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Insects can assemble defensive microbiomes on their body surfaces to defend against fungal parasitic infections. The strategies employed by fungal pathogens to combat host cuticular microbiotas remains unclear. Here, we report the identification and functional characterization of the defensin-like antimicrobial gene BbAMP1 encoded by the entomopathogenic fungus Beauveria bassiana. The mature peptide of BbAMP1 can coat fungal spores and can be secreted by the fungus to target and damage Gram-positive bacterial cells. Significant differences in insect survival were observed between the wild-type and BbAMP1 mutant strains during topical infection but not during injection assays that bypassed insect cuticles. Thus, BbAMP1 deletion considerably reduced fungal virulence while gene overexpression accelerated the fungal colonization of insects compared with the wild-type strain in natural infections. Topical infection of axenic Drosophila adults evidenced no difference in fly survivals between strains. However, the gnotobiotic infections with the addition of Gram-positive but not Gram-negative bacterial cells in fungal spore suspensions substantially increased the survival of the flies treated with ∆BbAMP1 compared to those infected by the wild-type and gene-overexpression strains. Bacterial colony counts and microbiome analysis confirmed that BbAMP1 could assist the fungus to manipulate insect surface bacterial loads. This study reveals that fungal defensin can suppress the host surface defensive microbiomes, which underscores the importance to extend the research scope of fungus-host interactions.

Graphical Abstract Stimulus-responsive therapy that allows precise imaging-guided therapy is limited for osteoarthritis (OA) therapy due to the selection of proper physiological markers as stimulus. Based on that the over-production of Reactive Oxygen Species (ROS) is associated with the progression in OA, we selected ROS as markers and designed a cartilage targeting and ROS-responsive theranostic nanoprobe that can be used for effective bioimaging and therapy of OA. This nanoprobe was fabricated by using PEG micelles modified with ROS-sensitive thioketal linkers (TK) and cartilage-targeting peptide, termed TKCP, which was then encapsulated with Dexamethasone (DEX) to form TKCP@DEX nanoparticles. Results showed that the nanoprobe can smartly “turn on” in response to excessive ROS and “turn off” in the normal joint. By applying different doses of ROS inducer and ROS inhibitor, this nanoprobe can emit ROS-dependent fluorescence according to the degree of OA severity, helpful to precise disease classification in clinic. Specifically targeting cartilage, TKCP@DEX could effectively respond to ROS and sustained release DEX to remarkably reduce cartilage damage in the OA joints. This smart, sensitive and endogenously activated ROS-responsive nanoprobe is promising for OA theranostics. Supplementary Information The online version contains supplementary material available at 10.1186/s12951-021-01136-4.

IntroductionDiabetic erectile dysfunction (DMED) refers to erectile dysfunction secondary to diabetes. Erectile dysfunction is characterized by a persistent inability to achieve and maintain an erection sufficient to permit satisfactory sexual activity.MethodsBased on the Web of Science core collection database, we firstly analyzed the quantity and quality of publications in the field of DMED, secondly profiled the publishing groups in terms of country, institution, author’s publication and cooperation network, and finally sorted out and summarized the hot topics of research.ResultsFrom 2001 to 2022, a total of 1,403 articles relating to this topic were published in 359 journals. They represent the global research status, potential hotspots, and future research directions. The number of DMED-related publications and citations has steadily increased over the few past decades. Academic institutions from Europe and the United States have played a leading role in DMED research. The country, institution, journal, and author with the most publications were the United States (294), INHA University (39), the Journal of Sexual Medicine (156), and Ryu, Ji-Kan (29), respectively. The most common keywords were erectile dysfunction (796), men (256), diabetes (254), diabetes mellitus (239), prevalence (180), corpus cavernosum (171), dysfunction (155), mellitus (154), nitric-oxide synthase (153), and expression (140). The main keyword-based research topics and hotspots in the DMED field were oral sildenafil, smooth muscle relaxation, nitric oxide synthase, gene therapy, metabolic syndrome, cavernous nerve injury, stem cell, and penile prosthesis.DiscussionThe terms oral sildenafil, smooth muscle relaxation, nitric oxide synthase, gene therapy, metabolic syndrome, cavernous nerve injury, stem cell, and penile prosthesis will be at the forefront of DMED-related research.

Emerging evidence has shown that the plant and animal surface microbiomes can defend hosts against fungal parasite infections. The strategies employed by fungal pathogens to combat the antagonistic inhibition of insect surface bacteria are still elusive. In this study, we found that the potent antibiotic helvolic acid (HA) produced by the insect pathogen Metarhizium robertsii contributes to natural fungal infection of insect hosts. Antibiotic and gnotobiotic infection assays confirmed that HA could facilitate fungal infection of insects by suppression of the host cuticular microbiomes through its bacteriostatic instead of bactericidal activities. The data from this study provide insights into the novel chemical biology of fungal secondary metabolisms.

The effects of dietary chitosan (0, 2, 4, 6, 8 and 10 g/kg) on the growth, health condition and disease resistance of golden pompano Trachinotus ovatus were evaluated. Dietary chitosan significantly enhanced weight gain, with the highest observed in fish fed the 6 g/kg chitosan diet. This chitosan level significantly promoted gut health by increasing villus length, lipase and protease activities and intestinal barrier-related genes expression. Meanwhile, dietary 6 g/kg chitosan improved the inflammatory response and anti-oxidative capacity of fish by regulating the expression of genes involved in NF-κB pathway and Nrf2 pathway, respectively. Furthermore, after challenge with Vibrio harveyi for 2 weeks, the survival rate increased significantly when dietary chitosan level was 6 g/kg. Overall, our results indicate that 6 g/kg chitosan is the optimal dose for enhancing growth, health and disease resistance of fish, but excessive chitosan (10 g/kg) weakens its beneficial effects.

As the most abundant marine carotenoid extracted from seaweeds, fucoxanthin is considered to have neuroprotective activity via its excellent antioxidant properties. Oxidative stress is regarded as an important starting factor for neuronal cell loss and necrosis, is one of the causes of Parkinson’s disease (PD), and is considered to be the cause of adverse reactions caused by the current PD commonly used treatment drug levodopa (l-DA). Supplementation with antioxidants early in PD can effectively prevent neurodegeneration and inhibit apoptosis in dopaminergic neurons. At present, the effect of fucoxanthin in improving the adverse effects triggered by long-term l-DA administration in PD patients is unclear. In the present study, we found that fucoxanthin can reduce cytotoxicity and suppress the high concentration of l-DA (200 μM)-mediated cell apoptosis in the 6-OHDA-induced PC12 cells through improving the reduction in mitochondrial membrane potential, suppressing ROS over-expression, and inhibiting active of ERK/JNK-c-Jun system and expression of caspase-3 protein. These results were demonstrated by PD mice with long-term administration of l-DA showing enhanced motor ability after intervention with fucoxanthin. Our data indicate that fucoxanthin may prove useful in the treatment of PD patients with long-term l-DA administration.

Stimulus-responsive therapy permits precise control of therapeutic effect only at lesion of interest, which determines it a promising method for diagnosis and imaging-guided precision therapy. The acid environment and overexpressed matrix metalloproteinases-13 (MMP-13) are typical markers in osteoarthritis (OA), which enables the development of stimulus-responsive drug delivery system with high specificity for OA. We herein demonstrate a nano-micelle based stimuli-responsive theranostic strategy with reporting and drug release controlled by acidic pH and MMP-13 for OA therapy. Such nanoplatform is incorporated with a motif specifically targeting on cartilage, a motif responsive to matrix metalloproteinases-13 to specifically report OA condition and biodynamics of nano-micelles, an anti-inflammatory drug (e.g., psoralidin (PSO)) from traditional Chinese medicine, and a biocompatible polymeric skeleton for sustainable drug release in response to the acidic OA condition. The high effectiveness of this targeted precision therapy is demonstrated comprehensively by both in vitro and vivo evidences.

Monitoring cellular GSH dynamics is of great value to understand its complex biological functions and related diseases. It still remains challenging to understand the mechanism of GSH dynamics in complex intracellular environment. Herein, a novel fluorescent probe featured with chlorinated coumarin-TCF was exploited for sensing of GSH with high selectivity and high sensitivity. Large fluorescence enhancement at 471 nm was observed upon addition of GSH with large emission distance (Δλem = 219 nm). This novel probe was successfully applied to monitor endogenous and exogenous GSH dynamics without interference of other thiols via fluorescence imaging. More importantly, using this probe, low dose reactive oxygen species induced GSH increasement through nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signal pathway in BEL-7402 cells was observed. This novel fluorescent probe has the potential for quantitative monitoring of cellular GSH, which will promote further understanding of its physiological and pathological roles in biological systems.

Sulfites and other preservatives are considered food additives to prevent pathogen growth in food, and they are generally regarded as safe since the late 1950s. However, the possible effects of sulfites on potential damage to host intestinal tissue remain largely unexplored. Given that endogenous sulfite mainly comes from the metabolism of biothiol, we attempted to clarify the relationship among biothiol levels, gut and food additives sulfite, including sodium bisulfite (NaHSO

Studying numerous biologically important species simultaneously is crucial to understanding cellular functions and the root causes of related diseases. Direct visualization of endogenous biothiols in biological systems is of great value to understanding their biological roles. Herein, a novel multi-signal fluorescent probe was rationally designed and exploited for the simultaneous sensing of homocysteine (Hcy), cysteine (Cys), and glutathione (GSH) using different emission channels. This probe was successfully applied to the simultaneous discrimination between and visualization of endogenous Hcy, Cys, GSH, and their transformation in living cells.

Background：Alzheimer’s disease (AD) is a progressive, neurodegenerative disease of the brain. Serum homocysteine (Hcy) level is considered to be an important biomarker for AD, however, the status of Hcy in brain tissue and neuronal cells, and the association between brain and serum levels of Hcy in clinical AD patients currently remain unclear. Methods: The levels of Hcy and other biothiols such as cysteine (Cys) and glutathione (GSH) in clinical blood samples were evaluated using a non-cytotoxic and stable multi-signal fluorescent probe, ethyl (E)-3-(9-chloro-11-oxo-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f] pyrido[3,2,1 -ij]quinolin-10-yl)-2-cyanoacrylate (Probe 1), which were verified by ELISA. Results: Measurement by Probe 1 revealed a significant increase in Hcy level, and a decrease in Cys and GSH levels in PC12 cells treated with in Aβ1-42. The hippocampus and whole brain of APP/PS1 mice also showed a significant increase in Hcy level alongside the accumulation of age-related AD symptoms, while levels of Cys and GSH decreased simultaneously. This change was also observed in serum samples acquired from patients with AD. The upregulation of Hcy and the downregulation of Cys and GSH were reversed in the Aβ1-42-treated PC12 cells and the brain of APP/PS1 mice when supplemented with VB6, an important coenzyme in Hcy metabolism. Conclusions: Changes in Hcy, Cys and GSH levels in the brain of APP/PS1 mice and Aβ1-42-treated PC12 cells were observed in situ with a new fluorescent probe, which were consistent with the abnormal changes in Hcy, Cys and GSH levels in the serum of AD patients. VB6 supplementation was successful in ameliorating abnormal upregulation of Hcy in the brain of APP/PS1 mice and in Aβ1-42-treated PC12 cells.

As the most abundant marine carotenoid extracted from seaweeds, fucoxanthin (FUC) is considered to have excellent neuroprotective activity. However, the target of FUC for its neuroprotective properties remains largely unclear. Oxidative stress is one of the initiating factors causing neuronal cell loss and necrosis, and it is also an important inducement of Parkinson’s disease (PD). In the present study, the neuroprotective effect of FUC was assessed using a 6-hydroxydopamine- (6-OHDA-) induced neurotoxicity model. FUC suppressed 6-OHDA-induced accumulation of intracellular ROS, the disruption of mitochondrial membrane potential, and cell apoptosis through the Nrf2-ARE pathway. Keap1 as a repressor of Nrf2 can regulate the activity of Nrf2. Here, the biolayer interferometry (BLI) assay demonstrated that FUC specifically targeted Keap1 and inhibited the interaction between Keap1 and Nrf2. FUC bound to the hydrophobic region of Keap1 pocket and formed hydrogen bonding interactions with Arg415 and Tyr525. Besides, it also dose-dependently upregulated the expressions of antioxidant enzymes, such as nicotinamide heme oxygenase-1, glutamate-cysteine ligase modifier subunit, and glutamate-cysteine ligase catalytic subunit, in 6-OHDA-induced PC12 cells. In 6-OHDA-exposed zebrafish, FUC pretreatment significantly increased the total swimming distance of zebrafish larvae and improved the granular region of the brain tissue damage. These results suggested that FUC could protect the neuronal cells against 6-OHDA-induced injury via targeting Keap1.

A sensitive fluorescent probe (E)-4-(3-(benzo[d]thiazol-2-yl)-4-hydroxy-5-methylstyryl)-1-methylpyridin-1-ium iodide (HBTMP) for the monitoring of pH in mitochondria was rationally exploited. This novel probe exhibited remarkable pH-dependent behavior in the linear range of 5.5-8.0, along with a pKa value of 6.829 ± 0.02627. A large Stokes shift of 205 nm was obtained. This fluorescent probe demonstrated good biocompatibility and high sensitivity for detecting the dynamic changes in mitochondrial pH in living cells and zebrafish. The results of the CCCP (m-chlorophenyl hydrazone) treatment experiment indicated that the probe can effectively monitor changes in mitochondrial pH caused by cell damage.

Carrageenan (CGN) is a common food additive, and questions have been raised regarding its safety for human consumption. The purpose of this study was to investigate the impact of κ-CGN on glucose intolerance and insulin resistance from the perspective that κ-CGN may interfere with insulin receptor function and affect insulin sensitivity and signaling, thereby leading to body weight loss. The health effects of κ-CGN on C57BL/6 mice were assessed over a 90-d period by monitoring changes in body weight, glucose tolerance, insulin tolerance, fasting glucose and insulin levels, and expression of insulin-pathway-related proteins. Furthermore, HepG2 cells were used to detect the binding of κ-CGN on insulin receptor and measure its effect on downstream signal transduction. In mice, κ-CGN treatment reduced weight gain without affecting food intake. Glucose and insulin tolerance tests revealed that κ-CGN treatment increased blood glucose levels and glycosylated hemoglobin levels, while hepatic and muscle glycogen levels were decreased, suggesting that κ-CGN affected glucose metabolism in mice. Interestingly, κ-CGN treatment did not cause typical diabetic symptoms in mice, as indicated by low levels of fasting and postprandial blood glucose, in addition to normal pancreatic tissue and insulin secretion. The binding studies revealed that κ-CGN could competitively bind to the insulin receptor with FITC-insulin and thereby disrupt PI3K and Akt activation, thus suppressing expression of glucose transporters and glycogen synthase. In summary, this study revealed that κ-CGN reduced weight gain without affecting food intake, but impaired glucose metabolism in mice by interfering with insulin binding to receptors, thereby affecting the sensitivity of insulin and inhibiting the insulin PI3K/AKT signaling pathway, causing non-diabetic weight gain reduction.

Drug therapy of osteoarthritis (OA) is limited by the short retention and lacking of stimulus-responsiveness after intra-articular (IA) injection. The weak acid microenvironment in joint provides a potential trigger for controlled drug release systems in the treatment of OA. Herein, we developed an pH-responsive metal − organic frameworks (MOFs) system modified by hyaluronic acid (HA) and loaded with an anti-inflammatory protocatechuic acid (PCA), designated as MOF@HA@PCA, for the therapy of OA. Results demonstrated that MOF@HA@PCA could smartly respond to acidic conditions in OA microenvironment and gradually release PCA, which could remarkably reduce synovial inflammation in both IL-1β induced chondrocytes and the OA joints. MOF@HA@PCA also down-regulated the expression of inflammatory markers of OA and promoted the expression of cartilage-specific makers. This work may provide a new insight for the design of efficient nanoprobes for precision theranostics of OA .

Carotenoids consist of a series of conjugated isoprene units that are characteristically highly conjugated through double bonds, leading to the formation of many isomers that are susceptible to oxidation and other chemical modifications. Extreme hydrophobicity and high complexity make carotenoids difficult to identify and quantify. We implemented the use of a common Syncronis C18 column with strong eluting solvent, here isopropanol, to successfully separate a mixture of 23 carotenoids standards with different structural properties. In addition, the method differentiated between three groups of isomeric carotenoids (lycopene/δ-carotene/γ-carotene/e-carotene/α-carotene/β-carotene, α-cryptoxanthin/β-cryptoxanthin, and zeaxanthin/lutein) by optimizing the gradient profile and using liquid chrmatography-mass spectrometry. The LOD ranged from 0.05 to 5.51 ng/mL, and the recovery of carotenoids in Mytilus coruscus was from 63.54 to 93.25%, with standard deviations

RATIONALE The precise identification of carotenoid esters of Penaeus monodon, especially those in the carotenoid skeleton, needs to occur during mass spectrometry analysis. Detailed structural information about carotenoid esters is significant not only for the assessment of nutritional quality, but also for tracing biosynthetic precursors. METHODS The profiling of carotenoid esters in P. monodon was elucidated using ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC/Q-Orbitrap-HRMS). The raw LC/MS data were analyzed using Exact Finder™ software. RESULTS The structurally relevant ions, *l and *m, were considered markers of the astaxanthin monoester. Moreover, the carotenoid skeleton was unequivocally identified using the diagnostic ions *i, *j/*j' and *g/*g' generated by the carbon-carbon bond cleavage between β-ionone ketones and conjugated polyene moieties. In total, 24 carotenoid esters were identified in P. monodon based on the fragmentation patterns discussed above. The identified carotenoid skeleton includes astaxanthin, astacene, oxidized astaxanthin and adonixanthin, which have been described for the first time. CONCLUSIONS Characterization of the unknown carotenoid esters demonstrates the capabilities of this methodology, which is significant for enriching the carotenoid species in P. monodon.

For nearly half a century, the scientific community has been unable to agree upon the safety profile of carrageenan (CGN), a ubiquitous food additive. Little is known about the mechanisms by which consumption of CGN aggravates the etiopathogenesis of murine colitis. However, analyses of gut microbiota and intestinal barrier integrity have provided a breakthrough in explaining the synergistic effect of CGN upon colitis. In Citrobacter rodentium-induced infectious murine colitis, inflammation and the clinical severity of gut tissue were aggravated in the presence of λ-CGN. Using fecal transplantation and germ-free mice experiments, we evaluated the role of intestinal microbiota on the pro-inflammatory effect of λ-CGN. Mice with high dietary λ-CGN consumption showed altered colonic microbiota composition that resulted in degradation of the colonic mucus layer, a raised fecal LPS level, and a decrease in the presence of bacterially derived short-chain fatty acids (SCFAs). Mucus layer defects and altered fecal LPS and SCFA levels could be reproduced in germ-free mice by fecal transplantation from CGN-H-fed mice, but not from germ-free CGN-H-fed mice. Our results confirm that λ-CGN may create an environment that favors inflammation by altering gut microbiota composition and gut bacterial metabolism. The present study provides evidence that the "gut microbiota-barrier axis" could be an alternative target for ameliorating the colitis promoting effect of λ-CGN.

Natural astaxanthin is the strongest antioxidant ever discovered, with many biological functions, and it is widely used in the fields of health food and biomedical research. In the present study, we aimed to investigate the plasma concentration, distribution and safety of astaxanthin from Haematococcus pluvialis in pregnant mice. In the acute studies, the oral LD50 of astaxanthin was greater than 20 g/kg·bw. In mouse bone marrow micronucleus test, 10 g/kg·bw astaxanthin did not cause damage to chromosomes and mitotic apparatus of pregnant mice. After treatment with a single dose of 500 mg/kg·bw astaxanthin, the concentration of astaxanthin in plasma reached the maximum at 8 h (55.7 μg/L), which was completely metabolized after 48 h. In the repeat-dose toxicity test, 100, 250 and 500 mg/kg·bw astaxanthin showed no abnormalities in terms of body and organ weight as well as hematological and biochemical parameters in clinical observation throughout the pregnancy. During pregnancy, the liver accumulated the highest content of astaxanthin, while the eye exhibited the least. The results indicated that administration of astaxanthin from H. pluvialis throughout pregnancy had no adverse effect on mice.

Osteoarthritis (OA) microenvironment is marked by matrix metalloproteinases-13 (MMP-13) overexpression and weak acidity, making it possible to develop dual-stimuli responsive theranostic nanoprobes for OA diagnosis and therapy. However, current MMP/pH-responsive systems are not suitable for OA because of their poor biocompatibility, poor degradation and non-cartilage-targeting of the responsive probes. Here we designed a novel biocompatible cartilage-targeting and MMP-13/pH-responsive ferritin nanocages (CMFn) loaded with an anti-inflammatory drug (Hydroxychloroquine, HCQ), termed CMFn@HCQ, for OA imaging and therapy. We found that CMFn could be smartly "turned on" to emit light for OA imaging in response to the level of overexpressed MMP-13 in OA microenvironment, corresponding to the degree of OA severity. Thus the light intensity detected reflected the degree of OA severity, enabling the precise disease classification by our CMFn. CMFn could be "turned off" to stop emitting light in the normal joint. CMFn@HCQ nanocages could target the cartilage and release HCQ in the OA joint specifically under acidic pH conditions in a sustained manner, prolonging the drug retention time to 14 days to remarkably reduce synovial inflammation in the OA joints. The CMFn@HCQ nanocages represent a smart dual-stimuli responsive and cartilage-targeting nanoprobes, and hold promise for imaging-guided precision therapy for OA.

Intra-articular (IA) drug delivery to treat osteoarthritis (OA) is limited by the short retention time of drugs in the joints due to poor specific targeting and non-responsiveness under acidic environment. A cartilage-targeting peptide was engineered to the surface of ferritin nanocages (CT-Fn) and loaded with an anti-inflammatory drug, metformin (Met), via the self-assembling nature of Fn nanocages. It demonstrated that the CT-Fn/Met could specifically bind to type II collagen, leading to the downregulation of catabolic markers of OA and promotion of cartilage-specific makers in IL-1β-induced chondrocytes. IA delivery of CT-Fn/Met prolonged the retention time for 3 weeks and remarkably reduced inflammation. Moreover, better release under acidic conditions which enabling longer retention time of Met after IA delivery in OA joints for one more week. CT-Fn/Met could target and efficiently enter chondrocytes, further inducing prolonged IA accumulation and achieving enhanced therapeutic efficacy for OA treatment.

Nanofibers as niche-biomimetic scaffolds hold promise in guided bone regeneration (GBR). Here we fabricated poly (lactic-co-glycolic acid) (PLGA)/poly(caprolactone) (PCL)-doped octacalcium phosphate (OCP) nanofiber membranes via electrospinning and investigated the osteogenic behavior of marrow mesenchymal stem cells (MSCs) on the membranes. By adjusting different ratio of OCP to PLGA/PCL, three hybrid stents including PLGA/PCL, PLGA/PCL/2 wt%OCP, PLGA/PCL/4wt%OCP were successfully prepared. The PLGA/PCL/OCP membranes showed a decrease in fiber diameter compared with PLGA/PCL, leading to enhanced mechanical strength. In-vitro studies showed that PLGA/PCL/OCP membranes better supported cell adhesion, spreading and proliferation than PLGA/PCL. The incorporation of OCP via electrospinning also endowed the membranes with osteoinductive capacity, as evidenced by activation of ALP activity, increased gene expression of bone specific markers (such as Runx2, ALP, Col 1a1, OPN, OCN, BMP2), and mineral nodules formation compared to PLGA/PCL. Comparatively, PLGA/PCL/4wt%OCP showed better mechanical and biological performance than PLGA/PCL/2 wt%OCP, demonstrating the role of OCP in nanofiber membranes. Thus, the electrospun PLGA/PCL/OCP nanofiber membranes can be potentially developed as a promising hybrid stent for GBR.

Background Carrageenan (CGN), a high molecular weight sulfated polysaccharide, is a traditional ingredient used in food industry. Its degraded forms have been identified as potential carcinogens, although the mechanism remains unclear. Methods The effects of degraded λ-carrageenan (λ-dCGN) on murine RAW264.7 cells and human THP-1-derived macrophage cells were investigated by studying its actions on tumor necrosis factor alpha (TNF-α) secretion, Toll-like receptor 4 (TLR4) expression, and activation of nuclear factor-κb (NF-κB) and activation protein-1 (AP-1) pathways. Results We found that λ-dCGN was much stronger than native λ-CGN in the activation of macrophages to secrete TNF-α. Treatment of RAW264.7 cells with λ-dCGN resulted in the upregulation of TLR4, CD14 and MD-2 expressions, but it did not increase the binding of lipopolysacchride (LPS) with macrophages. Meanwhile, λ-dCGN treatment activated NF-κB via B-cell lymphoma/leukemia 10 (Bcl10) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) phosphorylation. In addition, λ-dCGN induced extracellular signal-regulated kinases/1/2/mitogen-activated protein kinases (ERK1/2/MAPK) and AP-1 activation. Interestingly, pretreatment of RAW264.7 cells with λ-dCGN markedly enhanced LPS-stimulated TNF-α secretion. This pretreatment resulted in the enhanced phosphorylation of ERK1/2 and c-Jun N-terminal kinase (JNK) and intensified activation of AP-1. Conclusions λ-dCGN induced an inflammatory reaction via both NF-κB and AP-1, and enhanced the inflammatory effect of LPS through AP-1 activation. General significance The study demonstrated the role of λ-dCGN to induce the inflammatory reaction and to aggravate the effect of LPS on macrophages, suggesting that λ-dCGN produced during food processing and gastric digestion may be a safety concern.

Exercise-induced reactive oxygen and nitrogen species are increasingly considered as beneficial health promotion. Astaxanthin (ASX) has been recognized as a potent antioxidant suitable for human ingestion. We investigated whether ASX administration suppressed antioxidant enzyme activity in moderate-intensity exercise. Seven-week-old male C57BL/6 mice (n = 8/group) were treated with ASX (5, 15, and 30 mg/kg BW) combined with 45 min/day moderate-intensity swimming training for four weeks. Results showed that the mice administrated with 15 and 30 mg/kg of ASX decreased glutathione peroxidase, catalase, malondialdehyde, and creatine kinase levels in plasma or muscle, compared with the swimming control group. Beyond that, these two (15 and 30 mg/kg BW) dosages of ASX downregulated gastrocnemius muscle erythroid 2p45 (NF-E2)-related factor 2 (Nrf2). Meanwhile, mRNA of Nrf2 and Nrf2-dependent enzymes in mice heart were also downregulated in the ASX-treated groups. However, the mice treated with 15 or 30 mg/kg ASX had increased constitutive nitric oxidase synthase and superoxide dismutase activity, compared with the swimming and sedentary control groups. Our findings indicate that high-dose administration of astaxanthin can blunt antioxidant enzyme activity and downregulate transcription of Nrf2 and Nrf2-dependent enzymes along with attenuating plasma and muscle MDA.

Previous studies indicated that fascaplysin derived from marine sponge can induce tumor cell death by apoptosis and possesses anti-angiogenesis activity. In order to verify these two effects in animal model and to identify action mechanisms, we established a sarcoma mice model, and treated mice with fascaplysin for 10 days. The tumor tissues were examined morphologically and immunohistochemically. The differential gene expression was also investigated by mRNA array. Fascaplysin treatment resulted in a significant suppression of tumor growth. Typical apoptotic phenomena were observed by transmission electron microscope and histological detection. Tissue sections were stained with monoclonal antibody directed to proliferating cell nuclear antigen (PCNA) and CD31. The decreased PCNA and CD31 antigen staining indicate the reduction of tumor cell proliferation and tumor vasculature property of fascaplysin in vivo. Microarrays were used to examine the gene expression profiles of tumors on CapitalBio mouse genome oligo array. The regulated genes analyzed from the expression level showed overlapping gene ontology (GO) categories and pathway mapping. Our findings indicate that cell cycle arrest, apoptosis, regulation of actin cytoskeleton, and cell adhesion all play important roles in the onset of fascaplysin. Detailed analysis by real time PCR of key genes confirmed the experimental results of microarrays. From these findings, it can be considered that fascaplysin can inhibit the growth of S180 cell implanted tumor, and the action mechanisms may involve in apoptosis, anti-angiogenesis, or cell cycle arrest.

Among marine bacteria isolated from the cytotoxic sponge Hymeniacidon perleve, one strain NJ6-3-1 classified as Pseudomonas sp. showed both cytotoxic and antimicrobial activities. Fatty acid analysis indicated that the bacterial strain consists mainly of C16:1, C16:0, C18:1, C18:0, C15:0, C14:0. One unusual 9,10-cyclopropane-C17:0 fatty acid and C26:0 also constitute major components, as well as the existence of squalene, the precursor of triterpenoids. The major metabolites in the culture broth were identified as alkaloids, including diketopiperazines and indole compounds, namely 3,6-diisopropylpiperazine-2,5-dione, 3-benzyl-3-isopropylpiperazine-2,5-dione, 3,6-bis-(2-methylpropyl)-piperazine-2,5-dione, indole-3-carboxaldehyde, indole-3-carboxylic acid methyl ester, indole-3-ethanol, and quinazoline-2,4-dione.

Chronic rejection is a major cause of graft dysfunction and retransplantation after liver allotransplantation. Recent studies have implicated humoral response in this chronic rejection reaction. However, the manner in which humoral response is activated has not been fully investigated. In the present study, we address this question using our previously established chronic allograft liver rejection model induced by low-dose immunosuppressive cyclosporine (CsA) following Dark Agouti (DA) to Brown Norway (BN) liver transplantation. High-level donor-specific antibodies (IgG1 isotype), C4d deposition and histological graft damage indicated the involvement of humoral rejection in this chronic rejection reaction. In vitro assay showed that alloantibodies from pre-sensitized BN recipients induced apoptosis of bile ductal cells isolated from donor livers and the production of pro-fibrosis factors (TGF-beta, PDGF and FGF). Statistical analysis showed that the serum level of IL-10 was positively correlated with that of donor-specific antibodies (IgG1 isotype). Blockade of IL-10 in vivo down-regulated the level of donor-specific antibodies and ameliorated the outcome of chronic rejection. This suggests that humoral response in chronic allograft liver rejection is associated with Th2 type cytokine IL-10 and that Th2 response might promote chronic rejection by inducing a humoral response.

Since angiogenesis is involved in initiating and promoting several diseases such as cancer and cardiovascular events, this study was designed to evaluate the anti-angiogenesis of low-molecular-weight (LMW), highly sulfated lambda-carrageenan oligosaccharides (lambda-CO) obtained by carrageenan depolymerization, by CAM (chick chorioallantoic membrane) model and human umbilical vein endothelial cells (HUVECs). Significant inhibition of vessel growth was observed at 200 microg/pellet. A histochemistry assay also revealed a decrease of capillary plexus and connective tissue in lambda-CO treated samples. lambda-CO inhibited the viability of cells at the high concentration of 1 mg/mL, whereas it affected the cell survival slightly (95%) at a low concentration (250 microg/mL), and HUVEC is the most sensitive to lambda-CO among three kinds of cells. Furthermore, the inhibitory action of lambda-CO was also observed in the endothelial cell invasion and migration at relatively low concentration (150-300 microg/mL), through down-regulation of intracellular matrix metalloproteinases (MMP-2) expression on endothelial cells. Taken together, these findings demonstrate that lambda-CO is a potential angiogenesis inhibitor with combined effects of inhibiting invasion, migration, and proliferation.

Marine invertebrates harbour a wealth of micro-organisms in their bodies. Most of these micro-organisms can catabolize antibiotic compounds as chemical-defence compounds. These compounds not only play an important protective role for their producer and for their hosts, but also have high potential in medicinal applications. In order to discover natural anticancer products, 29 marine bacterial strains have been isolated from the sponge Hymeniacidon perleve, samples of which were collected from the intertidal zone during low tide off Nanji island in Eastern China. By means of a cytotoxicity bioassay, one strain, NJ6-3-1, with significant cytotoxic activity, was selected for culture in a 30-litre fermentation tank. The major cytotoxic compound in the metabolites of NJ6-3-1, separated by means of a bioassay-guided fractionation process, has been identified as norharman (a beta-carboline alkaloid) by electron-impact MS and NMR analyses. Norharman showed cytotoxicity towards both the HeLa cervical-cancer cell line and the BGC-823 stomach-cancer cell line, with an IC(50) of 5 microg/ml. Several methods were used to study the mechanism by which norharman is cytotoxic to HeLa cells. By means of an Acridine Orange/ethidium bromide dual-staining assay, condensation of chromatin was observed. A TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling) assay showed degradation of DNA. Flow-cytometric analysis indicated that norharman could arrest cells at the G(2)/M phase of the cell cycle. These results demonstrate the cytotoxic mechanism of norharman involves the induction of apoptosis in HeLa cells.

Background Agaro-oligosaccharides derived from red seaweed polysaccharide have been reported to possess antioxidant activity. In order to assess the live protective effects of agar-oligosaccharides, we did both in vitro and in vivo studies based on own-made agaro-oligosaccharides, and the structural information of this oligosaccharide was also determined. Method Structure of agaro-oligosaccharides prepared with acid hydrolysis on agar was confirmed by matrix-assisted ultraviolet laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) and NMR. The antioxidant effect of agaro-oligosaccharides on intracellular reactive oxygen species (ROS) was assessed by 2', 7'-dichlorofluorescin diacetate. Carbon tetrachloride was used to induce liver injury, some index including SOD, GSH-Px, MDA, AST, ALT were examined to determine the hepatoprotective effect of agaro-oligosaccharides. Results Agaro-oligosaccharides we got were composed of odd polymerizations with molecular weights ranged from 500 to 2500. Results from intracellular test indicated that agaro-oligosaccharides could significantly scavenge the level of oxidants in the hepatocytes, more beneficially, also associated with the improvement of cell viability In vivo studies of the antioxidant effects on tissue peroxidative damage induced by carbon tetrachloride in rat model indicated that agaro-oligosaccharides could elevate the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and decrease the level of malondialdehyde (MDA), glutamate oxaloacetate transaminase (AST), glutamic pyruvic transaminase (ALT) significantly. At 400 mg/kg, MDA level reduced 44 % and 21 % in liver and heart, SOD and GSH-Px increased to highest in liver and serum, while ALT level decreased 22.16 % in serum. Conclusion Overall, the results of the present study indicate that agaro-oligosaccharides can exert their in vitro and in vivo hepatoprotective effect through scavenging oxidative damage induced by ROS.

Background Carrageenan is a traditional ingredient that has been widely used in the food industry. In the present study, we propose a hypothesis that carrageenan is a conditional inflammatory agent. When the intestinal tract is in an “unhealthy” state such as that during bacterial infection or acute inflammation, carrageenan can synergistically enhance the inflammatory response. Methods BALB/C mice received κ-carrageenan via intragastric administration prior to the induction of oxazolone colitis. Weight changes, survival rate, histologic change, secretion of inflammatory cytokines, ratio of regulatory T cells (Tregs) in peripheral blood, and expression of genes and proteins involved in inflammation and cell proliferation in the colonic mucosa were examined. Results Intragastric administration of κ-carrageenan to BALB/c mice prior to the induction of oxazolone colitis resulted in an aggravation of body weight loss, a decrease in the survival ratio, aggravation of colonic inflammation, and decrease in the ratio of CD4 + CD25+/CD4+. The secretion of interleukin-4 (IL-4), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) also significantly increased after κ-carrageenan administration. κ-Carrageenan, together with oxazolone, suppressed the expression of forkhead box p3 (FOXp3) and increased the expression of Toll-like receptor 4 (TLR4), Nuclear factor-κB (NF-κB), and proliferating cell nuclear antigen in the colonic mucosa. These results were confirmed by qRT-PCR and western blot analyses at the molecular and protein levels, respectively. Conclusions κ-Carrageenan aggravated oxazolone-induced intestinal inflammation in BALB/c mice. This effect is associated with an activation of the TLR4-NF-κB pathway, a decreased ratio of Tregs, and the induction of Th2-dependent immune responses.