating hyperglycemia-induced MMP-9 expression. Chromatin immunoprecipitation studies indicate that the distal AP-1 binding site is responsible for hyperglycemia-induced MMP-9 transcription; whereas the proximal one accounts for both hyperglycemia-induced and basal MMP-9 transcription. Therefore, binding of AP-1 at both the proximal and distal binding sites on the MMP-9 promoter region is required for hyperglycemia-induced MMP-9 expression. Overall, our study unveils a novel mechanism of MMP-9 transcription under hyperglycemic conditions and also suggests that inhibiting the binding of the AP-1 heterodimer with its distal binding site can potentially reduce the complications developed during gastric cancer-hyperglycemia co-morbidity. A drug designed specifically to inhibit this interaction may prevent hyperglycemia-induced tumor aggressiveness to a considerable extent by impeding MMP-9 transcription.

Heat-Killed Latilactobacillus sakei CNSC001WB and Lactobacillus pentosus WB693 Have an Anti-inflammatory Effect on LPS-Stimulated RAW 264.7 Cells

Excessive inflammatory results, such as those seen in rheumatoid arthritis and cardiovascular diseases, are known to cause various complications. Therefore, we aimed to investigate whether heat-killed Latilactobacillus sakei CNS001WB and Lactobacillus pentosus WB693 can prevent inflammatory reactions. When LPS-stimulated RAW 264.7 cells were handled with either heat-killed Lact. sakei CNSC001WB or Lact. pentosus WB693, the production of nitric oxide reduced. Furthermore, the expression of cyclooxygenase (COX)-2 and proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6, was suppressed. The expression of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4), which play important roles in inflammatory diseases, especially arthritis, was also reduced. Moreover, these strains inhibited nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, which activate various cytokines and inflammatory mediators. Additionally, heat-killed Lact. sakei CNSC001WB and Lact. pentosus WB693 inhibited the reactive oxygen species (ROS) production. Based on these results, we concluded that heat-killed Lact. sakei CNSC001WB and Lact. pentosus WB693 sufficiently inhibited the inflammatory response and may have anti-inflammatory potential.

Bioactive sphingolipids as emerging targets for signal transduction in cancer development

Sphingolipids, crucial components of cellular membranes, play a vital role in maintaining cellular structure and signaling integrity. Disruptions in sphingolipid metabolism are increasingly implicated in cancer development. Key bioactive sphingolipids, such as ceramides, sphingosine-1-phosphate (S1P), ceramide-1-phosphate (C1P), and glycosphingolipids, profoundly impact tumor biology. They influence the behavior of tumor cells, stromal cells, and immune cells, affecting tumor aggressiveness, angiogenesis, immune modulation, and extracellular matrix remodeling. Furthermore, abnormal expression of sphingolipids and their metabolizing enzymes modulates the secretion of tumor-derived extracellular vesicles (TDEs), which are key players in creating an immunosuppressive tumor microenvironment, remodeling the extracellular matrix, and facilitating oncogenic signaling within in situ tumors and distant pre-metastatic niches (PMNs). Understanding the role of sphingolipids in the biogenesis of tumor-derived extracellular vesicles (TDEs) and their bioactive contents can pave the way for new biomarkers in cancer diagnosis and prognosis, ultimately enhancing comprehensive tumor treatment strategies.

The Antioxidant and Anti-Inflammatory Properties of Bee Pollen from Acorn (Quercus acutissima Carr.) and Darae (Actinidia arguta)

Aging is a complex biological process characterized by a progressive decline in physical function and an increased risk of age-related chronic diseases. Additionally, oxidative stress is known to cause severe tissue damage and inflammation. Pollens from acorn and darae are extensively produced in Korea. However, the underlying molecular mechanisms of these components under the conditions of inflammation and oxidative stress remain largely unknown. This study aimed to investigate the effect of bee pollen components on lipopolysaccharide (LPS)-induced RAW 264.7 mouse macrophages. This study demonstrates that acorn and darae significantly inhibit the LPS-induced production of inflammatory mediators, such as nitric oxide (NO) and prostaglandin E2 (PGE2), in RAW 264.7 cells. Specifically, bee pollen from acorn reduces NO production by 69.23 ± 0.04% and PGE2 production by 44.16 ± 0.08%, while bee pollen from darae decreases NO production by 78.21 ± 0.06% and PGE2 production by 66.23 ± 0.1%. Furthermore, bee pollen from acorn and darae reduced active oxygen species (ROS) production by 47.01 ± 0.5% and 60 ± 0.9%, respectively. It increased the nuclear potential of nuclear factor erythroid 2-related factor 2 (Nrf2) in LPS-stimulated RAW 264.7 cells. Moreover, treatment with acorn and darae abolished the nuclear potential of nuclear factor κB (NF-κB) and reduced the expression of extracellular signal-associated kinase (ERK) and c-Jun N-terminal kinase (JNK) phosphorylation in LPS-stimulated RAW 264.7 cells. Specifically, acorn decreased NF-κB nuclear potential by 90.01 ± 0.3%, ERK phosphorylation by 76.19 ± 1.1%, and JNK phosphorylation by 57.14 ± 1.2%. Similarly, darae reduced NF-κB nuclear potential by 92.21 ± 0.5%, ERK phosphorylation by 61.11 ± 0.8%, and JNK phosphorylation by 59.72 ± 1.12%. These results suggest that acorn and darae could be potential antioxidants and anti-inflammatory agents.

Anti-Inflammatory Therapeutic Mechanisms of Isothiocyanates: Insights from Sulforaphane

Isothiocyanates (ITCs) belong to a group of natural products that possess a highly reactive electrophilic -N=C=S functional group. They are stored in plants as precursor molecules, glucosinolates, which are processed by the tyrosinase enzyme upon plant tissue damage to release ITCs, along with other products. Isolated from broccoli, sulforaphane is by far the most studied antioxidant ITC, acting primarily through the induction of a transcription factor, the nuclear factor erythroid 2-related factor 2 (Nrf2), which upregulates downstream antioxidant genes/proteins. Paradoxically, sulforaphane, as a pro-oxidant compound, can also increase the levels of reactive oxygen species, a mechanism which is attributed to its anticancer effect. Beyond highlighting the common pro-oxidant and antioxidant effects of sulforaphane, the present paper was designed to assess the diverse anti-inflammatory mechanisms reported to date using a variety of in vitro and in vivo experimental models. Sulforaphane downregulates the expression of pro-inflammatory cytokines, chemokines, adhesion molecules, cycloxyhenase-2, and inducible nitric oxide synthase. The signalling pathways of nuclear factor κB, activator protein 1, sirtuins 1, silent information regulator sirtuin 1 and 3, and microRNAs are among those affected by sulforaphane. These anti-inflammatory actions are sometimes due to direct action via interaction with the sulfhydryl structural moiety of cysteine residues in enzymes/proteins. The following are among the topics discussed in this paper: paradoxical signalling pathways such as the immunosuppressant or immunostimulant mechanisms; crosstalk between the oxidative and inflammatory pathways; and effects dependent on health and disease states.

Anti-inflammatory activities of Levilactobacillus brevis KU15147 in RAW 264.7 cells stimulated with lipopolysaccharide on attenuating NF-κB, AP-1, and MAPK signaling pathways

Probiotics confer many beneficial effects on several illnesses, ranging from microbial diarrhea to inflammatory diseases. This study was conducted on whether Levilactobacillus brevis KU15147 obtained from kimchi has anti-inflammatory effects in RAW 264.7 cells stimulated with lipopolysaccharide (LPS) and antioxidant potential. L. brevis KU15147 reduced nitric oxide and prostaglandin E2 levels with decreasing the activation of inducible nitric oxide synthase and cyclooxygenase-2 without cell cytotoxicity. In addition, L. brevis KU15147 attenuated proinflammatory cytokine production including tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 in RAW 264.7 cells stimulated with LPS. Additionally, L. brevis KU15147 reduced the activity of nuclear factor-κB, activator protein-1, and mitogen-activated protein kinase signaling pathways. Furthermore, L. brevis KU15147 downregulated the production of reactive oxygen species. Therefore, L. brevis KU15147 was concluded that had an inhibition effect on LPS-induced inflammatory responses and can be used in functional foods to suppress inflammatory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01318-w.

Current state-of-the-art on ganglioside-mediated immune modulation in the tumor microenvironment

Gangliosides are sialylated glycolipids, mainly present at the cell surface membrane, involved in a variety of cellular signaling events. During malignant transformation, the composition of these glycosphingolipids is altered, leading to structural and functional changes, which are often negatively correlated to patient survival. Cancer cells have the ability to shed gangliosides into the tumor microenvironment, where they have a strong impact on anti-tumor immunity and promote tumor progression. Since most ganglioside species show prominent immunosuppressive activities, they might be considered checkpoint molecules released to counteract ongoing immunosurveillance. In this review, we highlight the current state-of-the-art on the ganglioside-mediated immunomodulation, specified for the different immune cells and individual gangliosides. In addition, we address the dual role that certain gangliosides play in the tumor microenvironment. Even though some ganglioside species have been more extensively studied than others, they are proven to contribute to the defense mechanisms of the tumor and should be regarded as promising therapeutic targets for inclusion in future immunotherapy regimens.

Ganglioside GM3 deficiency enhances mast cell sensitivity

Mast cells are a significant source of cytokines and chemokines that play a role in pathological processes. Gangliosides, which are complex lipids with a sugar chain, are present in all eukaryotic cell membranes and comprise lipid rafts. Ganglioside GM3, the first ganglioside in the synthetic pathway, is a common precursor of the specifying derivatives and is well known for its various functions in biosystems. Mast cells contain high levels of gangliosides; however, the involvement of GM3 in mast cell sensitivity is unclear. Therefore, in this study, we elucidated the role of ganglioside GM3 in mast cells and skin inflammation. GM3 synthase (GM3S)-deficient mast cells showed cytosolic granule topological changes and hyperactivation upon IgE-DNP stimulation without affecting proliferation and differentiation. Additionally, inflammatory cytokine levels increased in GM3S-deficient bone marrow-derived mast cells (BMMC). Furthermore, GM3S-KO mice and GM3S-KO BMMC transplantation showed increased skin allergic reactions. Besides mast cell hypersensitivity caused by GM3S deficiency, membrane integrity decreased and GM3 supplementation rescued this loss of membrane integrity. Additionally, GM3S deficiency increased the phosphorylation of p38 mitogen-activated protein kinase. These results suggest that GM3 increases membrane integrity, leading to the suppression of the p38 signalling pathway in BMMC and contributing to skin allergic reaction.

Phytochemical screening and in-vitro biological properties of unprocessed and household processed fenugreek (Trigonella foenum-graecum Linn.) seeds and leaves

The impact of household processes on fenugreek leaves and seeds has been analyzed for total phenolic (TP) and total flavonoid content (TF), and in-vitro biological activities such as antioxidant, antimicrobial, and anti-inflammatory properties. Processes included air-drying for leaves and germinating, soaking, and boiling for seeds. Air-dried fenugreek leaves (ADFL) had high TP (15.27 mg GAE g^-1 D.W.) and TF (7.71 mg QE g^-1 D.W.) (milligram quercetin equivalents per gram dry weight). The TP contents of unprocessed, germinated, soaked, and boiled seeds were 6.54, 5.60, 4.59, and 3.84 mg gallic acid equivalents per gram of dry weight (mg GAE g^-1 D.W.), respectively. The TF contents in unprocessed fenugreek seeds, germinated fenugreek seeds, soaked fenugreek seeds, and boiled fenugreek seeds (BFS) were 4.23, 2.11, 2.10, and 2.33 mg QE g^-1 D.W., respectively. Sixteen phenolic and nineteen flavonoid compounds has been identified using high-performance liquid chromatography. Antioxidant activity using 2,2-diphenyl-1-picrylhydrazil (DPPH^·), 2,2-azinobis (3-ethylbenothiazoline-6-sulfonic acid (ABTS^+·), and ferric reducing antioxidant power (FRAP^·) assays indicated that ADFL had the highest activity. Antimicrobial activity has been evaluated against each of the eight pathogenic bacterial and fungal strains. ADFL showed the strongest activity with minimum inhibitory concentrations values ranging from 0.03 to 1.06 and 0.04 to 1.18 mg ml^·1 against bacterial and fungal strains, respectively. Anti-inflammatory activity was evaluated in-vitro against RAW 264.7 macrophage cells using the nitric oxide (NO) assay. Results revealed that ADFL had the highest cytotoxicity and anti-inflammatory activity according to the NO assay. Household processes significantly reduced the in-vitro biological properties of processed seeds.

Cannabinoids Transmogrify Cancer Metabolic Phenotype via Epigenetic Reprogramming and a Novel CBD Biased G Protein-Coupled Receptor Signaling Platform

The concept of epigenetic reprogramming predicts long-term functional health effects. This reprogramming can be activated by exogenous or endogenous insults, leading to altered healthy and different disease states. The exogenous or endogenous changes that involve developing a roadmap of epigenetic networking, such as drug components on epigenetic imprinting and restoring epigenome patterns laid down during embryonic development, are paramount to establishing youthful cell type and health. This epigenetic landscape is considered one of the hallmarks of cancer. The initiation and progression of cancer are considered to involve epigenetic abnormalities and genetic alterations. Cancer epigenetics have shown extensive reprogramming of every component of the epigenetic machinery in cancer development, including DNA methylation, histone modifications, nucleosome positioning, non-coding RNAs, and microRNA expression. Endocannabinoids are natural lipid molecules whose levels are regulated by specific biosynthetic and degradative enzymes. They bind to and activate two primary cannabinoid receptors, type 1 (CB1) and type 2 (CB2), and together with their metabolizing enzymes, form the endocannabinoid system. This review focuses on the role of cannabinoid receptors CB1 and CB2 signaling in activating numerous receptor tyrosine kinases and Toll-like receptors in the induction of epigenetic landscape alterations in cancer cells, which might transmogrify cancer metabolism and epigenetic reprogramming to a metastatic phenotype. Strategies applied from conception could represent an innovative epigenetic target for preventing and treating human cancer. Here, we describe novel cannabinoid-biased G protein-coupled receptor signaling platforms (GPCR), highlighting putative future perspectives in this field.

Hydrogen gas alleviates lipopolysaccharide-induced acute lung injury and inflammatory response in mice

Background

Chronic inflammation and oxidant/antioxidant imbalance are two main pathological features associated with lipopolysaccharide (LPS)-induced acute lung injury (ALI). The following study investigated the protective role of hydrogen (H₂), a gaseous molecule without known toxicity, in LPS-induced lung injury in mice and explored its potential molecular mechanisms.

Methods

Mice were randomly divided into three groups: H₂ control group, LPS group, and LPS + H₂ group. The mice were euthanized at the indicated time points, and the specimens were collected. The 72 h survival rates, cytokines contents, pathological changes, expression of Toll-like receptor 4 (TLR4), and oxidative stress indicators were analyzed. Moreover, under different culture conditions, RAW 264.7 mouse macrophages were used to investigate the potential molecular mechanisms of H₂ in vitro. Cells were divided into the following groups: PBS group, LPS group, and LPS + H₂ group. The cell viability, intracellular ROS, cytokines, and expression of TLR4 and nuclear factor kappa-B (NF-κB) were observed.

Results

Hydrogen inhalation increased the survival rate to 80%, reduced LPS-induced lung damage, and decreased inflammatory cytokine release in LPS mice. Besides, H₂ showed remarked anti-oxidative activity to reduce the MDA and NO contents in the lung. In vitro data further indicated that H₂ down-regulates the levels of ROS, NO, TNF-α, IL-6, and IL-1β in LPS-stimulated macrophages and inhibits the expression of TLR4 and the activation of nuclear factor kappa-B (NF-κB).

Conclusion

Hydrogen gas alleviates lipopolysaccharide-induced acute lung injury and inflammatory response most probably through the TLR4-NF-κB pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12950-022-00314-x.

Phytochemical screening and in-vitro biological properties of unprocessed and household processed fenugreek (Trigonella foenum- graecum Linn.) seeds and leaves.. [DOI: 10.21203/rs.3.rs-1952713/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The impact of household processes on fenugreek leaves and seeds was analyzed for total phenolic (TP) and total flavonoid content (TF), and in-vitro biological activities such as antioxidant, antimicrobial, and anti-inflammatory properties. Processes included air-drying of leaves and germinating, soaking, and boiling of seeds. Air-dried fenugreek leaves (ADFL) had high TP (15.27 mg GAE/g D.W.) and TF (7.71 mg QE/g D.W.). The TF of unprocessed, germinated, soaked, and boiled seeds had 6.54, 5.60, 4.59, and 3.84 mg GAE/g D.W., respectively. The TF in UFS, GFS, SFS, and BFS were 4.23, 2.11, 2.10, and 2.33 mg QE/g D.W., respectively. Sixteen phenolic and nineteen flavonoid compounds were identified using the HPLC. Antioxidant activity using DPPH•, ABTS+•, and FRAP• assays indicated that ADFL had high activity. Antimicrobial activity was evaluated against each eight pathogenic bacterial and fungal strains. ADFL showed a strong activity with MIC values ranging from 0.03 to 1.06 and 0.04 to 1.18 mg ml− 1 against bacterial and fungal strains, respectively. Anti-inflammatory activity was evaluated in-vitro against RAW 264.7 macrophage cells using of NO assay. Results revealed that ADFL had the highest cytotoxicity and anti-inflammatory activity according to NO assay. Household processes significantly declined the in-vitro biological properties of processed seeds.

Anti-Inflammatory Effects of GM1 Ganglioside on Endotoxin-Induced Uveitis in Rats

Exogenous ganglioside GM1 has been reported to exert an immunomodulatory effect. We investigated the anti-inflammatory effect of GM1 ganglioside on endotoxin-induced uveitis (EIU) in rats and RAW 264.7 macrophages. Methods: EIU was induced in Lewis rats by administering a subcutaneous injection of lipopolysaccharide (LPS). GM1 was injected intraperitoneally for three consecutive days prior to the LPS injection. Twenty-four hours after the LPS injection, the integrity of the blood-aqueous barrier was evaluated by determining the protein concentration and number of infiltrating cells in the aqueous humor (AqH). Immunohistochemical and Western blot analyses of the iris-ciliary body (ICB) were performed to evaluate the effect of GM1 on the LPS-induced expression of cyclooxygenase-2 (COX-2) and intercellular adhesion molecule-1 (ICAM-1). The effect of GM1 on proinflammatory mediators and signaling cascades was examined in LPS-stimulated RAW 264.7 cells using Western blotting and immunofluorescence staining to further clarify the underlying anti-inflammatory mechanism. Results: GM1 significantly reduced the protein concentration and number of infiltrating cells in the AqH of rats with EIU. GM1 also decreased the LPS-induced expression of the ICAM-1 and COX-2 proteins in the ICB. In RAW 264.7 cells, GM1 inhibited the proinflammatory mediators induced by LPS, including inducible nitric oxide synthase (iNOS), COX-2, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), and this inhibitory effect was potentially mediated by suppressing transforming growth factor-β-activated kinase 1 (TAK1) and reactive oxygen species (ROS)-mediated activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). Conclusions: Based on this study, GM1 may be a potential anti-inflammatory agent for ocular inflammatory diseases.

Targeted lipidomics reveals associations between serum sphingolipids and insulin sensitivity measured by the hyperinsulinemic-euglycemic clamp

AIMS

Sphingolipids(SPs) and their substrates and constituents, fatty acids (FAs), are implicated in the pathogenesis of various metabolic diseases associated. This study aimed to systematically investigate the associations between serum sphingolipids and insulin sensitivity as well as insulin secretion.

METHODS

We conducted a lipidomics evaluation of molecularly distinct SPs in the serum of 86 consecutive Chinese adults using LC/MS. The glucose infusion rate over 30 min (GIR₃₀) was measured under steady conditions to assess insulin sensitivity by the gold standard hyperinsulinemic-euglycemic clamp. We created the ROC curves to detect the serum SMs diagnostic value.

RESULTS

Total and subspecies of serum SMs and globotriaosyl ceramides (Gb3s) were positively related to GIR₃₀, free FAs (FFA 16:1, FFA20:4), some long chain GM3 and complex ceramide GluCers showed strong negative correlations with GIR₃₀. Notably, ROC curves showed that SM/Cer and SM d18:0/26:0 may be good serum lipid predictors of diagnostic indicators of insulin sensitivity close to conventional clinical indexes such as 1/HOMA-IR (areas under the curve > 0.80) based on GIR₃₀ as standard diagnostic criteria, and (SM/Cer)/(BMI*LDLc) areas under the curve = 0.93) is the best.

CONCLUSIONS

These results provide novel associations between serum sphingolipid between insulin sensitivity measured by the hyperinsulinemic-euglycemic clamp and identify two specific SPs that may represent prognostic biomarkers for insulin sensitivity.

Inhibitory effect of cathepsin K inhibitor (ODN-MK-0822) on invasion, migration and adhesion of human breast cancer cells in vitro

Approximately 90% of patients with advanced breast cancer develop bone metastases; an event that results in severe decrease of quality of life and a drastic deterioration in prognosis. Therefore, to increase the survival of breast cancer patients, the development of new therapeutic strategies to impair metastatic process and skeletal complications is critical. Previous studies on the role of cathepsin K (CTSK) in metastatic spreading led to several strategies for inhibition of this molecule such as MIV-711 (Medivir), balicatib and odanacatib (ODN) which were on trial in the past. The present study intended to assess the anti-metastatic efficacy of ODN in breast cancer cells. Human breast cancer cell lines MDA-MB-231 were treated with different concentrations of ODN and performed invasion, adhesion and migration assays and, RT-PCR and western blot to evaluate the effect of ODN on the metastatic potential of breast cancer cells. ODN markedly decreased wound healing cell migration, invasion and adhesion at a dose dependent manner. ODN inhibits cell invasion by decreasing the matrix metalloproteinase (MMP-9) with the upregulation of TIMP-1 expression. ODN effectively inhibited the phosphorylation of extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal Kinase (JNK), and blocked the expression of β-integrins and FAK proteins. ODN also significantly inhibited PI3K downstream targets Rac1, Cdc42, paxillin and Src which are critical for cell adhesion, migration and cytoskeletal reorganization. ODN exerts anti-metastatic action through inhibition of signaling pathway for MMP-9, PI3K and MAPK. This indicates potential therapeutic effects of ODN in the treatment of metastatic breast cancer.

2,4-Dihydroxyphenyl-benzo[d]thiazole (MHY553), a synthetic PPARα agonist, decreases age-associated inflammatory responses through PPARα activation and RS scavenging in the skin

We previously reported that 2,4-dihydroxyphenyl-benzo[d]thiazole (MHY553) is a PPARα agonist, which has been shown to inhibit tyrosinase activity in murine melanocyte and alleviate hepatic steatosis in aged rats. This study investigated the effects of MHY553 on the age-related occurrence of inflammatory responses via the molecular modulation of the nuclear factor-κB (NF-κB) signaling pathway in the skin of aged rats and skin fibroblast cells. Moreover, we investigated the antioxidant effect of MHY553 via in vitro assays of reactive oxygen species (ROS) and peroxynitrite (ONOO^-) scavenging activities. We also scrutinized the ability of MHY553 as a PPARα activator in aged rat skin and H₂O₂-induced Hs27 fibroblast cells. In vivo experiments were performed in young, aged, and MHY553-fed aged rats (3 mg or 5 mg∙kg ^-1∙day ^-1 for 4 weeks). MHY553 dose-dependently scavenged ROS and ONOO^-. Furthermore, we found that MHY553 suppressed the NF-κB transcription factor and downregulated mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) signaling. MHY553 also inhibited the expression of pro-inflammatory cytokines including COX-2, iNOS, IL-1β, and IL-6. Our findings indicate the MHY553 scavenges ROS/reactive nitrogen species and inhibits inflammatory cytokines through PPARα activation in the skin. Thus, these results suggest that MHY553 may be of therapeutic interest for protecting skin from oxidative stress-induced damage and intrinsic aging.

Hp-s1 Ganglioside Suppresses Proinflammatory Responses by Inhibiting MyD88-Dependent NF-κB and JNK/p38 MAPK Pathways in Lipopolysaccharide-Stimulated Microglial Cells

Hp-s1 ganglioside is isolated from the sperm of sea urchin (Hemicentrotus pulcherrimus). In addition to neuritogenic activity, the biological function of Hp-s1 in neuroinflammation is unknown. In this study, we investigated the anti-neuroinflammatory effect of Hp-s1 on lipopolysaccharide (LPS)-stimulated microglial cells. MG6 microglial cells were stimulated with LPS in the presence or absence of different Hp-s1 concentrations. The anti-inflammatory effect and underlying mechanism of Hp-s1 in LPS-activated microglia cells were assessed through a Cell Counting kit-8 assay, Western blot analysis, and immunofluorescence. We found that Hp-s1 suppressed not only the expression of inducible nitric oxide synthase and cyclooxygenase-2 but also the expression of proinflammatory cytokines, such as TNF-α, IL-1β, and IL-6. Hp-s1 inhibited the LPS-induced NF-κB signaling pathway by attenuating the phosphorylation and translocation of NF-κB p65 and by disrupting the degradation and phosphorylation of inhibitor κB-α (IκBα). Moreover, Hp-s1 inhibited the LPS-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Hp-s1 also reduced the expression of myeloid differentiation factor 88 (MyD88) and TNF receptor-associated factors 6 (TRAF6), which are prerequisites for NF-κB and MAPKs activation. These findings indicated that Hp-s1 alleviated LPS-induced proinflammatory responses in microglial cells by downregulating MyD88-mediated NF-κB and JNK/p38 MAPK signaling pathways, suggesting further evaluation as a new anti-neuroinflammatory drug.

Atraric Acid Exhibits Anti-Inflammatory Effect in Lipopolysaccharide-Stimulated RAW264.7 Cells and Mouse Models

Lichens, composite organisms resulting from the symbiotic association between the fungi and algae, produce a variety of secondary metabolites that exhibit pharmacological activities. This study aimed to investigate the anti-inflammatory activities of the secondary metabolite atraric acid produced by Heterodermia hypoleuca. The results confirmed that atraric acid could regulate induced pro-inflammatory cytokine, nitric oxide, prostaglandin E2, induced nitric oxide synthase and cyclooxygenase-2 enzyme expression in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Meanwhile, atraric acid downregulated the expression of phosphorylated IκB, extracellular signal-regulated kinases (ERK) and nuclear factor kappa B (NFκB) signaling pathway to exhibit anti-inflammatory effects in LPS-stimulated RAW264.7 cells. Based on these results, the anti-inflammatory effect of atraric acid during LPS-induced endotoxin shock in a mouse model was confirmed. In the atraric acid treated-group, cytokine production was decreased in the peritoneum and serum, and each organ damaged by LPS-stimulation was recovered. These results indicate that atraric acid has an anti-inflammatory effect, which may be the underlying molecular mechanism involved in the inactivation of the ERK/NFκB signaling pathway, demonstrating its potential therapeutic value for treating inflammatory diseases.

Current Research Landscape of Marine-Derived Anti-Atherosclerotic Substances

Atherosclerosis is a chronic disease characterized by lipid accumulation and chronic inflammation of the arterial wall, which is the pathological basis for coronary heart disease, cerebrovascular disease and thromboembolic disease. Currently, there is a lack of low-cost therapeutic agents that effectively slow the progression of atherosclerosis. Therefore, the development of new drugs is urgently needed. The research and development of marine-derived drugs have gained increasing interest from researchers across the world. Many marine organisms provide a rich material basis for the development of atherosclerotic drugs. This review focuses on the latest technological advances in the structures and mechanisms of action of marine-derived anti-atherosclerotic substances and the challenges of the application of these substances including marine polysaccharides, proteins and peptides, polyunsaturated fatty acids and small molecule compounds. Here, we describe the theoretical basis of marine biological resources in the treatment of atherosclerosis.

Anti-Inflammatory and Antioxidant Effects of Carpesium cernuum L. Methanolic Extract in LPS-Stimulated RAW 264.7 Macrophages

A hypernomic reaction or an abnormal inflammatory process could cause a series of diseases, such as cardiovascular disease, neurodegeneration, and cancer. Additionally, oxidative stress has been identified to induce severe tissue injury and inflammation. Carpesium cernuum L. (C. cernuum) is a Chinese folk medicine used for its anti-inflammatory, analgesic, and detoxifying properties. However, the underlying molecular mechanism of C. cernuum in inflammatory and oxidative stress conditions remains largely unknown. The aim of this study was to examine the effects of a methanolic extract of C. cernuum (CLME) on lipopolysaccharide- (LPS-) induced RAW 264.7 mouse macrophages and a sepsis mouse model. The data presented in this study indicated that CLME inhibited LPS-induced production of proinflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ (PGE₂) in RAW 264.7 cells. CLME treatment also reduced reactive oxygen species (ROS) generation and enhanced the expression of heme oxygenase-1 (HO-1) protein in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells. Moreover, CLME treatment abolished the nuclear translocation of nuclear factor-κB (NF-κB), enhanced the activation of nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), and reduced the expression of extracellular signal-related kinase (ERK) and ERK kinase (MEK) phosphorylation in LPS-stimulated RAW 264.7 cells. These outcomes implied that CLME could be a potential antioxidant and anti-inflammatory agent.

Gangliosides and Neuroblastomas

The focus of this review is the ganglio-series of glycosphingolipids found in neuroblastoma (NB) and the myriad of unanswered questions associated with their possible role(s) in this cancer. NB is one of the more common solid malignancies of children. Five-year survival for those diagnosed with low risk NB is 90-95%, while that for children with high-risk NB is around 40-50%. Much of the survival rate reflects age of diagnosis with children under a year having a much better prognosis than those over two. Identification of expression of GD2 on the surface of most NB cells led to studies of the effectiveness and subsequent approval of anti-GD2 antibodies as a treatment modality. Despite much success, a subset of patients, possibly those whose tumors fail to express concentrations of gangliosides such as GD1b and GT1b found in tumors from patients with a good prognosis, have tumors refractory to treatment. These observations support discussion of what is known about control of ganglioside synthesis, and their actual functions in NB, as well as their possible relationship to treatment response.

Wogonoside inhibits inflammatory cytokine production in lipopolysaccharide-stimulated macrophage by suppressing the activation of the JNK/c-Jun signaling pathway

Background

Mediated by innate immune cells, inflammation is an underlying presence in the pathogenesis of numerous pulmonary diseases. Macrophages play a critical role in mediating the initial response to infection in the lungs. When there is excessive activation of macrophages, hyper-production of inflammatory factors occurs, with inflammation as the ultimate result. Wogonoside, a bioactive flavonoid glycoside, has been reported to alleviate pulmonary inflammation. However, the mechanism underlying the anti-inflammatory effect of wogonoside has not yet been clarified.

Methods

The productions of nitric oxide (NO) and reactive oxygen species (ROS) were determined using a Griess reagent kit and a DAF-FM DA fluorescent probe, respectively. Moreover, the mRNA levels of inflammatory factors were quantified by qPCR, and the binding ability of c-Jun to promoters of inflammatory factors was performed by ChIP assay. Western blot was employed to detect the protein expression of inflammatory factors and signaling pathway.

Results

In this study, we found that pre-treatment with wogonoside dramatically suppressed lipopolysaccharide (LPS)-induced increase in the protein and mRNA levels of inflammatory factors in macrophages, such as cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and IL-6. Furthermore, wogonoside profoundly reduced the increase in NO and ROS production and significantly blocked phosphorylation of JNK in LPS-stimulated macrophages. As revealed by Western blot and qPCR analysis, wogonoside mediated the JNK-dependent inhibitory effect. Compared with wogonoside alone, a combination of wogonoside and JNK inhibitor SP600125 provided no extra benefit in suppressing the protein expression and mRNA levels of inflammatory factors in LPS-stimulated macrophages. Additionally, ChIP analysis demonstrated wogonoside to remarkably reduce c-Jun enrichment in COX-2, iNOS, IL-1β, TNF-α, and IL-6 promoters.

Conclusions

Collectively, our findings showed that wogonoside notably suppresses LPS-stimulated production of inflammatory factors by repressing the activation of the JNK/c-Jun signaling pathway in macrophages. This suggests that wogonoside could serve as a promising therapeutic agent for pulmonary diseases related to macrophage inflammation.

Ganglioside Synthesis by Plasma Membrane-Associated Sialyltransferase in Macrophages

Gangliosides are constituents of the mammalian cell membranes and participate in the inflammatory response. However, little is known about the presence and enzymatic activity of ganglioside sialyltransferases at the cell surface of macrophages, one of the most important immune cells involved in the innate inflammatory process. In the present study, using biochemical and fluorescent microscopy approaches, we found that endogenous ST8Sia-I is present at the plasma membrane (ecto-ST8Sia-I) of murine macrophage RAW264.7 cells. Moreover, ecto-ST8Sia-I can synthetize GD3 ganglioside at the cell surface in lipopolysaccharide (LPS)-stimulated macrophages even when LPS-stimulated macrophages reduced the total ST8Sia-I expression levels. Besides, cotreatment of LPS with an inhibitor of nitric oxide (NO) synthase recovered the ecto-ST8Sia-I expression, suggesting that NO production is involved in the reduction of ST8Sia-I expression. The diminution of ST8Sia-I expression in LPS-stimulated macrophages correlated with a reduction of GD3 and GM1 gangliosides and with an increment of GD1a. Taken together, the data supports the presence and activity of sialyltransferases at the plasma membrane of RAW264.7 cells. The variations of ecto-ST8Sia-I and ganglioside levels in stimulated macrophages constitutes a promissory pathway to further explore the physiological role of this and others ganglioside metabolism-related enzymes at the cell surface during the immune response.

Exogenous GM3 ganglioside inhibits atherosclerosis via multiple steps: A potential atheroprotective drug

Atherosclerosis is one of the leading causes of morbidity and mortality worldwide. A significant increase in ganglioside GM3 content generally happens in atherosclerotic plaques causing a GM3-enriched microenvironment. It remains unclear whether the GM3-enriched microenvironment influences atherogenesis. This study sought to answer the question by investigating exogenous GM3 effects on multiple steps involved in atherogenesis. First, the physicochemical properties of native low-density lipoprotein (LDL) and LDL enriched with exogenous GM3 (GM3-LDL) were characterized by dynamic laser scattering, atomic force microscopy, and agarose gel electrophoresis. Then, electrophoretic mobility, conjugated diene and malondialdehyde production, and amino group blockage of GM3-LDL/LDL were measured to determine LDL oxidation degrees and cellular recognition/internalization of GM3-LDL/GM3-oxLDL were detected via confocal microscopy and flow cytometry. Subsequently, influences of exogenous GM3 addition on the monocyte-adhering ability of endothelial cells and on lipid deposition in macrophages were investigated. Finally, exogenous GM3 effect on atherogenesis was evaluated using apoE^-/- mice fed a high-fat diet. We found that exogenous GM3 addition increased the size, charge, and stability of LDL particles, reduced LDL susceptibility to oxidation and its cellular recognition/internalization, impaired the monocyte-adhering ability of endothelial cells and lipid deposition in macrophages. Moreover, exogenous GM3 treatment also significantly decreased blood lipid levels and atherosclerotic lesion areas in atherosclerotic mice. The data imply that exogenous GM3 had an inhibitory effect on atherogenesis, suggesting a protective role of a GM3-enriched microenvironment in atherosclerotic plaques and implying a possibility of exogenous GM3 as an anti-atherosclerotic drug.

Analysis of a lectin microarray identifies altered sialylation of mouse serum glycoproteins induced by whole-body radiation exposure

Microarrays containing 45 different lectins were analyzed to identify global changes in the glycosylation of serum glycoproteins from mice exposed to whole-body γ-radiation. The results showed that radiation exposure increased and decreased the relative amounts of α-2,3- and α-2,6-sialic acids, respectively. The expression of α-2,3- and α-2,6-sialyltransferase genes in the liver was analyzed to determine whether changes in their expression were responsible for the sialic acid changes. The increase in α-2,3-sialic acid correlated with St3gal5 upregulation after radiation exposure; however, a decrease in St6gal1 expression was not observed. Analysis of a PCR array of genes expressed in irradiated mouse livers revealed that irradiation did not alter the expression of most of the included genes. These results suggest that glycomic screening of serum glycoproteins using lectin microarrays can be a powerful tool for identifying radiation-induced changes in the post-translational addition of sugar moieties to proteins. In addition, the results indicate that altered sialylation of glycoproteins may be an initial response to acute radiation exposure.

Esculentoside B inhibits inflammatory response through JNK and downstream NF-κB signaling pathway in LPS-triggered murine macrophage RAW 264.7 cells

Natural compound esculentoside B (EsB), (2S,4aR,6aR,6aS,6bR,8aR,9R,10R,11S,12aR,14bS)-11-hydroxy-9-(hydroxymethyl)-2 methoxycarbonyl-2,6a,6b,9,12a-pentamethyl-10-[(2S,3R,4S,5R)-3,4,5-trihydroxyoxan-2-yl]oxy-1,3,4,5,6,6a,7,8,8a,10,11,12,13,14b-tetradecahydropicene-4a-carboxylic acid with molecular weight of 664.833, isolated from roots of Phytolacca acinosa Roxb has been widely used as a constituent of traditional Chinese medicine (TCM). However, the anti-inflammatory capacity of EsB has not been reported yet. Therefore, the objective of this study was to investigate anti-inflammatory activities of EsB in LPS-treated macrophage RAW 264.7 cells. EsB could inhibit nitric oxide (NO) production. EsB also suppressed gene and protein expression levels of inducible isoform of NO synthase (NOS) and cyclooxygenase-2 in a dose-dependent manner. In addition, EsB decreased gene expression and protein secretion levels of pro-inflammatory cytokines such as IL-1β, TNF-α, and IL-6. EsB remarkably suppressed nuclear translocation of nuclear factor kappa-B (NF-κB) from cytosolic space. Phosphorylation of IκB was also inhibited by EsB. Moreover, EsB specifically down-regulated phospho-c-Jun N-terminal kinase (p-JNK), but not p-p38 or phospho-extracellular signal-regulated kinase 1/2 (p-ERK1/2). Taken together, these results suggest that EsB has inhibitory effect on inflammatory response by inactivating NF-κB and p-JNK. It could be used as a new modulatory drug for effective treatment of inflammation-related diseases.

Association of NF-κB and AP-1 with MMP-9 Overexpression in 2-Chloroethanol Exposed Rat Astrocytes

Subacute poisoning of 1,2-dichloroethane (1,2-DCE) has become a serious occupational problem in China, and brain edema is its main pathological consequence, but little is known about the underlying mechanisms. As the metabolite of 1,2-DCE, 2-chloroethanol (2-CE) is more reactive, and might play an important role in the toxic effects of 1,2-DCE. In our previous studies, we found that matrix metalloproteinases-9 (MMP-9) expression was enhanced in mouse brains upon treatment with 1,2-DCE, and in rat astrocytes exposed to 2-CE. In the present study, we analyzed the association of nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1) with MMP-9 overexpression in astrocytes treated with 2-CE. MMP-9, p65, c-Jun, and c-Fos were significantly upregulated by 2-CE treatment, which also enhanced phosphorylation of c-Jun, c-Fos and inhibitor of κBα (IκBα), and nuclear translocation of p65. Furthermore, inhibition of IκBα phosphorylation and AP-1 activity with the specific inhibitors could attenuate MMP-9 overexpression in the cells. On the other hand, inhibition of p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway suppressed the activation of both NF-κB and AP-1 in 2-CE-treated astrocytes. In conclusion, MMP-9 overexpression induced by 2-CE in astrocytes could be mediated at least in part through the p38 signaling pathway via activation of both NF-κB and AP-1. This study might provide novel clues for clarifying the mechanisms underlying 1,2-DCE associated cerebral edema.