Protective effect of 7-O-succinyl macrolactin A against intestinal inflammation is mediated through PI3-kinase/Akt/mTOR and NF-κB signaling pathways

Bacteroides fragilis capsular polysaccharide A ameliorates ulcerative colitis in rat by recovering intestinal barrier integrity and restoring gut microbiota

Bacteroides fragilis (B. fragilis) is a Gram-negative, obligate anaerobic, commensal bacterium residing in the human gut and holds therapeutic potential for ulcerative colitis (UC). Previous studies have indicated that capsular polysaccharide A (PSA) of B. fragilis is a crucial component for its effectiveness, possessing various biological activities such as anti-inflammatory, anti-tumor, and immune-modulating effects. We previously isolated and characterized the B. fragilis strain ZY-312 from the feces of a healthy breastfed infant, and extracted its PSA, named TP2. In this study, we explored the impact of TP2 on colonic inflammation and delved into its potential mechanisms. Initially, we used 2,4,6-trinitrobenzenesulfonic acid (TNBS) to induce colitis in rats and found that TP2 treatment significantly ameliorated TNBS-induced weight loss, increased clinical scores, extensive ulcers, and intestinal epithelial damage in UC rats. Further analysis revealed that TP2 effectively restored the intestinal barrier integrity in UC rats by regulating the expression of Muc-2, tight junction proteins (ZO-1, occludin, claudin-1, and claudin-2), as well as apoptosis-related proteins Bcl-2, BAX, and Cleaved-Caspase-3. Additionally, TP2 suppressed the expression of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL23, while promoting the secretion of anti-inflammatory cytokines IL-10 and IL-22, thereby inhibiting the occurrence of inflammation. TP2 also downregulated the phosphorylation levels of AKT and PI3K, effectively inhibiting the abnormal activation of the PI3K/AKT signaling pathway. More interestingly, 16S rRNA sequencing results showed that TP2 restored the ecological imbalance of the rat intestinal microbiota, with an increase in beneficial bacteria such as Lactobacillus and Limosilactobacillus observed in the treatment group. In conclusion, TP2 through the regulation of intestinal barrier-related cells and proteins, inhibition of apoptosis, modulation of inflammation-related cytokine levels, and control of abnormal activation of the PI3K/AKT signaling pathway, restores intestinal barrier integrity. Additionally, by reshaping the ecological imbalance of the gut microbiota, TP2 ultimately alleviates ulcerative colitis in rats.

Depression Exacerbates Dextran Sulfate Sodium-Induced Colitis via IRF5-Mediated Macrophage Polarization

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) and concurrent depression are predisposed to severer disease activity and a worse prognosis. Macrophage polarization toward the M1 phenotype may contribute to the exacerbation of IBD with comorbid depression. Moreover, interferon regulatory factor 5 (IRF5) is involved in the pathogenesis of IBD. The aim of this study was to explore the role of IRF5 in macrophage polarization in the impact of depression upon colitis.

METHODS

Depressive-like behavior was induced by repeated forced swim stress. Colon length, disease activity index (DAI), colon morphology, histology, ultrastructure of epithelial barrier, lamina propria macrophage polarization, and expression of IRF5 were compared between DSS colitis rats with and without depressive-like behavior. IRF5 shRNA was constructed to affect the rat peritoneal macrophages polarization in vitro. After IRF5 shRNA lentivirus was introduced into colon by enema, the colitis severity, lamina propria macrophage polarization, and TNF-α, IL-1β, and IL-10 of colon tissues were measured.

RESULTS

The study found severer colonic inflammation in depressed versus non-depressed DSS-colitis rats. Depressed DSS-colitis rats exhibited smaller subepithelial macrophages size and reduced intracellular granule diversity compared with nondepressed DSS-colitis rats. Increased polarization toward the M1 phenotype, elevated expression of IRF5, and co-expression of IRF5 with CD86 were found in depressed versus nondepressed DSS-colitis rats. Lentivirus-mediated shRNA interference with IRF5 expression switched rat peritoneal macrophage polarization from the M1 to the M2 phenotype, downregulated TNF-α, IL-1β expression to a greater extent in depressed versus nondepressed colitis rats.

CONCLUSIONS

IRF5-mediated macrophage polarization may likely underlie the deterioration of DSS-induced colitis caused by depression.

Investigating Key Targets of Dajianzhong Decoction for Treating Crohn’s Disease Using Weighted Gene Co-Expression Network

Background: Crohn’s disease (CD) is an inflammatory bowel disease, cases of which have substantially increased in recent years. The classical formula Dajianzhong decoction (DD, Japanese: Daikenchuto) is often used to treat CD, but few studies have evaluated related therapeutic mechanisms. In this study, we investigated the potential targets and mechanisms of DD used for treating CD at the molecular level through the weighted gene co-expression network. Methods: The main chemical components of the three DD herbs (Zanthoxylum bungeanum Maxim., Zingiber officinale (Willd.) Rosc., and Ginseng Radix et Rhizoma) were searched for using the HERB database. The targets for each component were identified using the SwissTargetPrediction and HERB databases, whereas the disease targets for CD were retrieved from the GeneCards and DisGeNET databases. The functional enrichment analysis was performed on the common targets of DD and CD. High-throughput sequencing data for CD patients were retrieved from the Gene Expression Omnibus database, and WGCNA was performed to identify the key targets. The association between the key targets and DD ingredients was verified using molecular docking. Results: By analyzing the interaction targets between DD and CD, 196 overlapping genes were identified. The enrichment results indicated that the PI3K-AKT, TNF, MAPK, and IL-17 signaling pathways influenced the mechanism of action of DD in counteracting CD. Combined with WGCNA, four differentially expressed genes (SLC6A4, NOS2, SHBG, and ABCB1) and their corresponding 24 compounds were closely related to the occurrence of CD. Conclusions: By integrating gene co-expression network analysis, this study preliminarily reveals the internal molecular mechanism of DD in treating CD from a systematic perspective, validated by molecular docking. However, these findings require further validation.

miRNA let-7 family regulated by NEAT1 and ARID3A/NF-κB inhibits PRRSV-2 replication in vitro and in vivo

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically devastating diseases affecting the swine industry worldwide. To investigate the role of miRNAs in the infection and susceptibility of PRRS virus (PRRSV), twenty-four miRNA libraries were constructed and sequenced from PRRSV-infected and mock-infected Porcine alveolar macrophages (PAMs) of Meishan, Landrace, Pietrain and Qingping pigs at 9 hours post infection (hpi), 36 hpi, and 60 hpi. The let-7 family miRNAs were significantly differentially expressed between PRRSV-infected and mock-infected PAMs from 4 pig breeds. The let-7 family miRNAs could significantly inhibit PRRSV-2 replication by directly targeting the 3’UTR of the PRRSV-2 genome and porcine IL6, which plays an important role in PRRSV replication and lung injury. NEAT1 acts as a competing endogenous lncRNA (ceRNA) to upregulate IL6 by attaching let-7 in PAMs. EMSA and ChIP results confirmed that ARID3A could bind to the promoter region of pri-let-7a/let-7f/let-7d gene cluster and inhibit the expression of the let-7 family. Moreover, the NF-κB signaling pathway inhibits the expression of the let-7 family by affecting the nuclear import of ARID3A. The pEGFP-N1-let-7 significantly reduced viral infections and pathological changes in PRRSV-infected piglets. Taken together, NEAT1/ARID3A/let-7/IL6 play significant roles in PRRSV-2 infection and may be promising therapeutic targets for PRRS.

There are significant differences in susceptibility/resistance to PRRSV among different pig breeds. Especially the local pig breeds in China had strong resistance to PRRSV. However, due to the complexity of the interaction mechanism between pigs and PRRSV, the genetic mechanism leading to PRRSV susceptibility/resistance in different pig breeds is still unclear. MiRNAs play a vital regulatory role in immune response and development of PRRS. In this study, we found that the expression of miRNA let-7 family members were significantly different in PRRSV-infected/mock-infected PAMs from Pietrain, Qingping, Meishan, and Landrace pigs. Our findings illustrated that NEAT1/ARID3A/let-7/IL6 had a significant role in PRRSV-2 infection. What’s more, let-7 family could significantly reduce PRRSV infection and pathological changes in vitro and in vivo. This discovery provided a new idea for breeding PRRSV resistant pigs by revealing the molecular mechanism of PRRSV susceptibility in different pig breeds. Altogether, let-7 family have significant roles in PRRSV infection and may be promising therapeutic targets for PRRS.

Ameliorating effects of electroacupuncture on the low-grade intestinal inflammation in rat model of diarrhea-predominant irritable bowel syndrome

BACKGROUND AND AIM

We aim to investigate the effects and mechanisms of electroacupuncture (EA) at ST25 and ST37 on the intestinal low-grade inflammation (LGI) in rat model of Diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

IBS-D model rats were established by acetic acid enema combined with restraint and tail clamping. Before EA intervention, they were divided into three groups: blank 1 group, blank 2 group, and IBS-D model group. Diarrhea symptoms and visceral pain sensitivity were evaluated. After constructed the model successfully, the remaining IBS-D model group rats were randomly divided into model group and EA group. Local intestinal inflammation (HE staining), changes of intestinal mucosa (occludin protein and microvascular diameter) were evaluated. Differences between two groups were compared using t-test or Mann-Whitney U-test. Differences among more than two groups were compared using one-way ANOVA or Kruskal-Wallis test.

RESULTS

After modeling, the results of HE staining in intestinal tract of IBS-D model rats showed LGI. Compared with the model group, 4 h fecal moisture content (diarrhea index) and the AWR score were decreased in the EA group. The results of HE in EA group showed that the infiltration of intestinal inflammatory cells were alleviated. Additionally, EA significantly upregulated the expression of occludin protein and partially dilated the intestinal microvascular diameter. Pearson correlation analysis showed that the symptoms of IBS-D rats were correlated with the changes of intestinal mucosa.

CONCLUSION

EA may treat intestinal LGI in IBS-D rats by upregulating the expression of occludin protein and dilating the intestinal microvascular diameter.

Comparative Transcriptome Analysis of Spleen Reveals Potential Regulation of Genes and Immune Pathways Following Administration of Aeromonas salmonicida subsp. masoucida Vaccine in Atlantic Salmon (Salmo salar)

Aeromonas salmonicida is a global fish pathogen. Aeromonas salmonicida subsp. masoucida (ASM) is classified as atypical A. salmonicida and caused huge losses to salmonid industry in China. Hence, it is of great significance to develop ASM vaccine and explore its protection mechanism in salmonids. In this regard, we conducted RNA-seq analysis with spleen tissue of Atlantic salmon after ASM vaccination to reveal genes, their expression patterns, and pathways involved in immune protections. In our results, a total of 441.63 million clean reads were obtained, and 389.37 million reads were mapped onto the Atlantic salmon reference genome. In addition, 1125, 2126, 1098, 820, and 1351 genes were significantly up-regulated, and 747, 2626, 818, 254, and 908 genes were significantly down-regulated post-ASM vaccination at 12 h, 24 h, 1 month, 2 months, and 3 months, respectively. Subsequent pathway analysis revealed that many differentially expressed genes (DEGs) following ASM vaccination were involved in cytokine-cytokine receptor interaction (TNFRSF11b, IL-17RA, CCR9, and CXCL11), HTLV-I infection (MR1 and HTLV-1), MAPK signaling pathway (MAPK, IL8, and TNF-α-1), PI3K-Akt signaling pathway (PIK3R3, THBS4, and COL2A1), and TNF signaling pathway (PTGS2, TNFRSF21-l, and CXCL10). Finally, the results of qRT-PCR showed a significant correlation with RNA-seq results, suggesting the reliability of RNA-seq for gene expression analysis. This study provided insights into regulation of gene expression and their involved pathways in Atlantic salmon spleen in responses to vaccine, and set the foundation for further study on the vaccine protective mechanism in Atlantic salmon as well as other teleost species.

Shenqi compound ameliorates type-2 diabetes mellitus by modulating the gut microbiota and metabolites

The gut microbiota (GM) and metabolites are important factors in mediating the development of type-2 diabetes mellitus (T2DM). An imbalance in the gut microbiota and metabolites can disrupt the function of the intestinal barrier, cause changes in the permeability of the intestinal mucosa and promote the immune inflammatory response, thereby aggravating the fluctuation of blood glucose level and promoting the occurrence and development of the chronic complications of DM. Manipulating the GM and metabolites is a promising therapeutic intervention and is being studied extensively. Shenqi compound (SQC) is a traditional Chinese medicine formulation, which has been widely used to improve T2DM. Studies have demonstrated that SQC can reduce glycemic variability, alleviate the inflammatory response, etc. However, its underlying mechanism remains unknown. Therefore, in this experiment, We administered SQC to Goto-Kakizaki (GK) rats and evaluated its effect on blood glucose homeostasis and the intestinal mucosal barrier. We identified the profiles of the GM and metabolites with the aid of 16S rDNA gene sequencing and non-target metabolomics analysis. It showed that SQC intervention could reduce glycemic variability, regulate serum levels of glucagon and insulin, and improve injury to the intestinal mucosal barrier of GK rats. In the gut, the ratio of bacteria of the phyla Bacteroidetes/Firmicutes could be improved after SQC intervention. SQC also regulated the relative abundance of Prevotellaceae, Butyricimonas, Bacteroides, Blautia, Roseburia, Lactobacillus, and Rothia. We found out that expression of 40 metabolites was significantly improved after SQC intervention. Further analyses of metabolic pathways indicated that the therapeutic effect of SQC might be related predominantly to its ability to improve gluconeogenesis/glycolysis, amino acid metabolism, lipid metabolism, citrate cycle, and butanoate metabolism. These results suggest that SQC may exert a beneficial role in T2DM by modulating the GM and metabolites in different pathways.

Dietary taurine modulates hepatic oxidative status, ER stress and inflammation in juvenile turbot (Scophthalmus maximus L.) fed high carbohydrate diets

This study was conducted to explore the beneficial role of taurine against chronic high carbohydrate diet-induced oxidative stress, endoplasmic reticulum (ER) stress and inflammation, and to understand the underlying molecular mechanisms in turbot. Two 10-week feeding trials were simultaneously conducted. For the one, six experimental diets with graded levels of taurine supplementation (0, 0.4%, 0.8%, 1.2%, 1.6% and, 2.0%, respectively) and 15% of carbohydrate were used. For the other one, three graded levels of dietary taurine supplementation (0.4%, 1.2% and 2.0%, respectively) with 21% of carbohydrate were used. The results showed that higher expression level of inflammation cytokines and ER stress related genes were detected in higher dietary carbohydrate group. In both feeding trials, 1.2% of dietary taurine supplementation improved anti-oxidative status by decreasing the content of malondialdehyde, increasing the catalase activity and total anti-oxidative capacities. In feeding trial 1, appropriate taurine supplementation lowered contents of tumour necrosis factor-a, interleukin-6, aspartate aminotransferase and alkaline phosphatase in plasma, and decreased the expressions of pro-inflammatory cytokines, such as interleukin-8 (il-8) and interferon-γ (ifn-γ). Furthermore, dietary taurine reduced ER stress by decreasing the mRNA levels of activating transcription factor 6, protein kinase R-like endoplasmic reticulum kinase and G protein-coupled receptor 78. The optimal dietary taurine content was estimated as 1.40% based on the analysis of specific growth rate. In feeding trial 2, dietary taurine supplementation attenuated liver inflammation partly referring to significantly down-regulated mRNA levels of nuclear transcription factor-κB p65, ifn-γ, interleukin1β and up-regulate the transcript of ribosomal protein S6 kinase 1. Dietary taurine supplementation in feeding trial 2 significantly increased the Nrf2-related factor 2 protein level and decreased the NFκB p65 protein level only at 21% of dietary carbohydrate level. Taurine can alleviate the oxidative damage and inflammation caused by 21% of dietary carbohydrate to a certain degree. Overall, the present study confirmed that dietary taurine supplementation improved growth performance and anti-oxidative response, and reduced liver inflammatory and ER stress processes induced by high dietary carbohydrate in turbot.

Inhibition of colitis by ring-modified analogues of 6-acetamido-2,4,5-trimethylpyridin-3-ol

6-Aminopyridin-3-ol scaffold has shown an excellent anti-inflammatory bowel disease activity. Various analogues with the scaffold were synthesized in pursuit of the diversity of side chains tethering on the C(6)-position. Structure-activity relationship among the analogues was investigated to understand the effects of the side chains and their linkers on their anti-inflammatory activities. In this study, structural modification moved beyond side chains on the C(6)-position and reached to pyridine ring itself. It expedited us to synthesize diverse ring-modified analogues of a representative pyridine-3-ol, 6-acetamido-2,4,5-trimethylpyridin-3-ol (9). In the evaluation of compounds on their inhibitory actions against TNF-α-induced adhesion of monocytic cells to colonic epithelial cells, an in vitro model mimicking colon inflammation, the effects of compounds 9, 17, and 19 were greater than tofacitinib, an orally available anti-colitis drug, and compound 17 showed the greatest activity. In addition, TNF-α-induced angiogenesis, which permits more inflammatory cell migration into inflamed tissues, was significantly blocked by compounds 17 and 19 in a concentration-dependent manner. In the comparison of in vivo therapeutic effects of compounds 9, 17, and 19 on dextran sulfate sodium (DSS)-induced colitis in mice, compound 17 was the most potent and efficacious, and compound 19 was better than compound 9 which showed a similar degree of inhibitory effect to tofacitinib. Taken together, it seems that either the trimethyl system or the hydroxyl group on the pyridinol ring is essential to the activity. This finding might become a new milestone in the development of pyridinol-based anti-inflammatory bowel disease agents.

Macrolactin A protects against LPS-induced bone loss by regulation of bone remodeling

An imbalance between bone resorption and bone formation leads to several kinds of bone diseases such as rheumatoid arthritis, osteoporosis and Paget's disease. The imbalance between bone formations relative to bone resorption is responsible in bone remodeling. Several studies have suggested that macrolactin A (MA) has potent anti-inflammatory, anti-cancer and anti-angiogenic effects in various cell types. We investigate whether macrolactin A (MA) could inhibit bone loss and enhance bone formation. We used bone marrow monocytes/macrophages (BMMs) cells to study osteoclast activity and MC3T3-E1 cells to study osteoblast activity. MA suppressed tartrate resistant acid phosphatase (TRAP) positive multinucleated cells in a concentration-dependent manner, as well as at a specific time point. MA markedly reduced bone resorption activity and F-actin ring formation. Moreover, MA markedly suppressed receptor activator of nuclear factor k-B ligand (RANKL)-induced osteoclastogenic marker genes and transcription factors in-vitro. MA repressed osteoclast differentiation via activation of the phosphoinositide kinase-3/Akt, extracellular signal-regulated kinase 1/2 (ERK 1/2), c-Jun N-terminal kinase (JNK), nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) and c-Fos signaling pathways. MA enhanced pre-osteoblast cell differentiation on mineralization activity, alkaline phosphatase (ALP) activity, and the expression of osteoblastogenic markers including osterix, RUNX-2, SMAD4, BMP-2, and ALP. Importantly, MA repressed lipopolysaccharide (LPS)-induced inflammatory bone loss in mice as shown by TRAP staining of femurs and μCT analysis. Therefore, MA could be a promising candidate for the inhibition and management of osteoporosis, arthritis, and bone lytic diseases.

Marine Microorganism-Derived Macrolactins Inhibit Inflammatory Mediator Effects in LPS-Induced Macrophage and Microglial Cells by Regulating BACH1 and HO-1/Nrf2 Signals through Inhibition of TLR4 Activation

Recently, many natural products with unique structure and promising pharmacological potential have been reported from marine-derived microorganisms. The macrolactin A (MA), 15-epi-dihydromacrolactin F (DMF) and macrolactin F (MF) were obtained from the culture broth extract of a marine sediment derived microorganism Bacillus sp. HC001. In this study, MA, DMF and MF inhibited the production and expression of proinflammatory mediators of inducible nitric oxide synthase (iNOS) and cyclooxygenase–2 (COX-2) in LPS-stimulated RAW264.7 and BV2 cells. Also, MA, DMF and MF exert anti-inflammatory effects through the expression of heme oxygenase (HO) -1, a stress-inducing enzyme that converts heme to carbon monoxide (CO), iron and biliberdine. Toll-like receptor 4 (TLR4) expressed by lipopolysaccharide (LPS) was inhibited by increased expression of HO-1 transcription factor Nrf2 and down regulation of BTB Domain And CNC Homolog 1 (BACH1), inhibited phosphorylation of Mitogen-activated protein kinase kinase kinase 7 (MAP3K7, TAK1) and nuclear factor kappaB (NF-κB). These results show that MA, DMF and MF effectively inhibited TLR4 by regulating BACH1 and HO-1/Nrf2 signals in LPS-stimulated RAW264.7 and BV2 cells, which suggests the possibility of use as an anti-inflammatory agent.

Onion bulb extract reduces colitis severity in mice via modulation of colonic inflammatory pathways and the apoptotic machinery

ETHNOPHARMACOLOGICAL RELEVANCE

The use of nutraceutical-based products has increased in recent years due to their demonstrated efficacy and their good safety profile. Onion is one of the most commonly used plants in the traditional medicine for the management of various conditions including inflammatory and gastrointestinal diseases. However, little is known regarding the molecular mechanism of the anti-inflammatory effects of onion particularly in inflammatory bowel disease (IBD).

AIM OF THE STUDY

To test the anti-inflammatory effects of onion bulb extract (OBE) in an IBD mouse model and the molecular mechanisms responsible for these effects such as modulation of the expression and/or the activity profile of various pro-inflammatory molecules.

MATERIALS AND METHODS

Colitis was induced in mice by dextran sulfate sodium (DSS) daily administration for 5 days. Animals were sacrificed, colons were removed and the severity of the inflammation was determined by the gross and histological assessments. The colonic level/activity of various cytokines and chemokines were measured using proteome profiling-based assay, western blotting, and immunofluorescence techniques.

RESULTS

DSS-induced colitis was significantly reduced by the daily OBE treatment and 5-aminosalicylic acid (5-ASA, positive control), particularly at 100-200 mg/kg doses, at both the gross and histological levels. OBE was also shown to reduce colonic expression and activity of several pro-inflammatory molecules and signaling pathways, such as mitogen activated protein kinase family, mammalian target of rapamycin, cyclooxygenase-2, and tissue inhibitors of metalloproteinases. In addition, OBE reduced the expression of interferon-γ, various C-C and C-X-C chemokines, and molecules involved in the apoptotic machinery such as cytochrome c, caspase-3 and -8, B-cell lymphoma-extra-large and -2.

CONCLUSIONS

OBE showed anti-inflammatory actions in IBD mouse model, which is attributed, in part, to the modulation of the expression and the activity of important pro-inflammatory molecules and signaling pathways involved in the inflammatory response. These data suggest that OBE may be a promising lead in the therapeutic management of IBD.

Bioactive Secondary Metabolites from Bacillus subtilis: A Comprehensive Review

Bacillus subtilis is widely underappreciated for its inherent biosynthetic potential. This report comprehensively summarizes the known bioactive secondary metabolites from B. subtilis and highlights potential applications as plant pathogen control agents, drugs, and biosurfactants. B. subtilis is well known for the production of cyclic lipopeptides exhibiting strong surfactant and antimicrobial activities, such as surfactins, iturins, and fengycins. Several polyketide-derived macrolides as well as nonribosomal peptides, dihydroisocoumarins, and linear lipopeptides with antimicrobial properties have been reported, demonstrating the biosynthetic arsenal of this bacterium. Promising efforts toward the application of B. subtilis strains and their natural products in areas of agriculture and medicine are underway. However, industrial-scale availability of these compounds is currently limited by low fermentation yields and challenging accessibility via synthesis, necessitating the development of genetically engineered strains and optimized cultivation processes. We hope that this review will attract renewed interest in this often-overlooked bacterium and its impressive biosynthetic skill set.

Synthesis and evaluation of 6-heteroarylamino-2,4,5-trimethylpyridin-3-ols as inhibitors of TNF-α-induced cell adhesion and inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disease of the gastrointestinal tract with complex pathogenesis. Here, we synthesized 6-heteroarylamino analogues to inhibit TNF-α-induced adhesion of monocytes to colon epithelial cells which are implicated in the initial inflammation process of IBD. The best analogue, 16a, showed IC50 = 0.29 μM, which is about five orders of magnitude better than that of 5-aminosalicylic acid (5-ASA), a positive control. Oral administration of 6f and 16a dramatically ameliorated 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colon inflammation in rat. The ameliorating effects were accompanied by a high level of recovery in colon and body weights and in the myeloperoxidase (MPO) level. Consistently, the compounds suppressed the expression of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein 1 (MCP-1). Moreover, they significantly suppressed the expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 while increasing the level of IL-10, an anti-inflammatory cytokine.

Oxymatrine protects against DSS-induced colitis via inhibiting the PI3K/AKT signaling pathway

Oxymatrine (OMT), an alkaloid derived from the root of the Sophora flavescens, has been reported to possess a significant effect on relieving UC owing to its anti-inflammatory property. But the other therapeutic mechanism of OMT remains unclear. Recent studies have found, PI3K/AKT signaling pathway is involved in the pathogenesis of UC by pro-inflammatory effects and activating T cells. Moreover, PI3K/AKT pathway is one of the most important pathways for regulating cell apoptosis. Thus, we aim to explore whether OMT protects against UC by targeting PI3K/AKT pathway. We established the UC mice models, using LY294002 (a specific inhibitor of PI3K/AKT) as a positive control, to observe the effect of low, medium and high dose of OMT on UC and its influence on PI3K/AKT signaling pathway. Our data indicated that OMT can significantly ameliorate UC through anti-inflammatory, pro-apoptotic, down-regulating the differentiation of Th1 and Th17 cells via PI3K/AKT pathway. This study reveals that PI3K/AKT signaling pathway is a potential mechanism of OMT-induced UC remission and suggests that OMT is a promising therapeutic agent for the treatment of UC.

The improved growth performance and enhanced immune function by DL-methionyl-DL-methionine are associated with NF-κB and TOR signalling in intestine of juvenile grass carp (Ctenopharyngodon idella)

The present study investigated the effects of dietary DL-methionyl-DL-methionine (Met-Met) on growth performance, intestinal immune function and the underlying signalling molecules in juvenile grass carp (Ctenopharyngodon idella). Fish were fed one DL-methionine (DL-Met) group (2.50 g/kg diet) and six graded levels of Met-Met groups (0, 0.79, 1.44, 1.84, 2.22 and 2.85 g/kg diet) for 10 weeks, and then challenged with Aeromonas hydrophila for 14 days. Results indicated that the optimal Met-Met supplementation: (1) increased fish growth performance, intestinal lysozyme (LZ) and acid phosphatase (ACP) activities, complement (C3 and C4) and immunoglobulin M (IgM) contents, up-regulated hepcidin, liver expressed antimicrobial peptide 2A (LEAP-2A), LEAP-2B, β-defensin-1 and Mucin2 mRNA levels; (2) down-regulated tumour necrosis factor α (TNF-α), interferon γ2 (IFN-γ2), interleukin 1β (IL-1β), IL-8 [only in the distal intestine (DI)], IL-12p35, IL-12p40 and IL-15 (not IL-17D) mRNA levels partially related to the down-regulation of IκB kinase β (IKKβ) and IKKγ (rather than IKKα), nuclear factor kappa B (NF-κB) p65 and c-Rel (rather than NF-κB p52) mRNA levels and the up-regulation of inhibitor of κBα (IκBα) mRNA levels; (3) up-regulated IL-4/13A, IL-4/13B, IL-6, IL-10, IL-11 and transforming growth factor (TGF)-β1 (not TGF-β2) mRNA levels partially associated with the target of rapamycin (TOR) signalling pathway [TOR/ribosomal protein S6 kinases 1 (S6K1), eIF4E-binding proteins (4E-BP)] in three intestinal segments of juvenile grass carp. These results suggest that Met-Met supplementation improves growth and intestinal immune function in fish. Furthermore, according to a positive effect, the optimal Met-Met supplementation was superior to the optimal DL-Met supplementation at improving the growth performance and enhancing the intestinal immune function in fish. Finally, based on percent weight gain (PWG), protection against enteritis morbidity and immune index (LZ activity), the optimal Met-Met supplementation for juvenile grass carp was estimated as 1.61, 1.64 and 1.68 g/kg diet, respectively, as the basal diet contains 8.03 g/kg total sulfur amino acids (TSAA) (4.26 g methionine/kg and 3.77 g cysteine/kg).

Combination therapy of 7-O-succinyl macrolactin A tromethamine salt and temozolomide against experimental glioblastoma

7-O-succinyl macrolactin A has shown anti-inflammatory, anti-angiogenesis, and anti-metastatic effects. It also exhibits strong suppression of tumor growth. In our previous study, we assessed the anti-neoplastic effects of 7-O-succinyl macrolactin A tromethamine salt (SMA salt) on a glioma cell line. Moreover, according to our data, SMA salt might be contributed to the inhibitory effects on migration and invasion, as well as a cytotoxic effect on the glioblastoma cell lines. In the present study, we investigated the anti-tumor effects of combination therapy with SMA salt and temozolomide (TMZ) in glioblastoma cell lines. The combination therapy affected cell viability significantly, decreasing in glioblastoma cell lines. In cell migration assays, combination therapy showed more inhibitory effects than TMZ in these cell lines. The tumor volume was significantly decreased in the combination group compared with both TMZ and control groups by using the orthotopic mouse model. The effects of combination therapy with SMA salt and TMZ attributed to the inhibition of migration, invasion activities and anti-tumor effects. SMA salt could be one of the promising candidates for combination therapy in clinical settings.

Calculation of a First-In-Man Dose of 7-O-Succinyl Macrolactin A Based on Allometric Scaling of Data from Mice, Rats, and Dogs

7-O-Succinyl macrolactin A (SMA) exerts several pharmacological effects including anti-bacterial, anti-inflammation, and anti-cancer activities. Recently, SMA has been extensively evaluated as an anti-cancer drug. Thus, the objectives of the present study were to characterise the pharmacokinetics of SMA via both non-compartmental and compartmental analysis in mice, rats, and dogs, and to derive an appropriate first-in-man dose based on allometric scaling of the animal data. The time courses of plasma SMA concentrations after intravenous administration to rats and dogs were analysed retrospectively, as were data collected after intraperitoneal SMA injection in mice. Pharmacokinetic parameters were estimated via both noncompartmental and compartmental analysis, and were correlated with body weight and/or the potential maximum life-span. The clearance and distribution volume of SMA in humans were predicted, and a first-in-man dose proposed. A two-compartment model best described the time courses of SMA plasma concentrations after a saturation elimination process was applied to fit the dataset obtained from rats. Incorporation of the maximum potential life-span during allometric scaling was required to improve the estimation of human clearance. The SMA clearance and the distribution volume in the steady state, in a 70-kg adult male, were estimated to be 30.6 L/h and 19.5 L, respectively. To meet the area under the curve (AUC) required for anti-tumour activity, a dose of 100 mg (∼1.5 mg/kg) was finally proposed as the first dose for a 70-kg human. Although toxicological profiles derived from non-clinical studies must be considered before any final decision is made, our work will facilitate clinical studies on SMA.

Sulphur dioxide suppresses inflammatory response by sulphenylating NF-κB p65 at Cys38 in a rat model of acute lung injury

The present study was designed to investigate whether endogenous sulphur dioxide (SO2) controlled pulmonary inflammation in a rat model of oleic acid (OA)-induced acute lung injury (ALI). In this model, adenovirus expressing aspartate aminotransferase (AAT) 1 was delivered to the lungs, and the levels of SO2 and proinflammatory cytokines in rat lung tissues were measured. In the human alveolar epithelial cell line A549, the nuclear translocation and DNA binding activities of wild-type (wt) and C38S (cysteine-to-serine mutation at p65 Cys38) NF-κB p65 were detected. GFP-tagged C38S p65 was purified from HEK 293 cells and the sulphenylation of NF-κB p65 was studied. OA caused a reduction in SO2/AAT pathway activity but increased pulmonary inflammation and ALI. However, either the presence of SO2 donor, a combination of Na2SO3 and NaHSO3, or AAT1 overexpression in vivo successfully blocked OA-induced pulmonary NF-κB p65 phosphorylation and consequent inflammation and ALI. Either treatment with an SO2 donor or overexpression of AAT1 down-regulated OA-induced p65 activity, but AAT1 knockdown in alveolar epithelial cells mimicked OA-induced p65 phosphorylation and inflammation in vitro. Mechanistically, OA promoted NF-κB nuclear translocation, DNA binding activity, recruitment to the intercellular cell adhesion molecule (ICAM)-1 promoter, and consequent inflammation in epithelial cells; these activities were reduced in the presence of an SO2 donor. Furthermore, SO2 induced sulphenylation of p65, which was blocked by the C38S mutation on p65 in epithelial cells. Hence, down-regulation of SO2/AAT is involved in pulmonary inflammation during ALI. Furthermore, SO2 suppressed inflammation by sulphenylating NF-κB p65 at Cys38.

Irinotecan-loaded double-reversible thermogel with improved antitumor efficacy without initial burst effect and toxicity for intramuscular administration

Intramuscularly administered, anti-tumour drugs induce severe side effects due to their direct contact with body tissues and initial burst effect. In this study, to solve this problem, a novel double-reversible thermogel system (DRTG) for the intramuscular administration of irinotecan was developed. This irinotecan-loaded DRTG was prepared by dispersing the irinotecan-loaded thermoreversible solid lipid nanoparticles (SLNs) in the thermoreversible hydrogel. In DRTG, the former was solid at 25°C but converted to liquid at 36.5°C; in contrast, the latter existed in a liquid form but transformed to gel state in the body. The DRTG was easily administered intramuscularly. Its particle size and drug content were not noticeably changeable, resulting that it was stable at 40°C for at least 6months. Compared to the irinotecan-loaded solution and conventional hydrogel, the DRTG significantly delayed drug release, leading to a reduced burst effect. Moreover, it showed decreased C_max and maintained the sustained plasma concentrations at a relatively low level for the long period of 60h in rats, resulting in ameliorated side effects of the anti-tumour drug. Furthermore, it gave significantly improved anti-tumour efficacy in tumour-bearing mice compared to the hydrogel but, unlike the conventional hydrogel, induced no body weight loss and local damage to the muscle. Thus, this DRTG with improved antitumor efficacy without initial burst effect and toxicity could provide a potential pharmaceutical system for the intramuscular administration of irinotecan.

STATEMENT OF SIGNIFICANCE

Intramuscularly administered, anti-tumour drugs induce severe side effects due to their direct contact with body tissues and initial burst effect. To solve this problem, we developed a novel double-reversible thermogel system (DRTG) for the intramuscular administration of irinotecan. Unlike the conventional hydrogel, the DRTG is a dispersion of the irinotecan-loaded thermoreversible solid lipid nanoparticles in the thermoreversible hydrogel. In DRTG, the former was solid at 25°C but converted to liquid at 36.5°C; in contrast, the latter existed in a liquid form but transformed to gel state in the body. This DRTG gave significantly improved anti-tumour efficacy in tumour-bearing mice compared to the hydrogel but, unlike the conventional hydrogel, induced no body weight loss and local damage to the muscle.

Rotundarpene inhibits TNF-α-induced activation of the Akt, mTOR, and NF-κB pathways, and the JNK and p38 associated with production of reactive oxygen species

Ilex Rotunda Thunb has been shown to have anti-inflammatory and antioxidant effects. In human keratinocytes, we investigated the effect of rotundarpene (4-caffeoyl-3-methyl-but-2-ene-1,4-diol) on the TNF-α-stimulated production of inflammatory mediators in relation to the Akt, mTOR, and NF-κB pathways, and the JNK and p38-MAPK. Rotundarpene, Akt inhibitor, Bay 11-7085, rapamycin, and N-acetylcysteine inhibited the TNF-α-stimulated production of cytokines and chemokines, increase in the levels of p-Akt and mTOR, activation of NF-κB, and production of reactive oxygen species in keratinocytes. TNF-α treatment induced phosphorylation of the JNK and p38-MAPK. Inhibitors of the c-JNK (SP600125) and p38-MAPK (SB203580) reduced the TNF-α-induced production of inflammatory mediators, binding of NF-κB to DNA, and activation of the JNK and p38-MAPK in keratinocytes. The results show that rotundarpene may reduce the TNF-α-stimulated inflammatory mediator production by suppressing the reactive oxygen species-dependent activation of the Akt, mTOR, and NF-κB pathways, and activation of the JNK and p38-MAPK in human keratinocytes. Additionally, rotundarpene appears to attenuate the Akt, mTOR, and NF-κB pathways and the JNK and p38-MAPK-mediated inflammatory skin diseases.

Irinotecan-encapsulated double-reverse thermosensitive nanocarrier system for rectal administration

Intravenously administered for the treatment of rectum cancer, irinotecan produces severe side effects due to very high plasma concentrations. A novel irinotecan-encapsulated double reverse thermosensitive nanocarrier system (DRTN) for rectal administration was developed as an alternative. The DRTN was fabricated by dispersing the thermosensitive irinotecan-encapsulated solid lipid nanoparticles (SLN) in the thermosensitive poloxamer solution. Its gel properties, pharmacokinetics, morphology, anticancer activity and immunohistopathology were assessed after its rectal administration to rats and tumor-bearing mice. In the DRTN, the solid form of the SLN and the liquid form of the poloxamer solution persisted at 25 °C; the former melted to liquid, and the latter altered to gel at 36.5 °C. The DRTN was easily administered to the anus, gelling rapidly and strongly after rectal administration. Compared to the conventional hydrogel and intravenously administered solution, it retarded dissolution and initial plasma concentration. The DRTN gave sustained release and nearly constant plasma concentrations of irinotecan at 1–3 h in rats, resulting in improved anticancer activity. It induced no damage to the rat rectum and no body weight loss in tumor-bearing mice. Thus, this irinotecan-encapsulated DRTN associated with a reduced burst effect, lack of toxicity and excellent antitumor efficacy would be strongly recommended as a rectal pharmaceutical product alternative to commercial intravenous injection in the treatment of rectum and colon cancer.

Antitumor activity of 7-O-succinyl macrolactin A tromethamine salt in the mouse glioma model

Chemoradiotherapy with temozolomide is the current standard treatment option for patients with glioblastoma. However, the majority of patients with glioblastoma survive for <2 years. Therefore, it is necessary to develop more effective therapeutic strategies for the treatment of glioblastoma. 7-O-succinyl macrolactin A tromethamine salt (SMA salt), a macrolactin compound, is known to possess an antiangiogenic activity. The present study investigated the antitumor effects of SMA salt in the treatment of glioblastoma by evaluating in vitro and in vivo antitumor effects of SMA salt in an experimental glioblastoma model. The antitumor effects of the drug on human glioblastoma U87MG, U251MG and LN229 cell lines were assessed using in vitro cell viability, migration and invasion assays. Nude mice with established U87MG glioblastoma were assigned to either the control or SMA salt treatment group. The volume of tumors and the duration of survival were also measured. SMA salt affected cell viability and caused a concentration-dependent inhibition effect on the migration and invasion of glioblastoma cell lines. Animals in the SMA salt treatment group demonstrated a significant reduction in tumor volume and an increase in survival (P<0.05). Treatment with SMA salt presented more cytotoxic effects as well as anti-migration and anti-invasion activity compared with the control group in vitro and in vivo. These results suggest that SMA salt has significant antitumor effects on glioblastoma.

Protective Effect of Protocatechuic Acid on TNBS-Induced Colitis in Mice Is Associated with Modulation of the SphK/S1P Signaling Pathway

(1) Background: The present study aimed to investigate whether beneficial effects of protocatechuic acid (PCA) are associated with inhibition of the SphK/S1P axis and related signaling pathways in a 2,4,6-trinitrobenzenesulfonic acid (TNBS) model of inflammatory bowel disease; (2) Methods: Colitis was induced in male Balb/c mice by intracolonic administration of 2 mg of TNBS. PCA (30 or 60 mg/kg body wt) was given intraperitoneally daily for five days; (3) Results: Administration of PCA prevented the macroscopic and microscopic damage to the colonic mucosa, the decrease in body weight gain and the increase in myeloperoxidase activity induced by TNBS. PCA-treated mice exhibited a lower oxidized/reduced glutathione ratio, increased expression of antioxidant enzymes and Nrf2 and reduced expression of proinflammatory cytokines. Following TNBS treatment mRNA levels, protein concentration and immunohistochemical labelling for SphK1 increased significantly. S1P production and expression of S1P receptor 1 and S1P phosphatase 2 were significantly elevated. However, there was a decreased expression of S1P lyase. Furthermore, TNBS-treated mice exhibited increased phosphorylation of AKT and ERK, and a higher expression of pSTAT3 and the NF-κB p65 subunit. PCA administration significantly prevented those changes; (4) Conclusions: Data obtained suggest a contribution of the SphK/S1P system and related signaling pathways to the anti-inflammatory effect of PCA.

Anti-Inflammatory Properties of the Enaminone E121 in the Dextran Sulfate Sodium (DSS) Colitis Model

BACKGROUND

Enaminones are synthetic compounds with an established role in the prevention of various forms of seizures. Recent evidence suggests potent anti-tussive, bronchodilation and anti-inflammatory properties. Pre-treatment with particularly E121 compound resulted in a decrease in leukocyte recruitment in the ovalbumin induced-model of asthma, immune cell proliferation and cytokine release in vitro. We hypothesize that E121 might serve as a therapeutic potential in intestinal inflammation through modulating immune cell functions.

METHODS

Colitis was induced by daily dextran sulfate sodium (DSS) administration for 5 days, and its severity was determined by gross and histological assessments. The plasma level of various cytokines was measured using flow cytometry-based assay. The colonic expression/ phosphorylation level of various molecules was determined by immunofluorescence and western blotting. The effects of E121 treatment on in vitro neutrophil chemotaxis (under-agarose assay), superoxide release (luminol oxidation assay) and apoptosis (annexin V/7AAD) were also determined.

RESULTS

DSS-induced colitis in mice was significantly reduced by daily E121 treatment (30-100 mg/kg) at gross and histological levels. This effect was due to modulated plasma levels of interleukin (IL-2) and colonic expression levels of various signaling molecules and proteins involved in apoptosis. In vitro neutrophil survival, chemotaxis, and superoxide release were also reduced by E121 treatment.

CONCLUSION

Our results indicate important anti-inflammatory actions of E121 in the pathogenesis of IBD.

Antibacterial Compounds-Macrolactin Alters the Soil Bacterial Community and Abundance of the Gene Encoding PKS

Macrolactin produced by many soil microbes has been shown to be an efficient antibacterial agent against many bacterial pathogens. However, studies examining the effect of macrolactin on both the soil bacterial community and the intrinsic bacterial species that harbor genes responsible for the production of this antibiotic have not been conducted so far. In this study, a mixture of macrolactin was isolated from the liquid culture of Bacillus amyloliquefaciens NJN-6, and applied to the soil once a week for four weeks. 16S rRNA Illumina MiSeq sequencing showed that continuous application of macrolactin reduced the α-diversity of the soil bacterial community and thereby changed the relative abundance of microbes at both the phylum and genus level. The relative abundance of Proteobacteria and Firmicutes was significantly increased along with a significant decrease in the relative abundance of Acidobacteria. However, the application of macrolactins had an insignificant effect on the total numbers of bacteria. Further, the native gene responsible for the production of macrolactin, the gene encoding polyketide synthase was reduced in copy number after the application of macrolactin. The results of this study suggested that a bactericide from a microbial source could decrease the diversity of the soil bacterial community and change the bacterial community structure. Moreover, the populations of the intrinsic bacterial species which harbor genes responsible for macrolactin production were inhibited when the external source antibiotic was applied.

Inflammatory bowel disease: exploring gut pathophysiology for novel therapeutic targets

Ulcerative colitis and Crohn's disease are the 2 major phenotypes of inflammatory bowel disease (IBD), which are influenced by a complex interplay of immunological and genetic elements, though the precise etiology still remains unknown. With IBD developing into a globally prevailing disease, there is a need to explore new targets and a thorough understanding of the pathophysiological differences between the healthy and diseased gut could unearth new therapeutic opportunities. In this review, we provide an overview of the major aspects of IBD pathogenesis and thereafter present a comprehensive analysis of the gut pathophysiology leading to a discussion on some of the most promising targets and biologic therapies currently being explored. These include various gut proteins (CXCL-10, GATA-3, NKG2D, CD98, microRNAs), immune cells recruited to the gut (mast cells, eosinophils, toll-like receptors 2, 4), dysregulated proinflammatory cytokines (interleukin-6, -13, -18, -21), and commensal microbiota (probiotics and fecal microbiota transplantation). We also evaluate some of the emerging nonconventional therapies being explored in IBD treatment focusing on the latest developments in stem cell research, oral targeting of the gut-associated lymphoid tissue, novel anti-inflammatory signaling pathway targeting, adenosine deaminase inhibition, and the beneficial effects of antioxidant and nutraceutical therapies. In addition, we highlight the growth of biologics and their targets in IBD by providing information on the preclinical and clinical development of over 60 biopharmaceuticals representing the state of the art in ulcerative colitis and Crohn's disease drug development.

In vitro and in vivo inhibitory activity of 6-amino-2,4,5-trimethylpyridin-3-ols against inflammatory bowel disease

Although the pathogenesis of inflammatory bowel disease (IBD) is complex, attachment and infiltration of leukocytes to gut epithelium induced by pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) represents the initial step of inflammation in IBD. Previously, we have reported that some 6-amino-2,4,5-trimethylpyridin-3-ols have significant levels of antiangiogenic activity via PI3K inhibition. Based on the reports that angiogenesis is involved in the aggravation of IBD and that PI3K is a potential target for IBD therapy, we investigated whether the scaffold has inhibitory activity against in vitro and in vivo models of colitis. Many analogues showed >80% inhibition against TNF-α-induced monocyte adhesion to colon epithelial cells at 1μM. Compound 8m showed IC50=0.19μM, which is about five orders of magnitude better than that of 5-aminosalicylic acid (5-ASA, IC50=18.1mM), a positive control. In a rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis, orally administered 8m dramatically ameliorated TNBS-induced colon inflammation. It was demonstrated by a high level of suppression in myeloperoxidase (MPO), a surrogate marker of colitis, as well as almost perfect recovery of colon and body weights in a dose-dependent manner. Compared to sulfasalazine, a prodrug of 5-ASA, compound 8m showed >300-fold better efficacy in those parameters. Taken together, 6-amino-2,4,5-trimethylpyridin-3-ols can provide a novel platform for anti-IBD drug discovery.

Urinary Bladder-Relaxant Effect of Kurarinone Depending on Potentiation of Large-Conductance Ca2+-Activated K+ Channels

The large-conductance calcium-activated potassium channel (BKCa channel) plays critical roles in smooth muscle relaxation. In urinary bladder smooth muscle, BKCa channel activity underlies the maintenance of the resting membrane potential and repolarization of the spontaneous action potential triggering the phasic contraction. To identify novel BKCa channel activators, we screened a library of natural compounds using a cell-based fluorescence assay and a hyperactive mutant BKCa channel (Lee et al., 2013). From 794 natural compounds, kurarinone, a flavanone from Sophora flavescens, strongly potentiated BKCa channels. When treated from the extracellular side, this compound progressively shifted the conductance-voltage relationship of BKCa channels to more negative voltages and increased the maximum conductance in a dose-dependent manner. Whereas kurarinone strongly potentiated the homomeric BKCa channel composed of only the α subunit, its effects were much smaller on heteromeric channels coassembled with auxiliary β subunits. Although the activation kinetics was not altered significantly, the deactivation of BKCa channels was dramatically slowed by kurarinone treatment. At the single-channel level, kurarinone increased the open probability of the BKCa channel without affecting its single-channel conductance. Kurarinone potently relaxed acetylcholine-induced contraction of rat bladder smooth muscle and thus decreased the micturition frequency of rats with overactive bladder symptoms. These results indicate that kurarinone can directly potentiate BKCa channels and demonstrate the therapeutic potentials of kurarinone and its derivatives for developing antioveractive bladder medications and supplements.

Flavonoid myricetin inhibits TNF-α-stimulated production of inflammatory mediators by suppressing the Akt, mTOR and NF-κB pathways in human keratinocytes

Flavonoid myricetin has been shown to exhibit anti-inflammatory and anti-oxidant effects. Nevertheless, the effect of myricetin on the TNF-α-stimulated production of inflammatory mediators in keratinocytes has not been studied. Using human keratinocytes, we examined the effect of myricetin on the TNF-α-stimulated production of inflammatory mediators in relation to the Akt, mTOR and NF-κB pathways, which regulate the transcription genes involved in immune and inflammatory responses. TNF-α stimulated production of the inflammatory mediators and reactive oxygen species in keratinocytes, and activation of the Akt, mTOR and NF-κB pathways in HaCaT cells and primary keratinocytes. Myricetin, Akt inhibitor, Bay 11-7085 (an inhibitor of NF-κB activation), rapamycin (mTOR inhibitor) and N-acetylcysteine attenuated TNF-α-induced activation of Akt, mTOR and NF-κB. Myricetin and N-acetylcysteine attenuated the TNF-α-stimulated production of cytokines and chemokines, and production of reactive oxygen species in keratinocytes. The results show that myricetin may reduce TNF-α-stimulated inflammatory mediator production in keratinocytes by suppressing the activation of the Akt, mTOR and NF-κB pathways. The effect of myricetin appears to be associated with inhibition of the production of reactive oxygen species. Further, myricetin appears to attenuate the proinflammatory mediator-induced inflammatory skin diseases.

The Anti-Tumor Activity of Succinyl Macrolactin A Is Mediated through the β-Catenin Destruction Complex via the Suppression of Tankyrase and PI3K/Akt

Accumulated gene mutations in cancer suggest that multi-targeted suppression of affected signaling networks is a promising strategy for cancer treatment. In the present study, we report that 7-O-succinyl macrolactin A (SMA) suppresses tumor growth by stabilizing the β-catenin destruction complex, which was achieved through inhibition of regulatory components associated with the complex. SMA significantly reduced the activities of PI3K/Akt, which corresponded with a decrease in GSK3β phosphorylation, an increase in β-catenin phosphorylation, and a reduction in nuclear β-catenin content in HT29 human colon cancer cells. At the same time, the activity of tankyrase, which inhibits the β-catenin destruction complex by destabilizing the axin level, was suppressed by SMA. Despite the low potency of SMA against tankyrase activity (IC₅₀ of 50.1 μM and 15.5 μM for tankyrase 1 and 2, respectively) compared to XAV939 (IC₅₀ of 11 nM for tankyrase 1), a selective and potent tankyrase inhibitor, SMA had strong inhibitory effects on β-catenin-dependent TCF/LEF1 transcriptional activity (IC₅₀ of 39.8 nM), which were similar to that of XAV939 (IC₅₀ of 28.1 nM). In addition to suppressing the colony forming ability of colon cancer cells in vitro, SMA significantly inhibited tumor growth in CT26 syngenic and HT29 xenograft mouse tumor models. Furthermore, treating mice with SMA in combination with 5-FU in a colon cancer xenograft model or with cisplatin in an A549 lung cancer xenograft model resulted in greater anti-tumor activity than did treatment with the drugs alone. In the xenograft tumor tissues, SMA dose-dependently inhibited nuclear β-catenin along with reductions in GSK3β phosphorylation and increases in axin levels. These results suggest that SMA is a possible candidate as an effective anti-cancer agent alone or in combination with cytotoxic chemotherapeutic drugs, such as 5-FU and cisplatin, and that the mode of action for SMA involves stabilization of the β-catenin destruction complex through inhibition of tankyrase and the PI3K/Akt signaling pathway.

Anti-angiogenic activity of macrolactin A and its succinyl derivative is mediated through inhibition of class I PI3K activity and its signaling

In the current study, macrolactin compounds, macrolactin A (MA) and 7-O-succinyl macrolactin A (SMA), were investigated for their anti-angiogenic activities and action mechanism. MA and SMA inhibited in vitro and in vivo angiogenesis induced by three different classes of pro-angiogenic factors, VEGF, IL-8, and TNF-α. SMA exhibited stronger anti-angiogenic activity than MA, and such anti-angiogenic activity of SMA was consistently observed in MDA-MB-231 human breast cancer cell-inoculated CAM assay showing dose-dependent suppression of tumor growth and tumor-induced angiogenesis. In an in vitro PI3K competitive activity assay, SMA induced concentration-dependent inhibition of class I PI3K isoforms, p110α, p110β, p110δ, and p110γ. In addition, non-receptor tyrosine kinase c-Src, which is involved in the activation of PI3K heterodimer, was suppressed by MA and SMA. Correspondingly, MA and SMA significantly inhibited the stimulus-induced phosphorylation of Akt, mTOR, p70S6K, and ribosomal S6 in human umbilical vein endothelial cells (HUVECs). At the same time, the stimulus-induced production of reactive oxygen species (ROS) and activation of NF-κB were significantly suppressed by MA and SMA. Moreover, the macrolactins suppressed NF-κB-regulated HSP90 protein expression, which stabilizes phosphorylated Akt and NADPH oxidase. Suppression of NF-κB in macrolactin-treated HUVECs with concurrent inhibition of rS6 indicates that MAs effectively block angiogenesis through down-regulation of genes related to angiogenesis at both transcriptional and translational levels. Taken together, the results demonstrate that anti-angiogenic effect of MA and SMA is mediated through inhibition of PI3K/Akt and NADPH oxidase-derived ROS/NF-κB signaling pathways. These results further indicate that MA and SMA may be applicable for treatment of various diseases associated with angiogenesis.

PI3K/AKT/PTEN pathway as a target for Crohn's disease therapy (Review)

The pathogenesis of inflammatory bowel disease (IBD), including Crohn's disease, is a subject of increasing interest. Loss-of-function mutations in nucleotide-binding oligomerization domain-containing protein 2 (NOD2) are strong genetic factors linked to Crohn's disease, which eventually leads to an excessive mucosal inflammatory response directed against components of normal gut microbiota. Reactive oxygen species (ROS) play an important role in inflammation processes, as well as in transduction of signals from receptors for several cytokines, such as tumor necrosis factor α (TNFα). ROS activate nuclear factor-κB (NF-κB) via IκB kinase (IKK) through the PI3K/AKT/PTEN pathway. Therefore, this pathway is recognized to play a key role in Crohn's disease. Loss of function has been demonstrated to occur as an early event in a wide variety of diseases. Given this prevalent involvement in a number of diseases, the molecular development that modulates this pathway has been the subject of several studies. In addition, it has been the focus of extensive research and drug discovery activities. A better understanding of the molecular assemblies may reveal novel targets for the therapeutic development against Crohn's disease.

Overnutrition, mTOR signaling, and cardiovascular diseases

The prevalence of obesity and associated medical disorders has increased dramatically in the United States and throughout much of the world in the past decade. Obesity, induced by excess intake of carbohydrates and fats, is a major cause of Type 2 diabetes, hypertension, and the cardiorenal metabolic syndrome. There is emerging evidence that excessive nutrient intake promotes signaling through the mammalian target of rapamycin (mTOR), which, in turn, may lead to alterations of cellular metabolic signaling leading to insulin resistance and obesity-related diseases, such as diabetes, cardiovascular and kidney disease, as well as cancer. While the pivotal role of mTOR signaling in regulating metabolic stress, autophagy, and adaptive immune responses has received increasing attention, there remain many gaps in our knowledge regarding this important nutrient sensor. For example, the precise cellular signaling mechanisms linking excessive nutrient intake and enhanced mTOR signaling with increased cardiovascular and kidney disease, as well as cancer, are not well understood. In this review, we focus on the effects that the interaction between excess intake of nutrients and enhanced mTOR signaling have on the promotion of obesity-associated diseases and potential therapeutic strategies involving targeting mTOR signaling.

Lactoferrin deficiency promotes colitis-associated colorectal dysplasia in mice

Nonresolving inflammatory processes affect all stages of carcinogenesis. Lactoferrin, a member of the transferrin family, is involved in the innate immune response and anti-inflammatory, anti-microbial, and anti-tumor activities. We previously found that lactoferrin is significantly down-regulated in specimens of nasopharyngeal carcinoma (NPC) and negatively associated with tumor progression, metastasis, and prognosis of patients with NPC. Additionally, lactoferrin expression levels are decreased in colorectal cancer as compared with normal tissue. Lactoferrin levels are also increased in the various phases of inflammation and dysplasia in an azoxymethane-dextran sulfate sodium (AOM-DSS) model of colitis-associated colon cancer (CAC). We thus hypothesized that the anti-inflammatory function of lactoferrin may contribute to its anti-tumor activity. Here we generated a new Lactoferrin knockout mouse model in which the mice are fertile, develop normally, and display no gross morphological abnormalities. We then challenged these mice with chemically induced intestinal inflammation to investigate the role of lactoferrin in inflammation and cancer development. Lactoferrin knockout mice demonstrated a great susceptibility to inflammation-induced colorectal dysplasia, and this characteristic may be related to inhibition of NF-κB and AKT/mTOR signaling as well as regulation of cell apoptosis and proliferation. Our results suggest that the protective roles of lactoferrin in colorectal mucosal immunity and inflammation-related malignant transformation, along with a deficiency in certain components of the innate immune system, may lead to serious consequences under conditions of inflammatory insult.