Modeling microRNA-driven post-transcriptional regulation using exon-intron split analysis in pigs

The contribution of microRNAs (miRNAs) to mRNA post-transcriptional regulation has often been explored by the post hoc selection of downregulated genes and determining whether they harbor binding sites for miRNAs of interest. This approach, however, does not discriminate whether these mRNAs are also downregulated at the transcriptional level. Here, we have characterized the transcriptional and post-transcriptional changes in mRNA expression in two porcine tissues: gluteus medius muscle of fasted and fed Duroc gilts and adipose tissue of lean and obese Duroc-Göttingen minipigs. Exon-intron split analysis of RNA-seq data allowed us to identify downregulated mRNAs with high post-transcriptional signals in fed or obese states, and we assessed whether they harbor binding sites for upregulated miRNAs in any of these two physiological states. We found 26 downregulated mRNAs with high post-transcriptional signals in the muscle of fed gilts and 21 of these were predicted targets of miRNAs upregulated in fed pigs. For adipose tissue, 44 downregulated mRNAs in obese minipigs displayed high post-transcriptional signals, and 25 of these were predicted targets of miRNAs upregulated in the obese state. These results suggest that the contribution of miRNAs to mRNA repression is more prominent in the skeletal muscle system. Finally, we identified several genes that may play relevant roles in the energy homeostasis of the pig skeletal muscle (DKK2 and PDK4) and adipose (SESN3 and ESRRG) tissues. By differentiating transcriptional from post-transcriptional changes in mRNA expression, exon-intron split analysis provides a valuable view of the regulation of gene expression, complementary to canonical differential expression analyses.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

The study shows that morbidly obese Göttingen Minipigs are protected against many of the metabolic and hepatic abnormalities associated with obesity due to a remarkable ability to expand the adipose compartments to accommodate excess calories.

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

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

Assessment of the decision support needs of women from HIV endemic countries regarding voluntary HIV testing in Canada

OBJECTIVE

To describe the decision support needs of immigrant and refugee women from HIV endemic countries regarding decision-making about voluntary counseling and testing for HIV (VCT) in Canada; and the needs of practitioners who support these women in making this decision, in a culturally appropriate manner.

METHODS

Adapted, semi-structured questionnaires, based on the Ottawa Decision Support Framework (ODSF), were used to interview practitioners and patients. Practitioners from diverse backgrounds were purposefully selected from centers providing VCT in Ottawa. Adult, English-speaking immigrant and refugee women from HIV endemic countries were recruited from a clinic specializing in immigrant health services. Responses were tabulated using descriptive statistics, and emerging themes coded to identify unique factors affecting decision-making.

RESULTS

Analysis revealed differences between practitioner and patient perceptions of the decision-making needs of women from HIV endemic countries regarding VCT. Practitioners identified women's lack of knowledge about HIV transmission and prevention as a primary need, while patients identified inadequate awareness of HIV screening and treatment services, and their benefits and harms. Patients also perceived that women would not be aware of the various VCT options, while few practitioners highlighted this concern. Both groups held similar viewpoints about counseling strategies that could improve decision-making.

CONCLUSION

Women were unaware of the options available to them for VCT. Both practitioners and patients highlighted the issue of stigma and negative outcomes associated with testing that created barriers or contributed to delays in women receiving testing. Women preferred anonymous testing, and recommended that information and decision support regarding HIV testing be provided via non-targeted strategies, and integrated within general health services or public education.

PRACTICE IMPLICATIONS

Decision support in the context of VCT can improve decision quality, empowering patients to make informed decisions based on personal values. Study findings can inform the development of clinical guidelines for the routine offering of VCT.

Investigating the decision-making needs of HIV-positive women in Africa using the Ottawa Decision-Support Framework: Knowledge gaps and opportunities for intervention

OBJECTIVE

To examine HIV-positive women's decision making in the context of pregnancy and HIV/AIDS and to explore interventions that may enhance and develop women's decision-making capacity in the sub-Saharan African context.

METHODS

The Ottawa Decision-Support Framework was used to assemble evidence of women's decision-making needs. Several electronic databases were searched and an Internet search of the World Wide Web was conducted to search grey literature sources. An evidence-based approach to assessing benefits, harms and current practices was employed.

RESULTS

Several gaps in our knowledge about women's decision making in the context of pregnancy and HIV were identified. The availability of evidence varied for each decision; however, significant gaps included: evidence around testing for ones status, advanced directives for self and child, disclosure (specifically, the impact of), others perceptions of antiretroviral use and data on termination of pregnancies.

CONCLUSION

Decision making as a concept was generally not addressed in the MTCT literature. Evidence regarding the perceptions of women and others regarding the various decisions was often not available and subsequently an important aspect of MTCT interventions neglected.

PRACTICE IMPLICATIONS

Incorporating a multi-disciplinary decision-support framework may prove useful to promote women's autonomy and involvement in MTCT-related decision making.

Competencies related to medication administration and monitoring

Reconfiguration of health service delivery has raised questions and concerns about the category of provider qualified to administer and monitor medications on inpatient units. The competency base (i.e. the scope of knowledge, skills and judgements) required, is dependent on the health status of the patient population and the medications prescribed. As part of a larger study addressing nurse competencies (Alcock, 1995), the required knowledge, skills and clinical judgement related to medication administration and monitoring for patients on two long term care units in a long term care facility and two tertiary care units in a general teaching hospital were determined. The total number of medications prescribed across the four units varied from 120 to 256 medications per unit. The number of different drug classes ranged from 27 to 32 per unit and the potential for drug-drug interactions ranged from 47% to 66% of prescribed medications across the units. The findings provide an information base for decisions related to education and to staffing. Various nursing delivery system options and factors which influence competency are discussed.

Experimental vaccination of pigs with an Actinobacillus pleuropneumoniae serotype 5b capsular polysaccharide-tetanus toxoid conjugate

The protective efficacy of an Actinobacillus pleuropneumoniae serotype 5b capsular polysaccharide-tetanus toxoid conjugate (Ap5bCP-TT) against homologous challenge of pigs was investigated. Four pigs were non-vaccinated controls (group A), 4 pigs were injected with adjuvant without antigen (group B) and 8 pigs were vaccinated with Ap5bCP-TT and adjuvant (group C). Pigs vaccinated with Ap5bCP-TT developed antibody responses to the capsular polysaccharide from A. pleuropneumoniae serotype 5b (Ap5bCP). After challenge, all pigs in groups A and B had severe clinical signs of disease and were euthanized. In group C, 3 out of 8 pigs showed severe symptoms and were euthanized. Five pigs in group C survived throughout the study. The post challenge observation period was 72 h. All pigs were subject to necropsy and results from gross pathological findings and microbiological examination are described. Pigs vaccinated with Ap5bCP-TT had statistically significant reduced values of the mass ratio of affected to unaffected lung tissue compared to pigs in groups A and B (p = 0.01 and p = 0.007, respectively). The results showed that Ap5bCP-TT-vaccination had considerable protective efficacy against lethality and pulmonary lesions caused by experimental infection with A. pleuropneumoniae serotype 5b.

Comparison of virulence of different Actinobacillus pleuropneumoniae serotypes and biotypes using an aerosol infection model

An aerosol infection model for inoculation of pigs with Actinobacillus pleuropneumoniae is described. With this model the virulence of three A. pleuropneumoniae biotype 1 strains representing serotypes 2, 5b and 6, and one Danish biotype 2 were compared using 13-week-old pigs for inoculation. The pigs were sacrificed 24 h after aerosol exposure and lung lesions were evaluated. In pigs exposed to aerosols of suspensions containing 10(4) CFU/ml of serotypes 2, 5b and 6, a number of 5-10 lesions of haemorrhagic necrotizing pneumonia were induced. For the biotype 2 strain the dose creating similar lesions was 10(9) CFU/ml. Repeated experiments confirmed these results showing similar virulence of serotypes 2, 5b and 6 whereas the biotype 2 strain proved less virulent. The aerosol infection model allowed a comparison of the number of A. pleuropneumoniae CFU/liter air which were necessary to induce lung lesions in susceptible pigs. This indicates that the model will be well suited for virulence studies of A. pleuropneumoniae serotypes in pigs.

Development and evaluation of a selective and indicative medium for isolation of Actinobacillus pleuropneumoniae from tonsils

In order to isolate Actinobacillus pleuropneumoniae from mixed bacterial flora a selective and indicative medium was developed. The optimal concentrations of antibiotics were determined for selective chocolate agar (S-TSA) and selective blood agar (S-MBA) using a set of 25 strains of A. pleuropneumoniae. Following optimization of the media 96 isolates of A. pleuropneumoniae were tested on S-TSA and S-MBA. For isolation of A. pleuropneumoniae from 101 pig tonsils collected at slaughter the S-MBA proved significantly better than both S-TSA and the two non-selective agars tested. Furthermore, contaminating to S-TSA and the two non-selective media.

[Incidence of MMA after prostaglandin-induced parturition (author's transl)]

In a sowherd suffering from high incidence of MMA which demanded an intensive postparturient treatment to reduce baby pig mortality the effect on postparturient diseases of induction of parturition with Prostaglandin was examined. After treatment of 19 sows on day 112 of gestation with 12.5 mg Prostaglandin, parturition in 15 sows took place on an average of 25 hours after injection; the gestation period was 113.1 +/- 0.5 days. Three sows that did not respond to the treatment farrowed 3-6 days after treatment and one sow farrowed few hours after treatment. In a non-treated identical group of animals the gestation period averaged 113.4 +/- 1.5 days. No difference was found between the two groups concerning number of stillborn pgis, baby pig mortality within first eight days of life, incidence of MMA or intensity of postparturient medical treatment.