Cloning and characterization of Lxr and Srebp1, and their potential roles in regulation of LC-PUFA biosynthesis in rabbitfish Siganus canaliculatus

Rabbitfish Siganus canaliculatus was the first marine teleost demonstrated to have the ability to biosynthesize C20-22 long-chain polyunsaturated fatty acids (LC-PUFA) from C18 PUFA precursors, which is generally absent or low in marine teleosts. Thus, understanding the molecular basis of LC-PUFA biosynthesis in rabbitfish will contribute to efforts aimed at optimizing LC-PUFA biosynthesis in teleosts, especially marine species. In the present study, the importance of the transcription factors liver X receptor (Lxr) and sterol regulatory element-binding protein 1 (Srebp1) in regulation of LC-PUFA biosynthesis in rabbitfish was investigated. First, full-length cDNAs of Lxr and Srebp1 were cloned and characterized. The Lxr mRNA displayed a ubiquitous tissue expression pattern while Srebp1 was highly expressed in eyes, brain and intestine. In rabbitfish primary hepatocytes treated with Lxr agonist T0901317, the expression of Lxr and Srebp1 was activated, accompanied by elevated mRNA levels of Δ4 and Δ6/Δ5 fatty acyl desaturases (Fad), key enzymes of LC-PUFA biosynthesis, as well as peroxisome proliferator-activated receptor γ (Pparγ). In addition, Srebp1 displayed higher expression levels in liver of rabbitfish fed a vegetable oil diet or reared at 10 ppt salinity, which were conditions reported to increase the liver expression of Δ4 and Δ6/Δ5 Fad and LC-PUFA biosynthetic ability, than fish fed a fish oil diet or reared at 32 ppt, respectively. These results suggested that Lxr and Srebp1 are involved in regulation of LC-PUFA biosynthesis probably by promoting the expression of two Fads in rabbitfish liver, which, to our knowledge, is the first report in marine teleosts

Effect of intra-abdominal infection on immunological function and HMGB1/TLR4/NF-κB signaling pathway in patients with severe acute pancreatitis

The aim of this article is to investigate the effects of intra-abdominal infection on immunological function and high-mobility group box 1 protein (HMGB1)/toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway in patients with severe acute pancreatitis (SAP). Clinical data of SAP patients were retrospectively analyzed. SAP patients were divided into intra-abdominal infection group (103 SAP patients) and control group (115 SAP patients without intra-abdominal infection). All patients were evaluated with the Acute Physiology and Chronic Health Evaluation (APACHE) II score. Enzyme-linked immunosorbent assay (ELISA) assays were used to detect the levels of serum endotoxin, d -lactate, diamine oxidase, IgG, IgM, IgA, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and HMGB1. Western blotting was performed to detect the levels of TLR4 and NF-κB in peripheral blood lymphocytes. Compared with control group, the APACHE II score (12.60 ± 3.81 vs 9.55 ± 3.02) and serum endotoxin (0.33 ± 0.15 vs 0.19 ± 0.09 EU/mL), d -lactate (4.33 ± 0.16 vs 4.02 ± 0.12 mg/L), and diamine oxidase (3.88 ± 0.16 vs 3.65 ± 0.13 EU/mL) levels in intra-abdominal infection group were increased significantly (all P  < 0.001); serum IgG (7.33 ± 0.82 vs 9.05 ± 0.90 g/L), IgM (1.04 ± 0.49 vs 1.18 ± 0.53 g/L), and IgA (1.65 ± 0.79 vs 1.96 ± 0.88 g/L) levels in intra-abdominal infection group were decreased significantly, while serum IL-1β (118.55 ± 17.04 vs 83.61 ± 12.28 ng/L), IL-6 (12.05 ± 7.69 vs 9.89 ± 6.77 ng/L), TNF-α (25.61 ± 8.76 vs 19.20 ± 8.33 ng/L), and HMGB1 (48.91 ± 20.63 vs 32.74 ± 17.05 μg/L) levels were increased significantly (all P  < 0.05); TLR4 and NF-κB in intra-abdominal infection group were increased significantly (both P  < 0.001). The intra-abdominal infection can lead to intestinal barrier dysfunction, aggravated inflammatory response, and immune dysfunction in SAP patients, which may be related to the activation of HMGB1/TLR4/NF-κB pathway caused by intra-abdominal infection

A Study on Monitoring and Supervision of Ship Nitrogen-Oxide Emissions and Fuel-Sulfur-Content Compliance

Regulations for the control of air-pollutant emissions from ships within pollutant emission control areas (ECAs) have been issued for several years, but the lack of practical technologies and fundamental theory in the implementation process remains a challenge. In this study, we designed a model to calculate the nitrogen-oxide-emission intensity of ships and the sulfur content of ship fuels using theoretical deduction from the law of the conservation of mass. The reliability and availability of the derived results were empirically evaluated using measurement data for NOx, SO2, and CO2 in the exhaust gas of a demonstration ship in practice. By examining the model and the measured or registered fuel-oil-consumption rates of ships, a compliance-determination workflow for NOx-emission intensity and fuel-sulfur-content monitoring and supervision in on-voyage ships were proposed. The results showed that the ship fuel’s NOx-emission intensity and sulfur content can be evaluated by monitoring the exhaust-gas composition online and used to assist in maritime monitoring and the supervision of pollutant emissions from ships. It is recommended that uncertainties regarding sulfur content should be considered within 15% during monitoring and supervision. The established model and workflow can assist in maritime monitoring. Meanwhile, all related governments and industry-management departments are advised to actively lead the development of monitoring and supervision technology for ship-air-pollutant control in ECAs, as well as strengthening the quality management of ships’ static data

Involvement of oxidative stress and cytoskeletal disruption in microcystin-induced apoptosis in CIK cells

The outbreak of cyanobacterial blooms induces the production and release of microcystins (MCs) into water, representing a health hazard to aquatic organisms and even humans. Some recent studies have suggested that kidney is another important target organ of MCs except liver, however, the potential toxicity mechanisms are still unclear. In this study, we first investigated the collaborative effect of oxidative stress and cytoskeletal disruption in microcystin-induced apoptosis in CIK (Ctenopharyngodon idellus kidney) cells in vitro. CIK cells were treated with 0, 1, 10, and 100 mu g/L microcystin-LR (MC-LR) for 24 and 48 h. Cell viability was increased by MC-LR in 1 mu g/L group, while decreased in 100 mu g/L group at 48 h. Cell cycle assay showed that 1 and 10 mu g/L MC-LR induced cell cycle through G(1) into S and G(2)/M phases, while 100 mu g/L MC-LR reduced G2/M phase population. MC-LR markedly induced apoptosis in 10 and 100 mu g/L groups. Elevated reactive oxygen species (ROS) production, increased malondialdehyde (MDA) contents, decreased glutathione (GSH) levels, and modulated antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) were observed in CIK cells exposed to MC-LR. These alterations were more pronounced at higher doses (10 and 100 mu g/L), indicating that oxidative stress was induced by MC-LR. Laser scanning confocal microscope observation showed aggregation and collapse of microfilaments (MFs) and microtubules (MTs) in CIK cells, and even loss of some cytoskeleton structure. Moreover, transcriptional changes of cytoskeletal genes (beta-actin, Ic3a, and keratin) were also determined, which have a high probability with cytoskeleton structure damage. Our data suggest that oxidative stress and cytoskeletal disruption may interact with each other and jointly lead to apoptosis and renal toxicity induced by MCs. (C) 2015 Elsevier B.V. All rights reserved

Simulated Microgravity Reduces Focal Adhesions and Alters Cytoskeleton and Nuclear Positioning Leading to Enhanced Apoptosis via Suppressing FAK/RhoA-Mediated mTORC1/NF-κB and ERK1/2 Pathways

Simulated-microgravity (SMG) promotes cell-apoptosis. We demonstrated that SMG inhibited cell proliferation/metastasis via FAK/RhoA-regulated mTORC1 pathway. Since mTORC1, NF-&kappa;B, and ERK1/2 signaling are important in cell apoptosis, we examined whether SMG-enhanced apoptosis is regulated via these signals controlled by FAK/RhoA in BL6-10 melanoma cells under clinostat-modelled SMG-condition. We show that SMG promotes cell-apoptosis, alters cytoskeleton, reduces focal adhesions (FAs), and suppresses FAK/RhoA signaling. SMG down-regulates expression of mTORC1-related Raptor, pS6K, pEIF4E, pNF-&kappa;B, and pNF-&kappa;B-regulated Bcl2, and induces relocalization of pNF-&kappa;B from the nucleus to the cytoplasm. In addition, SMG also inhibits expression of nuclear envelope proteins (NEPs) lamin-A, emerin, sun1, and nesprin-3, which control nuclear positioning, and suppresses nuclear positioning-regulated pERK1/2 signaling. Moreover, rapamycin, the mTORC1 inhibitor, also enhances apoptosis in cells under 1 g condition via suppressing the mTORC1/NF-&kappa;B pathway. Furthermore, the FAK/RhoA activator, toxin cytotoxic necrotizing factor-1 (CNF1), reduces cell apoptosis, restores the cytoskeleton, FAs, NEPs, and nuclear positioning, and converts all of the above SMG-induced changes in molecular signaling in cells under SMG. Therefore, our data demonstrate that SMG reduces FAs and alters the cytoskeleton and nuclear positioning, leading to enhanced cell apoptosis via suppressing the FAK/RhoA-regulated mTORC1/NF-&kappa;B and ERK1/2 pathways. The FAK/RhoA regulatory network may, thus, become a new target for the development of novel therapeutics for humans under spaceflight conditions with stressed physiological challenges, and for other human diseases