Transcriptomic response of skeletal muscle to lipopolysaccharide in the gilthead seabream (Sparus aurata)
ABSTRACT: The physiological consequences of an activation of the immune system in fish are not well understood. In particular, skeletal muscle, due to its essential role in locomotion and whole-animal energy homeostasis, is a potentially important target of inflammation. In this study, we have evaluated the in vivo effects of lipopolysaccharide (LPS) on the white and red skeletal muscle transcriptome of the gilthead seabream (Sparus aurata) by microarray analysis at 24 and 72 hours after injection. In white muscle, the transcriptomic response was characterized by an up-regulation of genes involved in carbohydrate catabolism and protein synthesis at 24 hours and a complete reversal of this pattern at 72 hours. In red muscle, an up-regulation of genes involved in carbohydrate catabolism and protein synthesis was observed only at 72 hours after LPS administration. Interestingly, both white and red muscles showed a similar consistent down-regulation of immune genes at 72 hours post-injection. However, genes involved in muscle contraction showed a general up-regulation in response to LPS in both types of muscle. In summary, LPS administration causes muscle type-specific responses regarding the expression of genes involved in carbohydrate and protein metabolism and a common decreased expression of immune genes in skeletal muscle, concomitant with increased expression of genes for contractile elements. Our results evidence a robust and tissue-specific transcriptomic response of the skeletal muscle to an acute inflammatory challenge. Total RNA from pooled control (n = 5) and LPS-treated (n = 5) sea bream white and red muscle tissues was labeled with Cy3-dUTP and Cy5-dUTP (GE Healthcare, Barcelona, Spain). We used a dye swap experimental design and each cDNA from a pooled RNA sample was hybridized to two microarrays. For the first slide, test and control cDNA were labeled with Cy5 and Cy3 respectively, and for the second array dye assignment was reversed. Therefore, samples from individual fish within each group were pooled and expression values shown represent the means of 6 × 2 = 12 technical replicates. A total of eight slides were used in this study.
Project description:Training at sustainable swimming speeds can produce changes in fish skeletal muscle that are important for aquaculture due to their growth-potentiating effects. Such changes may be even more relevant when fish are fed diets containing an increasing proportion of carbohydrates as an energy source. We evaluated the effects of moderate-intensity sustained swimming on the transcriptomic response of red and white muscle in rainbow trout fed a carbohydrate-rich diet using microarray and qPCR. Analysis of the red and white muscle transcriptome revealed significant changes in the expression of a large number of genes (395 and 597, respectively), with a total of 218 differentially expressed genes (DEGs) common for both muscles. A large number of the genes involved in glucose use and energy generation, contraction, development, synthesis and catabolism of proteins were up-regulated in red and white muscle. Additionally, DEGs in both muscles were involved in processes of defense response and apoptosis. Skeletal muscle contraction activates a transcriptional program required for the successful adaptation of both muscles to the changing demands imposed by swimming conditions. Future studies should further clarify the mechanisms involved in the adaptation of both tissues to exercise and assess possible benefits of such conditions for cultured fish. Total RNA from pooled red and white skeletal muscle samples of individual rainbow trout from each group (resting fish, n=8; swimming fish, n=8) was labeled with Cy3-dUTP and Cy5-dUTP (GE Healthcare, Barcelona, Spain). We used a dye swap experimental design and each cDNA from a pooled RNA sample was hybridized to two microarrays. For the first slide, cDNAs from resting and swimming fish were labeled with Cy5 and Cy3, respectively, and for the second array dye assignment was reversed. Therefore, samples from individual fish within each group were pooled and expression values shown represent the means of 6 × 2 = 12 technical replicates. A total of four slides were used in this study
Project description:Metabolic processes and sexual maturation closely interact during the long-distance reproductive migration of many fish species to their spawning grounds. In the present study, we have for the first time used exercise experimentally to investigate the effects on sexual maturation in rainbow trout. Pubertal autumn-spawning seawater-raised female rainbow trout Oncorhynchus mykiss (n=26; 50-cm, 1.5-kg) were rested or swum at a near optimal speed of 0.75 body-lengths per second in a 6,000 L swim-flume under natural reproductive conditions (16 °C fresh-water, starvation, 8h-light:16h-dark photoperiod). Fish were sampled after arrival and subsequently after 10 days (resting or swimming 307 km) and 20 days (resting or swimming 636 km). Ovarian development was significantly reduced in the swimmers. Analysis of the expression of key factors in the reproductive axis included pituitary kiss1-receptor, lh and fsh and ovarian lh-receptor, fsh-receptor, aromatase and vitellogenin-receptor (vtgr). Swimmers had lower pituitary lh and ovarian vtgr expression than resters. Furthermore, the number of late vitellogenic oocytes was lower in swimmers than in resters, probably resulting from the lower vtgr expression, and vitellogenin plasma levels were higher. Therefore, swimming exercise suppresses oocyte development possibly by inhibiting vitellogenin uptake. Transcriptomic changes that occurred in the ovary of exercised fish were investigated using a salmonid cDNA microarray platform. Protein biosynthesis and energy provision were among the sixteen functional categories that were all down-regulated in the ovary. Down-regulation of the transcriptomic response in the ovary illustrates the priority of energy reallocation and will save energy to fuel exercise. A swimming-induced ovarian developmental suppression at the start of vitellogenesis during long-term reproductive migration may be a strategy to avoid precocious muscle atrophy. In order to simulate the natural reproductive conditions of anadromous salmonids, experiments were performed with sea water-raised rainbow trout, Oncorhynchus mykiss. Resters and swimmers were starved during the experiment, seawater was replaced by fresh water and photoperiod was changed. These changes were expected to affect reproductive parameters but as ‘background’ effect because both resters as swimmers were experiencing these conditions at the same time in the same set-up. Any additional effects in swimming fish would thus be caused by swimming only. Pubertal autumn spawning rainbow trout (n=26; ~50 cm, ~1.5 kg) were purchased from a Danish exporter (Frederiksvaerk Aleexport) where they had been raised for 2 years in freshwater followed by 4 months in sea water cages at 10 ‰. They were transferred by truck within 16 h to Spakenburg (Spakenburg Paling, The Netherlands) and subsequently in the same water in a similar holding tank to the swim-flume at Leiden University (The Netherlands). The next day, 5 randomly chosen fish were sampled as ‘start’-group while others were randomly divided into a ‘rest’-group (n=10) and a ‘swim’-group (n=11). During the following 4 days, the brackish 10 ‰ water was stepwise replaced by freshwater at 16 °C and photoperiod was changed from 16L:8D to 8L:16D. Fish were then acclimatized for two days to their new conditions. Subsequently, swimmers were first swum at a speed of 0.33 body-lengths per second (BL/s) which was increased the next day to the final, near optimal speed of 0.75 BL/s (0.34 m/s or 29.4 km/day). Fish were sampled after 10 days (5 resters and 5 swimmers) and 20 days (5 resters and 6 swimmers). At sampling, fish were anesthetized using oil of cloves that was commercially purchased from a drugstore (diluted 1:10 in ethanol and used at a dosage of 1.5 ml/l). Fish were euthanized by decapitation and dissected for the ovary which was flash frozen in liquid nitrogen. RNA was isolated from pituitary and ovary samples according to the TRIZOL reagent protocol by Invitrogen (Baro, Spain). Isolated RNA was DNAse treated using RQ1 DNAse Promega (Madison, USA) and reverse transcribed using Superscript IIITM (Baro, Spain) according to the manufacturer’s protocol. Microarray analyses were performed on ovarian tissue for 20-days-swimmers vs. 20-days-resters. A rainbow trout cDNA microarray platform was used that was previously validated and described by Koskinen et al., 2004ab, Krasnov et al., 2005, MacKenzie et al., 2006ab, 2008 and Djordjevic et al., 2009, and deposited in GEO under accession number GPL1212, the original cDNA microarray (SFA2.0 chip), and GPL6154; the updated 1.8 K platform. This platform compromises 1818 genes representing 366 functional categories. Total RNA was extracted from flash frozen samples from experimental fish of the 20-days-swim group (n=5) and 20-days-rest group (n=5) like described before. Total RNA corresponding to pooled samples from the swim or rest groups was labeled with Cye3 and Cye5-dCTP (GE Healthcare, Barcelona, Spain) using SuperScript III reverse transcriptase (Invitrogen, Baro, Spain) and oligo(dT) primer. In our experience, reverse labeling combined with multiple replication of spots provide robust normalization and high statistical power of analyses. cDNA was purified with MicroconYM30 (Millipore). The slides were pretreated with 1% BSA(fraction V), 20 × SSC, 10% SDS (30 min at 50°C) and washed with 2 × SSC (3 min) and 0.2 × SSC (3 min) and hybridized overnight in cocktail containing 50 × Denhardt's, 20 × SSC, 10% SDS, 10μg/μl polyadenylate and 10 μg/μl yeast tRNA. All chemicals were from Sigma-Aldrich. Scanning was performed with ScanArray 5000 and images were processed with QuantArray (GSI Luminomics). The measurements in spots were filtered by criteria I/B ≥ 3 and (I-B)/(SI + SB) ≥ 0.6, where I and B are the mean signal and background intensities and SI, SB are the standard deviations. After subtraction of mean background, LOWESS normalization was performed. To assess differential expression of genes, the normalized log intensity ratios (expression ratio) were analyzed with Student's t-test (P <0.05). Validation of the microarray was performed by Q-PCR of 6 differentially expressed genes (DEGs) as described above. The used primers were either published (Alpha-globin I-1: Donate Jimeno, 2008) or designed, again by using the Genamics software.
Project description:We evaluated both the transcriptomic and inflammatory response in trout (O. mykiss) macrophages in primary cell culture stimulated with DAP-PGN (DAP; meso-diaminopimelic acid, PGN; peptidoglycan) from two strains of Escherichia coli (PGN-K12 and PGN-O111:B4) over time. Transcript profiling was assessed using function-targeted cDNA microarrays hibridation (n = 36) to differential responses to both PGNs that are both time and treatment dependen over trout macrophages. Wild type E. coli (K12) generated an increase in transcript number/diversity over time whereas PGN-O111:B4 stimulation resulted in a more specific and intense response. In line with this gene Ontology analysis (GO) highlights a specific transcriptomic remodelling for PGN-O111:B4 whereas results obtained for PGN-K12 shows a high similarity with a general LPS response where multiple functional classes are related to ribosome biogenesis or cellular metabolism Two-condition experiment, PGN vs. control cells. Biological replicates: 18 control, 18 treated. Dye-swap.
Project description:The focus of this study was to investigate the response of cultured rainbow trout erythrocytes to lipopolysaccharide (LPS) and to the analog viral dsRNA Poly(I:C) using a salmonid-specific microarray platform enriched with immune-related genes. Although the transcriptomic response measured as the total number of differentially expressed genes was higher in LPS, the intensity response, in terms of genes with a FC>2, was greater in Poly(I:C) treated cells. These two treatments shared the regulation of some genes, but not alls followed the same pattern. Over representation of Gene Ontology functional categories showed us that Poly(I:C) treatment produced a immune response whereas LPS stimulation affect biological processes specially. Trout erythrocytes were isolated from blood by twice Ficoll 1.007 density gradient centrifugations. For primary cell culture, erythrocytes were resuspended in DMEM (PAA Laboratories) supplemented with 10% heat-inactivated fetal bovine serum (FBS, PAA Laboratories) and the antibiotic Primocin (100 μg/ml, Invivogen) at a density of 7.5x106 cells/ml in six well cell culture plates (NUNC) and cultured at 18 ºC and 5% CO2. Erythrocytes were stimulated with LPS from E. coli (serotype 026:B6, Sigma) and Poly(I:C) (Invivogen) at 50 μg/ml, each treatment had their own control plate. All culture plates were incubated for 24h. Total RNA was extracted from the cultures using 1 ml of Tri Reagent (Sigma) following the manufacturer’s instructions with minor modifications. Quantity and integrity was analyzed by Experion RNA StdSens Analysis Kit (Bio-Rad). The design of the microarray posses 1818 genes printed in six replicates each, including random clones from common and subtracted cDNA libraries which were compared with known vertebrate proteins using blastx. The platform was enriched in immune-related genes.
Project description:The study investigated the acute and simultaneous response of the mammary and liver transcriptome to an intra-mammary lipopolysaccharide (LPS) challenge in early-lactating cows, and its consequences on metabolic biomarkers and liver composition. At 7 days of lactation, 7 cows served as controls (CTR) and 7 cows (LPS) received an intra-mammary E. coli LPS challenge. The mammary and liver tissues were sampled at 2.5 h from challenge for transcriptomic profiling. Liver composition was evaluated at 2.5 h and 7 d after challenge and blood biomarkers were analized at -2, 3, 7 and 14 d from challenge. In mammary tissue, the LPS challenge resulted in 189 differentially expressed gene (DEG), with 20 downregulated and 169 upregulated, while in the liver were found 107 DEG with 42 downregulated and 65 upregulated in LPS vs CTR. In the udder, the Dynamic Impact Approach (DIA) highlighted the activation of NOD-like receptor signaling, Toll-like receptor signaling, RIG-I-like receptor signaling and Apoptosis pathways, while in the liver were inhibited the Fatty acid elongation in mitochondria and activated the p53 signaling pathway. The LPS induced the alteration of liver lipid metabolism (rise of total lipid and triglyceride concentration), a systemic inflammation (rise of blood ceruloplasmin and bilirubin) and an increase of body fat mobilization. In cows subjected to intra-mammary LPS, the mammary gland responds activating mechanisms of pathogen recognition. In the liver the response likely depends by mediators coming from udder and affects the liver functionality and mainly the fatty acid metabolism. Fourteen Holstein cows entering their second or greater lactation were used. Cows were housed in a ventilated tie-stall barn and were fed a common lactation diet (Net energy of lactation = 1.69 Mcal/kg DM) as a total mixed ration once daily (0600 h) and milked twice daily (0400 and 1600 h). A bovine oligonucleotide (70-mers) microarray with >13,000 annotated sequences developed at the University of Illinois, was used for transcript profiling. Details on the development, annotation, and use of this microarray have been reported previously by Loor et al., 2007 (http://physiolgenomics.physiology.org/content/32/1/105.abstract). Methods for microarray hybridization and scanning were as reported by Loor et al. (2007). Briefly, slides were hydrated, dried, and placed in a UV Stratalinker 1800 (Stratagene, La Joya, CA) for ~5 min. Slides were washed with 0.2% SDS solution, rinsed with MilliQ (Millipore) H2O, and placed in warm prehybridization soln for 45 min at 42 C. The same amount of Cy3- or Cy5-labelled cDNA from mammary or liver and a reference standard RNA pool (made of different bovine tissues) were co-hybridized using a dye-swap design (i.e., two microarrays per sample). Slides were incubated for 48 h at 45 C prior to scanning. Criteria for evaluation of slide quality included: identification of number of spots with a minimum median signal intensity of 3 SD above background; keeping slides with a minimum of 20,000 spots with minimum median signal intensity of 3 SD above background in both Cy3 and Cy5 channels; and keeping slides with a minimum mean intensity of 400 relative fluorescent units in both Cy3 and Cy5 channels across the entire slide. Data from a total of 112 microarrays were normalized for dye and microarray effects (i.e., Lowess normalization and microarray centering) and used for statistical analysis. Data were analyzed using the Proc MIXED procedure of SAS (SAS, SAS Inst. Inc., Cary, NC). Fixed effects were treatment (LPS challenge, control (no infsuion)) and dye. Random effects included cow and microarray. Raw P values were adjusted using Benjamini and Hochberg’s false discovery rate (FDR). Differences in relative expression due to treatment were considered significant at an FDR-adjusted P < 0.05. For a more stringent characterization between the two treatments, a 1.5-fold difference in mRNA expression was set as threshold among differentially expressed genes.
Project description:To define the skeletal muscle adaptations induced by exercise performed at high altitude hypoxia, we investigated if the gene expression profile of Vastus lateralis muscle was affected by 5000 m-above-sl-expedition. Two-condition experiment, Vastus lateralis muscle biopsy post-expedition vs Vastus lateralis muscle biopsy pre-expedition. Five volunteers/climbers. Biological replicates: 1 pre-expedition sample, 1 post-expedition sample.
Project description:Juvenile rainbow trout were exposed to two different concentrations of 17β-estradiol (E2) (2 or 20 mg/kg feed), and then infected with three concentrations of Yersinia ruckeri, a bacterial pathogen causing massive losses in wild and farmed salmonid populations. Infection with Y. ruckeri caused mortality of trout, and this effect was significantly enhanced by simultaneous exposure to high E2 dose. Analysis of hepatic gene expression profiles revealed complex regulations of pathways involved in immune responses, stress responses and detoxicification pathways. E2 markedly reduced expression of several genes implicated in xenobiotic metabolism. The results suggest that the interaction between pathogen and E2 interfered with the fish’s capability of clearing toxic compounds. The findings of the current study add to our understanding of multiple exposure responses in fish. Microarray analyses compared 3 groups of pathogen infected fish: no estrogen treatment (NE2), low (LE2) and high (HE2) doses of hormone
Project description:The relevance of immune-endocrine interactions to the regulation of ovarian function in teleosts is virtually unexplored. As part of the innate immune response during infection, a number of cytokines such as tumor necrosis factor α (TNFα) and other immune factors, are produced and act on the reproductive system. However, TNFα is also an important physiological player in the ovulatory process in mammals. In the present study, we have examined for the first time the effects of TNFα in vitro in preovulatory ovarian follicles of a teleost fish, the brown trout (Salmo trutta). In control and recombinant trout TNFα (rtTNFα)-treated granulosa cells, we examined the percentage of apoptosis by flow cytometry analysis and cell viability by propidium iodide (PI) staining. Furthermore, we determined the in vitro effects of rtTNFα on follicle contraction and testosterone production in preovulatory trout ovarian follicles. In addition, we analyzed the gene expression profiles of control and rtTNFα-treated ovarian tissue by microarray and real-time PCR (qPCR) analyses.Treatment with rtTNFα induces ovarian cell apoptosis, decreases granulosa cell viability and stimulates the expression of genes known to be involved in the normal ovulatory process in trout. In addition, rtTNFα causes a significant increase in follicle contraction and testosterone production. Also, using a salmonid-specific microarray platform (SFA2.0 immunochip) we observed that rtTNFα induces the expression of genes known to be involved in inflammation, proteolysis and tissue remodeling. In view of these results, we propose that TNFα could have an important role in the biomechanics of follicle weakening, ovarian rupture and oocyte expulsion during ovulation in trout, primarily through its stimulation of follicular cell apoptosis and the expression of genes involved in follicle wall proteolysis and contraction. Reproductively mature female brown trout (Salmo trutta) from a cultured stock at the Piscifactoria de Bagà (Generalitat de Catalunya, Bagà, Spain) were kept under natural conditions of temperature and photoperiod. Fish at the preovulatory stage (according to the position of the germinal vesicle (GV) in oocytes that were cleared using a solution previously described), were anesthesized in 3-aminobenzoic acid ethyl ester (0.1 g/l; Sigma, Alcobendas, Spain) dissolved in fresh water, and the fish were sacrificed by concussion prior to the collection of the ovaries. The dissected ovaries were immediately used for the various in vitro assays. After dissection, brown trout preovulatory ovaries were placed in Hank´s balanced salt solution (HBSS) and individual ovarian follicles were manually separated with forceps from each ovary on ice, as previously described. To collect ovarian tissue for RNA extraction, preovulatory follicles from each of a total of three females were incubated (400 follicles/50 ml) in HBSS-BSA in the absence or presence of rtTNFα (100 ng/ ml, dissolved directly in HBSS-BSA), at 15ºC for 24 h with gentle shaking (100 rpm). At the end of the incubation follicles (previously de-yolked by gentle pressure) were removed, flash frozen in liquid nitrogen and stored at -80ºC until assayed.
Project description:The general objective of the study was to determine modulation of gene expression by environmental factors, with a special emphasis on bone formation. For this reason, the specific period of treatment was chosen between 5-6 days post-fertilization (dpf), when bone formation and calcification are taking place. We show that treatment with Para-Thyroid Hormone (PTH) causes a clear decrease of bone formation, as illustrated by cranial skeleton staining of the bone matrix by Alizarin Red, by morphometric analysis of the resulting images and by gene expression studies of selected genes. Thus, a whole genome micro-array experiment was conducted to identify genes that may be involved in the observed effect on bone formation.
Project description:The general objective of the study was to determine modulation of gene expression by environmental factors, with a special emphasis on bone formation. For this reason, the specific period of treatment was chosen between 5-6 days post-fertilization (dpf), when bone formation and calcification are taking place. We show that treatment with Vitamin D3 (VitD3) causes a clear increase of bone formation, as illustrated by cranial skeleton staining of the bone matrix by Alizarin Red, by morphometric analysis of the resulting images and by gene expression studies of selected genes. Thus, a whole genome micro-array experiment was conducted to identify genes that may be involved in the observed effect on bone formation.