Publications by authors named "Merete Fredholm"

100 Publications

Impaired NDRG1 functions in Schwann cells cause demyelinating neuropathy in a dog model of Charcot-Marie-Tooth type 4D.

Neuromuscul Disord 2021 01 26;31(1):56-68. Epub 2020 Nov 26.

Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ullevålsveien 72, 0454 Oslo, Norway.

Mutations in the N-myc downstream-regulated gene 1 (NDRG1) cause degenerative polyneuropathy in ways that are poorly understood. We have investigated Alaskan Malamute dogs with neuropathy caused by a missense mutation in NDRG1. In affected animals, nerve levels of NDRG1 protein were reduced by more than 70% (p< 0.03). Nerve fibers were thinly myelinated, loss of large myelinated fibers was pronounced and teased fiber preparations showed both demyelination and remyelination. Inclusions of filamentous material containing actin were present in adaxonal Schwann cell cytoplasm and Schmidt-Lanterman clefts. This condition strongly resembles the human Charcot-Marie-Tooth type 4D. However, the focally folded myelin with adaxonal infoldings segregating the axon found in this study are ultrastructural changes not described in the human disease. Furthermore, lipidomic analysis revealed a profound loss of peripheral nerve lipids. Our data suggest that the low levels of mutant NDRG1 is insufficient to support Schwann cells in maintaining myelin homeostasis.
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http://dx.doi.org/10.1016/j.nmd.2020.11.010DOI Listing
January 2021

Breeding schemes for intervertebral disc disease in dachshunds: Is disc calcification score preferable to genotyping of the FGF4 retrogene insertion on CFA12?

Canine Med Genet 2020 Dec 1;7(1):18. Epub 2020 Dec 1.

Department of Veterinary and Animal Sciences, University of Copenhagen, 1870, Frederiksberg C, Denmark.

Background: Approximately every fifth Dachshund is affected by disc herniation - a painful, hereditary condition which is typically preceded by disc calcification. Therefore, the selection of dogs suitable for breeding can be based on radiographic examination of calcification status. Recently, an insertion of an FGF4 retrogene on CFA12 has been identified and associated with the risk of developing disc herniation in chondrodystrophic breeds and a DNA test is now offered. In this study we investigate the incidence of disc herniation in the smooth-haired, long-haired and wire- haired Dachshund populations. We also evaluate and compare the accuracy of the two breeding schemes predicting the risk of disc herniation: the DNA test and the radiography based scheme.

Results: The overall incidence of disc herniation in Danish Dachshunds was 18% and no significant difference was found between the long-haired (17%), smooth-haired (22%) and wire-haired (16%) populations (p > 0.05). We found a significant association (p <  0.0001) between calcification status and the risk of disc herniation with a relative risk of 14.78. Using calcification status (≥ 5 or <  5 calcifications) as a risk indicator has a sensitivity of 0.79 and a specificity of 0.91. A significant association between the FGF4 retrogene insertion and the disc calcification status was found in the wire-haired population (p <  0.0001) where the DNA test has a sensitivity of 1.0 and a specificity of 0.14. In the long- and smooth-haired populations no association was found (p > 0.05) and here the insertion allele was almost fixed.

Conclusion: Our results show that the FGF4 retrogene insertion on CFA12 is not a valid risk indicator on its own. Relying on the DNA test will have an irreversible effect on the Dachshund breed excluding almost all dogs from breeding. Thus, using calcification status remains the most reliable breeding scheme for disc herniation in Dachshunds.
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http://dx.doi.org/10.1186/s40575-020-00096-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7708201PMC
December 2020

Inclusion of endophenotypes in a standard GWAS facilitate a detailed mechanistic understanding of genetic elements that control blood lipid levels.

Sci Rep 2020 10 28;10(1):18434. Epub 2020 Oct 28.

Animal Genetics, Bioinformatics and Breeding, Department of Veterinary and Animal Sciences, University of Copenhagen, Gronnegaardsvej 3, 1870, Frederikgsberg C, Denmark.

Dyslipidemia is the primary cause of cardiovascular disease, which is a serious human health problem in large parts of the world. Therefore, it is important to understand the genetic and molecular mechanisms that regulate blood levels of cholesterol and other lipids. Discovery of genetic elements in the regulatory machinery is often based on genome wide associations studies (GWAS) focused on end-point phenotypes such as total cholesterol level or a disease diagnosis. In the present study, we add endophenotypes, such as serum levels of intermediate metabolites in the cholesterol synthesis pathways, to a GWAS analysis and use the pig as an animal model. We do this to increase statistical power and to facilitate biological interpretation of results. Although the study population was limited to ~ 300 individuals, we identify two genome-wide significant associations and ten suggestive associations. Furthermore, we identify 28 tentative associations to loci previously associated with blood lipids or dyslipidemia associated diseases. The associations with endophenotypes may inspire future studies that can dissect the biological mechanisms underlying these previously identified associations and add a new level of understanding to previously identified associations.
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http://dx.doi.org/10.1038/s41598-020-75612-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7595098PMC
October 2020

FGF21 regulates hepatic metabolic pathways to improve steatosis and inflammation.

Endocr Connect 2020 Aug;9(8):755-768

Global Obesity and Liver Disease Research, Novo Nordisk A/S, Måløv, Denmark.

The prevalence of non-alcoholic fatty liver disease (NAFLD) has increased dramatically worldwide and, subsequently, also the risk of developing non-alcoholic steatohepatitis (NASH), hepatic fibrosis, cirrhosis and cancer. Today, weight loss is the only available treatment, but administration of fibroblast growth factor 21 (FGF21) analogues have, in addition to weight loss, shown improvements on liver metabolic health but the mechanisms behind are not entirely clear. The aim of this study was to investigate the hepatic metabolic profile in response to FGF21 treatment. Diet-induced obese (DIO) mice were treated with s.c. administration of FGF21 or subjected to caloric restriction by switching from high fat diet (HFD) to chow to induce 20% weight loss and changes were compared to vehicle dosed DIO mice. Cumulative caloric intake was reduced by chow, while no differences were observed between FGF21 and vehicle dosed mice. The body weight loss in both treatment groups was associated with reduced body fat mass and hepatic triglycerides (TG), while hepatic cholesterol was slightly decreased by chow. Liver glycogen was decreased by FGF21 and increased by chow. The hepatic gene expression profiles suggest that FGF21 increased uptake of fatty acids and lipoproteins, channeled TGs toward the production of cholesterol and bile acid, reduced lipogenesis and increased hepatic glucose output. Furthermore, FGF21 appeared to reduce inflammation and regulate hepatic leptin receptor-a expression. In conclusion, FGF21 affected several metabolic pathways to reduce hepatic steatosis and improve hepatic health and markedly more genes than diet restriction (61 vs 16 out of 89 investigated genes).
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http://dx.doi.org/10.1530/EC-20-0152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7424338PMC
August 2020

Genomic diversity revealed by whole-genome sequencing in three Danish commercial pig breeds.

J Anim Sci 2020 Jul;98(7)

Center for Quantitative Genetics and Genomics, Faculty of Technical Sciences, Aarhus University, Tjele, Denmark.

Whole-genome sequencing of 217 animals from three Danish commercial pig breeds (Duroc, Landrace [LL], and Yorkshire [YY]) was performed. Twenty-six million single-nucleotide polymorphisms (SNPs) and 8 million insertions or deletions (indels) were uncovered. Among the SNPs, 493,099 variants were located in coding sequences, and 29,430 were predicted to have a high functional impact such as gain or loss of stop codon. Using the whole-genome sequence dataset as the reference, the imputation accuracy for pigs genotyped with high-density SNP chips was examined. The overall average imputation accuracy for all biallelic variants (SNP and indel) was 0.69, while it was 0.83 for variants with minor allele frequency > 0.1. This study provides whole-genome reference data to impute SNP chip-genotyped animals for further studies to fine map quantitative trait loci as well as improving the prediction accuracy in genomic selection. Signatures of selection were identified both through analyses of fixation and differentiation to reveal selective sweeps that may have had prominent roles during breed development or subsequent divergent selection. However, the fixation indices did not indicate a strong divergence among these three breeds. In LL and YY, the integrated haplotype score identified genomic regions under recent selection. These regions contained genes for olfactory receptors and oxidoreductases. Olfactory receptor genes that might have played a major role in the domestication were previously reported to have been under selection in several species including cattle and swine.
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http://dx.doi.org/10.1093/jas/skaa229DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7394143PMC
July 2020

Arctic-adapted dogs emerged at the Pleistocene-Holocene transition.

Science 2020 06;368(6498):1495-1499

The GLOBE Institute, University of Copenhagen, Copenhagen, Denmark.

Although sled dogs are one of the most specialized groups of dogs, their origin and evolution has received much less attention than many other dog groups. We applied a genomic approach to investigate their spatiotemporal emergence by sequencing the genomes of 10 modern Greenland sled dogs, an ~9500-year-old Siberian dog associated with archaeological evidence for sled technology, and an ~33,000-year-old Siberian wolf. We found noteworthy genetic similarity between the ancient dog and modern sled dogs. We detected gene flow from Pleistocene Siberian wolves, but not modern American wolves, to present-day sled dogs. The results indicate that the major ancestry of modern sled dogs traces back to Siberia, where sled dog-specific haplotypes of genes that potentially relate to Arctic adaptation were established by 9500 years ago.
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http://dx.doi.org/10.1126/science.aaz8599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7116267PMC
June 2020

NASH-inducing Diets in Göttingen Minipigs.

J Clin Exp Hepatol 2020 May-Jun;10(3):211-221. Epub 2019 Sep 21.

Global Drug Discovery, Novo Nordisk A/S, Maaloev, Denmark.

Background: Owing to the human-like physiology, a minipig model of nonalcoholic steatohepatitis (NASH) could be valuable. Pigs, however, rarely develop substantial hepatic steatosis, even when fed diets with high fat, fructose, and cholesterol (FFC) content. The potential of choline-deficient, amino acid-defined high-fat diets (CDAHFD) was therefore evaluated in Göttingen Minipigs.

Methods: Castrated male Göttingen Minipigs were fed either chow (n = 5) or one of the three NASH diets: FFC (n = 5), CDAHFD with sucrose (CDAHFD-S; n = 4), or fructose (CDAHFD-F; n = 4) for 8 weeks. Liver and blood samples were collected after 2 weeks and at termination.

Results: Compared with chow, the body weight was higher after FFC (9.8 ± 0.4 versus 8.5 ± 1.2 kg; mean ± SD) and less after CDAHFD-S (6.4 ± 0.8 kg) and CDAHFD-F (6.9 ± 0.8 kg). Liver weight per kg body weight was significantly increased in all 3 NASH groups (FFC 2.1 times; and both CDAHFD diets 3.1 times). Histologically, pronounced macrovesicular steatosis developed only in the CDAHFD groups. Inflammation was present in all three NASH groups. In the CDAHFD groups, inflammatory cells formed crown-like structures around steatotic hepatocytes. Sirius red staining revealed mild fibrosis in the two CDAHFD groups with the fibrotic potential being further supported by immunohistochemical staining for activated stellate cells and gene expression analyses. No noticeable differences were found between CDAHFD-S and CDAHFD-F.

Conclusions: Göttingen Minipigs fed CDAHFD developed pronounced steatosis with inflammation around steatotic hepatocytes and incipient fibrosis, thereby showing potential as a model for human NASH. Further studies are needed to investigate the period needed for marked fibrosis to develop.
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http://dx.doi.org/10.1016/j.jceh.2019.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7212300PMC
September 2019

Genome wide association study of 40 clinical measurements in eight dog breeds.

Sci Rep 2020 04 16;10(1):6520. Epub 2020 Apr 16.

Unit of Animal Genomics, GIGA Institute, University of Liège, Liège, Belgium.

The domestic dog represents an ideal model for identifying susceptibility genes, many of which are shared with humans. In this study, we investigated the genetic contribution to individual differences in 40 clinically important measurements by a genome-wide association study (GWAS) in a multinational cohort of 472 healthy dogs from eight breeds. Meta-analysis using the binary effects model after breed-specific GWAS, identified 13 genome-wide significant associations, three of them showed experimental-wide significant associations. We detected a signal at chromosome 13 for the serum concentration of alanine aminotransferase (ALT) in which we detected four breed-specific signals. A large proportion of the variance of ALT (18.1-47.7%) was explained by this locus. Similarly, a single SNP was also responsible for a large proportion of the variance (6.8-78.4%) for other measurements such as fructosamine, stress during physical exam, glucose, and morphometric measurements. The genetic contribution of single variant was much larger than in humans. These findings illustrate the importance of performing meta-analysis after breed-specific GWAS to reveal the genetic contribution to individual differences in clinically important measurements, which would lead to improvement of veterinary medicine.
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http://dx.doi.org/10.1038/s41598-020-63457-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7162946PMC
April 2020

The expression signatures in liver and adipose tissue from obese Göttingen Minipigs reveal a predisposition for healthy fat accumulation.

Nutr Diabetes 2020 03 23;10(1). Epub 2020 Mar 23.

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 1870, Frederiksberg, Denmark.

Background: Model animals are valuable resources for dissecting basic aspects of the regulation of obesity and metabolism. The translatability of results relies on understanding comparative aspects of molecular pathophysiology. Several studies have shown that despite the presence of overt obesity and dyslipidemia in the pig key human pathological hepatic findings such as hepatocellular ballooning and abundant steatosis are lacking in the model.

Objectives: The aim of this study was to elucidate why these histopathological characteristics did not occur in a high fat, fructose and cholesterol (FFC) diet-induced obese Göttingen Minipig model.

Methods: High-throughput expression profiling of more than 90 metabolically relevant genes was performed in liver, subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) of male minipigs diet fed: standard chow (SD, n = 7); FFC diet (n = 14); FFC diet in streptozotocin-induced diabetic pigs (FFC, n = 8). Moreover, histopathological assessment of SAT and VAT was performed.

Results: 12, 4 and 1 genes were highly significantly differentially expressed in liver, SAT and VAT when comparing the FFC and SD groups whereas the corresponding numbers were 15, 2, and 1 when comparing the FFC and SD groups. Although the minipigs in both FFC groups developed sever obesity and dyslipidemia, the insulin-signaling pathways were not affected. Notably, four genes involved in lipid acquisition and removal, were highly deregulated in the liver: PPARG, LPL, CD36 and FABP4. These genes have been reported to play a major role in promoting hepatic steatosis in rodents and humans. Since very little macrophage-associated pro-inflammatory response was detected in the adipose tissues the expansion appears to have no adverse impact on adipose tissue metabolism.

Conclusion: The study shows that morbidly obese Göttingen Minipigs are protected against many of the metabolic and hepatic abnormalities associated with obesity due to a remarkable ability to expand the adipose compartments to accommodate excess calories.
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http://dx.doi.org/10.1038/s41387-020-0112-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7090036PMC
March 2020

Epigenetic and Transcriptomic Characterization of Pure Adipocyte Fractions From Obese Pigs Identifies Candidate Pathways Controlling Metabolism.

Front Genet 2019 17;10:1268. Epub 2019 Dec 17.

Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

Reprogramming of adipocyte function in obesity is implicated in metabolic disorders like type 2 diabetes. Here, we used the pig, an animal model sharing many physiological and pathophysiological similarities with humans, to perform in-depth epigenomic and transcriptomic characterization of pure adipocyte fractions. Using a combined DNA methylation capture sequencing and Reduced Representation bisulfite sequencing (RRBS) strategy in 11 lean and 12 obese pigs, we identified in 3529 differentially methylated regions (DMRs) located at close proximity to-, or within genes in the adipocytes. By sequencing of the transcriptome from the same fraction of isolated adipocytes, we identified 276 differentially expressed transcripts with at least one or more DMR. These transcripts were over-represented in gene pathways related to MAPK, metabolic and insulin signaling. Using a candidate gene approach, we further characterized 13 genes potentially regulated by DNA methylation and identified putative transcription factor binding sites that could be affected by the differential methylation in obesity. Our data constitute a valuable resource for further investigations aiming to delineate the epigenetic etiology of metabolic disorders.
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http://dx.doi.org/10.3389/fgene.2019.01268DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6927937PMC
December 2019

Breeding French bulldogs so that they breathe well-A long way to go.

PLoS One 2019 16;14(12):e0226280. Epub 2019 Dec 16.

Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark.

Brachycephalic syndrome (BS) is a pathophysiological disorder caused by excessive soft tissue within the upper airways of short-nosed dog breeds, causing obstruction of the nasal, pharyngeal and laryngeal lumen, resulting in severe respiratory distress. As the prevalence of BS appears to be high among some of the affected breeds, there is an urgent need for breeding efforts to improve the health status of those dogs. In the present study, we evaluated correlations between morphometric and other phenotypic characteristics and BS in a population of 69 French bulldogs from Denmark to identify parameters that could serve as a basis for breeding against BS. Furthermore, the genetic variation was monitored to determine whether it would be possible to breed based on these characteristics without simultaneously causing a critical reduction in genetic variation. Six phenotypic characteristics were correlated with the Brachycephalic Syndrome Functional (BSF) score. Among the morphometric risk factors, nostril stenosis (NS) and neck girth (NG) had the highest impact on the BSF score, accounting for 32% and 4% of the variation, respectively. The genetic variation in the population was comparable to other pure breeds, i.e. estimated and observed heterozygosity was 0.60 and the average inbreeding coefficient was 0.01. If only dogs with Grades 1 and 2 NS (no or only mild NS) were selected for breeding the mean BSF score would be reduced significantly. However, it would result in the exclusion of 81% of the population for breeding and this is not prudent. Excluding only dogs with severe stenosis (Grade 4) would exclude 50% of the population without any adverse impact on genetic variation within the population. Although exclusion of dogs with Grade 4 would result in an apparent reduction in the mean BSF score, this reduction is not significant. As NS accounts for 32% of the variation in BSF score, a possible long term strategy to reduce the prevalence of the BS in French bulldogs would seem to be a selection scheme that first excluded dogs with the most severe NS from breeding, gradually moving towards selecting dogs with lower NS grades. According to our findings there is no viable short term solution for reducing the prevalence of BS in the French bulldog population.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0226280PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913956PMC
April 2020

Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic.

Proc Biol Sci 2019 12 27;286(1916):20191929. Epub 2019 Nov 27.

Institut des Sciences de l'Evolution-Montpellier, CNRS, Université de Montpellier, IRD, EPHE, Montpellier, Occitanie, France.

Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.
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http://dx.doi.org/10.1098/rspb.2019.1929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6939252PMC
December 2019

Evaluation of fecal microRNA stability in healthy cats.

Vet Clin Pathol 2019 Sep 26;48(3):455-460. Epub 2019 Jun 26.

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

Background: Gastrointestinal (GI) cancer accounts for 14% of feline malignancies. There is a great need for reliable noninvasive diagnostic biomarkers to reach a timely diagnosis and initiate treatment. Fecal microRNAs (miRNAs) could be such a biomarker and have shown great potential in colorectal screening in people but have yet to be investigated in cats.

Objectives: We aimed to evaluate the presence and stability of feline fecal miRNA under different storage conditions (room temperature [RT], 4, and -20°C) and to evaluate the expression levels of specific fecal miRNAs collected on three separate days (days 1, 4, and 7) in healthy cats.

Methods: Healthy cats were prospectively recruited. Fecal samples were collected, aliquoted, and stored for 24 hours at RT and then transferred to -20°C, stored for 24 hours at 4°C and then transferred to -20°C, or were immediately placed at -20°C on day 1 or at -20°C on days 4 and 7 postcollection. Expression of 22 miRNAs was investigated using quantitative real-time PCR.

Results: Ten miRNA assays worked well, and one, let-7b, was used for normalization. No differences in miRNA expression were seen between the three storage temperatures for the nine miRNAs investigated. Only miR-26a showed a significant increase in expression between samples of days 1 and 7. The rest of the miRNAs levels were stable over time.

Conclusions: Fecal miRNA can be isolated from healthy cats. The expression was stable at different temperatures and for most of the miRNAs over time. Prospective studies evaluating fecal miRNA as biomarkers in cats with GI neoplasia are warranted.
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http://dx.doi.org/10.1111/vcp.12757DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6852515PMC
September 2019

Exploration of extracellular vesicles from provides evidence of parasite-host cross talk.

J Extracell Vesicles 2019 14;8(1):1578116. Epub 2019 Feb 14.

Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark.

The prevalent porcine helminth, , compromises pig health and reduces farm productivity worldwide. The closely related human parasite, , infects more than 800 million people representing a disease burden of 1.31 million disability-adjusted life years. The infections are often chronic in nature, and the parasites have a profound ability to modulate their hosts' immune responses. This study provides the first in-depth characterisation of extracellular vesicles (EVs) from different developmental stages and body parts of and proposes the role of these vesicles in the host-parasite interplay. The release of EVs from the third- (L3) and fourth-stage (L4) larvae and adults was demonstrated by transmission electron microscopy (TEM), and sequencing of EV-derived RNA identified a number of microRNAs (miRNAs) and transcripts of potential host immune targets, such as IL-13, IL-25 and IL-33, were identified. Furthermore, proteomics of EVs identified several proteins with immunomodulatory properties and other proteins previously shown to be associated with parasite EVs. Taken together, these results suggest that EVs and their cargo may play a role in host-parasite interactions. This knowledge may pave the way to novel strategies for helminth infection control and knowledge of their immune modulatory potential.
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http://dx.doi.org/10.1080/20013078.2019.1578116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6383609PMC
February 2019

Interbreed variation of biomarkers of lipid and glucose metabolism in dogs.

Vet Clin Pathol 2018 Dec 17;47(4):582-588. Epub 2018 Dec 17.

University of Liège, Liège, Belgium.

Background: Markers of lipid and glucose metabolism are used in both clinical practice and research. Detection of abnormal laboratory results often relies on species-specific reference intervals, but interbreed variation can also affect data interpretation.

Objectives: The purpose of the present study was to compare concentrations of selected biochemical variables among different dog breeds.

Methods: We analyzed a database containing information on biochemical variables from 534 dogs belonging to nine different breeds. All dogs were confirmed to be healthy based on history, physical examination, and ancillary tests. Concentrations of glucose, fructosamine, insulin, cholesterol, triglycerides, fatty acids, and C-reactive protein were compared using the nonparametric Kruskal-Wallis and Dunn's tests.

Results: All variables tested showed significant interbreed differences, although all breeds remained within the previously established RIs for dogs. Fructosamine, insulin, and cholesterol showed a wide interbreed variation that could affect the interpretation of results.

Conclusions: Breed is an important factor to consider when assessing energy metabolism in dogs, especially for markers like fructosamine, insulin, and cholesterol, which vary considerably among breeds.
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http://dx.doi.org/10.1111/vcp.12673DOI Listing
December 2018

Early microbial colonization affects DNA methylation of genes related to intestinal immunity and metabolism in preterm pigs.

DNA Res 2018 Jan 19. Epub 2018 Jan 19.

Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.

Epigenetic regulation may play an important role in mediating microbe-host interactions and adaptation of intestinal gene expression to bacterial colonization just after birth. This is particularly important after preterm birth because the immature intestine is hypersensitive to invading bacteria. We compared the intestinal DNA methylome and microbiome between conventional (CON) and antibiotics-treated (AB) preterm pigs, used as a model for preterm infants. Oral AB treatment reduced bacterial density (∼100-fold), diversity and fermentation, improved the resistance to necrotizing enterocolitis (NEC) and changed the genome-wide DNA methylation in the distal small intestine. Integration of epigenome data with previously obtained proteome data showed that intestinal immune-metabolic pathways were affected by the AB-induced delay in bacterial colonization. DNA methylation and expression of intestinal genes, related to innate immune response, phagocytosis, endothelial homeostasis and tissue metabolism (e.g. CPN1, C3, LBP, HIF1A, MicroRNA-126, PTPRE), differed between AB and CON pigs even before any evidence of NEC lesions. Our findings document that the newborn immature intestine is influenced by bacterial colonization via DNA methylation changes. Microbiota-dependent epigenetic programming of genes related to gut immunity, vascular integrity and metabolism may be critical for short- and long-term intestinal health in preterm neonates.
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http://dx.doi.org/10.1093/dnares/dsy001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014285PMC
January 2018

Ascaris Suum Infection Downregulates Inflammatory Pathways in the Pig Intestine In Vivo and in Human Dendritic Cells In Vitro.

J Infect Dis 2018 01;217(2):310-319

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.

Ascaris suum is a helminth parasite of pigs closely related to its human counterpart, A. lumbricoides, which infects almost 1 billion people. Ascaris is thought to modulate host immune and inflammatory responses, which may drive immune hyporesponsiveness during chronic infections. Using transcriptomic analysis, we show here that pigs with a chronic A. suum infection have a substantial suppression of inflammatory pathways in the intestinal mucosa, with a broad downregulation of genes encoding cytokines and antigen-processing and costimulatory molecules. A. suum body fluid (ABF) suppressed similar transcriptional pathways in human dendritic cells (DCs) in vitro. DCs exposed to ABF secreted minimal amounts of cytokines and had impaired production of cyclooxygengase-2, altered glucose metabolism, and reduced capacity to induce interferon-gamma production in T cells. Our in vivo and in vitro data provide an insight into mucosal immune modulation during Ascaris infection, and show that A. suum profoundly suppresses immune and inflammatory pathways.
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http://dx.doi.org/10.1093/infdis/jix585DOI Listing
January 2018

Deregulation of obesity-relevant genes is associated with progression in BMI and the amount of adipose tissue in pigs.

Mol Genet Genomics 2018 Feb 14;293(1):129-136. Epub 2017 Sep 14.

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 3, 1870, Frederiksberg C, Denmark.

The aim of this study was to elucidate the relative impact of three phenotypes often used to characterize obesity on perturbation of molecular pathways involved in obesity. The three obesity-related phenotypes are (1) body mass index (BMI), (2) amount of subcutaneous adipose tissue (SATa), and (3) amount of retroperitoneal adipose tissue (RPATa). Although it is generally accepted that increasing amount of RPATa is 'unhealthy', a direct comparison of the relative impact of the three obesity-related phenotypes on gene expression has, to our knowledge, not been performed previously. We have used multiple linear models to analyze altered gene expression of selected obesity-related genes in tissues collected from 19 female pigs phenotypically characterized with respect to the obesity-related phenotypes. Gene expression was assessed by high-throughput qPCR in RNA from liver, skeletal muscle and abdominal adipose tissue. The stringent statistical approach used in the study has increased the power of the analysis compared to the classical approach of analysis in divergent groups of individuals. Our approach led to the identification of key components of cellular pathways that are modulated in the three tissues in association with changes in the three obesity-relevant phenotypes (BMI, SATa and RPATa). The deregulated pathways are involved in biosynthesis and transcript regulation in adipocytes, in lipid transport, lipolysis and metabolism, and in inflammatory responses. Deregulation seemed more comprehensive in liver (23 genes) compared to abdominal adipose tissue (10 genes) and muscle (3 genes). Notably, the study supports the notion that excess amount of intra-abdominal adipose tissue is associated with a greater metabolic disease risk. Our results provide molecular support for this notion by demonstrating that increasing amount of RPATa has a higher impact on perturbation of cellular pathways influencing obesity and obesity-related metabolic traits compared to increase in BMI and amount of SATa.
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http://dx.doi.org/10.1007/s00438-017-1369-2DOI Listing
February 2018

Haplotypes on pig chromosome 3 distinguish metabolically healthy from unhealthy obese individuals.

PLoS One 2017 1;12(6):e0178828. Epub 2017 Jun 1.

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

We have established a pig resource population specifically designed to elucidate the genetics involved in development of obesity and obesity related co-morbidities by crossing the obesity prone Göttingen Minipig breed with two lean production pig breeds. In this study we have performed genome wide association (GWA) to identify loci with effect on blood lipid levels. The most significantly associated single nucleotide polymorphisms (SNPs) were used for linkage disequilibrium (LD) and haplotype analyses. Three separate haploblocks which influence the ratio between high density lipoprotein cholesterol and total cholesterol (HDL-C/CT), triglycerides (TG) and low density lipoprotein cholesterol (LDL-C) levels respectively were identified on Sus Scrofa chromosome 3 (SSC3). Large additive genetic effects were found for the HDL-C/CT and LDL-C haplotypes. Haplotypes segregating from Göttingen Minipigs were shown to impose a positive effect on blood lipid levels. Thus, the genetic profile of the Göttingen Minipig breed seems to support a phenotype comparable to the metabolic healthy obese (MHO) phenotype in humans.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0178828PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5453593PMC
September 2017

Re-emergence of hereditary polyneuropathy in Scandinavian Alaskan malamute dogs-old enemy or new entity? A case series.

Acta Vet Scand 2017 May 2;59(1):26. Epub 2017 May 2.

Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 8146, 0033, Oslo, Norway.

A homozygous mutation has been identified in the N-myc downstream-regulated gene 1 (NDRG1) in recent cases of polyneuropathy in Alaskan malamute dogs from the Nordic countries and USA. The objective of the present study was to determine if cases diagnosed 30-40 years ago with polyneuropathy in the Alaskan malamute breed in Norway had the same hereditary disease as the recent cases. Fourteen historical cases and 12 recently diagnosed Alaskan malamute dogs with hereditary polyneuropathy, and their parents and littermates (n = 88) were included in this study (total n = 114). After phenotyping of historical and recent cases, NDRG1 genotyping was performed using DNA extracted from archived material from five Norwegian dogs affected by the disease in the late 1970s and 1980s. In addition, pedigrees were analysed. Our study concluded that historical and recent phenotypic polyneuropathy cases were carrying the same NDRG1-mutation. The pedigree analysis showed that all affected Alaskan malamute cases with polyneuropathy could be traced back to one common ancestor of North American origin. By this study, a well-documented example of the silent transmission of recessive disease-causing alleles through many generations is provided, demonstrated by the re-emergence of a phenotypically and genetically uniform entity in the Scandinavian Alaskan malamute population.
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http://dx.doi.org/10.1186/s13028-017-0295-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414310PMC
May 2017

Fat and carbohydrate content in the diet induces drastic changes in gene expression in young Göttingen minipigs.

Mamm Genome 2017 06 10;28(5-6):166-175. Epub 2017 Apr 10.

Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.

In human health, there is interest in developing specific diets to reduce body weight. These studies are mainly focused on phenotypic changes induced in blood measurements, i.e., triglycerides, HDL, LDL, and insulin, and on physical changes, i.e., body weight and BMI. To evaluate the biological impact of diet interventions, it is very important to investigate the molecular mechanisms driving the diet-induced phenotypic changes in relevant tissues. However, studying these effects in humans is difficult due to ethical concerns in doing interventions and obtaining tissue samples and good animal models are therefore needed. Göttingen minipigs, a small size obesity prone pig breed, have previously been shown to be a useful translational animal model for metabolic studies. In this study, 16 Göttingen minipig males (2-month old) were submitted to 13 weeks of differential diets to investigate the initial stages of diet-induced metabolic changes. Half of them were fed a high-fat/cholesterol, low-carbohydrate (HFLC) diet, and the other half were fed a low- fat/cholesterol, high-carbohydrate (LFHC) diet. After 13 weeks, the HFLC group weighted less and had dyslipidemia compared to the LFHC group. Liver, pancreas, and adipose tissues were collected at slaughter. Gene expression profiling of 83 metabolism-relevant genes was performed using high-throughput qPCR. In total, 41 genes were deregulated in at least one of the five tissues analyzed, with liver being the most drastically affected tissue. The new knowledge gained in this study could potentially be of value for considering direct modulation of gene expression by nutrient content in the diet.
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http://dx.doi.org/10.1007/s00335-017-9690-yDOI Listing
June 2017

FEELnc: a tool for long non-coding RNA annotation and its application to the dog transcriptome.

Nucleic Acids Res 2017 05;45(8):e57

Institut Génétique et Développement de Rennes, CNRS, UMR6290, University Rennes1, Rennes, Cedex 35043, France.

Whole transcriptome sequencing (RNA-seq) has become a standard for cataloguing and monitoring RNA populations. One of the main bottlenecks, however, is to correctly identify the different classes of RNAs among the plethora of reconstructed transcripts, particularly those that will be translated (mRNAs) from the class of long non-coding RNAs (lncRNAs). Here, we present FEELnc (FlExible Extraction of LncRNAs), an alignment-free program that accurately annotates lncRNAs based on a Random Forest model trained with general features such as multi k-mer frequencies and relaxed open reading frames. Benchmarking versus five state-of-the-art tools shows that FEELnc achieves similar or better classification performance on GENCODE and NONCODE data sets. The program also provides specific modules that enable the user to fine-tune classification accuracy, to formalize the annotation of lncRNA classes and to identify lncRNAs even in the absence of a training set of non-coding RNAs. We used FEELnc on a real data set comprising 20 canine RNA-seq samples produced by the European LUPA consortium to substantially expand the canine genome annotation to include 10 374 novel lncRNAs and 58 640 mRNA transcripts. FEELnc moves beyond conventional coding potential classifiers by providing a standardized and complete solution for annotating lncRNAs and is freely available at https://github.com/tderrien/FEELnc.
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http://dx.doi.org/10.1093/nar/gkw1306DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5416892PMC
May 2017

Transcriptional immune response in mesenteric lymph nodes in pigs with different levels of resistance to Ascaris suum.

Acta Parasitol 2017 Mar;62(1):141-153

A single nucleotide polymorphism on chromosome 4 (SNP TXNIP) has been reported to be associated with roundworm (Ascaris suum) burden in pigs. The objective of the present study was to analyse the immune response to A. suum mounted by pigs with genotype AA (n = 24) and AB (n = 23) at the TXNIP locus. The pigs were repeatedly infected with A. suum from eight weeks of age until necropsy eight weeks later. An uninfected control group (AA; n = 5 and AB; n = 5) was also included. At post mortem, we collected mesenteric lymph nodes and measured the expression of 28 selected immune-related genes. Recordings of worm burdens confirmed our previous results that pigs of the AA genotype were more resistant to infection than AB pigs. We estimated the genotype difference in relative expression levels in infected and uninfected animals. No significant change in expression levels between the two genotypes due to infection was observed for any of the genes, although IL-13 approached significance (P = 0.08; Punadjusted = 0.003). Furthermore, statistical analysis testing for the effect of infection separately in each genotype showed significant up-regulation of IL-13 (P<0.05) and CCL17 (P<0.05) following A. suum infection in the 'resistant' AA genotype and not in the 'susceptible' AB genotype. Pigs of genotype AB had higher expression of the high-affinity IgG receptor (FCGR1A) than AA pigs in both infected and non-infected animals (P = 1.85*10-11).
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http://dx.doi.org/10.1515/ap-2017-0017DOI Listing
March 2017

Joint Profiling of miRNAs and mRNAs Reveals miRNA Mediated Gene Regulation in the Göttingen Minipig Obesity Model.

PLoS One 2016 30;11(11):e0167285. Epub 2016 Nov 30.

Animal Genetics, Department of Veterinary Clinical and Animal Science, Faculty of Health Sciences, University of Copenhagen, Frederiksberg, Denmark.

Obesity and its comorbidities are an increasing challenge for both affected individuals and health care systems, worldwide. In obese individuals, perturbation of expression of both protein-coding genes and microRNAs (miRNA) are seen in obesity-relevant tissues (i.e. adipose tissue, liver and skeletal muscle). miRNAs are small non-coding RNA molecules which have important regulatory roles in a wide range of biological processes, including obesity. Rodents are widely used animal models for human diseases including obesity. However, not all research is applicable for human health or diseases. In contrast, pigs are emerging as an excellent animal model for obesity studies, due to their similarities in their metabolism, their digestive tract and their genetics, when compared to humans. The Göttingen minipig is a small sized easy-to-handle pig breed which has been extensively used for modeling human obesity, due to its capacity to develop severe obesity when fed ad libitum. The aim of this study was to identify differentially expressed of protein-coding genes and miRNAs in a Göttingen minipig obesity model. Liver, skeletal muscle and abdominal adipose tissue were sampled from 7 lean and 7 obese minipigs. Differential gene expression was investigated using high-throughput quantitative real-time PCR (qPCR) on 90 mRNAs and 72 miRNAs. The results revealed de-regulation of several obesity and inflammation-relevant protein-coding genes and miRNAs in all tissues examined. Many genes that are known to be de-regulated in obese humans were confirmed in the obese minipigs and several of these genes have target sites for miRNAs expressed in the opposing direction of the gene, confirming miRNA-mediated regulation in obesity. These results confirm the translational value of the pig for human obesity studies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0167285PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5130236PMC
July 2017

Identification of protein-damaging mutations in 10 swine taste receptors and 191 appetite-reward genes.

BMC Genomics 2016 08 26;17:685. Epub 2016 Aug 26.

Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, 08193 Cerdanyola del Valles, Catalonia, Spain.

Background: Taste receptors (TASRs) are essential for the body's recognition of chemical compounds. In the tongue, TASRs sense the sweet and umami and the toxin-related bitter taste thus promoting a particular eating behaviour. Moreover, their relevance in other organs is now becoming evident. In the intestine, they regulate nutrient absorption and gut motility. Upon ligand binding, TASRs activate the appetite-reward circuitry to signal the nervous system and keep body homeostasis. With the aim to identify genetic variation in the swine TASRs and in the genes from the appetite and the reward pathways, we have sequenced the exons of 201 TASRs and appetite-reward genes from 304 pigs belonging to ten breeds, wild boars and to two phenotypically extreme groups from a F2 resource with data on growth and fat deposition.

Results: We identified 2,766 coding variants 395 of which were predicted to have a strong impact on protein sequence and function. 334 variants were present in only one breed and at predicted alternative allele frequency (pAAF) ≥ 0.1. The Asian pigs and the wild boars showed the largest proportion of breed specific variants. We also compared the pAAF of the two F2 groups and found that variants in TAS2R39 and CD36 display significant differences suggesting that these genes could influence growth and fat deposition. We developed a 128-variant genotyping assay and confirmed 57 of these variants.

Conclusions: We have identified thousands of variants affecting TASRs as well as genes involved in the appetite and the reward mechanisms. Some of these genes have been already associated to taste preferences, appetite or behaviour in humans and mouse. We have also detected indications of a potential relationship of some of these genes with growth and fat deposition, which could have been caused by changes in taste preferences, appetite or reward and ultimately impact on food intake. A genotyping array with 57 variants in 31 of these genes is now available for genotyping and start elucidating the impact of genetic variation in these genes on pig biology and breeding.
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http://dx.doi.org/10.1186/s12864-016-2972-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5002119PMC
August 2016

Differential Analysis of the Nasal Microbiome of Pig Carriers or Non-Carriers of Staphylococcus aureus.

PLoS One 2016 10;11(8):e0160331. Epub 2016 Aug 10.

Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark.

Staphylococcus aureus is presently regarded as an emerging zoonotic agent due to the spread of specific methicillin-resistant S. aureus (MRSA) clones in pig farms. Studying the microbiota can be useful for the identification of bacteria that antagonize such opportunistic veterinary and zoonotic pathogen in animal carriers. The aim of this study was to determine whether the nasal microbiome of pig S. aureus carriers differs from that of non-carriers. The V3-V5 region of the 16S rRNA gene was sequenced from nasal swabs of 44 S. aureus carriers and 56 non-carriers using the 454 GS FLX titanium system. Carriers and non-carriers were selected on the basis of quantitative longitudinal data on S. aureus carriage in 600 pigs sampled at 20 Danish herds included in two previous studies in Denmark. Raw sequences were analysed with the BION meta package and the resulting abundance matrix was analysed using the DESeq2 package in R to identify operational taxonomic units (OTUs) with differential abundance between S. aureus carriers and non-carriers. Twenty OTUs were significantly associated to non-carriers, including species with known probiotic potential and antimicrobial effect such as lactic acid-producing isolates described among Leuconostoc spp. and some members of the Lachnospiraceae family, which is known for butyrate production. Further 5 OTUs were significantly associated to carriage, including known pathogenic bacteria such as Pasteurella multocida and Klebsiella spp. Our results show that the nasal microbiome of pigs that are not colonized with S. aureus harbours several species/taxa that are significantly less abundant in pig carriers, suggesting that the nasal microbiota may play a role in the individual predisposition to S. aureus nasal carriage in pigs. Further research is warranted to isolate these bacteria and assess their possible antagonistic effect on S. aureus for the pursuit of new strategies to control MRSA in pig farming.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0160331PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4980049PMC
August 2017

Hepatic expression of inflammatory genes and microRNAs in pigs with high "cholesteryl ester transfer protein" (CETP) activity.

Mamm Genome 2016 10 30;27(9-10):503-10. Epub 2016 May 30.

Section of Immunology and Vaccinology, Innate Immunology Group, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.

Human obesity and obesity-related diseases (ORD) are growing health problems worldwide and represent a major public health challenge. Most of these diseases are complex conditions, influenced by many genes (including microRNAs) and environmental factors. Many metabolic perturbations are associated with obesity; e.g., low levels of high-density lipoproteins (HDL) are high risk factors of cardiovascular events. A number of genetic, lifestyle, and environmental factors have been shown to contribute to the lowering of HDL-cholesterol. One of these factors is cholesteryl ester transfer protein (CETP) promoting the redistribution of cholesteryl esters, triglycerides, and phospholipids between plasma proteins. Moreover, obesity and ORD are often linked with chronic low-grade inflammation leading to insulin resistance and endothelial and microvascular dysfunctions. The aim of this study was to detect differences in the hepatic expression of genes involved in low-grade inflammation and of obesity- and cholesterol-related microRNAs in two mixed breed populations of pigs (Yorkshire-Göttingen minipig, YM and Duroc-Göttingen minipig, DM) including males and females, with extreme phenotypes for CETP activity levels (designated as CETP-high and CETP-low, respectively). Furthermore, breed and gender differences were also investigated. We found significant difference (P < 0.05) in hepatic expression levels of several mRNAs and microRNAs between the CETP-high and -low groups (C5, IL1RN, IL18, and miR-223-5p); between the two mixed breeds (IL1RAP and miR-140-5p); and between gender (APOA1, IL1RN, and FBLN1). Furthermore, when taking breed into account we show that the transcriptional levels of TNF, miR20a, miR33b, and miR130a differed between the two CETP groups. We conclude that increased CETP activity is accompanied by a modest differential hepatic expression of several microRNAs and inflammatory-related genes. Furthermore, our study demonstrates that when modeling the analysis of expression data, it is important to take gender- and breed-specific effects into account.
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http://dx.doi.org/10.1007/s00335-016-9649-4DOI Listing
October 2016

A large insertion in intron 2 of the TYRP1 gene associated with American Palomino phenotype in American mink.

Mamm Genome 2016 Apr 17;27(3-4):135-43. Epub 2016 Feb 17.

Department of Veterinary Clinical and Animal Sciences, Section of Genetics, Bioinformatics and Animal Breeding, Faculty of Health and Medical Sciences, University of Copenhagen, Groennegaardsvej 3, 1870, Frederiksberg C, Denmark.

A number of American mink phenotypes display a range of brownish colours. One of these phenotypes, namely American Palomino (b (P) b (P) ) (AP) has been found to be associated with the tyrosinase-related protein 1 (TYRP1) gene by genotyping microsatellite markers in one sire family. Trials for amplifying the genomic DNA and cDNA at the beginning of intron 2 of AP TYRP1 revealed the presence of a large insertion of approximately eight kb. The insertion most likely disrupts different elements necessary for the splicing of intron 2 of the TYRP1 gene. In AP RNAseq data indicate, however, the presence of the wild-type (wt) transcript at very low levels and Western blot reveals three products when using an antibody raised against middle part of the TYRP1 protein. One individual from another brown mink phenotype-commercially named Dawn-was also investigated at the molecular level by long-range PCR and the same size insertion appears to be present. By this we suggest that certain modifiers of TYRP1 would induce different brown colour degradation, which results in at least two different phases of brown.
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http://dx.doi.org/10.1007/s00335-016-9620-4DOI Listing
April 2016

Altered Methylation Profile of Lymphocytes Is Concordant with Perturbation of Lipids Metabolism and Inflammatory Response in Obesity.

J Diabetes Res 2016 21;2016:8539057. Epub 2015 Dec 21.

Inflammation and Infection Research, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia.

Obesity is associated with immunological perturbations that contribute to insulin resistance. Epigenetic mechanisms can control immune functions and have been linked to metabolic complications, although their contribution to insulin resistance still remains unclear. In this study, we investigated the link between metabolic dysfunction and immune alterations with the epigenetic signature in leukocytes in a porcine model of obesity. Global DNA methylation of circulating leukocytes, adipose tissue leukocyte trafficking, and macrophage polarisation were established by flow cytometry. Adipose tissue inflammation and metabolic function were further characterised by quantification of metabolites and expression levels of genes associated with obesity and inflammation. Here we show that obese pigs showed bigger visceral fat pads, higher levels of circulating LDL cholesterol, and impaired glucose tolerance. These changes coincided with impaired metabolism, sustained macrophages infiltration, and increased inflammation in the adipose tissue. Those immune alterations were linked to global DNA hypermethylation in both B-cells and T-cells. Our results provide novel insight into the possible contribution of immune cell epigenetics into the immunological disturbances observed in obesity. The dramatic changes in the transcriptomic and epigenetic signature of circulating lymphocytes reinforce the concept that epigenetic processes participate in the increased immune cell activation and impaired metabolic functions in obesity.
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http://dx.doi.org/10.1155/2016/8539057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4698937PMC
October 2016

Physical training and weight loss in dogs lead to transcriptional changes in genes involved in the glucose-transport pathway in muscle and adipose tissues.

Vet J 2016 Feb 10;208:22-7. Epub 2015 Nov 10.

Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. Electronic address:

Obesity is a worldwide problem in humans and domestic animals. Interventions, including a combination of dietary management and exercise, have proven to be effective for inducing weight loss in humans. In companion animals, the role of exercise in the management of obesity has received relatively little attention. The aim of the present study was to investigate changes in the transcriptome of key energy metabolism genes in muscle and adipose tissues in response to diet-induced weight loss alone, or combined with exercise in dogs. Overweight pet dogs were enrolled on a weight loss programme, based on calorie restriction and physical training (FD group, n = 5) or calorie restriction alone (DO group, n = 7). mRNA expression of 12 genes and six microRNAs were investigated using quantitative real-time PCR (qPCR). In the FD group, FOXO1 and RAC1 were expressed at lower levels in adipose tissue, whereas ESRRA and AKT2 were more highly expressed in muscle, when compared with the DO group. Comparing expression before and after the intervention, in the DO group, nine genes and three microRNAs showed significant altered expression in adipose tissue (PPARG, ADIPOQ and FOXO1; P < 0.001) and seven genes and two microRNAs were significantly downregulated (NRF2, RAC1, ESRRA, AKT2, PGC1a and mir-23; P < 0.001) in muscle. Thus, calorie restriction causes regulation of several metabolic genes in both tissues. The mild exercise, incorporated into this study design, was sufficient to elicit transcriptional changes in adipose and muscle tissues, suggesting a positive effect on glucose metabolism. The study findings support inclusion of exercise in management of canine obesity.
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http://dx.doi.org/10.1016/j.tvjl.2015.11.002DOI Listing
February 2016