Functional Association between Storage Protein Mobilization and Redox Signaling in Narrow-Leafed Lupin (Lupinus angustifolius L.) Seed Germination and Seedling Development

(1) Background: Seed storage mobilization, together with oxidative metabolism, with the ascorbate-glutathione (AsA-GSH) cycle as a crucial signaling and metabolic functional crossroad, is one of the main regulators of the control of cell morphogenesis and division, a fundamental physiological process driving seed germination and seedling growth. This study aims to characterize the cellular changes, composition, and patterns of the protein mobilization and ROS-dependent gene expression of redox metabolism in Lupinus angustifolius L. (narrow-leafed lupin, NLL) cotyledons during seed germination. (2) Methods: We performed gene expression analyses via RT-qPCR for conglutins α (1, 2, and 3), β (1, 2, and 5), γ (1, 2), and δ (2 and 4), including a ubiquitin gene as a control, and for redox metabolism-related genes; GADPH was used as a control gene. A microscopic study was developed on cotyledon samples from different germination stages, including as IMB (imbibition), and 2-5, 7, 9, and 11 DAI (days after imbibition), which were processed for light microscopy. SDS-PAGE and immunocytochemistry assays were performed using an anti-β-conglutin antibody (Agrisera), and an anti-rabbit IgG Daylight 488-conjugated secondary antibody. The controls were made while omitting primary Ab. (3) Results and Discussion: Our results showed that a large amount of seed storage protein (SSP) accumulates in protein bodies (PBs) and mobilizes during germination. Families of conglutins (β and γ) may play important roles as functional and signaling molecules, beyond the storage function, at intermediate steps of the seed germination process. In this regard, metabolic activities are closely associated with the regulation of oxidative homeostasis through AsA-GSH activities (γ-L-Glutamyl-L-cysteine synthetase, NOS, Catalase, Cu/Zn-SOD, GPx, GR, GS, GsT) after the imbibition of NLL mature seeds, metabolism activation, and dormancy breakage, which are key molecular and regulatory signaling pathways with particular importance in morphogenesis and developmental processes. (4) Conclusions: The knowledge generated in this study provides evidence for the functional changes and cellular tightly regulated events occurring in the NLL seed cotyledon, orchestrated by the oxidative-related metabolic machinery involved in seed germination advancement.

Transcriptomic Insight into the Pollen Tube Growth of Olea europaea L. subsp. europaea Reveals Reprogramming and Pollen-Specific Genes Including New Transcription Factors

The pollen tube is a key innovation of land plants that is essential for successful fertilisation. Its development and growth have been profusely studied in model organisms, but in spite of the economic impact of olive trees, little is known regarding the genome-wide events underlying pollen hydration and growth in this species. To fill this gap, triplicate mRNA samples at 0, 1, 3, and 6 h of in vitro germination of olive cultivar Picual pollen were analysed by RNA-seq. A bioinformatics R workflow called RSeqFlow was developed contemplating the best practices described in the literature, covering from expression data filtering to differential expression and clustering, to finally propose hub genes. The resulting olive pollen transcriptome consisted of 22,418 reliable transcripts, where 5364 were differentially expressed, out of which 173 have no orthologue in plants and up to 3 of them might be pollen-specific transcription factors. Functional enrichment revealed a deep transcriptional reprogramming in mature olive pollen that is also dependent on protein stability and turnover to allow pollen tube emergence, with many hub genes related to heat shock proteins and F-box-containing proteins. Reprogramming extends to the first 3 h of growth, including processes consistent with studies performed in other plant species, such as global down-regulation of biosynthetic processes, vesicle/organelle trafficking and cytoskeleton remodelling. In the last stages, growth should be maintained from persistent transcripts. Mature pollen is equipped with transcripts to successfully cope with adverse environments, even though the in vitro growth seems to induce several stress responses. Finally, pollen-specific transcription factors were proposed as probable drivers of pollen germination in olive trees, which also shows an overall increased number of pollen-specific gene isoforms relative to other plants.

β-Conglutins' Unique Mobile Arm Is a Key Structural Domain Involved in Molecular Nutraceutical Properties of Narrow-Leafed Lupin (Lupinus angustifolius L.)

Narrow-leafed lupin (NLL; Lupinus angustifolius L.) has multiple nutraceutical properties that may result from unique structural features of β-conglutin proteins, such as the mobile arm at the N-terminal, a structural domain rich in α-helices. A similar domain has not been found in other vicilin proteins of legume species. We used affinity chromatography to purify recombinant complete and truncated (without the mobile arm domain, tβ5 and tβ7) forms of NLL β5 and β7 conglutin proteins. We then used biochemical and molecular biology techniques in ex vivo and in vitro systems to evaluate their anti-inflammatory activity and antioxidant capacity. The complete β5 and β7 conglutin proteins decreased pro-inflammatory mediator levels (e.g., nitric oxide), mRNA expression levels (iNOS, TNFα, IL-1β), and the protein levels of pro-inflammatory cytokine TNF-α, interleukins (IL-1β, IL-2, IL-6, IL-8, IL-12, IL-17, IL-27), and other mediators (INFγ, MOP, S-TNF-R1/-R2, and TWEAK), and exerted a regulatory oxidative balance effect in cells as demonstrated in glutathione, catalase, and superoxide dismutase assays. The truncated tβ5 and tβ7 conglutin proteins did not have these molecular effects. These results suggest that β5 and β7 conglutins have potential as functional food components due to their anti-inflammatory and oxidative cell state regulatory properties, and that the mobile arm of NLL β-conglutin proteins is a key domain in the development of nutraceutical properties, making NLL β5 and β7 excellent innovative candidates as functional foods.

OliveAtlas: A Gene Expression Atlas Tool for Olea europaea

The olive (Olea europaea L.) is an ancient crop of great importance in the Mediterranean basin due to the production of olive oil and table olives, which are important sources of fat and have benefits for human health. This crop is expanding and increasing its production worldwide and five olive genomes have recently been sequenced, representing a wild olive and important cultivars in terms of olive oil production, intensive agriculture, and adaptation to the East Asian climate. However, few bioinformatic and genomic resources are available to assist olive research and breeding, and there are no platforms to query olive gene expression data. Here, we present OliveAtlas, an interactive gene expression atlas for olive with multiple bioinformatics tools and visualization methods, enabling multiple gene comparison, replicate inspection, gene set enrichment, and data downloading. It contains 70 RNA-seq experiments, organized in 10 data sets representing the main olive plant organs, the pollen germination and pollen tube elongation process, and the response to a collection of biotic and abiotic stresses, among other experimental conditions. OliveAtlas is a web tool based on easyGDB with expression data based on the 'Picual' genome reference and gene annotation.

A comprehensive dataset of the extra virgin olive oil (EVOO) proteome

Proteins and peptides are minor components of vegetal oils. The presence of these compounds in virgin olive oil was first reported in 2001, but the nature of the olive oil proteome is still a puzzling question for food science researchers. In this paper, we have compiled for a first time a comprehensive proteomic dataset of olive fruit and fungal proteins that are present at low but measurable concentrations in a vegetable oil from a crop of great agronomical relevance as olive (Olea europaea L.). Accurate mass nLC-MS data were collected in high definition direct data analysis (HD-DDA) mode using the ion mobility separation step. Protein identification was performed using the Mascot Server v2.2.07 software (Matrix Science) against an ad hoc database made of olive protein entries. Starting from this proteomic record, the impact of these proteins on olive oil stability and quality could be tested. Moreover, the effect of olive oil proteins on human health and their potential use as functional food components could be also evaluated. In addition, this dataset provides a resource for use in further functional comparisons across other vegetable oils, and also expands the proteomic resources to non-model species, thus also allowing further comparative inter-species studies. The data presented here are related to the research article of Castro et al. [1].

Identification of seed storage proteins as the major constituents of the extra virgin olive oil proteome

Proteins are minor components of extra virgin olive oil (EVOO), but the nature of the olive oil proteome is still elusive. In this paper, we have uncovered the EVOO proteome for the first time. Seed storage proteins of globulin-type were identified as the most abundant proteins in EVOO, which also contains an active 13-lipoxygenase and several potential allergenic proteins, including the "panallergen" profilin. We validated our proteomic data by Western blotting and enzyme activity assays. Our data also demonstrated that the seed is the main source of proteins in EVOO, while the contribution of the pulp is uncertain and needs further verification. The impact of EVOO proteins on its stability and quality, and on human health is discussed.

Lipid Composition and Associated Gene Expression Patterns during Pollen Germination and Pollen Tube Growth in Olive (Olea europaea L.)

Pollen lipids are essential for sexual reproduction, but our current knowledge regarding lipid dynamics in growing pollen tubes is still very scarce. Here, we report unique lipid composition and associated gene expression patterns during olive pollen germination. Up to 376 genes involved in the biosynthesis of all lipid classes, except suberin, cutin and lipopolysaccharides, are expressed in olive pollen. The fatty acid profile of olive pollen is markedly different compared with other plant organs. Triacylglycerol (TAG), containing mostly C12-C16 saturated fatty acids, constitutes the bulk of olive pollen lipids. These compounds are partially mobilized, and the released fatty acids enter the β-oxidation pathway to yield acetyl-CoA, which is converted into sugars through the glyoxylate cycle during the course of pollen germination. Our data suggest that fatty acids are synthesized de novo and incorporated into glycerolipids by the 'eukaryotic pathway' in elongating pollen tubes. Phosphatidic acid is synthesized de novo in the endomembrane system during pollen germination and seems to have a central role in pollen tube lipid metabolism. The coordinated action of fatty acid desaturases FAD2-3 and FAD3B might explain the increase in linoleic and alpha-linolenic acids observed in germinating pollen. Continuous synthesis of TAG by the action of diacylglycerol acyltransferase 1 (DGAT1) enzyme, but not phosphoplipid:diacylglycerol acyltransferase (PDAT), also seems plausible. All these data allow for a better understanding of lipid metabolism during the olive reproductive process, which can impact, in the future, on the increase in olive fruit yield and, therefore, olive oil production.

Pigment epithelium-derived factor (PEDF) and PEDF-receptor in the adult mouse brain: Differential spatial/temporal localization pattern

Pigment epithelium-derived factor (PEDF) is a multifunctional protein which was initially described in the retina, although it is also present in other tissues. It functions as an antioxidant agent promoting neuronal survival. Recently, a PEDF receptor has shown an elevated binding affinity for PEDF. There are no relevant data regarding the distribution of both proteins in the brain, therefore the main goal of this work was to investigate the spatiotemporal presence of PEDF and PEDFR in the adult mouse brain, and to determine the PEDF blood level in mouse and human. The localization of both proteins was analyzed by different experimental methods such as immunohistochemistry, western-blotting, and also by enzyme-linked immunosorbent assay. Differential expression was found in some telencephalic structures and positive signals for both proteins were detected in the cerebellum. The magnitude of the PEDFR labeling pattern was higher than PEDF and included some cortical and subventricular areas. Age-dependent changes in intensity of both protein immunoreactions were found in the cortical and hippocampal areas with greater reactivity between 4 and 8 months of age, whilst others, like the subventricular zones, these differences were more evident for PEDFR. Although ubiquitous presence was not found in the brain for these two proteins, their relevant functions must not be underestimated. It has been described that PEDF plays an important role in neuroprotection and data provided in the present work represents the first extensive study to understand the relevance of these two proteins in specific brain areas.

Narrow-Leafed Lupin Main Allergen β-Conglutin (Lup an 1) Detection and Quantification Assessment in Natural and Processed Foods

The increasing prevalence of lupin allergy as a consequence to the functional characteristics of a growing number of sweet lupin-derived foods consumption makes the imperious necessity to develop analytical tools for the detection of allergen proteins in foodstuffs. The current study developed a new highly specific, sensitive and accurate ELISA method to detect, identify and quantify the lupin main allergen β-conglutin (Lup an 1) protein in natural and processed food. The implementation of accurate standards made with recombinant conglutin β1, and an anti-Lup an 1 antibody made from a synthetic peptide commonly shared among β-conglutin isoforms from sweet lupin species was able to detect up to 8.1250 ± 0.1701 ng (0.0406 ± 0.0009 ppm) of Lup an 1. This identified even lupin traces present in food samples which might elicit allergic reactions in sensitized consumers, such as β-conglutin proteins detection and quantification in processed (roasted, fermented, boiled, cooked, pickled, toasted, pasteurized) food, while avoiding cross-reactivity (false positive) with other legumes as peanut, chickpea, lentils, faba bean, and cereals. This study demonstrated that this new ELISA method constitutes a highly sensitive and reliable molecular tool able to detect, identify and quantify Lup an 1. This contributes to a more efficient management of allergens by the food industry, the regulatory agencies and clinicians, thus helping to keep the health safety of the consumers.

Effects of Virgin Olive Oils Differing in Their Bioactive Compound Contents on Metabolic Syndrome and Endothelial Functional Risk Biomarkers in Healthy Adults: A Randomized Double-Blind Controlled Trial

The aim of this study was to evaluate the effect of virgin olive oils (VOOs) enriched with phenolic compounds and triterpenes on metabolic syndrome and endothelial function biomarkers in healthy adults. The trial was a three-week randomized, crossover, controlled, double-blind, intervention study involving 58 subjects supplemented with a daily dose (30 mL) of three oils: (1) a VOO (124 ppm of phenolic compounds and 86 ppm of triterpenes); (2) an optimized VOO (OVOO) (490 ppm of phenolic compounds and 86 ppm of triterpenes); and (3) a functional olive oil (FOO) high in phenolic compounds (487 ppm) and enriched with triterpenes (389 ppm). Metabolic syndrome and endothelial function biomarkers were determined in vivo and ex vivo. Plasma high density lipoprotein cholesterol (HDLc) increased after the OVOO intake. Plasma endothelin-1 levels decreased after the intake of the three olive oils, and in blood cell cultures challenged. Daily intake of VOO enriched in phenolic compounds improved plasma HDLc, although no differences were found at the end of the three interventions, while VOO with at least 124 ppm of phenolic compounds, regardless of the triterpenes content improved the systemic endothelin-1 levels in vivo and ex vivo. No effect of triterpenes was observed after three weeks of interventions. Results need to be confirmed in subjects with metabolic syndrome and impaired endothelial function (Clinical Trials number NCT02520739).

Narrow-leafed lupin (Lupinus angustifoliusL.) seed β-conglutins reverse the induced insulin resistance in pancreatic cells

Narrow-leafed lupin β-conglutin proteins may help to prevent and treat insulin resistance through pleiotropic effects.

S-nitroso- and nitro- proteomes in the olive (Olea europaea L.) pollen. Predictive versus experimental data by nano-LC-MS

The data presented here are related to the research article entitled "Generation of nitric oxide by olive (Olea europaea L.) pollen during in vitro germination and assessment of the S-nitroso- and nitro-proteomes by computational predictive methods" doi:10.1016/j.niox.2017.06.005 (Jimenez-Quesada et al., 2017) [1]. Predicted cysteine S-nitrosylation and Tyr-nitration sites in proteins derived from a de novo assembled and annotated pollen transcriptome from olive tree (Olea europaea L.) were obtained after using well-established predictive tools in silico. Predictions were performed using both default and highly restrictive thresholds. Numerous gene products identified with these characteristics are listed here. An experimental validation of the data, consisting in nano-LC-MS (Liquid Chromatography-Mass Spectrometry) determination of olive pollen proteins after immunoprecipitation with antibodies to anti-S-nitrosoCys and anti-3-NT (NitroTyrosine) allowed identification of numerous proteins subjected to these two post-translational modifications, which are listed here together with information regarding their cross-presence among the predictions.

Generation of nitric oxide by olive (Olea europaea L.) pollen during in vitro germination and assessment of the S-nitroso- and nitro-proteomes by computational predictive methods

Nitric oxide is recognized as a signaling molecule involved in a broad range of physiological processes in plants including sexual reproduction. NO has been detected in the pollen grain at high levels and regulates pollen tube growth. Previous studies demonstrated that NO as well as ROS are produced in the olive reproductive tissues in a stage- and tissue-specific manner. The aim of this study was to assess the production of NO throughout the germination of olive (Olea europaea L.) pollen in vitro. The NO fluorescent probe DAF-2DA was used to image NO production in situ, which was correlated to pollen viability. Moreover, by means of a fluorimetric assay we showed that growing pollen tubes release NO. GSNO -a mobile reservoir of NO, formed by the S-nitrosylation of NO with reduced glutathione (GSH) - was for the first time detected and quantified at different stages of pollen tube growth using a LC-ES/MS analysis. Exogenous NO donors inhibited both pollen germination and pollen tube growth and these effects were partially reverted by the specific NO-scavenger c-PTIO. However, little is known about how NO affects the germination process. With the aim of elucidating the putative relevance of protein S-nitrosylation and Tyr-nitration as important post-translational modifications in the development and physiology of the olive pollen, a de novo assembled and annotated reproductive transcriptome from olive was challenged in silico for the putative capability of transcripts to become potentially modified by S-nitrosylation/Tyr-nitration according to well-established criteria. Numerous gene products with these characteristics were identified, and a broad discussion as regards to their potential role in plant reproduction was built after their functional classification. Moreover, the importance of both S-nitrosylation/Tyr-nitrations was experimentally assessed and validated by using Western blotting, immunoprecipitation and proteomic approaches.

Narrow Leafed Lupin Beta-Conglutin Proteins Epitopes Identification and Molecular Features Analysis Involved in Cross-Allergenicity to Peanut and Other Legumes

The use of narrow leafed lupin - NLL (Lupinus angustifolius L.) as a new food is resulting in an increasing number of allergic reactions cases, particularly in atopic patients with other pre-existing legume allergies. In the current study, we have performed an extensive in silico analysis of the NLL seed β-conglutin proteins, a new family of major allergen proteins identified in NLL, and a comparison to other relevant food allergens such as peanut Ara h 1. We analysed the variability of surface residues involved in conformational IgE-binding epitopes, lineal B- and T-cell epitopes, and changes in 2-D structural elements and 3D motives, with the aim to investigate cross-allergenicity among lupin, peanut, and other different legumes. Our results revealed that considerable structural differences exist, particularly affecting 2-D elements (loops and coils), and numerous micro-heterogeneities are present in fundamental residues directly involved in epitopes differential variability. Thus, variability of residues involved in IgE-binding epitopes might be a major contributor to the observed differences in cross-allergenicity among legumes.

Ole e 13 is the unique food allergen in olive: Structure-functional, substrates docking, and molecular allergenicity comparative analysis

Thaumatin-like proteins (TLPs) are enzymes with important functions in pathogens defense and in the response to biotic and abiotic stresses. Last identified olive allergen (Ole e 13) is a TLP, which may also importantly contribute to food allergy and cross-allergenicity to pollen allergen proteins. The goals of this study are the characterization of the structural-functionality of Ole e 13 with a focus in its catalytic mechanism, and its molecular allergenicity by extensive analysis using different molecular computer-aided approaches covering a) functional-regulatory motifs, b) comparative study of linear sequence, 2-D and 3D structural homology modeling, c) molecular docking with two different β-D-glucans, d) conservational and evolutionary analysis, e) catalytic mechanism modeling, and f) IgE-binding, B- and T-cell epitopes identification and comparison to other allergenic TLPs. Sequence comparison, structure-based features, and phylogenetic analysis identified Ole e 13 as a thaumatin-like protein. 3D structural characterization revealed a conserved overall folding among plants TLPs, with mayor differences in the acidic (catalytic) cleft. Molecular docking analysis using two β-(1,3)-glucans allowed to identify fundamental residues involved in the endo-1,3-β-glucanase activity, and defining E84 as one of the conserved residues of the TLPs responsible of the nucleophilic attack to initiate the enzymatic reaction and D107 as proton donor, thus proposing a catalytic mechanism for Ole e 13. Identification of IgE-binding, B- and T-cell epitopes may help designing strategies to improve diagnosis and immunotherapy to food allergy and cross-allergenic pollen TLPs.

Hypoxia-inducible factor-1 modulates the expression of vascular endothelial growth factor and endothelial nitric oxide synthase induced by eccentric exercise

The present study investigated the effects of acute and chronic eccentric exercise on the hypoxia-inducible factor (HIF)-1α activation response and the concomitant modulation of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expression in rat skeletal muscle. Twenty-four male Wistar rats were randomly assigned to three experimental groups: rested control group, acutely exercised group after an intermittent downhill protocol for 90 min, and acutely exercise group with a previous eccentric training of 8 wk. HIF-1α activation, VEGF and eNOS gene expression, protein content, and promoter activation were assessed in vastus lateralis muscle biopsies. Acute eccentric exercise induced a marked activation of HIF-1α and resulted in increased VEGF and eNOS mRNA level and protein concentration. The binding of HIF-1α to the VEGF and eNOS promoters, measured by a chromatin immunoprecipitation assay, was undetectable in rested rats, whereas it was evident in acutely exercised animals. Acute exercise also increased myeloperoxidase, toll-like receptor-4, tumor necrosis factor-α, and interleukin-1β protein content, suggesting a contribution of proinflammatory stimuli to HIF-1α activation and VEGF overexpression. All of these effects were partially abolished by training. Moreover, training resulted in an increased capillary density. In summary, our findings indicate that eccentric exercise prompts an HIF-1α response in untrained skeletal muscle that contributes to the upregulation of VEGF and eNOS gene expression and is attenuated after an eccentric training program.

A review of the melatonin functions in zebrafish physiology

Melatonin is part of the evolutionary conserved highly functional network in vertebrates. It plays a central role in the adaptative behavior of the animal to the environment, including entrainment of daily and annual physiological rhythms, reproductive behavior, food intake, locomotor activity, growth, and breeding performance. In zebrafish, apart from its synchronizing capabilities, melatonin seems to have a major role in multiple physiological processes. Extensive knowledge of its genome and the identification of a series of genes with the same functions as those in humans, the relative ease of obtaining mutants, and the similarities between zebrafish and human pathologies make it an excellent experimental model organism of human diseases. Moreover, it is a common experimental species because of easy handling, breeding, and developmental control. Among other pathophysiologies, zebrafish are now used in studies of neurodegeneration and neurological diseases, endocrine diseases, behavior, muscular dystrophies, developmental alterations, circadian rhythms, and drugs screening. The purpose of this review was to update the current knowledge on the synthesis and biological functions of melatonin in zebrafish, keeping in mind its relevance not only in the physiology of the animal, but also in pathophysiological conditions.

Liver X receptor α-mediated regulation of lipogenesis by core and NS5A proteins contributes to HCV-induced liver steatosis and HCV replication

Molecular mechanisms contributing to hepatitis C virus (HCV)-associated steatosis are not well established, although HCV gene expression has been shown to alter host cell cholesterol/lipid metabolism. As liver X receptors (LXRs) play a role as key modulators of metabolism signaling in the development of steatosis, we aimed to investigate in an HCV in vitro model the effect of HCV NS5A protein, core protein, and viral replication on the intracellular lipid accumulation and the LXRα-regulated expression of lipogenic genes. The effects of LXRα siRNA or agonist GW3965 treatment on lipogenesis and HCV replication capacity in our HCV replicon system were also examined. NS5A- and core-expressing cells and replicon-containing cells exhibited an increase of lipid accumulation by inducing the gene expression and the transcriptional activity of LXRα, and leading to an increased expression of its lipogenic target genes sterol regulatory element binding protein-1c, peroxisome proliferator-activated receptor-γ, and fatty acid synthase. Transcriptional induction by NS5A protein, core protein, and viral replication occurred via LXR response element activation in the lipogenic gene promoter. No physical association between HCV proteins and LXRα was observed, whereas NS5A and core proteins indirectly upregulated LXRα through the phosphatidylinositol 3-kinase pathway. Finally, it was found that LXRα knockdown or agonist-mediated LXRα induction directly regulated HCV-induced lipogenesis and HCV replication efficiency in replicon-containing cells. Combined, our data suggest that LXRα-mediated regulation of lipogenesis by core and NS5A proteins may contribute to HCV-induced liver steatosis and to the efficient replication of HCV.

Hepatic fatty acid translocase CD36 upregulation is associated with insulin resistance, hyperinsulinaemia and increased steatosis in non-alcoholic steatohepatitis and chronic hepatitis C

BACKGROUND

Fatty acid translocase CD36 (FAT/CD36) mediates uptake and intracellular transport of long-chain fatty acids in diverse cell types. While the pathogenic role of FAT/CD36 in hepatic steatosis in rodents is well-defined, little is known about its significance in human liver diseases.

OBJECTIVE

To examine the expression of FAT/CD36 and its cellular and subcellular distribution within the liver of patients with non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis C virus (HCV) infection.

PATIENTS

34 patients with non-alcoholic steatosis (NAS), 30 with non-alcoholic steatohepatitis (NASH), 66 with HCV genotype 1 (HCV G1) and 32 with non-diseased liver (NL).

METHODS

Real-time PCR and western blot analysis were used to assess hepatic FAT/CD36 expression. Computational image analysis of immunostained liver biopsy sections was performed to determine subcellular distribution and FAT/CD36 expression index.

RESULTS

Compared with NL, hepatic mRNA and protein levels of FAT/CD36 were significantly higher in patients with NAS (median fold increase 0.84 (range 0.15-1.61) and 0.66 (range 0.33-1.06), respectively); NASH (0.91 (0.22-1.81) and 0.81 (0.38-0.92), respectively); HCV G1 without steatosis (0.30 (0.17-1.59) and 0.33 (0.29-0.52), respectively); and HCV G1 with steatosis (0.85 (0.15-1.98) and 0.87 (0.52-1.26), respectively). In contrast to NL, FAT/CD36 was predominantly located at the plasma membrane of hepatocytes in patients with NAFLD and HCV G1 with steatosis. A significant correlation was observed between hepatic FAT/CD36 expression index and plasma insulin levels, insulin resistance (HOMA-IR) and histological grade of steatosis in patients with NASH (r=0.663, r=0.735 and r=0.711, respectively) and those with HCV G1 with steatosis (r=0.723, r=0.769 and r=0.648, respectively).

CONCLUSIONS

Hepatic FAT/CD36 upregulation is significantly associated with insulin resistance, hyperinsulinaemia and increased steatosis in patients with NASH and HCV G1 with fatty liver. Translocation of this fatty acid transporter to the plasma membrane of hepatocytes may contribute to liver fat accumulation in patients with NAFLD and HCV.

Eccentric exercise induces nitric oxide synthase expression through nuclear factor-κB modulation in rat skeletal muscle

This study aimed to investigate the effect of eccentric exercise on the expression of the different nitric oxide synthase (NOS) isoforms in rat deep vastus lateralis muscle. Twenty-four rats were allocated to four experimental groups: rested control group, acutely exercised group after an intermittent downhill protocol for 90 min, acutely exercised group treated with pyrrolidine dithiocarbamate (100 mg/kg ip) for 24 and 1 h before the acute exercise bout, and acutely exercised group with a previous submaximal eccentric training of 8 wk. Acutely exercised rats showed increased levels of protein tyrosine nitration, NF-κB binding, and phospho-IκBα content. A significant increase was observed in mRNA level and protein content of neuronal NOS, inducible NOS, and endothelial NOS. The binding of NF-κB to the NOS isoform promoters, measured by a chromatin immunoprecipitation assay, was undetectable in rested rats, whereas it was evident in acutely exercised animals. All of these effects were partially abolished by pyrrolidine dithiocarbamate treatment and by training. In summary, our findings provide a direct link between the NF-κB signaling cascade and NOS expression in skeletal muscle following eccentric exercise and suggest a modulation of the expression of the three NOS isoforms by this transcription factor.