Lipopolysaccharide Production Research Articles

A short novel antimicrobial peptide BP100-W with antimicrobial, antibiofilm and anti-inflammatory activities designed by replacement with tryptophan

BP100 is a short cationic antimicrobial peptide (AMP) designed using a combinatorial chemistry approach based on the cecropin A-melittin hybrid. It displays potent antimicrobial activity against gram-negative bacteria and low toxicity toward eukaryotic cells. To develop a short AMP with potent cell selectivity, antibiofilm and anti-inflammatory activities, we designed a newly BP100 analog, BP100-W, in which Leu-3 at the hydrophobic face of BP100 was replaced by Trp. BP100-W possessed better cell selectivity, with a 1.7-fold higher therapeutic index than BP100. BP100-W displayed more effective synergistic activity when combined with several antibiotics, such as chloramphenicol, ciprofloxacin and oxacillin, compared to BP-100. BP100-W also exhibited stronger antibiofilm activity than BP100 in inhibiting biofilm formation by multidrug-resistant Pseudomonas aeruginosa (MDRPA) and eradicating the preformed biofilms of MDRPA. Moreover, unlike BP100, BP100-W significantly suppressed the production and expression of lipopolysaccharide (LPS)-induced pro-inflammatory cytokines, such as the tumor necrosis factor-α and nitric oxide. Boron-dipyrromethene-TR-cadaverine displacement assay demonstrated that the inhibitory activity of BP100-W on LPS-induced inflammation in RAW 264.7 cells may be due to increased direct interaction with LPS. Our results suggest that BP100-W exhibits potential for future use as an antimicrobial, antibiofilm and anti-inflammatory agent.

Pasture intake protects against commercial diet-induced lipopolysaccharide production facilitated by gut microbiota through activating intestinal alkaline phosphatase enzyme in meat geese.

Diet strongly affects gut microbiota composition, and gut bacteria can influence the intestinal barrier functions and systemic inflammation through metabolic endotoxemia. In-house feeding system (IHF, a low dietary fiber source) may cause altered cecal microbiota composition and inflammatory responses in meat geese via increased endotoxemia (lipopolysaccharides) with reduced intestinal alkaline phosphatase (ALP) production. The effects of artificial pasture grazing system (AGF, a high dietary fiber source) on modulating gut microbiota architecture and gut barrier functions have not been investigated in meat geese. Therefore, this study aimed to investigate whether intestinal ALP could play a critical role in attenuating reactive oxygen species (ROS) generation and ROS facilitating NF-κB pathway-induced systemic inflammation in meat geese. The impacts of IHF and AGF systems on gut microbial composition via 16 sRNA sequencing were assessed in meat geese. The host markers analysis through protein expression of serum and cecal tissues, hematoxylin and eosin (H&E) staining, localization of NF-қB and Nrf2 by immunofluorescence analysis, western blotting analysis of ALP, and quantitative PCR of cecal tissues was evaluated. In the gut microbiota analysis, meat geese supplemented with pasture showed a significant increase in commensal microbial richness and diversity compared to IHF meat geese demonstrating the antimicrobial, antioxidant, and anti-inflammatory ability of the AGF system. A significant increase in intestinal ALP-induced Nrf2 signaling pathway was confirmed representing LPS dephosphorylation mediated TLR4/MyD88 induced ROS reduction mechanisms in AGF meat geese. Further, the correlation analysis of top 44 host markers with gut microbiota showed that artificial pasture intake protected gut barrier functions via reducing ROS-mediated NF-κB pathway-induced gut permeability, systemic inflammation, and aging phenotypes. In conclusion, the intestinal ALP functions to regulate gut microbial homeostasis and barrier function appear to inhibit pro-inflammatory cytokines by reducing LPS-induced ROS production in AGF meat geese. The AGF system may represent a novel therapy to counteract the chronic inflammatory state leading to low dietary fiber-related diseases in animals.

Coumaronochromones, flavanones, and isoflavones from the twigs and leaves of Erythrina subumbrans inhibit PTP1B and nitric oxide production

A chemical investigation of the twigs and leaves of Erythrina subumbrans led to the isolation and structural elucidation of three coumaronochromones, erythrinasubumbrin A and (±)-erythrinasubumbrin B, five prenylated flavanones, (±)-erythrinasubumbrin C and erythrinasubumbrins D–F, and two prenylated isoflavones, (±)-5,4ʹ-dihydroxy-[4,5-cis-4-ethoxy-5-hydroxy-6,6-dimethyl-4,5-dihydropyrano (2,3:7,6)]-isoflavone, in addition to 18 known analogues. Two extra cinnamylphenols previously only known as commercial synthetic products were also isolated and elucidated from a natural source for the first time, and assigned the trivial names erythrinasubumbrins G and H. Their structures were characterized by detailed analysis of spectroscopic data, including HRESIMS and 2D NMR. The absolute configurations of the previously undescribed isolates and the known coumaronochromone lupinol C were determined by specific rotation and electronic circular dichroism (ECD) data. All the isolates were evaluated for their inhibitory activities on protein tyrosine phosphatase 1 B (PTP1B) and nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglial cells as well as their cytotoxicity against the HCT116 cell line. The pair of enantiomers, (+)-5,4ʹ-dihydroxy-[4,5-cis-4-ethoxy-5-hydroxy-6,6-dimethyl-4,5-dihydropyrano (2,3:7,6)]-isoflavone and (−)-5,4ʹ-dihydroxy-[4,5-cis-4-ethoxy-5-hydroxy-6,6-dimethyl-4,5-dihydropyrano (2,3:7,6)]-isoflavone, and the known compounds lupinol C, 4ʹ-O-methyl-8-prenylnaringenin, glepidotin B, shuterin, parvisoflavones A, luteone, lupiwighteone, 2,3-dehydrokievitone, 6,8-diprenylgenistein, angustone A, and 2ʹ-O-demethylbidwillol B exhibited different levels of PTP1B inhibitory activities with IC50 values ranging from 3.21 to 19.17 μM, while erythrinasubumbrin A, (−)-erythrinasubumbrin B, (+)-5,4ʹ-dihydroxy-[4,5-cis-4-ethoxy-5-hydroxy-6,6-dimethyl-4,5-dihydropyrano (2,3:7,6)]-isoflavone, (−)-5,4ʹ-dihydroxy-[4,5-cis-4-ethoxy-5-hydroxy-6,6-dimethyl-4,5-dihydropyrano (2,3:7,6)]-isoflavone, and the known compounds lupinol C, 8-prenylnaringenin, macatrichocarpin A, alpinumisoflavone, and 2ʹ-O-demethylbidwillol B substantially inhibited NO production in BV-2 microglial cells. In addition, 8-prenylnaringenin showed weak cytotoxicity with an IC50 value of 9.13 μM. This is the first report of PTP1B inhibitory activity for a coumaronochromone.

Iridoid Glycosides and Flavonoids Isolated from the Twigs and Leaves of Callicarpa nudiflora and Their Anti-Inflammatory Activities.

A new iridoid glycoside, named 6'-O-trans-feruloyl-8-epiloganic acid, together with fifteen known compounds were isolated from the twigs and leaves of Callicarpa nudiflora, a traditional Chinese medicine to treat inflammatory-related diseases. Their structures were identified by comprehensive spectroscopic analysis and comparison with reported data. Bioassay results revealed that twelve of the isolates could obviously inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cell lines with IC50 values from 0.64 to 38.72 μM. Among them, compounds 1 (3.27 μM), 6 (5.23 μM), 13 (1.56 μM) and 14 (0.64 μM) exhibited significantly higher activities than that of the positive control (27.13 μM). Additionally, it was supposed that the presence of the carboxy group at the C-4 position of iridoid glycosides and glycosylation at C-3 position of flavonoids might impact their inhibitory activities against NO production.

Characterisation of cytotoxicity and immunomodulatory effects of glycolipid biosurfactants on human keratinocytes

Skin irritation and allergic reactions associated with the use of skincare products formulated with synthetically derived surfactants such as sodium lauryl ether sulphate (SLES) have encouraged the search for naturally derived and biocompatible alternatives. Glycolipid biosurfactants such as sophorolipids (SL) and rhamnolipids (RL) offer a potential alternative to SLES. However, most studies on the bioactive properties of microbial glycolipids were determined using their mixed congeners, resulting in significant inter-study variations. This study aims to compare the effects of highly purified SL (acidic and lactonic) and RL (mono-RL and di-RL) congeners and SLES on a spontaneously transformed human keratinocyte cell line (HaCaT cells) to assess glycolipids’ safety for potential skincare applications. Preparations of acidic SL congeners were 100% pure, lactonic SL were 100% pure, mono-RL were 96% pure, and di-RL were 97% pure. Cell viability using XTT assays, cell morphological analyses, and immunoassays revealed that microbial glycolipids have differing effects on HaCaT cells dependent on chemical structure. Compared with SLES, acidic SL and mono-RL have negligible effects on cell viability, cell morphology, and production of pro-inflammatory cytokines. Furthermore, at non-inhibitory concentrations, di-RL significantly attenuated IL-8 production and CXCL8 expression while increasing IL-1RA production and IL1RN expression in lipopolysaccharide-stimulated HaCaT cells. Although further studies would be required, these results demonstrate that as potential innocuous and bioactive compounds, microbial glycolipids could provide a substitute to synthetic surfactants in skincare formulations and perform immunopharmacological roles in topical skin infections such as psoriasis.Key points• Purified glycolipid congeners have differing effects on human keratinocytes.• Compared with SLES, acidic sophorolipids and mono-rhamnolipids have innocuous effects on keratinocytes.• Di-rhamnolipids and mono-rhamnolipids modulate cytokine production in lipopolysaccharide stimulated human keratinocytes.

Phytochemicals and Antidiabetic, Antioxidant and Anti-inflammatory Activities of Ethanol Flower Extract of Syzygium aromaticum (L.) Merr. & Perry (Myrtaceae)

Syzygium aromaticum (L.) Merr. & Perry is a spice that has been used traditionally for centuries to preserve food and treat for a number of ailments. This research was carried out to analyze phytochemicals and to determine antidiabetic, antioxidant and anti-inflammatory activities of 95 % ethanol flower extract from S. aromaticum (FESA). The GC-MS analysis demonstrated the presence of 17 bioactive compounds in FESA, with eugenol (56.17 %) the most active compound. Antidiabetic activity study revealed that the inhibitory activity of the FESA against α-glucosidase enzyme was stronger than the activity of Acarbose, an antidiabetic drug. In addition, the FESA exhibited potent antioxidant activity by inhibiting 2, 2- diphenyl-1-picrylhydrazylhydrate (DPPH) free radicals higher than butylated hydroxyltoluene (BHT), a synthetic antioxidant. Furthermore, the FESA potentially inhibited the nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells but less effective than Diclofenac, a non-steroidal anti-inflammatory drug. The activities of FESA are partly due to the presence of active compounds. The results obtained confirm the antidiabetic, antioxidant and anti-inflammatory properties, and the traditional used of S. aromaticum for the treatment of diabetes and oxidative and inflammatory-related diseases. HIGHLIGHTS The most predominant bioactive compound in FESA is eugenol (56.17 %), analyzed by GC-MS FESA inhibits α-glucosidase activity significantly higher than acarbose, an antidiabetic drug. The FESA is therefore helpful to delay or possibly prevent the development of the diabetic complication The FESA exhibits DPPH radical scavenging activity is more potent than BHT, an antioxidant compound The FESA can provide a novel natural anti- inflammatory agent resource, as evidenced by the inhibitory effect of FESA on nitric oxide (NO) production GRAPHICAL ABSTRACT

Polypunctosides E-K: seven new steroidal saponins from Polygonatum punctatum Royle ex Kunth and their nitric oxide production inhibitory activities.

Polygonatum punctatum Royle ex Kunth is a high-value medicinal plant found in old natural forests. A phytochemical study on the roots of this plant led to the isolation of seven new steroidal saponins including four furostans (1-4) and three furospirostans (5-7). Their structures were elucidated as (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-3β,17α,22α,26-tetraol 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (1), (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-3β,14α,17α,22α,26-pentaol 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (2), (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-22α-methoxy-3β,17α,26-triol 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (3), (25R)-26-O-(β-D-glucopyranosyl)-furost-5-ene-22α-methoxy-3β,17α,26-triol 3-O-[α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)]-[acetoxy-(→ 6)]-β-D-galactopyranoside (4), 26-O-(β-D-glucopyranosyl)-14α,17α-dihydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (5), 26-O-(β-D-glucopyranosyl)-17α-hydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (6), and 26-O-(β-D-glucopyranosyl)-14α-hydroxynuatigenin 3-O-α-L-arabinopyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 4)-β-D-galactopyranoside (7) by extensive spectroscopic analyses, including infrared, high-resolution electrospray ionization mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectroscopy. Compounds 1-7 inhibited nitric oxide production in lipopolysaccharide activated RAW264.7 cells with IC50 values ranging from 41.5 ± 3.2 to 62.2 ± 3.7µM, compared to 33.8 ± 2.6µM for the positive control compound L-NMMA.

3ʹ,4ʹ-Dihydroxyflavone mitigates inflammatory responses by inhibiting LPS and TLR4/MD2 interaction

BackgroundWe previously reported the potential inhibitory activity of 3ʹ,4ʹ-dihydroxyflavone (DHF) on nitric oxide (NO) and prostaglandin E2 (PGE2) production in lipopolysaccharide (LPS)-stimulated macrophages. PurposeWe investigated the underlying molecular mechanisms of DHF in LPS-activated macrophages and evaluated its effect on LPS-induced septic shock in mice. MethodsTo explore the anti-inflammatory effect of DHF, nitrite, PGE2, and cytokines were measured in vitro and in vivo experiments. In addition, to verify the molecular signaling pathway, quantitative real time-PCR, luciferase assay, nuclear extraction, electrophoretic mobility shift assay, immunocytochemistry, immunoprecipitation, molecular docking analysis, and myeloid differentiation 2 (MD2)-LPS binding assay were conducted. ResultsDHF suppressed the LPS-induced expression of proinflammatory mediators through nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and interferon regulatory factor 3 (IRF3) inactivation pathways in RAW 264.7 macrophages. Importantly, molecular docking analysis and in vitro binding assays showed that DHF interacts with the hydrophobic pocket of MD2 and then interferes with the interaction between LPS and toll-like receptor 4 (TLR4). DHF inhibited LPS-induced oxidative stress by upregulating nuclear factor erythroid 2-related factor 2 (Nrf2). Treatment of LPS-induced endotoxemia mice with DHF reduced the expression levels of pro-inflammatory mediators via the inactivation of NF-κB, AP-1, and signal transducer and activator of transcription 1 (STAT1) in the lung tissue, thus increasing the survival rate. ConclusionTaken together, our data first time revealed the underlying mechanism of the DHF-dependent anti-inflammatory effect by preventing LPS from binding to the TLR4/MD2 complex. Therefore, DHF may be a possible anti-inflammatory agent for the treatment of LPS-mediated inflammatory diseases.

Camel Grass Phenolic Compounds: Targeting Inflammation and Neurologically Related Conditions.

The use of plants for therapeutic purposes has been supported by growing scientific evidence. This work consisted of (i) characterizing the phenolic compounds present in both aqueous and hydroethanol (1:1, v/v) extracts of camel grass, by hyphenated liquid chromatographic techniques, (ii) evaluating their anti-inflammatory, antioxidant, and neuromodulation potential, through in vitro cell and cell-free models, and (iii) establishing a relationship between the chemical profiles of the extracts and their biological activities. Several caffeic acid and flavonoid derivatives were determined in both extracts. The extracts displayed scavenging capacity against the physiologically relevant nitric oxide (•NO) and superoxide anion (O2•-) radicals, significantly reduced NO production in lipopolysaccharide (LPS)-stimulated macrophages (RAW 264.7), and inhibited the activity of hyaluronidase (HAase), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Some of these bioactivities were found to be related with the chemical profile of the extracts, namely with 3-caffeoylquinic, 4-caffeoylquinic, chlorogenic, and p-coumaric acids, as well as with luteolin and apigenin derivatives. This study reports, for the first time, the potential medicinal properties of aqueous and hydroethanol extracts of camel grass in the RAW 264.7 cell model of inflammation, and in neurologically related conditions.

Anti-Inflammatory, Antioxidative, and Nitric Oxide-Scavenging Activities of a Quercetin Nanosuspension with Polyethylene Glycol in LPS-Induced RAW 264.7 Macrophages

Quercetin (Qu) is a dietary antioxidant and a member of flavonoids in the plant polyphenol family. Qu has a high ability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) molecules; hence, exhibiting beneficial effects in preventing obesity, diabetes, cancer, cardiovascular diseases, and inflammation. However, quercetin has low bioavailability due to poor water solubility, low absorption, and rapid excretion from the body. To address these issues, the usage of Qu nanosuspensions can improve physical stability, solubility, and pharmacokinetics. Therefore, we developed a Qu and polyethylene glycol nanosuspension (Qu-PEG NS) and confirmed its interaction by Fourier transform infrared analysis. Qu-PEG NS did not show cytotoxicity to HaCaT and RAW 264.7 cells. Furthermore, Qu-PEG NS effectively reduced the nitrogen oxide (NO) production in lipopolysaccharide (LPS)-induced inflammatory RAW 264.7 cells. Additionally, Qu-PEG NS effectively lowered the levels of COX-2, NF-κB p65, and IL-1β in the LPS-induced inflammatory RAW 264.7 cells. Specifically, Qu-PEG NS exhibited anti-inflammatory properties by scavenging the ROS and RNS and mediated the inhibition of NF-κB signaling pathways. In addition, Qu-PEG NS had a high antioxidant effect and antibacterial activity against Escherichia coli and Bacillus cereus. Therefore, the developed novel nanosuspension showed comparable antioxidant, anti-inflammatory, and antibacterial functions and may also improve solubility and physical stability compared to raw quercetin.

C19-Diterpenoid alkaloids from Aconitum richardsonianum

Three new aconitine-type C 19 -diterpenoid alkaloids, richardsonines A-C ( 1–3 ), were isolated from the roots of Aconitum richardsonianum Lauener, together with seventeen known compounds ( 4–20 ). Their structures were elucidated by extensive spectroscopic analysis, and the absolute stereochemistry of 1 was confirmed by X-ray crystallography. Compounds 2 , 5 , 8 and 9 were rare C 19 -diterpenoid alkaloids bearing an OH group at C-16. Isolated compounds were evaluated for inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated neuroinflammatory responses in BV-2 microglial cells. Compounds 3 and 7 showed weak antineuroinflammatory effects with inhibition rates of 35.32 ± 2.29% and 39.94 ± 2.50%, respectively, at a concentration of 100 µM. • Three new diterpenoid alkaloids were isolated from A. richardsonianum . • Richardsonine B is a rare C 19 -diterpenoid alkaloid bearing a C 16 -OH moiety. • The antineuroinflammatory effects of the isolated compounds were evaluated.

CRISPR/Cas9 based blockade of IL-10 signaling impairs lipid and tissue homeostasis to accelerate atherosclerosis.

Interleukin-10 (IL-10) is a widely recognized immunosuppressive factor. Although the concept that IL-10 executes an anti-inflammatory role is accepted, the relationship between IL-10 and atherosclerosis is still unclear, thus limiting the application of IL-10-based therapies for this disease. Emerging evidence suggests that IL-10 also plays a key role in energy metabolism and regulation of gut microbiota; however, whether IL-10 can affect atherosclerotic lesion development by integrating lipid and tissue homeostasis has not been investigated. In the present study, we developed a human-like hamster model deficient in IL-10 using CRISPR/Cas9 technology. Our results showed that loss of IL-10 changed the gut microbiota in hamsters on chow diet, leading to an increase in lipopolysaccharide (LPS) production and elevated concentration of LPS in plasma. These changes were associated with systemic inflammation, lipodystrophy, and dyslipidemia. Upon high cholesterol/high fat diet feeding, IL-10-deficient hamsters exhibited abnormal distribution of triglyceride and cholesterol in lipoprotein particles, impaired lipid transport in macrophages and aggravated atherosclerosis. These findings show that silencing IL-10 signaling in hamsters promotes atherosclerosis by affecting lipid and tissue homeostasis through a gut microbiota/adipose tissue/liver axis.

Chemical constituents and their anti-neuroinflammatory activities from the bark of Taiwan incense cedar, Calocedrus formosana

One undescribed C40 terpenoid, calomacroquinoic acid; four undescribed diterpenes, 5α,6α-epoxy-7α-hydroxyferruginol, 15-ethoxysugiol, 7-methoxy-6,7-secoabieta-8,11,13-triene-6,12-diol, and ethyl 7,8-secoabieta-11,14-dioxo-7-ate; two compounds isolated from Nature for the first time, 6β,7α-dihydroxyferruginol and 12-O-methyltaxochinon; and six known compounds were successfully identified from the bark of Taiwan incense cedar Calocedrus formosana. Structures of all isolates were elucidated by physical data (appearance, ultraviolet, infrared, specific rotation, and X-ray) and spectroscopic data (1D and 2D nuclear magnetic resonance, and high-resolution electron ionization mass spectrometry). The biosynthetic pathway of calomacroquinoic acid is also described in the current study. Nitric oxide production in lipopolysaccharide (LPS)-stimulated BV-2 microglia cells was inhibited by 6,7-dehydroferruginol, 7α,11-dihydroxy-12-methoxy-8,11,13-abietriene, and trans-communic acid. Altogether, the bark of C. formosana possessed several potential natural therapeutics against inflammation-related neuronal diseases.

Sesquiterpene coumarins isolated from Ferula bungeana and their anti-neuroinflammatory activities

This is the first study to profile natural sesquiterpene coumarins (SCs) in Ferula bungeana, a medicinal plant of the genus Ferula in China. Eight undescribed sesquiterpene coumarins (1–8), along with six known ones (9–14) were obtained from the whole plant of F. bungeana. These unreported SCs (1–8) enriched the structural diversity of natural SCs, especially these with the hydroxy or carbonyl group at C-7′ and a hydroperoxy group at C-7′ or C-8′. Compounds (9–14) were reported for the first time from this plant. The in vitro anti-neuroinflammatory activity assay showed that compounds 2 and 9 showed stronger inhibitory effect on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced BV-2 microglia, compared with positive control minocycline, and compounds 5 and 10 showed moderate inhibitory effects.

Phialocetones A-J, C12 lactones from the rhizospheric soil-derived fungus Phialocephala sp. YUD18001 associated with Gastrodia elata

Ten undescribed C12 polyketide phialocetones A-J, featuring twelve-, six- and five-membered lactone moieties, were isolated from a rhizospheric soil-derived Phialocephala sp. YUD18001 associated with Gastrodia elata. Their structures were established by NMR spectroscopic analysis and HRMS, while their absolute configurations were determined by computational methods and chemical reactions. All isolated compounds were evaluated for their anti-inflammatory and cytotoxic activities. As a result, phialocetone D exhibited moderate effects against NO production in lipopolysaccharide (LPS)-induced RAW264.7 cells with an IC50 value of 14.77 μM, while phialocetone E showed cytotoxicity against HL-60 and SW480 cell lines with IC50 values of 19.04 and 10.22 μM, respectively.

Putative transcription antiterminator RfaH contributes to Erwinia amylovora virulence.

The gram‐negative bacterium Erwinia amylovora causes fire blight disease of apple and pear trees. The exopolysaccharide amylovoran and lipopolysaccharides are essential E. amylovora virulence factors. Production of amylovoran and lipopolysaccharide is specified in part by genes that are members of long operons. Here, we show that full virulence of E. amylovora in apple fruitlets and tree shoots depends on the predicted transcription antiterminator RfaH. RfaH reduces pausing in the production of long transcripts having an operon polarity suppressor regulatory element within their promoter region. In E. amylovora, only the amylovoran operon and a lipopolysaccharide operon have such regulatory elements within their promoter regions and in the correct orientation. These operons showed dramatically increased polarity in the ΔrfaH mutant compared to the wild type as determined by RNA sequencing. Amylovoran and lipopolysaccharide production in vitro was reduced in rfaH mutants compared to the wild type, which probably contributes to the rfaH mutant virulence phenotype. Furthermore, type VI secretion cluster 1, which contributes to E. amylovora virulence, showed reduced expression in ΔrfaH compared to the wild type, although without an increase in polarity. The data suggest that E. amylovora RfaH directly, specifically, and exclusively suppresses operon polarity in the amylovoran operon and a lipopolysaccharide operon.

Pterostilbene attenuates intestinal epithelial barrier loss induced by high loading intensity of exercise.

Mounting evidence suggested that high loading intensity of exercise might be detrimental to human health, especially the gastrointestinal tract. Pterostilbene (PTE), derived from grapes and blueberries, might reach a high concentration of intestinal contents. Our study aimed to evaluate PTE’s ability to prevent the loss of intestinal epithelial barrier in high loading intensity of exercise. The exercise model was established by the forced running of mice. An effective HPLC-UV method was developed to quantify PTE concentration in intestinal content. The mRNA changes were detected by quantitative polymerase chain reaction (qPCR). The structure of intestinal flora was analyzed by 16S rRNA sequencing. The PTE (100 mg/kg/d) could significantly attenuate exercise-induced intestinal epithelial barrier loss. Moreover, the HPLC-UV assay showed that the PTE concentration of intestinal content could last 12 h. Furthermore, the exercise increased the abundance of Alistipes, which was related to lipopolysaccharide (LPS) production but could not be reversed by PTE intervention. Besides, cell experiments showed that PTE could promote the expression of intestinal epithelial tight junction (TJ) molecules in vitro. In conclusion, PTE has a significant interest in preventing exercise-induced intestinal damage.

High-fat diet and alcohol induced-mice could cause colonic injury through molecular mechanisms of endogenous toxins.

Due to the complexity and diverse causes, the pathological mechanism of diet-induced colonic injury and colitis remains unclear. In this study, we studied the effects of the combination of a high-fat diet (HFD) plus alcohol on colonic injury in mice. We found HFD plus alcohol treatment induced disturbance of the gut microbiota; increased the production of intestinal toxins lipopolysaccharide (LPS), indole, and skatole; destroyed the stability of the intestinal mucosa; and caused the colonic epithelial cells damage through the activation of nuclear factor (NF)-κB and aromatic hydrocarbon receptors (AhR) signaling pathways. To mimic the effect of HFD plus alcohol in vivo, NCM460 cells were stimulated with alcohol and oleic acid with/without intestinal toxins (LPS, indole, and skatole) in vitro. Combinative treatment of alcohol and oleic acid caused moderate damage on NCM460 cells, while combination with intestinal toxins induced serious cell apoptosis. Western blot data indicated that the activation of NF-κB and AhR pathways further augmented after intestinal toxins treatment in alcohol- and oleic acid-treated colonic cells. This study provided new evidence for the relationship between diet pattern and colonic inflammation, which might partly reveal the pathological development of diet-induced colon disease and the involvement of intestinal toxins.

Khaya grandifoliola active fraction as a source of therapeutic compounds for Alzheimer's disease treatment: In silico validation of identified compounds.

Overproduction of Nitric oxide (NO) and many other pro-inflammatory mediators are responsible for many pathological disorders in humans, including Alzheimer's disease (AD). In this study, active fractions isolated from Khaya grandifoliola (Kg) were screened for their inhibitory activities against NO production in lipopolysaccharide (LPS)-activated microglia. Among the 5 fractions tested, Kg25 was the most active and showed potent inhibitory activity towards NO production. The fraction further showed inhibitory effect on iNOS's mRNA expression and other major pro-inflammatory cytokines including TNFα and IL1-β. Study of the effect of Kg25 on p38MAPKinase and JNK3 showed that the fraction inhibits these signaling pathways known to be involved in cell inflammatory pathways. These observations were confirmed at the protein level with Kg25 inhibiting iNOS and p38MAPK protein expressions in N9 cells. Analysis of Kg25 composition by HPLC identified 3 main compounds, namely: 6 phenyl, 4-(1`oxyehylphenyl) hexane, Carbamic acid, (4-methly-1-phenyl)-1, phenyl, and Benzene, 1 1`-(oxydiethylidene) bis. The above mentionned compounds were further analyzed for their bioactivity against the p38MAPKinase and iNOS receptors using molecular docking. MolDock results showed that 1-phenylethylN-(4-methylphenyl)carbamate (compound 2) possesses the highest binding affinity (for iNOS); and 1-(1-phenylethoxy)ethylbenzene (compound 3) (for pMAPK) respectively and both compounds interact well with the active site residues. Hence, these compounds could be considered as scaffolds for further development of lead- drugs targeting neuroinflammation in AD.

Unusual sesquilignans with anti-inflammatory activities from the resin of Ferula sinkiangensis

Sinkianlignans A − D (1–4), four new sesquilignans with an unusual architectures was characterized with a rarely α-γ′, β-γ′, and γ-γ′ linkage pattern, and sinkianlignans E − F (5 and 6), two lignans, were isolated from the Ferula sinkiangensis. Hypothetic biosynthetic pathway of compound 3 contain a newly formed six-membered C-ring by Diels-Alder cycloaddition. The structures of isolates were established by spectroscopic techniques and computational methods. Biological evaluation of all the isolated compounds revealed that compounds 2a and 2b could inhibit IL-6 and TNF-α production in lipopolysaccharide (LPS) induced RAW264.7 cells in a dose-dependent manner.