Pilar Zaragoza

A medium-density genetic linkage map of the bovine genome

A cattle genetic linkage map was constructed which covers more than 95 percent of the bovine genome at medium density. Seven hundred and forty six DNA polymorphisms were genotyped in cattle families which comprise 347 individuals in full sibling pedigrees. Seven hundred and three of the loci are linked to at least one other locus. All linkage groups are assigned to chromosomes, and all are orientated with regards to the centromere. There is little overall difference in the lengths of the bull and cow linkage maps although there are individual differences between maps of chromosomes. One hundred and sixty polymorphisms are in or near genes, and the resultant genome-wide comparative analyses indicate that while there is greater conservation of synteny between cattle and humans compared with mice, the conservation of gene order between cattle and humans is much less than would be expected from the conservation of synteny. This map provides a basis for high-resolution mapping of the bovine genome with physical resources such as Yeast and Bacterial Artificial Chromosomes as well as providing the underpinning for the interpolation of information from the Human Genome Project.USDA-MARC family and data for validating this family. P. Creighton, C. Skidmore, T. Holm, and A. Georgoudis provided some validation data for the BOVMAP families. R. Fries, S. Johnson, S. Solinas Toldo, and A. Mezzelani kindly made some of their FISH assignments available before publication. We wish to thank all those researchers who kindly sent us probes and DNA primers.

Effect of transport time on welfare and meat quality in pigs.

The purpose of this study was to determine the effects of transport duration on some welfare and meat quality parameters. For the study 144 pigs were used. One group of 72 animals was subjected to 15 min and the others to 3 h transport time. Blood from all animals was analysed in order to detect stress-susceptible pigs and assess pre-slaughter stress. Meat quality parameters were analysed from Longissimus thoracis and Semimembranosus muscles. It was concluded that under normal Spanish commercial conditions, pigs subjected to short transport showed a more intense stress response and poorer meat quality than pigs subjected to moderately long transport when they were immediately slaughtered on arrival at the slaughterhouse. Transport of 3 h might have allowed the animals to adapt to transport conditions and then could act as a resting period like a lairage time. The effect of transport time on welfare and meat quality parameters was more important than genotype and sex. Nevertheless, from the point of view of blood enzyme activities, genetically stress susceptible females transported for 3 h were more sensitive to muscle damage.

Immunophenotype and gene expression profiles of cell surface markers of mesenchymal stem cells derived from equine bone marrow and adipose tissue.

Bone marrow and adipose tissue are the two main sources of mesenchymal stem cell (MSC). The aim of this work was to analyse the immunophenotype of 7 surface markers and the expression of a panel of 13 genes coding for cell surface markers in equine bone marrow and adipose tissue-derived MSCs obtained from 9 horses at third passage. The tri-lineage differentiation was confirmed by specific staining. Equine MSCs from both sources were positive for the MSC markers CD29 and CD90, while were negative for CD44, CD73, CD105, CD45 and CD34. The gene expression of these molecules was also evaluated by reverse transcriptase real-time quantitative PCR along with the expression of 5 other MSC markers. Both populations of cells expressed CD13, CD29, CD44, CD49d, CD73, CD90, CD105, CD106, CD146 and CD166 transcripts. Significant differences in gene expression levels between BM- and AT-MSCs were observed for CD44, CD90, CD29 and CD34. Both cell types were negative for CD45 and CD31. The surface antigens tested revealed a similar phenotypic profile between horse and human MSCs, although specific differences in some surface antigens were noticed.

Optimal methods to characterize the G93A mouse model of ALS

In the present study, we used the SOD1 (G93A) mutant transgenic mice as a model of amyotrophic lateral sclerosis (ALS). This model is widely used as a laboratory tool to study experimental treatments in vivo for ALS to investigate new therapeutic strategies for this neurodegenerative disease. Such studies require the objective quantification of different parameters while mice develop the disease. We have applied a battery of different and specific tests: scoring of motor deficits by a trained observer, weighing, survival measure, hanging wire test, rotarod task and electromyography, most of them commonly used to evaluate G93A animals. We have critically compared these methods, showing the significant influence of gender on the onset of symptoms, and the optimal moment to apply each test. These results should be taken into account in future therapeutic assays on this ALS model.

MicroRNA-206: A Potential Circulating Biomarker Candidate for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a lethal motor neuron disease that progressively debilitates neuronal cells that control voluntary muscle activity. Biomarkers are urgently needed to facilitate ALS diagnosis and prognosis, and as indicators of therapeutic response in clinical trials. microRNAs (miRNAs), small posttranscriptional modifiers of gene expression, are frequently altered in disease conditions. Besides their important regulatory role in variety of biological processes, miRNAs can also be released into the circulation by pathologically affected tissues and display remarkable stability in body fluids. In a mouse model of ALS that expresses mutated human superoxide dismutase 1 (SOD1-G93A) skeletal muscle is one of the tissues affected early by mutant SOD1 toxicity. To find biomarkers for ALS, we studied miRNA alterations from skeletal muscle and plasma of SOD1-G93A mice, and subsequently tested the levels of the affected miRNAs in the serum from human ALS patients. Fast-twitch and slow-twitch muscles from symptomatic SOD1-G93A mice (age 90 days) and their control littermates were first studied using miRNA microarrays and then evaluated with quantitative PCR from five age groups from neonatal to the terminal disease stage (10–120 days). Among those miRNA changed in various age/gender/muscle groups (miR-206, -1, -133a, -133b, -145, -21, -24), miR-206 was the only one consistently altered during the course of the disease pathology. In both sexes, mature miR-206 was increased in fast-twitch muscles preferably affected in the SOD1-G93A model, with highest expression towards the most severely affected animals. Importantly, miR-206 was also increased in the circulation of symptomatic animals and in a group of 12 definite ALS patients tested. We conclude that miR-206 is elevated in the circulation of symptomatic SOD1-G93A mice and possibly in human ALS patients. Although larger scale studies on ALS patients are warranted, miR-206 is a promising candidate biomarker for this motor neuron disease.

Geographic distribution of haplotype diversity at the bovine casein locus

The genetic diversity of the casein locus in cattle was studied on the basis of haplotype analysis. Consideration of recently described genetic variants of the casein genes which to date have not been the subject of diversity studies, allowed the identification of new haplotypes. Genotyping of 30 cattle breeds from four continents revealed a geographically associated distribution of haplotypes, mainly defined by frequencies of alleles at CSN1S1 and CSN3. The genetic diversity within taurine breeds in Europe was found to decrease significantly from the south to the north and from the east to the west. Such geographic patterns of cattle genetic variation at the casein locus may be a result of the domestication process of modern cattle as well as geographically differentiated natural or artificial selection. The comparison of African Bos taurus and Bos indicus breeds allowed the identification of several Bos indicus specific haplotypes (CSN1S1*C-CSN2*A2-CSN3*AI/CSN3*H) that are not found in pure taurine breeds. The occurrence of such haplotypes in southern European breeds also suggests that an introgression of indicine genes into taurine breeds could have contributed to the distribution of the genetic variation observed.

Comparative study of equine bone marrow and adipose tissue‐derived mesenchymal stromal cells

REASONS FOR PERFORMING STUDY Mesenchymal stromal cells (MSCs) represent an attractive source for regenerative medicine. However, prior to their application, fundamental questions regarding molecular characterisation, growth and differentiation of MSCs must be resolved. OBJECTIVES To compare and better understand the behaviour of equine MSCs obtained from bone marrow (BM) and adipose tissue (AT) in culture. METHODS Five horses were included in this study. Proliferation rate was measured using MTT assay and cell viability; apoptosis, necrosis and late apoptosis and necrosis were evaluated by flow cytometry. The mRNA expression levels of 7 surface marker genes were quantified using RT-qPCR and CD90 was also analysed by flow cytometry. Differentiation was evaluated using specific staining, measurement of alkaline phosphatase activity and analysis of the mRNA expression. RESULTS High interindividual differences were observed in proliferation in both cell types, particularly during the final days. Statistically significant differences in viability and early apoptosis of cultured AT- and BM-MSCs were found. The highest values of early apoptosis were observed during the first days of culture, while the highest percentage of necrosis and late apoptosis and lowest viability was observed in the last days. Surface marker expression pattern observed is in accordance to other studies in horse and other species. Osteogenic differentiation was evident after 7 days, with an increasing of ALP activity and mRNA expression of osteogenic markers. Adipogenic differentiation was achieved in BM-MSCs from 2 donors with one of the 16 media tested. Chondrogenic differentiation was also observed. CONCLUSIONS Proliferation ability is different in AT-MSCs and BM-MSCs. Differences in viability and early apoptosis were observed between both sources and CD34 was only found in AT-MSCs. Differences in their osteogenic and adipogenic potential were detected by staining and quantification of specific tissue markers. POTENTIAL RELEVANCE To provide data to better understand AT-MSCs and BM-MSCs behaviour in vitro.

Fragment C of tetanus toxin, more than a carrier. Novel perspectives in non-viral ALS gene therapy

The non-toxic carboxy-terminal fragment of tetanus toxin heavy chain (TTC) has been implicated in the activation of cascades responsible for trophic actions and neuroprotection by inhibition of apoptosis. Previous in vitro studies have described signalling pathways that underlie the administration of TTC to neurons. We investigated whether these properties were maintained in a mouse model of neurodegenerative disease. Naked DNA encoding for TTC was injected intramuscularly and neuromuscular function and clinical behaviour were monitored until endstage in the transgenic SOD1G93A mouse model that expresses a mutant variant of human superoxide dismutase 1 (SOD1). Our results indicate that TTC treatment ameliorated the decline of hindlimb muscle innervation, significantly delayed the onset of symptoms and functional deficits, improved spinal motor neuron survival, and prolonged lifespan. Furthermore, we found that caspase-1 and caspase-3 proapoptotic genes were down-regulated in the spinal cord of treated mice. Western blot analysis showed that the active form of caspase-3 was also down-regulated after TTC treatment and survival signals, such as the significant phosphorylation of serine/threonine protein kinase Akt, were also detected. These results suggest that fragment C of tetanus toxin, TTC, provides a potential therapy for neurodegenerative diseases.

Isolation and characterization of ovine mesenchymal stem cells derived from peripheral blood

BackgroundMesenchymal stem cells (MSCs) are multipotent stem cells with capacity to differentiate into several mesenchymal lineages. This quality makes MSCs good candidates for use in cell therapy. MSCs can be isolated from a variety of tissues including bone marrow and adipose tissue, which are the most common sources of these cells. However, MSCs can also be isolated from peripheral blood. Sheep has been proposed as an ideal model for biomedical studies including those of orthopaedics and transmissible spongiform encephalopathies (TSEs). The aim of this work was to advance these studies by investigating the possibility of MSC isolation from ovine peripheral blood (oPB-MSCs) and by subsequently characterizing there in vitro properties.ResultsPlastic-adherent fibroblast-like cells were obtained from the mononuclear fraction of blood samples. These cells were analysed for their proliferative and differentiation potential into adipocytes, osteoblasts and chondrocytes, as well as for the gene expression of cell surface markers. The isolated cells expressed transcripts for markers CD29, CD73 and CD90, but failed to express the haematopoietic marker CD45 and expressed only low levels of CD105. The expression of CD34 was variable. The differentiation potential of this cell population was evaluated using specific differentiation media. Although the ability of the cultures derived from different animals to differentiate into adipocytes, osteoblasts and chondrocytes was heterogeneous, we confirmed this feature using specific staining and analysing the gene expression of differentiation markers. Finally, we tested the ability of oPB-MSCs to transdifferentiate into neuronal-like cells. Morphological changes were observed after 24-hour culture in neurogenic media, and the transcript levels of the neurogenic markers increased during the prolonged induction period. Moreover, oPB-MSCs expressed the cellular prion protein gene (PRNP), which was up-regulated during neurogenesis.ConclusionsThis study describes for the first time the isolation and characterization of oPB-MSCs. Albeit some variability was observed between animals, these cells retained their capacity to differentiate into mesenchymal lineages and to transdifferentiate into neuron-like cells in vitro. Therefore, oPB-MSCs could serve as a valuable tool for biomedical research in fields including orthopaedics or prion diseases.

Genomic structure and alternative transcript of bovine fatty acid synthase gene (FASN): comparative analysis of the FASN gene between monogastric and ruminant species

Fatty acid synthesis differs considerably between monogastric and ruminant species. Fatty acid synthase (FASN) plays a central role in de novo lipogenesis in mammals. FASN has seven active sites which help to catalyse all the reaction steps in the conversion of acetyl-CoA and malonyl-CoA to palmitate. In this work, the bovine fatty acid synthase gene (FASN) was cloned, characterized and compared to the human and rat orthologs. Comparative analysis reveals evolutionarily conserved exon regions and gene flanking sequences. Analysis of the DNA sequence in the 5′ flanking region of the FASN bovine gene revealed a potential TATA box, CAAT box and 5 Sp1 binding sites located in a CpG island. RT-PCR and Western blot analysis showed that FASN expression was higher in brain, testis and adipose tissue than in liver and heart. The longer form of the FASN cDNA includes a 7,542-bp sequence which encodes a protein with 2,513 amino acids. An alternative transcript was discovered in bovine and ovine tissues devoid of part of exon 9. The removal of part of exon 9 by post-transcriptional splicing causes a frameshift in the open reading frame and results in a premature termination codon. We hypothesize that in ruminants, FASN may be regulated by the ratio between the two transcripts. The small transcript is mostly produced in tissues with low fatty acid synthesis.