Changes In Liver Transcriptome Research Articles

Liver transcriptome changes in pearl gentian grouper in response to acute high-temperature stress

Pearl gentian grouper is the main cultivated grouper variety along the southeast coast of China. However, the coastal waters often experience prolonged of high temperatures during summer due to global climate warming and frequent extreme high-temperature events near the coast. As a result, the high-temperature stress seriously hinders the development and growth of grouper aquaculture. In this study, SMRT-Seq and RNA-Seq sequencing techniques were used to analyze the gene expression changes in the pearl gentian grouper liver under room temperature (25 °C) and acute high temperatures (30, 34, 38, and 38 °C for 6 h). Based on the differential expression analysis, Short Time-series Expression Miner (STEM), and Weighted Gene Co-expression Network Analysis (WGCNA), 4144 differentially expressed genes (DEGs), two significantly expressed gene profiles (Profile0 and Profile19), and two high-temperature specific modules (Blue and Turquoise) were identified. The results revealed that the grouper responded to acute high-temperature stress by regulating genes enriched in biological processes, such as protein homeostasis, oxidative defense, apoptosis, and glucose and lipid metabolisms. Furthermore, 34 °C and 38 °C were confirmed as the key temperature points for the significant alterations in the physiological and metabolic processes of pearl gentian grouper under high-temperature stress, corresponding to the critical suitable growth temperature and high-temperature tolerance, respectively. The findings in this study provide a solid theoretical basis for understanding the high-temperature adaptation mechanism of pearl gentian grouper. They also provide important guidelines for promoting the development of the grouper aquaculture industry and molecular breeding high-temperature resistant grouper varieties.

Metabolism effector links in diet-induced and genetically-based obesity: A full-transcriptome study of liver tissue in experimental models in rodents

Background. When developing methods for personalized diet therapy of obesity, an urgent task is to study the molecular genetics features of the obesity pathogenesis using in vivo experimental models in laboratory animals.The aim. To determine metabolism effector links in obesity based on a comparative analysis of full-transcriptome profiles of the liver tissue of mice and rats of various strains.Materials and methods. We carried out a comparative analysis of the changes in liver transcriptome in rats and mice fed with diets of excessive energy value and exerting lipogenic effect. Data of full-transcriptome profiling using DNA microarray technology have been presented previously in 8 publications. Results. In three strains of mice treated with a high-carbohydrate high-fat diet (HCHFD), a significant differential expression (DE) of 1849 genes was revealed, of which 74 genes responded jointly in at least two groups of animals. In Wistar and Zuckerfa rats, 2109 genes responded to the consumption of HCHFD, of which 242 genes responded jointly in two groups of animals. For rodents different in genetic predisposition to the development of diet-induced obesity, the groups of genes that responded with the opposite sign of DE (depending on the genotype) in reaction to the consumption of HCHFD were identified. Bioinformatical analysis allowed establishing the presence of 43 metabolic pathways, which are targeted for the applied experimental diets exposure, in rats and 77 pathways – in mice. Four of these pathways – the pathway of retinoid metabolism, PPAR signaling pathway associated with it the previous one, xenobiotics metabolism and drugs metabolism mediated by cytochrome P450 system – responded in all groups of animals (except for female mice). The importance of the expression of Tat gene encoding tyrosine aminotransferase in the modulation of biogenic amines synthesis in diet-induced obesity was shown, which may represent a new neurometabolic regulatory function of the liver in response to the consumption of high-calorie diets. Conclusion. The analysis of the results of full-transcriptome studies showed that within each studied species (Rattus rattus and Mus domesticus) and animal sex, a number of genetic variants with a greater or lesser predisposition to the development of diet-induced obesity phenotype can be identified; and at the same time, within these variants, there is a largely similar pattern in the response of metabolism effector links to hypercaloric dietary intake. This pattern creates new prospects for translating the results of transcriptomic and metabolomic studies of laboratory animals into clinical practice in order to substantiate new approaches to personalized diet therapy of alimentary dependent diseases in patients with different genetic predisposition to obesity.

GC-MS Profile of Hua-Feng-Dan and RNA-Seq Analysis of Induced Adaptive Responses in the Liver.

Background: Hua-Feng-Dan is a patent Chinese medicine for stroke recovery and various diseases. This study used GC-MS to profile its ingredients and RNA-Seq to analyze the induced adaptive response in the liver. Methods: Hua-Feng-Dan was subjected to steam distillation and solvent extraction, followed by GC-MS analysis. Mice were orally administered Hua-Feng-Dan and its “Guide drug” Yaomu for 7 days. Liver pathology was examined, and total RNA isolated for RNA-Seq, followed by bioinformatic analysis and quantitative real-time PCR (qPCR). Results: Forty-four volatile and fifty liposoluble components in Hua-Feng-Dan were profiled and analyzed by the NIST library and their concentrations quantified. The major components (>1%) in volatile (5) and liposoluble (10) were highlighted. Hua-Feng-Dan and Yaomu at hepatoprotective doses did not produce liver toxicity as evidenced by histopathology and serum enzyme activities. GO Enrichment revealed that Hua-Feng-Dan affected lipid homeostasis, protein folding, and cell adhesion. KEGG showed activated cholesterol metabolism, bile secretion, and PPAR signaling pathways. Differentially expressed genes (DEGs) were identified by DESeq2 with p < 0.05 compared to controls. Hua-Feng-Dan produced more DEGs than Yaomu. qPCR on selected genes largely verified RNA-Seq results. Ingenuity Pathways Analysis of the upstream regulator revealed activation of MAPK and adaptive responses by Hua-Feng-Dan, and Yaomu was less effective. Hua-Feng-Dan-induced DEGs were highly correlated with the Gene Expression Omnibus database of chemical-induced adaptive transcriptome changes in the liver. Conclusion: GC-MS primarily profiled volatile and liposoluble components in Hua-Feng-Dan. Hua-Feng-Dan at the hepatoprotective dose did not produce liver pathological changes but induced metabolic and signaling pathway activations. The effects of Hua-Feng-Dan on liver transcriptome changes point toward induced adaptive responses to program the liver to produce hepatoprotective effects.

Effects of dietary protein levels on growth performance and liver transcriptome changes in juvenile top-mouth culter Erythroculter ilishaeformis

An eight-week growth experiment was conducted to investigate the growth performance and liver transcriptome response of juvenile top-mouth culter Erythroculter ilishaeformis fed with different dietary protein levels. Six isoenergetic diets supplemented with protein at a level of 25%, 30%, 35%, 40%, 45% and 50% were prepared. The fish (initial mean weight 6.27 ± 0.30 g, 35 fish per tank, n = 3) were fed the six test diets in a recirculating aquaculture system at 30 ± 2 °C. Our results showed that weight gain rate (WGR) increased from 161.88% to 247.20% with the increase of dietary protein level from 25% to 40%, and then kept nearly stabilized with further increases in dietary protein concentration. Feed conversion ratio (FCR) showed an opposite trend to WGR. Using WGR and FCR as the response criterion, the optimal protein requirement for maximum growth of this juvenile fish species was 41.14% and 43.75%, respectively. The liver transcriptome profiles using RNA-seq technology showed that a total of 189.13 million clean data was generated and 202,677 unigenes with 435,540 transcripts were assembled. Unigenes were then searched against four databases including Swiss-Prot, COG, KOG, and KEGG. Differentially expressed genes (DEGs) were considered as a threshold of the fold change (FC) ≥ 2 and a false discovery rate (FDR) ≤ 0.01 in a comparison. Trend analysis revealed that these DEGs were significantly clustered into five clusters. Several DEGs associated with growth (igf1 and ST), lipid metabolism (fasn and accα), glucose metabolism (pepck, pk, gk and g6pd), aspartate biosynthesis (AST), immune (MHC-II), were validated with qPCR analysis. Moreover, function analysis indicated that the DEGs were mainly involved in metabolism, immunity, antioxidation, and a variety of signal pathways. Taken together, our data provide a comprehensive understanding of the feed formulation and molecular mechanism underlying the effects of dietary protein on E. ilishaeformis.

The Hepatokine Adropin Is Regulated by Estrogen

Introduction: menopause is associated with weight gain, visceral adiposity and NAFLD. Rodent ovariectomy (OVX) is an accepted model for human menopause. Many OVX studies add high-fat diet or old-age to accentuate deranged phenotype. We have shown OVX alone induced weight gain and changes in liver transcriptome including downregulation of Enho, encoding for the hepatokine adropin (1). Here, we explore changes in VAT cytokine and adipokine genes, hepatic miRNA, and liver triglyceride content induced by OVX, in addition to estrogen’s role in regulation of adropin. Methods: 9-week-old C57BL/6J female mice underwent OVX or sham surgery. Groups of 10 mice were sacrificed at 6- and 12-weeks post-surgery and tissues harvested including mesenteric adipose tissue representing VAT. Liver TG was quantified using Cayman colorimetric assay. In-vitro studies performed in the murine hepatic cell-line, BNL1.ME. Adropin was measured using ELISA. Results: OVX induced adverse inflammatory cytokine & adipokine gene expression in VAT at 6-weeks post-surgery (Il18 1.1 p=0.01, Rares2 2.9, p=0.003, Retn 5.5, p=0.002) and 12-weeks post-surgery (Tnfa 2.3 p<0.001, Cxcl5 1.9 p=0.04). In the liver, OVX induced an increase in TG content at 12 weeks post-surgery (realtive increase vs sham 2.0 p=0.05). Hepatic Enho expression showed a strong inverse coorelation with total body weight gain (r= -0.7 p<0.001) and liver TG content (r=-0.4, p=0.04). In-vitro, estrogen induced an increase in Enho (relative mRNA change vs. growing medium 2.6, p=0.004); though protein level was unchanged, a trend for increased adropin was found in supernatant (relative change vs control 2.2 P=0.09). In-silico analysis of data from OVX mice treated with estrogen showed up-regulation of Enho (relative change vs vehicle, 6 p<0.001). At 6-weeks post-surgery OVX induced changes in hepatic miRNA profile with 48 miRNAs differentially expressed vs SHAM (24 up & 24 down). Integrating data from same sample RNA-SEQ and miRNA-SEQ created a network of differently expressed miRNA with oppositely differently expressed known specific mRNA targets. mIR-29, a known regulator of Enho in liver, was not found to be correlated with Enho expression in this context. Conclusions: OVX alone is sufficient to induce adverse changes in VAT gene expression and liver TG. Hepatic adropin gene expression is regulated by estrogen and its downregulation was strongly correlated to phenotypes relevant to menopause induced metabolic dysfunction, weight gain and increased liver fat. Thus, adropin should be further explored as a novel therapeutic and/or biomarker for menopause induced metabolic dysfunction. (1) Stokar, J., Gurt, I., Cohen-Kfir, E., Yakubovsky, O., Hanna, A., Assayag, E., & Dresner-Pollak, R. (2019). RNA-Seq Analysis of Ovariectomy-Induced Changes in Mouse Liver Reveals New Targets for Menopause-Associated Metabolic Derangement. Journal of the Endocrine Society, 3(Supplement_1), SUN-033.

Liver Transcriptome Changes of Hyla Rabbit in Response to Chronic Heat Stress.

Simple SummaryIt has been widely acknowledged in farm animals that environmental heat stress would have comprehensive influences on many kinds of physiological aspects, including the metabolic characteristics, production performances, welfare concerns, etc. The rabbit is a small herbivore and needs to regulate the body temperature in a fine mechanism. Little is known, however, about the genes and pathways that are involved in the regulatory responses under chronic heat stress conditions. In the present study, we investigated the liver transcriptome changes in response to chronic heat stress for Hyla rabbit, that is a commercial meat breed recently introduced into China. We successfully revealed the differentially expressed genes that were significantly enriched in heat stress related biological processes. The results would help us for better understanding the molecular mechanisms underlying physiological responses against heat stress in rabbits.Rabbit is an economically important farm animal in China and also is a widely used animal model in biological researches. Rabbits are very sensitive to the environmental conditions, therefore we investigated the liver transcriptome changes in response to chronic heat stress in the present study. Six Hyla rabbits were randomly divided into two groups: chronic heat stress (HS) and controls without heat stress (CN). Six RNA-Seq libraries totally yielded 380 million clean reads after the quality filtering. Approximately 85.07% of reads were mapped to the reference genome. After assembling transcripts and quantifying gene expression levels, we detected 51 differentially expressed genes (DEGs) between HS and CN groups with thresholds of the adjusted p-value < 0.05 and |log2(FoldChange)| > 1. Among them, 33 and 18 genes were upregulated and downregulated, respectively. Gene ontology analyses further revealed that these DEGs were mainly associated with metabolism of lipids, thyroid hormone metabolic process, and cellular modified amino acid catabolic process. The upregulated ACACB, ACLY, LSS, and CYP7A1 genes were found to be inter-related through biological processes of thioester biosynthetic process, acyl-CoA biosynthetic process, acetyl-CoA metabolic process, and others. Six DEGs were further validated by quantitative real-time PCR analysis. The results revealed the candidate genes and biological processes that will potentially be considered as important regulatory factors involved in the heat stress response in rabbits.

Changes in meta-transcriptome of rumen epimural microbial community and liver transcriptome in young calves with feed induced acidosis

The common management practices of dairy calves leads to increased starch concentration in feed, which subsequently may cause rumen acidosis while on milk and during weaning. Until recently, few attempts were undertaken to understand the health risks of prolonged ruminal acidosis in post weaning calves. Resultantly, the molecular changes in the digestive tracts in post-weaning calves with ruminal acidosis remain largely unexplored. In this study, we investigated the liver transcriptome changes along with its correlation with the rumen microbial rRNA expression changes in young calves using our model of feed induced ruminal acidosis. In this model, new born calves were fed a highly processed, starch-rich diet starting from one week of age through 16 weeks. A total of eight calves were involved in this study. Four of them were fed the acidosis-inducing diet (Treated) and the rest of the four were fed a standard starter diet (Control). Liver and rumen epithelial tissues were collected at necropsy at 17 weeks of age. Transcriptome analyses were carried out in the liver tissues and rRNA meta-transcriptome analysis were done using the rumen epithelial tissues. The correlation analysis was performed by comparing the liver mRNA expression with the rumen epithelial rRNA abundance at genus level. Calves with induced ruminal acidosis had significantly lower ruminal pH in comparison to the control group, in addition to significantly less weight-gain over the course of the experiment. In liver tissues, a total of 428 differentially expressed genes (DEGs) (fold-change, FC ≥ 1.5; adjusted P ≤ 0.1) were identified in treated group in comparison to control. Biological pathways enriched by these DEGs included cellular component organization, indicating the impact of ruminal acidosis on liver development in young calves. Specifically, the up-regulated genes were enriched in acute phase response (P < 0.01), pyruvate metabolic process (P < 0.01) and proton-acceptors (P ≪ 0.001), indicating the liver’s response to feed induced acidosis at the transcriptome level. Twelve transferase activity related genes had significant correlation with rumen microbial rRNA expression changes. Among these genes, two up-regulated genes were reported with involvement in lipid metabolism in the liver, implying the direct effect of feed-induced acidosis on both the rumen microbial community and liver metabolism. Our study provides insight into the physiological remodeling in the liver resultant from the prolonged acidosis in post weaning calves, which may facilitate future RNA-seq based diagnosis and precision management of rumen acidosis in dairy calves.

2020-P: Comparable Disease Progression in GAN and AMLN Diet-Induced Obese Mouse Models of Biopsy-Confirmed Nonalcoholic Steatohepatitis

Amylin Liver NASH (AMLN) diet-induced obese C57Bl/6J (DIO-NASH) and ob/ob (ob/ob-NASH) mouse models display clinical translatability with respect to metabolic and histopathological changes associated with nonalcoholic steatohepatitis (NASH). A recent FDA ban on trans-fats in foods has necessitated the development of a new NASH diet capable of promoting comparable disease, as AMLN diet contains trans-fat-containing Primex shortening. Here, we assessed the disease phenotype in C57Bl/6J and ob/ob mice fed a high-fat diet with a nutrient composition and caloric content comparable to the AMLN diet. Male ob/ob mice were fed AMLN diet (40% total fat kcal of which 18.5% were trans-fat kcal; 20% fructose; 2% cholesterol) for 16 weeks or a modified AMLN diet with Primex substituted by palm oil, termed Gubra Amylin NASH (GAN) diet, for up to 30 weeks. C57 mice were fed GAN diet for 28 weeks. In ob/ob-NASH mice, GAN diet was more obesogenic and adipogenic than the AMLN diet. GAN, but not AMLN, diet also impaired glucose tolerance in ob/ob-NASH mice versus chow-fed C57Bl/6J mice. Both diets promoted similar levels of steatosis, lobular inflammation and hepatocyte ballooning as well as similar fibrotic liver lesions and collagen-1a1 fractional area. Mild (stage F1) and moderate (stage F2) grade fibrosis was induced in DIO-NASH and ob/ob-NASH mice, respectively, when fed either diet for 16 weeks. When fed GAN diet for ≥24 weeks, a significant proportion of ob/ob-NASH mice developed advanced fibrosis (stage F3). The two diets also promoted overlapping liver transcriptome changes. In conclusion, AMLN diet modification by substitution of Primex with palm oil results in a preserved NASH phenotype in C57 and ob/ob mice. Accordingly, the GAN diet induced clear metabolic and histopathological hallmarks of biopsy-confirmed NASH in both DIO-NASH and ob/ob-NASH mice, highlighting the suitability of these models for the characterization of novel drug therapies for NASH. Disclosure B.B. Boland: Employee; Self; Gubra, MedImmune. H.H. Hansen: None. M. Boland: Employee; Self; Gubra, MedImmune. D. Oró: None. K.S. Tølbøl: None. S. Veidal: None. M. Feigh: None. J. Jelsing: Stock/Shareholder; Self; Gubra. N. Vrang: Board Member; Self; Gubra. Stock/Shareholder; Self; Gubra. J. Trevaskis: Employee; Self; Gilead Sciences, Inc., MedImmune. Stock/Shareholder; Self; AstraZeneca.

Transcriptomics analysis of host liver and meta-transcriptome analysis of rumen epimural microbial community in young calves treated with artificial dosing of rumen content from adult donor cow

In mammals, microbial colonization of the digestive tract (GIT) occurs right after birth by several bacterial phyla. Numerous human and mouse studies have reported the importance of early gut microbial inhabitants on host health. However, few attempts have been undertaken to directly interrogate the role of early gut/rumen microbial colonization on GIT development or host health in neonatal ruminants through artificial manipulation of the rumen microbiome. Thus, the molecular changes associated with bacterial colonization are largely unknown in cattle. In this study, we dosed young calves with exogenous rumen fluid obtained from an adult donor cow, starting at birth, and repeated every other week until six weeks of age. Eight Holstein bull calves were included in this study and were separated into two groups of four: the first group was treated with rumen content freshly extracted from an adult cow, and the second group was treated with sterilized rumen content. Using whole-transcriptome RNA-sequencing, we investigated the transcriptional changes in the host liver, which is a major metabolic organ and vital to the calf’s growth performance. Additionally, the comparison of rumen epimural microbial communities between the treatment groups was performed using the rRNA reads generated by sequencing. Liver transcriptome changes were enriched with genes involved in cell signaling and protein phosphorylation. Specifically, up-regulation of SGPL1 suggests a potential increase in the metabolism of sphingolipids, an essential molecular signal for bacterial survival in digestive tracts. Notably, eight genera, belonging to four phyla, had significant increases in abundance in treated calves. Our study provides insight into host liver transcriptome changes associated with early colonization of the microbial communities in neonatal calves. Such knowledge provides a foundation for future probiotics-based research in microbial organism mediated rumen development and nutrition in ruminants.

MicroRNAs mediate liver transcriptome changes upon soy diet intervention in mice.

Soy‐based diets have triggered the interest of the research community due to their beneficial effects on a wide variety of pathologies like breast and prostate cancer, diabetes and atherosclerosis. However, the molecular details underlying these effects are far from being completely understood; several recent attempts have been made to elucidate the soy‐induced liver transcriptome changes in different animal models. Here we used Next Generation Sequencing to identify a set of microRNAs specifically modulated by short‐term soy‐enriched diet in young male mice and estimated their impact on the liver transcriptome assessed by microarray. Clustering and topological community detection (CTCD) network analysis of STRING generated interactions of transcriptome data led to the identification of four topological communities of genes characteristically altered and putatively targeted by microRNAs upon soy diet intervention.

RNA-Seq analysis of transcriptome responses in Atlantic cod (Gadus morhua) precision-cut liver slices exposed to benzo[a]pyrene and 17α-ethynylestradiol

Polycyclic aromatic hydrocarbons such as benzo[a]pyrene (BaP) that activate the aryl hydrocarbon receptor (Ahr) pathway, and endocrine disruptors acting through the estrogen receptor pathway are among environmental pollutants of major concern. In this work, we exposed Atlantic cod (Gadus morhua) precision-cut liver slices (PCLS) to BaP (10 nM and 1000 nM), ethynylestradiol (EE2) (10 nM and 1000 nM), and equimolar mixtures of BaP and EE2 (10 nM and 1000 nM) for 48 h, and performed RNA-Seq based transcriptome mapping followed by systematic bioinformatics analyses. Our gene expression analysis showed that several genes were differentially expressed in response to BaP and EE2 treatments in PCLS. Strong up-regulation of genes coding for the cytochrome P450 1a (Cyp1a) enzyme and the Ahr repressor (Ahrrb) was observed in BaP treated PCLS. EE2 treatment of liver slices strongly up-regulated genes coding for precursors of vitellogenin (Vtg) and eggshell zona pellucida (Zp) proteins. As expected, pathway enrichment and network analysis showed that the Ahr and estrogen receptor pathways are among the top affected by BaP and EE2 treatments, respectively. Interestingly, two genes coding for fibroblast growth factor 3 (Fgf3) and fibroblast growth factor 4 (Fgf4) were up-regulated by EE2 in this study. To our knowledge, the fgf3 and fgf4 genes have not previously been described in relation to estrogen signaling in fish liver, and these results suggest the modulation of the FGF signaling pathway by estrogens in fish. The signature expression profiles of top differentially expressed genes in response to the single compound (BaP or EE2) treatment were generally maintained in the expression responses to the equimolar binary mixtures. However, in the mixture-treated groups, BaP appeared to have anti-estrogenic effects as observed by lower number of differentially expressed putative EE2 responsive genes. Our in-depth quantitative analysis of changes in liver transcriptome in response to BaP and EE2, using PCLS tissue culture provides further mechanistic insights into effects of the compounds. Moreover, the analyses demonstrate the usefulness of PCLS in cod for omics experiments.

Effects of crude oil exposure and elevated temperature on the liver transcriptome of polar cod (Boreogadus saida)

Petroleum-related activities in the Arctic have raised concerns about the adverse effects of potential oil spill on the environment and living organisms. Polar cod plays a key role in the Arctic marine ecosystem and is an important species for monitoring oil pollution in this region. We examined potential interactions of oil pollution and global warming by analysing liver transcriptome changes in polar cod exposed to crude oil at elevated temperature. Adult males and females were kept at high (11°C) or normal (4°C) temperature for 5 days before exposure to mechanically dispersed crude oil for 2 days followed by recovery in clean sea water for 11 days at the two temperatures. Genome-wide microarray analysis of liver samples revealed numerous differentially expressed genes induced by uptake of oil as confirmed by increased levels of bile polycyclic aromatic hydrocarbon (PAH) metabolites. The hepatic response included genes playing important roles in xenobiotic detoxification and closely related biochemical processes, but also of importance for protein stress response, cell repair and immunity. Though magnitude of transcriptome responses was similar at both temperatures, the upregulated expression of cyp1a1 and several chaperone genes was much stronger at 11°C. Most gene expression changes returned to basal levels after recovery. The microarray results were validated by qPCR measurement of eleven selected genes representing both known and novel biomarkers to assess exposure to anthropogenic threats on polar cod. Strong upregulation of the gene encoding fibroblast growth factor 7 is proposed to protect the liver of polar fish with aglomerular kidneys from the toxic effect of accumulated biliary compounds. The highly altered liver transcriptome patterns after acute oil exposure and recovery suggests rapid responses in polar cod to oil pollutants and the ability to cope with toxicity in relatively short time.

Liver transcriptome changes in zebrafish during acclimation to transport-associated stress.

Liver plays a key role during the stress acclimation, and liver transcriptome analysis of shipped zebrafish could reveal the molecular adjustments that occur in the organ. Transcriptional changes in liver were analyzed with a 44 K oligo array using total RNA from fish prior to transport and during a mock transport process - immediately after packing (0 h), at 48 and 72 h. Large numbers of genes related to a variety of biological processes and pathways were regulated, mainly during transport (at 48/72 h). Immediately after packing, transcripts of genes related to both gluconeogenesis and glycolysis were induced. During transport, induction of gluconeogenesis-linked genes and reduction of glycolysis-related genes may be supporting the increase in blood glucose levels. Inhibition of genes involved in fatty acid beta-oxidation may be pointing to the poor ability of fish to utilize energy from fatty acids, under transport conditions. Genes involved in some of the mechanisms that regulate body ammonia were also affected. Even though genes associated with certain transaminases were inhibited in liver, sustained glutamate deamination may have led to high ammonia accumulation in liver/body. Enhanced levels of gene transcripts in ubiquitination and MAPK signalling cascade and reduced levels of gene transcripts related to ROS generation via peroxisomal enzymes as well as xenobiotic metabolism may be signifying the importance of such cellular and tissue responses to maintain homeostasis. Furthermore, transcripts connected with stress and thyroid hormones were also regulated. Moreover, suppression of genes related to specific immune components may be denoting the deleterious impact of transport on fish health. Thus, this study has revealed the complex molecular -adjustments that occur in zebrafish when they are transported.

Changing Metabolic Signatures of Amino Acids and Lipids During the Prediabetic Period in a Pig Model With Impaired Incretin Function and Reduced β-Cell Mass

Diabetes is generally diagnosed too late. Therefore, biomarkers indicating early stages of β-cell dysfunction and mass reduction would facilitate timely counteraction. Transgenic pigs expressing a dominant-negative glucose-dependent insulinotropic polypeptide receptor (GIPRdn) reveal progressive deterioration of glucose control and reduction of β-cell mass, providing a unique opportunity to study metabolic changes during the prediabetic period. Plasma samples from intravenous glucose tolerance tests of 2.5- and 5-month-old GIPRdn transgenic and control animals were analyzed for 163 metabolites by targeted mass spectrometry. Analysis of variance revealed that 26 of 163 parameters were influenced by the interaction Genotype × Age (P ≤ 0.0001) and thus are potential markers for progression within the prediabetic state. Among them, the concentrations of seven amino acids (Phe, Orn, Val, xLeu, His, Arg, and Tyr) were increased in 2.5-month-old but decreased in 5-month-old GIPRdn transgenic pigs versus controls. Furthermore, specific sphingomyelins, diacylglycerols, and ether phospholipids were decreased in plasma of 5-month-old GIPRdn transgenic pigs. Alterations in plasma metabolite concentrations were associated with liver transcriptome changes in relevant pathways. The concentrations of a number of plasma amino acids and lipids correlated significantly with β-cell mass of 5-month-old pigs. These metabolites represent candidate biomarkers of early phases of β-cell dysfunction and mass reduction.

Role of Pituitary Hormones on 17α-Ethinylestradiol-Induced Cholestasis in Rat

Estrogens cause intrahepatic cholestasis in susceptible women during pregnancy, after administration of oral contraceptives, or during postmenopausal hormone replacement therapy. 17alpha-Ethinylestradiol (EE) is a synthetic estrogen widely used to cause experimental cholestasis in rodents with the aim of examining molecular mechanisms involved in this disease. EE actions on the liver are thought to be mediated by estrogen receptor alpha (ERalpha) and pituitary hormones. We tested this hypothesis by analyzing metabolic changes induced by EE in livers from hypophysectomized (HYPOX) and hypothyroid rats. Microarray studies revealed that the number of genes regulated by EE was increased almost 4-fold in HYPOX rat livers compared with intact males. Little overlap was apparent between the effects of EE in intact and HYPOX rats, demonstrating that pituitary hormones play a critical role in the hepatic effects of EE. Consistently, hypophysectomy protects the liver against induction by EE of serum bilirubin and alkaline phosphatase, two markers of cholestasis and hepatotoxicity and modulates the effects of EE on several genes involved in bile acid homeostasis (e.g., FXR, SHP, BSEP, and Cyp8b1). Finally, we demonstrate a novel mechanism of action of EE through binding and negative regulation of glucocorticoid receptor-mediated transcription. In summary, pituitary- and ERalpha-independent mechanisms contribute to development of EE-induced changes in liver transcriptome. Such mechanisms may be relevant when this model of EE-induced cholestasis is evaluated. The observation that the pharmacological effects of estrogen in liver differ in the absence or presence of the pituitary could be clinically relevant, because different drugs that block actions of pituitary hormones are now available.