Selection of ovine housekeeping genes for normalisation by real-time RT-PCR; analysis of PrP gene expression and genetic susceptibility to scrapie

Betaine Induces Apoptosis and Inhibits Invasion in OSCC Cell Lines

Betaine, known as trimethylglycine, is a non-toxic natural substance reported to affect cancer cell responses. This study delves into the impact of betaine on the survival, proliferation, and invasion of oral squamous cell carcinoma (OSCC) cells in vitro. Human OSCC cells (HSC-4 and HSC-7) were subjected to varying concentrations of betaine, and their viability and proliferation were assessed through colourimetric MTT and colony-forming unit assays. Cell cycle progression and cell apoptosis were also investigated using flow cytometry, while cell migration and invasion were examined using a transwell migration assay, and the mRNA expression was evaluated by a quantitative polymerase chain reaction. Finally, proteomic analysis was conducted through liquid chromatography-tandem mass spectrometry on the extracted protein component of the cells. Results indicate that betaine effectively suppressed OSCC proliferation and colony formation. It triggered early apoptosis without disrupting cell cycle progression, reduced cell migration, and inhibited invasion. Betaine exposure led to significantly decreased mRNA levels of MMP1, MMP2, and MMP9 while downregulating FN1, a gene linked to epithelial-to-mesenchymal transition. Proteomic analysis revealed 9240 differentially expressed up/downregulated proteins in cells treated with betaine. The significantly upregulated proteins were associated with ATP-binding cassette (ABC) transporters, while the down-regulated proteins were associated with G protein-coupled receptors (GPCR) ligand binding. In conclusion, betaine exhibits potent anti-cancer properties by attenuating OSCC cell proliferation and mitigating invasion. Exploring this natural product as an adjunct for managing oral squamous cell carcinoma shows promise, although further investigations are needed to fully elucidate its functionality.

Assessment of reference genes for qRT-PCR normalization to elucidate host response to African swine fever infection

Viral infection disrupts the normal regulation of the host gene's expression. In order to normalise the expression of dysregulated host genes upon virus infection, analysis of stable reference housekeeping genes using quantitative real-time-PCR (qRT-PCR) is necessary. In the present study, healthy and African swine fever virus (ASFV) infected porcine tissues were assessed for the expression stability of five widely used housekeeping genes (HPRT1, B2M, 18 S rRNA, PGK1 and H3F3A) as reference genes using standard algorithm. Total RNA from each tissue sample (lymph node, spleen, kidney, heart and liver) from healthy and ASFV-infected pigs was extracted and subsequently cDNA was synthesized, and subjected to qRT-PCR. Stability analysis of reference genes expression was performed using the Comparative delta CT, geNorm, BestKeeper and NormFinder algorithm available at RefFinder for the different groups. Direct Cycle threshold (CT) values of samples were used as an input for the web-based tool RefFinder. HPRT1 in spleen, 18 S rRNA in liver and kidney and H3F3A in heart and lymph nodes were found to be stable in the individual healthy tissue group (group A). The majority of the ASFV-infected organs (liver, kidney, heart, lymph node) exhibited H3F3A as stable reference gene with the exception of the ASFV-infected spleen, where HPRT1 was found to be the stable gene (group B). HPRT1 was found to be stable in all combinations of all CT values of both healthy and ASFV-infected porcine tissues (group C). Of five different reference genes investigated for their stability in qPCR analysis, the present study revealed that the 18 S rRNA, H3F3A and HPRT1 genes were optimal reference genes in healthy and ASFV-infected different porcine tissue samples. The study revealed the stable reference genes found in healthy as well as ASF-infected pigs and these reference genes identified through this study will form the baseline data which will be very useful in future investigations on gene expression in ASFV-infected pigs.

Skeletal muscle transcriptomics of sheep acclimated to cold desert and tropical regions identifies genes and pathways accentuating their diversity

The current study attempts to investigate the differences in gene expression in longissimus thoracis muscles between sheep breeds acclimated to diverse environments. Changthangi sheep inhabits the cold arid plateau of Ladakh, at an altitude above 3000 m with prevalence of rarefied atmosphere. Muzzafarnagri sheep, on the other hand is found in the sub-tropical hot and humid plains at an altitude of about 250 m. Comparative transcriptomics was used to provide a molecular perspective of the differential adaptation of the two breeds. RNA sequencing data was generated from four biological replicates of the longissimus thoracis muscles from both breeds. The common genes expressed in both breeds were involved in muscle contraction and muscle fibre organization. The most significant pathways enriched in Changthangi muscles were glycogen metabolism, reduction of cytosolic Ca++ levels and NFE2L2 regulating anti-oxidant, while those in Muzzafarnagri were extracellular matrix organization and collagen formation. The hub genes identified in Changthangi were involved in hematopoiesis and HIF signaling pathway, suggesting the molecular acclimatization of Changthangi to the high altitude cold desert of Ladakh. The nodal genes discovered in Muzzafarnagri sheep were associated with the extracellular matrix which accentuates its significance in the development, growth and repair of muscles. The observed transcriptomic differences underscore the morphological and adaptive disparity between the two breeds. The candidate genes and pathways identified in this study will form the basis for future research on adaptation to high altitude and body size in small ruminants.

Evaluation of reference genes for gene expression analysis by real-time quantitative PCR (qPCR) in different tissues from mice infected by Ascaris suum

Human ascariasis is the most prevalent helminth infection, affecting 445 million people worldwide. To better understand the impact of the immune system on the pathophysiology of individuals infected with Ascaris suum, mice have been used as experimental models. The RT-qPCR technique is a critical auxiliary tool of investigation used to quantify mRNA levels. However, proper normalization using reference genes is essential to ensure reliable outcomes to avoid analytical errors and false results. Despite the importance of reference genes for experimental A. suum infection studies, no specific reference genes have been identified yet. Therefore, we conducted a study to assess five potential reference genes (GAPDH, 18s, ACTB, B2M, and HPRT1) in different tissues (liver, lungs, small and large intestines) affected by A. suum larval migration in C57BL/6j mice. Tissue collection was carried out to analyze parasite burden and confirm the presence of larvae during the peak of migration in each tissue. Upon confirmation, we analyzed different genes in the tissues and found no common gene with stable expression. Our results highlight the importance of analyzing different genes and using different software programs to ensure reliable relative expression results. Based on our findings, B2M was ranked as the ideal reference gene for the liver, while 18S was the most stable gene in the lung and small intestine. ACTB, or a combination of ACTB with GAPDH, was deemed suitable as reference genes for the large intestine due to their stable expression and less variation between the control and infected groups. To further demonstrate the impact of using different reference genes, we normalized the expression of a chemokine gene (CXCL9) in all tissues. Significant differences in CXCL9 expression levels were observed between different groups in all tissues except for the large intestine. This underscores the importance of selecting appropriate reference genes to avoid overestimating target gene expression levels and encountering normalization-related issues that can lead to false results. In conclusion, our study highlights the significance of using reliable reference genes for accurate RT-qPCR analysis, especially in the context of A. suum infection studies in different tissues. Proper normalization is crucial to ensure the validity of gene expression data and avoid potential pitfalls in interpreting results.

Identification and validation of stable reference genes for expression profiling of target genes in diverse ovine tissues

Quantitative PCR (qPCR) is a widely-used technique for quantifying the expression of target genes across various tissues, as well as under different pathological and physiological conditions. One of the challenges associated with this method is the need to identify optimal reference genes (RGs) that maintain consistent expression levels under diverse experimental settings, thereby ensuring accurate biological interpretation. In this study, we conducted a thorough analysis of 18 candidate RGs (ACTB, BACH1, B2M, GAPDH, HMBS, HPRT1, PGK1, PPIA, PPIB, RPLP0, RPL19, RPS9, RPS15, RPS28, SDHA, TBP, UXT, and YWHAZ) across 10 ovine tissues (muscle, skin, kidney, liver, intestine, rumen, lung, testis, heart, and spleen) obtained from five individual sheep. We aimed to identify genes with stable expression across these tissues. A literature-based survey helped us shortlist candidate genes representing various functional classes from multiple livestock species. We employed four algorithms: geNorm, NormFinder, BestKeeper, and Delta Ct (ΔCt), to rank these genes based on their stability. A consistent trend in the rankings was observed across these different algorithms. RefFinder was then used for a comprehensive ranking, integrating the outputs from the various methods. ACTB, PPIB, BACH1, and B2M emerged as the most stable RGs, while RPS9, RPS15, and PGK1 displayed variable expression. We validated our findings through qPCR analysis of four target genes (ACTN2, CRYAB, DLK1, and TRIM54) in the skin samples from two different sheep breeds. Based on these results, we recommend ACTB, PPIB, BACH1, and B2M as reliable internal control genes for qPCR experiments involving diverse ovine tissues.

Impact of carob (Ceratonia siliqua L.) pulp inclusion and warm season on gastrointestinal morphological parameters, immune-redox defences and coccidiosis in concentrate-fed light lambs

This study aimed to evaluate the effects of dietary carob (Ceratonia siliqua L.) pulp and warm season on gastrointestinal morphological parameters, immune-redox defences and coccidiosis in concentrate-fed light lambs. Weaned lambs were assigned to one of three concentrate-based diets: C0 (without carob pulp), C15 (150 g/kg of carob pulp) and C30 (300 g/kg of carob pulp) from 40 to 80 days of age in two consecutive cold and warm batches. Blood samples were collected at Day 80 to determine the metabolic status. Rectal faeces were sampled at Days 50, 65 and 80 to determine consistency and oocyst count per gram. Inclusion of carob pulp in lamb diets did not affect lamb growth but reduced coccidia oocyst excretion, improved faecal consistency and gastrointestinal morphological parameters, enhancing the ruminal thickness of the papilla living strata and reducing the darkness of the epithelium colour. Moreover, carob condensed tannins in the lambs' diet enhanced the expression of antioxidant SOD2 in rumen, while down-regulated NRF2, SOD1, CAT and PPARG in ileum. There was no interaction between the treatments and season in the evaluated variables. Lambs from the warm season exhibited reduced growth performance, altered ruminal epithelium, lower circulating iron levels, increased protein concentrations and higher coccidiosis susceptibility. In addition, regulatory immune and antioxidant mechanisms to counterbalance reactive oxygen species production in gastrointestinal tissues were evident. Dietary inclusion of carob pulp (150 and 300 g/kg) in lamb diets improved gastrointestinal health and homeostasis but did not ameliorate the deleterious effects of warm season.

Analysis of the stability of the reference genes GAPDH, SDHA and RPL-19 in sheep from a semi-arid region infected by gastrointestinal nematodes

Analyzing the stability of reference genes already described as universal is an important methodology to lead gene expression analysis because different studies have shown that the expression of universal reference genes may vary between experimental treatments. In this sense, the glyceraldehyde 3-phosphate dehydrogenase (GAPDH), Succinate dehydrogenase complex subunit A (SDHA) and Ribosomal Protein L-19 (RPL-19) reference genes (already described in other studies with sheep from different regions, breeds and infectious agents or in organisms evolutionarily close to sheep) were investigated in the abomasum, small and large intestines of resistant and susceptible crossbred sheep groups to gastrointestinal nematode infections in the Semi-arid region in Northeast of Brazil. The animals were naturally infected to determine the resistance or susceptibility status by counting eggs per gram (EPG) of feces from the gastrointestinal tract after 33 weeks of observations of infection evolution. Relative gene expression was performed by RT-qPCR methodology using Sybr green and relative gene expression stability was tested by different software programs such as REST, BestKeeper, geNorm and Normfinder. Our results showed the susceptible animals had increase in egg counts per gram of feces than resistant animals (p < 0.001), and both groups showed a mixed infection by nematodes of the genus Haemonchus, Trichostrongylus, Oesophagostomum and Trichuris. Furthermore, we show the importance of analyzing different genes in different software programs and the importance to choose ideal reference genes. In this sense, GAPDH was the most stable gene in the abomasum, whereas SDHA was the most stable in the small and large intestines. In addition, we discuss about variables which can interfere in relative expression such as breed, species, climate and tissue. However, utilizing other reference genes already described in other studies with the same and different variables should be performed.

Selection and validation of suitable reference gene for qPCR gene expression analysis in lamb testis cells under Sheep pox virus infection

Virus infection alters host gene expression, therefore ideal and stable reference housekeeping genes are required to normalise the expression of other expressed host genes in quantitative real-time PCR (qRT-PCR). The suitable reference gene may vary in response to different viral infections in different hosts or cells. In the present study, we cultured primary lamb testis cells (LTC) and assessed the expression stability of seven widely used housekeeping genes (B2M, HMBS, HPRT1, HSP-90, POLR2A, 18s_RNA, GAPDH) as reference genes in Sheeppox virus (SPPV) infected and control (uninfected-0h) LTC at 0.5h, 4.0h, 8.0h, and 12.0h post-infection) using NormFinder, Bestkeeper, geNorm, and the comparative ΔCT method in RefFinder based on their expression levels. Analysis revealed that HSP90, 18s_RNA, HPRT, POLR2A, and B2M were the most stable genes from the panel in the individual analysis group in 0h, 0.5h, 4.0h, 8.0h, and 12.0h, respectively. Furthermore, B2M was shown to be the most stable reference gene in the combined control with the respective and overall infected groups, except the control group of 4.0hpi of SPPV infection. In this study, we selected the most suitable reference genes in LTC for particular time points of SPPV infection. The identified most suitable housekeeping gene can be used during normalization of expression of other targeted genes at aspecific time point of SPPV infection.

Distinctive Toll-like Receptors Gene Expression and Glial Response in Different Brain Regions of Natural Scrapie

Prion diseases are chronic and fatal neurodegenerative diseases characterized by the accumulation of disease-specific prion protein (PrP^Sc), spongiform changes, neuronal loss, and gliosis. Growing evidence shows that the neuroinflammatory response is a key component of prion diseases and contributes to neurodegeneration. Toll-like receptors (TLRs) have been proposed as important mediators of innate immune responses triggered in the central nervous system in other human neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. However, little is known about the role of TLRs in prion diseases, and their involvement in the neuropathology of natural scrapie has not been studied. We assessed the gene expression of ovine TLRs in four anatomically distinct brain regions in natural scrapie-infected sheep and evaluated the possible correlations between gene expression and the pathological hallmarks of prion disease. We observed significant changes in TLR expression in scrapie-infected sheep that correlate with the degree of spongiosis, PrP^Sc deposition, and gliosis in each of the regions studied. Remarkably, TLR4 was the only gene upregulated in all regions, regardless of the severity of neuropathology. In the hippocampus, we observed milder neuropathology associated with a distinct TLR gene expression profile and the presence of a peculiar microglial morphology, called rod microglia, described here for the first time in the brain of scrapie-infected sheep. The concurrence of these features suggests partial neuroprotection of the hippocampus. Finally, a comparison of the findings in naturallyinfected sheep versus an ovinized mouse model (tg338 mice) revealed distinct patterns of TLRgene expression.

Plane of nutrition and FSH-induced superovulation affect the expression of steroid hormone receptors and growth factors in caruncular tissue of non-pregnant sheep

Implantation is a critical step in the establishment of pregnancy and an important part of embryo-maternal contact. Uterine receptivity can be affected by changes in body condition and the maternal endocrine milieu, including those caused by the use of exogenous gonadotropins in controlled ovarian hyperstimulation to induce the development of multiple follicles. This study demonstrates the effects of FSH-mediated ovarian hyperstimulation on the caruncles of ewes under various feeding regimes. Sheep were classified into 3 categories: control fed (CF), overfed (OF), or underfed (UF). In each group, animals were superovulated with FSH or injected with a saline solution (non-treated control). Uterine caruncles were collected at the early (d 5) and mid-luteal phase (d 10) of the estrous cycle. The transcript levels of steroid hormone receptors (ESR1, ESR2, PGR) and growth factors (IGF1, IGF2, VEGFA) were investigated and their expression localized by immunohistochemical staining. As for the main findings, day of the estrous cycle affected expression of ESR1, IGF1 and IGF2, but not of ESR2, PGR and VEGFA; both feeding and superovulation had modulatory effects, with feeding (UF/OF) stimulating expression of all genes studied, and superovulation altering expression of some genes, eg IGF1, PGR and ESR1 and ESR2, in CF animals. Similarly, feeding (UF/OF) altered responsiveness to superovulation for PGR on d 5 and ESR1/ESR2 on d 5 and/or 10. Our data emphasize possible effects of dietary and/or hormonal stimuli on uterine physiology, which may affect pregnancy outcomes by disrupting uterine functionality.

PPP2R2A affects embryonic implantation by regulating the proliferation and apoptosis of Hu sheep endometrial stromal cells

Embryonic implantation is a complex reproductive physiological process in mammals. Although several endometrial proteins affecting embryonic implantation have been reported in the past, there are still potential endometrial proteins that have been neglected, and their specific regulatory mechanisms are unclear. This study demonstrated that protein phosphatase 2A regulatory subunit B55α (PPP2R2A) served as a novel regulator in medication of sheep embryonic implantation in vitro. Our results showed that sheep PPP2R2A encoded 447 amino acids and shared 91.74%-92.36% amino acid sequences with its orthologs compared with other species. Meanwhile, PPP2R2A was widely expressed in sheep uterine tissues, and it could regulate the expression levels of key regulators of embryonic implantation in endometrial stromal cells (ESCs). Knockdown of PPP2R2A significantly inhibited cell proliferation by blocking cell cycle transfer G0/G1 into S phase accompanied by downregulation of CDK2, CDK4, CCND1, CCNE1 and upregulation of P21. In contrast to PPP2R2A overexpression, PPP2R2A interference greatly promoted cell apoptosis and the expression of BAX, CASP3, CASP9 and BAX/BCL-2. Taken together, these results suggest that PPP2R2A, as a novel regulatory factor, affects embryonic implantation via regulating the proliferation and apoptosis of Hu sheep ESCs in vitro.

Expression patterns of major genes in fatty acid synthesis, inflammation, oxidative stress pathways from colostrum to milk in Damascus goats

The molecular regulation of milk secretion and quality in the transition period from colostrum to milk in goats is largely unknown. In the present study, mammary gland secretion of goats was collected in 0th, 4th, 7th, 14th and 28th days after parturition. In addition to composition and fatty acid profile of colostrum or milk, FASN, SCD, ACACA, COX-2, NRF2, TLR2, NF-kB, LTF and PTX3 genes expression patterns were determined from milk somatic cells. While somatic cell count (SCC), malondialdehyde (MDA), fat, fat-free dry matter, protein and lactose were highest as expression levels of the oxidative and inflammatory genes, freezing point and electrical conductivity were lowest in colostrum. With the continuation of lactation, most of the fatty acids, n3 ratio, and odour index increased but C14:0 and C16:0 decreased. While FASN was upregulated almost threefolds in 14th day, ACACA was upregulated more than fivefolds in 7th and 14th days. Separately, the major genes in fatty acid synthesis, inflammation and oxidative stress were significantly associated with each other due to being positively correlated. MDA was positively correlated with SCC and some of the genes related inflammation and oxidative stress. Furthermore, significant negative correlations were determined between SCC and fatty acid synthesis related genes. With this study, transition period of mammary secretion was particularly clarified at the molecular levels in Damascus goats.

Expression of cytokine genes at tick attachment and control sites of Namaqua Afrikaner, Dorper and South African Mutton Merino sheep

Cytokines are immune response components important in innate immunity and inflammatory response. They are harnessed as part of local immunological responses by animals to combat local infections and/or infestations. This study investigated expression of four selected cytokine genes, namely, interleukin 1 beta (IL-1β), chemokine C-C ligand 2 (CCL2), chemokine C-C ligand 26 (CCL26) and interleukin 8 (IL-8), at tick attachment and control sites in a South African indigenous sheep breed the Namaqua Afrikaner (NA) and two commercial breeds, the Dorper and South African Mutton Merino (SAMM). The NA was previously shown to be more resistant to infestation by ticks than the two commercial breeds. NA ewes expressed IL-1β more at tick attachment sites compared to Dorpers. The NA breed was also more likely to upregulate the expression of the CCL2, CCL26 and IL-8 genes at tick attachment sites compared to control sites than the other breeds. The results of this study gave an indication that cytokines are involved in immune responses to tick challenge and laid a foundation for further studies under controlled challenge conditions.

Methods in isolation and characterization of bovine monocytes and macrophages

Monocytes and macrophages belong to the mononuclear phagocyte system and play important roles in both physiological and pathological processes. The cells belonging to the monocyte/macrophage system are structurally and functionally heterogeneous. Several subsets of monocytes have been previously identified in mammalian blood, generating different subpopulations of macrophages in tissues. Although their distribution and phenotype are similar to their human counterpart, bovine monocytes and macrophages feature differences in both functions and purification procedures. The specific roles that monocytes and macrophages fulfil in several important diseases of bovine species, including among the others tuberculosis and paratuberculosis, brucellosis or the disease related to peripartum, remain still partially elusive. The purpose of this review is to discuss the current knowledge of bovine monocytes and macrophages. We will describe methods for their purification and characterization of their major functions, including chemotaxis, phagocytosis and killing, oxidative burst, apoptosis and necrosis. An overview of the flow cytometry and morphological procedures, including cytology, histology and immunohistochemistry, that are currently utilized to describe monocyte and macrophage main populations and functions is presented as well.

Development of a CRISPR/Cas9 system against ruminant animal brucellosis

BACKGROUND

Brucellosis, caused by several Brucella species, such as the bacterium Brucella melitensis, is considered one of the most severe zoonotic diseases worldwide. Not only does it affect ruminant animal populations, leading to a substantial financial burden for stockbreeders, but also poses severe public health issues. For almost four decades in southern Europe and elsewhere, eradication of the disease has been based on ambiguously effective programs, rendering massive sanitation of livestock urgent and indispensable. Gene therapy, which has been proved effective in the clinic, could possibly constitute an alternative option towards a permanent cure for brucellosis, by aiding in the deletion or inactivation of genes associated with the replication of Brucella within the host cells.

RESULTS

We infected ovine macrophages with B.melitensis, to simulate the host cell/microorganism interaction in vitro, and transduced the infected cells with CRISPR/Cas9 lentiviral vectors that target Brucella's RNA polymerase subunit A (RpolA) or virulence-associated gene virB10 at a multiplicity of infection of 60. We demonstrate a significant decrease in the bacterial load per cell when infected cells are transduced with the RpolA vector and that the number of internalized brucellae per cell remains unaffected when macrophages are transduced with a conventional lentiviral vector expressing the green fluorescence protein, thus underlining the bactericidal effect of our CRISPR/Cas9 system.

CONCLUSIONS

Pending in vivo verification of our findings, overall, these results may prove critical not only for the treatment of human brucellosis, but for other infectious diseases in general.

A Cellular Model of Infection with Brucella melitensis in Ovine Macrophages: Novel Insights for Intracellular Bacterial Detection

Intracellular bacteria provoking zoonoses, such as those of the genus Brucella, present a host cell tropism mostly limited to the monocyte/macrophage lineage, leading to chronic inflammatory reactions, difficult-to-eradicate-infections, and widespread prevalence among ruminants. Eradication of brucellosis has been based on programs that translate into a substantial financial burden for both the authorities and stockbreeders, if not strictly followed. To this end, we sought to create an in vitro cell model that could be utilized as future reference for adequately measuring the number of engulfed brucellae/cell, using peripheral blood-derived sheep macrophages infected with B. melitensis at decimal multiplicities of infection (MOI = 5000-5), to simulate the host cell/microorganism interaction and monitor bacterial loads up to 6 days post-infection. We show that the MOI = 5000 leads to high numbers of engulfed bacteria without affecting macrophages’ viability and that the minimum detection limit of our Real-Time PCR assay was 3.97 ± 5.58 brucellae/cell. Moreover, we observed a time-associated, significant gradual reduction in bacterial loads from Day 2 to Day 6 post-infection (p = 0.0013), as part of the natural bactericidal properties of macrophages. Overall, the work presented here constitutes a reliable in vitro cell model of Brucella melitensis for research purposes that can be utilized to adequately measure the number of engulfed brucellae/cell and provides insights towards future utilization of molecular biology-based methods for detection of Brucella.

Efficient Transduction and Expansion of Ovine Macrophages for Gene Therapy Implementations

A number of bacteria provoking zoonotic diseases present intracellular survival and a host cell tropism limited to the monocyte/macrophage lineage. Thus, infection is rendered difficult to eradicate, causing chronic inflammatory reactions to the host and widespread prevalence. Although self-inactivating lentiviral vectors have been successfully tested in the clinic against virally-induced human infectious diseases, little is known about the transduction susceptibility of ruminant animal phagocytes that play a critical role in the outbreak of zoonotic diseases such as brucellosis. In view of the development of a lentiviral vector-based platform targeting and inactivating specific genetic features of intracellular bacteria, we have tested the transducibility of ovine macrophages in terms of transgene expression and vector copy number (VCN). We show that ovine macrophages are relatively resistant to transduction even at a high multiplicity of infection with a conventional lentiviral vector expressing the green fluorescence protein and that addition of transduction enhancers, such as polybrene, increases transgene expression even after a one-week culture of the transduced cells in vitro. Overall, we demonstrate that ovine macrophages may be efficiently expanded and transduced in culture, thus providing the benchmark for gene therapy applications for zoonotic diseases.

Selection of stably expressed internal control genes in circulating polymorphoneutrophils of periparturient Sahiwal (Bos indicus) cows

Around parturition, animal undergoes a state of immune-suppression and become more susceptible to pathogens. This study was aimed to identify appropriate internal control genes (ICG) for transcriptional studies in polymorphoneutrophils (PMN)of Sahiwal (Bos indicus) cows during the periparturient period. The study involved 4 periparturient Sahiwal cows (–21 days to 0 day to +21 days relative to parturition) and 10 known internal control genes (ICG)from different functional classes. ForqPCR reaction following conditions were employed: 2 min at 50°C, 10 min at 95 °C, 40 cycles of 15 s at 95 °C (denaturation) and 1 min at 60°C (annealing + extension).To measure the transcript stability of 10 ICG genes, threesoftwareprogrammes;geNorm, Normfinder and BestKeeper were used. All the genes showed acceptable expression stability as per the recommended threshold values. The geNorm analysis showed RPS9, RPS15A and RPS23 genes to be most stably expressed while HMBS and HPRT1 showed least stability.The expression stability for all the 10 ICG were within the acceptable range (M value <1.5).The pair wise variation analysis recommended the use of RPS9, RPS15Agenes for normalization. The geNorm and Normfinder identified same set of most and least stable genes. BestKeeper analysis identified ACTB, RPS9/ B2M,RPS23, RPS15A genes showing consistent expression while HMBS and HPRT1 showed relatively much higher variability. Our analysis identified RPS9, RPS15Aand ACTBgenesassuitable ICG to provide accurate normalization totranscriptional dataof PMN during the periparturient stages of Indian cows.

A tissue-based approach to selection of reference genes for quantitative real-time PCR in a sheep osteoporosis model

BACKGROUND

In order to better understand the multifactorial nature of osteoporosis, animal models are utilized and compared to healthy controls. Female sheep are well established as a model for osteoporosis induced by ovariectomy, calcium and vitamin D low diet, application of steroids, or a combination of these treatments. Transcriptional studies can be performed by applying quantitative real time PCR (RT-qPCR). RT-qPCR estimates mRNA-levels of target genes in relation to reference genes. A chosen set of reference genes should not show variation under experimental conditions. Currently, no standard reference genes are accepted for all tissue types and experimental conditions. Studies examining reference genes for sheep are rare and only one study described stable reference in mandibular bone. However, this type of bone differs from trabecular bone where most osteoporotic fractures occur. The present study aimed at identifying a set of reference genes for relative quantification of transcriptional activity of ovine spine bone and ovine in vitro differentiated mesenchymal stromal cells (MSC) for reliable comparability.

METHODS

Twelve candidate reference genes belonging to different functional classes were selected and their expression was measured from cultured ovMSCs (n = 18) and ovine bone samples (n = 16), respectively. RefFinder was used to rank the candidate genes.

RESULTS

We identified B2M, GAPDH, RPL19 and YWHAZ as the best combination of reference genes for normalization of RT-qPCR results for transcriptional analyses of these ovine samples.

CONCLUSION

This study demonstrates the importance of applying a set of reference genes for RT-qPCR analysis in sheep. Based on our data we recommend using four identified reference genes for relative quantification of gene expression studies in ovine bone or for in vitro experiments with osteogenically differentiated ovine MSCs.

Assessment of RNA Stability in Postmortem Tissue from New-Born Lambs

The recovery of high quality RNA from postmortem tissue is crucial to gene expression analyses. The acquisition of postmortem tissue has inherent time delays and, hence, understanding the temporal variation in the stability of total RNA is imperative. This experiment aimed: ( 1 ) to qualitatively and quantitatively assess the integrity of total RNA derived from a range of new-born ovine tissues (liver, spleen, thyroid, skeletal muscle, ileum, and perirenal adipose tissue) which were stored at ambient temperature until extraction at 0, 3, 6, and 9 h postmortem; and ( 2 ) to analyze the stability of the reference gene(s) and expression of specific target genes in these tissues. Postmortem sampling time resulted in variable reductions in the relative integrity number (RIN) values across the tissues, ranging from 0.9 to 1.8% in liver, spleen, skeletal muscle, and ileum to 5.7-11.1% in the thyroid and perirenal adipose tissues, respectively (P < 0.05). In conclusion, tissues with small reductions in RIN value can exhibit disproportionately large differences in the normalization factor used to calculate the target gene expression. Hence, changes in transcript abundance due to RNA degradation are not always sufficiently buffered through normalization with reference genes. The normalization factor should be presented alongside the RIN value in postmortem tissue studies.

PrPC expression and prion seeding activity in the alimentary tract and lymphoid tissue of deer

The agent responsible for prion diseases is a misfolded form of a normal protein (PrPC). The prion hypothesis stipulates that PrPC must be present for the disease to manifest. Cervid populations across the world are infected with chronic wasting disease, a horizontally-transmissible prion disease that is likely spread via oral exposure to infectious prions (PrPCWD). Though PrPCWD has been identified in many tissues, there has been little effort to characterize the overall PrPC expression in cervids and its relationship to PrPCWD accumulation. We used immunohistochemistry (IHC), western blot and enzyme-linked immunosorbent assay to describe PrPC expression in naïve white-tailed deer. We used real-time, quaking-induced conversion (RT-QuIC) to detect prion seeding activity in CWD-infected deer. We assessed tissues comprising the alimentary tract, alimentary-associated lymphoid tissue and systemic lymphoid tissue from 5 naïve deer. PrPC was expressed in all tissues, though expression was often very low compared to the level in the CNS. IHC identified specific cell types wherein PrPC expression is very high. To compare the distribution of PrPC to PrPCWD, we examined 5 deer with advanced CWD infection. Using RT-QuIC, we detected prion seeding activity in all 21 tissues. In 3 subclinical deer sacrificed 4 months post-inoculation, we detected PrPCWD consistently in alimentary-associated lymphoid tissue, irregularly in alimentary tract tissues, and not at all in the brain. Contrary to our hypothesis that PrPC levels dictate prion accumulation, PrPC expression was higher in the lower gastrointestinal tissues than in the alimentary-associated lymphoid system and was higher in salivary glands than in the oropharyngeal lymphoid tissue. These data suggest that PrPC expression is not the sole driver of prion accumulation and that alimentary tract tissues accumulate prions before centrifugal spread from the brain occurs.

Selection of reference genes for expression analysis using RT-qPCR in the dissemination system of Heliothis virescens ascovirus 3 h (HvAV-3h)

Ascoviruses are double-stranded DNA viruses that mainly infect noctuid larvae, and are transmitted by the parasitoid wasp Microplitis similis Lyle. Ascovirus-parasitoids wasp-noctuid insects constitute the dissemination system. Selection of suitable reference genes for the dissemination system could play an important role in elucidating the pathogenic molecular mechanisms of ascovirus. Unfortunately, such studies on potential reference genes in the dissemination system of ascoviruses are lacking. In the present study, we evaluated 11 candidate reference genes: β-actin1 (ACT1), β-actin2 (ACT2), elongation factor 1 (EF1), elongation factor 2 (EF2), ribosomal protein L10 (L10), ribosomal protein L17A (L17A), superoxide dismutase (SOD), 28S ribosome (28S), Tubulin (TUB) and 18S ribosome (18S). The samples were originally from various virus concentrations and points-in-time of experimental treatments using RefFinder and four algorithms. The results showed that EF1 was the most stable internal gene in S. exigua and M. similis and that EF2 was the most stable in the IOZCAS-Spex-II-A cell line, and the stability of reference genes were confirmed via the expression levels of two inhibitor of apoptosis-like (iap-like) genes from Heliothis virescens ascovirus 3 h (HvAV-3h). This study provides a crucial basis for future research that explores the molecular mechanisms of the pathogenesis of ascoviruses.

Royal jelly may improve the metabolism of glucose and redox state of ovine oocytes matured in vitro and embryonic development following in vitro fertilization

The aim of this study was to investigate the effect of different concentrations of royal jelly (RJ) on in vitro maturation (IVM), fertilization, cleavage, blastocyst rates, glutathione (GSH) content in ovine oocyte, mRNA abundance of antioxidant enzymes in both oocyte and cumulus, and glucose metabolism-related genes in cumulus cells. In vitro maturation of oocyte was performed in the presence of control (RJ₀), 2.5 (RJ_2.5), 5 (RJ₅), and 10 (RJ₁₀) mg/mL of RJ. Nuclear status, intracellular GSH content in oocytes, and mRNA abundance of selected genes were evaluated following 24 hours of IVM. Following the IVM, fertilization and embryo culture were carried out in all the groups and embryonic development was examined. The addition of 10-mg/mL RJ to maturation media not only yielded a higher number of oocytes at MII stage but also showed an increased level of intracellular GSH content than did RJ_2.5 and control groups. Fertilization, cleavage, and blastocyst rate were higher in the RJ₁₀ treatment group in comparison to the control one. In cumulus cells, the expression of PFKM, PFKL, and G6PDH were increased following the addition of RJ to the maturation media. Supplementation of 10-mg/mL RJ to IVM medium increased the GPx mRNA abundance in both oocyte and cumulus cells and SOD expression in the cumulus cells. The CAT mRNA abundance was not influenced by the addition of RJ to the maturation media in either oocyte or cumulus cells. It seems that the improvement of oocyte maturation and its subsequent development in RJ₁₀ group may be associated with amelioration of redox status in the oocytes and activation of glucose metabolic pathways in their surrounding cumulus cells.

Validation of putative reference genes for gene expression studies in heat stressed and α-MSH treated melanocyte cells of Bos indicus using real-time quantitative PCR

Normalization of cellular mRNA data using internal reference gene (IRG) is an essential step in expression analysis studies. MIQE guidelines ensure that the choice and appropriateness of IRG should be validated for particular tissues or cell types and specific experimental designs. The objective of the present study was to assess 15 IRGs from different functional classes that could serve as best IRGs for Bos indicus (Tharparkar cattle) melanocyte cells under heat stress and hormonal treatment. We implemented the use of geNorm, NormFinder and BestKeeper algorithm to measure the stability of the gene transcript. A total of 15 IRGs (ACTB, BZM, EEF1, GAPDH, GTP, HMBS, HPRT, RPL22, RPL4, RPS15, RPS18, RPS23, RPS9, UBC and UXT) from different functional classes were evaluated. Pair wise comparisons using geNorm revealed that HPRT and RPS23 were the most stable combination of IRGs with M-value of 0.29 followed by UXT (0.30) and RPL4 (0.31). The NormFinder analysis also identified the same set of stably expressed genes (UXT, RPL4, RPS23 and HPRT); however, the rank order was little different. The UXT gene showed lowest crossing point SD and CV values of 0.30 and 1.17, respectively indicating its maximum expression stability through BestKeeper analysis. The present study indicated that, ACTB and HMB were not reliable IRGs for melanocytes cells on account of their lower expression stability. Current study further revealed that UXT, HPRT and RPS23 are the best IRGs for normalization of qPCR data in Bos indicus melanocyte cells under heat stress and hormonal treatment.

Prion Type-Dependent Deposition of PRNP Allelic Products in Heterozygous Sheep

Susceptibility or resistance to prion infection in humans and animals depends on single prion protein (PrP) amino acid substitutions in the host, but the agent's modulating role has not been well investigated. Compared to disease incubation times in wild-type homozygous ARQ/ARQ (where each triplet represents the amino acids at codons 136, 154, and 171, respectively) sheep, scrapie susceptibility is reduced to near resistance in ARR/ARR animals while it is strongly enhanced in VRQ/VRQ carriers. Heterozygous ARR/VRQ animals exhibit delayed incubation periods. In bovine spongiform encephalopathy (BSE) infection, the polymorphism effect is quite different although the ARR allotype remains the least susceptible. In this study, PrP allotype composition in protease-resistant prion protein (PrP(res)) from brain of heterozygous ARR/VRQ scrapie-infected sheep was compared with that of BSE-infected sheep with a similar genotype. A triplex Western blotting technique was used to estimate the two allotype PrP fractions in PrP(res) material from BSE-infected ARR/VRQ sheep. PrP(res) in BSE contained equimolar amounts of VRQ- and ARR-PrP, which contrasts with the excess (>95%) VRQ-PrP fraction found in PrP in scrapie. This is evidence that transmissible spongiform encephalopathy (TSE) agent properties alone, perhaps structural aspects of prions (such as PrP amino acid sequence variants and PrP conformational state), determine the polymorphic dependence of the PrP(res) accumulation process in prion formation as well as the disease-associated phenotypic expressions in the host.

IMPORTANCE

Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative and transmissible diseases caused by prions. Amino acid sequence variants of the prion protein (PrP) determine transmissibility in the hosts, as has been shown for classical scrapie in sheep. Each individual produces a separate PrP molecule from its two PrP gene copies. Heterozygous scrapie-infected sheep that produce two PrP variants associated with opposite scrapie susceptibilities (136V-PrP variant, high; 171R-PrP variant, very low) contain in their prion material over 95% of the 136V PrP variant. However, when these sheep are infected with prions from cattle (bovine spongiform encephalopathy [BSE]), both PrP variants occur in equal ratios. This shows that the infecting prion type determines the accumulating PrP variant ratio in the heterozygous host. While the host's PrP is considered a determining factor, these results emphasize that prion structure plays a role during host infection and that PrP variant involvement in prions of heterozygous carriers is a critical field for understanding prion formation.

Developmental Expression and Glucocorticoid Control of the Leptin Receptor in Fetal Ovine Lung

The effects of endogenous and synthetic glucocorticoids on fetal lung maturation are well-established, although the role of leptin in lung development before birth is unclear. This study examined mRNA and protein levels of the signalling long-form leptin receptor (Ob-Rb) in fetal ovine lungs towards term, and after experimental manipulation of glucocorticoid levels in utero by fetal cortisol infusion or maternal dexamethasone treatment. In fetal ovine lungs, Ob-Rb protein was localised to bronchiolar epithelium, bronchial cartilage, vascular endothelium, alveolar macrophages and type II pneumocytes. Pulmonary Ob-Rb mRNA abundance increased between 100 (0.69 fractional gestational age) and 144 days (0.99) of gestation, and by 2-4-fold in response to fetal cortisol infusion and maternal dexamethasone treatment. In contrast, pulmonary Ob-Rb protein levels decreased near term and were halved by glucocorticoid treatment, without any significant change in phosphorylated signal transducer and activator of transcription-3 (pSTAT3) at Ser727, total STAT3 or the pulmonary pSTAT3:STAT3 ratio. Leptin mRNA was undetectable in fetal ovine lungs at the gestational ages studied. These findings demonstrate differential control of pulmonary Ob-Rb transcript abundance and protein translation, and/or post-translational processing, by glucocorticoids in utero. Localisation of Ob-Rb in the fetal ovine lungs, including alveolar type II pneumocytes, suggests a role for leptin signalling in the control of lung growth and maturation before birth.

Evaluation of reference gene suitability for quantitative expression analysis by quantitative polymerase chain reaction in the mandibular condyle of sheep

Reference genes are commonly used as a reliable approach to normalize the results of quantitative polymerase chain reaction (qPCR), and to reduce errors in the relative quantification of gene expression. Suitable reference genes belonging to numerous functional classes have been identified for various types of species and tissue. However, little is currently known regarding the most suitable reference genes for bone, specifically for the sheep mandibular condyle. Sheep are important for the study of human bone diseases, particularly for temporomandibular diseases. The present study aimed to identify a set of reference genes suitable for the normalization of qPCR data from the mandibular condyle of sheep. A total of 12 reference genes belonging to various functional classes were selected, and the expression stability of the reference genes was determined in both the normal and fractured area of the sheep mandibular condyle. RefFinder, which integrates the following currently available computational algorithms: geNorm, NormFinder, BestKeeper, and the comparative ΔCt method, was used to compare and rank the candidate reference genes. The results obtained from the four methods demonstrated a similar trend: RPL19, ACTB, and PGK1 were the most stably expressed reference genes in the sheep mandibular condyle. As determined by RefFinder comprehensive analysis, the results of the present study suggested that RPL19 is the most suitable reference gene for studies associated with the sheep mandibular condyle. In addition, ACTB and PGK1 may be considered suitable alternatives.

The dilution effect and the importance of selecting the right internal control genes for RT-qPCR: a paradigmatic approach in fetal sheep

BACKGROUND

The key to understanding changes in gene expression levels using reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR) relies on the ability to rationalize the technique using internal control genes (ICGs). However, the use of ICGs has become increasingly problematic given that any genes, including housekeeping genes, thought to be stable across different tissue types, ages and treatment protocols, can be regulated at transcriptomic level. Our interest in prenatal glucocorticoid (GC) effects on fetal growth has resulted in our investigation of suitable ICGs relevant in this model. The usefulness of RNA18S, ACTB, HPRT1, RPLP0, PPIA and TUBB as ICGs was analyzed according to effects of early dexamethasone (DEX) treatment, gender, and gestational age by two approaches: (1) the classical approach where raw (i.e., not normalized) RT-qPCR data of tested ICGs were statistically analyzed and the best ICG selected based on absence of any significant effect; (2) used of published algorithms. For the latter the geNorm Visual Basic application was mainly used, but data were also analyzed by Normfinder and Bestkeeper. In order to account for confounding effects on the geNorm analysis due to co-regulation among ICGs tested, network analysis was performed using Ingenuity Pathway Analysis software. The expression of RNA18S, the most abundant transcript, and correlation of ICGs with RNA18S, total RNA, and liver-specific genes were also performed to assess potential dilution effect of raw RT-qPCR data. The effect of the two approaches used to select the best ICG(s) was compared by normalization of NR3C1 (glucocorticoid receptor) mRNA expression, as an example for a target gene.

RESULTS

Raw RT-qPCR data of all the tested ICGs was significantly reduced across gestation. TUBB was the only ICG that was affected by DEX treatment. Using approach (1) all tested ICGs would have been rejected because they would initially appear as not reliable for normalization. However, geNorm analysis (approach 2) of the ICGs indicated that the geometrical mean of PPIA, HPRT1, RNA18S and RPLPO can be considered a reliable approach for normalization of target genes in both control and DEX treated groups. Different subset of ICGs were tested for normalization of NR3C1 expression and, despite the overall pattern of the mean was not extremely different, the statistical analysis uncovered a significant influence of the use of different normalization approaches on the expression of the target gene. We observed a decrease of total RNA through gestation, a lower decrease in raw RT-qPCR data of the two rRNA measured compared to ICGs, and a positive correlation between raw RT-qPCR data of ICGs and total RNA. Based on the same amount of total RNA to performed RT-qPCR analysis, those data indicated that other mRNA might have had a large increase in expression and, as consequence, had artificially diluted the stably expressed genes, such as ICGs. This point was demonstrated by a significant negative correlation of raw RT-qPCR data between ICGs and liver-specific genes.

CONCLUSION

The study confirmed the necessity of assessing multiple ICGs using algorithms in order to obtain a reliable normalization of RT-qPCR data. Our data indicated that the use of the geometrical mean of PPIA, HPRT1, RNA18S and RPLPO can provide a reliable normalization for the proposed study. Furthermore, the dilution effect observed support the unreliability of the classical approach to test ICGs. Finally, the observed change in the composition of RNA species through time reveals the limitation of the use of ICGs to normalize RT-qPCR data, especially if absolute quantification is required.

Reference gene screening for analyzing gene expression across goat tissue

Real-time quantitative PCR (qRT-PCR) is one of the important methods for investigating the changes in mRNA expression levels in cells and tissues. Selection of the proper reference genes is very important when calibrating the results of real-time quantitative PCR. Studies on the selection of reference genes in goat tissues are limited, despite the economic importance of their meat and dairy products. We used real-time quantitative PCR to detect the expression levels of eight reference gene candidates (18S, TBP, HMBS, YWHAZ, ACTB, HPRT1, GAPDH and EEF1A2) in ten tissues types sourced from Boer goats. The optimal reference gene combination was selected according to the results determined by geNorm, NormFinder and Bestkeeper software packages. The analyses showed that tissue is an important variability factor in genes expression stability. When all tissues were considered, 18S, TBP and HMBS is the optimal reference combination for calibrating quantitative PCR analysis of gene expression from goat tissues. Dividing data set by tissues, ACTB was the most stable in stomach, small intestine and ovary, 18S in heart and spleen, HMBS in uterus and lung, TBP in liver, HPRT1 in kidney and GAPDH in muscle. Overall, this study provided valuable information about the goat reference genes that can be used in order to perform a proper normalisation when relative quantification by qRT-PCR studies is undertaken.

Gene expression profiling of mesenteric lymph nodes from sheep with natural scrapie

BACKGROUND

Prion diseases are characterized by the accumulation of the pathogenic PrPSc protein, mainly in the brain and the lymphoreticular system. Although prions multiply/accumulate in the lymph nodes without any detectable pathology, transcriptional changes in this tissue may reflect biological processes that contribute to the molecular pathogenesis of prion diseases. Little is known about the molecular processes that occur in the lymphoreticular system in early and late stages of prion disease. We performed a microarray-based study to identify genes that are differentially expressed at different disease stages in the mesenteric lymph node of sheep naturally infected with scrapie. Oligo DNA microarrays were used to identify gene-expression profiles in the early/middle (preclinical) and late (clinical) stages of the disease.

RESULTS

In the clinical stage of the disease, we detected 105 genes that were differentially expressed (≥2-fold change in expression). Of these, 43 were upregulated and 62 downregulated as compared with age-matched negative controls. Fewer genes (50) were differentially expressed in the preclinical stage of the disease. Gene Ontology enrichment analysis revealed that the differentially expressed genes were largely associated with the following terms: glycoprotein, extracellular region, disulfide bond, cell cycle and extracellular matrix. Moreover, some of the annotated genes could be grouped into 3 specific signaling pathways: focal adhesion, PPAR signaling and ECM-receptor interaction. We discuss the relationship between the observed gene expression profiles and PrPSc deposition and the potential involvement in the pathogenesis of scrapie of 7 specific differentially expressed genes whose expression levels were confirmed by real time-PCR.

CONCLUSIONS

The present findings identify new genes that may be involved in the pathogenesis of natural scrapie infection in the lymphoreticular system, and confirm previous reports describing scrapie-induced alterations in the expression of genes involved in protein misfolding, angiogenesis and the oxidative stress response. Further studies will be necessary to determine the role of these genes in prion replication, dissemination and in the response of the organism to this disease.

The developmental transition of ovine adipose tissue through early life

AIM

Hypothermia induced by cold exposure at birth is prevented in sheep by the rapid onset of non-shivering thermogenesis in brown adipose tissue (BAT). Changes in adipose tissue composition in early life are therefore essential for survival but also influence adiposity in later life and were thus examined in detail during early development.

METHODS

Changes in adipose composition were investigated by immunohistochemistry and qRT-PCR between the period from the first appearance of adipose in the mid gestation foetus, through birth and up to 1 month of age.

RESULTS

We identified four distinct phases of development, each associated with pronounced changes in tissue histology and in distribution of the BAT specific uncoupling protein (UCP)1. At mid gestation, perirenal adipose tissue exhibited a dense proliferative, structure marked by high expression of KI-67 but with no UCP1 or visible lipid droplets. By late gestation large quantities of UCP1 were present, lipid storage was evident and expression of BAT-related genes were abundant (e.g. prolactin and β3 receptors). Subsequently, within 12 h of birth, the depot was largely depleted of lipid and expression of genes such as UCP1, PGC1α, CIDEA peaked. By 30 days UCP1 was undetectable and the depot contained large lipid droplets; however, genes characteristic of BAT (e.g. PRDM16 and BMP7) and most characteristic of white adipose tissue (e.g. leptin and RIP140) were still abundant.

CONCLUSION

Adipose tissue undergoes profound compositional changes in early life, of which an increased understanding could offer potential interventions to retain BAT in later life.

Effects of feeding selenium-enriched alfalfa hay on immunity and health of weaned beef calves

Previously, we reported that feeding selenium (Se)-enriched forage improves antibody titers in mature beef cows, and whole-blood Se concentrations and growth rates in weaned beef calves. Our current objective was to test whether beef calves fed Se-enriched alfalfa hay during the transition period between weaning and movement to a feedlot also have improved immune responses and slaughter weights. Recently weaned beef calves (n = 60) were fed an alfalfa-hay-based diet for 7 weeks, which was harvested from fields fertilized with sodium selenate at 0, 22.5, 45.0, or 89.9 g Se/ha. All calves were immunized with J-5 Escherichia coli bacterin. Serum was collected for antibody titers 2 weeks after the third immunization. Whole-blood neutrophils collected at 6 or 7 weeks were evaluated for total antioxidant potential, bacterial killing activity, and expression of genes associated with selenoproteins and innate immunity. Calves fed the highest versus the lowest level of Se-enriched alfalfa hay had higher antibody titers (P = 0.02), thioredoxin reductase-2 mRNA levels (P = 0.07), and a greater neutrophil total antioxidant potential (P = 0.10), whereas mRNA levels of interleukin-8 receptor (P = 0.02), L-selectin (P = 0.07), and thioredoxin reductase-1 (P = 0.07) were lower. In the feedlot, calves previously fed the highest-Se forage had lower mortality (P = 0.04) and greater slaughter weights (P = 0.02). Our results suggest that, in areas with low-forage Se concentrations, feeding beef calves Se-enriched alfalfa hay during the weaning transition period improves vaccination responses and subsequent growth and survival in the feedlot.

Peri-pubertal gonadotropin-releasing hormone agonist treatment affects sex biased gene expression of amygdala in sheep

The nature of hormonal involvement in pubertal brain development has attracted wide interest. Structural changes within the brain that occur during pubertal development appear mainly in regions closely linked with emotion, motivation and cognitive functions. Using a sheep model, we have previously shown that peri-pubertal pharmacological blockade of gonadotropin releasing hormone (GnRH) receptors, results in exaggerated sex-differences in cognitive executive function and emotional control, as well as sex and hemisphere specific patterns of expression of hippocampal genes associated with synaptic plasticity and endocrine signaling. In this study, we explored effects of this treatment regime on the gene expression profile of the ovine amygdala. The study was conducted with 30 same-sex twin lambs (14 female and 16 male), half of which were treated with the GnRH agonist (GnRHa) goserelin acetate every 4th week, beginning before puberty, until approximately 50 weeks of age. Gene expression profiles of the left and right amygdala were measured using 8×15 K Agilent ovine microarrays. Differential expression of selected genes was confirmed by qRT-PCR (Quantitative real time PCR). Networking analyses and Gene Ontology (GO) Term analyses were performed with Ingenuity Pathway Analysis (IPA), version 7.5 and DAVID (Database for Annotation, Visualization and integrated Discovery) version 6.7 software packages, respectively. GnRHa treatment was associated with significant sex- and hemisphere-specific differential patterns of gene expression. GnRHa treatment was associated with differential expression of 432 (|logFC|>0.3, adj. p value <0.05) and 46 (p value <0.0.5) genes in the left and right amygdala, respectively, of female animals, relative to the reference sample which consisted of all a pooled sample from control and treated animals of both sexes. No genes were found to be differentially expressed as a result of GnRHa treatment in the male animals. The results indicated that GnRH may, directly and/or indirectly, be involved in the regulation of sex- and hemisphere-specific differential expression of genes in the amygdala. This finding should be considered when long-term peri-pubertal GnRHa treatment is used in children.

Evaluation of internal reference genes for quantitative expression analysis by real-time reverse transcription-PCR in somatic cells from goat milk

Reverse transcription (RT) quantitative real-time PCR (qPCR) is the most accurate and easy-to-perform technique to measure the expression level of a selected gene of interest by quantifying mRNA transcripts. The use of reference genes is commonly accepted as the most reliable approach to normalize RT-qPCR data and reduce possible errors generated in the quantification of gene expression. The optimal number and choice of reference genes are experimentally validated for specific tissues or cell types and experimental designs. To date, data on qPCR normalization in goats are scarce and the most suitable reference genes in this species have been identified for only a limited number of tissues. The aim of this study was to determine an optimal combination of stably expressed reference genes in caprine milk somatic cells (MSC) from healthy and infected mammary glands. For the purpose, we performed RT-qPCR for 10 commonly used reference genes from various functional classes and then determined their expression level in MSC from goats intramammary challenged with Staphylococcus aureus and in MSC from healthy controls, with a view to select genes whose stability would be unaffected under infection conditions. The geNorm and NormFinder algorithms were used for validating the reference genes. Furthermore, to demonstrate the importance of normalization of gene expression with appropriate reference genes, we tested the effect of using a combination of the least stable genes for expression analysis evaluation. On the basis of our evaluation, we recommend the use of a panel of reference genes that should include G6PD, YWHAZ, and ACTB for caprine MSC gene expression profiling. The expression of the 2 genes of interest, pentraxin-related protein (PTX3) and secreted phosphoprotein 1 (SPP1), was evaluated by RT-qPCR in all samples collected pre- and postinfection, and the recommended reference genes were used to normalize the data. Our study provides a validated panel of optimal reference genes for the identification of genes differentially expressed by qRT-PCR in caprine MSC. Moreover, we provided a set of intron-spanning primer sequences that could be suitable for gene expression experiments using SYBR Green chemistry on other caprine tissues and cells.

Selenium supplementation alters gene expression profiles associated with innate immunity in whole-blood neutrophils of sheep

Footrot (FR) is a common, contagious bacterial disease of sheep that results in lameness and significant economic losses for producers. We previously reported that sheep affected with FR have lower whole-blood (WB) selenium (Se) concentrations and that Se supplementation in conjunction with routine control practices accelerates recovery from FR. To determine whether oral Se-yeast administered at supranutritional levels (>4.9 mg Se/week) alters the ability of sheep to resist or recover from FR infection, 60 ewes with and 60 ewes without FR were drenched once weekly for 62.5 weeks with 0, 4.9, 14.7, or 24.5 mg organic Se-yeast (30 ewes per treatment group). Footrot prevalence and severity were measured at 0, 20, 28, 40, and 60 weeks of Se supplementation. Genomic expression of eight WB-neutrophil genes for selenoproteins and seven WB-neutrophil genes for proteins involved in innate immunity was determined at the end of the treatment period using SYBR Green and quantitative polymerase chain reaction methodology. Supranutritional Se-yeast supplementation successfully increased Se status in sheep but did not prevent FR. Supranutritional Se-yeast supplementation increased WB-neutrophil expression of genes involved in innate immunity: L-selectin, interleukin-8 receptor, and toll-like receptor 4, which were or tended to be lower in ewes affected with FR. Furthermore, supranutritional Se-yeast supplementation altered the expression of selenoprotein genes involved in innate immunity, increasing selenoprotein S and glutathione peroxidase 4 and decreasing iodothyronine deiodinases 2 and 3. In conclusion, supranutritional Se-yeast supplementation does not prevent FR, but does alter WB-neutrophil gene expression profiles associated with innate immunity, including reversing those impacted by FR.

Identification of stable reference genes for gene expression studies using quantitative real time PCR in buffalo oocytes and embryos

The present study was aimed to validate expression stability of 6 housekeeping genes (viz. YWHAZ, SDHA, GAPDH, RPS15, RPS18 and RN18S1) in the oocytes and embryos of different stages in buffalo. A modified Trizol protocol was optimized for RNA isolation from as few as five oocytes. The expression level of selected genes was studied by an optimized real time PCR using DCT method and their stability of expression was evaluated by Microsoft Excel based visual application, geNORM. The analysis revealed that the RPS15 and GAPDH were the most stable genes across different samples. Also, the geometric mean of three genes (i.e. RPS15,RPS18 and GAPDH) were found suitable for normalization of real time PCR data from buffalo oocytes⁄embryos. The information would help in more accurate interpretation of gene expression data from oocytes⁄embryos towards understanding the molecular events in these cells during development.

Expression analysis of 13 ovine immune response candidate genes in Visna/Maedi disease progression

Visna/Maedi virus (VMV) is a lentivirus that infects cells of the monocyte/macrophage lineage in sheep. Infection with VMV may lead to Visna/Maedi (VM) disease, which causes a multisystemic inflammatory disorder causing pneumonia, encephalitis, mastitis and arthritis. The role of ovine immune response genes in the development of VM disease is not fully understood. In this work, sheep of the Rasa Aragonesa breed were divided into two groups depending on the presence/absence of VM-characteristic clinical lesions in the aforementioned organs and the relative levels of candidate gene expression, including cytokines and innate immunity loci were measured by qPCR in the lung and udder. Sheep with lung lesions showed differential expression in five target genes: CCR5, TLR7, and TLR8 were up regulated and IL2 and TNFα down regulated. TNFα up regulation was detected in the udder.

Maternal Diet during Pregnancy Induces Gene Expression and DNA Methylation Changes in Fetal Tissues in Sheep

Studies in rats and mice have established that maternal nutrition induces epigenetic modifications, sometimes permanently, that alter gene expression in the fetus, which in turn leads to phenotypic changes. However, limited data is available on the influence of maternal diet on epigenetic modifications and gene expression in sheep. Therefore, the objectives of this study were to investigate the impact of different maternal dietary energy sources on the expression of imprinted genes in fetuses in sheep. Ewes were naturally bred to a single sire and from days 67 ± 3 of gestation until necropsy (days 130 ± 1), they were fed one of three diets of alfalfa haylage (HY; fiber), corn (CN; starch), or dried corn distiller’s grains (DG; fiber plus protein plus fat). A total of 26 fetuses were removed from the dams and longissimus dorsi, semitendinosus, perirenal adipose depot, and subcutaneous adipose depot tissues were collected for expression and DNA methylation analyses. Expression analysis of nine imprinted genes and three DNA methyltransferase (DNMTs) genes showed significant effects of the different maternal diets on the expression of these genes. The methylation levels of CpG islands of both IGF2R and H19 were higher in HY and DG than CN fetuses in both males and females. This result is consistent with the low amino acid content of the CN diet, a source of methyl group donors, compared to HY and DG diets. Thus, results of this study provide evidence of association between maternal nutrition during pregnancy and transcriptomic and epigenomic alterations of imprinted genes and DNMTs in the fetal tissues.

Gene and protein patterns of potential prion-related markers in the central nervous system of clinical and preclinical infected sheep

The molecular pathogenic mechanisms of prion diseases are far from clear. Genomic analyses have revealed genetic biomarkers potentially involved in prion neuropathology in naturally scrapie-infected sheep, a good animal model of infectious prionopathies. However, these biomarkers must be validated in independent studies at different stages of the disease. The gene and protein expression profiles and protein distribution of six potential genetic biomarkers (i.e., CAPN6, COL1A2, COL3A1, GALA1, MT2A and MTNR1B) are presented here for both the early and terminal stages of scrapie in five different brain regions. Gene transcription changes were confirmed in the medulla oblongata, and the expression profiles were generally similar in other central nervous system regions. The changes were more substantial in clinical animals compared to preclinical animals. The expression of the CAPN6 protein increased in the spinal cord and cerebellum of the clinical and preclinical brains. The distribution of the GALA1 was identified in glial cells from the cerebellum of scrapie-infected animals, GALA1 protein expression was increased in clinical animals in the majority of regions, and the increase of MT2A was in agreement with previous reports. The downregulation of MTNR1B was especially marked in the Purkinje cells. Finally, although collagen genes were downregulated the protein immunostaining did not reveal significant changes between the scrapie-infected and control animals. In conclusion, this study of gene transcription and protein expression and distribution confirm CAPN6, GALA1, MTNR1B and MT2A as potential targets for further prion disease research.

Identification of Appropriate Reference Genes for qRT-PCR Analysis of Heat-Stressed Mammary Epithelial Cells in Riverine Buffaloes (Bubalus bubalis)

Gene expression studies require appropriate normalization methods for proper evaluation of reference genes. To date, not many studies have been reported on the identification of suitable reference genes in buffaloes. The present study was undertaken to determine the panel of suitable reference genes in heat-stressed buffalo mammary epithelial cells (MECs). Briefly, MEC culture from buffalo mammary gland was exposed to 42 °C for one hour and subsequently allowed to recover at 37 °C for different time intervals (from 30 m to 48 h). Three different algorithms, geNorm, NormFinder, and BestKeeper softwares, were used to evaluate the stability of 16 potential reference genes from different functional classes. Our data identified RPL4, EEF1A1, and RPS23 genes to be the most appropriate reference genes that could be utilized for normalization of qPCR data in heat-stressed buffalo MECs.

Peri-pubertal gonadotropin-releasing hormone analog treatment affects hippocampus gene expression without changing spatial orientation in young sheep

BACKGROUND

Normal brain maturation is the result of molecular changes that can be modulated by endocrine variables associated with brain plasticity and results in sex- and age specific changes in cognitive performance. Using a sheep model, we have previously shown that peri-pubertal pharmacological blockade of gonadotropin releasing hormone (GnRH) receptors results in increased sex-differences in cognitive executive function and emotional control. In this study we explore effects of this treatment regime on hippocampal gene expression and spatial orientation.

METHODS

The study was conducted with 30 same-sex twin lambs, half of which were treated with the GnRH analog (GnRHa) goserelin acetate every 4th week, beginning before puberty, until 50 weeks of age. Animals were tested in their spatial orientation ability at 48 weeks of age. Quantitative real time PCR analysis was conducted to examine effects of treatment on the expression of genes associated with synaptic plasticity and endocrine signaling.

RESULTS

GnRHa treatment was associated with significant sex- and hemisphere specific changes in mRNA expression for some of the genes studied. The treatment had no significant effect on spatial orientation. However, there was a tendency that females performed better than males in spatial orientation.

CONCLUSION

Our results indicate that GnRH directly and/or indirectly, is involved in the regulation of sex- and side-specific expression patterns of genes. Hence, these results should be considered when long-term peri-pubertal GnRHa treatment is used in children.

Comparative analysis of the Shadoo gene between cattle and buffalo reveals significant differences

Background

While prions play a central role in the pathogenesis of transmissible spongiform encephalopathies, the biology of these proteins and the pathophysiology of these diseases remain largely unknown. Since no case of bovine spongiform encephalopathy (BSE) has ever been reported in buffalo despite their phylogenetic proximity to cattle, genetic differences may be driving the different susceptibilities of these two species to BSE. We thus hypothesized that differences in expression of the most recently identified member of the prion family or Shadoo (SPRN) gene may relate to these species-specific differences.

Principal Findings

We first analyzed and compared the polymorphisms of the SPRN gene (∼4.4 kb), including the putative promoter, coding and 3′ regions, and further verified the entire ORF and putative promoter. This yielded a total of 117 fixed differences, remarkably: 1) a 12-bp insertion/deletion polymorphism in the hydrophobic domain of the cattle but not buffalo gene, introducing a four amino acid expansion/contraction in a series of 5 tandem Ala/Gly-containing repeats; 2) two fixed missense mutations (102Ser→Gly and 119Thr→Ala), and three missense mutations (92Pro>Thr/Met, 122Thr>Ile and 139Arg>Trp) in the coding region presenting different (P<0.05) genotypic and allelic frequency distributions between cattle and buffalo; and, 3) functional luciferase-reporter experiments for the predicted promoter region, consistent with a significantly higher activity in buffalo than cattle. Supporting these findings, immunoblotting revealed higher relative expression levels of Sho protein in cerebrum from buffalo than from cattle. In addition, for cattle, highest Sho expression was detected in obex, as compared to cerebrum or cerebellum.

Significance

Our findings support Sho as a non-PrP specific marker for prion infections, with obex as the best tissue source for the detection of Sho in TSE rapid tests. Moreover, these discoveries may prove advantageous for further understanding the biology of prion diseases.

Early postnatal kinetics of colostral immunoglobulin G absorption in fed and fasted piglets and developmental expression of the intestinal immunoglobulin G receptor

The transport of IgG across the epithelial barrier and into the circulation is achieved in part by the neonatal Fc receptor (FcRn), and this provides passive immunity to the neonate. The objective of this study was to determine the effect of time and feeding state on IgG absorption, intestinal morphology, and expression of IgG receptors in the first 24 h postbirth. Twenty newborn pigs were obtained immediately after birth and fitted with umbilical arterial catheters. Colostrum was manually collected from 12 lactating sows and centrifuged to produce defatted colostrum. Piglets were orally gavaged with 32 mL defatted colostrum per kilogram of BW (given in 2 doses 1 h apart) either at birth (0 h) or at 12 h postbirth under either fed (milk replacer) or fasted (saline solution) condition (n=5 per treatment). A fifth reference group (n=5) was euthanized at birth. Blood was collected every hour for the first 2 h immediately after the catheter was inserted and then every 4 h until 12 h (i.e., 0, 1, 2, 4, 8, and 12 h) for the treatment in which the defatted colostrum was given right after birth. For the treatment gavaged at 12 h postbirth, the sampling schedule was at 12, 13, 14, 16, 20, and 24 h. At 12 h postgavage, pigs were euthanized and jejunum tissues were collected for measurement of villi height, width, crypt depth, and gene expression of FcRn and β2-microglobulin (β2M) via reverse transcription PCR. Pig serum IgG concentration was determined by radial immunodiffusion. Data were analyzed according to a 2×2 factorial arrangement of treatments (0 h-fed, 0 h-fasted, 12 h-fed, and 12 h-fasted). There was no interaction between the time (age) of offering defatted colostrum (0 vs. 12 h) and nutritional state (fed vs. fasted) for any of the measurements, and there were no differences between fed and fasted pigs. Serum IgG concentrations increased progressively with time. Piglets offered defatted colostrum at 0 h had greater (P<0.05) overall IgG absorption and greater (P<0.05) villi height than those offered defatted colostrum at 12 h postbirth. Abundance of mRNA of FcRn and β2M were normalized to glyceraldehyde-3-phosphate dehydrogenase. Abundance of FcRn transcript was lower (P=0.006) in pigs euthanized at birth compared with those euthanized at 12 h of age. In conclusion, the effects of delayed offering of defatted colostrum and age-dependent changes in IgG receptor were modest over the first 24 h of life.

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

BACKGROUND

Mesenchymal 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.

RESULTS

Plastic-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.

CONCLUSIONS

This 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.

Differential gene expression and apoptosis markers in presymptomatic scrapie affected sheep

Neuronal loss is one of the characteristics of scrapie neuropathology. Previous analysis of brains from sheep naturally infected with scrapie that were in a terminal stage did not detect a clear induction of apoptosis, although molecular changes were evidenced. As neuronal death could be occurring early in scrapie, we developed a neuropathological and gene expression study of sheep infected with scrapie in a presymptomatic stage. The histopathology, immunolabelling of PrP(Sc), Bax and activated caspase-3, and the analysis of the expression of 7 genes involved in the regulation of the mitochondrial pathway of apoptosis were investigated in the following 4 central nervous system areas: medulla oblongata, diencephalon, frontal cortex and cerebellum. Moreover, TUNEL and NeuN immunolabelling was performed in the medulla oblongata. The PrP(Sc) immunolabelling in the four areas, as well as a neuropil spongiform change, were more evident in the terminal stage than in presymptomatic animals. Cytoplasmic Bax immunostaining was observed in the presymptomatic medulla oblongata. In contrast to symptomatic animals, the immunostaining was not extended to the hypothalamus, indicating the progression of Bax induction during the course of the disease. Although neither caspase-3 immunostaining nor the TUNEL technique detected neurons with apoptosis, NeuN-immunolabelled cell counting determined that presymptomatic animals have already suffered neuronal loss in a lower or equal degree than symptomatic animals. Finally, the gene expression profiles indicated that the mitochondrial pathway of apoptosis was activated with higher intensity in presymptomatic animals than in symptomatic sheep and confirmed the implication of genes such as BAX or AIF in the disease.